The Finland–United States Investigation of Non–Insulin-Dependent Diabetes Mellitus Genetics (FUSION) Study. I. An Autosomal Genome Scan for Genes That Predispose to Type 2 Diabetes

Secretory Autophagy and Its Relevance in Metabolic and Degenerative Disease

Proteins to be secreted through so-called "conventional mechanisms" are characterized by the presence of an N-terminal peptide that is a leader or signal peptide, needed for access to the endoplasmic reticulum and the Golgi apparatus for further secretion. However, some relevant cytosolic proteins lack of this signal peptides and should be secreted by different unconventional or "non-canonical" processes. One form of this unconventional secretion was named secretory autophagy (SA) because it is specifically associated with the autophagy pathway. It is defined by ATG proteins that regulate the biogenesis of the autophagosome, its representative organelle. The canonical macroautophagy involves the fusion of the autophagosomes with lysosomes for content degradation, whereas the SA pathway bypasses this degradative process to allow the secretion. ATG5, as well as other factors involved in autophagy such as BCN1, are also activated as part of the secretory pathway. SA has been recognized as a new mechanism that is becoming of increasing relevance to explain the unconventional secretion of a series of cytosolic proteins that have critical biological importance. Also, SA may play a role in the release of aggregation-prone protein since it has been related to the autophagosome biogenesis machinery. SA requires the autophagic pathway and both, secretory autophagy and canonical degradative autophagy are at the same time, integrated and highly regulated processes that interact in ultimate cross-talking molecular mechanisms. The potential implications of alterations in SA, its cargos, pathways, and regulation in human diseases such as metabolic/aging pathological processes are predictable. Further research of SA as potential target of therapeutic intervention is deserved.

Association between type 2 diabetes mellitus, biochemical factors and UCSNP-43 polymorphisms of CALPIN-10 gene in patients with atherosclerosis of coronary artery disease in Southern Iran population

Introduction: Genetic variations in the calpain 10 gene (CALPIN-10), single nucleotide polymorphisms-43 (SNP-43), have increased the risk of type 2 diabete mellitus (T2DM) and coronary artery disease (CAD).

Methods: We studied the control and CAD groups for association of association of SNP-43 in the CALPIN-10 gene with T2DM and other risk factors of its complications. Overall, we examined 452 individuals, 224 patients with CAD and 228 healthy subjects for CAD in Iranian population. All the subjects were genotyped for the CALPIN-10, SNP-43 by polymorphism chain reaction (PCR) and restriction fragment length polymorphism (RFLP) methods, using biochemical methods to detect fasting glucose and other biochemical factors in the blood sample. We assessed frequencies of SNP-43 alleles between CAD and normal population groups.

Results: In CAD patients, the GG allele was significantly associated with T2DM and GG allele was causing high level of glucose. But in control group, there was no relationship between them. Between clinical and biochemical risk factors with different genotypes there was no significant difference in the compared group.

Conclusion: The results of our study suggest no significant association between SNP-43 and the risk of T2DM. In other words, CALPIN-10 did not show a major diabetes gene pool capacity in normal southern Iranian population.

Establishing the role of gene-environment interactions in the etiology of type 2 diabetes

The descriptive epidemiology of type 2 diabetes and findings from cohort studies suggest that this disorder originates in large part from a complex interaction between genetic and environmental factors. Determining the details of these interactions using the nested case-control design may be optimal, but is a long-term and expensive strategy. Quicker and cheaper results may be obtained by studying interaction on the quantitative traits that underlie diabetes; however, the power of such studies to detect interaction is highly dependent on the precision with which non-genetic exposures are measured. Unraveling these interactions will undoubtedly shed light on the etiology of diabetes and will, we hope, lead to opportunities for targeted prevention. Recent studies in high-risk groups such as people with impaired glucose tolerance suggest that the incidence of diabetes can be reduced by more than 50% by interventions aimed at changing dietary and physical activity behavior [39,40]; however, it may be that individuals with a particular genotype are particularly susceptible to the negative metabolic consequences of sedentary living, and that they conversely, therefore, would have most to gain from a targeted preventive intervention program. Understanding how to detect these individuals and which environmental factors a program should attempt to manipulate is a major goal of studies that attempt to unravel gene-environment interaction.