Biomedical subjects

V J Ferrans

Publications and source records attributed to V J Ferrans.

At least 37 records · Page 2Linked to original sources

PubMed2000

Specific functional interaction of human cytohesin-1 and ADP-ribosylation factor domain protein (ARD1).

Activation of ADP-ribosylation factors (ARFs) is mediated by guanine nucleotide-exchange proteins, which accelerate conversion of inactive ARF-GDP to active ARF-GTP. ARF domain protein (ARD1), a 64-kDa GTPase with a C-terminal ADP-ribosylation factor domain, is localized to lysosomes and the Golgi apparatus. When ARD1 was used as bait to screen a human liver cDNA library using the yeast two-hybrid system, a cDNA for cytohesin-1, a approximately 50-kDa protein with ARF guanine nucleotide-exchange protein activity, was isolated. In this system, ARD1-GDP interacted well with cytohesin-1 but very poorly with cytohesin-2. In agreement, cytohesin-1, but not cytohesin-2, markedly accelerated [(35)S]guanosine 5'-3-O-(thio)triphosphate binding to ARD1. The effector region of the ARF domain of ARD1 appeared to be critical for the specific interaction with cytohesin-1. Replacement of single amino acids in the Sec7 domains of cytohesin-1 and -2 showed that residue 30 is critical for specificity. In transfected COS-7 cells, overexpressed ARD1 and cytohesin-1 were partially colocalized, as determined by confocal fluorescence microscopy. It was concluded that cytohesin-1 is likely to be involved in ARD1 activation, consistent with a role for ARD1 in the regulation of vesicular trafficking.

Amino Acid Sequence↗

PubMed2000

Identification and localization of two brefeldin A-inhibited guanine nucleotide-exchange proteins for ADP-ribosylation factors in a macromolecular complex.

Two brefeldin A (BFA)-inhibited guanine nucleotide-exchange proteins for ADP-ribosylation factors, 200-kDa BIG1 and 190-kDa BIG2, were copurified from bovine brain cytosol associated with >670-kDa macromolecular complexes. When observed by immunofluorescence in HeLa S3 and HepG2 cells, endogenous BIG1 and coexpressed BIG2 were distributed in a punctate pattern throughout the cytosol, and also concentrated in the perinuclear region, where endogenous BIG1 and BIG2 each partially colocalized with Golgi-specific 58K protein and gamma-adaptin. On Western blot analysis, both BIG1 and BIG2 were clearly more abundant in the cytosol than in the microsomal fractions. After density gradient centrifugation of a microsomal fraction, BIG1 and BIG2 were recovered in the same fraction as beta-COP, a marker for Golgi membranes. When cytosol from HeLa S3 cells was subjected to gel filtration and fractions were analyzed by Western blotting, the largest percentages of both BIG1 and BIG2 were detected in fractions containing proteins with a molecular mass of >670 kDa. Western blotting using anti-peptide antibodies specific for BIG1 or BIG2 demonstrated that approximately 70% of BIG2 was immunoprecipitated along with 100% of BIG1 by the anti-BIG1 IgG, and approximately 75% of BIG1 was coprecipitated with 100% of BIG2 by the anti-BIG2 IgG. All observations were consistent with the conclusion that significant fractions of BIG1 and BIG2 exist as components of the same macromolecular complexes in bovine brain cytosol and are similarly localized in cultured cells.

ADP-Ribosylation Factors↗

PubMed2000

Similarities in function and gene structure of cytohesin-4 and cytohesin-1, guanine nucleotide-exchange proteins for ADP-ribosylation factors.

Activation of ADP-ribosylation factors (ARFs), approximately 20-kDa GTPases that are inactive in the GDP-bound form, depends on guanine nucleotide-exchange proteins (GEPs) to accelerate GTP binding. A novel ARF GEP, designated cytohesin-4, was cloned from a human brain cDNA library. Deduced amino acid sequence of the 47-kDa protein contains the same structural components present in cytohesin -1, -2, and -3, including an approximately 200-amino acid Sec7 domain with an approximately 100-residue pleckstrin homology domain near the C terminus. The Sec7 domain sequence is 77% identical to those of other cytohesins. Structures of the cytohesin-4 and cytohesin-1 genes were remarkably similar, except for an extra 3-base pair (GAG) exon present in cytohesin-1. Two mRNAs with and without the 3-base pair sequence were found in brain in different ratios for cytohesin-1, -2, and -3 but not cytohesin-4. Recombinant cytohesin-4 stimulated guanosine 5'-3-O-(thio)triphosphate binding by human ARF1 and ARF5 but not ARF6. Like other cytohesins and unlike the approximately 200-kDa ARF GEPs, it was not inhibited by brefeldin A. A cytohesin-4 mRNA of approximately 3.7 kilobases, abundant in leukocytes, was not detected in most tissues. Among separated populations of blood cells, approximately 90% of CD33(+) (monocytes), 80% of CD2(+) (NK/T), and 10-20% of CD19(+) (B) cells contained cytohesin-4 mRNA by in situ hybridization. Thus, in gene structure and brefeldin A-insensitive GEP activity, cytohesin-4 resembles other cytohesins, but its tissue distribution differs considerably, consistent with a different specific function.

ADP-Ribosylation Factors↗

PubMed2000

Nonmuscle myosin II localizes to the Z-lines and intercalated discs of cardiac muscle and to the Z-lines of skeletal muscle.

To understand the role of nonmuscle myosin II in cardiac and skeletal muscle, we used a number of polyclonal antibodies, three detecting nonmuscle myosin heavy chain II-B (NMHC II-B) and two detecting NMHC II-A, to examine the localization of these two proteins in fresh-frozen, acetone-fixed sections of normal human and mouse hearts and human skeletal muscles. Results were similar in both species and were confirmed by examination of fresh-frozen sections of human hearts subjected to no fixation or to treatment with either 4% p-formaldehyde or 50% glycerol. NMHC II-B was diffusely distributed in the cytoplasm of cardiac myocytes during development, but after birth it was localized to the Z-lines and intercalated discs. Dual labeling showed almost complete colocalization of NMHC II-B with alpha-actinin. Whereas endothelial cells, smooth muscle cells and fibroblasts showed strong immunoreactivity for NMHC II-A and NMHC II-B, cardiac myocytes only showed reactivity for the latter. The Z-lines of human skeletal muscle cells, in contrast to those of cardiac myocytes, gave positive reactions for both NMHC II-A and NMHC II-B. The presence of a motor protein in the Z-lines and intercalated discs raises the possibility that these structures may play a more dynamic role in the contraction/relaxation mechanism of cardiac and skeletal muscle than has been previously suspected.

Actinin↗

PubMed2000

Comparison of the protective effects of amifostine and dexrazoxane against the toxicity of doxorubicin in spontaneously hypertensive rats.

PURPOSE: To compare the protective effects of amifostine and dexrazoxane against the chronic toxicity induced by doxorubicin in spontaneously hypertensive rats (SHR). METHODS: The animals were pretreated with amifostine (200 mg/kg. i.p.), dexrazoxane (25 mg/kg, i.p.) or saline 30 min before the administration of doxorubicin (1 mg/kg, i.v.), once-weekly for 12 weeks. Control animals received similar amounts of amifostine or saline. The SHR underwent necropsy examination 1 week after the last dosing, and cardiac, renal, and gastrointestinal lesions were graded semiquantitatively. RESULTS: Amifostine and dexrazoxane provided equal degrees of protection against the renal toxicity of doxorubicin. However, dexrazoxane was more cardioprotective than amifostine, and prevented the mortality induced by doxorubicin. This mortality was not decreased by pretreatment with amifostine. The loss of body weight caused by doxorubicin was actually worsened by coadministration of amifostine. CONCLUSIONS: Compared to dexrazoxane, amifostine provided a comparable degree of protection against the nephrotoxicity of doxorubicin, but was less cardioprotective and did not prevent the mortality and loss of body weight produced by doxorubicin. These differences may be related to the fact that amifostine may act as a scavenger of reactive oxygen species, whereas dexrazoxane may prevent their formation.

Amifostine↗

PubMed2000

Matrix metalloproteinases and tissue inhibitors of metalloproteinases in bronchial squamous preinvasive lesions.

Metalloproteinases and their inhibitors are known to play an important role in the extracellular matrix remodeling associated with preinvasive lesions and invasive carcinomas; however, little is known about their role in early lung carcinoma. Immunohistochemical studies were made of the reactivity of bronchial squamous preneoplastic lesions from cigarette smokers, including basal cell hyperplasia, squamous metaplasia, dysplasia, carcinoma in situ, and invasive squamous cell carcinoma for matrix metalloproteinases (MMPs), their tissue inhibitors (TIMPs), and type IV collagen in 13 patients. Staining for type IV collagen disclosed discontinuities in basement membranes from basal cell hyperplasia to dysplasia, progressing to destruction in carcinoma in situ and invasive carcinoma. Reactivity for MMP-9 was mild in basal cell hyperplasia and squamous metaplasia, increasing in carcinoma in situ and invasive carcinoma. In contrast, reactivity for MMP-1 was strong in basal cell hyperplasia and squamous metaplasia, decreasing in carcinoma in situ and invasive carcinoma. Some neoplastic cells in carcinoma in situ and invasive carcinoma were MMP-3 positive. Staining for MMP-2 and TIMP-1 was moderate to strong in all squamous preinvasive lesions. Confocal microscopy showed MMP-9-positive cells passing through fragmented basement membranes in which type IV collagen and MMP-9 were colocalized. Type IV collagen colocalized with MMP-2 in all lesions and with TIMP-1 in basal cell hyperplasia and squamous metaplasia. The inverse relationships between the reactivity for MMP-1 and MMP-9 with progression of bronchial squamous preinvasive lesions suggest important roles for these MMPs in basement membrane remodeling in these lesions.

Aged↗

PubMed2000

Sporadic cardiac and skeletal myopathy caused by a de novo desmin mutation.

Desmin myopathy is a familial or sporadic disorder characterized by intracytoplasmic accumulation of desmin in the muscle cells. We and others have previously identified desmin gene mutations in patients with familial myopathy, but close to 45% of the patients do not report previous family history of the disease. The present study was conducted to determine the cause of desmin myopathy in a sporadic patient presenting with symmetrical muscle weakness and atrophy combined with atrioventricular conduction block requiring a permanent pacemaker. A novel heterozygous R406W mutation in the desmin gene was identified by sequencing cDNA and genomic DNA. Expression of a construct containing the patient's mutant desmin cDNA in SW13 (vim-) cells demonstrated a high pathogenic potential of the R406W mutation. This mutation was not found in the patient's father, mother or sister by sequencing and restriction analysis. Testing with five microsatellite markers and four intragenic single nucleotide polymorphisms excluded alternative paternity. Haplotype analysis indicates that the patient's father was germ-line mosaic for the desmin mutation. We conclude that de novo mutations in the desmin gene may be the cause of sporadic forms of desmin-related cardiac and skeletal myopathy.

Adult↗

PubMed2000

Modulation of retinoid signalling through NGF-induced nuclear export of NGFI-B.

The retinoid-X receptor (RXR) regulates multiple hormonal pathways through heterodimerization with nuclear receptors such as the all-trans retinoic acid receptor (RAR). The orphan nuclear receptor NGFI-B (also called Nur77) can heterodimerize with RXR. Here we show that nerve growth factor (NGF) induces the phosphorylation of Ser 105 of NGFI-B in PC12 phaeochromocytoma cells, resulting in translocation of the NGFI-B-RXR heterodimer complex out of the nucleus using nuclear export signals within NGFI-B. As a consequence of the redistribution of RXR, the transcriptional activity of RXR-RAR is reduced. NGFI-B-mediated nuclear export of receptors may serve as a mechanism for crosstalk between NGF and retinoid pathways.

Amino Acid Sequence↗

PubMed2000

Extrapulmonary lymphangioleiomyomatosis (LAM): clinicopathologic features in 22 cases.

We describe the lesions of extrapulmonary lymphangioleiomyomatosis (LAM) affecting the lymph nodes of the mediastinum and retroperitoneum in 22 women (mean age +/- SD, 42.4+/-10.5 years). In most of these patients, the diagnosis of extrapulmonary LAM preceded that of pulmonary LAM, usually by 1 to 2 years. Eleven patients had distinct symptoms, including chylous pleural effusion and/or ascites, abdominal pain, and palpable abdominal masses. In the other 11 patients, the masses caused no symptoms. Well-circumscribed, encapsulated masses, measuring up to 20 cm in size, occurred in the mediastinum in 2 patients, the upper retroperitoneum in 15, extensive areas of the retroperitoneum in 2, and the pelvis in 3. The masses exceeding 3 cm in diameter contained large, multiple cysts filled with yellow-tan chylous fluid. Histologically, the masses were characterized by a proliferation of smooth muscle cells (LAM cells) arranged in fascicular, trabecular, and papillary patterns, which were associated with slit-like vascular channels. The LAM cells varied from small, spindle-shaped cells to large epithelioid cells. Immunohistochemical studies showed a strong reactivity of most LAM cells for alpha-smooth muscle actin and smooth muscle myosin heavy chain and a weak to moderate reactivity of a lesser number of cells for desmin and nonmuscle myosin heavy chain II-B. A reaction for HMB-45 and estrogen and progesterone receptors was observed mainly in epithelioid LAM cells. These patterns of reactivity are similar to those observed in pulmonary LAM. However, the chylous cysts are not a feature of pulmonary LAM and are thought to result from obstruction of lymphatics.

Actins↗

PubMed2000

Idiopathic nonspecific interstitial pneumonia: prognostic significance of cellular and fibrosing patterns: survival comparison with usual interstitial pneumonia and desquamative interstitial pneumonia.

Nonspecific interstitial pneumonia (NSIP) has been proposed as a histologic subtype of idiopathic interstitial pneumonia with lung biopsy findings that are inconsistent with those of other idiopathic interstitial pneumonias. NSIP has a broad spectrum of histologic findings and a variable prognosis. The aim of this study was to determine whether it would be preferable to subdivide NSIP into cellular and fibrosing patterns. The authors classified lung biopsies from 101 patients with idiopathic interstitial lung disease as having histologic patterns of desquamative interstitial pneumonia (DIP), usual interstitial pneumonia (UIP), or cellular or fibrosing NSIP. Survival analysis was performed using the Kaplan-Meier method. Due to histologic, clinical, and survival similarities, the patients with idiopathic NSIP with lung biopsies that showed fibrosing as well as fibrosing and cellular patterns were combined into a single group of NSIP, fibrosing pattern. Of the 101 patients, 16 patients (9 women, 7 men) had idiopathic DIP; 56 patients (17 women, 39 men) had idiopathic UIP; 22 patients (7 women, 15 men) had idiopathic NSIP, fibrosing pattern; and 7 patients (2 women, 5 men) had idiopathic NSIP, cellular pattern. The patients had a mean age of 42, 51, 50, and 39 years respectively. Patients with idiopathic NSIP, cellular pattern had a better 5- and 10-year survival than those with idiopathic NSIP, fibrosing pattern (100% vs 90% and 100% vs 35% respectively, p = 0.027). Survival of patients with idiopathic UIP was worse than that of patients with idiopathic NSIP, fibrosing pattern (p = 0.014). The difference, however, was more evident at 5 years (43% vs 90%) than at 10 years (15% vs 35%). The 5- and 10-year survival of patients with idiopathic NSIP, cellular pattern and DIP was 100%, which was significantly better than that of patients with idiopathic UIP (p <0.0001). Based on these data, NSIP should be separated into cellular and fibrosing patterns, because these histologic patterns are associated with different clinical characteristics and prognoses.

Adult↗

PubMed2000

Role for mitochondrial oxidants as regulators of cellular metabolism.

Leakage of mitochondrial oxidants contributes to a variety of harmful conditions ranging from neurodegenerative diseases to cellular senescence. We describe here, however, a physiological and heretofore unrecognized role for mitochondrial oxidant release. Mitochondrial metabolism of pyruvate is demonstrated to activate the c-Jun N-terminal kinase (JNK). This metabolite-induced rise in cytosolic JNK1 activity is shown to be triggered by increased release of mitochondrial H(2)O(2). We further demonstrate that in turn, the redox-dependent activation of JNK1 feeds back and inhibits the activity of the metabolic enzymes glycogen synthase kinase 3beta and glycogen synthase. As such, these results demonstrate a novel metabolic regulatory pathway activated by mitochondrial oxidants. In addition, they suggest that although chronic oxidant production may have deleterious effects, mitochondrial oxidants can also function acutely as signaling molecules to provide communication between the mitochondria and the cytosol.

3T3 Cells↗

PubMed2000

Identification of lysosomal and Golgi localization signals in GAP and ARF domains of ARF domain protein 1.

ADP ribosylation factors (ARFs) are approximately 20-kDa guanine nucleotide-binding proteins that activate cholera toxin and phospholipase D and are critical components of vesicular trafficking pathways. ARF domain protein 1 (ARD1), a member of the ARF superfamily, contains a 46-kDa amino-terminal extension, which acts as a GTPase-activating protein (GAP) with activity towards its ARF domain. When overexpressed, ARD1 was associated with lysosomes and the Golgi apparatus. In agreement with this finding, lysosomal and Golgi membranes isolated from human liver by immunoaffinity contained native ARD1. ARD1, expressed as a green fluorescent fusion protein, was initially associated with the Golgi network and subsequently appeared on lysosomes, suggesting that ARD1 might undergo vectorial transport between the two organelles. Here we show by microscopic colocalization that GAP and ARF domains determine lysosomal and Golgi localization, respectively, consistent with the presence of more than one signal motif. Using truncated ARD1 molecules, expressed as green fluorescent fusion proteins, it was found that the signal for lysosomal localization was present in residues 301 to 402 of the GAP domain. Site-specific mutagenesis demonstrated that the sequence (369)KXXXQ(373) in the GAP domain was responsible for lysosomal localization. Association of ARD1 with the Golgi apparatus required tyrosine-based motifs. A green fluorescent fusion protein containing the QKQQQQF motif was partially associated with lysosomes, suggesting that this motif contains the information sufficient for lysosomal targeting. These results suggest that ARD1 is a multidomain protein with ARF and GAP regions, which contain Golgi and lysosomal localization signals, respectively, that could function in vesicular trafficking.

3T3 Cells↗

PubMed2000

Desmin splice variants causing cardiac and skeletal myopathy.

Desmin myopathy is a hereditary or sporadic cardiac and skeletal myopathy characterised by intracytoplasmic accumulation of desmin reactive deposits in muscle cells. We have characterised novel splice site mutations in the gene desmin resulting in deletion of the entire exon 3 during the pre-mRNA splicing. Sequencing of cDNA and genomic DNA identified a heterozygous de novo A to G change at the +3 position of the splice donor site of intron 3 (IVS3+3A-->G) in a patient with sporadic skeletal and cardiac myopathy. A G to A transition at the highly conserved -1 nucleotide position of intron 2 affecting the splice acceptor site (IVS2-1G-->A) was found in an unrelated patient with a similar phenotype. Expression of genomic DNA fragments carrying the IVS3+3A-->G and IVS2-1G-->A mutations confirmed that these mutations cause exon 3 deletion. Aberrant splicing leads to an in frame deletion of 32 complete codons and is predicted to result in mutant desmin lacking 32 amino acids from the 1B segment of the alpha helical rod. Functional analysis of the mutant desmin in SW13 (vim-) cells showed aggregation of abnormal coarse clumps of desmin positive material dispersed throughout the cytoplasm. This is the first report on the pathogenic potentials of splice site mutations in the desmin gene.

Adult↗

PubMed2000

Downregulation of estrogen and progesterone receptors in the abnormal smooth muscle cells in pulmonary lymphangioleiomyomatosis following therapy. An immunohistochemical study.

Immunohistochemical and confocal microscopic studies were made on lung tissue from 10 women with lymphangioleiomyomatosis (LAM) to evaluate the distribution of estrogen receptors (ER) and progesterone receptors (PR) in the abnormal smooth muscle cells (LAM cells) that characterize this disorder. PR and ER were localized mainly in the nuclei of large, epithelioid LAM cells, in five patients in whom tissues were obtained before treatment. However, the reaction for PR and ER was essentially negative in similarly processed tissues from five patients studied after receiving hormonal therapy (progesterone and tamoxifen). In the untreated group, staining for ER and PR colocalized with that for HMB-45, but not with that for membrane type-1 matrix metalloproteinase (MT-1-MMP), which we have shown to be localized in proliferating LAM cells. These observations demonstrate that PR and ER are selectively expressed in a subpopulation of LAM cells that are larger in size, have a limited ability to proliferate, and do not produce MT-1-MMP, the enzyme that activates MMP-2 (which is secreted by LAM cells and is capable of lysing elastin and collagens). ER and PR in LAM cells appear to be downregulated by hormonal therapy.

Adult↗

PubMed2000

Gene dosage affects the cardiac and brain phenotype in nonmuscle myosin II-B-depleted mice.

Complete ablation of nonmuscle myosin heavy chain II-B (NMHC-B) in mice resulted in cardiac and brain defects that were lethal during embryonic development or on the day of birth. In this paper, we report on the generation of mice with decreased amounts of NMHC-B. First, we generated B(DeltaI)/B(DeltaI) mice by replacing a neural-specific alternative exon with the PGK-Neo cassette. This resulted in decreased amounts of NMHC-B in all tissues, including a decrease of 88% in the heart and 65% in the brain compared with B(+)/B(+) tissues. B(DeltaI)/B(DeltaI) mice developed cardiac myocyte hypertrophy between 7 months and 11 months of age, at which time they reexpressed the cardiac beta-MHC. Serial sections of B(DeltaI)/B(DeltaI) brains showed abnormalities in neural cell migration and adhesion in the ventricular wall. Crossing B(DeltaI)/B(DeltaI) with B(+)/B(-) mice generated B(DeltaI)/B(-) mice, which showed a further decrease of approximately 55% in NMHC-B in the heart and brain compared with B(DeltaI)/B(DeltaI) mice. Five of 8 B(DeltaI)/B(-) mice were born with a membranous ventricular septal defect. Moreover, 5 of 5 B(DeltaI)/B(-) mice developed myocyte hypertrophy by 1 month; B(DeltaI)/B(-) mice also reexpressed the cardiac beta-MHC. More than 60% of B(DeltaI)/B(-) mice developed overt hydrocephalus and showed more severe defects in neural cell migration and adhesion than did B(DeltaI)/B(DeltaI) mice. These data on B(DeltaI)/B(DeltaI) and B(DeltaI)/B(-) mice demonstrate a gene dosage effect of the amount of NMHC-B on the severity and time of onset of the defects in the heart and brain.

Animals↗

PubMed2000

Heterogeneous distribution of thrombomodulin and von Willebrand factor in endothelial cells in the human pulmonary microvessels.

Laser scanning confocal fluorescence microscopy techniques were used to study the localization of von Willebrand factor (vWf; Factor VIII-related antigen) and thrombomodulin (transmembrane receptor for thrombin) in the microvascular endothelial cells in the normal human lung. Tissues were obtained from lobectomy specimens resected for solitary nodules (7 adenocarcinomas and 4 hamartomas) from 11 patients. The plasma membranes of the capillary endothelial cells in the alveolar zones (A-zones) showed red linear fluorescence for thrombomodulin. However, their cytoplasm was mostly unreactive for vWf. The microvessels which were located in the connective tissue (C-zones), including peribronchial, and subpleural areas and large vascular walls, consistently demonstrated band-like green fluorescence for vWf in their cytoplasm, and their plasma membranes usually lacked reactivity for thrombomodulin. Only a limited number of peribronchial capillaries measuring <10 microm in diameter showed a mosaic-like appearance, in which red fluorescence along the plasma membranes was found together with green fluorescence in the subjacent cytoplasm. In the juxtaalveolar (J-zones) microvessels located along the borders between A- and C-zones, and measuring up to 40 microm in diameter, the endothelial cells showed a mosaic-like pattern of distribution of the two antigens. However, the localization of thrombomodulin in the J-zone microvessels was separate and independent from that of vWf. The thrombomodulin-reactive cells were directly connected to the alveolar capillary endothelial cells. Heterogeneous patterns of distribution of thrombomodulin and vWf suggest that topographic differences of endothelial function occur to maintain a balance of coagulation and anticoagulation in the normal human lung.

Adult↗

PubMed2000

Lymphangioleiomyomatosis (LAM): a review of clinical and morphological features.

A review is presented of the clinical and morphological manifestations of lymphangioleiomyomatosis (LAM), a systemic disorder of unknown etiology that affects women. The clinical features include dyspnea, hemoptysis, recurrent pneumothorax, chylothorax, and chylous ascites. It is characterized by: 1) proliferation of abnormal smooth muscle cells (LAM cells) in pulmonary interstitium and along the axial lymphatics of the thorax and abdomen; 2) thin-walled pulmonary cysts, and 3) a high incidence of angiomyolipomas. The pulmonary cystic lesions have a characteristic appearance on high resolution computed tomography. The most specific method for diagnosing LAM is lung biopsy to demonstrate the presence of LAM cells, either by their characteristic histological appearance or by specific immunostaining with HMB-45 antibody. LAM cells differ in several important respects from the types of smooth muscle cells normally present in lung. Their reactivity with HMB-45 antibody is localized in stage I and stage II melanosomes. LAM cells show additional evidence of incomplete melanogenesis, and the significance of these observations remains to be determined. Two types of LAM cells are recognized: 1) small, spindle-shaped cells that are centrally located in the LAM nodules and are highly immunoreactive for matrix metalloproteinase-2 (MMP-2), its activating enzyme (MT-1-MMP), and proliferating cell nuclear antigen (PCNA), and 2) large, epithelioid cells that are distributed along the periphery of the nodules and show a high degree of immunoreactivity with HMB-45 antibody and with antibodies against estrogen and progesterone receptors. Types of treatment used for LAM include oophorectomy, administration of Lupron or progesterone and in very severe cases, pulmonary transplantation (following the onset of respiratory insufficiency, not relieved by O(2)).

Antibodies, Neoplasm↗

PubMed2000

Role for activation of matrix metalloproteinases in the pathogenesis of pulmonary lymphangioleiomyomatosis.

BACKGROUND: Matrix metalloproteinases (MMPs) have been shown to be involved in the pathogenesis of the destructive pulmonary lesions in patients with lymphangioleiomyomatosis (LAM); in the present report, the activation of these enzymes is examined. OBJECTIVE: To evaluate the role of MMPs and their activating enzymes, immunohistochemical and confocalmicroscopic techniques were used to localize alpha-smooth muscle actin (alpha-SMA), HMB-45, proliferating cell nuclear antigen (PCNA), MMP-2, membrane-type 1 MMP (MT1-MMP), MT2-MMP, and MT3-MMP in lung tissues from 10 women with LAM. Tissue samples were obtained from 5 patients before treatment and in 5 patients after hormone treatment (progesterone and/or tamoxifen citrate). RESULTS: Staining for alpha-SMA and MMP-2 was present in all the abnormal smooth muscle cells (LAM cells) in both groups. The percentages of PCNA-, MMP-2-, or MT1-MMP-positive LAM cells were much higher in the untreated group than in the treated group, whereas the percentages of HMB-45-reactive LAM cells were similar in both groups. The reactions for MT1-MMP and PCNA were preferentially localized in small spindle-shaped LAM cells; the reaction for HMB-45 was found in large epithelioid LAM cells. Many of the PCNA-positive cells were also positive for MT1-MMP. Staining for MT2-MMP and MT3-MMP was negative. CONCLUSIONS: This study demonstrates an association between cellular proliferation and the presence of MT1-MMP in LAM cells. The activation of MMP-2 by MT1-MMP may play an important role in the destruction of lung tissue in this disorder.

Actins↗