Lack of T-cell-mediated IL-2 and TNFα production is linked to decreased CD58 expression in intestinal tissue during acute simian immunodeficiency virus infection.

For an effective T-cell activation and response, co-stimulation is required in addition to the antigen-specific signal from their antigen receptors. The CD2/CD58 interaction is considered as one of the most important T-cell co-stimulatory pathways for T-cell activation and proliferation, and its role in regulating intestinal T-cell function in acute and chronic SIV -infected macaques is poorly documented. Here, we demonstrated a significant reduction of CD58 expression in both T- and B-cell populations during acute SIV infection along with high plasma viral load and a loss of intestinal CD4+ T cells compared to SIV-uninfected control macaques. The reduction of CD58 expression in T cells was correlated with the reduced expression of T-cell-mediated IL-2 and TNFα production. Together, these results indicate that reduction in the CD2/CD58 interaction pathway in mucosal lymphocytes might play a crucial role in mucosal T-cell dysfunction during acute SIV/HIV infection.

Inhibition of Oxidative Stress and Enhancement of Cellular Activity by Mushroom Lectins in Arsenic Induced Carcinogenesis.

Chronic arsenicosis is a major environmental health hazard throughout the world, including India. Animals and human beings are affected due to drinking of arsenic contaminated ground water, due to natural mineral deposits, arsenical pesticides or improperly disposed arsenical chemicals. Arsenic causes cancer with production of free radicals and reactive oxygen species (ROS) that are neutralized by an elaborate antioxidant defense system consisting of enzymes and numerous non-enzymatic antioxidants. Dietary antioxidant supplements are useful to counteract the carcinogenesis effects of arsenic. Oyster mushroom lectins can be regarded as ingredients of popular foods with biopharmaceutical properties. A variety of compounds have been isolated from mushrooms, which include polysaccharides and polysaccharopeptides with immune-enhancing effects. Lectins are beneficial in reducing arsenic toxicity due to anticarcinogenetic roles and may have therapeutic application in people suffering from chronic exposure to arsenic from natural sources, a global problem that is especially relevant to millions of people on the Indian subcontinent.

Transforming growth factor-ß1 regulated phosphorylated AKT and interferon gamma expressions are associated with epithelial cell survival in rhesus macaque colon explants.

Transforming growth factor-ß1 (TGF-ß1) is an important immunoregulatory cytokine that plays an obligate role in regulating T-cell functions. Here, we demonstrated the role of TGF-ß1 in regulating the survival of intestinal epithelial cells (ECs) in rhesus colon explant cultures using either anti-TGF-ß1 antibody or recombinant TGF-ß1 proteins. Neutralization of endogenous TGF-ß1 using anti-TGF-ß1 antibodies induced apoptosis of both intestinal ECs and lamina propria (LP) cells. Additionally, endogenous TGF-ß1 blocking significantly increased expression of IFNγ, TNFα, CD107a and Perforin in LP cells compared to media and isotype controls. A significant decrease in pAKT expression was detected in anti-TGF-ß1 MAbs treated explants compared to isotype and rTGF-ß1 protein treated explants. Our results demonstrated TGF-ß1 regulated pAKT and IFNγ expressions were associated with epithelial cell survival in rhesus macaque colon explants and suggest a potential role of mucosal TGF-ß1 in regulating intestinal homeostasis and EC integrity.

Characterization of arsenic-induced cytotoxicity in liver with stress in erythrocytes and its reversibility with Pleurotus florida lectin.

Arsenic is one of the most hazardous substances in the environment known to cause toxicity in multiple organs. Cell adhesion, morphological alterations, cell proliferation, terminal deoxyuridine triphosphate nick-end labeling (TUNEL) and caspase-3/CPP32 fluorometric protease assay were important biomarkers to assess apoptosis in cells. This study aimed to evaluate arsenic-induced apoptosis in the hepatocytes of rat and its protective efficacy with coadministration of ascorbic acid (AA) and Pleurotus florida lectin (PFL) individually. Results of the present study also showed that arsenic caused cytotoxicity by elevating morphological alterations, TUNEL-positive nuclei, caspase-3 activity and DNA damage and reducing cell adhesion and cell proliferation in a time-dependent manner. The apoptosis in hepatocytes was reverted to normal value after coadministration of mushroom lectin in arsenic-exposed rat. The study provided significant evidence that PFL has antiapoptotic property against arsenic-induced toxicity. The beneficial effect of PFL was proportional to its duration of exposure. Retard activities of superoxide dismutase and catalase, enhanced lipid peroxidation as well as protein carbonyl in erythrocytes caused by arsenic could also be maintained toward normalcy by supplementation of AA and PFL. These antioxidative effects were exhibited in a time-dependant manner. In rat, treatment with AA and PFL prevented alteration of plasma enzyme activities caused by arsenic. The results concluded that treatment with PFL has significant role in protecting animals from arsenic-induced erythrocytic damage. This finding might be of therapeutic benefit in people suffering from chronic exposure to arsenic from natural sources, a global problem especially relevant to millions of people on the Indian subcontinent.

Lack of interleukin-10-mediated anti-inflammatory signals and upregulated interferon gamma production are linked to increased intestinal epithelial cell apoptosis in pathogenic simian immunodeficiency virus infection.

UNLABELLED: Interleukin-10 (IL-10) is an immunomodulatory cytokine that is important for maintenance of epithelial cell (EC) survival and anti-inflammatory responses (AIR). The majority of HIV infections occur through the mucosal route despite mucosal epithelium acting as a barrier to human immunodeficiency virus (HIV). Therefore, understanding the role of IL-10 in maintenance of intestinal homeostasis during HIV infection is of interest for better characterization of the pathogenesis of HIV-mediated enteropathy. We demonstrated here changes in mucosal IL-10 signaling during simian immunodeficiency virus (SIV) infection in rhesus macaques. Disruption of the epithelial barrier was manifested by EC apoptosis and loss of the tight-junction protein ZO-1. Multiple cell types, including a limited number of ECs, produced IL-10. SIV infection resulted in increased levels of IL-10; however, this was associated with increased production of mucosal gamma interferon (IFN-γ) and tumor necrosis factor alpha (TNF-α), suggesting that IL-10 was not able to regulate AIR. This observation was supported by the downregulation of STAT3, which is necessary to inhibit production of IFN-γ and TNF-α, and the upregulation of SOCS1 and SOCS3, which are important regulatory molecules in the IL-10-mediated AIR. We also observed internalization of the IL-10 receptor (IL-10R) in mucosal lymphocytes, which could limit cellular availability of IL-10 for signaling and contribute to the loss of a functional AIR. Collectively, these findings demonstrate that internalization of IL-10R with the resultant impact on IL-10 signaling and dysregulation of the IL-10-mediated AIR might play a crucial role in EC damage and subsequent SIV/HIV pathogenesis. IMPORTANCE: Interleukin-10 (IL-10), an important immunomodulatory cytokine plays a key role to control inflammatory function and homeostasis of the gastrointestinal mucosal immune system. Despite recent advancements in the study of IL-10 and its role in HIV infection, the role of mucosal IL-10 in SIV/HIV infection in inducing enteropathy is not well understood. We demonstrated changes in mucosal IL-10 signaling during SIV infection in rhesus macaques. Disruption of the intestinal epithelial barrier was evident along with the increased levels of mucosal IL-10 production. Increased production of mucosal IFN-γ and TNF-α during SIV infection suggested that the increased level of mucosal IL-10 was not able to regulate anti-inflammatory responses. Our findings demonstrate that internalization of IL-10R with the resultant impact on IL-10 signaling and dysregulation of the IL-10-mediated anti-inflammatory responses might play a crucial role in epithelial cell damage and subsequent SIV/HIV pathogenesis.

Arsenic residue in the products and by-products of chicken and ducks: a possible concern of avian health and environmental hazard to the population in West Bengal, India.

Arsenicosis caused due to drinking of arsenic contaminated ground water is a major environmental health hazard throughout the world. We evaluated the ecotoxicological effect of arsenic on chicken and duck in an arsenic endemic zone. The concentration of arsenic was higher in chicken and duck feed and their by-products than that in the respective samples of control area. Arsenic concentration in the eggs of both chicken and duck was higher than that in the respective samples of control area. Thus, we concluded that arsenic enters into food chain through the intake of contaminated eggs. Furthermore, adverse health effect of arsenic on avian population is due to the alteration in haematobiochemical indices.

Subclinical arsenicosis in cattle in arsenic endemic area of West Bengal, India.

Arsenic is ubiquitously found metalloid that commonly contaminates drinking water and agricultural food. To minimise the ecotoxicological effect of arsenic in the environment, it is important to ameliorate the deleterious effects on human and animal health. We investigated the effects of arsenic on cattle by estimating arsenic concentration in biological samples of cattle that consumed contaminated drinking water and feedstuffs directly or indirectly. We have selected arsenic prone village that is Ghentugachi, Nadia district, West Bengal, India, along with arsenic safe control village, Akna in Hoogli district, West Bengal, India. It is found that arsenic is deposited highly in blood, urine and faeces. Agricultural field is contaminated through cattle urine, hair, faeces, cow dung cakes and farmyard manure. Bioconcentration factor and biotransfer factor are two important biomarkers to assess the subclinical toxicity in cattle, as they do not exhibit clinical manifestation like human beings.

Effect of Pleurotus florida lectin (PFL) on arsenic-induced activities of splenocytes in rat.

The present study was undertaken to investigate the protective effect of Pleurotus florida lectin (PFL) against arsenic-induced cytotoxicity and oxidative damages in freshly isolated splenocytes of rodents. Our finding indicated that arsenic caused reduction in cell adhesion, morphological alterations, cell proliferation, nitro blue tetrazolium (NBT) index, superoxide dismutase (SOD) activity, catalase (CAT) activity and relative mRNA expression of SOD2 in relation to housekeeping gene glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and increased production of nitric oxide (NO), protein carbonyl (PC) and lipid peroxidation levels (LPO) assembled to play key factors for cytotoxicity and oxidative stress. PFL normalized cellular damages and enhanced SOD production pathway relating to gene expression. Further studies are needed to address effective phytochemicals of the edible mushroom and their mechanism.

Dynamics of cytokine/chemokine responses in intestinal CD4+ and CD8+ T Cells during Acute Simian Immunodeficiency Virus Infection.

Loss of intestinal CD4(+) T cells was associated with decreased production of several T-helper 1 (TH1) and TH2 cytokines and increased production of interleukin 17 (IL-17), gamma interferon (IFN-γ), CCL4, and granulocyte-macrophage colony-stimulating factor (GM-CSF) by CD8(+) T cells 21 days after simian immunodeficiency virus (SIV) infection in rhesus macaques. Shifting of mucosal TH1 to TH2 or T-cytotoxic 1 (TC1) to TC2 cytokine profiles was not evident. Additionally, both CD4(+) and CD8(+) T cells showed upregulation of macrophage migration inhibition factor (MIF) and basic fibroblast growth factor (FGF-basic) cytokines that have been linked to HIV disease progression.

Interleukin-10 prevents epithelial cell apoptosis by regulating IFNγ and TNFα expression in rhesus macaque colon explants.

Interleukin-10 (IL-10) is an important immunomodulatory cytokine that plays an obligate role in regulating inflammatory responses. Here we demonstrated the role of IL-10 in regulating crypts length and breadth as well as maintaining the survival of epithelial cells using rhesus colon explant cultures. Anti-IL-10 antibody treatment of colon explant cultures induced increased production of inflammatory cytokines/molecules like IFNγ, TNFα, CD107a and perforin as well as increased epithelial cell apoptosis compared to media controls tested. Our results suggest that IL-10 plays a crucial role in maintaining mucosal homeostasis by regulating mucosal IFNγ and TNFα cytokine production.

Evidence of antiapoptotic properties of Pleurotus florida lectin against chronic arsenic toxicity in renal cells of rats.

Chronic arsenic exposure results in toxicity in humans and causes many toxicologic manifestations. Apoptosis was measured by cell adhesion, morphologic alterations, cell proliferation, terminal deoxyuridine triphosphate nick-end labeling (TUNEL), and caspase-3/CPP32 fluorometric protease assay. Results of the present study suggested that arsenic administration in rats caused apoptosis by elevating morphologic alterations, TUNEL-positive nuclei, caspase-3 activity, and DNA damage and by reducing cell adhesion and cell proliferation in a time-dependent manner. The apoptosis in renal cells of arsenic-exposed rats reverted to normal values after coadministration of mushroom lectin. This study provided significant evidence that Pleurotus florida lectin has an antiapoptotic property by protecting from arsenic-induced toxicity. The beneficial effect of Pleurotus florida lectin was proportional to its duration of exposure. This finding might be of therapeutic benefit in people suffering from chronic exposure to arsenic from natural sources, a global problem that is especially relevant to millions of people on the Indian subcontinent.

Metabolic adaptations to arsenic-induced oxidative stress in male wistar rats.

The present study was planned to investigate the effect of arsenic in rats on several biochemical indices of oxidative stress. Rats were exposed to arsenite in drinking water for upto 12 weeks. Chronic exposure to arsenic for a period of 12 weeks significantly (p < 0.05) increased arsenic burden in blood, liver, and kidney. Several intrinsic antioxidant defenses were activated after a 4-week exposure to arsenic. Some remained elevated, but others became depressed over a longer exposure period. Alterations in most of the biochemical variables reached statistical significant (p < 0.05). Arsenic significantly (p < 0.01) reduced mRNA expression of the superoxide dismutase 2 (SOD2) gene with respect to the glyceraldehyde 3-phosphate dehydrogenase (GAPDH) gene. These observations indicated that prolong exposure to arsenic causes induction of oxidative stress and biochemical alterations.

Isolation and characterization of intestinal epithelial cells from normal and SIV-infected rhesus macaques.

Impairment of intestinal epithelial barriers contributes to the progression of HIV/SIV infection and leads to generalized HIV-induced immune-cell activation during chronic infection. Rhesus macaques are the major animal model for studying HIV pathogenesis. However, detailed characterization of isolated rhesus epithelial cells (ECs) from intestinal tissues is not well defined. It is also not well documented whether isolated ECs had any other cell contaminants from intestinal tissues during the time of processing that might hamper interpretation of EC preparations or cultures. In this study, we identify and characterize ECs based on flow cytometry and immunohistochemistry methods using various enzymatic and mechanical isolation techniques to enrich ECs from intestinal tissues. This study shows that normal healthy ECs differentially express HLA-DR, CD23, CD27, CD90, CD95 and IL-10R markers. Early apoptosis and upregulation of ICAM-1 and HLA-DR in intestinal ECs are thought to be the key features in SIV mediated enteropathy. The data suggest that intestinal ECs might be playing an important role in mucosal immune responses by regulating the expression of different important regulatory and adhesion molecules and their function.

Chronic arsenicosis in goats with special reference to its exposure, excretion and deposition in an arsenic contaminated zone.

Thirty goats were selected randomly from a village of Nadia district, West Bengal according to the previous reports of human being suffering from chronic arsenicosis. Environmental samples viz. drinking water, rice plants and grass used for goat and biological samples viz. blood, urine, faeces, hair and meat were collected to evaluate the arsenic status. It was found that arsenic concentration in both environmental and biological samples was significantly (p<0.01) higher rather than respective samples on control zone. Bio-concentration factor (BCF) and bio-transfer factor (BTF) are indicated to evaluate the subclinical toxicity in goat as they do not exhibit clinical manifestation like human beings.

Pleurotus florida lectin normalizes duration dependent hepatic oxidative stress responses caused by arsenic in rat.

Natural contamination of arsenic in ground water is a major health problem throughout the World. It is one of the most hazardous substances in the environment known to cause toxicity in multiple organs via oxidative stress. The molecular basis for arsenic toxicity involves direct or indirect damage to protein, lipid and DNA. Various studies have focused on the possible toxic effects of arsenic on membrane components and its correlation with oxidative damage. The present study was aimed to mitigation of arsenic induced hepatic oxidative stress by dietary modulation using of mushroom lectin in rats. Animals were divided into four groups; the first group was used as control. Groups 2, 3 and 4 were arsenic (20 ppm) exposed through drinking water, arsenic exposed plus oral ascorbic acid (25 mg/kg body weight) and arsenic exposed plus oral mushroom lectin (150 mg/kg body weight) respectively for a period of 12 weeks. We observed significant alterations in the antioxidant enzymes, oxidative stress intermediates and SOD(2) gene expression profile on arsenic exposure. These alterations were restored by co-administration of Pleurotus florida lectin which was as potent as standard antioxidant viz. ascorbic acid. The findings of the experiment suggested that P. florida lectin has capability of modulating arsenic mediated toxic effects and could be helpful in ameliorating them.

Sodium arsenite-induced alteration in hepatocyte function of rat with special emphasis on superoxide dismutase expression pathway and its prevention by mushroom lectin.

This study was accomplished to exemplify the possible protective role of ascorbic acid and mushroom lectin against arsenic-induced cytotoxicity and impairment of superoxide dismutase (SOD) production pathway in hepatocytes of rat. Hepatocytes were isolated from rat and treated with sodium arsenite (AS), arsenic plus ascorbic acid (AS + AA) and arsenic plus mushroom lectin (AS + ML). A placebo control was also included. Arsenic treatment resulted in the depletion of cell proliferation, phagocytic activity (nitro blue tetrazolium index) and superoxide dismutase (SOD) activity, relative mRNA expression of superoxide dismutase 2 (SOD(2)) and enhanced production of nitric oxide (NO). Ascorbic acid, a standard antioxidant, could normalize cellular perturbation and SOD production pathway relating to gene expression, whereas partially purified Pleurotus florida lectin (PFL), an edible mushroom containing protein complex, maintained cellular activity and prevented stress by normalizing phagocytic (NBT index) and SOD activities vis-à-vis relative gene expression. It could further defend NO production of hepatocytes. Mushroom lectin strongly prevented sodium arsenite-induced damage of SOD production pathway in hepatocytes, and its effect was also comparable to a standard antioxidant, i.e. ascorbic acid.

Mitigation of arsenic-mediated renal oxidative stress in rat by Pleurotus florida lectin.

Oyster mushroom, Pleurotus florida is regarded as one of the popular food with biopharmaceutical properties. Here, the study aimed to investigate the antioxidative effects of mushroom (Pleurotus florida) lectin against arsenic-induced nephrotoxicity in rats. Animals were divided into four groups; Group 1 was control. Groups 2, 3 and 4 were exposed to arsenic (20 parts per million [ppm] in drinking water), arsenic plus oral supplementation of ascorbic acid (25 mg/kg body weight) and arsenic plus oral supplementation of mushroom lectin (150 mg/kg body weight) respectively. Both ascorbic acid and mushroom lectin prevented the arsenic-mediated growth retardation and normalized the elevated kidney weight. Disrupted activities of superoxide dismutase (SOD) and catalase (CAT) and enhanced lipid peroxidation (LPO), protein carbonyl (PC) and nitric oxides (NO) production in kidney caused by arsenic could also be maintained towards normalcy by supplementation of mushroom lectin and ascorbic acid. These antioxidative effects were exhibited in a time-dependant manner. Further, arsenic-mediated down-regulation of messenger RNA (mRNA) expression of superoxide dismutase 2 (SOD(2)) gene was obstructed by these agents. Thus it was found that mushroom lectin reversed the effect of arsenic-mediated oxidative stress in a time-dependent manner.

Mushroom lectin protects arsenic induced apoptosis in hepatocytes of rodents.

Acute and chronic arsenic exposure result in toxicity both in human and animal beings and cause many hepatic and renal manifestations. The present study stated that mushroom lectin prevents arsenic-induced apoptosis. Apoptosis was measured by morphological alterations, cell proliferation index (CPI), phagocytic activity (nitro blue tetrazolium index; NBT), nitric oxide (NO) production, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, DNA fragmentation and caspase-3 activity. Arsenic exposure at 5 µM in the form of sodium arsenite resulted in significant elevation of deformed cells, NO production, TUNEL stained nuclei of hepatocytes, DNA fragmentation and caspase-3 activity. But the CPI and NBT index were significantly declined in arsenic-treated hepatocytes. The beneficial effect of mushroom lectin at 10 µg/mL, 20 µg/mL and 50 µg/mL) showed increased CPI and phagocytic activity. Mushroom lectin at those concentrations reduced deformed cells, NO production, DNA fragmentation and caspase-3 activity of hepatocytes. But significant better protection was observed in 50 µg/mL mushroom lectin-treated hepatocytes. This finding may be of therapeutic benefit in people suffering from chronic arsenic exposure.

Sodium arsenite mediated immuno-disruption through alteration of transcription profile of cytokines in chicken splenocytes under in vitro system.

Arsenic is a ubiquitously found metalloid that commonly contaminates drinking water and agricultural food. To understand the ecotoxicological effects of arsenic in environment, it is essential to ameliorate the deleterious effects on human and animal health, particularly on the immune response. We investigated the effects of inorganic arsenic (iAs) on the immune response of chicken splenocytes. Both 1 and 10 mM concentrations of sodium arsenite treatment significantly reduced (P<0.001) splenocyte proliferation and phagocytic activity compared to concanavalin A (ConA) stimulated cells at 24, 48 and 72 h of incubation. Nitrous oxide (NO) production was significantly higher (P<0.001) at 24 h and subsequently declined in the higher dose group, while there was a gradual decline from 24 to 72 h in the lower dose group. Comparison of two different concentration of arsenic treatment also revealed time dependent differences. Relative quantification of expression of IFNγ and IL2 revealed that both genes were significantly down regulated (P<0.001) at both concentrations at each time point. iNOS gene was rapidly down regulated in splenocytes at 24 h at the high doses of As treated splenocyte, a gradual decreasing trend at low doses. Down regulation of IL-2 gene expression in response to As was further evidenced by a significant reduction (P<0.001) in the release of IL-2 into the splenocyte culture medium. We suggest that arsenic, a potent immunotoxic agent, modulates non-specific immune responses and alters the expression of cytokines in a dose and time dependent manner.

Effect of chronic intake of arsenic-contaminated water on blood oxidative stress indices in cattle in an arsenic-affected zone.

This study aimed to determine the hemato-biochemical picture and blood oxidative stress in zebu cattle in an arsenic-contaminated zone. Significant decline in total erythrocyte count, packed cell volume, and total plasma protein was observed in cattle of that area in comparison to uncontaminated zone. There was significant elevation of plasma enzyme activities of both alanine aminotransaminase and aspertate aminotransaminase. Increased corpuscular osmotic fragility also proved to be a mechanism for deviation from normal functioning of erythrocytes. Cattle in the affected zone showed a significantly higher arsenic burden in blood. Those animals further showed decreased superoxide dismutase, catalase activities of erythrocytes, and plasma nitrite level, but increased lipid peroxidation and protein carbonyl level. Our finding concluded that cattle of the arsenic-contaminated zone is suffering from a subclinical form of arsenic toxicity, which is proved through altered hemato-biochemical indices and a certain extent of oxidative stress with higher arsenic concentration in blood.