ABSTRACT
AIM: To study the effect of calcium sensing receptor (CaSR) on icariin (ICA) induced mouse embryonic stem cells ( mESCs) to differentiate into cardiomyocytes in vitro.METHODS:mESCs were cultured to embry-oid bodies ( EBs) by direct suspension method and the differentiation of EBs into cardiomyocytes was induced by ICA.The expression of cardiac specific proteinsα-actinin and cardiac troponin-I ( cTnI) was analyzed by Western blot and immuno-fluorescence.The differentiation rate was determined by flow cytometry.The ultrastructure of the derived cardiomyocytes was further characterized by transmission electron microscopy.The expression of cardiac-specific transcription factors Nkx2.5 and GATA-4,as well as CaSR was detected by Western blot.RESULTS: After induction with ICA, the positive characteristics of myocardial cells appeared in the EBs cultured for 2 d.The expression of cardiac-specific sarcomeric pro-tein actinin (α-actinin) and cTnI showed an overall upward trend by Western blot in different phases of ICA induced differ-entiation.The expression of CaSR, Nkx2.5 and GATA-4 was the highest at an early stage of ICA-induced differentiation. Neomycin (an activator of CaSR) up-regulated CaSR, NKx2.5 and GATA-4 expression in the EBs at early stage of ICA-in-duced differentiation, all of which were reversed by NPS2390 ( an inhibitor of CaSR) .CONCLUSION:CaSR is function-ally expressed in mESC-derived cardiomyocytes, and activation of CaSR is involved in the differentiation of mESCs into car-diomyocytes by facilitating the expression of NKx2.5 and GATA-4.
ABSTRACT
AIM: Ischemic post-conditioning ( PC) plays an important role in cardioprotection from ischemia /reperfusion ( I/R) injury in the young heart but not in the aging hearts .The physiological and pathological roles of hydrogen sulfide ( H2 S) in the regulation of cardio-vascular functions have been recognized .Whether H2 S is involved in the recovery of PC-induced cardioprotection in the aging hearts is unclear.METHOD:The male Wistar young rats (3-month-old), the aging rats (24-month-old), primary cultured cardiomyocytes and the aging cardiomyocytes induced by D-galactose suffered from I/R (or H/R) and PC.RESULTS:I/R (or H/R) decreased H2S production rate and cystathionine γ-lyase (CSE) expression, aggravated cardiomyocyte damage , apoptosis, myocardial infarct size and oxidative stress, reduced cardiac function, increased the levels of Bcl-2, cleaved caspase-3 and caspase-9 mRNA and proteins, promo-ted the release of cytochrome c and mPTP opening, down-regulated the phosphorylation of ERK 1/2, PI3K, Akt and GSK-3βand mito-chondrial membrane potential , up-regulated the phosphorylation of IκBα, NF-κB, JNK2 and STAT3, and inhibited PKC-ε transloca-tion and mitochondrial ATP-sensitive K channels (mitoKATP) in isolated young and aging hearts as well as normal and aging cardiomyo-cytes.PC suppressed myocardial I/R injury in the young heart but not in the aging hearts .Supply of NaHS not only increased PC-in-duced cardioprotection in the young hearts and cardiomyocytes , but also attenuated I/R injury and significantly recovered the cardiopro-tective role of PC in the aging hearts and cardiomyocytes .CONCLUSION:The exogenous H 2 S restores PC-induced cardioprotection through inhibiting oxidative stress via the down-regulation of NF-κB and JAK2-STAT3 pathways and mPTP opening by the up-regulation of ERK1/2-GSK-3β, PI3K-Akt-GSK-3βand PKC-ε-mitoKATP pathways in the aging hearts and cardiomyocytes .These findings provide a novel potential target for the treatment of aging ischemic cardiomyopathy .
ABSTRACT
AIM: To study the effect of the overexpression of p16 on an anion exchange function of band 3 in HeLa cells. METHODS: The expression of p16 and band 3 in HeLa cells was detected by immunohistochemistry (IHC). The p16 cDNA was subcloned to plasmids pEGFP-C1 by PCR and identified by restriction enzyme digestion and sequencing, and then, the recombinant pEGFP-C1-p16 plasmids were transiently transfected into HeLa cells. The expression of fusion protein in HeLa cells was detected by fluorescence microscope. 6-methoxy-N-(3-sulfopropyl)-quinolinium(SPQ)fluorescent probes were used to detect the anion exchange function of band 3. RESULTS: P16 and band 3 were expressed in HeLa cells. The amplificated p16 cDNA sequence was the same as the report sequence. The transfective efficacy of pEGFP-C1-p16 was above 60%. The anion exchange function increased after the transfection of pEGFP-C1-p16 plasmids. CONCLUSION: p16 facilitates the anion exchange function of band 3 in HeLa cells.