This is a competitive renew of a grant that has uncovered the essential roles of a heat shock protein (HSP) gp96 (also known as grp94 and HSP90b1) in chaperoning multiple TLRs in the endoplasmic reticulum. TLRs are critical sensors for pathogens in the initiation of innate immunity and for subsequent activation of adaptive immunity. Until recently, research in TLR biology has been focused primarily on downstream signaling events. It is increasingly appreciated that TLR biogenesis and trafficking are also tightly regulated to prevent inflammation and autoimmunity. My laboratory is at the forefront to address the function of gp96 using genetic approaches. We have discovered and published in the last funding period that: (i) gp96 is a master chaperone for both cell surface and intracellular TLRs;(ii) gp96 is not required for the assembly of immunoglobulin but it plays critical roles in the proper compartmentalization of B1 cells and marginal zone B cells due to its ability to also chaperone integrins;(iii) the Drosophila gp93 is the gp96 ortholog in that it can rescue the expression of both TLRs and integrins in gp96 KO murine cells;(iv) gp96 is critical for T and B lymphopoiesis but not myelopoiesis;(v) the folding of TLRs by gp96 is dependent on a substrate (TLR)-specific co-chaperone, CNPY3 (also known as PRAT4A). Unexpectedly, we have made two additional novel observations. First, gp96 plays critical roles in canonical Wnt signaling such that when gp96 is deleted from the gut, mice develop a profound and lethal enterocolitis. Second, when gp96 was selectively knocked down from macrophages, we observed a significant attenuation of inflammation-associated colon cancer and a concurrent reduction of IL23 and IL17. We thus hypothesize that gp96 provide a crucial link for multiple processes including inflammation, tissue homeostasis and cancer. We will tackle our hypothesis with the following three specific aims: (1) Determine the molecular mechanisms of gp96 in folding TLRs with specific focus on the roles of co-chaperones. (2) Establish the roles and mechanisms of gp96 in gut homeostasis. (3) Dissect the macrophage-intrinsic roles and mechanisms of gp96 in inflammation-associated colon cancer. Successful execution of our proposal shall significantly advance the field of chaperone biology, innate immunity, inflammation and tumor immunology.
Proteins need to be folded into proper three-dimensional structure in order to have their biological function, which is often carried out by proteins called molecular chaperones. This project addresses the function and mechanism of one such chaperone that is particularly important in folding immune sensors to regulate inflammation and cancer. Knowledge learnt from this proposal should facilitate the development of novel drugs for the treatment of a variety of diseases such as sepsis, cancer and autoimmune disease.
|Rachidi, Saleh; Wallace, Kristin; Wrangle, John M et al. (2016) Neutrophil-to-lymphocyte ratio and overall survival in all sites of head and neck squamous cell carcinoma. Head Neck 38 Suppl 1:E1068-74|
|Ansa-Addo, Ephraim A; Thaxton, Jessica; Hong, Feng et al. (2016) Clients and Oncogenic Roles of Molecular Chaperone gp96/grp94. Curr Top Med Chem 16:2765-78|
|Anas, Adam A; de Vos, Alex F; Hoogendijk, Arie J et al. (2016) Endoplasmic reticulum chaperone gp96 in macrophages is essential for protective immunity during Gram-negative pneumonia. J Pathol 238:74-84|
|Salem, Mohamed L; El-Badawy, Ahmed S; Li, Zihai (2015) Immunobiology and signaling pathways of cancer stem cells: implication for cancer therapy. Cytotechnology 67:749-59|
|Lu, Shengjun; Zhang, Jinyu; Liu, Dai et al. (2015) Nonblocking Monoclonal Antibody Targeting Soluble MIC Revamps Endogenous Innate and Adaptive Antitumor Responses and Eliminates Primary and Metastatic Tumors. Clin Cancer Res 21:4819-30|
|Zhang, Yongliang; Ansa-Addo, Ephraim; Li, Zihai (2015) GP96: safeguarding Treg. Oncotarget 6:19936-7|
|Patel, Hardik J; Patel, Pallav D; Ochiana, Stefan O et al. (2015) Structure-activity relationship in a purine-scaffold compound series with selectivity for the endoplasmic reticulum Hsp90 paralog Grp94. J Med Chem 58:3922-43|
|Li, Yan; Chitnis, Nilesh; Nakagawa, Hiroshi et al. (2015) PRMT5 is required for lymphomagenesis triggered by multiple oncogenic drivers. Cancer Discov 5:288-303|
|Liu, Delong; Sun, Weijing; Hou, Jingzhou et al. (2015) Pass quantity, focus on quality. J Hematol Oncol 8:27|
|Rachidi, Saleh; Sun, Shaoli; Li, Zihai (2015) Endoplasmic reticulum heat shock protein gp96/grp94 is a pro-oncogenic chaperone, not a tumor suppressor. Hepatology 61:1766-7|
Showing the most recent 10 out of 36 publications