Molecular docking studies of benzimidazopyrimidine and coumarin substituted benzimidazopyrimidine derivatives: As potential human Aurora A kinase inhibitors

Protein kinases are important drug targets in human cancers, inflammation and metabolic diseases. Docking studies was performed for all the benzimidazopyrimidine and coumarin substituted benzimidazopyridimine derivatives with human Aurora A kinase target (3FDN) employing flexible ligand docking approach by using AutoDock 4.2. All the compounds were found to have minimum binding energy ranging from -6.26 to -9.29 kJ/mol. Among the molecules tested for docking study, 10-(6-Bromo-2-oxo- 2H-chromen-4-ylmethyl)-2-isopropyl-10H-benzo[4,5]imidazo[1,2-a]pyrimidin-4-one (2k) showed minimum binding energy (-9.29 kJ/mol) with ligand efficiency of -0.31. All the ligands were docked deeply within the binding pocket region of 3FDN showing hydrogen bonds with Ala 213 and Asn 261. The docking study results showed that these derivatives are excellent inhibitor of human Aurora A kinase target; and also all these docked compounds have good inhibition constant, vdW + Hbond + desolv energy with best RMSD value.     

Molecular docking of 1H-pyrazole derivatives to receptor tyrosine kinase and protein kinase for screening potential inhibitors

Tyrosine kinase receptor and protein kinases drawn much attention for the scientific fraternity in drug discovery due to its important role in different cancer, cardiovascular diseases and other hyper-proliferative disorders. Docking studies of pyrazole derivatives with tyrosine kinase and different serine/threonine protein kinases were employed by using flexible ligand docking approach of AutoDock 4.2. Among the molecules tested for docking study, 2-(4-chlorophenyl)-5-(3-(4-chlorophenyl)-5-methyl-1- phenyl-1H-pyrazol-4-yl)-1,3,4-thiadiazole (1b), 2-(4-methoxyphenyl)-5-(3-(4-methoxyphenyl)-5-methyl-1-phenyl-1H-pyrazol-4-yl)- 1,3,4-thiadiazole (1d) and 2-(4-chlorophenyl)-5-(3-(4-chlorophenyl)-5-methyl-1-phenyl-1H-pyrazol-4-yl)-1,3,4-thiadiazole (2b) revealed minimum binding energy of -10.09, -8.57 and -10.35 kJ/mol with VEGFR-2 (2QU5), Aurora A (2W1G) and CDK2 (2VTO) protein targets, respectively. These proteins are representatives of plausible models of interactions with different anticancer agents. All the ligands were docked deeply within the binding pocket region of all the three proteins, showing reasonable hydrogen bonds. The docking study results showed that these pyrazole derivatives are potential inhibitor of all the three protein targets; and also all these docked compounds have good inhibition constant, vdW + Hbond + desolv energy with best RMSD value.     

MTHFR C677T Predisposes to POAG but Not to PACG in a North Indian Population: A Case Control Study

Hyperhomocysteinemia induced by the C677T genetic variant in MTHFR (methylenetetrahydrofolate reductase) has been implicated in neuronal cell death of retinal ganglion cells (RGC), which is a characteristic feature of glaucoma. However, association of MTHFR C677T with glaucoma has been controversial because of inconsistent results across association studies. Association between MTHFR C677T and glaucoma has not been reported in Indian population. Therefore, with a focus on neurodegenerative death of RGC in glaucoma, the current study aimed to investigate association of MTHFR C677T with Primary Open Angle Glaucoma (POAG) and Primary Angle Closure Glaucoma (PACG) in a North Indian population. A total of 404 participants (231 patients and 173 controls) were included in this study. Genotyping was performed by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism. A few random samples were also tested by direct sequencing. Genotypic and allelic distributions of the POAG and PACG cohorts were compared to that of controls by chi-square test and odds ratios were reported with 95% confidence intervals. Genotypic and allelic distributions between POAG cases and controls were significantly different (p = 0.03 and p = 0.01 respectively). Unlike POAG, we did not find significant difference in the genotypic and allelic distributions of C677T between PACG cases and controls (p>0.05). We also observed a higher proportion of TT associated POAG in females than that in males. However, this is a preliminary indication of gender specific risk of C677T that needs to be replicated in a larger cohort of males and females. The present investigation on MTHFR C677T and glaucoma reveals that the TT genotype and T allele of this polymorphism are significant risk factors for POAG but not for PACG in North Indian population. Ours is the first report demonstrating association of MTHFR C677T with POAG but not PACG in individuals from North India.     

Impaired Expression of Type I and Type II Interferon Receptors in HCV-Associated Chronic Liver Disease and Liver Cirrhosis

Purpose

Chronic Hepatitis C Virus (HCV)-infected patients with liver cirrhosis (LC) respond poorly to interferon-alpha (IFN-α) and ribavirin (RBV) combination therapy, but the reason for this is unclear. We previously reported that HCV-infection induces endoplasmic reticulum (ER) stress and autophagy response that selectively down regulates the type I IFN-α receptor-1 (IFNAR1) and RBV transporters (CNT1 and ENT1), leading to IFN-α/RBV resistance. The goal of this study is to verify whether an increase in ER stress and autophagy response is also associated with the reduced expression of IFNAR1 and RBV transporters in chronic HCV-infected patients.

Methods

Primary human hepatocytes (PHH) were infected with cell culture grown HCV particles (JFH-ΔV3-Rluc). HCV replication was confirmed by the detection of viral RNA by RT-qPCR and HCV-core protein by Western blotting. The ER stress and autophagy response and expression of IFN receptors and RBV transporters in HCV infected PHH and liver tissues derived from patients were measured by Western blotting.

Result

HCV infection of PHH showed impaired expression of IFNAR1, IFNγR1 (Type II IFN receptor) and RBV transporters but not IL10Rβ (Type III IFN-λ receptor). ER stress markers (BiP, IRE1α and peIF2α) and autophagy response (LC3II, Beclin 1 and ATG5) were induced in HCV infected chronic liver disease (CLD) and LC patients. Liver biopsies (CLD) show a 50% reduced expression of IFNAR1 and RBV transporters. Furthermore, the expression of IFNAR1 and RBV transporters was impaired in almost all LC patients.

Conclusion

HCV infection induces ER stress and autophagy response in infected PHH and chronically infected liver tissues. The expression of IFNAR1, IFNγR1 and RBV transporters were significantly impaired in CLD and cirrhotic livers. Our study provides a potential explanation for the reduced response rate of IFN-α and RBV combination therapy in HCV infected patients with liver cirrhosis.     

Synthesis and biological evaluation of [4-(2-phenylethenesulfonylmethyl)phenyl]-quinazolin-4-yl-amines as orally active anti-cancer agents

A new series of [4-(2-phenylethenesulfonylmethyl)phenyl]quinazolin-4-yl-amines was prepared and tested for its in vitro cytotoxic activity against a panel of 12 human cancer cell lines. Compounds 9, 15, 24 and 31 showed good in vitro activity and were further tested for their in vivo efficacy in the HT-29 human colon adeno carcinoma xenograft model. Compound 9 exhibited promising activity in this model. Dose-response studies for this compound against HT-29 human colon adeno carcinoma xenografts at 100, 200 and 400mg/kg doses were performed.     

Inhibition of collagen glycation and crosslinking in vitro by methanolic extracts of Finger millet (Eleusine coracana) and Kodo millet (Paspalum scrobiculatum)

The present investigation was carried out to study the effects of methanolic extracts of Finger millet (Eleusine coracana) and Kodo millet (Paspalum scrobiculatum) on glycation and crosslinking of collagen. Tail tendons obtained from rats weighing 200-225 g were incubated with glucose (50 mM) and 3 mg of extracts of the above millets in methanol under physiological conditions of temperature and pH for 10 days. Early glycation was estimated by phenol-sulfuric acid method and the crosslinking was assessed by pepsin digestion, cyanogen bromide peptide map and viscosity measurements. Tendon collagen incubated with glucose (50 mM) showed 65% solubility on pepsin treatment; poor resolution of bands in the cyanogen bromide peptide map, and intrinsic viscosity of 0.84 dl/g. The collagen incubated with Finger millet and Kodo millet extracts inhibited glycation; 89% and 92% solubility in pepsin; good resolution of bands in the cyanogen bromide peptide map and intrinsic viscosity of 0.46 and 0.58 dl/g respectively. The study implicates the potential usefulness of the above millets in protection against glycation and crosslinking of collagen.     

COVID‐19 lockdown frees wildlife to roam but increases poaching threats in Nepal

To contain transmission of COVID‐19, lockdowns or strict restrictions of people''s mobility outside their residences were instituted in a majority of countries worldwide, including Nepal, where the first phase of nationwide lockdown was observed from 24 March to 21 July 2020. This sudden halt in human outdoor activities brought positive and negative impacts on forests and wildlife. We undertook a study to learn the impact of the COVID‐19 lockdown on wildlife and forests in the protected areas (PAs) of Nepal. Between July and September 2020, data on illegal activities recorded by the staff of PAs and also those reported by media were collected and analyzed. Key informant interviews (KII) were done with the park officers and security personnel by virtual communication (telephone, messenger app, and video call) to collect detailed information and for corroboration. The collected data were categorized into four groups: (a) wildlife killed, (b) wildlife injured, (c) arrest incidents related to forest crime, and (d) arrest incidents related to wildlife crime. Data from the fiscal year 2019–2020 were analyzed, comparing before lockdown and after. Among 20 PAs investigated during the lockdown, the study found substantial increases in wildlife death in two PAs, Banke National Park, and Bardia National Park. Similarly, Chitwan National Park (CNP) and Shivapuri Nagarjun National Park (SNNP) witnessed a rise in wildlife poaching. CNP and SNNP are located close to densely populated cities and also have human settlements in their peripheries. Wildlife was sighted freely roaming inside PAs during the lockdown, presumably because the absence of visitors and human activities during the lockdown decreased disturbance. Thus, the wildlife was enjoying the freedom of movement on the one hand, and on the other hand was threatened by poachers, many of whom were laid off from other activities and were taking advantage of the lapse in security.     

Strategies to target SARS-CoV-2 entry and infection using dual mechanisms of inhibition by acidification inhibitors

Many viruses utilize the host endo-lysosomal network for infection. Tracing the endocytic itinerary of SARS-CoV-2 can provide insights into viral trafficking and aid in designing new therapeutic strategies. Here, we demonstrate that the receptor binding domain (RBD) of SARS-CoV-2 spike protein is internalized via the pH-dependent CLIC/GEEC (CG) endocytic pathway in human gastric-adenocarcinoma (AGS) cells expressing undetectable levels of ACE2. Ectopic expression of ACE2 (AGS-ACE2) results in RBD traffic via both CG and clathrin-mediated endocytosis. Endosomal acidification inhibitors like BafilomycinA1 and NH₄Cl, which inhibit the CG pathway, reduce the uptake of RBD and impede Spike-pseudoviral infection in both AGS and AGS-ACE2 cells. The inhibition by BafilomycinA1 was found to be distinct from Chloroquine which neither affects RBD uptake nor alters endosomal pH, yet attenuates Spike-pseudovirus entry. By screening a subset of FDA-approved inhibitors for functionality similar to BafilomycinA1, we identified Niclosamide as a SARS-CoV-2 entry inhibitor. Further validation using a clinical isolate of SARS-CoV-2 in AGS-ACE2 and Vero cells confirmed its antiviral effect. We propose that Niclosamide, and other drugs which neutralize endosomal pH as well as inhibit the endocytic uptake, could provide broader applicability in subverting infection of viruses entering host cells via a pH-dependent endocytic pathway.