PTPRO inhibits LPS-induced apoptosis in alveolar epithelial cells.

Acute lung injury (ALI) and its severe manifestation, acute respiratory distress syndrome (ARDS), represent critical clinical syndromes with multifactorial origins, notably stemming from sepsis within intensive care units (ICUs). Despite their high mortality rates, no selective cure is available beside ventilation support. Apoptosis plays a complex and pivotal role in the pathophysiology of acute lung injury. Excessive apoptosis of alveolar epithelial and microvascular endothelial cells can lead to disruption of lung epithelial barrier integrity, impairing the body's ability to exchange blood and gas. At the same time, apoptosis of damaged or dysfunctional cells, including endothelial and epithelial cells, can help maintain tissue integrity and accelerate recovery from organ pro-inflammatory stress. The balance between pro-survival and pro-apoptotic signals in lung injury determines patient outcomes, making the modulation of apoptosis an area of intense research in the quest for more effective therapies. Here we found that protein tyrosine phosphatase receptor type O (PTPRO), a poorly understood receptor-like protein tyrosine phosphatase, is consistently upregulated in multiple tissue types of mice under septic conditions and in the lung alveolar epithelial cells. PTPRO reduction by its selective short-interfering RNA (siRNA) leads to excessive apoptosis in lung alveolar epithelial cells without affecting cell proliferation. Consistently PTPRO overexpression by a DNA construct attenuates apoptotic signaling induced by LPS. These effects of PTPTO on cellular apoptosis are dependent on an ErbB2/PI3K/Akt/NFκB signaling pathway. Here we revealed a novel regulatory pathway of cellular apoptosis by PTPRO in lung alveolar epithelial cells during sepsis.

Immune responses induced by Mycobacterium tuberculosis heat-resistant antigen (Mtb-HAg) upon co-administration with Bacillus Calmette-Guérin in mice.

OBJECTIVES: To preliminarily assess the immunogenicity of Mtb-HAg in mice and the synergistic effect provided by HAg when co-immunised with BCG. METHODS: Mice were randomly grouped for different immunisations and then spleens were aseptically removed and lymphocytes were extracted for immediate detection of cytokines transcript levels and stimulation index(SI), cytokine secretion and multifunctional antigen-specific T cells were detected after incubation for different times. RESULTS: HAg extracted from active Mtb is a group of mixed polypeptides with molecular weights of (10-14) kDa. It can significantly stimulate lymphocytes proliferation and increase SI. Injection of HAg alone and in combination with BCG induced significantly higher numbers of multifunctional antigen-specific T cells including CD4+ IFN-γ+, CD4+ IL-2+, CD8+ IFN-γ+, and CD8+ IL-2+ cells than that in BCG-treated mice. Co-immunisation induced the secretion of higher levels of IFN-γ, TNF-α, IL-2 and IL-4 and increased their mRNA expression levels. Significant increases in the transcription levels of IL-10, IL-12 and IL-17 were observed in the co-immunised group with the assistance of HAg. CONCLUSION: We demonstrated that HAg has favourable immunogenicity, triggers a stronger Th1-type immune response and proposed the hypothesis that HAg can be used as a BCG booster to further enhance the benefits of BCG.

Analysis of the components of Mycobacterium tuberculosis heat-resistant antigen (Mtb-HAg) and its regulation of γδ T-cell function.

BACKGROUND: Mycobacterium tuberculosis heat-resistant antigen (Mtb-HAg) is a peptide antigen released from the mycobacterial cytoplasm into the supernatant of Mycobacterium tuberculosis (Mtb) attenuated H37Ra strain after autoclaving at 121 °C for 20 min. Mtb-HAg can specifically induce γδ T-cell proliferation in vitro. However, the exact composition of Mtb-HAg and the protein antigens that are responsible for its function are currently unknown. METHODS: Mtb-HAg extracted from the Mtb H37Ra strain was subjected to LC‒MS mass spectrometry. Twelve of the identified protein fractions were recombinantly expressed in Escherichia coli by genetic engineering technology using pET-28a as a plasmid and purified by Ni-NTA agarose resin to stimulate peripheral blood mononuclear cells (PBMCs) from different healthy individuals. The proliferation of γδ T cells and major γδ T-cell subset types as well as the production of TNF-α and IFN-γ were determined by flow cytometry. Their proliferating γδ T cells were isolated and purified using MACS separation columns, and Mtb H37Ra-infected THP-1 was co-cultured with isolated and purified γδ T cells to quantify Mycobacterium viability by counting CFUs. RESULTS: In this study, Mtb-HAg from the attenuated Mtb H37Ra strain was analysed by LC‒MS mass spectrometry, and a total of 564 proteins were identified. Analysis of the identified protein fractions revealed that the major protein components included heat shock proteins and Mtb-specific antigenic proteins. Recombinant expression of 10 of these proteins in by Escherichia coli genetic engineering technology was used to successfully stimulate PBMCs from different healthy individuals, but 2 of the proteins, EsxJ and EsxA, were not expressed. Flow cytometry results showed that, compared with the IL-2 control, HspX, GroEL1, and GroES specifically induced γδ T-cell expansion, with Vγ2δ2 T cells as the main subset, and the secretion of the antimicrobial cytokines TNF-α and IFN-γ. In contrast, HtpG, DnaK, GroEL2, HbhA, Mpt63, EsxB, and EsxN were unable to promote γδ T-cell proliferation and the secretion of TNF-α and IFN-γ. None of the above recombinant proteins were able to induce the secretion of TNF-α and IFN-γ by αß T cells. In addition, TNF-α, IFN-γ-producing γδ T cells inhibit the growth of intracellular Mtb. CONCLUSION: Activated γδ T cells induced by Mtb-HAg components HspX, GroES, GroEL1 to produce TNF-α, IFN-γ modulate macrophages to inhibit intracellular Mtb growth. These data lay the foundation for subsequent studies on the mechanism by which Mtb-HAg induces γδ T-cell proliferation in vitro, as well as the development of preventive and therapeutic vaccines and rapid diagnostic reagents.

A Novel Myricetin Derivative with Anti-cancer Properties Induces Cell Cycle Arrest and Apoptosis in A549 Cells.

Lung cancer is the leading cause of cancer-related deaths worldwide, synthesizing and screening of novel anti-cancer drugs provides an alternative therapeutic strategy for renewal of the chemotherapy regimens against lung cancer. To this end, several compounds were synthesized based on the modification of the original myricetin, and their anti-tumor activity against the human non-small cell lung cancer (NSCLC) A549 cells were measured. Among the myricetin derivatives, S4-10 has displayed the highest antitumor efficacy in dose-dependent manner. The proliferation of A549 cells were significantly attenuated by given 6 µM of S4-10 both in vitro and in vivo. Further, the treatment of S4-10 also results in the inhibition of cell migration and invasiveness and the induction of cell apoptosis and G2 cycle arrest of A549 cells. Moreover, we found that S4-10 inhibits the progression of A549 cells through the sterol biosynthetic-cell apoptosis axis. These findings shed the light of developing S4-10 as a promising treatment agent for NSCLC.

Peripheral blood non-canonical small non-coding RNAs as novel biomarkers in lung cancer.

One unmet challenge in lung cancer diagnosis is to accurately differentiate lung cancer from other lung diseases with similar clinical symptoms and radiological features, such as pulmonary tuberculosis (TB). To identify reliable biomarkers for lung cancer screening, we leverage the recently discovered non-canonical small non-coding RNAs (i.e., tRNA-derived small RNAs [tsRNAs], rRNA-derived small RNAs [rsRNAs], and YRNA-derived small RNAs [ysRNAs]) in human peripheral blood mononuclear cells and develop a molecular signature composed of distinct ts/rs/ysRNAs (TRY-RNA). Our TRY-RNA signature precisely discriminates between control, lung cancer, and pulmonary TB subjects in both the discovery and validation cohorts and outperforms microRNA-based biomarkers, which bears the diagnostic potential for lung cancer screening.

CXCR2 antagonist attenuates neutrophil transmigration into brain in a murine model of LPS induced neuroinflammation.

Sepsis-associated encephalopathy (SAE) is a devastating neurological complication of sepsis with intolerable high motility. SAE is accompanied with brain vascular injury, endothelial hyperpermeability, and neutrophil infiltration into the brain tissue, key inflammatory processes leading to further brain edema and neuronal cell apoptosis. Recent studies from us and others suggest that the chemokine receptor C-X-C Motif Chemokine Receptor 2 (CXCR2) is crucial for neutrophil recruitment during SAE. Here we use CXCR2 antagonist SB225002 to characterize the role of CXCR2 in brain infiltration of neutrophil in a murine model of SAE. Systemic administration of high-dose LPS (10 mg/kg) induced evident neutrophil infiltration into the cerebral cortex in wild-type mice. However, CXCR2 antagonist SB225002 markedly attenuated neutrophil infiltration into brain. The CXCR2 expression on neutrophils in the peripheral circulation was dramatically downregulated in response to this LPS dose, and endothelial CXCR2 was significantly upregulated, suggesting endothelial but not neutrophil CXCR2 plays a more important role in neutrophil infiltration into brain. Strikingly, although these CXCR2 antagonist SB225002 treated mice displayed reduced neutrophil infiltration, no change in neutrophil rolling and adhesion was observed. Furthermore, we confirmed that CXCR2 agonist CXCL1 induced a marked increase in actin stress fiber synthesis and paracellular gap formation in cultured cerebral endothelial cells, which is attenuated by SB225002. Thus, these results demonstrate a selective role for endothelial CXCR2 to regulate cerebral vascular permeability and neutrophil transmigration in high-dose LPS induced neuroinflammation, and also suggest a therapeutic potential of CXCR2 antagonist SB225002 in SAE.

EZH2 upregulation by ERα induces proliferation and migration of papillary thyroid carcinoma.

BACKGROUND: The incidence of papillary thyroid carcinoma (PTC) has been increasing worldwide in recent years. Therefore, novel potential therapeutic targets for PTC are urgently needed. Enhancer of zeste homolog 2 (EZH2), a methyltransferase belonging to PRC2, plays important roles in epigenetic silencing and cell cycle regulation. EZH2 overexpression has been found in several malignant tumor tissues, while its expression and function in PTC are largely unknown. METHODS: Sixty-five cases of PTC tissue confirmed by pathology and 30 cases of normal thyroid tissue adjacent to PTC tissue were collected from patients undergoing surgical treatment, between February 2003 and February 2006. We investigated the clinic pathologic significance of EZH2 expression using Realtime-PCR and IHC in 65 human PTC tissues and 30 normal thyroid tissue samples. The EZH2 expression in human PTC cell lines (K1 and W3) and the normal thyroid follicular epithelial cell line Nthy-ori 3-1 was analyzed by Western blotting and Realtime PCR. The expressions of ERα and ERß in cell lines were analyzed by Realtime PCR.The tumor cell biological behavior was evaluated by CCK8 assay, colony formation assay, transwell migration assay and xenograft tumors model. RESULTS: Higher rate of EZH2 expression was found in PTC tissues than in normal thyroid tissues, EZH2 expression is associated with lymph node metastasis and recurrent. Inhibition of EZH2 in PTC cell lines downregulates cellular proliferation and migration. PTC is a disease with high incidence of female and E2-ERα upregulates EZH2 expression. CONCLUSIONS: These results suggest a potential role of EZH2 for the PTC growth and metastasis. As a novel therapy, a pharmacological therapy targeting EZH2 has full potential in treatment of PTC.

TLR4-NOX2 axis regulates the phagocytosis and killing of Mycobacterium tuberculosis by macrophages.

BACKGROUND: Macrophages stand at the forefront of both innate and adapted immunity through their capacities to recognize, engulf, and eliminate foreign particles, and to stimulate adapted immune cells. They are also involved in controlling pro- and anti-inflammatory pathways. Macrophage activity against Mycobacterium tuberculosis (M. tuberculosis) has been shown to involve Toll-like receptor (TLR) activation and ROS production. Previous studies have shown that lipopolysaccharide (LPS), through TLR4, could activate macrophages, improve their bactericidal ROS production, and facilitate anti-infective immune responses. We sought to better understand the role of the TLR4-NOX2 axis in macrophage activation during M. tuberculosis infection. METHODS: THP-1 macrophages and PMA primed THP-1 macrophages [THP-1(A)] were treated with LPS and infected by M. tuberculosis. Cells were analyzed by flow cytometry for TLR4 expression, ROS production, phagocytosis, and killing of M. tuberculosis. Western blotting was used to analyze NOX2 expression. Inhibitors of the TLR4-NOX2 pathway were used to assess this pathway's role in these processes, and their role in LPS activation of macrophages. RESULTS: We found that THP1-derived macrophages or PMA primed THP-1 macrophages exhibit higher surface TLR4 levels and increased NOX2 expression levels following LPS treatment. M. tuberculosis infection reduced these levels, but LPS was able to limit the negative effects of M.tb. Additionally, LPS increases THP-1(A) cells' bactericidal activities including phagocytosis, ROS production, and destruction of M. tuberculosis. Significantly, all of these activities are impaired when TLR4 or NOX2 are inhibited. CONCLUSION: These studies demonstrate the importance of the TLR4-NOX2 axis in M. tuberculosis elimination by macrophages and may lead to novel therapies for tuberculosis and other bacterial infections.

Mycobacterium tuberculosis PE_PGRS45 (Rv2615c) Promotes Recombinant Mycobacteria Intracellular Survival via Regulation of Innate Immunity, and Inhibition of Cell Apoptosis.

Tuberculosis (TB), a bacterial infectious disease caused by Mycobacterium tuberculosis (M. tuberculosis), is a significant global public health problem. Mycobacterium tuberculosis expresses a unique family of PE_PGRS proteins that have been implicated in pathogenesis. Despite numerous studies, the functions of most PE_PGRS proteins in the pathogenesis of mycobacterium infections remain unclear. PE_PGRS45 (Rv2615c) is only found in pathogenic mycobacteria. In this study, we successfully constructed a recombinant Mycobacterium smegmatis (M. smegmatis) strain which heterologously expresses the PE_PGRS45 protein. We found that overexpression of this cell wall-associated protein enhanced bacterial viability under stress in vitro and cell survival in macrophages. MS_PE_PGRS45 decreased the secretion of pro-inflammatory cytokines such as IL-1ß, IL-6, IL-12p40, and TNF-α. We also found that MS_PE_PGRS45 increased the expression of the anti-inflammatory cytokine IL-10 and altered macrophage-mediated immune responses. Furthermore, PE_PGRS45 enhanced the survival rate of M. smegmatis in macrophages by inhibiting cell apoptosis. Collectively, our findings show that PE_PGRS45 is a virulent factor actively involved in the interaction with the host macrophage.

Stimulation of TLR4 by LMW-HA induces metastasis in human papillary thyroid carcinoma through CXCR7.

In inflammatory sites, high molecular weight hyaluronan fragments are degraded into lower molecular weight hyaluronan fragments (LMW-HA) to regulate immune responses. However, the function of LMW-HA in PTC progression remains to be elucidated. In this study, we found that receptor of LMW-HA, TLR4, was aberrantly overexpressed in PTC tissues and cell line W3. Exposure of W3 cells to LMW-HA promoted cell proliferation and migration via TLR4. Knockdown of TLR4 has provided evidence that TLR4 is essential for LMW-HA-induced CXCR7 expression, which is responsible for LMW-HA-induced proliferation and migration of W3 cells. In tumor-bearing adult nude mice, stimulation of LMW-HA on W3 cells promotes CXCR7 expression in tumor masses (P = 0.002) and tumor growth (P < 0.001). To further confirm our findings, we investigated the clinicopathologic significance of TLR4 and CXCR7 expression using immumohistochemistry in 135 human PTC tissues and 56 normal thyroid tissue samples. Higher rates of TLR4 (53%) and CXCR7 (24%) expression were found in PTC tissues than in normal tissues. Expression of TLR4 or CXCR7 is associated with tumor size and lymph node metastasis. Therefore, LMW-HA may contribute to the development of PTC via TLR4/CXCR7 pathway, which may be a novel target for PTC immunomodulatory therapy.

[Oxidative damage effect of the serum of severe preeclamptic patients on human umbilical vein endothelial cell].

OBJECTIVE: To investigate oxidative damage effect of the serum of severe preeclamptic patients on human umbilical vein endothelial cells (HUVEC). METHODS: (1) HUVEC were randomly divided into 4 groups according to the following: blank group as control, normal group added 20% normal sera of pregnant women, group PE added 20% sera of severe preeclamptic patients, and group PE + Cat added 20% sera of severe preeclamptic patients plus 3×10(3) U/ml catalase. After cultured for 24 hours, the injury morphology and APO2.7 expression of HUVEC were detected by transmission electron microscopy and flow cytometry respectively. (2) Under the real-time scanning by laser scanning confocal microscopy, HUVEC were randomly divided into 4 groups according to the following: control group added 100 µmol/L H2O2 as positive control, normal group, group PE, and group PE + Cat. HUVEC of each group was scanned for 120 seconds to determine levels of reactive oxidative species (ROS), calcium homeostasis, and mitochondria membrane potential. RESULTS: (1) Obvious injury morphology of HUVEC was observed in group PE, and it was obviously improved by catalase in group PE + Cat. Percentage of HUVEC expressed APO2.7 was (37.8 ± 1.1)% in group PE, which was significantly higher than (13.4 ± 1.1)% in blank group or (13.5 ± 1.5)% in normal group, but significantly lower than (19.2 ± 1.6)% in group PE + Cat (all P < 0.01). (2) The fluorescence intensity curves of intracellular ROS and calcium showed slowly rising in group PE, but no obvious changes in normal group and PE + Cat. The values of ROS and calcium in group PE (12.0 ± 1.3, 4.1 ± 0.7) were higher than those in normal group (1.1 ± 0.4, 0.6 ± 0.4), but lower than those in group PE + Cat (1.5 ± 0.5, 0.9 ± 0.5; all P < 0.01). CONCLUSION: The serum of severe preeclamptic patients caused oxidative damage on HUVEC by increasing intracellular ROS generation, calcium overload, and decreasing mitochondrial membrane potential.

Immunological effects of the PE/PPE family proteins of Mycobacterium tuberculosis and related vaccines.

Tuberculosis (TB) is a chronic infectious disease caused by Mycobacterium tuberculosis (Mtb), and its incidence and mortality are increasing. The BCG vaccine was developed in the early 20th century. As the most widely administered vaccine in the world, approximately 100 million newborns are vaccinated with BCG every year, which has saved tens of millions of lives. However, due to differences in region and race, the average protective rate of BCG in preventing tuberculosis in children is still not high in some areas. Moreover, because the immune memory induced by BCG will weaken with the increase of age, it is slightly inferior in preventing adult tuberculosis, and BCG revaccination cannot reduce the incidence of tuberculosis again. Research on the mechanism of Mtb and the development of new vaccines against TB are the main strategies for preventing and treating TB. In recent years, Pro-Glu motif-containing (PE) and Pro-Pro-Glu motif-containing (PPE) family proteins have been found to have an increasingly important role in the pathogenesis and chronic protracted infection observed in TB. The development and clinical trials of vaccines based on Mtb antigens are in progress. Herein, we review the immunological effects of PE/PPE proteins and the development of common PE/PPE vaccines.

Particulate matter promotes the epithelial to mesenchymal transition in human lung epithelial cells via the ROS pathway.

OBJECTS: Epidemiologic studies have linked exposure to airborne pollutant particulate matter (PM) with increased rates of chronic cardiopulmonary diseases, including asthma and idiopathic pulmonary fibrosis (IPF). Several investigations have suggested that the epithelial-to-mesenchymal transition (EMT) may contribute to the complex pathobiology of environmental exposure-mediated pulmonary fibrosis. The present study was designed to characterize the mechanisms of PM-mediated EMT in human lung epithelial cells (HBECs). METHODS AND RESULTS: PM induced significant dose (0-100 µg/ml) and time (0-72 h)-dependent increases in transforming growth factor ß (TGFß) and fibronectin (FN) protein levels in HBECs lysates. PM-activated TGFß and FN protein production in HBECs was prevented by the antioxidant N-acetyl-cysteine (NAC, 5 mM). Furthermore, the NF-κB inhibitor BAY11-7082 (5 µM) abolished PM-induced FN production in HBECs. Biomarkers of EMT (ACTA2, SNAIL1 and SNAIL2) in PM-treated HBECs were significantly increased at the mRNA level compared to control cells. CONCLUSIONS: These results demonstrate that PM increases protein levels of TGFß and FN via reactive oxygen species (ROS)-dependent pathways. In addition, PM exposure induces EMT in human lung epithelial cells, supporting a novel mechanism for PM-induced pulmonary fibrosis.

Mycobacterium tuberculosis PE8 (Rv1040c) Promotes the Intracellular Survival of Recombinant Mycobacterium by Regulating Host Inflammatory Cytokines and Inhibiting Cell Late Apoptosis.

Tuberculosis is an important chronic and often fatal infectious disease mainly caused by the bacterium Mycobacterium tuberculosis (Mtb). Mtb is one of the most successful pathogens that harbors several potential virulence factors not found in nonpathogenic mycobacteria. As the Mtb cell envelope is closely associated with its virulence and resistance, it is very important to understand the cell envelope for better treatment of causative pathogen. There is increasing evidence that Pro-Glu (PE) and Pro-Pro-Glu (PPE) proteins are the major effectors of virulence and persistence encoded in the Mtb H37Rv genome. However, the function of PE8 has not been explored to date. In this study, we heterologously expressed PE8 in nonpathogenic, fast-growing M. smegmatis to investigate the interaction between PE8 and the host to determine its possible biological functions. We found that recombinant M. smegmatis cells expressing PE8 were less susceptible to sodium dodecyl sulfate-induced surface stress compared with those expressing the empty vector, suggesting that PE8 may be involved in stress responses. In addition, macrophages infected with PE8-expressing M. smegmatis produced obviously lower levels of the proinflammatory factor IL-1ß, IL-6, and TNF-α and higher levels of the inhibitory factor IL-10. We further found that PE8 promoted M. smegmatis survival within macrophages by inhibiting late apoptosis of macrophages. Collectively, selective targeting of the PE/PPE protein family offers an untapped opportunity to the development of more effective and safer drugs against Mtb infection.

Transcriptional analysis of human peripheral blood mononuclear cells stimulated by Mycobacterium tuberculosis antigen.

Background: Mycobacterium tuberculosis antigen (Mtb-Ag) is a polypeptide component with a molecular weight of 10-14 kDa that is obtained from the supernatant of the H37Ra strain after heat treatment. It stimulates the activation and proliferation of γδT cells in the blood to produce an immune response against tuberculosis. Mtb-Ag is therefore crucial for classifying and detecting the central genes and key pathways involved in TB initiation and progression. Methods: In this study, we performed high-throughput RNA sequencing of peripheral blood mononuclear cells (PBMC) from Mtb-Ag-stimulated and control samples to identify differentially expressed genes and used them for gene ontology (GO) and a Kyoto Encyclopedia of Genomes (KEGG) enrichment analysis. Meanwhile, we used PPI protein interaction network and Cytoscape analysis to identify key genes and qRT-PCR to verify differential gene expression. Single-gene enrichment analysis (GSEA) was used further to elucidate the potential biological functions of key genes. Analysis of immune cell infiltration and correlation of key genes with immune cells after Mtb-Ag-stimulated using R language. Results: We identified 597 differentially expressed genes in Mtb-Ag stimulated PBMCs. KEGG and GSEA enrichment analyzed the cellular pathways related to immune function, and DEGs were found to be primarily involved in the TNF signaling pathway, the IL-17 signaling pathway, the JAK-STAT signaling pathway, cytokine-cytokine receptor interactions, and the NF-κB signaling pathway. Wayne analysis using GSEA, KEGG, and the protein-protein interaction (PPI) network showed that 34 genes, including PTGS2, IL-1ß, IL-6, TNF and IFN-γ et al., were co-expressed in the five pathways and all were up-regulated by Mtb-Ag stimulation. Twenty-four DEGs were identified using qRT-PCR, including fourteen up-regulated genes (SERPINB7, IL20, IFNG, CSF2, PTGS2, TNF-α, IL36G, IL6, IL10, IL1A, CXCL1, CXCL8, IL4, and CXCL3) and ten down-regulated genes (RTN1, CSF1R CD14, C5AR1, CXCL16, PLXNB2, OLIG1, EEPD1, ENG, and CCR1). These findings were consistent with the RNA-Seq results. Conclusion: The transcriptomic features associated with Mtb-Ag provide the scientific basis for exploring the intracellular immune mechanisms against Mtb. However, more studies on these DEGs in pathways associated with Mtb-Ag stimulation are needed to elucidate the underlying pathologic mechanisms of Mtb-Ag during Mtb infection.

[H2O2 promotes neutrophil adherence and injury of human umbilical vein endothelial cells].

To explore the role of hydrogen peroxide (H2O2) in promoting polymorphonuclear neutrophils adherence and injury of human umbilical vein endothelial cells (HUVECs), the ordinary optical microscope and scanning electron microscopy were used to observe the adherence and injury after HUVECs co-cultured with neutrophils pretreated by extracellular H2O2 (HUVECs and neutrophils co-culture without H2O2 pretreatment as control), and the adhesion rates of neutrophils were measured through cell count test. The percentages of HUVECs expressing intercellular adhesion molecule 1 (ICAM-1) and Apo2.7 were detected by flow cytometry. After being cocultured with the neutrophils pretreated by extracellular H2O2, HUVECs showed obvious injury changes, such as round or oval shape, shortened or disappeared microvilli, and membrane structural damage; The adhesion rate of neutrophils was (57.74 ± 9.18)%, which was significantly higher than that in control [(23.12 ± 6.43)%, P < 0.01, n = 8]; The percentages of HUVECs expressing ICAM-1 and Apo2.7 were (44.69 ± 1.52)% and (39.29 ± 1.81)% respectively, which were significantly higher than those in control [(21.79 ± 1.43)% and (9.79 ± 1.43)%] (P < 0.01, n = 8). The results suggest that extracellular H2O2 can promote the neutrophils adherence and injury of HUVECs.

[Prokaryotic expression and identification of PPE15 protein from Mycobacterium tuberculosis and preparation of rabbit polyclonal antibodies].

Objective To clone, express and purify PPE15 recombinant protein from Mycobacterium tuberculosis (H37Rv), as well as prepare and characterize its rabbit polyclonal antibody. Methods By The PPE15 gene was amplified from the genome of Mycobacterium tuberculosis H37Rv by PCR, and the His-tagged prokaryotic PPE15 prokaryotic expression plasmid pET28a-PPE15 was constructed by homologous recombination cloning technique, and transformed into E. coli BL21 (DE3). PPE15 expression was induced by isopropyl-ß-D-thiogalactopyranoside (IPTG). Recombinant PPE15 was identified by SDS-PAGE, and further purified by affinity chromatography with a Ni-NTA column. The renaturation purified PPE15 protein was used to immunize New-Zealand rabbit to prepare polyclonal antibodies. The antibody specificity was analyzed by Western blot analysis, and antibody titer was determined by indirect ELISA. Results Recombinant prokaryotic PPE15 protein was successfully expressed and purified with a molecular weight of 38 kDa. The purified PPE15 protein exhibited positive reaction with the serum of TB patients and the PPE15 protein, the titer of the polyclonal antibodies reaches more than 1:1 300 480. Conclusion The recombinant protein PPE15 was successfully expressed and purified, and high titer rabbit-derived polyclonal antibody was prepared which provided an experimental basis for further functional studies of PPE15 protein.

[Establishment of a THP-1 macrophage model infected by recombinant Mycobacterium smegmatis expressing green fluorescent protein].

Objective To establish a THP-1 macrophage model infected by Mycobacterium smegmatis expressing green fluorescent protein (GFP), to quickly locate and visually detect Mycobacterium smegmatis, and to provide a tracer tool to identify the pathogenesis of tuberculosis and develop new tuberculosis vaccines. Methods The enhanced green fluorescent protein (EGFP) gene sequence was amplified by PCR using pEGFP-N1 plasmid as a template to obtain the coding gene of EGFP, and the amplified product was cloned into the vector pALACE to establish the recombinant plasmid pALACE-EGFP. Electroporation transformed the pALACE-EGFP into Mycobacterium smegmatis, and recombinant Mycobacterium smegmatis clones were screened by hygromycin resistance. After expanded culture, the smears were observed by fluorescence microscopy. The THP-1 macrophages were infected with recombinant Mycobacterium smegmatis, and the expression of EGFP was observed. Results The recombinant plasmid pALACE-EGFP was constructed appropriately. The recombinant Mycobacterium smegmatis was observed under fluorescence microscope. And it was confirmed that EGFP was expressed in recombinant Mycobacterium smegmatis, and THP-1 macrophages emitted green fluorescence after infection. Conclusion The successful establishment of recombinant Mycobacterium smegmatis expressing EGFP protein provides insights for investigating infection and pathogenesis of Mycobacterium tuberculosis.

[Protein tyrosine phosphatase receptor type O (PTPRO) promotes phagocytic activity of alveolar epithelial cells via activating AKT signal pathway in LPS induced acute lung injury].

Objective To investigate the effect of protein tyrosine phosphatase receptor type O (PTPRO) on the phagocytic activity of alveolar epithelial cells in LPS-induced acute lung injury. Methods Mice were randomly divided into the normal control group and LPS stimulation group. The infiltration of inflammatory cells was detected by HE staining. The cytokine TNF-α level in lung was analyzed by ELISA. Western blotting was performed to detect the effect of LPS on PTPRO protein expression in lung. After the expression of PTPRO in MLE-12 cells was silenced by siRNA in vitro, flow cytometry was used to detect the effects of LPS and PTPRO siRNA on the phagocytic activity of MLE-12 cells, and the effects of LPS and PTPRO siRNA on the expression of PTPRO, AKT and phosphorylated AKT protein were measured by Western blotting. Results After the establishment of murine acute lung injury model by LPS injection(1 mg/kg), the infiltrated polymorphonuclear leukocytes were markedly increased. The level of TNF-α in lung tissue and the expression of PTPRO in MLE-12 cells were both significantly increased after LPS stimulation. However, the activity of MLE-12 cells to phagocytose fluorescent microbeads was evidently decreased after silencing PTPRO. Furthermore, silencing PTPRO induced a remarkable decrease in the phosphorylation of AKT in MLE-12 cells. Conclusion PTPRO can promote phagocytic activity of MLE-12 cells via activating AKT signaling pathway.

Activation of Nrf2 modulates protective immunity against Mycobacterium tuberculosis infection in THP1-derived macrophages.

Tuberculosis (TB), caused by mycobacterium tuberculosis (M. tuberculosis) infection, is one of the leading causes of death globally and poses a threat to public health. During infection, M. tuberculosis causes redox imbalance and dysfunctions of protective immunity. Transcription factor nuclear factor erythroid 2 (NF-E2)-related factor (Nrf2) is a major modulator of cellular redox homeostasis via transcriptional induction of cytoprotective genes to protect cell against the damage from insults. Thus, we hypothesize that Nrf2 may regulate protective immunity against M. tuberculosis. RNA-seq and immunoblotting results suggested that the expression of Nrf2 protein increased after M. tuberculosis infection, and decreased upon long-term M. tuberculosis infection, while Keap1 protein maintained a low expression level during M. tuberculosis infection. Furthermore, Nrf2 activator sulforaphane (SFN) decreased proinflammatory cytokines production, phagocytosis and host cell apoptosis, while increasing ROS levels and promoting autophagy in THP1 macrophages infected with M. tuberculosis. In addition, SFN-activated Nrf2 augmented bacterial killing by macrophages, which might be due to the regulation of protective immunity via Nrf2. Combined, our results extend the understanding of the complex innate immunity regulation by Nrf2 against mycobacterial infection. Also, these findings suggested that the regulation of Nrf2 signaling cascade could be used as a therapeutic target for the treatment of TB patients and the development of better anti-TB vaccines.