MicroRNAs responsive to Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis LPS modulate expression of genes regulating innate immunity in human macrophages.
MicroRNAs (miRNAs) are a class of small, noncoding RNAs that regulate post-transcriptional expression of their respective target genes and are responsive to various stimuli, including LPS. Here we examined the early (4 h) miRNA responses of THP1-differentiated macrophages challenged with LPS derived from the periodontal pathogens, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis or environmentally-modified LPS obtained from P. gingivalis grown in cigarette smoke extract. Predicted miRNA-gene target interactions for LPS-responsive miR-29b and let-7f were confirmed using dual-luciferase assays and by transfection experiments using miRNA mimics and inhibitors. Convergent and divergent miRNA profiles were observed in treated samples where differences in miRNA levels related to the type, concentration and incubation times of LPS challenge. Dual-luciferase experiments revealed miR-29b targeting of interleukin-6 receptorα (IL-6Rα) and IFN-γ inducible protein 30 and let-7f targeting of suppressor of cytokine signaling 4 and thrombospondin-1. Transfection experiments confirmed miR-29b and let-7f modulation of IL-6Rα and SOCS4 protein expression levels, respectively. Thus, we have demonstrated convergent/divergent miRNA responses to wild type LPS and its environmentally-modified LPS, and demonstrate miRNA targeting of key genes linked to inflammation and immunity. Our data indicate that these LPS-responsive miRNAs may play a key role in fine-tuning the host response to periodontal pathogens.
Department of Periodontology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA Currently at Department of Periodontics, University of Illinois at Chicago, Chicago, IL, USA.
Afsar R
AR
Naqvi
Department of Periodontology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA Currently at Department of Periodontics, University of Illinois at Chicago, Chicago, IL, USA.
Jezrom B
JB
Fordham
Department of Endodontics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
Asma
A
Khan
Department of Periodontology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA Currently at Department of Periodontics, University of Illinois at Chicago, Chicago, IL, USA snares@uic.edu.
Salvador
S
Nares
D016976:Aggregatibacter actinomycetemcomitans / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects*; D006801:Humans; D007113:Immunity, Innate / Q000187:drug effects* / Q000235:genetics*; D015850:Interleukin-6 / Q000096:biosynthesis / Q000235:genetics; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008264:Macrophages / Q000187:drug effects / Q000276:immunology*; D035683:MicroRNAs / Q000096:biosynthesis* / Q000235:genetics; D016966:Porphyromonas gingivalis / Q000235:genetics / Q000378:metabolism*; D012329:RNA, Bacterial / Q000096:biosynthesis* / Q000235:genetics; D050826:Suppressor of Cytokine Signaling Proteins / Q000096:biosynthesis / Q000235:genetics
C508600:IL6 protein, human; D015850:Interleukin-6; D008070:Lipopolysaccharides; D035683:MicroRNAs; D012329:RNA, Bacterial; C473084:SOCS4 protein, human; D050826:Suppressor of Cytokine Signaling Proteins
Aggregatibacter actinomycetemcomitans LPS; Porphyromonas gingivalis LPS; inflammatory response; macrophage; microRNA