Prolylcarboxypeptidase regulates food intake by inactivating α-MSH in rodents
Nicholas Wallingford, … , Craig H. Warden, Sabrina Diano
Nicholas Wallingford, … , Craig H. Warden, Sabrina Diano
Published July 20, 2009
Citation Information: J Clin Invest. 2009;119(8):2291-2303. https://doi.org/10.1172/JCI37209.
View: Text | PDF
Research Article

Prolylcarboxypeptidase regulates food intake by inactivating α-MSH in rodents

Abstract

The anorexigenic neuromodulator α-melanocyte–stimulating hormone (α-MSH; referred to here as α-MSH1–13) undergoes extensive posttranslational processing, and its in vivo activity is short lived due to rapid inactivation. The enzymatic control of α-MSH1–13 maturation and inactivation is incompletely understood. Here we have provided insight into α-MSH1–13 inactivation through the generation and analysis of a subcongenic mouse strain with reduced body fat compared with controls. Using positional cloning, we identified a maximum of 6 coding genes, including that encoding prolylcarboxypeptidase (PRCP), in the donor region. Real-time PCR revealed a marked genotype effect on Prcp mRNA expression in brain tissue. Biochemical studies using recombinant PRCP demonstrated that PRCP removes the C-terminal amino acid of α-MSH1–13, producing α-MSH1–12, which is not neuroactive. We found that Prcp was expressed in the hypothalamus in neuronal populations that send efferents to areas where α-MSH1–13 is released from axon terminals. The inhibition of PRCP activity by small molecule protease inhibitors administered peripherally or centrally decreased food intake in both wild-type and obese mice. Furthermore, Prcp-null mice had elevated levels of α-MSH1–13 in the hypothalamus and were leaner and shorter than the wild-type controls on a regular chow diet; they were also resistant to high-fat diet–induced obesity. Our results suggest that PRCP is an important component of melanocortin signaling and weight maintenance via control of active α-MSH1–13 levels.

Authors

Nicholas Wallingford, Bertrand Perroud, Qian Gao, Anna Coppola, Erika Gyengesi, Zhong-Wu Liu, Xiao-Bing Gao, Adam Diament, Kari A. Haus, Zia Shariat-Madar, Fakhri Mahdi, Sharon L. Wardlaw, Alvin H. Schmaier, Craig H. Warden, Sabrina Diano

×

Figure 5

Hypothalamic localization of PRCP.

Options: View larger image (or click on image) Download as PowerPoint
Hypothalamic localization of PRCP. (A) Dark blue β-gal labeling represen...
(A) Dark blue β-gal labeling representing LacZ expression in the place of PRCP in cells of the hypothalamus. Most labeled cells are in the vicinity of the DMH, perifornical region (pf), LH, and zona incerta (ZI). A few labeled cells are also visible in the arcuate nucleus (ARC) of the mediobasal hypothalamus. f, fornix; III, third ventricle. (B) Corresponding to the LacZ expression shown in A, in situ hybridization for PRCP mRNA in wild-type animals resulted in labeled cells (dark-field micrograph; white dots represent digoxigenin labeling of antisense mRNA probe) in the DMH, pf, LH, and ZI, with a few labeled cells also present in the ARC. (C–F) Double labeling for β-gal (LacZ) and MCH or Hcrt revealed extensive coexpression of PRCP and MCH (C) and PRCP and Hcrt in the LH perifornical region (D). A few cells expressing POMC were also found to express LacZ (representing PRCP) in the arcuate nucleus (F). (E) LacZ-positive boutons in close proximity to α-MSH–immunopositive terminals in the hypothalamic PVN. Red arrows indicate double-labeled cells; black arrows point to single-labeled LacZ-expressing cells; and black arrowheads indicate single-labeled POMC, MCH, or Hcrt neurons. Scale bar in A (also applies to B): 100 μm. Scale bar in C (also applies to D and F): 10 μm. Scale bar in E: 2 μm.