Making one’s Messenger topic a du‘aa’ (supplication) or word of wisdom

There are "topics" for Messenger of different types, including some
that are called Islamic topics. I chose one of these topics for my
e-mail. Is it permissible for me to do that? Please note that chat or
writing begins with this Islamic topic that I chose.
Praise be to Allah.
There is nothing wrong with using Messenger topics and choosing useful
words, or beneficial supplications, or goodlines of poetry. That will
serve as a reminder to one's friends, and will prompt and remind them
to do good and obey Allah.
And Allah knows best.