Accumulating evidence has suggested that farnesoid X receptor (FXR) agonists, such as obeticholic acid (OCA) are therapeutically useful for non-alcoholic steatohepatitis (NASH). However, it is still ...unclear how FXR agonists protect against NASH and which cell type is the main target of FXR agonists. In this study, we examined the effects of OCA on the development of NASH using melanocortin 4 receptor-deficient (MC4R-KO) mice that progressively developed hepatic steatosis and NASH on Western diet (WD). Treatment with OCA effectively prevented chronic inflammation and liver fibrosis in WD-fed MC4R-KO mice with only marginal effect on body weight and hepatic steatosis. Hepatic crown-like structure (hCLS) is a unique histological structure characteristic of NASH, which triggers hepatocyte death-induced interstitial fibrosis. Intriguingly, treatment with OCA markedly reduced hCLS formation even after MC4R-KO mice developed NASH, thereby inhibiting the progression of liver fibrosis. As its mechanism of action, OCA suppressed metabolic stress-induced p53 activation and cell death in hepatocytes. Our findings in this study highlight the role of FXR in hepatocytes in the pathogenesis of NASH. Collectively, this study demonstrates the anti-fibrotic effect of OCA in a murine model of NASH with obesity and insulin resistance, which suggests the clinical implication for human NASH.
Background
Recently we reported novel noninvasive scoring systems for diagnosing nonalcoholic steatohepatitis (NASH) and related fibrosis, namely FM-NASH index and FM-fibro index. They are highly ...accurate, however, they contain some items not widely used in clinical practice and require six or more items to diagnose both NASH and related fibrosis. By focusing on widely used items, we tried to identify convenient markers in common with the both diagnoses.
Methods
To explore the markers for NASH and related fibrosis in nonalcoholic fatty liver disease (NAFLD) patients, we used data of 24 clinical items in our previous report. By logistic regression analysis, we identified items suitable for the both diagnoses. We then evaluated their accuracies by area under the receiver operator characteristic curves (AUROCs) on independent validation data.
Results
We identified the combination of type IV collagen 7S and aspartate aminotransferase (AST) as the predictor both for NASH and related fibrosis. We developed a scoring system based on the combination and evaluated the prediction accuracy: the AUROCs for training/validation data sets are 0.857/0.769 for NASH and 0.918/0.842 for NASH-related fibrosis. The former was higher than that of NAFIC score, and the latter was higher than those of existing fibrosis markers: BARD score, FIB-4 index and NAFLD fibrosis score but lower than FM-fibro index.
Conclusions
The scoring system using type IV collagen 7S and AST named CA index can predict both NASH and related fibrosis in NAFLD patients with sufficient accuracy and could be a convenient diagnostic and screening tool for NASH and related fibrosis. The scoring system needs to be validated in independent larger populations from multiple clinical centers.
The consumption of fructose, including the use of high‐fructose corn syrup as a sweetener, has increased continuously in recent decades. Although the involvement of fructose in the development of ...metabolic diseases has been emphasized recently, whether fructose intake increases susceptibility to steatosis‐associated hepatocellular carcinoma (HCC) is unclear. Here, we investigated this issue using mice lacking a circulating protein, apoptosis inhibitor of macrophage (AIM, encoded by cd5l). AIM does not induce carcinogenesis of hepatocytes, but provokes necrotic death specifically in AIM‐bound cancer cells through complement cascade activation, thereby preventing HCC tumor development in wild‐type mice. When subjected to a high‐fructose diet (HFrD), AIM‐deficient (AIM–/–) mice showed liver steatosis and subsequent liver inflammation as well as fibrosis, but at much milder levels compared with mice fed a high‐fat diet. However, AIM–/– mice were markedly susceptible to HCC tumor development, whereas no wild‐type mice developed the disease. Systemic metabolic states, including obesity and insulin resistance, were similar in both types of mice after HFrD challenge, indicating no influence of AIM on HFrD‐induced metabolic changes. Our results suggest that dietary fructose increases the risk for liver carcinogenesis and that individuals with low blood AIM levels may be susceptible to HCC under chronic fructose intake.
In this study, by using mice lacking apoptosis inhibitor of macrophage (AIM) protein, we found that dietary fructose highly increases the risk for liver carcinogenesis. Our results might alert people to the risk of dietary fructose, in particular, in terms of liver carcinogenesis.
Owing to rapid and drastic changes in lifestyle and eating habits in modern society, obesity and obesity-associated diseases are among the most important public health problems. Hence, the ...development of therapeutic approaches to regulate obesity is strongly desired. In view of previous work showing that apoptosis inhibitor of macrophage (AIM) blocks lipid storage in adipocytes, thereby preventing obesity caused by a high-fat diet, we here explored a strategy to augment circulating AIM levels. We synthesized the Fc portion of the soluble human immunoglobulin (Ig)M heavy chain and found that it formed a pentamer containing IgJ as natural IgM does, and effectively associated with AIM in vitro. When we injected the synthesized Fc intravenously into mice lacking circulating IgM, it associated with endogenous mouse AIM, protecting AIM from renal excretion and preserving the circulating AIM levels. As the synthesized Fc lacked the antigen-recognizing variable region, it provoked no undesired immune response. In addition, a challenge with the Fc-human AIM complex in wild-type mice, which exhibited normal levels of circulating IgM and AIM, successfully maintained the levels of the human AIM in mouse blood. We also observed that the human AIM was effectively incorporated into adipocytes in visceral fat tissue, suggesting its functionality against obesity. Thus, our findings reveal potent strategies to safely increase AIM levels, which could form the basis for developing novel therapies for obesity.
Background: Neoadjuvant endocrine therapy is not the standard of care for breast cancer, primarily because the optimal treatment duration remains unclear. This phase 2 prospective multicenter study ...analyzed time to progression, time to maximal response, and time to treatment failure for neoadjuvant exemestane. Methods: Inclusion criteria were women aged ≥60 years with Stage II or III breast cancer classified as estrogen receptor-positive/human epidermal growth factor receptor 2-negative. Response was defined as a ≥10% and minimum of 3 mm decrease in tumor size, as compared with the most recent or smallest value, and no new lesion. Progression was defined as a >10% and minimum of over 3 mm increase in tumor size, as compared with the most recent or smallest value, or a new lesion. Maximal response was defined as the final recorded response. Results: This study included 24 women, most of whom had T2 N0 tumors with high estrogen receptor expression. We initially observed a response in 23 patients (96%); however, 6 patients (25%) later experienced progression. Time to progression, time to maximal response, and time to treatment failure ranged from 7 to 22 months (estimated median, 35), 1 to 22 months (estimated median, 10), and 2 to 22 months (estimated median, 22), respectively. Treatment duration varied widely, but the estimated optimal duration of neoadjuvant exemestane therapy was 22 to 35 months in patients seeking to avoid surgery and 10 months in patients wishing to receive breast-conserving surgery. Conclusions: Neoadjuvant exemestane therapy is long effective for older women with hormone-sensitive breast cancer.
Targeting tumor angiogenesis is an established strategy for cancer therapy. Because angiogenesis is not limited to pathological conditions such as cancer, molecular markers that can distinguish ...between physiological and pathological angiogenesis are required to develop more effective and safer approaches for cancer treatment. To identify such molecules, we determined the gene expression profiles of murine tumor endothelial cells (mTEC) and murine normal endothelial cells using DNA microarray analysis followed by quantitative reverse transcription–polymerase chain reaction analysis. We identified 131 genes that were differentially upregulated in mTEC. Functional analysis using siRNA‐mediated gene silencing revealed five novel tumor endothelial cell markers that were involved in the proliferation or migration of mTEC. The expression of DEF6 and TMEM176B was upregulated in tumor vessels of human renal cell carcinoma specimens, suggesting that they are potential targets for antiangiogenic intervention for renal cell carcinoma. Comparative gene expression analysis revealed molecular differences between tumor endothelial cells and normal endothelial cells and identified novel tumor endothelial cell markers that may be exploited to target tumor angiogenesis for cancer treatment.
We identified 131 genes that were differentially upregulated in mTECs. Functional analysis using siRNA‐mediated gene silencing revealed five novel TEC markers that were involved in the proliferation or migration of mTECs. The expression of DEF6 and TMEM176B was upregulated in tumor vessels of human renal cell carcinoma (RCC) specimens, suggesting that they are potential targets for antiangiogenic intervention for RCC.
Hepatocellular carcinoma (HCC) is a widespread fatal disease and the third most common cause of cancer deaths. Here, we show the potent anti-HCC effect of the circulating protein AIM. As in ...adipocytes, AIM is incorporated into normal hepatocytes, where it interferes with lipid storage. In contrast, AIM accumulates on the HCC cell surface and activates the complement cascade via inactivating multiple regulators of complement activation. This response provokes necrotic cell death specifically in AIM-bound HCC cells. Accordingly, AIM(-/-) mice were highly susceptible to steatosis-associated HCC development, whereas no AIM(+/+) mouse developed the disease despite comparable liver inflammation and fibrosis in response to a long-term high-fat diet. Administration of AIM prevented tumor development in AIM(-/-) mice, and HCC induction by diethylnitrosamine was more prominent in AIM(-/-) than wild-type mice. These findings could be the basis for novel AIM-based therapeutic strategies for HCC.
Abstract Macrolides have been reported to exert a variety of effects on both host immunomodulation and repression of bacterial pathogenicity. In this study, we report that the 3′,5′-cyclic diguanylic ...acid (c-di-GMP) signaling system, which regulates virulence in Pseudomonas aeruginosa , is affected by the macrolide azithromycin. Using DNA microarray analysis, we selected a gene encoding PA2567 related to c-di-GMP metabolism that was significantly affected by azithromycin treatment. Expression of the PA2567 gene was significantly repressed by azithromycin in a time- and dose-dependent manner, whereas no difference in PA2567 gene expression was observed in the absence of azithromycin. In-frame deletion of the PA2567 gene affected both virulence factors and the quorum-sensing system, and significantly decreased total bacteria in a mouse pneumonia model compared to the wild-type strain ( P < 0.05). These results suggest that macrolides possess the ability to modulate c-di-GMP intracellular signaling in P. aeruginosa.
Natural immunoglobulin M (IgM) is reactive to autoantigens and is believed to be important for autoimmunity. Blood pentameric IgM loaded with antigens forms a large immune complex (IC) that contains ...various elements, including apoptosis inhibitor of macrophage (AIM). Here we demonstrate that this IgM-AIM association contributes to autoantibody production under obese conditions. In mice fed a high-fat diet, natural IgM increased through B cell TLR4 stimulation. AIM associated with IgM and protected AIM from renal excretion, increasing blood AIM levels along with the obesity-induced IgM augmentation. Meanwhile, the AIM association inhibited IgM binding to the Fcα/μ receptor on splenic follicular dendritic cells, thereby protecting the IgM IC from Fcα/μ receptor-mediated internalization. This supported IgM-dependent autoantigen presentation to B cells, stimulating IgG autoantibody production. Accordingly, in obese AIM-deficient (AIM−/−) mice, the increase of multiple IgG autoantibodies observed in obese wild-type mice was abrogated. Thus, the AIM-IgM association plays a critical role in the obesity-associated autoimmune process.
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► AIM is protected from renal excretion via binding to IgM pentamers in blood ► Association with AIM interferes with Fcα/μ receptor-mediated internalization of IgM ► IgM-dependent autoantigen presentation on FDCs is preserved by AIM ► Absence of AIM tempers obesity-associated multiple IgG autoantibody production
In addition to inducing metabolic and cardiovascular diseases, obesity also increases blood immunoglobulin M (IgM) levels, followed by multiple autoantibody expansion leading to autoimmune disease. Here, Arai, Miyazaki, and colleagues show that apoptosis inhibitor of macrophage (AIM) associates with IgM and abrogates IgM internalization through the Fcα/μ receptor. This response supports IgM-dependent autoantigen presentation to B cells on splenic follicular dendritic cells, thereby enhancing the development of high-affinity IgG autoantibody-producing plasma cells. Thus, AIM suppression may be a promising candidate for the next generation of therapy for preventing obesity-associated autoimmune diseases.
Hepatocellular carcinoma (HCC), the fifth most common cancer type and the third highest cause of cancer death worldwide, develops in different types of liver injuries, and is mostly associated with ...cirrhosis. However, non-alcoholic fatty liver disease often causes HCC with less fibrosis, and the number of patients with this disease is rapidly increasing. The high mortality rate and the pathological complexity of liver diseases and HCC require blood biomarkers that accurately reflect the state of liver damage and presence of HCC.
Here we demonstrate that a circulating protein, apoptosis inhibitor of macrophage (AIM) may meet this requirement. A large-scale analysis of healthy individuals across a wide age range revealed a mean blood AIM of 4.99 ± 1.8 µg/ml in men and 6.06 ± 2.1 µg/ml in women. AIM levels were significantly augmented in the younger generation (20s-40s), particularly in women. Interestingly, AIM levels were markedly higher in patients with advanced liver damage, regardless of disease type, and correlated significantly with multiple parameters representing liver function. In mice, AIM levels increased in response to carbon tetrachloride, confirming that the high AIM observed in humans is the result of liver damage. In addition, carbon tetrachloride caused comparable states of liver damage in AIM-deficient and wild-type mice, indicating no influence of AIM levels on liver injury progression. Intriguingly, certain combinations of AIM indexes normalized to liver marker score significantly distinguished HCC patients from non-HCC patients and thus could be applicable for HCC diagnosis.
AIM potently reveals both liver damage and HCC. Thus, our results may provide the basis for novel diagnostic strategies for this widespread and fatal disease.
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