Search bioRxiv⌕ Search

bioRxiv · 10.1101/2022.03.14.483768

Base editing derived models of human WDR34 and WDR60 disease alleles replicate retrograde IFT and hedgehog signaling defects and suggest disturbed Golgi protein transport

Abstract

Cytoplasmic Dynein-2 or IFT-dynein is the only known retrograde motor for intraflagellar transport, enabling protein trafficking from the ciliary tip to the base. Dysfunction of WDR34 and WDR60, the two intermediate chains of this complex, causes Short Rib Thoracic Dystrophy (SRTD), human skeletal chondrodysplasias with high lethality. Complete loss of function of WDR34 or WDR60 is lethal in vertebrates and individuals with SRTD carry at least one putative hypomorphic missense allele. Gene knockout is therefore not suitable to study the effect of these human missense disease alleles. Using CRISPR single base editors, we recreated three different patient missense alleles in cilia-APEX-IMCD3 cells. Consistent with previous findings in dynein-2 full loss of function models and patient fibroblasts, mutant cell lines showed hedgehog signaling defects as well as disturbed retrograde IFT. Transcriptomics analysis revealed differentially regulated expression of genes associated with various biological processes, including G-protein-coupled receptor signaling as well extracellular matrix composition, endochondral bone growth and chondrocyte development. Further, we also observed differential regulation of genes associated with Golgi intracellular transport, including downregulation of Rab6b, a GTPase involved in Golgi-ER retrograde protein trafficking and interacting with components of cytoplasmic dynein-1, in mutant ciliated and non-ciliated clones compared to controls. In addition to providing cellular model systems enabling investigations of the effect of human SRTD disease alleles, our findings indicate non-ciliary functions for WDR34 and WDR60 in addition to the established roles as components of the retrograde IFT motor complex in cilia.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Antony, D., Guelec, E. Y., Bakey, Z., Schuele, I., Kim, G.-J., Brunner, H. G., Arnold, S. J., Schmidts, M.. 2022-03-14. Base editing derived models of human WDR34 and WDR60 disease alleles replicate retrograde IFT and hedgehog signaling defects and suggest disturbed Golgi protein transport. https://doi.org/10.1101/2022.03.14.483768

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

KEEP EXPLORING

Related preprints

Large language model-based bibliometric evaluation of population descriptors in human genetics

As the use of population descriptors such as race, ethnicity, and ancestry have become increasingly common in modern genetics research, there have been growing calls to critically examine their use. Most notably, in 2023, the National Academies of Science, Engineering, and Medicine (NASEM) published a report titled Using Population Descriptors in Genetics and Genomics Research: A New Framework for an Evolving Field, which included eight specific and actionable recommendations for researchers to implement the ethical and accurate use of population descriptors in genetic research. Here, we use the 2023 NASEM report as a benchmark to analyze the use of population descriptors in genome-wide association studies (GWAS). We develop a general toolkit for large language model-based bibliometrics, operationalize the report's recommendations into an evaluation framework, and apply this framework to evaluate all 4,007 papers from the GWAS Catalog published between 2007 and 2025 with full text available on PubMedCentral. We find significant improvements in adherence to NASEM report recommendations over time. However, most improvements predate the publication of the NASEM report itself, suggesting the report functioned primarily as a synthesis of existing best practices rather than a catalyst for change. We conclude by highlighting opportunities for growth in the field of human genetics.

genetics↗

Mitigating biases of rescaling in forward-in-time population genetic simulations

Forward-in-time population genetic simulations are widely used in evolutionary analyses, but simulating large populations and long genomic regions remains computationally demanding. To reduce this cost, parameter rescaling is widely employed, in which the original evolutionary process is approximated by one with a smaller population size and fewer generations. Recently, several studies using the SLiM simulator have raised concerns about the accuracy of this rescaling approach. In this study, we show that many of the biases reported in these studies can be mitigated by using a different simulation algorithm. These results reveal that the accuracy of parameter rescaling depends on how well the simulation algorithm preserves diffusion-limit properties under rescaling.

genetics↗

OPA1 controls mitochondrial dysfunction-driven liver fibrosis in MASLD

Progressive hepatic fibrosis is the principal determinant of morbidity and mortality in metabolic dysfunction-associated steatotic liver disease and steatohepatitis (MASLD/MASH). Mitochondrial dysfunction is a hallmark of MASH, and the release of mitochondrial damage-associated molecular patterns (mito-DAMPs) from injured hepatocytes can promote fibrosis. However, how mitochondrial dynamics and quality control shape the fibrotic response in MASLD/MASH remains unclear. Here, through large-scale genomic analyses of mitochondrial genes governing mitophagy, fusion and fission in human MASLD, with a power-equivalent sample size of approximately 700,000 individuals, we identify a strong association between hepatic fibrosis and the mitochondrial fusion factor dynamin-like GTPase optic atrophy 1 (OPA1). OPA1 transcripts and protein abundance in the liver epithelium were progressively dysregulated with advancing fibrosis. In mice, hepatocyte-specific OPA1 loss alone was sufficient to induce hepatic stellate cell activation and fibrosis in zone 3, promoted the release of mito-DAMPs into the circulation and exacerbated fibrosis in experimental MASH. These findings identify OPA1 as a central regulator of the hepatic fibrotic response and connect defective mitochondrial homeostasis to mito-DAMP release, hepatic stellate cell activation and fibrosis in MASLD.

genetics↗