Project description:For placental mammals, the transition from the in utero maternal environment to postnatal life requires the activation of thermogenesis to maintain their core temperature. This is primarily accomplished by induction of uncoupling protein 1 (UCP1) in brown and beige adipocytes, the principal sites for uncoupled respiration. Despite its importance, how placental mammals license their thermogenic adipocytes to participate in postnatal uncoupled respiration is not known. Here, we provide evidence that the 'alarmin' IL-33, a nuclear cytokine that activates type 2 immune responses, licenses brown and beige adipocytes for uncoupled respiration. We find that, in absence of IL-33 or ST2, beige and brown adipocytes develop normally but fail to express an appropriately spliced form of Ucp1 mRNA, resulting in absence of UCP1 protein, and impairment in uncoupled respiration and thermoregulation. Together, these data suggest that IL-33 and ST2 function as a developmental switch to license thermogenesis during the perinatal period.
Project description:Brown and beige fats generate heat via uncoupled respiration to defend against cold, mechanistically, through the action of a network of transcription factors and cofactors. Here we globally profiled long noncoding RNAs (lncRNAs) gene expression during thermogenic adipocyte formation and identified Brown fat lncRNA 1 (Blnc1) as a novel nuclear lncRNA that promotes brown and beige adipocyte differentiation and function by forming a feedforward regulatory loop with EBF2 to drive adipogenesis toward thermogenic phenotype. LncRNAs expression were measured in BAT and WAT from mice injected saline/CL and during brown adipocyte differentiation with two replicates using Arraystar Mouse LncRNA microarray V2.0
Project description:The activation of brown/beige adipose tissue (BAT) metabolism and the induction of uncoupling protein-1 (UCP1) expression are essential for BAT-based strategies to improve metabolic homeostasis. Adrenergic signaling is viewed as a key regulator of thermogenesis and UCP1-expression in BAT, while also operating as a potent contractile stimulator in muscle. The muscle-like gene expression patterns of UCP1+ adipocytes have previously been utilized as tissue specific markers, but have not been attributed with any functional role. Here, we demonstrate that BAT utilizes actomyosin machinery to generate tensional responses following adrenergic stimulation, similar to muscle tissues. We show that activation of actomyosin mechanics are critical for the acute induction of oxidative metabolism and uncoupled respiration in UCP1+ adipocytes. Additionally, actomyosin-mediated elasticity regulates mechanosensitive transcriptional co-activators, YAP/TAZ, that facilitate the thermogenic capacity of adipocytes. These unappreciated signaling and mechanical mechanisms may inform future strategies to promote the expansion and activation of brown/beige adipocytes.
Project description:Brown and beige fats generate heat via uncoupled respiration to defend against cold, mechanistically, through the action of a network of transcription factors and cofactors. Here we globally profiled long noncoding RNAs (lncRNAs) gene expression during thermogenic adipocyte formation and identified Brown fat lncRNA 1 (Blnc1) as a novel nuclear lncRNA that promotes brown and beige adipocyte differentiation and function by forming a feedforward regulatory loop with EBF2 to drive adipogenesis toward thermogenic phenotype.
Project description:Brown adipose tissue (BAT) generates heat via uncoupled respiration, providing mammals with an evolutionary defense against environmental cold. Although the molecular pathways by which cold activates brown adipocytes are well understood, little is known about how BAT maintains its thermogenic capacity during adaptation to environmental warmth. Here, we identify the transcriptional repressor BCL6 as the switch for maintaining brown adipocyte cellular identity under warm conditions. Mice lacking BCL6 in their brown adipocytes display normal thermogenic responses when housed in a cool environment, but fail to maintain thermogenic fitness when housed under warm conditions. In a temperature-dependent manner, BCL6 suppresses apoptosis, fatty acid storage, and coupled respiration to maintain thermogenic competence in brown adipocytes. Enhancer analysis revealed that BCL6 reinforces brown-specific while opposing white-specific enhancers to maintain cellular identity. Thus, unlike other regulators, BCL6 is dispensable for differentiation and activation of brown adipocytes, but specifically required for their maintenance in warmth.
Project description:Beige and brown adipocytes generate heat in response to reductions in ambient temperature. When warmed, both beige and brown adipocytes exhibit morphological ‘whitening’, but it is unknown whether or to what extent this represents a true shift in cellular identity. Using cell type-specific profiling in vivo, we uncover a unique paradigm of temperature-dependent epigenomic plasticity of beige, but not brown, adipocytes, with conversion from a brown to a white chromatin state. Despite this profound shift in cellular identity, warm whitened beige adipocytes retain an epigenomic memory of prior cold exposure defined by an array of poised enhancers that prime thermogenic genes for rapid response during a second bout of cold exposure. We further show that a transcriptional cascade involving the glucocorticoid receptor and Zfp423 can drive warm-induced whitening of beige adipocytes. These studies identify the epigenomic and transcriptional bases of an extraordinary example of cellular plasticity in response to environmental signals.
Project description:The effects of IL-33 on ST2+ Treg cells were not studied thouroughly. We FACS-sorted in vitro expanded ST2+ Treg cells from C57BL/6 Foxp3-IRES-mRFP (B6 FIR) mice. We next used RNA-seq techonology to define how recombinant IL-33 (rIL-33) may impact mouse Treg by to assessing the transcriptome of IL-33-stimulated ST2+ Treg cells compared to that of untreated ST2+ Treg cells. Our data revealed that ST2+ Treg stimulated with rIL-33 for 6 hours exhibited increased expression of Il10 and Il13 compared to unstimulated ST2+ Treg cells.
Project description:Identification of Proteins and smORF-encoded microproteins in the secretomes of Brown Adipocytes and subcutaneous white adipocytes differentiated to both a white and beige phenotype.
Project description:Identification of Proteins and smORF-encoded microproteins in the proteomes of Brown Adipocytes and subcutaneous white adipocytes differentiated to both a white and beige phenotype.
Project description:ST2 heterodimerizes with IL-1RAcp to form the receptor for IL-33, which is primarily associated with allergic inflammation by inducing Th2 responses. Recently, however, IL-33 was found to be expressed in the central nervous system and in retinal Muller cells which imply functions, as yet undescribed, beyond Th2 mediated inflammation. Muller cells support the health of the retina and photoreceptors and are also involved in inflammation in retinal degeneration. It is not known how IL-33/ST2 functions in this capacity. We recently found that ST2 ko mice are protected from CLE-induced photoreceptor loss, implying a detrimental effect of IL33/ST2 in CLE. We wish to perform microarray analysis using WT and ST2 KO mice in CLE model to better understand the mechanism by which IL-33/ST2 regulates retinal degeneration.