Multi-Step Regulation of the TLR4 Pathway by the miR-125a~99b~let-7e Cluster

Curtale, Graziella; Renzi, Tiziana Ada; Mirolo, Massimiliano; Drufuca, Lorenzo; Albanese, Manuel; Luca, Mariacristina De; Rossato, Marzia; Bazzoni, Flavia; Locati, Massimo

doi:10.3389/fimmu.2018.02037

Cited by 34 publications

(42 citation statements)

References 36 publications

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“…Here, we identified a recurrent mutation in the 3’UTR of TLR4 , which might affect the post‐transcriptional modulation of TLR4 via miRNA. TLR4 regulation by miRNAs has been described in different cell types (Curtale et al, ; Wang et al, ; Yan et al, ), including melanoma (Jin et al, ). Another novel recurrent mutation identified in this study is in MAP2K1, which encodes MEK1.…”

Section: Discussionmentioning

confidence: 99%

Functional analysis of RPS27 mutations and expression in melanoma

Floristán

Morales

Hanniford

et al. 2019

Pigment Cell Melanoma Res

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Next‐generation sequencing has enabled genetic and genomic characterization of melanoma to an unprecedent depth. However, the high mutational background plus the limited depth of coverage of whole‐genome sequencing performed on cutaneous melanoma samples make the identification of novel driver mutations difficult. We sought to explore the somatic mutation portfolio in exonic and gene regulatory regions in human melanoma samples, for which we performed targeted sequencing of tumors and matched germline DNA samples from 89 melanoma patients, identifying known and novel recurrent mutations. Two recurrent mutations found in the RPS27 promoter associated with decreased RPS27 mRNA levels in vitro. Data mining and IHC analyses revealed a bimodal pattern of RPS27 expression in melanoma, with RPS27‐low patients displaying worse prognosis. In vitro characterization of RPS27‐high and RPS27‐low melanoma cell lines, as well as loss‐of‐function experiments, demonstrated that high RPS27 status provides increased proliferative and invasive capacities, while low RPS27 confers survival advantage in low attachment and resistance to therapy. Additionally, we demonstrate that 10 other cancer types harbor bimodal RPS27 expression, and in those, similarly to melanoma, RPS27‐low expression associates with worse clinical outcomes. RPS27 promoter mutation could thus represent a mechanism of gene expression modulation in melanoma patients, which may have prognostic and predictive implications.

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Section: Discussionmentioning

confidence: 99%

Functional analysis of RPS27 mutations and expression in melanoma

Floristán

Morales

Hanniford

et al. 2019

Pigment Cell Melanoma Res

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“…Up-Regulation of miRNAs in Differentiating MM6 Cells. Stimulation of TLRs in monocytic cells leads to up-regulation of certain miRNAs (4,21). This was confirmed also for MM6 cells differentiated in presence of LPS (TLR4) or zymosan (TLR2) for 96 h. qPCR analysis was performed for seven miRNAs, selected from Affymetrix screening.…”

Section: Mass Spectrometric Analysis Of Dicer Immunoprecipitates Valimentioning

confidence: 68%

“…Furthermore, it was recently published that miR-125a-5p and let-7e down-regulate TNFα (and other cytokines) in THP-1 cells (21), and we found here that PGE 2 up-regulated the cluster miR-99b-5p/let-7e-5p/miR-125a-5p. This cluster was suggested to be part of the late-induced IL-10 effects functioning as negative regulator of the LPS response (21). Bacterial components such as LPS induce formation of PGE 2 in monocytic cells (53); thus, it appears reasonable that this, in turn, could induce formation of miR-99a and miR-125a, contributing to negative feedback control of TNFα formation.…”

Section: Discussionmentioning

confidence: 99%

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Dicer up-regulation by inhibition of specific proteolysis in differentiating monocytic cells

Basavarajappa

Uebbing

Kreiß

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

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Dicer is a ribonuclease III enzyme in biosynthesis of micro-RNAs (miRNAs). Here we describe a regulation of Dicer expression in monocytic cells, based on proteolysis. In undifferentiated Mono Mac 6 (MM6) cells, full-length Dicer was undetectable; only an ∼50-kDa fragment appeared in Western blots. However, when MM6 cells were treated with zymosan or LPS during differentiation with TGF-β and 1,25diOHvitD3, full-length Dicer became abundant together with varying amounts of ∼170and ∼50-kDa Dicer fragments. Mass spectrometry identified the Dicer fragments and showed cleavage about 450 residues upstream from the C terminus. Also, PGE 2 (prostaglandin E2) added to differentiating MM6 cells up-regulated full-length Dicer, through EP2/EP4 and cAMP. The TLR stimuli strongly induced miR-146a-5p, while PGE 2 increased miR-99a-5p and miR-125a-5p, both implicated in down-regulation of TNFα. The Ser protease inhibitor AEBSF (4-[2-aminoethyl] benzene sulfonyl fluoride) up-regulated full-length Dicer, both in MM6 cells and in primary human blood monocytes, indicating a specific proteolytic degradation. However, AEBSF alone did not lead to a general increase in miR expression, indicating that additional mechanisms are required to increase miRNA biosynthesis. Finally, differentiation of monocytes to macrophages with M-CSF or GM-CSF strongly up-regulated full-length Dicer. Our results suggest that differentiation regimens, both in the MM6 cell line and of peripheral blood monocytes, inhibit an apparently constitutive Dicer proteolysis, allowing for increased formation of miRNAs. miRNA | PGE 2 | macrophage D icer is an RNA endonuclease type III/RNase III enzyme best known for its canonical function in biosynthesis of micro-RNAs (miRNA), which are predicted to control up to 60% of protein-coding genes by targeting specific mRNA for degradation or translation repression. MiRNA are formed from primary transcripts (pri-miRNA) in two stages of processing. Pri-miRNAs, transcribed by RNA polymerase II, are first cleaved by the nuclear microprocessor complex (Drosha and its partner DGCR8) (1). The resulting hairpin structures called pre-miRNAs (precursor-miRNAs) consist of ∼70 nucleotides with two nucleotides overhanging at the 3′ end. Following exportin-5-mediated transport to the cytosol, final processing by Dicer yields ∼22 nucleotide mature double-stranded miRNAs. Only one of the strands (the guide strand) of miRNA is then incorporated to RNA-induced silencing complex (RISC) and directs this complex to 3′ untranslated regions (UTR) of target mRNAs for inhibition of translation (1, 2). Biogenesis of miRNAs occurs under stringent spatial and temporal control, and dysregulation can be associated with human diseases (3). Several recent findings show that miRNAs formed in inflammatory cells play major roles in regulating inflammatory responses (4).Dicer is a large enzyme (∼220 kDa) with several domains including an N-terminal helicase domain, DUF283 (domain of unknown function), PAZ (Piwi-Argonaute-Zwille) domain, two RNase III domains (RNas...

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“…Notably, although the majority of target genes was not shared by different miRNAs of the subset, we found some important genes with implication in the inflammatory response simultaneously targeted by miR-125a-5p and let-7e-5p or miR-574-3p. Importantly, the miR-99b/let-7e/miR-125a cluster has been shown to have antiinflammatory function in immune cells (46). Further, miR-125a promotes the fundamental shift from inflammation to immune suppression by controlling regulatory T cells homeostasis (43).…”

Section: Discussionmentioning

confidence: 99%

An Anti-inflammatory microRNA Signature Distinguishes Group 3 Innate Lymphoid Cells From Natural Killer Cells in Human Decidua

et al. 2020

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Innate lymphoid cells (ILCs) are a heterogeneous subset of lymphocytes deeply implicated in the innate immune responses to different pathogens, in lymphoid organogenesis and in the maintenance of tissue homeostasis. Group 3 innate lymphoid cells (ILC3) have been detected in human decidua, where they play a role in the early inflammatory phase favoring implantation and tissue remodeling as well as in the subsequent regulatory phase preventing fetal rejection and supporting neoangiogenesis. A balance between inflammation and immune tolerance is required to maintain pregnancy, thus maternal immune system must be controlled by finely tuned mechanisms. microRNAs (miRNAs) are small non-coding RNAs with important regulatory roles in immune cells, but their function in decidual ILC3 (dILC3) and in decidual NK (dNK) cells is still undefined. Here, we examined the miRNome by microarray in these cells during the first trimester of pregnancy and compared with miRNA profiles of peripheral blood NK (pbNK) cells from pregnant women. We show that distinct miRNA profiles could clearly distinguish dILC3 from NK cells. Correlation analyses revealed that dNK and pbNK miRNome profiles are more similar to each other as compared to dILC3. In particular, we identified 302 and 279 mature miRNAs differentially expressed in dILC3 as compared to dNK and pbNK, respectively. The expression of miR-574-3p and the miR-99b/let-7e/miR-125a miRNA cluster resulted the most increased in dILC3. Remarkably, gene ontology analysis and pathway enrichments of miRNA targets revealed an involvement of these miRNAs in the promotion of anti-inflammatory responses. In agreement to this finding, we also found a higher expression of the anti-inflammatory miR-146a-5p in dILC3 with respect to NK cells. Overall, our data identified specific miRNA signatures distinguishing dILC3, dNK, and pbNK cells. Our data suggest the existence of a tight epigenetic control mediated by miRNAs in dILC3, potentially acting as a brake to prevent exaggerated inflammatory responses and to maintain the immune homeostasis in the early phases of pregnancy.

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Multi-Step Regulation of the TLR4 Pathway by the miR-125a~99b~let-7e Cluster

Cited by 34 publications

References 36 publications

Functional analysis of RPS27 mutations and expression in melanoma

Functional analysis of RPS27 mutations and expression in melanoma

Dicer up-regulation by inhibition of specific proteolysis in differentiating monocytic cells

An Anti-inflammatory microRNA Signature Distinguishes Group 3 Innate Lymphoid Cells From Natural Killer Cells in Human Decidua

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