Emerging Roles for RIPK1 and RIPK3 in Pathogen-Induced Cell Death and Host Immunity

2015 ◽  
pp. 37-75
Author(s):  
Danish Saleh ◽  
Alexei Degterev
Keyword(s):  
Cell Death ◽  
Host Immunity

scholarly journals The barley powdery mildew effectors CSEP0139 and CSEP0182 suppress cell death and promote B. graminis fungal virulence in plants

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Xue Li ◽  
Cong Jin ◽  
Hongbo Yuan ◽  
Wanting Huang ◽  
Fang Liu ◽  
...  
Keyword(s):  
Cell Death ◽  
Powdery Mildew ◽  
Host Plants ◽  
Host Immunity ◽  
Effector Proteins ◽  
Fungal Virulence ◽  
Cell Death Pathways ◽  
Barley Powdery Mildew ◽  
Powdery Mildew Fungi ◽  
Transient Overexpression

AbstractThe powdery mildew fungi secrete numerous Candidate Secreted Effector Proteins (CSEPs) to manipulate host immunity during infection of host plants. However, the function of most of these CSEPs in cell death suppression has not yet been established. Here, we identified several CSEPs from Blumeria graminis f. sp. hordei (Bgh) that have the potential to suppress BAX- and NtMEK2DD-triggered cell death in Nicotiana benthamiana. We further characterized two effector candidates, CSEP0139 and CSEP0182, from family six and thirty-two, respectively. CSEP0139 and CSEP0182 contain a functional signal peptide and are likely secreted effectors. Expression of either CSEP0139 or CSEP0182 suppressed cell death triggered by BAX and NtMEK2DD but not by the AVRa13/MLA13 pair in N. benthamiana. Transient overexpression of CSEP0139 or CSEP0182 also inhibited BAX-induced cell death and collapse of cytoplasm in barley cells. Furthermore, overexpression of either CSEPs significantly increased Bgh haustorial formation in barley, whereas host-induced gene silencing (HIGS) of the CSEP genes reduced haustorial formation, suggesting both CSEPs promote Bgh virulence in barley. In addition, expression of CSEP0139 and CSEP0182 reduced size of the lesions caused by the necrotrophic Botrytis cinerea in N. benthamiana. Our findings suggest that CSEP0139 and CSEP0182 may target cell death components in plants to promote fungal virulence, which extends the current understanding of the functions of Bgh CSEPs and provides an opportunity for further investigation of fungal virulence in relation to cell death pathways in host plants.

Helminth-induced apoptosis: a silent strategy for immunosuppression

Parasitology ◽  
2017 ◽  
Vol 144 (13) ◽  
pp. 1663-1676 ◽  
Author(s):  
AMIN ZAKERI
Keyword(s):  
Cell Death ◽  
Immune Cells ◽  
Immune Cell ◽  
Host Immunity ◽  
Microbial Infections ◽  
Successful Group ◽  
Intracellular Process ◽  
Immunoregulatory Cells ◽  
Induced Apoptosis ◽  
Apoptotic Effects

SUMMARYDuring microbial infections, both innate and adaptive immunity are activated. Viruses and bacteria usually induce an acute inflammation in the first setting of infection, which helps the eliciting an effective immune response. In contrast, macroparasites such as helminths are a highly successful group of invaders known to be capable of maintaining a chronic infestation with the minimum instigation. Undoubtedly, generating such an immunoregulatory environment requires the exploitation of various immunosuppressive mechanisms to debilitate host immunity supporting their survival and replication. Several mechanisms have been recognized whereby helminths prolong their infections including an increase of immunoregulatory cells, inhibition of Th1 or Th2 responses, targeting pattern recognition receptors (PRRs) and lowering the immune cells quantity via induction of apoptosis. Apoptosis is a programmed intracellular process involving a series of consecutive downstream signalling event evolved to cell death. It plays a pivotal role in several immunological reactions in particular deletion of autoreactive immune cells. Helminth-triggered apoptosis in immune cells exhausts host immunity, which paves the way for generating a permissive environment and chronic infection. This review provides a compilation of recent investigations discussing the apoptotic mechanisms exploited by different worms and the immunological consequences of immune cell death. Finally, the anti-cancer effects of some worm-derived molecules due to their apoptotic effects are discussed, highlighting as potentially druggable candidates to combat cancer.

DNA nick end labeling: a reliable marker for apoptosis?

1995 ◽  
Vol 53 ◽  
pp. 962-963
Author(s):  
Anne F. Bushnell ◽  
Sarah Webster ◽  
Lynn S. Perlmutter
Keyword(s):  
Cell Death ◽  
Cultured Cells ◽  
Apoptotic Cell ◽  
Morphological Characteristics ◽  
Detection Methods ◽  
Tissue Preparation ◽  
Preparation Methods ◽  
Dna Laddering ◽  
Disease States ◽  
Reliable Marker

Apoptosis, or programmed cell death, is an important mechanism in development and in diverse disease states. The morphological characteristics of apoptosis were first identified using the electron microscope. Since then, DNA laddering on agarose gels was found to correlate well with apoptotic cell death in cultured cells of dissimilar origins. Recently numerous DNA nick end labeling methods have been developed in an attempt to visualize, at the light microscopic level, the apoptotic cells responsible for DNA laddering.The present studies were designed to compare various tissue processing techniques and staining methods to assess the occurrence of apoptosis in post mortem tissue from Alzheimer's diseased (AD) and control human brains by DNA nick end labeling methods. Three tissue preparation methods and two commercial DNA nick end labeling kits were evaluated: the Apoptag kit from Oncor and the Biotin-21 dUTP 3' end labeling kit from Clontech. The detection methods of the two kits differed in that the Oncor kit used digoxigenin dUTP and anti-digoxigenin-peroxidase and the Clontech used biotinylated dUTP and avidinperoxidase. Both used 3-3' diaminobenzidine (DAB) for final color development.

Paracrystalline Aggregates of Psoriatic Keratin and Their Relation to Normal Keratin Structure

1985 ◽  
Vol 43 ◽  
pp. 680-681
Author(s):  
S. Trachtenberg ◽  
P.M. Steinert ◽  
B.L. Trus ◽  
A.C. Steven
Keyword(s):  
Cell Death ◽  
Stratum Corneum ◽  
Intermediate Filament ◽  
Skin Disease ◽  
Amorphous Matrix ◽  
Terminal Differentiation ◽  
Proteolytic Degradation ◽  
Horny Layer ◽  
Chronic Skin ◽  
Chronic Skin Disease

During terminal differentiation of vertebrate epidermis, certain specific keratin intermediate filament (KIF) proteins are produced. Keratinization of the epidermis involves cell death and disruption of the cytoplasm, leaving a network of KIF embedded in an amorphous matrix which forms the outer horny layer known as the stratum corneum. Eventually these cells are shed (desquamation). Normally, the processes of differentiation, keratinization, and desquamation are regulated in an orderly manner. In psoriasis, a chronic skin disease, a hyperkeratotic stratum corneum is produced, resulting in abnormal desquamation of unusually large scales. In this disease, the normal KIF proteins are diminished in amount or absent, and other proteins more typical of proliferative epidermal cells are present. There is also evidence of proteolytic degradation of the KIF.

The early development of antenna and antennal sensilla in the noctuid moth, Agrotis segetum (Insecta: Lepidoptera)

1990 ◽  
Vol 48 (3) ◽  
pp. 502-503
Author(s):  
Eric Hallberg ◽  
Lina Hansén
Keyword(s):  
Cell Death ◽  
Stem Cell ◽  
Early Development ◽  
Larval Stage ◽  
Pupal Stage ◽  
Agrotis Segetum ◽  
Antennal Sensilla ◽  
Noctuid Moth ◽  
Standard Procedures

The antennal rudiments in lepidopterous insects are present as disks during the larval stage. The tubular double-walled antennal disk is present beneath the larval antenna, and its inner layer gives rise to the adult antenna during the pupal stage. The sensilla develop from a cluster of cells that are derived from one stem cell, which gives rise to both sensory and enveloping cells. During the morphogenesis of the sensillum these cells undergo major transformations, including cell death. In the moth Agrotis segetum the pupal stage lasts about 14 days (temperature, 25°C). The antennae, clearly seen from the exterior, were dissected and fixed according to standard procedures (3 % glutaraldehyde in 0.15 M cacaodylate buffer, followed by 1 % osmiumtetroxide in the same buffer). Pupae from day 1 to day 8, of both sexes were studied.

vitreal cells and specialized phagocytes in the chick embryo retina: A TEM and SEM study

1990 ◽  
Vol 48 (3) ◽  
pp. 330-331
Author(s):  
M.A. Cuadros ◽  
M.J. Martinez-Guerrero ◽  
A. Rios
Keyword(s):  
Cell Death ◽  
Plasma Membrane ◽  
Acid Phosphatase ◽  
Chick Embryo ◽  
Basement Membrane ◽  
Sem Images ◽  
Intimate Contact ◽  
Cellular Processes ◽  
Sem Study ◽  
Free Cells

In the chick embryo retina (days 3-4 of incubation), coinciding with an increase in cell death, specialized phagocytes characterized by intense acid phosphatase activity have been described. In these preparations, all free cells in the vitreal humor (vitreal cells) were strongly labeled. Conventional TEM and SEM techniques were used to characterize them and attempt to determine their relationship with retinal phagocytes.Two types of vitreal cells were distinguished. The first are located at some distance from the basement membrane of the neuroepithelium, and are rounded, with numerous vacuoles and thin cytoplasmic prolongations. Images of exo- and or endocytosis were frequent; the cells showed a well-developed Golgi apparatus (Fig. 1) In SEM images, the cells was covered with short cellular processes (Fig. 3). Cells lying parallel to or alongside the basement membrane are elongated. The plasma membrane is frequently in intimate contact with the basement membrane. These cells have generally a large cytoplasmic expansion (Fig. 5).

Signal-regulated oxidation of proteins via MICAL

2020 ◽  
Vol 48 (2) ◽  
pp. 613-620
Author(s):  
Clara Ortegón Salas ◽  
Katharina Schneider ◽  
Christopher Horst Lillig ◽  
Manuela Gellert
Keyword(s):  
Signal Transduction ◽  
Hydrogen Peroxide ◽  
Cell Death ◽  
Redox Regulation ◽  
Signal Transduction Pathways ◽  
Cellular Functions ◽  
Intracellular Signals ◽  
Amino Acid Side Chains ◽  
Specific Receptors ◽  
Sulfur Containing

Processing of and responding to various signals is an essential cellular function that influences survival, homeostasis, development, and cell death. Extra- or intracellular signals are perceived via specific receptors and transduced in a particular signalling pathway that results in a precise response. Reversible post-translational redox modifications of cysteinyl and methionyl residues have been characterised in countless signal transduction pathways. Due to the low reactivity of most sulfur-containing amino acid side chains with hydrogen peroxide, for instance, and also to ensure specificity, redox signalling requires catalysis, just like phosphorylation signalling requires kinases and phosphatases. While reducing enzymes of both cysteinyl- and methionyl-derivates have been characterised in great detail before, the discovery and characterisation of MICAL proteins evinced the first examples of specific oxidases in signal transduction. This article provides an overview of the functions of MICAL proteins in the redox regulation of cellular functions.

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