Browsing by Author "Smita Yadav"

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Antifilarial efficacy of andrographolide: Ex vivo studies on bovine filarial parasite Setaria cervi
(Elsevier Inc., 2022) Smita Yadav; Faiyaz Ahmad; Sushma Rathaur
Lymphatic filariasis caused by filarial nematode is an important disease leading to considerable morbidity throughout tropical countries. Even after specific elimination programs, the disease continue to spread in endemic countries. Thus newer therapeutic interventions are urgently needed to control the spread. In the present study, we have seen the effect of andrographolide (andro), a diterpenoid lactone from the leaves of Andrographis paniculata on filarial parasite Setaria cervi. There was time and concentration dependent decrease in motility and viability leading to death of parasite after 6 h of the exposure of andro. Andro showed potential antifilarial activity with an IC50 value of 24.80 μM assessed through MTT assay. There was concentration dependent decrease in the antioxidant enzymes activity and increase in proapoptotic markers after 5 h exposure of andro. Further, molecular docking analysis revealed that andro binds with filarial glutathione-S-transferase at glutathione (GSH) binding site and inhibiting enzyme activity competitively. Andro induced oxidative stress mediated apoptosis in parasites as evidenced by increase in the intracellular reactive oxygen species (ROS) and apoptotic markers.Therefore this study suggested that andro could be further explored as a new antifilarial drug. © 2022 Elsevier Inc.
Antifilarial efficacy of green silver nanoparticles synthesized using Andrographis paniculata
(Editions de Sante, 2020) Smita Yadav; Shweta Sharma; Faiyaz Ahmad; Sushma Rathaur
The currently available antifilarial drugs are mostly effective against microfilariae. Antifilarial drugs have disadvantages such as toxicity and the development of resistance due to the continuous use. Therefore alternative drugs are required for the control of disease. At present, nanoparticles are used for developing anti-parasitic therapy for their special properties such as smallest in size, bio-availability, bio-compatibility and penetration capacity into a cell. In the present study green nanoparticles were biosynthesized by using leaf extract of Andrographis paniculata to evaluate its antifilarial efficacy. Biosynthesized nanoparticles were characterized by UV–Vis spectroscopy, FTIR, XRD, SEM, EDAX, TEM, HRTEM, AFM and found to be homogenous with average size of 11 nm. The antifilarial efficacy of green nanoparticles was based on adult filarial parasite motility and viability assay. These green nanoparticles (NPs) were found to have antifilarial activity with LC50 of 11.6 μg/ml against adult female filarial parasites. The green nanoparticles induced oxidative stress as evidenced by elevated ROS production and decline of parasitic GST, GR, TRxR and GSH levels in the parasite. The activation of ced-3 gene, a homolog of mammalian caspase 3, reduced expression of ced-9 and decreased activity of cytochrome c oxidase suggested induction of mitochondrial mediated apoptosis in parasite. These green NPs are more effective than the plant extract. This is the first report where green nanoparticles synthesized from A. paniculata showed antifilarial efficacy against adult filarial parasites. © 2020
Identification and characterization of novel membrane-bound PRL protein tyrosine phosphatases from Setaria cervi, a bovine filarial parasite
(Springer Verlag, 2015) Neetu Singh; Smita Yadav; Sushma Rathaur
A significant amount of protein tyrosine phosphatase (PTP) activity was detected in the detergent-soluble membrane-bound fraction of Setaria cervi, a bovine filarial parasite. The membrane-bound PTP activity was significantly inhibited when the adult parasites were exposed to compounds having antifilarial activity like aspirin and SK7 as well as phenylarsine oxide, a specific PTP inhibitor suggesting that this activity is stress regulated. Further, this enzyme was purified as a single protein of apparently 21 kDa using two different chromatographic techniques. The MALDI-MS/MS analysis of its peptides showed closest match with protein tyrosine phosphatase PRL (Aedes aegypti). This purified enzyme (named as PRL) showed maximum activity at pH 5.5/37 °C and hydrolysed para nitro phenyl phosphate (pNPP) at the highest rate followed by O-P-l-tyrosine and O-P-l-threonine. It showed significant inhibition by specific inhibitors of PTP such as sodium orthovanadate, phenylarsine oxide and ammonium molybdate and was activated by dithiothreitol (DTT). The active site modification studies suggested involvement of cysteine, arginine, histidine and aspartic acid in the catalytic activity of PRL. The activity of S. cervi PRL was also found to be resistant towards the external oxidative stress. Thus, S. cervi PRL could be taken as a potential target for the management of human lymphatic filariasis. © 2015, Springer-Verlag Berlin Heidelberg.
Proteomic Analysis Reveals Differential Protein Expression Induced by Inhibition of Prolyl Oligopeptidase in Filarial Parasites
(Springer, 2022) Mohit Wadhawan; Faiyaz Ahmad; Smita Yadav; Sushma Rathaur
Prolyl oligopeptidase (POP) plays a crucial role in the processing and degradation of neuropeptides and regulates inositol trisphosphate (IP3) signaling in mammals. We have reported that POP inhibition leads to IP3-mediated calcium efflux leading to mitochondrial-mediated apoptosis in the filarial parasite Setaria cervi. This study further elucidates the effect of altered calcium homeostasis on the proteome of filarial parasites. Adult parasites were treated with POP’s specific inhibitor, Z-Pro-prolinal (ZPP), for 7 h. Cytosolic and mitochondrial proteome was analyzed using 2D gel electrophoresis coupled with MALDI-MS/MS. Phosphoproteins were also analyzed in the cytosolic fraction of the parasites. The phosphoprotein analysis revealed 7, and 9 spots in the cytosolic fraction of control and ZPP-treated parasites, respectively. The two identified protein spots in the treated set were found to be involved in G protein signaling. In cytosolic fraction, 109 and 112 protein spots were observed in control and treated parasites, respectively. Of these, 56 upregulated and 32 downregulated protein spots were observed in the treated set. On the other hand, 50 and 47 protein spots were detected in the mitochondrial fraction of control and treated parasites, respectively. Of these spots, 18 upregulated and 12 down-regulated protein spots were found in treated parasites. In silico analysis showed that the identified proteins were involved in energy metabolism, calcium signaling, stress response, and cytoskeleton organization. These findings correlate with our previous results suggesting the important regulatory role of POP in signaling and different metabolic pathways of filarial parasites. © 2022, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
The HSP90 inhibitor 17-AAG induced calcium-mediated apoptosis in filarial parasites
(John Wiley and Sons Inc, 2022) Faiyaz Ahmad; Shweta Sharma; Smita Yadav; Sushma Rathaur
The available antifilarial medications are effective only against the larval stage of the filarial parasite. As a result, there is a pressing need for an adulticidal drug. The development of drugs requires the identification of molecular targets that are critical for parasite life. In this study, we observed the effect of 17-N-allyl-17-demethoxygeldanamycin on the survival of adult filarial parasites. The 17-N-allyl-17-demethoxygeldanamycin (17-AAG) is a derivative of geldanamycin (GA), which is an inhibitor of heat shock protein (HSP)90. It is less toxic as compared to geldanamycin. The motility and viability of the adult filarial parasite Setaria cervi were decreased on exposure to 17-AAG at 2.5 and 5.0 μM/ml concentrations. The 17-AAG treated parasites showed induction of oxidative stress as evidenced by decreased activity of various antioxidant enzymes like glutathione s-transferase, glutathione reductase, thioredoxin reductase, and an increase in ROS production in comparison to control. Oxidative stress may lead to altered calcium homeostasis. Indeed, in 17-AAG treated worms, there was a rise in calcium in the cytosol and mitochondria, as well as a decrease in the ER. We also observed enhanced activity of phospholipase C in the treated parasite, suggesting the opening of calcium channels located on the ER membrane. ER stress is marked by a reduced level of protein disulfide isomerase. Further, 17-AAG treated worms showed an increase in apoptotic marker enzyme activities like calpain, cyt-c, and caspase-3. The 2D-gel electrophoresis technique showed 142 protein spots in the control and 112 spots in the 17-AAG treated parasite. Thus, 17-AAG induced oxidative stress, and altered calcium, and proteostasis of parasites, which led to apoptosis. © 2022 Wiley Periodicals LLC.