Sphingomyelin Deacylase, the Enzyme Involved in the Pathogenesis of Atopic Dermatitis, Is Identical to the ß-Subunit of Acid Ceramidase.

A ceramide deficiency in the stratum corneum (SC) is an essential etiologic factor for the dry and barrier-disrupted skin of patients with atopic dermatitis (AD). Previously, we reported that sphingomyelin (SM) deacylase, which hydrolyzes SM and glucosylceramide at the acyl site to yield their lysoforms sphingosylphosphorylcholine (SPC) and glucosylsphingosine, respectively, instead of ceramide and/or acylceramide, is over-expressed in AD skin and results in a ceramide deficiency. Although the enzymatic properties of SM deacylase have been clarified, the enzyme itself remains unidentified. In this study, we purified and characterized SM deacylase from rat skin. The activities of SM deacylase and acid ceramidase (aCDase) were measured using SM and ceramide as substrates by tandem mass spectrometry by monitoring the production of SPC and sphingosine, respectively. Levels of SM deacylase activity from various rat organs were higher in the order of skin > lung > heart. By successive chromatography using Phenyl-5PW, Rotofor, SP-Sepharose, Superdex 200 and Shodex RP18-415, SM deacylase was purified to homogeneity with a single band of an apparent molecular mass of 43 kDa with an enrichment of > 14,000-fold. Analysis by MALDI-TOF MS/MS using a protein spot with SM deacylase activity separated by 2D-SDS-PAGE allowed its amino acid sequence to be determined and identified as the ß-subunit of aCDase, which consists of α- and ß-subunits linked by amino bonds and a single S-S bond. Western blotting of samples treated with 2-mercaptoethanol revealed that, whereas recombinant human aCDase was recognized by antibodies to the α-subunit at ~56 kDa and ~13 kDa and the ß-subunit at ~43 kDa, the purified SM deacylase was detectable only by the antibody to the ß-subunit at ~43 kDa. Breaking the S-S bond of recombinant human aCDase with dithiothreitol elicited the activity of SM deacylase with ~40 kDa upon gel chromatography. These results provide new insights into the essential role of SM deacylase expressed as an aCDase-degrading ß-subunit that evokes the ceramide deficiency in AD skin.

A case of endometrioid adenocarcinoma developing 8 years after conservative management for atypical polypoid adenomyoma.

•Endometrioid adenocarcinoma may develop during the long-term follow-up of APA.•Atypical polypoid adenomyoma is a precursor of endometrioid adenocarcinoma.•Careful follow-up is needed for the conservative management of APA.

Ovarian thecoma associated in the first trimester of pregnancy.

Ovarian thecoma is a relatively rare tumor which occurs before and after menopause. It is extremely rare that pregnancy is complicated with thecoma. Diagnosis of ovarian tumors during pregnancy is highly problematic due to difficulties in obtaining clinical manifestations, and treatment of these tumors poses an even greater challenge. Our patient was found to have estrogen-producing thecoma accompanied by accumulation of ascites in an early phase of pregnancy. The patient underwent abdominal surgery to remove the tumor on the 13th week of gestation. This resulted in disappearance of the ascites and a favorable clinical course. Diagnosis and treatment of ovarian thecoma occurring during pregnancy are discussed with relevant references.

Design and synthesis of peptide-based carboxylic acid-containing transition-state inhibitors of human neutrophil elastase.

In our search for a new agent, human neutrophil elastase (HNE) inhibitor, for the treatment of acute respiratory failure, we rationally designed and synthesized a series of peptide-based carboxylic acid-containing transition-state inhibitors. The presence of valyl moiety is found to be essential for potent in vitro inhibitory activity and also prevention of an undesirable toxicity. Of these, compound 9m has the most potent in vivo effect on HNE-induced lung hemorrhage in hamsters.