Selective expression of TLQP-21 and other VGF peptides in gastric neuroendocrine cells and modulation by feeding.
Although vgf gene knockout mice are hypermetabolic, administration of the VGF peptide TLQP-21 itself increased energy consumption. Agonist-antagonist roles are thus suggested for different VGF peptides, and the definition of their tissue heterogeneity is mandatory. We studied the rat stomach using antisera to C- or N-terminal sequences of known or predicted VGF peptides in immunohistochemistry and ELISA. TLQP (rat VGF(556-565)) peptide/s were most abundant (162±11 pmol/g, mean±s.e.m.) and were brightly immunostained in enterochromaffin-like (ECL) cells and somatostatin cells. A peptide co-eluting with TLQP-21 was revealed in HPLC of gastric and hypothalamic extracts, while the extended TLQP-62 form was restricted to the hypothalamus. Novel PGH (rat VGF(422-430)) peptide/s were revealed in ghrelin cells, mostly corresponding to low MW forms (0.8-1.5  kDa), while VGF C-terminus peptides were confined to neurons. VGF mRNA was present in the above gastric endocrine cell types, and was prominent in chief cells, in parallel with low-intensity staining for further cleaved products from the C-terminal region of VGF (HVLL peptides: VGF(605-614)). In swine stomach, a comparable profile of VGF peptides was revealed by immunohistochemistry. When fed and fasted rats were studied, a clear-cut, selective decrease on fasting was observed for TLQP peptides only (162±11 vs 74±5.3  pmol/g, fed versus fasted rats, mean±s.e.m., P<0.00001). In conclusion, specific VGF peptides appear to be widely represented in different gastric endocrine and other mucosal cell populations. The selective modulation of TLQP peptides suggests their involvement in peripheral neuro-endocrine mechanisms related to feeding responses and/or ECL cell regulation.
Brancia
Carla
C
NEF-Laboratory, Department of Cytomorphology, University of Cagliari, 09042 Monserrato (Cagliari), Italy.
Cocco
Cristina
C
D'Amato
Filomena
F
Noli
Barbara
B
Sanna
Fabrizio
F
Possenti
Roberta
R
Argiolas
Antonio
A
Ferri
Gian-Luca
GL
D000818:Animals; D019872:Chief Cells, Gastric / Q000737:chemistry; D004435:Eating / Q000502:physiology*; D004759:Enterochromaffin Cells / Q000737:chemistry / Q000502:physiology; D005215:Fasting / Q000502:physiology; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism*; D054439:Ghrelin / Q000032:analysis; D007031:Hypothalamus / Q000737:chemistry; D008297:Male; D055099:Neuroendocrine Cells / Q000378:metabolism*; D009479:Neuropeptides / Q000032:analysis / Q000096:biosynthesis*; D010446:Peptide Fragments / Q000032:analysis / Q000096:biosynthesis*; D051381:Rats; D017207:Rats, Sprague-Dawley; D019864:Somatostatin-Secreting Cells / Q000737:chemistry / Q000502:physiology; D013270:Stomach / Q000166:cytology; D013552:Swine
D054439:Ghrelin; D009479:Neuropeptides; D010446:Peptide Fragments; C522412:TLQP-21 peptide; C522413:VGF peptide