Limits...
MicroRNAs modulate the noncanonical transcription factor NF-kappaB pathway by regulating expression of the kinase IKKalpha during macrophage differentiation.

Li T, Morgan MJ, Choksi S, Zhang Y, Kim YS, Liu ZG - Nat. Immunol. (2010)

Bottom Line: Here we show that during human monocyte-macrophage differentiation, expression of the microRNAs miR-223, miR-15a and miR-16 decreased considerably, which led to higher expression of the serine-threonine kinase IKKalpha in macrophages.However, proinflammatory stimuli in macrophages resulted in greater induction of noncanonical NF-kappaB target genes.Thus, a decrease in certain microRNAs probably prevents macrophage hyperactivation yet primes the macrophage for certain responses to proinflammatory stimuli.

View Article: PubMed Central - PubMed

Affiliation: Cell and Cancer Biology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.

ABSTRACT
MicroRNAs are key regulators of many biological processes, including cell differentiation. Here we show that during human monocyte-macrophage differentiation, expression of the microRNAs miR-223, miR-15a and miR-16 decreased considerably, which led to higher expression of the serine-threonine kinase IKKalpha in macrophages. In macrophages, higher IKKalpha expression in conjunction with stabilization of the kinase NIK induced larger amounts of p52. Because of low expression of the transcription factor RelB in untreated macrophages, high p52 expression repressed basal transcription of both canonical and noncanonical NF-kappaB target genes. However, proinflammatory stimuli in macrophages resulted in greater induction of noncanonical NF-kappaB target genes. Thus, a decrease in certain microRNAs probably prevents macrophage hyperactivation yet primes the macrophage for certain responses to proinflammatory stimuli.

Show MeSH
MicroRNAs target the IKKα mRNA(a) Distribution of predicted target sites for five relevant microRNAs in 3″ UTR of IKKα. (b, c) Real time PCR analysis of different microRNAs in monocytes (Mo) vs. macrophages (MΦ) as indicated. Error bars, +/− standard deviation from the mean. Data representative of at least 5 independent experiments (d) Monocytes lysates (Mo) from cells transfected with miRNA inhibitors containing control oligo, pooled inhibitors for microRNAs 15a, 16 and 223 or the combinations thereof as indicated (48 hours after transfection) immunoblotted with IKKα and IKKβ antibodies. (e) Cell extracts from macrophages (MΦ) transfected with microRNAs mimic control oligo or pooled mimics immunoblotted with anti-IKKα and anti-IKKβ antibodies. TRADD and β-actin blots indicate loading of lanes (d, e)
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC2926307&req=5

Figure 2: MicroRNAs target the IKKα mRNA(a) Distribution of predicted target sites for five relevant microRNAs in 3″ UTR of IKKα. (b, c) Real time PCR analysis of different microRNAs in monocytes (Mo) vs. macrophages (MΦ) as indicated. Error bars, +/− standard deviation from the mean. Data representative of at least 5 independent experiments (d) Monocytes lysates (Mo) from cells transfected with miRNA inhibitors containing control oligo, pooled inhibitors for microRNAs 15a, 16 and 223 or the combinations thereof as indicated (48 hours after transfection) immunoblotted with IKKα and IKKβ antibodies. (e) Cell extracts from macrophages (MΦ) transfected with microRNAs mimic control oligo or pooled mimics immunoblotted with anti-IKKα and anti-IKKβ antibodies. TRADD and β-actin blots indicate loading of lanes (d, e)

Mentions: MicroRNAs not only target mRNA for degradation, but can also inhibit mRNA translation11,13. Using the Memorial Sloan-Kettering Cancer Center miRNA database19 (http://www.microrna.org/) we searched for microRNAs present in human monocytes that have a predicted target sequence in the 3′ UTR of IKKα. We identified possible target sites for let-7, miR-223, miR-16, miRNA-142-5p, and two target sites for miR15a, one of which overlaps with the putative miR-16 site (Fig. 2a). miR-223 and miR-15a-miR16 target sites were only about 35 nucleotides (n.t.) apart, a condition that may result in cooperativity between target sites, especially of the same miRNA20. With the exception of the putative let-7 target site, which occurred centrally, all miRNA target sites were at the 5′ and 3′ ends of the IKKα 3′ UTR. A recent report suggests that miRNA target sites at either end of the UTR are more likely to be functional targets than those in the middle21.


MicroRNAs modulate the noncanonical transcription factor NF-kappaB pathway by regulating expression of the kinase IKKalpha during macrophage differentiation.

Li T, Morgan MJ, Choksi S, Zhang Y, Kim YS, Liu ZG - Nat. Immunol. (2010)

MicroRNAs target the IKKα mRNA(a) Distribution of predicted target sites for five relevant microRNAs in 3″ UTR of IKKα. (b, c) Real time PCR analysis of different microRNAs in monocytes (Mo) vs. macrophages (MΦ) as indicated. Error bars, +/− standard deviation from the mean. Data representative of at least 5 independent experiments (d) Monocytes lysates (Mo) from cells transfected with miRNA inhibitors containing control oligo, pooled inhibitors for microRNAs 15a, 16 and 223 or the combinations thereof as indicated (48 hours after transfection) immunoblotted with IKKα and IKKβ antibodies. (e) Cell extracts from macrophages (MΦ) transfected with microRNAs mimic control oligo or pooled mimics immunoblotted with anti-IKKα and anti-IKKβ antibodies. TRADD and β-actin blots indicate loading of lanes (d, e)
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2926307&req=5

Figure 2: MicroRNAs target the IKKα mRNA(a) Distribution of predicted target sites for five relevant microRNAs in 3″ UTR of IKKα. (b, c) Real time PCR analysis of different microRNAs in monocytes (Mo) vs. macrophages (MΦ) as indicated. Error bars, +/− standard deviation from the mean. Data representative of at least 5 independent experiments (d) Monocytes lysates (Mo) from cells transfected with miRNA inhibitors containing control oligo, pooled inhibitors for microRNAs 15a, 16 and 223 or the combinations thereof as indicated (48 hours after transfection) immunoblotted with IKKα and IKKβ antibodies. (e) Cell extracts from macrophages (MΦ) transfected with microRNAs mimic control oligo or pooled mimics immunoblotted with anti-IKKα and anti-IKKβ antibodies. TRADD and β-actin blots indicate loading of lanes (d, e)
Mentions: MicroRNAs not only target mRNA for degradation, but can also inhibit mRNA translation11,13. Using the Memorial Sloan-Kettering Cancer Center miRNA database19 (http://www.microrna.org/) we searched for microRNAs present in human monocytes that have a predicted target sequence in the 3′ UTR of IKKα. We identified possible target sites for let-7, miR-223, miR-16, miRNA-142-5p, and two target sites for miR15a, one of which overlaps with the putative miR-16 site (Fig. 2a). miR-223 and miR-15a-miR16 target sites were only about 35 nucleotides (n.t.) apart, a condition that may result in cooperativity between target sites, especially of the same miRNA20. With the exception of the putative let-7 target site, which occurred centrally, all miRNA target sites were at the 5′ and 3′ ends of the IKKα 3′ UTR. A recent report suggests that miRNA target sites at either end of the UTR are more likely to be functional targets than those in the middle21.

Bottom Line: Here we show that during human monocyte-macrophage differentiation, expression of the microRNAs miR-223, miR-15a and miR-16 decreased considerably, which led to higher expression of the serine-threonine kinase IKKalpha in macrophages.However, proinflammatory stimuli in macrophages resulted in greater induction of noncanonical NF-kappaB target genes.Thus, a decrease in certain microRNAs probably prevents macrophage hyperactivation yet primes the macrophage for certain responses to proinflammatory stimuli.

View Article: PubMed Central - PubMed

Affiliation: Cell and Cancer Biology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.

ABSTRACT
MicroRNAs are key regulators of many biological processes, including cell differentiation. Here we show that during human monocyte-macrophage differentiation, expression of the microRNAs miR-223, miR-15a and miR-16 decreased considerably, which led to higher expression of the serine-threonine kinase IKKalpha in macrophages. In macrophages, higher IKKalpha expression in conjunction with stabilization of the kinase NIK induced larger amounts of p52. Because of low expression of the transcription factor RelB in untreated macrophages, high p52 expression repressed basal transcription of both canonical and noncanonical NF-kappaB target genes. However, proinflammatory stimuli in macrophages resulted in greater induction of noncanonical NF-kappaB target genes. Thus, a decrease in certain microRNAs probably prevents macrophage hyperactivation yet primes the macrophage for certain responses to proinflammatory stimuli.

Show MeSH