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Heparin- and cell-binding sequences of fibronectin peptides (FN) induced in transforming growth factor beta1 (TGF-beta1) prevents adhesion of leukocytes to vascular endothelial cells and eliminates cardiopulmonary and inflammation diseases in mice. The FN peptides react with cell surface proteoglycans and integrins of beta1 complex to reduce infiltration of inflammatory cells into heart and lungs of TGF-beta1 injected mice.

Impaired wound healing states lead to substantial morbidity and cost with treatment resulting in an expenditure of billions of dollars per annum in the US alone. Both chronic wounds and impaired acute wounds are characterized by excessive inflammation, enhanced proteolysis, and reduced matrix deposition. These confounding factors are exacerbated in the elderly, in part, as we report here, related to increased local and systemic tumor necrosis factor-alpha ( TNF-α) levels. Moreover, we have used a secretory leukocyte protease inhibitor ( SLPI) null mouse model of severely impaired wound healing and excessive inflammation, comparable to age-related delayed human healing, to demonstrate that topical application of anti- TNF-α neutralizing antibodies blunts leukocyte recruitment and NFκB activation, alters the balance between M1 and M2 macrophages, and accelerates wound healing. Following antagonism of TNF-α, matrix synthesis is enhanced, associated with suppression of both inflammatory parameters and NFκB binding activity. Our data suggest that inhibiting TNF-α is a critical event in reversing the severely impaired healing response associated with the absence of SLPI, and may be applicable to prophylaxis and/or treatment of impaired wound healing states in humans. [ABSTRACT FROM AUTHOR]

Innate and adaptive immunity function to eliminate foreign invaders and respond to injury while enabling coexistence with commensal microbes and tolerance against self and innocuous agents. Although most often effective in accomplishing these objectives, immunologic processes are not fail-safe and may underserve or be excessive in protecting the host. Checks and balances to maintain control of the immune system are in place and are becoming increasingly appreciated as targets for manipulating immunopathologic responses. One of the most recognized mediators of immune regulation is the cytokine transforming growth factor-beta (TGF-beta), a product of immune and nonimmune cells. Emerging data have unveiled a pivotal role for TGF-beta as a perpetrator of suppression by CD4(+)CD25(+) regulatory T (Treg) cells and in apoptotic sequelae. Through its immunosuppressive prowess, TGF-beta effectively orchestrates resolution of inflammation and control of autoaggressive immune reactions by managing T cell anergy, defining unique populations of Treg cells, regulating T cell death, and influencing the host response to infections.

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.

Deficiency of TGF-beta1 is associated with immune dysregulation and autoimmunity as exemplified by the multifocal inflammatory lesions and early demise of the TGF-beta1 null mice. Elevated NO metabolites (nitrite and nitrate) in the plasma of these mice suggest a participatory role of NO in the pathogenic inflammatory response. To determine the mechanism for this dysregulation, we examined upstream elements that could contribute to the overexpression of NO, including inducible NO synthase (iNOS) and transcription factors Stat1alpha and IFN-regulatory factor-1 (IRF-1). The coincident up-regulation of IFN-gamma, an iNOS inducer, and iNOS, before the appearance of inflammatory lesions, suggests that failed regulation of the IFN-gamma signaling pathway may underlie the immunological disorder in TGF-beta1 null mice. In fact, IFN-gamma-driven transcription factors IRF-1 and Stat1alpha, both of which act as transcriptional activators of iNOS, were elevated in the null mice. Treatment of mice with a polyclonal anti-IFN-gamma Ab reduced expression and activity not only of transcription factors Stat1alpha and IRF-1 but also of iNOS. Furthermore, anti-IFN-gamma treatment delayed the cachexia normally seen in TGF-beta1 null mice and increased their longevity. The global nature of immune dysregulation in TGF-beta1 null mice documents TGF-beta1 as an essential immunoregulatory molecule.