Jolkinolide B inhibits the progression of hepatocellular carcinoma by regulating Musashi-2 protein.

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths. However, the HCC treatment is still challenging. Herein, we aimed to reveal the anti-tumor effect of Jolkinolide B in HCC cell lines Huh-7 and SK-Hep-1. The results showed that Jolkinolide B inhibited the migration, invasion, and epithelial-to-mesenchymal transition(EMT) of HCC cells. In addition, Jolkinolide B induced HCC cell apoptosis by upregulating Bax and downregulating BCL-2 expressions. Furthermore, we demonstrated that Jolkinolide B inactivated the ß-catenin signaling and reduced Musashi-2 expression. Finally, we revealed that Musashi-2 overexpression reversed the Jolkinolide B-induced anti-HCC effect. Overall, we proved that Jolkinolide B is a potential candidate for treating HCC.

Does big data serve policy? Not without context. An experiment with in silico social science.

The DARPA Ground Truth project sought to evaluate social science by constructing four varied simulated social worlds with hidden causality and unleashed teams of scientists to collect data, discover their causal structure, predict their future, and prescribe policies to create desired outcomes. This large-scale, long-term experiment of in silico social science, about which the ground truth of simulated worlds was known, but not by us, reveals the limits of contemporary quantitative social science methodology. First, problem solving without a shared ontology-in which many world characteristics remain existentially uncertain-poses strong limits to quantitative analysis even when scientists share a common task, and suggests how they could become insurmountable without it. Second, data labels biased the associations our analysts made and assumptions they employed, often away from the simulated causal processes those labels signified, suggesting limits on the degree to which analytic concepts developed in one domain may port to others. Third, the current standard for computational social science publication is a demonstration of novel causes, but this limits the relevance of models to solve problems and propose policies that benefit from the simpler and less surprising answers associated with most important causes, or the combination of all causes. Fourth, most singular quantitative methods applied on their own did not help to solve most analytical challenges, and we explored a range of established and emerging methods, including probabilistic programming, deep neural networks, systems of predictive probabilistic finite state machines, and more to achieve plausible solutions. However, despite these limitations common to the current practice of computational social science, we find on the positive side that even imperfect knowledge can be sufficient to identify robust prediction if a more pluralistic approach is applied. Applying competing approaches by distinct subteams, including at one point the vast TopCoder.com global community of problem solvers, enabled discovery of many aspects of the relevant structure underlying worlds that singular methods could not. Together, these lessons suggest how different a policy-oriented computational social science would be than the computational social science we have inherited. Computational social science that serves policy would need to endure more failure, sustain more diversity, maintain more uncertainty, and allow for more complexity than current institutions support.

Isolongifolene alleviates liver ischemia/reperfusion injury by regulating AMPK-PGC1α signaling pathway-mediated inflammation, apoptosis, and oxidative stress.

Isolongifolene (ISO) has antioxidant, anti-inflammatory, anticancer, and neuroprotective effects; however, it is unclear whether ISO has a protective effects against liver ischemia/reperfusion (I/R) injury. In this study, a mouse liver I/R injury model and a mouse AML12 cell Hypoxia reoxygenation (H/R) model were established after pretreatment with different concentrations of ISO. Serum transaminase levels, necrotic liver area, cell viability, inflammation response, oxidative stress, and apoptosis were used to evaluate the effect of ISO on liver I/R or cell H/R injury. Western blotting was used to detect Bax, Bcl-2, C-Caspase3, AMPK, P-AMPK, and PGC1α protein expression levels. The AMPK inhibitor, compound C, was used to inhibit the AMPK expression. The results showed that ISO reduced serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, liver necrosis, inflammatory factors IL-1ß, IL-6, MCP-1, and TNF-α expression, MPO+ inflammatory cell infiltration, MDA content, TUNEL-positive cell number, cell apoptosis rate, and the expression of pro-apoptotic proteins Bax and C-Caspase3, while increasing cell viability, SOD and GSH activity, and the expression of anti-apoptotic protein Bcl-2. Moreover, Western blotting results showed that ISO could increase the protein expression of P-AMPK and PGC1α. Following the addition of compound C, the protective effect of ISO was significantly weakened. Therefore, our results suggest that ISO alleviates liver I/R injury by regulating AMPK-PGC1α signaling pathway-mediated anti-inflammatory, and antioxidant and anti-apoptotic effects.

Prognostic factors of recurrent intrahepatic cholangiocarcinoma after hepatectomy: A retrospective study.

BACKGROUND: Intrahepatic cholangiocarcinoma (ICC) is a highly malignant tumour. Hepatectomy is an effective treatment for early ICC, but postoperative recurrence greatly affects patient survival. Studies on recurrent ICC after hepatectomy are lacking. AIM: To investigate the clinical characteristics of patients with recurrent ICC after hepatectomy, analyse prognostic factors and explore diagnosis and treatment strategies. METHODS: A retrospective analysis was performed on all ICC patients undergoing hepatectomy from January 2013 to August 2021. Patients with postoperative recurrence were selected according to the inclusion and exclusion criteria. Cumulative overall survival was plotted by the Kaplan-Meier method, and differences were assessed by univariate survival analysis using the log-rank test. Multivariate analysis of cumulative survival was performed using the Cox proportional risk model. RESULTS: During the 8-year study period, 103 patients underwent ICC-related hepatectomy, and 54 exhibited postoperative recurrence. The median disease-free survival (DFS) was 6 mo, the median overall survival (OS) was 9 mo, and the cumulative OS rates at 1, 2 and 3 years after the operation were 40.7%, 14.8% and 7.4%, respectively. The median OS after recurrence was 4 mo, and the cumulative OS rates at 1, 2 and 3 years after recurrence were 16.1%, 6.7% and 3.4%, respectively. Multivariate analysis showed that alcohol consumption [hazard ratio (HR) = 4.64, 95% confidence interval (CI): 1.53-14.04, P = 0.007] and DFS < 6 mo (HR = 3.47, 95%CI: 1.59-7.60, P = 0.002) were independent risk factors for the cumulative survival of patients with recurrence, while treatment after recurrence (HR = 0.21, 95%CI: 0.08-0.55, P = 0.001) was an independent protective factor. The median OS time of patients receiving multimodality therapy after recurrence of ICC was 7 mo, which was significantly higher than that of patients receiving only local therapy (3 mo), patients receiving systematic therapy (4 mo) and patients receiving the best supportive therapy (1 mo). Patients with recurrent ICC who received multimodality therapy had a significantly better long-term survival after recurrence than those who did not (P = 0.026). CONCLUSION: The prognosis of patients with recurrence after ICC-related hepatectomy is poor. Alcohol consumption and DFS < 6 mo are independent risk factors in terms of the cumulative survival of patients with recurrence, while treatment after recurrence is an independent protective factor. Multimodality therapy can effectively improve the prognosis of patients.

[Variety of the Composition and Sources of VOCs During the Spring Festival and Epidemic Prevention in the Pearl River Delta].

Volatile organic compounds (VOCs) are the key precursors of the ozone (O3) formation processes in the troposphere and are important control objects for the coordinated governance of O3 and PM2.5. The Spring Festival of 2020 was affected by the novel coronavirus (COVID-19) pneumonia epidemic:companies stopped work and production, and traffic was restricted, providing scientific experimentation opportunities for pollutant emission reduction research. This study analyzed the variety of the composition, chemical reaction activity, and sources of VOCs in the Pearl River Delta during the Spring Festival and the epidemic control period, using real-time online monitoring data of VOCs obtained at four sites(Guangzhou, Dongguan, Zhongshan, and Duanfen)in the Pearl River Delta from January 1, 2020 to February 29, 2020. The results showed that during the Spring Festival and the epidemic control period, the average of φ (VOCs) in the Pearl River Delta was 15.89×10-9, and the maximum hourly average concentration was 45.43×10-9, values that were 44% and 60% lower, respectively, than those before the Spring Festival holiday. Among the VOCs component concentration decreases, the aromatic hydrocarbon component decreased the most, and the decrease in the urban area of the Pearl River Delta (74%) was significantly greater than that in the suburban area (56%). As a result, the contribution rate of aromatic hydrocarbons to the total VOCs was reduced to less than 10%. The analysis of the·OH reaction activity of VOCs(L·OH)and ozone formation potential(OFP)showed that the L·OH and OFP of VOCs decreased significantly in the Pearl River Delta during the Spring Festival and the epidemic control period. Compared with those before the Spring Festival holiday, the total L·OH and total OFP decreased by an average of 60% and 63% in the urban area of the Pearl River Delta, respectively. Additionally, the atmospheric oxidation had also been significantly reduced, which showed a 28% decrease in ρ(Ox). The ratio of toluene/benzene showed that the influence of industrial sources had almost disappeared during the Spring Festival and the epidemic control period, and the total points of the representative components of industrial-related solvent-use sources such as toluene, ethylbenzene, and m/p-xylene dropped by 72% to 91%. The results of this study suggest that solvent-use sources and vehicle exhaust emission sources are the current sources of VOCs that need to be paid attention to in the prevention and control of O3 pollution in the Pearl River Delta region, and the impact of petrochemical sources cannot be ignored in the work of further reducing the background concentration of O3.

Blocking protease-activated receptor 4 alleviates liver injury induced by brain death.

Brain death (BD) induces a systemic inflammatory response that influences donor liver quality. Protease-activated receptor 4 (PAR4) is a thrombin receptor that mediates platelet activation and is involved in inflammatory and apoptotic processes. Therefore, we investigated the role of PAR4 blockade in liver injury induced by BD and its associated mechanisms. In this study, we constructed a BD rat model and treated rats with TcY-NH2, a selective PAR4 antagonist, to block PAR4 signaling at the onset of BD induction. Our results revealed that PAR4 protein expression increased in the livers of rats with BD. PAR4 blockade alleviated liver injury induced by BD, as indicated by lower serum ALT/AST levels and an improvement in histomorphology. Blood platelet activation and hepatic platelet accumulation in BD rats were reduced by PAR4 blockade. Additionally, PAR4 blockade attenuated the inflammatory response and apoptosis in the livers of BD rats. Moreover, the activation of NF-κB and MAPK pathways induced by BD was inhibited by PAR4 blockade. Thus, our results suggest that PAR4 contributes to liver injury induced by BD by regulating inflammation and apoptosis through the NF-κB and MAPK pathways. Thus, PAR4 blockade may provide a feasible approach to improve the quality of organs from BD donors.

RNF8 ubiquitinates RecQL4 and promotes its dissociation from DNA double strand breaks.

Ubiquitination-dependent DNA damage response (DDR) signals play a critical role in the cellular choice of DNA damage repair pathways. Human DNA helicase RecQL4 participates in DNA replication and repair, and loss of RecQL4 is associated with autosomal recessive genetic disorders characterized by genomic instability features. In an earlier study, RecQL4 was isolated as a stable complex that contained two ubiquitin ligases of the N-end rule (UBR1 and UBR2). However, it is unknown whether or not RecQL4 ubiquitination status is critical for its DNA repair function. Here, we report that RecQL4 directly interacts with RNF8 (a RING finger ubiquitin E3 ligase), and both co-localize at DNA double-strand break (DSB) sites. Our findings indicate that RNF8 ubiquitinates RecQL4 protein mainly at the lysine sites of 876, 1048, and 1101, thereby facilitating the dissociation of RecQL4 from DSB sites. RecQL4 mutant at ubiquitination sites had a significantly prolonged retention at DSBs, which hinders the recruitment of its direct downstream DSB repair proteins (CtIP & Ku80). Interestingly, reduced DSB repair capacity observed in RecQL4 depleted cells was restored only by the reconstitution of wild-type RecQL4, but not the ubiquitination mutant. Additionally, RecQL4 directly interacts with WRAP53ß that is known to recruit RNF8 to DSBs and WRAP53ß enhances the association of RecQL4 with RNF8. WRAP53ß silencing resulted in a nearly diminished recruitment of RNF8 to DSBs and in a greatly attenuated dissociation of RecQL4 from the DSB sites. Collectively, our study demonstrates that the ubiquitination event mediated by RNF8 constitutes an essential component for RecQL4's function in DSB repair.

Single nucleotide polymorphisms in interleukin-6 attenuates hepatocytes injury in hypoxia/re-oxygenation via STAT3 signal pathway mediated autophagy.

Ischemia-reperfusion injury (IRI) is inevitable during liver surgery, and it is an important factor affecting the prognosis of patients. IL-6 rs1800796 single nucleotide polymorphisms (SNPs) can promote synthesis and secretion of IL-6 and protect hepatocytes from IRI. In this study, we investigated the mechanisms by which IL-6 alleviates hepatic IRI. We transfected lentivirus which carries IL-6 rs1800796 to L02 cells and constructed the cell line (L02-IL6) with a high expression of IL-6. The biological function of IL-6 SNPs was explored through a cell model of hypoxia-reoxygenation (H/R). Cell viability was evaluated by CCK8 and Real-Time Cell Analysis (RTCA), and found that the viability of the L02-IL6 cells was higher than that of the control group (P < 0.01). Flow cytometry assay showed that the rate of apoptosis was significantly decreased in L02-IL6 cells. Furthermore, in comparison with the control group, the level of cleaved-caspase3, which is an important marker of apoptosis, was dramatically decreased. These differences showed that the sequence variants at rs1800796 of the IL-6 gene could improve the resistance against H/R. Moreover, the levels of autophagy-related proteins, such as LC3 and Beclin-1, were upregulated in L02-IL6 group on H/R injury, which means IL-6 could alleviate apoptosis via activating the autophagy pathway. And we also found that the STAT3 signal pathway was activated. Next, we investigated whether the exogenous treatment with IL-6 affect hepatocytes and thus play a protective role. We pre-treated the L02 cells with recombinant human IL-6 for 12 h and then made H/R treatment. We found the treatment with 100 ng/ml IL-6 alleviated the damage of L02 cells and inhibited the apoptosis. And the further study revealed the pre-treatment with IL-6 activated the STAT3 signaling pathway in the L02 cells and then caused the activation of autophagy and apoptosis inhibition. IL-6 might play a critical role in alleviating hepatic IRI, through its modulation of the STAT3 signaling pathway, and activation of autophagy. Recombinant human IL-6 might be a potential therapeutic target in hepatic IRI.

Electrostatic Assembly of Porphyrin-Functionalized Porous Membrane toward Biomimetic Photocatalytic Degradation Dyes.

Porphyrin-based catalytic oxidation is one of the most representative biomimetic catalysis. To mimic the biomimetic catalytic oxidation of nature, a positive charged porous membrane, quaternized polysulfone (QPSf) membrane with spongelike structure, was prepared for supporting meso-tetraphenylsulfonato porphyrin (TPPS). The influence of polymer concentration, coagulation bath, and additives on the structure of the substrate membrane was explored, and the optimized membrane with porosity of 87.1% and water flux of 371 L·m-2·h-1 at 0.1 MPa was obtained. Monolayer TPPS was adsorbed on the QPSf membrane surface by the electrostatic self-assembly approach, and the adsorption process followed the pseudo second-order kinetic model and Langmuir adsorption isotherm equation. The resulting TPPS@QPSf membrane showed excellent visible light response, and the photocatalytic performance for dyes was then enhanced dramatically after TPPS was immobilized on the membrane. The removal efficiencies for rhodamine B (RhB), methylene blue (MB), and methyl orange (MO) were 92.1, 94.1, and 92.1% under visible light irradiation, respectively. The primary photocatalytic degradation of the dye was a zero-order reaction, and the secondary reaction of degradation followed pseudo first-order kinetics. Finally, the TPPS@QPSf membrane can be reused for photocatalytic degradation of RhB for 10 cycles with no obvious change on removal efficiency, which indicated that this membrane is a promising material for dyeing water treatment coupled with visible light irradiation.

Donor Brain Death Leads to a Worse Ischemia-Reperfusion Injury and Biliary Injury After Liver Transplantation in Rats.

BACKGROUND: Brain-dead (BD) donor is the main source for liver transplantation (LT). We aim to investigate the effect of brain death on donor liver inflammatory activity and its association with ischemia-reperfusion (I/R) injury and biliary tract injury after LT. MATERIAL AND METHOD: A brain death model using male Lewis rats was established, in both BD and non-BD groups; livers were harvested for transplantation using a 2-cuff technique. The rats were sacrificed 12 hours (n = 10) or 4 weeks (n = 10) after transplantation. I/R injury and long-term biliary tract injury were observed after transplantation. RESULTS: All rats survived for 4 weeks after transplantation. At 12 hours after BD-donor LT (BDDLT), liver injury worsened; serum transaminases, bilirubin, oxidative stress, inflammatory responses and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining level substantially increased (P < .05). At 4 weeks after BDDLT, serum bilirubin and bile lactate dehydrogenase and γ-glutamyl transpeptidase levels were elevated (P < .05). Biliary fibrosis and epithelial-mesenchymal transition (EMT) were detectable and NDRG1 gene expression was decreased. CONCLUSIONS: These results suggested that brain death-induced inflammatory response in donor organs and resulted in a worse I/R injury and biliary tract injury after LT in rats. The brain death-related biliary tract injury may be associated with the regulation of EMT through NDRG1.

Six-Transmembrane Epithelial Antigen of the Prostate 3 Deficiency in Hepatocytes Protects the Liver Against Ischemia-Reperfusion Injury by Suppressing Transforming Growth Factor-ß-Activated Kinase 1.

BACKGROUND AND AIMS: Hepatic ischemia-reperfusion (I/R) injury remains a major challenge affecting the morbidity and mortality of liver transplantation. Effective strategies to improve liver function after hepatic I/R injury are limited. Six-transmembrane epithelial antigen of the prostate 3 (Steap3), a key regulator of iron uptake, was reported to be involved in immunity and apoptotic processes in various cell types. However, the role of Steap3 in hepatic I/R-induced liver damage remains largely unclear. APPROACH AND RESULTS: In the present study, we found that Steap3 expression was significantly up-regulated in liver tissue from mice subjected to hepatic I/R surgery and primary hepatocytes challenged with hypoxia/reoxygenation insult. Subsequently, global Steap3 knockout (Steap3-KO) mice, hepatocyte-specific Steap3 transgenic (Steap3-HTG) mice, and their corresponding controls were subjected to partial hepatic warm I/R injury. Hepatic histology, the inflammatory response, and apoptosis were monitored to assess liver damage. The molecular mechanisms of Steap3 function were explored in vivo and in vitro. The results demonstrated that, compared with control mice, Steap3-KO mice exhibited alleviated liver damage after hepatic I/R injury, as shown by smaller necrotic areas, lower serum transaminase levels, decreased apoptosis rates, and reduced inflammatory cell infiltration, whereas Steap3-HTG mice had the opposite phenotype. Further molecular experiments showed that Steap3 deficiency could inhibit transforming growth factor-ß-activated kinase 1 (TAK1) activation and downstream c-Jun N-terminal kinase (JNK) and p38 signaling during hepatic I/R injury. CONCLUSIONS: Steap3 is a mediator of hepatic I/R injury that functions by regulating inflammatory responses as well as apoptosis through TAK1-dependent activation of the JNK/p38 pathways. Targeting hepatocytes, Steap3 may be a promising approach to protect the liver against I/R injury.

USP33 deubiquitinates PRKN/parkin and antagonizes its role in mitophagy.

PRKN/parkin activation through phosphorylation of its ubiquitin and ubiquitin-like domain by PINK1 is critical in mitophagy induction for eliminating the damaged mitochondria. Deubiquitinating enzymes (DUBs) functionally reversing PRKN ubiquitination are critical in controlling the magnitude of PRKN-mediated mitophagy process. However, potential DUBs that directly target PRKN and antagonize its pro-mitophagy effect remains to be identified and characterized. Here, we demonstrated that USP33/VDU1 is localized at the outer membrane of mitochondria and serves as a PRKN DUB through their interaction. Cellular and in vitro assays illustrated that USP33 deubiquitinates PRKN in a DUB activity-dependent manner. USP33 prefers to remove K6, K11, K48 and K63-linked ubiquitin conjugates from PRKN, and deubiquitinates PRKN mainly at Lys435. Mutation of this site leads to a significantly decreased level of K63-, but not K48-linked PRKN ubiquitination. USP33 deficiency enhanced both K48- and K63-linked PRKN ubiquitination, but only K63-linked PRKN ubiquitination was significantly increased under mitochondrial depolarization. Further, USP33 knockdown increased both PRKN protein stabilization and its translocation to depolarized mitochondria leading to the enhancement of mitophagy. Moreover, USP33 silencing protects SH-SY5Y human neuroblastoma cells from the neurotoxin MPTP-induced apoptotic cell death. Our findings convincingly demonstrate that USP33 is a novel PRKN deubiquitinase antagonizing its regulatory roles in mitophagy and SH-SY5Y neuron-like cell survival. Thus, USP33 inhibition may represents an attractive new therapeutic strategy for PD patients.Abbreviations: CCCP: carbonyl cyanide 3-chlorophenylhydrazone; DUB: deubiquitinating enzymes; MPTP: 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine; OMM: outer mitochondrial membrane; PD: Parkinson disease; PINK1: PTEN induced kinase 1; PRKN/PARK2: parkin RBR E3 ubiquitin protein ligase; ROS: reactive oxygen species; TM: transmembrane; Ub: ubiquitin; UBA1: ubiquitin like modifier activating enzyme 1; UBE2L3/UbcH7: ubiquitin conjugating enzyme E2 L3; USP33: ubiquitin specific peptidase 33; WT: wild type.

Microarray Analysis For Expression Profiles of lncRNAs and circRNAs in Rat Liver after Brain-Dead Donor Liver Transplantation.

The mechanisms underlying severe liver injury after brain-dead (BD) donor liver transplantation (BDDLT) remain unclear. In this study, we aimed to explore the roles of lncRNAs and circRNAs in liver injury after BDDLT. Rat liver injury was detected in the sham, BD, control, and BDDLT groups. We examined the expression profiles of lncRNAs and circRNAs in the livers of the BDDLT and control group using microarray analysis. The main functions of the differentially expressed genes were analyzed by gene ontology (GO) and KEGG pathway enrichment analysis. In addition, we used bioinformatic analyses to construct related expression networks. Liver injury was aggravated in the BD and BDDLT groups. We found various mRNAs, lncRNAs, and circRNAs that were differentially expressed in the BDDLT group compared with those in the control group. Coding-noncoding gene co-expression (CNC) network analysis showed that expression of the lncRNA LOC102553657 was associated with that of the apoptosis-related genes including HMOX1 and ATF3. Furthermore, competing endogenous RNAs (ceRNAs) network analysis revealed that the lncRNA LOC103692832 and rno_circRNA_007609 were ceRNAs of rno-miR-135a-5p targeting Atf3, Per2, and Mras. These results suggest that lncRNAs and circRNAs play important roles in the pathogenesis and development of liver injury during BDDLT.

Natural constituents of St. John's Wort inhibit the proteolytic activity of human thrombin.

Thrombin, a multifunctional serine protease responsible for the proteolytic hydrolysis of soluble fibrinogen, plays a pivotal role in the blood coagulation cascade. Currently, thrombin inhibitor therapy has been recognized as an effective therapeutic strategy for the prevention and treatment of thrombotic diseases. In this study, the inhibitory effects of natural constituents in St. John's Wort against human thrombin are carefully investigated by a fluorescence-based biochemical assay. The results clearly demonstrate that most of naphthodianthrones, flavonoids and biflavones exhibit strong to moderate inhibition on human thrombin. Among all tested compounds, hypericin shows the most potent inhibitory capability against thrombin, with the IC50 value of 3.00 µM. Further investigation on inhibition kinetics demonstrates that hypericin is a potent and reversible inhibitor against thrombin-mediated Z-GGRAMC acetate hydrolysis, with the Ki value of 2.58 µM. Inhibition kinetic analyses demonstrate that hypericin inhibits thrombin-mediated Z-GGRAMC acetate hydrolysis in a mixed manner, which agrees well with the results from docking simulations that hypericin can bind on both catalytic cavity and anion binding exosites. All these findings suggest that hypericin is a natural thrombin inhibitor with a unique dianthrone skeleton, which can be used as a good candidate to develop novel thrombin inhibitors with improved properties.

RecQL4-Aurora B kinase axis is essential for cellular proliferation, cell cycle progression, and mitotic integrity.

Human RecQL4 helicase plays critical roles in the maintenance of genomic stability. Mutations in RecQL4 helicase results in three clinically related autosomal recessive disorders: Rothmund-Thomson syndrome (RTS), RAPADILINO, and Baller-Gerold syndrome. In addition to several premature aging features, RTS patients are characterized by aneuploidy involving either loss or gain of a single chromosome. Chromosome mosaicism and isochromosomes involving chromosomes 2, 7, and 8 have been reported in RecQL4-deficient RTS patients, but the precise role of RecQL4 in chromosome segregation/stability remains to be elucidated. Here, we demonstrate that RecQL4 physically and functionally interacts with Aurora B kinase (AURKB) and stabilizes its expression by inhibiting its ubiquitination process. Our study indicates that the N-terminus of RecQL4 interacts with the catalytic domain of AURKB. Strikingly, RecQL4 suppression reduces the expression of AURKB leading to mitotic irregularities and apoptotic cell death. RecQL4 suppression increases the proportion of cells at the G2/M phase followed by an extensive cell death, presumably owing to the accumulation of mitotic irregularities. Both these defects (accumulation of cells at G2/M phase and an improper mitotic exit to sub-G1) are complemented by the ectopic expression of AURKB. Finally, evidence is provided for the requirement of both human telomerase reverse transcriptase and RecQL4 for stable immortalization and longevity of RTS fibroblasts. Collectively, our study suggests that the RecQL4-AURKB axis is essential for cellular proliferation, cell cycle progression, and mitotic stability in human cells.

Kupffer cell depletion by gadolinium chloride aggravates liver injury after brain death in rats.

Brain death (BD) impairs liver function in potential donors, and is associated with hormonal and metabolic changes or molecular effects with pro­inflammatory activation. Resident macrophages in the liver named Kupffer cells (KCs) undergo pro­ or anti­inflammatory pathway activation, which affects liver function. However, the role of the KCs in liver dysfunction following BD has not been fully elucidated. The aim of the present study was to investigate the role of KCs in liver dysfunction in the context of BD and the effects of their inhibition by gadolinium chloride (GdCl3). Rats were randomly divided into the following groups: Control, BD with GdCl3 pretreatment and BD with normal saline pretreatment. Liver function, hepatic pathological histology and cytokine levels in the liver were assessed. Apoptosis and apoptosis­related proteins [cleaved caspase­3, caspase­3 and apoptosis regulator Bcl­2 (Bcl­2)] were evaluated. GdCl3 significantly aggravated liver injury by elevating alanine aminotransferase and aspartate aminotransferase levels (P<0.05) by inhibiting KCs. Interleukin (IL)­1ß and tumor necrosis factor α levels in the GdCl3 group were significantly increased compared with those in the control and saline groups (P<0.01). However, IL­10 levels in the GdCl3 group were significantly reduced compared with those in the saline group (P<0.05). Caspase­3 and cleaved caspase­3 activation, and apoptosis induction in the context of BD were also significantly aggravated by the depletion of KCs, whereas Bcl­2 was significantly suppressed by the administration of GdCl3. The present study indicated that GdCl3 efficiently inhibits the activity of KCs, and is involved in the onset of liver injury through its effects on pro­inflammatory and anti­inflammatory activation. KCs are protective in the liver in the context of BD. This protection appears to be due to KCs secretion of the potent anti­inflammatory cytokine IL­10, suggesting that KCs are an attractive target for the prevention and treatment of liver injury in the context of BD in rats.

MMS19 localizes to mitochondria and protects the mitochondrial genome from oxidative damage.

MMS19 localizes to the cytoplasmic and nuclear compartments involved in transcription and nucleotide excision repair (NER). However, whether MMS19 localizes to mitochondria, where it plays a role in maintaining mitochondrial genome stability, remains unknown. In this study, we provide the first evidence that MMS19 is localized in the inner membrane of mitochondria and participates in mtDNA oxidative damage repair. MMS19 knockdown led to mitochondrial dysfunctions including decreased mtDNA copy number, diminished mtDNA repair capacity, and elevated levels of mtDNA common deletion after oxidative stress. Immunoprecipitation - mass spectrometry analysis identified that MMS19 interacts with ANT2, a protein associated with mitochondrial ATP metabolism. ANT2 knockdown also resulted in a decreased mtDNA repair capacity after oxidative damage. Our findings suggest that MMS19 plays an essential role in maintaining mitochondrial genome stability.

Inhibition of Endoplasmic Reticulum Stress Alleviates Lung Injury Induced by Brain Death.

Brain death (BD) can induce inflammation and injury of organs. Endoplasmic reticulum (ER) stress is associated with a variety of diseases. However, little is known about how ER stress is implicated in brain death (BD)-induced lung injury. In this study, a stable BD rat model was constructed to investigate the role of ER stress on BD-induced lung injury. H&E staining demonstrated that BD can induce lung injury in rats. The results of Western blot and immunohistochemistry showed that apoptosis was observed in the lung tissues of BD rats. And the level of GRP78, p-PERK, p-eIF2α, CHOP, and Caspase-12 was highly expressed in BD rats compared with the control group. Inhibition of ER stress with salubrinal reduced the BD-induced lung inflammation. Moreover, BD-induced increase of NF-κB activity was lowered by inhibition of ER stress. These results suggested that inhibition of ER stress alleviates BD-induced lung inflammation by regulating NF-κB signaling pathway.

[Effects and mechanism of bFGF on rat myoblast oxidative injury induced by hydrogen peroxide].

OBJECTIVE: To explore the protective role of basic fibroblast growth factor (bFGF) on attenuating hydrogen peroxide-induced injury in cultured rat myoblasts. METHODS: Cultured rat myoblasts at growth phase were randomly divided into four groups (n=6):control group (control), bFGF group (bFGF), model group(H2O2) and the treatment group (bFGF + H2O2). Model group was treated with 100 µmol/L hydrogen peroxide for 4h. B-cell lymphoma-2 (Bcl-2) positive particles were detected by immunohistochemistry; Reactive oxygen species (ROS) and expression for Bcl-2 associated X protein (Bax), Bcl-2 and Cytochrome C (Cyt. C) fluorescence were observed under the invented microscope; Cyt. C and Poly ADP-ribose polymerase(PARP)protein were assessed by Western blot. RESULTS: Compared with control group, the myoblats in the model group showed low expression of Bcl-2 positive particles, accompanied by high expression of ROS level and Cyt. C fuorescence (P < 0.05); Compared with model group, bFGF enhanced Bcl-2 activity of the myoblasts, and significantly downregulated Cyt. C and PARP expression (P < 0.05). CONCLUSIONS: bFGF could attenuate oxidative injury of rat myoblasts induced by hydrogen peroxide, which mechanism might be related to enhanced Bcl-2 and reduced ROS, Cyt. C levels.

RecQL4 regulates autophagy and apoptosis in U2OS cells.

RecQL4, one of the 5 human RecQ helicases, is a key mediator of genomic stability and its deficiency can cause premature aging phenotypes. Here, by using CRISPR/Cas and RNAi technology, we demonstrated that autophagy level was elevated in both RecQL4 knockdown and knockout cells compared with those of the control cells. Surprisingly, mitochondrial content was increased and LC3 co-localization with mitochondria was partially lost in RecQL4 knockout cells compared with the control cells, suggesting that RecQL4 deficiency impaired mitophagic processes in U2OS cells. Furthermore, we found that knockout of RecQL4 destabilized PINK1. In addition, RecQL4 knockout cells were more susceptible to apoptosis under mitochondrial stress than the control cells. In conclusion, our findings indicated a novel role of RecQL4 in the regulation of autophagy/mitophagy in U2OS cells.