- Author: Kathy Keatley Garvey
And how do animals use changes in day length and temperature to adapt their physiology and behavior to seasonal environmental changes?
Those are the questions that UC Davis postdoctoral researcher Sergio Hidalgo Sotelo asked himself, and now newly published research that he spearheaded in the laboratory of molecular geneticist-physiologist Joanna Chiu—building on previous Chiu lab research--sheds more light on the topic.
The research article, “Seasonal Cues Act Through the Circadian Clock and Pigment Dispersing Factor to Control EYES ABSENT and Downstream Physiological Changes,” appears in the current edition of the journal Current Biology.
Sotelo, a Pew Latin American Fellow in the Biomedical Sciences fellow in the lab of Professor Chiu, vice chair of the UC Davis Department of Entomology and Nematology, collaborated with Chiu and two lab members: Christine Tabuloc, a doctoral candidate, and Maribel Anguiano, now a doctoral student in the UC Davis Neuroscience graduate program and a former member of National Institutes of Health Postbaccalaureate Research Education Program (PREP).
“This work,” Chiu said, “certainly helps us progress towards a more complete picture of how animal seasonality is regulated at the molecular and cellular level. Excitingly, it also raises many more interesting questions, which Sergio and our team cannot wait to answer.”
Their summary:
Organisms adapt to seasonal changes in photoperiod and temperature to survive; however, the mechanisms by which these signals are integrated in the brain to alter seasonal biology are poorly understood. We previously reported that EYES ABSENT (EYA) shows higher levels in cold temperature or short photoperiod and promotes winter physiology in Drosophila. Nevertheless, how EYA senses seasonal cues is unclear. Pigment-dispersing factor (PDF) is a neuropeptide important for regulating circadian output rhythms. Interestingly, PDF has also been shown to regulate seasonality, suggesting that it may mediate the function of the circadian clock in modulating seasonal physiology. In this study, we investigated the role of EYA in mediating the function of PDF on seasonal biology. We observed that PDF abundance is lower on cold and short days as compared with warm and long days, contrary to what was previously observed for EYA. We observed that manipulating PDF signaling in eya+ fly brain neurons, where EYA and PDF receptor are co-expressed, modulates seasonal adaptations in daily activity rhythm and ovary development via EYA-dependent and EYA-independent mechanisms. At the molecular level, altering PDF signaling impacted EYA protein abundance. Specifically, we showed that protein kinase A (PKA), an effector of PDF signaling, phosphorylates EYA promoting its degradation, thus explaining the opposite responses of PDF and EYA abundance to changes in seasonal cues. In summary, our results support a model in which PDF signaling negatively modulates EYA levels to regulate seasonal physiology, linking the circadian clock to the modulation of seasonal adaptations.”
Sotelo, who specializes in chronobiology (the study of biological rhythms), molecular genetics and biochemistry, won the 2021 Young Neuroscientist Symposium Award at the meeting of the Chilean Society for Neuroscience, Chile, and received a merit award for his presentation at the 2022 Society for Research on Biological Rhythms (SRBR) Biennial Conference in Amelia Island, Florida.
A native of Puente Alto, Santiago, Chile, Sotelo joined the Chiu lab as a postdoctoral fellow in the summer of 2020. He is one of 10 post-docs from across Latin America—including Argentina, Brazil, Chile, Mexico, Peru, and Uruguay—to receive two years of funding to conduct research. The fellows work under the mentorship of prominent biomedical scientists, including alumni of the Pew Scholars Program in the Biomedical Sciences.
Sotelo holds three degrees from Pontificia Universidad Católica de Chile: a bachelor's degree in biochemistry, with distinction (2015), a master's degree in neurochemistry (2017) and a doctorate in cellular and molecular biology, with distinction (2020). Also in 2020, he received a doctorate in sensory physiology and animal. Behavior from the University of Bristol, Bristol, UK.
Resource:
EYES ABSENT and TIMELESS Integrate Photoperiodic and Temperature Cues to Regulate Seasonal Physiology in Drosophila, published June 15, 2020, Proceedings of the National Academy of Sciences (PNAS), lead author Antoine Abrieux and co-authors Joanna Chiu, Yao Cai, and Yongbo Xue.
- Author: Kathy Keatley Garvey
Sotelo, a researcher in the laboratory of molecular geneticist and physiologist Joanna Chiu, professor and vice chair of the UC Davis Department of Entomology and Nematology, will speak at 4:10 p.m. Plans are to record the seminar for later viewing.
In his abstract, Sotelo relates: “As genome association technologies improve, we have more information regarding the genetic components underlying neurodegenerative and neuropsychiatric disorders such as Alzheimer's, Parkinson's, and schizophrenia. Drosophila melanogaster offers a genetically tractable in vivo system that can be used to perform genetic screens and characterization of genes associated with complex disorders. By combining physiological and behavioral analyses, my work aims to understand the molecular mechanism and neuronal networks involved in some of these conditions.”
“Schizophrenia is a condition that is characterized by its debilitating and poorly understood symptoms," he pointed out. "By studying the genetic component of this disorder, we aim to untangle the mechanisms behind those symptoms. This could potentially help us to develop new and more effective treatments. Using a similar approach would give us insights better understanding of others disorders like Alzheimer's and Parkinson's.”
Said Professor Chiu: “Sergio's exciting thesis research highlights the value of Drosophila as an animal model to study biological processors. To many, it is probably surprising to hear that this tiny insect is constantly used as an animal model to study complex human diseases such as Alzheimer's and Parkinson's. In fact, there are quite a number of similarities between fly and human physiological systems, even in the brain.”
Sotelo joined the Chiu lab as a postdoctoral fellow in the summer of 2020. “Despite the difficult situation brought on by COVID, Sergio is making significant progress in his research on biological rhythms," Chiu said. "He has brought his expertise in neurogenetics, infused the lab with creative energy, and contributed to the training and growth of younger investigators in the lab. Recently, he was named a Pew Latin American Fellow in the Biomedical Sciences, a prestigious award for a well-deserved scientist.”
A native of Puente Alto, Santiago, Chile, Sotelo is one of 10 post-docs from across Latin America—including Argentina, Brazil, Chile, Mexico, Peru, and Uruguay—to receive two years of funding to conduct research. The fellows work under the mentorship of prominent biomedical scientists, including alumni of the Pew Scholars Program in the Biomedical Sciences.
The UC Davis Department of Entomology and Nematology seminars are held on Wednesdays at 4:10 p.m. and include both in-person and virtual lectures. All in-person seminars are held in 122 Briggs Hall, while the virtual seminars are broadcast on Zoom. For more information, contact seminar coordinator Shahid Siddique, at ssiddique@ucdavis.edu.
- Author: Kathy Keatley Garvey
A native of Puente Alto, Santiago, Chile, he joined the Chiu lab in 2020 and is exploring the molecular and neural circuits that regulate seasonal biology in animals.
Under this Pew program, young scientists from Latin America receive postdoctoral training in the United States, “giving them an opportunity to further their scientific knowledge by promoting exchange and collaboration between investigators in the United States and Latin America—ultimately resulting in advances in research in Latin America,” Pew spokesperson Abigail Major said.
Sergio is one of 10 post-docs from across Latin America—including Argentina, Brazil, Chile, Mexico, Peru, and Uruguay—to receive two years of funding to conduct research. The fellows will work under the mentorship of prominent biomedical scientists, including alumni of the Pew Scholars Program in the Biomedical Sciences.
“Sergio's academic and research track record is outstanding,” said Chiu, associate professor and vice chair of the Department of Entomology and Nematology. “Although he has only worked in my laboratory for less than a year, I have been very impressed by his drive, independence, ingenuity, and intellect. Given his long-standing interest in understanding how neuronal mechanisms regulate behavior and physiology, his research goals align very well with my laboratory. I am excited he has been named a Pew Latin American Fellow; it is very well deserved. I look forward to partnering with him to study regulation of seasonal biology."
Hidalgo Sotelo wrote his dissertation on “Using Drosophila to Model Schizophrenia Symptoms.” He was awarded a dual doctorate in physiology and pharmacology in 2020 from the University of Bristol, and Pontificia Universidad Católica de Chile. He also holds a master's degree in biological science from Pontificia Universidad Católica de Chile and a bachelor's degree in biochemistry there.
Of his research in the Chiu lab, he explained: “Animals use environmental cues to match their behaviors with the season: as temperatures fall and days grow shorter, birds fly south, and fruit flies curtail their reproduction, Hidalgo Sotelo said. “But little is known about the mechanisms that allow animals to synchronize with the calendar. I will work on elucidating this machinery, using an array of cutting-edge techniques in cell and molecular biology, neurogenetics, and genomics, aiming to identify the molecules that contribute to the seasonal oscillations of EYA, a key component of the seasonal timer previously described by a number of groups, including Dr. Chiu's lab. These findings will broaden our understanding of seasonal biology and could lead to new approaches for treating disorders that display seasonality, including infectious diseases and seasonal affective disorder.”
Another Pew postdoctoral fellow is Mariana Duhne Aguayo of the UC San Francisco lab of Joseph Berke where she is mapping the neural circuits that calibrate how swiftly animals move.
Other postdocs are training in labs at Harvard University, New York University Grossman School of Medicine, Texas Tech University Health Sciences Center, University of Virginia, Washington University School of Medicine, Massachusetts General Hospital, and New York University Langone Health.
Pew Trust officials also announced the recipients of the Pew Scholars in Biomedical Sciences, who include Bennett Penn, assistant professor in the UC Davis Department of Medicine's Division of Infectious Diseases. The Pew Scholars Program in the Biomedical Sciences provides funding to young investigators of outstanding promise in science relevant to the advancement of human health.
