CXCL13/CXCR5 signalling is pivotal to preserve motor neurons in amyotrophic lateral sclerosis.

Background: CXCL13 is a B and T lymphocyte chemokine that mediates neuroinflammation through its receptor CXCR5. This chemokine is highly expressed by motoneurons (MNs) in Amyotrophic Lateral Sclerosis (ALS) SOD1G93A (mSOD1) mice during the disease, particularly in fast-progressing mice. Accordingly, in this study, we investigated the role of this chemokine in ALS.
Methods: We used in vitro and in vivo experimental paradigms derived from ALS mice and patients to investigate the expression level and distribution of CXCL13/CXCR5 axis and its role in MN death and disease progression. Moreover, we compared the levels of CXCL13 in the CSF and serum of ALS patients and controls.
Findings: CXCL13 and CXCR5 are overexpressed in the spinal MNs and peripheral axons in mSOD1 mice. CXCL13 inhibition in the CNS of ALS mice resulted in the exacerbation of motor impairment (n = 4/group;Mean_Diff.=27.81) and decrease survival (n = 14_Treated:19.2 ± 1.05wks, n = 17_Controls:20.2 ± 0.6wks; 95% CI: 0.4687-1.929). This was corroborated by evidence from primary spinal cultures where the inhibition or activation of CXCL13 exacerbated or prevented the MN loss. Besides, we found that CXCL13/CXCR5 axis is overexpressed in the spinal cord MNs of ALS patients, and CXCL13 levels in the CSF discriminate ALS (n = 30) from Multiple Sclerosis (n = 16) patients with a sensitivity of 97.56%.
Interpretation: We hypothesise that MNs activate CXCL13 signalling to attenuate CNS inflammation and prevent the neuromuscular denervation. The low levels of CXCL13 in the CSF of ALS patients might reflect the MN dysfunction, suggesting this chemokine as a potential clinical adjunct to discriminate ALS from other neurological diseases.
Funding: Vaccinex, Inc.; Regione Lombardia (TRANS-ALS).
Competing Interests: Declaration of Competing Interest Dr. Bendotti reports grants from Vaccinex Inc.; Dr. Nardo has nothing to disclose. Dr. Trolese has nothing to disclose. Dr Mariani has nothing to disclose. Dr. Terao has nothing to disclose. Dr. de Paola has nothing to disclose. Dr. Fabbrizio has nothing to disclose. Dr. Sironi has nothing to disclose. Dr. Kurosaki has nothing to disclose. Dr. Bonanno has nothing to disclose. Dr. Marcuzzo has nothing to disclose. Dr. Bernasconi has nothing to disclose. Dr. Trojsi has nothing to disclose. Dr. Aronica has nothing to disclose.
(Copyright © 2020 The Authors. Published by Elsevier B.V. All rights reserved.)