O-linkedβ-N-acetylglucosaminylation may be a key regulatory factor in promoting osteogenic differentiation of bone marrow mesenchymal stromal cells

Cumulative evidence suggests that O-linkedβ-N-acetylglucosaminylation(OGlcNAcylation)plays an important regulatory role in pathophysiological processes.Although the regulatory mechanisms of O-GlcNAcylation in tumors have been gradually elucidated,the potential mechanisms of O-GlcNAcylation in bone metabolism,particularly,in the osteogenic differentiation of bone marrow mesenchymal stromal cells(BMSCs)remains unexplored.In this study,the literature related to O-GlcNAcylation and BMSC osteogenic differentiation was reviewed,assuming that it could trigger more scholars to focus on research related to OGlcNAcylation and bone metabolism and provide insights into the development of novel therapeutic targets for bone metabolism disorders such as osteoporosis.

Senescent mesenchymal stem/stromal cells in pre-metastatic bone marrow of untreated advanced breast cancer patients

Breast cancer is the predominant form of carcinoma among women worldwide,with 70%of advanced patients developing bone metastases,with a high mortality rate.In this sense,the bone marrow(BM)mesenchymal stem/stromal cells(MSCs)are critical for BM/bone homeostasis,and failures in their functionality,transform the BM into a premetastatic niche(PMN).We previously found that BM-MSCs from advanced breast cancer patients(BCPs,infiltrative ductal carcinoma,stage III-B)have an abnormal profile.This work aims to study some of the metabolic and molecular mechanisms underlying MSCs shift from a normal to an abnormal profile in this group of patients.A comparative analysis was undertaken,which included self-renewal capacity,morphology,proliferation capacity,cell cycle,reactive oxygen species(ROS)levels,and senescence-associatedβ‑galactosidase(SA‑β‑gal)staining of BMderived MSCs isolated from 14 BCPs and 9 healthy volunteers(HVs).Additionally,the expression and activity of the telomerase subunit TERT,as well as telomere length,were measured.Expression levels of pluripotency,osteogenic,and osteoclastogenic genes(OCT-4,SOX-2,M-CAM,RUNX-2,BMP-2,CCL-2,M-CSF,and IL-6)were also determined.The results showed that MSCs from BCPs had reduced,self-renewal and proliferation capacity.These cells also exhibited inhibited cell cycle progression and phenotypic changes,such as an enlarged and flattened appearance.Additionally,there was an increase in ROS and senescence levels and a decrease in the functional capacity of TERT to preserve telomere length.We also found an increase in pro-inflammatory/pro-osteoclastogenic gene expression and a decrease in pluripotency gene expression.We conclude that these changes could be responsible for the abnormal functional profile that MSCs show in this group of patients.

Constitutive aryl hydrocarbon receptor facilitates the regenerative potential of mouse bone marrow mesenchymal stromal cells

BACKGROUND Bone marrow mesenchymal stromal cells(BMSCs)are the commonly used seed cells in tissue engineering.Aryl hydrocarbon receptor(AhR)is a transcription factor involved in various cellular processes.However,the function of constitutive AhR in BMSCs remains unclear.AIM To investigate the role of AhR in the osteogenic and macrophage-modulating potential of mouse BMSCs(mBMSCs)and the underlying mechanism.METHODS Immunochemistry and immunofluorescent staining were used to observe the expression of AhR in mouse bone marrow tissue and mBMSCs.The overexpression or knockdown of AhR was achieved by lentivirus-mediated plasmid.The osteogenic potential was observed by alkaline phosphatase and alizarin red staining.The mRNA and protein levels of osteogenic markers were detected by quantitative polymerase chain reaction(qPCR)and western blot.After coculture with different mBMSCs,the cluster of differentiation(CD)86 and CD206 expressions levels in RAW 264.7 cells were analyzed by flow cytometry.To explore the underlying molecular mechanism,the interaction of AhR with signal transducer and activator of transcription 3(STAT3)was observed by co-immunoprecipitation and phosphorylation of STAT3 was detected by western blot.RESULTS AhR expressions in mouse bone marrow tissue and isolated mBMSCs were detected.AhR overexpression enhanced the osteogenic potential of mBMSCs while AhR knockdown suppressed it.The ratio of CD86+RAW 264.7 cells cocultured with AhR-overexpressed mBMSCs was reduced and that of CD206+cells was increased.AhR directly interacted with STAT3.AhR overexpression increased the phosphorylation of STAT3.After inhibition of STAT3 via stattic,the promotive effects of AhR overexpression on the osteogenic differentiation and macrophage-modulating were partially counteracted.CONCLUSION AhR plays a beneficial role in the regenerative potential of mBMSCs partially by increasing phosphorylation of STAT3.

Preliminary delivery efficiency prediction of nanotherapeutics into crucial cell populations in bone marrow niche

Several crucial stromal cell populations regulate hematopoiesis and malignant diseases in bone marrow niches.Precise regulation of these cell types can remodel niches and develop new therapeutics.Multiple nanocarriers have been developed to transport drugs into the bone marrow selectively.However,the delivery efficiency of these nanotherapeutics into crucial niche cells is still unknown,and there is no method available for predicting delivery efficiency in these cell types.Here,we constructed a three-dimensional bone marrow niche composed of three crucial cell populations:endothelial cells(ECs),mesenchymal stromal cells(MSCs),and osteoblasts(OBs).Mimetic niches were used to detect the cellular uptake of three typical drug nanocarriers into ECs/MSCs/OBs in vitro.Less than 5%of nanocarriers were taken up by three stromal cell types,and most of themwere located in the extracellular matrix.Delivery efficiency in sinusoidal ECs,arteriole ECs,MSCs,and OBs in vivo was analyzed.The correlation analysis showed that the cellular uptake of three nanocarriers in crucial cell types in vitro is positively linear correlated with its delivery efficiency in vivo.The delivery efficiency into MSCs was remarkably higher than that into ECs and OBs,no matterwhat kind of nanocarrier.The overall efficiency into sinusoidal ECswas greatly lower than that into arteriole ECs.All nanocarriers were hard to be delivered into OBs(<1%).Our findings revealed that cell tropisms of nanocarriers with different compositions and ligand attachments in vivo could be predicted via detecting their cellular uptake in bone marrow niches in vitro.This study provided the methodology for niche-directed nanotherapeutics development.

Bone Marrow Stromal Cells Express Neural Phenotypes in vitro and Migrate in Brain After Transplantation in vivo

Objective To investigate the differentiation of bone marrow stromal cells （BMSC） into neuron-like cells and to explore their potential use for neural transplantation. Methods BMSC from rats and adult humans were cultured in serum-containing media. Salvia miltiorrhiza was used to induce human BMSC （hBMSC） to differentiate. BMSC were identified with immunocytochemistry. Semi-quantitative RT-PCR was used to examine mRNA expression of neurofilamentl （NF1）, nestin and neuron-specific enolase （NSE） in rat BMSC （rBMSC）. Rat BMSC labelled by Hoschst33258 were transplanted into striatum of rats to trace migration and distribution. Results rBMSC expressed NSE, NFI and nestin mRNA, and NF1 mRNA and expression was increased with induction of Salvia miltiorrhiza. A small number of hBMSC were stained by anti-nestin, anti-GFAP and anti-S 100. Salvia miltiorrhiza could induce hBMSC to differentiate into neuron-like cells. Some differentiated neuron-like cells, that expressed NSE, beta-tubulin and NF-200, showed typical neuron morphology, but some neuron-like cells also expressed alpha smooth muscle protein, making their neuron identification complicated, rBMSC could migrate and adapted in the host brains after being transplanted. Conclusion Bone marrow stromal cells could express phenotypes of neurons, and Salvia milliorrhiza could induce hBMSC to differentiate into neuron-like cells, If BMSC could be converted into neurons instead of mesenchymal derivatives, they would be an abundant and accessible cellular source to treat a variety of neurological diseases.

Glial cell-derived neurotrophic factor mRNA expression in a rat model of spinal cord injury following bone marrow stromal cell transplantation

BACKGROUND： Several animal experiments utilizing bone marrow stromal cell （BMSC） transplantation for the treatment of spinal cord injury have proposed a hypothesis that BMSC transplantation effects are associated with increased glial cell-derived neurotrophic factor （GDNF） expression. OBJECTIVE： To confirm the effects of BMSC transplantation on GDNF mRNA expression in rats with spinal cord injury by reverse transcription-polymerase chain reaction （RT-PCR）. DESIGN, TIME AND SETTING： The present molecular, cell biology experiment was performed at the Key Laboratory of Children＇s Congenital Malformation, Ministry of Health of China ＆ Department of Developmental Biology, Basic Medical College, China Medical University between March 2006 and May 2007. MATERIALS： Sixty healthy Wistar rats aged 2-4-months and of either gender were included in this study. Spinal cord injury was induced in all rats by hemisection of T9 on the left side. RT-PCR kits were purchased from TaKaRa Company, China. Type 9600 RCR amplifier was provided by Perkin Elmer Company, USA. METHODS： Three rats were selected for BMSC culture and subsequent transplantation （after three passages）. Of the remaining 57 rats, nine were selected for sham-operation （sham-operated group）, where only the T9 spinal cord was exposed without hemisection. A total of 48 rats were randomly and evenly divided into BMSC transplantation and model groups. In the BMSC transplantation group, following spinal cord injury induction, each rat was administered a BMSC suspension tbrougb two injection sites selected on the gray and white matter boundary caudally and cephalically, seperately and near to injury site in the spinal cord. The model group received an equal volume of PBS through the identical injection sites. MAIN OUTCOME MEASURES： At 24 and 72 hours, as well as at 7 days, following spinal cord injury, the spinal cord at the T9 segment was removed. Eight rats were allocated to each time point in the BMSC transplantation and model groups, with three rats allocated to the sham-operated group. GDNF mRNA expression was semiquantitatively analyzed by RT-PCR. RESULTS： The sham-operated group exhibited extremely low GDNF mRNA expression. GDNF mRNA expression significantly increased at 24 hours after spinal cord injury, reached a peak level at 72 hours, and slowly decreased thereafter. However, it remained higher than normal levels at 7 days （P 〈 0.05）. At all time points following spinal cord injury, GDNF mRNA expression was significantly greater in the BMSC transplantation group than in the model group （P 〈 0.05）. CONCLUSION： Transplantation of BMSCs into the injured spinal cord up-regulated GDNF mRNA expression, thereby promoting repair of the injured spinal cord.

Cell transplantation for the treatment of spinal cord injury–bone marrow stromal cells and choroid plexus epithelial cells

Transplantation of bone marrow stromal cells （BMSCs） enhanced the outgrowth of regenerating axons and promoted locomotor improvements of rats with spinal cord injury （SCI）. BMSCs did not survive long-term, disappearing from the spinal cord within 2-3 weeks after transplantation. Astrocyte-devoid areas, in which no astrocytes or oligodendrocytes were found, formed at the epicenter of the lesion. It was remarkable that numerous regenerating axons extended through such astrocyte-devoid areas. Regenerating axons were associated with Schwann cells embedded in extracellular matrices. Transplantation of choroid plexus epithelial cells （CPECs） also enhanced axonal regeneration and locomotor improvements in rats with SCI. Although CPECs disappeared from the spinal cord shortly after transplantation, an extensive outgrowth of regenerating axons occurred through astrocyte-devoid areas, as in the case of BMSC transplantation. These findings suggest that BMSCs and CPECs secret neurotrophic factors that promote tissue repair of the spinal cord, including axonal regeneration and reduced cavity formation. This means that transplantation of BMSCs and CPECs promotes ＂intrinsic＂ ability of the spinal cord to regenerate. The treatment to stimu- late the intrinsic regeneration ability of the spinal cord is the safest method of clinical application for SCI. It should be emphasized that the generally anticipated long-term survival, proliferation and differentiation of transplanted cells are not necessarily desirable from the clinical point of view of safety.

Millimeter-wave Exposure Promotes the Differentiation of Bone Marrow Stromal Cells into Cells with a Neural Phenotype

This study investigated the ability of millimeter-wave （MMW） to promote the differentiation of bone marrow stromal cells （BMSCs） into cells with a neural phenotype. The BMSCs were primarily cultured. At passage 3, the cells were induced by β-mercaptoethanol （BME） in combination with MMW or BME alone. The expressions of nucleostemin （NS） and neuron-specific enolase （NSE） were detected by immunofluorescent staining and Western blotting respectively to identify the differentiation. The untreated BMSCs predominately expressed NS. After induced by BME and MMW, the BMSCs exhibited a dramatic decrease in NS expression and increase in NSE expression. The differentiation rate of the cells treated with BME and MMW in combination was significantly higher than that of the cells treated with BME alone （P〈0.05）. It was concluded that MMW exposure enhanced the inducing effect of BME on the differentiation of BMSCs into cells with a neural phenotype.

The future of bone marrow stromal cell transplantation for the treatment of spinal cord injury

Bone marrow stromal cell （BMSC） transplantation therapy is a promising approach for treating spinal cord injury （SCI）, based on a number of experimental and clinical reports （Wright et al., 2011）. BMSCs are a source of neuroregenerative somatic stem cells that are without the potential for tumorigenicity. Although clinical studies of autologous BMSC transplantation have been reported in Asia （fiang et al., 2013; Yoon et al., 2007）, in Japan, it is currently an uncommon procedure and highly controversial as well. This perspective paper provides an overview of the clinical effectiveness of BMSC trans- 191antation and a proposal to enhance its use as a viable therapy.

Intra-portal transplantation of bone marrow stromal cells ameliorates liver fibrosis in mice

BACKGROUND: Bone marrow cells can differentiate into hepatocytes in a suitable microenvironment. This study was undertaken to investigate the effects of transplanted bone marrow stromal cells (BMSCs) on liver fibrosis in mice. METHODS: BMSCs were harvested and cultured from male BALB/c mice, then transplanted into female syngenic BALB/c mice via the portal vein. After partial hepatectomy, diethylnitrosamine (DEN) was administered to induce liver fibrosis. Controls received BMSCs and non-supplemented drinking water, the model group received DEN with their water, and the experimental group received BMSCs and DEN. Mice were killed after 3 months, and ALT, AST, hyaluronic acid (HA), and laminin (LN) in serum and hydroxyproline (Hyp) in the liver were assessed. Alpha-smooth muscle actin (alpha-SMA) in the liver was assessed by immunohistochemistry. Bone marrow-derived hepatocytes were identified by fluorescent in situ hybridization (FISH) in liver sections. RESULTS: BMSCs were shown to differentiate into hepatocyte-like phenotypes after hepatocyte growth factor treatment in vitro. Serum ALT, AST, HA, and LN were markedly reduced by transplanted BMSCs. Liver Hyp content and alpha-SMA staining in mice receiving BMSCs were lower than in the model group, consistent with altered liver pathology. FISH analysis revealed the presence of donor-derived hepatocytes in the injured liver after cross-gender mouse BMSC transplantation. After three months, about 10% of cells in the injured liver were bone marrow-derived. CONCLUSION: BMSCs transplanted via the portal vein can convert into hepatocytes to repair liver injury induced by DEN, restore liver function, and reduce liver fibrosis.

Study on the adoption of Schwann Cell Phenotype by Bone Marrow Stromal Cells in vitro and in vivo

To explore the possibilities of bone marrow stromal cells （MSCs） to adopt Schwann cell phenotype in vitro and in vivo in SD rats. Methods MSCs were obtained from tibia and femur bone marrow and cultured in culture flasks. Beta-mercaptoethanol followed by retinoic acid, forskolin, basic-FGF, PDGF and heregulin were added to induce differentiation of MSCs＇. Schwann cell markers, p75, S-100 and GFAP were used to discriminate induced properties of MSCs＇ by immunofluorescent staining. PKH-67-1abelled MSCs were transplanted into the mechanically injured rat sciatic nerve, and laser confocal microscopy was performed to localize the PKH67 labelled MSCs in the injured sciatic nerve two weeks after the operation. Fluorescence PKH67 attenuation rule was evaluated by flow cytometry in vitro. Results MSCs changed morphologically into cells resembling primary cultured Schwann cells after their induction in vitro. In vivo, a large number of MSCs were cumulated within the layer of epineurium around the injured nerve and expressed Schwann cell markers, p75, S- 100, and GFAP. Conclusion MSCs are able to support nerve fiber regeneration and re-myelination by taking on Schwann cell function, and can be potentially used as possible substitutable cells for artificial nerve conduits to promote nerve regeneration.

Effects of Panax notoginseng saponins on hydrogen peroxide-induced apoptosis in cultured rabbit bone marrow stromal cells

Objective To investigate the effects of Panax notoginseng saponins(PNS)on hydrogen peroxide(H2O2)-induced apoptosis in cultured rabbit bone marrow stromal cells(BMSCs).Methods BMSCs from 3-month-old New Zealand rabbits were isolated and cultured by the density gradient centrifugation combined with adherent method.The cultured BMSCs were divided into three groups:normal control,H2O2 treatment(100μmol/L),and PNS pretreatment(0.1g/L).Intracellular reactive oxygen species(ROS)levels as the index of oxidative stress were measured by using 2’7’-dichlorodihydrofluorescein diacetate.Flow cytometry was used to observe the apoptosis of BMSCs by staining with annexinV-FITC/PI.The protein expression of Bax in BMSCs was analyzed by Western blotting.Activity of caspase-3 enzyme was measured by spectrofluorometry.Results Pretreatment with PNS significantly decreased intracellular ROS level induced by H2O2(P<0.01).PNS markedly attenuated H2O2-induced apoptosis rate from 38.68% to 19.24%(P<0.01).PNS reversed H2O2-induced augmentation of Bax expression.Furthermore,PNS markedly reduced the altered in activity of caspase-3 enzyme induced by H2O2(P<0.01).Conclusion PNS has a protective effect on hydrogen peroxide-induced apoptosis in cultured rabbit BMSCs by scavenging ROS and decreasing Bax expression and caspase-3 activity.

TrkA regulates the regenerative capacity of bone marrow stromal stem cells in nerve grafts

We previously demonstrated that overexpression of tropomyosin receptor kinase A(TrkA)promotes the survival and Schwann celllike differentiation of bone marrow stromal stem cells in nerve grafts,thereby enhancing the regeneration and functional recovery of the peripheral nerve.In the present study,we investigated the molecular mechanisms underlying the neuroprotective effects of TrkA in bone marrow stromal stem cells seeded into nerve grafts.Bone marrow stromal stem cells from Sprague-Dawley rats were infected with recombinant lentivirus vector expressing rat TrkA,TrkA-shRNA or the respective control.The cells were then seeded into allogeneic rat acellular nerve allografts for bridging a 1-cm right sciatic nerve defect.Then,8 weeks after surgery,hematoxylin and eosin staining showed that compared with the control groups,the cells and fibers in the TrkA overexpressing group were more densely and uniformly arranged,whereas they were relatively sparse and arranged in a disordered manner in the TrkA-shRNA group.Western blot assay showed that compared with the control groups,the TrkA overexpressing group had higher expression of the myelin marker,myelin basic protein and the axonal marker neurofilament 200.The TrkA overexpressing group also had higher levels of various signaling molecules,including TrkA,pTrkA(Tyr490),extracellular signal-regulated kinases 1/2(Erkl/2),pErk1/2(Thr202/Tyr204),and the anti-apoptotic proteins Bcl-2 and Bcl-xL.In contrast,these proteins were downregulated,while the pro-apoptotic factors Bax and Bad were upregulated,in the TrkA-shRNA group.The levels of the TrkA effectors Akt and pAkt(Ser473)were not different among the groups.These results suggest that TrkA enhances the survival and regenerative capacity of bone marrow stromal stem cells through upregulation of the Erk/Bcl-2 pathway.All procedures were approved by the Animal Ethical and Welfare Committee of Shenzhen University,China in December 2014(approval No.AEWC-2014-001219).

CHIP regulates bone mass by targeting multiple TRAF family members in bone marrow stromal cells

Carboxyl terminus of Hsp70-interacting protein（CHIP or STUB1） is an E3 ligase and regulates the stability of several proteins which are involved in different cellular functions. Our previous studies demonstrated that Chip deficient mice display bone loss phenotype due to increased osteoclast formation through enhancing TRAF6 activity in osteoclasts. In this study we provide novel evidence about the function of CHIP. We found that osteoblast differentiation and bone formation were also decreased in Chip KO mice. In bone marrow stromal（BMS） cells derived from Chip^-/- mice, expression of a panel of osteoblast marker genes was significantly decreased. ALP activity and mineralized bone matrix formation were also reduced in Chip-deficient BMS cells. We also found that in addition to the regulation of TRAF6, CHIP also inhibits TNFα-induced NF-κB signaling through promoting TRAF2 and TRAF5 degradation. Specific deletion of Chip in BMS cells downregulated expression of osteoblast marker genes which could be reversed by the addition of NF-κB inhibitor. These results demonstrate that the osteopenic phenotype observed in Chip^-/- mice was due to the combination of increased osteoclast formation and decreased osteoblast differentiation. Taken together, our findings indicate a significant role of CHIP in bone remodeling.

Granulocyte-macrophage colony-stimulating factor-transfected bone marrow stromal cells for the treatment of ischemic stroke

Adult, male, Sprague-Dawley rats were injected with granulocyte-macrophage colony-stimulating factor-transfected bone marrow stromal cells （GM-CSF-BMSCs） into the ischemic boundary zone at 24 hours after onset of middle cerebral artery occlusion. Results showed reduced infarct volume, decreased number of apoptotic cells, improved neurological functions, increased angiogenic factor expression, and increased vascular density in the ischemic boundary zone in rats that underwent GM-CSF-BMSCs transplantation compared with the BMSCs group. Experimental findings suggested that GM-CSF-BMSCs could serve as a potential therapeutic strategy for ischemic stroke and are superior to BMSCs alone.

Effects of Panax notoginseng saponins on apoptosis induced by hydrogen peroxide in cultured rabbit bone marrow stromal cells via altering the oxidative stress level and down-regulating caspase-3

Objective： To investigate the effects of Panax notoginseng saponins （PNS） on hydrogen peroxide （H2O2）-induced apoptosis in cultured rabbit bone marrow stromal cells （BMSCs）. Methods： The effects of different concentrations of PNS on proliferation and early osteoblast differentiation of BMSCs were determined by the MTT assay and an alkaline phosphatase （ALP） assay. An optimal effective concentration of PNS was determined and used in subsequent experiments. The cultured BMSCs were divided into three groups： untreated control, H2O2 treated, and PNS pretreatment of H2O2 treated. The oxidative stress level was assessed by superoxide dismutase （SOD） and malondialdehyde （MDA） assays. Flow cytometry was used to determine BMSC apoptosis by staining with annexinV-FITC/propidium iodide （PI）. The activity of caspase-3 enzyme was measured by spectrofluorometry. Results： PNS （0.1g/L） significantly increased both BMSC proliferation rate and ALP activity, while it decreased the indicators of oxidative stress, caspase-3 activity, and the apoptosis rate of BMSCs induced by H2O2.. Conclusion： PNS, acting as a biological antioxidant, had a protective effect on H2O2-induced apoptosis in cultured rabbit BMSCs by decreasing oxidative stress and down-regulating caspase-3.

Co-transplantation of Schwann cells and bone marrow stromal cells versus single cell transplantation on repairing hemisected spinal cord injury of rats

BACKGROUND： Bone marrow stromal cells （BMSCs） or Schwann cells （SCs） transplantation alone can treat spinal cord injury. However, the transplantation either cell-type alone has disadvantages. The co-transplantation of both cells may benefit structural reconstruction and functional recovery of spinal nerves. OBJECTIVE： To verify spinal cord repair and related mechanisms after co-transplantation of BMSCs and SCs in a rat model of hemisected spinal cord injury. DESIGN, TIME AND SETTING： A randomized, controlled, animal experiment was performed at the Department of Histology and Embryology, Mudanjiang Medical College from January 2008 to May 2009. MATERIALS： Rabbit anti-S-100, glial fibrillary acidic protein, neuron specific enolase and neurofilament-200 monoclonal antibodies were purchased from Sigma, USA. METHODS： A total of 100 Wistar rats were used in a model of hemisected spinal cord injury. The rats were randomly assigned to vehicle control, SCs transplantation, BMSCs transplantation, and co-transplantation groups; 25 rats per group. At 1 week after modeling, SCs or BMSCs cultured in vitro were labeled and injected separately into the hemisected spinal segment of SCs and BMSCs transplantation groups through three injection points [5 μL （1 x 107 cells/mL）] cell suspension in each point）. In addition, a 15 μL 1 × 10^7 cells/mL SCs suspension and a 15 μL 1 × 10^7 cells/mL BMSC suspension were injected into co-transplantation group by the above method. MAIN OUTCOME MEASURES： The Basso-Beattie-Bresnahan （BBB） locomotor rating scale and somatosensory evoked potential （SEP） tests were used to assess the functional recovery of rat hind limbs following operation. Structural repair of injured nerve tissue was observed by light microscopy, electron microscopy, immunohistochemistry, and magnetic resonance imaging （MRI）. In vivo differentiation, survival and migration of BMSCs were evaluated by immunofluorescence. RESULTS： BBB scores were significantly greater in all three transplantation groups compared with vehicle control group 8 weeks after transplantation. In particular, the co-transplantation group displayed the highest scores among the groups （P 〈 0.05）. Moreover, recovery of SEP latency and amplitude was observed in all the transplantation groups, particularly after 8 weeks. Again, the co-transplantation group exhibited the greatest improvement （P 〈 0.05）. In the co-transplantation group, imaging showed a smooth surface and intact inner structure at the injury site, with no scar formation, and a large number of orderly cells at the injured site. Axonal regeneration, new myelination, and a large amount of cell division were detected in the co-transplantation group by electron microscopy. Neuron specific enolase （NSE）- and glial fibriilary acidic protein （GFAP）-positive cells were observed in the spinal cord sections 1 week following co-transplantation by immunofluorescence staining. CONCLUSION： Co-transplantation of SCs and BMSCs effectively promoted functional recovery of injured spinal cord in rats compared with SCs or BMSCs transplantation alone. This repair effect is probably achieved because of neuronal-like cells derived from BMSCs to supplement dead neurons in vivo.

Tissue Extracts From Infarcted Myocardium of Rats in Promoting the Differentiation of Bone Marrow Stromal Cells Into Cardiomyocyte-like Cells

Objective To investigate whether cardiac tissue extracts from rats could mimic the cardiac microenvironment and act as a natural inducer in promoting the differentiation of bone marrow stromal cells （BMSCs） into cardiomyocytes. Methods Three kinds of tissue extract or cell lysate [infarcted myocardial tissue extract （IMTE）, normal myocardial tissue extract （NMTE） and cultured neonatal myocardial lysate （NML）] were employed to induce BMSCs into cardiomyocyte-like cells. The cells were harvested at each time point for reverse transcription-polymerase chain reaction （RT-PCR） detection, immunocytochemical analysis, and transmission electron microscopy. Results After a 7-day induction, BMSCs were enlarged and polygonal in morphology. Myofilaments, striated sarcomeres, Z-lines, and more mitochondia were observed under transmission electron microscope. Elevated expression levels of cardiac-specific genes and proteins were also confirmed by RT-PCR and immunocytochemistry. Moreover, IMTE showed a greater capacity of differentiating BMSCs into cardiomyocyte-like cells. Conclusions Cardiac tissue extracts, especially IMTE, can effectively differentiate BMSCs into cardiomyocyte-like cells.

In vitro differentiation of adipose-derived stem cells and bone marrow-derived stromal stem cells into neuronal-like cells

Adipose-derived stem cells and bone marrow-derived stromal stem cells were co-cultured with untreated or Aβ1-40-treated PC12 cells, or grown in supernatant derived from untreated or Aβ1-40-treated PC12 cells. Analysis by western blot and quantitative real-time PCR showed that protein levels of Nanog, Oct4, and Sox2, and mRNA levels of miR/125a/3p were decreased, while expression of insulin-like growth factor-2 and neuron specific enolase was increased. In comparison the generation of neuron specific enolase-positive cells was most successful when adipose-derived stem cells were co-cultured with Aβ1-40-treated PC12 cells. Our results demonstrate that adipose-derived stem cells and bone marrow-derived stromal stem cells exhibit trends of neuronal-like cell differentiation after co-culture with Aβ1-40-treated PC12 cells. This process may relate to a downregulation of miR-125a-3p mRNA expression and increased levels of insulin-like growth factor-2 expression.

Angiogenic Potency of Bone Marrow Stromal Cells Improved by ex Vivo Hypoxia Prestimulation

Summary: To study the angiogenic potency of hypoxia-prestimulated bone marrow stromal cells (BMSCs) when transplanted into acute myocardial infarction models of rats. BMSCs were cultured under hypoxia condition for 24 h. Their expression of VEGF was investigated. The rat acute myocardial infarction models were made by coronary artery ligation and divided into 3 groups at random. In normoxia group, twice-passaged BMSCs were labeled with Bromodeoxyuridine (BrdU) and then implanted into the infarction regions and ischemic border of the recipients in 4 weeks. The rats in hypoxia group were implanted with hypoxia-prestimulated BMSCs. In control group, the model rats received only DMEM medium injection. Six-weeks after AMI, the infarction regions were examined to identify the angiogenesis and the expression of the VEGF. Our results showed that viable cells labeled with BrdU could be identified in the host hearts. The infarction regions in normoxia and hypoxia groups had a greater capillary density and increased VEGF expression than the regions in control group. The capillary density and VEGF expression in hypoxia group were higher than in normoxia group. It is concluded that the enhanced expression of VEGF in BMSCs could be induced by ex vivo hypoxia stimulation. BMSCs implantation promoted the angiogenesis in myocardial infarction tissue via supplying exogenic VEGF. Angiogenic potency of bone marrow stromal cells was improved by ex vivo hypoxia prestimulation though the enhanced VEGF expression.