Cardiac stem cells: Current knowledge and future prospects

Regenerative medicine is the field concerned with the repair and restoration of the integrity of damaged human tissues as well as whole organs.Since the inception of the field several decades ago,regenerative medicine therapies,namely stem cells,have received significant attention in preclinical studies and clinical trials.Apart from their known potential for differentiation into the various body cells,stem cells enhance the organ's intrinsic regenerative capacity by altering its environment,whether by exogenous injection or introducing their products that modulate endogenous stem cell function and fate for the sake of regeneration.Recently,research in cardiology has highlighted the evidence for the existence of cardiac stem and progenitor cells(CSCs/CPCs).The global burden of cardiovascular diseases’morbidity and mortality has demanded an in-depth understanding of the biology of CSCs/CPCs aiming at improving the outcome for an innovative therapeutic strategy.This review will discuss the nature of each of the CSCs/CPCs,their environment,their interplay with other cells,and their metabolism.In addition,important issues are tackled concerning the potency of CSCs/CPCs in relation to their secretome for mediating the ability to influence other cells.Moreover,the review will throw the light on the clinical trials and the preclinical studies using CSCs/CPCs and combined therapy for cardiac regeneration.Finally,the novel role of nanotechnology in cardiac regeneration will be explored.

Promotive action of 2-acetylaminofluorene on hepatic precancerous lesions initiated by diethylnitrosamine in rats:Molecular study

BACKGROUND Diethylnitrosamine(DEN)induces hepatic neoplastic lesions over a prolonged period.AIM To investigate the promotive action of 2-acetylaminofluorene(2-AAF)when combined with DEN in order to develop a rat model for induction of precancerous lesion and investigate the molecular mechanism underlying the activity of 2-AAF.METHODS The pre-precancerous lesions were initiated by intraperitoneal injection of DEN for three weeks consecutively,followed by one intraperitoneal injection of 2-AAF at three different doses(100,200 and 300 mg/kg).Rats were separated into naïve,DEN,DEN+100 mg 2-AAF,DEN+200 mg 2-AAF,and DEN+300 mg 2-AAF groups.Rats were sacrificed after 10 wk and 16 wk.Liver functions,level of alpha-fetoprotein,glutathione S-transferase-P and proliferating cell nuclear antigen staining of liver tissues were performed.The mRNA level of RAB11A,BAX,p53,and Cyclin E and epigenetic regulation by long-noncoding RNA(lncRNA)RP11-513I15.6,miR-1262(microRNA),and miR-1298 were assessed in the sera and liver tissues of the rats.RESULTS 2-AAF administration significantly increased the percent area of the precancerous foci and cell proliferation along with a significant decrease in RAB11A,BAX,and p53 mRNA,and the increase in Cyclin E mRNA was associated with a marked decrease in lncRNA RP11-513I15.6 expression with a significant increase in both miR-1262 and miR-1298.CONCLUSION 2-AFF promoted hepatic precancerous lesions initiated through DEN by decreasing autophagy,apoptosis,and tumor suppression genes,along with increased cell proliferation,in a time-and dose-dependent manner.These actions were mediated under the epigenetic regulation of lncRNA RP11-513I15.6/miR-1262/miR-1298.

The key role of CYC2 during meiosis in Tetrahymena thermophila

Meiotic recombination is carried out through a special- ized pathway for the formation and repair of DNA dou- ble-strand breaks （DSBs） made by the Spo11 protein. The present study shed light on the functional role of cyclin, CYC2, in Tetrahymena thermophila which has transcriptionally high expression level during meiosis process. Knocking out the CYC2 gene results in arrest of meiotic conjugation process at 2.5-3.5 h after conjugation initiation, before the meiosis division starts, and in company with the absence of DSBs. To investigate the underlying mechanism of this phenomenon, a complete transcriptome profile was performed between wild-type strain and CYC2 knock-out strain. Functional analysis of RNA-Seq results identifies related differentially expressed genes （DEGs） including SP011 and these DEGs are enriched in DNA repair/mismatch repair （MMR） terms in homologous recombination （HR）, which indicates that CYC2 could play a crucial role in meiosis by regulating SP011 and participating in HR.