title: MicroRNA 375 mediates palmitate-induced enteric neuronal damage and high-fat diet-induced delayed intestinal transit in mice.
abstract: OBJECTIVE
  A high-fat diet (HFD) can cause serious health problems, including alteration of gastrointestinal transit, the exact mechanism of which is not clear. Several microRNAs (miRNAs) are involved in energy homeostasis, lipid metabolism, and HFD-induced weight gain. We investigated the role of miRNAs in HFD-induced damage to the enteric nervous system.
  
  
  METHODS
  Male mice were fed a HFD (60% calories from fat) or regular diets (18% calories from fat) for 11 weeks. Mice on regular diets and HFDs were given intraperitoneal injections of Mir375 inhibitor or a negative control. Body weights, food intake, stool indices, and gastrointestinal transit (following Evans blue gavage) were measured. An enteric neuronal cell line (immorto-fetal enteric neuronal) and primary enteric neurons were used for in vitro studies.
  
  
  RESULTS
  HFD delayed intestinal transit, which was associated with increased apoptosis and loss of colonic myenteric neurons. Mice fed a low-palmitate HFD did not develop a similar phenotype. Palmitate caused apoptosis of enteric neuronal cells associated with mitochondrial dysfunction and endoplasmic reticulum stress. Palmitate significantly increased the expression of Mir375 in vitro; transfection of cells with a Mir375 inhibitor prevented the palmitate-induced enteric neuronal cell apoptosis. Mir375 expression was increased in myenteric ganglia of mice fed HFD and associated with decreased levels of Mir375 target messenger RNAs, including Pdk1. Systemic injection of a Mir375 inhibitor for 5 weeks prevented HFD-induced delay in intestinal transit and morphologic changes.
  
  
  CONCLUSIONS
  HFDs delay colonic transit, partly by inducing apoptosis in enteric neuronal cells. This effect is mediated by Mir375 and is associated with reduced levels of Pdk1. Mir375 might be targeted to increase survival of enteric neurons and gastrointestinal motility.
authors: Department of Digestive Diseases, Emory University School of Medicine, Atlanta, Georgia; Atlanta VA Medical Center, Decatur, Georgia.
authors: Behtash Ghazi
authors: BG
authors: Nezami
authors: Department of Digestive Diseases, Emory University School of Medicine, Atlanta, Georgia; Atlanta VA Medical Center, Decatur, Georgia.
authors: Simon M
authors: SM
authors: Mwangi
authors: Department of Digestive Diseases, Emory University School of Medicine, Atlanta, Georgia; Atlanta VA Medical Center, Decatur, Georgia.
authors: Jai Eun
authors: JE
authors: Lee
authors: Department of Digestive Diseases, Emory University School of Medicine, Atlanta, Georgia; Atlanta VA Medical Center, Decatur, Georgia.
authors: Sabrina
authors: S
authors: Jeppsson
authors: Department of Digestive Diseases, Emory University School of Medicine, Atlanta, Georgia; Atlanta VA Medical Center, Decatur, Georgia.
authors: Mallappa
authors: M
authors: Anitha
authors: Department of Digestive Diseases, Emory University School of Medicine, Atlanta, Georgia; Atlanta VA Medical Center, Decatur, Georgia.
authors: Shadi S
authors: SS
authors: Yarandi
authors: Department of Pathology and Laboratory Medicine, Emory University, Atlanta, Georgia.
authors: Alton B
authors: AB
authors: Farris
authors: Department of Digestive Diseases, Emory University School of Medicine, Atlanta, Georgia; Atlanta VA Medical Center, Decatur, Georgia. Electronic address: ssrini2@emory.edu.
authors: Shanthi
authors: S
authors: Srinivasan
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology; D015415:Biomarkers / Q000378:metabolism; D002460:Cell Line; D003106:Colon / Q000294:innervation / Q000473:pathology / Q000503:physiopathology; D059305:Diet, High-Fat / Q000009:adverse effects*; D004041:Dietary Fats / Q000009:adverse effects*; D017615:Enteric Nervous System / Q000473:pathology* / Q000503:physiopathology; D005772:Gastrointestinal Transit / Q000502:physiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009474:Neurons / Q000473:pathology* / Q000502:physiology; D010168:Palmitates / Q000009:adverse effects*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D011897:Random Allocation; D013312:Stress, Physiological
chemical_list: D015415:Biomarkers; D004041:Dietary Fats; D035683:MicroRNAs; C540349:Mirn375 microRNA, mouse; D010168:Palmitates; C000631433:Pdk1 protein, mouse; D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D017346:Protein Serine-Threonine Kinases
keywords: 3-phosphoinositide-dependent protein kinase-1; ChAT; ENS; ER; FFAs; FITC; GI; Gastrointestinal; HFD; Hyperlipidemia; LP-HFD; MicroRNAs; Motility; NADPH diaphorase; Pdk1; RD; SOD; choline acetyltransferase; endoplasmic reticulum; enteric nervous system; fluorescein isothiocyanate; free fatty acids; gastrointestinal; high-fat diet; low-palmitate HFD; mRNA; messenger RNA; miRNAs; microRNAs; nicotinamide adenine dinucleotide phosphate; regular diet; superoxide dismutase