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Role of Ceramide from Glycosphingolipids and Its Metabolites in Immunological and Inflammatory Responses in Humans.

Iwabuchi K, Nakayama H, Oizumi A, Suga Y, Ogawa H, Takamori K - Mediators Inflamm. (2015)

Bottom Line: These observations suggest that the very long fatty acid chains of ceramide are critical for GSL-mediated outside-in signaling.Sphingosine is another component of ceramide, with the hydrolysis of ceramide by ceramidase producing sphingosine and fatty acids.Sphingosine is phosphorylated by sphingosine kinase to sphingosine-1-phosphate, which is involved in a wide range of cellular functions, including growth, differentiation, survival, chemotaxis, angiogenesis, and embryogenesis, in various types of cells.

View Article: PubMed Central - PubMed

Affiliation: Institute for Environmental and Gender-Specific Medicine, Juntendo University Graduate School of Medicine, 2-1-1 Tomioka Urayasu, Chiba 2790021, Japan ; Infection Control Nursing, Juntendo University Graduate School of Health Care and Nursing, Chiba 2790023, Japan ; Laboratory of Biochemistry, Juntendo University School of Health Care and Nursing, Chiba 2790023, Japan.

ABSTRACT
Glycosphingolipids (GSLs) are composed of hydrophobic ceramide and hydrophilic sugar chains. GSLs cluster to form membrane microdomains (lipid rafts) on plasma membranes, along with several kinds of transducer molecules, including Src family kinases and small G proteins. However, GSL-mediated biological functions remain unclear. Lactosylceramide (LacCer, CDw17) is highly expressed on the plasma membranes of human phagocytes and mediates several immunological and inflammatory reactions, including phagocytosis, chemotaxis, and superoxide generation. LacCer forms membrane microdomains with the Src family tyrosine kinase Lyn and the Gαi subunit of heterotrimeric G proteins. The very long fatty acids C24:0 and C24:1 are the main ceramide components of LacCer in neutrophil plasma membranes and are directly connected with the fatty acids of Lyn and Gαi. These observations suggest that the very long fatty acid chains of ceramide are critical for GSL-mediated outside-in signaling. Sphingosine is another component of ceramide, with the hydrolysis of ceramide by ceramidase producing sphingosine and fatty acids. Sphingosine is phosphorylated by sphingosine kinase to sphingosine-1-phosphate, which is involved in a wide range of cellular functions, including growth, differentiation, survival, chemotaxis, angiogenesis, and embryogenesis, in various types of cells. This review describes the role of ceramide moiety of GSLs and its metabolites in immunological and inflammatory reactions in human.

No MeSH data available.


Related in: MedlinePlus

LacCer-enriched microdomains. (a) Size of LacCer microdomains containing C16:0 and C24:0 fatty acid chain. (b) LacCer forms lipid microdomains on plasma membrane of human neutrophils and acts as a signal transduction platform. The C24 fatty acid chains of LacCer interdigitate into inner leaflet of plasma membranes and directly interact with Lyn and Gαi. These molecules associate with LacCer to mediate signaling from outside to inside, resulting in neutrophil chemotaxis, migration, and phagocytosis.
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fig2: LacCer-enriched microdomains. (a) Size of LacCer microdomains containing C16:0 and C24:0 fatty acid chain. (b) LacCer forms lipid microdomains on plasma membrane of human neutrophils and acts as a signal transduction platform. The C24 fatty acid chains of LacCer interdigitate into inner leaflet of plasma membranes and directly interact with Lyn and Gαi. These molecules associate with LacCer to mediate signaling from outside to inside, resulting in neutrophil chemotaxis, migration, and phagocytosis.

Mentions: Although GSL-enriched microdomains have been implicated in a number of important membrane events [2, 38, 39], the molecular mechanisms responsible for GSL-mediated cell functions are still unclear. One of the main issues centers around the association of GSLs with signal transducer molecules localized on the cytosolic side. However, we recently analyzed LacCer-enriched microdomains in human neutrophilic lineage cells [38]. LacCer, along with the Src family kinase Lyn, forms lipid microdomains on the plasma membranes of human neutrophils and is involved in several cellular functions, including chemotaxis, phagocytosis, and superoxide generation, highly dependent on Lyn [16, 29, 38]. HL-60 cells differentiated into neutrophilic lineage cells by DMSO (D-HL-60) were found to acquire superoxide generating activity, but not through LacCer, despite their expression of LacCer on plasma membranes [38]. Most LacCer and Lyn were recovered in the microdomain fractions of neutrophils and D-HL-60 cells. Lipidomics analysis revealed that LacCer in the neutrophil plasma membrane was mainly composed of molecular species containing C16:0, C24:1, and C24:0 fatty acid chains, whereas over 70% of LacCer in the plasma membranes of D-HL-60 cells contained C16:0 fatty acid chains, but only about 14% were C24:1 and C24:0 [11]. Lyn was immunoprecipitated by anti-LacCer antibody in neutrophils but not D-HL-60 cells. Importantly, Lyn was coimmunoprecipitated by anti-LacCer antibody from the detergent resistant membrane (DRM) fraction of plasma membranes from C24:0 and C24:1, but not C16:0 or C22:0, LacCer-loaded D-HL-60 cells. Anti-LacCer antibody induced superoxide generation from D-HL-60 cells loaded with C24:0-LacCer, but not C16:0-LacCer. Lyn colocalized with LacCer-enriched domains of D-HL-60 cells loaded with C24:0-LacCer, but not C16:0-LacCer. These results suggested that the C24 fatty acid chain of LacCer is indispensable for connecting Lyn with LacCer-enriched microdomains. Knockdown of Lyn molecules by human Lyn-specific short interfering RNA (siRNA) in D-HL-60 cells completely abolished the effects of C24:1-LacCer loading function [11], suggesting that Lyn is crucial for C24-LacCer-mediated neutrophil function. Experiments using azide-photoactivatable tritium-labeled C24- and C16-LacCer revealed that C24- but not C16-LacCer directly associated with Lyn and a heterotrimeric G protein subunit Gαi. These results confirm a specific direct interaction between C24-LacCer and the signal transduction molecules Lyn and Gαi, which are associated with the cytoplasmic layer via palmitic acid chains (Figure 2). LacCer species with very long fatty acids are indispensable for Lyn-coupled LacCer-enriched membrane microdomain-mediated neutrophil functions.


Role of Ceramide from Glycosphingolipids and Its Metabolites in Immunological and Inflammatory Responses in Humans.

Iwabuchi K, Nakayama H, Oizumi A, Suga Y, Ogawa H, Takamori K - Mediators Inflamm. (2015)

LacCer-enriched microdomains. (a) Size of LacCer microdomains containing C16:0 and C24:0 fatty acid chain. (b) LacCer forms lipid microdomains on plasma membrane of human neutrophils and acts as a signal transduction platform. The C24 fatty acid chains of LacCer interdigitate into inner leaflet of plasma membranes and directly interact with Lyn and Gαi. These molecules associate with LacCer to mediate signaling from outside to inside, resulting in neutrophil chemotaxis, migration, and phagocytosis.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4644562&req=5

fig2: LacCer-enriched microdomains. (a) Size of LacCer microdomains containing C16:0 and C24:0 fatty acid chain. (b) LacCer forms lipid microdomains on plasma membrane of human neutrophils and acts as a signal transduction platform. The C24 fatty acid chains of LacCer interdigitate into inner leaflet of plasma membranes and directly interact with Lyn and Gαi. These molecules associate with LacCer to mediate signaling from outside to inside, resulting in neutrophil chemotaxis, migration, and phagocytosis.
Mentions: Although GSL-enriched microdomains have been implicated in a number of important membrane events [2, 38, 39], the molecular mechanisms responsible for GSL-mediated cell functions are still unclear. One of the main issues centers around the association of GSLs with signal transducer molecules localized on the cytosolic side. However, we recently analyzed LacCer-enriched microdomains in human neutrophilic lineage cells [38]. LacCer, along with the Src family kinase Lyn, forms lipid microdomains on the plasma membranes of human neutrophils and is involved in several cellular functions, including chemotaxis, phagocytosis, and superoxide generation, highly dependent on Lyn [16, 29, 38]. HL-60 cells differentiated into neutrophilic lineage cells by DMSO (D-HL-60) were found to acquire superoxide generating activity, but not through LacCer, despite their expression of LacCer on plasma membranes [38]. Most LacCer and Lyn were recovered in the microdomain fractions of neutrophils and D-HL-60 cells. Lipidomics analysis revealed that LacCer in the neutrophil plasma membrane was mainly composed of molecular species containing C16:0, C24:1, and C24:0 fatty acid chains, whereas over 70% of LacCer in the plasma membranes of D-HL-60 cells contained C16:0 fatty acid chains, but only about 14% were C24:1 and C24:0 [11]. Lyn was immunoprecipitated by anti-LacCer antibody in neutrophils but not D-HL-60 cells. Importantly, Lyn was coimmunoprecipitated by anti-LacCer antibody from the detergent resistant membrane (DRM) fraction of plasma membranes from C24:0 and C24:1, but not C16:0 or C22:0, LacCer-loaded D-HL-60 cells. Anti-LacCer antibody induced superoxide generation from D-HL-60 cells loaded with C24:0-LacCer, but not C16:0-LacCer. Lyn colocalized with LacCer-enriched domains of D-HL-60 cells loaded with C24:0-LacCer, but not C16:0-LacCer. These results suggested that the C24 fatty acid chain of LacCer is indispensable for connecting Lyn with LacCer-enriched microdomains. Knockdown of Lyn molecules by human Lyn-specific short interfering RNA (siRNA) in D-HL-60 cells completely abolished the effects of C24:1-LacCer loading function [11], suggesting that Lyn is crucial for C24-LacCer-mediated neutrophil function. Experiments using azide-photoactivatable tritium-labeled C24- and C16-LacCer revealed that C24- but not C16-LacCer directly associated with Lyn and a heterotrimeric G protein subunit Gαi. These results confirm a specific direct interaction between C24-LacCer and the signal transduction molecules Lyn and Gαi, which are associated with the cytoplasmic layer via palmitic acid chains (Figure 2). LacCer species with very long fatty acids are indispensable for Lyn-coupled LacCer-enriched membrane microdomain-mediated neutrophil functions.

Bottom Line: These observations suggest that the very long fatty acid chains of ceramide are critical for GSL-mediated outside-in signaling.Sphingosine is another component of ceramide, with the hydrolysis of ceramide by ceramidase producing sphingosine and fatty acids.Sphingosine is phosphorylated by sphingosine kinase to sphingosine-1-phosphate, which is involved in a wide range of cellular functions, including growth, differentiation, survival, chemotaxis, angiogenesis, and embryogenesis, in various types of cells.

View Article: PubMed Central - PubMed

Affiliation: Institute for Environmental and Gender-Specific Medicine, Juntendo University Graduate School of Medicine, 2-1-1 Tomioka Urayasu, Chiba 2790021, Japan ; Infection Control Nursing, Juntendo University Graduate School of Health Care and Nursing, Chiba 2790023, Japan ; Laboratory of Biochemistry, Juntendo University School of Health Care and Nursing, Chiba 2790023, Japan.

ABSTRACT
Glycosphingolipids (GSLs) are composed of hydrophobic ceramide and hydrophilic sugar chains. GSLs cluster to form membrane microdomains (lipid rafts) on plasma membranes, along with several kinds of transducer molecules, including Src family kinases and small G proteins. However, GSL-mediated biological functions remain unclear. Lactosylceramide (LacCer, CDw17) is highly expressed on the plasma membranes of human phagocytes and mediates several immunological and inflammatory reactions, including phagocytosis, chemotaxis, and superoxide generation. LacCer forms membrane microdomains with the Src family tyrosine kinase Lyn and the Gαi subunit of heterotrimeric G proteins. The very long fatty acids C24:0 and C24:1 are the main ceramide components of LacCer in neutrophil plasma membranes and are directly connected with the fatty acids of Lyn and Gαi. These observations suggest that the very long fatty acid chains of ceramide are critical for GSL-mediated outside-in signaling. Sphingosine is another component of ceramide, with the hydrolysis of ceramide by ceramidase producing sphingosine and fatty acids. Sphingosine is phosphorylated by sphingosine kinase to sphingosine-1-phosphate, which is involved in a wide range of cellular functions, including growth, differentiation, survival, chemotaxis, angiogenesis, and embryogenesis, in various types of cells. This review describes the role of ceramide moiety of GSLs and its metabolites in immunological and inflammatory reactions in human.

No MeSH data available.


Related in: MedlinePlus