Cerebrospinal fluid regulates skull bone marrow niches via direct access through dural channels

Mazzitelli, Smyth and colleagues show that cerebrospinal fluid gains direct access to skull bone marrow niches via dura-skull channels, allowing for the CNS context-dependent regulation of immune supply to the meninges. It remains unclear how immune cells from skull bone marrow niches are recruited to the meninges. Here we report that cerebrospinal fluid (CSF) accesses skull bone marrow via dura-skull channels, and CSF proteins signal onto diverse cell types within the niches. After spinal cord injury, CSF-borne cues promote myelopoiesis and egress of myeloid cells into meninges. This reveals a mechanism of CNS-to-bone-marrow communication via CSF that regulates CNS immune responses.

Automated summary

The study reveals that cerebrospinal fluid gains direct access to skull bone marrow niches via dura-skull channels and the proteins in the cerebrospinal fluid can signal onto diverse cell types within these niches. After spinal cord injury, the cues from cerebrospinal fluid promote myelopoiesis and the release of myeloid cells into the meninges.