Associate Professor of Medicine
Specialty Areas: immunology, autoimmunity, inflammation
Chronology: MD: Shandong University School of Medicine, 1987; PhD: University of North Carolina at Chapel Hill, 2004; Postdoctoral Fellow: University of North Carolina at Chapel Hill, 2004-2008; Assistant Professor of Medicine: University of North Carolina at Chapel Hill, 2008-2012; Associate Professor of Medicine: University of North Carolina at Chapel Hill, 2013-present.
Description of research and/or clinical interests: The primary role of the immune cells is to protect tissues from damage by infection and harmful signals. However, sustained and uncontrolled mobilization of immune cells induces tissue damage. Monocytes are precursors of dendritic cells and macrophages during inflammation and can be divided into two major subsets in mice and humans, based on the expression of two chemokine receptors, CCR2 and CX3CR1. The research in Dr. Liu’s laboratory focuses on immune cell migration and function in inflammatory diseases, such as rheumatoid arthritis and atherosclerosis. One ongoing project studies the differentiation and migration of monocyte subsets in autoimmune arthritis. Because CCR2 deficiency and CX3CR1 deficiency give rise to different disease phenotypes, the group is interested in understanding how autoimmune-induced inflammation drives monocyte differentiation into dendritic cells, macrophages, myeloid-derived suppressor cells, and bone destructive osteoclasts. Reciprocally, the group is investigating how monocyte and monocyte-derived cells regulate T cell and B cell responses and consequently joint inflammation during the disease process. Another ongoing project is focused on understanding how chemokine receptors and monocyte subsets regulate the recruitment and function of dendritic cells and macrophages to the vessel wall and the contribution of these cells to the pathogenesis of atherosclerosis. The ultimate goal of Dr. Liu’s research is to decipher the signaling and cellular events that initiate and perpetuate autoimmune and inflammatory diseases and identify new therapeutic targets.
Pietrosimone KM, Jin M, Poston B, and Liu P. (2015). Collagen-induced arthritis: a model for murine autoimmune arthritis. Bop-protocol 5(20): e1626.
Crook KR, Jin M, Weeks MF, Rampersad RR, Baldi RM, Glekas AS, Shen Y, Esserman DA, Little P, Schwartz TA, Liu P. (2015). Myeloid-derived suppressor cells regulate T cell and B cell responses during autoimmune disease. J Leukoc Biol 97(3):572082. Doi: 10.1189/jlb. 4A0314-139R. PMID: 25583578.
Crook KR and Liu P. Role of myeloid-derived suppressor cells in autoimmune disease. (2014) World J Immunol 4(1):26-33. PMID: 25621222
Giguère PM, Billard MJ, Laroche G, Buckley BK, Timoshchenko RG, McGinnis MW, Esserman D, Foreman O, Liu P, Siderovski DP, Tarrant TK. (2013). G-protein signaling modulator-3, a gene linked to autoimmune diseases, regulates monocyte function and its deficiency protects from inflammatory arthritis. Mol Immunol 54(2):193-8. PubMed PMID: 23280397.
Tarrant TK, Liu P, Rampersad RR, Esserman D, Rothlein LR, Timoshchenko RG, McGinnis MW, Fitzhugh DJ, Patel DD, Fong AM. (2012). Decreased Th17 and antigen-specific humoral responses in CX₃ CR1-deficient mice in the collagen-induced arthritis model. Arthritis Rheum 64(5):1379-87. PubMed PMID: 22144035.
Rampersad RR, Tarrant TK, Vallanat CT, Quintero-Matthews T, Weeks MF, Esserman DA, Clark J, Di Padova F, Patel DD, Fong AM, Liu P. (2011). Enhanced Th17-cell responses render CCR2-deficient mice more susceptible for autoimmune arthritis. PLoS One 6(10):e25833. PubMed PMID: 21991368.
Jerath MR, Liu P, Struthers M, Demartino JA, Peng R, Peterson LB, Cumiskey AM, Yang L, Rojas M, Patel DD, Fong AM. (2010). Dual targeting of CCR2 and CX3CR1 in an arterial injury model of vascular inflammation. Thromb J 8:14. PubMed PMID: 20836883.
Tarrant TK, Rampersad RR, Esserman D, Rothlein LR, Liu P, Premont RT, Lefkowitz RJ, Lee DM, Patel DD. (2008). Granulocyte chemotaxis and disease expression are differentially regulated by GRK subtype in an acute inflammatory arthritis model (K/BxN). Clin Immunol 129(1):115-22. PubMed PMID: 18662895.
Liu P, Yu YR, Spencer JA, Johnson AE, Vallanat CT, Fong AM, Patterson C, Patel DD. (2008). CX3CR1 deficiency impairs dendritic cell accumulation in arterial intima and reduces atherosclerotic burden. Arterioscler Thromb Vasc Biol 28(2):243-50. PubMed PMID: 18079406.
Jerath MR, Kwan M, Liu P, Patel DD. (2007). Chemokine receptors and atherosclerosis. Harrison JK, Lukacs NW, editors. NJ: Humana Press 177-234p.
Liu P, Patil S, Rojas M, Fong AM, Smyth SS, Patel DD. (2006). CX3CR1 deficiency confers protection from intimal hyperplasia after arterial injury. Arterioscler Thromb Vasc Biol 26(9):2056-62. PubMed PMID: 16809547.
Liu P, Osawa S, Weiss ER. (2005). M opsin phosphorylation in intact mammalian retinas. J Neurochem 93(1):135-44. PubMed PMID: 15773913.
Liu P, Roush ED, Bruno J, Osawa S, Weiss ER. (2004). Direct binding of visual arrestin to a rhodopsin carboxyl terminal synthetic phosphopeptide. Mol Vis 10:712-9. PubMed PMID: 15480300.