Background: Recently,attempts to treat disc degenerated disease(DDD)have turned to seeking answers from tissue engineering and regenerative medicine.A possible approach is to differentiate cells exhibiting plasticity such as mesenchymal stem cells(MSCs)and dermal fibroblasts(DFs)into the disc-like cells by exposing them to a biomimetic microenvironment in the disc.However,there is no systematic study in identifying and optimizing the biomimetic microenvironment,which is able to alter the phenotype and the fate of the plastic cells toward discogenic lineage.Methods: In this project,we attempt to reconstitute the biomimetic matrix microenvironment of the native nucleus pulposus(NP)tissue.Our approach was to culture nucleus pulposus cells(NPCs)within collagen microspheres whilst maintaining their phenotype and other characteristics,so that they would remodel the matrix microenvironment.Upon removal of the original NPCs,the reconstituted NPC-derived complex matrix was evaluated by proteomic analysis.Results: Previously we demonstrated that NPCs could maintain survival within the collagen microspheres and produce NP-like ECM such as glycosaminoglycan(GAG)and Type Ⅱ Collagen.According to the Mass Spectrometry(MS)results,an acellular matrix with partial retention of the ECM was obtained after decellularization.The decellularized microspheres were able to be repopulated with human MSCs and DFs.Conclusion: A complex composition of the reconstituted acellular NPC matrix niche was able to be partial preserved and this acellular matrix presented a potential system for inducing plastic cells differentiation into the NPC-like lineage.Ongoing efforts,include real-time PCR,will be use to assess the effects of the acellular matrices on plastic cells fate.