 Miragen Therapeutics NASDAQ:MGEN was downgraded by Zacks Investment Research from a buy rating to a hold rating in a research report issued to clients and investors on Wednesday, Zacks.com reports. According to Zacks, Miragen Therapeutics, Inc. is a biopharmaceutical company. It develops microRNA biology, oligonucleotide chemistry, drugs and therapies for cancer, pathologic fibrosis, neuro-inflammatory and ... 