Genetic modification of human mesenchymal stem cells helps to reduce adiposity and improve glucose tolerance in an obese diabetic mouse model

Abstract

IntroductionHuman mesenchymal stem cells (MSCs) are multipotent cells that can differentiate into fat, muscle, bone and cartilage cells. Exposure of subcutaneous abdominal adipose tissue derived AD-MSCs to high glucose (HG) leads to superoxide accumulation and up-regulation of inflammatory molecules. Our aim was to inquire how HG exposure affects MSCs differentiation and whether the mechanism is reversible.MethodsWe exposed human adipose tissue derived MSCs to HG (25 mM) and compared it to normal glucose (NG, 5.5 mM) exposed cells at 7, 10 and 14 days. We examined mitochondrial superoxide accumulation (Mitosox-Red), cellular oxygen consumption rate (OCR, Seahorse) and gene expression.ResultsHG increased reactive superoxide (ROS) accumulation noted by day 7 both in cytosol and mitochondria. The OCR between the NG and HG exposed groups however did not change until 10 days at which point OCR of HG exposed cells were reduced significantly. We noted that HG exposure upregulated mRNA expression of adipogenic (PPARG, FABP-4, CREBP alpha and beta), inflammatory (IL-6 and TNF alpha) and antioxidant (SOD2 and Catalase) genes. Next, we used AdSOD2 to upregulate SOD2 prior to HG exposure and thereby noted reduction in superoxide generation. SOD2 upregulation helped reduce mRNA over-expression of PPARG, FABP-4, IL-6 and TNFα. In a series of separate experiments, we delivered the eGFP and SOD2 upregulated MSCs (5 days post ex-vivo transduction) and saline intra-peritoneally (IP) to obese diabetic (db/db) mice. We confirmed homing-in of eGFP labeled MSCs, delivered IP, to different inflamed fat pockets, particularly omental fat. Mice receiving SOD2-MSCs showed progressive reduction in body weight and improved glucose tolerance (GTT) at 4 weeks, post MSCs transplantation compared to the GFP-MSC group (control).ConclusionsHigh glucose evokes superoxide generation, OCR reduction and adipogenic differentiation. Mitochondrial superoxide dismutase upregulation quenches excess superoxide and reduces adipocyte inflammation. Delivery of superoxide dismutase (SOD2) using MSCs as a gene delivery vehicle reduces inflammation and improves glucose tolerance in vivo. Suppression of superoxide production and adipocyte inflammation using mitochondrial superoxide dismutase may be a novel and safe therapeutic tool to combat hyperglycemia mediated effects.

Hyperglycemia‐ and hyperinsulinemia‐induced insulin resistance causes alterations in cellular bioenergetics and activation of inflammatory signaling in lymphatic muscle

“…Our results corroborate well with the findings from various insulin‐resistant tissues or cell types, including human samples. HG‐treated human mesenchymal stem cells from adipose tissue exhibited a decreased OCR in a time‐dependent manner (71). Insulin‐resistant cerebral arteries from obese rats exhibited impairments in mitochondrial functions, coupled with a decrease in mitochondrial proteins (72).…”

Heme oxygenase-1-transduced bone marrow mesenchymal stem cells in reducing acute rejection and improving small bowel transplantation outcomes in rats

“…Cell therapy, particularly in the form of MSCs, has emerged as a novel technique in suppressing the immune response after transplantation, owing to MSCs causing fewer side effects compared with immunosuppressants. While MSCs have been used in multifarious organ transplants [39–41] including SBTx [24, 42], there has been an increased focus on overcoming transplantation limitations and enhancing MSC function [43–47]. This study was designed to investigate whether the cytoprotective and immunosuppressive protein, HO-1, could improve the survival rate of BMMSCs in vivo and reinforce SBTx protection.…”

High Glucose-Induced Reactive Oxygen Species Stimulates Human Mesenchymal Stem Cell Migration Through Snail and EZH2-Dependent E-Cadherin Repression

“…Conversely, other studies have shown that high glucose stimulates proliferation and enhances osteogenic differentiation potential in mesenchymal stem cells (MSCs) [6]. These diverse responses to the high glucose condition may be relevant for the different glucose tolerance of stem cells [7, 8]. Therefore, further investigation into the underlying mechanism of high glucose on stem cell functions is needed to develop a therapeutic strategy for stem cell therapy.…”