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.
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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

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Figure 3

α-MSH is a substrate of PRCP.

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α-MSH is a substrate of PRCP. (A and B) Changes in body weight and food ...
(A and B) Changes in body weight and food intake of Prcpgt/gt mice and wild-type controls exposed to HFD. Data represent the mean ± SEM. (C) Increasing concentrations of α-MSH1–13, α-MSH1–12, or Ang II (0.001–1 mM) were incubated with 8 nM of rPRCP51 at 37°C in microtiter plate cuvette wells with preabsorbed HK and containing 20 nM PK. The liberation of paranitroanilide (pNA) from the S2302 by the formed plasma kallikrein in the presence of the peptide was measured at 405 nm. Results are expressed as residual formed plasma kallikrein activity. The data represent the mean ± SEM of 3 independent measurements. (D and E) Food intake in grams 4 hours after an i.p. injection of 200 nmol of α-MSH1–13 or 200 nmol of MTII in wild-type (D) or Prcpgt/gt mice (E) compared with saline-injected control animals. Data represent the mean ± SEM. *P < 0.001 compared with saline; #P < 0.001 compared with α-MSH.