Cited by 29Neuroinflammation and Neurodegeneration MechanismsMicroRNA in disease regulationIntracerebral and Subarachnoid Hemorrhage Research

MicroRNA miR-27b-3p regulate microglial inflammation response and cell apoptosis by inhibiting A20 (TNF-α-induced protein 3)

Open access
Li, Liping, Qi, Chao, Liu, Yuanyuan, Shen, Youliang, Zhao, Xia, Qin, Han, Zhang, Yi, Yu, Tengbo·2021·Bioengineered

Abstract

Inflammatory reaction exerts a pivotal role in secondary damage after cerebral hemorrhage and spinal cord injury. miRNAs can both promote and inhibit inflammatory actions among microglial cells. The objective of the present paper was to figure out whether miR-27b-3p produced regulatory effects during processes of microglial inflammation. Lipopolysaccharides (LPS) were used to prepare microglial activation models. Following miR-27b-3p overexpression and interference, the RNA and protein levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1β were subjected to real-time fluorescent quantitative PCR (qPCR) and western blot assays, respectively. Cellular apoptosis was subjected to flow cytometry and miR-27b-3p target genes were visualized using a dual luciferase reporter system for verification. The levels of TNF-α, IL-6, and IL-1β mRNA in miR-27b-3p-overexpressed microglial cells were markedly increased compared to the control. Apoptosis of microglial cells was increased markedly in the overexpressed miR-27b-3p group compared to the negative control. Conversely, a different result was presented in the microglial transfected with miR-27b-3p inhibitors. The downregulation of A20, a miR-27b-3p target gene, mediated levels of TNF-α, IL-6, and IL-1β. Furthermore, A20 reduced microglial apoptosis. These data revealed that miR-27b-3p could mediate not only microglia activation but also neuroinflammation via downregulating A20 expression. Thus, miR-27b-3p is regarded as gene therapy in treating cerebral hemorrhage and spinal cord injury.

AI snapshot

Written from the paper’s full text.

TL;DR

In LPS-activated mouse primary microglia, miR-27b-3p promoted inflammatory cytokine expression and apoptosis, while A20 (TNFAIP3) suppressed these effects. Dual-luciferase and expression assays identified A20 as a direct target of miR-27b-3p, suggesting miR-27b-3p aggravates neuroinflammation by downregulating A20.

Key findings

  • LPS treatment increased Iba1 and inflammatory cytokines: TNF-α, IL-6, and IL-1β were higher in LPS-treated microglia than controls (P < 0.01).
  • miR-27b-3p overexpression increased TNF-α, IL-6, and IL-1β mRNA/protein and apoptosis; apoptosis was 37.44% in miR-27b-3p mimics, 19.59% in mimic-NC, 10.22% in miR-27b inhibitor, and 19.97% in inhibitor NC.
  • A20 was validated as a miR-27b-3p target: luciferase activity fell with wild-type A20 3’UTR plus miR-27b-3p but not with mutant A20, and miR-27b-3p overexpression reduced A20 by qPCR, western blot, and immunofluorescence.
  • A20 overexpression decreased TNF-α, IL-6, and IL-1β and reduced apoptosis; apoptosis was 10.79% in A20-overexpressed, 19.56% in NC, 35.69% in si-A20, and 17.61% in si-NC cells.

Methods

  • Primary microglia were isolated from whole brain cortex of 30 newborn (2–4 d) specified pathogen-free male C57BL/6 mice, cultured, and activated with 100 ng/mL LPS for 24 h.
  • Cells were transfected with miR-27b-3p mimics/inhibitor, LV-A20 overexpression, LV-siRNA-A20, or negative controls; readouts included qPCR, western blot, ELISA, immunofluorescence, flow cytometry, and dual-luciferase reporter assays in 293T cells.
  • Data came from at least three independent experiments, presented as means ± SD, analyzed with two-tailed Student’s t-tests or one-way ANOVA with Dunnett’s tests; significance was set at p < 0.05.

Limitations

  • The paper does not state limitations explicitly.
  • Evident from the text: all experiments are in vitro (mouse primary microglia and 293T cells), with no in vivo cerebral hemorrhage or spinal cord injury model, so the therapeutic gene-therapy claim is not directly tested.
  • Evident from the text: there are reporting inconsistencies, including Figure 5a’s legend referring to “miR-129-5p” rather than miR-27b-3p, and the dual-luciferase methods mentioning both psiCHECK-2 and pmirGLO vectors.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1080/21655979.2021.1969195

Cites

41 of 41 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 2 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    LPS treatment (100 ng/mL) increased TNF-α levels in microglia compared with control (P < 0.01).

    “ELISA assays indicated that TNF-α, IL-6, and IL-1β levels were higher in LSP-treated microglia than in the control with P < 0.01 (Figure 2b-2d).”
    Quote in the paperSubstantial claim
  • Findingown data

    LPS treatment (100 ng/mL) increased IL-6 levels in microglia compared with control (P < 0.01).

    “ELISA assays indicated that TNF-α, IL-6, and IL-1β levels were higher in LSP-treated microglia than in the control with P < 0.01 (Figure 2b-2d).”
    Quote in the paperSubstantial claim
  • Findingown data

    Overexpressed miR-27b-3p reduced A20 expression in microglial cells, as shown by qPCR, Western blot, and immunofluorescence.

    “Besides, overexpressed miR-27b-3p remarkably reduced A20 expression and that was deeply verified in the results of qPCR, Western blot, and immunofluorescence (Figure 5b-d).”
    Quote in the paperSubstantial claim
  • Findingown data

    LPS treatment (100 ng/mL) increased IL-1β levels in microglia compared with control (P < 0.01).

    “ELISA assays indicated that TNF-α, IL-6, and IL-1β levels were higher in LSP-treated microglia than in the control with P < 0.01 (Figure 2b-2d).”
    Quote in the paperSubstantial claim
  • Interpretationown data

    miR-27b-3p mediates microglia activation and neuroinflammation via downregulating A20 expression.

    “These data revealed that miR-27b-3p could mediate not only microglia activation but also neuroinflammation via downregulating A20 expression.”
    • Also stated in: § Conclusion · hedged
      “It might increase the expression of inflammatory factors and promote microglial cell apoptosis by regulating A20, thus leading to the aggravation of neuroinflammation in microglial cells.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The effects of miR-27b-3p on microglial inflammation and apoptosis are mediated by downregulation of A20.
  • The quote only partly states this claim. 3
  • May combine two claims. 13
  • The quote only partly states this claim.

    Findingown data

    LPS treatment (100 ng/mL) increased Iba1 expression in primary mouse microglia.

    “Iba1 as an activated microglia marker was highly expressed following LPS stimulation (Figure 2a).”
    • Also stated in: § Discussion · plain
      “Following LPS stimulation of microglia, we observed an increase in the Iba1 expression.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    Co-transfection of miR-27b-3p with wild-type A20 3'UTR reduced luciferase activity, whereas mutant A20 3'UTR showed no change.

    “The results suggested that the fluorescence activity of pmirGLO-A20-3’UTR and miR-27b-3p in the co-transfection group was reduced, whereas there was no change in pmirGLO-A20-3’UTR-mutation (Figure 5a).”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    miR-27b-3p overexpression increased TNF-α mRNA and protein levels in LPS-treated microglia, while miR-27b-3p inhibition decreased them.

    “qPCR and Western blot findings illustrated that the expression of TNF-α was considerably elevated at mRNA and protein levels in the miR-27b-3p mimic whereas dramatically declined in the miR-27b-3p inhibitor (Figure 3b-e).”
    • Also stated in: § Abstract · plain
      “The levels of TNF-α, IL-6, and IL-1β mRNA in miR-27b-3p-overexpressed microglial cells were markedly increased compared to the control.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    A20 overexpression decreased IL-6 mRNA and protein levels in LPS-treated microglia, while A20 silencing increased them.

    “The mRNA and protein levels of TNF-α, IL-6, and IL-1β were markedly increased in the si-A20 whereas greatly decreased in the A20 overexpressed cells (Figure 6c-f).”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    A20 overexpression decreased apoptosis of LPS-treated microglial cells, while A20 silencing increased apoptosis.

    “The effects of A20 on microglial apoptosis were determined via flow cytometry which suggested that apoptosis of A20 overexpressed, the NC, the si-A20, and the si-NC were 10.79%, 19.56%, 35.69%, and 17.61%, respectively (Figure 6g) which revealed that A20 inhibited microglial inflammation and apoptosis.”
    • Also stated in: § Abstract · plain
      “Furthermore, A20 reduced microglial apoptosis.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    A20 overexpression decreased IL-1β mRNA and protein levels in LPS-treated microglia, while A20 silencing increased them.

    “The mRNA and protein levels of TNF-α, IL-6, and IL-1β were markedly increased in the si-A20 whereas greatly decreased in the A20 overexpressed cells (Figure 6c-f).”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    miR-27b-3p overexpression increased apoptosis of LPS-treated microglial cells, while miR-27b-3p inhibition decreased apoptosis.

    “Apoptosis of microglial cells in the miR-27b-3p mimics, the mimic-NC, the miR-27b inhibitor, and the inhibitor NC group were 37.44%, 19.59%, 10.22%, and 19.97%, respectively (Figure 4a).”
    • Also stated in: § Abstract · plain
      “Apoptosis of microglial cells was increased markedly in the overexpressed miR-27b-3p group compared to the negative control.”
    Quote in the paperSubstantial claim
  • May combine two claims. The quote only partly states this claim.

    Findingown data

    miR-27b-3p overexpression increased IL-6 mRNA and protein levels in LPS-treated microglia, while miR-27b-3p inhibition decreased them.

    “miR-27b-3p promoted expressions of TNF-α, IL-6, and IL-1β in microglial cells treated with 100 ng/mL LPS (n = 3).”
    • Also stated in: § Abstract · plain
      “The levels of TNF-α, IL-6, and IL-1β mRNA in miR-27b-3p-overexpressed microglial cells were markedly increased compared to the control.”
    Quote in the paperSubstantial claim
  • May combine two claims. The quote only partly states this claim.

    Findingown data

    miR-27b-3p overexpression increased IL-1β mRNA and protein levels in LPS-treated microglia, while miR-27b-3p inhibition decreased them.

    “miR-27b-3p promoted expressions of TNF-α, IL-6, and IL-1β in microglial cells treated with 100 ng/mL LPS (n = 3).”
    • Also stated in: § Abstract · plain
      “The levels of TNF-α, IL-6, and IL-1β mRNA in miR-27b-3p-overexpressed microglial cells were markedly increased compared to the control.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    A20 overexpression decreased TNF-α mRNA and protein levels in LPS-treated microglia, while A20 silencing increased them.

    “The mRNA and protein levels of TNF-α, IL-6, and IL-1β were markedly increased in the si-A20 whereas greatly decreased in the A20 overexpressed cells (Figure 6c-f).”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    miR-27b-3p overexpression increased Iba1 expression in LPS-treated microglia, while miR-27b-3p inhibition decreased it.

    “Compared with the negative control, immunofluorescence revealed that Iba1 was highly expressed in the miR-27b-3p mimics group whereas it was poorly expressed in the miR-27b inhibitor group (Figure 4b).”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Interpretationown data

    miR-27b-3p promotes microglial inflammation and accelerates microglial apoptosis.

    “In general, miR-27b-3p promoted microglial inflammation and accelerated its apoptosis.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Interpretationown data

    The microglial cells were successfully isolated and the inflammation model of microglial cells was successfully constructed.

    “These findings indicated that the microglial cells were successfully isolated in this study and the inflammation model of microglial cells was successfully constructed.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Interpretationown data

    A20 inhibits microglial inflammation and apoptosis.

    “which revealed that A20 inhibited microglial inflammation and apoptosis.”
    • Also stated in: § Abstract · plain
      “Furthermore, A20 reduced microglial apoptosis.”
    Quote in the paperSubstantial claim
14 of 14
  • The paper relies on this without support.

    The LPS-induced microglial activation model is a valid model for neuroinflammation in cerebral hemorrhage and spinal cord injury.

    “Lipopolysaccharides (LPS) were used to prepare microglial activation models.”
    “We firstly used LPS to construct a microglia activation model, and induced neuroinflammation through this model.”
  • The paper relies on this without support.

    miR-27b-3p is related to A20 expression, as found in the authors' previous study.

    “And in our previous study, miR-27b-3p was found to be related to A20 expression.”
  • The paper relies on this without support.

    The effects of miR-27b-3p on microglial inflammation and apoptosis are mediated by downregulation of A20.

    “Then, we speculated that miR-27b-3p could negatively influence microglial cells which might be realized by reducing the expression of A20.”
    “It might increase the expression of inflammatory factors and promote microglial cell apoptosis by regulating A20, thus leading to the aggravation of neuroinflammation in microglial cells.”
3 of 3

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Luciferase assay names two different reporter vectors

    Major

    The methods say the A20 reporter used psiCHECK-2, while the results describe the validation assay as using pmirGLO-A20 constructs.

  • Figure 5 names a different miRNA for the target-validation result

    Minor

    The results attribute the A20 luciferase result to miR-27b-3p, but the Figure 5 caption attributes it to miR-129-5p. This changes which miRNA the target-validation result supports.

  • Mouse age differs between animal procurement and microglia isolation

    Minor

    The animals are described as 2-4 days old, but the isolation method specifies P0, the day of birth, as the age of the mice used for the primary cultures.

3 of 3

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Authors
Li, L., Qi, C., Liu, Y., Shen, Y., Zhao, X., Qin, H., Zhang, Y., & Yu, T.
Affiliations
  • Qingdao University (CN)
  • Affiliated Hospital of Qingdao University (CN)
Corresponding author
Yu, Tengbo
Venue
Bioengineered
Published
2021-12-13
Volume
12
Issue
2
Pages
9902-9913
ISSN
  • 2165-5979 (ISSN-L)
  • 2165-5987
OpenAlex
W4200210331
Cited by
29
References
41
Citations by year
2026: 4 · 2025: 10 · 2024: 8 · 2023: 2 · 2022: 5
FWCI
1.23
Type
journal article
Language
en
Open access
Locations
  • Bioengineered (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • PubMed Central (submittedVersion, cc-by)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
  • Figshare (submittedVersion, cc-by)
  • Figshare (cc-by)
Topics
  • Life Sciences › Neuroscience › Neurology › Neuroinflammation and Neurodegeneration Mechanisms
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cancer Research › MicroRNA in disease regulation
  • Health Sciences › Medicine › Neurology › Intracerebral and Subarachnoid Hemorrhage Research
Keywords
miR-27b-3p, A20, microglial activation, neuroinflammation, microglial apoptosis, TNF-α, interleukin-6, IL-1β, cerebral hemorrhage, spinal cord injury, lipopolysaccharide, microRNA target regulation
MeSH terms
Tumor Necrosis Factor alpha-Induced Protein 3, Animals, Inflammation, Male, Cytokines, Apoptosis, Microglia, MicroRNAs, Mice

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