PI3K signaling is implicated in bradykinin-induced collective migration of ureteric bud (UB) cells

EDITH DEL VALLE GUAYTIMA; YAMILA ROMINA BRANDÁN; FRANCO EXEQUIEL MEGÍAS; NICOLÁS OCTAVIO FAVALE; NORMA B. STERIN-SPEZIALE; MARÍA GABRIELA MÁRQUEZ

Mar del Plata, Buenos Aires

Congreso; LI Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2015

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB)

Previously, we reported that bradykinin (BK) favors UB cell association to form migratory colonies through B2 receptor (B2R) activation. Now, we investigated the mechanisms involved in this phenomenon. We examined the expression of B2R in primary culture UB cells from seeded up to 48 hs by immunofluorescence. In early culture time, most of the cells expressed B2R and were DBA+ (an UB marker). When cultures acquired a higher cell compaction, denoted by E-cadherin immunostaining in adherens junctions, B2R expression decreased. Also, primary cultures of adult CD exhibited very few B2R+ cells. An increase in the protrusive activity denoted by extension of ruffling lamellipodium was observed after BK stimulation by time-lapse analysis. Pretreatment with LY294002 (PI3K inhibitor) impaired BK-induced cell-cell adhesion and membrane ruffles formation. Immunoblotting analysis did not show differences in Akt-P among untreated and BK-treated cells, with or without LY294002 pretreatment. In addition to Akt, Rac has been indicated as a downstream effector of PI3K. Activated Rac induces membrane ruffles formation to facilitate cell motility which is according with our results. Since PI3 kinase is associated with G-coupled receptors, our results suggest that PI3K signaling downstream B2R could be implicated in the induction of collective migration which occurs during UB branching morphogenesis.