The lung changes functionally and structurally with aging. However, age-related effects on the extracellular matrix (ECM) and corresponding effects on lung cell behavior are not well understood. We hypothesized that ECM from aged animals would induce aging-related phenotypic changes in healthy inoculated cells. Decellularized whole organ scaffolds provide a powerful model for examining how ECM cues affect cell phenotype. The effects of age on ECM composition in both native and decellularized mouse lungs were assessed as was the effect of young vs old acellular ECM on human bronchial epithelial cells (hBECs) and lung fibroblasts (hLFs). Native aged (1 year) lungs demonstrated decreased expression of laminins α3 and α4, elastin and fibronectin, and elevated collagen, compared to young (3 week) lungs. Proteomic analyses of decellularized ECM demonstrated similar findings, and decellularized aged lung ECM contained less diversity in structural proteins compared to young ECM. When seeded in old ECM, hBECs and hLFs demonstrated lower gene expression of laminins α3 and α4, respectively, as compared to young ECM, paralleling the laminin deficiency of aged ECM. ECM changes appear to be important factors in potentiating agingrelated phenotypes and may provide clues to mechanisms that allow for aging-related lung diseases.
Bibliographical noteFunding Information:
This research was funded in part by the "Training in Lung Science" T32 training grant from the National Institutes of Health HL07741 (for LMG and BJS), National Institutes of Health R21 HL102570 (APM), National Institutes of Health R01 HL108627 (APM), National Institutes of Health R01HL107612 (for BJS), MSTP training grant NIH T32 GM008244 (for IA), UVM Lung Biology Training grant T32 National Institutes of Health HL076122 (DEW), National Institutes of Health RC4 HL106625 (DJW), National Institutes of Health R21HL108689 (DJW), and P20GM103449 (funding the Vermont Genomics Network). GalaxyP infrastructure is supported by National Science Foundation grant 1147079 (to UMN). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. We''d like to thank Dr. Peter Bitterman (UMN) for the gift of primary human lung fibroblasts and Emily Law (Dr. Rueben Harris lab, UMN) for providing us with aged BALB/c mice. The technical assistance of Amy Matson and Annechael Wood is greatly appreciated. GalaxyP is maintained by the Minnesota Supercomputing Institute at the University of Minnesota. We greatly appreciate assistance by the personnel at Center for Mass Spectrometry and Proteomics (CMSP)-especially Todd Markowski for sample preparation, LeeAnn Higgins for data acquisition and Timothy Griffin (PI) and Pratik Jagtap for providing the access to GalaxyP and its workflows. We would also like to thank Basa Zvarova at the University of Vermont for technical assistance with the standard mass spectrometry proteomic sample preparation.