To understand mammalian fertilization study structure and function of zona pellucida glycoproteins and development of contraceptive vaccines for wildlife population management. Cytokine mediated regulation of trophoblast proliferation, invasion and differentiation. To characterize anti-HIV compounds from medicinal plants and semi-synthetic sources. Development of neutralizing humanized monoclonal antibodies against flu virus.
Summary of Research:
Role of human zona pellucida (ZP) glycoproteins during fertilization and development of contraceptive vaccines for wildlife population management: Our group has demonstrated that in human more than one family of zona proteins (ZP1, ZP3, ZP4) are involved in binding to the spermatozoa and induction of acrosome reaction. Glycosylation of zona proteins is not critical for their binding to the spermatozoa, however critical for the induction of acrosome reaction. In contrast to O-linked glycosylation of mouse ZP3, N-linked glycosylation of human zona proteins is more relevant for the induction of acrosome reaction. Functional domain of human ZP3 resides in its C-terminus. The role of Gi-protein-coupled receptor, T- and L-type Voltage Operated Calcium Channels, and various kinases in ZP1/ZP3/ZP4 mediated induction of acrosome reaction has been deciphered. The enormous potential of ZP glycoproteins as candidate antigen for contraceptive vaccines has been assessed with curtailment of conception in non-human primates. Taking a cue from these studies, the potential application of ZP based immunocontraceptive vaccine for the management of wildlife population with special reference to street dogs is being investigated. Recently, our group has successfully developed protocol for purification of E. coli-expressed recombinant canine ZP3 without His6-tag and its production in batch-fed fermentor.
Cytokine mediated regulation of trophoblast proliferation, invasion and differentiation: Under physiological conditions, controlled invasion and proliferation of trophoblast cells is critical for the formation of placenta and hence for the establishment of pregnancy. We have been trying to understand the differential role of IL-6 group of cytokines with respect to the activation of downstream signaling and expression of effector molecules for regulating the proliferation and invasion of trophoblastic cells. IL-11, LIF and IL-6 increases the invasion of JEG-3 cells while, only LIF could bring out an increase in proliferation of these cells. IL-11 and IL-6 mainly transduce its signal through activation of STAT3 Tyr705 while, LIF in addition also activates ERK1/2 mediated signaling pathway. Silencing of STAT3 expression led to decrease in IL-11 mediated invasion of JEG-3 cells while, LIF mediated proliferation is regulated by ERK½ activation and not by activation of STAT3 Tyr705. Through cDNA microarray, MMP23B and pappalysin-1 have been identified as critical regulators of trophoblastic cell invasiveness following treatment with IL-11 and LIF, respectively. Our studies also suggest that under physiological conditions, IL-11 might act as potential regulator of invasion by increasing the invasiveness of trophoblastic cells in early pregnancy while by decreasing the invasiveness of extravillous trophoblast cells of late pregnancy. These studies will help in understanding the complexity of the regulatory processes involved in cytokine mediated trophoblast proliferation and invasion and thereby facilitating in the development of new intervention strategies for success in implantation.
Natural compounds from medicinal plants for prevention of HIV infection: To prevent HIV transmission through hetero- or homo-sexual routes, microbicides incorporating anti-HIV compounds have been proposed. In this direction, screening of about 30 plants using in vitro reporter-gene based cell assay systems revealed potent anti-HIV activity of the extracts prepared from 4 plants that act by either inhibition of HIV-1 reverse transcription or protease or integrase activity. Furthermore, in addition to seek compounds that may target viral entry or HIV-1 integrase enzyme, a series of andrographolide derivatives and integric acid derivatives have been synthesized. In vitro evaluation of andrographolide derivatives, have shown very promising anti-HIV activity in vitroat concentrations much lower than the cytotoxic concentrations (TI> 500). The derivatives showed promising anti-HIV activity by binding to V3 loop region of the gp120 protein of HIV.
Antibody engineering for treatment of influenza virus infection: We aim to generate influenza virus heterosubtypic neutralizing monoclonal antibodies (MAbs) for exploring the possibility of passive antibody based treatment for severe influenza infections. In a collaborative project, 49 MAbs have been generated against the pandemic H1N1 and other influenza strains. One high affinity MAb (KD = 2.1±0.4 pM), showing in vitro neutralization of 2009 pandemic H1N1 (IC50 = 0.08 µg/ml), recognizing ‘Sa’ epitope on HA protein has been successfully humanized. The humanized antibody also showed in vitro neutralization of 2009 pandemic flu virus. Further, we have also been able to isolate pandemic as well as seasonal H1N1 specific ScFv from human phage display antibody library.
Pankaj Suman, Nutan, Nachiket Shembekar, Abhinav Shrestha, Sudha Saryu Malhotra, Neha Gupta, Boskey Pancholi, Piyush Chaudhary, Vidisha Minhas, Ashok Saini, Anita Goyala
• Science Academy Medal for Young Scientists, Indian National Science Academy
• Shakuntala Amir Chand Prize for Young Scientists, Indian Council of Medical Research
• Smt Swaran Kanta Dingley Oration Award, Indian Council of Medical Research
• Shanti Swarup Bhatnagar Prize in Medical Sciences, Council of Scientific and Industrial Research
• Dr Nitya Anand Endowment Lecture, Indian National Science Academy
• Population Control and Family Planning Award instituted by Drs Anant and Lata Labhsetwar Charitable Trust, Nagpur and Labhsetwar Foundation, USA
• Founder President Prof. T. C. Anand Kumar Gold Medal, Indian Society for the Study of Reproduction and Fertility
• Ranbaxy Research Award - 2011 in Medical Sciences - Medical Research, Ranbaxy Science Foundation
• Fellow, Indian National Science Academy (FNA), Delhi
• Fellow, Indian Academy of Sciences (FASc), Bangalore, India
• Fellow, The National Academy of Sciences (FNASc), Allahabad, India
• Fellow, National Academy of Medical Sciences (India) (FAMS), Delhi
• Tata Innovation Fellowship, Department of Biotechnology, Government of India