Susan Bellis, Ph.D. - Assistant Professor

The broad focus of Dr. Bellis’ research is on the structure and function of integrin cell adhesion receptors. Current efforts are centered on two principal projects: (1) the role of differential glycosylation in regulating integrin function, and (2) engineering integrin-matrix interactions to enhance the performance of biomaterials used for bone tissue regeneration.

· The role of differential glycosylation in regulating integrin function.

For nearly two decades, the b1 integrin subunit has been reported to undergo differential glycosylation whenever cells are undergoing a major phenotype change, however few investigations have sought to elucidate the molecular mechanisms underlying this phenomenon. Our laboratory has determined that the b1 integrin is a substrate for the ST6Gal I sialyltransferase, and that changes in the level of a2-6 sialylation have a significant effect on integrin function. In particular, differential sialylation of integrins regulates cell adhesion and motility on extracellular matrix proteins such as collagen and fibronectin, and also serves as an “off switch” for galectin-binding. In vitro and in vivo studies from our group suggest that these collective effects of differential sialylation play a major role in regulating tumor cell metastasis, and monocyte recruitment to sites of inflammation.

· Engineering integrin-matrix interactions to enhance the performance of biomaterials used for bone tissue regeneration

In collaboration with several material scientists/bioengineers at UAB, we are developing 3-dimensional biomimetic scaffolds for use in bone tissue engineering. Our laboratory directs the cell biology/physiology component of this effort. Specifically, we analyze the behavior of mesenchymal stem cells grown on the biomaterials in order to gain insight into how these materials can be optimized to promote cell adhesion, survival, and stem cell differentiation along the osteoblast lineage. Moreover, when a material shows promise in in vitro cell culture studies, our laboratory performs in vivo biomaterials testing using a rat tibial implantation system.

		SUSAN L. BELLIS, Ph.D. Associate Professor
	Email: bellis@uab.edu Telephone: 205.934.3441 Fax: 205.975.9028 Bldg/Room: MCLM 982A

	Dr. Susan Bellis, Assistant Professor, received her B.A. at California State University at Long Beach and her B.S. at the University of California at Irvine. She obtained her Ph.D. in 1993 from the University of Rhode Island. After her Postdoctoral work at SUNY Health Sciences Center, Dr. Bellis joined the UAB faculty in 1998.
	Research The broad focus of Dr. Bellis’ research is on the structure and function of integrin cell adhesion receptors. Current efforts are centered on two principal projects: (1) the role of differential glycosylation in regulating integrin function, and (2) engineering integrin-matrix interactions to enhance the performance of biomaterials used for bone tissue regeneration. · The role of differential glycosylation in regulating integrin function. For nearly two decades, the b1 integrin subunit has been reported to undergo differential glycosylation whenever cells are undergoing a major phenotype change, however few investigations have sought to elucidate the molecular mechanisms underlying this phenomenon. Our laboratory has determined that the b1 integrin is a substrate for the ST6Gal I sialyltransferase, and that changes in the level of a2-6 sialylation have a significant effect on integrin function. In particular, differential sialylation of integrins regulates cell adhesion and motility on extracellular matrix proteins such as collagen and fibronectin, and also serves as an “off switch” for galectin-binding. In vitro and in vivo studies from our group suggest that these collective effects of differential sialylation play a major role in regulating tumor cell metastasis, and monocyte recruitment to sites of inflammation. · Engineering integrin-matrix interactions to enhance the performance of biomaterials used for bone tissue regeneration In collaboration with several material scientists/bioengineers at UAB, we are developing 3-dimensional biomimetic scaffolds for use in bone tissue engineering. Our laboratory directs the cell biology/physiology component of this effort. Specifically, we analyze the behavior of mesenchymal stem cells grown on the biomaterials in order to gain insight into how these materials can be optimized to promote cell adhesion, survival, and stem cell differentiation along the osteoblast lineage. Moreover, when a material shows promise in in vitro cell culture studies, our laboratory performs in vivo biomaterials testing using a rat tibial implantation system.
	Selected Publications ·Sawyer AA, Hennessy KM and Bellis SL. (2005) Regulation of mesenchymal stem cell attachment and spreading on hydroxyapatite by RGD peptides and adsorbed serum proteins. Biomaterials 26: 1467-1475. ·Sawyer, AA, Weeks, DM, Kelpke, S., McCracken, MC, and Bellis, SL. (2005) The effect of the addition of a polyglutamate motif to RGD on peptide tethering to hydroxyapatite and the promotion of mesenchymal stem cell adhesion. Biomaterials, 26: 7046-7056. ·Seales, EC, Jurado, GA, Brunson, BA, Wakefield, JK, Frost, AR, and Bellis, SL. (2005) Hypersialylation of b1 integrins, observed in colon adenocarcinoma, may contribute to cancer progression by upregulating cell motility. Cancer Res, 65: 4645-4652. ·Seales, EC, Shaikh, FM, Woodard-Grice, AV, Pooja Aggarwal, P, McBrayer,AC, Hennessy, KM, and Bellis SL. (2005) A PKC/ras/ERK signaling pathway activates myeloid fibronectin receptors by altering b1 integrin sialylation. J Biol Chem, 280: 37610-37615. ·Advincula, MC, Rahemtulla, FG, Advincula, RC, Ada, ET, Lemons, JE, and Bellis, SL. (2006) Osteoblast adhesion and matrix mineralization on sol-gel derived titanium alloy. Biomaterials, 27: 2201-2212. ·Sawyer, AA, Hennessy, KM and Bellis, SL (2007) The effect of adsorbed serum proteins, RGD and proteoglycan-binding peptides on the adhesion of mesenchymal stem cells to hydroxyapatite. Biomaterials, 28: 383-392.