Key Event Title
|Level of Biological Organization|
Key Event Components
Key Event Overview
AOPs Including This Key Event
|AOP Name||Role of event in AOP|
|Immune dysfunction induced by JAK3 inhibition||KeyEvent|
|Homo sapiens||Homo sapiens||High||NCBI|
|Mus musculus||Mus musculus||High||NCBI|
|All life stages||High|
Key Event Description
IL-4 is mammalian protein found in Homo sapiens. IL-4 plays a pivotal role in shaping the nature of immune responses. Upon activation, naive peripheral CD4+ T cells begin to synthesize and secrete cytokines. Type 2 helper cells (Th2 cells) produce IL-4, IL-5, IL-6, and IL-13. IL-4 is a 15-kD polypeptide with pleiotropic effects on many cell types. In T cells, binding of IL-4 to its receptor induces proliferation and differentiation into Th2 cells. Th2 cells provide help for B cells to promote class switching from IgM to IgG1 and IgE (56-Choi-1998).
STAT5 phosphorylation facilitates STAT5 dimerization, transport to the nucleus and gene regulation (57-Levy-2002). DNaseI hypersensitivity sites II (HSⅡ) and III (HSⅢ) in intron 2 were included in several regions of the Il4/Il13 locus. STAT5A binds to the sites near HSⅡ and HSⅢ, which could provide a mechanism through which STAT5A mediates IL-4 gene accessibility and participates in the induction of IL-4 production (32-Zhu-2003). The CD3 antibody-induced phosphorylation of STAT5 was down regulated by Tofacitinib, suggesting that JAK3 inhibition by Tofacitinib down regulated STAT5-dependent cytokine signaling. Tofacitinib abrogated anti-CD3-induced STAT5 activation in CD4+ T cells and inhibited IL-4 production from CD4+ T cells (58-Migita-2011).
How It Is Measured or Detected
CD4+ T cells were stimulated with CD3 monoclonal antibodies in the presence or absence of tofacitinib (CP690,550) for 48 hr. Supernatants were collected and the levels of IL-4 production was measured by ELISA (58-Migita-2011).
CD4+ T cells were stimulated with CD3 monoclonal antibodies in the presence or absence of tofacitinib. After 8-hr or 24-hr stimulation, total RNA was extracted and IL-4 mRNA expression was measured by real-time PCR (58-Migita-2011).
Flow cytometry analysis (intracellular staining) were used for measurement of cytosolic IL-4 content in stimulated cells (59-Zhu-2001).
Relative gene expression levels were determined by quantitative RT-PCR using Taqman Gene Expression primer probe sets and ABI PRISM 7700 or 7900 Taqman systems (Applied Biosystems). The comparative threshold cycle method and internal controls (cyclophillin or β-actin) were used to normalize expression of target gene (IL-4) (60-Ghoreschi-2011).
Quantitation of cytokine content was done on appropriately diluted samples, run in duplicate, using Sandwich Enzyme-Linked Immuno Sorbent Assay (ELISA) kits to test matched antibody pairs with biotin-horseradish peroxidase-streptavidin detection and 3,3',5,5'-tetramethylbenzidine substrate. ELISA plates were scanned in a Molecular Devices UVmax plate reader (Menlo Park, CA), using SOFT max software (Molecular Devices) (61-Dumont-1998)
Domain of Applicability
Only 1% of CD4 T cells from STAT5a-/- mice primed with soluble anti-CD3 and anti-CD28 with IL-2 produced IL-4, whereas 10.5% of control C57BL/6 CD4 T cells produced IL-4 (62-Cote-Sierra-2004).
Cells from STAT5A-deficient mice or cells treated with phospho-STAT5 peptide are defective in Th2 differentiation. STAT5A single deficient mice showed impaired Th2 differentiation, and reconstituting STAT5A by retroviral infection restored the capacity of cells to make IL-4 (63-Kagami-2001).
IL-2 directly activates STAT5A and STAT5B. T cells from mice deficient in either STAT5A or STAT5B did not show a dramatic change in T cell proliferation, but cells from mice in which both have been knocked out proliferate poorly in response to IL-4 (25-Moriggl-1999).
Evidence for Perturbation by Stressor
25. Moriggl, R., Topham, D. J., Teglund, S., Sexl, V., McKay, C., Wang, D., Hoffmeyer, A., van Deursen, J., Sangster, M. Y., Bunting, K. D., Grosveld, G. C., and Ihle, J. N. (1999) Stat5 is required for IL-2-induced cell cycle progression of peripheral T cells. Immunity 10, 249-259
32. Zhu, J., Cote-Sierra, J., Guo, L., and Paul, W. E. (2003) Stat5 activation plays a critical role in Th2 differentiation. Immunity 19, 739-748
56. Choi, P., and Reiser, H. (1998) IL-4: role in disease and regulation of production. Clin Exp Immunol 113, 317-319
57. Levy, D. E., and Darnell, J. E., Jr. (2002) Stats: transcriptional control and biological impact. Nature reviews. Molecular cell biology 3, 651-662
58. Migita, K., Miyashita, T., Izumi, Y., Koga, T., Komori, A., Maeda, Y., Jiuchi, Y., Aiba, Y., Yamasaki, S., Kawakami, A., Nakamura, M., and Ishibashi, H. (2011) Inhibitory effects of the JAK inhibitor CP690,550 on human CD4(+) T lymphocyte cytokine production. BMC Immunol 12, 51
59. Zhu, J., Guo, L., Watson, C. J., Hu-Li, J., and Paul, W. E. (2001) Stat6 is necessary and sufficient for IL-4's role in Th2 differentiation and cell expansion. J Immunol 166, 7276-7281
60. Ghoreschi, K., Jesson, M. I., Li, X., Lee, J. L., Ghosh, S., Alsup, J. W., Warner, J. D., Tanaka, M., Steward-Tharp, S. M., Gadina, M., Thomas, C. J., Minnerly, J. C., Storer, C. E., LaBranche, T. P., Radi, Z. A., Dowty, M. E., Head, R. D., Meyer, D. M., Kishore, N., and O'Shea, J. J. (2011) Modulation of innate and adaptive immune responses by tofacitinib (CP-690,550). J Immunol 186, 4234-4243
61. Dumont, F. J., Staruch, M. J., Fischer, P., DaSilva, C., and Camacho, R. (1998) Inhibition of T cell activation by pharmacologic disruption of the MEK1/ERK MAP kinase or calcineurin signaling pathways results in differential modulation of cytokine production. J Immunol 160, 2579-2589
62. Cote-Sierra, J., Foucras, G., Guo, L., Chiodetti, L., Young, H. A., Hu-Li, J., Zhu, J., and Paul, W. E. (2004) Interleukin 2 plays a central role in Th2 differentiation. Proc Natl Acad Sci U S A 101, 3880-3885
63. Kagami, S., Nakajima, H., Suto, A., Hirose, K., Suzuki, K., Morita, S., Kato, I., Saito, Y., Kitamura, T., and Iwamoto, I. (2001) Stat5a regulates T helper cell differentiation by several distinct mechanisms. Blood 97, 2358-2365