RESUMEN
PIM (proviral integration site) kinases are a distinct class of serine/threonine-specific kinases consisting of PIM1, PIM2 and PIM3. PIM2 is known to function in apoptosis pathways. Expression of PIM2 is highly induced by pro-inflammatory stimuli but the role of PIM2 in the expression of pro-inflammatory cytokines is unclear. In this study, we showed that over-expression of PIM2 in HeLa cells as well as in human umbilical vein endothelial cells enhanced interleukin-1ß (IL-1ß) -induced and tumour necrosis factor-α-induced IL-6 expression, whereas over-expression of a kinase-dead PIM2 mutant had the opposite effect. Studies with small interfering RNA specific to PIM2 further confirmed that IL-6 expression in HeLa cells requires PIM2. To investigate the function of PIM2 further, we generated PIM2-deficient mice. It was found that IL-6 production was significantly decreased from PIM2-deficient spleen cells after stimulation with lipopolysaccharide. Taken together, we demonstrated an important function of PIM2 in controlling the expression of the pro-inflammatory cytokine IL-6. PIM2 inhibitors may be beneficial for IL-6-mediated diseases such as rheumatoid arthritis.
Asunto(s)
Regulación de la Expresión Génica/efectos de los fármacos , Interleucina-1beta/farmacología , Interleucina-6/biosíntesis , Lipopolisacáridos/farmacología , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Proto-Oncogénicas/metabolismo , Factor de Necrosis Tumoral alfa/farmacología , Animales , Proliferación Celular/efectos de los fármacos , Células Cultivadas , Células Endoteliales/efectos de los fármacos , Células Endoteliales/metabolismo , Células HeLa , Humanos , Interleucina-10/metabolismo , Interleucina-6/genética , Ratones , Ratones de la Cepa 129 , Ratones Endogámicos C57BL , Ratones Noqueados , Mutación/genética , FN-kappa B/metabolismo , Proteínas Serina-Treonina Quinasas/genética , Proteínas Proto-Oncogénicas/genética , ARN Interferente Pequeño/genética , Bazo/citología , Linfocitos T/citología , Linfocitos T/efectos de los fármacos , Linfocitos T/metabolismo , Transfección , Factor de Necrosis Tumoral alfa/genéticaRESUMEN
Protein kinase C theta (PKCtheta) is essential for T cell activation, as it is required for the activation of NF-kappaB and expression of IL-2. PKCtheta has also been shown to affect NFAT activation and Th2 differentiation. To better understand the role of PKCtheta in the regulation of T helper cells, we used PKCtheta-deficient DO11.10 transgenic T cells to study its role in vitro. DO11.10 Th1 cells deficient in PKCtheta produced significantly less TNF-alpha and IL-2. The expression of Th2 cytokines, including IL-4, IL-5, IL-10, IL-13 and IL-24 was significantly reduced in PKCtheta-deficient T cells. Moreover, the expression of the Th2 transcription factor, GATA3, was significantly reduced in PKCtheta-deficient T cells. Overexpression of GATA3 by retroviral infection in PKCtheta-deficient T cells resulted in increased expansion of IL-4-producing T cells and higher IL-4 production than that of wild type Th2 cells. IL-5, IL-10, IL-13 and IL-24 expressions were also rescued by GATA3 overexpression. Our observations suggest that PKCtheta regulates Th2 cytokine expression via GATA3.
