Molecular mechanisms underlying SARS-CoV-2 hepatotropism and liver damage

In coronavirus disease 2019(COVID-19),severe acute respiratory syndrome coronavirus-2(SARS-CoV-2)primarily targets the respiratory system,but evidence suggests extrapulmonary organ involvement,notably in the liver.Viral RNA has been detected in hepatic tissues,and in situ hybridization revealed virions in blood vessels and endothelial cells.Electron microscopy confirmed viral particles in hepatocytes,emphasizing the need for understanding hepatotropism and direct cytopathic effects in COVID-19-related liver injury.Various factors contribute to liver injury,including direct cytotoxicity,vascular changes,inflammatory responses,immune reactions from COVID-19 and vaccinations,and druginduced liver injury.Although a typical hepatitis presentation is not widely documented,elevated liver biochemical markers are common in hospitalized COVID-19 patients,primarily showing a hepatocellular pattern of elevation.Long-term studies suggest progressive cholestasis may affect 20%of patients with chronic liver disease post-SARS-CoV-2 infection.The molecular mechanisms underlying SARS-CoV-2 infection in the liver and the resulting liver damage are complex.This“Editorial”highlights the expression of the Angiotensin-converting enzyme-2 receptor in liver cells,the role of inflammatory responses,the impact of hypoxia,the involvement of the liver's vascular system,the infection of bile duct epithelial cells,the activation of hepatic stellate cells,and the contribution of monocyte-derived macrophages.It also mentions that pre-existing liver conditions can worsen the outcomes of COVID-19.Understanding the interaction of SARS-CoV-2 with the liver is still evolving,and further research is required.

Perilipin 2 inhibits replication of hepatitis B virus deoxyribonucleic acid by regulating autophagy under high-fat conditions

Hepatitis B virus(HBV)infection poses a global health concern without a definitive cure;however,antiviral medications can effectively suppress viral replication.This study delves into the intricate interplay between lipid metabo-lism and HBV replication,implicating molecular mechanisms such as the stearoyl coenzyme A desaturase 1 autophagy pathway,SAC1-like phosphatidylinositol phosphatase,and galectin-9 mediated selective autophagy of viral core proteins in regulating HBV replication.Within lipid droplets,perilipin 2(PLIN2)emerges as a pivotal guardian,with its overexpression protecting against autophagy and downregulation stimulating triglyceride catabolism through the autophagy pathway.This editorial discusses the correlation between hepatic steatosis and HBV replication,emphasizing the role of PLIN2 in this process.The study underscores the multifaceted roles of lipid metabolism,autophagy,and perilipins in HBV replication,shedding light on potential therapeutic avenues.

Editorial:Metabolomics in chronic hepatitis C:Decoding fibrosis grading and underlying pathways

In the management of the growing population of hepatitis C virus-infected patients,a significant clinical challenge exists in determining the most effective methods for assessing liver impairment.The prognosis and treatment of chronic hepatitis C depend,in part,on the evaluation of histological activity,specifically cell necrosis and inflammation,and the extent of liver fibrosis.These parameters are traditionally obtained through a liver biopsy.However,liver biopsy presents both invasiveness and potential sampling errors,primarily due to inadequate biopsy size.To circumvent these issues,several non-invasive markers have been proposed as alternatives for diagnosing liver damage.Different imaging techniques and blood parameters as single markers or combined with clinical information are included.This Editorial discusses the identification of a set of six distinctive lipid metabolites in every fibrosis grade that appear to show a pronounced propensity to create clusters among patients who share the same fibrosis grade,thereby demonstrating enhanced efficacy in distinguishing between the different grades.

Core promoter: A critical region where the hepatitis B virus makes decisions

The core promoter(CP)of the viral genome plays an important role for hepatitis B virus(HBV)replication as it directs initiation of transcription for the synthesis of both the precore and pregenomic(pg)RNAs.The CP consists of the upper regulatory region and the basal core promoter(BCP).The CP overlaps with the 3’-end of the X open reading frames and the 5’-end of the precore region,and contains cis-acting elements that can independently direct transcription of the precore mRNA and pgRNA.Its transcription regulation is under strict control of viral and cellular factors.Even though this regulatory region exhibits high sequence conservation,when variations appear,they may contribute to the persistence of HBV within the host,leading to chronic infection and cirrhosis,and eventually,hepatocellular carcinoma.Among CP sequence variations,those occurring at BCP may dysregulate viral gene expression with emphasis in the hepatitis B e antigen,and contribute to disease progression.In this review these molecular aspects and pathologic topics of core promoter are deeply evaluated.

CD4+ T cells and natural killer cells: Biomarkers for hepatic fibrosis in human immunodeficiency virus/hepatitis C virus-coinfected patients

AIM To characterize peripheral blood natural killer(NK) cells phenotypes by flow cytometry as potential biomarker of liver fibrosis in human immunodeficiency virus(HIV)/hepatitis C virus(HCV) coinfected patients.METHODS Peripheral mononuclear cells from 24 HIV/HCV(HBVnegative) coinfected and 5 HIV/HCV/HBV seronegative individuals were evaluated. HIV/HCV coinfected patients were divided in to groups: G1, patients with METAVIR F0-F2 and G2, patients with METAVIR F3-F4. NK surface cell staining was performed with: AntiCD3(APC/Cy7), anti-CD56(PE/Cy5), anti-CD57(APC), anti-CD25(PE), anti-CD69(FITC), anti-NKp30(PE), antiNKp46(PE/Cy7), anti-NKG2D(APC), anti-DNAM(FITC); anti-CD62L(PE/Cy7), anti-CCR7(PE), anti-TRAIL(PE), anti-Fas L(PE), anti CD94(FITC). Flow cytometry data acquisition was performed on BD FACSCanto, analyzed using Flow Jo software. Frequency of fluorescence was analyzed for all single markers. Clinical records were reviewed, and epidemiological and clinical data were obtained.RESULTS Samples from 11 patients were included in G1 and from 13 in G2. All patients were on ARV, with undetectable HIV viral load. Liver fibrosis was evaluated by transient elastography in 90% of the patients and with biopsy in 10% of the patients. Mean HCV viral load was(6.18 ± 0.7 log10). Even though, no major significant differences were observed between G1 and G2 regarding NK surface markers, it was found that patients with higher liver fibrosis presented statistically lower percentage of NK cells than individual with low to mild fibrosis and healthy controls(G2: 5.4% ± 2.3%, G1: 12.6% ± 8.2%, P = 0.002 and healthy controls 12.2% ± 2.7%, P = 0.008). It was also found that individuals with higher liver fibrosis presented lower CD4 LT count than those from G1(G2: 521 ± 312 cells/μL, G1: 770 ± 205 cells/μL; P = 0.035).CONCLUSION Higher levels of liver fibrosis were associated with lower percentage of NK cells and LTCD4+ count; and they may serve as noninvasive biomarkers of liver damage.

Molecular mechanisms implicated in SARS-CoV-2 liver tropism

The coronavirus disease 2019(COVID-19)pandemic is caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).Hepatic involvement is common in SARS-CoV-2-infected individuals.It is currently accepted that the direct and indirect hepatic effects of SARS-CoV-2 infection play a significant role in COVID-19.In individuals with pre-existing infectious and non-infectious liver disease,who are at a remarkably higher risk of developing severe COVID-19 and death,this pathology is most medically relevant.This review emphasizes the current pathways regarded as contributing to the gastrointestinal and hepatic ailments linked to COVID-19-infected patients due to an imbalanced interaction among the liver,systemic inflammation,disrupted coagulation,and the lung.

Are the mechanisms involved in astrocyte and lymphocyte death during HIV infection similar?

Acquired immune deficiency syndrome is associated with the death of CD4+ T lymphocytes. The entry of the human immunodeficiency virus (HIV) into the central nervous system leads to a broad spectrum of HIV-associated neurocognitive disorders (HAND) ranging from mild to severe dementia. Inside the central nervous system, HIV establishes infection in astrocytes - the predominant cell type in the brain, thus causing neuropathology, but the underlying mechanisms remain unknown.