Deepta Bhattacharya

Deepta Bhattacharya

Associate Professor, BIO5 Institute
Associate Professor, Cancer Biology - GIDP
Associate Professor, Genetics - GIDP
Associate Professor, Surgery
Member of the Graduate Faculty
Professor, Immunobiology
Primary Department
Department Affiliations
Contact
(520) 626-8088

Research Interest

Research Interest
Research in the Bhattacharya lab focuses on molecular approaches to direct B cell differentiation to establish immunity to infectious disease, and stem cell differentiation for regenerative medicine. Current projects in the lab include: 1) Understanding the cellular basis of antibody-mediated immunity to variable viruses. After infection or vaccination, B cells that recognize the pathogen proliferate and undergo a massive level of expansion. Upon clearance of the infection a small fraction of the "best" B cells are retained to become memory B cells or long-lived plasma cells. Our recent work has established that memory B cells are excellent at recognizing not only the original pathogen, but also mutant escape variants of the pathogen. In contrast, long-lived plasma cells are highly specific only for the original pathogen. We are studying the transcription factors that regulate the memory B cell vs. long-lived plasma cell fate, and are studying mechanisms to alter this fate to provide effective immunity against mutable viruses such as influenza and Dengue. 2) Identifying molecular regulators of the duration of immunity. Most clinically used vaccines rely on the production of antibodies to confer immunity. The duration of immunity can vary greatly between different vaccines, yet the molecular basis of this remains unknown. Current efforts are focused on the identification of genes that regulate plasma cell lifespan and on the features of the vaccine that confer durable antibody immunity. 3) Engineering human pluripotent stem cells to generate antibody-mediated immunity. A small fraction of patients infected with HIV or dengue virus, or vaccinated against influenza develop remarkable antibodies that neutralize nearly all clinical isolates of these viruses. Yet it is unclear how to induce these types of antibodies in the broader population through standard vaccination. Using novel targeted nuclease technologies, we are engineering human embryonic stem cells to express these antibodies and differentiating them into transplantable long-lived plasma cells. The long-term goal of this project is to provide permanent immunity to recipients of these engineered plasma cells.

Publications

Bhattacharya, D., Ehrlich, L. I., & Weissman, I. L. (2008). Space-time considerations for hematopoietic stem cell transplantation. European journal of immunology, 38(8), 2060-7.

The mammalian blood system contains a multitude of distinct mature cell lineages adapted to serving diverse functional roles. Mutations that abrogate the development or function of one or more of these lineages can lead to profound adverse consequences, such as immunodeficiency, autoimmunity, or anemia. Replacement of hematopoietic stem cells (HSC) that carry such mutations with HSC from a healthy donor can reverse such disorders, but because the risks associated with the procedure are often more serious than the blood disorders themselves, bone marrow transplantation is generally not used to treat a number of relatively common inherited blood diseases. Aside from a number of other problems, risks associated with cytoreductive treatments that create "space" for donor HSC, and the slow kinetics with which immune competence is restored following transplantation hamper progress. This review will focus on how recent studies using experimental model systems may direct future efforts to implement routine use of HSC transplantation to cure inherited blood disorders.

Becker, A. M., Callahan, D. J., Richner, J. M., Choi, J., DiPersio, J. F., Diamond, M. S., & Bhattacharya, D. (2015). GPR18 Controls Reconstitution of Mouse Small Intestine Intraepithelial Lymphocytes following Bone Marrow Transplantation. PloS one, 10(7), e0133854.

Specific G protein coupled receptors (GPRs) regulate the proper positioning, function, and development of immune lineage subsets. Here, we demonstrate that GPR18 regulates the reconstitution of intraepithelial lymphocytes (IELs) of the small intestine following bone marrow transplantation. Through analysis of transcriptional microarray data, we find that GPR18 is highly expressed in IELs, lymphoid progenitors, and mature follicular B cells. To establish the physiological role of this largely uncharacterized GPR, we generated Gpr18-/- mice. Despite high levels of GPR18 expression in specific hematopoietic progenitors, Gpr18-/- mice have no defects in lymphopoiesis or myelopoiesis. Moreover, antibody responses following immunization with hapten-protein conjugates or infection with West Nile virus are normal in Gpr18-/- mice. Steady-state numbers of IELs are also normal in Gpr18-/- mice. However, competitive bone marrow reconstitution experiments demonstrate that GPR18 is cell-intrinsically required for the optimal restoration of small intestine TCRγδ+ and TCRαβ+ CD8αα+ IELs. In contrast, GPR18 is dispensable for the reconstitution of large intestine IELs. Moreover, Gpr18-/- bone marrow reconstitutes small intestine IELs similarly to controls in athymic recipients. Gpr18-/- chimeras show no changes in susceptibility to intestinal insults such as Citrobacter rodentium infections or graft versus host disease. These data reveal highly specific requirements for GPR18 in the development and reconstitution of thymus-derived intestinal IEL subsets in the steady-state and after bone marrow transplantation.

Satpathy, A. T., Briseño, C. G., Cai, X., Michael, D. G., Chou, C., Hsiung, S., Bhattacharya, D., Speck, N. A., & Egawa, T. (2014). Runx1 and Cbfβ regulate the development of Flt3+ dendritic cell progenitors and restrict myeloproliferative disorder. Blood, 123(19), 2968-77.

Runx1 and Cbfβ are critical for the establishment of definitive hematopoiesis and are implicated in leukemic transformation. Despite the absolute requirements for these factors in the development of hematopoietic stem cells and lymphocytes, their roles in the development of bone marrow progenitor subsets have not been defined. Here, we demonstrate that Cbfβ is essential for the development of Flt3(+) macrophage-dendritic cell (DC) progenitors in the bone marrow and all DC subsets in the periphery. Besides the loss of DC progenitors, pan-hematopoietic Cbfb-deficient mice also lack CD105(+) erythroid progenitors, leading to severe anemia at 3 to 4 months of age. Instead, Cbfb deficiency results in aberrant progenitor differentiation toward granulocyte-macrophage progenitors (GMPs), resulting in a myeloproliferative phenotype with accumulation of GMPs in the periphery and cellular infiltration of the liver. Expression of the transcription factor Irf8 is severely reduced in Cbfb-deficient progenitors, and overexpression of Irf8 restors DC differentiation. These results demonstrate that Runx proteins and Cbfβ restrict granulocyte lineage commitment to facilitate multilineage hematopoietic differentiation and thus identify their novel tumor suppressor function in myeloid leukemia.

Wang, Y., & Bhattacharya, D. (2014). Adjuvant-specific regulation of long-term antibody responses by ZBTB20. The Journal of experimental medicine, 211(5), 841-56.

The duration of antibody production by long-lived plasma cells varies with the type of immunization, but the basis for these differences is unknown. We demonstrate that plasma cells formed in response to the same immunogen engage distinct survival programs depending on the adjuvant. After alum-adjuvanted immunization, antigen-specific bone marrow plasma cells deficient in the transcription factor ZBTB20 failed to accumulate over time, leading to a progressive loss of antibody production relative to wild-type controls. Fetal liver reconstitution experiments demonstrated that the requirement for ZBTB20 was B cell intrinsic. No defects were observed in germinal center numbers, affinity maturation, or plasma cell formation or proliferation in ZBTB20-deficient chimeras. However, ZBTB20-deficient plasma cells expressed reduced levels of MCL1 relative to wild-type controls, and transgenic expression of BCL2 increased serum antibody titers. These data indicate a role for ZBTB20 in promoting survival in plasma cells. Strikingly, adjuvants that activate TLR2 and TLR4 restored long-term antibody production in ZBTB20-deficient chimeras through the induction of compensatory survival programs in plasma cells. Thus, distinct lifespans are imprinted in plasma cells as they are formed, depending on the primary activation conditions. The durability of vaccines may accordingly be improved through the selection of appropriate adjuvants.

Bhattacharya, D., Rossi, D. J., Bryder, D., & Weissman, I. L. (2006). Purified hematopoietic stem cell engraftment of rare niches corrects severe lymphoid deficiencies without host conditioning. The Journal of experimental medicine, 203(1), 73-85.

In the absence of irradiation or other cytoreductive conditioning, endogenous hematopoietic stem cells (HSCs) are thought to fill the unique niches within the bone marrow that allow maintenance of full hematopoietic potential and thus prevent productive engraftment of transplanted donor HSCs. By transplantation of purified exogenous HSCs into unconditioned congenic histocompatible strains of mice, we show that approximately 0.1-1.0% of these HSC niches are available for engraftment at any given point and find no evidence that endogenous HSCs can be displaced from the niches they occupy. We demonstrate that productive engraftment of HSCs within these empty niches is inhibited by host CD4+ T cells that recognize very subtle minor histocompatibility differences. Strikingly, transplantation of purified HSCs into a panel of severe combined immunodeficient (SCID) mice leads to a rapid and complete rescue of lymphoid deficiencies through engraftment of these very rare niches and expansion of donor lymphoid progenitors. We further demonstrate that transient antibody-mediated depletion of CD4+ T cells allows short-term HSC engraftment and regeneration of B cells in a mouse model of B(-) non-SCID. These experiments provide a general mechanism by which transplanted HSCs can correct hematopoietic deficiencies without any host conditioning or with only highly specific and transient lymphoablation.