Ultrabright Plasmonic-Fluor Nanolabel-Enabled Detection of a Urinary ER Stress Biomarker in Autosomal Dominant Tubulointerstitial Kidney Disease

Am J Physiol Renal Physiol. 2021 Jul 12. doi: 10.1152/ajprenal.00231.2021. Online ahead of print.ABSTRACTAutosomal dominant tubulointerstitial kidney disease (ADTKD)-uromodulin (UMOD) is the most common non-polycystic genetic kidney disease, but it remains unrecognized due to its clinical heterogeneity and lack of screening test. Moreover, clinical feature being a poor predictor of the disease outcome further highlights the need for development of mechanistic biomarkers in ADTKD. However, low abundant urinary proteins secreted by thick ascending limb (TAL) cells, where UMOD is synthesized, have posed a challenge on detection of biomarkers in ADTKD-UMOD. In the CRISPR/Cas9-generated murine model and patients with ADTKD-UMOD, we find that immunoglobulin heavy chain-binding protein (BiP), an ER chaperone, was exclusively upregulated by mutant UMOD in TAL and easily detected by Western blot in the urine at an early stage of disease. However, even the most sensitive ELISA failed to detect urinary BiP in affected individuals. We therefore developed an ultrasensitive, plasmon-enhanced fluorescence-linked immunosorbent assay (p-FLISA) to quantify urinary BiP concentration by harnessing the newly invented ultrabright fluorescent nanoconstruct, termed "plasmonic fluor" (Nat Biomed Eng 2020). p-FLISA demonstrated that urinary BiP excretion was significantly elevated in ADTKD-UMOD patients compared with unaffected controls, which may have potential utility in risk stratification, disease...
Source: Am J Physiol Renal P... - Category: Urology & Nephrology Authors: Source Type: research