I hope this solves the problem.
$text = "<a class='userpro-init-chat' href='#' data-chat_with='". get_the_author_meta('ID')."' data-chat_from= '".get_current_user_id()."' >Reply to this ad!</a>";
echo do_shortcode('[userpro_private]'.$text.'[/userpro_private]');