Chronic obstructive pulmonary disease (
COPD) has become the third-leading cause of death worldwide, which is a severe economic burden to the healthcare system.
Chronic bronchitis is the most common condition that contributes to
COPD, both locally and systemically. Neutrophilic
inflammation predominates in the
COPD airway wall and lumen. Logically, repression of neutrophilia is an essential fashion to
COPD treatment. However, currently available anti-neutrophilic
therapies provide little benefit in
COPD patients and may have serious side effects. Thus, there is an urgent need to explore an effective and safe anti-neutrophilic approach that might delay progression of the disease.
Sialic acid-binding
immunoglobulin-like
lectin (Siglec)-9 is a member of the
Siglec cell
surface immunoglobulin family. It is noteworthy that Siglec-9 is highly expressed on human neutrophils and monocytes.
Ligation of Siglec-9 by chemical compounds or synthetic
ligands induced apoptosis and autophagic-like cell death in human neutrophils. Furthermore, administration of antibody to
Siglec-E, mouse functional ortholog of Siglec-9, restrained recruitment and activation of neutrophils in mouse models of airway
inflammation in vivo. Given the critical role that neutrophils play in
chronic bronchitis and
emphysema, targeting Siglec-9 could be beneficial for the treatment of
COPD,
asthma,
fibrosis, and related chronic inflammatory
lung diseases.