The landscape of transcriptional profiles in human oocytes with different chromatin configurations.

With increasingly used assisted reproductive technology (ART), the acquisition of high-quality oocytes and early embryos has become the focus of much attention. Studies in mice have found that the transition of chromatin conformation from non-surrounded nucleolus (NSN) to surrounded nucleolus (SN) is essential for oocyte maturation and early embryo development, and similar chromatin transition also exists in human oocytes. In this study, we collected human NSN and SN oocytes and investigated their transcriptome. The analysis of differentially expressed genes showed that epigenetic functions, cyclin-dependent kinases and transposable elements may play important roles in chromatin transition during human oocyte maturation. Our findings provide new insights into the molecular mechanism of NSN-to-SN transition of human oocyte and obtained new clues for improvement of oocyte in vitro maturation technique.

Enhancing clinical utility: deep learning-based embryo scoring model for non-invasive aneuploidy prediction.

BACKGROUND: The best method for selecting embryos ploidy is preimplantation genetic testing for aneuploidies (PGT-A). However, it takes more labour, money, and experience. As such, more approachable, non- invasive techniques were still needed. Analyses driven by artificial intelligence have been presented recently to automate and objectify picture assessments. METHODS: In present retrospective study, a total of 3448 biopsied blastocysts from 979 Time-lapse (TL)-PGT cycles were retrospectively analyzed. The "intelligent data analysis (iDA) Score" as a deep learning algorithm was used in TL incubators and assigned each blastocyst with a score between 1.0 and 9.9. RESULTS: Significant differences were observed in iDAScore among blastocysts with different ploidy. Additionally, multivariate logistic regression analysis showed that higher scores were significantly correlated with euploidy (p < 0.001). The Area Under the Curve (AUC) of iDAScore alone for predicting euploidy embryo is 0.612, but rose to 0.688 by adding clinical and embryonic characteristics. CONCLUSIONS: This study provided additional information to strengthen the clinical applicability of iDAScore. This may provide a non-invasive and inexpensive alternative for patients who have no available blastocyst for biopsy or who are economically disadvantaged. However, the accuracy of embryo ploidy is still dependent on the results of next-generation sequencing technology (NGS) analysis.

Signaling pathways in macrophages: molecular mechanisms and therapeutic targets.

Macrophages play diverse roles in development, homeostasis, and immunity. Accordingly, the dysfunction of macrophages is involved in the occurrence and progression of various diseases, such as coronavirus disease 2019 and atherosclerosis. The protective or pathogenic effect that macrophages exert in different conditions largely depends on their functional plasticity, which is regulated via signal transduction such as Janus kinase-signal transducer and activator of transcription, Wnt and Notch pathways, stimulated by environmental cues. Over the past few decades, the molecular mechanisms of signaling pathways in macrophages have been gradually elucidated, providing more alternative therapeutic targets for diseases treatment. Here, we provide an overview of the basic physiology of macrophages and expound the regulatory pathways within them. We also address the crucial role macrophages play in the pathogenesis of diseases, including autoimmune, neurodegenerative, metabolic, infectious diseases, and cancer, with a focus on advances in macrophage-targeted strategies exploring modulation of components and regulators of signaling pathways. Last, we discuss the challenges and possible solutions of macrophage-targeted therapy in clinical applications. We hope that this comprehensive review will provide directions for further research on therapeutic strategies targeting macrophage signaling pathways, which are promising to improve the efficacy of disease treatment.

Virtual Screening of Nrf2 Dietary-Derived Agonists and Safety by a New Deep-Learning Model and Verified In Vitro and In Vivo.

Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is an essential regulatory target of antioxidants, but the lack of Nrf2 active site information has hindered discovery of new Nrf2 agonists from food-derived compounds by large-scale virtual screening. Two deep-learning models were separately trained to screen for Nrf2-agonists and safety. The trained models screened potentially active chemicals from approximately 70,000 dietary compounds within 5 min. Of the 169 potential Nrf2 agonists identified via deep-learning screening, 137 had not been reported before. Six compounds selected from the new Nrf2 agonists significantly increased (p < 0.05) the activity of Nrf2 on carbon tetrachloride (CCl4)-intoxicated HepG2 cells (nicotiflorin (99.44 ± 18.5%), artemetin (97.91 ± 8.22%), daidzin (87.73 ± 3.77%), linonin (74.27 ± 5.73%), sinensetin (72.74 ± 10.41%), and tectoridin (77.78 ± 4.80%)), and their safety were demonstrated by an MTT assay. The safety and Nrf2 agonistic activity of nicotiflorin, artemetin, and daidzin were also reconfirm by a single-dose acute oral toxicity study and CCl4-intoxicated rat assay.

Multiple omics study identifies an interspecies conserved driver for nonalcoholic steatohepatitis.

Lipotoxicity is a recognized pathological trigger and accelerator of nonalcoholic steatohepatitis (NASH). However, the molecular basis of lipotoxicity-induced NASH remains elusive. Here, we systematically mapped the changes in hepatic transcriptomic landscapes in response to lipotoxic insults across multiple species. Conserved and robust activation of the arachidonic acid pathway, in particular the arachidonate 12-lipoxygenase (ALOX12) gene, was closely correlated with NASH severity in humans, macaques with spontaneously developed NASH, as well as swine and mouse dietary NASH models. Using gain- and loss-of-function studies, we found that ALOX12 markedly exacerbated NASH in both mice and Bama pig models. ALOX12 was shown to induce NASH by directly targeting acetyl-CoA carboxylase 1 (ACC1) via a lysosomal degradation mechanism. Overall, our findings reveal a key molecular driver of NASH pathogenesis and suggest that ALOX12-ACC1 interaction may be a therapeutic target in NASH.

A small molecule targeting ALOX12-ACC1 ameliorates nonalcoholic steatohepatitis in mice and macaques.

Nonalcoholic steatohepatitis (NASH) is a progressive liver disease and has become a leading indication for liver transplantation in the United States. The development of effective therapies for NASH is a major unmet need. Here, we identified a small molecule, IMA-1, that can treat NASH by interrupting the arachidonate 12-lipoxygenase (ALOX12)­acetyl-CoA carboxylase 1 (ACC1) interaction. IMA-1 markedly blocked diet-induced NASH progression in both male mice and Cynomolgus macaque therapeutic models. The anti-NASH efficacy of IMA-1 was comparable to ACC inhibitor in both species. Protein docking simulations and following functional experiments suggested that the anti-NASH effects of IMA-1 were largely dependent on its direct binding to a pocket in ALOX12 proximal to its ACC1-interacting surface instead of inhibiting ALOX12 lipoxygenase activity. IMA-1 treatment did not elicit hyperlipidemia, a known side effect of direct inhibition of ACC enzymatic activity, in both mice and macaques. These findings provide proof of concept across multiple species for the use of small molecule­based therapies for NASH.

SIMPLE Is an Endosomal Regulator That Protects Against NAFLD by Targeting the Lysosomal Degradation of EGFR.

BACKGROUND AND AIMS: NAFLD has become a tremendous burden for public health; however, there is no drug for NAFLD therapy at present. Impaired endo-lysosome-mediated protein degradation is observed in a variety of metabolic disorders, such as atherosclerosis, type 2 diabetes mellitus, and NAFLD. Small integral membrane protein of lysosome/late endosome (SIMPLE) is a regulator of endosome-to-lysosome trafficking and cell signaling, but the role that SIMPLE plays in NAFLD progression remains unknown. Here we investigated SIMPLE function in NAFLD development and sophisticated mechanism therein. APPROACH AND RESULTS: This study found that in vitro knockdown of SIMPLE significantly aggravated lipid accumulation and inflammation in hepatocytes treated with metabolic stimulation. Consistently, in vivo experiments showed that liver-specific Simple-knockout (Simple-HKO) mice exhibited more severe high-fat diet (HFD)-induced, high-fat-high-cholesterol diet (HFHC)-induced, and methionine-choline-deficient diet (MCD)-induced steatosis, glucose intolerance, inflammation, and fibrosis than those fed with normal chow (NC) diet. Meanwhile, RNA-sequencing demonstrated the up-regulated signaling pathways and signature genes involved in lipid metabolism, inflammation, and fibrosis in Simple-HKO mice compared with control mice under metabolic stress. Mechanically, we found SIMPLE directly interact with epidermal growth factor receptor (EGFR). SIMPLE deficiency results in dysregulated degradation of EGFR, subsequently hyperactivated EGFR phosphorylation, thus exaggerating NAFLD development. Moreover, we demonstrated that using EGFR inhibitor or silencing EGFR expression could ameliorate lipid accumulation induced by the knockdown of SIMPLE. CONCLUSIONS: SIMPLE ameliorated NASH by prompting EGFR degradation and can be a potential therapeutic candidate for NASH.

TMBIM1 is an inhibitor of adipogenesis and its depletion promotes adipocyte hyperplasia and improves obesity-related metabolic disease.

Obesity is characterized by the excessive accumulation of the white adipose tissue (WAT), but healthy expansion of WAT via adipocyte hyperplasia can offset the negative metabolic effects of obesity. Thus, identification of novel adipogenesis regulators that promote hyperplasia may lead to effective therapies for obesity-induced metabolic disorders. Using transcriptomic approaches, we identified transmembrane BAX inhibitor motif-containing 1 (TMBIM1) as an inhibitor of adipogenesis. Gain or loss of function of TMBIM1 in preadipocytes inhibited or promoted adipogenesis, respectively. In vivo, in response to caloric excess, adipocyte precursor (AP)-specific Tmbim1 knockout (KO) mice displayed WAT hyperplasia and improved systemic metabolic health, while overexpression of Tmbim1 in transgenic mice showed the opposite effects. Moreover, mature adipocyte-specific Tmbim1 KO did not affect WAT cellularity or nutrient homeostasis. Mechanistically, TMBIM1 binds to and promotes the autoubiquitination and degradation of NEDD4, which is an E3 ligase that stabilizes PPARγ. Our data show that TMBIM1 is a potent repressor of adipogenesis and a potential therapeutic target for obesity-related metabolic disease.

The Neutrophil-to-Lymphocyte Ratio Determines Clinical Efficacy of Corticosteroid Therapy in Patients with COVID-19.

Corticosteroid therapy is now recommended as a treatment in patients with severe COVID-19. But one key question is how to objectively identify severely ill patients who may benefit from such therapy. Here, we assigned 12,862 COVID-19 cases from 21 hospitals in Hubei Province equally to a training and a validation cohort. We found that a neutrophil-to-lymphocyte ratio (NLR) > 6.11 at admission discriminated a higher risk for mortality. Importantly, however, corticosteroid treatment in such individuals was associated with a lower risk of 60-day all-cause mortality. Conversely, in individuals with an NLR ≤ 6.11 or with type 2 diabetes, corticosteroid treatment was not associated with reduced mortality, but rather increased risks of hyperglycemia and infections. These results show that in the studied cohort corticosteroid treatment is associated with beneficial outcomes in a subset of COVID-19 patients who are non-diabetic and with severe symptoms as defined by NLR.

In-Hospital Use of Statins Is Associated with a Reduced Risk of Mortality among Individuals with COVID-19.

Statins are lipid-lowering therapeutics with favorable anti-inflammatory profiles and have been proposed as an adjunct therapy for COVID-19. However, statins may increase the risk of SARS-CoV-2 viral entry by inducing ACE2 expression. Here, we performed a retrospective study on 13,981 patients with COVID-19 in Hubei Province, China, among which 1,219 received statins. Based on a mixed-effect Cox model after propensity score-matching, we found that the risk for 28-day all-cause mortality was 5.2% and 9.4% in the matched statin and non-statin groups, respectively, with an adjusted hazard ratio of 0.58. The statin use-associated lower risk of mortality was also observed in the Cox time-varying model and marginal structural model analysis. These results give support for the completion of ongoing prospective studies and randomized controlled trials involving statin treatment for COVID-19, which are needed to further validate the utility of this class of drugs to combat the mortality of this pandemic.

Targeting Transmembrane BAX Inhibitor Motif Containing 1 Alleviates Pathological Cardiac Hypertrophy.

BACKGROUND: Cardiac hypertrophy and its resultant heart failure are among the most common causes of mortality worldwide. Abnormal protein degradation, especially the impaired lysosomal degradation of large organelles and membrane proteins, is involved in the progression of cardiac hypertrophy. However, the underlying mechanisms have not been fully elucidated. METHODS: We investigated cardiac transmembrane BAX inhibitor motif containing 1 (TMBIM1) mRNA and protein expression levels in samples from patients with heart failure and mice with aortic banding (AB)-induced cardiac hypertrophy. We generated cardiac-specific Tmbim1 knockout mice and cardiac-specific Tmbim1-overexpressing transgenic mice and then challenged them with AB surgery. We used microarray, confocal image, and coimmunoprecipitation analyses to identify the downstream targets of TMBIM1 in cardiac hypertrophy. Tmbim1/Tlr4 double-knockout mice were generated to investigate whether the effects of TMBIM1 on cardiac hypertrophy were Toll-like receptor 4 (TLR4) dependent. Finally, lentivirus-mediated TMBIM1 overexpression in a monkey AB model was performed to evaluate the therapeutic potential of TMBIM1. RESULTS: TMBIM1 expression was significantly downregulated on hypertrophic stimuli in both human and mice heart samples. Silencing cardiac Tmbim1 aggravated AB-induced cardiac hypertrophy. This effect was blunted by Tmbim1 overexpression. Transcriptome profiling revealed that the TLR4 signaling pathway was disrupted dramatically by manipulation of Tmbim1. The effects of TMBIM1 on cardiac hypertrophy were shown to be dependent on TLR4 in double-knockout mice. Fluorescent staining indicated that TMBIM1 promoted the lysosome-mediated degradation of activated TLR4. Coimmunoprecipitation assays confirmed that TMBIM1 directly interacted with tumor susceptibility gene 101 via a PTAP motif and accelerated the formation of multivesicular bodies that delivered TLR4 to the lysosomes. Finally, lentivirus-mediated TMBIM1 overexpression reversed AB-induced cardiac hypertrophy in monkeys. CONCLUSIONS: TMBIM1 protects against pathological cardiac hypertrophy through promoting the lysosomal degradation of activated TLR4. Our findings reveal the central role of TMBIM1 as a multivesicular body regulator in the progression of pathological cardiac hypertrophy, as well as the role of vesicle trafficking in signaling regulation during cardiac hypertrophy. Moreover, targeting TMBIM1 could be a novel therapeutic strategy for treating cardiac hypertrophy and heart failure.

Tmbim1 is a multivesicular body regulator that protects against non-alcoholic fatty liver disease in mice and monkeys by targeting the lysosomal degradation of Tlr4.

Non-alcoholic steatohepatitis (NASH) is an increasingly prevalent liver pathology that can progress from non-alcoholic fatty liver disease (NAFLD), and it is a leading cause of cirrhosis and hepatocellular carcinoma. There is currently no pharmacological therapy for NASH. Defective lysosome-mediated protein degradation is a key process that underlies steatohepatitis and a well-recognized drug target in a variety of diseases; however, whether it can serve as a therapeutic target for NAFLD and NASH remains unknown. Here we report that transmembrane BAX inhibitor motif-containing 1 (TMBIM1) is an effective suppressor of steatohepatitis and a previously unknown regulator of the multivesicular body (MVB)-lysosomal pathway. Tmbim1 expression in hepatocytes substantially inhibited high-fat diet-induced insulin resistance, hepatic steatosis and inflammation in mice. Mechanistically, Tmbim1 promoted the lysosomal degradation of toll-like receptor 4 by cooperating with the ESCRT endosomal sorting complex to facilitate MVB formation, and the ubiquitination of Tmbim1 by the E3 ubiquitin ligase Nedd4l was required for this process. We also found that overexpression of Tmbim1 in the liver effectively inhibited a severe form of NAFLD in mice and NASH progression in monkeys. Taken together, these findings could lead to the development of promising strategies to treat NASH by targeting MVB regulators to properly orchestrate the lysosome-mediated protein degradation of key mediators of the disease.

Cardiac-Specific EPI64C Blunts Pressure Overload-Induced Cardiac Hypertrophy.

The calcium-responsive molecule, calcineurin, has been well characterized to play a causal role in pathological cardiac hypertrophy over the past decade. However, the intrinsic negative regulation of calcineurin signaling during the progression of cardiomyocyte hypertrophy remains enigmatic. Herein, we explored the role of EPI64C, a dual inhibitor of both Ras and calcineurin signaling during T-cell activation, in pressure overload-induced cardiac hypertrophy. We generated a cardiac-specific Epi64c conditional knockout mouse strain and showed that loss of Epi64c remarkably exacerbates pressure overload-induced cardiac hypertrophy. In contrast, EPI64C gain-of-function in cardiomyocyte-specific Epi64c transgenic mice exerts potent protective effects against cardiac hypertrophy. Mechanistically, the cardioprotective effects of EPI64C are largely attributed to the disrupted calcineurin signaling but are independent of its Ras suppressive capability. Molecular studies have indicated that the 406 to 446 C-terminal amino acids in EPI64C directly bind to the 287 to 337 amino acids in the catalytic domain of calcineurin, which is responsible for the EPI64C-mediated suppressive effects. We further extrapolated our studies to cynomolgus monkeys and showed that gene therapy based on lentivirus-mediated EPI64C overexpression in the monkey hearts blunted pressure overload-induced cardiac hypertrophy. Our study thus identified EPI64C as a novel negative regulator in cardiac hypertrophy by targeting calcineurin signaling and demonstrated the potential of gene therapy and drug development for treating cardiac hypertrophy.

DKK3 expression in hepatocytes defines susceptibility to liver steatosis and obesity.

BACKGROUND & AIMS: Dickkopf-3 (DKK3), a protein belonging to the DKK family, has been extensively investigated in the context of cancer, including liver cancer. However, the role of DKK3 in hepatic steatosis and related metabolic disorders remains largely unexplored. METHODS: We detected the expression of DKK3 in the fatty livers of NAFLD patients and of obese mice and investigated the function of DKK3 in hepatic steatosis and related metabolic disorders by using hepatocyte-specific DKK3 deficiency or overexpression obese mice induced by high fat diet (HFD) or genetic defect (ob/ob). The molecular mechanisms underlying DKK3-regulated hepatic steatosis were further explored and verified in mice. RESULTS: DKK3 expression was significantly decreased in the livers of NAFLD patients and of obese mice as well as in cultured hepatocytes stimulated with palmitate. Further investigation indicated that specific overexpression of DKK3 in hepatocytes enhanced insulin sensitivity and glucose tolerance, reduced the inflammatory response, and ameliorated the imbalance of lipid metabolism in response to HFD or genetic defects. In contrast, DKK3 deficiency in hepatocytes led to an almost complete reversal of these pathologies. Mechanistically, DKK3 combined with Apoptosis signal-regulating kinase 1 (ASK1) under palmitate stimulation, and thus inhibited the activation of the downstream P38/JNK pathway. Importantly, dominant-negative ASK1 blocked the accelerated effects of DKK3 deficiency, while the constitutively active form of ASK1 overcame the inhibitory effects of DKK3 overexpression on HFD-induced metabolic disorders in vivo. CONCLUSION: DKK3 functions as a negative regulator of insulin resistance, hepatic steatosis, and associated inflammatory responses, which depends on its inhibitory regulation of ASK1 activity. LAY SUMMARY: DKK3 expression is decreased in the non-alcoholic fatty liver of humans and mice. Adding DKK3 expression alleviates fatty liver in mice by inhibiting ASK1 activity.

Hepatocyte TRAF3 promotes liver steatosis and systemic insulin resistance through targeting TAK1-dependent signalling.

Non-alcoholic fatty liver disease (NAFLD) is characterized by hepatic steatosis, insulin resistance and a systemic pro-inflammatory response. Here we show that tumour necrosis factor receptor-associated factor 3 (TRAF3) is upregulated in mouse and human livers with hepatic steatosis. After 24 weeks on a high-fat diet (HFD), obesity, insulin resistance, hepatic steatosis and inflammatory responses are significantly ameliorated in liver-specific TRAF3-knockout mice, but exacerbated in transgenic mice overexpressing TRAF3 in hepatocytes. The detrimental effects of TRAF3 on hepatic steatosis and related pathologies are confirmed in ob/ob mice. We further show that in response to HFD, hepatocyte TRAF3 binds to TGF-ß-activated kinase 1 (TAK1) to induce TAK1 ubiquitination and subsequent autophosphorylation, thereby enhancing the activation of downstream IKKß-NF-κB and MKK-JNK-IRS1(307) signalling cascades, while disrupting AKT-GSK3ß/FOXO1 signalling. The TRAF3-TAK1 interaction and TAK1 ubiquitination are indispensable for TRAF3-regulated hepatic steatosis. In conclusion, hepatocyte TRAF3 promotes HFD-induced or genetic hepatic steatosis in a TAK1-dependent manner.

Targeting TRAF3 signaling protects against hepatic ischemia/reperfusions injury.

BACKGROUND & AIMS: The hallmarks of hepatic ischemia/reperfusion (I/R) injury, a common clinical problem that occurs during liver surgical procedures, include severe cell death and inflammatory responses that contribute to early graft failure and a higher incidence of organ rejection. Unfortunately, effective therapeutic strategies are limited. Tumor necrosis factor receptor (TNFR)-associated factor (TRAF) 3 transduces apoptosis and/or inflammation-related signaling pathways to regulate cell survival and cytokine production. However, the role of TRAF3 in hepatic I/R-induced liver damage remains unknown. METHODS: Hepatocyte- or myeloid cell-specific TRAF3 knockdown or transgenic mice were subjected to an I/R model in vivo, and in vitro experiments were performed by treating primary hepatocytes from these mice with hypoxia/reoxygenation stimulation. The function of TRAF3 in I/R-induced liver damage and the potential underlying mechanisms were investigated through various phenotypic analyses and biological approaches. RESULTS: Hepatocyte-specific, but not myeloid cell-specific, TRAF3 deficiency reduced cell death, inflammatory cell infiltration, and cytokine production in both in vivo and in vitro hepatic I/R models, whereas hepatic TRAF3 overexpression resulted in the opposite effects. Mechanistically, TRAF3 directly binds to TAK1, which enhances the activation of the downstream NF-κB and JNK pathways. Importantly, inhibition of TAK1 almost completely reversed the TRAF3 overexpression-mediated exacerbation of I/R injury. CONCLUSIONS: TRAF3 is a novel hepatic I/R mediator that promotes liver damage and inflammation via TAK1-dependent activation of the JNK and NF-κB pathways. Inhibition of hepatic TRAF3 may represent a promising approach to protect the liver against I/R injury-related diseases.

The long noncoding RNA Gm15055 represses Hoxa gene expression by recruiting PRC2 to the gene cluster.

The Hox genes encode transcription factors that determine embryonic pattern formation. In embryonic stem cells, the Hox genes are silenced by PRC2. Recent studies have reported a role for long noncoding RNAs in PRC2 recruitment in vertebrates. However, little is known about how PRC2 is recruited to the Hox genes in ESCs. Here, we used stable knockdown and knockout strategies to characterize the function of the long noncoding RNAGm15055 in the regulation of Hoxa genes in mouse ESCs. We found that Gm15055 is highly expressed in mESCs and its expression is maintained by OCT4.Gm15055 represses Hoxa gene expression by recruiting PRC2 to the cluster and maintaining the H3K27me3 modification on Hoxa promoters. A chromosome conformation capture assay revealed the close physical association of the Gm15055 locus to multiple sites at the Hoxa gene cluster in mESCs, which may facilitate the in cis targeting of Gm15055RNA to the Hoxa genes. Furthermore, an OCT4-responsive positive cis-regulatory element is found in the Gm15055 gene locus, which potentially regulates both Gm15055 itself and the Hoxa gene activation. This study suggests how PRC2 is recruited to the Hoxa locus in mESCs, and implies an elaborate mechanism for Hoxa gene regulation in mESCs.

Neuron-Specific Tumor Necrosis Factor Receptor-Associated Factor 3 Is a Central Regulator of Neuronal Death in Acute Ischemic Stroke.

Neuronal death after ischemic stroke involves multiple pathophysiological events, as well as a complex molecular mechanism. Inhibiting a single therapeutic target that is involved in several ischemic signaling cascades may be a promising strategy for stroke management. Here, we report the versatile biological roles of tumor necrosis factor receptor-associated factor 3 (TRAF3) in ischemic stroke. Using several genetically manipulated mouse strains, we also demonstrated that TRAF3 inhibition can be neuroprotective. TRAF3 expression, which is robustly induced in response to ischemia/reperfusion (I/R) injury, was detected in neurons. Overexpression of TRAF3 in neurons led to aggravated neuronal loss and enlarged infarcts; these effects were reversed in TRAF3-knockout mice. Neuronal TRAF3 also contributed to c-Jun kinase-, nuclear factor κB- and Rac-1-induced neuronal death, inflammation, and oxidative stress. Mechanistically, we showed that TRAF3 interacts with transforming growth factor-ß-activated kinase 1 (TAK1) and potentiates phosphorylation and activation of TAK1. Phosphorylated TAK1 sequentially initiated activation of nuclear factor κB, Rac-1/NADPH oxidase, and c-Jun kinase/c-Jun signaling cascades. Using a combination of adenoviruses encoding dominant-negative TAK1 and the TAK1 inhibitor 5Z-7-oxozeaenol, we demonstrated that the TRAF3-mediated activation of ischemic cascades was TAK1-dependent. More importantly, the adverse phenotypes observed in TRAF3-overexpressing mice were completely reversed when the TRAF3-TAK1 interaction was prevented. Therefore, we have shown that TRAF3 is a central regulator of ischemic pathways, including nuclear factor κB, Rac-1, and c-Jun kinase signaling, via its interaction with and activation of TAK1. Furthermore, certain components of the TRAF3-TAK1 signaling pathway are potentially promising therapeutic targets in ischemic stroke.

Oncostatin M Confers Neuroprotection against Ischemic Stroke.

Cell-surface receptors provide potential targets for the translation of bench-side findings into therapeutic strategies; however, this approach for the treatment of stroke is disappointing, at least partially due to an incomplete understanding of the targeted factors. Previous studies of oncostatin M (OSM), a member of the gp130 cytokine family, have been limited, as mouse models alone may not strongly resemble the human condition enough. In addition, the precise function of OSM in the CNS remains unclear. Here, we report that human OSM is neuroprotective in vivo and in vitro by recruiting OSMRß in the setting of ischemic stroke. Using gain- and loss-of-function approaches, we demonstrated that decreased neuronal OSMRß expression results in deteriorated stroke outcomes but that OSMRß overexpression in neurons is cerebroprotective. Moreover, administering recombinant human OSM to mice before the onset of I/R showed that human OSM can be protective in rodent models of ischemic stroke. Mechanistically, OSM/OSMRß activate the JAK2/STAT3 prosurvival signaling pathway. Collectively, these data support that human OSM may represent a promising drug candidate for stroke treatment. SIGNIFICANCE STATEMENT: OSM, a member of the gp130 cytokine family, regulates neuronal function and survival. OSM engages a second receptor, either LIFRα or OSMRß, before recruiting gp130. However, it is not clear whether OSM/OSMRß signaling is involved in neuroprotection in the setting of ischemic stroke. Recent studies show that, compared with mouse disease models, the OSM receptor system in rats more closely resembles that in humans. In the present study, we use genetic manipulations of OSMRß in both mouse and rat stroke models to demonstrate that OSMRß in neurons is critical for neuronal survival during cerebral ischemic/reperfusion. Interestingly, administration of human OSM also leads to improved stroke outcomes. Therefore, OSM may represent a promising drug candidate for stroke treatment.