PMID- 32560730 OWN - NLM STAT- MEDLINE DCOM- 20210520 LR - 20210520 IS - 1742-2094 (Electronic) IS - 1742-2094 (Linking) VI - 17 IP - 1 DP - 2020 Jun 19 TI - Intracerebral overexpression of miR-669c is protective in mouse ischemic stroke model by targeting MyD88 and inducing alternative microglial/macrophage activation. PG - 194 LID - 10.1186/s12974-020-01870-w [doi] LID - 194 AB - BACKGROUND: Ischemic stroke is a devastating disease without a cure. The available treatments for ischemic stroke, thrombolysis by tissue plasminogen activator, and thrombectomy are suitable only to a fraction of patients and thus novel therapeutic approaches are urgently needed. The neuroinflammatory responses elicited secondary to the ischemic attack further aggravate the stroke-induced neuronal damage. It has been demonstrated that these responses are regulated at the level of non-coding RNAs, especially miRNAs. METHODS: We utilized lentiviral vectors to overexpress miR-669c in BV2 microglial cells in order to modulate their polarization. To detect whether the modulation of microglial activation by miR-669c provides protection in a mouse model of transient focal ischemic stroke, miR-669c overexpression was driven by a lentiviral vector injected into the striatum prior to induction of ischemic stroke. RESULTS: Here, we demonstrate that miR-669c-3p, a member of chromosome 2 miRNA cluster (C2MC), is induced upon hypoxic and excitotoxic conditions in vitro and in two different in vivo models of stroke. Rather than directly regulating the neuronal survival in vitro, miR-669c is capable of attenuating the microglial proinflammatory activation in vitro and inducing the expression of microglial alternative activation markers arginase 1 (Arg1), chitinase-like 3 (Ym1), and peroxisome proliferator-activated receptor gamma (PPAR-gamma). Intracerebral overexpression of miR-669c significantly decreased the ischemia-induced cell death and ameliorated the stroke-induced neurological deficits both at 1 and 3 days post injury (dpi). Albeit miR-669c overexpression failed to alter the overall Iba1 protein immunoreactivity, it significantly elevated Arg1 levels in the ischemic brain and increased colocalization of Arg1 and Iba1. Moreover, miR-669c overexpression under cerebral ischemia influenced several morphological characteristics of Iba1 positive cells. We further demonstrate the myeloid differentiation primary response gene 88 (MyD88) transcript as a direct target for miR-669c-3p in vitro and show reduced levels of MyD88 in miR-669c overexpressing ischemic brains in vivo. CONCLUSIONS: Collectively, our data provide the evidence that miR-669c-3p is protective in a mouse model of ischemic stroke through enhancement of the alternative microglial/macrophage activation and inhibition of MyD88 signaling. Our results accentuate the importance of controlling miRNA-regulated responses for the therapeutic benefit in conditions of stroke and neuroinflammation. FAU - Kolosowska, Natalia AU - Kolosowska N AD - University of Eastern Finland, A.I. Virtanen Institute for Molecular Sciences, P.O. Box 1627, FI-70211, Kuopio, Finland. FAU - Gotkiewicz, Maria AU - Gotkiewicz M AD - University of Eastern Finland, A.I. Virtanen Institute for Molecular Sciences, P.O. Box 1627, FI-70211, Kuopio, Finland. FAU - Dhungana, Hiramani AU - Dhungana H AD - University of Eastern Finland, A.I. Virtanen Institute for Molecular Sciences, P.O. Box 1627, FI-70211, Kuopio, Finland. FAU - Giudice, Luca AU - Giudice L AD - Department of Computer Science, University of Verona, Verona, Italy. FAU - Giugno, Rosalba AU - Giugno R AD - Department of Computer Science, University of Verona, Verona, Italy. FAU - Box, Daphne AU - Box D AD - University of Eastern Finland, A.I. Virtanen Institute for Molecular Sciences, P.O. Box 1627, FI-70211, Kuopio, Finland. FAU - Huuskonen, Mikko T AU - Huuskonen MT AD - University of Eastern Finland, A.I. Virtanen Institute for Molecular Sciences, P.O. Box 1627, FI-70211, Kuopio, Finland. FAU - Korhonen, Paula AU - Korhonen P AD - University of Eastern Finland, A.I. Virtanen Institute for Molecular Sciences, P.O. Box 1627, FI-70211, Kuopio, Finland. FAU - Scoyni, Flavia AU - Scoyni F AD - University of Eastern Finland, A.I. Virtanen Institute for Molecular Sciences, P.O. Box 1627, FI-70211, Kuopio, Finland. FAU - Kanninen, Katja M AU - Kanninen KM AD - University of Eastern Finland, A.I. Virtanen Institute for Molecular Sciences, P.O. Box 1627, FI-70211, Kuopio, Finland. FAU - Yla-Herttuala, Seppo AU - Yla-Herttuala S AD - University of Eastern Finland, A.I. Virtanen Institute for Molecular Sciences, P.O. Box 1627, FI-70211, Kuopio, Finland. FAU - Turunen, Tiia A AU - Turunen TA AD - University of Eastern Finland, A.I. Virtanen Institute for Molecular Sciences, P.O. Box 1627, FI-70211, Kuopio, Finland. FAU - Turunen, Mikko P AU - Turunen MP AD - University of Eastern Finland, A.I. Virtanen Institute for Molecular Sciences, P.O. Box 1627, FI-70211, Kuopio, Finland. FAU - Koistinaho, Jari AU - Koistinaho J AD - University of Eastern Finland, A.I. Virtanen Institute for Molecular Sciences, P.O. Box 1627, FI-70211, Kuopio, Finland. AD - Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland. FAU - Malm, Tarja AU - Malm T AD - University of Eastern Finland, A.I. Virtanen Institute for Molecular Sciences, P.O. Box 1627, FI-70211, Kuopio, Finland. tarja.malm@uef.fi. LA - eng GR - 607962/Seventh Framework Programme (Marie Sklodowska-Curie Initial Training Network nEUROinflammation)/ GR - 607962/Seventh Framework Programme (Marie Sklodowska-Curie Initial Training Network nEUROinflammation)/ GR - none/Antti and Tyyne Soininen Foundation/ GR - none/Emil Aaltosen Saatio/ GR - 298071/Academy of Finland/ PT - Journal Article DEP - 20200619 PL - England TA - J Neuroinflammation JT - Journal of neuroinflammation JID - 101222974 RN - 0 (MicroRNAs) RN - 0 (Myd88 protein, mouse) RN - 0 (Myeloid Differentiation Factor 88) SB - IM MH - Animals MH - Cells, Cultured MH - Cerebral Ventricles/*metabolism MH - Disease Models, Animal MH - Ischemic Stroke/genetics/*metabolism MH - Macrophage Activation/*physiology MH - Macrophages/*metabolism MH - Mice MH - MicroRNAs/genetics/*metabolism MH - Microglia/*metabolism MH - Myeloid Differentiation Factor 88/*metabolism MH - Neurons/metabolism MH - Signal Transduction/physiology PMC - PMC7304130 OTO - NOTNLM OT - Functional improvement OT - MicroRNAs OT - Microglia/macrophage activation OT - Neuroinflammation OT - Stroke COIS- The authors declare that they no competing financial interests. EDAT- 2020/06/21 06:00 MHDA- 2021/05/21 06:00 PMCR- 2020/06/19 CRDT- 2020/06/21 06:00 PHST- 2019/10/30 00:00 [received] PHST- 2020/06/08 00:00 [accepted] PHST- 2020/06/21 06:00 [entrez] PHST- 2020/06/21 06:00 [pubmed] PHST- 2021/05/21 06:00 [medline] PHST- 2020/06/19 00:00 [pmc-release] AID - 10.1186/s12974-020-01870-w [pii] AID - 1870 [pii] AID - 10.1186/s12974-020-01870-w [doi] PST - epublish SO - J Neuroinflammation. 2020 Jun 19;17(1):194. doi: 10.1186/s12974-020-01870-w.