Despite decades of research, virus infection remains a serious worldwide health threat. Clearly, new ideas and out-of-the-box approaches must be pursued. Many pathogenic viruses, such as influenza, human immunodeficiency, West Nile, and herpes virus, have surface envelopes loaded with carbohydrate-modified proteins encoded by the viral genome. Importantly, these surface """"""""glycoproteins"""""""" are essential for viral infection, so preventing their assembly represents a very promising anti-viral target. The glycoproteins are generally of the N-linked class, which have glycans attached to asparagine residues. Mammalian host cells also synthesize their own N-linked glycoproteins. Thus, to produce their envelope proteins and attach the N-linked glycans, viruses must hijack the host's N-linked glycosylation pathway. This proposal will elucidate a novel anti-viral defense mechanism that prevents this hijacking, and which we hypothesize hinders infection. The antiviral mechanism uses a new signaling pathway elucidated by the P.I. specifically;the P.I. discovered that the common metabolite mannose-6-phosphate (M6P) is generated by glycogen breakdown for double-duty as a 2nd-messenger signaling molecule activated by viral infection. M6P signaling triggers a specific process for destruction of lipid-linked oligosaccharides (LLOs), which in mammals are conjugates of a 14-sugar oligosaccharide (Glc3Man9GlcNAc2) and the carrier lipid dolichol, connected by a pyrophosphate bond. Free Glc3Man9GlcNAc2 and dolichol phosphate result from LLO destruction by M6P signaling. A key point is that since LLOs are the glycan donors for N-linked glycosylation, LLO destruction by M6P signaling is predicted to impair viral N-glycosylation and infectivity. To elucidate this process, four Specific Aims are proposed for years 25-29 of this grant. The experiments will make extensive use of """"""""Fluorophore-Assisted Carbohydrate Electrophoresis"""""""" (FACE), which we adapted for a comprehensive """"""""one-stop shopping"""""""" view of the LLO pool, its substrates, and both its N-glycoprotein and degradation products.
Aim I will identify the sensor and effector of M6P, i.e. the proteins that receive M6P's signal, and that carry out M6P's specific instructions for LLO destruction.
Aim II will elucidate an unprecedented biosynthetic pathway for M6P 2nd messengers. This pathway is activated by the stress of viral infection, and is distinct from conventional pathways involved in synthesis of M6P as a metabolic precursor.
Aim III will identify ER stress-activated components of the pathway.
Aim I V will test the effect of M6P signaling on viral infectivity using herpes simplex virus-1 (HSV1). A critical prediction of Aim IV is that M6P signaling will inhibit HSV1 replication. The work will illustrate novel evolutionary aspects of anti-viral defense, and reformat long-standing dogma involving glycogen metabolism. A path for future experiments on the role of M6P signaling in viral pathogenesis and disease will be paved, leading to new anti-viral drugs and treatments.
Infections by pathogenic viruses such as HIV, flu, herpes, and West Nile virus are major health problems in the USA. Treatment of such infections in the clinic is often difficult, with unacceptable frequencies of illness and death. This project will exploit a novel Achilles Heel of such viruses, based upon their requirement for carbohydrate, leading to future development of new anti-viral medicines and treatments.
|DeRossi, Charles; Vacaru, Ana; Rafiq, Ruhina et al. (2016) trappc11 is required for protein glycosylation in zebrafish and humans. Mol Biol Cell 27:1220-34|
|Hasan, Maroof; Fermaintt, Charles S; Gao, Ningguo et al. (2015) Cytosolic Nuclease TREX1 Regulates Oligosaccharyltransferase Activity Independent of Nuclease Activity to Suppress Immune Activation. Immunity 43:463-74|
|Leclerc, Guy J; DeSalvo, Joanna; Du, Jianfeng et al. (2015) Mcl-1 downregulation leads to the heightened sensitivity exhibited by BCR-ABL positive ALL to induction of energy and ER-stress. Leuk Res :|
|Lehrman, Mark A (2015) Flipping a Lipid-Linked Oligosaccharide? You Must Whip It! Trends Biochem Sci 40:715-7|
|Philips, Katherine B; Kurtoglu, Metin; Leung, Howard J et al. (2014) Increased sensitivity to glucose starvation correlates with downregulation of glycogen phosphorylase isoform PYGB in tumor cell lines resistant to 2-deoxy-D-glucose. Cancer Chemother Pharmacol 73:349-61|
|Wang, Zhao V; Deng, Yingfeng; Gao, Ningguo et al. (2014) Spliced X-box binding protein 1 couples the unfolded protein response to hexosamine biosynthetic pathway. Cell 156:1179-92|
|Jelk, Jennifer; Gao, Ningguo; Serricchio, Mauro et al. (2013) Glycoprotein biosynthesis in a eukaryote lacking the membrane protein Rft1. J Biol Chem 288:20616-23|
|Deng, Yingfeng; Wang, Zhao V; Tao, Caroline et al. (2013) The Xbp1s/GalE axis links ER stress to postprandial hepatic metabolism. J Clin Invest 123:455-68|
|Chu, Jaime; Mir, Alexander; Gao, Ningguo et al. (2013) A zebrafish model of congenital disorders of glycosylation with phosphomannose isomerase deficiency reveals an early opportunity for corrective mannose supplementation. Dis Model Mech 6:95-105|
|Gao, Ningguo; Lehrman, Mark A (2013) Mannose-6-phosphate: a regulator of LLO destruction. Methods Mol Biol 1022:277-82|
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