Cytopenias in Disease Using HIV-1 Infection of SCID-hu Mice

Cytopenias are a major risk factor particularly thrombocytopenia in HIV infection, heart disease, and cancer. Hematopoietic abnormalities such as its inhibition leads to, or cause, multiple cytopenias in HIV infected individuals with thrombocytopenia emerging as a major risk factor for morbidity and mortality and even more so in patients also suffering from heart conditions. Thrombocytopenia is also a major risk factor in cancer patients undergoing chemotherapy.

The transcription factors such as STAT5A are involved in stem cell self-renewal that precedes multilineage differentiation of CD34+ progenitor stem cells. The proto-oncogene of myeloproliferative leukemia also known as thrombopoietin (Tpo) receptor proto-oncogene, c-mpl, is known to promote multilineage pluripotent stem cell differentiation of the CD34+ progenitor cells. Both STAT5 and c-mpl are important target genes for control and enhancement of stem cell self-renewal and multilineage differentiation to reduce or prevent cytopenias induced during HIV infection. We have used the severe combined immunodeficient mouse cotransplanted with human fetal thymus and liver tissues (SCID-hu Thy/Liv) wherein this conjoint hematopoietic organ that develops is a very useful and well established small chimeric animal model system to investigate the mechanisms and therapies for HIV induced hematopoietic inhibition. We will use the SCID-hu reconstitution system to induce or enhance and examine the self-renewal capacity and multilineage differentiation potential of the human CD34+ progenitor cells, for further enhancement of multilineage differentiation during HIV-1 infection in vivo.

To understand the in vivo role of HIV on hematopoiesis more completely by stem cell engraftment which can be easily manipulated in a suitable animal model, the same must also be susceptible to productive HIV infection. The chimeric SCID mouse coimplanted with human fetal thymus and liver tissues resulting in a functional human hematopoietic organ (Thy/Liv), provides an appropriate model to study the direct role of HIV on hematopoiesis in vivo , in the absence of confounding factors found in HIV infected patients. This model allows maintenance and differentiation through thymopoiesis of human hematopoietic progenitor cells and also recapitulates the effects of HIV-1 infection in the human thymus. An alternate model is the SCID mouse coengrafted with human peripheral blood lymphocytes (PBL) and bone marrow (BM) or umbilical cord blood (CB) wherein the PBL/BM or PBL/CB are intravenously injected into each animal. The observation that myeloid, erythroid, and megakaryocytoid progenitor cells can be detected in the Thy/Liv and PBL/BM or PBL/CB models, makes these models amenable to study which lineages of hematopoietic cells are susceptible to HIV infection and the differentiation stage at which they are infected. Currently we are also working on these models. The SCID-hu system also allows the controlled introduction of a cloned HIV strain into a functioning hematopoietic organ, in the absence of confounding factors such as opportunistic infections or antiretroviral or recreational drugs. In addition, no host immune response is mounted, thus eliminating immune mediated phenomena from the pathogenic profile. Since the mouse itself is not infected, effects of stress on normal murine physiologic functions also should be minimal. Lastly, the high virus loads seen following infection of SCID-hu make this model an extremely stringent tool to produce conditions for the susceptibility of the various precursor cells present to HIV-1 infection. Thus this model allows the causal role of HIV itself on hematopoiesis in vivo to be assessed under changing conditions of engraftment of HIV affected stem cells into new stromal microenvironment and therapeutic treatments including cytokines and stem cell growth factors. We will use the SCID-hu model to investigate the role of c-mpl in HIV-1 mediated multi-lineage hematopoietic inhibition to achieve sustained hematopoiesis, by introduction and expression of human STAT5A/B and c-mpl genes into CD34+c-mpl- cells, and combination Tpo and drug treatment of animals engrafted with these transduced or engineered cells.

It is hoped that the expected enhancement of self-renewal and multilineage differentiation will aid in decrease of HIV-1 induced hematopoietic inhibition, if c-mpl expression is maintained. This will then further reduce or prevent the occurrence of cytopenias in HIV infected individuals and undergoing highly active antiretroviral therapy (HAART). It will also have broader implications in the mechanisms and therapies for cytopenias in general and thrombocytopenia in particular, in heart disease and cancer therapy.

Current Research Interests

Stem cell therapies in HIV infection through stem cell and immune reconstitution using human hematopoietic progenitor stem cells in the SCID-hu system: Cytopenias including thrombocytopenia in diseases such as HIV infection, heart conditions and cancers; human hematopoietic stem cell differentiation in chimeric mouse-human SCID-hu model; role of proto-oncogene and thrombopoietin receptor, c-mpl, in stem cell differentiation, and its relationship to telomerase, apoptosis and signal transduction of c-mpl and STAT5 including thrombopoietin and other cytokine-receptor interactions in SCID-hu model; STAT5 transcription factors in self-renewal of CD34+ cells; reversal of HIV induced hematopoietic inhibition and rescue of multilineage hematopoiesis; stem cell reconstitution and gene therapeutic strategies with tightly controlled gene expression for containment of cytopenias and prevention of gene therapy induced malignancies, through preclinical translational research in vivo using SCID-hu model; mechanisms of resistance of progenitor stem cells to HIV infection.

Education

• 1967 - B.Sc. Chemistry Osmania University, Hyderabad, India
• 1973 - A.M. Physical Chemistry University of Missouri, Columbia, MO
• 1977 - Ph.D. Biochemistry Texas Tech University, Lubbock, TX

Professional Experience

• 1978 - 1980 - Postdoctoral Fellow, Department of Biochemistry, University of Georgia, Athens, GA
• 1980 - 1982 - Research Associate, Department of Biology, Brookhaven National Laboratory, Upton, NY
• 1982 - 1984 - Postdoctoral Fellow, Cold Spring Harbor Laboratory, NY
• 1984 - 1985 - Postdoctoral Associate, Center for Cancer Research, Department of Biology, MassachusettsInstitute of Technology, Cambridge, MA
• 1985 - 1988 - Research Fellow in Pathology, Harvard Medical School, Divisions of Immunogenetics and Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA
• 1988 - 1989 - Instructor in Pathology, Harvard Medical School, Division of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA
• 1989 - 1992 - Assistant Research Immunologist, Department of Surgery, David Geffen School of Medicine, University of California, Los Angeles, CA
• 1992 - 1995 - Assistant Research Neurologist, Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA
• 1995 - 1999 - Assistant Research Biologist, Division of Hematology-Oncology, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA
• 1999 - 2002 - Assistant Research Virologist, Department of Microbiology, Immunology and Molecular Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA
• 2002 - 2005 - Assistant Researcher, Department of Molecular and Medical Pharmacology,
  David Geffen School of Medicine, University of California, Los Angeles, CA
• 2005 - 2005 - Associate Researcher, Department of Molecular and Medical Pharmacology,
  David Geffen School of Medicine, University of California, Los Angeles, CA
• 2005 - Present - Associate Member, Laboratory of Stem Cell Biology,
  Torrey Pines Institute for Molecular Studies, San Diego, CA

Invited Seminar Presentations

• 1989 - University of Wisconsin, Madison, WI
• 1989 - Hoffman-LaRoche, Nutley, NJ
• 1989 - National Institutes of Health, Bethesda, MD
• 1989 - Tulane University, New Orleans, LA
• 1992 - Indian Institute of Science, Bangalore, India
• 1992 - Centre for Cellular and Molecular Biology, Hyderabad, India
• 1992 - National Institute of Immunology, New Delhi, India
• 1992 - Louisiana State University Medical Center, New Orleans, LA
• 1999 - Center for Blood Research, Harvard Medical School, Boston, MA
• 2001 - The University of Texas MD Anderson Cancer Center, Houston, TX
• 2002 - Centre for Cellular and Molecular Biology, Hyderabad, India
• 2004 - International Centre for Genetic Engineering and Biotechnology, New Delhi, India
• 2004 - University of Illinois College of Medicine, Rockford, IL
• 2005 - Western University of Health Sciences, Pomona, CA
• 2005 - University of California San Diego, La Jolla, Ca

Awards / Fellowships

• 1974 - 1977 - Robert A. Welch Foundation Predoctoral Fellow
• 1985 - 1987 - Leukemia Society of America Special Fellow
• 1992 - 1995 - National Institute of Mental Health Postdoctoral Fellow
• 1997 - 1999 - Elizabeth Glaser Pediatric AIDS Foundation Scholar Award

Honors / Committees / Journals

• 1979 - Presided the session on Bioluminescence & Chronobiology, 9th Annual Meeting,
  American Society for Photobiology, Asilomar, CA
• 1996 - Plenary Session Speaker at the Annual UCLA AIDS Symposium
• 2003 - Present  Honorary Member, International Advisory Council, VYOMA (Deemed University),
  Bangalore, India
• 2005 - Present   Editor, Journal of Stem Cells - Journal Website: www.novapublishers.com/JOSC
• 2005 - 2006   Reviewer, Scottish Executive Health Department, Edinburgh, United Kingdom
• 2006   Reviewer, AIDS Vaccines and Immunology Special Emphasis Panel, Center for Scientific Review, National Institutes of Health
• 2006 - 2007  Inclusion in the 9th Edition of Marquis Who's Who in Science and Engineering
• 2006 - Present  My more recent work is included in the newly formed stem cell research lab registry that includes scientists studying stem cell research www.stemcellscience.org/labs.php
• 2006   Reviewed for The Journal of Clinical Investigation
• 2006 - 2010  Peer Review Committee, American Heart Association, Western Review Consortium
• 2008   Inclusion in the 62nd Edition of Marquis Who's Who in America
• 2008  Inclusion in the 25th Edition of Marquis Who's Who in the World

Memberships in Professional Societies

• 1978 - 1982 - American Society for Photobiology
• 1991 - 1996 - American Association for the Advancement of Science
• 2004 - Present - American Society for Microbiology
• 2004 - Present - International Society for Stem Cell Research

Publications

1. Koka, P.S. Foreword: Stem Cells. J. Stem Cells 1: p. iii, 2006.
2. Sundell, I.B., Koka, P.S. Thrombocytopenia in HIV infection: impairment of platelet formation and loss correlates with increased c-Mpl and ligand thrombopoietin expression. Curr. HIV Res. 4:106-117, 2006.
3. Yunis, E.J., Zuniga, J., Koka, P.S., Husain, Z., Romero, V., Stern, J.N.H., Fridkis-Hareli, M. Stem cells in aging: Influence of ontogenic, genetic and environmental factors. J. Stem Cells 1(2): 125-147, 2006.

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4. Brooks, D.G., Cohen, M.D., Jamieson, B.D., Poon, B., Kitchen, S.G., Chow, S.A., Chen, I.S., Zack, J.A., Koka, P.S. Rapid size dependent deletion of foreign gene sequences inserted into attenuated HIV-1 upon infection in vivo: implications for vaccine development. Curr. HIV Res. 3:337-392, 2005.

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5. Koka, P.S., Kitchen, C.M., Reddy, S.T. Targeting c-Mpl for revival of human immunodeficiency virus type 1-induced hematopoietic inhibition when CD34+ progenitor cells are re-engrafted into a fresh stromal microenvironment in vivo. J. Virol. 78:11385-11392, 2004.
6. Koka, P.S., Reddy, S.T. Cytopenias in HIV infection: mechanisms and alleviation of hematopoietic inhibition. Curr. HIV Res. 2: 275-282, 2004.

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7. Koka, P.S., Brooks, D.G., Razai, A., Kitchen, C.M., Zack, J.A. HIV type 1 infection alters cytokine mRNA expression in thymus. AIDS Res. Hum. Retroviruses 19:1-12, 2003.

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8. Uittenbogaart, C.H., Boscardin, W.J., Anisman-Posner, D.J., Koka, P.S., Bristol, G., Zack, J.A. Effect of cytokines on HIV-induced depletion of thymocytes in vivo. AIDS 14:1317-1325, 2000.

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9. Koka, P.S., Jamieson, B.D., Brooks, D.G., Zack, J.A. Human immunodeficiency virus type 1-induced hematopoietic inhibition is independent of productive infection of progenitor cells in vivo. J. Virol. 73:9089-9097, 1999.

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10. Amado, R.G., Koka, P., Zack, J.A. Modeling precursor cell gene therapy and HIV pathogenesis in the SCID-hu mouse. Cancer Res. Ther. Cont. 7: 43-47, 1998.
11. Koka, P.S., Fraser, J.K., Bryson, Y., Bristol, G.C., Aldrovandi, G.M., Daar, E.S., Zack, J.A. Human immunodeficiency virus inhibits multilineage hematopoiesis in vivo. J. Virol. 72:5121-5127, 1998.

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12. Withers-Ward, E.S., Amado, R.G., Koka, P.S., Jamieson, B.D., Kaplan, A.H., Chen, I.S., Zack, J.A. Transient renewal of thymopoiesis in HIV-infected human thymic implants following antiviral therapy. Nature Med. 3:1102-1109, 1997.

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13. Koka, P., Merrill, J.E. The putative role of HIV-1 envelope proteins in the neuroimmunology and neuropathology of CNS AIDS. In Immunology of HIV Infection. Gupta, S. (Ed.), Plenum Press, New York, pp. 417-435, 1996.

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14. Koka, P., He, K., Camerini, D., Tran, T., Yashar, S.S., Merrill, J.E. The mapping of HIV-1 gp160 epitopes required for interleukin-1 and tumor necrosis factor alpha production in glial cells. J. Neuroimmunol. 57:179-191, 1995.
15. Koka, P., He, K., Zack, J.A., Kitchen, S., Peacock, W., Fried, I., Tran, T., Yashar, S.S., Merrill, J.E. Human immunodeficiency virus 1 envelope proteins induce interleukin 1, tumor necrosis factor alpha, and nitric oxide in glial cultures derived from fetal, neonatal, and adult human brain. J. Exp. Med. 182:941-952, 1995.

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16. Koka, P. Anti-HLA antibodies: detection and effect on renal transplant function. Transplant Proc. 25:243-244, 1993.
17. Koka, P., Chia, D., Terasaki, P.I., Chan, H., Chia, J., Ozawa, M., Lim, E. The role of IgA anti-HLA Class I antibodies in kidney transplant survival. Transplantation 56:207-211, 1993.
18. Lim, E.C., Chia, D., Gjertson, D.W., Koka, P., Terasaki, P.I. In vitro studies to explain high renal allograft survival in IgA nephropathy patients. Transplantation 55:996-999, 1993.

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19. Koka, P., van de Mark, K., Faller, D.V. Trans-activation of genes encoding activation-association human T-lymphocyte surface proteins by murine retroviral sequences. J. Immunol. 146:2417-2425, 1991.

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20. Koka, P., Cecka, J.M. Sex and age effects in renal transplantation. Clin. Transpl. 437-446, 1990.

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21. Koka, P., Cecka, J.M. Sensitization and crossmatching in renal transplantation. Clin. Transpl. 379-390, 1989.

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22. Koka, P., Yunis, J., Passarelli, A.L., Dubey, D.P., Faller, D.V., Yunis, E.J. Increased expression of CD4 molecules on Jurkat cells mediated by human immunodeficiency virus tat protein. J. Virol. 62:4353-4357, 1988.

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23. Koka, P. Stimulation of Escherichia coli DNA photoreactivating enzyme activity by adenosine 5'-triphosphate. Biochemistry 23:2914-2922, 1984.

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24. Lee, J., Carreira, L.A., Gast, R., Irwin, R.M., Koka, P., Small, E.D., Visser, A.J.W.G. Properties of a lumazine protein from the bioluminescent bacterium Photobacterium phosphoreum. In Bioluminescence and Chemiluminescence, pp. 103-112, Academic Press, NY, 1981.

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25. Small, E.D., Koka, P., Lee, J. Lumazine protein from the bioluminescent bacterium Photobacterium phosphoreum. Purification and characterization. J. Biol. Chem. 255:8804-8810, 1980.

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26. Koka, P., Lee, J. Separation and structure of the prosthetic group of the blue fluorescence protein from the bioluminescent bacterium Photobacterium phosphoreum. Proc. Natl. Acad. Sci. USA 76:3068-3072, 1979.

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27. Koka, P., Song, P.S. Protection of chlorophyll a by carotenoid from photodynamic decomposition. Photochem. Photobiol. 28:509-515, 1978.
28. Lee, J., Koka, P. Purification of blue fluorescence protein from the bioluminescent bacterium Photobacterium phosphoreum. Methods in Enzymology 57:226-234, 1978.

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29. Koka, P., Song, P.S. The chromophore topography and binding environment of peridinin-chlorophyll a-protein from marine dinoflagellate algae. Biochim. Biophys. Acta 495:220-231, 1977.

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30. Song, P.S., Koka, P., Prezelin, B.B., Haxo, F.T. Molecular topology of the photosynthetic light-harvesting pigment complex, peridinin-chlorophyll a-protein from marine dinoflagellates. Biochemistry 15:4422-4427, 1976.