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ShRNAs targeting mouse Adam10 diminish cell response to proinflammatory stimuli independently of Adam10 silencing.

ABSTRACT: RNA interference is one of the common methods of studying protein functions. In recent years critical reports have emerged indicating that off-target effects may have a much greater impact on RNAi-based analysis than previously assumed. We studied the influence of Adam10 and Adam17 silencing on MC38CEA cell response to proinflammatory stimuli. Eight lentiviral vector-encoded shRNAs that reduced ADAM10 expression, including two that are specific towards ADAM17, caused inhibition of cytokine-induced Nos2 expression presumably via off-target effects. ADAM10 silencing was not responsible for this effect because: (i) CRISPR/Cas9 knockdown of ADAM10 did not affect Nos2 levels; (ii) ADAM10 inhibitor increased rather than decreased Nos2 expression; (iii) overexpression of ADAM10 in the cells with shRNA-silenced Adam10 did not reverse the effect induced by shRNA; (iv) shRNA targeting ADAM10 resulted in decrease of Nos2 expression even in ADAM10-deficient cells. The studied shRNAs influenced transcription of Nos2 rather than stability of Nos2 mRNA. They also affected stimulation of Ccl2 and Ccl7 expression. Additionally, we used vectors with doxycycline-inducible expression of chosen shRNAs and observed reduced activation of NF-κB and, to a lesser extent, AP-1 transcription factors. We discuss the requirements of strict controls and verification of results with complementary methods for reliable conclusions of shRNA-based experiments.

SUBMITTER: Czarnek M

PROVIDER: S-EPMC8905717 | biostudies-literature | 2022 Mar

REPOSITORIES: biostudies-literature

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shRNAs targeting mouse Adam10 diminish cell response to proinflammatory stimuli independently of Adam10 silencing.

Czarnek Maria M Stalińska Krystyna K Sarad Katarzyna K Bereta Joanna J

Biology open 20220304 3

RNA interference is one of the common methods of studying protein functions. In recent years critical reports have emerged indicating that off-target effects may have a much greater impact on RNAi-based analysis than previously assumed. We studied the influence of Adam10 and Adam17 silencing on MC38CEA cell response to proinflammatory stimuli. Eight lentiviral vector-encoded shRNAs that reduced ADAM10 expression, including two that are specific towards ADAM17, caused inhibition of cytokine-induc ...[more]

PMID: 35107128

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Project description:Bacterial infections can induce exuberant immune responses that can damage host tissues. Previously, we demonstrated that systemic Escherichia coli infection in mice causes tissue damage in the liver. This liver necrosis is associated with the expression of endogenous retroviruses, chromosomally integrated retroviruses that encode a reverse transcriptase. Furthermore, nucleotide/nucleoside reverse transcriptase inhibitors (NRTIs) completely prevent tissue damage and subsequent bacterial growth within necrotic lesions. Since liver necrosis is linked to heightened systemic inflammatory responses, we hypothesized that NRTIs diminish inflammation caused by E. coli infection and may also have broad impacts on the systemic immune response to bacterial pathogens. Here, we tested this hypothesis by characterizing the effects of NRTIs on the innate immune response to bacteria. In the liver, NRTI administration following E. coli inoculation reduced the expression of a large repertoire of proinflammatory transcripts. NRTIs also had systemic anti-inflammatory effects, including reducing proinflammatory cytokine levels in serum in response to E. coli in different mouse strains. The anti-inflammatory effects of NRTIs were also apparent in response to lipopolysaccharide (LPS) and Staphylococcus aureus, suggesting that the molecular mechanisms underlying the immunomodulatory functions of NRTIs are likely conserved across distinct immune signaling pathways. Moreover, in a model of lethal LPS shock, NRTI administration prevented hypothermia and death. Together, our observations reveal that NRTIs can potently impede systemic inflammatory responses during Gram-positive and Gram-negative bacterial infections. Our findings lay the groundwork for further investigation of the therapeutic scope of NRTIs and the mechanisms underlying their anti-inflammatory effects across non-retroviral infectious diseases.IMPORTANCEInflammatory responses are critical for host control of bacterial infection, but excessive inflammation can damage host tissues and lead to sepsis. Understanding how innate immune responses are controlled during infection is important for developing new approaches to dampen excessive inflammation. In previous work, we found that tissue damage caused by excessive inflammatory responses may be driven by endogenous reverse transcriptases. Here we demonstrate that treatment of mice with reverse transcriptase inhibitors leads to broad reductions in systemic proinflammatory responses during bacterial infections and can protect mice from acute death in a lethal model of sepsis. Our findings indicate that uncovering the mechanisms underlying the anti-inflammatory functions of reverse transcriptase inhibitors may lead to new therapeutics for bacterial infectious diseases.

Project description:AimTo investigate transcriptional gene silencing induced by short hairpin RNAs (shRNAs) that target gene prompter regions of RUNX3 gene, and whether shRNAs homologous to DNA sequences may serve as initiators for methylation.MethodsAccording to the principle of RNAi design, pSilencer3.1-H1-shRNA/RUNX3 expression vector was constructed, The recombinant plasmid shRNA was transfected into human stomach carcinoma cell line SGC7901 with Lipofectamine 2000. Then, the positive cell clones were screened by G418. The mRNA and protein expression level of RUNX3 in the stable transfected cell line SGC7901 were determined by RT-PCR, Western blotting and immunocytochemistry. Characteristics of the cell lines including SGC7901, pSilencer3.1-H1/SGC7901 and pSilencer3.1-H1-shRNA/RUNX3/SGC7901 were analyzed with growth curves, clone formation rate and cell-cycle distribution. The activated level of RUNX3 was examined after treatment with the different density of 5'-aza-2'-deoxycytidine (5-Aza-CdR) by using semi-quantitative RT-PCR and Western blotting.ResultsIn the cell line SGC7901 transfected with pSilencer3.1-H1-shRNA/RUNX3, mRNA and protein expression of the RUNX3 gene was lost identified by RT-PCR, Western blotting and immunocytochemistry assay. The growth of pSilencer3.1-H1-shRNA/ RUNX3/SGC7901 cells without expression of RUNX3 was the fastest (P < 0.05), its rate of clone formation was the highest (P < 0.01), and the cell distribution in G(0)/G(1) and S/M phases was lowest and highest, respectively (P < 0.05), compared with that of the transfected pSilencer3.1-H1 and non-transfected cells. Through RT-PCR and Western blot assay, inactivated RUNX3 could not be reactivated by 5-Aza-CdR.ConclusionWe found that, although shRNAs targeted to gene prompter regions of RUNX3 could effectively induce transcriptional repression with chromatic changes characteristic of inaction promoters, this was independent of DNA methylation, and the presence of RNA-dependent transcriptional silencing showed that RNA-directed DNA methylation might be an existing gene regulatory mechanism relative to the methylated in humans.

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ShRNAs targeting mouse Adam10 diminish cell response to proinflammatory stimuli independently of Adam10 silencing.

Publications

shRNAs targeting mouse Adam10 diminish cell response to proinflammatory stimuli independently of Adam10 silencing.

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