Differentiation of mouse iPSCs into insulin-producing cells and experimental study on treating diabetes

AIM: To induce mouse induced pluripotent stem cells (iPSCs) to differentiate into insulin-producing cells (IPCs) by a new 3-step method, and to detect the efficiency and maturity for the treatment of diabetic mice. METHODS: We constructed iPSCs from mouse embryonic fibroblasts of male C57/C mouse by piggyBac transposon, then induced the iPSCs into IPCs by a 3-step method. The cell morphological change was traced by microscopy during the process of differentiation. The expression of mRNA and protein associated with islet β cell development was determined by real-time PCR and immunofluorescence staining. Flow cytometry was used to analysis the efficiency of differentiation. Insulin and C-peptide secretions of IPCs in response to glucose at high (25 mmol/L) or low (5.5 mmol/L) level were measured by ELISA. The IPCs were transplanted into the capsul of left kidney in the male C57/C diabetic mouse model. Blood glucose was continuously monitored for 28 day, serum insulin was tested by ELISA in different stages. The glucose tolerance test was performed on the 28th day, and the left kidney was excised. RESULTS: IPCs were obtained from mouse iPSCs by the 3-step method. The cells expressed the marker genes (Pdx1, Ngn3, Pax6 and Ins2) and proteins (Pdx1, Nkx6.1 and insulin) of β cells. The glucose stimulation induced the secretion of insulin and C-peptide. The efficiency of differentiation was 28% detected by flow cytometry. After transplantation of IPCs to the diabetic mice, the blood glucose was decreased to normal level on the 3rd day,and serum insulin level and the ability of regulating glucose were improved. IPCs were still alive after 28 d of transplantation by pathological observation. CONCLUSION: iPSCs is efficiently induced into IPCs by a 3-step method , and the induction time is shortened significantly. The hyperglycemia of diabetes mice is reversed after transplanting IPCs to same sex inbred strain mice.     

Effects of maxadilan on proliferation of human induced pluripotent stem cells

AIM: To investigate the promoting effect of maxadilan, which specifically activate the type I receptor for pituitary adenylate cyclase-activating polypeptide (PACAP), on the proliferation of human induced pluripotent stem cells (IPSCs). METHODS: PACAP type I (PAC1) receptor in IPSCs was detected by RT-PCR and Western blotting. maxadilan at various concentrations was added to the medium of IPSCs as experimental groups. The medium in control group was without maxadilan treatment. The effect of maxadilan on theproliferation of IPSCs was measured with Cell Counting Kit-8 (CCK-8). The changes of cell cycle caused by maxadilan in IPSCs were analyzed by flow cytometry. The analysis of karyotype was carried out in IPSCs treated with maxadilan. Proteins and gene expression levels of both Nanog and OCT4 in IPSCs treated with maxadilan were detected by real-time quantitative polymerase chain reaction (real-time-qPCR) and immunofluorescence. The gene expression levels of Nestin and PAX6 in both IPSCs treated with maxadilan and cells of embryonic body, which was birthed from IPSCs with maxadilan treatment, were detected by real-time qPCR. The ability of IPSCs treated with maxadilan differentiating into 3 embryonic layers was evaluated by analyzing the component of embryo using RT-PCR. RESULTS: The PAC1 receptor in IPSCs was identified by RT-PCR and Western blotting. Viability of the IPSCs with 100 nmol/L maxadilan treatment was increased by 16% compared with control group. The differences with statistical significance were found in the cell viability between 100 nmol/L maxadilan treatment group and control group (P<0.05). The average values of proliferation index (PI) in IPSCs with 100 nmol/L maxadilan treatment for 3 h, 6 h and 9 h were 47.23%, 59.70% and 55.67%,respectively, while that in control group was 37.00%. The differences with statistical significance were found in PI between 100 nmol/L maxadilan treatment for 3 h group, 6 h group, 9 h group and control group (P<0.05). Normal karyotype and unchanged pluripotent state in IPSCs treated with maxadilan were observed. Compared with control group, the gene expression levels of Nestin and PAX6 were not significantly different in both IPSCs and the cells of embryonic body birthed from IPSCs with maxadilan treatment. The ability of differentiation into 3 embryonic layers in IPSCs treated with 100 nmol/L maxadilan was found. CONCLUSION: PAC1 receptor presents in IPSCs. Maxadilan promotes the proliferation of IPSCs but does not affect their pluripotent state and karyotype.     

Research progress in reprogramming induced pluripotent stem cells

Induced pluripotent stem cells (iPSCs) have been first induced from mouse fibroblasts since 2006, and the research on iPSCs has made great progress in the following years. iPS cell lines were established from different somatic cells through DNA, RNA, protein, and small molecule compounds and various methods of transduction, making the induction of iPSCs more secure and effective, and more attractive prospect of clinical application. In this review, different somatic cell reprogramming, different levels of reprogramming, different transduction pathways, and prospect of application are discussed.     

Generation of thalassemia-specific integration-free induced pluripotent stem cells and determination of their differentiation ability

AIM: To generate thalassemia-specific integration-free induced pluripotent stem cells(iPSC) and to detect their ability of differentiation into hematopoietic precursors.METHODS: The plasmids pEB-C5 and pEB-Tg were transfected into the fibroblast cells from hemoglobin Bart's hydrops fetalis's skin by the method of nuclear transfection to reprogramm the cells into iPSC. The ability of the iPSC to differentiate into 3-germ layer cells was determined. The iPSC were cocultured with mouse OP9 cells to differentiate into hematopoietic precursors and the hematopoietic precursor specific antigens were detected. RESULTS: The integration-free iPSC from hemoglobin Bart's hydrops fetalis's skin fibroblasts were successfully derived, and had the ability to differentiate into 3 germ layers. When cocultured with OP9 cells for 9 d, the positive rate of hematopoietic progenitor cell marker CD34 was 18.7%, and the CD34 and CD45 double positive rate was 12.2%. CONCLUSION: Hemoglobin Bart's hydrops fetalis's skin fibroblasts can be successfully induced into "integration-free" iPSC. This cell line has the ability to differentiate into 3 germ layers, and can be differentiated into hematopoietic precursors when cocultured with OP9 cells.     

Generation of induced pluripotent stem cells and neural cells from urine-derived cells of Alzheimer disease patients

AIM: In this study, we aim to obtain the induced pluripotent stem cells (iPSCs) from the patients with sporadic Alzheimer disease (AD). METHODS: Three typical Alzheimer's patients were chosen, and the epithelial cells were isolated from their urine. We reprogrammed these cells into induced pluripotent stem cells by transfection of 4 factors (Oct4, Sox2, Klf4 and SV40LT) with the technique of electro-transfection. After getting these iPSCs, we continue to differentiate them into neural cells by a specific method—dual inhibition of Smad signaling. RESULTS: The primary cells from 3 AD patients were successfully reprogrammed to iPSCs, and these patients-derived iPSCs were differentiated into neural cells. There was no significant difference, during iPSCs reprogramming and neural differentiation, between cells from AD patients and normal people. CONCLUSION: The urine cells from AD patients were able to transfer to iPSCs, functional neurons and neurogliocytes.     

Differentiation of neurons from mouse induced pluripotent stem cells in vitro

AIM: To study the induction method of mouse induced pluripotent stem cells (iPSCs) that differentiate into neurons in vitro. METHODS: Mouse iPSCs were cultured in non-adherent culture dishes for 2 d to form embryoid bodies (EBs). The EBs were cultured for consecutive 2 d in the presence of retinoic acid (RA), and then were plated in the serum-free medium for adherent culture. Seven days later, Pasteur pipette was used to detach the differentiated cells around adherent EBs into “fragment” cell colonies with the help of dissecting microscopes, and these “fragments” were transferred to culture dishes with neural stem cell medium. Another 7 days later, the cells were plated onto the culture dishes using differentiation medium containing fetal bovine serum (FBS) and RA. The morphological changes of the cells were observed under inverted microscope. The iPSCs markers Oct4, Sox2 and SSEA1, the neural stem cell (NSC) marker nestin, the neuronal marker microtubule-associated protein 2 (MAP-2), the astrocyte marker glial fibrillary acidic protein (GFAP) and oligodendrocyte marker myelin basic protein (MBP) were detected by immunofluorescence method. The mRNA expression of GFAP, nestin, β3-tubulin, MAP-2 and MBP was detected by RT-RCR. MAP-2 gene sequence was identified. The proportions of NSCs differentiated from iPSCs and neurons from NSCs were detected by flow cytometry. RESULTS: Mouse iPSCs strongly expressed Oct4, Sox2 and SSEA1, and formed spherical EBs by suspended culture. The EBs were induced by RA and serum-free medium in adherent culture for 2 d, and rosette structure was observed under the microscope. “Fragments” separated by Pasteur pipette from the rosette structure formed neurosphere-like colonies. After the colonies were cultured in adherent condition for 5 d to 7 d in the presence of RA and FBS, the typical neurite was observed under the microscope. The neurospheres expressed nestin and their differentiated derivatives expressed MAP-2, GFAP and MBP, respectively. RT-PCR analysis and gene sequencing showed that the neurons were induced successfully. The results of flow cytometry demonstrated that 63.93%±1.47% of iPSCs differentiated into NSCs and 21.4%±1.70% of NSCs differentiated into neurons. CONCLUSION: Mouse iPSCs proliferate stably and differentiate into neurons in vitro, which provide a reliable source for the treatment of spinal cord injury.     

Effect of miR-375 on viability,cell cycle and apoptosis of colon cancer HCT116 cells

AIM: To investigate the effect of microRNA-375 (miR-375) on the viability, cell cycle and apoptosis of HCT116 cells.METHODS: The expression of miR-375 in different colorectal cancer cell lines was detected by real-time PCR. The miR-375 mimics was transfected into HCT116 cells by Lipofectamine^TM 2000. The mRNA expression of miR-375 and AEG-1 was detected by real-time PCR. The HCT116 cell viability was detected by MTT assay. The changes of apoptosis and cell cycle distribution were analyzed by flow cytometry.RESULTS: Real-time PCR showed that miR-375 expression was the lowest in HCT116 among 4 colorectal cancer cell lines. The expression level of miR-375 significantly increased in miR-375 mimics group compared with that in the negative control group. The high expression level of miR-375 significantly inhibited the mRNA expression of AEG-1. After transfection with miR-375 mimics, the cell viability was inhibited, the apoptotic rate was increased, the proportion of G₁-stage cells was increased, and the proportion of S-stage cells was decreased.CONCLUSION: miR-375 inhibits the viability, mediates the cell cycle arrest and promotes the apoptosis of colon cancer HCT116 cells. miR-375 may act as a tumor suppressor in colorectal cancer by inhibiting AEG-1.     

miR-708-5p accelerates migration of human mesenchymal stem cells by repressing TMEM88 expression

AIM: To investigate the effect of microRNA-708-5p(miR-708-5p) on the migration of human mesenchymal stem cells(hMSCs). METHODS: The expression of miR-708-5p was determined by miRNA arrays and real-time PCR. By transfection of miR-708-5p mimic or inhibitor, the up-regulation or down-regulation of miR-708-5p expression in hMSCs was evaluated. The cell scratch and Transwell tests were used to detect the migration capability of hMSCs. The effects of transmembrane protein 88(TMEM88), a miR-708-5p target gene, on β-catenin expression and migration of hMSCs were detected. RESULTS: The expression of miR-708-5p was down-regulated in the old hMSCs compared with the young hMSCs. Up-regulation of miR-708-5p resulted in increasing migration of hMSCs. Conversely, down-regulation of miR-708-5p resulted in decreasing cell migration. The expression of TMEM88 was up-regulated in the old hMSCs compared with the young hMSCs, while the expression of β-catenin was down-regulated. Directly repression of TMEM88 expression increased the β-catenin expression and migration of hMSCs. The regulation of miR-708-5p on hMSCs was attenuated by inhibiting the expression of miR-708-5p and TMEM88 together. CONCLUSION: miR-708-5p increases β-catenin expression and Wnt/β-catenin activity by repressing TMEM88, thus enhancing the migration of hMSCs.     

Supportive effects of human aorta-gonad-mesonephero stromal cells on the directed differentiation of embryonic stem cells into hematopoietic stem cells

AIM: To direct embryonic stem cells (ESCs) into hematopoietic stem cells (HSCs) in vitro by simulating the hematogenic microenvironment in human early embryonic aorta-gonad-mesonephero (AGM) region.METHODS: Murine E14 embronic stem cell line was used for two-step differentiation.In the first step of primary differentiation,E14 ESCs were seeded into semisolid methylcellulose-based medium containing bone morphogenesis protein 4 (BMP4) and vascular endothelial growth factor (VEGF) for embryoid body (EB) formation.On days 3,6,9,12 and 15,single EB cells were analyzed for Flk-1+ cells amount through flow cytometry.In the second step,single cell from EB containing most Flk-1+ cells was further co-cultured with human AGM stromal cells in non-contact system.On co-culture days of 3,6,9 and 12 days,cells were collected for cell count,flow cytometry for Sca-1+c-kit+ cells analysis,and colony forming cell assay.RESULTS: During the EB formation,BMP4+VEGF promoted Flk-1+ cell genesis on day 9 at peak pencentage value of 27.53%±2.84％,which was statistically higher than that in control group as 8.77±1.10 (P<0.05).Collagenase-disassociated single cell from day 9 EB was co-cultured with human AGM stromal cells of hAGMS3 or hAGMS4 for further hematopoietic differentiation.On day 6 Sca-1+c-kit+ cells got to peak value as 7.31%±1.21％ ［(2.57±0.48) folds］ and 7.62%±1.52％ ［(2.35±0.36) folds］ in hAGMS3 and hAGMS4 feeder systems,respectively,both of which were greater than those values of no-stroma groups at the same culture duration (P<0.05).Colonogenic cell assay showed that these Sca-1+c-kit+ cells had ability of forming multiple lineage hematopoietic colonies.CONCLUSION: BMP4 in combination with VEGF promotes Flk-1+ cell genesis during EB formation in vitro.Stromal cells from early human embryonic AGM region further enhance the directed differentiation of these primitive cells into HSCs.This two-step induction differentiation model can be used for molecular mechanism study of ESCs hematopoietic differentiation.     

MicroRNA-378*enhances apoptosis of human mesenchymal stem cells by repressing expression of CTGF

AIM: To investigate the effects of microRNA-378* (miR-378*) on the survival and apoptosis of human mesenchymal stem cells (hMSCs). METHODS: The expression of miR-378* was determined by microRNA arrays and quantitative real-time PCR (qRT-PCR). H2O2 was used to induce hMSCs apoptosis. By transfection of miR-378* mimic or inhibitor, we up-regulated or down-regulated miR-378* expression in hMSCs. The effect of miR-378* and connective tissue growth factor (CTGF) on hMSC survival and apoptosis were detected by MTT, LDH, caspase-3/7 and TUNEL assays. RESULTS:The expression of miR-378* was up-regulated in the old hMSCs compared with the young hMSCs. H2O2 increased the expression of miR-378*, decreased the expression of CTGF. Up-regulation of miR-378* resulted in increasing apoptosis and decreasing survival of hMSCs. Conversely, down-regulation of miR-378* resulted in decreasing cell apoptosis and increasing survival. The regulation of miR-378* on hMSC apoptosis and survival was attenuated by inhibiting the expression of miR-378* and CTGF together. Direct repression of CTGF expression inhibited the hMSC survival and increased apoptosis. CONCLUSION: miR-378* enhances apoptosis of hMSCs by repressing the expression of CTGF.     

Role of miR-486-5p in apoptosis of human bone marrow mesenchymal stem cells induced by hydrogen peroxide

AIM: To investigate the role of microRNA-486-5p (miR-486-5p) in the apoptosis of human bone marrow mesenchymal stem cells (hMSCs) induced by hydrogen peroxide (H₂O₂). METHODS: The hMSCs were cultured in vitro and exposed to serum-free medium and H₂O₂ (10 mmol/L). The changes of miR-486-5p expression in oxidative stress-related apoptosis of hMSCs were measured by real-time PCR. The hMSCs were transfected with miR-486-5p mimic or inhibitor at concentration of 30 nmol/L by Lipofectamine RNAiMAX. The effect of miR-486-5p on H₂O₂-induced decrease in cell viability was evaluated by MTT assay. Hoechst 33342 staining and flow cytometry were applied to determine the role of miR-486-5p in the apoptosis of hMSCs. The protein expression was evaluated by Western blotting. Caspase-3 activity was determined using a caspase-3 activity kit. RESULTS: Compared with control group, the expression of miR-486-5p significantly decreased after treated with H₂O₂ (P<0.05). In addition, over-expression of miR-486-5p in the hMSCs reduced the cell viability, accelerated apoptosis, down-regulated Bcl-2/Bax ratio, caspase-3 enzyme precursor content and phosphorylation of Akt, and activated caspase-3 activity. Conversely, down-regulation of miR-486-5p significantly inhibited H₂O₂-induced cell apoptosis and the caspase-3 activity, increased cell viability and up-regulated Bcl-2/Bax ratio and phosphorylation level of Akt. CONCLUSION: Over-expression of miR-486-5p promotes H₂O₂-induced hMSCs apoptosis, and repression of miR-486-5p protects hMSCs from H₂O₂-induced cellular apoptosis, which may be mediated by regulating Akt signaling pathway.     

Effect of lentiviral vector of microRNA-9-1 on differentiation of mouse bone marrow mesenchymal stem cells into neurons

AIM: To investigate the role of microRNA-9 in inducing bone marrow mesenchymal stem cell(MSCs) differentiation into neurons.METHODS: The lentiviral vector of microRNA-9-1(microRNA-9-1-LV) was constructed and transfected into mouse MSCs. The cells were divided into non-transfected group, transfected group(transfected with microRNA-9-1-LV) and negative control group(transfected with FU-RNAi-NC-LV). MSCs were treated with β-mercaptoethanol(β-ME) as an inducer for triggering the cells to differentiate into neurons. The fluorescence expressed by transfected MSCs were observed under inverted fluorescence microscope. The mRNA expression of microtublin-associated protein 2(MAP-2) was detected by RT-PCR. The expression of neuron-specific markers,neuron-specific enolase(NSE), MAP-2 and glial fibrillary acidic protein(GFAP), were measured by immunocytochemical method. The viability of MSCs was determined by MTT method. RESULTS: The results of PCR confirmed successful construction of mouse microRNA-9-1-LV. The virus titer was 1×10¹² TU/L(TU, transduction unit). The best transfection efficiency(up to 91.3%±4.2%) and survival rate appeared when multiply of infection(MOI)was 20 and on 4th day. β-ME induced MSCs to differentiate into neurons and the best efficiency of the induction was observed in transfected group. The expression levels of NSE and MAP-2 in transfected cells were higher than those in the cells of other group(P<0.05).CONCLUSION: MicroRNA-9-1-LV has high transfection efficiency in mouse MSCs. Higher differentiation rate from mouse MSCs to neurons is induced by β-ME after the cells are transfected with microRNA-9-1-LV.     

Roles of reactive oxygen species in pluripotent stem cell functions

Pluripotent stem cells are characterized by the properties of self-renewal and the ability to differentiate into multiple cell types. Reactive oxygen species (ROS) are highly reactive metabolites. High levels of ROS are toxic and involved in stem cell senescence and apoptosis. However, regulation of ROS has an important role in maintaining “stemness” and differentiation of the stem cells. The role of ROS in the stem cells varies among different stem cell types. NADPH oxidase is one of the major sources of ROS in stem cells. Excessive amounts of ROS are produced in various pathophysiological states such as atherosclerosis, heart failure, hypertension, diabetes, and aging. Induced pluripotent stem cells have the potential to be used in modeling of ROS-associated diseases.Understanding the molecular mechanisms how ROS regulate the functions of stem cells will greatly enhance their translational applications. In this review, we summarize the recent progress regarding the roles of ROS in regulating the functions of embryonic and induced pluripotent stem cells.     

Anti-apoptosis effect of liraglutide on islet via regulating microRNA-375

AIM: To observe the anti-apoptosis effect of liraglutide on the islet through microRNA-375 (miR-375) for providing additional pharmacodynamic evidence for its clinical application. METHODS: For in vitro study, C57BL/KsJ-db/m mice aged 8 weeks served as normal control group. A total of 40 male genetically diabetic C57BL/KsJ-db/db mice at the same age were randomly divided into diabetic control group （the db/db mice were injected subcutaneously with equivalent amount of saline) and liraglutide group (the db/db mice were injected subcutaneously with liraglutide at dose of 300 μg·kg^-1·d^-1). After 8 weeks of administration, body weight (BW) was measured and blood was collected for detection of fasting blood glucose (FBG), fasting blood insulin (FINS), triglyceride (TG), total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C). Before sacrifice, intraperitoneal glucose tolerance test (IPGTT) and insulin tolerance test (ITT) were conducted. The histopathological features in the islet tissue were examined with HE staining. The apoptosis in the islet tissue was detected by TUNEL staining. The protein levels of caspase-3, Bcl-2 and Bax were determined by Western blot. The level of miR-375 in the islet tissue was detected by qPCR. Forin vitro study, the MIN-6 cells were cultured and divided into control group (incubated with equivalent amount of solvent), miR-375 mimic group and miR-375 mimic+ liraglutide group. The cell viability was examined by MTT assay. The protein levels of caspase-3, Bcl-2 and Bax were detected by Western blot. RESULTS: In thein vitro study, compared with control group, the levels of BW, FBG, FINS, TC, TG and LDL-C were decreased significantly in liraglutide group. The islet apoptosis was reduced by the administration of liraglutide. The expression of Bcl-2 was up-regulated significantly, while the protein levels of caspase-3 and Bax were down-regulated significantly in liraglutide group. The level of miR-375 was decreased significantly. In the in vitro study, the cell viability was decreased in miR-375 mimic group and increased in miR-375 mimic+liraglutide group. Moreover, the expression of Bcl-2 was decreased and the protein levels of caspase-3 and Bax were increased with the incubation of miR-375 mimic, while the expression of Bcl-2 was increased and the protein levels of caspase-3 and Bax were decreased with the co-incubation of miR-375 mimic and liraglutide. CONCLUSION: Liraglutide attenuates islet apotosis, and the mechanism may be associated with its effects of reducing the elevated level of miR-375 in islet tissues.     

Comparison of 2 methods for inducing iPSC to differentiate into neural stem cells

AIM: To select an efficient way of promoting induced pluripotent stem cells (iPSC) to differentiate into neural stem cells (NSC) by comparing 2 methods. METHODS: The culture system in method A contained SB431542 (5 mmol/L) and drosomophorin (5 mmol/L) with 100% initial cell density, while that in method B contained SB431542 (5 mmol/L) and drosomophorin (1 mmol/L) with 30%~50% initial cell density. For comparison and identification of the 2 methods, the growth state was observed under microscope, and the expression of Pax6, nestin, Sox1 and Sox2 was quantitatively detected by real-time PCR and flow cytometry. The related protein expression and the ability of spontaneous differentiation were determined by immunofluorescence analysis. RESULTS: The cells derived from method A with 5 mmol/L of SB431542 and drosomophorin and 100% initial cell density achieved the higher expression of Pax6, nestin, Sox1 and Sox2. The growth state was better and the cells differentiated into neurons and astrocytes normally. CONCLUSION: The method A was superior to method B, and we recommend the method A with 5 mmol/L of SB431542 and drosomophorin and 100% initial cell density as the method for differentiating NSC.     

Effect of miR-34a expression on transplantation of adipose-derived stem cells for treatment of Achilles tendonitis

AIM: To elucidate the role of microRNA-34a (miR-34a) in transplantation of human adipose-derived stem cells (hADSCs) for treatment of Achilles tendonitis. METHODS: The viability of hADSCs transfected with miR-34a mimic and miR-34a inhibitor for 24 h, 48 h, 72 h and 96 h was measured by CCK-8 assay. A rat model of collagenase-induced Achilles tendonitis was established. The rats with Achilles tendonitis were divided into 5 groups:PBS group, hADSCs group, hADSCs+NC group, hADSCs+miR-34a group and hADSCs+anti-miR-34a group. The tendon tissues were isolated to detect stiffness, stress and maximum loading tension by biomechanical evaluation and to assess miR-34a expression level as well as the expression of collagen I, scleraxis (Scx) and tenascin C (TNC) at mRNA and protein levels by RT-qPCR and Western blot. RESULTS: miR-34a over-expression and knockdown suppressed and enhanced the viability of hADSCs in a time-dependent manner, respectively. Moreover, stiffness, stress and maximum loading tension in hADSCs group were increased compared with PBS group, while these biomechanical indexes in hADSCs+miR-34a group and hADSCs+anti-miR-34a group were improved and reduced as compared with hADSCs+NC group, respectively. Furthermore, up-regulation of collagen I, Scx and TNC expression at mRNA and protein levels was observed in hADSCs group as compared with PBS group. Meanwhile, miR-34a expression was increased but the expression of collagen I, Scx and TNC at mRNA and protein levels declined in hADSCs+miR-34a group. In contrast, reversed effects on the trends mentioned above were observed in hADSCs+anti-miR-34a group.CONCLUSION: miR-34a affects therapeutic outcome for Achilles tendonitis by regulating the viability and differentiation of hADSCs.     

Effect of miR-21 over-expression on proliferation,migration and diffe-rentiation of c-Kit+ cardiac stem cells

AIM: To explore the effect of microRNA (miR)-21 on proliferation, migration and differentiation abilities of c-Kit⁺ cardiac stem cells (CSCs). METHODS: c-Kit⁺ CSCs were cultured and selected by the methods of enzyme digestion and magnetic bead separation. miR-21 mimics (50 nmol/L) and mimics negative control (MNC) were transfected into c-Kit⁺ CSCs with Lipofectamine^® 2000. The cells was divided into 3 groups:control group:c-Kit⁺ CSCs without any pretreatment; MNC group:the cells were transfected with MNC for 48 h; mimics group:the cells were transfected with miR-21 mimics for 48 h. qPCR was used to assess the expression of miR-21 in each group. CCK-8 and EdU assays were used to determine the cell proliferation. qPCR and immunofluorescence were used to detect the differentiation in each group. Scratch assay was adopted to explore the migration ability of the cells. RESULTS: The expression of c-Kit in the c-Kit⁺ CSCs were 90.8%, with 0.6% of CD45 and 0.5% of CD34. A significant increase in miR-21 expression was observed when the cells were transfected with miR-21 mimics for 48 h (P<0.05). CCK-8 and EdU assays showed that miR-21 significantly increased cell proliferation as compared with MNC group and control group (P<0.05). No difference in the expression of Nkx2.5, CD31 and α-SMA at mRNA and protein levels was observed, and no difference of the migration ability in 3 groups of the c-Kit⁺ CSCs was found. CONCLUSION: Over-expression of miR-21 significantly promotes the proliferation of c-Kit⁺ CSCs, without any effect on the cell migration and differentiation.