Datta-Mitra Ananya, Kundu-Raychaudhuri Smriti, Mitra Anupam, Raychaudhuri Siba P
Division of Rheumatology, Allergy and Clinical Immunology, University of California Davis, School of Medicine, Davis, CA, 95616, United States of America; VA Medical Center Sacramento, Mather, CA, 95655, United States of America.
VA Medical Center Sacramento, Mather, CA, 95655, United States of America; Department of Dermatology, University of California Davis, School of Medicine, Sacramento, CA, 95817, United States of America.
PLoS One. 2015 Apr 15;10(4):e0121626. doi: 10.1371/journal.pone.0121626. eCollection 2015.
Increasing evidence points to a role for the extra-neuronal nerve growth factor (NGF) in acquired immune responses. However, very little information is available about its role and underlying mechanism in innate immunity. The role of innate immunity in autoimmune diseases is becoming increasingly important. In this study, we explored the contribution of pleiotropic NGF in the innate immune response along with its underlying molecular mechanism with respect to IL-1β secretion.
Human monocytes, null and NLRP3 deficient THP-1 cell lines were used for this purpose. We determined the effect of NGF on secretion of IL-1β at the protein and mRNA levels. To determine the underlying molecular mechanism, the effect of NGF on NLRP1/NLRP3 inflammasomes and its downstream key protein, activated caspase-1, were evaluated by ELISA, immunoflorescence, flow cytometry, and real-time PCR.
In human monocytes and null THP-1 cell line, NGF significantly upregulates IL-1β at protein and mRNA levels in a caspase-1 dependent manner through its receptor, TrkA. Furthermore, we observed that NGF induces caspase-1 activation through NLRP1/NLRP3 inflammasomes, and it is dependent on the master transcription factor, NF-κB.
To best of our knowledge, this is the first report shedding light on the mechanistic aspect of a neuroregulatory molecule, NGF, in innate immune response, and thus enriches our understanding regarding its pathogenic role in inflammation. These observations add further evidence in favor of anti-NGF therapy in autoimmune diseases and also unlock a new area of research about the role of NGF in IL-1β mediated diseases.
越来越多的证据表明，神经元外神经生长因子（NGF）在获得性免疫反应中发挥作用。然而，关于其在固有免疫中的作用及潜在机制的信息却非常有限。固有免疫在自身免疫性疾病中的作用日益重要。在本研究中，我们探讨了多效性NGF在固有免疫反应中的作用及其与白细胞介素-1β（IL-1β）分泌相关的潜在分子机制。
为此使用了人单核细胞、野生型和NLRP3缺陷型THP-1细胞系。我们在蛋白质和mRNA水平上测定了NGF对IL-1β分泌的影响。为确定潜在的分子机制，通过酶联免疫吸附测定（ELISA）、免疫荧光、流式细胞术和实时聚合酶链反应（PCR）评估了NGF对NLRP1/NLRP3炎性小体及其下游关键蛋白活化半胱天冬酶-1的影响。
在人单核细胞和野生型THP-1细胞系中，NGF通过其受体TrkA以半胱天冬酶-1依赖性方式在蛋白质和mRNA水平上显著上调IL-1β。此外，我们观察到NGF通过NLRP1/NLRP3炎性小体诱导半胱天冬酶-1活化，且这依赖于主要转录因子核因子κB（NF-κB）。
据我们所知，这是第一份揭示神经调节分子NGF在固有免疫反应中机制方面的报告，从而丰富了我们对其在炎症中致病作用的理解。这些观察结果进一步支持了在自身免疫性疾病中进行抗NGF治疗的证据，也开启了关于NGF在IL-1β介导疾病中作用的新研究领域。
