Biology subjects

Moledina, D. G.

Publications and source records attributed to Moledina, D. G..

4 recordsLinked to original sources

bioRxiv2025

Spatial Transcriptomics Identify T Cell-Driven Mechanisms of Kidney Damage in Immune Checkpoint Inhibitor-Associated Acute Interstitial Nephritis

IntroductionImmune checkpoint inhibitor-associated acute interstitial nephritis (ICI-AIN) is the most common finding on histopathology among patients with ICI-associated acute kidney injury (ICI-AKI). Patients with ICI-AIN often have T cell-dominant infiltration of the kidney and high tissue levels of CXCR3 ligands like CXCL9, 10, and 11; however, the mechanisms of inflammation in ICI-AIN are not well-understood. MethodsWe applied a sub-cellular spatial transcriptomics platform (Xenium Prime 5K) to compare the cellular composition of kidney biopsy tissue from patients with ICI-AIN with ICI-treated patients with acute tubular necrosis (ICI-ATN). ResultsAcross 8 kidney biopsy specimens (4 with ICI-AIN, 4 with ICI-ATN), we analyzed 332,000 cells, comprising kidney parenchymal cells and infiltrating immune cells. Using a spatially-aware cellular neighborhood-based classification, we identified cellular niches corresponding to each part of the nephron, in addition to unique fibrotic and inflammatory niches. Gene pathway analysis identified interferon-gamma (IFN-{gamma})/STAT1 signaling as strongly increased in ICI-AIN compared to ICI-ATN. While all inflammatory niches were overrepresented in ICI-AIN, CD8+ T cell infiltration and proinflammatory myeloid cells were the dominant immune niches. Spatial niche crosstalk analysis revealed that CD8+ T cell-derived IFN-{gamma} likely induced a proinflammatory program in myeloid cells, with increased production of CXCL9, 10, and 11. Furthermore, IFN-{gamma} signaling in ICI-AIN was associated with reduced oxidative phosphorylation in kidney tubular niches. ConclusionsSpatial transcriptomics reveal novel insights into key differences in the pathophysiology of ICI-AIN versus ICI-ATN. IFN-{gamma}-producing CD8+ T cells are likely key drivers of ICI-AIN and should be investigated as future therapeutic targets. Translational StatementSpatial transcriptomics may provide insight into differences in the cellular and spatial composition of immune checkpoint inhibitor-associated acute interstitial nephritis (ICI-AIN) and ICI-associated acute tubular necrosis (ICI-ATN). Using the novel Xenium 5K platform, we demonstrate that IFN-{gamma}-producing CD8+ T cells are central to the pathogenesis of ICI-AIN, and that CD8+ T cell-derived IFN-{gamma} likely induces a proinflammatory state in myeloid cells, with increased tissue production of CXCL9, 10, and 11. We then show that a reduction in oxidative phosphorylation and an IFN-{gamma}-driven influx of proinflammatory myeloid cells may further drive kidney damage in ICI-AIN. Many of these pathways represent potential druggable targets, and our findings may therefore inform future therapeutic approaches for ICI-AIN.

immunology↗

bioRxiv2025

Spatial analysis reveals the cellular microenvironments and mechanisms of inflammation and kidney injury in acute interstitial nephritis

Acute interstitial nephritis (AIN) causes 15-20% of all acute kidney injury cases but lacks effective therapies beyond corticosteroids. Using high-resolution imaging mass cytometry and single-cell spatial transcriptomics to analyze human kidney biopsies with AIN, non-immunologic acute tubular injury (ATI), and reference tissue, the CXCL9-CXCR3 axis was identified as the defining immunologic signature of AIN, with 44-fold higher predicted CXCL9-CXCR3 interactions than ATI, creating homotypic inflammatory T cell amplification networks concentrated in lymphoid aggregates. C3AR1+ immune cells were enriched in peritubular neighborhoods of complement 3-expressing injured tubule cells, predominantly VCAM1+ injured proximal tubules, linking tubular injury to immune activation in AIN. Nicotinamide phosphoribosyltransferase (NAMPT) was the strongest predictor of VCAM1+ tubular microenvironments, with expression by both injured tubules and surrounding immune cells coordinating metabolic-inflammatory niches. These findings reveal distinct molecular circuits underlying AIN pathogenesis and identify potential therapeutic targets for improving clinical management and preventing progression to chronic kidney disease.

immunology↗

bioRxiv2022

Immune-mediated Tubule Atrophy Promotes Acute Kidney Injury to Chronic Kidney Disease Transition

Incomplete repair after acute kidney injury (AKI) is associated with progressive loss of tubular cell function and development of chronic kidney disease (CKD). Here, we compared mice subjected to either unilateral ischemia-reperfusion kidney injury with contralateral nephrectomy (IRI/CL-NX, in which tubule repair predominates) or unilateral IRI with contralateral kidney intact (U-IRI, in which fibrosis and atrophy predominates) to investigate the mechanism(s) underlying transition to CKD following AKI. The initial injury and early recruitment and activation of macrophages, dendritic cells (DCs), neutrophils, and T cells were similar through day 7 but markedly diverged afterwards between the two models. By day 14, kidneys subjected to U-IRI had greater numbers of macrophages with higher expression of Ccl2, Ccl7, Ccl8, Ccl12, and Cxcl16. These chemokines correlated with a second wave of Ccr1-positive neutrophils and Cxcr6-positive T cells, resulting in a proinflammatory milieu, accompanied by increased expression of tubular cell injury, oxidative stress and major histocompatibility complex genes. This second wave of immune dysfunction led to a distinct profile of tubule injury with morphologic kidney atrophy and a decreased proportion of differentiated tubule cells. Combined depletion of neutrophils and T cells beginning on day 5 after U-IRI was found to reduce tubular cell loss and the associated kidney atrophy. In kidney biopsy samples from patients with AKI, the number of interstitial T cells and neutrophils negatively correlated with 6-month recovery of GFR. Together, our findings demonstrate that macrophage persistence after AKI promotes a T cell- and neutrophil-mediated proinflammatory milieu that leads to progressive tubule damage.

pathology↗

bioRxiv2022

Comparative evaluation of glomerular morphometric techniques reveals differential technical artefacts between FSGS and normal glomeruli

Morphometric estimates of mean glomerular volume (MGV) have clinical implications, over and above histologic data. However, MGV estimation is time-consuming, could waste tissue sections and requires expertise limiting its utility in retrospective clinical studies. MethodsWe evaluated MGV using both plastic and paraffin-embedded tissue from control and FSGS mice (n=10 each) using the gold-standard Disector/Cavalieri technique (Vglom-Cav) and other reported techniques [2- or 3-profile technique, Weibel-Gomez method (W-G)]. Within Vglom-Cav we examined the precision of MGV estimation while using MGVs obtained from 5- or 10-individual glomeruli measurements vs the true mean (20 glomeruli). ResultsIn both FSGS and controls, we identified an acceptable precision of 10-glomerular sampling vs true MGV within Vglom-Cav technique [88 (79-94) % of MGV obtained were within 10% of the true MGV]. The 5-glomerular sampling was less precise [70 (56, 81) % of MGV obtained were within 10% of true MGV]. In plastic based techniques, 2- or 3-profile MGVs showed greater concordance with Vglom-Cav, than W-G MGV. The new 3-profile technique offered incremental benefit to the existing 2-profile method (improved Lins concordance in control and FSGS animals). We observed a consistent reduction of Vglom values within control animals (52+/-0.06%) in paraffin-embedded tissue (vs corresponding methods in plastic) demonstrating a clear shrinkage artefact due to tissue processing. FSGS glomeruli showed significantly less and more variable shrinkage artefact likely due to glomerular fibrosis. ConclusionWe report the precision of 5- or 10-glomerular sampling for MGV estimation using controls and FSGS animals. We demonstrate and quantify the shrinkage bias in MGV during tissue processing for paraffin-embedding that also differentiated control animals and FSGS. Our findings have implications for experimental studies using glomerular morphometry.

pathology↗