Exploring the evolving function of soluble intercellular adhesion molecule-1 in junction dynamics during spermatogenesis

Intercellular adhesion molecule-1 (ICAM-1) is a transmembrane glycoprotein expressed on immune, endothelial, and epithelial cells. Its ectodomain can be proteolytically cleaved to release a circulating soluble form called sICAM-1. Clinical studies demonstrate sICAM-1 is upregulated in various diseases and associated with disease severity. Research has identified sICAM-1 as a regulator of the blood-testis barrier (BTB) and spermatogenesis. Overexpression of sICAM-1 weakened the BTB in vitro and in vivo, downregulated junction proteins including N-cadherin, γ-catenin, and connexin 43, and caused germ cell loss. This contrasts with barrier-strengthening effects of membrane-bound ICAM-1. sICAM-1 may act as a molecular switch enabling germ cells to open BTB and Sertoli-germ cell adhesion for transport across the seminiferous epithelium. While the mechanism remains unclear, reduced SRC family kinase (SFK) signaling was observed following sICAM-1 overexpression. SRC promotes BTB protein endocytosis and degradation, influences cytoskeletal dynamics, and affects cell polarity. As sICAM-1 overexpression phenocopies SRC inhibition, SRC may operate downstream of sICAM-1 in regulating BTB dynamics and spermatogenesis. Investigating sICAM-1's structure-function regions and downstream targets will elucidate the molecular mechanisms of junction disruption. This knowledge could enable strategies targeting sICAM-1/SRC to modulate BTB permeability and treat male infertility or diseases involving endothelial/epithelial barrier dysfunction.

Serum Soluble Intercellular Adhesion Molecule-1 (sICAM-1): A Novel Potential Biomarker in Severe Acne Vulgaris

Background

Acne vulgaris (AV) is a chronic inflammatory disorder. Intercellular adhesion molecule-1 (ICAM-1) is a vital adhesion molecule mediating cellular adhesion during the inflammatory process.

Aims and Objectives

To evaluate serum soluble intercellular adhesion molecule-1 (sICAM-1) level in AV patients as an attempt to elucidate its role in acne pathogenesis and to relate with studied clinical parameters.

Materials and Methods

Serum sICAM-1 level was measured using ELISA technique in 60 patients and 60 controls.

Results

Serum sICAM-1 level was significantly elevated in studied patients than controls (P < 0.001). Additionally, its level increased significantly with increased acne severity (P < 0.001) but not in patients with post acne scars (P > 0.05).

Conclusion

Serum sICAM-1 could be a marker for acne etiopathogenesis. Furthermore, it might be considered as a predictor for disease severity.

Soluble ICAM-1 a Pivotal Communicator between Tumors and Macrophages, Promotes Mesenchymal Shift of Glioblastoma

Despite aggressive clinical treatment, recurrence of glioblastoma multiforme (GBM) is unavoidable, and the clinical outcome is still poor. A convincing explanation is the phenotypic transition of GBM cells upon aggressive treatment such as radiotherapy. However, the microenvironmental factors contributing to GBM recurrence after treatment remain unexplored. Here, it is shown that radiation-treated GBM cells produce soluble intercellular adhesion molecule-1 (sICAM-1) which stimulates the infiltration of macrophages, consequently enriching the tumor microenvironment with inflammatory macrophages. Acting as a paracrine factor, tumor-derived sICAM-1 induces macrophages to secrete wingless-type MMTV integration site family, member 3A (WNT3A), which promotes a mesenchymal shift of GBM cells. In addition, blockade of either sICAM-1 or WNT3A diminishes the harmful effect of radiation on tumor progression. Collectively, the findings indicate that cellular crosstalk between GBM and macrophage through sICAM-1-WNT3A oncogenic route is involved in the mesenchymal shift of GBM cells after radiation, and suggest that radiotherapy combined with sICAM-1 targeted inhibition would improve the clinical outcome of GBM patients.