Certain paracrine factors implicated in germ stem cell fate could also exhibit additional endocrine functions throughout the reproductive cycle of rainbow trout (Oncorhynchus mykiss) - Archive ouverte HAL
Communication Dans Un Congrès Année : 2024

Certain paracrine factors implicated in germ stem cell fate could also exhibit additional endocrine functions throughout the reproductive cycle of rainbow trout (Oncorhynchus mykiss)

Résumé

As in mammals, spermatogenesis in fish requires seasonal or continuous renewal and differentiation of a limited stock of germ stem cells (GSCs). GSCs are not autonomous cells and their cell fate is regulated by paracrine factors which are massively expressed and secreted from surrounding somatic testicular cells under the endocrine control of gonadotropins and/or sexual steroids. It is well admitted that the synthesis and/or release of the gonadotropins and sexual steroids in the blood are restricted through negative or positive feedback loops involving gonadal factors. The present study was originally aimed at identifying such gonadal factors that could be released into the bloodstream throughout the reproductive cycle of rainbow trout and act as extra-gonadal endocrine mediators. Blood plasma were collected in 2020 and 2021 from male and female rainbow trout (Oncorhynchus mykiss) at different ages and stages of sexual maturation (n=6 in each group). Immature and maturing fish were euthanized at 9 and 15 months of age, respectively. Sexually mature fish were euthanized at 20 months of age. Plasma proteins were separated on polyacrylamide gels and digested with a trypsin/ lys-C mix (Promega). Peptides were injected in a timsTOF Pro mass spectrometer (Bruker Daltonik) and detected using a high throughput proteomic approach based on Parallel Accumulation-Serial Fragmentation and Data Independent Acquisition (DIA-PASEF). Data were analysed using the spectronaut v16.0 software (Biognosys) with a library-based approach. The proteomic analysis of blood plasma samples allowed the identification of 42.288 peptides segregating in 4096 “protein groups”. 3534 “protein groups” were related to single copy gene or closely related genes recently duplicated (known as ohnologous genes). High throughput RNA sequencing, conducted on 8 different tissues collected from immature or sexually mature fish allowed us to detect transcripts encoding for 4011 out of 4096 “protein groups”. In addition, we observed that 84 “protein groups” encoding for proteins harboring a predicted secretion signal were related to transcripts specifically expressed in the gonads. This group of proteins from probable gonadal origin included different subunits of B inhibins that are known to be the only functional isoforms involved in the negative feedback of Fsh secretion in vertebrates. We also identified proteins related to hormone binding proteins (Igf binding protein, sex hormone binding globulin), protease inhibitors, and proteins involved in post-translational modifications. Interestingly, we identified the Amh and Gsdf proteins in the blood plasma with higher relative plasma levels in immature males. The relative plasma levels of the Amh protein decreased in mature males as previously observed in rainbow trout testes. The Gsdf plasma levels remained stable in males while a four-fold increase occurred during female sexual maturation. Both proteins have been previously involved in the paracrine regulation of GSC cell fate but our study suggests that these gonadal factors belonging to the TGF beta superfamily could also act as endocrine mediators of extra-gonadal tissue function. The biological relevance of this assumption will be discussed in light of existing knowledge gained from other vertebrate species. The project received funding from the European Maritime, Fisheries and Aquaculture Fund (project SexTiming: grant PFEA470018FA1000017).
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Dates et versions

hal-04690566 , version 1 (06-09-2024)

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  • HAL Id : hal-04690566 , version 1

Citer

Charline Danthu, Aurélien Brionne, Blandine Guével, Regis Lavigne, Emmanuelle Com, et al.. Certain paracrine factors implicated in germ stem cell fate could also exhibit additional endocrine functions throughout the reproductive cycle of rainbow trout (Oncorhynchus mykiss). 31. Conference of European Comparative Endocrinologists, Sep 2024, Ancona, Italy. ⟨hal-04690566⟩
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