scholarly journals Convergent loss of the necroptosis pathway in disparate mammalian lineages shapes virus countermeasures

2021 ◽  
Author(s):  
Ana Agueda Pinto ◽  
Luis Q. Alves ◽  
Fabiana Neves ◽  
Grant McFadden ◽  
Bertram L Jacobs ◽  
...  

Programmed cell death is a vital process in the life cycle of an organism. Necroptosis, an evolutionary restricted form of programmed necrosis, contributes to the innate immune response by killing pathogen-infected cells. This virus-host interaction pathway is organized around two key components: the receptor-interacting protein kinase 3 (RIPK3), which recruits and phosphorylates the mixed lineage kinase-like protein (MLKL), thus inducing cellular plasma membrane rupture and cell death. Critically, the presence of necroptotic inhibitors in viral genomes validates necroptosis as an important host defense mechanism. Here, we show, counterintuitively, that in different mammalian lineages of mammalian, central components of the necroptotic pathway, such as RIPK3 and MLKL genes, are deleted or display inactivating mutations. Frameshifts or premature stop codons are observed in all the studied species of cetaceans and leporids. In carnivores' genomes, the MLKL gene is deleted, while in a small number of species from afrotheria and rodentia premature stop codons are observed in RIPK3 and/or MLKL. Interestingly, we also found a strong correlation between the disruption of necroptosis in leporids and cetaceans and the absence of the C-terminal domain of E3-like homologs (responsible for necroptosis inhibition) in their naturally infecting poxviruses. Overall, our study provides the first comprehensive picture of the molecular evolution of necroptosis in mammals. The loss of necroptosis multiple times during mammalian evolution highlights the importance of gene/pathway loss for species adaptation and suggests that necroptosis is not required for normal mammalian development. Moreover, this study highlights a co-evolutionary relationship between poxviruses and their hosts, emphasizing the role of host adaptation in shaping virus evolution.

2021 ◽  
Vol 12 ◽  
Author(s):  
Ana Águeda-Pinto ◽  
Luís Q. Alves ◽  
Fabiana Neves ◽  
Grant McFadden ◽  
Bertram L. Jacobs ◽  
...  

Programmed cell death is a vital process in the life cycle of organisms. Necroptosis, an evolutionary form of programmed necrosis, contributes to the innate immune response by killing pathogen-infected cells. This virus-host interaction pathway is organized around two components: the receptor-interacting protein kinase 3 (RIPK3), which recruits and phosphorylates the mixed lineage kinase-like protein (MLKL), inducing cellular plasma membrane rupture and cell death. Critically, the presence of necroptotic inhibitors in viral genomes validates necroptosis as an important host defense mechanism. Here, we show, counterintuitively, that in different mammalian lineages, central components of necroptosis, such as RIPK3 and MLKL, are deleted or display inactivating mutations. Frameshifts or premature stop codons are observed in all the studied species of cetaceans and leporids. In carnivores’ genomes, the MLKL gene is deleted, while in a small number of species from afrotheria and rodentia premature stop codons are observed in RIPK3 and/or MLKL. Interestingly, we also found a strong correlation between the disruption of necroptosis in leporids and cetaceans and the absence of the N-terminal domain of E3-like homologs (responsible for necroptosis inhibition) in their naturally infecting poxviruses. Overall, our study provides the first comprehensive picture of the molecular evolution of necroptosis in mammals. The loss of necroptosis multiple times during mammalian evolution highlights the importance of gene/pathway loss for species adaptation and suggests that necroptosis is not required for normal mammalian development. Moreover, this study highlights a co-evolutionary relationship between poxviruses and their hosts, emphasizing the role of host adaptation in shaping virus evolution.


2021 ◽  
Vol 12 ◽  
Author(s):  
Lingling Wang ◽  
Ling Zhou ◽  
Yuhao Zhou ◽  
Lu Liu ◽  
Weiling Jiang ◽  
...  

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.


2020 ◽  
Vol 117 (31) ◽  
pp. 18600-18607 ◽  
Author(s):  
Asen Daskalov ◽  
Patrick S. Mitchell ◽  
Andrew Sandstrom ◽  
Russell E. Vance ◽  
N. Louise Glass

Programmed cell death (PCD) in filamentous fungi prevents cytoplasmic mixing following fusion between conspecific genetically distinct individuals (allorecognition) and serves as a defense mechanism against mycoparasitism, genome exploitation, and deleterious cytoplasmic elements (i.e., senescence plasmids). Recently, we identifiedregulatorof cell death-1(rcd-1), a gene controlling PCD in germinated asexual spores in the filamentous fungusNeurospora crassa.rcd-1alleles are highly polymorphic and fall into two haplogroups inN. crassapopulations. Coexpression of alleles from the two haplogroups,rcd-1–1andrcd-1–2, is necessary and sufficient to trigger a cell death reaction. Here, we investigated the molecular bases ofrcd-1-dependent cell death. Based on in silico analyses, we found that RCD-1 is a remote homolog of the N-terminal pore-forming domain of gasdermin, the executioner protein of a highly inflammatory cell death reaction termed pyroptosis, which plays a key role in mammalian innate immunity. We show that RCD-1 localizes to the cell periphery and that cellular localization of RCD-1 was correlated with conserved positively charged residues on predicted amphipathic α-helices, as shown for murine gasdermin-D. Similar to gasdermin, RCD-1 binds acidic phospholipids in vitro, notably, cardiolipin and phosphatidylserine, and interacts with liposomes containing such lipids. The RCD-1 incompatibility system was reconstituted in human 293T cells, where coexpression of incompatiblercd-1–1/rcd-1–2alleles triggered pyroptotic-like cell death. Oligomers of RCD-1 were associated with the cell death reaction, further supporting the evolutionary relationship between gasdermin andrcd-1. This report documents an ancient transkingdom relationship of cell death execution modules involved in organismal defense.


Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 328
Author(s):  
Tuy An Trinh ◽  
Young Hye Seo ◽  
Sungyoul Choi ◽  
Jun Lee ◽  
Ki Sung Kang

Oxidative stress is one of the main causes of brain cell death in neurological disorders. The use of natural antioxidants to maintain redox homeostasis contributes to alleviating neurodegeneration. Glutamate is an excitatory neurotransmitter that plays a critical role in many brain functions. However, excessive glutamate release induces excitotoxicity and oxidative stress, leading to programmed cell death. Our study aimed to evaluate the effect of osmundacetone (OAC), isolated from Elsholtzia ciliata (Thunb.) Hylander, against glutamate-induced oxidative toxicity in HT22 hippocampal cells. The effect of OAC treatment on excess reactive oxygen species (ROS), intracellular calcium levels, chromatin condensation, apoptosis, and the expression level of oxidative stress-related proteins was evaluated. OAC showed a neuroprotective effect against glutamate toxicity at a concentration of 2 μM. By diminishing the accumulation of ROS, as well as stimulating the expression of heat shock protein 70 (HSP70) and heme oxygenase-1 (HO-1), OAC triggered the self-defense mechanism in neuronal cells. The anti-apoptotic effect of OAC was demonstrated through its inhibition of chromatin condensation, calcium accumulation, and reduction of apoptotic cells. OAC significantly suppressed the phosphorylation of mitogen-activated protein kinases (MAPKs), including c-Jun NH2-terminal kinase (JNK), extracellular signal-regulated kinase (ERK), and p38 kinases. Thus, OAC could be a potential agent for supportive treatment of neurodegenerative diseases.


2020 ◽  
Vol 22 (1) ◽  
pp. 202
Author(s):  
Josephin Glück ◽  
Julia Waizenegger ◽  
Albert Braeuning ◽  
Stefanie Hessel-Pras

Pyrrolizidine alkaloids (PAs) are a group of secondary metabolites produced in various plant species as a defense mechanism against herbivores. PAs consist of a necine base, which is esterified with one or two necine acids. Humans are exposed to PAs by consumption of contaminated food. PA intoxication in humans causes acute and chronic hepatotoxicity. It is considered that enzymatic PA toxification in hepatocytes is structure-dependent. In this study, we aimed to elucidate the induction of PA-induced cell death associated with apoptosis activation. Therefore, 22 structurally different PAs were analyzed concerning the disturbance of cell viability in the metabolically competent human hepatoma cell line HepaRG. The chosen PAs represent the main necine base structures and the different esterification types. Open-chained and cyclic heliotridine- and retronecine-type diesters induced strong cytotoxic effects, while treatment of HepaRG with monoesters did not affect cell viability. For more detailed investigation of apoptosis induction, comprising caspase activation and gene expression analysis, 14 PA representatives were selected. The proapoptotic effects were in line with the potency observed in cell viability studies. In vitro data point towards a strong structure–activity relationship whose effectiveness needs to be investigated in vivo and can then be the basis for a structure-associated risk assessment.


2017 ◽  
Vol 114 (36) ◽  
pp. E7450-E7459 ◽  
Author(s):  
Shuzhen Liu ◽  
Hua Liu ◽  
Andrea Johnston ◽  
Sarah Hanna-Addams ◽  
Eduardo Reynoso ◽  
...  

Mixed-lineage kinase domain-like protein (MLKL) is essential for TNF-α–induced necroptosis. How MLKL promotes cell death is still under debate. Here we report that MLKL forms SDS-resistant, disulfide bond-dependent polymers during necroptosis in both human and mouse cells. MLKL polymers are independent of receptor-interacting protein kinase 1 and 3 (RIPK1/RIPK3) fibers. Large MLKL polymers are more than 2 million Da and are resistant to proteinase K digestion. MLKL polymers are fibers 5 nm in diameter under electron microscopy. Furthermore, the recombinant N-terminal domain of MLKL forms amyloid-like fibers and binds Congo red dye. MLKL mutants that cannot form polymers also fail to induce necroptosis efficiently. Finally, the compound necrosulfonamide conjugates cysteine 86 of human MLKL and blocks MLKL polymer formation and subsequent cell death. These results demonstrate that disulfide bond-dependent, amyloid-like MLKL polymers are necessary and sufficient to induce necroptosis.


Blood ◽  
2012 ◽  
Vol 119 (10) ◽  
pp. 2368-2375 ◽  
Author(s):  
Guilherme B. Fortes ◽  
Leticia S. Alves ◽  
Rosane de Oliveira ◽  
Fabianno F. Dutra ◽  
Danielle Rodrigues ◽  
...  

Abstract Diseases that cause hemolysis or myonecrosis lead to the leakage of large amounts of heme proteins. Free heme has proinflammatory and cytotoxic effects. Heme induces TLR4-dependent production of tumor necrosis factor (TNF), whereas heme cytotoxicity has been attributed to its ability to intercalate into cell membranes and cause oxidative stress. We show that heme caused early macrophage death characterized by the loss of plasma membrane integrity and morphologic features resembling necrosis. Heme-induced cell death required TNFR1 and TLR4/MyD88-dependent TNF production. Addition of TNF to Tlr4−/− or to Myd88−/− macrophages restored heme-induced cell death. The use of necrostatin-1, a selective inhibitor of receptor-interacting protein 1 (RIP1, also known as RIPK1), or cells deficient in Rip1 or Rip3 revealed a critical role for RIP proteins in heme-induced cell death. Serum, antioxidants, iron chelation, or inhibition of c-Jun N-terminal kinase (JNK) ameliorated heme-induced oxidative burst and blocked macrophage cell death. Macrophages from heme oxygenase-1 deficient mice (Hmox1−/−) had increased oxidative stress and were more sensitive to heme. Taken together, these results revealed that heme induces macrophage necrosis through 2 synergistic mechanisms: TLR4/Myd88-dependent expression of TNF and TLR4-independent generation of ROS.


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