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Rieusset J. The role of endoplasmic reticulum-mitochondria contact sites in the control of glucose homeostasis: an update. Cell Death Dis 2018. [PMID: 29523782 PMCID: PMC5844895 DOI: 10.1038/s41419-018-0416-1] [Citation(s) in RCA: 149] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The contact sites that the endoplasmic reticulum (ER) forms with mitochondria, called mitochondria-associated membranes (MAMs), are a hot topic in biological research, and both their molecular determinants and their numerous roles in several signaling pathways are is continuously evolving. MAMs allow the exchange between both organelles of lipids, calcium (Ca2+), and likely reactive oxygen species, allowing adaptations of both cellular bioenergetics and cell fate depending of cellular needs or stresses. Therefore, it is not surprising that MAMs affect cellular metabolism. Nevertheless, recent arguments suggest that MAMs could also act as key hub of hormonal and/or nutrient signaling in several insulin-sensitive tissues, pointing a specific role of MAMs in the control of glucose homeostasis. Here, I provide a brief review and update on current key signaling roles of the MAMs in the control of glucose homeostasis in both health and metabolic diseases. Particularly, the relevance of ER-mitochondria miscommunication in the disruption of glucose homeostasis is analyzed in details in the liver, skeletal muscle, adipose tissue, and beta cells of the pancreas.
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Affiliation(s)
- Jennifer Rieusset
- Laboratoire CarMeN, Unité Mixte de Recherche INSERM U-1060 et INRA U-1397, Université Lyon 1, Oullins, 69600, France.
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Zhang L, Zhang YX, Qiu JN, Li J, Chen W, Guan YQ. Preparation and Characterization of Hypoglycemic Nanoparticles for Oral Insulin Delivery. Biomacromolecules 2017; 18:4281-4291. [DOI: 10.1021/acs.biomac.7b01322] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Li Zhang
- School
of Life Science, South China Normal University, Guangzhou 510631, China
| | - Yu-Xiao Zhang
- School
of Life Science, South China Normal University, Guangzhou 510631, China
| | - Jia-Ni Qiu
- School
of Life Science, South China Normal University, Guangzhou 510631, China
| | - Jian Li
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, China
| | - Wuya Chen
- School
of Life Science, South China Normal University, Guangzhou 510631, China
| | - Yan-Qing Guan
- School
of Life Science, South China Normal University, Guangzhou 510631, China
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, China
- Joint Laboratory of Laser Oncology with Cancer Center of Sun Yet-sen University, South China Normal University, Guangzhou 510631, China
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53
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Tanshinone I alleviates insulin resistance in type 2 diabetes mellitus rats through IRS-1 pathway. Biomed Pharmacother 2017. [DOI: 10.1016/j.biopha.2017.06.040] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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Hatem-Vaquero M, Griera M, García-Jerez A, Luengo A, Álvarez J, Rubio JA, Calleros L, Rodríguez-Puyol D, Rodríguez-Puyol M, De Frutos S. Peripheral insulin resistance in ILK-depleted mice by reduction of GLUT4 expression. J Endocrinol 2017; 234:115-128. [PMID: 28490443 DOI: 10.1530/joe-16-0662] [Citation(s) in RCA: 17] [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: 04/11/2017] [Accepted: 05/10/2017] [Indexed: 12/15/2022]
Abstract
The development of insulin resistance is characterized by the impairment of glucose uptake mediated by glucose transporter 4 (GLUT4). Extracellular matrix changes are induced when the metabolic dysregulation is sustained. The present work was devoted to analyze the possible link between the extracellular-to-intracellular mediator integrin-linked kinase (ILK) and the peripheral tissue modification that leads to glucose homeostasis impairment. Mice with general depletion of ILK in adulthood (cKD-ILK) maintained in a chow diet exhibited increased glycemia and insulinemia concurrently with a reduction of the expression and membrane presence of GLUT4 in the insulin-sensitive peripheral tissues compared with their wild-type littermates (WT). Tolerance tests and insulin sensitivity indexes confirmed the insulin resistance in cKD-ILK, suggesting a similar stage to prediabetes in humans. Under randomly fed conditions, no differences between cKD-ILK and WT were observed in the expression of insulin receptor (IR-B) and its substrate IRS-1 expressions. The IR-B isoform phosphorylated at tyrosines 1150/1151 was increased, but the AKT phosphorylation in serine 473 was reduced in cKD-ILK tissues. Similarly, ILK-blocked myotubes reduced their GLUT4 promoter activity and GLUT4 expression levels. On the other hand, the glucose uptake capacity in response to exogenous insulin was impaired when ILK was blocked in vivo and in vitro, although IR/IRS/AKT phosphorylation states were increased but not different between groups. We conclude that ILK depletion modifies the transcription of GLUT4, which results in reduced peripheral insulin sensitivity and glucose uptake, suggesting ILK as a molecular target and a prognostic biomarker of insulin resistance.
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Affiliation(s)
- Marco Hatem-Vaquero
- Department of Systems BiologyPhysiology Unit, Universidad de Alcalá, Madrid, Spain
- Instituto Reina Sofía de Investigación Renal and REDinREN from Instituto de Salud Carlos IIIMadrid, Spain
| | - Mercedes Griera
- Department of Systems BiologyPhysiology Unit, Universidad de Alcalá, Madrid, Spain
- Instituto Reina Sofía de Investigación Renal and REDinREN from Instituto de Salud Carlos IIIMadrid, Spain
| | - Andrea García-Jerez
- Department of Systems BiologyPhysiology Unit, Universidad de Alcalá, Madrid, Spain
- Instituto Reina Sofía de Investigación Renal and REDinREN from Instituto de Salud Carlos IIIMadrid, Spain
| | - Alicia Luengo
- Department of Systems BiologyPhysiology Unit, Universidad de Alcalá, Madrid, Spain
- Instituto Reina Sofía de Investigación Renal and REDinREN from Instituto de Salud Carlos IIIMadrid, Spain
| | - Julia Álvarez
- Endocrinology and Nutrition DepartmentHospital Príncipe de Asturias, Madrid, Spain
| | - José A Rubio
- Endocrinology and Nutrition DepartmentHospital Príncipe de Asturias, Madrid, Spain
| | - Laura Calleros
- Department of Systems BiologyPhysiology Unit, Universidad de Alcalá, Madrid, Spain
- Instituto Reina Sofía de Investigación Renal and REDinREN from Instituto de Salud Carlos IIIMadrid, Spain
| | - Diego Rodríguez-Puyol
- Instituto Reina Sofía de Investigación Renal and REDinREN from Instituto de Salud Carlos IIIMadrid, Spain
- Biomedical Research Foundation and Nephrology DepartmentHospital Príncipe de Asturias, Madrid, Spain
- Department of Systems BiologyPhysiology Unit, Universidad de Alcalá, Madrid, Spain
| | - Manuel Rodríguez-Puyol
- Department of Systems BiologyPhysiology Unit, Universidad de Alcalá, Madrid, Spain
- Instituto Reina Sofía de Investigación Renal and REDinREN from Instituto de Salud Carlos IIIMadrid, Spain
| | - Sergio De Frutos
- Department of Systems BiologyPhysiology Unit, Universidad de Alcalá, Madrid, Spain
- Instituto Reina Sofía de Investigación Renal and REDinREN from Instituto de Salud Carlos IIIMadrid, Spain
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Role of Endoplasmic Reticulum-Mitochondria Communication in Type 2 Diabetes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 997:171-186. [DOI: 10.1007/978-981-10-4567-7_13] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Pepe GJ, Maniu A, Aberdeen G, Lynch TJ, Kim SO, Nadler J, Albrecht ED. Insulin resistance elicited in postpubertal primate offspring deprived of estrogen in utero. Endocrine 2016; 54:788-797. [PMID: 27770396 PMCID: PMC6038696 DOI: 10.1007/s12020-016-1145-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 10/05/2016] [Indexed: 12/25/2022]
Abstract
We recently demonstrated that offspring delivered to baboons deprived of estrogen during the second half of gestation exhibited insulin resistance prior to onset of puberty. Because gonadal hormones have a profound effect on insulin action and secretion in adults, we determined whether insulin resistance is retained after initiation of gonadal secretion of testosterone and estradiol. Glucose tolerance tests were performed in postpubertal baboon offspring of untreated and letrozole-treated animals (serum estradiol reduced >95 %). Basal fasting levels of insulin (P < 0.05) and peak 1 min and 1 + 3 + 5 min levels of glucose after glucose tolerance tests challenge (P < 0.03) were greater in offspring delivered to letrozole-treated, estrogen-deprived baboons than untreated animals. Moreover, the value for the HOMA-IR, an accepted index of insulin resistance, was 2-fold greater (P < 0.05) in offspring delivered to baboons treated with letrozole than in untreated animals. Collectively these results support the proposal that estrogen normally has an important role in programming mechanisms in utero within the developing fetus that lead to insulin sensitivity after birth.
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Affiliation(s)
- Gerald J Pepe
- Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, VA, USA.
| | - Adina Maniu
- Department of Obstetrics/Gynecology/Reproductive Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Graham Aberdeen
- Department of Obstetrics/Gynecology/Reproductive Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Terrie J Lynch
- Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, VA, USA
| | - Soon Ok Kim
- Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, VA, USA
| | - Jerry Nadler
- Department of Internal Medicine, Eastern Virginia Medical School, Norfolk, VA, USA
| | - Eugene D Albrecht
- Departments of Obstetrics/Gynecology/Reproductive Sciences and Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
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Cai S, Sun W, Fan Y, Guo X, Xu G, Xu T, Hou Y, Zhao B, Feng X, Liu T. Effect of mulberry leaf (Folium Mori) on insulin resistance via IRS-1/PI3K/Glut-4 signalling pathway in type 2 diabetes mellitus rats. PHARMACEUTICAL BIOLOGY 2016; 54:2685-2691. [PMID: 27158744 DOI: 10.1080/13880209.2016.1178779] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
CONTEXT Folium Mori, the leaf of Morus alba L. (Moraceae), has been used in traditional Chinese medicine (TCM) for treating diabetes. However, it is unclear which components in the mulberry leaf are effective for the treatment of type 2 diabetes mellitus (T2DM). OBJECTIVE To investigate the flavonoids and polyphenols in mulberry leaves and their antihyperglycemic and antihyperlipidemic effects in T2DM rats. MATERIALS AND METHODS Male Sprague-Dawley rats were divided into five groups: normal control (NC), diabetic control (DBC), diabetic group with 0.3 mg/kg b.w./day rosiglitazone (RSG), diabetic group with 7 g/kg b.w./day TCM formula and diabetic group with 2 g/kg b.w./day Folium Mori extract (FME). After 4 weeks, the rats were sacrificed; biochemical parameters, gene and protein expression were measured. RESULTS The FBG level was significantly lower in the FME group than in the DBC group (p < 0.05). In oral glucose tolerance test, the AUC was significantly lower in the FME group (p < 0.05). The HOMA-IR level was significantly decreased in the FME group (p < 0.05). FME decreased the total cholesterol (TC), triglyceride (TG) and low density lipoprotein (LDL) levels (p < 0.05). FME increased the mRNA and protein expression of IRS-1, PI3K p85α and Glut-4 increased significantly (p < 0.05). Histological analysis revealed amelioration of lipid accumulation following FME treatment. Additionally, immunohistochemical analysis displayed stronger staining of Glut-4 in the FME group compared to the DBC group. DISCUSSION AND CONCLUSION FME could decrease the body weight, blood glucose, TG, TC and LDL levels, and improve insulin resistance. FME possessed significant antihyperglycemic and antihyperlipidemic activities via the IRS-1/PI3K/Glut-4 signalling pathway.
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Affiliation(s)
- Shengyu Cai
- a Beijing University of Chinese Medicine , Beijing , P.R. China
| | - Wen Sun
- b Key Laboratory of the Health-Cultivation of the Ministry of Education , Beijing University of Chinese Medicine , Beijing , P.R. China
- c Beijing Key Laboratory of the Health-Cultivation , Beijing , P.R. China
- d Beijing International Technology Cooperation Base for Prevention and Treatment of Diabetes Mellitus with Chinese Medicine , Beijing , P.R. China
| | - Yixin Fan
- e Department of Science and Technology , Beijing University of Chinese Medicine , Beijing , P.R. China
| | - Xuan Guo
- f Dongfang Hospital Affiliated to Beijing University of Chinese Medicine , Beijing , P.R. China
| | - Guangyuan Xu
- f Dongfang Hospital Affiliated to Beijing University of Chinese Medicine , Beijing , P.R. China
| | - Tunhai Xu
- g School of Chinese Pharmacy , Beijing University of Chinese Medicine , Beijing , P.R. China
| | - Yi Hou
- f Dongfang Hospital Affiliated to Beijing University of Chinese Medicine , Beijing , P.R. China
| | - Baosheng Zhao
- h Scientific Research Experiment Center, Beijing University of Chinese Medicine , Beijing , P.R. China
| | - Xingzhong Feng
- i Beijing Shijitan Hospital, Capital Medical University , Beijing , P.R. China
| | - Tonghua Liu
- b Key Laboratory of the Health-Cultivation of the Ministry of Education , Beijing University of Chinese Medicine , Beijing , P.R. China
- c Beijing Key Laboratory of the Health-Cultivation , Beijing , P.R. China
- d Beijing International Technology Cooperation Base for Prevention and Treatment of Diabetes Mellitus with Chinese Medicine , Beijing , P.R. China
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Cabrera D, Ruiz A, Cabello-Verrugio C, Brandan E, Estrada L, Pizarro M, Solis N, Torres J, Barrera F, Arrese M. Diet-Induced Nonalcoholic Fatty Liver Disease Is Associated with Sarcopenia and Decreased Serum Insulin-Like Growth Factor-1. Dig Dis Sci 2016; 61:3190-3198. [PMID: 27572941 DOI: 10.1007/s10620-016-4285-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 08/16/2016] [Indexed: 02/06/2023]
Abstract
BACKGROUND Decreased muscle mass or sarcopenia has been associated with nonalcoholic fatty liver disease (NAFLD). However, the functional consequences of this association and its pathogenesis remain ill-defined. AIMS To evaluate muscle mass and function in a diet-induced NAFLD mouse model and explore its association with changes in serum insulin-like growth factor-1 (IGF-1). METHODS Weight gain, visceral fat, serum biochemical parameters, liver histology, and hepatic triglyceride content (HTC) were assessed in C57/Bl6 mice fed a westernized diet during 16 weeks. In addition, we determined muscle fiber size and strength of limb skeletal muscle, myosin heavy chain (MHC) protein levels, and IGF-1 serum levels. RESULTS Westernized diet feeding was associated with weight gain, increased visceral fat mass (epididymal pad weight: 0.76 g ± 0.13 vs. 0.33 ± 0.27 g; p = 0.0023), hepatic steatosis (HTC: 118.2 ± 6.88 mg/g liver vs. 43.26 ± 5.63 mg/g<, p < 0.05), and necroinflammation (histological scores: 1.29 ± 0.42 vs. 4.00 ± 0.53<, p < 0.05). Also, mice fed the experimental diet had an increased proportion of low-diameter muscle fibers (0-30 μm) and a decreased proportion of high-diameter muscle fibers (60-90 μm), which correlated with decreased MHC protein levels, consistent with significant muscle atrophy. Functional studies showed that mice fed a westernized diet had reduced muscle strength and lower serum levels of IGF-1 (284.2 ± 20.04 pg/ml) compared with chow-fed mice (366.0 ± 12.42 pg/ml, p < 0.05). CONCLUSION Experimental NAFLD is associated with sarcopenia, decreased muscle strength, and reduced IGF-1 serum levels. IGF-1 reduction may be involved in pathogenesis of NAFLD-associated sarcopenia.
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Affiliation(s)
- Daniel Cabrera
- Departamento de Gastroenterología, Escuela de Medicina, Facultad de Medicina, Pontificia Universidad Católica de Chile, Marcoleta #367, 833-0024, Santiago, Chile.,Departamento de Ciencias Químicas y Biológicas, Facultad de salud, Universidad Bernardo O'Higgins, Santiago, Chile.,Centro de Regeneración y Envejecimiento (CARE), Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Alex Ruiz
- Instituto de Medicina, Facultad de Medicina, Universidad Austral de Chile, Valdivia, Chile
| | - Claudio Cabello-Verrugio
- Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas and Facultad de Medicina, Universidad Andres Bello, Santiago, Chile.,Millennium Institute on Immunology and Immunotherapy, Santiago, Chile
| | - Enrique Brandan
- Centro de Regeneración y Envejecimiento (CARE), Pontificia Universidad Católica de Chile, Santiago, Chile.,Laboratorio de Diferenciación Celular y Patología, Departamento de Biología Celular y Molecular, MIFAB, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Lisbell Estrada
- Departamento de Ciencias Químicas y Biológicas, Facultad de salud, Universidad Bernardo O'Higgins, Santiago, Chile
| | - Margarita Pizarro
- Departamento de Gastroenterología, Escuela de Medicina, Facultad de Medicina, Pontificia Universidad Católica de Chile, Marcoleta #367, 833-0024, Santiago, Chile
| | - Nancy Solis
- Departamento de Gastroenterología, Escuela de Medicina, Facultad de Medicina, Pontificia Universidad Católica de Chile, Marcoleta #367, 833-0024, Santiago, Chile
| | - Javiera Torres
- Departamento de Patología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Francisco Barrera
- Departamento de Gastroenterología, Escuela de Medicina, Facultad de Medicina, Pontificia Universidad Católica de Chile, Marcoleta #367, 833-0024, Santiago, Chile
| | - Marco Arrese
- Departamento de Gastroenterología, Escuela de Medicina, Facultad de Medicina, Pontificia Universidad Católica de Chile, Marcoleta #367, 833-0024, Santiago, Chile. .,Centro de Regeneración y Envejecimiento (CARE), Pontificia Universidad Católica de Chile, Santiago, Chile.
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Lower thigh muscle mass is associated with all-cause and cardiovascular mortality in elderly hemodialysis patients. Eur J Clin Nutr 2016; 71:64-69. [PMID: 27759066 DOI: 10.1038/ejcn.2016.186] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Revised: 08/23/2016] [Accepted: 08/25/2016] [Indexed: 12/16/2022]
Abstract
BACKGROUND/OBJECTIVES Higher body mass index appears protective in hemodialysis patients, although it remains to be determined which component of muscle or fat mass is primarily associated with this survival advantage. SUBJECTS/METHODS Eighty-one hemodialysis patients in our institution were prospectively followed from July 2011 to August 2015. Muscle and fat mass were evaluated by measuring the cross-sectional areas of the thigh and abdomen using computed tomography. The relationship between muscle and fat mass, and all-cause and cardiovascular mortality was studied using the Kaplan-Meier analyses and multivariate Cox proportional hazard models. RESULTS During more than 4 years of follow-up, 26 patients (32%) died. In the Kaplan-Meier curve analyses, lower thigh muscle mass was significantly associated with all-cause and cardiovascular mortality (log-rank test, P<0.01 and P<0.001, respectively), but there was no such association with thigh fat, abdominal muscle and fat mass levels. In multivariate Cox proportional hazard models, each 0.1 cm2/kg increase in the thigh muscle area adjusted by dry weight was associated with an estimated 22% lower risk of all-cause mortality (95% confidence interval (95% CI), 0.64-0.95, P<0.05) and a 30% lower risk of cardiovascular mortality (95% CI, 0.54-0.90, P<0.01). CONCLUSIONS Lower thigh muscle mass is significantly associated with all-cause and cardiovascular mortality in hemodialysis patients. Our findings indicate the importance of focusing on the muscle mass of lower extremities to predict the clinical outcomes of hemodialysis patients.
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Hormetic and regulatory effects of lipid peroxidation mediators in pancreatic beta cells. Mol Aspects Med 2016; 49:49-77. [PMID: 27012748 DOI: 10.1016/j.mam.2016.03.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2015] [Revised: 02/23/2016] [Accepted: 03/09/2016] [Indexed: 12/12/2022]
Abstract
Nutrient sensing mechanisms of carbohydrates, amino acids and lipids operate distinct pathways that are essential for the adaptation to varying metabolic conditions. The role of nutrient-induced biosynthesis of hormones is paramount for attaining metabolic homeostasis in the organism. Nutrient overload attenuate key metabolic cellular functions and interfere with hormonal-regulated inter- and intra-organ communication, which may ultimately lead to metabolic derangements. Hyperglycemia and high levels of saturated free fatty acids induce excessive production of oxygen free radicals in tissues and cells. This phenomenon, which is accentuated in both type-1 and type-2 diabetic patients, has been associated with the development of impaired glucose tolerance and the etiology of peripheral complications. However, low levels of the same free radicals also induce hormetic responses that protect cells against deleterious effects of the same radicals. Of interest is the role of hydroxyl radicals in initiating peroxidation of polyunsaturated fatty acids (PUFA) and generation of α,β-unsaturated reactive 4-hydroxyalkenals that avidly form covalent adducts with nucleophilic moieties in proteins, phospholipids and nucleic acids. Numerous studies have linked the lipid peroxidation product 4-hydroxy-2E-nonenal (4-HNE) to different pathological and cytotoxic processes. Similarly, two other members of the family, 4-hydroxyl-2E-hexenal (4-HHE) and 4-hydroxy-2E,6Z-dodecadienal (4-HDDE), have also been identified as potential cytotoxic agents. It has been suggested that 4-HNE-induced modifications in macromolecules in cells may alter their cellular functions and modify signaling properties. Yet, it has also been acknowledged that these bioactive aldehydes also function as signaling molecules that directly modify cell functions in a hormetic fashion to enable cells adapt to various stressful stimuli. Recent studies have shown that 4-HNE and 4-HDDE, which activate peroxisome proliferator-activated receptor δ (PPARδ) in vascular endothelial cells and insulin secreting beta cells, promote such adaptive responses to ameliorate detrimental effects of high glucose and diabetes-like conditions. In addition, due to the electrophilic nature of these reactive aldehydes they form covalent adducts with electronegative moieties in proteins, phosphatidylethanolamine and nucleotides. Normally these non-enzymatic modifications are maintained below the cytotoxic range due to efficient cellular neutralization processes of 4-hydroxyalkenals. The major neutralizing enzymes include fatty aldehyde dehydrogenase (FALDH), aldose reductase (AR) and alcohol dehydrogenase (ADH), which transform the aldehyde to the corresponding carboxylic acid or alcohols, respectively, or by biding to the thiol group in glutathione (GSH) by the action of glutathione-S-transferase (GST). This review describes the hormetic and cytotoxic roles of oxygen free radicals and 4-hydroxyalkenals in beta cells exposed to nutritional challenges and the cellular mechanisms they employ to maintain their level at functional range below the cytotoxic threshold.
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Paris M, Mourtzakis M. Assessment of skeletal muscle mass in critically ill patients: considerations for the utility of computed tomography imaging and ultrasonography. Curr Opin Clin Nutr Metab Care 2016; 19:125-30. [PMID: 26808266 DOI: 10.1097/mco.0000000000000259] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
PURPOSE OF REVIEW Low muscularity and skeletal muscle atrophy are commonly exhibited in critically ill patients and have major implications on patient outcomes. Typically, in the ICU, body composition is assessed through anthropometrics or bioelectrical impedance analysis, but these modalities cannot specifically quantify skeletal muscle; thus, we evaluate the merits and challenges of using computed tomography (CT) and ultrasonography to specifically measure skeletal muscle in the ICU. RECENT FINDINGS CT-based cut points have been used to identify critically ill patients with low muscle mass, and low muscularity associates with poor clinical outcomes and function. Ultrasonography is emerging as a useful tool to quantify skeletal muscle loss and degradation in architecture, as well as prospectively track changes in these parameters over time. Rates of muscle atrophy and changes in muscle architecture has been quantified by ultrasonography and associated with poor clinical outcomes, but identification of critically ill patients with low muscularity is still in its infancy. SUMMARY CT imaging and ultrasonography require additional comprehensive validations against accurate measures of whole body muscle mass. As these validations begin to emerge, there will be a need to translate this knowledge into a simple tool that clinicians can apply as part of routine care.
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Affiliation(s)
- Michael Paris
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
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Amylin-mediated control of glycemia, energy balance, and cognition. Physiol Behav 2016; 162:130-40. [PMID: 26922873 DOI: 10.1016/j.physbeh.2016.02.034] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 02/20/2016] [Accepted: 02/22/2016] [Indexed: 12/26/2022]
Abstract
Amylin, a peptide hormone produced in the pancreas and in the brain, has well-established physiological roles in glycemic regulation and energy balance control. It improves postprandial blood glucose levels by suppressing gastric emptying and glucagon secretion; these beneficial effects have led to the FDA-approved use of the amylin analog pramlintide in the treatment of diabetes mellitus. Amylin also acts centrally as a satiation signal, reducing food intake and body weight. The ability of amylin to promote negative energy balance, along with its unique capacity to cooperatively facilitate or enhance the intake- and body weight-suppressive effects of other neuroendocrine signals like leptin, have made amylin a leading target for the development of novel pharmacotherapies for the treatment of obesity. In addition to these more widely studied effects, a growing body of literature suggests that amylin may play a role in processes related to cognition, including the neurodegeneration and cognitive deficits associated with Alzheimer's disease (AD). Although the function of amylin in AD is still unclear, intriguing recent reports indicate that amylin may improve cognitive ability and reduce hallmarks of neurodegeneration in the brain. The frequent comorbidity of diabetes mellitus and obesity, as well as the increased risk for and occurrence of AD associated with these metabolic diseases, suggests that amylin-based pharmaceutical strategies may provide multiple therapeutic benefits. This review will discuss the known effects of amylin on glycemic regulation, energy balance control, and cognitive/motivational processes. Particular focus will be devoted to the current and/or potential future clinical use of amylin pharmacotherapies for the treatment of diseases in each of these realms.
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Carnagarin R, Dharmarajan AM, Dass CR. PEDF attenuates insulin-dependent molecular pathways of glucose homeostasis in skeletal myocytes. Mol Cell Endocrinol 2016; 422:115-124. [PMID: 26700654 DOI: 10.1016/j.mce.2015.12.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 12/07/2015] [Accepted: 12/08/2015] [Indexed: 12/12/2022]
Abstract
Pigment epithelium-derived factor (PEDF) is an anti-angiogenic serpin associated with insulin resistance in metabolic disorders such as diabetes, metabolic syndrome, obesity and polycystic ovarian syndrome. While the mechanism of PEDF induced-insulin resistance of metabolic disorders has been attributed to its inflammatory and lipolytic effects, little evidence exists to support a direct role of PEDF in mediating insulin resistance. Here, we seminally provide evidence that PEDF can inhibit insulin signal transduction governing glucose homeostasis from the receptor to the effector phosphorylation through Akt/PKB-dependent and -independent pathways in mouse and human skeletal muscle cell lines. PEDF attenuates the insulin-dependent molecular axes of glucose metabolism. Exposure of skeletal myocytes to PEDF attenuates insulin-dependent insulin receptor autophosphorylation, tyrosine phosphorylation of insulin receptor substrate 1, and dual loop phosphorylation-activation of Akt. PEDF significantly inhibits the downstream effector - glycogen synthase kinase (and thereby the glycogenic axis of insulin signalling). PEDF turned off both the molecular switches of GLUT4 translocation: IRS-Akt/PKB-AS160 mediated and IR-pCbl-dependent GLUT4 translocation (the molecular axis of glucose uptake). These findings implicate a direct effect of PEDF on multiple insulin-dependent molecular mechanisms of glucose homeostasis in skeletal muscle cells, thereby enabling it to contribute to peripheral insulin resistance at the cellular level.
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Affiliation(s)
- Revathy Carnagarin
- Curtin Biosciences Research Precinct, Bentley, 6102, Australia; School of Pharmacy, Curtin University, Bentley, 6102, Australia
| | - Arun M Dharmarajan
- Curtin Biosciences Research Precinct, Bentley, 6102, Australia; School of Biomedical Science, Curtin University, Bentley, 6102, Australia
| | - Crispin R Dass
- Curtin Biosciences Research Precinct, Bentley, 6102, Australia; School of Pharmacy, Curtin University, Bentley, 6102, Australia.
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