Manage, in charge of symbols (5)
I believe the answer is:
'symbols' is the definition.
(I have seen 'mysterious symbols' mean 'runic' so perhaps 'symbols' could also mean 'runic')
'manage in charge' is the wordplay.
'manage' becomes 'run' (both can mean to organise).
'in charge' becomes 'ic' (abbreviation for 'in charge').
'of' is the link.
(Other definitions for runic that I've seen before include "Of old magic symbols" , "Relating to old Germanic alphabet" , "Inscribed with ancient symbols" , "of collection of old letters" , "character hard to interpret" .)