Stroke STR A Novel Approach to Visualize Microglia Death and Proliferation after Intracerebral Hemorrhage in Mice Microglia death and proliferation after ICH STROKE/2022/040302 STROKE/2022/040302 10.1161/STROKEAHA.122.040302 53 11/01/22 11 Conflict of interest statement: Cain Erinn 7819024395 Aronowski, Jaroslaw University of Texas-Houston Dr. Guohua Xi guohuaxi@umich.edu Dr. University of Michigan R5018 Biomedical Science Research Building Ann Arbor Michigan 48109-2200 UNITED STATES 1-734-764-1207 43990 0000-0003-2846-5937 fenghui ye The University of Michigan fenghuiy@umich.edu 735257 Jinting Yang University of Michigan yjinting@umich.edu 764850 0000-0002-9805-8248 Ya Hua University of Michigan yahua@umich.edu 44740 0000-0003-0100-2289 Richard F. Keep University of Michigan rkeep@umich.edu 43742 0000-0001-6441-5334 Guohua Xi University of Michigan guohuaxi@umich.edu 43990 0000-0003-2846-5937 06/08/2022 06/08/2022 08/18/2022 08/30/2022 09/07/2022 10/24/2022 Brief Report Basic & Transitional Sciences Background and Purpose: Microglia are important brain immune cells. However, it is difficult to differentiate microglia from monocyte-derived macrophages. To visualize microglia changes following intracerebral hemorrhage (ICH), we utilized a genetic knock-in mouse line, Tmem119-enhanced green fluorescent protein (EGFP), which expresses EGFP specifically in microglia. Methods: There were two parts in this study. First, autologous blood was injected into the right basal ganglia to model ICH in Tmem119-EGFP mice. Mice were euthanized at 4 hours, days 1, 3, and 7 after ICH. Sham animals were used as controls. Second, Tmem119-EGFP mice were injected with iron or thrombin, factors involved in ICH-induced injury, and were euthanized at 4 hours. Naïve mice were controls. Brains were harvested for histology. Results: The number of perihematomal microglia significantly decreased 1 day after ICH, but markedly increased by days 3 and 7. Microglia death was also induced by intracerebral iron injection while microglia proliferation was found with intracerebral thrombin injection. Conclusions: Perihematomal microglia death and proliferation after ICH are visualized in vivo with a Tmem119-EGFP transgenic mouse line. Iron and thrombin may contribute to ICH-induced microglia death and proliferation, respectively. 2037 0 0 0 3 3 no yes STR_STROKE-2022-040302_merge.pdf STR_STROKE-2022-040302_file1.docx

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STR_STROKE-2022-040302_supp1.pdf STR_STROKE-2022-040302_supp2.pdf STR_STROKE-2022-040302_supp3.jpg STR_STROKE-2022-040302_Xi_43990_copyright.pdf STR_STROKE-2022-040302_Xi_43990_external_disclosure.pdf STR_STROKE-2022-040302_ye_735257_external_disclosure.pdf STR_STROKE-2022-040302_ye_735257_copyright.pdf STR_STROKE-2022-040302_Keep_43742_copyright.pdf STR_STROKE-2022-040302_Keep_43742_external_disclosure.pdf STR_STROKE-2022-040302_Hua_44740_copyright.pdf STR_STROKE-2022-040302_Hua_44740_external_disclosure.pdf STR_STROKE-2022-040302_Yang_764850_external_disclosure.pdf STR_STROKE-2022-040302_Yang_764850_copyright.pdf STROKE-2022-040302_legacy.xml Has two supplement PDFs. Has graphic abstract. Charge authors for color. This manuscript was sent to Jaroslaw Aronowski, Guest Editor, for review by expert referees, editorial decision, and final disposition. Funding: Howard Hughes Medical Institute (HHMI): No National Institutes of Health (NIH): No Not applicable for this manuscript: No Other: No Wellcome Trust: No Subject Codes: [10177] Intracranial Hemorrhage ecain