Jeff Cardwell was an aide to Pence in the Indiana governor's office before Pence picked him to head the state GOP in 2015.
Messer is a potential challenger to Democratic Sen. Joe Donnelly.
Vice President Mike Pence has been criticized for using an AOL account to conduct state business when he was governor.
Verma played a large role in shaping Indiana’s Medicaid expansion under the Affordable Care Act, known as the Healthy Indiana Plan or HIP 2.0.
A spokesman for Pence says he "retained records in full compliance with Indiana law."
Pence says he had an outside attorney review all of his private email records to identify any that referenced state business or related activities.
The Indianapolis Star reports that Pence communicated with advisers through his personal AOL account.
Pence will be the first vice president to deliver Notre Dame's commencement address.
Pence is scheduled to visit Frame USA, which sells American-made picture frames from its home base in a northern Cincinnati suburb.
The state supreme court hasn't yet decided whether it will consider the appeal.