Body mass index and acid phosphatase locus 1 in diabetic disorders

A genome-wide association study identifies novel candidate genes for susceptibility to diabetes mellitus in non-obese cats

Diabetes mellitus (DM) is a common feline endocrinopathy, which is similar to human type 2 diabetes (T2DM) in terms of its pathophysiology. T2DM occurs due to peripheral insulin resistance and/or β-cell dysfunction. Several studies have identified genetic and environmental factors that contribute to susceptibility to human T2DM. In cats, environmental factors such as obesity and physical inactivity have been linked with DM, although to date, the only genetic association that has been demonstrated is with a polymorphism in the feline MC4R gene. The aim of this study was to perform a genome-wide association study (GWAS) to identify polymorphisms associated with feline DM. Illumina Infinium 63k iSelect DNA arrays were used to analyse genomic DNA samples from 200 diabetic domestic shorthair cats and 399 non-diabetic control cats. Data was analysed using PLINK whole genome data analysis toolset. A linear model analysis, EMMAX, was done to test for population structure and HAPLOVIEW was used to identify haplotype blocks surrounding the significant SNPs to assist with candidate gene nomination. A total of 47,497 SNPs were available for analysis. Four SNPs were identified with genome-wide significance: chrA2.4150731 (p_raw = 9.94 x10^-8); chrUn17.115508 (p_raw = 6.51 x10^-8); chrUn17.394136 (p_raw = 2.53 x10^-8); chrUn17.314128 (p_raw = 2.53 x10^-8) as being associated with DM. The first SNP is located within chromosome A2, less than 4kb upstream of the dipeptidyl-peptidase-9 (DPP9) gene, a peptidase involved in incretin inactivation. The remaining three SNPs are located within a haplotype block towards the end of chromosome A3; within this region, genes of interest include TMEM18 and ACP1, both previously associated with T2DM. This study indicates a polygenic component to susceptibility to DM in cats and has highlighted several loci and candidate genes worthy of further investigation.

Low molecular weight protein tyrosine phosphatase (LMW-PTP2) protein can potentially modulate virulence of the parasite Entamoeba histolytica

The Entamoeba histolytica parasite is the causative agent of amebiasis, infecting approximately 1% of the world population and causing 100,000 deaths per year. It binds to Fibronectin (FN), activating signaling pathways regulated by kinases and phosphatases. EhLMW-PTPs genes from E. histolytica encode for Low Molecular Weight Tyrosine Phosphatases expressed in trophozoites and amoebic cysts. The role of these phosphatases in the virulence of the parasite has not yet been well characterized. Our results showed a differential expression of the EhLMW-PTPs, at the mRNA and protein levels, in an asynchronous trophozoites culture. Furthermore, we observed that trophozoites transfected that overexpressed EhLMW-PTP2 phagocytized fewer erythrocytes, possibly due to decreased phagocytic cups, and showed deficiencies in adherence to FN and less cytopathic effect. These analyzes suggest that the parasite's EhLMW-PTPs have an essential role in the mechanisms of proliferation, adhesion, and phagocytosis, regulating its pathogenicity.

Inhibition of Low Molecular Weight Protein Tyrosine Phosphatase by an Induced-Fit Mechanism

The low molecular weight protein tyrosine phosphatase (LMW-PTP) is a regulator of a number of signaling pathways and has been implicated as a potential target for oncology and diabetes/obesity. There is significant therapeutic interest in developing potent and selective inhibitors to control LMW-PTP activity. We report the discovery of a novel class of LMW-PTP inhibitors derived from sulfophenyl acetic amide (SPAA), some of which exhibit greater than 50-fold preference for LMW-PTP over a large panel of PTPs. X-ray crystallography reveals that binding of SPAA-based inhibitors induces a striking conformational change in the LMW-PTP active site, leading to the formation of a previously undisclosed hydrophobic pocket to accommodate the α-phenyl ring in the ligand. This induced-fit mechanism is likely a major contributor responsible for the exquisite inhibitor selectivity.

Body mass index is more strongly associated with hypertension than waist circumference in apparently healthy Japanese men and women

Obesity is associated with hypertension. However, it is controversial which obesity index, body mass index (BMI) or waist circumference (WC), is more strongly associated with hypertension. We compared the cross-sectional associations of BMI and WC with hypertension. Logistic regressions using hypertension as a dependent variable and age, BMI, WC, fasting plasma glucose, triglycerides, high-density lipoprotein cholesterol, smoking status, drinking status, and physical activity as independent variables were performed using data from apparently healthy 1,803 Japanese men aged 49.9 ± 9.0 and 1,150 women aged 49.5 ± 9.0 excluding subjects with a history of cardiovascular disease, or with antidiabetic, antihypertensive and/or antihyperlipidemic medications. The odds ratio [95% confidence interval] of 1 kg/m² increase in BMI and that of 1 cm increase in WC for diagnosing hypertension were 1.23 [1.11-1.36] (p < 0.0001) and 0.99 [0.95-1.02] (p = 0.4) in men and 1.35 [1.16-1.58] (p < 0.0001) and 0.97 [0.91-1.03] (p = 0.4) in women, respectively. Thus, BMI, but not WC, was independently associated with hypertension in apparently healthy Japanese men and women.