title: Genetic modification of human mesenchymal stem cells helps to reduce adiposity and improve glucose tolerance in an obese diabetic mouse model.
abstract: BACKGROUND
  Human 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.
  
  
  METHODS
  We 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.
  
  
  RESULTS
  HG 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).
  
  
  CONCLUSIONS
  High 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.
authors.affiliation: Department of Medicine, Division of Endocrinology and Metabolism, The George Washington University, School of Medicine and Health Sciences, 2300 I Street, Ross Hall Suite: 450, Washington, DC, 20037, USA. ssen1@gwu.edu.
authors.forename: Sabyasachi
authors.initials: S
authors.lastname: Sen
authors.affiliation: Department of Medicine, Division of Endocrinology and Metabolism, The George Washington University, School of Medicine and Health Sciences, 2300 I Street, Ross Hall Suite: 450, Washington, DC, 20037, USA. cleytoncd@gwu.edu.
authors.forename: Cleyton C
authors.initials: CC
authors.lastname: Domingues
authors.affiliation: Department of Medicine, Division of Endocrinology and Metabolism, The George Washington University, School of Medicine and Health Sciences, 2300 I Street, Ross Hall Suite: 450, Washington, DC, 20037, USA. carorouphael@gmail.com.
authors.forename: Carol
authors.initials: C
authors.lastname: Rouphael
authors.affiliation: Pioneer Valley Life Sciences Institute, and Division of Endocrinology, Diabetes & Metabolism at Baystate Medical Center of Tufts University School of Springfield, Springfield, MA, USA. cyril.chou@tufts.edu.
authors.forename: Cyril
authors.initials: C
authors.lastname: Chou
authors.affiliation: Pioneer Valley Life Sciences Institute, and Division of Endocrinology, Diabetes & Metabolism at Baystate Medical Center of Tufts University School of Springfield, Springfield, MA, USA. chulkim501@gmail.com.
authors.forename: Chul
authors.initials: C
authors.lastname: Kim
authors.affiliation: Pioneer Valley Life Sciences Institute, and Division of Endocrinology, Diabetes & Metabolism at Baystate Medical Center of Tufts University School of Springfield, Springfield, MA, USA. nagendra.yadava@baystatehealth.org.
authors.forename: Nagendra
authors.initials: N
authors.lastname: Yadava
mesh_terms: D050154:Adiposity / Q000235:genetics*; D000818:Animals; D001823:Body Composition; D002478:Cells, Cultured; D003921:Diabetes Mellitus, Experimental / Q000235:genetics / Q000378:metabolism / Q000628:therapy*; D042967:Electron Transport Complex I / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D005951:Glucose Tolerance Test; D006801:Humans; D006943:Hyperglycemia / Q000235:genetics / Q000378:metabolism; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism*; D051379:Mice; D009765:Obesity / Q000235:genetics / Q000378:metabolism / Q000628:therapy*; D018384:Oxidative Stress; D010101:Oxygen Consumption; D013482:Superoxide Dismutase / Q000235:genetics; D000099156:Superoxide Dismutase 2
chemical_list: D042967:Electron Transport Complex I; D005947:Glucose; D013482:Superoxide Dismutase; D000099156:Superoxide Dismutase 2