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Article: Lipopolysaccharide and hypoxia-induced HIF-1 activation in human gingival fibroblasts

TitleLipopolysaccharide and hypoxia-induced HIF-1 activation in human gingival fibroblasts
Authors
KeywordsCell hypoxia
Chronic periodontitis
Hypoxia-inducible factor 1α subunit
Lipopolysaccharides
Toll-like receptor 4
Vascular endothelial growth factor A
Issue Date2012
PublisherAmerican Academy of Periodontology. The Journal's web site is located at http://www.perio.org
Citation
Journal Of Periodontology, 2012, v. 83 n. 6, p. 816-824 How to Cite?
AbstractBackground: We previously reported that chronic periodontal inflammation causes the accumulation of the transcriptional activator hypoxia-inducible factor-1α (HIF-1 α) in human gingival fibroblasts (HGFs) in vivo. Here, evidence is provided that bacterial lipopolysaccharides (LPS) and cellular hypoxia, both associated with periodontitis, can individually, or in combination, lead to the accumulation and activation of HIF-1 in HGF in vitro. Methods: Primary gingival fibroblasts were cultured from human gingival biopsies. HIF-1 α peptide from HGFs treated with Escherichia coli LPS under normoxia or hypoxia was detected by nuclear protein extraction, immunoprecipitation, immunoblotting, and immunocytofluorescence. HIF-1 α transcripts were detected using reverse transcription polymerase chain reaction (PCR). The transcript expression levels of vascular endothelial growth factor-A (VEGF-A), a downstream gene of HIF-1α, were assessed by quantitative real-time PCR. Results: Two HIF-1 α splicing transcription variants were found to be constitutively expressed in HGFs. E. coli LPS induced a dose- and time-dependent nuclear accumulation of HIF-1 α peptide in HGFs. This accumulation could be attenuated by treatment with a Toll-like receptor 4 (TLR4)-neutraliz-ing antibody. Under hypoxia, LPS further increased HIF-1α accumulation in HGFs. VEGF-A transcript expression was upregulated by LPS under both normoxia and hypoxia but was downregulated by pretreatment with TLR4-neutralizing antibody or the specific HIF-1α inhibitor 3-(5'-hydroxymeth-yl-2'-furyl)-1-benzyl indazole. Conclusion: LPS induces the nuclear accumulation of HIF-1 α in HGFs and induces HIF-1 biologic activity under normoxia or hypoxia possibly through TLR4.
Persistent Identifierhttp://hdl.handle.net/10722/154732
ISSN
2014 Impact Factor: 2.706
2013 SCImago Journal Rankings: 1.143
ISI Accession Number ID
Funding AgencyGrant Number
University of Hong Kong200807176129
201007176307
200911159126
Funding Information:

This project was supported by the University of Hong Kong Small Project Funding Grants 200807176129 and 201007176307 and Seed Funding Grant 200911159126. The authors report no conflicts of interest related to this study.

References

 

DC FieldValueLanguage
dc.contributor.authorLi, JPen_HK
dc.contributor.authorLi, FYLen_HK
dc.contributor.authorXu, Aen_HK
dc.contributor.authorCheng, Ben_HK
dc.contributor.authorTsao, SWen_HK
dc.contributor.authorFung, MLen_HK
dc.contributor.authorLeung, WKen_HK
dc.date.accessioned2012-08-08T08:27:10Z-
dc.date.available2012-08-08T08:27:10Z-
dc.date.issued2012en_HK
dc.identifier.citationJournal Of Periodontology, 2012, v. 83 n. 6, p. 816-824en_HK
dc.identifier.issn0022-3492en_HK
dc.identifier.urihttp://hdl.handle.net/10722/154732-
dc.description.abstractBackground: We previously reported that chronic periodontal inflammation causes the accumulation of the transcriptional activator hypoxia-inducible factor-1α (HIF-1 α) in human gingival fibroblasts (HGFs) in vivo. Here, evidence is provided that bacterial lipopolysaccharides (LPS) and cellular hypoxia, both associated with periodontitis, can individually, or in combination, lead to the accumulation and activation of HIF-1 in HGF in vitro. Methods: Primary gingival fibroblasts were cultured from human gingival biopsies. HIF-1 α peptide from HGFs treated with Escherichia coli LPS under normoxia or hypoxia was detected by nuclear protein extraction, immunoprecipitation, immunoblotting, and immunocytofluorescence. HIF-1 α transcripts were detected using reverse transcription polymerase chain reaction (PCR). The transcript expression levels of vascular endothelial growth factor-A (VEGF-A), a downstream gene of HIF-1α, were assessed by quantitative real-time PCR. Results: Two HIF-1 α splicing transcription variants were found to be constitutively expressed in HGFs. E. coli LPS induced a dose- and time-dependent nuclear accumulation of HIF-1 α peptide in HGFs. This accumulation could be attenuated by treatment with a Toll-like receptor 4 (TLR4)-neutraliz-ing antibody. Under hypoxia, LPS further increased HIF-1α accumulation in HGFs. VEGF-A transcript expression was upregulated by LPS under both normoxia and hypoxia but was downregulated by pretreatment with TLR4-neutralizing antibody or the specific HIF-1α inhibitor 3-(5'-hydroxymeth-yl-2'-furyl)-1-benzyl indazole. Conclusion: LPS induces the nuclear accumulation of HIF-1 α in HGFs and induces HIF-1 biologic activity under normoxia or hypoxia possibly through TLR4.en_HK
dc.languageengen_US
dc.publisherAmerican Academy of Periodontology. The Journal's web site is located at http://www.perio.orgen_HK
dc.relation.ispartofJournal of Periodontologyen_HK
dc.subjectCell hypoxiaen_HK
dc.subjectChronic periodontitisen_HK
dc.subjectHypoxia-inducible factor 1α subuniten_HK
dc.subjectLipopolysaccharidesen_HK
dc.subjectToll-like receptor 4en_HK
dc.subjectVascular endothelial growth factor Aen_HK
dc.titleLipopolysaccharide and hypoxia-induced HIF-1 activation in human gingival fibroblastsen_HK
dc.typeArticleen_HK
dc.identifier.emailTsao, SW: gswtsao@hkucc.hku.hken_HK
dc.identifier.emailFung, ML: fungml@hkucc.hku.hken_HK
dc.identifier.emailLeung, WK: ewkleung@hkucc.hku.hken_HK
dc.identifier.emailLi, FYL: francois.li@hku.hk-
dc.identifier.emailXu, A: amxu@hkucc.hku.hk-
dc.identifier.authorityTsao, SW=rp00399en_HK
dc.identifier.authorityFung, ML=rp00433en_HK
dc.identifier.authorityLeung, WK=rp00019en_HK
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.doi10.1902/jop.2011.110458en_HK
dc.identifier.pmid22087807-
dc.identifier.scopuseid_2-s2.0-84861792062en_HK
dc.identifier.hkuros198908-
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-84861792062&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume83en_HK
dc.identifier.issue6en_HK
dc.identifier.spage816en_HK
dc.identifier.epage824en_HK
dc.identifier.isiWOS:000305492800017-
dc.publisher.placeUnited Statesen_HK
dc.identifier.scopusauthoridLi, JP=40561311800en_HK
dc.identifier.scopusauthoridLi, FYL=55240528800en_HK
dc.identifier.scopusauthoridXu, A=55239908900en_HK
dc.identifier.scopusauthoridCheng, B=35329066400en_HK
dc.identifier.scopusauthoridTsao, SW=7102813116en_HK
dc.identifier.scopusauthoridFung, ML=7101955092en_HK
dc.identifier.scopusauthoridLeung, WK=25224691800en_HK

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