Stem cells are highly resistant to viral infection compared to their differentiated progeny, and this resistance is associated with stem cell-specific restriction factors and intrinsic interferon stimulated genes (ISGs). In HIV infection, proviral DNA has been detected in certain bone marrow hematopoietic stem cells, yet widespread stem cell infection in vivo is restricted. Intriguingly, exposing bone marrow stem cells to HIV in vitro led to viral replication selectively only in the CD34- population, but not in the CD34+ cells. The mechanism dictating this CD34-based HIV restriction remained a mystery, especially since HIV has a capacity to antagonize restriction factors and ISGs. CD34 is a common marker of hematopoietic stem and progenitor cells. Here, we report the intrinsic antiviral properties of CD34. Expression of CD34 in HIV-1 producer cells results in the loss of progeny virion infectivity. Conversely, removal of CD34 using CRISPR/Cas9 knockout or stem cell differentiation cytokines promotes HIV-1 replication in stem cells. These results suggest that in addition to restriction factors and intrinsic ISGs, CD34 serves as a host innate protection preventing retrovirus replication in stem cells. Mechanistically, CD34 does not block viral entry, integration, and release. Instead, it becomes incorporated onto progeny virions, which inactivates virus infectivity. These findings offer new insights into innate immunity in stem cells, and highlight intriguing retrovirus-host interactions in evolution.

Patients with younger onset of type 2 diabetes (YT2D) have increased risk for kidney failure compared to those with late onset. However, the mechanism of diabetic kidney disease (DKD) progression in this high-risk group is poorly understood.

This work aimed to identify novel biomarkers and potential causal proteins associated with DKD progression in patients with YT2D.

Among YT2D (T2D onset age <40 years), 144 DKD progressors (cases) were matched for T2D onset age, sex, and ethnicity with 292 nonprogressors (controls) and divided into discovery and validation sets. DKD progression was defined as decline of estimated glomerular filtration rate (eGFR) of 3 mL/min/1.73 m2 or greater or 40% decline in eGFR from baseline. A total of 1472 plasma proteins were measured through a multiplex immunoassay that uses a proximity extension assay technology. Multivariable logistic regression was used to identify proteins associated with DKD progression. Mendelian randomization (MR) was used to evaluate causal relationship between plasma proteins and DKD progression.

Forty-two plasma proteins were associated with DKD progression, independent of traditional cardiorenal risk factors, baseline eGFR, and urine albumin-to-creatinine ratio. The proteins identified were related to inflammatory and remodeling biological processes. Our findings suggest angiogenin as one of the top signals (odds ratio = 5.29; 95% CI, 2.39-11.73; P = 4.03 × 10-5). Furthermore, genetically determined plasma angiogenin level was associated with increased odds of DKD progression.

Large-scale proteomic analysis identified novel proteomic biomarkers for DKD progression in YT2D. Genetic evidence suggest a causal role of plasma angiogenin in DKD progression.

Hereditary hemorrhagic telangiectasia is an autosomal dominant disorder caused by mutations in the bone morphogenetic protein signaling pathway, leading to arteriovenous malformations. While previously thought to share molecular and cellular dysregulation, this study reveals highly distinct mechanisms depending on whether mutations occur in Alk1 or SMAD4. Loss of SMAD4 enhances endothelial cell responses to flow, including flow-regulated transcription and cell migration against blood flow, causing excessive pruning of capillaries and the formation of single large shunts. Conversely, Alk1 deficiency disrupts endothelial flow responses, including cell polarization and directional migration, leading to a dense vascular network and the persistence of a malformation nidus. In vivo cell population tracking of mutant cells validates unique endothelial cell migration defects. Mosaic cell culture models further illustrate that mutant cells co-opt wild-type cells driving distinct Alk1 or SMAD4 mutant-like behavioral defects. These findings demonstrate that arteriovenous malformations develop through fundamentally different cellular mechanisms based on the specific genetic mutation emphasizing the need for tailored diagnostic and therapeutic strategies.

Objectives: The downregulation of anti-adhesive regulatory proteins and upregulation of adhesive genes are critical for the receptive endometrium. This study was designed to determine whether switching between the anti-adhesive podocalyxin (PDX) and adhesive HOXA10 receptivity modulator occurs in the endometrium of women with recurrent implantation failure (RIF). Methods: Twenty-four patients with RIF who could not conceive for three or more cycles despite good-quality embryo transfer constituted the study group. Twenty-four patients with unexplained infertility (UEI) matched for age, BMI, and infertility duration were included in the control group. Twenty women scheduled to undergo intrauterine device (IUD) placement for birth control were included in the comparative group. Endometrial tissue was collected from patients with RIF and UEI during egg retrieval after ovarian stimulation using the GnRH antagonist protocol. In the fertile group, endometrial tissues were collected during IUD insertion. HOXA10 mRNA expression was analyzed by qRT-PCR and PDX protein expression was analyzed by ELISA. The relative expression of endometrial HOXA10 mRNA was calculated using the 2-ΔΔCt equation. Results: The relative expression of HOXA10 mRNA in the RIF group was significantly lower than that in the UEI group (p < 0.001). HOXA10 mRNA expression in the fertile group was significantly higher than that in the RIF group and was similar to that in the UEI group. PDX expression in the RIF group was significantly higher than that in the UEI group (p < 0.001). PDX expression in the fertile group was significantly lower than in the RIF and UEI groups. A negative correlation was detected between the anti-adhesive PDX protein and adhesive HOXA10 (r = -0.797, p < 0.001). Although there was a positive correlation between endometrial thickness recorded on the day of hCG administration and HOXA10 (r = 0.590, p < 0.01), endometrial thickness was negatively correlated with PDX (r = -0.529, p < 0.01). Conclusions: The failed physiological downregulation of the anti-adhesive PDX protein in patients with RIF prevented the upregulation of adhesive HOXA10 mRNA.

To investigate whether endometrial receptivity is affected in patients with endometriosis using podocalyxin (PCX) as a functional biomarker and to study how endometriotic lesions display PCX and the potential pathological implications.

We have previously reported that PCX, an anti-adhesion glycoprotein and barrier protector, is dynamically regulated in the endometrium and acts as a key negative regulator of epithelial receptivity. Early in the cycle both luminal epithelium (LE, lining the endometrial surface) and glandular epithelium (GE, residing within the tissue) strongly express PCX, but in the receptive window, PCX is selectively downregulated in LE, switching the endometrial surface to an adhesive state for embryo attachment/implantation; meanwhile, PCX expression is maintained in GE until postreceptivity. Here, we immuno-stained PCX in endometrial tissues and ectopic lesions biopsied across the menstrual cycle from patients with endometriosis (EOS, n = 41), and compared with endometrium of non-endometriosis controls (non-EOS, n = 55). We further investigated how PCX changes observed in ectopic lesions may influence their adhesive capacity.

RMIT University, Australia.

Women without and with endometriosis.

Not applicable.

The window of endometrial receptivity might be shorter in patients with endometriosis; ectopic sites in addition downregulate PCX cyclically, mirroring the eutopic endometrial cells in preparing for receptivity to increase their adhesion potential.

Endometrial PCX levels were comparable between non-EOS and EOS early in the cycle, and in both groups, PCX is downregulated in LE during the expected window of receptivity; however, in EOS endometrium, PCX is reduced earlier in GE as if the receptive window were shorter. In endometriotic lesions, PCX was detected in endometrial LE- and GE-like cells plus mesothelial cells enveloping peritoneal organs, but PCX was cyclically lost specifically in LE-like cells and reduced in GE-like cells as seen in the eutopic endometrium, which however may increase their adhesion potential to nearby organs (overlaid by mesothelial cells). This speculation was further corroborated in an in vitro model showing endometrial epithelial cells with lower PCX were indeed more adhesive to mesothelial cells.

Endometrial receptivity is subtly affected in patients with endometriosis with a shorter window. Cyclic downregulation of PCX in ectopic sites may have pathological consequences.

Various osteogenic factors are involved in ectopic human aortic valve calcification; however, the key cell species involved in calcification remains unclear. In a previous study, we reported that mesenchymal stem (CD73, 90, 105) and endothelial (VEGFR2) cell markers are positive in almost all human aortic valve interstitial cells (HAVICs) obtained from a patient with calcified aortic valve stenosis (CAVS). Further, CD34-negative HAVICs are highly sensitive to calcification stimulations. Here, we aimed to pathophysiologically clarify the role of CD34 in HAVICs obtained from individual patients with severe CAVS. A DNA microarray between CD34-positive and CD34-negative HAVICs, separated by fluorescence-activated cell sorting, indicated that tenascin X (TNX) mRNA expression significantly decreased in CD34-negative cells. Furthermore, the inflammatory cytokines, tumor necrosis factor (TNF)-α and interleukin (IL)-1β significantly downregulated CD34 expression in HAVICs. TGF-β, a key cytokine of endothelial-mesenchymal transition, did not affect HAVIC calcification. CD34 overexpression strongly inhibited TNF-α- and IL-1β-induced calcification and maintained TNX mRNA expression. These results suggest one possibility that CD34 is an inhibitory regulator of valve calcification. Furthermore, TNF-α- and IL-1β-induced CD34 downregulation in HAVICs contributes to HAVIC calcification by downregulating TNX protein expression.

Telocytes (TCs) are a distinctive cell entity of the stromal microenvironment of multiple tumors; to date, their existence in infantile hemangioma (IH) remains almost unexplored. This study was therefore undertaken to characterize the immunophenotype, location, morphology, and ultrastructure of telocytes in the IH by means of immunohistochemistry, immunofluorescence confocal microscopy, and transmission electron microscopy. Telocytes were initially identified by CD34, PDGFR-α, Vimentin, and AQP-1 immunostaining. Analyzing the spatial relationship among telocytes, stem cells, endothelial cells, pericytes in the IH with AQP-1/CD31, AQP-1/Glut-1, AQP-1/α-SMA, AQP-1/CD146 and AQP-1/CD133 double immunofluorescence. TCs were immunonegative for CD31, Glut-1, CD146, α-SMA, CD133, and C-kit in the IH. The ultrastructural examination confirmed the presence of TCs, namely stromal cells with characteristic cytoplasmic processes (i.e. telopodes) forming labyrinthine networks around microvessels and releasing extracellular vesicles. Our study provides evidence that telocytes are present and PDGFR-α and AQP-1 are specific antigenic markers in the IH.

Stress-inducible heat shock protein 70 (Hsp70), which functions as a molecular chaperone and is frequently overexpressed in different cancer cell types, is present on the cell surface of tumor cells and is actively released into the circulation in free and extracellular lipid vesicle-associated forms. Since the exact pathomechanism of endometriosis has not yet been elucidated (although it has been associated with the development of endometrial and ovarian cancer), we asked whether extracellular Hsp70 and circulating endometriotic cells (CECs) reflect the presence and development of endometriosis. Therefore, circulating levels of free and lipid microvesicle-associated Hsp70 were measured using the Hsp70-exo ELISA, and the presence of circulating CECs in the peripheral blood of patients with endometriosis was determined using membrane Hsp70 (mHsp70) and EpCAM monoclonal antibody (mAb)-based bead isolation approaches. Isolated CECs were further characterized by immunofluorescence using reagents directed against cytokeratin (epithelial marker), CD45 (leukocyte marker), CD105/CD44 (mesenchymal stemness markers) and by comparative RNA analysis. Similar to the situation in patients with cancer, the levels of circulating Hsp70 were elevated in the blood of patients with histologically proven endometriosis compared to a healthy control cohort, with significantly elevated Hsp70 levels in endometriosis patients with lesions outside the uterine cavity. Moreover, CECs could be isolated using the cmHsp70.1 mAb-based, and to a lesser extent EpCAM mAb-based, bead approach in all patients with endometriosis, with the highest counts obtained using the mHsp70-targeting procedure in patients with extra-uterine involvement. The longevity in cell culture and the expression of the cytokeratins CD105 and CD44, together with differentially expressed genes related to epithelial-to-mesenchymal transition (EMT), revealed similarities between mHsp70-expressing CECs and circulating tumor cells (CTCs) and suggest a mesenchymal stem cell origin. These findings support the involvement of mHsp70-positive stem cell-like cells in the development of endometriotic lesions. In summary, elevated levels of Hsp70 and CECs in the circulation could serve as liquid biopsy markers for endometriosis with extra-uterine involvement and help to elucidate the underlying pathomechanism of the disease.

Acute myeloid leukemia (AML) is a hostile hematological malignancy under great danger of relapse and poor long-term survival rates, despite recent therapeutic advancements. To deal with this unfulfilled clinical necessity, innovative cell-based immunotherapies have surfaced as promising approaches to improve anti-tumor immunity and enhance patient outcomes. In this comprehensive review, we provide a detailed examination of the latest developments in cell-based immunotherapies for AML, including chimeric antigen receptor (CAR) T-cell therapy, T-cell receptor (TCR)-engineered T-cell therapy, and natural killer (NK) cell-based therapies. We critically evaluate the unique mechanisms of action, current challenges, and evolving strategies to improve the efficacy and safety of these modalities. The review emphasizes how promising these cutting-edge immune-based strategies are in overcoming the inherent complexities and heterogeneity of AML. We discuss the identification of optimal target antigens, the importance of mitigating on-target/off-tumor toxicity, and the need to enhance the persistence and functionality of engineered immune effector cells. All things considered, this review offers a thorough overview of the rapidly evolving field of cell-based immunotherapy for AML, underscoring the significant progress made and the ongoing efforts to translate these innovative approaches into more effective and durable treatments for this devastating disease.

Pathological changes in the central nervous system (CNS) begin before the clinical symptoms of Alzheimer's Disease (AD) manifest, with the hippocampus being one of the first affected structures. Current treatments fail to alter AD progression. Traditional Chinese medicine (TCM) has shown potential in improving AD pathology through multi-target mechanisms. This study investigates pathological changes in AD hippocampal tissue and explores TCM active components that may alleviate these changes.

GSE5281 and GSE173955 datasets were downloaded from GEO and normalized to identify differentially expressed genes (DEGs). Key functional modules and hub genes were analyzed using Cytoscape and R. Active TCM components were identified from literature and the Pharmacopoeia of the People's Republic of China. Enrichment analyses were performed on target genes overlapping with DEGs.

From the datasets, 76 upregulated and 363 downregulated genes were identified. Hub genes included SLAMF, CD34, ELN (upregulated) and ATP5F1B, VDAC1, VDAC2, HSPA8, ATP5F1C, PDHA1, UBB, SNCA, YWHAZ, PGK1 (downregulated). Literature review identified 33 active components from 23 herbal medicines. Target gene enrichment and analysis were performed for six components: dihydroartemisinin, berberine, naringenin, calycosin, echinacoside, and icariside II.

Mitochondrial to synaptic vesicle dysfunction pathways were enriched in downregulated genes. Despite downregulation, UBB and SNCA proteins accumulate in AD brains. TCM studies suggest curcumin and echinacoside may improve hippocampal pathology and cognitive impairment in AD. Further investigation into their mechanisms is needed.

Lipogenic and fibrous tumors are thought to originate from CD34-positive stromal fibroblastic/fibrocystic cells. Well-differentiated lipogenic tumors typically express CD34, whereas dedifferentiated liposarcoma (DDLPS) often loses it. We conducted survival analyses involving 59 patients with DDLPS. Males comprised 53% of the cohort, and the median age at the time of wide resection of primary DDLPS was 60 years. Loss of CD34 expression was defined as when ≥50% of the dedifferentiated area was immunohistochemically negative for CD34. As a result, 39 of the 59 patients showed loss of CD34 expression during the initial operation for DDLPS. In the univariate analyses, the tumor site in the retroperitoneum/abdominal cavity and loss of CD34 expression were significantly associated with poor overall survival. In the multivariate analyses, loss of CD34 expression (HR = 2.26; 95% CI = 1.02-5.02; p = 0.04) and the tumor site in the retroperitoneum/abdominal cavity (HR = 3.11; 95% CI = 1.09-8.86; p = 0.03) were retained as independent prognostic factors. Six CD34-positive cases lost CD34 expression when they developed metastasis and/or local recurrence, suggesting that the loss was associated with the later stage of the tumor. Therefore, an association existed between the loss of CD34 expression and clinicopathological behaviors such as poorer prognoses and recurrence.

Umbilical cord blood (UCB) is a rich source of beneficial stem and progenitor cells with known angiogenic, neuroregenerative and immune-modulatory properties. Preclinical studies have highlighted the benefit of UCB for a broad range of conditions including haematological conditions, metabolic disorders and neurological conditions, however clinical translation of UCB therapies is lacking. One barrier for clinical translation is inadequate cell numbers in some samples meaning that often a therapeutic dose cannot be achieved. This is particularly important when treating adults or when administering repeat doses of cells. To overcome this, UCB cell expansion is being explored to increase cell numbers. The current focus of UCB cell expansion is CD34+ haematopoietic stem cells (HSCs) for which the main application is treatment of haematological conditions. Currently there are 36 registered clinical trials that are examining the efficacy of expanded UCB cells with 31 of these being for haematological malignancies. Early data from these trials suggest that expanded UCB cells are a safe and feasible treatment option and show greater engraftment potential than unexpanded UCB. Outside of the haematology research space, expanded UCB has been trialled as a therapy in only two preclinical studies, one for spinal cord injury and one for hind limb ischemia. Proteomic analysis of expanded UCB cells in these studies showed that the cells were neuroprotective, anti-inflammatory and angiogenic. These findings are also supported by in vitro studies where expanded UCB CD34+ cells showed increased gene expression of neurotrophic and angiogenic factors compared to unexpanded CD34+ cells. Preclinical evidence demonstrates that unexpanded CD34+ cells are a promising therapy for neurological conditions where they have been shown to improve multiple indices of injury in rodent models of stroke, Parkinson's disease and neonatal hypoxic ischemic brain injury. This review will highlight the current application of expanded UCB derived HSCs in transplant medicine, and also explore the potential use of expanded HSCs as a therapy for neurological conditions. It is proposed that expanded UCB derived CD34+ cells are an appropriate cellular therapy for a range of neurological conditions in children and adults.

Hematopoietic stem cells emerge in the embryo from an aortic-derived tissue called the hemogenic endothelium (HE). The HE appears to give birth to cells of different nature and fate but the molecular principles underlying this complexity are largely unknown. Here we show, in the zebrafish embryo, that two cell types emerge from the aortic floor with radically different morphodynamics. With the support of live imaging, we bring evidence suggesting that the mechanics underlying the two emergence types rely, or not, on apicobasal polarity establishment. While the first type is characterized by reinforcement of apicobasal polarity and maintenance of the apical/luminal membrane until release, the second type emerges via a dynamic process reminiscent of trans-endothelial migration. Interfering with Runx1 function suggests that the balance between the two emergence types depends on tuning apicobasal polarity at the level of the HE. In support of this and unexpectedly, we show that Pard3ba - one of the four Pard3 proteins expressed in the zebrafish - is sensitive to interference with Runx1 activity, in aortic endothelial cells. This supports the idea of a signaling cross talk controlling cell polarity and its associated features, between aortic and hemogenic cells. In addition, using new transgenic fish lines that express Junctional Adhesion Molecules and functional interference, we bring evidence for the essential role of ArhGEF11/PDZ-RhoGEF in controlling the HE-endothelial cell dynamic interface, including cell-cell intercalation, which is ultimately required for emergence completion. Overall, we highlight critical cellular and dynamic events of the endothelial-to-hematopoietic transition that support emergence complexity, with a potential impact on cell fate.

The association of periodontal disease and diabetes is a subject of intense research in terms of etiopathology and treatment options. This research aimed to evaluate the modulation of the local inflammatory status by two natural extracts, curcumin (Cu) and rutin (R), in an experimentally induced diabetes and periodontal disease in Wistar rats.

Fifty Wistar albino rats were randomly assigned to five groups: Control (C), Diabetes-associated Periodontal Disease (DP), Diabetes-associated Periodontal Disease treated with Curcumin (DPCu), Diabetes-associated Periodontal Disease treated with Rutin (DPR), and Diabetes-associated Periodontal Disease treated with both Curcumin and Rutin (DPCuR). Gingival samples were collected from all rats, and immunohistochemical markers CD3, CD20, and CD34 were evaluated to assess the local inflammatory infiltrate. Descriptive statistics were applied (SPSS24 Software, Armonk, NY, USA).

Rutin, alone or combined with Curcumin, reduced CD3-positive cell levels. Curcumin demonstrated superior efficacy in reducing CD20-positive cells. The combination of Curcumin and Rutin had the most important impact on both markers. Curcumin notably increased immature CD34-positive cell levels.

Curcumin and Rutin, either alone or together, hold potential for reducing local inflammation in diabetes-induced periodontal disease in Wistar rats.

Little is known about morphogenetic changes in the umbilical cord during the maturation process. Extracellular matrix remodeling, angiogenesis, progenitor activity, and immunomodulation are represented by specific markers; therefore, the aim of this study was to determine the expression of matrix metalloproteinase-2 (MMP2), tissue inhibitor of metalloproteinases-2 (TIMP2), CD34, vascular endothelial growth factor (VEGF), and human β-defensin 2 (HBD2) in preterm and full-term human umbilical cord tissue.

Samples of umbilical cord tissue were obtained from 17 patients and divided into two groups: very preterm and moderate preterm birth umbilical cords; late preterm birth and full-term birth umbilical cords. Routine histology examination was conducted. Marker-positive cells were detected using the immunohistochemistry method. The number of positive structures was counted semi-quantitatively using microscopy. Statistical analysis was carried out using the SPSS Statistics 29 program.

Extraembryonic mesenchyme cells are the most active cell producers, expressing MMP2, TIMP2, VEGF, and HBD2 at notable levels in preterm and full-term umbilical cord tissue. Statistically significant differences in the expression of CD34, MMP2, and TIMP2 between the two patient groups were found. The expression of VEGF was similar in both patient groups, with the highest number of VEGF-positive cells seen in the extraembryonic mesenchyme. The expression of HBD2 was the highest in the extraembryonic mesenchyme and the amniotic epithelium, where mostly moderate numbers of HBD2-positive cells were detected.

Extracellular matrix remodeling in preterm and term umbilical cords is strongly regulated, and tissue factors MMP2 and TIMP2 take part in this process. The expression of VEGF is not affected by the umbilical cord's age; however, individual patient factors can affect the production of VEGF. Numerous CD34-positive cells in the endothelium of the umbilical arteries suggest a significant role of progenitor cells in very preterm and moderate preterm birth umbilical cords. Antimicrobial activity provided by HBD2 is essential and constant in preterm and full-term umbilical cords.

Lactate and ATP formation by aerobic glycolysis, the Warburg effect, is considered a hallmark of cancer. During angiogenesis in non-cancerous tissue, proliferating stalk endothelial cells (ECs) also produce lactate and ATP by aerobic glycolysis. In fact, all proliferating cells, both non-cancer and cancer cells, need lactate for the biosynthesis of building blocks for cell growth and tissue expansion. Moreover, both non-proliferating cancer stem cells in tumors and leader tip ECs during angiogenesis rely on glycolysis for pyruvate production, which is used for ATP synthesis in mitochondria through oxidative phosphorylation (OXPHOS). Therefore, aerobic glycolysis is not a specific hallmark of cancer but rather a hallmark of proliferating cells and limits its utility in cancer therapy. However, local treatment of angiogenic eye conditions with inhibitors of glycolysis may be a safe therapeutic option that warrants experimental investigation. Most types of cells in the eye such as photoreceptors and pericytes use OXPHOS for ATP production, whereas proliferating angiogenic stalk ECs rely on glycolysis for lactate and ATP production. (J Histochem Cytochem XX.XXX-XXX, XXXX).

Early gene therapy studies held great promise for the cure of heritable diseases, but the occurrence of various genotoxic events led to a pause in clinical trials and a more guarded approach to progress. Recent advances in genetic engineering technologies have reignited interest, leading to the approval of the first gene therapy product targeting genetic mutations in 2017. Gene therapy (GT) can be delivered either in vivo or ex vivo. An ex vivo approach to gene therapy is advantageous, as it allows for the characterization of the gene-modified cells and the selection of desired properties before patient administration. Autologous cells can also be used during this process which eliminates the possibility of immune rejection. This review highlights the various stages of ex vivo gene therapy, current research developments that have increased the efficiency and safety of this process, and a comprehensive summary of Human Immunodeficiency Virus (HIV) gene therapy studies, the majority of which have employed the ex vivo approach.

The development of the metanephros in one-humped camels involves a complex series of interactions between epithelial and mesenchymal cells. As a result, there is a synchronized differentiation process of stromal, vascular and epithelial cell types during glomerulogenesis, angiogenesis and tubulogenesis. In the current work, the metanephros of camel foetuses were divided into four stages where kidneys from each stage were processed and immunoassayed, followed by quantitative analysis to determine target protein intensities throughout metanephrogenesis in the camel. This study demonstrated robust expression of α-smooth muscle actin (α-SMA) in the glomerular mesangium, as well as in interlobular and glomerular arterioles during the earlier stages of development. However, in the late stages, α-SMA expression became more localized around the blood capillaries in both the cortex and medulla. Strong expression of CD34 was observed in the immature glomerular and peritubular endothelial cells within the subcapsular zone, as well as in the glomerular, proximal tubular and distal tubular epithelium of stage one foetuses, although its expression gradually diminished with foetal maturation. The expression pattern of osteopontin was prominently observed in the distal convoluted tubules throughout all stages, however, no expression was detected in the proximal tubules, glomeruli and arterioles. E-cadherin was detected in the developing renal tubular epithelial cells but not in the glomeruli. In conclusion, this study reveals the spatiotemporal distribution of key proteins, including α-SMA, CD34, Osteopontin and E-cadherin, which play a crucial role in metanephrogenesis in camel foetuses.

Targeted-immunotherapies such as antibody-drug conjugates (ADC), chimeric antigen receptor (CAR) T cells or bispecific T-cell engagers (eg, BiTE®) all aim to improve cancer treatment by directly targeting cancer cells while sparing healthy tissues. Success of these therapies requires tumor antigens that are abundantly expressed and, ideally, tumor specific. The CD34-related stem cell sialomucin, podocalyxin (PODXL), is a promising target as it is overexpressed on a variety of tumor types and its expression is consistently linked to poor prognosis. However, PODXL is also expressed in healthy tissues including kidney podocytes and endothelia. To circumvent this potential pitfall, we developed an antibody, named PODO447, that selectively targets a tumor-associated glycoform of PODXL. This tumor glycoepitope is expressed by 65% of high-grade serous ovarian carcinoma (HGSOC) tumors.

In this study we characterize these PODO447-expressing tumors as a distinct subset of HGSOC using four different patient cohorts that include pre-chemotherapy, post-neoadjuvant chemotherapy (NACT) and relapsing tumors as well as tumors from various peritoneal locations.

We find that the PODO447 epitope expression is similar across tumor locations and negligibly impacted by chemotherapy. Invariably, tumors with high levels of the PODO447 epitope lack infiltrating CD8+ T cells and CD20+ B cells/plasma cells, an immune phenotype consistently associated with poor outcome.

We conclude that the PODO447 glycoepitope is an excellent biomarker of immune "cold" tumors and a candidate for the development of targeted-therapies for these hard-to-treat cancers.

Podocalyxin (PODXL) overexpression is associated with poor clinical outcomes in various tumors. PODXL is involved in tumor malignant progression through the promotion of invasiveness and metastasis. Therefore, PODXL is considered a promising target of monoclonal antibody (mAb)-based therapy. However, PODXL also plays an essential role in normal cells, such as vascular and lymphatic endothelial cells. Therefore, cancer specificity or selectivity is required to reduce adverse effects on normal cells. Here, we developed an anti-PODXL cancer-specific mAb (CasMab), PcMab-6 (IgG1, kappa), by immunizing mice with a soluble PODXL ectodomain derived from a glioblastoma LN229 cell. PcMab-6 reacted with the PODXL-positive LN229 cells but not with PODXL-knockout LN229 cells in flow cytometry. Importantly, PcMab-6 recognized pancreatic ductal adenocarcinoma (PDAC) cell lines (MIA PaCa-2, Capan-2, and PK-45H) but did not react with normal lymphatic endothelial cells (LECs). In contrast, one of the non-CasMabs, PcMab-47, showed high reactivity to both the PDAC cell lines and LECs. Next, we engineered PcMab-6 into a mouse IgG2a-type (PcMab-6-mG2a) and a humanized IgG1-type (humPcMab-6) mAb and further produced the core fucose-deficient types (PcMab-6-mG2a-f and humPcMab-6-f, respectively) to potentiate the antibody-dependent cellular cytotoxicity (ADCC). Both PcMab-6-mG2a-f and humPcMab-6-f exerted ADCC and complement-dependent cellular cytotoxicity in the presence of effector cells and complements, respectively. In the PDAC xenograft model, both PcMab-6-mG2a-f and humPcMab-6-f exhibited potent antitumor effects. These results indicated that humPcMab-6-f could apply to antibody-based therapy against PODXL-expressing pancreatic cancers.

Accurate and efficient classification and quantification of CD34+ cells are essential for the diagnosis and monitoring of leukemia. Current methods, such as flow cytometry, are complex, time-consuming, and require specialized expertise and equipment. This study proposes a novel approach for the label-free identification of CD34+ cells using a deep learning model and lens-free shadow imaging technology (LSIT). LSIT is a portable and user-friendly technique that eliminates the need for cell staining, enhances accessibility to nonexperts, and reduces the risk of sample degradation. The study involved three phases: sample preparation, dataset generation, and data analysis. Bone marrow and peripheral blood samples were collected from leukemia patients, and mononuclear cells were isolated using Ficoll density gradient centrifugation. The samples were then injected into a cell chip and analyzed using a proprietary LSIT-based device (Cellytics). A robust dataset was generated, and a custom AlexNet deep learning model was meticulously trained to distinguish CD34+ from non-CD34+ cells using the dataset. The model achieved a high accuracy in identifying CD34+ cells from 1929 bone marrow cell images, with training and validation accuracies of 97.3% and 96.2%, respectively. The customized AlexNet model outperformed the Vgg16 and ResNet50 models. It also demonstrated a strong correlation with the standard fluorescence-activated cell sorting (FACS) technique for quantifying CD34+ cells across 13 patient samples, yielding a coefficient of determination of 0.81. Bland-Altman analysis confirmed the model's reliability, with a mean bias of -2.29 and 95% limits of agreement between 18.49 and -23.07. This deep-learning-powered LSIT offers a groundbreaking approach to detecting CD34+ cells without the need for cell staining, facilitating rapid CD34+ cell classification, even by individuals without prior expertise.

CD34 has spear-headed the field of basic research and clinical transplantation since the first reports of its expression on hematopoietic stem cells (HSCs). Expressed in mice, humans, rats and other species, CD34 has been used for more than 40 years as a hematopoietic stem and progenitor cell marker. It was later found that muscle satellite cells and epidermal precursors can also be identified with the aid of CD34. Despite the usefulness of CD34 as a marker of HSCs, its overall purpose in animal physiology has remained unclear. This review recaptures CD34 structure, evolutionary conservation, proposed functions, and role in lung inflammation, to describe current research findings and to provide guidance for future studies on CD34.

Wound healing is a complex and meticulously orchestrated process involving multiple phases and cellular interactions. This narrative review explores the intricate mechanisms behind wound healing, emphasizing the significance of cellular processes and molecular factors. The phases of wound healing are discussed, focusing on the roles of immune cells, growth factors, and extracellular matrix components. Cellular shape alterations driven by cytoskeletal modulation and the influence of the 'Formin' protein family are highlighted for their impact on wound healing processes. This review delves into the use of absorbable meshes in wound repair, discussing their categories and applications in different surgical scenarios. Interleukins (IL-2 and IL-6), CD31, CD34, platelet rich plasma (PRP), and adipose tissue-derived mesenchymal stem cells (ADSCs) are discussed in their respective roles in wound healing. The interactions between these factors and their potential synergies with absorbable meshes are explored, shedding light on how these combinations might enhance the healing process. Recent advances and challenges in the field are also presented, including insights into mesh integration, biocompatibility, infection prevention, and postoperative complications. This review underscores the importance of patient-specific factors and surgical techniques in optimizing mesh placement and healing outcomes. As wound healing remains a dynamic field, this narrative review provides a comprehensive overview of the current understanding and potential avenues for future research and clinical applications.

The glomerular basement membrane (GBM) is an important tissue structure in kidney function. It is the membrane through which filtrate and solutes must pass to reach the nephron tubules. This review focuses on the spatial location of the main extracellular matrix components of the GBM. It also attempts to explain this organization in terms of their synthesis, transport, and loss. The picture that emerges is that the collagen IV and laminin content of GBM are in a very slow dynamic disequilibrium, leading to GBM thickening with age, and in contrast, some heparan sulfate proteoglycans are in a dynamic equilibrium with a very rapid turnover (i.e. half-life measured in ~hours) and flow direction against the flow of filtrate. The highly rapid heparan sulfate turnover may serve several roles, including an unclogging mechanism for the GBM, compressive stiffness of the GBM fiber network, and/or enabling podocycte-endothelial crosstalk against the flow of filtrate.

The CD34 protein was identified almost four decades ago as a biomarker for hematopoietic stem cell progenitors. CD34 expression of these stem cells has been exploited for therapeutic purposes in various hematological disorders. In the last few decades, studies have revealed the presence of CD34 expression on other types of cells with non-hematopoietic origins, such as interstitial cells, endothelial cells, fibrocytes, and muscle satellite cells. Furthermore, CD34 expression may also be found on a variety of cancer stem cells. Nowadays, the molecular functions of this protein have been involved in a variety of cellular functions, such as enhancing proliferation and blocking cell differentiation, enhanced lymphocyte adhesion, and cell morphogenesis. Although a complete understanding of this transmembrane protein, including its developmental origins, its stem cell connections, and other functions, is yet to be achieved. In this paper, we aimed to carry out a systematic analysis of the structure, functions, and relationship with cancer stem cells of CD34 based on the literature overview.

We studied restoration of microvessels in the oral mucosa wound defects under a polymer piezoelectric membrane (group 2) and without it (group 1). The control group included animals with intact mucosa. On day 3, the expression of the vascular endothelial growth factor (VEGF) increased in all experimental groups, while the expression of CD34 increased only in group 2, which attested to intensive neoangiogenesis. On day 7, we observed a decrease in VEGF expression and an increase in CD34 expression that was more pronounced in group 2, which reflected the beginning of blood vessels maturation. More rapid formation and maturation of blood vessels in group 2 was confirmed by electron microscopy: on day 7, endothelial cells with mature organelles and signs of active transcapillary exchange were seen. On day 12, the immature blood vessels still predominated in group 1, while in group 2, the expression of angiogenesis markers decreased though remained above the control, which created prerequisites for the complete restoration of wound area vascularization in group 2. In group 1, the expression of VEGF and CD34 was significantly below the control, which attested to the development of poorly vascularized scar tissue.

Hematopoietic stem and progenitor cells (HSPCs) are desirable targets for gene therapy but are notoriously difficult to target and transfect. Existing viral vector-based delivery methods are not effective in HSPCs due to their cytotoxicity, limited HSPC uptake and lack of target specificity (tropism). Poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) are attractive, nontoxic carriers that can encapsulate various cargo and enable its controlled release. To engineer PLGA NP tropism for HSPCs, megakaryocyte (Mk) membranes, which possess HSPC-targeting moieties, were extracted and wrapped around PLGA NPs, producing MkNPs. In vitro, fluorophore-labeled MkNPs are internalized by HSPCs within 24 h and were selectively taken up by HSPCs versus other physiologically related cell types. Using membranes from megakaryoblastic CHRF-288 cells containing the same HSPC-targeting moieties as Mks, CHRF-wrapped NPs (CHNPs) loaded with small interfering RNA facilitated efficient RNA interference upon delivery to HSPCs in vitro. HSPC targeting was conserved in vivo, as poly(ethylene glycol)-PLGA NPs wrapped in CHRF membranes specifically targeted and were taken up by murine bone marrow HSPCs following intravenous administration. These findings suggest that MkNPs and CHNPs are effective and promising vehicles for targeted cargo delivery to HSPCs.

Myeloid sarcoma (MS) is a rare tumour comprising myeloid blasts occurring at an anatomical site other than the bone marrow. We sought to investigate both paediatric and adult patients with MS diagnosed at our institution and determine possible correlations among their clinicopathological, phenotypic, molecular and prognostic features.

This study retrospectively evaluated the data of 45 patients diagnosed with MS at Ege University Faculty of Medicine Hospital, Turkey, over a 17-year period.

The male-to-female ratio was 1.5:1, and the median age was 39.12 years. The most commonly involved sites were the skin, lymph nodes, soft tissues and bone. Immunohistochemically, CD68-KP1 was the most commonly expressed marker, followed by CD33, myeloperoxidase, CD117, lysozyme, CD68-PGM1 and CD34. Of the patients, 26 (57.7%) presented with de novo MS, 7 (15.5%) had simultaneous acute myeloid leukaemia and 12 (26.8%) had a previous history of haematological disorders. Kaplan-Meier survival analysis revealed that the 2-year and 5-year overall survival (OS) rates were 46.4% and 39.8%, respectively; the median OS duration was 11 months. Increasing age had a negative prognostic relationship with survival (p = 0.04). Chromosomal abnormalities were detected in approximately 6/10 (60%) of paediatric patients and 6/9 (66.7%) of adult patients. t(8;21)(q22;q22) translocation was identified in 20% of paediatric patients.

MS diagnosis is usually challenging; an expanded immunohistochemical panel should be used for an accurate diagnosis. Although MS generally has a poor prognosis, increasing age appears to be associated with a worse outcome.

CD34 is a cell surface antigen expressed in numerous stem/progenitor cells including hematopoietic stem cells (HSCs) and endothelial progenitor cells (EPCs), which are known to be rich sources of EPCs. Therefore, regenerative therapy using CD34⁺ cells has attracted interest for application in patients with various vascular, ischemic, and inflammatory diseases. CD34⁺ cells have recently been reported to improve therapeutic angiogenesis in a variety of diseases. Mechanistically, CD34⁺ cells are involved in both direct incorporation into the expanding vasculature and paracrine activity through angiogenesis, anti-inflammatory, immunomodulatory, and anti-apoptosis/fibrosis roles, which support the developing microvasculature. Preclinical, pilot, and clinical trials have well documented a track record of safety, practicality, and validity of CD34⁺ cell therapy in various diseases. However, the clinical application of CD34⁺ cell therapy has triggered scientific debates and controversies in last decade. This review covers all preexisting scientific literature and prepares an overview of the comprehensive biology of CD34⁺ cells as well as the preclinical/clinical details of CD34⁺ cell therapy for regenerative medicine.

Knowledge about the occurrence of processes such as proliferation, apoptosis and angiogenesis in healthy lung tissues with different bronchial epitheliums is limited, and further exploration can contribute to a better understanding of the physiological renewal of lung tissues. The processes mentioned above occur with the help of important tissue factors; therefore, the aim of the study was to determine the expression of markers Ki-67, nestin, CD34 and vascular endothelial growth factor (VEFG) and detect apoptotic cells in relatively healthy lung tissue.

Samples of relatively healthy lung tissue were obtained from 19 patients and divided into groups of patients with non-changed and patients with metaplastic bronchial epithelium. Tissue samples were examined by hematoxylin and eosin staining. Ki-67, nestin, VEGF and CD34-positive cells were detected by the immunohistochemistry method. Terminal deoxynucleotidyl transferase (TdT) dUTP nick-end labeling (TUNEL) assay was carried out to detect apoptotic cells. The number of positive structures was counted semi-quantitatively by microscopy.

Ki-67-positive cells were detected in only one case. An occasional to moderate number of nestin-positive structures was found in various tissues of relatively healthy lungs with different bronchial epitheliums. No apoptotic cells were seen in non-changed bronchial epithelium, compared with few apoptotic cells in metaplastic bronchial epithelium. Metaplastic bronchial epithelium contained more VEGF-positive cells than non-changed bronchial epithelium. Samples with non-changed, and metaplastic bronchial epithelium both contained a similar number of CD34-positive structures.

Proliferative activity and programmed cell death are not prominent events in normal lung tissue. A moderate number of nestin-positive cells in the alveolar epithelium and cartilage of bronchi with pseudostratified ciliated epithelium suggests a significant role of neuronal origin cells in these structures, to be intensified in metaplastic bronchial epithelium. A practically non-changed number of CD34-positive cells excludes any difference in stimulation of endothelial origin cells between lungs with different types of epithelium, while an increase in VEGF in structures with metaplastic epithelium suggests the presence/influence of tissue ischemia impact on possible development/maintenance of metaplasia.

Endothelial progenitor cells (EPCs): The name embodies years of research and clinical expectations, but where are we now? Do these cells really represent the El Dorado of regenerative medicine? Here, past and recent literature about this eclectic, still unknown and therefore fascinating cell population will be discussed. This review will take the reader through a temporal journey that, from the first discovery, will pass through years of research devoted to attempts at their definition and understanding their biology in health and disease, ending with the most recent evidence about their pathobiological role in cardiovascular disease and their recent applications in regenerative medicine.

Islet β-cell biomarkers can reflect changes in the number and function of islet β-cells in the prediabetes or early diabetes stage. CD34 is a commonly used stem cell biomarker; however, its expression and function in pancreatic islets remain unclear. In the present study, double immunofluorescence staining, proteomic bioinformatics analysis, and correlation analysis were used to explore the potential of CD34 as an islet β-cell biomarker. Bioinformatics analysis revealed that the amino acid sequence of CD34 was conserved among multiple species and abundantly expressed on mouse and human pancreatic tissues. Immunofluorescence demonstrated that in the control rat pancreas, CD34 was expressed on glucagon-labeled islet α-cells but not on insulin-labeled islet β-cells. Furthermore, the proportion of CD34-positive cells, which were also positive for glucagon, was significantly increased in alloxan-induced diabetes models. Statistical analysis revealed that the expression of CD34 was negatively correlated with the number of insulin-labeled islet β-cells during diabetes progression in dose-dependent fashion in alloxan-induced diabetes models. Furthermore, the results suggested that the transdifferentiation of islet β-cells into islet α-cells may occur in the process of diabetes. Thus, the present study demonstrated that CD34 is expressed on islet α-cells, and its number is linearly and negatively correlated with the number of islet β-cells, suggesting that CD34 can be used as a prospective biomarker for islet β-cells in the early diagnosis of diabetes. The study also suggests the transformation of β-cells to α-cells in diabetes which provide a potential to be applied towards diabetes mechanism research.

Chordoid meningioma (CM) is an infrequent histologic subtype of meningiomas. Owing to its low occurrence, this subtype has been rarely described. Our subject was to explore the clinical features, radiological characteristics, and prognostic factors of primary intracranial chordoid meningioma.

We reviewed the medical records and collected follow-up information of 34 cases who had been surgically treated and histologically diagnosed with CM at the Department of Neurosurgery, West-China Hospital of Sichuan University, from January 2009 to December 2021.

Among all 7,950 meningioma cases, the proportion of primary intracranial CM was 0.43% (34/7,950). The median diagnosis age was 47 (ranging from 12 to 74) and the gender ratio (male to female) was 2.1:1. For radiological features, heterogeneous enhancement, skull base, and ventricular localization, cystic degeneration and dural tail sign were common in CM cases. In treatment, gross total resection (GTR) was achieved in 22/34 cases (64.7%) and subtotal resection (STR) was achieved in 12/34 cases (35.3%). Further, 11/34 patients (32.4%) had received postoperative adjuvant radiotherapy (RT). The follow-up duration ranged from 4 to 157 months after operation. The progression rate was 20.7% (6/29) and the median of PFS was 38 months. By survival analysis, accepting adjuvant radiotherapy and achieving GTR were correlated with longer progression-free survival for prognosis.

CM is a rare subtype of meningiomas. In our series, it mainly involved adults and did not show a predilection for women compared with meningiomas in general. For a better prognosis, gross total resection and postoperative adjuvant radiotherapy are recommended. Nevertheless, due to the restriction of the series sample, patients lost for follow-up and inherent biases of a retrospective study, more cases and a shorter follow-up duration are needed for better management of chordoid meningioma.

The formation of a central lumen in the human epiblast is a critical step for development. However, because the lumen forms in the epiblast coincident with implantation, the molecular and cellular events of this early lumenogenesis process cannot be studied in vivo. Recent developments using new model systems have revealed insight into the underpinnings of epiblast formation. To provide an up-to-date comprehensive review of human epiblast lumenogenesis, we highlight recent findings from human and mouse models with an emphasis on new molecular understanding of a newly described apicosome compartment, a novel 'formative' state of pluripotency that coordinates with epiblast polarization, and new evidence about the physical and polarized trafficking mechanisms contributing to lumenogenesis.

PODXL, a protein that is dysregulated in multiple cancers, plays an important role in promoting cancer metastasis. In this study, we report that RNA editing promotes the inclusion of a PODXL alternative exon. The resulting edited PODXL long isoform is more prone to protease digestion and has the strongest effects on reducing cell migration and cisplatin chemoresistance among the three PODXL isoforms (short, unedited long, and edited long isoforms). Importantly, the editing level of the PODXL recoding site and the inclusion level of the PODXL alternative exon are strongly associated with overall patient survival in Kidney Renal Clear Cell Carcinoma (KIRC). Supported by significant enrichment of exonic RNA editing sites in alternatively spliced exons, we hypothesize that exonic RNA editing sites may enhance proteomic diversity through alternative splicing, in addition to amino acid changes, a previously under-appreciated aspect of RNA editing function.

Telocytes (TCs) are a vital constituent of interstitial tissue. They contribute to regulating cell function in heterotypic connections via direct contact or paracrine singling. Few studies mentioned intraepithelial TCs; however, they have been identified with scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In this study, we investigated the intraepithelial and interstitial TCs using immunohistochemistry (IHC) and TEM. TCs can be identified by their distinctive telopodes (TPs), which consist of podoms and podomere, using TEM and immunohistochemical staining with CD34, CD117, and VEGF antibodies. Intraepithelial TCs established heterocontact with the lamellar capillary and interstitial TCs connected with the blood vessel in lamina propria. Intraepithelial TCs established direct contact with epithelial cells, which formed the lymph space while interstitial TCs connected with the secondary vascular vessels. The study provides evidence for TCs' heterocontact with lamellar blood capillaries, the blood vessels, chloride cells, and immune cells, such as rodlet cells and lymphocytes. In conclusion, TCs have a role in regulating respiratory activities, maintaining osmotic pressure, modulating the immune response, and conducting immunosurveillance. RESEARCH HIGHLIGHTS: We investigated the intraepithelial and interstitial TCs using immunohistochemistry (IHC) and TEM. TCs can be identified by their distinctive telopodes (TPs), which consist of podoms and podomere, using TEM and immunohistochemical staining with CD34, CD117, and VEGF antibodies. Intraepithelial TCs established heterocontact with the lamellar capillary and interstitial TCs connected with the blood vessel in lamina propria.

Normal breast luminal epithelial progenitors have been implicated as cell of origin in basal-like breast cancer, but their anatomical localization remains understudied. Here, we combine collection under the microscope of organoids from reduction mammoplasties and single-cell mRNA sequencing (scRNA-seq) of FACS-sorted luminal epithelial cells with multicolor imaging to profile ducts and terminal duct lobular units (TDLUs) and compare them with breast cancer subtypes. Unsupervised clustering reveals eleven distinct clusters and a differentiation trajectory starting with keratin 15⁺ (K15⁺) progenitors enriched in ducts. Spatial mapping of luminal progenitors is confirmed at the protein level by staining with critical duct markers. Comparison of the gene expression profiles of normal luminal cells with those of breast cancer subtypes suggests a strong correlation between normal breast ductal progenitors and basal-like breast cancer. We propose that K15⁺ basal-like breast cancers originate in ductal progenitors, which emphasizes the importance of not only lineages but also cellular position within the ductal-lobular tree.

Podocalyxin (Podxl) is a CD34-related cell surface sialomucin that is normally highly expressed by adult vascular endothelia and kidney podocytes where it plays a key role in blocking adhesion. Importantly, it is also frequently upregulated on a wide array of human tumors and its expression often correlates with poor prognosis. We previously showed that, in xenograft studies, Podxl plays a key role in metastatic disease by making tumor initiating cells more mobile and invasive. Recently, we developed a novel antibody, PODO447, which shows exquisite specificity for a tumor-restricted glycoform of Podxl but does not react with Podxl expressed by normal adult tissue. Here we utilized an array of glycosylation defective cell lines to further define the PODO447 reactive epitope and reveal it as an O-linked core 1 glycan presented in the context of the Podxl peptide backbone. Further, we show that when coupled to monomethyl auristatin E (MMAE) toxic payload, PODO447 functions as a highly specific and effective antibody drug conjugate (ADC) in killing ovarian, pancreatic, glioblastoma and leukemia cell lines in vitro. Finally, we demonstrate PODO447-ADCs are highly effective in targeting human pancreatic and ovarian tumors in xenografted NSG and Nude mouse models. These data reveal PODO447-ADCs as exquisitely tumor-specific and highly efficacious immunotherapeutic reagents for the targeting of human tumors. Thus, PODO447 exhibits the appropriate characteristics for further development as a targeted clinical immunotherapy.