Intracellular accumulation of misfolded proteins causes toxic proteinopathies, diseases without targeted therapies. Mucin 1 kidney disease (MKD) results from a frameshift mutation in the MUC1 gene (MUC1-fs). Here, we show that MKD is a toxic proteinopathy. Intracellular MUC1-fs accumulation activated the ATF6 unfolded protein response (UPR) branch. We identified BRD4780, a small molecule that clears MUC1-fs from patient cells, from kidneys of knockin mice and from patient kidney organoids. MUC1-fs is trapped in TMED9 cargo receptor-containing vesicles of the early secretory pathway. BRD4780 binds TMED9, releases MUC1-fs, and re-routes it for lysosomal degradation, an effect phenocopied by TMED9 deletion. Our findings reveal BRD4780 as a promising lead for the treatment of MKD and other toxic proteinopathies. Generally, we elucidate a novel mechanism for the entrapment of misfolded proteins by cargo receptors and a strategy for their release and anterograde trafficking to the lysosome.

• MeSH
• benzamidy chemie   metabolismus   farmakologie   MeSH
• epitelové buňky cytologie   metabolismus   MeSH
• imidazolinové receptory antagonisté a inhibitory   genetika   metabolismus   MeSH
• indukované pluripotentní kmenové buňky cytologie   metabolismus   MeSH
• ledviny cytologie   metabolismus   patologie   MeSH
• lidé MeSH
• lyzozomy metabolismus   MeSH
• malá interferující RNA metabolismus   MeSH
• mucin 1 chemie   genetika   metabolismus   MeSH
• myši transgenní MeSH
• myši MeSH
• nemoci ledvin metabolismus   patologie   MeSH
• posunová mutace MeSH
• RNA interference MeSH
• signální dráha UPR účinky léků   MeSH
• transkripční faktor ATF6 metabolismus   MeSH
• vezikulární transportní proteiny chemie   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Mucin-1 kidney disease, previously described as medullary cystic kidney disease type 1 (MCKD1, OMIM 174000), is an autosomal dominant tubulointerstitial kidney disease recently shown to be caused by a single-base insertion within the variable number tandem repeat region of the MUC1 gene. Because of variable age of disease onset and often subtle signs and symptoms, clinical diagnosis of mucin-1 kidney disease and differentiation from other forms of hereditary kidney disease have been difficult. The causal insertion resides in a variable number tandem repeat region with high GC content, which has made detection by standard next-generation sequencing impossible to date. The inherently difficult nature of this mutation required an alternative method for routine detection and clinical diagnosis of the disease. We therefore developed and validated a mass spectrometry-based probe extension assay with a series of internal controls to detect the insertion event using 24 previously characterized positive samples from patients with mucin-1 kidney disease and 24 control samples known to be wild type for the variant. Validation results indicate an accurate and reliable test for clinically establishing the molecular diagnosis of mucin-1 kidney disease with 100% sensitivity and specificity across 275 tests called.

• MeSH
• diagnostické techniky molekulární * MeSH
• genotyp MeSH
• hmotnostní spektrometrie metody   normy   MeSH
• lidé MeSH
• mucin 1 genetika   MeSH
• mutace * MeSH
• polycystické ledviny autozomálně dominantní diagnóza   genetika   MeSH
• průběh práce MeSH
• reprodukovatelnost výsledků MeSH
• senzitivita a specificita MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH