Nestin is an intermediate filament protein, which was originally detected in neuroepithelial stem cells. Besides its use as a phenotypic marker of mesenchymal stem cells in the hematopoeitic stem cell niche, the functional interpretation of nestin⁺ cells remains elusive. We investigated the cellular expression of nestin in bone marrow trephine biopsies of MPN patients, following myeloablation at a stage of hypocellularity during early regeneration. Here, nestin is highly expressed in mature osteocytes, arteriolar endothelial and perivascular cells and small capillaries within the bone marrow space, but not in sinusoid lining cells. This is in stark contrast to nestin expression pattern in myeloproliferative neoplasms that show hypercellularity due to oncogenic driver mutations. Here, nestin is expressed exclusively in endothelial cells of arterioles, but not in osteocytes or small capillaries. Thus, the pattern of nestin expression following myeloablation inversely correlates with cellularity in the bone marrow. This nestin expression pattern is mimicking early postnatal transcriptional programming during bone marrow development. We show that nestin expression in osteocytes occurs across different species following transplant and also in bone marrow metastasis.

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清髓后和骨髓转移过程中骨细胞中巢蛋白的表达

巢蛋白是一种中间丝蛋白，最初在神经上皮干细胞中检测到。除了用作造血干细胞生态位中间充质干细胞的表型标记外，nestin ^{+的功能解释}细胞仍然难以捉摸。我们研究了 MPN 患者骨髓环钻活检中巢蛋白的细胞表达，这是在早期再生过程中细胞减少阶段的清髓后。此处，巢蛋白在成熟的骨细胞、小动脉内皮细胞和血管周围细胞以及骨髓腔内的小毛细血管中高度表达，但在血窦衬里细胞中不表达。这与骨髓增生性肿瘤中的巢蛋白表达模式形成鲜明对比，骨髓增生性肿瘤由于致癌驱动突变而显示出细胞过多。在这里，巢蛋白仅在小动脉的内皮细胞中表达，但不在骨细胞或小毛细血管中表达。因此，清髓后巢蛋白的表达模式与骨髓中的细胞结构呈负相关。这种巢蛋白表达模式模仿了骨髓发育过程中的早期出生后转录编程。我们表明骨细胞中的巢蛋白表达发生在移植后的不同物种以及骨髓转移中。