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Thoracic aortic perivascular adipose tissue (PVAT) is an adipose organ exhibiting similarities to brown adipose tissue (BAT), including cellular morphology and thermogenic gene expression. However, whether the PVAT phenotype is indistinguishable from the BAT phenotype in physiological vasculature remains unclear. We demonstrated that PVAT is distinguishable from classical BAT, given its specific vessel-tone-controlling function. Activating transcription factor 3 (ATF3) is a key factor in hypertension. Compared with wild-type mice, ATF3-deficient (ATF3 -/- ) mice fed a high-fat diet exhibited elevated mean arterial pressure, increased monocyte chemoattractant protein-1 expression and hypertrophy, plus abnormal fatty tissue accumulation in the thoracic aortic PVAT, and enhanced vascular wall tension and vasoconstrictive responses of potassium chloride, U46619, and norepinephrine in isolated aortic rings, which were restored after administration of adeno-associated ATF3 vector. We suggest that PVAT, not BAT, modulates obesity-related vascular dysfunction. ATF3 within PVAT could provide new insights into the pathophysiology of obesity-related cardiovascular diseases., Competing Interests: The authors declare no competing interests., (© 2022 The Authors.)

Certain vertebrates such as salamanders and zebrafish are able to regenerate complex tissues (e.g., limbs and fins) with remarkable fidelity. However, how positional information of the missing structure is recalled by appendage stump cells has puzzled researchers for centuries. Here, we report that sizing information for adult zebrafish tailfins is encoded within proliferating blastema cells during a critical period of regeneration. Using a chemical mutagenesis screen, we identified a temperature-sensitive allele of the gene encoding DNA polymerase alpha subunit 2 (pola2) that disrupts fin regeneration in zebrafish. Temperature shift assays revealed a 48-h window of regeneration, during which positional identities could be disrupted in pola2 mutants, leading to regeneration of miniaturized appendages. These fins retained memory of the new size in subsequent rounds of amputation and regeneration. Similar effects were observed upon transient genetic or pharmacological disruption of progenitor cell proliferation after plucking of zebrafish scales or head or tail amputation in amphioxus and annelids. Our results provide evidence that positional information in regenerating tissues is not hardwired but malleable, based on regulatory mechanisms that appear to be evolutionarily conserved across distantly related phyla., (Copyright © 2019 Elsevier Ltd. All rights reserved.)