Obesity-induced protein carbonylation in murine adipose tissue regulates the DNA-binding domain of nuclear zinc finger proteins

Abstract

In obesity-linked insulin resistance, oxidative stress in adipocytes leads to lipid peroxidation and subsequent carbonylation of proteins by diffusible lipid electrophiles. Reduction in oxidative stress attenuates protein carbonylation and insulin resistance, suggesting that lipid modification of proteins may play a role in metabolic disease, but the mechanisms remain incompletely understood. Herein, we show that , diet-induced obesity in mice surprisingly results in preferential carbonylation of nuclear proteins by 4-hydroxy--2,3-nonenal (4-HNE) or 4-hydroxy--2,3-hexenal (4-HHE). Proteomic and structural analyses revealed that residues in or around the sites of zinc coordination of zinc finger proteins, such as those containing the C2H2 or MATRIN, RING, C3H1, or N4-type DNA-binding domains, are particularly susceptible to carbonylation by lipid aldehydes. These observations strongly suggest that carbonylation functionally disrupts protein secondary structure supported by metal coordination. Analysis of one such target, the nuclear protein estrogen-related receptor γ (ERR-γ), showed that ERR-γ is modified by 4-HHE in the obese state. carbonylation decreased the DNA-binding capacity of ERR-γ and correlated with the obesity-linked down-regulation of many key genes promoting mitochondrial bioenergetics. Taken together, these findings reveal a novel mechanistic connection between oxidative stress and metabolic dysfunction arising from carbonylation of nuclear zinc finger proteins, such as the transcriptional regulator ERR-γ.

Adipose oxidative stress and protein carbonylation

“…Proteomic analysis of 4-HNE and 4-HHE protein adducts has revealed a variety of cytoplasmic, mitochondrial, and nuclear targets (6,36,37). Cytoplasmic protein carbonylation has been implicated in the control of insulin signaling as well as glucose and lipid metabolism.…”

“…Strikingly, recent work indicates that carbonylated proteins accumulate preferentially in the nucleus of epididymal adipose depot from mice fed an obesogenic diet (6). This observation is important for two reasons, First, zinc finger proteins and histones were among the most highly enriched for protein car-JBC REVIEWS: Oxidative stress and adipose biology bonylation (6).…”

Modulation of the Liver Protein Carbonylome by the Combined Effect of Marine Omega-3 PUFAs and Grape Polyphenols Supplementation in Rats Fed an Obesogenic High Fat and High Sucrose Diet

“…The explanation behind the combined effect of supplements and their selective behavior on liver proteins can be found if considering how the carbonylation process occurs. Oxidation patterns in protein carbonylation are highly protein specific in terms of the dominant (and others) oxidation mechanism responsible for the induction of this post-translational modification (direct oxidation, reaction with lipid peroxidation products, AGEs), the amino acid which is being carbonylated and the carbonylation motif in each process [7]. Subcellular localization, molecular function of the protein, protein expression and degradation rates, or protein conformation are other critical factors to taking into account.…”

The Impact of Oxidative Stress on Adipose Tissue Energy Balance

“…Increased markers of lipid peroxidation, including thiobarbituric acid reactive substances (TBARS) and 8-epi-prostaglandin-F2α (8-epi-PGF2α) are observed in individuals with higher BMI and waist circumference (Furukawa et al, 2004). Oxidized lipids and proteins preferentially accumulate in visceral depots compared to subcutaneous depots of obese mice (Long et al, 2013;Hauck et al, 2018Hauck et al, , 2019 and humans (Frohnert et al, 2011), suggesting ROS modifications correlate with conditions associated with type 2 diabetes, including central fat accrual.…”

“…Lipid peroxidation products also damage the function of transcription factors that contain zinc-finger motifs, histones, and other nuclear proteins of visceral fat cells isolated from obese mice (Hauck et al, 2018). The lipid peroxidation of transcriptional regulatory proteins presents a consolidated mechanism for retrograde ROS signaling from mitochondria to the nucleus.…”