Qu Lintao
Department of Anesthesiology, Yale University School of Medicine, New Haven, CT 06510, USA.
Neural Regen Res. 2012 Sep 15;7(26):2075-9. doi: 10.3969/j.issn.1673-5374.2012.26.009.
Chronic pain often accompanies immune-related diseases with an elevated level of IgG immune complex (IgG-IC) in the serum and/or the affected tissues though the underlying mechanisms are largely unknown. Fc gamma receptors (FcγRs), known as the receptors for the Fc domain of immunoglobulin G (IgG), are typically expressed on immune cells. A general consensus is that the activation of FcγRs by IgG-IC in such immune cells induces the release of proinflammatory cytokines from the immune cells, which may contribute to the IgG-IC-mediated peripheral sensitization. In addition to the immune cells, recent studies have revealed that FcγRI, but not FcγRII and FcγRIII, is also expressed in a subpopulation of primary sensory neurons. Moreover, IgG-IC directly excites the primary sensory neurons through neuronal FcγRI. These findings indicate that neuronal FcγRI provides a novel direct linkage between immunoglobulin and primary sensory neurons, which may be a novel target for the treatment of pain in the immune-related disorders. In this review, we summarize the expression pattern, functions, and the associated cellular signaling of FcγRs in the primary sensory neurons.
慢性疼痛常伴随免疫相关疾病，血清和/或受影响组织中的IgG免疫复合物（IgG-IC）水平升高，但其潜在机制大多未知。Fcγ受体（FcγRs）是免疫球蛋白G（IgG）Fc结构域的受体，通常在免疫细胞上表达。普遍的共识是，免疫细胞中IgG-IC激活FcγRs会诱导免疫细胞释放促炎细胞因子，这可能导致IgG-IC介导的外周致敏。除免疫细胞外，最近的研究表明，FcγRI（而非FcγRII和FcγRIII）也在初级感觉神经元的一个亚群中表达。此外，IgG-IC通过神经元FcγRI直接兴奋初级感觉神经元。这些发现表明，神经元FcγRI在免疫球蛋白和初级感觉神经元之间提供了一种新的直接联系，这可能是治疗免疫相关疾病疼痛的新靶点。在这篇综述中，我们总结了FcγRs在初级感觉神经元中的表达模式、功能及相关细胞信号传导。
