Biology subjects

Bowling, J.

Publications and source records attributed to Bowling, J..

3 recordsLinked to original sources

bioRxiv2026

Obesity-Driven Lung Lipidome Remodeling Suppresses NK Cell Activation and Antiviral Immunity to Influenza Infection

Obesity is a major risk factor for severe influenza A virus (IAV) infection, however, the innate immune mechanisms underlying this increased vulnerability remain unclear. Here, we identify significant defects in natural killer (NK) cell antiviral responses in mice with diet-induced obesity. In lean mice, NK cells are critical for protection as NK cell depletion during IAV infection led to increased lung viral load, morbidity, and mortality. In contrast, in obese mice NK cell depletion had minimal impact on viral replication or survival. Notably, IAV infection in obese mice recapitulated the phenotype observed in NK cell-depleted lean mice, indicating that obesity is associated with preexisting NK cell dysfunction. Following IAV infection, obese NK cells in the lung were functionally impaired with diminished activation (CD69+), cytokine production (IFN-{gamma}), and cytolytic activity (Granzyme B) accompanied by defects in the mTOR signaling pathway and reduced glycolytic and oxidative metabolism. Bulk and spatial lipidomics revealed obesity and infection-driven remodeling of the lung lipidome. We observed increased triglyceride accumulation, abundance of long-chain free fatty acids, and a shift toward monounsaturated phospholipid species, reshaping the lung microenvironment that coincides with NK cell metabolic dysfunction. Consistent with this lipid-rich environment, obese NK cells sustained high expression of the lipid transporter CD36 post-IAV infection and accumulation of intracellular lipids (LipidTOX+), consistent with mechanisms known to suppress NK cell function. Notably, short-term weight loss (4 weeks) was sufficient to restore NK cell metabolism, antiviral function, and survival following IAV infection. These findings uncover a lipid-associated mechanism regulating NK cell function and show it plays a critical role in defense against infection and that it is dysfunctional in obesity. We suggest that targeting immunometabolism could lead to new antiviral therapies and potentially improve vaccine efficacy, especially in high-risk populations such as obesity. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=101 SRC="FIGDIR/small/710186v1_ufig1.gif" ALT="Figure 1"> View larger version (42K): org.highwire.dtl.DTLVardef@313263org.highwire.dtl.DTLVardef@1e31111org.highwire.dtl.DTLVardef@758ba6org.highwire.dtl.DTLVardef@12372d0_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗

bioRxiv2022

The licorice metabolite enoxolone attenuates Clostridioides difficile pathophysiology by corrupting its metabolic and toxin production networks

Toxins TcdA and TcdB are the main virulence factors of Clostridioides difficile, a leading cause of hospital-acquired diarrhea. We investigated the therapeutic potential of inhibiting the biosynthesis of TcdA and TcdB. Accordingly, screening of structurally diverse phytochemicals with medicinal properties identified 18{beta}-glycyrrhetinic acid (enoxolone) as an inhibitor of TcdA and TcdB biosynthesis. Enoxolone also inhibited sporulation. In a CDI colitis model, enoxolone when combined with vancomycin protected mice from becoming moribund and the combination was more effective than vancomycin alone, a standard of care antibiotic for CDI. While enoxolone alone reduced the in vivo load of toxins, the monotherapy did not protect mice from CDI. Affinity based proteomics identified ATP synthase subunit alpha (AtpA) and adenine deaminase (Ade) as possible molecular targets for enoxolone. Silencing of mRNA for Ade and AtpA also reduced toxin biosynthesis, while molecular interaction analysis showed that enoxolone directly bound to Ade. Ade converts adenine to hypoxanthine as an early step in the purine salvage pathway. Metabolomics revealed enoxolone caused cells to accumulate adenosine and deplete hypoxanthine and ATP. Accordingly, supplementation with hypoxanthine partly restored toxin production. Enoxolone also impacted phosphate metabolism by reducing the amounts of cellular phosphate. Thus, supplementation with triethyl phosphate as a source of phosphate also partly restored toxin production. When hypoxanthine and triethyl phosphate were combined, toxin production was fully restored in the presence of enoxolone. Taken together, studies with enoxolone revealed metabolic pathways that affect C. difficile toxin production and could represent potential anti-virulence drug targets. IMPORTANCEClostridioides difficile, a leading cause of hospital-acquired diarrhea, produces two co-regulated toxins (TcdA and TcdB) that are the focus of most anti-virulence discovery efforts for C. difficile infection (CDI). Exploration of an alternate anti-virulence strategy led to the discovery that the licorice metabolite enoxolone inhibits C. difficile virulence by blocking the cellular biosynthesis of TcdA and TcdB. Blockage of toxin production by enoxolone was associated with multiple effects on cells, including inhibiting adenine deaminase and ATP synthase leading to disruption of purine biosynthesis and phosphate metabolism. In mice infected with C. difficile, the efficacy of enoxolone in combination with vancomycin was superior to vancomycin alone. These findings contribute to establishing toxin biosynthesis inhibition as a newer therapeutic concept for CDI.

microbiology↗

bioRxiv2019

Geldanamycin inhibits Jumonji histone lysine demethylase KDM4 and targets chimeric transcription factor PAX3-FOXO1

Histone lysine demethylases (KDMs) are emerging as therapeutic targets in cancer. Development of potent KDM inhibitors may provide additional options for epigenomics-oriented therapies. Using a Time-Resolved Fluorescence Resonance Energy Transfer (TR-FRET) functional demethylation assay, in combination with a high-content immunofluorescence imaging phenotypic screen, Matrix-Assisted Laser Desorption/Ionization-Fourier Transform Ion Cyclotron Resonance mass spectrometry (MALDI-FTICR MS) and Amplified Luminescent Proximity Homogeneous Assay (ALPHA), we identified geldanamycin, an inhibitor of heat shock protein 90 (Hsp90), as a novel inhibitor of JmjC-domain containing demethylases such as KDM4B. We further found that geldanamycin can destabilize the PAX3-FOXO1 fusion oncoprotein, an Hsp90 client, which is a driver of clinically unfavorable alveolar rhabdomyosarcoma (aRMS). We then hypothesized that dual inhibition of PAX3-FOXO1 and epigenetic modifiers of aRMS would have synergistic antitumor activity. We repurposed the geldanamycin analog 17-DMAG to target aRMS and found that 17-DMAG significantly delays tumor growth, extends survival in xenograft mouse models, and inhibits expression of PAX3-FOXO1 targets and multiple oncogenic pathways including MYC, E2F and NOTCH. In addition, the combination of 17-DMAG with conventional chemotherapy or the bromodomain inhibitor JQ1 significantly enhances therapeutic efficacy. In summary, we have identified geldanamycin and 17-DMAG as dual KDM/Hsp90 inhibitors and 17-DMAG is efficacious against PAX3-FOXO1-driven rhabdomyosarcoma.

cancer biology↗