Activation of beta 1 integrin fibronectin receptors on HL60 cells after granulocytic differentiation

Abstract

Phorbol esters upregulate the functional affinity of beta 1 integrin receptors for fibronectin on human neutrophils and other leukocytes. We investigated the ability of phorbol myristate acetate (PMA) to stimulate the human promyelocytic cell line HL-60 to adhere to fibronectin, either in its undifferentiated state (HL60) or after dimethylsulfoxide-induced differentiation along the granulocytic pathway (dHL60). PMA stimulated little adherence of undifferentiated HL60 to fibronectin or to the 120-kD chymotryptic cell-binding domain (CBD) of fibronectin. In contrast, PMA stimulated dHL60 cells to rapidly adhere to both fibronectin- and to CBD-coated plastic. PMA- stimulated dHL60 adherence to fibronectin was largely mediated by both alpha 4 beta 1 and alpha 5 beta 1, whereas PMA-stimulated dHL60 adherence to CBD was largely mediated by alpha 5 beta 1. There was little contribution from beta 2 integrins to PMA-stimulated dHL60 adherence to fibronectin or CBD. The inability of undifferentiated HL60 to adhere to fibronectin and CBD did not result from lack of expression of alpha 4 beta 1 or alpha 5 beta 1 because HL60 and dHL60 express similar amounts of both alpha 4 beta 1 and alpha 5 beta 1 on their surface. In addition, 1 mmol/L Mn2+ induced similar amounts of alpha 5 beta 1-dependent adherence of both HL60 and dHL60, showing that alpha 5 beta 1 on undifferentiated HL60 is capable of binding to its ligand. These data suggest that activation of protein kinase C cannot functionally upregulate these beta 1 integrins on undifferentiated HL60 cells. The development of PMA-stimulated beta 1-dependent adherence after granulocytic differentiation of HL60 cells suggests that the differentiated HL60 cell is a useful model for investigating functional coupling of protein kinase C to beta 1 integrin in myeloid cells.

Cytokines increase human hemopoietic cell adhesiveness by activation of very late antigen (VLA)-4 and VLA-5 integrins.

“…This is particularly well documented for the platelet integrin o/iib/33 (34)(35)(36), fit integrins, such as VLA-6 (37,38), and 132 integrins, such as LFA-1 (39). Agonists which stimulate/31 integrin-mediated adhesiveness on hemopoietic and immune cells include activators of protein kinase C, such as PMA (9,40), cross-linking of antibodies specific for CD31 (24,41), the T cell receptor, CD7, CD28 (42), and certain activating anti-CD29 mAb (18,(43)(44)(45).…”

Neutrophil differentiated HL‐60 cells model Mac‐1 (CD11b/CD18)‐independent neutrophil transepithelial migration

“…For example, the absence of secondary granules will exclude a number of adhesion molecules as potential candidates in Mac-1-independent migration. 40 Mac-1 expression on DMSO-differentiated HL-60 cells has been well documented 26,[41][42][43] while Mac-1 expression on dbcAMP-differenti-ated HL-60 cells has not been well studied. Although some investigators have demonstrated positive staining for CD11b on dbcAMP-differentiated cells, the level of its expression did not differ from the level on undifferentiated HL-60 cells.…”

Selective upregulation of a functional β7 integrin on differentiating eosinophils

“…Additional adhesion pathways, including the α 5 integrin and the CD11/CD18 complex, could explain the observed residual adhesion of induced clone 15 cells to fibronectin. Indeed, we noted that the majority of induced cells expressed the α 5 integrin (56–58) concomitant with an upregulation of complement receptor type 3 (CR3 or CD11b/CD18).…”