title: TGF-beta1 regulation in hepatocyte-NIH3T3 co-culture is important for the enhanced hepatocyte function in 3D microenvironment.
abstract: Co-culture of hepatocytes or hepatocyte spheroids with the supporting NIH3T3 in a 3D microcapsule formed with a hybrid natural/synthetic matrix has led to enhanced hepatocyte functions. We investigated the mechanism of the functional enhancement in co-culture with respect to the contributions of soluble factors and direct cell-cell interactions. The conditioned media from the co-culture induced higher P450 cytochrome oxidase activity (indicated by EROD assay) in the microencapsulated hepatocytes than the conditioned media from the NIH3T3- or the hepatocytes-alone controls. Conditioned media from physically separated co-culture of hepatocytes-NIH3T3 by a membrane insert reduced the functional enhancement. Among the known stimulators of hepatocyte functions, TGF(beta)1 is primarily responsible for the stimulation of hepatocyte functions in this 3D co-culture since the removal of TGF(beta)1 by antibody depletion eliminated the functional enhancement and the reconstitution of TGF(beta)1 restored the functional enhancement. Activation of latent TGF(beta)1 in an extracellular environment were upregulated in co-culture with no observable increase in the TGF(beta)1 expression at transcriptional and translational levels. Our data led to an improved understanding of how co-culture enhances hepatocyte functions in vitro and pave the way for further innovations in liver tissue engineering, drug metabolism studies, and other applications that require functional hepatocytes cultured in vitro.
authors.affiliation: Department of Physiology, Block MD11 #04-01A, Clinical Research Centre, 10 Medical Drive, Singapore.
authors.forename: Ser-Mien
authors.initials: SM
authors.lastname: Chia
authors.forename: Pao-Chun
authors.initials: PC
authors.lastname: Lin
authors.forename: Hanry
authors.initials: H
authors.lastname: Yu
mesh_terms: D000818:Animals; D001709:Biotechnology / Q000379:methods*; D018920:Coculture Techniques; D017077:Culture Media, Conditioned; D019363:Cytochrome P-450 CYP1A1 / Q000032:analysis / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005109:Extracellular Matrix; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism*; D022781:Hepatocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D041681:NIH 3T3 Cells; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018874:Spheroids, Cellular / Q000378:metabolism; D013997:Time Factors; D016212:Transforming Growth Factor beta / Q000378:metabolism / Q000494:pharmacology*; D053773:Transforming Growth Factor beta1; D015854:Up-Regulation
chemical_list: D017077:Culture Media, Conditioned; C508961:Tgfb1 protein, mouse; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D019363:Cytochrome P-450 CYP1A1