The pulmonary vasculature is a target for inflammation and thrombosis in conditions including acute lung injury (ALI), ischemia/reperfusions (I/R) and sepsis. The endothelial cell (EC) transmembrane glycoprotein, thrombomodulin (TM), controls these processes directly and via binding and """"""""redirecting"""""""" the activities of thrombin, from fibrin formation and its pro-inflammatory ability to activate vascular cells, to activate protein C (APC) that inhibits coagulation and inflammation. Loss of TM in EC aggravates lung diseases. Infusions of recombinant APC and TM are helpful in treatment of some forms of ALI, but these drugs are rapidly eliminated, do not anchor onto the EC lumen, lack interaction with EC partners such as Endothelial Protein C Receptor (EPCR), and predispose to bleeding. We posit that anchoring TM on EC will provide more specific, comprehensive, efficient and safe effects and may be used to design advanced targeted therapeutic interventions. We fused a single-chain variable fragment (scFv) of Cell Adhesion Molecule PECAM-1 antibody with active recombinant TM or its domains (scFv/TM). In pilot studies, scFv/TM, but not TM, bound to the pulmonary EC and protected from thrombosis, inflammation and edema in mouse models of lung I/R and LPS/hyperoxia, without bleeding. In this grant application we will define mechanism(s) of effects of scFv/TM and its proposed mutated iterations that specifically target selected vascular areas and pathological pathways, in order to initiate translation of this promising novel therapeutic strategy into the clinical domain. We will pursue the following specific aims:
Aim 1 : Assess """"""""benefit/risk"""""""" ratio of scFv/TM therapy of LPS/hyperoxia injury;
Aim 2 : Refine scFv/TM variants with precisely controlled selective activities;
Aim 3 : Define scFv/TM-EPCR cooperativity. This study will uncover molecular mechanisms of scFv/TM functions and guide design of targeted TM therapeutics tailored for selective treatment of inflammation or/and thrombosis in acute pulmonary and, likely, other diseases.

Public Health Relevance

Current treatment of the pathological conditions involving thrombosis and inflammation in lung diseases, including acute lung injury, hyperoxia, sepsis and ischemia/reperfusion are insufficient. We have designed a new agent comprising the endothelial anti-inflammatory and anti-thrombotic protein thrombomodulin (TM) genetically fused with an antibody fragment that anchors TM onto the endothelium. In this grant application we will study this novel agent and its proposed iterations in cell cultures and lab animals, in order to: i) dissect the mechanisms of its protective activities in lung diseases;and, ii) develop a novel specific and safe treatment for these diseases.

National Institute of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
Research Project (R01)
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Study Section
Lung Injury, Repair, and Remodeling Study Section (LIRR)
Program Officer
Moore, Timothy M
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University of Pennsylvania
Schools of Medicine
United States
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Carnemolla, Ronald; Villa, Carlos H; Greineder, Colin F et al. (2017) Targeting thrombomodulin to circulating red blood cells augments its protective effects in models of endotoxemia and ischemia-reperfusion injury. FASEB J 31:761-770
Greineder, Colin F; Hood, Elizabeth D; Yao, Anning et al. (2016) Molecular engineering of high affinity single-chain antibody fragment for endothelial targeting of proteins and nanocarriers in rodents and humans. J Control Release 226:229-37
Greineder, Colin F; Brenza, Jacob B; Carnemolla, Ronald et al. (2015) Dual targeting of therapeutics to endothelial cells: collaborative enhancement of delivery and effect. FASEB J 29:3483-92
Howard, Melissa; Zern, Blaine J; Anselmo, Aaron C et al. (2014) Vascular targeting of nanocarriers: perplexing aspects of the seemingly straightforward paradigm. ACS Nano 8:4100-32
Carnemolla, Ronald; Greineder, Colin F; Chacko, Ann-Marie et al. (2013) Platelet endothelial cell adhesion molecule targeted oxidant-resistant mutant thrombomodulin fusion protein with enhanced potency in vitro and in vivo. J Pharmacol Exp Ther 347:339-45
Greineder, Colin F; Chacko, Ann-Marie; Zaytsev, Sergei et al. (2013) Vascular immunotargeting to endothelial determinant ICAM-1 enables optimal partnering of recombinant scFv-thrombomodulin fusion with endogenous cofactor. PLoS One 8:e80110
Greineder, Colin F; Howard, Melissa D; Carnemolla, Ronald et al. (2013) Advanced drug delivery systems for antithrombotic agents. Blood 122:1565-75
Zaitsev, Sergei; Kowalska, M Anna; Neyman, Michael et al. (2012) Targeting recombinant thrombomodulin fusion protein to red blood cells provides multifaceted thromboprophylaxis. Blood 119:4779-85
Carnemolla, Ronald; Patel, Kruti Rajan; Zaitsev, Sergei et al. (2012) Quantitative analysis of thrombomodulin-mediated conversion of protein C to APC: translation from in vitro to in vivo. J Immunol Methods 384:21-4
Chacko, Ann-Marie; Nayak, Madhura; Greineder, Colin F et al. (2012) Collaborative enhancement of antibody binding to distinct PECAM-1 epitopes modulates endothelial targeting. PLoS One 7:e34958

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