Axonally derived matrilin-2 induces proinflammatory responses that exacerbate autoimmune neuroinflammation
Anna Jonas, … , Helmut Butzkueven, Melissa Gresle
Anna Jonas, … , Helmut Butzkueven, Melissa Gresle
Published October 20, 2014
Citation Information: J Clin Invest. 2014;124(11):5042-5056. https://doi.org/10.1172/JCI71385.
View: Text | PDF
Research Article Neuroscience

Axonally derived matrilin-2 induces proinflammatory responses that exacerbate autoimmune neuroinflammation

Abstract

In patients with multiple sclerosis (MS) and mice with experimental autoimmune encephalomyelitis (EAE), inflammatory axonal injury is a major determinant of disability; however, the drivers of this injury are incompletely understood. Here, we used the EAE model and determined that the extracellular matrix protein matrilin-2 (MATN2) is an endogenous neuronal molecule that is regulated in association with inflammatory axonal injury. Compared with WT mice, mice harboring a deletion of Matn2 exhibited reduced disease severity and axon damage following induction of EAE. Evaluation of neuron-macrophage cocultures revealed that exogenous MATN2 specifically signals through TLR4 and directly induces expression of proinflammatory genes in macrophages, promoting axonal damage. Moreover, the MATN2-induced proinflammatory response was attenuated greatly in macrophages from Myd88 KO mice. Examination of brain sections from patients with MS revealed that MATN2 is expressed in lesions but not in normal-appearing white matter. Together, our results indicate that MATN2 is a deleterious endogenous neuroaxonal injury response signal that activates innate immune cells and could contribute to early axonal damage in CNS inflammatory diseases like MS.

Authors

Anna Jonas, Stefan Thiem, Tanja Kuhlmann, Raimund Wagener, Attila Aszodi, Cameron Nowell, Karin Hagemeier, Louise Laverick, Victoria Perreau, Vilija Jokubaitis, Ben Emery, Trevor Kilpatrick, Helmut Butzkueven, Melissa Gresle

×

Figure 6

MATN2 contributes to neuroaxonal injury.

Options: View larger image (or click on image) Download as PowerPoint
MATN2 contributes to neuroaxonal injury. (A) Axon counts (mean ± SEM) in...
(A) Axon counts (mean ± SEM) in the dorsal spinal cord columns of healthy and EAE WT and Matn2 KO mice at day 21 and 45 are reduced in EAE WT mice but not in EAE KO mice (n = 4–6 per group). ***P < 0.001, **P < 0.01, P ≥ 0.5 = not significant, 2-way ANOVA. (B) pNfH levels (mean ± SEM; ELISA) as a marker of axonal injury in sera of WT and Matn2 KO mice at EAE day 21 (n = 21–26 per genotype). **P < 0.01, Student’s t test. (C) Neuron/macrophage cocultures stained with Calcein AM and Ethidium Homodimer after 24-hour incubation with recombinant MATN2 (1 μg/ml) or untreated controls. Arrows indicate neurite beading and transection in the presence of MATN2. Scale bar: 50 μm; 12.5 μm (inset). (D) Assessment of neurite length and number of branches (mean ± SEM; percentage) of 100 neurons in coculture after 24-hour incubation with recombinant MATN2 (1 μg/ml) (n = 3 cultures per condition, 3 independent experiments). ***P < 0.001; **P < 0.01, Student’s t test. (E) Expression of proinflammatory cytokines (mean ± SEM, qRT-PCR) in WT macrophage/KO neuron cocultures following a 24-hour incubation with recombinant MATN2 (1 μg/ml) (n = 2–4 cultures per condition, 3 independent experiments). Results are shown relative to untreated controls (dotted line). ****P < 0.0001; *P < 0.05, P ≥ 0.5 = not significant, Student’s t test.