Granzyme B-Induced Neurotoxicity Is Mediated via Activation of PAR-1 Receptor and Kv1.3 Channel

Increasing evidence supports a critical role of T cells in neurodegeneration associated with acute and subacute brain inflammatory disorders. Granzyme B (GrB), released by activated T cells, is a cytotoxic proteinase which may induce perforin-independent neurotoxicity. Here, we studied the mechanism of perforin-independent GrB toxicity by treating primary cultured human neuronal cells with recombinant GrB. GrBactivated the protease-activated receptor (PAR)-1 receptor on the neuronal cell surface leading to decreased intracellular cyclic AMP levels. This was followed by increased expression and translocation of the voltage gated potassium channel, Kv1.3 to the neuronal cell membrane. Similar expression of Kv1.3 was also seen in neurons of the cerebral cortex adjacent to active inflammatory lesions in patients with multiple sclerosis. Kv1.3 expression was followed by activation of Notch-1 resulting in neurotoxicity. Blocking PAR-1, Kv1.3 or Notch-1 activation using specific pharmacological inhibitors or siRNAs prevented GrB-induced neurotoxicity. Furthermore, clofazimine protected against GrB-induced neurotoxicity in rat hippocampus, in vivo. These observations indicate that GrB released from T cells induced neurotoxicity by interacting with the membrane bound Gi-coupled PAR-1 receptor and subsequently activated Kv1.3 and Notch-1. These pathways provide novel targets to treat T cell-mediated neuroinflammatory disorders. Kv1.3 is of particular interest since it is expressed on the cell surface, only under pathological circumstances, and early in the cascade of events making it an attractive therapeutic target.     

Form Variations in the Rotifer Brachionus calyciflorus Pallas from a Perennial Impoundment in India

All three classical forms of Brachionus calyciflorus Pallas viz., calyciflorus, dorcas and amphiceros were recognised in the impoundment. The form amphiceros was most abundant, and its occurrence is attributed to the presence of Asplanchna brightwelli in the tank. Euglena viridis appears to be the preferred food of B. calyciflorus in this impoundment.     

Molecular docking analysis of flupenthixol and desmethylastemizole with the apoptotic regulator proteins CFLAR and TRAF2 linked to lung carcinoma

It is known that molecular changes in apoptotic genes due to mutation may cause disruption of apoptotic pathway resulting in an abrupt increase in cell proliferation. Therefore, it is of interest to identify compounds that could potentially replenish the changes in the apoptotic pathway, resulted from mutation. The gene network analysis using the Network Analyzer Plugin of Cytoscape (3.5.1) shows CFLAR and TRAF2 as influential genes in the apoptotic pathway. Mutation in these genes brings loss in apoptotic property of a cell and thus increases the cell proliferating activity. Thus, data on the molecular docking analysis of four natural compounds from Ottelia alismoides (L.) Pers with the two target proteins were reported. Flupenthixol and desmethylastemizole was found to be two efficient ligand molecules based on ligand-target interaction. In stereochemical quality assessment, the Ramachandran plot analysis of receptors indicates the better stereochemical characteristics for receptor-ligand interaction.     

Subchronic Arsenic Exposure Through Drinking Water Alters Lipid Profile and Electrolyte Status in Rats

Arsenic is a groundwater pollutant and can cause various cardiovascular disorders in the exposed population. The aim of the present study was to assess whether subchronic arsenic exposure through drinking water can induce vascular dysfunction associated with alteration in plasma electrolytes and lipid profile. Rats were exposed to arsenic as 25, 50, and 100 ppm of sodium arsenite through drinking water for 90 consecutive days. On the 91st day, rats were sacrificed and blood was collected. Lipid profile and the levels of electrolytes (sodium, potassium, and chloride) were assessed in plasma. Arsenic reduced high-density lipoprotein cholesterol (HDL-C) and HDL-C/LDL-C ratio, but increased the levels of triglycerides, total cholesterol, low-density lipoprotein cholesterol (LDL-C), and electrolytes. The results suggest that the arsenic-mediated dyslipidemia and electrolyte retention could be important mechanisms in the arsenic-induced vascular disorder.     

Tumor Necrosis Factor,but Not Neutrophils,Alters the Metabolic Profile in Acute Experimental Arthritis

Metabolic alterations are associated with arthritis apart from obesity. However, it is still unclear which is the underlying process behind these metabolic changes. Here, we investigate the role of tumor necrosis factor (TNF) in this process in an acute model of antigen-induced arthritis (AIA). Immunized male BALB/c mice received an intra-articular injection of PBS (control) or methylated bovine serum albumin (mBSA) into their knees, and were also pre-treated with different drugs: Etanercept, an anti-TNF drug, DF2156A, a CXCR1/2 receptor antagonist, or a monoclonal antibody RB6-8C5 to deplete neutrophils. Local challenge with mBSA evoked an acute neutrophil influx into the knee joint, and enhanced the joint nociception, along with a transient systemic metabolic alteration (higher levels of glucose and lipids, and altered adipocytokines). Pre-treatment with the conventional biological Etanercept, an inhibitor of TNF action, ameliorated the nociception and the acute joint inflammation dominated by neutrophils, and markedly improved many of the altered systemic metabolites (glucose and lipids), adipocytokines and PTX3. However, the lessening of metabolic changes was not due to diminished accumulation of neutrophils in the joint by Etanercept. Reduction of neutrophil recruitment by pre-treating AIA mice with DF2156A, or even the depletion of these cells by using RB6-8C5 reduced all of the inflammatory parameters and hypernociception developed after AIA challenge, but could not prevent the metabolic changes. Therefore, the induction of joint inflammation provoked acute metabolic alterations which were involved with TNF. We suggest that the role of TNF in arthritis-associated metabolic changes is not due to local neutrophils, which are the major cells present in this model, but rather due to cytokines.     

Amino acid interaction preferences in proteins

Understanding the key factors that influence the interaction preferences of amino acids in the folding of proteins have remained a challenge. Here we present a knowledge‐based approach for determining the effective interactions between amino acids based on amino acid type, their secondary structure, and the contact based environment that they find themselves in the native state structure as measured by their number of neighbors. We find that the optimal information is approximately encoded in a 60 × 60 matrix describing the 20 types of amino acids in three distinct secondary structures (helix, beta strand, and loop). We carry out a clustering scheme to understand the similarity between these interactions and to elucidate a nonredundant set. We demonstrate that the inferred energy parameters can be used for assessing the fit of a given sequence into a putative native state structure.