bioRxiv Science⌕ Search

bioRxiv · 10.1101/2025.03.17.643629

Evidence for conserved gene expression and biological processes operative in human podocytes and adult brain

Abstract

BackgroundPodocytes are essential for the proper functioning of the glomerular filtration barrier and are characterized by their intricate structure which includes well-organized primary and secondary foot processes. The brain expresses podocyte-associated proteins such as Nephrin, and Synaptopodin which are well documented. Processing of information and inter-cellular communication between podocytes and neurons employ similar molecular mechanisms which include actin-based projections, adhesion molecules, and signaling pathways. MethodsIn this study, we analysed brain-associated biological processes, transcription factors and pathways significantly regulated in UdPodocytes, i.e. podocytes differentiated from SIX2-positive UdRPCs (urine-derived renal progenitor cells). We compared gene expression in iPSC-derived brain and kidney organoids with UdPodocytes and mapped the overlapping 344 genes to brain regions via the GTEX (Genotype-Tissue Expression) database and investigated their regulation induced by the mediator of the renin-angiotensin system-angiotensin II (ANG II) ResultsThe protein interaction network of UdPodocytes genes associated with brain in GTEX contains modules for pre-synapse, post-synapse, endocrine processes and neural crest differentiation. We also found that the genes overlapping between brain and podocytes are also expressed in iPSC-derived kidney and brain organoids and could map the involved genes to all regions of the brain with the frontal cortex as the most enriched. The genes SUZ12, NFKB1 and PAX2 were the most significantly over-represented transcription factors. We independently confirmed the conserved expression of PAX6, KCNQ3, TUJ1,MAP2, TAU and ACTN4 in Udpodocytes as shown by Western blotting, Immunofluorescence and RT-PCR. We further investigated if the conserved genes are also regulated by ANGII. This unveiled genes down-regulated upon ANGII-stimulation of Udpodocytes to be associated with axon guidance, Calcium, Hippo and cGMP-PKG signaling as over-represented pathways. ConclusionIn conclusion, we have identified 344 genes with overlapping expression in brain and podocytes. These are mainly associated with synaptic signaling and cell projections. This implies that human urine-derived SIX2-renal progenitor cells differentiated into podocytes can serve as a platform for dissecting and understanding the relevance of conserved biological processes in podocytes which are currently annotated as neuron projection, axons, neurogenesis and synaptic signaling.

Source connections

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

wruck, w., Thimm, C., Adjaye, J.. 2025-03-17. Evidence for conserved gene expression and biological processes operative in human podocytes and adult brain. https://doi.org/10.1101/2025.03.17.643629

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

A G-Quadruplex Containing First Intron Harbors a Functional Polyadenylation Signal in TP53

First introns of mammalian genes are often longer than other introns and may contain regulatory elements, suggesting that they may have roles in gene regulation. We detected a previously unannotated, low abundance intronic transcript, TP53-INT1, using long-read direct RNA sequencing data. TP53-INT1 has low coding potential and terminates within the first and longest intron of TP53. The transcript structure and 3'-end were validated by independent experimental and in silico evidence. We identified a canonical polyadenylation signal upstream of the transcript termination site and demonstrated its functionality using reporter assays. Furthermore, a potential G-quadruplex (G4)-forming sequence was identified upstream of this polyadenylation signal. The G4-forming potential was confirmed using spectroscopic and thermal stability analyses. Complementing the in vitro characterizations, treatment with Pyridostatin, a G4-stabilizing drug, was associated with decreased TP53 expression. Together, these findings characterize a previously unannotated TP53 intronic transcript and reveal a local genomic context combining accessible chromatin, a functional polyadenylation signal, and a potential G4-forming sequence that may influence full-length transcription.

molecular biology↗

LOca-1: A minimal calcium-activated arginyl-specific orthocaspase from the Loki's Castle hydrothermal vent field

Orthocaspases are prokaryotic homologs of metacaspases within the C14 family of cysteine proteases, yet their biochemical properties and cellular roles remain poorly understood. Here, we report the discovery and comprehensive characterization of LOca-1, a metagenome-derived orthocaspase from the Loki's Castle hydrothermal vent field. LOca-1 consists primarily of a single, conserved p20 catalytic domain and undergoes calcium-dependent activation through cleavage at a conserved arginine residue. Once activated, LOca-1 displays strict arginyl-specific proteolytic activity and strong selectivity for residues surrounding the cleavage site. The enzyme is both thermoactive and thermostable, exhibiting maximal activity at 65 {degrees}C and a melting temperature of approximately 72 {degrees}C. Structural modelling revealed conservation of the catalytic core relative to plant metacaspases despite substantial sequence divergence. To our knowledge, LOca-1 is only the second biochemically characterized orthocaspase and the first reported from a deep-sea hydrothermal vent environment. LOca-1 expands the known biochemical diversity of prokaryotic metacaspase homologs and provides insights into the properties of a minimal p20-domain orthocaspase. Together, our findings establish LOca-1 as a thermostable, calcium-activated arginyl-specific orthocaspase and provide a foundation for future studies of orthocaspase function in prokaryotes.

molecular biology↗

A TMEM175 Mutation Disrupts the Lysosomal-Mitochondrial Axis Causing Short QT Syndrome and Sudden Cardiac Death

Short QT Syndrome (SQTS) is a rare cardiac channelopathy characterized by abnormally short QTc intervals and increased sudden cardiac death (SCD) risk. Only 20-30% of SQTS cases have been linked to genetic mutations, typi-cally in surface membrane ion channels. We identified a novel lysosomal TMEM175 gene mutation (p.Arg377His) in 7 patients in a family with SQTS and SCD. Genetic analyses, including whole exome sequencing in the family and rare-variant burden testing in [~]118,000 UK Biobank participants, sug-gested an association between TMEM175 rare variants and QT interval short-ening. Functional studies in CRISPR-engineered mice and patient-specific induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) revealed that TMEM175R377H causes shortened QT intervals and hastened repolariza-tion, respectively, as well an increased arrhythmia susceptibility. Isolated TMEM175R377H cardiomyocytes showed action potential duration (APD) abbre-viation, confirmed in whole TMEM175R377H mouse hearts and patient-specific iPSC-CM monolayers. In silico and electron microscopy studies showed that TMEM175R377H disrupts lysosomal-mitochondrial interactions, leading to mito-chondrial dysfunction, as evidenced by the reduced maximal respiration and spare respiratory capacity, with reduced ATP production, IKATP activation, and APD shortening. This mutation represents the first non-sarcolemmal ion chan-nel defect associated with SQTS and high SCD risk, potentially expanding the genetic landscape of the disease.

molecular biology↗