Absence of PEXEL-Dependent Protein Export in Plasmodium Liver Stages Cannot Be Restored by Gain of the HSP101 Protein Translocon ATPase

Host cell remodeling is critical for successful Plasmodium replication inside erythrocytes and achieved by targeted export of parasite-encoded proteins. In contrast, during liver infection the malarial parasite appears to avoid protein export, perhaps to limit exposure of parasite antigens by infected liver cells. HSP101, the force-generating ATPase of the protein translocon of exported proteins (PTEX) is the only component that is switched off during early liver infection. Here, we generated transgenic Plasmodium berghei parasite lines that restore liver stage expression of HSP101. HSP101 expression in infected hepatocytes was achieved by swapping the endogenous promoter with the ptex150 promoter and by inserting an additional copy under the control of the elongation one alpha (ef1α) promoter. Both promoters drive constitutive and, hence, also pre-erythrocytic expression. Transgenic parasites were able to complete the life cycle, but failed to export PEXEL-proteins in early liver stages. Our results suggest that PTEX-dependent early liver stage export cannot be restored by addition of HSP101, indicative of alternative export complexes or other functions of the PTEX core complex during liver infection.

Beyond the Usual Suspects: Hepatitis E Virus and Its Implications in Hepatocellular Carcinoma

Hepatitis E virus infections are the leading cause of viral hepatitis in humans, contributing to an estimated 3.3 million symptomatic cases and almost 44,000 deaths annually. Recently, HEV infections have been found to result in chronic liver infection and cirrhosis in severely immunocompromised patients, suggesting the possibility of HEV-induced hepatocarcinogenesis. While HEV-associated formation of HCC has rarely been reported, the expansion of HEV’s clinical spectrum and the increasing evidence of chronic HEV infections raise questions about the connection between HEV and HCC. The present review summarizes current clinical evidence of the relationship between HEV and HCC and discusses mechanisms of virus-induced HCC development with regard to HEV pathogenesis. We further elucidate why the development of HEV-induced hepatocellular carcinoma has so rarely been observed and provide an outlook on possible experimental set-ups to study the relationship between HEV and HCC formation.

Excreted Trypanosoma brucei proteins inhibit Plasmodium hepatic infection

Malaria, a disease caused by Plasmodium parasites, remains a major threat to public health globally. It is the most common disease in patients with sleeping sickness, another parasitic illness, caused by Trypanosoma brucei. We have previously shown that a T. brucei infection impairs a secondary P. berghei liver infection and decreases malaria severity in mice. However, whether this effect requires an active trypanosome infection remained unknown. Here, we show that Plasmodium liver infection can also be inhibited by the serum of a mouse previously infected by T. brucei and by total protein lysates of this kinetoplastid. Biochemical characterisation showed that the anti-Plasmodium activity of the total T. brucei lysates depends on its protein fraction, but is independent of the abundant variant surface glycoprotein. Finally, we found that the protein(s) responsible for the inhibition of Plasmodium infection is/are present within a fraction of ~350 proteins that are excreted to the bloodstream of the host. We conclude that the defence mechanism developed by trypanosomes against Plasmodium relies on protein excretion. This study opens the door to the identification of novel antiplasmodial intervention strategies.

Infection of Human Cells by SARS-CoV-2 and Molecular Overview of Gastrointestinal, Neurological, and Hepatic Problems in COVID-19 Patients

The gastrointestinal tract is the body’s largest interface between the host and the external environment. People infected with SARS-CoV-2 are at higher risk of microbiome alterations and severe diseases. Recent evidence has suggested that the pathophysiological and molecular mechanisms associated with gastrointestinal complicity in SARS-CoV-2 infection could be explained by the role of angiotensin-converting enzyme-2 (ACE2) cell receptors. These receptors are overexpressed in the gut lining, leading to a high intestinal permeability to foreign pathogens. It is believed that SARS-CoV-2 has a lesser likelihood of causing liver infection because of the diminished expression of ACE2 in liver cells. Interestingly, an interconnection between the lungs, brain, and gastrointestinal tract during severe COVID-19 has been mentioned. We hope that this review on the molecular mechanisms related to the gastrointestinal disorders as well as neurological and hepatic manifestations experienced by COVID-19 patients will help scientists to find a convenient solution for this and other pandemic events.

The Role of Serum microRNA (hsa-miR-519d) And the Associated Target Gene (SQSTM1) As Diagnostic Biological Molecular Biomarkers for Hepatocellular Carcinoma

Background Hepatocellular carcinoma (HCC) is the most common primary liver cancer. The mortality of liver cancer worldwide is ranked as fourth between other cancer causes in males and females. In Egypt, it is a major problem due to the high prevalence of Hepatitis C Virus infection. Objective To characterize the expression of new serum non-coding RNA microRNA (hsa-miR519d) and the associated target gene (SQSTM1) to evaluate their usefulness as diagnostic molecular biomarkers for HCC. Patients and Methods we assessed the expression of the microRNA (hsa-miR-519d-3p) and the mRNA of (SQSTM1) gene in serum samples from 50 participants: (34) HCC patients, (11) chronic liver infection patients and (5) normal volunteers, using Quantitative Real Time Polymerase Chain Reaction (qPCR). Results The results of both microRNA (miR-519d-3p) and mRNA of (SQSTM1) gene showed a significant upregulation of their serum level in the HCC group in comparison to chronic liver infection group. In addition, the results of the serum microRNA (miR-519d) and the messenger RNA of (SQSTM1) gene using receiver operating characteristic (ROC) curve showed higher sensitivity and specificity than that of AFP, as it was (91.2%-81.8%), (97.1%-100%) and (76.5%72.7%) respectively. Conclusion The serum microRNA (hsa-mir-519d-3p) and the serum mRNA of its targeted gene (SQSTM1) are both significantly upregulated in the serum of Hepatocellular carcinoma (HCC) patients. And that the (hsa-mir-519d-3p) stimulates the gene (SQSTM1) at the transcriptional level. Finally, we could conclude that the serum microRNA (hsa-mir-519d-3p) and the serum mRNA of (SQSTM1) gene can be used as diagnostic biomarkers for HCC with good sensitivity and specificity even for early stages of HCC in comparison with AFP.

Pre-Existing HBV and HCV Infections Do Not Affect COVID-19-Related Outcomes: An Observational Retrospective Study

Background: A better understanding of the interaction between SARS-CoV-2 infection and HBV or HCV hepatitis is very important. Objectives: We aimed at determining the prevalence and the impact of pre-existing HBV and HCV infections in patients with COVID-19. Methods: We conducted a retrospective study and included all the subjects positive for SARS-CoV-2 from March to May 2020. We evaluated the prevalence of chronic HBV and HCV infections and performed a matched cohort analysis to compare COVID-19-related outcomes between patients with and without infections due to HBV or HCV. Results: Among 606 subjects, 12 cases (2%) had positive HBsAg, and 6 cases (0.99%) presented detectable HCV RNA. We recognized 80 individuals positive for SARS-CoV-2 with negative markers for HBV and HCV suitable for the matched analysis. No statistical differences in mechanical ventilation and mortality rates were found (P = 0.27 and P = 0.80, respectively). Moreover, individuals with viral hepatitis were more likely to be admitted to the Intensive Care Unit in comparison to those without HBV or HCV infections (29% vs. 15%). The median time of virus clearance was 27.5 days, with no difference between the two groups. Conclusions: In our cohort, the pre-existing viral liver infection did not have any impact on the clinical and virological evolution of COVID-19.

Screening of viral-vectored P. falciparum pre-erythrocytic candidate vaccine antigens using chimeric rodent parasites

To screen for additional vaccine candidate antigens of Plasmodium pre-erythrocytic stages, fourteen P. falciparum proteins were selected based on expression in sporozoites or their role in establishment of hepatocyte infection. For preclinical evaluation of immunogenicity of these proteins in mice, chimeric P. berghei sporozoites were created that express the P. falciparum proteins in sporozoites as an additional copy gene under control of the uis4 gene promoter. All fourteen chimeric parasites produced sporozoites but sporozoites of eight lines failed to establish a liver infection, indicating a negative impact of these P. falciparum proteins on sporozoite infectivity. Immunogenicity of the other six proteins (SPELD, ETRAMP10.3, SIAP2, SPATR, HT, RPL3) was analyzed by immunization of inbred BALB/c and outbred CD-1 mice with viral-vectored (ChAd63 or ChAdOx1, MVA) vaccines, followed by challenge with chimeric sporozoites. Protective immunogenicity was determined by analyzing parasite liver load and prepatent period of blood stage infection after challenge. Of the six proteins only SPELD immunized mice showed partial protection. We discuss both the low protective immunogenicity of these proteins in the chimeric rodent malaria challenge model and the negative effect on P. berghei sporozoite infectivity of several P. falciparum proteins expressed in the chimeric sporozoites.

Investigation and Prevalence of Hepatitis C Virus Genotypes in Pregnant Women

ABSTRACT Hepatitis C virus (HCV) causes severe liver infection and is spread through blood transmission from infected person to healthy individuals. HCV is more common in less developed countries due to poor hygienic conditions. This condition can be worse in pregnant women, where HCV can infect the fetus and may lead to chronic infections and may cause cirrhosis and carcinoma. Therefore, the purpose of this research was to study the distribution and prevalence of HCV in pregnant women in the Pakistani population, where such data are unavailable. Blood from 72 HCV-positive pregnant women was collected, RNA was extracted and nested PCR was performed for genotyping using genotypespecific primers. The most frequent genotype was found to be 3a (79%), followed by 3b (4%), 1a (4%), 1b (2%) and mixed genotypes (2%). The severity of HCV, reaction to therapy, and prognosis depend on several factors and one of the most important factors is genotype. Hence, this study will pave the way for the adoption of efficient therapeutic models to control HCV in high-risk populations.