JCI Insight

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.

Rationale: Preclinical familial pulmonary fibrosis (FPF) represents an early stage of fibrotic lung disease, yet the compartment- and cell-specific molecular programs preceding fibrosis remain poorly understood. Objective: To define spatially organized molecular signatures associated with preclinical FPF and identify tissue-informed circulating biomarkers linked to early fibrotic remodeling. Methods: We performed integrated multi-omic profiling of histologically preserved and remodeled lung regions from subjects with preclinical FPF, Idiopathic Pulmonary Fibrosis (IPF), and controls using spatial transcriptomics, single-nucleus RNA sequencing (snRNAseq), and blood proteomics. Differential expression and pathway enrichment analyses were performed across spatial compartments and epithelial cell states. Results: Histologically preserved lung regions in preclinical FPF demonstrated transcriptional abnormalities including stress-response, ciliary, and extracellular matrix-associated programs despite minimal architectural distortion. Spatial analyses identified alterations in alveolar niche molecular programs accompanied by increasing profibrotic signaling across preserved and tissue remodeled lung compartments. Compared with advanced IPF, preclinical FPF retained epithelial repair and surfactant-associated signatures. Integration with snRNAseq demonstrated enrichment of alveolar and airway epithelial cell dysregulated states associated with transitional phenotypes previously implicated in IPF. Compartment- and epithelial-associated transcriptional signatures identified in lung tissue were partially represented in the peripheral blood. Conclusion: Preclinical FPF is characterized by compartment- and cell-specific molecular programs that precede established fibrosis. We identified distinct alveolar, airway, and vascular molecular signatures and epithelial remodeling states represented in the peripheral blood. These findings provide an initial framework for molecular classification of early stages of pulmonary fibrosis and support future studies evaluating minimally invasive approaches for disease stratification and precision therapeutics.

Early complications following allogeneic hematopoietic stem cell transplantation (allo-HSCT), including graft-versus-host disease (GVHD) and viral reactivation, remain major causes of post-transplant morbidity, but whether immune perturbations precede these events remains unclear. We performed longitudinal TCR{beta} repertoire profiling in 108 allo-HSCT recipients and their corresponding donors at baseline and three early post-transplant time points to characterize immune reconstitution dynamics. Reduced baseline TCR diversity was most strongly associated with subsequent Epstein-Barr virus (EBV) reactivation, whereas cytomegalovirus (CMV) reactivation was more closely linked to post-transplant repertoire remodeling characterized by clonal expansion and reduced donor-recipient repertoire similarity. Sequence-based predictive modeling demonstrated meaningful discrimination, with fusion models achieving area under the curve (AUC) values of 0.745 for CMV, 0.819 for EBV, and 0.834 for GVHD. Temporal analyses further revealed complication-specific predictive windows. These findings indicate that major post-transplant complications are preceded by detectable immune perturbations and support the potential utility of TCR repertoire monitoring for early risk stratification after transplantation.

Blood flow restriction exercise (BFR-E) has gained popularity as a therapy used to improve muscle mass and strength in various clinical populations. However, the systemic and intramuscular responses to BFR-E are widely unknown. Here, we describe the functional and metabolic responses to BFR-E in our novel in vivo method of BFR-E in rats. Implementation of the model revealed increase in muscle mass and maximal strength in rats exposed to chronic BFR-E. Systemic metabolites related to glycolysis and redox metabolism were altered following acute BFR-E and metabolites related to amino acids and the TCA cycle were altered following chronic BFR-E. Moreover, transcriptomic analysis revealed a muscle-specific metabolic response to chronic BFR-E that coincided with morphological adaptations. Given the broad application of BFR-E in the rehabilitative setting, we examined the acute, systemic response to BFR-E in post-surgical human subjects. Semi-targeted metabolomic analysis revealed no significant alterations in circulating metabolites following acute BFR-E in humans, mirroring findings in acutely exercised rats. Together, these results suggest that the benefits of BFR-E are not mediated by acute systemic metabolic perturbations but instead arise from tissue-specific adaptations that develop with repeated exposure, establishing a conserved, translational framework for mechanistic investigation.

ObjectivesLupus nephritis (LN) is a severe complication of systemic lupus erythematosus with heterogeneous clinical outcomes and limited therapeutic options. Although immune dysregulation is central to LN pathogenesis, the underlying cell-type-specific regulatory mechanisms and their genetic determinants remain poorly characterized. MethodsWe generated a single-cell multi-omics atlas of peripheral blood mononuclear cells (PBMCs) from newly diagnosed, minimally treated LN patients by integrating single-cell RNA-seq (scRNA-seq) and single-nucleus ATAC-seq (snATAC-seq) profiles. To elucidate genetically driven regulatory programs in a broaden LN population, we generated a blood expression quantitative trait loci (eQTL) atlas from 99 Chinese LN patients and performed Bayesian colocalization analysis to systematically prioritize putative causal genes for LN. Finally, we investigated how fine-mapped SNPs associated with LN phenotypic manifestations exert regulatory effects within distinct single-cell chromation contexts by leveraging peak-to-gene linkages at single-cell resolution. ResultsOur single-cell multi-omic dataset and orthogonal analytical approaches revealed extensive immune remodeling in LN, characterized by amplified innate immune activation and impaired adaptive immune responses, and identified transcription factors (TFs) orchestrating immune regulatory circuits. Bayesian colocalization analysis nominated 14 high-fidelity causal genes for kidney function and 23 for SLE. Integration with fine-mapped GWAS variants highlighted critical cell type convergence across autoimmune disorders and immune-mediated nephropathies, particularly within B cell subsets, where TF-driven programs delineated stage-specific differentiation networks. ConclusionsTogether, these analyses reconstruct the regulatory architecture underlying immune dysregulation in LN and connect genetic variation to cell-type-specific regulation, guiding genetically informed therapeutic development.

ObjectivesLupus nephritis (LN) is a severe complication of systemic lupus erythematosus (SLE), leading to progressive renal fibrosis and functional decline. Understanding the interplay between immune cells and stromal cells is needed to develop effective therapeutic strategies. Here, we investigated the landscape of macrophage-fibroblast interactions in human LN and validated these findings in mouse models. MethodsWe characterized distinct fibroblast subsets and their interactions with renal macrophages using single-cell RNA sequencing (scRNAseq) of 156 human LN biopsies and 30 healthy controls from the AMP-SLE cohort, and spatial transcriptomics of biopsies from 6 LN patients. In vitro co-culture studies using mouse models were performed to further define functional consequences of these interactions. ResultsWe identified two myofibroblast subsets: a pro-inflammatory subset (Myofib1) enriched in the tubulointerstitium, and a fibrotic/remodeling subset (Myofib2) in glomeruli, both correlating with the histologic chronicity index. Spatial transcriptomics revealed different colocalization patterns, with Myofib1 interacting with activated resident macrophage (RM) subsets and Myofib2 with glomerular infiltrating disease-associated macrophages. In vitro co-culture studies demonstrated that nephritic RMs promote a pro-inflammatory, remodeling fibroblast phenotype that impairs wound healing and drives a Myofib1-like gene program, whereas disease-associated macrophages generated profibrotic fibroblasts with dysregulated reparative capacity. Cell-cell communication analyses identified key ligand-receptor interactions mediating this crosstalk, including Spp1/integrins, Sema4/PlexinB, and NAMPT/INSR. ConclusionsOur data reveal a spatially and functionally heterogeneous landscape of macrophage-fibroblast crosstalk in LN. These findings advance our understanding of renal fibrogenesis in LN, highlighting specific fibro-inflammatory circuits that may represent therapeutic targets to prevent chronic renal damage.

Glioblastoma Multiforme (GBM) is a highly aggressive brain cancer characterized by rapid proliferation and extensive remodeling of the extracellular matrix (ECM), leading to progressive tissue stiffening. Although ECM stiffness is known to promote GBM progression, the molecular mechanisms linking mechanical cues to tumor growth remain insufficiently defined. In this study, transcriptomic comparison of GBM tumors and non-neoplastic brain tissue revealed coordinated upregulation of cell cycle regulators and matrisome-associated genes, with survivin (BIRC5) identified as a central node linking proliferative signaling and ECM remodeling networks. Analysis of GBM patient specimens further showed strong nuclear survivin expression in regions with elevated collagen deposition. To directly evaluate stiffness-dependent regulation of survivin, GBM cells were cultured on fibronectin-infused hydrogels with tunable stiffness. Stiff matrices increased survivin expression along with cyclin D1 and cyclin A, consistent with increased cell cycle progression. Pharmacologic inhibition or siRNA-mediated suppression of survivin reduced stiffness-induced proliferation and attenuated expression of matrisome components, including collagens and lysyl oxidase. These findings indicate that survivin functions as a mechanosensitive regulator that coordinates cell cycle progression with ECM production in stiff tumor microenvironments. Collectively, this study identifies survivin as a key mediator linking ECM stiffness to GBM growth and matrisome remodeling. Targeting survivin and its effectors may offer a mechanosensitive strategy to limit GBM growth.

Idiopathic pulmonary fibrosis (IPF) is an age-related, progressive, and fatal interstitial lung disease for which effective therapies remain limited. Alveolar type 2 (AT2) epithelial cells serve as facultative stem cells essential for alveolar repair; however, AT2 cell senescence disrupts epithelial regeneration and contributes to fibrotic remodeling in IPF. Syndecan-1 is a transmembrane heparan sulfate proteoglycan predominantly expressed by lung epithelial cells, but its role in AT2 dysfunction during fibrosis is poorly defined. Here, we demonstrate that syndecan-1 is robustly upregulated in AT2 cells in IPF and other fibrotic lung diseases, as well as in murine bleomycin-induced lung fibrosis. Syndecan-1 expression was further enhanced with aging and associated with increased fibrotic burden in aged mice. Using integrated human transcriptomic analyses, mouse genetic models, and epithelial cell-based systems, we show that excess syndecan-1 promotes cell-autonomous epithelial senescence and impairs AT2 progenitor function. Elevated syndecan-1 reduced AT2 renewal capacity, disrupted differentiation, and diminished surfactant protein C level, whereas genetic loss of syndecan-1 attenuated senescence and preserved epithelial function following injury. Together, these findings identify syndecan-1 as a critical epithelial regulator of AT2 senescence and maladaptive repair in pulmonary fibrosis and support targeting syndecan-1-driven epithelial dysfunction as a potential therapeutic strategy.

Patients with idiopathic pulmonary fibrosis (IPF) are highly vulnerable to respiratory virus infections, but the cellular mechanisms linking fibrotic remodeling to impaired local antiviral defense remain unclear. Here, we investigated how cellular senescence shapes the response of patient-derived healthy and IPF primary lung fibroblasts to influenza A virus (IAV) infection. Transcriptomic profiling identified infection as the driver of gene expression in both DNA damage-induced senescent healthy and IPF fibroblasts and revealed induction of canonical antiviral pathways in both cell states. However, senescent IPF fibroblasts adopted a distinct antiviral response state characterized by a broader set of uniquely induced genes and differential coordination of antiviral transcriptional networks. Functionally, senescence increased viral titers in healthy and IPF fibroblasts, while senescent IPF fibroblasts displayed an altered inflammatory response. Network analysis linked viral response- and cell cycle-associated modules specifically to the senescent healthy infected state, whereas these programs were weaker in senescent IPF fibroblasts. Transcription factor inference identified IRF3 and STAT1 as candidate regulators of this altered antiviral state in both senescent healthy and IPF fibroblasts. Consistent with the network and transcription factor analyses, siRNA-mediated depletion of IRF3 or STAT1 significantly reduced IFN-{beta} secretion in senescent healthy fibroblasts, whereas IPF fibroblasts showed only milder effects, indicating a disease-specific dependence on these pathways for antiviral control. Together, these findings show that the combination of cellular senescence and fibrotic fibroblast identity creates a dysfunctional antiviral state that may help explain the high susceptibility of IPF patients to virus-associated acute exacerbations and disease worsening.

Duchenne muscular dystrophy (DMD) is a multisystem disorder affecting striated muscle, metabolism, and the central nervous system (CNS). Although glucocorticoids remain the standard therapy, muscle-centric evaluations typically fail to capture how dosing regimen and compound selection affect CNS and metabolic phenotypes. Here, we compared daily and weekly dosing of prednisolone and vamorolone in juvenile mdx mice over six weeks to determine how these variables influence multisystem outcomes. Multiorgan efficacy and adverse effects were quantified across behavioural, endocrine, metabolic, cardiovascular, and muscle domains using behavioural assays, in vivo and functional muscle testing, haemodynamic evaluation and histopathology. Daily glucocorticoid dosing failed to improve muscle function or strength, whereas weekly vamorolone produced the most robust improvements in functional and in vivo muscle strength. Daily prednisolone reduced circulating creatine kinase levels, but this biochemical change did not translate into enhanced muscle function outcomes. Daily regimens also induced severe adrenal cortical atrophy, yet these endocrine alterations were dissociated from CNS stress and anxiety responses, which remained unchanged by treatment. In addition, daily dosing caused pronounced systemic metabolic consequences, whereas weekly regimens substantially attenuated these effects, identifying dosing frequency as a key determinant of safety. Together, these findings demonstrate that glucocorticoid regimen selection fundamentally reshapes the efficacy-adverse effect profile and underscores the value of integrated multiorgan evaluation in DMD. This work highlights the need to expand therapeutic assessments beyond muscle pathology and raises new questions about how glucocorticoid signalling differentially engages peripheral and central physiological systems.

Lupus nephritis (LN) is a leading cause of morbidity in pediatric systemic lupus erythematosus (pSLE) due to suboptimal kidney remission rates and the sequelae of prolonged intensive immunosuppressive therapy. LN is patchy, with some glomeruli severely damaged while others remain histologically unaffected in the same kidney. Using spatial transcriptomic technology, we interrogated microanatomic transcriptional differences between histologically damaged and unaffected glomeruli in pSLE LN to understand local drivers of renal injury. Despite SLE being a disease of Type I interferon (IFN), IFN gene response does not associate with local glomerular damage. Rather, damage associates with a transcriptional module of higher expression of myeloid cell markers, C5AR1 (encoding the receptor for complement component 5a [C5a]), early complement components, and fibrosis genes. Bulk RNA-sequencing of C5a stimulated human monocyte-derived-macrophages revealed upregulation of tissue-remodeling and fibrosis-related pathways reversible by the C5aR1 inhibiting drug avacopan. These same C5a-inducible fibrosis genes were significantly upregulated in histologically damaged versus unaffected LN glomeruli providing a mechanistic link between C5a-C5aR1 signaling and early fibrosis in proliferative lupus nephritis. Our data provide insight into an understudied connection between complement activation and fibrosis relevant in SLE and likely other inflammatory diseases of complement activation.

Pulmonary fibrosis (PF) involves excessive collagen accumulation, yet mechanisms shifting the balance of synthesis and degradation toward net deposition remain unclear. Myeloperoxidase (MPO) inversely correlates with survival in PF. Using the bleomycin model, we found MPO knockout (MPOko) mice were protected from fibrosis, and pharmacological MPO inhibition after peak inflammation (day 7) recapitulated this protection. MPO persisted in lung tissue 21 days post-injury despite neutrophil efflux, linking acute inflammation to sustained remodeling. Mechanistically, we identified that MPO inhibits Cathepsin K (CatK), a potent collagenolytic enzyme involved in fibrosis resolution. Notably, CatK gene expression (CTSK) is elevated in PF, suggesting post-translational inhibition of CatK. MPOko and inhibitor-treated mice exhibited elevated CatK activity after bleomycin; exogenous addition of pathophysiologic concentrations of MPO reduced CatK activity in mouse precision-cut lung slices and human fibroblasts. Biochemically, MPO reduced CatK activity to 33% of control. In two distinct cohorts of PF patients, we observed significantly increased MPO protein levels in platelet poor plasma and in lung tissue. In PF patients, 62% had MPO levels in platelet poor plasma exceeding healthy controls, while lung tissue from other PF patients showed significantly elevated MPO staining. Plasma levels were inversely correlated with decreased survival, FVC, and DLCO. These findings establish MPO as a post-translational inhibitor of CatK-mediated collagenolysis, revealing a mechanism linking acute inflammation to sustained fibrosis and suggest a patient subpopulation that may benefit from MPO-targeted therapy. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=54 SRC="FIGDIR/small/713467v1_ufig1.gif" ALT="Figure 1"> View larger version (17K): org.highwire.dtl.DTLVardef@e099e1org.highwire.dtl.DTLVardef@196a40dorg.highwire.dtl.DTLVardef@ec7f6eorg.highwire.dtl.DTLVardef@a227d9_HPS_FORMAT_FIGEXP M_FIG C_FIG Myeloperoxidase persists in lung tissue after injury and inhibits cathepsin K activity, impairing collagen degradation and promoting extracellular matrix accumulation during pulmonary fibrosis.

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.

Recovery of hand and arm function is critical for improving quality of life in individuals with tetraplegia due to spinal cord injury (SCI). Nerve transfer procedures can restore meaningful hand and arm function in chronic SCI, yet postoperative outcomes vary widely. We conducted a prospective, single-arm, open-label trial to assess the impact of intensive, robot-assisted rehabilitation training on functional recovery and cortical reorganization following nerve transfer. The primary endpoint was assessment of hand and arm function measured by the Box and Blocks Test. We report the results from three participants, AIS A at enrollment, who completed six weeks of intensive robotic training at least 1 year after nerve transfer surgery (NCT04041063). All participants demonstrated minimally important difference improvements in at least one secondary clinical outcome. These improvements were accompanied by cortical reorganization measured by transcranial magnetic stimulation motor mapping, indicating integration of the newly established peripheral motor pathways. No serious adverse events related to surgery or rehabilitation occurred. Although recruitment was limited by the COVID-19 pandemic and precludes definitive conclusions regarding efficacy, these findings suggest that standardized, intensive robotic rehabilitation may enhance functional outcomes after nerve transfer surgery for chronic tetraplegia.

Background: Pathologic aldosteronism induces oxidative stress, tissue injury, and increases in hemoglobin. Conversely, aldosterone antagonist therapy decreases hemoglobin. Whether these effects are attributable to aldosterone-mediated changes in iron and oxygen metabolism is unknown. Methods: The plasma proteome of participants with overt primary aldosteronism (PA) (n=50) was compared with participants without overt PA (n=61). To isolate aldosterone-dependent effects, participants without overt PA underwent oral sodium suppression testing to quantify the magnitude of renin-independent aldosterone production, enabling monotonic dose-response analyses across the continuum of renin-independent aldosteronism (subclinical to overt PA). Differential abundance testing was performed using empirical Bayes linear modeling, followed by Reactome pathway enrichment analysis and covariate-adjusted sensitivity analyses. To validate clinical relevance, aldosterone dose-response trends with blood count parameters were examined in this cohort, and an independent population-based cohort of 5,713 people with hypertension. Results: 903 proteins in the peripheral circulation were differentially abundant in overt PA versus participants without PA. The most significantly increased protein in overt PA was CYBRD1, involved in iron reduction and absorption. Pathway enrichment identified 16 iron- and heme-related pathways, including erythropoietin signaling, heme biosynthesis and mitochondrial iron-sulfur cluster biogenesis, with increases in heme and erythroid proteins and decreases in mitochondrial iron-sulfur proteins. Linear aldosterone dose-dependent trend analyses across the PA continuum further supported this signature, identifying progressive increases in hemoglobin subunits (HBA1/HBB), heme-related proteins (HMBS, UROS, AMBP, HPX, GLO1) and erythrocyte oxygen handling enzymes (CA1/CA3), alongside progressive reductions in mitochondrial electron transport chain subunits (CYCS, ETFA). These proteomic changes corresponded with aldosterone dose-dependent increases in red blood cell count, hemoglobin, and hematocrit, in this cohort and another population-based cohort. Conclusion: The continuum of PA is characterized by a progressive shift away from mitochondrial oxidative phosphorylation and toward increased intestinal iron absorption, preferential iron transport over storage, and enhanced heme synthesis and recycling, possibly reflecting cellular pseudohypoxia and systemic adaptations to increase oxygen delivery. These findings provide a novel mechanistic basis for aldosterone-mediated tissue injury and the benefits of aldosterone-directed therapy.

Nephronophthisis (NPH) is n rare recessive kidney disease caused by biallelic variants in more than 25 NPHP genes encoding proteins that localize to primary cilia. It is characterized by three different forms depending on the age of onset and kidney lesions: infantile (cystic), juvenile/late onset (fibrotic). To date, the pathways linking altered primary cilia function to progressive kidney scarring in NPH remain poorly defined and therapeutic options are lacking. To address these questions, we generated two new mouse NPH models by inactivating Nphp3 specifically in kidney tubules either during embryogenesis or in adult, recapitulating the infantile and juvenile forms of the disease, respectively. Embryonic inactivation produced a rapid and severe cystic phenotype with tubular dedifferentiation, progressive interstitial fibrosis, inflammation and kidney failure, while postnatal inactivation led to a slowly progressive tubulointerstitial nephropathy characterized by tubular atrophy, fibrosis and immune cell infiltration without cyst formation. Strikingly, cilia were preserved in the early stages of both models, indicating that ciliogenesis impairment is not a primary driver of NPH3 pathogenesis. Transcriptomic profiling of the juvenile model revealed that disease initiation is driven by mitochondrial dysfunction, innate immune activation and aberrant cell cycle progression, while epithelial-to-mesenchymal transition and Wnt/{beta}-catenin remodelling emerges only at later stages of disease progression. Therapeutic intervention with the PGE1 (alprostadil) failed to rescue the cystic/infantile model but significantly attenuated fibrosis, inflammation and interstitial fibrosis in the fibrotic/juvenile model. The ability to recapitulate both disease forms through temporal modulation of gene inactivation suggests that primary cilia serve distinct, stage-specific functions in kidney tubular homeostasis, with different cellular processes being selectively vulnerable depending on the causative gene or variant. Collectively, these findings uncover early pathogenic mechanisms that may constitute tractable therapeutic targets for the treatment of nephronophthisis.

Spinal muscular atrophy (SMA) is caused by insufficient levels of the survival motor neuron (SMN) protein and clinically manifests as profound weakness due to motor neuron degeneration. While recent evidence suggests it is a multisystem disorder, the pathological programs in neural and peripheral tissues are poorly understood. We applied spatial transcriptomics to cross-sections from the entire lumbar region of pre-symptomatic SMA and control mice to define early, tissue-wide transcriptional consequences of SMN deficiency. This approach enabled spatially preserved analysis of spinal cord, dorsal root ganglia, muscle, bone, cartilage, bone marrow, adipose, and connective tissues within their native anatomical context. Within the SMA spinal cord, motor neuron associated regions and ventral interneurons exhibited upregulation of neurofilaments, tubulin isoforms, and microtubule transport machinery. Neurofilament changes were largely restricted to motor neurons, and tubulin dysregulation extended broadly across ventral regions. Multiple tissues displayed collagen and extracellular matrix gene dysregulation at post-natal day 4. Skeletal muscle demonstrated fiber type-specific stress responses, including induction of atrophy-associated genes, while bone displayed an osteoclast-dominant transcriptional signature, consistent with accelerated resorption and a pro-osteoporotic state. Bone marrow transcriptomes indicated activation of neutrophil degranulation, innate immune signaling, and osteoclastogenic pathways, identifying bone marrow as an active inflammatory and skeletal regulatory niche in SMA. Adipose tissue exhibited extracellular matrix dysregulation, complement activation, profibrotic TGF-{beta} signaling, and stress-induced lipolysis. These findings reveal that SMN deficiency drives early transcriptional reprogramming across multiple tissues well before motor neuron loss and identify non-neuronal pathological programs that offer therapeutic targets for improving long-term outcomes in SMA.

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.

Juvenile dermatomyositis (JDM) is a chronic multisystem vasculopathy and inflammatory myopathy characterized by proximal muscle weakness, distinct rash, and risk of complications such as calcinosis cutis, skin ulceration, and mortality. Molecular insight from diagnostic muscle biopsy histology is limited, and the mechanistic pathoetiology of JDM remains poorly defined. We used single nuclei transcriptomics to assess muscle samples from patients with newly diagnosed treatment-naive JDM. As a control, we assessed muscle samples from patients with congenital (nemaline) myopathy (CM), a non-inflammatory disorder. A total of 25,794 high quality nuclei were analyzed and clustered into various muscle-resident or infiltrating cellular populations. JDM tissue was characterized by an enriched interferon (IFN) response signature across endothelial, stromal, and immune cell compartments. Endothelial and perivascular populations showed increased inflammatory and angiogenic programs. Intercellular communication inference analysis identified dysregulated vascular endothelial growth factor (VEGF)-related signaling involving endothelial, stromal, and myonuclear populations as a possible mechanism for myonuclear-driven modulation of the muscle microvasculature. Spatial RNA in situ hybridization supported increased expression of selected IFN responsive and angiogenesis signaling genes in JDM tissue. Collectively, these data provide a cell type-resolved view of treatment-naive JDM muscle and highlight vascular and IFN pathways for follow-up in larger cohorts.

Kawasaki disease (KD) is an acute pediatric vasculitis characterized by dysregulated host immune responses and risk of coronary artery injury. Although a two-transcript IFI27-MCEMP1 axis has been clinically validated to distinguish KD from other febrile illnesses, the long noncoding RNA (lncRNA) context of this interferon-myeloid imbalance remains incompletely understood. We evaluated whether peripheral blood mononuclear cell (PBMC)-derived lncRNAs are altered in KD and associated with the interferon and myeloid components of the IFI27-MCEMP1 transcriptomic axis. Children younger than 8 years with suspected KD were prospectively enrolled at the Children's Hospital of Fudan University from 2024 to 2025. The newly enrolled cohort included 55 children with KD and 48 febrile controls. For integrated immune-transcript association analyses, these data were combined with two previously characterized same-site cohorts, yielding 188 children with KD and 175 febrile controls. Expression of IFI27, MCEMP1, CHROMR, MALAT1, and NEAT1 was measured by reverse transcription quantitative PCR and normalized to GAPDH using {Delta}Ct values. In the newly enrolled cohort, the IFI27-MCEMP1 axis reproduced discrimination between KD and febrile controls, with an area under the receiver operating characteristic curve of 0.88; performance was similar in the integrated cohort, with an area under the curve of 0.89. In PBMC lncRNA analyses, CHROMR and MALAT1 {Delta}Ct values were significantly higher in KD than in febrile controls, indicating lower relative expression, whereas NEAT1 did not show a significant KD-specific differential-expression signal. CHROMR showed the strongest association with the IFI27 interferon-associated component, while MALAT1 showed weaker but directionally informative associations with both IFI27 and MCEMP1, including an inverse association with MCEMP1. These findings support an lncRNA-associated interferon-myeloid immune architecture in KD, marked by coordinated attenuation of IFI27, CHROMR, and MALAT1 together with increased MCEMP1. This PBMC RNA pattern provides a biologically interpretable framework for KD immune dysregulation and generates testable hypotheses regarding RNA-regulatory programs in KD vasculitis.