The presence of EOS at the sites of allergic inflammation might release this constitutive intracellular IL-8 and RANTES (Rot and others 1992)

The presence of EOS at the sites of allergic inflammation might release this constitutive intracellular IL-8 and RANTES (Rot and others 1992). In the treated EOS cells with 75?nM of GCAs, we observed a wide range of potency in the inhibition of CCL26 and CCL11. was shown that EOS proliferation and activation were reduced considerably, and cell apoptosis occurred when exposed to nonfluorinated isoxazoline derivatives. These results provide evidence that concentration and structural manipulation of GCAs could increase the anti-inflammatory potency in treatment of chronic diseases, including asthma. Introduction The clinical use of glucocorticoids (GCs) in a wide variety of inflammatory and autoimmune disorders has THZ531 made them among the most widely prescribed drugs in the world. The anti-inflammatory treatment of using GCs may have wide effects inhibiting the generation of cytokines and chemokines, and inhibiting the development and recruitment of airway eosinophilia (Barnes 1995; Barnes and others 1998b; Lloyd 2002). However, the clinical use of corticosteroids is limited due to a number of serious systemic side effects, some of which are life threatening (Masi and Chrousos 1996; Nishimura and Ikuyama 2000; Alekseev and others 2001; Sambrook and others 2001). Considerable effort has been exerted to determine the mechanisms of GC activities during inflammation and asthma. GC molecules mainly target intracellular GC receptors (GRs), which are located in the cytosol of airway cells. After infiltrating the cell membrane, GCs bind to the GRs inactivated by association with multichaperone proteins (Barnes 1996), causing a conformation change that dissociates the GRs from the chaperone proteins. The GRs then dimerize, forming active GC-GR complexes that translocate from the cytosol to the nucleus of the cell, where they bind to specific DNA sequences called glucocorticoid-response elements (GREs) in the promoter region of the GC-regulated genes (Encio and Detera-Wadleigh 1991; Muller and Renkawitz 1991). The GR-GRE association leads directly to transcription activation or repression of the target gene during the inflammatory process. The GC-GR complex can also indirectly interact with transcription factors such as AP-1 or NF-kB to decrease the transcription of many disease-specific genes, including chemoattractants, cytokines, cytokine receptors, and cell adhesion molecules. This transrepression process involves recruitment of histone deacetylases and modulation of THZ531 the chromatin structure (Adcock and Ito 2000). The effects of GCs on post-transcriptional mechanisms have also been suggested. GCs induce mRNA destabilization and decrease the protein secretion of cytokines interleukin (IL)-1 and IL-6 (Kern and others 1988; Amano and others 1993). GCs can also decrease the expression of the IL-4R receptor during post-transcription, as well as during the translational or post-translational process in response to gene induction (Mozo and others 1998). Overall, the shortcomings of steroid therapy are largely inherent in their structural features. A considerable amount of research has been conducted to increase the therapeutic index of potent corticosteroids by reducing their systemic side effects. While THZ531 many new steroids have been obtained by extension of traditional molecular and structural manipulations, new GC molecules with significant structural changes have also been developed (Alekseev and others 2001). Glucocorticoid antedrugs (GCAs) are designed compounds that exert desirable effects at the application site, but are rapidly biotransformed to an inactive metabolite by a predictable enzymatic reaction upon entry into the circulation, thus resulting in reduction of adverse systemic effects such as suppressive effect on the hypothalamusCadrenal THZ531 axis (Lee and Soliman 1982; STMN1 Lee and Ko 1999). The common structural feature found in GCAs is the incorporation of a new metabolically labile functionality such as a carboxyester, lactone, or isoxazoline, which is hydrolyzed to an inactive metabolite by enzymes in the circulation (Kimura 1994; Little and others 1999; Procopiou and others 2001; Sawa and others 2002; You and others 2002). Although this concept was developed to synthesize anti-inflammatory steroids, its application has been expanded to other classes of agents. Diversity in therapeutic and structural classes of GCAs has also grown (Bodor 2000; Hwang and others 2000; Ji and others 2000; Khan and others 2005). In accordance with the antedrug concept, our laboratory synthesized fused heterocyclosteroidal antedrugs of [16, 17-d]-3- hydroxy-iminoformyl isoxazoline and [16, 17-d] isoxazoline derivatives from the molecular parents prednisolone (PRED), 9–fluoroprednisolone (FPRED), and 21-acethyloxy-FPRED FP-21AC (Kwon and others 1995, 2006; Khalil and others 1996; Ko and others 1997). Previously, these compounds showed dose-dependent anti-inflammatory effects in an ear edema bioassay, and displayed no significant suppressive effects on corticosterone levels or thymus weights in the 5-day multiple-dose edema assay (Khalil and others 1996; Ko and THZ531 others 1997; Park and others 2006). Chemokines are a superfamily of over 50 small secreted proteins so named for their precise orchestration of leukocyte trafficking in both homeostatic and disease states. Within the.