The concept of substrate inhibition to prevent its phosphorylation has potential in drug discovery and is envisioned to treat the autoimmune disorder multiple sclerosis (MS). Glia maturation factor-β (GMF-β) Ser83 phosphorylation by protein kinase A (PKA) is pivotal in the activation of GMF-β-p38MAPK-NFκB biochemical pathway towards proinflammatory response induction in experimental autoimmune encephalomyelitis (EAE). Using structure-based drug design, we identified the small molecule inhibitor 1-H-indazole-4yl methanol (GMFBI.1) that specifically blocked Ser83 phosphorylation site on GMF-β substrate. Using in vitro and in vivo techniques, molecular mechanism of action of GMFBI.1's direct interaction with GMF-β substrate and prevention of its Ser83 phosphorylation was established. GMFBI.1 down regulated p38MAPK phosphorylation and NFκB expression essential for proinflammatory response. Further, GMFBI.1 administration at peak of EAE reversed clinical symptoms, immunopathology, proinflammatory cytokine response and up regulated the anti-inflammatory cytokines. Present strategy of substrate inhibition against the key immunomodulatory target has immense therapeutic potential in MS. Multiple sclerosis is a chronic autoimmune, demyelinating, neurodegenerative disorder of the central nervous system (CNS) affecting 2.5 million people globally 1,2. Despite different disease-modifying therapies adopted to mitigate the inflammatory milieu of MS using different drugs 3-5 , patient's progress from an acute phase to a stage with considerable neurological disabilities. Current therapies modulate disease differently as they target activated T cells, antigen presenting cells or prevent the egress of T cells into brain. Importantly, none of these drugs control molecules that modulate the proinflammatory response at a fundamental level following infiltration of activated T and B lymphocytes 6,7. Activated lymphocytes undergo clonal expansion assisted by the cytokines produced mainly by astrocytes and microglia and glia maturation factor-β (GMF-β) plays an instrumental role in cytokine induction 8,9. Thus, targeting GMF-β could signify a novel approach in controlling the immune response in the brain. Over expression of GMF-β in response to immune challenge up regulates p38MAPK and NFκB expression in astrocytes leading to increased GM-CSF production by astrocytes and microglial generation of TNF-α, IL1-β, IL-6 and IFN-γ, augmenting proinflammatory response 10-12. In the well-established EAE animal model of MS,

The bacterial ribosome is an established target for anti-bacterial therapy since decades. Several inhibitors have already been developed targeting both defined subunits (50S and 30S) of the ribosome. Aminoglycosides and tetracyclines are two classes of antibiotics that bind to the 30S ribosomal subunit. These inhibitors can target multiple active sites on ribosome that have a complex structure. To screen putative inhibitors against 30S subunit of the ribosome, the crystal structures in complex with various known inhibitors were analyzed using pharmacophore modeling approach. Multiple active sites were considered for building energy-based three-dimensional (3D) pharmacophore models. The generated models were validated using enrichment factor on decoy data-set. Virtual screening was performed using the developed 3D pharmacophore models and molecular interaction towards the 30S ribosomal unit was analyzed using the hits obtained for each pharmacophore model. The hits that were common to both streptomycin and paromomycin binding sites were identified. Further, to predict the activity of these hits a robust 2D-QSAR model with good predictive ability was developed using 16 streptomycin analogs. Hence, the developed models were able to identify novel inhibitors that are capable of binding to multiple active sites present on 30S ribosomal subunit.

In the emerging context of gut−brain control of multiple sclerosis (MS), developing therapeutics targeting proinflammatory proteins controlling the gut−brain immunomodulation is welcoming. One such immunomodulator is glia maturation factor-β (GMF-β). GMF-β activation following GMFβ-ser-83 phosphorylation upregulates proinflammatory responses and exacerbates experimental autoimmune encephalomyelitis (EAE). Notably, GMF-β −/− mice exhibited no EAE symptoms. Thus, we identified 1H-indazole-4-yl-methanol (GMFBI.1) inhibitor which blocked GMF-β-ser-83 phosphorylation critical in EAE suppression. To establish gut GMF-β′s role in EAE in the context of gut−brain involvement in neurodegenerative diseases, we altered gut GMFBI.1 bioavailability as an index of EAE suppression. At first, we identified Miglyol 812N as a suitable biocompatible GMFBI.1 carrier compared to other FDA-approved carriers using in silico molecular docking analysis. GMFBI.1 administration in Miglyol 812N enhanced its retention/brain permeability. Subsequently, we administered GMFBI.1-Miglyol 812N by subcutaneous/oral routes at different doses with differential GMFBI.1 bioavailability in gut and brain to assess the role of local GMFBI.1 bioavailability in EAE reversal by a pharmacokinetic approach. Deprival of gut GMFBI.1 bioavailability led to partial EAE suppression despite having sufficient GMFBI.1 in circulation to inhibit brain GMF-β activity. Restoration of gut GMFBI.1 bioavailability led to complete EAE reversal. Molecular pathology behind partial/full EAE reversal was associated with differential GMF-β-Ser-83 phosphorylation/GM-CSF expression levels in enteric glial cells owing to GMFBI.1 bioavailability. In addition, we observed leaky gut reversal, tight junction protein ZO-1 restoration, beneficial gut microbiome repopulation, recovery from gut dysbiosis, and upregulation of Treg cells. GMFBI.1's dual gut/brain targeting of GMF-β has therapeutical/translational potential in controlling autoimmunity in MS.