Decision letter: TNFR1-dependent cell death drives inflammation in Sharpin-deficient mice

SHARPIN regulates immune signaling and contributes to full transcriptional activity and prevention of cell death in response to TNF in vitro. The inactivating mouse Sharpin cpdm mutation causes TNF-dependent multi-organ inflammation, characterized by dermatitis, liver inflammation, splenomegaly, and loss of Peyer's patches. TNF-dependent cell death has been proposed to cause the inflammatory phenotype and consistent with this we show Tnfr1, but not Tnfr2, deficiency suppresses the phenotype (and it does so more efficiently than Il1r1 loss). TNFR1-induced apoptosis can proceed through caspase-8 and BID, but reduction in or loss of these players generally did not suppress inflammation, although Casp8 heterozygosity significantly delayed dermatitis. Ripk3 or Mlkl deficiency partially ameliorated the multi-organ phenotype, and combined Ripk3 deletion and Casp8 heterozygosity almost completely suppressed it, even restoring Peyer's patches. Unexpectedly, Sharpin, Ripk3 and Casp8 triple deficiency caused perinatal lethality. These results provide unexpected insights into the developmental importance of SHARPIN.

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Immune dysregulation in SHARPIN-deficient mice is dependent on CYLD-mediated cell death

10.1101/2020.01.27.919076 ◽

2020 ◽

Author(s):

Rosalind L. Ang ◽

John P. Sundberg ◽

Shao-Cong Sun ◽

Virginia L. Gillespie ◽

Peter S. Heeger ◽

...

Keyword(s):

Cell Death ◽

Immune Dysregulation ◽

Ubiquitin Chain ◽

Physiological Conditions ◽

Signaling Complex ◽

Conditional Deletion ◽

Short Summary ◽

Dependent Inhibition ◽

Dependent Cell ◽

Deficient Mice

AbstractSHARPIN, together with RNF31/HOIP and RBCK1/HOIL1, form the linear ubiquitin chain assembly complex (LUBAC) E3 ligase that catalyzes M1-linked poly-ubiquitination. Mutations in RNF31/HOIP and RBCK/HOIL1 in humans and Sharpin in mice lead to auto-inflammation and immunodeficiency but the mechanism underlying the immune dysregulation remains unclear. We now show that the phenotype of the Sharpin-/- mice is dependent on CYLD, the deubiquitinase that removes K63-linked poly-ubiquitin chains. The dermatitis, disrupted splenic architecture, and loss of Peyer’s patches in the Sharpin-/- mice were fully reversed in Sharpin-/-Cyld-/- mice. There is enhanced association of RIPK1 with the death-inducing signaling complex (DISC) following TNF stimulation in Sharpin-/- cells, and this is dependent on CYLD since it is reversed in Sharpin-/-Cyld-/- cells. Enhanced RIPK1 recruitment to the DISC in Sharpin-/- cells correlated with impaired phosphorylation of CYLD at serine 418, a modification reported to inhibit its enzymatic activity. The dermatitis in the Sharpin-/- mice was also ameliorated by the conditional deletion of Cyld using LysM-cre or Cx3cr1-cre indicating that CYLD-dependent death of myeloid cells is inflammatory. Our studies reveal that under physiological conditions, TNF- and RIPK1-dependent cell death is suppressed by the linear ubiquitin-dependent inhibition of CYLD. The Sharpin-/- phenotype illustrates the pathological consequences when CYLD inhibition fails.Short SummaryIn the absence of SHARPIN, cells fail to properly regulate the deubiquitinase CYLD, leading to RIPK1-mediated cell death. Deletion of Cyld reverses the sensitivity of Sharpin-/- cells to TNF-induced cell death, as well as the multi-organ inflammation and immune dysfunction observed in Sharpin-/- mice.

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Author response: TNFR1-dependent cell death drives inflammation in Sharpin-deficient mice

10.7554/elife.03464.016 ◽

2014 ◽

Cited By ~ 1

Author(s):

James A Rickard ◽

Holly Anderton ◽

Nima Etemadi ◽

Ueli Nachbur ◽

Maurice Darding ◽

...

Keyword(s):

Cell Death ◽

Author Response ◽

Dependent Cell ◽

Deficient Mice

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PLEKHO2 inhibits TNFα-induced cell death by suppressing RIPK1 activation

Cell Death and Disease ◽

10.1038/s41419-021-04001-2 ◽

2021 ◽

Vol 12 (8) ◽

Author(s):

Chenchen Zhou ◽

Xueli Zhang ◽

Cuiping Yang ◽

Yuan He ◽

Luo Zhang

Keyword(s):

Cell Death ◽

Kinase Inhibitor ◽

Receptor Interaction ◽

Ph Domain ◽

Tnf Α ◽

Dependent Cell ◽

Induced Apoptosis ◽

Factor Α ◽

Deficient Mice ◽

Necrosis Factor

AbstractReceptor interaction protein kinase 1 (RIPK1) plays a diverse role in tumor necrosis factor α (TNFα) signalings. The ubiquitination of RIPK1 is essential for NF-κB activation, whereas its kinase activity promotes apoptosis and necroptosis. However, the mechanisms underlying have not been fully illuminated. Here we report that PH domain-containing family O member 2 (PLEKHO2) inhibits RIPK1-dependent cell death and is necessary for NF-κB activation in response to TNFα. Cells of PLKEHO2 deficiency are more susceptible to TNF-α induced apoptosis and necroptosis with increased RIPK1 activation, which is consistent with the observation that the susceptibility of PLEKHO2−/− cells is effectively prevented by treatment of RIPK1 kinase inhibitor. Moreover, PLEKHO2 deficient cells exhibit compromised RIPK1 ubiquitination and NF-κB activation in response to TNFα. Ultimately, PLEKHO2-deficient mice display greatly increased hepatotoxicity and lethality after TNFα-induced hepatitis. In summary, our study revealed that PLEKHO2 is a novel inhibitor of apoptosis and necroptosis, which plays a key role in regulating RIPK1 ubiquitination and activation

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Immune dysregulation in SHARPIN-deficient mice is dependent on CYLD-mediated cell death

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2001602118 ◽

2021 ◽

Vol 118 (50) ◽

pp. e2001602118

Author(s):

Rosalind L. Ang ◽

Mark Chan ◽

Diana Legarda ◽

John P. Sundberg ◽

Shao-Cong Sun ◽

...

Keyword(s):

Cell Death ◽

Immune Dysregulation ◽

Ubiquitin Chain ◽

Polyubiquitin Chains ◽

Complex Ii ◽

Signaling Complex ◽

Conditional Deletion ◽

Dependent Inhibition ◽

Dependent Cell ◽

Deficient Mice

SHARPIN, together with RNF31/HOIP and RBCK1/HOIL1, form the linear ubiquitin chain assembly complex (LUBAC) E3 ligase that catalyzes M1-linked polyubiquitination. Mutations in RNF31/HOIP and RBCK/HOIL1 in humans and Sharpin in mice lead to autoinflammation and immunodeficiency, but the mechanism underlying the immune dysregulation remains unclear. We now show that the phenotype of the Sharpincpdm/cpdm mice is dependent on CYLD, a deubiquitinase previously shown to mediate removal of K63-linked polyubiquitin chains. Dermatitis, disrupted splenic architecture, and loss of Peyer's patches in the Sharpincpdm/cpdm mice were fully reversed in Sharpincpdm/cpdm Cyld−/− mice. We observed enhanced association of RIPK1 with the death-signaling Complex II following TNF stimulation in Sharpincpdm/cpdm cells, a finding dependent on CYLD since we observed reversal in Sharpincpdm/cpdm Cyld−/− cells. Enhanced RIPK1 recruitment to Complex II in Sharpincpdm/cpdm cells correlated with impaired phosphorylation of CYLD at serine 418, a modification reported to inhibit its enzymatic activity. The dermatitis in the Sharpincpdm/cpdm mice was also ameliorated by the conditional deletion of Cyld using LysM-cre or Cx3cr1-cre indicating that CYLD-dependent death of myeloid cells is inflammatory. Our studies reveal that under physiological conditions, TNF- and RIPK1-dependent cell death is suppressed by the linear ubiquitin-dependent inhibition of CYLD. The Sharpincpdm/cpdm phenotype illustrates the pathological consequences when CYLD inhibition fails.

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