MENLO PARK, Calif. & CAMBRIDGE, Mass.--(BUSINESS WIRE)--Protagonist Therapeutics, Inc. and Ironwood Pharmaceuticals, Inc. (NASDAQ: IRWD) today announced the expansion of their research collaboration. The collaboration, originally announced in January 2011, leverages Protagonist’s proprietary disulfide-rich peptide (DRP) technology platform and is aimed at providing Ironwood with novel peptides against targets for potential development in therapeutic areas with significant unmet medical needs.