Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): BHF Programme Grant (RG/16/14/32397) VASCage-Research Center on Vascular Ageing and Stroke (No. 868624) Background While canonical adipose tissue (AT) depots have been extensively characterised in health and disease, comparatively little is known about the pathological changes affecting the perivascular AT’s (PVAT) physiology during obesity. Purpose The aim of this study was to study the impact of obesity on the secretory activity of the murine PVAT. Methods We exploited proteomics to profile the secretome of peri-aortic and canonical AT depots in wild-type (wt) and obese (ob/ob) mice. In parallel, fat tissues were processed for biochemical and histological analysis and mechanistical experiments were performed in vitro on primary neuronal cultures. Results Proteomics on ATs conditioned media from wt mice revealed that each fat depot displays a unique secretory profile. The enrichment of neuronal cell-adhesion molecules detected in PVAT secretomes reflected a higher content of intra-parenchymal sympathetic projections compared to non-perivascular ATs. A significant decrease of the same neuronal proteins in PVAT conditioned media from ob/ob mice was found to be associated with a substantial reduction of the perivascular sympathetic innervation. Intriguingly, a similar decrease of sympathetic markers was detected in the epicardial AT from obese patients. Mechanistically, the conditioned media from ob/ob AT explants was found to exert a deleterious effect on the axons of primary sympathetic neurons in vitro, indicating that this neuropathy is due to local alterations of the PVAT secretome that detrimentally impact on the embedded sympathetic neurites. Among proteins significantly down-regulated in the secretomes of ob/ob PVAT samples, neuronal growth regulator 1 (Negr1) was found to promote axonal elongation and branching on sympathetic neurons in vitro. Administration of recombinant Negr1 also partially restored the neurotrophic effect of ob/ob AT secretomes on sympathetic axons both in vitro and in vivo. Conclusions Obesity-related alterations in the secretome of PVAT severely affect the homeostasis of the perivascular environment, leading to a loss of perivascular sympathetic innervation. A novel neurotrophic role is unveiled for Negr1, whose locus has been associated with human obesity.

中文翻译：

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肥胖血管周围脂肪组织的比较分泌组分析显示脂肪-神经元串扰受损

资金致谢 资金来源类型：基金会。主要资金来源：BHF 计划拨款 (RG/16/14/32397) VASCage-血管衰老和中风研究中心（编号 868624） , 关于肥胖期间影响血管周围 AT (PVAT) 生理的病理变化知之甚少。目的 本研究的目的是研究肥胖对小鼠 PVAT 分泌活动的影响。方法 我们利用蛋白质组学分析野生型 (wt) 和肥胖 (ob/ob) 小鼠的主动脉周围和典型 AT 贮库的分泌组。同时，对脂肪组织进行生化和组织学分析，并在体外对原代神经元培养物进行机械实验。结果 来自 wt 小鼠的 ATs 条件培养基的蛋白质组学显示每个脂肪库都显示出独特的分泌谱。与非血管周围的 AT 相比，在 PVAT 分泌物中检测到的神经元细胞粘附分子的富集反映了实质内交感神经投射的更高含量。发现来自 ob/ob 小鼠的 PVAT 条件培养基中相同神经元蛋白的显着减少与血管周围交感神经支配的显着减少有关。有趣的是，在肥胖患者的心外膜 AT 中检测到类似的交感神经标志物减少。从机制上讲，发现来自 ob/ob AT 外植体的条件培养基在体外对初级交感神经元的轴突产生有害影响，表明这种神经病变是由于 PVAT 分泌组的局部改变对嵌入的交感神经突产生不利影响。在 ob/ob PVAT 样本的分泌组中显着下调的蛋白质中，发现神经元生长调节剂 1 (Negr1) 在体外促进交感神经元的轴突伸长和分支。重组 Negr1 的给药也部分恢复了 ob/ob AT 分泌组在体外和体内对交感神经轴突的神经营养作用。结论 肥胖相关的 PVAT 分泌组改变严重影响血管周围环境的稳态，导致血管周围交感神经支配的丧失。Negr1 揭示了一种新的神经营养作用，其基因座与人类肥胖有关。在 ob/ob PVAT 样本的分泌组中显着下调的蛋白质中，发现神经元生长调节剂 1 (Negr1) 在体外促进交感神经元的轴突伸长和分支。重组 Negr1 的给药也部分恢复了 ob/ob AT 分泌组在体外和体内对交感神经轴突的神经营养作用。结论 肥胖相关的 PVAT 分泌组改变严重影响血管周围环境的稳态，导致血管周围交感神经支配的丧失。Negr1 揭示了一种新的神经营养作用，其基因座与人类肥胖有关。在 ob/ob PVAT 样本的分泌组中显着下调的蛋白质中，发现神经元生长调节剂 1 (Negr1) 在体外促进交感神经元的轴突伸长和分支。重组 Negr1 的给药也部分恢复了 ob/ob AT 分泌组在体外和体内对交感神经轴突的神经营养作用。结论 肥胖相关的 PVAT 分泌组改变严重影响血管周围环境的稳态，导致血管周围交感神经支配的丧失。Negr1 揭示了一种新的神经营养作用，其基因座与人类肥胖有关。重组 Negr1 的给药也部分恢复了 ob/ob AT 分泌组在体外和体内对交感神经轴突的神经营养作用。结论 肥胖相关的 PVAT 分泌组改变严重影响血管周围环境的稳态，导致血管周围交感神经支配的丧失。Negr1 揭示了一种新的神经营养作用，其基因座与人类肥胖有关。重组 Negr1 的给药也部分恢复了 ob/ob AT 分泌组在体外和体内对交感神经轴突的神经营养作用。结论 肥胖相关的 PVAT 分泌组改变严重影响血管周围环境的稳态，导致血管周围交感神经支配的丧失。Negr1 揭示了一种新的神经营养作用，其基因座与人类肥胖有关。