Biology subjects

Langner, E.

Publications and source records attributed to Langner, E..

4 recordsLinked to original sources

bioRxiv2026

Synaptopodin enables directional mechanoadaptation of integrin-based adhesions

The attachment of cells to their substrate through adhesion complexes is fundamental to tissue architecture and function. These adhesions are inherently optimized to resist shear forces parallel to the substrate, yet certain specialized cells must also withstand substantial perpendicular forces. How cells adapt their adhesion machinery to resist forces in different directions has remained unclear. In the kidney, podocytes experience perpendicular forces from pressurized filtrate flow while maintaining attachment to the glomerular basement membrane through integrin-based adhesions. Here we show that synaptopodin converts adhesions from shear-resistant to perpendicular force-resistant structures through coordinated reorganization of the actin cytoskeleton and adhesion complexes. Using an inertial force application system, we demonstrate that synaptopodin triggers force-dependent redistribution of {beta}1-integrin to the cell periphery specifically in response to perpendicular loading, while synaptopodin-deficient cells lack this directional adaptation and detach. This mechanism operates in multiple cell types and is physiologically essential: synaptopodin-null mice subjected to elevated glomerular pressure develop significant proteinuria and podocyte foot process effacement. These findings reveal a molecular basis for directional mechanoadaptation, whereby a single protein enables cells to reconfigure their adhesion architecture in response to the direction of applied force.

biophysics↗

bioRxiv2024

Ultrastructure expansion microscopy (U-ExM) of mouse and human kidneys for analysis of subcellular structures

Ultrastructure expansion microscopy (U-ExM) involves the physical magnification of specimens embedded in hydrogels, which allows for super-resolution imaging of subcellular structures using a conventional diffraction-limited microscope. Methods for expansion microscopy exist for several organisms, organs, and cell types, and used to analyze cellular organelles and substructures in nanoscale resolution. Here, we describe a simple step-by-step U-ExM protocol for the expansion, immunostaining, imaging, and analysis of cytoskeletal and organellar structures in kidney tissue. We detail the critical modified steps to optimize isotropic kidney tissue expansion, and preservation of the renal cell structures of interest. We demonstrate the utility of the approach using several markers of renal cell types, centrioles, cilia, the extracellular matrix, and other cytoskeletal elements. Finally, we show that the approach works well on mouse and human kidney samples that were preserved using different fixation and storage conditions. Overall, this protocol provides a simple and cost-effective approach to analyze both pre-clinical and clinical renal samples in high detail, using conventional lab supplies and standard widefield or confocal microscopy.

cell biology↗

bioRxiv2023

Impaired centrosome biogenesis in kidney stromal progenitors reduces abundance of interstitial lineages and accelerates injury-induced fibrosis

Defective centrosome function can disrupt embryonic kidney development, by causing changes to the renal interstitium that leads to fibrocystic disease pathologies. Yet, it remains unknown how mutations in centrosome genes impact kidney interstitial cells. Here, we examined the consequences of defective centrosome biogenesis on stromal progenitor cell growth, differentiation and fate. Conditional deletion of Cep120, a ciliopathy gene essential for centrosome duplication, in the stromal mesenchyme resulted in reduced abundance of pericytes, interstitial fibroblasts and mesangial cells. This was due to delayed mitosis, increased apoptosis, and changes in Wnt and Hedgehog signaling essential for differentiation of stromal lineages. Cep120 ablation resulted in hypoplastic kidneys with medullary atrophy and delayed nephron maturation. Finally, centrosome loss in the interstitium sensitized kidneys of adult mice, causing rapid fibrosis via enhanced TGF-{beta}/Smad3-Gli2 signaling after renal injury. Our study defines the cellular and developmental defects caused by centrosome dysfunction in embryonic kidney stroma. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=139 SRC="FIGDIR/small/535583v1_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@a3b059org.highwire.dtl.DTLVardef@8ed18corg.highwire.dtl.DTLVardef@5f573borg.highwire.dtl.DTLVardef@1581c20_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIDefective centrosome biogenesis in kidney stroma causes: C_LIO_LIReduced abundance of stromal progenitors, interstitial and mesangial cell populations C_LIO_LIDefects in cell-autonomous and paracrine signaling C_LIO_LIAbnormal/delayed nephrogenesis and tubular dilations C_LIO_LIAccelerates injury-induced fibrosis via defective TGF-{beta}/Smad3-Gli2 signaling axis C_LI

developmental biology↗

bioRxiv2022

Inhibition of Centrosome Clustering Reduces Cystogenesis and Improves Kidney Function in Autosomal Dominant Polycystic Kidney Disease

Autosomal Dominant Polycystic Kidney Disease (ADPKD) is an inherited monogenic disorder accounting for [~]5% of patients with renal failure. Yet, therapeutics for the treatment of ADPKD remain limited. ADPKD tissues display defects in the biogenesis of the centrosome which causes genome instability, aberrant ciliary signaling, and secretion of pro-inflammatory factors that drive cyst growth and fibrosis. Cystic cells form excess centrosomes via a process termed centrosome amplification (CA), which often causes abnormal multipolar spindle configurations, mitotic catastrophe, and reduced cell viability. However, cells with CA can suppress multipolarity via "centrosome clustering", a key mechanism by which cells circumvent apoptosis. Here, we demonstrate that inhibiting centrosome clustering can counteract the proliferation of renal cystic cells with high incidences of CA. Using ADPKD human cells and mouse models, we show that blocking centrosome clustering with two inhibitors, CCB02 and PJ34, blocks cyst initiation and growth in vitro and in vivo. Inhibition of centrosome clustering activates a p53-mediated mitotic surveillance mechanism leading to apoptosis, reduced cyst expansion, interstitial fibrosis, and improved kidney function. Transcriptional analysis of kidneys from treated mice identified pro-inflammatory signaling pathways implicated in CA-mediated cystogenesis and fibrosis. Our results provide the first evidence that centrosome clustering is a cyst-selective target for the improvement of renal morphology and function in ADPKD.

developmental biology↗