Comprehensive assessment of the association of WNK4 polymorphisms with hypertension: evidence from a meta-analysis

Screening and identification of key biomarkers associated with endometriosis using bioinformatics and next-generation sequencing data analysis

Background

Endometriosis is a common cause of endometrial-type mucosa outside the uterine cavity with symptoms such as painful periods, chronic pelvic pain, pain with intercourse and infertility. However, the early diagnosis of endometriosis is still restricted. The purpose of this investigation is to identify and validate the key biomarkers of endometriosis.

Methods

Next-generation sequencing dataset GSE243039 was obtained from the Gene Expression Omnibus database, and differentially expressed genes (DEGs) between endometriosis and normal control samples were identified. After screening of DEGs, gene ontology (GO) and REACTOME pathway enrichment analyses were performed. Furthermore, a protein–protein interaction (PPI) network was constructed and modules were analyzed using the Human Integrated Protein–Protein Interaction rEference database and Cytoscape software, and hub genes were identified. Subsequently, a network between miRNAs and hub genes, and network between TFs and hub genes were constructed using the miRNet and NetworkAnalyst tool, and possible key miRNAs and TFs were predicted. Finally, receiver operating characteristic curve analysis was used to validate the hub genes.

Results

A total of 958 DEGs, including 479 upregulated genes and 479 downregulated genes, were screened between endometriosis and normal control samples. GO and REACTOME pathway enrichment analyses of the 958 DEGs showed that they were mainly involved in multicellular organismal process, developmental process, signaling by GPCR and muscle contraction. Further analysis of the PPI network and modules identified 10 hub genes, including vcam1, snca, prkcb, adrb2, foxq1, mdfi, actbl2, prkd1, dapk1 and actc1. Possible target miRNAs, including hsa-mir-3143 and hsa-mir-2110, and target TFs, including tcf3 (transcription factor 3) and clock (clock circadian regulator), were predicted by constructing a miRNA-hub gene regulatory network and TF-hub gene regulatory network.

Conclusions

This investigation used bioinformatics techniques to explore the potential and novel biomarkers. These biomarkers might provide new ideas and methods for the early diagnosis, treatment and monitoring of endometriosis.

Cullin 3/with No Lysine [K] Kinase/Ste20/SPS-Related Proline Alanine Rich Kinase Signaling: Impact on NaCl Cotransporter Activity in BP Regulation

The sodium chloride cotransporter (NCC) fine-tunes Na + balance and indirectly affects the homeostasis of other ions including K + , Mg 2+ , and Ca 2+ . Owing to its effects on Na + balance, BP is significantly affected by alterations in NCC activity. Several factors have been reported to influence the expression and activity of NCC. One critical factor is NCC phosphorylation/dephosphorylation that occurs at key serine-threonine amino acid residues of the protein. Phosphorylation, which results in increased NCC activity, is mediated by the with no lysine [K] (WNK)-SPS-related proline alanine rich kinase (SPAK)/OSR1 kinases. NCC activation stimulates reabsorption of Na + , increasing extracellular fluid volume and hence BP. On the other hand, proteasomal degradation of WNK kinases after ubiquitination by the Cullin 3-Kelch-like 3 E3 ubiquitin ligase complex and dephosphorylation pathways oppose WNK-SPAK/OSR1-mediated NCC activation. Components of the Cullin 3/Kelch-like 3-WNK-SPAK/OSR1 regulatory pathway may be targets for novel antihypertensive drugs. In this review, we outline the impact of these regulators on the activity of NCC and the consequent effect on BP.

Ion homeostasis in diabetic kidney disease

The complications of type 2 diabetes are a major global public health problem with high incidence and mortality, affecting almost all individuals with diabetes worldwide. Diabetic kidney disease (DKD) is one such primary complication and has become a leading cause of end-stage renal disease in patients with diabetes. Progression from diabetes to DKD is a complex process typically involving multiple mechanisms. Recent remarkable clinical benefits of sodium-glucose cotransporter 2 (SGLT2) inhibitors in diabetes and DKD highlight the critical impact of renal ion homeostasis on disease progression. This review comprehensively examines the impact of ion homeostasis on the transition from diabetes to DKD, outlining possible therapeutic interventions and addressing the ongoing challenges in this rapidly developing field.

Regulatory control of the Na-Cl co-transporter NCC and its therapeutic potential for hypertension

Hypertension is the largest risk factor for cardiovascular disease, the leading cause of mortality worldwide. As blood pressure regulation is influenced by multiple physiological systems, hypertension cannot be attributed to a single identifiable etiology. Three decades of research into Mendelian forms of hypertension implicated alterations in the renal tubular sodium handling, particularly the distal convoluted tubule (DCT)-native, thiazide-sensitive Na-Cl cotransporter (NCC). Altered functions of the NCC have shown to have profound effects on blood pressure regulation as illustrated by the over activation and inactivation of the NCC in Gordon's and Gitelman syndromes respectively. Substantial progress has uncovered multiple factors that affect the expression and activity of the NCC. In particular, NCC activity is controlled by phosphorylation/dephosphorylation, and NCC expression is facilitated by glycosylation and negatively regulated by ubiquitination. Studies have even found parvalbumin to be an unexpected regulator of the NCC. In recent years, there have been considerable advances in our understanding of NCC control mechanisms, particularly via the pathway containing the with-no-lysine [K] (WNK) and its downstream target kinases, SPS/Ste20-related proline-alanine-rich kinase (SPAK) and oxidative stress responsive 1 (OSR1), which has led to the discovery of novel inhibitory molecules. This review summarizes the currently reported regulatory mechanisms of the NCC and discusses their potential as therapeutic targets for treating hypertension.

WNK-SPAK/OSR1-NCC kinase signaling pathway as a novel target for the treatment of salt-sensitive hypertension

Hypertension is the most prevalent health condition worldwide, affecting ~1 billion people. Gordon's syndrome is a form of secondary hypertension that can arise due to a number of possible mutations in key genes that encode proteins in a pathway containing the With No Lysine [K] (WNK) and its downstream target kinases, SPS/Ste20-related proline-alanine-rich kinase (SPAK) and oxidative stress responsive kinase 1 (OSR1). This pathway regulates the activity of the thiazide-sensitive sodium chloride cotransporter (NCC), which is responsible for NaCl reabsorption in the distal nephron. Therefore, mutations in genes encoding proteins that regulate the NCC proteins disrupt ion homeostasis and cause hypertension by increasing NaCl reabsorption. Thiazide diuretics are currently the main treatment option for Gordon's syndrome. However, they have a number of side effects, and chronic usage can lead to compensatory adaptations in the nephron that counteract their action. Therefore, recent research has focused on developing novel inhibitory molecules that inhibit components of the WNK-SPAK/OSR1-NCC pathway, thereby reducing NaCl reabsorption and restoring normal blood pressure. In this review we provide an overview of the currently reported molecular inhibitors of the WNK-SPAK/OSR1-NCC pathway and discuss their potential as treatment options for Gordon's syndrome.

Mechanisms and controversies in mutant Cul3-mediated familial hyperkalemic hypertension

Autosomal dominant mutations in cullin-3 ( Cul3) cause the most severe form of familial hyperkalemic hypertension (FHHt). Cul3 mutations cause skipping of exon 9, which results in an internal deletion of 57 amino acids from the CUL3 protein (CUL3-∆9). The precise mechanism by which this altered form of CUL3 causes FHHt is controversial. CUL3 is a member of the cullin-RING ubiquitin ligase family that mediates ubiquitination and thus degradation of cellular proteins, including with-no-lysine [K] kinases (WNKs). In CUL3-∆9-mediated FHHt, proteasomal degradation of WNKs is abrogated, leading to overactivation of the WNK targets sterile 20/SPS-1 related proline/alanine-rich kinase and oxidative stress-response kinase-1, which directly phosphorylate and activate the thiazide-sensitive Na⁺-Cl^- cotransporter. Several groups have suggested different mechanisms by which CUL3-∆9 causes FHHt. The majority of these are derived from in vitro data, but recently the Kurz group (Schumacher FR, Siew K, Zhang J, Johnson C, Wood N, Cleary SE, Al Maskari RS, Ferryman JT, Hardege I, Figg NL, Enchev R, Knebel A, O'Shaughnessy KM, Kurz T. EMBO Mol Med 7: 1285-1306, 2015) described the first mouse model of CUL3-∆9-mediated FHHt. Analysis of this model suggested that CUL3-∆9 is degraded in vivo, and thus Cul3 mutations cause FHHt by inducing haploinsufficiency. We recently directly tested this model but found that other dominant effects of CUL3-∆9 must contribute to the development of FHHt. In this review, we focus on our current knowledge of CUL3-∆9 action gained from in vitro and in vivo models that may help unravel this complex problem.

The CUL3/KLHL3-WNK-SPAK/OSR1 pathway as a target for antihypertensive therapy

Chronic high blood pressure (hypertension) is the most common disease in the Unites States. While several classes of drugs exist to treat it, many patients (up to 10 million Americans) respond poorly to therapy, even when multiple classes are used. Recent evidence suggests that a significant portion of patients will always remain hypertensive despite maximum therapy with the drugs currently available. Therefore, there is a pressing need to develop novel antihypertensive agents. One limitation has been the identification of new targets, a limitation that has been overcome by recent insights into the mechanisms underlying monogenic forms of hypertension. The disease familial hyperkalemic hypertension is caused by mutations in with-no-lysine (WNK) kinases 1 and 4 and in cullin-3 and kelch-like 3, components of an E3 ubiquitin ligase complex that promotes WNK kinase degradation. The study of the mechanisms by which this pathway regulates blood pressure has identified several candidates for the development of new antihypertensive agents. This pathway is particularly attractive since its inhibition may not only reduce renal sodium reabsorption along multiple segments but may also reduce vascular tone. Here, we will describe the mechanisms by which this pathway regulate blood pressure and discuss the potential of targeting it to develop new antihypertensive drugs.

Novel Association of WNK4 Gene, Ala589Ser Polymorphism in Essential Hypertension, and Type 2 Diabetes Mellitus in Malaysia

With-no-lysine (K) Kinase-4 (WNK4) consisted of unique serine and threonine protein kinases, genetically associated with an autosomal dominant form of hypertension. Argumentative consequences have lately arisen on the association of specific single nucleotide polymorphisms of WNK4 gene and essential hypertension (EHT). The aim of this study was to determine the association of Ala589Ser polymorphism of WNK4 gene with essential hypertensive patients in Malaysia. WNK4 gene polymorphism was specified utilizing mutagenically separated polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) method in 320 subjects including 163 cases and 157 controls. Close relation between Ala589Ser polymorphism and elevated systolic and diastolic blood pressure (SBP and DBP) was recognized. Sociodemographic factors including body mass index (BMI), age, the level of fasting blood sugar (FBS), low density lipoprotein (LDL), and triglyceride (TG) in the cases and healthy subjects exhibited strong differences (p < 0.05). The distribution of allele frequency and genotype of WNK4 gene Ala589Ser polymorphism showed significant differences (p < 0.05) between EHT subjects with or without type 2 diabetes mellitus (T2DM) and normotensive subjects, statistically. The WNK4 gene variation influences significantly blood pressure increase. Ala589Ser probably has effects on the enzymic activity leading to enhanced predisposition to the disorder.