Activated Leukocyte Cell Adhesion Molecule: A Novel Regulator of Allergic Inflammation in the Airways

Activated Leukocyte Cell Adhesion Molecule Regulates the Expression of Interleukin-33 in RSV Induced Airway Inflammation by Regulating MAPK Signaling Pathways

PURPOSE

The respiratory syncytial virus (RSV) is a common respiratory virus that causes acute lower respiratory tract infectious diseases, particularly in young children and older individuals. Activated leukocyte cell adhesion molecule (ALCAM) is a membrane glycoprotein expressed in various cell types, including epithelial cells, and is associated with inflammatory responses and various cancers. However, the precise role of ALCAM in RSV-induced airway inflammation remains unclear, and our study aimed to explore this gap in the literature.

METHODS

C57BL/6 wild-type, ALCAM knockout mice and airway epithelial cells were infected with RSV and the expression of ALCAM and inflammatory cytokines were measured. We also conducted further experiments using Anti-ALCAM antibody and recombinant ALCAM in airway epithelial cells.

RESULTS

The expression levels of ALCAM and inflammatory cytokines increased in both RSV-infected mice and airway epithelial cells. Interestingly, IL-33 expression was significantly reduced in ALCAM-knockdown cells compared to control cells following RSV infection. Anti-ALCAM antibody treatment also reduced IL-33 expression following RSV infection. Furthermore, the phosphorylation of ERK1/2, p38, and JNK was diminished in ALCAM-knockdown cells compared to control cells following RSV infection. Notably, in the control cells, inhibition of these pathways significantly decreased the expression of IL-33. In vivo study also confirmed a reduction in inflammation induced by RSV infection in ALCAM deficient mice compared to wild-type mice.

CONCLUSION

These findings demonstrate that ALCAM contributes to RSV-induced airway inflammation at least partly by influencing IL-33 expression through mitogen-activated protein kinase signaling pathways. These results suggest that targeting ALCAM could be a potential therapeutic strategy for alleviating IL-33-associated lung diseases.

Characterization of CD166 from Nile tilapia (Oreochromis niloticus) displays a broad pathogen recognition spectrum and involved the immune response to microbial aggression

CD166 is a member of the immunoglobulin superfamily of cell adhesion molecules, and its mediated adhesion plays a crucial role in different physiological and pathological phenomena, especially related to leukocyte extravasation, immune synapse stability, T cell activation and proliferation. In this study, CD166 was identified from Nile tilapia (Oreochromis niloticus, OnCD166). OnCD166 contains an open reading frame of 1671 bp that encodes a peptide of 556 amino acids, and contains five consecutive extracellular immunoglobulin domains. It's tissue distribution and expression patterns after S. agalactiae challenge were also investigated. OnCD166 is widely distributed in various tissues of healthy tilapia. After Streptococcus agalactiae challenge, OnCD166 expressions were significantly up-regulated in all tested immune tissues. Meanwhile, the recombinant OnCD166 (rOnCD166E) protein showed strong agglutinating activities against both Gram-negative bacteria and Gram-positive bacteria. Moreover, rOnCD166E could promote phagocytosis of macrophages. Taken together, our results illustrated that OnCD166 might as a receptor involved in the immune recognition and phagocytosis against invading pathogen, which play important roles in the immune responses of Nile tilapia against bacterial pathogens.

Elevated ALCAM Expression Associated with Endotypes and Postoperative Recurrence in Chronic Rhinosinusitis with Nasal Polyps

Background

Chronic rhinosinusitis with polyps (CRSwNP) is characterized by high heterogeneity and postoperative recurrence rate. This study aimed to explore the clinical significance of activated leukocyte cell adhesion molecule (ALCAM) in endotyping CRSwNP and predicting its recurrence.

Methods

We recruited 120 CRSwNP patients including 70 non-eosinophilic CRSwNP (neCRSwNP) and 50 eosinophilic CRSwNP (eCRSwNP) patients, and 40 healthy controls (HCs). Serum and tissue samples were collected. Serum ALCAM levels were detected by enzyme-linked immunosorbent assay (ELISA), and tissue ALCAM expression was assessed by reverse transcription-polymerase chain reaction (RT-PCR), Western blotting (WB) and immunohistochemistry (IHC). The predictive values of ALCAM expression for CRSwNP endotypes and postoperative recurrence were assessed.

Results

The serum levels of ALCAM were significantly increased in CRSwNP patients in comparison with HCs and were correlated with the peripheral eosinophil count, tissue eosinophil counts, and percentage. Multivariate analysis and receiver operating characteristic (ROC) curve highlighted that serum ALCAM levels were associated with CRSwNP endotypes. Tissue ALCAM expression was significantly enhanced in CRSwNP patients, especially in eCRSwNP patients. At the end of the study, 110 patients completed the follow-up schedule, 78 patients were categorized into the non-recurrent group, and the other 32 patients were included in the recurrent group. The serum ALCAM levels were elevated in the recurrent group compared with the non-recurrent group, and ALCAM expression in the tissue was significantly elevated. The ROC curve exhibited a high predictive ability of serum ALCAM in predicting postoperative recurrence. Logistic regression and Kaplan–Meier curves demonstrated that serum ALCAM was an independent risk factor for postoperative recurrence.

Conclusion

This is the first report suggesting that ALCAM expression was upregulated and associated with mucosal eosinophil infiltration and CRSwNP recurrence. Serum ALCAM could be a promising biomarker for distinguishing endotypes and predicting postoperative recurrence in CRwNP patients.

Activated leukocyte cell adhesion molecule as a biomarker for disease severity and efficacy of sublingual immunotherapy in allergic rhinitis

BACKGROUND

Activated leukocyte cell adhesion molecule (ALCAM) plays an important role in T cell activation and immune response, but the role of ALCAM in allergic rhinitis (AR) remains unclear. The objective of the current study was to validate serum ALCAM as a biomarker in assessing disease severity and predicting the efficacy of sublingual immunotherapy (SLIT) in AR patients.

METHODS

We recruited 40 healthy controls (HC group), 38 mild AR patients (MAR group) and 80 moderate-severe AR patients (MSAR group) in this study. Serum levels of ALCAM were determined by ELISA, and the association between ALCAM levels and disease severity was evaluated. In the MSAR group, 68 patients underwent and finished 3-years of SLIT, and were divided into effective group and ineffective group, the relationship between ALCAM levels and efficacy of SLIT was exampled.

RESULTS

ALCAM levels were elevated in the serum of AR patients in comparison with HC. Moreover, serum ALCAM concentrations were higher in MSAR group than in MAR group and HC group, and levels of ALCAM significantly correlated with AR total nasal symptom score (TNSS) (r = 0.330, P < 0.001), visual analogue scale (VAS) (r = 0.387, P < 0.001) and serum total IgE levels (r = 0.442, P < 0.001). In the effective group, the ALCAM levels were significantly lower than in the ineffective group. Receiver operating characteristic (ROC) curve exhibited good accuracy for predicting clinical efficacy of SLIT (area under the curve = 0.805, P < 0.001).

CONCLUSIONS

The serum ALCAM maybe a novel biomarker for assessing disease severity and predicting clinical efficacy of SLIT in AR patients.