| First Author | McCartney-Francis N | Year | 2004 |
| Journal | J Immunol | Volume | 172 |
| Issue | 6 | Pages | 3814-21 |
| PubMed ID | 15004187 | Mgi Jnum | J:88604 |
| Mgi Id | MGI:3036375 | Doi | 10.4049/jimmunol.172.6.3814 |
| Citation | McCartney-Francis N, et al. (2004) Aberrant Toll receptor expression and endotoxin hypersensitivity in mice lacking a functional TGF-beta 1 signaling pathway. J Immunol 172(6):3814-21 |
| abstractText | TGF-beta1 plays a central role in maintaining normal immune function and deficiency of this potent immunosuppressive molecule is linked to uncontrolled inflammation, cachexia, and multiorgan failure as seen in the TGF-beta1 null mouse. Infiltration of inflammatory cells into vital organs of the null mouse is accompanied by increased gene expression of inflammatory cytokines, including TNF-alpha and IL-1beta, as well as inducible NO synthase, each regulated by NF-kappaB. Treatment with the proteasome inhibitor MG132 to prevent NF-kappaB activation dramatically reduced NO production and expression of inflammatory cytokines. This inflammatory phenotype with NF-kappaB activation in the TGF-beta1 null mouse, in the absence of any identifiable pathogen, suggested activation of innate immune responses. Because Toll-like receptors (TLR) are essential in the activation of innate immunity, we examined inflamed tissue from TGF-beta1 null and wild-type mice for expression of TLR4, the receptor that interacts with bacterial cell wall LPS to initiate an NF-kappaB-dependent signaling pathway, leading to gene transcription of inflammatory mediators. Increased TLR4 mRNA expression observed in TGF-beta1 null mice as well as in mice lacking the TGF-beta transcription factor Smad3 was associated with LPS hyperresponsiveness leading to increased expression of inflammatory cytokines and NO and endotoxemia. Furthermore, mice lacking both TGF-beta1 and a functional TLR4 were resistant to endotoxin shock. Constitutive and/or environmental activation of TLR4 and downstream elements, in the absence of TGF-beta suppression, may impact on innate and adaptive immunity and contribute to massive uncontrolled inflammation. |
