Analysis of molecular changes of the nervous system in C. elegans upon circadian rhythm entrainment
Description: Caenorhabditis elegans are ectothermic and are thus subject to diurnal and seasonal changes in temperature, specifically soil temperature where they naturally reside. C. elegans sense temperature changes through specific thermosensory neurons and respond through changes in intracellular signaling. These neurons are essential for the regulation of longevity (Lee & Kenyon, 2009). In the laboratory setting, single and multiple, short-term heat shocks have been shown to increase lifespan in C. elegans (Zhou et al, 2011). The phosphoproteome of adult C. elegans after short-term mild heat stress showed a wide range of signaling changes, notably to proteins associated with lifespan determination (Huang et al, 2020). C. elegans can be entrained to a circadian rhythm by the application of temperature cycles (Olmedo et al, 2012). However, it remains unclear if temperature-induced circadian rhythms have a protective effect on longevity compared to a single short-term heat shock. Thus, we aim to elucidate whether circadian rhythms entrained by temperature cycling have a positive effect on longevity through the analysis of the changes to mRNA expression and the proteome, specifically in the nervous system.
Hypothesis: Circadian rhythm temperature shifts increase C. elegans longevity and result in mRNA and proteome changes to the nervous system.
Aim1: How do oscillating circadian-like temperature shifts affect C. elegans longevity?
We will use an automated platform with precise temperature control (Le et al, 2020). We will employ circadian rhythm paradigms that mimics naturally occurring temperature oscillation from to 12°C to 22 °C and compare those to a constant state as well as a single heat shock to determine their impact on C. elegans longevity. Longevity will be assessed by measuring locomotion, touch response, and pharyngeal pumping. We will determine the circadian entrainment paradigm that has the most beneficial effect on longevity, which will be used in Aim 2.
Aim2: Which pathways are activated/repressed in the nervous system during and after circadian temperature entrainment?
We will utilize Ribotag technology with RNAseq and TurboID fused to a fluorescent protein with LC/MS to identify actively translating mRNAs (Wester et al, 2023) and proteins and post-translational modifications, respectively in the nervous system using neuron-specific promoters. Inducible TurboID in C. elegans is established (Artan et al, 2021). We will determine the overlap between the RNA and proteome datasets and perform pathway analyses using computational tools. Promising candidates will be validated by tissue-specific RNAi, CRISPR-Cas9 technology and functional assays to elucidate underlying mechanisms.
Conclusion: We will elucidate neuronal molecular mechanisms regulating the responses to naturally occurring temperature oscillations and their effect on the animal’s lifespan.
Funder: Human Frontier Science Program
Amount:
Funding type: award
Start date: 2024-05-01
End date: 2027-04-30
Investigator: Kristin Dahl
Institution: Biozentrum University of Basel
Subfield: Aging
Domain: Life Sciences
Funded outputs count: 0
Funder award ID: LT0035/2024-L
OpenAlex ID: G4300260622