Institute for Neuroscience of Castile and Leon, INCyL, Universidad de Salamanca, C/Pintor Fernando Gallego 1, 37007, Salamanca, Spain.
Institute of Biomedical Research of Salamanca, IBSAL, Salamanca, Spain.
J Neuroinflammation. 2024 Feb 14;21(1):49. doi: 10.1186/s12974-023-03000-8.
Myeloid-derived suppressor cells (MDSCs) constitute a recently discovered bone-marrow-derived cell type useful for dealing with neuroinflammatory disorders. However, these cells are only formed during inflammatory conditions from immature myeloid cells (IMCs) that acquire immunosuppressive activity, thus being commonly gathered from diseased animals. Then, to obtain a more clinically feasible source, we characterized IMCs directly derived from healthy bone marrow and proved their potential immunosuppressive activity under pathological conditions in vitro. We then explored their neuroprotective potential in a model of human cerebellar ataxia, the Purkinje Cell Degeneration (PCD) mouse, as it displays a well-defined neurodegenerative and neuroinflammatory process that can be also aggravated by invasive surgeries.
IMCs were obtained from healthy bone marrow and co-cultured with activated T cells. The proliferation and apoptotic rate of the later were analyzed with Tag-it Violet. For in vivo studies, IMCs were transplanted by stereotactic surgery into the cerebellum of PCD mice. We also used sham-operated animals as controls of the surgical effects, as well as their untreated counterparts. Motor behavior of mice was assessed by rotarod test. The Purkinje cell density was measured by immunohistochemistry and cell death assessed with the TUNEL technique. We also analyzed the microglial phenotype by immunofluorescence and the expression pattern of inflammation-related genes by qPCR. Parametric tests were applied depending on the specific experiment: one or two way ANOVA and Student's T test.
IMCs were proven to effectively acquire immunosuppressive activity under pathological conditions in vitro, thus acting as MDSCs. Concerning in vivo studios, sham-operated PCD mice suffered detrimental effects in motor coordination, Purkinje cell survival and microglial activation. After intracranial administration of IMCs into the cerebellum of PCD mice, no special benefits were detected in the transplanted animals when compared to untreated mice. Nonetheless, this transplant almost completely prevented the impairments caused by the surgery in PCD mice, probably by the modulation of the inflammatory patterns.
Our work comprise two main translational findings: (1) IMCs can be directly used as they behave as MDSCs under pathological conditions, thus avoiding their gathering from diseased subjects; (2) IMCs are promising adjuvants when performing neurosurgery.
髓源性抑制细胞（MDSCs）是一种新发现的骨髓来源细胞类型，可用于治疗神经炎症性疾病。然而，这些细胞仅在炎症条件下由获得免疫抑制活性的未成熟髓样细胞（IMCs）形成，因此通常从患病动物中收集。为了获得更具临床可行性的来源，我们直接从健康骨髓中鉴定 IMCs，并在体外证实了它们在病理条件下的潜在免疫抑制活性。然后，我们在人类小脑共济失调模型——浦肯野细胞退化（PCD）小鼠中探索了它们的神经保护潜力，因为它表现出明确的神经退行性和神经炎症过程，并且可以通过侵入性手术加重。
从健康骨髓中获得 IMCs，并与激活的 T 细胞共培养。使用 Tag-it Violet 分析后者的增殖和凋亡率。在体内研究中，通过立体定向手术将 IMCs移植到 PCD 小鼠的小脑。我们还使用假手术动物作为手术效果的对照，以及未经处理的对照动物。通过转棒试验评估小鼠的运动行为。通过免疫组织化学测量浦肯野细胞密度，并通过 TUNEL 技术评估细胞死亡。我们还通过免疫荧光分析小胶质细胞表型，并通过 qPCR 分析炎症相关基因的表达模式。根据特定实验应用参数检验：单向或双向 ANOVA 和学生 T 检验。
IMCs 被证明在体外病理条件下能有效地获得免疫抑制活性，从而发挥 MDSCs 的作用。关于体内研究，假手术 PCD 小鼠在运动协调、浦肯野细胞存活和小胶质细胞激活方面受到不利影响。将 IMCs 颅内给药到 PCD 小鼠的小脑后，与未经处理的小鼠相比，移植动物没有检测到特殊益处。然而，这种移植几乎完全预防了 PCD 小鼠手术引起的损伤，可能是通过调节炎症模式。
我们的工作包括两个主要的转化发现：（1）IMCs 可以直接用作 MDSCs，因为它们在病理条件下表现出 MDSCs 的特性，从而避免从患病患者中收集；（2）IMCs 是神经外科手术的有前途的佐剂。
