title: Structure-activity relationship of piperine and its synthetic amide analogs for therapeutic potential to prevent experimentally induced ER stress in vitro.
abstract: Endoplasmic reticulum (ER) is the key organelle involved in protein folding and maturation. Emerging studies implicate the role of ER stress in the development of chronic kidney disease. Thus, there is an urgent need for compounds that could ameliorate ER stress and prevent CKD. Piperine and its analogs have been reported to exhibit multiple pharmacological activities; however, their efficacy against ER stress in kidney cells has not been studied yet. Hence, the goal of this study was to synthesize amide-substituted piperine analogs and screen them for pharmacological activity to relieve ER stress using an in vitro model of tunicamycin-induced ER stress using normal rat kidney (NRK-52E) cells. Five amide-substituted piperine analogs were synthesized and their chemical structures were elucidated by pertinent spectroscopic techniques. An in vitro model of ER stress was developed using tunicamycin, and the compounds of interest were screened for their effect on cell viability, and the expression of ER chaperone GRP78, the pro-apoptotic ER stress marker CHOP, and apoptotic caspases 3 and 12 (via western blotting). Our findings indicate that exposure to tunicamycin (0.5 μg/mL) for 2 h induces the expression of GRP78 and CHOP, and apoptotic markers (caspase-3 and caspase-12) and causes a significant reduction in renal cell viability. Pre-treatment of cells with piperine and its cyclohexylamino analog decreased the tunicamycin-induced upregulation of GRP78 and CHOP and cell death. Taken together, our findings demonstrate that piperine and its analogs differentially regulate ER stress, and thus represent potential therapeutic agents to treat ER stress-related renal disorders. Graphical Abstract Piperine (PIP) reduces the expression of ER stress markers (GRP78 and CHOP) induced by pathologic stimuli and consequently decreases the activation of apoptotic caspase-12 and caspase-3; all of which contributes to its chemical chaperone and cytoprotective properties to protect renal cells against ER stress and ER stress-induced cell death, and would ultimately prevent the development of chronic kidney disease.
authors.affiliation: College of Pharmacy, Qatar University, PO Box 2713, Doha, Qatar.
authors.forename: Ayat S
authors.initials: AS
authors.lastname: Hammad
authors.affiliation: College of Pharmacy, Qatar University, PO Box 2713, Doha, Qatar.
authors.forename: Sreenithya
authors.initials: S
authors.lastname: Ravindran
authors.affiliation: College of Pharmacy, Qatar University, PO Box 2713, Doha, Qatar.
authors.forename: Ashraf
authors.initials: A
authors.lastname: Khalil
authors.affiliation: College of Pharmacy, Qatar University, PO Box 2713, Doha, Qatar. shankar.munusamy@qu.edu.qa.
authors.forename: Shankar
authors.identifier: 0000-0002-2023-7705
authors.initials: S
authors.lastname: Munusamy
mesh_terms: D000470:Alkaloids / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D000577:Amides / Q000138:chemical synthesis / Q000737:chemistry*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D052117:Benzodioxoles / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D053454:Caspase 12 / Q000378:metabolism; D053148:Caspase 3 / Q000378:metabolism; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004721:Endoplasmic Reticulum / Q000378:metabolism; D000091342:Endoplasmic Reticulum Chaperone BiP; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects*; D005231:Fatty Acids, Unsaturated / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D006360:Heat-Shock Proteins / Q000378:metabolism; D010880:Piperidines / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D053284:Polyunsaturated Alkamides / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D051381:Rats; D013329:Structure-Activity Relationship; D051742:Transcription Factor CHOP / Q000378:metabolism; D014415:Tunicamycin / Q000494:pharmacology; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D000470:Alkaloids; D000577:Amides; D052117:Benzodioxoles; D000091342:Endoplasmic Reticulum Chaperone BiP; D005231:Fatty Acids, Unsaturated; D006360:Heat-Shock Proteins; D010880:Piperidines; D053284:Polyunsaturated Alkamides; D014415:Tunicamycin; D051742:Transcription Factor CHOP; D053454:Caspase 12; D053148:Caspase 3; C017637:piperic acid; C008922:piperine
keywords: Amide piperine analogs; Chronic kidney disease; ER stress; NRK-52E; Piperine; Tunicamycin