bims-stacyt 2018-10-14 papers

Biochem Biophys Res Commun. 2018 Oct 03. pii: S0006-291X(18)32104-1. [Epub ahead of print]

MicroRNA-182-5p attenuates cerebral ischemia-reperfusion injury by targeting Toll-like receptor 4.

Ji Wang, Zhimin Xu, Xiufen Chen, Yan Li, Chen Chen, Chongwu Wang, Jianwei Zhu, Zhaotao Wang, Wenjin Chen, Zongyu Xiao, Ruxiang Xu.

Cerebral ischemia-reperfusion-induced microglial activation causes neuronal death through the release of inflammatory cytokines. Increasing evidence suggests that microRNAs (miRNAs) exert a neuroprotective effect by modulating the inflammatory process in cerebral ischemia-reperfusion injury. Furthermore, Toll-like receptor 4 (TLR4) is increasingly being considered to have a significant role in the regulation of inflammation. However, whether miRNAs mediate their neuroprotective effects by regulating TLR4-mediated inflammatory responses remains unknown. To explore this gap in the literature, we conducted both in vitro and in vivo experiments. In vitro: BV2 cells were activated by oxygen-glucose deprivation (OGD). TLR4 and inflammatory cytokine (TNF-a, IL-6, and IL-1β) transcription and translation expression levels were assessed using RT-PCR, ELISA, and western blot. BV2 cells were transfected with miR-182-5p mimics, inhibitors, siTLR4, or negative control (NC) using lipofectamine 2000 reagent. To confirm whether TLR4 is a direct target of miR-182-5p, we performed a luciferase reporter assay. In BV2 cells, we observed that OGD upregulated TLR4 expression, but downregulated miR-182-5p expression. We determined that miR-182-5p inhibited TLR4 by directly binding to its 3'-UTR. Furthermore, miR-182-5p suppressed the release of TNF-a, IL-6, and IL-1β. In vivo: A middle cerebral artery occlusion (MCAO) rat model was used to mimic cerebral ischemia-reperfusion. Iba1 and TLR4 double staining was used to demonstrate that the target of miR-182-5p in microglial cells, and the mediator of the anti-inflammatory effect, is TLR4. TTC staining was performed to evaluate the infarct volume. Compared to the animals treated with miR-182-5p NC and normal saline, rats treated with miR-182-5p mimics demonstrated significantly enhanced neurological functions. TTC staining results were consistent with neurological function test findings. In summary, our data suggested that miR-182-5p exhibits potential neuroprotective effects in the cerebral ischemia-reperfusion injury via the regulation of the TLR4-mediated inflammatory response.

Keywords: Cerebral ischemia reperfusion; Microglial; Toll-like receptor 4; miR-182-5p

DOI: https://doi.org/10.1016/j.bbrc.2018.09.165

Toxicol Lett. 2018 Oct 03. pii: S0378-4274(18)31963-5. [Epub ahead of print]

ASIC1a promotes high glucose and PDGF-induced hepatic stellate cell activation by inducing autophagy through CaMKKβ/ERK signaling pathway.

Yinghong Wang, Yancai Sun, Longquan Zuo, Yanan Wang, Yan Huang.

It is well known that the diabetes mellitus complicates liver fibrosis with high morbidity, and Acid-sensing ion Channel 1a (ASIC1a) plays an important role in the development of diabetes and liver fibrosis. However, the underlying mechanism about how diabetes influences the progression of liver fibrosis remains unclear. This study was to investigate the relationship between autophagy and ASIC1a in the process of liver fibrosis under hyperglycemia. Interestingly, our study showed that the autophagy was elevated in the livers from diabetes combined with liver fibrosis double model in vivo and also in rat hepatic stellate cell line HSC-T6 after stimulation with high glucose and platelet-derived growth factor (PDGF) in vitro, and this response could be attenuated by treatment with ASIC1a nonspecific inhibitor Amiloride or specific ShRNA for ASIC1a. Furthermore, inhibition of autophagy treated with 3-MA significantly attenuated HSC-T6 activation and proliferation. Mechanistically, CaMKKβ/ERK pathway was activated in HSC-T6 after stimulation with high glucose and PDGF, and could be suppressed by Amiloride. Collectively, we concluded that autophagy induced by ASIC1a contributes to HSC-T6 activation, which ing pathway.

Keywords: ASIC1a; HSCs; autophagy; hyperglycemia; liver fibrosis

DOI: https://doi.org/10.1016/j.toxlet.2018.10.003

Mol Cancer. 2018 Oct 06. 17(1): 146

Tumor-derived exosomes induce N2 polarization of neutrophils to promote gastric cancer cell migration.

Xu Zhang, Hui Shi, Xiao Yuan, Pengcheng Jiang, Hui Qian, Wenrong Xu.

BACKGROUND: Exosomes are extracellular vesicles that mediate cellular communication in health and diseases. Neutrophils could be polarized to a pro-tumor phenotype by tumor. The function of tumor-derived exosomes in neutrophil regulation remains unclear.
METHODS: We investigated the effects of gastric cancer cell-derived exosomes (GC-Ex) on the pro-tumor activation of neutrophils and elucidated the underlying mechanisms.
RESULTS: GC-Ex prolonged neutrophil survival and induced expression of inflammatory factors in neutrophils. GC-Ex-activated neutrophils, in turn, promoted gastric cancer cell migration. GC-Ex transported high mobility group box-1 (HMGB1) that activated NF-κB pathway through interaction with TLR4, resulting in an increased autophagic response in neutrophils. Blocking HMGB1/TLR4 interaction, NF-κB pathway, and autophagy reversed GC-Ex-induced neutrophil activation. Silencing HMGB1 in gastric cancer cells confirmed HMGB1 as a key factor for GC-Ex-mediated neutrophil activation. Furthermore, HMGB1 expression was upregulated in gastric cancer tissues. Increased HMGB1 expression was associated with poor prognosis in patients with gastric cancer. Finally, gastric cancer tissue-derived exosomes acted similarly as exosomes derived from gastric cancer cell lines in neutrophil activation.
CONCLUSION: We demonstrate that gastric cancer cell-derived exosomes induce autophagy and pro-tumor activation of neutrophils via HMGB1/TLR4/NF-κB signaling, which provides new insights into mechanisms for neutrophil regulation in cancer and sheds lights on the multifaceted role of exosomes in reshaping tumor microenvironment.

Keywords: Activation; Autophagy; Exosome; Gastric cancer; Neutrophil; Pro-tumor

DOI: https://doi.org/10.1186/s12943-018-0898-6

Neurochem Int. 2018 Oct 04. pii: S0197-0186(18)30435-2. [Epub ahead of print]

Tyrosol attenuates pro-inflammatory cytokines from cultured astrocytes and NF-κB activation in in vitro oxygen glucose deprivation.

Gang Luo, Yinuo Huang, Dapeng Mo, Ning Ma, Feng Gao, Ligang Song, Xuan Sun, Xiaotong Xu, Lian Liu, Xiaochuan Huo, Bo Wang, Xiaoqing Li, Baixue Jia, Yiming Deng, Xuelei Zhang, Alejandro Fernandez-Escobar, Guangge Peng, Zhongrong Miao.

Subsequent inflammation in stroke plays an important role in the damage of neurons in the perilesional area. Therapeutic intervention targeting inflammation may be a promising complementary strategy to current treatments of stroke. Here, we explored the possible beneficial effects of tyrosol, a derivative of phenethyl alcohol and natural antioxidant, playing an anti-inflammatory role in astrocyte culture and in vitro oxygen glucose deprivation (OGD) model. MTT, western blot, ELISA and EMSA assays were carried out to investigate cell viability, protein expression level, cytokine expression and NF-κB activity. We found tyrosol protected cultured astrocytes against OGD-induced cell viability loss in MTT test. Meanwhile, tyrosol attenuated the released TNF-α and IL-6 level from astrocyte via regulating Janus N-terminal kinase (JNK). The reduction of cytokines from astrocyte might be due to its inhibition of astrocyte activation and regulation of STAT3 signaling pathway since tyrosol attenuated the expression level of GFAP (glial fibrillary acidic protein) and the phosphorylation of STAT3. Additionally, we demonstrated that tyrosol prevented the degradation of IκBα and the increase of IκBα phosphorylation in astrocytes exposed to OGD, which led to the suppression of NF-κB function during ischemia. Collectively, our results showed that tyrosol may be a promising complementary treatment compound for stroke via modulating the inflammatory response in astrocytes during ischemia.

Keywords: Astrocyte; IL-6; Oxygen glucose deprivation; STAT3; TNF-α

DOI: https://doi.org/10.1016/j.neuint.2018.10.006

Med Sci Monit. 2018 Oct 07. 24 7152-7161

Toll-Like Receptor 4 (TLR-4) Pathway Promotes Pulmonary Inflammation in Chronic Intermittent Hypoxia-Induced Obstructive Sleep Apnea.

Jiao-Jiao Yang, Shu-Juan Wang, Xiaoling Gao, Bei Wang, Yan-Ting Dong, Yang Bai, Yan Chen, Jian-Nan Gong, Ya-Qiong Huang, Dong-Dong An.

BACKGROUND Studies have shown that intermittent hypoxia mimics obstructive sleep apnea in causing pulmonary inflammation, but the mechanism is not yet clear.TLR-4 is a recognized proinflammatory factor, so the purpose of this study was to assess the function of TLR-4 in pulmonary inflammation induced by chronic intermittent hypoxia simulating obstructive sleep apnea. MATERIAL AND METHODS Healthy male Wistar rats were divided into 3 groups (8 in each group): the normoxia control group (CG), the intermittent hypoxia group (IH), and the TLR4 antagonist TAK242 treatment group (3 mg/kg, daily), with exposure durations of 12 weeks and 16 weeks (HI). The morphological changes of lung tissue were determined with hematoxylin-eosin (HE) staining. The expressions of the TLR-4 pathway in lung tissue were tested by Western blotting and RT-PCR. The levels of IL-6 and TNF-a in serum and lung tissue were detected by enzyme-linked immunosorbent assay (ELISA). The levels of SOD and MDA in lung tissue were detected by use of SOD and MDA kits, respectively. RESULTS After TAK242 treatment, damage to lung tissue was increased, and the expressions of TLR-4, MYD88, P65, IL-6, TNF-α, MDA, and SOD were decreased. Intermittent hypoxic exposure caused alveolar expansion, thickening of alveolar septum, and fusion of adjacent alveoli into larger cysts under intermittent hypoxia in a time-dependent manner. Compared with the CG and HI groups, the mean lining interval (MLI) become more thickened and the alveolar destruction index (DI) increased significantly in the IH group. CONCLUSIONS Chronic intermittent hypoxia causes pulmonary inflammatory response and the inflammatory pathway involved in TLR4 receptor may be one of the mechanisms that trigger lung inflammation.

DOI: https://doi.org/10.12659/MSM.910632