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Oberhauser L, Maechler P. Lipid-Induced Adaptations of the Pancreatic Beta-Cell to Glucotoxic Conditions Sustain Insulin Secretion. Int J Mol Sci 2021; 23:324. [PMID: 35008750 PMCID: PMC8745448 DOI: 10.3390/ijms23010324] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 12/22/2021] [Accepted: 12/27/2021] [Indexed: 12/16/2022] Open
Abstract
Over the last decades, lipotoxicity and glucotoxicity emerged as established mechanisms participating in the pathophysiology of obesity-related type 2 diabetes in general, and in the loss of β-cell function in particular. However, these terms hold various potential biological processes, and it is not clear what precisely they refer to and to what extent they might be clinically relevant. In this review, we discuss the basis and the last advances of research regarding the role of free fatty acids, their metabolic intracellular pathways, and receptor-mediated signaling related to glucose-stimulated insulin secretion, as well as lipid-induced β-cell dysfunction. We also describe the role of chronically elevated glucose, namely, glucotoxicity, which promotes failure and dedifferentiation of the β cell. Glucolipotoxicity combines deleterious effects of exposures to both high glucose and free fatty acids, supposedly provoking synergistic defects on the β cell. Nevertheless, recent studies have highlighted the glycerolipid/free fatty acid cycle as a protective pathway mediating active storage and recruitment of lipids. Finally, we discuss the putative correspondence of the loss of functional β cells in type 2 diabetes with a natural, although accelerated, aging process.
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Affiliation(s)
| | - Pierre Maechler
- Department of Cell Physiology and Metabolism, Faculty Diabetes Center, University of Geneva Medical Center, 1206 Geneva, Switzerland;
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Sadamura Y, Thapa S, Mizunuma R, Kambe Y, Hirasawa A, Nakamoto K, Tokuyama S, Yoshimoto K, Arita K, Miyata A, Oyoshi T, Kurihara T. FFAR1/GPR40 Contributes to the Regulation of Striatal Monoamine Releases and Facilitation of Cocaine-Induced Locomotor Activity in Mice. Front Pharmacol 2021; 12:699026. [PMID: 34489696 PMCID: PMC8417570 DOI: 10.3389/fphar.2021.699026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 07/19/2021] [Indexed: 11/13/2022] Open
Abstract
The free fatty acid receptor 1 (FFAR1) is suggested to function as a G protein-coupled receptor (GPR40) for medium-to-long-chain free fatty acids. Previous studies on the expression of FFAR1 revealed that the nigrostriatal region is one of the areas which express abundant FFAR1 mRNA/protein in the central nervous system (CNS). However, the role of FFAR1 in the CNS has been still largely unclarified. Here, we examined a possible functional role of FFAR1 in the control of extracellular concentrations of striatal monoamines and cocaine-induced locomotor activity. Microdialysis analysis revealed that the basal level of extracellular dopamine (DA) was significantly elevated, while the basal serotonin (5-HT) level tended to be reduced in the striatum of FFAR1 knockout (-/-) mice. Interestingly, local application of a FFAR1 agonist, GW9508, markedly augmented the striatal 5-HT release in FFAR1 wild-type (+/+) mice, whereas topical application of a FFAR1 antagonist, GW1100, significantly reduced the 5-HT release. However, the enhanced 5-HT release was completely lost in -/- mice. Although acute administration of cocaine enhanced the locomotor activity in both +/+ and -/- mice, the magnitude of the enhancement was significantly reduced in -/- mice. In addition, intraperitoneal injection of GW1100 significantly decreased the cocaine-induced locomotor enhancement. These results suggest that FFAR1 has a facilitatory role in striatal 5-HT release, and the evoked 5-HT release might contribute to enhance cocaine-induced locomotor activity.
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Affiliation(s)
- Yuko Sadamura
- Department of Pharmacology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan.,Department of Neurosurgery, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Shanta Thapa
- Department of Pharmacology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan.,Department of Neurosurgery, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Ryota Mizunuma
- Department of Pharmacology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Yuki Kambe
- Department of Pharmacology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Akira Hirasawa
- Department of Genomic Drug Discovery Science, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Kazuo Nakamoto
- Department of Clinical Pharmacy, School of Pharmaceutical Sciences, Kobe Gakuin University, Hyogo, Japan
| | - Shogo Tokuyama
- Department of Clinical Pharmacy, School of Pharmaceutical Sciences, Kobe Gakuin University, Hyogo, Japan
| | - Koji Yoshimoto
- Department of Neurosurgery, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Kazunori Arita
- Department of Neurosurgery, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Atsuro Miyata
- Department of Pharmacology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Tatsuki Oyoshi
- Department of Neurosurgery, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Takashi Kurihara
- Department of Pharmacology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
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Towers AE, Oelschlager ML, Juda MB, Jain S, Gainey SJ, Freund GG. HFD refeeding in mice after fasting impairs learning by activating caspase-1 in the brain. Metabolism 2020; 102:153989. [PMID: 31697963 PMCID: PMC6906226 DOI: 10.1016/j.metabol.2019.153989] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 09/10/2019] [Accepted: 10/01/2019] [Indexed: 01/07/2023]
Abstract
BACKGROUND Diets that include some aspect of fasting have dramatically increased in popularity. In addition, fasting reduces inflammasome activity in the brain while improving learning. Here, we examine the impact of refeeding a low-fat diet (LFD) or high-fat diet (HFD) after fasting. METHODS Male wildtype (WT), caspase-1 knockout (KO) and/or IL-1 receptor 1 (IL-1R1) KO mice were fasted for 24 h or allowed ad libitum access to food (chow). Immediately after fasting, mice were allowed to refeed for 2 h in the presence of LFD, HFD or chow. Mouse learning was examined using novel object recognition (NOR) and novel location recognition (NLR). Caspase-1 activity was quantified in the brain using histochemistry (HC) and image analysis. RESULTS Refeeding with a HFD but not a LFD or chow fully impaired both NOR and NLR. Likewise, HFD when compared to LFD refeeding increased caspase-1 activity in the whole amygdala and, particularly, in the posterior basolateral nuclei (BLp) by 2.5-fold and 4.6-fold, respectively. When caspase-1 KO or IL-1R1 KO mice were examined, learning impairment secondary to HFD refeeding did not occur. Equally, administration of n-acetylcysteine to fasted WT mice prevented HFD-dependent learning impairment and caspase-1 activation in the BLp. Finally, the free-fatty acid receptor 1 (FFAR1) antagonist, DC260126, mitigated learning impairment associated with HFD refeeding while blocking caspase-1 activation in the BLp. CONCLUSIONS Consumption of a HFD after fasting impairs learning by a mechanism that is dependent on caspase-1 and the IL-1R1 receptor. These consequences of a HFD refeeding on the BLP of the amygdala appear linked to oxidative stress and FFAR1.
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Affiliation(s)
- Albert E Towers
- Division of Nutritional Sciences, University of Illinois, Urbana, IL, USA
| | | | - Michal B Juda
- Department of Pathology, Program in Integrative Immunology and Behavior, University of Illinois, Urbana, IL, USA
| | - Sparsh Jain
- School of Molecular and Cellular Biology, University of Illinois, Urbana, IL, USA
| | - Stephen J Gainey
- Department of Animal Sciences, University of Illinois, Urbana, IL, USA
| | - Gregory G Freund
- Division of Nutritional Sciences, University of Illinois, Urbana, IL, USA; Department of Animal Sciences, University of Illinois, Urbana, IL, USA; Department of Pathology, Program in Integrative Immunology and Behavior, University of Illinois, Urbana, IL, USA.
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Li Y, Lu Z, Ru JH, Lopes-Virella MF, Lyons TJ, Huang Y. Saturated fatty acid combined with lipopolysaccharide stimulates a strong inflammatory response in hepatocytes in vivo and in vitro. Am J Physiol Endocrinol Metab 2018; 315:E745-E757. [PMID: 29989851 PMCID: PMC6293169 DOI: 10.1152/ajpendo.00015.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease and consumption of high-fat diet (HFD) is a risk factor for NAFLD. The HFD not only increases intake of saturated fatty acid (SFA) but also induces metabolic endotoxemia, an HFD-associated increase in circulating lipopolysaccharide (LPS). Although it is known that SFA or LPS promote hepatic inflammation, a hallmark of NAFLD, it remains unclear how SFA in combination with LPS stimulates host inflammatory response in hepatocytes. In this study, we performed both in vivo and in vitro experiments to investigate the effect of SFA in combination with LPS on proinflammatory gene expression in hepatocytes. Our animal study showed that feeding low-density lipoprotein-deficient mice HFD enriched with SFA and injection of low-dose LPS cooperatively stimulated IL-6 expression in livers. To understand how SFA and LPS interact to promote IL-6 expression, our in vitro studies showed that palmitic acid (PA), a major SFA, and LPS exerted synergistic effect on the expression of IL-6 in hepatocytes. Furthermore, coculture of hepatocytes with macrophages resulted in a greater IL-6 expression than culture of hepatocytes without macrophages in response to the combination of PA and LPS. Finally, we observed that LPS and PA increased ceramide production by cooperatively stimulating ceramide de novo synthesis, which played an essential role in the synergistic stimulation of proinflammatory gene expression by LPS and PA. Taken together, this study showed that SFA in combination with LPS stimulated a strong inflammatory response in hepatocytes in vivo and in vitro.
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Affiliation(s)
- Yanchun Li
- Division of Endocrinology, Diabetes and Medical Genetics, Department of Medicine, College of Medicine Medical University of South Carolina, South Carolina
| | - Zhongyang Lu
- Ralph H. Johnson Veterans Affairs Medical Center , Charleston, South Carolina
| | - Ji Hyun Ru
- Division of Endocrinology, Diabetes and Medical Genetics, Department of Medicine, College of Medicine Medical University of South Carolina, South Carolina
| | - Maria F Lopes-Virella
- Division of Endocrinology, Diabetes and Medical Genetics, Department of Medicine, College of Medicine Medical University of South Carolina, South Carolina
- Ralph H. Johnson Veterans Affairs Medical Center , Charleston, South Carolina
| | - Timothy J Lyons
- Division of Endocrinology, Diabetes and Medical Genetics, Department of Medicine, College of Medicine Medical University of South Carolina, South Carolina
| | - Yan Huang
- Division of Endocrinology, Diabetes and Medical Genetics, Department of Medicine, College of Medicine Medical University of South Carolina, South Carolina
- Ralph H. Johnson Veterans Affairs Medical Center , Charleston, South Carolina
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