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. Author manuscript; available in PMC: 2009 Oct 6.
Published in final edited form as: Stem Cells. 2007 Oct 4;26(1):99–107. doi: 10.1634/stemcells.2007-0563

Figure 1. Human Mesenchymal Stem Cells (hMSCs) Express Toll-like Receptors (TLRs) and downstream signaling molecule, MyD88.

Figure 1

A. RNA was isolated from hMSCs and PBMC and analyzed by RT-PCR for expression of TLR 1−10. HPRT was used as loading control. hMSC expressed TLR 1, 2, 3, 4, 5, 6, and 9 whereas PBMC expressed TLR 1, 2, 4, 5, and 8 (n>3). B. Human MSC donor pools were routinely examined by flow cytometry for expression of discriminating MSC cell surface markers as described in Materials and Methods. Shown in bottom panels are representative findings for hMSCs: positive expression of CD90 and CD105 and mostly negative expression of CD45 and CD34 (n>12). HuMSCs were examined also by flow cytometry for expression of TLR2, 3, 4, 7, 9 and MyD88 as indicated by red filled-in curves on the top panels (n>7). The grey filled-in line represents hMSCs incubated with corresponding isotype antibody controls. C. Representative flow cytometry analysis of hMSCs for TLR3 and TLR4 after ligand stimulation for 30 min (Blue line) or without stimulation (constitutive expression, Red line). D. Antibody staining of TLRs was performed following fixation and membrane permeabilization of the ligand-treated hMSCs seeded on chamber slides. Samples were pre-treated for 1 h with ligands: 1 μM poly(I:C) (TLR3) or 10 ng/mL LPS (TLR2 & 4) prior to harvest and immunofluorescence (IF). As a control, the primary antibody was omitted from staining procedure (no 1o, n>3).