د/ حنان عطية الامام في الحلقات النقاشية بكلية الصيدلة
تواصل كلية الصيدلة الحلقات النقاشية تحت رعاية الاستاذ الدكتور/ خالد ابو زيد محمد – عميد كلية الصيدلة و
ا.م.د/ ايناس علي ابراهيم – وكيل الكلية لشئون خدمة المجتمع و تنمية البيئة ، يوم الاحد الموافق 21 - 4 - 2019
و سوف تقدم د/ حنان الامام في تمام الساعة الثانية عشر في قاعة السيمنار بالمبني الجديد اخر ابحاثها تحت
“Role of Calcium – independent phospholipase A2 gamma in glomerular cell injury”
كما يختص البحث بالوصف التالي:
In experimental membranous nephropathy, complement C5b-9-induces glomerular epithelial cell (GEC) injury and proteinuria. The effects of C5b-9 are mediated via signaling pathways, including calcium-independent phospholipase A2γ (iPLA2γ), and mitogen-activated protein kinases (MAPKs), such as extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and p38. The iPLA2γ pathway is cytoprotective. The present study addresses the mechanisms of iPLA2γ activation. iPLA2γ activity was monitored by quantifying prostaglandin E2 (PGE2) production. In GEC, iPLA2γ localized at the endoplasmic reticulum and mitochondria. Complement-mediated production of PGE2 was amplified in GEC that overexpress iPLA2γ, compared with control cells, and was blocked by the iPLA2γ inhibitor, bromoenol lactone (BEL) in both iPLA2γ-overexpressing and control GEC. In GEC that overexpress iPLA2γ, complement-mediated PGE2 production was reduced by inhibitors of MAP/ERK kinase-1 (MEK1) and p38, but not JNK. In COS-1 cells that overexpress iPLA2γ and cyclooxygenase-1, PGE2 production was induced by co-expression of constitutively active MEK1 or MAPK-interacting kinase 1 (MNK1), as well as by stimulation with epidermal growth factor (EGF) + ionomycin. Complement- and EGF + ionomycin-stimulated iPLA2γ activity was attenuated by the S511A/S515A double mutation. Moreover, complement- and EGF + ionomycin enhanced phosphorylation of S511. Thus, complement-mediated activation of iPLA2γ is mediated via ERK and p38 pathways, and phosphorylation of S511 and/or S515 plays a key role in the catalytic activity and signaling of iPLA2γ. Defining the mechanisms by which complement activates iPLA2γ provides opportunities for development of novel therapeutic approaches to GEC injury and proteinuria.