A Common Tag Nucleotide Variant in MMP7 Promoter Increases Risk for Hypertension via Enhanced Interactions With CREB (Cyclic AMP Response Element-Binding Protein) Transcription Factor

Genetic and Epigenetic Mechanisms Regulating Blood Pressure and Kidney Dysfunction

The pioneering work of Dr Lewis K. Dahl established a relationship between kidney, salt, and high blood pressure (BP), which led to the major genetic-based experimental model of hypertension. BP, a heritable quantitative trait affected by numerous biological and environmental stimuli, is a major cause of morbidity and mortality worldwide and is considered to be a primary modifiable factor in renal, cardiovascular, and cerebrovascular diseases. Genome-wide association studies have identified monogenic and polygenic variants affecting BP in humans. Single nucleotide polymorphisms identified in genome-wide association studies have quantified the heritability of BP and the effect of genetics on hypertensive phenotype. Changes in the transcriptional program of genes may represent consequential determinants of BP, so understanding the mechanisms of the disease process has become a priority in the field. At the molecular level, the onset of hypertension is associated with reprogramming of gene expression influenced by epigenomics. This review highlights the specific genetic variants, mutations, and epigenetic factors associated with high BP and how these mechanisms affect the regulation of hypertension and kidney dysfunction.

Cellular senescence is associated with the spatial evolution toward a higher metastatic phenotype in colorectal cancer

In this study, we explore the dynamic process of colorectal cancer progression, emphasizing the evolution toward a more metastatic phenotype. The term "evolution" as used in this study specifically denotes the phenotypic transition toward a higher metastatic potency from well-formed glandular structures to collective invasion, ultimately resulting in the development of cancer cell buddings at the invasive front. Our findings highlight the spatial correlation of this evolution with tumor cell senescence, revealing distinct types of senescent tumor cells (types I and II) that play different roles in the overall cancer progression. Type I senescent tumor cells (p16INK4A+/CXCL12+/LAMC2-/MMP7-) are identified in the collective invasion region, whereas type II senescent tumor cells (p16INK4A+/CXCL12+/LAMC2+/MMP7+), representing the final evolved form, are prominently located in the partial-EMT region. Importantly, type II senescent tumor cells associate with local invasion and lymph node metastasis in colorectal cancer, potentially affecting patient prognosis.

A common Matrix metalloproteinase 8 promoter haplotype enhances the risk for hypertension via diminished interactions with nuclear factor kappa B

OBJECTIVES

Matrix metalloproteinase 8 (MMP8) has a prominent role in collagen turnover in blood vessels and vascular remodeling. The contribution of regulatory single nucleotide polymorphisms in MMP8 to cardiovascular diseases is unclear. We aimed to delineate the influence of MMP8 promoter variations on hypertension.

METHODS

A case-control study in unrelated individuals ( n  = 2565) was carried out. Resequencing of the MMP8 proximal promoter, linkage disequilibrium analysis, genotyping of variants and regression analyses were performed. MMP8 promoter-reporter constructs were generated and expressed in human vascular endothelial cells under various conditions.

RESULTS

We identified four single nucleotide polymorphisms (SNPs) in the promoter region of MMP8 : -1089A/G (rs17099452), -815G/T (rs17099451), -795C/T (rs11225395), -763A/T (rs35308160); these SNPs form three major haplotypes. Hap3 (viz., GTTT haplotype) carriers showed significant associations with hypertension in two geographically distinct human populations (e.g., Chennai: odds ratio [OR] = 1.47, 95% confidence interval [CI] = 1.16-1.86, P  = 2 × 10 -3 ; Chandigarh: OR = 1.85, 95% CI = 1.21-2.81, P  = 4 × 10 -3 ). Hap3 carriers also displayed elevated systolic blood pressure, diastolic blood pressure and mean arterial pressure levels. Hap3 promoter-reporter construct showed lower promoter activity than the wild-type (Hap1) construct. In silico analysis and molecular dynamics studies predicted diminished binding of the transcription factor nuclear factor kappa B (NF-κB) to the functional -815T allele of Hap3 compared to the -815G wild-type allele; this prediction was validated by in-vitro experiments. Hap3 displayed impaired response to tumor necrosis factor-alpha treatment, possibly due to weaker binding of NF-κB. Notably, MMP8 promoter haplotypes were identified as independent predictors of plasma MMP8 and endothelial dysfunction markers (von Willebrand factor and endothelin-1) levels.

CONCLUSION

MMP8 promoter GTTT haplotype has a functional role in reducing MMP8 expression during inflammation via diminished interaction with NF-κB and in enhancing the risk of hypertension.

Design and synthesis of amino acid derivatives of substituted benzimidazoles and pyrazoles as Sirt1 inhibitors

Owing to its presence in several biological processes, Sirt1 acts as a potential therapeutic target for many diseases. Here, we report the structure-based designing and synthesis of two distinct series of novel Sirt1 inhibitors, benzimidazole mono-peptides and amino-acid derived 5-pyrazolyl methylidene rhodanine carboxylic acid. The compounds were evaluated for in vitro enzyme-based and cell-based Sirt1 inhibition assay, and cytotoxic-activity in both liver and breast cancer cells. The tryptophan conjugates i.e.13h (IC₅₀ = 0.66 μM, ΔG_bind = −1.1 kcal mol⁻¹) and 7d (IC₅₀ = 0.77 μM, ΔG_bind = −4.4 kcal mol⁻¹) demonstrated the maximum efficacy to inhibit Sirt1. The MD simulation unveiled that electrostatic complementarity at the substrate-binding-site through a novel motif “SLxVxP(V/F)A” could be a cause of increased Sirt1 inhibition by 13h and 13l over Sirt2 in cell-based assay, as compared to the control Ex527 and 7d. Finally, this study highlights novel molecules 7d and 13h, along with a new key hot-spot in Sirt1, which could be used as a starting lead to design more potent and selective sirtuin inhibitors as a potential anticancer molecule.

Owing to its presence in several biological processes, Sirt1 acts as a potential therapeutic target for many diseases.

Genetic Variants in Transcription Factor Binding Sites in Humans: Triggered by Natural Selection and Triggers of Diseases

Variants of transcription factor binding sites (TFBSs) constitute an important part of the human genome. Current evidence demonstrates close links between nucleotides within TFBSs and gene expression. There are multiple pathways through which genomic sequences located in TFBSs regulate gene expression, and recent genome-wide association studies have shown the biological significance of TFBS variation in human phenotypes. However, numerous challenges remain in the study of TFBS polymorphisms. This article aims to cover the current state of understanding as regards the genomic features of TFBSs and TFBS variants; the mechanisms through which TFBS variants regulate gene expression; the approaches to studying the effects of nucleotide changes that create or disrupt TFBSs; the challenges faced in studies of TFBS sequence variations; the effects of natural selection on collections of TFBSs; in addition to the insights gained from the study of TFBS alleles related to gout, its associated comorbidities (increased body mass index, chronic kidney disease, diabetes, dyslipidemia, coronary artery disease, ischemic heart disease, hypertension, hyperuricemia, osteoporosis, and prostate cancer), and the treatment responses of patients.