The aim of this study was to examine the hypothesis that alveolar macrophages represent a significant source of matrix-degrading proteinases in the emphysematous lung. Macrophages from bronchoalveolar lavage fluid of 10 patients with emphysema and 10 normal volunteers were maintained in vitro for 24 h and assessed semiquantitatively for mRNA transcript levels of the matrix metalloproteinases (MMPs) gelatinases A and B, macrophage metalloelastase (MME), and interstitial collagenase. Release of these MMPs into the culture medium and secretion of neutrophil elastaselike activity was also assessed. Elevated levels of mRNA transcripts for gelatinase B (p < 0.0005) and interstitial collagenase (p < 0.0005) were observed in macrophages from emphysematous patients. Increased collagenase (p < 0.01) and neutrophil elastaselike activities (p < 0.001) were also measured in conditioned medium from patient macrophages. With gelatinase B, complexed forms of the enzyme were secreted by patient but not by control macrophages. No difference in transcript levels of gelatinase A or MME was observed between patient and control samples, and neither enzyme was detected in macrophage-conditioned media from either group. These results directly demonstrate that alveolar macrophages from the emphysematous lung produce elevated quantities of matrix-degrading enzymes with both elastolytic and collagenolytic activities.

Evidence-based recommendations for the diagnosis and treatment of patients with LAM are provided. Frequent reassessment and updating will be needed.

Rationale: Pulmonary lymphangioleiomyomatosis is a progressive cystic lung disease that is associated with infiltration of atypical smooth muscle-like cells. Previous descriptions of clinical characteristics of subjects with lymphangioleiomyomatosis have been based on a limited number of patients. Objectives: To describe the clinical characteristics of subjects with pulmonary lymphangioleiomyomatosis, both sporadic and tuberous sclerosis-related forms. Methods: Over a 3-yr period, from 1998 to 2001, 243 subjects with pulmonary lymphangioleiomyomatosis were enrolled into a national registry; 13 subjects who had already undergone lung transplantation were excluded for the purposes of this report. Measurements and Main Results: All 230 subjects were women, aged 18 to 76 yr (mean Ϯ SE, 44.5 Ϯ 0.65 yr). The average age at onset of symptoms was 38.9 Ϯ 0.73 yr and at diagnosis was 41.0 Ϯ 0.65 yr. Tuberous sclerosis complex was present in 14.8% of subjects. Pulmonary manifestations, most commonly spontaneous pneumothorax, were the primary events leading to the diagnosis in 86.5% of cases. Nearly 55% of the subjects were being treated with a progesterone derivative. An obstructive pattern on pulmonary function testing was observed in 57.3% of the subjects, whereas 33.9% had normal spirometric results. Women with tuberous sclerosis-related lymphangioleiomyomatosis were younger and had less impaired lung function compared with those with the sporadic form. Conclusions: The age range of women afflicted with pulmonary lymphangioleiomyomatosis is broader than previously appreciated and the degree of pulmonary function can be quite variable, with one-third of subjects having normal spirometry at enrollment into this registry.

Pulmonary emphysema is a condition of the lung characterised by progressive destruction Background -Matrix degradation in emand loss of functioning alveoli. The mechphysema has long been attributed to the anisms involved in extracellular matrix (ECM) action of neutrophil elastase (NE). More damage are not precisely known but a sigrecently a role for other proteases, parnificant body of evidence supports the proteaseticularly the matrix metalloproteinases antiprotease theory which postulates that an (MMPs), in the pathogenesis of this disexcess of proteolytic activity over the inhibitory ease has been proposed. To date, however, capacity of the lung leads to parenchymal dethe presence of MMPs in the lungs of struction. 1 Most studies to date have focused patients with emphysema has not been on the role of neutrophil elastase (NE) as the demonstrated.major effector protease involved. 2 More reMethods -Samples of bronchoalveolar cently, however, there has been considerable lavage (BAL) fluid from 10 patients with speculation on the potential involvement of emphysema and from control subjects other proteases, particularly the matrix metallomatched for sex and current smoking proteinases (MMPs), in matrix degradation in status were assessed for collagenase, emphysema.3 gelatinase, and NE activity. PulmonaryThe MMPs are a highly homologous family function tests and computed tomographic of endopeptidases which are collectively cap-(CT) scans were carried out on all study able of breaking down all the constituents of subjects.the alveolar ECM, including collagen, elastin, Results -Collagenase activity was detected proteoglycans, laminin, and fibronectin.4 They in BAL fluid samples from all em-are produced by a range of stromal cells and physematous patients but in only one by two of the major inflammatory cells imsmoking control (p<0.001). Gelatinase B plicated in emphysema -the alveolar macrowas present in six patients and in two phage and the neutrophil. Indirect evidence smoking controls (p<0.03). The con-that MMPs may play a part in tissue destruction comitant presence of gelatinase B in in emphysema comes from a number of studies. complex with lipocalin (NGAL) in the gel-Janoff et al demonstrated that the elastolytic atinase positive samples suggests that the activity of bronchoalveolar lavage (BAL) fluid neutrophil is a significant source of the from smokers was significantly inhibited by gelatinase B observed. NE was detected in metal chelating agents and concluded that

Our previous studies have shown that, through an active transport process, serotonin (5-HT) rapidly elevates[Formula: see text] formation, stimulates protein phosphorylation, and enhances proliferation of bovine pulmonary artery smooth muscle cells (SMCs). We presently show that 1 μM 5-HT also rapidly elevates phosphorylation and activation of the mitogen-activated protein (MAP) kinases extracellular signal-regulated kinase (ERK) 1 and ERK2 of SMCs, and the enhanced phosphorylation is blocked by the antioxidants Tiron, N-acetyl-l-cysteine (NAC), and Ginkgo biloba extract. Inhibition of MAP kinase with PD-98059 failed to block enhanced[Formula: see text] formation by 5-HT. Chinese hamster lung fibroblasts (CCL-39 cells), which demonstrate both 5-HT transporter and receptor activity, showed a similar response to 5-HT (i.e., enhanced mitogenesis, [Formula: see text]formation, and ERK1 and ERK2 phosphorylation and activation). Unlike SMCs, they also responded to 5-HT receptor agonists. We conclude that downstream signaling of MAP kinase is a generalized cellular response to 5-HT that occurs secondary to[Formula: see text] formation and may be initiated by either the 5-HT transporter or receptor depending on the cell type.

Renal angiomyolipoma is a kidney tumor in the perivascular epithelioid (PEComa) family that is common in patients with Tuberous Sclerosis Complex (TSC) and Lymphangioleiomyomatosis (LAM) but occurs rarely sporadically. Though histologically benign, renal angiomyolipoma can cause life-threatening hemorrhage and kidney failure. Both angiomyolipoma and LAM have mutations in TSC2 or TSC1. However, the frequency and contribution of other somatic events in tumor development is unknown. We performed whole exome sequencing in 32 resected tumor samples (n = 30 angiomyolipoma, n = 2 LAM) from 15 subjects, including three with TSC. Two germline and 22 somatic inactivating mutations in TSC2 were identified, and one germline TSC1 mutation. Twenty of 32 (62%) samples showed copy neutral LOH (CN-LOH) in TSC2 or TSC1 with at least 8 different LOH regions, and 30 of 32 (94%) had biallelic loss of either TSC2 or TSC1. Whole exome sequencing identified a median of 4 somatic non-synonymous coding region mutations (other than in TSC2/TSC1), a mutation rate lower than nearly all other cancer types. Three genes with mutations were known cancer associated genes (BAP1, ARHGAP35 and SPEN), but they were mutated in a single sample each, and were missense variants with uncertain functional effects. Analysis of sixteen angiomyolipomas from a TSC subject showed both second hit point mutations and CN-LOH in TSC2, many of which were distinct, indicating that they were of independent clonal origin. However, three tumors had two shared mutations in addition to private somatic mutations, suggesting a branching evolutionary pattern of tumor development following initiating loss of TSC2. Our results indicate that TSC2 and less commonly TSC1 alterations are the primary essential driver event in angiomyolipoma/LAM, whereas other somatic mutations are rare and likely do not contribute to tumor development.

Transforming growth factor-beta (TGF-beta) is involved in multiple processes including cell growth and differentiation. In particular, TGF-beta has been implicated in the pathogenesis of fibrotic lung diseases. In this study, we examined regulation of the mitogen-activated protein kinase pathway by TGF-beta1 in primary human lung fibroblasts. TGF-beta1 treatment resulted in extracellular signal-regulated kinase (ERK) pathway activation in a delayed manner, with maximal activity at 16 h. ERK activation occurred concomitantly with the induction of activator protein-1 (AP-1) binding, a nuclear factor required for activation of multiple genes involved in fibrosis. AP-1 binding was dependent on ERK activation, since the MEK-1 (mitogen-activated protein kinase kinase) inhibitor PD98059 inhibited TGF-beta1-induced binding. Induction of the receptor tyrosine kinase-linked growth factor, basic fibroblast growth factor (bFGF) protein expression temporally paralleled the activation of ERK/AP-1. Induction of AP-1 by TGF-beta1-conditioned medium was observed at 2 h, similar to AP-1 induction in response to exogenous bFGF. Dependence of ERK/AP-1 activation on bFGF induction was demonstrated by inhibition of TGF-beta1-induced ERK/AP-1 activation when conditioned medium from TGF-beta1-treated cells was incubated with bFGF-neutralizing antibody. Together, these results demonstrate that TGF-beta1 regulates the autocrine induction of bFGF, resulting in activation of the ERK mitogen-activated protein kinase pathway and induction of AP-1 binding.

Constitutive activation of mammalian target of rapamycin complex 1 (mTORC1), a key kinase complex that regulates cell size and growth, is observed with inactivating mutations of either of the tuberous sclerosis complex (TSC) genes, Tsc1 and Tsc2. Tsc1 and Tsc2 are highly expressed in cardiovascular tissue but their functional role there is unknown. We generated a tissue-specific knock-out of Tsc1, using a conditional allele of Tsc1 and a cre recombinase allele regulated by the smooth muscle protein-22 (SM22) promoter (Tsc1c/cSM22cre+/-) to constitutively activate mTOR in cardiovascular tissue. Significant gene recombination (∼80%) occurred in the heart by embryonic day (E) 15, and reduction in Tsc1 expression with increased levels of phosphorylated S6 kinase (S6K) and S6 was observed, consistent with constitutive activation of mTORC1. Cardiac hypertrophy was evident by E15 with post-natal progression to heart weights of 142 ± 24 mg in Tsc1c/cSM22cre+/- mice versus 65 ± 14 mg in controls (P < 0.01). Median survival of Tsc1c/cSM22cre+/- mice was 24 days, with none surviving beyond 6 weeks. Pathologic and echocardiographic analysis revealed severe biventricular hypertrophy without evidence of fibrosis or myocyte disarray, and significant reduction in the left ventricular end-diastolic diameter (P < 0.001) and fractional index (P < 0.001). Inhibition of mTORC1 by rapamycin resulted in prolonged survival of Tsc1c/cSM22cre+/- mice, with regression of ventricular hypertrophy. These data support a critical role for the Tsc1/Tsc2-mTORC1-S6K axis in the normal development of cardiovascular tissue and also suggest possible therapeutic potential of rapamycin in cardiac disorders where pathologic mTORC1 activation occurs.