MATRIX - "Modeling Macrophages Activation Pattern in X-linked Adrenoleukodystrophy, Metachromatic Leukodystrophy and Adult Onset Leukoencephalopathy With Axonal Spheroids and Pigmented Glia"

X-linked Adrenoleukodystrophy (X-ALD), Metachromatic Leukodystrophy (MLD) and Adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) are among the most frequent inherited leukodystrophies. X-ALD and MLD can affect both children and adults, while it is thought that ALSP onset exclusively during adulthood. These three diseases are characterized by phenotypic variability and poor genotype-phenotype correlation. In childhood forms of MLD and childhood cerebral ALD (C-CALD) a devastating cerebral demyelination and neuronal degeneration lead to a rapid neurologic degradation and premature death. Patients with the adult form of X-ALD (adrenomyeloneuropathy (AMN), 60% of males) display a progressive spastic paraplegia without brain involvement. However, 20% of AMN patients will also develop cerebral ALD. Patients diagnosed with the juvenile/adult (JA-) MLD form are affected by a progressive decline of their cognitive function, followed later by that of the motor abilities. ALSP patients present a rapidly progressive neurodegenerative disorder that impairs behavioural, cognitive and motor functions.

Several arguments support the contribution of the immune response and neuroinflammation in these three leukodystrophies. In X-ALD, activation of microglia (macrophages of the CNS) plays an essential role in the acute demyelination phase, where a severe inflammatory process occurs. In ALSP, the dysfunctional protein (CSF1R) is almost exclusively expressed in microglia. Even if MLD is not considered as a neuroinflammatory disease per se, microglia activation and increased inflammatory cytokines are observed in the brain of MLD patients and mice. Even if the most commonly accepted hypothesis is that neuroinflammation is caused by secondary activation of microglia following phagocytosis of myelin debris full of undegraded material, a primitive role of the inflammation due to macrophages (MAC) dysfunction has emerged in recent years.

MATRIX proposes to explore how disease-related mutations affect key components of MAC activation responses and how it reflects on their functionality.