Host Viral Infection Research Articles

Viral Evasion of the Interferon System

Viral Evasion of the Interferon System

13 Viral control of phytoplankton

Viral control of phytoplankton Virus ecology is a young rapidly developing field that is changing our understanding of the functioning of marine ecosystems. Viruses are known to be ubiquitous, numerically dominant members of the aquatic microbial communities, infecting a wide spectrum of hosts, including planktonic microalgae. They are typically host‐specific agents of mortality and thus likely influence the dynamics and succession of phytoplankton. As well, viral infection can have major biogeochemical implications through cell lysis and the resulting transformation of released POM into DOM. Bloom forming algal species with their high cell abundance may allow a rapid propagation of lytic viruses, resulting in a direct and significant controlling impact of viruses on bloom dynamics. Besides the concentration of host and virus, other potential factors influencing the quantitative importance of viral control of phytoplankton are resistance of host strains to virus infection (host range), variations in morphotypes of the phytoplankton species, the type of limiting nutrient, and variables affecting the fate of viruses (UV, grazing, adsorption to aggregates). The current presentation will provide examples of viral infected phytoplankton and will address some of the processes involved in viral mediated mortality of microalgae.

Necrotizing vasculitis and ulcerative colitis.

Abstract Objectives Two of the main target tissues of SARS-coronavirus 2 are the oral cavity pharynx-larynx epithelium, the main virus entry site, and the lung epithelium. The virus enters host cells through binding of the Spike protein to ACE2 receptor and subsequent S priming by the TMPRSS2 protease. Herein we aim to assess differences in both ACE2 and TMPRSS2 expression in normal tissues from oral cavity-pharynx-larynx and lung tissues as well as neoplastic tissues from the same histological areas. The information provided in this study may contribute to better understanding of SARS-coronavirus 2 ability to interact with different biological systems and contributes to cumulative knowledge on potential mechanisms to inhibit its diffusion. Materials and Methods The study has been conducted using The Cancer Genome Atlas (TCGA) and the Regina Elena Institute (IRE) databases and validated by experimental model in HNSCC and Lung cancer cells. Data from one COVID19 positive patient who was operated on for HNSCC was also included. We have analyzed 478 tumor samples and 44 normal samples from TCGA HNSCC cohort for whom both miRNA and mRNA sequencing was available. The dataset included 391 HPV- and 85 HPV+ cases, with 331 P53 mutated and 147 P53 wild type cases respectively. 352 out of 478 samples were male and 126 female. In IRE cohort we analyzed 66 tumor samples with matched normal sample for miRNA profiling and 23 tumor\normal matched samples for mRNA profiling. 45 out of 66 tumors from IRE cohort were male and 21 female, 38 were P53 mutated and 27 wild type. Most patients (63 of 66) in IRE cohort were HPV negative. Normalized TCGA HNSCC gene expression and miRNA expression data were obtained from Broad Institute TCGA Genome Data Analysis Center (http://gdac.broadinstitute.org/). mRNA expression data from IRE cohort used in this study has been deposited to NCBI’s Gene Expression Omnibus and is accessible through GEO series accession number GSE107591. In order to inference about potential molecular modulation of TMPRSS2, we also included miRNAs expression for the 66 IRE cohort matched tumor and normal samples from Agilent platform. DNA methylation data for TCGA tumors were obtained from Wanderer (http://maplab.imppc.org/wanderer/). We used miRWalk and miRNet web tools for miRNA-target interaction prediction and pathway enrichment analysis. The correlation and regression analyses as well as the miRNA and gene modulation and the survival analysis were conducted using Matlab R2019. Results TMPRSS2 expression in HNSCC was significantly reduced compared to the normal tissues and had a prognostic value in HNSCC patients. Reduction of TMPRSS2 expression was more evident in women than in men, in TP53 mutated versus wild TP53 tumors as well as in HPV negative patients compared to HPV positive counterparts. Functionally, we assessed the multivariate effect on TMPRSS2 in a single regression model. We observed that all variables had an independent effect on TMPRSS2 in HNSCC patients with HPV negative, TP53 mutated status and with elevated TP53-dependent Myc-target genes associated with low TMPRSS2 expression. Investigation of the molecular modulation of TMPRSS2 in both HNSCC and lung cancers revealed that expression of microRNAs targeting TMPRSS2 anti-correlated in both TCGA and IRE HNSCC datasets, while there was not evidence of TMPRSS2 promoter methylation in both tumor cohorts. Interestingly, the anti-correlation between microRNAs and TMPRSS2 expression was corroborated by testing this association in a SARS-CoV-2 positive HNSCC patient. Conclusions Collectively, these findings suggest that tumoral tissues, herein exemplified by HNSCC and lung cancers might be more resistant to SARS-CoV-2 infection due to reduced expression of TMPRSS2. The protective mechanism might occur, at least partially, through the aberrant activation of TMPRSS2 targeting microRNAs; thereby providing strong evidence on the role of non-coding RNA molecule in host viral infection. These observations may help to better assess the frailty of SARS-CoV-2 positive cancer patients.