Mesenchymal Stromal Cells Accelerate Epithelial Tight Junction Assembly via the AMP-Activated Protein Kinase Pathway, Independently of Liver Kinase B1

Figure 2

Impact of mesenchymal stromal cells (MSC) on AMPK activation and ZO-1 relocation following a Ca²⁺ switch in MDCK cells. Representative immunoblotting (a) and quantifications (b) of phospho-acetyl-Coa carboxylase (pACC), phospho-AMP-activated protein kinase (pAMPK), and total AMPK (AMPKt) in low Ca²⁺ conditions (S-MEM) and following Ca²⁺ switch using MDCK cells or LKB1-shRNA MDCK cells, with versus without MSC. Compounds STO-609 and C were used as CaMKK and AMPK inhibitors, respectively. Quantifications of immunoreactive signals were performed by stain-free method after normalization to total protein content of each lane. Data are presented as mean ± SD; ns: not significant, , . Representative immunofluorescence (c) and quantifications (d) of ZO-1 deposits at increasing time points following Ca²⁺ switch in similar conditions as in (a) and (b) (scale bar: 16 μm). MSC/MDCK (i.e., MDCK (^§) or MDCK LKB1-shRNA ()) cocultures show significantly increased ZO-1 deposits at 1-hour post Ca²⁺ switch in comparison to MDCK alone. At 2 hours post Ca²⁺ switch, no significant (ns) difference in ZO-1 lengths is observed between MDCK and MSC/MDCKs. Data are presented as mean ± SD.

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