Effects of high glucose, miR-133a precursor or miR-133a inhibitor on human islet PTB protein levels (A) and insulin biosynthesis rates (B).

<p>In A, human islet cells were dispersed by trypsin treatment and lipofected with control RNA, miR-133a precursor or miR-133a inhibitor using Dharmafect I. Two days after the lipofection cells were cultured for another 24 hours in either 5.6 or 20 mM glucose. Islets were washed and harvested for SDS-PAGE and immunoblotting with anti-PTB antibodies. Lower panel shows PTB and tubulin immunoreactivity from one representative experiment. In B, human islets were transfected and cultured as in A and insulin biosynthesis rates were determined as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0010843#pone-0010843-t001" target="_blank">Table 1</a>. Insulin biosynthesis rates were expressed as percentage insulin biosynthesis per total protein biosynthesis. Results are means ± SEM for 3–4 observations. * denotes p<0.05 using paired Student's t-test when comparing vs. control.