How to use MEAN.js along with MySQL?

Question

I'm developing an intranet for a company under MEAN.js. I was wondering if there's a way to use MySQL along with MEAN.js and keep using MongoDB. Primarily I'll use mongo for heavy data, such as pdf's, videos, music, etc. I'll use MySQL for structured data such as users, profiles, statistics info, etc.

The main question is how to do it, and also would like some advices.

Searching i've found this example but it supplants MongoDB for MySQL, and i want to use both.