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Wątroba M, Grabowska AD, Szukiewicz D. Effects of Diabetes Mellitus-Related Dysglycemia on the Functions of Blood-Brain Barrier and the Risk of Dementia. Int J Mol Sci 2023; 24:10069. [PMID: 37373216 DOI: 10.3390/ijms241210069] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Revised: 06/11/2023] [Accepted: 06/12/2023] [Indexed: 06/29/2023] Open
Abstract
Diabetes mellitus is one of the most common metabolic diseases worldwide, and its long-term complications include neuropathy, referring both to the peripheral and to the central nervous system. Detrimental effects of dysglycemia, especially hyperglycemia, on the structure and function of the blood-brain barrier (BBB), seem to be a significant backgrounds of diabetic neuropathy pertaining to the central nervous system (CNS). Effects of hyperglycemia, including excessive glucose influx to insulin-independent cells, may induce oxidative stress and secondary innate immunity dependent inflammatory response, which can damage cells within the CNS, thus promoting neurodegeneration and dementia. Advanced glycation end products (AGE) may exert similar, pro-inflammatory effects through activating receptors for advanced glycation end products (RAGE), as well as some pattern-recognition receptors (PRR). Moreover, long-term hyperglycemia can promote brain insulin resistance, which may in turn promote Aβ aggregate accumulation and tau hyperphosphorylation. This review is focused on a detailed analysis of the effects mentioned above towards the CNS, with special regard to mechanisms taking part in the pathogenesis of central long-term complications of diabetes mellitus initiated by the loss of BBB integrity.
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Affiliation(s)
- Mateusz Wątroba
- Laboratory of the Blood-Brain Barrier, Department of Biophysics, Physiology & Pathophysiology, Medical University of Warsaw, Chałubinskiego 5, 02-004 Warsaw, Poland
| | - Anna D Grabowska
- Laboratory of the Blood-Brain Barrier, Department of Biophysics, Physiology & Pathophysiology, Medical University of Warsaw, Chałubinskiego 5, 02-004 Warsaw, Poland
| | - Dariusz Szukiewicz
- Laboratory of the Blood-Brain Barrier, Department of Biophysics, Physiology & Pathophysiology, Medical University of Warsaw, Chałubinskiego 5, 02-004 Warsaw, Poland
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2
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Kitamura H. Ubiquitin-Specific Proteases (USPs) and Metabolic Disorders. Int J Mol Sci 2023; 24:3219. [PMID: 36834633 PMCID: PMC9966627 DOI: 10.3390/ijms24043219] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 02/02/2023] [Accepted: 02/03/2023] [Indexed: 02/10/2023] Open
Abstract
Ubiquitination and deubiquitination are reversible processes that modify the characteristics of target proteins, including stability, intracellular localization, and enzymatic activity. Ubiquitin-specific proteases (USPs) constitute the largest deubiquitinating enzyme family. To date, accumulating evidence indicates that several USPs positively and negatively affect metabolic diseases. USP22 in pancreatic β-cells, USP2 in adipose tissue macrophages, USP9X, 20, and 33 in myocytes, USP4, 7, 10, and 18 in hepatocytes, and USP2 in hypothalamus improve hyperglycemia, whereas USP19 in adipocytes, USP21 in myocytes, and USP2, 14, and 20 in hepatocytes promote hyperglycemia. In contrast, USP1, 5, 9X, 14, 15, 22, 36, and 48 modulate the progression of diabetic nephropathy, neuropathy, and/or retinopathy. USP4, 10, and 18 in hepatocytes ameliorates non-alcoholic fatty liver disease (NAFLD), while hepatic USP2, 11, 14, 19, and 20 exacerbate it. The roles of USP7 and 22 in hepatic disorders are controversial. USP9X, 14, 17, and 20 in vascular cells are postulated to be determinants of atherosclerosis. Moreover, mutations in the Usp8 and Usp48 loci in pituitary tumors cause Cushing syndrome. This review summarizes the current knowledge about the modulatory roles of USPs in energy metabolic disorders.
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Affiliation(s)
- Hiroshi Kitamura
- Laboratory of Comparative Medicine, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu 069-8501, Japan
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3
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Kitamura H, Hashimoto M. USP2-Related Cellular Signaling and Consequent Pathophysiological Outcomes. Int J Mol Sci 2021; 22:1209. [PMID: 33530560 PMCID: PMC7865608 DOI: 10.3390/ijms22031209] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 01/22/2021] [Accepted: 01/23/2021] [Indexed: 12/13/2022] Open
Abstract
Ubiquitin specific protease (USP) 2 is a multifunctional deubiquitinating enzyme. USP2 modulates cell cycle progression, and therefore carcinogenesis, via the deubiquitination of cyclins and Aurora-A. Other tumorigenic molecules, including epidermal growth factor and fatty acid synthase, are also targets for USP2. USP2 additionally prevents p53 signaling. On the other hand, USP2 functions as a key component of the CLOCK/BMAL1 complex and participates in rhythmic gene expression in the suprachiasmatic nucleus and liver. USP2 variants influence energy metabolism by controlling hepatic gluconeogenesis, hepatic cholesterol uptake, adipose tissue inflammation, and subsequent systemic insulin sensitivity. USP2 also has the potential to promote surface expression of ion channels in renal and intestinal epithelial cells. In addition to modifying the production of cytokines in immune cells, USP2 also modulates the signaling molecules that are involved in cytokine signaling in the target cells. Usp2 knockout mice exhibit changes in locomotion and male fertility, which suggest roles for USP2 in the central nervous system and male genital tract, respectively. In this review, we summarize the cellular events with USP2 contributions and list the signaling molecules that are upstream or downstream of USP2. Additionally, we describe phenotypic differences found in the in vitro and in vivo experimental models.
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Affiliation(s)
- Hiroshi Kitamura
- Laboratory of Veterinary Physiology, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan;
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Xu L, Zhang P, Huang Z, Zhong L, Li H, Liu L, Liu J, Xiao H, Li Y. Hypoglycemia during Short-Term Intensive Insulin Therapy and Its Association with Long-Term Glycemic Remission in Patients with Newly Diagnosed Type 2 Diabetes. J Diabetes Res 2020; 2020:4097469. [PMID: 32149152 PMCID: PMC7049822 DOI: 10.1155/2020/4097469] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 01/26/2020] [Accepted: 02/01/2020] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Short-term intensive insulin therapy induces long-term glycemic remission in half of patients with newly diagnosed type 2 diabetes. The concomitant hypoglycemia needs further analysis. METHODS We collected data from three randomized trials conducted with the same inclusion and exclusion criteria at our institution from 2002 to 2015. Continuous subcutaneous insulin infusion (CSII) was provided to achieve the glycemic goals within a week and then maintained for 14 days. Hypoglycemia episodes during short-term treatment and the one-year drug-free glycemic remission were observed. RESULTS A total of 244 patients were included. The per day episode of mild hypoglycemia (3.0-3.9 mmol/L) was higher in the remission group than in the nonremission group (0.26 ± 0.20 vs. 0.18 ± 0.21, P = 0.005). However, a moderate hypoglycemia episode (<3.0 mmol/L) per day was insignificantly lower in the remission group (0.02 ± 0.04 vs. 0.03 ± 0.04, P = 0.005). However, a moderate hypoglycemia episode (<3.0 mmol/L) per day was insignificantly lower in the remission group (0.02 ± 0.04 vs. 0.03 ± 0.04, P = 0.005). However, a moderate hypoglycemia episode (<3.0 mmol/L) per day was insignificantly lower in the remission group (0.02 ± 0.04 vs. 0.03 ± 0.04, P = 0.005). However, a moderate hypoglycemia episode (<3.0 mmol/L) per day was insignificantly lower in the remission group (0.02 ± 0.04 vs. 0.03 ± 0.04. CONCLUSIONS Mild hypoglycemic episodes during the continuing insulin dose reduction period indicate a long-term drug-free euglycemic remission in patients with newly diagnosed type 2 diabetes. However, the insulin dosage should be reduced even more quickly in the future treatment to decrease the potential harms.
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Affiliation(s)
- Lijuan Xu
- Department of Endocrinology, The First Affiliated Hospital, Sun Yat-Sen University, 58th of Zhongshan Er Road, Guangzhou, China 510080
| | - Pengyuan Zhang
- Department of Endocrinology, The First Affiliated Hospital, Sun Yat-Sen University, 58th of Zhongshan Er Road, Guangzhou, China 510080
| | - Zhimin Huang
- Department of Endocrinology, The First Affiliated Hospital, Sun Yat-Sen University, 58th of Zhongshan Er Road, Guangzhou, China 510080
| | - Liangying Zhong
- Department of Laboratory Medicine, The First Affiliated Hospital, Sun Yat-Sen University, 58th of Zhongshan Er Road, Guangzhou, China 510080
| | - Hai Li
- Department of Endocrinology, The First Affiliated Hospital, Sun Yat-Sen University, 58th of Zhongshan Er Road, Guangzhou, China 510080
| | - Liehua Liu
- Department of Endocrinology, The First Affiliated Hospital, Sun Yat-Sen University, 58th of Zhongshan Er Road, Guangzhou, China 510080
| | - Juan Liu
- Department of Endocrinology, The First Affiliated Hospital, Sun Yat-Sen University, 58th of Zhongshan Er Road, Guangzhou, China 510080
| | - Haipeng Xiao
- Department of Endocrinology, The First Affiliated Hospital, Sun Yat-Sen University, 58th of Zhongshan Er Road, Guangzhou, China 510080
| | - Yanbing Li
- Department of Endocrinology, The First Affiliated Hospital, Sun Yat-Sen University, 58th of Zhongshan Er Road, Guangzhou, China 510080
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5
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Dewan N, Shukla V, Rehni AK, Koronowski KB, Klingbeil KD, Stradecki‐Cohan H, Garrett TJ, Rundek T, Perez‐Pinzon MA, Dave KR. Exposure to recurrent hypoglycemia alters hippocampal metabolism in treated streptozotocin-induced diabetic rats. CNS Neurosci Ther 2020; 26:126-135. [PMID: 31282100 PMCID: PMC6930817 DOI: 10.1111/cns.13186] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Revised: 05/31/2019] [Accepted: 06/04/2019] [Indexed: 12/13/2022] Open
Abstract
AIMS Exposure to recurrent hypoglycemia (RH) is common in diabetic patients receiving glucose-lowering therapies and is implicated in causing cognitive impairments. Despite the significant effect of RH on hippocampal function, the underlying mechanisms are currently unknown. Our goal was to determine the effect of RH exposure on hippocampal metabolism in treated streptozotocin-diabetic rats. METHODS Hyperglycemia was corrected by insulin pellet implantation. Insulin-treated diabetic (ITD) rats were exposed to mild/moderate RH once a day for 5 consecutive days. RESULTS The effect of RH on hippocampal metabolism revealed 65 significantly altered metabolites in the RH group compared with controls. Several significant differences in metabolite levels belonging to major pathways (eg, Krebs cycle, gluconeogenesis, and amino acid metabolism) were discovered in RH-exposed ITD rats when compared to a control group. Key glycolytic enzymes including hexokinase, phosphofructokinase, and pyruvate kinase were affected by RH exposure. CONCLUSION Our results demonstrate that the exposure to RH leads to metabolomics alterations in the hippocampus of insulin-treated streptozotocin-diabetic rats. Understanding how RH affects hippocampal metabolism may help attenuate the adverse effects of RH on hippocampal functions.
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Affiliation(s)
- Neelesh Dewan
- Peritz Scheinberg Cerebral Vascular Disease Research LaboratoriesUniversity of Miami School of MedicineMiamiFloridaUSA
- Department of NeurologyUniversity of Miami School of MedicineMiamiFloridaUSA
| | - Vibha Shukla
- Peritz Scheinberg Cerebral Vascular Disease Research LaboratoriesUniversity of Miami School of MedicineMiamiFloridaUSA
- Department of NeurologyUniversity of Miami School of MedicineMiamiFloridaUSA
| | - Ashish K. Rehni
- Peritz Scheinberg Cerebral Vascular Disease Research LaboratoriesUniversity of Miami School of MedicineMiamiFloridaUSA
- Department of NeurologyUniversity of Miami School of MedicineMiamiFloridaUSA
| | - Kevin B. Koronowski
- Peritz Scheinberg Cerebral Vascular Disease Research LaboratoriesUniversity of Miami School of MedicineMiamiFloridaUSA
- Department of NeurologyUniversity of Miami School of MedicineMiamiFloridaUSA
- Neuroscience ProgramUniversity of Miami School of MedicineMiamiFloridaUSA
| | - Kyle D. Klingbeil
- Peritz Scheinberg Cerebral Vascular Disease Research LaboratoriesUniversity of Miami School of MedicineMiamiFloridaUSA
- Department of NeurologyUniversity of Miami School of MedicineMiamiFloridaUSA
| | - Holly Stradecki‐Cohan
- Peritz Scheinberg Cerebral Vascular Disease Research LaboratoriesUniversity of Miami School of MedicineMiamiFloridaUSA
- Department of NeurologyUniversity of Miami School of MedicineMiamiFloridaUSA
- Neuroscience ProgramUniversity of Miami School of MedicineMiamiFloridaUSA
| | - Timothy J. Garrett
- Southeast Center for Integrated Metabolomics, Clinical and Translational Science InstituteUniversity of FloridaGainesvilleFloridaUSA
| | - Tatjana Rundek
- Department of NeurologyUniversity of Miami School of MedicineMiamiFloridaUSA
- Evelyn F. McKnight Brain InstituteUniversity of Miami School of MedicineMiamiFloridaUSA
| | - Miguel A. Perez‐Pinzon
- Peritz Scheinberg Cerebral Vascular Disease Research LaboratoriesUniversity of Miami School of MedicineMiamiFloridaUSA
- Department of NeurologyUniversity of Miami School of MedicineMiamiFloridaUSA
- Neuroscience ProgramUniversity of Miami School of MedicineMiamiFloridaUSA
- Evelyn F. McKnight Brain InstituteUniversity of Miami School of MedicineMiamiFloridaUSA
| | - Kunjan R. Dave
- Peritz Scheinberg Cerebral Vascular Disease Research LaboratoriesUniversity of Miami School of MedicineMiamiFloridaUSA
- Department of NeurologyUniversity of Miami School of MedicineMiamiFloridaUSA
- Neuroscience ProgramUniversity of Miami School of MedicineMiamiFloridaUSA
- Evelyn F. McKnight Brain InstituteUniversity of Miami School of MedicineMiamiFloridaUSA
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Agrawal R, Durupt G, Verma D, Montgomery M, Vieira-de Abreu A, Taylor C, Swaminathan S, Fisher SJ. MicroRNA-7a overexpression in VMH restores the sympathoadrenal response to hypoglycemia. JCI Insight 2019; 4:130521. [PMID: 31619588 PMCID: PMC6824313 DOI: 10.1172/jci.insight.130521] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 08/31/2019] [Indexed: 12/19/2022] Open
Abstract
It is proposed that the impaired sympathoadrenal response to hypoglycemia induced by recurrent insulin-induced hypoglycemia (RH) is an adaptive phenomenon induced by specific changes in microRNA expression in the ventromedial hypothalamus (VMH). To test this hypothesis, genome-wide microRNAomic profiling of the VMH by RNA-sequencing was performed in control rats and rats treated for RH. Differential expression analysis identified microRNA-7a-5p and microRNA-665 as potential mediators of this phenomenon. To further test this hypothesis, experiments were conducted consisting of targeted lentiviral-mediated overexpression of microRNA-7a-5p and downregulation of microRNA-665 in the VMH. Hyperinsulinemic hypoglycemic clamp experiments demonstrated that targeted overexpression of microRNA-7a-5p (but not downregulation of microRNA-665) in the VMH of RH rats restored the epinephrine response to hypoglycemia. This restored response to hypoglycemia was associated with a restoration of GABAA receptor gene expression. Finally, a direct interaction of microRNA-7a-5p with the 3'-UTR of GABAA receptor α1-subunit (Gabra1) gene was demonstrated in a luciferase assay. These findings indicate that (a) the impaired sympathoadrenal response RH induces is associated with changes in VMH microRNA expression and (b) microRNA-7a-5p, possibly via direct downregulation of GABA receptor gene expression, may serve as a mediator of the altered sympathoadrenal response to hypoglycemia.
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Affiliation(s)
- Rahul Agrawal
- Division of Endocrinology, Metabolism, and Diabetes, Department of Internal Medicine, and
| | - Griffin Durupt
- Division of Endocrinology, Metabolism, and Diabetes, Department of Internal Medicine, and
| | - Dinesh Verma
- Division of Infectious Diseases, Department of Internal Medicine, and
| | - Michael Montgomery
- Division of Endocrinology, Metabolism, and Diabetes, Department of Internal Medicine, and
| | | | - Casey Taylor
- Division of Endocrinology, Metabolism, and Diabetes, Department of Internal Medicine, and
| | | | - Simon J. Fisher
- Division of Endocrinology, Metabolism, and Diabetes, Department of Internal Medicine, and
- Department of Biochemistry, School of Medicine, University of Utah, Salt Lake City, USA
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Capulli M, Ponzetti M, Maurizi A, Gemini-Piperni S, Berger T, Mak TW, Teti A, Rucci N. A Complex Role for Lipocalin 2 in Bone Metabolism: Global Ablation in Mice Induces Osteopenia Caused by an Altered Energy Metabolism. J Bone Miner Res 2018; 33:1141-1153. [PMID: 29444358 DOI: 10.1002/jbmr.3406] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 01/29/2018] [Accepted: 02/08/2018] [Indexed: 12/16/2022]
Abstract
Lipocalin 2 (Lcn2) is an adipokine that carries out a variety of functions in diverse organs. We investigated the bone phenotype and the energy metabolism of Lcn2 globally deleted mice (Lcn2-/- ) at different ages. Lcn2-/- mice were largely osteopenic, exhibiting lower trabecular bone volume, lesser trabecular number, and higher trabecular separation when compared to wild-type (WT) mice. Lcn2-/- mice showed a lower osteoblast number and surface over bone surface, and subsequently a significantly lower bone formation rate, while osteoclast variables were unremarkable. Surprisingly, we found no difference in alkaline phosphatase (ALP) activity or in nodule mineralization in Lcn2-/- calvaria osteoblast cultures, while less ALP-positive colonies were obtained from freshly isolated Lcn2-/- bone marrow stromal cells, suggesting a nonautonomous osteoblast response to Lcn2 ablation. Given that Lcn2-/- mice showed higher body weight and hyperphagia, we investigated whether their osteoblast impairment could be due to altered energy metabolism. Lcn2-/- mice showed lower fasted glycemia and hyperinsulinemia. Consistently, glucose tolerance was significantly higher in Lcn2-/- compared to WT mice, while insulin tolerance was similar. Lcn2-/- mice also exhibited polyuria, glycosuria, proteinuria, and renal cortex vacuolization, suggesting a kidney contribution to their phenotype. Interestingly, the expression of the glucose transporter protein type 1, that conveys glucose into the osteoblasts and is essential for osteogenesis, was significantly lower in the Lcn2-/- bone, possibly explaining the in vivo osteoblast impairment induced by the global Lcn2 ablation. Taken together, these results unveil an important role of Lcn2 in bone metabolism, highlighting a link with glucose metabolism that is more complex than expected from the current knowledge. © 2018 American Society for Bone and Mineral Research.
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Affiliation(s)
- Mattia Capulli
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
| | - Marco Ponzetti
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
| | - Antonio Maurizi
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
| | - Sara Gemini-Piperni
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
| | - Thorsten Berger
- The Campbell Family Institute for Breast Cancer Research, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Tak Wah Mak
- The Campbell Family Institute for Breast Cancer Research, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Anna Teti
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
| | - Nadia Rucci
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
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8
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Jarrar YB, Al-Essa L, Kilani A, Hasan M, Al-Qerem W. Alterations in the gene expression of drug and arachidonic acid-metabolizing Cyp450 in the livers of controlled and uncontrolled insulin-dependent diabetic mice. Diabetes Metab Syndr Obes 2018; 11:483-492. [PMID: 30288071 PMCID: PMC6162993 DOI: 10.2147/dmso.s172664] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Diabetic patients have lower capacity to metabolize drugs in comparison to normal people. Therefore, the present study aimed to investigate the alterations in gene expression of drug and arachidonic acid metabolizing cytochrome p450s (cyp450s) in the livers of controlled (CDM) and uncontrolled (UDM) insulin-dependent diabetic mice. METHODS Balb/c mice were treated with single dose of streptozocin (240 mg/kg) to induce diabetes and compared with control group, which was treated with citric buffer (pH =4.5). After 3 days, the blood glucose level was measured to confirm the induction of diabetes. Normalization of blood glucose level in diabetic mice was achieved after 0.1 mL/kg Mixtard® insulin therapy for more 5 days. Then, the mice livers were isolated to extract RNA and convert it to cDNA. The gene expression of 14 genes, which play a major role in drug and arachidonic acid metabolism, were measured using quantitative real-time polymerase chain reaction technique. RESULTS It was found that the gene expression was downregulated (ANOVA test, P-value <0.05) in the livers of UDM mice. The most downregulated genes were cyp4a12, cyp1a2, and slc22a1 with more than 10-fold reduction. The livers of CDM mice showed significantly (P-value <0.05) higher levels of mRNA than UDM mice, but still lower than the non-diabetic mice. CONCLUSION This study concluded that hepatic gene expression of drug metabolizing and arachidonic acid- cyp450 enzymes is reduced in insulin-dependent diabetic mice, which can explain, at least in part, the variation in drug and fatty acid metabolism between normal and diabetic patients.
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Affiliation(s)
- Yazun Bashir Jarrar
- Department of Pharmacy, College of Pharmacy, Al-Zaytoonah University of Jordan, Airport street, Amman, Jordan,
| | - Luay Al-Essa
- Department of Pharmacy, College of Pharmacy, Al-Zaytoonah University of Jordan, Airport street, Amman, Jordan,
| | - Abdulhasib Kilani
- Department of Pharmacy, College of Pharmacy, Al-Zaytoonah University of Jordan, Airport street, Amman, Jordan,
| | - Mariam Hasan
- Department of Pharmacy, College of Pharmacy, Al-Zaytoonah University of Jordan, Airport street, Amman, Jordan,
| | - Walid Al-Qerem
- Department of Pharmacy, College of Pharmacy, Al-Zaytoonah University of Jordan, Airport street, Amman, Jordan,
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9
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Saito N, Kimura S, Miyamoto T, Fukushima S, Amagasa M, Shimamoto Y, Nishioka C, Okamoto S, Toda C, Washio K, Asano A, Miyoshi I, Takahashi E, Kitamura H. Macrophage ubiquitin-specific protease 2 modifies insulin sensitivity in obese mice. Biochem Biophys Rep 2017; 9:322-329. [PMID: 28956020 PMCID: PMC5614627 DOI: 10.1016/j.bbrep.2017.01.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 12/24/2016] [Accepted: 01/23/2017] [Indexed: 12/17/2022] Open
Abstract
We previously reported that ubiquitin-specific protease (USP) 2 in macrophages down-regulates genes associated with metabolic diseases, suggesting a putative anti-diabetic role for USP2 in macrophages. In this study, we evaluate this role at both cellular and individual levels. Isolated macrophages forcibly expressing Usp2a, a longer splicing variant of USP2, failed to modulate the insulin sensitivity of 3T3-L1 adipocytes. Similarly, macrophage-selective overexpression of Usp2a in mice (Usp2a transgenic mice) had a negligible effect on insulin sensitivity relative to wild type littermates following a three-month high-fat diet. However, Usp2a transgenic mice exhibited fewer M1 macrophages in their mesenteric adipose tissue. Following a six-month high-fat diet, Usp2a transgenic mice exhibited a retarded progression of insulin resistance in their skeletal muscle and liver, and an improvement in insulin sensitivity at an individual level. Although conditioned media from Usp2a-overexpressing macrophages did not directly affect the insulin sensitivity of C2C12 myotubes compared to media from control macrophages, they did increase the insulin sensitivity of C2C12 cells after subsequent conditioning with 3T3-L1 cells. These results indicate that macrophage USP2A hampers obesity-elicited insulin resistance via an adipocyte-dependent mechanism. USP2A controls macrophage population in mesenteric adipose tissue during obesity. Overexpression of USP2A in macrophages retards progression of insulin resistance. Overexpression of USP2A in macrophages represses high-fat diet-induced obesity. Macrophage USP2A controls insulin sensitivity of muscle dependent on adipocytes.
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Key Words
- DMEM, Dulbecco's modified Eagle medium
- Diabetes
- ELISA, enzyme-linked immunosorbent assay
- GAPDH, glyceraldehyde 3-phosphate dehydrogenase
- HFD, high-fat diet
- HOMA-IR, homeostatic model assessment as an index of insulin resistance
- IL, interleukin
- IR, insulin receptor
- IRS, insulin receptor substrate
- Insulin
- KD, knock down
- KO, knockout
- Macrophage
- NCD, normal chow diet
- NEFA, nonesterified fatty acid
- Obesity
- PDK, phosphoinositide-dependent kinase
- PI3K, phosphatidylinositol 3-phosphate kinase
- SOCS, suppressor of cytokine signaling
- T2DM, type 2 diabetes mellitus
- Tg, transgenic
- USP
- USP, ubiquitin-specific protease
- pAkt, phosphorylated Akt
- pIRβ, phosphorylated insulin receptor β chain
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Affiliation(s)
- Natsuko Saito
- Laboratory of Veterinary Physiology, Department of Veterinary Medicine, and Laboratory of Animal Therapeutics, Japan
| | - Shunsuke Kimura
- Laboratory of Histology and Cytology, Department of Functional Morphology, Graduate School of Medical Sciences, Hokkaido University, Kita15, Nishi7, Kita-ku, Sapporo, Hokkaido 060-8638, Japan
| | - Tomomi Miyamoto
- Department of Comparative and Experimental Medicine, Graduate School of Medicine, Nagoya City University, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, Aichi 467-8601, Japan
| | - Sanae Fukushima
- Research Resources Center, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Misato Amagasa
- Laboratory of Veterinary Physiology, Department of Veterinary Medicine, and Laboratory of Animal Therapeutics, Japan
| | - Yoshinori Shimamoto
- Department of Veterinary Science, Rakuno Gakuen University, 582 Midorimachi, Bunkyodai, Ebetsu, Hokkaido 069-8501, Japan
| | - Chieko Nishioka
- Research Resources Center, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Shiki Okamoto
- Division of Endocrinology and Metabolism, National Institute for Physiological Sciences, 38 Nishigonaka Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - Chitoku Toda
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520-8063, USA
| | - Kohei Washio
- Laboratory of Veterinary Physiology, Department of Veterinary Medicine, and Laboratory of Animal Therapeutics, Japan
| | - Atsushi Asano
- Laboratory of Laboratory Animal, Department of Basic Veterinary Science, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
| | - Ichiro Miyoshi
- Department of Comparative and Experimental Medicine, Graduate School of Medicine, Nagoya City University, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, Aichi 467-8601, Japan
| | - Eiki Takahashi
- Research Resources Center, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Hiroshi Kitamura
- Laboratory of Veterinary Physiology, Department of Veterinary Medicine, and Laboratory of Animal Therapeutics, Japan.,Laboratory of Histology and Cytology, Department of Functional Morphology, Graduate School of Medical Sciences, Hokkaido University, Kita15, Nishi7, Kita-ku, Sapporo, Hokkaido 060-8638, Japan.,Department of Comparative and Experimental Medicine, Graduate School of Medicine, Nagoya City University, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, Aichi 467-8601, Japan
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Jensen VFH, Mølck AM, Chapman M, Alifrangis L, Andersen L, Lykkesfeldt J, Bøgh IB. Chronic Hyperinsulinaemic Hypoglycaemia in Rats Is Accompanied by Increased Body Weight, Hyperleptinaemia, and Decreased Neuronal Glucose Transporter Levels in the Brain. Int J Endocrinol 2017; 2017:7861236. [PMID: 28421113 PMCID: PMC5379133 DOI: 10.1155/2017/7861236] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 12/19/2016] [Accepted: 12/26/2016] [Indexed: 12/18/2022] Open
Abstract
The brain is vulnerable to hypoglycaemia due to a continuous need of energy substrates to meet its high metabolic demands. Studies have shown that severe acute insulin-induced hypoglycaemia results in oxidative stress in the rat brain, when neuroglycopenia cannot be evaded despite increased levels of cerebral glucose transporters. Compensatory measures in the brain during chronic insulin-induced hypoglycaemia are less well understood. The present study investigated how the brain of nondiabetic rats copes with chronic insulin-induced hypoglycaemia for up to eight weeks. Brain level of different substrate transporters and redox homeostasis was evaluated. Hyperinsulinaemia for 8 weeks consistently lowered blood glucose levels by 30-50% (4-6 mM versus 7-9 mM in controls). The animals had increased food consumption, body weights, and hyperleptinaemia. During infusion, protein levels of the brain neuronal glucose transporter were decreased, whereas levels of lipid peroxidation products were unchanged. Discontinued infusion was followed by transient systemic hyperglycaemia and decreased food consumption and body weight. After 4 weeks, plasma levels of lipid peroxidation products were increased, possibly as a consequence of hyperglycaemia-induced oxidative stress. The present data suggests that chronic moderate hyperinsulinaemic hypoglycaemia causes increased body weight and hyperleptinaemia. This is accompanied by decreased neuronal glucose transporter levels, which may be leptin-induced.
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Affiliation(s)
- Vivi F. H. Jensen
- Department of Veterinary Disease Biology, Section for Experimental Animal Models, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Toxicology, Safety Pharm and Pathology, Novo Nordisk A/S, Maaloev, Denmark
- *Vivi F. H. Jensen:
| | - Anne-Marie Mølck
- Department of Toxicology, Safety Pharm and Pathology, Novo Nordisk A/S, Maaloev, Denmark
| | | | - Lene Alifrangis
- Department of Development DMPK, Novo Nordisk A/S, Maaloev, Denmark
| | - Lene Andersen
- Department of Development Bioanalysis, Novo Nordisk A/S, Maaloev, Denmark
| | - Jens Lykkesfeldt
- Department of Veterinary Disease Biology, Section for Experimental Animal Models, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ingrid B. Bøgh
- Department of Toxicology, Safety Pharm and Pathology, Novo Nordisk A/S, Maaloev, Denmark
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11
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Dexamethasone Alters the Appetite Regulation via Induction of Hypothalamic Insulin Resistance in Rat Brain. Mol Neurobiol 2016; 54:7483-7496. [DOI: 10.1007/s12035-016-0251-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2016] [Accepted: 10/23/2016] [Indexed: 01/08/2023]
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Abrahamsson N, Edén Engström B, Sundbom M, Karlsson FA. Hypoglycemia in everyday life after gastric bypass and duodenal switch. Eur J Endocrinol 2015; 173:91-100. [PMID: 25899582 DOI: 10.1530/eje-14-0821] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 04/21/2015] [Indexed: 12/30/2022]
Abstract
DESIGN Gastric bypass (GBP) and duodenal switch (DS) in morbid obesity are accompanied by marked metabolic improvements, particularly in glucose control. In recent years, episodes of severe late postprandial hypoglycemia have been increasingly described in GBP patients; data in DS patients are scarce. We recruited three groups of subjects; 15 GBP, 15 DS, and 15 non-operated overweight controls to examine to what extent hypoglycemia occurs in daily life. METHODS Continuous glucose monitoring (CGM) was used during 3 days of normal activity. The glycemic variability was measured by mean amplitude of glycemic excursion and continuous overall net glycemic action. Fasting blood samples were drawn, and the patients kept a food and symptom log throughout the study. RESULTS The GBP group displayed highly variable CGM curves, and 2.9% of their time was spent in hypoglycemia (<3.3 mmol/l, or 60 mg/dl). The DS group had twice as much time in hypoglycemia (5.9%) and displayed CGM curves with little variation as well as lower HbA1c levels (29.3 vs 35.9 mmol/mol, P<0.05). Out of a total of 72 hypoglycemic episodes registered over the 3-day period, 70 (97%) occurred in the postprandial state and only about one-fifth of the hypoglycemic episodes in the GBP and DS groups were accompanied by symptoms. No hypoglycemias were seen in controls during the 3-day period. CONCLUSION Both types of bariatric surgery induce marked, but different, changes in glucose balance accompanied by frequent, but mainly unnoticed, hypoglycemic episodes. The impact and mechanism of hypoglycemic unawareness after weight-reduction surgery deserves to be clarified.
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Affiliation(s)
- Niclas Abrahamsson
- Departments of Medical SciencesSurgical SciencesUppsala University Hospital, S-751 85 Uppsala, Sweden
| | - Britt Edén Engström
- Departments of Medical SciencesSurgical SciencesUppsala University Hospital, S-751 85 Uppsala, Sweden
| | - Magnus Sundbom
- Departments of Medical SciencesSurgical SciencesUppsala University Hospital, S-751 85 Uppsala, Sweden
| | - F Anders Karlsson
- Departments of Medical SciencesSurgical SciencesUppsala University Hospital, S-751 85 Uppsala, Sweden
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13
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Diet-induced obesity impairs hypothalamic glucose sensing but not glucose hypothalamic extracellular levels, as measured by microdialysis. Nutr Diabetes 2015; 5:e162. [PMID: 26075639 PMCID: PMC4491853 DOI: 10.1038/nutd.2015.12] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 04/09/2015] [Accepted: 04/22/2015] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND/OBJECTIVES Glucose from the diet may signal metabolic status to hypothalamic sites controlling energy homeostasis. Disruption of this mechanism may contribute to obesity but its relevance has not been established. The present experiments aimed at evaluating whether obesity induced by chronic high-fat intake affects the ability of hypothalamic glucose to control feeding. We hypothesized that glucose transport to the hypothalamus as well as glucose sensing and signaling could be impaired by high-fat feeding. SUBJECTS/METHODS Female Wistar rats were studied after 8 weeks on either control or high-lard diet. Daily food intake was measured after intracerebroventricular (i.c.v.) glucose. Glycemia and glucose content of medial hypothalamus microdialysates were measured in response to interperitoneal (i.p.) glucose or meal intake after an overnight fast. The effect of refeeding on whole hypothalamus levels of glucose transporter proteins (GLUT) 1, 2 and 4, AMPK and phosphorylated AMPK levels was determined by immunoblotting. RESULTS High-fat rats had higher body weight and fat content and serum leptin than control rats, but normal insulin levels and glucose tolerance. I.c.v. glucose inhibited food intake in control but failed to do so in high-fat rats. Either i.p. glucose or refeeding significantly increased glucose hypothalamic microdialysate levels in the control rats. These levels showed exacerbated increases in the high-fat rats. GLUT1 and 4 levels were not affected by refeeding. GLUT2 levels decreased and phosphor-AMPK levels increased in the high-fat rats but not in the controls. CONCLUSIONS The findings suggest that, in the high-fat rats, a defective glucose sensing by decreased GLUT2 levels contributed to an inappropriate activation of AMPK after refeeding, despite increased extracellular glucose levels. These derangements were probably involved in the abolition of hypophagia in response to i.c.v. glucose. It is proposed that 'glucose resistance' in central sites of feeding control may be relevant in the disturbances of energy homeostasis induced by high-fat feeding.
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14
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Sonneville R, Vanhorebeek I, den Hertog HM, Chrétien F, Annane D, Sharshar T, Van den Berghe G. Critical illness-induced dysglycemia and the brain. Intensive Care Med 2014; 41:192-202. [PMID: 25465908 DOI: 10.1007/s00134-014-3577-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 11/19/2014] [Indexed: 01/04/2023]
Abstract
PURPOSE Dysglycemia is a characteristic feature of critical illness associated with adverse outcome. Whether dysglycemia contributes to brain dysfunction during critical illness and long-term neurological complications is unclear. We give an overview of glucose metabolism in the brain and review the literature on critical illness-induced dysglycemia and the brain. METHODS Medline database search using relevant search terms on dysglycemia, critical illness, acute brain injury/dysfunction, and randomized controlled trial. RESULTS Hyperglycemia has been associated with deleterious effects on the nervous system. Underlying mechanisms in critical illness remain largely speculative and are often extrapolated from knowledge in diabetes mellitus. Increased hyperglycemia-induced blood-brain barrier permeability, oxidative stress, and microglia activation may play a role and compromise neuronal and glial cell integrity. Hypoglycemia is feared as critically ill patients cannot recognize or communicate hypoglycemic symptoms, which furthermore are masked by sedation and analgesia. However, observational data on the impact of brief hypoglycemia on the brain in critical illness are controversial. Secondary analysis of two large randomized studies suggested neuroprotection by strict glycemic control with insulin during intensive care, with lowered intracranial pressure, reduction of seizures, and better long-term rehabilitation in patients with isolated brain injury, and reduced incidence of critical illness polyneuromyopathy in the general critically ill patient population. Several subsequent studies failed to reproduce neurological benefit, likely explained by methodological issues, which include divergent achieved glucose levels and inaccurate glucose monitoring tools. CONCLUSIONS Preventing hyperglycemia during critical illness holds promise as a neuroprotective strategy to preserve brain cell viability and prevent acute brain dysfunction and long-term cognitive impairment in survivors.
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Affiliation(s)
- Romain Sonneville
- Clinical Department and Laboratory of Intensive Care Medicine, Division of Cellular and Molecular Medicine, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
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15
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Jensen VFH, Bøgh IB, Lykkesfeldt J. Effect of insulin-induced hypoglycaemia on the central nervous system: evidence from experimental studies. J Neuroendocrinol 2014; 26:123-50. [PMID: 24428753 DOI: 10.1111/jne.12133] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 12/13/2013] [Accepted: 01/08/2014] [Indexed: 12/12/2022]
Abstract
Insulin-induced hypoglycaemia (IIH) is a major acute complication in type 1 as well as in type 2 diabetes, particularly during intensive insulin therapy. The brain plays a central role in the counter-regulatory response by eliciting parasympathetic and sympathetic hormone responses to restore normoglycaemia. Brain glucose concentrations, being approximately 15-20% of the blood glucose concentration in humans, are rigorously maintained during hypoglycaemia through adaptions such as increased cerebral glucose transport, decreased cerebral glucose utilisation and, possibly, by using central nervous system glycogen as a glucose reserve. However, during sustained hypoglycaemia, the brain cannot maintain a sufficient glucose influx and, as the cerebral hypoglycaemia becomes severe, electroencephalogram changes, oxidative stress and regional neuronal death ensues. With particular focus on evidence from experimental studies on nondiabetic IIH, this review outlines the central mechanisms behind the counter-regulatory response to IIH, as well as cerebral adaption to avoid sequelae of cerebral neuroglycopaenia, including seizures and coma.
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Affiliation(s)
- V F H Jensen
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Diabetes Toxicology and Safety Pharmacology, Novo Nordisk A/S, Maaloev, Denmark
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16
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Prasad S, Sajja RK, Naik P, Cucullo L. Diabetes Mellitus and Blood-Brain Barrier Dysfunction: An Overview. ACTA ACUST UNITED AC 2014; 2:125. [PMID: 25632404 DOI: 10.4172/2329-6887.1000125] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A host of diabetes-related insults to the central nervous system (CNS) have been clearly documented in type-1 and -2 diabetic patients as well as experimental animal models. These host of neurological disorders encompass hemodynamic impairments (e.g., stroke), vascular dementia, cognitive deficits (mild to moderate), as well as a number of neurochemical, electrophysiological and behavioral alterations. The underlying causes of diabetes-induced CNS complications are multifactorial and are relatively little understood although it is now evident that blood-brain barrier (BBB) damage plays a significant role in diabetes-dependent CNS disorders. Changes in plasma glucose levels (hyper- or hypoglycemia) have been associated with altered BBB transport functions (e.g., glucose, insulin, choline, amino acids, etc.), integrity (tight junction disruption), and oxidative stress in the CNS microcapillaries. Last two implicating a potential causal role for upregulation and activation of the receptor for advanced glycation end products (RAGE). This type I membrane-protein also transports amyloid-beta (Aβ) from the blood into the brain across the BBB thus, establishing a link between type 2 diabetes mellitus (T2DM) and Alzheimer's disease (AD, also referred to as "type 3 diabetes"). Hyperglycemia has been associated with progression of cerebral ischemia and the consequent enhancement of secondary brain injury. Difficulty in detecting vascular impairments in the large, heterogeneous brain microvascular bed and dissecting out the impact of hyper- and hypoglycemia in vivo has led to controversial results especially with regard to the effects of diabetes on BBB. In this article, we review the major findings and current knowledge with regard to the impact of diabetes on BBB integrity and function as well as specific brain microvascular effects of hyper- and hypoglycemia.
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Affiliation(s)
- Shikha Prasad
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health, Texas, USA
| | - Ravi K Sajja
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health, Texas, USA
| | - Pooja Naik
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health, Texas, USA
| | - Luca Cucullo
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health, Texas, USA ; Vascular Drug research Center, Texas Tech University Health Sciences Center, Amarillo, Texas, USA
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17
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Kitamura H, Kimura S, Shimamoto Y, Okabe J, Ito M, Miyamoto T, Naoe Y, Kikuguchi C, Meek B, Toda C, Okamoto S, Kanehira K, Hase K, Watarai H, Ishizuka M, El-Osta A, Ohara O, Miyoshi I. Ubiquitin-specific protease 2-69 in macrophages potentially modulates metainflammation. FASEB J 2013; 27:4940-53. [PMID: 24005904 DOI: 10.1096/fj.13-233528] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Macrophages play a critical role in chronic inflammation and metabolic diseases. We identified a longer splice variant of ubiquitin specific protease (USP) 2-69 as a novel molecule that modulates pathways implicated in metabolic disorders. Expression levels of aP2/FABP4 and PAI-1/SERPINE1 genes were increased by 4- and 1.8-fold, respectively, after short hairpin RNA-mediated knockdown (KD) of the USP2 gene, and such expression was alleviated by overexpression of USP2-69 in human myeloid cell lines. Supernatants derived from USP2-KD cells induced IL6 (∼6-fold) and SAA3 (∼15-fold) in 3T3-L1 adipocytes to suggest the anti-inflammatory properties of USP2. In addition, we observed a 30% decrease in the number of macrophages in mesenteric adipose tissue derived from USP2-69 transgenic mice fed a high-fat diet for 14 wk compared with that in their C57BL/6 littermates (P<0.01), which was consistent with a ∼40% decrease in transcription of aP2 and PAI-1. The aP2 locus exhibited elevated chromatin accessibility (>2.1-fold), methylation of histone H3 lysine 4 (>4.5-fold), and acetylation of histone H4 (>2.5-fold) in USP2-KD cells. Transfection of isopeptidase-mutated USP2-69 did not alter chromatin conformation on the aP2 locus in USP2-KD cells. Our results suggest that USP2-69 suppresses meta-inflammatory molecules involved in the development of type-2 diabetes.
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Affiliation(s)
- Hiroshi Kitamura
- 1Department of Comparative and Experimental Medicine, Graduate School of Medical Sciences, Nagoya City University, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan.
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18
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Vora M, Shah M, Ostafi S, Onken B, Xue J, Ni JZ, Gu S, Driscoll M. Deletion of microRNA-80 activates dietary restriction to extend C. elegans healthspan and lifespan. PLoS Genet 2013; 9:e1003737. [PMID: 24009527 PMCID: PMC3757059 DOI: 10.1371/journal.pgen.1003737] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2013] [Accepted: 07/07/2013] [Indexed: 12/12/2022] Open
Abstract
Caloric/dietary restriction (CR/DR) can promote longevity and protect against age-associated disease across species. The molecular mechanisms coordinating food intake with health-promoting metabolism are thus of significant medical interest. We report that conserved Caenorhabditis elegans microRNA-80 (mir-80) is a major regulator of the DR state. mir-80 deletion confers system-wide healthy aging, including maintained cardiac-like and skeletal muscle-like function at advanced age, reduced accumulation of lipofuscin, and extended lifespan, coincident with induction of physiological features of DR. mir-80 expression is generally high under ad lib feeding and low under food limitation, with most striking food-sensitive expression changes in posterior intestine. The acetyltransferase transcription co-factor cbp-1 and interacting transcription factors daf-16/FOXO and heat shock factor-1 hsf-1 are essential for mir-80(Δ) benefits. Candidate miR-80 target sequences within the cbp-1 transcript may confer food-dependent regulation. Under food limitation, lowered miR-80 levels directly or indirectly increase CBP-1 protein levels to engage metabolic loops that promote DR.
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Affiliation(s)
- Mehul Vora
- Department of Molecular Biology and Biochemistry, Nelson Biological Laboratories, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Mitalie Shah
- Department of Molecular Biology and Biochemistry, Nelson Biological Laboratories, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Silvana Ostafi
- Department of Molecular Biology and Biochemistry, Nelson Biological Laboratories, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Brian Onken
- Department of Molecular Biology and Biochemistry, Nelson Biological Laboratories, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Jian Xue
- Department of Molecular Biology and Biochemistry, Nelson Biological Laboratories, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Julie Zhouli Ni
- Department of Molecular Biology and Biochemistry, Nelson Biological Laboratories, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Sam Gu
- Department of Molecular Biology and Biochemistry, Nelson Biological Laboratories, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Monica Driscoll
- Department of Molecular Biology and Biochemistry, Nelson Biological Laboratories, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
- * E-mail:
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Reno CM, Litvin M, Clark AL, Fisher SJ. Defective counterregulation and hypoglycemia unawareness in diabetes: mechanisms and emerging treatments. Endocrinol Metab Clin North Am 2013; 42:15-38. [PMID: 23391237 PMCID: PMC3568263 DOI: 10.1016/j.ecl.2012.11.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
For people with diabetes, hypoglycemia remains the limiting factor in achieving glycemic control. This article reviews recent advances in how the brain senses and responds to hypoglycemia. Novel mechanisms by which individuals with insulin-treated diabetes develop hypoglycemia unawareness and impaired counterregulatory responses are outlined. Prevention strategies for reducing the incidence of hypoglycemia are discussed.
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Affiliation(s)
- Candace M. Reno
- Division of Endocrinology, Metabolism, & Lipid Research, Department of Medicine, Washington University, St. Louis, MO
| | - Marina Litvin
- Division of Endocrinology, Metabolism, & Lipid Research, Department of Medicine, Washington University, St. Louis, MO
| | - Amy L. Clark
- Division of Endocrinology and Diabetes, Department of Pediatrics, Washington University, St. Louis, MO
| | - Simon J. Fisher
- Division of Endocrinology, Metabolism, & Lipid Research, Department of Medicine, Washington University, St. Louis, MO
- Department of Cell Biology and Physiology, Washington University, St. Louis, MO
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20
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Fuente-Martín E, García-Cáceres C, Granado M, de Ceballos ML, Sánchez-Garrido MÁ, Sarman B, Liu ZW, Dietrich MO, Tena-Sempere M, Argente-Arizón P, Díaz F, Argente J, Horvath TL, Chowen JA. Leptin regulates glutamate and glucose transporters in hypothalamic astrocytes. J Clin Invest 2012; 122:3900-13. [PMID: 23064363 DOI: 10.1172/jci64102] [Citation(s) in RCA: 155] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Accepted: 08/27/2012] [Indexed: 01/08/2023] Open
Abstract
Glial cells perform critical functions that alter the metabolism and activity of neurons, and there is increasing interest in their role in appetite and energy balance. Leptin, a key regulator of appetite and metabolism, has previously been reported to influence glial structural proteins and morphology. Here, we demonstrate that metabolic status and leptin also modify astrocyte-specific glutamate and glucose transporters, indicating that metabolic signals influence synaptic efficacy and glucose uptake and, ultimately, neuronal function. We found that basal and glucose-stimulated electrical activity of hypothalamic proopiomelanocortin (POMC) neurons in mice were altered in the offspring of mothers fed a high-fat diet. In adulthood, increased body weight and fasting also altered the expression of glucose and glutamate transporters. These results demonstrate that whole-organism metabolism alters hypothalamic glial cell activity and suggest that these cells play an important role in the pathology of obesity.
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Affiliation(s)
- Esther Fuente-Martín
- Hospital Infantil Universitario Niño Jesús, Department of Endocrinology, Instituto de Investigación La Princesa, Madrid, Spain
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21
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Spiller F, Carlos D, Souto FO, de Freitas A, Soares FS, Vieira SM, Paula FJ, Alves-Filho JC, Cunha FQ. α1-Acid glycoprotein decreases neutrophil migration and increases susceptibility to sepsis in diabetic mice. Diabetes 2012; 61:1584-91. [PMID: 22415874 PMCID: PMC3357278 DOI: 10.2337/db11-0825] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The mechanisms underlying immune deficiency in diabetes are largely unknown. In the present study, we demonstrate that diabetic mice are highly susceptible to polymicrobial sepsis due to reduction in rolling, adhesion, and migration of leukocytes to the focus of infection. In addition, after sepsis induction, CXCR2 was strongly downregulated in neutrophils from diabetic mice compared with nondiabetic mice. Furthermore, CXCR2 downregulation was associated with increased G-protein-coupled receptor kinase 2 (GRK2) expression in these cells. Different from nondiabetic mice, diabetic animals submitted to mild sepsis displayed a significant augment in α1-acid glycoprotein (AGP) hepatic mRNA expression and serum protein levels. Administration of AGP in nondiabetic mice subjected to mild sepsis inhibited the neutrophil migration to the focus of infection, as well as induced l-selectin shedding and rise in CD11b of blood neutrophils. Insulin treatment of diabetic mice reduced mortality rate, prevented the failure of neutrophil migration, impaired GRK2-mediated CXCR2 downregulation, and decreased the generation of AGP. Finally, administration of AGP abolished the effect of insulin treatment in diabetic mice. Together, these data suggest that AGP may be involved in reduction of neutrophil migration and increased susceptibility to sepsis in diabetic mice.
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Affiliation(s)
- Fernando Spiller
- Department of Pharmacology, Biological Sciences Center, Federal University of Santa Catarina, Florianópolis, Santa Catarina, Brazil
| | - Daniela Carlos
- Department of Pharmacology, School of Medicine Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Fabrício O. Souto
- Department of Biochemistry and Immunology, School of Medicine Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Andressa de Freitas
- Department of Pharmacology, School of Medicine Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Fernanda S. Soares
- Department of Pharmacology, Biological Sciences Center, Federal University of Santa Catarina, Florianópolis, Santa Catarina, Brazil
| | - Silvio M. Vieira
- Department of Pharmacology, School of Medicine Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Francisco J.A. Paula
- Department of Clinical Medicine, School of Medicine Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - José C. Alves-Filho
- Department of Pharmacology, School of Medicine Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Fernando Q. Cunha
- Department of Pharmacology, School of Medicine Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
- Corresponding author: Fernando Q. Cunha,
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Yang L, Isoda F, Yen K, Kleopoulos SP, Janssen W, Fan X, Mastaitis J, Dunn-Meynell A, Levin B, McCrimmon R, Sherwin R, Musatov S, Mobbs CV. Hypothalamic Fkbp51 is induced by fasting, and elevated hypothalamic expression promotes obese phenotypes. Am J Physiol Endocrinol Metab 2012; 302:E987-91. [PMID: 22318949 PMCID: PMC3330722 DOI: 10.1152/ajpendo.00474.2011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To discover hypothalamic genes that might play a role in regulating energy balance, we carried out a microarray screen for genes induced by a 48-h fast in male C57Bl/6J mouse hypothalamus. One such gene was Fkbp51 (FK506 binding protein 5; Locus NP_034350). The product of this gene is of interest because it blocks glucocorticoid action, suggesting that fasting-induced elevation of this gene in the hypothalamus may reduce glucocorticoid negative feedback, leading to elevated glucocorticoid levels, thus promoting obese phenotypes. Subsequent analysis demonstrated that a 48-h fast induces Fkbp51 in ventromedial, paraventricular, and arcuate hypothalamic nuclei of mice and rats. To assess if hypothalamic Fkbp51 promotes obesity, the gene was transferred to the hypothalamus via an adeno-associated virus vector. Within 2 wk following Fkbp51 overexpression, mice on a high-fat diet exhibited elevated body weight, without hyperphagia, relative to mice receiving the control mCherry vector. Body weight remained elevated for more than 8 wk and was associated with elevated corticosterone and impaired glucose tolerance. These studies suggest that elevated hypothalamic Fkbp51 promotes obese phenotypes.
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Affiliation(s)
- Linda Yang
- Fishberg Dept. of Neuroscience, Mount Sinai School of Medicine, New York, NY 10029, USA
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Poplawski MM, Mastaitis JW, Mobbs CV. Naloxone, but not valsartan, preserves responses to hypoglycemia after antecedent hypoglycemia: role of metabolic reprogramming in counterregulatory failure. Diabetes 2011; 60:39-46. [PMID: 20811039 PMCID: PMC3012195 DOI: 10.2337/db10-0326] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE Hypoglycemia-associated autonomic failure (HAAF) constitutes one of the main clinical obstacles to optimum treatment of type 1 diabetes. Neurons in the ventromedial hypothalamus are thought to mediate counterregulatory responses to hypoglycemia. We have previously hypothesized that hypoglycemia-induced hypothalamic angiotensin might contribute to HAAF, suggesting that the angiotensin blocker valsartan might prevent HAAF. On the other hand, clinical studies have demonstrated that the opioid receptor blocker naloxone ameliorates HAAF. The goal of this study was to generate novel hypothalamic markers of hypoglycemia and use them to assess mechanisms mediating HAAF and its reversal. RESEARCH DESIGN AND METHODS Quantitative PCR was used to validate a novel panel of hypothalamic genes regulated by hypoglycemia. Mice were exposed to one or five episodes of insulin-induced hypoglycemia, with or without concurrent exposure to valsartan or naloxone. Corticosterone, glucagon, epinephrine, and hypothalamic gene expression were assessed after the final episode of hypoglycemia. RESULTS A subset of hypothalamic genes regulated acutely by hypoglycemia failed to respond after repetitive hypoglycemia. Responsiveness of a subset of these genes was preserved by naloxone but not valsartan. Notably, hypothalamic expression of four genes, including pyruvate dehydrogenase kinase 4 and glycerol 3-phosphate dehydrogenase 1, was acutely induced by a single episode of hypoglycemia, but not after antecedent hypoglycemia; naloxone treatment prevented this failure. Similarly, carnitine palmitoyltransferase-1 was inhibited after repetitive hypoglycemia, and this inhibition was prevented by naloxone. Repetitive hypoglycemia also caused a loss of hypoglycemia-induced elevation of glucocorticoid secretion, a failure prevented by naloxone but not valsartan. CONCLUSIONS Based on these observations we speculate that acute hypoglycemia induces reprogramming of hypothalamic metabolism away from glycolysis toward β-oxidation, HAAF is associated with a reversal of this reprogramming, and naloxone preserves some responses to hypoglycemia by preventing this reversal.
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Affiliation(s)
- Michal M. Poplawski
- Fishberg Center for Neurobiology, Mount Sinai School of Medicine, New York, New York
| | - Jason W. Mastaitis
- Department of Internal Medicine, The Anlyan Center, Yale University School of Medicine, New Haven, Connecticut
| | - Charles V. Mobbs
- Fishberg Center for Neurobiology, Mount Sinai School of Medicine, New York, New York
- Corresponding author: Charles V. Mobbs,
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24
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Zhang M, Poplawski M, Yen K, Cheng H, Bloss E, Zhu X, Patel H, Mobbs CV. Role of CBP and SATB-1 in aging, dietary restriction, and insulin-like signaling. PLoS Biol 2009; 7:e1000245. [PMID: 19924292 PMCID: PMC2774267 DOI: 10.1371/journal.pbio.1000245] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Accepted: 10/09/2009] [Indexed: 01/14/2023] Open
Abstract
Increased transcriptional complex activity, or pharmacological mimics of increased complex activity, predict lifespan in mice and mediate the protective effects of dietary restriction during aging. How dietary restriction (DR) increases lifespan and decreases disease burden are questions of major interest in biomedical research. Here we report that hypothalamic expression of CREB-binding protein (CBP) and CBP-binding partner Special AT-rich sequence binding protein 1 (SATB-1) is highly correlated with lifespan across five strains of mice, and expression of these genes decreases with age and diabetes in mice. Furthermore, in Caenorhabditis elegans, cbp-1 is induced by bacterial dilution DR (bDR) and the daf-2 mutation, and cbp-1 RNAi specifically in adults completely blocks lifespan extension by three distinct protocols of DR, partially blocks lifespan extension by the daf-2 mutation but not of cold, and blocks delay of other age-related pathologies by bDR. Inhibiting the C. elegans ortholog of SATB-1 and CBP-binding partners daf-16 and hsf-1 also attenuates lifespan extension by bDR, but not other protocols of DR. In a transgenic Aβ42 model of Alzheimer's disease, cbp-1 RNAi prevents protective effects of bDR and accelerates Aβ42-related pathology. Furthermore, consistent with the function of CBP as a histone acetyltransferase, drugs that enhance histone acetylation increase lifespan and reduce Aβ42-related pathology, protective effects completely blocked by cbp-1 RNAi. Other factors implicated in lifespan extension are also CBP-binding partners, suggesting that CBP constitutes a common factor in the modulation of lifespan and disease burden by DR and the insulin/IGF1 signaling pathway. The simple manipulation of dietary restriction (DR) (reduction of caloric intake by about 30% in rodents) produces robust increases in lifespan and slows the development of almost all age-related diseases, including cancer and neurological diseases. This relationship between dietary restriction and longevity is observed in most models in which the effect of DR has been tested. Thus, understanding how DR produces its protective mechanisms would have potentially profound implications for the treatment of age-related diseases, including possibly the development of a “magic bullet” for these diseases. In the present study we have discovered that DR induces a transcription factor, CBP, and additional factors that work with CBP to control the expression of other genes involved in determination of lifespan. When we blocked the DR-mediated increase in CBP and associated factors, we blocked all the protective effects of DR on lifespan extension, on the slowed rate of aging, and on protection against pathology in a model of Alzheimer's disease. Further, in mice expression of CBP and a CBP-interacting factor positively predicted lifespan, and expression of both factors decreased with age and in diabetes. Finally, pharmacological manipulations that mimicked enhanced CBP activity increased lifespan and reduced pathology in a model of Alzheimer's disease.
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Affiliation(s)
- Minhua Zhang
- Department of Neuroscience, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Michal Poplawski
- Department of Neuroscience, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Kelvin Yen
- Department of Neuroscience, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Hui Cheng
- Department of Neuroscience, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Erik Bloss
- Department of Neuroscience, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Xiao Zhu
- Department of Neuroscience, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Harshil Patel
- Department of Neuroscience, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Charles V. Mobbs
- Department of Neuroscience, Mount Sinai School of Medicine, New York, New York, United States of America
- Department of Geriatrics, Mount Sinai School of Medicine, New York, New York, United States of America
- * E-mail:
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25
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Estradiol impairs hypothalamic molecular responses to hypoglycemia. Brain Res 2009; 1280:77-83. [PMID: 19445909 DOI: 10.1016/j.brainres.2009.05.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Revised: 04/12/2009] [Accepted: 05/08/2009] [Indexed: 11/20/2022]
Abstract
In rats and humans estradiol attenuates neuroendocrine responses to hypoglycemia. Since neuroendocrine responses to hypoglycemia are mediated by hypothalamic neurons, we assessed if estradiol attenuates hypoglycemia-induced gene expression in the hypothalamus in female ovariectomized mice. As expected, estradiol-implanted ovariectomized mice exhibited increased plasma estradiol, increased uterine weight, decreased body weight, decreased visceral adiposity, and enhanced glucose tolerance with decreased plasma insulin. Estradiol-implanted mice exhibited attenuated hypoglycemia-induced gene expression of both glucose transporter 1 (Glut1) and inhibitor of kappa beta signaling (IkappaB) in the hypothalamus but not in the liver. Estradiol also attenuated hypoglycemia-induced plasma glucagon, pituitary proopiomelanocortin (POMC), and adrenal c-fos, consistent with impaired counterregulatory responses to hypoglycemia. In addition, estradiol inhibited hypothalamic expression of carnitine palmitoyltransferase (CPT1a and CPT1c) and pyruvate dehydrogenase kinase 4 (PDK4), effects that would be expected to enhance the accumulation of long-chain fatty acids and glycolysis. Taken together, these findings suggest hypothalamic mechanisms mediating attenuation of hypoglycemia-induced neuroendocrine responses.
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26
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Jiang K, Patel NA, Watson JE, Apostolatos H, Kleiman E, Hanson O, Hagiwara M, Cooper DR. Akt2 regulation of Cdc2-like kinases (Clk/Sty), serine/arginine-rich (SR) protein phosphorylation, and insulin-induced alternative splicing of PKCbetaII messenger ribonucleic acid. Endocrinology 2009; 150:2087-97. [PMID: 19116344 PMCID: PMC2671910 DOI: 10.1210/en.2008-0818] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Serine/arginine-rich (SR) proteins play essential roles in the constitutive and regulated splicing of precursor mRNAs. Phosphorylation of the arginine/serine dipeptide-rich (RS) domain by SR protein kinases such as Cdc2-like kinases (Clk/Sty) modulates their subcellular localization and activation. However, it remains unclear how these kinases and their target SR proteins are regulated by extracellular signals. Regulation of protein kinase C betaII (PKCbetaII) pre-mRNA alternative splicing via exon inclusion by Akt2, a central kinase in insulin action, involves phosphorylation of SR proteins. Here we showed that Akt2, in response to insulin, resulted in phosphorylation of Clk/Sty, which then altered SR protein phosphorylation in concert with Akt2. Insulin-stimulated PKCbetaII pre-mRNA splicing was blocked by Clk/Sty and phosphatidylinositol-3-kinase inhibitors, and diabetic Akt2-null mouse tissues had impaired phospho-Clk/Sty, SR protein phosphorylation, and PKCbetaII expression. Furthermore, we observed that Akt2 phosphorylated several SR proteins distinct from Clk/Sty in response to insulin. Akt2-catalyzed phosphorylation of Clk/Sty and SR proteins revealed a role for both kinases in splicing regulation indicating dual functions for Akt2 in response to insulin in this pathway.
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Affiliation(s)
- Kun Jiang
- Department of Molecular Medicine, University of South Florida College of Medicine, Tampa, Florida 33612, USA
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27
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Obrenovitch TP. Molecular physiology of preconditioning-induced brain tolerance to ischemia. Physiol Rev 2008; 88:211-47. [PMID: 18195087 DOI: 10.1152/physrev.00039.2006] [Citation(s) in RCA: 170] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Ischemic tolerance describes the adaptive biological response of cells and organs that is initiated by preconditioning (i.e., exposure to stressor of mild severity) and the associated period during which their resistance to ischemia is markedly increased. This topic is attracting much attention because preconditioning-induced ischemic tolerance is an effective experimental probe to understand how the brain protects itself. This review is focused on the molecular and related functional changes that are associated with, and may contribute to, brain ischemic tolerance. When the tolerant brain is subjected to ischemia, the resulting insult severity (i.e., residual blood flow, disruption of cellular transmembrane gradients) appears to be the same as in the naive brain, but the ensuing lesion is substantially reduced. This suggests that the adaptive changes in the tolerant brain may be primarily directed against postischemic and delayed processes that contribute to ischemic damage, but adaptive changes that are beneficial during the subsequent test insult cannot be ruled out. It has become clear that multiple effectors contribute to ischemic tolerance, including: 1) activation of fundamental cellular defense mechanisms such as antioxidant systems, heat shock proteins, and cell death/survival determinants; 2) responses at tissue level, especially reduced inflammatory responsiveness; and 3) a shift of the neuronal excitatory/inhibitory balance toward inhibition. Accordingly, an improved knowledge of preconditioning/ischemic tolerance should help us to identify neuroprotective strategies that are similar in nature to combination therapy, hence potentially capable of suppressing the multiple, parallel pathophysiological events that cause ischemic brain damage.
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Affiliation(s)
- Tihomir Paul Obrenovitch
- Division of Pharmacology, School of Life Sciences, University of Bradford, Bradford, United Kingdom.
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28
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Cheng H, Isoda F, Belsham DD, Mobbs CV. Inhibition of agouti-related peptide expression by glucose in a clonal hypothalamic neuronal cell line is mediated by glycolysis, not oxidative phosphorylation. Endocrinology 2008; 149:703-10. [PMID: 17974626 DOI: 10.1210/en.2007-0772] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The regulation of neuroendocrine electrical activity and gene expression by glucose is mediated through several distinct metabolic pathways. Many studies have implicated AMP and ATP as key metabolites mediating neuroendocrine responses to glucose, especially through their effects on AMP-activated protein kinase (AMPK), but other studies have suggested that glycolysis, and in particular the cytoplasmic conversion of nicotinamide adenine dinucleotide (NAD+) to reduced NAD (NADH), may play a more important role than oxidative phosphorylation for some effects of glucose. To address these molecular mechanisms further, we have examined the regulation of agouti-related peptide (AgRP) in a clonal hypothalamic cell line, N-38. AgRP expression was induced monotonically as glucose concentrations decreased from 10 to 0.5 mm glucose and with increasing concentrations of glycolytic inhibitors. However, neither pyruvate nor 3-beta-hydroxybutyrate mimicked the effect of glucose to reduce AgRP mRNA, but on the contrary, produced the opposite effect of glucose and actually increased AgRP mRNA. Nevertheless, 3beta-hydroxybutyrate mimicked the effect of glucose to increase ATP and to decrease AMPK phosphorylation. Similarly, inhibition of AMPK by RNA interference increased, and activation of AMPK decreased, AgRP mRNA. Additional studies demonstrated that neither the hexosamine nor the pentose/carbohydrate response element-binding protein pathways mediate the effects of glucose on AgRP expression. These studies do not support that either ATP or AMPK mediate effects of glucose on AgRP in this hypothalamic cell line but support a role for glycolysis and, in particular, NADH. These studies support that cytoplasmic or nuclear NADH, uniquely produced by glucose metabolism, mediates effects of glucose on AgRP expression.
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Affiliation(s)
- Hui Cheng
- Fishberg Department of Neuroscience, Mount Sinai School of Medicine, New York, NY 10029, USA
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29
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Tsukuda K, Mogi M, Li JM, Iwanami J, Min LJ, Sakata A, Fujita T, Iwai M, Horiuchi M. Diabetes-associated cognitive impairment is improved by a calcium channel blocker, nifedipine. Hypertension 2008; 51:528-33. [PMID: 18195165 DOI: 10.1161/hypertensionaha.107.101634] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Nifedipine, a calcium channel blocker, has been reported to exert pleiotropic effects on atherosclerosis, mainly through its antioxidative properties. However, the effect of the calcium channel blocker on cognitive impairment associated with type 2 diabetes mellitus is not well known. Here, we examined the possibility that a calcium channel blocker could improve cognitive function in a type 2 diabetic mouse model, KK-A(y). KK-A(y) mice subjected to 20 trials of a passive avoidance task every week from 7 weeks of age exhibited impairment of the increase in avoidance rate and, moreover, exaggeration of its age-dependent decline, especially after 12 weeks of age. Oral administration of nifedipine at a nonhypotensive dose (0.001% in laboratory chow) to KK-A(y) mice from 10 weeks of age improved cognitive function. Nifedipine treatment decreased serum insulin level to one fifth of that in KK-A(y) mice without nifedipine. Moreover, nifedipine treatment significantly reduced superoxide anion production in the brain. Furthermore, treatment with nifedipine markedly reduced the mRNA level of Id-1, inhibitor of neural differentiation, in the brain hippocampus. We also observed the increase in blood flow in the brain in KK-A(y) mice with nifedipine treatment compared with nontreated mice. Taken together, our findings suggest that nifedipine ameliorates impaired cognitive function in type 2 diabetic mice, at least because of attenuation of hyperinsulinemia and superoxide production in the brain and possible upregulation of the neural differentiation-controlling gene, Id-1.
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Affiliation(s)
- Kana Tsukuda
- Department of Molecular Cardiovascular Biology and Pharmacology, Ehime University, Graduate School of Medicine, Shitsukawa, Tohon, Ehime 791-0295, Japan
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30
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Chu TT, Fink MY, Mong JA, John G, Auger AP, Ge Y, Sealfon SC. Effective use of microarrays in neuroendocrine research. J Neuroendocrinol 2007; 19:145-61. [PMID: 17280588 DOI: 10.1111/j.1365-2826.2006.01523.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The development of microarray technology makes it possible to simultaneously assay the expression level of hundreds to tens of thousands of mRNA transcripts in one experiment. Genome-wide transcriptional analysis has increasing importance for many areas of neuroendocrinology research. The expense and technical complexity of microarray experiments can make it difficult to navigate the terrain of rival platforms and technologies. In this review, we provide a practical view and comparison of various microarray technologies. Affymetrix arrays, high-density cDNA arrays, membrane arrays and experimental design and data analysis are all discussed by researchers currently using these techniques to study gene regulation in neuroendocrine tissues.
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Affiliation(s)
- T T Chu
- Department of Pharmacology and Biological Chemistry, Mount Sinai School of Medicine, New York, NY 10029, USA
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31
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Wu JJ, Roth RJ, Anderson EJ, Hong EG, Lee MK, Choi CS, Neufer PD, Shulman GI, Kim JK, Bennett AM. Mice lacking MAP kinase phosphatase-1 have enhanced MAP kinase activity and resistance to diet-induced obesity. Cell Metab 2006; 4:61-73. [PMID: 16814733 DOI: 10.1016/j.cmet.2006.05.010] [Citation(s) in RCA: 174] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2005] [Revised: 04/07/2006] [Accepted: 05/18/2006] [Indexed: 12/31/2022]
Abstract
The mitogen-activated protein kinases (MAPK) play critical roles in the pathogenesis of diabetes and obesity. The MAPKs are inactivated by MAPK phosphatases (MKPs) either in the cytosol or nucleus. Here we show that mice lacking the nuclear-localized MKP, MKP-1 (mkp-1(-/-)), have enhanced Erk, p38 MAPK and c-Jun NH(2)-terminal kinase (JNK) activities in insulin-responsive tissues as compared with wild-type mice. Although JNK promotes insulin resistance, mkp-1(-/-) mice exhibited unimpaired insulin-mediated signaling and glucose homeostasis. We reconciled these results by demonstrating that in mkp-1(-/-) mice, JNK activity was increased in the nucleus, but not the cytosol. Significantly, mkp-1(-/-) mice are resistant to diet-induced obesity due to enhanced energy expenditure, but succumb to glucose intolerance on a high fat diet. These results suggest that nuclear regulation of the MAPKs by MKP-1 is essential for the management of metabolic homeostasis in a manner that is spatially uncoupled from the cytosolic actions of the MAPKs.
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Affiliation(s)
- J Julie Wu
- Department of Pharmacology, Section of Endocrinology and Metabolism, Yale University School of Medicine, New Haven, Connecticut 06520, USA
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32
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Criego AB, Tkac I, Kumar A, Thomas W, Gruetter R, Seaquist ER. Brain glucose concentrations in healthy humans subjected to recurrent hypoglycemia. J Neurosci Res 2006; 82:525-30. [PMID: 16235252 DOI: 10.1002/jnr.20654] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mechanisms responsible for hypoglycemia unawareness remain unknown. Previously, we found that patients with type 1 diabetes and hypoglycemia unawareness had increased brain glucose concentrations as measured by (1)H-magnetic resonance spectroscopy (MRS) compared with controls measured under the same metabolic condition, suggesting that an alteration in brain glucose transport and/or metabolism may play a role in the pathogenesis of hypoglycemia unawareness. To determine whether the brain glucose concentration is altered in normal subjects subjected to recurrent hypoglycemia, we compared the brain glucose concentrations measured in healthy subjects after three episodes of hypoglycemia to blunt the counterregulatory response over 24 hr and compared this value with that measured at a time remote from the antecedent hypoglycemia protocol. Sixteen subjects (9 M/7 F, age 36 +/- 10 years, mean +/- SD) underwent three hypoglycemic clamps for 30 min at 8 AM (0 hr), 5 PM (9 hr), and 7 AM (24 hr). After the third hypoglycemic clamp, subjects underwent a hyperglycemic clamp during which brain glucose concentration was measured by MRS at 4 T. Brain glucose concentration after repeated hypoglycemia was not different from the brain glucose concentration measured in the same subjects during a control study (5.1 +/- 0.8 vs. 4.5 +/- 0.5 mumol/g wet weight, respectively, P = 0.05). These observations suggest that brain glucose transport or metabolism is not altered following short episodes of recurrent hypoglycemia in healthy human volunteers.
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Affiliation(s)
- Amy B Criego
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis, USA
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Mobbs CV, Mastaitis JW, Zhang M, Isoda F, Cheng H, Yen K. Secrets of the lac operon. Glucose hysteresis as a mechanism in dietary restriction, aging and disease. INTERDISCIPLINARY TOPICS IN GERONTOLOGY 2006; 35:39-68. [PMID: 17063032 PMCID: PMC2755292 DOI: 10.1159/000096555] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Elevated blood glucose associated with diabetes produces progressive and apparently irreversible damage to many cell types. Conversely, reduction of glucose extends life span in yeast, and dietary restriction reduces blood glucose. Therefore it has been hypothesized that cumulative toxic effects of glucose drive at least some aspects of the aging process and, conversely, that protective effects of dietary restriction are mediated by a reduction in exposure to glucose. The mechanisms mediating cumulative toxic effects of glucose are suggested by two general principles of metabolic processes, illustrated by the lac operon but also observed with glucose-induced gene expression. First, metabolites induce the machinery of their own metabolism. Second, induction of gene expression by metabolites can entail a form of molecular memory called hysteresis. When applied to glucose-regulated gene expression, these two principles suggest a mechanism whereby repetitive exposure to postprandial excursions of glucose leads to an age-related increase in glycolytic capacity (and reduction in beta-oxidation of free fatty acids), which in turn leads to an increased generation of oxidative damage and a decreased capacity to respond to oxidative damage, independent of metabolic rate. According to this mechanism, dietary restriction increases life span and reduces pathology by reducing exposure to glucose and therefore delaying the development of glucose-induced glycolytic capacity.
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Affiliation(s)
- Charles V Mobbs
- Departments of Neuroscience and Geriatrics, Mount Sinai School of Medicine, 1 Gustave L. Levy Place, New York, NY 10029, USA.
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34
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Abstract
Iatrogenic hypoglycemia is a problem for people with diabetes. It causes recurrent morbidity, and sometimes death, as well as a vicious cycle of recurrent hypoglycemia, precluding maintenance of euglycemia over a lifetime of diabetes. Improved therapeutic approaches that will minimize both hypo- and hyperglycemia will be based on insight into the pathophysiology of glucoregulation, specifically glucose counterregulation, in insulin-deficient (type 1 and advanced type 2) diabetes. In such patients, hypoglycemia is the result of the interplay of relative or absolute therapeutic insulin excess and compromised physiological (the syndrome of defective glucose counterregulation) and behavioral (the syndrome of hypoglycemia unawareness) defenses against falling plasma glucose concentrations. The concept of hypoglycemia-associated autonomic failure (HAAF) in diabetes posits that recent antecedent iatrogenic hypoglycemia causes both defective glucose counterregulation (by reducing epinephrine responses to a given level of subsequent hypoglycemia in the setting of absent decrements in insulin and absent increments in glucagon) and hypoglycemia unawareness (by reducing sympathoadrenal and the resulting neurogenic symptom responses to a given level of subsequent hypoglycemia) and thus a vicious cycle of recurrent hypoglycemia. The clinical impact of HAAF is well established in type 1 diabetes; it also affects those with advanced type 2 diabetes. It is now known to be largely reversible, by as little as 2-3 weeks of scrupulous avoidance of hypoglycemia, in most affected patients. However, the mechanisms of HAAF and its component syndromes are largely unknown. Loss of the glucagon secretory response, a key feature of defective glucose counterregulation, is plausibly explained by insulin deficiency, specifically loss of the decrement in intraislet insulin that normally signals glucagon secretion as glucose levels fall. Reduced neurogenic symptoms, a key feature of hypoglycemia unawareness, are largely the result of reduced sympathetic neural responses to falling glucose levels. The mechanism by which hypoglycemia shifts the glycemic thresholds for sympathoadrenal activation to lower plasma glucose concentrations, the key feature of both components of HAAF, is not known. It does not appear to be the result of the release of a systemic mediator (e.g., cortisol, epinephrine) during antecedent hypoglycemia or of increased blood-to-brain glucose transport (although increased transport of alternative fuels is conceivable). It is likely the result of alterations of brain metabolism. Although there is an array of clues, the specific alteration remains to be identified. While the research focus has been largely on the hypothalamus, hypoglycemia is now known to activate widespread brain regions, including the medial prefrontal cortex. The possibility that HAAF could be the result of posthypoglycemic brain glycogen supercompensation has also been raised. Finally, there appear to be diverse causes of HAAF. In addition to recent antecedent hypoglycemia, these include exercise- and sleep-related HAAF. Clearly, a unifying mechanism of HAAF would need to incorporate these causes as well. Pending the prevention and cure of diabetes, critical fundamental, translational, and outcomes research is needed if we are to eliminate hypoglycemia from the lives of people affected by diabetes.
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Affiliation(s)
- Philip E Cryer
- Division of Endocrinology, Metabolism and Lipid Research and General Clinical Research Center, Campus Box 8127, Washington University School of Medicine, 660 South Euclid Ave., St. Louis, Missouri 63110, USA.
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