ORCID Profile
0000-0001-5893-6002
Current Organisation
The Hong Kong Polytechnic University
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Publisher: American Chemical Society (ACS)
Date: 10-2014
DOI: 10.1021/PR500558Y
Publisher: Elsevier BV
Date: 10-2018
Publisher: Springer Science and Business Media LLC
Date: 30-03-2023
DOI: 10.1038/S42003-023-04725-1
Abstract: TGFBI-related corneal dystrophy (CD) is characterized by the accumulation of insoluble protein deposits in the corneal tissues, eventually leading to progressive corneal opacity. Here we show that ATP-independent amyloid-β chaperone L-PGDS can effectively disaggregate corneal amyloids in surgically excised human cornea of TGFBI-CD patients and release trapped amyloid hallmark proteins. Since the mechanism of amyloid disassembly by ATP-independent chaperones is unknown, we reconstructed atomic models of the amyloids self-assembled from TGFBIp-derived peptides and their complex with L-PGDS using cryo-EM and NMR. We show that L-PGDS specifically recognizes structurally frustrated regions in the amyloids and releases those frustrations. The released free energy increases the chaperone’s binding affinity to amyloids, resulting in local restructuring and breakage of amyloids to protofibrils. Our mechanistic model provides insights into the alternative source of energy utilized by ATP-independent disaggregases and highlights the possibility of using these chaperones as treatment strategies for different types of amyloid-related diseases.
Publisher: American Society for Pharmacology & Experimental Therapeutics (ASPET)
Date: 21-10-2015
Abstract: Dronedarone is an antiarrhythmic agent approved in 2009 for the treatment of atrial fibrillation. An in-house preliminary study demonstrated that dronedarone inhibits cytochrome P450 (CYP) 3A4 and 3A5 in a time-dependent manner. This study aimed to investigate the inactivation of CYP450 by dronedarone. We demonstrated for the first time that both dronedarone and its main metabolite N-desbutyl dronedarone (NDBD) inactivate CYP3A4 and CYP3A5 in a time-, concentration-, and NADPH-dependent manner. For the inactivation of CYP3A4, the inactivator concentration at the half-maximum rate of inactivation and inactivation rate constant at an infinite inactivator concentration are 0.87 µM and 0.039 minute(-1), respectively, for dronedarone, and 6.24 µM and 0.099 minute(-1), respectively, for NDBD. For CYP3A5 inactivation, the inactivator concentration at the half-maximum rate of inactivation and inactivation rate constant at an infinite inactivator concentration are 2.19 µM and 0.0056 minute(-1) for dronedarone and 5.45 µM and 0.056 minute(-1) for NDBD. The partition ratios for the inactivation of CYP3A4 and CYP3A5 by dronedarone are 51.1 and 32.2, and the partition ratios for the inactivation of CYP3A4 and CYP3A5 by NDBD are 35.3 and 36.6. Testosterone protected both CYP3A4 and CYP3A5 from inactivation by dronedarone and NDBD. Although the presence of Soret peak confirmed the formation of a quasi-irreversible metabolite-intermediate complex between dronedarone/NDBD and CYP3A4/CYP3A5, partial recovery of enzyme activity by potassium ferricyanide illuminated an alternative irreversible mechanism-based inactivation (MBI). MBI of CYP3A4 and CYP3A5 was further supported by the discovery of glutathione adducts derived from the quinone oxime intermediates of dronedarone and NDBD. In conclusion, dronedarone and NDBD inactivate CYP3A4 and CYP3A5 via unique dual mechanisms of MBI and formation of the metabolite-intermediate complex. Our novel findings contribute new knowledge for future investigation of the underlying mechanisms associated with dronedarone-induced hepatotoxicity and clinical drug-drug interactions.
Publisher: Elsevier BV
Date: 05-2016
DOI: 10.1016/J.BCP.2016.03.005
Abstract: Dronedarone, a multiple ion channel blocker is prescribed for the treatment of paroxysmal and persistent atrial fibrillation. While dronedarone does not precipitate toxicities like its predecessor amiodarone, its clinical use has been associated with idiosyncratic hepatic and cardiac adverse effects and drug-drug interactions (DDIs). As dronedarone is a potent mechanism-based inactivator of CYP3A4 and CYP3A5, a question arose if it exerts a similar inhibitory effect on CYP2J2, a prominent cardiac CYP450 enzyme. In this study, we demonstrated that CYP2J2 is reversibly inhibited by dronedarone (Ki=0.034 μM), amiodarone (Ki=4.8μM) and their respective pharmacologically active metabolites namely N-desbutyldronedarone (NDBD) (Ki=0.55 μM) and N-desethylamiodarone (NDEA) (Ki=7.4 μM). Moreover, time-, concentration- and NADPH-dependent irreversible inactivation of CYP2J2 was investigated where inactivation kinetic parameters (KI, kinact) and partition ratio (r) of dronedarone (0.05 μM, 0.034 min(-1), 3.3), amiodarone (0.21 μM, 0.015 min(-1), 20.7) and NDBD (0.48 μM, 0.024 min(-1), 21.7) were observed except for NDEA. The absence of the characteristic Soret peak, lack of recovery of CYP2J2 activity upon dialysis, and biotransformation of dronedarone and NDBD to quinone-oxime reactive metabolites further confirmed the irreversible inactivation of CYP2J2 by dronedarone and NDBD is via the covalent adduction of CYP2J2. Our novel findings illuminate the possible mechanisms of DDIs and cardiac adverse effects due to both reversible inhibition and irreversible inactivation of CYP2J2 by dronedarone, amiodarone and their active metabolites.
Publisher: Springer Science and Business Media LLC
Date: 06-04-2016
DOI: 10.1038/NCOMMS11008
Abstract: Myopia is the most common human eye disorder and it results from complex genetic and environmental causes. The rapidly increasing prevalence of myopia poses a major public health challenge. Here, the CREAM consortium performs a joint meta-analysis to test single-nucleotide polymorphism (SNP) main effects and SNP × education interaction effects on refractive error in 40,036 adults from 25 studies of European ancestry and 10,315 adults from 9 studies of Asian ancestry. In European ancestry in iduals, we identify six novel loci ( FAM150B-ACP1 , LINC00340 , FBN1 , DIS3L-MAP2K1 , ARID2-SNAT1 and SLC14A2 ) associated with refractive error. In Asian populations, three genome-wide significant loci AREG , GABRR1 and PDE10A also exhibit strong interactions with education ( P .5 × 10 −5 ), whereas the interactions are less evident in Europeans. The discovery of these loci represents an important advance in understanding how gene and environment interactions contribute to the heterogeneity of myopia.
Publisher: American Chemical Society (ACS)
Date: 19-08-2015
DOI: 10.1021/ACS.JPROTEOME.5B00443
Abstract: "Dry eye" is a multifactorial inflammatory disease affecting the ocular surface. Tear hyperosmolarity in dry eye contributes to inflammation and cell damage. Recent research efforts on dry eye have been directed toward biomarker discovery for diagnosis, response to treatment, and disease mechanisms. This study employed a spontaneously immortalized normal human conjunctival cell line, IOBA-NHC, as a model to investigate hyperosmotic stress-induced changes of metabolites and proteins. Global and targeted metabonomic analyses as well as proteomic analysis were performed on IOBA-NHC cells incubated in serum-free media at 280 (control), 380, and 480 mOsm for 24 h. Twenty-one metabolites and seventy-six iTRAQ-identified proteins showed significant changes under at least one hyperosmotic stress treatment as compared with controls. SWATH-based proteomic analysis further confirmed the involvement of inflammatory pathways such as prostaglandin 2 synthesis in IOBA-NHC cells under hyperosmotic stress. This study is the first to identify glycerophosphocholine synthesis and O-linked β-N-acetylglucosamine glycosylation as key activated pathways in ocular surface cells under hyperosmotic stress. These findings extend the current knowledge in metabolite markers of dry eye and provide potential therapeutic targets for its treatment.
No related grants have been discovered for Lei Zhou.