Progesterone antagonism of estrogen-induced cytodifferentiation in chick oviduct

Differential expression of secreted phosphoprotein 1 in response to estradiol-17β and in ovarian tumors in chickens

Secreted phosphoprotein 1 (SPP1), a highly phosphorylated protein containing a polyaspartic acid sequence and a conserved RGD motif, plays important roles in physiological processes such as inflammatory responses, calcification, organ development, immune cell function and carcinogenesis. Results of the present study indicate expression of SPP1 mRNA in various organs such as oviduct, small intestine and kidney from chickens, particularly in the glandular epithelium (GE) of the shell gland and, to a lesser extent, in luminal epithelium (LE) of the infundibulum and magnum, and GE of the isthmus of the oviduct. We determined that DES (diethylstilbestrol, a synthetic nonsteroidal estrogen) decreases SPP1 expression in the oviduct and that SPP1 mRNA and protein are significantly more abundant in GE of ovarian endometrioid carcinoma, but not the other cancerous and normal ovaries of hens. Further, microRNA-140 was discovered to influence SPP1 expression via its 3'-UTR which suggests that post-transcriptional regulation influences SPP1 expression in chickens. Collectively, results of this study indicate that SPP1 is novel in that its expression is down-regulated by estrogen in epithelial cells of the chicken oviduct and that it is up-regulated in chicken ovarian endometrioid tumor that could be used for monitoring effects of therapies for this disease in laying hens.

Tissue specific expression and estrogen regulation of SERPINB3 in the chicken oviduct

Serine protease inhibitors (SERPINs) comprise the largest superfamily of protease inhibitors and appear to be ubiquitously expressed in a variety of species. Of these, squamous cell carcinoma antigen 1 (SCCA1), also known as a SERPINB3, was first identified in squamous cell carcinoma tissue from the cervix of women. However, there is little known about the expression and hormonal regulation of SERPINB3 in chickens. Therefore, the avian SERPINB3 gene was compared with those of other species with respect to structure, phylogenetic evolution and tissue- and cell-specific expression in hens. Chicken SERPINB3 has moderate homology to mammalian SERPINB3 proteins (36-47%). Of particular note, SERPINB3 mRNA was most abundant in the chicken oviduct and cell-specific expression was in glandular (GE) and luminal (LE) epithelial cells of the oviduct of laying hens. Treatment of young chicks with DES (diethylstilbestrol, a synthetic nonsteroidal estrogen) induced SERPINB3 mRNA and protein in GE and LE, but not in other cell types of the oviduct. Western blot analyses determined that immunoreactive SERPINB3 protein was also increased by DES in LE and GE of the oviduct of chicks. Collectively, these results indicate that SERPINB3 is an estrogen-induced gene expressed only in LE and GE of the chicken oviduct and implicate SERPINB3 in regulation of oviduct development and egg formation.

Differential expression of alpha 2 macroglobulin in response to dietylstilbestrol and in ovarian carcinomas in chickens

BACKGROUND

Alpha 2 macroglobulin (A2M; also known as ovostatin), a homotetrameric protein with four disulfide-linked subunits, has the unique feature of inactivating/inhibiting most known proteases including serine-, threonine-, cysteine-, aspartic- and metalloproteases. In chickens, A2M has been identified and characterized biochemically, but little is known of its functional role(s) in the oviduct, hormonal regulation of expression or its expression in ovarian carcinomas in chickens. Therefore, we investigated estrogen regulation of A2M gene expression during development of the chicken oviduct, and its expression in normal and cancerous ovaries from chickens.

METHODS

To determine tissue-specific expression of A2M in chickens, we collected various organs from male and female chickens and performed RT-PCR analyses. To examine A2M gene expression in the oviduct of 1-week-old female chicks that received a subcutaneous implant of 15 mg DES in the abdominal region for 20 days, we performed RT-PCR, qPCR and in situ hybridization analyses using cDNAs from control- (n=5) and DES-treated oviducts (n=5), and then each segment of the oviduct from DES-treated chicks. To determine if A2M is a biomarker of ovarian cancer in hens, we collected cancerous (n=10) ovaries from a total of 136 chickens which had completely stopped egg-laying and performed RT-PCR and in situ hybridization analyses.

RESULTS

We found that A2M is most abundant in the chicken oviduct, specifically luminal (LE) and glandular epithelia (GE), but it was not detected in any other tissues of either sex. We then determined that DES (dietylstilbestrol, a synthetic nonsteroidal estrogen) increased A2M mRNA only in LE and GE of the oviduct of chicks. Further, expression of A2M was most abundant in GE of endometrioid adenocarcinoma of cancerous, but not normal ovaries of hens.

CONCLUSIONS

Collectively, results of the present study indicate that A2M is novel estrogen-stimulated gene expressed in LE and GE of the chicken oviduct and may be used for monitoring effects of therapies for ovarian cancer in laying hens.

[Dynamics of amino acid and protein metabolism in laying hens after the administration of 15N-labeled wheat protein. 10. 15N-labeling of crude protein and amino acids of the oviducts]

Over a period of 4 days 12 colostomized laying hens daily received 36 g coarse wheat meal containing 14.37 atom-% 15N excess (15N') together with a conventional ration. After the homogenisation of each oviduct N and 15N' were determined. After the precipitation with TCA the 15N' of the amino acids was analysed in both the precipitate and the supernatant. In addition, the free amino acids and the peptides were determined in the TCA soluble fraction. The atom-% 15N' in the total N and in the non-basic amino acid N showed a parallel decrease; it diminished from 1.75 atom-% 15N' to 0.64. Of the three basic amino acids, lysine shows the lowest labelling at all four measuring points. The quotas of non-basic amino acid 14N and 15N' in the total 14N and 15N' of the oviduct are the same and amount to 53%. In contrast to this, the quota of the 14N of the basic amino acids in the total 14N of the oviduct only amounts to 21.6% and that of 15N' only to 15.4%. The average atom-% 15N' of the free amino acids 12 h after the last 15N application is 1.54 and is considerably above that of the peptides with 1.15 atom-% 15N'. 36 h after the last 15N application the ascertained value of 1.25 is identical in both fractions. The labelling of the free amino acids decreases more quickly than that of the peptides the more time has passed after the last 15N application.

Rapid regulation of c-myc protooncogene expression by progesterone in the avian oviduct

The mRNA levels of genes known to be regulated by sex steroids are not altered until 1 hr or longer after steroid treatment, although the steroid receptor complexes are bound to nuclear acceptor sites within 5 min. In a search for early regulation of gene transcription, total chick oviduct RNA was isolated at various times after injection (i.p.) of progesterone and analyzed for c-myc expression. Levels of c-myc mRNA began to decrease in response to progesterone by 10 min after injection. The mRNA levels continued to decrease, reached a 70% reduction at 30 min, and returned to control values by 8 hr after steroid injection. Changes in alpha-tubulin mRNA levels were markedly less in these same RNA preparations. The effect was dependent on the dose of the steroid and was target-tissue specific. These changes occurred much more rapidly than changes in egg-white protein mRNA levels. Vehicle alone did not alter c-myc mRNA levels. Early regulated genes such as c-myc may represent the initial site of action of steroid receptors in the genome.

Immunofluorescence demonstration of avidin in the immature chick oviduct epithelium after progesterone

Immature chicks were used for the experiments 1-2 days after hatching. A group of chicks were injected with 5 mg of progesterone and sacrificed 1 or 24 hr later. An other group of chicks were injected daily for 9 days with 5 mg of diethylstilbestrol and thereafter with single injection of progesterone. Cryostat sections were incubated with rabbit anti-avidin serum and with fluorescein labelled antirabbit globulin for fluorescence histochemistry. In the control animals no epithelial cells of the oviduct were fluorescence positive independently whether or not the animals were pretreated with diethylstilbestrol. One hour after administration of progesterone epithelial cells showed occasionally a slight synthesis of avidin. 24 hours after the injection of progesterone most, however never all, of the epithelial cells showed avidin in the apical part of the cell. The fluorescence reaction was clearly more intense if the animals were estrogen-primed. Diethylstilbestrol caused a differentiation of oviductal glands which were, however, only occasionally avidin positive after progesterone. These results suggest that primitive oviductal cells can produce avidin without preceding differentiation whereas estrogen causes a differentiation of new line of cells which have regularly lost their capacity of avidin synthesis after progesterone administration.

Reprogramming in the absence of DNA synthesis in Galleria larval epidermis

Larval epidermal cells from a day-1 penultimate instar Galleria larva on implantation into day-5 last instar larva metamorphose and deposit a pupal cuticle at the same time as the host pupates. DNA synthesis in the implanted larval cell was monitored with 3-H-thymidine. Various regimens of 3-H-thymidine application were used and under no conditions did the larval cells incorporate label during the period from implantation to deposition of pupal cuticle. This suggests that a wax moth larval ectoderm cell can reprogram its genome to secrete a pupal cuticle without a precedent cell division.

A syndrome of multiple congenital anomalies associated with teratogenic exposure

A study of 19 patients with multiple congenital anomalies described by the acronym VACTERL (Vertebral, Anal, Cardiac, Tracheoesophageal, Renal, and Limb) revealed exposure at the vulnerable period of embryogenesis to a progestogen/estrogen compound or a progestogen alone in 13 patients. These hormones were taken as a "pregnancy test," and for a variety of other reasons. Comparison of VACTERL patients with paired and matched controls, one group with chromosomal anomalies (other than Down syndrome) and another group with functional murmurs, revealed a significant difference with respect to exposure to hormonal contraceptives. The multiple anomalies of skeletal, cardiovascular, and gastrointestinal structures recapitulate the systems involved in the thalidomide syndrome, but present a variation of the pattern. Until more definitive data are available it would be prudent to emphasize the need to verify the absence of pregnancy before initiation of oral contraception and to discontinue hormonal agents as tests for pregnancy.

Interaction of estrogen and progesterone in chick oviduct development. II. Effects of estrogen and progesterone on tubular gland cell function

The effects of estrogen and progesterone on the function of chick oviduct tubular gland cells have been studied. Such function, as measured by the increase in specific cell products such as lysozyme and ovalbumin, requires the continuous presence of estrogen or progesterone. Withdrawal of hormone results in a rapid cessation of function and an involution of the oviduct accompanied by rapid decreases in total weight, lysozyme, and RNA. During such involution, tubular gland cells per se persist, as evidenced by a lack of comparable decrease in total DNA content and by histological demonstration of tubular gland cells. When estrogen administration is reinstituted, preexisting tubular gland cells rapidly synthesize ovalbumin and lysozyme without requiring new DNA synthesis. Administration of progesterone also stimulates the function of such cells. Furthermore, the effects of estrogen and progesterone are synergistic on the synthesis of lysozyme and ovalbumin, whereas progesterone antagonizes the estrogen-evoked formation of tubular gland cells. It is suggested that such complex interactions of estrogen and progesterone on oviduct development and function result from differences in responsiveness of the various cell types present in the tissue.