dulation is one of the pathways required for the TJ opening by capsaicin. The Actin Alteration Induced by Cofilin Correlates with the Reversibility of TJ Opening With the understanding that both cofilin dephosphorylation and a decrease in the level of occludin are necessary for efficient TJ opening, the contribution of each to the reversibility of TJ opening was investigated. For this purpose, cofilin dephosphorylation and the decrease in the level of occludin were analyzed for a longer period of time. Cofilin dephosphorylation was induced as early as 15 min after the addition of capsaicin and started to recover after 45 min. At 120 min, cofilin was phosphorylated almost to the same extent as before treatment. By contrast, the occludin decrease was significant throughout the entire time course from 45 to 360 min. Since the TER was decreased until 120 min and then started to increase to reach full 313348-27-5 manufacturer recovery at 360 min, cofilin phosphorylation/inactivation, rather than the decrease in occludin, preceded the recovery. To determine whether cofilin inactivation contributes to the recovery phase, actin alteration was analyzed by rhodaminephalloidin staining during the same time period as in Reversible TJ 
Open by Cofilin-Actin and Occludin level of occludin but correlates with the specific actin alterations induced by cofilin activation. Capsaicin Increases the Permeability of Non-ionic/Ionic Molecules in MDCK Monolayers TJ also control the permeability of the paracellular pathway, which can be measured via the diffusion of molecules of different sizes. The effect of capsaicin on the passage of three different molecules, 5-carboxyfluorescein, FITC-dextran-4, and insulin was assessed. The molecules were applied to the apical side of the MDCK monolayers in transwells to measure permeability. An approved rectal absorption enhancer, sodium decanoate , significantly increased the passage of CF and FD4. Capsaicin increased CF permeability to a similar extent as C10. Capsacin increased FD4 permeability more than C10 did. LatA also increased the permeability, at first to a lower extent than the other two agents, and 15168218 then to a larger extent Reversible TJ Open by Cofilin-Actin and Occludin passage of charged high molecular weight molecules is more sensitive to capsaicin recovery than the passage of low molecular weight or uncharged molecules. In conclusion, the present study demonstrates that capsaicin is capable of opening the TJ of epithelial cells in a reversible and concentration-dependent manner. Capsaicin modulates TJ through at least two mechanisms: changes in the polymerization state and subcellular distribution of actin, and a decrease in the TJ occludin level. Stable transfectants showed that both actindepolymerizing factor activation and a decreased level of occludin are important for the effective and significant TER decrease induced by capsaicin, although the recovery correlates with cofilin inactivation and actin assembly but not with decreased occludin. Finally, the study confirmed that capsaicin increases the paracellular permeability of both charged and uncharged compounds with spontaneous recovery, which is consistent 11414653 with a reversible decrease in TER. Taken together, the identification of the effect of capsaicin on TJ and that of a new mechanism of reversible TJ opening raise the possibility of developing a novel kind of PPE. Discussion In this study, capsaicin was shown to reversibly modulate the TER and paracellular permeability of M
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