Mechanobiological proximal tubular defects in ARC syndrome: A VPS33B CRISPR knockout study

ARC syndrome (arthrogryposis-renal dysfunction-cholestasis) is a rare autosomal recessive multisystem disorder affecting the kidneys. The disease is caused by mutations in either VPS33B or VIPAS39 . ARC syndrome is currently incurable, with patients rarely surviving beyond their first year of life. The renal component of this disorder is characterised by proximal tubular dysfunction. Here, a proximal tubular cell line, RPTEC-TERT1, was CRISPR-edited to knock out (KO) VPS33B expression. Characterisation of VPS33B -KO cells was performed using brightfield imaging, immunostaining, RNA sequencing, and cell detachment assays. The VPS33B -KO RPTEC-TERT1 cells demonstrated a ‘peeling’ phenotype and altered cell adhesion. This, along with altered transcription of genes associated with cell adhesion, suggests that VPS33B KO results in cell-matrix attachment defects. These findings provide the first insights into the cause of proximal tubular dysfunction in ARC syndrome.