Neelima Sharma

Deltamethrin induced an apoptogenic signalling pathway in murine thymocytes : exploring the molecular mechanism.

Deltamethrin (DLM) is a well‐known pyrethroid insecticide; however, the immunotoxic effects of DLM on the mammalian system and its mechanism is still unclear. This study has been designed to first observe the binding affinity of DLM to immune cell receptors and its effects on the immune system. The docking score revealed that DLM has a strong binding affinity towards the CD4 and CD8 receptors. DLM induces apoptosis in murine thymocytes in a concentration‐dependent manner. The ear\ly markers of apoptosis such as enhanced reactive oxygen species (ROS) and caspase‐3 activation are evident as early as 1 h by 25 and 50 μM DLM. Glutathione (GSH) depletion has also been observed at 1 h by 50 μM DLM concentration. In cell‐cycle studies using flow cytometry, the fraction of hypodiploid cells has gradually increased with all the concentrations of DLM at 18 h. The Annexin V binding assay measures the effect of DLM on apoptotic and necrotic cells. The apoptotic cells raised from 18.6% to 35.21% (10–50 μM DLM) at 18 h. N‐acetyl cysteine (NAC) effectively reduced the percentage of apoptotic cells which is increased by DLM. In contrast, buthionine sulfoximine (BSO) caused an elevation in the percentage of apoptotic cells. These results demonstrate that caspase activation, ROS activation and GSH act as critical mediators in a DLM‐induced apoptogenic signalling pathway in murine thymocytes. In the presence of caspase inhibitor, the percentage of apoptotic cells is partially decreased. Thus, there may be the possibility of some other caspase‐independent pathways in DLM‐induced apoptosis. Copyright

Deltamethrin-induced oxidative stress and mitochondrial caspase-dependent signaling pathways in murine splenocytes

Deltamethrin (DLM) is a well‐known pyrethroid insecticide used extensively in pest control. Exposure to DLM has been demonstrated to cause apoptosis in various cells. However, the immunotoxic effects of DLM on mammalian system and its mechanism is still an open question to be explored. To explore these effects, this study has been designed to first observe the interactions of DLM to immune cell receptors and its effects on the immune system. The docking score revealed that DLM has strong binding affinity toward the CD45 and CD28 receptors. In vitro study revealed that DLM induces apoptosis in murine splenocytes in a concentration‐dependent manner. The earliest markers of apoptosis such as enhanced reactive oxygen species and caspase 3 activation are evident as early as 1 h by 25 and 50 µM DLM. Western blot analysis demonstrated that p38 MAP kinase and Bax expression is increased in a concentration‐dependent manner, whereas Bcl 2 expression is significantly reduced after 3 h of DLM treatment. Glutathione depletion has been also observed at 3 and 6 h by 25 and 50 µM concentration of DLM. Flow cytometry results imply that the fraction of hypodiploid cells has gradually increased with all the concentrations of DLM at 18 h. N‐acetyl cysteine effectively reduces the percentage of apoptotic cells, which is increased by DLM. In contrast, buthionine sulfoxamine causes an elevation in the percentage of apoptotic cells. Phenotyping data imply the effect of DLM toxicity in murine splenocytes. In brief, the study demonstrates that DLM causes apoptosis through its interaction with CD45 and CD28 receptors, leading to oxidative stress and activation of the mitochondrial caspase‐dependent pathways which ultimately affects the immune functions. This study provides mechanistic information by which DLM causes toxicity in murine splenocytes.

Immunomodulatory role of piperine in deltamethrin induced thymic apoptosis and altered immune functions.

Deltamethrin (DLM), a well-known pyrethroid insecticide, is a potent immunotoxicant. In rodents, it is primarily characterized by marked thymic apoptosis. Mechanism of DLM induced thymic apoptosis in primary murine thymocytes has been recently explored. Oxidative stress and activation of caspase dependent pathways appear to be involved in the DLM induced thymic injury. Thus, for the amelioration of its effect, this study has been designed to first observe the binding affinity of piperine to immune cell receptors and its protective effects on the DLM induced immunotoxicity under in vitro condition. The docking results demonstrated that piperine has good binding affinity towards CD4 and CD8 receptors. In vitro study results have shown that piperine (1, 10 and 50 μg/ml) increased cell viability in a concentration dependent manner. The early activated markers of apoptosis such as enhanced reactive oxygen species (ROS) and caspase-3 activation by DLM was significantly reduced by piperine treatment. GSH depletion induced by DLM has been also restored by piperine treatment. At 18 h, all concentration of piperine (1, 10 and 50 μg/ml) significantly ameliorated the DLM induced apoptosis. Further, DLM induced phenotypic changes were mitigated by the piperine. In addition, piperine also restored the cytokine levels, which were suppressed by DLM treatment. These findings strongly indicate the anti-oxidative, anti-apoptotic and chemo-protective ability of piperine in the DLM induced thymic apoptosis.

Comparative efficacy of piperine and curcumin in deltamethrin induced splenic apoptosis and altered immune functions.

Deltamethrin (DLM) being a potent immunotoxicant affects both humoral and cell mediated immunity. Thus, for the amelioration of its effects, two different bioactive herbal extracts piperine and curcumin are evaluated and their efficacy has been compared. The docking results demonstrated that curcumin has good binding affinity towards CD28 and CD45 receptors as compared to piperine but in vitro studies revealed that piperine is more effective. DLM induced apoptotic markers such as oxidative stress and caspase 3 have been attenuated more significantly by piperine as compared to curcumin. Phenotypic and cytokine changes have also been mitigated best with piperine. Thus, these findings strongly demonstrate that piperine displays the more anti-oxidative, anti-apoptotic and chemo-protective properties in the DLM induced splenic apoptosis as compared to curcumin. So, piperine can be considered the drug of choice under immunocompromised conditions.

Mechanism of immunotoxicological effects of tributyltin chloride on murine thymocytes

Tributyltin-chloride, a well-known organotin compound, is a widespread environmental toxicant. The immunotoxic effects of tributyltin-chloride on mammalian system and its mechanism is still unclear. This study is designed to explore the mode of action of tributyltin-induced apoptosis and other parallel apoptotic pathways in murine thymocytes. The earliest response in oxidative stress followed by mitochondrial membrane depolarization and caspase-3 activation has been observed. Pre-treatment with N-acetyl cysteine and buthionine sulfoximine effectively inhibited the tributyltin-induced apoptotic DNA and elevated the sub G1 population, respectively. Caspase inhibitors pretreatment prevent tributyltin-induced apoptosis. Western blot and flow cytometry indicate no translocation of apoptosis-inducing factor and endonuclease G in the nuclear fraction from mitochondria. Intracellular Ca2+ levels are significantly raised by tributyltin chloride. These results clearly demonstrate caspase-dependent apoptotic pathway and support the role of oxidative stress, mitochondrial membrane depolarization, caspase-3 activation, and calcium during tributyltin-chloride (TBTC)-induced thymic apoptosis.

An insight into deltamethrin induced apoptotic calcium, p53 and oxidative stress signalling pathways

Deltamethrin (DLM), a type 2 synthetic pyrethroid insecticide, is widely used in home and agricultural pest control. Humans are exposed to DLM by various modes like air, water, vegetables, etc. at low concentrations. DLM has been considered as safe for humans at low concentrations. At present, its exposure has been increased due to restriction on the sale of organophosphate insecticides. Increasing use of DLM products arise the attention towards its toxicity. It has been demonstrated that DLM at high concentration cause apoptosis in the mammalian cells. However, the mechanism of DLM mediated apoptotic signaling pathways are still an open question to be explored. In the present investigation, various pathways by which DLM induces chaos to different normal cellular activities have been compiled. Possibilities of DLM induced other apoptotic signalling pathways have also been discussed which could be considered for the future studies for better understanding of its mechanism of toxicity. This review provides the detailed study of all the existing and possible apoptogenic signalling pathways induced by DLM which could be helpful for the development of various antidotes for its toxicity.

Mechanism of immunoprotective effects of curcumin in DLM-induced thymic apoptosis and altered immune function: an in silico and in vitro study

Abstract Curcumin, a main component of Curcuma Longa Linn, is a plant polyphenol used as an immune-enhancer in the Indian system of traditional medicine. However, its underlying mechanism of immune-protection remains unknown. The present study is designed to delineate the role of curcumin in deltamethrin (DLM)-induced thymocyte apoptosis and altered immune functions. In silico studies revealed that curcumin has a strong binding affinity toward CD4 and CD8 receptors. DLM (25 µM) induces thymocytes apoptosis through oxidative stress and caspase-dependent pathways. Various concentrations of curcumin (1, 10 and 50 µg/ml), when added along with DLM, caused a concentration- and time-related amelioration in apoptogenic signaling pathways induced by DLM. Inhibition of DLM-induced reactive oxygen species production, replenishment of glutathione and suppression of caspase activities by curcumin may thus be responsible for the suppression of downstream cascade of events, i.e. apoptosis, phenotypic changes and altered cytokine release. Thus, this study clearly demonstrates that the mechanism of immunoprotection of curcumin in DLM-induced thymic apoptosis includes inhibition of oxidative stress and caspase-dependent pathways underlying apoptosis.

Mechanism of deltamethrin induced thymic and splenic toxicity in mice and its protection by piperine and curcumin: in vivo study

Abstract Deltamethrin (DLM) is a well-known pyrethroid insecticide which is widely used in the agriculture and home pest control due to restriction on the sale of organophosphate. DLM induced apoptosis is well known but its mechanism is still unclear. This study has been designed to find out its mechanism of apoptosis with the help of computational methods along with in vivo methods. The QikProp and ProTox results have shown that DLM has good oral absorption. The docking results reveal that DLM has a strong binding affinity toward the CD4, CD8, CD28 and CD45 receptors. Further, to understand the toxicity of DLM on lymphoid cells, a single dose of DLM (5 mg/kg, oral for seven days) has been administered to male Balb/c mice and cytotoxicity (MTT assay), oxidative stress indicators (glutathione, reactive oxygen species) and apoptotic markers (caspase-3 activity, DNA fragmentation) have been assessed in thymic and splenic single cell suspensions. Lowering of body weight, cellularity and loss in cell viability have been observed in DLM treated mice. The significant increase in ROS and GSH depletion in spleen and thymus, indicate the possible involvement of oxidative stress. The spleen cells appear more susceptible to the adverse effects of DLM than thymus cells. Further, for the amelioration of its effect, two structurally different bioactive herbal extracts, piperine and curcumin have been evaluated and have shown the cytoprotective effect by inhibiting the apoptogenic signaling pathways induced by DLM.

Deltamethrin, a pyrethroid insecticide, could be a promising candidate as an anticancer agent

Cancer is the one of the leading causes of death, whose incidences is increasing day by day. Various types of anticancer agents are used for its treatment, but unfortunately none of them is able to treat the cancer. Thus, the exploration of novel mechanistic pathways of existing molecules may help to develop more effective anticancer agents. Deltamethrin, at low concentration, is a safe pyrethroid insecticide that is widely used in the agriculture and home pest control. Recent in vitro and in vivo studies have shown that the deltamethrin have the potential to induce apoptogenic signaling pathways which plays an important role in the mechanism of anticancer action. Thus, deltamethrin thereof could have the potential to develop as an anticancer agent. Further both in vitro and in vivo evaluation of the therapeutic and toxic effects of this compound is needed for starting of clinical trial.

Oral Vaccine Antigen Induced Immune Response Signalling Pathways: Current and Future Perspectives

Vaccination is the most promising approach to control and prevent the infectious diseases. As most of pathogenic microrganisms gain entry through the mucosal surfaces of host which provide great deal of interest in developing oral vaccines. Despite the success of many vaccines, only little information is available regarding the oral vaccine antigen induced immunogenic signalling pathways. Such information will be helpful to design future vaccines against old and new infectious diseases to reduce the side effects of existing vaccines and increase their efficacy. In this review, the oral vaccine antigen inducing complex signaling pathways of immune system has been discussed. Various stra