hMSCs-derived exosome circCDK13 inhibits liver fibrosis by regulating the expression of MFGE8 through miR-17-5p/KAT2B.

OBJECTIVE: To investigate the effects of human bone marrow mesenchymal stem cells (hMSCs)-derived exosome circCDK13 on liver fibrosis and its mechanism. METHODS: Exosomes derived from hMSCs were extracted and identified by flow cytometry and osteogenic and adipogenic induction, and the expressions of marker proteins on the surface of exosomes were detected by western blot. Cell proliferation was measured by CCK8 assay, the expression of active markers of HSCs by immunofluorescence, and the expressions of fibrosis-related factors by western blot. A mouse model of liver fibrosis was established by intraperitoneal injection of thioacetamide (TAA). Fibrosis was detected by HE staining, Masson staining, and Sirius red staining. Western blot was utilized to test the expressions of PI3K/AKT and NF-κB pathway related proteins, dual-luciferase reporter assay and RIP assay to validate the binding between circCDK13 and miR-17-5p as well as between miR-17-5p and KAT2B, and ChIP to validate the effect of KAT2B on H3 acetylation and MFGE8 transcription. RESULTS: hMSCs-derived exosomes inhibited liver fibrosis mainly through circCDK13. Dual-luciferase reporter assay and RIP assay demonstrated the binding between circCDK13 and miR-17-5p as well as between miR-17-5p and KAT2B. Further experimental results indicated that circCDK13 mediated liver fibrosis by regulating the miR-17-5p/KAT2B axis, and KAT2B promoted MFGE8 transcription by H3 acetylation. Exo-circCDK13 inhibited PI3K/AKT and NF-κB signaling pathways activation through regulating the miR-17-5p/KAT2B axis. CONCLUSION: hMSCs-derived exosome circCDK13 inhibited liver fibrosis by regulating the expression of MFGE8 through miR-17-5p/KAT2B axis.

Mn-SOD alleviates methotrexate-related hepatocellular injury via GSK-3ß affecting anti-oxidative stress of HO-1 and Drp1. / Mn-SOD通过GSK-3ß影响HO-1和Drp1的抗氧化应激减轻MTXç›¸å ³è‚ç»†èƒžæŸä¼¤.

OBJECTIVES: Methotrexate (MTX) is the most common therapeutic agent that may have the risk of drug-induced liver injury. Its pathogenic mechanism is related to oxidative stress caused by mitochondrial dysfunction. Superoxide dismutase (SOD), including manganese-containing SOD (Mn-SOD), can exert its effect of anti-oxidative stress by scavenging superoxide free radicals. Accordingly, this study is performed to explore the underlying molecular mechanism via observing whether Mn-SOD could affect the damage of MTX to hepatocytes. METHODS: Human hepatocyte cell line L-02 was cultured in vitro and divided into 4 groups, including a blank group with the addition of the same volume of serum-free medium, a MTX group (40 µg/well MTX drug-treatment), a MTX+NC group (40 µg/well MTX drug-treatment+blank plasmid), and a MTX+SOD group (40 µg/well MTX drug-treatment+Mn-SOD plasmid). The levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and microRNA-122 (miR-122) in the supernatant of cell culture were respectively detected by automatic biochemical analytical instrument and real-time RT-PCR to evaluate the degree of hepatocyte damage in each group. MitoSOX fluorescent probe was used to label intracellular superoxide in each group, and cell apoptosis was detected by flow cytometry. Meanwhile, the contents of glycogen synthase kinase-3 beta (GSK-3ß), hemeoxygenase-1 (HO-1), mitochondrial fission-mediated protein of dynamin-related protein 1 (Drp1), and Mn-SOD were detected by Western blotting. RESULTS: Compared with the blank group, the levels of ALT, AST, and miR-122 in the supernatant of hepatocyte culture of the MTX group and MTX+NC group were significantly elevated (all P <0.05), and that in the MTX+SOD group were significantly decreased ( P <0.05) and equivalent to that in the blank group. MitoSOX staining revealed that the MTX group and MTX+NC had the most abundant superoxide; and the amount was significantly reduced in the MTX+SOD group, without a significant difference when compared with the blank group. Furthermore, the results of flow cytometry indicated that compared with the blank group, the MTX group and MTX+NC group showed significantly increased cell apoptosis ( P <0.05); while there was obviously reduced cell apoptosis in the MTX+SOD group than that in the MTX group and MTX+NC group ( P <0.05). According to the results of Western blotting, the blank group and MTX+SOD group had higher expressions of Mn-SOD, p-GSK-3ß, and HO-1; while the MTX group and MTX+NC group exhibited remarkably lower levels of Mn-SOD, p-GSK-3ß, and HO-1 than those in the blank group ( P <0.05). Besides, a completely opposite trend was found in the expression of Drp1, which was highly expressed in the MTX group and MTX+NC group, but lowly expressed in the blank group and the MTX+SOD group. CONCLUSIONS: MTX may induce hepatocyte damage, and one of the mechanisms may be due to the decrease of intracellular Mn-SOD level, which can cause the accumulation of superoxide, affect the levels of HO-1 and Drp1 through GSK-3ß leading to mitochondrial damage and cell apoptosis. High expression of Mn-SOD intracellularly through exogenous introduction can scavenge drug-produced superoxide, affect HO-1 and Drp1 levels through GSK-3ß, activate mitochondria, protect cells against damage from oxidative stress, and inhibit hepatocyte apoptosis eventually. So exogenous introduction of SOD may be a potential therapeutic approach to block or reverse MTX-related hepatocyte injury.

Igf2bp2 knockdown improves CCl4-induced liver fibrosis and TGF-ß-activated mouse hepatic stellate cells by regulating Tgfbr1.

Progressive liver fibrosis is a dynamic process characterized by the net accumulation of extracellular matrix (ECM), which could eventually develop into cirrhosis, leading to malignant transformation. In this study, insulin-like growth factor 2 mRNA binding protein 2 (Igf2bp2) was found to be up-regulated in carbon tetrachloride (CCl4)-induced liver fibrosis and transforming growth factor-beta 1 (TGF-ß)-activated hepatic stellate cells (HSCs). Igf2bp2 knockdown in the CCl4-induced hepatic fibrosis mice model significantly improved CCl4-induced liver damage by decreasing necrosis and fibrotic septa, reducing hydroxyproline levels, and down-regulating fibrotic markers levels. In TGF-ß-activated HSCs, Igf2bp2 knockdown partially attenuated TGF-ß-induced cellular effects by suppressing HSCs viability and DNA synthesis and reducing the ECM-associated factors such as α-SMA, COLLAGEN I, and COLLAGEN III. Integrative network and signaling analysis revealed that the Igf2bp2 could bind to Tgfbr1. Transforming growth factor-beta receptor 1 (Tgfbr1) was found to be significantly up-regulated in the fibrotic liver and activated HSCs, and positively correlated with Igf2bp2. Tgfbr1 knockdown partially eliminated TGF-ß-induced fibrotic changes and Igf2bp2 overexpression effects on TGF-ß-activated HSCs in vitro. Moreover, Igf2bp2 overexpression promoted the phosphorylation of SMAD2/SMAD3, AKT, and PI3K, whereas Tgfbr1 knockdown exhibited the opposite effect; Tgfbr1 knockdown also partially attenuated the effects of Igf2bp2 overexpression on the phosphorylation of SMAD2/SMAD3, AKT, and PI3K. In closing, Igf2bp2 and Tgfbr1 are up-regulated in CCl4-induced liver fibrosis and TGF-ß-activated mHSCs. Igf2bp2 knockdown improved CCl4-induced liver fibrosis and TGF-ß-activated HSCs by targeting Tgfbr1, possibly through the PI3K/Akt pathway.

A Special Case of Cirrhosis with a Novel ATP7B Mutation and Occult Chronic HBV Infection.

Wilson's disease (WD) is an autosomal recessive disorder that affects copper metabolism. Mutations of the ATP7B gene have been found to be strongly associated with a risk of developing WD; and at present, more than 500 mutations have been reported in WD patients. The Arg778Leu and Arg952Lys mutations in exons 8 and 12, respectively, are highly prevalent in the Chinese population. However, early detection of WD is difficult due to the extreme variations in mutations of ATP7B, and the lack of specific clinical symptoms during the early stages of the disease. Meanwhile, the early stage of occult hepatitis B infection lacks typical clinical manifestations, which easily leads to it being misdiagnosed as liver cirrhosis. We report a new pathogenic exon 19 mutation of ATP7B，which can potentially contribute to the early genetic diagnosis and prompt treatment of WD. Key Words: Wilson's disease, Gene mutation, ATP7B, Cirrhosis, Occult hepatitis B infection.

HBV down-regulates PTEN expression via Nrf2/GSK3ß signaling pathway. / HBV通过Nrf2/GSK3ß信号通路下调PTEN的表达.

OBJECTIVES: To investigate the effect of HBV infection on PTEN expression, and to explore the possible molecular mechanisms. METHODS: HepG2 cells and HepG2.2.15 cells were cultured under suitable conditions for 48 hours, and the expressions of PTEN, Nrf2 and pGSK3ß in HepG2 and HepG2.2.15 cells were detected by Western blotting. After the blank plasmid (EV) and the plasmid pWXL-Nrf2 were transiently transfected into HepG2 and HepG2.2.15 cells, respectively, the HepG2 and HepG2.2.15 cells were treated with the selective inhibitor of GSK3ß (25 nmol/L LiCl). After 48 h, the expressions of Nrf2, pGSK3ß and PTEN in HepG2 and HepG2.2.15 cells were examined by Western blotting. RESULTS: Expression of PTEN was reduced and the levels of Nrf2 and pGSK3ß were increased in HepG2.2.15 cells compared with those in the HepG2 cells (all P<0.05). After transfection with pWXL-Nrf2, the protein expression of Nrf2 and pGSK3ß in cells were significantly increased while the protein expression of PTEN was decreased (all P<0.05). Furthermore, LiCl treatment up-regulated the protein expression of Nrf2 and pGSK3ß, and eventually suppressed the production of PTEN (all P<0.05). CONCLUSIONS: HBV may down-regulate PTEN expression via Nrf2/GSK3ß signaling pathway, which may provide new ideas for the targeting therapy of hepatocellular carcinoma.

Novel Bioactive Penicipyrroether A and Pyrrospirone J from the Marine-Derived Penicillium sp. ZZ380.

The marine-sourced fungus Penicillium sp. ZZ380 was previously reported to have the ability to produce a series of new pyrrospirone alkaloids. Further investigation on this strain resulted in the isolation and identification of novel penicipyrroether A and pyrrospirone J. Each of them represents the first example of its structural type, with a unique 6/5/6/5 polycyclic fusion that is different from the 6/5/6/6 fused ring system for the reported pyrrospirones. Their structures were elucidated by extensive nuclear magnetic resonance (NMR) and high resolution electrospray ionization mass spectroscopy (HRESIMS) spectroscopic analyses, electronic circular dichroism (ECD) and 13C NMR calculations and X-ray single crystal diffraction. Penicipyrroether A showed potent antiproliferative activity against human glioma U87MG and U251 cells with half maximal inhibitory concentration (IC50) values of 1.64-5.50 µM and antibacterial inhibitory activity with minimum inhibitory concentration (MIC) values of 1.7 µg/mL against methicillin-resistant Staphylococcus aureus and 3.0 µg/mL against Escherichia coli.

Bioactive Penicipyrrodiether A, an Adduct of GKK1032 Analogue and Phenol A Derivative, from a Marine-Sourced Fungus Penicillium sp. ZZ380.

Penicipyrrodiether A, an adduct of GKK1032 analogue and phenol A derivative, was isolated from a culture of marine-associated fungus Penicillium sp. ZZ380 and represents the first example of this type of fungal metabolite. Its structure was elucidated by extensive spectroscopic analyses, including 1D- and 2D-NMR, HRESIMS, MS/MS, and electronic circular dichroism calculation as well as single-crystal X-ray diffraction. Penicipyrrodiether A showed antibacterial activity in inhibiting the growth of methicillin-resistant Staphylococcus aureus with a MIC value of 5.0 µg/mL. Its plausible pathway for biosynthesis has been proposed.

Anti-glioma Natural Products Downregulating Tumor Glycolytic Enzymes from Marine Actinomycete Streptomyces sp. ZZ406.

Marine natural products are important resources for discovering novel anticancer drugs. In this study, an extract prepared from the culture of a sea anemone-derived actinomycete Streptomyces sp. ZZ406 in soluble starch and casein-related liquid medium was found to have activity in inhibiting the proliferation of glioma cells and reducing the production of lactate in glioma cells. Chemical investigation of this active crude extract resulted in the isolation of four new compounds and seven known ones. Structures of the new compounds were determined by a combination of extensive NMR analyses, HRESIMS and MS-MS data, electronic circular dichroism calculation, chemical degradation, and Marfey's method. New compound 1 showed potent activity against the proliferation of different glioma cells with IC50 values of 4.7 to 8.1 µM, high selectivity index (>12.3 to 21.3), and good stability in human liver microsomes. Western blot analysis revealed that compound 1 remarkably downregulated the expressions of several important glioma glycolytic enzymes. The data from this study suggested that compound 1 might have potential as a novel anti-glioma agent to be further investigated.

Antiproliferative cyclodepsipeptides from the marine actinomycete Streptomyces sp. P11-23B downregulating the tumor metabolic enzymes of glycolysis, glutaminolysis, and lipogenesis.

Two cyclodepsipeptides and a known cyclodepsipeptide valinomycin were isolated from a culture of the marine actinomycete Streptomyces sp. P11-23B. Their structures were established based on NMR, HRESIMS, and MS-MS spectroscopic interpretation as well as by chemical degradation. Both streptodepsipeptides P11A and P11B inhibited proliferation of different glioma cell lines, with IC50 values ranging from 0.1 µM to 1.4 µM. Streptodepsipeptide P11A was found to block the cell cycle at the G0/G1 phase and induce apoptosis in glioma cells. Further investigation demonstrated that streptodepsipeptide P11A downregulated expression of HK2, PFKFB3, PKM2, GLS, and FASN, important tumor metabolic enzymes. Data from this study suggested that targeting multiple tumor metabolic regulators might be one anti-glioma mechanism of streptodepsipeptide P11A. A possible mechanism for this class of streptodepsipeptides is reported herein.