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Hijacking intrinsic resistance in Mycobacterium abscessus with small molecule prodrugs

ABSTRACT: This proposal aims to develop narrow-spectrum prodrug-activated protein synthesis inhibitors to treat Mycobacterium abscessus (Mabs) infections. It builds on a recent discovery in our program, which elucidated a unique mechanism for prodrug activation of florfenicol amine (FFA) by hijacking the protective methods Mabs uses to block antibiotic action. Non-tuberculous mycobacteria (NTM) are emerging pathogens with high intrinsic drug resistance. Mabs is the most pathogenic refractory NTM member,1-3 and infections with this pathogen are associated with especially poor clinical outcomes, similar to XDR-TB (extensively drug-resistant tuberculosis)1. Florfenicol (FF) is a broad-spectrum analog of chloramphenicol (CAM), is orally bioavailable, safely used in agriculture as it lacks some of the pharmacological liabilities of CAM, and it mitigates plasmid-borne resistance by blocking the primary-hydroxy site of inactivation. FFA is the primary metabolite found in many host species after FF administration. Through routine MIC screening of synthetic intermediates, we discovered that FFA on its own had appreciable WhiB7 transcription factor-dependent MIC activity against Mabs. Further studies demonstrated that in Mabs FFA acts as a prodrug that is acylated into the active form (FFac) within Mabs by Eis2, a Mabs specific acetyltransferase. eis2 is located in the whiB7 resistome, which results in a feed-forward mechanism of action between FFA, eis2, and whiB7, ultimately increasing the conversion of FFA to FFac, resulting in increased sensitivity. FFA was found to be highly synergistic with other protein synthesis inhibitors and resistance to FFA by inactivation of whiB7 or eis2 results in increased sensitivity to aminoglycosides and macrolides. Since eis2 is only present in Mabs and other closely related species, FFA has a narrow spectrum of activity and avoids the potential for mitochondrial cytotoxicity. Preliminary pharmacological studies demonstrate FFA is noncytotoxic and orally bioavailable.

ORGANISM(S): Mycobacteroides abscessus Mycobacteroides abscessus ATCC 19977

PROVIDER: GSE273574 | GEO | 2025/07/01

REPOSITORIES: GEO

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Project description:Maternal metabolic disorders such as obesity and diabetes are detrimental factors that compromise fertility and the success rates of medically assisted procreation (MAP) procedures. During metabolic stress, adipose tissue is more likely to release free fatty acids (FFA) in the serum resulting in an increase of FFA levels not only in blood, but also in follicular fluid (FF). In humans, high concentrations of palmitic acid (PA) and stearic acid (SA) reduced granulosa cell survival and were associated with poor cumulus-oocyte complex (COC) morphology. Obesity and high levels of circulating FFA were also causatively linked to hampered insulin sensitivity in cells and compensatory hyperinsulinemia. To provide a global picture of the principal upstream signaling pathways and genomic mechanisms involved in this metabolic context, human granulosa-like tumor cells (KGN) were treated with a combination of PA, oleic acid (OA), and SA at the higher physiological concentrations found in the follicular fluid of women with a higher body mass index (BMI) (≥ 30.0 kg/m2). We also tested a high concentration of insulin alone and in combination with high concentrations of fatty acids. Transcription analysis by RNA-seq with a cut off for fold change of 1.5 and p-value 0.05 resulted in thousands of differentially expressed genes for each treatment. Using analysis software such as Ingenuity Pathway Analysis (IPA), we were able to establish that high concentrations of FFA affected the expression of genes mainly related to glucose and insulin homoeostasis, fatty acid metabolism, as well as steroidogenesis and granulosa cell differentiation processes. The combination of insulin and high concentrations of FFA affected signaling pathways related to apoptosis, inflammation, and oxidative stress. Taken together, our results provided new information on the mechanisms that might be involved in human granulosa cells exposed to high concentrations of FFA and insulin in the contexts of metabolism disorders.

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Hijacking intrinsic resistance in Mycobacterium abscessus with small molecule prodrugs

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