Expression of α₂‐macroglobulin receptor/low density lipoprotein receptor‐related protein is increased in reactive and neoplastic glial cells

Abstract

a,-Macroglobuhn receptor/low density hpoprotem receptor-related protein (cc,M-RILRP) IS a multi-functional cell-surface receptor that has been tmphcated m diverse physiologic processes In normal human brain, a,M-R/LRP IS expressed prmclpally by pyramldal neurons with locahzation to cell bodies and proximal processes By contrast, a,M-R/LRP 1s not present m either the cell bodies or processes of most normal macrogha (mcludmg astrocytes) In this mvestlgatlon, we studied the expression of a,M-FULRP m the brain, followmg tissue InJury or neoplastic transformation, by lmmunohistochemlstry Significantly increased a,M-R/LRP lmmunoreactivlty was ldentlfied m reactive astrocytes, mdlcatmg that expression of this receptor is regulated m viva m response to brain injury a2M-R/LRP lmmunoreactivlty was also detected m ghal cell tumors. this finding 1s novel since malignant transformation 1s typically thought to turn off expression of this receptor

LDL receptor-related protein-1 is a sialic-acid-independent receptor for myelin-associated glycoprotein that functions in neurite outgrowth inhibition by MAG and CNS myelin

“…In CNS injury, LRP1 expression significantly increases in reactive astrocytes (Lopes et al, 1994). Our previous studies suggest that LRP1-dependent phagocytosis of myelin debris occurs across diverse cell types (Gaultier et al, 2009).…”

“…In the normal human brain, LRP1 is expressed by almost all neuronal populations (Wolf et al, 1992;Bu et al, 1994;Lopes et al, 1994). In CNS injury, LRP1 expression significantly increases in reactive astrocytes (Lopes et al, 1994).…”

Expression analysis of apolipoprotein E and its associated genes in gastric cancer

“…Studies have shown that increased LRP1 expression correlates with high levels of invasion (19) and, conversely, silencing of LRP1 prevents the spread of malignant cells (20). In gliomas, LRP1 expression in tumors greatly exceeded that in normal brain tissues (21) and its expression was found to be correlated with tumor aggressiveness (22). The abundant expression of LRP1 mRNA suggests that it may be involved in the uptake of ApoE phospholipid discoidal particles or ApoE-enriched high-density lipoprotein in gastric cancer.…”

The Low-Density Lipoprotein Receptor-Related Protein Is a Pro-Survival Receptor in Schwann Cells: Possible Implications in Peripheral Nerve Injury

“…Interferon-␥ shuts down LRP-1 expression in macrophages by regulating transcription (LaMarre et al, 1991;Hussaini et al, 1996). In the CNS, disorders associated with inflammation increase LRP-1 expression in astrocytes (Rebeck et al, 1993;Lopes et al, 1994). LRP-1 may facilitate astrocyte activation because the LRP-1 antagonist, RAP, inhibits astrocyte activation in culture (LaDu et al, 2001).…”