Since acne formation is a multistep process accelerated by androgens, we examined whether a new anti-acne antibiotic roxithromycin (RXM) may act as anti-androgen using transient transfection assays in human skin fibroblasts. The result showed no significant effect of 0.5, 1 and 5 microg/ml RXM on 10(-9) M R1881-induced androgen receptor (AR) transcriptional activity. While the cotransfection of exogenous ARA55, a novel AR coactivator, increased AR transactivation up to 2.59-fold, this increase was attenuated by 5 microg/ml RXM to 64.7%. Semiquantitative RT-PCR results showed that 0.1 mM H(2)O(2) treatment increased ARA55 mRNA expression level, indicating that reactive oxygen species increase the expression of ARA55 in skin. These results suggest that RXM may serve as anti-androgen only in the hypersensitive state to androgen, but not in the physiological state, through modulating end-organ hypersensitive condition to androgen possibly involving the pathway from reactive oxygen species to ARA55.

Androgen Antagonists↗

PubMed2001

A case of lichenoid purpura possibly caused by diltiazem hydrochloride.

A 65-year-old Japanese man presented with itchy purpuric lichenoid papules of six months' duration on his legs and buttock. A topical glucocorticoid ointment was not effective. The biopsy specimen histologically showed a dense lichenoid infiltration of lymphocytes and histiocytes into the dermoepidermal junction; red blood cells were seen in the infiltration. Based on the clinical and pathological findings, we diagnosed this case as lichenoid purpura of Gougerot-Blum. The lesions disappeared when the diltiazem hydrochloride that he had been taking was discontinued.

Aged↗

PubMed2001

Churg-Strauss syndrome involving medium-sized arteries.

A 69-year-old Japanese man suffered from bronchial asthma, atrial fibrillation, general fatigue, high fever, and weight loss of about 5 kg within a month. He also had intermittent claudication, a tingling feeling in his fingers and toes, and an ulcer on his toe. His laboratory data revealed leukocytosis with absolute eosinophilia. The patient was treated with predonisolone 30 mg daily. Although the ulcers healed once, the lesions recurred with tapering predonisolone. The patient visited us because of the ulcer on his toe. Physical examination showed a 2 cm ulcer surrounded by slight erythema on his right fourth toe. Magnetic resonance angiography detected tapering stenosis of the medium-sized arteries in both legs. A biopsy from his myocardium showed the infiltration of eosinophils into the myocardium. The neuron conduction rate of his lower leg was slower than that of the normal control, demonstrating mononeuritis. From these findings, we diagnosed this patient as Churg-Strauss syndrome.

Aged↗

PubMed2000

Lack of androgen receptor transcriptional activity in human keratinocytes.

Since detection of androgen receptor (AR) expression in keratinocytes by immunostaining is controversial, we investigated whether keratinocytes can act as androgen target cells using transient transfection assays. Chloramphenicol acetyltransferase (CAT) assays for the endogenous AR transcriptional activity in HaCaT keratinocytes indicated that DHT (10(-9)-10(-8) M) can induce less than 1.5-fold of mouse mammary tumor virus CAT, which is quite low, compared with 38-fold induction by 10(-7) M 1,25-dihydroxyvitamin D(3) of P450cc24-CAT. Furthermore, this low DHT-mediated induction could not be enhanced by the AR co-activators, ARA70 or ARA55. Western blotting analysis indicated that HaCaT and normal keratinocytes do not express AR protein. Transfection of exogenous AR into HaCaT keratinocytes, however, could install AR transcriptional activity, suggesting that HaCaT keratinocytes have all the necessary accessory factors for AR transcription activity. In conclusion, keratinocytes are unlikely to be target cells for androgen.

Animals↗

PubMed2000

Double involvement of extramammary Paget's disease in the genitalia and axilla.

We here reported a case of an 82-year-old man with double involvement of extramammary Paget's disease in the genitalia and axilla. Physical examination revealed erythema and reddish tumors on the pubic area and scrotum and irregular-shaped erythema on the left axilla. The skin biopsy sample from the genital area showed Paget's cells in the epidermis and upper dermis. The specimen from the left axilla showed Paget's cells scattered in the epidermis but not in the dermis.

Aged↗

PubMed2000

A case of lichen planus-like keratosis: deposition of IgM in the basement membrane zone.

An 81-year-old woman presented with a round erythematous macule with keratotic scales on her left hand. The skin specimen histologically showed hypergranulosis and apoptotic keratinocytes in the epidermis with lichenoid infiltration of lymphocytes. Parakeratosis seen in the hyperkeratotic cornified layer indicated lichen planus-like keratosis, as distinguished from lichen planus. Direct immunofluorescence study revealed the linear deposition of IgM in the basement membrane zone; IgG, IgA and C3 were not detected.

Aged↗

PubMed1999

Involvement of a rapamycin-sensitive pathway in CD40-mediated activation of murine B cells in vitro.

Activation of resting B cells requires an initial triggering of the B cell antigen receptor (BCR) and secondary stimuli through various cytokine receptors and B cell activation molecules including CD40. We found that activation of B cells through CD40 is selectively inhibited by an immunosuppressant drug, rapamycin. This effect of rapamycin on anti-CD40-mediated activation of B cells was observed using three different in vitro assays. Rapamycin suppressed the anti-CD40-induced proliferation of splenic B cells, suppressed differentiation to surface IgMhigh/IgDlow B cells, and inhibited an anti-CD40-mediated prevention of apoptosis induced by BCR cross-linkage of WEHI-231 cells. We next examined several known CD40 signal transduction pathways to identify the target of rapamycin in stimulated B cells. Rapamycin did not inhibit the activation of c-Jun N-terminal kinases (JNKs) induced by anti-CD40 stimulation nor the activation of immediate nuclear transcription factors of NF-kappaB. Therefore, rapamycin affects a novel element of the CD40 signal transduction pathway which influences the proliferation, differentiation, and prevention of apoptosis of B cells.

Androstadienes↗

PubMed1999

Cloning and characterization of androgen receptor coactivator, ARA55, in human prostate.

Androgen receptor (AR) is a hormone-activated transcriptional factor that can bind to androgen response elements and that regulates the transcription of target genes via a mechanism that presumably involves cofactors. We report here the cloning of a novel AR coactivator ARA55 using a yeast two-hybrid system. ARA55 consists of 444 amino acids with the predicted molecular mass of 55 kDa and its sequence shows very high homology to mouse hic5, a TGF-beta1-inducible gene. Yeast and mammalian two-hybrid systems and co-immunoprecipitation assays all prove ARA55 can bind to AR in a ligand-dependent manner. Transient transfection assay in prostate cancer DU145 cells further demonstrates that ARA55 can enhance AR transcriptional activity in the presence of 1 nM dihydrotestosterone or its antagonists such as 100 nM 17beta-estradiol or 1 microM hydroxyflutamide. Our data also suggest the C-terminal half of ARA55, which includes three LIM motifs, is sufficient to interact with AR. Northern blot and polymerase chain reaction quantitation showed ARA55 can be expressed differently in normal prostate and prostate tumor cells. Together, our data suggests that ARA55 may play very important roles in the progression of prostate cancer by the modulation of AR transactivation.

Amino Acid Sequence↗

PubMed1999

Alpha4 protein as a common regulator of type 2A-related serine/threonine protein phosphatases.

The catalytic activity of the C subunit of serine/threonine phosphatase 2A is regulated by the association with A (PR65) and B subunits. It has been reported that the alpha4 protein, a yeast homolog of the Tap42 protein, binds the C subunit of serine/threonine phosphatase 2A and protein phosphatase 2A-related protein phosphatases such as protein phosphatase 4 and protein phosphatase 6. In the present study, we showed that alpha4 binds these three phosphatases and the association of alpha4 reduces the activities of these phosphatases in vitro. In contrast, PR65 binds to the C subunit of serine/threonine phosphatase 2A but not to protein phosphatase 4 and protein phosphatase 6. These results suggest that the alpha4 protein is a common regulator of the C subunit of serine/threonine phosphatase 2A and protein phosphatase 2A-related protein phosphatases.

Adaptor Proteins, Signal Transducing↗

PubMed1999

A new member of the alpha4-related molecule (alpha4-b) that binds to the protein phosphatase 2A is expressed selectively in the brain and testis.

A murine alpha4, identified in lymphocytes, binds to protein phosphatase 2A (PP2A). We found another murine alpha4-related gene (named alpha4-b) expressed selectively in the brain and testis. The alpha4-b transcript is expressed in the brain and testis, but is not detected in the spleen, thymus, bone marrow, liver, kidney, lung, heart or muscle. In-situ RNA hybridization analysis suggested that alpha4-b is expressed in most neuronal cells in the brain, but it is not expressed in the glial cells. The alpha4-b cDNA encodes a putative protein that is highly homologous (66% identity in amino-acid sequence) to the alpha4 molecule. The alpha4-b protein associates with the catalytic subunit of PP2A (PP2Ac), suggesting that the alpha4-b protein is involved in the regulation of phosphatase activity in neuronal cells.

Adaptor Proteins, Signal Transducing↗

PubMed1999

Induction of TR4 orphan receptor by retinoic acid in human HaCaT keratinocytes.

Human TR4 orphan receptor (TR4) can modulate the transcriptional activity of the reporter gene containing an AGGTCA direct repeat-hormone response element. Here we studied the potential role of TR4 in human HaCaT keratinocytes. Using a chloramphenicol acetyl-transferase reporter gene assay, it was shown that TR4 can suppress retinoic acid-induced transactivation by 47.3% in human HaCaT keratinocytes. Electrophoretic mobility shift assay indicated that this suppression may be due to TR4 binding with higher affinity to the retinoic acid response element than retinoid receptors. Western blot analysis further suggested that retinoic acid can increase the expression of TR4 protein in human HaCaT keratinocytes, indicating that TR4 acts as a negative feedback modulator for retinoic acid action. Interestingly, TR4 expression is increased in normal human keratinocytes when substituting a low calcium medium with a high calcium medium. Together, our data suggested, for the first time, that an orphan receptor, such as TR4, may play an important part in retinoid-mediated signaling pathways in human keratinocytes, providing a new insight into keratinocyte biology.

Calcium↗

PubMed1999

Roles of testosterone in the growth of keratinocytes through bald frontal dermal papilla cells.

A coculture of dermal papilla cells (DPCs) from the bald frontal scalp of stumptailed macaques with keratinocytes derived from human neonatal foreskin revealed that testosterone inhibited keratinocyte proliferation, and that the antiandrogen RU58841 abolished this response. This testosterone-induced keratinocyte growth inhibition was not observed when either type of cells was cultured alone. We also examined conditioned media from the coculture system and demonstrated the identical testosterone-induced growth inhibition on keratinocytes, and this inhibitory effect was conditioned media concentration-dependent. These results suggested that the testosterone-mediated suppression on keratinocyte proliferation might proceed through some diffusible growth mediators in conditioned media. Differential display reverse transcriptase polymerase chain reaction allowed us to isolate several genes from frontal DPCs that can be either suppressed or induced by testosterone. Supervillin, a membrane-associated, F-actin-binding protein, was identified as one of the testosterone downregulated genes in frontal DPCs. Further characterization of these testosterone-target genes may reveal the mechanism by which testosterone inhibits the growth of follicular cells in androgenetic alopecia.

Alopecia↗

PubMed1998

Regulation of protein phosphatase 2A catalytic activity by alpha4 protein and its yeast homolog Tap42.

Recent studies have revealed that the alpha4 protein, a mammalian homolog of yeast Tap42, is associated with the protein phosphatase 2A catalytic subunit (PP2A-C), however, effects of the association of alpha4 with PP2A-C on its phosphatase activity have not been examined, especially using physiologically relevant substrates in the signaling pathway of mTOR (the mammalian target of rapamycin) protein. Here, we report how this association affects the enzymatic activity of PP2A-C using the recombinant eIF-4E binding protein (4E-BP1) phosphorylated by immunoprecipitated mTOR as a substrate. PP2A-C dephosphorylated 4E-BP1 in vitro. The association of alpha4 and Tap42 with PP2A-C inhibited the phosphatase activity toward 4E-BP1. Rapamycin treatment, however, neither induced restoration of the phosphatase activity of PP2A-C nor caused dissociation of alpha4 and Tap42 from PP2A-C. Our study is the first report to reveal a potential regulatory role of alpha4 and Tap42 to inibit the phosphatase activity of PP2A-C toward the physiologically relevant substrate in the mTOR signaling.

Adaptor Proteins, Signal Transducing↗