Protease-Activated Receptor-2 Modulates Protease-Activated Receptor-1–Driven Neointimal Hyperplasia

Abstract

Objective Emerging evidence suggests that protease-activated receptors-1 and 2 (PAR1 and PAR2) can signal together in response to proteases found in the rapidly changing microenvironment of damaged blood vessels. However, it is unknown whether PAR1 and PAR2 promote or mitigate the hyperplastic response to arterial injury. Using cell-penetrating PAR1 pepducins and mice-deficient in PAR1 or PAR2, we set out to determine the respective contributions of the receptors to hyperplasia and phenotypic modulation of smooth muscle cells (SMCs) in response to arterial injury. Methods and Results SMCs were strongly activated by PAR1 stimulation as evidenced by increased mitogenesis, mitochondrial activity, and calcium mobilization. The effects of chronic PAR1 stimulation following vascular injury were studied by performing carotid artery ligations in mice treated with PAR1 agonist pepducin, P1pal-13. Histological analysis revealed that PAR1 stimulation caused striking hyperplasia which was ablated in PAR1-/-, and surprisingly in PAR2-/- mice. P1pal-13 treatment yielded an expression pattern consistent with a de-differentiated phenotype in carotid artery SMCs. Detection of PAR1-PAR2 complexes provided an explanation for the hyperplastic effects of the PAR1 agonist requiring the presence of both receptors. Conclusions We conclude that PAR2 regulates the PAR1 hyperplastic response to arterial injury leading to stenosis.

Factor VII activating protease (FSAP) regulates the expression of inflammatory genes in vascular smooth muscle and endothelial cells

“…The focus of our studies was to characterize the changes in gene expression Various studies have shown that PAR1 can trans-activate PAR2 [115][116][117][118]149 .We examined the possible role of receptor dimerization between PAR1 and PAR2 by over-expressing SEAP-PAR1 and PAR2-Flag in HEK293T or A549 cells but did not find any evidence that this leads to a major change in either the activation or cleavage of these receptors (data not shown). Similarly, some Gla domaincontaining proteases such as APC and FXa need the co-receptor, EPCR to facilitate PAR activation 98,122 .…”

Transactivation of the PAR1-PAR2 Heterodimer by Thrombin Elicits β-Arrestin-mediated Endosomal Signaling

“…Interestingly, Kaneider et al (16) showed that PAR2 associates with PAR1 in endothelial cells during late stages of sepsis and switches thrombin signaling from barrier-disruptive to barrier-protective. In other work, PAR2 expression was shown to be necessary for PAR1-induced hyperplasia in vascular smooth muscle cells (17). The ability of PAR1 to transactivate PAR2 would necessitate that the two receptors be in close proximity, likely in the form of a heterodimer.…”

“…The ability of PAR1 to transactivate PAR2 would necessitate that the two receptors be in close proximity, likely in the form of a heterodimer. Two previous studies have suggested that PAR1 and PAR2 associate (16,17). However, the mechanisms that govern PAR1-PAR2 heterodimer formation, trafficking, and signaling have not been investigated.…”

Prospects for use of peptides and their derivatives, structurally corresponding to the G protein-coupled receptors, in medicine

“…При лечении им мышей на протяжении 21 дня в дозе 2,5 мг/кг наблюдалась сильно выраженная гиперплазия неоинтимы в повреждённой сонной артерии [30]. Область неоинтимы при обработке пепдуцином P1pal-13 увеличивалась в 13 раз в сравнении с контролем, что приводило к полному стенозу сонной артерии.…”

“…Тот факт, что у мышей, нокаутных по генам, кодирующим PAR1-рецептор, проангиогенное действие пепдуцина не выявлялось, указывает на определяющую роль гомологичного ему рецептора в молекулярных механизмах действия пепдуцина. Гиперпластический эффект пепдуцина P1pal-13 также отсутствовал у мышей, нокаутных по гену PAR2-рецептора, что свидетельствует о необходимости образования гетеродимерных PAR1-PAR2 комплексов для функциональной активности PAR1-рецептора [30]. Активация PAR1-рецептора металло-протеиназой-1, которая выполняет функции PAR1-агониста, в фолликулярных клетках яичников приводила к усилению секреции соседними эндотелиальными клетками ангиогенных хемокинов, в первую очередь, интерлейкина-8 и хемокина CXCL1/GRO-a, и к повышению экспрессии чувствительных к ним хемокиновых рецепторов CXCR1 и CXCR2 [31].…”