Mullerian inhibiting substance: a gonadal hormone with multiple functions

Mullerian inhibiting substance (MIS) is the gonadal hormone that causes regression of the Mullerian ducts, the anlagen of the female internal reproductive structures, during male embryogenesis. MIS is a member of the large transforming growth factor-beta (TGF beta) multigene family of glycoproteins that are involved in the regulation of growth and differentiation. The proteins in this gene family are all produced as dimeric precursors and undergo posttranslational processing for activation, requiring cleavage and dissociation to release bioactive C-terminal fragments. Similarly, the 140 kilodalton (kDa) disulfide-linked homodimer of MIS is proteolytically cleaved to generate its active C-terminal fragments. The sexually dimorphic expression of MIS in Sertoli cells of the testis and granulosa cells of the ovary is critical for normal differentiation of the internal reproductive tract structures. A number of extra-Mullerian functions such as control of germ cell maturation and gonadal morphogenesis, induction of the abdominal phase of testicular descent, suppression of lung maturation, and growth inhibition of transformed cells have also been proposed for this growth-inhibitory hormone and will be discussed. This article will summarize the current understanding of the biology and multiple functions of MIS including its activation, regulation, and mechanism of action and discuss areas of interest in ongoing research

Müllerian inhibiting substance/anti-Müllerian hormone: A novel treatment for gynecologic tumors

Müllerian inhibiting substance (MIS), also called anti-Müllerian hormone (AMH), is a member of the transforming growth factor-β super-family of growth and differentiation response modifiers. It is produced in immature Sertoli cells in male embryos and binds to MIS/AMH receptors in primordial Müllerian ducts to cause regression of female reproductive structures that are the precursors to the fallopian tubes, the surface epithelium of the ovaries, the uterus, the cervix, and the upper third of the vagina. Because most gynecologic tumors originate from Müllerian duct-derived tissues, and since MIS/AMH causes regression of the Müllerian duct in male embryos, it is expected to inhibit the growth of gynecologic tumors. Purified recombinant human MIS/AMH causes growth inhibition of epithelial ovarian cancer cells and cell lines in vitro and in vitro via MIS receptor-mediated mechanism. Furthermore, several lines of evidence suggest that MIS/AMH inhibits proliferation in tissues and cell lines of other MIS/AMH receptor-expressing gynecologic tumors such as cervical, endometrial, breast, and in endometriosis as well. These findings indicate that bioactive MIS/AMH recombinant protein should be tested in patients against tumors expressing the MIS/AMH receptor complex, perhaps beginning with ovarian cancer because it has the worst prognosis. The molecular tools to identify MIS/AMH receptor expressing ovarian and other cancers are in place, thus, it is possible to select patients for treatment. An MIS/AMH ELISA exists to follow administered doses of MIS/AMH, as well. Clinical trials await the production of sufficient supplies of qualified recombinant human MIS/AMH for this purpose

Measurements of serum mullerian inhibiting substance in the evaluation of children with nonpalpable gonads

BACKGROUND: Mullerian inhibiting substance, produced constitutively by the prepubertal testes, promotes involution of the mullerian ducts during normal male sexual differentiation. In children with virilization and nonpalpable gonads, only those with testicular tissue should have detectable serum concentrations of mullerian inhibiting substance. METHODS: We measured serum mullerian inhibiting substance in 65 children with virilization at birth and nonpalpable gonads (age at diagnosis, 2 days to 11 years) and serum testosterone in 54 of them either after the administration of human chorionic gonadotropin or during the physiologic rise in testosterone that occurs in normal infants. RESULTS: The mean (+/-SD) serum mullerian inhibiting substance concentration in the 17 children with no testicular tissue was 0.7+/-0.5 ng per milliliter, as compared with 37.5+/-39.6 ng per milliliter in the 48 children with testes (P CONCLUSIONS: Measurements of serum mullerian inhibiting substance can be used to determine testicular status in prepubertal children with nonpalpable gonads, thus differentiating anorchia from undescended testes in boys with bilateral cryptorchidism and serving as a measure of testicular integrity in children with intersexual anomalies

AMH/MIS as a contraceptive that protects the ovarian reserve during chemotherapy

The ovarian reserve represents the stock of quiescent primordial follicles in the ovary which is gradually depleted during a woman\u27s reproductive lifespan, resulting in menopause. Mullerian inhibiting substance (MIS) (or anti-Mullerian hormone/AMH), which is produced by granulosa cells of growing follicles, has been proposed as a negative regulator of primordial follicle activation. Here we show that long-term parenteral administration of superphysiological doses of MIS, using either an adeno-associated virus serotype 9 (AAV9) gene therapy vector or recombinant protein, resulted in a complete arrest of folliculogenesis in mice. The ovaries of MIS-treated mice were smaller than those in controls and did not contain growing follicles but retained a normal ovarian reserve. When mice treated with AAV9/MIS were paired with male breeders, they exhibited complete and permanent contraception for their entire reproductive lifespan, disrupted vaginal cycling, and hypergonadotropic hypogonadism. However, when ovaries from AAV9-MIS-treated mice were transplanted orthotopically into normal recipient mice, or when treatment with the protein was discontinued, folliculogenesis resumed, suggesting reversibility. One of the important causes of primary ovarian insufficiency is chemotherapy-induced primordial follicle depletion, which has been proposed to be mediated in part by increased activation. To test the hypothesis that MIS could prevent chemotherapy-induced overactivation, mice were given carboplatin, doxorubicin, or cyclophosphamide and were cotreated with AAV9-MIS, recombinant MIS protein, or vehicle controls. We found significantly more primordial follicles in MIS-treated animals than in controls. Thus treatment with MIS may provide a method of contraception with the unique characteristic of blocking primordial follicle activation that could be exploited to prevent the primary ovarian insufficiency often associated with chemotherapy

Mullerian inhibiting substance preferentially inhibits stem/progenitors in human ovarian cancer cell lines compared with chemotherapeutics

Cancer stem cells are proposed to be tumor-initiating cells capable of tumorigenesis, recurrence, metastasis, and drug resistance, and, like somatic stem cells, are thought to be capable of unlimited self-renewal and, when stimulated, proliferation and differentiation. Here we select cells by expression of a panel of markers to enrich for a population with stem cell-like characteristics. A panel of eight was initially selected from 95 human cell surface antigens as each was shared among human ovarian primary cancers, ovarian cancer cell lines, and normal fimbria. A total of 150 combinations of markers were reduced to a panel of three—CD44, CD24, and Epcam—which selected, in three ovarian cancer cell lines, those cells which best formed colonies. Cells expressing CD44, CD24, and Epcam exhibited stem cell characteristics of shorter tumor-free intervals in vivo after limiting dilution, and enhanced migration in invasion assays in vitro. Also, doxorubicin, cisplatin, and paclitaxel increased this enriched population which, conversely, was significantly inhibited by Müllerian inhibiting substance (MIS) or the MIS mimetic SP600125. These findings demonstrate that flow cytometry can be used to detect a population which shows differential drug sensitivity, and imply that treatment of patients can be individualized to target both stem/progenitor cell enriched and nonenriched subpopulations. The findings also suggest that this population, amenable to isolation by flow cytometry, can be used to screen for novel treatment paradigms, including biologic agents such as MIS, which will improve outcomes for patients with ovarian cancer

PLS3 Missense Variants Affecting the Actin-Binding Domains Cause X-Linked Congenital Diaphragmatic Hernia and Body-Wall Defects

Congenital diaphragmatic hernia (CDH) is a relatively common and genetically heterogeneous structural birth defect associated with high mortality and morbidity. We describe eight unrelated families with an X-linked condition characterized by diaphragm defects, variable anterior body-wall anomalies, and/or facial dysmorphism. Using linkage analysis and exome or genome sequencing, we found that missense variants in plastin 3 (PLS3), a gene encoding an actin bundling protein, co-segregate with disease in all families. Loss-of-function variants in PLS3 have been previously associated with X-linked osteoporosis (MIM: 300910), so we used in silico protein modeling and a mouse model to address these seemingly disparate clinical phenotypes. The missense variants in individuals with CDH are located within the actin-binding domains of the protein but are not predicted to affect protein structure, whereas the variants in individuals with osteoporosis are predicted to result in loss of function. A mouse knockin model of a variant identified in one of the CDH-affected families, c.1497G\u3eC (p.Trp499Cys), shows partial perinatal lethality and recapitulates the key findings of the human phenotype, including diaphragm and abdominal-wall defects. Both the mouse model and one adult human male with a CDH-associated PLS3 variant were observed to have increased rather than decreased bone mineral density. Together, these clinical and functional data in humans and mice reveal that specific missense variants affecting the actin-binding domains of PLS3 might have a gain-of-function effect and cause a Mendelian congenital disorder

Type IV collagen drives alveolar epithelial-endothelial association and the morphogenetic movements of septation

Background: Type IV collagen is the main component of the basement membrane that gives strength to the blood-gas barrier (BGB). In mammals, the formation of a mature BGB occurs primarily after birth during alveologenesis and requires the formation of septa from the walls of the saccule. In contrast, in avians, the formation of the BGB occurs rapidly and prior to hatching. Mutation in basement membrane components results in an abnormal alveolar phenotype; however, the specific role of type IV collagen in regulating alveologenesis remains unknown. Results: We have performed a microarray expression analysis in late chick lung development and found that COL4A1 and COL4A2 were among the most significantly upregulated genes during the formation of the avian BGB. Using mouse models, we discovered that mutations in murine Col4a1 and Col4a2 genes affected the balance between lung epithelial progenitors and differentiated cells. Mutations in Col4a1 derived from the vascular component were sufficient to cause defects in vascular development and the BGB. We also show that Col4a1 and Col4a2 mutants displayed disrupted myofibroblast proliferation, differentiation and migration. Lastly, we revealed that addition of type IV collagen protein induced myofibroblast proliferation and migration in monolayer culture and increased the formation of mesenchymal-epithelial septal-like structures in co-culture. Conclusions: Our study showed that type IV collagen and, therefore the basement membrane, play fundamental roles in coordinating alveolar morphogenesis. In addition to its role in the formation of epithelium and vasculature, type IV collagen appears to be key for alveolar myofibroblast development by inducing their proliferation, differentiation and migration throughout the developing septum

De novo variants in congenital diaphragmatic hernia identify MYRF as a new syndrome and reveal genetic overlaps with other developmental disorders

Congenital diaphragmatic hernia (CDH) is a severe birth defect that is often accompanied by other congenital anomalies. Previous exome sequencing studies for CDH have supported a role of de novo damaging variants but did not identify any recurrently mutated genes. To investigate further the genetics of CDH, we analyzed de novo coding variants in 362 proband-parent trios including 271 new trios reported in this study. We identified four unrelated individuals with damaging de novo variants in MYRF (P = 5.3x10-8), including one likely gene-disrupting (LGD) and three deleterious missense (D-mis) variants. Eight additional individuals with de novo LGD or missense variants were identified from our other genetic studies or from the literature. Common phenotypes of MYRF de novo variant carriers include CDH, congenital heart disease and genitourinary abnormalities, suggesting that it represents a novel syndrome. MYRF is a membrane associated transcriptional factor highly expressed in developing diaphragm and is depleted of LGD variants in the general population. All de novo missense variants aggregated in two functional protein domains. Analyzing the transcriptome of patient-derived diaphragm fibroblast cells suggest that disease associated variants abolish the transcription factor activity. Furthermore, we showed that the remaining genes with damaging variants in CDH significantly overlap with genes implicated in other developmental disorders. Gene expression patterns and patient phenotypes support pleiotropic effects of damaging variants in these genes on CDH and other developmental disorders. Finally, functional enrichment analysis implicates the disruption of regulation of gene expression, kinase activities, intra-cellular signaling, and cytoskeleton organization as pathogenic mechanisms in CDH

Effects of Anacetrapib in Patients with Atherosclerotic Vascular Disease

BACKGROUND: Patients with atherosclerotic vascular disease remain at high risk for cardiovascular events despite effective statin-based treatment of low-density lipoprotein (LDL) cholesterol levels. The inhibition of cholesteryl ester transfer protein (CETP) by anacetrapib reduces LDL cholesterol levels and increases high-density lipoprotein (HDL) cholesterol levels. However, trials of other CETP inhibitors have shown neutral or adverse effects on cardiovascular outcomes. METHODS: We conducted a randomized, double-blind, placebo-controlled trial involving 30,449 adults with atherosclerotic vascular disease who were receiving intensive atorvastatin therapy and who had a mean LDL cholesterol level of 61 mg per deciliter (1.58 mmol per liter), a mean non-HDL cholesterol level of 92 mg per deciliter (2.38 mmol per liter), and a mean HDL cholesterol level of 40 mg per deciliter (1.03 mmol per liter). The patients were assigned to receive either 100 mg of anacetrapib once daily (15,225 patients) or matching placebo (15,224 patients). The primary outcome was the first major coronary event, a composite of coronary death, myocardial infarction, or coronary revascularization. RESULTS: During the median follow-up period of 4.1 years, the primary outcome occurred in significantly fewer patients in the anacetrapib group than in the placebo group (1640 of 15,225 patients [10.8%] vs. 1803 of 15,224 patients [11.8%]; rate ratio, 0.91; 95% confidence interval, 0.85 to 0.97; P=0.004). The relative difference in risk was similar across multiple prespecified subgroups. At the trial midpoint, the mean level of HDL cholesterol was higher by 43 mg per deciliter (1.12 mmol per liter) in the anacetrapib group than in the placebo group (a relative difference of 104%), and the mean level of non-HDL cholesterol was lower by 17 mg per deciliter (0.44 mmol per liter), a relative difference of -18%. There were no significant between-group differences in the risk of death, cancer, or other serious adverse events. CONCLUSIONS: Among patients with atherosclerotic vascular disease who were receiving intensive statin therapy, the use of anacetrapib resulted in a lower incidence of major coronary events than the use of placebo. (Funded by Merck and others; Current Controlled Trials number, ISRCTN48678192 ; ClinicalTrials.gov number, NCT01252953 ; and EudraCT number, 2010-023467-18 .)

Women in applied behavior analysis

The status of women in applied behavior analysis was examined by comparing the participation of women in the Journal of Applied Behavior Analysis ( JABA ) to their participation in three similar journals. For all journals, the percentage of articles with at least one female author, the percentage of authors who are female, and the percentage of articles with a female first author increased from 1978 to 1997. Participation by women in JABA was equal to or greater than participation by women in the comparison journals. However, women appeared as authors on papers in special sections of Behavior Modification substantially more often when the editor was female than when the editor was male. In addition, female membership on the editorial boards of JABA, Behavior Modification , and Behaviour Research and Therapy failed to increase from 1978 to 1997. We conclude that a “glass ceiling” reduces the participation of women at the highest levels of applied behavior analysis and related fields