Pathogen-Associated Molecular Patterns Are Growth and Survival Factors for Human Myeloma Cells through Toll-Like Receptors.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3403-3403
Author(s):  
Gaetan Jego ◽  
Catherine Pellat-Deceunynck ◽  
Catherine David ◽  
Bataille Regis
Keyword(s):  
Plasma Cells ◽  
Viral Infections ◽  
Innate Immune ◽  
Blocking Antibody ◽  
Autocrine Loop ◽  
Growth And Survival ◽  
The One ◽  
Induced Apoptosis ◽  
Molecular Patterns ◽  
Receptor Family

Abstract Multiple Myeloma (MM) patients are strongly sensitive to bacterial, fungal and viral infections. Furthermore, MM is often newly diagnosed in the context of such infections. Given those recurrent infections remain a major cause of death of MM patients; we surmised that MM plasma-cells could be activated by microorganisms, therefore contributing to the initiation and progression of the disease. Microorganisms share highly conserved structures called pathogen-associated molecular patterns. They are recognized by a family of receptors that act as sensor for the innate immune system and are called the Toll-like receptor family (TLRs). We first measured the expression of the 10 known human TLRs on 16 human MM plasma-cells lines (HMCLs) and freshly purified Plasma-cells from 13 patients. The expression pattern is heterogeneous among HMCLs and does not correlate with the one of B cells. Indeed TLR-3, 4, and 8 are aberrantly expressed. On the contrary, the expression of TLR-2 and 10 is lost on most of the HMCLs. TLR-1, 7 and 9 are the most frequently expressed (15+/16, 12+/16 and 11+/16 respectively). Primary MM plasma-cells also express TLR-7 (9+/13) and TLR-9 (8+/13). Accordingly to this expression profile, culture with TLR-7 ligand (loxoribine) or TLR-9 ligand (hypomethylated DNA from bacteria) increased 1,7 to 6 times (mean 3 ± 1,4 n= 8) the proliferation of IL-6-dependent and independent HMCLs. Furthermore, we observed a resistance to serum-deprivation as well as to dexamethasone-induced apoptosis. Those effects were IL-6-mediated in IL-6-dependent HMCLs since a blocking antibody to IL-6 neutralized the growth and survival induced by TLR triggering. In conclusion, human MM Plasma-cells express a broad range of TLRs and the triggering of TLR-7 and 9 induces tumor cell growth and prevent chemotherapy-induced apoptosis. These effects are mediated by the induction of an autocrine loop of growth factors as IL-6, and others currently under identification in the case of IL-6 independent HMCLs. Thus, MM plasma-cells take advantage of infections to expand and escape to usual therapies.

CD27-Mediated Apoptosis Is Dependent on Siva-Induced Caspase Activation in Human Multiple Myeloma.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3398-3398 ◽  
Author(s):  
Yu-Tzu Tai ◽  
Xian-Feng Li ◽  
Rory Coffey ◽  
Iris Breitkreutz ◽  
Laurence Catley ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Cell Death ◽  
Cell Growth ◽  
Growth Inhibition ◽  
Plasma Cells ◽  
Death Domain ◽  
Caspase Activation ◽  
Growth And Survival ◽  
Induced Apoptosis ◽  
Cell Growth And Survival

Abstract CD27, a member of tumor necrosis factor receptor superfamily that lacks a death domain in its cytoplasmic region, and its interaction with its ligand, CD70, is crucial for differentiation into plasma cells. In malignant B cells, aberrant expression and reverse signaling of CD70 might contribute to disease progression. Recent studies showed that CD27 is heterogeneously expressed on multiple myeloma (MM) plasma cells and the expression is reduced with the progression of MM. However, a possible role for the loss of CD27-CD70 interaction in myelomagenesis was never defined. In this study, we identify functional significance of CD27-CD70 interaction in 4 CD27-expressing MM lines and define mechanisms regulating CD27-mediated MM cell death. Using RT-PCR and flow cytometric analysis, we first found that all of MM lines highly express CD70 (n=10) and 4 MM lines 12BM, 12PE, 28BM, 28PE express CD27 on the cell surface. We next evaluated the effect of CD27 ligation, by CD70-transfected NIH3T3 cells (CD70 transfectant), on [3H] thymidine incorporation by CD27-expressing MM lines. CD27 ligation by CD70 transfectants inhibited DNA synthesis in these 4 CD27-expressing MM lines, but not the control transfectants. Conversely, a blocking anti-CD70 mAb blocked CD27-mediated growth inhibition in a dose-dependent manner, indicating induced growth inhibition specific triggered by CD27-CD70 interaction. Using MTT assay, CD27 ligation by CD70 transfectant also inhibited MM cell survival. IL-6 (20 ng/ml) could overcome the inhibitory effect triggered by CD27 ligation on MM cell growth and survival. In addition, CD27 ligation further enhanced Dex-induced MM cell death. Importantly, CD27-mediated MM cell death was also observed in 2 CD27-expressing patient MM cells. Since Siva is a death domain-containing proapoptotic protein identified as an intracellular ligand of CD27, we investigated its role in CD27-mediated apoptosis in MM cells. Overexpression of Siva by transducing adenovirus-expressing Siva (Ad-Siva-GFP) in 12BM MM line is sufficient to induce cell death whereas control adenovirus (Ad-GFP) transduction did not alter 12BM cell growth and survival. CD27 ligation by CD70 transfectants on Siva-overexpressing 12BM cells further enhanced Siva-induced apoptosis, as evidenced by increased subG0 fraction in cell cycle analysis. Thus, the apoptosis triggered by Siva overexpression was related to the CD27-mediated apoptotic pathway. We further determined caspase involvement in the Siva-induced apoptosis in the absence and presence of CD70 transfectants. Caspase 8 and caspase 9 activities were detected 24h following Ad-Siva-GFP transduction in 12BM cells, whereas caspas-3 activity was detected 48h after transduction. Coculture of Ad-Siva-GFP-transduced 12BM cells with CD70 transfectant further enhanced caspase activities. Therefore, overexpression of Siva is sufficient to induce apoptosis and CD27-mediated apoptosis is mediated by Siva-dependent caspase activation in MM. Furthermore, these results suggest that lack of CD27 may lead to evasion of apoptosis in human MM.

scholarly journals Cellular Responses to Cytosolic Double-stranded RNA–-The Role of the Inflammasome

2014 ◽  
Vol 6 ◽  
pp. III.S17839 ◽  
Author(s):  
Adi Idris
Keyword(s):  
Innate Immune System ◽  
Viral Infections ◽  
Cellular Responses ◽  
Specific Pattern ◽  
Innate Immune ◽  
Host Cells ◽  
Virus Infected Cell ◽  
Double Stranded Rna ◽  
Molecular Patterns

Sensing the presence of a pathogen is an evolutionarily ancient trait, especially for cells of the innate immune system. The innate immune response against pathogens, such as viruses, begins with recognition of pathogen-associated molecular patterns (PAMPs) by specific pattern-recognition receptors (PRRs). Cytosolic double-stranded RNA (dsRNA) is emerging as a critical PAMP in the detection of viral infections. This recognition results in the production of antiviral and proinflammatory cytokines and, often, the death of the virus-infected cell. This review focuses on the current developments in the role of inflammasomes in response to the presence of cytosolic dsRNA in host cells. More importantly, it highlights important unanswered questions that if addressed will help us better understand the ways in which host cells respond to viral infection, in particular RNA viruses.

scholarly journals Emerging Role of PYHIN Proteins as Antiviral Restriction Factors

Viruses ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 1464
Author(s):  
Matteo Bosso ◽  
Frank Kirchhoff
Keyword(s):  
Viral Infections ◽  
Specific Pattern ◽  
Immune Defense ◽  
Innate Immune ◽  
Cellular Proteins ◽  
Restriction Factors ◽  
First Line ◽  
Viral Pathogens ◽  
Molecular Patterns

Innate immune sensors and restriction factors are cellular proteins that synergize to build an effective first line of defense against viral infections. Innate sensors are usually constitutively expressed and capable of detecting pathogen-associated molecular patterns (PAMPs) via specific pattern recognition receptors (PRRs) to stimulate the immune response. Restriction factors are frequently upregulated by interferons (IFNs) and may inhibit viral pathogens at essentially any stage of their replication cycle. Members of the Pyrin and hematopoietic interferon-inducible nuclear (HIN) domain (PYHIN) family have initially been recognized as important sensors of foreign nucleic acids and activators of the inflammasome and the IFN response. Accumulating evidence shows, however, that at least three of the four members of the human PYHIN family restrict viral pathogens independently of viral sensing and innate immune activation. In this review, we provide an overview on the role of human PYHIN proteins in the innate antiviral immune defense and on viral countermeasures.

scholarly journals Role of Toll-Like Receptors in Activation of Porcine Alveolar Macrophages by Porcine Reproductive and Respiratory Syndrome Virus

2009 ◽  
Vol 16 (3) ◽  
pp. 360-365 ◽  
Author(s):  
Laura C. Miller ◽  
Kelly M. Lager ◽  
Marcus E. Kehrli
Keyword(s):  
Alveolar Macrophages ◽  
Viral Infections ◽  
Rna Virus ◽  
Innate Immune ◽  
Respiratory Syndrome Virus ◽  
Double Stranded Rna ◽  
Tlr4 Activation ◽  
Molecular Patterns ◽  
Rapid Activation

ABSTRACT Control of virus replication initially depends on rapid activation of the innate immune response. Toll-like receptor (TLR) ligands are potent inducers of innate immunity against viral infections. Porcine reproductive and respiratory syndrome virus (PRRSV), a positive-sense RNA virus, initiates infection in porcine alveolar macrophages (PAMs), elicits weak immune responses, and establishes a persistent infection. To understand the role of single-stranded RNA and double-stranded RNA (dsRNA) intermediates in eliciting host immunity, we sought to determine if TLRs, particularly those that respond to viral molecular patterns, are involved in PRRSV infection. Activation of TLR3 in PAMs with dsRNA increased gene expression for alpha interferon and suppressed PRRSV infectivity. In contrast, TLR4 activation by the treatment of PAMs with lipopolysaccharide did not influence PRRSV infectivity.

scholarly journals The L1-dependant and Pol III transcribed Alu retrotransposon, from its discovery to innate immunity

2021 ◽  
Vol 48 (3) ◽  
pp. 2775-2789
Author(s):  
Ludwig Stenz
Keyword(s):  
Human Genome ◽  
Viral Infections ◽  
De Novo ◽  
Current Knowledge ◽  
Innate Immune ◽  
De Novo Mutation ◽  
Neuronal Diversity ◽  
Alu Sequences ◽  
Pol Iii ◽  
The Brain

AbstractThe 300 bp dimeric repeats digestible by AluI were discovered in 1979. Since then, Alu were involved in the most fundamental epigenetic mechanisms, namely reprogramming, pluripotency, imprinting and mosaicism. These Alu encode a family of retrotransposons transcribed by the RNA Pol III machinery, notably when the cytosines that constitute their sequences are de-methylated. Then, Alu hijack the functions of ORF2 encoded by another transposons named L1 during reverse transcription and integration into new sites. That mechanism functions as a complex genetic parasite able to copy-paste Alu sequences. Doing that, Alu have modified even the size of the human genome, as well as of other primate genomes, during 65 million years of co-evolution. Actually, one germline retro-transposition still occurs each 20 births. Thus, Alu continue to modify our human genome nowadays and were implicated in de novo mutation causing diseases including deletions, duplications and rearrangements. Most recently, retrotransposons were found to trigger neuronal diversity by inducing mosaicism in the brain. Finally, boosted during viral infections, Alu clearly interact with the innate immune system. The purpose of that review is to give a condensed overview of all these major findings that concern the fascinating physiology of Alu from their discovery up to the current knowledge.

scholarly journals NOD-Like Receptors: Guards of Cellular Homeostasis Perturbation during Infection

2021 ◽  
Vol 22 (13) ◽  
pp. 6714
Author(s):  
Gang Pei ◽  
Anca Dorhoi
Keyword(s):  
Immune System ◽  
Innate Immune System ◽  
Current Knowledge ◽  
Protein Translation ◽  
Innate Immune ◽  
Cellular Homeostasis ◽  
Translation Block ◽  
Cytoskeleton Disruption ◽  
Molecular Patterns ◽  
Fine Tune

The innate immune system relies on families of pattern recognition receptors (PRRs) that detect distinct conserved molecular motifs from microbes to initiate antimicrobial responses. Activation of PRRs triggers a series of signaling cascades, leading to the release of pro-inflammatory cytokines, chemokines and antimicrobials, thereby contributing to the early host defense against microbes and regulating adaptive immunity. Additionally, PRRs can detect perturbation of cellular homeostasis caused by pathogens and fine-tune the immune responses. Among PRRs, nucleotide binding oligomerization domain (NOD)-like receptors (NLRs) have attracted particular interest in the context of cellular stress-induced inflammation during infection. Recently, mechanistic insights into the monitoring of cellular homeostasis perturbation by NLRs have been provided. We summarize the current knowledge about the disruption of cellular homeostasis by pathogens and focus on NLRs as innate immune sensors for its detection. We highlight the mechanisms employed by various pathogens to elicit cytoskeleton disruption, organelle stress as well as protein translation block, point out exemplary NLRs that guard cellular homeostasis during infection and introduce the concept of stress-associated molecular patterns (SAMPs). We postulate that integration of information about microbial patterns, danger signals, and SAMPs enables the innate immune system with adequate plasticity and precision in elaborating responses to microbes of variable virulence.

scholarly journals Role of the Inflammasome, IL-1β, and IL-18 in Bacterial Infections

2011 ◽  
Vol 11 ◽  
pp. 2037-2050 ◽  
Author(s):  
Manoranjan Sahoo ◽  
Ivonne Ceballos-Olvera ◽  
Laura del Barrio ◽  
Fabio Re
Keyword(s):  
Bacterial Infections ◽  
Innate Immune ◽  
Host Responses ◽  
Inflammasome Activation ◽  
Different Types ◽  
Molecular Aspects ◽  
Immune Pathway ◽  
Innate Immune Pathway ◽  
Receptor Family

The inflammasome is an important innate immune pathway that regulates at least two host responses protective against infections: (1) secretion of the proinflammatory cytokines IL-1βand IL-18 and (2) induction of pyroptosis, a form of cell death. Inflammasomes, of which different types have been identified, are multiprotein complexes containing pattern recognition receptors belonging to the Nod-like receptor family or the PYHIN family and the protease caspase-1. The molecular aspects involved in the activation of different inflammasomes by various pathogens are being rapidly elucidated, and their role during infections is being characterized. Production of IL-1βand IL-18 and induction of pyroptosis of the infected cell have been shown to be protective against many infectious agents. Here, we review the recent literature concerning inflammasome activation in the context of bacterial infections and identify important questions to be answered in the future.

scholarly journals Role of Aiolos and Ikaros in the Antitumor and Immunomodulatory Activity of IMiDs in Multiple Myeloma: Better to Lose Than to Find Them

2021 ◽  
Vol 22 (3) ◽  
pp. 1103
Author(s):  
Marco Cippitelli ◽  
Helena Stabile ◽  
Andrea Kosta ◽  
Sara Petillo ◽  
Angela Gismondi ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Plasma Cells ◽  
Immunomodulatory Activity ◽  
Cancer Cell Growth ◽  
Cytotoxic Effects ◽  
Growth And Survival ◽  
Therapeutic Implications ◽  
Development And Differentiation ◽  
Innate Lymphocytes

The Ikaros zing-finger family transcription factors (IKZF TFs) are important regulators of lymphocyte development and differentiation and are also highly expressed in B cell malignancies, including Multiple Myeloma (MM), where they are required for cancer cell growth and survival. Moreover, IKZF TFs negatively control the functional properties of many immune cells. Thus, the targeting of these proteins has relevant therapeutic implications in cancer. Indeed, accumulating evidence demonstrated that downregulation of Ikaros and Aiolos, two members of the IKZF family, in malignant plasma cells as well as in adaptative and innate lymphocytes, is key for the anti-myeloma activity of Immunomodulatory drugs (IMiDs). This review is focused on IKZF TF-related pathways in MM. In particular, we will address how the depletion of IKZF TFs exerts cytotoxic effects on MM cells, by reducing their survival and proliferation, and concomitantly potentiates the antitumor immune response, thus contributing to therapeutic efficacy of IMiDs, a cornerstone in the treatment of this neoplasia.

scholarly journals Cell Death in Coronavirus Infections: Uncovering Its Role during COVID-19

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1585
Author(s):  
Annamaria Paolini ◽  
Rebecca Borella ◽  
Sara De Biasi ◽  
Anita Neroni ◽  
Marco Mattioli ◽  
...  
Keyword(s):  
Cell Death ◽  
Immune Cells ◽  
Viral Infections ◽  
Virus Entry ◽  
Therapeutic Strategies ◽  
The Other ◽  
Cytokine Storm ◽  
Cytokines And Chemokines ◽  
Cell Death Mechanisms ◽  
The One

Cell death mechanisms are crucial to maintain an appropriate environment for the functionality of healthy cells. However, during viral infections, dysregulation of these processes can be present and can participate in the pathogenetic mechanisms of the disease. In this review, we describe some features of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and some immunopathogenic mechanisms characterizing the present coronavirus disease (COVID-19). Lymphopenia and monocytopenia are important contributors to COVID-19 immunopathogenesis. The fine mechanisms underlying these phenomena are still unknown, and several hypotheses have been raised, some of which assign a role to cell death as far as the reduction of specific types of immune cells is concerned. Thus, we discuss three major pathways such as apoptosis, necroptosis, and pyroptosis, and suggest that all of them likely occur simultaneously in COVID-19 patients. We describe that SARS-CoV-2 can have both a direct and an indirect role in inducing cell death. Indeed, on the one hand, cell death can be caused by the virus entry into cells, on the other, the excessive concentration of cytokines and chemokines, a process that is known as a COVID-19-related cytokine storm, exerts deleterious effects on circulating immune cells. However, the overall knowledge of these mechanisms is still scarce and further studies are needed to delineate new therapeutic strategies.

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