Inhibitory effect of α-MSH through MC1R on LTA-induced expression of HK TLR2 and IL-8.

<p>HK cells were treated with LTA, which were pre-incubated with α-MSH for 2 hours in the presence or absence of ASP as described in “Materials and Methods”. (<b>a</b>) The expression of HK TLR2 mRNA was measured by real-time RT-PCR 3 hours after <i>S</i>. <i>aureus</i>-derived LTA treatment. (<b>b</b>) TLR2 protein expression was determined by Western blot analysis using specific anti-human TLR2 polyclonal antibody (1:1000 dilution) and anti-β-actin antibody (1:5000 dilution) 24 hours after LTA treatment. (<b>c</b>) The expression of HK IL-8 mRNA was measured by real-time RT-PCR 3 hours after <i>S</i>. <i>aureus</i>-derived LTA treatment. (<b>d</b>) LTA-induced HK IL-8 secretion was measured by ELISA. HK treated with PBS served as a negative control. The relative intensity of expression was normalized using the expression of 18S rRNA for mRNA and β-actin for protein as internal controls. All values are expressed as mean ± SD. Statistically significant differences in the expression of HK TLR2 were determined by ANOVA with probabilities shown for both the overall significance and the pairwise comparison (*<i>P</i><0.001).