Sannes, Philip L., Ph.D.
Professor of Cell Biology
Alumni Distinguished Undergraduate Professor
Ph.D.: The Ohio State University
Post-doctoral Training: Medical University of South Carolina, Division of Pathobiology
Phone: (919) 515-7656
Fax: (919) 515-4237
Epithelial responses to injury and mechanisms of repair in the mammalian lung; the relationships between components of extracellular matrices and soluble growth factors, transcription factors, and signaling molecules which modulate gene and protein expression; factors that influence proliferation and differentiation of adult lung epithelium.
Our work has focused on the mechanisms that influence the activities of a key cell in the adult pulmonary alveolus - the type II (AT2) epithelial cell – that plays a crucial role in repair processes following injury. In addition to producing surfactant, it acts as a facultative stem cell with the capacity to renew itself as well as serve as the precursor for AT1 cells, which cover over 90% of the alveolar surface area. We’ve developed data suggesting that the interaction of alveolar epithelial cells with specific components of the extracellular matrix (ECM) directly affects their ability to proliferate, to synthesize effector molecules vital to the repair process (such as cytokines and additional ECM components), and to effectively differentiate into type I (AT1) cells. We believe that one of the keys to repair following injury in the alveolar region is the distribution and nature of sulfated molecules that are either shed from cell surfaces in a soluble form or bound to fixed fibrillar components of ECM in insoluble forms, as found within the alveolar basement membrane (ABM). Specifically, the ABM microdomains associated with the AT2 cells are low in sulfate content, which promotes the biologic responsiveness of AT2 cells to critical growth factor signals (such as fibroblast growth factors -1 and -2) and normal proliferation - a major component of the repair process. The adjacent ABM microdomains of AT1 cells are high in sulfate content, which reduces the cell’s biologic responsiveness by slowing or impeding proliferation leading either to normal or, in some cases, aberrant repair.
Recent studies using discovery-based gene expression profile analysis were undertaken on freshly isolated human AT2 (hAT2) cells grown on extracellular matrix (ECM) substrata known to either support (type I collagen) or retard (Matrigel) the early transdifferentiation process into hAT1-like cells.Cell type-specific expression patterns analyzed by Illumina Human HT-12 BeadChip yielded over 300 genes that were up- or down-regulated. Candidate genes significantly induced or down-regulated during hAT2 transition to hAT1-like cells compared to non-transitioning hAT2 cells were identified. Major functional groups were also recognized, including those of signaling and cytoskeletal proteins as well as genes of unknown function. Expression of established signatures of hAT2 and hAT1 cells, such as surfactant proteins, caveolin-1, and channels and transporters, was confirmed (see figure below). Selected novel genes further validated by qRT-PCR, protein expression analysis, and/or cellular localization included SPOCK2, PLEKHO1, SPRED1, RAB11FIP1, PTRF/CAVIN-1 and RAP1GAP. These results further demonstrate the utility of genome-wide analysis to identify relevant, novel cell type-specific signatures of early ECM-regulated alveolar epithelial transdifferentiation processes in vitro.
Figure description: Paraffin-embedded normal human lung tissue sections were deparaffinized and immunofluorescence was performed for PTRF/CAVIN-1 (red) and caveolin-1 (green, left panel) or SP-C (green, right panel); DAPI (nuclei, blue). Caveolin and PTRF co-localize while PTRF and SP-C do not.
But these interconnected events can be influenced or interrupted by protracted injury or genetic variants, which result in activation of alternative or default pathways. This can involve shifts in epithelial phenotype which enable their breaching of the barrier of the basal lamina and invasion of the subepithelial interstitum. The result is fibroblast-like cell expansion and scar formation, as seen in many fibrogenic diseases of the lung. The factors that control this alternative pathway are poorly understood, but involve at least some of the known fibrogenic factors such as TGFβ, Wnt5A and Wnt7B. But the specific signaling events involved likely precede and go beyond those already known, and involve combinations ligands, signaling sequences, and target genes. Current studies focus on these poorly understood mechanisms.
Equipment and Techniques:
Molecular biology: RNA preparation and analysis, Northern blotting, qRT-PCR, cDNA cloning and characterization, inhibition and over-expression of selected gene targets by adenovirus and lentivirus gene transfer, gene arrays
Protein analysis: Western blotting, SDS-PAGE and native gel electrophoresis, biosynthetic labeling and analysis, radioactive and non-radioactive probes, CHiP assay.
Cell Biology and Microscopy: light and electron microscopy, immunohistochemistry, fluorescent probes, cytochemistry, isolation of primary lung cells and culture of cell lines.
Dush, M.K., A.L. McIver, M.A. Parr, D.D. Young, J. Fisher, D.R. Newman, P.L. Sannes, P.L., M.L. Hauck, A. Deiters, N. Nascone-Yoder. 2011. Heterotaxin: A TGF-β Signaling Inhibitor Identified in a Multi-Phenotype Profiling Screen in Xenopus Embryos. Chem.Biol. 18:252-263. PMID: 21338922; PMCID: 3050558
Meuten, T, A. Hickey, K. Franklin, B. Grossi, J. Tobias, H. Zhang, D.R. Newman, S. Jennings, M. Correa, P.L. Sannes. 2012. Wnt7B in fibroblastic foci of idiopathic pulmonary fibrosis. Resp. Res. Jul 28;13(1):62. PMID:22838404; PMCID:3479038
Zhang, H, D. R. Newman, and P. L. Sannes. 2012. HSulf-1 Inhibits ERK and AKT Signaling and Decreases Cell Viability in vitro in Human Lung Epithelial Cells. Respir Res. Aug 8;13(1):69. PMID:22873647; PMCID:PMC3514195.
Zhang, H, D. R. Newman, J. C. Bonner and P. L. Sannes. 2012. Over-expression of Human Endosulfatase-1 Exacerbates Cadmium-induced Injury to Transformed Human Lung Cells In Vitro. Tox.& Appl.Pharm. Nov 15;265(1):27-42. PMID:23000194; PMCID:PMC348997
Coffey, E, D.R. Newman, and P.L. Sannes. 2013. Expression of Fibroblast Growth Factor-9 in Normal Human Lung And Idiopathic Pulmonary Fibrosis. J. Histochem. Cytochem. 61(9):671-9. doi: 10.1369/0022155413497366. Epub 2013 Jun 24. PMID:23797050; PMCID: PMC3753889
* Featured cover photograph, J. Histochem. Cytochem September, 2013*
Johansson H.M., D.R.Newman, and P.L.Sannes. 2014. Whole-Genome Analysis of Temporal Gene Expression during Early Transdifferentiation of Human Lung Alveolar Epithelial Type 2 Cells In Vitro. PLoS ONE 9(4): e93413. doi:10.1371/ journal.pone.0093413. PMID:24690998; PMCID:PMC3972118
Sannes Lab Personnel:
Huiying Zhang, MS, Graduate Student
Donna Newman, PhD, Research Associate
Pictured below: Na Young Yi, Jody Khosla, Huiying Zhang, Helena Morales Johansson, Donna Newman, Dr. Phil Sannes