A Newly Identified Protective Role of C5a Receptor 1 in Kidney Tubules against Toxin-Induced Acute Kidney Injury.

Acute kidney injury (AKI) remains a major reason for hospitalization with limited therapeutic options. Although complement activation is implicated in AKI, the role of C5a receptor 1 (C5aR1) in kidney tubular cells is unclear. Herein, aristolochic acid nephropathy (AAN) and folic acid nephropathy (FAN) models were used to establish the role of C5aR1 in kidney tubules during AKI in germline C5ar1, myeloid cell-specific, and kidney tubule-specific C5ar1 knockout mice.

USP20 deletion promotes eccentric cardiac remodeling in response to pressure overload and increases mortality.

Left ventricular hypertrophy (LVH) caused by chronic pressure overload with subsequent pathological remodeling is a major cardiovascular risk factor for heart failure and mortality. The role of deubiquitinases in LVH has not been well characterized. To define whether the deubiquitinase ubiquitin-specific peptidase 20 (USP20) regulates LVH, we subjected USP20 knockout (KO) and cognate wild-type (WT) mice to chronic pressure overload by transverse aortic constriction (TAC) and measured changes in cardiac function by serial echocardiography followed by histological and biochemical evaluations.

Investigation of cardiorenal outcomes and incidence of genitourinary tract infection after combined SGLT2 inhibitor and ACEI/ARB use in patients with chronic kidney disease stages 3-5: A real-world retrospective cohort study in Taiwan.

Sodium‒glucose cotransporter-2 (SGLT2) inhibitors offer glycaemic and cardiorenal benefits in the early stage of chronic kidney disease (CKD). However, the use of SGLT2 inhibitors may increase the risk of genitourinary tract infection (GUTI). Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) may also cause deterioration of kidney function.

Thiazide diuretics versus loop diuretics in stage 3-5 CKD: impact on cardiorenal outcomes.

Objectives: The association between diuretic use and cardiorenal outcomes remains limited in patients with stage 3-5 chronic kidney disease (CKD) and hypertension. To address this gap, we aim to investigate the long-term clinical impact of diuretic use with its pharmacological classification in Taiwanese patients with stage 3-5 CKD and hypertension who were concurrently received angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs).

Methods: Using data from the National Health Insurance Research Database (January 2008 to December 2019), we focused on individuals with stage 3-5 CKD receiving ACEIs/ARBs between 2010 and 2018.

Membranoproliferative Glomerulonephritis Pattern of Injury.

Membranoproliferative glomerulonephritis (MPGN) is no longer a disease but a pattern of injury in various diseases. Characterized by electron-dense deposits, mesangial proliferation, and duplication of the glomerular basement membrane, MPGN was previously classified by findings seen by electron microscopy. However, recognizing complement dysfunction in relation to cases with the MPGN pattern of injury substantially changed our view of its pathogenesis.

Impact of chronic kidney disease and end-stage renal disease on the mid-term adverse outcomes in diabetic patients with cardiovascular diseases.

The evidence for the impact of renal dysfunction in patients with diabetes mellitus (DM) and first cardiovascular diseases on mid-term adverse outcomes remain scarce. This study included the data of patients with DM having first atherosclerotic cardiovascular disease (ASCVD) or congestive heart failure (CHF) from the Taipei Medical University Clinical Research Database. A Cox proportional hazards regression model was used to assess the impact of chronic kidney disease (CKD) or end-stage renal disease (ESRD) on the 1-year mortality and recurrent ASCVD/CHF outcomes.

Viral Glomerulopathy.

Background: The association between viral infections and glomerular diseases, commonly known as "viral glomerulopathies," has been described in various clinical scenarios for decades. Despite advancements in diagnostic tools, it remains challenging to establish a causative link fully.

Summary: Data from mouse models have substantiated clinical observations and implicate direct viral infection in the pathogenesis of viral glomerulopathy, particularly in human immunodeficiency virus-associated nephropathy.

Cutting Edge: Neutrophil Complement Receptor Signaling Is Required for BAFF-Dependent Humoral Responses in Mice.

T cell-independent (TI) B cell responses to nonprotein Ags involve multiple cues from the innate immune system. Neutrophils express complement receptors and activated neutrophils can release BAFF, but mechanisms effectively linking neutrophil activation to TI B cell responses are incompletely understood. Using germline and conditional knockout mice, we found that TI humoral responses involve alternative pathway complement activation and neutrophil-expressed C3a and C5a receptors (C3aR1/C5aR1) that promote BAFF-dependent B1 cell expansion and TI Ab production.

The single-cell landscape of kidney immune cells reveals transcriptional heterogeneity in early diabetic kidney disease.

The pathogenesis of diabetic kidney disease (DKD) involves multifactorial processes that converge to initiate and advance the disease. Although DKD is not typically classified as an inflammatory glomerular disease, mounting evidence supports the involvement of kidney inflammation as a key contributor in DKD pathogenesis, particularly through macrophages. However, detailed identification and corresponding phenotypic changes of macrophages in DKD remain poorly understood.

Aged glomeruli: a link between PD-1 and podocytes.

Understanding the loss of kidney function resulting from kidney aging has become an emerging research focus that will facilitate the future development of antisenolytic treatments. In this issue of the JCI, Pippin et al. first identified PD-1 upregulation in the aged mouse podocyte via unbiased RNA-seq analysis.

Happy gut, happy kidneys? Restoration of gut microbiome ameliorates acute and chronic kidney disease.

In a new study, Zhu et al. (2021) show that mitigating dysbiosis by the probiotic L. casei Zhang reduces kidney inflammation via restoring short-chain fatty acid-producing gut microbiome and nicotinamide metabolism.

IgA Nephropathy After SARS-CoV-2 Vaccination.

Here we present the first case of newly diagnosed IgA nephropathy (IgAN) after a SARS-CoV-2 vaccination. A 30-year-old man with no known past medical history presented with gross hematuria and subnephrotic proteinuria 24 hours after the second dose of the mRNA-1273 SARS-CoV-2 vaccine. A kidney biopsy showed IgAN.

The deubiquitinase ubiquitin-specific protease 20 is a positive modulator of myocardial β-adrenergic receptor expression and signaling.

Reversible ubiquitination of G protein-coupled receptors regulates their trafficking and signaling; whether deubiquitinases regulate myocardial β-adrenergic receptors (βARs) is unknown. We report that ubiquitin-specific protease 20 (USP20) deubiquitinates and attenuates lysosomal trafficking of the βAR. βAR-induced phosphorylation of USP20 Ser-333 by protein kinase A-α (PKAα) was required for optimal USP20-mediated regulation of βAR lysosomal trafficking.

Proteinuric Kidney Diseases: A Podocyte's Slit Diaphragm and Cytoskeleton Approach.

Proteinuric kidney diseases are a group of disorders with diverse pathological mechanisms associated with significant losses of protein in the urine. The glomerular filtration barrier (GFB), comprised of the three important layers, the fenestrated glomerular endothelium, the glomerular basement membrane (GBM), and the podocyte, dictates that disruption of any one of these structures should lead to proteinuric disease. Podocytes, in particular, have long been considered as the final gatekeeper of the GFB.

Acute Kidney Injury and Progression of Diabetic Kidney Disease.

Diabetic kidney disease, commonly termed diabetic nephropathy (DN), is the most common cause of end-stage kidney disease (ESKD) worldwide. The characteristic histopathology of DN includes glomerular basement membrane thickening, mesangial expansion, nodular glomerular sclerosis, and tubulointerstitial fibrosis. Diabetes is associated with a number of metabolic derangements, such as reactive oxygen species overproduction, hypoxic state, mitochondrial dysfunction, and inflammation.

Autosomal Dominant Tubulointerstitial Kidney Disease Due to MUC1 Mutation.

Mucin 1 kidney disease, previously referred to as medullary cystic kidney disease type 1, is a rare hereditary kidney disease. It is one of several diseases now termed autosomal dominant tubulointerstitial kidney disease, as proposed by a KDIGO (Kidney Disease: Improving Global Outcomes) consensus report in 2014. Autosomal dominant tubulointerstitial kidney diseases share common clinical findings, such as autosomal dominant inheritance, bland urinary sediment, absent to mild proteinuria, and progressive loss of kidney function.

Mdm2 regulates cardiac contractility by inhibiting GRK2-mediated desensitization of β-adrenergic receptor signaling.

The oncoprotein Mdm2 is a RING domain-containing E3 ubiquitin ligase that ubiquitinates G protein-coupled receptor kinase 2 (GRK2) and β-arrestin2, thereby regulating β-adrenergic receptor (βAR) signaling and endocytosis. Previous studies showed that cardiac Mdm2 expression is critical for controlling p53-dependent apoptosis during early embryonic development, but the role of Mdm2 in the developed adult heart is unknown. We aimed to identify if Mdm2 affects βAR signaling and cardiac function in adult mice.

Circulating Exosomes Induced by Cardiac Pressure Overload Contain Functional Angiotensin II Type 1 Receptors.

Background: Whether biomechanical force on the heart can induce exosome secretion to modulate cardiovascular function is not known. We investigated the secretion and activity of exosomes containing a key receptor in cardiovascular function, the angiotensin II type I receptor (AT1R).

Methods And Results: Exosomes containing AT1Rs were isolated from the media overlying AT1R-overexpressing cells exposed to osmotic stretch and from sera of mice undergoing cardiac pressure overload.