Pawar Aditya S, Eirin Alfonso, Tang Hui, Zhu Xiang-Yang, Lerman Amir, Lerman Lilach O
Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, United States.
Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, United States.
Cytokine. 2020 Mar 30;130:155080. doi: 10.1016/j.cyto.2020.155080.
Mesenchymal stem cells (MSCs) have endogenous reparative properties, and may constitute an exogenous therapeutic intervention in patients with chronic kidney disease. The microenvironment of metabolic syndrome (MetS) induces fat inflammation, with abundant expression of tumor necrosis factor (TNF)-α. MetS may also alter the content of adipose tissue-derived MSCs, and we hypothesized that the inflammatory profile of MetS manifests via upregulating MSC mRNAs and proteins of the TNF-α pathway.
Domestic pigs were fed a 16-week Lean or MetS diet (n = 4 each). MSCs were harvested from abdominal subcutaneous fat, and their extracellular vesicles (EVs) isolated. Expression profiles of mRNAs and proteins in MSCs and EVs were obtained by high-throughput sequencing and proteomics. Nuclear translocation of the pro-inflammatory transcription factor (NF)-kB was evaluated in MSC and in pig renal tubular cells (TEC) co-incubated with EVs.
We found 13 mRNAs and 4 proteins in the TNF-α pathway upregulated in MetS- vs. Lean-MSCs (fold-change > 1.4, p < 0.05), mostly via TNF-α receptor-1 (TNF-R1) signaling. Three mRNAs were upregulated in MetS-EVs. MetS-MSCs, as well as TECs co-incubated with MetS-EVs, showed increased nuclear translocation of NF-kB. Using qPCR, JUNB, MAP2K7 and TRAF2 genes followed the same direction of RNA-sequencing findings.
MetS upregulates the TNF-α transcriptome and proteome in swine adipose tissue-derived MSCs, which are partly transmitted to their EV progeny, and are associated with activation of NF-kB in target cells. Hence, the MetS milieu may affect the profile of endogenous MSCs and their paracrine vectors and limit their use as an exogenous regenerative therapy. Anti-inflammatory strategies targeting the TNF-α pathway might be a novel strategy to restore MSC phenotype, and in turn function.
间充质干细胞（MSC）具有内源性修复特性，可能成为慢性肾脏病患者的一种外源性治疗干预手段。代谢综合征（MetS）的微环境会引发脂肪炎症，肿瘤坏死因子（TNF）-α表达丰富。MetS还可能改变脂肪组织来源的MSC的含量，我们推测MetS的炎症特征是通过上调TNF-α信号通路的MSC mRNA和蛋白质来体现的。
给家猪喂食16周的瘦肉型或MetS饮食（每组n = 4）。从腹部皮下脂肪中采集MSC，并分离其细胞外囊泡（EV）。通过高通量测序和蛋白质组学获得MSC和EV中mRNA和蛋白质的表达谱。在与EV共同孵育的MSC和猪肾小管细胞（TEC）中评估促炎转录因子（NF）-kB的核转位。
我们发现，与瘦肉型MSC相比，MetS-MSC中TNF-α信号通路中有13种mRNA和4种蛋白质上调（变化倍数> 1.4，p < 0.05），主要通过TNF-α受体-1（TNF-R1）信号传导。MetS-EV中有3种mRNA上调。MetS-MSC以及与MetS-EV共同孵育的TEC显示NF-kB的核转位增加。使用qPCR，JUNB、MAP2K7和TRAF2基因的变化趋势与RNA测序结果一致。
MetS上调猪脂肪组织来源的MSC中的TNF-α转录组和蛋白质组，其中部分传递给其EV后代，并与靶细胞中NF-kB的激活有关。因此，MetS环境可能会影响内源性MSC及其旁分泌载体的特征，并限制它们作为外源性再生疗法的应用。针对TNF-α信号通路的抗炎策略可能是恢复MSC表型进而恢复其功能的一种新策略。
