No abstract

We have previously described new pathways of vitamin D3 activation by CYP11A1 to produce a variety of metabolites including 20(OH)D3 and 20,23(OH) 2 D3. These can be further hydroxylated by CYP27B1 to produce their C1α-hydroxyderivatives. CYP11A1 similarly initiates the metabolism of lumisterol (L3) through sequential hydroxylation of the side chain to produce 20(OH)L3, 22(OH)L3, 20,22(OH) 2 L3 and 24(OH)L3. CYP11A1 also acts on 7dehydrocholesterol (7DHC) producing 22(OH)7DHC, 20,22(OH) 2 7DHC and 7dehydropregnenolone (7DHP) which can be converted to the D3 and L3 configurations following exposure to UVB. These CYP11A1-derived compounds are produced in vivo and are biologically

Microbes form surface adherent community structures called biofilms and these biofilms play a critical role in infection. Biofilms impart antibiotic resistance and sometimes become recalcitrant to host immune system. It has reported by the National Institutes of Health that more than 80% of the bacterial infections caused by biofilms formation. Such kind of infection is also prevalent in biomedical devices which becomes a source of infection.The treatment of biofilm mediated infections is a big challenge that requires more sensitive and effective antibiofilm strategies for their removal. Nanoparticles targeted antibiofilm therapy has gained tremendous impetus in last decade due to their unique features. These are wonder particles having a wide spectrum biological applications and among these there antibiofilm activity is significantly useful. These particles are reactive entities and can easily infiltrate into the matrix which acts as a barrier for many antibiotics. Biomedical surfaces are also nano-functionalized by coating, impregnation or embedding nanomaterials to prevent biofilm formation. The study of interaction between nanoparticles and biofilm can provide us more insights about the mechanism of biofilm regulation. In this review article several classes of NPs effective against a broad range of microbial biofilms, both in vivo and in vitro are described. The application of nanoparticles against biofilm will help to fight resistant infections and will share its role in improving human health in the future.

Mangifera indica inflorescence aqueous extract was utilized for production of green AgNPs. Synthesized AgNPs were characterized by UV-vis spectrophotometry, XRD, TEM, FESEM and particles size analyzer. AgNPs showed minimum inhibitory concentrations (MICs) of 8 μg ml-1 and 16 μg ml-1 for Gram negative (K. pneumoniae, P. aeruginosa and E. coli) and Gram positive (S. mutans and S. aureus) strains, respectively which was relatively quite low compared to chemically synthesized silver nanoparticles. AgNPs inhibited 80% and 75% biofilms of E. coli and S. mutans respectively as observed quantitatively by crystal violet assay. Qualitative biofilm inhibition was observed using SEM and CLSM. AgNPs adsorbed catheter also resisted the growth of biofilm on its surface displaying its possible future applications. AgNPs interaction with bacteria lead to bacterial membrane damage as observed by SEM and TEM. The membrane damage was confirmed by detecting leakage of proteins and reducing sugars from treated bacterial cells. AgNPs generated ROS on interaction with bacterial cells and this ROS production can be one of the possible reasons for their action. AgNPs exhibited no toxic effect on the cell viability of HeLa cell line.

The interactions of derivatives of lumisterol (L3) and vitamin D3 (D3) with liver X receptors (LXRs) were investigated. Molecular docking using crystal structures of the ligand binding domains (LBDs) of LXRα and β revealed high docking scores for L3 and D3 hydroxymetabolites, similar to those of the natural ligands, predicting good binding to the receptor. RNA sequencing of murine dermal fibroblasts stimulated with D3-hydroxyderivatives revealed LXR as the second nuclear receptor pathway for several D3-hydroxyderivatives, including 1,25(OH)2D3. This was validated by their induction of genes downstream of LXR. L3 and D3-derivatives activated an LXR-response element (LXRE)-driven reporter in CHO cells and human keratinocytes, and by enhanced expression of LXR target genes. L3 and D3 derivatives showed high affinity binding to the LBD of the LXRα and β in LanthaScreen TR-FRET LXRα and β coactivator assays. The majority of metabolites functioned as LXRα/β agonists; however, 1,20,25(OH)3D3, 1,25(OH)2D3, 1,20(OH)2D3 and 25(OH)D3 acted as inverse agonists of LXRα, but as agonists of LXRβ. Molecular dynamics simulations for the selected compounds, including 1,25(OH)2D3, 1,20(OH)2D3, 25(OH)D3, 20(OH)D3, 20(OH)L3 and 20,22(OH)2L3, showed different but overlapping interactions with LXRs. Identification of D3 and L3 derivatives as ligands for LXRs suggests a new mechanism of action for these compounds.

No abstract

Vitamin D deficiency significantly correlates with the severity of SARS-COV-2 infection. Molecular docking-based virtual screening studies predict that novel vitamin D and related lumisterol hydroxymetabolites are able to bind to the active sites of two SARS-COV-2 transcription machinery enzymes with high affinity. These enzymes are the main protease (Mpro) and RNA dependent RNA polymerase (RdRP) which play important roles in viral replication and establishing infection. Based on predicted binding affinities and specific interactions, we identified ten D3 and lumisterol analogs as likely binding partners of SARS-CoV-2 Mpro and RdRP and therefore tested their ability to inhibit these enzymes. Activity measurements demonstrated that 25(OH)L3, 24(OH)L3 and 20(OH)7DHC are the most effective of the hydroxymetabolites tested at inhibiting the activity of SARS-CoV-2 Mpro, causing 10-19% inhibition. These same derivatives as well as other hydroxylumisterols and hydroxyvitamin D3 metabolites inhibited RdRP by 50-60%. Thus, inhibition of these enzymes by vitamin D and lumisterol metabolites may provide a novel approach to hindering the SARS-COV-2 infection.

No abstract