Fig 2: Effect of IRW on paracellular tracer flux across Caco-2 cell monolayers. Cells were incubated with IRW (50 and 100 μM) for 24 h and then exposed to LPS (20 μg/mL) for 2 h. FITC-dextran 4 kDa (A) and 40 kDa (B) and Lucifer yellow (C) in PBS were added to the apical chamber, and solutions were collected from the basal chamber after 4 h of incubation for fluorescence detection by a microplate reader (SpectraMax M3, Molecular Devices, CA). The excitation and emission wavelengths for FITC-dextran are 490 and 520 nm, respectively, and 410 and 520 nm for Lucifer yellow. The results are representative of four independent experiments expressed as mean ± SEM. Ctrl means the control group. 50 and 100 IRW refer to the treatments with 50 and 100 μM IRW, respectively. 50 + LPS and 100 + LPS refer to the treatments with IRW (50 and 100 μM, respectively), followed by 20 μg/mL LPS. *P < 0.05, ***P < 0.001, significantly different from the control group. #P < 0.05, ##P < 0.01, significantly different from the LPS group.

Fig 3: Hsp70s suppress heat-induced aggregation of malate dehydrogenase. The heat-induced aggregation of the model substrate MDH was monitored using a SpectraMax M3 spectrometer (Molecular Devices, USA). The temperature was set at 51 °C, and the assay was performed at 340 nm. The aggregation of MDH in the absence of a chaperone was defined as 100% aggregation as a reference point. The capability of PfHsp70-xF, PfHsp70-xT and hHsp70 to suppress the heat-induced aggregation of MDH was monitored either in the presence of ATP/ADP. BSA was used as a non-chaperone control protein. Standard errors shown were obtained from three independent replicate assays. GraphPad Prism 9.0 was used to conduct one-way ANOVA to determine the significance of the differences (p < 0.05)*