Dataset Information

Hypoxia inhibits TNF-α-induced TSLP expression in keratinocytes.

ABSTRACT: The expression of thymic stromal lymphopoietin (TSLP), a cytokine which greatly contributes to the induction of type I allergy, is upregulated in chronic inflammation such as atopic dermatitis and psoriasis. As hypoxia in the epidermis is important for maintaining skin homeostasis, we examined the regulation of TSLP expression by hypoxic conditions in normal skin epithelial tissues. TNF-α-induced expression of TSLP in human keratinocyte HaCaT and in mouse keratinocyte PAM212 cell lines were inhibited under hypoxic condition (1% O2), although the mRNA expressions of TNF-α, IL-6, IL-8, MCP-1, and VEGF-A were not inhibited. Hypoxia-mimicking conditions, which include NiCl2, CoCl2, and DMOG, an inhibitor of 2-oxoglutarate-dependent enzymes, also selectively inhibited TNF-α-induced TSLP expression. These results suggested that inactivation of prolyl hydroxylase by hypoxia and hypoxia-mimicking conditions is involved in the repression of TNF-α-induced TSLP expression. Interestingly, the inhibition of TSLP production by hypoxic treatment was significantly reversed by treatment with the HIF-2α antagonist but not with the HIF-1α inhibitor. DMOG-induced inhibition of TSLP promoter activity was dependent on the -71 to +185 bp promoter region, suggesting that the binding of HIF-2 to hypoxia response element (HRE) in this region repressed the TSLP expression. These results indicated that hypoxia and hypoxia-mimicking conditions inhibited TSLP expression via HIF-2 and HRE-dependent mechanisms. Therefore, PHD and HIF-2α could be a new strategy for treatment of atopic dermatitis and psoriasis.

SUBMITTER: Tashiro N

PROVIDER: S-EPMC6827910 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:1. Endothelin-1 (ET-1) and tumor necrosis factor alpha (TNFalpha) by their action on adipocytes have been independently linked to the pathogenesis of insulino-resistance. In isolated adipocytes, TNFalpha induces the expression of the inducible nitric oxide synthase (iNOS). The purpose of the present work was, in the 3T3-F442A adipocyte cell line, to characterise TNFalpha-induced iNOS expression and to determine whether or not ET-1 could influence TNFalpha-induced iNOS expression and NO production. 2. In differentiated 3T3-F442A, treatment with TNFalpha (20 ng ml(-1)) induced the expression of a functional iNOS as demonstrated by nitrite assay, Western blot, reverse transcription-polymerase chain reaction and Northern blot analysis. TNFalpha-induced iNOS expression requires nuclear factor kappaB activation, but does not necessitate the activation of the PI-3 kinase/Akt and P38-MAP kinase pathways. 3. ET-1, but not ET-3, inhibited the TNFalpha-induced expression of iNOS protein and mRNA as well as nitrite production. The effects of ET-1 were blocked by a specific ETA (BQ123, pA(2) 7.4) but not by a specific ETB receptor antagonist (BQ788). 3T3-F442A adipocytes express the mRNAs for prepro-ET-1 and the ET-A receptor subtype, but not for the ET-B subtype. 4. The inhibitory effect of ET-1 was not affected by bisindolylmaleimide, SB 203580 or indomethacin, inhibitors of protein kinase C, p38-MAP kinase and cyclooxygenase, respectively, and was not associated with cAMP production. However, the effect of ET-1 was partially reversed by wortmannin, suggesting the involvement of PI3 kinase in the transduction signal of ET-1. 5. Differentiated 3T3-F442A adipocytes did not release ET-1 with or without exposure to TNFalpha, although the mRNA for preproET-1 was detected in both pre- and differentiated adipocytes. 6. Thus, these results confirm that adipocytes are a target for circulating ET-1 and demonstrate that the activation of the ETA receptor subtype can prevent TNFalpha-induced iNOS expression.

Dataset Information

Hypoxia inhibits TNF-α-induced TSLP expression in keratinocytes.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets