Title: Impact of light and diet on mitochondria-mediated regulation of adult stem cells in Drosophila melanogaster.

Abstract: 

Light serves as the primary zeitgeber for the circadian system, facilitating its integration and entrainment with the external environment. This can activate certain photoreceptors in the cell, changing the circadian system's downstream mechanisms, to play crucial roles in regulating the body's internal clock and coordinating physiological processes. Interestingly, it has been demonstrated that the circadian clock regulates mitochondria, which serve as the intermediary hub for energy metabolism. This regulation affects both, the structure and function of mitochondria, influencing various metabolic processes. Dynamin-related protein 1(Drp1) is critical as it is recruited to mitochondria and regulates their fission. This protein plays a pivotal role in maintaining cellular homeostasis, energy production, and stress response through its regulation of mitochondrial dynamics. Morphological changes in mitochondria, influenced by factors like nutrient availability, serve as early distinctions between stem cells and differentiated cells, underscoring the significance of Drp1 in stem cell energy metabolism. Building on the lab's prior expertise in fly ovarian stem cells and considering the ovary's significance in housing both germline and somatic stem cells, it provides an excellent model for studying the influence of these external factors on adult stem cell behaviour. Our preliminary study suggests an interesting interaction between external light/dark cycles collaborating with a high-protein diet supplement in maximizing Drosophila egg production. We saw a similar impact on the localization of Drp1 on mitochondria in ovarian cells using super-resolution microscopy and colocalization analyses. Our primary focus was to explore how stem cells respond to the combined effects of light and a high-protein diet. Therefore, we hypothesize that yeast enhances Drp1 recruitment to mitochondria, but is potentially repressed by light. If light-induced inhibition of Drp1 leads to mitochondrial fusion, this phenomenon could contribute to sustaining the stemness of adult stem cells, potentially influencing their self-renewal and differentiation capabilities. To test this hypothesis and explore these findings, lineage tracing experiments involving stem cells, gene manipulation strategies, and high-resolution microscopy will be employed. Light has been used as a non-invasive therapeutic model in stem cell biology due to its potential benefits in areas such as wound healing, dermatology, mental health and sleep disorders. Therefore, integrating the study of diet with light in the context of stem cell biology may offer a more holistic understanding of how environmental factors collectively shape cellular response.

About the Speaker:

Yoshita Sriramkumar is currently a PhD Candidate at the Mitochondrial Structure-Function Lab, working under the guidance of Dr. Kasturi Mitra in the Department of Biology at Ashoka University. Her journey in Biology began with a keen interest that eventually led her to earn a B.E. degree in Biotechnology from BMS College of Engineering, Bengaluru. Subsequently, she delved into research as a Junior Research Fellow in a Circadian rhythm lab at Ashoka University before embarking on her doctoral studies in Dr. Mitra's lab. Beyond her academic pursuits, Yoshita is passionate about music and is a Carnatic vocalist. Additionally, she has received training in Bharatanatyam and Indian contemporary dance forms, expressing her appreciation for various art forms, whether in the lab or elsewhere.