Recent Advances and Perspectives on the Use of Mineralocorticoid Receptor Antagonists for the Treatment of Hypertension and Chronic Kidney Disease: A Review.

Chronic kidney disease (CKD) is a major public health concern around the world. It is a significant risk factor for cardiovascular disease (CVD), and, as it progresses, the risk of cardiovascular events increases. Furthermore, end-stage kidney disease severely affects life expectancy and quality of life.

Effect of Haemodiafiltration Versus Haemodialysis on Vascular Access Patency when Starting Haemodialysis.

Background: Haemodiafiltration (HDF) therapy improves the prognosis by reducing inflammation and oxidative stress, and improving endothelial function. These factors contribute to vascular access (VA) stenosis, one of the most common complications in patients on haemodialysis (HD) or HDF. This study aimed to assess the efficacy of HDF on VA patency.

Familial Hyperkalemic Hypertension.

The rare disease Familial Hyperkalemic Hypertension (FHHt) is caused by mutations in the genes encoding Cullin 3 (CUL3), Kelch-Like 3 (KLHL3), and two members of the With-No-Lysine [K] (WNK) kinase family, WNK1 and WNK4. In the kidney, these mutations ultimately cause hyperactivation of NCC along the renal distal convoluted tubule. Hypertension results from increased NaCl retention, and hyperkalemia by impaired K secretion by downstream nephron segments.

Successful treatment of severe renal failure caused by malignant hypertension using a combination of renin-angiotensin-aldosterone system inhibitors: a case report.

Marked activation of the renin-angiotensin-aldosterone system (RAAS) plays an important role in malignant hypertension (MHT) by worsening hypertension and renal function. The rates of readmission for severe hypertension and cardiovascular disease in such emergencies are high, suggesting that suppression of the RAAS may be inadequate during the acute phase in some cases. This report presents a case of MHT complicated with renal insufficiency (creatinine 3.

Enriched Single-Nucleus RNA-Sequencing Reveals Unique Attributes of Distal Convoluted Tubule Cells.

Significance Statement: High-resolution single-nucleus RNA-sequencing data indicate a clear separation between primary sites of calcium and magnesium handling within distal convoluted tubule (DCT). Both DCT1 and DCT2 express Slc12a3, but these subsegments serve distinctive functions, with more abundant magnesium-handling genes along DCT1 and more calcium-handling genes along DCT2. The data also provide insight into the plasticity of the distal nephron-collecting duct junction, formed from cells of separate embryonic origins.

Dysregulation of the WNK4-SPAK/OSR1 pathway has a minor effect on baseline NKCC2 phosphorylation.

The with-no-lysine kinase 4 (WNK4)-sterile 20/SPS-1-related proline/alanine-rich kinase (SPAK)/oxidative stress-responsive kinase 1 (OSR1) pathway mediates activating phosphorylation of the furosemide-sensitive Na-K-2Cl cotransporter (NKCC2) and the thiazide-sensitive NaCl cotransporter (NCC). The commonly used pT96/pT101-pNKCC2 antibody cross-reacts with pT53-NCC in mice on the C57BL/6 background due to a five amino acid deletion. We generated a new C57BL/6-specific pNKCC2 antibody (anti-pT96-NKCC2) and tested the hypothesis that the WNK4-SPAK/OSR1 pathway strongly regulates the phosphorylation of NCC but not NKCC2.

Renal effects of cullin 3 mutations causing familial hyperkalemic hypertension.

Purpose Of Review: Mutations in the E3 ubiquitin ligase scaffold cullin 3 (CUL3) cause the disease familial hyperkalemic hypertension (FHHt) by hyperactivating the NaCl cotransporter (NCC). The effects of these mutations are complex and still being unraveled. This review discusses recent findings revealing the molecular mechanisms underlying the effects of CUL3 mutations in the kidney.

Cullin 3 and Blood Pressure Regulation: Insights From Familial Hyperkalemic Hypertension.

The study of rare monogenic forms of hypertension has led to the elucidation of important physiological pathways controlling blood pressure. Mutations in several genes cause familial hyperkalemic hypertension (also known as Gordon syndrome or pseudohypoaldosteronism type II). The most severe form of familial hyperkalemic hypertension is caused by mutations in , encoding CUL3 (Cullin 3)-a scaffold protein in an E3 ubiquitin ligase complex that tags substrates for proteasomal degradation.

Cullin 3 mutant causing familial hyperkalemic hypertension lacks normal activity in the kidney.

Mutations in the ubiquitin ligase scaffold protein cullin 3 (CUL3) cause the disease familial hyperkalemic hypertension (FHHt). We recently reported that in the kidney, aberrant mutant CUL3 (CUL3-Δ9) activity lowers the abundance of CUL3-Δ9 and Kelch-like 3, the CUL3 substrate adaptor for with-no-lysine kinase 4 (WNK4) and that this is mechanistically important. However, whether CUL3-Δ9 exerts additional effects on other targets that may alter renal function is unclear.

A case of ALG11-congenital disorders of glycosylation diagnosed by post-mortem whole exome sequencing.

Introduction: Congenital disorders of glycosylation (CDG) are inherited inborn errors of metabolism due to abnormal protein and lipid glycosylation that present with multi-systemic manifestations. The heterogeneity of CDG poses a serious diagnostic challenge; therefore, whole-exome sequencing (WES), which plays an increasingly important role in the molecular diagnosis of CDG, is used for examining patients with CDG.

Case Report: We report the case of a two-month-old male patient who developed developmental and epileptic encephalopathy (DEE) with intractable seizures and microcephaly.

Maintenance therapy for long-term control of high-grade endometrial stromal sarcoma.

High-grade endometrial stromal sarcoma (HG-ESS) is a malignant uterine tumour with a poor prognosis. This study aimed to demonstrate the usefulness of maintenance chemotherapy with paclitaxel (PTX) and carboplatin (CBDCA) for HG-ESS recurrence, by examining a case of HG-ESS tumour progression as a result of maintenance therapy interruption because of the COVID-19 pandemic. The patient was a woman in her 60s who presented with lower abdominal pain, nausea and a pelvic tumour, which was diagnosed as HG-ESS.

Mineralocorticoid Receptor Antagonists Cause Natriuresis in the Absence of Aldosterone.

Background: MR (mineralocorticoid receptor) antagonists are recommended for patients with resistant hypertension even when circulating aldosterone levels are not high. Although aldosterone activates MR to increase epithelial sodium channel (ENaC) activity, glucocorticoids also activate MR but are metabolized by 11βHSD2 (11β-hydroxysteroid dehydrogenase type 2). 11βHSD2 is expressed at increasing levels from distal convoluted tubule (DCT) through collecting duct.

Combined Kelch-like 3 and Cullin 3 Degradation is a Central Mechanism in Familial Hyperkalemic Hypertension in Mice.

Background: Mutations in the ubiquitin ligase scaffold protein Cullin 3 () gene cause the disease familial hyperkalemic hypertension (FHHt). In the kidney, mutant () increases abundance of With-No-Lysine (K) Kinase 4 (WNK4), inappropriately activating sterile 20/SPS-1-related proline/alanine-rich kinase (SPAK), which then phosphorylates and hyperactivates the NaCl cotransporter (NCC). The precise mechanism by which causes FHHt is unclear.

Klotho overexpression protects against renal aging along with suppression of transforming growth factor-β1 signaling pathways.

Klotho is an antiaging protein reported to suppress transforming growth factor-β1 (TGF-β1) signaling. Aging kidneys are characterized by interstitial fibrosis, accumulation of cell cycle-arrested cells, and increased levels of oxidative stress. TGF-β1 signaling is involved in these processes.

Molecular Mechanisms of Renal Magnesium Reabsorption.

Magnesium is an essential cofactor in many cellular processes, and aberrations in magnesium homeostasis can have life-threatening consequences. The kidney plays a central role in maintaining serum magnesium within a narrow range (0.70-1.

NaCl cotransporter activity and Mg handling by the distal convoluted tubule.

The genetic disease Gitelman syndrome, knockout mice, and pharmacological blockade with thiazide diuretics have revealed that reduced activity of the NaCl cotransporter (NCC) promotes renal Mg wasting. NCC is expressed along the distal convoluted tubule (DCT), and its activity determines Mg entry into DCT cells through transient receptor potential channel subfamily M member 6 (TRPM6). Several other genetic forms of hypomagnesemia lower the drive for Mg entry by inhibiting activity of basolateral Na-K-ATPase, and reduced NCC activity may do the same.

A case report of adult-onset COQ8B nephropathy presenting focal segmental glomerulosclerosis with granular swollen podocytes.

Background: Primary coenzyme Q10 (CoQ10) deficiency of genetic origin is one of a few treatable focal segmental glomerulosclerosis (FSGS). Renal morphologic evidence for COQ8B mutation and CoQ10 deficiencies of other gene mutations is assessed using electron microscopy with marked increase of abnormal-shaped mitochondria in podocytes. However, light microscopic morphologic features of deficiencies other than FSGS have not been reported.

Renal medullary tonicity regulates RNF183 expression in the collecting ducts via NFAT5.

Nuclear factor of activated T-cells 5 (NFAT5) directly binds to the promoter of the RING finger protein 183 (RNF183) gene and induces its transcription under hypertonic conditions in mouse inner-medullary collecting duct (mIMCD-3) cells. However, there is no specific anti-RNF183 antibody for immunostaining; therefore, it is unclear whether NFAT5 regulates RNF183 expression in vivo and where RNF183 is localized in the kidney. This study investigated NFAT5-regulated in vivo RNF183 expression and localization using CRISPR/Cas9-mediated RNF183-green fluorescent protein (RNF183-GFP) knock-in mice.

NFAT5 up-regulates expression of the kidney-specific ubiquitin ligase gene under hypertonic conditions in inner-medullary collecting duct cells.

We previously reported that among the 37 RING finger protein (RNF) family members, mRNA is specifically expressed in the kidney under normal conditions. However, the mechanism supporting its kidney-specific expression pattern remains unclear. In this study, we elucidated the mechanism of the transcriptional activation of murine in inner-medullary collecting duct cells.

Sec16A, a key protein in COPII vesicle formation, regulates the stability and localization of the novel ubiquitin ligase RNF183.

We identified 37 ubiquitin ligases containing RING-finger and transmembrane domains. Of these, we found that RNF183 is abundantly expressed in the kidney. RNF183 predominantly localizes to the endoplasmic reticulum (ER), Golgi, and lysosome.

Seasonal variation in hemodialysis initiation: A single-center retrospective analysis.

The number of new dialysis patients has been increasing worldwide, particularly among elderly individuals. However, information on seasonal variation in hemodialysis initiation in recent decades is lacking, and the seasonal distribution of patients' conditions immediately prior to starting dialysis remains unclear. Having this information could help in developing a modifiable approach to improving pre-dialysis care.