title: Analysis of the potency of various low molecular weight chemical chaperones to prevent protein aggregation.
abstract: Newly translated proteins must undergo proper folding to ensure their function. To enter a low energy state, misfolded proteins form aggregates, which are associated with many degenerative diseases, such as Huntington's disease and chronic kidney disease (CKD). Recent studies have shown the use of low molecular weight chemical chaperones to be an effective method of reducing protein aggregation in various cell types. This study demonstrates a novel non-biased assay to assess the molecular efficacy of these compounds at preventing protein misfolding and/or aggregation. This assay utilizes a thioflavin T fluorescent stain to provide a qualitative and quantitative measure of protein misfolding within cells. The functionality of this method was first assessed in renal proximal tubule epithelial cells treated with various endoplasmic reticulum (ER) stress inducers. Once established in the renal model system, we analyzed the ability of some known chemical chaperones to reduce ER stress. A total of five different compounds were selected: 4-phenylbutyrate (4-PBA), docosahexaenoic acid (DHA), tauroursodeoxycholic acid, trehalose, and glycerol. The dose-dependent effects of these compounds at reducing thapsigargin-induced ER stress was then analyzed, and used to determine their EC50values. Of the chaperones, 4-PBA and DHA provided the greatest reduction of ER stress and did so at relatively low concentrations. Upon analyzing the efficiency of these compounds and their corresponding structures, it was determined that chaperones with a localized hydrophilic, polar end followed by a long hydrophobic chain, such as 4-PBA and DHA, were most effective at reducing ER stress. This study provides some insight into the use of low molecular weight chemical chaperones and may serve as the first step towards developing new chaperones of greater potency thereby providing potential treatments for diseases caused by protein aggregation.
authors.affiliation: Department of Biochemistry, McMaster University, 1280 Main St W, Hamilton, ON L8S 4L8, Canada.
authors.forename: Chandak
authors.initials: C
authors.lastname: Upagupta
authors.affiliation: Department of Medicine, Division of Nephrology, McMaster University, St. Joseph's Healthcare Hamilton, 50 Charlton Ave E, Hamilton, ON L8N 4A6, Canada.
authors.forename: Rachel E
authors.initials: RE
authors.lastname: Carlisle
authors.affiliation: Department of Medicine, Division of Nephrology, McMaster University, St. Joseph's Healthcare Hamilton, 50 Charlton Ave E, Hamilton, ON L8N 4A6, Canada. Electronic address: jdickhou@stjosham.on.ca.
authors.forename: Jeffrey G
authors.initials: JG
authors.lastname: Dickhout
mesh_terms: D052160:Benzothiazoles; D002460:Cell Line; D004281:Docosahexaenoic Acids / Q000737:chemistry / Q000494:pharmacology; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects; D004847:Epithelial Cells / Q000187:drug effects* / Q000378:metabolism; D005990:Glycerol / Q000737:chemistry / Q000494:pharmacology; D006801:Humans; D007687:Kidney Tubules, Proximal / Q000166:cytology; D008970:Molecular Weight; D010654:Phenylbutyrates / Q000737:chemistry / Q000494:pharmacology; D066329:Protein Aggregates / Q000187:drug effects*; D066263:Protein Aggregation, Pathological / Q000517:prevention & control*; D017510:Protein Folding / Q000187:drug effects; D013194:Staining and Labeling / Q000379:methods; D013655:Taurochenodeoxycholic Acid / Q000737:chemistry / Q000494:pharmacology; D019284:Thapsigargin / Q000494:pharmacology; D013844:Thiazoles / Q000737:chemistry; D014199:Trehalose / Q000737:chemistry / Q000494:pharmacology; D056811:Unfolded Protein Response / Q000187:drug effects; D015262:Xenobiotics / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D052160:Benzothiazoles; D010654:Phenylbutyrates; D066329:Protein Aggregates; D013844:Thiazoles; D015262:Xenobiotics; C009462:thioflavin T; D004281:Docosahexaenoic Acids; D013655:Taurochenodeoxycholic Acid; C031655:ursodoxicoltaurine; D019284:Thapsigargin; C075773:4-phenylbutyric acid; D014199:Trehalose; D005990:Glycerol
keywords: 4-phenylbutyrate; Chronic kidney disease; Docosahexaenoic acid; Endoplasmic reticulum stress; Low molecular weight chemical chaperone; Thioflavin T