Oral Presentation SETAC Asia-Pacific Virtual Conference 2022

Transcriptomic insights into the developmental delays in F1 oyster larvae from parents exposed to the synthetic estrogen, 17α-ethinylestradiol (EE2) (#70)

Rafiquel Islam 1 2 , Richard Man Kit Yu 1 , Wayne A. O’Connor 3 , Xiao Alan Lin 4 , Keng Po Lai 5 , Geoff R. MacFarlane 1
  1. School of Environmental and Life Sciences, The University of Newcastle, Callaghan, Newcastle, NSW 2308, Australia
  2. Department of Applied Chemistry and Chemical Engineering, Islamic University, Kushtia 7003, Bangladesh
  3. New South Wales Department of Primary Industries, Port Stephens Fisheries Institute, Taylors Beach, NSW 2316, Australia
  4. Department of Psychiatry, Icahn School of Medicine at Mount Sinai, , New York, USA
  5. Laboratory of Environmental Pollution and Integrative Omics, Guangxi Key Laboratory of Tumor Immunology and Microenvironmental Regulation, , Guilin Medical University, , Guilin, 530022, , China

The synthetic estrogen, 17α-ethinylestradiol (EE2) is a ubiquitous endocrine disrupting chemical (EDC) in the aquatic environment and can impede the embryonic and larval development of oysters. However, it remains elusive whether parental (F0) exposure to EE2 can modulate these processes in the unexposed F1 offspring through transcriptomic regulation. In this study, we assessed the effect of parental exposure of the Sydney rock oyster (Saccostrea glomerata) to EE2 at an environmentally relevant concentration (50 ng/L) for 3 weeks. We observed that the parental exposure reduced the survival and fitness of D-veligers at 1 and 2 dpf, respectively, and caused shell length reduction in 7 dpf larvae. The transcriptional response of the unexposed larvae was assessed through RNA sequencing. A total of 1,064 differentially expressed genes (DEGs) were found in larvae from parents of both sexes treated (FTMT) while fewer numbers of DEGs, 258 and 7, were detected in larvae from the maternal (FTMC) and paternal (FCMT) alone treatment groups, respectively. Subsequent qPCR verification of selected DEGs indicated that genes related to ATP synthesis/energy regulation/mitochondrion membrane functioning (ATP5F1D, ATP5MF, EMRE, TIM44, and UQCRFS1), larval growth and development (CHPF), gene transcription/promoter responses to various activators and repressors (TAF6), and antioxidant defence against oxidative stress (Ec-SOD) were significantly downregulated. Furthermore, gene ontology (GO) analysis revealed significant enrichment of DEGs concerning with various biological, cellular and molecular functions, with pronounced effects observed in the FTMT and FTMC treatment groups. A similar pattern was also observed in the KEGG pathways analysis. Overall, the transcriptomic adjustments observed in this study provide important mechanistic insights into the phenotypic traits of oyster larvae derived from parental exposure to EE2.