Investigation of Beige Fat Biology and Metabolism Using the CRISPR SunTag-p65-HSF1 Activation System.

Clustered regularly interspaced short palindromic repeats (CRISPR) technology has prompted a revolution in biology, and recent tools have been applied far beyond the originally described gene editing. The CRISPR activation (CRISPRa) system combines the catalytically inactive Cas9 (dCas9) protein with distinct transcription modules to induce endogenous gene expression. SunTag-p65-HSF1 (SPH) is a recently developed CRISPRa technology that combines components of synergistic activation mediators (SAMs) with the SunTag activators. This system allows the overexpression of single or multiple genes by designing a customized single-guide RNA (sgRNA). In this study, a previously developed SPH mouse was used to generate a conditional mouse expressing SPH in adipocytes (adiponectin Cre lineage), named AdipoSPH. To induce a white-to-beige fat (browning) phenotype, an adeno-associated virus (AAV) carrying sgRNA targeting the endogenous Prdm16 gene (a well-established transcription factor related to brown and beige fat development) was injected into the inguinal white adipose tissue (iWAT). This mouse model induced the expression of endogenous Prdm16 and activated the thermogenic gene program. Moreover, in vitro SPH-induced Prdm16 overexpression enhanced the oxygen consumption of beige adipocytes, phenocopying the results of a previous Prdm16 transgenic mouse model. Thus, this protocol describes a versatile, cost-effective, and time-effective mouse model for investigating adipose tissue biology.

BCAA catabolism in brown fat controls energy homeostasis through SLC25A44.

Branched-chain amino acid (BCAA; valine, leucine and isoleucine) supplementation is often beneficial to energy expenditure; however, increased circulating levels of BCAA are linked to obesity and diabetes. The mechanisms of this paradox remain unclear. Here we report that, on cold exposure, brown adipose tissue (BAT) actively utilizes BCAA in the mitochondria for thermogenesis and promotes systemic BCAA clearance in mice and humans. In turn, a BAT-specific defect in BCAA catabolism attenuates systemic BCAA clearance, BAT fuel oxidation and thermogenesis, leading to diet-induced obesity and glucose intolerance. Mechanistically, active BCAA catabolism in BAT is mediated by SLC25A44, which transports BCAAs into mitochondria. Our results suggest that BAT serves as a key metabolic filter that controls BCAA clearance via SLC25A44, thereby contributing to the improvement of metabolic health.

Thermal stress induces glycolytic beige fat formation via a myogenic state.

Environmental cues profoundly affect cellular plasticity in multicellular organisms. For instance, exercise promotes a glycolytic-to-oxidative fibre-type switch in skeletal muscle, and cold acclimation induces beige adipocyte biogenesis in adipose tissue. However, the molecular mechanisms by which physiological or pathological cues evoke developmental plasticity remain incompletely understood. Here we report a type of beige adipocyte that has a critical role in chronic cold adaptation in the absence of ß-adrenergic receptor signalling. This beige fat is distinct from conventional beige fat with respect to developmental origin and regulation, and displays enhanced glucose oxidation. We therefore refer to it as glycolytic beige fat. Mechanistically, we identify GA-binding protein α as a regulator of glycolytic beige adipocyte differentiation through a myogenic intermediate. Our study reveals a non-canonical adaptive mechanism by which thermal stress induces progenitor cell plasticity and recruits a distinct form of thermogenic cell that is required for energy homeostasis and survival.

Multifaceted Roles of Beige Fat in Energy Homeostasis Beyond UCP1.

Beige adipocytes are an inducible form of thermogenic adipose cells that emerge within the white adipose tissue in response to a variety of environmental stimuli, such as chronic cold acclimation. Similar to brown adipocytes that reside in brown adipose tissue depots, beige adipocytes are also thermogenic; however, beige adipocytes possess unique, distinguishing characteristics in their developmental regulation and biological function. This review highlights recent advances in our understanding of beige adipocytes, focusing on the diverse roles of beige fat in the regulation of energy homeostasis that are independent of the canonical thermogenic pathway via uncoupling protein 1.

Burning Fat and Building Bone by FSH Blockade.

The rise of follicle-stimulating hormone (FSH) is a hallmark of menopause associated with osteoporosis and visceral adiposity. In Nature, Zaidi and colleagues (Liu et al., 2017) report that blocking FSH action reduces body fat by promoting brown/beige fat thermogenesis, potentially providing a new intervention for the treatment of menopause-related metabolic diseases.

Atividade física na infância e na adolescência promove efeitos benéficos na saúde de adultos / Health-promoting efects of early physical activity in adulthood

Fundamentos: A relação da prática de atividades física na infância e na adolescência com a ocorrência de doenças na idade adulta não tem sido bastante estudada. Objetivos: Analisar a associação entre dislipidemia na idade adulta, atividade física prévia e outros fatores de risco. Métodos: Estudados 829 adultos (idade > ou igual 18 anos [324 homens e 505 mulheres]), selecionados de maneira aleatória em três cidades do Estado de São Paulo. A presença de dislipidemia foi autorreferida (diagnóstico médico prévio obrigatório), bem como: peso corporal, estatura e escolaridade. Resultados: Dislipidemia foi reportada por 11,7 por cento (IC95 por cento=9,5 por cento-14 por cento) dos avaliados e associada com: sexo feminino (p=0,042), residir na capital (p=0,009), menor escolaridade (p=0,001),estado nutricional (p=0,001), maior idade (p=0,002), atividade física prévia (p=0,001) e atual (p=0,001)e atual (p=0,026). Atividade física...