title: Multipotent mesenchymal stromal cells decrease transforming growth factor β1 expression in microglia/macrophages and down-regulate plasminogen activator inhibitor 1 expression in astrocytes after stroke.
abstract: Multipotent mesenchymal stromal cells (MSCs) decrease the expression of transforming growth factor β1 (TGFβ1) in astrocytes and subsequently decrease astrocytic plasminogen activator inhibitor 1 (PAI-1) level in an autocrine manner. Since activated microglia/macrophages are also a source of TGFβ1 after stroke, we therefore tested whether MSCs regulate TGFβ1 expression in microglia/macrophages and subsequently alters PAI-1 expression after ischemia. TGFβ1 and its downstream effector phosphorylated SMAD 2/3 (p-SMAD 2/3) were measured in mice subjected to middle cerebral artery occlusion (MCAo). MSC treatment significantly decreased TGFβ1 protein expression in both astrocytes and microglia/macrophages in the ischemic boundary zone (IBZ) at day 14 after stroke. However, the p-SMAD 2/3 was only detected in astrocytes and decreased after MSC treatment. In vitro, RT-PCR results showed that the TGFβ1 mRNA level was increased in both astrocytes and microglia/macrophages in an astrocyte-microglia/macrophage co-culture system after oxygen-glucose deprived (OGD) treatment. MSCs treatment significantly decreased the above TGFβ1 mRNA level under OGD conditions, respectively. OGD increased the PAI-1 mRNA in astrocytes in the astrocyte-microglia/macrophage co-culture system, and MSC administration significantly decreased this level. PAI-1 mRNA was very low in microglia/macrophages compared with that in astrocytes under different conditions. Western blot results also verified that MSC administration significantly decreased p-SMAD 2/3 and PAI-1 level in astrocytes in astrocyte-microglia/macrophage co-culture system under OGD conditions. Our in vivo and in vitro data, in concert, suggest that MSCs decrease TGFβ1 expression in microglia/macrophages in the IBZ which contribute to the down-regulation of PAI-1 level in astrocytes.
authors.affiliation: Department of Neurology, Henry Ford Health System, Detroit, MI 48202, United States.
authors.forename: Hongqi
authors.initials: H
authors.lastname: Xin
authors.forename: Michael
authors.initials: M
authors.lastname: Chopp
authors.forename: Li Hong
authors.initials: LH
authors.lastname: Shen
authors.forename: Rui Lan
authors.initials: RL
authors.lastname: Zhang
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.forename: Zheng Gang
authors.initials: ZG
authors.lastname: Zhang
authors.forename: Yi
authors.initials: Y
authors.lastname: Li
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D015687:Cell Hypoxia; D018920:Coculture Techniques; D015536:Down-Regulation; D005947:Glucose / Q000378:metabolism; D020244:Infarction, Middle Cerebral Artery / Q000150:complications; D008264:Macrophages / Q000378:metabolism*; D045164:Mesenchymal Stem Cell Transplantation; D051379:Mice; D008810:Mice, Inbred C57BL; D017628:Microglia / Q000378:metabolism*; D017395:Plasminogen Activator Inhibitor 1 / Q000378:metabolism*; D020521:Stroke / Q000209:etiology / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D053773:Transforming Growth Factor beta1 / Q000378:metabolism*
chemical_list: D017395:Plasminogen Activator Inhibitor 1; D053773:Transforming Growth Factor beta1; D005947:Glucose