Activation of CXCL-8 Transcription by Hepatitis E Virus ORF-1 via AP-1

Viral Hepatitis: Host Immune Interaction, Pathogenesis and New Therapeutic Strategies

Viral hepatitis is a major cause of liver illness worldwide. Despite advances in the understanding of these infections, the pathogenesis of hepatitis remains a complex process driven by intricate interactions between hepatitis viruses and host cells at the molecular level. This paper will examine in detail the dynamics of these host-pathogen interactions, highlighting the key mechanisms that regulate virus entry into the hepatocyte, their replication, evasion of immune responses, and induction of hepatocellular damage. The unique strategies employed by different hepatitis viruses, such as hepatitis B, C, D, and E viruses, to exploit metabolic and cell signaling pathways to their advantage will be discussed. At the same time, the innate and adaptive immune responses put in place by the host to counter viral infection will be analyzed. Special attention will be paid to genetic, epigenetic, and environmental factors that modulate individual susceptibility to different forms of viral hepatitis. In addition, this work will highlight the latest findings on the mechanisms of viral persistence leading to the chronic hepatitis state and the potential implications for the development of new therapeutic strategies. Fully understanding the complex host-pathogen interactions in viral hepatitis is crucial to identifying new therapeutic targets, developing more effective approaches for treatment, and shedding light on the mechanisms underlying progression to more advanced stages of liver damage.

Interplay between Hepatitis E Virus and Host Cell Pattern Recognition Receptors

Hepatitis E virus (HEV) usually causes self-limiting acute hepatitis, but the disease can become chronic in immunocompromised individuals. HEV infection in pregnant women is reported to cause up to 30% mortality, especially in the third trimester. Additionally, extrahepatic manifestations like neuronal and renal diseases and pancreatitis are also reported during the course of HEV infection. The mechanism of HEV pathogenesis remains poorly understood. Innate immunity is the first line of defense triggered within minutes to hours after the first pathogenic insult. Growing evidence based on reverse genetics systems, in vitro cell culture models, and representative studies in animal models including non-human primates, has implicated the role of the host’s innate immune response during HEV infection. HEV persists in presence of interferons (IFNs) plausibly by evading cellular antiviral defense. This review summarizes our current understanding of recognizing HEV-associated molecular patterns by host cell Pattern Recognition Receptors (PRRs) in eliciting innate immune response during HEV infection as well as mechanisms of virus-mediated immune evasion.

PBRM1 regulates proliferation and the cell cycle in renal cell carcinoma through a chemokine/chemokine receptor interaction pathway

PBRM1 is a novel tumor suppressor gene that can inhibit cancer cell proliferation and predict the outcome of renal cell carcinoma (RCC), but its biological role needs further elucidation. We examined expression of the PBRM1 gene in RCC cell lines and the effect of PBRM1 on cell proliferation and cell cycle in RCC ACHN cells. Microarray processing and analysis was used to explore novel pathways involved in tumorigenesis related to PBRM1 knockdown. PBRM1 was expressed at high levels in RCC ACHN cells and lentivirus-mediated PBRM1 knockdown in these cells caused an increase in the proportion of cells in S phase of the cell cycle and promoted in vitro proliferation and migration. In vivo experiments showed that downregulation of PBRM1 promoted tumorigenesis in nude mice. In pathway gene chip analysis, the chemokine/chemokine receptor interaction pathway showed the greatest difference in gene expression upon PBRM1 knockdown. Protein levels of IL6ST and CCL2 were increased, whereas levels of interleukin (IL)-8, IL-6, and CXCL2 were decreased, in knockdown cells. Re-expression of IL-8 in PBRM1 knockdown ACHN cells could significantly decrease cell proliferation/migration and induced cell arrest in the G2/M phase. These findings indicate that PBRM1 alters cell cycle progression and inhibits proliferation and migration of ACHN cells through the chemokine/chemokine receptor pathway.

ORF3 as a sensitive and specific diagnostic index for hepatitis E

We explored the significance of the expression of hepatitis E virus (HEV) open reading frame 3 (ORF3) in hepatitis E rat models. We also investigated its diagnostic value. Forty Sprague-Dawley (SD) rats were infected with HEV and 10 uninfected rats were selected for the control group. Rats were sacrificed at 14, 21, 35 and 70 days after infection. They were divided into 4 groups: Model group 1, model group 2, model group 3 and model group 4. ORF3 protein expression level in liver tissue, level of adipokines [fatty acid synthase (FAS), tissue inhibitor of metalloproteinase-2 (TIMP-2) and angiotensin-converting enzyme inhibitor 2 (ACE-2)], Th1/Th2 cells balance [interferon (IFN), interleukin-4 (IL-4) and Th1/Th2] and the level of immune outcome (levels of CD4⁺, CD8⁺ T lymphocytes and CD4⁺/CD8⁺) were measured and compared among groups. Our results showed that HEV IgG and HEV RNA levels in the model group 3 were higher than those in the other 3 groups. Compared with the control group, expression level of ORF3 protein in the liver tissue as well as Fas and TIMP levels were significantly higher in the model group 3. ACE-2 level was significantly lower than that of the control group (P<0.05). In the model group 3, IFN-γ, IL-4 and Th1/Th2 levels were meaningfully higher than those of the control group. CD4⁺ T lymphocytes and CD4⁺/CD8⁺ ratio were obviously lower than those in the control group (P<0.05). The expression level of ORF3 was positively correlated with levels of Fas, TIMP-2 and Th1/Th2. It was negatively correlated with ACE-2 and CD4⁺/CD8⁺ levels (P<0.05). We concluded that ORF3 expression level was directly related to severity and prognosis, and that ORF3 protein can be considered as a sensitive and specific diagnostic index.

Hepatitis E virus infection: Epidemiology and treatment implications

Hepatitis E virus (HEV) infection is now established as an emerging enteric viral hepatitis. Standard treatments in acute and chronic hepatitis E remain to be established. This study undertakes a review of the epidemiology, treatment implication and vaccine prevention from published literature. HEV infection is a worldwide public health problem and can cause acute and chronic hepatitis E. HEV genotypes 1 and 2 are primarily found in developing countries due to waterborne transmission, while the zoonotic potential of genotypes 3 and 4 affects mostly industrialized countries. An awareness of HEV transmission through blood donation, especially in the immunocompromised and solid organ transplant patients, merits an effective anti-viral therapy. There are currently no clear indications for the treatment of acute hepatitis E. Despite concerns for side effects, ribavirin monotherapy or in combination with pegylated interferon alpha for at least 3 mo appeared to show significant efficacy in the treatment of chronic hepatitis E. However, there are no available treatment options for specific patient population groups, such as women who are pregnant. Vaccination and screening of HEV in blood donors are currently a global priority in managing infection. New strategies for the treatment and control of hepatitis E are required for both acute and chronic infections, such as prophylactic use of medications, controlling large outbreaks, and finding acceptable antiviral therapy for pregnant women and other patient groups for whom the current options of treatment are not viable.