The TRIB3 Q84R polymorphism, insulin resistance and related metabolic alterations

Investigation of common risk factors between polycystic ovary syndrome and Alzheimer's disease: a narrative review

BACKGROUND

The most common endocrine and metabolic disorders in premenopausal women is polycystic ovary syndrome (PCOS), characterized by hyperandrogenism, chronic anovulation, and/or ultrasound evidence of small ovarian cysts. Obesity and insulin resistance are also the main factors influencing the clinical manifestations of this syndrome. Alzheimer's disease (AD) is the most typical progressive neurodegenerative disorder of the brain, and recent studies suggest a relationship between endocrinal dysregulation and neuronal loss during AD pathology.

AIM

This study aimed to evaluate the common risk factors for Alzheimer's and PCOS based on previous studies. Knowing the common risk factors and eliminating them may prevent neurodegenerative Alzheimer's disease in the future.

METHOD

In this narrative review, international databases, including Google Scholar, Scopus, PubMed, and the Web of Science, were searched to retrieve the relevant studies. The relevant studies' summaries were categorized to discuss the possible pathways that may explain the association between Alzheimer's and PCOS signs/symptoms and complications.

RESULTS

According to our research, the factors involved in Alzheimer's and PCOS disorders may share some common risk factors. In patients with PCOS, increased LH to FSH ratio, decreased vitamin D, insulin resistance, and obesity are some of the most important factors that may increase the risk of Alzheimer's disease.

TRIB3 rs6037475 is a potential biomarker for predicting felodipine drug response in Chinese patients with hypertension

Background

Our previous studies have found that single nucleotide polymorphisms (SNPs) of tribbles homolog 3 (TRIB3) are related to the hypotensive effects of calcium-channel blockers (CCBs) and angiotensin-converting enzyme (ACE) inhibitors. In this study, we aimed at exploring and validating the effect of TRIB3 polymorphism on antihypertensive drugs responses.

Methods

A total of 830 hypertensive patients, who were administered with open-labeled hydrochlorothiazide (12.5 mg once daily) and randomly assigned to off-labeled felodipine (5 mg) or a matched placebo combination treatment (1:1), were selected from the Felodipine Event Reduction (FEVER) study. A strategy of screening 259 samples and validating the remaining 531 samples was implemented. Four functional SNPs were selected (rs2295490, rs11470129, rs4815567 and rs6037475 in TRIB3). A mixed linear model was performed to analyze the effects of TRIB3 SNPs on antihypertensive drugs responses.

Results

We found that TRIB3 rs6037475 CC genotype was associated with a reduction of diastolic blood pressure (DBP) (P=6.3×10⁻³) in the felodipine treatment group of screening set, and was also associated with a reduction of systolic blood pressure (SBP) (P=0.021), DBP (P=6.0×10⁻³) and mean arterial pressure (MAP) (P=0.021) in the felodipine treatment group of the validation set. As for the reductions influenced by the rs2295490, rs11470129 and rs4815567 genetic variations, however, the adjusted P-value did not reach statistical significance. Combined screening and validation set analysis found that patients with TRIB3 rs6037475 CC genotype had a significant higher mean SBP, DBP and MAP than those with TT genotype in the felodipine treatment group (CC vs. TT −10.2±0.74 vs. −17.8±0.21, P=7.8×10⁻³; −4.6±0.50 vs. −10.2±0.23, P=3.0×10⁻⁴; −6.5±0.54 vs. −12.7±0.14, P=3.0×10⁻⁴, respectively).

Conclusions

These results suggest that TRIB3 rs6037475 genetic variation can be useful as a bio-marker for predicting felodipine drug response in Chinese patients with hypertension.

Polytropic Influence of TRIB3 rs2295490 Genetic Polymorphism on Response to Antihypertensive Agents in Patients With Essential Hypertension

Tribbles homolog 3 (TRIB3) mediating signaling pathways are closely related to blood pressure regulation. Our previous findings suggested a greater benefit on vascular outcomes in patients carrying TRIB3 (251, A > G, rs2295490) G allele with good glucose and blood pressure control. And TRIB3 (rs2295490) AG/GG genotypes were found to reduce primary vascular events in type 2 diabetic patients who received intensive glucose treatment as compared to those receiving standard glucose treatment. However, the effect of TRIB3 genetic variation on antihypertensives was not clear in essential hypertension patients. A total of 368 patients treated with conventional dosage of antihypertensives (6 groups, grouped by atenolol/bisoprolol, celiprolol, doxazosin, azelnidipine/nitrendipine, imidapril, and candesartan/irbesartan) were enrolled in our study. Genetic variations were successfully identified by sanger sequencing. A linear mixed model analysis was performed to evaluate blood pressures among TRIB3 (251, A > G) genotypes and adjusted for baseline age, gender, body mass index, systolic blood pressure (SBP), diastolic blood pressure (DBP), total cholesterol and other biochemical factors appropriately. Our data suggested that TRIB3 (251, A > G) AA genotype carriers showed better antihypertensive effect than the AG/GG genotype carriers [P = 0.014 for DBP and P = 0.042 for mean arterial pressure (MAP)], with a maximal reduction of DBP by 4.2 mmHg and MAP by 3.56 mmHg after azelnidipine or nitrendipine treatment at the 4th week. Similar tendency of DBP-change and MAP-change was found for imidapril (ACEI) treatment, in which marginally significances were achieved (P = 0.073 and 0.075, respectively). Against that, we found that TRIB3 (251, A > G) AG/GG genotype carriers benefited from antihypertensive therapy of ARBs with a larger DBP-change during the period of observation (P = 0.036). Additionally, stratified analysis revealed an obvious difference of the maximal blood pressure change (13 mmHg for the MAP between male and female patients with AA genotype who took ARBs). Although no significant difference in antihypertensive effect between TRIB3 (251, A > G) genotypes in patients treated with α, β-ADRs was observed, we found significant difference in age-, sex-dependent manner related to α, β-ADRs. In conclusion, our data supported that TRIB3 (251, A > G) genetic polymorphism may serve as a useful biomarker in the treatment of hypertension.

Interaction of germline variants in a family with a history of early-onset clear cell renal cell carcinoma

Background

Identification of genetic factors causing predisposition to renal cell carcinoma has helped improve screening, early detection, and patient survival.

Methods

We report the characterization of a proband with renal and thyroid cancers and a family history of renal and other cancers by whole‐exome sequencing (WES), coupled with WES analysis of germline DNA from additional affected and unaffected family members.

Results

This work identified multiple predicted protein‐damaging variants relevant to the pattern of inherited cancer risk. Among these, the proband and an affected brother each had a heterozygous Ala45Thr variant in SDHA, a component of the succinate dehydrogenase (SDH) complex. SDH defects are associated with mitochondrial disorders and risk for various cancers; immunochemical analysis indicated loss of SDHB protein expression in the patient’s tumor, compatible with SDH deficiency. Integrated analysis of public databases and structural predictions indicated that the two affected individuals also had additional variants in genes including TGFB2, TRAP1, PARP1, and EGF, each potentially relevant to cancer risk alone or in conjunction with the SDHA variant. In addition, allelic imbalances of PARP1 and TGFB2 were detected in the tumor of the proband.

Conclusion

Together, these data suggest the possibility of risk associated with interaction of two or more variants.

A Drosophila model of insulin resistance associated with the human TRIB3 Q/R polymorphism

Members of the Tribbles family of proteins are conserved pseudokinases with diverse roles in cell growth and proliferation. Both Drosophila Tribbles (Trbl) and vertebrate Trib3 proteins bind to the kinase Akt (Akt1) to block its phosphorylation activation and reduce downstream insulin-stimulated anabolism. A single nucleotide polymorphism (SNP) variant in human TRIB3, which results in a glutamine (Q) to arginine (R) missense mutation in a conserved motif at position 84, confers stronger Akt binding, resulting in reduced Akt phosphorylation, and is associated with a predisposition to Type 2 diabetes, cardiovascular disease, diabetic nephropathy, chronic kidney disease and leukemogenesis. Here, we used a Drosophila model to understand the importance of the conserved R residue in several Trbl functions. In the fly fat body, misexpression of a site-directed Q mutation at position R141 resulted in weakened binding to Drosophila Akt (dAkt), leading to increased levels of phospho-dAkt, increased cell and tissue size, and increases in the levels of stored glycogen and triglycerides. Consistent with the functional conservation of this arginine in modulating Akt activity, mouse Trib3 R84 misexpressed in the fly fat body blocked dAkt phosphorylation with a strength similar to wild-type Trbl. Limited mutational analysis shows that the R141 site dictates the strength of Akt binding but does not affect other Trbl-dependent developmental processes, suggesting a specificity that could serve as a drug target for metabolic diseases.

Governing roles for Trib3 pseudokinase during stress erythropoiesis

In response to anemia, the heightened production of erythropoietin (EPO) can sharply promote erythroid progenitor cell (EPC) formation. Specific mediators of such EPO- accelerated erythropoiesis, however, are not well understood. Presently, we first report that the expression of Trib3 in adult bone marrow EPCs in vivo is nominal at steady state, but strongly activated on EPO challenge. In a knockout mouse model, Trib3 disruption modestly increased steady-state erythrocyte numbers and decreased mean corpuscular volume. Following 5-fluorouracil myeloablation, however, rebound red blood cell production and hemoglobin levels were substantially (and selectively) compromised in Trib3^-/- mice versus Trib3^+/+ congenic controls. Erythrocytes from 5-fluorouracil-treated Trib3^-/- mice additionally were more prone to lysis and exhibited elevated peroxide-induced reactive oxygen species. Ex vivo, the development of CD71^posTer119^pos erythroblasts from Trib3^-/- bone marrow progenitors was attenuated, and this was associated with heightened EPO-dependent Erk1/2 activation and moderately increased Akt activation. For developmentally staged EPCs, gene profiling provided further initial insight into candidate mediators of EPO-induced Trib3 gene expression, including Cebp-beta, Atf4, Egr-1, and Nab1. Overall, Trib3 is indicated to act as a novel EPC-intrinsic governor of stress erythropoiesis.