Editorial Board of International Journal of Virology and Diseases
Dr Shashi Kant Tiwari
Department of Pediatrics, University of California, San Diego (UCSD), School of Medicine, Biomedical Research Facility II (Health Sciences)
Biography & Research Interest
AREA OF SPECIALIZATION:
Cellular and Molecular Neurotoxicology, Stem Cell Biology and regenerative medicine, RNA Biology
Normal mammalian brain development and maintenance is orchestrated by intricate interaction of genetic and environmental factors. Neurogenesis plays important role during normal brain development which involves a balance between Neural Stem Cell (NSCs) proliferation, their migration to different parts of the brain followed by differentiation to neurons, astrocytes and oligodendrocytes. For optimum brain development newly generated neurons move along precise pathways from their points of origin to their assigned locations, establish synapses with each other, and communicate via these synapses. My research examines how NSCs respond to the cues such as environmental toxicants, drugs, pathogens (HIV) and various neurodegenerative conditions such as Alzheimer’s and Parkinson’s diseases.
The effects of environmental toxicants during brain development: We found that exposure of environmental toxicants (pesticides and xenoestrogens) during prenatal and postnatal periods in rodents, modulating the factors that regulate and maintain the dynamic balance between various steps of neurogenesis. In addition, impairment of autophagy processes during brain development due to exposure of toxicants leads to neurodegeneration and cognitive dysfunction. Further, we also used neural stem cells as an alternate in vitro model to assess the neurotoxic potential of these environmental contaminants.
Role of neural stem cells during brain development: My studies of neurogenesis in the developing brain focus on the impact of maternal healthiness or illness on fetal brain development. My prior study in rats shown that exposure of toxicants during early pregnancy can alter stem cell activity in the developing fetal brain. This leads to subtle changes and caused cognitive dysfunction. Prior epidemiological studies have also illustrated that infections and allergies during pregnancy may increase the risk of neurological disorders in the child. Our ongoing research focuses on the effects of combined antiretroviral therapy (cART) mediated cognitive dysfunction in both maternal illness and their impact on fetal brain development in humanized mice.
Role of neural stem cells in the adult neurogenesis: My studies of neural stem cells in the adult focus on the areas such as hippocampus and sub-ventricular zone, where neurogenesis naturally continues throughout life. We have found that nanotized curcumin and an anti-epileptic drug enhances the pool of endogenous NSCs and activating signals that instruct these stem cells to generate new neurons during neurodegenerative conditions. Thus, my goal is to identify the novel compounds or determine if manipulating these signals might boost neurogenesis and enhances stem cell mediated CNS repair in neurological disorders.
Application of stem cells to study CNS injury and diseases: By using information gained from studying NSCs during developing and adult stages, we have been now able to modernize the conditions of neurogenesis in the Petri-dish. By using human embryonic stem cells (hESC) to generate several types of human cells such as microglia, neurons and 3D neural construct (mini-brain) in the Petri-dish for study of neurodevelopmental disease, injury (HIV mediated neuronal injury), or aging-related disorders such as Parkinson’s or Alzheimer’s disease and drug development.
Role of epigenetic factors in neurological disorders using stem cell biology: Epigenetic mechanisms involved in brain development and neuronal differentiation, as well as in more dynamic processes related to cognitive functions. Epigenetic regulation controls the expression of genes through various levels such as regulation of transcription by direct modification of DNA and histone as well as translation by interaction with mRNA. We are currently studying about the modulation of major epigenetic mechanisms such as DNA methylation and DNA demethylation, chromatin remodeling and noncoding RNAs, as well as the involvement of these mechanisms during HIV infection and its consequences brain development in both in vivo and in vitro (hESC derived neural construct) conditions.
MEMBERS OF INTERNATIONAL / NATIONAL SOCIETIES:
➢ International Brain Research Organization (IBRO)
➢ Indian Academy of Neurosciences (IAN)
➢ International society for Neurochemistry (ISN)
➢ Asia Pacific Society for Neurochemistry (APSN)
➢ Society for Free Radical Research (SFRR) India
➢ Qualified All India CSIR/UGC- JRF fellowship (Dec. 2008)
➢ Qualified All India Graduate Aptitude Test for Engineering in Life Science GATE-2008 (Percentile Score- 91.28)
➢ Qualified All India Examination for the post of Post-Graduate Teacher (BIOTECHNOLOGY) in Kendriya Vidyalya Sangathan (KVS) for year 2007-08 & 2008-09
➢ Qualified All India Agricultural Scientists Recruitment Board ICAR/ARS – NET (2009)
➢ Qualified All India Agricultural Scientists Recruitment Board ICAR/ARS – NET (2010)
1. Young Scientist Award: Received INSA medal for young scientist-2015 in the Health Sciences.
2. Received “Jyotsnamoyee-Raghunath Bhattacharya Prize” in 32nd Annual Conference of Indian Academy of Neurosciences during 1st -3rd November-2014 for “Best Paper Award” for the paper “Curcumin loaded nanoparticles potently induce adult neurogenesis and reverse cognitive deficits in Alzheimer’s disease model via canonical Wnt/β-catenin pathway”. ACS Nano. 2014 Jan 28; 8(1):76-103.
3. Received “Travel Award Fellowship” from International Society for Neurochemistry to attend 23rd Biennial Meeting of International Society for Neurochemistry and European Society for Neurochemistry (ISN-ESN) at, Athens, Greece during August 28 to September 1, 2011.
4. “The Tokuji Ikenaka Prize” for best APSN Poster Presentation in The 10th Biennial Meeting of the Asia Pacific Society for Neurochemistry (APSN) at Phuket, Thailand during 17-20th October 2010.
5. Received “Travel Award Fellowship” from Asia Pacific Society for Neurochemistry (APSN) to attend the ISN/APSN School held in Bangkok during 11-15th October 2010 and The 10th Biennial Meeting of the Asia Pacific Society for Neurochemistry (APSN) at Phuket, Thailand during 17-20th October 2010.
6. Received “Senior Research Fellowship” from University Grant Commission (UGC), New Delhi-India during September 2011-September 2014
7. Received “Junior Research Fellowship” from University Grant Commission (UGC), New Delhi-India during September 2009-September 2011.
8. Received Gold medal in B.Sc. (Biotechnology) 2004.