Structure-Activity Relationships in Nucleotide Oligomerization Domain-1 (Nod1)-Agonistic γ-Glutamyl-diaminopimelic Acid Derivatives

N-acyl-γ-glutamyl-diaminopimelic acid is a prototype ligand for Nod1. We report a detailed SAR of C12-γ-D-Glu-DAP. Analogues with glutaric or γ-aminobutyric acid replacing the glutamic acid show greatly attenuated Nod1-agonistic activity. Substitution of the meso-diaminopimelic (DAP) acid component with monoaminopimelic acid, L- or D-lysine, or cadaverine also results in reduced activity. The free amine on DAP is crucial. However, the N-acyl group on the D-glutamyl residue can be substituted with N-alkyl groups with full preservation of activity. The free carboxylates on the DAP and Glu components can also be esterified, resulting in more lipophilic, but active analogues. Transcriptomal profiling showed a dominant upregulation of IL-19, IL-20, IL-22, and IL-24, which may explain the pronounced Th2-polarizing activity of these compounds, and also implicate cell signaling mediated by TREM-1. These results may explain the hitherto unknown mechanism of synergy between Nod1- and TLR-agonists, and are likely to be useful in designing vaccine adjuvants

Structure-Activity Relationships in Toll-like Receptor 2-Agonists Leading to Simplified Monoacyl Lipopeptides

Toll-like receptor 2-agonistic lipopeptides typified by S-[2,3-bis(palmitoyloxy)-(2RS)-propyl]-R-cysteinyl-S-serine (PAM2CS) compounds are potential vaccine adjuvants. In continuation of previously reported structure-activity relationships on this chemotype, we have determined that at least one acyl group of optimal length (C16) and an appropriately orientated ester carbonyl group is essential for TLR2-agonistic activity. The spacing between one of the palmitoyl ester carbonyl and the thioether is crucial to allow for an important H-bond, which observed in the crystal structure of the lipopeptide:TLR2 complex; consequently, activity is lost in homologated compounds. Penicillamine-derived analogues are also inactive, likely due to unfavorable steric interactions with the carbonyl of Ser 12 in TLR2. The thioether in this chemotype can be replaced with a selenoether. Importantly, the thioglycerol motif can be dispensed with altogether, and can be replaced with a thioethanol bridge. These results have led to a structurally simpler, synthetically more accessible, and water-soluble analogue possessing strong TLR2-agonistic activities in human blood

Microwave induced eco-friendly solvent-free Biginelli reaction catalyzed by calcium chloride^†

2018-2020An efficient one-pot rapid synthesis of 4-aryl-3, 4-dihydropyrimidine-2-(1H)-ones/thiones (DHPMs) involving CaCl2 catalyzed Biginelli three-component condensation under microwave irradiation in a solvent-free condition is reported

Identification of Drugs Targeting Multiple Viral and Human Proteins Using Computational Analysis for Repurposing Against COVID-19

The SARS-CoV2 is a highly contagious pathogen that causes a respiratory disease named COVID-19. The COVID-19 was declared a pandemic by the WHO on 11th March 2020. It has affected about 5.38 million people globally (identified cases as on 24th May 2020), with an average lethality of ~3%. Unfortunately, there is no standard cure for the disease, although some drugs are under clinical trial. Thus, there is an urgent need of drugs for the treatment of COVID-19. The molecularly targeted therapies have proven their utility in various diseases such as HIV, SARS, and HCV. Therefore, a lot of efforts are being directed towards the identification of molecules that can be helpful in the management of COVID-19. In the current studies, we have used state of the art bioinformatics techniques to screen the FDA approved drugs against thirteen SARS-CoV2 proteins in order to identify drugs for quick repurposing. The strategy was to identify potential drugs that can target multiple viral proteins simultaneously. Our strategy originates from the fact that individual viral proteins play specific role in multiple aspects of viral lifecycle such as attachment, entry, replication, morphogenesis and egress and targeting them simultaneously will have better inhibitory effect. Additionally, we analyzed if the identified molecules can also affect the host proteins whose expression is differentially modulated during SARS-CoV2 infection. The differentially expressed genes (DEGs) were identified using analysis of NCBI-GEO data (GEO-ID: GSE-147507). A pathway and protein-protein interaction network analysis of the identified DEGs led to the identification of network hubs that may play important roles in SARS-CoV2 infection. Therefore, targeting such genes may also be a beneficial strategy to curb disease manifestation. We have identified 29 molecules that can bind to various SARS-CoV2 and human host proteins. We hope that this study will help researchers in the identification and repurposing of multipotent drugs, simultaneously targeting the several viral and host proteins, for the treatment of COVID-19.</p