8,330 questions
You can try something like this:
# Create the Outlook application object
$outlookApp = New-Object -ComObject Outlook.Application
# Get the VBA project
$vbaProject = $outlookApp.Project1 # or maybe ThisOutlookSession????
# Run the macro
$vbaProject.Application.Run("MySub")
Note: Not tested!
I'm not familiar with VBA/Outlook. I'm not sure of the name used as the project.