HspB1 deficiency increases IL-1-induced IL-6 expression and inhibits proliferation in fibroblasts.

<p>A, Primary wild-type and <i>hspB1</i>^del/del MEF were treated with IL-1 (20 ng/ml) for 4 h or left untreated. Graph shows the concentration of IL-6 in culture medium as determined by ELISA and normalised against values for IL-1-treated wild-type MEF for three separate batches of cells (*P<0.05). B, MEF were treated as in (A), lysed, RNA extracted and IL-6 and GAPDH mRNAs quantified by qRT-PCR. Plot shows IL-6 mRNA/GAPDH mRNA normalised to the value for wild-type cells treated with IL-1 for 1 h. C, Growth curve analysis (means±SEM) of wild-type and <i>hspB1</i>^del/del MEF determined by MTT assay at different days post-seeding (n = 3; *P<0.05, **P<0.01, ***P<0.001) or by counting trypan-blue excluded cells (n = 2). D, Plot of mean (%) TUNEL-positive (± SEM) cells for three different batches of MEF per genotype. E, MEF were treated with different concentrations of doxorubicin (as indicated) for 8 h to induce apoptosis, or left untreated, cells lysed and lysates analysed by western blot for the full-length and the cleaved form of PARP. Similar results were obtained in three independent experiments.