miRNA-1 and miRNA-133a are involved in early commitment of pluripotent stem cells and demonstrate antagonistic roles in the regulation of cardiac differentiation.

miRNA-1 (miR-1) and miRNA-133a (miR-133a) are muscle-specific miRNAs that play an important role in heart development and physiopathology. Although both miRNAs have been broadly studied during cardiogenesis, the mechanisms by which miR-1 and miR-133a could influence linage commitment in pluripotent stem cells remain poorly characterized. In this study we analysed the regulation of miR-1 and miR-133a expression during pluripotent stem cell differentiation [P19.CL6 cells; embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs)] and investigated their role in DMSO and embryoid body (EB)-mediated mesodermal and cardiac differentiation by gain- and loss-of-function studies, as well as in vivo, by the induction of teratomas. Gene expression analysis revealed that miR-1 and miR-133a are upregulated during cardiac differentiation of P19.CL6 cells, and also during ESC and iPSC EB differentiation. Forced overexpression of both miRNAs promoted mesodermal commitment and a concomitant decrease in the expression of neural differentiation markers. Moreover, overexpression of miR-1 enhanced the cardiac differentiation of P19.CL6, while miR-133a reduced it with respect to control cells. Teratoma formation experiments with P19.CL6 cells confirmed the influence of miR-1 and miR-133a during in vivo differentiation. Finally, inhibition of both miRNAs during P19.CL6 cardiac differentiation had opposite results to their overexpression. In conclusion, gene regulation involving miR-1 and miR-133a controls the mesodermal and cardiac fate of pluripotent stem cells. Copyright © 2014 John Wiley & Sons, Ltd.

Podocalyxin-like protein 1 is a relevant marker for human c-kit(pos) cardiac stem cells.

Cardiac progenitor cells (CPCs) from adult myocardium offer an alternative cell therapy approach for ischaemic heart disease. Improved clinical performance of CPCs in clinical trials requires a comprehensive definition of their biology and specific interactions with the environment. In this work we characterize specific human CPC surface markers and study some of their related functions. c-kit(pos) human CPCs (hCPCs) were characterized for cell surface marker expression, pluripotency, early and late cardiac differentiation markers and therapeutic activity in a rat model of acute myocardial infarction. The results indicate that hCPCs are a mesenchymal stem cell (MSC)-like population, with a similar immunoregulatory capacity. A partial hCPC membrane proteome was analysed by liquid chromatography-mass spectrometry/mass spectrometry and 36 proteins were identified. Several, including CD26, myoferlin and podocalyxin-like protein 1 (PODXL), have been previously described in other stem-cell systems. Suppression and overexpression analysis demonstrated that PODXL regulates hCPC activation, migration and differentiation; it also modulates their local immunoregulatory capacity. Therefore, hCPCs are a resident cardiac population that shares many features with hMSCs, including their capacity for local immunoregulation. Expression of PODXL appears to favour the immature state of hCPCs, while its downregulation facilitates their differentiation. Copyright © 2016 John Wiley & Sons, Ltd.

Cholesterol control according to the presence of metabolic syndrome in coronary and diabetic patients. Relationship with non-alcoholic fatty liver disease.

BACKGROUND AND AIMS: Metabolic syndrome (MS) is an association of cardiovascular risk factors that increases the risk of coronary disease or type 2 diabetes mellitus (DM2), and has also been associated with the presence of liver steatosis (LS). In this study the relation of MS and LS with cholesterol control was analyzed in very high cardiovascular risk patients (coronary patients and/or DM2). METHODS: A cross-sectional epidemiological study including 6988 patients, from whom information was obtained on their characteristics, lipid profile and treatments. RESULTS: 4455 patients (65%) of the total study population had MS. Of MS criteria, high BP was the criterion most represented in the total population, while high TGs was the least. Within the total population, coronary patients showed a greater proportion of high BP, high TG and low HDL-c than those without coronary disease. Although no influence of MS was seen on the achievement of LDL-c targets (<70 mg/dL), the presence of high BP, high blood glucose and low HDL-c was related to poorer control of LDL-c. Finally, patients with MS showed a greater proportion of liver steatosis and this was associated in turn with poorer control of LDL-c. CONCLUSIONS: The criteria for MS are closely related to cholesterol control. LS is more prevalent in patients with MS, and it is associated with poorer control of LDL-c. We should focus on the presence of MS in high and very high CV risk patients in order to improve their lipid control.

miR-133a enhances the protective capacity of cardiac progenitors cells after myocardial infarction.

miR-133a and miR-1 are known as muscle-specific microRNAs that are involved in cardiac development and pathophysiology. We have shown that both miR-1 and miR-133a are early and progressively upregulated during in vitro cardiac differentiation of adult cardiac progenitor cells (CPCs), but only miR-133a expression was enhanced under in vitro oxidative stress. miR-1 was demonstrated to favor differentiation of CPCs, whereas miR-133a overexpression protected CPCs against cell death, targeting, among others, the proapoptotic genes Bim and Bmf. miR-133a-CPCs clearly improved cardiac function in a rat myocardial infarction model by reducing fibrosis and hypertrophy and increasing vascularization and cardiomyocyte proliferation. The beneficial effects of miR-133a-CPCs seem to correlate with the upregulated expression of several relevant paracrine factors and the plausible cooperative secretion of miR-133a via exosomal transport. Finally, an in vitro heart muscle model confirmed the antiapoptotic effects of miR-133a-CPCs, favoring the structuration and contractile functionality of the artificial tissue.

Complement anaphylatoxins C3a and C5a induce a failing regenerative program in cardiac resident cells. Evidence of a role for cardiac resident stem cells other than cardiomyocyte renewal.

Cardiac healing, which follows myocardial infarction, is a complex process guided by intricate interactions among different components. Some resident cell populations with a potential role in cardiac healing have already been described in cardiac tissues. These non-cardiomyocyte cell subsets, globally described as cardiac pluripotent/progenitor cells (CPCs), are able to differentiate into all three major cardiac cell lineages (endothelial, smooth muscle and cardiomyocyte cells) in experimental settings. Nevertheless, physiological cardiac healing results in a fibrous scar, which remains to be fully modelled experimentally. Since a role for complement anaphylatoxins (C3a and C5a) has been described in several regeneration/repair processes, we examined the effects that C3a and C5a exert on a defined population of CPCs. We found that C3a and C5a are able to enhance CPC migration and proliferation. In vitro studies showed that this effect is linked to activation of telomerase mRNA and partial preservation of telomere length, in an NFκB-dependent manner. In addition, anaphylatoxin signalling modulates the CPC phenotype, increasing myofibroblast differentiation and reducing endothelial and cardiac gene expression. These findings may denote that C3a and C5a are able to maintain/increase the cardiac stem cell pool within the heart, whilst simultaneously facilitating and modulating resident cell differentiation. We found that this modulation was directed towards scar forming cells, which increased fibroblast/myofibroblast generation and suggests that both these anaphylatoxins could play a relevant role in the damage-coupled activation of resident cells, and regulation of the cardiac healing process after injury.

Cardiac stem cell genetic engineering using the alphaMHC promoter.

AIMS: Cardiac stem cells (CSCs) show potential as a cellular therapeutic approach to blunt tissue damage and facilitate reparative and regenerative processes after myocardial infarction. Despite multiple published reports of improvement, functional benefits remain modest using normal stem cells delivered by adoptive transfer into damaged myocardium. The goal of this study is to enhance survival and proliferation of CSCs that have undergone lineage commitment in early phases as evidenced by expression of proteins driven by the alpha-myosin heavy chain (alphaMHC) promoter. The early increased expression of survival kinases augments expansion of the cardiogenic CSC pool and subsequent daughter progeny. MATERIALS & METHODS: Normal CSCs engineered with fluorescent reporter protein constructs under control of the alphaMHC promoter show transgene protein expression, confirming activity of the promoter in CSCs. Cultured CSCs from both nontransgenic and cardiac-specific transgenic mice expressing survival kinases driven by the alphaMHC promoter were analyzed to characterize transgene expression following treatments to promote differentiation in culture. RESULTS & CONCLUSION: Therapeutic genes controlled by the alphaMHC promoter can be engineered into and expressed in CSCs and cardiomyocyte progeny with the goal of improving the efficacy of cardiac stem cell therapy.