Dwivedi, V. P. | bioRxiv Science

bioRxiv2026

All-trans retinoic acid recalibrates macrophage transcriptional responses to drug-resistant Mycobacterium tuberculosis through strain-specific immunometabolic reprogramming

Tuberculosis (TB) caused by Mycobacterium tuberculosis (M.tb) remains the leading infectious cause of death worldwide, with multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains presenting an escalating therapeutic crisis. All-trans retinoic acid (ATRA), an active vitamin A metabolite with established immunomodulatory properties, has emerged as a candidate host-directed therapy, yet its genome-wide transcriptional effects on macrophage across strains of differing drug-resistance profiles remain uncharacterized. We performed RNA sequencing of murine peritoneal macrophages infected with drug-susceptible H37Rv, MDR-2261, or XDR-MCY M.tb strains, with and without ATRA treatment, validated by RT-PCR and flow cytometry. All three strains activated a conserved pro-inflammatory program dominated by Nos2, Il1b, and Acod1 induction with progressive suppression of host translational and mitochondrial machinery. XDR-MCY uniquely induced Ifnb1/IFN-{beta}, suppressed Prdx1 and Gpx4, the latter shared with MDR-2261 and showed selective downregulation of MHC-II processing genes, suggesting a multilayered immune evasion strategy. ATRA activated canonical retinoid signaling across all infection states and consistently induced Arg1-mediated resolution signaling, with Nos2 suppression observed in H37Rv- and MDR-infected macrophages. ATRA selectively restored Epas1/HIF-2 in H37Rv- and MDR-infected macrophages without disrupting the HIF-1-driven antimicrobial program or itaconate biosynthesis. ATRA responsiveness progressively attenuated with drug resistance, with XDR-MCY-infected macrophages largely refractory to transcriptional reprogramming. These findings provide a transcriptional rationale for evaluating ATRA as a host-directed adjunct in drug-resistant TB and identify Gpx4 suppression in drug-resistant strains and XDR-specific Ifnb1 induction as vulnerabilities necessitating further investigation.

microbiology↗

bioRxiv2022

Novel Peptide Inhibitor of Human Tumor Necrosis Factor-α has Antiarthritic Activity

The inhibition of tumor necrosis factor- (TNF) trimer formation renders it inactive for binding to its receptors thus mitigating the vicious cycle of inflammation. We designed a peptide (PIYLGGVFQ) that simulates a sequence strand of human TNF monomer using a series of in silico methods, such as active site finding (Acsite), protein-protein interaction (PPI), docking studies (GOLD and Modeller) followed by molecular dynamics (MD) simulation studies. The MD studies confirmed the intermolecular interaction of the peptide with the TNF. Fluorescence-activated cell sorting (FACS) and fluorescence microscopy revealed that the peptide effectively inhibited the binding of TNF to the cell surface receptors. The cell culture assays showed that the peptide significantly inhibited the TNF-mediated cell death. In addition, the nuclear translocation of the nuclear factor kappa B (NF{kappa}B) was significantly suppressed in the peptide-treated A549 cells as observed in immunofluorescence and gel mobility-shift assays. Furthermore, peptide protected against joint damage in collagen-induced arthritis (CIA) mouse model as revealed in the microfocal-CT scans. In conclusion, this TNF antagonist would be useful for the prevention and repair of inflammatory bone destruction and subsequent loss in the mouse model of CIA as well as human rheumatoid arthritis (RA) patients. This calls upon further clinical investigation to utilize its potential effect as an anti-arthritic drug.

immunology↗