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Song Q, Ma H, Zhu L, Qi Z, Lan Z, Liu K, Zhang H, Wang K, Wang N. Upregulation of PTPN1 aggravates endotoxemia-induced cardiac dysfunction through inhibiting mitophagy. Int Immunopharmacol 2024; 126:111315. [PMID: 38043267 DOI: 10.1016/j.intimp.2023.111315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 11/26/2023] [Accepted: 11/27/2023] [Indexed: 12/05/2023]
Abstract
OBJECTIVES To investigate the role of protein tyrosine phosphatase non-receptor type 1 (PTPN1) in mitophagy during sepsis and its underlying mechanisms and determine the therapeutic potential of PTPN1 inhibitors in endotoxemia-induced cardiac dysfunction. METHODS A mouse model of endotoxemia was established by administering an intraperitoneal injection of lipopolysaccharide (LPS). The therapeutic effect of targeting PTPN1 was evaluated using its inhibitor Claramine (CLA). Mitochondrial structure and function as well as the expression of mitophagy-related proteins were evaluated. Rat H9c2 cardiomyocytes were exposed to mouse RAW264.7 macrophage-derived conditioned medium. Cryptotanshinone, a specific p-STAT3 (Y705) inhibitor, was used to confirm the role of STAT3 in PTPN1-mediated mitophagy following LPS exposure. Electrophoretic mobility shift and dual luciferase reporter assays were performed to discern the mechanisms by which STAT3 regulated the expression of PINK1 and PRKN. RESULTS CLA alleviated LPS-induced myocardial damage, cardiac dysfunction, and mitochondrial injury and dysfunction in the mouse heart. PTPN1 upregulation exacerbated LPS-induced mitochondrial injury and dysfunction in H9c2 cardiomyocytes, but inhibited LPS-induced mitophagy. LPS promoted the interaction between PTPN1 and STAT3 and reduced STAT3 phosphorylation at Tyr705 (Y705), which was required to inhibit mitophagy by PTPN1. Upon LPS stimulation, PTPN1 negatively regulated the transcription of PINK1 and PRKN through dephosphorylation of STAT3 at Y705. STAT3 regulated the transcription of PINK1 and PRKN by binding to STAT3-responsive elements in their promoters. CONCLUSION PTPN1 upregulation aggravates endotoxemia-induced cardiac dysfunction by impeding mitophagy through dephosphorylation of STAT3 at Y705 and negative regulation of PINK1 and PRKN transcription.
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Affiliation(s)
- Qixiang Song
- Department of Pathophysiology, School of Basic Medical Science, Central South University, 110 Xiangya Road, Changsha 410083, China; Key Laboratory of Sepsis Translational Medicine of Hunan, Central South University, 110 Xiangya Road, Changsha 410083, China
| | - Heng Ma
- Department of Pathophysiology, School of Basic Medical Science, Central South University, 110 Xiangya Road, Changsha 410083, China; Key Laboratory of Sepsis Translational Medicine of Hunan, Central South University, 110 Xiangya Road, Changsha 410083, China
| | - Lili Zhu
- Department of Pathophysiology, School of Basic Medical Science, Central South University, 110 Xiangya Road, Changsha 410083, China; Key Laboratory of Sepsis Translational Medicine of Hunan, Central South University, 110 Xiangya Road, Changsha 410083, China
| | - Zehong Qi
- Department of Pathophysiology, School of Basic Medical Science, Central South University, 110 Xiangya Road, Changsha 410083, China; Key Laboratory of Sepsis Translational Medicine of Hunan, Central South University, 110 Xiangya Road, Changsha 410083, China
| | - Zijun Lan
- Department of Pathophysiology, School of Basic Medical Science, Central South University, 110 Xiangya Road, Changsha 410083, China; Key Laboratory of Sepsis Translational Medicine of Hunan, Central South University, 110 Xiangya Road, Changsha 410083, China
| | - Ke Liu
- Department of Pathophysiology, School of Basic Medical Science, Central South University, 110 Xiangya Road, Changsha 410083, China; Key Laboratory of Sepsis Translational Medicine of Hunan, Central South University, 110 Xiangya Road, Changsha 410083, China
| | - Huali Zhang
- Department of Pathophysiology, School of Basic Medical Science, Central South University, 110 Xiangya Road, Changsha 410083, China; Key Laboratory of Sepsis Translational Medicine of Hunan, Central South University, 110 Xiangya Road, Changsha 410083, China
| | - KangKai Wang
- Department of Pathophysiology, School of Basic Medical Science, Central South University, 110 Xiangya Road, Changsha 410083, China; Key Laboratory of Sepsis Translational Medicine of Hunan, Central South University, 110 Xiangya Road, Changsha 410083, China.
| | - Nian Wang
- Department of Pathophysiology, School of Basic Medical Science, Central South University, 110 Xiangya Road, Changsha 410083, China; Key Laboratory of Sepsis Translational Medicine of Hunan, Central South University, 110 Xiangya Road, Changsha 410083, China.
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2
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Suh SB, Lee N, Kim J, Kim S, Jang S, Park JK, Lee K, Choi SY, Kwon HJ, Lee CH. Metformin ameliorates olanzapine-induced obesity and glucose intolerance by regulating hypothalamic inflammation and microglial activation in female mice. Front Pharmacol 2022; 13:906717. [PMID: 36313357 PMCID: PMC9596779 DOI: 10.3389/fphar.2022.906717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 09/26/2022] [Indexed: 11/16/2022] Open
Abstract
Olanzapine (OLZ), a widely used second-generation antipsychotic drug, is known to cause metabolic side effects, including diabetes and obesity. Interestingly, OLZ-induced metabolic side effects have been demonstrated to be more profound in females in human studies and animal models. Metformin (MET) is often used as a medication for the metabolic side effects of OLZ. However, the mechanisms underlying OLZ-induced metabolic disturbances and their treatment remain unclear. Recent evidence has suggested that hypothalamic inflammation is a key component of the pathophysiology of metabolic disorders. On this background, we conducted this study with the following three objectives: 1) to investigate whether OLZ can independently induce hypothalamic microgliosis; 2) to examine whether there are sex-dependent differences in OLZ-induced hypothalamic microgliosis; and 3) to examine whether MET affects hypothalamic microgliosis. We found that administration of OLZ for 5 days induced systemic glucose intolerance and hypothalamic microgliosis and inflammation. Of note, both hypothalamic microglial activation and systemic glucose intolerance were far more evident in female mice than in male mice. The administration of MET attenuated hypothalamic microglial activation and prevented OLZ-induced systemic glucose intolerance and hypothalamic leptin resistance. Minocycline, a tetracycline derivative that prevents microgliosis, showed similar results when centrally injected. Our findings reveal that OLZ induces metabolic disorders by causing hypothalamic inflammation and that this inflammation is alleviated by MET administration.
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Affiliation(s)
- Sang Bum Suh
- University of Ulsan College of Medicine, Seoul, South Korea
| | - Nayoung Lee
- Department of Biomedical Science, Hallym University, Chuncheon, South Korea
| | - Jaedeok Kim
- Department of Biomedical Science, Hallym University, Chuncheon, South Korea
| | - Saeha Kim
- Department of Biomedical Science, Hallym University, Chuncheon, South Korea
| | - Sooyeon Jang
- Department of Biomedical Science, Hallym University, Chuncheon, South Korea
| | - Jong Kook Park
- Department of Biomedical Science, Hallym University, Chuncheon, South Korea
| | - Keunwook Lee
- Department of Biomedical Science, Hallym University, Chuncheon, South Korea
| | - Soo Young Choi
- Department of Biomedical Science, Hallym University, Chuncheon, South Korea
| | - Hyung-Joo Kwon
- Department of Microbiology, College of Medicine, Hallym University, Chuncheon, South Korea
| | - Chan Hee Lee
- Department of Biomedical Science, Hallym University, Chuncheon, South Korea
- Program of Material Science for Medicine and Pharmaceutics, Hallym University, Chuncheon, South Korea
- *Correspondence: Chan Hee Lee,
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3
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Regulation of Nrf2 and NF-κB activities may contribute to the anti-inflammatory mechanism of xylopic acid. Inflammopharmacology 2022; 30:1835-1841. [PMID: 35260973 DOI: 10.1007/s10787-022-00950-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 02/15/2022] [Indexed: 12/12/2022]
Abstract
Xylopic acid (XA) is a kaurene diterpene which naturally exists in African plants such as Xylopia aethiopica. It has been established to exhibit acute and chronic anti-inflammatory activities from our earlier studies. This current work sets out to shed light on the potential molecular target(s) of xylopic acid. Selection of investigated targets (NF-κB, Nrf2 and PTP1B) was based on an unbiased approach, using the SPiDER in silico prediction tool, and a candidate approach, examining well-known anti-inflammatory targets. Reporter gene assays were used to test for altered NF-κB and Nrf2 activities in transfected HEK or CHO cells, respectively, and immunoblot and flow cytometric analyses examined protein expression of the Nrf2/NF-kB target genes HO-1 and VCAM-1 in HUVEC. An effect of XA on PTP1B activity assay was studied using an in vitro enzyme assay with recombinant human enzyme and pNPP as substrate as well as by looking at insulin receptor phosphorylation in HepG2 cells. XA at 30 µM significantly (p < 0.001) inhibited the NF-κB-dependent reporter gene expression and enhanced activation of Nrf2 in a concentration-dependent manner when compared to the control. XA also marginally increased HO-1 protein expression levels while expression of VCAM-1 was reduced to 70% in XA-treated endothelial cells. However, XA did not show any sign of inhibition of PTP1B or a related phosphatase. Our findings suggest that the anti-inflammatory mechanism of XA entails the inhibitory effect on NF-κB and an increased activity of Nrf2, accompanied by increased expression of HO-1 and reduced expression of VCAM-1.
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4
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AlaylioĞlu M, Dursun E, Yilmazer S, Ak DG. A Bridge Between in vitro and in vivo Studies in Neuroscience: Organotypic Brain Slice Cultures. ACTA ACUST UNITED AC 2020; 57:333-337. [PMID: 33354128 DOI: 10.29399/npa.26139] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 05/26/2020] [Indexed: 12/25/2022]
Abstract
In vitro and in vivo models are efficiently used systems in neuroscience research to study the brain in normal or pathological conditions. There are many advantages to these systems, yet they also have significant limitations. In vitro cell cultures offer the opportunity to investigate the cell basics or primary response of a cell population against any treatment. However, these models do not always predict in vivo behavior. In vivo animal studies constitute the most realistic platform for research and therapeutic approaches, yet they are laborious, open to secondary complications and painful or stressful for the animals from an ethical point of view. Organotypic brain slice cultures provide an in vivo-like environment since they maintain three-dimensional cytoarchitecture of the brain thus enable to study many cell types in one system and allow precise control of the microenvironment. In this review, we will focus on the history and key features of organotypic brain slice cultures as well as its preparation.
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Affiliation(s)
- Merve AlaylioĞlu
- Brain and Neurodegenerative Disorders Research Laboratory, Department of Medical Biology, Cerrahpaşa Faculty of Medicine, İstanbul University-Cerrahpaşa, İstanbul, Turkey
| | - Erdinç Dursun
- Brain and Neurodegenerative Disorders Research Laboratory, Department of Medical Biology, Cerrahpaşa Faculty of Medicine, İstanbul University-Cerrahpaşa, İstanbul, Turkey.,Department of Neuroscience, Institute of Neurological Sciences, İstanbul University-Cerrahpaşa, İstanbul, Turkey
| | - Selma Yilmazer
- Department of Medical Biology, School of Medicine, Altınbaş University, İstanbul, Turkey
| | - Duygu Gezen Ak
- Brain and Neurodegenerative Disorders Research Laboratory, Department of Medical Biology, Cerrahpaşa Faculty of Medicine, İstanbul University-Cerrahpaşa, İstanbul, Turkey
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5
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Lee S, Kim S, Kang HY, Lim HR, Kwon Y, Jo M, Jeon YM, Kim SR, Kim K, Ha CM, Lee S, Kim HJ. The overexpression of TDP-43 in astrocytes causes neurodegeneration via a PTP1B-mediated inflammatory response. J Neuroinflammation 2020; 17:299. [PMID: 33054766 PMCID: PMC7556969 DOI: 10.1186/s12974-020-01963-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 09/23/2020] [Indexed: 12/11/2022] Open
Abstract
Background Cytoplasmic inclusions of transactive response DNA binding protein of 43 kDa (TDP-43) in neurons and astrocytes are a feature of some neurodegenerative diseases, such as frontotemporal lobar degeneration with TDP-43 (FTLD-TDP) and amyotrophic lateral sclerosis (ALS). However, the role of TDP-43 in astrocyte pathology remains largely unknown. Methods To investigate whether TDP-43 overexpression in primary astrocytes could induce inflammation, we transfected primary astrocytes with plasmids encoding Gfp or TDP-43-Gfp. The inflammatory response and upregulation of PTP1B in transfected cells were examined using quantitative RT-PCR and immunoblot analysis. Neurotoxicity was analysed in a transwell coculture system of primary cortical neurons with astrocytes and cultured neurons treated with astrocyte-conditioned medium (ACM). We also examined the lifespan, performed climbing assays and analysed immunohistochemical data in pan-glial TDP-43-expressing flies in the presence or absence of a Ptp61f RNAi transgene. Results PTP1B inhibition suppressed TDP-43-induced secretion of inflammatory cytokines (interleukin 1 beta (IL-1β), interleukin 6 (IL-6) and tumour necrosis factor alpha (TNF-α)) in primary astrocytes. Using a neuron-astrocyte coculture system and astrocyte-conditioned media treatment, we demonstrated that PTP1B inhibition attenuated neuronal death and mitochondrial dysfunction caused by overexpression of TDP-43 in astrocytes. In addition, neuromuscular junction (NMJ) defects, a shortened lifespan, inflammation and climbing defects caused by pan-glial overexpression of TDP-43 were significantly rescued by downregulation of ptp61f (the Drosophila homologue of PTP1B) in flies. Conclusions These results indicate that PTP1B inhibition mitigates the neuronal toxicity caused by TDP-43-induced inflammation in mammalian astrocytes and Drosophila glial cells.
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Affiliation(s)
- Shinrye Lee
- Dementia Research Group, Korea Brain Research Institute (KBRI), Daegu, 41062, South Korea
| | - Seyeon Kim
- Dementia Research Group, Korea Brain Research Institute (KBRI), Daegu, 41062, South Korea.,Department of Brain & Cognitive Sciences, DGIST, Daegu, 42988, South Korea
| | - Ha-Young Kang
- Gwangju Center, Korea Basic Science Institute (KBSI), Gwangju, 61886, South Korea
| | - Hye Ryeong Lim
- Research Division and Brain Research Core Facilities, Korea Brain Research Institute (KBRI), Daegu, 41062, South Korea
| | - Younghwi Kwon
- Dementia Research Group, Korea Brain Research Institute (KBRI), Daegu, 41062, South Korea.,Department of Brain & Cognitive Sciences, DGIST, Daegu, 42988, South Korea
| | - Myungjin Jo
- Dementia Research Group, Korea Brain Research Institute (KBRI), Daegu, 41062, South Korea
| | - Yu-Mi Jeon
- Dementia Research Group, Korea Brain Research Institute (KBRI), Daegu, 41062, South Korea
| | - Sang Ryong Kim
- School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Institute of Life Science & Biotechnology, Kyungpook National University, Daegu, 41566, South Korea.,Brain Science and Engineering Institute, Kyungpook National University, Daegu, 41944, South Korea
| | - Kiyoung Kim
- Department of Medical Biotechnology, Soonchunhyang University, Asan, 31538, South Korea
| | - Chang Man Ha
- Research Division and Brain Research Core Facilities, Korea Brain Research Institute (KBRI), Daegu, 41062, South Korea
| | - Seongsoo Lee
- Gwangju Center, Korea Basic Science Institute (KBSI), Gwangju, 61886, South Korea.
| | - Hyung-Jun Kim
- Dementia Research Group, Korea Brain Research Institute (KBRI), Daegu, 41062, South Korea.
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6
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Hypothalamic glial cells isolated by MACS reveal that microglia and astrocytes induce hypothalamic inflammation via different processes under high-fat diet conditions. Neurochem Int 2020; 136:104733. [DOI: 10.1016/j.neuint.2020.104733] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 03/08/2020] [Accepted: 03/24/2020] [Indexed: 12/15/2022]
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7
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PTP1B promotes macrophage activation by regulating the NF-κB pathway in alcoholic liver injury. Toxicol Lett 2020; 319:11-21. [DOI: 10.1016/j.toxlet.2019.11.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 10/25/2019] [Accepted: 11/01/2019] [Indexed: 02/07/2023]
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8
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Liu B, Ou G, Chen Y, Zhang J. Inhibition of protein tyrosine phosphatase 1B protects against sevoflurane-induced neurotoxicity mediated by ER stress in developing brain. Brain Res Bull 2019; 146:28-39. [DOI: 10.1016/j.brainresbull.2018.12.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Revised: 11/14/2018] [Accepted: 12/12/2018] [Indexed: 10/27/2022]
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9
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DiNicolantonio JJ, McCarty M, OKeefe J. Does elevated bilirubin aid weight control by preventing development of hypothalamic leptin resistance? Open Heart 2019; 6:e000897. [PMID: 30997121 PMCID: PMC6443125 DOI: 10.1136/openhrt-2018-000897] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/04/2019] [Indexed: 12/16/2022] Open
Affiliation(s)
| | | | - James OKeefe
- Preventive Cardiology, Mid America Heart Institute, Kansas City, Missouri, USA
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10
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Debarba LK, Vechiato FMV, Veida-Silva H, Borges BC, Jamur MC, Antunes-Rodrigues J, Elias LLK. The role of TCPTP on leptin effects on astrocyte morphology. Mol Cell Endocrinol 2019; 482:62-69. [PMID: 30572001 DOI: 10.1016/j.mce.2018.12.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2018] [Revised: 11/25/2018] [Accepted: 12/15/2018] [Indexed: 12/19/2022]
Abstract
Leptin and LPS has been implicated in the development of hypothalamic astrogliosis in rodents. Astrocytes, which are interconnected by gap junction proteins, have emerged as important players in the control of energy homeostasis exerted by the hypothalamus. To investigate the hypothesis of action of T-cell protein tyrosine phosphatase (TCPTP) on the astrocyte morphology, astrocytes from the hypothalamus of one-day-old rats were stimulated with leptin and LPS (used as a positive control). Leptin and LPS induced a marked increase in astrocyte size, an increase in Ptpn2 (TCPTP gene) and gap junction alpha-1 protein, - Gja1 (connexin 43 - CX43 gene) mRNA expression and a decrease in gap junction protein, alpha 6 - Gja6 (CX30 gene) mRNA expression. Remarkably, these effects on astrocytes morphology and connexins were prevented by Ptpn2 siRNA. Astrocytes are known to produce cytokines; here we show that TCPTP acts as an important regulator of the cytokines and it possesses a reciprocal interplay with protein tyrosine phosphatase 1B (PTP1B). Our findings demonstrate that leptin and LPS alter astrocyte morphology by increasing TCPTP, which in turn modulates connexin 30 (CX30) and connexin 43 (CX43) expression. TCPTP and PTP1B seem to act in the regulation of cytokine production in astrocytes.
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Affiliation(s)
- Lucas Kniess Debarba
- Department of Physiology, Ribeirao Preto Medical School, University of Sao Paulo, Sao Paulo, Brazil.
| | | | - Hellen Veida-Silva
- Department of Physiology, Ribeirao Preto Medical School, University of Sao Paulo, Sao Paulo, Brazil
| | - Beatriz C Borges
- Department of Physiology, Ribeirao Preto Medical School, University of Sao Paulo, Sao Paulo, Brazil
| | - Maria Célia Jamur
- Department of Cell and Molecular Biology and Pathogenic Bioagents, Ribeirao Preto Medical School, University of Sao Paulo, Sao Paulo, 14049-900, Brazil
| | - José Antunes-Rodrigues
- Department of Physiology, Ribeirao Preto Medical School, University of Sao Paulo, Sao Paulo, Brazil
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11
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Clemenzi MN, Wellhauser L, Aljghami ME, Belsham DD. Tumour necrosis factor α induces neuroinflammation and insulin resistance in immortalised hypothalamic neurones through independent pathways. J Neuroendocrinol 2019; 31:e12678. [PMID: 30582235 DOI: 10.1111/jne.12678] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Revised: 11/26/2018] [Accepted: 12/05/2018] [Indexed: 12/27/2022]
Abstract
The links between obesity, inflammation and insulin resistance, which are all key characteristics of type 2 diabetes mellitus, are yet to be delineated in the brain. One of the key neuroinflammatory proteins detected in the hypothalamus with over-nutrition is tumour necrosis factor (TNF)α. Using immortalised embryonic rat and mouse hypothalamic cell lines (rHypoE-7 and mHypoE-46) that express orexigenic neuropeptide Y and agouti-related peptide, we investigated changes in insulin signalling and inflammatory gene marker mRNA expression after TNFα exposure. A quantitative polymerase chain reaction array of 84 inflammatory markers (cytokines, chemokines and receptors) demonstrated an increase in the expression of multiple genes encoding inflammatory markers upon exposure to 100 ng mL-1 TNFα for 4 hours. Furthermore, neurones pre-exposed to TNFα (50 ng mL-1 ) for 6 or 16 hours exhibited a significant reduction in phosphorylated Akt compared to control after insulin treatment, indicating the attenuation of insulin signalling. mRNA expression of insulin signalling-related genes was also decreased with exposure to TNFα. TNFα significantly increased mRNA expression of IκBα, Tnfrsf1a and IL6 at 4 and 24 hours, activating a pro-inflammatory state. An inhibitor study using an inhibitor of nuclear factor kappa B kinase subunit β (IKK-β) inhibitor, PS1145, demonstrated that TNFα-induced neuroinflammatory marker expression occurs through the IKK-β/nuclear factor-kappa B pathway, whereas oleate, a monounsaturated fatty acid, had no effect on inflammatory markers. To test the efficacy of anti-inflammatory treatment to reverse insulin resistance, neurones were treated with TNFα and PS1145, which did not significantly restore the TNFα-induced changes in cellular insulin sensitivity, indicating that an alternative pathway may be involved. In conclusion, exposure to the inflammatory cytokine TNFα causes cellular insulin resistance and inflammation marker expression in the rHypoE-7 and mHypoE-46 neurones, consistent with effects seen with TNFα in peripheral tissues. It also mimics insulin- and palmitate-induced insulin resistance in hypothalamic neurones. The present study provides further evidence that altered central energy metabolism may be caused by obesity-induced cytokine expression.
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Affiliation(s)
| | - Leigh Wellhauser
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Makram E Aljghami
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Denise D Belsham
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Department of Obstetrics and Gynaecology, University of Toronto, Toronto, ON, Canada
- Department of Medicine, University of Toronto, Toronto, ON, Canada
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Abstract
The hypothalamus is the brain region responsible for the maintenance of energetic homeostasis. The regulation of this process arises from the ability of the hypothalamus to orchestrate complex physiological responses such as food intake and energy expenditure, circadian rhythm, stress response, and fertility. Metabolic alterations such as obesity can compromise these hypothalamic regulatory functions. Alterations in circadian rhythm, stress response, and fertility further contribute to aggravate the metabolic dysfunction of obesity and contribute to the development of chronic disorders such as depression and infertility.At cellular level, obesity caused by overnutrition can damage the hypothalamus promoting inflammation and impairing hypothalamic neurogenesis. Furthermore, hypothalamic neurons suffer apoptosis and impairment in synaptic plasticity that can compromise the proper functioning of the hypothalamus. Several factors contribute to these phenomena such as ER stress, oxidative stress, and impairments in autophagy. All these observations occur at the same time and it is still difficult to discern whether inflammatory processes are the main drivers of these cellular dysfunctions or if the hypothalamic hormone resistance (insulin, leptin, and ghrelin) can be pinpointed as the source of several of these events.Understanding the mechanisms that underlie the pathophysiology of obesity in the hypothalamus is crucial for the development of strategies that can prevent or attenuate the deleterious effects of obesity.
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13
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Méndez-García LA, Trejo-Millán F, Martínez-Reyes CP, Manjarrez-Reyna AN, Esquivel-Velázquez M, Melendez-Mier G, Islas-Andrade S, Rojas-Bernabé A, Kzhyshkowska J, Escobedo G. Infliximab ameliorates tumor necrosis factor-alpha-induced insulin resistance by attenuating PTP1B activation in 3T3L1 adipocytes in vitro. Scand J Immunol 2018; 88:e12716. [PMID: 30260514 DOI: 10.1111/sji.12716] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 08/27/2018] [Accepted: 09/02/2018] [Indexed: 02/06/2023]
Abstract
Insulin resistance is the inability to respond to insulin and is considered a key pathophysiological factor in the development of type 2 diabetes. Tumor necrosis factor-alpha (TNF-alpha) can directly contribute to insulin resistance by disrupting the insulin signalling pathway via protein-tyrosine phosphatase 1B (PTP1B) activation, especially in adipocytes. Infliximab (Remicade® ) is a TNF-alpha-neutralizing antibody that has not been fully studied in insulin resistance. We investigated the effect of infliximab on TNF-alpha-induced insulin resistance in 3T3L1 adipocytes in vitro, and examined the possible molecular mechanisms involved. Once differentiated, adipocytes were cultured with 5 mmol L-1 2-deoxy-D-glucose-3 H and stimulated twice with 2 μmol L-1 insulin, in the presence or absence of 5 ng/mL TNF-alpha and/or 10 ng/mL infliximab. Glucose uptake was measured every 20 minutes for 2 hour, and phosphorylated forms of insulin receptor (IR), insulin receptor substrate-2 (IRS-2), protein kinase B (AKT) and PTP1B were determined by Western blotting. TNF-alpha-treated adipocytes showed a significant 64% decrease in insulin-stimulated glucose uptake as compared with control cells, whereas infliximab reversed TNF-alpha actions by significantly improving glucose incorporation. Although IR phosphorylation remained unaltered, TNF-alpha was able to increase PTP1B activation and decrease phosphorylation of IRS-2 and AKT. Notably, infliximab restored phosphorylation of IRS-2 and AKT by attenuating PTP1B activation. This work demonstrates for the first time that infliximab ameliorates TNF-alpha-induced insulin resistance in 3T3L1 adipocytes in vitro by restoring the insulin signalling pathway via PTP1B inhibition. Further clinical research is needed to determine the potential benefit of using infliximab for treating insulin resistance in patients.
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Affiliation(s)
- Lucia A Méndez-García
- Laboratory for Proteomics and Metabolomics, Research Division, General Hospital of Mexico "Dr. Eduardo Liceaga", Mexico City, Mexico
| | - Fernanda Trejo-Millán
- Laboratory for Proteomics and Metabolomics, Research Division, General Hospital of Mexico "Dr. Eduardo Liceaga", Mexico City, Mexico
| | - Camilo P Martínez-Reyes
- Laboratory for Proteomics and Metabolomics, Research Division, General Hospital of Mexico "Dr. Eduardo Liceaga", Mexico City, Mexico
| | - Aarón N Manjarrez-Reyna
- Laboratory for Proteomics and Metabolomics, Research Division, General Hospital of Mexico "Dr. Eduardo Liceaga", Mexico City, Mexico
| | - Marcela Esquivel-Velázquez
- Laboratory for Proteomics and Metabolomics, Research Division, General Hospital of Mexico "Dr. Eduardo Liceaga", Mexico City, Mexico
| | - Guillermo Melendez-Mier
- Laboratory for Proteomics and Metabolomics, Research Division, General Hospital of Mexico "Dr. Eduardo Liceaga", Mexico City, Mexico
| | - Sergio Islas-Andrade
- Laboratory for Proteomics and Metabolomics, Research Division, General Hospital of Mexico "Dr. Eduardo Liceaga", Mexico City, Mexico
| | - Araceli Rojas-Bernabé
- Research Unit for Experimental Medicine, School of Medicine, National Autonomous University of Mexico, Mexico City, Mexico
| | - Julia Kzhyshkowska
- Department of Innate Immunity and Tolerance, Institute of Transfusion Medicine and Immunology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Galileo Escobedo
- Laboratory for Proteomics and Metabolomics, Research Division, General Hospital of Mexico "Dr. Eduardo Liceaga", Mexico City, Mexico
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14
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Central s-resistin deficiency ameliorates hypothalamic inflammation and increases whole body insulin sensitivity. Sci Rep 2018; 8:3921. [PMID: 29500410 PMCID: PMC5834531 DOI: 10.1038/s41598-018-22255-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 11/28/2017] [Indexed: 11/23/2022] Open
Abstract
S-resistin, a non-secretable resistin isoform, acts as an intracrine factor that regulates adipocyte maduration, inflammatory and insulin response in 3T3-L1 cells. However, its intracellular function in vivo is still unknown. In this study, we analyze the central role of s-resistin, decreasing its hypothalamic expression using an intracerebroventricular injection of lentiviral RNAi. The data present herein support an improvement in the hypothalamic leptin and insulin signaling pathway upon s-resistin downregulation. Furthermore, hypothalamic levels of pro-inflammatory markers decrease, meanwhile those of the anti-inflammatory cytokine IL-10 increases. Interestingly, peripheral NEFA decreases alike circulating leptin and resistin levels. These data demonstrate that hypothalamic s-resistin controls fuel mobilization and adipokines secretion. Importantly, central s-resistin downregulation improves systemic insulin sensitivity, as demonstrated after an IPGTT. Interestingly, our data also indicate that s-resistin downregulation could improve hypothalamic inflammation in aged Wistar rats. Altogether, our findings suggest that hypothalamic s-resistin seems to be a key regulator of the brain-fat axis which links inflammation with metabolic homeostasis.
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Ma C, Yu H, Xiao Y, Wang H. Momordica charantia extracts ameliorate insulin resistance by regulating the expression of SOCS-3 and JNK in type 2 diabetes mellitus rats. PHARMACEUTICAL BIOLOGY 2017; 55:2170-2177. [PMID: 29110587 PMCID: PMC6130557 DOI: 10.1080/13880209.2017.1396350] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 09/21/2017] [Accepted: 10/18/2017] [Indexed: 05/31/2023]
Abstract
CONTEXT Momordica charantia L. (Cucurbitaceae) has long been widely used as a traditional remedy for diabetes mellitus in some countries. However, detailed antidiabetic mechanisms are largely unknown. OBJECTIVES This study clarified the ameliorating effects of M. charantia ethanol extracts (MCE) on the insulin resistance in type 2 diabetes mellitus (T2DM) rats. MATERIALS AND METHODS T2DM rat model was established by high-fat diet and streptozotocin (STZ) injection. Diabetic rats were randomized into five groups: the model control group (n = 8) (common diet), the high-fat diet metformin (50 mg/kg/d), and the three-dose MCE (100, 200, and 400 mg/kg/d) groups (n = 8 each). After 8 weeks, the fasting serum glucose, insulin, TNF-α, and IL-6 were measured, and the relevant factors of glucose and insulin were monitored by glycogen dyeing, RT-PCR, and western blot, respectively. RESULTS The 8-week treatment of 400 mg/kg MCE significantly lowered body weight (330.1 versus 365.9 g), serum glucose (7.41 versus 16.63 mmol/L), insulin (12.06 versus 15.89 mIU/L), TNF-α (52.72 versus 81.83 ng/L), and IL-6 (104.81 versus 135.74 ng/L) in comparison with those of the diabetic control group (p < 0.05). It was the same for skeletal muscle glucose transporter 4 (GLUT-4) protein, and glycogen level, suppressor of cytokine signaling-3 (SOCS-3), c-Jun N-terminal kinase (JNK), and Akt expression at both protein and mRNA levels in liver (p < 0.05). CONCLUSIONS MCE can ameliorate insulin resistance in T2DM rats. This effect may be related to the regulation of mRNA and protein levels of SOCS-3 and JNK.
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Affiliation(s)
- Chunyu Ma
- Department of Laboratory Diagnosis, Jinzhou Medical University, Jinzhou, PR China
| | - Hongyu Yu
- Department of Basic Nursing, Jinzhou Medical University, Jinzhou, PR China
| | - Ying Xiao
- Department of Laboratory Diagnosis, Jinzhou Medical University, Jinzhou, PR China
| | - Huijiao Wang
- Department of Laboratory Diagnosis, Jinzhou Medical University, Jinzhou, PR China
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Sugiyama M, Banno R, Mizoguchi A, Tominaga T, Tsunekawa T, Onoue T, Hagiwara D, Ito Y, Morishita Y, Iwama S, Goto M, Suga H, Arima H. PTP1B deficiency improves hypothalamic insulin sensitivity resulting in the attenuation of AgRP mRNA expression under high-fat diet conditions. Biochem Biophys Res Commun 2017; 488:116-121. [PMID: 28479249 DOI: 10.1016/j.bbrc.2017.05.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 05/03/2017] [Indexed: 11/19/2022]
Abstract
Hypothalamic insulin receptor signaling regulates energy balance and glucose homeostasis via agouti-related protein (AgRP). While protein tyrosine phosphatase 1B (PTP1B) is classically known to be a negative regulator of peripheral insulin signaling by dephosphorylating both insulin receptor β (IRβ) and insulin receptor substrate, the role of PTP1B in hypothalamic insulin signaling remains to be fully elucidated. In the present study, we investigated the role of PTP1B in hypothalamic insulin signaling using PTP1B deficient (KO) mice in vivo and ex vivo. For the in vivo study, hypothalamic insulin resistance induced by a high-fat diet (HFD) improved in KO mice compared to wild-type (WT) mice. Hypothalamic AgRP mRNA expression levels were also significantly decreased in KO mice independent of body weight changes. In an ex vivo study using hypothalamic organotypic cultures, insulin treatment significantly increased the phosphorylation of both IRβ and Akt in the hypothalamus of KO mice compared to WT mice, and also significantly decreased AgRP mRNA expression levels in KO mice. While incubation with inhibitors of phosphatidylinositol-3 kinase (PI3K) had no effect on basal levels of Akt phosphorylation, these suppressed insulin induction of Akt phosphorylation to almost basal levels in WT and KO mice. The inhibition of the PI3K-Akt pathway blocked the downregulation of AgRP mRNA expression in KO mice treated with insulin. These data suggest that PTP1B acts on the hypothalamic insulin signaling via the PI3K-Akt pathway. Together, our results suggest a deficiency of PTP1B improves hypothalamic insulin sensitivity resulting in the attenuation of AgRP mRNA expression under HFD conditions.
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Affiliation(s)
- Mariko Sugiyama
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Ryoichi Banno
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
| | - Akira Mizoguchi
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Takashi Tominaga
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Taku Tsunekawa
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Takeshi Onoue
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Daisuke Hagiwara
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Yoshihiro Ito
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Yoshiaki Morishita
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Shintaro Iwama
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan; Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya 464-8601, Japan
| | - Motomitsu Goto
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Hidetaka Suga
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Hiroshi Arima
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
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17
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Mendes NF, Castro G, Guadagnini D, Tobar N, Cognuck SQ, Elias LLK, Boer PA, Prada PO. Knocking down amygdalar PTP1B in diet-induced obese rats improves insulin signaling/action, decreases adiposity and may alter anxiety behavior. Metabolism 2017; 70:1-11. [PMID: 28403933 DOI: 10.1016/j.metabol.2017.01.029] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 01/03/2017] [Accepted: 01/27/2017] [Indexed: 11/18/2022]
Abstract
OBJECTIVE Protein tyrosine phosphatase 1B (PTP1B) has been extensively implicated in the regulation of body weight, food intake, and energy expenditure. The role of PTP1B appears to be cell and brain region dependent. RESULTS Herein, we demonstrated that chronic high-fat feeding enhanced PTP1B expression in the central nucleus of the amygdala (CeA) of rats compared to rats on chow. Knocking down PTP1B with oligonucleotide antisense (ASO) decreased its expression and was sufficient to improve the anorexigenic effect of insulin through IR/Akt signaling in the CeA. ASO treatment reduces body weight, fat mass, serum leptin levels, and food intake and also increases energy expenditure, without altering ambulatory activity. These changes were explained, at least in part, by the improvement of insulin sensitivity in the CeA, decreasing NPY and enhancing oxytocin expression. There was a slight decline in fasting blood glucose and serum insulin levels possibly due to leanness in rats treated with ASO. Surprisingly, the elevated plus maze test revealed an anxiolytic behavior after reduction of PTP1B in the CeA. CONCLUSIONS Thus, the present study highlights the deleterious role that the amygdalar PTP1B has on energy homeostasis in obesity states. The reduction of PTP1B in the CeA may be a strategy for the treatment of obesity, insulin resistance and anxiety disorders.
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Affiliation(s)
| | - Gisele Castro
- Department of Internal Medicine, State University of Campinas, UNICAMP, Brazil
| | - Dioze Guadagnini
- Department of Internal Medicine, State University of Campinas, UNICAMP, Brazil
| | - Natalia Tobar
- Department of Internal Medicine, State University of Campinas, UNICAMP, Brazil
| | - Susana Quiros Cognuck
- Department of Physiology, School of Medicine of Ribeirao Preto, University of Sao Paulo, USP, Brazil
| | | | - Patricia Aline Boer
- Department of Internal Medicine, State University of Campinas, UNICAMP, Brazil
| | - Patricia Oliveira Prada
- School of Applied Sciences, State University of Campinas, UNICAMP, Brazil; Department of Internal Medicine, State University of Campinas, UNICAMP, Brazil.
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18
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Vieira MNN, Lyra E Silva NM, Ferreira ST, De Felice FG. Protein Tyrosine Phosphatase 1B (PTP1B): A Potential Target for Alzheimer's Therapy? Front Aging Neurosci 2017; 9:7. [PMID: 28197094 PMCID: PMC5281585 DOI: 10.3389/fnagi.2017.00007] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 01/12/2017] [Indexed: 01/21/2023] Open
Abstract
Despite significant advances in current understanding of mechanisms of pathogenesis in Alzheimer's disease (AD), attempts at drug development based on those discoveries have failed to translate into effective, disease-modifying therapies. AD is a complex and multifactorial disease comprising a range of aberrant cellular/molecular processes taking part in different cell types and brain regions. As a consequence, therapeutics for AD should be able to block or compensate multiple abnormal pathological events. Here, we examine recent evidence that inhibition of protein tyrosine phosphatase 1B (PTP1B) may represent a promising strategy to combat a variety of AD-related detrimental processes. Besides its well described role as a negative regulator of insulin and leptin signaling, PTB1B recently emerged as a modulator of various other processes in the central nervous system (CNS) that are also implicated in AD. These include signaling pathways germane to learning and memory, regulation of synapse dynamics, endoplasmic reticulum (ER) stress and microglia-mediated neuroinflammation. We propose that PTP1B inhibition may represent an attractive and yet unexplored therapeutic approach to correct aberrant signaling pathways linked to AD.
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Affiliation(s)
- Marcelo N N Vieira
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de JaneiroRio de Janeiro, Brazil; Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de JaneiroRio de Janeiro, Brazil
| | - Natalia M Lyra E Silva
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro Rio de Janeiro, Brazil
| | - Sergio T Ferreira
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de JaneiroRio de Janeiro, Brazil; Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de JaneiroRio de Janeiro, Brazil
| | - Fernanda G De Felice
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de JaneiroRio de Janeiro, Brazil; Centre for Neuroscience Studies, Department of Biomedical and Molecular Sciences, Queen's UniversityKingston, ON, Canada
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Tsunekawa T, Banno R, Mizoguchi A, Sugiyama M, Tominaga T, Onoue T, Hagiwara D, Ito Y, Iwama S, Goto M, Suga H, Sugimura Y, Arima H. Deficiency of PTP1B Attenuates Hypothalamic Inflammation via Activation of the JAK2-STAT3 Pathway in Microglia. EBioMedicine 2017; 16:172-183. [PMID: 28094236 PMCID: PMC5474442 DOI: 10.1016/j.ebiom.2017.01.007] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 01/05/2017] [Accepted: 01/05/2017] [Indexed: 02/06/2023] Open
Abstract
Protein tyrosine phosphatase 1B (PTP1B) regulates leptin signaling in hypothalamic neurons via the JAK2-STAT3 pathway. PTP1B has also been implicated in the regulation of inflammation in the periphery. However, the role of PTP1B in hypothalamic inflammation, which is induced by a high-fat diet (HFD), remains to be elucidated. Here, we showed that STAT3 phosphorylation (p-STAT3) was increased in microglia in the hypothalamic arcuate nucleus of PTP1B knock-out mice (KO) on a HFD, accompanied by decreased Tnf and increased Il10 mRNA expression in the hypothalamus compared to wild-type mice (WT). In hypothalamic organotypic cultures, incubation with TNFα led to increased p-STAT3, accompanied by decreased Tnf and increased Il10 mRNA expression, in KO compared to WT. Incubation with p-STAT3 inhibitors or microglial depletion eliminated the differences in inflammation between genotypes. These data indicate an important role of JAK2-STAT3 signaling negatively regulated by PTP1B in microglia, which attenuates hypothalamic inflammation under HFD conditions.
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Affiliation(s)
- Taku Tsunekawa
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
| | - Ryoichi Banno
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
| | - Akira Mizoguchi
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
| | - Mariko Sugiyama
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
| | - Takashi Tominaga
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
| | - Takeshi Onoue
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
| | - Daisuke Hagiwara
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
| | - Yoshihiro Ito
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
| | - Shintaro Iwama
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan; Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya 464-8601, Japan.
| | - Motomitsu Goto
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
| | - Hidetaka Suga
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
| | - Yoshihisa Sugimura
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
| | - Hiroshi Arima
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
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20
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Ottanà R, Paoli P, Naß A, Lori G, Cardile V, Adornato I, Rotondo A, Graziano ACE, Wolber G, Maccari R. Discovery of 4-[(5-arylidene-4-oxothiazolidin-3-yl)methyl]benzoic acid derivatives active as novel potent allosteric inhibitors of protein tyrosine phosphatase 1B: In silico studies and in vitro evaluation as insulinomimetic and anti-inflammatory agents. Eur J Med Chem 2016; 127:840-858. [PMID: 27842892 DOI: 10.1016/j.ejmech.2016.10.063] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Revised: 09/26/2016] [Accepted: 10/30/2016] [Indexed: 12/15/2022]
Abstract
New 4-{[5-arylidene-2-(4-fluorophenylimino)-4-oxothiazolidin-3-yl]methyl}benzoic acids (5) and 2-thioxo-4-thiazolidinone analogues (6) were synthesised as a part of a continuing search for new inhibitors of protein tyrosine phosphatase 1B (PTP1B), an enzyme which is implicated in metabolic disorders and inflammatory signaling. Most of the tested compounds were shown to be potent PTP1B inhibitors. Moreover, their inhibition mechanism was markedly influenced by the substituents in the positions 2 and 5, as kinetic studies indicated. Docking experiments suggested that certain derivatives 5 and 6 may efficiently fit into an allosteric site positioned between the β-sheet including Leu71 and Lys73 and a lipophilic pocket closed by the loop consisting of Pro210 to Leu 204. In cellular assays, several of these new 4-thiazolidinone derivatives showed insulinomimetic and anti-inflammatory properties. Out of them, compound 5b exhibited the most promising profile, being able to promote the activation of both insulin receptor and downstream Akt protein as well as to increase 2-deoxyglucose cellular uptake. Interestingly, compound 5b was also able to interrupt critical events in inflammatory signaling.
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Affiliation(s)
- Rosaria Ottanà
- Department of Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, University of Messina, Polo Universitario dell'Annunziata, Viale SS. Annunziata, 98168 Messina, Italy
| | - Paolo Paoli
- Department of Scienze Biomediche Sperimentali e Cliniche, Sezione di Scienze Biochimiche, University of Firenze, Viale Morgagni 50, 50134 Firenze, Italy
| | - Alexandra Naß
- Institute of Pharmacy, Computer-Aided Molecular Design, Freie Universitaet Berlin, Koenigin-Luisestr. 2+4, 14195 Berlin, Germany
| | - Giulia Lori
- Department of Scienze Biomediche Sperimentali e Cliniche, Sezione di Scienze Biochimiche, University of Firenze, Viale Morgagni 50, 50134 Firenze, Italy
| | - Venera Cardile
- Department of Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, Via S. Sofia, 64, 95125 Catania, Italy
| | - Ilenia Adornato
- Department of Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, University of Messina, Polo Universitario dell'Annunziata, Viale SS. Annunziata, 98168 Messina, Italy
| | - Archimede Rotondo
- Department of Scienze Biomediche, Odontoiatriche e delle Immagini Morfologiche e Funzionali, Università degli Studi di Messina - sez. SASTAS - Polo Universitario dell'Annunziata, Viale SS. Annunziata, 98168 Messina, Italy
| | - Adriana Carol Eleonora Graziano
- Department of Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, Via S. Sofia, 64, 95125 Catania, Italy
| | - Gerhard Wolber
- Institute of Pharmacy, Computer-Aided Molecular Design, Freie Universitaet Berlin, Koenigin-Luisestr. 2+4, 14195 Berlin, Germany
| | - Rosanna Maccari
- Department of Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, University of Messina, Polo Universitario dell'Annunziata, Viale SS. Annunziata, 98168 Messina, Italy.
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Song GJ, Jung M, Kim JH, Park H, Rahman MH, Zhang S, Zhang ZY, Park DH, Kook H, Lee IK, Suk K. A novel role for protein tyrosine phosphatase 1B as a positive regulator of neuroinflammation. J Neuroinflammation 2016; 13:86. [PMID: 27095436 PMCID: PMC4837589 DOI: 10.1186/s12974-016-0545-3] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 04/11/2016] [Indexed: 01/28/2023] Open
Abstract
Background Protein tyrosine phosphatase 1B (PTP1B) is a member of the non-transmembrane phosphotyrosine phosphatase family. Recently, PTP1B has been proposed to be a novel target of anti-cancer and anti-diabetic drugs. However, the role of PTP1B in the central nervous system is not clearly understood. Therefore, in this study, we sought to define PTP1B’s role in brain inflammation. Methods PTP1B messenger RNA (mRNA) and protein expression levels were examined in mouse brain and microglial cells after LPS treatment using RT-PCR and western blotting. Pharmacological inhibitors of PTP1B, NF-κB, and Src kinase were used to analyze these signal transduction pathways in microglia. A Griess reaction protocol was used to determine nitric oxide (NO) concentrations in primary microglia cultures and microglial cell lines. Proinflammatory cytokine production was measured by RT-PCR. Western blotting was used to assess Src phosphorylation levels. Immunostaining for Iba-1 was used to determine microglial activation in the mouse brain. Results PTP1B expression levels were significantly increased in the brain 24 h after LPS injection, suggesting a functional role for PTP1B in brain inflammation. Microglial cells overexpressing PTP1B exhibited an enhanced production of NO and gene expression levels of TNF-α, iNOS, and IL-6 following LPS exposure, suggesting that PTP1B potentiates the microglial proinflammatory response. To confirm the role of PTP1B in neuroinflammation, we employed a highly potent and selective inhibitor of PTP1B (PTP1Bi). In LPS- or TNF-α-stimulated microglial cells, in vitro blockade of PTP1B activity using PTP1Bi markedly attenuated NO production. PTP1Bi also suppressed the expression levels of iNOS, COX-2, TNF-α, and IL-1β. PTP1B activated Src by dephosphorylating the Src protein at a negative regulatory site. PTP1B-mediated Src activation led to an enhanced proinflammatory response in the microglial cells. An intracerebroventricular injection of PTP1Bi significantly attenuated microglial activation in the hippocampus and cortex of LPS-injected mice compared to vehicle-injected mice. The gene expression levels of proinflammatory cytokines were also significantly suppressed in the brain by a PTP1Bi injection. Together, these data suggest that PTP1Bi has an anti-inflammatory effect in a mouse model of neuroinflammation. Conclusions This study demonstrates that PTP1B is an important positive regulator of neuroinflammation and is a promising therapeutic target for neuroinflammatory and neurodegenerative diseases. Electronic supplementary material The online version of this article (doi:10.1186/s12974-016-0545-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Gyun Jee Song
- Department of Pharmacology, Brain Science and Engineering Institute, BK21 Plus KNU Biomedical Convergence Program, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | - Myungsu Jung
- Department of Pharmacology, Brain Science and Engineering Institute, BK21 Plus KNU Biomedical Convergence Program, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | - Jong-Heon Kim
- Department of Pharmacology, Brain Science and Engineering Institute, BK21 Plus KNU Biomedical Convergence Program, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | - Hana Park
- Department of Pharmacology, Brain Science and Engineering Institute, BK21 Plus KNU Biomedical Convergence Program, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | - Md Habibur Rahman
- Department of Pharmacology, Brain Science and Engineering Institute, BK21 Plus KNU Biomedical Convergence Program, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | - Sheng Zhang
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, 47907, USA
| | - Zhong-Yin Zhang
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, 47907, USA
| | - Dong Ho Park
- Department of Ophthalmology, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | - Hyun Kook
- Department of Pharmacology, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - In-Kyu Lee
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | - Kyoungho Suk
- Department of Pharmacology, Brain Science and Engineering Institute, BK21 Plus KNU Biomedical Convergence Program, Kyungpook National University School of Medicine, Daegu, Republic of Korea.
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22
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Reactive oxygen species mediate insulin signal transduction in mouse hypothalamus. Neurosci Lett 2016; 619:1-7. [PMID: 26968348 DOI: 10.1016/j.neulet.2016.03.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 02/29/2016] [Accepted: 03/07/2016] [Indexed: 01/26/2023]
Abstract
In the hypothalamus, several reports have implied that ROS mediate physiological effects of insulin. In this study, we investigated the mechanisms of insulin-induced ROS production and the effect of ROS on insulin signal transduction in mouse hypothalamic organotypic cultures. Insulin increased intracellular ROS, which were suppressed by NADPH oxidase inhibitor. H2O2 increased phospho-insulin receptor β (p-IRβ) and phospho-Akt (p-Akt) levels. Insulin-induced increases in p-IRβ and p-Akt levels were attenuated by ROS scavenger or NADPH oxidase inhibitor. Our data suggest that insulin-induced phosphorylation of IRβ and Akt is mediated via ROS which are predominantly produced by NADPH oxidase in mouse hypothalamus.
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Jin T, Yu H, Huang XF. Selective binding modes and allosteric inhibitory effects of lupane triterpenes on protein tyrosine phosphatase 1B. Sci Rep 2016; 6:20766. [PMID: 26865097 PMCID: PMC4749975 DOI: 10.1038/srep20766] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 01/04/2016] [Indexed: 12/31/2022] Open
Abstract
Protein Tyrosine Phosphatase 1B (PTP1B) has been recognized as a promising therapeutic target for treating obesity, diabetes, and certain cancers for over a decade. Previous drug design has focused on inhibitors targeting the active site of PTP1B. However, this has not been successful because the active site is positively charged and conserved among the protein tyrosine phosphatases. Therefore, it is important to develop PTP1B inhibitors with alternative inhibitory strategies. Using computational studies including molecular docking, molecular dynamics simulations, and binding free energy calculations, we found that lupane triterpenes selectively inhibited PTP1B by targeting its more hydrophobic and less conserved allosteric site. These findings were verified using two enzymatic assays. Furthermore, the cell culture studies showed that lupeol and betulinic acid inhibited the PTP1B activity stimulated by TNFα in neurons. Our study indicates that lupane triterpenes are selective PTP1B allosteric inhibitors with significant potential for treating those diseases with elevated PTP1B activity.
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Affiliation(s)
- Tiantian Jin
- Centre for Translational Neuroscience, School of Medicine, University of Wollongong, and Illawarra Health and Medical Research Institute (IHMRI), Wollongong, NSW 2522, Australia
| | - Haibo Yu
- School of Chemistry, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Xu-Feng Huang
- Centre for Translational Neuroscience, School of Medicine, University of Wollongong, and Illawarra Health and Medical Research Institute (IHMRI), Wollongong, NSW 2522, Australia
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Borges BDC, Rorato RC, Uchoa ET, Marangon PB, Elias CF, Antunes-Rodrigues J, Elias LLK. Protein tyrosine phosphatase-1B contributes to LPS-induced leptin resistance in male rats. Am J Physiol Endocrinol Metab 2015; 308:E40-50. [PMID: 25352433 PMCID: PMC4280212 DOI: 10.1152/ajpendo.00094.2014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 10/24/2014] [Indexed: 12/18/2022]
Abstract
Leptin resistance is induced by the feedback inhibitors tyrosine phosphatase-1B (PTP1B) and decreased Src homology 2 domain-containing tyrosine phosphatase-2 (SHP-2) signaling. To investigate the participation of PTP1B and SHP-2 in LPS-induced leptin resistance, we injected repeated (6-LPS) intraperitoneal LPS doses (100 μg/kg ip) for comparison with a single (1-LPS) treatment and evaluated the expression of SHP-2, PTP1B, p-ERK1/2, and p-STAT3 in the hypothalamus of male Wistar rats. The single LPS treatment increased the expression of p-STAT3 and PTP1B but not SHP-2. The repeated LPS treatment reduced SHP-2, increased PTP1B, and did not change p-STAT3. We observed that the PTP1B expression induced by the endotoxin was highly colocalized with leptin receptor cells in the hypothalamus of LepRb-IRES-Cre-tdTomato reporter mice. The single, but not the repeated, LPS treatment decreased the food intake and body weight. Leptin had no stimulatory effect on the hypophagia, body weight loss, or pSTAT3 expression in 6-LPS rats, indicating leptin unresponsiveness. Notably, the PTP1B inhibitor (3.0 nmol/rat in 5 μl icv) restored the LPS-induced hypophagia in 6-LPS rats and restored the ability of leptin to reduce food intake and body weight as well as to phosphorylate STAT3 in the arcuate, paraventricular, and ventromedial nuclei of the hypothalamus. The present data suggest that an increased PTP1B expression in the hypothalamus underlies the development of leptin resistance during repeated exposure to LPS. Our findings contribute to understanding the mechanisms involved in leptin resistance during low-grade inflammation as seen in obesity.
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Affiliation(s)
| | - Rodrigo C Rorato
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Brazil; and
| | - Ernane Torres Uchoa
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Brazil; and
| | - Paula B Marangon
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Brazil; and
| | - Carol F Elias
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Jose Antunes-Rodrigues
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Brazil; and
| | - Lucila L K Elias
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Brazil; and
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Adachi K, Goto M, Onoue T, Tsunekawa T, Shibata M, Hagimoto S, Ito Y, Banno R, Suga H, Sugimura Y, Oiso Y, Arima H. Mitogen-activated protein kinase phosphatase 1 negatively regulates MAPK signaling in mouse hypothalamus. Neurosci Lett 2014; 569:49-54. [PMID: 24686178 DOI: 10.1016/j.neulet.2014.03.032] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 03/18/2014] [Accepted: 03/20/2014] [Indexed: 01/09/2023]
Abstract
Mitogen-activated protein kinase phosphatase 1 (MKP-1) is shown to negatively regulate MAPK signaling in various peripheral tissues as well as the central nervous system such as cortex, striatum and hippocampus. In this study, we examined whether MKP-1 regulates MAPK signaling in the mouse hypothalamus. Intraperitoneal injection of TNFα significantly increased MKP-1 mRNA expression in paraventricular and arcuate nuclei in the hypothalamus. TNFα treatment induced increases in MKP-1 expression at both mRNA and protein levels, accompanied by the inactivation of MAPK signaling in mouse hypothalamic explants. Inhibition of MKP-1 by its inhibitor or siRNA increased MAPK activity in the explants. Our data indicate that MKP-1 negatively regulates MAPK signaling in the mouse hypothalamus.
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Affiliation(s)
- Koichi Adachi
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya 466-8550, Japan
| | - Motomitsu Goto
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya 466-8550, Japan.
| | - Takeshi Onoue
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya 466-8550, Japan
| | - Taku Tsunekawa
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya 466-8550, Japan
| | - Miyuki Shibata
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya 466-8550, Japan
| | - Shigeru Hagimoto
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya 466-8550, Japan
| | - Yoshihiro Ito
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya 466-8550, Japan
| | - Ryoichi Banno
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya 466-8550, Japan
| | - Hidetaka Suga
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya 466-8550, Japan
| | - Yoshihisa Sugimura
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya 466-8550, Japan
| | - Yutaka Oiso
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya 466-8550, Japan
| | - Hiroshi Arima
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya 466-8550, Japan.
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Crosstalk Between Insulin and Toll-like Receptor Signaling Pathways in the Central Nervous system. Mol Neurobiol 2014; 50:797-810. [DOI: 10.1007/s12035-013-8631-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 12/25/2013] [Indexed: 01/04/2023]
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GABA type B receptor signaling in proopiomelanocortin neurons protects against obesity, insulin resistance, and hypothalamic inflammation in male mice on a high-fat diet. J Neurosci 2013; 33:17166-73. [PMID: 24155320 DOI: 10.1523/jneurosci.0897-13.2013] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
There is evidence suggesting that the GABA system in the arcuate nucleus, where orexigenic neuropeptide Y and agouti-related peptide as well as anorexigenic proopiomelanocortin (POMC) are expressed, plays an important role in energy balance. In this study, we generated POMC-specific GABAB receptor-deficient [knock-out (KO)] mice. Male KO mice on a high-fat diet (HFD) showed mild increases in body weight (BW) at the age of 9 weeks compared to wild-type (WT) mice, and the differences remained significant until 16 weeks old. However, there was no difference in BW in females between genotypes. While food intake was similar between genotypes, oxygen consumption was significantly decreased in the male KO mice. The insulin tolerance test revealed that the male KO mice were less insulin sensitive compared to WT mice at the age of 8 weeks, when there was no significant difference in BW between genotypes. Despite increased BW, POMC mRNA expression in the arcuate nucleus was significantly decreased in the KO mice compared to WT mice at the age of 16 weeks. Furthermore, the expression of TNFα as well as IL-6, proinflammatory markers in the hypothalamus, was significantly increased in the KO mice on a HFD compared to WT mice. This demonstrates that the deletion of GABAB receptors in POMC neurons in the male mice on a HFD results in obesity, insulin resistance, and hypothalamic inflammation. Furthermore, the decreased POMC expression in the obese KO mice suggests that the regulation of POMC expression through GABAB receptors is essential for proper energy balance.
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Hagimoto S, Arima H, Adachi K, Ito Y, Suga H, Sugimura Y, Goto M, Banno R, Oiso Y. Expression of neuropeptide Y and agouti-related protein mRNA stimulated by glucocorticoids is attenuated via NF-κB p65 under ER stress in mouse hypothalamic cultures. Neurosci Lett 2013; 553:165-9. [DOI: 10.1016/j.neulet.2013.08.040] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2013] [Revised: 08/07/2013] [Accepted: 08/20/2013] [Indexed: 11/27/2022]
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Ponnusamy M, Ma L, Zhuang S. Necrotic renal epithelial cell inhibits renal interstitial fibroblast activation: role of protein tyrosine phosphatase 1B. Am J Physiol Renal Physiol 2013; 304:F698-709. [PMID: 23283996 DOI: 10.1152/ajprenal.00564.2012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Our recent studies showed that contents of necrotic renal proximal tubular cells (RPTC) from 2 × 10(6) cells/ml directly induced death of cultured renal interstitial fibroblasts. However, it remains unknown whether nonlethal number of necrotic RPTC would also alter the fate of renal interstitial fibroblasts. To address this issue, renal interstitial fibroblasts (NRK-49F) were exposed to necrotic RPTC supernatant (RPTC-Sup) obtained from 2 × 10(4) to 5 × 10(5) cells/ml. These concentrations of RPTC did not induce cell death, but led to inactivation of renal fibroblasts as indicated by reduced expression of α-smooth muscle actin and fibronectin, two hallmarks of activated fibroblasts. Concurrently, the same doses of necrotic RPTC-Sup suppressed phosphorylation of epidermal growth factor receptor (EGFR) and signal transducers and activators of transcription-3 (STAT3) in a time- and dose-dependent manner, but did not affect phosphorylation of platelet-derived growth factor receptor-β, AKT, and extracellular signal-regulated kinase 1/2. The presence of sodium orthovanadate, a general protein tyrosine phosphatase (PTP) inhibitor or TCS-401 (a selective PTP1B inhibitor), abrogated those effects of RPTC-Sup, whereas coincubation with the EGFR inhibitor (Gefitinib) or silencing of EGFR with siRNA preserved the ability of RPTC-Sup in suppressing renal fibroblast activation and STAT3 phosphorylation. Moreover, RPTC-Sup treatment induced PTP1B phosphorylation and its interaction with EGFR. Collectively, these results indicate that nonlethal necrotic RPTC-Sup can induce inactivation of renal interstitial fibroblasts, which occurs through a mechanism involved in PTP1B-mediated inhibition of EGFR signaling.
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Affiliation(s)
- Murugavel Ponnusamy
- Department of Medicine, Rhode Island Hospital and Alpert Medical School of Brown University, Providence, RI 02903, USA
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Abstract
A growing number of studies have shown that a diet high in long chain SFA and/or obesity cause profound changes to the energy balance centres of the hypothalamus which results in the loss of central leptin and insulin sensitivity. Insensitivity to these important anorexigenic messengers of nutritional status perpetuates the development of both obesity and peripheral insulin insensitivity. A high-fat diet induces changes in the hypothalamus that include an increase in markers of oxidative stress, inflammation, endoplasmic reticulum (ER) stress, autophagy defect and changes in the rate of apoptosis and neuronal regeneration. In addition, a number of mechanisms have recently come to light that are important in the hypothalamic control of energy balance, which could play a role in perpetuating the effect of a high-fat diet on hypothalamic dysfunction. These include: reactive oxygen species as an important second messenger, lipid metabolism, autophagy and neuronal and synaptic plasticity. The importance of nutritional activation of the Toll-like receptor 4 and the inhibitor of NF-κB kinase subunit β/NK-κB and c-Jun amino-terminal kinase 1 inflammatory pathways in linking a high-fat diet to obesity and insulin insensitivity via the hypothalamus is now widely recognised. All of the hypothalamic changes induced by a high-fat diet appear to be causally linked and inhibitors of inflammation, ER stress and autophagy defect can prevent or reverse the development of obesity pointing to potential drug targets in the prevention of obesity and metabolic dysfunction.
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Tsou RC, Bence KK. The Genetics of PTPN1 and Obesity: Insights from Mouse Models of Tissue-Specific PTP1B Deficiency. J Obes 2012; 2012:926857. [PMID: 22811891 PMCID: PMC3395189 DOI: 10.1155/2012/926857] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Revised: 04/18/2012] [Accepted: 04/18/2012] [Indexed: 02/05/2023] Open
Abstract
The protein tyrosine phosphatase PTP1B is a negative regulator of both insulin and leptin signaling and is involved in the control of glucose homeostasis and energy expenditure. Due to its prominent role in regulating metabolism, PTP1B is a promising therapeutic target for the treatment of human obesity and type 2 diabetes. The PTP1B protein is encoded by the PTPN1 gene on human chromosome 20q13, a region that shows linkage with insulin resistance, type 2 diabetes, and obesity in human populations. In this paper, we summarize the genetics of the PTPN1 locus and associations with metabolic disease. In addition, we discuss the tissue-specific functions of PTP1B as gleaned from genetic mouse models.
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Affiliation(s)
- Ryan C. Tsou
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, Vet 223E, Philadelphia, PA 19104, USA
| | - Kendra K. Bence
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, Vet 223E, Philadelphia, PA 19104, USA
- *Kendra K. Bence:
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