What Can Frogs Tell Us About Childhood Adversity? Whitman Fellow Sally Seraphin Explores

Sally Seraphin is using red-eyed tree frogs to study the effects of early childhood adversity. Credit: Geoff Gallice

Adverse childhood experiences (ACEs), which include physical and emotional abuse, neglect, caregiver mental illness, and household violence, can be challenging to study in the lab. When studying ACEs in humans, ethical concerns limit the questions a researcher can ask. 

Sally Seraphin, an E.E. Just Fellow in the MBL Whitman Center this summer, is working on a solution: studying neotropical frogs. Two species in particular, the red-eyed tree frog and glass frog, offer a unique avenue for examining the behavioral and neurobiological effects of early life stressors. 

Sally Seraphin was inspired by the work done with Xenopus at MBL and decided to apply it to neotropical frogs. Credit: Sally Seraphin
Sally Seraphin was inspired by the work done with Xenopus at MBL and decided to apply it to neotropical frogs. Credit: Sally Seraphin

Throughout life, organisms have to juggle three priorities: survival, growth, and reproduction. In a stable, safe environment, young organisms can afford to take it slow when developing and maturing, which affords them an advantage later in life in terms of immunity and long-term physical health. 

On the other hand, organisms that experience major challenges early in life tend to sacrifice longevity for immediate survival. In humans, this can manifest as quicker cellular aging and earlier puberty in response to childhood traumatic stress. 

In frog embryos, the imminent threat of a snake attack can lead them to hatch out of their cozy, jelly-filled egg earlier than normal. Seraphin hopes to understand whether these two responses - premature development in humans and “escape hatching” in frogs - share similar underlying neuroendocrine mechanisms.

To study this at the MBL, Seraphin exposes frog embryos to stressors just a few days after they’re laid. In the absence of menacing snakes in the lab, Seraphin simulates snake-like vibration by gently rubbing the surface of the eggs until they hatch, which occurs up to three days earlier than eggs that are left undisturbed. Studying the brains, immune systems, and behavior of frogs that have hatched early could offer “insights into which brain-body systems are driving the timing and tempo of life history under stress,” says Seraphin.

Though in her lab at Trinity College she has studied chimpanzees, rhesus monkeys, and humans, Seraphin was excited to explore new model organisms at MBL this summer.

Seraphin first visited MBL when she was an REU student in nearby Buzzards Bay, and returned last summer as a SEE-Diversity (Scholarships to Enhance and Empower Diversity) workshop participant. 

“The E.E. Just Fellowship provided the perfect opportunity for me to return to MBL and learn transferable skills and techniques that have contributed to [research] success with Xenopus to my neotropical frogs,” she says. The MBL is the home of the National Xenopus Resource, a national facility for maintaining Xenopus lines for biomedical research, and for training in their use.

Seraphin and her students, Anastasia Hanifin and Shirin Dadina, successfully bred red-tree frogs in the lab this summer. Credit: Sally Seraphin
Seraphin and her students, Anastasia Hanifin and Shirin Dadina, successfully bred red-tree frogs in the lab this summer. Credit: Sally Seraphin

So far this summer, Seraphin’s team has become the first in about a dozen years to successfully breed red-eyed tree frogs in the lab. With around 300 new specimens, the team plans to study how early hatching shapes the patterning of gene expression and neuroanatomical development.

“Our preliminary growth data reveal significant developmental acceleration in body mass of stress-induced early hatching tadpoles, compared to those allowed to hatch on their own,” reports Seraphin. “This is the first piece of evidence to support that laboratory red eyes could help us understand developmental acceleration after early stress in humans.” 

This work could help researchers develop treatment for the millions of Americans who live with the long-term effects of childhood adversity.