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Li X, Zheng L, Zhang B, Deng ZY, Luo T. The Structure Basis of Phytochemicals as Metabolic Signals for Combating Obesity. Front Nutr 2022; 9:913883. [PMID: 35769384 PMCID: PMC9234462 DOI: 10.3389/fnut.2022.913883] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 05/23/2022] [Indexed: 12/12/2022] Open
Abstract
The consumption of phytochemicals, bioactive compounds in fruits and vegetables, has been demonstrated to ameliorate obesity and related metabolic symptoms by regulating specific metabolic pathways. This review summarizes the progress made in our understanding of the potential of phytochemicals as metabolic signals: we discuss herein selected molecular mechanisms which are involved in the occurrence of obesity that may be regulated by phytochemicals. The focus of our review highlights the regulation of transcription factors toll like receptor 4 (TLR4), nuclear factor (erythroid-derived 2)-like 2 (Nrf2), the peroxisome proliferator-activated receptors (PPARs), fat mass and obesity-associated protein (FTO) and regulation of microRNAs (miRNA). In this review, the effect of phytochemicals on signaling pathways involved in obesity were discussed on the basis of their chemical structure, suggesting molecular mechanisms for how phytochemicals may impact these signaling pathways. For example, compounds with an isothiocyanate group or an α, β-unsaturated carbonyl group may interact with the TLR4 signaling pathway. Regarding Nrf2, we examine compounds possessing an α, β-unsaturated carbonyl group which binds covalently with the cysteine thiols of Keap1. Additionally, phytochemical activation of PPARs, FTO and miRNAs were summarized. This information may be of value to better understand how specific phytochemicals interact with specific signaling pathways and help guide the development of new drugs to combat obesity and related metabolic diseases.
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Altman MK, Schaub CM, Dadi PK, Dickerson MT, Zaborska KE, Nakhe AY, Graff SM, Galletta TJ, Amarnath G, Thorson AS, Gu G, Jacobson DA. TRPM7 is a crucial regulator of pancreatic endocrine development and high-fat-diet-induced β-cell proliferation. Development 2021; 148:271182. [PMID: 34345920 DOI: 10.1242/dev.194928] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 07/20/2021] [Indexed: 12/31/2022]
Abstract
The melastatin subfamily of the transient receptor potential channels (TRPM) are regulators of pancreatic β-cell function. TRPM7 is the most abundant islet TRPM channel; however, the role of TRPM7 in β-cell function has not been determined. Here, we used various spatiotemporal transgenic mouse models to investigate how TRPM7 knockout influences pancreatic endocrine development, proliferation and function. Ablation of TRPM7 within pancreatic progenitors reduced pancreatic size, and α-cell and β-cell mass. This resulted in modestly impaired glucose tolerance. However, TRPM7 ablation following endocrine specification or in adult mice did not impact endocrine expansion or glucose tolerance. As TRPM7 regulates cell proliferation, we assessed how TRPM7 influences β-cell hyperplasia under insulin-resistant conditions. β-Cell proliferation induced by high-fat diet was significantly decreased in TRPM7-deficient β-cells. The endocrine roles of TRPM7 may be influenced by cation flux through the channel, and indeed we found that TRPM7 ablation altered β-cell Mg2+ and reduced the magnitude of elevation in β-cell Mg2+ during proliferation. Together, these findings revealed that TRPM7 controls pancreatic development and β-cell proliferation, which is likely due to regulation of Mg2+ homeostasis.
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Affiliation(s)
- Molly K Altman
- Department of Molecular Physiology and Biophysics, Vanderbilt University, 7425B MRB IV, 2213 Garland Ave., Nashville, TN 37232, USA
| | - Charles M Schaub
- Department of Molecular Physiology and Biophysics, Vanderbilt University, 7425B MRB IV, 2213 Garland Ave., Nashville, TN 37232, USA
| | - Prasanna K Dadi
- Department of Molecular Physiology and Biophysics, Vanderbilt University, 7425B MRB IV, 2213 Garland Ave., Nashville, TN 37232, USA
| | - Matthew T Dickerson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, 7425B MRB IV, 2213 Garland Ave., Nashville, TN 37232, USA
| | - Karolina E Zaborska
- Department of Molecular Physiology and Biophysics, Vanderbilt University, 7425B MRB IV, 2213 Garland Ave., Nashville, TN 37232, USA
| | - Arya Y Nakhe
- Department of Molecular Physiology and Biophysics, Vanderbilt University, 7425B MRB IV, 2213 Garland Ave., Nashville, TN 37232, USA
| | - Sarah M Graff
- Department of Molecular Physiology and Biophysics, Vanderbilt University, 7425B MRB IV, 2213 Garland Ave., Nashville, TN 37232, USA
| | - Thomas J Galletta
- Department of Molecular Physiology and Biophysics, Vanderbilt University, 7425B MRB IV, 2213 Garland Ave., Nashville, TN 37232, USA
| | - Gautami Amarnath
- Department of Molecular Physiology and Biophysics, Vanderbilt University, 7425B MRB IV, 2213 Garland Ave., Nashville, TN 37232, USA.,Molecular Neurophysiology, Institute of Applied Physiology, University of Ulm, 89081 Ulm, Germany
| | - Ariel S Thorson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, 7425B MRB IV, 2213 Garland Ave., Nashville, TN 37232, USA
| | - Guoqiang Gu
- Vanderbilt Program in Developmental Biology, Vanderbilt Center for Stem Cell Biology, Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - David A Jacobson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, 7425B MRB IV, 2213 Garland Ave., Nashville, TN 37232, USA
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Kim JW, Luo JZ, Luo L. The Biochemical Cascades of the Human Pancreatic β-Cells: The Role of MicroRNAs. JOURNAL OF BIOANALYSIS & BIOMEDICINE 2015; 7:e133. [PMID: 28503255 PMCID: PMC5426857 DOI: 10.4172/1948-593x.1000e133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Diabetes mellitus is a disease that poses a burden to the health care system due to its prevalence and chronic nature. Understanding β cell pathophysiology may lead to future therapeutic options for diabetes mellitus type 1 and 2. MicroRNAs (MiR) fine-tune β cell biochemical cascades through specific protein targets. This review argues that miRs may play a critical role in human islet β cell biology and are potential candidates for a new pharmacological strategy. We have reviewed and presented how miRs fine tune four biochemical cascades in islet β cells: glucose stimulated insulin secretion, β cell replication, apoptosis, and development. Only studies that examine human pancreatic islets either in vitro or in vivo are included. The unveiling role of miR pathways in regulating human islet β cell biology could open the door for diagnostic and therapeutic methods for diabetes mellitus prevention and therapy.
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Affiliation(s)
- Joseph W Kim
- Department of Internal Medicine, Roger Williams Hospital, Boston University School of Medicine, Providence, RI, USA
| | - John Z Luo
- Department of Internal Medicine, Roger Williams Hospital, Boston University School of Medicine, Providence, RI, USA
- Doctor’s Choice LLC, Warwick, RI, USA
| | - Luguang Luo
- Department of Internal Medicine, Roger Williams Hospital, Boston University School of Medicine, Providence, RI, USA
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Hogh KLN, Craig MN, Uy CE, Nygren H, Asadi A, Speck M, Fraser JD, Rudecki AP, Baker RK, Orešič M, Gray SL. Overexpression of PPARγ specifically in pancreatic β-cells exacerbates obesity-induced glucose intolerance, reduces β-cell mass, and alters islet lipid metabolism in male mice. Endocrinology 2014; 155:3843-52. [PMID: 25051434 DOI: 10.1210/en.2014-1076] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The contribution of peroxisomal proliferator-activated receptor (PPAR)-γ agonism in pancreatic β-cells to the antidiabetic actions of thiazolidinediones has not been clearly elucidated. Genetic models of pancreatic β-cell PPARγ ablation have revealed a potential role for PPARγ in β-cell expansion in obesity but a limited role in normal β-cell physiology. Here we overexpressed PPARγ1 or PPARγ2 specifically in pancreatic β-cells of mice subjected to high-fat feeding using an associated adenovirus (β-PPARγ1-HFD and β-PPARγ2-HFD mice). We show β-cell-specific PPARγ1 or PPARγ2 overexpression in diet-induced obese mice exacerbated obesity-induced glucose intolerance with decreased β-cell mass, increased islet cell apoptosis, and decreased plasma insulin compared with obese control mice (β-eGFP-HFD mice). Analysis of islet lipid composition in β-PPARγ2-HFD mice revealed no significant changes in islet triglyceride content and an increase in only one of eight ceramide species measured. Interestingly β-PPARγ2-HFD islets had significantly lower levels of lysophosphatidylcholines, lipid species shown to enhance insulin secretion in β-cells. Gene expression profiling revealed increased expression of uncoupling protein 2 and genes involved in fatty acid transport and β-oxidation. In summary, transgenic overexpression of PPARγ in β-cells in diet-induced obesity negatively impacts whole-animal carbohydrate metabolism associated with altered islet lipid content, increased expression of β-oxidative genes, and reduced β-cell mass.
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Affiliation(s)
- K-Lynn N Hogh
- Northern Medical Program (K.N.H., M.N.C., C.E.U., J.D.F., A.P.R., S.L.G.), University of Northern British Columbia, Prince George, British Columbia, Canada V2N 4Z9; Department of Cellular and Physiological Sciences and Faculty of Medicine (A.A., R.K.B.), University of British Columbia, Vancouver, British Columbia, Canada V5Z 4H4; VTT Technical Research Centre of Finland (H.N., M.O.), Espoo FI-02044, Finland; Steno Diabetes Center A/S (H.N., M.O.), Gentofte, Denmark; and Child and Family Research Institute (M.S.), Vancouver, British Columbia, Canada V6T 1Z1
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Abstract
Free fatty acids (FFAs) exert both positive and negative effects on beta cell survival and insulin secretory function, depending on concentration, duration, and glucose abundance. Lipid signals are mediated not only through metabolic pathways, but also through cell surface and nuclear receptors. Toxicity is modulated by positive signals arising from circulating factors such as hormones, growth factors and incretins, as well as negative signals such as inflammatory mediators and cytokines. Intracellular mechanisms of lipotoxicity include metabolic interference and cellular stress responses such as oxidative stress, endoplasmic reticulum (ER) stress, and possibly autophagy. New findings strengthen an old hypothesis that lipids may also impair compensatory beta cell proliferation. Clinical observations continue to support a role for lipid biology in the risk and progression of both type 1 (T1D) and type 2 diabetes (T2D). This review summarizes recent work in this important, rapidly evolving field.
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Affiliation(s)
- Rohit B Sharma
- Diabetes Center of Excellence, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01605, USA
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