Bose Raj, Posada-Pérez Mercedes, Karvela Eleni, Skandik Martin, Keane Lily, Falk Anna, Spulber Stefan, Joseph Bertrand, Ceccatelli Sandra
Department of Neuroscience, Karolinska Institutet, 17177 Stockholm, Sweden; Center for Neuromusculoskeletal Restorative Medicine, Shui On Centre, Wan Chai, Hong Kong.
Institute of Environmental Medicine, Toxicology Unit, Karolinska Institutet, 17177 Stockholm, Sweden; Center for Neuromusculoskeletal Restorative Medicine, Shui On Centre, Wan Chai, Hong Kong.
Brain Behav Immun. 2025 Jan;123:28-42. doi: 10.1016/j.bbi.2024.09.001. Epub 2024 Sep 5.
Autism spectrum disorder (ASD) is a set of heterogeneous neurodevelopmental conditions, with a highly diverse genetic hereditary component, including altered neuronal circuits, that has an impact on communication skills and behaviours of the affected individuals. Beside the recognised role of neuronal alterations, perturbations of microglia and the associated neuroinflammatory processes have emerged as credible contributors to aetiology and physiopathology of ASD. Mutations in NRXN1, a member of the neurexin family of cell-surface receptors that bind neuroligin, have been associated to ASD. NRXN1 is known to be expressed by neurons where it facilitates synaptic contacts, but it has also been identified in glial cells including microglia. Asserting the impact of ASD-related genes on neuronal versus microglia functions has been challenging. Here, we present an ASD subject-derived induced pluripotent stem cells (iPSC)-based in vitro system to characterise the effects of the ASD-associated NRXN1 gene deletion on neurons and microglia, as well as on the ability of microglia to support neuronal circuit formation and function. Using this approach, we demonstrated that NRXN1 deletion, impacting on the expression of the alpha isoform (NRXN1α), in microglia leads to microglial alterations and release of IL6, a pro-inflammatory interleukin associated with ASD. Moreover, microglia bearing the NRXN1α-deletion, lost the ability to support the formation of functional neuronal networks. The use of recombinant IL6 protein on control microglia-neuron co-cultures or neutralizing antibody to IL6 on their NRXN1α-deficient counterparts, supported a direct contribution of IL6 to the observed neuronal phenotype. Altogether, our data suggest that, in addition to neurons, microglia are also negatively affected by NRXN1α-deletion, and this significantly contributes to the observed neuronal circuit aberrations.
自闭症谱系障碍（ASD）是一组异质性神经发育疾病，具有高度多样的遗传遗传成分，包括改变的神经回路，会影响受影响个体的沟通技能和行为。除了已认识到的神经元改变的作用外，小胶质细胞的扰动和相关的神经炎症过程已成为ASD病因学和病理生理学的可信因素。神经连接蛋白1（NRXN1）是细胞表面受体神经连接蛋白家族的成员，其突变与ASD有关。已知NRXN1由神经元表达，在那里它促进突触接触，但也已在包括小胶质细胞在内的胶质细胞中被鉴定出来。确定与ASD相关的基因对神经元与小胶质细胞功能的影响一直具有挑战性。在这里，我们提出了一种基于自闭症谱系障碍患者来源的诱导多能干细胞（iPSC）的体外系统，以表征与ASD相关的NRXN1基因缺失对神经元和小胶质细胞的影响，以及小胶质细胞支持神经元回路形成和功能的能力。使用这种方法，我们证明NRXN1的缺失，影响小胶质细胞中α异构体（NRXN1α）的表达，导致小胶质细胞改变和白细胞介素6（IL6）的释放，IL6是一种与ASD相关的促炎白细胞介素。此外，携带NRXN1α缺失的小胶质细胞失去了支持功能性神经元网络形成的能力。在对照小胶质细胞-神经元共培养物中使用重组IL6蛋白或在其NRXN1α缺陷对应物中使用IL6中和抗体，支持IL6对观察到的神经元表型有直接作用。总之，我们的数据表明，除了神经元外，小胶质细胞也受到NRXN1α缺失的负面影响，这显著导致了观察到的神经元回路异常。
