Activation of the p38 and p42/p44 mitogen‐activated protein kinase families by the histamine H₁ receptor in DDT₁MF‐2 cells

Abstract

1 The mitogen-activated protein kinases (MAPKs) consist of the p42/p44 MAPKs and the stressactivated protein kinases, c-Jun N-terminal kinase (JNK) and p38 MAPK. In this study we have examined the e ect of histamine H 1 receptor activation on MAPK pathway activation in the smooth muscle cell line DDT 1 MF-2. 2 Histamine stimulated time and concentration-dependent increases in p42/p44 MAPK activation in DDT 1 MF-2 cells. Responses to histamine were inhibited by the histamine H 1 receptor antagonist mepyramine (K D 3.5 nM) and following pre-treatment with pertussis toxin (PTX; 57% inhibition). 3 Histamine-induced increases in p42/p44 MAPK activation were blocked by inhibitors of MAPK kinase 1 (PD 98059), tyrosine kinase (genistein and tyrphostin A47), phosphatidylinositol 3-kinase (wortmannin and LY 294002) and protein kinase C (Ro 31-8220; 10 mM; 41% inhibition). Inhibitors of Src tyrosine kinase (PP2) and the epidermal growth factor tyrosine kinase (AG1478) were without e ect. Removal of extracellular Ca 2+ , chelation of intracellular Ca 2+ with BAPTA and inhibition of focal adhesion assembly (cytochalasin D) had no signi®cant e ect on histamine-induced p42/p44 MAPK activation. 4 Histamine stimulated time and concentration-dependent increases in p38 MAPK activation in DDT 1 MF-2 cells but had no e ect on JNK activation. Histamine-induced p38 MAPK activation was inhibited by pertussis toxin (74% inhibition) and the p38 MAPK inhibitor SB 203580 (95% inhibition). 5 In summary, we have shown the histamine H 1 receptor activates p42/p44 MAPK and p38 MAPK signalling pathways in DDT 1 MF-2 smooth muscle cells. Interestingly, signalling to both pathways appears to involve histamine H 1 receptor coupling to G i /G o -proteins.

Stimulation of protein kinase B and p70 S6 kinase by the histamine H1 receptor in DDT1MF‐2 smooth muscle cells

“…We have recently reported that the PI-3K inhibitors, wortmannin and LY 294002, attenuated histamine H 1 receptor-induced p42/p44 MAPK activation in the smooth muscle cell line DDT 1 MF-2 (Robinson & Dickenson, 2001). The present study has therefore investigated whether the histamine H 1 receptor stimulates protein kinase B and p70 S6 kinase, both of which are downstream targets of PI-3K (Duronio et al, 1998;Toker, 2000).…”

“…These observations re¯ect the accepted coupling of the histamine H 1 receptor to phospholipase C activation via G q/11 -proteins (Hill et al, 1997). However, we have recently shown that histamine H 1 receptor-induced increases in p42/ p44 MAPK and p38 MAPK in DDT 1 MF-2 cells were partially sensitive to pertussis toxin suggesting coupling to members of the G i /G o -protein family (Robinson & Dickenson, 2001). Hence, in this study the role of G i /G o -proteins in histamine H 1 receptor-induced phosphorylation of PKB was determined in cells exposed to pertussis toxin (100 ng ml 71 ) for 16 h. As shown in Figure 3b, pertussis toxin pre-treatment virtually abolished histamine-induced increases in PKB phosphorylation.…”

“…The di ering e ect of wortmannin and LY 294002 on histamine H 1 receptor and EGF receptor-induced p70 S6 kinase phosphorylation (at Thr 421 /Ser 424 ) may re¯ect the role of PI-3K in the activation of p42/p44 MAPK by these two receptor types. Our previous studies have shown that stimulation of p42/p44 MAPK by the histamine H 1 receptor is dependent upon PI-3K activation in DDT 1 MF-2 cells (Robinson & Dickenson, 2001). In contrast, EGF triggers p42/p44 MAPK activation via a PI-3K-independent pathway (Hawes et al, 1996).…”

“…Inositol-1,4,5-trisphosphate triggers the release of calcium from intracellular stores, whereas diacylglycerol activates speci®c isoforms of protein kinase C. Downstream signalling events attributed to histamine H 1 receptor-mediated increases in intracellular calcium include the modulation of calcium/ calmodulin-dependent enzymes such as nitric oxide synthetase, phospholiapse A 2 and adenylyl cyclase (Leurs et al, 1995). In contrast, protein kinase C is known to be involved in histamine H 1 receptor stimulation of the p42/p44 mitogenactivated protein kinase (MAPK) pathway in DDT 1 MF-2 cells and activation of the c-fos promoter in transfected CHO cells (Megson et al, 2001;Robinson & Dickenson, 2001). …”

“…Our previous work has shown that inhibitors of phosphatidylinositol 3-kinase (PI-3K), wortmannin (Ui et al, 1995) and LY 294002 (Vlahos et al, 1994), markedly reduced p42/ p44 MAPK activation by histamine in DDT 1 MF-2 cells, suggesting that the histamine H 1 receptor activates PI-3K in these cells (Robinson & Dickenson, 2001). PI-3K is now known to regulate a variety of cellular events which involve the downstream activation of serine/threonine kinases such as protein kinase C isoforms, p70 S6 kinase and protein kinase B/Akt (Duronio et al, 1998;Toker, 2000).…”