Identification and characterization of nesfatin-1 immunoreactivity in endocrine cell types of the rat gastric oxyntic mucosa.
Hypothalamic nesfatin-1, derived from the nucleobindin2 (NUCB2) precursor, inhibits nocturnal food intake and body weight gain in rats. Nesfatin-1 is able to cross the blood-brain barrier, suggesting a peripheral source of nesfatin-1. Many centrally acting food intake regulatory neuropeptides are also produced in the periphery, especially in the gastrointestinal tract. Therefore, we investigated the gene expression of NUCB2 and distribution of nesfatin-1-immunoreactive cells in the stomach. Microarray mRNA expression profiles in purified small endocrine cells of the gastric mucosa substantiated by quantitative RT-PCR showed significantly higher NUCB2 mRNA expression compared with brain and heart. Western blot confirmed the expression of NUCB2 protein and its transport into a secretory soluble fraction of gastric mucosal endocrine cell homogenates. Immunohistochemical colabeling for nesfatin-1 and ghrelin, histidine decarboxylase, or somatostatin revealed two subtypes of nesfatin-1-positive endocrine cells. Cells in the midportion of the glands coexpressed nesfatin-1 and ghrelin, whereas few cells in the glandular base coexpressed nesfatin-1 and somatostatin or histidine decarboxylase. High-resolution three-dimensional volume imaging revealed two separate populations of intracytoplasmic vesicles in these cells, one containing nesfatin-1 and the other ghrelin immunoreactivity. Microarray rat genome expression data of NUCB2 in small gastric endocrine cells confirmed by quantitative RT-PCR showed significant down-regulation of NUCB2 after 24 h fasting. In summary, NUCB2 mRNA expression as well as protein content is present in a specific subset of gastric endocrine cells, most of which coexpress ghrelin. NUCB2 gene expression is significantly regulated by nutritional status, suggesting a regulatory role of peripheral nesfatin-1 in energy homeostasis.
Stengel
Andreas
A
CURE/Digestive Diseases Research Center, Center for Neurobiology of Stress, Digestive Diseases Division, Department of Medicine, University of California, Los Angeles, California, USA.
Goebel
Miriam
M
Yakubov
Iskandar
I
Wang
Lixin
L
Witcher
Derrick
D
Coskun
Tamer
T
Taché
Yvette
Y
Sachs
George
G
Lambrecht
Nils W G
NW
D000818:Animals; D002135:Calcium-Binding Proteins / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics; D002149:Energy Intake; D005753:Gastric Mucosa / Q000166:cytology*; D054439:Ghrelin / Q000378:metabolism; D006640:Histidine Decarboxylase / Q000378:metabolism; D007150:Immunohistochemistry; D008297:Male; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism*; D000080866:Nucleobindins; D020411:Oligonucleotide Array Sequence Analysis; D010179:Pancreas / Q000166:cytology; D010295:Parietal Cells, Gastric / Q000166:cytology*; D010902:Pituitary Gland / Q000166:cytology; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013004:Somatostatin / Q000378:metabolism; D015430:Weight Gain
D002135:Calcium-Binding Proteins; D004268:DNA-Binding Proteins; D054439:Ghrelin; D009419:Nerve Tissue Proteins; C000630652:Nucb1 protein, rat; D000080866:Nucleobindins; D013004:Somatostatin; D012313:RNA; D006640:Histidine Decarboxylase