Macrophages are specialized cells of our immune system. They provide our first line of defence against invading micro-organisms starting the immune response and are called “killer” macrophages. When our body has finished killing off unwanted invaders, these macrophages change their function and help in cleaning up the injured area. These are called “healer” macrophages. During clean up, macrophages tidy up debris, promote wound healing and scar formation and shut off the immune response. In some inflammatory diseases, like inflammatory bowel disease, the immune response gets out of control. Macrophages are the largest producers of tumour necrosis factor alpha in the gut and an antibody directed against this macrophage product is an effective therapy for patients with Crohn’s disease and ulcerative colitis. The goal of my research is to understand how these macrophages make the switch from “killers” to “healers” with the hope of pushing macrophages to “healers” during inflammatory bowel disease


Activity of SHIP, Which Prevents Expression of Interleukin 1ß, Is Reduced in Patients With Crohn's Disease.
Ngoh EN, Weisser SB, Lo Y, Kozicky LK, Jen R, Brugger HK, Menzies SC, McLarren KW, Nackiewicz D, van Rooijen N, Jacobson K, Ehses JA, Turvey SE, Sly LM
DOI: 10.1053/j.gastro.2015.09.049
PubMed: 26481854

a-Integrin expression and function modulates presentation of cell surface calreticulin.
Liu CC, Leclair P, Monajemi M, Sly LM, Reid GS, Lim CJ
DOI: 10.1038/cddis.2016.176
PubMed: 27310876

Intravenous immunoglobulin skews macrophages to an anti-inflammatory, IL-10-producing activation state.
Kozicky LK, Zhao ZY, Menzies SC, Fidanza M, Reid GS, Wilhelmsen K, Hellman J, Hotte N, Madsen KL, Sly LM
DOI: 10.1189/jlb.3vma0315-078r
PubMed: 26216934

The Crohn's disease-associated polymorphism in ATG16L1 (rs2241880) reduces SHIP gene expression and activity in human subjects.
Ngoh EN, Brugger HK, Monajemi M, Menzies SC, Hirschfeld AF, Del Bel KL, Jacobson K, Lavoie PM, Turvey SE, Sly LM
DOI: 10.1038/gene.2015.30
PubMed: 26226011

Phosphatase regulation of macrophage activation.
Kozicky LK, Sly LM
DOI: 10.1016/j.smim.2015.07.001
PubMed: 26216598

Impaired NLRP3 inflammasome activity during fetal development regulates IL-1ß production in human monocytes.
Sharma AA, Jen R, Kan B, Sharma A, Marchant E, Tang A, Gadawski I, Senger C, Skoll A, Turvey SE, Sly LM, Côté HC, Lavoie PM
DOI: 10.1002/eji.201444707
PubMed: 25311115

Arginase activity in alternatively activated macrophages protects PI3Kp110d deficient mice from dextran sodium sulfate induced intestinal inflammation.
Weisser SB, Kozicky LK, Brugger HK, Ngoh EN, Cheung B, Jen R, Menzies SC, Samarakoon A, Murray PJ, Lim CJ, Johnson P, Boucher JL, van Rooijen N, Sly LM
DOI: 10.1002/eji.201343981
PubMed: 25124254

Combined immunodeficiency associated with homozygous MALT1 mutations.
McKinnon ML, Rozmus J, Fung SY, Hirschfeld AF, Del Bel KL, Thomas L, Marr N, Martin SD, Marwaha AK, Priatel JJ, Tan R, Senger C, Tsang A, Prendiville J, Junker AK, Seear M, Schultz KR, Sly LM, Holt RA, Patel MS
DOI: 10.1016/j.jaci.2013.10.045
PubMed: 24332264

Mutant IDH1 promotes leukemogenesis in vivo and can be specifically targeted in human AML.
Chaturvedi A, Araujo Cruz MM, Jyotsana N, Sharma A, Yun H, Görlich K, Wichmann M, Schwarzer A, Preller M, Thol F, Meyer J, Haemmerle R, Struys EA, Jansen EE, Modlich U, Li Z, Sly LM, Geffers R, Lindner R, Manstein DJ
DOI: 10.1182/blood-2013-03-491571
PubMed: 23954893

Generation and characterization of murine alternatively activated macrophages.
Weisser SB, McLarren KW, Kuroda E, Sly LM
DOI: 10.1007/978-1-62703-128-8_14
PubMed: 23179835

Depletion and reconstitution of macrophages in mice.
Weisser SB, van Rooijen N, Sly LM
DOI: 10.3791/4105
PubMed: 22871793

SHIP-deficient, alternatively activated macrophages protect mice during DSS-induced colitis.
Weisser SB, Brugger HK, Voglmaier NS, McLarren KW, van Rooijen N, Sly LM
DOI: 10.1189/jlb.0311124
PubMed: 21685246

A low carbohydrate, high protein diet slows tumor growth and prevents cancer initiation.
Ho VW, Leung K, Hsu A, Luk B, Lai J, Shen SY, Minchinton AI, Waterhouse D, Bally MB, Lin W, Nelson BH, Sly LM, Krystal G
DOI: 10.1158/0008-5472.can-10-3973
PubMed: 21673053

SHIP-deficient mice develop spontaneous intestinal inflammation and arginase-dependent fibrosis.
McLarren KW, Cole AE, Weisser SB, Voglmaier NS, Conlin VS, Jacobson K, Popescu O, Boucher JL, Sly LM
DOI: 10.1016/j.ajpath.2011.03.018
PubMed: 21640975

Alternative activation of macrophages by IL-4 requires SHIP degradation.
Weisser SB, McLarren KW, Voglmaier N, van Netten-Thomas CJ, Antov A, Flavell RA, Sly LM
DOI: 10.1002/eji.201041105
PubMed: 21469115

SHIP represses Th2 skewing by inhibiting IL-4 production from basophils.
Kuroda E, Antignano F, Ho VW, Hughes MR, Ruschmann J, Lam V, Kawakami T, Kerr WG, McNagny KM, Sly LM, Krystal G
DOI: 10.4049/jimmunol.1002778
PubMed: 21131429

Tyrosine phosphorylation of SHIP promotes its proteasomal degradation.
Ruschmann J, Ho V, Antignano F, Kuroda E, Lam V, Ibaraki M, Snyder K, Kim C, Flavell RA, Kawakami T, Sly L, Turhan AG, Krystal G
DOI: 10.1016/j.exphem.2010.03.010
PubMed: 20304029

The p110a and p110ß isoforms of class I phosphatidylinositol 3-kinase are involved in toll-like receptor 5 signaling in epithelial cells.
Ivison SM, Khan MA, Graham NR, Shobab LA, Yao Y, Kifayet A, Sly LM, Steiner TS
DOI: 10.1155/2010/652098
PubMed: 20953381

Modeling the functional heterogeneity of leukemia stem cells: role of STAT5 in leukemia stem cell self-renewal.
Heuser M, Sly LM, Argiropoulos B, Kuchenbauer F, Lai C, Weng A, Leung M, Lin G, Brookes C, Fung S, Valk PJ, Delwel R, Löwenberg B, Krystal G, Humphries RK
DOI: 10.1182/blood-2009-06-227603
PubMed: 19667399

SHIP represses the generation of IL-3-induced M2 macrophages by inhibiting IL-4 production from basophils.
Kuroda E, Ho V, Ruschmann J, Antignano F, Hamilton M, Rauh MJ, Antov A, Flavell RA, Sly LM, Krystal G
DOI: 10.4049/jimmunol.0900864
PubMed: 19710468

SHIP regulates the reciprocal development of T regulatory and Th17 cells.
Locke NR, Patterson SJ, Hamilton MJ, Sly LM, Krystal G, Levings MK
DOI: 10.4049/jimmunol.0803749
PubMed: 19542365

SHIP prevents lipopolysaccharide from triggering an antiviral response in mice.
Sly LM, Hamilton MJ, Kuroda E, Ho VW, Antignano FL, Omeis SL, van Netten-Thomas CJ, Wong D, Brugger HK, Williams O, Feldman ME, Houseman BT, Fiedler D, Shokat KM, Krystal G
DOI: 10.1182/blood-2008-06-166082
PubMed: 19139077

Derivation and characterization of murine alternatively activated (M2) macrophages.
Ho VW, Sly LM
DOI: 10.1007/978-1-59745-396-7_12
PubMed: 19347318

IgE-induced mast cell survival requires the prolonged generation of reactive oxygen species.
Sly LM, Kalesnikoff J, Lam V, Wong D, Song C, Omeis S, Chan K, Lee CW, Siraganian RP, Rivera J, Krystal G
DOI: 10.4049/jimmunol.181.6.3850
PubMed: 18768839

The inositol phosphatase SHIP controls Salmonella enterica serovar Typhimurium infection in vivo.
Bishop JL, Sly LM, Krystal G, Finlay BB
DOI: 10.1128/iai.01596-07
PubMed: 18426884

Linkage of Meis1 leukemogenic activity to multiple downstream effectors including Trib2 and Ccl3.
Argiropoulos B, Palmqvist L, Yung E, Kuchenbauer F, Heuser M, Sly LM, Wan A, Krystal G, Humphries RK
DOI: 10.1016/j.exphem.2008.02.011
PubMed: 18375036

Monocyte p110alpha phosphatidylinositol 3-kinase regulates phagocytosis, the phagocyte oxidase, and cytokine production.
Lee JS, Nauseef WM, Moeenrezakhanlou A, Sly LM, Noubir S, Leidal KG, Schlomann JM, Krystal G, Reiner NE
DOI: 10.1189/jlb.0906564
PubMed: 17369495

Re: the terminology issue for myeloid-derived suppressor cells.
Krystal G, Sly L, Antignano F, Ho V, Ruschmann J, Hamilton M
DOI: 10.1158/0008-5472.can-07-0211
PubMed: 17440115

The role of SHIP in macrophages.
Sly LM, Ho V, Antignano F, Ruschmann J, Hamilton M, Lam V, Rauh MJ, Krystal G
DOI: 10.2741/2276
PubMed: 17485263

The Flt3 receptor tyrosine kinase collaborates with NUP98-HOX fusions in acute myeloid leukemia.
Palmqvist L, Argiropoulos B, Pineault N, Abramovich C, Sly LM, Krystal G, Wan A, Humphries RK
DOI: 10.1182/blood-2005-12-007005
PubMed: 16861351

SHIP represses the generation of alternatively activated macrophages.
Rauh MJ, Ho V, Pereira C, Sham A, Sly LM, Lam V, Huxham L, Minchinton AI, Mui A, Krystal G
DOI: 10.1016/j.immuni.2005.09.003
PubMed: 16226502

The role of SHIP1 in macrophage programming and activation.
Rauh MJ, Sly LM, Kalesnikoff J, Hughes MR, Cao LP, Lam V, Krystal G
PubMed: 15494015

LPS-induced upregulation of SHIP is essential for endotoxin tolerance.
Sly LM, Rauh MJ, Kalesnikoff J, Song CH, Krystal G
DOI: 10.1016/j.immuni.2004.07.010
PubMed: 15308103

SHIP, SHIP2, and PTEN activities are regulated in vivo by modulation of their protein levels: SHIP is up-regulated in macrophages and mast cells by lipopolysaccharide.
Sly LM, Rauh MJ, Kalesnikoff J, Büchse T, Krystal G
DOI: 10.1016/j.exphem.2003.09.011
PubMed: 14662322

The 19-kDa Mycobacterium tuberculosis protein induces macrophage apoptosis through Toll-like receptor-2.
López M, Sly LM, Luu Y, Young D, Cooper H, Reiner NE
DOI: 10.4049/jimmunol.170.5.2409
PubMed: 12594264

Role of Src homology 2-containing-inositol 5'-phosphatase (SHIP) in mast cells and macrophages.
Rauh MJ, Kalesnikoff J, Hughes M, Sly L, Lam V, Krystal G
PubMed: 12546703

Survival of Mycobacterium tuberculosis in host macrophages involves resistance to apoptosis dependent upon induction of antiapoptotic Bcl-2 family member Mcl-1.
Sly LM, Hingley-Wilson SM, Reiner NE, McMaster WR
DOI: 10.4049/jimmunol.170.1.430
PubMed: 12496428

The role of SHIP in cytokine-induced signaling.
Kalesnikoff J, Sly LM, Hughes MR, Büchse T, Rauh MJ, Cao LP, Lam V, Mui A, Huber M, Krystal G
PubMed: 12692707

Salmonella enterica serovar Typhimurium periplasmic superoxide dismutases SodCI and SodCII are required for protection against the phagocyte oxidative burst.
Sly LM, Guiney DG, Reiner NE
DOI: 10.1128/iai.70.9.5312-5315.2002
PubMed: 12183590

1alpha,25-Dihydroxyvitamin D3-induced monocyte antimycobacterial activity is regulated by phosphatidylinositol 3-kinase and mediated by the NADPH-dependent phagocyte oxidase.
Sly LM, Lopez M, Nauseef WM, Reiner NE
DOI: 10.1074/jbc.m102876200
PubMed: 11461902

1alpha,25-dihydroxyvitamin D(3)-induced myeloid cell differentiation is regulated by a vitamin D receptor-phosphatidylinositol 3-kinase signaling complex.
Hmama Z, Nandan D, Sly L, Knutson KL, Herrera-Velit P, Reiner NE
DOI: 10.1084/jem.190.11.1583
PubMed: 10587349

Reconstitution of glucose uptake and chemotaxis in Pseudomonas aeruginosa glucose transport defective mutants.
Sly LM, Worobec EA, Perkins RE, Phibbs PV
PubMed: 8306210


Macrophage phenotype in inflammatory bowel disease
Macrophages are critical effector cells in the inflammatory response. Classically activated macrophages initiate the innate immune response and direct the activity of the acquired immune response. Upon resolution of inflammation, macrophages convert to an anti-inflammatory phenotype called alternatively activated. Alternatively activated macrophages promote debris scavenging, tissue remodelling and wound healing. Intriguingly, macrophages can be manipulated to move back and forth between these two phenotypes. During inflammatory disorders, like inflammatory bowel disease, switching macrophages to an alternatively activated phenotype, could dampen down inflammation and reduce disease. We are currently assessing the macrophage phenotype present during inflammatory bowel disease and mechanisms that we could use to switch macrophages to an anti-inflammatory phenotype during disease.

L-arginine metabolism in inflammation and fibrosis
L-arginine metabolism provides a key switch in macrophage phenotype. L-arginine can be metabolized by two pathways in macrophages. In classically activated macrophages during inflammation, the enzyme inducible nitric oxide synthase (iNOS) uses arginine to generate pro-inflammatory nitric oxide (NO). However, alternatively activated macrophages also express the enzyme arginase. Arginase metabolizes arginine leading to the production of polyamines, which promote cell growth, and proline, an essential component of collagen that can contribute to fibrosis. We are currently investigating the role of arginine metabolism by each of these pathways in inflammation and in fibrosis.

Role of the PI3K pathway in canonical alternative activation of macrophages
The src homology 2 domain-containing inositol 5'-phosphatase (SHIP) is a negative regulator of the phosphatidylinositol 3-kinase (PI3K) pathway. In vivo-differentiated SHIP deficient macrophages display a profoundly anergic phenotype and express phenotypic markers of alternative activation independent of canonical skewing by the Th2 cytokine, IL-4. SHIP protein levels are dramatically reduced when macrophages are skewed to an alternatively activate phenotype by IL-4 suggesting that increased PI3K activity may be required for canonical alternative activation of macrophages as well. We are currently characterizing the role of the PI3K pathway during canonical alternative activation of macrophages.

Honours & Awards

The G. Jeanette Thorbecke New Investigator Award from the Society for Leukocyte Biology (2012)

Canadian Association of Gastroenterology and Canadian Institutes of Health Research New Investigator Award (2009-2013)

Michael Smith Foundation for Health Research Scholar Award (2012-2021)

Research Group Members

Mahdis Monajemi, Doctoral Student
Jean Sauve
Lisa Kozicky
Susan Menzies, Lab Manager/Research Assistant Technician
Peter Dobranowski, Grad Student -Masters
Jordan Brundrett