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Cruces-Sande M, Arcones AC, Vila-Bedmar R, Val-Blasco A, Sharabi K, Díaz-Rodríguez D, Puigserver P, Mayor F, Murga C. Autophagy mediates hepatic GRK2 degradation to facilitate glucagon-induced metabolic adaptation to fasting. FASEB J 2019; 34:399-409. [PMID: 31914606 DOI: 10.1096/fj.201901444r] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 10/07/2019] [Accepted: 10/21/2019] [Indexed: 12/13/2022]
Abstract
The liver plays a key role during fasting to maintain energy homeostasis and euglycemia via metabolic processes mainly orchestrated by the insulin/glucagon ratio. We report here that fasting or calorie restriction protocols in C57BL6 mice promote a marked decrease in the hepatic protein levels of G protein-coupled receptor kinase 2 (GRK2), an important negative modulator of both G protein-coupled receptors (GPCRs) and insulin signaling. Such downregulation of GRK2 levels is liver-specific and can be rapidly reversed by refeeding. We find that autophagy, and not the proteasome, represents the main mechanism implicated in fasting-induced GRK2 degradation in the liver in vivo. Reducing GRK2 levels in murine primary hepatocytes facilitates glucagon-induced glucose production and enhances the expression of the key gluconeogenic enzyme Pck1. Conversely, preventing full downregulation of hepatic GRK2 during fasting using adenovirus-driven overexpression of this kinase in the liver leads to glycogen accumulation, decreased glycemia, and hampered glucagon-induced gluconeogenesis, thus preventing a proper and complete adaptation to nutrient deprivation. Overall, our data indicate that physiological fasting-induced downregulation of GRK2 in the liver is key for allowing complete glucagon-mediated responses and efficient metabolic adaptation to fasting in vivo.
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Affiliation(s)
- Marta Cruces-Sande
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa (UAM-CSIC), Madrid, Spain.,Instituto de Investigación Sanitaria La Princesa, Madrid, Spain.,CIBER de Enfermedades Cardiovasculares (CIBERCV), ISCIII, Madrid, Spain
| | - Alba C Arcones
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa (UAM-CSIC), Madrid, Spain.,Instituto de Investigación Sanitaria La Princesa, Madrid, Spain.,CIBER de Enfermedades Cardiovasculares (CIBERCV), ISCIII, Madrid, Spain
| | - Rocío Vila-Bedmar
- Departamento de ciencias básicas de la salud, área de Bioquímica y Biología Molecular, URJC, Madrid, Spain
| | - Almudena Val-Blasco
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa (UAM-CSIC), Madrid, Spain.,Instituto de Investigación Sanitaria La Princesa, Madrid, Spain.,CIBER de Enfermedades Cardiovasculares (CIBERCV), ISCIII, Madrid, Spain
| | - Kfir Sharabi
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA.,Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Daniel Díaz-Rodríguez
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa (UAM-CSIC), Madrid, Spain
| | - Pere Puigserver
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA.,Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Federico Mayor
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa (UAM-CSIC), Madrid, Spain.,Instituto de Investigación Sanitaria La Princesa, Madrid, Spain.,CIBER de Enfermedades Cardiovasculares (CIBERCV), ISCIII, Madrid, Spain
| | - Cristina Murga
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa (UAM-CSIC), Madrid, Spain.,Instituto de Investigación Sanitaria La Princesa, Madrid, Spain.,CIBER de Enfermedades Cardiovasculares (CIBERCV), ISCIII, Madrid, Spain
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Tanemura K, Ohtaki T, Ono M, Tsumagari S. Development of ovarian diseases in dairy cows with a history of fatty liver, and their prognosis. J Vet Med Sci 2016; 78:755-60. [PMID: 26781845 PMCID: PMC4905827 DOI: 10.1292/jvms.14-0637] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In the present report, the incidence and prognosis of ovarian diseases were evaluated in correlation to the grades of the fatty livers (FL). 233 animals were diagnosed with a FL, based on fat deposition of >10% into the hepatic parenchyma obtained from liver biopsy, and were eventually cured of the FL. These 233 animals were classified into mild group (n=99: hepatic fat deposition rates ranging from 10 to <30%), moderate group (n=56: hepatic fat deposition rates ranging from 30 to <60%) and severe group (n=78: hepatic fat deposition rates of >60%). The incidence of ovarian diseases and the culling rate were, respectively, 40.0% and 10.0% in mild group, 58.3% and 37.5% in moderate group, and 84.9% and 69.7% in severe group. The incidence of ovarian diseases and the culling rates in severe group were significantly (P<0.05) higher than those in mild and moderate groups. It was, therefore, concluded that the elevated incidence of ovarian disease and culling rates tend to be dependent on the higher severity scores of the fat deposition rates in dairy cows with FL and that cases with severe FL, with a fat deposition rate of 60% or higher, were greatly associated with death and culling.
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Affiliation(s)
- Kouichi Tanemura
- Laboratory of Theriogenology, College of Bioresouce Sciences, Nihon University, 1866 Kameino, Fujisawa, Kanagawa 252-0880, Japan
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Ying S, Wang Z, Wang C, Nie H, He D, Jia R, Wu Y, Wan Y, Zhou Z, Yan Y, Zhang Y, Wang F. Effect of different levels of short-term feed intake on folliculogenesis and follicular fluid and plasma concentrations of lactate dehydrogenase, glucose, and hormones in Hu sheep during the luteal phase. Reproduction 2011; 142:699-710. [PMID: 21893609 DOI: 10.1530/rep-11-0229] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This study investigated the effects of short-term food restriction or supplementation on folliculogenesis and plasma and intrafollicular metabolite and hormone concentrations. Ewes were randomly assigned to three groups: the control group received a maintenance diet (M) while the supplemented group and restricted group received 1.5×M and 0.5×M respectively on days 6-12 of their estrous cycle. Estrus was synchronized by intravaginal progestogen sponges for 12 days. On days 7-12, blood samples were taken. After slaughter, the ovarian follicles were classified and the follicular fluid was collected. Compared with restriction, supplementation shortened the estrous cycle length, decreased the number of follicles 2.5-3.5 mm and follicular fluid estradiol (E2) concentration, increased the number of follicles>3.5 mm and plasma glucose, insulin and glucagon concentrations, and augmented the volume of follicles>2.5 mm. Restricted ewes had higher intrafollicular insulin concentration, but it was similar to that of supplemented ewes. Compared with follicles≤2.5 mm, the intrafollicular glucose and E2 concentrations were increased and the testosterone, insulin, and glucagon concentrations and lactate dehydrogenase (LDH) activity were decreased in follicles>2.5 mm. Only in restricted ewes were intrafollicular LDH and testosterone concentrations in follicles≤2.5 mm not different from those in follicles≤2.5 mm. In conclusion, the mechanism by which short-term dietary restriction inhibits folliculogenesis may involve responses to intrafollicular increased E2, testosterone, and LDH levels in late-stage follicles. This may not be due to the variation of intrafollicular insulin level but rather due to decreased circulating levels of glucose, insulin, and glucagon.
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Affiliation(s)
- Shijia Ying
- Institute of Sheep and Goat Science, Center of Animal Embryo Engineering and Technology, Nanjing Agricultural University, Jiangsu, Nanjing 210095, China
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Longuet C, Sinclair EM, Maida A, Baggio LL, Maziarz M, Charron MJ, Drucker DJ. The glucagon receptor is required for the adaptive metabolic response to fasting. Cell Metab 2008; 8:359-71. [PMID: 19046568 PMCID: PMC2593715 DOI: 10.1016/j.cmet.2008.09.008] [Citation(s) in RCA: 144] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2007] [Revised: 06/03/2008] [Accepted: 09/12/2008] [Indexed: 10/21/2022]
Abstract
Glucagon receptor (Gcgr) signaling maintains hepatic glucose production during the fasting state; however, the importance of the Gcgr for lipid metabolism is unclear. We show here that fasted Gcgr-/- mice exhibit a significant increase in hepatic triglyceride secretion and fasting increases fatty acid oxidation (FAO) in wild-type (WT) but not in Gcgr-/- mice. Moreover fasting upregulated the expression of FAO-related hepatic mRNA transcripts in Gcgr+/+ but not in Gcgr-/- mice. Exogenous glucagon administration reduced plasma triglycerides in WT mice, inhibited TG synthesis and secretion, and stimulated FA beta oxidation in Gcgr+/+ hepatocytes. The actions of glucagon on TG synthesis and FAO were abolished in PPARalpha-/- hepatocytes. These findings demonstrate that the Gcgr receptor is required for control of lipid metabolism during the adaptive metabolic response to fasting.
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Affiliation(s)
- Christine Longuet
- Department of Medicine, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, University of Toronto, Toronto, Ontario M5G 1X5, Canada
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