Rat BM-MSCs Research Articles

MiR-29a-3p in Exosomes from Heme Oxygenase-1 Modified Bone Marrow Mesenchymal Stem Cells Alleviates Steatotic Liver Ischemia-Reperfusion Injury in Rats by Suppressing Ferroptosis via Iron Responsive Element Binding Protein 2

Hepatic ischemia-reperfusion injury (IRI) is an inevitable result of liver surgery. Steatotic livers are extremely sensitive to IRI and have worse tolerance. Ferroptosis is considered to be one of the main factors of organ IRI. This study is aimed at exploring the role of ferroptosis in the effect of heme oxygenase-1-modified bone marrow mesenchymal stem cells (HO-1/BMMSCs) on steatotic liver IRI and its mechanism. An IRI model of a steatotic liver and a hypoxia reoxygenation (HR) model of steatotic hepatocytes (SHPs) were established. Rat BMMSCs were extracted and transfected with the Ho1 gene to establish HO-1/BMMSCs, and their exosomes were extracted by ultracentrifugation. Ireb2 was knocked down to verify its role in ferroptosis and cell injury in SHP-HR. Public database screening combined with quantitative real-time reverse transcription PCR identified microRNAs (miRNAs) targeting Ireb2 in HO-1/BMMSCs exosomes. miR-29a-3p mimic and inhibitor were used for functional verification experiments. Liver function, histopathology, terminal deoxynulceotidyl transferase nick-end-labeling staining, cell viability, mitochondrial membrane potential, and cell death were measured to evaluate liver tissue and hepatocyte injury. Ferroptosis was assessed by detecting the levels of IREB2, Fe2+, malondialdehyde, glutathione, lipid reactive oxygen species, glutathione peroxidase 4, prostaglandin-endoperoxide synthase 2 mRNA, and mitochondrial morphology. The results revealed that HO-1/BMMSCs improved liver tissue and hepatocyte injury and suppressed ferroptosis in vivo and in vitro. The expression of IREB2 was increased in steatotic liver IRI and SHP-HR. Knocking down Ireb2 reduced the level of Fe2+ and inhibited ferroptosis. HO-1/BMMSC exosomes reduced the expression of IREB2 and inhibited ferroptosis and cell damage. Furthermore, we confirmed high levels of miR-29a-3p in HO-1/BMMSCs exosomes. Overexpression of miR-29a-3p downregulated the expression of Ireb2 and inhibited ferroptosis. Downregulation of miR-29a-3p blocked the protective effect of HO-1/BMMSC exosomes on SHP-HR cell injury. In conclusion, ferroptosis plays an important role in HO-1/BMMSC-mediated alleviation of steatotic liver IRI. HO-1/BMMSCs could suppress ferroptosis by targeting Ireb2 via the exosomal transfer of miR-29a-3p.

Peptide hormone ELABELA promotes rat bone marrow-derived mesenchymal stem cell proliferation and migration by manipulating the cell cycle through the PI3K/AKT pathway under the hypoxia and ischemia microenvironment

BackgroundMesenchymal stem cells (MSCs) are emerging as a potential candidate for stem cell transplantation to repair myocardial tissue in myocardial infarctions (MI). However, there are some pivotal limitations such as poor survival and low migration capacity of MSCs in hypoxic and ischemic microenvironments of MI. Our previous work verified that ELABELA (also abbreviated as ELA), a peptide hormone, could play a role as a growth factor and prolong the life span of rat bone marrow-derived mesenchymal stem cells (RAT BM-MSCs) under hypoxic and ischemic conditions. Nevertheless, the influence of ELA on the cell cycle, proliferation, and migration remains elusive. This study will further explore the improvement of the biological functions of ELA-treated RAT BM-MSCs, so as to provide a reference for improving the efficacy of RAT BM-MSCs in MI.MethodsRat BM-MSCs were isolated from 80 to 120 g Sprague Dawley rats by flushing femurs and tibias under the aseptic condition. RAT BM-MSCs of the third passage were divided into control group, hypoxic/ischemic (H/I) group, ELA group, ELA-LY group and LY group. RAT BM-MSCs were cultured under normoxia in control group. In H/I group, RAT BM-MSCs were exposed to hypoxia (1% O2) and serum deprivation for 24 h. RAT BM-MSCs in ELA group were treated with 5 µM ELA prior to the H/I exposure for 24 h. The PI3K/AKT inhibitor, LY294002 (50 µM), was used in ELA-LY group and LY group to observe the effect of ELA on PI3K/AKT activation. Cell proliferation ability was examined by CCK-8. Cell cycle was assessed with flow cytometry. Cell migration was evaluated by Transwell assay. Expression levels of total-AKT, phosphorylated-AKT, and cell cycle-associated proteins were examined by Western blotting.ResultsELA-treated RAT BM-MSCs exhibited significantly higher proliferation ability, cell viability, and migration under H/I conditions. The cell cycle analysis showed that an increased proportion of cells in the S and G2/M phases of the cell cycle were observed in ELA-treated RAT BM-MSCs. The addition of ELA activated the PI3K/AKT signaling pathway. Additionally, upon treating with the inhibitor of the PI3K/AKT signaling pathway, ELA-triggered proliferation, cell viability, and migration were abrogated.ConclusionsELA can be used to enhance the proliferation ability, cell viability, and migration of RAT BM-MSCs through the PI3K/AKT signaling pathway and alleviate cell cycle arrest at the G0/G1 phase under hypoxic and ischemic injury. Thus, this study provides a promising strategy that ELA may help to optimize the mesenchymal stem cell-based therapy in MI.

Bone Regeneration by Homeopathic Symphytum officinale

Cell therapy has been proposed as an effective treatment method for bone regeneration using stem cells and osteogenic inducting mediators. In the present study, the ability of homeopathic remedy Symphytum officinale to induce osteogenic differentiation of rat bone marrow-derived mesenchymal stem cells (rat BM-MSCs) was studied MSCs were isolated from the rat’s bone morrow. Cytotoxic effect of Symphytum on the MSCs was evaluated by MTT assay. The osteogenic induction ability of Symphytum has been assessed by alizarin red staining (ALZ) and quantitative alkaline phosphatase (ALP) activity assays and compared with the osteogenic standard medium. MTT assay results illustrated that Symphytum 200 C had a high cytotoxicity (to about 75.2 ± 3.12), so that lower potencies were used for the next experiments. Symphytum 6 C had the most color intensity in ALZ and ALP staining assays. Also, quantitative analyses of ALP activity revealed that Symphytum 6 C caused the most increase in the ALP activity up to 4.04 ± 0.34 and 7.86 ± 1.38 on day 7 and 21, respectively. According to this finding, Symphytum could enhance osteogenic differentiation of MSCs and can be considered as a safe, low cost, and highly effective drug for bone regeneration. Cell therapy has been proposed as an effective treatment method for bone regeneration using stem cells and osteogenic inducting mediators. In the present study, the ability of homeopathic remedy Symphytum officinale to induce osteogenic differentiation of rat bone marrow-derived mesenchymal stem cells (rat BM-MSCs) was studied. The results illustrated that Symphytum 6 C had the most osteogenic induction effect compare with osteogenic standard medium. According to this finding, Symphytum officinale as a natural compound can significantly induce osteogenic differentiation of rat BM-MSCs. So, it could be considered as a safe and more cost-effective therapeutic agent for clinical treatment of bone disorders.

Comparative Study on Effect of Mesenchymal Stem Cells and Endothelial Progenitor Cells on Treatment of Experimental CCL4 Induced Liver Fibrosis

Abstract Background Bone marrow mesenchymal stem cells (BM-MSCs) and human umbilical cord endothelial progenitor cells (UC-EPCs) have several benefits for liver regeneration. We speculate huge impacts of rat BM-MSCs and UC-EPCs on reversal of hepatic injury and improvement of liver function in liver fibrosis induced by carbon tetrachloride (CCl4). Methods Forty adult rats were divided into 4 groups; control group, CCl4 group, CCl4/BM-MSCs group and CCl4/UCEPCs group. Blood samples were driven from rats at 1, 2 and 3months to measure serum concentration of albumin and alanine aminotransferase (ALT). Quantitative expression of HGF,TGF-β, MMP-2, and VEGF were assessed by polymerase chain reaction. Histological examination of the liver tissue was performed. α-SMA immunohistochemistry to identify the myoepithelial cells (MECs) and Ki-67 to identify cell prolifration immunohistochemistry are detected in groups injected with cells to confirm cells regeneration. Results Regarding liver function, there was elevating albumin (P < 0.05) and reducing ALT (P < 0.05) concentrations in groups treated with BM-MSCs and UC-EPCs effect compared to untreated CCL4 group. Concerning gene expression, UC-EPCs treated group have significantly higher MMP-2 and VEGF (P < 0.01) genes expression than BM-MSCs treated group. Furthermore, UC-EPCs were more valuable than BM-MSCs in increasing gene expression of HGF (P < 0.05) and immunohistochemistry of α-SMA and Ki-67 (P < 0.01). BM-MSCs have significantly lower TGF- β (P < 0.00) compared to UC-EPCs. Conclusion This study highlighted on liver regeneration role of both human UC-EPCs and BM-MSCs in liver fibrosis by different signaling mechanistic.

Bone marrow-mesenchymal stem cells modulate microglial activation in the peri-infarct area in rats during the acute phase of stroke

AimBone marrow-mesenchymal stem cells (BM-MSCs) possess immunomodulatory properties in the brain. However, it remains unclear whether intravenously transplanted BM-MSCs have a neuromodulator effect on the activation of microglias after ischemic stroke. This study aimed to investigate the immunomodulatory effect of BM-MSCs on the regulation of brain microglial inactivation during the acute phase of stroke. MethodsA rat model of middle cerebral artery occlusion (MCAO) was established. Rat BM-MSCs were transplanted through the tail vein at 12 h after MCAO. CD200 Receptor 1 (CD200R1) antibody was injected into the peri-infarct area of the rat brain at 3 h prior to BM- MSCs transplantation. Protein expression was determined by immunofluorescence staining and Western blot. The volume of the infarct area was determined by TTC (2,3,5-triphenyltetrazolium hydrochloride) staining. Neuron apoptosis was determined by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. ResultsIn vitro study showed that co-culture with BM-MSCs significantly decreased LPS-induced iNOS expression in the microglial cells. Immunofluorescence and Western blot consistently revealed that BM-MSC transplantation significantly reduced the IBA-expressing microglial cells and IBA protein levels in the peri-infarct area. The inhibitory effect of BM-MSC on IBA expression was significantly attenuated by pretreatment of CD200R1 neutralizing antibody in the peri-infarct zone. BM-MSC transplantation significantly reduced the infarct volume, protected neuron apoptosis, and increased neuronal CD200 expression in the peri-infarct area. ConclusionThe transplanted BM-MSCs exerted immunomodulatory effect by inactivating the microglias in the peri-infarct area, at least partially, via the CD200-CD200R1 signaling.

Induced pluripotent stem cell-derived mesenchymal stem cells prolong hind limb survival in a rat vascularized composite allotransplantation model.

The reduction of systemic immunosuppressive agents is essential for the expansion of vascularized composite allotransplantation (VCA) in a clinical setting. The purpose of this study is to compare human-induced pluripotent stem cell-derived mesenchymal stem cells (iMSCs) with four other types of mesenchymal stem cells (human bone marrow-derived MSCs [BMMSCs], human adipose-derived MSCs [ADMSCs], rat BMMSCs, and rat ADMSCs) in vitro, and to investigate the in vivo immunomodulatory effect of iMSCs in a rat VCA model. One Brown Norway (BN) rat, 2 Lewis (LEW) rats, and 1 Wistar rat were used in the mixed lymphocyte reaction (MLR), and 9 BN rats and 3 LEW rats (for donors), and 24 LEW rats (for recipients) were used in the VCA model. The abovementioned five types of MSCs were imaged to examine their morphology and were also tested for suppressor function using a MLR. The 24 recipient LEW rats were divided randomly into four groups, and subjected to orthotopic hind limb transplantation. The three control groups were the Iso group, in which transplantation was performed on from three to six LEW rats without immunosuppressive treatment (n = 6); the FK group, in which transplantation was performed from BN rats to LEW rats and recipient rats were treated with tacrolimus alone (FK 506, 0.2 mg/kg, days 0-6 postoperatively, intraperitoneally) (n = 6); and the UT group, in which transplantation was performed from BN rats to LEW rats without any immunosuppressive treatment (n = 6). The experimental group was the iMSC group, in which transplantation was performed from BN rats to LEW rats and recipient rats were treated with tacrolimus (FK 506, 0.2 mg/kg, days 0-6 postoperatively, intraperitoneally) and injected with iMSCs (2 × 106 cells, day 7, intravenously) (n = 6). Hind limb survival was assessed by daily inspection of gross appearance until 50 days postoperatively. Histology of the skin and muscle biopsy were investigated on day 14 postoperatively. A time series of the plasma cytokine level (before transplantation, and at 10, 14, and 17 days after transplantation) was also analyzed. The size of adherent and trypsinized iMSCs was 67.5 ± 8.7 and 9.5 ± 1.1 μm, respectively, which was the smallest among the five types of MSCs (p < .01). The absorbance in MLR was significantly smaller with rat ADMSCs (p = .0001), human iMSCs (p = .0006), rat BMMSCs (p = .0014), human ADMSCs (p = .0039), and human BMMSCs (p = .1191) compared to without MSCs. In vivo, iMSC treatment prolonged hind limb survival up to 12.7 days in macroscopic appearance, which is significantly longer than that of the FK group (p < .01). Histology of the skin and muscle biopsy revealed that mononuclear cell infiltration was significantly reduced by iMSC injection (p < .01). iMSC treatment also affected proinflammatory cytokines (interferon-gamma (IFNγ) and tumor necrosis factor α (TNFα)) and the anti-inflammatory cytokine (interleukin-10 (IL-10)) of the recipient plasma. The IFNγ levels at Δ14 and the TNFα levels at Δ14 and Δ17 of the iMSC group were significantly lower than those of the FK group (p = .0226, .0004, and .004, respectively). The IL-10 levels at Δ10 and Δ14 of the iMSC group were significantly higher than those of the FK group (p = .0013 and .0374, respectively). iMSCs induce T cell hyporesponsiveness to prolong hind limb survival in a rat VCA model. This immunomodulatory property against acute rejection could provide one of the promising strategies capable of enabling the toxicities of immunosuppressants to be avoided in clinical settings.

The Role of MiR-339 in the Teriparatide-Induced Proliferation and Differentiation of Bone Marrow Mesenchymal Stem Cells

Osteoporosis is closely related to BMMSCs differentiation. Teriparatide promotes BMMSCs proliferation and differentiation with unclear mechanism. Both miR-339 and DLX5 are closely related to the differentiation of BMMSCs. Our study intends to assess the mechanism by how teripeptide promotes the proliferation and differentiation of BMMSCs. Rat BMMSCs were cultured and transfected with miR-339 inhibitor/NC and then treated with tripeptide (0, 10, 20, 50 nmol/L) followed by analysis of cell proliferation by CCK8 assay, alkaline phosphatase (ALP) activity, expression of miR-339, DLX5, Runx2 and OCN by real-time PCR, and DLX5 protein level by Western blot. miR-339 inhibitor transfection significantly decreased miR-339 expression, increased DLX-5 protein level, cell number, ALP activity and expression of osteogenic genes. Compared with 0 nmol/L group, 10, 20, 50 nmol/L group presented significantly increased cell number. With increased teriparatide concentration, cell number, ALP activity and expression levels of Runx2 and OCN was increased gradually and miR-339 and DLX5 expression was reduced. The luciferase activity in miR339 inhibitor and pmirGLO-DLX5-3′ UTR-wt-transfected cells was higher than cells transfected with miR-339 NC and pmirGLO-DLX5-3′ UTR-wt. Teriparatide promotes BMMSCs osteogenic differentiation by down-regulating miR-339 which targets DLX5 expression.

Effects of silencing the HIF-1α gene on the expression of BSP and osterix in rat BMMSCs under tension

Effects of silencing the HIF-1α gene on the expression of BSP and osterix in rat BMMSCs under tension

Tracking iron oxide labelled mesenchymal stem cells(MSCs) using magnetic resonance imaging (MRI) in a rat model of hepatic cirrhosis.

Homing and tumor attenuation potential of BM-MSCs labelled with superparamagnetic iron-oxide nanoparticles (SPIONs) in a rat model of hepatic cirrhosis was evaluated. Rat BM-MSCs were derived, characterized and labelled with SPIONs (200 nm; 25 mg Fe/ml). Hepatic cirrhosis was induced in Wistar rats (n=30; 10/group) with carbon tetrachloride (CCl4; 0.3 mL/kg body weight) injected twice a week for 12 weeks. Group-I was administered vehicle (castor-oil) alone; Group-II received two doses of unlabelled BM-MSCs (3x106 cells) and Group-III received two doses of SPIONs labelled BM-MSCs (3x106 cells) via tail vein injection (0.5 ml) at weekly intervals. All animals were sacrificed after two weeks for histological, radiological and biochemical analysis. Derived BM-MSCs demonstrated MSCs related CD markers. Histology confirmed induction of hepatic cirrhosis with CCL4. Levels of alanine-aminotransferase, aspartate-aminotransferase,alkaline-phosphatase and gamma glutamyl-transferase returned to normal levels following treatment with BM-MSCs. Uptake and homing of SPIONs labelled BM-MSCs, and reduction in the size of cirrhotic nodules were confirmed using transmission electron microscopy and magnetic resonance imaging respectively. BM-MSCs reduced the pathological effects of CCL4 induced hepatic cirrhosis and labelling BMMSCs with SPIONs were non-toxic and enabled efficient tracking using non-invasive methods.

Comparison of the effect of crocin and crocetin, two major compounds extracted from saffron, on osteogenic differentiation of mesenchymal stem cells

BackgroundMesenchymal stem cells (MSCs) can be considered as an effective tool for bone regeneration. It is variable to find new agents with low cytotoxicity and high efficiency for induction of MSCs into osteoblasts. In the present study, the ability of crocin and crocetin, extracted from saffron, to induce cell differentiation of rat bone marrow-derived mesenchymal stem cells (rat BM-MSCs) into osteoblasts was compared. MethodsBone marrow cells were isolated from rat's femurs and tibias. Cytotoxic effect of crocin and crocetin was assayed using MTT test and IC50 was calculated from the results. Osteogenic ability of crocin and crocetin at non-toxic concentrations has been evaluated and compared to osteogenic standard medium after 7 and 21 days, using alizarin red (ALZ) staining and alkaline phosphatase (ALP) activity. Furthermore, ALP mRNA expression has been analyzed by real time RT-PCR. ResultsCrocetin showed more cytotoxic effect on stem cells compared to crocin. Non-toxic concentrations (12.5, 25 and 50 μM) were selected for other experiments. Crocin and crocetin (25 μM) increased ALZ intensity (4.2 ± 0.12 and 3.8 ± 0.16 folds, respectively), ALP activity (46.4 ± 5.8 and 43.2 ± 1.9 folds, respectively) and ALP mRNA expression (14.27 ± 1.98 and 8.4 ± 1.17 folds, respectively) in MSCs after day 21 compared to negative control. Although, crocin was more effective than crocetin, but this difference was not significant. ConclusionAccording to these findings, crocin and crocetin could effectively enhance osteogenic differentiation of MSCs and can be considered as safe therapeutic agents in clinical applications.

In vitro reprogramming of rat bmMSCs into pancreatic endocrine-like cells.

Islet transplantation provides curative treatments to patients with type 1 diabetes, but donor shortage restricts the broad use of this therapy. Thus, generation of alternative transplantable cell sources is intensively investigated worldwide. We previously showed that bone marrow-derived mesenchymal stem cells (bmMSCs) can be reprogrammed to pancreatic-like cells through simultaneously forced suppression of Rest/Nrsf (repressor element-1 silencing transcription factor/neuronal restrictive silencing factor) and Shh (sonic hedgehog) and activation of Pdx1 (pancreas and duodenal transcription factor 1). We here aimed to reprogram bmMSCs further along the developmental pathway towards the islet lineages by improving our previous strategy and by overexpression of Ngn3 (neurogenin 3) and NeuroD1 (neurogenic differentiation 1), critical regulators of the development of endocrine pancreas. We showed that compared to the previous protocol, the overexpression of only Pdx1 and Ngn3 reprogrammed bmMSCs into cells with more characteristics of islet endocrine lineages verified with bioinformatic analyses of our RNA-Seq datasets. These analyses indicated 2325 differentially expressed genes including those involved in the pancreas and islet development. We validated with qRT-PCR analysis selective genes identified from the RNA-Seq datasets. Thus, we reprogrammed bmMSCs into islet endocrine-like cells and advanced the endeavor to generate surrogate functional insulin-secreting cells.

Participation of TNF-α in Inhibitory Effects of Adipocytes on Osteoblast Differentiation.

Mesenchymal stem cells from bone marrow (BM-MSCs) and adipose tissue (AT-MSCs) are attractive tools for cell-based therapies to repair bone tissue. In this study, we investigated the osteogenic and adipogenic potential of BM-MSCs and AT-MSCs as well as the effect of crosstalk between osteoblasts and adipocytes on cell phenotype expression. Rat BM-MSCs and AT-MSCs were cultured either in growth, osteogenic, or adipogenic medium to evaluate osteoblast and adipocyte differentiation. Additionally, osteoblasts and adipocytes were indirectly co-cultured to investigate the effect of adipocytes on osteoblast differentiation and vice versa. BM-MSCs and AT-MSCs exhibit osteogenic and adipogenic potential under non-differentiation-inducing conditions. When exposed to osteogenic medium, BM-MSCs exhibited higher expression of bone markers compared with AT-MSCs. Conversely, under adipogenic conditions, AT-MSCs displayed higher expression of adipose tissue markers compared with BM-MSCs. The presence of adipocytes as indirect co-culture repressed the expression of the osteoblast phenotype, whereas osteoblasts did not exert remarkable effect on adipocytes. The inhibitory effect of adipocytes on osteoblasts was due to the release of tumor necrosis factor alpha (TNF-α) in culture medium by adipocytes. Indeed, the addition of exogenous TNF-α in culture medium repressed the differentiation of BM-MSCs into osteoblasts mimicking the indirect co-culture effect. In conclusion, our study showed that BM-MSCs are more osteogenic while AT-MSCs are more adipogenic. Additionally, we demonstrated the key role of TNF-α secreted by adipocytes on the inhibition of osteoblast differentiation. Thus, we postulate that the higher osteogenic potential of BM-MSCs makes them the first choice for inducing bone repair in cell-based therapies.

Induced Monocytes-Derived HSCs (CD34+) with LPS Accelerated Homing Rat Bone Marrow-Mesenchymal Stem Cell (BM-MSCs, CD105) in Injured Pancreas

Investigating the function of combining induced rat monocytes-derived bone marrow-haemopoietic stem cell (rat BM-HSCs) with LPS and rat bone marrow-mesenchymal stem cell (rat BM-MSCs) was to analyze the acceleration of homing process mechanism in injured pancreas. Mononucleated stem cells were isolated from aspirated whole rat BM using ficoll and cultured in α-MEM complete growth medium in 10 cm petridish. After two days, adherent cells after washing twice in petridish were added α-MEM growth medium and then mesenchymal cells were characterized using CD105 marker in third passage and labeled PKH26. Then haemopoietic stem cells (HSCs) were isolated with magnetic beads CD34+ and differentiated in vitro, and then induced monocytes with LPS. Animal experiment used 28 male Wistar rats, and divided them into 4 groups. After transplantation combined, both cells between monocyte derived HSc (mHSCs) and rat BM-MSC were analyzed expression of pair box gen 4 (Pax4), pancreatic and duodenal homeobox (Pdx1), C-peptide using immunohistochemistry, then secretion of insulin and C-peptide analyzed using indirect ELISA. Results showed that the expressions of Pax4, Pdx1, C-peptide found in the surface membrane cell of pancreatic cell, and secreted C-peptide and insulin were shown significant (P < 0.05) in transplanted group 2, 3 and 4, but in group 3 were transplanted with combined cells more dominant than non-combined cells. Conclusions suggested that combining of induced monocytes-derived HSCs and rat BM-MSCs has accelerated homing MSCs into injured pancreatic tissue.

Multimodal Approaches for Regenerative Stroke Therapies: Combination of Granulocyte Colony-Stimulating Factor with Bone Marrow Mesenchymal Stem Cells is Not Superior to G-CSF Alone.

Attractive therapeutic strategies to enhance post-stroke recovery of aged brains include methods of cellular therapy that can enhance the endogenous restorative mechanisms of the injured brain. Since stroke afflicts mostly the elderly, it is highly desirable to test the efficacy of cell therapy in the microenvironment of aged brains that is generally refractory to regeneration. In particular, stem cells from the bone marrow allow an autologous transplantation approach that can be translated in the near future to the clinical practice. Such a bone marrow-derived therapy includes the grafting of stem cells as well as the delayed induction of endogenous stem cell mobilization and homing by the stem cell mobilizer granulocyte colony-stimulating factor (G-CSF). We tested the hypothesis that grafting of bone marrow-derived pre-differentiated mesenchymal cells (BM-MSCs) in G-CSF-treated animals improves the long-term functional outcome in aged rodents. To this end, G-CSF alone (50 μg/kg) or in combination with a single dose (106 cells) of rat BM MSCs was administered intravenously to Sprague-Dawley rats at 6 h after transient occlusion (90 min) of the middle cerebral artery. Infarct volume was measured by magnetic resonance imaging at 3 and 48 days post-stroke and additionally by immunhistochemistry at day 56. Functional recovery was tested during the entire post-stroke survival period of 56 days. Daily treatment for post-stroke aged rats with G-CSF led to a robust and consistent improvement of neurological function after 28 days. The combination therapy also led to robust angiogenesis in the formerly infarct core and beyond in the “islet of regeneration.” However, G-CSF + BM MSCs may not impact at all on the spatial reference-memory task or infarct volume and therefore did not further improve the post-stroke recovery. We suggest that in a real clinical practice involving older post-stroke patients, successful regenerative therapies would have to be carried out for a much longer time.

Transplantation of human bone marrow mesenchymal stem cells as a thin subretinal layer ameliorates retinal degeneration in a rat model of retinal dystrophy

Vision incapacitation and blindness associated with retinal degeneration affect millions of people worldwide. Cell based therapy and specifically transplantation of human adult bone marrow-derived stem cells (hBM-MSCs) present possible treatment strategy. Subretinal transplantation of human or rat BM-MSCs was shown previously to improve retinal function in Royal College Surgeons (RCS) rats. In those studies cells were transplanted via a transscleral-transchoroidal approach, creating a localized subretinal bleb. Limited number of cells could be injected and photoreceptor rescue was restricted to areas in proximity to the injection site. Here we describe a new surgical method for subretinal transplantation that facilitates uniform distribution of transplanted cells as a thin layer along most of the subretinal space. We assessed the therapeutic effect of hBM-MSCs on RCS rats when transplanted either subretinally or intravitreally. We also examined whether a second transplantation can prolong the therapeutic effect. A cell suspension of 2.5 × 106 cells in 5 μl was injected subretinally or intravitreally in RCS rats at 28 days postnatal. In the subretinal group, hBM-MSCs were transplanted posterior to the limbus in the superotemporal part of the eye through a longitudinal triangular scleral tunnel reaching the choroid. In the intravitreal group, the cells were injected into the superotemporal part of the vitreous cavity. In cross sections of subretinally transplanted eyes, removed 2 h following transplantation, hBM-MSCs were distributed as a near-homogenous thin layer along most of the subretinal space. In some animals the cells were also detected in the choroid. In the intravitreal injection group, hBM-MSCs were clustered in the vitreous cavity. Transplanted cells could be detected up to 2 weeks after transplantation but not at later time points. Retinal function and structure were assessed by electroretinogram (ERG) and histology analysis, respectively. Six weeks post transplantation, the mean maximal scotopic ERG b-wave amplitude response recorded in RCS control eyes was 1.2 μV. By contrast, in transplanted eyes mean responses of 56.4 μV and 66.2 μV were recorded in the intravitreally and subretinally transplanted eyes, respectively. In the subretinal group, retinal function was significantly higher in transplanted compared with control eyes up to 20 weeks following transplantation. By contrast, in the intravitreal group, rescue of retinal function persisted only up to 12 weeks following transplantation. Histological analysis revealed that 8 weeks following subretinal transplantation, the retinas of control eyes were dystrophic, with outer nuclear layer (ONL) containing a single cell layer. An extensive photoreceptor rescue was demonstrated in transplanted eyes at this time point, with 3–4 cell layers in the ONL along the entire retina. A second subretinal transplantation at 70 days postnatal did not enhance or prolong the therapeutic effect of hBM-MSCs. No immunosuppressants were used and long-term safety analysis demonstrated no gross or microscopic adverse effects. Taken together our findings suggest that transplantation of hBM-MSCs as a thin subretinal layer enhances the therapeutic effect and the safety of cell transplantation.

In vitro Assay of Human Gingival Scaffold in Differentiation of Rat's Bone Marrow Mesenchymal Stem Cells to Keratinocystes.

Tissue engineering is an attractive science because it promises new therapeutic strategies for repairing organs that have lost functions due to damage. The purpose of this study was to evaluate induction effect of human gingival scaffold in tissue engineering for skin regeneration. Tissue samples were obtained from crown-lengthening procedures and wisdom teeth removal. The samples were decellularized and used as a scaffold for loading of rat BM-MSCs. The human gingival scaffolds loaded by bone marrow mesenchymal stem cells were derived from Wistar rat. Finally, it was evaluated via electron micrographs, as well as immunohistochemical techniques at day 7, 14, and 28 after initial seeding. The histologic sections of human gingival scaffold -loaded rat BM-MSCs demonstrated formation of epithelial like layers at days 7, 14 and 28 after initial seeding. Scanning electron microscope (SEM) of the scaffolds indicated formed desmosomal adhesions, which revealed a degree of differentiation toward keratinocytes. The results of immunohistochemical staining were strongly positive for multi cytokeratin (CK) 14 days after initial seeding in epithelial differentiation. Rat BM-MSCs which loaded on human gingival scaffold is capable of differentiating toward keratinocytes. Gingival tissues were presented as a natural scaffold for attachment and differentiation of bone marrow mesenchymal stem cells towards keratinocytes, and might be used as suitable scaffold for reconstruction of the skin.

In vitro reprogramming of rat bone marrow-derived mesenchymal stem cells into insulin-producing cells by genetically manipulating negative and positive regulators

Islet cell replacement therapy represents the most promising approach for the cure of type 1 diabetes if autoimmunity to β cells is under control. However, this potential is limited by a shortage of pancreas donors. To address the donor shortage problem, we determined whether bone marrow-derived mesenchymal stem cells (bmMSCs) can be directly reprogrammed to islet lineages by simultaneously forced suppression and over-expression of key regulator genes that play critical roles during pancreas development. Here, we report that rat bmMSCs were converted in vitro into insulin-producing cells by suppressing two-repressor genes repressor element-1 silencing transcription factor/neuronal restrictive silencing factor (Rest/Nrsf) and sonic hedgehog (Shh) and by over-expressing pancreas and duodenal transcription factor 1 (Pdx1). The reprogrammed bmMSCs expressed both genes and proteins specific for islet cells. These converted cells were capable of releasing insulin in a glucose-responsive manner. Our study suggests that bmMSCs may ultimately be reprogrammed to functional insulin-secreting cells.

Bone Marrow-Derived Mesenchymal Stromal Cells Enhance Chimeric Vessel Development Driven by Endothelial Cell-Coated Microtissues

Adding bone marrow-derived mesenchymal stromal cells (bmMSCs) to endothelialized collagen gel modules resulted in mature vessel formation, presumably caused in part by the observed display of pericyte-like behavior for the transplanted GFP(+) bmMSCs. A previous study determined that rat aortic endothelial cells (RAECs) delivered on the surface of small (∼0.8 mm long×0.5 mm diameter) collagen gel cylinders (microtissues, modular tissue engineering) formed vessels after transplantation into immunosuppressed Sprague-Dawley (SD) rats. Although the RAECs formed vessels in this allogeneic transplant model, there was a robust inflammatory response and the vessels that formed were leaky as shown by microcomputed tomography (microCT) perfusion studies. In vitro assays showed that SD rat bmMSCs embedded into the collagen gel modules increased the extent of EC proliferation and enhanced EC sprouting. In vivo, although vessel number was not affected, the new vessels formed by the bmMSCs and RAECs were more stable and leaked less in the microCT perfusion analysis than vessels formed by implanted RAECs alone. Addition of the bmMSCs also decreased the total number of CD68(+) macrophages that infiltrated the implant and changed the distribution of CD163(+) (M2) macrophages so that they were found within the newly developed vascularized tissue. Most interestingly, the bmMSCs became smooth muscle actin positive and migrated to surround the EC layer of the vessel, which is the location typical of pericytes. The combination of these two effects was presumed to be the cause of improved vascularity when bmMSCs were embedded in the EC-coated modules. Further exploration of these observations is warranted to exploit modular tissue engineering as a means of forming large vascularized functional tissues using microtissue components.

Neural Markers Espression in Rat Bone Marrow Mesenchymal Stem Cell Cultures Treated with Neurosteroids

The aim of the present investigation is to study the effects of DEX or E(2) treatment during differentiation towards neural cell line of rat BM-MSCs in culture. In order to better characterize biochemically our in vitro model, we evaluate by western blotting and immunocytochemical analysis some neural lineage markers (nestin, neurofilament, β-tubulin) and MAP-Kinases. An enhanced expression of the neural markers and MAP-Kinase in DEX-treated BM-MSCs cultures is found. In addition, E(2)-treatment increases MAP-Kinase and β-tubulin expression, but it decreases nestin and neurofilament expression. In conclusion, our findings highlight a significant up and down modulation of nestin, neurofilament, β-tubulin and MAP-Kinases expression in neurosteroids-treated BM-MSCs. In particular, our results clarify the molecular mechanism involved during eventual differentiation of these stem cells treated with DEX and E(2), addressed towards a neural cell line, that may express neurotrophic receptors and release neurotrophines particularly implicated during neurogenesis processes.

Epidermal Growth Factor as a Candidate for Ex Vivo Expansion of Bone Marrow–Derived Mesenchymal Stem Cells

Bone marrow mesenchymal stem cells (BMMSCs) are pluripotent cells capable of differentiating into several cell types and are thus an attractive cell source for connective tissue engineering. A challenge in such a use is expansion and directed seeding in vitro, requiring proliferation and survival, and directed migration, respectively, prior to functional differentiation. The epidermal growth factor (EGF) receptor (EGFR) is the prototypal growth factor receptor and elicits these responses from a wide variety of stromal, epithelial, and endothelial cells. Ligands for this receptor are appealing for use in tissue engineering because they are relatively resistant to biological extremes and amenable to high-volume production. Therefore, we determined whether an EGFR ligand, EGF, could be used for ex vivo expansion of BMMSCs. EGF stimulated motility in rat and immortalized human BMMSCs. EGF-induced proliferation was observed in immortalized human BMMSCs but was not apparent in rat BMMSCs under our experimental conditions. EGF did not, however, rescue either type of BMMSC from apoptosis due to lack of serum. During our examination of key signaling intermediaries, EGF caused robust phosphorylation of extracellular signal-regulated protein kinase (ERK) and protein kinase B/akt (AKT) but only minimal phosphorylation of EGFR and phospholipase C-gamma in rat BMMSCs, whereas in the human BMMSCs these intermediaries were all strongly activated. EGF also induced robust ERK activation in primary porcine mesenchymal stem cells. EGF pretreatment or cotreatment did not interfere with secondarily induced differentiation of either type of BMMSC into adipogenic or osteogenic lineages. Platelet-derived growth factor (PDGF) effects were similar to but not additive with those elicited by EGF, with some quantitative differences; however, PDGF did interfere with the differentiation of these BMMSCs. These findings suggest that EGFR ligands could be used for ex vivo expansion and direction of BMMSCs.