Bone regeneration is a complex and coordinated physiological process, and the different stages of this process have corresponding microenvironments to support cell development and physiological activities. However, biological scaffolds that provide different three-dimensional environments during different stages of bone regeneration are lacking. In this study, we report a novel composite scaffold (NPE@DCBM) inspired by the stages of bone regeneration; this scaffold was composed of a fibrin hydrogel loaded with nanoplatelet vesicles (NPVs), designated as NPE, and decellularized cancellous bone matrix (DCBM) microparticles. Initially, the NPE rapidly established a temporary microenvironment conducive to cell migration and angiogenesis. Subsequently, the DCBM simulated the molecular structure of bone and promoted new bone formation. In vitro, the NPVs regulated lipid metabolism in bone marrow mesenchymal stem cells (BMSCs), reprogramed the fate of BMSCs by activating the PI3K/AKT and MAPK/ERK positive feedback pathways, and increased BMSC functions, including proliferation, migration and proangiogenic potential. In vivo, NPV@DCBM accelerated bone tissue regeneration and repair. Initially, the NPE rapidly induced angiogenesis between DCBM microparticles, and subsequently, BMSCs differentiated into osteoblasts with DCBM microparticles at their core. In summary, the design of this composite scaffold that sequentially mimics different bone regeneration microenvironments may provide a promising strategy for bone regeneration, with clinical translational potential.

Previous work found a decrease in lysophosphatidylcholines (LPCs) in fibromyalgia (FM) serum, prompting the hypothesis that this decrease could be due to increased conversion of LPC to lysophosphatidic acid (LPA) through autotaxin (ATX). LPA has pronociceptive functions, and increased LPA levels could modulate FM pain.

This study quantified LPA levels in serum and lumbar cerebrospinal fluid (CSF) and serum ATX levels in FM patients, comparing with healthy controls (HCs), osteoarthritis (OA), degenerative disc disease (DDD) and lumbar disc herniation (LDH) patients.

We found increased serum LPA levels in FM and OA patients, with no changes in FM lumbar CSF. Unexpectedly, a positive correlation between serum LPA and conditioned pain modulation was observed in FM patients, while LPA levels were correlated with pain intensity and Knee Injury and Osteoarthritis Outcome Scores in OA. Serum ATX levels in FM patients were comparable to those in HC but correlated significantly with FM LPA levels (in one cohort), as well as with pain duration and the maximal weekly pain intensity.

This study suggests that increased LPA levels play distinct roles in FM and OA patients. In FM, LPA levels were linked to less impaired inhibitory pain pathways, while LPA levels in OA correlated with pain intensity and knee-related impairment. ATX levels in FM serum are associated with pain intensity and duration. These findings underscore the complex role of LPA and ATX in FM pathophysiology. Future studies are essential to clarify LPA's specific roles and to develop therapies.

This study provides novel insights into the role of LPA in FM and other chronic pain conditions. Although ATX levels were unchanged in FM, a positive correlation between serum ATX and LPA supports the role of ATX in LPA conversion. These findings suggest complex lipid dysregulation in FM, with LPA potentially modulating pain pathways. Further research is needed to clarify LPA's role and its potential as a biomarker or therapeutic target.

Dry eye is a multifactorial disease associated with impaired tear film homeostasis, damaging the ocular surface epithelium. Lysophosphatidic acid receptors (LPARs) are G-protein coupled receptors involved in Ca2+ and cAMP signaling via PLC and adenylyl cyclase activation. LPAR activation is involved in cell proliferation and wound healing in human corneal epithelial cells (HCECs) and in neuropathic pain. This study investigates the expression and functions of LPARs in ocular surface epithelial cells. Functional measurements of ocular surface potential difference (OSPD) were done in mice with topically applied, selective LPAR modulators. LPAR3 immunostaining was performed in mouse and human cornea and conjunctiva, and mouse lacrimal gland. LPAR-induced Ca2+ signaling was studied in primary and immortalized HCECs. The general LPAR agonist, linoleoyl LPA, and the LPAR3 selective agonist, 2S-OMPT, stimulated ocular surface Cl- secretion via Ca2+-activated Cl- channels (CaCCs). LPAR3 was expressed in the corneal and conjunctival epithelia of mice and humans, as well as in mouse lacrimal gland. Activation of LPAR and LPAR3 in HCECs transiently elevated intracellular Ca2+ through the Gq/PLC signaling pathway. LPAR3 agonists may potentially have therapeutic efficacy in ocular surface diseases, including dry eye disease.

Receptor-mediated cell activation frequently results in a plethora of effects, and interestingly, not all agonists that act on a given receptor activate all of those actions to the same extent. Biased agonism refers to this fact, i.e., the possibility to activate only a part of the receptor's signaling capabilities. It is worth mentioning that Biased Signaling is an integral concept that includes the system (organisms, isolated tissues, or cells), the individual receptor studied, and the ligands. It should be remembered that the system's genetic expression profile defines the type, abundance, and cellular localization of proteins that participate in signaling. This short review will be focused on G protein receptors, but biased signaling occurs in many other receptor types. Biased signaling can be related to the G proteins and β-arrestins available. Similarly, enzymes that catalyze receptor posttranslational modifications, such as phosphorylation, acylation, or ubiquitination, can play a role. G protein-coupled receptor signaling occurs at the plasma membrane, but it is well-established that endosomal signaling is a functional reality. Therefore, paying attention to cellular elements that participate in receptor endosomal traffic and destination (recycling to the plasma membrane/ degradation) is pertinent. There is still much to be known about these bias mechanisms, which are essential for basic knowledge of receptor drug action and for treating many pathological entities.

Lysophosphatidic acid (LPA) and the endocannabinoid system (ECS) are critical lipid signaling pathways involved in emotional regulation and behavior. Despite their interconnected roles and shared metabolic pathways, the specific contributions of LPA signaling through the LPA1 receptor to stress-related disorders remain poorly understood. This study investigates the effects of LPA1 receptor deficiency on emotional behavior and neurotransmitter-related gene expression, with a focus on sex-specific differences, using maLPA1-null mice of both sexes. We hypothesized LPA1 receptor loss disrupts the interplay between LPA and the endocannabinoid 2-arachidonoylglycerol (2-AG) signaling, resulting in distinct behavioral and molecular alterations. maLPA1-null mice exhibited increased anxiety-like behaviors and altered stress-coping responses compared to wild-type counterparts, with more pronounced effects observed in females. Female mice also displayed higher corticosterone levels, though no genotype-related differences were observed. Plasma analyses revealed elevated LPA levels in maLPA1-null mice, suggesting a compensatory mechanism, and reduced 2-AG levels, indicating impaired ECS signaling. Gene expression profiling in the amygdala and medial prefrontal cortex showed significant alterations in the gene expression of key components of LPA and 2-AG signaling pathways, as well as neuropeptide systems such as corticotropin-releasing hormone (CRH) and neuropeptide Y (NPY). Glutamatergic signaling components also exhibited sex-specific variations. These findings suggest that LPA1 receptor deficiency impacts behavioral response and disrupts sex-specific neurotransmitter signaling, emphasizing the importance of LPA-ECS crosstalk in emotional regulation. This study provides insights into the molecular mechanisms underlying stress-related disorders such as depression and anxiety, which may inform the development of sex-specific therapeutic approaches.

Fibroblast growth factor 23 (FGF23), primarily secreted by osteocytes and osteoblasts, is essential in regulating phosphate-calcium metabolism by inhibiting renal phosphate reabsorption and vitamin D synthesis. Acute kidney injury (AKI) is characterized by a rapid deterioration in renal function, accompanied by a significant increase in FGF23 levels, which contribute to its severity and progression. This study investigated the mechanistic roles of Gαq and Gα11 proteins, integral components of the lysophosphatidic acid (LPA) signaling pathway, in the regulation of FGF23 expression during AKI. Through targeted knockdown and pharmacological inhibition of Gαq and Gα11 in the osteoblastic MC3T3-E1 and osteocytic MLO-Y4 cells, we demonstrated that individual suppression of these G proteins had minimal impact on both basal and LPA-stimulated FGF23 levels. In contrast, concurrent knockdown significantly diminished FGF23 expression, implicating a synergistic role of Gαq and Gα11 in FGF23 regulation. This hypothesis was supported by using Gαq/11-specific inhibitors, YM-254890 and FR900359, which attenuated LPA-induced FGF23 upregulation. Our findings further elucidated the downstream signaling events, highlighting the involvement of PKC phosphorylation, intracellular calcium mobilization, and the MAPK/ERK1/2 pathway in mediating FGF23 expression. Moreover, in a folic acid-induced AKI mouse model, elevated FGF23 levels in bone, bone marrow, and serum were significantly reduced following YM-254890 administration, underscoring the potential of targeting Gαq/11 signaling in managing AKI-associated FGF23 dysregulation. This study not only advances our understanding of FGF23 regulation in renal injuries but also identifies Gαq/11 signaling modulation as a promising strategy to alleviate AKI severity and other disorders associated with dysregulated FGF23 levels.

Comparative studies using lysophosphatidic acid (LPA) and the synthetic agonist, oleoyl-methoxy glycerophosphothionate (OMPT), in cells expressing the LPA3 receptor revealed differences in the action of these agents. The possibility that more than one recognition cavity might exist for these ligands in the LPA3 receptor was considered. We performed agonist docking studies exploring the whole protein to obtain tridimensional details of the ligand-receptor interaction. Functional in cellulo experiments using mutants were also executed. Our work includes blind docking using the unrefined and refined proteins subjected to hot spot predictions. Distinct ligand protonation (charge -1 and -2) states were evaluated. One LPA recognition cavity is located near the lower surface of the receptor close to the cytoplasm (Lower Cavity). OMPT displayed an affinity for an additional identification cavity detected in the transmembrane and extracellular regions (Upper Cavity). Docking targeted to Trp102 favored binding of both ligands in the transmembrane domain near the extracellular areas (Upper Cavity), but the associating amino acids were not identical due to close sub-cavities. A receptor model was generated using AlphaFold3, which properly identified the transmembrane regions of the sequence and co-modeled the lipid environment accordingly. These two models independently generated (with and without the membrane) and adopted essentially the same conformation, validating the data obtained. A DeepSite analysis of the model predicted two main binding pockets, providing additional confidence in the predicted ligand-binding regions and support for the relevance of the docking-based interaction models. In addition, mutagenesis was performed of the amino acids of the two detected cavities. In the in cellulo studies, LPA action was much less affected by the distinct mutations than that of OMPT (which was almost abolished). Therefore, docking and functional data indicate the presence of distinct agonist binding cavities in the LPA3 receptor.

Autotaxin (ATX), a major source of the lipid mediator lysophosphatidic acid (LPA), plays a critical role in the pathogenesis and progression of pulmonary fibrosis. In this study, with the aim of developing novel ATX inhibitors with preferred lipophilicity, structure-based optimizations of PAT-409 were carried out, leading to the identification of two novel orally active ATX inhibitors, 4 and 29, with IC50 values of 1.5 nM and 1.08 nM, respectively. Both compounds demonstrated favorable physicochemical properties and desirable ADMET profiles. Notably, compounds 4 and 29 exhibited excellent in vitro metabolic stability (t1/2 > 170 min) and negligible cytotoxicity. Furthermore, oral administration of either compound 4 or 29 (60 mg/kg) exhibited comparable anti-pulmonary fibrosis effects to PAT-409 (60 mg/kg) in a bleomycin-induced pulmonary fibrosis mouse model, suggesting their potential as promising anti-pulmonary fibrosis agents for further development.

Autotaxin (ATX) has been recognized as an attractive target due to its hyperactivity in hydrolyzing lysophosphatidylcholine (LPC) into lysophosphatidic acid (LPA) throughout the initiation and progression of fibrotic diseases. Herein, a hydrophilic amide linker and sp3-rich bicyclic 4,5,6,7-tetrahydro-7H-pyrazolo[3,4-c]pyridin-7-one scaffold were employed to modify the lead compound PAT-409, followed by benzene ring fusion to generate novel tricyclic 4,5-dihydro-3H-pyrrolo[2,3-c]quinolin-4-one ATX inhibitors. Among them, the pyridine-2-carboxylic derivatives 45 and 46 demonstrated subnanomolar ATX inhibition (IC50 < 1 nM), with a favorable heart safety profile (hERG > 30 μM) and minimal fibroblast toxicity. Significantly, in bleomycin-induced pulmonary fibrosis mouse models, both compounds markedly improved respiratory function and reduced fibrotic lesions. Mechanistic studies revealed that 45 suppressed the TGF-β/Smad signaling pathway, downregulating α-smooth muscle actin (α-SMA) and extracellular matrix components (ECM). Overall, the identification of 45 and 46 for pulmonary fibrosis therapy provides a featured tricyclic scaffold for further development of novel ATX inhibitors.

Systemic sclerosis-associated interstitial lung disease (SSc-ILD) is a common complication of systemic sclerosis (SSc), contributing significantly to morbidity and mortality. We aim to bridge knowledge gaps, inform clinical practice, and identify future research directions in this rapidly evolving field.

This review provides a comprehensive analysis of the current understanding and emerging advances in the diagnosis, risk stratification, and treatment of SSc-ILD. High-resolution computed tomography (HRCT) and pulmonary function tests (PFTs) remain cornerstones of diagnosis, but limitations in sensitivity underscore the need for biomarkers such as Chemokine (C-C motif) Ligand 18 (CCL18), Krebs von den Lungen-6 (KL-6), Interleukin-6 (IL-6), and C-reactive protein (CRP) to enhance prognostic precision and treatment personalization. Therapeutic strategies emphasize immunosuppressants alongside antifibrotic agents. Emerging combination therapies and advanced modalities, including hematopoietic stem cell transplantation and chimeric antigen receptor T-cell therapy, show promise in refractory cases. Ongoing clinical trials exploring innovative targets highlight the evolving therapeutic landscape. The review emphasizes challenges in clinical trial design, advocating for adaptive and platform trial methodologies to address disease heterogeneity and enhance treatment sensitivity.

Advances in biomarkers, composite indices, and personalized therapeutic approaches are key to overcoming existing limitations and improving outcomes for patients with SSc-ILD.

In recent years, lysophospholipase autotaxin (ATX) has emerged as an attractive target for treating a variety of human diseases, including inflammation, neurodegeneration, angiogenesis, cancer, ocular and fibrotic diseases, among others. Starting with the quinazolinone hit structure 1, which emerged from a DNA-encoded library screen, the potent, non-Zn2+ binding ATX inhibitor 31 with good overall physicochemical properties has been developed. This compound demonstrated a sustained reduction of lysophosphatidic acid (LPA) in an in vivo rat experiment, qualifying it as a proof-of-concept compound for further mechanistic studies.

The integrity of corneal nerves is critical for ocular surface health, and damages can lead to Neurotrophic Keratopathy (NK). Despite the regenerative abilities of the peripheral nerve system (PNS), corneal nerve regeneration is often incomplete, and the underlying mechanisms are poorly understood. This study aims to identify potential factors that can enhance corneal nerve regeneration for NK treatment, with a focus on Lysophosphatidic acid (LPA). Thus, the effect of LPA and its underlying pathways in nerve regeneration is investigated in detail using in vitro mouse sensory neurons. To elucidate the impact of LPA as well as to reveal the responsible receptor, several functional assays as well as siRNA-based knock-down experiments were conducted. Additionally, possible changes in underlying pathways were investigated on mRNA levels. LPA-treated neurons significantly reduced fiber growth. However, LPAR2 knockdown neurons (Lpar2-KD) following LPA treatment showed a significant increase in fiber length. Additionally, LPA-treated neurons demonstrated enhanced levels of Lpar2 mRNA. On the other hand, nerve regeneration indicators such as Ngf, Gap-43, and Cdc42, along with LPA downstream signaling components like Pi3k and Ras, were elevated in Lpar2-KD neurons. In conclusion, this study elucidates the inhibitory effects of LPA on fiber outgrowth of sensory neurons. Furthermore, LPAR2 was identified as the responsible receptor for the LPA effect. Thus, Lpar2 knockdown might be a promising therapeutic approach to enhance neuronal regeneration in patients with NK.

The Smad transcription factors are well known for their role at the core of transforming growth factor-β (TGF-β) signalling. However, recent evidence shows that the Smad transcription factors play a vital role downstream of other classes of receptors including G protein-coupled receptors (GPCR). The versatility of Smad transcription factors originated from the two regions that can be differently activated by the TGF-β receptor superfamily or through the recruitment of intracellular kinases stimulated by other receptors classes such as GPCRs. The classic GPCR signalling cascade is further expanded to conditional adoption of the Smad transcription factor under the stimulation of Akt, demonstrating the unique involvement of the Smad transcription factor in GPCR signalling pathways in disease environments. In this review, we provide a summary of the signalling pathways of the Smad transcription factors as an important downstream mediator of GPCRs, presenting exciting opportunities for discovering new therapeutic targets for diseases.

Colorectal cancer (CRC) remains a principal contributor to oncological mortality worldwide, with chronic inflammation serving as a fundamental driver of its pathogenesis. Protease-activated receptor-2 (PAR-2), a G-protein-coupled receptor, orchestrates inflammation-driven tumorigenesis by potentiating NF-κB and Wnt/β-catenin signaling, thereby fostering epithelial-mesenchymal transition (EMT), immune evasion, and therapeutic resistance. Despite its pathological significance, targeted modulation of PAR-2 remains an underexplored avenue in CRC therapeutics. Oleocanthal (OC), a phenolic constituent of extra virgin olive oil, is recognized for its potent anti-inflammatory and anti-cancer properties; however, its regulatory influence on PAR-2 signaling in CRC is yet to be elucidated. This study interrogates the impact of OC on PAR-2-mediated inflammatory cascades using HT-29 and Caco-2 CRC cell lines subjected to lipopolysaccharide (LPS)-induced activation of PAR-2. Expression levels of PAR-2 and TNF-α were quantified through Western blotting and RT-PCR, while ELISA assessed TNF-α secretion. Intracellular calcium flux, a pivotal modulator of PAR-2-driven oncogenic inflammation, was evaluated via Fluo-4 calcium assays. LPS markedly elevated PAR-2 expression at both mRNA and protein levels in CRC cells (p < 0.01, one-way ANOVA). OC administration (20-150 μg/mL) elicited a dose-dependent suppression of PAR-2, with maximal inhibition at 100-150 μg/mL (p < 0.001, Tukey's post hoc test). Concomitant reductions in TNF-α transcription (p < 0.01) and secretion (p < 0.001) were observed, corroborating the anti-inflammatory efficacy of OC. Additionally, OC ameliorated LPS-induced calcium dysregulation, restoring intracellular calcium homeostasis in a concentration-dependent manner (p < 0.01). Crucially, OC exhibited selectivity for PAR-2, leaving PAR-1 expression unaltered (p > 0.05), underscoring its precision as a therapeutic agent. These findings position OC as a selective modulator of PAR-2-driven inflammation in CRC, disrupting the pro-tumorigenic microenvironment through attenuation of TNF-α secretion, calcium dysregulation, and oncogenic signaling pathways. This study furnishes mechanistic insights into OC's potential as a nutraceutical intervention in inflammation-associated CRC. Given the variability in OC bioavailability and content in commercial olive oil, future investigations should delineate optimal dosing strategies and in vivo efficacy to advance its translational potential in CRC therapy.

The lysophosphatidic acid receptor 1 (LPAR1) is one of the six cognate G protein-coupled receptors of the bioactive, growth factor-like phospholipid lysophosphatidic acid (LPA). LPAR1 is widely expressed in different cell types and mediates many LPA effects. LPAR1 has been implicated in several chronic inflammatory diseases, and especially pulmonary fibrosis, where it has been established as a promising therapeutic target. Herein, we present the generation of several Lpar1 mouse strains through genetic recombination. These strains include an initial versatile Lpar1 strain (tm1a) from which three other strains derive: an Lpar1 reporter knockout strain (tm1b) where LacZ has replaced exon 3 of Lpar1; a "floxed" Lpar1 strain (tm1c), where exon 3 is flanked by two loxP sites allowing conditional, cell-specific Lpar1 inactivation; and a complete KO strain of Lpar1 (tm1d), where exon 3 has been deleted. The generated strains are novel genetic tools, that can have various applications in studying LPA-LPAR1 signaling and its role in normal physiology and disease.

By inhibiting the conversion of lysophosphatidylcholine into lysophosphatidic acid, a process pivotal to tumor progression, the autotaxin (ATX) inhibitor PF-8380 offers a new anticancer therapeutic strategy, distinct from the action mechanism of sorafenib. This study explored the potential anticancer effects of the PF-8380 on hepatocellular carcinoma (HCC) cells, especially sorafenib-resistant strains. The investigation included both in vitro and in vivo experiments to evaluate the impact of PF-8380 treatment on epithelial-mesenchymal transition (EMT) and autophagy markers. An orthotopic HCC model served as the in vivo platform. PF-8380 showed a significant reduction in cell viability in both sorafenib-susceptible and resistant HCC cells. It effectively altered EMT by increasing E-cadherin and reducing Snail levels, and inhibited autophagy, as indicated by changes in LC3 and p62 markers. These effects were consistently observed in the orthotopic HCC mouse model, reinforcing PF-8380's potential as a dual inhibitor of EMT and autophagy in HCC treatment. Our research indicates that PF-8380 could provide substantial therapeutic benefits in the treatment of HCC, even in cases resistant to sorafenib, primarily by suppressing both EMT and autophagy processes.

Sarcoglycanopathies are muscle dystrophies caused by mutations in the genes encoding sarcoglycans (α, β, γ, and δ) that can destabilize the dystrophin-associated glycoprotein complex at the sarcolemma, leaving muscle fibers vulnerable to damage after contraction, followed by inflammatory and fibrotic responses and resulting in muscle weakness and atrophy. Two signaling pathways have been implicated in fibrosis and inflammation in various tissues: autotaxin/lysophosphatidic acid (ATX-LPA) and yes-associated protein 1/transcriptional co-activator with PDZ-binding motif (YAP/TAZ). LPA, synthesized by ATX, can act as a pleiotropic molecule due to its multiple receptors. Two Hippo pathway effectors, YAP/TAZ, can be dephosphorylated by LPA and translocated to the nucleus. They induce several target genes, such as CCN2/CTGF, involved in fibrosis and inflammation. However, no detailed characterization of these processes or whether these pathways change early in the development of sarcoglycanopathy has been evaluated in skeletal muscle.

Using the δ-sarcoglycan knockout mouse model (Sgcd-/-), we investigated components of these pathways, inflammatory and fibrotic markers, and contractile properties of different skeletal muscles (triceps-TR, gastrocnemius-GST, diaphragm-DFG, tibialis anterior-TA, and extensor digitorum longus-EDL) at one and two months of age.

We found that Sgcd-/- mice show early dystrophic features (fiber damage/necrosis, centrally nucleated fibers, inflammatory infiltrate, and regenerated fibers) followed by later fiber size reduction in TR, GST, and DFG. These changes are concomitant with an early inflammatory and fibrotic response in these muscles. Sgcd-/- mice also have early impaired force generation in the TA and EDL, and resistance to mechanical damage in the EDL. In addition, an early dysregulation of the ATX-LPA axis and the YAP/TAZ signaling pathway in the TR, GST, and DFG was observed in these mice.

The ATX-LPA axis and the YAP/TAZ signaling pathway, which are involved in inflammation and fibrosis, are dysregulated in skeletal muscle from an early age in Sgcd-/- mice. These changes are concomitant with a fibrotic and inflammatory response in these mice. Unraveling the role of the LPA axis and YAP/TAZ in sarcoglycanopathy holds great promise for improving our understanding of disease pathogenesis and identifying novel therapeutic targets for this currently incurable group of muscle disorders.

Recent interest has focused on the role of Ca2+ in regulating health problems, including cardiovascular disease and colorectal cancer. The inverse correlation between colon cancer and serum Ca2+ underlines the importance of understanding intracellular Ca2+ dynamics. Studies are also evaluating the contributions of abnormalities in Ca²⁺ homeostasis and intracellular dysfunction to the pathogenesis of metabolic syndrome as a precursor of cardiovascular disease. In this study, we investigated the changes of Ca2+ dynamics and ginsenoside Rb1 (Rb1)-induced recovery in two vascular cell lines exposed to palmitic acid (PA), the most abundant active ingredient in palm oil. The mechanism underlying the Rb1-induced recovery was examined in a store operated Ca2+ entry model by Ca2+ store depletion. PA reduced the Ca2+ influx in both EA.hy926 (EA) and MOVAS cells, and this change was restored by Rb1. In EA cells, the Rb1-induced restoration was abolished by U73122 or 2-APB. In MOVAS cells, meanwhile, the effect of Rb1 was abolished by FIPI, U73122 and U73343. Under normal conditions, Rb1 itself altered phospholipid signaling (PLC in EA cells and PLD in MOVAS cells), but did not affect Ca2+ homeostasis. These differences resulted in differences in downstream actions, as KB-R7943 and nifedipine inhibited Rb1-mediated Ca2+ influx recovery only in MOVAS cells. In conclusion, Rb1 rescues the PA-induced Ca2+ influx by appropriately activating PLC in EA cells and PLD in MOVAS cells. This demonstrates that Ca2+ dynamics are elaborately regulated via intracellular Ca2+ signaling networks, suggesting a potential strategy for maintaining vascular Ca2+ homeostasis in hyperlipidemic environments.

Pulmonary fibrosis encompasses different chronic interstitial lung diseases, and the predominant form, idiopathic pulmonary fibrosis, remains to have a poor prognosis despite 2 approved therapies. Although the exact pathobiological mechanisms are still incompletely understood, epithelial injury and aberrant wound healing responses contribute to the gradual change in lung architecture and functional impairment. Lysophosphatidic acid (LPA)-induced lysophosphatidic receptor 1 (LPA1) signaling was proposed to be a driver of lung fibrosis, and LPA1 antagonists have shown promising antifibrotic profiles in early clinical development. The novel, potent, and selective LPA1 antagonist, ACT-1016-0707, displayed insurmountable LPA1 antagonism in vitro with slow off-rate kinetics, leading to efficient inhibition of LPA1 signaling even in presence of high concentrations of LPA. This binding property translated into potent and highly efficient prevention of LPA-induced skin vascular leakage by ACT-1016-0707 in vivo, differentiating the compound from surmountable LPA1 antagonists. Furthermore, ACT-1016-0707 attenuated proinflammatory and profibrotic signaling in different lung fibrosis models in vitro and in the bleomycin-induced lung fibrosis model in vivo. Based on these data, ACT-1016-0707 shows potential as best-in-class LPA1 antagonist for treatment of fibrotic diseases. SIGNIFICANCE STATEMENT: ACT-1016-0707 is a potent, selective, and insurmountable lysophosphatidic receptor 1 (LPA1) antagonist demonstrating robust antifibrotic and anti-inflammatory activity in different lung fibrosis models in vitro and in vivo. This study is the first to demonstrate functional in vivo evidence of insurmountable LPA1 antagonist superiority by side-by-side comparison with surmountable LPA1 antagonists in highly controlled conditions, suggesting potential for ACT-1016-0707 as best-in-class LPA1 antagonist for treatment of fibrotic diseases.

Lipid phosphate phosphatase 3 (LPP3) is a membrane-bound enzyme that hydrolyzes lipid phosphates including the bioactive lipid, lysophosphatidic acid (LPA). Elevated circulating LPA production and cellular LPA signaling are implicated in obesity-induced metabolic and cardiac dysfunction. Deletion of LPP3 in the cardiomyocyte increases circulating LPA levels and causes heart failure and mitochondrial dysfunction in mice. To examine the influence of LPP3 modulation in the cardiomyocyte on obesity-induced cardiomyopathy, we generated mice with cardiomyocyte-specific LPP3 overexpression (LPP3OE mice) driven by the α myosin heavy chain promoter. Female and male control (LPP3FL) and LPP3OE mice were fed low-fat diet (LFD) or high-fat diet (HFD) for up to 22-23 wk, followed by the analysis of glucose homeostasis, cardiac function, plasma LPA levels, and mitochondrial respiration in cardiac myofibers. On LFD, both female and male LPP3OE mice had markedly reduced plasma LPA levels and increased pyruvate-linked respiration when compared with LPP3FL mice while body weight and global insulin sensitivity were similar between genotypes. Following HFD feeding, female LPP3OE mice were protected from increased plasma LPA levels, excess adiposity, systemic insulin resistance, and systolic and diastolic cardiac dysfunction compared with LPP3FL mice. Female LPP3OE mice also maintained elevated cardiac pyruvate-linked mitochondrial respiration following HFD feeding while mitochondrial respiration was similar between genotypes in HFD-fed male mice. This study suggests that cardiomyocyte-specific LPP3 upregulation protects particularly female mice from HFD-induced metabolic dysfunction and cardiomyopathy.NEW & NOTEWORTHY Lipid phosphate phosphatase 3 (LPP3) hydrolyzes bioactive lipids including lysophosphatidic acid (LPA), elevated levels of which are implicated in obesity-induced metabolic and cardiac dysfunction. We show that cardiac-specific overexpression of LPP3 lowers plasma LPA levels, blunts LPA signaling in cardiomyocytes, and increases pyruvate-linked mitochondrial respiration in the heart at baseline in both male and female mice. In female mice, LPP3 overexpression also protects from high-fat diet-induced obesity, insulin resistance, and cardiac dysfunction.

Ependymal cells line the wall of cerebral ventricles and ensure the unidirectional cerebrospinal fluid (CSF) flow by beating their motile cilia coordinately. The ependymal denudation or ciliary dysfunction causes hydrocephalus. Here, we report that the deficiency of regulator of G-protein signaling 22 (RGS22) results in severe congenital hydrocephalus in both mice and rats. Interestingly, RGS22 is specifically expressed in ependymal cells within the brain. Using conditional knock-out mice, we further demonstrate that the deletion of Rgs22 exclusively in nervous system is sufficient to induce hydrocephalus. Mechanistically, we show that Rgs22 deficiency leads to the ependymal denudation and impaired ciliogenesis. This phenomenon can be attributed to the excessive activation of lysophosphatidic acid receptor (LPAR) signaling under Rgs22-/- condition, as the LPAR blockade effectively alleviates hydrocephalus in Rgs22-/- rats. Therefore, our findings unveil a previously unrecognized role of RGS22 in the central nervous system, and present RGS22 as a potential diagnostic and therapeutic target for hydrocephalus.

Ginseng, a traditional herbal medicine with a long history of use, is known to support human health, particularly by influencing brain function. Recent studies have identified gintonin, a lysophosphatidic acid (LPA) receptor ligand derived from ginseng, as a key bioactive. However, the specific LPA receptor subtypes targeted by gintonin in the human brain to exert its anti-Alzheimer's (AD) effects remain unclear. This study aimed to elucidate the LPA receptor subtype targeted by gintonin in the human cortex. Using a fluorescent gintonin conjugate, we investigated receptor binding in cortical samples from healthy individuals (n = 4) and AD patients (n = 4). Our results demonstrated that fluorescent gintonin selectively binds to human cortical neurons rather than glial cells and that gintonin-binding sites are co-localized with the LPA4 receptor subtype. Furthermore, the expression of LPA4 receptors was significantly reduced in the cortical neurons of AD patients. These results suggest that the LPA4 receptor may serve as a novel histopathological marker for AD and represent a promising therapeutic target for gintonin-based prevention and treatment strategies.

Pulmonary fibrosis (PF) is a progressive, fatal lung disease lacking effective treatments. Autotaxin (ATX) plays a crucial role in exacerbating inflammation and fibrosis, making it a promising target for fibrosis therapies. Herein, starting from PAT-409 (Cudetaxestat), a series of novel ATX inhibitors bearing 1H-indole-3-carboxamide, 4,5,6,7-tetrahydro-7H-pyrazolo[3,4-c]pyridin-7-one, or 4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridine cores were designed based on the structure of ATX hydrophobic tunnel. The optimal 31 and 35 inhibited ATX with IC50 values of 2.8 and 0.7 nM, respectively. In a bleomycin-induced mouse PF model, both compounds significantly reduced fibrosis by regulating the TGF-β/Smad signaling pathway and downregulating collagen deposition. Furthermore, 35 exhibited both negligibly low hERG channel inhibition (IC50 > 30 μM) and remarkable microsomal stability. Notably, 35 was characterized by favorable pharmacokinetic properties (F = 69.5%) and excellent safety in vivo. Overall, 35 turned out to be a well-characterized potent and safe ATX inhibitor warranting further investigation for the treatment of PF.

-2,3,5,4'-tetrahydroxystilbene-2-O-β-D-glucoside (THSG) is a bioactive component in the Chinese herb Polygonum multiflorum, recognized for its anti-inflammatory and lipid-lowering properties. Human dental pulp stem cells (hDPSCs) have excellent capabilities in tooth regeneration, wound healing, and neural repair. The exosomes (Exo) released by hDPSCs contain bioactive molecules that influence cell proliferation, differentiation, and immune responses. Therefore, we aimed to unveil the potential of THSG-Exo and evaluate its regenerative capabilities through the in vitro experiment and rat bone defect model.

The effects of hDPSC-derived exosomes, with or without THSG treatment, on repair and bone regeneration were evaluated through in vitro and in vivo studies. Finally, we conducted a proteomic analysis to meticulously compare the compositional contents of the two types of exosomes.

In vitro data showed that 10 and 100 μM THSG-Exo enhanced cell proliferation and osteogenic differentiation, reducing wound size to 40 % of its original size. In our maxillary bone defect rat model, THSG-Exo significantly increased bone volume, trabecular thickness, and bone density in the bone defect area. In addition, proteomic analysis of THSG-Exo revealed diverse proteins linked to bone differentiation and tissue repair, including bone morphogenetic protein-1 (BMP-1) and tumor necrosis factor (TNF)-α-stimulated gene 6 (TNFAIP6). Our searches in functional databases revealed that THSG-Exo is involved in numerous biological pathways.

THSG-Exo enhanced cell proliferation, wound healing, and osteogenesis in vitro, while also expediting tissue repair and bone regeneration in vivo. The protein diversity of THSG-Exo contributes significant value in both basic and regenerative medicine.

Transmembrane-6 superfamily member 2 (TM6SF2) regulates hepatic fat metabolism and is associated with metabolic dysfunction-associated steatohepatitis (MASH). TM6SF2 genetic variants are associated with steatotic liver disease. The pathogenesis of MASH involves genetic factors and gut microbiota alteration, yet the role of host-microbe interactions in MASH development remains unclear. Here, we discover that mice with intestinal epithelial cell-specific knockout of Tm6sf2 (Tm6sf2ΔIEC) develop MASH, accompanied by impaired intestinal barrier and microbial dysbiosis. Transplanting stools from Tm6sf2ΔIEC mice induces steatohepatitis in germ-free recipient mice, whereas MASH is alleviated in Tm6sf2ΔIEC mice co-housed with wild-type mice. Mechanistically, Tm6sf2-deficient intestinal cells secrete more free fatty acids by interacting with fatty acid-binding protein 5 to induce intestinal barrier dysfunction, enrichment of pathobionts, and elevation of lysophosphatidic acid (LPA) levels. LPA is translocated from the gut to the liver, contributing to lipid accumulation and inflammation. Pharmacological inhibition of the LPA receptor suppresses MASH in both Tm6sf2ΔIEC and wild-type mice. Hence, modulating microbiota or blocking the LPA receptor is a potential therapeutic strategy in TM6SF2 deficiency-induced MASH.

Interstitial lung disease (ILD) is a clinical term that refers to a diverse group of non-neoplastic lung diseases. This group includes idiopathic and secondary pulmonary entities that are often associated with progressive pulmonary fibrosis. Currently, therapeutic approaches based on specific structural targeting of pulmonary fibrosis are limited to nintedanib and pirfenidone, which can only slow down disease progression leading to a lower mortality rate. Lung transplantation is currently the only available curative treatment, but it is associated with high perioperative mortality. The pulmonary vasculature plays a central role in physiological lung function, and vascular remodelling is considered a hallmark of the initiation and progression of pulmonary fibrosis. Different patterns of pulmonary fibrosis commonly exhibit detectable pathological features such as morphomolecular changes, including intussusceptive and sprouting angiogenesis, vascular morphometry, broncho-systemic anastomoses, and aberrant angiogenesis-related gene expression patterns. Dynamic cellular interactions within the fibrovascular interface, such as endothelial activation and endothelial-mesenchymal transition, are also observed. This review aims to summarise the current clinical, radiological and pathological diagnostic algorithm for different ILDs, including usual interstitial pneumonia/idiopathic pulmonary fibrosis, non-specific interstitial pneumonia, alveolar fibroelastosis/pleuroparenchymal fibroelastosis, hypersensitivity pneumonitis, systemic sclerosis-related ILD and coronavirus disease 2019 injury. It emphasises an interdisciplinary clinicopathological perspective. Additionally, the review covers current therapeutic strategies and knowledge about associated vascular abnormalities.

Endometrosis (chronic degenerative endometritis) results in morphological changes in the equine endometrium and impairs its secretory function. However, the effect of this condition on the myometrium remains unclear. Lysophosphatidic acid (LPA) may affect female reproductive function and embryo transport by influencing uterine contractility through its receptors (LPARs). The objective of this study was to determine myometrial LPAR1-6 mRNA transcription, and the effects of LPA on myometrial contractions in mares with endometrosis during the mid-luteal and follicular phases of the estrous cycle.

A reduction in myometrial LPAR1 mRNA transcription was observed in mares with endometrosis during the mid-luteal phase, in comparison to those with category I endometria (P < 0.05). While, upregulation of myometrial LPAR3 or LPAR6 mRNA transcription was observed in mares with category III or IIB endometria; respectively (P < 0.05). An increase in myometrial LPAR1, LPAR3 and LPAR5 mRNA transcription was observed during the follicular phase in mares with category IIA endometrium in comparison to their expression in category I endometrium (P < 0.05). During endometrosis progression LPA reduced the force of myometrial contractions in both phases of the estrous cycle (P < 0.05). However, in mares with category IIA endometrium during the follicular phase, LPA was found to increase the force of contraction of myometrial strips in comparison to mares with category I endometrium (P < 0.01).

In the course of endometrosis in mares, a disruption in the myometrial mRNA transcription of LPARs has been observed. This is the first study to examine the impact of LPA on myometrial contractility at diffrent stage of endometrosis. However, it is essential to consider that multiple factors may contribute to this process. Alternations in contractile activity and changes in myometrial LPARs mRNA transcription may indicate impaired LPA-signaling mechanisms in equine myometrium during endometrosis.

Diabetic nephropathy (DN) is a serious consequence of diabetes that can develop through the lysophosphatidic acid axis. The purpose of this study was to determine whether the antidiabetic drug liraglutide can slow the development of diabetic kidney damage by altering the lysophosphatidic acid axis via KLF5.

Wistar albino rats were divided into nondiabetic and diabetic rats (resulting from an intraperitoneal streptozotocin dose of 30 mg/kg and a high-fat diet). These rats were further divided into four groups: nondiabetic control, liraglutide-treated nondiabetic, diabetic control, and liraglutide-treated diabetic. The nondiabetic and diabetic control groups received normal saline for 42 days, while the liraglutide-treated nondiabetic and diabetic groups received normal saline for 21 days, followed by a subcutaneous dose of liraglutide (200 μg/kg/day) for 21 days. Subsequently, serum levels of DN biomarkers were evaluated, and kidney tissues were histologically examined. The protein expression of PCNA, autotaxin, and KLF5 was detected.

Liraglutide treatment in diabetic rats decreased DN biomarkers, histological abnormalities in kidney tissues, and the protein expression of PCNA, autotaxin, and KLF5.

Liraglutide can slow the progression of DN by modulating KLF5-related lysophosphatidic acid axis. Thus, liraglutide may be an effective treatment for preventing or mitigating diabetes-related kidney damage.

Lysophosphatidic acid (LPA) is a bioactive lipid that is mainly produced by the secreted lysophospholipase D, autotaxin (ATX), and signals through at least six G protein-coupled receptors (LPA1-6). Extracellular LPA is degraded through lipid phosphate phosphatases (LPP1, LPP2, and LPP3) at the plasmamembrane, terminating LPA receptor signaling. The ATX-LPA-LPP3 pathway is critically involved in a wide range of physiological processes, including cell survival, migration, proliferation, angiogenesis, and organismal development. Similarly, dysregulation of this pathway has been linked to many pathological processes, including cardiovascular disease. This review summarizes and interprets current literature examining the regulation and role of the ATX-LPA-LPP3 axis in heart disease. Specifically, the contribution of altered LPA metabolism via ATX and LPP3 and resulting changes to LPA receptor signaling in obesity cardiomyopathy, cardiac mitochondrial dysfunction, myocardial infarction/ischemia-reperfusion injury, hypertrophic cardiomyopathy, and aortic valve stenosis is discussed.

Lysophosphatidic acid receptor 1 (LPA1) is one of the G protein-coupled receptors activated by the lipid mediator, lysophosphatidic acid (LPA). LPA1 is associated with a variety of diseases, and LPA1 agonists have potential therapeutic value for treating obesity and depression. Although potent nonlipid LPA1 agonists have recently been identified, the mechanisms of nonlipid molecule-mediated LPA1 activation remain unclear. Here, we report a cryo-electron microscopy structure of the human LPA1-Gi complex bound to a nonlipid basic agonist, CpY, which has 30-fold higher agonistic activity as compared with LPA. Structural comparisons of LPA1 with other lipid GPCRs revealed that the negative charge in the characteristic binding pocket of LPA1 allows the selective recognition of CpY, which lacks a polar head. In addition, our structure show that the ethyl group of CpY directly pushes W2716.48 to fix the active conformation. Endogenous LPA lacks these chemical features, which thus represent the crucial elements of nonlipid agonists that potently activate LPA1. This study provides detailed mechanistic insights into the ligand recognition and activation of LPA1 by nonlipid agonists, expanding the scope for drug development targeting the LPA receptors.

This focused review highlights the importance of yes-associated protein (YAP)/transcriptional coactivator with PDZ binding motif (TAZ) mechanosignaling in human trabecular meshwork and Schlemm's canal cells in response to glaucoma-associated extracellular matrix stiffening and cyclic mechanical stretch, as well as biochemical pathway modulators (with signaling crosstalk) including transforming growth factor beta 2, glucocorticoids, Wnt, lysophosphatidic acid, vascular endothelial growth factor, and oxidative stress. We provide a comprehensive overview of relevant literature from the last decade, highlight intriguing research avenues with translational potential, and close with an outlook on future directions.

Autotaxin (ATX) is an adipokine known to affect energy metabolism and lipid homeostasis. We aimed to evaluate serum ATX levels in metabolic-associated fatty liver disease (MAFLD) and other metabolic disorders in postmenopausal women.

Postmenopausal women who received an annual health examination were included. The metabolic and demographic characteristics of the subjects were collected, including age, gender, weight, height, blood pressure, and biochemical parameters. Serum ATX level was determined by ELISA.

This cross-sectional includes 20 postmenopausal women and 20 age-paired healthy controls. MAFLD patients showed significant metabolic disturbance presented with increased body mass index (BMI), blood pressure (p < 0.001) and decreased high-density lipoprotein cholesterol (p < 0.05), as well as liver injury companied by elevated ALT (p < 0.05). Serum ATX levels were statistically higher in MAFLD (253.1 ± 52.1 vs. 202.2 ± 53.2 ng/mL; p < 0.01) and positively correlated with ALT (p < 0.001), γ-glutamyltransferase and BMI (p < 0.01), SBP and TG (p < 0.05). Higher ATX group demonstrated worsen metabolic states with greater proportion of MAFLD, higher BMI (p < 0.01), and ALT (p < 0.05). Logistic regression analysis revealed that serum ATX levels would positively independently predicted MAFLD (OR 1.049, 95% CI: 1.001-1.098, p < 0.05) with AUC of 0.763. Serum level of ATX is significantly elevated in hyperuricemia group (257.3 ± 60.9 vs. 214.5 ± 49.4 ng/mL; p < 0.05) and positively correlated with uric acid level (p < 0.01). Serum ATX would also act as diagnosing parameter of hyperuricemia with AUC of 0.706.

Among postmenopausal women, serum ATX level is significantly elevated in MAFLD and related to multiple metabolic characteristics, especially hyperuricemia, which would thus serve as a potential noninvasive biomarker as well as a therapeutic target.

We addressed fundamental questions about the influence of metabolites on the development of Diabetic retinopathy (DR), and explored the related pathological mechanism. Genome-wide association study (GWAS) database data for metabolites and DR were used to perform Mendelian randomization (MR) studies. The inverse variance weighting (IVW) was chosen as the primary analysis method. Sensitivity analysis was conducted using MR-PRESSO, leave-one-out and Cochran's Q test. Confounding factors were eliminated to ensure robustness. We also conducted metabolic pathway analysis. In vivo experimental validation was conducted using Sprague Dawley rats. The serum metabolites of the DR group rats and normal group rats were examined to evaluate the MR results. The screen identified eighteen metabolites associated with DR risk, twelve of which were known components. Seven metabolites were positively correlated with DR risk, while five could reduce it. Eight metabolites associated with proliferative DR (PDR) risk were identified, four of which are known components. Three of these were positively associated with PDR risk and one metabolite reduced PDR risk. Additionally, two possible metabolic pathways involved in the biological mechanism of DR were identified. The ELISA results showed that the serum levels of isoleucine and 4-HPA were significantly increased in DR rats, while the level of inosine was decreased. This study offers novel insights into the biological mechanisms underlying DR. Metabolites that are causally linked to DR may serve as promising biomarkers and therapeutic targets.

In this study, we aimed to explore the mechanism by which resveratrol promotes cisplatin-induced death of HepG2 cells and to provide a potential strategy for resveratrol in the treatment of cancer.

HepG2 cells were exposed to a range of drug concentrations for 24 h: resveratrol (2.5 μg/mL [10.95 μM], 5 μg/mL [21.91 μM], 10 μg/mL [43.81 μM], 20 μg/mL [87.62 μM], 40 μg/mL [175.25 μM], and 80 μg/mL [350.50 μM]), cisplatin (0.625 μg/mL [2.08 μM], 1.25 μg/mL [4.17 μM], 2.5 μg/mL [8.33 μM], 4.5 μg/mL [15.00 μM], and 10 μg/mL [33.33 μM]), 24 μg/mL (105.15 μM) resveratrol + 9 μg/mL (30.00 μM) cisplatin, and 12 μg/mL (52.57 μM) resveratrol + 4.5 μg/mL (15.00 μM) cisplatin. The interaction of two drugs was evaluated by coefficient of drug interaction (CDI), which was based on the Pharmacological Additivity model. The MTT 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to detect the effect of different concentrations of drugs on cell viability, while transcriptome sequencing was used to identify pathways associated with higher gene enrichment. Synchrotron radiation FTIR microspectroscopy experiments and data analysis were conducted to obtain detailed spectral information. The second-derivative spectra were calculated using the Savitzky-Golay algorithm. Single-cell infrared spectral absorption matrices were constructed to analyze the spectral characteristics of individual cells. The Euclidean distance between cells was calculated to assess their spectral similarity. The cell-to-cell Euclidean distance was computed to evaluate the spatial relationships between cells. The target protein of resveratrol was verified by performing a Western blot analysis.

After 24 h of treatment with resveratrol, HepG2 cell growth was inhibited in a dose-dependent manner. Resveratrol promotes cisplatin-induced HepG2 cell death through membrane-related pathways. It also significantly changes the membrane components of HepG2 cells. Additionally, resveratrol changes the morphology of the HepG2 cell membrane by decreasing the expression of PLA2G2.

Resveratrol changes the morphology of the HepG2 cell membrane by decreasing the expression of PLA2G2 and promotes cisplatin-induced HepG2 cell death. The combination of cisplatin and resveratrol can play a synergistic therapeutic effect on HepG2 cells.

Adult central nervous system (CNS) neurons down-regulate growth programs after injury, leading to persistent regeneration failure. Coordinated lipids metabolism is required to synthesize membrane components during axon regeneration. However, lipids also function as cell signaling molecules. Whether lipid signaling contributes to axon regeneration remains unclear. In this study, we showed that lipin1 orchestrates mechanistic target of rapamycin (mTOR) and STAT3 signaling pathways to determine axon regeneration. We established an mTOR-lipin1-phosphatidic acid/lysophosphatidic acid-mTOR loop that acts as a positive feedback inhibitory signaling, contributing to the persistent suppression of CNS axon regeneration following injury. In addition, lipin1 knockdown (KD) enhances corticospinal tract (CST) sprouting after unilateral pyramidotomy and promotes CST regeneration following complete spinal cord injury (SCI). Furthermore, lipin1 KD enhances sensory axon regeneration after SCI. Overall, our research reveals that lipin1 functions as a central regulator to coordinate mTOR and STAT3 signaling pathways in the CNS neurons and highlights the potential of lipin1 as a promising therapeutic target for promoting the regeneration of motor and sensory axons after SCI.