The distribution of p29 protein in normal human skin

Paradoxical mitotic exit induced by a small molecule inhibitor of APC/CCdc20

The anaphase-promoting complex/cyclosome (APC/C) is a ubiquitin ligase that initiates anaphase and mitotic exit. APC/C is activated by Cdc20 and inhibited by the mitotic checkpoint complex (MCC), which delays mitotic exit when the spindle assembly checkpoint (SAC) is activated. We previously identified apcin as a small molecule ligand of Cdc20 that inhibits APC/C^Cdc20 and prolongs mitosis. Here we find that apcin paradoxically shortens mitosis when SAC activity is high. These opposing effects of apcin arise from targeting of a common binding site in Cdc20 required for both substrate ubiquitination and MCC-dependent APC/C inhibition. Furthermore, we found that apcin cooperates with p31^comet to relieve MCC-dependent inhibition of APC/C. Apcin therefore causes either net APC/C inhibition, prolonging mitosis when SAC activity is low, or net APC/C activation, shortening mitosis when SAC activity is high, demonstrating that a small molecule can produce opposing biological effects depending on regulatory context.

Psoriasis: female skin changes in various hormonal stages throughout life--puberty, pregnancy, and menopause

Psoriasis is one of the most prevalent immune mediated skin diseases worldwide. Despite the large prevalence in both men and women, the pathogenesis of this disease has not yet been fully clarified. Nowadays, it is believed that psoriasis is most likely a T helper Th1/Th17 induced inflammatory disease. Stressful life situations are known to cause flare-ups and psoriasis activity may be linked to stress from major life events. We know that stress greatly affects both the hormone and immune systems and that there are many different hormonal phases throughout a woman's lifetime. The severity of psoriasis may fluctuate or be influenced by each phase and this relationship can be seen as disease frequency seems to peak during puberty, postpartum, and menopause when hormone levels fall, while symptoms improve during pregnancy, a state when hormone levels are increased.

Estrogens and the skin

OBJECTIVE

A review of the medical literature concerning the effect of the menopause and its hormonal treatment on the skin.

METHODS

An extensive Medline and Pubmed internet search utilizing the key words: collagen, elastin, estrogen, hormone replacement therapy, skin and aging.

RESULTS

The literature review demonstrated a wide array of research ranging from basic science work to clinical implications of the effects of the menopause and its treatment on the skin.

CONCLUSION

Estrogen loss at menopause has a profound influence on skin. Estrogen treatment in postmenopausal women has been repeatedly shown to increase collagen content, dermal thickness and elasticity, and data on the effect of estrogen on skin water content are also promising. Further, physiologic studies on estrogen and wound healing suggest that hormone replacement therapy (HRT) may play a beneficial role in cutaneous injury repair. Results on the effect of HRT on other physiologic characteristics of skin, such as elastin content, sebaceous secretions, wrinkling and blood flow, are discordant. Given the responsiveness of skin to estrogen, the effects of HRT on aging skin require further examination, and careful molecular studies will likely clarify estrogen's effects at the cellular level.

Medroxyprogesterone acetate antagonizes the effects of estrogen treatment on social and sexual behavior in female macaques

Medroxyprogesterone acetate (MPA) commonly is used in contraception and hormone replacement therapy. However, little is known about its effects within the central nervous system. Using ovariectomized pigtail macaques (Macaca nemestrina), we evaluated the potential for MPA to antagonize estradiol (E2) effects on female sociosexual behavior. Subjects (n = 6) were treated sequentially with placebo, E2 alone, E2 + progesterone (P4), and E2 + MPA. The order of treatments was balanced among subjects, and equimolar quantities of P4 and MPA were administered. During each treatment period, female sexual initiation rates, anxiety-related behavior, and aggression were recorded. Treatment with E2 alone induced a substantial rise in female sexual initiation rates. Although concurrent P4 treatment failed to significantly inhibit sexual behavior, MPA treatment markedly antagonized E2's effects. Neither the E2-only nor the E2 + P4 treatment had an impact on aggression rates, but the E2 + MPA treatment induced a significant rise in this behavior. Both MPA and P4 counteracted the effect of E2 on measures of anxiety. These findings suggest that MPA antagonizes certain behavioral effects of E2 that may be beneficial to women, and that it does so more profoundly or in ways that endogenous P4 does not. The marked increase in aggression seen during MPA treatment suggests that production of negative affect may be a particularly serious side effect of MPA.

Oestrogens and the skin

Oestrogen loss at the menopause has a profound influence on skin. Oestrogen treatment in post-menopausal women has repeatedly been shown to increase collagen content, dermal thickness and elasticity. Data on the effect of oestrogen on skin water content are also promising. Further, physiological studies on oestrogen and wound healing suggest that hormone replacement therapy (HRT) may play a beneficial role in cutaneous injury repair. Results of the effect of HRT on other physiological characteristics of skin, such as elastin content, sebaceous secretions, wrinkling and blood flow, are discordant. Given the responsiveness of skin to oestrogen, the effects of HRT on ageing skin require further examination and careful molecular studies will probably clarify oestrogen's effects at the cellular level.

Skin aging and menopause : implications for treatment

The skin is one of the largest organs of the body, which is significantly affected by the aging process and menopause. The significant changes sustained by the skin during the menopause are due to the effect sustained on the skin's individual components. The estrogen receptor has been detected on the cellular components of the skin. Accordingly, dermal cellular metabolism is influenced by the hypoestrogenoemic state of menopause leading to changes in the collagen content, alterations in the concentration of glycoaminoglycans and most importantly the water content. Consequently changes in these basic components leads to an alteration in function compatible with skin aging. Changes in the skin collagen leads to diminished elasticity and skin strength. Collagen content may be measured by various methods such as direct skin biopsy, skin blister assessment for collagen markers and skin thickness measurement. All these variables indicate a reduction in collagen content following menopause. This may be reversed with the administration of estrogen given both topically and systemically.A reduction in hydrophilic glycoaminglycans leads to a direct reduction in water content, which influences the skin turgor. These effects on glycoaminoglycans, due to the hypoestrogenia, have been clearly shown in animal studies and appeared to be rapidly reversed with the application of estrogens. The sum total of these basic effects on the skin leads to wrinkles, the skin condition typifying skin aging.Structures resident in the skin are likewise influenced by menopause. Changes to the cutaneous vascular reactivity are noted following menopause. Capillary blood flow velocity decreases significantly in postmenopausal women. Postmenopausal flushing is due to profound vasodilatation in the dermal papillae. Hair growth is also influenced by the hormonal milieu and consequently hair loss has been associated with the beginning of menopause. Treatments administered for menopause, in particular hormone replacement therapy, appear to alter its effects on the basic components of the skin as well as the more complex structures residing in the skin, consequently retarding the skin aging process.

Menopause and the skin

Women live one-third of their lives in the post-menopausal state. Significant hormonal alterations occur at the time of menopause, leading to a range of physiological disorders affecting multiple organ systems in the body. The effects of menopause on the skin have been underresearched. Many skin changes occur at the time of menopause and the cutaneous effects of hormone replacement therapy are significant. Menopausal changes in hormones may alter the biomechanical properties of the skin and certain disorders are more common in menopausal women, such as lichen sclerosus, atrophic vulvovaginitis, flushing and dysaesthetic vulvodynia. Hair and oral changes may also be associated. As the average life expectancy increases, dermatologists need to be familiar with skin diseases affecting women in this age group.

Hormone replacement therapy and the skin

Estrogens have a profound influence on skin. The hypoestrogenism occurring after the menopause leads to measured deterioration in the skin. Estrogen receptors have been identified in the skin and the concentration of these receptors varies in the different parts of the body. Estrogen improves skin in more than one way, the collagen content and quality is improved, skin thickness is increased, while vascularisation is enhanced. The extracellular matrix responsible for the tone and appearance of the skin is also improved. It is not just the skin that shows an improvement with estrogen therapy but also skin appendages, such as hair. Estrogens have been shown to increase the hair follicle life cycle. Skin aging is not totally estrogen dependent because the ravages of age and the external environment play very important roles. The effects of estrogen on skin need further elucidation and with the emergence of newer techniques it is now possible to study more clearly the changes occurring at the cellular level. Estrogen replacement reverses the deleterious effect of estrogen deprivation on the skin, which is thus yet another organ that benefits from hormone replacement therapy.

Female sex hormone stimulates cultured human keratinocyte proliferation and its RNA- and protein-synthetic activities

The present study was carried out to assess the effect of female sex hormones, i.e., estrogen and progesterone, on human keratinocyte proliferation, and its RNA- and protein-synthetic activities in a culture system. The presence of receptors for estrogen and progesterone and their messenger ribonucleic acids (mRNAs) in the cultured cells was also investigated. Human keratinocytes were cultured in the experimental DMEM-Ham's F12 medium containing various concentrations of estrogen or progesterone, which was followed by determining cell yields and [3H]thymidine incorporation. The keratinocytes were also tested for RNA- and protein-synthetic activities by measuring [3H]uridine and [3H]leucine incorporation. Both estrogen and progesterone receptors were determined by the enzyme immunoassay method using monoclonal antibodies, and mRNA expression for these hormone receptors was detected by in situ hybridization. Cell yields and [3H]thymidine incorporation increased gradually until 3 x 10(-10) M of both estrogen and progesterone, decreased thereafter until 3 x 10(-7) M, and peaked at 3 x 10(-10) M. [3H]Uridine and [3H]leucine uptake followed almost the same pattern as the cell proliferation, peaking at 3 x 10(-10) M of both hormones. Small amounts of estrogen and progesterone receptors were present in the cultured cells, and their mRNAs were found to be present in the cell cytoplasm. These results clearly suggest that sex hormones play an important role in human keratinocyte proliferation, and its RNA- and protein-synthetic activities, at least in part, via their hormone receptors.

Presence of an oestradiol receptor-related protein in the skin: changes during the normal menstrual cycle

OBJECTIVE

To investigate the presence of an oestradiol receptor-related protein (P29) in skin and skin organelles, and to assess changes in its content during the normal menstrual cycle.

DESIGN

An observational study.

SETTING

King's College School of Medicine and Dentistry, London.

SUBJECTS

Twenty-one premenopausal women with regular menstrual cycles undergoing gynaecological surgery. They were allocated to proliferative or secretory phases of the menstrual cycle on the basis of menstrual dating and histological examination of an endometrial sample.

INTERVENTIONS

Small full thickness sections of skin (about 5 mm in depth) taken from the anterior abdominal wall at hysterectomy or laparoscopic sterilization.

MAIN OUTCOME MEASURES

The concentration of the oestradiol receptor-related protein in skin and its organelles was assessed semi-quantitatively, using a monoclonal antibody technique. The intensity of staining was compared between the proliferative and secretory phases of the cycle.

RESULTS

The receptor-related protein was consistently observed in epidermis, sebaceous glands, hair follicles and sweat ducts; there was no significant difference in its concentration between the proliferative and secretory phases of the menstrual cycle. The protein was not present in dermis and sweat ducts.

CONCLUSIONS

Epidermis and some skin organelles contain an oestradiol receptor-related protein and must be considered as oestrogen target tissues. However, the content of this protein does not appear to change significantly during the normal menstrual cycle.

Expression of estrogen receptors, progesterone receptors, and an estrogen receptor-associated protein in the human cervix during the menstrual cycle and menopause

Estrogen receptors (ERs), progesterone receptors (PRs), and P29, an ER-associated protein, were studied immunohistochemically in human cervix with use of specific monoclonal antibodies. In ectocervical epithelium, homogeneous staining was found for P29 throughout the menstrual cycle and after menopause. Weak or moderate staining was found for ER in the basal and, occasionally, the parabasal layers of ectocervix during the proliferative phase. In contrast, staining decreased in secretory phase and postmenopausal epithelia. Staining was negative for PR in all the exocervical epithelia. Heterogeneous staining, more pronounced for P29, was found for the three antigens of the study in endocervical epithelium. Staining did not change with the hormonal status of patients, except for ER, where staining decreased during the secretory phase. Stromal cells were negative or weakly positive, whereas muscular fibers were positive. This study suggests that the capacity of response of the steroid apparatus of cervical cells to fluctuations of circulating estrogens and progestins is limited compared with some of the cell functions, such as mucus secretion, or with other target tissues, such as endometrium. Additionally, the differences found in the pattern of expression of the three antigens studied suggest that the steroid-dependent growth and differentiation in ectocervix is regulated differently to endocervix.

Expression of an estrogen receptor-associated protein (p29) in epithelial tumors of the skin

p29 is a cytoplasmic serine phosphoprotein of 29 kD MW, closely linked to estrogen receptors. In this work we studied the expression of p29 protein in normal human skin and a group of cutaneous benign and malignant tumors by using a monoclonal antibody (ERD5) that specifically recognizes p29. In normal skin, p29 reactivity was observed in epidermal and some adnexal keratinocytes, as well as in smooth muscle cells of dermal arterioles and arrector pili muscles. p29 was also detected in most, but not all, epithelial tumors studied. The expression of p29 was generally stronger in the more differentiated (keratinized) normal and neoplastic keratinocytes; however, no correlation could be noted between immunochemical staining for p29 and either benignity of the lesion or sex of the patient considered. Whereas, in breast cancer, the expression of p29 is reported to correlate with endocrine response, the precise relationship between epithelial tumors of the skin and the action of estrogens remains to be elucidated.

Short-term effects of topical 17 beta-oestradiol on human post-menopausal skin

Early studies performed between 1946 and 1952 reported that cutaneously applied oestrogens had local effects in spite of probable systemic absorption. In order to test the validity of these observations the epidermal effects of topically applied 17 beta-oestradiol (E2) of 8 post-menopausal women were studied in a double-blind placebo-controlled cross-over study using non-invasive bioengineering techniques. E2 or placebo was applied twice daily for 45-50 days in a gel (at concentrations of 0.1 mg/g and 1.0 mg/g) and the results were compared. Changes in epidermal hydration (electrical capacitance and conductance) and mechanical properties were studied. We were unable to confirm the short-term local oestrogenic effects on post-menopausal human skin reported in the earlier studies. Thus, in spite of its high number of oestrogen receptors, the epidermis does not appear to be a target organ for oestrogens under clinical conditions.

Distribution of an estrogen receptor-related protein (P29) in normal skin and in cultured human keratinocytes

A monoclonal antibody, ERD5, which recognizes a 29Kd phosphoprotein associated with human estrogen receptor of myometrium was used to study the expression of this protein in normal skin and in cultured human keratinocytes. By indirect immunofluorescence, both in vivo and in vitro keratinocytes showed a variable cytoplasmic staining which increased with cell differentiation. SDS gel electrophoresis of soluble extracts of cultured keratinocytes and normal epidermis showed that P29 was a minor protein. Immunoblot analysis demonstrated that ERD5 strongly reacted only with a 29Kd polypeptide band without any cross-reactivity. These data suggest that keratinocytes might be estrogen sensitive like other cells in which P29 has already been located. The exact role of this protein in the keratinocyte differentiation process and its relationship with estrogen receptors remain to be elucidated.