Biology subjects

Duran, M.

Publications and source records attributed to Duran, M..

At least 19 recordsLinked to original sources

bioRxiv2026

Functional Somatotopy of Lumbar Dorsal Rootlets and its Role in Selective Recruitment via Lateral Spinal Cord Stimulation

ObjectiveLateral spinal cord stimulation (LSCS) is a promising approach for restoring somatosensory feedback in lower-limb amputees, but its spatial selectivity remains limited. Percepts often spread to unintended regions of the residual limb, and reducing electrode contact size may not improve focality. This study investigated whether the anatomical organization of lumbar dorsal rootlets (DR) imposes fundamental constraints on LSCS selectivity. ApproachAcute neurophysiology experiments were performed in six adult cats. Both LSCS and individual DR stimulation were conducted in the same animals. For DR stimulation, bipolar hook electrodes were used to stimulate individual DR, while antidromic compound action potentials (CAPs) were recorded from femoral and sciatic nerve branches instrumented with nerve cuffs. For LSCS, custom 32-contact epidural paddle electrodes were placed over the lateral surface of the spinal cord at corresponding vertebral levels. Recruitment thresholds, dynamic ranges, and response patterns were analyzed across spinal levels, and DR recruitment patterns were directly compared to those evoked by LSCS within the same animals. Main resultsA clear rostrocaudal organization was observed across spinal levels during stimulation of individual DR, with femoral branches predominantly recruited at L4-L5 and sciatic branches at L6-L7. However, no somatotopic organization was found across DR within each spinal level; individual DR frequently co-activated multiple branches within the same group, and selective recruitment could only be maintained over a narrow dynamic range (median [~]10 {micro}A). LSCS exhibited even a narrower dynamic range ([~]5 {micro}A) but closely mirrored DR recruitment patterns, indicating that LSCS activates sensory afferents in a manner determined by the organizational structure of the DR. SignificanceThese findings demonstrate that the limited spatial selectivity of LSCS can largely be attributed to the coarse organization of DR within each root level rather than due to limitations of epidural electrode design. Moving electrodes intradurally or reducing contact size further is unlikely to substantially improve focality. Instead, improving paddle stability to ensure consistent placement over the appropriate spinal levels may be a more effective strategy for enhancing percept localization.

neuroscience↗

bioRxiv2026

A comparison of BirdNET, expert listening and acoustic indices to monitor avian diversity in a Mediterranean agricultural landscape

Passive acoustic monitoring poses an immense potential to assess avian diversity in many habitats, including agricultural landscapes. At the same time, automated recorders generate large datasets which present a challenge for processing and effectively assessing biodiversity. Methods such as manual listening by experts, automated detection algorithms like BirdNET and calculating acoustic indices all present different trade-offs in assessment of biodiversity through passive acoustic monitoring. In the present study we recorded soundscapes in a low-intensity agricultural landscape in western Turkiye in all four seasons. Two expert ornithologists listened to a subset of these recordings identifying bird species from the recordings. We also ran the same sample of recordings on BirdNET to compare BirdNET detections with expert detections and calculated acoustic indices for each recording. The results showed that BirdNET detected more species than experts, although some may not be reliable detections. Two acoustic indices (bioacoustic index and acoustic complexity index) were correlated positively with number of species detected by experts and one (normalized difference soundscape index) with number of species detected by BirdNET but the correlations were modest. The results show that acoustic indices may have limited value in detecting biodiversity and automated detection algorithms may do a better job, although these may need to be trained with local data to improve detection and classification.

ecology↗

bioRxiv2026

The central amygdala integrates exogenous glucagon-like peptide 1 signals

Nuclei within the limbic system like the central amygdala (CeA) play a critical role in mediating fear, motivation, reward, and appetitive behavior. Although previous reports demonstrate the presence of the glucagon-like peptide-1 receptor (GLP-1R) in limbic nuclei, how limbic neurons mediate the actions of systemically administrated GLP-1R agonists is unclear. In this study, we investigated the CeAs response to peripherally administered GLP-1R agonist Exendin-4 (Ex-4) in vivo, and determined the functional requirement of select CeA neuron populations in acute Ex-4 induced hypophagia. Using fiber photometry, we observed that Ex-4 promoted a rapid and lasting activation of CeA neurons that was blocked by pretreatment with the GLP-1R antagonist Exendin-9. We then tested the functional requirement of CeA neuron activation in mediating Ex-4 induced hypophagia of standard grain chow using inhibitory chemogenetics. Chemogenetic inhibition of all CeA neurons significantly suppressed the hypophagic actions of Ex-4. Then using selective mouse Cre-drivers, we found that chemogenetic inhibition of protein kinase c delta (Prk-cd CeA) and GLP-1R (Glp1r CeA), but not somatostatin (SstCeA), neurons also attenuates the full hypophagic effect of Ex-4. Having observed that inhibition of Glp1rCeA modestly attenuated Ex-4 induced hypophagia of standard chow, we then tested whether these neurons might mediate Ex-4 suppression of energy-dense, palatable diet. We used intermittent high-fat diet (HFD) access and found that inhibition of Glp1rCeA neurons significantly rescued the reduction of HFD consumption by Ex-4. Collectively, these data demonstrate that the CeA responds to peripherally administered GLP-1R agonists and that multiple CeA neuron mediate GLP-1R agonist-mediated hypophagia.

neuroscience↗

bioRxiv2025

TMEM9 and SEC22B interact with ClC-5 to shape renal proximal tubule function and Dent's Disease type I pathogenesis

Cl-/H+ antiporter ClC-5 is a key regulator of renal proximal tubule function, primarily by controlling endosomal acidification. Loss-of-function mutations in ClC-5 cause Dents Disease type 1 (DD1), a rare renal tubulopathy that progresses to kidney failure with varying severity. To understand the specific mechanisms linking ClC-5 loss-of-function with DD1 phenotypic heterogeneity, three ClC-5 pathogenic mutations (I524K, E527D and V523{Delta}) were investigated using renal proximal tubule epithelial cell lines. We have identified distinct intracellular retention patterns of these ClC-5 mutants, all leading to altered endolysosomal pH and disrupted secretory pathway organization. Through an interactome analysis, we have uncovered several ClC-5 partners including TMEM9, which interacted with all ClC-5 forms. TMEM9 knockdown (KD) recapitulated key DD1 characteristics, like defective endocytosis and epithelial dedifferentiation, but paradoxically enhanced endosomal acidification. The secretory pathway was also altered in cells lacking TMEM9 (e.g. enlarged endosomes, and fragmented Golgi apparatus). A similar phenotype was observed in cells depleted of SEC22B; an R-SNARE that we have found to specifically interact with wild-type ClC-5, but not the mutants. Notably, its deletion impaired ClC-5 trafficking, causing its retention at the Golgi and endosomes. Altogether, our findings highlight the relevance of TMEM9 and SEC22B in ClC-5 function, suggesting them as DD1 pathophysiology modifiers.

cell biology↗

bioRxiv2025

Single-cell, multi-region profiling of the macaque brain across the lifespan

Brain aging is a complex process with profound health and societal consequences. However, the molecular and cellular pathways that govern its temporal progression-along with any cell type-, region-, and sex-specific heterogeneity in such progression-remain poorly defined. Here, we present a transcriptomic atlas of 5.3 million cells from 582 samples spanning 11 brain regions of 55 rhesus macaques (29 female, 26 male), aged 5 months (early life) to 21 years (late adulthood). We annotate 12 major cell classes and 225 subclusters, including region-specific subtypes of excitatory and inhibitory neurons, astrocytes, and ependymal cells. We identify a vulnerable excitatory neuron population in the superficial cortical lamina and a cortical interneuron population that are less abundant later in life, along with subtle, region-specific, age-associated compositional differences in subpopulations of microglia and oligodendrocytes, whose detection required single-cell resolution. Finally, we chart convergent and divergent age-associated molecular signatures across brain regions and cell classes-where some of these signatures are sex-specific and could underlie sex biases in neurological disorders. We find that age-associated transcriptional programs not only overlap substantially with those seen in Alzheimers disease (AD), but also unfold along distinct temporal trajectories across brain regions, suggesting that aging and AD may share molecular roots that emerge at different life stages and in region-specific, sex-specific windows of vulnerability. This work provides a temporal, regional, and sex-stratified atlas of the aging primate brain, offering insights into cell type-specific vulnerabilities and regional heterogeneity with translational human relevance.

neuroscience↗

bioRxiv2025

Bile Salts and Bacterial Bile Salt Hydrolase Activity Differentially Influence Escherichia coli Colonization and FXR Signaling in Colorectal Cancer Organoids

Bile salts are key regulators of host-microbe interactions and epithelial signaling in the intestine. Gut bacteria can deconjugate primary bile salts, which can be leveraged to engineer targeted therapies through bile salt hydrolase (BSH) activity. However, the interplay between bile salt signaling, microbial metabolism, and tumor-associated colonization remains poorly understood. Here, we establish an in vitro colon organoid platform to dissect bile salt-driven epithelial-microbe dynamics at cellular resolution. Using this system, we found that bile salts markedly modulated colonization of native Escherichia coli (EcAZ-2) and a BSH-expressing strain (EcAZ-2LsBSH) in healthy versus tumor murine organoids. Under bile salt exposure, EcAZ-2LsBSH preferentially colonized tumor organoids, though overall colonization was lower than that of the non-BSH strain. Beyond effects on bacterial colonization, bile salts also directly activated host signaling pathways. In presence of bile salts, EcAZ-2LsBSH significantly enhanced activation of bile acid receptors such as farnesoid X receptor (FXR) by 2-fold in healthy organoids. These findings reveal a mechanistic bridge between in vivo microbial function and bile salt interactions, offering potential microbiota and bile acid targeted therapeutic strategies.

cancer biology↗

bioRxiv2025

Exploring genomic diversity and reproductive strategies in three expansion phases of the superdominant Brachypodium rupestre in high mountain grasslands

Tall-grass expansion in natural plant communities is a concern under current global change scenarios. Driven by factors such as community vulnerability and the competitive abilities of tall-grass species, this phenomenon is exemplified by Brachypodium rupestre (Host) Roem. & Schult, a perennial tall-grass native to Europe. B. rupestre spreads aggressively in the grasslands of the western Pyrenees due to a disrupted regime of lack of herbivory and recurrent burnings that has persisted over several decades. This study aims to investigate whether the contrasted managements of grazing, abandonment and burnings have promoted specific reproductive traits and impacted the population genomics of B. rupestre. Nine sites varying in cover of B. rupestre classified into three expansion phases associated to different management regimes were monitored: i) scattered populations in multispecific grazed sites, ii) stand populations expanding at sites of relaxed grazing or abandonment, and iii) superdominant populations constituting dense degraded covers in recurrently burned sites. ddRADseq data showed high genomic diversity but relatively low genomic structure, likely due to substantial gene flow and the absence of wind barriers. The standardized index of association supported asexual reproduction in all populations, which is coupled with sexual reproduction. Contrasting management practices did not promote distinct genomic identities between expansion phases; rather, the genetic differentiation and divergence of populations responded to life history and spatial isolation, even within a small geographic area. The similar levels of genetic diversity and the significantly different number of clones between expansion phases suggest a complex pattern of genotypic and clonal variability, which may be influenced by environmental factors (historical disturbance regimes).

plant biology↗

bioRxiv2025

Barcoded monoclonal embryoids are a potential solution to confounding bottlenecks in mosaic organoid screens

Genetic screens in organoids hold tremendous promise for accelerating discoveries at the intersection of genomics and developmental biology. Embryoid bodies (EBs) are self-organizing multicellular structures that recapitulate aspects of early mammalian embryogenesis. We set out to perform a CRISPR screen perturbing all transcription factors (TFs) in murine EBs. Specifically, a library of TF-targeting guide RNAs (gRNAs) was used to generate mouse embryonic stem cells (mESCs) bearing single TF knockouts. Aggregates of these mESCs were induced to form mouse EBs, such that each resulting EB was mosaic with respect to the TF perturbations represented among its constituent cells. Upon performing single cell RNA-seq (scRNA-seq) on cells derived from mosaic EBs, we found many TF perturbations exhibiting large and seemingly significant effects on the likelihood that individual cells would adopt certain fates, suggesting roles for these TFs in lineage specification. However, to our surprise, these results were not reproducible across biological replicates. Upon further investigation, we discovered cellular bottlenecks during EB differentiation that dramatically reduce clonal complexity, curtailing statistical power and confounding interpretation of mosaic screens. Towards addressing this challenge, we developed a scalable protocol in which each individual EB is monoclonally derived from a single mESC and genetically barcoded. In a proof-of-concept experiment, we show how these monoclonal EBs enable us to better quantify the consequences of TF perturbations as well as inter-individual heterogeneity across EBs harboring the same genetic perturbation. Looking forward, monoclonal EBs and EB-derived organoids may be powerful tools not only for genetic screens, but also for modeling Mendelian disorders, as their underlying genetic lesions are overwhelmingly constitutional (i.e. present in all somatic cells), yet give rise to phenotypes with incomplete penetrance and variable expressivity.

developmental biology↗

bioRxiv2025

A statistical framework for inferring genetic requirements from embryo-scale single-cell sequencing experiments

Improvements in single-cell sequencing have enabled phenotyping at organism-scale and molecular resolution, but interpreting such experiments poses computational challenges. Identifying the genes and cell types directly impacted by genetic, chemical, or environmental perturbations requires explicit modeling of lineage relationships amongst many cell types, over time, from datasets with millions of cells collected from thousands of specimens. We describe two software tools, "Hooke" and "Platt", which exploit the rich statistical patterns within single-cell datasets to characterize the direct molecular and cellular consequences of experimental perturbations. We apply Hooke and Platt to a single-cell atlas of thousands of perturbed zebrafish embryos to synthesize a coherent map of lineage dependencies and leverage it to reveal previously unappreciated roles for fate-determining transcription factors. We show that cell type covariation in single-cell datasets is a powerful source of information for inferring how cells depend on genes and one another in the program of vertebrate development.

bioinformatics↗

bioRxiv2025

Embryo-scale single-cell chemical transcriptomics reveals dependencies between cell types and signaling pathways

Organogenesis is a highly organized process that is conserved across vertebrates and is heavily dependent on intercellular signaling to achieve cell type identity. We lack a comprehensive understanding of how developing cell types in each organ and tissue depend on developmental signaling pathways. To address this gap in knowledge, we captured the molecular consequences of inhibiting each of the seven major developmental signaling pathways in zebrafish, using large-scale whole embryo single cell RNA-seq from over two million cells. This approach allowed us to detect signaling pathway regulation even in very rare cell types. By focusing on the development of the pectoral fin, we uncovered two new cell types (distal mesenchyme and tenocytes) and multiple novel signaling dependencies during pectoral fin development. This resource serves as a valuable tool for investigators seeking to rapidly assess the role of the major signaling pathways during the formation of their tissue of interest.

developmental biology↗

bioRxiv2024

Named Entity Recognition of Pharmacokinetic parameters in the scientific literature

The development of accurate predictions for a new drugs absorption, distribution, metabolism, and excretion profiles in the early stages of drug development is crucial due to high candidate failure rates. The absence of comprehensive, standardised, and updated pharmacokinetic (PK) repositories limits pre-clinical predictions and often requires searching through the scientific literature for PK parameter estimates from similar compounds. While text mining offers promising advancements in automatic PK parameter extraction, accurate Named Entity Recognition (NER) of PK terms remains a bottleneck due to limited resources. This work addresses this gap by introducing novel corpora and language models specifically designed for effective NER of PK parameters. Leveraging active learning approaches, we developed an annotated corpus containing over 4,000 entity mentions found across the PK literature on PubMed. To identify the most effective model for PK NER, we fine-tuned and evaluated different NER architectures on our corpus. Fine-tuning BioBERT exhibited the best results, achieving a strict F1 score of 90.37% in recognising PK parameter mentions, significantly outperforming heuristic approaches and models trained on existing corpora. To accelerate the development of end-to-end PK information extraction pipelines and improve pre-clinical PK predictions, the PK NER models and the labelled corpus were released open source at https://github.com/PKPDAI/PKNER.

pharmacology and toxicology↗

bioRxiv2023

KMT2A oncoproteins induce epigenetic resistance to targeted therapies

Chromosomal translocations involving the Lysine-Methyl-Transferase-2A (KMT2A) locus generate potent oncogenic fusion proteins (oncoproteins) that disrupt regulation of developmental gene expression. By profiling the oncoprotein-target sites of 36 broadly representative KMT2A-rearranged leukemia samples, including three samples that underwent a lymphoid-to-myeloid lineage-switching event in response to therapy, we find the genomic enrichment of the oncoprotein is highly variable between samples and subject to dynamic regulation. At high levels of expression, the oncoproteins preferentially activate either an acute lymphoblastic leukemia (ALL) program, enriched for pro-B-cell genes, or an acute myeloid leukemia (AML) program, enriched for hematopoietic-stem-cell genes. The fusion-partner-specific-binding patterns over these gene sets are highly correlated with the prevalence of each mutation in ALL versus AML. In lineage-switching samples the oncoprotein levels are reduced and the oncoproteins preferentially activate granulocyte-monocyte progenitor (GMP) genes. In a sample that lineage switched during treatment with the menin inhibitor revumenib, the oncoprotein and menin are reduced to undetectable levels, but ENL, a transcriptional cofactor of the oncoprotein, persists on numerous oncoprotein-target loci, including genes in the GMP-like lineage-switching program. We propose KMT2A oncoproteins promote lineage-switching events through dynamic chromatin binding and can induce epigenetic lesions, marked by ENL, that support resistance to targeted therapies.

cancer biology↗

bioRxiv2023

Activity of brain stem glucagon neurons are modulated by energy state and encode sex and frequency-dependent negative valence and anxiety.

The glucagon-like peptide 1 (GLP-1) system has emerged as an important drug target for the treatment of obesity and diabetes. Preclinical and clinical studies demonstrate that the activation of GLP-1 receptors (GLP-1Rs) directly in the brain through overexpression of GLP-1 or GLP-1R agonists produces potent anorexigenic effects, yet the behavioral role and modulation of the endogenous GLP-1 producing system in the brain by energy status is unclear. In this study, we examined the anatomical, physiological, and behavioral properties of preproglucagon-expressing neurons in the nucleus of the solitary tract, GcgNTS neurons, which serve as the primary source of GLP-1 in the brain. Using transgenic laboratory mice, we observed no sex differences in the density and distribution of GcgNTS neurons in male and female mice. Fos immunolabeling experiments show that GcgNTS neurons are not significantly activated after intermittent access to palatable food, but the magnitude of Fos activation was linearly related to the amount of food intake in mice provided with ad libitum intermittent access to palatable food. Electrophysiological examination of GcgNTS neurons revealed that these neurons show energy-status and sex-dependent changes in neuronal firing and intrinsic excitability. Twenty-four hour food deprivation produced a significant reduction in excitability and firing in male, but not female mice. We then used optogenetics to investigate the causal behavioral role of GcgNTS neurons. High frequency optogenetic activation of GcgNTS neurons using the red light-gated opsin ChrimsonR produced female-specific anxiety-like behavior and real-time place aversion. For feeding, we observed that reversible optogenetic stimulation at high frequencies produced a significant reduction in homeostatic refeeding that did not differ by sex. Using operant conditioning, we found that reversible optogenetic activation of GcgNTS neurons at 20 Hz, but not 5, also reduces appetitive behavior. These data demonstrate that GcgNTS neurons exert control over motivation and food-seeking behavior in addition to consumption.

neuroscience↗

bioRxiv2023

Renal Cl-/H+ antiporter ClC-5 regulates collagen production and release in Dent Disease models

Mutations in the Cl-/H+ antiporter ClC-5 cause Dents Disease 1 (DD1), a rare primary tubulopathy that eventually progresses to renal failure. In fact, even with normal kidney function, DD1 patients present renal tubulointerstitial fibrosis. However, the link between ClC-5 loss-of-function and renal fibrosis remains unclear. Here, we have shown that DD1 mice models lacking ClC-5 present higher renal collagen deposition and fibrosis. Accordingly, deletion of ClC-5 in human renal proximal tubule epithelial cells (CLCN5 KD) recapitulates this effect. We have demonstrated that CLCN5 KD causes an increase of collagen I (Col I) and IV (Col IV) intracellular levels by promoting their transcription through {beta}-catenin pathway and impairing their lysosomal-mediated degradation. In addition, CLCN5 KD cells release more Col I and IV at the extracellular space that form fibres with altered properties and resistance to removal compared to control cells. Altogether, we describe a new regulatory mechanism for collagens production and release by ClC-5, which is altered in DD1 and provides a better understanding of disease progression to renal fibrosis. SIGNIFICANCE STATEMENTRenal fibrosis is a common pathologic process occurring as consequence of chronic kidney injury and leading to renal dysfunction. Dents Disease is a rare renal pathology that progresses to chronic kidney disease and tubulointerstitial fibrosis. Interestingly, it is caused by mutations in a single gene called CLCN5, therefore it can help understanding the cellular mechanisms of renal fibrosis. Using cellular and mice models of the disease, we describe a mechanism linking CLCN5 function, cell differentiation and regulation of collagen levels, major component of extracellular matrix and important player for renal fibrosis development. In conclusion, our results provide a link between CLCN5 and altered collagen deposition, which could be relevant for other renal Fanconi syndrome related diseases also progressing to fibrosis.

cell biology↗

bioRxiv2022

Proteostasis governs differential temperature sensitivity across embryonic cell types

The genetic program of embryonic development is remarkably robust, but temperature stress can degrade its ability to generate animals with invariant anatomy. While the stereotyped, consistent phenotypes associated with environmental stress during vertebrate development suggest that some cell types are more sensitive to stress than others, the basis of this sensitivity is unknown. Here, we characterize hundreds of individual zebrafish embryos under temperature stress using whole-animal single cell RNA-seq to identify cell types and molecular programs within them that drive phenotypic variability. We find that temperature perturbs the normal proportions and gene expression programs of numerous cell types and also introduces asynchrony in their development. The notochord is particularly sensitive to temperature stress, which we show is due to a specialized cell type, sheath cells. Further analyses show that sheath cells accumulate misfolded protein at elevated temperature, leading to a cascading structural failure of the notochord and irreversible anatomic defects in the embryo. Our study demonstrates that whole-animal single cell RNA-seq can characterize mechanisms important for developmental robustness and pinpoint molecular programs within specific cell types that constitute key failure points.

genomics↗

bioRxiv2022

Deep molecular, cellular and temporal phenotyping of developmental perturbations at whole organism scale

The maturation of single cell transcriptomic technologies has facilitated the generation of comprehensive cellular atlases from whole embryos. A majority of this data, however, has been collected from wild type embryos without an appreciation for latent variation present in development. Here we present single cell transcriptomic data from 1812 individually resolved developing zebrafish embryos, encompassing 19 time points, 23 genetic perturbations, and totaling 3.2M cells. The high degree of replication in our study (8 or more embryos per condition) allows us to estimate the variance in cell type abundance organism-wide and to detect perturbation-dependent deviance in cell type composition relative to wild type embryos. Our approach is sensitive to rare cell types, resolving developmental trajectories and genetic dependencies in the cranial ganglia neurons, a cell population that comprises less than 1% of the embryo. Additionally, time-series profiling of individual mutants identified a group of brachyury-independent cells with strikingly similar transcriptomes to notochord sheath cells, leading to new hypotheses about the origins of the skull. We anticipate that standardized collection of high-resolution, organism-scale single cell data from large numbers of individual embryos will enable mapping the genetic dependencies of zebrafish cell types, while also addressing long-standing challenges in developmental genetics, including the cellular and transcriptional plasticity underlying phenotypic diversity across individuals.

genomics↗

bioRxiv2022

Epigenetic dysregulation from chromosomal transit in micronuclei

Chromosomal instability (CIN) and epigenetic alterations are characteristics of advanced and metastatic cancers [1-4], yet whether they are mechanistically linked is unknown. Here we show that missegregation of mitotic chromosomes, their sequestration in micronuclei [5, 6], and subsequent micronuclear envelope rupture [7] profoundly disrupt normal histone post-translational modifications (PTMs), a phenomenon conserved across humans and mice as well as cancer and non-transformed cells. Some of the changes to histone PTMs occur due to micronuclear envelope rupture whereas others are inherited from mitotic abnormalities prior to micronucleus formation. Using orthogonal techniques, we show that micronuclei exhibit extensive differences in chromatin accessibility with a strong positional bias between promoters and distal or intergenic regions. Finally, we show that inducing CIN engenders widespread epigenetic dysregulation and that chromosomes which transit in micronuclei experience durable abnormalities in their accessibility long after they have been reincorporated into the primary nucleus. Thus, in addition to genomic copy number alterations, CIN can serve as a vehicle for epigenetic reprogramming and heterogeneity in cancer.

cancer biology↗

bioRxiv2020

Global gene-expression analysis reveals the molecular processes underlying ClC-5 loss-of-function in novel Dent Disease 1 cellular models

Dent disease 1 (DD1) is a rare X-linked renal proximal tubulopathy characterized by low molecular weight proteinuria (LMWP) and variable degree of hypercalciuria, nephrocalcinosis and/or nephrolithiasis with progression to chronic kidney disease (CKD). Although loss-of-function mutations in the gene CLCN5 encoding the electrogenic Cl-/H+ antiporter ClC-5, which impair endocytic uptake in proximal tubule cells, cause the disease, there is poor genotype-phenotype correlation and their contribution to proximal tubule dysfunction remains unclear. Here, in order to discover the mechanisms leading to proximal tubule dysfunction due to ClC-5 loss-of-function, we have generated and characterized new human cellular models of DD1 by silencing CLCN5 and introducing the ClC-5 pathogenic mutants V523del, E527D and I524K into the human proximal tubule-derived cell line RPTEC/TERT1. Depletion of CLCN5 or expression of mutant ClC-5 impairs albumin endocytosis, increases substrate adhesion and decreases collective migration, which correlates with a less differentiated epithelial phenotype. Interestingly, although all conditions compromised the endocytic capacity in a similar way, their impact on gene expression profiles was different. Our DNA microarray studies show that ClC-5 silencing or mutant re-introduction alter pathways related to nephron development, anion homeostasis, organic acid transport, extracellular matrix organization and cell migration, compared to control cells. Cells carrying the V523del ClC-5 mutation show the largest differences in gene expression vs WT cells, which is in agreement with the more aggressive clinical phenotype observed in some DD1 patients. Overall, this work emphasizes the use of human proximal tubule derived cell models to identify the molecular processes underlying ClC-5 deficiency.

pathology↗