My laboratory is interested in innate immune responses modulated by plasma proteins and expression of antimicrobial peptides regulated by signal transduction pathways in a model insect, the tobacco hornworm Manduca sexta. Insects lack an immunoglobulin-mediated acquired immunity, but they have developed an effective and sophisticated immune system similar to the innate immune system of vertebrates. In the innate immune system, recognition of pathogens and differentiation of nonself are critical to the host animals to trigger effective immune responses. Initial recognition of pathogens in innate immunity is mediated by pattern recognition receptors (PRRs) that can recognize structural molecular patterns, termed pathogen-associated molecular patterns (PAMPs), present on the surface of many microbes and pathogens but not on the host cells. Our research focuses on:
- C-type lectins as key PRRs in innate immune responses. C-type lectins are calcium-dependent carbohydrate-binding proteins. We have discovered a group of at least four C-type lectins, named immulectins, in M. sexta. These immulectins can enhance hemocyte (blood cell) phagocytosis, encapsulation and melanization. Our current work is to investigate how immulectins recognize and bind to microbial surface molecules such as bacterial lipopolysaccharide (LPS) and lipoteichoic acid (LTA), to trigger innate immune responses.
- Modulation of phenoloxidase (PO) activation. Melanotic encapsulation is an effective immune response to pathogens, particularly to large pathogens like nematodes and parasitoid eggs. Melanization requires activation of PO, a process that involves a cascade of serine proteinases. However, PO activation can also be modulated by non-enzymatic proteins. For example, we found that serine proteinase homologs (SPHs) are essential co-factors in PO activation by proteinases. We also found that a small cationic protein, lysozymes, and immulectins can either positively or negatively regulate PO activity. Currently, we are investigating how these proteins can modulate PO activation.
- Regulation of antimicrobial peptide genes. Insects can synthesize a variety of antimicrobial peptides (AMPs) upon microbial infections. The majority of AMPs is present in all insects, while some are species-specific. For example, Gloverin and Moricin are found only in Lepidoptera but not in Diptera (Drosophila and mosquitoes). Expression of AMPs is regulated by signal transduction pathways, such as the Toll and IMD (immune deficiency) pathways in Drosophila. Our research is to investigate how AMPs, particularly Gloverin and Moricin, are regulated in M. sexta hemocytes, and to identify additional signaling pathways that may activate AMPs by LPS.
Jing XP, Peng QH, Hu R, Zou HW, Wang HZ, Yu XQ, Zhou JW, Degen AA, Wang ZS. Dietary supplements during the cold season increase rumen microbial abundance and improve rumen epithelium development in Tibetan sheep. (2018). Journal of animal science, Journal Article.
Lin J, Xia X, Yu XQ, Shen J, Li Y, Lin H, Tang S, Vasseur L, You M. Gene expression profiling provides insights into the immune mechanism of Plutella xylostella midgut to microbial infection. (2018). Gene, 647 21-30. Journal Article.
Li Y, Huang X, Huang S, He H, Lei T, Saaoud F, Yu XQ, Melnick A, Kumar A, Papasian CJ, Fan D, Fu M. Central role of myeloid MCPIP1 in protecting against LPS-induced inflammation and lung injury. (2017). Signal transduction and targeted therapy, 2 17066. Journal Article.
Rao XJ, Zhan MY, Pan YM, Liu S, Yang PJ, Yang LL, Yu XQ. Immune functions of insect βGRPs and their potential application. (2017). Developmental and comparative immunology, Journal Article.
Zhang L, Zhao G, Hu X, Liu J, Li M, Batool K, Chen M, Wang J, Xu J, Huang T, Pan X, Xu L, Yu XQ, Guan X. Cry11Aa Interacts with the ATP-Binding Protein from Culex quinquefasciatus To Improve the Toxicity. (2017). Journal of agricultural and food chemistry, 65 (50), 10884-10890. Journal Article.
Xia X, You M, Rao XJ, Yu XQ. Insect C-type lectins in innate immunity. (2017). Developmental and comparative immunology, Journal Article.
Zhang L, Zhang X, Batool K, Hu X, Chen M, Xu J, Wang J, Pan X, Huang T, Xu L, Yu XQ, Guan X. Comparison and Mechanism of the UV-Resistant Mosquitocidal Bt Mutant LLP29-M19. (2018). Journal of medical entomology, 55 (1), 210-216. Journal Article.
Zhuo XR, Chen L, Wang GJ, Liu XS, Wang YF, Liu K, Yu XQ, Wang JL. 20-Hydroxyecdysone promotes release of GBP-binding protein from oenocytoids to suppress hemocytic encapsulation. (2017). Insect biochemistry and molecular biology, 92 53-64. Journal Article.
Li PK, Lui SL, Ng JK, Cai GY, Chan CT, Chen HC, Cheung AK, Choi KS, Choong HL, Fan SL, Ong LM, Yu LWL, Yu XQ. Addressing the burden of dialysis around the world: A summary of the roundtable discussion on dialysis economics at the First International Congress of Chinese Nephrologists 2015. (2017). Nephrology (Carlton, Vic.), 22 Suppl 4 3-8. Journal Article, Review.
Yu XQ, Luo Q, Kahn C, Cahill C, Weber M, Grogan P, Jemal A, O'Connell DL. Widening socioeconomic disparity in lung cancer incidence among men in New South Wales, Australia, 1987-2011. (2017). Chinese journal of cancer research = Chung-kuo yen cheng yen chiu, 29 (5), 395-401. Journal Article.
Deng KP, Fan YX, Ma TW, Wang Z, TanTai WJ, Nie HT, Guo YX, Yu XQ, Sun LW, Wang F. Carcass traits, meat quality, antioxidant status and antioxidant gene expression in muscle and liver of Hu lambs fed perilla seed. (2017). Journal of animal physiology and animal nutrition, Journal Article.
Islami F, Chen W, Yu XQ, Lortet-Tieulent J, Zheng R, Flanders WD, Xia C, Thun MJ, Gapstur SM, Ezzati M, Jemal A. Cancer deaths and cases attributable to lifestyle factors and infections in China, 2013. (2017). Annals of oncology : official journal of the European Society for Medical Oncology, 28 (10), 2567-2574. Journal Article.
Lv MQ, Wang J, Yu XQ, Hong HH, Ren WJ, Ge P, Zhou DX. Association between X-ray repair cross-complementing group 1(XRCC1) Arg399Gln polymorphism and endometriosis: A systematic review and meta-analysis. (2017). European journal of obstetrics, gynecology, and reproductive biology, 218 12-20. Journal Article.
Yu XQ, Wang MH, Li JS, Li SY, Xie Y, Bai YP, Zhang HL, Cao F, Hou CX, Ma LJ. Effect of comprehensive therapy based on Chinese medicine patterns on self-efficacy and effectiveness satisfaction in chronic obstructive pulmonary disease patients. (2017). Chinese journal of integrative medicine, Journal Article.
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