Isobavachalcone as an Active Membrane Perturbing Agent and Inhibitor of ABCB1 Multidrug Transporter.

Isobavachalcone (IBC) is an active substance from the medicinal plant Psoralea corylifolia. This prenylated chalcone was reported to possess antioxidative, anti-inflammatory, antibacterial, and anticancer activities. Multidrug resistance (MDR) associated with the over-expression of the transporters of vast substrate specificity such as ABCB1 (P-glycoprotein) belongs to the main causes of cancer chemotherapy failure. The cytotoxic, MDR reversing, and ABCB1-inhibiting potency of isobavachalcone was studied in two cellular models: human colorectal adenocarcinoma HT29 cell line and its resistant counterpart HT29/Dx in which doxorubicin resistance was induced by prolonged drug treatment, and the variant of MDCK cells transfected with the human gene encoding ABCB1. Because MDR modulators are frequently membrane-active substances, the interaction of isobavachalcone with model phosphatidylcholine bilayers was studied by means of differential scanning calorimetry. Molecular modeling was employed to characterize the process of membrane permeation by isobavachalcone. IBC interacted with ABCB1 transporter, being a substrate and/or competitive inhibitor of ABCB1. Moreover, IBC intercalated into model membranes, significantly affecting the parameters of their main phospholipid phase transition. It was concluded that isobavachalcone interfered both with the lipid phase of cellular membrane and with ABCB1 transporter, and for this reason, its activity in MDR cancer cells was presumptively beneficial.

Organosilicon Compounds, SILA-409 and SILA-421, as Doxorubicin Resistance-Reversing Agents in Human Colon Cancer Cells.

Multidrug resistance (MDR) that occurs in cancer cells constitutes one of the major reasons for chemotherapy failure. The main molecular mechanism of MDR is overexpression of protein transporters from the ATP-binding cassette (ABC) superfamily, such as ABCB1 (multidrug resistance protein 1 (MDR1), P-glycoprotein). At the expense of ATP hydrolysis, ABCB1 pumps a diverse range of substrates (including anticancer drugs) out of the cell, thereby reducing their intracellular concentration. In the present study, the ability of two patented disiloxanes (SILA-409 and SILA-421) to reverse drug resistance in human colon adenocarcinoma cell lines LoVo and LoVo/Dx was investigated. It was demonstrated that both compounds in concentrations of 0.5-1 µM strongly increased the sensitivity of LoVo/Dx cells to doxorubicin. By means of an accumulation test in which rhodamine 123 was used as an ABCB1 substrate analogue, both organosilicon compounds were also shown to inhibit ABCB1 transport activity. The intracellular accumulation of doxorubicin was also increased, and more drug entered the cellular nuclei of resistant cells in the presence of the studied compounds. In conclusion, both SILA-409 and SILA-421 were demonstrated to be effective MDR reversal agents in resistant human colon cancer cells.

Interaction of selected alkoxy naringenin oximes with model and bacterial membranes.

Naringenin is a flavonoid found in many fruits and herbs, most notably in grapefruits. In recent years, this compound and its derivatives have been of great interest due to their high biological activity, including fungicidal and bactericidal effects, also in relation to multidrug-resistant bacteria. Membrane interactions of naringenin oxime (NO) and its 7-O-alkyl (7-alkoxy) derivatives, such as methyl (7MENO), ethyl (7ETNO), isopropyl (7IPNO), n-butyl (7BUNO) and n-pentyl (7PENO) were studied. Thermotropic properties of model membranes were investigated via differential scanning calorimetry (DSC), the influence on lipid raft mimicking giant unilamellar vesicles (GUVs) via fluorescence microscopy, and membrane permeability via measuring calcein leakage from liposomes. Molecular calculations supplemented the study. The influence of naringenin oximes on two strains of multidrug resistant bacteria: Staphylococcus aureus KJ and Enterococcus faecalis 37VRE was also investigated. In DSC studies all compounds reduced the temperature and enthalpy of main phase transition and caused disappearing of the pretransition. NO was the least active. The reduction in the area of surface domains in GUVs was observed for NO. Compounds NO and 7BUNO resulted in very low secretion of calcein from liposomes (permeability < 3 %). The highest results were observed for 7MENO (88.4 %) and 7IPNO (78.5 %). When bacterial membrane permeability was investigated all compounds caused significant release of propidium iodide from S. aureus (31.6-87.0 % for concentration 128 µg/mL). In the case of E. faecalis, 7ETNO (75.7 %) and NO (28.8 %) were the most active. The rest of the tested compounds showed less activity (permeability < 13.9 %). The strong evidence was observed that antibacterial activity of the tested compounds may be associated with their interaction with bacterial membrane.

Methoxychalcones as potential anticancer agents for colon cancer: Is membrane perturbing potency relevant?

Chalcones are naturally produced by many plants, and constitute precursors for the synthesis of flavons and flavanons. They were shown to possess antibacterial, antifungal, anti-cancer, and anti- inflammatory properties. The goal of the study was to assess the suitability of three synthetic methoxychalcones as potential anticancer agents. In a panel of colon cancer cell lines they were demonstrated to be cytotoxic, proapoptotic, causing cell cycle arrest, and increasing intracellular level of reactive oxygen species. Anticancer activity of the compounds was not diminished in the presence of stool extract containing microbial enzymes that could change the structure of chalcones. Moreover, methoxychalcones interacted strongly with model phosphatidylcholine membranes as detected by differential scanning calorimetry. Metohoxychalcones particularly affected the properties of lipid domains in giant unilamellar liposomes formed from raft-mimicking lipid composition. This may be of importance since many molecular targets for therapy of metastatic colon cancer are raft-associated receptors (e.g., receptor tyrosine kinases). The importance of membrane perturbing potency of methoxychalcones for their biological activity was additionally corroborated by the results obtained by molecular modelling.

Modulators of cellular cholesterol homeostasis as antiproliferative and model membranes perturbing agents.

Cholesterol is an important component of mammalian cell membranes affecting their fluidity and permeability. Together with sphingomyelin, cholesterol forms microdomains, called lipid rafts. They play important role in signal transduction forming platforms for interaction of signal proteins. Altered levels of cholesterol are known to be strongly associated with the development of various pathologies (e.g., cancer, atherosclerosis and cardiovascular diseases). In the present work, the group of compounds that share the property of affecting cellular homeostasis of cholesterol was studied. It contained antipsychotic and antidepressant drugs, as well as the inhibitors of cholesterol biosynthesis, simvastatin, betulin, and its derivatives. All compounds were demonstrated to be cytotoxic to colon cancer cells but not to non-cancerous cells. Moreover, the most active compounds decreased the level of free cellular cholesterol. The interaction of drugs with raft-mimicking model membranes was visualized. All compounds reduced the size of lipid domains, however, only some affected their number and shape. Membrane interactions of betulin and its novel derivatives were characterized in detail. Molecular modeling indicated that high dipole moment and significant lipophilicity were characteristic for the most potent antiproliferative agents. The importance of membrane interactions of cholesterol homeostasis-affecting compounds, especially betulin derivatives, for their anticancer potency was suggested.

Dynamic similarity predicts gait parameters for Homo floresiensis and the Laetoli hominins.

Late in 2004, the skeletal remains of a pygmy-sized hominin recovered from a cave on the Indonesian island of Flores were first documented, with the authors concluding that the "postcranial anatomy [was] consistent with human-like obligate bipedalism" (Brown et al. [2004]: Nature 431:1055-1061). We have assumed that Homo floresiensis, who was estimated to be 18,000-years-old, walked with a gait pattern that was dynamically similar to modern man. The dynamic similarity hypothesis was also applied to the Australopithecines that left their footprints at Laetoli 4-million-years ago. According to this hypothesis, dimensionless gait parameters can be used in combination with known leg length or step length to calculate velocity of bipedal locomotion. We have gathered data on 20 extant modern humans to calculate the standard estimates of error when predicting gait parameters. We predict that the Homo floresiensis specimen walked at a velocity of 1.11 +/- 0.14 m/s. For the Laetoli footprints, the velocity for Track 1 was estimated to be 1.03 +/- 0.12 m/s and for Track 2 to be 1.14 +/- 0.12 m/s. These latter values for Australopithecines are greater than prior analyses, but are in good agreement with more recent work based on evolutionary robotics. Since modern man walks at 1.44 +/- 0.14 m/s, our results suggest that, despite their diminutive size, these ancient hominins were capable of ranging across a wide geographical area.

Non-invasive diagnostic and functional evaluation of cardiac involvement in patients with systemic sclerosis.

Elevated serum brain natriuretic peptide (BNP) released from myocytes of ventricles upon stretch have been found in patients with isolated right ventricular (RV) pressure overload. However, limited data suggest that serum BNP may be elevated in systemic sclerosis (SSc) patients, especially with RV dysfunction. We assessed serum N-terminal proBNP (NT-proBNP) in SSc and evaluated whether it reflects the severity of RV overload. We prospectively studied 51 consecutive patients (47F, mean age 53.3 +/- 15.2 years) with SSc (mean disease duration 9 +/- 12.4 years). The control group formed 31 healthy subjects (27F, mean age 52.6 +/- 12.1 years). NT-proBNP level, 6-minute walking test (6MWT), and transthoracic echocardiography (TTE) for the assessment of RV overload were performed. Serum NT-proBNP exceeded the reference value of 125 pg/mL in 31 (61%) SSc patients. The mean serum log NT-proBNP concentration in SSc was higher than in controls (2.138 +/- 0.527 vs. 1.634 +/- 0.420 pg/mL, p < 0.001). 13 (25%) SSc patients have tricuspid regurgitation peak gradient (TRPG) exceeding 31 mmHg reflecting pulmonary arterial hypertension (PAH). The SSc presented other echocardiographic signs of RV overload. Mean 6MWT distance was shorter in SSc than in controls (528 +/- 100 vs. 617 +/- 80 m, p < 0.001). NT-proBNP level correlated positively with TRPG, RV diameter, RV Tei index and negatively with 6MWT distance. ROC analysis identified >115 pg/ml as the best NT-proBNP threshold predicting PAH for SSc patients (sensitivity 92%, specificity 44%). Results of our study suggest that NT-proBNP measurement is a useful screening method for PAH in SSc patients. Since elevated plasma NT-proBNP level reflects the degree of right ventricular overload and limitation of exercise capacity, abnormal NT-proBNP levels should imply further evaluation including echocardiography.

Efficacy and safety of cyclophosphamide, azathioprine, and cyclosporine (ciclosporin) as adjuvant drugs in pemphigus vulgaris.

BACKGROUND: Pemphigus vulgaris is a potentially life-threatening, autoimmune bullous disease of the skin and mucous membranes. Most commonly, the disease is treated with prednisone in combination with an immunosuppressant agent, frequently referred to as adjuvant drug. However, there is no consensus regarding the first-choice adjuvant drug for the treatment of pemphigus vulgaris or the recommended dosage. OBJECTIVE: To evaluate the efficacy and safety of prednisone as monotherapy and in combination with the three most popular adjuvant agents - azathioprine, cyclosporine (ciclosporin), and cyclophosphamide - in the treatment of pemphigus vulgaris. METHODS: This was a retrospective study with a follow-up of 7-21 years. The study was conducted in an academic hospital with an outpatient division for patients with bullous diseases. A total of 101 patients with moderate-to-severe mucocutaneous pemphigus vulgaris were included in the study. For assessment of disease severity a 'pemphigus score,' based on the percentage of involved skin or oral mucous membranes, was developed. At treatment initiation the average pemphigus score was comparable in all treated groups of patients. Four treatment regimens were evaluated: oral prednisone at an initial dose of 100mg (1.1-1.5 mg/kg) per day as monotherapy, and prednisone combined with adjuvant drugs, i.e. oral azathioprine at a dose of 100mg (1.1-1.5 mg/kg) per day; cyclosporine (ciclosporin) at a dose of 2.5-3 mg/kg/day; or cyclophosphamide at a dose of 100mg (1.1-1.5 mg/kg) per day. The main outcome measures were average time to clinical remission, average time to immunologic remission (non-detectable circulating pemphigus vulgaris antibodies), proportion of patients who remained free of clinical relapse within 5 years after discontinuation of therapy, time from treatment discontinuation until first relapse, and incidence of adverse effects. RESULTS: The average (+/- SD) time to clinical remission was 7.2 +/- 13.1 months in patients who received prednisone monotherapy, 6.8 +/- 10.5 months in patients receiving additional azathioprine, 8.1 +/- 11.8 months in the cyclosporine group, and 4.9 +/- 6.9 months (which was significantly shorter than all other treatment groups, p < 0.05) in patients receiving cyclophosphamide. The average (+/- SD) times to immunologic remission were 33 +/- 27 months, 28 +/- 24 months, 30 +/- 21 months, and 23 +/- 17 months for prednisone monotherapy, azathioprine, cyclosporine, and cyclophosphamide, respectively. The proportions of patients who remained free of clinical relapse within 5 years after discontinuation of therapy were 55%, 50%, 43%, and 69% for prednisone monotherapy, azathioprine, cyclosporine, and cyclophosphamide, respectively. In patents who experienced relapse, the average (+/- SD) time from treatment discontinuation to clinical relapse was 10.50 +/- 6.86 months in patients receiving prednisone monotherapy, 16.40 +/- 17.36 months in the azathioprine group, 12.44 +/- 6.48 months in the cyclosporine group, and 21.16 +/- 20.13 months in the cyclophosphamide group. The safety profiles of all treatment regimens were comparable. CONCLUSION: Oral prednisone with cyclophosphamide is the most effective treatment for pemphigus vulgaris. All therapy regimens had a similar safety profile. In our opinion, cyclophosphamide at a dose of 1.1-1.5 mg/kg/day should be the adjuvant drug of choice in the treatment of moderate-to-severe pemphigus vulgaris.

Fibrodysplasia ossificans progressiva.

Fibrodysplasia ossificans progressiva, a rare genetic disabling disease characterized by heterotopic bone formation, is of special interest for general medicine since the bone morphogenetic proteins (especially BMP-4) involved in its pathogenesis are known to play a role in skeletal morphogenesis, and the gene antagonist to BMP-4 noggin might be useful in preventing lamellar bone formation. We present two cases with characteristic musculo-skeletal abnormalities and histopathological features (inflammatory infiltrates which destroyed muscle tissue replacing it by proliferating fibroblasts). In one patient due to high activity of fibroblasts, the histopathologic pattern appeared to be atypical and the lesion was recognized by a general pathologist as sarcoma. The other patient, due to the symmetrical induration of sternocleidomastoid muscles, was primarily recognized as scleredema. We stress the diagnostic importance of skeletal abnormalities (hallux valgus and others), and discuss differentiation from progressive osseous heteroplasia (POH) and congenital or acquired localized cutaneous and muscle ossifications which have a much better prognosis, as well as Albright's hereditary osteodystrophy, which differs by the presence of various systemic abnormalities. A study of FOP might provide an important clue to the genetic molecular mechanism of bone formation, development of heterotopic bone and a possible prevention by molecular manipulation with the gene responsible for bone morphogenetic proteins and their antagonists.

Smad1 pathway is activated in systemic sclerosis fibroblasts and is targeted by imatinib mesylate.

OBJECTIVE: Activation of Smad1 signaling has recently been implicated in the development of fibrosis. The goal of the present study was to gain further insights into activation of the Smad1 pathway in fibrosis in systemic sclerosis (SSc) and to determine whether this pathway is targeted by the antifibrotic drug imatinib mesylate. METHODS: Levels of phosphorylated Smad1 and total Smad1 were examined in SSc and control skin biopsy samples by immunohistochemistry and in cultured fibroblasts by Western blotting. Activity of the CCN2 promoter was examined by a luciferase reporter gene assay. Interactions of Smad1 with the CCN2 promoter were examined by in vitro and in vivo DNA binding assays. Expression of the nonreceptor tyrosine kinase c-Abl and Smad1 was blocked using respective small interfering RNA. RESULTS: Total and phosphorylated Smad1 levels were significantly elevated in SSc skin biopsy samples and in cultured SSc fibroblasts and correlated with elevated CCN2 protein and CCN2 promoter activity. DNA binding assays demonstrated that Smad1 was a direct activator of the CCN2 gene. Small interfering RNA-mediated depletion of Smad1 in SSc fibroblasts normalized the production of CCN2 and collagen. Imatinib mesylate blocked activation of the Smad1 pathway in transforming growth factor beta-stimulated control fibroblasts and reversed activation of this pathway in SSc fibroblasts. Likewise, blockade of c-Abl abrogated activation of the Smad1 pathway in SSc fibroblasts. CONCLUSION: Our findings demonstrate that activation of Smad1 signaling occurs in a subset of SSc patients and contributes to persistent activation of SSc fibroblasts. Demonstration that the Smad1/CCN2 pathway is blocked by imatinib mesylate further clarifies the mechanism of the antifibrotic effects of this compound. This study suggests that SSc patients with activated Smad1 signaling may benefit from imatinib mesylate treatment.

Advanced systemic sclerosis complicated by pulmonary hypertension and complete atrioventricular block: a case report.

BACKGROUND: Systemic sclerosis (SSc) is a connective tissue disorder of unknown etiology characterized by fibrosis of the skin and visceral organs, in which the heart is frequently (40-70% of patients) and severely involved. Pulmonary hypertension affects 10-15% of patients with SSc and is one of the most important complications adversely influencing their survival. CASE REPORT: The case report presents a 59-year-old male patient with advanced systemic sclerosis whose initial examination revealed pulmonary hypertension, rhythm and atrioventricular conduction disturbances, and elevated level of NT-proBNP. After six months the patient deteriorated; an increase in NT-proBNP level and progression of pulmonary hypertension were observed. CONCLUSIONS: The described case is followed by a discussion of cardiovascular involvement in systemic sclerosis and emphasizes that heart involvement in SSc may have very serious clinical implications.

Gene profiling of scleroderma skin reveals robust signatures of disease that are imperfectly reflected in the transcript profiles of explanted fibroblasts.

OBJECTIVE: To determine whether biopsy specimens obtained from systemic sclerosis (SSc) lesions show a distinctive gene profile, whether that gene profile is maintained in fibroblasts cultured from SSc skin biopsy specimens, and whether results from tissue obtained from multiple clinical centers can be combined to yield useful observations in this rare disease. METHODS: Biopsy samples and passaged fibroblasts were stored in RNAlater solution prior to processing for RNA. RNA from SSc and control skin biopsy specimens, as well as SSc and control explanted passage 4 fibroblasts, from 9 patients and 9 controls was hybridized to Affymetrix HG-U133A arrays. Data were analyzed using the BRB ArrayTools system. When appropriate, findings were followed up with immunohistochemical analysis or TaqMan studies. RESULTS: Biopsy samples obtained from patients with SSc had a robust and distinctive gene profile, with approximately 1,800 qualifiers distinguishing normal skin from SSc skin at a significant level. The SSc phenotype was the major driver of sample clusters, independent of origin. Alterations in transforming growth factor beta and Wnt pathways, extracellular matrix proteins, and the CCN family were prominent. Explanted fibroblasts from SSc biopsy samples showed a far smaller subset of changes that were relatively variable between samples, suggesting that either nonfibroblast cell types or other aspects of the dermal milieu are required for full expression of the SSc phenotype. CONCLUSION: SSc has a distinct gene profile that is not confounded by geographic location, indicating that extended multicenter studies may be worthwhile to identify distinct subsets of disease by transcript profiling. Explanted SSc fibroblasts show an incomplete reflection of the SSc phenotype.

Alterations of basement membrane zone and cutaneous microvasculature in morphea and extragenital lichen sclerosus.

The aim of this study was to compare alterations of the basement membrane zone (BMZ) and to visualize changes within the skin vascular network in morphea and extragenital lichen sclerosus with the use of laser scanning confocal microscopy. This work was performed in eight plaques of morphea (three active and five inactive) and eight of lichen sclerosus (three of short duration and five long-lasting). Biopsy specimens from six healthy individuals served as controls. The biopsies were cut into 40-microm-thick sections, labeled with antibodies against beta4-intergin (a lamina lucida marker), collagen IV, and the N-terminal end of collagen VII (lamina densa markers) and C-terminal end of collagen VII (a sublamina densa marker) and studied using laser scanning confocal microscopy. Three-dimensional reconstruction of various regions of the BMZ showed a decreased number and size of the dermal papillae both in morphea and lichen sclerosus compared with normal skin. In morphea, the continuity of the BMZ at the level of lamina lucida, lamina densa, and sublamina densa was preserved whereas in LS numerous invaginations and holes were present in the BMZ at the level of the lamina lucida and lamina densa. Thus the alterations of the BMZ in morphea differ from those in lichen sclerosus. Three-dimensional reconstruction of the skin vascular network showed increased angiogenesis only in the early inflammatory stage of morphea, whereas in inactive morphea and lichen sclerosus various numbers of enlarged vessels were visible. The changes in the vascular network in morphea appear to be related to the activity of the disease.

Generalized eruptive keratoacanthoma of Grzybowski: follow-up of the original description and 50-year retrospect.

We report a follow-up of the original case of eruptive multiple keratoacanthoma (KA) described by Grzybowski in 1950 which did not show malignant transformation within 16 years after the onset of the disease in spite of a very widespread cutaneous involvement. There was no associated internal malignancy or any systemic disease either, and the patient died of a myocardial infarction unrelated to his cutaneous disorder. This case followed up for such a long time provides further confirmation that this variety of KA does not show invasive growth and usually does not progress into squamous cell carcinoma.

Progressive facial hemiatrophy: central nervous system involvement and relationship with scleroderma en coup de sabre.

OBJECTIVE: To investigate the relationship of progressive facial hemiatrophy (PFH) and scleroderma en coup de sabre by establishing the presence and type of central nervous system (CNS) involvement in both diseases and the possible coexistence of PFH with scleroderma in other body sites. METHODS: We divided 19 cases of PFH into 2 groups: group 1 in which atrophies were preceded by cutaneous indurations (n = 10) and group 2 with no precedent indurations (n = 9). The third group consisted of 7 cases of scleroderma en coup de sabre with no PFH features. Clinical and laboratory investigations included indirect immunofluorescence for antinuclear antibodies, and routine neurological examination involved electroencephalography, magnetic resonance imaging (MRI) before and after contrast application to evaluate the integrity of blood-brain barrier, angio-MRI to evaluate intracranial blood vessel anomalies, and 99mTc-HM-PAO-SPECT to evaluate regional cerebral blood flow (CBF). RESULTS: We found similar anomalies in all 3 groups. MRI did not show abnormality in 2 out of 9 PFH cases preceded by indurations, in 5 out of 9 cases not preceded by indurations, and in all 7 cases of scleroderma en coup de sabre, including 5 patients, in whom the CBF was found to be diminished. In single cases of groups 1 and 2, SPECT was normal despite some MRI abnormalities. Angio-MRI was not contributory since the same abnormalities of Willis circle were found in normal controls. In single cases of both PFH groups, MRI with contrast disclosed some damage of the blood-brain barrier. CONCLUSION: Our results suggest frequent CNS involvement in PFH cases, regardless of the time of presentation of cutaneous indurations, with or without coexistent plaques of localized scleroderma in other locations. This indicates a close relationship between PFH and scleroderma en coup de sabre. The detection of abnormal SPECT by normal MRI in some cases of PFH and scleroderma en coup de sabre is of practical importance. This indicates the usefulness of SPECT in studying both PFH and scleroderma en coup de sabre.

Alterations of basement membrane zone in bullous and non-bullous variants of extragenital lichen sclerosus.

The aim of the study was to compare alterations of various regions of the basement membrane zone (BMZ) in lichen sclerosus (LS) using laser scanning confocal microscopy. The study included three cases of bullous LS, one case of bullous LS that developed in the course of graft-versus-host disease (GVHD), and six cases of non-bullous LS. Three cases of morphea served as a control. Biopsies from patients' skin and control biopsies from normal human skin were cut into 30-microm thick slides and labeled with antibodies against beta4-intergin (lamina lucida marker), collagen IV, and the N-terminal end of collagen VII (lamina densa markers) and the C-terminal end of collagen VII (sublamina densa marker) using routine immunofluorescence (IF). Three-dimensional (3D) reconstruction of various regions of the BMZ showed a decrease in the number and size of the dermal papillae in LS and morphea as compared with normal skin. In LS numerous invaginations and holes were present in the BMZ at the level of the lamina lucida and lamina densa. Computer animation of 3D projections revealed that the thickness of the lamina densa observed under the light microscopy is an optical artifact dependent on periodical tortion of the lamina densa along its axis. Torsions and invaginations of the BMZ are equally responsible for the phenomenon of artificial reduplication of the lamina densa observed at the ultrastructural level. IF labeling with antibody against the N-terminal end of collagen VII disclosed the presence of a large hole (up to 25 microm) in the lamina densa and the presence of granular material in deep dermis suggestive of partial degradation of lamina densa at the level of anchoring fibers. An IF mapping study showed blister formation below the lamina densa in three patients with bullous LS, whereas in a case of LS associated with GVHD, a blister formed through the basal layer of the epidermis. In morphea, there was flattening of BMZ at the level of lamina lucida, lamina densa, and sublamina densa but the continuity of BMZ was preserved. Three-dimensional reconstruction of dermal-epidermal junction in LS revealed alterations of the BMZ, most pronounced at the level of the lamina densa and sublamina densa.

An increased transforming growth factor beta receptor type I:type II ratio contributes to elevated collagen protein synthesis that is resistant to inhibition via a kinase-deficient transforming growth factor beta receptor type II in scleroderma.

OBJECTIVE: Aberrant transforming growth factor beta (TGFbeta) signaling has been implicated in the pathogenesis of scleroderma (systemic sclerosis [SSc]), but the contribution of specific components in this pathway to SSc fibroblast phenotype remains unclear. This study was undertaken to delineate the role of TGFbeta receptor type I (TGFbetaRI) and TGFbetaRII in collagen overexpression by SSc fibroblasts. METHODS: Primary dermal fibroblasts from SSc patients and healthy adults were studied (n = 10 matched pairs). Adenoviral vectors were generated for TGFbetaRI (AdTGFbetaRI), TGFbetaRII (AdTGFbetaRII), and kinase-deficient TGFbetaRII (AdDeltakRII). TGFbetaRI basal protein levels were analyzed by (35)S-methionine labeling/immunoprecipitation and immunohistochemistry. Type I collagen and TGFbetaRII basal protein levels were analyzed by Western blot and newly secreted collagen by (3)H-proline incorporation assay. RESULTS: Analysis of endogenous TGFbetaRI and TGFbetaRII protein levels revealed that SSc TGFbetaRI levels were increased 1.7-fold (P = 0.008; n = 7) compared with levels in healthy controls, while TGFbetaRII levels were decreased by 30% (P = 0.03; n = 7). This increased TGFbetaRI:TGFbetaRII ratio correlated with SSc collagen overexpression. To determine the consequences of altered TGFbetaRI:TGFbetaRII ratio on collagen expression, healthy fibroblasts were transduced with AdTGFbetaRI or AdTGFbetaRII. Forced expression of TGFbetaRI in the range corresponding to elevated SSc TGFbetaRI levels increased basal collagen expression in a dose-dependent manner, while similar TGFbetaRII overexpression had no effect, although transduction of fibroblasts at higher multiplicities of infection led to a marked reduction of basal collagen levels. Blockade of TGFbeta signaling via AdDeltakRII resulted in approximately 50% inhibition of basal collagen levels in healthy fibroblasts and in 5 of 9 SSc cell lines. A subset of SSc fibroblasts (4 of 9 cell lines) was resistant to this treatment. SSc fibroblasts with the highest levels of TGFbetaRI were the least responsive to collagen inhibition via DeltakRII. CONCLUSION: This study indicates that an increased TGFbetaRI:TGFbetaRII ratio may underlie aberrant TGFbeta signaling in SSc and contribute to elevated basal collagen production, which is insensitive to TGFbeta signaling blockade via DeltakRII.

Persistent down-regulation of Fli1, a suppressor of collagen transcription, in fibrotic scleroderma skin.

The molecular and cellular mechanisms that maintain proper collagen homeostasis in healthy human skin and are responsible for the dysregulated collagen synthesis in scleroderma remain primarily unknown. This study demonstrates that Fli1 is a physiological negative regulator of collagen gene expression in dermal fibroblasts in vitro and in human skin in vivo. This conclusion is supported by the analyses of mouse embryonic fibroblasts from Fli1(-/-), Fli1(+/-), and Fli1(+/+) mice. In cultured human and mouse fibroblasts Fli1 expression levels are inversely correlated with the collagen type I expression levels. These in vitro observations were validated in vivo. In healthy human skin Fli1 protein is expressed in fibroblasts and endothelial cells. Significantly, absence of Fli1 expression in individual fibroblasts correlates with elevated collagen synthesis. In contrast to healthy skin, Fli1 protein is consistently absent from fibroblasts and significantly reduced in endothelial cells in clinically involved scleroderma skin, which correlates with enhanced collagen synthesis in systemic sclerosis skin. This study supports the role of Fli1 as a suppressor of collagen transcription in human skin in vivo. Persistent down-regulation of Fli1 in scleroderma fibroblasts in vivo may directly contribute to uncontrolled matrix deposition in scleroderma skin.