Fibroblast transdifferentiation promotes conversion of M1 macrophages and replenishment of cardiac resident macrophages following cardiac injury in mice.

Resident cardiac macrophages play important roles in homeostasis, maintenance of cardiac function, and tissue repair. After cardiac injury, monocytes infiltrate the tissue, undergo phenotypic and functional changes, and are involved in inflammatory injury and functional remodelling. However, the fate of cardiac infiltrating/polarized macrophages and the relationship between these cells and resident cardiac macrophage replenishment following injury remain unclear. Our results showed that angiotensin II induces cardiac fibroblast transdifferentiation into cardiac myofibroblasts (MFBs). In cocultures with MFBs and murine macrophages, the MFBs promoted macrophage polarization to M1 phenotype, followed by selective apoptosis, which was associated with TNF/TNFR1 axis and independent of NO production. Surprisingly, after 36 h of coculture, the surviving macrophages were converted to M2 phenotype and settled in heart, which was dependent on leptin produced by MFBs or polarized macrophages via the PI3K or Akt pathway. CCR2+ CD45.2+ cells adoptively transferred into CD45.1+ mice with viral myocarditis, differentiated into CD45.2+ CCR2+ CX3CR1+ M2 cells during the resolution of inflammation and settled within the heart. Our data highlight a novel mechanism related to the renewal or replenishment of cardiac resident macrophages following cardiac injury; and suggest that transdifferentiation of cardiac fibroblasts may promote the resolution of inflammation.

The role of B regulatory (B10) cells in inflammatory disorders and their potential as therapeutic targets.

Over the past decade, studies have identified subset of B cells, which play suppressive functions in additions to the conventional functions of B cells: antigen processing and presentation, activation of T cells and antibody productions. Because of their regulatory function, they were named as B regulatory cells (Bregs). Bregs restrict the severity of autoimmune disorders in animal disease models such as experimental autoimmune myocarditis (EAM), experimental autoimmune encephalitis (EAE), and collagen-induced arthritis (CIA) but can contribute to the development of infection and cancer. In humans, the roles of B regulatory cells in autoimmune diseases have not been clearly established because of the inconsistent findings from many researchers. This is believed to arise from the speculated fact that Bregs lack specific marker, which can be used to identify and characterize them in human diseases. The CD19+CD24hiCD38hiCD1dhiB cells have been associated with the regulatory function. Available evidences highlight the relevance of increasing IL-10-producing B cells in autoimmune diseases and the possibility of serving as new therapeutic targets in inflammatory disorders. This review empanels the functions of Bregs in autoimmune diseases in both human and animal models, and further evaluates the possibility of Bregs as therapeutic targets in inflammatory disorders. Consequently, this might help identify possible research gaps, which need to be clarified as researchers speculate the possibility of targeting some subsets of Bregs in the treatment of inflammatory disorders.

Dual faced HMGB1 plays multiple roles in cardiomyocyte senescence and cardiac inflammatory injury.

High mobility group box 1 (HMGB1) is constitutively expressed by many cells. In cells, HMGB1 is a transcription factor or transcription enhancer that is involved in nucleosome sliding, DNA repair, V(D)J recombination, telomere homeostasis, autophagy and viral sensing. HMGB1 can also be secreted or released by stressed cells and serves as an alarmin, cytokine or growth factor to activate the immune response. This protein facilitates CD4+ T cell differentiation and tissue repair through binding with its receptors, including toll-like receptors (TLRs) and the receptor for advanced glycation end-products (RAGE). Recent works have established that HMGB1 plays many vital functions in cardiac inflammatory injury, cardiac regeneration and remodelling. The present review addresses the novel role of HMGB1 in secretion and cardiomyocyte senescence and in the dual faced roles of HMGB1 in cardiac inflammatory injury, inflammatory resolution and cardiac regeneration and remodelling following cardiac injury.

Obesity May Provide Pro-ILC3 Development Inflammatory Environment in Asthmatic Children.

The prevalence of obesity in children has dramatically increased in the last few decades, and obesity has also emerged as an important risk factor for asthma. Innate mechanisms have been shown to be involved in both diseases, particularly through the recently described innate lymphoid cells (ILCs), in which ILC3s have been linked to obesity both in human and in murine models. The aim of this study was to explore whether being overweight in asthmatic children was associated with elevated circulating ILC3 or elevated messenger RNA (mRNA) levels of RORC, IL-17A, and IL-22. Our results showed significantly elevated ILC3 frequencies in overweight asthmatic children compared with nonoverweight controls based on the detection of Lin+CD127+IL-23R+ cells by flow cytometry. Moreover, elevated ILC3 frequencies positively correlated with the mRNA expression of RORC which has been identified as a transcription factor of ILC3s. The relative mRNA expression level of IL-17A was also upregulated in overweight compared to nonoverweight children, as was the relative mRNA level of IL-22. However, there were no correlations between ILC3 frequencies or the expressions of RORC, IL-17A, and IL-22 and asthma severity. These results suggested that childhood obesity is an independent factor that is associated with an elevated frequency of circulating ILC3s and higher expressions of RORC, IL-22, and IL-17A.

HtrA1 up-regulates expression of MMPs via Erk1/2/Rock-dependent pathways.

BACKGROUND: There are few studies that have identified the potential role of a high temperature requirement A1 (HtrA1) in intervertebral disc degeneration (IDD). This study was undertaken to investigate the regulatory role of HtrA1 in the pathogenesis of IDD. MATERIAL AND METHODS: The mRNA levels of HtrA1 and matrix metalloproteinases (MMPs) of human intervertebral disc degeneration tissues were measured by real-time quantitative PCR, and a correlation between the expression level of HtrA1 and MMPs was also investigated. Human nucleus pulposus cells (HNPCs) were challenged with rHtrA1, and expression of MMPs was measured by real-time quantitative PCR, Western blotting, and ELISA. Moreover, to analyze the mechanism by which HtrA1 up-regulates MMPs, ERK1/2/ROCK signaling pathway inhibitors were also used. RESULTS: We found significant increases in mRNA expression of HtrA1 and MMP1, 3, 9, and 13 in IDD tissues compared with control. HtrA1 expression level was associated with the levels of MMP1, 3, and 13. Expression of MMP1, 3, and 13 mRNA and protein were significantly increased in HNPCs treated by rHtrA1. Moreover, administration of the ERK1/2 signaling pathway inhibitor or ROCK signaling pathway inhibitor decreased rHtrA1-induced MMPs production. Therefore, changes in HtrA1 expression could be involved in the pathogenesis of IDD. CONCLUSION: Our findings indicate that HtrA1 can induce increases in MMPs in HNPCs via the ERK1/2/ROCK signaling pathway, thus providing new insights into the role of HtrA1 in the pathogenesis of IDD.

Enhanced circulating ILC2s and MDSCs may contribute to ensure maintenance of Th2 predominant in patients with lung cancer.

Group 2 innate lymphoid cells (ILC2s) were demonstrated to be involved in the initiation and coordination of type 2 T helper cell (Th2) responses. Myeloid­derived suppressor cells (MDSCs) have received a great deal of attention for their role in creating an immunosuppressive microenvironment in cancer­bearing hosts. However, the contributions of ILC2s in the occurrence and development of lung cancer, and the association between ILC2s and Th2 or MDSCs in lung cancer remain to be elucidated. In the present study, 36 patients newly diagnosed with lung cancer based on the guidelines of the International Union Against Cancer Tumor Node Metastasis were included. The frequencies of ILC2s and MDSCs in peripheral blood mononuclear cells were determined, and the mRNA expression levels of ILC2s or Th2­related transcription factors and cytokines, and MDSCs­related products were assessed. The results demonstrated that the frequencies of the circulatory ILC2s and MDSCs were enhanced in lung cancer patients, as were ILC2­related transcription factors and cytokines in peripheral blood. A positive correlation was identified between the Th2­dominated phenotype and the expression levels of ILC2s­associated cytokines or transcription factors. In addition, increased autophagy related 1 was closely associated with Th2­associated transcription factors. It was demonstrated that ILC2s and MDSCs were clearly upregulated and accompanied by a predominant Th2 phenotype in patients with lung cancer; this may lead to new immunotherapy approaches for lung cancer based on the associated metabolites and cytokines.

Myeloid-derived suppressor cells and myeloid regulatory cells in cancer and autoimmune disorders.

Myeloid-derived suppressor cells (MDSCs) were originally described as a heterogeneous population of immature cells derived from myeloid progenitors with immune-suppressive functions in tumor-bearing hosts. In recent years, increasing number of studies have described various populations of myeloid cells with MDSC-like properties in murine models of cancer and autoimmune diseases. These studies have observed that the populations of MDSCs are increased during inflammation and autoimmune conditions. In addition, MDSCs can effectively suppress T cell responses and modulate the activity of natural killer cells and other myeloid cells. MDSCs have also been implicated in the induction of regulatory T cell production. Furthermore, these cells have the potential to suppress the autoimmune response, thereby limiting tissue injury. Myeloid regulatory cells (Mregs) are recently attracting increasing attention, since they function in proinflammatory and immune suppression in autoimmune diseases, as well as in various types of cancer. Currently, research focus is directed from MDSCs to Mregs in cancer and autoimmune diseases. The present study reviewed the suppressive roles of MDSCs in various autoimmune murine models, the immune modulation of MDSCs to T helper 17 lymphocytes, as well as the proinflammatory and immunosuppressive roles of Mregs in various types of cancer and autoimmune diseases.

IL-17B activated mesenchymal stem cells enhance proliferation and migration of gastric cancer cells.

Mesenchymal stem cells are important cells in tumor microenvironment. We have previously demonstrated that IL-17B/IL-17RB signal promoted progression of gastric cancer. In this study, we further explored the effect of IL-17B on mesenchymal stem cells in tumor microenvironment and its impact on the tumor progression. The results showed that IL-17B induced the expression of stemness-related genes Nanog, Sox2, and Oct4 in mesenchymal stem cells and enhanced its tumor-promoting effect. The supernatant from cultured mesenchymal stem cells after treating with exogenous rIL-17B promoted the proliferation and migration of MGC-803, therefor suggesting that rIL-17B might promote mesenchymal stem cells to produce soluble factors. In addition, rIL-17B also activated the NF-κΒ, STAT3, ß-catenin pathway in mesenchymal stem cells. Our data revealed a new mechanism that IL-17B enhanced the progression of gastric cancer by activating mesenchymal stem cells.

Characterization and distribution of drug resistance associated ß-lactamase, membrane porin and efflux pump genes in MDR A. baumannii isolated from Zhenjiang, China.

BACKGROUND: Acinetobacter baumannii (A. baumannii), especially the multidrug resistant A. baumannii (MDR-AB) is becoming a common opportunistic pathogen in hospital, and constitutes significant public health threats. This study aimed at investigating the relationship between drug resistance with expression of class A-D ß-lactamase genes, mutation in membrane porin and over-expression of efflux pump genes among A. baumannii isolated from Zhengjiang, China. METHODS: Antibiotic susceptibility assays were performed using Kirby-Bauer disc diffusion method. PCR was used to detect ß-lactamase genes and carO, oprD, adeR, adeS. Real-time PCR was used to assess the mRNA expression level of efflux pump gene adeB. The software of DNAMAN was applied to assemble oprD and carO sequences, and the sequences were compared with those retrieved from GenBank (http://www.ncbi.nlm.nih.gov/). RESULTS: 27 isolates (61.4%) in this study were MDR-AB, in which five ß-lactamases including TEM, CTX-M-2, ADC, OXA-23 and OXA-51 were found, and the positive rate was 96.3% (26), 14.8% (4), 92.6% (25), 88.9% (24) and 92.6% (25), respectively. In addition, the expression level of adeB mRNA was significantly increased in MDR-AB, it might due to adeR mutation. Some mutations were also found in carO and oprD. CONCLUSION: MDR-AB showed high relationship with ß-lactamase, mutation in membrane porin and overexpression of adeB, which may directly relates to the mutation in regulating gene adeR.

Downregulation of Runx3 is closely related to the decreased Th1-associated factors in patients with gastric carcinoma.

Runt-related transcription factor 3 (Runx3) is a tumor-suppressor gene and plays an important role in immune regulation, whose reduced expression may play an important role in the development and progression of gastric carcinoma. The aim of this study was to investigate the role of Runx3 on the levels of transcription factors in patients with gastric carcinoma and analyze the relationship between the expression of Runx3 and Th1-type cytokines in peripheral blood mononuclear cells (PBMCs). Our results showed that the expression levels of Runx3, T-bet, and IFN-γ in patients with gastric carcinoma were obviously lower than those in control groups, and there was a positive correlation between the expression of Runx3 and T-bet or IFN-γ in patients (p < 0.01). In order to further confirm this result, the Runx3 gene was constructed into pIRES2-eGFP and the recombined plasmid was transfected into SGC-7901 cells with liposome in vitro, the results obtained from the reverse transcription PCR indicated that the mRNA of Runx3, T-bet, or IFN-γ was significantly upregulated individually in Runx3 gene-transfected SGC-7901 cells. It suggested that the Runx3 and Th1-associated factors including T-bet and IFN-γ synchronization declines in gastric carcinoma may contribute to the development of cancer.

The expression of Toll-like receptor 8 and its relationship with VEGF and Bcl-2 in cervical cancer.

BACKGROUND: Cervical cancer is one of the most common cancers in women worldwide, often associated with the infection of human papillomavirus (HPV). Toll-like receptor 8 (TLR8), a pattern recognition receptor, is involved in viral nucleic acid sensing. Recently TLR8 has been shown to be expressed in cancer cells, and it has been suggested that it may help cancer cell growth and tumor development. The objective of this study is to investigate the expression of TLR8 expression and its relationship with Bcl-2 and VEGF in cervical cancer cells. METHODOLOGY/PRINCIPAL: The mRNA expression levels of Bcl-2, VEGF and TLR-7,-8,-9 in newly diagnosed cervical cancer patients were detected by quantitative real-time PCR (qRT- PCR). Epifluorescence microscope was used to determine the presence of TLR8 protein in Hela cells. The cell cycle and apoptosis were analyzed by flow cytometer, and the cell proliferation was measured by MTT assay. Our data showed the increased mRNA levels of TLR8 in human cervical cancer samples as well as in HeLa cells, a cell line derived from a human cervical cancer. In addition, there was a positive correlation between the expression levels of TLR8 and Bcl-2 and VEGF in cervical cancer patients. When Hela cells were treated with TLR8 agonist CL075, the percentage of cells in G2/M +S was remarkably increased, accompanied by increased COX-2, BCL-2 and VEGF mRNA levels. CONCLUSIONS/SIGNIFICANCE: The mRNA expression level of TLR8 in the patients with cervical cancer and Hela cells were up-regulated, it consistent with the increased expression of VEGF and Bcl-2. The results suggest that TLR8 may be an interesting therapeutic target in cervical cancer.

CpG-oligodeoxynucleotides suppress the proliferation of A549 lung adenocarcinoma cells via toll-like receptor 9 signaling and upregulation of Runt-related transcription factor 3 expression.

The aim of the present study was to investigate the effect of CpG-oligodeoxynucelotides (CpG-ODN) on the proliferation of the A549 human lung adenocarcinoma cell line and the expression of Runt-related transcription factor 3 (Runx3) and investigate the association between the toll-like receptor 9 (TLR9) signaling pathway and Runx3 expression during A549 cell proliferation. Different concentrations of CpG-ODN were used in this study to stimulate A549 cells and the expression of Runx3 at the mRNA or protein level was detected by reverse transcription-polymerase chain reaction or western blot analysis. Moreover, Runx3 siRNA was synthesized and transiently transfected into the A549 cells and the MTT assay was used to detect the effects of CpG-ODN on transfected cell growth. Our data demonstrated that CpG-ODN significantly inhibited the proliferation of A549 cells. The expression of Runx3 in the mRNA and protein level was increased in A549 cells stimulated by CpG-ODN. The CpG-ODN-stimulated cell proliferation was significantly inhibited in Runx3 siRNA-transfected A549 cells. In conclusion, CpG-ODN may bind to TLR9, inhibit the proliferation of A549 cells and upregulate the expression of Runx3.