Chlamydia pneumoniae infection of microglial cells in vitro: a model of microbial infection for neurological disease

2006 ◽  
Vol 55 (7) ◽  
pp. 947-952 ◽  
Author(s):  
Hideaki Ikejima ◽  
Herman Friedman ◽  
Yoshimasa Yamamoto
Keyword(s):  
Neurological Disease ◽  
Chlamydia Pneumoniae ◽  
Inflammatory Diseases ◽  
Microglial Cells ◽  
Infection Model ◽  
Microbial Infection ◽  
Microglial Cell Line ◽  
The Central Nervous System ◽  
Metalloproteinase 9

Chlamydia pneumoniae is the aetiological cause of a wide variety of chronic inflammatory diseases and may be associated with neurological disease. Microbiological and immunological aspects of the interaction between C. pneumoniae and the central nervous system (CNS) are not well understood because of the lack of a suitable infection model for neuronal studies. In the present study, an in vitro C. pneumoniae infection model was developed in the established microglial cell line EOC 20. Infection of the cells resulted in obvious induction of proinflammatory cytokines. The infection also selectively induced matrix metalloproteinase-9 (MMP-9) but not MMP-2. Moreover, beta interferon, which is known to modulate CNS disease, inhibited induction of MMP-9 following C. pneumoniae infection. These results support the view that C. pneumoniae infection may be associated with marked alteration of the ability of microglial cells to enhance cytokine production as well as induction of an MMP.

scholarly journals Chlamydia pneumoniae Resists Antibiotics in Lymphocytes

2003 ◽  
Vol 47 (6) ◽  
pp. 1972-1975 ◽  
Author(s):  
Hiroyuki Yamaguchi ◽  
Herman Friedman ◽  
Mayumi Yamamoto ◽  
Keigo Yasuda ◽  
Yoshimasa Yamamoto
Keyword(s):  
Epithelial Cells ◽  
Bacterial Growth ◽  
Chlamydia Pneumoniae ◽  
Inflammatory Diseases ◽  
Lymphoid Cells ◽  
Infection Model ◽  
Chronic Inflammatory Diseases

ABSTRACT Chlamydia pneumoniae infection of lymphocytes in blood has been well documented, and it is apparent that control of this pathogen in these cells may be critical in the development of chronic inflammatory diseases associated with infection by this bacterium. The activity of antibiotics against C. pneumoniae in lymphocytes was assessed in this study by utilizing an in vitro infection model with lymphoid cells. The results obtained indicated that although all of the antibiotics tested showed remarkable activity against bacterial growth in epithelial cells, C. pneumoniae in lymphocytes was less susceptible to antibiotics than was bacterial growth in epithelial cells, which are widely used for the evaluation of anti-C. pneumoniae antibiotics.

scholarly journals Could Chlamydia Pneumoniae Be Considered an Infectious Risk Factor for Inflammatory Diseases Such as Atherosclerosis ?

2005 ◽  
Vol 3 (3) ◽  
pp. 109-112
Author(s):  
R. Sessa ◽  
M. Di Pietro ◽  
G. Schiavoni ◽  
I. Santino ◽  
M. Del Piano
Keyword(s):  
Risk Factor ◽  
Chlamydia Pneumoniae ◽  
Direct Detection ◽  
Inflammatory Diseases ◽  
Cell Types ◽  
Chronic Inflammatory Disease ◽  
Upper Respiratory Tract ◽  
Infectious Risk ◽  
Tract Infections

Chlamydia pneumoniae, a Gram-negative intracellular obligate bacteria, is recognised as a common cause of upper respiratory tract infections, and accounts for ∼10% of community-acquired pneumonia. In recent years, chronic and persistent infection with C. pneumoniae has been implicated in the pathogenesis of atherosclerosis. Atherosclerosis is regarded as a chronic inflammatory disease that results from complex interactions between a variety of cell types such as endothelial cells, vascular smooth muscle cells, monocytes/macrophages and inflammatory mediators. Involvement of C. pneumoniae in the pathogenesis of atherosclerosis has been supported by findings from seroepidemiologic studies, direct detection of chlamydial DNA, experimental animal and in vitro studies, and antibiotic intervention trials. The spectrum of cell biological, animal, and human clinical data suggests that C. pneumoniae may be considered an infectious risk factor for atherosclerosis but further studies are needed to clarify the etiopathogenetic role of C. pneumoniae in atherosclerotic vessel walls.

scholarly journals PDCD4–MAPK–NF-κB Positive Loop Simultaneously Promotes Microglia Activation and Neuron Apoptosis During Neuroinflammation

2021 ◽  
Author(s):  
Quan Chen ◽  
Hongjian Lu ◽  
Chengwei Duan ◽  
Xiangyang Zhu ◽  
Yi Zhang ◽  
...  
Keyword(s):  
Nuclear Translocation ◽  
Inflammatory Diseases ◽  
Damage Model ◽  
Pdcd4 Expression ◽  
Proapoptotic Protein ◽  
Inflammatory Activation ◽  
Elevated Expression ◽  
The Central Nervous System ◽  
Signaling Activation

Abstract Neuroinflammation and neuron injury are common features of the central nervous system (CNS) diseases. It is of great significance to identify their shared regulatory mechanisms and explore the potential therapeutic targets. Programmed cell death factor 4 (PDCD4), an apoptosis-related molecule, extensively participates in tumorigenesis and inflammatory diseases, but its expression and biological function during CNS neuroinflammation remain unclear. In the present study, utilizing the lipopolysaccharide (LPS)-induced neuroinflammation model in mice, we reported an elevated expression of PDCD4 both in injured neurons and activated microglia of the inflamed brain. A similar change in PDCD4 expression was observed in vitro in the microglial activation model. Silencing PDCD4 by shRNA significantly inhibited the phosphorylation of MAPKs (p38, ERK, and JNK), prevented the phosphorylation and nuclear translocation of NF-κB p65, and thus attenuated the LPS-induced microglial inflammatory activation. Interestingly, LPS also required the MAPK/NF-κB signaling activation to boost PDCD4 expression in microglia, indicating the presence of a positive loop. Moreover, a persistent elevation of PDCD4 expression was detected in the H2O2-induced neuronal oxidative damage model. Knocking down PDCD4 significantly inhibited the expression of proapoptotic protein BAX, suggesting the proapoptotic activity of PDCD4 in neurons. Taken together, our data indicated that PDCD4 may serve as a hub regulatory molecule that simultaneously promotes the microglial inflammatory activation and the oxidative stress-induced neuronal apoptosis within CNS. The microglial PDCD4–MAPK–NF-κB positive feedback loop may exaggerate the vicious cycle of neuroinflammation and neuronal injury and thus may become a potential therapeutic target for neuroinflammatory diseases.

scholarly journals Effect of Prolonged Treatment with Azithromycin, Clarithromycin, or Levofloxacin on Chlamydia pneumoniae in a Continuous-Infection Model

2002 ◽  
Vol 46 (2) ◽  
pp. 409-412 ◽  
Author(s):  
Andrei Kutlin ◽  
Patricia M. Roblin ◽  
Margaret R. Hammerschlag
Keyword(s):  
Chlamydia Pneumoniae ◽  
Day Treatment ◽  
Prolonged Treatment ◽  
Infection Model ◽  
Necrosis Factor Alpha ◽  
Persistent Infections ◽  
Cytokine Levels ◽  
Factor Alpha ◽  
Vitro Model

ABSTRACT Persistent infections with Chlamydia pneumoniae have been implicated in the development of chronic diseases, such as atherosclerosis and asthma. Although azithromycin, clarithromycin, and levofloxacin are frequently used for the treatment of respiratory C. pneumoniae infections, little is known about the dose and duration of therapy needed to treat a putative chronic C. pneumoniae infection. In this study, we investigated the effect of prolonged treatment with azithromycin, clarithromycin, or levofloxacin on the viability of C. pneumoniae and cytokine production in an in vitro model of continuous infection. We found that a 30-day treatment with azithromycin, clarithromycin, and levofloxacin at concentrations comparable to those achieved in the pulmonary epithelial lining fluid reduced but did not eliminate C. pneumoniae in continuously infected HEp-2 cells. All three antibiotics decreased levels of interleukin-6 (IL-6) and IL-8 in HEp-2 cells, but this effect appeared to be secondary to the antichlamydial activity, as the cytokine levels correlated with the concentrations of microorganisms. The levels of IL-1β, IL-4, IL-10, tumor necrosis factor alpha, and gamma interferon were too low to assess the effect of antibiotics. These data suggest that the dosage and duration of antibiotic therapy currently being used may not be sufficient to eradicate a putative chronic C. pneumoniae infection.

scholarly journals Opsonophagocytosis of Chlamydia pneumoniae by Human Monocytes and Neutrophils

2020 ◽  
Vol 88 (7) ◽  
Author(s):  
Mads Lausen ◽  
Mathilde Selmar Pedersen ◽  
Nareen Sherzad Kader Rahman ◽  
Liv Therese Holm-Nielsen ◽  
Faduma Yahya Mohamed Farah ◽  
...  
Keyword(s):  
Chlamydia Pneumoniae ◽  
Mononuclear Cells ◽  
Inflammatory Diseases ◽  
Membrane Attack Complex ◽  
Complement C3 ◽  
Human Monocytes ◽  
Human Respiratory Tract ◽  
Peripheral Blood Mononuclear ◽  
Content Type

ABSTRACT The human respiratory tract pathogen Chlamydia pneumoniae, which causes mild to severe infections, has been associated with the development of chronic inflammatory diseases. To understand the biology of C. pneumoniae infections, several studies have investigated the interaction between C. pneumoniae and professional phagocytes. However, these studies have been conducted under nonopsonizing conditions, making the role of opsonization in C. pneumoniae infections elusive. Thus, we analyzed complement and antibody opsonization of C. pneumoniae and evaluated how opsonization affects chlamydial infectivity and phagocytosis in human monocytes and neutrophils. We demonstrated that IgG antibodies and activation products of complement C3 and C4 are deposited on the surface of C. pneumoniae elementary bodies when incubated in human serum. Complement activation limits C. pneumoniae infectivity in vitro and has the potential to induce bacterial lysis by the formation of the membrane attack complex. Coculture of C. pneumoniae and freshly isolated human leukocytes showed that complement opsonization is superior to IgG opsonization for efficient opsonophagocytosis of C. pneumoniae in monocytes and neutrophils. Neutrophil-mediated phagocytosis of C. pneumoniae was crucially dependent on opsonization, while monocytes retained minor phagocytic potential under nonopsonizing conditions. Complement opsonization significantly enhanced the intracellular neutralization of C. pneumoniae in peripheral blood mononuclear cells and neutrophils and almost abrogated the infectious potential of C. pneumoniae. In conclusion, we demonstrated that complements limit C. pneumoniae infection in vitro by interfering with C. pneumoniae entry into permissive cells by direct complement-induced lysis and by tagging bacteria for efficient phagocytosis in both monocytes and neutrophils.

scholarly journals Production of Chlamydia pneumoniae Proteins in Bacillus subtilis and Their Use in Characterizing Immune Responses in the Experimental Infection Model

2003 ◽  
Vol 10 (3) ◽  
pp. 367-375 ◽  
Author(s):  
Ulla Airaksinen ◽  
Tuula Penttilä ◽  
Eva Wahlström ◽  
Jenni M. Vuola ◽  
Mirja Puolakkainen ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Large Scale ◽  
Chlamydia Pneumoniae ◽  
Signal Sequence ◽  
Expression Vectors ◽  
Infection Model

ABSTRACT Due to intracellular growth requirements, large-scale cultures of chlamydiae and purification of its proteins are difficult and laborious. To overcome these problems we produced chlamydial proteins in a heterologous host, Bacillus subtilis, a gram-positive nonpathogenic bacterium. The genes of Chlamydia pneumoniae major outer membrane protein (MOMP), the cysteine-rich outer membrane protein (Omp2), and the heat shock protein (Hsp60) were amplified by PCR, and the PCR products were cloned into expression vectors containing a promoter, a ribosome binding site, and a truncated signal sequence of the α-amylase gene from Bacillus amyloliquefaciens. C. pneumoniae genes were readily expressed in B. subtilis under the control of the α-amylase promoter. The recombinant proteins MOMP and Hsp60 were purified from the bacterial lysate with the aid of the carboxy-terminal histidine hexamer tag by affinity chromatography. The Omp2 was separated as an insoluble fraction after 8 M urea treatment. The purified proteins were successfully used as immunogens and as antigens in serological assays and in a lymphoproliferation test. The Omp2 and Hsp60 antigens were readily recognized by the antibodies appearing after pulmonary infection following intranasal inoculation of C. pneumoniae in mice. Also, splenocytes collected from mice immunized with MOMP or Hsp60 proteins proliferated in response to in vitro stimulation with the corresponding proteins.

scholarly journals The H2S Donor GYY4137 Stimulates Reactive Oxygen Species Generation in BV2 Cells While Suppressing the Secretion of TNF and Nitric Oxide

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2966 ◽  
Author(s):  
Milica Lazarević ◽  
Emanuela Mazzon ◽  
Miljana Momčilović ◽  
Maria Basile ◽  
Giuseppe Colletti ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Reactive Oxygen Species ◽  
Reactive Oxygen Species Generation ◽  
Reactive Oxygen ◽  
Microglial Cells ◽  
Oxygen Species ◽  
Bv2 Cells ◽  
The Central Nervous System

GYY4137 is a hydrogen sulfide (H2S) donor that has been shown to act in an anti-inflammatory manner in vitro and in vivo. Microglial cells are among the major players in immunoinflammatory, degenerative, and neoplastic disorders of the central nervous system, including multiple sclerosis, Parkinson’s disease, Alzheimer’s disease, and glioblastoma multiforme. So far, the effects of GYY4137 on microglial cells have not been thoroughly investigated. In this study, BV2 microglial cells were stimulated with interferon-gamma and lipopolysaccharide and treated with GYY4137. The agent did not influence the viability of BV2 cells in concentrations up to 200 μM. It inhibited tumor necrosis factor but not interleukin-6 production. Expression of CD40 and CD86 were reduced under the influence of the donor. The phagocytic ability of BV2 cells and nitric oxide production were also affected by the agent. Surprisingly, GYY4137 upregulated generation of reactive oxygen species (ROS) by BV2 cells. The effect was mimicked by another H2S donor, Na2S, and it was not reproduced in macrophages. Our results demonstrate that GYY4137 downregulates inflammatory properties of BV2 cells but increases their ability to generate ROS. Further investigation of this unexpected phenomenon is warranted.

scholarly journals MCP-1 and CCR2 Contribute to Non-Lymphocyte-Mediated Brain Disease Induced by Fr98 Polytropic Retrovirus Infection in Mice: Role for Astrocytes in Retroviral Neuropathogenesis

2004 ◽  
Vol 78 (12) ◽  
pp. 6449-6458 ◽  
Author(s):  
Karin E. Peterson ◽  
John S. Errett ◽  
Tao Wei ◽  
Derek E. Dimcheff ◽  
Richard Ransohoff ◽  
...  
Keyword(s):  
Knockout Mice ◽  
Neurological Disease ◽  
Chemokine Receptors ◽  
Disease Process ◽  
Chemotactic Protein ◽  
The Central Nervous System ◽  
Brain Antibody ◽  
The Brain

ABSTRACT Virus infection of the central nervous system (CNS) often results in chemokine upregulation. Although often associated with lymphocyte recruitment, increased chemokine expression is also associated with non-lymphocyte-mediated CNS disease. In these instances, the effect of chemokine upregulation on neurological disease is unclear. In vitro, several chemokines including monocyte chemotactic protein 1 (MCP-1) protect neurons from apoptosis. Therefore, in vivo, chemokine upregulation may be a protective host response to CNS damage. Alternatively, chemokines may contribute to pathogenesis by stimulating intrinsic brain cells or recruiting macrophages to the brain. To investigate these possibilities, we studied a neurovirulent retrovirus, Fr98, that induces severe non-lymphocyte-mediated neurological disease and causes the upregulation of several chemokines that bind to chemokine receptors CCR2 and CCR5. Knockout mice deficient in CCR2 had reduced susceptibility to Fr98 pathogenesis, with significantly fewer mice developing clinical disease than did wild-type controls. In contrast, no reduction in Fr98-induced disease was observed in CCR5 knockout mice. Thus, signaling through CCR2, but not CCR5, plays an important role in Fr98-mediated pathogenesis. Three ligands for CCR2 (MCP-1, MCP-3, and MCP-5) were upregulated during Fr98 infection of the brain. Antibody-blocking experiments demonstrated that MCP-1 was important for retrovirus-induced neurological disease. In situ hybridization analysis revealed that MCP-1 was expressed by glial fibrillary acidic protein-positive astrocytes. Thus, astrocytes, previously not thought to play an effector role in the disease process were found to contribute to pathogenesis through the production of MCP-1. This study also demonstrates that chemokines can mediate pathogenesis in the CNS in the absence of lymphocytic infiltrate and gives credence to the hypothesis that chemokine upregulation is a mechanism by which retroviruses such as human immunodeficiency virus induce neurological damage.

scholarly journals Chlamydia pneumoniae Infects and Multiplies in Lymphocytes In Vitro

2001 ◽  
Vol 69 (12) ◽  
pp. 7753-7759 ◽  
Author(s):  
Shusaku Haranaga ◽  
Hiroyuki Yamaguchi ◽  
Herman Friedman ◽  
Shin-ichi Izumi ◽  
Yoshimasa Yamamoto
Keyword(s):  
Immune Cells ◽  
Chlamydia Pneumoniae ◽  
Inflammatory Diseases ◽  
Human Peripheral Blood ◽  
Peripheral Blood Lymphocytes ◽  
Host Cells ◽  
Obligate Intracellular Pathogen ◽  
Spleen Lymphocytes ◽  
Lymphocyte Cell

ABSTRACT The obligate intracellular pathogen Chlamydia (Chlamydophila) pneumoniae is known to be associated with some chronic inflammatory diseases, such as atherosclerosis. Interaction between C. pneumoniae and immune cells is important in the development of such diseases. However, susceptibility of immune cells, particularly lymphocytes, to C. pneumoniaeinfection has not been reported, even though lymphocytes play a pivotal role in the development of the diseases caused by this bacterium. In this regard, we examined the susceptibility of lymphocytes to C. pneumoniae infection in vitro. The results demonstrated that human peripheral blood lymphocytes as well as mouse spleen lymphocytes could be infected with C. pneumoniae. Furthermore, purified T lymphocytes as well as established T-lymphocyte cell line cells showed an obvious susceptibility to C. pneumoniaeinfection, indicating that T cells could be one of the host cells for this bacterial infection. These findings reveal a new infection site for C. pneumoniae, i.e., lymphocytes.

scholarly journals Role of the (Mn)superoxide dismutase of Enterococcus faecalis in the in vitro interaction with microglia

Microbiology ◽  
2011 ◽  
Vol 157 (6) ◽  
pp. 1816-1822 ◽  
Author(s):  
Samuele Peppoloni ◽  
Brunella Posteraro ◽  
Bruna Colombari ◽  
Lidia Manca ◽  
Axel Hartke ◽  
...  
Keyword(s):  
Superoxide Dismutase ◽  
Enterococcus Faecalis ◽  
Stress Responses ◽  
Peritoneal Macrophages ◽  
Infection Process ◽  
Microglial Cells ◽  
Infection Model

Enterococcus faecalis is a significant human pathogen worldwide and is responsible for severe nosocomial and community-acquired infections. Although enterococcal meningitis is rare, mortality is considerable, reaching 21 %. Nevertheless, the pathogenetic mechanisms of this infection remain poorly understood, even though the ability of E. faecalis to avoid or survive phagocytic attack in vivo may be very important during the infection process. We previously showed that the manganese-cofactored superoxide dismutase (MnSOD) SodA of E. faecalis was implicated in oxidative stress responses and, interestingly, in the survival within mouse peritoneal macrophages using an in vivo–in vitro infection model. In the present study, we investigated the role of MnSOD in the interaction of E. faecalis with microglia, the brain-resident macrophages. By using an in vitro infection model, murine microglial cells were challenged in parallel with the wild-type strain JH2-2 and its isogenic sodA deletion mutant. While both strains were phagocytosed by microglia efficiently and to a similar extent, the ΔsodA mutant was found to be significantly more susceptible to microglial killing than JH2-2, as assessed by the antimicrobial protection assay. In addition, a significantly higher percentage of acidic ΔsodA-containing phagosomes was found and these also underwent enhanced maturation as determined by the expression of endolysosomal markers. In conclusion, these results show that the MnSOD of E. faecalis contributes to survival of the bacterium in microglial cells by influencing their antimicrobial activity, and this could even be important for intracellular killing in neutrophils and thus for E. faecalis pathogenesis.

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