Targeting chemoattractant chemokine (C–C motif) ligand 2 derived from astrocytes is a promising therapeutic approach in the treatment of neuromyelitis optica spectrum disorders

Abstract

IntroductionAquaporin-4 immunoglobulin G (AQP4-IgG)-induced astrocytes injury is a key mechanism in the pathogenesis of neuromyelitis spectrum disorder (NMOSD), and although CCL2 is involved, its specific role has not been reported. We aimed to further investigate the role and potential mechanisms of CCL2 in AQP4-IgG-induced astrocyte injury.MethodsFirst, we evaluated CCL2 levels in paired samples of subject patients by automated microfluidic platform, Ella®. Second, we knock down astrocyte's CCL2 gene in vitro and in vivo to define the function of CCL2 in AQP4-IgG-induced astrocyte injury. Third, astrocyte injury and brain injury in live mice were assessed by immunofluorescence staining and 7.0T MRI, respectively. Western blotting and high-content screening were conducted to clarify the activation of inflammatory signaling pathways, and changes in CCL2 mRNA and cytokine/chemokines were measured by qPCR technique and flow cytometry, respectively.ResultsThere were greatly higher CSF-CCL2 levels in NMOSD patients than that in other non-inflammatory neurological diseases (OND) groups. Blocking astrocyte CCL2 gene expression can efficiently mitigate AQP4-IgG-induced damage in vitro and in vivo. Interestingly, prevention of CCL2 expression could decrease other inflammatory cytokines released, including IL-6 and IL-1β. Our data suggest that CCL2 involves in the initiation and plays a pivotal role in AQP4-IgG-damaged astrocytes.DiscussionOur results indicate that CCL2 may serve as a promising candidate target for inflammatory disorder therapy, including NMOSD.

The landscape of PBMCs in AQP4‐IgG seropositive NMOSD and MOGAD, assessed by high dimensional mass cytometry

“…Previous studies reported that exposure of NMOSD‐targeted cell astrocytes to NMO‐IgG would induce chemoattractant chemokine ligand 2 (CCL2) expression to increase or release 14,17 . As we know, CCL2 binds to its receptor, CCR2, which is primarily produced in activated MNPs and NK cells 18,19 .…”

“…We discovered a considerable decrease of CCR2+ nonclassical monocytes in both patients (Figure 3G), with an average of about 7.35% and 7.86% for NMOSD and MOGAD, respectively, that can potentially be involved in the pathogenesis of disease. Previous studies proved that NMO‐IgG stimulated an immunological response, including CCL2 release in rat astrocyte cultures 14,28 . Considering that CCL2 is a strong chemotactic stimulant of CCR2+ myeloid cells and is essential for the creation of inflammatory infiltration in the brain, there were much lower CCR2+ cells in the periphery of NMOSD patients.…”

“…The TRIzol™ reagent extracted total RNA from PBMCs as previously described 13,14 . A NanoDrop® ND‐1000 spectrophotometer was utilized to ascertain the concentration and purity of RNA.…”

“…The TRIzol™ reagent extracted total RNA from PBMCs as previously described. 13,14 A NanoDrop® ND-1000 spectrophotometer was utilized to ascertain the concentration and purity of RNA. Making use of random hexamer primers, the Transcriptor First Strand cDNA Synthesis Kit, and anchored oligo (dT), RNA was utilized to create cDNA.…”

The function of astrocytes and their role in neurological diseases

“…A recent study suggested that gene therapy may be a promising approach in NMO. The in vivo and in vitro experiments discovered that blocking CCL2 gene expression in astrocytes alleviates AQP4-IgG-induced damage and reduces the release of other inflammatory cytokines, such as IL-6 and IL-1β (Wang et al, 2023).…”