Hypoxia Preconditioned Mesenchymal Stem Cells Prevent Cardiac Fibroblast Activation and Collagen Production via Leptin

Abstract

AimsActivation of cardiac fibroblasts into myofibroblasts constitutes a key step in cardiac remodeling after myocardial infarction (MI), due to interstitial fibrosis. Mesenchymal stem cells (MSCs) have been shown to improve post-MI remodeling an effect that is enhanced by hypoxia preconditioning (HPC). Leptin has been shown to promote cardiac fibrosis. The expression of leptin is significantly increased in MSCs after HPC but it is unknown whether leptin contributes to MSC therapy or the fibrosis process. The objective of this study was to determine whether leptin secreted from MSCs modulates cardiac fibrosis.MethodsCardiac fibroblast (CF) activation was induced by hypoxia (0.5% O2). The effects of MSCs on fibroblast activation were analyzed by co-culturing MSCs with CFs, and detecting the expression of α-SMA, SM22α, and collagen IαI in CFs by western blot, immunofluorescence and Sirius red staining. In vivo MSCs antifibrotic effects on left ventricular remodeling were investigated using an acute MI model involving permanent ligation of the left anterior descending coronary artery.ResultsCo-cultured MSCs decreased fibroblast activation and HPC enhanced the effects. Leptin deficit MSCs from Ob/Ob mice did not decrease fibroblast activation. Consistent with this, H-MSCs significantly inhibited cardiac fibrosis after MI and mediated decreased expression of TGF-β/Smad2 and MRTF-A in CFs. These effects were again absent in leptin-deficient MSCs.ConclusionOur data demonstrate that activation of cardiac fibroblast was inhibited by MSCs in a manner that was leptin-dependent. The mechanism may involve blocking TGF-β/Smad2 and MRTF-A signal pathways.

Proteomic Analysis and Identification of Paracrine Factors in Mesenchymal Stem Cell-Conditioned Media under Hypoxia

“…In some reports, TPM isoforms have also been observed on the outside of cells, and cell culture experiments have demonstrated the presence of TPM on the surface of various cells that were derived from the colon, including primary cultures of colonic epithelial cells [33]. Our studies suggest that TPM1 and TPM2 are probably located in extracellular vesicles that are derived from multiple cell and tissue types [34][35][36][37]. These proteins are not generally known as secreted molecules of MSCs, but they could be released via the secretion of extracellular vesicles or exosomes in response to hypoxia.…”

“…A recent study demonstrated that the activation of cardiac fibroblasts was inhibited in leptin-deficient MSCs exposed to hypoxia [34]. The authors found that co-cultured MSCs showed decreased fibroblast activation and that preconditioning the cells with hypoxia enhanced these effects.…”

Novel therapeutic strategies targeting fibroblasts and fibrosis in heart disease

“…Interleukins may act to inhibit cardiac fibroblast proliferation and collagen production as well as myofibroblast differentiation, 171 while MSC-derived leptin was shown to inhibit fibroblast activation by blocking pathways involving TGFβ/‘small mothers against decapentaplegic’ (Smad) and Myocardin-Related Transcription Factor-A. 172 …”

Periadventitial adipose tissue modulates the effect of PROLI/NO on neointimal hyperplasia

“…9 On the other hand, Chen et al has shown that leptin has an inhibitory effect on fibroblast activation. 20 This differential effect of adipokines on VSMC and AF could explain our in vitro findings; VSMC and AF proliferation responded differently to adipocyte-conditioned media. However, in vivo there is a more complex interplay, and adipose-derived leptin has an overall effect that promotes neointimal hyperplasia.…”