Kelly McNagny, Ph.D.
Professor, Department of Medical Genetics
Co-Director, Biomedical Research Centre
Member of the Stem Cell Network Centre of Excellence (Sub-Chair, Training and Education Committee)
Member of the AllerGen Network Centre for Excellence (Co-Director, Biomarkers and Bioinformatics Program)
UBC Centre for Blood Research (Member of the Steering Committee)
My laboratory is interested in two aspects of hematopoietic stem cell biology: 1) the networks that regulates the commitment of multipotent progenitors to a specific lineage, and 2) the surface receptors expressed by hematopoietic precursor cells that regulate their interacts with their microenvironment and by mature cells that regulate their trafficking in disease.
We are focusing on the regulatory mechanisms that govern mast cell and eosinophil production. These are relatively rare cells that are responsible for most of the pathology in chronic allergy and asthma and therefore may represent good targets for clinical intervention. We are using a number of transgenic mouse models to identify the factors that govern mast cell and eosinophil formation, homing and function and to perturb these processes during normal development.
Surface molecules expressed by hematopoietic cells
We have focused predominantly on CD34-type proteins. CD34 is a cell surface sialomucin and the most widely used marker of hematopoietic stem cells and vascular endothelia. Recently we identified two novel receptors, Podocalyxin (also called Podxl, GCTM2, MEP21, gp135, Thrombomucin and PCLP1) and Endoglycan (Podxl2) that are also expressed by hematopoietic stem/progenitor cells and vasculature. We have shown that, together with CD34, these additional molecules comprise a gene family and that all three are probably derived from a common ancestral gene. Surprisingly, despite the extensive use of CD34 as a stem cell marker, virtually nothing is known of its function and it has alternatively be touted as a(n):
1) blocker of HSC differentiation
2) enhancer of HSC proliferation
3) bone marrow homing receptor
4) pro-adhesive receptor
5) anti-adhesive receptor
Targeted deletion of the CD34 gene in mice has only fueled the debate concerning its function since these mice exhibit extremely subtle perturbations in normal hematopoietic function that could be used to support each of the above hypotheses.
The discovery of two novel members of this gene family with overlapping expression patterns, has allowed us to: (1) re-evaluate these results in light of the potential for functional compensation and, (2) to generate compound mutant mice to test the true function of these receptors. In aggregate, these studies have allowed us to prove that the CD34 family of proteins function predominantly as anti-adhesion molecules, or “molecular Teflon”. Thus, they enhance the mobility and invasiveness of hematopoietic cells and on non-hematopoietic cells they are able to disrupt cell-cell junctional complexes between neighboring adherent cells (vascular endothelia or podocytes in the kidney, for example). This is not a constitutive function, but is tightly regulated by a set of proteins that bind to the cytoplasmic tail of CD34-type proteins and regulate their subcellular localization and proximity to adhesion molecules. Preliminary data suggest that loss of CD34-type proteins leads to defects in hematopoietic function by preventing the HSC from entering the appropriate microenvironments (due to excessive adhesion). Similarly, CD34, itself, aids in the trafficking of mucosal inflammatory cells (mainly eosinophils and mast cells) and mice lacking CD34 are remarkably resistant to a variety of inflammatory diseases. On endothelial cells we find that these proteins can regulate polarity, cell-cell adhesion and vascular permeability. Finally, we have shown that these same “anti-adhesion” molecules are upregulated in an aggressive subset of epithelial tumors and lead to increased invasiveness and loss of cell polarity. They may, thus, prove to be excellent prognostic indicators of poor outcome tumors and provide a means of identifying these cancers early for aggressive therapy.
Innate Immune Response and Inflammatory Disease
Through our studies of CD34 family and innate inflammatory cells we have developed expertise in a large array of mouse models of human disease. These include lung inflammatory disease (Th2 driven allergic asthma, Th1/Th1 driven hypersensitivity pneumonitis, and pulmonary fibrosis),gut inflammatory diseases ( Crohn’s disease and ulcerative colitis) and a variety of others. Currently we are investigating the role of both, the newly discovered innate lymphoid cells (ILCs), and the neonatal microbiome in these mouse models of human disease. These are providing fascinating insights into the origins of, and susceptibility to, chronic inflammatory disease. Our focus is now on how manipulation of these cells and the microbiome could be exploited for the treatment of human disease.
Kidney Function and Cell Based Therapy
Through our studies of stem cell, podocalyxin and it role in kidney morphogenesis we have developed a long-term interest in the causes of chronic kidney disease and therapeutic approaches to treating this extremely important malady. Through a key collaboration with Dr. Beno Freedman at the U. of Washington we are exploring the utility of kidney organoids derived from human induced pluripotent stem cell (iPSC) as tools for identifying novel strategies for treating renal failure.
Selected Publications (See all publications)
Lo B, Gold MJ Hughes MR, Antignano F, Zaph C, Harder KW, McNagny, KM. Retinoic-acid-receptor-related orphan nuclear receptor alpha and group 3 innate lymphoid cells drive fibrosis in a mouse model of Crohn’s disease. Science Immunology 1, eaaf8864, 2016.
Freedman BS, Brooks CR, Lam AQ, Fu H, Morizane R, Agrawal V, Saad AF, Li MK, Hughes MR, Vander Werff R, Peters DT, Luo J, Musunuru K, McNagny KM, Steinman TI, Zhou J, Lerou PH, Bonventre JV. Three-Dimensional Differentiation of Epiblast Spheroids to Kidney Organoids Models Stage-Specific Epithelial Physiology, Morphogenesis, and Disease. Nature Comm 6: 8715, 2016.
Snyder KA, Hughes MR, Hedberg B, Brandon J, Hernaez DC, Bergqvist P, Cruz E, Po K, Graves ML, Turvey ME, Nielsen JS, Wilkins JA, McColl SR, Babcook JS, Roskelley CD, McNagny KM. Podocalyxin enhances breast tumor growth and metastasis and is a therapeutic target for monoclonal antibody therapy. Breast Cancer Research. 17:46, 2015.
DeBruin EJ, Hughes MR, Jian Z, Liu A, Lopez M, Lo B, Sina C, Abraham T, KM McNagny. Podocalyxin regulates lung vascular permeability by altering endothelial cell adhesion. PLoS ONE 9; e108881, 2014.
Russell SL, Gold MJ, Willing BP, Reynolds L, Thorson L, Blanchet MR, Finlay BB*, McNagny KM*. Perinatal antibiotic-induced shifts in gut microbiota have differential effects on inflammatory lung disease. J. Allergy and Clin Immunol. 135: 100-109, 2015. *Co-corresponding authors.
Gold MJ, Antignano F, Halim TYF, Blanchet M-R, Zaph C, Takei F, McNagny KM. Group 2 Innate Lymphoid Cells facilitate sensitization to local, but not systemic, Th2-allergen exposures. J. Allergy and Clin Immunol. 133: 1142-8, 2014.
Russell SL, Gold MJ, Hartmann M, Willing BP, Thorson T, Wlodarska M, Gill N, Blanchet M-R, Mohn WW, McNagny KM* and BB Finlay*. Early life antibiotics increase susceptibility to allergic asthma. EMBO Reports, 13(5): 440-7, 2012. *Co-corresponding authors.
Strilic B, Kucera T, Eglinger J, Hughes MR, McNagny KM, Tsukita S, Dejana E, Ferrara N and Lammert E. The molecular basis of vascular lumen formation in the developing mouse aorta. Developmental Cell 17:505-15, 2009. (Faculty of 1000 – top choice).
Nielsen JS and McNagny KM. functions of the CD34 family. J Cell Science 121: 2683-2692, 2008
Blanchet MR, Maltby S, Haddon DJ, Merkens H, Zbytnuik L and McNagny KM. CD34 Facilitates The Development of Allergic Asthma. Blood 110:2005-2012, 2007
Doyonnas R*, Nielsen J*, Drew E, Chelliah SJ, Hara T. Miyajima A, and McNagny, KM. Podocalyxin is a CD34-related marker of murine hematopoietic stem cells and embryonic erythroid cells. Blood. Plenary paper 105:4170-4178, 2005
Drew E, Merzaban J, Seo W, Ziltener HJ, and McNagny, KM. CD34 and CD43 inhibit mast cell adhesion and are required for optimal mast cell reconstitution. Immunity. 22: 43-57, 2005
Somasiri A, Nielsen J, Makretsov N, Gilks CB, Huntsman D, Gelmon KA, Kershaw DB, and McNagny KM*, Roskelley C.* Overexpression of the anti-adhesin Podocalyxin is an independent predictor of breast cancer progression. Cancer Research 64: 5068-5073, 2004
McNagny K and Graf T. Making eosinophils through subtle shifts in transcription factor expression. J Exp Med. 195: F43-7, 2002.
Doyonnas R, Kershaw DB, Duhme C, Merkens H, Chelliah S, Graf T and McNagny KM. Anuria, omphalocele and perinatal lethality in mice lacking the CD34-related protein, Podocalyxin. J. Exp. Med 194: 13-27, 2001
Michael Hughes, PhD Research Associate
Jessica Cait, Graduate Research Assistant
Diana Canals Hernaez, Graduate Research Assistant
Bernard Lo, Graduate Academic Assistant
Ido Refaeli, Graduate Research Assistant