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OSP/claudin-11 forms a complex with a novel member of the tetraspanin super family and beta1 integrin and regulates proliferation and migration of oligodendrocytes.

Tiwari-Woodruff SK, Buznikov AG, Vu TQ, Micevych PE, Chen K, Kornblum HI, Bronstein JM - J. Cell Biol. (2001)

Bottom Line: Overexpression of OSP/claudin-11 or OAP-1 induced proliferation in an oligodendrocyte cell line.Anti-OAP-1, anti-OSP/claudin-11, and anti-beta1 integrin antibodies inhibited migration of primary oligodendrocytes, and migration was impaired in OSP/claudin-11-deficient primary oligodendrocytes.These data suggest a role for OSP/claudin-11, OAP-1, and beta1 integrin complex in regulating proliferation and migration of oligodendrocytes, a process essential for normal myelination and repair.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, University of California at Los Angeles School of Medicine, Los Angeles, California 90095, USA.

ABSTRACT
Oligodendrocyte-specific protein (OSP)/claudin-11 is a major component of central nervous system myelin and forms tight junctions (TJs) within myelin sheaths. TJs are essential for forming a paracellular barrier and have been implicated in the regulation of growth and differentiation via signal transduction pathways. We have identified an OSP/claudin-11-associated protein (OAP)1, using a yeast two-hybrid screen. OAP-1 is a novel member of the tetraspanin superfamily, and it is widely expressed in several cell types, including oligodendrocytes. OAP-1, OSP/claudin-11, and beta1 integrin form a complex as indicated by coimmunoprecipitation and confocal immunocytochemistry. Overexpression of OSP/claudin-11 or OAP-1 induced proliferation in an oligodendrocyte cell line. Anti-OAP-1, anti-OSP/claudin-11, and anti-beta1 integrin antibodies inhibited migration of primary oligodendrocytes, and migration was impaired in OSP/claudin-11-deficient primary oligodendrocytes. These data suggest a role for OSP/claudin-11, OAP-1, and beta1 integrin complex in regulating proliferation and migration of oligodendrocytes, a process essential for normal myelination and repair.

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Oligodendrocyte migration in the presence of OSP/claudin-11, OAP-1, and β1 integrin antibodies and in OSP/claudin-11–deficient cells. (A) Cells were migrated out of agarose drops in medium: −control, minus fibronectin; +control, plus fibronectin; anti–β1 integrin antibody; anti–OSP/claudin-11 antibody; anti–OAP-1 antibody; boiled inactive anti–OAP-1 antibody, I anti–OAP-1; anti-GFAP antibody; GRGDSP peptide; and GRGESP peptide. Except for the −control, all other conditions contained fibronectin. The total number of cells migrating out of the agar drop was counted after 4 d. Statistical values represent each condition versus positive control: **P < 0.0005; *P < 0.005 (Student's t test). (B) Migration assays were performed using oligodendrocytes isolated from wild-type (+/+), heterozygous OSP (+/−), and homozygous knockout OSP (−/−) mice, and cells were allowed to migrate in the presence (black bars) and absence (stippled bars) of fibronectin. There was marked attenuation of fibronectin-dependent migration in OSP/claudin-11–deficient cells. Values are expressed as percentage of wild-type. Heterozygous (+/−) versus wild-type (*P < 0.05) and homozygous recessive (−/−) versus wild-type (**P < 0.005) (Student's t test).
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Figure 8: Oligodendrocyte migration in the presence of OSP/claudin-11, OAP-1, and β1 integrin antibodies and in OSP/claudin-11–deficient cells. (A) Cells were migrated out of agarose drops in medium: −control, minus fibronectin; +control, plus fibronectin; anti–β1 integrin antibody; anti–OSP/claudin-11 antibody; anti–OAP-1 antibody; boiled inactive anti–OAP-1 antibody, I anti–OAP-1; anti-GFAP antibody; GRGDSP peptide; and GRGESP peptide. Except for the −control, all other conditions contained fibronectin. The total number of cells migrating out of the agar drop was counted after 4 d. Statistical values represent each condition versus positive control: **P < 0.0005; *P < 0.005 (Student's t test). (B) Migration assays were performed using oligodendrocytes isolated from wild-type (+/+), heterozygous OSP (+/−), and homozygous knockout OSP (−/−) mice, and cells were allowed to migrate in the presence (black bars) and absence (stippled bars) of fibronectin. There was marked attenuation of fibronectin-dependent migration in OSP/claudin-11–deficient cells. Values are expressed as percentage of wild-type. Heterozygous (+/−) versus wild-type (*P < 0.05) and homozygous recessive (−/−) versus wild-type (**P < 0.005) (Student's t test).

Mentions: Cell proliferation, differentiation, and migration are at least partially mediated by the interaction between cell membrane proteins and extracellular matrix (ECM). Integrins are a key family of ECM receptors, and αvβ1 integrin has been shown to play a role in oligodendrocyte migration (Milner et al. 1996). Since OSP/claudin-11 and OAP-1 form a complex with β1 integrins, it is likely that they are involved in cellular interactions with ECM. The possible involvement of OSP/claudin-11 and OAP-1 in oligodendrocyte migration was tested using an established in vitro assay used previously to demonstrate that integrins are involved in oligodendrocyte migration (Varani et al. 1978; Milner et al. 1996). Primary oligodendrocytes were plated in an agarose drop in the presence (positive control) or absence (negative control) of fibronectin. Maximal migration in positive controls was achieved in 4 d, with 58 ± 12 cells per well appearing in the migratory zone. Migration of oligodendrocytes was inhibited significantly in the presence of anti–OSP/claudin-11, anti–OAP-1, and anti–β1 integrin antibodies by 95, 76, and 88% of the control, respectively (Fig. 8 A). The inhibitory effect of the antibodies on migration was specific, since inactive anti–OAP-1 (boiled for 10 min) and anti-GFAP (unrelated) antibody had no effect. Reduced migration also did not reflect decreased viability since >95% of all cells under all conditions remained viable as determined by trypan blue staining.


OSP/claudin-11 forms a complex with a novel member of the tetraspanin super family and beta1 integrin and regulates proliferation and migration of oligodendrocytes.

Tiwari-Woodruff SK, Buznikov AG, Vu TQ, Micevych PE, Chen K, Kornblum HI, Bronstein JM - J. Cell Biol. (2001)

Oligodendrocyte migration in the presence of OSP/claudin-11, OAP-1, and β1 integrin antibodies and in OSP/claudin-11–deficient cells. (A) Cells were migrated out of agarose drops in medium: −control, minus fibronectin; +control, plus fibronectin; anti–β1 integrin antibody; anti–OSP/claudin-11 antibody; anti–OAP-1 antibody; boiled inactive anti–OAP-1 antibody, I anti–OAP-1; anti-GFAP antibody; GRGDSP peptide; and GRGESP peptide. Except for the −control, all other conditions contained fibronectin. The total number of cells migrating out of the agar drop was counted after 4 d. Statistical values represent each condition versus positive control: **P < 0.0005; *P < 0.005 (Student's t test). (B) Migration assays were performed using oligodendrocytes isolated from wild-type (+/+), heterozygous OSP (+/−), and homozygous knockout OSP (−/−) mice, and cells were allowed to migrate in the presence (black bars) and absence (stippled bars) of fibronectin. There was marked attenuation of fibronectin-dependent migration in OSP/claudin-11–deficient cells. Values are expressed as percentage of wild-type. Heterozygous (+/−) versus wild-type (*P < 0.05) and homozygous recessive (−/−) versus wild-type (**P < 0.005) (Student's t test).
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Figure 8: Oligodendrocyte migration in the presence of OSP/claudin-11, OAP-1, and β1 integrin antibodies and in OSP/claudin-11–deficient cells. (A) Cells were migrated out of agarose drops in medium: −control, minus fibronectin; +control, plus fibronectin; anti–β1 integrin antibody; anti–OSP/claudin-11 antibody; anti–OAP-1 antibody; boiled inactive anti–OAP-1 antibody, I anti–OAP-1; anti-GFAP antibody; GRGDSP peptide; and GRGESP peptide. Except for the −control, all other conditions contained fibronectin. The total number of cells migrating out of the agar drop was counted after 4 d. Statistical values represent each condition versus positive control: **P < 0.0005; *P < 0.005 (Student's t test). (B) Migration assays were performed using oligodendrocytes isolated from wild-type (+/+), heterozygous OSP (+/−), and homozygous knockout OSP (−/−) mice, and cells were allowed to migrate in the presence (black bars) and absence (stippled bars) of fibronectin. There was marked attenuation of fibronectin-dependent migration in OSP/claudin-11–deficient cells. Values are expressed as percentage of wild-type. Heterozygous (+/−) versus wild-type (*P < 0.05) and homozygous recessive (−/−) versus wild-type (**P < 0.005) (Student's t test).
Mentions: Cell proliferation, differentiation, and migration are at least partially mediated by the interaction between cell membrane proteins and extracellular matrix (ECM). Integrins are a key family of ECM receptors, and αvβ1 integrin has been shown to play a role in oligodendrocyte migration (Milner et al. 1996). Since OSP/claudin-11 and OAP-1 form a complex with β1 integrins, it is likely that they are involved in cellular interactions with ECM. The possible involvement of OSP/claudin-11 and OAP-1 in oligodendrocyte migration was tested using an established in vitro assay used previously to demonstrate that integrins are involved in oligodendrocyte migration (Varani et al. 1978; Milner et al. 1996). Primary oligodendrocytes were plated in an agarose drop in the presence (positive control) or absence (negative control) of fibronectin. Maximal migration in positive controls was achieved in 4 d, with 58 ± 12 cells per well appearing in the migratory zone. Migration of oligodendrocytes was inhibited significantly in the presence of anti–OSP/claudin-11, anti–OAP-1, and anti–β1 integrin antibodies by 95, 76, and 88% of the control, respectively (Fig. 8 A). The inhibitory effect of the antibodies on migration was specific, since inactive anti–OAP-1 (boiled for 10 min) and anti-GFAP (unrelated) antibody had no effect. Reduced migration also did not reflect decreased viability since >95% of all cells under all conditions remained viable as determined by trypan blue staining.

Bottom Line: Overexpression of OSP/claudin-11 or OAP-1 induced proliferation in an oligodendrocyte cell line.Anti-OAP-1, anti-OSP/claudin-11, and anti-beta1 integrin antibodies inhibited migration of primary oligodendrocytes, and migration was impaired in OSP/claudin-11-deficient primary oligodendrocytes.These data suggest a role for OSP/claudin-11, OAP-1, and beta1 integrin complex in regulating proliferation and migration of oligodendrocytes, a process essential for normal myelination and repair.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, University of California at Los Angeles School of Medicine, Los Angeles, California 90095, USA.

ABSTRACT
Oligodendrocyte-specific protein (OSP)/claudin-11 is a major component of central nervous system myelin and forms tight junctions (TJs) within myelin sheaths. TJs are essential for forming a paracellular barrier and have been implicated in the regulation of growth and differentiation via signal transduction pathways. We have identified an OSP/claudin-11-associated protein (OAP)1, using a yeast two-hybrid screen. OAP-1 is a novel member of the tetraspanin superfamily, and it is widely expressed in several cell types, including oligodendrocytes. OAP-1, OSP/claudin-11, and beta1 integrin form a complex as indicated by coimmunoprecipitation and confocal immunocytochemistry. Overexpression of OSP/claudin-11 or OAP-1 induced proliferation in an oligodendrocyte cell line. Anti-OAP-1, anti-OSP/claudin-11, and anti-beta1 integrin antibodies inhibited migration of primary oligodendrocytes, and migration was impaired in OSP/claudin-11-deficient primary oligodendrocytes. These data suggest a role for OSP/claudin-11, OAP-1, and beta1 integrin complex in regulating proliferation and migration of oligodendrocytes, a process essential for normal myelination and repair.

Show MeSH
Related in: MedlinePlus