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Identification of a molecular target of psychosine and its role in globoid cell formation.

Im DS, Heise CE, Nguyen T, O'Dowd BF, Lynch KR - J. Cell Biol. (2001)

Bottom Line: The glycosphingolipid, psychosine (d-galactosyl-beta-1,1' sphingosine), accumulates to micromolar levels in GLD patients who lack the degradative enzyme galactosyl ceramidase.Here we document that an orphan G protein-coupled receptor, T cell death-associated gene 8, is a specific psychosine receptor.Treatment of cultured cells expressing this receptor with psychosine or structurally related glycosphingolipids results in the formation of globoid, multinuclear cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA.

ABSTRACT
Globoid cell leukodystrophy (GLD) is characterized histopathologically by apoptosis of oligodendrocytes, progressive demyelination, and the existence of large, multinuclear (globoid) cells derived from perivascular microglia. The glycosphingolipid, psychosine (d-galactosyl-beta-1,1' sphingosine), accumulates to micromolar levels in GLD patients who lack the degradative enzyme galactosyl ceramidase. Here we document that an orphan G protein-coupled receptor, T cell death-associated gene 8, is a specific psychosine receptor. Treatment of cultured cells expressing this receptor with psychosine or structurally related glycosphingolipids results in the formation of globoid, multinuclear cells. Our discovery of a molecular target for psychosine suggests a mechanism for the globoid cell histology characteristic of GLD, provides a tool with which to explore the disjunction of mitosis and cytokinesis in cell cultures, and provides a platform for developing a medicinal chemistry for psychosine.

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Autoradiogram of a human multiple tissue array RNA dot blot (CLONTECH Laboratories, Inc.) hydbridized with 32P-labeled human TDAG8 DNA.
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Figure 4: Autoradiogram of a human multiple tissue array RNA dot blot (CLONTECH Laboratories, Inc.) hydbridized with 32P-labeled human TDAG8 DNA.

Mentions: Recently, the generation of large, multinuclear (globoid) cells characteristic of Krabbe's disease was reproduced in vitro by treating human U937 monocyte cells with PSY (Kanazawa et al. 2000). We replicated this finding (not shown) and further used reverse trascriptase PCR to discover that TDAG8 is expressed in these cells, but not in other cell lines (e.g., HEK293 and K562) that do not form globoid cells in response to PSY treatment (Im, D.S., and K.R. Lynch, unpublished data). To discover the human tissues that express TDAG8, we probed a human multiple tissue RNA array with radiolabeled TDAG8 DNA. As documented in Fig. 4, TDAG8 RNA is found most prominently in extracts of spleen (fetal and adult), lymph node, and peripheral blood leukocytes, although a low level signal was found in virtually all human tissue extracts. This expression pattern, coupled with our observation that THP1 and HL60 cell cultures express TDAG8 (not shown), is consistent with TDAG8 gene expression in monocytes and macrophages, including tissue macrophages such as microglia.


Identification of a molecular target of psychosine and its role in globoid cell formation.

Im DS, Heise CE, Nguyen T, O'Dowd BF, Lynch KR - J. Cell Biol. (2001)

Autoradiogram of a human multiple tissue array RNA dot blot (CLONTECH Laboratories, Inc.) hydbridized with 32P-labeled human TDAG8 DNA.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2169470&req=5

Figure 4: Autoradiogram of a human multiple tissue array RNA dot blot (CLONTECH Laboratories, Inc.) hydbridized with 32P-labeled human TDAG8 DNA.
Mentions: Recently, the generation of large, multinuclear (globoid) cells characteristic of Krabbe's disease was reproduced in vitro by treating human U937 monocyte cells with PSY (Kanazawa et al. 2000). We replicated this finding (not shown) and further used reverse trascriptase PCR to discover that TDAG8 is expressed in these cells, but not in other cell lines (e.g., HEK293 and K562) that do not form globoid cells in response to PSY treatment (Im, D.S., and K.R. Lynch, unpublished data). To discover the human tissues that express TDAG8, we probed a human multiple tissue RNA array with radiolabeled TDAG8 DNA. As documented in Fig. 4, TDAG8 RNA is found most prominently in extracts of spleen (fetal and adult), lymph node, and peripheral blood leukocytes, although a low level signal was found in virtually all human tissue extracts. This expression pattern, coupled with our observation that THP1 and HL60 cell cultures express TDAG8 (not shown), is consistent with TDAG8 gene expression in monocytes and macrophages, including tissue macrophages such as microglia.

Bottom Line: The glycosphingolipid, psychosine (d-galactosyl-beta-1,1' sphingosine), accumulates to micromolar levels in GLD patients who lack the degradative enzyme galactosyl ceramidase.Here we document that an orphan G protein-coupled receptor, T cell death-associated gene 8, is a specific psychosine receptor.Treatment of cultured cells expressing this receptor with psychosine or structurally related glycosphingolipids results in the formation of globoid, multinuclear cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA.

ABSTRACT
Globoid cell leukodystrophy (GLD) is characterized histopathologically by apoptosis of oligodendrocytes, progressive demyelination, and the existence of large, multinuclear (globoid) cells derived from perivascular microglia. The glycosphingolipid, psychosine (d-galactosyl-beta-1,1' sphingosine), accumulates to micromolar levels in GLD patients who lack the degradative enzyme galactosyl ceramidase. Here we document that an orphan G protein-coupled receptor, T cell death-associated gene 8, is a specific psychosine receptor. Treatment of cultured cells expressing this receptor with psychosine or structurally related glycosphingolipids results in the formation of globoid, multinuclear cells. Our discovery of a molecular target for psychosine suggests a mechanism for the globoid cell histology characteristic of GLD, provides a tool with which to explore the disjunction of mitosis and cytokinesis in cell cultures, and provides a platform for developing a medicinal chemistry for psychosine.

Show MeSH
Related in: MedlinePlus