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Marku A, Da Dalt L, Galli A, Dule N, Corsetto P, Rizzo AM, Moregola A, Uboldi P, Bonacina F, Marciani P, Castagna M, Catapano AL, Norata GD, Perego C. Pancreatic PCSK9 controls the organization of the β-cell secretory pathway via LDLR-cholesterol axis. Metabolism 2022; 136:155291. [PMID: 35981632 DOI: 10.1016/j.metabol.2022.155291] [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: 05/23/2022] [Revised: 07/29/2022] [Accepted: 08/11/2022] [Indexed: 11/15/2022]
Abstract
BACKGROUND Cholesterol is central to pancreatic β-cell physiology and alterations of its homeostasis contribute to β-cell dysfunction and diabetes. Proper intracellular cholesterol levels are maintained by different mechanisms including uptake via the low-density lipoprotein receptor (LDLR). In the liver, the proprotein convertase subtilisin/kexin type 9 (PCSK9) routes the LDLR to lysosomes for degradation, thus limiting its recycling to the membrane. PCSK9 is also expressed in the pancreas and loss of function mutations of PCSK9 result in higher plasma glucose levels and increased risk of Type 2 diabetes mellitus. Aim of this study was to investigate whether PCSK9 also impacts β-cells function. METHODS Pancreas-specific Pcsk9 null mice (Pdx1Cre/Pcsk9 fl/fl) were generated and characterized for glucose tolerance, insulin release and islet morphology. Isolated Pcsk9-deficient islets and clonal β-cells (INS1E) were employed to characterize the molecular mechanisms of PCSK9 action. RESULTS Pdx1Cre/Pcsk9 fl/fl mice exhibited normal blood PCSK9 and cholesterol levels but were glucose intolerant and had defective insulin secretion in vivo. Analysis of PCSK9-deficient islets revealed comparable β-cell mass and insulin content but impaired stimulated secretion. Increased proinsulin/insulin ratio, modifications of SNARE proteins expression and decreased stimulated‑calcium dynamics were detected in PCSK9-deficient β-cells. Mechanistically, pancreatic PCSK9 silencing impacts β-cell LDLR expression and cholesterol content, both in vivo and in vitro. The key role of LDLR is confirmed by the demonstration that LDLR downregulation rescued the phenotype. CONCLUSIONS These findings establish pancreatic PCSK9 as a novel critical regulator of the functional maturation of the β-cell secretory pathway, via modulation of cholesterol homeostasis.
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Affiliation(s)
- Algerta Marku
- Dept of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20134 Milan, Italy
| | - Lorenzo Da Dalt
- Dept of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20134 Milan, Italy
| | - Alessandra Galli
- Dept of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20134 Milan, Italy
| | - Nevia Dule
- Dept of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20134 Milan, Italy
| | - Paola Corsetto
- Dept of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20134 Milan, Italy
| | - Angela Maria Rizzo
- Dept of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20134 Milan, Italy
| | - Annalisa Moregola
- Dept of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20134 Milan, Italy
| | - Patrizia Uboldi
- Dept of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20134 Milan, Italy
| | - Fabrizia Bonacina
- Dept of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20134 Milan, Italy
| | - Paola Marciani
- Dept of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20134 Milan, Italy
| | - Michela Castagna
- Dept of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20134 Milan, Italy
| | - Alberico Luigi Catapano
- Dept of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20134 Milan, Italy; IRCCS Multimedica Hospital, Sesto San Giovanni, 20099 Milan, Italy
| | - Giuseppe Danilo Norata
- Dept of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20134 Milan, Italy; Centro SISA per lo studio dell'Aterosclerosi, Ospedale Bassini, 20092 Cinisello Balsamo, Italy.
| | - Carla Perego
- Dept of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20134 Milan, Italy.
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Ji L, Li Q, He Y, Zhang X, Zhou Z, Gao Y, Fang M, Yu Z, Rodrigues RM, Gao Y, Li M. Therapeutic potential of traditional Chinese medicine for the treatment of NAFLD: a promising drug Potentilla discolor Bunge. Acta Pharm Sin B 2022; 12:3529-3547. [PMID: 36176915 PMCID: PMC9513494 DOI: 10.1016/j.apsb.2022.05.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 02/09/2022] [Accepted: 03/23/2022] [Indexed: 11/29/2022] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is characterized by excessive accumulation of hepatic lipids and metabolic stress-induced liver injury. There are currently no approved effective pharmacological treatments for NAFLD. Traditional Chinese medicine (TCM) has been used for centuries to treat patients with chronic liver diseases without clear disease types and mechanisms. More recently, TCM has been shown to have unique advantages in the treatment of NAFLD. We performed a systematic review of the medical literature published over the last two decades and found that many TCM formulas have been reported to be beneficial for the treatment of metabolic dysfunctions, including Potentilla discolor Bunge (PDB). PDB has a variety of active compounds, including flavonoids, terpenoids, organic acids, steroids and tannins. Many compounds have been shown to exhibit a series of beneficial effects for the treatment of NAFLD, including anti-oxidative and anti-inflammatory functions, improvement of lipid metabolism and reversal of insulin resistance. In this review, we summarize potential therapeutic effects of TCM formulas for the treatment of NAFLD, focusing on the medicinal properties of natural active compounds from PDB and their underlying mechanisms. We point out that PDB can be classified as a novel candidate for the treatment and prevention of NAFLD.
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Affiliation(s)
- Longshan Ji
- Laboratory of Cellular Immunity, Institute of Clinical Immunology, Shanghai Key Laboratory of Traditional Chinese Medicine, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Key Laboratory of Liver and Kidney Diseases (Shanghai University of Traditional Chinese Medicine), Ministry of Education, Shanghai 201203, China
| | - Qian Li
- Laboratory of Cellular Immunity, Institute of Clinical Immunology, Shanghai Key Laboratory of Traditional Chinese Medicine, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Key Laboratory of Liver and Kidney Diseases (Shanghai University of Traditional Chinese Medicine), Ministry of Education, Shanghai 201203, China
| | - Yong He
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Xin Zhang
- Laboratory of Cellular Immunity, Institute of Clinical Immunology, Shanghai Key Laboratory of Traditional Chinese Medicine, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Key Laboratory of Liver and Kidney Diseases (Shanghai University of Traditional Chinese Medicine), Ministry of Education, Shanghai 201203, China
| | - Zhenhua Zhou
- Department of Hepatopathy, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Yating Gao
- Laboratory of Cellular Immunity, Institute of Clinical Immunology, Shanghai Key Laboratory of Traditional Chinese Medicine, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Key Laboratory of Liver and Kidney Diseases (Shanghai University of Traditional Chinese Medicine), Ministry of Education, Shanghai 201203, China
| | - Miao Fang
- Laboratory of Cellular Immunity, Institute of Clinical Immunology, Shanghai Key Laboratory of Traditional Chinese Medicine, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Key Laboratory of Liver and Kidney Diseases (Shanghai University of Traditional Chinese Medicine), Ministry of Education, Shanghai 201203, China
| | - Zhuo Yu
- Department of Hepatopathy, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Robim M. Rodrigues
- Department of in Vitro Toxicology and Dermato-Cosmetology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Brussels 1000, Belgium
- Corresponding authors.
| | - Yueqiu Gao
- Laboratory of Cellular Immunity, Institute of Clinical Immunology, Shanghai Key Laboratory of Traditional Chinese Medicine, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Key Laboratory of Liver and Kidney Diseases (Shanghai University of Traditional Chinese Medicine), Ministry of Education, Shanghai 201203, China
- Corresponding authors.
| | - Man Li
- Laboratory of Cellular Immunity, Institute of Clinical Immunology, Shanghai Key Laboratory of Traditional Chinese Medicine, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Key Laboratory of Liver and Kidney Diseases (Shanghai University of Traditional Chinese Medicine), Ministry of Education, Shanghai 201203, China
- Corresponding authors.
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Nuclear Receptors in Pregnancy and Outcomes: Clinical Perspective. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1390:3-19. [DOI: 10.1007/978-3-031-11836-4_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Gresch A, Noguera Hurtado H, Wörmeyer L, De Luca V, Wiggers R, Seebohm G, Wünsch B, Düfer M. Selective Inhibition of NMDA receptors with GluN2B subunit protects beta cells against stress-induced apoptotic cell death. J Pharmacol Exp Ther 2021; 379:235-244. [PMID: 34593560 DOI: 10.1124/jpet.121.000807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 09/28/2021] [Indexed: 11/22/2022] Open
Abstract
Participation of NMDA receptors (NMDARs) in the failure of pancreatic beta cells during development of type 2 diabetes mellitus is discussed. Our study investigates whether beta cell mass and function can be preserved by selectively addressing the GluN2B subunit of the NMDAR. NMDAR activation by NMDA and its co-agonist glycine moderately influenced electrical activity and Ca2+ handling in islet cells at a threshold glucose concentration (4-5 mM) without affecting glucose-mediated insulin secretion. Exposure of islet cells to NMDA/glycine or a glucolipotoxic milieu increased apoptosis by 5 and 8 %, respectively. The GluN2B-specific NMDAR antagonist WMS-1410 (0.1 and 1 µM) partly protected against this. In addition, WMS-1410 completely prevented the decrease in insulin secretion of about 32 % provoked by a 24-h-treatment with NMDA/glycine. WMS-1410 eliminated NMDA-induced changes in the oxidation status of the islet cells and elevated the sensitivity of intracellular calcium to 15 mM glucose. By contrast, WMS-1410 did not prevent the decline in glucose-stimulated insulin secretion occurring after glucolipotoxic culture. This lack of effect was due to a decrease in insulin content to 18 % that obviously could not be compensated by the preservation of cell mass or the higher percentage of insulin release in relation to insulin content. In conclusion, the negative effects of permanent NMDAR activation were effectively counteracted by WMS-1410 as well as the apoptotic cell death induced by high glucose and lipid concentrations. Modulation of NMDARs containing the GluN2B subunit is suggested to preserve beta cell mass during development of type 2 diabetes mellitus. Significance Statement Addressing NMDA receptors containing the GluN2B subunit in pancreatic islet cells has the potential to protect the beta cell mass that progressively declines during the development of type 2 diabetes. Furthermore, this study shows that harmful effects of permanent NMDAR activation can be effectively counteracted by the compound WMS-1410, a selective modulator for NMDARs containing the GluN2B subunit.
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Affiliation(s)
- Anne Gresch
- Pharmacology, Institute for Pharmaceutical and Medical Chemistry, Germany
| | | | - Laura Wörmeyer
- Pharmaceutical and Medicinal Chemistry, University of Münster, Germany
| | - Vivien De Luca
- Pharmaceutical and Medicinal Chemistry, University of Münster, Germany
| | - Rebekka Wiggers
- Pharmaceutical and Medicinal Chemistry, University of Münster, Germany
| | - Guiscard Seebohm
- Institute for Genetics of Heart Diseases, University Hospital Münster, Germany
| | - Bernhard Wünsch
- Fachbereich Chemie und Pharmazie, Institut für Pharmazeutische und Medizinische Chemie, Germany
| | - Martina Düfer
- Pharmaceutical and Medicinal Chemistry, University of Münster, Germany
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Kim JK, Cho IJ, Kim EO, Lee DG, Jung DH, Ki SH, Ku SK, Kim SC. Hemistepsin A inhibits T0901317-induced lipogenesis in the liver. BMB Rep 2021. [PMID: 32843130 PMCID: PMC7907741 DOI: 10.5483/bmbrep.2021.54.2.111] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Affiliation(s)
- Jae Kwang Kim
- College of Korean Medicine, Daegu Haany University, Gyeongsan 38610, Korea
- Korean Medicine-Application Center, Korea Institute of Oriental Medicine, Daegu 41062, Korea
| | - Il Je Cho
- College of Korean Medicine, Daegu Haany University, Gyeongsan 38610, Korea
| | - Eun Ok Kim
- College of Korean Medicine, Daegu Haany University, Gyeongsan 38610, Korea
| | - Dae Geon Lee
- College of Korean Medicine, Daegu Haany University, Gyeongsan 38610, Korea
| | - Dae Hwa Jung
- College of Korean Medicine, Daegu Haany University, Gyeongsan 38610, Korea
- Hani Bio Co., Ltd, Daegu 41059, Korea
| | - Sung Hwan Ki
- College of Pharmacy, Chosun University, Gwangju 61452, Korea
| | - Sae Kwang Ku
- College of Korean Medicine, Daegu Haany University, Gyeongsan 38610, Korea
| | - Sang Chan Kim
- College of Korean Medicine, Daegu Haany University, Gyeongsan 38610, Korea
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Kaiser J, Krippeit-Drews P, Drews G. Acyl-Ghrelin Influences Pancreatic β-Cell Function by Interference with K ATP Channels. Diabetes 2021; 70:423-435. [PMID: 33154069 DOI: 10.2337/db20-0231] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 11/03/2020] [Indexed: 11/13/2022]
Abstract
The aim for this study was to elucidate how the hypothalamic hunger-inducing hormone acyl-ghrelin (AG), which is also produced in the pancreas, affects β-cell function, with particular attention to the role of ATP-sensitive K+ (KATP) channels and the exact site of action of the hormone. AG hyperpolarized the membrane potential and decreased cytoplasmic calcium concentration [Ca2+]c and glucose-stimulated insulin secretion (GSIS). These effects were abolished in β-cells from SUR1-knockout (KO) mice. AG increased KATP current but only in a configuration with intact metabolism. Unacylated ghrelin counteracted the effects of AG. The influence of AG on membrane potential and GSIS could only be averted in the combined presence of a ghrelin receptor (GHSR1a) antagonist and an inverse agonist. The inhibition of GSIS by AG could be prevented by dibutyryl cyclic-cAMP or 3-isobutyl-1-methylxanthine and the somatostatin (SST) receptor 2-5 antagonist H6056. These data indicate that AG indirectly opens KATP channels probably by interference with the cAMP/cAMP-dependent protein kinase pathway, resulting in a decrease of [Ca2+]c and GSIS. The experiments with SUR1-KO β-cells point to a direct effect of AG on β-cells and not, as earlier suggested, to an exclusive effect by AG-induced SST release from δ-cells. Nevertheless, SST receptors may be involved in the effect of AG, possibly by heteromerization of AG and SST receptors.
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Affiliation(s)
- Julia Kaiser
- Department of Pharmacology, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Peter Krippeit-Drews
- Department of Pharmacology, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Gisela Drews
- Department of Pharmacology, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
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Sadeghi MB, Nakhaee A, Saravani R, Sargazi S. Significant association of LXRβ (NR1H2) polymorphisms (rs28514894, rs2303044) with type 2 diabetes mellitus and laboratory characteristics. J Diabetes Metab Disord 2021; 20:261-270. [PMID: 34178836 DOI: 10.1007/s40200-021-00740-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Accepted: 01/10/2021] [Indexed: 02/07/2023]
Abstract
Purpose To investigate if single-nucleotide polymorphisms (SNPs) in the NR1H2 gene encoding LXRβ contribute to the development of type-2 diabetes mellitus (T2DM) and whether genotypes of two NR1H2 polymorphisms, rs28514894 and rs2303044, are associated with laboratory characteristics of T2DM patients. Method A total of 900 subjects (450 T2DM cases and 450 healthy subjects) of Iranian ancestry were genotyped for NR1H2 polymorphisms via ARMS-PCR and PCR-RFLP techniques. Result Our findings showed a significant correlation between both polymorphisms and increased risk of T2DM. The haplotype analysis showed an association between the C A haplotype with enhanced risk of T2DM. In T2DM patients, the mean level of HbA1C and BUN significantly differed among carriers of CC and TT genotypes of the rs28514894 polymorphism (P = 0.05 and P < 0.0001, respectively); while in the control group, no significant difference was noticed between subjects with these genotypes. The mean BUN levels also significantly differed among carriers of TC and TT genotypes of this variant in T2DM patients (P = 0.01) and controls (P = 0.04). As for rs2303044 polymorphism, only the mean BUN level significantly differed between GA and GG carriers in T2DM patients (P = 0.006). Compared with CT and TT genotypes, the CC genotype of rs28514894 polymorphism was more frequent in overweight T2DM patients ( 25 < body mass index < 30). Conclusions The present research provided the first documents of the correlation of NR1H2 rs28514894 and rs2303044 polymorphisms with susceptibility to T2DM. Replicated case-control studies on larger populations are needed to validate these findings.
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Affiliation(s)
- Mohammad Bagher Sadeghi
- Department of Clinical Biochemistry, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran.,Cellular and Molecular Research Center, Resistant Tuberculosis Institute, Zahedan University of Medical Sciences, Zahedan, Iran
| | - Alireza Nakhaee
- Department of Clinical Biochemistry, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran.,Cellular and Molecular Research Center, Resistant Tuberculosis Institute, Zahedan University of Medical Sciences, Zahedan, Iran
| | - Ramin Saravani
- Department of Clinical Biochemistry, School of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran.,Cellular and Molecular Research Center, Resistant Tuberculosis Institute, Zahedan University of Medical Sciences, Zahedan, Iran
| | - Saman Sargazi
- Cellular and Molecular Research Center, Resistant Tuberculosis Institute, Zahedan University of Medical Sciences, Zahedan, Iran
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Pharmacokinetics of T0901317 in mouse serum and tissues using a validated UFLC-IT-TOF/MS method. J Pharm Biomed Anal 2020; 189:113420. [PMID: 32593849 DOI: 10.1016/j.jpba.2020.113420] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 06/04/2020] [Accepted: 06/07/2020] [Indexed: 01/08/2023]
Abstract
T0901317, a liver X receptors (LXRs) agonist with high-affinity, is widely used to explore the functions of LXRs in various diseases such as atherosclerosis and Alzheimer's disease. However, there is currently little information available about the pharmacokinetics (PK) behavior of T0901317. Here we established a novel ultrafast liquid chromatography-high resolution mass spectrometry method to quantify the concentration of T0901317 in serum, liver, and brain. The chromatographic separation was attained on a C18 (2.1 × 100 mm, 1.8 μm) column using acetonitrile and 0.1 % of formic acid in water as mobile phase operated in gradient elution mode. The mass detection was carried out using negative ions m/z 479.9809 and 322.0882 for T0901317 and internal standard, respectively. The proposed method was fully validated according to the FDA guidelines, and it generally provides good results in terms of linearity (r2 > 0.99), precision (RSD < 18 % and 12 % for LLOQ and other QC levels, respectively), accuracy (between 92.30 % and 108.16 %), and matrix effect (between 86.56 % and 113.81 %). We then for the first time determined and computed the PK parameters of T0901317 in mouse after intraperitoneal administration of a 20 mg/kg dosage. The peak times (Tmax) in serum, liver, and brain were 1.5, 1.5, and 4 h, respectively, while the half-lives (t1/2) were 4.9, 3.3, and 4.5 h, respectively. Taken together, our results provide a significant choice to study the PK property of T0901317, from which the design of the dosing and sampling protocols of LXRs receptor-antagonist experiments employing T0901317 can also benefit.
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Maczewsky J, Kaiser J, Krippeit-Drews P, Drews G. Approved LXR agonists exert unspecific effects on pancreatic β-cell function. Endocrine 2020; 68:526-535. [PMID: 32146655 PMCID: PMC7308254 DOI: 10.1007/s12020-020-02241-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 02/24/2020] [Indexed: 12/20/2022]
Abstract
Novel agonists of the nuclear liver-X-receptor (LXR) are designed to treat metabolic disorders or cancer. The rationale to develop these new drugs is based on promising results with established LXR agonist like T0901317 and GW3965. LXRα and LXRβ are expressed in β-cells, and expression is increased by T0901317. The aim of the present study was to evaluate whether effects of these drugs on β-cell function are specific and reliably linked to LXR activation. T0901317 and GW3965, widely used as specific LXR agonists, show rapid, non-genomic effects on stimulus-secretion coupling of mouse pancreatic β-cells at low µM concentrations. T0901317 lowered the cytosolic Ca2+ concentration, reduced or completely inhibited action potentials, and decreased insulin secretion. GW3965 exerted similar effects on insulin secretion. T0901317 affected the production of reactive oxygen species and ATP. The involvement of the classical nuclear LXRs in T0901317- and GW3965-mediated effects in β-cells could be ruled out using LXRα, LXRβ and double knockout mice. Our results strongly suggest that LXR agonists, that are considered to be specific for this receptor, interfere with mitochondrial metabolism and metabolism-independent processes in β-cells. Thus, it is indispensable to test novel LXR agonists accompanying to ongoing clinical trials for acute and chronic effects on cell function in cellular systems and/or animal models lacking classical LXRs.
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Affiliation(s)
- Jonas Maczewsky
- Institute of Pharmacy, Department of Pharmacology, University of Tübingen, Auf der Morgenstelle 8, 72076, Tübingen, Germany
| | - Julia Kaiser
- Institute of Pharmacy, Department of Pharmacology, University of Tübingen, Auf der Morgenstelle 8, 72076, Tübingen, Germany
| | - Peter Krippeit-Drews
- Institute of Pharmacy, Department of Pharmacology, University of Tübingen, Auf der Morgenstelle 8, 72076, Tübingen, Germany
| | - Gisela Drews
- Institute of Pharmacy, Department of Pharmacology, University of Tübingen, Auf der Morgenstelle 8, 72076, Tübingen, Germany.
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Sikimic J, Hoffmeister T, Gresch A, Kaiser J, Barthlen W, Wolke C, Wieland I, Lendeckel U, Krippeit-Drews P, Düfer M, Drews G. Possible New Strategies for the Treatment of Congenital Hyperinsulinism. Front Endocrinol (Lausanne) 2020; 11:545638. [PMID: 33193079 PMCID: PMC7653201 DOI: 10.3389/fendo.2020.545638] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 10/02/2020] [Indexed: 01/21/2023] Open
Abstract
OBJECTIVE Congenital hyperinsulinism (CHI) is a rare disease characterized by persistent hypoglycemia as a result of inappropriate insulin secretion, which can lead to irreversible neurological defects in infants. Poor efficacy and strong adverse effects of the current medications impede successful treatment. The aim of the study was to investigate new approaches to silence β-cells and thus attenuate insulin secretion. RESEARCH DESIGN AND METHODS In the scope of our research, we tested substances more selective and more potent than the gold standard diazoxide that also interact with neuroendocrine ATP-sensitive K+ (KATP) channels. Additionally, KATP channel-independent targets as Ca2+-activated K+ channels of intermediate conductance (KCa3.1) and L-type Ca2+ channels were investigated. Experiments were performed using human islet cell clusters isolated from tissue of CHI patients (histologically classified as pathological) and islet cell clusters obtained from C57BL/6N (WT) or SUR1 knockout (SUR1-/-) mice. The cytosolic Ca2+ concentration ([Ca2+]c) was used as a parameter for the pathway regulated by electrical activity and was determined by fura-2 fluorescence. The mitochondrial membrane potential (ΔΨ) was determined by rhodamine 123 fluorescence and single channel currents were measured by the patch-clamp technique. RESULTS The selective KATP channel opener NN414 (5 µM) diminished [Ca2+]c in isolated human CHI islet cell clusters and WT mouse islet cell clusters stimulated with 10 mM glucose. In islet cell clusters lacking functional KATP channels (SUR1-/-) the drug was without effect. VU0071063 (30 µM), another KATP channel opener considered to be selective, lowered [Ca2+]c in human CHI islet cell clusters. The compound was also effective in islet cell clusters from SUR1-/- mice, showing that [Ca2+]c is influenced by additional effects besides KATP channels. Contrasting to NN414, the drug depolarized ΔΨ in murine islet cell clusters pointing to severe interference with mitochondrial metabolism. An opener of KCa3.1 channels, DCEBIO (100 µM), significantly decreased [Ca2+]c in SUR1-/- and human CHI islet cell clusters. To target L-type Ca2+ channels we tested two already approved drugs, dextromethorphan (DXM) and simvastatin. DXM (100 µM) efficiently diminished [Ca2+]c in stimulated human CHI islet cell clusters as well as in stimulated SUR1-/- islet cell clusters. Similar effects on [Ca2+]c were observed in experiments with simvastatin (7.2 µM). CONCLUSIONS NN414 seems to provide a good alternative to the currently used KATP channel opener diazoxide. Targeting KCa3.1 channels by channel openers or L-type Ca2+ channels by DXM or simvastatin might be valuable approaches for treatment of CHI caused by mutations of KATP channels not sensitive to KATP channel openers.
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Affiliation(s)
- Jelena Sikimic
- Department of Pharmacology, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Theresa Hoffmeister
- Department of Pharmacology, Institute of Pharmaceutical and Medicinal Chemistry, University of Münster, Münster, Germany
| | - Anne Gresch
- Department of Pharmacology, Institute of Pharmaceutical and Medicinal Chemistry, University of Münster, Münster, Germany
| | - Julia Kaiser
- Department of Pharmacology, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Winfried Barthlen
- Department of Pediatric Surgery, University Medicine Greifswald, Greifswald, Germany
| | - Carmen Wolke
- Institute of Medical Biochemistry and Molecular Biology, University Medicine Greifswald, Greifswald, Germany
| | - Ilse Wieland
- Institute of Human Genetics, University Hospital Magdeburg, Magdeburg, Germany
| | - Uwe Lendeckel
- Institute of Medical Biochemistry and Molecular Biology, University Medicine Greifswald, Greifswald, Germany
| | - Peter Krippeit-Drews
- Department of Pharmacology, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
- *Correspondence: Peter Krippeit-Drews,
| | - Martina Düfer
- Department of Pharmacology, Institute of Pharmaceutical and Medicinal Chemistry, University of Münster, Münster, Germany
| | - Gisela Drews
- Department of Pharmacology, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
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Biological mechanisms and related natural modulators of liver X receptor in nonalcoholic fatty liver disease. Biomed Pharmacother 2019; 113:108778. [DOI: 10.1016/j.biopha.2019.108778] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 03/11/2019] [Accepted: 03/13/2019] [Indexed: 02/07/2023] Open
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Maczewsky J, Kaiser J, Gresch A, Gerst F, Düfer M, Krippeit-Drews P, Drews G. TGR5 Activation Promotes Stimulus-Secretion Coupling of Pancreatic β-Cells via a PKA-Dependent Pathway. Diabetes 2019; 68:324-336. [PMID: 30409782 DOI: 10.2337/db18-0315] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 10/31/2018] [Indexed: 11/13/2022]
Abstract
The Takeda-G-protein-receptor-5 (TGR5) mediates physiological actions of bile acids. Since it was shown that TGR5 is expressed in pancreatic tissue, a direct TGR5 activation in β-cells is currently postulated and discussed. The current study reveals that oleanolic acid (OLA) affects murine β-cell function by TGR5 activation. Both a Gαs inhibitor and an inhibitor of adenylyl cyclase (AC) prevented stimulating effects of OLA. Accordingly, OLA augmented the intracellular cAMP concentration. OLA and two well-established TGR5 agonists, RG239 and tauroursodeoxycholic acid (TUDCA), acutely promoted stimulus-secretion coupling (SSC). OLA reduced KATP current and elevated current through Ca2+ channels. Accordingly, in mouse and human β-cells, TGR5 ligands increased the cytosolic Ca2+ concentration by stimulating Ca2+ influx. Higher OLA concentrations evoked a dual reaction, probably due to activation of a counterregulating pathway. Protein kinase A (PKA) was identified as a downstream target of TGR5 activation. In contrast, inhibition of phospholipase C and phosphoinositide 3-kinase did not prevent stimulating effects of OLA. Involvement of exchange protein directly activated by cAMP 2 (Epac2) or farnesoid X receptor (FXR2) was ruled out by experiments with knockout mice. The proposed pathway was not influenced by local glucagon-like peptide 1 (GLP-1) secretion from α-cells, shown by experiments with MIN6 cells, and a GLP-1 receptor antagonist. In summary, these data clearly demonstrate that activation of TGR5 in β-cells stimulates insulin secretion via an AC/cAMP/PKA-dependent pathway, which is supposed to interfere with SSC by affecting KATP and Ca2+ currents and thus membrane potential.
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Affiliation(s)
- Jonas Maczewsky
- Institute of Pharmacy, Department of Pharmacology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Julia Kaiser
- Institute of Pharmacy, Department of Pharmacology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Anne Gresch
- Institute of Pharmaceutical and Medicinal Chemistry, Department of Pharmacology, University of Münster, Münster, Germany
| | - Felicia Gerst
- Institute for Diabetes Research and Metabolic Diseases, Helmholtz Center Munich, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Martina Düfer
- Institute of Pharmaceutical and Medicinal Chemistry, Department of Pharmacology, University of Münster, Münster, Germany
| | - Peter Krippeit-Drews
- Institute of Pharmacy, Department of Pharmacology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Gisela Drews
- Institute of Pharmacy, Department of Pharmacology, Eberhard Karls University of Tübingen, Tübingen, Germany
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Bauer C, Kaiser J, Sikimic J, Krippeit-Drews P, Düfer M, Drews G. ATP mediates a negative autocrine signal on stimulus-secretion coupling in mouse pancreatic β-cells. Endocrine 2019; 63:270-283. [PMID: 30229397 DOI: 10.1007/s12020-018-1731-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 08/20/2018] [Indexed: 02/07/2023]
Abstract
PURPOSE The role of ATP, which is secreted by pancreatic β-cells, is still a matter of debate. It has been postulated that extracellular ATP acts as a positive auto- or paracrine signal in β-cells amplifying insulin secretion. However, there is rising evidence that extracellular ATP may also mediate a negative signal. METHODS We evaluated whether extracellular ATP interferes with the Ca2+-mediated negative feedback mechanism that regulates oscillatory activity of β-cells. RESULTS To experimentally uncover the Ca2+-induced feedback we applied a high extracellular Ca2+ concentration. Under this condition ATP (100 µM) inhibited glucose-evoked oscillations of electrical activity and hyperpolarized the membrane potential. Furthermore, ATP acutely increased the interburst phase of Ca2+ oscillations and reduced the current through L-type Ca2+ channels. Accordingly, ATP (500 µM) decreased glucose-induced insulin secretion. The ATP effect was not mimicked by AMP, ADP, or adenosine. The use of specific agonists and antagonists and mice deficient of large conductance Ca2+-dependent K+ channels revealed that P2X, but not P2Y receptors, and Ca2+-dependent K+ channels are involved in the underlying signaling cascade induced by ATP. The effectiveness of ATP to interfere with parameters of stimulus-secretion coupling is markedly reduced at low extracellular Ca2+ concentration. CONCLUSION It is suggested that extracellular ATP which is co-secreted with insulin in a pulsatile manner during glucose-stimulated exocytosis provides a negative feedback signal driving β-cell oscillations in co-operation with Ca2+ and other signals.
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Affiliation(s)
- Cita Bauer
- Department of Pharmacology, Institute of Pharmacy, University of Tübingen, Auf der Morgenstelle 8, Tübingen, D-72076, Germany
| | - Julia Kaiser
- Department of Pharmacology, Institute of Pharmacy, University of Tübingen, Auf der Morgenstelle 8, Tübingen, D-72076, Germany
| | - Jelena Sikimic
- Department of Pharmacology, Institute of Pharmacy, University of Tübingen, Auf der Morgenstelle 8, Tübingen, D-72076, Germany
| | - Peter Krippeit-Drews
- Department of Pharmacology, Institute of Pharmacy, University of Tübingen, Auf der Morgenstelle 8, Tübingen, D-72076, Germany
| | - Martina Düfer
- Department of Pharmaceutical and Medicinal Chemistry, University of Münster, Corrensstraße 48, Münster, D-48149, Germany
| | - Gisela Drews
- Department of Pharmacology, Institute of Pharmacy, University of Tübingen, Auf der Morgenstelle 8, Tübingen, D-72076, Germany.
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