Maternal exposure to soy diet reduces atheroma in hyperlipidemic F1 offspring mice by promoting macrophage and T cell anti-inflammatory responses.

BACKGROUND AND AIMS: Maternal hypercholesterolemia has been implicated in earlier onset of atherosclerotic lesions in neonatal offspring. In this study, we investigated whether maternal exposure to soy protein isolate (SPI) diet attenuated the progression of atherosclerosis in F1 offspring. METHOD: Pregnant apolipoprotein E knockout (Apoe-/-) female mice were fed SPI diet until postnatal day 21 (PND21) of the offspring (SPI-offspring). SPI-offspring were switched at PND21 to casein (CAS) diet until PND140. Mice fed CAS throughout their lifetime (gestation to adulthood) were used as controls (CAS-offspring). RESULTS: Atherosclerotic lesions in the aortic sinuses were reduced in SPI-offspring compared with CAS-offspring. Total serum cholesterol levels in CAS-offspring or dams were comparable to levels in their SPI-counterparts, suggesting that alternative mechanisms contributed to the athero-protective effect of maternal SPI diet. Aortic VCAM-1, MCP-1, and TNF-α mRNA and protein expression, and expression of macrophage pro-inflammatory cytokines was reduced in SPI-offspring. Interestingly, CD4+ T cells from SPI-offspring showed reduced IFN-γ expression (Th1), while the expression of IL-10 (Th2/Treg), and IL-13 (Th2) was increased. DNA methylation analyses revealed that anti-inflammatory T cell-associated Gata3 and Il13 promoter regions were hypomethylated in SPI-offspring. These findings suggest that anti-inflammatory macrophage and T cell response may have contributed to the athero-protective effect in SPI-offspring. CONCLUSIONS: Our findings demonstrate that gestational and lactational soy diet exposure inhibits susceptibility to atherosclerotic lesion formation by promoting anti-inflammatory responses by macrophages and T cells.

Overexpression of COX7RP promotes tumor growth and metastasis by inducing ROS production in hepatocellular carcinoma cells.

Cumulative evidence has indicated that mitochondrial respiration dysfunction plays important roles in tumorigenesis. However, the role of COX7RP, a critical regulator in the formation of mitochondrial respiratory supercomplex that has been suggested to be over-expressed in hepatocellular carcinoma (HCC) by our bioinformatic analysis of TCGA data, in tumor progression remains largely unclear. In this study, we found that COX7RP is frequently over-expressed in HCC mainly due to the down-regulation of miR-130a-3p and predicts poor prognosis of HCC patients. Functional experiments revealed that COX7RP promoted both growth and metastasis of HCC through induction of cell cycle progression and epithelial to mesenchymal transition (EMT), and suppression of cell apoptosis. Mechanistically, increased generation of reactive oxygen species (ROS) and subsequently activated nuclear transcription factor-κB (NF-κB) signaling was found to contribute to the promotion of HCC cell growth and metastasis by COX7RP. Collectively, COX7RP plays a critical oncogenic role in hepatocellular carcinogenesis, supporting COX7RP as a novel prognostic factor and therapeutic target in HCC.

Genital Chlamydia infection in hyperlipidemic mouse models exacerbates atherosclerosis.

BACKGROUND AND AIMS: Atherosclerosis is a chronic inflammatory disease, and recent studies have shown that infection at remote sites can contribute to the progression of atherosclerosis in hyperlipidemic mouse models. In this report, we tested the hypothesis that genital Chlamydia infection could accelerate the onset and progression of atherosclerosis. METHODS: Apolipoprotein E (Apoe-/-) and LDL receptor knockout (Ldlr-/-) mice on a high-fat diet were infected intra-vaginally with Chlamydia muridarum. Atherosclerotic lesions on the aortic sinuses and in the descending aorta were assessed at 8-weeks post-infection. Systemic, macrophage, and vascular site inflammatory responses were assessed and quantified. RESULTS: Compared to the uninfected groups, infected Apoe-/- and Ldlr-/- mice developed significantly more atherosclerotic lesions in the aortic sinus and in the descending aorta. Increased lesions were associated with higher circulating levels of serum amyloid A-1, IL-1ß, TNF-α, and increased VCAM-1 expression in the aortic sinus, suggesting an association with inflammatory responses observed during C. muridarum infection. Genital infection courses were similar in Apoe-/-, Ldlr-/-, and wild type mice. Further, Apoe-/- mice developed severe uterine pathology with increased dilatations. Apoe-deficiency also augmented cytokine/chemokine response in C. muridarum infected macrophages, suggesting that the difference in macrophage response could have contributed to the genital pathology in Apoe-/- mice. CONCLUSIONS: Overall, these studies demonstrate that genital Chlamydia infection exacerbates atherosclerotic lesions in hyperlipidemic mouse and suggest a novel role for Apoe in full recovery of uterine anatomy after chlamydial infection.

Generation of Human Fatty Livers Using Custom-Engineered Induced Pluripotent Stem Cells with Modifiable SIRT1 Metabolism.

The mechanisms by which steatosis of the liver progresses to non-alcoholic steatohepatitis and end-stage liver disease remain elusive. Metabolic derangements in hepatocytes controlled by SIRT1 play a role in the development of fatty liver in inbred animals. The ability to perform similar studies using human tissue has been limited by the genetic variability in man. We generated human induced pluripotent stem cells (iPSCs) with controllable expression of SIRT1. By differentiating edited iPSCs into hepatocytes and knocking down SIRT1, we found increased fatty acid biosynthesis that exacerbates fat accumulation. To model human fatty livers, we repopulated decellularized rat livers with human mesenchymal cells, fibroblasts, macrophages, and human SIRT1 knockdown iPSC-derived hepatocytes and found that the human iPSC-derived liver tissue developed macrosteatosis, acquired proinflammatory phenotype, and shared a similar lipid and metabolic profiling to human fatty livers. Biofabrication of genetically edited human liver tissue may become an important tool for investigating human liver biology and disease.

Loss of Wnt Secretion by Macrophages Promotes Hepatobiliary Injury after Administration of 3,5-Diethoxycarbonyl-1, 4-Dihydrocollidine Diet.

Exposure of mice to a diet containing 3,5-diethoxycarbonyl-1, 4-dihydrocollidine (DDC) induces porphyrin accumulation, cholestasis, immune response, and hepatobiliary damage mimicking hepatic porphyria and sclerosing cholangitis. Although ß-catenin signaling promotes hepatocyte proliferation, and macrophages are a source of Wnts, the role of macrophage-derived Wnts in modulating hepatobiliary injury/repair remains unresolved. We investigated the effect of macrophage-specific deletion of Wntless, a cargo protein critical for cellular Wnt secretion, by feeding macrophage-Wntless-knockout (Mac-KO) and wild-type littermates a DDC diet for 14 days. DDC exposure induced Wnt11 up-regulation in macrophages. Mac-KO mice on DDC showed increased serum alkaline phosphatase, aspartate aminotransferase, direct bilirubin, and histologic evidence of more cell death, inflammation, and ductular reaction. There was impaired hepatocyte proliferation evidenced by Ki-67 immunostaining, which was associated with decreased hepatocyte ß-catenin activation and cyclin-D1 in Mac-KO. Mac-KO also showed increased CD45, F4/80, and neutrophil infiltration after DDC diet, along with increased expression of several proinflammatory cytokines and chemokines. Gene expression analyses of bone marrow-derived macrophages from Mac-KO mice and F4/80+ macrophages isolated from DDC-fed Mac-KO livers showed proinflammatory M1 polarization. In conclusion, this study shows that a lack of macrophage Wnt secretion leads to more DDC-induced hepatic injury due to impaired hepatocyte proliferation and increased M1 macrophages, which promotes immune-mediated cell injury.

Biofabrication of Autologous Human Hepatocytes for Transplantation: How Do We Get There?

Directed differentiation of hepatocytes from induced pluripotent stem cells (iPSCs) holds promise as source material for treating some liver disorders. The unlimited availability of perfectly differentiated iPSC-derived hepatocytes will dramatically facilitate cell therapies. While systems to manufacture large quantities of iPSC-derived cells have been developed, we have been unable to generate and maintain stable and mature adult liver cells ex vivo. This short review highlights important challenges and possible solutions to the current state of hepatocyte biofabrication for cellular therapies to treat liver diseases. Successful cell transplantation will require optimizing the best cell function, overcoming limitations to cell numbers and safety, as well as a number of other challenges. Collaboration among scientists, clinicians, and industry is critical for generating new autologous stem cell-based therapies to treat liver diseases.

Macrophages in the Aging Liver and Age-Related Liver Disease.

The number of individuals aged 65 or older is projected to increase globally from 524 million in 2010 to nearly 1. 5 billion in 2050. Aged individuals are particularly at risk for developing chronic illness, while being less able to regenerate healthy tissue and tolerate whole organ transplantation procedures. In the liver, these age-related diseases include non-alcoholic fatty liver disease, alcoholic liver disease, hepatitis, fibrosis, and cirrhosis. Hepatic macrophages, a population comprised of both Kupffer cells and infiltrating monocyte derived macrophages, are implicated in several chronic liver diseases and also play important roles in the homeostatic functions of the liver. The effects of aging on hepatic macrophage population dynamics, polarization, and function are not well understood. Studies performed on macrophages derived from other aged sources, such as the bone marrow, peritoneal cavity, lungs, and brain, demonstrate general reductions in autophagy and phagocytosis, dysfunction in cytokine signaling, and altered morphology and distribution, likely mediated by epigenetic changes and mitochondrial defects, that may be applicable to hepatic macrophages. This review highlights recent findings in macrophage developmental biology and function, particularly in the liver, and discusses the role of macrophages in various age-related liver diseases. A better understanding of the biology of aging that influences hepatic macrophages and thus the progression of chronic liver disease will be crucial in order to develop new interventions and treatments for liver disease in aging populations.

Mice lacking liver-specific ß-catenin develop steatohepatitis and fibrosis after iron overload.

BACKGROUND & AIMS: Iron overload disorders such as hereditary hemochromatosis and iron loading anemias are a common cause of morbidity from liver diseases and increase risk of hepatic fibrosis and hepatocellular carcinoma (HCC). Treatment options for iron-induced damage are limited, partly because there is lack of animal models of human disease. Therefore, we investigated the effect of iron overload in liver-specific ß-catenin knockout mice (KO), which are susceptible to injury, fibrosis and tumorigenesis following chemical carcinogen exposure. METHODS: Iron overload diet was administered to KO and littermate control (CON) mice for various times. To ameliorate an oxidant-mediated component of tissue injury, N-Acetyl-L-(+)-cysteine (NAC) was added to drinking water of mice on iron overload diet. RESULTS: KO on iron diet (KO +Fe) exhibited remarkable inflammation, followed by steatosis, oxidative stress, fibrosis, regenerating nodules and occurrence of occasional HCC. Increased injury in KO +Fe was associated with activated protein kinase B (AKT), ERK, and NF-κB, along with reappearance of ß-catenin and target gene Cyp2e1, which promoted lipid peroxidation and hepatic damage. Addition of NAC to drinking water protected KO +Fe from hepatic steatosis, injury and fibrosis, and prevented activation of AKT, ERK, NF-κB and reappearance of ß-catenin. CONCLUSIONS: The absence of hepatic ß-catenin predisposes mice to hepatic injury and fibrosis following iron overload, which was reminiscent of hemochromatosis and associated with enhanced steatohepatitis and fibrosis. Disease progression was notably alleviated by antioxidant therapy, which supports its chemopreventive role in the management of chronic iron overload disorders. LAY SUMMARY: Lack of animal models for iron overload disorders makes it hard to study the disease process for improving therapies. Feeding high iron diet to mice that lack the ß-catenin gene in liver cells led to increased inflammation followed by fat accumulation, cell death and wound healing that mimicked human disease. Administration of an antioxidant prevented hepatic injury in this model.