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Introduction

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Examination of universally expressed circRNAs

Treated HeLa cells with 8 stressors followed by the examination of universally expressed circRNAs

circRNAs are degraded upon Poly I:C treatment

Global reduction of high confidence circRNAs upon poly(I:C) for 6 h (C) or EMCV for 24 h

circRNAs are degraded upon Poly I:C treatment

Treated HeLa cells with 8 stressors followed by the examination of universally expressed circRNAs

circRNAs are degraded upon Poly I:C treatment

Treated HeLa cells with 8 stressors followed by the examination of universally expressed circRNAs

circRNAs are degraded upon Poly I:C treatment

Global reduction of high confidence circRNAs upon poly(I:C) for 6 h (C) or EMCV for 24 h

circRNAs are degraded upon Poly I:C treatment

Global reduction of high confidence circRNAs upon poly(I:C) for 6 h (C) or EMCV for 24 h

circRNAs are degraded upon Poly I:C treatment

Treated HeLa cells with 8 stressors followed by the examination of universally expressed circRNAs

circRNAs are degraded upon Poly I:C treatment

Global reduction of high confidence circRNAs upon poly(I:C) for 6 h (C) or EMCV for 24 h

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RNase L “may” be responsible for circRNA degradation upon poly(I:C) and viral stimulations

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RNase L “may” be responsible for circRNA degradation upon poly(I:C) and viral stimulations

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RNase L “may” be responsible for circRNA degradation upon poly(I:C) and viral stimulations

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RNase L is responsible for global circRNA degradation in cells treated with poly(I:C)

The endonuclease activity of RNase L is requiredfor circRNA degradation

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The endonuclease activity of RNase L is requiredfor circRNA degradation

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The endonuclease activity of RNase L is requiredfor circRNA degradation

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The endonuclease activity of RNase L is requiredfor circRNA degradation

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In vitro binding and competition screening assays with purified immune factors

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In vitro binding and competition screening assays with purified immune factors

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In vitro binding and competition screening assays with purified immune factors

circRNAs prefer to bind to nucleic acid receptors with antiviral activity

circRNAs prefer to bind to nucleic acid receptors with antiviral activity

circRNAs prefer to bind to nucleic acid receptors with antiviral activity

circRNAs prefer to bind to nucleic acid receptors with antiviral activity

dsRBMs of PKR are required for binding to circPOLR2A

circRNAs prefer to bind to nucleic acid receptors with antiviral activity

dsRBMs of PKR are required for binding to circPOLR2A

circRNAs prefer to bind to nucleic acid receptors with antiviral activity

circRNAs prefer to bind to nucleic acid receptors with antiviral activity

circRNAs prefer to bind to nucleic acid receptors with antiviral activity

dsRBMs of PKR are required for binding to circPOLR2A

circRNAs prefer to bind to nucleic acid receptors with antiviral activity

dsRBMs of PKR are required for binding to circPOLR2A

PKR is an IFN-inducible Ser/Thr protein kinase directly activated by dsRNA

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Comparison of paired circular and linear RNA structures by SHAPE-MaP

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Comparison of paired circular and linear RNA structures by SHAPE-MaP

Linear POLR2A is relatively unstructured within circPOLR2A-forming region

circRNAs have distinct structural conformation from their linear cognate RNAs

Many examined circRNAs tend to form imperfect duplex RNA regions

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Most examined circRNAs could form 1–4 dsRNA regions.Hypothesis : Per cell may contains > 10,000~20,000 intra-dsRNA regions and that such circRNAs represent a type of endogenous inhibitors for PKR.

Overexpression of circRNAs in Hela cell

Most examined circRNAs could form 1–4 dsRNA regions.Hypothesis : Per cell may contains > 10,000~20,000 intra-dsRNA regions and that such circRNAs represent a type of endogenous inhibitors for PKR.

Overexpression of circRNAs in Hela cell

Overexpression of circPOLR2A in HeLa cells inhibits PKR phosphorylation upon poly(I:C) stimulation

Overexpression of the non-dsRNA-containing circRNA in HeLa cells does not suppress PKR phosphorylation upon poly(I:C) stimulation.

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Reduced PKR activation in RNase L KO HeLa cells stimulated with poly(I:C)

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Reduced PKR activation in RNase L KO HeLa cells stimulated with poly(I:C)

Overexpression of circPOLR2A in HeLa cells inhibitsPKR phosphorylation upon EMCV infection

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Dysregulated circRNA expression and PKR activation in SLE

circRNA reduction in PBMCs derived from SLE patients

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Global reduction of circRNA expression in SLE patients (RNA-seq)

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circPOLR2A overexpression attenuates aberrant PKR and EIF2α phosphorylation in PBMCs isolated from three SLE patients

circPOLR2A overexpression attenuates aberrant PKR and EIF2α phosphorylation in T cells isolated from three SLE patients

circPOLR2A overexpression attenuates aberrant PKR and EIF2α phosphorylation in PBMCs isolated from three SLE patients

circPOLR2A overexpression attenuates aberrant PKR and EIF2α phosphorylation in T cells isolated from three SLE patients

circPOLR2A overexpression attenuates aberrant PKR and EIF2α phosphorylation in PBMCs isolated from three SLE patients

circPOLR2A overexpression attenuates aberrant PKR and EIF2α phosphorylation in T cells isolated from three SLE patients

Conclusion

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Highlights

circPOLR2A overexpression attenuates aberrant PKR and EIF2α phosphorylation in PBMCs isolated from three SLE patients