Acetyl-proteome profiling revealed the role of lysine acetylation in erythromycin resistance of Staphylococcus aureus.

Background: Staphylococcus aureus (S. aureus), a prevalent human pathogen known for its propensity to cause severe infections, has exhibited a growing resistance to antibiotics. Lysine acetylation (Kac) is a dynamic and reversible protein post-translational modification (PTM), played important roles in various physiological functions. Recent studies have shed light on the involvement of Kac modification in bacterial antibiotic resistance. However, the precise relationship between Kac modification and antibiotic resistance in S. aureus remains inadequately comprehended. Methods: We compared the differential expression of acetylated proteins between erythromycin-resistant (Ery-R) and erythromycin-susceptible (Ery-S) strains of S. aureus by 4D label-free quantitative proteomics technology. Additionally, we employed motif analysis, functional annotation and PPI network to investigate the acetylome landscape and heterogeneity of S. aureus. Furthermore, polysome profiling experiments were performed to assess the translational status of ribosome. Results: 6791 Kac sites were identified on 1808 proteins in S. aureus, among which 1907 sites in 483 proteins were quantified. A total of 548 Kac sites on 316 acetylated proteins were differentially expressed by erythromycin pressure. The differentially acetylated proteins were primarily enriched in ribosome assembly, glycolysis and lysine biosynthesis. Bioinformatic analyses implied that Kac modification of ribosomal proteins may play an important role in erythromycin resistance of S. aureus. Western bolt and polysome profiling experiments indicated that the increased Kac levels of ribosomal proteins in the resistant strain may partially offset the inhibitory effect of erythromycin on ribosome function. Conclusions: Our findings confirm that Kac modification is related to erythromycin resistance in S. aureus and emphasize the potential roles of ribosomal proteins. These results expand our current knowledge of antibiotic resistance mechanisms, potentially guiding future research on PTM-mediated antibiotic resistance.

Mettl3-m6A-YTHDF1 axis promotion of mitochondrial dysfunction in metabolic dysfunction-associated steatotic liver disease.

BACKGROUND: N6-methyladenosine (m6A) mRNA modification and mitochondrial function hold paramount importance in the advancement of metabolic dysfunction-associated steatotic liver disease (MASLD). AIM: The aim of this study was to elucidate the impact of m6A on hepatic mitochondrial dysfunction and provide a novel perspective for a more comprehensive understanding of the pathogenesis of MASLD. METHODS: High-throughput screening methods were used to identify the underlying transcriptome and proteome changes in MASLD model mice. Western blotting, blue native gel electrophoresis (BNGE), dot blot, and Seahorse analyses were conducted to identify and validate the underlying regulatory mechanisms of m6A on mitochondria. RESULTS: In vivo, abnormal m6A modification in MASLD was attributed to the upregulation of methyltransferase like 3 (Mettl3) and the downregulation of YTH N6-methyladenosine RNA binding protein 1 (YTHDF1) induced by high-fat foods. In vitro, knockdown of Mettl3 inhibited hepatic oxidative phosphorylation (OXPHOS) and the mitochondrial respiratory chain (MRC), while overexpression of Mettl3 promoted these processes. However, knockout of the reader protein YTHDF1, which plays a crucial role in the m6A modification process, counteracted the effect of Mettl3 and suppressed mitochondrial OXPHOS. CONCLUSIONS: In MASLD, damage to the MRC may be regulated by the Mettl3-m6A-YTHDF1 axis, particularly by the role of YTHDF1. Modulation of the Mettl3-m6A-YTHDF1 axis has the potential to improve mitochondrial function, alleviate MASLD symptoms, and decrease the likelihood of disease progression.

Electron Spin Broken-Symmetry of Fe-Co Diatomic Pairs to Promote Kinetics of Bifunctional Oxygen Electrocatalysis for Zinc-Air Batteries.

Designing bifunctional catalysts to reduce the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) reaction barriers while accelerating the reaction kinetics is perceived to be a promising strategy to improve the performance of Zinc-air batteries. Unsymmetric configuration in single-atom catalysts has attracted attention due to its unique advantages in regulating electron orbitals. In this work, a seesaw effect in unsymmetric Fe-Co bimetallic monoatomic configurations is proposed, which can effectively improve the OER/ORR bifunctional activity of the catalyst. Compared with the symmetrical model of Fe-Co, a strong charge polarization between Co and Fe atoms in the unsymmetric model is detected, in whom the spin-down electrons around Co atoms are much higher than those spin-up electrons. The seesaw effect occurred between Co atoms and Fe atoms, resulting in a negative shift of the d-band center, which means that the adsorption of oxygen intermediates is weakened and more conducive to their dissociation. The optimized reaction kinetics of the catalyst leads to excellent performance in ZABs, with a peak power density of 215 mW cm-2 and stable cycling for >1300 h and >4000 cycles. Flexible Zinc-air batteries have also gained excellent performance to demonstrate their potential in the field of flexible wearables.

The lncRNA MEG3/miRNA-21/P38MAPK axis inhibits coxsackievirus 3 replication in acute viral myocarditis.

Evidence is emerging on the roles of long noncoding RNAs (lncRNAs) as regulatory factors in a variety of viral infection processes, but the mechanisms underlying their functions in coxsackievirus group B type3 (CVB3)-induced acute viral myocarditis have not been explicitly delineated. We previously demonstrated that CVB3 infection decreases miRNA-21 expression; however, lncRNAs that regulate the miRNA-21-dependent CVB3 disease process have yet to be identified. To evaluate lncRNAs upstream of miRNA-21, differentially expressed lncRNAs in CVB3-infected mouse hearts were identified by microarray analysis and lncRNA/miRNA-21 interactions were predicted bioinformatically. MEG3 was identified as a candidate miRNA-21-interacting lncRNA upregulated in CVB3-infected mouse hearts. MEG3 expression was verified to be upregulated in HeLa cells 48 h post CVB3 infection and to act as a competitive endogenous RNA of miRNA-21. MEG3 knockdown resulted in the upregulation of miRNA-21, which inhibited CVB3 replication by attenuating P38-MAPK signaling in vitro and in vivo. Knockdown of MEG3 expression before CVB3 infection inhibited viral replication in mouse hearts and alleviated cardiac injury, which improved survival. Furthermore, the knockdown of CREB5, which was predicted bioinformatically to function upstream of MEG3, was demonstrated to decrease MEG3 expression and CVB3 viral replication. This study identifies the function of the lncRNA MEG3/miRNA-21/P38 MAPK axis in the process of CVB3 replication, for which CREB5 could serve as an upstream modulator.