Seeking a position that will enable me to bridge my research skills and knowledge with translational science. An accomplished independent researcher with a strong portfolio of orchestrating success in Biochemistry, Immunology and Molecular Biology.
Background Use of nicotine containing products like electronic cigarettes (e-Cig) and alcohol are... more Background Use of nicotine containing products like electronic cigarettes (e-Cig) and alcohol are associated with mitochondrial membrane depolarization, resulting in the extracellular release of ATP, and mitochondrial DNA (mtDNA), mediating inflammatory responses. While nicotine effects on lungs is well-known, chronic alcohol (ETH) exposure also weakens lung immune responses and cause inflammation. Extracellular ATP (eATP) released by inflammatory/stressed cells stimulate purinergic P2X7 receptors (P2X7r) activation in adjacent cells. We hypothesized that injury caused by alcohol and e-Cig to pulmonary alveolar epithelial cells (hPAEpiC) promote the release of eATP, mtDNA and P2X7r in circulation. This induces a paracrine signaling communication either directly or via EVs to affect brain cells (human brain endothelial cells - hBMVEC). Methods We used a model of primary human pulmonary alveolar epithelial cells (hPAEpiC) and exposed the cells to 100 mM ethanol (ETH), 100 µM acetaldeh...
Journal of Mahatma Gandhi Institute of Medical Sciences, Jul 1, 2017
Context: Formidable disability burden associated with human lymphatic filariasis has compelled WH... more Context: Formidable disability burden associated with human lymphatic filariasis has compelled WHO to campaign for its global elimination programme. Diethyl-carbamazine (DEC) is the mainstay for mass drug administration strategy under this programme. However, till date proper rationale of this almost solitary drug is unknown. Moreover, it has no direct action on the parasite. These limitations call for the search of novel therapeutic options. Cardinal importance in cellular proliferation due to direct involvement in DNA synthesis made folate metabolism, a lucrative therapeutic target. Polyphenols might be a feasible candidate for inhibition of key enzyme of folate metabolism, dihydrofolate reductase (DHFR), since it shares common origin with folate from shikimate pathway. Chalcones are one significant subset of such polyphenols. With this perspective, our research question was that whether synthetic chalcone derivatives can be used as probable antifilarial agent against Brugia malayi by targeting parasitic folate pathway. Aims: 1. To validate possible effect of certain chalcone derivatives against B. malayi microfilariae and its therapeutic safety against peripheral blood mononuclear cell (PBMCs). 2. To explore the apoptotic activity of the proposed compounds by AO-EB staining. 3. To validate B. malayi DHFR enzyme as a plausible target of the drug by both in vivo and in silico studies. Setting: Filarial parasitic model in vitro study. Design: Basic experimental study design. Methods: A series of chalcone compounds was synthesized, characterized and then screened against microfilariae of B. malayi to test their therapeutic potential in terms of loss of parasitic motility. Further, best selected compound was used for determination of inhibitory concentration required and also for the possible lethal dose against human PBMCs. Both in silico molecular docking and further in vitro folate reversal studies were carried out to validate the parasitic target. Possible induction of apoptosis was tested by MTT and cytoplasmic cytochrome c ELISA assay with the proposed drug treated parasite along with suitable controls. Statistical Analysis: Suitable statistical methods for comparative analysis were used. Results: Among 17 chalcone derivatives, M1R showed marked antifilarial effect in micro-molar dosage; also wide difference between IC50and LD50ensured therapeutic safety. Molecular docking through bioinformatics approach with the proposed drug against pre-validated DHFR protein structure of B. malayi showed favourable thermodynamic parameters with lower inhibition constant as compared to positive control. Significant reversal of antifilarial effect of drug mediated DHFR inhibition by addition of folate indicated plausible mechanism of competitive inhibition. Further, significant apoptosis recorded by MTT assay and cytoplasmic cytochrome c ELISA in drug treated parasite against untreated control confirmed a presumable outcome of inhibition of folate metabolism by M1R compound. Conclusion: These results lead us to propose that filarial folate metabolism can be targeted through DHFR with consequent induction of apoptosis for effective therapeutic intervention, using a rationale of structural analogy based competitive inhibition of DHFR by chalcone derivatives.
Journal of Herbs, Spices & Medicinal Plants, Jul 12, 2019
ABSTRACT The present study was designed to explore and validate the antifilarial activity of Murr... more ABSTRACT The present study was designed to explore and validate the antifilarial activity of Murraya koenigii leaf extracts against Brugia malayi parasite. Anti-microfilarial activity of M. koenigii leaves extracted in methanol and ethanol (along with polyphenols depleted fractions) was determined. Ethanolic extract showed higher polyphenols content and anti-microfilarial activity compared to methanolic extract. Polyphenols depletion reduced such activity of ethanolic but not of methanolic extract. Ethanolic extract had lower alkaloids than methanolic extract. Ethanolic extract of M. koenigii leaves caused oxidative stress with concomitant apoptosis along with mitochondrial damage. Abbreviations: DEC: Diethyl carbamazine; DNPH: 2, 4 dinitro phenyl hydrazine reagent; DTNB: 5,5-dithio-bis-(2-nitrobenzoic acid); EB/AO: Ethidium bromide/Acridine orange; MDA: Mass Drug Administration; Mf: Microfilariae; PBS: Phosphate buffered saline; TCA: Trichloroacetic acid; WHO: World Health Organization
A series of Michael adducts of malononitrile and sulfonamide chalcones were synthesized, characte... more A series of Michael adducts of malononitrile and sulfonamide chalcones were synthesized, characterized, and evaluated for their antifilarial activity. Out of 14 compounds, N-(4-(4,4-dicyano-3-p-tolylbutanoyl)phenyl)benzenesulfonamide showed favorable drug-likeness properties with marked antifilarial effects at micro-molar dosages. Apoptosis in Brugia malayi microfilariae was confirmed by EB/AO staining, MTT assay, and cytoplasmic cytochrome c ELISA. Since chalcone and folate synthesis pathways share the same substrate, we hypothesize a structural analogy-based inhibition of folate metabolism by this compound. Molecular docking against a pre-validated BmDHFR protein showed more favorable thermodynamic parameters than a positive control, epicatechin-3-gallate. The compound significantly suppressed the DHFR activity in a parasite extract in vitro. Our hypothesis is also supported by a significant reversal of DHFR inhibition by folate addition, which indicated a plausible mechanism of c...
Tuberculosis (TB) remains a global health problem and the emergence of HIV has further worsened i... more Tuberculosis (TB) remains a global health problem and the emergence of HIV has further worsened it. Long chemotherapy and the emergence of drug-resistance strains of Mycobacterium tuberculosis as well as HIV has aggravated the problem. This demands urgent the need to develop new anti-tuberculosis and antiretrovirals to treat TB and HIV. The lack of diversity in drugs designed using traditional approaches is a major disadvantage and limits the treatment options. Therefore, new technologies and approaches are required to solve the current issues and enhance the production of drugs. Interestingly, fragment-based drug discovery (FBDD) has gained an advantage over high-throughput screenings as FBDD has enabled rapid and efficient progress to develop potent small molecule compounds that specifically bind to the target. Several potent inhibitor compounds of various targets have been developed using FBDD approach and some of them are under progression to clinical trials. In this review, we ...
Brugia malayi Abundant larval transcript-2 (BmALT-2) is most potential prophylactic vaccine candi... more Brugia malayi Abundant larval transcript-2 (BmALT-2) is most potential prophylactic vaccine candidate. In order to increase the protection efcacy of BmALT-2, Monophosphory Lipid A (MPLA), as adjuvant, a detoxied derivative of lipopolysaccharide (LPS) known to promote Th-1 responses, was used in this study. Moreover to determine the percentage of protection obtained following a challenge infection with B. malayi L3 larvae in immunized Mastomys. This study used, 6-8 weeks aged healthy Mastomys (n=5-7/group), immunized intramuscularly with 50 μg of rBmALT-2 antigen either with MPLA or Alum as adjuvant and the control groups received MPLA or Alum only. The protective immunity elicited in the Mastomys was checked by in vitro antibody-dependent cellular cytotoxicity (ADCC) and in vivo micropore chamber assay. The humoral and cellular immune responses were also analyzed. Our results demonstrate, high antibody response in all immunized group compared to control group. We observed increase...
The emergence of drug-resistant mycobacteria, including Mycobacterium tuberculosis (Mtb) and non-... more The emergence of drug-resistant mycobacteria, including Mycobacterium tuberculosis (Mtb) and non-tuberculous mycobacteria (NTM), poses an increasing global threat that urgently demands the development of new potent anti-mycobacterial drugs. One of the approaches toward the identification of new drugs is fragment-based drug discovery (FBDD), which is the most ingenious among other drug discovery models, such as structure-based drug design (SBDD) and high-throughput screening. Specialized techniques, such as X-ray crystallography, nuclear magnetic resonance spectroscopy, and many others, are part of the drug discovery approach to combat the Mtb and NTM global menaces. Moreover, the primary drawbacks of traditional methods, such as the limited measurement of biomolecular toxicity and uncertain bioavailability evaluation, are successfully overcome by the FBDD approach. The current review focuses on the recognition of fragment-based drug discovery as a popular approach using virtual, com...
PURPOSE Oxidative stress is an essential component of innate response against microbes. The oxida... more PURPOSE Oxidative stress is an essential component of innate response against microbes. The oxidative impact has a very subtle connection with apoptosis. Our previous work indicated presumptive evidence of apoptosis by the chalcone derivatives against the human lymphatic filarial parasite. Evidence suggests the involvement of glutathione-S-transferase (GST) in the mechanism of action of chalcone drugs. In the present study, we explored the implications of redox status in apoptosis of the parasite by this drug. RESULTS Treatment with the representative drug, 4t, significantly decreased GSH level and increased GST activity in the Brugia malayi microfilariae (Mf) in comparison to Mf without 4t treatment. Drug-induced loss of motility of the parasites was reversed by the treatment with GSH (41%) and NAC (19%). A significant fall in rGST activity was observed due to drug addition, which could be reversed by the addition of GSH co-substrate, but not with the re-addition of rGST, indicating a vital role of GSH. In silico study demonstrated a favorable drug-GST enzyme interaction. Oxidative stress was reflected by increased protein carbonylation and intracellular reactive oxygen species level, in the drug-treated parasite. Mitochondrial oxygen consumption was reduced by the drug, which was reversed on the addition of GSH. Mitochondrial dysfunction was confirmed by MTT and cytochrome c assay. Apoptosis was confirmed by the inhibition in PARP activity. CONCLUSION We conclude that the depletion of GSH by chalcone with concomitant mitochondrial dysfunction revealed a novel rationale of apoptosis in the parasite. Such a mechanism might have wide therapeutic implications.
Human lymphatic filariae have evolved numerous immune evasion strategies to secure their long-ter... more Human lymphatic filariae have evolved numerous immune evasion strategies to secure their long-term survival in a host. These strategies include regulation of pattern recognition receptors, mimicry with host glycans and immune molecules, manipulation of innate and adaptive immune cells, induction of apoptosis in effector immune cells, and neutralization of free radicals. This creates an anti-inflammatory and immunoregulatory milieu in the host: a modified Th2 immune response. Therefore, targeting filarial immunomodulators and manipulating the filariae-driven immune system against the filariae can be a potential therapeutic and prophylactic strategy. Filariae-derived immunosuppression can also be exploited to treat other inflammatory diseases and immunopathologic states of parasitic diseases, such as cerebral malaria, and to prevent leishmaniasis. This paper reviews immunomodulatory mechanisms acquired by these filariae for their own survival and their potential application in the dev...
Encouraged by our earlier results of promising therapeutic effect of filarial recombinant protein... more Encouraged by our earlier results of promising therapeutic effect of filarial recombinant proteins BmALT2, BmCys and WbL2 individually in the mouse model of acute ulcerative colitis, in this study, these proteins have been explored individually and in different combinations for their therapeutic potential in dextran sulphate sodium (DSS)‐induced chronic colitis mice. These mice, treated with filarial proteins, showed reduced disease parameters including body weight loss, disease activity index, macroscopic and histopathological scores of colon and myeloperoxidase activity in colonic mucosa. Among various treatment schemes, rBmALT2 + rBmCys which showed most pronounced therapeutic implication was found to downregulate the mRNA expressions of IFN‐γ and TNF‐α and upregulate IL‐10 and TGF‐β expression in the splenocytes. Also, increase in level of IgG1 and IgG2a isotypes in the sera of rBmALT2 + rBmCys‐treated colitis mice was noted. Activated NF‐κB level was found to be reduced in the colon of treated colitis mice compared to untreated one. In conclusion, filarial proteins in combination have been shown to improve the clinicopathologic status of chronic colitis through suppression of pro‐inflammatory immune response most possibly in NF‐κB‐dependent manner. We propose this therapeutic strategy to be tested further to be considered as an effective option in chronic colitis.
Diethyl carbamazine (DEC) is being used as a sole drug to treat the lymphatic filariasis, althoug... more Diethyl carbamazine (DEC) is being used as a sole drug to treat the lymphatic filariasis, although encountered with many limitations. Importantly, DEC works with putative host immunomodulating activities without any direct antifilarial effect. This study aimed to assess the possible modulatory effect on host immune system by sulfonamide chalcone compound, having direct antifilarial activity. The immunomodulatory activity of DEC and/or chalcone compound, 4t on mice peritoneal exudate cells (PECs) was analyzed initially in vitro. This was followed by the study of in vivo effect of these test agents in the parasitaemic BALB/c mice induced by Brugia malayi microfilariae. Cytokine profile and iNOS induction were measured from PECs of mice. 4t compound showed anti-inflammatory activity in vivo in contrast to DEC. Further 4t was found to increase anti-inflammatory and regulatory cytokines, IL-10 and TGF-β gene expression with down regulation of pro-inflammatory cytokines TNF-α and IFN-γ and iNOS in mice PECs in in vitro. In conclusion, chalcones having direct antifilarial effect also upsurges anti-inflammatory host immune response. Therefore, the results might be envisaged as 4t to be a better alternative to DEC in the chronic case of lymphatic filariasis.
Lymphatic filariasis (LF) is a mosquito-transmitted tropical neglected parasitic infection that c... more Lymphatic filariasis (LF) is a mosquito-transmitted tropical neglected parasitic infection that currently affects over 120 million people around the world and another 856 million people are at risk of acquiring the infection. Mass Drug Administration (MDA) spearheaded by the World Health Organization is the only current strategy to control this infection in endemic areas. In this study, we performed an epidemiological survey in select regions in the southern parts of India to determine the current status of LF infection in subjects. Night blood samples were collected from 916 subjects after proper consent and were screened for the presence of circulating microfilariae of Wuchereria bancrofti in their peripheral blood. Our results showed the presence of 51 (5.56%) cases of human LF infection in the surveyed areas including new cases for LF, which were not recorded previously. Given the presence of new cases of LF infections, we trapped mosquitoes from these regions and screened for the presence of W. bancrofti L3 specific Ssp1 DNA repeat sequences by PCR. Our results confirmed the presence of LF infection in the mosquitoes collected from six out of nine districts that we surveyed. These findings confirm active transmission of LF infection in all of the areas that we surveyed, despite several years of MDA treatment. The findings in this study suggest potential reemergence of LF infection in most of the areas we surveyed and warrants for a more stringent strategy for controlling LF in these endemic areas.
Helminthic infections lead to the release of various molecules which play an important role in mo... more Helminthic infections lead to the release of various molecules which play an important role in modulation of the host immune system. Such filarial proteins with immunomodulatory potential can be used for therapeutic purpose in inflammatory and immune mediated diseases. In the present study, we have explored the prophylactic effect of filarial SXP-RAL family protein of i.e. rWbL2 protein in DSS induced inflammatory ulcerative colitis in a mouse model. Prior treatment of rWbL2, followed by induction of colitis, showed significantly reduced disease severity as indicated by the decreased disease manifestations and improved macroscopic and microscopic inflammation. This preventive effect was found to be associated with increased release of anti-inflammatory cytokine IL-10 and decreased release of proinflammatory cytokines IFN-γ, TNF-α, IL-6 and IL-17 by the splenocytes of treated mice. From this study, it can be envisaged that pretreatment with filarial protein, rWbL2, can prevent the establishment of ulcerative colitis in BALB/c mice. The underlying immunological mechanism may involve the up-regulation of Th2 immune response with down-regulation of Th1 response.
Journal of Mahatma Gandhi Institute of Medical Sciences, 2017
Context: Formidable disability burden associated with human lymphatic filariasis has compelled WH... more Context: Formidable disability burden associated with human lymphatic filariasis has compelled WHO to campaign for its global elimination programme. Diethyl-carbamazine (DEC) is the mainstay for mass drug administration strategy under this programme. However, till date proper rationale of this almost solitary drug is unknown. Moreover, it has no direct action on the parasite. These limitations call for the search of novel therapeutic options. Cardinal importance in cellular proliferation due to direct involvement in DNA synthesis made folate metabolism, a lucrative therapeutic target. Polyphenols might be a feasible candidate for inhibition of key enzyme of folate metabolism, dihydrofolate reductase (DHFR), since it shares common origin with folate from shikimate pathway. Chalcones are one significant subset of such polyphenols. With this perspective, our research question was that whether synthetic chalcone derivatives can be used as probable antifilarial agent against Brugia malay...
Background Use of nicotine containing products like electronic cigarettes (e-Cig) and alcohol are... more Background Use of nicotine containing products like electronic cigarettes (e-Cig) and alcohol are associated with mitochondrial membrane depolarization, resulting in the extracellular release of ATP, and mitochondrial DNA (mtDNA), mediating inflammatory responses. While nicotine effects on lungs is well-known, chronic alcohol (ETH) exposure also weakens lung immune responses and cause inflammation. Extracellular ATP (eATP) released by inflammatory/stressed cells stimulate purinergic P2X7 receptors (P2X7r) activation in adjacent cells. We hypothesized that injury caused by alcohol and e-Cig to pulmonary alveolar epithelial cells (hPAEpiC) promote the release of eATP, mtDNA and P2X7r in circulation. This induces a paracrine signaling communication either directly or via EVs to affect brain cells (human brain endothelial cells - hBMVEC). Methods We used a model of primary human pulmonary alveolar epithelial cells (hPAEpiC) and exposed the cells to 100 mM ethanol (ETH), 100 µM acetaldeh...
Journal of Mahatma Gandhi Institute of Medical Sciences, Jul 1, 2017
Context: Formidable disability burden associated with human lymphatic filariasis has compelled WH... more Context: Formidable disability burden associated with human lymphatic filariasis has compelled WHO to campaign for its global elimination programme. Diethyl-carbamazine (DEC) is the mainstay for mass drug administration strategy under this programme. However, till date proper rationale of this almost solitary drug is unknown. Moreover, it has no direct action on the parasite. These limitations call for the search of novel therapeutic options. Cardinal importance in cellular proliferation due to direct involvement in DNA synthesis made folate metabolism, a lucrative therapeutic target. Polyphenols might be a feasible candidate for inhibition of key enzyme of folate metabolism, dihydrofolate reductase (DHFR), since it shares common origin with folate from shikimate pathway. Chalcones are one significant subset of such polyphenols. With this perspective, our research question was that whether synthetic chalcone derivatives can be used as probable antifilarial agent against Brugia malayi by targeting parasitic folate pathway. Aims: 1. To validate possible effect of certain chalcone derivatives against B. malayi microfilariae and its therapeutic safety against peripheral blood mononuclear cell (PBMCs). 2. To explore the apoptotic activity of the proposed compounds by AO-EB staining. 3. To validate B. malayi DHFR enzyme as a plausible target of the drug by both in vivo and in silico studies. Setting: Filarial parasitic model in vitro study. Design: Basic experimental study design. Methods: A series of chalcone compounds was synthesized, characterized and then screened against microfilariae of B. malayi to test their therapeutic potential in terms of loss of parasitic motility. Further, best selected compound was used for determination of inhibitory concentration required and also for the possible lethal dose against human PBMCs. Both in silico molecular docking and further in vitro folate reversal studies were carried out to validate the parasitic target. Possible induction of apoptosis was tested by MTT and cytoplasmic cytochrome c ELISA assay with the proposed drug treated parasite along with suitable controls. Statistical Analysis: Suitable statistical methods for comparative analysis were used. Results: Among 17 chalcone derivatives, M1R showed marked antifilarial effect in micro-molar dosage; also wide difference between IC50and LD50ensured therapeutic safety. Molecular docking through bioinformatics approach with the proposed drug against pre-validated DHFR protein structure of B. malayi showed favourable thermodynamic parameters with lower inhibition constant as compared to positive control. Significant reversal of antifilarial effect of drug mediated DHFR inhibition by addition of folate indicated plausible mechanism of competitive inhibition. Further, significant apoptosis recorded by MTT assay and cytoplasmic cytochrome c ELISA in drug treated parasite against untreated control confirmed a presumable outcome of inhibition of folate metabolism by M1R compound. Conclusion: These results lead us to propose that filarial folate metabolism can be targeted through DHFR with consequent induction of apoptosis for effective therapeutic intervention, using a rationale of structural analogy based competitive inhibition of DHFR by chalcone derivatives.
Journal of Herbs, Spices & Medicinal Plants, Jul 12, 2019
ABSTRACT The present study was designed to explore and validate the antifilarial activity of Murr... more ABSTRACT The present study was designed to explore and validate the antifilarial activity of Murraya koenigii leaf extracts against Brugia malayi parasite. Anti-microfilarial activity of M. koenigii leaves extracted in methanol and ethanol (along with polyphenols depleted fractions) was determined. Ethanolic extract showed higher polyphenols content and anti-microfilarial activity compared to methanolic extract. Polyphenols depletion reduced such activity of ethanolic but not of methanolic extract. Ethanolic extract had lower alkaloids than methanolic extract. Ethanolic extract of M. koenigii leaves caused oxidative stress with concomitant apoptosis along with mitochondrial damage. Abbreviations: DEC: Diethyl carbamazine; DNPH: 2, 4 dinitro phenyl hydrazine reagent; DTNB: 5,5-dithio-bis-(2-nitrobenzoic acid); EB/AO: Ethidium bromide/Acridine orange; MDA: Mass Drug Administration; Mf: Microfilariae; PBS: Phosphate buffered saline; TCA: Trichloroacetic acid; WHO: World Health Organization
A series of Michael adducts of malononitrile and sulfonamide chalcones were synthesized, characte... more A series of Michael adducts of malononitrile and sulfonamide chalcones were synthesized, characterized, and evaluated for their antifilarial activity. Out of 14 compounds, N-(4-(4,4-dicyano-3-p-tolylbutanoyl)phenyl)benzenesulfonamide showed favorable drug-likeness properties with marked antifilarial effects at micro-molar dosages. Apoptosis in Brugia malayi microfilariae was confirmed by EB/AO staining, MTT assay, and cytoplasmic cytochrome c ELISA. Since chalcone and folate synthesis pathways share the same substrate, we hypothesize a structural analogy-based inhibition of folate metabolism by this compound. Molecular docking against a pre-validated BmDHFR protein showed more favorable thermodynamic parameters than a positive control, epicatechin-3-gallate. The compound significantly suppressed the DHFR activity in a parasite extract in vitro. Our hypothesis is also supported by a significant reversal of DHFR inhibition by folate addition, which indicated a plausible mechanism of c...
Tuberculosis (TB) remains a global health problem and the emergence of HIV has further worsened i... more Tuberculosis (TB) remains a global health problem and the emergence of HIV has further worsened it. Long chemotherapy and the emergence of drug-resistance strains of Mycobacterium tuberculosis as well as HIV has aggravated the problem. This demands urgent the need to develop new anti-tuberculosis and antiretrovirals to treat TB and HIV. The lack of diversity in drugs designed using traditional approaches is a major disadvantage and limits the treatment options. Therefore, new technologies and approaches are required to solve the current issues and enhance the production of drugs. Interestingly, fragment-based drug discovery (FBDD) has gained an advantage over high-throughput screenings as FBDD has enabled rapid and efficient progress to develop potent small molecule compounds that specifically bind to the target. Several potent inhibitor compounds of various targets have been developed using FBDD approach and some of them are under progression to clinical trials. In this review, we ...
Brugia malayi Abundant larval transcript-2 (BmALT-2) is most potential prophylactic vaccine candi... more Brugia malayi Abundant larval transcript-2 (BmALT-2) is most potential prophylactic vaccine candidate. In order to increase the protection efcacy of BmALT-2, Monophosphory Lipid A (MPLA), as adjuvant, a detoxied derivative of lipopolysaccharide (LPS) known to promote Th-1 responses, was used in this study. Moreover to determine the percentage of protection obtained following a challenge infection with B. malayi L3 larvae in immunized Mastomys. This study used, 6-8 weeks aged healthy Mastomys (n=5-7/group), immunized intramuscularly with 50 μg of rBmALT-2 antigen either with MPLA or Alum as adjuvant and the control groups received MPLA or Alum only. The protective immunity elicited in the Mastomys was checked by in vitro antibody-dependent cellular cytotoxicity (ADCC) and in vivo micropore chamber assay. The humoral and cellular immune responses were also analyzed. Our results demonstrate, high antibody response in all immunized group compared to control group. We observed increase...
The emergence of drug-resistant mycobacteria, including Mycobacterium tuberculosis (Mtb) and non-... more The emergence of drug-resistant mycobacteria, including Mycobacterium tuberculosis (Mtb) and non-tuberculous mycobacteria (NTM), poses an increasing global threat that urgently demands the development of new potent anti-mycobacterial drugs. One of the approaches toward the identification of new drugs is fragment-based drug discovery (FBDD), which is the most ingenious among other drug discovery models, such as structure-based drug design (SBDD) and high-throughput screening. Specialized techniques, such as X-ray crystallography, nuclear magnetic resonance spectroscopy, and many others, are part of the drug discovery approach to combat the Mtb and NTM global menaces. Moreover, the primary drawbacks of traditional methods, such as the limited measurement of biomolecular toxicity and uncertain bioavailability evaluation, are successfully overcome by the FBDD approach. The current review focuses on the recognition of fragment-based drug discovery as a popular approach using virtual, com...
PURPOSE Oxidative stress is an essential component of innate response against microbes. The oxida... more PURPOSE Oxidative stress is an essential component of innate response against microbes. The oxidative impact has a very subtle connection with apoptosis. Our previous work indicated presumptive evidence of apoptosis by the chalcone derivatives against the human lymphatic filarial parasite. Evidence suggests the involvement of glutathione-S-transferase (GST) in the mechanism of action of chalcone drugs. In the present study, we explored the implications of redox status in apoptosis of the parasite by this drug. RESULTS Treatment with the representative drug, 4t, significantly decreased GSH level and increased GST activity in the Brugia malayi microfilariae (Mf) in comparison to Mf without 4t treatment. Drug-induced loss of motility of the parasites was reversed by the treatment with GSH (41%) and NAC (19%). A significant fall in rGST activity was observed due to drug addition, which could be reversed by the addition of GSH co-substrate, but not with the re-addition of rGST, indicating a vital role of GSH. In silico study demonstrated a favorable drug-GST enzyme interaction. Oxidative stress was reflected by increased protein carbonylation and intracellular reactive oxygen species level, in the drug-treated parasite. Mitochondrial oxygen consumption was reduced by the drug, which was reversed on the addition of GSH. Mitochondrial dysfunction was confirmed by MTT and cytochrome c assay. Apoptosis was confirmed by the inhibition in PARP activity. CONCLUSION We conclude that the depletion of GSH by chalcone with concomitant mitochondrial dysfunction revealed a novel rationale of apoptosis in the parasite. Such a mechanism might have wide therapeutic implications.
Human lymphatic filariae have evolved numerous immune evasion strategies to secure their long-ter... more Human lymphatic filariae have evolved numerous immune evasion strategies to secure their long-term survival in a host. These strategies include regulation of pattern recognition receptors, mimicry with host glycans and immune molecules, manipulation of innate and adaptive immune cells, induction of apoptosis in effector immune cells, and neutralization of free radicals. This creates an anti-inflammatory and immunoregulatory milieu in the host: a modified Th2 immune response. Therefore, targeting filarial immunomodulators and manipulating the filariae-driven immune system against the filariae can be a potential therapeutic and prophylactic strategy. Filariae-derived immunosuppression can also be exploited to treat other inflammatory diseases and immunopathologic states of parasitic diseases, such as cerebral malaria, and to prevent leishmaniasis. This paper reviews immunomodulatory mechanisms acquired by these filariae for their own survival and their potential application in the dev...
Encouraged by our earlier results of promising therapeutic effect of filarial recombinant protein... more Encouraged by our earlier results of promising therapeutic effect of filarial recombinant proteins BmALT2, BmCys and WbL2 individually in the mouse model of acute ulcerative colitis, in this study, these proteins have been explored individually and in different combinations for their therapeutic potential in dextran sulphate sodium (DSS)‐induced chronic colitis mice. These mice, treated with filarial proteins, showed reduced disease parameters including body weight loss, disease activity index, macroscopic and histopathological scores of colon and myeloperoxidase activity in colonic mucosa. Among various treatment schemes, rBmALT2 + rBmCys which showed most pronounced therapeutic implication was found to downregulate the mRNA expressions of IFN‐γ and TNF‐α and upregulate IL‐10 and TGF‐β expression in the splenocytes. Also, increase in level of IgG1 and IgG2a isotypes in the sera of rBmALT2 + rBmCys‐treated colitis mice was noted. Activated NF‐κB level was found to be reduced in the colon of treated colitis mice compared to untreated one. In conclusion, filarial proteins in combination have been shown to improve the clinicopathologic status of chronic colitis through suppression of pro‐inflammatory immune response most possibly in NF‐κB‐dependent manner. We propose this therapeutic strategy to be tested further to be considered as an effective option in chronic colitis.
Diethyl carbamazine (DEC) is being used as a sole drug to treat the lymphatic filariasis, althoug... more Diethyl carbamazine (DEC) is being used as a sole drug to treat the lymphatic filariasis, although encountered with many limitations. Importantly, DEC works with putative host immunomodulating activities without any direct antifilarial effect. This study aimed to assess the possible modulatory effect on host immune system by sulfonamide chalcone compound, having direct antifilarial activity. The immunomodulatory activity of DEC and/or chalcone compound, 4t on mice peritoneal exudate cells (PECs) was analyzed initially in vitro. This was followed by the study of in vivo effect of these test agents in the parasitaemic BALB/c mice induced by Brugia malayi microfilariae. Cytokine profile and iNOS induction were measured from PECs of mice. 4t compound showed anti-inflammatory activity in vivo in contrast to DEC. Further 4t was found to increase anti-inflammatory and regulatory cytokines, IL-10 and TGF-β gene expression with down regulation of pro-inflammatory cytokines TNF-α and IFN-γ and iNOS in mice PECs in in vitro. In conclusion, chalcones having direct antifilarial effect also upsurges anti-inflammatory host immune response. Therefore, the results might be envisaged as 4t to be a better alternative to DEC in the chronic case of lymphatic filariasis.
Lymphatic filariasis (LF) is a mosquito-transmitted tropical neglected parasitic infection that c... more Lymphatic filariasis (LF) is a mosquito-transmitted tropical neglected parasitic infection that currently affects over 120 million people around the world and another 856 million people are at risk of acquiring the infection. Mass Drug Administration (MDA) spearheaded by the World Health Organization is the only current strategy to control this infection in endemic areas. In this study, we performed an epidemiological survey in select regions in the southern parts of India to determine the current status of LF infection in subjects. Night blood samples were collected from 916 subjects after proper consent and were screened for the presence of circulating microfilariae of Wuchereria bancrofti in their peripheral blood. Our results showed the presence of 51 (5.56%) cases of human LF infection in the surveyed areas including new cases for LF, which were not recorded previously. Given the presence of new cases of LF infections, we trapped mosquitoes from these regions and screened for the presence of W. bancrofti L3 specific Ssp1 DNA repeat sequences by PCR. Our results confirmed the presence of LF infection in the mosquitoes collected from six out of nine districts that we surveyed. These findings confirm active transmission of LF infection in all of the areas that we surveyed, despite several years of MDA treatment. The findings in this study suggest potential reemergence of LF infection in most of the areas we surveyed and warrants for a more stringent strategy for controlling LF in these endemic areas.
Helminthic infections lead to the release of various molecules which play an important role in mo... more Helminthic infections lead to the release of various molecules which play an important role in modulation of the host immune system. Such filarial proteins with immunomodulatory potential can be used for therapeutic purpose in inflammatory and immune mediated diseases. In the present study, we have explored the prophylactic effect of filarial SXP-RAL family protein of i.e. rWbL2 protein in DSS induced inflammatory ulcerative colitis in a mouse model. Prior treatment of rWbL2, followed by induction of colitis, showed significantly reduced disease severity as indicated by the decreased disease manifestations and improved macroscopic and microscopic inflammation. This preventive effect was found to be associated with increased release of anti-inflammatory cytokine IL-10 and decreased release of proinflammatory cytokines IFN-γ, TNF-α, IL-6 and IL-17 by the splenocytes of treated mice. From this study, it can be envisaged that pretreatment with filarial protein, rWbL2, can prevent the establishment of ulcerative colitis in BALB/c mice. The underlying immunological mechanism may involve the up-regulation of Th2 immune response with down-regulation of Th1 response.
Journal of Mahatma Gandhi Institute of Medical Sciences, 2017
Context: Formidable disability burden associated with human lymphatic filariasis has compelled WH... more Context: Formidable disability burden associated with human lymphatic filariasis has compelled WHO to campaign for its global elimination programme. Diethyl-carbamazine (DEC) is the mainstay for mass drug administration strategy under this programme. However, till date proper rationale of this almost solitary drug is unknown. Moreover, it has no direct action on the parasite. These limitations call for the search of novel therapeutic options. Cardinal importance in cellular proliferation due to direct involvement in DNA synthesis made folate metabolism, a lucrative therapeutic target. Polyphenols might be a feasible candidate for inhibition of key enzyme of folate metabolism, dihydrofolate reductase (DHFR), since it shares common origin with folate from shikimate pathway. Chalcones are one significant subset of such polyphenols. With this perspective, our research question was that whether synthetic chalcone derivatives can be used as probable antifilarial agent against Brugia malay...
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Papers by Namdev Togre