Distribution of testican expression in human brain

Abstract

Testican is a putative extracellular heparan/ chondroitin sulfate proteoglycan of unknown function that is expressed in a variety of human tissues at widely different levels but is most abundant in the brain. In mice, testican mRNA has been detected only in brain and it is therefore likely to have an important function in the central nervous system. RNA blot analysis reveals the relative intensity of testican in various regions of the human brain. Levels of testican message are most pronounced in the thalamus, hippocampus, occipital lobe, nucleus accumbens, temporal lobe, and caudate nucleus, with somewhat lower levels in the cerebral cortex, medulla oblongata, frontal lobe, amygdala, putamen, spinal cord, substantia nigra, and cerebellum. In situ hybridization reveals the cellular distribution of the mRNA within these areas to be highest in neurons and in choroid plexus epithelium, and moderately lower in ependymal cells lining the ventricles and in vascular endothelial cells. Testican mRNA is not detected in oligodendrocytes or in most astrocytes. However, astrocytes in regions of reactive gliosis do express testican mRNA. These findings, along with a cysteine-rich pattern similarity to neurocan, brevican, versican, and other proteoglycans found in brain, suggest that testican may be a part of the specialized extracellular matrix of the brain.

Altered expression pattern of testican-1 mRNA after brain injury

“…1A, inset, arrows) and choroid plexus (Fig. 1A, white arrows), which is consistent with the previous report (13). On the other hand, testican-1 mRNA increased mainly in the margin surrounding the necrotic region of the cortex at day 7 after cryo-injury (Fig.…”

“…3), suggesting that both molecules are expressed in reactive astrocytes. Previous study has shown that in Northern blot analysis of various mouse tissues testican-1 mRNA expression is restricted to the brain (13). In situ hybridization histochemistry reveals that testican-1 mRNA is expressed in pyramidal neurons of the hippocampus.…”

“…Testican-1 and testican-3 are predominately expressed in neurons of the adult and developing mouse brain (3,4,8). Furthermore, testican-1 mRNA is also expressed abundantly in hippocampal neurons as well as ependymal cells in human brain (13). However, it is not detected in oligodendrocytes or astrocytes under normal conditions, but is induced in regions of reactive gliosis after infarction (13), suggesting that testican-1 is involved in injury response.…”

“…Furthermore, testican-1 mRNA is also expressed abundantly in hippocampal neurons as well as ependymal cells in human brain (13). However, it is not detected in oligodendrocytes or astrocytes under normal conditions, but is induced in regions of reactive gliosis after infarction (13), suggesting that testican-1 is involved in injury response. However, the expression of testican-1 in response to brain injury has not been studied in detail.…”

Mathematical modeling of noise and discovery of genetic expression classes in gliomas

“…Members of this family are upregulated during seizures and long-term potentiation (Kato et al, 1997). Clone 280244 (Class 1b) is 54% similar to testican, a putative extracellular heparan/ chondroitin sulfate proteoglycan expressed in a variety of human tissues but is most abundant in brain (Marr et al, 2000). Using subtractive hybridization, Genini et al (1996) identified testican as highly down-regulated in an embryonal-rhabdomyosarcoma cell line as compared to human primary myobasts.…”