Synthesis and characterization of novel 6-fluoro-4-piperidinyl-1,2-benzisoxazole amides and 6-fluoro-chroman-2-carboxamides: antimicrobial studies

Novel derivatives of 6-fluoro-4-piperidinyl-1,2-benzisoxazole amides 4(I-VI) were obtained by the condensation of different acid chlorides with 6-fluoro-3-piperidin-4yl-benzo[d]isoxazole. Also, 6-fluoro-chroman-2-carboxamides 6(I-III) were synthesized by using nebulic acid chloride with different amines in presence of triethylamine as acid scavenger and dichloroethane as solvent. The synthesized compounds were characterized by IR, 1H NMR, and CHN analysis. These molecules were evaluated for their efficacy as antimicrobials in vitro by disc diffusion and microdilution method against pathogenic strains such as Bacillus substilis, Escherichia coli, Pseudomonas fluorescens, Xanthomonas campestris pvs, X. oryzae, Aspergillus niger, A. flavus, Fusarium oxysporum, Trichoderma species, F. monaliforme, and Penicillum species. Compounds 4I, 4IV, 4V, 6I, 6II and 6III showed better inhibitory activity than compared to standard drugs. Among these compounds, 4IV and 6III showed potent inhibitory activity against all the strains and found to be nonstrain dependent. The title compounds represent a novel class of potent antimicrobial agents.     

A scaffoldless technique for self-generation of three-dimensional keratinospheroids on liquid crystal surfaces

We describe a new scaffold-free three-dimensional (3D) cell culture model using cholesteryl ester based lyotropic liquid crystal (LC) substrates. Keratinocytes were deposited randomly on the LC surface where they self-assembled into 3D microtissues or keratinospheroids. The cell density required to form spheroids was optimized. We investigated cell viability using dead/live cell assays. The adhesion characteristics of cells within the microtissues were determined using histological sectioning and immunofluorescence staining. Fourier transform infrared spectroscopy (FTIR) was used to characterize the biochemistry of the keratinospheroids. We found that both cells and microtissues could migrate on the LC surface. The viability study indicated approximately 80% viability of cells in the microtissues up to 20 days of culture. Strong intercellular adhesion was observed in the stratification of the multi-layered microspheroids using field emission-scanning electron microscopy (FE-SEM) and histochemical staining. The cytoskeleton and vinculins of the cells in the microtissues were expressed diffusely, but the microtissues were enriched with lipids and nucleic acids, which indicates close resemblance to the conditions in vivo. The basic 3D culture model based on LC may be used for cell and microtissue migration studies in response to cytochemical treatment.     

Hematological profiles of COVID-19 patients at the Ratlam district,Madhya Pradesh State,India

It is of interest to compare the hematological profile (using Complete blood count) of COVID patients admitted in ICU, private ward, and isolation ward with varying severity. This data will help predict the severity of infection at peripheries and rural areas.  Detailed history and CBC was performed for all the cases. Different ratios and indexes such as systemic inflammatory index (SII), Neutrophil lymphocyte ratio (NLR), platelet lymphocyte ratio (PLR) were assessed. A total of 862 cases with a mean age of 49.9 ±17.4 years were enrolled. Hemoglobin level, lymphocyte (count per liter and percentage) were significantly lower in patients admitted in ICU as compared to patients admitted in the isolation ward and private ward (p <0.05). However, TLC, neutrophils, platelet count were higher in patients admitted to ICU (p <0.05). The Various ratios such as SII, NLR, and PLR showed significantly higher value in cases admitted in ICU (p <0.05). The TLC, neutrophil count, neutrophil percentage, SII, NLR, and PLR were significant predictors of severe disease (admission in ICU) with high diagnostic accuracy. We show that complete blood count method is a simple, readily available, rapid, and inexpensive tool that can be utilized for diagnosis and can predicting the severity of COVID 19 where RTPCR or trained staff is not available. Thus, NLR (%), SII, PLR, and TLC can predict severe illness with high accuracy.     

A Nano-MgO and Ionic Liquid-Catalyzed ‘Green’ Synthesis Protocol for the Development of Adamantyl-Imidazolo-Thiadiazoles as Anti-Tuberculosis Agents Targeting Sterol 14α-Demethylase (CYP51)

In this work, we describe the ‘green’ synthesis of novel 6-(adamantan-1-yl)-2-substituted-imidazo[2,1-b][1,3,4]thiadiazoles (AITs) by ring formation reactions using 1-(adamantan-1-yl)-2-bromoethanone and 5-alkyl/aryl-2-amino1,3,4-thiadiazoles on a nano material base in ionic liquid media. Given the established activity of imidazothiadiazoles against M. tuberculosis, we next examined the anti-TB activity of AITs against the H₃₇Rv strain using Alamar blue assay. Among the tested compounds 6-(adamantan-1-yl)-2-(4-methoxyphenyl)imidazo[2,1-b][1,3,4]thiadiazole (3f) showed potent inhibitory activity towards M. tuberculosis with an MIC value of 8.5 μM. The inhibitory effect of this molecule against M. tuberculosis was comparable to the standard drugs such as Pyrazinamide, Streptomycin, and Ciprofloxacin drugs. Mechanistically, an in silico analysis predicted sterol 14α-demethylase (CYP51) as the likely target and experimental activity of 3f in this system corroborated the in silico target prediction. In summary, we herein report the synthesis and biological evaluation of novel AITs against M. tuberculosis that likely target CYP51 to induce their antimycobacterial activity.     

Anti-Tumor Activity of a Novel HS-Mimetic-Vascular Endothelial Growth Factor Binding Small Molecule

The angiogenic process is controlled by variety of factors of which the vascular endothelial growth factor (VEGF) pathway plays a major role. A series of heparan sulfate mimetic small molecules targeting VEGF/VEGFR pathway has been synthesized. Among them, compound 8 (2-butyl-5-chloro-3-(4-nitro-benzyl)-3H-imidazole-4-carbaldehyde) was identified as a significant binding molecule for the heparin-binding domain of VEGF, determined by high-throughput-surface plasmon resonance assay. The data predicted strong binding of compound 8 with VEGF which may prevent the binding of VEGF to its receptor. We compared the structure of compound 8 with heparan sulfate (HS), which have in common the functional ionic groups such as sulfate, nitro and carbaldehyde that can be located in similar positions of the disaccharide structure of HS. Molecular docking studies predicted that compound 8 binds at the heparin binding domain of VEGF through strong hydrogen bonding with Lys-30 and Gln-20 amino acid residues, and consistent with the prediction, compound 8 inhibited binding of VEGF to immobilized heparin. In vitro studies showed that compound 8 inhibits the VEGF-induced proliferation migration and tube formation of mouse vascular endothelial cells, and finally the invasion of a murine osteosarcoma cell line (LM8G7) which secrets high levels of VEGF. In vivo, these effects produce significant decrease of tumor burden in an experimental model of liver metastasis. Collectively, these data indicate that compound 8 may prevent tumor growth through a direct effect on tumor cell proliferation and by inhibition of endothelial cell migration and angiogenesis mediated by VEGF. In conclusion, compound 8 may normalize the tumor vasculature and microenvironment in tumors probably by inhibiting the binding of VEGF to its receptor.     

Roles of glycosaminoglycans and glycanmimetics in tumor progression and metastasis

Various tumor cells exhibit structural alterations in the sulfated modifications to glycosaminoglycans (GAGs). The altered expression of chondroitin sulfate (CS) and heparan sulfate (HS) on the surfaces of tumor cells is known to play a key role in malignant transformation and tumor metastasis. The receptor molecule for the CS chains containing E-disaccharide units (CS-E) expressed on Lewis lung carcinoma (LLC) cells was recently revealed to be Receptor for Advanced Glycation End-products (RAGE). RAGE is also involved in the development of various pathological conditions including aging, infection, pulmonary fibrosis, diabetes, and Alzheimer’s disease, by binding to a wide range of ligands. RAGE binds strongly not only to CS-E, but also to HS-expressing LLC cells. Recombinant RAGE bound CS-E and HS with high affinity. Furthermore, in a mouse model, the colonization of the lungs by LLC cells was inhibited by intravenously injected CS-E, an anti-CS-E antibody, or an anti-RAGE antibody. These findings demonstrated that RAGE is at least one of the critical receptors for CS and HS chains expressed on the tumor cell surface and is involved in experimental lung metastasis, and also that CS/HS and RAGE are potential molecular targets for the treatment of pulmonary metastasis. We, hence, reviewed these findings and also several chemically synthesized small GAGmimetics that exhibit potent anti-metastatic and/or anti-tumor activities.     

Patterns of Biofilm Succession on a Sheltered Rocky Shore in Hong Kong

Successional patterns are dependent on the nature of the substratum, water flow, concentrations of organics as well as the availability of bacteria, algal spores and invertebrate larvae in the coastal environment. Bacteria play an especially important role in biofilm formation as they are generally the earliest colonizers. In the present study, both winter and summer biofilm succession patterns were examined on glass coverslips inverted on experimental racks attached at two tidal levels on a sheltered shore in Hong Kong. In the succession, bacteria were followed by diatoms and cyanobacteria. Encrusting algae appeared in the late stages of the experiment (day 80 in summer and day 60 in winter). Colonization by bacteria was much slower in summer and their density remained low throughout the experimental period. The first appearance of diatoms and cyanobacteria, however, was more rapid in the summer. Bacteria and diatoms on the low-shore surfaces also had a faster succession rate than on the high-shore surfaces, suggesting that desiccation/aerial temperature are the causal factors for such differences.     

Antagonist-mediated down-regulation of toll-like receptors increases the prevalence of human papillomavirus infection in systemic lupus erythematosus

IntroductionPrevalence of an abnormal Papanicolaou smear was significantly increased in lupus patients in cross-sectional studies, associated with a higher prevalence of high-risk human papillomavirus (HPV) infection. The nucleic acid-specific Toll-like receptors (TLRs) locate at the endolysosomal compartments and trigger the induction of cytokines for the innate immune response. This study evaluated whether abnormal host innate immune response in lupus patients may enhance HPV persistence.MethodsProtein levels of TLRs 3, 7, 8 and 9 in cervical epithelial cells of lupus patients and controls with or without HPV infection were assessed using flow cytometry. Characteristics associated with the differential expression of TLRs in systemic lupus erythematosus (SLE) were elucidated. The effect and interferon-stimulated genes (ISGs) (ISG15 and Mx-1) gene expressions were then measured in oncogenic HeLa (HPV18), CaSki (HPV) and C33A (HPV negative) cell lines using flow cytometry and quantitative real-time PCR. Ex vivo productions of cytokines and interferon-gamma (IFN-γ) upon TLR ligands stimulations were subsequently measured using cytometric bead array and ELISA.ResultsFor subjects with HPV infection, levels of TLR3 and TLR7 were significantly lower in lupus patients compared with controls. Significantly decreased TLRs 7, 8 and 9 levels were observed in HPV-negative SLE compared to healthy controls. For SLE with and without HPV infection, TLR7 and 9 levels were significantly lower in infected SLE than those in HPV-negative patients. Independent explanatory variables associated with down-regulation of TLR7 level included HPV infection and a higher cumulative dose of prednisolone; while a higher cumulative dose of hydroxychloroquine and HPV infection were associated with down-regulation of TLR9 level. In cervical cell lines, TLRs 3, 7, 8, 9 protein levels and antiviral ISG15 and Mx-1 gene expressions were inhibited in two oncogenic HPV types. Functional data showed that the induction of pro-inflammatory cytokines by TLR ligands (R837, ssRNA and ODN2395) was greatly impaired in CaSki and HeLa than C33A cells.ConclusionsIn conclusion, prednisolone and TLR antagonist (hydroxychloroquine) may down-regulate protein levels of TLR7 and TLR9 in lupus patients, thereby decreasing the innate immune response against HPV infection. Upon infection, HPV further down-regulate TLR7 and 9 levels for viral persistence. Furthermore, reduction of nucleic acid-sensing TLRs 7, 8 and 9 in carcinogenic HPVs ensures that the expression of inducible pro-inflammatory cytokines is minimized to prevent the expression of antiviral ISGs (ISG15 and Mx-1) on a biologically relevant antiviral response.