Neurocan in the embryonic avian heart and vasculature

Abstract

The chondroitin sulfate proteoglycan (CSPG) neurocan was previously considered to be nervous-system specific. However, we have found neurocan in the embryonic heart and vasculature. In stage 11 quail embryos, neurocan was prominently expressed in the myocardium, dorsal mesocardium, heart-forming fields, splanchnic mesoderm, and vicinity of the extraembryonic vaculature, and at lower levels in the endocardium. A comparison of neurocan staining with QH1 staining of vascular endothelial cells demonstrates that neurocan is frequently expressed by cells adjacent to endothelial cells, rather than by endothelial cells themselves. In some cases, a dispersed subset of cells are neurocan-positive in a field of cells that otherwise appear uniform in morphology. Later in development, neurocan expression becomes relatively limited to the nervous system. However, even in 10-day embryos, neurocan is expressed in the chorio-allantoic membrane in the tissue that separates closely packed, small-diameter blood vessels. In summary, our results suggest that neurocan may function as a barrier that regulates vascular patterning during development. Anat Rec Part A 272A: 556 -562, 2003.

Extracellular matrix components associated with remodeling processes in brain

“…Neurocan and tenascin-C have also been observed outside the central nervous system. While tenascin-C has been found to be associated with a large variety of remodeling events in different tissues [4], neurocan expression outside the nervous system appears to be rather restricted, to activated T lymphocytes, lymph nodes and the developing avian heart [23,39,40]. However, activated T lymphocytes can enter almost any part of the body.…”

Neurocan developmental expression and function during early avian embryogenesis

“…This observation of non-neural tissue localization of neurocan in meninges, skin, and mesenchyme could point to neural crest cells, transient cell populations which form the meninges, the melanocytes which give rise to the pigment of the skin and hair, and supply mesenchyme to several other developing organs. Neurocan has also been reported to be expressed in the heart and vasculature of avian embryos [7,8], and in mouse T lymphocytes [9] and neoplastic mammary glands [10].…”

“…For β-actin, a fragment of 187-bp was amplified with the following primers: sense 5'-CGG TAT TGT CAC CAA CTG G-3' and antisense 5'-TGG CTA CAT ACA TGG CTG G-3' were used in a parallel reaction as the neurocan primers. The quail neurocan [8] and chick β-actin [29,30] primers were the same as those published previously. Single stranded cDNA was synthesized employing as template 2μg of total RNA from embryos according to the manufacturer OneStep RT-PCR Kit protocol (Qiagen); the RNA was omitted from the reaction in the negative control samples.…”

“…The neurocan function is elusive [4][5][6][7][8]25]. In vitro studies have shown that neurocan is able to modulate cell-binding, axon guidance and synapse formation during the development of the nervous system via adhesion molecules [3,11,13,27].…”