Synthesis and biological evaluation of novel cYY analogues targeting Mycobacterium tuberculosis CYP121A1

The rise in multidrug resistant (MDR) cases of tuberculosis (TB) has led to the need for the development of TB drugs with different mechanisms of action. The genome sequence of Mycobacterium tuberculosis (Mtb) revealed twenty different genes coding for cytochrome P450s. CYP121A1 catalyzes a CC crosslinking reaction of dicyclotyrosine (cYY) producing mycocyclosin and current research suggests that either mycocyclosin is essential or the overproduction of cYY is toxic to Mtb. A series of 1,4-dibenzyl-2-imidazol-1-yl-methylpiperazine derivatives were designed and synthesised as cYY mimics. The derivatives substituted in the 4-position of the phenyl rings with halides or alkyl group showed promising antimycobacterial activity (MIC 6.25?μg/mL), with the more lipophilic branched alkyl derivatives displaying optimal binding affinity with CYP121A1 (ⁱPr K_D?=?1.6?μM; ^tBu K_D?=?1.2?μM). Computational studies revealed two possible binding modes within the CYP121A1 active site both of which would effectively block cYY from binding.     

The Effects of Antidepressants “Fluoxetine and Imipramine” on Vascular Abnormalities and Toll Like Receptor-4 Expression in Diabetic and Non-Diabetic Rats Exposed to Chronic Stress

Several studies reveal that diabetes doubles the odds of comorbid depression with evidence of a pro-inflammatory state underlying its vascular complications. Indeed, little information is available about vascular effects of antidepressant drugs in diabetes. Method: We investigated the effect of chronic administration of fluoxetine “FLU” and imipramine “IMIP” on behavioral, metabolic and vascular abnormalities in diabetic and non-diabetic rats exposed to chronic restraint stress (CRS). Results: Both diabetes and CRS induced depressive-like behavior which was more prominent in diabetic/depressed rats; this was reversed by chronic treatment with FLU and IMIP in a comparable manner. Diabetic and non-diabetic rats exposed to CRS exhibited abnormalities in glucose homeostasis, lipid profile and vascular function, manifested by decreased endothelium-dependent relaxation, increased systolic blood pressure and histopathological atherosclerotic changes. Vascular and metabolic dysfunctions were associated with significant increase in aortic expression of TLR-4, and pro-inflammatory cytokines (TNF-α and IL-1ß). FLU ameliorated these metabolic, vascular and inflammatory abnormalities, while IMIP induced either no change or even worsening of some parameters. Conclusion: FLU has favorable effect over IMIP on metabolic, vascular and inflammatory aberrations associated with DM and CRS in Wistar rats, clarifying the preference of FLU over IMIP in management of comorbid depression in diabetic subjects.     

Interplay of LncRNAs NEAT1 and TUG1 in Incidence of Cytokine Storm in Appraisal of COVID-19 Infection

Background: In 2019, the coronavirus pandemic emerged, resulting in the highest mortality and morbidity rate globally. It has a prevailing transmission rate and continues to be a global burden. There is a paucity of data regarding the role of long non-coding RNAs (lncRNAs) in COVID-19. Therefore, the current study aimed to investigate lncRNAs, particularly NEAT1 and TUG1, and their association with IL-6, CCL2, and TNF-α in COVID-19 patients with moderate and severe disease.Methods: The study was conducted on 80 COVID-19 patients (35 with severe and 45 with moderate infection) and 40 control subjects. Complete blood count (CBC), D-dimer assay, serum ferritin, and CRP were assayed. qRT-PCR was used to measure RNAs and lncRNAs.Results: NEAT1 and TUG1 expression levels were higher in COVID-19 patients compared with controls (P<0.001). Furthermore, CCL2, IL-6, and TNF-α expressions were higher in COVID-19 patients compared to controls (P<0.001). CCL2 and IL-6 expression levels were significantly higher in patients with severe compared to those with moderate COVID-19 infection (P<0.001). IL-6 had the highest accuracy in distinguishing COVID-19 patients (AUC=1, P<0.001 at a cutoff of 0.359), followed by TUG1 (AUC=0.999, P<0.001 at a cutoff of 2.28). NEAT1 and TUG1 had significant correlations with the measured cytokines, and based on the multivariate regression analysis, NEAT1 is the independent predictor for survival in COVID-19 patients (P=0.02).Conclusion: In COVID-19 patients, significant overexpression of NEAT1 and TUG1 was observed, consistent with cytokine storm. TUG1 could be an efficient diagnostic biomarker, whereas NEAT1 was an independent predictor for overall survival.     

A novel cytotoxic aryltetraline lactone from Bupleurum marginatum (Apiaceae)

A detailed phytochemical study of the aerial parts of Bupleurum marginatum Wall. ex DC revealed a novel aryltetraline lactone lignan identified as 9-(benzo[d][1,3]dioxol-5-yl)-6,7,8-trimethoxy-3a,4,9,9a-tetrahydronaphtho[2,3-c]furan-1(3H)-one (marginatoxin) along with nine known compounds and characterization of five other compounds either by GLC/MS or LC/MS techniques. Chemical structures of the isolated compounds were unambiguously elucidated by both 1D, 2D NMR and mass spectrometry techniques.The in vitro cytotoxic activity of both methanol and dichloromethane extracts as well as the isolated compounds was assessed in two human cancer cell lines HepG2 and HeLa using the MTT assay. The new aryltetraline lactone lignan exhibited a potent cytotoxic activity with IC₅₀ values of 12.14 and 16.90 μM after 24 h treatment for HepG2 and HeLa cells, respectively.     

Amino acid substitutions of Na,K-ATPase conferring decreased sensitivity to cardenolides in insects compared to mammals

Mutagenesis analyses and a recent crystal structure of the mammalian Na,K-ATPase have identified amino acids which are responsible for high affinity binding of cardenolides (such as ouabain) which at higher doses block the enzyme in the phosphorylated state. Genetic analysis of the Na,K-ATPase of insects adapted to cardenolides in their food plants revealed that some species possess substitutions which confer strongly increased resistance to ouabain in the mammalian enzyme such as the substitution T797A or combined substitutions at positions 111 and 122. To test for the effect of these mutations against the background of insect Na,K-ATPase, we here expressed the ouabain sensitive Na,K-ATPase α-subunit of Drosophila melanogaster together with the β-subunit Nrv3 in baculovirus-infected Sf9 cells and introduced the substitutions N122H, T797A, Q111T-N122H, Q111V-N122H, all of which have been observed in cardenolide-adapted insects. While all constructs showed similar expression levels, ouabain affinity of mutated Na,K-ATPases was reduced compared to the wild-type fly enzyme. Ouabain sensitivity of the ATPase activity in inhibition assays was significantly decreased by all mutations, yet whereas the IC₅₀ for the single mutations of N122H (61.0 μM) or T797A (63.3 μM) was increased roughly 250-fold relative to the wild-type (0.24 μM), the double mutations of Q111V-N122H (IC₅₀ 550 μM) and Q111T-N122H (IC₅₀ 583 μM) proved to be still more effective yielding a 2.250-fold increased resistance to ouabain. The double mutations identified in cardenolide-adapted insects are more effective in reducing ouabain sensitivity of the enzyme than those found naturally in the rat Na,K-ATPase (Q111R-N122D) or in mutagenesis screens of the mammalian enzyme. Obviously, the intense selection pressure on cardenolide exposed insects has resulted in very efficient substitutions that decrease cardenolide sensitivity extremely.     

Development and evaluation of realistic optical cell models for rapid and label‐free cell assay by diffraction imaging

Methods for rapid and label‐free cell assay are highly desired in life science. Single‐shot diffraction imaging presents strong potentials to achieve this goal as evidenced by past experimental results using methods such as polarization diffraction imaging flow cytometry. We present here a platform of methods toward solving these problems and results of optical cell model (OCM) evaluations by calculations and analysis of cross‐polarized diffraction image (p‐DI) pairs. Four types of realistic OCMs have been developed with two prostate cell structures and adjustable refractive index (RI) parameters to investigate the effects of cell morphology and index distribution on calculated p‐DI pairs. Image patterns have been characterized by a gray‐level co‐occurrence matrix (GLCM) algorithm and four GLCM parameters and linear depolarization ratio δ_L have been selected to compare calculated against measured data of prostate cells. Our results show that the irregular shapes of and heterogeneity in RI distributions for organelles play significant roles in the spatial distribution of scattered light by cells in comparison to the average RI values and their differences among the organelles. Discrepancies in GLCM and δ_L parameters between calculated and measured p‐DI data provide useful insight for understanding light scattering by single cells and improving OCM.      

Quantitative structure activity relationships of some pyridine derivatives as corrosion inhibitors of steel in acidic medium

Quantum chemical calculations using the density functional theory (B3LYP/6-31G* DFT) and semi-empirical AM1 methods were performed on ten pyridine derivatives used as corrosion inhibitors for mild steel in acidic medium to determine the relationship between molecular structure and their inhibition efficiencies. Quantum chemical parameters such as total negative charge (TNC) on the molecule, energy of highest occupied molecular orbital (E _HOMO), energy of lowest unoccupied molecular orbital (E _LUMO) and dipole moment (μ) as well as linear solvation energy terms, molecular volume (Vi) and dipolar-polarization (π*) were correlated to corrosion inhibition efficiency of ten pyridine derivatives. A possible correlation between corrosion inhibition efficiencies and structural properties was searched to reduce the number of compounds to be selected for testing from a library of compounds. It was found that theoretical data support the experimental results. The results were used to predict the corrosion inhibition of 24 related pyridine derivatives.     

Role of cationic size in the optical properties of the LiCl crystal surface: theoretical study

The size of the cations (either Ca(2+), Sr(2+), Ga(+), or Au(+)) at the F(A1)-type color centers on the (100) surface of LiCl crystal plays an important role in the optical properties of this surface. In this work, double-well potentials at this surface were investigated using ab initio quantum mechanical methods. Quantum clusters were embedded in simulated Coulomb fields that closely approximate the Madelung fields of the host surface, and the ions that were the nearest neighbors to the F(A1) site were allowed to relax to equilibrium. The calculated Stokes-shifted optical transition bands, optical-optical conversion efficiency, and relaxed excited states of the defect-containing surface, as well as the orientational destruction of the color centers, recording sensitivity, exciton (energy) transfer, and the Glasner-Tompkins empirical relation were all found to be sensitive to the size of the dopant cation.     

The c.242G>A mutation in LRTOMT gene is responsible for a high prevalence of deafness in the Moroccan population

Congenital hearing impairment (HI) affects one in 1,000 newborns and has a genetic cause in 50?% of the cases. Autosomal recessive non-syndromic hearing impairment is responsible for 70–80?% of all hereditary cases of HI. Recently, it has been demonstrated that, mutations of LRTOMT are associated with profound nonsyndromic hearing impairment at the DFNB63 locus. The objective of this study is to evaluate the carrier frequency of c.242G>A mutation in LRTOMT gene and define the contribution of this gene in the etiology of deafness in Moroccan population. We screened 105 unrelated Moroccan families with non-syndromic HI and 120 control individuals for mutation in the exon 8 of the LRTOMT gene, by sequencing and PCR-RFLP. The Homozygous c.242G>A mutation was found in 8.75?% of the families tested and in 4.16?% of control in the heterozygous state. Our results show that after the GJB2 gene mutation in LRTOMT gene is the second cause of congenital hearing impairment in Moroccan patients. This finding should facilitate diagnosis of congenital deafness of the affected subjects in Morocco.