Prolyl Hydroxylase Domain Protein 2 Silencing Enhances the Survival and Paracrine Function of Transplanted Adipose-Derived Stem Cells in Infarcted Myocardium

Abstract

Rationale Transplantation of stem cells into damaged hearts has had modest success as a treatment for ischemic heart disease. One of the limitations is the poor stem cell survival in the diseased microenvironment. Prolyl hydroxylase domain protein 2 (PHD2) is a cellular oxygen sensor that regulates two key transcription factors involved in cell survival and inflammation, hypoxia-inducible factor (HIF) and nuclear factor-κB (NF-κB). Objective We studied if and how PHD2 silencing in human adipose-derived stem cells (ADSCs) enhances their cardioprotective effects after transplantation into infarcted hearts. Methods and Results ADSCs were transduced with lentiviral shPHD2 to silence PHD2. ADSCs with or without shPHD2 were transplanted after myocardial infarction (MI) in mice. ADSCs reduced cardiomyocyte apoptosis, fibrosis and infarct size and improved cardiac function. shPHD2-ADSCs exerted significantly more protection. PHD2 silencing induced greater ADSCs survival, which was abolished by shHIF-1α. Conditioned medium (CM) from shPHD2-ADSCs decreased cardiomyocyte apoptosis. Insulin-like growth factor 1 (IGF-1) levels were significantly higher in the CM of shPHD2-ADSCs versus ADSCs, and depletion of IGF-1 attenuated the cardioprotective effects of shPHD2-ADSCs-CM. NF-κB activation was induced by shPHD2 to induce IGF-1 secretion via binding to IGF-1 gene promoter. Conclusions PHD2 silencing promotes ADSCs survival in MI hearts and enhances their paracrine function to protect cardiomyocytes. The pro-survival effect of shPHD2 on ADSCs is HIF-1α dependent and the enhanced paracrine function of shPHD2-ADSCs is associated with NF-κB-mediated IGF-1 up-regulation. PHD2 silencing in stem cells may be a novel strategy for enhancing the effectiveness of stem cell therapy after MI.

Unique Features of Cortical Bone Stem Cells Associated With Repair of the Injured Heart

“…12,14,33 Communication between the stem cells and myocytes can be achieved by secretion of cardioprotective or angiogenic factors (paracrine signaling) 34 or from direct stem cell, cardiac myocyte, contact. 35 CBSCs can form direct gap junctional connections with AVMs that could enhance their reparative properties.…”

Gastrin Protects Against Myocardial Ischemia/Reperfusion Injury via Activation of RISK (Reperfusion Injury Salvage Kinase) and SAFE (Survivor Activating Factor Enhancement) Pathways

“…Cardiomyocyte apoptosis in paraffin‐embedded sections was detected using an in situ apoptotic cell death detection kit based on the TUNEL (terminal deoxynucleotidyl transferase dUTP nick‐end labeling) assay, following the manufacturer's instructions (Roche) 18, 19. Cardiomyocytes were labeled with antisarcomeric tropomyosin antibody at 4°C overnight, and nuclei were identified with DAPI (4′,6‐diamidino‐2‐phenylindole) staining.…”

“…The expression of tissue protein was measured by immunoblotting, as described previously 19. The total protein concentration was measured using Coomassie brilliant blue.…”

Nanovector-based prolyl hydroxylase domain 2 silencing system enhances the efficiency of stem cell transplantation for infarcted myocardium repair

“…7,8 Recently, it has been demonstrated that lentivirus-based PHD2 silencing in stem cells could enhance the survival of grafted cells in ischemic tissue significantly through a HIF-1α dependent pathway and secretion of insulin-like growth factor-1 (IGF-1) via an NF-κB-mediated mechanism. [9][10][11] However, for clinical application, an effective and safe non-viral PHD-2 silencing system remains in great demand.…”

“…11 In the present study, PHD2 silencing in MSCs was performed using the Arg-G4 nanovector. After transplantation, Group 3 exhibited higher MSC survival rate than Group 2 at any time point from 2 hours to 7 days.…”