title: MnTMPyP, a metalloporphyrin-based superoxide dismutase/catalase mimetic, protects INS-1 cells and human pancreatic islets from an in vitro oxidative challenge.
abstract: OBJECTIVE
  Pancreatic islets can be lost early following allotransplantation from oxidative stress. Antioxidant enzyme overexpression could confer a beneficial effect on islets exposed to reactive oxygen species (ROS) and nitrogen species. Here, we tested the effect of MnTMPyP, a superoxide dismutase/catalase mimetic.
  
  
  METHODS
  INS-1 insulin-secreting cells or human islets were cultured with MnTMPyP and exposed to a superoxide donor (the hypoxanthine/xanthine oxidase (HX/XO) system), a nitric oxide donor [3-morpholinosydnonimine (SIN-1)] or menadione. Viability of INS-1 cells was assessed by WST-1 colorimetric assay and FACS analysis (Live/Dead test). ROS production was determined using fluorescent probes. Islet viability was estimated by WST-1 assay and endocrine function by static incubation.
  
  
  RESULTS
  Following MnTMPyP treatment, ROS production in INS-1 cells was reduced by 4- to 20-fold upon HX/XO challenge and up to 2-fold upon SIN-1 stress. This phenomenon correlated with higher viability measured by WST-1 or Live/Dead test. MnTMPyP preserved islet viability upon exposure to SIN-1 or menadione but not upon an HX/XO challenge. Similarly, decrease in insulin secretion tended to be less pronounced in MnTMPyP-treated islets than in control islet when exposed to SIN-1, but no changes were noticed during an HX/XO stress.
  
  
  CONCLUSIONS
  MnTMPyP was able to improve the viability of INS-1 cells and human islets exposed to oxidative challenges in vitro. Protection of INS-1 cells could be as high as 90%. This agent is therefore potentially attractive in situations involving the overproduction of ROS, such as islet transplantation.
authors.affiliation: Institut national de la santé et de la recherche médicale (Inserm), unité 578, Grenoble, France.
authors.forename: C
authors.initials: C
authors.lastname: Moriscot
authors.forename: S
authors.initials: S
authors.lastname: Candel
authors.forename: V
authors.initials: V
authors.lastname: Sauret
authors.forename: J
authors.initials: J
authors.lastname: Kerr-Conte
authors.forename: M J
authors.initials: MJ
authors.lastname: Richard
authors.forename: M C
authors.initials: MC
authors.lastname: Favrot
authors.forename: P Y
authors.initials: PY
authors.lastname: Benhamou
mesh_terms: D000818:Animals; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D006801:Humans; D050417:Insulin-Secreting Cells / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D007515:Islets of Langerhans / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D008345:Manganese; D008665:Metalloporphyrins / Q000494:pharmacology*; D018384:Oxidative Stress / Q000187:drug effects*; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D008665:Metalloporphyrins; C502230:Mn(III) 5,10,15,20-tetrakis(N-methylpyridinium-2-yl)porphyrin; D017382:Reactive Oxygen Species; D014665:Vasodilator Agents; D008345:Manganese