Recurrent herpes, due to reactivation of herpes simplex virus type 1 (HSV-1) from latency in the trigeminal ganglia (TG) can cause herpes simplex encephalitis (HSE) and herpes stromal keratitis (HSK). HSE is the most common cause of sporadic lethal encephalitis in immune competent individuals. Similarly, HSK is the most common cause of corneal blindness due to an infectious agent. The HSV-1 latency associated transcript (LAT), the only viral gene abundantly expressed during latency, is involved in both the virus'neurovirulence and its reactivation phenotype, since various mutants within this genomic locus affect one or the other or both. Our long term goal is to understand the molecular mechanisms behind HSV-1 neurovirulence, latency, and reactivation, which should lead to improved clinical therapies directed against herpes encephalitis and corneal blindness. Recently, 8 """"""""LAT"""""""" microRNAs (miRNAs) were reported. Most overlap important viral genes known to affect neurovirulence and/or reactivation. In addition, some of the miRNAs affect expression of these genes. We hypothesize that LAT miRNAs influence neurovirulence and/or the reactivation phenotype. Testing this hypothesis requires construction of LAT miRNA KO mutants, which is complicated by the fact that the miRNA sequences overlap critical HSV-1 genes. Simple deletion of the miRNA sequences would disrupt these viral genes and significantly impact viral functions unrelated to the miRNAs. By making use of codon redundancy to not alter the amino acid sequence of an overlapping gene, we changed 21 of the 75 nts in one of the precursor miRNAs (the H2 miRNA). This was done on both a wt (LAT(+)) and a LAT(-) genomic background. The H2 KO mutants expressed no H2 miRNA. In preliminary studies both H2 KO mutants had increased neurovirulence in mice, and the LAT(-) H2 KO mutant also had increased reactivation. Reactivation results for the wt-H2 KO are not yet available. These preliminary studies strongly suggest that the H2 miRNA is normally involved in decreasing HSV-1 neurovirulence and reactivation. We also found that the LAT miRNAs do not require the LAT promoter for their expression, suggesting that one or more LAT miRNAs may account for LAT promoter deletion mutants'ability to still support some reactivation. If, as expected, we find that one or more of the LAT miRNAs significantly affects neurovirulence (or the spontaneous reactivation phenotype), manipulation of those miRNAs would be a useful target for future clinical interventions.
Our Specific Aims i nclude: 1) Test the hypothesis that LA miRNAs influence HSV-1 neurovirulence by constructing LAT miRNA KO mutants and analyzing them in vivo. 2) Test the hypothesis that the LAT miRNAs influence the HSV-1 reactivation phenotype. 3) Test the hypothesis that the mechanism(s) by which LAT miRNAs influence neurovirulence and/or reactivation is to alter expression of viral genes involved in neurovirulence and reactivation.
Recurrent herpes simplex virus type 1 (HSV-1) can cause herpes simplex encephalitis (HSE), the most common cause of sporadic lethal encephalitis in immune competent individuals, and herpes stromal keratitis (HSK), the most common cause of corneal blindness due to an infectious agent in developed countries. We have strong preliminary results showing that at least one of the newly discovered HSV-1 LAT miRNAs acts to increase HSV-1 neurovirulence and also alters virus reactivation. This proposal is directed at confirming this finding and determining if other HSV-1 LAT miRNAs also alter HSV-1 neurovirulence and/or spontaneous reactivation, and if so investigating the mechanism(s). The knowledge gained here will be critical for the longer term goal of developing efficacious therapeutic clinical interventins to prevent or decrease herpes simplex encephalitis and herpes stromal keratitis. page 1of 1
|Perng, Guey-Chuen; Osorio, Nelson; Jiang, Xianzhi et al. (2016) Large Amounts of Reactivated Virus in Tears Precedes Recurrent Herpes Stromal Keratitis in Stressed Rabbits Latently Infected with Herpes Simplex Virus. Curr Eye Res 41:284-91|
|Jester, James V; Morishige, Naoyuki; BenMohamed, Lbachir et al. (2016) Confocal Microscopic Analysis of a Rabbit Eye Model of High-Incidence Recurrent Herpes Stromal Keratitis. Cornea 35:81-8|
|Jiang, Xianzhi; Brown, Don; Osorio, Nelson et al. (2016) Increased neurovirulence and reactivation of the herpes simplex virus type 1 latency-associated transcript (LAT)-negative mutant dLAT2903 with a disrupted LAT miR-H2. J Neurovirol 22:38-49|
|Srivastava, Ruchi; Dervillez, Xavier; Khan, Arif A et al. (2016) The Herpes Simplex Virus Latency-Associated Transcript Gene Is Associated with a Broader Repertoire of Virus-Specific Exhausted CD8+ T Cells Retained within the Trigeminal Ganglia of Latently Infected HLA Transgenic Rabbits. J Virol 90:3913-28|
|Jiang, Xianzhi; Brown, Don; Osorio, Nelson et al. (2015) A herpes simplex virus type 1 mutant disrupted for microRNA H2 with increased neurovirulence and rate of reactivation. J Neurovirol 21:199-209|
|Carpenter, Dale; Hsiang, Chinhui; Jiang, Xianzhi et al. (2015) The herpes simplex virus type 1 (HSV-1) latency-associated transcript (LAT) protects cells against cold-shock-induced apoptosis by maintaining phosphorylation of protein kinase B (AKT). J Neurovirol 21:568-75|
|Srivastava, Ruchi; Khan, Arif A; Spencer, Doran et al. (2015) HLA-A02:01-restricted epitopes identified from the herpes simplex virus tegument protein VP11/12 preferentially recall polyfunctional effector memory CD8+ T cells from seropositive asymptomatic individuals and protect humanized HLA-A*02:01 transgenic mice J Immunol 194:2232-48|
|Khan, Arif A; Srivastava, Ruchi; Spencer, Doran et al. (2015) Phenotypic and functional characterization of herpes simplex virus glycoprotein B epitope-specific effector and memory CD8+ T cells from symptomatic and asymptomatic individuals with ocular herpes. J Virol 89:3776-92|
|BenMohamed, Lbachir; Osorio, Nelson; Srivastava, Ruchi et al. (2015) Decreased reactivation of a herpes simplex virus type 1 (HSV-1) latency-associated transcript (LAT) mutant using the in vivo mouse UV-B model of induced reactivation. J Neurovirol 21:508-17|