Long noncoding ribonucleic acid ENST00000517482 enhances mesenchymal stem cell therapy against acute lung injury

Abstract

Recent findings reveal that long non-coding RNA ENST00000517482 (ENST) protects mesenchymal stem cells (MSCs) from mitochondrial apoptosis via the microRNA-539/c-MYC axis, thereby enhancing their paracrine efficacy against lipopolysaccharide-induced acute lung injury (ALI) in vitro. Furthermore, ENST promotes autophagy through LC3B, autophagy related 7, and autophagy related 5, suggesting a dual role in MSC-mediated lung repair. However, translating these benefits to in vivo applications faces critical challenges. Autophagy, while protective in vitro, may exacerbate epithelial damage during ischemia-reperfusion or hyperoxic ALI if uncontrolled. Additionally, systemic MSC infusion suffers from poor pulmonary engraftment, limiting therapeutic efficiency. To overcome these barriers, future research should prioritize extracellular vehicle-based delivery of ENST-modified MSCs, combined with strategies to fine-tune autophagy via phosphatidylinositol 3-kinase/protein kinase B/mammalian target of the rapamycin or AMP-activated protein kinase/c-Jun-N-terminal kinase modulation. Rigorous validation in endotoxemia and ventilator-induced ALI models, with longitudinal assessment of autophagy and mitochondrial dynamics, will be essential to optimize this approach for clinical translation.

Key Words: Acute lung injury; AMP-activated protein kinase/c-Jun-N-terminal kinase; Autophagy; ENST00000517482; Extracellular vesicles; Mesenchymal stem cell; MicroRNA-539/c-MYC axis; Phosphatidylinositol 3-kinase/protein kinase B/mammalian target of the rapamycin; Stem-cell therapy

Core Tip: Long non-coding RNA ENST00000517482 enhances the survival of mesenchymal stem cells by protecting mitochondria from apoptosis through the microRNA-539 and c-MYC signaling axis. While this mechanism strengthens stem cell paracrine effects in vitro, its simultaneous activation of autophagy poses potential risks of aggravating lung tissue injury in living organisms. Furthermore, conventional systemic infusion of mesenchymal stem cells results in limited therapeutic efficiency due to poor lung targeting. This article emphasizes the importance of controlling autophagy levels and adopting extracellular vesicle-based delivery systems as critical steps to translate ENST00000517482-mediated stem cell therapies into safe and effective treatments for acute lung injury.

TO THE EDITOR

I read with great interest the recent article by Shen et al[1], which identified the long non-coding RNA (lncRNA) ENST00000517482 (ENST) as a key regulator of mitochondrial apoptosis in bone-marrow-derived mesenchymal stem cells (BMSCs). By sponging microRNA-539 (miR-539) and upregulating c-MYC, ENST significantly enhanced BMSC survival and paracrine cytoprotection in a lipopolysaccharide (LPS)-induced acute lung injury (ALI) model. In this study, BEAS-2B epithelial cells were exposed to 10 μg/mL LPS (Escherichia coli O111:B4) for 12 hours to mimic systemic inflammatory injury, providing a relevant in vitro platform for evaluating BMSC-mediated therapeutic effects.

Notably, ENST overexpression also increased autophagy-related markers [LC3B, autophagy related 7 (ATG7), ATG5], highlighting its dual role in modulating both apoptotic and autophagic pathways critical for lung tissue repair. This finding resonates with accumulating evidence that lncRNAs are pivotal modulators of mesenchymal stem cell (MSC) therapeutic efficacy. For example, exosomes derived from hypoxia-preconditioned MSCs enriched in lncRNA X-inactive specific transcript have been shown to attenuate LPS-induced ALI via the miR-455-3p/claudin-4 axis[2], while MSC-derived lncRNA-p21 ameliorates epithelial apoptosis through the miR-181/sirtuin 1 pathway in sepsis-induced ALI models[3]. Such studies support an emerging paradigm in which engineering MSCs or their extracellular vehicles (EVs) with functional lncRNAs can enhance regenerative outcomes[4]. Within this context, ENST represents a promising candidate for advancing cell-based therapies targeting ALI.

WHY IN-VIVO CONFIRMATION AND DELIVERY STRATEGY MATTER

Although ENST over-expression increased LC3B/ATG7/ATG5 and tempered apoptosis in culture, autophagy behaves as a double-edged sword once MSC reach an injured lung. Excessive autophagic flux can worsen epithelial damage in ischemia-reperfusion or hypertoxic ALI, and several groups report benefit from down-regulating autophagy in vivo through phosphatidylinositol 3-kinase/protein kinase B/mammalian target of the rapamycin or AMP-activated protein kinase/c-Jun-N-terminal kinase signaling[5-7]. I therefore encourage the authors to complement their discovery with a rigorous murine ALI model that measures autophagy and mitochondrial integrity longitudinally after cell infusion.

Equally important is how ENST is delivered. Systemic MSC administration leads to < 5% long-term engraftment, while their EVs freely traverse the alveolar-capillary barrier. Wharton’s-jelly MSC macrovesicles loaded with miR-100[8], adipose-MSC EVs carrying miR-320a[9], and exosomes pre-conditioned for proptosis inhibition have each mitigated histological and functional endpoints of ALI in rodents[10]. Engineered EVs are now being optimized to shuttle lncRNAs with high copy number and lung tropism, offering a practical route to test ENST in vivo[11].

POSITIONING ENST WITHIN THE BROADER LNCRNA LANDSCAPE

An expanding catalogue of pulmonary lncRNAs (including nuclear-enriched abundant transcript 1, HOX transcript antisense RNA, and X-inactive specific transcript) modulate inflammatory cell death, glycolytic re-programming, and mitogen-activated protein kinases signaling in ALI[8]. Mapping where ENST sits in this network could reveal cooperative or redundant pathways that fine-tune MSC cytoprotecting. Integrative RNA sequencing on ENST-overexpression vs knock-down MSCs exposed to hypoxia-reoxygenation, followed by single-cell tracking post-transplant, would help disentangle cell-intrinsic effects from paracrine immunomodulation.

FUTURE DIRECTIONS

To translate these priorities into a coherent pre-clinical roadmap, we propose first evaluating ENST-engineered MSCs or ENST-enriched EVs in at least two clinically relevant ALI phenotypes - endotoxemia and ventilator-induced - using survival and dynamic lung-compliance as the primary read-outs. Next, because autophagy can either aid or undermine transplanted cells, temporal pharmacologic blockade (e.g., bafilomycin-A1) or selective knock-in/knock-out of pivotal ATG genes should be deployed to delineate the therapeutic window in which autophagy sustains, rather than erodes, MSC persistence. Finally, pairing ENST delivery with nudix-hydrolase-1 inhibition or mild glycolytic pre-conditioning - both of which heighten the vulnerability of MYC-high cells to metabolic strain - could further bolster mitochondrial fitness and overall regenerative potency[1,12]. By nesting ENST within an EV-based, metabolically optimised platform and validating its performance in vivo, we stand a realistic chance of bypassing the apoptotic bottleneck that has long restricted MSC therapy for ALI.