Meninges: A Widespread Niche of Neural Progenitors for the Brain

Abstract

Emerging evidence highlights the several roles that meninges play in relevant brain functions as they are a protective membrane for the brain, produce and release several trophic factors important for neural cell migration and survival, control cerebrospinal fluid dynamics, and embrace numerous immune interactions affecting neural parenchymal functions. Furthermore, different groups have identified subsets of neural progenitors residing in the meninges during development and in the adulthood in different mammalian species, including humans. Interestingly, these immature neural cells are able to migrate from the meninges to the neural parenchyma and differentiate into functional cortical neurons or oligodendrocytes. Immature neural cells residing in the meninges promptly react to brain disease. Injury-induced expansion and migration of meningeal neural progenitors have been observed following experimental demyelination, traumatic spinal cord and brain injury, amygdala lesion, stroke, and progressive ataxia. In this review, we summarize data on the function of meninges as stem cell niche and on the presence of immature neural cells in the meninges, and discuss their roles in brain health and disease. Furthermore, we consider the potential exploitation of meningeal neural progenitors for the regenerative medicine to treat neurological disorders.

Environmental Enrichment and Fluoxetine Neurogenic Stimuli Increase ß3-Tubulin Immature Neurons in Meninges Through Trkb-Mediated Signaling

“…1H-K). NPs in meninges are characterized by features of radial glia-like cells expressing GLAST and of immature neurons expressing β3-Tubulin [13]. We found that both GLAST + neural precursors and β3-Tubulin + cells increased in the treated group compared to the control (Fig.…”

“…[11]. Recently, a subset of meningeal-residing neural progenitors has been identified both during development and adulthood in different mammals, including humans [11][12][13][14][15][16]. Single-cell RNA sequencing (scRNAseq) analysis of meningeal cells identified a small fraction of cells with a signature corresponding to radial glia-like cells, expressing GLAST and a population with a neuroblast signature expressing β3-Tubulin [17].…”

“…Meningeal stem cell niche is composed by specific trophic extracellular matrix components called fractones and it is able to sense and respond to neurotrophic stimuli including FGF2, NGF, and EGF [19][20][21]. Noteworthly, NPs in meninges have been shown to react to CNS diseases, including spinal cord and brain injuries, amygdala lesion, stroke and progressive ataxia [13,22]. Meninges may therefore represent a functional niche for neural progenitors, however, the response of NPs in meninges to neurogenic stimuli such as drugs (i.e., fluoxetine) [23] or EE tasks [24] has never been assessed.…”

Brain Barriers and brain fluids research in 2020 and the fluids and barriers of the CNS thematic series on advances in in vitro modeling of the blood–brain barrier and neurovascular unit

“…The importance of the arachnoid membrane in regulating CSF composition is understudied. Emerging evidence indicates the importance of the meninges as a niche for neural progenitor cells [60]. These cells may be a therapeutic target for treating neurological disorders.…”

Editorial: Metabolic Regulation of Stem Cells and Tissue Growth

“…Karakatsani et al highlighted the many interactions between blood vessels and stem cells in the brain. Similarly to adult stem cells from different tissues (e.g., pancreas, liver, and adipose tissue), neural stem cells reside in close proximity to specialized blood vessels, which are highly organized with unique architecture characterized by dense network of planar, interconnected, and relatively non-tortuous (straight) vessels (Bifari et al, 2017b;Knobloch and Jessberger, 2017;Decimo et al, 2020). Importantly, specialized blood vessels at the NSC niche have partially permeable blood brain barrier (BBB) allowing the access of signals deriving from the blood.…”