Li Zhang
 

Li Zhang Ph.D.
Academic Title: Associate Professor
Primary Appointment: Physiology
Secondary Appointments: Surgery
lizhang@som.umaryland.edu
Location: UMB BioPark Building 1, 216
Phone: 410-706-8040
Fax: 410-706-8121

Personal History

I received my PhD in Biochemistry and Molecular Biology and also had my postdoctoral training at the University of Notre Dame, Notre Dame, Indiana.  I joined the faculty of the University of Maryland, School of Medicine in 2004 as an Associate Professor.  My research program has been continuously funded and supported by the National Institute of Health and the American Hearst Association.  I’m also associated with a training grant from the National Institute of Health.

Research Interests

Stem cells possess the ability to self-renew and to differentiate into multiple tissue types, and thus are ideal source of cells for tissue repair and regeneration. However, successful stem cell-based tissue regeneration depends on our ability to prepare a homogenous stem cell population and to overcome tissue rejection mediated by host immune cells.  Thus, our research program comprises two separate projects: one is focused on the roles of mesenchymal stem cells in tissue repair/regeneration and the other is to study the roles of leukocytes in physiological processes, e.g. innate and adaptive immune responses, and in disease development, e.g. atherosclerosis, myocardial infarction, stroke, and osteoporosis.

The long term goal of our research is to better understand the biology of leukocyte integrins, especially the CD18 integrin subfamily, and their roles in both physiological and pathological processes. In particular, our studies will focus on the molecular mechanisms that allow leukocytes to migrate within inflammatory environments (Fig. 1) and to recognize a wide range of physiological and pathological targets via integrin receptors. In addition, based on our recent finding that the CD18 integrin is also expressed by the primitive stromal stem cells and can be used as a cell marker to enrich the stem cell population from total human bone marrow (Fig. 2), we will study the role of CD18 in stromal stem cell proliferation and differentiation, tissue repair and regeneration, as well as its role in the maintenance of a niche microenvironment that is critical to the function of hematopoietic stem cells.  The information generated from these studies can be used to assist us in the design of therapeutic reagents that will selectively target the deleterious effects of leukocyte engagement, such as their contributions to pathogenesis of atherosclerosis, arthritis, and other autoimmune diseases, while keeping its host defense functions intact.  It can also assist the isolation and enrichment of stromal stem cells for clinical applications.

Our current research interests include:

1.      Structure-function studies of the CD18 integrins: the molecular basis of integrin ligand binding and integrin activation.
2.      Macrophage trafficking during inflammation and its resolution.
3.      Tissue repair and regeneration using stromal stem cells.
4.      Identification of an unknown mutation in a human patient that causes defective integrin activation.
 

Lab Techniques and Equipment

  1. Various knockout and transgenic mice for evaluating the roles of different proteins and receptors in health and disease.
  2. Commonly used mouse models in the laboratory
    • Balloon angioplasty model
    • melanoma tumor growth model
    • ectopic bone and bone marrow regeneration
    • oral and intravenous immune tolerance model
  1. Adoptive cell transfer and bone marrow transplantation to study the contribution of a particular protein, surface receptor or cell population in leukocyte functions;
  2. Laser scanning confocal fluorescence microscopy and FRET to study protein interactions;
  3. Live cell imaging to study cell migration;  
  4. FACS cell sorting to enrich a particular stem cell population;
  5. Real time RT-PCR, 2D PAGE, and Mass spectroscopy to study gene expression;
  6. Protein expression in E.coli, Sf9 insect cells, and yeasts, as well as adherent and suspension eukaryotic cells.

Laboratory Personnel:

  • Chunzhang Cao (postdoctoral fellow) Study of macrophage trafficking
  • Driss Ehirchiou (postdoctoral fellow) Study of immune regulation

Publications

1.       Zhang, L. and Castellino, F.J. (1989) Generation of an antibody with a designed specificity difference for protein C and activated protein C. Journal of Protein Chemistry, 8:471-480.
2.       Zhang, L. and Castellino, F.J.  (1990) A g-carboxyglutamic acid (g variant g6D,g7D) of human activated protein C displays greatly reduced activity as an anticoagulant. Biochemistry, 29:10828-10834.
4.       Zhang, L., Jhingan, A., and Castellino, F.J.  (1992) Role of individual g-carboxyglutamic acid residues of activated human protein C in defining its in vitro anticoagulant activity. Blood, 80: 942-952.
5.       Zhang, L. and Castellino, F.J.  (1992) Influence of specific g-carboxyglutamic acid residues on the integrity of the calcium-dependent conformation of human protein C. Journal of Biological Chemistry, 267: 26078-26084.
6.       Zhang, L. and Castellino, F.J. (1993) The contributions of individual g-carboxyglutamic acid residues in the calcium-dependent binding of recombinant human protein C to acidic phospholipid vesicles.  Journal of Biological Chemistry, 268: 12040-12045.
7.       Yu. S., Zhang, L., Jhingan, A., Christiansen, W.T. and Castellino, F.J. (1994) Construction, expression, and properties of a recombinant chimeric human protein C with replacement of its growth factor-like domains by those of human coagulation factor IX. Biochemistry, 33: 823-831.
10.   Zhang, L., Muchowski, P.J., Chang, E.R., Soule, H.R., Plow, E.F. and Moyle, M. (1994) Functional interaction between the integrin antagonist NIF and the I domain of CD11b/CD18. Journal of Biological Chemistry, 269: 26419-26423.
12.   Zhang, L., and Plow, E.F. (1996) A discrete site modulates activation of I domains: application to integrin aMb2. Journal of Biological Chemistry, 271: 29953-29957.
13.   Zhang, L., and Plow, E.F. (1997) Identification and reconstruction of the binding site within aMb2 for a specific and high affinity ligand, NIF. Journal of Biological Chemistry.  272: 17558-17564.
14.   Plow, E.F. and Zhang, L. (1997) A MAC-1 attack: integrin functions directly challenged in knock-out mice. Journal of Clinical Investigation 99:1145-1146.
15.   Zaffran, Y., Zhang, L., and Ellner J.J. (1998) Role of CR4 in mycobacterium tuberculosis human macrophages binding and signal transduction in the absence of serum. Infection and Immunity, 66(9): 4541-4.
17.   Ugarova, T.P., Solovjov, D.A., Zhang, L., Loukinov, D.I., Yee, V.C., Medved, L.V., and Plow, E.F.  (1998) Identification of a novel recognition sequence for integrin aMb2 within the g-chain of fibrinogen.  Journal of Biological Chemistry, 273: 22519-22527.
18.   Cierniewski, C.S., Byzowa, T.,  Papierak, M., Haas, T.A., Niewiarowska, J., Zhang, L., Cieslak, M., and Plow, E.F. (1999) Peptides that mimic natural contact points of fibrinogen for aIIbb3 bind simultaneously to distinct subsites on the receptor and induce differential conformational and microenvironmental changes. Journal of Biological Chemistry, 274: 16923-16932,
19.   Zhang, L. (1999) The aMb2 integrin and its role in neutrophil function. Cell Research 9:171-178.
21.   Simon, D.I., Chen, Z., Xu, H., Li, C.Q., Dong, J., McIntire, L.V., Ballantyne, C.M., Zhang, L., Furman, M.I., Berndt, M.C., and Lopez, J.A. (2000) Platelet glycoprotein ibalpha is a counterreceptor for the leukocyte integrin Mac-1 (CD11b/CD18). Journal of Experimental Medicine 192:193-204.
22.   Simon, D.I., Wei, Y., Zhang, L., Rao, N.K., Xu, H., Chen, Z., Liu, Q., Rosenberg, S., and Chapman, H.A. (2000) Identification of a urokinase receptor-integrin interaction site: promiscuous regulator of integrin function. Journal of Biological Chemistry, 275: 10228-10234.
23.   Plow, E.F., Haas, T.A., Zhang, L., Loftus, J. and Smith, J.W.  (2000) Ligand binding to integrins. Journal of Biological Chemistry  275:21785-21788.
24.   Yakubenko, V.P., Solovjov, D.A., Zhang, L., Yee, V.C., Plow, E.F., and Ugarova, T.P. (2001) Identification of the binding site for fibrinogen recogntion peptide g383-395 within the aMI-domain of integrin aMb2.  Journal of Biological Chemistry, 276: 13995-14003.
25.   Xiong, Y. M., and Zhang, L. (2001) Structure-function of the putative I-domain within the integrin b2 subunit.  Journal of Biological Chemistry, 276: 19340-19349.
26.   Xiong, Y. M., Haas, T.A., and Zhang, L. (2002) Identification of Functional Segments within the b2I-domain of Integrin alphaM beta2. Journal of Biological Chemistry 277: 46639-46644.
27.   Cierniewska-Cieslak, A., Cierniewski, C.S., Blecka, K., Papierak, M., Michalec, L., Zhang,L., Haas, T.A., and Plow, E.F. (2002) Identification and characterization of two cation binding sites in the integrin beta 3 subunit. Journal of Biological Chemistry, 277: 11126-11134.
28.   Castellino, F.J., Ploplis, V.A. and Zhang, L. (2002) g-glutamate and b-Hydroxyaspartate in Proteins.  Posttranslational Modifications of Proteins: Tools for Functional Proteomics. Edited by C. Kannicht, Chapter 17, page 259-268.
29.   Li, Y. and Zhang, L. (2003) The fourth blade within the beta-propeller is involved specifically in C3bi recognition by integrin alphaM beta2. Journal of Biological Chemistry 278:34395-34402.
30.   Xiong, Y. M., Chen, J., and Zhang, L. (2003) Modulation of CD11b/CD18 adhesive activity by its extracellular membrane-proximal regions. Journal of Immunology 171:1042-1050.
31.   Li, Y., D.A. Lawrence, D.A., and Zhang, L. (2003) Sequences within Domain II of the Urokinase Receptor Critical for Differential Ligand Recognition. Journal of Biological Chemistry 278: 29925-29932.
32.   Ehirchiou, D., Xiong, Y.M., Li, Y., Brew, S., and Zhang. L. (2005) Dual function for a unique site within the b2I-domain of integrin alphaMbeta2. Journal of Biological Chemistry 280:8324-8331.
33.   Cao, C., Lawrence, D.A., Strickland, D., and Zhang, L. (2005) A specific role of integrin mac-1 in accelerated macrophage efflux to the lymphatics. Blood, 106: 3234-3241, 2005. Also see commentary “Mac-1 mediates migration to lymph nodes” by Joseph P. Mizgerd (Blood 106:2927-2928).
35.   Miura, Y., Miura, M., Gronthos, S., Allen, M.R., Cao, C., Uveges, T.E., Bi, Y., Shi, S., and Zhang, L.  (2005) Integrin beta2 is a novel surface marker for bone marrow stromal stem cells and plays an important role in osteogenic differentiation in vivo. Proceedings of the National Academy of Sciences 102:14022-14027.  see Report on SOM news vol7 number 4, page 2.
36.   Cao, C., Lawrence, Li, Y., Von Arnim, C.A., Herz, J., Hyman, B.T., D.A., Strickland, D., and Zhang, L. (2006) Fibrinolytic inhibitor PAI-1 and endocytic receptor LRP coordinate Mac-1-dependent macrophage migration into the lymphatic system. EMBO J 2006, 25:1860–1870.
37.   Cao, C., Lawrence, D.A., Li, Y., Von Arnim, C.A., Herz, J., Su, EJ, Makarova, A, Hyman, B.T., D.A., Strickland, D., and Zhang, L. (2006) Endocytic receptor LRP together with tPA and PAI-1 coordinates Mac-1-dependent macrophage migration.  The EMBO Journal, 25:1860-1870.
38.   Xiong, Y., Cao, C., Makarova, A., Hyman, B., and Zhang, L. (2006) Mac-1 promotes FcgRIIA-dependent cell spreading and migration on immune complexes. Biochemistry 45:8721-31.
39.   Miura, Y., Gao, Z., Miura, M., Seo, B.M., Sonoyama, W., Chen, W., Gronthos, S., Zhang, L., and Shi, S. (2006) Mesenchymal Stem Cell-Organized Bone Marrow Elements: An Alternative Hematopoietic Progenitor Resource.  Stem Cells 24:2428-2436.
40.   Tang, P., Cao, C., Xu, M., and Zhang, L. (2007) Regulation of integrin activation by cytoskeletal protein Radixin.  FEBS Letters 581:1103-1108.
41.   Ehirchiou, D., Xiong, Y., Xu, G., Chen, W., Shi, Y., and Zhang, L. (2007) CD11b Facilitates the Development of Peripheral Tolerance by Suppressing Th17 Differentiation. Journal Experimental Medicine 204:1519-24.
42.   Bi, Y., Ehirchiou, D., Kilts, T.M., Inkson, C.A., Embree, M.C., Sonoyama, W., Li, L., Leet, A.I., Seo, B., Zhang, L., Shi, S., and Young, M.F. (2007) Identification of tendon stem/progenitor cells and the role of the extracellular matrix in their niche. Nature Medicine. 13:1219-1227.



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