Collectrin, an X-linked, angiotensin converting enzyme 2 homolog, causes hypertension in a rat strain through gene-gene and gene-environment interactions: relevance to human hypertension

Heteromeric Solute Carriers: Function, Structure, Pathology and Pharmacology

Solute carriers form one of three major superfamilies of membrane transporters in humans, and include uniporters, exchangers and symporters. Following several decades of molecular characterisation, multiple solute carriers that form obligatory heteromers with unrelated subunits are emerging as a distinctive principle of membrane transporter assembly. Here we comprehensively review experimentally established heteromeric solute carriers: SLC3-SLC7 amino acid exchangers, SLC16 monocarboxylate/H⁺ symporters and basigin/embigin, SLC4A1 (AE1) and glycophorin A exchanger, SLC51 heteromer Ost α-Ost β uniporter, and SLC6 heteromeric symporters. The review covers the history of the heteromer discovery, transporter physiology, structure, disease associations and pharmacology - all with a focus on the heteromeric assembly. The cellular locations, requirements for complex formation, and the functional role of dimerization are extensively detailed, including analysis of the first complete heteromer structures, the SLC7-SLC3 family transporters LAT1-4F2hc, b^0,+AT-rBAT and the SLC6 family heteromer B⁰AT1-ACE2. We present a systematic analysis of the structural and functional aspects of heteromeric solute carriers and conclude with common principles of their functional roles and structural architecture.

Hypermethylation of dihydrofolate reductase promoter increases the risk of hypertension in Chinese

Background:

DNA methylation was considered to play an important role in hypertension. However, the direct association between dihydrofolate reductase (DHFR) promoter methylation and hypertension remains unclear. We thus aimed to investigate the relationship between DNA methylation of DHFR promoter and hypertension.

Materials and Methods:

A total of 371 hypertensive patients (diastolic blood pressure ≥90 mmHg and/or systolic blood pressure ≥140 mmHg or a history of antihypertensive treatment) and 320 age- and sex-matched healthy controls from the Hypertension Management Information System in Nanshan Community Health Service Centers were included in this case–control study. Quantitative methylation-specific polymerase chain reaction was used to measure the level of DHFR promoter methylation, which was presented as the percentage of methylated reference (PMR). A multivariate logistic regression model was used to explore the risk of DHFR promoter methylation.

Results:

Our results indicated that the level of DHFR promoter methylation was higher in hypertensive patients (median PMR, 34.32%; interquartile range, 11.34–119.60) than in healthy controls (median PMR, 18.45%; interquartile range, 8.16–35.40) (P < 0.001). Multivariable analysis showed that the risk of DHFR promoter hypermethylation was significantly higher in hypertensive patients than in healthy controls (odds ratio = 3.94, 95% confidence interval = 2.56–6.02, P < 0.001). Furthermore, hypermethylation was positively associated with sex, high blood homocysteine levels, and alcohol drinking. In particular, the area under the receiver operating characteristic curve was 0.688 (0.585–0.668) for the male hypertensive patients, suggesting the potential diagnostic value of DHFR promoter methylation in male hypertension.

Conclusion:

Our results demonstrated that DHFR promoter hypermethylation is positively associated with the risk of hypertension in Chinese.

Molecular Aspects of COVID-19 Differential Pathogenesis

In the absence of therapeutic interventions, and a possible vaccine candidate, the spread of COVID-19 disease and associated fatalities are on the rise. The high mutation frequency in the genomic material of these viruses supports their ability to adapt to new environments, resulting in an efficient alteration in tissue tropism and host range. Therefore, the coronavirus' health threats could be relevant for the long-term. The epidemiological data indicate that age, sex, and cardio-metabolic disease have a significant impact on the spread and severity of COVID-19. In this review, we highlight recent updates on the pathogenesis of SARS-CoV-2 among men and women, including children. We also discuss the role of the cellular receptors and coreceptors used by the virus to enter host cells on differential infection among men, women, and cardio-metabolic patients.

CBS promoter hypermethylation increases the risk of hypertension and stroke

OBJECTIVES

Cystathionine β-synthase is a major enzyme in the metabolism of plasma homocysteine. Hyperhomocysteinemia is positively associated with hypertension and stroke. The present study was performed to examine the possible effects of Cystathionine β-synthase promoter methylation on the development of hypertension and stroke.

METHODS

Using quantitative methylation-specific PCR, we determined the Cystathionine β-synthase methylation levels in 218 healthy individuals and 132 and 243 age- and gender-matched stroke and hypertensive patients, respectively. The relative changes in Cystathionine β-synthase promoter methylation were analyzed using the 2-ΔΔCt method. The percent of the methylated reference of Cystathionine β-synthase was used to represent the Cystathionine β-synthase promoter methylation levels.

RESULTS

In this study, the Cystathionine β-synthase promoter methylation levels of hypertensive and stroke participants were both higher than that of the healthy individuals (median percentages of the methylated reference were 50.61%, 38.05% and 30.53%, respectively, all p<0.001). Multivariable analysis showed that Cystathionine β-synthase promoter hypermethylation increased the risk of hypertension [odds ratio, OR (95% confidence interval, CI)=1.035 (1.025-1.045)] and stroke [OR (95% CI)=1.015 (1.003-1.028)]. The area under the curve of Cystathionine β-synthase promoter methylation was 0.844 (95% CI: 0.796-0.892) in male patients with hypertension and 0.722 (95% CI: 0.653-0.799) in male patients with stroke.

CONCLUSION

Cystathionine β-synthase promoter hypermethylation increases the risk of hypertension and stroke, especially in male patients.

Molecular basis for the interaction of the mammalian amino acid transporters B0AT1 and B0AT3 with their ancillary protein collectrin

Many solute carrier 6 (SLC6) family transporters require ancillary subunits to modify their expression and activity. The main apical membrane neutral amino acid transporters in mouse intestine and kidney, B(0)AT1 and B(0)AT3, require the ancillary protein collectrin or ACE2 for plasma membrane expression. Expression and activity of SLC6 neurotransmitter transporters are modulated by interaction with syntaxin 1A. Utilizing monocarboxylate-B(0)AT1/3 fusion constructs, we discovered that collectrin is also necessary for B(0)AT1 and B(0)AT3 catalytic function. Syntaxin 1A and syntaxin 3 inhibit the membrane expression of B(0)AT1 by competing with collectrin for access. A mutagenesis screening approach identified residues on trans-membrane domains 1α, 5, and 7 on one face of B(0)AT3 as a key region involved in interaction with collectrin. Mutant analysis established residues that were involved in collectrin-dependent functions as follows: plasma membrane expression of B(0)AT3, catalytic activation, or both. These results identify a potential binding site for collectrin and other SLC6 ancillary proteins.