Kidney Disease Gene Research Articles

Molecular characterization of PANoptosis-related genes in chronic kidney disease.

Chronic kidney disease (CKD) is characterized by fibrosis and inflammation in renal tissues. Several types of cell death have been implicated in CKD onset and progression. Unlike traditional forms of cell death, PANoptosis is characterized by the crosstalk among programmed cell death pathways. However, the interaction between PANoptosis and CKD remains unclear. Here, we used bioinformatics methods to identify differentially expressed genes and differentially expressed PANoptosis-related genes (DE-PRGs) using data from the GSE37171 dataset. Following this, we further performed gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, and gene set enrichment analysis using the data. We adopted a combined approach to select hub genes, using the STRING database and CytoHubba plug-in, and we used the GSE66494 as a validation dataset. In addition, we constructed ceRNA, transcription factor (TF)-gene, and drug-gene networks using Cytoscape. Lastly, we conducted immunohistochemical analysis and western blotting to validate the hub genes. We identified 57 PANoptosis-associated genes as DE-PRGs. We screened nine hub genes from the 57 DE-PRGs. We identified two hub genes (FOS and PTGS2) using the GSE66494 database, Nephroseq, immunohistochemistry, and western blotting. A common miRNA (Hsa-miR-101-3p) and three TFs (CREB1, E2F1, and RELA) may play a crucial role in the onset and progression of PANoptosis-related CKD. In our analysis of the drug-gene network, we identified eight drugs targeting FOS and 52 drugs targeting PTGS2.

Multi-scalar data integration decoding risk genes for chronic kidney disease

BackgroundChronic Kidney Disease (CKD) impacts over 10% of the global population, and recent advancements in high-throughput analytical technologies are uncovering the complex physiology underlying this condition. By integrating Genome-Wide Association Studies (GWAS), RNA sequencing (RNA-seq/RNA array), and single-cell RNA sequencing (scRNA-seq) data, our study aimed to explore the genes and cell types relevant to CKD traits.MethodsGWAS summary data for end-stage renal failure (ESRD) and decreased eGFR (CKD) with or without diabetes and (micro)proteinuria were obtained from the GWAS Catalog and the UK Biobank (UKB) database. Two gene Expression Omnibus (GEO) transcriptome datasets were used to establish glomerular and tubular gene expression differences between CKD patients and healthy individuals. Two scRNA-seq datasets were utilized to obtain the expression of key genes at the single-cell level. The expression profile, differentially expressed genes (DEGs), gene-gene interaction, and pathway enrichment were analysed for these CKD risk genes.ResultsA total of 779 distinct SNPs were identified from GWAS across different CKD traits, involving 681 genes. While many of these risk genes are specific to the CKD traits of renal failure, decreased eGFR, and (micro)proteinuria, they share common pathways, including extracellular matrix (ECM). ECM modeling was enriched in upregulated glomerular and tubular DEGs from CKD kidneys compared to healthy controls, with the expression of relevant collagen genes, such as COL1A2, prevalent in fibroblasts/myofibroblasts. Additionally, immune responses, including T cell differentiation, were dysregulated in CKD kidneys. The late podocyte signature gene THSD7A was enriched in podocytes but downregulated in CKD. We also highlighted that the regulated risk genes of CKD are mainly expressed in tubular cells and immune cells in the kidney.ConclusionsOur integrated analysis highlight the genes, pathways, and relevant cell types associational with the pathogenesis of kidney traits, as a basis for further mechanistic studies to understand the pathogenesis of CKD.

Sex-specific molecular signature of mouse podocytes in homeostasis and in response to pharmacological challenge with rapamycin

BackgroundSex differences exist in the prevalence and progression of major glomerular diseases. Podocytes are the essential cell-type in the kidney which maintain the physiological blood-urine barrier, and pathological changes in podocyte homeostasis are critical accelerators of impairment of kidney function. However, sex-specific molecular signatures of podocytes under physiological and stress conditions remain unknown. This work aimed at identifying sexual dimorphic molecular signatures of podocytes under physiological condition and pharmacologically challenged homeostasis with mechanistic target of rapamycin (mTOR) inhibition. mTOR is a crucial regulator involved in a variety of physiological and pathological stress responses in the kidney and inhibition of this pathway may therefore serve as a general stress challenger to get fundamental insights into sex differences in podocytes.MethodsThe genomic ROSAmT/mG-NPHS2 Cre mouse model was used which allows obtaining highly pure podocyte fractions for cell-specific molecular analyses, and vehicle or pharmacologic treatment with the mTOR inhibitor rapamycin was performed for 3 weeks. Subsequently, deep RNA sequencing and proteomics were performed of the isolated podocytes to identify intrinsic sex differences. Studies were supplemented with metabolomics from kidney cortex tissues.ResultsAlthough kidney function and morphology remained normal in all experimental groups, RNA sequencing, proteomics and metabolomics revealed strong intrinsic sex differences in the expression levels of mitochondrial, translation and structural transcripts, protein abundances and regulation of metabolic pathways. Interestingly, rapamycin abolished prominent sex-specific clustering of podocyte gene expression and induced major changes only in male transcriptome. Several sex-biased transcription factors could be identified as possible upstream regulators of these sexually dimorphic responses. Concordant to transcriptomics, metabolomic changes were more prominent in males. Remarkably, high number of previously reported kidney disease genes showed intrinsic sexual dimorphism and/or different response patterns towards mTOR inhibition.ConclusionsOur results highlight remarkable intrinsic sex-differences and sex-specific response patterns towards pharmacological challenged podocyte homeostasis which might fundamentally contribute to sex differences in kidney disease susceptibilities and progression. This work provides rationale and an in-depth database for novel targets to be tested in specific kidney disease models to advance with sex-specific treatment strategies.

Whole-exome and whole-genome sequencing of 1064 individuals with type 1 diabetes reveals novel genes for diabetic kidney disease

Aims/hypothesisDiabetic kidney disease (DKD) is a severe diabetic complication that affects one third of individuals with type 1 diabetes. Although several genes and common variants have been shown to be associated with DKD, much of the predicted inheritance remains unexplained. Here, we performed next-generation sequencing to assess whether low-frequency variants, extending to a minor allele frequency (MAF) ≤10% (single or aggregated) contribute to the missing heritability in DKD.MethodsWe performed whole-exome sequencing (WES) of 498 individuals and whole-genome sequencing (WGS) of 599 individuals with type 1 diabetes. After quality control, next-generation sequencing data were available for a total of 1064 individuals, of whom 541 had developed either severe albuminuria or end-stage kidney disease, and 523 had retained normal albumin excretion despite a long duration of type 1 diabetes. Single-variant and gene-aggregate tests for protein-altering variants (PAV) and protein-truncating variants (PTV) were performed separately for WES and WGS data and combined in a meta-analysis. We also performed genome-wide aggregate analyses on genomic windows (sliding window), promoters and enhancers using the WGS dataset.ResultsIn the single-variant meta-analysis, no variant reached genome-wide significance, but a suggestively associated common THAP7 rs369250 variant (p=1.50 × 10−5, MAF=49%) was replicated in the FinnGen general population genome-wide association study (GWAS) data for chronic kidney disease and DKD phenotypes. The gene-aggregate meta-analysis provided suggestive evidence (p<4.0 × 10−4) at four genes for DKD, of which NAT16 (MAFPAV≤10%) and LTA (also known as TNFβ, MAFPAV≤5%) are replicated in the FinnGen general population GWAS data. The LTA rs2229092 C allele was associated with significantly lower TNFR1, TNFR2 and TNFR3 serum levels in a subset of FinnDiane participants. Of the intergenic regions suggestively associated with DKD, the enhancer on chromosome 18q12.3 (p=3.94 × 10−5, MAFvariants≤5%) showed interaction with the METTL4 gene; the lead variant was replicated, and predicted to alter binding of the MafB transcription factor.Conclusions/interpretationOur sequencing-based meta-analysis revealed multiple genes, variants and regulatory regions that were suggestively associated with DKD. However, as no variant or gene reached genome-wide significance, further studies are needed to validate the findings.Graphical

Evaluating the Effect of Estimating Renal Function With the CKD-EPI 2021 Equation on the ABCD-GENE Score for Clopidogrel Response Prediction.

The ABCD-GENE score was developed to predict poor response to clopidogrel and includes Age, Body mass index, Chronic kidney disease (CKD; estimated glomerular filtration rate [eGFR] < 60 mL/min/1.73 m2), Diabetes, and CYP2C19 GENE variants; a score ≥ 10 is predictive of reduced clopidogrel effectiveness after percutaneous coronary intervention (PCI). Estimation of GFR without a race variable via the CKD-EPI Scr 2021 equation is now recommended. We examined the impact of using the CKD-EPI Scr 2021 vs. 2009 equation on the ABCD-GENE score for post-PCI patients. A total of 4335 adult patients (n = 925 Black) who underwent PCI and CYP2C19 genotyping were included, with GFR estimated for each patient via the CKD-EPI Scr 2021 and CKD-EPI 2009 equations. The ABCD-GENE score, calculated based on each GFR estimation, was compared. With the CKD-EPI Scr 2021 vs. 2009 equation, median (IQR) eGFR was lower (74 [55-94] vs. 81 [60-103] mL/min/1.73 m2, P < 0.001), and CKD prevalence was higher (31% vs. 25%, P < 0.001) among Black patients, whereas eGFR was higher (85 [65-99] vs. 80 [61-94] mL/min/1.73m2, P < 0.001), and CKD prevalence was lower (20% vs. 24%, P < 0.001) in non-Black patients. This led to 12 (1%) Black patients being reclassified from low to high risk of poor clopidogrel response and 30 (1%) non-Black patients being recategorized from high to low risk (P < 0.001 for both comparisons). Removal of the race variable from GFR estimation significantly impacted the prediction of clopidogrel effectiveness via the ABCD-GENE score.

Targeted RNAseq from patients’ urinary cells to validate pathogenic noncoding variants in autosomal dominant polycystic kidney disease genes: a proof of concept

Targeted RNAseq from patients’ urinary cells to validate pathogenic noncoding variants in autosomal dominant polycystic kidney disease genes: a proof of concept

Exploring Potential Novel Causal Genes for Chronic Kidney Disease

Exploring Potential Novel Causal Genes for Chronic Kidney Disease

ACSS2 gene variants determine kidney disease risk by controlling de novo lipogenesis in kidney tubules.

Worldwide, over 800 million people are affected by kidney disease, yet its pathogenesis remains elusive, hindering the development of novel therapeutics. In this study, we used kidney-specific expression of quantitative traits and single-nucleus open chromatin analysis to show that genetic variants linked to kidney dysfunction on chromosome 20 target the acyl-CoA synthetase short-chain family 2 (ACSS2). By generating ACSS2-KO mice, we demonstrated their protection from kidney fibrosis in multiple disease models. Our analysis of primary tubular cells revealed that ACSS2 regulated de novo lipogenesis (DNL), causing NADPH depletion and increasing ROS levels, ultimately leading to NLRP3-dependent pyroptosis. Additionally, we discovered that pharmacological inhibition or genetic ablation of fatty acid synthase safeguarded kidney cells against profibrotic gene expression and prevented kidney disease in mice. Lipid accumulation and the expression of genes related to DNL were elevated in the kidneys of patients with fibrosis. Our findings pinpoint ACSS2 as a critical kidney disease gene and reveal the role of DNL in kidney disease.

SCARF Genes in COVID-19 and Kidney Disease: A Path to Comorbidity-Specific Therapies.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19), which has killed ~7 million persons worldwide. Chronic kidney disease (CKD) is the most common risk factor for severe COVID-19 and one that most increases the risk of COVID-19-related death. Moreover, CKD increases the risk of acute kidney injury (AKI), and COVID-19 patients with AKI are at an increased risk of death. However, the molecular basis underlying this risk has not been well characterized. CKD patients are at increased risk of death from multiple infections, to which immune deficiency in non-specific host defenses may contribute. However, COVID-19-associated AKI has specific molecular features and CKD modulates the local (kidney) and systemic (lung, aorta) expression of host genes encoding coronavirus-associated receptors and factors (SCARFs), which SARS-CoV-2 hijacks to enter cells and replicate. We review the interaction between kidney disease and COVID-19, including the over 200 host genes that may influence the severity of COVID-19, and provide evidence suggesting that kidney disease may modulate the expression of SCARF genes and other key host genes involved in an effective adaptive defense against coronaviruses. Given the poor response of certain CKD populations (e.g., kidney transplant recipients) to SARS-CoV-2 vaccines and their suboptimal outcomes when infected, we propose a research agenda focusing on CKD to develop the concept of comorbidity-specific targeted therapeutic approaches to SARS-CoV-2 infection or to future coronavirus infections.

Identification and Validation of Neutrophil Extracellular Traps-Associated Genes in Diabetic Kidney Disease: Integration Data from Bulk RNA and Single-Nucleus RNA Sequencing Analyses

Identification and Validation of Neutrophil Extracellular Traps-Associated Genes in Diabetic Kidney Disease: Integration Data from Bulk RNA and Single-Nucleus RNA Sequencing Analyses

Assessing the potential of DZIP1L gene in autosomal recessive polycystic kidney disease gene therapy

Assessing the potential of <i>DZIP1L</i> gene in autosomal recessive polycystic kidney disease gene therapy

Landscape of infiltrating immune cells and related genes in diabetic kidney disease.

Diabetic kidney disease (DKD) is one of the prominent microvascular complications of diabetes and the leading cause of end-stage renal disease. Inflammation plays a crucial role in the development and progression of DKD. Currently, only a few studies depict the landscape of infiltrating immune cells and their potential regulatory network in DKD. To gain a better understanding of the role of immune cells in the renal microenvironment, we sought to reveal the profile of infiltrating immune cells and their potential regulatory network in DKD. We obtained the transcriptomes and the corresponding clinical data of 19 DKD and 25 control samples from the Gene Expression Omnibus and Nephroseq databases, respectively. Thereafter, we conducted an analysis on the infiltrating immune cells and identified immune-related differentially expressed genes through bioinformatics. Finally, correlation analyses among immune cells, immune genes, and clinical manifestations were performed, and differentially infiltrating immune cell subsets were verified through multiplex immunofluorescence staining. We demonstrated the landscape of infiltrating immune cells in patients with DKD and identified the top five hub immune regulatory genes (C3, IL7R, TYROBP, BMP2, and CXCL6). Three of the core genes (C3, BMP2, and CXCL6) were significantly correlated with the estimated glomerular filtration rate. Through multiplex immunofluorescence staining, we verified that macrophage numbers were remarkably elevated, whereas Treg cells were remarkably reduced in diabetic kidney tissues. Th2 cells were scarce in the kidney tissue. Collectively, our findings shed light on new, possible therapeutic strategies for DKD, from an immune microenvironment perspective.

Identifying key genes for diabetic kidney disease by bioinformatics analysis

BackgroundThere are no reliable molecular targets for early diagnosis and effective treatment in the clinical management of diabetic kidney disease (DKD). To identify novel gene factors underlying the progression of DKD.MethodsThe public transcriptomic datasets of the alloxan-induced DKD model and the streptozotocin-induced DKD model were retrieved to perform an integrative bioinformatic analysis of differentially expressed genes (DEGs) shared by two experimental animal models. The dominant biological processes and pathways associated with DEGs were identified through enrichment analysis. The expression changes of the key DEGs were validated in the classic db/db DKD mouse model.ResultsThe downregulated and upregulated genes in DKD models were uncovered from GSE139317 and GSE131221 microarray datasets. Enrichment analysis revealed that metabolic process, extracellular exosomes, and hydrolase activity are shared biological processes and molecular activity is altered in the DEGs. Importantly, Hmgcs2, angptl4, and Slco1a1 displayed a consistent expression pattern across the two DKD models. In the classic db/db DKD mice, Hmgcs2 and angptl4 were also found to be upregulated while Slco1a1 was downregulated in comparison to the control animals.ConclusionsIn summary, we identified the common biological processes and molecular activity being altered in two DKD experimental models, as well as the novel gene factors (Hmgcs2, Angptl4, and Slco1a1) which may be implicated in DKD. Future works are warranted to decipher the biological role of these genes in the pathogenesis of DKD.

Hypoxia controls expression of kidney-pathogenic MUC1 variants.

The interplay between genetic and environmental factors influences the course of chronic kidney disease (CKD). In this context, genetic alterations in the kidney disease gene MUC1 (Mucin1) predispose to the development of CKD. These variations comprise the polymorphism rs4072037, which alters splicing of MUC1 mRNA, the length of a region with variable number of tandem repeats (VNTR), and rare autosomal-dominant inherited dominant-negative mutations in or 5' to the VNTR that causes autosomal dominant tubulointerstitial kidney disease (ADTKD-MUC1). As hypoxia plays a pivotal role in states of acute and chronic kidney injury, we explored the effects of hypoxia-inducible transcription factors (HIF) on the expression of MUC1 and its pathogenic variants in isolated primary human renal tubular cells. We defined a HIF-binding DNA regulatory element in the promoter-proximal region of MUC1 from which hypoxia or treatment with HIF stabilizers, which were recently approved for an anti-anemic therapy in CKD patients, increased levels of wild-type MUC1 and the disease-associated variants. Thus, application of these compounds might exert unfavorable effects in patients carrying MUC1 risk variants.

#3812 ARE KIDNEY CYSTS MORE COMMON IN PEOPLE WITH COL4A3/COL4A4 PATHOGENIC VARIANTS?

Abstract Background and Aims Individuals with pathogenic heterozygous variants in the COL4A3/COL4A4 genes are usually asymptomatic or present only with microhaematuria, although some may develop proteinuria and chronic kidney disease (CKD). Simple renal cysts are common in healthy individuals, with an increasing incidence with age and CKD grade. A possible association between pathogenic variants of collagen type IV and renal cysts has been described. This study investigates the presence of renal cysts in a large cohort of individuals with heterozygous pathogenic variants in COL4A3/COL4A4. Method We evaluated the presence of kidney cysts, kidney size and lithiasis by ultrasound in 162 individuals with pathogenic variants in COL4A3/COL4A4 without kidney replacement therapy. The correlation between kidney cysts and age, proteinuria, eGFR, causing gene and type of variant, was analysed. Genetic testing had been performed in index cases by next generation sequencing (NGS) of a kidney-disease gene panel containing more than 400 genes including COL4A3, COL4A4 and COL4A5 genes. Results 153 patients with a heterozygous disease-causing variant in COL4A3 or COL4A4 and 9 patients with digenic/complex inheritance were included. The mean age at renal ultrasound was 46.19 years (SD 14.93) and the mean eGFR was 75 ml/min/1.73 m2 (SD 35 ml/min/1.73 m2). Renal cysts were present in 50% of patients (81/162) and were bilateral in 30.25%. The mean age of patients with renal cysts was 53.26 years vs. 39.12 years for those without, and the mean eGFR was 60ml/min/1.73 m2 vs. 89ml/min/1.73 m2 for patients with and without renal cysts. Only 2.5% (4/162) of patients had renal lithiasis. The mean kidney size was 104.05 mm (SD 13.86 mm) for the right kidney and 104.98 mm (SD 13.94 mm) for the left kidney. Cystic nephromegaly was observed in 3.7% (6/162). No correlation was found between renal cysts and gender (p = 0.632). Age and CKD stage had a positive correlation with the development of renal cysts (p = &amp;lt;0.001) (Tables 1 and 2). Proteinuria was more common in individuals with renal cysts 61% vs 39% (p = 0.012), but was related to age and CKD stage. The presence of a kidney cyst did not correlate with the mutated gene or the type of variant. Conclusion Individuals with COL4A3/COL4A4 pathogenic variants develop kidney cysts at a higher rate than age-matched healthy individuals, and their presence is also related to ageing, as in the general population. Gender is not relevant for the development of renal cysts, in contrast to the general population cohorts. Proteinuria and CKD grade correlate with the development of renal cysts but nephromegaly is rare. Renal cysts in heterozygous carriers of COL43 or COL4A4 pathogenic variants are common but have no clinical consequences.

Kidney transcriptome and cystic kidney disease genes in zebrafish.

Introduction: Polycystic kidney disease (PKD) is a condition where fluid filled cysts form on the kidney which leads to overall renal failure. Zebrafish has been recently adapted to study polycystic kidney disease, because of its powerful embryology and genetics. However, there are concerns on the conservation of this lower vertebrate in modeling polycystic kidney disease. Methods: Here, we aim to assess the molecular conservation of zebrafish by searching homologues polycystic kidney disease genes and carrying transcriptome studies in this animal. Results and Discussion: We found that out of 82 human cystic kidney disease genes, 81 have corresponding zebrafish homologs. While 75 of the genes have a single homologue, only 6 of these genes have two homologs. Comparison of the expression level of the transcripts enabled us to identify one homolog over the other homolog with >70% predominance, which would be prioritized for future experimental studies. Prompted by sexual dimorphism in human and rodent kidneys, we studied transcriptome between different sexes and noted significant differences in male vs. female zebrafish, indicating that sex dimorphism also occurs in zebrafish. Comparison between zebrafish and mouse identified 10% shared genes and 38% shared signaling pathways. String analysis revealed a cluster of genes differentially expressed in male vs. female zebrafish kidneys. In summary, this report demonstrated remarkable molecular conservation, supporting zebrafish as a useful animal model for cystic kidney disease.

Transcription factor Ap2b regulates the mouse autosomal recessive polycystic kidney disease genes, Pkhd1 and Cys1.

Transcription factor Ap2b (TFAP2B), an AP-2 family transcription factor, binds to the palindromic consensus DNA sequence, 5'-GCCN3-5GGC-3'. Mice lacking functional Tfap2b gene die in the perinatal or neonatal period with cystic dilatation of the kidney distal tubules and collecting ducts, a phenotype resembling autosomal recessive polycystic kidney disease (ARPKD). Human ARPKD is caused by mutations in PKHD1, DZIP1L, and CYS1, which are conserved in mammals. In this study, we examined the potential role of TFAP2B as a common regulator of Pkhd1 and Cys1. We determined the transcription start site (TSS) of Cys1 using 5' Rapid Amplification of cDNA Ends (5'RACE); the TSS of Pkhd1 has been previously established. Bioinformatic approaches identified cis-regulatory elements, including two TFAP2B consensus binding sites, in the upstream regulatory regions of both Pkhd1 and Cys1. Based on reporter gene assays performed in mouse renal collecting duct cells (mIMCD-3), TFAP2B activated the Pkhd1 and Cys1 promoters and electromobility shift assay (EMSA) confirmed TFAP2B binding to the in silico identified sites. These results suggest that Tfap2b participates in a renal epithelial cell gene regulatory network that includes Pkhd1 and Cys1. Disruption of this network impairs renal tubular differentiation, causing ductal dilatation that is the hallmark of recessive PKD.

Transcriptional programming of pathogenic genes in polycystic kidney disease

Transcriptional dysregulation is a prominent contributor to the pathogenesis of autosomal dominant polycystic kidney disease. Lakhia etal. identified an enhancer landscape associated with disease genes and its pathologic role in autosomal dominant polycystic kidney disease to understand cyst formation. This commentary discusses these findings reported by Lakhia etal. in the broader contexts of transcriptional programming and the identification of potential autosomal dominant polycystic kidney disease therapeutic targets.

A Low-Cost Sequencing Platform for Rapid Genotyping in ADPKD and its Impact on Clinical Care

Autosomal-dominant polycystic kidney disease (ADPKD) is the most common genetic cause of kidney failure. Because of the heterogeneity in disease progression in ADPKD, parameters predicting future outcome are important. The disease-causing genetic variant is one of these parameters. A multiplex polymerase chain reaction (PCR)-based panel (MPP) was established for analysis of 6 polycystic kidney disease (PKD) genes (PKD1, PKD2, HNF1B, GANAB, DZIP1L, and PKHD1) in 441 patients with ADPKD. Selected patients were additionally sequenced using Sanger sequencing or a custom enrichment-based gene panel. Results were combined with clinical characteristics to assess the impact of genetic data on clinical decision-making. Variants of unclear significance (VUS) were considered diagnostic based on a classic ADPKD clinical phenotype. Using the MPP, disease-causing variants were detected in 65.3% of patients. Sanger sequencing and the custom gene panel in 32 patients who were MPP-negative revealed 20 variants missed by MPP, (estimated overall false negative rate 24.6%, false-positive rate 9.4%). Combining clinical and genetic data revealed that knowledge of the genotype could have impacted the treatment decision in 8.2% of patients with a molecular genetic diagnosis. Sequencing only the PKD1 pseudogene homologous region in MPP-negative patients resulted in an acceptable false-negative rate of 3.28%. The MPP yields rapid genotype information at lower costs and allows for simple extension of the panel for new disease genes. Additional sequencing of the PKD1 pseudogene homologous region is required in negative cases. Access to genotype information even in settings with limited resources is important to allow for optimal patient counseling in ADPKD.

Tracking N- and C-termini of C. elegans polycystin-1 reveals their distinct targeting requirements and functions in cilia and extracellular vesicles.

The cilium acts as an antenna receiving and sending signals, the latter via extracellular vesicles (EVs). In C. elegans and mammals, the Autosomal Dominant Polycystic Kidney Disease (ADPKD) gene products polycystin-1 (PC1) and polycystin-2 (PC2) localize to both cilia and EVs, act in the same genetic pathway, and function in a sensory capacity, suggesting ancient conservation. However, the functions of the polycystins on cilia and EVs remain enigmatic. We used our C. elegans model and endogenously fluorescent-tagged LOV-1/polycystin-1 to study LOV-1 processing, trafficking, transport, EV biogenesis, and function in living animals. Super resolution, real time imaging reveals that LOV-1 is processed into N-terminal (NTM) and C-terminal (CTM) forms via a conserved GPCR proteolytic site (GPS). The LOV-1 NTM is secreted into the extracellular matrix and not localized to ciliary tip EVs. In contrast, LOV-1 CTM and PKD-2 are co-trafficked, co-transported, and co-localized in cilia and on environmentally released ciliary EVs. LOV-1 CTM requires PKD-2 for ciliary EV localization, while PKD-2 localizes to ciliary EVs independent of LOV-1. We find that LOV-1 but not PKD-2 is required for chemosensation of an ascaroside mating pheromone. These findings indicate that the polycystins LOV-1 and PKD-2 function together and independently and provide insight to how cargo is selected and packaged in ciliary EVs.