Clinical Allergy Research Unit, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden.
PLoS One. 2011;6(7):e21480. doi: 10.1371/journal.pone.0021480. Epub 2011 Jul 22.
Intercellular communication can occur via the release of membrane vesicles. Exosomes are nanovesicles released from the endosomal compartment of cells. Depending on their cell of origin and their cargo they can exert different immunoregulatory functions. Recently, fungi were found to produce extracellular vesicles that can influence host-microbe interactions. The yeast Malassezia sympodialis which belongs to our normal cutaneous microbial flora elicits specific IgE- and T-cell reactivity in approximately 50% of adult patients with atopic eczema (AE). Whether exosomes or other vesicles contribute to the inflammation has not yet been investigated.
To investigate if M. sympodialis can release nanovesicles and whether they or endogenous exosomes can activate PBMC from AE patients sensitized to M. sympodialis.
Extracellular nanovesicles isolated from M. sympodialis, co-cultures of M. sympodialis and dendritic cells, and from plasma of patients with AE and healthy controls (HC) were characterised using flow cytometry, sucrose gradient centrifugation, Western blot and electron microscopy. Their ability to stimulate IL-4 and TNF-alpha responses in autologous CD14, CD34 depleted PBMC was determined using ELISPOT and ELISA, respectively.
We show for the first time that M. sympodialis releases extracellular vesicles carrying allergen. These vesicles can induce IL-4 and TNF-α responses with a significantly higher IL-4 production in patients compared to HC. Exosomes from dendritic cell and M. sympodialis co-cultures induced IL-4 and TNF-α responses in autologous CD14, CD34 depleted PBMC of AE patients and HC while plasma exosomes induced TNF-α but not IL-4 in undepleted PBMC.
Extracellular vesicles from M. sympodialis, dendritic cells and plasma can contribute to cytokine responses in CD14, CD34 depleted and undepleted PBMC of AE patients and HC. These novel observations have implications for understanding host-microbe interactions in the pathogenesis of AE.
细胞间通讯可以通过释放膜泡来实现。外泌体是从细胞的内体区室释放的纳米级囊泡。根据其起源细胞和货物，它们可以发挥不同的免疫调节功能。最近发现真菌产生的细胞外囊泡可以影响宿主-微生物相互作用。属于我们正常皮肤微生物菌群的酵母马拉色菌在大约 50%的特应性皮炎（AE）成年患者中引起特异性 IgE 和 T 细胞反应。外泌体或其他囊泡是否有助于炎症尚未得到研究。
研究马拉色菌是否可以释放纳米囊泡，以及它们或内源性外泌体是否可以激活对马拉色菌敏感的 AE 患者的 PBMC。
使用流式细胞术、蔗糖梯度离心、Western blot 和电子显微镜对从马拉色菌、马拉色菌和树突状细胞共培养物以及 AE 患者和健康对照（HC）的血浆中分离出的细胞外纳米囊泡进行表征。使用 ELISPOT 和 ELISA 分别测定它们在自体 CD14、CD34 耗尽的 PBMC 中刺激 IL-4 和 TNF-α 反应的能力。
我们首次表明，马拉色菌释放携带过敏原的细胞外囊泡。这些囊泡可以诱导 IL-4 和 TNF-α 反应，在患者中产生的 IL-4 明显高于 HC。树突状细胞和马拉色菌共培养物的外泌体诱导 AE 患者和 HC 的自体 CD14、CD34 耗尽的 PBMC 产生 IL-4 和 TNF-α 反应，而血浆外泌体在未耗尽的 PBMC 中诱导 TNF-α而不是 IL-4。
马拉色菌、树突状细胞和血浆的细胞外囊泡可以促进 AE 患者和 HC 的 CD14、CD34 耗尽和未耗尽的 PBMC 中的细胞因子反应。这些新发现对理解 AE 发病机制中的宿主-微生物相互作用具有重要意义。
