Apoptosis and autophagy-related gene transcription during ovarian follicular atresia in European hake (Merluccius merluccius). (January 2023)

• Record Type: Journal Article
• Authors: Nzioka, Anthony; Valencia, Ainara; Atxaerandio-Landa, Aitor; Diaz de Cerio, Oihane; Hossain, Mohammad Amzad; Korta, Maria; Ortiz-Zarragoitia, Maren; Cancio, Ibon
• Is Part Of: Marine environmental research. Volume 183(2023)
• Publication Date: 2023-01
• Subjects: Apoptosis -- Autophagy -- Biomarker -- European hake -- Fisheries -- Follicular atresia -- mRNA -- Reproductive cycle; Marine pollution -- Environmental aspects -- Periodicals; Marine ecology -- Periodicals; Mer -- Pollution -- Aspect de l'environnement -- Périodiques; Écologie marine -- Périodiques; Electronic journals; 577.705
• DOI: 10.1016/j.marenvres.2022.105846
• Languages: English
• ISSNs: 0141-1136

Abstract

Abstract: Follicular atresia is an energy-saving oocyte resorption process that can allow the survival of female fish when environmental conditions are unfavourable and at the expense of fecundity. This study investigated the transcription levels of apoptosis and autophagy-related genes during atresia in the European hake that can show episodes of increased follicular atresia throughout the reproductive cycle. 169 female individuals were collected from the Bay of Biscay, and the ovaries were analysed using histological and molecular methods. Different levels of atresia were histologically detected in 73.7% of the ovaries analysed and the TUNEL assay identified apoptotic nuclei in follicles from both previtellogenic and vitellogenic stages. Transcripts of beclin-1 and ptenb were up-regulated in the ovaries containing atretic follicles, whereas p53, caspase-3, cathepsin D and dapk1 were up-regulated only in ovaries presenting vitellogenic atretic follicles. Our results indicate different implications of apoptotic vs autophagic processes leading to atresia during oocyte development, vitellogenesis being the moment of maximal apoptotic and autophagic activity in atretic hakes. The analysed genes could provide early warning biomarkers to identify follicular atresia in fish and evaluate fecundity in fish stocks. Highlights: A set of marker genes for the early estimation of ovarian follicular atresia in female European hakes is provided. Upregulation of beclin-1 and ptenb in atretic follicles suggests autophagy as a relevant mechanism during atresia in hake. Apoptosis genes p53 and caspase-3 were upregulated together with autophagocytosis marker genes ctsd and dapk1 in atretic ovaries. Vitellogenesis is the moment at which both apoptosis and autophagy are at their highest. 5S/18S rRNA ratio can be used as a non-biased method to rank the development stage of asynchronous developing hake ovaries.