CD200 in growing rat lungs: developmental expression and control by dexamethasone

Abstract

CD200 belongs to cell adhesion molecules of the immunoglobulin superfamily. It lacks intracellular signaling motifs and exerts immunosuppressive effect in various tissues. We have reported previously that CD200 is predominantly associated with the capillary network in the alveolar septum of adult rats. The alveolar endothelial cells express CD200, which is confined to their luminal cell membrane facing the blood-air barrier. Our present results show that lung CD200 protein increases gradually with advancing age, being maximally expressed in the early postnatal (P) period. CD200 protein expression, however, declines at P5 but increases again after P7, reaching the adult level at P21. In developing lungs in fetal and neonatal stages, double-immunofluorescence staining has confirmed intense CD200 immunoreactivity delineating the vascular profiles in the double layers of the alveolar capillaries; this staining becomes diffuse and patchy with time. Unlike in adult lungs, immunoelectron microscopy has revealed that CD200 expression in fetal and early postnatal lungs is localized over the entire luminal cell membrane and in the cytoplasm of the endothelia. CD200 expression is progressively redistributed to a specific luminal domain of alveolar endothelia during pulmonary microvascular maturation. In neonatal rats treated with dexamethasone, the amount of lung CD200 significantly increases and is also elevated with time. Upregulation of endothelial CD200 has further been confirmed in isolated pulmonary microvascular endothelial cells treated with dexamethasone. Thus, lung CD200 is developmentally regulated, possibly under hormonal influence.

Proteomic analysis of a murine model of lung hypoplasia induced by oligohydramnios

“…In the lung, CD200 is expressed on AEC2, Clara cells, and endothelial cells. CD200 has a dynamic expression in the developing lung and is associated with alveolar capillary development in rat lung 23 . Here, our results by proteomics analysis and further confirmed by western blot and IHC, revealed the downregulation of CD200 in a pulmonary hypoplasia mouse model.…”

“…CD200 has a dynamic expression in the developing lung and is associated with alveolar capillary development in rat lung. 23 Here, our results by proteomics analysis and further confirmed by western blot and IHC, revealed the downregulation of CD200 in a pulmonary hypoplasia mouse model. Furthermore, there is a reduction in lung angiogenesis, as previously demonstrated.…”

“…CD200 participates in autoimmune and allergic disorders, bone development, and reproductive biology 22 . Developmental regulation of CD200 in rat lung has been documented 23 suggestings CD200 has a potential role in OH‐induced pulmonary hypoplasia.…”

Modulation of recovery from neonatal hyperoxic lung injury by sex as a biological variable

“…10 C), which is a highly glycosylated cell surface protein. The CD200/CD200R immune ligand-receptor system decreases tissue resident macrophage activation [ [132] , [133] , [134] , [135] , [136] , [137] ]. The SELL (L-Selectin) signaling pathway was identified between the classical monocytes, neutrophils (immune cells) as sources and all the lung endothelial cells as targets.…”

The immunoregulatory protein CD200 as a potentially lucrative yet elusive target for cancer therapy

“…In the skeletal system, CD200 expression in osteoblasts is dependent on IL15RA signaling [ 70 ]. In the lung, both airway epithelial cell and capillary endothelial cell expression of CD200 is shown to be regulated by corticosteroids [ 71 – 72 ]. In hair follicle epithelial progenitors, CD200 expression is reported to be dependent on β1 integrin activation [ 73 ].…”