Single-cell RNA-Seq analysis reveals dual sensing of HIV-1 in blood Axl+ dendritic cells

Sensing of incoming viruses represents one of the pivotal tasks of dendritic cells (DC). Human primary blood DC encompass various subsets that are diverse in their susceptibility and response to HIV-1. The recent identification of Axl+DC, a new blood DC subset, endowed with unique capacities to bind, replicate, and transmit HIV-1 prompted us to evaluate its anti-viral response. We show that HIV-1 induced two main broad and intense transcriptional programs in different Axl+DC potentially induced by different sensors; a NF-κB-mediated program that led to DC maturation and efficient antigen-specific CD4+T cell activation, and a program mediated by STAT1/2 that activated type I IFN and an ISG response. These responses were absent from cDC2 exposed to HIV-1 except when viral replication occurred. Finally, Axl+DC actively replicating HIV-1 identified by quantification of viral transcripts exhibited a mixed NF-κB/ISG innate response. Our results suggest that the route of HIV-1 entry may dictate different innate sensing pathway by DC.

Differential Effect of SARS-CoV-2 Spike Glycoprotein 1 on Human Bronchial and Alveolar Lung Mucosa Models: Implications for Pathogenicity

Background: The SARS-CoV-2 spike protein mediates attachment of the virus to the host cell receptor and fusion between the virus and the cell membrane. The S1 subunit of the spike glycoprotein (S1 protein) contains the angiotensin converting enzyme 2 (ACE2) receptor binding domain. The SARS-CoV-2 variants of concern contain mutations in the S1 subunit. The spike protein is the primary target of neutralizing antibodies generated following infection, and constitutes the viral component of mRNA-based COVID-19 vaccines. Methods: Therefore, in this work we assessed the effect of exposure (24 h) to 10 nM SARS-CoV-2 recombinant S1 protein on physiologically relevant human bronchial (bro) and alveolar (alv) lung mucosa models cultured at air–liquid interface (ALI) (n= 6 per exposure condition). Corresponding sham exposed samples served as a control. The bro-ALI model was developed using primary bronchial epithelial cells and the alv-ALI model using representative type II pneumocytes (NCI-H441). Results: Exposure to S1 protein induced the surface expression of ACE2, toll like receptor (TLR) 2, and TLR4 in both bro-ALI and alv-ALI models. Transcript expression analysis identified 117 (bro-ALI) and 97 (alv-ALI) differentially regulated genes (p ≤ 0.01). Pathway analysis revealed enrichment of canonical pathways such as interferon (IFN) signaling, influenza, coronavirus, and anti-viral response in the bro-ALI. Secreted levels of interleukin (IL) 4 and IL12 were significantly (p < 0.05) increased, whereas IL6 decreased in the bro-ALI. In the case of alv-ALI, enriched terms involving p53, APRIL (a proliferation-inducing ligand) tight junction, integrin kinase, and IL1 signaling were identified. These terms are associated with lung fibrosis. Further, significantly (p < 0.05) increased levels of secreted pro-inflammatory cytokines IFNγ, IL1ꞵ, IL2, IL4, IL6, IL8, IL10, IL13, and tumor necrosis factor alpha were detected in alv-ALI, whereas IL12 was decreased. Altered levels of these cytokines are also associated with lung fibrotic response. Conclusions: In conclusion, we observed a typical anti-viral response in the bronchial model and a pro-fibrotic response in the alveolar model. The bro-ALI and alv-ALI models may serve as an easy and robust platform for assessing the pathogenicity of SARS-CoV-2 variants of concern at different lung regions.

A New Perspective of COVID-19 Infection: An Epigenetics Point of View

Coronavirus disease 2019 (COVID-2019) started in Wuhan, China, in December 2019. Angiotensin-converting enzyme 2 (ACE2) receptor was one of the most important genes related to the entrance of the virus to the host. Until now, several variations have been identified in ACE2 and related transmembrane protease serine 2. Epigenetic modifications not only play an important role during the maintenance of genome and cellular homoeostasis but also for the etiopathophysiology of the virus infection. Studies showed methylation of ACE2 was changed to depend on host and age of the host during the viral infection.In this study, we provide an epigenetics point of view to the coronavirus infection. We highlight the importance of epigenetic modifications during viral replication and infection and their interaction with COVID-19 susceptibility and host viral response.

RNF126 is a positive regulator of TRAF3 ubiquitination

Ubiquitination and de-ubiquitination of signaling molecules are critical regulatory mechanisms in various biological contexts such as inflammatory signaling and the DNA damage response. Thus, finely tuned regulation of protein ubiquitination is essential for maintaining cellular homeostasis. Here, we showed that the RING finger protein RNF126 interacts with TRAF3 and promotes its K63-linked poly-ubiquitination, which is a crucial step in the TRAF3-dependent anti-viral response. We found that RNF126 also interacts with OTUB1, a deubiquitinating enzyme that negatively regulates K63-linked ubiquitination of TRAF3. RNF126 promotes ubiquitination of OTUB1, leading to reduced deubiquitinating activity towards TRAF3. Moreover, RNF126 promotes ubiquitination of OTUB1 on cysteine 91, which is reportedly required for its catalytic activity. Taken together, our results suggest that RNF126 positively regulates the anti-viral response by directly promoting K63-linked poly-ubiquitination of TRAF3 and by reducing OTUB1 activity.

The effect of nucleos(t)ide analogues on clinical outcomes of patients treated with transarterial chemoembolization and radiofrequency ablation for hepatitis B virus-related hepatocellular carcinoma

Background/Aims: Because hepatitis B virus (HBV) replication has been known to play animportant role in cancer recurrence after curative treatment of HBV-related hepatocellularcarcinoma (HCC), we examined whether treatment based on nucleos(t)ide analogues (NAs)might decrease the recurrence rate and improve patient survival.Methods: The retrospective cohort study enrolled 73 patients with chronic hepatitis B whowere treated with transarterial chemoembolization (TACE) and radiofrequency ablation (RFA)with curative intent for HCC. Among those, 30 and 43 patients were treated with tenofovirdisoproxil fumarate (TDF) and entecavir (ETV), respectively.Results: Of the 73 patients, 51 experienced HCC recurrence, and 14 patients were deadduring a follow-up of 73±34 months. Multivariate analyses showed that tumor size (hazardratio [HR], 1.590; 95% confidence-interval [CI], 1.106-2.285; P=0.012) and Child-Pugh class B(vs. class A/non cirrhosis; HR, 5.794; 95% CI, 2.311-14.523; P=0.001) was significantly associatedwith HCC recurrence, and Child-Pugh class B (HR, 7.357; 95% CI, 2.100-25.777; P=0.002) was anindependent unfavorable prognostic factor for survival. During NAs therapy, TDF was superiorto ETV for complete viral response at 1 year after the date of combination of TACE and RFA(P=0.016). However, the risks of HCC recurrence and survival were not significantly differentbetween those treated with TDF versus ETV.Conclusions: TDF was superior to ETV for achieving complete viral response. However, therecurrence and mortality after TACE and RFA for HBV-related HCC were not significantlydifferent between patients treated with TDF versus ETV.

Cap-independent translation and a precisely localized RNA sequence enable SARS-CoV-2 to control host translation and escape anti-viral response

Translation of SARS-CoV-2-encoded mRNAs by the host ribosomes is essential for its propagation. Following infection, the early expressed viral protein NSP1 binds the ribosome, represses translation and induces mRNA degradation, while the host elicits an anti-viral response. The mechanisms enabling viral mRNAs to escape this multifaceted repression remain obscure. Here we show that expression of NSP1 leads to destabilization of multi-exon cellular mRNAs, while intron-less transcripts, such as viral mRNAs and anti-viral interferon genes, remain relatively stable. We identified a conserved and precisely located cap-proximal RNA element devoid of guanosines that confers resistance to NSP1-mediated translation inhibition. Importantly, the primary sequence rather than the secondary structure is critical for protection. We further show that the genomic 5'UTR of SARS-CoV-2 exhibits an IRES-like activity and promotes expression of NSP1 in an eIF4E-independent and Torin-1 resistant manner. Upon expression, NSP1 enhances cap-independent translation. However, the sub-genomic 5'UTRs are highly sensitive to eIF4E availability, rendering viral propagation partially sensitive to Torin-1. The combined NSP1-mediated degradation of spliced mRNAs and translation inhibition of single-exon genes, along with the unique features present in the viral 5'UTRs, ensure robust expression of viral mRNAs. These features can be exploited as potential therapeutic targets.

LONG-TERM HEALTH OUTCOME AMONG HCV PATIENTS WITH ADVANCED LIVER FIBROSIS TREATED THROUGH HCV ELIMINATION PROGRAM IN GEORGIA

Goal: The main objective of our study was to evaluate the effect of long-term treatment in patients with high liver fibrosis who have achieved a sustainable viral response (SVR) after receiving direct antiviral medication (DAA). Assess sociodemographic characteristics and clinical /laboratory data role in changing the level of liver fibrosis. The Methods: study cohort included patients from the Hepatitis C Elimination Program treated with direct antiviral drugs (DAA), with high-grade elastography-determined liver fibrosis (> = F3), and patients with a FIB4 score above 3.25 and sustainable viral response is achieved within 12-24 weeks after completion of treatment. The study group was selected retrospectively from Clinic Neolab's medical database and records. A total of 150 patients were studied. Data were processed in the statistical program SPSS24. The Wilcoxon Signed Ranks test was used from the statistical tests.Results: The study was conducted in 2020. These data were determined both before and after treatment. After treatment on the metavir scale, liver damage levels improved in 51.7% of patients.Statistical analysis showed that the change in fibrosis level after treatment was statistically significant (P <0.001). The study normalized data from laboratory studies such as Alt (85,3%) and Ast (80 5%).