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

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.

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

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.

scholarly journals TNFR1-dependent cell death drives inflammation in Sharpin-deficient mice

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
James A Rickard ◽  
Holly Anderton ◽  
Nima Etemadi ◽  
Ueli Nachbur ◽  
Maurice Darding ◽  
...  
Keyword(s):  
Cell Death ◽  
Transcriptional Activity ◽  
Peyer's Patches ◽  
Peyer’S Patches ◽  
Inflammatory Phenotype ◽  
Dependent Cell ◽  
Perinatal Lethality ◽  
Induced Apoptosis ◽  
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.

scholarly journals ­­LUBAC deficiency perturbs TLR3 signaling to cause immunodeficiency and autoinflammation

2016 ◽  
Vol 213 (12) ◽  
pp. 2671-2689 ◽  
Author(s):  
Julia Zinngrebe ◽  
Eva Rieser ◽  
Lucia Taraborrelli ◽  
Nieves Peltzer ◽  
Torsten Hartwig ◽  
...  
Keyword(s):  
Cell Death ◽  
Influenza A ◽  
Gene Activation ◽  
Ubiquitin Chain ◽  
Interacting Protein ◽  
Signaling Complex ◽  
Biochemical Level ◽  
Chronic Proliferative Dermatitis ◽  
Tlr3 Signaling

The linear ubiquitin chain assembly complex (LUBAC), consisting of SHANK-associated RH-domain–interacting protein (SHARPIN), heme-oxidized IRP2 ubiquitin ligase-1 (HOIL-1), and HOIL-1–interacting protein (HOIP), is a critical regulator of inflammation and immunity. This is highlighted by the fact that patients with perturbed linear ubiquitination caused by mutations in the Hoip or Hoil-1 genes, resulting in knockouts of these proteins, may simultaneously suffer from immunodeficiency and autoinflammation. TLR3 plays a crucial, albeit controversial, role in viral infection and tissue damage. We identify a pivotal role of LUBAC in TLR3 signaling and discover a functional interaction between LUBAC components and TLR3 as crucial for immunity to influenza A virus infection. On the biochemical level, we identify LUBAC components as interacting with the TLR3-signaling complex (SC), thereby enabling TLR3-mediated gene activation. Absence of LUBAC components increases formation of a previously unrecognized TLR3-induced death-inducing SC, leading to enhanced cell death. Intriguingly, excessive TLR3-mediated cell death, induced by double-stranded RNA present in the skin of SHARPIN-deficient chronic proliferative dermatitis mice (cpdm), is a major contributor to their autoinflammatory skin phenotype, as genetic coablation of Tlr3 substantially ameliorated cpdm dermatitis. Thus, LUBAC components control TLR3-mediated innate immunity, thereby preventing development of immunodeficiency and autoinflammation.

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

2014 ◽  
Author(s):  
James A Rickard ◽  
Holly Anderton ◽  
Nima Etemadi ◽  
Ueli Nachbur ◽  
Maurice Darding ◽  
...  
Keyword(s):  
Cell Death ◽  
Author Response ◽  
Dependent Cell ◽  
Deficient Mice

scholarly journals PLEKHO2 inhibits TNFα-induced cell death by suppressing RIPK1 activation

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

scholarly journals The death-inducing activity of RIPK1 is regulated by the pH environment

2020 ◽  
Vol 13 (631) ◽  
pp. eaay7066
Author(s):  
Kenta Moriwaki ◽  
Sakthi Balaji ◽  
Francis Ka-Ming Chan
Keyword(s):  
Cell Death ◽  
Ph Dependence ◽  
Proton Acceptor ◽  
Interacting Protein ◽  
Ph Changes ◽  
Signaling Complex ◽  
Inflammatory Stimuli ◽  
Acidic Extracellular Ph ◽  
Cytokine Tumor Necrosis Factor ◽  
Dependent Cell

Receptor-interacting protein kinase 1 (RIPK1) is a serine/threonine kinase that dictates whether cells survive or die in response to the cytokine tumor necrosis factor (TNF) and other inflammatory stimuli. The activity of RIPK1 is tightly controlled by multiple posttranslational modification mechanisms, including ubiquitination and phosphorylation. Here, we report that sensitivity to TNF-induced, RIPK1-dependent cell death was tunable by the pH environment. We found that an acidic extracellular pH, which led to a concomitant decrease in intracellular pH, impaired the kinase activation of RIPK1 and autophosphorylation at Ser166. Consequently, formation of the cytosolic death-inducing complex II and subsequent RIPK1-dependent necroptosis and apoptosis were inhibited. By contrast, low pH did not affect the formation of membrane-anchored TNFR1-containing signaling complex (complex I), RIPK1 ubiquitination, and NF-κB activation. TNF-induced cell death in Ripk1−/− cells was not sensitive to pH changes. Furthermore, mutation of the conserved His151 abolished the pH dependence of RIPK1 activation, suggesting that this histidine residue functions as a proton acceptor to modulate RIPK1 activity in response to pH changes. These results revealed an unexpected environmental factor that controls the death-inducing activity of RIPK1.

scholarly journals Differential roles of Yersinia outer protein P-mediated inhibition of nuclear factor-kappa B in the induction of cell death in dendritic cells and macrophages

2008 ◽  
Vol 57 (2) ◽  
pp. 139-144 ◽  
Author(s):  
Irena Adkins ◽  
Sebastian Schulz ◽  
Stefan Borgmann ◽  
Ingo B. Autenrieth ◽  
Sabine Gröbner
Keyword(s):  
Cell Death ◽  
Dendritic Cells ◽  
Nuclear Factor Kappa B ◽  
Nuclear Factor ◽  
Iodide Uptake ◽  
Nuclear Factor Kappa ◽  
Dependent Inhibition ◽  
Mitogen Activated Protein ◽  
Dependent Cell ◽  
Antigen Presenting

Yersinia outer protein P (YopP) induces cell death in macrophages and dendritic cells (DC). In DC this YopP-dependent cell death coincides with the inhibition of nuclear factor-kappa B (NF-κB) activation. However, as shown by measurement of propidium iodide uptake via disrupted cellular membranes, the preincubation of DC with several NF-κB inhibitors prior to infection with Yersinia did not restore the death-inducing capacity of a YopP-deficient Yersinia mutant. These results suggest that in contrast to macrophages, in DC the YopP-dependent inhibition of NF-κB activation is not causative for the induction of cell death. Instead, in DC, the inhibition of mitogen-activated protein kinases (MAPKs), in particular, p38 and c-Jun N-terminal kinase, prior to infection with a YopP-deficient Yersinia mutant substituted the death-inducing capacity of the Yersinia wild-type strain, indicating that the YopP-dependent inhibition of MAPKs mediates Yersinia-induced DC death. The differences between DC and macrophages in the mechanisms of cell death induction by YopP presented herein might be crucial for the function of these antigen-presenting cells.

scholarly journals Serine 165 Phosphorylation of SHARPIN regulates the Activation of NF-κB

2020 ◽  
Author(s):  
An Thys ◽  
Kilian Trillet ◽  
Sara Rosinska ◽  
Audrey Gayraud ◽  
Tiphaine Douanne ◽  
...  
Keyword(s):  
Cell Death ◽  
T Cell Receptor ◽  
Resistant Mutant ◽  
Cell Receptor ◽  
Receptor Stimulation ◽  
Ubiquitin Chain ◽  
E3 Ligases ◽  
Signaling Complex ◽  
New Strategies ◽  
Enzymatic Complex

AbstractThe adaptor SHARPIN composes, together with the E3 ligases HOIP and HOIL1, the linear ubiquitin chain assembly complex. This enzymatic complex catalyzes and stamps atypical linear ubiquitin chains onto substrates to modify their fate, and has been linked to the regulation of the NF-κB pathway downstream most immunoreceptors, inflammation and cell death. However, how this signaling complex is regulated is not fully understood. Here, we report that a portion of SHARPIN is constitutively phosphorylated on the serine in position 165 in lymphoblastoid cells, and can be further induced following antigen receptor stimulation. Analysis of a phosphorylation-resistant mutant of SHARPIN revealed that this mark is dispensable for the generation of linear ubiquitin chains. However, phosphorylation allows the optimal activation of NF-κB in response to TNFα and T-cell receptor engagement. These results identify a new layer of regulation of the LUBAC, and unveil new strategies to modulate its action.

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