Presence of functionally active protease‐activated receptors 1 and 2 in myenteric glia

Abstract

Protease-activated receptors (PARs) belong to the family of membrane receptors coupled to G-proteins; their presence is reported in a wide variety of cells. The object of this study was to demonstrate the presence of PAR-1 and PAR-2 in myenteric glia of the guinea pig, and to elucidate the cellular mechanisms that are triggered upon receptor activation.

Expression of a functional metabotropic glutamate receptor 5 on enteric glia is altered in states of inflammation

“…In neocortical cultures of rat astrocytes, thrombin decreases mGluR5 protein levels (Miller et al, 1996), effects which are mimicked by the synthetic peptide SFLLRN, implying that they are dependent on the activation of the protease activated receptor (PAR) 1 (Miller et al, 1996;Vergnolle, 2004). Cultured guinea pig enteric glia express functionally active PAR-1 and -2 (Garrido et al, 2002) and levels of proteases are elevated in colitis (Vergnolle, 2004). It is possible that glial PAR-1 stimulation could account for the changes in mGluR5 receptor expression that we have observed in the IL-10 2/2 mouse.…”

Thrombin and PAR-1-AP Increase Proinflammatory Cytokine Expression in C6 Cells1

“…PAR-1 is expressed on a number of cell types, including epithelium, endothelium, platelets, leukocytes, glial cells, astrocytes, and neurons [6,7]. The activation of PAR-1 leads to cell type-specific actions, including aggregation in platelets and enhancement of cytokine expression by leukocytes.…”

“…The activation of PAR-1 leads to cell type-specific actions, including aggregation in platelets and enhancement of cytokine expression by leukocytes. In a number of cell types, calcium release is an early consequence of PAR-1 activation [7,8].…”

Interleukin-1β and Interleukin-6 Stimulate Matrix Metalloproteinase-9 Secretion in Cultured Myenteric Glia

“…Zhang et al (2003) [27] showed that intercellular calcium wave propagation is a likely medium of communication for enteric glia. Moreover, myenteric glia have been shown to express functional protease-activated receptors (PARs), believed to participate in inflammation and in cellular responses to injury [11].…”

“…To confirm glial cell lineage we performed immunocytochemical staining for glial fibrillary acidic protein (GFAP) [2,11]. C6 glioma cells derived from a commercially available cell line were used as a positive control for glial cell lineage [12].…”