Douglas S. Darling, Ph. D.

Director, UofL Oral Biology Graduate Program


Phone: 502-852-5508
E-mail: douglas.darling@louisville.edu

Department of Oral Health and Rehabilitation,
Birth Defects Center, Center for Genetics and Molecular Medicine, and
Center for Environmental Genetics and Integrative Biology

 

 

Additional Appointments:

  • Professor, Department of Oral Immunology and Infectious Diseases, School of Dentistry
  • Department of Biochemistry & Molecular Genetics, School of Medicine
  • Center for Genetics and Molecular Medicine
  • Institute for Molecular Diversity & Drug Design (IMD3)

Education:

  • George Washington University, Washington, D.C., B.S., 1977
  • University of Washington, Seattle, WA, Ph. D., 1983
  • University of Chicago Medical School, Chicago, IL, Postdoctoral, 1983-87
  • Harvard University + Howard Hughes Medical Institute, Boston, MA, Postdoctoral, 1987-92

Laboratory Team Members:

  • Dr. Venkatesh Srirangapatnam;  Postdoc
  • Anne Carenbauer; Technician Senior
  • Melissa Metzler; PhD Student (Biochemistry)
  • Diana Blau;  Masters in Oral Biology Student
  • Sarah Perez; Masters in Oral Biology Student
  • Ian Pyle; Masters in Oral Biology Student

Research Focus:

We are studying the molecular basis for trafficking of secreted proteins within the cell during regulated secretion.  Secretory proteins synthesized in the major salivary glands, including the parotid glands, are primarily stored in dense-core secretory granules and released in response to external stimuli (regulated or stimulated secretion). Parotid salivary proteins are secreted apically, primarily by the regulated secretory pathway. Proteins that are not targeted or retained in secretory granules are secreted constitutively (including basolateral secretion). Trafficking of cargo proteins must direct them into the correct pathway.  Understanding how sorting occurs in salivary glands would contribute to the correct targeting of therapeutic transgenes.  To study the molecular basis for trafficking, we use a proteomics approach to define proteins in the secretory granule membrane, and several protein-interaction approaches.  We use a novel model for sorting of salivary proteins in which Parotid Secretory Protein (PSP) binds the membrane at phosphatidylinositol bisphosphate. 

Loss of salivary gland function is clinically important. Understanding the differentiation of salivary cells is a necessary step to enable the restoration of diseased or destroyed parotid salivary tissue. Computer modeling of biological systems is a potentially powerful approach to discriminate key regulatory steps.  We are using gene expression arrays of differentiating salivary glands to identify networks that cause terminal differentiation.  The gene networks are being incorporated into differential equation models of development.  These computer models are expected to have the capacity to test the relative importance of specific pathways within the network, allowing further validation by laboratory work.

Separately, our laboratory is interested in the regulation of gene transcription in eucaryotic cells. We are investigating the molecular mechanism of action of the zfh family of transcription factors.  We had isolated cDNA and genomic clones of the Zinc Finger Homeodomain Enhancer-binding Protein (Zfhep, Zfhx1a, ZEB1) gene.  ZEB1 is essential for life as well as T-cell development, craniofacial development, and skeletal patterning.  ZEB1 is a SMAD-binding protein, and therefore is part of the TGFbeta family signaling mechanism.  Current projects investigate the role of ZEB and related genes in early development, and the molecular interactions that underlie those roles.  We focus on development of the eye, which has specific defects in ZEB1-mutant mice that mimic birth defects in some human babies.  In addition, we are studying the molecular basis for cleft palate in ZEB1 knock-out mice. 

Selected Publications:

  • Llorens MC, Lorenzatti G, Cavallo NL, Vaglienti MV, Perrone AP, Carenbauer AL, Darling DS, Cabanillas AM. Phosphorylation Regulates Functions of ZEB1 Transcription Factor. J Cell Physiol. 2016 Oct;231(10):2205-17. PubMed PMID: 26868487.
  • Sztukowska MN, Ojo A, Ahmed S, Carenbauer AL, Wang Q, Shumway B, Jenkinson HF, Wang H, Darling DS, Lamont RJ. Porphyromonas gingivalis initiates a mesenchymal-like transition through ZEB1 in gingival epithelial cells. Cell Microbiol. 2016 Jun;18(6):844-58. PubMed PMID: 26639759.
  • Sánchez-Tilló E, de Barrios O, Valls E, Darling DS, Castells A, et al. ZEB1 and TCF4 reciprocally modulate their transcriptional activities to regulate Wnt target gene expression. Oncogene. 2015 Nov 12;34(46):5760-70. PubMed PMID: 26387539.
  • Metzler MA, Appana S, Brock GN, Darling DS. Use of multiple time points to model parotid differentiation. Genom Data. 2015 Sep;5:82-8. PubMed PMID: 26484231; PubMed Central PMCID: PMC4583626.
  • Liu Y, Lu X, Huang L, Wang W, Jiang G, Dean KC, Clem B, Telang S, Jenson AB, Cuatrecasas M, Chesney J, Darling DS, Postigo A, Dean DC. Erratum: Different thresholds of ZEB1 are required for Ras-mediated tumour initiation and metastasis. Nat Commun. 2015 Mar 19;6:6699. PubMed PMID: 25789446.
  • Metzler MA, Venkatesh SG, Lakshmanan J, Carenbauer AL, Perez SM, Andres SA, Appana S, Brock GN, Wittliff JL, Darling DS. A systems biology approach identifies a regulatory network in parotid acinar cell terminal differentiation. PLoS One. 2015;10(4):e0125153. PubMed PMID: 25928148; PubMed Central PMCID: PMC4416001.
  • Liu Y, Lu X, Huang L, Wang W, Jiang G, Dean KC, Clem B, Telang S, Jenson AB, Cuatrecasas M, Chesney J, Darling DS, Postigo A, Dean DC. Different thresholds of ZEB1 are required for Ras-mediated tumour initiation and metastasis. Nat Commun. 2014 Dec 1;5:5660. PubMed PMID: 25434817.
  • Kim J, Li J, Venkatesh SG, Darling DS, Rempala GA. Model discrimination in dynamic molecular systems: application to parotid de-differentiation network. J Comput Biol. 2013 Jul;20(7):524-39. PubMed PMID: 23829652; PubMed Central PMCID: PMC3704053.
  • Siles L, Sánchez-Tilló E, Lim JW, Darling DS, Kroll KL, et al. ZEB1 imposes a temporary stage-dependent inhibition of muscle gene expression and differentiation via CtBP-mediated transcriptional repression. Mol Cell Biol. 2013 Apr;33(7):1368-82. PubMed PMID: 23339872; PubMed Central PMCID: PMC3624276.
  • Sánchez-Tilló E, de Barrios O, Siles L, Amendola PG, Darling DS, et al. ZEB1 Promotes invasiveness of colorectal carcinoma cells through the opposing regulation of uPA and PAI-1. Clin Cancer Res. 2013 Mar 1;19(5):1071-82. PubMed PMID: 23340304.
  • Jaejik Kim, Jiaxu Li, Srirangapatnam G. Venkatesh, Douglas S. Darling and Grzegorz A. Rempala. (2013) Model Discrimination in Dynamic Molecular Systems: Application to Parotid De-differentiation Network. Journal of Computational Biology, 20(7):524-39. PMID: 23829652.
  • Laura Siles, Ester Sánchez-Tilló, Jong-Won Lim, Douglas S. Darling, Kristen L. Kroll, Antonio Postigo. (2013) ZEB1 imposes a temporary stage-dependent inhibition of muscle gene expression and differentiation via CtBP-mediated transcriptional repression.  Molecular Cell Biology, 33: 1368 - 1382. PMID: 23339872, PMCID: PMC3624276.