The ubiquitous role of spleen tyrosine kinase (Syk) in gut diseases: From mucosal immunity to targeted therapy

Abstract

Spleen tyrosine kinase (Syk) is a cytoplasmic non-receptor protein tyrosine kinase expressed in a variety of cells and play crucial roles in signal transduction. Syk mediates downstream signaling by recruiting to the dually phosphorylated immunoreceptor tyrosine-based activation motifs (ITAMs) of the transmembrane adaptor molecule or the receptor chain itself. In gut diseases, Syk is observed to be expressed in intestinal epithelial cells, monocytes/macrophages, dendritic cells and mast cells. Activation of Syk in these cells can modulate intestinal mucosal immune response by promoting inflammatory cytokines and chemokines production, thus regulating gut homeostasis. Due to the restriction of specificity and selectivity for the development of Syk inhibitors, only a few such inhibitors are available in gut diseases, including intestinal ischemia/reperfusion damage, infectious disease, inflammatory bowel disease, etc. The promising outcomes of Syk inhibitors from both preclinical and clinical studies have shown to attenuate the progression of gut diseases thereby indicating a great potential in the development of Syk targeted therapy for treatment of gut diseases. This review depicts the characterization of Syk, summarizes the signal pathways of Syk, and discusses its potential targeted therapy for gut diseases.

Keywords:

• Spleen tyrosine kinase
• gut diseases
• mucosal immunity
• targeted therapy
• intestinal homeostasis

Disclosure statement

The authors declare that they have no competing interests.

Additional information

Funding

This work was supported by grants from Distinguished Scholars Foundation of Jiangsu Province (JCRCB2016006), 333 High Level Talents Training Project of Jiangsu Province (BRA2019011), and General Project of Military Logistics Research (CLB19J025).