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Influenza virus infection is one of the strongest pathogenic factors for the development of acute lung injury (ALI)/ acute respiratory distress syndrome (ARDS). However, the underlying cellular and molecular mechanisms have not been clarified. In this study, we aim to investigate whether melatonin modulates macrophage polarization, oxidative stress, and pyroptosis via activating Apolipoprotein E/low-density lipoprotein receptor (ApoE/LDLR) pathway in influenza A-induced ALI. Here, wild-type (WT) and ApoE-/- mice were instilled intratracheally with influenza A (H3N2) and injected intraperitoneally with melatonin for 7 consecutive days. In vitro, WT and ApoE-/- murine bone marrow-derived macrophages (BMDMs) were pretreated with melatonin before H3N2 stimulation. The results showed that melatonin administration significantly attenuated H3N2-induced pulmonary damage, leukocyte infiltration, and edema; decreased the expression of proinflammatory M1 markers; enhanced anti-inflammatory M2 markers; and switched the polarization of alveolar macrophages (AMs) from M1 to M2 phenotype. Additionally, melatonin inhibited reactive oxygen species- (ROS-) mediated pyroptosis shown by downregulation of malonaldehyde (MDA) and ROS levels as well as inhibition of the NLRP3/GSDMD pathway and lactate dehydrogenase (LDH) release. Strikingly, the ApoE/LDLR pathway was activated when melatonin was applied in H3N2-infected macrophages and mice. ApoE knockout mostly abrogated the protective impacts of melatonin on H3N2-induced ALI and its regulatory ability on macrophage polarization, oxidative stress, and pyroptosis. Furthermore, recombinant ApoE3 (re-ApoE3) inhibited H3N2-induced M1 polarization of BMDMs with upregulation of MT1 and MT2 expression, but re-ApoE2 and re-ApoE4 failed to do this. Melatonin combined with re-ApoE3 played more beneficial protective effects on modulating macrophage polarization, oxidative stress, and pyroptosis in H3N2-infected ApoE-/- BMDMs. Our study indicated that melatonin attenuated influenza A- (H3N2-) induced ALI by inhibiting the M1 polarization of pulmonary macrophages and ROS-mediated pyroptosis via activating the ApoE/LDLR pathway. This study suggested that melatonin-ApoE/LDLR axis may serve as a novel therapeutic strategy for influenza virus-induced ALI.

Acute lung injury (ALI)/ acute respiratory distress syndrome (ARDS) is featured by intensive inflammatory responses and oxidative stress, which lead to cytokine storms and pyroptosis. Here, we aimed to investigate whether melatonin was capable of alleviating LPS-induced ALI via activating the nuclear factor erythroid 2-related factor 2/heme oxygenase 1 (Nrf2/HO-1) signaling axis and inhibiting pyroptosis. Mice were injected with melatonin (30 mg/kg) intraperitoneally for consecutive five days before LPS instillation intratracheally, and human alveolar epithelial cell (AECⅡ) A549 cell lines and murine macrophages Raw264.7 cell lines were pretreated with melatonin (400 μM) before LPS (10 μg/ml) stimulation. The result demonstrated that LPS induced obvious lung injury characterized by alveolar damage, neutrophil infiltration and lung edema as well as the reduction of the survival rate of mice, which were totally reversed by melatonin pretreatment. Mechanistically, melatonin pretreatment activated nuclear factor erythroid2-related factor (Nrf) 2 signaling, subsequently, drove antioxidant pathways including significant increases in the expression of Nrf2, HO-1, NQO1, Mn-SOD and Catalase in vivo and in vitro. Simultaneously, melatonin inhibited ROS and MDA overproduction, iNOS expression as well as TNF-α and IL-1β expression and release. Furthermore, melatonin inhibited LPS-induced pyroptosis by reversing the overexpression of NLRP3, Caspase-1, IL-1β, IL-18 and GSDMD-N, as well as LDH release and TUNEL-positive cells in A549 cells and Raw264.7 cells. Overall, the current study suggests that melatonin exerts protective roles on LPS-induced ALI and pyroptosis by inhibiting NLRP3-GSDMD pathway via activating Nrf2/HO-1 signaling axis.

B-cell activating factor (BAFF) is critical for maintaining the development and homeostasis of B cells. Overexpression of BAFF is associated with autoimmune diseases and malignant B lymphoma. BAFF receptor (BAFF-R) was found to be a specific receptor of BAFF. It not only plays a significant role in splenic B-cell maturation but also works as a major mediator in BAFF-dependent costimulatory response in peripheral B and T cells. Previous studies have demonstrated that BAFF-R is related to several diseases; however, the molecular mechanism of BAFF-R genic transcription has not been clearly defined. The aim of this study was to investigate the transcriptional regulation of the BAFF-R gene. This study was designed to clone and characterize the 5'-regulatory region of the human BAFF-R gene and determine the mechanisms involved in its transcriptional regulation. In addition, the effects of interferon (IFN)-gamma and BAY11-7082 (inhibitor of nuclear factor [NF]-kappaB) on the expression and promoter activity of BAFF-R were examined. The results showed that the sequence between -1420 and +261 could be a core promoter region, and -1562 and -1420 bp harbored a transcriptive silencer. IFN-gamma promoted BAFF-R promoter activity and upregulated BAFF-R mRNA expression. BAY11-7082 (inhibitor of NF-kappaB) exhibited an inhibitory effect on BAFF-R promoter activity and downregulated BAFF-R mRNA expression. Our data provided novel evidence to clarify the mechanism of transcriptional regulation of BAFF-R and illustrated that IFN-gamma and NF-kappaB pathway were involved in regulating BAFF-R expression. Thus some BAFF-R-related diseases might be cured by blocking transcriptional regulation of BAFF-R and reducing its expression.

To investigate the effects of a proliferation-inducing ligand (APRlL) on colorectal cancer (CRC) cell growth and migration, and to observe the role of APRIL in CRC biological behavior.The siRNA plasmid vector targeting APRIL gene (APRIL-siRNA) was transfected into human colorectal cancer SW480 cells and recombinant human APRIL (rhAPRIL) was used to stimulate human colorectal cancer HCT-116 cells. Cell proliferation activity was analyzed using cell counting kit-8 (CCK-8), cell cycle was detected by flow cytometry, and the protein expression of cyclin D1, p21 and Bcl-2 was detected by Western blot analysis. Tumor cell migration and invasion were measured by Transwell chambers. RT-PCR was applied to examine the mRNA expression level of MMP-2 and MMP-9. APRIL-siRNA was used to transfect directly SW480 cells, which were injected subcutaneously into nude mice, then the tumor growth and metastasis were observed.Cell proliferation ability of APRIL-siRNA-transfected SW480 cells was drastically repressed, and the percentage of G0/G1 phase cells was significantly increased (t = 4.12, P0.05), accompanied with depressed cyclin D1, Bcl-2 expression and elevated p21 expression. Cell proliferation ability of rhAPRIL-stimulated HCT-116 cells was promoted with a decreased G0/G1 phase ratio (t = 3.31, P0.05). cyclin D1 and Bcl-2 protein expression was up-regulated while p21 was down-regulated by rhAPRIL stimulation. Metastatic and invasive capacities of APRIL-siRNA-transfected SW480 cells were significantly inhibited compared with their respective controls (both P0.05), accompanied with the deregulated MMP-2 and MMP-9 mRNA expression. Metastatic and invasive capacities of rhAPRIL-stimulated HCT-116 cells were promoted with up-regulated MMP-2 and MMP-9 mRNA expression(both P0.05). Tumor growth in the group transfected with APRIL-siRNA appeared to be slower than that in the control groups and the expression of MMP-2, MMP-9 in tumor tissues was depressed in the APRIL-siRNA group.APRIL facilitates tumor growth and metastasis, and is associated with carcinogenesis and prognosis. Our findings suggest that APRIL might be used as a novel target for the intervention and therapy of colorectal cancer.

To investigate the expression of B lymphocyte stimulator (BlyS) and its receptors in multiple myeloma (MM) cells, and to explore the relationship between BLyS and the development of human multiple myeloma.Flow cytometry, RT-PCR and Western blot were used to examine the expression of BLyS and its receptors in MM (KM3 and CZ1) cells. Fluorescence immunocytochemical method and confocal laser scanning technique were applied to the localization of BLyS in KM3 cell. WST proliferation assay was used to examine the effect of BLyS on MM cells growth and survival. Linear correlation analysis was used to detect LDH and beta 2-microglobulin (beta2M) levels with BLyS protein and mRNA expressions in MM patients.(1) BLyS and its receptors were expressed in MM cells. (2) BLyS protein was localized on the KM3 plasma membrane. (3) BLyS promoted survival and proliferation of MM cells. (4) MM patients had significantly higher expression levels of BLyS [77.42% (24/31)] BLyS mRNA [93.55% (29/31)], which were significantly correlated with the levels of LDH and beta 2-microglobulin (beta2M).BLyS and its receptors in MM cell lines and MM patient bone marrow might have a potential role in the growth and survival of malignant plasma cells.

To construct the eukaryotic expression vector for early human B-cell factor 3(EBF3) fused with the enhanced green fluorescent protein (EGFP) and express the fusion protein EBF3-EGFP in HepG2 cells.The intact EBF3 gene was amplified from RNA isolated from the placental tissue by RT-PCR. Then it was inserted into the pEGFP-N1 vector to construct the recombinant eukaryotic expression vector pEGFP/EBF3. The fusion protein EBF3-EGFP was expressed in HepG2 cells by the transfection of pEGFP/EBF3 into the cells.The pEGFP/EBF3 recombinant expression vector was constructed and confirmed by DNA sequencing, enzymatic digestion and PCR identification. 24 h after the fusion protein EBF3-EGFP was transfected wiht pEGFP/EBF3, it was observed mainly in the cellular nucleus under the inverted fluorescence microscope. Both pEGFP/EBF3 and pEGFP-N1 were transfected into human HepG2 cells. 24 h after the transfection, the proportion of transfection was about 52% and 59%, respectively. Western blot analysis confirmed that the EBF3-EGFP fusion proteins of M(r) 87 000 were detected in the cytoplasmic and nuclear protein of HepG2 transfected with pEGFP/EBF3 for 24 h or 48 h. The cell proportion in S phase increased in HepG2 cells transfected with pEGFP/EBF3 in comparison with HepG2 cells transfected with pEGFP-N1 or untransfected. These findings suggested that the transfection of EBF3 gene into HepG2 induced the cell proliferation from G1 phase to G2 phase by increasing the number of cells.The construction of pEGFP/EBF3 eukaryotic expression vector and the expression of EBF3-EGFP fusion protein in HepG2 cells lay a foundation for further study of the relationship between EBF3 and its growth and the proliferation of tumor cells.

To investigate the gene mutation in the areas of pre core/core (Pre C/C) and basic core promotor (BCP) of HBV DNA and its clinical significance.The nt 1 735-1 965 segment of HBV DNA was amplified with PCR in 54 cases with chronic hepatitis B and 10 cases with post-hepatitis cirrhosis. Then the PCR product was sequenced.There were 168 site mutations in 48.5% (33/68) cases with hepatitis B. The first ten mutation sites were nt 1 764 (58.8%), 1 762 (48.5%), 1 799 (21.0%), 1 766 (14.7%), 1 896 (13.2%), 1 754 (8.8%), 1 899 (8.8%), 1 768 (7.4%), 1 814 (7.4%) and 1 913 (7.4%). Three rare mutations of nt 1907, 1 922 and 1 923 were also detected. The mutations of nt 1 896, 1 764 and 1 762 were found in 16.7%, 35.2% and 35.2% of chronic hepatitis, and in 30.0%, 60.0% and 60.0% respectively of post-hepatitis cirrhosis cases. There was statistical significance between the two groups (P0.01).The mutations in the areas of Pre C/C and BCP of HBV DNA might possibly be associated with liver fibrosis. There are many mutation sites in HBV DNA and mutation occurs frequently, therefore gene sequencing is helpful to the design of gene chip and to clinical application.