Potential role of ATM in hepatocyte endocytosis of ApoE-deficient, ApoB48-containing lipoprotein in ApoE-deficient mice

Weighted gene coexpression network analysis identifies specific transcriptional modules and hub genes related to intramuscular fat traits in chicken breast muscle

Intramuscular fat (IMF) traits are important factors that influence meat quality. However, the molecular regulatory mechanisms that underlie this trait in chickens are still poorly understood at the gene coexpression level. Here, we performed a weighted gene coexpression network analysis between IMF traits and transcriptome profile in breast muscle in the Chinese domestic Gushi chicken breed at 6, 14, 22, and 30 weeks. A total of 26 coexpressed gene modules were identified. Six modules, which included the dark gray, purple, cyan, pink, light cyan, and blue modules, showed a significant positive correlation (P < 0.05) with IMF traits. The strongest correlation was observed between the dark gray module and IMF content (r = 0.85; P = 4e-04) and between the blue module and different fatty acid content (r = 0.87~0.91; P = 5e-05~2e-04). Enrichment analysis showed that the enrichment of biological processes, such as fatty acid metabolic process, fat cell differentiation, acylglycerol metabolic process, and glycerolipid metabolism were significantly different in the six modules. In addition, the 32, 24, 4, 7, 6, and 25 hub genes were identified from the blue, pink, light cyan, cyan, dark gray, and purple modules, respectively. These hub genes are involved in multiple links to fatty acid metabolism, phospholipid metabolism, cholesterol metabolism, diverse cellular behaviors, and cell events. These results provide novel insights into the molecular regulatory mechanisms for IMF-related traits in chicken and may also help to uncover the formation mechanism for excellent meat quality traits in local breeds of Chinese chicken.

Multifaceted roles of ATM in autophagy: From nonselective autophagy to selective autophagy

The ataxia-telangiectasia mutated (ATM) protein kinase is best known for its critical nuclear roles in the DNA damage response (DDR), cell cycle checkpoints, and the maintenance of gene stability. In this review, we highlight the multifaceted cytoplasmic functions of ATM in autophagy. We focused on the functions of ATM in nonselective autophagy in cancer. An Oncomine database analysis showed a tight association between ATM and autophagy in various cancers. In particular, its mechanisms in nonselective autophagy, those induced by ionizing radiation (IR), are illustrated in detail and involve the MAPK14 pathway, mTOR pathway, and Beclin1/PI3KIII complexes. Recently, an increasing number of studies revealed that autophagy could also be highly selective. We additionally emphasized the novel roles of ATM in selective autophagy, including mitophagy, pexophagy, and lipophagy. The regulation of these processes mainly involves ATM-PEX5, ATM-AMPK-TSC2-mTORC1-ULK1, PPM1D-ATM-MTOR, PINK I/Parkin, and NAD+/SIRT1. We aimed to provide new perspectives on the importance of ATM in the diverse field of autophagy. The intricate regulation of ATM in autophagy still requires further investigation, which would enhance our understanding of its role in cell dynamics and homeostasis. SIGNIFICANCE OF THE STUDY: Our review highlighted the multifaceted cytoplasmic functions of ATM on autophagy. First, we focused on the functions of ATM in nonselective autophagy within cancer especially those induced by IR, involving the MAPK14 pathway, mTOR pathway, and Beclin1/PI3KIII complexes. These provided a theoretical understanding of tumour radiosensitivity and chemosensitivity. In addition, we emphasized the novel roles of ATM in selective autophagy, including mitophagy, pexophagy, and lipophagy. This review provides new perspectives on the importance of ATM in the diverse field of autophagy, which would provide more information on its role in whole cell dynamics and homeostasis.

Interleukin-18-deficient mice develop dyslipidemia resulting in nonalcoholic fatty liver disease and steatohepatitis

We investigated potential pathophysiological relationships between interleukin 18 (IL-18) and dyslipidemia, nonalcoholic fatty liver disease (NAFLD) or nonalcoholic steatohepatitis (NASH). Compared with Il18(+/+) mice, IL-18 knockout (Il18(-/-)) mice developed hypercholesterolemia and hyper-high-density-lipoprotein-cholesterolemia as well as hypertriglyceridemia as they aged, and these disorders occurred before the manifestation of obesity and might cause secondary NASH. The analyses of molecular mechanisms involved in the onset of dyslipidemia, NAFLD, and NASH in Il18(-/-) mice identified a number of genes associated with these metabolic diseases. In addition, molecules related to circadian rhythm might affect these extracted genes. The intravenous administration of recombinant IL-18 significantly improved dyslipidemia, inhibited the body weight gain of Il18(+/+) mice, and prevented the onset of NASH. The expression of genes related to these dysfunctions was also affected by recombinant IL-18 administration. In conclusion, this study demonstrated the critical function of IL-18 in lipid metabolism and these findings might contribute to the progress of novel treatments for NAFLD or NASH.