title: NADPH Oxidase-Dependent Reactive Oxygen Species Stimulate β-Cell Regeneration Through Differentiation of Endocrine Progenitors in Murine Pancreas.
abstract: OBJECTIVE
  Reactive oxygen species (ROS) act as second messengers for redox modification of transcription factors essential for differentiation. The nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, a major source of ROS, has been shown to regulate differentiation of various progenitor cells, while its role in pancreatic endocrine cell differentiation is unclear. This study was aimed at this knowledge gap.
  
  
  RESULTS
  Our results showed that ROS levels were dynamically changed during pancreas development concomitant with endocrine cell differentiation induced by modest exogenous ROS in rudiment cultures. NOX4, but not NOX2, the member of NADPH oxidase, was expressed persistently in endocrine lineage and showed high activity in critical pancreas development phase. Inhibition of NADPH oxidase activity impeded the differentiation of endocrine progenitors in vitro, and exogenous ROS reversed this effect. Studies performed in streptozotocin (STZ)-injected neonatal rats showed that diphenyleneiodonium (DPI) obstructed β-cell regeneration through the suppression of neurogenin 3 (NGN3) expression, but not Ki67-labeling β-cells, indicating that ROS stimulation promoted differentiation beyond proliferation of β-cells. Inhibition of NADPH oxidase also reduced expression of SRY (sex-determining region Y)-box 9 (SOX9), a transcriptional regulator of Ngn3, in endocrine precursor cells, both in vivo and in vitro. Overexpression of SOX9 attenuated the reduction of NGN3 induced by suppression of NADPH oxidase.
  
  
  CONCLUSIONS
  This is the first study to demonstrate NADPH oxidase, especially NOX4-dependent ROS that promotes pancreatic progenitor cell differentiation into endocrine cells both in vitro and in vivo, probably through the regulation of SOX9. We provide evidence that NADPH oxidase-dependent ROS-mediated signaling is necessary for endocrine cell differentiation, which provides a potential strategy for efficient generation of insulin-producing cells in clinical application.
authors.affiliation: School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong , Hong Kong, China .
authors.forename: Juan
authors.initials: J
authors.lastname: Liang
authors.affiliation: School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong , Hong Kong, China .
authors.forename: Shang Ying
authors.initials: SY
authors.lastname: Wu
authors.affiliation: School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong , Hong Kong, China .
authors.forename: Dan
authors.initials: D
authors.lastname: Zhang
authors.affiliation: School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong , Hong Kong, China .
authors.forename: Lin
authors.initials: L
authors.lastname: Wang
authors.affiliation: School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong , Hong Kong, China .
authors.forename: Kwan Keung
authors.initials: KK
authors.lastname: Leung
authors.affiliation: School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong , Hong Kong, China .
authors.forename: Po Sing
authors.initials: PS
authors.lastname: Leung
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D005786:Gene Expression Regulation / Q000187:drug effects; D050417:Insulin-Secreting Cells / Q000166:cytology* / Q000378:metabolism; D008297:Male; D051379:Mice; D019255:NADPH Oxidases / Q000378:metabolism*; D009861:Onium Compounds / Q000494:pharmacology*; D010179:Pancreas / Q000166:cytology / Q000254:growth & development; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction; D013311:Streptozocin / Q000008:administration & dosage*
chemical_list: D009861:Onium Compounds; D017382:Reactive Oxygen Species; D013311:Streptozocin; C007517:diphenyleneiodonium; D019255:NADPH Oxidases