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Negative regulation of immunoglobulin E-dependent allergic responses by Lyn kinase.

Odom S, Gomez G, Kovarova M, Furumoto Y, Ryan JJ, Wright HV, Gonzalez-Espinosa C, Hibbs ML, Harder KW, Rivera J - J. Exp. Med. (2004)

Bottom Line: Contrary to this belief, Lyn kinase was found to have an important role as a negative regulator of the allergic response.This became apparent from the hyperresponsive degranulation of lyn-/- bone marrow-derived mast cells, which is driven by hyperactivation of Fyn kinase that occurs, in part, through the loss of negative regulation by COOH-terminal Src kinase (Csk) and the adaptor, Csk-binding protein.This was mirrored by increased circulating histamine, increased mast cell numbers, increased cell surface expression of the high affinity IgE receptor (FcepsilonRI), and eosinophilia.

View Article: PubMed Central - PubMed

Affiliation: Molecular Inflammation Section, Molecular Immunology and Inflammation Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA.

ABSTRACT
A role for Lyn kinase as a positive regulator of immunoglobulin (Ig)E-dependent allergy has long been accepted. Contrary to this belief, Lyn kinase was found to have an important role as a negative regulator of the allergic response. This became apparent from the hyperresponsive degranulation of lyn-/- bone marrow-derived mast cells, which is driven by hyperactivation of Fyn kinase that occurs, in part, through the loss of negative regulation by COOH-terminal Src kinase (Csk) and the adaptor, Csk-binding protein. This phenotype is recapitulated in vivo as young lyn-/- mice showed an enhanced anaphylactic response. In vivo studies also demonstrated that as lyn-/- mice aged, their serum IgE increased as well as occupancy of the high affinity IgE receptor (FcepsilonRI). This was mirrored by increased circulating histamine, increased mast cell numbers, increased cell surface expression of the high affinity IgE receptor (FcepsilonRI), and eosinophilia. The increased IgE production was not a consequence of increased Fyn kinase activity in lyn-/- mice because both lyn-/- and lyn-/- fyn-/- mice showed high IgE levels. Thus, lyn-/- mice and mast cells thereof show multiple allergy-associated traits, causing reconsideration of the possible efficacy in therapeutic targeting of Lyn in allergic disease.

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Lyn−/− mice show increased serum IgE, increased FcεRI occupancy, and increased circulating histamine. (a) The serum IgE of 4- or 7-wk-old age- and sex-matched unchallenged wt or lyn−/− mice was measured by ELISA. (b) FcεRI occupancy of peritoneal mast cells was determined from 4- or 7-wk-old wt and lyn−/− mice. The mean fluorescence intensity of cells before and after incubation with exogenous IgE was compared with obtained relative occupancies. Data is shown as a percentage of receptors available for binding of exogenous IgE. (c) Plasma histamine concentration of the mice in (a) was measured by competitive ELISA. (d) Correlation analysis of serum IgE and histamine concentrations from lyn−/− mice (data in a and c). Significance for all data was determined by an unpaired t test. ***, a p-value of ≤0.003; *, a p-value of ≤0.03. Pearson r2 = 0.9517 for (d). A total of five (b) or eight (a and c) mice were used.
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fig5: Lyn−/− mice show increased serum IgE, increased FcεRI occupancy, and increased circulating histamine. (a) The serum IgE of 4- or 7-wk-old age- and sex-matched unchallenged wt or lyn−/− mice was measured by ELISA. (b) FcεRI occupancy of peritoneal mast cells was determined from 4- or 7-wk-old wt and lyn−/− mice. The mean fluorescence intensity of cells before and after incubation with exogenous IgE was compared with obtained relative occupancies. Data is shown as a percentage of receptors available for binding of exogenous IgE. (c) Plasma histamine concentration of the mice in (a) was measured by competitive ELISA. (d) Correlation analysis of serum IgE and histamine concentrations from lyn−/− mice (data in a and c). Significance for all data was determined by an unpaired t test. ***, a p-value of ≤0.003; *, a p-value of ≤0.03. Pearson r2 = 0.9517 for (d). A total of five (b) or eight (a and c) mice were used.

Mentions: The decreased anaphylactic response of older lyn−/− mice led us to explore the apparent discrepancy with the observed BMMC hyperresponsiveness in our in vitro studies as well as with increased in vivo anaphylactic response of young mice. The most logical explanation is that the occupancy of FcεRI by IgE would increase with the age of the mice based on the observation that lyn−/− mice were shown to have increased levels of Igs and enhanced IL-4–dependent Ig class switching leading to IgE (5, 6, 25). Increased IgE production might preclude sensitization with Ag-specific IgE. Thus, we first explored the relationship between the serum IgE levels of lyn−/− mice and the age of the mice. As shown in Fig. 5 a, young lyn−/− mice (4 wk of age) showed no significant difference in circulating IgE levels when compared with wild-type mice of up to 16 wk of age (0.23 ± 0.04 vs. 0.31 ± 0.05 μg/ml), although a slight trend toward increased levels of IgE was noted. However, by 7 wk of age, lyn−/− mice showed as much as a 10-fold increase in serum IgE levels ranging from 0.98 to 5.8 μg/ml when compared with 7-wk-old wild-type mice (0.14–1.2 μg/ml). This suggested the possibility that as lyn−/− mice aged, FcεRI occupancy might vary from wild-type mice. Fig. 5 b shows that FcεRI occupancy of peritoneal mast cells by IgE increases with age for both wild-type and lyn−/− mice. However, by 4 wk of age, lyn−/− mice show FcεRI occupancy levels similar to that of 7-wk-old wild-type mice. By 7 wk of age, the FcεRI occupancy of lyn−/− mice by IgE is almost complete. By 12–16 wk, lyn−/− mice have no unoccupied FcεRI (not depicted). Although wild-type mice at 7 wk showed an average of 22% of their mast cell FcεRI as available for IgE binding, only 4% of these receptors are available in lyn−/− mice. Interestingly, wild-type mice of 16 wk of age showed an FcεRI occupancy of ∼86%. Nonetheless, these mice respond to a PSA challenge similarly to younger mice (not depicted), suggesting that to respond to Ag-specific IgE, >4% but as little as 14% of the receptor occupied by this IgE is required. This level of FcεRI availability for Ag-specific IgE is still seen in 4-wk-old lyn−/− mice, but not after 7 wk of age (Fig. 5 b).


Negative regulation of immunoglobulin E-dependent allergic responses by Lyn kinase.

Odom S, Gomez G, Kovarova M, Furumoto Y, Ryan JJ, Wright HV, Gonzalez-Espinosa C, Hibbs ML, Harder KW, Rivera J - J. Exp. Med. (2004)

Lyn−/− mice show increased serum IgE, increased FcεRI occupancy, and increased circulating histamine. (a) The serum IgE of 4- or 7-wk-old age- and sex-matched unchallenged wt or lyn−/− mice was measured by ELISA. (b) FcεRI occupancy of peritoneal mast cells was determined from 4- or 7-wk-old wt and lyn−/− mice. The mean fluorescence intensity of cells before and after incubation with exogenous IgE was compared with obtained relative occupancies. Data is shown as a percentage of receptors available for binding of exogenous IgE. (c) Plasma histamine concentration of the mice in (a) was measured by competitive ELISA. (d) Correlation analysis of serum IgE and histamine concentrations from lyn−/− mice (data in a and c). Significance for all data was determined by an unpaired t test. ***, a p-value of ≤0.003; *, a p-value of ≤0.03. Pearson r2 = 0.9517 for (d). A total of five (b) or eight (a and c) mice were used.
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Related In: Results  -  Collection

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fig5: Lyn−/− mice show increased serum IgE, increased FcεRI occupancy, and increased circulating histamine. (a) The serum IgE of 4- or 7-wk-old age- and sex-matched unchallenged wt or lyn−/− mice was measured by ELISA. (b) FcεRI occupancy of peritoneal mast cells was determined from 4- or 7-wk-old wt and lyn−/− mice. The mean fluorescence intensity of cells before and after incubation with exogenous IgE was compared with obtained relative occupancies. Data is shown as a percentage of receptors available for binding of exogenous IgE. (c) Plasma histamine concentration of the mice in (a) was measured by competitive ELISA. (d) Correlation analysis of serum IgE and histamine concentrations from lyn−/− mice (data in a and c). Significance for all data was determined by an unpaired t test. ***, a p-value of ≤0.003; *, a p-value of ≤0.03. Pearson r2 = 0.9517 for (d). A total of five (b) or eight (a and c) mice were used.
Mentions: The decreased anaphylactic response of older lyn−/− mice led us to explore the apparent discrepancy with the observed BMMC hyperresponsiveness in our in vitro studies as well as with increased in vivo anaphylactic response of young mice. The most logical explanation is that the occupancy of FcεRI by IgE would increase with the age of the mice based on the observation that lyn−/− mice were shown to have increased levels of Igs and enhanced IL-4–dependent Ig class switching leading to IgE (5, 6, 25). Increased IgE production might preclude sensitization with Ag-specific IgE. Thus, we first explored the relationship between the serum IgE levels of lyn−/− mice and the age of the mice. As shown in Fig. 5 a, young lyn−/− mice (4 wk of age) showed no significant difference in circulating IgE levels when compared with wild-type mice of up to 16 wk of age (0.23 ± 0.04 vs. 0.31 ± 0.05 μg/ml), although a slight trend toward increased levels of IgE was noted. However, by 7 wk of age, lyn−/− mice showed as much as a 10-fold increase in serum IgE levels ranging from 0.98 to 5.8 μg/ml when compared with 7-wk-old wild-type mice (0.14–1.2 μg/ml). This suggested the possibility that as lyn−/− mice aged, FcεRI occupancy might vary from wild-type mice. Fig. 5 b shows that FcεRI occupancy of peritoneal mast cells by IgE increases with age for both wild-type and lyn−/− mice. However, by 4 wk of age, lyn−/− mice show FcεRI occupancy levels similar to that of 7-wk-old wild-type mice. By 7 wk of age, the FcεRI occupancy of lyn−/− mice by IgE is almost complete. By 12–16 wk, lyn−/− mice have no unoccupied FcεRI (not depicted). Although wild-type mice at 7 wk showed an average of 22% of their mast cell FcεRI as available for IgE binding, only 4% of these receptors are available in lyn−/− mice. Interestingly, wild-type mice of 16 wk of age showed an FcεRI occupancy of ∼86%. Nonetheless, these mice respond to a PSA challenge similarly to younger mice (not depicted), suggesting that to respond to Ag-specific IgE, >4% but as little as 14% of the receptor occupied by this IgE is required. This level of FcεRI availability for Ag-specific IgE is still seen in 4-wk-old lyn−/− mice, but not after 7 wk of age (Fig. 5 b).

Bottom Line: Contrary to this belief, Lyn kinase was found to have an important role as a negative regulator of the allergic response.This became apparent from the hyperresponsive degranulation of lyn-/- bone marrow-derived mast cells, which is driven by hyperactivation of Fyn kinase that occurs, in part, through the loss of negative regulation by COOH-terminal Src kinase (Csk) and the adaptor, Csk-binding protein.This was mirrored by increased circulating histamine, increased mast cell numbers, increased cell surface expression of the high affinity IgE receptor (FcepsilonRI), and eosinophilia.

View Article: PubMed Central - PubMed

Affiliation: Molecular Inflammation Section, Molecular Immunology and Inflammation Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA.

ABSTRACT
A role for Lyn kinase as a positive regulator of immunoglobulin (Ig)E-dependent allergy has long been accepted. Contrary to this belief, Lyn kinase was found to have an important role as a negative regulator of the allergic response. This became apparent from the hyperresponsive degranulation of lyn-/- bone marrow-derived mast cells, which is driven by hyperactivation of Fyn kinase that occurs, in part, through the loss of negative regulation by COOH-terminal Src kinase (Csk) and the adaptor, Csk-binding protein. This phenotype is recapitulated in vivo as young lyn-/- mice showed an enhanced anaphylactic response. In vivo studies also demonstrated that as lyn-/- mice aged, their serum IgE increased as well as occupancy of the high affinity IgE receptor (FcepsilonRI). This was mirrored by increased circulating histamine, increased mast cell numbers, increased cell surface expression of the high affinity IgE receptor (FcepsilonRI), and eosinophilia. The increased IgE production was not a consequence of increased Fyn kinase activity in lyn-/- mice because both lyn-/- and lyn-/- fyn-/- mice showed high IgE levels. Thus, lyn-/- mice and mast cells thereof show multiple allergy-associated traits, causing reconsideration of the possible efficacy in therapeutic targeting of Lyn in allergic disease.

Show MeSH
Related in: MedlinePlus