Lymphoid adhesion promotes human thymic epithelial cell survival via NF-(kappa)B activation.
Inside the thymus, thymic epithelial cells and thymocytes show an interdependent relationship for their functional differentiation and development. As regards possible interdependency for their mutual survival, it is clear that lympho-epithelial adhesion can control the survival of developing thymocytes whereas the effects of lymphoid adhesion on epithelial cell survival have never been described. To address this issue, we performed co-cultures between normal human thymic epithelial cells (TEC) and a mature lymphoid T cell line (H9) or unfractionated thymocytes. TEC were induced to apoptosis by growth factor deprivation and the level of cell death was measured by flow cytometry. TEC stimulated by cell adhesion showed a significant reduced apoptosis when compared to the control and this phenomenon was associated with increased binding activity of NF-(kappa)B, as measured by gel shift analysis. The activation of NF-(kappa)B was necessary to promote survival, since its inhibition by acetyl salicylic acid prevented the promoting effect. The mAb-mediated crosslinking of (alpha)(3)(beta)(1) was considered as a potential inducer of TEC survival, since we have previously demonstrated that the engagement of this integrin was able to induce NF-(kappa)B activation in TEC. The crosslinking of (alpha)(3)(beta)(1), which clustered at the lympho-epithelial contact sites, partially reproduced the promoting activity of cell adhesion. These results highlight that lympho-epithelial adhesion can control the survival of thymic epithelial cells through an intracellular pathway which requires the activation of NF-(kappa)B and is triggered by integrins of the (beta)(1) family.
Scupoli
M T
MT
Department of Pathology, Section of Immunology, University of Verona, Italy. mariat@borgoroma.univr.it.
Fiorini
E
E
Marchisio
P C
PC
Poffe
O
O
Tagliabue
E
E
Brentegani
M
M
Tridente
G
G
Ramarli
D
D
D015703:Antigens, CD / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects; D001241:Aspirin / Q000494:pharmacology; D002448:Cell Adhesion / Q000187:drug effects; D002460:Cell Line; D048429:Cell Size / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D018920:Coculture Techniques; D004247:DNA / Q000235:genetics / Q000378:metabolism; D019281:Dimerization; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D006133:Growth Substances / Q000172:deficiency / Q000502:physiology; D006801:Humans; D039422:Integrin alpha3; D039201:Integrin alpha3beta1; D019012:Integrin beta1 / Q000378:metabolism; D016023:Integrins / Q000378:metabolism; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D016329:Sp1 Transcription Factor / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D013950:Thymus Gland / Q000166:cytology*
D015703:Antigens, CD; D006133:Growth Substances; D039422:Integrin alpha3; D039201:Integrin alpha3beta1; D019012:Integrin beta1; D016023:Integrins; D016328:NF-kappa B; D016329:Sp1 Transcription Factor; D004247:DNA; D001241:Aspirin