G₁ Cell Cycle Arrest Is Induced by the Fourth Extracellular Loop of Meningococcal PorA in Epithelial and Endothelial Cells

Figure 5

PorA-Loop4 peptide cause an increased expression of CDK4 and decreased expression of Cyclin D1 both at the mRNA and protein level. (a) HBMECs were either left untreated or treated with PorA-Loop4 (50 μM) for up to 24 h. RNA was extracted, cDNA was generated, and qRT-PCR was performed to analyze the mRNA expression of CDK4 and Cyclin D1. Bars represent the expression (2^-ΔΔC_T, fold change) of CDK4 and Cyclin D1 relative to GAPDH levels as the housekeeping gene. Data were normalized to the untreated cells. (b) The treated (24 h) and untreated HBMECs were collected and lysed for immunoblotting and densitometry analysis of p-CDK4 (Thr172)/Cyclin D1 protein expression. Alpha actinin was used to normalize protein loading. The figure shows a representative blot with lanes from different areas of the same membrane. Band intensities were quantified by densitometric analysis using Image J and normalized to alpha actinin. qRT-PCR and immunoblotting were each performed in three independent experiments. Significant difference to the untreated (, , , and ), -test.

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