Open up and Opening up

Open up verb - Cause to open or to become open.

Opening up and open up are semantically related In some cases you can use "Opening up" instead a verb "Open up".

Open up and opening up are semantically related in begin topic. You can use "Open up" instead a verb "Opening up", if it concerns topics such as stab with pointed tool, bring up a topic, admit truth or reality of something, discharge a projectile.