Transforming growth factor-beta 1 in diabetic nephropathy

In diabetic nephropathy the extent of matrix accumulation in both glomeruli and the interstitium correlates strongly with the degree of renal insufficiency and proteinuria. Factors responsible for the deposition and accumulation of extra cellular matrix material within the kidney are therefore of considerable interest. Such factors include the potent fibrotic cytokine TGF-beta. We measured serum TGF-beta1 in patients with various stages of diabetic nephropathy, and correlated its level with different biochemical parameters. The study was conducted on: Group I: 30 patients with diabetic nephropathy (Subgroup IA: 20 patients with microalbuminuria; Subgroup IB: 10 patients with overt nephropathy), Group II: 19 diabetic patients without nephropathy (positive control), Group III: 20 healthy volunteers (negative control). Serum creatinine, Fasting and postprandial blood glucose, Fasting serum cholesterol, Glycated haemoglobin (HbA1c), Microalbumin estimation in urine, Serum TGF-beta1 estimation were done for all the studied groups. Our results showed a statistically significantly higher serum TGF-beta1 level in patients with diabetic nephropathy versus diabetic patients without nephropathy (mean +/- SD, 47.66 +/- 21.92 and 27.07 +/- 15.46 respectively) (P<0.001). Also in patients with diabetic nephropathy versus healthy controls (mean +/- SD, 47.66 +/- 21.29 and 27.05 +/- 8.95 respectively) (P<0.001). While serum TGF-beta1 concentrations were almost similar in diabetic patients without nephropathy and in healthy controls. Serum TGF-beta1 was statistically significantly higher in patients with overt nephropathy versus patients with microalbuminuria (mean+/-SD, 73.5 +/- 2.41 and 34.9 +/- 12.41) (P<0.001). Serum TGF-beta1 was significantly positively correlated with albumin excretion rate, fasting and postprandial blood glucose levels, serum cholesterol and HbA1c, these correlations were only found in diabetic patients with nephropathy but not in those without nephropathy or the control group. (r=0.86, P<0.001, r=0.444, P<0.05, r=0.375, P<0.05, r=0.532, P <0.01, r=0.696, P<0.001 respectively. HbA1c was found to be predictor of 68% of changes of serum TGF-beta1 (P<0.001) and serum cholesterol was predictor of 73% of changes of serum TGF-beta1 concentration (P<0.01). In conclusion, our results suggest that TGF-beta1 may play a key role in the development and progression of diabetic nephropathy. Accordingly, it may be also directly implicated in the functional deterioration of the kidney functions seen in patients with diabetic nephropathy, therefore beside proper glycemic control, strategies aiming at antagonizing TGF- beta1 for example by the use of specific antibodies or a specific inhibitor of TGF-beta1 may help to prevent the development or attenuate the progression of nephropathy in diabetic patients.     

Role of transforming growth factor-beta1-smad signal transduction pathway in patients with hepatocellular carcinoma

AIM:To explore the role of transforming growth factor-beta1(TGF-β1)-smad signal transduction pathway inpatients with hepatocellular carcinoma.METHODS:Thirty-six hepatocellular carcinoma speci-mens were obtained from Qidong Liver Cancer Instituteand Department of Pathology of the Second AffiliatedHospital of Nanjing Medical University.All primary anti-bodies(polyclonal antibodies)to TGF-β1,type Ⅱ Trans-forming growth factor-beta receptor(TβR-Ⅱ),nuclear fac-tor-kappaB(NF-KB),CD34,smad4 and smad7,secondaryantibodies and immunohistochemical kit were purchasedfrom Zhongshan Biotechnology Limited Company(Bei-jing,China).The expressions of TGF-β1,TβR-Ⅱ,NF-kB,smad4 and smad7 proteins in 36 specimens ofhepatocellular carcinoma(HCC)and its adjacent tissuewere separately detected by immunohistochemistry toobserve the relationship between TGF-β1 and TβR-Ⅱ,between NF-kB and TGF-β1,between smad4 and smad7and between TGF-β1 or TβR-Ⅱ and microvessel density(MVD).MVD was determined by labelling the vesselendothelial cells with CD34.RESULTS:The expression of TGF-β1,smad7 and MVDwas higher in HCC tissue than in adjacent HCC tissue(P<0.01,P<0.05,P<0.01 respectively).The expressionof TβR-Ⅱ and smad4 was lower in HCC tissue than in its adjacent tissue(P<0.01,P<0.05 respectively).Theexpression of TGF-β1 protein and NF-kB protein wasconsistent in HCC tissue.The expression of TGF-β1 andMVD was also consistent in HCC tissue.The expressionof TβR-Ⅱ was negatively correlated with that of MVD inHCC tissue.CONCLUSION:The expressions of TGF-β1,TβR-Ⅱ,NF-kB,smad4 and smad7 in HCC tissue,which are ma-jor up and down stream factors of TGF-β1-smad signaltransduction pathway,are abnormal.These factors areclosely related with MVD and may play an important rolein HCC angiogenesis.The inhibitory action of TGF-β1 isweakened in hepatic carcinoma cells because of abnor-mality of TGF-β1 receptors(such as TβR-Ⅱ)and postre-ceptors(such as smad4 and smad7).NF-kB may causeactivation and production of TGF-β1.     

Transforming growth factor-beta1 to the bone

TGF-beta1 is a ubiquitous growth factor that is implicated in the control of proliferation, migration, differentiation, and survival of many different cell types. It influences such diverse processes as embryogenesis, angiogenesis, inflammation, and wound healing. In skeletal tissue, TGF-beta1 plays a major role in development and maintenance, affecting both cartilage and bone metabolism, the latter being the subject of this review. Because it affects both cells of the osteoblast and osteoclast lineage, TGF-beta1 is one of the most important factors in the bone environment, helping to retain the balance between the dynamic processes of bone resorption and bone formation. Many seemingly contradictory reports have been published on the exact functioning of TGF-beta1 in the bone milieu. This review provides an overall picture of the bone-specific actions of TGF-beta1 and reconciles experimental discrepancies that have been reported for this multifunctional cytokine.     

Transforming growth factor-beta 1 and T-lymphocytes modulate the growth of human peripheral blood progenitor cells

This study examined the effects of transforming growth factor-beta 1 (TGF-beta 1) and autologous T-lymphocytes on the growth of day-14 granulocyte-monocyte progenitor cells (CFU-GM). Mononuclear cells from human peripheral blood were depleted of accessory cells, yielding "B/null" or "null" cell populations enriched 17-fold and 94-fold, respectively, for CFU-GM. Addition of TGF-beta 1 to B/null or null cells caused a dose-dependent decline in CFU-GM cloning efficiency. The addition of unstimulated autologous T cells to B/null or null cells enhanced CFU-GM growth both in the absence and presence of TGF-beta 1. T cells enhanced growth of all CFU-GM colony types to equal extents, whereas TGF-beta 1 inhibition preferentially reduced the proportion of macrophage colonies. TGF-beta 1 concentrations that blocked T-cell proliferation did not interfere with the capacity of T cells to enhance CFU-GM growth. The data suggest that noncycling T cells can reduce the inhibitory effects of TGF-beta 1, most likely through production of one or more stimulatory cytokines.     

Transforming growth factor-beta1 and activin A generate antiproliferative signaling in thyroid cancer cells

Transforming growth factor-beta 1 (TGF-beta1) and activin A (ActA) induce similar intracellular signaling mediated by the mothers against decapentaplegic homolog (SMAD) proteins. TGF-beta1 is a potent antimitogenic factor for thyroid follicular cells, while the role of ActA is not clear. In our study, the proliferation of TPC-1, the papillary thyroid carcinoma cell line, was reduced by both recombinant ActA and TGF-beta1. Due to the concomitant expression of TGF-beta1 and ActA in thyroid tumors, we investigated the effects of either TGF-beta1 or ActA gene silencing by RNA interference in TPC-1 cells in order to distinguish the specific participation of each in proliferation and intracellular signaling. An increased proliferation and reduced SMAD2, SMAD3, and SMAD4 mRNA expression were observed in both TGF-beta1 and ActA knockdown cells. Recombinant TGF-beta1 and ActA increased the expression of inhibitory SMAD7, whereas they reduced c-MYC. Accordingly, we detected a reduction in SMAD7 expression in knockdown cells while, unexpectedly, c-MYC was reduced. Our data indicate that both TGF-beta1 and ActA generate SMADs signaling with each regulating the expression of their target genes, SMAD7 and c-MYC. Furthermore, TGF-beta1 and ActA have an antiproliferative effect on thyroid papillary carcinoma cell, exerting an important role in the control of thyroid tumorigenesis.     

Transforming growth factor—β1in invasion and metastasis in colorectal cancer

AIM：To investigate the role of TGFβ1 in invasion and metastasis in colorectal cancer by analysing TGFβ1 correlated wity depth of tumor invasion,stage and metastasis.METHODS:Serum TGFβ1levels were determined in50patients with colorectal cancer and 30healthy volunteers using a TGFβ1 enzyme-linked immunosorbent assay.TGFβ1 expression in primary and lymph node metastatic lesions were detected in 98cases of colorectal cancer by immunohistochemical staining and in situ hybridization.RESULTS:Serum levels of TGFβ1 in patients with colorectal cancer(40&#177;18μg&#183;L^-1)were significantly higher than those in the healthy control group(19&#177;8μg&#183;L^-1),P&lt;0.05.Elevated levels of serum TGFβ1were found in 60%of patients with colorectal cancer when the mean+2s was used as the upper limit of the normal range(35.1μg&#183;L^-1).Increases in serum TGFβ1 levels were significantly asociated with Dukei‘s stage(P&lt;0.05),but there was no significant difference between,Duki‘s stage Bpatients and Dukei‘s stage Cpatients.In the cytoplasm of cancer cells,TGFβ1 was immunostained in37.8%(37/98)of colorectal cancer,and this expression was confirmed by in situ hybridization,Among35cases of colorectal cancer with lymph node metastatic lesions,TGFβ1 positive staining was found in18(51.4%)cases of primary tumor,and 25(71.4%)cases with lymph node metastatic lesions,respectively,Of17cases with no staining in the primary lesion.7(41.2%)casesshowed TGFβ1 staining in the metastatic lesion.Serum TGFβ1 levels and TGFβ1 expression in colorectal cancer tissues were correlated significantly with depth of tumor invasion,stage and metastasis,Patients in stage C-D,T3-T4and with metastasis had significantly higher TGFβ1 levels than patients in stage A-B,T1-T2and without metastasis(P&lt;0.05).CONCLUSION:These results suggest that transforming growth factor-β1 is closely related to the invasion and metastasis of colorectal cancer.It increased the invasive and metastatic potential of tumor by altering a tumor microenvironment.TGFβ1 may be used as a possible biomarke.     

Transforming growth factor-beta1 in supernatants from stored red blood cells inhibits neutrophil locomotion

Studies comparing transfusion and nontransfusion patients suggest an increased risk of postoperative infections in transfusion groups. Supernatants of blood components have been shown to affect the function of T lymphocytes and natural killer cells. Here, we found that supernatants from stored red blood cells (RBCs) inhibit human neutrophil migration in response to formyl peptides and stimulate neutrophil locomotion. These effects can be observed with high dilutions of RBC supernatants, such as 1:5 x 106 (vol/vol), able to trigger locomotion as well as desensitization of the cells to alternative chemoattractants. The phenomenon might be mediated by chemoattractants present in the supernatants. As RBC supernatants failed to mobilize intracellular free calcium, the chemoattractants should belong to the group of pure chemoattractants, that is, soluble Fas ligand (sFasL) and transforming growth factor-beta1 (TGF-beta1), known to act without increasing calcium levels. Recombinant TGF-beta1, but not sFasL, was found to reproduce the ability of RBC supernatants to both inhibit neutrophil response to formyl peptides and stimulate neutrophil locomotion. Moreover, TGF-beta1-immunodepleted supernatants did not display neutrophil-directed activities. Finally, RBC supernatants from RBCs stored after depletion of leukocytes were incapable of affecting neutrophil function. With neutrophils acting as a first-line antimicrobial defense, the ability, shown here, of high dilutions of RBC supernatants to inhibit neutrophil chemotaxis through TGF-beta1 may be a relevant determinant of infections in the postoperative period for transfusion patients. Consistently, the neutrophil chemotactic response to formyl peptide was inhibited by the plasma obtained from 5 transfusion patients.     

转化生长因子β和肺纤维化

转化生长因子β(transforming growth factor-β,TGF-β)是启动和终止炎症和组织修复的调节因子,是参与调控肺纤维化发生的细胞因子.TGF-β亚单位功能与其种类以及与受体的亲和力有密切关系.TGF-β的信号通路在纤维化的发生发展中起重要作用.     

Transforming growth factor-beta1 regulates macrophage migration via RhoA

Brief treatment with transforming growth factor (TGF)-beta1 stimulated the migration of macrophages, whereas long-term exposure decreased their migration. Cell migration stimulated by TGF-beta1 was markedly inhibited by 10 mug/mL Tat-C3 exoenzyme. TGF-beta1 increased mRNA and protein levels of macrophage inflammatory protein (MIP)-1alpha in the initial period, and these effects also were inhibited by 10 mug/mL Tat-C3 and a dominant-negative (DN)-RhoA (N19RhoA). Cycloheximide, actinomycin D, and antibodies against MIP-1alpha and monocyte chemoattractant protein-1 (MCP-1) abolished the stimulation of cell migration by TGF-beta1. These findings suggest that migration of these cells is regulated directly and indirectly via the expression of chemokines such as MIP-1alpha and MCP-1 mediated by RhoA in response to TGF-beta1. TGF-beta1 activated RhoA in the initial period, and thereafter inactivated them, suggesting that the inactivation of RhoA may be the cause of the reduced cell migration in response to TGF-beta1 at later times. We therefore attempted to elucidate the molecular mechanism of the inactivation of RhoA by TGF-beta1. First, TGF-beta1 phosphorylated RhoA via protein kinase A, leading to inactivation of RhoA. Second, wild-type p190 Rho GTPase activating protein (p190RhoGAP) reduced and DN-p190RhoGAP reversed the reduction of cell migration induced by TGF-beta, suggesting that it inactivated RhoA via p190 Rho GAP.     

Transforming growth factor-beta stimulates ascorbate transport activity in osteoblastic cells.

Transforming growth factor-beta (TGF beta) modulates the proliferation and differentiation of a number of cell types, including osteoblasts. TGF beta has been shown to stimulate matrix synthesis by connective tissue cells, but its mechanism of action is poorly understood. Because ascorbate (reduced vitamin C) also influences osteoblastic differentiation and is required as a cofactor for collagen synthesis, the present study examined the effect of TGF beta on osteoblastic ascorbate uptake. Saturable Na(+)-dependent uptake of ascorbate by cultures of UMR-106 rat osteosarcoma cells proceeded linearly with time for at least 10 min at 37 C. Exposure of cultures to TGF beta 1 stimulated initial rates of saturable Na(+)-dependent ascorbate transport, but did not affect nonspecific uptake or binding of the vitamin. Cells pretreated for 24 h with either vehicle or TGF beta 1 (3 ng/ml) and then assayed for transport of L-[14C] ascorbate (10 microM) showed significantly different transport activities (vehicle, 30 +/- 2; TGF beta 1, 44 +/- 3 nmol ascorbate/g protein/min; n = 14; P less than 0.005). Kinetic studies revealed that TGF beta 1 increased the maximum velocity of ascorbate transport without changing the affinity of the transporter for the vitamin, since the apparent maximum velocity increased from 83 to 106 nmol ascorbate/g protein/min; while the apparent Km remained unchanged at 20 microM L-ascorbate. The effect of this growth factor on ascorbate transport appeared to require protein synthesis, because it was completely blocked by cycloheximide. These results are consistent with TGF beta 1 increasing the rate of synthesis of either new Na+ ascorbate cotransporters or a regulatory protein that interacts with existing transporters to increase their turnover number. Enhanced uptake of ascorbate may contribute to the increase in collagen synthesis induced by TGF beta.     

Transforming growth factor-beta induces contraction of activated hepatic stellate cells

BACKGROUND/AIMS: Transforming growth factor-beta (TGF-beta) is a cytokine produced in abundance during liver injury. Recognizing the prominent roles that hepatic stellate cells (HSCs) and TGF-beta play in portal hypertension and fibrogenesis, respectively, we sought to evaluate the effect of TGF-beta on the contractility of activated HSCs. METHODS: Spontaneous immortalized cell lines of HSC origin were used in this study. Cells were grown in three-dimensional collagen gel lattice, transferred to 60 mm dishes and exposed to varying concentrations of TGF-beta1 in serum-free medium at 37 degrees C for up to 120 h. The area of the floating gels was measured using a Fluor S-MultiImager (Biorad), the cellular smooth muscle-alpha actin (SMA) content quantified and PKC activation studies conducted. RESULTS: TGF-beta1 induced a time- and dose-dependent decrease in lattice area up to 40% of control (P<0.05) that reflects the contraction of activated HSCs. This induced contraction was associated with increases in SMA content (3-fold, P<0.05) and PKC activation (5-fold, P<0.05) in these cells. Furthermore, pre-incubating with a PKC--specific inhibitor completely abrogated the TGF-beta-induced contraction. CONCLUSIONS: TGF-beta induces contraction of activated HSCs via an increase in SMA content and a PKC--mediated pathway.     

Transforming growth factor-beta1: differential effects on multiple myeloma versus normal B cells

Interleukin-6 (IL-6), a product of bone marrow stromal cells (BMSCs), is a growth factor for multiple myeloma (MM) cells. Transforming growth factor-beta1 (TGF-beta1) is also produced by BMSCs and can regulate IL- 6 secretion by several tissues, including BMSCs. The present study was designed to characterize in vitro tumor growth regulation by TGF-beta1 in MM. Sorted CD38+CD45RA- MM cells secreted significantly more TGF- beta1 (8.2 +/- 2.0 ng/mL) than peripheral blood mononuclear cells (P < .001), splenic B cells (P < .001), and CD40 ligand (CD40L) pretreated B cells (P < .05). TGF-beta1 secretion by MM-BMMCs (3.8 +/- 0.9 ng/mL) was significantly greater than by N-BMMCs (1.2 +/- 0.1 ng/mL, P < .001). MM-BMSCs also secreted significantly more TGF-beta1 (6.6 +/- 2.5 ng/mL, n = 11) than N-BMSCs (4.4 +/- 0.6 ng/mL, P < .02, n = 10) and N- BMSC lines (3.9 +/- 0.2 ng/mL, P < .02, n = 6). TGF-beta1 secretion was correlated with IL-6 secretion in MM-BMSCs. Anti-TGF-beta1 monoclonal antibody both blocked IL-6 secretion by BMSCs and inhibited the increments in IL-6 secretion by BMSCs induced by MM cell adhesion. Moreover, exogenous TGF-beta1 upregulated IL-6 secretion by MM-BMSCs, normal BMSCs, and CD38+ CD45RA- MM cells, as well as tumor cell proliferation. This is in contrast to the inhibitory effect of TGF- beta1 on proliferation and Ig secretion of normal splenic B cells. Finally, retinoblastoma proteins (pRB) are constitutively phosphorylated in MM cells; TGF-beta1 either did not alter or increased pRB phosphorylation. pRB are dephosphorylated in splenic B cells and phosphorylated in CD40L triggered B cells in contrast to its effects on MM cells, TGF-beta1 decreased phosphorylation of pRB in CD40L treated B cells. These results suggest that TGF-beta1 is produced in MM by both tumor cells and BMSCs, with related tumore cell growth. Moreover, MM cell growth may be enhanced by resistance of tumor cells to the inhibitory effects of TGF-beta1 on normal B-cell proliferation and Ig secretion.     

转化生长因子-β与高氧肺损伤

高氧肺损伤以早期肺泡炎和后期肺纤维化为特征。转化生长因子-β是一种多功能的细胞因子,控制着细胞功能的多个方面,包括细胞的增殖、分化,组织修复和细胞外基质蓄积的调控,免疫和炎症反应的调节。     

Transforming growth factor-beta 1 and interleukin-1 beta stimulate LDL receptor activity in Hep G2 cells.

The effect of transforming growth factor-beta 1 (TGF-beta 1) and interleukin-1 beta (IL-1 beta) on LDL receptor in Hep G2 cells was investigated. A greater than two-fold stimulation of the binding and internalisation of [125I]-labelled LDL at 37 degrees C was observed after an 18-h incubation of the cells with TGF-beta 1 at 50 ng/ml and IL-1 beta at 11,700 units/ml compared with control cells. Scatchard analysis of the binding of [125I]-labelled LDL at 4 degrees C after an 18-h incubation of the cells with 1170 units/ml IL-1 beta and 5 ng/ml TGF-beta 1 showed that they were both acting primarily by increasing LDL receptor number. The increase in LDL receptor activity could not be attributed to an increase in cell proliferation as TGF-beta 1 at concentrations from 0.05 ng/ml to 50 ng/ml had no significant effect on either cell number or [3H]thymidine incorporation into DNA whilst IL-1 beta inhibited DNA synthesis by more than 80% at a concentration of 11,700 units/ml but had significant effect on cell number. Cholesterol biosynthesis from [14C]acetate, in contrast to the stimulation of LDL receptor activity, was inhibited by approximately two-fold by incubation with TGF-beta 1 at 50 ng/ml and IL-1 beta at 11,700 units/ml.     

Transforming growth factor-beta and its role in asthma

Transforming growth factor-beta (TGF-beta) is an important fibrogenic and immunomodulatory factor that may play a role in the structural changes observed in the asthmatic airways. In vitro as well as in vivo studies have evidenced a dual role for TGF-beta: it can either function as a pro- or anti-inflammatory cytokine on inflammatory cells, participating into the initiation and resultion of inflammatory and immune responses in the airways. TGF-beta is also involved in the remodelling of the airway wall, and has in particular been related to the subepithelial fibrosis. TGF-beta is produced in the airways by inflammatory cells infiltrated in the bronchial mucosa, as well as by structural cells of the airway wall including fibroblasts, epithelial, endothelial and smooth muscle cells. By releasing TGF-beta, these different cell types may then participate into the increased levels of TGF-beta observed in bronchoalveolar lavage fluid from asthmatic patients. Taken together, these results suggest that TGF-beta may play a role in inflammation in asthma. However, as its role is dual in the modulation of inflammation, further studies are needed to elucidate the precise role of TGF-beta in the airways.     

Transforming growth factor-beta signaling and ubiquitinators in cancer

Transforming growth factor-beta (TGF-beta) represents a large family of growth and differentiation factors that mobilize complex signaling networks to regulate cellular differentiation, proliferation, motility, adhesion, and apoptosis. TGF-beta signaling is tightly regulated by multiple complex mechanisms, and its deregulation plays a key role in the progression of many forms of cancer. Upon ligand binding, TGF-beta signals are transduced by Smad proteins, which in turn are tightly dependent on modulation by adaptor proteins such as embryonic liver fodrin, Smad anchor for receptor activation, filamin, and crkl. A further layer of regulation is imposed by ubiquitin-mediated targeting and proteasomal degradation of specific components of the TGF-beta signaling pathway. This review focuses on the ubiquitinators that regulate TGF-beta signaling and the association of these ubiquitin ligases with various forms of cancer. Delineating the role of ubiquitinators in the TGF-beta signaling pathway could yield powerful novel therapeutic targets for designing new cancer treatments.     

Transforming growth factor-beta 1 and extracellular matrix-associated fibronectin expression in pulmonary lymphangioleiomyomatosis

STUDY OBJECTIVES: Lymphangioleiomyomatosis (LAM) is a rare disorder of unknown etiology, affecting almost exclusively women of childbearing age, that is associated with the proliferation of spindle cells and cystic changes in the affected lung. The underlying processes that contribute to this disease are poorly understood. Transforming growth factor (TGF)-beta(1) is a potent cytokine that promotes mesenchymal cell proliferation and regulates the synthesis of extracellular matrix (ECM) components, particularly fibronectins. Herein, we evaluate the expression of TGF beta(1) and matrix-associated fibronectin in lung specimens demonstrating LAM. DESIGN: Lung biopsy specimens that were confirmed to contain pathologic LAM cells were obtained from 13 patients. The specimens were submitted to immunohistochemical evaluation for TGF beta(1) and fibronectin, as well as the typical markers of LAM cells. Healthy lung parenchyma surrounding resected neoplasms was studied in a parallel fashion as control tissues. MEASUREMENTS AND RESULTS: In all 13 LAM cases and in healthy lung parenchyma, we demonstrated that TGF beta(1) localized consistently to airway epithelial cells. However, in LAM tissues, matrix-associated TGF beta(1) was also consistently found in regions containing pathologic LAM cells. Notably, more abundant TGF beta(1) was observed in highly cellular areas compared to the walls of chronic cystic regions in LAM tissues. Fibronectin, a matrix component that is strongly expressed in response to active TGF beta(1) was found to consistently colocalize with this protein in these highly cellular regions, supporting TGF beta(1) activity in these regions. The markers of proliferating LAM cells, including proliferating cell nuclear antigen, were also markedly present in these highly cellular LAM regions. CONCLUSION: These studies suggest that the proliferation of aberrant LAM cells may be associated with altered regional expression of TGF beta(1) and related ECM proteins.