Biology subjects

Wiech, T.

Publications and source records attributed to Wiech, T..

9 recordsLinked to original sources

bioRxiv2026

Intracellular complement Factor B couples inflammatory sensing to metabolism, chromatin regulation and maladaptive tissue repair

Inflammatory signals are broadly conserved, yet how tissue context converts them into programs of recovery or maladaptive repair remains unclear. Using kidney injury as a model of inflammation-to-repair transitions, we identify an injury-induced proximal-tubule complement program in which cell-intrinsic complement proteins are repurposed across subcellular compartments to couple inflammation to metabolic and chromatin regulation and promote maladaptive fibrotic remodeling. Mechanistically, myeloid-derived IL-1b; signals through IL-1R1 on injured tubular cells to recruit NF-kB and AP-1 to C3 and Cfb, coordinately inducing complement component 3 (C3) and Factor B (FB). Cytoplasmic FB drives cleavage-activation of cell-intrinsic C3, which supports tubular cell mitochondrial metabolic adaptation to stress and accumulation of C3aR-expressing macrophages around injured tubules. Nuclear FB, on the other hand, binds chromatin through a previously unrecognized DNA-binding interface and mediates histone H3 proteolysis and the preferential remodeling of chromatin promotors enriched in transcriptional programs relevant to maladaptive repair. Key features of this injury-associated C3-FB response, including intranuclear FB, are conserved in human kidney disease, associate with kidney dysfunction, and distinguish diseased from healthy kidneys. Together, these findings suggest that extracellular complement-targeting therapies may miss disease-relevant intracellular functions and suggest nuclear FB as a distinct target whose chromatin interaction and processing capacity could selectively limit maladaptive tissue responses beyond conventional inhibition.

immunology↗

bioRxiv2025

Spatial Analysis of T Cell Clonality in Autoimmune Kidney Disease Using TRV Probes

Hypothesizing that the localization of T cell clones correlates with immune function, our goal was to develop an unbiased method to study the spatial distribution of T cells in tissues. We created an in situ hybridization panel with 248 probes that identify immune and tissue cell types, and 132 probes for all variable TRAV, TRBV, TRGV, and TRDV gene segments. Applying this approach to analyze renal biopsies from patients with autoimmune kidney disease, combinations of TRV segments provided spatial information about T cell clonality. Confined clusters of clonally related {beta} T cells were found in proximity to increased numbers of antigen-presenting cells, B cells, and other T cells, reflecting local immune cell interactions. {gamma}{delta} T cells were more frequently located outside or at their periphery of T cell infiltration areas. In conclusion, integrating spatial information with TCR clonotype analysis provided new insights into the organization of immune responses at the tissue level.

immunology↗

bioRxiv2024

Spatio-temporal interaction of immune and renal cells determines glomerular crescent formation in autoimmune kidney disease

Rapidly progressive glomerulonephritis (RPGN) is the most aggressive group of autoimmune kidney disease with the worst prognosis. Anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitis, anti-glomerular basement membrane (anti-GBM) and lupus nephritis are the most common causes of RPGN and are characterized by the formation of glomerular crescents and infiltration of leukocytes that eventually lead to glomerulosclerosis and kidney failure. In this work, we used high-resolution spatial transcriptomics of 32 ANCA, 19 lupus nephritis, 6 anti-GBM, and 6 control patients to understand how intercellular signaling between immune and renal tissue cells leads to renal inflammation and glomerular injury. Using 3,218,210 immune and kidney cells, we observed that the biological pathways involved in the sequence of glomerular crescent formation are similar across the diseases. While innate immune cells infiltrated the glomerular compartment relatively early, later increases in adaptive immune cells were largely restricted to the periglomerular regions. These changes in immune cells temporally correlated with increases in glomerular parietal epithelial (PEC) and fibrotic mesangial cells, suggesting disease-relevant functional signaling between these immune and renal cells. Cell communication analysis revealed early disease PDGF signaling from epithelial and mesangial cells to PECs, causing their activation and proliferation. At later stages, TGF-{beta} signaling from macrophages, T cells, epithelial cells, and mesangial cells to PECs triggered the expression of extracellular matrix components resulting in glomerulosclerosis. Our results highlight a spatio-temporally conserved progression into glomerular crescents and sclerosis for ANCA, lupus nephritis, and anti-GBM disease, which is driven by consecutive PDGF and TGF-{beta} signaling to PECs.

immunology↗

bioRxiv2024

The Regulation of MAGI2 and its Diagnostic Application in Podocytopathies

Podocyte dysfunction is central to various glomerular diseases, necessitating reliable biomarkers for early detection and diagnosis. This study investigates the regulatory mechanisms of membrane-associated guanylate kinase inverted 2 (MAGI2) and its potential as a biomarker for podocytopathies. The expression of the gene coding for the scaffolding protein MAGI2 was examined across four species and demonstrated to be conserved within the podocyte filtration slit. In vitro and in vivo studies using isolated glomeruli and mammalian animal models of glomerular disease, including DOCA-salt hypertension, nephrotoxic serum nephritis, and puromycin aminonucleoside nephropathy, demonstrated significant downregulation of MAGI2 in injured podocytes. This downregulation was also conserved in a zebrafish model of focal and segmental glomerulosclerosis (FSGS), and the podocyte-specific MAGI2 ortholog Magi2a was reduced post podocyte injury. CRISPR/Cas9-generated zebrafish mutants for magi2a exhibited marked glomerular filtration barrier defects and downregulation of nephrin, underscoring MAGI2s critical role in podocyte function. Human biopsy analyses revealed differential MAGI2 expression: it was increased in minimal change disease (MCD) patients but significantly decreased in primary, but not secondary FSGS cases. As MAGI2 localization did not change in disease states it is an alternative marker for super-resolution microscopy-based morphometry of the filtration slit, correlating with nephrin-based measurements. These findings highlight the potential of MAGI2 as a sensitive biomarker for podocyte injury and its diagnostic utility in differentiating between primary FSGS and MCD.

cell biology↗

bioRxiv2024

Podocyte exopher-formation as a novel pathomechanism in membranous nephropathy

BackgroundMembranous nephropathy (MN) is caused by autoantibody binding to podocyte foot process antigens such as THSD7A and PLA2R1. The mechanisms of the glomerular antigen/autoantibody deposition and clearance are unknown. MethodsWe explore the origin and significance of glomerular accumulations in (1) diagnostic and follow-up biospecimens from THSD7A+ and PLA2R1+-MN patients compared to nephrotic non-MN patients, and (2) in experimental models of THSD7A+-MN. ResultsWe discovered podocyte exophers as correlates of histological antigen/autoantibody aggregates found in the glomerular urinary space of MN patients. Exopher vesicle formation represents a novel form of toxic protein aggregate removal in Caenorhabditis elegans neurons. In MN patients, podocytes released exophers to the urine. Enrichment of exophers from MN patient urines established them as a glomerular exit route for antigens and bound autoantibody. Exophers also carried disease-associated proteins such as complement and provided a molecular imprint of podocyte injury pathways. In experimental THSD7A+-MN, exophers were formed from podocyte processes and cell body. Their formation involved the translocation of antigen/autoantibody from the subepithelial to the urinary side of podocyte plasma membranes. Urinary exopher-release correlated with lower albuminuria and lower glomerular antigen/autoantibody burden. In MN patients the prospective monitoring of urinary exopher abundance and of exopher-bound autoantibodies was additive in the assessment of immunologic MN activity. ConclusionsExopher-formation and release is a novel pathomechanism in MN to remove antigen/autoantibody aggregates from the podocyte. Tracking exopher-release will add a non-invasive diagnostic tool with prognostic potential to clinical diagnostics and follow-up of MN patients.

cell biology↗

bioRxiv2022

Single-cell transcriptomics reveals a mechanosensitive injury signaling pathway in early diabetic nephropathy

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease and histopathologic glomerular lesions are among the earliest structural alterations of DN. However, the signaling pathways that initiate these glomerular alterations are incompletely understood. To delineate the cellular and molecular basis for DN initiation, we performed single-cell and bulk RNA sequencing of renal cells from type 2 diabetes mice (BTBR ob/ob) at the early stage of DN. Analysis of differentially expressed genes revealed glucose-independent responses in glomerular cell types. The gene regulatory network upstream of glomerular cell programs suggested the activation of mechanosensitive transcriptional pathway MRTF-SRF predominantly taking place in mesangial cells. Importantly, activation of MRTF-SRF transcriptional pathway was also identified in DN glomeruli in independent patient cohort datasets. Furthermore, ex vivo kidney perfusion suggested that the regulation of MRTF-SRF is a common mechanism in response to glomerular hyperfiltration. Overall, our study presents a comprehensive single-cell transcriptomic landscape of early DN, highlighting mechanosensitive signaling pathways as novel targets of diabetic glomerulopathy.

molecular biology↗

bioRxiv2022

Transcriptional and clonal characterization of cytotoxic CD8+ T cells in crescentic glomerulonephritis

Crescentic glomerulonephritis (cGN), most often caused by anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis, is an aggressive form of immune-mediated kidney disease and represents an important cause of end-stage renal failure. Although it is known that T cells infiltrate the kidney in cGN, their precise role in autoimmune kidney disease remains to be fully elucidated. By performing single-cell analysis, we identified activated, clonally expanded CD8+ T cells with a cytotoxic gene expression profile in the kidneys of patients with ANCA-associated cGN. Using an experimental model of cGN, we demonstrated that clonally expanded murine CD8+ T cells highly expressed the cytotoxic molecule granzyme B. Moreover, lack of CD8+ T cells or granzyme B resulted in an ameliorated course of cGN. This was associated with reduced cleaved caspase-3 induction in renal tissue cells. Our data indicate that clonally expanded cytotoxic CD8+ T cells have a previously unrecognized pathogenic function in aggravating immune-mediated kidney disease.

immunology↗

bioRxiv2022

GM-CSF drives immune-mediated glomerular disease by licensing monocyte-derived cells to produce MMP12

Glomerulonephritis is a group of immune-mediated diseases that cause inflammation within the glomerulus and adjacent compartments of the kidney and is a major cause of end-stage renal disease. T cells are among the main drivers of glomerulonephritis. However, the T cell subsets, cytokine networks, and downstream effector mechanisms that lead to renal tissue injury are largely unknown, which has hindered the development of targeted therapies. Here we identify a population of GM-CSF-producing T cells that accumulates in the kidneys of patients with ANCA-associated glomerulonephritis, infiltrates the renal tissue in a mouse model of glomerulonephritis, and promotes tissue destruction and loss of renal function. Mechanistically, we show that GM-CSF producing T cells licence monocyte-derived cells to produce matrix metalloproteinase 12 (MMP12), which cleaves components of the glomerular basement membrane and exacerbates renal pathology. These findings provide a mechanistic rationale for the immunopathology of T cell-mediated diseases and identify the "GM-CSF - monocyte-derived cells - MMP12" pathway as a promising therapeutic target in treatment of glomerulonephritis.

immunology↗

bioRxiv2020

Deep learning-based molecular morphometrics for kidney biopsies

Morphologic examination of tissue biopsies is essential for histopathological diagnosis. However, accurate and scalable cellular quantification in human samples remains challenging. Here, we present a deep learning-based approach for antigen-specific cellular morphometrics in human kidney biopsies, which combines indirect immunofluorescence imaging with U-Net-based architectures for image-to-image translation and dual segmentation tasks, achieving human-level accuracy. In the kidney, podocyte loss represents a hallmark of glomerular injury and can be estimated in diagnostic biopsies. Thus, we profiled over 27,000 podocytes from 110 human samples, including patients with anti-neutrophil cytoplasmic antibody-associated glomerulonephritis (ANCA-GN), an immune-mediated disease with aggressive glomerular damage and irreversible loss of kidney function. Previously unknown morphometric signatures of podocyte depletion were identified in patients with ANCA-GN, which allowed patient classification and showed potential for risk stratification in combination with routine clinical tools. Together, our approach enables robust and scalable molecular morphometric analysis of human tissues, yielding deeper biological insights into the human kidney pathophysiology. SummaryDeep learning enables robust and scalable molecular morphometric analysis of human tissues, yielding deeper biological insights into the human kidney pathophysiology.

pathology↗