Regulation of circadian behavioural output via clock-responsive miR-276b

Cardiac Timeless Trans-Organically Regulated by miR-276 in Adipose Tissue Modulates Cardiac Function

The interconnection between cardiac function and circadian rhythms is of great importance. While the role of the biological clock gene Timeless (Tim) in circadian rhythm has been extensively studied, its impact on cardiac function remains largely been unexplored. Previous research has provided experimental evidence for the regulation of the heart by adipose tissue and the targeting of miR-276a/b on Timeless. However, the extent to which adipose tissue regulates cardiac Timeless genes trans-organically through miR-276a/b, and subsequently affects cardiac function, remains uncertain. Therefore, the objective of this study was to investigate the potential trans-organ modulation of the Timeless gene in the heart by adipose tissue through miR-276a/b. We found that cardiac-specific Timeless knockdown and overexpression resulted in a significant increase in heart rate (HR) and a significant decrease in Heart period (HP), diastolic intervals (DI), systolic intervals (SI), diastolic diameter (DD), and systolic diameter (SD). miR-276b systemic knockdown resulted in a significant increase in DI, arrhythmia index (AI), and fractional shortening (FS) significantly increased and SI, DD and SD significantly decreased. Adipose tissue-specific miR-276a/b knockdown and miR-276a overexpression resulted in a significant increase in HR and a significant decrease in DI and SI, which were improved by exercise intervention. This study presents a novel finding that highlights the significance of the heart circadian clock gene Timeless in heart function. Additionally, it demonstrates that adipose tissue exerts trans-organ modulation on the expression of the heart Timeless gene via miR-276a/b.

Age-related ceRNA networks in adult Drosophila ageing

As Drosophila is an extensively used genetic model system, understanding of its regulatory networks has great significance in revealing the genetic mechanisms of ageing and human diseases. Competing endogenous RNA (ceRNA)-mediated regulation is an important mechanism by which circular RNAs (circRNAs) and long non-coding RNAs (lncRNAs) regulate ageing and age-related diseases. However, extensive analyses of the multiomics (circRNA/miRNA/mRNA and lncRNA/miRNA/mRNA) characteristics of adult Drosophila during ageing have not been reported. Here, differentially expressed circRNAs and microRNAs (miRNAs) between 7 and 42-day-old flies were screened and identified. Then, the differentially expressed mRNAs, circRNAs, miRNAs, and lncRNAs between the 7- and 42-day old flies were analysed to identify age-related circRNA/miRNA/mRNA and lncRNA/miRNA/mRNA networks in ageing Drosophila. Several key ceRNA networks were identified, such as the dme_circ_0009500/dme_miR-289-5p/CG31064, dme_circ_0009500/dme_miR-289-5p/frizzled, dme_circ_0009500/dme_miR-985-3p/Abl, and XLOC_027736/dme_miR-985-3p/Abl XLOC_189909/dme_miR-985-3p/Abl networks. Furthermore, real-time quantitative PCR (qPCR) was used to verify the expression level of those genes. Those results suggest that the discovery of these ceRNA networks in ageing adult Drosophila provide new information for research on human ageing and age-related diseases.