American Journal of Physiology-Renal Physiology

Bladder outlet obstruction leads to pathological remodeling and emergence of lower urinary tract symptoms. Although relief of obstruction is associated with symptomatic improvement, it is not universally successful, reflecting persistent alterations in the bladder. Reliable surrogate biomarkers of obstruction are lacking, particularly early in the disease course before irreversible damage to the bladder may have occurred. In this study, re-analysis of publicly available transcriptomic datasets from diverse rodent models of obstruction identified tissue transcripts including Cthrc1, Grem1, Ltbp2 and Msn that were induced in response to injury. Candidate markers were validated experimentally in an independent model of neurogenic obstruction demonstrating time-dependent changes. Candidate markers were also attenuated with either surgical removal of obstruction or treatment with anticholinergic medication or inosine. Integrated analysis of tissue transcriptomics data and tissue and urine proteomics data from a model of neurogenic obstruction revealed significant concordance between markers observed in tissue and urine. Urinary proteomics analysis identified a statistically significant increase in MSN in patients with neurogenic bladder compared to unaffected controls. These findings identify tissue and urine biomarkers of both non-neurogenic and neurogenic obstruction that may reflect early changes in obstructive uropathy that could be monitored in a non-invasive manner.

NKCC2, localized to the apical membrane of thick ascending limb epithelial cells, is essential for renal salt handling and systemic electrolyte homeostasis. NKCC2 undergoes extensive ubiquitylation, with the E3 protein ligase Nedd4-2 implicated as a key regulator. However, progress has been limited by challenges expressing NKCC2 in mammalian cell lines, hindering mechanistic studies of NKCC2 ubiquitylation. Therefore, the aims of this study were to develop a mammalian cell model enabling mechanistic investigations of NKCC2 ubiquitylation, including the role of Nedd4-2 and the functional consequences of site-specific modification. A tetracycline-inducible MDCKI cell line was generated expressing human NKCC2 and used to assess Nedd4-2-dependent and site-specific ubiquitylation of NKCC2 using biochemical, imaging, and functional assays. The MDCKI cell line demonstrated stable, inducible expression of full-length human NKCC2. In this cell line, mutating the ubiquitylation site at K871 increased membrane abundance and uptake activity, without altering internalization rates. Nedd4-2 co-immunoprecipitated with NKCC2, and Nedd4-2 deletion increased total, but not membrane NKCC2 abundance. In summary, ubiquitylation on NKCC2 at K871 plays a key role in controlling NKCC2 membrane localization and thus function. Although Nedd4-2 can modulate NKCC2 abundance, it is not involved in NKCC2 trafficking. We conclude that the generated cell line provides a robust model for mechanistic studies of NKCC2 and will aid studies examining posttranslational regulation of NKCC2.

IntroductionImmune checkpoint inhibitors (ICIs) enhance antitumor responses by blocking inhibitory receptors, including PD-1 and CTLA-4. Overactivation can trigger systemic toxicity akin to autoimmune diseases, including kidney manifestations. We sought to 1) profile immune signaling and 2) interrogate potential mechanisms of ICI-related kidney injury in a Human Immune System (HIS) tumor-bearing mouse model treated with nivolumab and ipilimumab. MethodsImmunodeficient BRGS (BALB/c-Rag2nullIl2r{gamma}nullSirpNOD) neonates were engrafted with human CD34+ cells to generate HIS-BRGS mice. Human MDA-MB-231 tumor cells were implanted subcutaneously; once tumors reached [~]150 mm3, mice received weekly intraperitoneal vehicle (PBS) or ICI (nivolumab 20 mg/kg + ipilimumab 10 mg/kg) for 4 weeks (Veh BRGS n=4; ICI BRGS n=6; Veh HIS-BRGS n=7; ICI HIS-BRGS n=7). Kidneys were evaluated by histopathology (H&E, TEM), flow cytometry for human immune phenotypes, multiplex ELISA (80 human proteins; 10 injury biomarkers), bulk RNA sequencing, and targeted qPCR. Pearson correlations identified predictors of histopathological injury. ResultsRenal vasculitis and interstitial nephritis were observed only in ICI-treated HIS-BRGS mice. These kidneys showed a shift toward CD4+ T-cell enrichment with an increased TNF- production capacity compared to CD8+ counterparts. Toxicity was accompanied by increased renal concentrations of human cytokines, chemokines, and soluble receptors. ICI treatment significantly elevated serine proteases (Granzyme A/B) and NGF-{beta}, while decreasing IL-4. Interstitial nephritis correlated with renal PD-1 and MIF. Renal vasculitis correlated with kidney PD-1, CCL1, MIF, Granzyme A, IL-15, and BAFF. Traditional injury biomarkers (KIM-1, NGAL) remained unchanged; however, a trending decrease in EGF was observed. ConclusionsOur study suggests that shifts in human T-cell populations and specific immune proteins could serve as promising biomarkers and mechanistic targets for ICI nephrotoxicity. The tumor-bearing HIS-BRGS mouse model reproducibly recapitulates the histopathological and immunological features of human ICI-induced nephrotoxicity and represents a validated preclinical platform for testing novel therapeutic interventions to preserve kidney function during cancer immunotherapy. Translational StatementImmune checkpoint inhibitor (ICI)-associated nephrotoxicity occurs in up to 25% of treated patients, yet the immunological mechanisms driving renal injury remain poorly characterized due to the scarcity of human biopsy material and the absence of robust preclinical models that recapitulate human immune responses. This study demonstrates that tumor-bearing humanized immune system (HIS) mice treated with combined nivolumab and ipilimumab reproducibly develop renal vasculitis and interstitial nephritis mediated by a human CD4+ T cell-dominant infiltrate, mirroring the clinicopathological features reported in patients with ICI-associated acute kidney injury. By integrating histopathology, flow cytometry, multiplex proteomics, and transcriptomics, we identify a coordinated immune network, including IL-15, CCL1, MIF, GZMA, and BAFF, that correlates with the severity of renal pathology and represents tractable mechanistic targets and candidate biomarkers. These findings provide a validated preclinical platform for dissecting irAE mechanisms and testing novel therapeutic strategies to preserve kidney function during cancer immunotherapy.

BackgroundPolycystic kidney disease (PKD) is the leading genetic cause of renal failure, resulting in the accumulation of fluid filled cysts and gross enlargement of the kidney. Mutations in PKD1 or PKD2, which encode ciliary polycystin proteins, are the most common cause of PKD. These proteins function in a cilia-dependent cyst activation (CDCA) pathway-one that requires cilia for its pro-cystic function-yet the molecular driver(s) of this pathway are unknown. ARL13B is a regulatory GTPase enriched in cilia and links to renal cystogenesis. ARL13B possesses guanine nucleotide exchange factor (GEF) activity for ARL3, another ARL with links to cilia. MethodsWe used two distinct Arl13b mouse alleles to investigate whether ARL13B is a component of the CDCA pathway: Arl13bV358Aencodes for enzymatically normal ARL13B that is undetectable in cilia, and Arl13bR79Qencodes for cilia-localized ARL13B lacking a residue critical for its ARL3 GEF activity. We used these alleles in a Pkd1-deficient adult mouse model and investigated renal morphology (H&E and cystic index analysis), physiology (blood urea nitrogen measurements), renal fibrosis (picrosirius staining and -smooth muscle actin levels), renal injury (SOX9 immunofluorescent staining and quantification), and Wnt signaling ({beta}-catenin and cyclin D1 protein levels). ResultsWe found that loss of ciliary ARL13B or mutation of a single residue critical for its ARL3 GEF activity suppressed Pkd1-dependent cysts. We observed reductions in kidney size, cystic index, and blood urea nitrogen. We also observed suppression of renal fibrosis, renal injury, and {beta}-catenin and cyclin D1 protein levels. ConclusionsOur results identified a subcellular location and mechanism driving Pkd1-dependent renal cystogenesis. We demonstrated that expression of a critical residue for ARL13Bs GEF activity specifically in cilia is a key mechanism of the CDCA pathway driving renal cystogenesis. Key PointsO_LILoss of ciliary ARL13B suppressed renal cystogenesis in an adult mouse model of polycystic kidney disease (PKD) without ablating cilia C_LIO_LILoss of ciliary ARL13B or mutation of the residue critical for its GEF activity did not affect renal morphology or physiology in a PKD mouse model C_LIO_LIMutation of a residue critical for ARL13B activation of ARL3 suppressed cystic phenotypes in Pkd1-dependent cysts C_LI

Ciliogenesis associated kinase 1 (CILK1) deficiency in human and mice results in kidney developmental defects including cystogenesis. However, the biology of CILK1 in autosomal dominant polycystic kidney disease (ADPKD), the most common inherited kidney disease, remains to be investigated. Here, we show that CILK1 is overexpressed in dedifferentiated cells of renal tissue from ADPKD human patients in comparison to normal control tissue samples. We demonstrate that CILK1 overexpression results in protein accumulation in a non-phosphorylated inactive form. Using mouse polycystic kidney disease models, we reveal that inactive CILK1 accumulation is progressive over the course of disease progression. We show that genetic inactivation of the Polycystic Kidney Disease 1 (PKD1) gene is sufficient to trigger CILK1 accumulation. Altogether, these findings demonstrate that CILK1 regulation is altered in ADPKD and it represents a hallmark of disease progression.

Sphingosine-1-phosphate lyase insufficiency syndrome (SPLIS) is a rare condition causing nephrotic syndrome, neuropathy, and other manifestations. SPLIS is caused by mutations in SGPL1, which encodes sphingosine-1-phosphate lyase (SPL), a pyridoxal 5-phosphate (PLP)-dependent enzyme needed to degrade the bioactive sphingolipid sphingosine-1-phosphate (S1P). Supplementation with the PLP precursor pyridoxine benefits some individuals with PLP-dependent enzymopathies. We sought to establish whether pyridoxine has therapeutic activity in SPLIS. Neurological improvement, plasma S1P normalization, and increased SPL activity in patient-derived fibroblasts were observed after pyridoxine supplementation in a patient with R222Q-variant SPLIS. Additionally, PLP dose-dependently augmented recombinant R222Q-variant SPL activity. To further explore pyridoxines effects, gene editing was employed to create an R222Q-variant SPLIS mouse model. SPLR222Q mice fed pyridoxine-enriched chow lacked obvious phenotypes. However, SPL inactivation, S1P accumulation, wasting, anemia, proteinuria, and glomerulosclerosis developed in SPLR222Q but not WT mice fed chow with reduced pyridoxine. Ultrastructural analysis and super-resolution microscopy showed podocyte loss and foot process effacement. Transcriptional profiling revealed a pattern of cytokine upregulation and extracellular matrix remodeling. Inhibiting S1P production prevented nephrosis in SPLR222Q mice fed chow lacking pyridoxine. Our findings establish a novel SPLIS mouse model that recapitulates R222Q-variant SPLIS, demonstrates its responsiveness to pyridoxine, and implicates S1P in its pathophysiology.

ObjectiveRecurrent urinary tract infections (rUTIs) significantly decrease quality of life and antibiotics are becoming increasingly less effective due to antimicrobial resistance. Alternative effective treatment strategies are urgently needed for rUTIs. Prior studies have indicated that women can experience resolved or improved rUTI following electrofulguration (EF). To further investigate these findings, we report on the design and methodology behind a randomized trial examining two treatment arms: standard prolonged antibiotic treatment with nitrofurantoin (NF) alone or in combination with EF. Patients and MethodsThe aim of this randomized trial is to determine, at two institutions, the efficacy of two interventions for rUTI associated with early stages of chronic cystitis (stages 1 and 2): conventional 6 months low-dose (100mg) NF daily antibiotic suppression alone (NF) or conventional NF with EF (EF + NF). The study is also designed to analyze changes in the urinary microbiomes in the two different treatment arms and to determine the durability of clinical outcomes in both treatment arms at 2 years after the end of each intervention. The primary outcomes will be obtained from 6 to 18 months, as well as 18 - 30 months following completion of the original 6-month intervention. Failure is defined based on UTI symptoms documented by a validated questionnaire with a documented urine culture confirming a bacterial strain at each UTI episode following the end of the 6-month intervention. ConclusionsThis randomized trial is designed to examine the efficacy and durability of treating women with rUTIs using the standard of care of NF alone, or an EF procedure with NF.

Regulation of water permeability in the collecting duct is important for osmoregulatory acclimation in teleost fish. In hyperosmotic environments such as seawater (SW), the teleost kidney functions as a site of divalent ion excretion. The collecting ducts reabsorb Na+, Cl-, and water, thereby reducing urine volume and producing small amounts of isotonic urine with high concentrations of divalent ions. In hypoosmotic environments such as freshwater (FW) or low-salinity brackish water (BW), the kidney produces large volumes of hypotonic urine and serves as a site of water excretion; under these conditions, the collecting ducts reabsorb Na+ and Cl- but not water. To identify aquaporins (Aqps) involved in regulating water permeability in the collecting ducts of teleosts, we analyzed renal Aqp expression in a euryhaline marine fish, the Japanese pufferfish (Takifugu rubripes), which possesses 16 Aqp genes in its genome, seven of which (Aqp1aa, 1ab, 3a, 4a, 7, 8bb, and 11a) are expressed in the kidney. Quantitative RT-PCR analysis showed that Aqp1aa and Aqp4a were highly expressed in collecting duct tissues, and that Aqp1aa expression was markedly reduced in fish acclimated to BW. Immunohistochemistry revealed apical localization of Aqp1aa and basolateral localization of Aqp4 in collecting duct cells, with apical Aqp1aa downregulated in BW. These results suggest that Aqp1aa and Aqp4 mediate water reabsorption in SW and that downregulation of Aqp1aa contributes to hypotonic urine production in BW. NEW & NOTEWORTHYRegulation of water permeability in the collecting duct is important for osmoregulation in teleost fish. Expression analyses of aquaporins (Aqps) in the marine pufferfish Takifugu rubripes showed that Aqp1aa and Aqp4a are highly expressed in the collecting duct and localized to the apical and basolateral membranes, respectively. Renal Aqp1aa expression was markedly reduced in fish acclimated to hypoosmotic brackish water. These results indicate that collecting duct water permeability is regulated by Aqp1aa expression.

BackgroundAPRIL and BAFF are TNF superfamily cytokines that regulate B-cell development, survival, and antibody production, and are emerging therapeutic targets for IgA nephropathy (IgAN). Selective APRIL and dual APRIL/BAFF inhibitors both reduce IgA and proteinuria in IgAN clinical trials, but whether their broader immunological consequences differ has not been systematically characterized. MethodsWe compared selective APRIL and dual APRIL/BAFF inhibition using influenza vaccination and lethal challenge, KLH immunization, serological profiling, and flow cytometry in mice, alongside human B-cell survival assays in vitro. Single-cell CITE-seq and in situ spatial transcriptomics were applied to characterize molecular and tissue-level changes in the spleen. ResultsBoth modes of inhibition reduced serum IgA by [&ge;]60% in mice. However, dual APRIL/BAFF inhibition nearly abolished vaccine-mediated protection against lethal influenza challenge (10% versus 70% survival in controls; p < 0.01), whereas selective APRIL inhibition had limited impact on protective immunity. This functional divergence was underpinned by broad cellular disruption under dual blockade, including >80% depletion of splenic B cells, loss of T follicular helper cells, and impaired antigen-specific IgM and IgG responses. Selective APRIL inhibition left these populations and responses largely intact. Consistent with these findings, human B-cell survival in vitro was dependent on BAFF, not APRIL. Single-cell and spatial transcriptomics revealed that dual blockade collapsed follicular architecture, eliminated germinal centers, and disrupted chemokine organization, whereas these structures remained intact under selective APRIL inhibition. At the molecular level, dual blockade, but not selective APRIL inhibition, downregulated NF-{kappa}B survival signaling and antigen presentation programs and shifted surviving germinal center B cells toward a pro-apoptotic state. ConclusionsSelective APRIL and dual APRIL/BAFF inhibition both reduce IgA, the pathologically relevant isotype in IgAN, but only dual blockade disrupts B-cell maturation, germinal center function, tissue architecture, and protective immunity. These findings inform the benefit-risk assessment of chronic B cell-targeting therapies in IgAN.

Obesity is associated with chronic low-grade systemic inflammation of adipose tissue and is often linked to intestinal epithelial barrier (IEB) dysfunction. The present study aimed to evaluate the effects of in vitro gastrointestinal digests of bovine milk containing A1B or A2 {beta}-casein variants on leaky IEB and adipocyte inflammation. Digests of A1B (DA1B) and A2 (DA2) milk were administered to an in vitro Caco-2/HT-29 intestinal cell co-culture mimicking a leaky gut. Intestinal absorbed fractions derived from A1B (MA1B) and A2 (MA2) were administered to hMADS adipocytes. DA1B and DA2 did not modify intestinal permeability, either in the absence or the presence of inflammation. DA1B reduced Claudin-1 mRNA, as well as zonula occludens-1 mRNA and protein expression. Both DA1B and DA2 increased interleukin-8 expression, but only DA1B increased tumor necrosis factor-. In human adipocytes, MA1B, and to a lesser extent MA2, increased the expression of pro-inflammatory markers monocyte chemoattractant protein-1 and interleukin-6, while reducing adiponectin levels. DA2 preserved in vitro leaky IEB integrity and exhibited a lower inflammatory potential in both leaky gut and adipocytes compared to DA1B. This study is the first to establish a link among A2 milk, leaky gut syndrome, and obesity.

ObjectiveTo 1) determine the expression and distribution of all PDE4 isozymes (A-D) along the length of the anterior urethra, 2) culture fibroblasts and epithelial cells from healthy and strictured urethras, 3) investigate an in vitro model of anterior urethral stricture disease (aUSD), and 4) assess the therapeutic potential of phosphodiesterase-4 (PDE4) inhibitors and testosterone compared to paclitaxel. MethodsThe presence and relative abundance of PDE4 isozymes (A-D) was confirmed using immunohistochemistry on 5 male cadaveric urethras. Human urethral fibroblasts (FBs) were cultured from healthy control urethras of patients undergoing vaginoplasty (n=3) and from idiopathic bulbar urethral strictures (L2S1E2) of patients undergoing urethroplasty (n=3). Epithelial cells (ECs) were cultured from a healthy control urethra and two urethral strictures. To investigate a model of aUSD, Control FBs were stimulated with TGF{beta}1 and compared to Stricture FBs on assays of cell proliferation and expression of genes relevant to aUSD pathophysiology. To test therapeutics, Stricture FBs were treated with the PDE4 inhibitor, roflumilast, testosterone (T), or paclitaxel and compared to Control FBs on the previously mentioned assays and cell viability. ResultsPDE4- A, B, and D were detected along the length of the urethra. Expression levels did not differ between urethral regions. TGF{beta}1 altered proliferation and gene expression in a dose-dependent manner. Roflumilast and T preserved cell viability and proliferation and decreased expression of genes positively associated with auSD. ConclusionUrethral FBs and ECs can be cultured from healthy and strictured surgical specimens, enabling in vitro research. PDE4 inhibitors and T may be non-cytotoxic alternatives or additions to paclitaxel for aUSD. HighlightsO_LIPDE4 isozymes A, B, and D are expressed in adult anterior urethras C_LIO_LIPDE4 is expressed equally from proximal bulbar to meatal urethra C_LIO_LIEpithelial cells and fibroblasts can be cultured from healthy and stricture urethra C_LIO_LITGF{beta}1 may not be an optimal method to model aUSD in vitro C_LIO_LIUnlike paclitaxel, roflumilast and testosterone are not toxic to urethral cells C_LI

Chromophobe renal cell carcinoma (ChRCC) accounts for 5% of all renal cancer cases. Despite its generally indolent behavior and low mutational burden, there is no targeted therapy for metastatic ChRCC. Profilin-1 (Pfn1), a cytoskeletal regulator of actin and tubulin dynamics, has emerged as a potential oncogenic driver in several cancers including RCC, but its role in ChRCC, remains undefined. We observed elevated Pfn1 expression in stage IV ChRCC patients, implicating Pfn1 in advanced disease progression. To investigate this, we manipulated Pfn1 expressions in two ChRCC cell lines UOK276 and RCJ41M. Pfn1 knockdown (KD) significantly reduced proliferation, invasion, and colony formation, whereas Pfn1 overexpression (OE) in UOK276 enhanced ChRCC aggressive phenotypes. Pharmacological inhibition of Pfn1 significantly suppressed proliferation and clonogenic growth in both cell lines. Additionally, Pfn1 KD increased intracellular ROS accumulation, while overexpressed reduced ROS levels, linking cytoskeletal regulation to oxidative stress control. Together, these findings position Pfn1 as a critical mediator of ChRCC progression, linking cytoskeletal remodeling to aggressive tumor behavior. This work highlights Pfn1 as a potential therapeutic target and establishes a framework for cytoskeletal-focused strategies in advanced ChRCC.

BackgroundThe gut-kidney axis plays a direct role in gastrointestinal and kidney health. Gut-derived metabolites like uremic toxins are associated with the pathophysiology of feline chronic kidney disease (CKD). The aim of the study was to identify novel fecal biomarkers and investigate the roles of gastrointestinal metabolites in feline CKD. ResultsFecal samples from 41 healthy non-CKD (control) and 67 CKD cats, including 5 IRIS stage 1 (CKD1), 37 stage 2a (CKD2a), 18 stage 2b (CKD2b), and 7 stage 3 (CKD3), were subject to fecal untargeted metabolomics and targeted short-chain fatty acid (SCFA) analyses. Multiple linear regression, adjusted for sex, age, body weight and study site, identified 64 differential metabolites between control and across CKD groups (P<0.0001 and FDR<0.10). Approximately 65% of the metabolites were lipids, including polyunsaturated long-chain fatty acids, acylcarnitines, and ceramides. Random Forest algorithm selected N1-methyl-2-pyridone-5-carboxamide (2PY), a uremic toxin from nicotinamide catabolism, as the top fecal marker for classifying feline CKD. Fecal 2PY was increased in CKD1 (P = 0.03), CKD2a, CKD2b, and CKD3 (all P<0.0001) compared to the controls. Data mining revealed serum concentration of 2PY was significantly increased with severity of CKD in cats, possibly due to impaired renal excretion. Cholesterol and arachidonic acid, markers for enterocyte shedding and inflammation, were increased in CKD3 versus control (both P<0.05). In healthy non-CKD cats, evident suggested fecal lipids increased with age (P<0.0001), and were higher in females versus males (P<0.0001). While fecal indole and p-cresol were increased in CKD3 versus control (both P<0.05), no change was observed in indoxyl sulfate (IS) or p-cresol sulfate (PCS). Fecal indole-3-acetic acid (IAA) was decreased in several CKD groups compared to the controls (all P<0.05). Finally, two branched SCFAs, isobutyrate and isovalerate, were increased in CKD3 versus control (both P<0.05). ConclusionsThe study revealed 2PY as a novel marker and unveiled profound alterations in intestinal lipid compositions with a potential link to gut barrier integrity and inflammation in CKD.

IgA nephropathy (IgAN) is a common primary glomerulonephritis characterized by glomerular immune-complex deposits with (co)dominant IgA. These deposits are enriched for IgA1 glycoforms with some O-glycans deficient in galactose (Gd-IgA1). Circulating Gd-IgA1 is bound by IgG autoantibodies to form immune complexes, some of which deposit in glomeruli. Genomic and immunologic studies indicate involvement of pro-inflammatory signaling pathways in the production of Gd-IgA1 in IgAN. Genomic studies identified multiple genetic loci associated with IgAN and suggested a convergence on the NF-{kappa}B pathway, including RELA, the gene encoding the NF-{kappa}B subunit p65. However, the mechanisms by which NF-{kappa}B pathways may affect O-glycosylation in IgA1-producing cells are unknown. Using EBV-immortalized B cells derived from peripheral-blood mononuclear cells of IgAN patients and healthy controls that have constitutively activated NF-{kappa}B, we report that inhibition of NF-{kappa}B/p65 by a selective IKK{beta} inhibitor TPCA-1 reduced phosphorylation of NF-{kappa}B/p65 at S536 and decreased production of IgA1 and, conversely, increased Gd-IgA1 production. This was likely related to reduced expression of C1GALT1 gene that encodes the enzyme responsible for galactosylation of IgA1 O-glycans. Flow-cytometry imaging revealed changes in nuclear translocation and co-localization of the NF-{kappa}B/p65 with co-transcriptional factor SP1, a transcriptional activator of C1GALT1, suggesting that NF-{kappa}B pathway affects IgA1 O-glycosylation via SP1 transcriptional control of C1GALT1 expression. Furthermore, prolonged IKK{beta} inhibition altered B cell subpopulations, enhancing generation of cells with a plasmablast-like phenotype, characterized by high SSC MFI and CD138 expression. Together, these findings provide functional evidence for involvement of NF-{kappa}B/p65 and its transcriptional partners in IgA1 O-glycosylation. HighlightsO_LIIKK{beta} inhibition reduced C1GALT1 expression and thereby increased galactose-deficient IgA1 (Gd-IgA1) production in immortalized human B cells. C_LIO_LISP1+ subpopulations, a transcriptional activator of C1GALT1, declined after sustained NF-{kappa}B inhibition. C_LIO_LINF-{kappa}B inhibition shifted a subpopulation of B cells into a plasmablast-like phenotype. C_LIO_LIThis study links NF-{kappa}B signaling with the GWAS-identified RELA susceptibility locus and IgA1 O-glycosylation. C_LI

BackgroundHypertension is a highly heritable cardiovascular disorder and a major determinant of cardiometabolic disease, including diabetes. However, the regulatory genes and tissue-specific mechanisms underlying blood pressure variations remain incompletely understood. MethodsLeveraging a well-characterized prospective population-based cohort comprised of 27,308 participants from the Singapore Chinese Health Study (SCHS), we evaluated genome-wide genetic associations for five blood pressure traits: hypertension status, systolic blood pressure, diastolic blood pressure, mean arterial pressure (MAP) and pulse pressure (PP). Additionally, we conducted a transcriptome-wide association study (TWAS), integrating gene expression data from 49 tissues, followed by colocalization and fine-mapping to prioritize regulatory genes. Association of identified variants with incident diabetes was additionally evaluated in the longitudinal data. ResultsWe validated 10 blood pressure loci (P between 1.64 x 10-20 - 4.10 x 10-8) and identified an East-Asian specific splice donor variant at the COL21A1 gene associated with PP (rs149344559, P = 6.78 x 10-10). Integrative analyses prioritized FGF5 in kidney cortex and ENPEP in pituitary tissue as candidate regulatory genes. The blood pressure-lowering allele at ENPEP (T allele, rs1879056) was associated with reduced risk of incident diabetes. Mediation analysis demonstrated that approximately 21% of the genetic association with diabetes was mediated through MAP (Pindirect-effect = 2 x 10-16). ConclusionThis study refines genetic predispositions for blood pressure among East-Asians. We further delineate tissue-specific regulatory pathways underlying blood pressure variations and identify ENPEP-mediated dysfunctions linking blood pressure genetics to diabetes risk, underscoring integrated disease mechanisms.

Sympathetic neuronal (SN) activity critically regulates the development and function of peripheral organs and tissues. Activity-dependent plasticity has been shown to modulate SN output, suggesting that compensatory forms of plasticity could contribute to maintaining stability of sympathetic circuits. Early SN hyperactivity drives the development of hypertension in humans and in the spontaneously hypertensive rat (SHR). In this study we used chemogenetic and pharmacological approaches, and took advantage of the enhanced activity of SHR SNs, to examine how long-term changes in activity impact synaptic properties in neonatal SN cultures. We showed that bidirectional changes in SN activity result in compensatory shifts in synaptic density that counteract long-term activity manipulations. These changes were mediated by satellite glial cells (SGCs), a non-neuronal cell in the sympathetic ganglia that has been shown to influence cholinergic synaptic sites during development. In the absence of SGCs there was no induction of homeostatic plasticity. Further, direct chemogenetic activation of SGCs was sufficient to drive compensatory plasticity, while glial inhibition blocked SN plasticity. We found that SGCs respond to cholinergic signaling by downregulating the expression of the synaptic regulators NGF and TNF, suggesting that neurons and glia interact to stabilize sympathetic output during long-term changes in circuit activity. Finally, we investigated whether these plasticity mechanisms are present in neonatal SHR SNs. We demonstrated that SHR SNs have an attenuated response to glia, both during synapse formation and activity-dependent plasticity. Taken together, this work outlines a novel homeostatic activity-dependent plasticity mechanism in the peripheral nervous system.

In the terminal segment of the seminiferous tubules, SOX17 expression in the rete testis (RT) epithelium plays a crucial role in the formation of the Sertoli valve (SV), as revealed by phenotypic analyses of RT-specific Sox17 conditional knockout (cKO) mouse testes. In these RT-specific Sox17 cKO testes, SV disruption leads to the backflow of RT fluid into the seminiferous tubules, resulting in defective spermiogenesis and male infertility. Although valve deformation in the Sox17 cKO testes is likely caused indirectly by impaired downstream actions of Sox17 in the RT, the mechanisms by which SOX17 in RT influences SV formation in the seminiferous tubules remain unclear. To address this, we generated a novel AMH-Sox17 transgenic (Tg) mouse line carrying a human AMH promoter-driven Sox17 cDNA cassette. We analyzed the phenotypes of the Sertoli valve and spermatogenesis in AMH-Sox17 Tg mice, as well as in RT-specific Sox17 cKO; AMH-Sox17 Tg double mutant mice. Ectopic SOX17 (SOX17+) expression in Sertoli cells resulted in excessive Sertoli valve structures with acetylated tubulin bundles in the terminal segment of the AMH-Sox17 Tg testes, along with enhanced WNT4/RSPO1 signaling, suggesting the enhanced valve formation of ectopic SOX17+ Sertoli cells by themselves. Moreover, the AMH-Sox17 Tg could partially rescue the SV deformation and infertility in RT-specific Sox17 cKO mice, leading to proper SV formation, normal spermiogenesis and a partial recovery of male fertility in AMH-Sox17 Tg; RT-specific Sox17 cKO double mutant mice. These findings genetically demonstrate that ectopic SOX17+ Sertoli cells can compensate for SOX17 paracrine signaling in the RT, underscoring a key shared downstream pathway between RT and SV. Summary statementThe paracrine actions downstream of ectopic SOX17 expression in the Sertoli cells not only promote the valve formation, but also partially rescue the defective spermiogenesis of the rete testis-specific Sox17-null mice.

BackgroundHypertension and preeclampsia are clinically distinct, yet biologically related conditions characterized by vascular dysfunction and elevated cardiovascular risk. Although genome-wide association studies (GWAS) have identified loci associated with blood pressure traits and preeclampsia, the functional mechanisms linking shared variants to gene regulation and clinical phenotypes remain unclear. MethodsWe integrated GWAS summary statistics for hypertension, systolic blood pressure (SBP), diastolic blood pressure (DBP), and preeclampsia to identify shared variants (p [&le;] 1x10-). Cis-expression quantitative trait loci (eQTL) analyses were performed in whole blood using RNA-seq data from 180 African American women. Significant associations (FDR [&le;] 0.05) were evaluated for replication across vascular, metabolic, and endocrine tissues in the Genotype-Tissue Expression (GTEx) project. Associations between gene expression and blood pressure traits were also assessed. ResultsWe identified 4,792 shared GWAS variants, of which 4,663 were tested in eQTL analyses, yielding 1,837 significant variant-gene associations across 78 genes. Replication in GTEx confirmed 645 associations involving 24 genes, many showing cross-tissue regulatory effects. Three genes (C4B, HLA-C, and HLA-DQB1) demonstrated convergent evidence across GWAS, gene regulation, and expression-trait analyses. C4B expression was positively associated with hypertension and SBP, while HLA-C showed consistent negative associations with hypertension, SBP, and DBP. HLA-DQB1 expression was specifically associated with DBP, suggesting trait-specific effects. ConclusionsThese findings highlight immune-related pathways as key mediators linking hypertension and preeclampsia. Integrating genetic, transcriptomic, and phenotypic data provides a framework for identifying functionally relevant loci and advancing mechanistic insights into cardiometabolic and pregnancy-related disorders. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=116 SRC="FIGDIR/small/26352450v1_ufig1.gif" ALT="Figure 1"> View larger version (35K): org.highwire.dtl.DTLVardef@1332b09org.highwire.dtl.DTLVardef@4e7c49org.highwire.dtl.DTLVardef@c1b980org.highwire.dtl.DTLVardef@799767_HPS_FORMAT_FIGEXP M_FIG C_FIG Shared genetic variants across hypertension, blood pressure traits, and preeclampsia converge on immune regulatory genes linking gene regulation to clinical phenotypes. GWAS summary statistics for hypertension, SBP, DBP, and preeclampsia were intersected to identify 4,792 shared variants, of which 4,663 were tested in cis-eQTL analyses in whole blood from 180 African American women (left). Shared variants regulate immune-related genes through cis-eQTL effects, yielding 1,837 associations involving 78 genes (FDR [&le;] 0.05). Three convergent genes emerged: C4B (upregulated), HLA-C (downregulated), and HLA-DQB1 (upregulated), with 645 associations involving 24 genes replicated across eight tissues in GTEx (center). Expression-trait analyses confirmed that C4B expression was positively associated with hypertension and SBP, HLA-C expression was negatively associated with hypertension, SBP, and DBP, and HLA-DQB1 expression was specifically associated with DBP. These genes implicate complement activation, antigen presentation, and adaptive immunity as shared mechanisms contributing to vascular dysfunction in both hypertension and preeclampsia. eQTL indicates expression quantitative trait locus; FDR, false discovery rate; GTEx, Genotype-Tissue Expression project; SBP, systolic blood pressure; DBP, diastolic blood pressure; APC, antigen-presenting cell; TCR, T-cell receptor; MHC, major histocompatibility complex.

Aims/hypothesisQuantitative nanoscale analysis of insulin secretory granules (ISGs) in human pancreatic tissue has been limited by the lack of imaging methods that combine high resolution with large-scale sampling. We aimed to establish expansion microscopy (ExM) as a platform for in situ, quantitative analysis of ISG organisation in human {beta}-cells and to assess whether type 2 diabetes (T2D) is associated with alterations in granule size, abundance or spatial organisation. MethodsWe applied Magnify ExM to PFA-fixed, paraffin-embedded pancreatic tissue sections from 6 human donors, 3 non-diabetic (ND) and 3 T2D, enabling super-resolution optical imaging of insulin-labelled granules. Insulin-positive structures were segmented and analysed using a morphometric pipeline to quantitatively assess size, shape and spatial features. Granule clustering was quantified based on combined area and roundness criteria. ResultsThe diameter distribution of highly circular granules was similar between ND and T2D samples and estimates of granule number per cell indicated only a modest reduction in T2D ([~]25%). In contrast, mapping insulin-positive structures in a roundness-area space revealed a marked enrichment of large, irregular objects consistent with granule clustering in T2D. The fraction of clustered granules was significantly increased in T2D and strongly inversely correlated with insulin stimulation index (r = -0.85). Conclusions/interpretationThese results establish expansion microscopy as a powerful platform for quantitative nanoscale analysis of human pancreatic tissue and identify altered spatial organisation of insulin granules, rather than marked granule depletion, as a prominent feature associated with {beta}-cell dysfunction in T2D. Research in contextO_ST_ABSWhat is already known about this subject?C_ST_ABSO_LI{beta}-cell dysfunction in type 2 diabetes is often attributed to reduced insulin content or {beta}-cell loss. C_LIO_LIInsulin secretory granules (ISGs) have been characterised ultrastructurally, but quantitative analysis in human tissue remains limited. C_LIO_LISuper-resolution approaches, including expansion microscopy, are emerging tools for nanoscale imaging in biological tissues. C_LI What is the key question?O_LIIs {beta}-cell dysfunction in type 2 diabetes associated with depletion of insulin granules or with altered spatial organisation? C_LI What are the new findings?O_LIInsulin granule size distribution is largely preserved in type 2 diabetes, with only a modest reduction in granule number per cell. C_LIO_LIA significant increase in insulin granule clustering is observed in diabetic {beta}-cells. C_LIO_LIGranule clustering is strongly inversely correlated with insulin secretion in the same donor tissues. C_LI How might this impact on clinical practice in the foreseeable future?O_LIIdentifying altered granule organisation as a feature of {beta}-cell dysfunction may help refine the understanding of disease mechanisms and guide future strategies targeting {beta}-cell function. C_LI

Background and ObjectiveSurgical complexity for renal tumors has traditionally been assessed using manual nephrometry scores, which require unreimbursed physician effort and are subject to interobserver variability. This study introduces an objective, fully automated alternative derived from decades of experience at a large academic center. MethodsWe trained a CT classification model to predict whether a patient would ultimately undergo Partial or Radical Nephrectomy (PN or RN). We hypothesized that the models confidence in RN (termed the CLARITY score) would serve as a surrogate for the difficulty of nephron-sparing approaches and thus for tumor complexity. This hypothesis was tested using multivariate logistic regression for failure to achieve trifecta, estimated blood loss (EBL) [&ge;] 500 mL, and length of stay [&ge;] 3 d. CLARITY was compared with tumor size and R.E.N.A.L. score. External validation in a geographically distinct cohort was performed. Key Findings and LimitationsFor predicting RN, CLARITY achieved an AUROC of 0.899 internally and 0.898 externally. In the external PN subgroup, it outperformed tumor size and R.E.N.A.L. score in predicting failure to achieve trifecta (AUROC 0.613), EBL [&ge;] 500 mL (0.727), and length of stay [&ge;] 3 d (0.673). In multivariable analysis, CLARITY remained associated with each outcome, whereas R.E.N.A.L. and size were not. This study is limited by its retrospective design. Conclusions and Clinical ImplicationsCLARITY is an automated CT-derived marker that quantifies renal tumor complexity more effectively than tumor size and R.E.N.A.L. score and may support scalable, objective preoperative complexity assessment. To support reproducibility and external validation, we have released a public inference pipeline and web-based DICOM upload portal for research use.