An Immunocytochemical and In Situ Hybridization Analysis of Annexin 1 Expression in Rat Mast Cells: Modulation by Inflammation and Dexamethasone

Abstract

SUMMARY:The presence and localization of the anti-inflammatory protein annexin 1 (also known as lipocortin 1) in perivenular rat mast cells was investigated here. Using the rat mesenteric microvascular bed and a combination of morphologic techniques ranging from immunofluorescence to electron microscopy analyses, we detected the presence of annexin 1 in discrete intracellular sites, both in the nucleus and in the cytoplasm. In resting mast cells, most of the protein pool (approximately 80% of the cytosolic portion) was localized to cytoplasmic granules. In agreement with other cell types, treatment of rats with dexamethasone (0.2 mg/kg, ip) increased annexin 1 expression in mast cells, inducing a remarkable appearance of clusters of protein immunoreactivity. This effect was most likely the result of de novo protein synthesis as determined by an increase in mRNA seen by in situ hybridization. Triggering an ongoing experimental inflammatory response (0.3 mg of carrageenin, ip) increased annexin 1 mRNA and protein levels. In conclusion, we report for the first time the localization of annexin 1 in connective tissue mast cells, and its susceptibility not only to glucocorticoid hormone treatment, but also to an experimental acute inflammatory response.

A Novel Effect for Annexin 1-Derived Peptide Ac2-26: Reduction of Allergic Inflammation in the Rat

“…With particular reference to allergen-induced pleurisy in rats, activation of mast cells seems to be a primary event that may lead to both plasma leakage and leukocyte infiltration (Diaz et al, 1996;Lima et al, 1996). It is noteworthy that annexin 1 can be up-regulated by distinct stimuli in rat mast cells (Tasaka et al, 1994;Oliani et al, 2000) and correlated with down-regulation of compound 48/80-induced histamine release (Tasaka et al, 1994). In our study, local treatment with the peptide Ac2-26 attenuated ovalbumin-evoked mast cell degranulation in the rat pleural space, a finding that was also substantiated in in vitro settings.…”

Annexin 1: Differential expression in tumor and mast cells in human larynx cancer

“…Mast cells can be beneficial or detrimental to the tumor depending on the tumor stroma microenvironment altering its secretory process. 25 A number of studies have provided evidence that mast cells express the anti-inflammatory protein ANXA1 18,19,42 and this protein has been implicated in playing an important role in tumor development, directly or indirectly, and could be a diagnostic marker for certain types of tumors. 7 Our results have demonstrated the intracellular localization and disposition of human mast cell ANXA1 by ultrastructural immunocytochemical analysis in laryngeal tissues (tumor, peritumoral and control tissues) obtained from the same patient.…”

“…Previous studies demonstrated that increased ANXA1 expression in rat mast cells after dexamethasone treatment might be one of the potential mechanisms by which glucocorticoids inhibit the mast cells degranulation. 18,42 Also local administration of the ANXA1 N-terminal peptide inhibits mast cell degranulation in rats inflamed by infection of ovalbumin into the pleural cavity. 19 The increase in ANXA1 expression observed in mast cells in the tumor and peritumoral region compared to control tissue, suggests that the endogenous protein may act as a feedback response in the modulation of mediators release.…”

“…18 Ultrathin sections (70 nm) of laryngeal tissues (tumor, peritumoral and control) and Hep-2 cells were prepared and incubated at room temperature with 0.1 M phosphate buffer containing 5% egg albumin (PBEA) for 30 min. The sections were then incubated for 2 hr with a polyclonal antibody anti-ANXA1 named LCPS1, a sheep polyclonal antibody raised against the N-terminal peptide of human ANXA1 (peptide Ac2-26), diluted 1:200 in 1% PBEA.…”

“…8 ANXA1 also has been reported in inflammatory cells, particularly in mast cells involved in the inflammatory responses. 18,19 Mast cells have been reported in various types of the cancer such as breast, 20 skin, 21 liver 22 and gastric. 23 These cells accumulate at sites of tumor growth in response to numerous chemoattractants.…”