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Mahmoud MF, Tawfeek N, Ali N, Hasan RA, Sobeh M, El-Shazly AM. Salix babylonica L. mitigates pancreatic damage by regulating the Beclin-P62/SQSTM1 autophagy pathway in rats. JOURNAL OF ETHNOPHARMACOLOGY 2023; 313:116425. [PMID: 37031826 DOI: 10.1016/j.jep.2023.116425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 03/02/2023] [Accepted: 03/21/2023] [Indexed: 05/16/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Salix babylonica L. belongs to the genus Salix, family Salicaceae. It is traditionally used as an antipyretic, antirheumatic, antidiabetic and for the treatment of ulcers and parasite skin diseases. It also has a range of pharmacological effects, such as anti-inflammatory, anti-tumor, antioxidant, and antibacterial effects. However, there are no reports on the phytochemical profile and efficacy of its leaves extract to modulate dexamethasone induced pancreatic damage. AIM OF THE STUDY The present study was performed to annotate the phytoconstituents of Salix babylonica leaf extract and explore whether and how it could modulate dexamethasone-induced pancreatic damage and the role of oxidative stress and autophagy in mediating its protective effects. MATERIALS AND METHODS Wistar rats were used for this study. Salix babylonica in two dose levels (100 and 200 mg/kg) or metformin (50 mg/kg) was given by oral gavage concurrently with dexamethasone which was injected SC in a dose of 10 mg/kg for 4 consecutive days. RESULTS LC-MS analysis furnished 84 secondary metabolites belonging to phenolic acids, salicinoids, proanthocyanidins, flavonoids, cyclohexanediol glycosides, and hydroxy fatty acids. S. babylonica at both dose levels and metformin decreased the elevated pancreatic beclin while elevated the decreased pancreatic P62/SQSTM1 content compared to dexamethasone. These effects were associated with improved histopathological changes, glycemic and lipid parameters indicating that there might be a connection between autophagy and dexamethasone-induced pancreatic damage. Given that the level of GSH was negatively correlated with the levels of beclin and positively correlated with P62/SQSTM1, while both MDA and NO levels were positively correlated with beclin and negatively correlated with P62/SQSTM1, it seems that dexamethasone induced autophagy may be attributed to dexamethasone induced pancreatic oxidative stress. CONCLUSION Our results indicate that S. babylonica protects pancreatic tissues against dexamethasone-induced damage by decreasing oxidative stress and its associated autophagy. Our study reveals a new mechanism for dexamethasone effects on pancreas and shows the potential therapeutic role of S. babylonica in mitigating dexamethasone adverse effects on pancreas and establishes the groundwork for future clinical applications.
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Affiliation(s)
- Mona F Mahmoud
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Zagazig University, Zagazig, 44519, Egypt.
| | - Nora Tawfeek
- Department of Pharmacognosy, Faculty of Pharmacy, Zagazig University, Zagazig, 44519, Egypt
| | - Noura Ali
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Zagazig University, Zagazig, 44519, Egypt
| | - Rehab A Hasan
- Department of Histology, Faculty of Medicine for Girls, Al Azhar University, Cairo, Egypt
| | - Mansour Sobeh
- AgroBioSciences Program, College for Sustainable Agriculture and Environmental Science, Mohammed VI Polytechnic University, Ben Guerir, 43150, Morocco
| | - Assem M El-Shazly
- Department of Pharmacognosy, Faculty of Pharmacy, Zagazig University, Zagazig, 44519, Egypt; Faculty of Pharmacy, El Saleheya El Gadida University, El Saleheya El Gadida, 44813, Egypt
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Mohammadi-Motlagh HR, Sadeghalvad M, Yavari N, Primavera R, Soltani S, Chetty S, Ganguly A, Regmi S, Fløyel T, Kaur S, Mirza AH, Thakor AS, Pociot F, Yarani R. β Cell and Autophagy: What Do We Know? Biomolecules 2023; 13:biom13040649. [PMID: 37189396 DOI: 10.3390/biom13040649] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 03/27/2023] [Accepted: 03/30/2023] [Indexed: 05/17/2023] Open
Abstract
Pancreatic β cells are central to glycemic regulation through insulin production. Studies show autophagy as an essential process in β cell function and fate. Autophagy is a catabolic cellular process that regulates cell homeostasis by recycling surplus or damaged cell components. Impaired autophagy results in β cell loss of function and apoptosis and, as a result, diabetes initiation and progress. It has been shown that in response to endoplasmic reticulum stress, inflammation, and high metabolic demands, autophagy affects β cell function, insulin synthesis, and secretion. This review highlights recent evidence regarding how autophagy can affect β cells' fate in the pathogenesis of diabetes. Furthermore, we discuss the role of important intrinsic and extrinsic autophagy modulators, which can lead to β cell failure.
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Affiliation(s)
- Hamid-Reza Mohammadi-Motlagh
- Medical Biology Research Center, Health Technology Institute, Kermanshah University of Medical Sciences, Kermanshah 67155-1616, Iran
| | - Mona Sadeghalvad
- Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran 1416634793, Iran
| | - Niloofar Yavari
- Department of Cellular and Molecular Medicine, The Panum Institute, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Rosita Primavera
- Interventional Regenerative Innovation at Stanford (IRIS), Department of Radiology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Setareh Soltani
- Clinical Research Development Center, Taleghani and Imam Ali Hospital, Kermanshah University of Medical Sciences, Kermanshah 67145-1673, Iran
| | - Shashank Chetty
- Interventional Regenerative Innovation at Stanford (IRIS), Department of Radiology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Abantika Ganguly
- Interventional Regenerative Innovation at Stanford (IRIS), Department of Radiology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Shobha Regmi
- Interventional Regenerative Innovation at Stanford (IRIS), Department of Radiology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Tina Fløyel
- Translational Type 1 Diabetes Research, Department of Clinical Research, Steno Diabetes Center Copenhagen, 2730 Herlev, Denmark
| | - Simranjeet Kaur
- Translational Type 1 Diabetes Research, Department of Clinical Research, Steno Diabetes Center Copenhagen, 2730 Herlev, Denmark
| | - Aashiq H Mirza
- Translational Type 1 Diabetes Research, Department of Clinical Research, Steno Diabetes Center Copenhagen, 2730 Herlev, Denmark
- Department of Pharmacology, Weill Cornell Medicine, New York, NY 10065, USA
| | - Avnesh S Thakor
- Interventional Regenerative Innovation at Stanford (IRIS), Department of Radiology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Flemming Pociot
- Translational Type 1 Diabetes Research, Department of Clinical Research, Steno Diabetes Center Copenhagen, 2730 Herlev, Denmark
- Institute for Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Reza Yarani
- Interventional Regenerative Innovation at Stanford (IRIS), Department of Radiology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
- Translational Type 1 Diabetes Research, Department of Clinical Research, Steno Diabetes Center Copenhagen, 2730 Herlev, Denmark
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Garmpi A, Damaskos C, Garmpis N, Kaminiotis VV, Georgakopoulou VE, Spandidos DA, Papalexis P, Diamantis E, Patsouras A, Kyriakos G, Tarantinos K, Syllaios A, Marinos G, Kouraklis G, Dimitroulis D. Role of histone deacetylase inhibitors in diabetic cardiomyopathy in experimental models (Review). MEDICINE INTERNATIONAL 2022; 2:26. [PMID: 36699507 PMCID: PMC9829213 DOI: 10.3892/mi.2022.51] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 08/02/2022] [Indexed: 01/28/2023]
Abstract
In diabetes, metabolic dysregulation, caused by hyperglycemia, leads to both structural and functional changes in cardiomyocytes and subsequently leads to the development of cardiomyopathy. Histone deacetylases (HDAC) are enzymes that regulate gene transcription. Their actions have been examined in the development of multiple disorders, such as cardiovascular diseases and diabetes. The use of HDAC inhibitors (HDACIs), as potential therapeutic agents against disease progression has yielded promising results. The present review article reports preclinical trials identified in which HDACIs were administered to mice suffering from diabetic cardiomyopathy (DCM), and discusses the role and mechanisms of action of HDAC and HDACIs in DCM. A review of the literature was performed using the PubMed database, aiming to identify publications in the English language concerning the role of HDACIs in DCM. More specifically, key words, separately and in various combinations, such as HDACIs, HDAC, diabetes, cardiomyopathy, heart failure and ischemia/reperfusion injury, were used. Furthermore, the references from all the articles were cross-checked in order to include any other eligible studies. The full-text articles assessed for eligibility were eight, covering the period from 2015 to 2019; finally, all of them were included. The use of HDACIs exhibited encouraging results against DCM progression through various mechanisms, including the reduction of reactive oxygen species generation, inflammatory cytokine production and fibrosis, and an increase in autophagy and angiogenesis.
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Affiliation(s)
- Anna Garmpi
- First Department of Propedeutic Internal Medicine, Laiko General Hospital, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece
| | - Christos Damaskos
- Renal Transplantation Unit, Laiko General Hospital, 11527 Athens, Greece,N.S. Christeas Laboratory of Experimental Surgery and Surgical Research, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece
| | - Nikolaos Garmpis
- N.S. Christeas Laboratory of Experimental Surgery and Surgical Research, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece,Second Department of Propedeutic Surgery, Laiko General Hospital, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece
| | - Vaios-Vasileios Kaminiotis
- Cardiothoracic Department, Derriford Hospital, University Hospitals Plymouth, PL6 8DH Plymouth, United Kingdom
| | - Vasiliki Epameinondas Georgakopoulou
- Department of Infectious Diseases-COVID-19 Unit, Laiko General Hospital, 11527 Athens, Greece,Correspondence to: Dr Vasiliki Epameinondas Georgakopoulou, Department of Infectious Diseases-COVID-19 Unit, Laiko General Hospital, 17 Agiou Thoma Street, 11527 Athens, Greece
| | - Demetrios A. Spandidos
- Laboratory of Clinical Virology, School of Medicine, University of Crete, 71003 Heraklion, Greece
| | - Petros Papalexis
- Unit of Endocrinology, First Department of Internal Medicine, Laiko General Hospital, National and Kapodistrian University of Athens, 11527 Athens, Greece,Department of Biomedical Sciences, University of West Attica, 12243 Athens, Greece
| | - Evangelos Diamantis
- Endocrinology Unit, Academic Department of Internal Medicine, Agioi Anargyroi General Oncology Hospital, National and Kapodistrian University of Athens, 14564 Athens, Greece
| | | | - George Kyriakos
- Department of Endocrinology and Nutrition, General Hospital Santa Lucia, 30202 Cartagena, Spain
| | | | | | - Georgios Marinos
- Department of Hygiene, Epidemiology and Medical Statistics, 11527 Athens, Greece
| | - Gregory Kouraklis
- Department of Surgery, Evgenideio Hospital, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece
| | - Dimitrios Dimitroulis
- Second Department of Propedeutic Surgery, Laiko General Hospital, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece
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Singh S, Bansal A, Singh V, Chopra T, Poddar J. Flavonoids, alkaloids and terpenoids: a new hope for the treatment of diabetes mellitus. J Diabetes Metab Disord 2022; 21:941-950. [PMID: 35673446 PMCID: PMC9167359 DOI: 10.1007/s40200-021-00943-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 11/24/2021] [Indexed: 01/11/2023]
Abstract
Diabetes mellitus is a metabolic syndrome characterized by a hyperglycemic state and multi-organ failure. Millions of people worldwide are suffering from this deadly disease taking a hit on their pocket and mental health in the name of its treatment. Modern medical practices with new technological advancements and discoveries have made revolutionary changes in the treatment. But, unfortunately, Glucose-lowering drugs used have many accompanying effects such as chronic vascular disease, renal malfunction, liver disease and, many skin problems. These complications have made us think about alternative treatments for diabetes with minimum or no side effects. Nowadays, in addition to modern medicine, herbal treatment has been suggested to treat diabetes mellitus. These herbal medicines contain biological macromolecules such as flavonoids, Terpenoids, glycosides, and alkaloids, which show versatile anti-diabetic effects. These phytochemicals are generally considered safe, and naturally occurring compounds have a potential role in preventing or controlling diabetes mellitus. The underlying mechanism of their anti-diabetic effects includes improvement in insulin secretion, decrease in insulin resistance, enhanced liver glycogen synthesis, antioxidant and anti-inflammatory activities. In this review, we have focused on the mechanism of various phytochemicals targeting hyperglycemia and its underlying pathogenesis.
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Affiliation(s)
- Sukhpal Singh
- Department of Biochemistry and Central Research Cell, M.M. Institute of Medical Sciences and Research, University Research Fellow, Maharishi Markandeswar (Deemed to be University, Mullana, Ambala, 133207 India
| | - Abhishek Bansal
- Department of Biochemistry, Government Medical College, RAJOURI, Rajouri, Jammu and Kashmir 185135 India
| | - Vikramjeet Singh
- Kalpana Chawla Government Medical College, Karnal, Haryana India
| | - Tanya Chopra
- Department Of Biochemistry and Central Research Cell, M.M. Institute of Medical Sciences and Research, Maharishi Markandeshwar (Deemed to be University), Mullana, Ambala, 133207 India
| | - Jit Poddar
- Department of Microbiology, RG Kar Medical College & Hospital, Kolkata, West Bengal 700003 India
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Gouda K, AbdelHamid S, Mansour A, Omar N, El-Mesallamy H. Amelioration of Diabetic Nephropathy by Targeting Autophagy via Rapamycin or Fasting: Relation to Cell Apoptosis/Survival. Curr Issues Mol Biol 2021; 43:1698-1714. [PMID: 34698133 PMCID: PMC8928967 DOI: 10.3390/cimb43030120] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 10/08/2021] [Accepted: 10/09/2021] [Indexed: 12/25/2022] Open
Abstract
Autophagy has been demonstrated to have a beneficial effect on diabetic nephropathy (DN). Rapamycin, an inhibitor of mTOR, was shown to stimulate β-cell autophagy. However, its effects on preventing or ameliorating DN is unclear, and its effects are worth studying. As fasting is now an attractive protective strategy, we aim to compare its effect to rapamycin effects on pancreatic and renal cells. Twenty-eight adult male Wistar Albino rats were randomly divided into four groups, using streptozotocin (STZ) to induce diabetes mellitus (DM). Autophagy was induced by two ways; rapamycin or fasting. The extent of autophagy and apoptosis were investigated by measuring the level of LC3B and p53 proteins, respectively, in pancreatic and kidney tissues using Western blotting (WB) technique and imaging the renal cells under transmission electron microscope. The efflux transporter P-glycoprotein was quantified by WB as well. Rapamycin-induced autophagy occurred concurrently with apoptosis. On the other hand, fasting supported P-glycoprotein recovery and renal cell survival together with disabling β-cells apoptosis. In conclusion, this study provides a potential link between rapamycin or fasting for the cross-regulation of apoptosis and autophagy in the setting of cell stress as DN. Unlike rapamycin, fasting enhanced the active expression of ABCB1 efflux protein, providing insights on the potential ameliorative effects of fasting in DN that require further elucidation.
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Affiliation(s)
- Khaled Gouda
- Biochemistry Department, Faculty of Pharmacy, Modern University for Technology and Information, Cairo 12055, Egypt; (K.G.); (N.O.)
| | - Sherihan AbdelHamid
- Biochemistry Department, Faculty of Pharmacy, Ain-Shams University, Cairo 11566, Egypt;
| | - Ahmed Mansour
- Pharmacology and Toxicology Department, Faculty of Pharmacy, Al-Azhar University, Cairo 11651, Egypt;
| | - Nesreen Omar
- Biochemistry Department, Faculty of Pharmacy, Modern University for Technology and Information, Cairo 12055, Egypt; (K.G.); (N.O.)
| | - Hala El-Mesallamy
- Biochemistry Department, Faculty of Pharmacy, Ain-Shams University, Cairo 11566, Egypt;
- Dean of Faculty of Pharmacy, Sinai University, North Sinai 45518, Egypt
- Correspondence: ; Tel.: +20-106-1669-913
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6
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Gadallah SH, Ghanem HM, Abdel-Ghaffar A, Metwaly FG, Hanafy LK, Ahmed EK. 4-Phenylbutyric acid and rapamycin improved diabetic status in high fat diet/streptozotocin-induced type 2 diabetes through activation of autophagy. Arch Physiol Biochem 2021; 127:235-244. [PMID: 31215250 DOI: 10.1080/13813455.2019.1628069] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
An accumulating body of evidence supports the role of autophagy in the pathophysiology of T2DM. Also, abnormal endoplasmic reticulum (ER) stress response that has been implicated as a cause of insulin resistance (IR) could also be affected by the autophagic status in β-cells. The present study was designed to investigate whether autophagy is regulated in T2DM as well as to investigate the modulatory effect of the ER stress inhibitor 4-phenylbutyric acid (4-PBA) and the autophagy inducer rapamycin (Rapa) on the autophagic and diabetic status using type 2 diabetic animal model with IR. Treatment of diabetic rats with either 4-PBA or Rapa improved significantly the states of hyperglycaemia and dyslipidaemia, increased the antioxidant capacity, reduced the levels of lipid peroxidation and ER stress and increased the autophagic flux. The obtained improvements were attributed mainly to the induction of autophagy with subsequent regulation of ER stress-oxidative activation and prevention of β-cell apoptosis.
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Affiliation(s)
- Shaimaa H Gadallah
- Department of Biochemistry, Faculty of Science, Ain Shams University, Cairo, Egypt
| | - Hala M Ghanem
- Department of Biochemistry, Faculty of Science, Ain Shams University, Cairo, Egypt
| | - Amany Abdel-Ghaffar
- Department of Biochemistry and Pharmacology, Research Institute of Ophthalmology, Giza, Egypt
| | - Fatma G Metwaly
- Department of Histology, Research Institute of Ophthalmology, Giza, Egypt
| | - Laila K Hanafy
- Department of Histology, Research Institute of Ophthalmology, Giza, Egypt
| | - Emad K Ahmed
- Department of Biochemistry, Faculty of Science, Ain Shams University, Cairo, Egypt
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Abstract
Pancreatic islet beta cells (β-cells) synthesize and secrete insulin in response to rising glucose levels and thus are a prime target in both major forms of diabetes. Type 1 diabetes ensues due to autoimmune destruction of β-cells. On the other hand, the prevailing insulin resistance and hyperglycemia in type 2 diabetes (T2D) elicits a compensatory response from β-cells that involves increases in β-cell mass and function. However, the sustained metabolic stress results in β-cell failure, characterized by severe β-cell dysfunction and loss of β-cell mass. Dynamic changes to β-cell mass also occur during pancreatic development that involves extensive growth and morphogenesis. These orchestrated events are triggered by multiple signaling pathways, including those representing the transforming growth factor β (TGF-β) superfamily. TGF-β pathway ligands play important roles during endocrine pancreas development, β-cell proliferation, differentiation, and apoptosis. Furthermore, new findings are suggestive of TGF-β's role in regulation of adult β-cell mass and function. Collectively, these findings support the therapeutic utility of targeting TGF-β in diabetes. Summarizing the role of the various TGF-β pathway ligands in β-cell development, growth and function in normal physiology, and during diabetes pathogenesis is the topic of this mini-review.
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Affiliation(s)
- Ji-Hyun Lee
- Cell Growth and Metabolism Section, Diabetes, Endocrinology & Obesity Branch, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Clinical Research Center, Bethesda, MD, USA
| | - Ji-Hyeon Lee
- Cell Growth and Metabolism Section, Diabetes, Endocrinology & Obesity Branch, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Clinical Research Center, Bethesda, MD, USA
| | - Sushil G Rane
- Cell Growth and Metabolism Section, Diabetes, Endocrinology & Obesity Branch, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Clinical Research Center, Bethesda, MD, USA
- Correspondence: Sushil G. Rane, PhD, Cell Growth and Metabolism Section, Diabetes, Endocrinology and Obesity Branch, National Institutes of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Clinical Research Center, Building 10, CRC-West 5-5940, 10 Center Drive, Bethesda, MD 20892, USA.
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Xia Q, Wu X, Rong K, Zhou Z, Li X, Fei T, Yin X. Lysosomal autophagy promotes recovery in rats with acute knee injury through TFEB mediation. J Orthop Surg Res 2020; 15:66. [PMID: 32085781 PMCID: PMC7035773 DOI: 10.1186/s13018-020-1573-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 01/23/2020] [Indexed: 02/07/2023] Open
Abstract
Background To study the role of lysosomal decomposition and elimination of old bone matrix, as well as the mechanism of promoting chondrocyte growth and bone recovery through the perspective of TFEB-mediated lysosomal autophagy. Methods Rat models of acute knee injury were designed, and autophagy flow was detected by injection of autophagy inhibitors 3-methyladenine. Autophagy flow was detected by RFP-GFP-LC3 double fluorescence molecule. The expression of TFEB, DRAM, MAPLC3, and MITF were analyzed by Western blot, and the expression of genes NITF, Bcl2, and TYR in rat cartilage tissues were detected by RT-PCR. Results The number of autophagosomes was increasing in the auto group compared with the inhibitor-auto group and normal group. There was a significant difference of LC3 levels in the auto group and inhibitor-auto group compared with the normal control. The expression of TFEB, DRAM, MAPLC3, and MITF proteins by Western blot analysis were significantly increased in the auto group and decreased in the inhibitor-auto group. The expression of NITF, Bcl2, and TYR by RT-PCR determination were higher in the auto group and inhibitor-auto group than the normal group. Conclusions Autophagy can inhibit apoptosis, promote chondrocyte growth and bone regeneration, and restore knee joint injury of rats. The main mechanism is to promote the effect of TFEB-mediated lysosomal autophagy.
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Affiliation(s)
- Qingquan Xia
- Department of Orthopedic, Minhang Hospital, Fudan University, No.39 Xinling Road, Minhang District, Shanghai, 201100, China
| | - Xuhua Wu
- Department of Orthopedic, Minhang Hospital, Fudan University, No.39 Xinling Road, Minhang District, Shanghai, 201100, China
| | - Ke Rong
- Department of Orthopedic, Minhang Hospital, Fudan University, No.39 Xinling Road, Minhang District, Shanghai, 201100, China.
| | - Zhenyu Zhou
- Department of Orthopedic, Minhang Hospital, Fudan University, No.39 Xinling Road, Minhang District, Shanghai, 201100, China
| | - Xujun Li
- Department of Orthopedic, Minhang Hospital, Fudan University, No.39 Xinling Road, Minhang District, Shanghai, 201100, China
| | - Teng Fei
- Department of Orthopedic, Minhang Hospital, Fudan University, No.39 Xinling Road, Minhang District, Shanghai, 201100, China
| | - Xiaofan Yin
- Department of Orthopedic, Minhang Hospital, Fudan University, No.39 Xinling Road, Minhang District, Shanghai, 201100, China
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Melnik BC. Milk exosomal miRNAs: potential drivers of AMPK-to-mTORC1 switching in β-cell de-differentiation of type 2 diabetes mellitus. Nutr Metab (Lond) 2019; 16:85. [PMID: 31827573 PMCID: PMC6898964 DOI: 10.1186/s12986-019-0412-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 11/22/2019] [Indexed: 12/15/2022] Open
Abstract
Type 2 diabetes mellitus (T2DM) steadily increases in prevalence since the 1950's, the period of widespread distribution of refrigerated pasteurized cow's milk. Whereas breastfeeding protects against the development of T2DM in later life, accumulating epidemiological evidence underlines the role of cow's milk consumption in T2DM. Recent studies in rodent models demonstrate that during the breastfeeding period pancreatic β-cells are metabolically immature and preferentially proliferate by activation of mechanistic target of rapamycin complex 1 (mTORC1) and suppression of AMP-activated protein kinase (AMPK). Weaning determines a metabolic switch of β-cells from a proliferating, immature phenotype with low insulin secretion to a differentiated mature phenotype with glucose-stimulated insulin secretion, less proliferation, reduced mTORC1- but increased AMPK activity. Translational evidence presented in this perspective implies for the first time that termination of milk miRNA transfer is the driver of this metabolic switch. miRNA-148a is a key inhibitor of AMPK and phosphatase and tensin homolog, crucial suppressors of mTORC1. β-Cells of diabetic patients return to the postnatal phenotype with high mTORC1 and low AMPK activity, explained by continuous transfer of bovine milk miRNAs to the human milk consumer. Bovine milk miRNA-148a apparently promotes β-cell de-differentiation to the immature mTORC1-high/AMPK-low phenotype with functional impairments in insulin secretion, increased mTORC1-driven endoplasmic reticulum stress, reduced autophagy and early β-cell apoptosis. In contrast to pasteurized cow's milk, milk's miRNAs are inactivated by bacterial fermentation, boiling and ultra-heat treatment and are missing in current infant formula. Persistent milk miRNA signaling adds a new perspective to the pathogenesis of T2DM and explains the protective role of breastfeeding but the diabetogenic effect of continued milk miRNA signaling by persistent consumption of pasteurized cow's milk.
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Affiliation(s)
- Bodo C. Melnik
- Department of Dermatology, Environmental Medicine and Health Theory, University of Osnabrück, Am Finkenhügel 7A, D-49076 Osnabrück, Germany
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Ahamad J, Toufeeq I, Khan MA, Ameen MSM, Anwer ET, Uthirapathy S, Mir SR, Ahmad J. Oleuropein: A natural antioxidant molecule in the treatment of metabolic syndrome. Phytother Res 2019; 33:3112-3128. [DOI: 10.1002/ptr.6511] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Revised: 07/25/2019] [Accepted: 08/23/2019] [Indexed: 02/03/2023]
Affiliation(s)
- Javed Ahamad
- Faculty of PharmacyTishk International University Erbil Iraq
| | - Ibrahim Toufeeq
- Faculty of PharmacyTishk International University Erbil Iraq
| | - Mohammad Ahmed Khan
- Department of Pharmacology, School of Pharmaceutical Education and ResearchJamia Hamdard New Delhi India
| | | | - Esra T. Anwer
- Faculty of PharmacyTishk International University Erbil Iraq
| | | | - Showkat R. Mir
- Department of Pharmacognosy, School of Pharmaceutical Education and Research (Formerly Faculty of Pharmacy)Jamia Hamdard New Delhi India
| | - Javed Ahmad
- Department of Pharmaceutics, College of PharmacyNajran University Najran Kingdom of Saudi Arabia
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11
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Identification of Circular RNAs Regulating Islet β-Cell Autophagy in Type 2 Diabetes Mellitus. BIOMED RESEARCH INTERNATIONAL 2019; 2019:4128315. [PMID: 31815137 PMCID: PMC6878796 DOI: 10.1155/2019/4128315] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 08/30/2019] [Accepted: 09/29/2019] [Indexed: 12/13/2022]
Abstract
This study is to identify the circular RNA (circRNA) expression profile that is functionally related to pancreatic islet β-cell autophagy and their potential regulation mechanisms in type 2 diabetes mellitus (T2DM). T2DM rat model was constructed by administration of high-fat and high-sugar diet. β-cells were isolated from islets by flow cytometry. CircRNA expression profile in β-cells was detected by circRNA microarrays, and the differentially expressed circRNAs were identified and validated by qRT-PCR. MicroRNA (miRNA) target prediction software and multiple bioinformatic approaches were used to construct a map of circRNA-miRNA interactions for the differentially expressed circRNAs. A total of 825 differentially expressed circular transcripts were identified in T2DM rats compared with control rats, among which 388 were upregulated and 437 were downregulated. Ten circRNAs were identified to have significant differences by qRT-PCR. GO analysis enriched terms such as organelle membrane and protein binding and the top enriched pathways for the circRNAs included MAPK signaling pathway. The differentially expressed circRNAs might involve in MAPK signaling pathway, apoptosis, and Ras signaling pathway. We speculate that these circRNAs, especially rno_circRNA_008565, can regulate the autophagy of islet β-cells via interactions with miRNA. Dysregulation of several circRNAs may play a role in T2DM development, and rno_circRNA_008565 may be a potential regulator of β-cell autophagy.
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12
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Bagherniya M, Butler AE, Barreto GE, Sahebkar A. The effect of fasting or calorie restriction on autophagy induction: A review of the literature. Ageing Res Rev 2018; 47:183-197. [PMID: 30172870 DOI: 10.1016/j.arr.2018.08.004] [Citation(s) in RCA: 159] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 08/22/2018] [Accepted: 08/24/2018] [Indexed: 12/13/2022]
Abstract
Autophagy is a lysosomal degradation process and protective housekeeping mechanism to eliminate damaged organelles, long-lived misfolded proteins and invading pathogens. Autophagy functions to recycle building blocks and energy for cellular renovation and homeostasis, allowing cells to adapt to stress. Modulation of autophagy is a potential therapeutic target for a diverse range of diseases, including metabolic conditions, neurodegenerative diseases, cancers and infectious diseases. Traditionally, food deprivation and calorie restriction (CR) have been considered to slow aging and increase longevity. Since autophagy inhibition attenuates the anti-aging effects of CR, it has been proposed that autophagy plays a substantive role in CR-mediated longevity. Among several stress stimuli inducers of autophagy, fasting and CR are the most potent non-genetic autophagy stimulators, and lack the undesirable side effects associated with alternative interventions. Despite the importance of autophagy, the evidence connecting fasting or CR with autophagy promotion has not previously been reviewed. Therefore, our objective was to weigh the evidence relating the effect of CR or fasting on autophagy promotion. We conclude that both fasting and CR have a role in the upregulation of autophagy, the evidence overwhelmingly suggesting that autophagy is induced in a wide variety of tissues and organs in response to food deprivation.
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Affiliation(s)
- Mohammad Bagherniya
- Department of Nutrition, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Alexandra E Butler
- Diabetes Research Center, Qatar Biomedical Research Institute, Doha, Qatar
| | - George E Barreto
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá D.C., Colombia; Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Santiago, Chile
| | - Amirhossein Sahebkar
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran; Neurogenic Inflammation Research Center, Mashhad University of Medical Sciences, Mashhad, Iran; School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, 9177948564, Iran.
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13
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The Role of Mammalian Target of Rapamycin (mTOR) in Insulin Signaling. Nutrients 2017; 9:nu9111176. [PMID: 29077002 PMCID: PMC5707648 DOI: 10.3390/nu9111176] [Citation(s) in RCA: 180] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 10/23/2017] [Accepted: 10/24/2017] [Indexed: 12/15/2022] Open
Abstract
The mammalian target of rapamycin (mTOR) is a serine/threonine kinase that controls a wide spectrum of cellular processes, including cell growth, differentiation, and metabolism. mTOR forms two distinct multiprotein complexes known as mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2), which are characterized by the presence of raptor and rictor, respectively. mTOR controls insulin signaling by regulating several downstream components such as growth factor receptor-bound protein 10 (Grb10), insulin receptor substrate (IRS-1), F-box/WD repeat-containing protein 8 (Fbw8), and insulin like growth factor 1 receptor/insulin receptor (IGF-IR/IR). In addition, mTORC1 and mTORC2 regulate each other through a feedback loop to control cell growth. This review outlines the current understanding of mTOR regulation in insulin signaling in the context of whole body metabolism.
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Mathur A, Pandey VK, Kakkar P. PHLPP: a putative cellular target during insulin resistance and type 2 diabetes. J Endocrinol 2017; 233:R185-R198. [PMID: 28428363 DOI: 10.1530/joe-17-0081] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 04/20/2017] [Indexed: 12/29/2022]
Abstract
Progressive research in the past decade converges to the impact of PHLPP in regulating the cellular metabolism through PI3K/AKT inhibition. Aberrations in PKB/AKT signaling coordinates with impaired insulin secretion and insulin resistance, identified during T2D, obesity and cardiovascular disorders which brings in the relevance of PHLPPs in the metabolic paradigm. In this review, we discuss the impact of PHLPP isoforms in insulin signaling and its associated cellular events including mitochondrial dysfunction, DNA damage, autophagy and cell death. The article highlights the plausible molecular targets that share the role during insulin-resistant states, whose understanding can be extended into treatment responses to facilitate targeted drug discovery for T2D and allied metabolic syndromes.
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Affiliation(s)
- Alpana Mathur
- Herbal Research LaboratoryCSIR-Indian Institute of Toxicology Research, Lucknow, India
- Babu Banarasi Das UniversityBBD City, Lucknow, India
| | - Vivek Kumar Pandey
- Herbal Research LaboratoryCSIR-Indian Institute of Toxicology Research, Lucknow, India
- Academy of Scientific and Innovative ResearchCSIR-IITR, Lucknow, India
| | - Poonam Kakkar
- Herbal Research LaboratoryCSIR-Indian Institute of Toxicology Research, Lucknow, India
- Babu Banarasi Das UniversityBBD City, Lucknow, India
- Academy of Scientific and Innovative ResearchCSIR-IITR, Lucknow, India
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15
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Yang JS, Lu CC, Kuo SC, Hsu YM, Tsai SC, Chen SY, Chen YT, Lin YJ, Huang YC, Chen CJ, Lin WD, Liao WL, Lin WY, Liu YH, Sheu JC, Tsai FJ. Autophagy and its link to type II diabetes mellitus. Biomedicine (Taipei) 2017; 7:8. [PMID: 28612706 PMCID: PMC5479440 DOI: 10.1051/bmdcn/2017070201] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 05/02/2017] [Indexed: 02/06/2023] Open
Abstract
Autophagy, a double-edged sword for cell survival, is the research object on 2016 Nobel Prize in Physiology or Medicine. Autophagy is a molecular mechanism for maintaining cellular physiology and promoting survival. Defects in autophagy lead to the etiology of many diseases, including diabetes mellitus (DM), cancer, neurodegeneration, infection disease and aging. DM is a metabolic and chronic disorder and has a higher prevalence in the world as well as in Taiwan. The character of diabetes mellitus is hyperglycemia resulting from defects in insulin secretion, insulin action, or both. Type 2 diabetes mellitus (T2DM) is characterized by insulin resistance and failure of producing insulin on pancreatic beta cells. In T2DM, autophagy is not only providing nutrients to maintain cellular energy during fasting, but also removes damaged organelles, lipids and miss-folded proteins. In addition, autophagy plays an important role in pancreatic beta cell dysfunction and insulin resistance. In this review, we summarize the roles of autophagy in T2DM.
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Affiliation(s)
- Jai-Sing Yang
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Department of Medical Research, China Medical University Hospital, China Medical University Taichung
404 Taiwan
| | - Chi-Cheng Lu
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Department of Medical Research, China Medical University Hospital, China Medical University Taichung
404 Taiwan
| | - Sheng-Chu Kuo
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School of Pharmacy, China Medical University Taichung
404 Taiwan
| | - Yuan-Man Hsu
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Department of Biological Science and Technology, China Medical University Taichung
404 Taiwan
| | - Shih-Chang Tsai
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Department of Biological Science and Technology, China Medical University Taichung
404 Taiwan
| | - Shih-Yin Chen
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Genetics Center, Department of Medical Research, China Medical University Hospital Taichung
404 Taiwan
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School of Chinese Medicine, China Medical University Taichung
404 Taiwan
| | - Yng-Tay Chen
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Genetics Center, Department of Medical Research, China Medical University Hospital Taichung
404 Taiwan
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School of Chinese Medicine, China Medical University Taichung
404 Taiwan
| | - Ying-Ju Lin
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Genetics Center, Department of Medical Research, China Medical University Hospital Taichung
404 Taiwan
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School of Chinese Medicine, China Medical University Taichung
404 Taiwan
| | - Yu-Chuen Huang
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Genetics Center, Department of Medical Research, China Medical University Hospital Taichung
404 Taiwan
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School of Chinese Medicine, China Medical University Taichung
404 Taiwan
| | - Chao-Jung Chen
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Genetics Center, Department of Medical Research, China Medical University Hospital Taichung
404 Taiwan
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School of Chinese Medicine, China Medical University Taichung
404 Taiwan
| | - Wei-De Lin
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Genetics Center, Department of Medical Research, China Medical University Hospital Taichung
404 Taiwan
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School of Chinese Medicine, China Medical University Taichung
404 Taiwan
| | - Wen-Lin Liao
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Genetics Center, Department of Medical Research, China Medical University Hospital Taichung
404 Taiwan
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School of Chinese Medicine, China Medical University Taichung
404 Taiwan
| | - Wei-Yong Lin
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Genetics Center, Department of Medical Research, China Medical University Hospital Taichung
404 Taiwan
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School of Chinese Medicine, China Medical University Taichung
404 Taiwan
| | - Yu-Huei Liu
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Genetics Center, Department of Medical Research, China Medical University Hospital Taichung
404 Taiwan
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School of Chinese Medicine, China Medical University Taichung
404 Taiwan
| | - Jinn-Chyuan Sheu
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Institute of Biomedical Sciences, National Sun Yat-sen University Kaohsiung
804 Taiwan
| | - Fuu-Jen Tsai
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Genetics Center, Department of Medical Research, China Medical University Hospital Taichung
404 Taiwan
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School of Chinese Medicine, China Medical University Taichung
404 Taiwan
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Department of Medical Genetics, China Medical University Hospital, China Medical University Taichung
404 Taiwan
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16
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Hyperglycaemia induces metabolic dysfunction and glycogen accumulation in pancreatic β-cells. Nat Commun 2016; 7:13496. [PMID: 27882918 PMCID: PMC5123088 DOI: 10.1038/ncomms13496] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 10/07/2016] [Indexed: 12/25/2022] Open
Abstract
Insulin secretion from pancreatic β-cells is impaired in all forms of diabetes. The resultant hyperglycaemia has deleterious effects on many tissues, including β-cells. Here we show that chronic hyperglycaemia impairs glucose metabolism and alters expression of metabolic genes in pancreatic islets. In a mouse model of human neonatal diabetes, hyperglycaemia results in marked glycogen accumulation, and increased apoptosis in β-cells. Sulphonylurea therapy rapidly normalizes blood glucose levels, dissipates glycogen stores, increases autophagy and restores β-cell metabolism. Insulin therapy has the same effect but with slower kinetics. Similar changes are observed in mice expressing an activating glucokinase mutation, in in vitro models of hyperglycaemia, and in islets from type-2 diabetic patients. Altered β-cell metabolism may underlie both the progressive impairment of insulin secretion and reduced β-cell mass in diabetes. Diabetes is characterized by prolonged hyperglycaemia and tissue damage in pancreatic islets. Here, Brereton et al. show that chronic high glucose levels lead to glycogen accumulation in β-cells, associated with reduced autophagy, impaired metabolism, insulin granule depletion and apoptosis.
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17
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An Update on Inflamm-Aging: Mechanisms, Prevention, and Treatment. J Immunol Res 2016; 2016:8426874. [PMID: 27493973 PMCID: PMC4963991 DOI: 10.1155/2016/8426874] [Citation(s) in RCA: 292] [Impact Index Per Article: 36.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 05/16/2016] [Accepted: 06/14/2016] [Indexed: 01/08/2023] Open
Abstract
Inflamm-aging is a challenging and promising new branch of aging-related research fields that includes areas such as immunosenescence. Increasing evidence indicates that inflamm-aging is intensively associated with many aging diseases, such as Alzheimer's disease, atherosclerosis, heart disease, type II diabetes, and cancer. Mounting studies have focused on the role of inflamm-aging in disease progression and many advances have been made in the last decade. However, the underlying mechanisms by which inflamm-aging affects pathological changes and disease development are still unclear. Here, we review studies of inflamm-aging that explore the concept, pathological features, mechanisms, intervention, and the therapeutic strategies of inflamm-aging in disease progression.
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18
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Sun Q, Nie S, Wang L, Yang F, Meng Z, Xiao H, Xiang B, Li X, Fu X, Wang S. Factors that Affect Pancreatic Islet Cell Autophagy in Adult Rats: Evaluation of a Calorie-Restricted Diet and a High-Fat Diet. PLoS One 2016; 11:e0151104. [PMID: 26963814 PMCID: PMC4786268 DOI: 10.1371/journal.pone.0151104] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 02/22/2016] [Indexed: 02/05/2023] Open
Abstract
Aging may be a risk factor for type 2 diabetes in the elderly. Dietary intervention can affect glucose tolerance in adults, which may be due to body composition and islet cell autophagy. The aim of this study was to determine the effects of various dietary interventions on islet cell autophagy. Pancreatic tissue and blood samples were collected from Sprague Dawley rats (14–16 months old, n = 15 for each group) that received a normal diet (ND), a high-fat diet (HFD), or a calorie-restricted diet (CRD). The body weight (BW), visceral fat, serum lipid levels, fasting serum glucose, insulin levels, and β/α cell area were determined in 14-16-(0-w), 16-18-(8-w), and 18-20(16-w)-month-old rats. Pancreatic islet autophagy (LC3B and LAMP2), AP (Acid Phosphatase) and apoptosis (apoptosis index, AI (TUNEL assay) and cleaved caspase-3) were detected using immunohistochemistry, ELISA and western blot. At 16 weeks, the expressions of LC3B, LAMP2 and AP markedly increased in both the HFD (P<0.01) and CRD (P<0.05) groups; however, an increase in the AI (P<0.05), cleaved caspase-3 and Beclin1 expression and a decrease in the expressions of BCL2 and BCLXL (P<0.05) were observed in only the HFD group. FFA, triglyceride levels, HOMA-IR, insulin levels and glucagon levels were significantly increased in the HFD group but decreased in the CRD group at 16 weeks (P<0.05). The degree of islet cell autophagy was potentially regulated by the levels of FFA and islet cell insulin and glucagon, which may have been due to the effects of Beclin1/BCL2.
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Affiliation(s)
- Qianqian Sun
- The Center of Gerontology and Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan province, China
| | - Shuangshuang Nie
- The Center of Gerontology and Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan province, China
| | - Lingxiao Wang
- The Center of Gerontology and Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan province, China
| | - Fan Yang
- The Center of Gerontology and Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan province, China
| | - Zhangming Meng
- The Center of Gerontology and Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan province, China
| | - Hengyi Xiao
- Laboratory of Aging Research, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan province, China
| | - Bing Xiang
- The Department of Hematology, West China Hospital, Sichuan University, Chengdu, Sichuan province, China
| | - Xiujun Li
- The Department of Endocrinology and Metabolism, West China Hospital, Sichuan University, Chengdu, Sichuan province, China
| | - Xianghui Fu
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu, Sichuan province, China
| | - Shuang Wang
- The Center of Gerontology and Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan province, China
- * E-mail:
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19
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Abstract
Type 2 diabetes is a complex disease. It results from a failure of the body to maintain energy homoeostasis. Multicellular organisms have evolved complex strategies to preserve a relatively stable internal nutrient environment, despite fluctuations in external nutrient availability. This complex strategy involves the co-ordinated responses of multiple organs to promote storage or mobilization of energy sources according to the availability of nutrients and cellular bioenergetics needs. The endocrine pancreas plays a central role in these processes by secreting insulin and glucagon. When this co-ordinated effort fails, hyperglycaemia and hyperlipidaemia develops, characterizing a state of metabolic imbalance and ultimately overt diabetes. Although diabetes is most likely a collection of diseases, scientists are starting to identify genetic components and environmental triggers. Genome-wide association studies revealed that by and large, gene variants associated with type 2 diabetes are implicated in pancreatic β-cell function, suggesting that the β-cell may be the weakest link in the chain of events that results in diabetes. Thus, it is critical to understand how environmental cues affect the β-cell. Phosphoinositides are important 'decoders' of environmental cues. As such, these lipids have been implicated in cellular responses to a wide range of growth factors, hormones, stress agents, nutrients and metabolites. Here we will review some of the well-established and potential new roles for phosphoinositides in β-cell function/dysfunction and discuss how our knowledge of phosphoinositide signalling could aid in the identification of potential strategies for treating or preventing type 2 diabetes.
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Affiliation(s)
- Lucia E Rameh
- Department of Medicine, Boston University School of Medicine, 650 Albany Street, Boston, MA 02118, U.S.A.
| | - Jude T Deeney
- Department of Medicine, Boston University School of Medicine, 650 Albany Street, Boston, MA 02118, U.S.A
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20
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Tian C, Ouyang X, Lv Q, Zhang Y, Xie W. Cross-talks between microRNAs and mRNAs in pancreatic tissues of streptozotocin-induced type 1 diabetic mice. Biomed Rep 2015; 3:333-342. [PMID: 26137232 DOI: 10.3892/br.2015.426] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 02/02/2015] [Indexed: 12/14/2022] Open
Abstract
Network cross-talks between microRNAs (miRNAs) and mRNAs may be useful to elucidate the pathological mechanisms of pancreatic islet cells in diabetic individuals. The aim of the present study was to investigate the cross-talks between miRNAs and mRNAs in pancreatic tissues of streptozotocin-induced diabetic mice through microarray and bioinformatic methods. Based on the miRNA microarray, 64 upregulated and 72 downregulated miRNAs were observed in pancreatic tissues in diabetic mice compared to the normal controls. Based on the mRNA microarrray, 507 upregulated mRNAs and 570 downregulated mRNAs were identified in pancreatic tissues in diabetic mice compared to the normal controls. Notably, there were 246 binding points between upregulated miRNA and downregulated mRNAs; simultaneously, there were 583 binding points between downregulated miRNA and upregulated mRNAs. These changed mRNA may potentially involve the following signaling pathways: Insulin secretion, pancreatic secretion, mammalian target of rapamycin signaling pathway, forkhead box O signaling pathway and phosphatidylinositol 3-kinase-protein kinase B signaling. The fluctuating effects of miRNAs and matched mRNAs indicated that miRNAs may have wide cross-talks with mRNAs in pancreatic tissues of type 1 diabetic mice. The cross-talks may play important roles in contributing to impaired islet functions and the development of diabetes. However, further functional validation should be conducted in the future.
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Affiliation(s)
- Caiming Tian
- Department of Chemistry, Tsinghua University, Beijing 100084, P.R. China ; Shenzhen Key Laboratory of Health Science and Technology, Division of Life Science and Health, Graduate School at Shenzhen, Tsinghua University, Shenzhen, Guangdong 518055, P.R. China
| | - Xiaoxi Ouyang
- Department of Health Inspection and Quarantine, School of Public Health, Sun Yat-sen University, Guangzhou, Guangdong 510080, P.R. China
| | - Qing Lv
- Department of Chemistry, Tsinghua University, Beijing 100084, P.R. China ; School of Life Sciences, Tsinghua University, Beijing 100084, P.R. China
| | - Yaou Zhang
- Shenzhen Key Laboratory of Health Science and Technology, Division of Life Science and Health, Graduate School at Shenzhen, Tsinghua University, Shenzhen, Guangdong 518055, P.R. China
| | - Weidong Xie
- Shenzhen Key Laboratory of Health Science and Technology, Division of Life Science and Health, Graduate School at Shenzhen, Tsinghua University, Shenzhen, Guangdong 518055, P.R. China
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21
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Wang Z, York NW, Nichols CG, Remedi MS. Pancreatic β cell dedifferentiation in diabetes and redifferentiation following insulin therapy. Cell Metab 2014; 19:872-82. [PMID: 24746806 PMCID: PMC4067979 DOI: 10.1016/j.cmet.2014.03.010] [Citation(s) in RCA: 289] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 02/06/2014] [Accepted: 02/26/2014] [Indexed: 01/09/2023]
Abstract
Diabetes is characterized by "glucotoxic" loss of pancreatic β cell function and insulin content, but underlying mechanisms remain unclear. A mouse model of insulin-secretory deficiency induced by β cell inexcitability (K(ATP) gain of function) demonstrates development of diabetes and reiterates the features of human neonatal diabetes. In the diabetic state, β cells lose their mature identity and dedifferentiate to neurogenin3-positive and insulin-negative cells. Lineage-tracing experiments show that dedifferentiated cells can subsequently redifferentiate to mature neurogenin3-negative, insulin-positive β cells after lowering of blood glucose by insulin therapy. We demonstrate here that β cell dedifferentiation, rather than apoptosis, is the main mechanism of loss of insulin-positive cells, and redifferentiation accounts for restoration of insulin content and antidiabetic drug responsivity in these animals. These results may help explain gradual decrease in β cell mass in long-standing diabetes and recovery of β cell function and drug responsivity in type 2 diabetic patients following insulin therapy, and they suggest an approach to rescuing "exhausted" β cells in diabetes.
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Affiliation(s)
- Zhiyu Wang
- Department of Medicine, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA; Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA
| | - Nathaniel W York
- Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA
| | - Colin G Nichols
- Department of Cell Biology and Physiology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA; Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA
| | - Maria S Remedi
- Department of Cell Biology and Physiology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA; Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA.
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22
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Abstract
Autophagy plays a key role in maintaining pancreatic β-cell homeostasis. Deregulation of this process is associated with loss of β-cell mass and function, and it is likely to be involved in type 2 diabetes development and progression. Evidence that modulation of autophagy may be beneficial to preserve β-cell mass and function is beginning to accumulate although the complexity of this process, the intricate link between autophagy and apoptosis, and the fine balance between the protective and the disruptive role of autophagy make it very difficult to develop interventional strategies. This chapter provides an overview of the role of constitutive and adaptive autophagy in pancreatic β-cell and in the context of type 2 diabetes.
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Affiliation(s)
- Simona Mazza
- Queen Mary University of London, Barts and The London School of Medicine and Dentistry, Blizard Institute, Centre for Diabetes, Inositide Signalling Group, London, United Kingdom
| | - Tania Maffucci
- Queen Mary University of London, Barts and The London School of Medicine and Dentistry, Blizard Institute, Centre for Diabetes, Inositide Signalling Group, London, United Kingdom.
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23
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Liu Y, Shi S, Gu Z, Du Y, Liu M, Yan S, Gao J, Li J, Shao Y, Zhong W, Chen X, Li C. Impaired autophagic function in rat islets with aging. AGE (DORDRECHT, NETHERLANDS) 2013; 35:1531-1544. [PMID: 22843415 PMCID: PMC3776112 DOI: 10.1007/s11357-012-9456-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Accepted: 07/04/2012] [Indexed: 06/01/2023]
Abstract
Type 2 diabetes is characterized by a deficit in β-cell function and mass, and its incidence increases with age. Autophagy is a highly regulated intracellular process for degrading cytoplasmic components, particularly protein aggregates and damaged organelles. Impaired or deficient autophagy is believed to cause or contribute to aging and age-related disease. Autophagy may be necessary to maintain structure, mass, and function of pancreatic β-cells. In this study, we investigated the effects of age on β-cell function and autophagy in pancreatic islets of 4-month-old (young), 14-month-old (adult), and 24-month-old (old) male Wistar rats. We found that islet β-cell function decreased gradually with age. Protein expression of the autophagy markers LC3/Atg8 and Atg7 exhibited a marked decline in aged islets. The expression of Lamp-2, a good indicator of autophagic degradation rate, was significantly reduced in the islets of old rats, suggesting that autophagic degradation is decreased in the islets of aged rats. However, protein expression of beclin-1/Atg6, which plays an important role in the induction and formation of the pre-autophagosome structure by associating with a multimeric complex of autophagy regulatory proteins (Atg14, Vps34/class 3 PI3 kinase, and Vps15), was most prominent in the islets of adult rats, and was higher in 24-month-old islets than in 4-month-old islets. The levels of p62/SQSTM1 and polyubiquitin aggregates, representing the functions of autophagy and proteasomal degradation, were increased in aging islets. 8-Hydroxydeoxyguanosine, a marker of mitochondrial and nuclear DNA oxidative damage, exhibited strong immunostaining in old islets. Analysis by electron microscopy demonstrated swelling and disintegration of cristae in the mitochondria of aged islets. These results suggest that β-cell and autophagic function in islets decline simultaneously with increasing age in Wistar rats, and that impaired autophagy in the islets of older rats may cause accumulation of misfolded and aggregated proteins and reduce the removal of abnormal mitochondria in β-cells, leading to reduced β-cell function. Dysfunctional autophagy in islets during the aging process may be an important mechanism leading to the development of type 2 diabetes.
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Affiliation(s)
- Yu Liu
- />Department of Geriatric Endocrinology, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 China
| | - Suozhu Shi
- />Department of Nephrology, State Key Lab of Kidney Diseases, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 China
| | - Zhaoyan Gu
- />Department of Geriatric Endocrinology, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 China
| | - Yingzhen Du
- />Department of Geriatric Endocrinology, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 China
| | - Minyan Liu
- />Department of Geriatric Endocrinology, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 China
| | - Shuangtong Yan
- />Department of Geriatric Endocrinology, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 China
| | - Jianjun Gao
- />Department of Nephrology, State Key Lab of Kidney Diseases, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 China
| | - Jian Li
- />Department of Geriatric Endocrinology, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 China
| | - Yinghong Shao
- />Department of Geriatric Endocrinology, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 China
| | - Wenwen Zhong
- />Department of Geriatric Endocrinology, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 China
| | - Xiangmei Chen
- />Department of Nephrology, State Key Lab of Kidney Diseases, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 China
| | - Chunlin Li
- />Department of Geriatric Endocrinology, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853 China
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24
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Cerf ME. Beta cell dynamics: beta cell replenishment, beta cell compensation and diabetes. Endocrine 2013; 44:303-11. [PMID: 23483434 DOI: 10.1007/s12020-013-9917-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Accepted: 03/01/2013] [Indexed: 12/19/2022]
Abstract
Type 2 diabetes, characterized by persistent hyperglycemia, arises mostly from beta cell dysfunction and insulin resistance and remains a highly complex metabolic disease due to various stages in its pathogenesis. Glucose homeostasis is primarily regulated by insulin secretion from the beta cells in response to prevailing glycemia. Beta cell populations are dynamic as they respond to fluctuating insulin demand. Beta cell replenishment and death primarily regulate beta cell populations. Beta cells, pancreatic cells, and extra-pancreatic cells represent the three tiers for replenishing beta cells. In rodents, beta cell self-replenishment appears to be the dominant source for new beta cells supported by pancreatic cells (non-beta islet cells, acinar cells, and duct cells) and extra-pancreatic cells (liver, neural, and stem/progenitor cells). In humans, beta cell neogenesis from non-beta cells appears to be the dominant source of beta cell replenishment as limited beta cell self-replenishment occurs particularly in adulthood. Metabolic states of increased insulin demand trigger increased insulin synthesis and secretion from beta cells. Beta cells, therefore, adapt to support their physiology. Maintaining physiological beta cell populations is a strategy for targeting metabolic states of persistently increased insulin demand as in diabetes.
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Affiliation(s)
- Marlon E Cerf
- Diabetes Discovery Platform, South African Medical Research, PO Box 19070, Tygerberg, 7505, South Africa,
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Abstract
Over the past two decades, insulin resistance has been considered essential to the aetiology of type 2 diabetes mellitus (T2DM). However, insulin resistance does not lead to T2DM unless it is accompanied by pancreatic β-cell dysfunction, because healthy β cells can compensate for insulin resistance by increasing in number and functional output. Furthermore, β-cell mass is decreased in patients with diabetes mellitus, suggesting a primary role for β-cell dysfunction in the pathogenesis of T2DM. The dysfunction of β cells can develop through various mechanisms, including oxidative, endoplasmic reticulum or hypoxic stress, as well as via induction of cytokines; these processes lead to apoptosis, uncontrolled autophagy and failure to proliferate. Transdifferentiation between β cells and α cells occurs under certain pathological conditions, and emerging evidence suggests that β-cell dedifferentiation or transdifferentiation might account for the reduction in β-cell mass observed in patients with severe T2DM. FOXO1, a key transcription factor in insulin signalling, is implicated in these mechanisms. This Review discusses advances in our understanding of the contribution of FOXO1 signalling to the development of β-cell failure in T2DM.
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Affiliation(s)
- Tadahiro Kitamura
- Metabolic Signal Research Centre, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15, Showa-machi, Maebashi, Gunma 371-8512, Japan.
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Wu J, Wu JJ, Yang LJ, Wei LX, Zou DJ. Rosiglitazone protects against palmitate-induced pancreatic beta-cell death by activation of autophagy via 5'-AMP-activated protein kinase modulation. Endocrine 2013; 44:87-98. [PMID: 23109223 DOI: 10.1007/s12020-012-9826-5] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 10/19/2012] [Indexed: 01/20/2023]
Abstract
Promoting beta-cell survival is crucial for the prevention of beta-cell failure in diabetes. Thiazolidinediones, a widely used drug to improve insulin sensitivity in clinical practice, is found to have a protective effect on islet beta-cell. To date, the mechanism underlying the protective role of thiazolidinedione on beta-cell survival remain largely unknown. Activation of autophagy was detected by transmission electron microscopy, western blot, and GFP-LC3 transfection. Cell viability was examined by WST-8. Cell apoptosis was demonstrated by DAPI and Annexin V/PI staining. Colony formation assay was used to detect long-term cell viability. We demonstrated that rosiglitazone-treated beta-cells were more resistant to palmitate-induced apoptosis. The conversion of LC3-I to LC3-II and accumulated autophagosomes were found to be upregulated in rosiglitazone-treated cells. Inhibition of autophagy augmented palmitate-induced apoptosis with rosiglitazone treatment, suggesting that autophagy plays an important role in the survival function of rosiglitazone on beta-cells. Furthermore, we showed that rosiglitazone could induce AMP-activated protein kinase (AMPK) phosphorylation and reduce p70S6 kinase phosphorylation. Inhibition of AMPK impaired autophagy activation and enhanced palmitate-induced apoptosis during rosiglitazone treatment. These findings reveal that rosiglitazone-induced autophagy contributes to its protective function on beta-cells during palmitate treatment.
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Affiliation(s)
- Jie Wu
- Department of Endocrinology, Chang Hai Hospital, The Second Military Medical University, 168 Changhai Road, Shanghai, 200438, People's Republic of China
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Xu X, Kobayashi S, Chen K, Timm D, Volden P, Huang Y, Gulick J, Yue Z, Robbins J, Epstein PN, Liang Q. Diminished autophagy limits cardiac injury in mouse models of type 1 diabetes. J Biol Chem 2013; 288:18077-92. [PMID: 23658055 DOI: 10.1074/jbc.m113.474650] [Citation(s) in RCA: 190] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Cardiac autophagy is inhibited in type 1 diabetes. However, it remains unknown if the reduced autophagy contributes to the pathogenesis of diabetic cardiomyopathy. We addressed this question using mouse models with gain- and loss-of-autophagy. Autophagic flux was inhibited in diabetic hearts when measured at multiple time points after diabetes induction by streptozotocin as assessed by protein levels of microtubule-associated protein light chain 3 form 2 (LC3-II) or GFP-LC3 puncta in the absence and presence of the lysosome inhibitor bafilomycin A1. Autophagy in diabetic hearts was further reduced in beclin 1- or Atg16-deficient mice but was restored partially or completely by overexpression of beclin 1 to different levels. Surprisingly, diabetes-induced cardiac damage was substantially attenuated in beclin 1- and Atg16-deficient mice as shown by improved cardiac function as well as reduced levels of oxidative stress, interstitial fibrosis, and myocyte apoptosis. In contrast, diabetic cardiac damage was dose-dependently exacerbated by beclin 1 overexpression. The cardioprotective effects of autophagy deficiency were reproduced in OVE26 diabetic mice. These effects were associated with partially restored mitophagy and increased expression and mitochondrial localization of Rab9, an essential regulator of a non-canonical alternative autophagic pathway. Together, these findings demonstrate that the diminished autophagy is an adaptive response that limits cardiac dysfunction in type 1 diabetes, presumably through up-regulation of alternative autophagy and mitophagy.
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Affiliation(s)
- Xianmin Xu
- Cardiovascular Health Research Center, Sanford Research/University of South Dakota, Department of Internal Medicine, University of South Dakota Sanford School of Medicine, Sioux Falls, South Dakota 57104, USA
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Barker CJ, Berggren PO. New Horizons in Cellular Regulation by Inositol Polyphosphates: Insights from the Pancreaticβ-Cell. Pharmacol Rev 2013; 65:641-69. [DOI: 10.1124/pr.112.006775] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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29
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Abstract
Beta cell dysfunction and insulin resistance are inherently complex with their interrelation for triggering the pathogenesis of diabetes also somewhat undefined. Both pathogenic states induce hyperglycemia and therefore increase insulin demand. Beta cell dysfunction results from inadequate glucose sensing to stimulate insulin secretion therefore elevated glucose concentrations prevail. Persistently elevated glucose concentrations above the physiological range result in the manifestation of hyperglycemia. With systemic insulin resistance, insulin signaling within glucose recipient tissues is defective therefore hyperglycemia perseveres. Beta cell dysfunction supersedes insulin resistance in inducing diabetes. Both pathological states influence each other and presumably synergistically exacerbate diabetes. Preserving beta cell function and insulin signaling in beta cells and insulin signaling in the glucose recipient tissues will maintain glucose homeostasis.
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Affiliation(s)
- Marlon E. Cerf
- Diabetes Discovery Platform, South African Medical Research CouncilCape Town, South Africa
- *Correspondence: Marlon E. Cerf, Diabetes Discovery Platform, South African Medical Research Council, PO Box 19070, Tygerberg, Cape Town 7505, South Africa. e-mail:
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30
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Redox homeostasis in pancreatic β cells. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2012; 2012:932838. [PMID: 23304259 PMCID: PMC3532876 DOI: 10.1155/2012/932838] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Accepted: 10/30/2012] [Indexed: 12/20/2022]
Abstract
We reviewed mechanisms that determine reactive oxygen species (redox) homeostasis, redox information signaling and metabolic/regulatory function of autocrine insulin signaling in pancreatic β cells, and consequences of oxidative stress and dysregulation of redox/information signaling for their dysfunction. We emphasize the role of mitochondrion in β cell molecular physiology and pathology, including the antioxidant role of mitochondrial uncoupling protein UCP2. Since in pancreatic β cells pyruvate cannot be easily diverted towards lactate dehydrogenase for lactate formation, the respiration and oxidative phosphorylation intensity are governed by the availability of glucose, leading to a certain ATP/ADP ratio, whereas in other cell types, cell demand dictates respiration/metabolism rates. Moreover, we examine the possibility that type 2 diabetes mellitus might be considered as an inevitable result of progressive self-accelerating oxidative stress and concomitantly dysregulated information signaling in peripheral tissues as well as in pancreatic β cells. It is because the redox signaling is inherent to the insulin receptor signaling mechanism and its impairment leads to the oxidative and nitrosative stress. Also emerging concepts, admiting participation of redox signaling even in glucose sensing and insulin release in pancreatic β cells, fit in this view. For example, NADPH has been firmly established to be a modulator of glucose-stimulated insulin release.
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Talchai C, Xuan S, Lin HV, Sussel L, Accili D. Pancreatic β cell dedifferentiation as a mechanism of diabetic β cell failure. Cell 2012; 150:1223-34. [PMID: 22980982 DOI: 10.1016/j.cell.2012.07.029] [Citation(s) in RCA: 1023] [Impact Index Per Article: 85.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Revised: 03/20/2012] [Accepted: 07/06/2012] [Indexed: 12/12/2022]
Abstract
Diabetes is associated with β cell failure. But it remains unclear whether the latter results from reduced β cell number or function. FoxO1 integrates β cell proliferation with adaptive β cell function. We interrogated the contribution of these two processes to β cell dysfunction, using mice lacking FoxO1 in β cells. FoxO1 ablation caused hyperglycemia with reduced β cell mass following physiologic stress, such as multiparity and aging. Surprisingly, lineage-tracing experiments demonstrated that loss of β cell mass was due to β cell dedifferentiation, not death. Dedifferentiated β cells reverted to progenitor-like cells expressing Neurogenin3, Oct4, Nanog, and L-Myc. A subset of FoxO1-deficient β cells adopted the α cell fate, resulting in hyperglucagonemia. Strikingly, we identify the same sequence of events as a feature of different models of murine diabetes. We propose that dedifferentiation trumps endocrine cell death in the natural history of β cell failure and suggest that treatment of β cell dysfunction should restore differentiation, rather than promoting β cell replication.
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Affiliation(s)
- Chutima Talchai
- Department of Medicine, Columbia University, New York, NY 10032, USA
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32
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Xu X, Ren J. Unmasking the janus faces of autophagy in obesity-associated insulin resistance and cardiac dysfunction. Clin Exp Pharmacol Physiol 2012; 39:200-8. [PMID: 22053892 DOI: 10.1111/j.1440-1681.2011.05638.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Autophagy is an intracellular, lysosomal-dependent process involved in the turnover of long-lived proteins, damaged organelles and other subcellular structures. The autophagic process is known to play an essential role in the maintenance of cellular homeostasis. Results from recent studies also indicate an important role for the autophagic process in the pathogenesis of human diseases, including cancer, cardiovascular diseases, obesity, diabetes mellitus and ageing. Because of the pivotal role of autophagy in the regulation of adipogenesis, obesity and insulin sensitization, research efforts have focused on elucidating the role of autophagy in metabolic syndrome. Mammalian target of rapamycin (mTOR) is a key regulator of cell growth and is characterized by a complex signalling mechanism that affects protein synthesis and autophagy. Results from experimental and clinical studies reveal some interesting, but conflicting, findings regarding the mTOR signalling pathway and autophagy in adipocytes in metabolic syndrome. Although the pivotal role of autophagy in obesity and other metabolic diseases has been established, its involvement in obesity-induced cardiac dysfunction remains unknown, as do the upstream signalling regulators of autophagy. The present minireview discusses the molecular mechanisms of autophagy in the regulation of cardiac function in overweight and obesity. Further studies using appropriate models are needed to better unravel the complex intracellular mechanisms involved in the regulation of autophagy in obesity-induced cardiac dysfunction.
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Affiliation(s)
- Xihui Xu
- Center for Cardiovascular Research and Alternative Medicine, University of Wyoming College of Health Sciences, Laramie, WY, USA
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33
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Sunahara KKS, Martins JO. Alveolar macrophages in diabetes: friends or foes? J Leukoc Biol 2012; 91:871-6. [DOI: 10.1189/jlb.0911488] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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Kobayashi S, Xu X, Chen K, Liang Q. Suppression of autophagy is protective in high glucose-induced cardiomyocyte injury. Autophagy 2012; 8:577-92. [PMID: 22498478 DOI: 10.4161/auto.18980] [Citation(s) in RCA: 112] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Hyperglycemia is linked to increased heart failure among diabetic patients. However, the mechanisms that mediate hyperglycemia-induced cardiac damage remain poorly understood. Autophagy is a cellular degradation pathway that plays important roles in cellular homeostasis. Autophagic activity is altered in the diabetic heart, but its functional role has been unclear. In this study, we determined if mimicking hyperglycemia in cultured cardiomyocytes from neonatal rats and adult mice could affect autophagic activity and myocyte viability. High glucose (17 or 30 mM) reduced autophagic flux compared with normal glucose (5.5 mM) as indicated by the difference in protein levels of LC3-II (microtubule-associated protein 1 light chain 3 form II) or the changes of punctate fluorescence patterns of GFP-LC3 and mRFP-LC3 in the absence and presence of the lysosomal inhibitor bafilomycin A(1). Unexpectedly, the inhibited autophagy turned out to be an adaptive response that functioned to limit high glucose cardiotoxicity. Indeed, suppression of autophagy by 3-methyladenine or short hairpin RNA-mediated silencing of the Becn1 or Atg7 gene attenuated high glucose-induced cardiomyocyte death. Conversely, upregulation of autophagy with rapamycin or overexpression of Becn1 or Atg7 predisposed cardiomyocytes to high glucose toxicity. Mechanistically, the high glucose-induced inhibition of autophagy was mediated at least partly by increased mTOR signaling that likely inactivated ULK1 through phosphorylation at serine 467. Together, these findings demonstrate that high glucose inhibits autophagy, which is a beneficial adaptive response that protects cardiomyocytes against high glucose toxicity. Future studies are warranted to determine if autophagy plays a similar role in diabetic heart in vivo.
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Affiliation(s)
- Satoru Kobayashi
- Cardiovascular Health Research Center, Sanford Research/ University of South Dakota, Department of Internal Medicine, University of South Dakota Sanford School of Medicine, Sioux Falls, SD, USA
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Rezzani R, Stacchiotti A, Rodella LF. Morphological and biochemical studies on aging and autophagy. Ageing Res Rev 2012; 11:10-31. [PMID: 21939784 DOI: 10.1016/j.arr.2011.09.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Revised: 09/05/2011] [Accepted: 09/08/2011] [Indexed: 12/11/2022]
Abstract
To maintain health in the elderly is a crucial objective for modern medicine that involves both basic and clinical researches. Autophagy is a fundamental auto-cannibalizing process that preserves cellular homeostasis and, if altered, either by excess or defect, greatly changes cell fate and can result in incapacitating human diseases. Efficient autophagy may prolong lifespan, but unfortunately this process becomes less efficient with age. The present review is focused on the close relationship between autophagy and age-related disorders in different tissues/organs and in transgenic animal models. In particular, it comments on the up to date literature on mechanisms responsible for age-related impairment of autophagy. Moreover, before discussing about these mechanisms, it is necessary to describe the metabolic autophagic regulation of autophagy and the proteins involved in this process. At the end, these data would summarize the autophagic link with aging process, as important tools in the future biogerontology scenario.
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Yasunaga M, Oumi N, Osaki M, Kazuki Y, Nakanishi T, Oshimura M, Sato K. Establishment and characterization of a transgenic mouse model for in vivo imaging of Bmp4 expression in the pancreas. PLoS One 2011; 6:e24956. [PMID: 21949805 PMCID: PMC3174230 DOI: 10.1371/journal.pone.0024956] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Accepted: 08/25/2011] [Indexed: 12/17/2022] Open
Abstract
Type-2 diabetes results from the development of insulin resistance and a concomitant impairment of insulin secretion. Bone morphogenetic protein 4 (Bmp4)-Bmp receptor 1A signaling in β cells has recently been reported to be required for insulin production and secretion. In addition, Bmp4 blocks the differentiation and promotes the expansion of endocrine progenitor cells. Bmp4 therefore regulates the maintenance of homeostasis in the pancreas. In this study, we constructed a reporter plasmid carrying 7-kb enhancer and promoter region of the Bmp4 gene upstream of the firefly luciferase gene. We used this construct to produce transgenic mice by pro-nuclear microinjection, for subsequent in vivo monitoring of Bmp4 expression. The bioluminescent signal was detected mainly in the pancreas in three independent lines of transgenic mice. Furthermore, the bioluminescent signal was enhanced in association with the autophagy response to 24-h fasting. These results suggest that pancreatic expression of Bmp4 is involved in responding to the physiological environment, including through autophagy. These mouse models represent useful tools for toxicological screening, and for investigating the mechanisms responsible for pancreatic Bmp4 functions in vivo, with relevance to improving our understanding of pancreatic diseases.
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Affiliation(s)
- Mayu Yasunaga
- Division of Molecular Biology, School of Life Sciences, Faculty of Medicine, Tottori University, Yonago, Japan
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37
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Rieusset J. Mitochondria and endoplasmic reticulum: mitochondria-endoplasmic reticulum interplay in type 2 diabetes pathophysiology. Int J Biochem Cell Biol 2011; 43:1257-62. [PMID: 21605696 DOI: 10.1016/j.biocel.2011.05.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Revised: 04/24/2011] [Accepted: 05/07/2011] [Indexed: 01/06/2023]
Abstract
Mitochondria and endoplasmic reticulum (ER) are two important metabolic organelles for the maintenance of cellular homeostasis and their functional defects are suspected to participate to the aetiology of type 2 diabetes (T2D). Particularly, excessive lipid intake and/or ectopic lipid accumulation in tissues (referred as lipotoxicity) are involved in alterations of both organelles and are closely linked to peripheral insulin resistance and defective insulin secretion. Since, mitochondria and ER are physically and functionally interconnected, their respective alterations during T2D could be interrelated. However, the mechanisms that coordinate the interplay between mitochondrial dysfunction and ER stress, and its relevance in the control of glucose homeostasis are unknown. Among these mechanisms, we will discuss on the potential role of altered mitochondria/ER crosstalk in organelle dysfunctions and in T2D pathophysiology.
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Affiliation(s)
- Jennifer Rieusset
- INSERM U1060, CarMeN laboratory, Lyon 1 University, F-69921 Oullins, France.
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38
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Dinarello CA, Fossati G, Mascagni P. Histone deacetylase inhibitors for treating a spectrum of diseases not related to cancer. Mol Med 2011; 17:333-52. [PMID: 21556484 DOI: 10.2119/molmed.2011.00116] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Accepted: 05/04/2011] [Indexed: 01/04/2023] Open
Abstract
This issue of Molecular Medicine contains 14 original research reports and state-of-the-art reviews on histone deacetylase inhibitors (HDACi's), which are being studied in models of a broad range of diseases not related to the proapoptotic properties used to treat cancer. The spectrum of these diseases responsive to HDACi's is for the most part due to several antiinflammatory properties, often observed in vitro but importantly also in animal models. One unifying property is a reduction in cytokine production as well as inhibition of cytokine postreceptor signaling. Distinct from their use in cancer, the reduction in inflammation by HDACi's is consistently observed at low concentrations compared with the higher concentrations required for killing tumor cells. This characteristic makes HDACi's attractive candidates for treating chronic diseases, since low doses are well tolerated. For example, low oral doses of the HDACi givinostat have been used in children to reduce arthritis and are well tolerated. In addition to the antiinflammatory properties, HDACi's have shown promise in models of neurodegenerative disorders, and HDACi's also hold promise to drive HIV-1 out of latently infected cells. No one molecular mechanism accounts for the non-cancer-related properties of HDACi's, since there are 18 genes coding for histone deacetylases. Rather, there are mechanisms unique for the pathological process of specific cell types. In this overview, we summarize the preclinical data on HDACi's for therapy in a wide spectrum of diseases unrelated to the treatment of cancer. The data suggest the use of HDACi's in treating autoimmune as well as chronic inflammatory diseases.
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Affiliation(s)
- Charles A Dinarello
- Department of Medicine, Division of Infectious Diseases, University of Colorado Denver, Aurora, Colorado 80045, USA.
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