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Kuo HCN, LaRussa Z, Xu FM, West K, Consitt L, Davidson WS, Liu M, Coschigano KT, Shi H, Lo CC. Apolipoprotein A4 Elevates Sympathetic Activity and Thermogenesis in Male Mice. Nutrients 2023; 15:2486. [PMID: 37299447 PMCID: PMC10255745 DOI: 10.3390/nu15112486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 05/22/2023] [Accepted: 05/25/2023] [Indexed: 06/12/2023] Open
Abstract
Long-chain fatty acids induce apolipoprotein A4 (APOA4) production in the small intestine and activate brown adipose tissue (BAT) thermogenesis. The increase in BAT thermogenesis enhances triglyceride clearance and insulin sensitivity. Acute administration of recombinant APOA4 protein elevates BAT thermogenesis in chow-fed mice. However, the physiological role of continuous infusion of recombinant APOA4 protein in regulating sympathetic activity, thermogenesis, and lipid and glucose metabolism in low-fat-diet (LFD)-fed mice remained elusive. The hypothesis of this study was that continuous infusion of mouse APOA4 protein would increase sympathetic activity and thermogenesis in BAT and subcutaneous inguinal white adipose tissue (IWAT), attenuate plasma lipid levels, and improve glucose tolerance. To test this hypothesis, sympathetic activity, BAT temperature, energy expenditure, body weight, fat mass, caloric intake, glucose tolerance, and levels of BAT and IWAT thermogenic and lipolytic proteins, plasma lipids, and markers of fatty acid oxidation in the liver in mice with APOA4 or saline treatment were measured. Plasma APOA4 levels were elevated, BAT temperature and thermogenesis were upregulated, and plasma triglyceride (TG) levels were reduced, while body weight, fat mass, caloric intake, energy expenditure, and plasma cholesterol and leptin levels were comparable between APOA4- and saline-treated mice. Additionally, APOA4 infusion stimulated sympathetic activity in BAT and liver but not in IWAT. APOA4-treated mice had greater fatty acid oxidation but less TG content in the liver than saline-treated mice had. Plasma insulin in APOA4-treated mice was lower than that in saline-treated mice after a glucose challenge. In conclusion, continuous infusion of mouse APOA4 protein stimulated sympathetic activity in BAT and the liver, elevated BAT thermogenesis and hepatic fatty acid oxidation, and consequently attenuated levels of plasma and hepatic TG and plasma insulin without altering caloric intake, body weight gain and fat mass.
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Affiliation(s)
- Hsuan-Chih N. Kuo
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine and Diabetes Institute, Ohio University, Athens, OH 45701, USA; (H.-C.N.K.); (Z.L.); (K.W.); (L.C.); (K.T.C.)
- Department of Biological Sciences, Ohio University, Athens, OH 45701, USA
| | - Zachary LaRussa
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine and Diabetes Institute, Ohio University, Athens, OH 45701, USA; (H.-C.N.K.); (Z.L.); (K.W.); (L.C.); (K.T.C.)
- Department of Biological Sciences, Ohio University, Athens, OH 45701, USA
| | - Flora Mengyang Xu
- Department of Biology, Miami University, Oxford, OH 45056, USA; (F.M.X.); (H.S.)
| | - Kathryn West
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine and Diabetes Institute, Ohio University, Athens, OH 45701, USA; (H.-C.N.K.); (Z.L.); (K.W.); (L.C.); (K.T.C.)
| | - Leslie Consitt
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine and Diabetes Institute, Ohio University, Athens, OH 45701, USA; (H.-C.N.K.); (Z.L.); (K.W.); (L.C.); (K.T.C.)
| | - William Sean Davidson
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH 45237, USA; (W.S.D.); (M.L.)
| | - Min Liu
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH 45237, USA; (W.S.D.); (M.L.)
| | - Karen T. Coschigano
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine and Diabetes Institute, Ohio University, Athens, OH 45701, USA; (H.-C.N.K.); (Z.L.); (K.W.); (L.C.); (K.T.C.)
| | - Haifei Shi
- Department of Biology, Miami University, Oxford, OH 45056, USA; (F.M.X.); (H.S.)
| | - Chunmin C. Lo
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine and Diabetes Institute, Ohio University, Athens, OH 45701, USA; (H.-C.N.K.); (Z.L.); (K.W.); (L.C.); (K.T.C.)
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LaRussa Z, Kuo HCN, West K, Shen Z, Wisniewski K, Tso P, Coschigano KT, Lo CC. Increased BAT Thermogenesis in Male Mouse Apolipoprotein A4 Transgenic Mice. Int J Mol Sci 2023; 24:4231. [PMID: 36835642 PMCID: PMC9959433 DOI: 10.3390/ijms24044231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 02/15/2023] [Accepted: 02/15/2023] [Indexed: 02/23/2023] Open
Abstract
Dietary lipids induce apolipoprotein A4 (APOA4) production and brown adipose tissue (BAT) thermogenesis. Administration of exogenous APOA4 elevates BAT thermogenesis in chow-fed mice, but not high-fat diet (HFD)-fed mice. Chronic feeding of HFD attenuates plasma APOA4 production and BAT thermogenesis in wildtype (WT) mice. In light of these observations, we sought to determine whether steady production of APOA4 could keep BAT thermogenesis elevated, even in the presence of HFD consumption, with an aim toward eventual reduction of body weight, fat mass and plasma lipid levels. Transgenic mice with overexpression of mouse APOA4 in the small intestine (APOA4-Tg mice) produce greater plasma APOA4 than their WT controls, even when fed an atherogenic diet. Thus, we used these mice to investigate the correlation of levels of APOA4 and BAT thermogenesis during HFD consumption. The hypothesis of this study was that overexpression of mouse APOA4 in the small intestine and increased plasma APOA4 production would increase BAT thermogenesis and consequently reduce fat mass and plasma lipids of HFD-fed obese mice. To test this hypothesis, BAT thermogenic proteins, body weight, fat mass, caloric intake, and plasma lipids in male APOA4-Tg mice and WT mice fed either a chow diet or a HFD were measured. When fed a chow diet, APOA4 levels were elevated, plasma triglyceride (TG) levels were reduced, and BAT levels of UCP1 trended upward, while body weight, fat mass, caloric intake, and plasma lipids were comparable between APOA4-Tg and WT mice. After a four-week feeding of HFD, APOA4-Tg mice maintained elevated plasma APOA4 and reduced plasma TG, but UCP1 levels in BAT were significantly elevated in comparison to WT controls; body weight, fat mass and caloric intake were still comparable. After 10-week consumption of HFD, however, while APOA4-Tg mice still exhibited increased plasma APOA4, UCP1 levels and reduced TG levels, a reduction in body weight, fat mass and levels of plasma lipids and leptin were finally observed in comparison to their WT controls and independent of caloric intake. Additionally, APOA4-Tg mice exhibited increased energy expenditure at several time points when measured during the 10-week HFD feeding. Thus, overexpression of APOA4 in the small intestine and maintenance of elevated levels of plasma APOA4 appear to correlate with elevation of UCP1-dependent BAT thermogenesis and subsequent protection against HFD-induced obesity in mice.
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Affiliation(s)
- Zachary LaRussa
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, and Diabetes Institute, Ohio University, Athens, OH 45701, USA
| | - Hsuan-Chih N Kuo
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, and Diabetes Institute, Ohio University, Athens, OH 45701, USA
| | - Kathryn West
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, and Diabetes Institute, Ohio University, Athens, OH 45701, USA
| | - Zhijun Shen
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, and Diabetes Institute, Ohio University, Athens, OH 45701, USA
| | - Kevin Wisniewski
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, and Diabetes Institute, Ohio University, Athens, OH 45701, USA
| | - Patrick Tso
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH 45237, USA
| | - Karen T Coschigano
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, and Diabetes Institute, Ohio University, Athens, OH 45701, USA
| | - Chunmin C Lo
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, and Diabetes Institute, Ohio University, Athens, OH 45701, USA
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Cawthon CR, de La Serre CB. The critical role of CCK in the regulation of food intake and diet-induced obesity. Peptides 2021; 138:170492. [PMID: 33422646 DOI: 10.1016/j.peptides.2020.170492] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 12/16/2020] [Accepted: 12/23/2020] [Indexed: 12/17/2022]
Abstract
In 1973, Gibbs, Young, and Smith showed that exogenous cholecystokinin (CCK) administration reduces food intake in rats. This initial report has led to thousands of studies investigating the physiological role of CCK in regulating feeding behavior. CCK is released from enteroendocrine I cells present along the gastrointestinal (GI) tract. CCK binding to its receptor CCK1R leads to vagal afferent activation providing post-ingestive feedback to the hindbrain. Vagal afferent neurons' (VAN) sensitivity to CCK is modulated by energy status while CCK signaling regulates gene expression of other feeding related signals and receptors expressed by VAN. In addition to its satiation effects, CCK acts all along the GI tract to optimize digestion and nutrient absorption. Diet-induced obesity (DIO) is characterized by reduced sensitivity to CCK and every part of the CCK system is negatively affected by chronic intake of energy-dense foods. EEC have recently been shown to adapt to diet, CCK1R is affected by dietary fats consumption, and the VAN phenotypic flexibility is lost in DIO. Altered endocannabinoid tone, changes in gut microbiota composition, and chronic inflammation are currently being explored as potential mechanisms for diet driven loss in CCK signaling. This review discusses our current understanding of how CCK controls food intake in conditions of leanness and how control is lost in chronic energy excess and obesity, potentially perpetuating excessive intake.
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Affiliation(s)
- Carolina R Cawthon
- Department of Foods and Nutrition, University of Georgia, Athens, GA, USA
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4
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Central Apolipoprotein A-IV Stimulates Thermogenesis in Brown Adipose Tissue. Int J Mol Sci 2021; 22:ijms22031221. [PMID: 33513710 PMCID: PMC7865537 DOI: 10.3390/ijms22031221] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 01/22/2021] [Indexed: 12/30/2022] Open
Abstract
Stimulation of thermogenesis in brown adipose tissue (BAT) could have far-reaching health benefits in combatting obesity and obesity-related complications. Apolipoprotein A-IV (ApoA-IV), produced by the gut and the brain in the presence of dietary lipids, is a well-known short-term satiating protein. While our previous studies have demonstrated reduced diet-induced thermogenesis in ApoA-IV-deficient mice, it is unclear whether this reduction is due to a loss of peripheral or central effects of ApoA-IV. We hypothesized that central administration of ApoA-IV stimulates BAT thermogenesis and that sympathetic and sensory innervation is necessary for this action. To test this hypothesis, mice with unilateral denervation of interscapular BAT received central injections of recombinant ApoA-IV protein or artificial cerebrospinal fluid (CSF). The effects of central ApoA-IV on BAT temperature and thermogenesis in mice with unilateral denervation of the intrascapular BAT were monitored using transponder probe implantation, qPCR, and immunoblots. Relative to CSF, central administration of ApoA-IV significantly increased temperature and UCP expression in BAT. However, all of these effects were significantly attenuated or prevented in mice with unilateral denervation. Together, these results clearly demonstrate that ApoA-IV regulates BAT thermogenesis centrally, and this effect is mediated through sympathetic and sensory nerves.
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Li Y, Cui ZJ. Photodynamic Activation of Cholecystokinin 1 Receptor with Different Genetically Encoded Protein Photosensitizers and from Varied Subcellular Sites. Biomolecules 2020; 10:biom10101423. [PMID: 33050050 PMCID: PMC7601527 DOI: 10.3390/biom10101423] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 10/01/2020] [Accepted: 10/06/2020] [Indexed: 02/07/2023] Open
Abstract
Cholecystokinin 1 receptor (CCK1R) is activated by singlet oxygen (1O2) generated in photodynamic action with sulphonated aluminum phthalocyanine (SALPC) or genetically encoded protein photosensitizer (GEPP) KillerRed or mini singlet oxygen generator (miniSOG). A large number of GEPP with varied 1O2 quantum yields have appeared recently; therefore, in the present work, the efficacy of different GEPP to photodynamically activate CCK1R was examined, as monitored by Fura-2 calcium imaging. KillerRed, miniSOG, miniSOG2, singlet oxygen protein photosensitizer (SOPP), flavin-binding fluorescent protein from Methylobacterium radiotolerans with point mutation C71G (Mr4511C71G), and flavin-binding fluorescent protein from Dinoroseobacter shibae (DsFbFP) were expressed at the plasma membrane (PM) in AR4-2J cells, which express endogenous CCK1R. Light irradiation (KillerRed: white light 85.3 mW‧cm-2, 4' and all others: LED 450 nm, 85 mW·cm-2, 1.5') of GEPPPM-expressing AR4-2J was found to all trigger persistent calcium oscillations, a hallmark of permanent photodynamic CCK1R activation; DsFbFP was the least effective, due to poor expression. miniSOG was targeted to PM, mitochondria (MT) or lysosomes (LS) in AR4-2J in parallel experiments; LED light irradiation was found to all induce persistent calcium oscillations. In miniSOGPM-AR4-2J cells, light emitting diode (LED) light irradiation-induced calcium oscillations were readily inhibited by CCK1R antagonist devazepide 2 nM; miniSOGMT-AR4-2J cells were less susceptible, but miniSOGLS-AR4-2J cells were not inhibited. In conclusion, different GEPPPM could all photodynamically activate CCK1R. Intracellular GEPP photodynamic action may prove particularly suited to study intracellular GPCR.
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6
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Pence S, Zhu Q, Binne E, Liu M, Shi H, Lo CC. Reduced Diet-induced Thermogenesis in Apolipoprotein A-IV Deficient Mice. Int J Mol Sci 2019; 20:E3176. [PMID: 31261740 PMCID: PMC6651278 DOI: 10.3390/ijms20133176] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 06/21/2019] [Accepted: 06/25/2019] [Indexed: 12/14/2022] Open
Abstract
In the presence of dietary lipids, both apolipoprotein A-IV (ApoA-IV) production and brown adipose tissue (BAT) thermogenesis are increased. The effect of dietary lipid-induced AproA-IV on BAT thermogenesis and energy expenditure remains unknown. In the present study, we hypothesized that ApoA-IV knockout (ApoA-IV-KO) mice exhibited decreased BAT thermogenesis to affect energy homeostasis. To test this hypothesis, BAT thermogenesis in wildtype (WT) and ApoA-IV-KO mice fed either a standard low-fat chow diet or a high-fat diet (HFD) was investigated. When fed a chow diet, energy expenditure and food intake were comparable between WT and ApoA-IV-KO mice. After 1 week of HFD consumption, ApoA-IV-KO mice had comparable energy intake but produced lower energy expenditure relative to their WT controls in the dark phase. After an acute feeding of dietary lipids or 1-week HFD feeding, ApoA-IV-KO mice produced lower levels of uncoupling protein 1 (UCP1) and exhibited reduced expression of thermogenic genes in the BAT compared with WT controls. In response to cold exposure, however, ApoA-IV-KO mice had comparable energy expenditure and BAT temperature relative to WT mice. Thus, ApoA-IV-KO mice exhibited reduced diet-induced BAT thermogenesis and energy expenditure.
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Affiliation(s)
- Sydney Pence
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Diabetes Institute and Honor Tutorial College, Ohio University, Athens, OH 45701, USA
| | - Qi Zhu
- Department of Biology, Miami University, Oxford, OH 45056, USA
| | - Erin Binne
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Diabetes Institute and Honor Tutorial College, Ohio University, Athens, OH 45701, USA
| | - Min Liu
- Department of Pathology and Laboratory Medicine, Metabolic Diseases Institute, University of Cincinnati, Cincinnati, OH 45215, USA
| | - Haifei Shi
- Department of Biology, Miami University, Oxford, OH 45056, USA
| | - Chunmin C Lo
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Diabetes Institute and Honor Tutorial College, Ohio University, Athens, OH 45701, USA.
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Zhan J, Weng J, Hunt BG, Sean Davidson W, Liu M, Lo CC. Apolipoprotein A-IV enhances cholecystokinnin secretion. Physiol Behav 2018; 188:11-17. [PMID: 29378187 PMCID: PMC5845788 DOI: 10.1016/j.physbeh.2018.01.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 01/23/2018] [Accepted: 01/23/2018] [Indexed: 02/05/2023]
Abstract
Cholecystokinin (CCK) and apolipoprotein A-IV (ApoA-IV) are gastrointestinal peptides that play an important role in controlling energy homeostasis. Lymphatic ApoA-IV and plasma CCK secretion are mediated via a chylomicron formation-dependent pathway during a dietary lipid infusion. Given their similar roles as satiating proteins, the present study examines how the two peptides interact in their function. Specifically, this study sought to understand how ApoA-IV regulates CCK secretion. For this purpose, Cck gene expression in the small intestines of ApoA-IV knockout (ApoA-IV-KO) and wild-type (WT) mice were compared under an array of feeding conditions. When fed with a chow or high-fat diet (HFD), basal levels of Cck transcripts were significantly reduced in the duodenum of ApoA-IV-KO mice compared to WT mice. Furthermore, after an oral gavage of a lipid mixture, Cck gene expression in the duodenum was significantly reduced in ApoA-IV-KO mice relative to the change seen in WT mice. To determine the mechanism by which ApoA-IV modulates Cck gene expression, STC-1 cells were transfected with predesigned mouse lysophosphatidic acid receptor 5 (LPAR5) small interfering RNA (siRNA) to knockdown Lpar5 gene expression. In this in-vitro study, mouse recombinant ApoA-IV protein increased Cck gene expression in enteroendocrine STC-1 cells and stimulated CCK release from the STC-1 cells. However, the levels of CCK protein and Cck expression were attenuated when Lpar5 was knocked down in the STC-1 cells. Together these observations suggest that dietary lipid-induced ApoA-IV is associated with Cck synthesis in the duodenum and that ApoA-IV protein directly enhances CCK release through the activation of a LPAR5-dependent pathway.
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Affiliation(s)
- Jesse Zhan
- Department of Biomedical Sciences, Diabetes Institute, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, USA; Department of Pathology and Laboratory Medicine, Metabolic Diseases Institute, University of Cincinnati, Cincinnati, OH, USA
| | - Jonathan Weng
- Department of Biomedical Sciences, Diabetes Institute, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, USA; Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Brian G Hunt
- Department of Pathology and Laboratory Medicine, Metabolic Diseases Institute, University of Cincinnati, Cincinnati, OH, USA
| | - W Sean Davidson
- Department of Pathology and Laboratory Medicine, Metabolic Diseases Institute, University of Cincinnati, Cincinnati, OH, USA
| | - Min Liu
- Department of Pathology and Laboratory Medicine, Metabolic Diseases Institute, University of Cincinnati, Cincinnati, OH, USA
| | - Chunmin C Lo
- Department of Biomedical Sciences, Diabetes Institute, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, USA.
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Woods SC, May AA, Liu M, Tso P, Begg DP. Using the cerebrospinal fluid to understand ingestive behavior. Physiol Behav 2017; 178:172-178. [PMID: 27923718 PMCID: PMC5944842 DOI: 10.1016/j.physbeh.2016.11.037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 11/22/2016] [Accepted: 11/28/2016] [Indexed: 01/08/2023]
Abstract
The cerebrospinal fluid (CSF) offers a window into the workings of the brain and blood-brain barrier (BBB). Molecules that enter into the central nervous system (CNS) by passive diffusion or receptor-mediated transport through the choroid plexus often appear in the CSF prior to acting within the brain. Other molecules enter the CNS by passing through the BBB into the brain's interstitial fluid prior to appearing in the CSF. This pattern is also often observed for molecules synthesized by neurons or glia within the CNS. The CSF is therefore an important conduit for the entry and clearance of molecules into/from the CNS and thereby constitutes an important window onto brain activity and barrier function. Assessing the CSF basally, under experimental conditions, or in the context of challenges or metabolic diseases can provide powerful insights about brain function. Here, we review important findings made by our labs, as influenced by the late Randall Sakai, by interrogating the CSF.
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Affiliation(s)
- Stephen C Woods
- Department of Psychiatry and Behavioral Neuroscience, Metabolic Diseases Institute, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
| | - Aaron A May
- Department of Pathology and Molecular Medicine, Metabolic Diseases Institute, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Min Liu
- Department of Pathology and Molecular Medicine, Metabolic Diseases Institute, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Patrick Tso
- Department of Pathology and Molecular Medicine, Metabolic Diseases Institute, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Denovan P Begg
- School of Psychology, University of New South Wales, Sydney, NSW 2052, Australia
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Weng J, Lou D, Benoit SC, Coschigano N, Woods SC, Tso P, Lo CC. Energy homeostasis in apolipoprotein AIV and cholecystokinin-deficient mice. Am J Physiol Regul Integr Comp Physiol 2017; 313:R535-R548. [PMID: 28768657 DOI: 10.1152/ajpregu.00034.2017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 07/25/2017] [Accepted: 07/26/2017] [Indexed: 11/22/2022]
Abstract
Apolipoprotein AIV (ApoAIV) and cholecystokinin (CCK) are well-known satiating signals that are stimulated by fat consumption. Peripheral ApoAIV and CCK interact to prolong satiating signals. In the present study, we hypothesized that ApoAIV and CCK control energy homeostasis in response to high-fat diet feeding. To test this hypothesis, energy homeostasis in ApoAIV and CCK double knockout (ApoAIV/CCK-KO), ApoAIV knockout (ApoAIV-KO), and CCK knockout (CCK-KO) mice were monitored. When animals were maintained on a low-fat diet, ApoAIV/CCK-KO, ApoAIV-KO, and CCK-KO mice had comparable energy intake and expenditure, body weight, fat mass, fat absorption, and plasma parameters relative to the controls. In contrast, these KO mice exhibited impaired lipid transport to epididymal fat pads in response to intraduodenal infusion of dietary lipids. Furthermore, ApoAIV-KO mice had upregulated levels of CCK receptor 2 (CCK2R) in the small intestine while ApoAIV/CCK-KO mice had upregulated levels of CCK2R in the brown adipose tissue. After 20 wk of a high-fat diet, ApoAIV-KO and CCK-KO mice had comparable body weight and fat mass, as well as lower energy expenditure at some time points. However, ApoAIV/CCK-KO mice exhibited reduced body weight and adiposity relative to wild-type mice, despite having normal food intake. Furthermore, ApoAIV/CCK-KO mice displayed normal fat absorption and locomotor activity, as well as enhanced energy expenditure. These observations suggest that mice lacking ApoAIV and CCK have reduced body weight and adiposity, possibly due to impaired lipid transport and elevated energy expenditure.
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Affiliation(s)
- Jonathan Weng
- Department of Biomedical Sciences, Molecular and Cellular Biology Program, and Diabetes Institute, Ohio University, Athens, Ohio.,Department of Molecular Biology and Genetics, Cornell University, Ithaca, NewYork
| | - Danwen Lou
- Department of Pathology and Laboratory Medicine, Metabolic Diseases Institute, University of Cincinnati, Cincinnati, Ohio; and
| | - Stephen C Benoit
- Department of Psychiatry, Metabolic Diseases Institute, University of Cincinnati, Cincinnati, Ohio
| | - Natalie Coschigano
- Department of Biomedical Sciences, Molecular and Cellular Biology Program, and Diabetes Institute, Ohio University, Athens, Ohio
| | - Stephen C Woods
- Department of Psychiatry, Metabolic Diseases Institute, University of Cincinnati, Cincinnati, Ohio
| | - Patrick Tso
- Department of Pathology and Laboratory Medicine, Metabolic Diseases Institute, University of Cincinnati, Cincinnati, Ohio; and
| | - Chunmin C Lo
- Department of Biomedical Sciences, Molecular and Cellular Biology Program, and Diabetes Institute, Ohio University, Athens, Ohio;
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May AA, Liu M, Woods SC, Begg DP. CCK increases the transport of insulin into the brain. Physiol Behav 2016; 165:392-7. [PMID: 27570192 PMCID: PMC5028313 DOI: 10.1016/j.physbeh.2016.08.025] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 08/24/2016] [Accepted: 08/24/2016] [Indexed: 11/17/2022]
Abstract
Food intake occurs in bouts or meals, and numerous meal-generated signals have been identified that act to limit the size of ongoing meals. Hormones such as cholecystokinin (CCK) are secreted from the intestine as ingested food is being processed, and in addition to aiding the digestive process, they provide a signal to the brain that contributes to satiation, limiting the size of the meal. The potency of CCK to elicit satiation is enhanced by elevated levels of adiposity signals such as insulin. In the present experiments we asked whether CCK and insulin interact at the level of the blood-brain barrier (BBB). We first isolated rat brain capillary endothelial cells that comprise the BBB and found that they express the mRNA for both the CCK1R and the insulin receptor, providing a basis for a possible interaction. We then administered insulin intraperitoneally to another group of rats and 15min later administered CCK-8 intraperitoneally to half of those rats. After another 15min, CSF and blood samples were obtained and assayed for immunoreactive insulin. Plasma insulin was comparably elevated above baseline in both the CCK-8 and control groups, indicating that the CCK had no effect on circulating insulin levels given these parameters. In contrast, rats administered CCK had CSF-insulin levels that were more than twice as high as those of control rats. We conclude that circulating CCK greatly facilitates the transport of insulin into the brain, likely by acting directly at the BBB. These findings imply that in circumstances in which the plasma levels of both CCK and insulin are elevated, such as during and soon after meals, satiation is likely to be due, in part, to this newly-discovered synergy between CCK and insulin.
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Affiliation(s)
- Aaron A May
- University of Cincinnati College of Medicine, Department of Pathology and Molecular Medicine, Metabolic Diseases Institute, OH, USA
| | - Min Liu
- University of Cincinnati College of Medicine, Department of Pathology and Molecular Medicine, Metabolic Diseases Institute, OH, USA
| | - Stephen C Woods
- University of Cincinnati College of Medicine, Department of Psychiatry and Behavioral Neuroscience, Metabolic Diseases Institute, OH, USA.
| | - Denovan P Begg
- University of New South Wales, School of Psychology, Sydney, NSW 2052, Australia
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Kohan AB, Wang F, Lo CM, Liu M, Tso P. ApoA-IV: current and emerging roles in intestinal lipid metabolism, glucose homeostasis, and satiety. Am J Physiol Gastrointest Liver Physiol 2015; 308:G472-81. [PMID: 25591862 PMCID: PMC4360046 DOI: 10.1152/ajpgi.00098.2014] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Apolipoprotein A-IV (apoA-IV) is secreted by the small intestine on chylomicrons into intestinal lymph in response to fat absorption. Many physiological functions have been ascribed to apoA-IV, including a role in chylomicron assembly and lipid metabolism, a mediator of reverse-cholesterol transport, an acute satiety factor, a regulator of gastric function, and, finally, a modulator of blood glucose homeostasis. The purpose of this review is to update our current view of intestinal apoA-IV synthesis and secretion and the physiological roles of apoA-IV in lipid metabolism and energy homeostasis, and to underscore the potential for intestinal apoA-IV to serve as a therapeutic target for the treatment of diabetes and obesity-related disease.
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Affiliation(s)
- Alison B. Kohan
- 2Department of Nutritional Sciences, University of Connecticut, Storrs, Connecticut
| | - Fei Wang
- 1Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio; and
| | - Chun-Min Lo
- 1Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio; and
| | - Min Liu
- 1Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio; and
| | - Patrick Tso
- 1Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio; and
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12
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Wang F, Kohan AB, Lo CM, Liu M, Howles P, Tso P. Apolipoprotein A-IV: a protein intimately involved in metabolism. J Lipid Res 2015; 56:1403-18. [PMID: 25640749 DOI: 10.1194/jlr.r052753] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Indexed: 01/07/2023] Open
Abstract
The purpose of this review is to summarize our current understanding of the physiological roles of apoA-IV in metabolism, and to underscore the potential for apoA-IV to be a focus for new therapies aimed at the treatment of diabetes and obesity-related disorders. ApoA-IV is primarily synthesized by the small intestine, attached to chylomicrons by enterocytes, and secreted into intestinal lymph during fat absorption. In circulation, apoA-IV is associated with HDL and chylomicron remnants, but a large portion is lipoprotein free. Due to its anti-oxidative and anti-inflammatory properties, and because it can mediate reverse-cholesterol transport, proposed functions of circulating apoA-IV have been related to protection from cardiovascular disease. This review, however, focuses primarily on several properties of apoA-IV that impact other metabolic functions related to food intake, obesity, and diabetes. In addition to participating in triglyceride absorption, apoA-IV can act as an acute satiation factor through both peripheral and central routes of action. It also modulates glucose homeostasis through incretin-like effects on insulin secretion, and by moderating hepatic glucose production. While apoA-IV receptors remain to be conclusively identified, the latter modes of action suggest that this protein holds therapeutic promise for treating metabolic disease.
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Affiliation(s)
- Fei Wang
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH 45237
| | - Alison B Kohan
- Department of Nutritional Sciences, University of Connecticut Advanced Technology Laboratory, Storrs, CT 06269
| | - Chun-Min Lo
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH 45237
| | - Min Liu
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH 45237
| | - Philip Howles
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH 45237
| | - Patrick Tso
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH 45237
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13
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Lo CC, Davidson WS, Hibbard SK, Georgievsky M, Lee A, Tso P, Woods SC. Intraperitoneal CCK and fourth-intraventricular Apo AIV require both peripheral and NTS CCK1R to reduce food intake in male rats. Endocrinology 2014; 155:1700-7. [PMID: 24564397 PMCID: PMC3990852 DOI: 10.1210/en.2013-1846] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Apolipoprotein AIV (Apo AIV) and cholecystokinin (CCK) are secreted in response to fat consumption, and both cause satiation via CCK 1 receptor (CCK-1R)-containing vagal afferent nerves to the nucleus of the solitary tract (NTS), where Apo AIV is also synthesized. Fasted male Long-Evans rats received ip CCK-8 or fourth-ventricular (i4vt) Apo AIV alone or in combination. Food intake and c-Fos proteins (a product of the c-Fos immediate-early gene) were assessed. i4vt Apo AIV and/or ip CCK at effective doses reduced food intake and activated c-Fos proteins in the NTS and hypothalamic arcuate nucleus and paraventricular nucleus. Blockade of the CCK-1R by i4vt lorglumide adjacent to the NTS attenuated the satiating and c-Fos-stimulating effects of CCK and Apo AIV, alone or in combination. Maintenance on a high-fat diet (HFD) for 10 weeks resulted in weight gain and attenuation of both the behavioral and c-Fos responses to a greater extent than occurred in low-fat diet-fed and pair-fed HFD animals. These observations suggest that NTS Apo AIV or/and peripheral CCK requires vagal CCK-1R signaling to elicit satiation and that maintenance on a HFD reduces the satiating capacity of these 2 signals.
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MESH Headings
- Animals
- Apolipoproteins A/administration & dosage
- Apolipoproteins A/genetics
- Apolipoproteins A/metabolism
- Apolipoproteins A/pharmacology
- Appetite Depressants/administration & dosage
- Appetite Depressants/pharmacology
- Appetite Depressants/therapeutic use
- Appetite Regulation/drug effects
- Appetite Stimulants/administration & dosage
- Appetite Stimulants/pharmacology
- Appetitive Behavior/drug effects
- Behavior, Animal/drug effects
- Cholecystokinin/administration & dosage
- Cholecystokinin/analogs & derivatives
- Cholecystokinin/antagonists & inhibitors
- Cholecystokinin/metabolism
- Diet, High-Fat/adverse effects
- Hormone Antagonists/administration & dosage
- Hormone Antagonists/pharmacology
- Infusions, Intraventricular
- Injections, Intraperitoneal
- Male
- Nerve Tissue Proteins/administration & dosage
- Nerve Tissue Proteins/agonists
- Nerve Tissue Proteins/antagonists & inhibitors
- Nerve Tissue Proteins/metabolism
- Neurons, Afferent/drug effects
- Neurons, Afferent/metabolism
- Obesity/drug therapy
- Obesity/etiology
- Obesity/metabolism
- Rats
- Rats, Long-Evans
- Receptor, Cholecystokinin A/agonists
- Receptor, Cholecystokinin A/antagonists & inhibitors
- Receptor, Cholecystokinin A/metabolism
- Recombinant Proteins/administration & dosage
- Recombinant Proteins/pharmacology
- Sincalide/administration & dosage
- Sincalide/analogs & derivatives
- Sincalide/pharmacology
- Solitary Nucleus/drug effects
- Solitary Nucleus/metabolism
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Affiliation(s)
- Chunmin C Lo
- Departments of Pathology and Laboratory Medicine (C.C.L., W.S.D., S.K.H., M.G., A.L., P.T.) and Psychiatry and Behavioral Neuroscience (S.C.W.), Metabolic Diseases Institute, University of Cincinnati, Cincinnati, Ohio 45237-0507
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Dockray GJ. Enteroendocrine cell signalling via the vagus nerve. Curr Opin Pharmacol 2013; 13:954-8. [DOI: 10.1016/j.coph.2013.09.007] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 08/28/2013] [Accepted: 09/04/2013] [Indexed: 02/06/2023]
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Abstract
Individual meals are products of a complex interaction of signals related to both short-term and long-term availability of energy stores. In addition to maintaining the metabolic demands of the individual in the short term, levels of energy intake must also maintain and defend body weight over longer periods. To accomplish this, satiety pathways are regulated by a sophisticated network of endocrine and neuroendocrine pathways. Higher brain centers modulate meal size through descending inputs to caudal brainstem regions responsible for the motor pattern generators associated with ingestion. Gastric and intestinal signals interact with central nervous system pathways to terminate food intake. These inputs can be modified as a function of internal metabolic signals, external environmental influences, and learning to regulate meal size.
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Abstract
Many peptides and other compounds that influence metabolism also influence food intake, and numerous hypotheses explaining the observed effects in terms of energy homeostasis have been suggested over the years. For example, cholecystokinin (CCK), a duodenal peptide secreted during meals that aids in digestion, also reduces ongoing food intake, thereby contributing to satiation; and insulin and leptin, hormones secreted in direct proportion to body fat, act in the brain to help control adiposity by reducing energy intake. These behavioral actions are often considered to be hard-wired, such that negative experiments, in which an administered compound fails to have its purported effect, are generally disregarded. In point of fact, failures to replicate the effects of compounds on food intake are commonplace, and this occurs both between and within laboratories. Failures to replicate have historically fueled heated debate about the efficacy and/or normal function of one or another compound, leading to confusion and ambiguity in the literature. We review these phenomena and their implications and argue that, rather than eliciting hard-wired behavioral responses in the maintenance of homeostasis, compounds that alter food intake are subjected to numerous influences that can render them completely ineffective at times and that a major reason for this variance is that food intake is not under stringent homeostatic control.
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Affiliation(s)
- Stephen C Woods
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati, OH 45237, USA.
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Lo CC, Langhans W, Georgievsky M, Arnold M, Caldwell JL, Cheng S, Liu M, Woods SC, Tso P. Apolipoprotein AIV requires cholecystokinin and vagal nerves to suppress food intake. Endocrinology 2012; 153:5857-65. [PMID: 23027805 PMCID: PMC3512075 DOI: 10.1210/en.2012-1427] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Apolipoprotein AIV (apo AIV) and cholecystokinin (CCK) are gastrointestinal satiation signals that are stimulated by fat consumption. Previous studies have demonstrated that peripheral apo AIV cannot cross the blood-brain barrier. In the present study, we hypothesized that peripheral apo AIV uses a CCK-dependent system and intact vagal nerves to relay its satiation signal to the hindbrain. To test this hypothesis, CCK-knockout (CCK-KO) mice and Long-Evan rats that had undergone subdiaphragmatic vagal deafferentation (SDA) were used. Intraperitoneal administration of apo AIV at 100 or 200 μg/kg suppressed food intake of wild-type (WT) mice at 30, 60, and 90 min. In contrast, the same dose did not reduce food intake in the CCK-KO mice. Blockade of the CCK 1 receptor by lorglumide, a CCK 1 receptor antagonist, attenuated apo AIV-induced satiation. Apo AIV at 100 μg/kg reduced food intake in SHAM rats but not in SDA rats. Furthermore, apo AIV elicited an increase in c-Fos-positive cells in the nucleus of the solitary tract (NTS), area postrema, dorsal motor nucleus of the vagus, and adjacent areas of WT mice but elicited only an attenuated increase in these same regions in CCK-KO mice. Apo AIV-induced c-Fos positive cells in the NTS and area postrema of WT mice were reduced by lorglumide. Lastly, apo AIV increased c-Fos positive cells in the NTS of SHAM rats but not in SDA rats. These observations imply that peripheral apo AIV requires an intact CCK system and vagal afferents to activate neurons in the hindbrain to reduce food intake.
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Affiliation(s)
- Chunmin C Lo
- Departments of Pathology and Laboratory Medicine, Cincinnati, OH 45237-0507, USA.
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