MicroRNA-22-3p Regulates the Expression of Kruppel-like Factor 6 to Affect the Cardiomyocyte-like Differentiation of Bone Marrow Mesenchymal Stem Cell / 中国医学科学院学报

Objective To explore the effect of microRNA-22-3p (miR-22-3p) regulating the expression of Kruppel-like factor 6 (KLF6) on the cardiomyocyte-like differentiation of bone marrow mesenchymal stem cell (BMSC). Methods Rat BMSC was isolated and cultured,and the third-generation BMSC was divided into a control group,a 5-azacytidine(5-AZA)group,a mimics-NC group,a miR-22-3p mimics group,a miR-22-3p mimics+pcDNA group,and a miR-22-3p mimics+pcDNA-KLF6 group.Real-time fluorescent quantitative PCR (qRT-PCR) was carried out to determine the expression of miR-22-3p and KLF6 in cells.Immunofluorescence staining was employed to detect the expression of Desmin,cardiac troponin T (cTnT),and connexin 43 (Cx43).Western blotting was employed to determine the protein levels of cTnT,Cx43,Desmin,and KLF6,and flow cytometry to detect the apoptosis of BMSC.The targeting relationship between miR-22-3p and KLF6 was analyzed by dual luciferase reporter gene assay. Results Compared with the control group,5-AZA up-regulated the expression of miR-22-3p (q=7.971,P<0.001),Desmin (q=7.876,P<0.001),cTnT (q=10.272,P<0.001),and Cx43 (q=6.256,P<0.001),increased the apoptosis rate of BMSC (q=12.708,P<0.001),and down-regulated the mRNA (q=20.850,P<0.001) and protein (q=11.080,P<0.001) levels of KLF6.Compared with the 5-AZA group and the mimics-NC group,miR-22-3p mimics up-regulated the expression of miR-22-3p (q=3.591,P<0.001;q=11.650,P<0.001),Desmin (q=5.975,P<0.001;q=13.579,P<0.001),cTnT (q=7.133,P<0.001;q=17.548,P<0.001),and Cx43 (q=4.571,P=0.037;q=11.068,P<0.001),and down-regulated the mRNA (q=7.384,P<0.001;q=28.234,P<0.001) and protein (q=4.594,P=0.036;q=15.945,P<0.001) levels of KLF6.The apoptosis rate of miR-22-3p mimics group was lower than that of 5-AZA group (q=8.216,P<0.001).Compared with the miR-22-3p mimics+pcDNA group,miR-22-3p mimics+pcDNA-KLF6 up-regulated the mRNA(q=23.891,P<0.001) and protein(q=13.378,P<0.001)levels of KLF6,down-regulated the expression of Desmin (q=9.505,P<0.001),cTnT (q=10.985,P<0.001),and Cx43 (q=8.301,P<0.001),and increased the apoptosis rate (q=4.713,P=0.029).The dual luciferase reporter gene experiment demonstrated that KLF6 was a potential target gene of miR-22-3p. Conclusion MiR-22-3p promotes cardiomyocyte-like differentiation of BMSC by inhibiting the expression of KLF6.

Effect of miR-203/CREB1 Signaling Regulation Mediated by DNA Methylation on the Proliferation and Apoptosis of Multiple Myeloma Cells / 中国实验血液学杂志

OBJECTIVE@#To investigate the effect of miR-203/CREB1 signaling regulation mediated by DNA methylation on the proliferation, invasion and apoptosis of multiple myeloma (MM) cells.@*METHODS@#The methylation level of miR-203 in the RPMI 8226 cells was detected by bisulfite sequcucing polymerase chain reaction (BSP). The mRNA expression of miR-203 was measured by quantitative real-time polymerase chain reaction. RPMI 8226 cells were treated with DNA methyltransferase inhibitor 5-Aza-2'-deoxycytidine (5-Aza-CdR). The miR-203 mimic in MM cell line RPMI 8226 was transfected to establish overexpressed miR-203 cell. The proliferation, invasion ability and apoptosis of RPMI 8226 cell was detected by CCK-8 assay, Transwell, and flow cytometry, respectively. The targeting relationship between miR-203 and CREB1 was verified by double luciferase report assay. Western blot was used to detect the expression of CREB1 protein.@*RESULTS@#Hypermethylation of miR-203 promoter region and low expression level of miR-203 mRNA were detected in the RPMI 8226 cells, which showed that demethylation could induce the expression of miR-203. The proliferation and invasion ability of RPMI 8226 cells after treated by 5-Aza-CdR were inhibited, and showed statistical significance as compared with blank control group (both P<0.05)，while the apoptosis rate was promoted (P<0.05). The proliferation, invasion ability and apoptosis of overexpressed miR-203 were the same as the demethylation group. Double luciferase report assay confirmed that CREB1 was the direct target of miR-203. The protein level of CREB1 was inhibited by demethylation and showed statistical significance as compared with control group (P<0.05).@*CONCLUSION@#MiR-203 targeting CREB1 mediated by DNA methylation leads to maintain the malignant biological behaviors of MM cells.

Diferenciação de células-tronco mesenquimais derivadas do tecido adiposo em cardiomiócitos / Differentiation of adipose tissue-derived mesenchymal stem cells into cardiomyocytes

FUNDAMENTO: O potencial de renovação e proliferação dos cardiomiócitos, in vivo, é pequeno, e por isso, o músculo cardíaco apresenta limitada capacidade de repor células perdidas. Na tentativa de minimizar os danos oriundos de lesões hipóxico-isquêmicas e daquelas que acometem o sistema de condução do coração, a terapia celular com células-tronco mesenquimais (MSC) vem sendo utilizada, inclusive com cardiomiócitos diferenciados a partir de MSC. OBJETIVO: O presente trabalho comparou três protocolos distintos de indução de diferenciação objetivando a sugestão de um método viável para a diferenciação de maior número de células funcionais que expressem fenótipo cardiomiogênico. MÉTODOS: Culturas de MSC obtidas de tecido adiposo de ratos jovens da linhagem Lewis transgênicos para proteína verde fluorescente (GFP) foram submetidos a três diferentes meios de diferenciação cardiogênica: Planat-Bérnard, 5-azacitidina e meio Planat-Bérnard + 5-azacitidina e observadas quanto a expressão de marcadores celulares cardíacos. RESULTADOS: Nos três protolocos utilizados observou-se formação da proteína alfa-actinina sarcomérica no citoesqueleto das células submetidas à diferenciação, expressão de conexina 43 na membrana nuclear e citoplasmática e formação de gap junctions, necessárias para a propagação do impulso elétrico no miocárdio, contudo, em nenhum protocolo foi observada contração espontânea das células submetidas à diferenciação cardiogênica. CONCLUSÃO: A indução com 5-azacitidina proporcionou diferenciação celular cadiomiogênica efetiva e similar à encontrada com o meio Planat-Bénard e, por ser um protocolo mais simples, rápido e com menor custo torna-se o método de eleição.

BACKGROUND: Cardiomyocytes have small potential for renovation and proliferation in vivo. Consequently, the heart muscle has limited capacity of self-renewal. Mesenchymal stem cells (MSC) therapy, as well as MSC differentiated into cardiomyocytes, has been used in the attempt to minimize the effects of ischemic-hypoxic lesions and those affecting the electrical conduction system of the heart. OBJECTIVE: The present study compared three distinct protocols for induced differentiation of MSC into cardiomyocytes aimed at finding a viable method for producing a large number of functional cells expressing cardiomyogenic phenotype. METHODS: Mesenchymal stem cells were obtained from the adipose tissue of young transgenic Lewis rats expressing green fluorescent protein (GFP), and submitted to three distinct differentiation-inducing media: 1) Planat-Bérnard, 2) 5-azacytidine, and 3) Planat-Bérnard + 5-azacytidine; further, these cells were identified based on the expression of cardiac cell markers. RESULTS: All three protocols detected the expression of sarcomeric-alpha-actinin protein in the exoskeleton of cells, expression of connexin-43 in the nuclear and cytoplasmic membrane, and formation of gap junctions, which are necessary for electrical impulse propagation in the myocardium. However, no spontaneous cell contraction was observed with any of the tested protocols. CONCLUSION: Induction with 5-azacytidine provided an effective cadiomyogenic cellular differentiation similar to that obtained with Planat-Bénard media. Therefore, 5-azacytidine was the method of choice for being the simplest, fastest and lowest-cost protocol for cell differentiation.

DNA Methylation Changes Following 5-azacitidine Treatment in Patients with Myelodysplastic Syndrome

DNA methyltransferase inhibitor, 5-azacitidine (AC) is effective in myelodysplastic syndromes (MDS) and can induce re-expression in cancer. We analyzed the methylation of 25 tumor suppressor genes in AC-treated MDS. Hypermethylation of CDKN2B, FHIT, ESR1, and IGSF4 gene was detected in 9/44 patients. In concordance with the clinical response, a lack of or decreased methylation in 4 patients with hematologic improvements and persistent methylation in 4 others with no response was observed. The mRNA expression of CDKN2B, IGSF4, and ESR1 was significantly reduced in MDS. Our results suggest that methylation changes contribute to disease pathogenesis and may serve as marker to monitor the efficacy of treatments.

Differential promoter methylation may be a key molecular mechanism in regulating BubR1 expression in cancer cells

The BubR1 mitotic-checkpoint protein monitors proper attachment of microtubules to kinetochores, and links regulation of chromosome-spindle attachment to mitotic-checkpoint signaling. Thus, disruption of BubR1 activity results in a loss of checkpoint control, chromosomal instability caused by a premature anaphase, and/or the early onset of tumorigenesis. The mechanisms by which deregulation and/or abnormalities of BubR1 expression operate, however, remain to be elucidated. In this study, we demonstrate that levels of BubR1 expression are significantly increased by demethylation. Bisulfite sequencing analysis revealed that the methylation status of two CpG sites in the essential BubR1 promoter appear to be associated with BubR1 expression levels. Associations of MBD2 and HDAC1 with the BubR1 promoter were significantly relieved by addition of 5-aza-2'-deoxycytidine, an irreversible DNA methyltransferase inhibitor. However, genomic DNA isolated from 31 patients with colorectal carcinomas exhibited a +84A/G polymorphic change in approximately 60% of patients, but this polymorphism had no effect on promoter activity. Our findings indicate that differential regulation of BubR1 expression is associated with changes in BubR1 promoter hypermethylation patterns, but not with promoter polymorphisms, thus providing a novel insight into the molecular regulation of BubR1 expression in human cancer cells.

5-azacytidine induces cardiac differentiation of P19 embryonic stem cells

The P19 embryonal carcinoma cell line is a useful model cells for studies on cardiac differentiation. However, its low efficacy of differentiation hampers its usefulness. We investigated the effect of 5-azacytidine (5-aza) on P19 cells to differentiate into a high-efficacy cardiomyocytes. Embryoid-body-like structures were formed after 6 days with 1 micrometer of 5-aza in a P19 cell monolayer culture, beating cell clusters first observed on day 12, and, the production of beating cell clusters increased by 80.1% (29 of 36-wells) after 18 days. In comparison, the spontaneous beating cells was 33.3% (12 of 36-wells) for the untreated control cells. In response to 1 micrometer of 5-aza, P19 cells expressed bone morphogenetic protein-2 (BMP-2), BMP-4, Bmpr1a and Smad1 at day 6 or 9, and also cardiac markers such as GATA-4, Nkx2.5, cardiac troponin I, and desmin were up-regulated in a time-dependent manner after induction of BMP signaling molecules. Immunocytochemistry revealed the expression of smooth muscle a-actin, sarcomeric a-actinin, cardiac myosin heavy chain, cardiac troponin T and desmin, respectively. The proportion of sarcomeric a-actinin positive cells accounted for 6.48% on day 15 after 5-aza exposure as measured by flow cytometry. This study has demonstrated that 5-aza induces differentiation of P19 cells into cardiomyocytes in a confluent monolayer culture in the absence of prior embryoid formation and dimethyl sulfoxide exposure, depending in part on alteration of BMP signaling molecules. These results suggest that 5-aza treatment could be used as a new method for cardiac differentiation in P19 cells.

Induced differentiation of human cord blood mesenchymal stem/progenitor cells into cardiomyocyte-like cells in vitro / 华中科技大学学报（医学）（英德文版）

The feasibility of using cord blood mesenchymal stem/progenitor cells (CB-MSPCs) to regenerate cardiomyocytes and the optimal inducing conditions were investigated. The CB mononuclear cells were cultured in low serum DMEM medium to produce an adherent layer. After expansion, the adherent cells were added into cardiomyocyte inducing medium supplemented with 5-azacytidine. Cardiogenic specific contractile protein troponin T staining was performed to identify the cardiomyocyte-like cells. The results showed that the frequency of CB-MSPCs clones in CB mononuclear cells was 0.5 x 10(-6) and about 1.3 x 10(7)-fold expansion was achieved within 20 sub-cultivation. After cardiogenic induction, 70% CB-MSPCs was differentiated into cardiomyocyte-like cells. It was indicated that low serum culture could expand CB-MSPCs extensively and the expanded CB-MSPCs could be induced to differentiate into cardiomyocyte-like cells in high efficiency.

Comparative enzymatic studies on 5-azacytidine pre-treated Biomphalaria Alexandrina snails

Biochemical elucidation of the mode of action of 5-azacytidine on Biomphalaria alexandrina snails, the specific intermediate hosts for Schistosoma mansoni was carried out. The effect of 5-azacytidine on the enzymatic activity of Lactate dehydrogenase [LD], Glucose-6 phosphate dehydrogenase [G - 6 - pd] and on the glutathione content in the haemolymph of the snails is reported