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The world-wide rate of incidence of cancer disease has been only modestly contested by the past and current preventive and interventional strategies. Hence, the global effort towards novel ideas to contain the disease still continues. Constituents of human diets have in recent years emerged as key regulators of carcinogenesis, with studies reporting their inhibitory potential against all the three stages vis-a-vis initiation, promotion and progression. Unlike drugs which usually act on single targets, these dietary factors have an advantage of multi-targeted effects and pleiotropic action mechanisms, which are effective against cancer that manifest as a micro-evolutionary and multi-factorial disease. Since most of the cellular targets have been identified and their consumption considered relatively safe, these diet-derived agents often appear as molecules of interest in repurposing strategies. Currently, many of these molecules are being investigated for their ability to influence the aberrant alterations in cell's epigenome for epigenetic therapy against cancer. Targeting the epigenetic regulators is a new paradigm in cancer chemoprevention which acts to reverse the warped-up epigenetic alterations in a cancer cell, thereby directing it towards a normal phenotype. In this review, we discuss the significance of dietary factors and natural products as chemopreventive agents. Further, we corroborate the experimental evidence from existing literature, reflecting the ability of a series of such molecules to act as epigenetic modifiers in cancer cells, by interfering with molecular events that map the epigenetic imprints such as DNA methylation, histone acetylation and non-coding RNA mediated gene regulation.

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OBJECTIVES: Increased levels of serum Immunoglobulin-E (IgE) and different genetic variants of cytokines are common biochemical manifestation in Allergy. The current study was aimed to study the association of IgE and different variants of Interleukin-4 (IL-4), and Interleukin-13 (IL-13) genes with different kind of allergies. METHODS: A pre-tested questionnaire was used to collect all the dietary, life style and clinical details by a trained staff. A blood sample of 2 ml each was collected in coagulated and anti-coagulated vials. DNA and serum samples were extracted and stored until further use. Serum IgE were estimated by ELISA while as the genotypic analysis was done by PCR-RFLP methods. RESULTS: Statistically a significant difference of serum IgE levels were observed among cases and controls (P < 0.05). The observed significant difference of serum IgE levels were retained among subjects who also harboured variant genotypes of IL-4 and IL-13 genes (P < 0.05). Additionally, the above genetic variants significantly modified the risk of allergy when stratification was done based on various clinical characteristics. CONCLUSION: Our study suggests that increased IgE levels and in association with variant forms of IL-4 and IL-13 genes are significantly associated with different types of allergies in study population.

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Drug protein interactions have gained considerable attention over the past many years. In the current communication the association of muscle cystatin (MC) with anti-rheumatic drugs methotrexate and dexamethasone was studied by thiol proteinase inhibitor assay, ultra violet (UV) absorption, fluorescence spectroscopy, and fluorescence transform infra-red spectroscopy (FTIR). A static pattern of quenching was noticed between muscle cystatin and methotrexate (MTX). Binding constant (Ka) of methotrexate to muscle cystatin was found to be 1 × 10-7 M-1 and the stoichiometry of binding was calculated to be one. Fluorescence measurement of the emission quenching reveals that the quenching process of cystatin by dexamethasone (DXN) was also static. The stoichiometry of binding and binding constant was also obtained. Additional evidence regarding MTX-MC and DXN-MC was obtained from UV spectroscopy and FTIR spectroscopic results. Such spectroscopic studies would help in modelling new candidate drugs for rheumatoid arthritis based on their cystatin binding profile.Communicated by Ramaswamy H. Sarma.

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Several mammalian proteins form pathological deposits under nonphysiological conditions that are associated with many degenerative diseases. Protein aggregation is associated with aging, as well as a variety of diseases, including cystic fibrosis, amyotrophic lateral sclerosis (ALS), and hypertrophic cardiomyopathy. There is a lack of any potential anti-amyloidogenic agents and therapeutics till date. Polyphenols have been accredited with myriad biological effects. An analysis of the effects of natural agents like baicalin (BC) and gallocatechin (GC) on aggregation process can open new avenues for the treatment of protein misfolding diseases. Thus, investigation of the effects of these flavonoids on Buffalo Heart Cystatin (BHC) aggregation induced by a reactive metabolic dialdehyde, glyoxal (GO), was taken up. Results have shown that elevated concentration of GO forms aggregates of BHC, which was characterized by an increase in the ANS fluorescence intensity, an increase in ThT fluorescence intensity, red shift in Congo red absorbance, negative ellipticity peak at 217 nm in the far-UVCD and BHC aggregates displaying by TEM. Using fluorescence spectroscopic analysis with Thioflavin T, CD and electron microscopic studies, anti-aggregation effects of polyphenols, BC and GC were analyzed. The study showed that BC and GC produced concentration-dependent anti-aggregation effects with GC producing a more pronounced effect than BC. The study proposed a mechanistic approach assuming structural constraints and specific aromatic interactions of polyphenols with sheets of BHC aggregates.

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The non-enzymatic reaction between reducing sugars and proteins has received increased attention in nutritional and medical research recently. In the current manuscript, effect of glycation in structural changes of human serum albumin (HSA) by the metabolites of glucose such as glyoxal, methylglyoxal and glyceraldehyde was studied using different spectroscopy techniques. Glycation of HSA was monitored by following advanced glycation end-products (AGEs) fluorescence changes, HSA intrinsic fluorescence measurement, extrinsic fluorescence using 8-analino 1-nephthlene sulfonic acid (ANS) dye, and circular dichroism (CD) studies. AGEs were formed within 7 days of incubation with glyoxal, methylglyoxal and glyceraldehyde. However, methylglyoxal induced significant structural changes in HSA compared with glyoxal and glyceraldehydes. Moreover, ANS binding to native and glycated-HSA showed difference in binding pattern of these metabolites to HSA. The CD spectrum revealed changes in the secondary structure of HSA upon glycation when compared to native HSA. Furthermore, the MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide) assay established the cytotoxicity of the glycated- HSA towards human liver carcinoma (HepG2) cell lines via the production of reactive oxygen species.

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OBJECTIVE: To investigate the aggregation and fibrillation of insulin at low pH and moderate temperature; and to further test the aggregated insulin for its cytotoxicity on human neuroblastoma (SH-SY5Y) cell line and inhibition of the cytotoxicity by black seeds (Nigella sativa) extract. METHODS: Bovine pancreatic insulin was incubated at pH 2.0, 45 ℃ under stirring condition at 400 r/min for 24 h. Amyloids like structures in the aggregated insulin were characterized using various techniques such as thioflavin T assay (ThT), 1-anilinonaphthalene-8-sulfonic acid (ANS) fluorescence, circular dichroism (CD) and dynamic light scattering (DLS). Moreover, cytotoxicity of aggregated insulin was monitored on SH-SY5Y cell line in the presence and absence of black seeds extract using standard 3-(4,5-dimethylthiazol-2-Yl)-2,5-diphenyltetrazolium bromide (MTT), lactate dehydrogenase (LDH) and reactive oxygen species (ROS) assay kit. RESULTS: Our finding demonstrated that insulin under the mentioned conditions formed amyloid-like structure. ANS binding to aggregated insulin showed increase in fluorescence, suggesting structural change and increase in hydrophobicity in insulin occurring during the fibril formation. DLS measurement revealed progressive increase in hydrodynamic radius of aggregated insulin. Cytotoxicity assays illustrated aggregated insulin induced apoptosis in SH-SY5Y cell through ROS formation. Moreover, LDH measurement showed aggregated insulin triggered membrane damage in SH-SY5Y cell lines. Black seeds extract was found to inhibit amyloid formation and protected the cells against amyloid toxicity. CONCLUSION: Insulin molded into amyloid like structure at low pH and under stirring conditions. Characterization of insulin aggregates illustrated conformational change in insulin and it experiences α-helix to ß-sheet transition during the course of fibrillation. Black seeds extract inhibited amyloid progression of insulin via ROS scavenging and restrained the cytotoxicity caused by insulin fibrils suggesting black seeds containing polyphenols may serve as a lead structure to a novel anti-amyloidogenic drugs.

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The drug-protein interaction has been the subject of increasing interest over the decades. In the present communication, the interaction of liver cystatin with anti-cancer (adriamycin) and anti-hepatitis (adevofir dipivoxil) drugs was studied by thiol-protease inhibitory assay, UV absorption, fluorescence spectroscopy and circular dichroism (CD). A static type of quenching was observed between the protein and the drug molecules. Binding constant (Ka) of adriamycin to liver cystatin (LC) was found to be 1.08 × 10(6) M(-1). Moreover, binding site number was found to be 2. Importantly, cystatin loses its activity in the presence of adriamycin. However, intrinsic fluorescence studies in the presence of adevofir dipivoxil showed enhancement in the fluorescence intensity suggesting that binding of adevofir to LC caused unfolding of the protein. The unfolding of the test protein was also accompanied by significant loss of inhibitory activity. CD spectroscopy result showed, both adriamycin and adevofir dipivoxil caused perturbation in the secondary structure of liver cystatin. The possible implications of these results will help in combating drug induced off target effects.

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Regulation of the cysteine protease activity is imperative for proper functioning of the various organ systems. Elevated activities of cysteine proteinases due to impaired regulation by the endogenous cysteine proteinase inhibitors (cystatins) have been linked to liver malignancies. To gain an insight into these regulatory processes, it is essential to purify and characterise the inhibitors, cystatins. Present study was undertaken to purify the inhibitor from the liver. The purification was accomplished in four steps: alkaline treatment, ammonium sulphate fractionation, acetone precipitation and gel filtration column (Sephacryl S-100 HR). The eluted protein exhibited inhibitory activity towards papain, and its purity was further reaffirmed using western blotting and immunodiffusion. The purified inhibitor (liver cystatin (LC)) was stable in the pH range of 6-8 and temperature up to 45 °C. In view of the significance of kinetics parameters for drug delivery, the kinetic parameters of liver cystatin were also determined. LC showed the greatest affinity for papain followed by ficin and bromelain. UV and fluorescence spectroscopy results showed that binding of LC with thiol proteases induced changes in the environment of aromatic residues. Recent advances in the field of proteinase inhibitors have drawn attention to the possible use of this collected knowledge to control pathologies.

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Cystatins are thiol proteinase inhibitors ubiquitously present in the mammalian body. They serve a protective function to regulate the activities of endogenous proteinases, which may cause uncontrolled proteolysis and damage. In the present study, the effect of benzo(a)pyrene [BaP] on lung cystatin was studied to explore the hazardous effects of environmental pollutant on structural and functional integrity of the protein. The basic binding interaction was studied by UV-absorption, FT-IR, and fluorescence spectroscopy. The enhancement of total protein fluorescence with a red shift of 5 nm suggests structural scratch of lung cystatin by benzo(a)pyrene. Further, ANS binding studies reaffirm the unfolding of the thiol protease inhibitor (GLC-I) after treating with benzo(a)pyrene. The results of FT-IR spectroscopy reflect perturbation of the secondary conformation (alpha-helix to ß-sheet) in goat lung cystatin on interaction with BaP. Finally, functional inactivation of cystatin on association with BaP was checked by its papain inhibitory activity. Benzo(a)pyrene (10 µM) caused complete inactivation of goat lung cystatin. Benzo(a)pyrene-induced loss of structure and function in the thiol protease inhibitor could provide a caution for lung injury caused by the pollutants and smokers.

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Cystatins are thiol proteinase inhibitors ubiquitously present in mammalian body and serve various important physiological functions. In the present study, we examined the effects of acid denaturation on newly identified thiol protease inhibitors from the lungs of Capra hircus (Goat) with a focus on protein conformational changes and amyloid fibril formation. Acid denaturation as studied by CD (Circular Dichroism) and fluorescence spectroscopy showed that purified inhibitor named GLC (Goat Lung Cystatin) populates three partly unfolded species, a native like state at pH 3.0, a partly unfolded intermediate at pH2.0, and unstructured unfolded state at pH 1.0, from each of which amyloid like fibrils grow as assessed by thioflavin T (ThT) spectroscopy. The result showed, native like structure formed at pH 3.0 is more responsive towards amyloid formation when compare to other conformation of proteins. Morphology of the protein species incubated for amyloid process was observed using transmission electron microscopy (TEM). Moreover, anti-fibrillogenic effects of curcumin and quercetin were analysed using ThT binding assay. Curcumin and quercetin produced a concentration dependent decline inThT fluorescence suggesting deaggregation of the fibrils. When added prior to amyloid fibril initiation 50 µM curcumin inhibited amyloid aggregation. However, more quercetin is needed to prevent the same extent of fibrillation. Implications for therapeutics in view of polyphenols as essential nutrients are suggested in lung diseases.

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MicroRNAs (miRNAs) have emerged as key gene regulators controlling the expression of many target mRNAs. The nervous system harbors highest number of miRNAs expressed in a spatially and temporally controlled manner. Neural miRNAs have been accredited with diverse roles like regulation of neural differentiation, synaptogenesis, inflammation, memory and cognition. Their aberrant expression and/or function has been linked to various neurodegenerative, neuroinflammatory and stress related disorders. Recent evidence indicates that miRNAs are essential to the fine tuning of the immune responses. Besides controlling the maturation, proliferation and differentiation of myeloid and lymphoid lineages they participate directly by modulating the signaling pathways through the Toll-like receptors and thus the cytokine response. The miRNAs commuting between the nervous and immune systems and affecting the neuro-immune dialogue are emerging.

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Goat liver cystatin was subjected to various chemical modifications in order to ascertain the amino acid residues responsible for its structural and functional integrity. Modification of tryptophan by HNBB led to the complete inactivation of the protein. The inactivation was also accompanied by the complete loss of tryptophan fluorescence at 340 nm. The reaction of liver cystatin with HNBB yielded a characteristic decrease in absorbance at 280 nm. Acetylation of the amino groups of liver cystatin was carried out in the presence of acetic anhydride. The acetylated cystatin showed a decrease in fluorescence intensity at 335 nm which could be attributed to the modification of tyrosine residue due to side reaction.

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This report summarizes the effect of methanol, glycerol and polyol (PEG) on the acid induced state of goat liver cystatin by various spectroscopic techniques. Native goat liver cystatin (LC) has a fluorescence maximum at 340 nm, whereas the acid induced state shows a red shift of 15 nm with enhanced fluorescence intensity. Addition of 80% (V/V) methanol and glycerol both were found to stabilise the acid induced state of goat liver cystatin. However, glycerol was found to be a better stabilising agent than methanol. The unfolded state of liver cystatin obtained at pH 2 underwent a series of conformational changes when exposed to PEG-300 at varying concentrations. Tertiary structure was stabilized only at low concentrations of PEG-300 but higher concentrations resulted in the loss of tertiary structure.

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Studies on the role of endogenous metabolites such as bilirubin and their interactions with biomolecules have attracted considerable attention over the past several years. In this work, the interaction of bilirubin (BR) with purified goat liver cystatin (LC) was studied using fluorescence and ultraviolet (UV) spectroscopy. The fluorescence data proved that the fluorescence quenching of liver cystatin by BR was the result of BR-cystatin complex formation. Stern-Volmer analysis of fluorescence quenching data showed the binding constant to be 9.27 x 104 M⁻¹ and the number of binding sites to be close to unity. The conformation of the BR-cystatin complex was found to change upon varying the pH of the complex. The BR-cystatin complex was found to have reduced papain inhibitory activity. Photo-illumination of BR-cystatin complex causes perturbation in the micro-environment of goat liver cystatin as indicated by red-shift. This report summarizes our research efforts to reveal the mechanism of interaction of bilirubin with liver cystatin.

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The Cystatins constitute a large group of evolutionary related proteins with diverse biological activities. They have been recently realized as instrumental in myriad of pathophysiological conditions. They have been implicated in various pathological conditions. The degree of malignancy of various types of cancer cells has been found to be inversely associated with the expression of cystatins. Cystatins have been found to have various antimicrobial, antiviral and immunomodulatory properties. Keeping in view as their being prospective drug targets and anti-disease options this review explores the role of cytoplasmic and cell secreted cystatins in various human diseases.