Best evidence summary for prevention and management of enteral feeding intolerance in critically ill patients.

AIM: To evaluate and summarize the evidence for prevention and management of enteral feeding intolerance in critically ill patients and provide reference for clinical practice. DESIGN: This study was an evidence summary followed by the evidence summary reporting standard of Fudan University Center for Evidence-based Nursing. METHODS: Current literatures were systematically searched for the best evidence for prevention and management of enteral feeding intolerance in critically ill patients. Literature types included clinical guidelines, best practice information sheets, expert consensuses, systematic reviews, evidence summaries and cohort studies. DATA SOURCES: UpToDate, BMJ Best Practice, Joanna Briggs Institute, Guidelines International Network, National Institute for Health and Care Excellence, Registered Nurses Association of Ontario, Scottish Intercollegiate Guidelines Network, the Cochrane Library, Embase, PubMed, Sinomed, Web of Science, Yi Maitong Guidelines Network, DynaMed, MEDLINE, CNKI, WanFang database, Chinese Medical Journal Full-text Database, European Society for Clinical Nutrition and Metabolism website, the American Society for Parenteral and Enteral Nutrition website were searched from January 2012 to April 2023. RESULTS: We finally identified 18 articles that had high-quality results. We summarized the 24 pieces of best evidence from these articles, covering five aspects: screening and assessment of the risk of enteral nutritional tolerance; formulation of enteral nutrition preparations; enteral nutritional feeding implementation; feeding intolerance symptom prevention and management; and multidisciplinary management. Of these pieces of evidence, 19 were 'strong' and 5 were 'weak', 7 pieces of evidence were recommended in level one and 4 pieces of evidence were recommended in level two. CONCLUSION: The following 24 pieces of evidence for prevention and management of enteral feeding intolerance in critically ill patients were finally recommended. However, as these evidences came from different countries, relevant factors such as the clinical environment should be evaluated before application. Future studies should focus on more specific symptoms of feeding intolerance and more targeted prevention design applications. IMPLICATIONS FOR THE PROFESSION AND PATIENT CARE: The clinical medical staffs are recommended to take evidence-based recommendations for the implementation of standardized enteral nutrition to improve patient outcomes and decrease gastrointestinal intolerance in critically ill patients. IMPACT: The management of enteral nutrition feeding intolerance has always been a challenge and difficulty in critically ill patients. This study summarizes 24 pieces of the best evidence for prevention and management of enteral nutrition feeding intolerance in critically ill patients. Following and implementing these 24 pieces of evidence is beneficial to the prevention and management of feeding intolerance in clinical practice. The 24 pieces of evidence include five aspects, including screening and assessment of the risk of enteral nutritional tolerance, formulation of enteral nutrition preparations, enteral nutritional feeding implementation, feeding intolerance symptom prevention and management and multidisciplinary management. These five aspects constitute a good implementation process. Screening and assessment of enteral nutritional tolerance throughout intervention are important guarantees for developing a feasible nutrition program in critically ill patients. This study will be benefit to global medical workers in the nutritional management of critically ill patients. REPORTING METHOD: This evidence summary followed the evidence summary reporting specifications of Fudan University Center for Evidence-based Nursing, which were based on the methodological process for the summary of the evidence produced by the Joanna Briggs Institute (JBI). The reporting specifications include problem establishment, literature retrieval, literature screening, literature evaluation, the summary and grading of evidence and the formation of practical suggestions. This study was based on the evidence summary reporting specifications of the Fudan University Center for the Evidence-based Nursing, the register name is 'Best evidence summary for prevention and management of enteral feeding intolerance in critically ill patients', the registration number is 'ES20231823'.

Reliability and validity assessment of the Chinese version of the Intrahospital Transport Safety Scale (IHTSS) in intensive care units.

BACKGROUND: Intrahospital transport of critically ill patients is a common practice in intensive care units (ICUs), where patients' safety is constantly challenged in high-intensity and dynamic environments. While Intrahospital Transport Safety Scale (IHTSS) is widely used internationally to evaluate the intrahospital transport safety, it has not been introduced in China. OBJECTIVES: This study aimed to assess the reliability and validity of the Chinese version of the IHTSS scale among critical care nurses in China. METHODS: A cross-sectional study was conducted using a cluster sampling method. A total of 544 critical care nurses from 25 ICUs in 10 tertiary hospitals were recruited. We employed exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) to examine the questionnaire's underlying factor structure, ensuring construct validity. Additionally, internal consistency was assessed using Cronbach's alpha coefficient, test-retest reliability, and corrected item-total correlation. RESULTS: The Chinese version of the scale displayed robust psychometric properties, with a Cronbach's α coefficient of 0.976, a split-half reliability of 0.906, and a test-retest reliability of 0.856. EFA revealed a robust four-factor model that accounted for 75.970% of the variance, with the factor loadings of the items ranging from 0.433 to 0.951. CFA indicated a strong model fit, with a chi-square to degrees of freedom ratio (CMIN/DF) of 2.765, comparative fit index (CFI) of 0.943, incremental fit index (IFI) of 0.943, and goodness-of-fit index (GFI) of 0.845, supporting the efficacy of the four-factor model in assessing intrahospital transport safety for critically ill patients. CONCLUSION: The Chinese version of the IHTSS demonstrated favourable reliability and validity among critical care nurses in China, making it a suitable tool for measuring the level of intrahospital transport safety for critically ill patients.

Moral courage, job-esteem, and social responsibility in disaster relief nurses.

BACKGROUND: Social responsibility can motivate disaster relief nurses to devote themselves to safeguarding rights and interests of people when facing challenges that threaten public health. However, few studies focused on the relationship of moral courage, job-esteem, and social responsibility among disaster relief nurses. OBJECTIVE: To explore the influence of moral courage and job-esteem on the social responsibility in disaster relief nurses and clarify the relationship model between them. METHODS: A cross-sectional study was conducted among 716 disaster relief nurses from 14 hospitals in central China through an online survey, including moral courage scale, job-esteem scale, and social responsibility questionnaire. The data were analyzed by Pearson's correlation, and the mechanism of the effect of moral courage and job-esteem on social responsibility was completed. ETHICAL CONSIDERATIONS: This study was approved by the Medical Ethics Committee of the Second Xiangya Hospital of Central South University (Approval Number: 2019016). RESULTS: Disaster relief nurses' moral courage positively impacted social responsibility (r = 0.677, p < 0.01), and moral courage could affect social responsibility through the mediating role of job-esteem. CONCLUSION: Job-esteem mediated between moral courage and social responsibility among disaster relief nurses. Nursing managers regular assessment of nurses' moral courage and interventions such as meetings and workshops can reduce moral distress, foster morally courageous behavior, enhance job-esteem, and improve social responsibility performance among disaster relief nurses.

ISG15 is downregulated by KLF12 and implicated in maintenance of cancer stem cell-like features in cisplatin-resistant ovarian cancer.

Drug resistance is often developed during clinical chemotherapy of ovarian cancers. The ubiquitin-like protein interferon-stimulated gene 15 (ISG15) is possibly dependent on tumour context to promote or suppress progression of various tumours. The ubiquitin-like protein interferon-stimulated gene 15 (ISG15) was decreased in cisplatin-resistant ovarian cancer cells. The current study identified that both ectopic wild type and nonISGylatable mutant ISG15 expression inhibited CSC-like phenotypes of cisplatin-resistant ovarian cancer cells. Moreover, ectopic ISG15 expression suppressed tumour formation in nude mice. In addition, ISG15 downregulation promoted CSC-like features of cisplatin-sensitive ovarian cancer cells. Furthermore, low ISG15 expression was associated with poor prognosis in patients with ovarian cancer. Transcriptional repressor Krüppel-like factor 12 (KLF12) downregulated ISG15 in cisplatin-resistant cells. Our data indicated that downregulating ISG15 expression, via weakening effect of KLF12, might be considered as new therapeutic strategy to inhibit CSC phenotypes in the treatment of cisplatin-resistant ovarian cancer.

p53-dependent transcriptional suppression of BAG3 protects cells against metabolic stress via facilitation of p53 accumulation.

Solid tumour frequently undergoes metabolic stress during tumour development because of inadequate blood supply and the high nutrient expenditure. p53 is activated by glucose limitation and maintains cell survival via triggering metabolic checkpoint. However, the exact downstream contributors are not completely identified. BAG3 is a cochaperone with multiple cellular functions and is implicated in metabolic reprogramming of pancreatic cancer cells. The current study demonstrated that glucose limitation transcriptionally suppressed BAG3 expression in a p53-dependent manner. Importantly, hinderance of its down-regulation compromised cellular adaptation to metabolic stress triggered by glucose insufficiency, supporting that BAG3 might be one of p53 downstream contributors for cellular adaptation to metabolic stress. Our data showed that ectopic BAG3 expression suppressed p53 accumulation via direct interaction under metabolic stress. Thereby, the current study highlights the significance of p53-mediated BAG3 suppression in cellular adaptation to metabolic stress via facilitating p53 accumulation.

BAG3-positive pancreatic stellate cells promote migration and invasion of pancreatic ductal adenocarcinoma.

BAG3 is constitutively expressed in multiple types of cancer cells and its high expression is associated with tumour progression and poor prognosis of PDAC. However, little is known about the role of BAG3 in the regulation of stromal microenvironment of PDAC. The current study demonstrated that beside PDAC tumour cells, BAG3 was also expressed in some activated stroma cells in PDAC tissue, as well as in activated PSCs. In addition, the current study demonstrated that BAG3 expression in PSCs was involved in maintenance of PSCs activation and promotion of PDACs invasion via releasing multiple cytokines. The current study demonstrated that BAG3-positive PSCs promoted invasion of PDACs via IL-8, MCP1, TGF-ß2 and IGFBP2 in a paracrine manner. Furthermore, BAG3 sustained PSCs activation through IL-6, TGF-ß2 and IGFBP2 in an autocrine manner. Thereby, the current study provides a new insight into the involvement of BAG3 in remodelling of stromal microenvironment favourable for malignant progression of PDAC, indicating that BAG3 might serve as a potential target for anti-fibrosis of PDAC.

Sestrin 2 protects against metabolic stress in a p53-independent manner.

Glucose limitation activates p53, which functions as an adaptive response to maintain cell survival. However, p53 is frequently deleted or mutated in a variety of tumors, while most cancer cells can acclimatize themselves to metabolically unfavorable surrounding, indicating that alternative mechanisms other than p53 transactivation underly adaptive response of cancer cells with p53 deletion or mutation to metabolically hostile environment. Sestrin 2 (SESN2) is a p53 downstream target, which plays a protective role against various stressful stimuli, such as genotoxic, energetic, and oxidative stress. In the current study, we demonstrated that SESN2 transcript was stabilized by glucose limitation at the posttranscriptional level irrespective of p53 status. Importantly, SESN2 also protected cells from metabolic stress triggered by glucose limitation in a p53-independent manner. Our data indicated that stabilization of SESN2 transcript might be an alternative adaptive response to metabolic stress other than p53 activation. Thereby, the current study highlights the significance of stabilization of SESN2 transcript in adaptation of cells with p53 deletion or mutation to metabolic stress.

Effects of NH4+-N and NO2--N on carbon fixation in an anaerobic ammonium oxidation reactor.

Inorganic carbon (IC) is used as a carbon source of the anaerobic ammonium oxidation (anammox) microorganisms during the anammox process. Meanwhile, anammox microorganisms possess a certain carbon fixation capacity. In this study, the effects of NH4+-N and NO2--N on carbon fixation in an anammox reactor were investigated. The carbon fixation content had a positive correlation with the amount of NH4+-N and NO2--N. A high carbon sequestration of 6.52 mg-C and relatively low CO2 emissions of 1.00 mg-C were caused by a high amount of influent nitrogen. The microbiology analysis showed that there was a significant relevance between the abundance of the cbbLR1 gene and the carbon fixation content. The results revealed that the Calvin cycle pathway for carbon fixation was used by the anammox bacteria, which may be uncultured Bacillus sp. clone TA_17 or uncultured Methylobacterium sp. clone LA8_13.

BAG3 promotes proliferation of ovarian cancer cells via post-transcriptional regulation of Skp2 expression.

Bcl-2 associated athanogene 3 (BAG3) contains a modular structure, through which BAG3 interacts with a wide range of proteins, thereby affording its capacity to regulate multifaceted biological processes. BAG3 is often highly expressed and functions as a pro-survival factor in many cancers. However, the oncogenic potential of BAG3 remains not fully understood. The cell cycle regulator, S-phase kinase associated protein 2 (Skp2) is increased in various cancers and plays an important role in tumorigenesis. The current study demonstrated that BAG3 promoted proliferation of ovarian cancer cells via upregulation of Skp2. BAG3 stabilized Skp2 mRNA via its 3'-untranslated region (UTR). The current study demonstrated that BAG3 interacted with Skp2 mRNA. In addition, miR-21-5p suppressed Skp2 expression, which was compromised by forced BAG3 expression. These results indicated that at least some oncogenic functions of BAG3 were mediated through posttranscriptional regulation of Skp2 via antagonizing suppressive action of miR-21-5p in ovarian cancer cells.

Transmission of measles among healthcare Workers in Hospital W, Xinjiang Autonomous Region, China, 2016.

BACKGROUND: As China approaches the elimination of measles, outbreaks of measles continue to occur. Healthcare workers (HCWs) are known to be at high risk of infection and transmission of measles virus. A measles outbreak occurred in a hospital in Xinjiang Uighur Autonomous Region of the People's Republic of China. We report an investigation of this outbreak and its implications for measles elimination and outbreak preparedness. METHODS: We conducted a retrospective search for measles cases using hospital records. Information on cases was collected by interview, and was used to determine epidemiological linkages. We surveyed HCWs to determine their demographic characteristics, disease history and vaccination status, and knowledge about measles. RESULTS: We identified 19 cases, ages 18 to 45 years, in Hospital W between December 2015 and January 2016; 14 were laboratory-confirmed, and 5 were epidemiologically linked. The primary case was a 25-year-old neurology department nurse who developed a rash on 22 December 2015 that was reported on 11 January 2016. She continued working and living with her workmates in a dormitory during her measles transmission period. Among the 19 infected HCWs, 2 had received a dose of measles-containing vaccine (MCV) before the outbreak, and 16 had unknown vaccination status. Outbreak response immunization activities were started on 8 January in a non-selective manner by offering vaccine regardless of vaccination history; 605(68%) of 890 HCWs were vaccinated. The HCW survey had a 73% response rate (646/890); 41% of HCWs reported that they had received MCV before outbreak, and 56% exhibited good knowledge of measles symptoms, transmission, complications, and vaccination. CONCLUSIONS: Low MCV coverage, low measles knowledge among HCWs, delayed reporting of measles cases, and absence of proper case management were associated with this outbreak. Training and vaccinating HCWs against measles are essential activities to prevent measles virus transmission among HCWs.

Advanced glycation end products promote proliferation and suppress autophagy via reduction of Cathepsin D in rat vascular smooth muscle cells.

Autophagy is closely involved in vascular smooth muscle cell (VSMC) function, but little is known about the association between advanced glycation end products (AGEs) and autophagy and its role in AGEs-induced proliferation and migration of VSMCs. The current study investigated the effects of AGEs on the phenotypic modulation and autophagy of VSMCs, as well as the potential underlying mechanisms. Primary rat VSMCs were treated with bovine serum albumin or AGEs. Cell proliferation was detected by MTT assay, real-time cell analyzer and EdU incorporation. Cell cycle was analyzed by Hoechst staining and flow cytometry. The migration of VSMCs was detected by wound-healing assay and transwell migration assay. LC3 transition and p62 accumulation were detected using Western blotting. Acidic vacuoles were measured using AO and MDC staining. Cathepsin D (CatD) was transduced to VSMCs via lentiviral vectors. AGEs enhanced proliferation and migration of primary rat VSMC in a time-dependent manner. AGEs significantly increased LC3-II transition and p62 expression, as well as accumulation of acidic vacuole, which was not further increased by bafilomycin A1. AGEs decreased CatD expression in a time-dependent pattern, and overexpression of CatD prohibited autophagy attenuation mediated by AGEs. CatD overexpression suppressed AGEs-induced proliferation of VSMCs. Nevertheless, CatD exhibited no effects on AGEs-induced migration of VSMCs. AGEs promote proliferation of VSMCs and suppress autophagy, at least in part via CatD reduction.

BAG3 is upregulated by c-Jun and stabilizes JunD.

BAG3 plays a regulatory role in a number of cellular processes, including cell proliferation, apoptosis, adhesion and migration, epithelial-mesenchymal transition (EMT), autophagy activation, and virus infection. The AP-1 transcription factors are implicated in a variety of important biological processes including cell differentiation, proliferation, apoptosis and oncogenesis. Recently, it has been reported that AP-1 protein c-Jun inhibits autophagy and enhances apoptotic cell death mediated by starvation. However, the molecular mechanisms remain unclear. For the first time, the current study demonstrated that serum starvation downregulated BAG3 at the transcriptional level via c-Jun. In addition, the current study reported that BAG3 stabilized JunD mRNA, which was, at least in part, responsible for the promotion of serum starvation mediated-growth inhibition by BAG3.

BAG3 sensitizes cancer cells exposed to DNA damaging agents via direct interaction with GRP78.

Bcl-2 associated athanogene 3 (BAG3) has a modular structure that contains a BAG domain, a WW domain, a proline-rich (PxxP) domain to mediate potential interactions with chaperons and other proteins that participate in more than one signal transduction. In search for novel interacting partners, the current study identified that 78kDa glucose-regulated protein (GRP78) was a novel partner interacting with BAG3. Interaction between GRP78 and BAG3 was confirmed by coimmunoprecipitation and glutathione S-transferase (GST) pulldown. We also identified that the ATPase domain of GRP78 and BAG domain of BAG3 mediated their interaction. Counterintuitive for a prosurvival protein, BAG3 was found to promote the cytotoxicity of breast cancer MCF7, thyroid cancer FRO and glioma U87 cells subjected to genotoxic stress. In addition, the current study demonstrated that BAG3 interfered with the formation of the antiapoptotic GRP78-procaspase-7 complex, which resulted in an increased genotoxic stress-induced cytotoxicity in cancer cells. Furthermore, overexpression of GRP78 significantly blocked the enhancing effects of BAG3 on activation of caspase-7 and induction of apoptosis by genotoxic stress. Overall, these results suggested that through direct interaction BAG3 could prevent the antiapoptotic effect of GRP78 upon genotoxic stress.

Azocinoindole synthesis by a gold(I)-catalyzed ring expansion of 2-propargyl-ß-tetrahydrocarboline.

A new methodology taking advantage of gold(I)-catalyzed ring expansion has been developed to assemble tricyclic 1H-azocino[5,4-b]indoles from 2-propargyl-ß-tetrahydrocarbolines. The azocinoindoles were obtained in moderate to excellent yields; the structure of which was established by X-ray crystallographic analysis. A mechanism involving regioselective intramolecular hydroarylation, [1,2]-alkenyl migration and carbon-carbon bond-fragmentation was proposed.

O-GlcNAcylation of TRIM29 and OGT translation forms a feedback loop to promote adaptive response of PDAC cells to glucose deficiency.

PURPOSE: Glucose not only provides energy for tumor cells, but also provides various biomolecules that are essential for their survival, proliferation and invasion. Therefore, it is of great clinical significance to understand the mechanism of how tumor cells adapt to metabolic stress and maintain their survival. The aim of this research was to study the critical role of OGT and TRIM29 O-GlcNAc modification driven adaptability of PDAC cells to low glucose stress, which might have important medical implications for PDAC therapy. METHODS: Western blotting, mass spectrometry and WGA-immunoprecipitation were used to examined the levels of OGT and O-GlcNAc glycosylated proteins in BxPC3 and SW1990 cells in normal culture and under glucose deprivation conditions. Crystal violet assay, flow cytometry, RIP, RT-qPCR, protein stability assay, biotin pull down were used to investigate the mechanism of OGT and TRIM29-mediated adaptive response to glucose deficiency in PDAC cells. RESULTS: The current study found that under the condition of low glucose culture, the levels of OGT and O-GlcNAc glycosylation in PDAC cells were significantly higher than those in normal culture. Moreover, the high expression of OGT has a protective effect on PDAC cells under low glucose stress. This study confirmed that there was no significant change in mRNA level and protein degradation of OGT under low glucose stress, which was mainly reflected in the increase of protein synthesis. In addition, O-GlcNAc modification at T120 site plays a critical role in the metabolic adaptive responses mediated by TRIM29. CONCLUSIONS: Taken together, our study indicated that O-GlcNAcylation of TRIM29 at T120 site and OGT translation forms a loop feedback to facilitate survival of PDAC under glucose deficiency.

Implication of Nrf2 and ATF4 in differential induction of CHOP by proteasome inhibition in thyroid cancer cells.

Proteasome inhibition may cause endoplasmic reticulum (ER) stress, which has been reported to be implicated in the antitumoral effects of proteasome inhibitors. CCAAT/enhancer-binding protein homologous protein (CHOP) is induced by a variety of adverse physiological conditions including ER stress and is involved in apoptosis. We have reported that distinct induction of CHOP contributes to the responsiveness of thyroid cancer cells to proteasome inhibitors. However, the mechanism underlying differential induction of CHOP by proteasome inhibitors in thyroid cancer cells has not been well characterized. In the current study, we characterized that proteasome inhibition primarily activated the amino acid response element 1 (AARE1) on the CHOP promoter. We also demonstrated that although proteasome inhibition caused similar accumulation of activating transcription factor 4 (ATF4) in a panel of thyroid cancer cells, distinct amounts of ATF4 were recruited to the AARE1 element of CHOP promoter. In addition, we demonstrated that NF-E2-related factor 2 (Nrf2) was also implicated in the induction of CHOP by precluding the binding of ATF4 to the CHOP promoter. This study highlights the molecular mechanisms by which ATF4 and Nrf2 can control CHOP induction in thyroid cancer cells by proteasome inhibition.

Implication of 14-3-3ε and 14-3-3θ/τ in proteasome inhibition-induced apoptosis of glioma cells.

Proteasome inhibitors represent a novel class of anticancer agents that are used in the treatment of hematologic malignancies and various solid tumors. However, mechanisms underlying their anticancer actions were not fully understood. It has been reported that strong 14-3-3 protein expression is observed and associated with tumor genesis and progression of astrocytoma. In addition, global inhibition of 14-3-3 functions with a general 14-3-3 antagonist difopein induces apoptosis of human astrocytoma cells, validating 14-3-3 as a potential molecular target for anticancer therapeutic management. In the current study, for the first time we demonstrated that proteasome inhibitors downregulated 14-3-3ε and 14-3-3θ/τ in U87 and SF295 glioma cells. Overexpression of 14-3-3ε and 14-3-3θ/τ significantly suppressed apoptosis of human glioma cells induced by proteasome inhibitors. We also demonstrated that MG132 activated ASK1 and siASK1 compromised the MG132-induced apoptosis of glioma cells. Furthermore, overexpression of 14-3-3ε and 14-3-3θ/τ markedly suppressed activation of ASK1. Collectively, the current study supported that proteasome inhibitors, at least in part, caused cytotoxicity of glioma cells via downregulation of 14-3-3ε and 14-3-3θ/τ and subsequent activation of ASK1.

Involvement of JNK and NF-κB pathways in lipopolysaccharide (LPS)-induced BAG3 expression in human monocytic cells.

Lipopolysaccharide (LPS) is an outer-membrane glycolipid component of Gram-negative bacteria known for its fervent ability to activate monocytic cells and for its potent proinflammatory capabilities. Bcl-2-associated athanogene 3 (BAG3) is a survival protein that has been shown to be stimulated during cell response to stressful conditions, such as exposure to high temperature, heavy metals, proteasome inhibition, and human immunodeficiency virus 1 (HIV-1) infection. In addition, BAG3 regulates replication of Varicella-Zoster Virus (VZV) and Herpes Simplex Virus (HSV) replication, suggesting that BAG3 could participate in the host response to infection. In the current study, we found that LPS increased the expression of BAG3 in a dose- and time-dependent manner. Actinomycin D completely blocked the LPS-induced BAG3 accumulation, as well as LPS activated the proximal promoter of BAG3 gene, supported that the induction by LPS occurred at the level of gene transcription. LPS-induced BAG3 expression was blocked by JNK or NF-κB inhibition, suggesting that JNK and NF-κB pathways participated in BAG3 induction by LPS. In addition, we also found that induction of BAG3 was implicated in monocytic cell adhesion to extracellular matrix induced by LPS. Overall, the data support that BAG3 is induced by LPS via JNK and NF-κB-dependent signals, and involved in monocytic cell-extracellular matrix interaction, suggesting that BAG3 may have a role in the host response to LPS stimulation.

Phosphorylation of 4E-BP by LRRK2 affects the maintenance of dopaminergic neurons in Drosophila.

Dominant mutations in leucine-rich repeat kinase 2 (LRRK2) are the most frequent molecular lesions so far found in Parkinson's disease (PD), an age-dependent neurodegenerative disorder affecting dopaminergic (DA) neuron. The molecular mechanisms by which mutations in LRRK2 cause DA degeneration in PD are not understood. Here, we show that both human LRRK2 and the Drosophila orthologue of LRRK2 phosphorylate eukaryotic initiation factor 4E (eIF4E)-binding protein (4E-BP), a negative regulator of eIF4E-mediated protein translation and a key mediator of various stress responses. Although modulation of the eIF4E/4E-BP pathway by LRRK2 stimulates eIF4E-mediated protein translation both in vivo and in vitro, it attenuates resistance to oxidative stress and survival of DA neuron in Drosophila. Our results suggest that chronic inactivation of 4E-BP by LRRK2 with pathogenic mutations deregulates protein translation, eventually resulting in age-dependent loss of DA neurons.

Autophagy-independent enhancing effects of Beclin 1 on cytotoxicity of ovarian cancer cells mediated by proteasome inhibitors.

BACKGROUND: The ubiquitin-proteasome system and macroautophagy (hereafter referred to autophagy) are two complementary pathways for protein degradation. Emerging evidence suggests that proteasome inhibition might be a promising approach for tumor therapy. Accumulating data suggest that autophagy is activated as a compensatory mechanism upon proteasome activity is impaired. METHOD: Autophagy activation was measured using acridine orange staining and LC3 transition. Cell viability and apoptosis were measured using MTT assay and flow cytometry, respectively. Beclin 1 expression vectors or shRNA against Beclin 1 (shBeclin 1) were transfected to investigate the role of Beclin 1 in autophagy activation and cytotoxicity of ovarian cancer cells induced by proteasome inhibitors. RESULTS: Proteasome inhibitors suppressed proliferation and induced autophagy in ovarian cancer cells. Neither phosphoinositide 3-kinase (PI3K) inhibitors nor shRNA against Beclin 1 could abolish the formation of acidic vacuoles and the processing of LC3 induced by proteasome inhibitors. Moreover, Beclin 1 overexpression enhanced anti-proliferative effects of proteasome inhibitors in ovarian cancer cells. CONCLUSIONS: For the first time, the current study demonstrated that proteasome inhibitors induced PI3K and Beclin 1-independent autophagy in ovarian cancer cells. In addition, this study revealed autophagy-independent tumor suppressive effects of Beclin 1 in ovarian cancer cells.