Novel Lipid Biomarkers of Chronic Kidney Disease of Unknown Etiology Based on Urinary Small Extracellular Vesicles: A Pilot Study of Sugar Cane Workers.

Background/objectives: Chronic kidney disease of unknown etiology (CKDu) disproportionately affects young male agricultural workers who are otherwise healthy. There is a scarcity of biomarkers for early detection of this type of kidney disease. We hypothesized that small extracellular vesicles (sEVs) released into urine may provide novel biomarkers.

Apoptosis, ferroptosis, necrosis, necroptosis and pyroptosis in the formation of calcium oxalate kidney stones.

Kidney stones are one of the most common and debilitating urological disorders, putting substantial financial burden on healthcare services. Most common kidney stones are comprised of calcium oxalate often mixed with some calcium phosphate. Pathogenesis involves crystallization and retention of crystals within the kidneys, which is achieved either through the formation of crystalline plugs in the terminal collecting ducts blocking their openings into the renal pelvis, or formation of plaques of calcium phosphate on the renal papillary surface.

Administration of Purified Alpha-1 Antitrypsin in Salt-Loaded Hypertensive 129Sv Mice Attenuates the Expression of Inflammatory Associated Proteins in the Kidney.

Background: Alpha-1 antitrypsin (AAT) is a multifunctional protease inhibitor that has been shown to have anti-inflammatory properties in various diseases. AAT has been reported to protect against renal injury via anti-apoptotic, anti-fibrotic, and anti-inflammatory effects. However, its role in mitigating renal inflammation and reducing high blood pressure induced by salt-loading has never been studied.

Fatty Acids and Inflammatory Protein Biomarkers From Coronavirus Disease 2019 Patients.

Background: The coronavirus disease 2019 (COVID-19) is a viral infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and associated with systemic inflammation. Inflammation is an important process that follows infection and facilitates the body's innate immune response and repair of damaged tissue. Polyunsaturated fatty acids play an important role in the inflammatory process.

Physiological role and mechanisms of action for a long noncoding haplotype region.

Direct targeting of noncoding genomic regions harboring common sequence variants associated with human traits through in vivo animal model studies and precise genome editing in human cells is essential for closing the critical gap between genetic discoveries and physiological understanding. However, such investigation has been impractical for many of these variants as they are in haplotypes containing multiple single-nucleotide polymorphisms (SNPs) spanning thousands of base pairs and have small effect sizes. We developed an integrated approach to address this challenge, combining an efficient two-step technique to precisely edit large haplotypes in human induced pluripotent stem cells and orthologous region deletion in phenotypically permissive animal models.

Small Extracellular Vesicles with a High Sphingomyelin Content Isolated from Hypertensive Diabetic db/db Mice Inhibits Calcium Mobilization and Augments Amiloride-Sensitive Epithelial Sodium Channel Activity.

Extracellular vesicles (EVs) contain bioactive lipids that play a key role in pathophysiology. We hypothesized that EVs released from salt-loaded hypertensive diabetic db/db mice have increased bioactive lipid content that inhibits intracellular calcium mobilization and increases the activity of renal epithelial sodium channels (ENaC). An enrichment of sphingomyelins (SMs) was found in small urinary EVs (uEVs) isolated from salt-loaded hypertensive diabetic db/db mice ( = 4) compared to non-salt loaded db/db mice with diabetes alone ( = 4).

Dapagliflozin Treatment Attenuates the Interaction between the Renal Sodium Chloride Co-Transporter and Ezrin in Hypertensive Diabetic db/db Mice.

Introduction: Ezrin is a protein that links the actin cytoskeleton to membrane proteins. The sodium chloride cotransporter (NCC) plays a key role in regulating total body electrolyte homeostasis and systemic blood pressure. Dapagliflozin, an SGLT2 inhibitor, is used to manage type 2 diabetes mellitus.

Activity and function of the endothelial sodium channel is regulated by the effector domain of MARCKS-like protein 1 in mouse aortic endothelial cells.

Enhanced endothelial sodium channel (EnNaC) functioning causes an increase in vessel stiffness. Here, we investigated the regulation of EnNaC in mouse aortic endothelial cells (mAoECs) by the actin cytoskeleton and lipid raft association protein myristoylated alanine-rich C-kinase substrate-like protein 1 (MLP1). We hypothesized that mutation of specific amino acid residues within the effector domain of MLP1 or loss of association between MLP1 and the anionic phospholipid phosphate PIP2 would significantly alter membrane association and EnNaC activity in mAoECs.

Alpha 1-antitrypsin mitigates salt-sensitive hypertension in juvenile mice by reducing diacylglycerol concentrations and protein kinase C activity in kidney membranes.

Introduction: Recombinant alpha-1 antitrypsin (AAT) therapy has been shown to have beneficial effects to mitigate the progression of various diseases. Here, we hypothesized that administration of pharmaceutical-grade human AAT (hAAT) is effective in mitigating hypertension induced by salt-loading in juvenile mice by reducing the concentration of diacylglycerols (DAGs) and activity of protein kinase C (PKC) in the kidney.

Methods: Four-week old 129Sv mice were salt-loaded to induce hypertension and then administered hAAT or vehicle.

Activity of Various Cathepsin Proteases and Enrichment of Klotho Protein in the Urine and Urinary Extracellular Vesicles After SARS-CoV-2 Infection.

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is responsible for causing the Coronavirus disease 2019 (COVID-19) outbreak. While mutations cause the emergence of new variants, the ancestral SARS-CoV-2 strain is unique among other strains. Various clinical parameters, the activity of cathepsin proteases, and the concentration of various proteins were measured in urine samples from COVID-19-negative participants and COVID-19-positive participants.

Physiological role and mechanisms of action for a long noncoding haplotype region.

Most common sequence variants associated with human traits are in noncoding regions of the genome, form haplotypes with other noncoding variants, and exhibit small effect sizes in the general population. Determining the physiological roles and mechanisms of action for these noncoding variants, particularly large haplotypes containing multiple variants, is both critical and challenging. To address this challenge, we developed an approach that integrates physiological studies in genetically engineered and phenotypically permissive animal models, precise editing of large haplotypes in human induced pluripotent stem cells (hiPSCs), and targeted chromatin conformation analysis.

Activity and function of the endothelial sodium channel is regulated by the effector domain of MARCKS like protein 1 in mouse aortic endothelial cells.

The endothelial sodium channel (EnNaC) plays an important role in regulating vessel stiffness. Here, we investigated the regulation of EnNaC in mouse aortic endothelial cells (mAoEC) by the actin cytoskeleton and lipid raft association protein myristoylated alanine-rich C-kinase substrate like protein 1 (MLP1). We hypothesized that mutation of specific amino acid residues within the effector domain of MLP1 or loss of association between MLP1 and the anionic phospholipid phosphate PIP2 would significantly alter membrane association and EnNaC activity in mAoEC.

Functional and metabolomic analysis of urinary extracellular vesicles from juvenile mice with renal compensatory hypertrophy.

Unilateral nephrectomy, a procedure reducing kidney mass, triggers a compensatory response in the remaining kidney, increasing its size and function to maintain a normal glomerular filtration rate (GFR). Recent research has highlighted the role of extracellular vesicles (EVs) in renal physiology and disease, although their involvement in unilateral nephrectomy has been underexplored. In this study, unilateral nephrectomy was performed on young mice, and urinary extracellular vesicles (uEVs) characterization and cargo were analyzed.

Dysregulation of kidney proteases in the pathogenesis of hypertension following unilateral nephrectomy in juvenile mice.

Background: Unliteral nephrectomy (UNX) results in the reduction of kidney mass. The remaining kidney undergoes compensatory renal growth via hypertrophy of the glomeruli and renal tubules to maintain a normal glomerular filtration rate (GFR). These compensatory mechanisms result in increased capillary pressure and glomerular hyperfiltration to increase single nephron GFR.

Tempol treatment normalizes membrane expression of epithelial transport proteins in the kidney of salt-loaded hypertensive diabetic db/db mice.

Objective: Hypertension exacerbates the progression and severity of diabetic kidney disease. In this study, we addressed the hypothesis that tempol acts at multiple segments of the nephron to normalize the abundance of sodium coupled epithelial transport proteins in the luminal plasma membrane to mitigate high blood pressure in salt-loaded hypertensive diabetic db/db mice.

Methods: Soluble and membrane fractions from freshly homogenized kidney cortex tissue samples were resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and probed for specific proteins by Western blotting.

Male kidney-specific BMAL1 knockout mice are protected from K-deficient, high-salt diet-induced blood pressure increases.

The circadian clock protein basic helix-loop-helix aryl hydrocarbon receptor nuclear translocator-like protein 1 (BMAL1) is a transcription factor that impacts kidney function, including blood pressure (BP) control. Previously, we have shown that male, but not female, kidney-specific cadherin Cre-positive BMAL1 knockout (KS-BMAL1 KO) mice exhibit lower BP compared with littermate controls. The goal of this study was to determine the BP phenotype and immune response in male KS-BMAL1 KO mice in response to a low-K high-salt (LKHS) diet.

Extracellular Vesicles: Investigating the Pathophysiology of Diabetes-Associated Hypertension and Diabetic Nephropathy.

Extracellular vesicles (EVs) include exosomes, microvesicles, and apoptotic bodies. EVs are released by all cell types and are found in biological fluids including plasma and urine. Urinary extracellular vesicles (uEVs) are a mixed population of EVs that comprise small EVs that are filtered and excreted, EVs secreted by tubular epithelial cells, and EVs released from the bladder, urethra, and prostate.

Decreased MARCKS Protein Expression in Kidney Cortex Membrane Fractions of Cathepsin B Knockout Mice Is Associated with Reduced Lysophosphatidylcholine and Protein Kinase C Activity.

Cathpesin B is a multi-functional protease that plays numerous roles in physiology and pathophysiology. We hypothesized that actin cytoskeleton proteins that are substrates of cathepsin B, various lipids, and kinases that are regulated by lipids would be down-regulated in the kidney of cathepsin B knockout mice. Here, we show by Western blot and densitometric analysis that the expression and proteolysis of the actin cytoskeleton proteins myristoylated alanine-rich C-kinase substrate (MARCKS) and spectrin are significantly reduced in kidney cortex membrane fractions of cathepsin B knockout mice compared to C57B6 wild-type control mice.

Metformin Alleviates Diabetes-Associated Hypertension by Attenuating the Renal Epithelial Sodium Channel.

Diabetic nephropathy is the primary cause of morbidity in type 2 diabetes mellitus (T2DM) patients. New data indicate that hypertension, a common comorbidity in T2DM, can worsen outcomes of diabetic nephropathy. While metformin is a commonly prescribed drug for treating type 2 diabetes, its blood pressure regulating ability is not well documented.

Metabolic Characterization and Glyceraldehyde-3-Phosphate Dehydrogenase-Dependent Regulation of Epithelial Sodium Channels in hPheo1 Wild-type and SDHB Knockdown Cells.

Pheochromocytomas (PCC) and paragangliomas (PGL) are rare neuroendocrine tumors with limited curative treatment options outside of surgical resection. Patients with mutations in succinate dehydrogenase subunit B (SDHB) are at an increased risk of malignant and aggressive disease. As cation channels are associated with tumorigenesis, we studied the expression and activity of cation channels from the Degenerin superfamily in a progenitor cell line derived from a human PCC.

COVID-19 Plasma Extracellular Vesicles Increase the Density of Lipid Rafts in Human Small Airway Epithelial Cells.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus is the causative agent of the COVID-19 disease. COVID-19 viral infection can affect many cell types, including epithelial cells of the lungs and airways. Extracellular vesicles (EVs) are released by virtually all cell types, and their packaged cargo allows for intercellular communication, cell differentiation, and signal transduction.