Background-Macrophage activation plays a crucial role in regulating adipose tissue inflammation and is a major contributor to the pathogenesis of obesity-associated cardiovascular diseases. On various types of stimuli, macrophages respond with either classic (M1) or alternative (M2) activation. M1-and M2-mediated signaling pathways and corresponding cytokine production profiles are not completely understood. The discovery of microRNAs provides a new opportunity to understand this complicated but crucial network for macrophage activation and adipose tissue function. Methods and Results-We have examined the activity of microRNA-223 (miR-223) and its role in controlling macrophage functions in adipose tissue inflammation and systemic insulin resistance. miR-223 Ϫ/Ϫ mice on a high-fat diet exhibited an increased severity of systemic insulin resistance compared with wild-type mice that was accompanied by a marked increase in adipose tissue inflammation. The specific regulatory effects of miR-223 in myeloid cell-mediated regulation of adipose tissue inflammation and insulin resistance were then confirmed by transplantation analysis. Moreover, using bone marrow-derived macrophages, we demonstrated that miR-223 is a novel regulator of macrophage polarization, which suppresses classic proinflammatory pathways and enhances the alternative antiinflammatory responses. In addition, we identified Pknox1 as a genuine miR-223 target gene and an essential regulator for macrophage polarization. Conclusion-For the first time, this study demonstrates that miR-223 acts to inhibit Pknox1, suppressing proinflammatory activation of macrophages; thus, it is a crucial regulator of macrophage polarization and protects against diet-induced adipose tissue inflammatory response and systemic insulin resistance. (Circulation. 2012;125:2892-2903.)Key Words: adipose tissue Ⅲ insulin resistance Ⅲ macrophages Ⅲ microRNAs A dipose tissue inflammation is a hallmark of obesity and a causal factor of metabolic disorders such as insulin resistance 1-5 and a wide variety of metabolic diseases, including atherosclerosis and type 2 diabetes mellitus. 4 -6 Mice fed a high-fat diet (HFD) frequently develop chronic low-grade inflammation within adipose tissues, characterized by increased infiltration of immune cells and the production of proinflammatory cytokines. 1,2 Consequently, adipocytes produce a number of inflammatory mediators that contribute to atherosclerotic cardiovascular disease. 7,8 Importantly, elevated adipose tissue inflammation is a significant factor contributing to systemic insulin resistance, 9 -14 which is an additional risk factor for cardiovascular disease through both inflammation-dependent and -independent mechanisms. Given the importance of adipose tissue inflammation in metabolic diseases, there is a critical need to better understand the mechanisms underlying these inflammatory processes. Editorial see p 2815 Clinical Perspective on p 2903Several reports demonstrate that macrophages are key regulators of adipose tissue inflammat...
Cancer-associated mesenchymal stem cells (MSCs) play a pivotal role in modulating tumor progression. However, the interactions between liver cancer-associated MSCs (LC-MSCs) and hepatocellular carcinoma (HCC) remain unreported. Here, we identified the presence of MSCs in HCC tissues. We also showed that LC-MSCs significantly enhanced tumor growth in vivo and promoted tumor sphere formation in vitro. LC-MSCs also promoted HCC metastasis in an orthotopic liver transplantation model. Complementary DNA (cDNA) microarray analysis showed that S100A4 expression was significantly higher in LC-MSCs compared with liver normal MSCs (LN-MSCs) from adjacent cancer-free tissues. Importantly, the inhibition of S100A4 led to a reduction of proliferation and invasion of HCC cells, while exogenous S100A4 expression in HCC cells resulted in heavier tumors and more metastasis sites. Our results indicate that S100A4 secreted from LC-MSCs can promote HCC cell proliferation and invasion. We then found the expression of oncogenic micro-RNA (miR)-155 in HCC cells was significantly up-regulated by coculture with LCMSCs and by S100A4 ectopic overexpression. The invasion-promoting effects of S100A4 were significantly attenuated by a miR-155 inhibitor. These results suggest that S100A4 exerts its effects through the regulation of miR-155 expression in HCC cells. We demonstrate that S100A4 secreted from LC-MSCs promotes the expression of miR-155, which mediates the down-regulation of suppressor of cytokine signaling 1, leading to the subsequent activation of STAT3 signaling. This promotes the expression of matrix metalloproteinases 9, which results in increased tumor invasiveness. Conclusion: S100A4 secreted from LC-MSCs is involved in the modulation of HCC progression, and may be a potential therapeutic target. (HEPATOLOGY 2013;57:2274-2286 T he tumor microenvironment plays an important role in modulating cancer and cancer stem cell progression. 1,2 Recently, mesenchymal stem cells (MSCs), as a pivotal part of the tumor stroma, have attracted great attention for their ability to participate in tumor proliferation 3 and metastasis. 4 Although several lines of evidence demonstrate that MSCs can be activated by cancer cells and contribute to tumor progression, the Abbreviations:: cDNA, complementary DNA; ELISA, enzyme-linked immunosorbent assay; HCC, hepatocellular carcinoma; IHC, immunohistochemistry; LCMSCs, liver cancer-associated MSCs; LN-MSCs, liver normal MSCs; miRNA, microRNA; miR-155, microRNA-155; MMP9, matrix metalloproteinases 9; MSCs, mesenchymal stem cells; qRT-PCR, quantitative real time polymerase chain reaction; siRNA, small interfering RNA; SOCS1, suppressor of cytokine signaling 1; STAT, signal transducer and activator of transcription.From the
c‐Jun N‐terminal kinase (JNK) is involved in cancer cell apoptosis; however, emerging evidence indicates that this Janus signaling promotes cancer cell survival. JNK acts synergistically with NF‐κB, JAK/STAT, and other signaling molecules to exert a survival function. JNK positively regulates autophagy to counteract apoptosis, and its effect on autophagy is related to the development of chemotherapeutic resistance. The prosurvival effect of JNK may involve an immune evasion mechanism mediated by transforming growth factor‐β, toll‐like receptors, interferon‐γ, and autophagy, as well as compensatory JNK‐dependent cell proliferation. The present review focuses on recent advances in understanding the prosurvival function of JNK and its role in tumor development and chemoresistance, including a comprehensive analysis of the molecular mechanisms underlying JNK‐mediated cancer cell survival. There is a focus on the specific “Yin and Yang” functions of JNK1 and JNK2 in the regulation of cancer cell survival. We highlight recent advances in our knowledge of the roles of JNK in cancer cell survival, which may provide insight into the distinct functions of JNK in cancer and its potential for cancer therapy.
AIM:To explore the possible mechanism of intrauterine infection of hepatitis B virus (HBV). METHODS:HBV DNA was detected in vaginal secretion and amniotic fluid from 59 HBsAg-positive mothers and in venous blood of their newborns by PCR. HBsAg and HBcAg in placenta were determined by ABC immunohistochemistry. RESULTS:The rate of HBV intrauterine infection was 40.1% (24/59). HBV DNA was detected in 47.5% of amniotic fluid samples and 52.5% of vaginal secretion samples respectively. HBsAg and HBcAg were detected in placentas from HBsAgpositive mothers. The concentration of the two antigens decreased from the mother's side to the fetus's side, in the following order: maternal decidual cells > trophoblastic cells > villous mesenchymal cells > villous capillary endothelial cells. However, in 4 placentas the distribution was in the reverse order. HBsAg and HBcAg were detected in amniotic epithelial cells from 32 mothers. CONCLUSION:The main route of HBV transmission from mother to fetus is transplacental, from the mother side of placenta to the fetus side. However, HBV intrauterine infection may take place through other routes.
Vibrio mimicus differs from Vibrio cholerae in a number of genotypic and phenotypic traits but like V. cholerae can give rise to diarrheal disease. We examined clinical isolates of V. mimicus for the presence of CTX⌽, the lysogenic filamentous bacteriophage that carries the cholera toxin genes in epidemic V. cholerae strains. Four V. mimicus isolates were found to contain complete copies of CTX⌽. Southern blot analyses revealed that V. mimicus strain PT5 contains two CTX prophages integrated at different sites within the V. mimicus genome whereas V. mimicus strains PT48, 523-80, and 9583 each contain tandemly arranged copies of CTX⌽. We detected the replicative form of CTX⌽, pCTX, in all four of these V. mimicus isolates. The CTX prophage in strain PT5 was found to produce infectious CTX⌽ particles. The nucleotide sequences of CTX⌽ genes orfU and zot from V. mimicus strain PT5 and V. cholerae strain N16961 were identical, indicating contemporary horizontal transfer of CTX⌽ between these two species. The receptor for CTX⌽, the toxin-coregulated pilus, which is encoded by another lysogenic filamentous bacteriophage, VPI⌽, was also present in the CTX⌽-positive V. mimicus isolates. The nucleotide sequences of VPI⌽ genes aldA and toxT from V. mimicus strain PT5 and V. cholerae N16961 were identical, suggesting recent horizontal transfer of this phage between V. mimicus and V. cholerae. In V. mimicus, the vibrio pathogenicity island prophage was integrated in the same chromosomal attachment site as in V. cholerae. These results suggest that V. mimicus may be a significant reservoir for both CTX⌽ and VPI⌽ and may play an important role in the emergence of new toxigenic V. cholerae isolates.Cholera toxin (CT) is encoded by the ctxAB operon, which resides in the genome of CTX⌽, a filamentous bacteriophage that specifically infects Vibrio cholerae (40). CTX⌽ is found in all epidemic V. cholerae isolates but is rarely recovered from non-O1/non-O139 V. cholerae environmental isolates (12). The CTX⌽ genome can integrate into the V. cholerae genome to form a stable prophage or it can replicate as a plasmid in isolates lacking an appropriate integration site. Of the nearly 200 recognized serogroups of V. cholerae only the O1 and O139 serogroups are associated with epidemics of cholera (2). In classical biotype strains of V. cholerae serogroup O1 there is a CTX prophage on each of the two V. cholerae chromosomes (24, 38), whereas in El Tor biotype strains of V. cholerae serogroup O1 the CTX prophages are tandemly arranged on the larger of the two chromosomes (26,30). CTX⌽ has a 6.9-kb genome made up of two functionally diverse regions: the core and RS2 regions. The core region encodes CT and contains the genes involved in phage morphogenesis, including genes that are thought to encode the major and minor phage coat proteins and a protein required for CTX⌽ assembly (40). The RS2 region contains genes required for replication, integration, and regulation of CTX⌽ (20, 43). In El Tor V. cholerae isolates, the CTX prophage genome is...
A secreted phosphodiesterase/aIkaline phosphatase, APaseD, was purified from a culture of Bacillus subfilis JH646MS. Its phosphodiesterase activity was reminiscent of an APase isolated and characterized previously. lmmunoassay and N-terminal sequencing showed the two proteins to be identical. Using the first 20 amino acids of the mature protein, a BLAST search of GenBank was used to find an homologous sequence. An exact match was found but in a putative non-coding region. It was hypothesized that there was a base pair deletion in the phoD gene. A DNA fragment internal to the coding region was generated by PCR using template DNA from a strain which produced APaseD. The PCR fragment was cloned and used to interrupt the gene. Western blot analysis of the parent and the mutated strains showed that APaseD was missing in the mutant. Resequencing of the gene revealed a larger ORF encoding a protein similar in size to the 49 kDa APaseD estimated by SDS-PAGE. The promoter was then cloned, sequenced and used in phoD-lacZ promoter fusions which showed that the gene was phosphate-starvation-induced and dependent on PhoP and PhoR for expression.
Rationale: Endothelial cells in situ are largely quiescent, and their isolation and culture are associated with the switch to a proliferative phenotype. Objective: To identify antiangiogenic microRNAs expressed by native endothelial cells that are altered after isolation and culture, as well as the protein targets that regulate responses to growth factors. Methods and Results: Profiling studies revealed that miR-223 was highly expressed in freshly isolated human, murine, and porcine endothelial cells, but those levels decreased in culture. In primary cultures of endothelial cells, vascular endothelial cell growth factor and basic fibroblast growth factor further decreased miR-223 expression. The overexpression of precursor-miR-223 did not affect basal endothelial cell proliferation but abrogated vascular endothelial cell growth factor–induced and basic fibroblast growth factor–induced proliferation, as well as migration and sprouting. Inhibition of miR-223 in vivo using specific antagomirs potentiated postnatal retinal angiogenesis in wild-type mice, whereas recovery of perfusion after femoral artery ligation and endothelial sprouting from aortic rings from adult miR-223 −/y animals were enhanced. MiR-223 overexpression had no effect on the growth factor–induced activation of ERK1/2 but inhibited the vascular endothelial cell growth factor–induced and basic fibroblast growth factor–induced phosphorylation of their receptors and activation of Akt. β1 integrin was identified as a target of miR-223 and its downregulation reproduced the defects in growth factor receptor phosphorylation and Akt signaling seen after miR-223 overexpression. Reintroduction of β1 integrin into miR-223–ovexpressing cells was sufficient to rescue growth factor signaling and angiogenesis. Conclusions: These results indicate that miR-223 is an antiangiogenic microRNA that prevents endothelial cell proliferation at least partly by targeting β1 integrin.
Thus, calpain inhibition may be one means of normalizing platelet miRNA processing as well as platelet function in diabetes mellitus.
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