Qin Lu1,2, Rui Liu3,4,2, Prativa Sherchan2, Reng Ren2, Wei He2,5, Yuanjian Fang3,2, Yi Huang3,2, Hui Shi2,6, Lihui Tang3,2, Shuxu Yang1, John H Zhang2,7,8, Jiping Tang2. 1. Department of Neurosurgery, Sir Run Run Shaw Hospital (Q.L., S.Y.), School of Medicine, Zhejiang University, Hangzhou, China. 2. Department of Physiology and Pharmacology (Q.L., R.L., P.S., R.R., W.H., Y.F., Y.H., H.S., L.T., J.H.Z., J.T.), Loma Linda University, CA. 3. Department of Neurosurgery, The Second Affiliated Hospital (R.R., Y.F., Y.H., L.T.), School of Medicine, Zhejiang University, Hangzhou, China. 4. Department of Neurology, Guizhou Provincial People's Hospital, Guiyang, China (R.L.). 5. Department of Pharmacy, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China (W.H.). 6. Department of Neurosurgery, Yongchuan Hospital, Chongqing Medical University, China (H.S.). 7. Department of Neurosurgery (J.H.Z.), Loma Linda University, CA. 8. Department of Anesthesiology (J.H.Z.), Loma Linda University, CA.
Abstract
Background and Purpose: Intracerebral hemorrhage (ICH) is a devastating subtype of stroke with high mortality and disability. Inflammatory response promotes secondary brain injury after ICH. TREM (triggering receptor expressed on myeloid cells)-1 is a key regulator of inflammation. The aim of this study was to evaluate the role of TREM-1 in neuroinflammatory response after ICH in mice. Methods: CD1 mice (n=275) were used in this study. Mice were subjected to ICH by autologous blood injection. TREM-1 knockout CRISPR was administered intracerebroventricularly to evaluate the role of TREM-1 after ICH. A selective TREM-1 inhibitor, LP17, was administered intranasally 2 hours after ICH. To elucidate TREM-1 signaling pathway, CARD9 (caspase recruitment domain family member 9) activation CRISPR was administered with LP17 and TREM-1 activating anti-mouse TREM-1 monoclonal antibody (mAb) was administered with Rottlerin, a specific PKC (protein kinase C) δ inhibitor. Lastly, to evaluate the role of HMGB1 (high-mobility group box 1) in TREM-1 mediated microglia activation, glycyrrhizin, an inhibitor of HMBG1 was administered with TREM-1 activating mAb. Neurobehavioral test, brain water content, Western blot, immunofluorescence staining, and coimmunoprecipitation was performed. Results: TREM-1 knockout reduced ICH-induced neurobehavioral deficits and neuroinflammatory response. The temporal expression of HMGB1, TREM-1, PKC δ, and CARD9 increased after ICH. TREM-1 was expressed on microglia. Intranasal administration of LP17 significantly decreased brain edema and improved neurobehavioral outcomes at 24 and 72 hours after ICH. LP17 promoted M2 microglia polarization and reduced proinflammatory cytokines after ICH, which was reversed with CARD9 activation CRISPR. TREM-1 mAb increased neurobehavior deficits, proinflammatory cytokines, and reduced M2 microglia after ICH, which was reversed with Rottlerin. HMBG1 interaction with TREM-1 increased after ICH, and glycyrrhizin reduced neuroinflammation and promoted M2 microglia which was reversed with TREM-1 mAb. Conclusions: This study demonstrated that TREM-1 enhanced neuroinflammation by modulating microglia polarization after ICH, and this regulation was partly mediated via PKC δ/CARD9 signaling pathway and increased HMGB1 activation of TREM-1.
Background and Purpose: Intracerebral hemorrhage (ICH) is a devastating subtype of stroke with high mortality and disability. Inflammatory response promotes secondary brain injury after ICH. TREM (triggering receptor expressed on myeloid cells)-1 is a key regulator of inflammation. The aim of this study was to evaluate the role of TREM-1 in neuroinflammatory response after ICH in mice. Methods: CD1 mice (n=275) were used in this study. Mice were subjected to ICH by autologous blood injection. TREM-1 knockout CRISPR was administered intracerebroventricularly to evaluate the role of TREM-1 after ICH. A selective TREM-1 inhibitor, LP17, was administered intranasally 2 hours after ICH. To elucidate TREM-1 signaling pathway, CARD9 (caspase recruitment domain family member 9) activation CRISPR was administered with LP17 and TREM-1 activating anti-mouse TREM-1 monoclonal antibody (mAb) was administered with Rottlerin, a specific PKC (protein kinase C) δ inhibitor. Lastly, to evaluate the role of HMGB1 (high-mobility group box 1) in TREM-1 mediated microglia activation, glycyrrhizin, an inhibitor of HMBG1 was administered with TREM-1 activating mAb. Neurobehavioral test, brain water content, Western blot, immunofluorescence staining, and coimmunoprecipitation was performed. Results: TREM-1 knockout reduced ICH-induced neurobehavioral deficits and neuroinflammatory response. The temporal expression of HMGB1, TREM-1, PKC δ, and CARD9 increased after ICH. TREM-1 was expressed on microglia. Intranasal administration of LP17 significantly decreased brain edema and improved neurobehavioral outcomes at 24 and 72 hours after ICH. LP17 promoted M2 microglia polarization and reduced proinflammatory cytokines after ICH, which was reversed with CARD9 activation CRISPR. TREM-1 mAb increased neurobehavior deficits, proinflammatory cytokines, and reduced M2 microglia after ICH, which was reversed with Rottlerin. HMBG1 interaction with TREM-1 increased after ICH, and glycyrrhizin reduced neuroinflammation and promoted M2 microglia which was reversed with TREM-1 mAb. Conclusions: This study demonstrated that TREM-1 enhanced neuroinflammation by modulating microglia polarization after ICH, and this regulation was partly mediated via PKC δ/CARD9 signaling pathway and increased HMGB1 activation of TREM-1.
Authors: Manuel Navarro-Oviedo; Carmen Roncal; Agustina Salicio; Miriam Belzunce; Obdulia Rabal; Estefanía Toledo; Beatriz Zandio; Jose A Rodríguez; Jose A Páramo; Roberto Muñoz; Josune Orbe Journal: Transl Stroke Res Date: 2018-07-27 Impact factor: 6.829
Authors: Michal A Rynkowski; Grace H Kim; Ricardo J Komotar; Marc L Otten; Andrew F Ducruet; Brad E Zacharia; Christopher P Kellner; David K Hahn; Maxwell B Merkow; Matthew C Garrett; Robert M Starke; Byung-Moon Cho; Sergei A Sosunov; E Sander Connolly Journal: Nat Protoc Date: 2008 Impact factor: 13.491
Authors: Jun Yan; Gang Zuo; Prativa Sherchan; Lei Huang; Umut Ocak; Weilin Xu; Zachary D Travis; Wenna Wang; John H Zhang; Jiping Tang Journal: Neurotherapeutics Date: 2020-07 Impact factor: 6.088