Role of Ferroptosis in the Progression of COVID-19 and the Development of Long COVID.

OBJECTIVES: To examine the role of ferroptosis on the pathogenesis and progression of COVID-19. MATERIALS AND METHODS: A total of 127 patients who were hospitalized for COVID-19 were categorized into two groups according to the intensity of oxygen therapy (high-flow or low-flow). Clinical characteristics, laboratory parameters, plasma markers, and peripheral blood mononuclear cell (PBMC) markers were measured at baseline and one or two weeks after treatment. Telephone follow-up was performed 3 months after discharge to assess long COVID. RESULTS: Patients receiving high-flow oxygen therapy had greater levels of neutrophils; D-dimer; C reactive protein; procalcitonin; plasma protein levels of tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6), IL-17, and acyl-CoA synthetase long-chain family member 4 (ACSL4); and PBMC mRNA level of TNF-α; but had lower levels of lymphocytes and plasma glutathione peroxidase 4 (GPX4). There were negative correlations of plasma GPX4 and cystine/glutamate transporter-11 (SLC7A11) with TNF-α, IL-6, and IL-17, and positive correlations of ACSL4 with inflammatory markers in plasma and PBMCs. The plasma levels of TNF-α, IL-6, IL-17, and ACSL4 were significantly lower after treatment than at baseline, but there were higher post-treatment levels of lymphocytes, GPX4, and SLC7A11. Patients with long COVID had a lower baseline level of plasma SLC7A11. CONCLUSION: Ferroptosis is activated during the progression of COVID-19, and a low baseline level of a ferroptosis marker (SLC7A11) may indicate an increased risk for long COVID-19. Ferroptosis has potential as a clinical indicator of long COVID and as a therapeutic target.

Inhibiting apoptosis and GSDME-mediated pyroptosis attenuates hepatic injury in septic mice.

BACKGROUND: Sepsis is characterized by severe inflammation and organ dysfunction resulting from a dysregulated organismal response to infection. Although pyroptosis has been presumably shown to be a major cause of multiple organ failure and septic death, whether gasdermin E (GSDME)-mediated pyroptosis occurs in septic liver injury and whether inhibiting apoptosis and GSDME-mediated pyroptosis can attenuate septic liver injury remain unclear. This study investigated the role of apoptosis and GSDME-mediated pyroptosis in septic liver injury. METHODS: Adult male C57BL/6 mice were randomly divided into four groups: sham, cecal ligation puncture (CLP), CLP + Z-DEVD-FMK (a caspase-3 inhibitor, 5 mg/kg), and CLP + Ac-DMLD-CMK (a GSDME inhibitor, 5 mg/kg). Sepsis severity was assessed using the murine sepsis score (MSS). Hepatic tissue damage was observed by the hematoxylin-eosin staining method, the activities of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST), the levels of malondialdehyde (MDA), the concentrations of interleukin-1ß (IL-1ß), and tumor necrosis factor-α (TNF-α) were measured according to the related kits, and the changes in the hepatic tissue reactive oxygen species (ROS) levels were detected by immunofluorescence (IF). The protein expression levels of cleaved caspase-3, GSDME-N, IL-1ß, B-cell lymphoma-2 (Bcl-2), cytochrome C (Cyt-c), and acetaldehyde dehydrogenase 2 (ALDH2) were detected using western blotting. GSDME expression was detected by immunohistochemistry. RESULTS: Compared with the Sham group, CLP mice showed high sepsis scores and obvious liver damage. However, in the CLP + Z-DEVD-FMK and CLP + Ac-DMLD-CMK groups, the sepsis scores were reduced and liver injury was alleviated. Compared with the Sham group, the serum ALT and AST activities, MDA and ROS levels, and IL-1ß and TNF-α concentrations were increased in the CLP group, as well as the protein expression of cleaved caspase-3, GSDME-N, IL-1ß, Cyt-c, and GSDME positive cells (P < 0.05). However, the expression levels of Bcl-2 and ALDH2 protein were decreased (P < 0.05). Compared with the CLP group, the CLP + Z-DEVD-FMK and CLP + Ac-DMLD-CMK groups showed low sepsis scores, ALT and AST activities, MDA and ROS levels, decreased IL-1ß and TNF-α concentrations, and decreased expression of cleaved caspase-3, GSDME-N, IL-1ß protein expression, and GSDME positive cells (P < 0.05). The expression levels of Bcl-2 and ALDH2 protein were increased (P < 0.05). CONCLUSION: Apoptosis and GSDME-mediated pyroptosis are involved in the development of sepsis-induced hepatic injury. Inhibition of apoptosis and GSDME-mediated pyroptosis attenuates injury. ALDH2 plays a protective role by inhibiting apoptosis and pyroptosis.

[Activation of Yes-associated protein (YAP) improves mouse acute liver failure by alleviating ferroptosis].

Objective To investigate the effects of YAP on the occurrence and progression of acute liver failure by regulating the ferroptosis pathway and its underlying mechanism. Methods A total of 20 8-week-old C57BL/6 mice were randomly divided into four groups: a control group, an acute liver failure model group, a YAP agonist XMU-MP-1 treatment group and a YAP inhibitor verteporfin treatment group, five mice for each group. HE staining was used to observe the pathological changes of hepatic inflammation and necrosis. Plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were detected by liver biochemistry. Iron (Fe), malondialdehyde (MDA), glutathione (GSH) determination kits were used to measure their levels in liver tissues of each group. The changes of hepatocyte mitochondrial in each group were observed by electron microscopy. Real time PCR and Western blot analysis were used to detect the mRNA and protein expressions of YAP, glutathione peroxidase 4 (GPX4) and 5-lipoxygenase (5-LOX). Results Compared with the control group, mice in the acute liver failure model group and the YAP inhibitor verteporfin treatment group showed severe liver tissue congestion with inflammatory cell infiltration and structural damage to hepatic lobules. Liver injury was alleviated in the XMU-MP-1 treatment group. With the occurrence of liver failure, plasma ALT and AST levels significantly increased, and liver function was improved in XMU-MP-1 treatment group. Electron microscopy showed that mitochondria in hepatocytes of mice with liver failure became smaller and bilayer membrane density increased, while mitochondria changes in the XMU-MP-1 group were alleviated. In addition, the acute liver failure model group showed an increase in Fe and MDA contents, decreased protein expressions of GPX4, and enhanced expression of 5-LOX, suggesting that ferroptosis was involved in acute liver failure in C57BL/6 mice. Ferroptosis was inhibited by activation of YAP. Conclusion Activation of YAP may ameliorate liver injury by inhibiting ferroptosis.

Sex differences in hepatocellular carcinoma indicated BEX4 as a potential target to improve efficacy of lenvatinib plus immune checkpoint inhibitors.

Background: Hepatocellular carcinoma (HCC) is the most common form of liver cancer, and significant sex disparities have been observed in HCC. We aim to explore the potential sex-biased mechanisms involved in hepatocarcinogenesis. Methods: Based on TCGA data, we compared clinical features, genetic alterations, and immune cell infiltrations between male and female HCC patients. In addition, we performed sex-based differential expression analysis and functional enrichment analysis. Finally, GSE64041 dataset and another HCC cohort were engaged to validate our findings. Results: Significant differences of genetic alterations and TME were observed between male and female HCC patients. Enhanced metabolism of lipids was associated with hepatocarcinogenesis in men, while ECM-organization-related pathways were correlated to HCC development in women. BEX4 was upregulated in female but downregulated in male HCC patients, and was positively correlated with immune checkpoint molecules and infiltrated immune cell. These findings were further validated in dataset GSE64041 and our HCC cohort. More importantly, a negative correlation was found between BEX4 expression and lenvatinib sensitivity. Conclusion: Distinct biological processes were involved in sex-biased tumorigenesis of HCC. BEX4 can be targeted to improve the efficacy of lenvatinib plus immune checkpoint inhibitors.

Identification of microRNA hsa-miR-30c-5p as an inhibitory factor in the progression of hepatocellular carcinoma and investigation of its regulatory network via comprehensive analysis.

Hepatocellular carcinoma (HCC) is a primary liver cancer with high morbidity and mortality. An increasing number of abnormal gene expressions were identified to be associated with the progression of HCC. Previous studies showed that the hsa-miR-30 c-5p (miR-30 c), one of the miR-30 family members, might play a role in suppressing tumor progression in a variety of tumors. The present study aims to examine miR-30 c effects in the development of HCC. The role of miR-30 c in HCC was comprehensively investigated by using bioinformatics and experiments in vitro. The multiple databases were combined to predict and screen the target genes and upstream lncRNAs of miR-30 c, and then constructed a competitive endogenous RNA (ceRNA) regulatory network with miR-30 c as the central miRNA. The miR-30 c-related ceRNA regulatory network was also initially validated in vitro. The results showed that miR-30 c over-expression could inhibit proliferation, migration, invasion, induce apoptosis, and increase G0/G1 phase ratio of HCC cells. Three miR-30 c upstream lncRNAs and 12 miR-30 c target genes were expressed in HCC cells with increased expression and poor prognosis, and a miR-30 C-related ceRNA regulatory network was constructed. This study verified miR-30 c as an inhibitory factor in the progression of HCC and performed analyses on the miR-30 c regulatory network, which might provide potential target information for HCC prognoses and therapies. However, further experiments in vivo and studies including clinical trials will be conducted to validate our results.

[Establishment of chimeric antigen receptor NK92MI cells recognizing HBsAg].

Objective To construct a lentiviral expression vector of chimeric antigen receptor (CAR) recognizing hepatitis B surface antigen (HBsAg) and make it expressed in NK92MI cells. Methods The CAR was designed and synthesized with the sequence of single chain variable fragment (scFv). Next it was cloned into a lentivirus expression vector, followed by packaging, concentration and titer determination. Then HEK293T cells were transduced with the concentrated lentivirus. The expression of CD3 zeta chain and the infection efficiency in the NK92MI cells were detected by Western blotting. Results The lentiviral expression vector of CAR for HBsAg recognition was successfully constructed, and the titer was ≥107 transducing units (TU)/mL. The expression of protein CD3zeta was verified in the NK92MI cells after infected with the lentiviral vector. Conclusion CAR-NK92MI cells recognizing HBsAg has been established successfully.

Comprehensive analysis of the MIR4435-2HG/miR-1-3p/MMP9/miR-29-3p/DUXAP8 ceRNA network axis in hepatocellular carcinoma.

A growing number of studies have shown that competitive endogenous RNA (ceRNA) regulatory networks might play important roles during the process of hepatocellular carcinoma (HCC). This study assessed the role of the ceRNA network in immune cell infiltration in HCC. Immune-related gene sets were downloaded from Molecular Signatures Database, and differentially expressed genes were screened based on TCGA HCC transcriptome data. The corresponding miRNAs with low expression and good prognostic implications, and the corresponding lncRNAs with high expression and poor prognostic were identified to construct ceRNA networks. The networks were utilized for clinical correlation analysis and risk model construction, and the CIBERSORT algorithm was applied to assess immune cell infiltration. In this study, the mRNA-miRNA-lncRNA model was used to construct a ceRNA network in HCC using immune-related differentially expressed mRNAs. Assessment of the MIR4435-2HG/hsa-miR-1-3p/MMP9/hsa-miR-29-3p/DUXAP8 ceRNA network axis in HCC showed that a high risk/poor prognosis was significantly correlated with tumor stage and invasion depth. MMP9 was positively correlated with resting M0 macrophages and NK cells and negatively correlated with activated mast cells, resting mast cells, monocytes and activated NK cells. DUXAP8 was positively correlated with M2 macrophages and negatively correlated with MIR4435-2HG, which was positively correlated with M2 macrophages and negatively correlated with activated mast cells, CD8 T cells and follicular helper T cells. The correlation of the MIR4435-2HG/hsa-miR-1-3p/MMP9/hsa-miR-29-3p/DUXAP8 ceRNA network axis with immune cell infiltration provides further information on the mechanism of HCC development. The result might improve our understanding the interactions between immune related genes and non-coding RNAs in the occurrence and development of HCC, and the relevant RNAs might be used as diagnostic and prognostic biomarkers and molecular targets in HCC patients.

[Establishment of STO Cell Lines Expressing Green Fluorescent Protein and Mouse Leukemia Inhibitory Factor].

OBJECTIVE: To establish the STO cell lines expressing green fluorescent protein (GFP) and mouse leukemia inhibitory factor (LIF) , and try to culture the mouse embryonic stem cells (mESCs) by using the established STO-GFP-mLIF cells as the feeder layer. METHODS: The lentiviral particles containing GFP and mLIF and puromycin-resistance gene were constructed and transduced into STO cell lines. The cell lines stably expressing GFP and mLIF genes were screened out. The expression level of the inserted exogenous LIF gene was tested by Western blot and ELISA. The STO-GFP-mLIF cells were treated with different concentrations of mitomycin C (5, 10, 15, 20 µg/ml) for different time (1.5, 2.5, 3, 3.5 hours) to prepare feeder layers and the cell proliferation level on feeder layer was observed. Mouse embryonic stem cells were cultured on mitomycin C-treated feeder layer and the growth of cell colonies was observed. RESULTS: The expression level of LIF protein in STO-GFP-mLIF cells was up-regulated, as compared with STO cells (P＜0.05). It was confirmed that the optimal concentration and time for inhibiting the proliferetion of STO-GFP-mLIF cells by mitomycin C were 10 µg/ml and 3 hours respectively. The observation also found that the embryonic stem cells could develop into typic "birdnest" shaped stem cell colony on mitomycin C-treated feeder layer. CONCLUSION: The stable STO cell lines effectively expressing green fluorescent protein and mouse leukemia inhibitory factor have been established successfully, which can maintain the undifferentiated state of mouse embryonic stem cells.

[Preparation and cytotoxic effects of scFv targeting human c-Met protein on lung adenocarcinoma A549 cells].

Objective To prepare and purify human single-chain variable fragment (scFv) targeting c-Met protein and identify its targeting to c-Met protein and its effects on lung adenocarcinoma cells. Methods The scFv gene was inserted into the pFuse vector to construct eukaryotic expression vector that expressed the Met-scFv fused with mouse Fc fragment. Met-scFv was purified by AKTA Protein Purification System and subjected to functional detection. ELISA was used to detect Met-scFv affinity. Flow cytometry and immunofluorescence staining were used to determine the recognition and binding ability of Met-scFv to lung adenocarcinoma cells. The impact of Met-scFv on the proliferation of A549 cells was evaluated by CCK-8 assay. The cytotoxic effect of Met-scFv on A549 cells was examined by the LDH release kit through CDC and ADCC assays. Results ELISA showed that Met-scFv had a dose-effect relationship with c-Met protein. Flow cytometry and immunofluorescence staining revealed that Met-scFv group signal was positive compared with the control group, which suggested that Met-scFv could specifically bind A549 cells. Met-scFv reduced the proliferation of A549 cells and had cytotoxicity to A549 cells, and the toxicity was positively correlated with the dose of Met-scFv. Conclusion Met-scFv targeting c-Met protein has been prepared and it can recognize and mediate to kill A549 cells in vitro.

An efficient model for auxiliary diagnosis of hepatocellular carcinoma based on gene expression programming.

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death worldwide. The early diagnosis of HCC is greatly helpful to achieve long-term disease-free survival. However, HCC is usually difficult to be diagnosed at an early stage. The aim of this study was to create the prediction model to diagnose HCC based on gene expression programming (GEP). GEP is an evolutionary algorithm and a domain-independent problem-solving technique. Clinical data show that six serum biomarkers, including gamma-glutamyl transferase, C-reaction protein, carcinoembryonic antigen, alpha-fetoprotein, carbohydrate antigen 153, and carbohydrate antigen 199, are related to HCC characteristics. In this study, the prediction of HCC was made based on these six biomarkers (195 HCC patients and 215 non-HCC controls) by setting up optimal joint models with GEP. The GEP model discriminated 353 out of 410 subjects, representing a determination coefficient of 86.28% (283/328) and 85.37% (70/82) for training and test sets, respectively. Compared to the results from the support vector machine, the artificial neural network, and the multilayer perceptron, GEP showed a better outcome. The results suggested that GEP modeling was a promising and excellent tool in diagnosis of hepatocellular carcinoma, and it could be widely used in HCC auxiliary diagnosis. Graphical abstract The process to establish an efficient model for auxiliary diagnosis of hepatocellular carcinoma.

Meta-analysis reveals an association between signal transducer and activator of transcription-4 polymorphism and hepatocellular carcinoma risk.

AIM: Hepatocellular carcinoma (HCC) is one of the most common causes of cancer-related mortality worldwide. Signal transducer and activator of transcription (STAT) proteins play a multitude of important functions in liver pathophysiology. Recent studies have indicated associations of rs7574865 single nucleotide polymorphism (SNP) in the STAT4 gene with various autoimmune diseases. The association between STAT4 polymorphism and the risk of HCC has been analyzed in several studies, but results remain inconsistent. This study used a meta-analysis approach to comprehensively investigate the correlation between STAT4 polymorphism and HCC risk based on previously published reports. METHODS: Studies were searched from the databases of PubMed, EMBase, Web of Science, and the Chinese National Knowledge Infrastructure up to 31 December 2015. The meta-analysis was carried out based on the statement of Preferred Reporting Items for Systematic Reviews and Meta-Analyses. RESULTS: Eight published studies, consisting of 7503 HCC patients (cases) and 13 831 individuals without HCC (controls), were included in the present study. Meta-analysis of the included studies revealed that STAT4 rs7574865 polymorphism contributed to the risk of HCC under all four genetic models, consisting of the allelic model (G vs. T: odds ratio [OR], 1.25; 95% confidence interval [CI], 1.19-1.30), the dominant effect model (GG + GT vs. TT: OR, 1.52; 95% CI, 1.26-1.84), the recessive effect model (GG vs. GT + TT: OR, 1.35; 95% CI, 1.21-1.50), and the co-dominant effect model (GG vs.. TT: OR, 1.72; 95% CI, 1.42-2.10) comparisons. No publication bias was indicated from either visualization of the funnel plot or Egger's test. CONCLUSION: A significantly increased risk of HCC associated with the rs7574865 G was found. The rs7574865 polymorphism might be used as one risk factor for HCC.

Evolution of wild type and mutants of the YMDD motif of hepatitis B virus polymerase during lamivudine therapy.

BACKGROUND AND AIM: Long-term lamivudine treatment for chronic hepatitis B virus (HBV) infection induces the emergence of lamivudine resistant HBV YMDD mutant strains. The aim of the present study was to observe the clone evolution of YMDD wild type and mutant strains in pretreatment and post-treatment samples during lamivudine therapy and analyze their clinical significance. METHODS: Ten serum samples (five before and five after 48 weeks of therapy) obtained from five patients chronically infected with HBV and treated with lamivudine were studied. Part of the HBV polymerase gene flanking the YMDD motif was sequenced after polymerase chain reaction (PCR) amplification. Meanwhile, 20-24 clones were selected at random from each sample and YMDD wild type and mutant strains were detected by real-time fluorimetry PCR established in our laboratory. RESULTS: The YMDD mutants were not detectable in all five patients before treatment and were found in four patients after 48 weeks of therapy by sequencing directly on PCR products. Analysis of individual clones showed that the ratios of mutant strains in each of the five patients were 0, 9.5, 0, 4.5 and 5.6%, respectively, before therapy and 100, 100, 65, 100 and 0%, respectively, after 48 weeks of therapy. M552I was detected before therapy in one patient but M552V became the domain strain after therapy. Until 52 weeks of therapy, serum HBV DNA and alanine aminotransferase (ALT) breakthrough were found in two of the four patients with YMDD mutations. The fifth patient experienced breakthrough of ALT but HBV DNA remained undetectable. CONCLUSIONS: The mutant strains of YMDD motif of HBV polymerase could be found in patients before lamivudine treatment, indicating that antiviral therapy allows the rapid selection of resistant strains. The replication ability of the M552V mutant strain might be stronger than that of the M552I mutant strain.