scholarly journals Impaired RIPK1 ubiquitination sensitizes mice to TNF toxicity and inflammatory cell death

2020 ◽  
Author(s):  
Matthias Kist ◽  
László G. Kőműves ◽  
Tatiana Goncharov ◽  
Debra L. Dugger ◽  
Charles Yu ◽  
...  
Keyword(s):  
Cell Death ◽  
Inflammatory Responses ◽  
Mapk Signaling ◽  
Embryonic Lethality ◽  
Mapk Activation ◽  
Interacting Protein ◽  
Signaling Complex ◽  
Ubiquitination Site ◽  
Lysine Residues ◽  
The Stability

Abstract Receptor-interacting protein 1 (RIP1; RIPK1) is a key regulator of multiple signaling pathways that mediate inflammatory responses and cell death. TNF-TNFR1 triggered signaling complex formation, subsequent NF-κB and MAPK activation and induction of cell death involve RIPK1 ubiquitination at several lysine residues including Lys376 and Lys115. Here we show that mutating the ubiquitination site K376 of RIPK1 (K376R) in mice activates cell death resulting in embryonic lethality. In contrast to Ripk1K376R/K376R mice, Ripk1K115R/K115R mice reached adulthood and showed slightly higher responsiveness to TNF-induced death. Cell death observed in Ripk1K376R/K376R embryos relied on RIPK1 kinase activity as administration of RIPK1 inhibitor GNE684 to pregnant heterozygous mice effectively blocked cell death and prolonged survival. Embryonic lethality of Ripk1K376R/K376R mice was prevented by the loss of TNFR1, or by simultaneous deletion of caspase-8 and RIPK3. Interestingly, elimination of the wild-type allele from adult Ripk1K376R/cko mice was tolerated. However, adult Ripk1K376R/cko mice were exquisitely sensitive to TNF-induced hypothermia and associated lethality. Absence of the K376 ubiquitination site diminished K11-linked, K63-linked, and linear ubiquitination of RIPK1, and promoted the assembly of death-inducing cellular complexes, suggesting that multiple ubiquitin linkages contribute to the stability of the RIPK1 signaling complex that stimulates NF-κB and MAPK activation. In contrast, mutating K115 did not affect RIPK1 ubiquitination or TNF stimulated NF-κB and MAPK signaling. Overall, our data indicate that selective impairment of RIPK1 ubiquitination can lower the threshold for RIPK1 activation by TNF resulting in cell death and embryonic lethality.

scholarly journals SMAC mimetics induce autophagy-dependent apoptosis of HIV-1-infected macrophages

2020 ◽  
Vol 11 (7) ◽  
Author(s):  
Grant R. Campbell ◽  
Rachel K. To ◽  
Gang Zhang ◽  
Stephen A. Spector
Keyword(s):  
Cell Death ◽  
Hiv Infection ◽  
Cell Survival ◽  
Acute Hiv Infection ◽  
Interacting Protein ◽  
Signaling Complex ◽  
Hiv Eradication ◽  
Smac Mimetics ◽  
Smac Mimetic ◽  
Latent Hiv

Abstract Human immunodeficiency type 1 (HIV)-infected macrophages (HIV-Mφ) are a reservoir for latent HIV infection and a barrier to HIV eradication. In contrast to CD4+ T cells, HIV-Mφ are resistant to the cytopathic effects of acute HIV infection and have increased expression of cell survival factors, including X-linked inhibitor of apoptosis (XIAP), baculoviral IAP repeat containing (BIRC) 2/cIAP1, beclin-1, BCL2, BCL-xl, triggering receptor expressed on myeloid cells 1, mitofusin (MFN) 1, and MFN2. DIABLO/SMAC mimetics are therapeutic agents that affect cancer cell survival and induce cell death. We found that DIABLO/SMAC mimetics (LCL-161, AT-406 (also known as SM-406 or Debio 1143), and birinapant) selectively kill HIV-Mφ without increasing bystander cell death. DIABLO/SMAC mimetic treatment of HIV-Mφ-induced XIAP and BIRC2 degradation, leading to the induction of autophagy and the formation of a death-inducing signaling complex on phagophore membranes that includes both pro-apoptotic or necroptotic (FADD, receptor-interacting protein kinase (RIPK) 1, RIPK3, caspase 8, and MLKL) and autophagy (ATG5, ATG7, and SQSTM1) proteins. Genetic or pharmacologic inhibition of early stages of autophagy, but not late stages of autophagy, ablated this interaction and inhibited apoptosis. Furthermore, DIABLO/SMAC mimetic-mediated apoptosis of HIV-Mφ is dependent upon tumor necrosis factor signaling. Our findings thus demonstrate that DIABLO/SMAC mimetics selectively induce autophagy-dependent apoptosis in HIV-Mφ.

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 Necroptosis in Pulmonary Diseases: A New Therapeutic Target

2021 ◽  
Vol 12 ◽  
Author(s):  
Lingling Wang ◽  
Ling Zhou ◽  
Yuhao Zhou ◽  
Lu Liu ◽  
Weiling Jiang ◽  
...  
Keyword(s):  
Cell Death ◽  
Plasma Membranes ◽  
Inflammatory Responses ◽  
Neurological Diseases ◽  
Kinase Domain ◽  
The Body ◽  
Interacting Protein ◽  
Membrane Rupture ◽  
Regulated Cell Death ◽  
Scientific Attention

In the past decades, apoptosis has been the most well-studied regulated cell death (RCD) that has essential functions in tissue homeostasis throughout life. However, a novel form of RCD called necroptosis, which requires receptor-interacting protein kinase-3 (RIPK3) and mixed-lineage kinase domain-like pseudokinase (MLKL), has recently been receiving increasing scientific attention. The phosphorylation of RIPK3 enables the recruitment and phosphorylation of MLKL, which oligomerizes and translocates to the plasma membranes, ultimately leading to plasma membrane rupture and cell death. Although apoptosis elicits no inflammatory responses, necroptosis triggers inflammation or causes an innate immune response to protect the body through the release of damage-associated molecular patterns (DAMPs). Increasing evidence now suggests that necroptosis is implicated in the pathogenesis of several human diseases such as systemic inflammation, respiratory diseases, cardiovascular diseases, neurodegenerative diseases, neurological diseases, and cancer. This review summarizes the emerging insights of necroptosis and its contribution toward the pathogenesis of lung diseases.

scholarly journals Autophagy genes in myeloid cells counteract IFNγ-induced TNF-mediated cell death and fatal TNF-induced shock

2019 ◽  
Vol 116 (33) ◽  
pp. 16497-16506 ◽  
Author(s):  
Anthony Orvedahl ◽  
Michael R. McAllaster ◽  
Amy Sansone ◽  
Bria F. Dunlap ◽  
Chandni Desai ◽  
...  
Keyword(s):  
Cell Death ◽  
Cell Survival ◽  
Inflammatory Responses ◽  
Tissue Injury ◽  
Survival Function ◽  
Myeloid Cell ◽  
Critical Function ◽  
Interacting Protein ◽  
Autophagy Gene ◽  
Genome Wide

Host inflammatory responses must be tightly regulated to ensure effective immunity while limiting tissue injury. IFN gamma (IFNγ) primes macrophages to mount robust inflammatory responses. However, IFNγ also induces cell death, and the pathways that regulate IFNγ-induced cell death are incompletely understood. Using genome-wide CRISPR/Cas9 screening, we identified autophagy genes as central mediators of myeloid cell survival during the IFNγ response. Hypersensitivity of autophagy gene-deficient cells to IFNγ was mediated by tumor necrosis factor (TNF) signaling via receptor interacting protein kinase 1 (RIPK1)- and caspase 8-mediated cell death. Mice with myeloid cell-specific autophagy gene deficiency exhibited marked hypersensitivity to fatal systemic TNF administration. This increased mortality in myeloid autophagy gene-deficient mice required the IFNγ receptor, and mortality was completely reversed by pharmacologic inhibition of RIPK1 kinase activity. These findings provide insight into the mechanism of IFNγ-induced cell death via TNF, demonstrate a critical function of autophagy genes in promoting cell viability in the presence of inflammatory cytokines, and implicate this cell survival function in protection against mortality during the systemic inflammatory response.

scholarly journals The E3 Ubiquitin-Protein Ligase RNF4 Promotes TNF-α-Induced Cell Death Triggered by RIPK1

2021 ◽  
Vol 22 (11) ◽  
pp. 5796
Author(s):  
Tatsuya Shimada ◽  
Yuki Kudoh ◽  
Takuya Noguchi ◽  
Tomohiro Kagi ◽  
Midori Suzuki ◽  
...  
Keyword(s):  
Cell Death ◽  
Posttranslational Modifications ◽  
Transforming Growth Factor ◽  
Ring Finger ◽  
Transforming Growth Factor Β ◽  
Nuclear Factor Κb ◽  
Interacting Protein ◽  
Signaling Complex ◽  
Enhanced Sensitivity ◽  
Tnf Α

Receptor-interacting protein kinase 1 (RIPK1) is a key component of the tumor necrosis factor (TNF) receptor signaling complex that regulates both pro- and anti-apoptotic signaling. The reciprocal functions of RIPK1 in TNF signaling are determined by the state of the posttranslational modifications (PTMs) of RIPK1. However, the underlying mechanisms associated with the PTMs of RIPK1 are unclear. In this study, we found that RING finger protein 4 (RNF4), a RING finger E3 ubiquitin ligase, is required for the RIPK1 autophosphorylation and subsequent cell death. It has been reported that RNF4 negatively regulates TNF-α-induced activation of the nuclear factor-κB (NF-κB) through downregulation of transforming growth factor β-activated kinase 1 (TAK1) activity, indicating the possibility that RNF4-mediated TAK1 suppression results in enhanced sensitivity to cell death. However, interestingly, RNF4 was needed to induce RIPK1-mediated cell death even in the absence of TAK1, suggesting that RNF4 can promote RIPK1-mediated cell death without suppressing the TAK1 activity. Thus, these observations reveal the existence of a novel mechanism whereby RNF4 promotes the autophosphorylation of RIPK1, which provides a novel insight into the molecular basis for the PTMs of RIPK1.

scholarly journals Receptor-interacting protein kinase 1 is a key mediator in TLR3 ligand and Smac mimetic-induced cell death and suppresses TLR3 ligand-promoted invasion in cholangiocarcinoma

2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Thanpisit Lomphithak ◽  
Swati Choksi ◽  
Apiwat Mutirangura ◽  
Rutaiwan Tohtong ◽  
Tewin Tencomnao ◽  
...  
Keyword(s):  
Cell Death ◽  
Protein Kinase ◽  
Cell Lines ◽  
Mapk Signaling ◽  
Poly I:C ◽  
Interacting Protein ◽  
Smac Mimetic ◽  
Tlr3 Signaling ◽  
Tlr3 Ligand Poly

Abstract Background Toll-like receptor 3 (TLR3) ligand which activates TLR3 signaling induces both cancer cell death and activates anti-tumor immunity. However, TLR3 signaling can also harbor pro-tumorigenic consequences. Therefore, we examined the status of TLR3 in cholangiocarcinoma (CCA) cases to better understand TLR3 signaling and explore the potential therapeutic target in CCA. Methods The expression of TLR3 and receptor-interacting protein kinase 1 (RIPK1) in primary CCA tissues was assayed by Immunohistochemical staining and their associations with clinicopathological characteristics and survival data were evaluated. The effects of TLR3 ligand, Poly(I:C) and Smac mimetic, an IAP antagonist on CCA cell death and invasion were determined by cell death detection methods and Transwell invasion assay, respectively. Both genetic and pharmacological inhibition of RIPK1, RIPK3 and MLKL and inhibitors targeting NF-κB and MAPK signaling were used to investigate the underlying mechanisms. Results TLR3 was significantly higher expressed in tumor than adjacent normal tissues. We demonstrated in a panel of CCA cell lines that TLR3 was frequently expressed in CCA cell lines, but was not detected in a nontumor cholangiocyte. Subsequent in vitro study demonstrated that Poly(I:C) specifically induced CCA cell death, but only when cIAPs were removed by Smac mimetic. Cell death was also switched from apoptosis to necroptosis when caspases were inhibited in CCA cells-expressing RIPK3. In addition, RIPK1 was required for Poly(I:C) and Smac mimetic-induced apoptosis and necroptosis. Of particular interest, high TLR3 or low RIPK1 status in CCA patients was associated with more invasiveness. In vitro invasion demonstrated that Poly(I:C)-induced invasion through NF-κB and MAPK signaling. Furthermore, the loss of RIPK1 enhanced Poly(I:C)-induced invasion and ERK activation in vitro. Smac mimetic also reversed Poly(I:C)-induced invasion, partly mediated by RIPK1. Finally, a subgroup of patients with high TLR3 and high RIPK1 had a trend toward longer disease-free survival (p = 0.078, 28.0 months and 10.9 months). Conclusion RIPK1 plays a pivotal role in TLR3 ligand, Poly(I:C)-induced cell death when cIAPs activity was inhibited and loss of RIPK1 enhanced Poly(I:C)-induced invasion which was partially reversed by Smac mimetic. Our results suggested that TLR3 ligand in combination with Smac mimetic could provide therapeutic benefits to the patients with CCA. Graphical abstract

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 Cellular IAPs inhibit a cryptic CD95-induced cell death by limiting RIP1 kinase recruitment

2009 ◽  
Vol 187 (7) ◽  
pp. 1037-1054 ◽  
Author(s):  
Peter Geserick ◽  
Mike Hupe ◽  
Maryline Moulin ◽  
W. Wei-Lynn Wong ◽  
Maria Feoktistova ◽  
...  
Keyword(s):  
Cell Death ◽  
Death Receptor ◽  
Physiological Role ◽  
Inhibitory Protein ◽  
Interacting Protein ◽  
Complex Ii ◽  
Signaling Complex ◽  
Iap Antagonist ◽  
Cellular Inhibitors

A role for cellular inhibitors of apoptosis (IAPs [cIAPs]) in preventing CD95 death has been suspected but not previously explained mechanistically. In this study, we find that the loss of cIAPs leads to a dramatic sensitization to CD95 ligand (CD95L) killing. Surprisingly, this form of cell death can only be blocked by a combination of RIP1 (receptor-interacting protein 1) kinase and caspase inhibitors. Consistently, we detect a large increase in RIP1 levels in the CD95 death-inducing signaling complex (DISC) and in a secondary cytoplasmic complex (complex II) in the presence of IAP antagonists and loss of RIP1-protected cells from CD95L/IAP antagonist–induced death. Cells resistant to CD95L/IAP antagonist treatment could be sensitized by short hairpin RNA–mediated knockdown of cellular FLICE-inhibitory protein (cFLIP). However, only cFLIPL and not cFLIPS interfered with RIP1 recruitment to the DISC and complex II and protected cells from death. These results demonstrate a fundamental role for RIP1 in CD95 signaling and provide support for a physiological role of caspase-independent death receptor–mediated cell death.

scholarly journals TRAF-interacting Protein (TRIP): A Novel Component of the Tumor Necrosis Factor Receptor (TNFR)- and CD30-TRAF Signaling Complexes That Inhibits TRAF2-mediated NF-κB Activation

1997 ◽  
Vol 185 (7) ◽  
pp. 1275-1286 ◽  
Author(s):  
Soo Young Lee ◽  
Sang Yull Lee ◽  
Yongwon Choi
Keyword(s):  
Cell Death ◽  
Tumor Necrosis Factor ◽  
Tumor Necrosis ◽  
Cell Activation ◽  
Tumor Necrosis Factor Receptor ◽  
Interacting Protein ◽  
Signaling Complex ◽  
Wide Range ◽  
Tnfr Superfamily ◽  
Necrosis Factor

Through their interaction with the TNF receptor–associated factor (TRAF) family, members of the tumor necrosis factor receptor (TNFR) superfamily elicit a wide range of biological effects including differentiation, proliferation, activation, or cell death. We have identified and characterized a novel component of the receptor–TRAF signaling complex, designated TRIP (TRAF-interacting protein), which contains a RING finger motif and an extended coiled-coil domain. TRIP associates with the TNFR2 or CD30 signaling complex through its interaction with TRAF proteins. When associated, TRIP inhibits the TRAF2-mediated NF-κB activation that is required for cell activation and also for protection against apoptosis. Thus, TRIP acts as a receptor–proximal regulator that may influence signals responsible for cell activation/proliferation and cell death induced by members of the TNFR superfamily.

scholarly journals K63-linked ubiquitination regulates RIPK1 kinase activity to prevent cell death during embryogenesis and inflammation

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Yong Tang ◽  
Hailin Tu ◽  
Jie Zhang ◽  
Xueqiang Zhao ◽  
Yini Wang ◽  
...  
Keyword(s):  
Cell Death ◽  
Protein Kinase ◽  
Kinase Activity ◽  
Control Cell ◽  
Embryonic Lethality ◽  
Interacting Protein ◽  
Early Embryonic Lethality ◽  
Massive Cell Death ◽  
Massive Cell ◽  
Dependent Signaling Pathway

Abstract Receptor-interacting protein kinase 1 (RIPK1) is a critical regulator of cell death through its kinase activity. However, how its kinase activity is regulated remains poorly understood. Here, we generate Ripk1K376R/K376R knock-in mice in which the Lys(K)63-linked ubiquitination of RIPK1 is impaired. The knock-in mice display an early embryonic lethality due to massive cell death that is resulted from reduced TAK1-mediated suppression on RIPK1 kinase activity and forming more TNFR1 complex II in Ripk1K376R/K376R cells in response to TNFα. Although TNFR1 deficiency delays the lethality, concomitant deletion of RIPK3 and Caspase8 fully prevents embryonic lethality of Ripk1K376R/K376R mice. Notably, Ripk1K376R/- mice are viable but develop severe systemic inflammation that is mainly driven by RIPK3-dependent signaling pathway, indicating that K63-linked ubiquitination on Lys376 residue of RIPK1 also contributes to inflammation process. Together, our study reveals the mechanism by which K63-linked ubiquitination on K376 regulates RIPK1 kinase activity to control cell death programs.

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