I have no idea how shorting works on OTC stocks or how it's even done. With low volume and a very narrow trading range, I doubt there's much money to be made. I think the Market Makers are just trading back and forth to cover their positions.
There's no news because Nemus is working on financing/development deals so they can't do any press during that. Unlike other companies who put out the same news over and over and pay to pump the price.