Diabetes mellitus has become one of the most common chronic diseases, thereby posing a major challenge to global health. Characterized by high levels of blood glucose (hyperglycemia), diabetes usually results from a loss of insulin-producing β-cells in the pancreas, leading to a deficiency of insulin (type 1 diabetes), or loss of insulin sensitivity (type 2 diabetes). Both types of diabetes have serious secondary complications, such as microvascular abnormalities, cardiovascular dysfunction, and kidney failure. Various complex factors, such as genetic and environmental factors, are associated with the pathophysiology of diabetes. Over the past two decades, the role of small, single-stranded noncoding microRNAs in various metabolic disorders, especially diabetes mellitus and its complications, has gained widespread attention in the scientific community. Discovered first as an endogenous regulator of development in the nematode Caenorhabditis elegans, these small RNAs post-transcriptionally suppress mRNA target expression. In this review, we discuss the potential roles of different microRNAs in diabetes and diabetes-related complications.
Animals ; Diabetes Complications ; genetics ; metabolism ; Diabetes Mellitus ; genetics ; metabolism ; Glucose ; metabolism ; Homeostasis ; genetics ; Humans ; Insulin ; metabolism ; MicroRNAs ; biosynthesis ; genetics ; metabolism

The loss of or decreased functional pancreatic β-cell is a major cause of type 1 and type 2 diabetes. Previous studies have shown that adult β-cells can maintain their ability for a low level of turnover through replication and neogenesis. Thus, a strategy to prevent and treat diabetes would be to enhance the ability of β-cells to increase the mass of functional β-cells. Consequently, much effort has been devoted to identify factors that can effectively induce β-cell expansion. This review focuses on recent reports on small molecules and protein factors that have been shown to promote β-cell expansion.
Cell Communication ; genetics ; Cell Differentiation ; genetics ; Cell Proliferation ; Diabetes Mellitus, Type 1 ; genetics ; pathology ; Diabetes Mellitus, Type 2 ; genetics ; pathology ; Humans ; Insulin-Secreting Cells ; chemistry ; metabolism ; pathology

Gestational diabetes mellitus (GDM) is a growing public health problem worldwide that threatens both maternal and fetal health. Identifying individuals at high risk for GDM and diabetes after GDM is particularly useful for early intervention and prevention of disease progression. In the last decades, a number of studies have used metabolomics, genomics, and proteomic approaches to investigate associations between biomolecules and GDM progression. These studies clearly demonstrate that various biomarkers reflect pathological changes in GDM. The established markers have potential use as screening and diagnostic tools in GDM and in postpartum diabetes research. In the present review, we summarize recent studies of metabolites, single-nucleotide polymorphisms, microRNAs, and proteins associated with GDM and its transition to postpartum diabetes, with a focus on their predictive value in screening and diagnosis.
Pregnancy ; Female ; Humans ; Diabetes, Gestational/genetics* ; Proteomics ; Postpartum Period ; Biomarkers/metabolism* ; MicroRNAs/genetics* ; Diabetes Mellitus, Type 2

Type 2 diabetes mellitus is characterized by insulin resistance and failure of pancreatic beta-cells producing insulin. Autophagy plays a crucial role in cellular homeostasis through degradation and recycling of organelles such as mitochondria or endoplasmic reticulum (ER). Here we discussed the role of beta-cell autophagy in development of diabetes, based on our own studies using mice with beta-cell-specific deletion of Atg7 (autophagy-related 7), an important autophagy gene, and studies by others. beta-cell-specific Atg7-null mice showed reduction in beta-cell mass and pancreatic insulin content. Insulin secretory function ex vivo was also impaired, which might be related to organelle dysfunction associated with autophagy deficiency. As a result, beta-cell-specific Atg7-null mice showed hypoinsulinemia and hyperglycemia. However, diabetes never developed in those mice. Obesity and/or lipid are physiological ER stresses that can precipitate beta-cell dysfunction. Our recent studies showed that beta-cell-specific Atg7-null mice, when bred with ob/ob mice, indeed become diabetic. Thus, autophagy deficiency in beta-cells could be a precipitating factor in the progression from obesity to diabetes due to inappropriate response to obesity-induced ER stress.
Animals ; Autophagy/genetics/*physiology ; Diabetes Mellitus/genetics/*metabolism ; Endoplasmic Reticulum Stress/genetics/*physiology ; Humans ; Insulin-Secreting Cells/*metabolism

Aging ; genetics ; metabolism ; Animals ; Diabetes Mellitus ; enzymology ; metabolism ; Humans ; Longevity ; genetics ; physiology ; Neoplasms ; enzymology ; metabolism ; Neurodegenerative Diseases ; enzymology ; metabolism ; Obesity ; enzymology ; metabolism ; Sirtuins ; genetics ; metabolism

Post-translational modifications (PTMs) of transcription factors play a crucial role in regulating metabolic homeostasis. These modifications include phosphorylation, methylation, acetylation, ubiquitination, SUMOylation, and O-GlcNAcylation. Recent studies have shed light on the importance of lysine acetylation at nonhistone proteins including transcription factors. Acetylation of transcription factors affects subcellular distribution, DNA affinity, stability, transcriptional activity, and current investigations are aiming to further expand our understanding of the role of lysine acetylation of transcription factors. In this review, we summarize recent studies that provide new insights into the role of protein lysine-acetylation in the transcriptional regulation of metabolic homeostasis.
Acetylation ; Animals ; Diabetes Mellitus, Type 2 ; metabolism ; Homeostasis ; genetics ; physiology ; Humans ; Protein Processing, Post-Translational ; genetics ; physiology ; Transcription Factors ; metabolism

OBJECTIVEThe aim of this study is to determine whether the SUMO4 M55V polymorphism is associated with susceptibility to type 2 diabetes mellitus (T2DM).

METHODSA meta-analysis was performed to detect the potential association of the SUMO4 M55V polymorphism and susceptibility to T2DM under dominant, recessive, co-dominant (homogeneous and heterogeneous), and additive models.

RESULTSA total of eight articles including 10 case-control studies, with a total of 2932 cases and 2679 controls, were included in this meta-analysis. The significant association between the SUMO4 M55V polymorphism and susceptibility to T2DM was observed in the dominant model (GG + GA versus AA: OR = 1.21, 95% CI = 1.05-1.40, P = 0.009), recessive model (GG versus GA + AA: OR = 1.29, 95% CI = 1.07-1.356, P = 0.010), homozygous model (GG versus AA: OR = 1.41, 95% CI = 1.06-1.56, P = 0.001), and additive model (G versus A: OR = 1.18, 95% CI = 1.08-1.29, P = 0.001), and marginally significant in the heterozygous model (GA versus AA: OR = 1.16, 95% CI = 0.98-1.36, P = 0.080). In subgroup analyses, significant associations were observed in the Chinese population under four genetic models excluding the heterozygous model, whereas no statistically significant associations were observed in the Japanese population under each of the five genetic models.

CONCLUSIONThe meta-analysis demonstrated that the G allele of the SUMO4 M55V polymorphism could be a susceptible risk locus to T2DM, mainly in the Chinese population, while the association in other ethnic population needs to be further validated in studies with relatively large samples.

Diabetes Mellitus, Type 2 ; epidemiology ; genetics ; Genetic Predisposition to Disease ; epidemiology ; genetics ; Humans ; Small Ubiquitin-Related Modifier Proteins ; genetics ; metabolism

OBJECTIVETo study the role of plasminogen activator inhibitor-1 (PAI-1) and tissue plasminogen activator (tPA) in the accumulation of extracellular matrix (ECM) in the kidney of KKAy mice with type 2 diabetes.

METHODSKKAy mice, a type 2 diabetic animal model, and C57BL-J mice were sacrificed at 16, 20, and 24 weeks of age, respectively. The local expression of renal laminin was analyzed with immunohistochemistry. Chromogenic substance was used to show the activity of PAI-1. The mRNA expression of tPA was determined by RT-PCR. The mRNA expression of PAI-1 was measured by reverse transcription-polymerase chain reaction (RT-PCR).

RESULTSLaminnin expression was significantly increased in all age groups of KKAy mice. The tPA mRNA was significantly lower than that in C57BL mice, especially at the age of 16w (only 47%). Otherwise the PAI-1 mRNA expression was remarkably up-regulated than that in C57BL mice.

CONCLUSIONIn type 2 diabetes KKAy mice, the accumulation of ECM may be associated with the abnormal expression of PAI-1/tPA mRNA.

Animals ; Diabetes Mellitus, Experimental ; metabolism ; Diabetes Mellitus, Type 2 ; metabolism ; Extracellular Matrix ; metabolism ; Kidney ; metabolism ; Male ; Mice ; Mice, Inbred C57BL ; Plasminogen Activator Inhibitor 1 ; biosynthesis ; genetics ; RNA, Messenger ; biosynthesis ; genetics ; Tissue Plasminogen Activator ; biosynthesis ; genetics

OBJECTIVEThis review examines the evidence that: Diabetes is a state of DNA damage; pathophysiological factors in diabetes can cause DNA damage; DNA damage can cause mutations; and DNA mutation is linked to carcinogenesis.

DATA SOURCESWe retrieved information from the PubMed database up to January, 2014, using various search terms and their combinations including DNA damage, diabetes, cancer, high glucose, hyperglycemia, free fatty acids, palmitic acid, advanced glycation end products, mutation and carcinogenesis.

STUDY SELECTIONWe included data from peer-reviewed journals and a textbook printed in English on relationships between DNA damage and diabetes as well as pathophysiological factors in diabetes. Publications on relationships among DNA damage, mutagenesis, and carcinogenesis, were also reviewed. We organized this information into a conceptual framework to explain the possible causal relationship between DNA damage and carcinogenesis in diabetes.

RESULTSThere are a large amount of data supporting the view that DNA mutation is a typical feature in carcinogenesis. Patients with type 2 diabetes have increased production of reactive oxygen species, reduced levels of antioxidant capacity, and increased levels of DNA damage. The pathophysiological factors and metabolic milieu in diabetes can cause DNA damage such as DNA strand break and base modification (i.e., oxidation). Emerging experimental data suggest that signal pathways (i.e., Akt/tuberin) link diabetes to DNA damage. This collective evidence indicates that diabetes is a pathophysiological state of oxidative stress and DNA damage which can lead to various types of mutation to cause aberration in cells and thereby increased cancer risk.

CONCLUSIONSThis review highlights the interrelationships amongst diabetes, DNA damage, DNA mutation and carcinogenesis, which suggests that DNA damage can be a biological link between diabetes and cancer.

Animals ; DNA Damage ; genetics ; Diabetes Mellitus, Type 2 ; genetics ; metabolism ; Humans ; Neoplasms ; genetics ; metabolism ; Oxidative Stress ; genetics ; physiology ; Reactive Oxygen Species ; metabolism

Animals ; Carbon Radioisotopes ; Diabetes Mellitus, Experimental ; genetics ; metabolism ; Diabetes Mellitus, Type 1 ; genetics ; metabolism ; Gene Expression Regulation ; Glucose ; administration & dosage ; metabolism ; Lipid Metabolism ; Liver ; metabolism ; Male ; Mice ; Mice, Inbred C57BL ; Transcriptome