Platelet aging demystified
doi:10.1038/nindia.2013.49 Published online 1 April 2013
How do blood platelets, with an average life span of 10-12 days, age and die? New research shows that these highly sensitive cells, which help stop bleeding at an injury site, actually age because of the over-activity of a death-inducing protein called Bax1.
Apart from helping blood clot, platelets have also been reported to have a hand in triggering the onset of conditions like heart attacks and strokes. Human blood platelets have an average age of about 10 days days after which macrophages clear them out of the blood stream. However, the mechanism behind their aging and death had not been studied till now.
Researchers have now shown that during early days in the life of a platelet cell, this Bax protein is degraded by a proteasome complex. As the platelet's life increases, Bax escapes degradation and eventually leads to the death of the platelet. Lead researcher Debabrata Dash says the life span of a platelet is determined by the activity of an 'internal clock' influenced by the activity of the proteasome complex.
"We elucidated the molecular players that regulate the platelet life span and restrict it to 10-12 days," Dash told Nature India.
The researchers experimented on mice to find that when they inhibited proteasome activity, it resulted in significant decrease in the number of platelets (thrombocytopenia) — the average platelet half-life went down from 66 hours to 37 hours.
The findings will help in the management of bleeding disorders and in anti-cancer therapy in which proteasome activities are therapeutically targeted, Dash says.