Circulating microRNAs reveal egg-brain crosstalk and a brain-predominant microRNA linked to the onset of the next reproductive cycle in iteroparous salmonids
Abstract
BACKGROUND: Mechanisms regulating the transition between two consecutive reproductive cycles are complex and remain poorly understood, mostly because they involve a dialog between the ovary and the central nervous system that is difficult to disentangle. RESULTS: In rainbow trout (Oncorhynchus mykiss), an iteroparous species spawning every year, removal of the eggs from the body cavity was used as a switch to trigger the onset of the next reproductive cycle. Changes in circulating miRNAs (c-miRNAs) levels in blood plasma and ovarian fluid were then monitored over time. Upon removal of the eggs from the body cavity, we observed the dramatic downregulation of the blood plasma levels of a single c-miRNA (miR-139-5p) that is predominantly expressed in the brain. In contrast, very distinct c-miRNAs profiles were observed in blood plasma when eggs are retained in the body cavity. Among plasma c-miRNAs showing dynamic changes with egg retention, miR-135c is strongly expressed in the brain and pituitary, while miR-457a is predominant in the post-ovulatory ovary. In addition, egg retention in the body cavity triggers a dramatic drop in ovarian fluid levels of miR-202-5p, a miRNA known to regulate egg production in fish. CONCLUSIONS: Our observations reveal that the transition between two successive reproductive cycles involves a crosstalk between the eggs and the central system and that a single miRNA, miR-139, predominantly expressed in the brain, is associated with the onset of the next reproductive cycle. We identified possible miR-139-5p functional targets in rainbow trout and other iteroparous species that have been lost in semelparous salmonids. Our results offer new research perspectives to better understand the mechanisms triggering the next reproductive cycle in iteroparous fish species, including post-transcriptional regulations by miR-139 in the brain.
Related
- Novel biallelic PATL2 variants causing predominant germinal vesicle arrest and recurrent ART failure: expanded mutational spectrum and evidence-based reproductive counseling guidance
- Very low-calorie diet reduces hepatic steatosis and remodels circulating metabolite-microRNAs networks in metabolic dysfunction-associated steatotic liver disease: A pilot study
- Association of Circulating microRNAs in Plasma with Coronary Collateral Circulation in Patients with Chronic Total Occlusion
- Circulating MicroRNAs Reflect Systemic Inflammation and Metabolic Dysfunction in Oesophageal Squamous Cell Carcinoma-Associated Cachexia.
- Circulating microRNAs Capture Inflammatory and Muscle Wasting Phenotypes in Patients with Gastrointestinal Cancer
BibTeX
@article{abreu2026circulating,
title = {{Circulating microRNAs reveal egg-brain crosstalk and a brain-predominant microRNA linked to the onset of the next reproductive cycle in iteroparous salmonids}},
author = {Mariana Roza de Abreu and Emilie Cardona and Camille Lagarde and Leo Milhade and Goro Yoshizaki and Violette Thermes and Julien Bobe},
journal = {BMC Biology},
year = {2026},
month = may,
doi = {10.1186/s12915-026-02643-2},
url = {https://hal.inrae.fr/hal-05773071v1},
note = {CC BY-NC-ND},
}
RIS
TY - JOUR
TI - Circulating microRNAs reveal egg-brain crosstalk and a brain-predominant microRNA linked to the onset of the next reproductive cycle in iteroparous salmonids
AU - Mariana Roza de Abreu
AU - Emilie Cardona
AU - Camille Lagarde
AU - Leo Milhade
AU - Goro Yoshizaki
AU - Violette Thermes
AU - Julien Bobe
PY - 2026
DA - 2026/05/21
JO - BMC Biology
DO - 10.1186/s12915-026-02643-2
UR - https://hal.inrae.fr/hal-05773071v1
AB - BACKGROUND: Mechanisms regulating the transition between two consecutive reproductive cycles are complex and remain poorly understood, mostly because they involve a dialog between the ovary and the central nervous system that is difficult to disentangle. RESULTS: In rainbow trout (Oncorhynchus mykiss), an iteroparous species spawning every year, removal of the eggs from the body cavity was used as a switch to trigger the onset of the next reproductive cycle. Changes in circulating miRNAs (c-miRNAs) levels in blood plasma and ovarian fluid were then monitored over time. Upon removal of the eggs from the body cavity, we observed the dramatic downregulation of the blood plasma levels of a single c-miRNA (miR-139-5p) that is predominantly expressed in the brain. In contrast, very distinct c-miRNAs profiles were observed in blood plasma when eggs are retained in the body cavity. Among plasma c-miRNAs showing dynamic changes with egg retention, miR-135c is strongly expressed in the brain and pituitary, while miR-457a is predominant in the post-ovulatory ovary. In addition, egg retention in the body cavity triggers a dramatic drop in ovarian fluid levels of miR-202-5p, a miRNA known to regulate egg production in fish. CONCLUSIONS: Our observations reveal that the transition between two successive reproductive cycles involves a crosstalk between the eggs and the central system and that a single miRNA, miR-139, predominantly expressed in the brain, is associated with the onset of the next reproductive cycle. We identified possible miR-139-5p functional targets in rainbow trout and other iteroparous species that have been lost in semelparous salmonids. Our results offer new research perspectives to better understand the mechanisms triggering the next reproductive cycle in iteroparous fish species, including post-transcriptional regulations by miR-139 in the brain.
SN - 1741-7007
SN - 1741-7007
ER -