Craig T. Lefort, PhD

Assistant Professor of Surgery (Research)
Division of Surgical Research at Rhode Island Hospital and Warren Alpert Medical School of Brown University

Rhode Island Hospital
Middle House 203
593 Eddy Street
Providence, RI 02903

Phone: 401.444.2353
Email: craig_lefort@brown.edu

Craig T. Lefort, PhD

Bio

Craig T. Lefort, PhD, is an Assistant Professor of Surgery (Research) in the Division of Surgical Research at Rhode Island Hospital and Warren Alpert Medical School of Brown University. He is the Principal Investigator of a 1-year pilot project from the CPVB COBRE: “Integrin activation regulates neutrophil trafficking during respiratory infection.” Dr. Lefort’s project investigates the potential for modulating integrin activity to control the innate immune response to respiratory infection so as to reduce acute lung injury while maintaining host immune defense.

Dr. Lefort completed his undergraduate (Columbia University) and doctoral studies (University of Rochester) in Biomedical Engineering, followed by postdoctoral training in Immunology at the University of Rochester and at La Jolla Institute for Allergy and Immunology in southern California. He was awarded a Scientist Development Grant from the American Heart Association in 2012. Since joining Rhode Island Hospital, Dr. Lefort has also received a Medical Research Grant from the Rhode Island Foundation.

Dr. Lefort’s research interests are focused on understanding the mechanisms of neutrophil trafficking throughout the body during the inflammatory response to infection or injury. Neutrophils are one of the first innate immune cell types that undergo recruitment into inflamed tissues and are essential for fighting infection, but they also contribute to inflammatory diseases. As a postdoctoral fellow under the mentorship of Dr. Klaus Ley, Dr. Lefort studied how integrin receptors on the neutrophil surface are activated to mediate cell adhesion to the blood vessel wall. His long-term goals include developing strategies to therapeutically target neutrophils in a more specific manner while preserving other critical functions of the immune system.

COBRE Abstract

Integrin activation regulates neutrophil trafficking within the murine lung

Acute respiratory infections account for more than four million deaths annually worldwide. In hospital settings, the bacterial pathogen P. aeruginosa is one of the most common sources of respiratory infection. Neutrophils are the first innate immune cells to respond to infection, and are essential to mount the inflammatory response and eliminate the infectious source. To perform this important task, neutrophils must exit the circulation and migrate into the airways of the lung where the microbes reside. However, excessive recruitment of neutrophils into the interstitial space and airways can result in tissue damage, lung injury and respiratory failure. Our studies will investigate the role of integrin activation in this process. Integrins are receptors that play key roles in neutrophil homing throughout the body by mediating adhesion to the endothelial cell lining of blood vessels (β2 integrins) and providing traction to migrate through tissue (β2 and β1 integrins). To play these diverse roles, integrins can exist in multiple activation states with a range of ligand binding affinities. Talin-1 and Kindlin-3 regulate β2 integrin affinity by binding to their short cytoplasmic tail and inducing structural changes that are propagated to the ligand binding integrin headpiece. We have recently discovered that Talin-1 and Kindlin-3 have distinct roles in activating the β2 integrin LFA-1 on neutrophils. Although the role of integrin activating proteins has been extensively studied in the context of neutrophil adhesion in post-capillary venules with rapid shear flow, it has not been investigated in the context of the pulmonary vasculature. In the lung, neutrophils primarily emigrate from the capillary network that envelops the alveolar air sacs where gas exchange occurs. Alveolar capillaries have a narrow diameter and neutrophils become lodged within these vessels when they stiffen during an inflammatory response. This setting will allow us to determine how integrin activation is involved in neutrophil migration across the endothelial barrier, through the interstitium and across the epithelial cell lining of the alveolus. Based on preliminary studies, we hypothesize that neutrophils lacking Talin-1 and Kindlin-3 will migrate into airways infected with P. aeruginosa less efficiently than wild-type neutrophils. In Aim 1, we will measure the fraction of wild-type and Talin-1 or Kindlin-3-deficient neutrophils that are in the vasculature, interstitium and airways of mice during P. aeruginosa infection. In Aim 2, we will evaluate the effects of two drugs that modulate β2 integrin activation, XVA143 and Leukadherin-1, on neutrophil migration into the airways, eradication of P. aeruginosa, and tissue inflammation. Upon completion of this work we will have a greater understanding of the mechanisms of neutrophil trafficking during acute respiratory bacterial infection. These studies may suggest that regulators of integrin activation should be tested in future experiments for their therapeutic efficacy in dampening inflammation while preserving adequate host defense of the lung.

Publications

Kaba NK, Schultz J, Law FY, Lefort CT, Martel-Gallegos G, Kim M, Waugh RE, Arreola J, Knauf PA. (2008). Inhibition of Na+/H+ exchanger enhances low pH-induced L-selectin shedding and beta2-integrin surface expression in human neutrophils. Am. J. Physiol. Cell Physiol. 295:C1454-1463. PMCID: PMC2584992

Lefort CT, Hyun YM, Schultz JB, Law FY, Waugh RE, Knauf PA, Kim M. (2009). Outside-in signal transmission by conformational changes in integrin Mac-1. J. Immunol. 183:6460-6468. PMCID: PMC2860599

Hu X, Kang S, Lefort CT, Kim M, Jin MM. (2010). Combinatorial libraries against libraries for selecting neoeptiope activation-specific antibodies. Proc. Nat. Acad. Sci. 107:6252-6257. PMCID: PMC2851959

Lefort CT, Wojciechowski K, Hocking DC. (2011). N-cadherin cell-cell adhesion complexes are regulated by fibronectin matrix assembly. J. Biol. Chem. 286:3149-3160. PMCID: PMC3024807

Tang J, Zarbock A, Gomez I, Wilson CL, Lefort CT, Stadtmann A, Bell B, Huang LC, Ley K, Raines EW. (2011). Adam17-dependent shedding limits early neutrophil influx but does not alter early monocyte recruitment to inflammatory sites. Blood. 118:786-794. PMCID: PMC3142912

Lefort CT, Hyun YM, Kim M. (2012). Monitoring Integrin Activation by Fluorescence Resonance Energy Transfer. Methods Mol. Biol. 757:205-14. PMID: 21909915

Rillahan CD, Antonopoulos A, Lefort CT, Sonon R, Azadi P, Ley K, Dell A, Haslam SM, Paulson JC. (2012) Global metabolic inhibitors of sialyl- and fucosyltransferases. Nat. Chem. Biol. 8:661-668. PMCID: PMC3427410

Lefort CT, Rossaint J, Moser M, Petrich BG, Zarbock A, Monkley SJ, Critchley DR, Ginsberg MH, Fässler R, Ley K. (2012) Distinct roles for talin-1 and kindlin-3 in LFA-1 extension and affinity regulation. Blood. 119:4275-4282. PMCID: PMC3359742

Lefort CT, Ley K. (2012) Neutrophil arrest by LFA-1 activation. Front. Immunol. 3:157. PMCID: PMC3373145

Stadtmann A, Germena G, Block H, Boras M, Rossaint J, Sundd P, Lefort CT, Fisher CI, Buscher K, Gelschefarth B, Urzainqui A, Gerke V, Ley K, Zarbock Z. (2013) The PSGL-1/L-selectin signaling complex regulates neutrophil adhesion under flow. J. Exp. Med. 210:2171-2180. PMID:24127491.

Ye F, Petrich BG, Anekal P, Lefort CT, Shattil SJ, Moser M, Fässler R, Ginsberg MH. (2013) The mechanism of Kindlin-mediated activation of integrin αIIbβ3. Curr. Biol. 23:2288-2295. PMID:25210614.

Project Updates
Mentors

Jonathan S. Reichner, PhD
Professor of Surgery (Research)
Rhode Island Hospital

Elizabeth O. Harrington, PhD
Associate Dean, Office of Graduate and Postdoctoral Studies
Professor of Medicine (Research)
Brown University
Providence VA Medical Center