Project description:To define regulation of tissue proteomes by Bmal1, daily feeding rhythm, and the interaction, we employed Bmal1-stopFL mice, which do not express the main transcriptional activator of the molecular clock, Bmal1, except in cre recombinase-expressing cells1,2 (Figure 1A). Bmal1-stopFL mice lacking cre (Bmal1 knockout, KO) are analogous to Bmal1-null mice and display severely impaired behavioral and molecular rhythms1-3. Hepatocyte-specific Alfp-cre and skeletal muscle-specific Hsa-cre genes were introduced to generate a single line wherein both hepatocyte and skeletal muscle Bmal1 were reconstituted (Liver+Muscle-RE), i.e., rescued (Smith, Koronowski et al. 2023). This approach had the benefit of analyzing liver and muscle from the same mice but comes with the qualification that the abundance of some proteins may be influenced by Bmal1 function in the other tissue, or by a synergistic effect of Bmal1 in both tissues, rather than through rescue of local Bmal1 function alone. Proteomic anlaysis was performed in liver and skeletal muscle.
Project description:Mice without cardiac Bmal1 function develop severe progressive heart failure with age. To examine the mechanism underlying the failing heart phenotype observed in heart-specific Bmal1 knockout mice, microarray analyses were performed. The analyses revealed that broad classes of genes regulating cellular energy metabolism were upregulated or downregulated in the heart tissues of heart-specific Bmal1 knockout mice compared with those of control animals. Heart total RNA extracted from six animals per genotype (control and heart-specific Bmal1 knockout) was pooled and then used for a microarray analysis.
Project description:To assess potential impact of intestine clock on the rhythmicity of peripheral tissues (liver, kidney and WAT), mice with Bmal1 specifically deleted in the intestine (Bmal1-iKO mice, showing loss of clock function in the intestine) were generated. We collected liver, kidney and WAT samples from Bmal1-iKO and control (Bmal1-flox) mice every 4 hours throughout a light/dark cycle, and subsequently performed transcriptomic analyses.
Project description:Obesity and liver diseases are associated with the disruption of the circadian clock that orchestrates mammalian physiology to optimize nutrient metabolism and storage. We show here that the activity of the circadian clock regulator BMAL1 is perturbed during liver fibrosis in humans. To understand the impact of BMAL1 perturbation in obesity and liver diseases, we assessed the impact of a high fat diet or leptin deficiency on Bmal1 knockout mice. While Bmal1 knockout mice were prone to obesity, they were protected against insulin resistance, hepatic steatosis, inflammation, and fibrosis. In addition to direct transcriptional regulation of metabolic programs by BMAL1, we show that adaptation disruption of the growth hormone and sex hormone pathways plays a critical role in this protection. Similar endocrine perturbations correlate with the development of liver fibrosis in humans, but were absent in hepatocyte specific Bmal1 knockout mice. This suggestsing that systemic endocrine perturbation associated with circadian disruptionthe disruption of BMAL1 activity is critical for the pathogenesis of metabolic and liver diseases.
Project description:Mice without cardiac Bmal1 function develop severe progressive heart failure with age. To examine the mechanism underlying the failing heart phenotype observed in heart-specific Bmal1 knockout mice, microarray analyses were performed. The analyses revealed that broad classes of genes regulating cellular energy metabolism were upregulated or downregulated in the heart tissues of heart-specific Bmal1 knockout mice compared with those of control animals.
Project description:ChIP-seqs of BMAL1, HNF4A, FOXA2, H3K4me1, and H3K27ac were profiled in mouse liver tissues upon Hnf4a or Bmal1 knockout. BMAL1, H3K4me1, and H3K27ac ChIP-seq were profiled in U2OS cells ectopically expressing HNF4A.
Project description:Obesity and liver diseases are associated with the disruption of the circadian clock that orchestrates mammalian physiology to optimize nutrient metabolism and storage. We show here that the activity of the circadian clock regulator BMAL1 is perturbed during liver fibrosis in humans. To understand the impact of BMAL1 perturbation in obesity and liver diseases, we assessed the impact of a high fat diet or leptin deficiency on Bmal1 knockout mice. While Bmal1 knockout mice were prone to obesity, they were protected against insulin resistance, hepatic steatosis, inflammation, and fibrosis. In addition to direct transcriptional regulation of metabolic programs by BMAL1, we show that adaptation of the growth hormone and sex hormone pathways plays a critical role in this protection. Similar endocrine perturbations correlate with the development of liver fibrosis in humans, suggesting that endocrine perturbation associated with circadian disruption is critical for the pathogenesis of metabolic and liver diseases.