Main results

 

1.   Angiogenesis in IBD

One of the most novel aspects that directly implicate endothelial participation in inflammation is the process of angiogenesis, and our laboratory has been the first to show that robust angiogenesis occurs in both forms of IBD and that starving the inflamed gut by angiogenesis inhibition can be an entirely new therapeutic approach to treat IBD. This area of investigation is in collaboration with Claudio Fiocchi at the Cleveland Clinic, OHIO, USA.

 

2.   The lymphatic system in IBD

The lymphatic system has received little or no attention in the investigation of IBD pathogenesis. Our laboratory has isolated for the first time primary human lymphatic intestinal endothelial cells and is now studying how promotion of lymphatic function can be a new therapeutic approach to drein leukocytes away from the gut to the lymphonodes. This area of investigation is in collaboration with Elisabetta Dejana at the Institute of molecular oncology, Milan, Italy.

 

3.   The epithelial barrier in IBD and inflammation associated colon cancer

Our laboratory has studied the role of junctional adhesion molecule-1 (JAM-1) in governing the integrity of epithelial barrier function. Our laboratory has successfully shown that JAM-1 is a new molecule involved in IBD pathogenesis by controlling intestinal permeability and epithelial barrier integrity. In addition, we are now investigating the role of JAM-1 in controlling inflammation-associated cancer growth. This area of investigation is in collaboration with Elisabetta Dejana at the Institute of molecular oncology, Milan, Italy.

 

4.   Coagulation as a new component of IBD pathogenesis

The protein C pathway is a system broadly involved in coagulation that has recently been shown to play a role in controlling microvascular inflammation. Our laboratory has shown that the protein C pathway plays a crucial role in governing microvascular inflammation that underlies IBD associated inflammation, and that restoring the protein C activity is a new therapeutic approach for IBD. In addition, we have recently shown that the PC system is expressed surprisingly at epithelial site in the gut, and plays an entirely new and unexpected role in governing barrier function and tollerance by dendritic cells. This area of investigation is in collaboration with Frank CAstellino at the University of Notredame, IL, USA.

 

5.   Decoy receptors in IBD and inflammation associated colon cancer

D6 is a decoy receptor that has been fully caractherized by A. Manovani. In collaboration with his group and using the tolls available like KO models and specific antibodies, we have shown that D6 is a new molecule that plays a role in governing intestinal homeostasis by scavanging inflammatory chemokines. In addition, for the first time we have provided evidence that D6 and chemokines play a role in the promotion of colon cancer associated with IBD.

 

Main objectives and research lines

 

Our laboratory focuses mainly in investigating the mechanisms of inflammatory bowel disease (IBD) patogenesis and inflammation associated colon cancer. The main areas of active investigation at the moment are:

 

1.   Angiogenesis in IBD

This project will test the following central hypothesis: Angiogenesis is a critical component of IBD and contributes to disease pathogenesis. This hypothesis will be tested by four specific aims:

Aim 1 . Obtain evidence of increased vascularization and endothelial cell activation in IBD mucosa:

· quantitative analysis of vessel density;

·   mucosal endothelial cell integrin expression and modulation;

·   analysis of HIMEC gene expression by microarray technology.

Aim 2 . Define the dominant angiogenic factors produced in IBD, their origin, and biological activity:

·   detection of pro- and anti-angiogenic factors in normal and IBD intestine;

·  i dentification of their cellular sources;

·   demonstration of increased pro-angiogenic bioactivity in IBD intestine.

Aim 3 . Characterize endothelial cell-mediated changes in the ECM that promote angiogenesis: 

· recruitment of ECM-degrading leukocytes by HIMEC;

·   demonstration of matrix-degrading enzymatic activity in IBD;

·   assessment of HIMEC pro-angiogenic response to hyaluronan (HA) fragments.

Aim 4 . Investigate the effects of anti-angiogenic compounds in models of IBD: 

·   effect of anti-angiogenic therapy in prevention and treatment of experimental colitis;

·   evaluation of intestinal vascularization during anti-angiogenic therapy;

·   effect of pro-angiogenic agents on progression of colitis

 

2. The lymphatic system in IBD

This project will test the following specific hypothesis:

Lymphangiogenesis is a critical new component of IBD pathogenesis and its blockade may offer a new therapeutic approach for IBD. This hypothesis will be tested by three specific aims:

Aim 1. Obtain evidence of increased lymphangiogenesis and define the dominant lymphangiogenic factors produced in IBD mucosa: This will include:

·   quantitative analysis of lymphatic vessel density and morphometry;

·   detection of pro-lymphangiogenic factors in normal and IBD intestine,

·   identification of their cellular sources.

Aim 2 . Define in vitro the functional role of human intestinal lymphatic endothelial cells (HILEC): This will include:

·   isolation and functional characterization of HILEC;

·   investigation in vitro of lymphangiogenesis; 

·   role of HILEC in mediating leukocyte in vitro trafficking.

Aim 3.  Investigate the effects of anti-lymphangiogenic compounds in models of IBD: This will include:

·   evaluation of the effect of anti-lymphangiogenic therapy in prevention and treatment of experimental IBD;

·   assessment of intestinal lymphatic vascularization during anti-lymphangiogenic therapy;

·   study of the effect of pro-lymphogenic agents on progression of colitis

 

 

3.   The epithelial barrier in IBD and inflammation associated colon cancer

This project investigates the role of junctional adhesion molecule-1 (JAM-1) in governing the integrity of epithelial barrier function, and in particular on its role in controlling intestinal permeability and epithelial barrier integrity. In addition, we are now investigating the role of JAM-1 in controlling inflammation-associated cancer growth using the APC model of colon cancer.

 

4.   Coagulation as a new component of IBD pathogenesis

This project aims to investigate the following central hypothesis: The protein C pathway is expressed by DC and epithelial cells, and mediates a novel cell-cell cross-talk that is necessary for intestinal homeostasis.  

This hypothesis will be tested in two specific aims:

Aim 1. Study the expression and function of the TM-activated PC-EPCR pathway in human IBD. This will include: a) investigating the expression of TM, EPCR, PAR-1 and PC in intestinal DC and the epithelium, both in vivo and in vitro; and b) studying the functional role of the PC system in human DC and epithelial cells in vitro.

Aim 2 . Investigate the functional role of the PC pathway in mediating epithelial homeostasis in a dendritic cell-dependent manner in a model of IBD. This will include: a) investigating the expression of TM and EPCR by mucosal DC, and of PAR-1 and PC by epithelial cells in healthy and colitic models; b) investigating the functional role played by DC in mediating the conversion of PC into activated PC, in models with experimentally induced colitis; and c) testing the efficacy of topical administration of recombinant activated PC for the treatment of experimental colitis.

 

5.   The role of platelets in promoting colon cancer

This project will test the following specific hypothesis: Activated platelets critically contribute to colon cancer growth by promotion of angiogenesis.

This hypothesis will be tested by 2 specific aims:

Aim 1 . Assessment of platelet activation state and angiogenesis promotion in colon cancer patients during platelet-endothelial interactions:

·   Quantitative analysis of platelet activation state in normal and colon cancer patients;

·   Quantitative analysis of angiogenesis and endothelial platelet ligands in normal and colon cancer patients;

·   Evaluation of molecules and pro-angiogenic factors generated during platelet-endothelium interactions;

·   Demonstration of platelets' pro-angiogenic bioactivity on the intestinal tumor microvasculature.

Aim 2 . Investigate the effects of inhibiting platelet activity and interaction with the tumor microvasculature in models of colon cancer:

a) Effect of platelet depletion in an experimental model of inflammation-associated colon cancer;

b) Effect of anti-platelet drug in colon cancer formation in models of colon cancer;

c) Evaluation of the CD40/CD40L pathway manipulation in colon cancer associated angiogenesis and in platelet-driven angiogenesis.

 

6. Mechanisms of stem cell homing to the gut in intestinal inflammation.

The aim of our project is to assess the therapeutic efficacy of SC transplantation in experimental IBD and to investigate the molecules that orchestrate SC recruitment to the intestine.

We will investigate the following central hypothesis: nonmyeloablative SC therapy is an effective therapeutic approach for experimental IBD and SC are actively recruited by the inflamed intestinal microvasculature in IBD. This will include:

Aim 1 : Investigate the therapeutic efficacy of nonmyeloablative SC therapy in different models of IBD.

Aim 2: Investigate the adhesion molecules and chemokines that mediate SC homing to the inflamed intestinal microvasculature in experimental IBD.

·  a ssessment of the role of major cell adhesion molecule (CAM) in mediating SC adhesion to intestinal microvasculature;

·   investigation of the major chemokines involved in SC chemoattraction to the intestine;

·   assessment of SC integrins and their manipulation in order to enhance SC adhesion to the inflamed intestinal endothelium.

Aim 3 : Investigate the adhesion molecules and chemokines that mediate SC adhesion to the inflamed human intestinal microvascular endothelial cells (HIMEC).

·   assessment of the major CAM mediating SC adhesion to HIMEC;

·   investigation of the major chemokines involved in SC chemoattraction to the intestine;

·   assessment of SC integrins and their manipulation in order to enhance SC adhesion to HIMEC.

 

Several models of IBD will be used in a complementary manner in order to test the beneficial effects of SC treatment for IBD. This complementary approach will be needed to clarify the effectiveness of SC therapy, by using models resembling both CD and UC. Moreover, the homing of SC to the intestine will be investigated in order to shed light on the major molecules involved in such a process. Finally, by exploring a possible enhancement of human SC adhesion to HIMEC, it would be possible to translate to humans the knowledge gathered from experimental models studies, thus optimizing SC treatment for IBD.

We expect that SC therapy would be an effective therapeutic approach for IBD, as assessed by the reduction of inflammatory disease scores, such as histopathological and clinical colitis scores. We also expect to define the major CAM and chemokines that mediate SC adhesion and recruitment to the inflamed intestine in experimental IBD, and we will try to optimize their recruitment to the intestine by up-regulating selective integrins on SC. Finally, we would try to translate the knowledge derived from models' experiments in human in vitro studies, thus paving the way for interventional clinical trials in human IBD by using SC therapy.

 

In addition, we are involved in national and international clinical trials, and in studies as single center in patients with IBD.