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LIGHT/TNFSF14 is increased in patients with type 2 diabetes mellitus and promotes islet cell dysfunction and endothelial cell inflammation in vitro

View Article: PubMed Central - PubMed

ABSTRACT

Aims/hypothesis: Activation of inflammatory pathways is involved in the pathogenesis of type 2 diabetes mellitus. On the basis of its role in vascular inflammation and in metabolic disorders, we hypothesised that the TNF superfamily (TNFSF) member 14 (LIGHT/TNFSF14) could be involved in the pathogenesis of type 2 diabetes mellitus.

Methods: Plasma levels of LIGHT were measured in two cohorts of type 2 diabetes mellitus patients (191 Italian and 40 Norwegian). Human pancreatic islet cells and arterial endothelial cells were used to explore regulation and relevant effects of LIGHT in vitro.

Results: Our major findings were: (1) in both diabetic cohorts, plasma levels of LIGHT were significantly raised compared with sex- and age-matched healthy controls (n = 32); (2) enhanced release from activated platelets seems to be an important contributor to the raised LIGHT levels in type 2 diabetes mellitus; (3) in human pancreatic islet cells, inflammatory cytokines increased the release of LIGHT and upregulated mRNA and protein levels of the LIGHT receptors lymphotoxin β receptor (LTβR) and TNF receptor superfamily member 14 (HVEM/TNFRSF14); (4) in these cells, LIGHT attenuated the insulin release in response to high glucose at least partly via pro-apoptotic effects; and (5) in human arterial endothelial cells, glucose boosted inflammatory response to LIGHT, accompanied by an upregulation of mRNA levels of HVEM (also known as TNFRSF14) and LTβR (also known as LTBR).

Conclusions/interpretation: Our findings show that patients with type 2 diabetes mellitus are characterised by increased plasma LIGHT levels. Our in vitro findings suggest that LIGHT may contribute to the progression of type 2 diabetes mellitus by attenuating insulin secretion in pancreatic islet cells and by contributing to vascular inflammation.

Electronic supplementary material: The online version of this article (doi:10.1007/s00125-016-4036-y) contains peer-reviewed but unedited supplementary material, which is available to authorised users.

No MeSH data available.


Related in: MedlinePlus

Proinflammatory stimuli increase the expression of LIGHT in human islets. Islets from independent preparations were stimulated for 24 h (a, b) or 48 h (c) with (black bars) or without (white bars) a PIC (IL-1β [1 ng/ml], IFN-γ [50 ng/ml], and TNF [10 ng/ml]) before the levels of LIGHT (ng/ml) were determined by ELISA in cell supernatant fractions (a). (b) Expression of the LIGHT receptors (LTβR and HVEM) and LIGHT mRNA levels as assessed by quantitative PCR in relation to the control gene β actin. (c) Protein levels of the LIGHT receptors in relation to the protein expression levels of GAPDH as assessed by western blotting. Data are presented as mean ± SEM (n = 3–6). *p < 0.05 and **p < 0.01 vs unstimulated cells using a Mann–Whitney U test. Unstim, unstimulated
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Fig3: Proinflammatory stimuli increase the expression of LIGHT in human islets. Islets from independent preparations were stimulated for 24 h (a, b) or 48 h (c) with (black bars) or without (white bars) a PIC (IL-1β [1 ng/ml], IFN-γ [50 ng/ml], and TNF [10 ng/ml]) before the levels of LIGHT (ng/ml) were determined by ELISA in cell supernatant fractions (a). (b) Expression of the LIGHT receptors (LTβR and HVEM) and LIGHT mRNA levels as assessed by quantitative PCR in relation to the control gene β actin. (c) Protein levels of the LIGHT receptors in relation to the protein expression levels of GAPDH as assessed by western blotting. Data are presented as mean ± SEM (n = 3–6). *p < 0.05 and **p < 0.01 vs unstimulated cells using a Mann–Whitney U test. Unstim, unstimulated

Mentions: To further elucidate the association of LIGHT with type 2 diabetes mellitus, we examined the regulation and effects of LIGHT in human pancreatic islet cells. Inflammation, and in particular IL-1β, has been implicated in the pathogenesis of beta cell dysfunction in type 2 diabetes mellitus [3, 18]. Therefore, the cells were co-stimulated with a proinflammatory cytokine cocktail (PIC) of IL-1β (10 ng/ml), TNF (10 ng/ml) and IFN-γ (50 ng/ml) (see ESM Methods). This mixture of inflammatory stimuli significantly enhanced the release of LIGHT into cell supernatant fractions and markedly upregulated the mRNA levels of the two LIGHT receptors HVEM (also known as TNFRSF14) and LTβR (also known as LTBR) without any significant effect on LIGHT (also known as TNFSF14) mRNA levels after culturing for 24 h (Fig. 3a, b). This increase in HVEM and LTβR expression in PIC-exposed islets was also seen at the protein level, as determined by western blotting (Fig. 3c).Fig. 3


LIGHT/TNFSF14 is increased in patients with type 2 diabetes mellitus and promotes islet cell dysfunction and endothelial cell inflammation in vitro
Proinflammatory stimuli increase the expression of LIGHT in human islets. Islets from independent preparations were stimulated for 24 h (a, b) or 48 h (c) with (black bars) or without (white bars) a PIC (IL-1β [1 ng/ml], IFN-γ [50 ng/ml], and TNF [10 ng/ml]) before the levels of LIGHT (ng/ml) were determined by ELISA in cell supernatant fractions (a). (b) Expression of the LIGHT receptors (LTβR and HVEM) and LIGHT mRNA levels as assessed by quantitative PCR in relation to the control gene β actin. (c) Protein levels of the LIGHT receptors in relation to the protein expression levels of GAPDH as assessed by western blotting. Data are presented as mean ± SEM (n = 3–6). *p < 0.05 and **p < 0.01 vs unstimulated cells using a Mann–Whitney U test. Unstim, unstimulated
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Fig3: Proinflammatory stimuli increase the expression of LIGHT in human islets. Islets from independent preparations were stimulated for 24 h (a, b) or 48 h (c) with (black bars) or without (white bars) a PIC (IL-1β [1 ng/ml], IFN-γ [50 ng/ml], and TNF [10 ng/ml]) before the levels of LIGHT (ng/ml) were determined by ELISA in cell supernatant fractions (a). (b) Expression of the LIGHT receptors (LTβR and HVEM) and LIGHT mRNA levels as assessed by quantitative PCR in relation to the control gene β actin. (c) Protein levels of the LIGHT receptors in relation to the protein expression levels of GAPDH as assessed by western blotting. Data are presented as mean ± SEM (n = 3–6). *p < 0.05 and **p < 0.01 vs unstimulated cells using a Mann–Whitney U test. Unstim, unstimulated
Mentions: To further elucidate the association of LIGHT with type 2 diabetes mellitus, we examined the regulation and effects of LIGHT in human pancreatic islet cells. Inflammation, and in particular IL-1β, has been implicated in the pathogenesis of beta cell dysfunction in type 2 diabetes mellitus [3, 18]. Therefore, the cells were co-stimulated with a proinflammatory cytokine cocktail (PIC) of IL-1β (10 ng/ml), TNF (10 ng/ml) and IFN-γ (50 ng/ml) (see ESM Methods). This mixture of inflammatory stimuli significantly enhanced the release of LIGHT into cell supernatant fractions and markedly upregulated the mRNA levels of the two LIGHT receptors HVEM (also known as TNFRSF14) and LTβR (also known as LTBR) without any significant effect on LIGHT (also known as TNFSF14) mRNA levels after culturing for 24 h (Fig. 3a, b). This increase in HVEM and LTβR expression in PIC-exposed islets was also seen at the protein level, as determined by western blotting (Fig. 3c).Fig. 3

View Article: PubMed Central - PubMed

ABSTRACT

Aims/hypothesis: Activation of inflammatory pathways is involved in the pathogenesis of type 2 diabetes mellitus. On the basis of its role in vascular inflammation and in metabolic disorders, we hypothesised that the TNF superfamily (TNFSF) member 14 (LIGHT/TNFSF14) could be involved in the pathogenesis of type 2 diabetes mellitus.

Methods: Plasma levels of LIGHT were measured in two cohorts of type 2 diabetes mellitus patients (191 Italian and 40 Norwegian). Human pancreatic islet cells and arterial endothelial cells were used to explore regulation and relevant effects of LIGHT in vitro.

Results: Our major findings were: (1) in both diabetic cohorts, plasma levels of LIGHT were significantly raised compared with sex- and age-matched healthy controls (n&thinsp;=&thinsp;32); (2) enhanced release from activated platelets seems to be an important contributor to the raised LIGHT levels in type 2 diabetes mellitus; (3) in human pancreatic islet cells, inflammatory cytokines increased the release of LIGHT and upregulated mRNA and protein levels of the LIGHT receptors lymphotoxin &beta; receptor (LT&beta;R) and TNF receptor superfamily member 14 (HVEM/TNFRSF14); (4) in these cells, LIGHT attenuated the insulin release in response to high glucose at least partly via pro-apoptotic effects; and (5) in human arterial endothelial cells, glucose boosted inflammatory response to LIGHT, accompanied by an upregulation of mRNA levels of HVEM (also known as TNFRSF14) and LT&beta;R (also known as LTBR).

Conclusions/interpretation: Our findings show that patients with type 2 diabetes mellitus are characterised by increased plasma LIGHT levels. Our in vitro findings suggest that LIGHT may contribute to the progression of type 2 diabetes mellitus by attenuating insulin secretion in pancreatic islet cells and by contributing to vascular inflammation.

Electronic supplementary material: The online version of this article (doi:10.1007/s00125-016-4036-y) contains peer-reviewed but unedited supplementary material, which is available to authorised users.

No MeSH data available.


Related in: MedlinePlus