Project 2

Regulation of Lactosaminyl Glycan Biosynthesis in Hematopoietic Cells

Abstract

Any insufficiency of hematopoiesis, such from iatrogenic causes secondary to cancer chemoradiotherapy, from exposure to toxins (e.g., benzene), or from unknown etiology, poses significant risks of mortality, mostly due to bleeding and infections.  All of these conditions may be ameliorated by more rapid and effective re-establishment of hematopoietic function.  There is increasing evidence that sialyl and fucosyl derivatives of lactosaminyl glycans, such as sialyl Lewis X structures, mediate adhesive interactions critical to hematopoietic stem and progenitor cell homeostasis.  However, the glycan structural profiles of early hematopoietic cells, the glycosylation network governing their stage- and lineage-specific expression, and their precise participation in hematopoietic process(es), are largely unknown.  In this proposal, we will focus on the biosynthetic pathways governing sialofucosylations that modify lactosamine structures.  We will extend these studies to examine how glycosyltransferases influence commitment into myeloid and megakaryocyte lineages.  By implementing a three-tiered approach of glycogene expression query, enzymatic activity profiling, and glycan structural analysis, we will elucidate hematopoietic stem and progenitor cell surface glycan structures and identify the key glycan-modifying enzymatic activities occupying the biosynthetic checkpoints in the production of these structures.  In addition to characterizing the conventional ER/Golgi-based network of glycosyltransferases, we will explore a novel pathway of glycan synthesis uncovered by recent studies in our lab. The canonical view of glycan synthesis holds that glycosylation events occur only within the same cell that expresses the cognate glycosyltransferase(s).  However, we have evidence for a novel alternate pathway of glycosylation whereby hematopoietic cell surface glycans can be remodeled extracellularly, by “extrinsic” enzymes originating from distal sources, and point to the idea of extrinsic enzymes as factors in regulating hematopoiesis.  The extent of the involvement of the extrinsic enzymes in generating hematopoietic cell surface glycans will be evaluated by forced expression of circulatory recombinant enzymes, and also by construction of bone marrow chimeras using donor hematopoietic cells with specific glycosyltransferase defects into wild-type recipients, and vice versa.  The biologic roles of specific glycans, whether they are of intrinsic or extrinsic construction, will be assessed by ex vivo adhesion and clonogenic assays and by in vivo homing, retention, repopulation, and trafficking parameters.  A mathematical modeling framework will be developed to enhance our understanding of dynamic glycosylation pathways, and therefore how they can be manipulated for therapeutic benefit.  We anticipate the results of our studies will yield novel strategies for glycan engineering of hematopoietic cell surfaces towards modification of their biologic behavior.

Dr. Joseph Lau has been involved in research in the glycosciences for over 30 years.  He is best recognized for his pioneering work in understanding the glycosyltransferases, enzymes that constructs the glycan “coats” of each cell that form the critical interphase of how cells communicate with their surrounding environment.   Dr. Lau was born in Hong Kong, but immigrated to Honolulu, Hawaii with his family where he spend his childhood years bodysurfing and scuba diving until graduation from high school.  He received his undergraduate degree from University of Washington, and his Ph.D. in Biochemistry from Purdue University.  After his postdoctoral training at the Johns Hopkins School of Medicine under the tutelage of Drs. William Lennarz and Don Cleveland, Dr. Lau joined the faculty at Roswell Park Cancer Institute, where he holds the title of Distinguished Professor of Oncology.  Dr. Lau also holds a joint appointment at the State University of New York at Buffalo.When he’s not doing research, he is an avid skier and martial arts practitioner.  When home, one can find him on early weekend mornings running the wooded trails with his dog.

Melinda (Mindy) Haarmeyer, M.S. (left) and Val Anderssen (right) are research technicians and the foundations to the Lau Laboratory.  Mindy is a 2011 biochemistry graduate (M.A.) from SUNY at Buffalo.  Val is a graduate from the SUNY at Roswell Park with a Masters in Natural Sciences.  For the PEG, Mindy assists in immunocytochemistry, stem cell isolation, flow analysis, and is the gatekeeper to the animal colonies.  Val assists in various aspects of protein chemistry, enzymatic assays, molecular biology, and tissue culture.  For relaxation, Mindy plays the violin.  In past ensembles, she has been the leader principal of the second violins in chambers strings.  Val loves the outdoors, hiking in the summer and cross-country skis in the winter.  Val is often seen braving the Buffalo winters commuting on her bike.

Christopher Dougher

Christopher W. Dougher is a Predoctoral Candidate and native of Buffalo, NY.  He received his Bachelor’s degree in Premedical Studies from the University of Notre Dame in 2007.  His research utilizes a circulatory ST6Gal-1 over expression-model to study changes to marrow subsets under conditions of hematopoietic demand.  In particular, Chris is interested in the functional interplay between intrinsically and extrinsically produced enzyme among these cell populations.  In his free time, Chris enjoys hiking, traveling, and restoring vintage sports cars with his father.

Charles Manhardt

Charles Manhardt is a PhD student on Dr. Lau’s team. He obtained his MS at the University at Albany studying developmental biology.  His project in the Lau lab focuses on the role platelets play in the novel mechanism of extrinsic glycosylation.  He was part of the group from the Lau lab which documented that platelets can support extracellular sialylation by supplying the sugar donor substrate. He is now working out some of the details of this mechanism and how it works in vivo. In his free time, Chuck likes to spend time hiking, running, and snowboarding.  He is also a big Buffalo sports fan and thinks this is the year.

Nemeth, Michael

Dr. Michael Nemeth is an Assistant Professor in the Departments of Medicine and Immunology at Roswell Park Cancer Institute. His research program focuses on the mechanisms that regulate the development and maintenance of hematopoietic stem cells and how similar mechanisms operate in leukemia stem cells. Dr. Nemeth earned his undergraduate degree from Duke University and his PhD from Dartmouth College.  Dr. Nemeth joined the faculty at Roswell Park following a post-doctoral fellowship at the National Human Genome Research Institute. Dr. Nemeth is an avid runner and maintains a connection to his Massachusetts roots as a discreet fan of all Boston sports teams.

Sriram Neelamegham

Prof. Sriram Neelamegham is a Professor of Chemical Engineering at the State University of New York at Buffalo. His laboratory works in the areas of Inflammation/Leukocyte Biology, Thrombosis and Hemostasis, and Systems Biology. In particular, he is interested in applying quantitative experimental and computational models to study human diseases with an eye towards clinical translation. The Neelamegham laboratory develops small molecule inhibitors of glycosylation. They use these reagents along with genome editing methods to identify glycosylation related pathways that control human leukocyte binding to vascular endothelial cells during inflammation. The group also develops cell adhesion engineering methods to target stem cells to the infarcted heart in large animal models. Finally, they produce ‘glycoProbes’ for mass spectrometry based glycoproteomics experiments, in order to interrogate cells and learn how nature controls glycan microheterogeneity. Dr. Neelamegham obtained his Ph.D. in Bioengineering from the Rice University and performed post-doctoral research in Leukocyte Biology at the Baylor College of Medicine. In his spare time, Sriram enjoys long bike rides with his boys.

 

Contact Information:
Joseph Lau, Ph.D.
Department of Molecular and Cellular Biology
Tumor Immunology and Immunotherapeutics Program
Roswell Park Cancer Institute
Elm and Carlton Streets
Buffalo, New York 14263
Office Number: 716-845-8914
Email: joseph.lau@roswellpark.org

Sriram Neelamegham, Ph.D.
Bioengineering Laboratory
Department of Chemical Engineering
906 Furnas Hall
State University of New York at Buffalo
Buffalo, NY 14260-4200
Phone: (716) 645-1200
Fax : (716) 645-3822
E-mail: neel@buffalo.edu