Protein hairy enhancer of split-1 expression during differentiation of muscle-derived stem cells into neuron-like cells

Muscle-derived stem cells were isolated from the skeletal muscle of Sprague-Dawley neonatal rats aged 3 days old. Cells at passage 5 were incubated in Dulbecco＇s modified Eagle＇s medium supplemented with 10% （v/v） fetal bovine serum, 20 IJg/L nerve growth factor, 20 pg/L basic fibroblast growth factor and 1% （v/v） penicillin for 6 days. Cells presented with long processes, similar to nerve cells. Connections were formed between cell processes. Immunocytochemical staining with neuron specific enolase verified that cells differentiated into neuron-like cells. Immunofluorescence cytochemistry and western blot results revealed that the expression of protein hairy enhancer of split-1 was significantly reduced. These results indicate that low expression of protein hairy enhancer of split-1 participates in the differentiation of muscle-derived stem cells into neuron-like cells.

Therapeutic capacities of human and mouse skeletal muscle-derived stem cells for a long gap peripheral nerve injury

An overview of a long-gap peripheral nerve therapy： A long- gap peripheral nerve transection injury is an irreparable injury to the living body, and mostly leads to permanent loss of re- lated motor and sensory functions. In such long gap injuries, nerve end-to-end suture is physically impossible. Therefore, bridging a long nerve-gap is critical to re-establish adequate mechanical support for separated nerve ends, and prevent the diffusion of neurotrophic and neurotropic factors secreted by transected stumps （Deumens et al., 2010）.

Negative effects of Notch1 on the differentiation of muscle-derived stem cells into neuronal-like cells

We cultured rat muscle-derived stem cells in medium containing nerve growth factor and basic fi-broblast growth factor to induce neuronal-like cell differentiation.Immunocytochemical staining and reverse transcription-PCR showed that the differentiated muscle-derived stem cells exhibited processes similar to those of neuronal-like cells and neuron-specific enolase expression,but Notch1 mRNA and protein expression was decreased.Down-regulation of Notch1 expression may facilitate neuronal-like cell differentiation from muscle-derived stem cells.

Can muscle-derived stem cells serve as seed cells to repair spinal cord injury?

Muscle-derived stem cells （MDSCs） can come from a number of different sources, which are easy to isolate and culture, and are also useful in the transformation and expression of exogenous genes. Therefore, MDSCs could possibly be used for gene therapy in the treatment of neurological diseases. However, research on MDSCs has focused on identifying phenotypes and induced differentiation, with few in vivo animal experiments conducted. In this study, MDSCs were selected as seed cells and implanted into the rat spinal cord injury area. Results demonstrated that the MDSCs survived, migrated, and were distributed along the spinal nerves. Moreover, the motor function of rat lower limbs improved significantly, suggesting that MDSCs could be used as seed cells to repair spinal cord injury.

Skeletal Muscle-derived Stem Cells Exhibit Cardiocyte Competences

Adult stem cells from skeletal muscle cells were induced to differentiate into cardiocytes to see if stem cells from another different but histologically-comparable tissues can differentiate to the target cells. Skeletal muscles-derived stem cells （MDSCs） were isolated from adult skeleton muscle tissues by differential adhesion, and immunocytochemically identified by using Sca-1. In order to induce the proliferation but not differentiation of MDSCs, the cells were cultured in Dulbecco’s modified Eagle’s medium/F12 （DMEM/F12） supplemented with 1：50 B27, 20 ng/mL basic fibroblast growth factor （bFGF）, 20 ng/mL epidermal growth factor （EGF） in a suspension for 6 days. Then these stem cells were treated with 5 μmol/L 5-azacytidine for 24 h in an adherence culture. The characteristics of induced cells were examined by immunocytochemistry, quantitative real time RT-PCR and morphological observation of cell phenotype. Our results showed that the appearance of some cells gradually changed from spindle-shape into polygonal or short-column-shape. Some of these post-treated cells could contract spontaneously and rhythmically. The expression of GATA-4 and cTnT was increased 1 and 2 week（s） after the treatment. And about 16.6% of post-treated cells were cTnT-positive. Therefore, we are led to conclude that skeletal muscle-derived stem cells could differentiate into cardiocyte-like cells, which exhibited some characteristics of cardiocytes.

TGF-β1-induced Synthesis of Collagen Fibers in Skeletal Muscle-Derived Stem Cells

The aim of this study was to investigate the mechanism of deposition of extracellular matrix induced by TGF-β1 in skeletal muscle-derived stem cells （MDSCs）. Rat skeletal MDSCs were obtained by using preplate technique, and divided into four groups： group A （control group）, group B （treated with TGF-β1, 10 ng/rnL）, group C （treated with TGF-β1 and anti-connective tissue growth factor （CTGF）, both in 10 ng/mL）, and group D （treated with anti-CTGF, 10 ng/mL）. The expression of CTGF, collagen type- I （COL- I ） and collagen type-III （COL-III） in MDSCs was examined by using RT-PCR, Western blot and immunofluorescent stain. It was found that one day after TGF-β1 treatment, the expression of CTGF, COL- I and COL-Ⅲ was increased dramatically. CTGF expression reached the peak on the day 2, and then decreased rapidly to a level of control group on the day 5. COL- I and COL-Ⅲ mRNA levels were overexpresed on the day 2 and 3 respectively, while their protein expression levels were up-regulated on the day 2 and reached the peak on the day 7. In group C, anti-CTGF could partly suppress the overexpression of COL-I and COL-Ill induced by TGF-131 one day after adding CTGF antibody. It was concluded that TGF-β1 could induce MDSCs to express CTGF, and promote the production of COL- I and COL-III. In contrast, CTGF antibody could partially inhibit the effect of TGF-β1 on the MDSCs by reducing the expression of COL- I and COL-III. Taken together, we demonstrated that TGF-β1-CTGF signaling played a crucial role in MDSCs synthesizing collagen proteins in vitro, which provided theoretical basis for exploring the methods postponing skeletal muscle fibrosis after nerve injury.

Research progress in muscle-derived stem cells Literature retrieval results based on international database

OBJECTIVE： To identify global research trends of muscle-derived stem cells （MDSCs） using a bibliometric analysis of the Web of Science, Research Portfolio Online Reporting Tools of the National Institutes of Health （NIH）, and the Clinical Trials registry database （ClinicalTrials.gov）. DATA RETRIEVAL： We performed a bibliometric analysis of data retrievals for MDSCs from 2002 to 2011 using the Web of Science, NIH, and ClinicalTrials.gov. SELECTION CRITERIA： Inclusion criteria： （1） Web of Science： （a） peer-reviewed articles on MDSCs that were published and indexed in the Web of Science. （b） Type of articles： original research articles, reviews, meeting abstracts, proceedings papers, book chapters, editorial material and news items. （c） Year of publication： 2002-2011. （d） Citation databases： Science Citation Index-Expanded （SCI-E）, 1899-present; Conference Proceedings Citation Index-Science （CPCI-S）, 1991-present; Book Citation Index-Science （BKCI-S）, 2005-present. （2） NIH： （a） Projects on MDSCs supported by the NIH. （b） Fiscal year： 1988-present. （3） ClinicalTrials.gov： All clinical trials relating to MDSCs were searched in this database. Exclusion criteria： （1） Web of Science： （a） Articles that required manual searching or telephone access. （b） We excluded documents that were not published in the public domain. （c） We excluded a number of corrected papers from the total number of articles. （d） We excluded articles from the following databases： Social Sciences Citation Index （SSCI）, 1898-present; Arts ＆ Humanities Citation Index （A＆HCI）, 1975-present; Conference Proceedings Citation Index - Social Science ＆ Humanities （CPCI-SSH）, 1991-present; Book Citation Index - Social Sciences ＆ Humanities （BKCI-SSH）, 2005-present; Current Chemical Reactions （CCR-EXPANDED）, 1985-present; Index Chemicus （IC）, 1993-present. （2） NIH： （a） We excluded publications related to MDSCs that were supported by the NIH. （b） We limited the keyword search to studies that included MDSCs within the title or abstract. （3） ClinicalTrials.gov： （a） We excluded clinical trials that were not in the ClinicalTrials.gov database. （b） We excluded clinical trials that dealt with stem cells other than MDSCs in the ClinicalTrials.gov database. MAIN OUTCOME MEASURES： （1） Type of literature; （2） annual publication output; （3） distribution according to journals; （4） distribution according to country; （5） distribution according to institution; （6） top cited authors over the last 10 years; （7） projects financially supported by the NIH; and （8） clinical trials registered. RESULTS： （1） In all, 802 studies on MDSCs appeared in the Web of Science from 2002 to 2011, almost half of which derived from American authors and institutes. The number of studies on MDSCs has gradually increased over the past 10 years. Most papers on MDSCs appeared in journals with a particular focus on cell biology research, such as Experimental Cell Research, Journal of Cell Science, and PLoS One. （2） Eight MDSC research projects have received over US$6 billion in funding from the NIH. The current project led by Dr. Johnny Huard of the University of Pittsburgh-＂Muscle-Based Tissue Engineering to Improve Bone Healing＂-is supported by the NIH. Dr. Huard has been the most productive and top-cited author in the field of gene therapy and adult stem cell research in the Web of Science over last 10 years. （3） On ClinicalTrials.gov, ＂Muscle Derived Cell Therapy for Bladder Exstrophy Epispadias Induced Incontinence＂ Phase 1 is registered and sponsored by Johns Hopkins University and has been led by Dr. John P. Gearhart since November 2009. CONCLUSION： From our analysis of the literature and research trends, we found that MDSCs may offer further benefits in regenerative medicine.

Mechanism of inflammatory response and therapeutic effects of stem cells in ischemic stroke:current evidence and future perspectives

Ischemic stroke is a leading cause of death and disability worldwide,with an increasing trend and tendency for onset at a younger age.China,in particular,bears a high burden of stroke cases.In recent years,the inflammatory response after stroke has become a research hotspot:understanding the role of inflammatory response in tissue damage and repair following ischemic stroke is an important direction for its treatment.This review summarizes several major cells involved in the inflammatory response following ischemic stroke,including microglia,neutrophils,monocytes,lymphocytes,and astrocytes.Additionally,we have also highlighted the recent progress in various treatments for ischemic stroke,particularly in the field of stem cell therapy.Overall,understanding the complex interactions between inflammation and ischemic stroke can provide valuable insights for developing treatment strategies and improving patient outcomes.Stem cell therapy may potentially become an important component of ischemic stroke treatment.

Photobiomodulation:a novel approach to promote trans-differentiation of adipose-derived stem cells into neuronal-like cells

Photobiomodulation,originally used red and near-infrared lasers,can alter cellular metabolism.It has been demonstrated that the visible spectrum at 451-540 nm does not necessarily increase cell proliferation,near-infrared light promotes adipose stem cell proliferation and affects adipose stem cell migration,which is necessary for the cells homing to the site of injury.In this in vitro study,we explored the potential of adipose-derived stem cells to differentiate into neurons for future translational regenerative treatments in neurodegenerative disorders and brain injuries.We investigated the effects of various biological and chemical inducers on trans-differentiation and evaluated the impact of photobiomodulation using 825 nm near-infrared and 525 nm green laser light at 5 J/cm2.As adipose-derived stem cells can be used in autologous grafting and photobiomodulation has been shown to have biostimulatory effects.Our findings reveal that adipose-derived stem cells can indeed trans-differentiate into neuronal cells when exposed to inducers,with pre-induced cells exhibiting higher rates of proliferation and trans-differentiation compared with the control group.Interestingly,green laser light stimulation led to notable morphological changes indicative of enhanced trans-differentiation,while near-infrared photobiomodulation notably increased the expression of neuronal markers.Through biochemical analysis and enzyme-linked immunosorbent assays,we observed marked improvements in viability,proliferation,membrane permeability,and mitochondrial membrane potential,as well as increased protein levels of neuron-specific enolase and ciliary neurotrophic factor.Overall,our results demonstrate the efficacy of photobiomodulation in enhancing the trans-differentiation ability of adipose-derived stem cells,offering promising prospects for their use in regenerative medicine for neurodegenerative disorders and brain injuries.

Therapeutic potential of stem cells in subarachnoid hemorrhage

Aneurysm rupture can result in subarachnoid hemorrhage,a condition with potentially severe consequences,such as disability and death.In the acute stage,early brain injury manifests as intracranial pressure elevation,global cerebral ischemia,acute hydrocephalus,and direct blood–brain contact due to aneurysm rupture.This may subsequently cause delayed cerebral infarction,often with cerebral vasospasm,significantly affecting patient outcomes.Chronic complications such as brain volume loss and chronic hydrocephalus can further impact outcomes.Investigating the mechanisms of subarachnoid hemorrhage-induced brain injury is paramount for identifying effective treatments.Stem cell therapy,with its multipotent differentiation capacity and anti-inflammatory effects,has emerged as a promising approach for treating previously deemed incurable conditions.This review focuses on the potential application of stem cells in subarachnoid hemorrhage pathology and explores their role in neurogenesis and as a therapeutic intervention in preclinical and clinical subarachnoid hemorrhage studies.

Advances in therapies using mesenchymal stem cells and their exosomes for treatment of peripheral nerve injury:state of the art and future perspectives

“Peripheral nerve injury”refers to damage or trauma affecting nerves outside the brain and spinal cord.Peripheral nerve injury results in movements or sensation impairments,and represents a serious public health problem.Although severed peripheral nerves have been effectively joined and various therapies have been offered,recovery of sensory or motor functions remains limited,and efficacious therapies for complete repair of a nerve injury remain elusive.The emerging field of mesenchymal stem cells and their exosome-based therapies hold promise for enhancing nerve regeneration and function.Mesenchymal stem cells,as large living cells responsive to the environment,secrete various factors and exosomes.The latter are nano-sized extracellular vesicles containing bioactive molecules such as proteins,microRNA,and messenger RNA derived from parent mesenchymal stem cells.Exosomes have pivotal roles in cell-to-cell communication and nervous tissue function,offering solutions to changes associated with cell-based therapies.Despite ongoing investigations,mesenchymal stem cells and mesenchymal stem cell-derived exosome-based therapies are in the exploratory stage.A comprehensive review of the latest preclinical experiments and clinical trials is essential for deep understanding of therapeutic strategies and for facilitating clinical translation.This review initially explores current investigations of mesenchymal stem cells and mesenchymal stem cell-derived exosomes in peripheral nerve injury,exploring the underlying mechanisms.Subsequently,it provides an overview of the current status of mesenchymal stem cell and exosomebased therapies in clinical trials,followed by a comparative analysis of therapies utilizing mesenchymal stem cells and exosomes.Finally,the review addresses the limitations and challenges associated with use of mesenchymal stem cell-derived exosomes,offering potential solutions and guiding future directions.

Induced neural stem cells regulate microglial activation through Akt-mediated upregulation of CXCR4 and Crry in a mouse model of closed head injury

Microglial activation that occurs rapidly after closed head injury may play important and complex roles in neuroinflammation-associated neuronal damage and repair.We previously reported that induced neural stem cells can modulate the behavior of activated microglia via CXCL12/CXCR4 signaling,influencing their activation such that they can promote neurological recovery.However,the mechanism of CXCR4 upregulation in induced neural stem cells remains unclear.In this study,we found that nuclear factor-κB activation induced by closed head injury mouse serum in microglia promoted CXCL12 and tumor necrosis factor-αexpression but suppressed insulin-like growth factor-1 expression.However,recombinant complement receptor 2-conjugated Crry(CR2-Crry)reduced the effects of closed head injury mouse serum-induced nuclear factor-κB activation in microglia and the levels of activated microglia,CXCL12,and tumor necrosis factor-α.Additionally,we observed that,in response to stimulation(including stimulation by CXCL12 secreted by activated microglia),CXCR4 and Crry levels can be upregulated in induced neural stem cells via the interplay among CXCL12/CXCR4,Crry,and Akt signaling to modulate microglial activation.In agreement with these in vitro experimental results,we found that Akt activation enhanced the immunoregulatory effects of induced neural stem cell grafts on microglial activation,leading to the promotion of neurological recovery via insulin-like growth factor-1 secretion and the neuroprotective effects of induced neural stem cell grafts through CXCR4 and Crry upregulation in the injured cortices of closed head injury mice.Notably,these beneficial effects of Akt activation in induced neural stem cells were positively correlated with the therapeutic effects of induced neural stem cells on neuronal injury,cerebral edema,and neurological disorders post–closed head injury.In conclusion,our findings reveal that Akt activation may enhance the immunoregulatory effects of induced neural stem cells on microglial activation via upregulation of CXCR4 and Crry,thereby promoting induced neural stem cell–mediated improvement of neuronal injury,cerebral edema,and neurological disorders following closed head injury.

Exosomes originating from neural stem cells undergoing necroptosis participate in cellular communication by inducing TSC2 upregulation of recipient cells following spinal cord injury

We previously demonstrated that inhibiting neural stem cells necroptosis enhances functional recovery after spinal cord injury.While exosomes are recognized as playing a pivotal role in neural stem cells exocrine function,their precise function in spinal cord injury remains unclear.To investigate the role of exosomes generated following neural stem cells necroptosis after spinal cord injury,we conducted singlecell RNA sequencing and validated that neural stem cells originate from ependymal cells and undergo necroptosis in response to spinal cord injury.Subsequently,we established an in vitro necroptosis model using neural stem cells isolated from embryonic mice aged 16-17 days and extracted exosomes.The results showed that necroptosis did not significantly impact the fundamental characteristics or number of exosomes.Transcriptome sequencing of exosomes in necroptosis group identified 108 differentially expressed messenger RNAs,104 long non-coding RNAs,720 circular RNAs,and 14 microRNAs compared with the control group.Construction of a competing endogenous RNA network identified the following hub genes:tuberous sclerosis 2(Tsc2),solute carrier family 16 member 3(Slc16a3),and forkhead box protein P1(Foxp1).Notably,a significant elevation in TSC2 expression was observed in spinal cord tissues following spinal cord injury.TSC2-positive cells were localized around SRY-box transcription factor 2-positive cells within the injury zone.Furthermore,in vitro analysis revealed increased TSC2 expression in exosomal receptor cells compared with other cells.Further assessment of cellular communication following spinal cord injury showed that Tsc2 was involved in ependymal cellular communication at 1 and 3 days post-injury through the epidermal growth factor and midkine signaling pathways.In addition,Slc16a3 participated in cellular communication in ependymal cells at 7 days post-injury via the vascular endothelial growth factor and macrophage migration inhibitory factor signaling pathways.Collectively,these findings confirm that exosomes derived from neural stem cells undergoing necroptosis play an important role in cellular communication after spinal cord injury and induce TSC2 upregulation in recipient cells.

Hypoxia-preconditioned bone marrow-derived mesenchymal stem cells protect neurons from cardiac arrest-induced pyroptosis

Cardiac arrest can lead to severe neurological impairment as a result of inflammation,mitochondrial dysfunction,and post-cardiopulmonary resuscitation neurological damage.Hypoxic preconditioning has been shown to improve migration and survival of bone marrow–derived mesenchymal stem cells and reduce pyroptosis after cardiac arrest,but the specific mechanisms by which hypoxia-preconditioned bone marrow–derived mesenchymal stem cells protect against brain injury after cardiac arrest are unknown.To this end,we established an in vitro co-culture model of bone marrow–derived mesenchymal stem cells and oxygen–glucose deprived primary neurons and found that hypoxic preconditioning enhanced the protective effect of bone marrow stromal stem cells against neuronal pyroptosis,possibly through inhibition of the MAPK and nuclear factor κB pathways.Subsequently,we transplanted hypoxia-preconditioned bone marrow–derived mesenchymal stem cells into the lateral ventricle after the return of spontaneous circulation in an 8-minute cardiac arrest rat model induced by asphyxia.The results showed that hypoxia-preconditioned bone marrow–derived mesenchymal stem cells significantly reduced cardiac arrest–induced neuronal pyroptosis,oxidative stress,and mitochondrial damage,whereas knockdown of the liver isoform of phosphofructokinase in bone marrow–derived mesenchymal stem cells inhibited these effects.To conclude,hypoxia-preconditioned bone marrow–derived mesenchymal stem cells offer a promising therapeutic approach for neuronal injury following cardiac arrest,and their beneficial effects are potentially associated with increased expression of the liver isoform of phosphofructokinase following hypoxic preconditioning.

Role of octamer transcription factor 4 in proliferation,migration,drug sensitivity,and stemness maintenance of pancreatic cancer cells

BACKGROUND Pancreatic cancer(PC)is one of the most aggressive malignancies characterized by rapid progression and poor prognosis.The involvement of cancer stem cells(CSCs)and Octamer transcription factor 4(OCT4)in PC pathobiology is being increasingly recognized.AIM To investigate the role of OCT4 in pancreatic CSCs and its effect on PC cell prolif-eration,migration,drug sensitivity,and stemness maintenance.METHODS We analyzed OCT4 and CD133 expression in PC tissues and cell lines.BxPC-3 cells were used to assess the effects of OCT4 modulation on cellular behavior.Proliferation,migration,and stemness of BxPC-3 cells were evaluated,and the PI3K/AKT/mTOR pathway was examined to gain mechanistic insights.RESULTS OCT4 and CD133 were significantly overexpressed in PC tissues.OCT4 mo-dulation altered BxPC-3 cell proliferation,invasion,and stemness,with OCT4 overexpression(OV-OCT4)enhancing these properties and OCT4 interference decreasing them.OV-OCT4 activated the PI3K/AKT/mTOR pathway,which correlated with an increase in PC stem cells(PCSC).CONCLUSION OCT4 plays a crucial role in PCSCs by influencing the aggressiveness and drug resistance of PC cells,thus presenting itself as a potential therapeutic target.

Immortalization of epidural fat-derived mesenchymal stem cells: In vitro characterization and adipocyte differentiation potential

BACKGROUND Mesenchymal stem cells(MSCs)are promising candidates for regenerative therapy due to their self-renewal capability,multilineage differentiation potential,and immunomodulatory effects.The molecular characteristics of MSCs are influenced by their location.Recently,epidural fat(EF)and EF-derived MSCs(EF-MSCs)have garnered attention due to their potential benefits to the spinal microenvironment and their high expression of neural SC markers.However,their clinical applications are limited due to cell senescence and limited accessibility of EF.Although many studies have attempted to establish an immortalized,stable SC line,the characteristics of immortalized EF-MSCs remain to be clarified.AIM To establish and analyze stable immortalized EF-MSCs.METHODS The phenotypes of EF-MSCs were analyzed using optical microscopy.Cell immortalization was performed using lentiviral vectors.The biomolecular characteristics of the cells were analyzed by immunoblotting,quantitative PCR,and proteomics.RESULTS The immortalized EF-MSCs demonstrated a significantly extended lifespan compared to the control group,with well-preserved adipogenic potential and SC surface marker expression.Introduction of human telomerase reverse transcriptase genes markedly increased the lifespan of EF-MSCs.Proteomics analysis revealed substantial increase in the expression of DNA replication pathway components in immortalized EF-MSCs.CONCLUSION Immortalized EF-MSCs exhibited significantly enhanced proliferative capacity,retained adipogenic potential,and upregulated the expression of DNA replication pathway components.

Microvesicles derived from mesenchymal stem cells: A promising therapeutic strategy for acute respiratory distress syndrome-related pulmonary fibrosis?

Pulmonary fibrosis significantly contributes to the pathogenesis of acute respiratory distress syndrome(ARDS),markedly increasing patient mortality.Despite the established anti-fibrotic effects of mesenchymal stem cells(MSCs),numerous challenges hinder their clinical application.A recent study demon-strated that microvesicles(MVs)from MSCs(MSC-MVs)could attenuate ARDS-related pulmonary fibrosis and enhance lung function via hepatocyte growth factor mRNA transcription.This discovery presents a promising strategy for managing ARDS-associated pulmonary fibrosis.This article initially examines the safety and efficacy of MSCs from both basic science and clinical perspectives,subsequently exploring the potential and obstacles of employing MSC-MVs as a novel therapeutic approach.Additionally,it provides perspectives on future research into the application of MSC-MVs in ARDS-associated pulmonary fi-brosis.

Bone marrow mesenchymal stem cells promote uterine healing by activating the PI3K/AKT pathway and modulating inflammation in rat models

BACKGROUND Uterine injury can cause uterine scarring,leading to a series of complications that threaten women’s health.Uterine healing is a complex process,and there are currently no effective treatments.Although our previous studies have shown that bone marrow mesenchymal stem cells(BMSCs)promote uterine damage repair,the underlying mechanisms remain unclear.However,exploring the specific regulatory roles of BMSCs in uterine injury treatment is crucial for further understanding their functions and enhancing therapeutic efficacy.AIM To investigate the underlying mechanism by which BMSCs promote the process of uterine healing.METHODS In in vivo experiments,we established a model of full-thickness uterine injury and injected BMSCs into the uterine wound.Transcriptome sequencing was per-formed to determine the enrichment of differentially expressed genes at the wound site.In in vitro experiments,we isolated rat uterine smooth muscle cells(USMCs)and cocultured them with BMSCs to observe the interaction between BMSCs and USMCs in the microenvironment.RESULTS We found that the differentially expressed genes were mainly related to cell growth,tissue repair,and angiogenesis,while the phosphoinositide 3-kinase(PI3K)/protein kinase B(AKT)pathway was highly enriched.Quantitative reverse-transcription polymerase chain reaction was used to validate differentially expressed genes,and the results demonstrated that BMSCs can upregulate genes related to regeneration and downregulate genes related to inflammation.Coculturing BMSCs promoted the migration and proliferation of USMCs,and the USMC microenvironment promoted the myogenic differentiation of BMSCs.Finally,we validated the PI3K/AKT pathway in tissues and cells and showed that BMSCs activate the PI3K/AKT pathway to promote the regeneration of uterine smooth muscle both in vivo and in vitro.CONCLUSION BMSCs upregulated uterine wound regeneration and anti-inflammatory factors and enhanced uterine smooth muscle proliferation through the PI3K/AKT pathway both in vivo and in vitro.

Advances in human umbilical cord mesenchymal stem cells-derived extracellular vesicles and biomaterial assemblies for endometrial injury treatment

Endometrial injury caused by repeated uterine procedures,infections,inflammation,or uterine artery dysfunction can deplete endometrial stem/progenitor cells and impair regeneration,thereby diminishing endometrial receptivity and evidently lowering the live birth,clinical pregnancy,and embryo implantation rates.Currently,safe and effective clinical treatment methods or gene-targeted therapies are unavailable,especially for severe endometrial injury.Umbilical cord mesenchymal stem cells and their extracellular vesicles are characterized by their simple collection,rapid proliferation,low immunogenicity,and tumorigenicity,along with their involvement in regulating angiogenesis,immune response,cell apoptosis and proliferation,inflammatory response,and fibrosis,Therefore,these cells and vesicles hold broad potential for application in endometrial repair.This article reviewed recent research on human umbilical cord mesenchymal stem cells as well as their extracellular vesicles in repairing endometrial injury.

The combined application of stem cells and three-dimensional bioprinting scaffolds for the repair of spinal cord injury

Spinal cord injury is considered one of the most difficult injuries to repair and has one of the worst prognoses for injuries to the nervous system.Following surgery,the poor regenerative capacity of nerve cells and the generation of new scars can make it very difficult for the impaired nervous system to restore its neural functionality.Traditional treatments can only alleviate secondary injuries but cannot fundamentally repair the spinal cord.Consequently,there is a critical need to develop new treatments to promote functional repair after spinal cord injury.Over recent years,there have been seve ral developments in the use of stem cell therapy for the treatment of spinal cord injury.Alongside significant developments in the field of tissue engineering,three-dimensional bioprinting technology has become a hot research topic due to its ability to accurately print complex structures.This led to the loading of three-dimensional bioprinting scaffolds which provided precise cell localization.These three-dimensional bioprinting scaffolds co uld repair damaged neural circuits and had the potential to repair the damaged spinal cord.In this review,we discuss the mechanisms underlying simple stem cell therapy,the application of different types of stem cells for the treatment of spinal cord injury,and the different manufa cturing methods for three-dimensional bioprinting scaffolds.In particular,we focus on the development of three-dimensional bioprinting scaffolds for the treatment of spinal cord injury.