Specific oligodendrocyte populations have differential spatial distribution and susceptibility to injury

Abstract

Oligodendrocytes (OLs), the myelinating cells of the central nervous system, are transcriptionally heterogeneous,1 the origin and functional consequences of which are unknown. Functional heterogeneity of MOLs might correlate with the local environment or their interactions with different neuron types.2 Here, we show that distinct MOL populations have spatial preference in the mammalian central nervous system and differential susceptibility to traumatic spinal cord injury. We also show that the generation of distinct MOL populations is independent of the OPC developmental origin. We found that OPCs originating from the previously described developmental waves3-5 have comparable potential to differentiate into the main MOL populations. Furthermore, we found that MOL type 2 (MOL2) is enriched in the spinal cord and almost absent in the brain, while MOL5/6 is enriched with age in all analyzed regions. MOL2 and MOL5/6 also have differential preference for motor and sensory tracts in the spinal cord. In the context of disease, we found that MOL2 and MOL5/6 have differential susceptibility to traumatic spinal cord injury, where MOL2 are lost and MOL5/6 increased their contribution to the OL lineage. Importantly, MOL2 susceptibility is disease specific, as we found MOL2 is not lost in a mouse model of multiple sclerosis. Our results demonstrate that the MOL populations, previously described by single-cell transcriptomics,1 have distinct spatial preference and responses. We anticipate our study to pave the way for a better understanding of the MOL populations-specific functional roles in development, health, and disease, allowing for better targeting of the OL subtypes important for the regeneration and repair of the central nervous system.