Developmental biology of the meninges

Abstract

Summary The meninges are membranous layers surrounding the central nervous system. In the head, the meninges lie between the brain and the skull, and interact closely with both during development. The cranial meninges originate from a mesenchymal sheath on the surface of the developing brain, called primary meninx, and undergo differentiation into three layers with distinct histological characteristics: the dura mater, the arachnoid mater, and the pia mater. While genetic regulation of meningeal development is still poorly understood, mouse mutants and other models with meningeal defects have demonstrated the importance of the meninges to normal development of the calvaria and the brain. For the calvaria, the interactions with the meninges are necessary for the progression of calvarial osteogenesis during early development. In later stages, the meninges control the patterning of the skull and the fate of the sutures. For the brain, the meninges regulate diverse processes including cell survival, cell migration, generation of neurons from progenitors, and vascularization. Also, the meninges serve as a stem cell niche for the brain in the postnatal life. Given these important roles of the meninges, further investigation into the molecular mechanisms underlying meningeal development can provide novel insights into the coordinated development of the head.

A cellular atlas of the developing meninges reveals meningeal fibroblast diversity and function

“…Ogn 404 has enriched expression in arachnoid and dura that are adjacent to the calvarial mesenchyme that is 405 actively undergoing inter-membranous ossification at E14.5. The meninges, in particular the dura, have 406 previously been shown to play a role in regulating calvarial development (Dasgupta and Jeong, 2019;407 Greenwald, et al, 2000;Rice, et al, 2000;Mehrara, et al, 1999); however, the meningeal fibroblast 408 subtypes and the signals involved are incompletely understood. Our profiling of the meningeal fibroblasts 409 during a critical period of calvarial development could be quite valuable for understanding meninges-410 calvarial signaling.…”

“…The meninges, largely 45 composed of meningeal fibroblasts, also contains resident immune cells along with blood and lymphatic 46 vessels. Meningeal fibroblasts have emerged as critical players in CNS development (reviewed in (Dasgupta and Jeong, 2019;Siegenthaler and Pleasure, 2011). They are the major source of basement 48 membrane (BM) proteins that form the glial limitans (Hecht, et al, 2010a;Halfter, et al, 2002;Hartmann, 49 et al, 1992), and meninges-derived Cxcl12 is required for migration of Cajal-Retzius cells (Borrell and 50 Marin, 2006), proliferation of cerebellar radial glial progenitor cells (Haldipur, et al, 2015;Haldipur, et 51 al., 2014) and proper positioning of granule cell progenitors in the hippocampus and cerebellum (Reiss, 52 et al, 2002;Zhu, et al, 2002).…”

Innate and Adaptive Immunity Linked to Recognition of Antigens Shared by Neural Crest-Derived Tumors

“…Meningioma is defined as a group of mostly benign, slow-growing neoplasms that most likely derive from the meningothelial cells of the arachnoid layer. Meningiomas are classified into three major groups according to their WHO grade and biological behaviour [84,96].…”

Where Did the Dura Mater Come from?

“…Embryonic development of the meninges has been studied for more than a hundred years. 3 The primary meninx (also known as primitive meninx or meninx primitiva) give rise to the meninges, the calvaria, and the dermis of the scalp. Differentiation of the meninges progresses from a basal to apical direction.…”

“…Histological observations in human fetuses also suggest that the cranial meninges originated from both the neural crest and the mesoderm. 3,6 The most striking diversity of the neural crest derivatives is found in its cephalic domain where the neural crest replaces the role of mesoderm. 7 The neural crest is a vertebrate-specific migratory stem cell that generates diverse cell types and structures.…”