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Song WJ, Cheon DH, Song H, Jung D, Chan Park H, Yeong Hwang J, Choi HJ, NamKoong C. Activation of ChAT+ neuron in dorsal motor vagus (DMV) increases blood glucose through the regulation of hepatic gene expression in mice. Brain Res 2024; 1829:148770. [PMID: 38266888 DOI: 10.1016/j.brainres.2024.148770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 01/10/2024] [Accepted: 01/13/2024] [Indexed: 01/26/2024]
Abstract
The brain and peripheral organs communicate through hormones and neural connections. Proper communication is required to maintain normal whole-body energy homeostasis. In addition to endocrine system, from the perspective of neural connections for metabolic homeostasis, the role of the sympathetic nervous system has been extensively studied, but understanding of the parasympathetic nervous system is limited. The liver plays a central role in glucose and lipid metabolism. This study aimed to clarify the innervation of parasympathetic nervous system in the liver and its functional roles in metabolic homeostasis. The liver-specific parasympathetic nervous system innervation (PNS) was shown by tissue clearing, immunofluorescence and transgenic mice at the three-dimensional histological level. The parasympathetic efferent signals were manipulated using a chemogenetic technique and the activation of ChAT+ parasympathetic neurons in dorsal motor vagus (DMV) results in the increased blood glucose through the elevated hepatic gluconeogenic and lipogenic gene expression in the liver. Thus, our study showed the evidence of ChAT+ parasympathetic neurons in the liver and its role for hepatic parasympathetic nervous signaling in glucose homeostasis through the regulation of hepatic gene expression.
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Affiliation(s)
- Woo-Jin Song
- Functional Neuroanatomy of Metabolism Regulation Laboratory, Department of Anatomy, Division of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea; Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Deok-Hyeon Cheon
- Functional Neuroanatomy of Metabolism Regulation Laboratory, Department of Anatomy, Division of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea; Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - HeeIn Song
- Functional Neuroanatomy of Metabolism Regulation Laboratory, Department of Anatomy, Division of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Daeun Jung
- Functional Neuroanatomy of Metabolism Regulation Laboratory, Department of Anatomy, Division of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Hae Chan Park
- Functional Neuroanatomy of Metabolism Regulation Laboratory, Department of Anatomy, Division of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Ju Yeong Hwang
- Functional Neuroanatomy of Metabolism Regulation Laboratory, Department of Anatomy, Division of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Hyung-Jin Choi
- Functional Neuroanatomy of Metabolism Regulation Laboratory, Department of Anatomy, Division of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea; Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea; BK21Plus Biomedical Science Project Team, Seoul National University College of Medicine, Seoul, Republic of Korea; Wide River Institute of Immunology, Seoul National University College of Medicine, Hongchoen, Republic of Korea; Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.
| | - Cherl NamKoong
- Functional Neuroanatomy of Metabolism Regulation Laboratory, Department of Anatomy, Division of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea; Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea; Core Research Laboratory, Medical Science Institute, Kyung Hee University Hospital at Gangdong, Seoul 05278, Republic of Korea.
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Kim HR, Young CN. Circumventricular organ-hypothalamic circuit endoplasmic reticulum stress drives hepatic steatosis during obesity. Obesity (Silver Spring) 2024; 32:59-69. [PMID: 37794528 DOI: 10.1002/oby.23895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 08/08/2023] [Accepted: 08/08/2023] [Indexed: 10/06/2023]
Abstract
OBJECTIVE Nonalcoholic fatty liver disease (NAFLD), characterized by excess liver triglyceride accumulation (hepatic steatosis), leads to an increased risk for cardiometabolic diseases and obesity-related mortality. Emerging evidence points to endoplasmic reticulum (ER) stress in the central nervous system as critical in NAFLD pathogenesis. Here, we tested the contribution of ER stress in a circumventricular organ-hypothalamic circuit in NAFLD development during obesity. METHODS C57BL/6J male mice were fed a high-fat diet (HFD) or normal chow. A combination of histological, viral tracing, intersectional viral targeting, and in vivo integrative physiological approaches were used to examine the role of ER stress in subfornical organ to hypothalamic paraventricular nucleus projecting neurons (SFO➔PVN) in NAFLD during diet-induced obesity. RESULTS Immunohistochemical analysis revealed marked unfolded protein response activation in the SFO, particularly in excitatory SFO➔PVN neurons of HFD-fed animals. Moreover, intersectional viral inhibition of ER stress in SFO➔PVN neurons resulted in a reduction in hepatomegaly, hepatic steatosis, and a blunted increase in body weight gain during diet-induced obesity, independent of changes in food intake, substrate partitioning, energy expenditure, and ambulatory activity. CONCLUSIONS These results indicate that ER stress in an SFO➔PVN neural circuit contributes to hepatic steatosis during obesity.
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Affiliation(s)
- Han Rae Kim
- Department of Pharmacology and Physiology, George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - Colin N Young
- Department of Pharmacology and Physiology, George Washington University School of Medicine and Health Sciences, Washington, DC, USA
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Zsombok A, Desmoulins LD, Derbenev AV. Sympathetic circuits regulating hepatic glucose metabolism: where we stand. Physiol Rev 2024; 104:85-101. [PMID: 37440208 DOI: 10.1152/physrev.00005.2023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 06/12/2023] [Accepted: 07/10/2023] [Indexed: 07/14/2023] Open
Abstract
The prevalence of metabolic disorders, including type 2 diabetes mellitus, continues to increase worldwide. Although newer and more advanced therapies are available, current treatments are still inadequate and the search for solutions remains. The regulation of energy homeostasis, including glucose metabolism, involves an exchange of information between the nervous systems and peripheral organs and tissues; therefore, developing treatments to alter central and/or peripheral neural pathways could be an alternative solution to modulate whole body metabolism. Liver glucose production and storage are major mechanisms controlling glycemia, and the autonomic nervous system plays an important role in the regulation of hepatic functions. Autonomic nervous system imbalance contributes to excessive hepatic glucose production and thus to the development and progression of type 2 diabetes mellitus. At cellular levels, change in neuronal activity is one of the underlying mechanisms of autonomic imbalance; therefore, modulation of the excitability of neurons involved in autonomic outflow governance has the potential to improve glycemic status. Tissue-specific subsets of preautonomic neurons differentially control autonomic outflow; therefore, detailed information about neural circuits and properties of liver-related neurons is necessary for the development of strategies to regulate liver functions via the autonomic nerves. This review provides an overview of our current understanding of the hypothalamus-ventral brainstem-liver pathway involved in the sympathetic regulation of the liver, outlines strategies to identify organ-related neurons, and summarizes neuronal plasticity during diabetic conditions with a particular focus on liver-related neurons in the paraventricular nucleus.
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Affiliation(s)
- Andrea Zsombok
- Department of Physiology, School of Medicine, Tulane University, New Orleans, Louisiana, United States
- Tulane Brain Institute, Tulane University, New Orleans, Louisiana, United States
| | - Lucie D Desmoulins
- Department of Physiology, School of Medicine, Tulane University, New Orleans, Louisiana, United States
| | - Andrei V Derbenev
- Department of Physiology, School of Medicine, Tulane University, New Orleans, Louisiana, United States
- Tulane Brain Institute, Tulane University, New Orleans, Louisiana, United States
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