Project description:Circadian rhythms are a series of endogenous autonomous 24-hour oscillations generated by the circadian clock. At the molecular level, the circadian clock is generated by a transcription-translation feedback loop, where BMAL1 and CLOCK transcription factors of the positive arm activate the expression of CRYPTOCHROME and PERIOD (PER) genes of the negative arm as well as the circadian clock-regulated genes. In this project, we aimed at finding the interactome of PER2 protein in human U2OS osteosarcoma cell line using proximity-dependent biotin identification (BioID) technique. U2OS clones overexpressing PER2-BioID2 or BioID2 were treated with dexamethasone in order to reset the circadian rhythm, and cells were then incubated in biotin-containing media for 12 hours to label the proteins in close proximity of PER2-BioID2. Samples were collected after 36 and 48 hours of the resetting to identify the labeled proteins by mass spectrometry. In addition to known interactors such as CRY1 and CRY2, many novel interactors were identified. In summary, we obtained a network of PER2 interactome and confirmed some of the novel interactions using classical the co-immunoprecipitation method.
Project description:The transcription-translation feedback loop, the core clock mechanism, is required for circadian rhythm. CRY protein, including CRY1 and CRY2, plays an important repressor role in the regulation of clock genes. However, other proteins, like PER1, PER2, NR1D1 and NR1D2, in the loop mask the transcriptional effects of CRY. This study provides data to find candidate genes specifically affected by CRY1 or CRY2 in mouse embryonic fibroblast (MEF) cells.
Project description:Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by synovitis and/or joint deterioration. Interstitial lung disease (ILD) is one of extra-articular manifestations of RA characterized by inflammation and/or fibrosis. Clinically relevant rheumatoid arthritis-related interstitial lung disease (RA-ILD) occurs in 10% of RA patients and is associated with poor prognosis. Although a poor prognosis has been reported, little is known about RA-ILD. Here, we report the first detailed transcriptomic analysis of the epithelial and immune cell populations in RA-ILD lungs at the single-cell level.
Project description:The microbiome in Dermatomyositis associated with Interstitial lung disease and rheumatoid arthritis associated with Interstitial lung disease
Project description:Obesity is recognized as a risk factor for triggering rheumatoid arthritis (RA), and it can worsen joint deformities and diminish the quality of life in patients with RA. The reduction of body weight in obese individuals is believed to alleviate RA symptoms。
Project description:We show that the cyclin-dependent kinase 5 (CDK5) regulates the mammalian circadian clock via phosphorylation of PER2. CDK5 phosphorylated PER2 at serine residue 394 (S394) as shown by an in vitro kinase assay.
Project description:The expression of clock genes are co-regulated by BMAL1 and CLOCK in all tissue including kidney. Whether these clock-regualted genes can be affected by melatonin still unclaer. To further examine the possible mechanism and biological consequence, we depleted BMAL1 or CLOCK with small interfering RNA (siRNA) and treated cells with melatonin. Then, we used microarray analyses to identify clock genes regulated by melatonin in renal tubular epithelial cell.
Project description:Circadian pace is modulated by light intensity, known as the Aschoff’s rule, with largely unrevealed mechanisms. Here we report that photoreceptor CRY2 mediates blue light input to circadian clock by directly interacting with clock core component PRR9 in blue light dependent manner. This physical interaction dually blocks the accessibility of PRR9 protein to its co-repressor TPL/TPRs and the resulting kinase PPKs. Notably, phosphorylation of PRR9 by PPKs is critical for its DNA binding and repressive activity, hence to ensure proper circadian speed. Given the labile nature of CRY2 in strong blue light, our findings provide a mechanistic explanation for Aschoff’s rule in plants, i.e., blue light triggers CRY2 turnover in proportional to its intensity, which accordingly releasing PRR9 to fine tune circadian speed. Our findings not only reveal a novel network mediating light input into circadian clock, but also unmask a mechanism by which Arabidopsis circadian clock sensing light intensity.
Project description:Skeletal muscle has remarkable capacity to regenerate upon injury due to the presence of satellite cells. The maintenance and function of satellite cells are regulated by circadian clock. Cryptocrhome 2 (CRY2) is a key component of the circadian clock and its role in skeletal muscle regeneration remains controversial. Here, we report that CRY2 is down-regulated during muscle regeneration. Using the satellite cell specific CRY2 knockout mice (CRY2scko), we show that deletion of CRY2 enhances muscle regeneration. Single myofiber analysis showed that deletion of CRY2 enhances satellite cell self-renewal. In the absence of CRY2, the ERK1/2 and JNK1/2 signaling pathways become activated, which phosphorylates the transcription factor ETS1, which in turn binds to the promoter of PAX7 to induce its transcription. CRY2 deficient myoblasts survived better in ischemic muscle. Deletion of CRY2 also alleviated myopathy in mdx mice. Therefore, CRY2 plays an essential role in regulating satellite cell function and skeletal muscle regeneration.
