Organ Repair Research Articles

Isolation, identification, and challenges of extracellular vesicles: emerging players in clinical applications.

Extracellular vesicles (EVs) serve as critical mediators of intercellular communication, encompassing exosomes, microvesicles, and apoptotic vesicles that play significant roles in diverse physiological and pathological contexts. Numerous studies have demonstrated that EVs derived from mesenchymal stem cells (MSC-EVs) play a pivotal role in facilitating tissue and organ repair, alleviating inflammation and apoptosis, enhancing the proliferation of endogenous stem cells within tissues and organs, and modulating immune function-these functions have been extensively utilized in clinical applications. The precise classification, isolation, and identification of MSC-EVs are essential for their clinical applications. This article provides a comprehensive overview of the biological properties of EVs, emphasizing both their advantages and limitations in isolation and identification methodologies. Additionally, we summarize the protein markers associated with MSC-EVs, emphasizing their significance in the treatment of various diseases. Finally, this article addresses the current challenges and dilemmas in developing clinical applications for MSC-EVs, aiming to offer valuable insights for future research.

Novel Porcine Model Reveals Two Distinct LGR5 Cell Types During Lung Development and Homeostasis.

Cells expressing LGR5 play a pivotal role in homeostasis, repair, and regeneration in multiple organs including skin and gastrointestinal tract, yet little is known about their role in the lung. Findings from mice, a widely used animal model, suggest that lung LGR5 expression differs from that of humans. In this work, using a new transgenic pig model, we identify two main populations of LGR5+ cells in the lung that are conserved in human, but not mouse lungs. Using RNA sequencing, 3D imaging and organoid models, we determine that in the fetal lung, epithelial LGR5 expression is transient in a subpopulation of SOX9+/ETV+/SFTPC+ progenitor lung tip cells. In contrast, epithelial LGR5 expression is absent from postnatal lung, but is reactivated in bronchioalveolar organoids derived from basal airway cells. We also describe a separate population of mesenchymal LGR5+ cells that surrounds developing and mature airways, lies adjacent to airway basal cells, and is closely associated with nerve fibers. Transcriptionally, mesenchymal LGR5+ cells include a subset of peribronchial fibroblasts (PBF) that express unique patterns of SHH, FGF, WNT and TGF-β signaling pathway genes. These results support distinct roles for LGR5+ cells in the lung and describe a physiologically relevant animal model for further studies on the function of these cells in repair and regeneration.

Printing Cell Embedded Sacrificial Strategy for Microvasculature using Degradable DNA Biolubricant

Microvasculature is essential for the continued function of cells in tissue and is fundamental in the fields of tissue engineering, organ repair and drug screening. However, the fabrication of microvasculature is still challenging using existing strategies. Here, we developed a general PRINting Cell Embedded Sacrificial Strategy (PRINCESS) and successfully fabricated microvasculatures using degradable DNA biolubricant. This is the first demonstration of direct cell printing to fabricate microvasculature, which eliminates the need for a subsequent cell seeding process and the associated deficiencies. Utilizing the shear‐thinning property of DNA hydrogels as a novel sacrificial, cell‐laden biolubricant, we can print a 70‐μm endothelialized microvasculature, breaking the limit of 100 μm. To our best knowledge, this is the smallest endothelialized microvasculature that has ever been bioprinted so far. In addition, the self‐healing property of DNA hydrogels allows the creation of continuous branched structures. This strategy provides a new platform for constructing complex hierarchical vascular networks and offers new opportunity towards engineering thick tissues. The extremely low volume of sacrificial biolubricant paves the way for DNA hydrogels to be used in practical tissue engineering applications. The high‐resolution bioprinting technique also exhibits great potential for printing lymphatics, retinas and neural networks in the future.

Printing Cell Embedded Sacrificial Strategy for Microvasculature using Degradable DNA Biolubricant.

Microvasculature is essential for the continued function of cells in tissue and is fundamental in the fields of tissue engineering, organ repair and drug screening. However, the fabrication of microvasculature is still challenging using existing strategies. Here, we developed a general PRINting Cell Embedded Sacrificial Strategy (PRINCESS) and successfully fabricated microvasculatures using degradable DNA biolubricant. This is the first demonstration of direct cell printing to fabricate microvasculature, which eliminates the need for a subsequent cell seeding process and the associated deficiencies. Utilizing the shear-thinning property of DNA hydrogels as a novel sacrificial, cell-laden biolubricant, we can print a 70-μm endothelialized microvasculature, breaking the limit of 100 μm. To our best knowledge, this is the smallest endothelialized microvasculature that has ever been bioprinted so far. In addition, the self-healing property of DNA hydrogels allows the creation of continuous branched structures. This strategy provides a new platform for constructing complex hierarchical vascular networks and offers new opportunity towards engineering thick tissues. The extremely low volume of sacrificial biolubricant paves the way for DNA hydrogels to be used in practical tissue engineering applications. The high-resolution bioprinting technique also exhibits great potential for printing lymphatics, retinas and neural networks in the future.

Application of Nanomaterials in the Repair and Regeneration of Lymphatic Organs and Corresponding Biophysical Simulation Strategies

Immune system diseases, malignant tumors, and traumatic injuries can directly damage the structure and function of lymphoid organs, while subsequent radiotherapy, chemotherapy, and lymph node dissection further damage the patient's immune system, leading to immune dysfunction, metabolic disorders, and increased susceptibility to infection, which seriously affect the patient's prognosis and quality of life. In this context, nanotechnology plays a key role in lymphoid organ regeneration and immune function recovery, including improving the therapeutic effect through targeted drug delivery systems, using targeted imaging probes to achieve tumor prediction and early detection, combining nanoplatforms with immunotherapy and photodynamic therapy to achieve synergistic therapeutic effects, and using nanomaterials to regulate the tumor microenvironment to enhance the sensitivity of traditional treatments. In addition, biophysical simulation strategies that simulate the microenvironment of lymphoid organs have also attracted widespread attention, aiming to construct a native cell environment to support the regeneration and functional recovery of damaged lymphoid tissues, or to simulate immune cells to regulate lymphocytes and induce specific immune responses. The multifaceted application of nanotechnology provides promising prospects for lymphoid organ regeneration and immune system repair.

7877 Adipose Depot Differences In Regenerative Properties Of Exosomes Derived From Human Adipose Stem Cells

Abstract Disclosure: M.A. Krause-Hauch: None. R. Patel: None. B. Osborne: None. P. Albear: None. N.A. Patel: None. Many patients struggle with chronic recalcitrant wounds that are the result of delayed healing. Underlying inflammation is one major risk factor for impaired dermal wound healing that may lead to pathologies such as infection and scarring. Adult human adipose stem cells (hASCs) have shown tremendous potential in regenerative medicine. The regenerative potential of hASCs is dependent on secreted bioactive material which is packaged and released in extracellular exosomes. We previously showed that hASC exosomes from the subcutaneous depot (sc) promoted repair in human dermal fibroblasts using in vitro assays. In this study, we evaluated exosomes derived from the omental depot (om) of hASC and compared its efficacy with sc-hASC. Our results show differences in levels of the long noncoding RNA (lncRNA) cargo between om-hASCexo and sc-hASCexo. Next, we evaluated their repair potential in a wound model in vivo. Male and female F344 rats were dorsally wounded via punch biopsy and silicone scaffolding was attached to prevent contraction. The wounds were then either not treated (control) or treated with 50μg om-hASCexo or sc-hASCexo every alternate day when each wound size was measured for 1 week to monitor healing progress. After 7 days, wounds treated with either om-hASCexo and sc-hASCexo closed significantly faster than untreated control wounds. While no difference was observed in closure percentage after 7 days for wounds treated with either om-hASCexo and sc-hASCexo, sc-hASCexo appeared to act faster earlier (1-2 days post wound) in the wound healing process while om-hASCexo acts faster during later stages (2-4 days post wound) of wound healing. The wound tissue was collected for biochemical and histological analysis. qPCR analysis on day 7 revealed that both om-hASCexo and sc-hASCexo treatment resulted in increased levels of Collagen 1 & 3 and MMP9, while levels of TGF-β decreased with treatment. These results indicate that om-hASCexo and sc-hASCexo enhanced the wound healing process while decreasing inflammation of the wound. To determine the differences between om-hASCexo and sc-hASCexo treatments on wound healing pathways, RNAseq was performed. Results show specificity in pathway activation and gene expression between the om-hASCexo and sc-hASCexo treatments. In conclusion, we have demonstrated that the regenerative mechanisms differ between the hASC depots from which exosomes are secreted. At a broader level, this finding may shed light on the body’s organ health and repair processes in normal or disease states. Presentation: 6/3/2024

Research Status and Safety Considerations of Animal-Derived Mesh Products

With the development of the economy and technological progress, more and more animal-derived mesh products are being utilized in the medical field for tissue and organ repair and replacement. Owing to the complexity of their structure and production process, these animal-derived meshes still face several challenges in practical applications, such as insufficient mechanical strength, rapid degradation rates, and the detection of harmful leachable substances. Among these challenges, the production process is a key factor affecting product quality. This paper reviews the key aspects of the production process and quality control for animal-derived meshes in China, offering new insights for the quality control and regulatory oversight of such products.

Study on Printability Evaluation of Alginate/Silk Fibroin/Collagen Double-Cross-Linked Inks and the Properties of 3D Printed Constructs.

In recent years, biological 3D printing has garnered increasing attention for tissue and organ repair. The challenge with 3D-printing inks is to combine mechanical properties as well as biocompatibility. Proteins serve as vital structural components in living systems, and utilizing protein-based inks can ensure that the materials maintain the necessary biological activity. In this study, we incorporated two natural biomaterials, silk fibroin (SF) and collagen (COL), into a low-concentration sodium alginate (SA) solution to create novel composite inks. SF and COL were modified with glycidyl methacrylate (GMA) to impart photo-cross-linking properties. The UV light test and 1H NMR results demonstrated successful curing of silk fibroin (SF) and collagen (COL) after modification and grafting. Subsequently, the printability of modified silk fibroin (RSFMA)/SA with varying concentration gradients was assessed using a set of three consecutive printing models, and the material's properties were tested. The research results prove that the addition of RSFMA and ColMA enhances the printability of low-concentration SA solutions, with the Pr values increasing from 0.85 ± 0.02 to 0.90 ± 0.03 and 0.92 ± 0.02, respectively, and the mechanical strength increasing from 0.19 ± 0.01 to 0.28 ± 0.01 and 0.38 ± 0.01 MPa; cytocompatibility has also been improved. Furthermore, rheological tests indicated that all of the inks exhibited shear thinning properties. CCK-8 experiments demonstrated that the addition of ColMA increased the cytocompatibility of the ink system. Overall, the utilization of SF and COL-modified SA materials as inks represents a promising advancement in 3D-printed ink technology.

Production of Nanofibrillar Patterned Collagen for Tissue Engineering.

Regenerative biomaterials are designed to facilitate cell-material interactions to guide the repair of damaged tissues and organs. These materials are designed to emulate the biophysical properties of native tissue, providing cellular phenotypic and morphological guidance that contributes to the restoration of the regenerative tissue niche. Collagen, a prevalent extracellular matrix protein, is a common component of these regenerative biomaterials due to its biocompatibility and other favorable properties. The current study describes a novel and straightforward method for the fabrication of engineered nanofibrillar collagen with directed fibril patterning. Through the manipulation of shear stress, temperature, and pH, collagen fibrillogenesis and alignment are precisely controlled without requiring specialized equipment. This approach allows for the creation of nanofibrillar collagen biomaterials that mimic the native structure of tissues exhibiting either anisotropic or isotropic characteristics. The flexibility in collagen nanofibril patterning not only facilitates the study of nanoscale patterning on cell behavior but also offers diverse possibilities for patterned tissue engineering applications.

Role of Agrin in tissue repair and regeneration: From mechanisms to therapeutic opportunities (Review).

Tissue regeneration is a complex process that involves the recruitment of various types of cells for healing after injury; it is mediated by numerous precise interactions. However, the identification of effective targets for improving tissue regeneration remains a challenge. As an extracellular matrix protein, Agrin plays a critical role in neuromuscular junction formation. Furthermore, recent studies have revealed the role of Agrin in regulating tissue proliferation and regeneration, which contributes to the repair process of injured tissues. An in‑depth understanding of the role of Agrin will therefore be of value. Given that repair and regeneration processes occur in various parts of the human body, the present systematic review focuses on the role of Agrin in typical tissue and highlights the potential signaling pathways that are involved in Agrin‑induced repair and regeneration. This review offers important insight into novel strategies for the future clinical applications of Agrin‑based therapies, which may represent a feasible treatment option for patients who require organ replacement or repair.

Low-Volume Ex Situ Lung Perfusion System for Single Lung Application in a Small Animal Model Enables Optimal Compliance With "Reduction" in 3R Principles of Animal Research.

Ex situ lung perfusion (ESLP) is used for organ reconditioning, repair, and re-evaluation prior to transplantation. Since valid preclinical animal models are required for translationally relevant studies, we developed a 17mL low-volume ESLP for double- and single-lung application that enables cost-effective optimal compliance "reduction" of the 3R principles of animal research. In single-lung mode, ten Fischer344 and Lewis rat lungs were subjected to ESLP and static cold storage using STEEN or PerfadexPlus. Key perfusion parameters, thermal lung imaging, blood gas analysis (BGA), colloid oncotic pressure (COP), lung weight gain, histological work-up, and cytokine analysis were performed. Significant differences between perfusion solutions but not between the rat strains were detected. Most relevant perfusion parameters confirmed valid ESLP with homogeneous lung perfusion, evidenced by uniform lung surface temperature. BGA showed temperature-dependent metabolic activities with differences depending on perfusion solution composition. COP is not decisive for pulmonary oedema and associated weight gain, but possibly rather observed chemokine profile and dextran sensitivity of rats. Histological examination confirmed intact lung architecture without infarcts or hemorrhages due to optimal organ procurement and single-lung application protocol using our in-house-designed ESLP system.

Spatial transcriptomics defines injury specific microenvironments and cellular interactions in kidney regeneration and disease

Kidney injury disrupts the intricate renal architecture and triggers limited regeneration, together with injury-invoked inflammation and fibrosis. Deciphering the molecular pathways and cellular interactions driving these processes is challenging due to the complex tissue structure. Here, we apply single cell spatial transcriptomics to examine ischemia-reperfusion injury in the mouse kidney. Spatial transcriptomics reveals injury-specific and spatially-dependent gene expression patterns in distinct cellular microenvironments within the kidney and predicts Clcf1-Crfl1 in a molecular interplay between persistently injured proximal tubule cells and their neighboring fibroblasts. Immune cell types play a critical role in organ repair. Spatial analysis identifies cellular microenvironments resembling early tertiary lymphoid structures and associated molecular pathways. Collectively, this study supports a focus on molecular interactions in cellular microenvironments to enhance understanding of injury, repair and disease.

Metabolomic studies reveal an organ-protective hibernation state in donor lungs preserved at 10 °C

ObjectivePrevious reports showed enhanced graft function in both healthy and injured porcine lungs after preservation at 10 °C. The objective of the study is to elucidate the mechanism of lung protection by 10 °C and identify potential therapeutic targets to improve organ preservation. MethodsMetabolomics data were analyzed from healthy and injured porcine lungs that underwent extended hypothermic preservation on ice and at 10 °C. Tissue sampled before and after preservation were subjected to untargeted metabolic profiling. Principal component analysis was performed to test for the separability of the paired samples. Significantly changed metabolites between the 2 time points were identified and analyzed to determine the underlying metabolic pathways. The levels of respiratory activity of lung tissue at hypothermic temperatures were confirmed using high resolution respirometry. ResultsIn both healthy and injured lungs (n = 5 per intervention), principal component analysis suggested minimal change in metabolites after ice preservation but significant change of metabolites after 10 °C preservation, which was associated with significantly improved lung function as assessed by ex vivo lung perfusion and lung transplantation. For healthy lungs, lipid energy pathway was found primarily active at 10 °C. For injured lungs, additional carbohydrate energy pathway and anti-ferroptosis pathways aiding organ repair were identified. These metabolic features are also key features involved in mammal hibernation. ConclusionsUntargeted metabolomics revealed a dynamic metabolic gradient for lungs stored at 10 °C. Elucidating the underlying mechanisms behind this pathway regulation may lead to strategies that will allow organs "hibernate" for days, potentially making organ banking a reality.

Developments and Opportunities for 3D Bioprinted Organoids.

Organoids developed from pluripotent stem cells or adult stem cells are three-dimensional cell cultures possessing certain key characteristics of their organ counterparts, and they can mimic certain biological developmental processes of organs in vitro. Therefore, they have promising applications in drug screening, disease modeling, and regenerative repair of tissues and organs. However, the construction of organoids currently faces numerous challenges, such as breakthroughs in scale size, vascularization, better reproducibility, and precise architecture in time and space. Recently, the application of bioprinting has accelerated the process of organoid construction. In this review, we present current bioprinting techniques and the application of bioinks and summarize examples of successful organoid bioprinting. In the future, a multidisciplinary combination of developmental biology, disease pathology, cell biology, and materials science will aid in overcoming the obstacles pertaining to the bioprinting of organoids. The combination of bioprinting and organoids with a focus on structure and function can facilitate further development of real organs.

Aerobic mechanochemical reversible-deactivation radical polymerization

Polymer materials suffer mechano-oxidative deterioration or degradation in the presence of molecular oxygen and mechanical forces. In contrast, aerobic biological activities combined with mechanical stimulus promote tissue regeneration and repair in various organs. A synthetic approach in which molecular oxygen and mechanical energy synergistically initiate polymerization will afford similar robustness in polymeric materials. Herein, aerobic mechanochemical reversible-deactivation radical polymerization was developed by the design of an organic mechano-labile initiator which converts oxygen into activators in response to ball milling, enabling the reaction to proceed in the air with low-energy input, operative simplicity, and the avoidance of potentially harmful organic solvents. In addition, this approach not only complements the existing methods to access well-defined polymers but also has been successfully employed for the controlled polymerization of (meth)acrylates, styrenic monomers and solid acrylamides as well as the synthesis of polymer/perovskite hybrids without solvent at room temperature which are inaccessible by other means.

The I-Guana Shot Protocol, An Intracavernosal Application of Wharton's Jelly Stem Cells for the Treatment of Erectile Dysfunction, Phase II Study

Umbilical cord has become an increasingly used source of mesenchymal stromal cells for preclinical and, more recently, clinical studies. Different clinical uses on multiple anatomical structures have demonstrated the safe use of the umbilical cord tissue and derivates with multiple potentially different options to treat difficult diseases or clinical conditions. Immunophenotypic analysis and characterization of stem cells isolated from Wharton’s jelly via various methods is currently underway in clinical research. Stem cells are the body’s basic cells from which all other cells with specialized functions are generated. Under the right conditions in the body or perinatal environment, stem cells divide to form more new cells. These new cells become stem cells (self-renewal type of cells), and can also become specialized cells (differentiated) with more specific functions, such as blood cells, brain cells, heart muscle, urinary and genital tract, bone, etc. No other cell in the body has the natural ability to generate new cell types as stem cells do. As with any emerging scientific/medical field having such incredible potential, numerous research trials and data gathering efforts are currently being conducted world-wide. New data is being reported daily that present compelling cases for therapies using certain pathologies on selected patients. Scientists have been working for decades to harness the regenerative “power” of stem cells for the possible repair and rejuvenation of certain organs to activate tissue regeneration. The ultimate objectives of all these studies are the same: deliver transformative therapies. The capacity for these cells to transform into whatever cells or tissues that the body may need to regenerate itself could, within the next 3 generations, potentially provide the means to successfully treat blindness, spinal cord injuries, diabetes, cystic fibrosis, muscular dystrophy, or even erectile dysfunction in affected patients. Such future outcomes may be possible for candidate patients who are fortunate enough to have access to those scientific and evidence- based medical protocols that use such potent biological sources. It is vital that, in the light of the dazzling potential, mesenchymal stem cells research and medical applications continue, especially for compassionate medical use (e.g. for No Option patients).

Instantly adhesive and ultra-elastic patches for dynamic organ and wound repair

Bioadhesive materials and patches are promising alternatives to surgical sutures and staples. However, many existing bioadhesives do not meet the functional requirements of current surgical procedures and interventions. Here, we present a translational patch material that exhibits instant adhesion to tissues (2.5-fold stronger than Tisseel, an FDA-approved fibrin glue), ultra-stretchability (stretching to >300% its original length without losing elasticity), compatibility with rapid photo-projection (<2 min fabrication time/patch), and ability to deliver therapeutics. Using our established procedures for the in silico design and optimization of anisotropic-auxetic patches, we created next-generation patches for instant attachment to tissues while conforming to a broad range of organ mechanics ex vivo and in vivo. Patches coated with extracellular vesicles derived from mesenchymal stem cells demonstrate robust wound healing capability in vivo without inducing a foreign body response and without the need for patch removal that can cause pain and bleeding. We further demonstrate a single material-based, void-filling auxetic patch designed for the treatment of lung puncture wounds.

Double-negative T cells have a reparative role after experimental severe ischemic acute kidney injury.

T cells mediate organ injury and repair. A proportion of unconventional kidney T cells called double-negative (DN) T cells (TCR+ CD4- CD8-), with anti-inflammatory properties, were previously demonstrated to protect from early injury in moderate experimental acute kidney injury (AKI). However, their role in repair after AKI has not been studied. We hypothesized that DN T cells mediate repair after severe AKI. C57B6 mice underwent severe (40 min) unilateral ischemia-reperfusion injury (IRI). Kidney DN T cells were studied by flow cytometry and compared with gold-standard anti-inflammatory CD4+ regulatory T cells (Tregs). In vitro effects of DN T cells and Tregs on renal tubular epithelial cell (RTEC) repair after injury were quantified with live-cell analysis. DN T cells, Tregs, CD4, or vehicle were adoptively transferred after severe AKI. Glomerular filtration rate (GFR) was measured using fluorescein isothiocyanate (FITC)-sinistrin. Fibrosis was assessed with Masson's trichrome staining. Profibrotic genes were measured with qRT-PCR. Percentages and the numbers of DN T cells substantially decreased during repair phase after severe AKI, as well as their activation and proliferation. Both DN T cells and Tregs accelerated RTEC cell repair in vitro. Post-AKI transfer of DN T cells reduced kidney fibrosis and improved GFR, as did Treg transfer. DN T cell transfer lowered transforming growth factor (TGF)β1 and α-smooth muscle actin (αSMA) expression. DN T cells reduced effector-memory CD4+ T cells and IL-17 expression. DN T cells undergo quantitative and phenotypical changes after severe AKI, accelerate RTEC repair in vitro as well as improve GFR and renal fibrosis in vivo. DN T cells have potential as immunotherapy to accelerate repair after AKI.NEW & NOTEWORTHY Double-negative (DN) T cells (CD4- CD8-) are unconventional kidney T cells with regulatory abilities. Their role in repair from acute kidney injury (AKI) is unknown. Kidney DN T cell population decreased during repair after ischemic AKI, in contrast to regulatory T cells (Tregs) which increased. DN T cell administration accelerated tubular repair in vitro, while after severe in vivo ischemic injury reduced kidney fibrosis and increased glomerular filtration rate (GFR). DN T cell infusion is a potential therapeutic agent to improve outcome from severe AKI.

Shape-fixing hydrogel promotes scarless healing of wounds under tension

The healing of a wound under tension (hereafter, “tension wound”) often coincides with the development of hypertrophic scars in clinical settings. Currently, compress bandages offer a potential alternative for the healing of tension wounds; however, their application in surgery is limited due to their prefabricated patch form. To overcome this, a tension-shielding hydrogel system was designed using photocurable catechol-grafted hyaluronic acid and tannic-acid silver nanoparticles (hereafter, “HTA system”). The hydrogel exhibited tension-shielding capacity, reducing wound tension via shape-fixation and ultimately reducing scar formation. The HTA hydrogel exhibited superior photothermal antibacterial efficacy, self-healing properties, and effective dissipation of energy, thereby promoting tissue regeneration. The hydrogel significantly inhibited the mechanotransduction pathway, thus preventing Engrailed-1 activation and reducing the fibrotic response. The HTA hydrogel system, therefore, provides a treatment strategy for tension wounds, burn wounds and other wounds that are prone to form hypertrophic scars via creating a tension-free local environment. Statement of significanceIn our study, we presented a wound-dressing hydrogel system (HTA) that exhibit shape-fixing capacity in tension wound model. Here, we designed and modified a tension regulator, applied it to mice, and furthermore, established a tension wound model in mice with adjustable tension. Outcomes showed that the HTA hydrogel system can effectively form a shape-fixed environment on tension wounds and dynamic wounds, thus promoting scarless healing. Additionally, HTA performs injectability, rapid crosslinking, biocompatibility, wet adhesion, hemostasis and photothermal antibacterial properties. We believe this research has various potential clinical applications, including scarless-healing in tension wounds, treatment of acute bleeding, treatment of infected wounds, and even internal organ repair.

Exosomes enriched by miR-429-3p derived from ITGB1 modified Telocytes alleviates hypoxia-induced pulmonary arterial hypertension through regulating Rac1 expression

BackgroundRecent studies have emphasized the critical role of Telocytes (TCs)-derived exosomes in organ tissue injury and repair. Our previous research showed a significant increase in ITGB1 within TCs. Pulmonary Arterial Hypertension (PAH) is marked by a loss of microvessel regeneration and progressive vascular remodeling. This study aims to investigate whether exosomes derived from ITGB1-modified TCs (ITGB1-Exo) could mitigate PAH.MethodsWe analyzed differentially expressed microRNAs (DEmiRs) in TCs using Affymetrix Genechip miRNA 4.0 arrays. Exosomes isolated from TC culture supernatants were verified through transmission electron microscopy and Nanoparticle Tracking Analysis. The impact of miR-429-3p-enriched exosomes (Exo-ITGB1) on hypoxia-induced pulmonary arterial smooth muscle cells (PASMCs) was evaluated using CCK-8, transwell assay, and inflammatory factor analysis. A four-week hypoxia-induced mouse model of PAH was constructed, and H&E staining, along with Immunofluorescence staining, were employed to assess PAH progression.ResultsForty-five miRNAs exhibited significant differential expression in TCs following ITGB1 knockdown. Mus-miR-429-3p, significantly upregulated in ITGB1-overexpressing TCs and in ITGB1-modified TC-derived exosomes, was selected for further investigation. Exo-ITGB1 notably inhibited the migration, proliferation, and inflammation of PASMCs by targeting Rac1. Overexpressing Rac1 partly counteracted Exo-ITGB1’s effects. In vivo administration of Exo-ITGB1 effectively reduced pulmonary vascular remodeling and inflammation.ConclusionsOur findings reveal that ITGB1-modified TC-derived exosomes exert anti-inflammatory effects and reverse vascular remodeling through the miR-429-3p/Rac1 axis. This provides potential therapeutic strategies for PAH treatment.Graphical 1. Identification of Differentially Expressed microRNAs (DEmiRs) in ITGB1 overexpressed TCs.2. Effects of Exo-ITGB1 or miR-429-3p on Hypoxia-Induced PASMCs in vitro.3. Exo-ITGB1 inhibits the hyper-proliferation and migration of PASMCs through regulating miR-429-3p/Rac1 axis in vitro.4. The therapeutic potential of Exo-ITGB1 in hypoxia-induced PAH model in vivo.