Correlation between COVID-19 and hepatitis B: A systematic review.

BACKGROUND: There is growing evidence that patients with coronavirus disease 2019 (COVID-19) frequently present with liver impairment. Hepatitis B virus (HBV) remains a major public health threat in current society. Both severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and HBV can cause liver damage, and current findings on whether HBV infection increases disease severity in COVID-19 patients are inconsistent, and whether SARS-CoV-2 infection accelerates hepatitis B progression or leads to a worse prognosis in hepatitis B patients has not been adequately elucidated. AIM: To explore the complex relationship between COVID-19 and hepatitis B in order to inform the research and management of patients co-infected with SARS-CoV-2 and HBV. METHODS: An experienced information specialist searched the literature in the following online databases: PubMed, China National Knowledge Infrastructure, Google Scholar, Scopus, Wiley, Web of Science, Cochrane, and ScienceDirect. The literature published from December 2019 to September 1, 2022 was included in the search. We also searched medRxiv and bioRxiv for gray literature and manually scanned references of included articles. Articles reporting studies conducted in humans discussing hepatitis B and COVID-19 were included. We excluded duplicate publications. News reports, reports, and other gray literature were included if they contained quantifiable evidence (case reports, findings, and qualitative analysis). Some topics that included HBV or COVID-19 samples but did not have quantitative evidence were excluded from the review. RESULTS: A total of 57 studies were eligible and included in this review. They were from 11 countries, of which 33 (57.9%) were from China. Forty-two of the 57 studies reported abnormalities in liver enzymes, three mainly reported abnormalities in blood parameters, four indicated no significant liver function alterations, and another eight studies did not provide data on changes in liver function. Fifty-seven studies were retrospective and the total number of co-infections was 1932, the largest sample size was 7723, and the largest number of co-infections was 353. Most of the studies suggested an interaction between hepatitis B and COVID-19, while 12 studies clearly indicated no interaction between hepatitis B and COVID-19. Six of the 57 studies clearly reported HBV activation. Six studies were related to liver transplant patients. CONCLUSION: There is some association between COVID-19 and hepatitis B. Future high-quality randomized trials are needed to further elucidate the interaction between COVID-19 and hepatitis B.

Syngeneic homograft of framework regions enhances the affinity of the mouse anti-human epidermal receptor 2 single-chain antibody e23sFv.

e23sFv is a HER2-targeted single-chain variable fragment (scFV) that was characterized as the targeting portion of a HER2-targeted tumour proapoptotic molecule in our previous study. In vitro antibody affinity maturation is a method to enhance antibody affinity either by complementarity-determining region (CDR) mutagenesis or by framework region (FR) engraftment. In the present study, the affinity of e23sFv was enhanced using two strategies. In one approach, site-directed mutations were introduced into the FRs of e23sFv (designated EMEY), and in the other approach e23sFv FRs were substituted with FRs from the most homologous screened antibodies (designated EX1 and EX2). Notably, EX1 derived from the FR engraftment strategy demonstrated a 4-fold higher affinity for HER2 compared with e23sFv and was internalized into HER2-overexpressing cells; however, EMEY and EX2 exhibited reduced affinity for HER2 and decreased internalization potential compared with EX1. The 3D structure of EX1 and the HER2-EX1 complex was acquired using molecular homology modelling and docking and the HER2 epitopes of EX1 and the molecular interaction energy of the EX1-HER2 complex were predicted. In the present study, it was demonstrated that scFv affinity improvement based on sequence alignment was feasible and effective. Moreover, the FR grafting strategy was indicated to be more effective and simple compared with site-directed mutagenesis to improve e23sFv affinity. In conclusion, it was indicated that the affinity-improved candidate EX1 may present a great potential for the diagnosis and treatment of HER2-overexpressing tumours.

The effect of direct translocation across endosomes on the cytotoxicity of the recombinant protein e23sFv-Fdt-casp6 to HER2 positive gastric cancer cells.

HER2-positive cancers represent a class of malignancies with high metastasis and poor prognosis. We previously generated the e23sFv-PEA II-casp6 recombinant, which contains an anti-HER2 single-chain antibody (e23sFv), a Pseudomonas exotoxin A translocation domain (PEA II), and a constitutively active caspase-6 (casp6), and demonstrated its potent selective anti-tumor activities. In this study, we generated a smaller-sized recombinant e23sFv-Fdt-casp6, in which the PEA II domain was replaced with the furin cleavage sequence from diphtheria toxin (Fdt), and explored its translocation pathway and specific killing mechanism. We found that e23sFv-Fdt-casp6 proteins, following their receptor-mediated endocytosis in HER2-positive gastric cancer cells, underwent furin-mediated cleavage in endosome and engaged in direct translocation of the released C-terminal fragment (active caspase-6) instead of via the trans-Golgi and the endoplasmic reticulum (ER) pathway. The active caspase-6 cleaved its well-documented substrate, Lamin A, and subsequently triggered the apoptosis of cancer cells. The e23sFv-Fdt-casp6 proteins produced from genetically modified cells showed a selective cytotoxicity to cultured HER2-positive gastric cancer cells. Similar to the results of our previous research on e23sFv-PEA II-casp6, the delivery of liposome-encapsulated e23sFv-Fdt-casp6 constructs in tumor-adjacent muscles also inhibited tumor growth and prolonged animal survival in a nude mouse xenograft tumor model. Moreover, e23sFv-Fdt-casp6 proteins were also cytotoxic to trastuzumab-resistant gastric cancer cells characterized by downregulated HER2 expression. Accordingly, e23sFv-Fdt-casp6 recombinant provides a promising therapeutic alternative for HER2-positive and trastuzumab-resistant gastric cancers.

[Expression of a chimeric gene containing poly-arginine as the protein transduction domain and its killing activity against HER2 positive gastric cancer SGC-7901 cells].

AIM: To construct a eukaryotic expression vector for chimeric gene containing poly-arginine as the protein transduction domain(PTD) and transiently transfect this vector into HER2 positive SGC-7901 cells and HER2 negative HeLa cells to examine its effect on cell growth. METHODS: PCR amplication was used to obtain the gene of active form caspase-3 fused with nonaarginine, and then fusion gene was cloned into eukaryotic expression vector containing e23sFv DNA fragment. After this chimeric gene transfected into SGC-7901 cells and HeLa cells by Lipofectamine 2000™; reagent, indirect immunofluorescence and cell counting were used to examine the expression in these two cells and the effect on cell growth. RESULTS: The eukaryotic expression vector, named pCMV-e23sFv-R9;-casp3, encoding e23sFv/caspase-3 containing nonaarginine as the PTD was successfully constructed. e23sFv- R9;-casp3 protein was expressed in a secretary manner in both SGC-7901 cells and HeLa cells. Transfected SGC-7901 cells were found obvious growth inhibitory, morphology change and condensed nucleus, whereas neither growth inhibitory nor apparent morphology change was detected in transfected HeLa cells. CONCLUSION: Of the secretary expressed chimeric protein, the antibody moiety against HER2 can mediate targeted recognition, the nonaarginine translocating peptide can promote activation and translocation of the effector molecule, and the active caspase-3 can effectively induce cell killing.

Enhanced treatment of articular cartilage defect of the knee by intra-articular injection of Bcl-xL-engineered mesenchymal stem cells in rabbit model.

Direct intra-articular injection of mesenchymal stem cells (MSCs) has been proposed as a potential cell therapy for cartilage defects. This cell therapy relies on the survival of the implanted MSCs. However, the arduous local environment may limit cell viability after implantation, which would restrict the cells' regenerative capacity. Thus, it is necessary to reinforce the implanted cells against the unfavourable microenvironment in order to improve the efficacy of cell therapy. We examined whether the transduction of an anti-apoptotic protein, Bcl-xL, into MSCs could prevent cell death and improve the implantation efficiency of MSCs in a rabbit model. Our current findings demonstrate that the group treated with Bcl-xL-engineered MSCs could improve cartilage healing both morphologically and histologically when compared with the controls. These results suggest that intra-articular injection of Bcl-xL-engineered MSCs is a potential non-invasive therapeutic method for effectively treating cartilage defects of the knee.

Recombinant immunoproapoptotic proteins with furin site can translocate and kill HER2-positive cancer cells.

We previously reported the selective killing of HER2-positive tumor cells by a class of immunoproapoptotic proteins containing single-chain antibody, translocation domain of Pseudomonas exotoxin A (domain II; PEA II), and constitutively active human apoptotic molecules. In this study, a novel class of antitumor immunoproapoptotic proteins was explored to mediate tumor-specific apoptosis both in vitro and in vivo. Three furin cleavage sequences, including a synthetic polyarginine tract, and two furin cleavable sequences from PEA and diphtheria toxin were respectively used to replace PEA II in the previously constructed immunoproapoptotic protein. When produced and secreted by the genetically modified Jurkat cells, the novel targeted proapoptotic proteins selectively bound to HER2, which is often overexpressed on tumor cell surface. Followed by receptor-mediated endocytosis and furin cleavage in the endosome, the recombinant proteins could translocate into the cytosol, leading to irreversible cell death. Moreover, delivery of these proteins by either i.m. plasmid injection or i.v. injection of plasmid-expressing Jurkat cells led to tumor regression and prolonged animal survival in a nude mouse xenograft tumor model, indicating in vivo antitumor activity of the recombinant proteins. We conclude that the new class of immunoproapoptotic proteins show comparable activity with PEA II-containing counterpart and provide an attractive therapeutic alternative as they contain much less exogenous fragments.

[Study on apoptosis of human cervical carcinoma HeLa cells with RNA interference targeting hTERT].

AIM: To study the induction of tumor cell apoptosis by RNA interference-mediated inhibition of the expression of telomerase in cancer cells. METHODS: HeLa cells were transfected with the successfully established siRNA(small interfering RNA) expression vectors targeting hTERT (human telomerase reverse transcriptase). By electronic microscopy, Western blot and FCM (flow cytometry), the apoptosis of HeLa cells was tested. RESULTS: The established siRNA expression vectors could induce apoptosis of HeLa cells. CONCLUSION: Transfection of siRNA expression vectors targeting hTERT can induce apoptosis of HeLa cells.