Title:Eryptosis: Ally or Enemy
Volume: 24
Issue: 9
关键词:
黑色素沉着,疟疾,贫血症,β-地中海贫血,细胞溶质的钙离子,糖尿病
摘要: Prior to senescence, erythrocytes may experience injury, which compromises their
integrity and thus triggers suicidal erythrocyte death or eryptosis. This mechanism is characterised
by cell shrinkage, cell membrane blebbing, and cell membrane phospholipid scrambling
after phosphatidylserine exposure on the cell surface that is identified by macrophages, which
engulf and degrade the eryptotic cells. The term eryptosis also includes typical mechanisms,
which contribute to the triggering of this process, such as oxidative stress, Ca2+ entry with an
increase in cytosolic Ca2+ activity ([Ca ]i) and the activation of p38 kinase, which is a kinase
expressed in human erythrocytes and activated after hyperosmotic shock. Enhanced eryptosis
has been observed in several clinical conditions such as diabetes, renal insufficiency, haemolytic
uremic syndrome, sepsis, mycoplasma infection, malaria, iron deficiency, sickle cell
anaemia, beta-thalassemia, glucose-6-phosphate dehydrogenase-(G6PD) deficiency, hereditary
spherocytosis, paroxysmal nocturnal haemoglobinuria, Wilson's disease, myelodysplastic syndrome,
and phosphate depletion. Therefore, eryptosis may be considered as a useful mechanism
of removal of defective erythrocytes to prevent haemolysis. Moreover, the clearance of
infected erythrocytes in diseases such as malaria may counteract parasitemia. Indeed it is
known that sickle-cell trait, beta-thalassemia trait, glucose-6-phosphate dehydrogenase
(G6PD)- deficiency and iron deficiency confer some protection against a severe course of malaria.
Importantly, strategies to control Plasmodium infection by inducing eryptosis are not
expected to generate resistance of the pathogen, as the proteins involved in suicidal death of
the host cell are not encoded by the pathogen and thus cannot be modified by mutations of its
genes. However, excessive eryptosis could compromise microcirculation and lead to anemia.