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Timme K, González-Alvarez ME, Keating AF. Pre-pubertal obesity compromises ovarian oxidative stress, DNA repair and chemical biotransformation. Toxicol Appl Pharmacol 2024; 489:116981. [PMID: 38838792 DOI: 10.1016/j.taap.2024.116981] [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: 03/11/2024] [Revised: 05/22/2024] [Accepted: 05/25/2024] [Indexed: 06/07/2024]
Abstract
Obesity in adult females impairs fertility by altering oxidative stress, DNA repair and chemical biotransformation. Whether prepubertal obesity results in similar ovarian impacts is under-explored. The objective of this study was to induce obesity in prepubertal female mice and assess puberty onset, follicle number, and abundance of oxidative stress, DNA repair and chemical biotransformation proteins basally and in response to 7,12-dimethylbenz(a)anthracene (DMBA) exposure. DMBA is a polycyclic aromatic hydrocarbon that has been shown to be ovotoxic. Lactating dams (C57BL6J) were fed either a normal rodent containing 3.5% kCal from fat (lean), or a high fat diet comprised of 60% kCal from fat, and 9% kCal from sucrose. The offspring were weaned onto the diet of their dam and exposed at postnatal day 35 to either corn oil or DMBA (1 mg/kg) for 7 d via intraperitoneal injection. Mice on the HFD had reduced (P < 0.05) age at puberty onset as measured by vaginal opening but DMBA did not impact puberty onset. Heart, spleen, kidney, uterus and ovary weight were increased (P < 0.05) by obesity and liver weight was increased (P < 0.05) by DMBA exposure in obese mice. Follicle number was largely unaffected by obesity or DMBA exposure, with the exception of primary follicle number, which were higher (P < 0.05) in lean DMBA exposed and obese control relative to lean control mice. There were also greater numbers (P < 0.05) of corpora lutea in obese relative to lean mice. In lean mice, DMBA exposure reduced (P < 0.05) the level of CYP2E1, EPHX1, GSTP1, BRCA1, and CAT but this DMBA-induced reduction was absent in obese mice. Basally, obesity reduced (P < 0.05) the abundance of CYP2E1, EPHX1, GSTP1, BRCA1, SOD1 and CAT. There was greater (P < 0.05) fibrotic staining in obese DMBA-exposed ovaries and PPP2CA was decreased (P < 0.05) in growing follicles by both obesity and DMBA exposure. Thus, prepubertal obesity alters the capacity of the ovary to respond to DNA damage, ovotoxicant exposure and oxidative stress.
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Affiliation(s)
- Kelsey Timme
- Department of Animal Science, Iowa State University, Ames, IA, USA
| | | | - Aileen F Keating
- Department of Animal Science, Iowa State University, Ames, IA, USA.
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2
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Maestas MM, Ishahak M, Augsornworawat P, Veronese-Paniagua DA, Maxwell KG, Velazco-Cruz L, Marquez E, Sun J, Shunkarova M, Gale SE, Urano F, Millman JR. Identification of unique cell type responses in pancreatic islets to stress. Nat Commun 2024; 15:5567. [PMID: 38956087 PMCID: PMC11220140 DOI: 10.1038/s41467-024-49724-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 06/14/2024] [Indexed: 07/04/2024] Open
Abstract
Diabetes involves the death or dysfunction of pancreatic β-cells. Analysis of bulk sequencing from human samples and studies using in vitro and in vivo models suggest that endoplasmic reticulum and inflammatory signaling play an important role in diabetes progression. To better characterize cell type-specific stress response, we perform multiplexed single-cell RNA sequencing to define the transcriptional signature of primary human islet cells exposed to endoplasmic reticulum and inflammatory stress. Through comprehensive pair-wise analysis of stress responses across pancreatic endocrine and exocrine cell types, we define changes in gene expression for each cell type under different diabetes-associated stressors. We find that β-, α-, and ductal cells have the greatest transcriptional response. We utilize stem cell-derived islets to study islet health through the candidate gene CIB1, which was upregulated under stress in primary human islets. Our findings provide insights into cell type-specific responses to diabetes-associated stress and establish a resource to identify targets for diabetes therapeutics.
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Affiliation(s)
- Marlie M Maestas
- Roy and Diana Vagelos Division of Biology and Biomedical Sciences, Washington University School of Medicine, MSC 8127-057-08, 660 South Euclid Avenue, St. Louis, MO, 63110, USA
- Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, MSC 8127-057-08, St. Louis, USA
| | - Matthew Ishahak
- Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, MSC 8127-057-08, St. Louis, USA
| | - Punn Augsornworawat
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, 10700, Thailand
| | - Daniel A Veronese-Paniagua
- Roy and Diana Vagelos Division of Biology and Biomedical Sciences, Washington University School of Medicine, MSC 8127-057-08, 660 South Euclid Avenue, St. Louis, MO, 63110, USA
- Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, MSC 8127-057-08, St. Louis, USA
| | - Kristina G Maxwell
- Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, MSC 8127-057-08, St. Louis, USA
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, USA
| | - Leonardo Velazco-Cruz
- Roy and Diana Vagelos Division of Biology and Biomedical Sciences, Washington University School of Medicine, MSC 8127-057-08, 660 South Euclid Avenue, St. Louis, MO, 63110, USA
- Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, MSC 8127-057-08, St. Louis, USA
| | - Erica Marquez
- Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, MSC 8127-057-08, St. Louis, USA
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, USA
| | - Jiameng Sun
- Roy and Diana Vagelos Division of Biology and Biomedical Sciences, Washington University School of Medicine, MSC 8127-057-08, 660 South Euclid Avenue, St. Louis, MO, 63110, USA
- Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, MSC 8127-057-08, St. Louis, USA
| | - Mira Shunkarova
- Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, MSC 8127-057-08, St. Louis, USA
| | - Sarah E Gale
- Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, MSC 8127-057-08, St. Louis, USA
| | - Fumihiko Urano
- Roy and Diana Vagelos Division of Biology and Biomedical Sciences, Washington University School of Medicine, MSC 8127-057-08, 660 South Euclid Avenue, St. Louis, MO, 63110, USA
- Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, MSC 8127-057-08, St. Louis, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, USA
| | - Jeffrey R Millman
- Roy and Diana Vagelos Division of Biology and Biomedical Sciences, Washington University School of Medicine, MSC 8127-057-08, 660 South Euclid Avenue, St. Louis, MO, 63110, USA.
- Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, MSC 8127-057-08, St. Louis, USA.
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, USA.
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Choi S, Sarker MK, Yu MR, Lee H, Kwon SH, Jeon JS, Noh H, Kim H. MicroRNA-5010-5p ameliorates high-glucose induced inflammation in renal tubular epithelial cells by modulating the expression of PPP2R2D. BMJ Open Diabetes Res Care 2024; 12:e003784. [PMID: 38442987 PMCID: PMC11146382 DOI: 10.1136/bmjdrc-2023-003784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 02/08/2024] [Indexed: 03/07/2024] Open
Abstract
INTRODUCTION We previously reported the significant upregulation of eight circulating exosomal microRNAs (miRNAs) in patients with diabetic kidney disease (DKD). However, their specific roles and molecular mechanisms in the kidney remain unknown. Among the eight miRNAs, we evaluated the effects of miR-5010-5p on renal tubular epithelial cells under diabetic conditions in this study. RESEARCH DESIGN AND METHODS We transfected the renal tubular epithelial cell line, HK-2, with an miR-5010-5p mimic using recombinant plasmids. The target gene of hsa-miR-5010-5p was identified using a dual-luciferase assay. Cell viability was assessed via the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay. Moreover, mRNA and protein expression levels were determined via real-time PCR and western blotting, respectively. RESULTS High glucose levels did not significantly affect the intracellular expression of miR-5010-5p in HK-2 cells. Transfection of the miR-5010-5p mimic caused no change in cell viability. However, miR-5010-5p-transfected HK-2 cells exhibited significantly decreased expression levels of inflammatory cytokines, such as the monocyte chemoattractant protein-1, interleukin-1β, and tumor necrosis factor-ɑ, under high-glucose conditions. These changes were accompanied by the restored expression of phosphorylated AMP-activated protein kinase (AMPK) and decreased phosphorylation of nuclear factor-kappa B. Dual-luciferase assay revealed that miR-5010-5p targeted the gene, protein phosphatase 2 regulatory subunit B delta (PPP2R2D), a subunit of protein phosphatase 2A, which modulates AMPK phosphorylation. CONCLUSIONS Our findings suggest that increased miR-5010-5p expression reduces high glucose-induced inflammatory responses in renal tubular epithelial cells via the regulation of the target gene, PPP2R2D, which modulates AMPK phosphorylation. Therefore, miR-5010-5p may be a promising therapeutic target for DKD.
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Affiliation(s)
- Sunghee Choi
- Hyonam Kidney Laboratory, Seoul, Korea (the Republic of)
| | | | - Mi Ra Yu
- Hyonam Kidney Laboratory, Seoul, Korea (the Republic of)
| | - Haekyung Lee
- Hyonam Kidney Laboratory, Seoul, Korea (the Republic of)
- Division of Nephrology, Department of Internal Medicine, Soonchunhyang University Seoul Hospital, Seoul, Korea (the Republic of)
| | - Soon Hyo Kwon
- Hyonam Kidney Laboratory, Seoul, Korea (the Republic of)
- Division of Nephrology, Department of Internal Medicine, Soonchunhyang University Seoul Hospital, Seoul, Korea (the Republic of)
| | - Jin Seok Jeon
- Hyonam Kidney Laboratory, Seoul, Korea (the Republic of)
- Division of Nephrology, Department of Internal Medicine, Soonchunhyang University Seoul Hospital, Seoul, Korea (the Republic of)
| | - Hyunjin Noh
- Hyonam Kidney Laboratory, Seoul, Korea (the Republic of)
- Division of Nephrology, Department of Internal Medicine, Soonchunhyang University Seoul Hospital, Seoul, Korea (the Republic of)
| | - Hyoungnae Kim
- Hyonam Kidney Laboratory, Seoul, Korea (the Republic of)
- Division of Nephrology, Department of Internal Medicine, Soonchunhyang University Seoul Hospital, Seoul, Korea (the Republic of)
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Zhang Z, Tong B, Liu J, Feng J, Song L, Wang H, Ke M, Xu C, Xu Y. PP2Ac knockdown attenuates lipotoxicity‑induced pancreatic β‑cell dysfunction and apoptosis. Exp Ther Med 2023; 26:549. [PMID: 37928506 PMCID: PMC10623214 DOI: 10.3892/etm.2023.12247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 09/20/2023] [Indexed: 11/07/2023] Open
Abstract
Protein phosphatase 2A (PP2A) is one of the most common serine/threonine phosphatases in mammalian cells, and it primarily functions to regulate cell signaling, glycolipid metabolism and apoptosis. The catalytic subunit of PP2A (PP2Ac) plays an important role in the functions of the protein. However, there are few reports on the regulatory role of PP2Ac in pancreatic β-cells under lipotoxic conditions. In the present study, mouse insulinoma 6 (MIN6) pancreatic cells were transfected with short hairpin RNAs to generate PP2Ac knockdown cells and incubated with palmitate (PA) to establish a lipotoxicity model. Serine/threonine phosphatase assay system, Cell Counting Kit-8, flow cytometry, enzyme-linked immunosorbent assay and western blotting were used to measure PP2A activity, cell viability, apoptosis, oxidative stress and insulin secretion in the cells. In addition, a mouse model of lipotoxicity was established with a high-fat diet (HFD) and the knockdown of PP2Ac using adeno-associated viruses to interfere with PP2Ac expression in the pancreatic tissues. The activity of PP2A in the mouse pancreatic tissue and the serum insulin level were measured. Furthermore, the proliferation of mouse pancreatic β-cells was assessed using pancreatic tissue immunofluorescence. PP2Ac knockdown inhibited lipotoxicity-induced PP2A hyperactivation, increased the resistance of pancreatic β-cells to lipotoxicity and attenuated PA-induced apoptosis in MIN6 cells. It also protected the endoplasmic reticulum and mitochondria, and ameliorated insulin secretion. The results of mRNA sequencing and western blotting analysis suggested that the protective effects of PP2Ac knockdown in MIN6 cells may be mediated via the MAPK pathway. Moreover, the results of the animal experiments suggested that specific knockdown of pancreatic PP2Ac effectively attenuated HFD-induced insulin resistance and reduced the compensatory proliferation of pancreatic β-cells in mice. In summary, the present study revealed the effects of interfering with PP2Ac gene expression on pancreatic β-cells in vivo and in vitro and the underlying mechanisms, which may provide insights for the treatment of type 2 diabetes mellitus in the clinic.
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Affiliation(s)
- Zhengwei Zhang
- Department of Endocrinology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei 430071, P.R. China
| | - Beier Tong
- Department of Endocrinology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei 430071, P.R. China
| | - Jie Liu
- Department of Endocrinology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei 430071, P.R. China
| | - Jieyuan Feng
- Department of Endocrinology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei 430071, P.R. China
| | - Linyang Song
- Department of Endocrinology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei 430071, P.R. China
| | - Huawei Wang
- Department of Endocrinology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei 430071, P.R. China
| | - Mengting Ke
- Department of Endocrinology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei 430071, P.R. China
| | - Chengkai Xu
- Department of Endocrinology, Suizhou Central Hospital, Suizhou, Hubei 441300, P.R. China
| | - Yancheng Xu
- Department of Endocrinology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei 430071, P.R. China
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Le TKC, Dao XD, Nguyen DV, Luu DH, Bui TMH, Le TH, Nguyen HT, Le TN, Hosaka T, Nguyen TTT. Insulin signaling and its application. Front Endocrinol (Lausanne) 2023; 14:1226655. [PMID: 37664840 PMCID: PMC10469844 DOI: 10.3389/fendo.2023.1226655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 07/19/2023] [Indexed: 09/05/2023] Open
Abstract
The discovery of insulin in 1921 introduced a new branch of research into insulin activity and insulin resistance. Many discoveries in this field have been applied to diagnosing and treating diseases related to insulin resistance. In this mini-review, the authors attempt to synthesize the updated discoveries to unravel the related mechanisms and inform the development of novel applications. Firstly, we depict the insulin signaling pathway to explain the physiology of insulin action starting at the receptor sites of insulin and downstream the signaling of the insulin signaling pathway. Based on this, the next part will analyze the mechanisms of insulin resistance with two major provenances: the defects caused by receptors and the defects due to extra-receptor causes, but in this study, we focus on post-receptor causes. Finally, we discuss the recent applications including the diseases related to insulin resistance (obesity, cardiovascular disease, Alzheimer's disease, and cancer) and the potential treatment of those based on insulin resistance mechanisms.
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Affiliation(s)
- Thi Kim Chung Le
- School of Preventive Medicine and Public Health, Hanoi Medical University, Hanoi, Vietnam
| | - Xuan Dat Dao
- School of Preventive Medicine and Public Health, Hanoi Medical University, Hanoi, Vietnam
| | - Dang Vung Nguyen
- School of Preventive Medicine and Public Health, Hanoi Medical University, Hanoi, Vietnam
| | - Duc Huy Luu
- Department of Biopharmaceuticals, Institute of Chemistry, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | - Thi Minh Hanh Bui
- School of Preventive Medicine and Public Health, Hanoi Medical University, Hanoi, Vietnam
| | - Thi Huong Le
- School of Preventive Medicine and Public Health, Hanoi Medical University, Hanoi, Vietnam
| | - Huu Thang Nguyen
- School of Preventive Medicine and Public Health, Hanoi Medical University, Hanoi, Vietnam
| | - Tran Ngoan Le
- School of Preventive Medicine and Public Health, Hanoi Medical University, Hanoi, Vietnam
| | - Toshio Hosaka
- Department of Food and Nutritional Sciences, University of Shizuoka, Shizuoka, Japan
| | - Thi Thu Thao Nguyen
- School of Preventive Medicine and Public Health, Hanoi Medical University, Hanoi, Vietnam
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6
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Salter EA, Wierzbicki A, Honkanen RE, Swingle MR. Quantum-based modeling implies that bidentate Arg 89-substrate binding enhances serine/threonine protein phosphatase-2A(PPP2R5D/PPP2R1A/PPP2CA)-mediated dephosphorylation. Front Cell Dev Biol 2023; 11:1141804. [PMID: 37377738 PMCID: PMC10291244 DOI: 10.3389/fcell.2023.1141804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 06/02/2023] [Indexed: 06/29/2023] Open
Abstract
PP2A-serine/threonine protein phosphatases function as heterotrimeric holoenzymes, composed of a common scaffold (A-subunit encoded by PPP2R1A/PPP2R1B), a common catalytic (C-subunit encoded by PPP2CA/PPP2CB), and one of many variable regulatory (B) subunits. The site of phosphoprotein phosphatase (PPP) hydrolysis features a bimetal system (M1/M2), an associated bridge hydroxide [W1(OH-)], and a highly-conserved core sequence. In the presumptive common mechanism, the phosphoprotein's seryl/threonyl phosphate coordinates the M1/M2 system, W1(OH-) attacks the central P atom, rupturing the antipodal bond, and simultaneously, a histidine/aspartate tandem protonates the exiting seryl/threonyl alkoxide. Based on studies of PPP5C, a conserved arginine proximal to M1 is also expected to bind the substrate's phosphate group in a bidentate fashion. However, in PP2A isozymes, the role of the arginine (Arg89) in hydrolysis is not clear because two independent structures for PP2A(PPP2R5C) and PP2A(PPP2R5D) show that Arg89 engages in a weak salt bridge at the B:C interface. These observations raise the question of whether hydrolysis proceeds with or without direct involvement of Arg89. The interaction of Arg89 with B:Glu198 in PP2A(PPP2R5D) is significant because the pathogenic E198K variant of B56δ is associated with irregular protein phosphorylation levels and consequent developmental disorders (Jordan's Syndrome; OMIM #616355). In this study, we perform quantum-based hybrid [ONIOM(UB3LYP/6-31G(d):UPM7)] calculations on 39-residue models of the PP2A(PPP2R5D)/pSer (phosphoserine) system to estimate activation barriers for hydrolysis in the presence of bidentate Arg89-substrate binding and when Arg89 is otherwise engaged in the salt-bridge interaction. Our solvation-corrected results yield ΔH‡ ≈ ΔE‡ = +15.5 kcal/mol for the former case, versus +18.8 kcal/mol for the latter, indicating that bidentate Arg89-substrate binding is critical for optimal catalytic function of the enzyme. We speculate that PP2A(PPP2R5D) activity is suppressed by B:Glu198 sequestration of C:Arg89 under native conditions, whereas the PP2A(PPP2R5D)-holoenzyme containing the E198K variant has a positively-charged lysine in this position that alters normal function.
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Affiliation(s)
- E. Alan Salter
- Department of Chemistry, University of South Alabama, Mobile, AL, United States
| | - Andrzej Wierzbicki
- Department of Chemistry, University of South Alabama, Mobile, AL, United States
| | - Richard E. Honkanen
- Department of Biochemistry and Molecular Biology, College of Medicine, University of South Alabama, Mobile, AL, United States
| | - Mark R. Swingle
- Department of Biochemistry and Molecular Biology, College of Medicine, University of South Alabama, Mobile, AL, United States
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Alghanem L, Zhang X, Jaiswal R, Seyoum B, Mallisho A, Msallaty Z, Yi Z. Effect of Insulin and Pioglitazone on Protein Phosphatase 2A Interaction Partners in Primary Human Skeletal Muscle Cells Derived from Obese Insulin-Resistant Participants. ACS OMEGA 2022; 7:42763-42773. [PMID: 36467954 PMCID: PMC9713796 DOI: 10.1021/acsomega.2c04473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 11/01/2022] [Indexed: 05/16/2023]
Abstract
Skeletal muscle insulin resistance is a major contributor to type-2 diabetes (T2D). Pioglitazone is a potent insulin sensitizer of peripheral tissues by targeting peroxisome proliferator-activated receptor gamma. Pioglitazone has been reported to protect skeletal muscle cells from lipotoxicity by promoting fatty acid mobilization and insulin signaling. However, it is unclear whether pioglitazone increases insulin sensitivity through changes in protein-protein interactions involving protein phosphatase 2A (PP2A). PP2A regulates various cell signaling pathways such as insulin signaling. Interaction of the catalytic subunit of PP2A (PP2Ac) with protein partners is required for PP2A specificity and activity. Little is known about PP2Ac partners in primary human skeletal muscle cells derived from lean insulin-sensitive (Lean) and obese insulin-resistant (OIR) participants. We utilized a proteomics method to identify PP2Ac interaction partners in skeletal muscle cells derived from Lean and OIR participants, with or without insulin and pioglitazone treatments. In this study, 216 PP2Ac interaction partners were identified. Furthermore, 26 PP2Ac partners exhibited significant differences in their interaction with PP2Ac upon insulin treatments between the two groups. Multiple pathways and molecular functions are significantly enriched for these 26 interaction partners, such as nonsense-mediated decay, metabolism of RNA, RNA binding, and protein binding. Interestingly, pioglitazone restored some of these abnormalities. These results provide differential PP2Ac complexes in Lean and OIR in response to insulin/pioglitazone, which may help understand molecular mechanisms underpinning insulin resistance and the insulin-sensitizing effects of pioglitazone treatments, providing multiple targets in various pathways to reverse insulin resistance and prevent and/or manage T2D with less drug side effects.
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Affiliation(s)
- Lana Alghanem
- Department
of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan48201, United States
| | - Xiangmin Zhang
- Department
of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan48201, United States
| | - Ruchi Jaiswal
- Department
of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan48201, United States
| | - Berhane Seyoum
- Division
of Endocrinology, Wayne State University School of Medicine, Wayne State University, Detroit, Michigan48201, United States
| | - Abdullah Mallisho
- Division
of Endocrinology, Wayne State University School of Medicine, Wayne State University, Detroit, Michigan48201, United States
| | - Zaher Msallaty
- Division
of Endocrinology, Wayne State University School of Medicine, Wayne State University, Detroit, Michigan48201, United States
| | - Zhengping Yi
- Department
of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan48201, United States
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8
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Hali M, Wadzinski BE, Kowluru A. Alpha4 contributes to the dysfunction of the pancreatic beta cell under metabolic stress. Mol Cell Endocrinol 2022; 557:111754. [PMID: 35987388 PMCID: PMC9620510 DOI: 10.1016/j.mce.2022.111754] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 08/10/2022] [Accepted: 08/12/2022] [Indexed: 11/30/2022]
Abstract
The current study examined the roles of Alpha4, a non-canonical subunit of protein phosphatase 2A, in the regulation of acute (insulin secretion) and chronic (cell dysfunction) effects of glucose in pancreatic beta cells. Alpha4 is expressed in human islets, rat islets and INS-1832/13 cells. Incubation of INS-1832/13 cells and rat islets with high glucose (HG) significantly increased the expression of Alpha4. C2-Ceramide, a biologically active sphingolipid, also increased the expression of Alpha4 in INS-1832/13 cells and rat islets. Subcellular distribution studies of Alpha4 in low glucose (LG) and HG exposed INS-1832/13 cells revealed that it is predominantly cytosolic, and its expression is significantly increased in the non-nuclear/cytosolic fractions in cells exposed to HG. siRNA-mediated knockdown of Alpha4 exerted minimal effects on glucose- or KCl-induced insulin secretion. siRNA-mediated deletion of Alpha4 significantly increased p38MAPK and JNK1/2 phosphorylation under LG conditions, comparable to the degree seen under HG conditions. Paradoxically, a significant potentiation of HG-induced p38MAPK and JNK2 phosphorylation was noted following Alpha4 deletion. HG-induced CHOP expression (ER stress marker) and caspase-3 activation were markedly attenuated in cells following Alpha4 knockdown. Deletion of Alpha4 in INS-1832/13 cells prevented HG-induced loss in the expression of Connexin36, a gap junction channel protein, which has been implicated in normal beta cell function. Lastly, depletion of endogenous Alpha4 significantly reduced HG-induced cell death in INS-1832/13 cells. Based on these findings we conclude that Alpha4 contributes to HG-induced metabolic dysfunction of the islet beta cell.
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Affiliation(s)
- Mirabela Hali
- Biomedical Research Service, John D. Dingell VA Medical Center, Detroit, MI, USA; Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI, USA
| | - Brian E Wadzinski
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Anjaneyulu Kowluru
- Biomedical Research Service, John D. Dingell VA Medical Center, Detroit, MI, USA; Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI, USA.
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9
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Xu S, Yu W, Zhang X, Wang W, Wang X. The regulatory role of Gnao1 protein in diabetic encephalopathy in KK-Ay mice and streptozotocin-induced diabetic rats. Brain Res 2022; 1792:148012. [PMID: 35839930 DOI: 10.1016/j.brainres.2022.148012] [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: 05/04/2022] [Revised: 07/07/2022] [Accepted: 07/08/2022] [Indexed: 11/02/2022]
Abstract
AIMS To investigate the regulation and functional role of Gnao1 in the brain of diabetic encephalopathy (DE) in various animal models. RESULTS Data from the biochemical and behavioral studies showed that DE models were successful induced in streptozotocin treatment animals and KK-Ay mice. Gnao1 was down regulated in the brain tissues of these two diabetes animal models with significant cognition deficiency. It suggested that the changes in DE are also related to dementia such as Alzheimer's disease (AD). Our study also showed that the expression of adrenergic α2 receptor (Adr-α2R), the upstream protein of Gnao1, was decreased in DE animal models. Furthermore, many downstream proteins of Gnao1 also altered, among which cAMP and PKA proteins were increased, CREB and BDNF proteins were decreased both in animal models and in the cell levels. In addition, Gnao1 silencing leads to the increase of reactive oxygen species (ROS) and the decreased proliferation in cultured primary astrocytes, which means that the deficiency of Gnao1 might not be benefit for DE. CONCLUSION Our findings demonstrated the importance of Gnao1 in DE and suggested Gnao1 as a novel marker and a promising therapeutic target for DE and dementia in animal models.
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Affiliation(s)
- Shuhong Xu
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Department of Pharmacology, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Wenwen Yu
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Department of Pharmacology, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xiang Zhang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Department of Pharmacology, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Weiping Wang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Department of Pharmacology, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xiaoliang Wang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Department of Pharmacology, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
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Yadav Y, Dey CS. Ser/Thr phosphatases: One of the key regulators of insulin signaling. Rev Endocr Metab Disord 2022; 23:905-917. [PMID: 35697962 DOI: 10.1007/s11154-022-09727-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/18/2022] [Indexed: 10/18/2022]
Abstract
Protein phosphorylation is an important post-translational modification that regulates several cellular processes including insulin signaling. The evidences so far have already portrayed the importance of balanced actions of kinases and phosphatases in regulating the insulin signaling cascade. Therefore, elucidating the role of both kinases and phosphatases are equally important. Unfortunately, the role of phosphatases is less studied as compared to kinases. Since brain responds to insulin and insulin signaling is reported to be crucial for many neuronal processes, it is important to understand the role of neuronal insulin signaling regulators. Ser/Thr phosphatases seem to play significant roles in regulating neuronal insulin signaling. Therefore, in this review, we discussed the involvement of Ser/Thr phosphatases in regulating insulin signaling and insulin resistance in neuronal system at the backdrop of the same phosphatases in peripheral insulin sensitive tissues.
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Affiliation(s)
- Yamini Yadav
- Kusuma School of Biological Sciences, Indian Institute of Technology, Delhi, New Delhi, 110016, India
| | - Chinmoy Sankar Dey
- Kusuma School of Biological Sciences, Indian Institute of Technology, Delhi, New Delhi, 110016, India.
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11
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Zhang Y, Wu X, Zhao C, Li K, Zheng Y, Zhao J, Ge P. Integrative Analysis of Whole-genome Expression Profiling and Regulatory Network Identifies Novel Biomarkers for Insulin Resistance in Leptin Receptor-deficient Mice. Med Chem 2021; 16:635-642. [PMID: 31584376 DOI: 10.2174/1573406415666191004135450] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 05/11/2019] [Accepted: 08/23/2019] [Indexed: 11/22/2022]
Abstract
BACKGROUND Molecular characterization of insulin resistance, a growing health issue worldwide, will help to develop novel strategies and accurate biomarkers for disease diagnosis and treatment. OBJECTIVE Integrative analysis of gene expression profiling and gene regulatory network was exploited to identify potential biomarkers early in the development of insulin resistance. METHODS RNA was isolated from livers of animals at three weeks of age, and whole-genome expression profiling was performed and analyzed with Agilent mouse 4×44K microarrays. Differentially expressed genes were subsequently validated by qRT-PCR. Functional characterizations of genes and their interactions were performed by Gene Ontology (GO) analysis and gene regulatory network (GRN) analysis. RESULTS A total of 197 genes were found to be differentially expressed by fold change ≥2 and P < 0.05 in BKS-db +/+ mice relative to sex and age-matched controls. Functional analysis suggested that these differentially expressed genes were enriched in the regulation of phosphorylation and generation of precursor metabolites which are closely associated with insulin resistance. Then a gene regulatory network associated with insulin resistance (IRGRN) was constructed by integration of these differentially expressed genes and known human protein-protein interaction network. The principal component analysis demonstrated that 67 genes in IRGRN could clearly distinguish insulin resistance from the non-disease state. Some of these candidate genes were further experimentally validated by qRT-PCR, highlighting the predictive role as biomarkers in insulin resistance. CONCLUSION Our study provides new insight into the pathogenesis and treatment of insulin resistance and also reveals potential novel molecular targets and diagnostic biomarkers for insulin resistance.
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Affiliation(s)
- Yuchi Zhang
- Department of Pharmacology, School of Basic Medical Sciences, Heilongjiang University of Chinese Medicine, Harbin 150040, China
| | - Xinyu Wu
- Department of Traditional Chinese Medicine, School of Basic Medical Sciences, Heilongjiang University of Chinese Medicine, Harbin 150040, China
| | - Cong Zhao
- Hongqi Hospital Affiliated to Mudanjiang Medical University, Mudanjiang 157011, China
| | - Kai Li
- Harbin Food and Drug Administration, Harbin 150016, China
| | - Yi Zheng
- Chinese People 's Liberation Army Military Economics Institute, Wuhan 430035, China
| | - Jing Zhao
- Department of Pharmacology, School of Basic Medical Sciences, Heilongjiang University of Chinese Medicine, Harbin 150040, China
| | - Pengling Ge
- Department of Pharmacology, School of Basic Medical Sciences, Heilongjiang University of Chinese Medicine, Harbin 150040, China
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12
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Mestareehi A, Zhang X, Seyoum B, Msallaty Z, Mallisho A, Burghardt KJ, Kowluru A, Yi Z. Metformin Increases Protein Phosphatase 2A Activity in Primary Human Skeletal Muscle Cells Derived from Lean Healthy Participants. J Diabetes Res 2021; 2021:9979234. [PMID: 34368369 PMCID: PMC8342103 DOI: 10.1155/2021/9979234] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 07/16/2021] [Indexed: 12/17/2022] Open
Abstract
OBJECTIVE To investigate if PP2A plays a role in metformin-induced insulin sensitivity improvement in human skeletal muscle cells. Participants. Eight lean insulin-sensitive nondiabetic participants (4 females and 4 males; age: 21.0 ± 1.0 years; BMI: 22.0 ± 0.7 kg/m2; 2-hour OGTT: 97.0 ± 6.0 mg/dl; HbA1c: 5.3 ± 0.1%; fasting plasma glucose: 87.0 ± 2.0 mg/dl; M value; 11.0 ± 1.0 mg/kgBW/min). DESIGN A hyperinsulinemic-euglycemic clamp was performed to assess insulin sensitivity in human subjects, and skeletal muscle biopsy samples were obtained. Primary human skeletal muscle cells (shown to retain metabolic characteristics of donors) were cultured from these muscle biopsies that included 8 lean insulin-sensitive participants. Cultured cells were expanded, differentiated into myotubes, and treated with 50 μM metformin for 24 hours before harvesting. PP2Ac activity was measured by a phosphatase activity assay kit (Millipore) according to the manufacturer's protocol. RESULTS The results indicated that metformin significantly increased the activity of PP2A in the myotubes for all 8 lean insulin-sensitive nondiabetic participants, and the average fold increase is 1.54 ± 0.11 (P < 0.001). CONCLUSIONS These results provided the first evidence that metformin can activate PP2A in human skeletal muscle cells derived from lean healthy insulin-sensitive participants and may help to understand metformin's action in skeletal muscle in humans.
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Affiliation(s)
- Aktham Mestareehi
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48201, USA
| | - Xiangmin Zhang
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48201, USA
| | - Berhane Seyoum
- Division of Endocrinology, Wayne State University School of Medicine, Wayne State University, Detroit, MI 48201, USA
| | - Zaher Msallaty
- Division of Endocrinology, Wayne State University School of Medicine, Wayne State University, Detroit, MI 48201, USA
| | - Abdullah Mallisho
- Division of Endocrinology, Wayne State University School of Medicine, Wayne State University, Detroit, MI 48201, USA
| | - Kyle Jon Burghardt
- Department of Pharmacy Practice, Eugene Applebaum College of Pharmacy/Health Sciences, Wayne State University, Detroit, MI, USA
| | - Anjaneyulu Kowluru
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48201, USA
- Program for Translational Research in Diabetes, Biomedical Research Service, John D. Dingell VA Medical Center, Detroit, MI 48201, USA
| | - Zhengping Yi
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48201, USA
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13
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Nguyen LD, Fischer TT, Abreu D, Arroyo A, Urano F, Ehrlich BE. Calpain inhibitor and ibudilast rescue β cell functions in a cellular model of Wolfram syndrome. Proc Natl Acad Sci U S A 2020; 117:17389-17398. [PMID: 32632005 PMCID: PMC7382278 DOI: 10.1073/pnas.2007136117] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Wolfram syndrome is a rare multisystem disease characterized by childhood-onset diabetes mellitus and progressive neurodegeneration. Most cases are attributed to pathogenic variants in a single gene, Wolfram syndrome 1 (WFS1). There currently is no disease-modifying treatment for Wolfram syndrome, as the molecular consequences of the loss of WFS1 remain elusive. Because diabetes mellitus is the first diagnosed symptom of Wolfram syndrome, we aimed to further examine the functions of WFS1 in pancreatic β cells in the context of hyperglycemia. Knockout (KO) of WFS1 in rat insulinoma (INS1) cells impaired calcium homeostasis and protein kinase B/Akt signaling and, subsequently, decreased cell viability and glucose-stimulated insulin secretion. Targeting calcium homeostasis with reexpression of WFS1, overexpression of WFS1's interacting partner neuronal calcium sensor-1 (NCS1), or treatment with calpain inhibitor and ibudilast reversed deficits observed in WFS1-KO cells. Collectively, our findings provide insight into the disease mechanism of Wolfram syndrome and highlight new targets and drug candidates to facilitate the development of a treatment for this disorder and similar diseases.
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Affiliation(s)
- Lien D Nguyen
- Department of Pharmacology, Yale University, New Haven, CT 06520
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06520
| | - Tom T Fischer
- Department of Pharmacology, Yale University, New Haven, CT 06520
- Institute of Pharmacology, University of Heidelberg, 69117 Heidelberg, Germany
| | - Damien Abreu
- Department of Medicine, Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, St. Louis, MO 63110
- Medical Scientist Training Program, Washington University School of Medicine, St. Louis, MO 63110
| | - Alfredo Arroyo
- Department of Pharmacology, Yale University, New Haven, CT 06520
| | - Fumihiko Urano
- Department of Medicine, Division of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, St. Louis, MO 63110
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110
| | - Barbara E Ehrlich
- Department of Pharmacology, Yale University, New Haven, CT 06520;
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06520
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Kowluru A. Potential roles of PP2A-Rac1 signaling axis in pancreatic β-cell dysfunction under metabolic stress: Progress and promise. Biochem Pharmacol 2020; 180:114138. [PMID: 32634437 DOI: 10.1016/j.bcp.2020.114138] [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: 05/18/2020] [Revised: 07/01/2020] [Accepted: 07/02/2020] [Indexed: 12/16/2022]
Abstract
Recent estimates by the International Diabetes Federation suggest that the incidence of diabetes soared to an all-time high of 463 million in 2019, and the federation predicts that by 2045 the number of individuals afflicted with this disease will increase to 700 million. Therefore, efforts to understand the pathophysiology of diabetes are critical for moving toward the development of novel therapeutic strategies for this disease. Several contributors (oxidative stress, endoplasmic reticulum stress and others) have been proposed for the onset of metabolic dysfunction and demise of the islet β-cell leading to the pathogenesis of diabetes. Existing experimental evidence revealed sustained activation of PP2A and Rac1 in pancreatic β-cells exposed to metabolic stress (diabetogenic) conditions. Evidence in a variety of cell types implicates modulatory roles for specific signaling proteins (α4, SET, nm23-H1, Pak1) in the functional regulation of PP2A and Rac1. In this Commentary, I overviewed potential cross-talk between PP2A and Rac1 signaling modules in the onset of metabolic dysregulation of the islet β-cell leading to impaired glucose-stimulated insulin secretion (GSIS), loss of β-cell mass and the onset of diabetes. Potential knowledge gaps and future directions in this fertile area of islet biology are also highlighted. It is hoped that this Commentary will provide a basis for future studies toward a better understanding of roles of PP2A-Rac1 signaling module in pancreatic β-cell dysfunction, and identification of therapeutic targets for the treatment of islet β-cell dysfunction in diabetes.
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Affiliation(s)
- Anjaneyulu Kowluru
- Biomedical Laboratory Research Service, John D. Dingell VA Medical Center and Departments of Pharmaceutical Sciences and Internal Medicine, Wayne State University, Detroit, MI 48201, USA.
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15
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Huang P, Chen K, Ma T, Cao N, Weng D, Xu C, Xu L. The effects of short-term treatment of microcystin-LR on the insulin pathway in both the HL7702 cell line and livers of mice. ENVIRONMENTAL TOXICOLOGY 2020; 35:727-737. [PMID: 32073747 DOI: 10.1002/tox.22907] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 12/07/2019] [Accepted: 01/17/2020] [Indexed: 06/10/2023]
Abstract
Our previous work indicated exposure of Human liver cell 7702 (HL7702) cells to Microcystin-leucine-arginine (MC-LR) for 24 hours can disrupt insulin (INS) signaling by the hyperphosphorylation of specific proteins. For further exploring the time-dependent effect posed by MC-LR on this pathway, in the current study, HL7702 cells together with mice were exposed to the MC-LR with different concentrations under short-term treatment, and then, protein phosphatase 2A (PP2A) activity and expression of proteins related to INS signaling, as well as the characteristics of their action in the liver, were investigated. The results indicated, in HL7702 cells with 0.5, 1, and 6 hours of treatment by MC-LR, PP2A activity showed an obvious decrease in a time and concentration-dependent manner. While the total protein level of Akt, glycogen synthase kinase 3 (GSK-3), and glycogen synthase remained unchanged, GSK-3 and Akt phosphorylation increased significantly. In livers of mice with 1 hour of intraperitoneal injection with MC-LR, a similar change in these proteins was observed. In addition, the levels of total IRS1 and p-IRS1 at serine sites showed decreasing and increasing trends,respectively, and the hematoxylin and eosin staining showed that liver tissues of mice in the maximum-dose group exhibited obvious hepatocyte degeneration and hemorrhage. Our results further proved that short-term treatment with MC-LR can inhibit PP2A activity and disrupt INS signaling proteins' phosphorylation level, thereby interfering with the INS pathway. Our findings provide a helpful understanding of the toxic effects posed by MC-LR on the glucose metabolism of liver via interference with the INS signaling pathway.
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Affiliation(s)
- Pu Huang
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou, China
| | - Kele Chen
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou, China
| | - Tianfeng Ma
- Department I of Clinical Medicine, First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Naifang Cao
- Department I of Clinical Medicine, First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Dengpo Weng
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou, China
| | - Chun Xu
- Department of Endocrinology, The Third Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Lihong Xu
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou, China
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Panicker N, Coutman M, Lawlor-O’Neill C, Kahl RGS, Roselli S, Verrills NM. Ppp2r2a Knockout Mice Reveal That Protein Phosphatase 2A Regulatory Subunit, PP2A-B55α, Is an Essential Regulator of Neuronal and Epidermal Embryonic Development. Front Cell Dev Biol 2020; 8:358. [PMID: 32582689 PMCID: PMC7290052 DOI: 10.3389/fcell.2020.00358] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 04/22/2020] [Indexed: 12/13/2022] Open
Abstract
The serine/threonine protein phosphatase 2A (PP2A) is a master regulator of the complex cellular signaling that occurs during all stages of mammalian development. PP2A is composed of a catalytic, a structural, and regulatory subunit, for which there are multiple isoforms. The association of specific regulatory subunits determines substrate specificity and localization of phosphatase activity, however, the precise role of each regulatory subunit in development is not known. Here we report the generation of the first knockout mouse for the Ppp2r2a gene, encoding the PP2A-B55α regulatory subunit, using CRISPR/Cas9. Heterozygous animals developed and grew as normal, however, homozygous knockout mice were not viable. Analysis of embryos at different developmental stages found a normal Mendelian ratio of Ppp2r2a-/- embryos at embryonic day (E) 10.5 (25%), but reduced Ppp2r2a-/- embryos at E14.5 (18%), and further reduced at E18.5 (10%). No live Ppp2r2a-/- pups were observed at birth. Ppp2r2a-/- embryos were significantly smaller than wild-type or heterozygous littermates and displayed a variety of neural defects such as exencephaly, spina bifida, and cranial vault collapse, as well as syndactyly and severe epidermal defects; all processes driven by growth and differentiation of the ectoderm. Ppp2r2a-/- embryos had incomplete epidermal barrier acquisition, associated with thin, poorly differentiated stratified epithelium with weak attachment to the underlying dermis. The basal keratinocytes in Ppp2r2a-/- embryos were highly disorganized, with reduced immunolabeling of integrins and basement membrane proteins, suggesting impaired focal adhesion and hemidesmosome assembly. The spinous and granular layers were thinner in the Ppp2r2a-/- embryos, with aberrant expression of adherens and tight junction associated proteins. The overlying stratum corneum was either absent or incomplete. Thus PP2A-B55α is an essential regulator of epidermal stratification, and is essential for ectodermal development during embryogenesis.
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Affiliation(s)
- Nikita Panicker
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, Priority Research Centre for Cancer Research, Innovation and Translation, University of Newcastle, Callaghan, NSW, Australia
- Hunter Cancer Research Alliance, Hunter Medical Research Institute, New Lambton, NSW, Australia
| | - Melody Coutman
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, Priority Research Centre for Cancer Research, Innovation and Translation, University of Newcastle, Callaghan, NSW, Australia
- Hunter Cancer Research Alliance, Hunter Medical Research Institute, New Lambton, NSW, Australia
| | - Charley Lawlor-O’Neill
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, Priority Research Centre for Cancer Research, Innovation and Translation, University of Newcastle, Callaghan, NSW, Australia
- Hunter Cancer Research Alliance, Hunter Medical Research Institute, New Lambton, NSW, Australia
| | - Richard G. S. Kahl
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, Priority Research Centre for Cancer Research, Innovation and Translation, University of Newcastle, Callaghan, NSW, Australia
- Hunter Cancer Research Alliance, Hunter Medical Research Institute, New Lambton, NSW, Australia
| | - Séverine Roselli
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, Priority Research Centre for Cancer Research, Innovation and Translation, University of Newcastle, Callaghan, NSW, Australia
- Hunter Cancer Research Alliance, Hunter Medical Research Institute, New Lambton, NSW, Australia
| | - Nicole M. Verrills
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, Priority Research Centre for Cancer Research, Innovation and Translation, University of Newcastle, Callaghan, NSW, Australia
- Hunter Cancer Research Alliance, Hunter Medical Research Institute, New Lambton, NSW, Australia
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Huber KL, Fernández JR, Webb C, Rouzard K, Healy J, Tamura M, Voronkov M, Stock JB, Stock M, Pérez E. HYVIA™: A novel, topical chia seed extract that improves skin hydration. J Cosmet Dermatol 2020; 19:2386-2393. [PMID: 32378329 DOI: 10.1111/jocd.13469] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 04/23/2020] [Accepted: 04/30/2020] [Indexed: 12/31/2022]
Abstract
BACKGROUND Chia seeds have gained importance as it is the highest known plant source of omega-3 (ω3) polyunsaturated fatty acids. Specifically, chia seeds possess ω3 α-linolenic acid (ALA) and ω6 linoleic acid (LA), together known as Vitamin F, which play an important role in maintaining skin function. Protein phosphatase 2A (PP2A) is a master regulatory protein that plays a critical role in skin barrier function and its activity is modulated by natural lipids. AIMS Obtain a chia seed extract (HYVIA™) with significant higher levels of Vitamin F, determine in vitro PP2A activity and skin hydration markers compared to other commercial chia seed extracts (CCSEs), and evaluate the potential skin hydration benefits clinically in human subjects. METHODS A PP2A demethylation assay was utilized to assess PP2A activity. In vitro studies utilizing normal human epidermal keratinocytes (NHEKs) were treated with HYVIA™ and gene expression of hydration markers (AQP3, HAS2) were measured by quantitative PCR (qPCR). A 16-subject clinical trial was performed with 0.1% HYVIA™ formulated in a cream and applied topically to assess its skin moisturizing potential. RESULTS We demonstrate here that HYVIA™, ALA, and LA inhibit PP2A demethylation, boosting PP2A activity, while most other CCSEs do not. Unlike other CCSEs, HYVIA™ increases keratinocyte hydration factors aquaporin-3 and hyaluronic acid synthase-2 in vitro. Clinical assessment of 0.1% HYVIA™ cream shows that HYVIA™ improves skin hydration. CONCLUSIONS HYVIA™ is a novel chia seed extract, enriched for Vitamin F, that modulates PP2A activity and clinically improves skin hydration and barrier function.
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Affiliation(s)
| | | | - Corey Webb
- Signum Biosciences, Monmouth Junction, New Jersey, USA
| | - Karl Rouzard
- Signum Biosciences, Monmouth Junction, New Jersey, USA
| | - Jason Healy
- Signum Biosciences, Monmouth Junction, New Jersey, USA
| | | | | | - Jeffry B Stock
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
| | - Maxwell Stock
- Signum Biosciences, Monmouth Junction, New Jersey, USA
| | - Eduardo Pérez
- Signum Biosciences, Monmouth Junction, New Jersey, USA
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Samet JM, Chen H, Pennington ER, Bromberg PA. Non-redox cycling mechanisms of oxidative stress induced by PM metals. Free Radic Biol Med 2020; 151:26-37. [PMID: 31877355 PMCID: PMC7803379 DOI: 10.1016/j.freeradbiomed.2019.12.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Revised: 12/13/2019] [Accepted: 12/20/2019] [Indexed: 12/27/2022]
Abstract
Metallic compounds contribute to the oxidative stress of ambient particulate matter (PM) exposure. The toxicity of redox inert ions of cadmium, mercury, lead and zinc, as well as redox-active ions of vanadium and chromium is underlain by dysregulation of mitochondrial function and loss of signaling quiescence. Central to the initiation of these effects is the interaction of metal ions with cysteinyl thiols on glutathione and key regulatory proteins, which leads to impaired mitochondrial electron transport and persistent pan-activation of signal transduction pathways. The mitochondrial and signaling effects are linked by the production of H2O2, generated from mitochondrial superoxide anion or through the activation of NADPH oxidase, which extends the range and amplifies the magnitude of the oxidative effects of the metals. This oxidative burden can be further potentiated by inhibitory effects of the metals on the enzymes of the glutathione and thioredoxin systems. Along with the better-known Fenton-based mechanisms, the non-redox cycling mechanisms of oxidative stress induced by metals constitute significant pathways for cellular injury induced by PM inhalation.
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Affiliation(s)
- James M Samet
- Environmental Public Health Division, Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Chapel Hill, NC, USA.
| | - Hao Chen
- Oak Ridge Institute for Science and Education, Oak Ridge, TN, USA
| | | | - Philip A Bromberg
- Center for Environmental Medicine, Asthma and Lung Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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19
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Patel BM, Goyal RK. Liver and insulin resistance: New wine in old bottle!!! Eur J Pharmacol 2019; 862:172657. [DOI: 10.1016/j.ejphar.2019.172657] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 09/02/2019] [Accepted: 09/05/2019] [Indexed: 12/20/2022]
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20
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Zhong Y, Lee K, Deng Y, Ma Y, Chen Y, Li X, Wei C, Yang S, Wang T, Wong NJ, Muwonge AN, Azeloglu EU, Zhang W, Das B, He JC, Liu R. Arctigenin attenuates diabetic kidney disease through the activation of PP2A in podocytes. Nat Commun 2019; 10:4523. [PMID: 31586053 PMCID: PMC6778111 DOI: 10.1038/s41467-019-12433-w] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 09/10/2019] [Indexed: 12/20/2022] Open
Abstract
Arctigenin (ATG) is a major component of Fructus Arctii, a traditional herbal remedy that reduced proteinuria in diabetic patients. However, whether ATG specifically provides renoprotection in DKD is not known. Here we report that ATG administration is sufficient to attenuate proteinuria and podocyte injury in mouse models of diabetes. Transcriptomic analysis of diabetic mouse glomeruli showed that cell adhesion and inflammation are two key pathways affected by ATG treatment, and mass spectrometry analysis identified protein phosphatase 2 A (PP2A) as one of the top ATG-interacting proteins in renal cells. Enhanced PP2A activity by ATG reduces p65 NF-κB-mediated inflammatory response and high glucose-induced migration in cultured podocytes via interaction with Drebrin-1. Importantly, podocyte-specific Pp2a deletion in mice exacerbates DKD injury and abrogates the ATG-mediated renoprotection. Collectively, our results demonstrate a renoprotective mechanism of ATG via PP2A activation and establish PP2A as a potential target for DKD progression.
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Affiliation(s)
- Yifei Zhong
- Department of Nephrology, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
| | - Kyung Lee
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Yueyi Deng
- Department of Nephrology, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Yueming Ma
- Department of Pharmacology, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China
| | - Yiping Chen
- Department of Nephrology, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Xueling Li
- Department of Nephrology, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Chengguo Wei
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Shumin Yang
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Tianming Wang
- Department of Pharmacology, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China
| | - Nicholas J Wong
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Alecia N Muwonge
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Evren U Azeloglu
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Weijia Zhang
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Bhaskar Das
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - John Cijiang He
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
- Renal Section, James J Peters Veterans Affair Medical Center, Bronx, NY, USA.
| | - Ruijie Liu
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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Physiologic functions of PP2A: Lessons from genetically modified mice. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1866:31-50. [DOI: 10.1016/j.bbamcr.2018.07.010] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 07/11/2018] [Accepted: 07/14/2018] [Indexed: 01/03/2023]
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22
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Yin J, Ren W, Chen S, Li Y, Han H, Gao J, Liu G, Wu X, Li T, Woo Kim S, Yin Y. Metabolic Regulation of Methionine Restriction in Diabetes. Mol Nutr Food Res 2018; 62:e1700951. [PMID: 29603632 DOI: 10.1002/mnfr.201700951] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Revised: 01/25/2018] [Indexed: 12/16/2022]
Abstract
Although the effects of dietary methionine restriction have been investigated in the physiology of aging and diseases related to oxidative stress, the relationship between methionine restriction (MR) and the development of metabolic disorders has not been explored extensively. This review summarizes studies of the possible involvement of dietary methionine restriction in improving insulin resistance, glucose homeostasis, oxidative stress, lipid metabolism, the pentose phosphate pathway (PPP), and inflammation, with an emphasis on the fibroblast growth factor 21 and protein phosphatase 2A signals and autophagy in diabetes. Diets deficient in methionine may be a useful nutritional strategy in patients with diabetes.
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Affiliation(s)
- Jie Yin
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, Institute of Subtropical Animal Nutrition and Feed, College of Animal Science, South China Agricultural University, Guangzhou, China.,Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China.,University of Chinese Academy of Sciences, Beijing, PR, China
| | - Wenkai Ren
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, Institute of Subtropical Animal Nutrition and Feed, College of Animal Science, South China Agricultural University, Guangzhou, China.,Jiangsu Co-Innovation Center for Important Animal Infectious Diseases and Zoonoses, Joint International Research Laboratory of Agriculture and Agri-Product, Safety of Ministry of Education of China, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Shuai Chen
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China.,University of Chinese Academy of Sciences, Beijing, PR, China
| | - Yuying Li
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China.,University of Chinese Academy of Sciences, Beijing, PR, China
| | - Hui Han
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China.,University of Chinese Academy of Sciences, Beijing, PR, China
| | - Jing Gao
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China.,University of Chinese Academy of Sciences, Beijing, PR, China
| | - Gang Liu
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China
| | - Xin Wu
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China.,Hunan Co-Innovation Center of Animal Production Safety, Changsha, PR, China
| | - Tiejun Li
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China.,Hunan Co-Innovation Center of Animal Production Safety, Changsha, PR, China
| | - Sung Woo Kim
- Department of Animal Science, North Carolina State University, Raleigh, NC, USA
| | - Yulong Yin
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, Institute of Subtropical Animal Nutrition and Feed, College of Animal Science, South China Agricultural University, Guangzhou, China.,Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China.,Hunan Co-Innovation Center of Animal Production Safety, Changsha, PR, China
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23
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Miraee-Nedjad S, Sims PFG, Schwartz JM, Doig AJ. Effect of IAPP on the proteome of cultured Rin-5F cells. BMC BIOCHEMISTRY 2018; 19:9. [PMID: 30419808 PMCID: PMC6233276 DOI: 10.1186/s12858-018-0099-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 10/22/2018] [Indexed: 11/12/2022]
Abstract
Background Islet amyloid polypeptide (IAPP) or amylin deposits can be found in the islets of type 2 diabetes patients. The peptide is suggested to be involved in the etiology of the disease through formation of amyloid deposits and destruction of β islet cells, though the underlying molecular events leading from IAPP deposition to β cell death are still largely unknown. Results We used OFFGEL™ proteomics to study how IAPP exposure affects the proteome of rat pancreatic insulinoma Rin-5F cells. The OFFGEL™ methodology is highly effective at generating quantitative data on hundreds of proteins affected by IAPP, with its accuracy confirmed by In Cell Western and Quantitative Real Time PCR results. Combining data on individual proteins identifies pathways and protein complexes affected by IAPP. IAPP disrupts protein synthesis and degradation, and induces oxidative stress. It causes decreases in protein transport and localization. IAPP disrupts the regulation of ubiquitin-dependent protein degradation and increases catabolic processes. IAPP causes decreases in protein transport and localization, and affects the cytoskeleton, DNA repair and oxidative stress. Conclusions Results are consistent with a model where IAPP aggregates overwhelm the ability of a cell to degrade proteins via the ubiquitin system. Ultimately this leads to apoptosis. IAPP aggregates may be also toxic to the cell by causing oxidative stress, leading to DNA damage or by decreasing protein transport. The reversal of any of these effects, perhaps by targeting proteins which alter in response to IAPP, may be beneficial for type II diabetes. Electronic supplementary material The online version of this article (10.1186/s12858-018-0099-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Samaneh Miraee-Nedjad
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - Paul F G Sims
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK
| | - Jean-Marc Schwartz
- Division of Evolution & Genomic Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK
| | - Andrew J Doig
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK.
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24
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Mazhar S, Taylor SE, Sangodkar J, Narla G. Targeting PP2A in cancer: Combination therapies. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1866:51-63. [PMID: 30401535 DOI: 10.1016/j.bbamcr.2018.08.020] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 08/21/2018] [Accepted: 08/28/2018] [Indexed: 12/12/2022]
Abstract
The serine/threonine phosphatase PP2A regulates a vast portion of the phosphoproteome including pathways involved in apoptosis, proliferation and DNA damage response and PP2A inactivation is a vital step in malignant transformation. Many groups have explored the therapeutic venue of combining PP2A reactivation with kinase inhibition to counteract the very changes in tumor suppressors and oncogenes that lead to cancer development. Conversely, inhibition of PP2A to complement chemotherapy and radiation-induced cancer cell death is also an area of active investigation. Here we review the studies that utilize PP2A targeted agents as combination therapy in cancer. A potential role for PP2A in tumor immunity is also highlighted.
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Affiliation(s)
- Sahar Mazhar
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Sarah E Taylor
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Jaya Sangodkar
- Division of Genetic Medicine, Michigan Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Goutham Narla
- Division of Genetic Medicine, Michigan Medicine, University of Michigan, Ann Arbor, MI, USA.
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25
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Kowluru A, Kowluru RA. RACking up ceramide-induced islet β-cell dysfunction. Biochem Pharmacol 2018; 154:161-169. [PMID: 29715450 DOI: 10.1016/j.bcp.2018.04.026] [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: 03/30/2018] [Accepted: 04/27/2018] [Indexed: 12/20/2022]
Abstract
The International Diabetes Federation predicts that by 2045 the number of individuals afflicted with diabetes will increase to 629 million. Furthermore, ∼352 million individuals with impaired glucose tolerance are at increased risk for developing diabetes. Several mechanisms have been proposed for the onset of metabolic dysfunction and demise of the islet β-cell leading to the pathogenesis of diabetes. It is widely accepted that the onset of type 2 diabetes is due to an intricate interplay between genetic expression of the disease and a multitude of factors including increased oxidative and endoplasmic reticulum stress consequential to glucolipotoxicity and inflammation. Compelling experimental evidence from in vitro and in vivo studies implicates intracellular generation of ceramide (CER), a biologically-active sphingolipid, as a trigger in the onset of β-cell demise under above pathological conditions. Recent pharmacological and molecular biological evidence affirms regulatory roles for Ras-related C3 botulinum toxin substrate 1 (Rac1), a small G protein, in the islet β-cell function in health and diabetes. In this Commentary, we overviewed the emerging evidence implicating potential cross-talk between Rac1 and ceramide signaling pathways in the onset of metabolic dysregulation of the islet β-cell culminating in impaired physiological insulin secretion, loss of β-cell mass and the onset of diabetes. Further, we propose a model depicting contributory roles of defective protein lipidation (prenylation) pathway in the induction of metabolic defects in the β-cell under metabolic stress conditions. Potential avenues for the identification of novel therapeutic targets for the prevention/treatment of diabetes and its associated complications are highlighted.
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Affiliation(s)
- Anjaneyulu Kowluru
- Biomedical Research Service, John D. Dingell VA Medical Center, Wayne State University, Detroit, MI 48201, USA; Department of Pharmaceutical Sciences, Wayne State University, Detroit, MI 48201, USA.
| | - Renu A Kowluru
- Department of Ophthalmology and Anatomy and Cell Biology, Wayne State University, Detroit, MI 48201, USA
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26
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Guo J, Li C, Yang C, Li B, Wei J, Lin Y, Ye P, Hu G, Li J. Liraglutide reduces hepatic glucolipotoxicity‑induced liver cell apoptosis through NRF2 signaling in Zucker diabetic fatty rats. Mol Med Rep 2018; 17:8316-8324. [PMID: 29693190 PMCID: PMC5984007 DOI: 10.3892/mmr.2018.8919] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 04/17/2018] [Indexed: 12/30/2022] Open
Abstract
The primary aim of the present study was to evaluate the effects of liraglutide on glucolipotoxicity-induced liver cell apoptosis and the underlying mechanisms in Zucker diabetic fatty (ZDF) rats. The results revealed that liraglutide significantly decreased the body weight, hyperglycemia and hyperlipidemia of ZDF rats relative to those of Zucker lean (ZL) rats (P<0.05). Furthermore, the reduced liver cell apoptosis was observed in the ZDF rats following 6 weeks of liraglutide therapy. These data validated the beneficial effects of liraglutide on diabetic and obese ZDF rats. In addition, novel data was obtained that demonstrated that liraglutide treatment increased the expression of the antioxidant transcription factor nuclear factor-erythroid 2-related factor 2 (NRF2), as well as the transcription of downstream target genes, including nicotinamide adenine dinucleotide phosphate quinone dehydrogenase 1 and heme oxygenase-1 (P<0.05). Additionally, serum and hepatic GSH and SOD levels increased following liraglutide therapy (P<0.05). Hence, it was proposed that liraglutide may enhance the antioxidant activity of liver cells by activating the NRF2 signaling pathway, thereby reducing liver cell apoptosis induced by glucolipotoxicity in ZDF rats, which may shed light on the application of liraglutide in the treatment of diabetes- and obesity-induced liver injury.
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Affiliation(s)
- Jun Guo
- The MOH Key Laboratory of Geriatrics, Beijing Hospital, National Center of Gerontology, Beijing 100730, P.R. China
| | - Cai Li
- The MOH Key Laboratory of Geriatrics, Beijing Hospital, National Center of Gerontology, Beijing 100730, P.R. China
| | - Chunxiao Yang
- The MOH Key Laboratory of Geriatrics, Beijing Hospital, National Center of Gerontology, Beijing 100730, P.R. China
| | - Bing Li
- Department of Encephalopathy, Medical Department of Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, Shandong 250355, P.R. China
| | - Jie Wei
- The MOH Key Laboratory of Geriatrics, Beijing Hospital, National Center of Gerontology, Beijing 100730, P.R. China
| | - Yajun Lin
- The MOH Key Laboratory of Geriatrics, Beijing Hospital, National Center of Gerontology, Beijing 100730, P.R. China
| | - Peng Ye
- The MOH Key Laboratory of Geriatrics, Beijing Hospital, National Center of Gerontology, Beijing 100730, P.R. China
| | - Gang Hu
- The MOH Key Laboratory of Geriatrics, Beijing Hospital, National Center of Gerontology, Beijing 100730, P.R. China
| | - Jian Li
- The MOH Key Laboratory of Geriatrics, Beijing Hospital, National Center of Gerontology, Beijing 100730, P.R. China
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27
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Rieusset J. The role of endoplasmic reticulum-mitochondria contact sites in the control of glucose homeostasis: an update. Cell Death Dis 2018. [PMID: 29523782 PMCID: PMC5844895 DOI: 10.1038/s41419-018-0416-1] [Citation(s) in RCA: 154] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The contact sites that the endoplasmic reticulum (ER) forms with mitochondria, called mitochondria-associated membranes (MAMs), are a hot topic in biological research, and both their molecular determinants and their numerous roles in several signaling pathways are is continuously evolving. MAMs allow the exchange between both organelles of lipids, calcium (Ca2+), and likely reactive oxygen species, allowing adaptations of both cellular bioenergetics and cell fate depending of cellular needs or stresses. Therefore, it is not surprising that MAMs affect cellular metabolism. Nevertheless, recent arguments suggest that MAMs could also act as key hub of hormonal and/or nutrient signaling in several insulin-sensitive tissues, pointing a specific role of MAMs in the control of glucose homeostasis. Here, I provide a brief review and update on current key signaling roles of the MAMs in the control of glucose homeostasis in both health and metabolic diseases. Particularly, the relevance of ER-mitochondria miscommunication in the disruption of glucose homeostasis is analyzed in details in the liver, skeletal muscle, adipose tissue, and beta cells of the pancreas.
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Affiliation(s)
- Jennifer Rieusset
- Laboratoire CarMeN, Unité Mixte de Recherche INSERM U-1060 et INRA U-1397, Université Lyon 1, Oullins, 69600, France.
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28
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Mirra P, Nigro C, Prevenzano I, Leone A, Raciti GA, Formisano P, Beguinot F, Miele C. The Destiny of Glucose from a MicroRNA Perspective. Front Endocrinol (Lausanne) 2018; 9:46. [PMID: 29535681 PMCID: PMC5834423 DOI: 10.3389/fendo.2018.00046] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Glucose serves as a primary, and for some tissues the unique, fuel source in order to generate and maintain the biological functions. Hyperglycemia is a hallmark of type 2 diabetes and is the direct consequence of perturbations in the glucose homeostasis. Insulin resistance, referred to as a reduced response of target tissues to the hormone, contributes to the development of hyperglycemia. The molecular mechanisms responsible for the altered glucose homeostasis are numerous and not completely understood. MicroRNAs (miRNAs) are now recognized as regulators of the lipid and glucose metabolism and are involved in the onset of metabolic diseases. Indeed, these small non-coding RNA molecules operate in the RNA silencing and posttranscriptional regulation of gene expression and may modulate the levels of kinases and enzymes in the glucose metabolism. Therefore, a better characterization of the function of miRNAs and a deeper understanding of their role in disease may represent a fundamental step toward innovative treatments addressing the causes, not only the symptoms, of hyperglycemia, using approaches aimed at restoring either miRNAs or their specific targets. In this review, we outline the current understanding regarding the impact of miRNAs in the glucose metabolism and highlight the need for further research focused on altered key kinases and enzymes in metabolic diseases.
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Affiliation(s)
- Paola Mirra
- Istituto per l’Endocrinologia e l’Oncologia Sperimentale “Gaetano Salvatore” - CNR, Naples, Italy
- Department of Translational Medical Sciences, University of Naples Federico II, Naples, Italy
| | - Cecilia Nigro
- Istituto per l’Endocrinologia e l’Oncologia Sperimentale “Gaetano Salvatore” - CNR, Naples, Italy
- Department of Translational Medical Sciences, University of Naples Federico II, Naples, Italy
| | - Immacolata Prevenzano
- Istituto per l’Endocrinologia e l’Oncologia Sperimentale “Gaetano Salvatore” - CNR, Naples, Italy
- Department of Translational Medical Sciences, University of Naples Federico II, Naples, Italy
| | - Alessia Leone
- Istituto per l’Endocrinologia e l’Oncologia Sperimentale “Gaetano Salvatore” - CNR, Naples, Italy
- Department of Translational Medical Sciences, University of Naples Federico II, Naples, Italy
| | - Gregory Alexander Raciti
- Istituto per l’Endocrinologia e l’Oncologia Sperimentale “Gaetano Salvatore” - CNR, Naples, Italy
- Department of Translational Medical Sciences, University of Naples Federico II, Naples, Italy
| | - Pietro Formisano
- Istituto per l’Endocrinologia e l’Oncologia Sperimentale “Gaetano Salvatore” - CNR, Naples, Italy
- Department of Translational Medical Sciences, University of Naples Federico II, Naples, Italy
| | - Francesco Beguinot
- Istituto per l’Endocrinologia e l’Oncologia Sperimentale “Gaetano Salvatore” - CNR, Naples, Italy
- Department of Translational Medical Sciences, University of Naples Federico II, Naples, Italy
| | - Claudia Miele
- Istituto per l’Endocrinologia e l’Oncologia Sperimentale “Gaetano Salvatore” - CNR, Naples, Italy
- Department of Translational Medical Sciences, University of Naples Federico II, Naples, Italy
- *Correspondence: Claudia Miele,
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29
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Energy depletion and not ROS formation is a crucial step of glucolipotoxicity (GLTx) in pancreatic beta cells. Pflugers Arch 2017; 470:537-547. [PMID: 29218453 DOI: 10.1007/s00424-017-2094-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 11/30/2017] [Indexed: 12/27/2022]
Abstract
We have shown previously that genetic or pharmacological deletion of KATP channels protect against beta cell dysfunction induced by reactive oxygen species (ROS). Since it is assumed that glucolipotoxicity (GLTx) causes ROS production, we aimed to evaluate whether suppression of KATP channel activity can also prevent beta cell damage evoked by GLTx. We used an in vitro model of GLTx and measured distinct parameters of stimulus-secretion coupling. GLTx gradually induced disturbances of Ca2+ oscillations over 3 days. This impairment in Ca2+ dynamics was partially reversed in beta cells without functional KATP channels (SUR1-/-) and by the sulfonylurea gliclazide but not by tolbutamide. By contrast, the GLTx-induced suppression of glucose-induced insulin secretion could not be rescued by decreased KATP channel activity pointing to a direct interaction of GLTx with the secretory capacity. Accordingly, GLTx also suppressed KCl-induced insulin secretion. GLTx was not accompanied by decisively increased ROS production or enhanced apoptosis. Insulin content of beta cells was markedly reduced by GLTx, an effect not prevented by gliclazide. Since GLTx markedly diminished the mitochondrial membrane potential and cellular ATP content, lack of ATP is assumed to decrease insulin biosynthesis. The deleterious effect of GLTx is therefore caused by direct interference with the secretory capacity whereby reduction of insulin content is one important parameter. These findings deepen our understanding how GLTx damages beta cells and reveal that GLTx is disconnected from ROS formation, a notion important for targeting beta cells in the treatment of diabetes. Overall, GLTx-induced energy depletion may be a primary step in the cascade of events leading to loss of beta cell function in type-2 diabetes mellitus.
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30
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Wang B, Liu J, Huang P, Xu K, Wang H, Wang X, Guo Z, Xu L. Protein phosphatase 2A inhibition and subsequent cytoskeleton reorganization contributes to cell migration caused by microcystin-LR in human laryngeal epithelial cells (Hep-2). ENVIRONMENTAL TOXICOLOGY 2017; 32:890-903. [PMID: 27393157 DOI: 10.1002/tox.22289] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 05/08/2016] [Accepted: 05/08/2016] [Indexed: 06/06/2023]
Abstract
The major toxic mechanism of Microcystin-LR is inhibition of the activity of protein phosphatase 2A (PP2A), resulting in a series of cytotoxic effects. Our previous studies have demonstrated that microcystin-LR (MCLR) induced very different molecular effects in normal cells and the tumor cell line SMMC7721. To further explore the MCLR toxicity mechanism in tumor cells, human laryngeal epithelial cells (Hep-2) was examined in this study. Western blot, immunofluorescence, immunoprecipitation, and transwell migration assay were used to detect the effects of MCLR on PP2A activity, PP2A substrates, cytoskeleton, and cell migration. The results showed that the protein level of PP2A subunits and the posttranslational modification of the catalytic subunit were altered and that the binding of the AC core enzyme as well as the binding of PP2A/C and α4, was also affected. As PP2A substrates, the phosphorylation of MAPK pathway members, p38, ERK1/2, and the cytoskeleton-associated proteins, Hsp27, VASP, Tau, and Ezrin were increased. Furthermore, MCLR induced reorganization of the cytoskeleton and promoted cell migration. Taken together, direct covalent binding to PP2A/C, alteration of the protein levels and posttranslational modification, as well as the binding of subunits, are the main pattern for the effects of MCLR on PP2A in Hep-2. A dose-dependent change in p-Tau and p-Ezrin due to PP2A inhibition may contribute to the changes in the cytoskeleton and be related to the cell migration in Hep-2. Our data provide a comprehensive exposition of the MCLR mechanism on tumor cells. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 890-903, 2017.
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Affiliation(s)
- Beilei Wang
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou, 310058, China
| | - Jinghui Liu
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou, 310058, China
| | - Pu Huang
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou, 310058, China
| | - Kailun Xu
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou, 310058, China
| | - Hanying Wang
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou, 310058, China
| | - Xiaofeng Wang
- Zhejiang Center for Disease Control and Prevention, Hangzhou, 310051, China
| | - Zonglou Guo
- Department of Biosystem Engineering, College of Biosystem Engineering and Food Science, Zhejiang University, Hangzhou, 310058, China
| | - Lihong Xu
- Department of Biochemistry, School of Medicine, Zhejiang University, Hangzhou, 310058, China
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31
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Tubbs E, Rieusset J. Metabolic signaling functions of ER-mitochondria contact sites: role in metabolic diseases. J Mol Endocrinol 2017; 58:R87-R106. [PMID: 27965371 DOI: 10.1530/jme-16-0189] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 12/13/2016] [Indexed: 12/16/2022]
Abstract
Beyond the maintenance of cellular homeostasis and the determination of cell fate, ER-mitochondria contact sites, defined as mitochondria-associated membranes (MAM), start to emerge as an important signaling hub that integrates nutrient and hormonal stimuli and adapts cellular metabolism. Here, we summarize the established structural and functional features of MAM and mainly focus on the latest breakthroughs highlighting a crucial role of organelle crosstalk in the control of metabolic homeostasis. Lastly, we discuss recent studies that have revealed the importance of MAM in not only metabolic diseases but also in other pathologies with disrupted metabolism, shedding light on potential common molecular mechanisms and leading hopefully to novel treatment strategies.
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Affiliation(s)
- Emily Tubbs
- Department of Clinical SciencesLund University Diabetes Centre, Malmö, Sweden
| | - Jennifer Rieusset
- INSERM UMR-1060CarMeN Laboratory, Lyon 1 University, INRA U1235, INSA of Lyon, Charles Merieux Lyon-Sud medical Universities, Lyon, France
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32
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Rieusset J. Endoplasmic reticulum-mitochondria calcium signaling in hepatic metabolic diseases. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:865-876. [PMID: 28064001 DOI: 10.1016/j.bbamcr.2017.01.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 12/21/2016] [Accepted: 01/02/2017] [Indexed: 02/07/2023]
Abstract
The liver plays a central role in glucose homeostasis, and both metabolic inflexibility and insulin resistance predispose to the development of hepatic metabolic diseases. Mitochondria and endoplasmic reticulum (ER), which play a key role in the control of hepatic metabolism, also interact at contact points defined as mitochondria-associated membranes (MAM), in order to exchange metabolites and calcium (Ca2+) and regulate cellular homeostasis and signaling. Here, we overview the role of the liver in the control of glucose homeostasis, mainly focusing on the independent involvement of mitochondria, ER and Ca2+ signaling in both healthy and pathological contexts. Then we focus on recent data highlighting MAM as important hubs for hormone and nutrient signaling in the liver, thus adapting mitochondria physiology and cellular metabolism to energy availability. Lastly, we discuss how chronic ER-mitochondria miscommunication could participate to hepatic metabolic diseases, pointing MAM interface as a potential therapeutic target for metabolic disorders. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.
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Affiliation(s)
- Jennifer Rieusset
- INSERM UMR-1060, CarMeN Laboratory, Lyon 1 University, INRA U1397, F-69921 Oullins, France.
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33
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Theurey P, Rieusset J. Mitochondria-Associated Membranes Response to Nutrient Availability and Role in Metabolic Diseases. Trends Endocrinol Metab 2017; 28:32-45. [PMID: 27670636 DOI: 10.1016/j.tem.2016.09.002] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 08/31/2016] [Accepted: 09/01/2016] [Indexed: 12/13/2022]
Abstract
Metabolic diseases are associated with nutrient excess and metabolic inflexibility. Mitochondria and endoplasmic reticulum are important organelles and nutrient sensors, and their dysfunction has been extensively and independently implicated in metabolic diseases. Both organelles interact at sites known as mitochondria-associated membranes (MAMs), in order to exchange metabolites and calcium. Recent evidence indicates that MAM could be a hub of hepatic insulin signaling and nutrient sensing. In this review, we discuss the roles organelle function and communication play in the cell's adaptation to nutrient availability, in both physiology and metabolic diseases. We highlight how dynamic regulation of MAM affects mitochondria physiology and adaptation of cellular metabolism to nutrient availability, and how chronic MAM disruption participates in the metabolic inflexibility associated with metabolic disorders.
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Affiliation(s)
- Pierre Theurey
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Jennifer Rieusset
- INSERM UMR-1060, CarMeN Laboratory, Lyon 1 University, INRA U1397, F-69921 Oullins, France.
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Role of Endoplasmic Reticulum-Mitochondria Communication in Type 2 Diabetes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 997:171-186. [DOI: 10.1007/978-981-10-4567-7_13] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Beg M, Srivastava A, Shankar K, Varshney S, Rajan S, Gupta A, Kumar D, Gaikwad AN. PPP2R5B, a regulatory subunit of PP2A, contributes to adipocyte insulin resistance. Mol Cell Endocrinol 2016; 437:97-107. [PMID: 27521959 DOI: 10.1016/j.mce.2016.08.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 07/04/2016] [Accepted: 08/09/2016] [Indexed: 12/29/2022]
Abstract
Insulin resistance is associated with deregulation of insulin signaling owing to the chronic exposure of insulin (hyperinsulinemia) to the tissues. Phosphorylation and dephosphorylation events in insulin signaling pathway play an essential role in signal transduction and glucose uptake. Amongst all, Akt protein is considered to be central to the overall insulin signaling proteins. In glucose responsive tissues like adipose and muscles, activation of Akt is responsible for triggering GLUT4 translocation and glucose transport. Several phosphatases such as PTEN, PP2A have been reported to be involved in dephosphorylation and inactivation of Akt protein. We have identified increased PP2A activity during state of chronic hyperinsulinemia exposure along-with development of adipocyte insulin resistance. This increased phosphatase activity leads activation of cAMP/PKA axis, which in turn increased cAMP levels in insulin resistant (IR) adipocytes. Okadaic acid, an inhibitor of PP2A restored and increased insulin stimulated glucose uptake in insulin resistant (IR) and insulin sensitive (IS) adipocytes respectively. In IS adipocyte, chemical activation of PP2A through MG132 and FTY720 showed decreased insulin sensitivity corroborated with decreased Akt phosphorylation and glucose uptake. We also observed an increased expression of PP2A-B (regulatory) subunit in IR adipocytes. We found PPP2R5B, a regulatory subunit of PP2A is responsible for the dephosphorylation and inactivation of Akt protein. Increased expression of PPP2R5B was also confirmed in white adipose tissue of high fat diet induced IR mice model. Overexpression and suppression strategies confirmed the role of PPP2R5B in regulating insulin signaling. Thus, we conclude that PPP2R5B, a B subunit of PP2A is a negative regulator of Akt phosphorylation contributing partly to the chronic hyperinsulinemia induced insulin resistance in adipocytes.
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Affiliation(s)
- Muheeb Beg
- Division of Pharmacology, CSIR-Central Drug Research Institute, Lucknow, 226031, India
| | - Ankita Srivastava
- Division of Pharmacology, CSIR-Central Drug Research Institute, Lucknow, 226031, India; Academy of Scientific and Innovative Research, CSIR-CDRI, India
| | - Kripa Shankar
- Division of Pharmacology, CSIR-Central Drug Research Institute, Lucknow, 226031, India
| | - Salil Varshney
- Division of Pharmacology, CSIR-Central Drug Research Institute, Lucknow, 226031, India
| | - Sujith Rajan
- Division of Pharmacology, CSIR-Central Drug Research Institute, Lucknow, 226031, India; Academy of Scientific and Innovative Research, CSIR-CDRI, India
| | - Abhishek Gupta
- Division of Pharmacology, CSIR-Central Drug Research Institute, Lucknow, 226031, India
| | - Durgesh Kumar
- Division of Pharmacology, CSIR-Central Drug Research Institute, Lucknow, 226031, India; Academy of Scientific and Innovative Research, CSIR-CDRI, India
| | - Anil N Gaikwad
- Division of Pharmacology, CSIR-Central Drug Research Institute, Lucknow, 226031, India; Academy of Scientific and Innovative Research, CSIR-CDRI, India.
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Abstract
Insulin resistance is a systemic disorder that affects many organs and insulin-regulated pathways. The disorder is characterized by a reduced action of insulin despite increased insulin concentrations (hyperinsulinaemia). The effects of insulin on the kidney and vasculature differ in part from the effects on classical insulin target organs. Insulin causes vasodilation by enhancing endothelial nitric oxide production through activation of the phosphatidylinositol 3-kinase pathway. In insulin-resistant states, this pathway is impaired and the mitogen-activated protein kinase pathway stimulates vasoconstriction. The action of insulin on perivascular fat tissue and the subsequent effects on the vascular wall are not fully understood, but the hepatokine fetuin-A, which is released by fatty liver, might promote the proinflammatory effects of perivascular fat. The strong association of salt-sensitive arterial hypertension with insulin resistance indicates an involvement of the kidney in the insulin resistance syndrome. The insulin receptor is expressed on renal tubular cells and podocytes and insulin signalling has important roles in podocyte viability and tubular function. Renal sodium transport is preserved in insulin resistance and contributes to the salt-sensitivity of blood pressure in hyperinsulinaemia. Therapeutically, renal and vascular insulin resistance can be improved by an integrated holistic approach aimed at restoring overall insulin sensitivity and improving insulin signalling.
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Boal F, Timotin A, Roumegoux J, Alfarano C, Calise D, Anesia R, Parini A, Valet P, Tronchere H, Kunduzova O. Apelin-13 administration protects against ischaemia/reperfusion-mediated apoptosis through the FoxO1 pathway in high-fat diet-induced obesity. Br J Pharmacol 2016; 173:1850-63. [PMID: 27005319 PMCID: PMC4867747 DOI: 10.1111/bph.13485] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 02/02/2016] [Accepted: 02/28/2016] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND AND PURPOSE Apelin-13, an endogenous ligand for the apelin (APJ) receptor, behaves as a potent modulator of metabolic and cardiovascular disorders. Here, we examined the effects of apelin-13 on myocardial injury in a mouse model combining ischaemia/reperfusion (I/R) and obesity and explored their underlying mechanisms. EXPERIMENTAL APPROACH Adult male C57BL/6J mice were fed a normal diet (ND) or high-fat diet (HFD) for 6 months and then subjected to cardiac I/R. The effects of apelin-13 post-treatment on myocardial injury were evaluated in HFD-fed mice after 24 h I/R. Changes in protein abundance, phosphorylation, subcellular localization and mRNA expression were determined in cardiomyoblast cell line H9C2, primary cardiomyocytes and cardiac tissue from ND- and HFD-fed mice. Apoptosis was evaluated by TUNEL staining and caspase-3 activity. Mitochondrial ultrastructure was analysed by electron microscopy. KEY RESULTS In HFD-fed mice subjected to cardiac I/R, i.v. administration of apelin-13 significantly reduced infarct size, myocardial apoptosis and mitochondrial damage compared with vehicle-treated animals. In H9C2 cells and primary cardiomyocytes, apelin-13 induced FoxO1 phosphorylation and nuclear exclusion. FoxO1 silencing by siRNA abolished the protective effects of apelin-13 against hypoxia-induced apoptosis and mitochondrial ROS generation. Finally, apelin deficiency in mice fed a HFD resulted in reduced myocardial FoxO1 expression and impaired FoxO1 distribution. CONCLUSIONS AND IMPLICATIONS These data reveal apelin as a novel regulator of FoxO1 in cardiac cells and provide evidence for the potential of apelin-13 in prevention of apoptosis and mitochondrial damage in conditions combining I/R injury and obesity.
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Affiliation(s)
- Frederic Boal
- National Institute of Health and Medical Research (INSERM) U1048ToulouseCedex 4France
- University of Toulouse, UPS, Institute of Metabolic and Cardiovascular DiseasesToulouseFrance
| | - Andrei Timotin
- National Institute of Health and Medical Research (INSERM) U1048ToulouseCedex 4France
- University of Toulouse, UPS, Institute of Metabolic and Cardiovascular DiseasesToulouseFrance
| | - Jessica Roumegoux
- National Institute of Health and Medical Research (INSERM) U1048ToulouseCedex 4France
- University of Toulouse, UPS, Institute of Metabolic and Cardiovascular DiseasesToulouseFrance
| | - Chiara Alfarano
- National Institute of Health and Medical Research (INSERM) U1048ToulouseCedex 4France
- University of Toulouse, UPS, Institute of Metabolic and Cardiovascular DiseasesToulouseFrance
| | - Denis Calise
- University of Toulouse, UPS, Institute of Metabolic and Cardiovascular DiseasesToulouseFrance
- US006, Microsurgery ServicesToulouseCedex 4France
| | - Rodica Anesia
- National Institute of Health and Medical Research (INSERM) U1048ToulouseCedex 4France
- University of Toulouse, UPS, Institute of Metabolic and Cardiovascular DiseasesToulouseFrance
| | - Angelo Parini
- National Institute of Health and Medical Research (INSERM) U1048ToulouseCedex 4France
- University of Toulouse, UPS, Institute of Metabolic and Cardiovascular DiseasesToulouseFrance
| | - Philippe Valet
- National Institute of Health and Medical Research (INSERM) U1048ToulouseCedex 4France
- University of Toulouse, UPS, Institute of Metabolic and Cardiovascular DiseasesToulouseFrance
| | - Helene Tronchere
- National Institute of Health and Medical Research (INSERM) U1048ToulouseCedex 4France
- University of Toulouse, UPS, Institute of Metabolic and Cardiovascular DiseasesToulouseFrance
| | - Oksana Kunduzova
- National Institute of Health and Medical Research (INSERM) U1048ToulouseCedex 4France
- University of Toulouse, UPS, Institute of Metabolic and Cardiovascular DiseasesToulouseFrance
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Zhang X, Damacharla D, Ma D, Qi Y, Tagett R, Draghici S, Kowluru A, Yi Z. Quantitative proteomics reveals novel protein interaction partners of PP2A catalytic subunit in pancreatic β-cells. Mol Cell Endocrinol 2016; 424:1-11. [PMID: 26780722 PMCID: PMC4779412 DOI: 10.1016/j.mce.2016.01.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 12/15/2015] [Accepted: 01/07/2016] [Indexed: 12/19/2022]
Abstract
Protein phosphatase 2A (PP2A) is one of the major serine/threonine phosphatases. We hypothesize that PP2A regulates signaling cascades in pancreatic β-cells in the context of glucose-stimulated insulin secretion (GSIS). Using co-immunoprecipitation (co-IP) and tandem mass spectrometry, we globally identified the protein interaction partners of the PP2A catalytic subunit (PP2Ac) in insulin-secreting pancreatic β-cells. Among the 514 identified PP2Ac interaction partners, 476 were novel. This represents the first global view of PP2Ac protein-protein interactions caused by hyperglycemic conditions. Additionally, numerous PP2Ac partners were found involved in a variety of signaling pathways in the β-cell function, such as insulin secretion. Our data suggest that PP2A interacts with various signaling proteins necessary for physiological insulin secretion as well as signaling proteins known to regulate cell dysfunction and apoptosis in the pancreatic β-cells.
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Affiliation(s)
- Xiangmin Zhang
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI, 48201, USA
| | - Divyasri Damacharla
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI, 48201, USA
| | - Danjun Ma
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI, 48201, USA
| | - Yue Qi
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI, 48201, USA
| | - Rebecca Tagett
- Department of Computer Science, College of Engineering, Wayne State University, Detroit, MI, USA
| | - Sorin Draghici
- Department of Computer Science, College of Engineering, Wayne State University, Detroit, MI, USA
| | - Anjaneyulu Kowluru
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI, 48201, USA; β-Cell Biochemistry Laboratory, John D. Dingell VA Medical Center, Detroit, MI, 48201, USA
| | - Zhengping Yi
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI, 48201, USA.
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Theurey P, Tubbs E, Vial G, Jacquemetton J, Bendridi N, Chauvin MA, Alam MR, Le Romancer M, Vidal H, Rieusset J. Mitochondria-associated endoplasmic reticulum membranes allow adaptation of mitochondrial metabolism to glucose availability in the liver. J Mol Cell Biol 2016; 8:129-43. [DOI: 10.1093/jmcb/mjw004] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 11/01/2015] [Indexed: 12/20/2022] Open
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Lajarín-Cuesta R, Arribas RL, De Los Ríos C. Ligands for Ser/Thr phosphoprotein phosphatases: a patent review (2005-2015). Expert Opin Ther Pat 2016; 26:389-407. [DOI: 10.1517/13543776.2016.1135903] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Liu J, Wang H, Wang B, Chen T, Wang X, Huang P, Xu L, Guo Z. Microcystin-LR promotes proliferation by activating Akt/S6K1 pathway and disordering apoptosis and cell cycle associated proteins phosphorylation in HL7702 cells. Toxicol Lett 2016; 240:214-25. [DOI: 10.1016/j.toxlet.2015.10.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 09/30/2015] [Accepted: 10/17/2015] [Indexed: 12/14/2022]
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Apelin regulates FoxO3 translocation to mediate cardioprotective responses to myocardial injury and obesity. Sci Rep 2015; 5:16104. [PMID: 26542760 PMCID: PMC4635427 DOI: 10.1038/srep16104] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 09/25/2015] [Indexed: 12/22/2022] Open
Abstract
The increasing incidence of obesity accentuates the importance of identifying mechanisms and optimal therapeutic strategies for patients with heart failure (HF) in relation to obesity status. Here, we investigated the association between plasma level of apelin, an adipocyte-derived factor, and clinicopathological features of obese and non-obese patients with HF. We further explored potential regulatory mechanisms of cardiac cell fate responses in conditions combining myocardial injury and obesity. In a prospective, cross-sectional study involving patients with HF we show that obese patients (BMI ≥ 30 kg/m(2)) have higher left ventricular ejection fraction (LVEF) and greater levels of plasma apelin (p < 0.005) than non-obese patients (< 30 kg/m(2)), independently of ischemic etiology. In a mouse model combining ischemia-reperfusion (I/R) injury and high-fat diet (HFD)-induced obesity, we identify apelin as a novel regulator of FoxO3 trafficking in cardiomyocytes. Confocal microscopy analysis of cardiac cells revealed that apelin prevents nuclear translocation of FoxO3 in response to oxygen deprivation through a PI3K pathway. These findings uncover apelin as a novel regulator of FoxO3 nucleocytoplasmic trafficking in cardiac cells in response to stress and provide insight into its potential clinical relevance in obese patients with HF.
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Bharath LP, Ruan T, Li Y, Ravindran A, Wan X, Nhan JK, Walker ML, Deeter L, Goodrich R, Johnson E, Munday D, Mueller R, Kunz D, Jones D, Reese V, Summers SA, Babu PVA, Holland WL, Zhang QJ, Abel ED, Symons JD. Ceramide-Initiated Protein Phosphatase 2A Activation Contributes to Arterial Dysfunction In Vivo. Diabetes 2015; 64:3914-26. [PMID: 26253611 PMCID: PMC4613970 DOI: 10.2337/db15-0244] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2015] [Accepted: 07/17/2015] [Indexed: 12/18/2022]
Abstract
Prior studies have implicated accumulation of ceramide in blood vessels as a basis for vascular dysfunction in diet-induced obesity via a mechanism involving type 2 protein phosphatase (PP2A) dephosphorylation of endothelial nitric oxide synthase (eNOS). The current study sought to elucidate the mechanisms linking ceramide accumulation with PP2A activation and determine whether pharmacological inhibition of PP2A in vivo normalizes obesity-associated vascular dysfunction and limits the severity of hypertension. We show in endothelial cells that ceramide associates with the inhibitor 2 of PP2A (I2PP2A) in the cytosol, which disrupts the association of I2PP2A with PP2A leading to its translocation to the plasma membrane. The increased association between PP2A and eNOS at the plasma membrane promotes dissociation of an Akt-Hsp90-eNOS complex that is required for eNOS phosphorylation and activation. A novel small-molecule inhibitor of PP2A attenuated PP2A activation, prevented disruption of the Akt-Hsp90-eNOS complex in the vasculature, preserved arterial function, and maintained normal blood pressure in obese mice. These findings reveal a novel mechanism whereby ceramide initiates PP2A colocalization with eNOS and demonstrate that PP2A activation precipitates vascular dysfunction in diet-induced obesity. Therapeutic strategies targeted to reducing PP2A activation might be beneficial in attenuating vascular complications that exist in the context of type 2 diabetes, obesity, and conditions associated with insulin resistance.
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Affiliation(s)
- Leena P Bharath
- College of Health, The University of Utah, Salt Lake City, UT Division of Endocrinology, Metabolism and Diabetes, The University of Utah School of Medicine, Salt Lake City, UT Molecular Medicine Program, The University of Utah School of Medicine, Salt Lake City, UT
| | - Ting Ruan
- College of Health, The University of Utah, Salt Lake City, UT Division of Endocrinology, Metabolism and Diabetes, The University of Utah School of Medicine, Salt Lake City, UT
| | - Youyou Li
- College of Health, The University of Utah, Salt Lake City, UT Division of Endocrinology, Metabolism and Diabetes, The University of Utah School of Medicine, Salt Lake City, UT
| | - Anindita Ravindran
- College of Health, The University of Utah, Salt Lake City, UT Division of Endocrinology, Metabolism and Diabetes, The University of Utah School of Medicine, Salt Lake City, UT
| | - Xin Wan
- College of Health, The University of Utah, Salt Lake City, UT Division of Endocrinology, Metabolism and Diabetes, The University of Utah School of Medicine, Salt Lake City, UT
| | - Jennifer Kim Nhan
- College of Health, The University of Utah, Salt Lake City, UT Division of Endocrinology, Metabolism and Diabetes, The University of Utah School of Medicine, Salt Lake City, UT
| | - Matthew Lewis Walker
- College of Health, The University of Utah, Salt Lake City, UT Division of Endocrinology, Metabolism and Diabetes, The University of Utah School of Medicine, Salt Lake City, UT
| | - Lance Deeter
- College of Health, The University of Utah, Salt Lake City, UT Division of Endocrinology, Metabolism and Diabetes, The University of Utah School of Medicine, Salt Lake City, UT
| | - Rebekah Goodrich
- College of Health, The University of Utah, Salt Lake City, UT Division of Endocrinology, Metabolism and Diabetes, The University of Utah School of Medicine, Salt Lake City, UT
| | - Elizabeth Johnson
- College of Health, The University of Utah, Salt Lake City, UT Division of Endocrinology, Metabolism and Diabetes, The University of Utah School of Medicine, Salt Lake City, UT
| | - Derek Munday
- College of Health, The University of Utah, Salt Lake City, UT Division of Endocrinology, Metabolism and Diabetes, The University of Utah School of Medicine, Salt Lake City, UT
| | - Robert Mueller
- College of Health, The University of Utah, Salt Lake City, UT Division of Endocrinology, Metabolism and Diabetes, The University of Utah School of Medicine, Salt Lake City, UT
| | - David Kunz
- College of Health, The University of Utah, Salt Lake City, UT Division of Endocrinology, Metabolism and Diabetes, The University of Utah School of Medicine, Salt Lake City, UT
| | - Deborah Jones
- Division of Endocrinology, Metabolism and Diabetes, The University of Utah School of Medicine, Salt Lake City, UT
| | - Van Reese
- The University of Utah Geriatric Research, Education, and Clinical Center, George E. Wahlen VA Medical Center, Salt Lake City, UT
| | - Scott A Summers
- Baker IDI Heart and Diabetes Institute, Melbourne, Australia
| | | | - William L Holland
- Touchstone Diabetes Center, The University of Texas Southwestern Medical Center, Dallas, TX
| | - Quan-Jiang Zhang
- Fraternal Order of Eagles Diabetes Research Center and Division of Endocrinology and Metabolism, Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, IA
| | - E Dale Abel
- Fraternal Order of Eagles Diabetes Research Center and Division of Endocrinology and Metabolism, Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, IA
| | - J David Symons
- College of Health, The University of Utah, Salt Lake City, UT Division of Endocrinology, Metabolism and Diabetes, The University of Utah School of Medicine, Salt Lake City, UT Molecular Medicine Program, The University of Utah School of Medicine, Salt Lake City, UT
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Coughlan KA, Balon TW, Valentine RJ, Petrocelli R, Schultz V, Brandon A, Cooney GJ, Kraegen EW, Ruderman NB, Saha AK. Nutrient Excess and AMPK Downregulation in Incubated Skeletal Muscle and Muscle of Glucose Infused Rats. PLoS One 2015; 10:e0127388. [PMID: 25996822 PMCID: PMC4440828 DOI: 10.1371/journal.pone.0127388] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 04/15/2015] [Indexed: 11/18/2022] Open
Abstract
We have previously shown that incubation for 1h with excess glucose or leucine causes insulin resistance in rat extensor digitorum longus (EDL) muscle by inhibiting AMP-activated protein kinase (AMPK). To examine the events that precede and follow these changes, studies were performed in rat EDL incubated with elevated levels of glucose or leucine for 30min-2h. Incubation in high glucose (25mM) or leucine (100μM) significantly diminished AMPK activity by 50% within 30min, with further decreases occurring at 1 and 2h. The initial decrease in activity at 30min coincided with a significant increase in muscle glycogen. The subsequent decreases at 1h were accompanied by phosphorylation of αAMPK at Ser485/491, and at 2h by decreased SIRT1 expression and increased PP2A activity, all of which have previously been shown to diminish AMPK activity. Glucose infusion in vivo, which caused several fold increases in plasma glucose and insulin, produced similar changes but with different timing. Thus, the initial decrease in AMPK activity observed at 3h was associated with changes in Ser485/491 phosphorylation and SIRT1 expression and increased PP2A activity was a later event. These findings suggest that both ex vivo and in vivo, multiple factors contribute to fuel-induced decreases in AMPK activity in skeletal muscle and the insulin resistance that accompanies it.
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Affiliation(s)
- Kimberly A. Coughlan
- Department of Medicine, Section of Endocrinology and Diabetes, Boston University Medical Center, Boston, Massachusetts, United States of America
| | - Thomas W. Balon
- Department of Medicine, Section of Endocrinology and Diabetes, Boston University Medical Center, Boston, Massachusetts, United States of America
| | - Rudy J. Valentine
- Department of Medicine, Section of Endocrinology and Diabetes, Boston University Medical Center, Boston, Massachusetts, United States of America
| | - Robert Petrocelli
- Department of Medicine, Section of Endocrinology and Diabetes, Boston University Medical Center, Boston, Massachusetts, United States of America
| | - Vera Schultz
- Department of Medicine, Section of Endocrinology and Diabetes, Boston University Medical Center, Boston, Massachusetts, United States of America
| | - Amanda Brandon
- Diabetes and Obesity Program, Garvan Institute of Medical Research and School of Medical Sciences, University of NSW, Sydney, Australia
| | - Gregory J. Cooney
- Diabetes and Obesity Program, Garvan Institute of Medical Research and School of Medical Sciences, University of NSW, Sydney, Australia
| | - Edward W. Kraegen
- Diabetes and Obesity Program, Garvan Institute of Medical Research and School of Medical Sciences, University of NSW, Sydney, Australia
| | - Neil B. Ruderman
- Department of Medicine, Section of Endocrinology and Diabetes, Boston University Medical Center, Boston, Massachusetts, United States of America
| | - Asish K. Saha
- Department of Medicine, Section of Endocrinology and Diabetes, Boston University Medical Center, Boston, Massachusetts, United States of America
- * E-mail:
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Kumar S, Tikoo K. Independent role of PP2A and mTORc1 in palmitate induced podocyte death. Biochimie 2015; 112:73-84. [DOI: 10.1016/j.biochi.2015.02.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 02/13/2015] [Indexed: 11/26/2022]
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Haesen D, Sents W, Lemaire K, Hoorne Y, Janssens V. The Basic Biology of PP2A in Hematologic Cells and Malignancies. Front Oncol 2014; 4:347. [PMID: 25566494 PMCID: PMC4263090 DOI: 10.3389/fonc.2014.00347] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 11/20/2014] [Indexed: 12/30/2022] Open
Abstract
Reversible protein phosphorylation plays a crucial role in regulating cell signaling. In normal cells, phosphoregulation is tightly controlled by a network of protein kinases counterbalanced by several protein phosphatases. Deregulation of this delicate balance is widely recognized as a central mechanism by which cells escape external and internal self-limiting signals, eventually resulting in malignant transformation. A large fraction of hematologic malignancies is characterized by constitutive or unrestrained activation of oncogenic kinases. This is in part achieved by activating mutations, chromosomal rearrangements, or constitutive activation of upstream kinase regulators, in part by inactivation of their anti-oncogenic phosphatase counterparts. Protein phosphatase 2A (PP2A) represents a large family of cellular serine/threonine phosphatases with suspected tumor suppressive functions. In this review, we highlight our current knowledge about the complex structure and biology of these phosphatases in hematologic cells, thereby providing the rationale behind their diverse signaling functions. Eventually, this basic knowledge is a key to truly understand the tumor suppressive role of PP2A in leukemogenesis and to allow further rational development of therapeutic strategies targeting PP2A.
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Affiliation(s)
- Dorien Haesen
- Laboratory of Protein Phosphorylation and Proteomics, Department Cellular and Molecular Medicine, University of Leuven , Leuven , Belgium
| | - Ward Sents
- Laboratory of Protein Phosphorylation and Proteomics, Department Cellular and Molecular Medicine, University of Leuven , Leuven , Belgium
| | - Katleen Lemaire
- Gene Expression Unit, Department Cellular and Molecular Medicine, University of Leuven , Leuven , Belgium
| | - Yana Hoorne
- Laboratory of Protein Phosphorylation and Proteomics, Department Cellular and Molecular Medicine, University of Leuven , Leuven , Belgium
| | - Veerle Janssens
- Laboratory of Protein Phosphorylation and Proteomics, Department Cellular and Molecular Medicine, University of Leuven , Leuven , Belgium
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Xie X, Xu XM, Li N, Zhang YH, Zhao Y, Ma CY, Dong DL. DMH1 increases glucose metabolism through activating Akt in L6 rat skeletal muscle cells. PLoS One 2014; 9:e107776. [PMID: 25247550 PMCID: PMC4172596 DOI: 10.1371/journal.pone.0107776] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2014] [Accepted: 08/21/2014] [Indexed: 11/19/2022] Open
Abstract
DMH1(4-[6-(4-Isopropoxyphenyl)pyrazolo [1,5-a]pyrimidin-3-yl] quinoline) is a compound C analogue with the structural modifications at the 3- and 6-positions in pyrazolo[1,5-a]pyrimidine backbone. Compound C was reported to inhibit both AMPK and Akt. Our preliminary work found that DMH1 activated Akt. Since Akt was involved in glucose metabolism, we aimed to identify the effects of DMH1 on glucose metabolism in L6 rat muscle cells and the potential mechanism. Results showed that DMH1 increased lactic acid release and glucose consumption in L6 rat muscle cells in a dose-dependent manner. DMH1 activated Akt in L6 cells. Akt inhibitor inhibited DMH1-induced Akt activation and DMH1-induced increases of glucose uptake and consumption. DMH1 had no cytotoxicity in L6 cells, but inhibited mitochondrial function and reduced ATP production. DMH1 showed no effect on AMPK, but in the presence of Akt inhibitor, DMH1 significantly activated AMPK. Compound C inhibited DMH1-induced Akt activation in L6 cells. Compound C inhibited DMH1-induced increase of glucose uptake, consumption and lactic acid release in L6 cells. DMH1 inhibited PP2A activity, and PP2A activator forskolin reversed DMH1-induced Akt activation. We concluded that DMH1 increased glucose metabolism through activating Akt and DMH1 activated Akt through inhibiting PP2A activity in L6 rat muscle cells. In view of the analogue structure of DMH1 and compound C and the contrasting effects of DMH1 and compound C on Akt, the present study provides a novel leading chemical structure targeting Akt with potential use for regulating glucose metabolism.
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Affiliation(s)
- Xin Xie
- Department of Pharmacology (the State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), Harbin Medical University, Harbin, P.R. China
| | - Xiao-Ming Xu
- Department of Pharmacology (the State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), Harbin Medical University, Harbin, P.R. China
| | - Na Li
- Department of Pharmacology (the State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), Harbin Medical University, Harbin, P.R. China
| | - Yong-Hui Zhang
- Department of Pharmacology (the State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), Harbin Medical University, Harbin, P.R. China
| | - Yu Zhao
- Department of Pharmacology (the State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), Harbin Medical University, Harbin, P.R. China
| | - Chun-Yan Ma
- Department of Pharmacology (the State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), Harbin Medical University, Harbin, P.R. China
| | - De-Li Dong
- Department of Pharmacology (the State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), Harbin Medical University, Harbin, P.R. China
- * E-mail:
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48
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Galbo T, Perry RJ, Nishimura E, Samuel VT, Quistorff B, Shulman GI. PP2A inhibition results in hepatic insulin resistance despite Akt2 activation. Aging (Albany NY) 2014; 5:770-81. [PMID: 24150286 PMCID: PMC3838779 DOI: 10.18632/aging.100611] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In the liver, insulin suppresses hepatic gluconeogenesis by activating Akt, which inactivates the key gluconeogenic transcription factor FoxO1 (Forkhead Box O1). Recent studies have implicated hyperactivity of the Akt phosphatase Protein Phosphatase 2A (PP2A) and impaired Akt signaling as a molecular defect underlying insulin resistance. We therefore hypothesized that PP2A inhibition would enhance insulin-stimulated Akt activity and decrease glucose production. PP2A inhibitors increased hepatic Akt phosphorylation and inhibited FoxO1 in vitro and in vivo, and suppressed gluconeogenesis in hepatocytes. Paradoxically, PP2A inhibition exacerbated insulin resistance in vivo. This was explained by phosphorylation of both hepatic glycogen synthase (GS) (inactivation) and phosphorylase (activation) resulting in impairment of glycogen storage. Our findings underline the significance of GS and Phosphorylase as hepatic PP2A substrates and importance of glycogen metabolism in acute plasma glucose regulation.
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Affiliation(s)
- Thomas Galbo
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06510, USA
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49
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Abstract
The prevalence of diabetes is increasing rapidly worldwide. A cardinal feature of most forms of diabetes is the lack of insulin-producing capability, due to the loss of insulin-producing β-cells, impaired glucose-sensitive insulin secretion from the β-cell, or a combination thereof, the reasons for which largely remain elusive. Reversible phosphorylation is an important and versatile mechanism for regulating the biological activity of many intracellular proteins, which, in turn, controls a variety of cellular functions. For instance, significant changes in protein kinase activities and in protein phosphorylation patterns occur subsequent to the stimulation of insulin release by glucose. Therefore, the molecular mechanisms regulating the phosphorylation of proteins involved in the insulin secretory process by the β-cell have been extensively investigated. However, far less is known about the role and regulation of protein dephosphorylation by various protein phosphatases. Herein, we review extant data implicating serine/threonine and tyrosine phosphatases in various aspects of healthy and diabetic islet biology, ranging from control of hormonal stimulus-secretion coupling to mitogenesis and apoptosis.
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Affiliation(s)
- Henrik Ortsäter
- Biovation Park TelgeSödertälje, SwedenResearch UnitSödertälje Hospital, SE-152 86 Södertälje, SwedenDegenerative Disease ProgramSanford-Burnham Medical Research Institute, Del E. Webb Neuroscience, Aging and Stem Cell Research Center, 10901 North Torrey Pines Road, La Jolla, California 92037, USADepartment of Biochemistry and Molecular BiologyCollege of Medicine, University of South Alabama, Mobile, Alabama 36688, USADepartment of Internal MedicineSödertälje Hospital, Södertälje, SwedenBiovation Park TelgeSödertälje, SwedenResearch UnitSödertälje Hospital, SE-152 86 Södertälje, SwedenDegenerative Disease ProgramSanford-Burnham Medical Research Institute, Del E. Webb Neuroscience, Aging and Stem Cell Research Center, 10901 North Torrey Pines Road, La Jolla, California 92037, USADepartment of Biochemistry and Molecular BiologyCollege of Medicine, University of South Alabama, Mobile, Alabama 36688, USADepartment of Internal MedicineSödertälje Hospital, Södertälje, Sweden
| | - Nina Grankvist
- Biovation Park TelgeSödertälje, SwedenResearch UnitSödertälje Hospital, SE-152 86 Södertälje, SwedenDegenerative Disease ProgramSanford-Burnham Medical Research Institute, Del E. Webb Neuroscience, Aging and Stem Cell Research Center, 10901 North Torrey Pines Road, La Jolla, California 92037, USADepartment of Biochemistry and Molecular BiologyCollege of Medicine, University of South Alabama, Mobile, Alabama 36688, USADepartment of Internal MedicineSödertälje Hospital, Södertälje, Sweden
| | - Richard E Honkanen
- Biovation Park TelgeSödertälje, SwedenResearch UnitSödertälje Hospital, SE-152 86 Södertälje, SwedenDegenerative Disease ProgramSanford-Burnham Medical Research Institute, Del E. Webb Neuroscience, Aging and Stem Cell Research Center, 10901 North Torrey Pines Road, La Jolla, California 92037, USADepartment of Biochemistry and Molecular BiologyCollege of Medicine, University of South Alabama, Mobile, Alabama 36688, USADepartment of Internal MedicineSödertälje Hospital, Södertälje, Sweden
| | - Åke Sjöholm
- Biovation Park TelgeSödertälje, SwedenResearch UnitSödertälje Hospital, SE-152 86 Södertälje, SwedenDegenerative Disease ProgramSanford-Burnham Medical Research Institute, Del E. Webb Neuroscience, Aging and Stem Cell Research Center, 10901 North Torrey Pines Road, La Jolla, California 92037, USADepartment of Biochemistry and Molecular BiologyCollege of Medicine, University of South Alabama, Mobile, Alabama 36688, USADepartment of Internal MedicineSödertälje Hospital, Södertälje, SwedenBiovation Park TelgeSödertälje, SwedenResearch UnitSödertälje Hospital, SE-152 86 Södertälje, SwedenDegenerative Disease ProgramSanford-Burnham Medical Research Institute, Del E. Webb Neuroscience, Aging and Stem Cell Research Center, 10901 North Torrey Pines Road, La Jolla, California 92037, USADepartment of Biochemistry and Molecular BiologyCollege of Medicine, University of South Alabama, Mobile, Alabama 36688, USADepartment of Internal MedicineSödertälje Hospital, Södertälje, SwedenBiovation Park TelgeSödertälje, SwedenResearch UnitSödertälje Hospital, SE-152 86 Södertälje, SwedenDegenerative Disease ProgramSanford-Burnham Medical Research Institute, Del E. Webb Neuroscience, Aging and Stem Cell Research Center, 10901 North Torrey Pines Road, La Jolla, California 92037, USADepartment of Biochemistry and Molecular BiologyCollege of Medicine, University of South Alabama, Mobile, Alabama 36688, USADepartment of Internal MedicineSödertälje Hospital, Södertälje, Sweden
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50
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Caruso M, Ma D, Msallaty Z, Lewis M, Seyoum B, Al-janabi W, Diamond M, Abou-Samra AB, Højlund K, Tagett R, Draghici S, Zhang X, Horowitz JF, Yi Z. Increased interaction with insulin receptor substrate 1, a novel abnormality in insulin resistance and type 2 diabetes. Diabetes 2014; 63:1933-47. [PMID: 24584551 PMCID: PMC4030113 DOI: 10.2337/db13-1872] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Insulin receptor substrate 1 (IRS1) is a key mediator of insulin signal transduction. Perturbations involving IRS1 complexes may lead to the development of insulin resistance and type 2 diabetes (T2D). Surprisingly little is known about the proteins that interact with IRS1 in humans under health and disease conditions. We used a proteomic approach to assess IRS1 interaction partners in skeletal muscle from lean healthy control subjects (LCs), obese insulin-resistant nondiabetic control subjects (OCs), and participants with T2D before and after insulin infusion. We identified 113 novel endogenous IRS1 interaction partners, which represents the largest IRS1 interactome in humans and provides new targets for studies of IRS1 complexes in various diseases. Furthermore, we generated the first global picture of IRS1 interaction partners in LCs, and how they differ in OCs and T2D patients. Interestingly, dozens of proteins in OCs and/or T2D patients exhibited increased associations with IRS1 compared with LCs under the basal and/or insulin-stimulated conditions, revealing multiple new dysfunctional IRS1 pathways in OCs and T2D patients. This novel abnormality, increased interaction of multiple proteins with IRS1 in obesity and T2D in humans, provides new insights into the molecular mechanism of insulin resistance and identifies new targets for T2D drug development.
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Affiliation(s)
- Michael Caruso
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy/Health Sciences, Wayne State University, Detroit, MI
| | - Danjun Ma
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy/Health Sciences, Wayne State University, Detroit, MI
| | - Zaher Msallaty
- Division of Endocrinology, Wayne State University School of Medicine, Wayne State University, Detroit, MI
| | - Monique Lewis
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy/Health Sciences, Wayne State University, Detroit, MI
| | - Berhane Seyoum
- Division of Endocrinology, Wayne State University School of Medicine, Wayne State University, Detroit, MI
| | - Wissam Al-janabi
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy/Health Sciences, Wayne State University, Detroit, MI
| | - Michael Diamond
- Department of Obstetrics and Gynecology, Wayne State University, Detroit, MIDepartment of Obstetrics and Gynecology, Georgia Regents University, Augusta, GA
| | - Abdul B Abou-Samra
- Division of Endocrinology, Wayne State University School of Medicine, Wayne State University, Detroit, MIDepartment of Medicine, Hamad Medical Corporation, Doha, Qatar
| | - Kurt Højlund
- Diabetes Research Centre, Department of Endocrinology, Odense University Hospital, Odense, Denmark
| | - Rebecca Tagett
- Department of Computer Science, College of Engineering, Wayne State University, Detroit, MI
| | - Sorin Draghici
- Department of Computer Science, College of Engineering, Wayne State University, Detroit, MI
| | - Xiangmin Zhang
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy/Health Sciences, Wayne State University, Detroit, MI
| | | | - Zhengping Yi
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy/Health Sciences, Wayne State University, Detroit, MI
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