Annexin 1 (ANXA1), a 37kDa protein, is a mediator of glucocorticoid action in the neuroendocrine and host-defence systems and is also strongly implicated in the processes regulating the cell cycle (John et al., 2004) . The mechanism of ANXA1 action is poorly understood and its potential to influence gene expression has scarcely been addressed. Accordingly, we have used RaSH to examine the effects of human recombinant ANXA1 (hrANXA1) and an N-terminal ANXA1 peptide (ANXA1_Ac2-26) on gene expression in cell lines of epithelial and putative microglial origin. Human larynx epithelial (Hep 2) and human pituitary folliculostellate (PDFS) cell lines were plated at concentration of 10⁶/plate and stimulated for 72 hours with either hrANXA1 (100 nM) or ANXA1 _Ac2-26( 2 µM ). Total RNA was isolated and processed for RaSH analysis exactly as described by Kang et al. (2001) . The sequences of differentially expressed genes were blasted with the nucleotide Bank (Gen Bank) and the observed alterations in gene expression were verified by RT-PCR and western blot analysis. Three genes showed strong differential expression after treatment with hrANXA1 and/or ANXA1_Ac2-26. These were (a) GPR2, a seven transmembrane receptor for chemokine CCL27, which is involved in T-cell mediated inflammation in the skin and in neuroinflammation, (b) FARSL, a tumour-selective regulator of cell differentiation and (c) T2BP, a cell survival signaling protein. In both cell lines the expression of GPR2 was up-regulated by hrANXA1 and ANXA1_Ac2-26 while that of FARSL was reduced. By contrast, while ANXA1_Ac2-26 reduced the expression of T2BP, hrANXA1 was without effect (Table 1). Since ANXA1 and related peptides are potential ligands for members of the formyl peptide receptor (FPR) family and our cell lines both express FPR and FPRL1, we also examined the effects of two selective ligands of these receptors, fMLP (100nM) and LXA4 (2 µM) respectively, on GPR2, FARSL and T2BP expression. The responses to fMLP were qualitatively similar to those of hrANXA1 and ANXA1_Ac2-26. However, in the concentration tested, LXA4 was inert (Table1).

Table .1:Effects of hrANXA1, ANXA1_Ac2-26, fMLP and LXA4 vs. control on the expression of mRNA for GPR2, FARSL and T2BP in PDFS cells (n=3 experiments).

	hrANXA1	ANXA1Ac2-26	fMLP	LXA4
GPR2
FARSL
T2BP

The results provide new evidence that ANXA1 influences gene expression. They also show a dissociation between the activities of hrANXA1 and ANXA1_Ac2-26 in this regard, as has been described previously in other systems (John et al., 2004), and indicate that the actions of ANXA1_Ac2-26, but not hrANXA1, in the cell lines we employed areakin to those of the FPR ligand, fMLP.

John, C. D. et al. (2004). Trends Endocrinol Metab 15, 103-109
Kang, D. et al., Gene 267, 233-242

We thank the Wellcome Trust for generous financial support. FRL is a FAPESP and CNPQ PhD fellow