Rupak Mukhopadhyay

Mucosal Tolerance to a Combination of ApoB and HSP60 Peptides Controls Plaque Progression and Stabilizes Vulnerable Plaque in Apobtm2SgyLdlrtm1Her/J Mice

Oral tolerance to auto antigens reduces the development of atherosclerosis in mouse models. However, the effect of immune tolerance to multiple self antigenic peptides in plaque progression and stabilization is not known. We studied the protective effect of mucosal tolerance to peptides from apolipoprotein B (ApoB; 661–680) and heat shock protein 60 (HSP60; 153–163), in combination with diet, in the prevention of atherosclerotic lesion progression and plaque stabilization in ApoBtm25gyLDLrtm1Her mice. We found that oral administration of five doses of a combination of ApoB and HSP60 peptides (20 µg/mice/dose) induced tolerance to both the peptides and reduced early plaque development by 39.9% better than the individual peptides (ApoB = 28.7%;HSP60 = 26.8%)(P<0.001). Oral tolerance to combination of peptides along with diet modification arrested plaque progression by 37.6% which was associated with increases in T-regulatory cell and transforming growth factor-β expression in the plaque and peripheral circulation. Reduced macrophage infiltration and tumor necrosis factor-α expression in the plaque was also observed. Tolerance with continued hypercholesterolemia resulted in 60.8% reduction in necrotic core area suggesting plaque stabilization, which was supported by reduction in apoptosis and increased efferocytosis demonstrated by greater expression of receptor tyrosine kinase Mer (MerTK) in the plaque. Tolerance to the two peptides also reduced the expression of matrix metalloproteinase 9, tissue factor, calprotectin, and increased its collagen content. Our study suggests that oral tolerance to ApoB and HSP60 peptide combination induces CD4+ CTLA4+ Tregs and CD4+CD25+Foxp3+ Tregs secreting TGF-β, which inhibit pathogenic T cell response to both peptides thus reducing the development and progression of atherosclerosis and provides evidence for plaque stabilization in ApoBtm25gyLDLrtm1Her mice.

A Finite Element Algorithm for the Prediction of Steady-State Temperatures of Rolling Tires

Abstract A review of the literature on the numerical techniques used for the determination of tire temperatures shows that many attempts have been made to simulate tire temperatures with axisymmetric geometry through a simple decoupled representation of the total thermomechanical behavior. The deformation models used in these studies are primarily statically loaded tires with centrifugal forces to simulate tire-rolling behavior at different speeds. These techniques are usually limited to axisymmetric tires, which make the models applicable to only smooth or circumferential grooved tires. In this study, a finite element (FE) algorithm is developed using Petrov-Galerkin Eulerian technique in cylindrical coordinates. An objective of this approach is to provide a technique that is more appropriate for extension to nonaxisymmetric tires with tread patterns. The developed algorithm has been implemented for the prediction of three-dimensional operating temperatures for axisymmetric tires through a simple decoupl...

Green silver nanoparticles: enhanced antimicrobial and antibiofilm activity with effects on DNA replication and cell cytotoxicity

Biofabricated metal nanoparticles are biocompatible, inexpensive and eco-friendly. They find immense utility in the domain of biomedical and materials science. The present work focuses on the ‘green’ synthesis of silver nanoparticles (AgNPs) using the methanolic extract of Syzygium cumini leaf. AgNPs showed the characteristic surface plasmon resonance peak at 442 nm. The XRD pattern confirmed the formation of face centered cubic AgNPs. The nanoparticles were uniformly distributed within a narrow size range of 10–20 nm. The particles exhibited significant antimicrobial activity against a panel of pathogens like Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Klebsiella pneumoniae, Pseudomonas aeruginosa, Mycobacterium smegmatis, Trichophyton rubrum, Aspergillus sp and Candida albicans. Alterations in membrane permeability of AgNP treated microbial cells were evident from scanning electron microscope images. The replication fidelity of small (1500 bp) DNA fragments in the presence of AgNPs was compromised in a dose-dependent fashion and addition of bovine serum albumin (BSA) to PCR reactions reversed the effect of AgNPs. Besides, the prepared nanoparticles inhibited biofilm formation in a wide range of AgNP concentrations. Significantly, cytotoxicity assays showed good compatibility of AgNPs with human embryonic kidney cells (HEK 293). In summary, the study suggests an eco-friendly, cost effective and biocompatible approach for synthesizing AgNPs, which may act as a potential template for designing novel antibacterial, antifungal and antibiofilm agents.

A study of the relationship between Magic Formula coefficients and tyre design attributes through finite element analysis

Pacejkas Magic Formula Tyre Model is widely used to represent force and moment characteristics in vehicle simulation studies meant to improve handling behaviour during steady-state cornering. The experimental technique required to determine this tyre model parameters is fairly involved and highly sophisticated. Also, total test facilities are not available in most countries. As force and moment characteristics are affected by tyre design attributes and tread patterns, manufacturing of separate tyres for each design alternative affects tyre development cycle time and economics significantly. The objective of this work is to identify the interactions among various tyre design attributes-cum-operating conditions and the Magic Formula coefficients. This objective is achieved by eliminating actual prototyping of tyres for various design alternatives as well as total experimentation on each tyre through simulation using finite element analysis. Mixed Lagrangian–Eulerian finite element technique, a specialized technique in ABAQUS, is used to simulate the steady-state cornering behaviour; it is also efficient and cost-effective. Predicted force and moment characteristics are represented as Magic Formula Tyre Model parameters through non-linear least-squares fit using MATLAB. Issues involved in the Magic Formula Tyre Model representation are also discussed. A detailed analysis is made to understand the influence of various design attributes and operating conditions on the Magic Formula parameters. Tread pattern, tread material properties, belt angle, inflation pressure, frictional behaviour at the tyre–road contact interface and their interactions are found to significantly influence vehicle-handling characteristics.

Mouse models of atherosclerosis: explaining critical roles of lipid metabolism and inflammation

Atherosclerosis is the most common cause of death globally. It is a complex disease involving morphological and cellular changes in vascular walls. Studying molecular mechanism of the disease is hindered by disease complexity and lack of robust noninvasive diagnostics in human. Mouse models are the most popular animal models that allow researchers to study the mechanism of disease progression. In this review we discuss the advantage and development of mouse as a model for atherosclerotic research. Along with commonly used models, this review discusses strains that are used to study the role of two critical processes associated with the disease—lipid metabolism and inflammation.

Antiatherogenic Roles of Dietary Flavonoids Chrysin, Quercetin, and Luteolin.

Abstract: Cardiovascular diseases (CVDs) are the commonest cause of global mortality and morbidity. Atherosclerosis, the fundamental pathological manifestation of CVDs, is a complex process and is poorly managed both in terms of preventive and therapeutic intervention. Aberrant lipid metabolism and chronic inflammation play critical roles in the development of atherosclerosis. These processes can be targeted for effective management of the disease. Although managing lipid metabolism is in the forefront of current therapeutic approaches, controlling inflammation may also prove to be crucial for an efficient treatment regimen of the disease. Flavonoids, the plant-derived polyphenols, are known for their antiinflammatory properties. This review discusses the possible antiatherogenic role of 3 flavonoids, namely, chrysin, quercetin, and luteolin primarily known for their antiinflammatory properties.

Comparison of Oral Tolerance to ApoB and HSP60 Peptides in Preventing Atherosclerosis Lesion Formation in Apob48−/Ldlr− Mice

Antigen-specific immune modulation is emerging as an attractive therapeutic option to prevent atherosclerosis. We compared the efficacy of oral administration of peptides derived from apolipoprotein B (ApoB; 661–680) and heat shock protein 60 (HSP60; 153–163), in the prevention of atherosclerotic lesion formation hyperlipidemic low density lipoprotein receptordeficient (LDLr−/−), apolipoprotein B-100 only (apoB100/100) mice model. Oral administration of peptides induced tolerance as seen by an increase in regulatory T cells in the peripheral immune system. Tolerance to ApoB peptide reduced plaque development by 28.7% () while HSP60 was effective in reducing lesion development by 26.8% in ApoB48/LDLr−/− mice. While tolerance to HSP60 resulted in increase in anti-inflammatory cytokines (IL10 and TGF-β), ApoB tolerance was effective in reducing the lipid deposition in the lesion. Our results suggest that the two peptides have distinct mechanisms of controlling the development of atherosclerosis in mice.

Utilization of two agrowastes for adsorption and removal of methylene blue: kinetics and isotherm studies

Fresh water streams contaminated with synthetic dye-containing effluents pose a threat to aquatic and human life either by preventing aquatic photosynthesis or by entering into the food chain. Adsorptive removal of such dyes with potent biosorbents is an important technique to reduce bioaccumulation and biomagnifications of the dyes in human life. We report use of betel nut (BN) husk and banana peel (BP), two most abundant ligno-cellulosic wastes, as efficient adsorbents for the removal of the basic dye methylene blue (MB). The adsorption by BN and BP was consistently high over wide ranges of pH and temperature, suggesting their dye removal potential in diverse conditions. Physico-chemical studies, e.g. scanning electron microscopy and Fourier transform-infrared spectroscopy studies, revealed changes in surface topology and functional moieties of BN and BP post adsorption, implying dye interaction with the biomass surface. The dye adsorption in both cases followed pseudo-second-order kinetics. While adsorption of MB by BN was better fitted with the Temkin isotherm model, adsorption with BP followed both Langmuir and Freundlich isotherm models. Our studies concluded that both adsorbents efficiently remove MB from its aqueous solution with BP proved to be marginally superior to BN.

Purification and partial characterization of an anticoagulant PLA2 from the venom of Indian Daboia russelii that induces inflammation through upregulation of proinflammatory mediators

The present study describes the purification and partial characterization of a basic anticoagulant PLA2 enzyme named as Rv(i) PLA2 from the venom of Indian Daboia russelii. The molecular mass of the protein was found to be 13,659.65 Da, and peptide mass fingerprinting revealed that it belongs to group II PLA2 family. The peptide sequence showed similarity to uncharacterized basic PLA2 enzyme having an accession no. of P86368 reported from Sri Lankan D. russelii. Rv(i) PLA2 exhibited strong phospholipase A2 and anticoagulant activity. It also induced expression of COX‐2 and TNF‐α mRNA in a dose‐dependent manner in phorbol 12‐myristate 13‐acetate differentiated THP‐1 cells, which play a crucial role during inflammation. Chemical modification of His residue in Rv(i) PLA2 with p‐bromophenacyl bromide abolished the enzymatic, anticoagulant, and inflammatory activities. The result indicates that the catalytic site of Rv(i) PLA2 might play a vital role in inducing inflammation at the bite site during D. russelii envenomation.

Daboxin P, a Major Phospholipase A2 Enzyme from the Indian Daboia russelii russelii Venom Targets Factor X and Factor Xa for Its Anticoagulant Activity.

In the present study a major protein has been purified from the venom of Indian Daboia russelii russelii using gel filtration, ion exchange and Rp-HPLC techniques. The purified protein, named daboxin P accounts for ~24% of the total protein of the crude venom and has a molecular mass of 13.597 kDa. It exhibits strong anticoagulant and phospholipase A2 activity but is devoid of any cytotoxic effect on the tested normal or cancerous cell lines. Its primary structure was deduced by N-terminal sequencing and chemical cleavage using Edman degradation and tandem mass spectrometry. It is composed of 121 amino acids with 14 cysteine residues and catalytically active His48 -Asp49 pair. The secondary structure of daboxin P constitutes 42.73% of α-helix and 12.36% of β-sheet. It is found to be stable at acidic (pH 3.0) and neutral pH (pH 7.0) and has a Tm value of 71.59 ± 0.46°C. Daboxin P exhibits anticoagulant effect under in-vitro and in-vivo conditions. It does not inhibit the catalytic activity of the serine proteases but inhibits the activation of factor X to factor Xa by the tenase complexes both in the presence and absence of phospholipids. It also inhibits the tenase complexes when active site residue (His48) was alkylated suggesting its non-enzymatic mode of anticoagulant activity. Moreover, it also inhibits prothrombinase complex when pre-incubated with factor Xa prior to factor Va addition. Fluorescence emission spectroscopy and affinity chromatography suggest the probable interaction of daboxin P with factor X and factor Xa. Molecular docking analysis reveals the interaction of the Ca+2 binding loop; helix C; anticoagulant region and C-terminal region of daboxin P with the heavy chain of factor Xa. This is the first report of a phospholipase A2 enzyme from Indian viper venom which targets both factor X and factor Xa for its anticoagulant activity.