1
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Seo S, Kim YA, Lee Y, Kim YJ, Kim BJ, An JH, Jin H, Do AR, Park K, Won S, Seo JH. Epigenetic link between Agent Orange exposure and type 2 diabetes in Korean veterans. Front Endocrinol (Lausanne) 2024; 15:1375459. [PMID: 39072272 PMCID: PMC11272593 DOI: 10.3389/fendo.2024.1375459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 06/24/2024] [Indexed: 07/30/2024] Open
Abstract
Conflicting findings have been reported regarding the association between Agent Orange (AO) exposure and type 2 diabetes. This study aimed to examine whether AO exposure is associated with the development of type 2 diabetes and to verify the causal relationship between AO exposure and type 2 diabetes by combining DNA methylation with DNA genotype analyses. An epigenome-wide association study and DNA genotype analyses of the blood of AO-exposed and AO-unexposed individuals with type 2 diabetes and that of healthy controls were performed. Methylation quantitative trait locus and Mendelian randomisation analyses were performed to evaluate the causal effect of AO-exposure-identified CpGs on type 2 diabetes. AO-exposed individuals with type 2 diabetes were associated with six hypermethylated CpG sites (cg20075319, cg21757266, cg05203217, cg20102280, cg26081717, and cg21878650) and one hypo-methylated CpG site (cg07553761). Methylation quantitative trait locus analysis showed the methylation levels of some CpG sites (cg20075319, cg20102280, and cg26081717) to be significantly different. Mendelian randomisation analysis showed that CpG sites that were differentially methylated in AO-exposed individuals were causally associated with type 2 diabetes; the reverse causal effect was not significant. These findings reflect the need for further epigenetic studies on the causal relationship between AO exposure and type 2 diabetes.
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Affiliation(s)
- Sujin Seo
- Department of Public Health Science, Graduate School of Public Health, Seoul National University, Seoul, Republic of Korea
| | - Ye An Kim
- Division of Endocrinology, Department of Internal Medicine, Veterans Health Service Medical Center, Seoul, Republic of Korea
| | - Young Lee
- Veterans Medical Research Institute, Veterans Health Service Medical Center, Seoul, Republic of Korea
| | - Young Jin Kim
- Division of Genome Science, Department of Precision Medicine, National Institute of Health, Cheongju-si, Republic of Korea
| | - Bong-Jo Kim
- Division of Genome Science, Department of Precision Medicine, National Institute of Health, Cheongju-si, Republic of Korea
| | - Jae Hoon An
- Institute of Health and Environment, Seoul National University, Seoul, Republic of Korea
| | - Heejin Jin
- Institute of Health and Environment, Seoul National University, Seoul, Republic of Korea
| | - Ah Ra Do
- Interdisciplinary Program of Bioinformatics, College of National Sciences, Seoul National University, Seoul, Republic of Korea
| | - Kyungtaek Park
- Institute of Health and Environment, Seoul National University, Seoul, Republic of Korea
| | - Sungho Won
- Department of Public Health Science, Graduate School of Public Health, Seoul National University, Seoul, Republic of Korea
- Institute of Health and Environment, Seoul National University, Seoul, Republic of Korea
- Interdisciplinary Program of Bioinformatics, College of National Sciences, Seoul National University, Seoul, Republic of Korea
| | - Je Hyun Seo
- Veterans Medical Research Institute, Veterans Health Service Medical Center, Seoul, Republic of Korea
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Wang N, Zhang C. Oxidative Stress: A Culprit in the Progression of Diabetic Kidney Disease. Antioxidants (Basel) 2024; 13:455. [PMID: 38671903 PMCID: PMC11047699 DOI: 10.3390/antiox13040455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 04/01/2024] [Accepted: 04/10/2024] [Indexed: 04/28/2024] Open
Abstract
Diabetic kidney disease (DKD) is the principal culprit behind chronic kidney disease (CKD), ultimately developing end-stage renal disease (ESRD) and necessitating costly dialysis or kidney transplantation. The limited therapeutic efficiency among individuals with DKD is a result of our finite understanding of its pathogenesis. DKD is the result of complex interactions between various factors. Oxidative stress is a fundamental factor that can establish a link between hyperglycemia and the vascular complications frequently encountered in diabetes, particularly DKD. It is crucial to recognize the essential and integral role of oxidative stress in the development of diabetic vascular complications, particularly DKD. Hyperglycemia is the primary culprit that can trigger an upsurge in the production of reactive oxygen species (ROS), ultimately sparking oxidative stress. The main endogenous sources of ROS include mitochondrial ROS production, NADPH oxidases (Nox), uncoupled endothelial nitric oxide synthase (eNOS), xanthine oxidase (XO), cytochrome P450 (CYP450), and lipoxygenase. Under persistent high glucose levels, immune cells, the complement system, advanced glycation end products (AGEs), protein kinase C (PKC), polyol pathway, and the hexosamine pathway are activated. Consequently, the oxidant-antioxidant balance within the body is disrupted, which triggers a series of reactions in various downstream pathways, including phosphoinositide 3-kinase/protein kinase B (PI3K/Akt), transforming growth factor beta/p38-mitogen-activated protein kinase (TGF-β/p38-MAPK), nuclear factor kappa B (NF-κB), adenosine monophosphate-activated protein kinase (AMPK), and the Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling. The disease might persist even if strict glucose control is achieved, which can be attributed to epigenetic modifications. The treatment of DKD remains an unresolved issue. Therefore, reducing ROS is an intriguing therapeutic target. The clinical trials have shown that bardoxolone methyl, a nuclear factor erythroid 2-related factor 2 (Nrf2) activator, blood glucose-lowering drugs, such as sodium-glucose cotransporter 2 inhibitors, and glucagon-like peptide-1 receptor agonists can effectively slow down the progression of DKD by reducing oxidative stress. Other antioxidants, including vitamins, lipoic acid, Nox inhibitors, epigenetic regulators, and complement inhibitors, present a promising therapeutic option for the treatment of DKD. In this review, we conduct a thorough assessment of both preclinical studies and current findings from clinical studies that focus on targeted interventions aimed at manipulating these pathways. We aim to provide a comprehensive overview of the current state of research in this area and identify key areas for future exploration.
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Affiliation(s)
| | - Chun Zhang
- Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
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3
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Raghubeer S. The influence of epigenetics and inflammation on cardiometabolic risks. Semin Cell Dev Biol 2024; 154:175-184. [PMID: 36804178 DOI: 10.1016/j.semcdb.2023.02.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 02/13/2023] [Accepted: 02/13/2023] [Indexed: 02/18/2023]
Abstract
Cardiometabolic diseases include metabolic syndrome, obesity, type 2 diabetes mellitus, and hypertension. Epigenetic modifications participate in cardiometabolic diseases through several pathways, including inflammation, vascular dysfunction, and insulin resistance. Epigenetic modifications, which encompass alterations to gene expression without mutating the DNA sequence, have gained much attention in recent years, since they have been correlated with cardiometabolic diseases and may be targeted for therapeutic interventions. Epigenetic modifications are greatly influenced by environmental factors, such as diet, physical activity, cigarette smoking, and pollution. Some modifications are heritable, indicating that the biological expression of epigenetic alterations may be observed across generations. Moreover, many patients with cardiometabolic diseases present with chronic inflammation, which can be influenced by environmental and genetic factors. The inflammatory environment worsens the prognosis of cardiometabolic diseases and further induces epigenetic modifications, predisposing patients to the development of other metabolism-associated diseases and complications. A deeper understanding of inflammatory processes and epigenetic modifications in cardiometabolic diseases is necessary to improve our diagnostic capabilities, personalized medicine approaches, and the development of targeted therapeutic interventions. Further understanding may also assist in predicting disease outcomes, especially in children and young adults. This review describes epigenetic modifications and inflammatory processes underlying cardiometabolic diseases, and further discusses advances in the research field with a focus on specific points for interventional therapy.
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Affiliation(s)
- Shanel Raghubeer
- SAMRC/CPUT/Cardiometabolic Health Research Unit, Department of Biomedical Sciences, Faculty of Health & Wellness Sciences, Cape Peninsula University of Technology, South Africa.
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Akhouri V, Majumder S, Gaikwad AB. Targeting DNA methylation in diabetic kidney disease: A new perspective. Life Sci 2023; 335:122256. [PMID: 37949210 DOI: 10.1016/j.lfs.2023.122256] [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: 09/20/2023] [Revised: 10/30/2023] [Accepted: 11/06/2023] [Indexed: 11/12/2023]
Abstract
Diabetic kidney disease (DKD) is a leading diabetic complication causing significant mortality among people around the globe. People with poor glycemic control accompanied by hyperinsulinemia, dyslipidemia, hypertension, and obesity develop diabetic complications. These diabetic patients develop epigenetic changes and suffer from diabetic kidney complications even after subsequent glucose control, the phenomenon that is recognized as metabolic memory. DNA methylation is an essential epigenetic modification that contributes to the development and progression of several diabetic complications, including DKD. The aberrant DNA methylation pattern at CpGs sites within several genes, such as mTOR, RPTOR, IRS2, GRK5, SLC27A3, LCAT, and SLC1A5, associated with the accompanying risk factors exacerbate the DKD progression. Although drugs such as azacytidine and decitabine have been approved to target DNA methylation for diseases such as hematological malignancies, none have been approved for the treatment of DKD. More importantly, no DNA hypomethylation-targeting drugs have been approved for any disease conditions. Understanding the alteration in DNA methylation and its association with the disease risk factors is essential to target DKD effectively. This review has discussed the abnormal DNA methylation pattern and the kidney tissue-specific expression of critical genes involved in DKD onset and progression. Moreover, we also discuss the new possible therapeutic approach that can be exploited for treating DNA methylation aberrancy in a site-specific manner against DKD.
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Affiliation(s)
- Vivek Akhouri
- Department of Pharmacy, Birla Institute of Technology and Science Pilani, Pilani Campus, Rajasthan 333031, India
| | - Syamantak Majumder
- Department of Biological Sciences, Birla Institute of Technology and Science Pilani, Pilani Campus, Rajasthan 333031, India
| | - Anil Bhanudas Gaikwad
- Department of Pharmacy, Birla Institute of Technology and Science Pilani, Pilani Campus, Rajasthan 333031, India.
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Seo H, Park JH, Hwang JT, Choi HK, Park SH, Lee J. Epigenetic Profiling of Type 2 Diabetes Mellitus: An Epigenome-Wide Association Study of DNA Methylation in the Korean Genome and Epidemiology Study. Genes (Basel) 2023; 14:2207. [PMID: 38137029 PMCID: PMC10743302 DOI: 10.3390/genes14122207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 12/08/2023] [Accepted: 12/12/2023] [Indexed: 12/24/2023] Open
Abstract
Diabetes is characterized by persistently high blood glucose levels and severe complications and affects millions of people worldwide. In this study, we explored the epigenetic landscape of diabetes using data from the Korean Genome and Epidemiology Study (KoGES), specifically the Ansung-Ansan (AS-AS) cohort. Using epigenome-wide association studies, we investigated DNA methylation patterns in patients with type 2 diabetes mellitus (T2DM) and those with normal glucose regulation. Differential methylation analysis revealed 106 differentially methylated probes (DMPs), with the 10 top DMPs prominently associated with TXNIP, PDK4, NBPF20, ARRDC4, UFM1, PFKFB2, C7orf50, and ABCG1, indicating significant changes in methylation. Correlation analysis highlighted the association between the leading DMPs (e.g., cg19693031 and cg26974062 for TXNIP and cg26823705 for NBPF20) and key glycemic markers (fasting plasma glucose and hemoglobin A1c), confirming their relevance in T2DM. Moreover, we identified 62 significantly differentially methylated regions (DMRs) spanning 61 genes. A DMR associated with PDE1C showed hypermethylation, whereas DMRs associated with DIP2C, FLJ90757, PRSS50, and TDRD9 showed hypomethylation. PDE1C and TDRD9 showed a strong positive correlation between the CpG sites included in each DMR, which have previously been implicated in T2DM-related processes. This study contributes to the understanding of epigenetic modifications in T2DM. These valuable insights can be utilized in identifying potential biomarkers and therapeutic targets for effective management and prevention of diabetes.
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Affiliation(s)
| | | | | | | | | | - Jangho Lee
- Korea Food Research Institute, Wanju-gun 55365, Jeollabuk-do, Republic of Korea; (H.S.); (J.-H.P.); (J.-T.H.); (H.-K.C.); (S.-H.P.)
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6
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Sharma S, Bhonde R. Applicability of mesenchymal stem cell-derived exosomes as a cell-free miRNA therapy and epigenetic modifiers for diabetes. Epigenomics 2023; 15:1323-1336. [PMID: 38018455 DOI: 10.2217/epi-2023-0302] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2023] Open
Abstract
Given that exosome nanovesicles constitute various growth factors, miRNAs and lncRNAs, they have implications for epigenetic modifications. Few studies have shown that exosomes from mesenchymal stem cells (MSCs) exhibit therapeutic effects on diabetic complications by substituting miRNAs and regulating histone modifications. Therefore, reversing epigenetic aberrations in diabetes may provide new insight into its treatment. This review discusses the impact of DNA and histone methylations on the development of diabetes and its complications. Further, we talk about miRNAs dysregulated in diabetic conditions and the possibility of utilizing mesenchymal stem cell (MSC) exosomes for the development of miRNA cell-free therapy and epigenetic modifiers in reversing diabetic-induced epigenetic alterations.
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Affiliation(s)
- Shikha Sharma
- Institute For Stem Cell Science & Regenerative Medicine, Bangalore, 560065, India
| | - Ramesh Bhonde
- Dr D.Y. Patil Vidyapeeth, Pimpri, Pune, 411018, India
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Venkataraghavan S, Pankow JS, Boerwinkle E, Fornage M, Selvin E, Ray D. Epigenome-wide association study of incident type 2 diabetes in Black and White participants from the Atherosclerosis Risk in Communities Study. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.08.09.23293896. [PMID: 37609313 PMCID: PMC10441493 DOI: 10.1101/2023.08.09.23293896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
DNA methylation studies of incident type 2 diabetes in US populations are limited, and to our knowledge none included individuals of African descent living in the US. We performed an epigenome-wide association analysis of blood-based methylation levels at CpG sites with incident type 2 diabetes using Cox regression in 2,091 Black and 1,029 White individuals from the Atherosclerosis Risk in Communities study. At an epigenome-wide significance threshold of 10-7, we detected 7 novel diabetes-associated CpG sites in C1orf151 (cg05380846: HR= 0.89, p = 8.4 × 10-12), ZNF2 (cg01585592: HR= 0.88, p = 1.6 × 10-9), JPH3 (cg16696007: HR= 0.87, p = 7.8 × 10-9), GPX6 (cg02793507: HR= 0.85, p = 2.7 × 10-8 and cg00647063: HR= 1.20, p = 2.5 × 10-8), chr17q25 (cg16865890: HR= 0.8, p = 6.9 × 10-8), and chr11p15 (cg13738793: HR= 1.11, p = 7.7 × 10-8). The CpG sites at C1orf151, ZNF2, JPH3 and GPX6, were identified in Black adults, chr17q25 was identified in White adults, and chr11p15 was identified upon meta-analyzing the two groups. The CpG sites at JPH3 and GPX6 were likely associated with incident type 2 diabetes independent of BMI. All the CpG sites, except at JPH3, were likely consequences of elevated glucose at baseline. We additionally replicated known type 2 diabetes-associated CpG sites including cg19693031 at TXNIP, cg00574958 at CPT1A, cg16567056 at PLBC2, cg11024682 at SREBF1, cg08857797 at VPS25, and cg06500161 at ABCG1, 3 of which were replicated in Black adults at the epigenome-wide threshold. We observed modest increase in type 2 diabetes variance explained upon addition of the significantly associated CpG sites to a Cox model that included traditional type 2 diabetes risk factors and fasting glucose (increase from 26.2% to 30.5% in Black adults; increase from 36.9% to 39.4% in White adults). We examined if groups of proximal CpG sites were associated with incident type 2 diabetes using a gene-region specific and a gene-region agnostic differentially methylated region (DMR) analysis. Our DMR analyses revealed several clusters of significant CpG sites, including a DMR consisting of a previously discovered CpG site at ADCY7 and promoter regions of TP63 which were differentially methylated across all race groups. This study illustrates improved discovery of CpG sites/regions by leveraging both individual CpG site and DMR analyses in an unexplored population. Our findings include genes linked to diabetes in experimental studies (e.g., GPX6, JPH3, and TP63), and future gene-specific methylation studies could elucidate the link between genes, environment, and methylation in the pathogenesis of type 2 diabetes.
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Affiliation(s)
- Sowmya Venkataraghavan
- Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - James S. Pankow
- Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis, Minnesota, United States of American
| | - Eric Boerwinkle
- The UTHealth School of Public Health, Houston, Texas, United States of America
| | - Myriam Fornage
- Brown Foundation Institute for Molecular Medicine, The University of Texas Health Science Center, Houston, Texas, United States of America
| | - Elizabeth Selvin
- Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
- Welch Center for Prevention, Epidemiology, & Clinical Research, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Debashree Ray
- Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
- Department of Biostatistics, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
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8
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Wang W, Yao W, Tan Q, Li S, Duan H, Tian X, Xu C, Zhang D. Identification of key DNA methylation changes on fasting plasma glucose: a genome-wide DNA methylation analysis in Chinese monozygotic twins. Diabetol Metab Syndr 2023; 15:159. [PMID: 37461060 PMCID: PMC10351111 DOI: 10.1186/s13098-023-01136-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 07/09/2023] [Indexed: 07/21/2023] Open
Abstract
BACKGROUND Elevated fasting plasma glucose (FPG) levels can increase morbidity and mortality even when it is below the diagnostic threshold of type 2 diabetes mellitus (T2DM). We conducted a genome-wide DNA methylation analysis to detect DNA methylation (DNAm) variants potentially related to FPG in Chinese monozygotic twins. METHODS Genome-wide DNA methylation profiling in whole blood of twins was performed using Reduced Representation Bisulfite Sequencing (RRBS), yielding 551,447 raw CpGs. Association between DNAm of single CpG and FPG was tested using a generalized estimation equation. Differentially methylated regions (DMRs) were identified using comb-P approach. ICE FALCON method was utilized to perform the causal inference. Candidate CpGs were quantified and validated using Sequenom MassARRAY platform in a community population. Weighted gene co-expression network analysis (WGCNA) was conducted using gene expression data from twins. RESULTS The mean age of 52 twin pairs was 52 years (SD: 7). The relationship between DNAm of 142 CpGs and FPG reached the genome-wide significance level. Thirty-two DMRs within 24 genes were identified, including TLCD1, MRPS31P5, CASZ1, and CXADRP3. The causal relationship of top CpGs mapped to TLCD1, MZF1, PTPRN2, SLC6A18, ASTN2, IQCA1, GRIN1, and PDE2A genes with FPG were further identified using ICE FALCON method. Pathways potentially related to FPG were also identified, such as phospholipid-hydroperoxide glutathione peroxidase activity and mitogen-activated protein kinase p38 binding. Three CpGs mapped to SLC6A18 gene were validated in a community population, with a hypermethylated direction in diabetic patients. The expression levels of 18 genes (including SLC6A18 and TLCD1) were positively correlated with FPG levels. CONCLUSIONS We detect many DNAm variants that may be associated with FPG in whole blood, particularly the loci within SLC6A18 gene. Our findings provide important reference for the epigenetic regulation of elevated FPG levels and diabetes.
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Affiliation(s)
- Weijing Wang
- Department of Epidemiology and Health Statistics, School of Public Health, Qingdao University, No. 308 Ningxia Road, Qingdao, 266071 Shandong Province China
| | - Wenqin Yao
- Department of Epidemiology and Health Statistics, School of Public Health, Qingdao University, No. 308 Ningxia Road, Qingdao, 266071 Shandong Province China
- Shandong Province Center for Disease Control and Prevention, Shandong, China
| | - Qihua Tan
- Epidemiology and Biostatistics, Department of Public Health, University of Southern Denmark, Odense, Denmark
| | - Shuxia Li
- Epidemiology and Biostatistics, Department of Public Health, University of Southern Denmark, Odense, Denmark
| | - Haiping Duan
- Qingdao Municipal Center for Disease Control and Prevention/Qingdao Institute of Preventive Medicine, Qingdao, Shandong China
| | - Xiaocao Tian
- Qingdao Municipal Center for Disease Control and Prevention/Qingdao Institute of Preventive Medicine, Qingdao, Shandong China
| | - Chunsheng Xu
- Qingdao Municipal Center for Disease Control and Prevention/Qingdao Institute of Preventive Medicine, Qingdao, Shandong China
| | - Dongfeng Zhang
- Department of Epidemiology and Health Statistics, School of Public Health, Qingdao University, No. 308 Ningxia Road, Qingdao, 266071 Shandong Province China
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9
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Juvinao-Quintero DL, Sharp GC, Sanderson ECM, Relton CL, Elliott HR. Investigating causality in the association between DNA methylation and type 2 diabetes using bidirectional two-sample Mendelian randomisation. Diabetologia 2023; 66:1247-1259. [PMID: 37202507 PMCID: PMC10244277 DOI: 10.1007/s00125-023-05914-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 01/25/2023] [Indexed: 05/20/2023]
Abstract
AIMS/HYPOTHESIS Several studies have identified associations between type 2 diabetes and DNA methylation (DNAm). However, the causal role of these associations remains unclear. This study aimed to provide evidence for a causal relationship between DNAm and type 2 diabetes. METHODS We used bidirectional two-sample Mendelian randomisation (2SMR) to evaluate causality at 58 CpG sites previously detected in a meta-analysis of epigenome-wide association studies (meta-EWAS) of prevalent type 2 diabetes in European populations. We retrieved genetic proxies for type 2 diabetes and DNAm from the largest genome-wide association study (GWAS) available. We also used data from the Avon Longitudinal Study of Parents and Children (ALSPAC, UK) when associations of interest were not available in the larger datasets. We identified 62 independent SNPs as proxies for type 2 diabetes, and 39 methylation quantitative trait loci as proxies for 30 of the 58 type 2 diabetes-related CpGs. We applied the Bonferroni correction for multiple testing and inferred causality based on p<0.001 for the type 2 diabetes to DNAm direction and p<0.002 for the opposing DNAm to type 2 diabetes direction in the 2SMR analysis. RESULTS We found strong evidence of a causal effect of DNAm at cg25536676 (DHCR24) on type 2 diabetes. An increase in transformed residuals of DNAm at this site was associated with a 43% (OR 1.43, 95% CI 1.15, 1.78, p=0.001) higher risk of type 2 diabetes. We inferred a likely causal direction for the remaining CpG sites assessed. In silico analyses showed that the CpGs analysed were enriched for expression quantitative trait methylation sites (eQTMs) and for specific traits, dependent on the direction of causality predicted by the 2SMR analysis. CONCLUSIONS/INTERPRETATION We identified one CpG mapping to a gene related to the metabolism of lipids (DHCR24) as a novel causal biomarker for risk of type 2 diabetes. CpGs within the same gene region have previously been associated with type 2 diabetes-related traits in observational studies (BMI, waist circumference, HDL-cholesterol, insulin) and in Mendelian randomisation analyses (LDL-cholesterol). Thus, we hypothesise that our candidate CpG in DHCR24 may be a causal mediator of the association between known modifiable risk factors and type 2 diabetes. Formal causal mediation analysis should be implemented to further validate this assumption.
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Affiliation(s)
- Diana L Juvinao-Quintero
- MRC Integrative Epidemiology Unit, Bristol Medical School, University of Bristol, Bristol, UK.
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK.
- Department of Epidemiology, Harvard T. H. Chan School of Public Health, Boston, MA, USA.
| | - Gemma C Sharp
- MRC Integrative Epidemiology Unit, Bristol Medical School, University of Bristol, Bristol, UK
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Eleanor C M Sanderson
- MRC Integrative Epidemiology Unit, Bristol Medical School, University of Bristol, Bristol, UK
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Caroline L Relton
- MRC Integrative Epidemiology Unit, Bristol Medical School, University of Bristol, Bristol, UK
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Hannah R Elliott
- MRC Integrative Epidemiology Unit, Bristol Medical School, University of Bristol, Bristol, UK.
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK.
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10
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Sandholm N, Dahlström EH, Groop PH. Genetic and epigenetic background of diabetic kidney disease. Front Endocrinol (Lausanne) 2023; 14:1163001. [PMID: 37324271 PMCID: PMC10262849 DOI: 10.3389/fendo.2023.1163001] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 05/10/2023] [Indexed: 06/17/2023] Open
Abstract
Diabetic kidney disease (DKD) is a severe diabetic complication that affects up to half of the individuals with diabetes. Elevated blood glucose levels are a key underlying cause of DKD, but DKD is a complex multifactorial disease, which takes years to develop. Family studies have shown that inherited factors also contribute to the risk of the disease. During the last decade, genome-wide association studies (GWASs) have emerged as a powerful tool to identify genetic risk factors for DKD. In recent years, the GWASs have acquired larger number of participants, leading to increased statistical power to detect more genetic risk factors. In addition, whole-exome and whole-genome sequencing studies are emerging, aiming to identify rare genetic risk factors for DKD, as well as epigenome-wide association studies, investigating DNA methylation in relation to DKD. This article aims to review the identified genetic and epigenetic risk factors for DKD.
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Affiliation(s)
- Niina Sandholm
- Folkhälsan Institute of Genetics, Folkhälsan Research Center, Helsinki, Finland
- Department of Nephrology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Emma H. Dahlström
- Folkhälsan Institute of Genetics, Folkhälsan Research Center, Helsinki, Finland
- Department of Nephrology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Per-Henrik Groop
- Folkhälsan Institute of Genetics, Folkhälsan Research Center, Helsinki, Finland
- Department of Nephrology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Department of Diabetes, Central Clinical School, Monash University, Melbourne, VIC, Australia
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11
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Su S, Ma Z, Wu H, Xu Z, Yi H. Oxidative stress as a culprit in diabetic kidney disease. Life Sci 2023; 322:121661. [PMID: 37028547 DOI: 10.1016/j.lfs.2023.121661] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 03/26/2023] [Accepted: 03/31/2023] [Indexed: 04/08/2023]
Abstract
Diabetic kidney disease (DKD) has become the leading cause of end-stage renal disease (ESRD), and the prevalence of DKD has increased worldwide during recent years. DKD is associated with poor therapeutic outcomes in most patients, but there is limited understanding of its pathogenesis. This review suggests that oxidative stress interacts with many other factors in causing DKD. Highly active mitochondria and NAD(P)H oxidase are major sources of oxidants, and they significantly affect the risk for DKD. Oxidative stress and inflammation may be considered reciprocal causes of DKD, in that each is a cause and an effect of DKD. Reactive oxygen species (ROS) can act as second messengers in various signaling pathways and as regulators of metabolism, activation, proliferation, differentiation, and apoptosis of immune cells. Epigenetic modifications, such as DNA methylation, histone modifications, and non-coding RNAs can modulate oxidative stress. The development of new technologies and identification of new epigenetic mechanisms may provide novel opportunities for the diagnosis and treatment of DKD. Clinical trials demonstrated that novel therapies which reduce oxidative stress can slow the progression of DKD. These therapies include the NRF2 activator bardoxolone methyl, new blood glucose-lowering drugs such as sodium-glucose cotransporter 2 inhibitors, and glucagon-like peptide-1 receptor agonists. Future studies should focus on improving early diagnosis and the development of more effective combination treatments for this multifactorial disease.
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Tang J, Tan M, Liao S, Pang M, Li J. Recent progress in the biology and physiology of BMP-8a. Connect Tissue Res 2023; 64:219-228. [PMID: 36594156 DOI: 10.1080/03008207.2022.2160326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
PURPOSE BMP-8a is a member of bone morphogenetic proteins (BMPs) and plays a regulatory role in human growth and development as a transcription regulator. This review aims to summarize the current research on the impact and mechanism of BMP-8a in female and male reproduction, formation and eruption of teeth, bone and cartilage development, tissue differentiation, disease occurrence, progression and prognosis. METHODS The phrases "BMP-8a," "BMPs," "regulator," "mechanism," "osteoblast," "cartilage," "cancer," "disease," and "inflammation" were searched in the PubMed database. The abstracts were evaluated, and a series of original publications and reviews were examined. RESULTS According to the search, BMP-8a affects the development of the uterus by inhibiting luteinization and plays an important role in late spermatogenesis. It is highly expressed in osteogenesis and differentially expressed in chondrogenesis. Furthermore, BMP-8a has a significant impact on the occurrence, development and prognosis of various diseases. CONCLUSIONS BMP-8a regulates important factors and pathways, such as SMAD2/3 and SMAD1/5/8, to promote or inhibit the developmental processes of human reproductive organs. BMP-8a is also a member of the BMP family of proteins that regulates chondrogenesis and osteogenesis. In addition to its osteoinductive capabilities, BMP-8a is involved in the progression of diverse cancers.
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Affiliation(s)
- Jiawei Tang
- College of Stomatology, Chongqing Medical University, Chongqing, China
| | - Miao Tan
- College of Stomatology, Chongqing Medical University, Chongqing, China
| | - Siqi Liao
- College of Stomatology, Chongqing Medical University, Chongqing, China
| | - Mengwei Pang
- College of Stomatology, Chongqing Medical University, Chongqing, China
| | - Jie Li
- College of Stomatology, Chongqing Medical University, Chongqing, China
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Miller RG, Mychaleckyj JC, Onengut-Gumuscu S, Orchard TJ, Costacou T. TXNIP DNA methylation is associated with glycemic control over 28 years in type 1 diabetes: findings from the Pittsburgh Epidemiology of Diabetes Complications (EDC) study. BMJ Open Diabetes Res Care 2023; 11:e003068. [PMID: 36604111 PMCID: PMC9827189 DOI: 10.1136/bmjdrc-2022-003068] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 12/21/2022] [Indexed: 01/07/2023] Open
Abstract
INTRODUCTION DNA methylation (DNAme) has been cross-sectionally associated with type 2 diabetes and hemoglobin A1c (HbA1c) in the general population. However, longitudinal data and data in type 1 diabetes are currently very limited. Thus, we performed an epigenome-wide association study (EWAS) in an observational type 1 diabetes cohort to identify loci with DNAme associated with concurrent and future HbA1cs, as well as other clinical risk factors, over 28 years. RESEARCH DESIGN AND METHODS Whole blood DNAme in 683 597 CpGs was analyzed in the Pittsburgh Epidemiology of Diabetes Complications study of childhood onset (<17 years) type 1 diabetes (n=411). An EWAS of DNAme beta values and concurrent HbA1c was performed using linear models adjusted for diabetes duration, sex, pack years of smoking, estimated cell type composition variables, and technical/batch covariates. A longitudinal EWAS of subsequent repeated HbA1c measures was performed using mixed models. We further identified methylation quantitative trait loci (meQTLs) for significant CpGs and conducted a Mendelian randomization. RESULTS DNAme at cg19693031 (Chr 1, Thioredoxin-Interacting Protein (TXNIP)) and cg21534330 (Chr 17, Casein Kinase 1 Isoform Delta) was significantly inversely associated with concurrent HbA1c. In longitudinal analyses, hypomethylation of cg19693031 was associated with consistently higher HbA1c over 28 years, and with higher triglycerides, pulse rate, and albumin:creatinine ratio (ACR) independently of HbA1c. We further identified 34 meQTLs in SLC2A1/SLC2A1-AS1 significantly associated with cg19693031 DNAme. CONCLUSIONS Our results extend prior findings that TXNIP hypomethylation relates to worse glycemic control in type 1 diabetes by demonstrating the association persists over the long term. Additionally, the associations with triglycerides, pulse rate, and ACR suggest TXNIP DNAme could play a role in vascular damage independent of HbA1c. These findings strengthen potential for interventions targeting TXNIP to improve glycemic control in type 1 diabetes through its role in SLC2A1/glucose transporter 1-mediated glucose regulation.
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Affiliation(s)
- Rachel G Miller
- Department of Epidemiology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Josyf C Mychaleckyj
- Center for Public Health Genomics, University of Virginia, Charlottesville, Virginia, USA
| | - Suna Onengut-Gumuscu
- Center for Public Health Genomics, University of Virginia, Charlottesville, Virginia, USA
| | - Trevor J Orchard
- Department of Epidemiology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Tina Costacou
- Department of Epidemiology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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Lu J, Liu X, Jiang S, Kan S, An Y, Zheng C, Li X, Liu Z, Xie G. Body Mass Index and Risk of Diabetic Nephropathy: A Mendelian Randomization Study. J Clin Endocrinol Metab 2022; 107:1599-1608. [PMID: 35191949 DOI: 10.1210/clinem/dgac057] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Indexed: 11/19/2022]
Abstract
CONTEXT The associations of obesity and diabetic nephropathy (DN) in type 2 diabetes are inconsistent in observational studies, and causality remains unclear. OBJECTIVE To explore the causal effect of body mass index (BMI) on DN, estimated glomerular filtration rate (eGFR), and proteinuria in type 2 diabetes by a 2-sample Mendelian randomization (MR) analysis. METHODS A total of 56 genetic variants were selected as instrumental variables for BMI in 158 284 participants from BioBank Japan, and their effects on DN risk, eGFR, and proteinuria were estimated in 3972 individuals with type 2 diabetes. Then, sex-stratified MR analysis was performed between BMI and DN. We selected generalized summary MR analysis as the primary method and 6 other robust methods to test MR assumptions. RESULTS One SD increase in BMI was causally associated with higher DN risk [odds ratio (OR) 3.76, 95% CI 1.88-7.53, P < 0.001] and lower eGFR level (OR 0.71, 95% CI 0.59-0.86, P < 0.001). However, BMI was not causally associated with proteinuria (P = 0.22). Sex-stratified analyses indicated the causal effect of BMI on DN was stronger in women (OR 14.81, 95% CI 2.67-82.05, P = 0.002) than in men (OR 3.48, 95% CI 1.18-10.27, P = 0.02). Sensitivity analyses did not show evidence for violation of the MR assumptions. CONCLUSIONS Genetic evidence showed that higher BMI levels were causally associated with increased risk of DN and decreased eGFR levels. Moreover, the increase in BMI level had a greater impact on DN risk in women.
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Affiliation(s)
- Jingru Lu
- School of Medicine, Southeast University, National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing, China
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | | | - Song Jiang
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Shuyan Kan
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Yu An
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Chunxia Zheng
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Xiang Li
- Ping An Healthcare Technology, Beijing, China
| | - Zhihong Liu
- School of Medicine, Southeast University, National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing, China
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Guotong Xie
- Ping An Healthcare Technology, Beijing, China
- Ping An Health Cloud Company Limited, Beijing, China
- Ping An International Smart City Technology Co., Ltd, Beijing, China
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Blood DNA Methylation Predicts Diabetic Kidney Disease Progression in High Fat Diet-Fed Mice. Nutrients 2022; 14:nu14040785. [PMID: 35215435 PMCID: PMC8880442 DOI: 10.3390/nu14040785] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 02/03/2022] [Accepted: 02/09/2022] [Indexed: 12/29/2022] Open
Abstract
Diabetic kidney disease (DKD) progresses at different rates among patients with type 2 diabetes mellitus (T2D). Early identification of patients with a higher risk of DKD progression is essential to improve prognosis. Epigenetic modifications, particularly DNA methylation, have been independently implicated in T2D and chronic kidney disease. The current study aimed to determine changes in blood DNA methylation that reflects and predicts DKD progression. C57BL/6 mice were fed a high-fat diet (HFD) from weaning and subclassified into two groups, HFD-1 and HFD-2, according to urinary kidney injury marker KIM-1/creatinine ratios (low vs. high) and histological abnormalities (mild–moderate vs. advanced). DNA methylation profiles were determined by reduced representative bisulfide sequencing (RRBS). Our results confirmed early and established DKD at week 9 and week 32, respectively. At week 32, advanced kidney injury was associated with dysregulation of methylation and demethylation enzymes in the kidney. Blood RRBS revealed 579 and 203 differentially methylated sites (DMS) between HFD-1 and HFD-2 animals at week 32 and week 9, respectively, among which 11 were common. The DMS in blood and kidney at week 32 were both related to organ development, neurogenesis, cell junction, and Wnt signalling, while the DMS in blood at week 9 suggested a specific enrichment of kidney development processes. In conclusion, our data strongly support the implication of early blood DNA methylation modifications and DKD progression in T2D that could be used to improve the disease’s prognostication.
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Walker-Short E, Buckner T, Vigers T, Carry P, Vanderlinden LA, Dong F, Johnson RK, Yang IV, Kechris K, Rewers M, Norris JM. Epigenome-Wide Association Study of Infant Feeding and DNA Methylation in Infancy and Childhood in a Population at Increased Risk for Type 1 Diabetes. Nutrients 2021; 13:4057. [PMID: 34836312 PMCID: PMC8618577 DOI: 10.3390/nu13114057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 11/05/2021] [Accepted: 11/08/2021] [Indexed: 12/16/2022] Open
Abstract
We assessed associations between infant diet (e.g., breastfeeding and introduction to solid foods) and DNA methylation in infancy and childhood. We measured DNA methylation in peripheral blood collected in infancy (9-15 months of age) in 243 children; and in a subset of 50 children, we also measured methylation in childhood (6-9 years of age) to examine persistence, and at birth (in cord blood) to examine temporality. We performed multivariable linear regression of infant diet on the outcome of methylation using epigenome-wide and candidate site approaches. We identified six novel CpG sites associated with breastfeeding duration using an EWAS approach. One differentially methylated site presented directionally consistent associations with breastfeeding (cg00574958, CPT1A) in infancy and childhood but not at birth. Two differentially methylated sites in infancy (cg19693031, TXNIP; cg23307264, KHSRP) were associated with breastfeeding and were not present at birth; however, these associations did not persist into childhood. Associations between infant diet and methylation in infancy at three sites (cg22369607, AP001525.1; cg2409200, TBCD; cg27173510, PGBD5) were also present at birth, suggesting the influence of exposures other than infant diet. Infant diet exposures are associated with persistent methylation differences in CPT1A, which may be one mechanism behind infant diet's long-term health effects.
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Affiliation(s)
- Elizabeth Walker-Short
- Department of Epidemiology, Colorado School of Public Health, Aurora, CO 80045, USA; (E.W.-S.); (T.B.); (P.C.); (L.A.V.); (R.K.J.); (I.V.Y.)
| | - Teresa Buckner
- Department of Epidemiology, Colorado School of Public Health, Aurora, CO 80045, USA; (E.W.-S.); (T.B.); (P.C.); (L.A.V.); (R.K.J.); (I.V.Y.)
| | - Timothy Vigers
- Department of Biostatistics and Informatics, Colorado School of Public Health, Aurora, CO 80045, USA; (T.V.); (K.K.)
- Barbara Davis Center for Diabetes, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; (F.D.); (M.R.)
| | - Patrick Carry
- Department of Epidemiology, Colorado School of Public Health, Aurora, CO 80045, USA; (E.W.-S.); (T.B.); (P.C.); (L.A.V.); (R.K.J.); (I.V.Y.)
| | - Lauren A. Vanderlinden
- Department of Epidemiology, Colorado School of Public Health, Aurora, CO 80045, USA; (E.W.-S.); (T.B.); (P.C.); (L.A.V.); (R.K.J.); (I.V.Y.)
| | - Fran Dong
- Barbara Davis Center for Diabetes, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; (F.D.); (M.R.)
| | - Randi K. Johnson
- Department of Epidemiology, Colorado School of Public Health, Aurora, CO 80045, USA; (E.W.-S.); (T.B.); (P.C.); (L.A.V.); (R.K.J.); (I.V.Y.)
- Division of Biomedical Informatics and Personalized Medicine, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Ivana V. Yang
- Department of Epidemiology, Colorado School of Public Health, Aurora, CO 80045, USA; (E.W.-S.); (T.B.); (P.C.); (L.A.V.); (R.K.J.); (I.V.Y.)
- Division of Biomedical Informatics and Personalized Medicine, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Katerina Kechris
- Department of Biostatistics and Informatics, Colorado School of Public Health, Aurora, CO 80045, USA; (T.V.); (K.K.)
| | - Marian Rewers
- Barbara Davis Center for Diabetes, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; (F.D.); (M.R.)
| | - Jill M. Norris
- Department of Epidemiology, Colorado School of Public Health, Aurora, CO 80045, USA; (E.W.-S.); (T.B.); (P.C.); (L.A.V.); (R.K.J.); (I.V.Y.)
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