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Jensen-Cody S, Coyne ES, Ding X, Sebin A, Vogel J, Goldstein J, Rosahl TW, Zhou HH, Jacobs H, Champy MF, About GB, Talukdar S, Zhou Y. Loss of low-molecular-weight protein tyrosine phosphatase shows limited improvement in glucose tolerance but causes mild cardiac hypertrophy in mice. Am J Physiol Endocrinol Metab 2022; 322:E517-E527. [PMID: 35403438 DOI: 10.1152/ajpendo.00161.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Insulin resistance is a major public health burden that often results in other comorbidities including type 2 diabetes, nonalcoholic fatty liver disease (NAFLD), and cardiovascular disease. An insulin sensitizer has the potential to become a disease-modifying therapy. It remains an unmet medical need to identify therapeutics that target the insulin signaling pathway to treat insulin resistance. Low-molecular-weight protein tyrosine phosphatase (LMPTP) negatively regulates insulin signaling and has emerged as a potential therapeutic target for insulin sensitization. Genetic studies have demonstrated that LMPTP is positively associated with obesity in humans and promotes insulin resistance in rodents. A recent study showed that pharmacological inhibition or genetic deletion of LMPTP protects mice from high-fat diet-induced insulin resistance and diabetes. Here, we show that loss of LMPTP by genetic deletion has no significant effects on improving glucose tolerance in lean or diet-induced obese mice. Furthermore, our data demonstrate that LMPTP deficiency potentiates cardiac hypertrophy that leads to mild cardiac dysfunction. Our findings suggest that the development of LMPTP inhibitors for the treatment of insulin resistance and type 2 diabetes should be reevaluated, and further studies are needed to characterize the molecular and pathophysiological role of LMPTP.NEW & NOTEWORTHY Inhibition of LMPTP with a small-molecule inhibitor, Cmpd23, improves glucose tolerance in mice as reported earlier. However, genetic deficiency of the LMPTP-encoding gene, Acp1, has limited effects on glucose metabolism but leads to mild cardiac hypertrophy in mice. The findings suggest the potential off-target effects of Cmpd23 and call for reevaluation of LMPTP as a therapeutic target for the treatment of insulin resistance and type 2 diabetes.
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Affiliation(s)
| | - Erin S Coyne
- Merck & Co., Inc., South San Francisco, California
| | - Xunshan Ding
- Merck & Co., Inc., South San Francisco, California
| | - Anu Sebin
- Merck & Co., Inc., South San Francisco, California
| | - Jen Vogel
- Merck & Co., Inc., South San Francisco, California
| | | | | | | | - Hugues Jacobs
- CELPHEDIA, PHENOMIN, Institut Clinique de la Souris, Université de Strasbourg, CNRS, INSERM, Illkirch, France
| | - Marie-France Champy
- CELPHEDIA, PHENOMIN, Institut Clinique de la Souris, Université de Strasbourg, CNRS, INSERM, Illkirch, France
| | - Ghina Bou About
- CELPHEDIA, PHENOMIN, Institut Clinique de la Souris, Université de Strasbourg, CNRS, INSERM, Illkirch, France
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Kornicka-Garbowska K, Bourebaba L, Röcken M, Marycz K. Inhibition of protein tyrosine phosphatase improves mitochondrial bioenergetics and dynamics, reduces oxidative stress, and enhances adipogenic differentiation potential in metabolically impaired progenitor stem cells. Cell Commun Signal 2021; 19:106. [PMID: 34732209 PMCID: PMC8565043 DOI: 10.1186/s12964-021-00772-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 07/30/2021] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Protein tyrosine phosphatase 1B (PTP1B) and low molecular weight protein tyrosine phosphatase (LMPTP) are implicated in the development of metabolic disorders. Yet, their role in progenitor stem cell adipogenic differentiation and modulation of mitochondrial dynamics remains elusive. METHODS In this study, we decided to investigate whether inhibition of PTP1B and LMPTP enhance adipogenic differentiation of metabolically impaired progenitor stem cells via modulation of mitochondrial bioenergetics and dynamics. Cells were cultured under adipogenic conditions in the presence of PTP1B and LMPTP inhibitors, and were subjected to the analysis of the main adipogenic-related and mitochondrial-related genes using RT-qPCR. Protein levels were established with western blot while mitochondrial morphology with MicroP software. RESULTS Selective inhibitors of both PTP1B and MPTP enhanced adipogenic differentiation of metabolically impaired progenitor stem cells. We have observed enhanced expression of PPARy and adiponectin in treated cells. What is more, increased antioxidative defence and alternations in mitochondrial bioenergetics were observed. We have found that inhibition of PTP1B as well as C23 activates oxidative phosphorylation and enhances mitochondrial fusion contributing to enhanced adipogenesis. CONCLUSIONS The presented data provides evidence that the application of PTP1B and LMPTP inhibitors enhances adipogenesis through the modulation of mitochondrial dynamics. Video abstract.
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Affiliation(s)
- Katarzyna Kornicka-Garbowska
- Department of Experimental Biology, Wroclaw University of Environmental and Life Sciences, Norwida 27B Street, A7 building, 50-375 Wroclaw, Poland
- International Institute of Translational Medicine, Malin, Jesionowa 11, 55-114 Wisznia Mała, Poland
| | - Lynda Bourebaba
- Department of Experimental Biology, Wroclaw University of Environmental and Life Sciences, Norwida 27B Street, A7 building, 50-375 Wroclaw, Poland
| | - Michael Röcken
- Faculty of Veterinary Medicine, Equine Clinic-Equine Surgery, Justus-Liebig University, 35392 Giessen, Germany
| | - Krzysztof Marycz
- Department of Experimental Biology, Wroclaw University of Environmental and Life Sciences, Norwida 27B Street, A7 building, 50-375 Wroclaw, Poland
- International Institute of Translational Medicine, Malin, Jesionowa 11, 55-114 Wisznia Mała, Poland
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Stanford SM, Collins M, Diaz MA, Holmes ZJ, Gries P, Bliss MR, Lodi A, Zhang V, Tiziani S, Bottini N. The low molecular weight protein tyrosine phosphatase promotes adipogenesis and subcutaneous adipocyte hypertrophy. J Cell Physiol 2021; 236:6630-6642. [PMID: 33615467 DOI: 10.1002/jcp.30307] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 12/29/2020] [Accepted: 01/15/2021] [Indexed: 12/28/2022]
Abstract
Obesity is a major contributing factor to the pathogenesis of Type 2 diabetes. Multiple human genetics studies suggest that high activity of the low molecular weight protein tyrosine phosphatase (LMPTP) promotes metabolic syndrome in obesity. We reported that LMPTP is a critical promoter of insulin resistance in obesity by regulating liver insulin receptor signaling and that inhibition of LMPTP reverses obesity-associated diabetes in mice. Since LMPTP is expressed in adipose tissue but little is known about its function, here we examined the role of LMPTP in adipocyte biology. Using conditional knockout mice, we found that selective deletion of LMPTP in adipocytes impaired obesity-induced subcutaneous adipocyte hypertrophy. We assessed the role of LMPTP in adipogenesis in vitro, and found that LMPTP deletion or knockdown substantially impaired differentiation of primary preadipocytes and 3T3-L1 cells into adipocytes, respectively. Inhibition of LMPTP in 3T3-L1 preadipocytes also reduced adipogenesis and expression of proadipogenic transcription factors peroxisome proliferator activated receptor gamma (PPARγ) and CCAAT/enhancer-binding protein alpha. Inhibition of LMPTP increased basal phosphorylation of platelet-derived growth factor receptor alpha (PDGFRα) on activation motif residue Y849 in 3T3-L1, resulting in increased activation of the mitogen-associated protein kinases p38 and c-Jun N-terminal kinase and increased PPARγ phosphorylation on inhibitory residue S82. Analysis of the metabolome of differentiating 3T3-L1 cells suggested that LMPTP inhibition decreased cell glucose utilization while enhancing mitochondrial respiration and nucleotide synthesis. In summary, we report a novel role for LMPTP as a key driver of adipocyte differentiation via control of PDGFRα signaling.
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Affiliation(s)
- Stephanie M Stanford
- Department of Medicine, University of California, San Diego, La Jolla, California, USA.,Division of Cellular Biology, La Jolla Institute for Allergy and Immunology, La Jolla, California, USA
| | - Meghan Collins
- Department of Nutritional Sciences, The University of Texas at Austin, Austin, Texas, USA.,Department of Pediatrics, Dell Medical School, The University of Texas at Austin, Austin, Texas, USA
| | - Michael A Diaz
- Department of Medicine, University of California, San Diego, La Jolla, California, USA
| | - Zachary J Holmes
- Department of Medicine, University of California, San Diego, La Jolla, California, USA
| | - Paul Gries
- Department of Nutritional Sciences, The University of Texas at Austin, Austin, Texas, USA.,Department of Pediatrics, Dell Medical School, The University of Texas at Austin, Austin, Texas, USA
| | - Matthew R Bliss
- Division of Cellular Biology, La Jolla Institute for Allergy and Immunology, La Jolla, California, USA
| | - Alessia Lodi
- Department of Nutritional Sciences, The University of Texas at Austin, Austin, Texas, USA.,Department of Pediatrics, Dell Medical School, The University of Texas at Austin, Austin, Texas, USA
| | - Vida Zhang
- Department of Medicine, University of California, San Diego, La Jolla, California, USA.,Division of Cellular Biology, La Jolla Institute for Allergy and Immunology, La Jolla, California, USA
| | - Stefano Tiziani
- Department of Nutritional Sciences, The University of Texas at Austin, Austin, Texas, USA.,Department of Pediatrics, Dell Medical School, The University of Texas at Austin, Austin, Texas, USA.,Department of Oncology, Dell Medical School, The University of Texas at Austin, Austin, Texas, USA
| | - Nunzio Bottini
- Department of Medicine, University of California, San Diego, La Jolla, California, USA.,Division of Cellular Biology, La Jolla Institute for Allergy and Immunology, La Jolla, California, USA
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Bourebaba L, Łyczko J, Alicka M, Bourebaba N, Szumny A, Fal AM, Marycz K. Inhibition of Protein-tyrosine Phosphatase PTP1B and LMPTP Promotes Palmitate/Oleate-challenged HepG2 Cell Survival by Reducing Lipoapoptosis, Improving Mitochondrial Dynamics and Mitigating Oxidative and Endoplasmic Reticulum Stress. J Clin Med 2020; 9:E1294. [PMID: 32369900 DOI: 10.3390/jcm9051294] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 04/25/2020] [Accepted: 04/27/2020] [Indexed: 12/12/2022] Open
Abstract
Objectives: Non-alcoholic fatty liver disease (NAFLD) is considered a well-known pathology that is determined without using alcohol and has emerged as a growing public health problem. Lipotoxicity is known to promote hepatocyte death, which, in the context of NAFLD, is termed lipoapoptosis. The severity of NAFLD correlates with the degree of hepatocyte lipoapoptosis. Protein–tyrosine phosphatases (PTP) including PTP1B and Low molecular weight PTP (LMPTP), are negative regulators of the insulin signaling pathway and are considered a promising therapeutic target in the treatment of diabetes. In this study, we hypothesized that the inhibition of PTP1B and LMPTP may potentially prevent hepatocyte apoptosis, mitochondrial dysfunction and endoplasmic reticulum (ER) stress onset, following lipotoxicity induced using a free fatty acid (FFA) mixture. Methods: HepG2 cells were cultured in the presence or absence of two PTP inhibitors, namely MSI-1436 and Compound 23, prior to palmitate/oleate overloading. Apoptosis, ER stress, oxidative stress, and mitochondrial dynamics were then evaluated by either MUSE or RT-qPCR analysis. Results: The obtained data demonstrate that the inhibition of PTP1B and LMPTP prevents apoptosis induced by palmitate and oleate in the HepG2 cell line. Moreover, mitochondrial dynamics were positively improved following inhibition of the enzyme, with concomitant oxidative stress reduction and ER stress abrogation. Conclusion: In conclusion, PTP’s inhibitory properties may be a promising therapeutic strategy for the treatment of FFA-induced lipotoxicity in the liver and ultimately in the management of the NAFLD condition.
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Alicka M, Kornicka-Garbowska K, Roecken M, Marycz K. Inhibition of the Low Molecular Weight Protein Tyrosine Phosphatase ( LMPTP) as a Potential Therapeutic Strategy for Hepatic Progenitor Cells Lipotoxicity-Short Communication. Int J Mol Sci 2019; 20:E5873. [PMID: 31771123 DOI: 10.3390/ijms20235873] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 11/20/2019] [Accepted: 11/21/2019] [Indexed: 12/21/2022] Open
Abstract
Equine metabolic syndrome (EMS) is a cluster of metabolic disorders, such as obesity, hyperinsulinemia, and hyperleptinemia, as well as insulin resistance (IR). In accordance with the theory linking obesity and IR, excessive accumulation of lipids in insulin-sensitive tissues (lipotoxicity), like liver, alters several cellular functions, including insulin signaling. Therefore, the purpose of the study was to isolate equine hepatic progenitor-like cells (HPCs) and assess whether inhibition of low molecular weight protein tyrosine phosphatase (LMPTP) affects the expression of genes involved in macroautophagy, chaperone-mediated autophagy (CMA), endoplasmic reticulum stress, and mitochondrial dynamics in a palmitate-induced IR model. We demonstrated that LMPTP inhibition significantly enhanced expression of heat shock cognate 70 kDa protein (HSC70), lysosome-associated membrane protein 2 (LAMP2), and parkin (PRKN), all master regulators of selective autophagy. We also observed downregulation of C/EBP homologous protein (CHOP), activating transcription factor 6 (ATF6) and binding immunoglobulin protein encoded by the HSPA gene. Moreover, LMPTP inhibition increased alternative splicing of X-box binding protein 1 (XBP1), suggesting high endonuclease activity of inositol-requiring enzyme 1 alpha (IRE1α). Taken together, our data provide convincing evidence that LMPTP inhibition reverses palmitate-induced insulin resistance and lipotoxicity. In conclusion, this study highlights the role of LMPTP in the regulation of CMA, mitophagy, and ER stress, and provides a new in vitro model for studying HPC lipotoxicity in pre-clinical research.
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