Mutually exclusive cytoplasmic dynein regulation by NudE-Lis1 and dynactin

Cytoplasmic dynein is responsible for a wide range of cellular roles. How this single motor protein performs so many functions has remained a major outstanding question for many years. Part of the answer is thought to lie in the diversity of dynein regulators, but how the effects of these factors are coordinated in vivo remains unexplored. We previously found NudE to bind dynein through its light chain 8 (LC8) and intermediate chain (IC) subunits (1), the latter of which also mediates the dynein-dynactin interaction (2). We report here that NudE and dynactin bind to a common region within the IC, and compete for this site. We find LC8 to bind to a novel sequence within NudE, without detectably affecting the dynein-NudE interaction. We further find that commonly used dynein inhibitory reagents have broad effects on the interaction of dynein with its regulatory factors. Together these results reveal an unanticipated mechanism for preventing dual regulation of individual dynein molecules, and identify the IC as a nexus for regulatory interactions within the dynein complex.

Androgen receptor gene expression in the primate ovary: cellular localization, regulation, and functional correlations

Excess androgens are associated with a characteristic polyfollicular ovarian morphology; however, it is not known to what extent this problem is due to direct androgen action on follicular development vs. interference with gonadotropin release at the level of the pituitary or hypothalamus. To elucidate potential androgen effects on the ovary, we investigated the cellular localization of androgen receptor (AR) messenger ribonucleic acid (mRNA) in rhesus monkey using in situ hybridization. To investigate the regulation of ovarian AR gene expression, we compared the relative abundance of AR transcripts in monkeys during follicular and luteal phases of the menstrual cycle and in monkeys treated with testosterone. To assess potential functional consequences of AR expression in the primate ovary, we compared AR mRNA levels with indexes of follicular cell proliferation and apoptosis in serial sections from individual follicles. AR mRNA expression was most abundant in granulosa cells of healthy preantral and antral follicles in the primate ovary. Theca interna and stromal cells also expressed AR mRNA, but to a lesser degree than granulosa cells. No significant cycle stage effects were noted in AR mRNA levels; however, larger numbers of animals would be necessary to definitively establish a cycle stage effect. AR mRNA level was significantly increased in granulosa cells and was decreased in theca interna and stromal cells of testosterone-treated monkeys. Importantly, granulosa cell AR mRNA abundance was positively correlated with expression of the proliferation-specific antigen Ki-67 (r = 0.91; P < 0.001) and negatively correlated with granulosa cell apoptosis (r = -0.64; P < 0.001). In summary, these data show that primate ovary AR gene expression is most abundant in granulosa cells of healthy growing follicles, where its expression is up-regulated by testosterone. The positive correlation between granulosa AR gene expression and cell proliferation and negative correlation with programmed cell death suggests that androgens stimulate early primate follicle development.

Androgens stimulate early stages of follicular growth in the primate ovary

The concept that androgens are atretogenic, derived from murine ovary studies, is difficult to reconcile with the fact that hyperandrogenic women have more developing follicles than normal-cycling women. To evaluate androgen's effects on primate follicular growth and survival, normal-cycling rhesus monkeys were treated with placebo-, testosterone-(T), or dihydrotestosterone-sustained release implants, and ovaries were taken for histological analysis after 3-10 d of treatment. Growing preantral and small antral follicles up to 1 mm in diameter were significantly and progressively increased in number and thecal layer thickness in T-treated monkeys from 3-10 d. Granulosa and thecal cell proliferation, as determined by immunodetection of the Ki67 antigen, were significantly increased in these follicles. Preovulatory follicles (> 1 mm), however, were not increased in number in androgen-treated animals. Follicular atresia was not increased and there were actually significantly fewer apoptotic granulosa cells in the T-treated groups. Dihydrotestosterone treatment had identical effects, indicating that these growth-promoting actions are mediated by the androgen receptor. These findings show that, over the short term at least, androgens are not atretogenic and actually enhance follicular growth and survival in the primate. These new data provide a plausible explanation for the pathogenesis of "polycystic" ovaries in hyperandrogenism.

Chemotaxis of macrophages by a peritoneal fluid protein in women with endometriosis

OBJECTIVE

To expand on a preliminary study comparing the chemotactic potential of peritoneal fluid (PF) from women with and without endometriosis and to characterize this activity via immunosuppressants and a protease.

DESIGN

Case control study.

SETTING

University center.

PATIENT(S)

Fifty-nine women with endometriosis and 44 without, undergoing laparoscopy.

INTERVENTION(S)

Collection of PF, endometriotic, ovarian, and endometrial biopsies at laparoscopy.

MAIN OUTCOME MEASURE(S)

Chemotactic activity of PF was tested via an in vitro assay alone and in the presence of immunosuppressants cyclosporin A (CSA), FK506, rapamycin, and type XVII-b(S-V8) protease and in media incubated with endometriotic, ovarian, or endometrial biopsy specimens.

RESULT(S)

The PF from women with endometriosis had significantly greater chemotactic activity (cells per well, mean +/- SD) than without endometriosis (142 +/- 39 versus 48 +/- 17). Cyclosporin A significantly inhibited the chemotactic activity of the endometriotic PF; FK506 and rapamycin did not. Incubation of media with endometriotic tissue, but not ovarian or endometrial, for > or = 7 hours displayed chemotactic activity. Protease type XVII-b(S-V8) added to endometriotic PF inhibited this chemotactic activity.

CONCLUSION(S)

Peritoneal fluid from patients with endometriosis contains a protein chemotactic factor attracting inflammatory cells into the peritoneal cavity, possibly secreted by endometriotic implants. This chemotactic factor may be a member of the immunophilin family because of its inhibition profile.