Enhanced platelet adhesion induces angiogenesis in intestinal inflammation and inflammatory bowel disease microvasculature.
Although angiogenesis is viewed as a fundamental component of inflammatory bowel disease (IBD) pathogenesis, we presently lack a thorough knowledge of the cell type(s) involved in its induction and maintenance in the inflamed intestinal mucosa. This study aimed to determine whether platelet (PLT) adhesion to inflamed intestinal endothelial cells of human origin may favour angiogenesis. Unstimulated or thrombin-activated human PLT were overlaid on resting or tumour necrosis factor (TNF)-α-treated human intestinal microvascular endothelial cells (HIMEC), in the presence or absence of blocking antibodies to either vascular cell adhesion molecule (VCAM)-1, intercellular adhesion molecule (ICAM)-1, integrin α(v)β(3) , tissue factor (TF) or fractalkine (FKN). PLT adhesion to HIMEC was evaluated by fluorescence microscopy, and release of angiogenic factors (VEGF and soluble CD40L) was measured by ELISA. A matrigel tubule formation assay was used to estimate PLT capacity to induce angiogenesis after co-culturing with HIMEC. TNF-α up-regulated ICAM-1, α(v)β(3) and FKN expression on HIMEC. When thrombin-activated PLT were co-cultured with unstimulated HIMEC, PLT adhesion increased significantly, and this response was further enhanced by HIMEC activation with TNF-α. PLT adhesion to HIMEC was VCAM-1 and TF independent but ICAM-1, FKN and integrin α(v)β(3) dependent. VEGF and sCD40L were undetectable in HIMEC cultures either before or after TNF-α stimulation. By contrast, VEGF and sCD40L release significantly increased when resting or activated PLT were co-cultured with TNF-α-pre-treated HIMEC. These effects were much more pronounced when PLT were derived from IBD patients. Importantly, thrombin-activated PLT promoted tubule formation in HIMEC, a functional estimate of their angiogenic potential. In conclusion, PLT adhesion to TNF-α-pre-treated HIMEC is mediated by ICAM-1, FKN and α(v)β(3) , and is associated with VEGF and sCD40L release. These findings suggest that inflamed HIMEC may recruit PLT which, upon release of pro-angiogenic factors, actively contribute to inflammation-induced angiogenesis.
Department of Hematology, Catholic University Medical School, Rome, Italy.
Sergio
S
Rutella
Stefania
S
Vetrano
Carmen
C
Correale
Cristina
C
Graziani
Andreas
A
Sturm
Antonino
A
Spinelli
Raimondo
R
De Cristofaro
Alessandro
A
Repici
Alberto
A
Malesci
Silvio
S
Danese
D001792:Blood Platelets / Q000166:cytology / Q000378:metabolism*; D023201:CD40 Ligand / Q000378:metabolism; D002478:Cells, Cultured; D054428:Chemokine CX3CL1 / Q000378:metabolism; D018920:Coculture Techniques; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007249:Inflammation / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D015212:Inflammatory Bowel Diseases / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D039302:Integrin alphaVbeta3 / Q000378:metabolism; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D007422:Intestines / Q000098:blood supply / Q000473:pathology; D008297:Male; D008856:Microscopy, Fluorescence; D055806:Microvessels / Q000378:metabolism* / Q000473:pathology; D009389:Neovascularization, Pathologic / Q000503:physiopathology; D010973:Platelet Adhesiveness / Q000502:physiology*; D013925:Thromboplastin / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
D054428:Chemokine CX3CL1; D039302:Integrin alphaVbeta3; D014409:Tumor Necrosis Factor-alpha; D019010:Vascular Cell Adhesion Molecule-1; D042461:Vascular Endothelial Growth Factor A; D018799:Intercellular Adhesion Molecule-1; D023201:CD40 Ligand; D013925:Thromboplastin