Transcriptome Analysis Reveals Key Gene Expression Changes in Blue Catfish Sperm in Response to Cryopreservation

Int J Mol Sci. 2022 Jul 10;23(14):7618. doi: 10.3390/ijms23147618.

Abstract

The hybrids of female channel catfish (Ictalurus punctatus) and male blue catfish (I. furcatus) account for >50% of US catfish production due to superior growth, feed conversion, and disease resistance compared to both parental species. However, these hybrids can rarely be naturally spawned. Sperm collection is a lethal procedure, and sperm samples are now cryopreserved for fertilization needs. Previous studies showed that variation in sperm quality causes variable embryo hatch rates, which is the limiting factor in hybrid catfish breeding. Biomarkers as indicators for sperm quality and reproductive success are currently lacking. To address this, we investigated expression changes caused by cryopreservation using transcriptome profiles of fresh and cryopreserved sperm. Sperm quality measurements revealed that cryopreservation significantly increased oxidative stress levels and DNA fragmentation, and reduced sperm kinematic parameters. The present RNA-seq study identified 849 upregulated genes after cryopreservation, including members of all five complexes in the mitochondrial electron transport chain, suggesting a boost in oxidative phosphorylation activities, which often lead to excessive production of reactive oxygen species (ROS) associated with cell death. Interestingly, functional enrichment analyses revealed compensatory changes in gene expression after cryopreservation to offset detrimental effects of ultra-cold storage: MnSOD was induced to control ROS production; chaperones and ubiquitin ligases were upregulated to correct misfolded proteins or direct them to degradation; negative regulators of apoptosis, amide biosynthesis, and cilium-related functions were also enriched. Our study provides insight into underlying molecular mechanisms of sperm cryoinjury and lays a foundation to further explore molecular biomarkers on cryo-survival and gamete quality.

Keywords: DNA fragmentation; Ictalurus furcatus; Ictalurus punctatus; RNA sequencing; apoptosis; hybrid catfish; motility; oxidative stress; sperm quality; sperm storage.

MeSH terms

  • Animals
  • Biomarkers / metabolism
  • Catfishes* / genetics
  • Catfishes* / metabolism
  • Cryopreservation / methods
  • Female
  • Gene Expression Profiling
  • Ictaluridae* / genetics
  • Male
  • Reactive Oxygen Species / metabolism
  • Semen / metabolism
  • Sperm Motility
  • Spermatozoa / metabolism
  • Transcriptome

Substances

  • Biomarkers
  • Reactive Oxygen Species

Grants and funding

This research is supported by an Alabama Agriculture Experiment Station Agriculture Research Enhancement, Exploration, and Development (AAES-AgR-SEED) award, and USDA National Institute of Food and Agriculture Hatch projects 1018100 and 1013854. This project was supported by Agriculture and Food Research Initiative Competitive Grant no. 2020-67015-31874 from the USDA National Institute of Food and Agriculture. The Ocean University of China-Auburn University (OUC-AU) Joint Center Grants Program (#202010) also supported this research. X.W. was supported by a National Science Foundation EPSCoR RII Track-4 award (1928770) and a laboratory start-up fund from Auburn University College Veterinary Medicine. H.W. is supported by the Auburn University Presidential Graduate Research Fellowship and College of Veterinary Medicine Dean’s Fellowship. H.W. and Y.Z. were also supported by the China Scholarship Council.