Immune-Specific Expression and Estrogenic Regulation of the Four Estrogen Receptor Isoforms in Female Rainbow Trout (Oncorhynchus mykiss).

Casanova, Ayako; Wernicke von Siebenthal, Elena; Kropf, Christian; Oldenberg, Elisabeth; Segner, Helmut (2018). Immune-Specific Expression and Estrogenic Regulation of the Four Estrogen Receptor Isoforms in Female Rainbow Trout (Oncorhynchus mykiss). International journal of molecular sciences, 19(4) Molecular Diversity Preservation International MDPI 10.3390/ijms19040932

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Genomic actions of estrogens in vertebrates are exerted via two intracellular estrogen receptor (ER) subtypes, ERα and ERβ, which show cell- and tissue-specific expression profiles. Mammalian immune cells express ERs and are responsive to estrogens. More recently, evidence became available that ERs are also present in the immune organs and cells of teleost fish, suggesting that the immunomodulatory function of estrogens has been conserved throughout vertebrate evolution. For a better understanding of the sensitivity and the responsiveness of the fish immune system to estrogens, more insight is needed on the abundance of ERs in the fish immune system, the cellular ratios of the ER subtypes, and their autoregulation by estrogens. Consequently, the aims of the present study were (i) to determine the absolute mRNA copy numbers of the four isoforms in the immune organs and cells of rainbow trout, , and to compare them to the hepatic numbers; (ii) to analyse the mRNA isoform ratios in the immune system; and, (iii) finally, to examine the alterations of immune mRNA expression levels in sexually immature trout exposed to 17β-estradiol (E2), as well as the alterations of immune mRNA expression levels in sexually mature trout during the reproductive cycle. All four ER isoforms were present in immune organs-head kidney, spleen-and immune cells from head kidney and blood of rainbow trout, but their mRNA levels were substantially lower than in the liver. The ER isoform ratios were tissue- and cell-specific, both within the immune system, but also between the immune system and the liver. Short-term administration of E2 to juvenile female trout altered the mRNA levels in the liver, but the ERs of the immune organs and cells were not responsive. Changes of gene transcript numbers in immune organs and cells occurred during the reproductive cycle of mature female trout, but the changes in the immune ER profiles differed from those in the liver and gonads. The correlation between gene transcript numbers and serum E2 concentrations was only moderate to low. In conclusion, the low mRNA numbers of nuclear ER in the trout immune system, together with their limited estrogen-responsiveness, suggest that the known estrogen actions on trout immunity may be not primarily mediated through genomic actions, but may involve other mechanisms, such as non-genomic pathways or indirect effects.

Item Type:

Journal Article (Original Article)

Division/Institute:

05 Veterinary Medicine > Research Foci > Host-Pathogen Interaction
05 Veterinary Medicine > Department of Infectious Diseases and Pathobiology (DIP)
05 Veterinary Medicine > Department of Infectious Diseases and Pathobiology (DIP) > Center for Fish and Wildlife Health (FIWI)

UniBE Contributor:

Casanova, Ayako; Wernicke von Siebenthal, Elena; Kropf, Christian; Oldenberg, Elisabeth and Segner, Helmut

Subjects:

500 Science > 570 Life sciences; biology
600 Technology > 630 Agriculture

ISSN:

1661-6596

Publisher:

Molecular Diversity Preservation International MDPI

Language:

English

Submitter:

Achim Braun Parham

Date Deposited:

29 May 2019 14:01

Last Modified:

29 May 2019 14:10

Publisher DOI:

10.3390/ijms19040932

PubMed ID:

29561790

Uncontrolled Keywords:

estrogen receptor immune system isoforms rainbow trout reproductive cycle

BORIS DOI:

10.7892/boris.129624

URI:

https://boris.unibe.ch/id/eprint/129624

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