Induced Stress on Red Blood Cell Promotes Red Blood Cell-Endothelial Adhesion

Cell and Tissue Biology - Besides disease condition, very few stress stimulants were determined to provoke red blood cell (RBC) adhesion to endothelial cells (EC). However, the possible role of...     

Trichosanthes tricuspidata Modulates Oxidative Toxicity in Brain Hippocampus Against Pilocarpine Induced Status Epilepticus in Mice

Epilepsy prevails to be a neurological disorder in anticipation of safer drugs with enhanced anticonvulsant efficacy as presently available drugs fails to offer adequate control of epileptic seizures in about one-third of patients. The objective of this study was to evaluate the effect of Trichosanthes tricuspidata methanolic extract (TTME) against epilepsy mediated oxidative stress in pilocarpine induced mice. Intraperitonial administration of pilocarpine (85 mg/kg) induced seizure in mice was assessed by behavior observations, which is significantly (p < 0.05) reduced by TTME (100 and 200 mg/kg; i.p) in a dose dependant manner, similar to diazepam. Seizure was accompanied by significant increase in lipid peroxidation and the hippocampal nitrite content in pilocarpine group when compared with control. Moreover, the antioxidant enzymes superoxide dismutase, catalase and glutathione levels were decreased in pilocarpine administered groups. TTME administration attenuated oxidative damage as evident by decreased lipid oxidative damage and nitrite–nitrate content and restored the level of enzymatic antioxidant defenses in hippocampus. Involvement of free radicals during epilepsy is further confirmed by histopathological analysis which showed the loss of neuronal cells in hippocampus CA1 and CA3 pyramidal region. Our findings strongly support the hypothesis that TTME has anticonvulsant activity accompanied with the strong antioxidant potential plays a crucial role in reducing the oxidative stress produced by seizure.     

Meta analysis of bioactive compounds,miRNA, siRNA and cell death regulators as sensitizers to doxorubicin induced chemoresistance

Cancer has presented to be the most challenging disease, contributing to one in six mortalities worldwide. The current treatment regimen involves multiple rounds of chemotherapy administration, alone or in combination. The treatment has adverse effects including cardiomyopathy, hepatotoxicity, and nephrotoxicity. In addition, the development of resistance to chemo has been attributed to cancer relapse and low patient overall survivability. Multiple drug resistance development may be through numerous factors such as up-regulation of drug transporters, drug inactivation, alteration of drug targets and drug degradation. Doxorubicin is a widely used first line chemotherapeutic drug for a myriad of cancers. It has multiple intracellular targets, DNA intercalation, adduct formation, topoisomerase inhibition, iron chelation, reactive oxygen species generation and promotes immune mediated clearance of the tumor. Agents that can sensitize the resistant cancer cells to the chemotherapeutic drug are currently the focus to improve the clinical efficiency of cancer therapy. This review summarizes the recent 10-year research on the use of natural phytochemicals, inhibitors of apoptosis and autophagy, miRNAs, siRNAs and nanoformulations being investigated for doxorubicin chemosensitization.

     

Isolation of cold stress-responsive genes from Lepidium latifolium by suppressive subtraction hybridization

Suppression subtraction hybridization (SSH) libraries were constructed from RNA isolated from leaves of control and cold stress-induced Lepidium latifolium, a cold-tolerant plant species from high altitudes for isolation of cold-responsive genes. A total of 500 clones were obtained from the cold stress library. Dot blot expression analysis identified 157 clones that were upregulated and 75 that were downregulated during cold stress. These clones selected on the basis of their expression patterns on dot blot were sequenced. As much as 27 and 17 genes were identified from the forward and reverse libraries, respectively. The genes identified revealed homology with genes involved in diverse processes such as gene regulation/signaling, photosynthesis, DNA damage repair protein, pathogenesis-related protein, senescence-associated proteins and proteins with unknown functions.     

HLA-DRB1*04 gene polymorphisms and expressions profiles of interleukin-18 and interleukin-18 binding protein following in vitro stimulation in human peripheral blood mononuclear cells of healthy individuals and patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic arthritic condition that can lead to deformities and disabilities. Interleukin-18 (IL-18) is a proinflammatory cytokine known to play a role in the acute and chronic inflammatory phases of RA. IL-18 binding protein is the natural antagonist of IL-18 protein. We aim to identify the effect of HLA-DRB1*04 gene polymorphisms on IL-18 and IL-18BP gene expressions profiles as well as the time-course profiles following in vitro stimulation with mitogens. Peripheral blood mononuclear cells from 16 RA patients and 21 healthy controls were cultured for 1, 4, 8, 12, 24, 48 and 72 h following stimulation with either LPS or PHA. mRNA expression of IL-18 and IL 18BP were determined by quantitative real-time PCR using a comparative Ct (threshold cycle) method. IL-18 levels in supernatants were measured by enzyme-linked immunosorbent assay. Basal mRNA (4.5-fold) and protein levels of IL-18 were increased and IL-18BP mRNA expression was decreased (8-fold) in RA patients when compared to controls. Similarly, increased IL-18 levels were observed in active RA patients, whereas IL-18BP expression was increased in inactive patients. There was an increase in mRNA and protein levels of IL-18 in RA patients that peaked at 4 h and 8 h respectively following LPS stimulation. A similar profile was observed for IL-18BP; however, the expression level was higher in controls than RA patients. Persistent high production of IL-18 in RA is associated with disease progression and IL-18 BP seems to inhibit this activity.     

An integrative approach combining ion mobility mass spectrometry,X-ray crystallography,and nuclear magnetic resonance spectroscopy to study the conformational dynamics of α1-antitrypsin upon ligand binding

Native mass spectrometry (MS) methods permit the study of multiple protein species within solution equilibria, whereas ion mobility (IM)-MS can report on conformational behavior of specific states. We used IM-MS to study a conformationally labile protein (α₁-antitrypsin) that undergoes pathological polymerization in the context of point mutations. The folded, native state of the Z-variant remains highly polymerogenic in physiological conditions despite only minor thermodynamic destabilization relative to the wild-type variant. Various data implicate kinetic instability (conformational lability within a native state ensemble) as the basis of Z α₁-antitrypsin polymerogenicity. We show the ability of IM-MS to track such disease-relevant conformational behavior in detail by studying the effects of peptide binding on α₁-antitrypsin conformation and dynamics. IM-MS is, therefore, an ideal platform for the screening of compounds that result in therapeutically beneficial kinetic stabilization of native α₁-antitrypsin. Our findings are confirmed with high-resolution X-ray crystallographic and nuclear magnetic resonance spectroscopic studies of the same event, which together dissect structural changes from dynamic effects caused by peptide binding at a residue-specific level. IM-MS methods, therefore, have great potential for further study of biologically relevant thermodynamic and kinetic instability of proteins and provide rapid and multidimensional characterization of ligand interactions of therapeutic interest.PDB Code(s): 4PYW     

The ligand specificity of yeast Rad53 FHA domains at the +3 position is determined by nonconserved residues

On the basis of the results from our laboratory and others, we recently suggested that the ligand specificity of forkhead-associated (FHA) domains is controlled by variations in three major factors: (i) residues interacting with pThr, (ii) residues recognizing the +1 to +3 residues from pThr, and (iii) an extended binding surface. While the first factor has been well established by several solution and crystal structures of FHA-phosphopeptide complexes, the structural bases of the second and third factors are not well understood and are likely to vary greatly between different FHA domains. In this work, we proposed and tested the hypothesis that nonconserved residues G133 and G135 of FHA1 and I681 and D683 of FHA2, located outside of the core FHA region of yeast Rad53 FHA domains, contribute to the specific recognition of the +3 position of different phosphopeptides. By rational mutagenesis of these residues, the specificity of FHA1 has been changed from predominantly pTXXD to be equally acceptable for pTXXD, pTXXL, and pYXL, which are similar to the specificities of the FHA2 domain of Rad53. Conversely, the +3 position specificity of FHA2 has been engineered to be more like FHA1 with the I681A mutation. These results were based on library screening as well as binding analyses of specific phosphopeptides. Furthermore, results of structural analyses by NMR indicate that some of these residues are also important for the structural integrity of the loops.