Interleukin-9 receptor alpha subunit (IL9RA)

The Interleukin-9 receptor alpha subunit (IL9RA), also known as CD129, is a type I cytokine receptor that forms a functional heterodimer with the common gamma chain (IL2RG) to mediate the biological effects of interleukin-9 (IL-9). It is primarily expressed on mast cells, T cells, B cells, and hematopoietic progenitors, where it plays a pivotal role in regulating immune responses and cell survival. Upon ligand binding, IL9RA triggers the activation of Janus kinases (JAK1 and JAK3) and signal transducer and activator of transcription (STAT) proteins, specifically STAT1, STAT3, and STAT5. IL9RA signaling is critical for the pathogenesis of allergic diseases, such as asthma, by promoting mast cell expansion, IgE production, and airway hyperresponsiveness. Additionally, it is implicated in the development of certain lymphoid malignancies, including Hodgkin's lymphoma and T-cell lymphomas, through autocrine or paracrine growth stimulation. Therapeutic strategies targeting the IL-9/IL9RA axis include monoclonal antibodies against the IL-9 ligand, such as MEDI-528 and Enokizumab, and multi-specific inhibitors like BNZ-1 and EQ101 that block multiple common gamma chain cytokines. Experimental approaches also include chimeric toxins like rhIL-9-ETA that directly target IL9RA-expressing malignant cells.

Other names

IL9RCD129Interleukin-9 receptorIL-9RCD129 antigenCytokine receptor P40

Inhibition of the IL-9/IL9RA signaling axis via ligand neutralization, receptor blockade, or multi-cytokine inhibition, preventing JAK/STAT pathway activation.