Dataset Information

Oct4-dependent FoxC1 activation improves the survival and neovascularization of mesenchymal stem cells under myocardial ischemia.

ABSTRACT:

Background

The administration of mesenchymal stem cells (MSCs) remains the most promising approach for cardiac repair after myocardial infarct (MI). However, their poor survival and potential in the ischemic environment limit their therapeutic efficacy for heart repair after MI. The purpose of this study was to investigate the influence of FoxC1-induced vascular niche on the activation of octamer-binding protein 4 (Oct4) and the fate of MSCs under hypoxic/ischemic conditions.

Methods

Vascular microenvironment/niche was induced by efficient delivery of FoxC1 transfection into hypoxic endothelial cells (ECs) or infarcted hearts. MSCs were cultured or injected into this niche by utilizing an in vitro coculture model and a rat MI model. Survival and neovascularization of MSCs regulated by Oct4 were explored using gene transfer and functional studies.

Results

Here, using gene expression heatmap, we demonstrated that cardiac ECs rapidly upregulated FoxC1 after acute ischemic cardiac injury, contributing to an intrinsic angiogenesis. In vitro, FoxC1 accelerated tube-like structure formation and increased survival of ECs, resulting in inducing a vascular microenvironment. Overexpression of FoxC1 in ECs promoted survival and neovascularization of MSCs under hypoxic coculture. Overexpression of Oct4, a FoxC1 target gene, in MSCs enhanced their mesenchymal-to-endothelial transition (MEndoT) while knockdown of Oct4 by siRNA altering vascularization. In a rat MI model, overexpression of FoxC1 in ischemic hearts increased post-infarct vascular density and improved cardiac function. The transplantation of adOct4-pretreated MSCs into these ischemic niches augments MEndoT, enhanced vascularity, and further improved cardiac function. Consistently, these cardioprotective effects of FoxC1 was abrogated when Oct4 was depleted in the MSCs and was mimicked by overexpression of Oct4.

Conclusions

Together, these studies demonstrate that the FoxC1/Oct4 axis is an essential aspect for survival and neovascularization of MSCs in the ischemic conditions and represents a potential therapeutic target for enhancing cardiac repair.

SUBMITTER: Ji Z

PROVIDER: S-EPMC8403428 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Background Cardiac-resident mesenchymal stem cells (cMSCs) can exhibit fibrotic, proinflammatory, and proangiogenic phenotype in response to myocardial ischemia (Isch). How their phenotypic fate decisions are determined remains poorly understood. Here, we demonstrate that the cooperation of Oct4 and c-Myc in cMSCs creates a preferable mesenchymal-to-endothelial transition (MEndoT) to promote angiogenesis and consequent myocardial repair. Methods We collected MSCs from cardiac and peripheral blood of rat with left ventricular Isch (LV Isch) 30 days after myocardial infarction (MI) or sham operation. After a comparison of characterization between cMSCs and peripheral blood MSCs (pbMSCs), we conducted transcriptome analysis and RNA sequencing of cMSCs. Using loss/gain-of-function approaches to understand the cooperation of c-Myc and Oct4 on MEndoT of cMSCs under hypoxic condition, we explored the mechanisms through transcriptome and functional experiment, and chromatin immunoprecipitation. Next, we transplanted male cMSCs with overexpression or inhibition of c-Myc/Oct4 into the infarcted myocardium of female rats and evaluated infarct size, cell retention, inflammation, remodeling, and function after 30 days. Results LV Isch switched cMSCs toward both inflammatory and proangiogenic phenotypes, with increased secretion of inflammatory cytokines as well as decreased expression of proangiogenic factors. The effect of LV Isch on pbMSCs was less remarkable. Gene expression heatmap showed imbalance in expression of Oct4 and c-Myc regulating genes associated with remodeling of cMSCs. We provided evidence that cMSCs-specific c-Myc- versus Oct4-overexpression showed divergent genomic signatures, and their corresponding target genes play an important role in regulating cMSCs phenotypic changes. In particular, Oct4 accelerated angiogenesis induced by c-Myc overexpression in cMSCs and inhibited their phenotypic transition into inflammatory cells and fibroblast. Mechanistically, exogenous Oct4 caused c-Myc to translocate from the nucleus to the cytoplasm and activated some of its target signalings including VEGF signaling. Although transplantation of cMSCs alone did not improve LV remodeling and function, cMSCs co-transfected with c-Myc and Oct4 promoted a more positive effect in their survival and reparative properties, increased animal survival, reduced infarct size, decreased scar thickness, inhibited LV remodeling, and improved heart function 30 days after MI. Significantly, Oct4 promoted MEndoT (“Rescue me” signal) of cMSCs after both c-Myc stimulation in vitro and transplantation into the infarcted heart. Conclusions Myocardial Isch drives resident cMSCs toward multiple phenotypes. Oct4 interacts with c-Myc to promote MEndoT capacity of cMSCs and improve their survival and reparative effects through upregulation of angiogenesis-related signaling pathways. These findings may identify novel targets for stem cell therapy. Supplementary Information The online version contains supplementary material available at 10.1186/s13287-022-03120-7.