Transcriptomic Profiling of Fibropapillomatosis in Green Sea Turtles (Chelonia mydas) From South Texas.

Nicholas B Blackburn,Jeff George,Brian A Stacy,Nina Nahvi,Megan Keniry,Juan M Peralta,Ignacio Martinez Escobedo,Marcelo Leandro,Joanne E Curran,Ana Cristina Leandro,Thomas W Demaar,John Blangero,Mariana A Devlin

doi:10.3389/fimmu.2021.630988

Abstract

Sea turtle fibropapillomatosis (FP) is a tumor promoting disease that is one of several threats globally to endangered sea turtle populations. The prevalence of FP is highest in green sea turtle (Chelonia mydas) populations, and historically has shown considerable temporal growth. FP tumors can significantly affect the ability of turtles to forage for food and avoid predation and can grow to debilitating sizes. In the current study, based in South Texas, we have applied transcriptome sequencing to FP tumors and healthy control tissue to study the gene expression profiles of FP. By identifying differentially expressed turtle genes in FP, and matching these genes to their closest human ortholog we draw on the wealth of human based knowledge, specifically human cancer, to identify new insights into the biology of sea turtle FP. We show that several genes aberrantly expressed in FP tumors have known tumor promoting biology in humans, including CTHRC1 and NLRC5, and provide support that disruption of the Wnt signaling pathway is a feature of FP. Further, we profiled the expression of current targets of immune checkpoint inhibitors from human oncology in FP tumors and identified potential candidates for future studies.

Highlights

Sea turtle fibropapillomatosis (FP) is a tumor promoting disease that occurs globally in all seven species of sea turtles
We aimed to study FP in a geographically distinct population of green turtles, hypothesizing that both similarities and differences will emerge between the transcriptomic profiles of FP tumors in Texas and Florida
During 2017–2018, 35 tissue samples were collected from nine green turtles undergoing rehabilitation at Sea Turtle Inc., after stranding at South Padre Island, Texas

Summary

Introduction

Sea turtle fibropapillomatosis (FP) is a tumor promoting disease that occurs globally in all seven species of sea turtles. The species known for having the highest FP prevalence is the green sea turtle (Chelonia mydas) [1]. FP was first reported over 80 years ago in captured green turtles from the Florida Keys, USA [2]. Despite sustained and/or increased detection in Florida [3, 4], Hawaii [5,6,7], and other areas globally [8, 9], FP was not detected in Texas, USA until 2010 [10]. Since the prevalence of this disease in Texas has increased dramatically.

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