Total Flavonoids from Camellia oleifera Alleviated Mycoplasma pneumoniae-Induced Lung Injury via Inhibition of the TLR2-Mediated NF-κB and MAPK Pathways.

Mycoplasma pneumoniae (M. pneumoniae) is an atypical bacterial pathogen responsible for community-acquired pneumonia primarily among school-aged children and young adults. Camellia oleifera (C. oleifera) has been used as a medicinal and edible plant in China for centuries, the constituents from which possessed various bioactivities. Notably, flavonoids existing in residues of C. oleifera defatted seeds exhibited significant anti-inflammatory activities. In the present study, we investigated the impact of total flavonoids from C. oleifera (TFCO) seed extract on M. pneumoniae pneumonia. TFCO was obtained using multiple column chromatography methods and identified as kaempferol glycosides via UPLC-HRESIMS. In a M. pneumoniae pneumonia mouse model, TFCO significantly reduced the lung damage, suppressed IL-1ß, IL-6, and TNF-α production, and curbed TLR2 activation triggered by M. pneumoniae. Similarly, in RAW264.7 macrophage cells stimulated by lipid-associated membrane proteins (LAMPs), TFCO suppressed the generation of proinflammatory cytokines and TLR2 expression. Moreover, TFCO diminished the phosphorylation of IκBα, JNK, ERK, p38, and p65 nuclear translocation in vitro. In conclusion, TFCO alleviated M. pneumoniae-induced lung damage via inhibition of TLR2-mediated NF-κB and MAPK pathways, suggesting its potential therapeutic application in M. pneumoniae-triggered lung inflammation.

Extracellular Vesicles Released from Macrophages Infected with Mycoplasma pneumoniae Stimulate Proinflammatory Response via the TLR2-NF-κB/JNK Signaling Pathway.

Mycoplasma pneumoniae (M. pneumoniae, Mp) is an intracellular pathogen that causes pneumonia, tracheobronchitis, pharyngitis, and asthma in humans and can infect and survive in the host cells leading to excessive immune responses. Extracellular vesicles (EVs) from host cells carry components of pathogens to recipient cells and play a role in intercellular communication during infection. However, there is limited knowledge on whether EVs derived from M. pneumoniae-infected macrophages play as intercellular messengers and functional mechanisms. In this study, we establish a cell model of M. pneumoniae-infected macrophages that continuously secrete EVs to further asses their role as intercellular messengers and their functional mechanisms. Based on this model, we determined a method for isolating the pure EVs from M. pneumoniae-infected macrophages, which employs a sequence of operations, including differential centrifugation, filtering, and ultracentrifugation. We identified EVs and their purity using multiple methods, including electron microscopy, nanoparticle tracking analysis, Western blot, bacteria culture, and nucleic acid detection. EVs from M. pneumoniae-infected macrophages are pure, with a 30-200 nm diameter. These EVs can be taken up by uninfected macrophages and induce the production of tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, IL-6, and IL-8 through the nuclear factor (NF)-κB, and mitogen-activated protein kinases (MAPK) signals pathway. Moreover, the expression of inflammatory cytokines induced by EVs relies on TLR2-NF-κB/JNK signal pathways. These findings will help us better understand a persistent inflammatory response and cell-to-cell immune modulation in the context of M. pneumoniae infection.

[Dickkopf-1 inhibits the secretion of MUC5AC induced by Mycoplasma pneumoniae P1-C in mouse lung epithelial cells].

Mycoplasma pneumoniae is the most common pathogen of respiratory tract infection in children and adults. Clinical observation shows that M. pneumoniae infection can cause massive mucus secretion in the respiratory tract, which makes the breathing of patients difficult. Studies have shown that M. pneumoniae infection can cause massive secretion of mucin 5AC (MUC5AC). Adhesin P1 plays an important role in the pathogenesis of M. pneumoniae infection by mediating the adhesion of pathogens to host cells, and the C-terminal residues of P1 (P1-C) are immunogenic. This study investigated the molecular mechanism of Wnt/ß-catenin signaling pathway inhibitor Dickkopf-1 (DKK1) in the secretion of MUC5AC in mouse airway epithelial cells (MAECs) induced by P1-C. Scanning electron microscope and hematoxylin-eosin staining were used to observe the effect of P1-C on mucus secretion of MAECs. Protein chip was used to detect the secretion of cytokines and analyse the enrichment of related signaling pathways induced by P1-C in MAECs. Periodic acid schiff stain (PAS) staining, Tunel staining and Masson staining were used to detect the damage of the lungs of mouse exposed to P1-C. Immunohistochemistry was used to detect the secretion of MUC5AC expression, and Western blotting was used to reveal the molecular mechanism of DKK1-regulated secretion of MUC5AC induced by P1-C protein in MACES. The results showed that P1-C induced the massive secretion of mucus and inflammatory factors in MAECs. During P1-C infection, DKK1 down-regulated janus kinase 2 (JAK2), phosphorylation signaling and transcription activator 1 (p-STAT1) and phosphorylation signaling and activator of transcription 3 (p-STAT3) expression. Overexpression of DKK1 significantly up-regulated the expression of MUC5AC repressor transcription factor fork-head box protein A2 (FOXA2). At the same time, the expression of MUC5AC induced by P1-C was inhibited significantly. It is speculated that DKK1 can effectively reduce the secretion of MUC5AC in MAECs induced by P1-C by inhibiting the JAK/STAT1-STAT3 signaling pathway and up-regulating the expression of FOXA2.

Aspergillus oryzae Fermentation Extract Alleviates Inflammation in Mycoplasma pneumoniae Pneumonia.

The filamentous fungus Aspergillus oryzae, also known as koji mold, has been used for centuries in the production of fermented foods in East Asia. A. oryzae fermentation can produce enzymes and metabolites with various bioactivities. In this study, we investigated whether A. oryzae fermentation extract (AOFE) has any effect on Mycoplasma pneumoniae (Mp) pneumonia. We performed solid-state fermentation of A. oryzae and obtained the ethanol extract. AOFE was analyzed by HPLC, and the major component was identified to be kojic acid. In vitro, AOFE suppressed Mp growth and invasion into A549 lung epithelial cells as determined by the gentamicin protection assay. AOFE treatment also suppressed Mp-stimulated production of tumor necrosis factor (TNF)-α and interleukin (IL)-6 at mRNA and protein levels in murine MH-S alveolar macrophages. In a mouse model of Mp pneumonia, Mp infection induced a marked pulmonary infiltration of neutrophils, which was significantly reduced in mice pre-treated orally with AOFE. AOFE administration also suppressed the production of proinflammatory cytokines and chemokines in the lungs. Collectively, our results show that AOFE has the potential to be developed into a preventive/therapeutic agent for Mp pneumonia.

Essential protein P116 extracts cholesterol and other indispensable lipids for Mycoplasmas.

Mycoplasma pneumoniae, responsible for approximately 30% of community-acquired human pneumonia, needs to extract lipids from the host environment for survival and proliferation. Here, we report a comprehensive structural and functional analysis of the previously uncharacterized protein P116 (MPN_213). Single-particle cryo-electron microscopy of P116 reveals a homodimer presenting a previously unseen fold, forming a huge hydrophobic cavity, which is fully accessible to solvent. Lipidomics analysis shows that P116 specifically extracts lipids such as phosphatidylcholine, sphingomyelin and cholesterol. Structures of different conformational states reveal the mechanism by which lipids are extracted. This finding immediately suggests a way to control Mycoplasma infection by interfering with lipid uptake.

Genetic Manipulation of Mycoplasma pneumoniae.

Mycoplasma pneumoniae is a small cell wall-lacking bacterium that is a common cause of bronchitis and pneumonia in humans. In addition to its clinical importance, M. pneumoniae has recently been considered a promising model organism for synthetic biology because of its small genome size and unique cell structure. At one cell pole, M. pneumoniae forms the attachment organelle that is responsible for adherence to host cells and gliding motility. The attachment organelle is a membrane protrusion and is composed of number of molecules, including adhesin and cytoskeletal proteins. Genetic manipulation techniques are key research approaches for understanding the structure and the function of this unique molecular machinery. In this chapter, standard genetic engineering methods for this species using the Tn4001 transposon vector are described.

Reserve of Wnt/ß-catenin Signaling Alleviates Mycoplasma pneumoniae P1-C-induced Inflammation in airway epithelial cells and lungs of mice.

Mycoplasma pneumoniae (M. pneumoniae) is the most common pathogen of respiratory tract infections in both children and adults. M. pneumoniae P1 adhesin plays an important role in the pathogenesis of M. pneumoniae infection by mediating the attachment of pathogen to host cells. The inoculation of C-terminal residuals of P1 (P1-C) showed a protective role from M. pneumoniae infection. Accumulated evidence suggests that the Wnt/ß-Catenin signaling is implicated in regulation of inflammatory responses to bacterial infections. However, mechanisms underlying the regulatory roles of Wnt signaling in host cells in response to M. pneumoniae infections are incompletely understood. In the present study, the impact and molecular mechanism of Wnt/ß-catenin signaling in immune responses induced by M. pneumoniae P1-C were investigated. The results demonstrated that the P1-C could activate Wnt/ß-catenin and Toll-like receptor (TLR) signaling in primary mouse airway epithelial cells cultured in an air-liquid interface (ALI) state. Interestingly, the inhibition of Wnt/ß-catenin signaling by an adenovirus-mediated Wnt inhibitor Dickkopf-1 (Dkk1) gene transduction alleviated the P1-C induced inflammation fibrosis in mouse lung, accompanied by the reduced expression of epithelial mesenchymal transition (EMT) markers. Mechanistical analysis further demonstrated that the Dkk1 could suppress the expression of JAK2/STAT1-STAT3 and Caspase3, 8/Bax signaling in mouse lung tissues. In vitro study further revealed that XAV939, a small molecule of Wnt/ß-catenin inhibitor, inhibited the P1-C-activated TLR4/MyD88 signaling and cytokine productions in primary mouse airway ALI epithelial cells. This study thus provides an insight into the function of Wnt/ß-catenin signaling in regulation of the pathogenesis of M. pneumoniae infection, suggesting that targeting Wnt/ß-catenin signaling by gene transduction of Dkk1, or pharmacological molecules of inhibitor may be a promised approach that worthy of further investigation in the treatment of M. pneumoniae pneumonia.

Dickkopf-1 inhibits the secretion of MUC5AC induced by Mycoplasma pneumoniae P1-C in mouse lung epithelial cells / 生物工程学报

Mycoplasma pneumoniae is the most common pathogen of respiratory tract infection in children and adults. Clinical observation shows that M. pneumoniae infection can cause massive mucus secretion in the respiratory tract, which makes the breathing of patients difficult. Studies have shown that M. pneumoniae infection can cause massive secretion of mucin 5AC (MUC5AC). Adhesin P1 plays an important role in the pathogenesis of M. pneumoniae infection by mediating the adhesion of pathogens to host cells, and the C-terminal residues of P1 (P1-C) are immunogenic. This study investigated the molecular mechanism of Wnt/β-catenin signaling pathway inhibitor Dickkopf-1 (DKK1) in the secretion of MUC5AC in mouse airway epithelial cells (MAECs) induced by P1-C. Scanning electron microscope and hematoxylin-eosin staining were used to observe the effect of P1-C on mucus secretion of MAECs. Protein chip was used to detect the secretion of cytokines and analyse the enrichment of related signaling pathways induced by P1-C in MAECs. Periodic acid schiff stain (PAS) staining, Tunel staining and Masson staining were used to detect the damage of the lungs of mouse exposed to P1-C. Immunohistochemistry was used to detect the secretion of MUC5AC expression, and Western blotting was used to reveal the molecular mechanism of DKK1-regulated secretion of MUC5AC induced by P1-C protein in MACES. The results showed that P1-C induced the massive secretion of mucus and inflammatory factors in MAECs. During P1-C infection, DKK1 down-regulated janus kinase 2 (JAK2), phosphorylation signaling and transcription activator 1 (p-STAT1) and phosphorylation signaling and activator of transcription 3 (p-STAT3) expression. Overexpression of DKK1 significantly up-regulated the expression of MUC5AC repressor transcription factor fork-head box protein A2 (FOXA2). At the same time, the expression of MUC5AC induced by P1-C was inhibited significantly. It is speculated that DKK1 can effectively reduce the secretion of MUC5AC in MAECs induced by P1-C by inhibiting the JAK/STAT1-STAT3 signaling pathway and up-regulating the expression of FOXA2.

Visualizing translation dynamics at atomic detail inside a bacterial cell.

Translation is the fundamental process of protein synthesis and is catalysed by the ribosome in all living cells1. Here we use advances in cryo-electron tomography and sub-tomogram analysis2,3 to visualize the structural dynamics of translation inside the bacterium Mycoplasma pneumoniae. To interpret the functional states in detail, we first obtain a high-resolution in-cell average map of all translating ribosomes and build an atomic model for the M. pneumoniae ribosome that reveals distinct extensions of ribosomal proteins. Classification then resolves 13 ribosome states that differ in their conformation and composition. These recapitulate major states that were previously resolved in vitro, and reflect intermediates during active translation. On the basis of these states, we animate translation elongation inside native cells and show how antibiotics reshape the cellular translation landscapes. During translation elongation, ribosomes often assemble in defined three-dimensional arrangements to form polysomes4. By mapping the intracellular organization of translating ribosomes, we show that their association into polysomes involves a local coordination mechanism that is mediated by the ribosomal protein L9. We propose that an extended conformation of L9 within polysomes mitigates collisions to facilitate translation fidelity. Our work thus demonstrates the feasibility of visualizing molecular processes at atomic detail inside cells.

Toll-Like Receptor 4 Exacerbates Mycoplasma pneumoniaevia Promoting Transcription Factor EB-Mediated Autophagy.

Mycoplasma pneumoniae (M. pneumoniae) is the most common cause of community-acquired pneumonia. Toll-like receptors (TLRs) play an essential role in pneumonia. The purpose of this study was to investigate the roles of TLR4 in M. pneumoniae. Mice were administrated with 100 µl (1 × 107 ccu/ml) of M. pneumoniae. HE staining was applied for histological analysis. The protein expression was determined by western blot. The cytokine level was detected by ELISA. The results showed that TLR4-deficient mice were protected from M. pneumoniae. However, downregulation of TLR4 inhibited inflammatory response and autophagy. Moreover, transcription factor EB (TFEB) participated in M. pneumoniae-induced inflammatory response and autophagy, while knockdown of TLR4 downregulated TFEB and its nuclear translocation.

Pinocembrin Relieves Mycoplasma pneumoniae Infection­Induced Pneumonia in Mice Through the Inhibition of Oxidative Stress and Inflammatory Response.

Pneumonia is a serious infectious disease with increased morbidity and mortality worldwide. The M. pneumoniae is a major airway pathogen that mainly affects respiratory tract and ultimately leads to the development of pneumonia. The current exploration was aimed to uncover the beneficial properties of pinocembrin against the M. pneumoniae-triggered pneumonia in mice via its anti-inflammatory property. The pneumonia was stimulated to the BALB/c mice via infecting them with M. pneumoniae (100 µl) for 2 days through nasal drops and concomitantly treated with pinocembrin (10 mg/kg) for 3 days. The azithromycin (100 mg/kg) was used as a standard drug. Then the lung weight, nitric oxide, and myeloperoxidase (MPO) activity was assessed. The content of MDA, GSH, and SOD activity was scrutinized using kits. The total cells and DNA amount present in the bronchoalveolar lavage fluid (BALF) was assessed by standard methods. The IL-1, IL-6, IL-8, TNF-α, and TGF contents in the BALF samples and NF-κB level in the lung tissues were assessed using kits. The lung histopathology was assessed microscopically to detect the histological alterations. The 10 mg/kg of pinocembrin treatment substantially decreased the lung weight, nitric oxide (NO) level, and MPO activity. The MDA level was decreased, and GSH content and SOD activity were improved by the pinocembrin treatment. The pinocembrin administered pneumonia animals also demonstrated the decreased total cells, DNA amount, IL-1, IL-6, IL-8, TNF-α, and TGF in the BALF and NF-κB level. The findings of histological studies also witnessed the beneficial role of pinocembrin against M. pneumoniae-infected pneumonia. In conclusion, our findings confirmed that the pinocembrin effectively ameliorated the M. pneumoniae-provoked inflammation and oxidative stress in the pneumonia mice model. Hence, it could be a hopeful therapeutic agent to treat the pneumonia in the future.

Geraniol relieves mycoplasma pneumonia infection-induced lung injury in mice through the regulation of ERK/JNK and NF-κB signaling pathways.

BACKGROUND: Pneumonia is a serious pediatric lung injury disease caused by Mycoplasma pneumoniae (M. pneumoniae) with increasing global prevalence every year. The WHO has reported that nearly 19% of children die due to pneumonia worldwide. OBJECTIVE: The present research was conducted to discover the ameliorative properties of geraniol against M. pneumoniae-provoked pneumonia in mice through the modulation of inflammatory responses. METHODOLOGY: The pneumonia was provoked in the male Swiss albino mice via infecting animals with 100 µl of M. pneumoniae for 2 days and supplemented concurrently with 20 mg/kg of geraniol for 3 days. 100 mg/kg of azithromycin was used as a standard drug. The nitric oxide (NO) level and MPO activity were measured using kits. The SOD activity, GSH, and MDA levels were studied using standard methods. The polymerase chain reaction (PCR) study was performed to examine the M. pneumoniae DNA load. The inflammatory cytokines status was assessed by assay kits. The ERK1/2, JNK1/2, and NF-κB expressions were studied by reverse-transcription (RT-PCR). The lung tissues were analyzed microscopically to investigate the histological alterations. RESULTS: Geraniol treatment effectively reduced lung weight, NO level, and MPO activity in the pneumonia mice. The total cells and M. pneumoniae DNA load were also decreased by the geraniol. The SOD activity and GSH level were improved and MDA was decreased by the geraniol treatment. The IL-1, IL-6, IL-8, TNF-α, and TGF status were appreciably depleted by the geraniol in the pneumonia mice. Geraniol also suppressed the ERK1/2 and NF-κB expressions in the lung tissues. Histological findings also suggest the therapeutic roles of geraniol against pneumonia in mice. CONCLUSION: In summary, our results proved the beneficial roles of geraniol against the M. pneumoniae-provoked pneumonia. Geraniol could be a hopeful therapeutic agent to treat pneumonia in the future.

CC16 Deficiency in the Context of Early-Life Mycoplasma pneumoniae Infection Results in Augmented Airway Responses in Adult Mice.

Studies have shown that club cell secretory protein (CC16) plays important protective roles in the lungs, yet its complete biological functions are unclear. We devised a translational mouse model in order to investigate the impact of early life infections, in the context of CC16 deficiency, on lung function in adult mice. CC16 sufficient (WT) and deficient (CC16-/-) mice were infected with Mycoplasma pneumoniae (Mp) as weanlings and assessed as adults (early life infection model; ELIM) and compared to adult mice infected for only 3 days (adult infection model; AIM). CC16-/- Mp-infected mice had significantly increased airway hyperresponsiveness (AHR) in both models compared to WT mice. However, CC16-/- mice infected in early life (ELIM) displayed significantly increased AHR compared to CC16-/- mice infected in adulthood (AIM). In stark contrast, lung function in ELIM WT mice returned to levels similar to saline-treated controls. While WT mice cleared Mp infection in the ELIM, CC16-/- mice remained colonized with Mp throughout the model, which likely contributed to increased airway remodeling and persistence of Muc5ac expression. When CC16-/- mouse tracheal epithelial cells (MTECs) were infected with Mp, increased Mp colonization and collagen gene expression were also detected compared to WT cells, suggesting that CC16 plays a protective role during Mp infection, in part through epithelial-driven host defense mechanisms.

Mycoplasma pneumoniae CARDS toxin exploits host cell endosomal acidic pH and vacuolar ATPase proton pump to execute its biological activities.

Mycoplasma pneumoniae is the leading cause of bacterial community-acquired pneumonia among hospitalized children in the United States. It is also responsible for a spectrum of other respiratory tract disorders and extrapulmonary manifestations in children and adults. The main virulence factor of M. pneumoniae is a 591 amino acid multifunctional protein called Community Acquired Respiratory Distress Syndrome (CARDS) toxin. The amino terminal region of CARDS toxin (N-CARDS) retains ADP-ribosylating activity and the carboxy region (C-CARDS) contains the receptor binding and vacuolating activities. After internalization, CARDS toxin is transported in a retrograde manner from endosome through the Golgi complex into the endoplasmic reticulum. However, the mechanisms and criteria by which internalized CARDS toxin is transported and activated to execute its cytotoxic effects remain unknown. In this study, we used full-length CARDS toxin and its mutant and truncated derivatives to analyze how pharmacological drugs that alter pH of intracellular vesicles and electrical potential across vesicular membranes affect translocation of CARDS toxin in mammalian cells. Our results indicate that an acidic environment is essential for CARDS toxin retrograde transport to endoplasmic reticulum. Moreover, retrograde transport facilitates toxin clipping and is required to induce vacuole formation. Additionally, toxin-mediated cell vacuolation is strictly dependent on the function of vacuolar type-ATPase.

Determination of metabolic activity in planktonic and biofilm cells of Mycoplasma fermentans and Mycoplasma pneumoniae by nuclear magnetic resonance.

Mycoplasmas are fastidious microorganisms, typically characterised by their restricted metabolism and minimalist genome. Although there is reported evidence that some mycoplasmas can develop biofilms little is known about any differences in metabolism in these organisms between the growth states. A systematic metabolomics approach may help clarify differences associated between planktonic and biofilm associated mycoplasmas. In the current study, the metabolomics of two different mycoplasmas of clinical importance (Mycoplasma pneumoniae and Mycoplasma fermentans) were examined using a novel approach involving nuclear magnetic resonance spectroscopy and principle component analysis. Characterisation of metabolic changes was facilitated through the generation of high-density metabolite data and diffusion-ordered spectroscopy that provided the size and structural information of the molecules under examination. This enabled the discrimination between biofilms and planktonic states for the metabolomic profiles of both organisms. This work identified clear biofilm/planktonic differences in metabolite composition for both clinical mycoplasmas and the outcomes serve to establish a baseline understanding of the changes in metabolism observed in these pathogens in their different growth states. This may offer insight into how these organisms are capable of exploiting and persisting in different niches and so facilitate their survival in the clinical setting.

Protein cleavage influences surface protein presentation in Mycoplasma pneumoniae.

Mycoplasma pneumoniae is a significant cause of pneumonia and post infection sequelae affecting organ sites distant to the respiratory tract are common. It is also a model organism where extensive 'omics' studies have been conducted to gain insight into how minimal genome self-replicating organisms function. An N-terminome study undertaken here identified 4898 unique N-terminal peptides that mapped to 391 (56%) predicted M. pneumoniae proteins. True N-terminal sequences beginning with the initiating methionine (iMet) residue from the predicted Open Reading Frame (ORF) were identified for 163 proteins. Notably, almost half (317; 46%) of the ORFS derived from M. pneumoniae strain M129 are post-translationally modified, presumably by proteolytic processing, because dimethyl labelled neo-N-termini were characterised that mapped beyond the predicted N-terminus. An analysis of the N-terminome describes endoproteolytic processing events predominately targeting tryptic-like sites, though cleavages at negatively charged residues in P1' (D and E) with lysine or serine/alanine in P2' and P3' positions also occurred frequently. Surfaceome studies identified 160 proteins (23% of the proteome) to be exposed on the extracellular surface of M. pneumoniae. The two orthogonal methodologies used to characterise the surfaceome each identified the same 116 proteins, a 72% (116/160) overlap. Apart from lipoproteins, transporters, and adhesins, 93/160 (58%) of the surface proteins lack signal peptides and have well characterised, canonical functions in the cell. Of the 160 surface proteins identified, 134 were also targets of endo-proteolytic processing. These processing events are likely to have profound implications for how the host immune system recognises and responds to M. pneumoniae.

Evaluation of the CARDS toxin and its fragment for the serodiagnosis of Mycoplasma pneumoniae infections.

Mycoplasma pneumoniae (M. pneumoniae) is an important pathogen in community-acquired pneumonia. The community-acquired respiratory distress syndrome (CARDS) toxin is the only known virulence factor of M. pneumoniae. It is worth exploring whether this toxin can be used as a candidate antigen for the serodiagnosis of M. pneumoniae. In this study, the full-length, N-terminal, and C-terminal regions of the CARDS toxin were expressed and purified, and serological reactions were evaluated using ELISA. A total of 184 serum samples were collected and tested using a commercialized test kit. Eighty-seven samples were positive, and 97 samples were negative for infection. The purified recombinant proteins were used as antigens to test the serum via indirect ELISA. The sensitivity of the CARDS toxin, the N-terminal region, and the C-terminal region were 90.8%, 90.8%, and 92.0%, respectively. The specificity of the CARDS toxin, the N-terminal region, and the C-terminal region were 85.6%, 73.2%, and 93.8%, respectively. All three CARDS toxin proteins exhibited good reactivity, of which the C-terminal region had a good discrimination ability in human sera. This may have a potential diagnostic value for M. pneumoniae infections.

Chronic infection with Chlamydia pneumoniae in asthma: a type-2 low infection related phenotype.

BACKGROUND: Chlamydia pneumoniae and Mycoplasma pneumoniae have been implicated in the pathogenesis of asthma and are responsible for chronic inflammation when host immune system fails to eradicate the bacteria. METHOD: We performed a prospective study on 410 patients who underwent a visit at the asthma clinic of CHU of Liege between June 2016 and June 2018 with serology testing for C. pneumoniae and M. pneumoniae. RESULTS: 65% of our asthmatic population had serum IgA and/or IgG towards C. pneumoniae, while only 12.6% had IgM and/or IgG against M. pneumoniae. Compared to seronegative asthmatics, asthmatics with IgA+ and IgG+ against C. pneumoniae were more often male and older with a higher proportion of patients with smoking history. They received higher doses of inhaled corticosteroids (ICS) and displayed lower FEV1/FVC ratio, higher RV/TLC ratio and lower conductance. They had higher levels of fibrinogen, though in the normal range and had lower sputum eosinophil counts. Patients with IgA- and IgG+ against C. pneumoniae were older and had higher blood monocyte counts and alpha-1-antitrypsin levels as compared to seronegative patients. Patients with IgM and/or IgG towards M. pneumoniae were more often males than seronegative asthmatics. In a subpopulation of 14 neutrophilic asthmatics with Chlamydia pneumoniae IgA + /IgG + treated with macrolides, we found a significant decrease in blood neutrophils and normalization of sputum neutrophil count but no effect on asthma quality of life and exacerbations. CONCLUSION: Positive Chlamydia serologic test is more common than positive Mycoplasma serology. Asthmatics with IgA and IgG against C. pneumoniae have more severe disease with increased airway obstruction, higher doses of ICS, more signs of air trapping and less type-2 inflammation.

Three main short-chain fatty acids inhibit the activation of THP-1 cells by Mycoplasma pneumoniae.

The overactivation of macrophages causes chronic inflammatory diseases. Short-chain fatty acids (SCFAs), potential drugs for clinical treatment, are modulators of macrophage inflammatory reaction. Therefore, the modulation of macrophage-mediated cell activity is expected to become a new therapeutic strategy for inflammatory diseases caused by Mycoplasma pneumoniae. In this study, 2 kinds of SCFAs (propionate and butyrate) were found to have anti-inflammatory effects in M. pneumoniae-stimulated THP-1 cells inflammatory. They inhibited the expressions of IL-4, IL-6, ROS, and NLRP3 inflammasome, while enhancing the expressions of IL-10 and IFN-γ. Our study revealed these 2 agents to repress transcriptional activities of NF-κB, which are important modulators of inflammation. Meanwhile, SCFAs can significantly enhance the autophagy induced by M. pneumoniae. Considering that SCFAs have few side effects, they might be the promising adjuvant therapy for the prevention and/or treatment of various inflammatory diseases.

The Sialoglycan Binding Adhesins of Mycoplasma genitalium and Mycoplasma pneumoniae.

Mycoplasma genitalium (Mge) and Mycoplasma pneumoniae (Mpn) are two human pathogens associated with urogenital and respiratory tract infections, respectively. The recent elucidation of the tridimensional structure of their major cytoadhesins by X-ray crystallography and cryo-electron microscopy/tomography, has provided important insights regarding the mechanics of infection and evasion of immune surveillance.