Assessment of exosome circadian rhythmicity in mice

• Grant number: 19/08038-3
• Support Opportunities: Scholarships in Brazil - Master
• Effective date (Start): October 01, 2019
• Effective date (End): March 31, 2022
• Field of knowledge: Biological Sciences - Physiology - Physiology of Organs and Systems
• Principal Investigator: Marcelo Alves da Silva Mori
• Grantee: Matheus Pedroni Negrão
• Host Institution: Instituto de Biologia (IB). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Associated research grant: 17/01184-9 - CAMeLEOm: cross-species analysis of metabolic, lifespan effects and omics of dietary restriction mimetics, AP.TEM

Abstract

The circadian rhythm is a highly evolutively conserved mechanism that exists in virtually all mammalian tissues. The translational clock machinery controls the expression of many genes in a tissue-specific manner, yet most of the rhythmicity at the protein level results from post-transcriptional modifications. MicroRNAs (miRNAs) arise in this context as an important link between post-transcriptional regulation and metabolism, and many miRNAs present rhythmic expression or modulate the expression of rhythmic genes. Previous results suggest that adipose tissue contributes with the majority of the circulating miRNA pool, especially those carried by exosomes, which mediate a type of intertissue communication of special importance. Mouse tissues exhibit strong synchronization with each other and, given the role of exosomes in dynamic intertissue communication, we propose that there is rhythmicity in circulating exosomes. This hypothesis is reinforced by preliminary analysis showing that 22 miRNAs potentially transferred from brown adipose tissue to the liver are rhythmic, but without rhythmic transcription in the liver. We will use mice in 6 different time points (encompassing a 24h period) to isolate exosomes and characterize the purity of the isolated fraction. The expression of the selected 22 miRNAs will be evaluated in circulating exosomes, brown adipose tissue and liver. The expression of those miRNAs will be compared between control and AdicerKO (adipose tissue Dicer knockout) animals. Those that present circadian rhythmicity will have their corresponding primary miRNAs assessed in the tissues and in vitro experiments will be used to confirm whether brown adipocytes release exosomal miRNAs in a rhythmic manner. (AU)