The Effect of the JNK Inhibitor, JIP Peptide, on Human T Lymphocyte Proliferation and Cytokine Production

Abstract

Although JNK is a potential target for treating chronic inflammatory diseases, its role in T lymphocyte function remains controversial. To overcome some of the previous limitations in addressing this issue we have used the recently described transactivator of transcription-JNK-interacting protein (TAT-JIP) peptide, a specific inhibitor that was derived from the minimal JNK-binding region of the scaffold protein, JNK-interacting protein 1 (JIP-1), coupled to the short cell-permeable HIV TAT sequence. Pretreatment of purified human T lymphocytes with the TAT-JIP peptide inhibited the phosphorylation of endogenous jun activated by PHA-PMA. This was associated with a corresponding inhibition of lymphoproliferation, and of IL-2, IFN-γ, lymphotoxin, and IL-10 cytokine production. Similar results were also found using mouse splenic T cells. Examination of the specificity of TAT-JIP revealed that although the peptide was more selective than the pharmacological inhibitor, SP600125, it also inhibited cyclin-dependent kinase 2, p70 ribosomal protein S6 kinase, and serum and glucocorticoid-regulated kinase activity. Nevertheless, these data demonstrate for the first time the ability of the TAT-JIP peptide to inhibit the JNK pathway and the phosphorylation of jun in intact cells, thereby preventing the activation of the transcription factor, AP-1, and the production of Th1 and Th2 cytokines. Thus JNK could potentially be a target for the development of drugs for the treatment of autoimmune inflammatory diseases.

Identification and Characterization of a Novel Class of c-Jun N-terminal Kinase Inhibitors

“…Indeed, splitting the total daily dose has been reported to be more effective than the same dose given once daily (Albert et al, 2006). JNK signaling pathways play an important role in T-cell activation and cell proliferation during inflammatory responses (Sabapathy et al, 1999;Bennett et al, 2001;Chialda et al, 2005;Melino et al, 2008). For example, JNK inhibitor SP600125 has been reported to inhibit activation and differentiation of primary human CD4 ϩ T cell cultures , to inhibit paw swelling in a mouse model of collagen induced adjuvant arthritis (Gaillard et al, 2005), and to attenuate lung inflammation in an OVA-induced murine asthma model (Chialda et al, 2005).…”

Protein Kinase Cα Regulates the Expression of Complement Receptor Ig in Human Monocyte–Derived Macrophages

“…Cytokine assays IL-6, TNF-a, and IL-1b levels were determined using cytometric bead array according to the manufacturer's instructions and as described previously (22). In brief, 50 ml capture bead suspension and 50 ml PE detection reagent were added to an equal amount of sample or standard dilution and incubated for 2 h at room temperature in the dark.…”

Gene Related to Anergy in Lymphocytes (GRAIL) Expression in CD4+ T Cells Impairs Actin Cytoskeletal Organization during T Cell/Antigen-presenting Cell Interactions

“…The role of JNK phosphorylation in T cell activation remains controversial with some reports suggesting JNK may be dispensable for T cell proliferation and cytokine production (40,41). Nonetheless, in several model systems, blockade of JNK activation has been shown to abrogate IL-2 production and proliferation in T cells (42,43). Biochemical signaling in response to stimulation with PMA/ ionomycin was previously interrogated in GRAIL-expressing Jurkat T cells, and JNK phosphorylation was comparable to the control Jurkat T cells (44).…”