C5AR1

Background

C5aR1, also known as CD88 (cluster of differentiation 88), is a seven-transmembrane protein expressed on myeloid, endothelial, epithelial, and smooth muscle cells, belonging to the family of G-protein-coupled receptors (GPCRs). It is a receptor for C5a, the most potent chemotactic and inflammatory peptide. Structurally, there have at least two sites on the receptor interacting with the ligand C5a, one is on the extracellular N-terminus and the other is in the transmembrane region. Functionally, C5aR1 activation is involved in the stimulation of chemotaxis, granule enzyme release, intracellular calcium release, and the production of superoxide anion. C5aR1 also serves as a component of the classical pathway of the complement cascade, participating in the host-defense responses. Furthermore, C5aR1 may be a component of the membrane attack complex, involved in tissue injury associated with ischemia or sepsis.

Because of the crucial role in the regulation of inflammatory responses, C5aR1 signaling pathway has been revealed an association with some inflammatory diseases such as cancer. C5aR1 has been found in a variety of tumor cell types such as colon, esophagus, stomach, bile duct, liver, and breast. High levels of C5aR1 in human tumor cells are greatly associated with poor prognosis, such as shorter recurrence-free survival, overall survival, and bone metastasis. Blockage of C5aR1 can impair tumor cell growth and metastasis. Furthermore, C5aR1 signaling pathway has been also indicated a key role in acute lung injury induced by influenza virus infection. C5a-C5aR1 inhibition can suppress the viral replication in lung tissue, thereby alleviating the symptoms of acute lung injury.

Fig. 1 Structure of C5aR. Distributed under CC BY 3.0, from Wiki, without modification.

C5AR1 Functional Service

Creative Biolabs provides an extensive portfolio of C5AR1-focused products, such as anti-C5AR1 antibodies and aptamers, C5AR1 ELISA detection kits, recombinant C5AR1 proteins, and blocking peptides. These meticulously designed tools are critical for propelling research initiatives that develop therapeutic strategies across a wide range of diseases.

Fig.2 Association between complement activation and colorectal cancer.¹

The involvement of various factors such as myeloid-derived suppressor cells (MDSCs), immune cells, cytokines, and chemokines in colorectal cancer (CRC) remains complex, with the underlying mechanisms still not fully understood. Researchers have explored the complement system’s critical role in immune regulation as a key player in this process. Utilizing a CRC murine model, including wild-type and complement-deficient mice, researchers employed flow cytometry and immunohistochemical techniques. Findings revealed that complement activation, specifically C5a/C5aR1 signaling, recruits MDSCs which hinder CD8⁺ T cells, subsequently promoting CRC. Blocking C5aR1 with antagonist significantly inhibited tumorigenesis, suggesting a novel preventive approach against CRC.

Creative Biolabs presents a tailored collection of C5AR1-focused services, which include interaction analyses and supplementary functional solutions. These offerings are meticulously crafted to support our esteemed clients in advancing their scientific research and clinical applications.

Reference

1. Ding, Peipei, et al. "C5aR1 is a master regulator in colorectal tumorigenesis via immune modulation." Theranostics 10.19 (2020): 8619. Distributed under Open Access license CC BY 4.0, without modification.