Transforming growth factor beta 1 null mutation in mice causes excessive inflammatory response and early death.

Abstract

To delineate specific developmental roles of transforming growth factor fPI (TGF-P1) we Five distinct TGF-P3 genes have been identified in vertebrates and three of these (TGF-f31, TGF-p2, and TGF-(33) are expressed in mammals. Each of the three isoforms has been highly conserved throughout evolution, suggesting specific roles for each (1, 2). These three isoforms share a high degree of amino acid sequence homology in the mature domain, are often coexpressed and colocalized, and have qualitatively similar actions on tissue culture cells (1, 2). Therefore, it has been difficult to define the precise biological role ofindividual TGF-3 isoforms. To delineate and define the specific in vivo role of TGF-f31, we disrupted the murine TGF-,B1 gene in embryonic stem (ES) cells by homologous recombination (for reviews, see refs. 10 and 11). The targeted cells were subsequently used to generate mice with a loss-of-function mutation at the TGF-381 locus. Although the TGF-f31 null mutation in the homozygous state causes some intrauterine lethality, more than one-third of the fetuses develop to term and appear clinically normal at birth. After 2 weeks these mice develop a wasting syndrome and die -1-2 weeks later. Massive inflammatory lesions are seen in many organs, including the lungs (vasculitis, perivascular cuffing, and interstitial pneumonia) and heart (endocarditis and myocarditis), suggesting an uncontrolled inflammatory response that leads to premature death.MATERIALS AND METHODS Constructs. A 5.7-kb Bgl II genomic fragment containing the first two exons of TGF-,31 from the previously described clone pB2 (12) was subcloned into the modified Bluescript KS vector (Stratagene) in which the Asp 718 site was converted to a Sfi I site to generate pB2-3. A 560-bp sequence spanning part of the first exon (154 bp of coding sequence) and intron was deleted following Asp 718 digestion of pB2-3, and the phosphoglycerate kinase (PGK)-neomycin resistance (neo) gene (13) was inserted. The targeting vector, pTC-1, also contained a PGK-driven herpes simplex virus thymidine kinase gene (PGK-HSVtk) at the 3' end (see Fig. 1). Both marker genes also contain PGK poly(A) signals (13).ES Cell Culture, Transfection, and Selection. The CCE ES cell line (a generous gift from E. Robertson, Columbia University) was cultured on mitomycin-treated STO feeder layers in Dulbecco's modified Eagle medium supplemented with 10% fetal calf serum (HyClone) and 10%o newborn calf serum (GIBCO) as described (14). ES cells were grown to 70% confluency, trypsinized, and resuspended in phosphatebuffered saline (PBS; Ca2+ and Mg2+ free) at 107 cells per ml.

TGF‐β regulates pathology but not tissue CD8+ T cell dysfunction during experimental Trypanosoma cruzi infection

“…TGF-b plays a critical role in collagen formation and extracellular matrix deposition in addition to its role in down-regulating T cell responses [5]. Consequently, TGF-b -/-mice exhibit approximately 50% embryonic lethality and live-born TGF-b -/-mice develop multiorgan inflammation, primarily in the heart and lung, and die within 2-3 weeks of birth [7]. The early lethality of TGF-b -/-mice makes this an unsuitable model in which to study infectious diseases.…”

Transforming growth factor-β1 is the predominant isoform required for breast cancer cell outgrowth in bone

“…Thus, we investigated whether expression of the neutralizing ligand trap could blunt TGF-b-induced expression of these two factors. Vector control (VC) or Fc:TbRII(ECD)-expressing MDA-MB-231 breast cancer cells were allowed to condition serum free media for 48 h and subsequently incubated in the absence or presence of TGF-b1 for a further 3 h. Quantitative Loss or reduction of TGF-b1 levels in host-derived tissue prevents the efficient establishment of breast cancer cells in bone To specifically interrogate the importance of bonederived TGF-b1 on the ability of breast cancer cells to form osteolytic lesions, we used TGF-b1-deficient mice that were bred onto a RAG2-deficient background (Engle et al, 1999), which rescues the early lethality observed in TGF-b1-null mice due to widespread inflammatory disease (Shull et al, 1992;Kulkarni et al, 1993). To ensure that the RAG2À/À mice permitted xenografting of human breast cancer cells, we injected an MDA-MB-231 variant that aggressively metastasizes to bone (1833-TR cells) into mammary fat pads of RAG2À/À mice (Kang et al, 2003;Minn et al, 2005).…”

TGF‐β1 production by CD4+CD25+ regulatory T cells is not essential for suppression of intestinal inflammation

“…TGF-b1 is a potently suppressive cytokine that plays a critical role in the regulation of immune function, as illustrated by the development of a severe autoimmunelike syndrome in TGF-b1 -/-mice [11,12]. Genetic disruption of TGF-b signaling in T cells by overexpression of a dominant-negative TGF-b type II receptor (DNRIITg), conditional deletion of the TGF-b type II receptor, or inactivation of the gene encoding Smad3, alters the sensitivity of T cells to the inhibitory effects of TGF-b and leads to aberrant T cell responses [13][14][15].…”

“…While CD4 + CD25 + Treg cells from IL-4 -/-and IL-10 -/-mice are as effective as WT CD4 + CD25 + T cells in mediating suppression of AIG, CD4 + CD25 + Treg cells from IL-10 -/-mice cannot control IBD induced by antigen-experienced effector T cells [8,9]. Similarly, IL-10 -/-CD4 + CD25 + Treg cells, in contrast to WT cells, fail to attenuate effector T cell responses to Leishmania major in resistant C57BL/6 mice [10].TGF-b1 is a potently suppressive cytokine that plays a critical role in the regulation of immune function, as illustrated by the development of a severe autoimmunelike syndrome in TGF-b1 -/-mice [11,12]. Genetic disruption of TGF-b signaling in T cells by overexpression of a dominant-negative TGF-b type II receptor (DNRIITg), conditional deletion of the TGF-b type II receptor, or inactivation of the gene encoding Smad3, alters the sensitivity of T cells to the inhibitory effects of TGF-b and leads to aberrant T cell responses [13][14][15].…”

“…Thus, it is possible that the very slight increase in intestinal inflammation observed in groups receiving TGF-b1 -/-compared to WT Treg cells is not exclusively due to contaminating effector T cells, but instead result at least in part from a lack of TGF-b1 signaling in Treg cells and consequential fading of CD4 + CD25 + Treg cell function over time. Although CD4 + CD25 + T cells from Smad3 -/-mice appeared to function as efficiently as WT CD4 + CD25 + T cells in our colitis model, it remains possible that TGF-b could play a stimulatory role in the induction of CD4 + CD25 + suppressor activity, perhaps in a Smad3-independent fashion [16].To assess CD4 + CD25 + Treg cell function in TGF-b1 -/-mice, it is essential to isolate these cells from neonatal asymptomatic mice, as TGF-b1 -/-animals develop a multi-organ autoimmune phenotype by 3-5 wk of age [11,12]. In this study, TGF-b1 -/-CD4 + CD25 + T cells from 3-to 10-day-old neonatal mice were functionally comparable to WT mice, and the expression of activation markers on total CD4 + CD25 + T cells from these two strains was comparable (data not shown), confirming our previous observation [16].…”