NK cells interact with the HLA-E molecule via the inhibitory receptor NKG2A and the activating re... more NK cells interact with the HLA-E molecule via the inhibitory receptor NKG2A and the activating receptor NKG2C. Hence, HLA-E can have a dual role in the immune response. In the present study, we aim to investigate the functional consequences of HLA-E for NKG2A and NKG2C expressing NK cell subsets by using a panel of HLA-E binding peptides derived from CMV, Hsp60 and HLA class I. PBMC derived from healthy subjects were used as targets for isolated NK cells and NK cell activation was examined by analysis of the expression of the degranulation marker CD107a. Peptide induced HLA-E expression inhibited degranulation of NKG2A+ NK cell subsets with almost all peptides, whereas NKG2A- NKG2C+ NK cell responses were enhanced only after incubation with four peptides; 1.3-fold with CMV(I), A80 and B13 and 3.2-fold with HLA-G derived peptide. In addition, the HLA-E:G peptide complex triggered NKG2C receptor internalization, as evidenced by reduction in the percentage of NKG2C+ NK cells when incubated with the peptide, which could be restored by addition of Bafilomycin. in contrast to NKG2A, NKG2C is regulated by HLA-E only when HLA-E is in complex with a restricted peptide repertoire, especially in combination with the HLA-G leader peptide.
We report the cloning of a Heterodera glycines cDNA that has 72% identity at the amino acid level... more We report the cloning of a Heterodera glycines cDNA that has 72% identity at the amino acid level to a pectate lyase from Globodera rostochiensis. In situ hybridizations showed that the corresponding gene (Hg-pel-1) is expressed in the subventral esophageal gland cells of second-stage juveniles. The deduced amino acid sequence of the H. glycines cDNA shows homology to class III pectate lyases of bacterial and fungal origin.
The prevalence of the metabolic syndrome and underlying metabolic disturbances increase rapidly i... more The prevalence of the metabolic syndrome and underlying metabolic disturbances increase rapidly in developed countries. Various molecular targets are currently under investigation to unravel the molecular mechanisms that cause these disturbances. This is done in attempt to counter or prevent the negative health consequences of the metabolic disturbances. Here, we reviewed the current knowledge on the role of C/EBP-β in these metabolic disturbances. C/EBP-β deletion in mice resulted in downregulation of hepatic lipogenic genes and increased expression of β-oxidation genes in brown adipose tissue. Furthermore, C/EBP-β is important in the differentiation and maturation of adipocytes and is increased during ER stress and proinflammatory conditions. So far, studies were only conducted in animals and in cell systems. The results found that C/EBP-β is an important transcription factor within the metabolic disturbances of the metabolic system. Therefore, it is interesting to examine the pot...
We report the cloning of a Heterodera glycines cDNA that has 72% identity at the amino acid level... more We report the cloning of a Heterodera glycines cDNA that has 72% identity at the amino acid level to a pectate lyase from Globodera rostochiensis. In situ hybridizations showed that the corresponding gene (Hg-pel-1) is expressed in the subventral esophageal gland cells of second-stage juveniles. The deduced amino acid sequence of the H. glycines cDNA shows homology to class III pectate lyases of bacterial and fungal origin.
Human Leukocyte Antigen (HLA)-E is a low-polymorphic non-classical HLA class I molecule which pla... more Human Leukocyte Antigen (HLA)-E is a low-polymorphic non-classical HLA class I molecule which plays a crucial role in immune surveillance by presentation of peptides to T and natural killer (NK) cells. HLA-E polymorphism is related to HLA-E surface expression and is associated with patient outcome after stem cell transplantation. We aim to investigate the regulation of HLA-E expression level in peripheral blood mononuclear cells (PBMCs) of healthy individuals homozygous for HLA-E*01:01 or HLA-E*01:03, by using a panel of HLA-E binding peptides derived from CMV, Hsp60 and HLA class I. Basal and peptide-induced HLA-E surface expression levels were higher in PBMC from HLA-E*01:03 homozygous subjects as compared to PBMC from HLA-E*01:01 homozygous subjects. HLA-E mRNA levels were comparable between the two genotypes and remained constant after peptide stimulation. HLA-E surface expression seemed to be not only dependent on the HLA-E genotype, but also on the sequence of the peptide as evidenced by the profound difference in HLA-E upregulation with the Hsp60 and the B7 peptide. Our results showed that peptide-induced HLA-E expression is regulated at the posttranscriptional level as extracellular peptide stimulation did not influence RNA expression. This study provides new insights in the mechanism by which HLA-E expression is regulated and underlines a new role for extracellular peptides in inducing HLA-E translation, which may represent a defense mechanism against lytic viral infections and necrosis.
Abstract
Scope: Fatty acids regulate PPAR activity, however, most studies evaluated the binding ... more Abstract Scope: Fatty acids regulate PPAR activity, however, most studies evaluated the binding ability of fatty acids to PPAR, which does not necessarily results in PPAR transactivation. We therefore examined dose-response relationships between fatty acids and PPAR transactivation in HepG2 cells. Secretion of apoA-I protein as-well-as CPT1, ACO, and PPAR mRNA expression, all accepted PPAR targets, were determined as read-outs. Methods and results: HepG2 cells transfected with full-length human PPAR and a PPRE luciferase reporter were exposed to different fatty acid concentrations. Lauric and lower doses of myristic acid increased PPAR transactivation. Palmitic and stearic acid inhibited and their monounsaturated counterparts palmitoleic and oleic acid increased PPAR transactivation. Linoleic and γ-linolenic acid did not influence PPAR transactivation, while α-linolenic acid strongly increased transactivation. Arachidonic, eicosapentaenoic (EPA), and docosahexaenoic (DHA) acid all activated PPAR transactivation at lower doses, but acted at higher concentrations as PPAR repressors. In line with these results, α-linolenic acid increased and DHA decreased apoA-I protein secretion and PPAR mRNA expression. Interestingly, ACO mRNA expression did not change while CPT1 mRNA expression showed the opposite pattern. Conclusion: Fatty acids, reported to bind to PPARα, could even repress PPARα transactivation though results may vary gene dependently illustrating involvement of multiple regulatory factors.
NK cells interact with the HLA-E molecule via the inhibitory receptor NKG2A and the activating re... more NK cells interact with the HLA-E molecule via the inhibitory receptor NKG2A and the activating receptor NKG2C. Hence, HLA-E can have a dual role in the immune response. In the present study, we aim to investigate the functional consequences of HLA-E for NKG2A and NKG2C expressing NK cell subsets by using a panel of HLA-E binding peptides derived from CMV, Hsp60 and HLA class I. PBMC derived from healthy subjects were used as targets for isolated NK cells and NK cell activation was examined by analysis of the expression of the degranulation marker CD107a. Peptide induced HLA-E expression inhibited degranulation of NKG2A+ NK cell subsets with almost all peptides, whereas NKG2A- NKG2C+ NK cell responses were enhanced only after incubation with four peptides; 1.3-fold with CMV(I), A80 and B13 and 3.2-fold with HLA-G derived peptide. In addition, the HLA-E:G peptide complex triggered NKG2C receptor internalization, as evidenced by reduction in the percentage of NKG2C+ NK cells when incubated with the peptide, which could be restored by addition of Bafilomycin. in contrast to NKG2A, NKG2C is regulated by HLA-E only when HLA-E is in complex with a restricted peptide repertoire, especially in combination with the HLA-G leader peptide.
We report the cloning of a Heterodera glycines cDNA that has 72% identity at the amino acid level... more We report the cloning of a Heterodera glycines cDNA that has 72% identity at the amino acid level to a pectate lyase from Globodera rostochiensis. In situ hybridizations showed that the corresponding gene (Hg-pel-1) is expressed in the subventral esophageal gland cells of second-stage juveniles. The deduced amino acid sequence of the H. glycines cDNA shows homology to class III pectate lyases of bacterial and fungal origin.
The prevalence of the metabolic syndrome and underlying metabolic disturbances increase rapidly i... more The prevalence of the metabolic syndrome and underlying metabolic disturbances increase rapidly in developed countries. Various molecular targets are currently under investigation to unravel the molecular mechanisms that cause these disturbances. This is done in attempt to counter or prevent the negative health consequences of the metabolic disturbances. Here, we reviewed the current knowledge on the role of C/EBP-β in these metabolic disturbances. C/EBP-β deletion in mice resulted in downregulation of hepatic lipogenic genes and increased expression of β-oxidation genes in brown adipose tissue. Furthermore, C/EBP-β is important in the differentiation and maturation of adipocytes and is increased during ER stress and proinflammatory conditions. So far, studies were only conducted in animals and in cell systems. The results found that C/EBP-β is an important transcription factor within the metabolic disturbances of the metabolic system. Therefore, it is interesting to examine the pot...
We report the cloning of a Heterodera glycines cDNA that has 72% identity at the amino acid level... more We report the cloning of a Heterodera glycines cDNA that has 72% identity at the amino acid level to a pectate lyase from Globodera rostochiensis. In situ hybridizations showed that the corresponding gene (Hg-pel-1) is expressed in the subventral esophageal gland cells of second-stage juveniles. The deduced amino acid sequence of the H. glycines cDNA shows homology to class III pectate lyases of bacterial and fungal origin.
Human Leukocyte Antigen (HLA)-E is a low-polymorphic non-classical HLA class I molecule which pla... more Human Leukocyte Antigen (HLA)-E is a low-polymorphic non-classical HLA class I molecule which plays a crucial role in immune surveillance by presentation of peptides to T and natural killer (NK) cells. HLA-E polymorphism is related to HLA-E surface expression and is associated with patient outcome after stem cell transplantation. We aim to investigate the regulation of HLA-E expression level in peripheral blood mononuclear cells (PBMCs) of healthy individuals homozygous for HLA-E*01:01 or HLA-E*01:03, by using a panel of HLA-E binding peptides derived from CMV, Hsp60 and HLA class I. Basal and peptide-induced HLA-E surface expression levels were higher in PBMC from HLA-E*01:03 homozygous subjects as compared to PBMC from HLA-E*01:01 homozygous subjects. HLA-E mRNA levels were comparable between the two genotypes and remained constant after peptide stimulation. HLA-E surface expression seemed to be not only dependent on the HLA-E genotype, but also on the sequence of the peptide as evidenced by the profound difference in HLA-E upregulation with the Hsp60 and the B7 peptide. Our results showed that peptide-induced HLA-E expression is regulated at the posttranscriptional level as extracellular peptide stimulation did not influence RNA expression. This study provides new insights in the mechanism by which HLA-E expression is regulated and underlines a new role for extracellular peptides in inducing HLA-E translation, which may represent a defense mechanism against lytic viral infections and necrosis.
Abstract
Scope: Fatty acids regulate PPAR activity, however, most studies evaluated the binding ... more Abstract Scope: Fatty acids regulate PPAR activity, however, most studies evaluated the binding ability of fatty acids to PPAR, which does not necessarily results in PPAR transactivation. We therefore examined dose-response relationships between fatty acids and PPAR transactivation in HepG2 cells. Secretion of apoA-I protein as-well-as CPT1, ACO, and PPAR mRNA expression, all accepted PPAR targets, were determined as read-outs. Methods and results: HepG2 cells transfected with full-length human PPAR and a PPRE luciferase reporter were exposed to different fatty acid concentrations. Lauric and lower doses of myristic acid increased PPAR transactivation. Palmitic and stearic acid inhibited and their monounsaturated counterparts palmitoleic and oleic acid increased PPAR transactivation. Linoleic and γ-linolenic acid did not influence PPAR transactivation, while α-linolenic acid strongly increased transactivation. Arachidonic, eicosapentaenoic (EPA), and docosahexaenoic (DHA) acid all activated PPAR transactivation at lower doses, but acted at higher concentrations as PPAR repressors. In line with these results, α-linolenic acid increased and DHA decreased apoA-I protein secretion and PPAR mRNA expression. Interestingly, ACO mRNA expression did not change while CPT1 mRNA expression showed the opposite pattern. Conclusion: Fatty acids, reported to bind to PPARα, could even repress PPARα transactivation though results may vary gene dependently illustrating involvement of multiple regulatory factors.
Uploads
Scope: Fatty acids regulate PPAR activity, however, most studies evaluated the binding ability of fatty acids to PPAR, which does not necessarily results in PPAR transactivation. We therefore examined dose-response relationships between fatty acids and PPAR transactivation in HepG2 cells. Secretion of apoA-I protein as-well-as CPT1, ACO, and PPAR mRNA expression, all accepted PPAR targets, were determined as read-outs.
Methods and results: HepG2 cells transfected with full-length human PPAR and a PPRE luciferase reporter were exposed to different fatty acid concentrations. Lauric and lower doses of myristic acid increased PPAR transactivation. Palmitic and stearic acid inhibited and their monounsaturated counterparts palmitoleic and oleic acid increased PPAR transactivation. Linoleic and γ-linolenic acid did not influence PPAR transactivation, while α-linolenic acid strongly increased transactivation. Arachidonic, eicosapentaenoic (EPA), and docosahexaenoic (DHA) acid all activated PPAR transactivation at lower doses, but acted at higher concentrations as PPAR repressors. In line with these results, α-linolenic acid increased and DHA decreased apoA-I protein secretion and PPAR mRNA expression. Interestingly, ACO mRNA expression did not change while CPT1 mRNA expression showed the opposite pattern.
Conclusion: Fatty acids, reported to bind to PPARα, could even repress PPARα transactivation though results may vary gene dependently illustrating involvement of multiple regulatory factors.
Scope: Fatty acids regulate PPAR activity, however, most studies evaluated the binding ability of fatty acids to PPAR, which does not necessarily results in PPAR transactivation. We therefore examined dose-response relationships between fatty acids and PPAR transactivation in HepG2 cells. Secretion of apoA-I protein as-well-as CPT1, ACO, and PPAR mRNA expression, all accepted PPAR targets, were determined as read-outs.
Methods and results: HepG2 cells transfected with full-length human PPAR and a PPRE luciferase reporter were exposed to different fatty acid concentrations. Lauric and lower doses of myristic acid increased PPAR transactivation. Palmitic and stearic acid inhibited and their monounsaturated counterparts palmitoleic and oleic acid increased PPAR transactivation. Linoleic and γ-linolenic acid did not influence PPAR transactivation, while α-linolenic acid strongly increased transactivation. Arachidonic, eicosapentaenoic (EPA), and docosahexaenoic (DHA) acid all activated PPAR transactivation at lower doses, but acted at higher concentrations as PPAR repressors. In line with these results, α-linolenic acid increased and DHA decreased apoA-I protein secretion and PPAR mRNA expression. Interestingly, ACO mRNA expression did not change while CPT1 mRNA expression showed the opposite pattern.
Conclusion: Fatty acids, reported to bind to PPARα, could even repress PPARα transactivation though results may vary gene dependently illustrating involvement of multiple regulatory factors.