Exosome-derived circCCAR1 promotes CD8 + T-cell dysfunction and anti-PD1 resistance in hepatocellular carcinoma.

BACKGROUND: Circular RNAs (circRNAs) can be encapsulated into exosomes to participate in intercellular communication, affecting the malignant progression of a variety of tumors. Dysfunction of CD8 + T cells is the main factor in immune escape from hepatocellular carcinoma (HCC). Nevertheless, the effect of exosome-derived circRNAs on CD8 + T-cell dysfunction needs further exploration. METHODS: The effect of circCCAR1 on the tumorigenesis and metastasis of HCC was assessed by in vitro and in vivo functional experiments. The function of circCCAR1 in CD8 + T-cell dysfunction was measured by enzyme-linked immunosorbent assay (ELISA), western blotting and flow cytometry. Chromatin immunoprecipitation, biotinylated RNA pull-down, RNA immunoprecipitation, and MS2 pull-down assays were used to the exploration of mechanism. A mouse model with reconstituted human immune system components (huNSG mice) was constructed to explore the role of exosomal circCCAR1 in the resistance to anti-PD1 therapy in HCC. RESULTS: Increased circCCAR1 levels existed in tumor tissues and exosomes in the plasma of HCC patients, in the culture supernatant and HCC cells. CircCCAR1 accelerated the growth and metastasis of HCC in vitro and in vivo. E1A binding protein p300 (EP300) and eukaryotic translation initiation factor 4A3 (EIF4A3) promoted the biogenesis of circCCAR1, and Wilms tumor 1-associated protein (WTAP)-mediated m6A modification enhanced circCCAR1 stability by binding insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3). CircCCAR1 acted as a sponge for miR-127-5p to upregulate its target WTAP and a feedback loop comprising circCCAR1/miR-127-5p/WTAP axis was formed. CircCCAR1 is secreted by HCC cells in a heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNPA2B1)-dependent manner. Exosomal circCCAR1 was taken in by CD8 + T cells and caused dysfunction of CD8 + T cells by stabilizing the PD-1 protein. CircCCAR1 promoted resistance to anti-PD1 immunotherapy. Furthermore, increased cell division cycle and apoptosis regulator 1 (CCAR1) induced by EP300 promoted the binding of CCAR1 and ß-catenin protein, which further enhanced the transcription of PD-L1. CONCLUSIONS: The circCCAR1/miR-127-5p/WTAP feedback loop enhances the growth and metastasis of HCC. Exosomal circCCAR1 released by HCC cells contributes to immunosuppression by facilitating CD8 + T-cell dysfunction in HCC. CircCCAR1 induces resistance to anti-PD1 immunotherapy, providing a potential therapeutic strategy for HCC patients.

Immunological characteristics of human umbilical cord mesenchymal stem cells after hepatogenic differentiation.

BACKGROUND: Acute liver failure is one of the most intractable clinical problems. The use of bioartificial livers may solve donor shortage problems. Human umbilical cord mesenchymal stem cells (hUCMSCs) are an excellent seed cell choice for artificial livers because they change their characteristics to resemble hepatocyte-like cells (HLCs) following artificial liver transplantation. OBJECTIVE: This study aimed to determine whether the immunological characteristics of hUCMSCs are changed after being transformed into hepatocyte-like cells. METHODS: HUCMSCs were isolated by the adherent method. The following hUCMSC surface markers were detected using flow cytometry: CD45, CD90, CD105, CD34, and octamer-binding transcription factor 4 (OCT-4). Functional detection of adipogenic differentiation was performed. The hUCMSCs were cultured in complete medium (control group) or induction medium (induction group), and flow cytometry was used to detect cell surface markers. Peritoneal lavage fluid was collected after intraperitoneal injection of 1 × 106 cells/mouse over 40 minutes. The leukocyte count, labeled CD45, CD3, CD4 and CD8 antibodies, and flow detection of T lymphocyte subsets were determined using the peritoneal lavage fluid. RESULTS: Using phenotypic and functional identification, hUCMSCs were successfully isolated using a two-step induction method. The surface markers of the hUCMSCs cells changed after HLC induction. In vivo immune results showed that hUCMSCs and HLsC induced leukocyte production. CONCLUSION: Hepatic induction of hUCMSCs changes their cell surface markers. Both HLCs and hUCMSCs cause leukocytosis in vivo, but the immune response induced by HLCs is slightly stronger.

Molecular Level Modulation of Anthraquinone-containing Resorcinol-formaldehyde Resin Photocatalysts for H2 O2 Production with Exceeding 1.2 % Efficiency.

Designing polymeric photocatalysts at the molecular level to modulate the photogenerated charge behavior is a promising and challenging strategy for efficient hydrogen peroxide (H2 O2 ) photosynthesis. Here, we introduce electron-deficient 1,4-dihydroxyanthraquinone (DHAQ) into the framework of resorcinol-formaldehyde (RF) resin, which modulates the donor/acceptor ratio from the perspective of molecular design for promoting the charge separation. Interestingly, H2 O2 can be produced via oxygen reduction and water oxidation pathways, verified by isotopic labeling and in situ characterization techniques. Density functional theory (DFT) calculations elucidate that DHAQ can reduce the energy barrier for H2 O2 production. RF-DHAQ exhibits excellent overall photosynthesis of H2 O2 with a solar-to-chemical conversion (SCC) efficiency exceeding 1.2 %. This work opens a new avenue to design polymeric photocatalysts at the molecular level for high-efficiency artificial photosynthesis.

Mechanism of HBV-positive liver cancer cell exosomal miR-142-3p by inducing ferroptosis of M1 macrophages to promote liver cancer progression.

Background: Exosomes are becoming an important mediator of the interaction between tumor cells and the microenvironment. Ferroptosis is a newly discovered type of cell death. However, its role in the progression of liver cancer is largely unknown. The aim of the presents study was to analyze the mechanism by which hepatitis B virus (HBV)-positive liver cancer secretes exosomes to mediate the iron death of M1 macrophages, thereby promoting the development of liver cancer. Methods: Liver cancer tissues and peripheral blood with positive and negative clinical HBV infection were collected, and M-type macrophages, miR-142-3p, and recombinant solute carrier family 3, member 2 (SLC3A2) expressions were detected in the samples. CD80+ M1 macrophages and CD163+ M2 macrophages were isolated from the 2 tissues, and levels of miR-142-3p, SLC3A2, and ferroptosis markers were detected. Exosomes of HBV-positive hepatocellular carcinoma (HCC) cells were isolated and co-cultured with M1 macrophages to observe their effect on the invasion ability of HCC cells. Results: The expression of miR-142-3p significantly increased in the exosomes extracted from the peripheral blood of patients with HBV-positive liver cancer. Genes related to intracellular iron metabolism and homeostasis, such as ferritin heavy chain 1 (FTH1), transferrin receptor 1 (TfR1), recombinant glutathione peroxidase 4 (GPX4), and activating transcription factor 4 (ATF4), had abnormal expression levels in M1 macrophages. HBV-positive HCC exosomes treated with M1-type macrophages had a weakened inhibitory effect on the invasion of HCC cells, but ferroptosis inhibitors could reverse the effect of HBV-positive HCC exosomes treated M1-type macrophages on HCC cells. Knockdown of the expression of miR-142-3p can also weaken the invasive ability of liver cancer cells. Conclusions: The results of the present study confirmed that HBV-positive liver cancer cell exosomal miR-142-3p can promote the progression of liver cancer by inducing iron death of M1-type macrophages.

Exosomal miR-142-3p secreted by hepatitis B virus (HBV)-hepatocellular carcinoma (HCC) cells promotes ferroptosis of M1-type macrophages through SLC3A2 and the mechanism of HCC progression.

Background: Most patients with hepatitis B virus (HBV) infection will develop hepatocellular carcinoma (HCC). This study aimed to explore the potential mechanism of miR-142-3p in HCC caused by HBV infection. Methods: HepG2 cells and M1 macrophages were cocultured and then infected with HBV to establish an in vitro model. MicroRNA (miRNA) and messenger RNA (mRNA) expression was analyzed by quantitative reverse transcription polymerase chain reaction (RT-qPCR) and Western blot. The protein expressions of COX2, ACSL4, PTGS2, GPX4, and NOX1 were analyzed by Western blot. Flow cytometry and TUNEL assays were used to assess cell reactive oxygen species (ROS) and ferroptosis, respectively. Cell invasion and migration were measured by Transwell assay. To evaluate the ferroptosis of M1-type macrophages, glutathione (GSH), malondialdehyde (MDA), and Fe2+ content was detected by corresponding kits. Dual luciferase reporter gene detection verified the targeting relationship between miR-142-3p and SLC3A2. Results: MiR-142-3p was highly expressed in HBV-infected HCC patients and HBV-infected M1-type macrophages. Inhibition of miR-142-3p or overexpression of SLC3A2 reversed ferroptosis and inhibited the proliferation, migration, and invasion of HCC cells. Conclusions: Our findings indicated that miR-142-3p promoted HBV-infected M1-type macrophage ferroptosis through SLC3A2, affecting the production of GSH, MDA, and Fe2+ and accelerating the development of HCC. The regulation of miR-142-3p and its target genes will help to clarify the pathogenesis of HCC induced by HBV infection and provide new theoretical foundations and therapeutic targets.

Hydroxy-octadecenoic acids instead of phorbol esters are responsible for the Jatropha curcas kernel cake's toxicity.

The toxic kernel cake of Jatropha curcas (KCakeJ) is an emerging health and environmental concern. Although phorbol esters are widely recognized as the major toxin of KCakeJ, convincing evidence is absent. Here, we show that rather than phorbol esters an isomeric mixture of 11-hydroxy-9E-octadecenoic acid, 12-hydroxy-10E-octadecenoic acid and 12-hydroxy-10Z-octadecenoic acid (hydroxy-octadecenoic acids, molecular formula C18H34O3) is the major toxic component. The toxicities of hydroxy-octadecenoic acids on experimental animals, e.g. acute lethality, causing inflammation, pulmonary hemorrhage and thrombi, allergies, diarrhea and abortion, are consistent with those on human/animals caused by Jatropha seed and/or KCakeJ. The hydroxyl group and the double bond are essential for hydroxy-octadecenoic acids' toxicity. The main pathway of the toxicity mechanism includes down-regulating UCP3 gene expression, promoting ROS production, thus activating CD62P expression (platelet activation) and mast cell degranulation. The identification of the major toxin of KCakeJ lays a foundation for establishing an environmentally friendly Jatropha biofuel industry.

Bone marrow mesenchymal stem cells tune the differentiation of myeloid-derived suppressor cells in bleomycin-induced lung injury.

BACKGROUND: Bone marrow mesenchymal stem cells (BMSC) transfer has been attempted as a therapeutic strategy in experimental lung injury and fibrosis. Reduction of neutrophilic infiltration is one of the mechanisms involved in this effect. However, the mechanisms by which BMSC modulate neutrophil remains unknown. METHODS AND RESULTS: Exposure of mice to bleomycin (BLM) resulted in significant accumulation of cells that express neutrophilic markers Gr-1HighCD11b+Ly-6GHighF4/80-CD115-CD49d-. These cells lacked immunosuppressive activity and could not be defined as myeloid-derived suppressor cells (MDSC). When BMSC were administrated to BLM-treated mice, they tuned the differentiation of Gr-1HighCD11b+ toward Gr-1LowCD11b+ cells. Gr-1LowCD11b+ cells exhibited unsegmented nuclei and expressed F4/80, Ly-6C, CD49d, and CD115 markers. These cells had potent immunosuppressive activity and thus could be defined as monocytic MDSC. As a result of such immunoregulation, BMSC mediated a decrease of pro-inflammatory products and amelioration of lung injury in BLM-treated mice. Further study using antibody array showed increased expression of macrophage colony-stimulating factor (M-CSF) in BMSC-treated mice. Accumulation of Gr-1LowCD11b+ cells in BMSC-treated mice was abrogated in M-CSF neutralizing mice. The beneficial effect of BMSC was independent of the ability of the cells to engraft in lung and in vitro coculture study of BMSC with Gr-1+CD11b+ cells showed that the induction of Gr-1LowCD11b+ cells by BMSC was independent of cell-cell contact. CONCLUSIONS: These results document the generation of Gr-1HighCD11b+ cells in BLM-treated mice, and suggest that BMSC tune the differentiation of Gr-1HighCD11b+ toward Gr-1LowCD11b+ cells and therefore inhibit the progression of BLM-induced lung injury.

Research progress in liver tissue engineering.

Liver transplantation is the definitive treatment for patients with end-stage liver diseases (ESLD). However, it is hampered by shortage of liver donor. Liver tissue engineering, aiming at fabricating new livers in vitro, provides a potential resolution for donor shortage. Three elements need to be considered in liver tissue engineering: seeding cell resources, scaffolds and bioreactors. Studies have shown potential cell sources as hepatocytes, hepatic cell line, mesenchymal stem cells and others. They need scaffolds with perfect biocompatiblity, suitable micro-structure and appropriate degradation rate, which are essential charateristics for cell attachment, proliferation and secretion in forming extracellular matrix. The most promising scaffolds in research include decellularized whole liver, collagens and biocompatible plastic. The development and function of cells in scaffold need a microenvironment which can provide them with oxygen, nutrition, growth factors, et al. Bioreactor is expected to fulfill these requirements by mimicking the living condition in vivo. Although there is great progress in these three domains, a large gap stays still between their researches and applications. Herein, we summarized the recent development in these three major fields which are indispensable in liver tissue engineering.

The influence of myeloid-derived suppressor cells on angiogenesis and tumor growth after cancer surgery.

While myeloid-derived suppressor cells (MDSCs) have been reported to participate in the promotion of angiogenesis and tumor growth, little is known about their presence and function during perioperative period. Here, we demonstrated that human MDSCs expressing CD11b(+), CD33(+) and HLA-DR(-) significantly increased in lung cancer patients after thoracotomy. CD11b(+) CD33(+) HLA-DR(-) MDSCs isolated 24 hr after surgery from lung cancer patients were more efficient in promoting angiogenesis and tumor growth than MDSCs isolated before surgical operation in allograft tumor model. In addition, CD11b(+) CD33(+) HLA-DR(-) MDSCs produced high levels of MMP-9. Using an experimental lung metastasis mouse model, we demonstrated that the numbers of metastases on lung surface and Gr-1(+) CD11b(+) MDSCs at postoperative period were enhanced in proportion to the degree of surgical manipulation. We also examined that syngeneic bone marrow mesenchymal stem cells (BMSCs) significantly inhibited the induction and proliferation of Gr-1(+) CD11b(+) MDSCs and further prevented lung metastasis formation in the mice undergoing laparotomy. Taken together, our results suggest that postoperatively induced MDSCs were qualified with potent proangiogenic and tumor-promotive ability and this cell population should be considered as a target for preventing postoperative tumor metastasis.