IMPA1

Bisphenol A (BPA) is an endocrine disruptor of potential reproductive toxicities. Increasingly research elucidated that BPA exposure to the environment would change the epigenetic modifications of transcriptome, but the mechanism by which BPA affects m6A methylation in interfering with female reproductive health remains uncertain. Therefore, this study preliminarily proposed and tested the hypothesis that BPA exposure alters the m6A modification level in transcripts in female ovarian granulosa cells. After BPA was exposed to granulosa cells for 24 h, RNA methylation related regulatory genes (such as METTL3, METTL14, ALKBH5, FTO) and the global m6A levels showed significant differences. Next, we applied MERIP-seq analysis to obtain information on the genome-wide m6A modification changes and identified 1595 differentially methylated mRNA transcripts, and 50 differentially methylated lncRNA transcripts. Further joint analysis of gene common expression showed that 33 genes were hypermethylated and up-regulated, 71 were hypermethylated and down-regulated, 49 were hypomethylated and up-regulated, and 20 were hypomethylated and down-regulated. Enriched Gene Ontology (GO) and biological pathway analysis revealed that these unique genes were mainly enriched in lipid metabolism, cell proliferation, and apoptosis related pathways. Six of these genes (mRNAs IMPA1, MCOLN1, DCTN3, BRCA2, and lncRNAs MALAT1, XIST) were validated using RT-qPCR and IGV software. Through comprehensive analysis of epitranscriptome and protein-protein interaction (PPI) data, lncRNAs MALAT1 and XIST are expected to serve as new markers for BPA interfering with the female reproductive system. In brief, these data show a novel and necessary connection between the damage of BPA exposure on female ovarian granulosa cells and RNA methylation modification.

Metallo-β-lactamases (MBLs) represent one of the main causes of carbapenem resistance in the order Enterobacterales. To combat MBL-producing carbapenem-resistant Enterobacterales, the development of MBL inhibitors can restore carbapenem efficacy for such resistant bacteria. Microbial natural products are a promising source of attractive seed compounds for the development of antimicrobial agents. Here, we report that hydroxyhexylitaconic acids (HHIAs) produced by a member of the genus Aspergillus can suppress carbapenem resistance conferred by MBLs, particularly IMP (imipenemase)-type MBLs. HHIAs were found to be competitive inhibitors with micromolar orders of magnitude against IMP-1 and showed weak inhibitory activity toward VIM-2, while no inhibitory activity against NDM-1 was observed despite the high dosage. The elongated methylene chains of HHIAs seem to play a crucial role in exerting inhibitory activity because itaconic acid, a structural analog without long methylene chains, did not show inhibitory activity against IMP-1. The addition of HHIAs restored meropenem and imipenem efficacy to satisfactory clinical levels against IMP-type MBL-producing Escherichia coli and Klebsiella pneumoniae clinical isolates. Unlike EDTA and Aspergillomarasmine A, HHIAs did not cause the loss of zinc ions from the active site, resulting in the structural instability of MBLs. X-ray crystallography and in silico docking simulation analyses revealed that two neighboring carboxylates of HHIAs coordinated with two zinc ions in the active sites of VIM-2 and IMP-1, which formed a key interaction observed in MBL inhibitors. Our results indicated that HHIAs are promising for initiating the design of potent inhibitors of IMP-type MBLs.IMPORTANCEThe number and type of metallo-β-lactamase (MΒL) are increasing over time. Carbapenem resistance conferred by MΒL is a significant threat to our antibiotic regimen, and the development of MΒL inhibitors is urgently required to restore carbapenem efficacy. Microbial natural products have served as important sources for developing antimicrobial agents targeting pathogenic bacteria since the discovery of antibiotics in the mid-20th century. MΒL inhibitors derived from microbial natural products are still rare compared to those derived from chemical compound libraries. Hydroxyhexylitaconic acids (HHIAs) produced by members of the genus Aspergillus have potent inhibitory activity against clinically relevant IMP-type MBL. HHIAs may be good lead compounds for the development of MBL inhibitors applicable for controlling carbapenem resistance in IMP-type MBL-producing Enterobacterales.

Lithium (Li) is widely used as a mood stabilizer to treat bipolar affective disorder. However, the molecular targets of Li that underpin its therapeutic effect remain unresolved. Inositol monophosphatase (IMPA1) is an enzyme involved in phosphatidylinositol 4,5-bisphosphate (PIP₂) resynthesis after PLC signaling. In vitro, Li inhibits IMPA1, but the relevance of this inhibition within neural cells remains unknown. Here, we report that treatment with therapeutic concentrations of Li reduces receptor-activated calcium release from intracellular stores and delays PIP₂ resynthesis. These effects of Li are abrogated in IMPA1 deleted cells. We also observed that in human forebrain cortical neurons, treatment with Li reduced neuronal excitability and calcium signals. After Li treatment of human cortical neurons, transcriptome analyses revealed down-regulation of signaling by glutamate, a key excitatory neurotransmitter in the human brain. Collectively, our findings suggest that inhibition of IMPA1 by Li reduces receptor-activated PLC signaling and neuronal excitability.