Dr. Udaykumar Ranga Udaykumar Ranga  
Jawaharlal Nuhru Centre for Advanced Scientific Research
Bangalore, India
US Callaborator: Vinayaka R. Prasad, Ph.D.

Dr. Ranga visited the Einstein AITRP twice, once in 2003 and the other time in 2004 to initiate studies on HIV-associated dementia and its correlation to HIV-1 viral subtype differences. In collaboration with Dr. Vinayaka Prasad at Einstein AITRP, Dr. Ranga and his students examined the effect of a natural single amino acid variation in the Tat protein of clade C of HIV-1 on the transactivation and chemokine properties. This collaboration resulted in the identification of the defective chemokine nature of clade C Tat protein and led to the proposition that this variation might contribute to the underrepresentation of HIV-associated dementia in India. This hypothesis garnered much experimental support subsequently by various research groups including that of Dr. Prasad's. Dr. Pankaj Serh's laboratory at National Brain Research Centre, New Delhi, India took cue from the hypothesis and investigated into the cytotoxic properties of Tat proteins of viral clades on primary human neurons. Dr. Seth's laboratory has active research collaborations with Dr. Ranga and investigating the neuropathogenic properties of HIV full time. Dr. Sunit Singh at Centre for Cellular and Molecular Biology, Hyderabad, India is investigating on how Tat proteins derived from different viral clades could influence miRNA expression pattern of Brain microvascular endothelial cells. He has been collaborating with Dr. Joan Berman's laboratory and with Dr. Ranga in this project. This hypothesis also resulted in active collaboration between Dr. Ranga's group and Dr. Dr. Keiko Ozato at National Institute of Child Health and Human Development, National Institutes of Health. This collaboration exploring the influence of Tat on dendritic cell differentiation secured two different I-to-I projects from NIH in 2007 and 2008. A graduate student from his research team at JNCASR, Nagadenahalli B Siddappa, also visited Dr. Prasad's laboratory and made important observations on Tat-induced cytokine/chemokine gene expression from host cells and a correlation of this to viral clade differences. Dr. Siddappa is presently working as a post-doctoral fellow at Dana-Farber Cancer Institute, Harvard Medical School with Dr. Ruth M. Ruprecht. He is likely to be recruited as one of the first faculty members of a new HIV vaccine research Centre which will be commissioned between the ICGEB, New Delhi, India and Emory University School of Medicine, Atlanta, USA. A second student from Dr. Ranga's laboratory, Dr. Prashata Kumar Dash, visited Dr. Prasad's laboratory and studied the biological properties of the molecular clones of a subject with HIV-associated dementia. Most of the above work was published in several good quality journals. Dr. Dash is presently working as a post-doctoral fellow at the University of Nebraska Medical Center with Dr. Howard E. Gendelman. The training meted out to the students through the AITRP helped them immensely and today both of them have high quality publications from their respective laboratories.

Dr. Ranga's students who visited Einstein AITRP for training:
  1. Nagadenahalli Byrareddy Siddappa, 2003-2004
  2. Prasanta Kumar Dash, 2007-2008
Publications through AITRP-supported collaboration
  1. Rao VR, Sas A, Eugenin EA, Siddappa NB, Nelson HB, Berman JW, Ranga U, Tyor WR, Prasad VR. HIV- 1 clade-specific differences in the induction of neuropathogenesis. J Neuroscience 2008; 28: 10010-6.
  2. Dash PK*, Siddappa NB*, Mangaiarkarasi A, Roshan PB, Aruna VM, Mahadevan A, Shankar SK, Satishchandra P, Prasad VR and Ranga U. Expanded coreceptor use of HIV-1 subtype-C molecular clones isolated from an Indian demented subject: implications for HIV-1 associated dementia. Retrovirology 2008, 5:25 (* Equal contribution).
  3. Siddappa NB, Venkatramanan M, Venkatesh P, Janki MV, Jayasuryan N, Desai A, Ravi V, Ranga U. Transactivation and signaling functions of Tat are not correlated: biological and immunological characterization of HIV-1 subtype-C Tat protein. Retrovirology 2006; 3:53.
  4. Ranga U, Shankarappa R*, Siddappa NB*, Ramakrishna L, Nagendran R, Mahalingam M, Mahadevan A, Jayasuryan N, Satishchandra P, Shankar SK, Prasad VR. Tat protein of human immunodeficiency virus type 1 subtype C strains is a defective chemokine. J Virol 2004: 78: 2586-90 (*Equal contribution).
Joint Grants with Einstein Investigators
  1. Current Support
    R01MH083579-02 (Prasad), 05/12/2008 - 04/30/2013
    Dissecting the Role of HIV-1 Tat and the Chemokine Axis in Subtype-Specificity of HAD
  2. Completed Support
    R21 MH075636-03 (Prasad), 09/01/2005 - 08/31/2007
    Delineating Viral Determinants of HAD using SCID Mice

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