Effects of once-monthly minodronate versus risedronate in osteoporosis patients with rheumatoid arthritis: a 12-month randomized head-to-head comparison.

A head-to-head comparison of once-monthly oral bisphosphonates minodronate (MIN) and risedronate (RIS) in patients with rheumatoid arthritis (RA) demonstrated that MIN has the same effect as RIS on increase in bone mineral density (BMD) and a stronger effect on inhibition of bone resorption than RIS, suggesting that MIN is a promising treatment option for osteoporosis patients with RA. INTRODUCTION: To evaluate the effect of once-monthly oral MIN in patients with RA, a prospective, randomized, open-label, head-to-head comparison with once-monthly oral RIS was conducted. METHODS: A total of 83 patients with RA were randomly assigned to either once-monthly oral MIN 50 mg (n = 42) or once-monthly oral RIS 75 mg (n = 41). Serial BMD and bone turnover markers were measured and compared between the treatment groups. RESULTS: BMD (lumbar spine, total hip, femoral neck) increased significantly after 12 months of treatment with MIN (3.8, 2.0, and 2.2%, respectively, P < 0.05) and RIS (3.6, 1.9, and 1.9%, respectively, P < 0.05). There were no significant differences between the treatment groups. Percent changes of bone turnover markers from baseline to 12 months in the MIN group were significantly greater than those in the RIS group (TRACP-5b: - 36.3 vs - 19.3%, P < 0.05; NTX: - 27.1 vs - 17.3%, P < 0.05; BAP: -30.2 vs -19.4%, P < 0.05). CONCLUSIONS: The present study of RA patients demonstrated that MIN has the same effect as RIS on increase in BMD and a stronger effect on inhibition of bone resorption than RIS. The results suggest that MIN is a promising treatment option for osteoporosis patients with RA.

IκB kinase ß inhibitor IMD-0354 suppresses airway remodelling in a Dermatophagoides pteronyssinus-sensitized mouse model of chronic asthma.

BACKGROUND: Nuclear factor (NF)-κB is a transcription factor that regulates cytokine and chemokine production in various inflammatory diseases, including bronchial asthma. IκB kinase (IKK) ß is important for NF-κB activation in inflammatory conditions, and is possibly related to airway remodelling. Thus, inhibition of the IKKß-NF-κB pathway may be an ideal strategy for the management of airway remodelling. OBJECTIVE: We examined the effects of a newly synthesized IKKß inhibitor, IMD-0354, in a chronic allergen exposure model of bronchial asthma in mice. METHODS: A chronic mouse model was generated by challenge with house dust mite antigen (Dermatophagoides pteronyssinus). IMD-0354 was administrated intraperitoneally in therapeutic groups. Lung histopathology, hyperresponsiveness and the concentrations of mediators and molecules in supernatants of lung homogenates were determined. RESULTS: NF-κB activation was inhibited by prolonged periods of IMD-0354 administration. IMD-0354 reduced the numbers of bronchial eosinophils. IMD-0354 also inhibited the pathological features of airway remodelling, including goblet cell hyperplasia, subepithelial fibrosis, collagen deposition and smooth muscle hypertrophy. Inhibition of these structural changes by IMD-0354 was the result of the suppressing the production and activation of remodelling-related mediators, such as TGF-ß, via inhibition of IKKß. IMD-0354 inhibited IL-13 and IL-1ß production, and it restored the production of IFN-γ. It also ameliorated airway hyperresponsiveness. CONCLUSION: IKKß plays crucial roles in airway inflammation and remodelling in a chronic mouse model of asthma. A specific IKKß inhibitor, IMD-0354, may be therapeutically beneficial for treating airway inflammation and remodelling in chronic asthma.

Physical and functional association of the cbl protooncogen product with an src-family protein tyrosine kinase, p53/56lyn, in the B cell antigen receptor-mediated signaling.

To identify novel signal transducers involved in signaling mediated by the Src-family protein tyrosine kinases (PTKs), we used a yeast two-hybrid system with a probe corresponding to the regulatory region of p56lyn, a member of Src-family PTKs. One of the isolated clones contained the COOH-terminal 470 amino acid residues of p120c-cbl, the product of the cellular homologue of the v-cbl retroviral oncogene. p120c-cbl is a cytoplasmic protein with nuclear protein-like motifs. Here we show in vivo association of p120c-cbl with p53/56lyn. After stimulation of the B cell antigen receptor (BCR), p120c-cbl was rapidly tyrosine phosphorylated. Studies with lyn- or syk-negative chicken B cells demonstrated that p53/56lyn, but not p72syk, was crucial for tyrosine phosphorylation of p120c-cbl upon stimulation of the BCR. We also show the importance of p59fyn in tyrosine phosphorylation of p120c-cbl in the T-cell receptor-mediated signaling using fyn-overexpressing T cell hybridomas and splenic T cells from fyn-deficient mice. These results suggest that p120c-cbl is an important substrate of Src-family PTKs in the intracellular signaling mediated by the antigen receptors

Cbl suppresses B cell receptor-mediated phospholipase C (PLC)-gamma2 activation by regulating B cell linker protein-PLC-gamma2 binding.

Accumulating evidence indicates that the Cbl protein plays a negative role in immune receptor signaling; however, the mode of Cbl action in B cell receptor (BCR) signaling still remains unclear. DT40 B cells deficient in Cbl showed enhanced BCR-mediated phospholipase C (PLC)-gamma2 activation, thereby leading to increased apoptosis. A possible explanation for the involvement of Cbl in PLC-gamma2 activation was provided by findings that Cbl interacts via its Src homology 2 (SH2) domain with B cell linker protein (BLNK) after BCR ligation. BLNK is a critical adaptor molecule for PLC-gamma2 tyrosine phosphorylation through its binding to the PLC-gamma2 SH2 domains. As a consequence of the interaction between Cbl and BLNK, the BCR-induced recruitment of PLC-gamma2 to BLNK and the subsequent PLC-gamma2 tyrosine phosphorylation were inhibited. Thus, our data suggest that Cbl negatively regulates the PLC-gamma2 pathway by inhibiting the association of PLC-gamma2 with BLNK.

Effect of immunoglobulin G (IgG) interchain disulfide bond cleavage on efficacy of intravenous immunoglobulin for immune thrombocytopenic purpura (ITP).

Intravenous immunoglobulin (IVIG) has been used widely to treat immune thrombocytopenic purpura (ITP), but the mechanisms of its action remain unclear. We investigated the affinity for Fcγ receptors (FcγRs) and the thrombocytopenia-ameliorating effect of S-sulfonated gammaglobulin (SGG) and S-alkylated gammaglobulin (AGG), in comparison with unmodified gammaglobulin (GG), in a mouse ITP model. Cleavage of immunoglobulin (Ig)G interchain disulfide bonds by either S-sulfonation or S-alkylation did not decrease the affinity for FcγRIIA (CD32A) and FcγRIIB (CD32B), but did decrease the affinity for FcγRIA (CD64A) and FcγRIIIA (CD16A), presumably because of changes in H-chain configuration. The interchain disulfide bond cleavage decreased the affinity much more for mouse FcγRIV than for mouse FcγRIIB. The ability of AGG to ameliorate ITP was greatly diminished, while SGG, whose disulfide bonds are reconstituted in vivo, was as effective as GG. These results suggest that the interchain disulfide bonds are important for therapeutic effect. It is also suggested that the interaction of IVIG with the inhibitory receptor FcγRIIB is insufficient for effective amelioration of ITP and that, at least in this model, direct binding of IVIG to FcγRIIIA is also required.

Effect of femoral canal shape on mechanical stress distribution and adaptive bone remodelling around a cementless tapered-wedge stem.

OBJECTIVES: In total hip arthroplasty (THA), the cementless, tapered-wedge stem design contributes to achieving initial stability and providing optimal load transfer in the proximal femur. However, loading conditions on the femur following THA are also influenced by femoral structure. Therefore, we determined the effects of tapered-wedge stems on the load distribution of the femur using subject-specific finite element models of femurs with various canal shapes. PATIENTS AND METHODS: We studied 20 femurs, including seven champagne flute-type femurs, five stovepipe-type femurs, and eight intermediate-type femurs, in patients who had undergone cementless THA using the Accolade TMZF stem at our institution. Subject-specific finite element (FE) models of pre- and post-operative femurs with stems were constructed and used to perform FE analyses (FEAs) to simulate single-leg stance. FEA predictions were compared with changes in bone mineral density (BMD) measured for each patient during the first post-operative year. RESULTS: Stovepipe models implanted with large-size stems had significantly lower equivalent stress on the proximal-medial area of the femur compared with champagne-flute and intermediate models, with a significant loss of BMD in the corresponding area at one year post-operatively. CONCLUSIONS: The stovepipe femurs required a large-size stem to obtain an optimal fit of the stem. The FEA result and post-operative BMD change of the femur suggest that the combination of a large-size Accolade TMZF stem and stovepipe femur may be associated with proximal stress shielding.Cite this article: M. Oba, Y. Inaba, N. Kobayashi, H. Ike, T. Tezuka, T. Saito. Effect of femoral canal shape on mechanical stress distribution and adaptive bone remodelling around a cementless tapered-wedge stem. Bone Joint Res 2016;5:362-369. DOI: 10.1302/2046-3758.59.2000525.

Pressure-induced changes in the folded structure of lysozyme.

We demonstrate, for the first time in solution, that pressure induces changes in the overall folded structure of a protein (lysozyme). This was made possible by using a home-developed, on-line continuously variable pressure cell on a high resolution NMR spectrometer operating at 750 MHz. We could follow pressure-induced diamagnetic chemical shifts of more than 26 protons of lysozyme at variable pressure in the range of 1 to 2000 bar. The results indicate that the main effect of the pressure is a compaction of the hydrophobic core part of the protein consisting of bulky side-chains. The technique introduced here provides a general method with which one can probe microscopic internal flexibility of a protein in solution.

Mechanisms of glucocorticoid resistance in human leukemic cells: implication of abnormal 90 and 70 kDa heat shock proteins.

The unliganded glucocorticoid receptor is a multi-oligomer complex consisting of a ligand-binding protein with which two 90 kDa heat shock proteins (hsp90s) are associated. Upon binding of glucocorticoid to the receptor, the ligand-binding protein, which dissociated from hsp90s, enters the nucleus, binds to a specific site in DNA, and thus transmits signal(s). The 70 kDa heat shock protein (hsp70) also works as a molecular chaperone when the ligand-binding protein enters the nucleus. Regarding the mechanisms of glucocorticoid resistance, a decreased expression of glucocorticoid receptor and a mutant protein with low ligand binding affinity have been reported. In the present study, to address other mechanisms of glucocorticoid resistance, we examined the expression of hsp90 and hsp70 in addition to the number of glucocorticoid-binding sites and their affinity using glucocorticoid-sensitive and -resistant human leukemic cell lines. We showed that two of nine resistant cell lines with normal glucocorticoid-binding proteins express aberrant hsp90 and extremely low hsp70, while another seven resistant cell lines had decreased binding sites with normal hsps. These results suggest that there are at least two independent mechanisms of glucocorticoid resistance in human leukemic cell lines: the decreased ligand-binding sites and the abnormal hsps expression.

Expression of thrombopoietin receptor and its functional role in human B-precursor leukemia cells with 11q23 translocation or Philadelphia chromosome.

Thrombopoietin (TPO) is a hematopoietic growth factor which plays a central role in normal megakaryocytopoiesis and thrombopoiesis. Although the interaction between TPO and its receptor c-Mpl encoded by the c-mpl gene is now known to be implicated in the proliferation and/or differentiation of abnormal myeloid cells and normal hematopoietic stem cells, little is known about a role of the TPO/c-Mpl system in lymphoid leukemia cells. In the present study, we first examined the expression of c-mpl/c-Mpl in 23 human lymphoid leukemic cell lines (T-lineage 4, B-lineage 19) using three distinct methods. The c-mpl mRNA was detectable in as many as 20 cell lines (T-lineage 3, B-lineage 17) by reverse transcriptase-polymerase chain reaction, but its translated product, c-Mpl, was demonstrable by Western blot only in B-lineage cell lines. Flow cytometric analysis revealed the surface c-Mpl expression in 13 of 17 B-lineage cell lines, but its higher expression (>40%) was restricted in nine B-precursor cell lines, eight of which had 11q23 translocation or Philadelphia chromosome (Ph1). We also demonstrated that two of eight cell lines with 11q23 translocation or Ph1 exhibited a significant proliferative response to TPO in the 3H-thymidine uptake and colony-forming assays. Triggering of these cell lines by TPO transiently up-regulated tyrosine phosphorylation of JAK-2 and Shc, indicating that their receptor is functional. Primary leukemia cells separated from patients with B-precursor acute lymphoblastic leukemia with Ph1 or 11q23 translocation also showed the surface c-Mpl expression and a significant responsiveness to TPO. These results suggest that the TPO/c-Mpl interaction may play a physiological role in the growth regulation of B-precursor leukemia cells particularly with specific chromosomal abnormalities.

Leukemic cells with 11q23 translocations express granulocyte colony-stimulating factor (G-CSF) receptor and their proliferation is stimulated with G-CSF.

We report a 20-month-old boy with acute lymphoblastic leukemia with the 11q23 translocation whose blasts markedly increased in peripheral blood after intravenous granulocyte colony-stimulating factor (G-CSF) administration, but disappeared after stopping G-CSF. The in vitro study showed that the leukemic cells separated from this patient expressed G-CSF receptor (G-CSFR) and an addition of G-CSF stimulated their proliferation by 3H-thymidine incorporation assay (stimulation index, 4.9). To clarify whether or not leukemic cells with 11q23 translocations generally express G-CSFR and show proliferative response to G-CSF, we performed the similar in vitro experiments using eight leukemic cell lines with 11q23 translocations. We found that all cell lines examined expressed G-CSFR (20-98%) and proliferation of seven leukemic cell lines was significantly enhanced in response to G-CSF (stimulation index >1.5 in five cell lines), suggesting a possible participation of the G-CSF/G-CSFR interaction in the process of growth regulation of leukemic cells with 11q23 translocations.

The JAK2 inhibitor AG490 predominantly abrogates the growth of human B-precursor leukemic cells with 11q23 translocation or Philadelphia chromosome.

The Janus kinase (JAK) family is one of intracellular protein tyrosine kinases (PTKs) present in hematopoietic and lymphoid cells and has been shown to play a crucial role in a variety of biological responses. It was reported that a human B-precursor leukemic cell line was potently inhibited in its proliferation by one of synthetic PTK inhibitors (tyrphostins), AG490, via anti-JAK2 activity. However, no extensive studies about it have been performed. In the present study, we tested 16 human lymphoid leukemic cell lines (B-precursor, 12; T cell, four) for their sensitivity to AG490 using 3H-thymidine incorporation and colony formation assays, and found that B-precursor cell lines with 11q23 translocation or Philadelphia chromosome (Ph1) whose JAK2 proved to be constitutively phosphorylated were predominantly sensitive to AG490 at a concentration that has few inhibitory effect on normal hematopoiesis. We first revealed the association of JAK2 with BCR-ABL in Ph1-positive cell lines and with Bruton's tyrosine kinase (BTK) in cell lines with 11q23 translocation by coimmunoprecipitation experiments. Of interest, AG490 markedly down-regulated phosphorylation of JAK2, but rather transiently up-regulated phosphorylation of BCR-ABL and BTK, suggesting direct implication of AG490 in the process of the JAK2 dephosphorylation. These results indicate that AG490 exerts a potent inhibitory activity to B-precursor leukemia with specific chromosomal abnormalities, and a therapeutic approach using AG490 is expected.

Participation of granulocyte colony-stimulating factor in the growth regulation of leukemia cells from Philadelphia chromosome-positive acute leukemia and blast crisis of chronic myeloid leukemia.

Granulocyte colony-stimulating factor (G-CSF) has been shown to support the growth of multipotential hematopoietic stem cells in addition to the cells of neutrophilic lineage. Philadelphia chromosome (Ph1)-positive leukemia has its origin in the hematopoietic stem cell. In the present study, we demonstrated that the proliferation of leukemic cells from chronic myeloid leukemia in blast crisis (CML-BC) and Ph1-positive acute lymphoblastic leukemia (ALL) cases is frequently stimulated with G-CSF in vitro. We next studied a total of 12 leukemic cell lines established from CML-BC (n= 6) and Ph1-positive acute leukemia (n= 6): four 'myeloid', five 'biphenotypic', and three 'lymphoid' types. All cell lines expressed G-CSF receptor (G-CSFR) in flow cytometric analysis, but their proliferative response to G-CSF in 3H-thymidine incorporation assay varied. The 'biphenotypic' cell lines expressed G-CSFR at higher levels and showed the most pronounced response to G-CSF. The 'lymphoid' cell lines showed intermediate G-CSFR expression with the modest response to G-CSF. Unexpectedly, 'myeloid' cell lines showed lower G-CSFR expression and lower G-CSF response compared with 'biphenotypic' cell lines. In three of four 'myeloid' cell lines, proliferation was partially inhibited by an addition of anti-G-CSF neutralizing monoclonal antibody into culture medium. Further, the % inhibition of 3H-thymidine uptake of cell lines positively correlated with the amount of their intracellular G-CSF measured by enzyme immunoassay, suggesting an autocrine growth mechanism via the G-CSF/G-CSFR interaction. These results suggest that G-CSF play an important role in the growth regulation of leukemia cells from Ph1-positive acute leukemia and CML-BC.

The KOR-SA3544 antigen predominantly expressed on the surface of Philadelphia chromosome-positive acute lymphoblastic leukemia cells is nonspecific cross-reacting antigen-50/90 (CD66c) and invariably expressed in cytoplasm of human leukemia cells.

We previously reported a novel monoclonal antibody KOR-SA3544 which predominantly reacted with a surface antigen (sSA3544) expressed on Philadelphia chromosome (Ph1)-positive acute lymphoblastic leukemia (ALL). In the present study, we demonstrate that the antibody specifically recognized nonspecific cross-reacting antigen (NCA)-50/90 (CD66c), one of the carcinoembryonic antigen (CEA)-related glycoproteins encoded by a member of the CEA gene family. In addition, we show that the SA3544 antigen (NCA-50/90) was invariably expressed in cytoplasm of all of the human leukemic cell lines examined (sSA3544-positive B-lymphoid two, sSA3544-negative T or B-lymphoid and non-lymphoid 24) regardless of the presence or absence of surface expression of this antigen. Immunoelectromicroscopic examination revealed that the cytoplasmic antigen was mainly present in granules in sSA3544-positive leukemia cells, whereas it was diffusely present in cytosol in sSA3544-negative leukemia cells. Thus, among members of the CEA family, NCA-50/90 was first demonstrated to be expressed not only on the surface of some leukemia cells, but also in cytoplasm of various types of leukemia cells.

p16/MTS1/INK4A gene is frequently inactivated by hypermethylation in childhood acute lymphoblastic leukemia with 11q23 translocation.

The p16 gene encoding a specific inhibitor of cyclin-dependent kinases 4 and 6 has been reported to be inactivated at a variety of rates in malignant tumors. We studied frequency and mechanism of inactivation of the p16 gene in various types of childhood acute lymphoblastic leukemia (ALL) using 36 leukemic cell lines established from children (B precursor-ALL, 28; B-ALL/Burkitt's lymphoma, 3; and T-ALL, 5). On Southern blot, homozygous deletions or hemizygous deletions with rearrangement were detected in 14 cell lines. The expression of p16 protein was not observed on Western blot in 18 of 22 cell lines with intact p16 gene, but induced in 16 cell lines after treatment with the demethylating agent, indicating the silencing of the p16 gene by hypermethylation. Of note, the p16 gene was inactivated by hypermethylation of the 5' CpG island in nine of nine cell lines with 11q23 translocation, but was restored with the treatment of the demethylating agent. Partial methylation of the p16 gene was also demonstrated in three of eight primary leukemia samples with this translocation, suggesting that the p16 gene inactivation by hypermethylation might play a role in the leukemogenesis and disease progression of ALL with 11q23 translocation.

The cystine-rich envelope protein from human epidermal stratum corneum cells.

A cystine-rich protein has been extracted from the membrane region of stratum corneum cells with 50 mM Tris-HCl buffer, pH 7.3. The protein has been purified by molecular sieve chromatography, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and preparative isoelectric focusing. An antibody, raised to the purified protein, was located in the cell membrane region in the stratum spinosum, stratum granulosum, and the inner part of the stratum corneum. In addition, the antibody also reacted with the protein extracted from the outer part of the stratum corneum by the immunoblotting method. Amino acid analysis of the protein revealed a distribution of 4.3% cystine residues, 9% lysine, 18.5% glycine, and 12.6% glutamic acid residues. The isoelectric point was found to be 4.8 and the molecular weight of the protein was 16,000.

Human hematoxylin-stainable protein of keratohyalin granules origin. I. Extraction and purification.

A human hematoxylin-stainable protein (HSP) was extracted from the massive stratum corneum of epidermal cysts. This protein was purified in two steps; first, through preparative isoelectric focusing, and, second, by affinity column chromatography bound with the specific, monoclonal antibody to keratohyalin granules (Ted-H-1). In sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the purified HSP consisted of two proteins (70 and 62 kilodaltons [kd]), but only the 62-kd protein was detected in the 15,000 g supernatant fraction of the extract using the immunoblotting technique. The amino acid composition of the purified HSP included 30% glycine, 15% serine, 12% glutamic acid, and 4% ornithine, but only 2.3% histidine. Using the indirect immunofluorescent technique, observation showed that the monoclonal antibody, Ted-H-1, to the HSP, formed as a result of the partially purified antigen, was located in three places: 1) the keratohyalin granules; 2) in the cell membrane region of the lower part of the stratum corneum of the skin samples (forearm, cheek, and back); and 3) the keratohyalin granules in the follicular epithelium and on the trichohyalin granules. Reaction product was not seen in either the acrosyringium or in the plantar epidermis. As two positively reacted proteins with the Ted-H-1 were detected in the Tris-HCl extract from the plantar stratum corneum by the immunoblotting assay, however, the above negative result in the indirect immunofluorescent studies may be due to the masking of the antigenic site of keratohyalin granules in vivo. This hematoxylin-stainable protein was synthesized as one component of the keratohyalin granules in the stratum granulosum and may have been transferred to the stratum corneum cell membrane region.

The water-holding capacity of the stratum corneum measured by 1H-NMR.

The amount of bound water in the stratum corneum of the hairless rat was measured by using proton nuclear magnetic resonance (1H-NMR) spectrometry in the temperature range of -5 degrees C to -30 degrees C. A decrease in the bound water content was observed when the stratum corneum was extracted using water, a mixed solvent of chloroform:methanol (2:1), or a 1% sodium dodecyl sulfate (SDS) aqueous solution. However, extraction using a mixed solvent of acetone:ether (1:1) did not change the bound water content at temperatures above -20 degrees C. The lipids extracted by acetone:ether-extraction method consisted of sebaceous gland lipids, cholesterol, free fatty acids, and ceramides. In contrast, the lipids extracted by chloroform:methanol-extraction method contained more polar lipids such as sphingomyelin, which had the same amount of bound water in itself as that of the water-extracted stratum corneum. These results suggest that the polar lipids soluble in the chloroform and methanol mixture may contribute to enhance the bound water content. Therefore, it is hypothesized that the water-holding capacity of the stratum corneum is dependent on both the hygroscopic components such as the natural moisturizing factor (NMF) and the polar lipids, such as sphingolipids, existing in the intercellular spaces of the stratum corneum.

Localization of sphingomyelinase in lesional skin of atopic dermatitis patients.

Because it has been suggested that the majority of the activity hydrolysing [N-methyl-14C] sphingomyelin is due to sphingomyelin acylase in the lesional skins of atopic dermatitis (AD), in this study we used immunologic techniques to localize and quantitate sphingomyelinase in AD lesional and normal skin. A polyclonal antibody raised against a synthetic polypeptide corresponding to a portion of the amino acid sequence deduced from the cDNA of human acid sphingomyelinase, cross-reacted with a 58 kDa, pI 5.8 human epidermal protein in an immunoblot analysis. The 58 kDa protein-rich fraction, partially purified by immunoprecipitation, converted [N-methyl-14C]-sphingomyelin to 14C-phosphorylcholine and ceramides. The reaction products were immunohistochemically observed in the intercellular domain from the upper spinous cell layer to the upper stratum corneum cell layers in the lesional skin of AD patients. Immunoelectron-microscopically, gold particles appeared to be concentrated in the intercellular domains of the granular-upper stratum corneum cells in the lesional skin of AD patients. The total amount of the 58 kDa protein in a 7 mm2 area of the skin was measured by quantitative immunoblot analysis; and was slightly increased in the lesional skin samples [3.5 +/- 0.3 microg per 7 mm2 (n = 7)], as compared with the nonlesional skin samples of AD patients [2.8 +/- 0.19 microg per 7 mm2 (n = 10)] and with the normal skin samples [2.7 +/- 0.22 microg per 7 mm2 (n = 10)]. This difference (between the lesional skin of AD and the nonlesional skin of AD or the normal control) was significant (nonpaired student's t test, p < 0.05).

Inhibition of growth of melanoma cells by CD95 (Fas/APO-1) gene transfer in vivo.

Interaction of CD95 ligand with its cognate receptor CD95 induces apoptotic cell death. Alterations in this pathway within tumor cells can result in escape from apoptosis and from immune surveillance. Melanoma cells recently were found to escape an immune attack via high expression of CD95 ligand, thereby inducing apoptosis of activated T lymphocytes. When screening four human melanoma cell lines for expression of CD95 and CD95 ligand, respectively, an inverse correlation was found, i.e., cells expressing high levels for CD95 ligand (CD95L(high)) were almost negative for CD95 and vice versa. Since coexpression of CD95 and CD95 ligand may lead to apoptosis by autocrine suicide or fratricide, it was tested whether overexpression of CD95 in CD95L(high) melanoma cells results in apoptotic cell death. Upon transfection with a cytomegalovirus-promoter-driven expression vector encoding the CD95 gene, CD95L(high) melanoma cells underwent apoptosis at a much higher level than CD95L(low) melanoma cells. Apoptosis appeared to be due to the activation of CD95 as cell death was inhibited by cotransfection with a dominant negative mutant for the CD95 signaling protein, Fas-associated protein with death domain. Tumor progression of CD95L(high) melanoma cells transplanted into nude mice was significantly reduced when recipient animals were injected with liposomes containing the CD95 expression vector. As demonstrated by immunohistochemistry and TUNEL staining, in vivo transfected tumor cells expressed CD95 and underwent apoptotic cell death. Hence, this study indicates that delivery of the CD95 gene inhibits tumor growth in vivo and thus might be a therapeutic strategy to treat tumor cells that express high levels of CD95 ligand. J Invest Dermatol 115:1008-1014 2000

Decreased level of prosaposin in atopic skin.

In the skin of atopic dermatitis patients, the amount of ceramides in the stratum corneum is decreased. Although the cause of this decrease may be due to the higher activity of acylase, a decrease in the activity of sphingolipid activator proteins may also be the cause. A polyclonal antibody to saposin D, elicited by immunizing rabbits with the synthetic polypeptide from cDNA of saposin D, cross-reacted with a single 65-kDa epidermal protein of pI 5.6 in a 2-dimensional immunoblot study, suggesting that it was prosaposin, the precursor protein of saposin D, from its molecular weight and demonstrating its immunohistochemical localization in the innermost cell layers of the stratum corneum of the skin. The antigenic material was also observed in the epithelium of the esophagus, pneumocytes of the lungs, hepatocytes, and glandular cells of the stomach. Immunoelectron microscopy showed the antigenic material in the cytoplasm of the granular cells and the intercellular spaces, either between the stratum granulosum and the stratum corneum or on the stratum corneum cell envelope. By ELISA, the amount of the 65-kDa protein in the inner surface skin of the upper arm of atopic dermatitis patients (nonlesional skin) [4.1 +/- 2.0 microg per 7 mm2 (mean +/- SD), n = 10] was found to be significantly decreased (p < 0.05) to 66% of that in the normal control (6.2 +/- 1.5 microg per 7 mm2, n = 10). Therefore, the suppression of prosaposin synthesis may be related to the abnormal stratum corneum formation in atopic skin through lower activation of glucosylcerebrosidase or sphingomyelinase.