Department of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.
Division of Molecular Oncology, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.
Clin Exp Nephrol. 2024 Jul;28(7):617-628. doi: 10.1007/s10157-024-02464-z. Epub 2024 Mar 4.
Extracellular vesicles (EVs) have received considerable attention as ideal biomarkers for kidney diseases. Most reports have focused on urinary EVs, that are mainly derived from the cells in the urinary tract. However, the detection and the application of kidney-derived EVs in plasma remains uncertain.
We examined the kidney-derived small EVs (sEVs) in plasma that were supposedly released from renal mesangial and glomerular endothelial cells, using clinical samples from healthy controls and patients with kidney transplants. Plasma from healthy controls underwent ultracentrifugation, followed by on-bead flow cytometry, targeting α8 integrin, an antigen-specific to mesangial cells. To confirm the presence of kidney-derived sEVs in peripheral blood, plasma from ABO-incompatible kidney transplant recipients was ultracentrifuged, followed by western blotting for donor blood type antigens.
Immunohistochemistry and immunoelectron microscopy confirmed α8 integrin expression in kidney mesangial cells and their sEVs. The CD9-α8 integrin double-positive sEVs were successfully detected using on-bead flow cytometry. Western blot analysis further revealed transplanted kidney-derived sEVs containing blood type B antigens in non-blood type B recipients, who had received kidneys from blood type B donors. Notably, a patient experiencing graft kidney loss exhibited diminished signals of sEVs containing donor blood type antigens.
Our findings demonstrate the potential usefulness of kidney-derived sEVs in plasma in future research for kidney diseases.
细胞外囊泡（EVs）作为肾脏疾病的理想生物标志物受到了广泛关注。大多数报告都集中在尿源性 EVs 上，这些 EVs 主要来源于泌尿道细胞。然而，肾源性 EVs 在血浆中的检测和应用仍不确定。
我们使用来自健康对照者和肾移植患者的临床样本，检测了来自肾小球内皮细胞和肾系膜细胞的、推测在血浆中释放的肾源性小细胞外囊泡（sEVs）。对健康对照者的血浆进行超速离心，然后进行基于珠子的流式细胞术，以靶向 α8 整合素，这是一种特异地针对系膜细胞的抗原。为了确认外周血中是否存在肾源性 sEVs，对 ABO 不相容肾移植受者的血浆进行超速离心，然后进行供体血型抗原的 Western blot 分析。
免疫组织化学和免疫电子显微镜证实了 α8 整合素在肾系膜细胞及其 sEVs 中的表达。使用基于珠子的流式细胞术成功检测到 CD9-α8 整合素双阳性 sEVs。Western blot 分析进一步显示，在接受来自血型 B 供体的肾脏的非血型 B 受者的血浆中存在含有血型 B 抗原的移植肾源性 sEVs。值得注意的是，一位经历移植物肾丢失的患者表现出含有供体血型抗原的 sEVs 信号减弱。
我们的研究结果表明，血浆中的肾源性 sEVs 在未来的肾脏疾病研究中具有潜在的应用价值。
