miR-133a Enhances the Protective Capacity of Cardiac Progenitors Cells after Myocardial Infarction
Summary 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 vasculari…
Identification and Characterization of the Dermal Panniculus Carnosus Muscle Stem Cells
Summary The dermal Panniculus carnosus (PC) muscle is important for wound contraction in lower mammals and represents an interesting model of muscle regeneration due to its high cell turnover. The resident satellite cells (the bona fide muscle stem cells) remain poorly characterized. Here we analyzed PC satellite cells with regard to developmental origin and purported function. Lineage tracing shows that they originate in Myf5+, Pax3/Pax7+ cell populations. Skin and muscle wounding increased PC myofiber turnover, with the satellite cell progeny being involved in muscle regeneration but with no detectable contribution to the wound-bed myofibroblasts. Since hematopoietic stem cells fuse to PC…
Deficient p27 Phosphorylation at Serine 10 Increases Macrophage Foam Cell Formation and Aggravates Atherosclerosis Through a Proliferation-Independent Mechanism
OBJECTIVE: Genetic ablation of the growth suppressor p27(Kip1) (p27) in the mouse aggravates atherosclerosis coinciding with enhanced arterial cell proliferation. However, it is unknown whether molecular mechanisms that limit p27's protective function contribute to atherosclerosis development and whether p27 exerts proliferation-independent activities in the arterial wall. This study aims to provide insight into both questions by investigating the role in atherosclerosis of p27 phosphorylation at serine 10 (p27-phospho-Ser10), a major posttranslational modification of this protein. METHODS AND RESULTS: Immunoblotting studies revealed a marked reduction in p27-phospho-Ser10 in atheroscleroti…