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. Author manuscript; available in PMC: 2013 Jul 1.
Published in final edited form as: Stem Cells. 2012 Jul;30(7):1556–1564. doi: 10.1002/stem.1129

Figure 3.

Figure 3

MSC exosomes containing microRNA 133b (miR-133b) are transferred to neural cells. Real-time reverse-transcribed PCR revealed that compared to exosome-enriched fraction deprived media, exosome-enriched fractions collected from MSCs exposed to middle cerebral artery occlusion (MCAo) brain extracts significantly increased the miR-133b level in astrocytes (A) and neurons (B), respectively. Compared with astrocytes and neurons treated with exosome-enriched fractions from MSCs exposed to normal rat brain tissue extracts, miR-133b levels were significantly increased in astrocytes and neurons treated with exosome-enriched fractions from MSCs exposed to 24, 72, or 168 hours post-MCAo brain tissue extracts, and the miR-133b level was maximum at the 72 hours post-MCAo brain tissue extract exposure (A, B). To further confirm that the increased parenchymal cell miR-133b is attributed to the transfer of exosomes generated by MSCs, MSCs were transfected with a miR-133b inhibitor and the miR-133b level was significantly decreased in the MSCs and their exosome-enriched fractions (C). Compared with normal cultured astrocytes, treatment with exosome-enriched fractions from MSCs transfected with the miR-133b inhibitor negative control significantly increased the miR-133b level in the astrocytes, but this increase in miR-133b was significantly diminished when astrocytes were treated with exosome-enriched fractions from MSCs transfected with miR-133b inhibitor. The exosome-enriched fraction deprived media either from MSCs transfected with miR-133b inhibitor negative control or from MSCs transfected with miR-133b inhibitor had no obvious effects on the miR-133b level in astrocytes (D). MeC, EC: media and exosome-enriched fractions from MSCs treated with the normal rat brain tissue extracts as controls, respectively; Me24, Me72, Me168, E24, E72, and E168: media- and exosome-enriched fractions from MSCs treated with the MCAo rat brain tissue extracts for 24, 72, and 168 hours, respectively; NOR: normal cultured astrocytes; MeN, MeI: astrocytes treated with exosome-enriched fraction deprived media from MSCs transfected with miR-133b inhibitor negative control and miR-133b inhibitor, respectively; EN, EI: astrocytes treated with exosome-enriched fractions from MSCs transfected with miR-133b inhibitor negative control and miR-133b inhibitor, respectively. *, p < .05 compared with EC in (A) and (B); compared with negative control, respectively, in (C); compared with NOR in (D). #, p < .05 compared with MeC in (A) and (B); compared with EN in (D) (n = 3 per group). Abbreviation: MSC, mesenchymal stromal cell.