Mohammed Haris Siddiqui

Cypermethrin induces astrocyte damage: Role of aberrant Ca 2+ , ROS, JNK, P38, matrix metalloproteinase 2 and migration related reelin protein

Cypermethrin is a synthetic type II pyrethroid, derived from a natural pyrethrin of the chrysanthemum plant. Cypermethrin-mediated neurotoxicity is well studied; however, relatively less is known of its effect on astrocyte development and migration. Astrocytes are the major components of blood brain barrier (BBB), and astrocyte damage along with BBB dysfunction impair the tight junction (TJ) proteins resulting in altered cell migration and neurodegeneration. Here, we studied the mechanism of cypermethin mediated rat astrocyte damage and BBB disruption, and determined any change in expression of proteins associated with cell migration. Through MTT assay we found that cypermethrin reduced viability of cultured rat astrocytes. Immunolabelling with astrocyte marker, glial fibrillary acidic protein, revealed alteration in astrocyte morphology. The astrocytes demonstrated an enhanced release of intracellular Ca(++) and ROS, and up-regulation in p-JNK and p-P38 levels in a time-dependent manner. Cypermethrin disrupted the BBB (in vivo) in developing rats and attenuated the expression of the extracellular matrix molecule (ECM) and claudin-5 in cultured astrocytes. We further observed an augmentation in the levels of matrix metalloproteinase 2 (MMP2), known to modulate cellular migration and disrupt the developmental ECM and BBB. We observed an increase in the levels of reelin, involved in cell migration, in cultured rat astrocytes. The reelin receptor, α3β1integrin, and a mammalian cytosolic protein Disabled1 (Dab1) were also up-regulated. Overall, our study demonstrates that cypermethrin induces astrocyte injury via modulation in Ca(++), ROS, JNK and P38 pathways, which may alter MMP expression and reelin dependent astrocyte migration during brain development.

Evaluation and physiological correlation of plasma proteomic fingerprints for deltamethrin-induced hepatotoxicity in Wistar rats

AIMS Uprising reports towards deltamethrin (DLM)-induced toxicity in non-target species including mammals have raised a worldwide concern. Moreover, in the absence of any identified marker, the prediction of DLM elicited early toxic manifestations in non-targets remains elusive. MAIN METHODS Comprehensive approach of proteome profiling along with conventional toxico-physiological correlation analysis was performed to classify novel protein based markers in the plasma of DLM exposed Wistar rats. Animals were exposed orally to DLM (low dose: 2.56mg/kg b.wt. and high dose: 5.12mg/kg b.wt.) up to seven consecutive days. KEY FINDINGS The UPLC-MS/MS analysis revealed a dose-dependent dissemination of DLM and its primary metabolite (3-Phenoxy benzoic acid) in rat plasma. Through 2-DE-MS/MS plasma profiling and subsequent verification at the transcriptional level, we found that 6 liver emanated acute phase proteins (Apolipoprotein-AIV, Apolipoprotein E, Haptoglobin, Hemopexin, Vitamin D Binding protein, and Fibrinogen gamma chain) were significantly (p<0.05) modulated in DLM treated groups in a dose-dependent manner. Accordingly, DLM exposure resulted in adverse effects on body growth (body weight & relative organ weight), serum profile, liver function and histology, inflammatory changes (enhanced TNF-ɑ, TGF-β and IL6 level), and oxidative stress. Moreover, these toxic manifestations were suppressed upon N-acetyl cysteine (NAC) supplementation in DLM treated animals. Thus, DLM-induced inflammatory response and subsequent oxidative injury to liver grounds the altered expression of identified acute phase proteins. SIGNIFICANCE In conclusion, we proposed these six liver emanated plasma proteins as novel candidate markers to assess the early DLM-induced hepatotoxicity in non-target species with a minimal invasive mean.

Deltamethrin induced RIPK3-mediated caspase-independent non-apoptotic cell death in rat primary hepatocytes

Deltamethrin (DLM), a synthetic pyrethroid insecticide, is used all over the world for indoor and field pest management. In the present study, we investigated the elicited pathogenesis of DLM-induced hepatotoxicity in rat primary hepatocytes. DLM-induced cell death was accompanied with increased ROS generation, decreased mitochondrial membrane potential and G2/M arrest. Pre-treatment with N-acetyl cysteine/butylated hydroxyanisole/IM54 could partly rescue hepatocytes suggesting that ROS might play a role in DLM-induced toxicity. Interestingly, DLM treatment resulted in a caspase-independent but non-apoptotic cell death. Pre-treatment with pan-caspase inhibitor (ZVAD-FMK) could not rescue hepatocytes. Unaltered caspase-3 activity and absence of cleaved caspase-3 also corroborated our findings. Further, LDH release and Transmission electron microscopy (TEM) analysis demonstrated that DLM incites membrane disintegrity and necrotic damage. Immunochemical staining revealed an increased expression of inflammatory markers (TNFα, NFκB, iNOS, COX-2) following DLM treatment. Moreover, the enhanced RIPK3 expression in DLM treated groups and prominent rescue from cell death by GSK-872 indicated that DLM exposure could induce programmed necrosis in hepatocytes. The present study demonstrates that DLM could induce hepatotoxicity via non-apoptotic mode of cell death.

Molecular docking and dynamic simulation evaluation of Rohinitib - Cantharidin based novel HSF1 inhibitors for cancer therapy.

Recent developments in the target based cancer therapies have identified HSF1 as a novel non oncogenic drug target. The present study delineates the design and molecular docking evaluation of Rohinitib (RHT) - Cantharidin (CLA) based novel HSF1 inhibitors for target-based cancer therapy. Here, we exploited the pharmacophoric features of both the parent ligands for the design of novel hybrid HSF1 inhibitors. The RHT-CLA ligands were designed and characterized for ADME/Tox features, interaction with HSF1 DNA binding domain and their pharmacophoric features essential for interaction. From the results, amino acid residues Ala17, Phe61, His63, Asn65, Ser68, Arg71 and Gln72 were found crucial for HSF1 interaction with the Heat shock elements (HSE). The hybrid ligands had better affinity towards the HSF1 DNA binding domain, in comparison to RHT or CLA and interacted with most of the active site residues. Additionally, the HSF1-ligand complex had a reduced affinity towards HSE in comparison to native HSF1. Based on the results, ligand RC15 and RC17 were non carcinogenic, non mutagenic, completely biodegradable under aerobic conditions, had better affinity for HSF1 (1.132 and 1.129 folds increase respectively) and diminished the interaction of HSF1 with HSE (1.203 and 1.239 folds decrease respectively). The simulation analysis also suggested that the ligands formed a stable complex with HSF1, restraining the movement of active site residues. In conclusion, RHT-CLA hybrid ligands can be used as a potential inhibitor of HSF1 for non-oncogene target based cancer therapy.

A Rapid Method for the Quantitative Determination of 34 Pesticides in Nonalcoholic Carbonated Beverages Using Liquid–Liquid Extraction Coupled to Dispersive Solid-Phase Cleanup Followed by Gas Chromatography with Tandem Mass Spectrometry

An economical, rapid, and sensitive multiresidue method using liquid-liquid extraction (LLE) coupled with dispersive SPE (dSPE) cleanup was developed for the quantitative determination of 34 multiclass multiresidue (MCMR) pesticides (14 organochlorines, eight organophosphates, 10 synthetic pyrethroids, and two herbicides) in nonalcoholic carbonated beverages (cola, orange, lemon-lime, and citra) using GC with tandem MS. The procedure mainly involved LLE by dichloromethane and dSPE cleanup in the presence of magnesium sulfate, primary secondary amine, and C18. The RSD of the developed method was found to be less than 14%. The LOD and LOQ values for all the analyzed pesticides were found in the ranges of 0.001-0.027 μg/L and 0.004-0.088 μg/L, respectively. The LOQ levels of the pesticides analyzed were found to be well below the recommended limit by the European Union (0.1 μg/L in water). The mean recoveries of pesticides in different nonalcoholic carbonated beverages (cola, orange, lemon-lime, and citra) were found to be in the range of 79-111%, with RSDs less than 11%. The validation data prove that the method can be acceptable to regulatory agencies for the routine analysis of MCMR pesticides in nonalcoholic carbonated beverages.

Multidrug ABC transporter Cdr1 of Candida albicans harbors specific and overlapping binding sites for human steroid hormones transport

The present study examines the kinetics of steroids efflux mediated by the Candida drug resistance protein 1 (Cdr1p) and evaluates their interaction with the protein. We exploited our in-house mutant library for targeting the 252 residues forming the twelve transmembrane helices (TMHs) of Cdr1p. The screening revealed 65 and 58 residues critical for β-estradiol and corticosterone transport, respectively. Notably, up to 83% critical residues for corticosterone face the lipid interface compared to 54% for β-estradiol. Molecular docking identified a possible peripheral corticosterone-binding site made of 8/14 critical/non-critical residues between TMHs 3, 4 and 6. β-estradiol transport was severely hampered by alanine replacements of Cdr1p core residues involving TMHs 2, 5 and 8, in a binding site made of 10/14 critical residues mainly shared with rhodamine 6G with which it competes. By contrast, TMH11 was poorly impacted, although being part of the core domain. Finally, we observed the presence of several contiguous stretches of 3-5 critical residues in TMHs 2, 5 and 10 that points to a rotation motion of these helices during the substrate transport cycle. The selective structural arrangement of the steroid-binding pockets in the core region and at the lipid-TMD interface, which was never reported before, together with the possible rotation of some TMHs may be the structural basis of the drug-transport mechanism achieved by these type II ABC transporters.

In-silico designing of a potent analogue against HIV-1 Nef protein and protease by predicting its interaction network with host cell proteins.

Background: HIV-1 has numerous proteins encoded within its genome, which acquaints it with the required arsenal to establish a favorable host cell environment suitable for viral replication and pathogenesis. Among these proteins, one protein that is indispensable and ambiguous is the Nef protein. Aim: Interaction of Nef protein with different host-cell protein was predicted and subsequently the down regulation of cluster of differentiation 4 (CD4) was targeted through designing of inhibitors of Nef protein for either preventing or if not at least delaying pathogenesis. Materials and Methods: The interaction network of Nef protein with host-cell proteins were predicted by PIMRider. Analogue of Lopinavir were prepared and evaluated considering all factors affecting the drug stability and toxicity. Finally Docking simulation were performed using an Auto-Dock Tool 4.0. Results: In the interaction network of Nef protein with different host-cell proteins it was found out that 22 host cell proteins are involved in the interaction and execution of different types of functions in host cell but these functions are altered with the interaction with the Nef protein. After extensive and controlled in silico analysis it has been observed that the analogue LOPI1 binds to Nef protein (2NEF) at CD4 interacting site residues giving minimum binding energy of –7.68 Kcal/mole, low Ki value of 2.34 μM, maximum number of hydrogen bonds (8), good absorption, distribution, metabolism and excretion properties, and less toxicity in comparison with the standard Lopinavir against HIV1 protease (1HPV). Conclusion: The newly designed analogue (LOPI1) is showing significant in silico interaction with Nef protein and protease and can be taken forward as a potent drug lead, which may finally emerge out to be even better than the standard Lopinavir.