Redox index of Cys-thiol residues of serum apolipoprotein E and its diagnostic potential.
Biosci Rep 2021;
41:229292. [PMID:
34286848 PMCID:
PMC8350432 DOI:
10.1042/bsr20211060]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 07/14/2021] [Accepted: 07/21/2021] [Indexed: 12/04/2022] Open
Abstract
Background: The redox modulation of Cys-thiol participates in various pathophysiological processes. We explored the proper index for estimating the redox status of Cys-thiol of serum apolipoprotein E (apoE), named “redox-IDX-apoE,” which is necessary to understand the redox biology of age-related diseases.
Methods: The fractions of the reduced form (red-), reversible oxidized form (roxi-), and irreversibly oxidized form (oxi-) apoE in serum, obtained from the patients with no apparent disease (controls, n=192) and with atherosclerosis and type 2 diabetes (patients, n=16), were measured by a band-shift assay using a maleimide compound. Redox-IDX-apoE candidates were determined by calculating the values of these fractions and the total apoE concentration.
Results: Cys number of apoE significantly increased for the ratio of roxi-apoE to total-apoE (roxi/total) (E2/E3>E3/E3>E3/E4) but decreased for the ratios of red-apoE to roxi-apoE (red/roxi) and [red-apoE + oxi-apoE] to roxi-apoE ([red + oxi]/roxi) (E2/E3<E3/E3<E3/E4). Considering the subjects with apoE3/E3, these ratios were independent of age and sex. Roxi/total showed negative correlations with serum triglyceride (TG) and HbA1c levels, while both red/roxi and [red + oxi]/roxi showed significant positive correlations with them. However, red/roxi and [red + oxi]/roxi in patients were significantly lower than those in controls, although serum TG and HbA1c levels in the patients were significantly higher than those in controls.
Conclusion: The redox status of serum apoE-Cys-thiol is closely involved in the metabolism of TG-rich lipoproteins and glucose. The appropriate use of redox-IDX-apoE could be helpful in the diagnosis and prognosis of age-related diseases and in understanding the underlying mechanisms.
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