How severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infections engage cellular host pathways and innate immunity in infected cells remains largely elusive. We performed an integrative proteo-transcriptomics analysis in SARS-CoV-2 infected Huh7 cells to map the cellular response to the invading virus over time. We identified four pathways, ErbB, HIF-1, mTOR and TNF signaling, among others that were markedly modulated during the course of the SARS-CoV-2 infection in vitro. Western blot validation of the downstream effector molecules of these pathways revealed a dose-dependent activation of Akt, mTOR, S6K1 and 4E-BP1 at 24 hours post infection (hpi). However, we found a significant inhibition of HIF-1α through 24hpi and 48hpi of the infection, suggesting a crosstalk between the SARS-CoV-2 and the Akt/mTOR/HIF-1 signaling pathways. Inhibition of the mTOR signaling pathway using Akt inhibitor MK-2206 showed a significant reduction in virus production. Further investigations are required to better understand the molecular sequelae in order to guide potential therapy in the management of severe coronavirus disease 2019 (COVID-19) patients.

Viruses hijack host metabolic pathways for their replicative advantage. In this study, using patient-derived multi-omics data and in vitro infection assays, we aimed to understand the role of key metabolic pathways that can regulate severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) reproduction and their association with disease severity. We used multi-omics platforms (targeted and untargeted proteomics and untargeted metabolomics) on patient samples and cell line models along with immune phenotyping of metabolite transporters in patient blood to understand viral-induced metabolic modulations. We also modulated key metabolic pathways that were identified using multi-omics data to regulate the viral reproduction in vitro . COVID-19 disease severity was characterized by increased plasma glucose and mannose levels. Immune phenotyping identified altered expression patterns of carbohydrate transporter, GLUT1, in CD8 + T-cells, intermediate and non-classical monocytes, and amino acid transporter, xCT, in classical, intermediate, and non-classical monocytes. In in vitro lung epithelial cell (Calu-3) infection model we found that glycolysis and glutaminolysis are essential for virus replication and blocking these metabolic pathways caused significant reduction in virus production. Taken together, we therefore hypothesized that SARS-CoV-2 utilizes and rewires pathways governing central carbon metabolism leading to the efflux of toxic metabolites and associated with disease severity. Thus, the host metabolic perturbation could be an attractive strategy to limit the viral replication and disease severity.

The commonly used laboratory cell lines are the first line of experimental models to study the pathogenicity and performing antiviral assays for emerging viruses. Here, we assessed the tropism and cytopathogenicity of the first Swedish isolate of SARS-CoV-2 in six different human cell lines, compared their growth characteristics and performed quantitative proteomics for the susceptible cell lines. Overall, Calu-3, Caco2, Huh7, and 293FT cell lines showed a high to moderate level of susceptibility to SARS-CoV-2. In Caco2 cells the virus can achieve high titers in the absence of any prominent cytopathic effect. The protein abundance profile during SARS-CoV-2 infection revealed cell-type-specific regulation of cellular pathways. Type-I interferon signaling was identified as the common dysregulated cellular response in Caco2, Calu-3 and Huh7 cells. Together, our data shows cell-type specific variability for cytopathogenicity, susceptibility and cellular response to SARS-CoV-2 and provide important clues to guide future studies.

The N-terminal domains of the herpesvirus large tegument proteins encode a conserved cysteine protease with ubiquitin- and NEDD8-specific deconjugase activity. The proteins are expressed during the productive virus cycle and are incorporated into infectious virus particles, being delivered to the target cells upon primary infection. Members of this viral enzyme family were shown to regulate different aspects of the virus life cycle and the innate anti-viral response. However, only few substrates have been identified and the mechanisms of these effects remain largely unknown. In order to gain insights on the substrates and signaling pathways targeted by the viral enzymes, we have used co-immunoprecipitation and mass spectrometry to identify cellular proteins that interact with the Epstein-Barr virus encoded homologue BPLF1. Several members of the 14-3-3-family of scaffold proteins were found amongst the top hits of the BPLF1 interactome, suggesting that, through this interaction, BPLF1 may regulate a variety of cellular signaling pathways. Analysis of the shared protein-interaction network revealed that BPLF1 promotes the assembly of a tri-molecular complex including, in addition to 14-3-3, the ubiquitin ligase TRIM25 that participates in the innate immune response via ubiquitination of cytosolic pattern recognition receptor, RIG-I. The involvement of BPLF1 in the regulation of this signaling pathway was confirmed by inhibition of the type-I IFN responses in cells transfected with a catalytically active BPLF1 N-terminal domain or expressing the endogenous protein upon reactivation of the productive virus cycle. We found that the active viral enzyme promotes the dimerization and autoubiquitination of TRIM25. Upon triggering of the IFN response, RIG-I is recruited to the complex but ubiquitination is severely impaired, which functionally inactivates the RIG-I signalosome. The capacity to bind to and functionally inactivate the RIG-I signalosome is shared by the homologues encoded by other human herpesviruses.

Though more importance is being given to HIV-TB coinfection, we cannot overlook DM, which showed a significantly higher prevalence in pulmonary TB patients compared to HIV. The rising prevalence of DM in high TB burden countries may adversely affect TB control.

The 14-3-3 molecular scaffolds promote type I interferon (IFN) responses by stabilizing the interaction of RIG-I with the TRIM25 ligase. Viruses have evolved unique strategies to halt this cellular response to support their replication and spread. Here, we report that the ubiquitin deconjugase (DUB) encoded in the N-terminus of the Epstein-Barr virus (EBV) large tegument protein BPLF1 harnesses 14-3-3 molecules to promote TRIM25 autoubiquitination and sequestration of the ligase into inactive protein aggregates. Catalytically inactive BPLF1 induced K48-linked autoubiquitination and degradation of TRIM25 while the ligase was mono- or di-ubiquitinated in the presence of the active viral enzyme and formed cytosolic aggregates decorated by the autophagy receptor p62/SQSTM1. Aggregate formation and the inhibition of IFN response were abolished by mutations of solvent exposed residues in helix-2 of BPLF1 that prevented binding to 14-3-3 while preserving both catalytic activity and binding to TRIM25. 14-3-3 interacted with the Coiled-Coil (CC) domain of TRIM25 in in vitro pulldown, while BPLF1 interacted with both the CC and B-box domains, suggesting that 14-3-3 positions BPLF1 at the ends of the CC dimer, close to known autoubiquitination sites. Our findings provide a molecular understanding of the mechanism by which a viral deubiquitinase inhibits the IFN response and emphasize the role of 14-3-3 proteins in modulating antiviral defenses.

Root canal sealers that possess good antimicrobial property can prevent residual and recurrent infection and contribute to successful endodontic therapy. This study evaluated the antimicrobial activity of four endodontic sealers, AH Plus, Tubliseal EWT, EndoRez, and iRoot SP, against three different microorganisms, E. faecalis, C. albicans, and S. aureus, by direct contact test. 10 μL microbial suspensions were allowed to directly contact the four endodontic sealers for 1 hr at 37°C. Subsequently microbial growth was measured spectrophotometrically every 30 min for 18 hours. The microbial suspensions were simultaneously tested to determine the antimicrobial effect of components which are capable of diffusing into the medium. The results revealed that AH Plus and iRootSP had significantly higher antimicrobial activity against E. faecalis. AH Plus and Tubliseal EWT showed significantly higher antimicrobial activity against C. albicans and S. aureus compared to iRoot SP and EndoRez. EndoRez showed the least antimicrobial activity against all the three microorganisms. Inhibition of microbial growth is related to the direct contact of microorganisms with the sealers. In conclusion AH Plus had significantly higher antimicrobial activity against E. faecalis, C. albicans, and S. aureus.

Summaryobjective To determine the frequency of underlying risk factors and the socio-economic impact based on occupation in the development of tuberculosis. results Diabetes mellitus (DM) (30.9%) was the most prevalent condition and significantly more common than other risk factors like smoking (16.9%), alcoholism (12.6%), HIV (10.6%), malignancy (5.8%), chronic liver diseases (3.9%), history of contact with TB (3.4%), chronic corticosteroid therapy (2.9%), chronic kidney diseases and malnourishment (1.5%). There were 82 patients (39.6%) with no underlying risk factor. Men (M:F = 3.7:1) and patients older than 40 years had a higher incidence of co-existing conditions. PTB was significantly more common in blue-collar (44%) and white-collar (27.1%) workers than household workers (12.1%), students (10.6%) and retired ⁄ unemployed people (6.3%).conclusion Pulmonary tuberculosis had a significant impact and predominated in male patients coexisting with DM. Patients with DM and suggestive pulmonary symptoms should be screened for tuberculosis. More stringent health education and awareness programme should be implemented at the grass root level. Although more focus is being given on TB-HIV coinfection as a major concern for public health, there are other underlying risk factors which compromise the immune status. Diabetes mellitus (DM) widely impairs neutrophil and macrophage functions (Ljubic et al. 2004) and thus can be a major aggravating risk factor for TB.