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Niraula A, Fasnacht RD, Ness KM, Frey JM, Cuschieri SA, Dorfman MD, Thaler JP. Prostaglandin PGE2 Receptor EP4 Regulates Microglial Phagocytosis and Increases Susceptibility to Diet-Induced Obesity. Diabetes 2023; 72:233-244. [PMID: 36318114 PMCID: PMC10090268 DOI: 10.2337/db21-1072] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 10/23/2022] [Indexed: 11/06/2022]
Abstract
In rodents, susceptibility to diet-induced obesity requires microglial activation, but the molecular components of this pathway remain incompletely defined. Prostaglandin PGE2 levels increase in the mediobasal hypothalamus during high-fat-diet (HFD) feeding, and the PGE2 receptor EP4 regulates microglial activation state and phagocytic activity, suggesting a potential role for microglial EP4 signaling in obesity pathogenesis. To test the role of microglial EP4 in energy balance regulation, we analyzed the metabolic phenotype in a microglia-specific EP4 knockout (MG-EP4 KO) mouse model. Microglial EP4 deletion markedly reduced weight gain and food intake in response to HFD feeding. Corresponding with this lean phenotype, insulin sensitivity was also improved in HFD-fed MG-EP4 KO mice, though glucose tolerance remained surprisingly unaffected. Mechanistically, EP4-deficient microglia showed an attenuated phagocytic state marked by reduced CD68 expression and fewer contacts with pro-opiomelanocortin (POMC) neuron processes. These cellular changes observed in the MG-EP4 KO mice corresponded with an increased density of POMC neurites extending into the paraventricular nucleus (PVN). These findings reveal that microglial EP4 signaling promotes body weight gain and insulin resistance during HFD feeding. Furthermore, the data suggest that curbing microglial phagocytic function may preserve POMC cytoarchitecture and PVN input to limit overconsumption during diet-induced obesity.
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Affiliation(s)
- Anzela Niraula
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA
- Department of Medicine, University of Washington, Seattle, WA
| | - Rachael D. Fasnacht
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA
- Department of Medicine, University of Washington, Seattle, WA
| | - Kelly M. Ness
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA
- Department of Medicine, University of Washington, Seattle, WA
| | - Jeremy M. Frey
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA
- Department of Medicine, University of Washington, Seattle, WA
| | - Sophia A. Cuschieri
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA
- Department of Medicine, University of Washington, Seattle, WA
| | - Mauricio D. Dorfman
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA
- Department of Medicine, University of Washington, Seattle, WA
| | - Joshua P. Thaler
- UW Medicine Diabetes Institute, University of Washington, Seattle, WA
- Department of Medicine, University of Washington, Seattle, WA
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Yu M, Bean JC, Liu H, He Y, Yang Y, Cai X, Yu K, Pei Z, Liu H, Tu L, Conde KM, Wang M, Li Y, Yin N, Zhang N, Han J, Scarcelli NA, Xu P, He Y, Xu Y, Wang C. SK3 in POMC neurons plays a sexually dimorphic role in energy and glucose homeostasis. Cell Biosci 2022; 12:170. [PMID: 36210455 PMCID: PMC9549684 DOI: 10.1186/s13578-022-00907-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 09/27/2022] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND Pro-opiomelanocortin (POMC) neurons play a sexually dimorphic role in body weight and glucose balance. However, the mechanisms for the sex differences in POMC neuron functions are not fully understood. RESULTS We detected small conductance calcium-activated potassium (SK) current in POMC neurons. Secondary analysis of published single-cell RNA-Seq data showed that POMC neurons abundantly express SK3, one SK channel subunit. To test whether SK3 in POMC neurons regulates POMC neuron functions on energy and glucose homeostasis, we used a Cre-loxP strategy to delete SK3 specifically from mature POMC neurons. POMC-specific deletion of SK3 did not affect body weight in either male or female mice. Interestingly, male mutant mice showed not only decreased food intake but also decreased physical activity, resulting in unchanged body weight. Further, POMC-specific SK3 deficiency impaired glucose balance specifically in female mice but not in male mice. Finally, no sex differences were detected in the expression of SK3 and SK current in total POMC neurons. However, we found higher SK current but lower SK3 positive neuron population in male POMC neurons co-expressing estrogen receptor α (ERα) compared to that in females. CONCLUSION These results revealed a sexually dimorphic role of SK3 in POMC neurons in both energy and glucose homeostasis independent of body weight control, which was associated with the sex difference of SK current in a subpopulation of POMC + ERα + neurons.
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Affiliation(s)
- Meng Yu
- grid.39382.330000 0001 2160 926XChildren’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA
| | - Jonathan C. Bean
- grid.39382.330000 0001 2160 926XChildren’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA
| | - Hailan Liu
- grid.39382.330000 0001 2160 926XChildren’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA
| | - Yang He
- grid.39382.330000 0001 2160 926XChildren’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA
| | - Yongjie Yang
- grid.39382.330000 0001 2160 926XChildren’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA
| | - Xing Cai
- grid.39382.330000 0001 2160 926XChildren’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA
| | - Kaifan Yu
- grid.39382.330000 0001 2160 926XChildren’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA
| | - Zhou Pei
- grid.39382.330000 0001 2160 926XChildren’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA
| | - Hesong Liu
- grid.39382.330000 0001 2160 926XChildren’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA
| | - Longlong Tu
- grid.39382.330000 0001 2160 926XChildren’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA
| | - Kristine M. Conde
- grid.39382.330000 0001 2160 926XChildren’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA
| | - Mengjie Wang
- grid.39382.330000 0001 2160 926XChildren’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA
| | - Yongxiang Li
- grid.39382.330000 0001 2160 926XChildren’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA
| | - Na Yin
- grid.39382.330000 0001 2160 926XChildren’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA
| | - Nan Zhang
- grid.39382.330000 0001 2160 926XChildren’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA
| | - Junying Han
- grid.39382.330000 0001 2160 926XChildren’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA
| | - Nikolas A. Scarcelli
- grid.39382.330000 0001 2160 926XChildren’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA
| | - Pingwen Xu
- grid.185648.60000 0001 2175 0319Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, The University of Illinois at Chicago, Chicago, IL 60612 USA
| | - Yanlin He
- grid.64337.350000 0001 0662 7451Pennington Biomedical Research Center, Brain glycemic and metabolism control department, Louisiana State University, Baton Rouge, LA 70808 USA
| | - Yong Xu
- grid.39382.330000 0001 2160 926XChildren’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA ,grid.39382.330000 0001 2160 926XDepartment of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA
| | - Chunmei Wang
- grid.39382.330000 0001 2160 926XChildren’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA
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Wang W, Xu M, Yue J, Zhang Q, Nie X, Jin Y, Zhang Z. Knockdown of Acid-sensing Ion Channel 1a in the PVN Promotes Metabolic Disturbances in Male Mice. Endocrinology 2022; 163:6650558. [PMID: 35894166 DOI: 10.1210/endocr/bqac115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Indexed: 11/19/2022]
Abstract
Increasing incidence of metabolic disturbances has become a severe public healthcare problem. Ion channels and receptors in the paraventricular nucleus (PVN) of the hypothalamus serve vital roles in modulating neuronal activities and endocrine functions, which are linked to the regulation of energy balance and glucose metabolism. In this study, we found that acid-sensing ion channel 1a (ASIC1a), a Ca2+-permeable cationic ion channel was localized in the PVN. Knockdown of ASIC1a in this region led to significant body weight gain, glucose intolerance, and insulin resistance. Pharmacological inhibition of ASIC1a resulted in an increase in food intake and a decrease in energy expenditure. Our findings suggest ASIC1a in the PVN as a potential new target for the therapeutic intervention of metabolic disorders.
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Affiliation(s)
- Wei Wang
- Department of Endocrinology and Laboratory for Diabetes, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Mengyun Xu
- Institute of Endocrine and Metabolic Diseases, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Jiayin Yue
- Department of Endocrinology and Laboratory for Diabetes, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Qilun Zhang
- Department of Endocrinology and Laboratory for Diabetes, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Xiaomin Nie
- Department of Endocrinology and Laboratory for Diabetes, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Yan Jin
- Stroke Center and Department of Neurology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Zhi Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
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Pei Z, He Y, Bean JC, Yang Y, Liu H, Yu M, Yu K, Hyseni I, Cai X, Liu H, Qu N, Tu L, Conde KM, Wang M, Li Y, Yin N, Zhang N, Han J, Potts CHS, Scarcelli NA, Yan Z, Xu P, Wu Q, He Y, Xu Y, Wang C. Gabra5 plays a sexually dimorphic role in POMC neuron activity and glucose balance. Front Endocrinol (Lausanne) 2022; 13:889122. [PMID: 36120438 PMCID: PMC9471380 DOI: 10.3389/fendo.2022.889122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 08/15/2022] [Indexed: 11/25/2022] Open
Abstract
Pro-opiomelanocortin (POMC) neurons are important for the regulation of body weight and glucose balance. The inhibitory tone to POMC neurons is mediated primarily by the GABA receptors. However, the detailed mechanisms and functions of GABA receptors are not well understood. The α5 subunit of GABAA receptor, Gabra5, is reported to regulate feeding, and we found that Gabra5 is highly expressed in POMC neurons. To explore the function of Gabra5 in POMC neurons, we knocked down Gabra5 specifically from mature hypothalamic POMC neurons using the clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 strategy. This POMC-specific knock-down of Gabra5 did not affect body weight or food intake in either male or female mice. Interestingly, the loss of Gabra5 caused significant increases in the firing frequency and resting membrane potential, and a decrease in the amplitude of the miniature inhibitory postsynaptic current (mIPSC) in male POMC neurons. However, the loss of Gabra5 only modestly decreased the frequency of mIPSC in female POMC neurons. Consistently, POMC-specific knock-down of Gabra5 significantly improved glucose tolerance in male mice but not in female mice. These results revealed a sexually dimorphic role of Gabra5 in POMC neuron activity and glucose balance, independent of body weight control.
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Affiliation(s)
- Zhou Pei
- Department of Endocrinology and Inherited Metabolic Diseases, Children’s Hospital of Fudan University, Shanghai, China
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - Yang He
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - Jonathan C. Bean
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - Yongjie Yang
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - Hailan Liu
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - Meng Yu
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - Kaifan Yu
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - Ilirjana Hyseni
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - Xing Cai
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - Hesong Liu
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - Na Qu
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - Longlong Tu
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - Kristine M. Conde
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - Mengjie Wang
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - Yongxiang Li
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - Na Yin
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - Nan Zhang
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - Junying Han
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - Camille HS. Potts
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - Nikolas A. Scarcelli
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - Zili Yan
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - Pingwen Xu
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, The University of Illinois at Chicago, Chicago, IL, United States
| | - Qi Wu
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - Yanlin He
- Pennington Biomedical Research Center, Brain Glycemic and Metabolism Control Department, Louisiana State University, Baton Rouge, LA, United States
| | - Yong Xu
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, United States
| | - Chunmei Wang
- Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
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Banerjee J, Dorfman MD, Fasnacht R, Douglass JD, Wyse-Jackson AC, Barria A, Thaler JP. CX3CL1 Action on Microglia Protects from Diet-Induced Obesity by Restoring POMC Neuronal Excitability and Melanocortin System Activity Impaired by High-Fat Diet Feeding. Int J Mol Sci 2022; 23:6380. [PMID: 35742824 PMCID: PMC9224384 DOI: 10.3390/ijms23126380] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 05/31/2022] [Accepted: 06/04/2022] [Indexed: 02/04/2023] Open
Abstract
Both hypothalamic microglial inflammation and melanocortin pathway dysfunction contribute to diet-induced obesity (DIO) pathogenesis. Previous studies involving models of altered microglial signaling demonstrate altered DIO susceptibility with corresponding POMC neuron cytological changes, suggesting a link between microglia and the melanocortin system. We addressed this hypothesis using the specific microglial silencing molecule, CX3CL1 (fractalkine), to determine whether reducing hypothalamic microglial activation can restore POMC/melanocortin signaling to protect against DIO. We performed metabolic analyses in high fat diet (HFD)-fed mice with targeted viral overexpression of CX3CL1 in the hypothalamus. Electrophysiologic recording in hypothalamic slices from POMC-MAPT-GFP mice was used to determine the effects of HFD feeding and microglial silencing via minocycline or CX3CL1 on GFP-labeled POMC neurons. Finally, mice with hypothalamic overexpression of CX3CL1 received central treatment with the melanocortin receptor antagonist SHU9119 to determine whether melanocortin signaling is required for the metabolic benefits of CX3CL1. Hypothalamic overexpression of CX3CL1 increased leptin sensitivity and POMC gene expression, while reducing weight gain in animals fed an HFD. In electrophysiological recordings from hypothalamic slice preparations, HFD feeding was associated with reduced POMC neuron excitability and increased amplitude of inhibitory postsynaptic currents. Microglial silencing using minocycline or CX3CL1 treatment reversed these HFD-induced changes in POMC neuron electrophysiologic properties. Correspondingly, blockade of melanocortin receptor signaling in vivo prevented both the acute and chronic reduction in food intake and body weight mediated by CX3CL1. Our results show that suppressing microglial activation during HFD feeding reduces DIO susceptibility via a mechanism involving increased POMC neuron excitability and melanocortin signaling.
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Affiliation(s)
- Jineta Banerjee
- Department of Medicine, Division of Metabolism, Endocrinology and Nutrition, University of Washington Medicine Diabetes Institute, University of Washington, Seattle, WA 98109, USA; (J.B.); (M.D.D.); (R.F.); (J.D.D.); (A.C.W.-J.)
| | - Mauricio D. Dorfman
- Department of Medicine, Division of Metabolism, Endocrinology and Nutrition, University of Washington Medicine Diabetes Institute, University of Washington, Seattle, WA 98109, USA; (J.B.); (M.D.D.); (R.F.); (J.D.D.); (A.C.W.-J.)
| | - Rachael Fasnacht
- Department of Medicine, Division of Metabolism, Endocrinology and Nutrition, University of Washington Medicine Diabetes Institute, University of Washington, Seattle, WA 98109, USA; (J.B.); (M.D.D.); (R.F.); (J.D.D.); (A.C.W.-J.)
| | - John D. Douglass
- Department of Medicine, Division of Metabolism, Endocrinology and Nutrition, University of Washington Medicine Diabetes Institute, University of Washington, Seattle, WA 98109, USA; (J.B.); (M.D.D.); (R.F.); (J.D.D.); (A.C.W.-J.)
| | - Alice C. Wyse-Jackson
- Department of Medicine, Division of Metabolism, Endocrinology and Nutrition, University of Washington Medicine Diabetes Institute, University of Washington, Seattle, WA 98109, USA; (J.B.); (M.D.D.); (R.F.); (J.D.D.); (A.C.W.-J.)
| | - Andres Barria
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98109, USA;
| | - Joshua P. Thaler
- Department of Medicine, Division of Metabolism, Endocrinology and Nutrition, University of Washington Medicine Diabetes Institute, University of Washington, Seattle, WA 98109, USA; (J.B.); (M.D.D.); (R.F.); (J.D.D.); (A.C.W.-J.)
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6
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Maunze B, Bruckner KW, Desai NN, Chen C, Chen F, Baker D, Choi S. Pituitary adenylate cyclase-activating polypeptide receptor activation in the hypothalamus recruits unique signaling pathways involved in energy homeostasis. Am J Physiol Endocrinol Metab 2022; 322:E199-E210. [PMID: 35001657 PMCID: PMC8897015 DOI: 10.1152/ajpendo.00320.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Pituitary adenylate cyclase activating polypeptide (PACAP) exerts pleiotropic effects on ventromedial nuclei (VMN) of the hypothalamus and its control of feeding and energy expenditure through the type I PAC1 receptor (PAC1R). However, the endogenous role of PAC1Rs in the VMN and the downstream signaling responsible for PACAP's effects on energy balance are unknown. Numerous studies have revealed that PAC1Rs are coupled to both Gαs/adenylyl cyclase/protein kinase A (Gαs/AC/PKA) and Gαq/phospholipase C/protein kinase C (Gαq/PLC/PKC), while also undergoing trafficking following stimulation. To determine the endogenous role of PAC1Rs and downstream signaling that may explain PACAP's pleiotropic effects, we used RNA interference to knockdown VMN PAC1Rs and pharmacologically inhibited PKA, PKC, and PAC1R trafficking. Knocking down PAC1Rs increased meal sizes, reduced total number of meals, and induced body weight gain. Inhibition of either PKA or PKC alone in awake male Sprague-Dawley rats, attenuated PACAP's hypophagic and anorectic effects during the dark phase. However, PKA or PKC inhibition potentiated PACAP's thermogenic effects during the light phase. Analysis of locomotor activity revealed that PKA inhibition augmented PACAP's locomotor effects, whereas PKC inhibition had no effect. Finally, PACAP administration in the VMN induces surface PAC1R trafficking into the cytosol which was blocked by endocytosis inhibitors. Subsequently, inhibition of PAC1R trafficking into the cytosol attenuated PACAP-induced hypophagia. These results revealed that endogenous PAC1Rs uniquely engage PKA, PKC, and receptor trafficking to mediate PACAP's pleiotropic effects in VMN control of feeding and metabolism.NEW & NOTEWORTHY Endogenous PAC1 receptors, integral to VMN management of feeding behavior and body weight regulation, uniquely engage PKA, PKC, and receptor trafficking to mediate the hypothalamic ventromedial nuclei control of feeding and metabolism. PACAP appears to use different signaling mechanisms to regulate feeding behavior from its effects on metabolism.
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Affiliation(s)
- Brian Maunze
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin
| | | | - Nikhil Nilesh Desai
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin
| | - Christopher Chen
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin
| | - Fanghong Chen
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin
| | - David Baker
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin
| | - SuJean Choi
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin
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7
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Vohra MS, Benchoula K, Serpell CJ, Hwa WE. AgRP/NPY and POMC neurons in the arcuate nucleus and their potential role in treatment of obesity. Eur J Pharmacol 2022; 915:174611. [PMID: 34798121 DOI: 10.1016/j.ejphar.2021.174611] [Citation(s) in RCA: 47] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 10/27/2021] [Accepted: 10/27/2021] [Indexed: 02/08/2023]
Abstract
Obesity is a major health crisis affecting over a third of the global population. This multifactorial disease is regulated via interoceptive neural circuits in the brain, whose alteration results in excessive body weight. Certain central neuronal populations in the brain are recognised as crucial nodes in energy homeostasis; in particular, the hypothalamic arcuate nucleus (ARC) region contains two peptide microcircuits that control energy balance with antagonistic functions: agouti-related peptide/neuropeptide-Y (AgRP/NPY) signals hunger and stimulates food intake; and pro-opiomelanocortin (POMC) signals satiety and reduces food intake. These neuronal peptides levels react to energy status and integrate signals from peripheral ghrelin, leptin, and insulin to regulate feeding and energy expenditure. To manage obesity comprehensively, it is crucial to understand cellular and molecular mechanisms of information processing in ARC neurons, since these regulate energy homeostasis. Importantly, a specific strategy focusing on ARC circuits needs to be devised to assist in treating obese patients and maintaining weight loss with minimal or no side effects. The aim of this review is to elucidate the recent developments in the study of AgRP-, NPY- and POMC-producing neurons, specific to their role in controlling metabolism. The impact of ghrelin, leptin, and insulin signalling via action of these neurons is also surveyed, since they also impact energy balance through this route. Lastly, we present key proteins, targeted genes, compounds, drugs, and therapies that actively work via these neurons and could potentially be used as therapeutic targets for treating obesity conditions.
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Affiliation(s)
- Muhammad Sufyan Vohra
- School of Medicine, Faculty of Health and Medical Sciences, Taylor's University Lakeside Campus, 47500, Subang Jaya, Selangor Darul Ehsan, Malaysia
| | - Khaled Benchoula
- School of Medicine, Faculty of Health and Medical Sciences, Taylor's University Lakeside Campus, 47500, Subang Jaya, Selangor Darul Ehsan, Malaysia
| | - Christopher J Serpell
- School of Physical Sciences, Ingram Building, University of Kent, Canterbury, Kent, CT2 7NH, United Kingdom
| | - Wong Eng Hwa
- School of Medicine, Faculty of Health and Medical Sciences, Taylor's University Lakeside Campus, 47500, Subang Jaya, Selangor Darul Ehsan, Malaysia.
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Tang Q, Liu Q, Yang X, Wu T, Huang C, Zhang J, Zhang Z, Zhang G, Zhao Y, Zhou J, Huang H, Xia Y, Yan J, Li Y, He J. Sirtuin 6 supra-physiological overexpression in hypothalamic pro-opiomelanocortin neurons promotes obesity via the hypothalamus-adipose axis. FASEB J 2021; 35:e21408. [PMID: 33583107 DOI: 10.1096/fj.202002607] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Accepted: 01/19/2021] [Indexed: 02/05/2023]
Abstract
Sirtuin 6 (Sirt6), a member of the Sirtuin family, has important roles in maintaining glucose and lipid metabolism. Our previous studies demonstrated that the deletion of Sirt6 in pro-opiomelanocortin (POMC)-expressing cells by the loxP-Cre system resulted in severe obesity and hepatic steatosis. However, whether overexpression of Sirt6 in hypothalamic POMC neurons could ameliorate diet-induced obesity is still unknown. Thus, we generated mice specifically overexpressing Sirt6 in hypothalamic POMC neurons (PSOE) by stereotaxic injection of Cre-dependent adeno-associated viruses into the arcuate nucleus of Pomc-Cre mice. PSOE mice showed increased adiposity and decreased energy expenditure. Furthermore, thermogenesis of BAT and lipolysis of WAT were both impaired, caused by reduced sympathetic nerve innervation and activity in adipose tissues. Mechanistically, Sirt6 overexpression decreasing STAT3 acetylation, thus lowering POMC expression in the hypothalamus underlined the observed phenotypes in PSOE mice. These results demonstrate that Sirt6 overexpression specifically in the hypothalamic POMC neurons exacerbates diet-induced obesity and metabolic disorders via the hypothalamus-adipose axis.
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Affiliation(s)
- Qin Tang
- Laboratory of Clinical Pharmacy and Adverse Drug Reaction, West China Hospital of Sichuan University, Chengdu, China
| | - Qinhui Liu
- Laboratory of Clinical Pharmacy and Adverse Drug Reaction, West China Hospital of Sichuan University, Chengdu, China
| | - Xuping Yang
- Laboratory of Clinical Pharmacy and Adverse Drug Reaction, West China Hospital of Sichuan University, Chengdu, China
- Department of Pharmacy, West China Hospital of Sichuan University, Chengdu, China
| | - Tong Wu
- Laboratory of Clinical Pharmacy and Adverse Drug Reaction, West China Hospital of Sichuan University, Chengdu, China
- Department of Pharmacy, West China Hospital of Sichuan University, Chengdu, China
| | - Cuiyuan Huang
- Laboratory of Clinical Pharmacy and Adverse Drug Reaction, West China Hospital of Sichuan University, Chengdu, China
- Department of Pharmacy, West China Hospital of Sichuan University, Chengdu, China
| | - Jinhang Zhang
- Laboratory of Clinical Pharmacy and Adverse Drug Reaction, West China Hospital of Sichuan University, Chengdu, China
- Department of Pharmacy, West China Hospital of Sichuan University, Chengdu, China
| | - Zijing Zhang
- Laboratory of Clinical Pharmacy and Adverse Drug Reaction, West China Hospital of Sichuan University, Chengdu, China
- Department of Pharmacy, West China Hospital of Sichuan University, Chengdu, China
| | - Guorong Zhang
- Laboratory of Clinical Pharmacy and Adverse Drug Reaction, West China Hospital of Sichuan University, Chengdu, China
- Department of Pharmacy, West China Hospital of Sichuan University, Chengdu, China
| | - Yingnan Zhao
- Laboratory of Clinical Pharmacy and Adverse Drug Reaction, West China Hospital of Sichuan University, Chengdu, China
- Department of Pharmacy, West China Hospital of Sichuan University, Chengdu, China
| | - Jian Zhou
- Laboratory of Clinical Pharmacy and Adverse Drug Reaction, West China Hospital of Sichuan University, Chengdu, China
- Department of Pharmacy, West China Hospital of Sichuan University, Chengdu, China
| | - Hui Huang
- Laboratory of Clinical Pharmacy and Adverse Drug Reaction, West China Hospital of Sichuan University, Chengdu, China
- Department of Pharmacy, West China Hospital of Sichuan University, Chengdu, China
| | - Yan Xia
- Laboratory of Clinical Pharmacy and Adverse Drug Reaction, West China Hospital of Sichuan University, Chengdu, China
- Department of Pharmacy, West China Hospital of Sichuan University, Chengdu, China
| | - Jiamin Yan
- Laboratory of Clinical Pharmacy and Adverse Drug Reaction, West China Hospital of Sichuan University, Chengdu, China
- Department of Pharmacy, West China Hospital of Sichuan University, Chengdu, China
| | - Yanping Li
- Laboratory of Clinical Pharmacy and Adverse Drug Reaction, West China Hospital of Sichuan University, Chengdu, China
| | - Jinhan He
- Laboratory of Clinical Pharmacy and Adverse Drug Reaction, West China Hospital of Sichuan University, Chengdu, China
- Department of Pharmacy, West China Hospital of Sichuan University, Chengdu, China
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9
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Pražienková V, Funda J, Pirník Z, Karnošová A, Hrubá L, Kořínková L, Neprašová B, Janovská P, Benzce M, Kadlecová M, Blahoš J, Kopecký J, Železná B, Kuneš J, Bardová K, Maletínská L. GPR10 gene deletion in mice increases basal neuronal activity, disturbs insulin sensitivity and alters lipid homeostasis. Gene 2021; 774:145427. [PMID: 33450349 DOI: 10.1016/j.gene.2021.145427] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 11/27/2020] [Accepted: 01/05/2021] [Indexed: 02/07/2023]
Abstract
G-protein-coupled receptor GPR10 is expressed in brain areas regulating energy metabolism. In this study, the effects of GPR10 gene deficiency on energy homeostasis in mice of both sexes fed either standard chow or a high-fat diet (HFD) were studied, with a focus on neuronal activation of PrRP neurons, and adipose tissue and liver metabolism. GPR10 deficiency in males upregulated the phasic and tonic activity of PrRP neurons in the nucleus of the solitary tract. GPR10 knockout (KO) males on a standard diet displayed a higher body weight than their wild-type (WT) littermates due to an increase in adipose tissue mass; however, HFD feeding did not cause weight differences between genotypes. Expression of lipogenesis genes was suppressed in the subcutaneous adipose tissue of GPR10 KO males. In contrast, GPR10 KO females did not differ in body weight from their WT controls, but showed elevated expression of lipid metabolism genes in the liver and subcutaneous adipose tissue compared to WT controls. An attenuated non-esterified fatty acids change after glucose load compared to WT controls suggested a defect in insulin-mediated suppression of lipolysis in GPR10 KO females. Indirect calorimetry did not reveal any differences in energy expenditure among groups. In conclusion, deletion of GPR10 gene resulted in changes in lipid metabolism in mice of both sexes, however in different extent. An increase in adipose tissue mass observed in only GPR10 KO males may have been prevented in GPR10 KO females owing to a compensatory increase in the expression of metabolic genes.
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Affiliation(s)
- Veronika Pražienková
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, 16610 Prague, Czech Republic
| | - Jiří Funda
- Institute of Physiology of the Czech Academy of Sciences, 14200 Prague, Czech Republic
| | - Zdenko Pirník
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, 16610 Prague, Czech Republic; Biomedical Research Center SAS of the Slovak Academy of Sciences, 845 05 Bratislava, Slovak Republic; Institute of Physiology, Faculty of Medicine, Comenius University in Bratislava, 813 72 Bratislava, Slovak Republic
| | - Alena Karnošová
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, 16610 Prague, Czech Republic
| | - Lucie Hrubá
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, 16610 Prague, Czech Republic
| | - Lucia Kořínková
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, 16610 Prague, Czech Republic
| | - Barbora Neprašová
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, 16610 Prague, Czech Republic
| | - Petra Janovská
- Institute of Physiology of the Czech Academy of Sciences, 14200 Prague, Czech Republic
| | - Michal Benzce
- Institute of Physiology of the Czech Academy of Sciences, 14200 Prague, Czech Republic
| | - Michaela Kadlecová
- Institute of Physiology of the Czech Academy of Sciences, 14200 Prague, Czech Republic
| | - Jaroslav Blahoš
- Institute of Molecular Genetics of the Czech Academy of Sciences, 14220 Prague, Czech Republic
| | - Jan Kopecký
- Institute of Physiology of the Czech Academy of Sciences, 14200 Prague, Czech Republic
| | - Blanka Železná
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, 16610 Prague, Czech Republic
| | - Jaroslav Kuneš
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, 16610 Prague, Czech Republic; Institute of Physiology of the Czech Academy of Sciences, 14200 Prague, Czech Republic
| | - Kristina Bardová
- Institute of Physiology of the Czech Academy of Sciences, 14200 Prague, Czech Republic
| | - Lenka Maletínská
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, 16610 Prague, Czech Republic.
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10
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Christie S, O'Rielly R, Li H, Nunez-Salces M, Wittert GA, Page AJ. Modulatory effect of methanandamide on gastric vagal afferent satiety signals depends on nutritional status. J Physiol 2020; 598:2169-2182. [PMID: 32237243 DOI: 10.1113/jp279449] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Accepted: 03/25/2020] [Indexed: 12/18/2022] Open
Abstract
SIGNIFICANCE STATEMENT Gastric vagal afferent responses to tension are dampened in high fat diet-induced obesity. Endocannabinoids are known to dose-dependently inhibit and excite gastric vagal afferents but their effect on gastric vagal afferents in diet-induced obesity are unknown. In individual gastric vagal afferent neurons of diet-induced obese mice the co-expression of components of the endocannabinoid system, including CB1, GHSR, TRPV1 and FAAH, was increased compared with lean mice. In high fat diet-induced obese mice, methanandamide only inhibited gastric vagal afferent responses to tension, possibly due to the observed change in the balance of receptors, hormones and breakdown enzymes in this system. Collectively, these data suggest that endocannabinoid signalling, by gastric vagal afferents, is altered in diet-induced obesity which may impact satiety and gastrointestinal function. ABSTRACT Gastric vagal afferents (GVAs) play a role in appetite regulation. The endocannabinoid anandamide (AEA) dose-dependently inhibits and excites tension-sensitive GVAs. However, it is also known that high fat diet (HFD) feeding alters GVA responses to stretch. The aim of this study was to determine the role of AEA in GVA signalling in lean and HFD-induced obese mice. Male C57BL/6 mice were fed (12 weeks) a standard laboratory diet (SLD) or HFD. Protein and mRNA expression of components of the cannabinoid system was determined in individual GVA cell bodies and the gastric mucosa. An in vitro GVA preparation was used to assess the effect of methanandamide (mAEA) on tension-sensitive GVAs and the second messenger pathways involved. In individual GVA cell bodies, cannabinoid 1 (CB1) and ghrelin (GHSR) receptor mRNA was higher in HFD mice than SLD mice. Conversely, gastric mucosal AEA and ghrelin protein levels were lower in HFD mice than SLD mice. In SLD mice, mAEA exerted dose-dependent inhibitory and excitatory effects on tension-sensitive GVAs. Only an inhibitory effect of mAEA was observed in HFD mice. The excitatory effect of mAEA was dependent on CB1, transient receptor potential vanilloid 1 (TRPV1) and the protein kinase C. Conversely, the inhibitory effect was dependent on CB1, growth hormone secretagogue receptor, TRPV1 and the protein kinase A. Endocannabinoids, acting through CB1 and TRPV1, have a pivotal role in modulating GVA satiety signals depending on the second messenger pathway utilised. In HFD mice only an inhibitory effect was observed. These changes may contribute to the development and/or maintenance of obesity.
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Affiliation(s)
- Stewart Christie
- Vagal Afferent Research Group, Adelaide Medical School, University of Adelaide, Adelaide, SA, 5005, Australia
| | - Rebecca O'Rielly
- Vagal Afferent Research Group, Adelaide Medical School, University of Adelaide, Adelaide, SA, 5005, Australia
| | - Hui Li
- Vagal Afferent Research Group, Adelaide Medical School, University of Adelaide, Adelaide, SA, 5005, Australia.,Nutrition, Diabetes & Gut Health, Lifelong Health Theme, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA, 5000, Australia
| | - Maria Nunez-Salces
- Vagal Afferent Research Group, Adelaide Medical School, University of Adelaide, Adelaide, SA, 5005, Australia
| | - Gary A Wittert
- Vagal Afferent Research Group, Adelaide Medical School, University of Adelaide, Adelaide, SA, 5005, Australia.,Nutrition, Diabetes & Gut Health, Lifelong Health Theme, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA, 5000, Australia
| | - Amanda J Page
- Vagal Afferent Research Group, Adelaide Medical School, University of Adelaide, Adelaide, SA, 5005, Australia.,Nutrition, Diabetes & Gut Health, Lifelong Health Theme, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA, 5000, Australia
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11
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Razolli DS, de Araújo TM, Sant Apos Ana MR, Kirwan P, Cintra DE, Merkle FT, Velloso LA. Proopiomelanocortin Processing in the Hypothalamus Is Directly Regulated by Saturated Fat: Implications for the Development of Obesity. Neuroendocrinology 2020; 110:92-104. [PMID: 31104058 PMCID: PMC7614303 DOI: 10.1159/000501023] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 05/17/2019] [Indexed: 02/02/2023]
Abstract
In outbred mice, susceptibility or resistance to diet-induced obesity is associated with rapid changes in hypothalamic proopiomelanocortin (POMC) levels. Here, we evaluated 3 hypotheses that potentially explain the development of the different obesity phenotypes in outbred Swiss mice. First, rapid and differential changes in the gut microbiota in obesity-prone (OP) and obesity-resistant (OR) mice fed on a high-fat diet (HFD) might cause differential efficiencies in fatty acid harvesting leading to changes in systemic fatty acid concentrations that in turn affect POMC expression and processing. Second, independently of the gut microbiota, OP mice might have increased blood fatty acid levels after the introduction of a HFD, which could affect POMC expression and processing. Third, fatty acids might act directly in the hypothalamus to differentially regulate POMC expression and/or processing in OP and OR mice. We evaluated OP and OR male Swiss mice using 16S rRNA sequencing for the determination of gut microbiota; gas chromatography for blood lipid determination; and immunoblot and real-time polymerase chain reaction for protein and transcript determination and indirect calorimetry. Some experiments were performed with human pluripotent stem cells differentiated into hypothalamic neurons. We did not find evidence supporting the first 2 hypotheses. However, we found that in OP but not in OR mice, palmitate induces a rapid increase in hypothalamic POMC, which is followed by increased expression of proprotein convertase subtilisin/kexin type 1 PC1/3. Lentiviral inhibition of hypothalamic PC1/3 increased caloric intake and body mass in both OP and OR mice. In human stem cell-derived hypothalamic cells, we found that palmitate potently suppressed the production of POMC-derived peptides. Palmitate directly regulates PC1/3 in OP mice and likely has a functional impact on POMC processing.
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Affiliation(s)
- Daniela S Razolli
- Laboratory of Cell Signalling-Obesity and Comorbidities Research Center, University of Campinas, Campinas, Brazil
| | - Thiago M de Araújo
- Laboratory of Cell Signalling-Obesity and Comorbidities Research Center, University of Campinas, Campinas, Brazil
| | - Marcella R Sant Apos Ana
- Laboratory of Nutritional Genomics, School of Applied Science, University of Campinas, Limeira, Brazil
| | - Peter Kirwan
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust, Medical Research Council Institute of Metabolic Science, and Wellcome Trust Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge, United Kingdom
| | - Dennys E Cintra
- Laboratory of Nutritional Genomics, School of Applied Science, University of Campinas, Limeira, Brazil
| | - Florian T Merkle
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust, Medical Research Council Institute of Metabolic Science, and Wellcome Trust Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge, United Kingdom
| | - Licio A Velloso
- Laboratory of Cell Signalling-Obesity and Comorbidities Research Center, University of Campinas, Campinas, Brazil,
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12
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aPKC in neuronal differentiation, maturation and function. Neuronal Signal 2019; 3:NS20190019. [PMID: 32269838 PMCID: PMC7104321 DOI: 10.1042/ns20190019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 09/10/2019] [Accepted: 09/11/2019] [Indexed: 12/17/2022] Open
Abstract
The atypical Protein Kinase Cs (aPKCs)—PRKCI, PRKCZ and PKMζ—form a subfamily within the Protein Kinase C (PKC) family. These kinases are expressed in the nervous system, including during its development and in adulthood. One of the aPKCs, PKMζ, appears to be restricted to the nervous system. aPKCs are known to play a role in a variety of cellular responses such as proliferation, differentiation, polarity, migration, survival and key metabolic functions such as glucose uptake, that are critical for nervous system development and function. Therefore, these kinases have garnered a lot of interest in terms of their functional role in the nervous system. Here we review the expression and function of aPKCs in neural development and in neuronal maturation and function. Despite seemingly paradoxical findings with genetic deletion versus gene silencing approaches, we posit that aPKCs are likely candidates for regulating many important neurodevelopmental and neuronal functions, and may be associated with a number of human neuropsychiatric diseases.
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13
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Ganglioside deficiency in hypothalamic POMC neurons promotes body weight gain. Int J Obes (Lond) 2019; 44:510-524. [PMID: 31168055 DOI: 10.1038/s41366-019-0388-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 03/15/2019] [Accepted: 04/05/2019] [Indexed: 11/09/2022]
Abstract
BACKGROUND Glucosylceramide synthase (GCS; gene: UDP-glucose:ceramide glucosyltransferase (Ugcg))-derived gangliosides comprise a specific class of lipids in the plasma membrane that modulate the activity of transmembrane receptors. GCS deletion in hypothalamic arcuate nucleus (Arc) neurons leads to prominent obesity. However, it has not yet been studied how ganglioside depletion affects individual Arc neuronal subpopulations. The current study investigates the effects of GCS deletion specifically in anorexigenic pro-opiomelanocortin (POMC) neurons. Additionally, we investigate insulin receptor (IR) signaling and phosphatidylinositol-(3,4,5)-trisphosphate (PIP3) binding to ATP-dependent K+ (KATP) channels of GCS-deficient POMC neurons. MATERIALS AND METHODS We generated Ugcgf/f-Pomc-Cre mice with ganglioside deficiency in POMC neurons. Moreover, the CRISPR (clustered regulatory interspaced short palindromic repeats)/Cas9 technology was used to inhibit GCS-dependent ganglioside biosynthesis in cultured mouse POMC neurons, yielding UgcgΔ-mHypoA-POMC cells that were used to study mechanistic aspects in further detail. Proximity ligation assays (PLAs) visualized interactions between gangliosides, IR, and KATP channel subunit sulfonylurea receptor-1 (SUR-1), as well as intracellular IR substrate 2 (IRS-2) phosphorylation and PIP3. RESULTS Chow-fed Ugcgf/f-Pomc-Cre mice showed a moderate but significant increase in body weight gain and they failed to display an increase of anorexigenic neuropeptide expression during the fasting-to-re-feeding transition. IR, IRS-2, p85, and overall insulin-evoked IR and IRS-2 phosphorylation were elevated in ganglioside-depleted UgcgΔ-mHypoA-POMC neurons. A PLA demonstrated that more insulin-evoked complex formation occurred between PIP3 and SUR-1 in ganglioside-deficient POMC neurons in vitro and in vivo. CONCLUSION Our work suggests that GCS deletion in POMC neurons promotes body weight gain. Gangliosides are required for an appropriate adaptation of anorexigenic neuropeptide expression in the Arc during the fasting-to-re-feeding transition. Moreover, gangliosides might modulate KATP channel activity by restraining PIP3 binding to the KATP channel subunit SUR-1. Increased PIP3/SUR-1 interactions in ganglioside-deficient neurons could in turn potentially lead to electrical silencing. This work highlights that gangliosides in POMC neurons of the hypothalamic Arc are important regulators of body weight.
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14
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Baldini G, Phelan KD. The melanocortin pathway and control of appetite-progress and therapeutic implications. J Endocrinol 2019; 241:R1-R33. [PMID: 30812013 PMCID: PMC6500576 DOI: 10.1530/joe-18-0596] [Citation(s) in RCA: 125] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 01/22/2019] [Indexed: 12/19/2022]
Abstract
The initial discovery that ob/ob mice become obese because of a recessive mutation of the leptin gene has been crucial to discover the melanocortin pathway to control appetite. In the melanocortin pathway, the fed state is signaled by abundance of circulating hormones such as leptin and insulin, which bind to receptors expressed at the surface of pro-opiomelanocortin (POMC) neurons to promote processing of POMC to the mature hormone α-melanocyte-stimulating hormone (α-MSH). The α-MSH released by POMC neurons then signals to decrease energy intake by binding to melanocortin-4 receptor (MC4R) expressed by MC4R neurons to the paraventricular nucleus (PVN). Conversely, in the 'starved state' activity of agouti-related neuropeptide (AgRP) and of neuropeptide Y (NPY)-expressing neurons is increased by decreased levels of circulating leptin and insulin and by the orexigenic hormone ghrelin to promote food intake. This initial understanding of the melanocortin pathway has recently been implemented by the description of the complex neuronal circuit that controls the activity of POMC, AgRP/NPY and MC4R neurons and downstream signaling by these neurons. This review summarizes the progress done on the melanocortin pathway and describes how obesity alters this pathway to disrupt energy homeostasis. We also describe progress on how leptin and insulin receptors signal in POMC neurons, how MC4R signals and how altered expression and traffic of MC4R change the acute signaling and desensitization properties of the receptor. We also describe how the discovery of the melanocortin pathway has led to the use of melanocortin agonists to treat obesity derived from genetic disorders.
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Affiliation(s)
- Giulia Baldini
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Kevin D. Phelan
- Department of Neurobiology & Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
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15
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Li X, Xu L, Hou X, Geng J, Tian J, Liu X, Bai X. Advanced Oxidation Protein Products Aggravate Tubulointerstitial Fibrosis Through Protein Kinase C-Dependent Mitochondrial Injury in Early Diabetic Nephropathy. Antioxid Redox Signal 2019; 30:1162-1185. [PMID: 29482336 DOI: 10.1089/ars.2017.7208] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
AIMS Diabetic nephropathy (DN) is the most common microvascular complications and the principal cause of mortality and morbidity rates in patients with diabetes. The expression of advanced oxidation protein products (AOPPs) has been found in vacuolated renal tubules in DN and correlated with patients' decreased renal function. The accumulation of AOPPs is regarded as an initiating factor in podocyte injuries via the protein kinase C (PKC) signaling, which plays a critical role in triggering oxidative stress and mitochondrial injuries in diseases including DN. Whether AOPPs could induce mitochondrial injuries and fibrosis in renal tubules remains largely unknown. Herein, we tested the hypothesis that the accumulation of AOPPs in diabetes incurs mitochondrial dysfunction and oxidative stress, causing renal tubulointerstitial fibrosis (TIF) via PKC signaling pathway. RESULTS In vivo, intrarenal AOPPs accumulation correlated with oxidative stress, renal fibrosis, proteinuria, and declined renal function in DN patients and diabetic rats. AOPPs-induced mitochondrial injuries, apoptosis, and TIF were significantly mitigated by PKCη inhibition in diabetic rats. In vitro, high glucose (HG) stimulated AOPP expression and augmented PKC-mediated oxidative stress and fibrosis in HK-2 cells. Furthermore, we provide mechanistic evidence that inhibition of PKCη isoform alleviated mitochondrial injuries and function, attenuated apoptosis, and renal fibrosis in HG-cultured AOPPs-induced HK-2 cells. Innovation and Conclusion: We propose a novel mechanism that AOPPs-induced mitochondrial dysfunction and oxidative stress cause TIF in DN via activation of the PKCη isoform.
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Affiliation(s)
- Xiao Li
- 1 Department of Emergency, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, People's Republic of China
| | - Liting Xu
- 2 Division of Nephrology, Nanfang Hospital, Southern Medical University, National Clinical Research Center for Kidney Disease, State Key Laboratory of Organ Failure Research, Guangdong Provincial Institute of Nephrology, Guangzhou, Guangdong, People's Republic of China
| | - Xiaoyan Hou
- 3 Department of Nephrology, The First Affiliated Hospital, Inner Mongolia Medical University, Hohhot, Inner Mongolia, People's Republic of China
| | - Jian Geng
- 4 Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, People's Republic of China
| | - Jianwei Tian
- 2 Division of Nephrology, Nanfang Hospital, Southern Medical University, National Clinical Research Center for Kidney Disease, State Key Laboratory of Organ Failure Research, Guangdong Provincial Institute of Nephrology, Guangzhou, Guangdong, People's Republic of China
| | - Xiaoting Liu
- 5 Department of Pathology, King Medical Diagnostics Center, Guangzhou, Guangdong, People's Republic of China
| | - Xiaoyan Bai
- 2 Division of Nephrology, Nanfang Hospital, Southern Medical University, National Clinical Research Center for Kidney Disease, State Key Laboratory of Organ Failure Research, Guangdong Provincial Institute of Nephrology, Guangzhou, Guangdong, People's Republic of China
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16
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Gilloteaux J, Subramanian K, Solomon N, Nicaise C. The leptin receptor mutation of the obese Zucker rat causes sciatic nerve demyelination with a centripetal pattern defect. Ultrastruct Pathol 2018; 42:377-408. [PMID: 30339059 DOI: 10.1080/01913123.2018.1522405] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Young male Zucker rats with a leptin receptor mutation are obese, have a non-insulin-dependent diabetes mellitus (NIDDM), and other endocrinopathies. Tibial branches of the sciatic nerve reveal a progressive demyelination that progresses out of the Schwann cells (SCs) where electron-contrast deposits are accumulated while the minor lines or intermembranous SC contacts display exaggerated spacings. Cajal bands contain diversely contrasted vesicles adjacent to the abaxonal myelin layer with blemishes; they appear dispatched centripetally out of many narrow electron densities, regularly spaced around the myelin annulus. These anomalies widen and yield into sectors across the stacked myelin layers. Throughout the worse degradations, the adaxonal membrane remains along the axonal neuroplasm. This peripheral neuropathy with irresponsive leptin cannot modulate hypothalamic-pituitary-adrenal axis and SC neurosteroids, thus exacerbates NIDDM condition. Additionally, the ultrastructure of the progressive myelin alterations may have unraveled a peculiar, centripetal mode of trafficking maintenance of the peripheral nervous system myelin, while some adhesive glycoproteins remain between myelin layers, somewhat hindering the axon mutilation. Heading title: Peripheral neuropathy and myelin.
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Affiliation(s)
- Jacques Gilloteaux
- a Department of Anatomical Sciences , St George's University School of Medicine, K.B. Taylor Global Scholar's Program at Northumbria University , Newcastle upon Tyne , UK.,b Unité de Recherche en Physiologie Moléculaire (URPhyM), Laboratoire de Neurodégénérescence et Régénération, Département de Médecine , Université de Namur , Namur , Belgium
| | - Kritika Subramanian
- a Department of Anatomical Sciences , St George's University School of Medicine, K.B. Taylor Global Scholar's Program at Northumbria University , Newcastle upon Tyne , UK.,c Department of Clinical and Epidemiological Virology , Rega Institute of Medical Research, Katholiele Universiteit Leuven , Leuven , Belgium
| | - Nadia Solomon
- a Department of Anatomical Sciences , St George's University School of Medicine, K.B. Taylor Global Scholar's Program at Northumbria University , Newcastle upon Tyne , UK
| | - Charles Nicaise
- b Unité de Recherche en Physiologie Moléculaire (URPhyM), Laboratoire de Neurodégénérescence et Régénération, Département de Médecine , Université de Namur , Namur , Belgium
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17
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Pharmacological Inhibition of Protein Kinase C Reduces West Nile Virus Replication. Viruses 2018; 10:v10020091. [PMID: 29473907 PMCID: PMC5850398 DOI: 10.3390/v10020091] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 02/13/2018] [Accepted: 02/22/2018] [Indexed: 12/14/2022] Open
Abstract
Flaviviruses are relevant animal and human pathogens that include West Nile virus (WNV), Japanese encephalitis virus, dengue virus, or Zika virus, among others. Currently, no licensed therapy is available to fight flaviviral infections. Protein kinases C (PKCs) constitute a family of multifunctional lipid-dependent isoenzymes that regulate a wide variety of cellular processes (apoptosis, differentiation, proliferation, cellular transformation, motility, adhesion, etc.) being currently considered at the front line of drug development for the treatment of diverse human disorders. PKCs have also been implicated in different steps during viral replication; however, nowadays, results regarding their role in flavivirus replication are controversial. Here we demonstrate that calphostin C and chelerythrine, two broad-PKC inhibitors that target conventional, novel and atypical PKCs, significantly inhibit WNV multiplication in cell culture without affecting cell viability. A reduction of viral yields was observed in treated cells when compared with mock-treated cells. Likewise, immunofluorescence detection of viral enveloped E protein was reduced in treated cells, as was the amount of viral RNA released to the supernatant, mainly in those treated with chelerythrine. On the other hand, two PKC inhibitors specific for conventional and novel isoforms (staurosporine and enzastaurine) did not show any significant effect in WNV multiplication. These results suggested that PKCs, more probably atypical PKCs, are likely involved in WNV multiplication, although both broad-spectrum tested drugs seem to act through different mechanisms, and point to them as potential antiviral candidates for WNV, as well as for other related flaviviruses.
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