The effect of cysteine oxidation on DJ-1 cytoprotective function in human alveolar type II cells

Abstract

DJ-1 is a multifunctional protein with cytoprotective functions. It is localized in the cytoplasm, nucleus, and mitochondria. The conserved cysteine residue at position 106 (Cys106) within DJ-1 serves as a sensor of redox state and can be oxidized to both the sulfinate (-SO 2 − ) and sulfonate (-SO 3 − ) forms. DJ-1 with Cys106-SO 2 − has cytoprotective activity but high levels of reactive oxygen species can induce its overoxidation to Cys106-SO 3 − . We found increased oxidative stress in alveolar type II (ATII) cells isolated from emphysema patients as determined by 4-HNE expression. DJ-1 with Cys106-SO 3 − was detected in these cells by mass spectrometry analysis. Moreover, ubiquitination of Cys106-SO 3 − DJ-1 was identified, which suggests that this oxidized isoform is targeted for proteasomal destruction. Furthermore, we performed controlled oxidation using H 2 O 2 in A549 cells with DJ-1 knockout generated using CRISPR-Cas9 strategy. Lack of DJ-1 sensitized cells to apoptosis induced by H 2 O 2 as detected using Annexin V and propidium iodide by flow cytometry analysis. This treatment also decreased both mitochondrial DNA amount and mitochondrial ND1 (NADH dehydrogenase 1, subunit 1) gene expression, as well as increased mitochondrial DNA damage. Consistent with the decreased cytoprotective function of overoxidized DJ-1, recombinant Cys106-SO 3 − DJ-1 exhibited a loss of its thermal unfolding transition, mild diminution of secondary structure in CD spectroscopy, and an increase in picosecond–nanosecond timescale dynamics as determined using NMR. Altogether, our data indicate that very high oxidative stress in ATII cells in emphysema patients induces DJ-1 overoxidation to the Cys106-SO 3 − form, leading to increased protein flexibility and loss of its cytoprotective function, which may contribute to this disease pathogenesis.

Chalcone suppresses tumor growth through NOX4-IRE1α sulfonation-RIDD-miR-23b axis

“…Likewise, when parkin is sulfonated, this protein becomes insoluble, probably linked to neuronal dysfunction [ 43 ]. The other protein, Dj-1's sulfonation has been also reported to lose cytoprotective function [ 44 ]. Under severe stress, the Xbp-1 splicing might be overwhelmed/overcome by the parallel RNA decay process [ 45 ].…”

Tea Polyphenols Prevent Sepsis-Induced Lung Injury via Promoting Translocation of DJ-1 to Mitochondria

“…Previous studies have found that DJ-1 protein can be used as a reactive oxygen scavenger and can remove hydrogen peroxide through self-oxidation in vitro cell models ( Taira et al, 2004 ), thus protecting mitochondria from damage. In addition, under the stimulation of oxidative stress, DJ-1 protein can not only prevent the activation of apoptosis pathway by oxidizing its own Cys106 ( Bahmed et al, 2019 ), but also reduce the expression of Bax protein by reducing the transcriptional activity of p53, and then inhibit the apoptotic pathway of Bax-caspases, thus protecting mitochondrial function ( Salah et al, 1995 ). The overexpression of DJ-1 protein can protect cells, enhance the tolerance of cells to toxins, and reduce mitochondrial damage.…”

Stepwise Oxidations Play Key Roles in the Structural and Functional Regulations of DJ-1

“…Since highly reactive Cys46 does not undergo various oxidation [39], it is possible to form a disulfide bond. To investigate whether Cys46 could form a disulfide bond, we examined the electrophoretic mobility of WT and mutant DJ-1s on SDS-PAGE with or without 2-mercaptoethanol (β-ME) ( Fig.…”