Involvement of the Constitutive Photomorphogenesis 9 Signalosome Subunit 5 With Programmed Cell Death Protein 1 Ligand in Asthma

PURPOSE: The constitutive photomorphogenesis 9 signalosome (CSN) is a highly conserved protein complex comprised of eight subunits, each of which play crucial roles in diverse cellular processes, such as signal transduction, gene transcription, angiogenesis, and cell proliferation.

In the context of asthma, a potential emerging target is the programmed death-ligand 1 (PD-L1)-mediated pathway, which serves as a significant immune checkpoint inhibitor in this condition.

However, the precise involvement of CSN subunit 5 (CSN5) in bronchial asthma and the interplay between CSN5 and PD-L1 in asthma remain poorly understood.

METHODS: The potential association between CSN5 and bronchial asthma was explored in a mouse model of ovalbumin (OVA)-induced asthma.

Samples were obtained from human lung microvascular endothelial cell (HMVEC-L) treated with Dermatophagoides pteronyssinus (Der p 1) and CSN5 small interfering RNA.

The expression of nuclear factor (NF)-κB, IκBα, inhibitor of κB kinase β (IKKβ), PD-L1, and CSN5 was assessed.

Additionally, plasma CSN5 levels in asthma patients, both in stable and exacerbated states, were examined.

RESULTS: Plasma levels of CSN5 were elevated in patients with exacerbated asthma (n = 19) compared to both healthy controls (n = 10) and patients with stable asthma (n = 19).

The CSN5 level demonstrated a correlation with lung function in individuals with asthma.

Silencing CSN5 in HMVEC-L led to a reduction in NF-κB protein levels at 4 hours and PD-L1 levels at 4, 8, and 24 hours after Der p 1 treatment.

In OVA-sensitized/challenged mice, goblet cell hyperplasia, lung fibrosis, and the levels of CSN5, PD-L1, interleukin-13, interferon-γ, phospho (p)-NF-κB, p-IκBα, and p-IKKβ proteins increased at 33 and 80 days compared to control mice.

However, these changes were mitigated by treatment with a PD-L1 inhibitor.

CONCLUSIONS: These findings suggest that CSN5, along with PD-L1, could serve as a promising target for the treatment of asthma.