scholarly journals Syk facilitates phagosome-lysosome fusion by regulating actin-remodeling in complement-mediated phagocytosis

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Hiroyuki Tabata ◽  
Hiroyuki Morita ◽  
Hiroaki Kaji ◽  
Kaoru Tohyama ◽  
Yumi Tohyama
Keyword(s):  
Candida Albicans ◽  
Tyrosine Kinase ◽  
Host Defense ◽  
Pivotal Role ◽  
Actin Remodeling ◽  
Stabilizing Agent ◽  
Hl60 Cells ◽  
Internalization Process ◽  
Actin Structure

AbstractEffective phagocytosis is crucial for host defense against pathogens. Macrophages entrap pathogens into a phagosome and subsequently acidic lysosomes fuse to the phagosome. Previous studies showed the pivotal role of actin-remodeling mediated by phosphoinositide-related signaling in phagosome formation, but the mechanisms of phagosome-lysosome fusion remain unexplored. Here we show that in complement-mediated phagocytosis, phagosome-lysosome fusion requires the disappearance of F-actin structure surrounding the phagosome and a tyrosine kinase Syk plays a key role in this process. Using macrophage-like differentiated HL60 and Syk-knockout (Syk-KO) HL60 cells, we found that Syk-KO cells showed insufficient phagosome acidification caused by impaired fusion with lysosomes and permitted the survival of Candida albicans in complement-mediated phagocytosis. Phagosome tracking analysis showed that during phagosome internalization process, F-actin surrounding phagosomes disappeared in both parental and Syk-KO cells but this structure was reconstructed immediately only in Syk-KO cells. In addition, F-actin-stabilizing agent induced a similar impairment of phagosome-lysosome fusion. Collectively, Syk-derived signaling facilitates phagosome-lysosome fusion by regulating actin-remodeling.

Syk Plays an Essential Role in Phagosome-Lysosome Fusion By Facilitating Actin-Remodeling in Complement-Mediated Phagocytosis

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 2315-2315
Author(s):  
Yumi Tohyama ◽  
Hiroyuki Tabata ◽  
Kaoru Tohyama
Keyword(s):  
Host Defense ◽  
Bactericidal Activity ◽  
Essential Role ◽  
Conflicts Of Interest ◽  
Flow Cytometric Analysis ◽  
Ph Change ◽  
Fluorescent Intensity ◽  
Actin Remodeling ◽  
Hl60 Cells ◽  
Actin Structure

Complement-mediated phagocytosis plays an essential role in host defense against invading pathogens. Phagocytosis requires a dynamic and coordinated reconstruction of the membrane and the underlying cytoskeleton. Pathogens are entrapped into a phagosome and internalized into the cell. Subsequently, the phagosome fuses with lysosomes to form a phagolysosome with gradual acidification. Previous studies showed the pivotal roles of phosphoinositide-mediated signaling and the synchronous actin-remodeling in phagosome formation, but the mechanisms of phagolysosome generation, namely phagosome-lysosome fusion remain largely unexplored. Here we show that phagosome-lysosome fusion requires the collapse of F-actin structure surrounding phagosomes and a tyrosine kinase, Syk plays a key role in this process. To reveal the mechanisms of phagosome-lysosome fusion particularly focusing on Syk, we performed complement-mediated phagocytosis assay using human leukemic HL60 and Syk-knockout (Syk-KO) HL60 cells established by the CRISPR/Cas9 system. Parental HL60 and Syk-KO HL60 were differentiated into macrophage-like cells and incubated with complement-opsonized Candida albicans(C. albicans) or fluorescence-labeled zymosan particles. Syk-KO cells permitted the survival of C. albicansand their escape from the phagosome.In general, after fusion with lysosomes, the phagosome acquires acidic milieu inside the organelle and enhanced bactericidal activity. To confirm the effects of Syk-KO on phagosome acidification, we used two types of fluorescence-labeled zymosan particles: one was labeled with fluorescein isothiocyanate (FITC) whose fluorescent intensity is reduced under decreased pH condition and the other was labeled with Texas Red whose intensity is conserved independent of pH change. Flow cytometric analysis indicated that Syk-KO cells showed insufficient phagosome acidification. These results suggest that Syk facilitates acidification of phagosomes and results in an enhanced bactericidal activity against pathogens following complement-mediated phagocytosis. Since ourprevious study indicated the participation of Syk in dynamics of actin cytoskeleton, we examined the effect of Syk-KO on the distribution of F-actin around phagosomes. Two hours after phagocytosis, pathogen-containing phagosomes of both parental and Syk-KO HL60 cells were already intracellularly distributed. At that time, F-actin structure around phagosomes of parental HL60 cells was hardly invisible but the phagosomes of Syk-KO cells were circumscribed by dense F-actin structure. An F-actin-stabilizing agent, jasplakinolide induced a similar fusion defect in peripheral blood-derived monocytes as observed in Syk-KO cells. Presence of dense F-actin structure surrounding phagosomes seemed to be responsible for inhibiting phagosome-lysosome fusion. In other words, collapse of F-actin structure surrounding phagosomes may be a critical step of phagolysosome generation. Our results demonstrate that actin-remodeling is essential not only for phagosome formation but also for phagosome-lysosome fusion in complement-mediated phagocytosis and that Syk promotes this process. The present study provides new insights into the mechanism controlling phagocytic progression that leads to host defense against pathogens. Disclosures No relevant conflicts of interest to declare.

Antitumor Genotoxic Agents, Such as Fludarabine*, Doxorubincin or Cis-Platine, Induce Activation of STAT1 in a p53 Protein Dependent Manner.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4384-4384
Author(s):  
Ibtissam Youlyouz-Marfak ◽  
Christophe Le Clorennec ◽  
Imen Najjar ◽  
Fanny Baran-Marszak ◽  
Nathalie Gachard ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
P53 Protein ◽  
Surrogate Marker ◽  
Dependent Manner ◽  
Hl60 Cells ◽  
Over Expression ◽  
Cellular Models ◽  
Genotoxic Agents ◽  
P53 Activation

Abstract Introduction: Chemotherapeutic drug such as Fludarabine*; doxorubicin or cis-platine induce cell cycle arrest and apoptosis via activation of p53. Convergent studies suggest that p53 and STAT1 cooperate in the induction of apoptosis, and that STAT1 favors p53 activation. However, to our knowledge, the role of p53 in the activation of STAT1 is not documented. We present our results suggesting that (i) genotoxic agents are STAT1 inducers, (ii) STAT1 activation depends on the presence of p53 protein, and (iii) this phenomenon is modulated by the tyrosine kinase inhibitor STI571. Materials and Methods: To analyse the role of p53 in STAT1 activation, we have used different cellular models with different p53 status: PRI (p53wt), BL2 (p53wt), BL41 (p53 mutated on Arg248, resulting in the loss of p53 DNA binding activity (p53mut)), Jurkat, HL60 and MEF (the 3 latter being p53 null). The following cDNAs were used for functional studies: p53wt, p53mut, MDM2 and MTBP (MDM2 transforming protein). These cDNAs were cloned either in a pcDNA3 vector or a pRT-1 inducible vector (in the latter, the gene of interest is expressed from a bidirectional doxycycline regulatable promoter allowing simultaneous expression of truncated NGF receptor, used as a surrogate marker of inducibility). Results: Treatment of the different cell lines with the 3 genotoxic drugs Fludarabine*, doxorubicin or cis-platine induced STAT1 activation in p53wt BL2 or PRI cells and in p53mut BL41 cells, but not in Jurkat cells neither in HL60 or MEF cells. Induction of STAT1 was also obtained in presence of the RNA synthesis inhibitor Actinomycin D or in presence of secretion inhibitor Brefeldine A. Over-expression of p53wt or p53mut markedly increased STAT1 activation in PRI cells. This effect was reversed by over-expression of MTBP. Complementation of both HL60 and MEF cells with both p53wt and p53mut cDNA induced constitutive STAT1 activation, an effect that was increased by treatment with doxorubine in transfected HL60 cells. This effect was reversed by over-expression of MDM2 in HL60 cells. Finally, we found that treatment of cells with the inhibitor STI 571 of c-Abl tyrosine kinase, a kinase known to be associated with ATM during p53 activation, decreased STAT1 activation by genotoxic drugs. Conclusion: Our results show that genotoxic agents are inducers of STAT1, that p53 protein but not p53 transcriptional activity is responsible for this STAT1 activation, and suggest a possible involvement the cABL tyrosine kinase.

A pivotal role of cysteine 3 of Lck tyrosine kinase for localization to glycolipid-enriched microdomains and T cell activation

2001 ◽  
Vol 76 (2) ◽  
pp. 133-138 ◽  
Author(s):  
Atsushi Kosugi ◽  
Fumie Hayashi ◽  
Douglas R. Liddicoat ◽  
Koubun Yasuda ◽  
Shin-ichiroh Saitoh ◽  
...  
Keyword(s):  
T Cell ◽  
Tyrosine Kinase ◽  
T Cell Activation ◽  
Cell Activation ◽  
Pivotal Role

scholarly journals Role of Interleukin-18 in Host Defense against Disseminated Candida albicans Infection

2002 ◽  
Vol 70 (6) ◽  
pp. 3284-3286 ◽  
Author(s):  
Rogier J. L. Stuyt ◽  
Mihai G. Netea ◽  
Ineke Verschueren ◽  
Giamila Fantuzzi ◽  
Charles A. Dinarello ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Protective Effect ◽  
Host Defense ◽  
Gamma Interferon ◽  
Interleukin 18 ◽  
Ifn Γ ◽  
Candida Albicans Infection ◽  
Deficient Mice

ABSTRACT In mice injected intravenously with Candida albicans, administration of anti-interleukin-18 (IL-18) antibodies increased the yeast load in the kidneys. There was no effect on the organ load with Candida when gamma interferon (IFN-γ)-deficient mice were treated with anti-IL-18 antibodies, suggesting that the protective effect of IL-18 is mediated through endogenous IFN-γ.

scholarly journals Bruton’s Tyrosine Kinase-Mediated Signaling in Myeloid Cells Is Required for Protective Innate Immunity During Pneumococcal Pneumonia

2021 ◽  
Vol 12 ◽  
Author(s):  
Alexander P. de Porto ◽  
Zhe Liu ◽  
Regina de Beer ◽  
Sandrine Florquin ◽  
Joris J. T. H. Roelofs ◽  
...  
Keyword(s):  
B Cells ◽  
Tyrosine Kinase ◽  
B Cell ◽  
Host Defense ◽  
Pneumococcal Pneumonia ◽  
Myeloid Cells ◽  
Natural Antibody ◽  
Bruton's Tyrosine Kinase

Bruton’s tyrosine kinase (Btk) is a cytoplasmic kinase expressed in B cells and myeloid cells. It is essential for B cell development and natural antibody-mediated host defense against bacteria in humans and mice, but little is known about the role of Btk in innate host defense in vivo. Previous studies have indicated that lack of (natural) antibodies is paramount for impaired host defense against Streptococcus (S.) pneumoniae in patients and mice with a deficiency in functional Btk. In the present study, we re-examined the role of Btk in B cells and myeloid cells during pneumococcal pneumonia and sepsis in mice. The antibacterial defense of Btk-/- mice was severely impaired during pneumococcal pneumosepsis and restoration of natural antibody production in Btk-/- mice by transgenic expression of Btk specifically in B cells did not suffice to protect against infection. Btk-/- mice with reinforced Btk expression in MhcII+ cells, including B cells, dendritic cells and macrophages, showed improved antibacterial defense as compared to Btk-/- mice. Bacterial outgrowth in Lysmcre-Btkfl/Y mice was unaltered despite a reduced capacity of Btk-deficient alveolar macrophages to respond to pneumococci. Mrp8cre-Btkfl/Y mice with a neutrophil specific paucity in Btk expression, however, demonstrated impaired antibacterial defense. Neutrophils of Mrp8cre-Btkfl/Y mice displayed reduced release of granule content after pulmonary installation of lipoteichoic acid, a gram-positive bacterial cell wall component relevant for pneumococci. Moreover, Btk deficient neutrophils showed impaired degranulation and phagocytosis upon incubation with pneumococci ex vivo. Taken together, the results of our study indicate that besides regulating B cell-mediated immunity, Btk is critical for regulation of myeloid cell-mediated, and particularly neutrophil-mediated, innate host defense against S. pneumoniae in vivo.

Role of the macrophage-inducible C-type lectin Mincle in the lung host defense against mycobacterial infections in mice

Pneumologie ◽  
2011 ◽  
Vol 65 (12) ◽  
Author(s):  
F Behler ◽  
K Steinwede ◽  
R Maus ◽  
J Bohling ◽  
UA Maus
Keyword(s):  
Host Defense ◽  
Mycobacterial Infections

A REVIEW ON THE ROLE OF TYROSINE KINASE INHIBITORS AVAILABLE FOR THE MANAGEMENT OF CHRONIC MYELOID LEUKEMIA

2020 ◽  
Vol 7 (2) ◽  
pp. 205-211
Author(s):  
Kaynat Fatima ◽  
Syed Tasleem Raza ◽  
Ale Eba ◽  
Sanchita Srivastava ◽  
Farzana Mahdi
Keyword(s):  
Chronic Myeloid Leukemia ◽  
Tyrosine Kinase ◽  
Protein Kinases ◽  
Tyrosine Kinase Inhibitors ◽  
Myeloid Leukemia ◽  
Kinase Inhibitors ◽  
Line Treatment ◽  
First Line ◽  
First Line Treatment

The function of protein kinases is to transfer a γ-phosphate group from ATP to serine, threonine, or tyrosine residues. Many of these kinases are linked to the initiation and development of human cancer. The recent development of small molecule kinase inhibitors for the treatment of different types of cancer in clinical therapy has proven successful. Significantly, after the G-protein-coupled receptors, protein kinases are the second most active category of drug targets. Imatinib mesylate was the first tyrosine kinase inhibitor (TKI), approved for chronic myeloid leukemia (CML) treatment. Imatinib induces appropriate responses in ~60% of patients; with ~20% discontinuing therapy due to sensitivity, and ~20% developing drug resistance. The introduction of newer TKIs such as, nilotinib, dasatinib, bosutinib, and ponatinib has provided patients with multiple options. Such agents are more active, have specific profiles of side effects and are more likely to reach the necessary milestones. First-line treatment decisions must be focused on CML risk, patient preferences and comorbidities. Given the excellent result, half of the patients eventually fail to seek first-line treatment (due to discomfort or resistance), with many of them needing a third or even further therapy lines. In the present review, we will address the role of tyrosine kinase inhibitors in therapy for chronic myeloid leukemia.

Sign in / Sign up

Export Citation Format

Share Document