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BACKGROUND: Transcription factor 7-like 2 (TCF7L2), which previously known as TCF-4, is a major form of transcription factor involved in the downstream WNT signaling and exhibits the strongest association to diabetes susceptibility. Although we still do not know mechanistically how TCF7L2 exerts its physiological functions on pancreatic endocrine cells, it had been suggested that TCF7L2 may directly affect ß-cell function by regulating the activation of PI3K/AKT signaling pathway. METHODS: MIN6 cells were transfected with TCF7L2 knockdown virus or lenti-TCF7L2 virus for 48 h to evaluate the contribution of TCF7L2 to the PI3K/AKT signaling pathway and pancreatic ß-cell function. This was confirmed by measuring the expression of PI3K p85 and p-Akt by western blotting and insulin secretion by enzyme-linked immunosorbent assay (ELISA), respectively. Chromatin immunoprecipitation (ChIP) and polymerase chain reaction (PCR) experiments were performed to explore the genomic distribution of TCF7L2-binding sites in the promoter of PIK3R1, the affinity between which was analyzed by the luciferase reporter assay. RESULTS: In the present study, we strikingly identified that TCF7L2 could profoundly inhibit the expression of PIK3R1 gene and its encoding protein PI3K p85, which then could lead to the activation of PI3K/AKT signaling and stimulate insulin secretion in pancreatic ß-cells. However, the integrity and stability of evolutionarily conserved TCF7L2-binding motif plays a very crucial role in the binding events between transcription factor TCF7L2 and its candidate target genes. We also found that the affinity of TCF7L2 to the promoter region of PIK3R1 alters upon the specific binding sites, which further provides statistical validation to the necessity of TCF7L2-binding motif. CONCLUSIONS: This study demonstrated that TCF7L2 is closely bound to the specific binding regions of PIK3R1 promoter and prominently controls the transcription of its encoding protein p85, which further affects the activation of PI3K/AKT signaling pathway and insulin secretion.

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AIM: To identify the contribution of CDKAL1 to the development of diabetic retinopathy (DR) in Chinese population. METHODS: A case-control study was performed to investigate the genetic association between DR and polymorphic variants of CDKAL1 in Chinese Han population with type 2 diabetes mellitus (T2DM). A well-defined population with T2DM, consisting of 475 controls and 105 DR patients, was recruited. All subjects were genotyped for the genetic variant (rs10946398) of CDKAL1. Genotyping was performed by iPLEX technology. The association between rs10946398 and T2DM was assessed by univariate and multivariate logistic regression (MLR) analysis. RESULTS: There were significant differences in C allele frequencies of rs10946398 (CDKAL1) between control and DR groups (45.06% versus 55.00%, P<0.05). The rs10946398 of CDKAL1 was found to be associated with the increased risk of DR among patients with diabetes. CONCLUSION: Our findings suggest that rs10946398 of CDKAL1 is independently associated with DR in a Chinese Han population.

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BACKGROUND: The purpose of this study was to evaluate the associations of excess weight (EW) and/or chronic kidney disease (CKD) with cardiovascular autonomic neuropathy (CAN), and to detect the extent to which interaction of EW and CKD has on the outcome in a Chinese sample. METHOD: We conducted a large-scale, population-based study to analyze the association and interaction of the two factors on CAN in a sample of 2092 Chinese people. Multiple linear regression analysis to include the two main factors and its interaction were employed to detect these relationships. Relative excess risk due to interaction (RERI), the proportion attributable to interaction (AP) and the synergy index (S) were used to estimate the effect of interaction on an additive scale can. RESULT: Multivariable logistic regression (MLR) indicated that body mass index (BMI) was independently associated with CAN (p = 0.006). In addition, a significant positive interaction between BMI and CKD on CAN was estimated (p = 0.042, RETI = 0.473, 95% CI: 0.0615-0.884, AP = 0.203, 95% CI: -0.055 to 0.461 and S = 1.550, 95% CI: 0.667-2.589). CONCLUSION: Our findings suggest that BMI is independently associated with CAN and offer evidence to support the hypothesis that excess weight and CKD have significant positive interactions on CAN.

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BACKGROUND: The objective of this study was to evaluate associations of metabolic syndrome (MetS) and chronic kidney disease (CKD) with cardiovascular autonomic neuropathy (CAN), and to estimate the extent to which interaction of MetS and CKD affects the outcome in the Chinese population. METHOD: We conducted a large-scale, population-based study to analyze the association and interaction of the two factors for CAN in a sample of 2,092 Chinese people. Univariate and multiple linear regression (MLR) analysis were employed to detect these relationships. Interaction on an additive scale can be calculated by using the relative excess risk due to interaction (RERI), the proportion attributable to interaction (AP), and the synergy index (S). RESULTS: MLR adjusted for confounding factors showed that MetS was independently associated with CAN (P < 0.001). A significant interaction effect was detected by MLR (P = 0.042). In addition, a positive interaction between MetS and CKD on CAN was estimated by using parameters of RETI = 0.119 (95% CI: 0.059-0.178), AP = 0.049 (95% CI: -0.039-0.138) and S = 1.091 (95% CI: 0.164-2.019). CONCLUSION: Our findings suggest that MetS is independently associated with CAN and offer evidence to support the hypothesis that MetS and CKD have positive interactions on CAN.

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BACKGROUND: Genome-wide association studies (GWAS) have reported that the polymorphism rs5219 of the potassium inwardly rectifying channel, subfamily J, member 11 (KCNJ11) is associated with type 2 diabetes mellitus (T2DM). Given that diabetic retinopathy (DR) is one of the most common microvascular complications of T2DM, GWAS have identified a number of potential susceptibility genes for DR. However, only a fraction of them have been replicated in different studies and show consistent genetic associations with the occurrence of DR. The aim of the present study was to investigate whether common variants of KCNJ11 confer DR in a cohort of the Chinese Han population. METHODS: A case-control study of 580 T2DM patients, including 105 T2DM with DR and 475 T2DM without DR was performed. A single nucleotide polymorphism (SNP) of KCNJ11 (rs5219) was genotyped, and its association with DR was explored using a dominant genetic model. Genotyping was performed by iPLEX technology. Univariate and multivariate logistic regression (MLR) analysis controlling for confounders was conducted to evaluate the association between rs5219 and DR. RESULTS: The A allele frequency of rs5219 was significantly higher in DR patients than that in the patients without DR (49.01% versus 38.68%, P <0.05). We found the minor A allele could increase the risk to develop DR (ORint = 1.58, 95% CI: 1.139 to 2.192 for allele and P = 0.006, ORint =1.607, 95% CI: 1.267 to 2.038 for genotype and P <0.001) in the Chinese Han population. CONCLUSIONS: Our findings provided evidence that KCNJ11 was associated with DR in Chinese Han patients with T2DM.

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BACKGROUND: Peroxisome proliferator-activated receptor gamma coactivator-1α (PPARGC1A/ PGC-1α) is a ligand-activated transcription factor belonging to the nuclear hormone receptor superfamily. The activity of PGC-1α or genetic variations in the gene encoding the enzyme may contribute to individual variations in mitochondrial function and insulin resistance or diabetes. The objective of this study was to assess the extent to which PPARGC1A (rs8192678) and serum uric acid (UA) and its interaction impact on T2DM susceptibility in Chinese Han population. METHOD: We conducted a study in a cohort that included 1166 T2DM patients and 1135 controls, and was genotyped for the presence of the PPARGC1A rs8192678 polymorphisms. Genotyping was performed by iPLEX technology. The association between rs8192678 or UA and T2DM was assessed by univariate and multivariate logistic regression (MLR) analysis controlling for confounders. The interaction between rs8192678 and UA for T2DM susceptibility was also assessed by MLR analysis. RESULTS: The generalized linear regression analysis failed to show an association between the PPARGC1A rs8192678 polymorphisms and T2DM. Interestingly, the present study provided data suggesting that the minor A-allele of PPARGC1A (rs8192678) had a protective effect against T2DM in subjects with higher level of UA (ORint =1.50 95% CI: 1.06-2.12 for allele and P = 0.02, ORint =1.63 95% CI: 1.17-2.26 for genotype and P = 0.004). CONCLUSION: The combination of higher level of UA and PPARGC1A (rs8192678) was an independent predictor for T2DM.

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BACKGROUND: The objective of this study was to systematically evaluate the contribution of the insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) to type 2 diabetes mellitus (T2DM) and its interaction with obesity to T2DM susceptibility. METHODS: To clarify whether IGF2BP2 is an independent risk factor for T2DM in Chinese population, we conducted a study with a total of 2,301 Chinese Han subjects, including 1,166 T2DM patients and 1,135 controls, for the genotype of a most common and widely studied polymorphism-rs4402960 of IGF2BP2. Genotyping was performed by iPLEX technology. Gene and environment interaction analysis was performed by using multiple logistic regression models. RESULTS: The repeatedly confirmed association between IGF2BP2 (rs4402960) and T2DM had not been replicated in this cohort (P = 0.182). Interestingly, we found that obese subjects (body mass index (BMI) ≥ 28.0 kg/m2) bearing the minor A allele had an increased risk to develop T2DM (P = 0.008 for allele analysis and P < 0.001 for genotype analysis). CONCLUSIONS: The present study provided data suggesting that the wild C allele of IGF2BP2 (rs4402960) had a protective effect against T2DM in obese subjects of Chinese Han population.

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During Bacillus subtilis sporulation, SpoIIIE is required for translocation of the trapped forespore chromosome across the sporulation septum, for compartmentalization of cell-specific gene expression, and for membrane fusion after engulfment. We isolated mutations within the SpoIIIE membrane domain that block localization and function. One mutant protein initially localizes normally and completes DNA translocation, but shows reduced membrane fusion after engulfment. Fluorescence recovery after photobleaching experiments demonstrate that in this mutant the sporulation septum remains open, allowing cytoplasmic contents to diffuse between daughter cells, suggesting that it blocks membrane fusion after cytokinesis as well as after engulfment. We propose that SpoIIIE catalyses these topologically opposite fusion events by assembling or disassembling a proteinaceous fusion pore. Mutants defective in SpoIIIE assembly also demonstrate that the ability of SpoIIIE to provide a diffusion barrier is directly proportional to its ability to assemble a focus at the septal midpoint during DNA translocation. Thus, SpoIIIE mediates compartmentalization by two distinct mechanisms: the SpoIIIE focus first provides a temporary diffusion barrier during DNA translocation, and then mediates the completion of membrane fusion after division to provide a permanent diffusion barrier. SpoIIIE-like proteins might therefore serve to couple the final step in cytokinesis, septal membrane fusion, to the completion of chromosome segregation.

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