NDH-1 Is Important for Photosystem I Function of Synechocystis sp. Strain PCC 6803 under Environmental Stress Conditions

Cyanobacterial NDH-1 interacts with photosystem I (PSI) to form an NDH-1-PSI supercomplex. Here, we observed that absence of NDH-1 had little, if any, effect on the functional fractions of PSI under growth conditions, but significantly reduced the functional fractions of PSI when cells of Synechocystis sp. strain PCC 6803 were moved to conditions of multiple stresses. The significant reduction in NDH-1-dependent functional fraction of PSI was initiated after PSII activity was impaired. This finding is consistent with our observation that the functional fraction of PSI under growth conditions was rapidly and significantly decreased with increasing concentrations of DCMU, which rapidly and significantly suppressed PSII activity by blocking the transfer of electrons from QA to QB in the PSII reaction center. Furthermore, absence of NDH-1 resulted in the PSI limitation at the functionality of PSI itself but not its donor-side and acceptor-side under conditions of multiple stresses. This was supported by the result of a significant destabilization of the PSI complex in the absence of NDH-1 but the presence of multiple stresses. Based on the above results, we propose that NDH-1 is important for PSI function of Synechocystis sp. strain PCC 6803 mainly via maintaining stabilization of PSI under conditions of environmental stresses.This work was supported by the National Natural Science Foundation of China (grant nos. 31370270, 31570235, 31770259, and 31700205), China Postdoctoral Science Foundation (grant nos. 2015M581643 and 2017T100304), Shanghai Science and Technology Committee (grant no. 17070502900) and Project of Shanghai Normal University (grant no. SK201705)

Hemojuvelin-Neogenin Interaction Is Required for Bone Morphogenic Protein-4-induced Hepcidin Expression

Hemojuvelin (HJV) is a glycosylphosphatidylinositol-linked protein and binds both bone morphogenic proteins (BMPs) and neogenin. Cellular HJV acts as a BMP co-receptor to enhance the transcription of hepcidin, a key iron regulatory hormone secreted predominantly by liver hepatocytes. In this study we characterized the role of neogenin in HJV-regulated hepcidin expression. Both HJV and neogenin were expressed in liver hepatocytes. Knockdown of neogenin decreased BMP4-induced hepcidin mRNA levels by 16-fold in HJV-expressing HepG2 cells but only by about 2-fold in cells transfected with either empty vector or G99V mutant HJV that does not bind BMPs. Further studies indicated that disruption of the HJV-neogenin interaction is responsible for a marked suppression of hepcidin expression. Moreover, in vivo studies showed that hepatic hepcidin mRNA could be significantly suppressed by blocking the interaction of HJV with full-length neogenin with a soluble fragment of neogenin in mice. Together, these results suggest that the HJV-neogenin interaction is required for the BMP-mediated induction of hepcidin expression when HJV is expressed. Combined with our previous studies, our results support that hepatic neogenin possesses two functions, mediation of cellular HJV release, and stimulation of HJV-enhanced hepcidin expression

The relationship between sleep quality and daytime dysfunction among college students in China during COVID-19: a cross-sectional study

ObjectiveCollege Students’ sleep quality and daytime dysfunction have become worse since the COVID-19 outbreak, the purpose of this study was to explore the relationship between sleep quality and daytime dysfunction among college students during the COVID-19 (Corona Virus Disease 2019) period.MethodsThis research adopts the form of cluster random sampling of online questionnaires. From April 5 to 16 in 2022, questionnaires are distributed to college students in various universities in Fujian Province, China and the general information questionnaire and PSQI scale are used for investigation. SPSS26.0 was used to conduct an independent sample t-test and variance analysis on the data, multi-factorial analysis was performed using logistic regression analysis. The main outcome variables are the score of subjective sleep quality and daytime dysfunction.ResultsDuring the COVID-19 period, the average PSQI score of the tested college students was 6.17 ± 3.263, and the sleep disorder rate was 29.6%, the daytime dysfunction rate was 85%. Being female, study liberal art/science/ engineering, irritable (due to limited outdoor), prolong electronic entertainment time were associated with low sleep quality (p < 0.001), and the occurrence of daytime dysfunction was higher than other groups (p < 0.001). Logistics regression analysis showed that sleep quality and daytime dysfunction were associated with gender, profession, irritable (due to limited outdoor), and prolonged electronic entertainment time (p < 0.001).ConclusionDuring the COVID-19 epidemic, the sleep quality of college students was affected, and different degrees of daytime dysfunction have appeared, both are in worse condition than before the COVID-19 outbreak. Sleep quality may was inversely associated with daytime dysfunction

NDH-1 Is Important for Photosystem I Function of Synechocystis sp. Strain PCC 6803 under Environmental Stress Conditions

Cyanobacterial NDH-1 interacts with photosystem I (PSI) to form an NDH-1-PSI supercomplex. Here, we observed that absence of NDH-1 had little, if any, effect on the functional fractions of PSI under growth conditions, but significantly reduced the functional fractions of PSI when cells of Synechocystis sp. strain PCC 6803 were moved to conditions of multiple stresses. The significant reduction in NDH-1-dependent functional fraction of PSI was initiated after PSII activity was impaired. This finding is consistent with our observation that the functional fraction of PSI under growth conditions was rapidly and significantly decreased with increasing concentrations of DCMU, which rapidly and significantly suppressed PSII activity by blocking the transfer of electrons from QA to QB in the PSII reaction center. Furthermore, absence of NDH-1 resulted in the PSI limitation at the functionality of PSI itself but not its donor-side and acceptor-side under conditions of multiple stresses. This was supported by the result of a significant destabilization of the PSI complex in the absence of NDH-1 but the presence of multiple stresses. Based on the above results, we propose that NDH-1 is important for PSI function of Synechocystis sp. strain PCC 6803 mainly via maintaining stabilization of PSI under conditions of environmental stresses

Widely targeted metabolomic analysis reveals that volatile metabolites in cigar tobacco leaves dynamically change during fermentation

Changes in volatile metabolites during cigar tobacco leaves fermentation as well as the metabolic pathways of metabolites with significant differences were investigated to determine the influence of cigar tobacco leaves fermentation on its flavor. The volatile substances in cigar tobacco leaves at different stages were detected by headspace-solid phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS), and the main differences in volatile substances in cigar tobacco leaves at different fermentation stages of Yunxue1 in Yuxi production area were analyzed by principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA). The results show that in the process of cigar tobacco leaves fermentation (YXF0, YXF1, YXF2, YXF3, YXF4, YXF5), a total of 613 volatile metabolites were detected, and a significant difference was found in 263 kinds of metabolites. Among them, the main upregulated differential metabolites were 1,3,6,10-Cyclotetradecatetraene, 3,7,11-trimethyl-14-(1-methylethyl)-, [S-(E,Z,E,E)]-, Benzoic acid, Benzaldehyde, etc. While the main downregulated differential metabolites included beta.-Myrcene, trans-Farnesol, etc. The metabolites with significant differences are mainly concentrated in the biosynthesis of monoterpenes, diterpenes, sesquiterpenes and triterpenes, the degradation metabolism of amino acids, such as valine, leucine and isoleucine, and the biosynthesis of phenylpropyl. There were 8 different metabolites in 5 groups, including 4- (1-methylethyl) -1-cyclohexene-1-formaldehyde、2, 4-dihydroxyacetophenone、2-methylbutyl 3-methylbutyrate and methylpyrazine, all of which showed upregulation trend during fermentation. In the fermentation process, volatile metabolites participate in various synthesis and degradation pathways. The biosynthesis pathway of terpenes and amino acid synthesis and degradation pathway are connected to produce various terpenes, aldehydes and other substances, such as 1,3,6,10-Cyclotetradecatetraene, 3,7,11-trimethyl-14-(1-methylethyl)-, [S-(E,Z,E,E)]-、benzaldehyde and 4-hydroxybenzaldehyde, which are conducive to the overall flavor and quality of cigar tobacco leaves

The mitochondrial chaperone Prohibitin 1 negatively regulates interleukin-8 in human liver cancers.

Prohibitin 1 (PHB1) is a mitochondrial chaperone whose expression is dysregulated in cancer. In liver cancer, PHB1 acts as a tumor suppressor, but the mechanisms of tumor suppression are incompletely understood. Here we aimed to determine PHB1 target genes to better understand how PHB1 influences liver tumorigenesis. Using RNA-Seq analysis, we found interleukin-8 (IL-8) to be one of the most highly up-regulated genes following PHB1 silencing in HepG2 cells. Induction of IL-8 expression also occurred in multiple liver and nonliver cancer cell lines. We examined samples from 178 patients with hepatocellular carcinoma (HCC) and found that IL-8 mRNA levels were increased, whereas PHB1 mRNA levels were decreased, in the tumors compared with adjacent nontumorous tissues. Notably, HCC patients with high IL-8 expression have significantly reduced survival. An inverse correlation between PHB1 and IL-8 mRNA levels is found in HCCs with reduced PHB1 expression. To understand the molecular basis for these observations, we altered PHB1 levels in liver cancer cells. Overexpression of PHB1 resulted in lowered IL-8 expression and secretion. Silencing PHB1 increased c-Jun N-terminal kinase (JNK) and NF-κB activity, induced nuclear accumulation of c-JUN and p65, and enhanced their binding to the IL-8 promoter containing AP-1 and NF-κB elements. Conditioned medium from PHB1-silenced HepG2 cells increased migration and invasion of parental HepG2 and SK-hep-1 cells, and this was blocked by co-treatment with neutralizing IL-8 antibody. In summary, our findings show that reduced PHB1 expression induces IL-8 transcription by activating NF-κB and AP-1, resulting in enhanced IL-8 expression and release to promote tumorigenesis

CSNK2A1-mediated MAX phosphorylation upregulates HMGB1 and IL-6 expression in cholangiocarcinoma progression.

BackgroundWe established a novel diethylnitrosamine (DEN) -induced mouse model that reflected the progression of cholangiocarcinoma (CCA) from atypical cystic hyperplasia.MethodsBALB/c mice were administered DEN by oral gavage. Cells isolated from livers were analyzed for expression of CSNK2A1, MAX and MAX-interacting proteins. Human CCA cell lines (MzChA-1, HuCCT1), normal human cholangiocyte (H69), human hepatic stellate cells (LX-2), macrophages (RAW 264.7), and primary hepatic cells were used for cellular and molecular biology assays.ResultsExpression of MAX, CSNK2A1, C-MYC, β-catenin, HMGB1, and IL-6 was upregulated in hepatic cells from CCA liver tissue. The half-life of MAX is higher in CCA cells, and this favors their proliferation. Overexpression of MAX increased growth, migration, and invasion of MzChA-1, whereas silencing of MAX had the opposite effect. MAX positively regulated IL-6 and HMGB1 through paracrine signaling in HepG2, LX2, and RAW cells and autocrine signaling in MzChA-1 cells. CSNK2A1-mediated MAX phosphorylation shifts MAX-MAX homodimer to C-MYC-MAX and β-catenin-MAX heterodimers and increases the HMGB1 and IL-6 promoter activities. Increase of MAX phosphorylation promotes cell proliferation, migration, invasion, and cholangiocarcinogenesis. The casein kinase 2 inhibitor CX-4945 induces cell cycle arrest and inhibits cell proliferation, migration, invasion, and carcinogenesis in MzChA-1 cells through the downregulation of CSNK2A1, MAX, and MAX-interaction proteins.ConclusionC-MYC-MAX and β-catenin-MAX binding to E-box site or β-catenin-MAX bound to TCFs/LEF1 enhanced HMGB1 or IL-6 promoter activities, respectively. IL-6 and HMGB1 secreted by hepatocytes, HSCs, and KCs exert paracrine effects on cholangiocytes to promote cell growth, migration, and invasion and lead to the progression of cholangiocarcinogenesis. CX-4945 provides perspectives on therapeutic strategies to attenuate progression from atypical cystic hyperplasia to cholangiocarcinogenesis

Deregulated 14-3-3ζ and methionine adenosyltransferase α1 interplay promotes liver cancer tumorigenesis in mice and humans.

Methionine adenosyltransferase 1A (MAT1A) is a tumor suppressor downregulated in hepatocellular carcinoma and cholangiocarcinoma, two of the fastest rising cancers worldwide. We compared MATα1 (protein encoded by MAT1A) interactome in normal versus cancerous livers by mass spectrometry to reveal interactions with 14-3-3ζ. The MATα1/14-3-3ζ complex was critical for the expression of 14-3-3ζ. Similarly, the knockdown and small molecule inhibitor for 14-3-3ζ (BV02), and ChIP analysis demonstrated the role of 14-3-3ζ in suppressing MAT1A expression. Interaction between MATα1 and 14-3-3ζ occurs directly and is enhanced by AKT2 phosphorylation of MATα1. Blocking their interaction enabled nuclear MATα1 translocation and inhibited tumorigenesis. In contrast, overexpressing 14-3-3ζ lowered nuclear MATα1 levels and promoted tumor progression. However, tumor-promoting effects of 14-3-3ζ were eliminated when liver cancer cells expressed mutant MATα1 unable to interact with 14-3-3ζ. Taken together, the reciprocal negative regulation that MATα1 and 14-3-3ζ exert is a key mechanism in liver tumorigenesis

Mechanisms of MAFG Dysregulation in Cholestatic Liver Injury and Development of Liver Cancer.

BACKGROUND & AIMS:MAF bZIP transcription factor G (MAFG) is activated by the farnesoid X receptor to repress bile acid synthesis. However, expression of MAFG increases during cholestatic liver injury in mice and in cholangiocarcinomas. MAFG interacts directly with methionine adenosyltransferase α1 (MATα1) and other transcription factors at the E-box element to repress transcription. We studied mechanisms of MAFG up-regulation in cholestatic tissues and the pathways by which S-adenosylmethionine (SAMe) and ursodeoxycholic acid (UDCA) prevent the increase in MAFG expression. We also investigated whether obeticholic acid (OCA), an farnesoid X receptor agonist, affects MAFG expression and how it contributes to tumor growth in mice. METHODS:We obtained 7 human cholangiocarcinoma specimens and adjacent non-tumor tissues from patients that underwent surgical resection in California and 113 hepatocellular carcinoma (HCC) specimens and adjacent non-tumor tissues from China, along with clinical data from patients. Tissues were analyzed by immunohistochemistry. MAT1A, MAT2A, c-MYC, and MAFG were overexpressed or knocked down with small interfering RNAs in MzChA-1, KMCH, Hep3B, and HepG2 cells; some cells were incubated with lithocholic acid (LCA, which causes the same changes in gene expression observed during chronic cholestatic liver injury in mice), SAMe, UDCA (100 μM), or farnesoid X receptor agonists. MAFG expression and promoter activity were measured using real-time polymerase chain reaction, immunoblot, and transient transfection. We performed electrophoretic mobility shift, and chromatin immunoprecipitation assays to study proteins that occupy promoter regions. We studied mice with bile-duct ligation, orthotopic cholangiocarcinomas, cholestasis-induced cholangiocarcinoma, diethylnitrosamine-induced liver tumors, and xenograft tumors. RESULTS:LCA activated expression of MAFG in HepG2 and MzChA-1 cells, which required the activator protein-1, nuclear factor-κB, and E-box sites in the MAFG promoter. LCA reduced expression of MAT1A but increased expression of MAT2A in cells. Overexpression of MAT2A increased activity of the MAFG promoter, whereas knockdown of MAT2A reduced it. MAT1A and MAT2A had opposite effects on the activator protein-1, nuclear factor-κB, and E-box-mediated promoter activity. Expression of MAFG and MAT2A increased, and expression of MAT1A decreased, in diethylnitrosamine-induced liver tumors in mice. SAMe and UDCA had shared and distinct mechanisms of preventing LCA-mediated increased expression of MAFG. OCA increased expression of MAFG, MAT2A, and c-MYC, but reduced expression of MAT1A. Incubation of human liver and biliary cancer cells lines with OCA promoted their proliferation; in nude mice given OCA, xenograft tumors were larger than in mice given vehicle. Levels of MAFG were increased in human HCC and cholangiocarcinoma tissues compared with non-tumor tissues. High levels of MAFG in HCC samples correlated with hepatitis B, vascular invasion, and shorter survival times of patients. CONCLUSIONS:Expression of MAFG increases in cells and tissues with cholestasis, as well as in human cholangiocarcinoma and HCC specimens; high expression levels correlate with tumor progression and reduced survival time. SAMe and UDCA reduce expression of MAFG in response to cholestasis, by shared and distinct mechanisms. OCA induces MAFG expression, cancer cell proliferation, and growth of xenograft tumors in mice