Project description:Brown adipose tissue (BAT) is a major site of nonshivering thermogenesis (NST) in mammals and might play an important role in human obesity and energy homeostasis. Recent single-cell/nucleus RNA-sequencing studies have revealed heterogeneity in thermogenesis among brown adipocytes, such as the findings of low thermogenesis and regulated thermogenesis in brown adipocytes. Activating and enhancing function adipocytes (BAC) has acquired attention as a possible therapeutic intervention for metabolic diseases. Nuclear factor-erythroid 2-related factor 1 (NFE2L1, also known as Nrf1), a CNC-bZIP protein, is a master regulator of multiple cellular functions and responds to various stress in many cells and tissues. NFE2L1 acts as a guardian role in BAC function providing increased proteometabolic quality control for adapting to cold or obesity. Our previous studies demonstrated that NFE2L1-dependent lipolytic activity is crucial for white adipose tissue (WAT) plasticity and lipid homeostasis. To further clarify the role of NFE2L1 in adipocytes, we focused on the phenotype and gene expression profiling of BAT in adipocyte-specific Nfe2l1-knockout [Nfe2l1(f)-KO] mice. We found that deletion of Nfe2l1 decreased core body temperature and cold intolerance under cold exposure. Compared with floxed mice, the BAT of Nfe2l1(f)-KO mice expressed substantially lower levels of many genes related to lipolysis, thermogenesis, oxidative capacity of mitochondria, cellular respiration while higher genes related to inflammation, pyroptosis. By snRNA-seq, we found that Nfe2l1-knockout resulted in increased antigen processing and presentation (APP), necroptosis and NOD-like receptor signal pathway (NOD) signaling pathways in most subpopulations of BAC, with devastating effects on a normal subpopulation of BAC with low thermogenesis and high necroptosis genes expression. Absent of Nfe2l1 impairs the function of BAC, causing a morphological “whitening” phenotype with adipocyte hypertrophy and severe inflammation. Moreover, the adipose inflammation and pyroptosis in Nfe2l1(f)-KO mice could be mitigated by cold exposure or β3-agonist treatment. These findings provided a deeper insight into the function of NFE2L1 in the metabolic programming of brown adipocytes.

Project description:Members of the Nuclear mRNA Export Factor (NXF) family are implicated in nuclear export and/or cytoplasmic transport of mRNAs in eukaryotic cells. We previously proposed NXF5 to be involved in cognitive development and aimed to study its functional role further using a mouse model. The syntenic region of the human Xcen-GLA-NXF5-NXF2-NXF3-BEX4-Xqter in the mouse is Xcen-Gla-Nxf2-Nxf7-Nxf3-Bex4-Xqter strongly indicating that mouse Nxf2 is the homolog of human NXF5. However, our functional analyses demonstrated that mouse Nxf7 is actually the functional homolog of NXF5. Both orthologs are expressed in brain, although at low levels, show predominant cytoplasmic localization, and present a granular staining in neuronal dendrites, all indicative for a role in cytoplasmic mRNA transport or metabolism. The mouse and human Nxf2/NXF2 proteins on the other hand, show highest expression in testis, and mostly nuclear staining with incorporation in the nuclear membrane, suggesting a predominant role in nuclear mRNA export. Based on these findings we generated an Nxf7 knockout mouse, which was viable and fertile and no gross anatomical changes or morphological brain abnormalities were detected. Detailed behavioral analysis demonstrated that Nxf7 KO mice displayed a deficit in hippocampus-dependent spatial learning and memory. At the cellular level, this was accompanied by impaired hippocampal long-term potentiation, but normal long-term depression, suggesting a severe functional imbalance in NMDA-dependent synaptic plasticity. In conclusion, the present findings indicate that NXF5, and its murine ortholog Nxf7, play a crucial role in neurocognitive (memory) functions, and explain why its deletion leads to intellectual disability. Two male wild type (WT1 and WT2) and two Nxf7 knockout (KO1 and KO2) mice were used in each hybridization experiment (hippocampus or cortex). A loop-design hybridization scheme (WT1/KO1, KO1/WT2, WT2/KO2 and KO2/WT1) was performed for each experiment so as to have each sample labeled once with Cy5 and once with Cy3, and hybridised to both samples of the other genotype (WT or KO). Hybridization was done on Agilent Mouse Whole Genome arrays according to the manufacturerM-bM-^@M-^Ys procedures.

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Impact of NFE2L1 knockout on gene expression

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