Cell transplantation therapies for spinal cord injury focusing on bone marrow mesenchymal stem cells:Advances and challenges

Spinal cord injury(SCI)is a devastating condition with complex pathological mechanisms that lead to sensory,motor,and autonomic dysfunction below the site of injury.To date,no effective therapy is available for the treatment of SCI.Recently,bone marrow-derived mesenchymal stem cells(BMMSCs)have been considered to be the most promising source for cellular therapies following SCI.The objective of the present review is to summarize the most recent insights into the cellular and molecular mechanism using BMMSC therapy to treat SCI.In this work,we review the specific mechanism of BMMSCs in SCI repair mainly from the following aspects:Neuroprotection,axon sprouting and/or regeneration,myelin regeneration,inhibitory microenvironments,glial scar formation,immunomodulation,and angiogenesis.Additionally,we summarize the latest evidence on the application of BMMSCs in clinical trials and further discuss the challenges and future directions for stem cell therapy in SCI models.

Protective effect of bone marrow mesenchymal stem cells in intestinal barrier permeability after heterotopic intestinal transplantation

AIM: To explore the protective effect of bone marrow mesenchymal stem cells (BM MSCs) in the small intestinal mucosal barrier following heterotopic intestinal transplantation (HIT) in a rat model.

Effects of heme oxygenase-1-modified bone marrow mesenchymal stem cells on microcirculation and energy metabolism following liver transplantation

AIM To investigate the effects of heme oxygenase-1(HO-1)-modified bone marrow mesenchymal stem cells(BMMSCs)on the microcirculation and energy metabolism of hepatic sinusoids following reduced-size liver transplantation(RLT)in a rat model.METHODS BMMSCs were isolated and cultured in vitro using an adherent method,and then transduced with HO-1-bearing recombinant adenovirus to construct HO-1/BMMSCs.A rat acute rejection model following 50%RLT was established using a two-cuff technique.Recipients were divided into three groups based on the treatment received:normal saline(NS),BMMSCs and HO-1/BMMSCs.Liver function was examined at six time points.The levels of endothelin-1(ET-1),endothelial nitric-oxide synthase(e NOS),inducible nitric-oxide synthase(i NOS),nitric oxide(NO),and hyaluronic acid(HA)were detected using an enzyme-linked immunosorbent assay.The portal vein pressure(PVP)was detected by Power Lab ML880.The expressions of ET-1,i NOS,e NOS,and von Willebrand factor(v WF)protein in the transplanted liver were detected using immunohistochemistry and Western blotting.ATPase in the transplanted liver was detected by chemical colorimetry,and the ultrastructural changes were observed under a transmission electron microscope.RESULTS HO-1/BMMSCs could alleviate the pathological changes and rejection activity index of the transplanted liver,and improve the liver function of rats following 50%RLT,with statistically significant differences compared with those of the NS group and BMMSCs group(P<0.05).In term of the microcirculation of hepatic sinusoids:The PVP on POD7 decreased significantly in the HO-1/BMMSCs and BMMSCs groups compared with that of the NS group(P<0.01);HO-1/BMMSCs could inhibit the expressions of ET-1 and i NOS,increase the expressions of e NOS and inhibit amounts of NO production,and maintain the equilibrium of ET-1/NO(P<0.05);and HO-1/BMMSCs increased the expression of v WF in hepatic sinusoidal endothelial cells(SECs),and promoted the degradation of HA,compared with those of the NS group and BMMSCs group(P<0.05).In term of the energy metabolism of the transplanted liver,HO-1/BMMSCs repaired the damaged mitochondria,and improved the activity of mitochondrial aspartate aminotransferase(ASTm)and ATPase,compared with the other two groups(P<0.05).CONCLUSION HO-1/BMMSCs can improve the microcirculation of hepatic sinusoids significantly,and recover the energy metabolism of damaged hepatocytes in rats following RLT,thus protecting the transplanted liver.

Improvement of neurological function in rats with spinal cord injury after the transplantation of neural stem cells directly differentiated from bone marrow mesenchymal stem cells

Objective To study the effect and mechanism of neurological function recovery in rats with spinal cord injury ( SCI) rats after transplantation of neural stem cells which are directly differentiated from bone marrow mesenchymal stem cells ( BMSC ) ,and to investigate the suitable engraftment time. Methods BMSC at 3rd passage were differentiated into neural stem cells ( NSC) , and immunofluorescence staining was used to

Reversal of hyperglycemia in diabetic rats by portal vein transplantation of islet-like cells generated from bone marrow mesenchymal stem cells

AIM: To study the capacity of bone marrow mesenchymal stem cells (BM-MSCs) trans-differentiating into islet-like cells and to observe the effect of portal vein transplantation of islet-like cells in the treatment of streptozotocin-induced diabetic rat. METHODS: BM-MSCs were isolated from SD rats and induced to differentiate into islet-like cells under defined conditions. Differentiation was evaluated with electron microscopy, RT-PCR, immunofluorescence and flow cytometry. insulin release after glucose challenge was tested with ELiSA. Then allogeneic islet-like cells were transplanted into diabetic rats via portal vein. Blood glucose levels were monitored and islet hormones were detected in the liver and pancreas of the recipient by immunohistochemistry. RESULTS: BM-MSCs were spheroid adherent monolayers with high CD90, CD29 and very low CD45 expression. Typical islet-like cells clusters were formed after induction. Electron microscopy revealed that secretory granules were densely packed within the cytoplasm of the differentiated cells. The spheroid cells expressed islet related genes and hormones. The insulin-positive cells accounted for 19.8% and mean fluorescence intensity increased by 2.6 fold after induction. The cells secreted a small amount of insulin that was increased 1.5 fold after glucose challenge. After transplantation, islet-like cells could locate in the liver expressing islet hormones and lower the glucose levels of diabetic rats during d 6 to d 20.CONCLUSION: Rat BM-MSCs could be transdifferentiated into islet-like cells in vitro . Portal vein transplantation of islet-like cells could alleviate the hyperglycemia of diabetic rats.

Intravenous transplantation of bone marrow mesenchymal stem cells promotes neural regeneration after traumatic brain injury

To investigate the supplement of lost nerve cells in rats with traumatic brain injury by intravenous administration of allogenic bone marrow mesenchymal stem cells, this study established a Wistar rat model of traumatic brain injury by weight drop impact acceleration method and administered 3 × 106 rat bone marrow mesenchymal stem cells via the lateral tail vein. At 14 days after cell transplantation, bone marrow mesenchymal stem cells differentiated into neurons and astrocytes in injured rat cerebral cortex and rat neurological function was improved significantly. These findings suggest that intravenously administered bone marrow mesenchymal stem cells can promote nerve cell regeneration in injured cerebral cortex, which supplement the lost nerve cells.

Effect of intravenous transplantation of bone marrow mesenchymal stem cells on neurotransmitters and synapsins in rats with spinal cord injury

Bone marrow mesenchymal stem cells were isolated, purified and cultured in vitro by Percoll density gradient centrifugation combined with the cell adherence method. Passages 3 5 bone marrow mesenchymal stem cells were transplanted into rats with traumatic spinal cord injury via the caudal vein. Basso-Beattie-Bresnahan scores indicate that neurological function of experimental rats was significantly improved over transplantation time （1-5 weeks）. Expressions of choline acetyltransferase, glutamic acid decarboxytase and synapsins in the damaged spinal cord of rats was significantly increased after transplantation, determined by immunofluorescence staining and laser confocal scanning microscopy. Bone marrow mesenchymal stem cells that had migrated into the damaged area of rats in the experimental group began to express choline acetyltransferase, glutamic acid decarboxylase and synapsins, 3 weeks after transplantation. The Basso-Beattie- Bresnahan scores positively correlated with expression of choline acetyltransferase and synapsins. Experimental findings indicate that intravenously transplanted bone marrow mesenchymal stem cells traverse into the damaged spinal cord of rats, promote expression of choline acetyltransferase, glutamic acid decarboxylase and synapsins, and improve nerve function in rats with spinal cord injury.

Autologous transplantation of bone marrow mesenchymal stem cells on diabetic patients with lower limb ischemia

Objective： To study the efficacy and safety of autologous transplantation of bone marrow mesenchymal stem cells on diabetic patients with lower limb ischemia. Methods： Fifty Type 2 diabetic patients with lower limb ischemia were enrolled and randomized to either transplanted group or control group. Patients in both group received the same conventional treatment. Meanwhile, 20 ml bone marrow from each transplanted patient were collected, and the mesenchymal stem cells were separated by density gradient centrifugation and cultured in the medium with autologous serum. After three-weeks adherent culture in vitro, 7.32×10^8-5.61×10^9 mesenchymal stem cells were harvested and transplanted by multiple intramuscular and hypodermic injections into the impaired lower limbs. Results： At the end of 12-week follow-up, 5 patients were excluded from this study because of clinical worsening or failure of cell culture. Main ischemic symptoms, including rest pain and intermittent claudication, were improved significantly in transplanted patients. The ulcer healing rate of the transplanted group （1 5 of 18, 83.33%） was significantly higher than that of the control group （9 of 20, 45.00%, P=0.012）.The mean of resting ankle-brachial index （ABI） in transplanted group significantly was increased from 0.61±0.09 to 0.74±0.11 （P〈0.001）. Magnetic resonance angiography （MRA） demonstrated that there were more patients whose score of new vessels exceeded or equaled to 2 in the transplant patients （11 of 15） than in control patients （2 of 14, P=0.001）. Lower limb amputation rate was significantly lower in transplanted group than in the control group （P=0.040）. No adverse effects was observed in transplanted group. Conclusion： These results indicate that the autologous transplantation of bone marrow mesenchymal stem cells relieves critical lower limb ischemia and promotes ulcers healing in Type 2 diabetic patients.

Small extracellular vesicles from hypoxia-preconditioned bone marrow mesenchymal stem cells attenuate spinal cord injury via miR-146a-5p-mediated regulation of macrophage polarization

Spinal cord injury is a disabling condition with limited treatment options.Multiple studies have provided evidence suggesting that small extracellular vesicles(SEVs)secreted by bone marrow mesenchymal stem cells(MSCs)help mediate the beneficial effects conferred by MSC transplantation following spinal cord injury.Strikingly,hypoxia-preconditioned bone marrow mesenchymal stem cell-derived SEVs(HSEVs)exhibit increased therapeutic potency.We thus explored the role of HSEVs in macrophage immune regulation after spinal cord injury in rats and their significance in spinal cord repair.SEVs or HSEVs were isolated from bone marrow MSC supernatants by density gradient ultracentrifugation.HSEV administration to rats via tail vein injection after spinal cord injury reduced the lesion area and attenuated spinal cord inflammation.HSEVs regulate macrophage polarization towards the M2 phenotype in vivo and in vitro.Micro RNA sequencing and bioinformatics analyses of SEVs and HSEVs revealed that mi R-146a-5p is a potent mediator of macrophage polarization that targets interleukin-1 receptor-associated kinase 1.Reducing mi R-146a-5p expression in HSEVs partially attenuated macrophage polarization.Our data suggest that HSEVs attenuate spinal cord inflammation and injury in rats by transporting mi R-146a-5p,which alters macrophage polarization.This study provides new insights into the application of HSEVs as a therapeutic tool for spinal cord injury.

A Biological Pacemaker Restored by Autologous Transplantation of Bone Marrow Mesenchymal Stem Cells

Objective：To restore cardiac autonomic pace function by autologous trans- plantation and committed differentiation of hone marrow mesenchymal stern cells, and explore the technique for the treatment of sick sinus syndrome. Methods ： Mesenchymal stern cells isolated from canine bone marrow were culture-expanded and differentiated in vitro by 5-azacytidine. The models of sick sinus syndrome in canines were established by ablating sinus node with radio-frequency technique. Differentiated mesenchymal stem cells labeled by BrdU were autologously transplanted into sinus node area through direct injection. The effects of autologous transplantation of mesenchymal stern cells on cardiac autonomic pace function in sick sinus syndrome models were evaluated by electrocardiography, pathologic and immunohistochemical staining technique. Results：There was distinct improvement on pace function of sick sinus syndrome animal models while differentiated mesenchymal stem cells were auto-transplanted into sinus node area. Mesenchymal stern cells transplanted in sinus node area were differentiated into similar sinus node cells and endothelial cells in vivo, and established gap junction with native cardiomyocytes. Conclusion ： The committed- induced mesenchymal stern cells transplanted into sinus node area can differentiate into a- nalogous sinus node cells and improve pace function in canine sick sinus syndrome models.

Bone marrow mesenchymal stem cells in treatment of peripheral nerve injury

Peripheral nerve injury(PNI)is a common neurological disorder and complete functional recovery is difficult to achieve.In recent years,bone marrow mesenchymal stem cells(BMSCs)have emerged as ideal seed cells for PNI treatment due to their strong differentiation potential and autologous trans-plantation ability.This review aims to summarize the molecular mechanisms by which BMSCs mediate nerve repair in PNI.The key mechanisms discussed include the differentiation of BMSCs into multiple types of nerve cells to promote repair of nerve injury.BMSCs also create a microenvironment suitable for neuronal survival and regeneration through the secretion of neurotrophic factors,extracellular matrix molecules,and adhesion molecules.Additionally,BMSCs release pro-angiogenic factors to promote the formation of new blood vessels.They modulate cytokine expression and regulate macrophage polarization,leading to immunomodulation.Furthermore,BMSCs synthesize and release proteins related to myelin sheath formation and axonal regeneration,thereby promoting neuronal repair and regeneration.Moreover,this review explores methods of applying BMSCs in PNI treatment,including direct cell trans-plantation into the injured neural tissue,implantation of BMSCs into nerve conduits providing support,and the application of genetically modified BMSCs,among others.These findings confirm the potential of BMSCs in treating PNI.However,with the development of this field,it is crucial to address issues related to BMSC therapy,including establishing standards for extracting,identifying,and cultivating BMSCs,as well as selecting application methods for BMSCs in PNI such as direct transplantation,tissue engineering,and genetic engineering.Addressing these issues will help translate current preclinical research results into clinical practice,providing new and effective treatment strategies for patients with PNI.

Effects of interleukin-10 treated macrophages on bone marrow mesenchymal stem cells via signal transducer and activator of transcription 3 pathway

BACKGROUND Alveolar bone defects caused by inflammation are an urgent issue in oral implant surgery that must be solved.Regulating the various phenotypes of macrophages to enhance the inflammatory environment can significantly affect the progression of diseases and tissue engineering repair process.AIM To assess the influence of interleukin-10(IL-10)on the osteogenic differentiation of bone marrow mesenchymal stem cells(BMSCs)following their interaction with macrophages in an inflammatory environment.METHODS IL-10 modulates the differentiation of peritoneal macrophages in Wistar rats in an inflammatory environment.In this study,we investigated its impact on the proliferation,migration,and osteogenesis of BMSCs.The expression levels of signal transducer and activator of transcription 3(STAT3)and its activated form,phos-phorylated-STAT3,were examined in IL-10-stimulated macrophages.Subsequently,a specific STAT3 signaling inhibitor was used to impede STAT3 signal activation to further investigate the role of STAT3 signaling.RESULTS IL-10-stimulated macrophages underwent polarization to the M2 type through substitution,and these M2 macrophages actively facilitated the osteogenic differentiation of BMSCs.Mechanistically,STAT3 signaling plays a crucial role in the process by which IL-10 influences macrophages.Specifically,IL-10 stimulated the activation of the STAT3 signaling pathway and reduced the macrophage inflammatory response,as evidenced by its diminished impact on the osteogenic differentiation of BMSCs.CONCLUSION Stimulating macrophages with IL-10 proved effective in improving the inflammatory environment and promoting the osteogenic differentiation of BMSCs.The IL-10/STAT3 signaling pathway has emerged as a key regulator in the macrophage-mediated control of BMSCs’osteogenic differentiation.

Combined transplantation of bone marrow mesenchymal stem cells and pedicled greater omentum promotes locomotor function and regeneration of axons after spinal cord injury in rats

BACKGROUND： According to previous studies, the neuroprotective effect of the pedicled greater omentum may be attributed to the secretion of neurotrophic factors and stimulation of angiogenesis. The neurotrophic factors released from the pedicled greater omentum, such as brain-derived neurotrophic factor and neurotrophin 3/4/5 could exert a neuroprotective effect on the damaged host neural and glial cells, and also could induce the transdifferentiation of transplanted bone marrow mesenchymal stem cells （BMSCs） into neural cells. OBJECTIVE： Based on the functions of the omentum of neuro-protection and vascularization, we hypothesize that the transplantation of BMSCs and pedicled greater omentum into injured rat spinal cord might improve the survival rate and neural differentiation of transplanted BMSCs and consequently gain a better functional outcome. DESIGN, TIME AND SETFING： A randomized, controlled animal experiment. The experiments were carried out at the Department of Anatomy, the Secondary Military Medical University of Chinese PLA between June 2005 and June 2007. MATERIALS： Fifteen male inbred Wistar rats, weighing （200±20） g, provided by the Experimental Animal Center of the Secondary Military Medical University of Chinese PLA were used and met the animal ethical standards. Mouse anti-BrdU and mouse anti-NF200 monoclonal antibody were purchased from Boster, China. METHODS： Cell culture： We used inbred Sprague-Dawley rats to harvest bone marrow for culture of BMSCs and transplantation to avoid possible immune rejection. BMSCs were cultured via total bone marrow adherence. Experimental grouping and intervention： The rats were randomly divided into a control group, cell group and combined group, five rats per group. Rats in the control group underwent spinal cord injury （SCI） only, during which an artery clamp with pressure force of 30 g was employed to compress the spinal cord at the Tl0 level for 30 seconds to produce the SCI model. 5 μ L PBS containing 10^5 BMSCs was injected into the injured site of the spinal cord in 60 seconds via a microsyringe in the cell group after SCI. In the combined group, after SCI and BMSC transplantation, an autograft pedicled greater omentum was transplanted onto the injured site of the spinal cord and fixed with a suture. SCI model and transplantation： Control group, SCI model without treatment; cell group, transplantation of BMSCs after SCI; combined group, combined transplantation of BMSCs and pedicled greater omentum after SCI. MAIN OUTCOME MEASURES： At days 1, 7, 14, 21 and 28 PO （post operation）, the Basso, Beattie and Bresnahan （BBB） scale was used to observe and evaluate the recovery of locomotor function. At day 29 PO, after transcardial perfusion using 4% paraformaldehyde, a spinal cord segment of 1 cm around the injury was harvested. A cryostat section was performed longitudinally in the horizontal plane and sections were chosen by systematic random sampling for staining. Anti-BrdU staining and counting was performed to measure survival rate of transplanted BMSCs; anti-BrdU-nestin and BrdU-glial fibrillary acidic protein （GFAP） double staining and counting measured neural differentiation of BMSCs; and anti-NF 200 staining was used to evaluate axonal regeneration. RESULTS： All 15 rats were included in the outcome analysis, without any loss. Changes in BBB scores： Combined transplantation of BMSCs and the pedicled greater omentum produced significantly higher BBB scores at 7-28 days post-injury than in the control group （P 〈 0.05）. BBB scores in the cell group were higher than in the control group at 28 days post-injury （P 〈 0.05）. Survival rate and neural differentiation of transplanted BMSCs： Immunostaining of BrdU demonstrated that transplanted BMSCs survived in the spinal cord and migrated cranially and caudally as far as 0.5 mm from the injection site in the cell group and combined group. Some of the transplanted BMSCs expressed nestin or GFAP which revealed neural differentiation of BMSCs in the combined group and cell group. Axonal regeneration： The areas of axonal NF200 staining in the cell group and control group were lower than that of the combined group （P 〈 0.01 ）. CONCLUSION： It is effective and feasible to transplant BMSCs with the pedicled greater omentum for regeneration of spinal cord after SCI compared with transplanting BMSCs alone. This method results in better locomotor outcomes and axonal regeneration.

VEGF-expressing Bone Marrow Mesenchymal Stem Cells Transplantation Improved Heart Function of Myocardial Infarct Rabbits

Objectives To treat myocardial infarction with MSCs transplantation combined with VEGF gene therapy in rabbits and to study its mechanisms. Methods Forty-eight rabbits were randomly divided into MI group （n=12）, MSCs group （n=12）, VEGF group （n=12）, MSCs＋VEGF group （M＋V group, n=12）. Rabbit myocardial infarction models were founded by the ligation of left anterior descending artery. 107 MSCs were injected into the infarct-zone in four sites 2 weeks later in MSCs and M＋ V group, phVEGF gene were injected in infarct-zone in VEGF group and MSCs transfected with phVEGF gene were injected in M＋V group. Heart function including LVEDP, LVSP, LVDP, -dp/dtmax, ＋dp/dtmax, were measured in vivo. The hearts were harvested at 4 weeks after transplantation and sectioned for HE stain, immunohistochemical stain of BrdU and VIII factor antigen. Results The left ventricular hemodynamics parameters showed that heart function were improved more in M＋V group than MSCs group, MI group and VEGF group. The numbers of BrdU positive cells in M＋ V group（61±8）were more than in MSCs group （44±8, P 〈 0.01）. The numbers of vessels in infarcted zone were more in M＋V group （49±8） than in MSCs group （33±6, P 〈 0.01）,VEGF group（30±8, P 〈 0.01）and Mlgroup （18±4, P〈0.01）. Conclusions VEGF-expressing MSCs transplantation could improve heart function after myocardial infarction, and they were more effective than sole MSCs transplantation. Keeping more MSCs survival and ameliorating the blood supply of infarct-zone might be involved in the mechanisms.

Effects of transplantation of human bone marrow mesenchymal stem cells in rats with liver failure

Objective: To investigate the effect of hepatic differentiation of human bone marrow mesenchymal stem cells (HBMSCs) induced in vitro and transplanted into rats with liver failure via portal vein, and observe the changes of liver function and pathological tissue. Method:After passage to the 6th generation in vitro, the hepatic differentiation was induced by HGFand EGF inducible factors. CCL4 acute liver failure model in rats were established, and randomly divided into 5 groups transplanted with differentiated stem cells via portal vein. These five groups included HGF-differentiated HBMSCs transplantation, EGF-differentiated HBMSCs transplantation, EGF+HGF-differentiated HBMSCs transplantation, non-differentiated HBMSCs transplantation, and non-HBMSCs transplantation. Liver function and pathological changes were detected. Results: Rats models survival, serum albumin, aminotransferase and coagulation indexes were observed at 12 h, 72 h, 7 d, 1 month and 2 months after treatment. The results showed that the survival and albumin, aminotransferase and coagulation function of rats were improved significantly after treatment in HGF-differentiated, EGF-differentiated, EGF+HGF-differentiated and non-differentiated transplantation groups, compared tothe non-HBMSCstransplantation group(P<0.05), while no significance was observed in above four groups(P>0.05).Pathological changes was ameliorated in the liver of rat models in HGF-, EGF-, EGF+HGF- and non-differentiated transplantation groups, compared to the non-HBMSCs transplantation group. Conclusion: Liver-differentiated BMSCs transplanted into rats with liver failure could effectively improve liver function and survival rate.

Exosomes from bone marrow mesenchymal stem cells are a potential treatment for ischemic stroke

Exosomes derived from human bone marrow mesenchymal stem cells(MSC-Exo)are characterized by easy expansion and storage,low risk of tumor formation,low immunogenicity,and anti-inflammatory effects.The therapeutic effects of MSC-Exo on ischemic stroke have been widely explored.However,the underlying mechanism remains unclear.In this study,we established a mouse model of ischemic brain injury induced by occlusion of the middle cerebral artery using the thread bolt method and injected MSC-Exo into the tail vein.We found that administration of MSC-Exo reduced the volume of cerebral infarction in the ischemic brain injury mouse model,increased the levels of interleukin-33(IL-33)and suppression of tumorigenicity 2 receptor(ST2)in the penumbra of cerebral infarction,and improved neurological function.In vitro results showed that astrocyte-conditioned medium of cells deprived of both oxygen and glucose,to simulate ischemia conditions,combined with MSC-Exo increased the survival rate of primary cortical neurons.However,after transfection by IL-33 siRNA or ST2 siRNA,the survival rate of primary cortical neurons was markedly decreased.These results indicated that MSC-Exo inhibited neuronal death induced by oxygen and glucose deprivation through the IL-33/ST2 signaling pathway in astrocytes.These findings suggest that MSC-Exo may reduce ischemia-induced brain injury through regulating the IL-33/ST2 signaling pathway.Therefore,MSC-Exo may be a potential therapeutic method for ischemic stroke.

Exosomal miR-23b from bone marrow mesenchymal stem cells alleviates oxidative stress and pyroptosis after intracerebral hemorrhage

Our previous studies showed that miR-23b was downregulated in patients with intracerebral hemorrhage(ICH). This indicates that miR-23b may be closely related to the patho-physiological mechanism of ICH, but this hypothesis lacks direct evidence. In this study, we established rat models of ICH by injecting collagenase Ⅶ into the right basal ganglia and treating them with an injection of bone marrow mesenchymal stem cell(BMSC)-derived exosomal miR-23b via the tail vein. We found that edema in the rat brain was markedly reduced and rat behaviors were improved after BMSC exosomal miR-23b injection compared with those in the ICH groups. Additionally, exosomal miR-23b was transported to the microglia/macrophages, thereby reducing oxidative stress and pyroptosis after ICH. We also used hemin to mimic ICH conditions in vitro. We found that phosphatase and tensin homolog deleted on chromosome 10(PTEN) was the downstream target gene of miR-23b, and exosomal miR-23b exhibited antioxidant effects by regulating the PTEN/Nrf2 pathway. Moreover, miR-23b reduced PTEN binding to NOD-like receptor family pyrin domain containing 3(NLRP3) and NLRP3 inflammasome activation, thereby decreasing the NLRP3-dependent pyroptosis level. These findings suggest that BMSC-derived exosomal miR-23b exhibits antioxidant effects through inhibiting PTEN and alleviating NLRP3 inflammasome-mediated pyroptosis, thereby promoting neurologic function recovery in rats with ICH.

A novel mutation in ROR2 led to the loss of function of ROR2 and inhibited the osteogenic differentiation capability of bone marrow mesenchymal stem cells(BMSCs)

Receptor tyrosine kinase-like orphan receptor 2(ROR2)has a vital role in osteogenesis.However,the mechanism underlying the regulation of ROR2 in osteogenic differentiation is still poorly comprehended.A previous study by our research group showed that a novel compound heterozygous ROR2 variation accounted for the autosomal recessive Robinow syndrome(ARRS).This study attempted to explore the impact of the ROR2:c.904C>T variant specifically on the osteogenic differentiation of BMSCs.Methods:Coimmunoprecipitation(CoIP)-western blotting was carried out to identify the interaction between ROR2 and Wnt5a.Double-immunofluorescence staining was used for determining the expressions and co-localization of ROR2 and Wnt5a in bone marrow mesenchymal stem cells(BMSCs).Western blot(WB)analysis and quantitative reverse transcription polymerase chain reaction(RT-qPCR)were conducted to identify the expression levels of ROR2 in the BMSCs transfected with LV-shROR2 or LV-ROR2-c.904C>T.The alkaline phosphatase(ALP)activity was detected,and Alizarin Red S staining was done for evaluating the osteogenic differentiation of BMSCs.RT-qPCR was employed to identify the expression of the sphingomyelin synthase 1(SMS1)mRNA in the BMSCs transfected with LV-shROR2 or LV-ROR2-c.904C>T and the mRNA expression levels of Runt-related transcription factor 2(RUNX2),osteocalcin(OCN),and osteopontin(OPN).WB was performed to confirm the protein expressions of extracellular regulated protein kinases1(ERK),P-ERK,Smad family member1/5/8(Smad1/5/8),P-Smad1/5/8,P-P38,P38,RUNX2,OCN,and OPN in the BMSCs transfected with LV-shROR2/LV-ROR2-c.904C>T and sphingomyelin(SM).Results:The ROR2:c.904C>T mutant altered the subcellular localization of the ROR2 protein,which caused an impaired interaction between ROR2 and Wnt5a.The depletion of ROR2 restricted the osteogenic differentiation capability of BMSCs and downregulated the expression of SMS1.SM treatment could reverse the inhibition of osteoblastic differentiation in ROR2-depleted BMSCs.Conclusion:The findings of this work revealed that the ROR2:c.904C>T variant led to the loss of function of ROR2,which impaired the interaction between ROR2 and Wnt5a and also controlled the osteogenic differentiation capability of BMSCs.Furthermore,SM was revealed to be engaged in the osteoblastic differentiation of BMSCs regulated by ROR2,which renders SM a potential target in the therapy for ARRS.

Controversies regarding transplantation of mesenchymal stem cells

Mesenchymal stem cells(MSCs)have tantalized regenerative medicine with their therapeutic potential,yet a cloud of controversies looms over their clinical tran-splantation.This comprehensive review navigates the intricate landscape of MSC controversies,drawing upon 15 years of clinical experience and research.We delve into the fundamental properties of MSCs,exploring their unique immuno-modulatory capabilities and surface markers.The heart of our inquiry lies in the controversial applications of MSC transplantation,including the perennial debate between autologous and allogeneic sources,concerns about efficacy,and lingering safety apprehensions.Moreover,we unravel the enigmatic mechanisms surro-unding MSC transplantation,such as homing,integration,and the delicate balance between differentiation and paracrine effects.We also assess the current status of clinical trials and the ever-evolving regulatory landscape.As we peer into the future,we examine emerging trends,envisioning personalized medicine and innovative delivery methods.Our review provides a balanced and informed perspective on the controversies,offering readers a clear understanding of the complexities,challenges,and potential solutions in MSC transplantation.

Exploring the Mechanism of CircRNA-vgll3 in Osteogenically Differentiated Human Bone Marrow Mesenchymal Stem Cells

Objective:To explore the mechanism of circRNA-vgll3 in osteogenic differentiation of human bone marrow mesenchymal stem cells.Methods:BMSCs cells were transfected with circRNA-vgll3,and divided into circRNA-vgll3 high-level group,circRNA-vgll3 low-level group,and negative control group(circRNA-vgll3 not transfected)according to the amount of transfection.The proliferation and apoptosis of BMSCs osteoblasts in each group were analyzed,and the alkaline phosphatase(ALP)activity,type I collagen gray value,bone morphogenetic protein 2(BMP-2),Runx2 protein,and mRNA expression levels were detected.Results:The circRNA-vgll3 low-level group had a significant inhibitory effect on the proliferation of BMSCs osteoblasts,and the apoptosis rate of the circRNA-vgll3 low-level group was significantly higher than that of the circRNA-vgll3 high-level group(P<0.05);ALP activity,type I collagen gray value,BMP-2,Runx2 protein,and mRNA expression levels in the high-level circRNA-vgll3 group were significantly higher than those in the low-level circRNA-vgll3 group,and the difference was statistically significant(P<0.05).Conclusion:Overexpression of circRNA-vgll3 can promote the osteogenic differentiation ability of BMSCs,while low expression of circRNA-vgll3 can inhibit the osteogenic differentiation ability of BMSCs.The main mechanism of action is that circRNA-vgll3 can affect osteogenic differentiation by regulating the Runx2 protein.