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Laminin-332-Mediated Proliferation Control: Mechanisms Regulating Formation of the Epithelium

Buschmann, Mary McVey

Abstract Details

2010, PhD, University of Cincinnati, Medicine : Cell and Molecular Biology.
Normal epithelial cells rely on spatial cues from the extracellular matrix to proliferate, migrate, and survive. The extracellular matrix protein, laminin-332 (LM-332) seems to be particularly important in proliferation control during re-formation of a wounded epithelium. Inhibition of the LM-332-cell interaction prevents wound healing in keratinocytes and mammary epithelial cells. Treatment of normal renal epithelial cells with LM-332 rich medium increases the rate of proliferation, and inhibition of the LM-332-cellular interaction prevents proliferation in mammary epithelial and rat bladder carcinoma cells. Despite this information, the mechanism of LM-332-mediated proliferation control is largely unknown. The goal of the studies described here was to understand the requirement for LM-332 in proliferation control to form a polarized epithelium using the Madin Darby Canine Kidney (MDCK) cell model system. LM-332 expression was turned on at low cell density when cells were proliferative, and turned off and degraded upon re-formation of a quiescent epithelium. Furthermore, the suppression of LM-332 by expression of an shRNA targeted against the LMα3 subunit induced a G1 cell cycle arrest, likely through a mechanism mediated by p21waf1 inhibition of the cyclin E/cdk2 complex. The LMα3 shRNA-mediated proliferation arrest, however could not be validated, as the G1 block could not be rescued by plating cells on, or exposing cells to, endogenous LM-332, or by co-expression of human LMα3. Also, inhibition of the LM-332 receptors, integrins α3β1 and α6β4, did not cause proliferative arrest to a similar extent as cell expressing the shRNA, and last, expression of three additional siRNAs specific for the LMα3 chain did not alter proliferation. Instead, studies using the new siRNAs indicated that LM-332 is important for cell spreading and morphogenesis of the epithelium. All of the studies presented in this work collectively suggest that deposition of LM-332 plays an important role in the regulation of cell spreading, morphogenesis, and possibly proliferation, to establish a polarized epithelium.
Susanne Wells, PhD (Committee Chair)
Karl Matlin, PhD (Committee Member)
Susan Waltz, PhD (Committee Member)
Anil Menon, PhD (Committee Member)
Jonathan Jones, PhD (Committee Member)
260 p.

Recommended Citations

Citations

  • Buschmann, M. M. (2010). Laminin-332-Mediated Proliferation Control: Mechanisms Regulating Formation of the Epithelium [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1275661166

    APA Style (7th edition)

  • Buschmann, Mary. Laminin-332-Mediated Proliferation Control: Mechanisms Regulating Formation of the Epithelium. 2010. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1275661166.

    MLA Style (8th edition)

  • Buschmann, Mary. "Laminin-332-Mediated Proliferation Control: Mechanisms Regulating Formation of the Epithelium." Doctoral dissertation, University of Cincinnati, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1275661166

    Chicago Manual of Style (17th edition)