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Oliveira MAB, de Abreu ACOV, Constantino DB, Tonon AC, Díez-Noguera A, Amaral FG, Hidalgo MP. Taking biological rhythms into account: From study design to results reporting. Physiol Behav 2024; 273:114387. [PMID: 37884108 DOI: 10.1016/j.physbeh.2023.114387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 09/22/2023] [Accepted: 10/23/2023] [Indexed: 10/28/2023]
Abstract
Numerous physiological and behavioral processes in living organisms exhibit strong rhythmicity and are regulated within a 24-hour cycle. These include locomotor activity and sleep patterns, feeding-fasting cycles, hormone synthesis, body temperature, and even mood and cognitive abilities, all of which are segregated into different phases throughout the day. These processes are governed by the internal timing system, a hierarchical multi-oscillator structure conserved across all organisms, from bacteria to humans. Circadian rhythms have been seen across multiple taxonomic kingdoms. In mammals, a hierarchical internal timing system is comprised of so-called central and periphereal clocks. Although these rhythms are intrinsic, they are under environmental influences, such as seasonal temperature changes, photoperiod variations, and day-night cycles. Recognizing the existence of biological rhythms and their primary external influences is crucial when designing and reporting experiments. Neglecting these physiological variations may result in inconsistent findings and misinterpretations. Thus, here we propose to incorporate biological rhythms into all stages of human and animal research, including experiment design, analysis, and reporting of findings. We also provide a flowchart to support decision-making during the design process, considering biological rhythmicity, along with a checklist outlining key factors that should be considered and documented throughout the study. This comprehensive approach not only benefits the field of chronobiology but also holds value for various other research disciplines. The insights gained from this study have the potential to enhance the validity, reproducibility, and overall quality of scientific investigations, providing valuable guidance for planning, developing, and communicating scientific studies.
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Affiliation(s)
- Melissa Alves Braga Oliveira
- Laboratório de Cronobiologia e Sono do Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil; Graduate Program in Psychiatry and Behavioral Sciences, Faculty of Medicine, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Ana Carolina Odebrecht Vergne de Abreu
- Laboratório de Cronobiologia e Sono do Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | | | - André C Tonon
- Laboratório de Cronobiologia e Sono do Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil; Graduate Program in Psychiatry and Behavioral Sciences, Faculty of Medicine, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Antoni Díez-Noguera
- Department de Bioquimica i Fisiologia, Facultat de Farmàcia i Ciències de l'Alimentació, Universitat de Barcelona, Barcelona, Spain
| | | | - Maria Paz Hidalgo
- Laboratório de Cronobiologia e Sono do Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil; Graduate Program in Psychiatry and Behavioral Sciences, Faculty of Medicine, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil.
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2
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Li W, Feng X, Zhang H, Wang YX, Zeng Q, Liu C, Zhong VW, Wang D. Association of shift work with oxidative stress and alteration of fasting plasma glucose level in Chinese adults. Obesity (Silver Spring) 2023; 31:2505-2514. [PMID: 37724057 DOI: 10.1002/oby.23845] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 04/23/2023] [Accepted: 05/27/2023] [Indexed: 09/20/2023]
Abstract
OBJECTIVE This study aimed to assess the association of shift work with blood glucose and the mediating role of oxidative stress. METHODS Fasting plasma glucose (FPG) and urinary concentrations of oxidative stress biomarkers (8-hydroxy-2'-deoxyguanosine [8-OHdG], 4-hydroxy-2-nonenal-mercapturic acid, and 8-iso-prostaglandin F2α [8-isoPGF2α ]) were measured among 831 participants. RESULTS Positive dose-response relationships among shift work duration, FPG (ptrend < 0.001), and abnormal glucose regulation (AGR; ptrend = 0.035) were found. Compared with participants without shift work, three-shift work was associated with a higher level of FPG (percentage change: 6.49%, 95% CI: 4.21%-8.83%) and a higher prevalence of impaired fasting glucose (odds ratio: 1.886, 95% CI: 1.114-3.192) and AGR (odds ratio: 1.929, 95% CI: 1.197-3.111). A dose-response relationship was found between shift work duration and 8-OHdG (ptrend = 0.002) and 8-isoPGF2α (ptrend = 0.019). Urinary 8-OHdG and 8-isoPGF2α partially mediated the association between shift work duration and FPG levels and the prevalence of impaired fasting glucose and AGR, with mediating proportions ranging from 4.77% to 20.76%. CONCLUSIONS These findings suggest that shift work is positively associated with blood glucose, and the association is partially mediated by oxidative stress.
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Affiliation(s)
- Wenzhen Li
- Department of Social Medicine and Health Management, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China
| | - Xiaobing Feng
- Department of Occupational and Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Haozhe Zhang
- Department of Occupational and Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yi-Xin Wang
- Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Qiang Zeng
- Department of Occupational and Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chong Liu
- Department of Occupational and Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Victor W Zhong
- Department of Epidemiology and Biostatistics, School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Dongming Wang
- Department of Occupational and Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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3
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Obodo D, Outland EH, Hughey JJ. Sex Inclusion in Transcriptome Studies of Daily Rhythms. J Biol Rhythms 2023; 38:3-14. [PMID: 36419398 PMCID: PMC9903005 DOI: 10.1177/07487304221134160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Biomedical research on mammals has traditionally neglected females, raising the concern that some scientific findings may generalize poorly to half the population. Although this lack of sex inclusion has been broadly documented, its extent within circadian genomics remains undescribed. To address this gap, we examined sex inclusion practices in a comprehensive collection of publicly available transcriptome studies on daily rhythms. Among 148 studies having samples from mammals in vivo, we found strong underrepresentation of females across organisms and tissues. Overall, only 23 of 123 studies in mice, 0 of 10 studies in rats, and 9 of 15 studies in humans included samples from females. In addition, studies having samples from both sexes tended to have more samples from males than from females. These trends appear to have changed little over time, including since 2016, when the US National Institutes of Health began requiring investigators to consider sex as a biological variable. Our findings highlight an opportunity to dramatically improve representation of females in circadian research and to explore sex differences in daily rhythms at the genome level.
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Affiliation(s)
- Dora Obodo
- Department of Biomedical Informatics, Vanderbilt University Medical Center, Nashville, Tennessee,Program in Chemical and Physical Biology, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Elliot H. Outland
- Department of Biomedical Informatics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Jacob J. Hughey
- Department of Biomedical Informatics, Vanderbilt University Medical Center, Nashville, Tennessee,Program in Chemical and Physical Biology, Vanderbilt University School of Medicine, Nashville, Tennessee,Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee,Jacob J. Hughey, Department of Biomedical Informatics, Vanderbilt University Medical Center, 2525 West End Ave., Suite 1475, Nashville, TN 37232, USA; e-mail:
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Biancolin AD, Srikrishnaraj A, Jeong H, Martchenko A, Brubaker PL. The Cytoskeletal Transport Protein, Secretagogin, Is Essential for Diurnal Glucagon-like Peptide-1 Secretion in Mice. Endocrinology 2022; 163:6678475. [PMID: 36036556 DOI: 10.1210/endocr/bqac142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Indexed: 11/19/2022]
Abstract
The intestinal L-cell incretin, glucagon-like peptide-1 (GLP-1), exhibits a circadian pattern of secretion, thereby entraining diurnal insulin release. Secretagogin (Scgn), an actin-binding regulatory protein, is essential for the temporal peak of GLP-1 secretion in vitro. To interrogate the role of Scgn in diurnal GLP-1 secretion in vivo, peak and trough GLP-1 release were evaluated in knockout mice (Scgn-/-, Gcg-CreERT2/+; Scgnfl/fl and Vil-CreERT2/+; Scgnfl/fl), and RNA sequencing (RNA-Seq) was conducted in Scgn knockdown L-cells. All 3 knockout models demonstrated loss of the diurnal rhythm of GLP-1 secretion in response to oral glucose. Gcg-CreERT2/+; Scgnfl/fl mice also lost the normal pattern in glucagon secretion, while Scgn-/- and Vil-CreERT2/+; Scgnfl/fl animals demonstrated impaired diurnal secretion of the related incretin, glucose-dependent insulinotrophic polypeptide. RNA-Seq of mGLUTag L-cells showed decreased pathways regulating vesicle transport, transport and binding, and protein-protein interaction at synapse, as well as pathways related to proteasome-mediated degradation including chaperone-mediated protein complex assembly following Scgn knockdown. Scgn is therefore essential for diurnal L-cell GLP-1 secretion in vivo, likely mediated through effects on secretory granule dynamics.
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Affiliation(s)
| | - Arjuna Srikrishnaraj
- Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Hyerin Jeong
- Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Alexandre Martchenko
- Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Patricia Lee Brubaker
- Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
- Department of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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Martchenko A, Biancolin AD, Martchenko SE, Brubaker PL. Nobiletin ameliorates high fat-induced disruptions in rhythmic glucagon-like peptide-1 secretion. Sci Rep 2022; 12:7271. [PMID: 35508494 PMCID: PMC9068808 DOI: 10.1038/s41598-022-11223-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 04/20/2022] [Indexed: 02/06/2023] Open
Abstract
The incretin hormone glucagon-like peptide-1 (GLP-1) is secreted by the intestinal L cell in response to nutrient intake. However, GLP-1 secretion also follows a circadian rhythm which is disrupted by the saturated fatty acid palmitate in vitro and high-fat diet (HFD) feeding in vivo. The flavonoid nobiletin is a clock enhancer which improves metabolic homeostasis. Therefore, the aim of this study was to elucidate whether and how nobiletin mitigates the negative effects of palmitate and HFD-feeding on rhythmic GLP-1 release. Pre-treatment of murine GLUTag L cells with palmitate dampened the GLP-1 secretory response at the normal peak of secretion, while nobiletin co-treatment restored GLP-1 secretion and upregulated the ‘metabolic pathway’ transcriptome. Mice fed a HFD also lost their GLP-1 secretory rhythm in association with markedly increased GLP-1 levels and upregulation of L cell transcriptional pathways related to ‘sensing’ and ‘transducing’ cellular stimuli at the normal peak of GLP-1 release. Nobiletin co-administration reduced GLP-1 levels to more physiological levels and upregulated L cell ‘oxidative metabolism’ transcriptional pathways. Furthermore, nobiletin improved colonic microbial 16S rRNA gene diversity and reduced the levels of Proteobacteria in HFD-fed mice. Collectively, this study establishes that nobiletin improves the normal rhythm in GLP-1 secretion following fat-induced disruption.
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Affiliation(s)
- Alexandre Martchenko
- Department of Physiology, University of Toronto, Rm 3366 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Andrew D Biancolin
- Department of Physiology, University of Toronto, Rm 3366 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Sarah E Martchenko
- Department of Physiology, University of Toronto, Rm 3366 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Patricia L Brubaker
- Department of Physiology, University of Toronto, Rm 3366 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada. .,Department of Medicine, University of Toronto, Toronto, ON, Canada.
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Brown MR, Matveyenko AV. It's What and When You Eat: An Overview of Transcriptional and Epigenetic Responses to Dietary Perturbations in Pancreatic Islets. Front Endocrinol (Lausanne) 2022; 13:842603. [PMID: 35355560 PMCID: PMC8960041 DOI: 10.3389/fendo.2022.842603] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 02/07/2022] [Indexed: 01/07/2023] Open
Abstract
Our ever-changing modern environment is a significant contributor to the increased prevalence of many chronic diseases, and particularly, type 2 diabetes mellitus (T2DM). Although the modern era has ushered in numerous changes to our daily living conditions, changes in "what" and "when" we eat appear to disproportionately fuel the rise of T2DM. The pancreatic islet is a key biological controller of an organism's glucose homeostasis and thus plays an outsized role to coordinate the response to environmental factors to preserve euglycemia through a delicate balance of endocrine outputs. Both successful and failed adaptation to dynamic environmental stimuli has been postulated to occur due to changes in the transcriptional and epigenetic regulation of pathways associated with islet secretory function and survival. Therefore, in this review we examined and evaluated the current evidence elucidating the key epigenetic mechanisms and transcriptional programs underlying the islet's coordinated response to the interaction between the timing and the composition of dietary nutrients common to modern lifestyles. With the explosion of next generation sequencing, along with the development of novel informatic and -omic approaches, future work will continue to unravel the environmental-epigenetic relationship in islet biology with the goal of identifying transcriptional and epigenetic targets associated with islet perturbations in T2DM.
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Affiliation(s)
- Matthew R. Brown
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, MN, United States
| | - Aleksey V. Matveyenko
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, MN, United States
- Division of Endocrinology, Metabolism, Diabetes, and Nutrition, Department of Medicine, Mayo Clinic College of Medicine and Science, Rochester, MN, United States
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7
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Martchenko SE, Martchenko A, Biancolin AD, Waller A, Brubaker PL. L-cell Arntl is required for rhythmic glucagon-like peptide-1 secretion and maintenance of intestinal homeostasis. Mol Metab 2021; 54:101340. [PMID: 34520858 PMCID: PMC8489154 DOI: 10.1016/j.molmet.2021.101340] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 09/03/2021] [Accepted: 09/07/2021] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVE Recent studies using whole-body clock-disrupted animals identified a disruption in the circadian rhythm of the intestinal L-cell incretin hormone, glucagon-like peptide-1 (GLP-1). Although GLP-1 plays an essential role in metabolism through enhancement of both glucose-stimulated insulin secretion and satiety, recent evidence has also demonstrated its importance in regulating intestinal and microbial homeostasis. Therefore, using in vivo and in vitro models, this study assessed the role of the core circadian clock gene Arntl in the regulation of time-dependent GLP-1 secretion and its impact on the intestinal environment. METHODS Oral glucose tolerance tests were conducted at zeitgeber time 2 and 14 in control and inducible Gcg-Arntl knockout (KO) mice. Colonic intraepithelial lymphocytes were isolated, mucosal gene expression analysis was conducted, and 16S rRNA gene sequencing of colonic feces as well as analysis of microbial metabolites were performed. Time-dependent GLP-1 secretion and transcriptomic analysis were conducted in murine (m) GLUTag L-cells following siRNA-mediated knockdown of Arntl. RESULTS Gcg-Arntl KO mice displayed disrupted rhythmic release of GLP-1 associated with reduced secretion at the established peak time point. Analysis of the intestinal environment in KO mice revealed a decreased proportion of CD4+ intraepithelial lymphocytes in association with increased proinflammatory cytokine gene expression and increased colonic weight. Moreover, increased Actinobacteria within the colonic microbiome was found following L-cell Arntl disruption, as well as reductions in the microbial products, short chain fatty acids, and bile acids. Finally, siRNA-mediated knockdown of Arntl in mGLUTag L-cells resulted in both impaired time-dependent GLP-1 secretion and the disruption of pathways related to key cellular processes. CONCLUSIONS These data establish, for the first time, the essential role of Arntl in the intestinal L-cell in regulating time-dependent GLP-1 secretion. Furthermore, this study revealed the integral role of L-cell Arntl in mediating the intestinal environment, which ultimately may provide novel insight into the development of therapeutics for the treatment of intestinal and metabolic disorders.
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Affiliation(s)
| | | | | | - Alison Waller
- Department of Biological Sciences, Brock University, St. Catharines, ON, Canada
| | - Patricia L Brubaker
- Department of Physiology, University of Toronto, Canada; Department of Medicine, University of Toronto, Toronto, ON, Canada.
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Abstract
β-Cells in the islet of Langerhans have a central role in maintaining energy homeostasis. Understanding the physiology of β-cells and other islet cells requires a deep understanding of their structural and functional organization, their interaction with vessels and nerves, the layout of paracrine interactions, and the relationship between subcellular compartments and protein complexes inside each cell. These elements are not static; they are dynamic and exert their biological actions at different scales of time. Therefore, scientists must be able to investigate (and visualize) short- and long-lived events within the pancreas and β-cells. Current technological advances in microscopy are able to bridge multiple spatiotemporal scales in biology to reveal the complexity and heterogeneity of β-cell biology. Here, I briefly discuss the historical discoveries that leveraged microscopes to establish the basis of β-cell anatomy and structure, the current imaging platforms that allow the study of islet and β-cell biology at multiple scales of resolution, and their challenges and implications. Lastly, I outline how the remarkable longevity of structural elements at different scales in biology, from molecules to cells to multicellular structures, could represent a previously unrecognized organizational pattern in developing and adult β-cells and pancreas biology.
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Affiliation(s)
- Rafael Arrojo E Drigo
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
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9
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Martchenko A, Brubaker PL. Effects of Obesogenic Feeding and Free Fatty Acids on Circadian Secretion of Metabolic Hormones: Implications for the Development of Type 2 Diabetes. Cells 2021; 10:cells10092297. [PMID: 34571945 PMCID: PMC8466112 DOI: 10.3390/cells10092297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 08/27/2021] [Accepted: 08/30/2021] [Indexed: 11/19/2022] Open
Abstract
Circadian rhythms are 24-h internal biological rhythms within organisms that govern virtually all aspects of physiology. Interestingly, metabolic tissues have been found to express cell-autonomous clocks that govern their rhythmic activity throughout the day. Disruption of normal circadian rhythmicity, as induced by environmental factors such as shift work, significantly increases the risk for the development of metabolic diseases, including type 2 diabetes and obesity. More recently, obesogenic feeding and its fatty acid components have also been shown to be potent disruptors of normal circadian biology. Two key hormones that are released in response to nutrient intake are the anti-diabetic incretin hormone glucagon-like peptide-1, from intestinal L cells, and insulin secreted by pancreatic β cells, both of which are required for the maintenance of metabolic homeostasis. This review will focus on the circadian function of the L and β cells and how both obesogenic feeding and the saturated fatty acid, palmitate, affect their circadian clock and function. Following introduction of the core biological clock and the hierarchical organization of the mammalian circadian system, the circadian regulation of normal L and β cell function and the importance of GLP-1 and insulin in establishing metabolic control are discussed. The central focus of the review then considers the circadian-disrupting effects of obesogenic feeding and palmitate exposure in L and β cells, while providing insight into the potential causative role in the development of metabolic disease.
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Affiliation(s)
| | - Patricia Lee Brubaker
- Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada;
- Department of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
- Correspondence:
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10
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Abstract
Beta cell dysfunction is central to the development of type 2 diabetes (T2D). In T2D, environmental and genetic influences can manifest beta cell dysfunction in many ways, including impaired glucose-sensing and secretion coupling mechanisms, insufficient adaptative responses to stress, and aberrant beta cell loss through increased cell death and/or beta cell de-differentiation. In recent years, circadian disruption has emerged as an important environmental risk factor for T2D. In support of this, genetic disruption of the circadian timing system in rodents impairs insulin secretion and triggers diabetes development, lending important evidence that the circadian timing system is intimately connected to, and essential for the regulation of pancreatic beta cell function; however, the role of the circadian timing system in the regulation of beta cell biology is only beginning to be unraveled. Here, we review the recent literature that explores the importance of the pancreatic islet/beta cell circadian clock in the regulation of various aspects of beta cell biology, including transcriptional and functional control of daily cycles of insulin secretion capacity, regulation of postnatal beta cell maturation, and control of the adaptive responses of the beta cell to metabolic stress and acute injury.
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Affiliation(s)
- Nivedita Seshadri
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, Manitoba R3E 0J9, Canada
- Children’s Hospital Research Institute of Manitoba, Winnipeg, Manitoba R3E 3P4, Canada
| | - Christine A Doucette
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, Manitoba R3E 0J9, Canada
- Children’s Hospital Research Institute of Manitoba, Winnipeg, Manitoba R3E 3P4, Canada
- Correspondence: Christine A. Doucette, PhD, University of Manitoba, Department of Physiology and Pathophysiology, Children’s Hospital Research Institute of Manitoba, John Buhler Research Centre 603, 715 McDermot Ave, Winnipeg, Manitoba, R3E 3P4, Canada.
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11
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Javeed N, Her TK, Brown MR, Vanderboom P, Rakshit K, Egan AM, Vella A, Lanza I, Matveyenko AV. Pro-inflammatory β cell small extracellular vesicles induce β cell failure through activation of the CXCL10/CXCR3 axis in diabetes. Cell Rep 2021; 36:109613. [PMID: 34433033 PMCID: PMC8420815 DOI: 10.1016/j.celrep.2021.109613] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 06/04/2021] [Accepted: 08/05/2021] [Indexed: 12/13/2022] Open
Abstract
Coordinated communication among pancreatic islet cells is necessary for maintenance of glucose homeostasis. In diabetes, chronic exposure to pro-inflammatory cytokines has been shown to perturb β cell communication and function. Compelling evidence has implicated extracellular vesicles (EVs) in modulating physiological and pathological responses to β cell stress. We report that pro-inflammatory β cell small EVs (cytokine-exposed EVs [cytoEVs]) induce β cell dysfunction, promote a pro-inflammatory islet transcriptome, and enhance recruitment of CD8+ T cells and macrophages. Proteomic analysis of cytoEVs shows enrichment of the chemokine CXCL10, with surface topological analysis depicting CXCL10 as membrane bound on cytoEVs to facilitate direct binding to CXCR3 receptors on the surface of β cells. CXCR3 receptor inhibition reduced CXCL10-cytoEV binding and attenuated β cell dysfunction, inflammatory gene expression, and leukocyte recruitment to islets. This work implies a significant role of pro-inflammatory β cell-derived small EVs in modulating β cell function, global gene expression, and antigen presentation through activation of the CXCL10/CXCR3 axis.
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Affiliation(s)
- Naureen Javeed
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA.
| | - Tracy K Her
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA
| | - Matthew R Brown
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA
| | - Patrick Vanderboom
- Division of Endocrinology, Diabetes, and Metabolism, Mayo Clinic, Rochester, MN 55905, USA
| | - Kuntol Rakshit
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA
| | - Aoife M Egan
- Division of Endocrinology, Diabetes, and Metabolism, Mayo Clinic, Rochester, MN 55905, USA
| | - Adrian Vella
- Division of Endocrinology, Diabetes, and Metabolism, Mayo Clinic, Rochester, MN 55905, USA
| | - Ian Lanza
- Division of Endocrinology, Diabetes, and Metabolism, Mayo Clinic, Rochester, MN 55905, USA
| | - Aleksey V Matveyenko
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA; Division of Endocrinology, Diabetes, and Metabolism, Mayo Clinic, Rochester, MN 55905, USA
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Beam CA, Beli E, Wasserfall CH, Woerner SE, Legge MT, Evans-Molina C, McGrail KM, Silk R, Grant MB, Atkinson MA, DiMeglio LA. Peripheral immune circadian variation, synchronisation and possible dysrhythmia in established type 1 diabetes. Diabetologia 2021; 64:1822-1833. [PMID: 34003304 PMCID: PMC8245361 DOI: 10.1007/s00125-021-05468-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 02/10/2021] [Indexed: 12/30/2022]
Abstract
AIMS/HYPOTHESIS The circadian clock influences both diabetes and immunity. Our goal in this study was to characterise more thoroughly the circadian patterns of immune cell populations and cytokines that are particularly relevant to the immune pathology of type 1 diabetes and thus fill in a current gap in our understanding of this disease. METHODS Ten individuals with established type 1 diabetes (mean disease duration 11 years, age 18-40 years, six female) participated in a circadian sampling protocol, each providing six blood samples over a 24 h period. RESULTS Daily ranges of population frequencies were sometimes large and possibly clinically significant. Several immune populations, such as dendritic cells, CD4 and CD8 T cells and their effector memory subpopulations, CD4 regulatory T cells, B cells and cytokine IL-6, exhibited statistically significant circadian rhythmicity. In a comparison with historical healthy control individuals, but using shipped samples, we observed that participants with type 1 diabetes had statistically significant phase shifts occurring in the time of peak occurrence of B cells (+4.8 h), CD4 and CD8 T cells (~ +5 h) and their naive and effector memory subsets (~ +3.3 to +4.5 h), and regulatory T cells (+4.1 h). An independent streptozotocin murine experiment confirmed the phase shifting of CD8 T cells and suggests that circadian dysrhythmia in type 1 diabetes might be an effect and not a cause of the disease. CONCLUSIONS/INTERPRETATION Future efforts investigating this newly described aspect of type 1 diabetes in human participants are warranted. Peripheral immune populations should be measured near the same time of day in order to reduce circadian-related variation.
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Affiliation(s)
- Craig A Beam
- Department of Biomedical Sciences, Homer Stryker MD School of Medicine, Western Michigan University, Kalamazoo, MI, USA.
| | - Eleni Beli
- Wellcome Wolfson Institute for Experimental Medicine, Queens University Belfast, Belfast, NI, UK.
- Indiana University Center for Diabetes and Metabolic Diseases, Indianapolis, IN, USA.
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, USA.
| | - Clive H Wasserfall
- Department of Pathology, Immunology and Laboratory Medicine, University of Florida, Gainesville, FL, USA
- University of Florida Diabetes Institute, Gainesville, FL, USA
| | - Stephanie E Woerner
- Indiana University Center for Diabetes and Metabolic Diseases, Indianapolis, IN, USA
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Megan T Legge
- Indiana University Center for Diabetes and Metabolic Diseases, Indianapolis, IN, USA
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Carmella Evans-Molina
- Indiana University Center for Diabetes and Metabolic Diseases, Indianapolis, IN, USA
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, USA
- Richard L. Roudebush VA Medical Center, Indianapolis, IN, USA
| | - Kieran M McGrail
- Department of Pathology, Immunology and Laboratory Medicine, University of Florida, Gainesville, FL, USA
- University of Florida Diabetes Institute, Gainesville, FL, USA
| | - Ryan Silk
- Wellcome Wolfson Institute for Experimental Medicine, Queens University Belfast, Belfast, NI, UK
| | - Maria B Grant
- Department of Ophthalmology, University of Alabama, Birmingham, AL, USA
| | - Mark A Atkinson
- Department of Pathology, Immunology and Laboratory Medicine, University of Florida, Gainesville, FL, USA
- University of Florida Diabetes Institute, Gainesville, FL, USA
| | - Linda A DiMeglio
- Indiana University Center for Diabetes and Metabolic Diseases, Indianapolis, IN, USA
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, USA
- Richard L. Roudebush VA Medical Center, Indianapolis, IN, USA
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13
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Schwartz PB, Walcheck MT, Berres M, Nukaya M, Wu G, Carrillo ND, Matkowskyj KA, Ronnekleiv-Kelly SM. Chronic jetlag-induced alterations in pancreatic diurnal gene expression. Physiol Genomics 2021; 53:319-335. [PMID: 34056925 PMCID: PMC8409905 DOI: 10.1152/physiolgenomics.00022.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 05/17/2021] [Accepted: 05/20/2021] [Indexed: 12/13/2022] Open
Abstract
Cell-autonomous circadian clocks exist in nearly every organ and function to maintain homeostasis through a complex series of transcriptional-translational feedback loops. The response of these peripheral clocks to external perturbations, such as chronic jetlag and shift work, has been extensively investigated. However, an evaluation of the effects of chronic jetlag on the mouse pancreatic transcriptome is still lacking. Herein, we report an evaluation of the diurnal variations encountered in the pancreatic transcriptome following exposure to an established chronic jetlag protocol. We found approximately 5.4% of the pancreatic transcriptome was rhythmic. Following chronic jetlag, we found the number of rhythmic transcripts decreased to approximately 3.6% of the transcriptome. Analysis of the core clock genes, which orchestrate circadian physiology, revealed that nearly all exhibited a shift in the timing of peak gene expression-known as a phase shift. Similarly, over 95% of the rhythmically expressed genes in the pancreatic transcriptome exhibited a phase shift, many of which were found to be important for metabolism. Evaluation of the genes involved in pancreatic exocrine secretion and insulin signaling revealed many pancreas-specific genes were also rhythmically expressed and several displayed a concomitant phase shift with chronic jetlag. Phase differences were found 9 days after normalization, indicating a persistent failure to reentrain to the new light-dark cycle. This study is the first to evaluate the endogenous pancreatic clock and rhythmic gene expression in whole pancreas over 48 h, and how the external perturbation of chronic jetlag affects the rhythmic expression of genes in the pancreatic transcriptome.
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Affiliation(s)
- Patrick B Schwartz
- Division of Surgical Oncology, Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Morgan T Walcheck
- Division of Surgical Oncology, Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Mark Berres
- Biotechnology Center, University of Wisconsin, Madison, Wisconsin
| | - Manabu Nukaya
- Division of Surgical Oncology, Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Gang Wu
- Division of Human Genetics and Immunobiology, Center for Chronobiology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Noah D Carrillo
- Division of Surgical Oncology, Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Kristina A Matkowskyj
- Department of Pathology and Laboratory Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
- University of Wisconsin Carbone Cancer Center, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
- William S Middleton Memorial Veterans Hospital, Madison, Wisconsin
| | - Sean M Ronnekleiv-Kelly
- Division of Surgical Oncology, Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
- University of Wisconsin Carbone Cancer Center, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
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14
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Role of High Energy Breakfast "Big Breakfast Diet" in Clock Gene Regulation of Postprandial Hyperglycemia and Weight Loss in Type 2 Diabetes. Nutrients 2021; 13:nu13051558. [PMID: 34063109 PMCID: PMC8148179 DOI: 10.3390/nu13051558] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 04/26/2021] [Accepted: 04/29/2021] [Indexed: 01/15/2023] Open
Abstract
Postprandial hyperglycemia (PPHG) is strongly linked with the future development of cardiovascular complications in type 2 diabetes (T2D). Hence, reducing postprandial glycemic excursions is essential in T2D treatment to slow progressive deficiency of β-cell function and prevent cardiovascular complications. Most of the metabolic processes involved in PPHG, i.e., β-cell secretory function, GLP-1 secretion, insulin sensitivity, muscular glucose uptake, and hepatic glucose production, are controlled by the circadian clock and display daily oscillation. Consequently, postprandial glycemia displays diurnal variation with a higher glycemic response after meals with the same carbohydrate content, consumed at dusk compared to the morning. T2D and meal timing schedule not synchronized with the circadian clock (i.e., skipping breakfast) are associated with disrupted clock gene expression and is linked to PPHG. In contrast, greater intake in the morning (i.e., high energy breakfast) than in the evening has a resetting effect on clock gene oscillations and beneficial effects on weight loss, appetite, and reduction of PPHG, independently of total energy intake. Therefore, resetting clock gene expression through a diet intervention consisting of meal timing aligned to the circadian clock, i.e., shifting most calories and carbohydrates to the early hours of the day, is a promising therapeutic approach to improve PPHG in T2D. This review will focus on recent studies, showing how a high-energy breakfast diet (Bdiet) has resetting and synchronizing actions on circadian clock genes expression, improving glucose metabolism, postprandial glycemic excursions along with weight loss in T2D.
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15
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Javeed N, Brown MR, Rakshit K, Her T, Sen SK, Matveyenko AV. Proinflammatory Cytokine Interleukin 1β Disrupts β-cell Circadian Clock Function and Regulation of Insulin Secretion. Endocrinology 2021; 162:bqaa084. [PMID: 32455427 PMCID: PMC7692023 DOI: 10.1210/endocr/bqaa084] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 05/21/2020] [Indexed: 12/24/2022]
Abstract
Intrinsic β-cell circadian clocks are important regulators of insulin secretion and overall glucose homeostasis. Whether the circadian clock in β-cells is perturbed following exposure to prodiabetogenic stressors such as proinflammatory cytokines, and whether these perturbations are featured during the development of diabetes, remains unknown. To address this, we examined the effects of cytokine-mediated inflammation common to the pathophysiology of diabetes, on the physiological and molecular regulation of the β-cell circadian clock. Specifically, we provide evidence that the key diabetogenic cytokine IL-1β disrupts functionality of the β-cell circadian clock and impairs circadian regulation of glucose-stimulated insulin secretion. The deleterious effects of IL-1β on the circadian clock were attributed to impaired expression of key circadian transcription factor Bmal1, and its regulator, the NAD-dependent deacetylase, Sirtuin 1 (SIRT1). Moreover, we also identified that Type 2 diabetes in humans is associated with reduced immunoreactivity of β-cell BMAL1 and SIRT1, suggestive of a potential causative link between islet inflammation, circadian clock disruption, and β-cell failure. These data suggest that the circadian clock in β-cells is perturbed following exposure to proinflammatory stressors and highlights the potential for therapeutic targeting of the circadian system for treatment for β-cell failure in diabetes.
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Affiliation(s)
- Naureen Javeed
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota
| | - Matthew R Brown
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota
| | - Kuntol Rakshit
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota
| | - Tracy Her
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota
| | - Satish K Sen
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota
| | - Aleksey V Matveyenko
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota
- Department of Medicine, Division of Endocrinology, Metabolism, Diabetes, and Nutrition, Mayo Clinic College of Medicine and Science, Rochester, Minnesota
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16
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Rakshit K, Matveyenko AV. Induction of Core Circadian Clock Transcription Factor Bmal1 Enhances β-Cell Function and Protects Against Obesity-Induced Glucose Intolerance. Diabetes 2021; 70:143-154. [PMID: 33087455 PMCID: PMC7881843 DOI: 10.2337/db20-0192] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 10/15/2020] [Indexed: 12/18/2022]
Abstract
Type 2 diabetes mellitus (T2DM) is characterized by β-cell dysfunction as a result of impaired glucose-stimulated insulin secretion (GSIS). Studies show that β-cell circadian clocks are important regulators of GSIS and glucose homeostasis. These observations raise the question about whether enhancement of the circadian clock in β-cells will confer protection against β-cell dysfunction under diabetogenic conditions. To test this, we used an approach by first generating mice with β-cell-specific inducible overexpression of Bmal1 (core circadian transcription factor; β-Bmal1 OV ). We subsequently examined the effects of β-Bmal1 OV on the circadian clock, GSIS, islet transcriptome, and glucose metabolism in the context of diet-induced obesity. We also tested the effects of circadian clock-enhancing small-molecule nobiletin on GSIS in mouse and human control and T2DM islets. We report that β-Bmal1 OV mice display enhanced islet circadian clock amplitude and augmented in vivo and in vitro GSIS and are protected against obesity-induced glucose intolerance. These effects were associated with increased expression of purported BMAL1-target genes mediating insulin secretion, processing, and lipid metabolism. Furthermore, exposure of isolated islets to nobiletin enhanced β-cell secretory function in a Bmal1-dependent manner. This work suggests therapeutic targeting of the circadian system as a potential strategy to counteract β-cell failure under diabetogenic conditions.
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Affiliation(s)
- Kuntol Rakshit
- Department of Physiology and Biomedical Engineering, Mayo Clinic School of Medicine, Rochester, MN
| | - Aleksey V Matveyenko
- Department of Physiology and Biomedical Engineering, Mayo Clinic School of Medicine, Rochester, MN
- Division of Endocrinology, Metabolism, Diabetes, and Nutrition, Department of Medicine, Mayo Clinic School of Medicine, Rochester, MN
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17
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Martchenko A, Martchenko SE, Biancolin AD, Brubaker PL. Circadian Rhythms and the Gastrointestinal Tract: Relationship to Metabolism and Gut Hormones. Endocrinology 2020; 161:5909225. [PMID: 32954405 PMCID: PMC7660274 DOI: 10.1210/endocr/bqaa167] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 09/16/2020] [Indexed: 02/08/2023]
Abstract
Circadian rhythms are 24-hour biological rhythms within organisms that have developed over evolutionary time due to predefined environmental changes, mainly the light-dark cycle. Interestingly, metabolic tissues, which are largely responsible for establishing diurnal metabolic homeostasis, have been found to express cell-autonomous clocks that are entrained by food intake. Disruption of the circadian system, as seen in individuals who conduct shift work, confers significant risk for the development of metabolic diseases such as type 2 diabetes and obesity. The gastrointestinal (GI) tract is the first point of contact for ingested nutrients and is thus an essential organ system for metabolic control. This review will focus on the circadian function of the GI tract with a particular emphasis on its role in metabolism through regulation of gut hormone release. First, the circadian molecular clock as well as the organization of the mammalian circadian system is introduced. Next, a brief overview of the structure of the gut as well as the circadian regulation of key functions important in establishing metabolic homeostasis is discussed. Particularly, the focus of the review is centered around secretion of gut hormones; however, other functions of the gut such as barrier integrity and intestinal immunity, as well as digestion and absorption, all of which have relevance to metabolic control will be considered. Finally, we provide insight into the effects of circadian disruption on GI function and discuss chronotherapeutic intervention strategies for mitigating associated metabolic dysfunction.
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Affiliation(s)
| | | | | | - Patricia L Brubaker
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Department of Medicine, University of Toronto, Toronto, ON, Canada
- Correspondence: P.L. Brubaker, Rm 3366 Medical Sciences Building, University of Toronto, 1 King’s College Circle, Toronto, ON M5S 1A8 Canada. E-mail:
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18
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Her TK, Lagakos WS, Brown MR, LeBrasseur NK, Rakshit K, Matveyenko AV. Dietary carbohydrates modulate metabolic and β-cell adaptation to high-fat diet-induced obesity. Am J Physiol Endocrinol Metab 2020; 318:E856-E865. [PMID: 32315211 PMCID: PMC7311673 DOI: 10.1152/ajpendo.00539.2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Obesity is associated with several chronic comorbidities, one of which is type 2 diabetes mellitus (T2DM). The pathogenesis of obesity and T2DM is influenced by alterations in diet macronutrient composition, which regulate energy expenditure, metabolic function, glucose homeostasis, and pancreatic islet cell biology. Recent studies suggest that increased intake of dietary carbohydrates plays a previously underappreciated role in the promotion of obesity and consequent metabolic dysfunction. Thus, in this study, we utilized mouse models to test the hypothesis that dietary carbohydrates modulate energetic, metabolic, and islet adaptions to high-fat diets. To address this, we exposed C57BL/6J mice to 12 wk of 3 eucaloric high-fat diets (>60% calories from fat) with varying total carbohydrate (1-20%) and sucrose (0-20%) content. Our results show that severe restriction of dietary carbohydrates characteristic of ketogenic diets reduces body fat accumulation, enhances energy expenditure, and reduces prevailing glycemia and insulin resistance compared with carbohydrate-rich, high-fat diets. Moreover, severe restriction of dietary carbohydrates also results in functional, morphological, and molecular changes in pancreatic islets highlighted by restricted capacity for β-cell mass expansion and alterations in insulin secretory response. These studies support the hypothesis that low-carbohydrate/high-fat diets provide antiobesogenic benefits and suggest further evaluation of the effects of these diets on β-cell biology in humans.
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Affiliation(s)
- Tracy K Her
- Department of Physiology and Biomedical Engineering, Mayo Clinic School of Medicine, Rochester, Minnesota
| | - William S Lagakos
- Department of Physiology and Biomedical Engineering, Mayo Clinic School of Medicine, Rochester, Minnesota
| | - Matthew R Brown
- Department of Physiology and Biomedical Engineering, Mayo Clinic School of Medicine, Rochester, Minnesota
| | - Nathan K LeBrasseur
- Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, Minnesota
| | - Kuntol Rakshit
- Department of Physiology and Biomedical Engineering, Mayo Clinic School of Medicine, Rochester, Minnesota
| | - Aleksey V Matveyenko
- Department of Physiology and Biomedical Engineering, Mayo Clinic School of Medicine, Rochester, Minnesota
- Department of Medicine, Division of Endocrinology, Metabolism, Diabetes, and Nutrition, Mayo Clinic School of Medicine, Rochester, Minnesota
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19
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Jakubowicz D, Landau Z, Tsameret S, Wainstein J, Raz I, Ahren B, Chapnik N, Barnea M, Ganz T, Menaged M, Mor N, Bar-Dayan Y, Froy O. Reduction in Glycated Hemoglobin and Daily Insulin Dose Alongside Circadian Clock Upregulation in Patients With Type 2 Diabetes Consuming a Three-Meal Diet: A Randomized Clinical Trial. Diabetes Care 2019; 42:2171-2180. [PMID: 31548244 DOI: 10.2337/dc19-1142] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 08/26/2019] [Indexed: 02/03/2023]
Abstract
OBJECTIVE In type 2 diabetes, insulin resistance and progressive β-cell failure require treatment with high insulin doses, leading to weight gain. Our aim was to study whether a three-meal diet (3Mdiet) with a carbohydrate-rich breakfast may upregulate clock gene expression and, as a result, allow dose reduction of insulin, leading to weight loss and better glycemic control compared with an isocaloric six-meal diet (6Mdiet). RESEARCH DESIGN AND METHODS Twenty-eight volunteers with diabetes (BMI 32.4 ± 5.2 kg/m2 and HbA1c 8.1 ± 1.1% [64.5 ± 11.9 mmol/mol]) were randomly assigned to 3Mdiet or 6Mdiet. Body weight, glycemic control, continuous glucose monitoring (CGM), appetite, and clock gene expression were assessed at baseline, after 2 weeks, and after 12 weeks. RESULTS 3Mdiet, but not 6Mdiet, led to a significant weight loss (-5.4 ± 0.9 kg) (P < 0.01) and decreased HbA1c (-12 mmol/mol [-1.2%]) (P < 0.0001) after 12 weeks. Fasting glucose and daily and nocturnal glucose levels were significantly lower on the 3Mdiet. CGM showed a significant decrease in the time spent in hyperglycemia only on the 3Mdiet. Total daily insulin dose was significantly reduced by 26 ± 7 units only on the 3Mdiet. There was a significant decrease in the hunger and cravings only in the 3Mdiet group. Clock genes exhibited oscillation, increased expression, and higher amplitude on the 3Mdiet compared with the 6Mdiet. CONCLUSIONS A 3Mdiet, in contrast to an isocaloric 6Mdiet, leads to weight loss and significant reduction in HbA1c, appetite, and overall glycemia, with a decrease in daily insulin. Upregulation of clock genes seen in this diet intervention could contribute to the improved glucose metabolism.
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Affiliation(s)
- Daniela Jakubowicz
- Diabetes Unit, Wolfson Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Holon, Israel
| | - Zohar Landau
- Diabetes Unit, Wolfson Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Holon, Israel
| | - Shani Tsameret
- Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Julio Wainstein
- Diabetes Unit, Wolfson Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Holon, Israel
| | - Itamar Raz
- Diabetes Unit, Department of Internal Medicine, Hadassah Hebrew University Hospital, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Bo Ahren
- Department of Clinical Sciences, Faculty of Medicine, Lund University, Lund, Sweden
| | - Nava Chapnik
- Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Maayan Barnea
- Department of Molecular Genetics, Faculty of Biochemistry, Weizmann Institute of Science, Rehovot, Israel
| | - Tali Ganz
- Diabetes Unit, Wolfson Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Holon, Israel
| | - Miriam Menaged
- Diabetes Unit, Wolfson Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Holon, Israel
| | - Naomi Mor
- Diabetes Unit, Wolfson Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Holon, Israel
| | - Yosefa Bar-Dayan
- Diabetes Unit, Wolfson Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Holon, Israel
| | - Oren Froy
- Institute of Biochemistry, Food Science and Nutrition, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
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20
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Smith DF, Amin RS. OSA and Cardiovascular Risk in Pediatrics. Chest 2019; 156:402-413. [PMID: 30790552 DOI: 10.1016/j.chest.2019.02.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 01/21/2019] [Accepted: 02/08/2019] [Indexed: 02/07/2023] Open
Abstract
OSA occurs in approximately 1% to 5% of children in the United States. Long-term cardiovascular risks associated with OSA in the adult population are well documented. Although changes in BP regulation occur in children with OSA, the pathways leading to chronic cardiovascular risks of OSA in children are less clear. Risk factors associated with cardiovascular disease in adult populations could carry the same future risk for children. It is imperative to determine whether known mechanisms of cardiovascular diseases in adults are like those that lead to pediatric disease. Early pathophysiologic changes may lead to a lifetime burden of cardiovascular disease and early mortality. With this perspective in mind, our review discusses pathways leading to cardiovascular pathology in children with OSA and provides a comprehensive overview of recent research findings related to cardiovascular sequelae in the pediatric population.
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Affiliation(s)
- David F Smith
- Division of Pediatric Otolaryngology-Head and Neck Surgery, Cincinnati Children's Hospital Medical Center, Cincinnati, OH; Division of Pulmonary and Sleep Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH; Department of Otolaryngology-Head and Neck Surgery, University of Cincinnati College of Medicine, Cincinnati, OH
| | - Raouf S Amin
- Division of Pulmonary and Sleep Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH.
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21
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Abstract
The epidemic of Type 2 diabetes mellitus necessitates development of novel therapeutic and preventative strategies to attenuate expansion of this debilitating disease. Evidence links the circadian system to various aspects of diabetes pathophysiology and treatment. The aim of this review will be to outline the rationale for therapeutic targeting of the circadian system in the treatment and prevention of Type 2 diabetes mellitus and consequent metabolic comorbidities.
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Affiliation(s)
- Naureen Javeed
- Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota
| | - Aleksey V Matveyenko
- Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota.,Department of Medicine, Division of Endocrinology, Metabolism, Diabetes, and Nutrition, Mayo Clinic School of Medicine, Mayo Clinic , Rochester, Minnesota
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22
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Lee J, Ma K, Moulik M, Yechoor V. Untimely oxidative stress in β-cells leads to diabetes - Role of circadian clock in β-cell function. Free Radic Biol Med 2018; 119:69-74. [PMID: 29458148 PMCID: PMC5910243 DOI: 10.1016/j.freeradbiomed.2018.02.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 02/12/2018] [Accepted: 02/14/2018] [Indexed: 12/31/2022]
Abstract
Diabetes results from a loss of β-cell function. With the number of people with diabetes reaching epidemic proportions globally, understanding mechanisms that are contributing to this increasing prevalence is critical. One such factor has been circadian disruption, with shift-work, light pollution, jet-lag, increased screen time, all acting as potential contributory factors. Though circadian disruption has been epidemiologically associated with diabetes and other metabolic disorders for many decades, it is only recently that there has been a better understanding of the underlying molecular mechanisms. Experimental circadian disruption, via manipulation of environmental or genetic factors using gene-deletion mouse models, has demonstrated the importance of circadian rhythms in whole body metabolism. Genetic disruption of core clock genes, specifically in the β-cells in mice, have, now demonstrated the importance of the intrinsic β-cell clock in regulating function. Recent work has also shown the interaction of the circadian clock and enhancers in β-cells, indicating a highly integrated regulation of transcription and cellular function by the circadian clock. Disruption of either the whole body or only the β-cell clock leads to significant impairment of mitochondrial function, uncoupling, impaired vesicular transport, oxidative stress in β-cells and finally impaired glucose-stimulated insulin secretion and diabetes. In this review, we explore the role of the circadian clock in mitigating oxidative stress and preserving β-cell function.
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Affiliation(s)
- J Lee
- Diabetes and Beta Cell Biology Center, Division of Endocrinology, Diabetes & Metabolism, Department of Medicine, University of Pittsburgh, 200 Lothrop, BST-1058W, Pittsburgh, PA 15261, United States
| | - K Ma
- Diabetes and Metabolism Research Institute, City of Hope, Duarte, CA, United States
| | - M Moulik
- Division of Cardiology, Department of Pediatrics, Children's Hospital of Pittsburgh and University of Pittsburgh, Pittsburgh, PA, United States
| | - V Yechoor
- Diabetes and Beta Cell Biology Center, Division of Endocrinology, Diabetes & Metabolism, Department of Medicine, University of Pittsburgh, 200 Lothrop, BST-1058W, Pittsburgh, PA 15261, United States.
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23
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Rakshit K, Qian J, Gaonkar KS, Dhawan S, Colwell CS, Matveyenko AV. Postnatal Ontogenesis of the Islet Circadian Clock Plays a Contributory Role in β-Cell Maturation Process. Diabetes 2018; 67:911-922. [PMID: 29500314 PMCID: PMC5910002 DOI: 10.2337/db17-0850] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 02/23/2018] [Indexed: 12/13/2022]
Abstract
Development of cell replacement therapies in diabetes requires understanding of the molecular underpinnings of β-cell maturation. The circadian clock regulates diverse cellular functions important for regulation of β-cell function and turnover. However, postnatal ontogenesis of the islet circadian clock and its potential role in β-cell maturation remain unknown. To address this, we studied wild-type Sprague-Dawley as well as Period1 luciferase transgenic (Per1:LUC) rats to determine circadian clock function, clock protein expression, and diurnal insulin secretion during islet development and maturation process. We additionally studied β-cell-specific Bmal1-deficient mice to elucidate a potential role of this key circadian transcription factor in β-cell functional and transcriptional maturation. We report that emergence of the islet circadian clock 1) occurs during the early postnatal period, 2) depends on the establishment of global behavioral circadian rhythms, and 3) leads to the induction of diurnal insulin secretion and gene expression. Islet cell maturation was also characterized by induction in the expression of circadian transcription factor BMAL1, deletion of which altered postnatal development of glucose-stimulated insulin secretion and the associated transcriptional network. Postnatal development of the islet circadian clock contributes to early-life β-cell maturation and should be considered for optimal design of future β-cell replacement strategies in diabetes.
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Affiliation(s)
- Kuntol Rakshit
- Department of Physiology and Biomedical Engineering, Mayo Clinic School of Medicine, Mayo Clinic, Rochester, MN
| | - Jingyi Qian
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA
| | - Krutika Satish Gaonkar
- Division of Biostatistics and Informatics, Department of Health Sciences Research, Mayo Clinic School of Medicine, Mayo Clinic, Rochester, MN
| | - Sangeeta Dhawan
- Department of Translational Research & Cellular Therapeutics, City of Hope, Duarte, CA
| | - Christopher S Colwell
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA
| | - Aleksey V Matveyenko
- Department of Physiology and Biomedical Engineering, Mayo Clinic School of Medicine, Mayo Clinic, Rochester, MN
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24
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Montemurro C, Vadrevu S, Gurlo T, Butler AE, Vongbunyong KE, Petcherski A, Shirihai OS, Satin LS, Braas D, Butler PC, Tudzarova S. Cell cycle-related metabolism and mitochondrial dynamics in a replication-competent pancreatic beta-cell line. Cell Cycle 2017; 16:2086-2099. [PMID: 28820316 DOI: 10.1080/15384101.2017.1361069] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Cell replication is a fundamental attribute of growth and repair in multicellular organisms. Pancreatic beta-cells in adults rarely enter cell cycle, hindering the capacity for regeneration in diabetes. Efforts to drive beta-cells into cell cycle have so far largely focused on regulatory molecules such as cyclins and cyclin-dependent kinases (CDKs). Investigations in cancer biology have uncovered that adaptive changes in metabolism, the mitochondrial network, and cellular Ca2+ are critical for permitting cells to progress through the cell cycle. Here, we investigated these parameters in the replication-competent beta-cell line INS 832/13. Cell cycle synchronization of this line permitted evaluation of cell metabolism, mitochondrial network, and cellular Ca2+ compartmentalization at key cell cycle stages. The mitochondrial network is interconnected and filamentous at G1/S but fragments during the S and G2/M phases, presumably to permit sorting to daughter cells. Pyruvate anaplerosis peaks at G1/S, consistent with generation of biomass for daughter cells, whereas mitochondrial Ca2+ and respiration increase during S and G2/M, consistent with increased energy requirements for DNA and lipid synthesis. This synchronization approach may be of value to investigators performing live cell imaging of Ca2+ or mitochondrial dynamics commonly undertaken in INS cell lines because without synchrony widely disparate data from cell to cell would be expected depending on position within cell cycle. Our findings also offer insight into why replicating beta-cells are relatively nonfunctional secreting insulin in response to glucose. They also provide guidance on metabolic requirements of beta-cells for the transition through the cell cycle that may complement the efforts currently restricted to manipulating cell cycle to drive beta-cells through cell cycle.
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Affiliation(s)
- Chiara Montemurro
- a Larry L. Hillblom Islet Research Center , University of California, Los Angeles, David Geffen School of Medicine , Los Angeles , CA , USA
| | - Suryakiran Vadrevu
- b Department of Pharmacology and Brehm Diabetes Research Center , University of Michigan , Ann Arbor , MI , USA
| | - Tatyana Gurlo
- a Larry L. Hillblom Islet Research Center , University of California, Los Angeles, David Geffen School of Medicine , Los Angeles , CA , USA
| | - Alexandra E Butler
- a Larry L. Hillblom Islet Research Center , University of California, Los Angeles, David Geffen School of Medicine , Los Angeles , CA , USA
| | - Kenny E Vongbunyong
- a Larry L. Hillblom Islet Research Center , University of California, Los Angeles, David Geffen School of Medicine , Los Angeles , CA , USA
| | - Anton Petcherski
- c Division of Endocrinology, Department of Medicine, David Geffen School of Medicine , University of California, Los Angeles , Los Angeles , CA , USA
| | - Orian S Shirihai
- c Division of Endocrinology, Department of Medicine, David Geffen School of Medicine , University of California, Los Angeles , Los Angeles , CA , USA
| | - Leslie S Satin
- b Department of Pharmacology and Brehm Diabetes Research Center , University of Michigan , Ann Arbor , MI , USA
| | - Daniel Braas
- d Department of Molecular and Medical Pharmacology, Crump Institute for Molecular Imaging , University of California, Los Angeles, David Geffen School of Medicine , Los Angeles , CA , USA ; UCLA Metabolomics Center , University of California, Los Angeles , Los Angeles , CA , USA
| | - Peter C Butler
- a Larry L. Hillblom Islet Research Center , University of California, Los Angeles, David Geffen School of Medicine , Los Angeles , CA , USA
| | - Slavica Tudzarova
- a Larry L. Hillblom Islet Research Center , University of California, Los Angeles, David Geffen School of Medicine , Los Angeles , CA , USA.,e Jonsson Comprehensive Cancer Center , University of California, Los Angeles, David Geffen School of Medicine , Los Angeles , CA , USA
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25
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Sharma A, Laurenti MC, Dalla Man C, Varghese RT, Cobelli C, Rizza RA, Matveyenko A, Vella A. Glucose metabolism during rotational shift-work in healthcare workers. Diabetologia 2017; 60:1483-1490. [PMID: 28551698 PMCID: PMC5860643 DOI: 10.1007/s00125-017-4317-0] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 04/26/2017] [Indexed: 01/05/2023]
Abstract
AIMS/HYPOTHESIS Shift-work is associated with circadian rhythm disruption and an increased risk of obesity and type 2 diabetes. We sought to determine the effect of rotational shift-work on glucose metabolism in humans. METHODS We studied 12 otherwise healthy nurses performing rotational shift-work using a randomised crossover study design. On each occasion, participants underwent an isotope-labelled mixed meal test during a simulated day shift and a simulated night shift, enabling simultaneous measurement of glucose flux and beta cell function using the oral minimal model. We sought to determine differences in fasting and postprandial glucose metabolism during the day shift vs the night shift. RESULTS Postprandial glycaemic excursion was higher during the night shift (381±33 vs 580±48 mmol/l per 5 h, p<0.01). The time to peak insulin and C-peptide and nadir glucagon suppression in response to meal ingestion was also delayed during the night shift. While insulin action did not differ between study days, the beta cell responsivity to glucose (59±5 vs 44±4 × 10-9 min-1; p<0.001) and disposition index were decreased during the night shift. CONCLUSIONS/INTERPRETATION Impaired beta cell function during the night shift may result from normal circadian variation, the effect of rotational shift-work or a combination of both. As a consequence, higher postprandial glucose concentrations are observed during the night shift.
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Affiliation(s)
- Anu Sharma
- Endocrine Research Unit, Department of Endocrinology, Diabetes and Nutrition, Mayo Clinic College of Medicine, 200 First St SW, 5-194 Joseph, Rochester, MN, 55905, USA
| | | | - Chiara Dalla Man
- Department of Information Engineering, University of Padua, Padua, Italy
| | - Ron T Varghese
- Endocrine Research Unit, Department of Endocrinology, Diabetes and Nutrition, Mayo Clinic College of Medicine, 200 First St SW, 5-194 Joseph, Rochester, MN, 55905, USA
| | - Claudio Cobelli
- Department of Information Engineering, University of Padua, Padua, Italy
| | - Robert A Rizza
- Endocrine Research Unit, Department of Endocrinology, Diabetes and Nutrition, Mayo Clinic College of Medicine, 200 First St SW, 5-194 Joseph, Rochester, MN, 55905, USA
| | - Aleksey Matveyenko
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
| | - Adrian Vella
- Endocrine Research Unit, Department of Endocrinology, Diabetes and Nutrition, Mayo Clinic College of Medicine, 200 First St SW, 5-194 Joseph, Rochester, MN, 55905, USA.
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26
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Seshadri N, Jonasson ME, Hunt KL, Xiang B, Cooper S, Wheeler MB, Dolinsky VW, Doucette CA. Uncoupling protein 2 regulates daily rhythms of insulin secretion capacity in MIN6 cells and isolated islets from male mice. Mol Metab 2017; 6:760-769. [PMID: 28702331 PMCID: PMC5485245 DOI: 10.1016/j.molmet.2017.04.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 04/16/2017] [Accepted: 04/24/2017] [Indexed: 12/17/2022] Open
Abstract
Objective Upregulation of uncoupling protein 2 (UCP2) is associated with impaired glucose-stimulated insulin secretion (GSIS), which is thought to be an important contributor to pathological β cell failure in obesity and type 2 diabetes (T2D); however, the physiological function of UCP2 in the β cell remains undefined. It has been suggested, but not yet tested, that UCP2 plays a physiological role in β cells by coordinating insulin secretion capacity with anticipated fluctuating nutrient supply, such that upregulation of UCP2 in the inactive/fasted state inhibits GSIS as a mechanism to prevent hypoglycemia. Therefore, we hypothesized that daily cycles of GSIS capacity are dependent on rhythmic and predictable patterns of Ucp2 gene expression such that low Ucp2 in the active/fed phase promotes maximal GSIS capacity, whereas elevated Ucp2 expression in the inactive/fasted phase supresses GSIS capacity. We further hypothesized that rhythmic Ucp2 expression is required for the maintenance of glucose tolerance over the 24 h cycle. Methods We used synchronized MIN6 clonal β cells and isolated mouse islets from wild type (C57BL6) and mice with β cell knockout of Ucp2 (Ucp2-βKO; and respective Ins2-cre controls) to determine the endogenous expression pattern of Ucp2 over 24 h and its impact on GSIS capacity and glucose tolerance over 24 h. Results A dynamic pattern of Ucp2 mRNA expression was observed in synchronized MIN6 cells, which showed a reciprocal relationship with GSIS capacity in a time-of-day-specific manner. GSIS capacity was suppressed in islets isolated from wild type and control mice during the light/inactive phase of the daily cycle; a suppression that was dependent on Ucp2 in the β cell and was lost in islets isolated from Ucp2-βKO mice or wild type islets treated with a UCP2 inhibitor. Finally, suppression of GSIS capacity by UCP2 in the light phase was required for the maintenance of normal patterns of glucose tolerance. Conclusions Our study suggests that Ucp2/UCP2 in the β cell is part of an important, endogenous, metabolic regulator that controls the temporal capacity of GSIS over the course of the day/night cycle, which, in turn, regulates time-of-day glucose tolerance. Targeting Ucp2/UCP2 as a therapeutic in type 2 diabetes or any other metabolic condition must take into account the rhythmic nature of its expression and its impact on glucose tolerance over 24 h, specifically during the inactive/fasted phase. Ucp2 mRNA expression in MIN6 β cells and isolated islets is dynamic and rhythmic over 24 h. Daily cycles of glucose-stimulated insulin secretion capacity are dependent on rhythmic Ucp2 expression and UCP2 activity. Loss of rhythmic Ucp2 mRNA expression triggers glucose intolerance only in the light/inactive phase of the daily cycle. UCP2 is part of an endogenous diurnal metabolic regulator that coordinates islet function with the daily cycle of fasting and feeding.
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Key Words
- GSIS, Glucose-stimulated insulin secretion
- Glucose tolerance
- Glucose-stimulated insulin secretion
- HG, High glucose
- Ins2-cre, Ins2 promoter-driven cre recombinase
- LG, Low glucose
- MIN6, Mouse insulinoma 6
- Pancreatic islets
- T2D, Type 2 diabetes
- UCP2, Uncoupling protein 2
- Ucp2-βKO, β cell-specific Ucp2 knockout
- Uncoupling protein 2
- WT, wild type
- ZT, Zeitgeber time
- i.p.GTT, intraperitoneal glucose tolerance test
- β cells
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Affiliation(s)
- Nivedita Seshadri
- Univerisity of Manitoba, Department of Physiology and Pathophysiology, Winnipeg, MB, R3E 0J9, Canada.,The Children's Hospital Research Institute of Manitoba, Diabetes Research Envisioned and Accomplished in Manitoba (DREAM) Theme, Winnipeg, MB, R3E 3P4, Canada
| | - Michael E Jonasson
- The Children's Hospital Research Institute of Manitoba, Diabetes Research Envisioned and Accomplished in Manitoba (DREAM) Theme, Winnipeg, MB, R3E 3P4, Canada
| | - Kristin L Hunt
- Univerisity of Manitoba, Department of Physiology and Pathophysiology, Winnipeg, MB, R3E 0J9, Canada.,The Children's Hospital Research Institute of Manitoba, Diabetes Research Envisioned and Accomplished in Manitoba (DREAM) Theme, Winnipeg, MB, R3E 3P4, Canada
| | - Bo Xiang
- The Children's Hospital Research Institute of Manitoba, Diabetes Research Envisioned and Accomplished in Manitoba (DREAM) Theme, Winnipeg, MB, R3E 3P4, Canada.,University of Manitoba, Department of Pharmacology & Therapeutics, Winnipeg, MB, R3E 0T6, Canada
| | - Steven Cooper
- The Children's Hospital Research Institute of Manitoba, Diabetes Research Envisioned and Accomplished in Manitoba (DREAM) Theme, Winnipeg, MB, R3E 3P4, Canada
| | - Michael B Wheeler
- University of Toronto, Department of Physiology, Toronto, ON, M5S 1A8, Canada
| | - Vernon W Dolinsky
- The Children's Hospital Research Institute of Manitoba, Diabetes Research Envisioned and Accomplished in Manitoba (DREAM) Theme, Winnipeg, MB, R3E 3P4, Canada.,University of Manitoba, Department of Pharmacology & Therapeutics, Winnipeg, MB, R3E 0T6, Canada
| | - Christine A Doucette
- Univerisity of Manitoba, Department of Physiology and Pathophysiology, Winnipeg, MB, R3E 0J9, Canada.,The Children's Hospital Research Institute of Manitoba, Diabetes Research Envisioned and Accomplished in Manitoba (DREAM) Theme, Winnipeg, MB, R3E 3P4, Canada
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