Deletion of NADPH oxidase 2 in chondrocytes exacerbates ethanol-mediated growth plate disruption in mice without major effects on bone architecture or gene expression

BACKGROUND

Excess reactive oxygen species generated by NADPH oxidase 2 (Nox2) in response to ethanol exposure mediate aspects of skeletal toxicity including increased osteoclast differentiation and activity. Because perturbation of chondrocyte differentiation in the growth plate by ethanol could be prevented by dietary antioxidants, we hypothesized that Nox2 in the growth plate was involved in ethanol-associated reductions in longitudinal bone growth.

METHODS

Nox2 conditional knockout mice were generated, where the essential catalytic subunit of Nox2, cytochrome B-245 beta chain (Cybb), is deleted in chondrocytes using a Cre-Lox model with Cre expressed from the collagen 2a1 promoter (Col2a1-Cre). Wild-type and Cre-Lox mice were fed an ethanol Lieber-DeCarli-based diet or pair-fed a control diet for 8 weeks.

RESULTS

Ethanol treatment significantly reduced the number of proliferating chondrocytes in the growth plate, enhanced bone marrow adiposity, shortened femurs, reduced body length, reduced cortical bone volume, and decreased mRNA levels of a number of osteoblast and chondrocyte genes. Conditional knockout of Nox2 enzymatic activity in chondrocytes did not consistently prevent any ethanol effects. Rather, knockout mice had fewer proliferating chondrocytes than wild-type mice in both the ethanol- and control-fed animals. Additional analysis of tibia samples from Nox4 knockout mice showed that loss of Nox4 activity also reduced the number of proliferating chondrocytes and altered chondrocyte size in the growth plate.

CONCLUSIONS

Although Nox enzymatic activity regulates growth plate development, ethanol-associated disruption of the growth plate morphology is independent of ethanol-mediated increases in Nox2 activity.

Nox4 expression in osteo-progenitors controls bone development in mice during early life

Tightly regulated and cell-specific NADPH-oxidases (Nox) represent one of the major sources of reactive oxygen species (ROS) signaling molecules that are involved in tissue development and stem cell self-renewal. We have characterized the role of Nox4 in osteo-progenitors during postnatal bone development. Nox4 expression in bone and ROS generation were increased during early osteoblast differentiation and bone development. Stromal osteoblastic cell self-renewal, proliferation and ROS production were significantly lower in samples from whole-body Nox4 knockout mice (Nox4^-/-) and conditional knockout (CKO) mice with depletion of Nox4 in the limb bud mesenchyme compared with those from control mice (Nox4^fl/fl), but they were reversed after 9 passages. In both sexes, bone volume, trabecular number and bone mineral density were significantly lower in 3-week old CKO and Nox4^-/- mice compared with Nox4^fl/fl controls. This was reflected in serum levels of bone formation markers alkaline phosphatase (ALP) and procollagen 1 intact N-terminal propeptide (P1NP). However, under-developed bone formation in 3-week old CKO and Nox4^-/- mice quickly caught up to levels of control mice by 6-week of age, remained no different at 13-week of age, and was reversed in 32-week old male mice. Osteoclastogenesis showed no differences among groups, however, CTX1 reflecting osteoclast activity was significantly higher in 3-week old male CKO and Nox4^-/- mice compared with control mice, and significantly lower in 32-week old Nox4^-/- mice compared with control mice. These data suggest that Nox4 expression and ROS signaling in bone and osteoblastic cells coordinately play an important role in osteoblast differentiation, proliferation and maturation.

Soy Formula Is Not Estrogenic and Does Not Result in Reproductive Toxicity in Male Piglets: Results from a Controlled Feeding Study

Soy infant formula which is fed to over half a million infants per year contains isoflavones such as genistein, which have been shown to be estrogenic at high concentrations. The developing testis is sensitive to estrogens, raising concern that the use of soy formulas may result in male reproductive toxicity. In the current study, male White-Dutch Landrace piglets received either sow milk (Sow), or were provided milk formula (Milk), soy formula (Soy), milk formula supplemented with 17-beta-estradiol (2 mg/kg/d) (M + E2) or supplemented with genistein (84 mg/L of diet; (M + G) from postnatal day 2 until day 21. E2 treatment reduced testis weight (p < 0.05) as percentage of body weight, significantly suppressed serum androgen concentrations, increased tubule area, Germ cell and Sertoli cell numbers (p < 0.05) relative to those of Sow or Milk groups. Soy formula had no such effects relative to Sow or Milk groups. mRNAseq revealed 103 differentially expressed genes in the M + E2 group compared to the Milk group related to endocrine/metabolic disorders. However, little overlap was observed between the other treatment groups. These data suggest soy formula is not estrogenic in the male neonatal piglet and that soy formula does not significantly alter male reproductive development.

Binge Ethanol Exposure in Mice Represses Expression of Genes Involved in Osteoblast Function and Induces Expression of Genes Involved in Osteoclast Differentiation Independently of Endogenous Catalase

Excessive ethanol consumption is a risk factor for osteopenia. Since a previous study showed that transgenic female mice with overexpression of catalase are partially protected from ethanol-mediated trabecular bone loss, we investigated the role of endogenous catalase in skeletal ethanol toxicity comparing catalase knockout to wild-type mice. We hypothesized that catalase depletion would exacerbate ethanol effects. The mice were tested in a newly designed binge ethanol model, in which 12-week-old mice were exposed to 4 consecutive days of gavage with ethanol at 3, 3, 4, and 4.5 g ethanol/kg body weight. Binge ethanol decreased the concentration of serum osteocalcin, a marker of bone formation. The catalase genotype did not affect the osteocalcin levels. RNA sequencing of femoral shaft RNA from males was conducted. Ethanol exposure led to significant downregulation of genes expressed in cells of the osteoblastic lineage with a role in osteoblastic function and collagen synthesis, including the genes encoding major structural bone proteins. Binge ethanol further induced a smaller set of genes with a role in osteoclastic differentiation. Catalase depletion affected genes with expression in erythroblasts and erythrocytes. There was no clear interaction between binge ethanol and the catalase genotype. In an independent experiment, we confirmed that the binge ethanol effects on gene expression were reproducible and occurred throughout the skeleton in males. In conclusion, the binge ethanol exposure, independently of endogenous catalase, reduces expression of genes involved in osteoblastic function and induces expression of genes involved in osteoclast differentiation throughout the skeleton in males.

Nox4 Expression Is Not Required for OVX-Induced Osteoblast Senescence and Bone Loss in Mice

Estrogen deficiency and aging play critical roles in the pathophysiology of bone as a result of increased oxidative stress. It has been suggested that prevention of NADPH oxidase- (Nox-) dependent accumulation of ROS may be an approach to potentially minimize bone loss caused by these conditions. Using ovariectomized (OVX) and Nox4 gene-deletion mouse models, we investigated the role of Nox4 in OVX-induced bone loss and osteoblast senescence signaling. Six-month-old WT C57Bl6 mice were allocated to a sham control group, OVX, and OVX plus E2 treatment group for 8 weeks. Decreased bone mass including BMD and BMC were found in the OVX group compared with the sham control (p < 0.05); E2 treatment completely reversed OVX-induced bone loss. Interestingly, the prevention of OVX-induced bone loss by E2 was associated with the elimination of increased senescence signaling in bone osteoblastic cells from the OVX group. E2 blunted OVX-induced p53 and p21 overexpression, but not p16 and Nox4 in bone. In addition, 8- and 11-month-old Nox4 KO female mice were OVX for 8 weeks. Significant bone loss and increased bone osteoblastic cell senescence signaling occurred not only in Nox4 KO OVX mice compared with sham-operated animals, but also in 11-month-old Nox4 KO sham mice compared with 8-month-old Nox4 KO sham mice (p < 0.05). These data suggest that Nox4-mediated ROS in bone osteoblastic cells may be dispensable for sex steroid deficiency-induced bone loss and senescence. © 2020 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

MicroRNA profiles were altered in neonatal piglet mammary glands following postnatal infant formula feeding

Postnatal dietary modulation of microRNAs (miRNAs) and effects on miRNA-mRNA interactions in tissues remain unknown. This study aimed to investigate whether dietary factors (formula vs. breastfeeding) affect mammary miRNA expression and to determine if these changes are concurrent with developmental alterations of the mammary gland in neonatal piglets. Female Yorkshire/Duroc piglets were fed sow's milk or cow's milk- or soy-based infant formula (from postnatal day 2 to day 21; n=6/group). Differentially expressed miRNAs were determined using mammary miRNA profiling, followed by miRNA and mRNA expressions characterized by quantitative reverse-transcription polymerase chain reaction. Milk and soy formulas reduced expressions of miR-1, -128, -133a, -193b, -206 and -27a; miRNA down-regulation altered mRNA expressions of genes (e.g., Ccnd1, Tgfb3, Igf1r and Tbx3) that were consistent with enhanced cell proliferation and suppressed apoptotic processes in the developing mammary gland. Interestingly, down-regulation of miR-1, -128 and -27a also correlated with increased mRNA genes such as Hmgcs and Hmgcr encoding cholesterol synthesis in the mammary glands in response to lower circulating cholesterol levels. Infant formula feeding affected mammary miRNA profiles in neonatal piglets, concurrent with increased expression of cell proliferation and cholesterol synthesis genes, suggesting early nutritional modulation of miRNAs may contribute to regulation of proliferative status and cholesterol homeostasis of developing mammary glands during infancy.

Skeletal Toxicity of Coplanar Polychlorinated Biphenyl Congener 126 in the Rat Is Aryl Hydrocarbon Receptor Dependent

Epidemiological evidence links polychlorinated biphenyls (PCBs) to skeletal toxicity, however mechanisms whereby PCBs affect bone are poorly studied. In this study, coplanar PCB 126 (5 μmol/kg) or corn oil vehicle was administered to N = 5 and 6 male and female, wild type (WT) or AhR -/- rats via intraperitoneal injection. Animals were sacrificed after 4 weeks. Bone length was measured; bone morphology was assessed by microcomputed tomography and dynamic histomorphometry. Reduced bone length was the only genotype-specific effect and only observed in males (p < .05). WT rats exposed to PCB 126 had reduced serum calcium, and smaller bones with reduced tibial length, cortical area, and medullary area relative to vehicle controls (p < .05). Reduced bone formation rate observed in dynamic histomorphometry was consistent with inhibition of endosteal and periosteal bone growth. The effects of PCB 126 were abolished in AhR -/- rats. Gene expression in bone marrow and shaft were assessed by RNA sequencing. Approximately 75% of the PCB-regulated genes appeared AhR dependent with 89 genes significantly (p < .05) regulated by both PCB 126 and knockout of the AhR gene. Novel targets significantly induced by PCB 126 included Indian hedgehog (Ihh) and connective tissue growth factor (Ctgf/Ccn2), which regulate chondrocyte proliferation and differentiation in the bone growth plate and cell-matrix interactions. These data suggest the toxic effects of PCB 126 on bone are mediated by AhR, which has direct effects on the growth plate and indirect actions related to endocrine disruption. These studies clarify important mechanisms underlying skeletal toxicity of dioxin-like PCBs and highlight potential therapeutic targets.

Reduced Serum Osteocalcin in High-Risk Alcohol Using People Living With HIV Does Not Correlate With Systemic Oxidative Stress or Inflammation: Data From the New Orleans Alcohol Use in HIV Study

BACKGROUND

HIV infection is now largely a chronic condition as a result of the success of antiretroviral therapy. However, several comorbidities have emerged in people living with HIV (PLWH), including alcohol use disorders and musculoskeletal disorders. Alcohol use has been associated with lower bone mineral density, alterations to circulating bone turnover markers, and hypocalcemia. The pathophysiological basis of bone loss in the PLWH population is unclear but has been suggested to be linked to oxidative stress and inflammation. To test the hypothesis that PLWH consuming excessive alcohol have altered markers of bone turnover and/or calcium homeostasis in association with oxidative stress, we correlated measurements of alcohol consumption with markers of oxidative stress and inflammation, serum calcium concentrations, and measurements of bone turnover, including c-terminal telopeptide cross-links (CTX-1) and osteocalcin.

METHODS

Data were drawn from cross-sectional baseline data from the ongoing New Orleans Alcohol Use in HIV (NOAH) study, comprised of 365 in care PLWH. Alcohol consumption measures (Alcohol Use Disorders Test, 30-day timeline follow-back calendar, and phosphatidylethanol [PEth]) were measured in a subcohort of 40 subjects selected based on highest and lowest PEth measurements. Multivariate linear regression was performed to test the relationships between alcohol consumption and systemic oxidative stress (4-hydroxynonenal; 4-HNE) and inflammation (c-reactive protein; CRP).

RESULTS

Serum calcium and CTX-1 did not differ significantly between the high and low-PEth groups. Individuals in the high-PEth group had significantly lower serum osteocalcin (median low-PEth group: 13.42 ng/ml, inter-quartile range [IQR] 9.26 to 14.99 ng/ml; median high-PEth group 7.39 ng/ml, IQR 5.02 to 11.25 ng/ml; p = 0.0005, Wilcoxon rank-sum test). Osteocalcin negatively correlated with PEth (Spearman r = -0.45, p = 0.05) and self-reported measures after adjusting for covariates. Alcohol consumption showed mild, but significant, positive associations with serum 4-HNE, but not with CRP. Osteocalcin did not correlate with either 4-HNE or CRP.

CONCLUSIONS

In this subcohort of PLWH, we detected significant associations between at-risk alcohol use and osteocalcin, and at-risk alcohol use and serum 4-HNE, suggesting suppression of bone formation independent of increased systemic oxidative stress with increasing alcohol consumption.

Infant Formula Feeding Increases Hepatic Cholesterol 7α Hydroxylase (CYP7A1) Expression and Fecal Bile Acid Loss in Neonatal Piglets

Background

During the postnatal feeding period, formula-fed infants have higher cholesterol synthesis rates and lower circulating cholesterol concentrations than their breastfed counterparts. Although this disparity has been attributed to the uniformly low dietary cholesterol content of typical infant formulas, little is known of the underlying mechanisms associated with this altered cholesterol metabolism phenotype.

Objective

We aimed to determine the molecular etiology of diet-associated changes in early-life cholesterol metabolism with the use of a postnatal piglet feeding model.

Methods

Two-day-old male and female White-Dutch Landrace piglets were fed either sow milk (Sow group) or dairy-based (Milk group; Similac Advance powder) or soy-based (Soy group; Emfamil Prosobee Lipil powder) infant formulas until day 21. In addition to measuring serum cholesterol concentrations, hepatic and intestinal genes involved in enterohepatic circulation of cholesterol and bile acids were analyzed by real-time reverse-transcriptase polymerase chain reaction and Western blot. Bile acid concentrations were measured by liquid chromatography-mass spectrometry in serum, liver, and feces.

Results

Compared with the Sow group, hepatic cholesterol 7α hydroxylase (CYP7A1) protein expression was 3-fold higher in the Milk group (P < 0.05) and expression was 10-fold higher in the Soy group compared with the Milk group (P < 0.05). Likewise, fecal bile acid concentrations were 3-fold higher in the Soy group compared with the Milk group (P < 0.05). Intestinal mRNA expression of fibroblast factor 19 (Fgf19) was reduced in the Milk and Soy groups, corresponding to 54% and 67% decreases compared with the Sow group. In the Soy group, small heterodimer protein (SHP) protein expression was 30% lower compared with the Sow group (P < 0.05).

Conclusions

These results indicate that formula feeding leads to increased CYP7A1 protein expression and fecal bile acid loss in neonatal piglets, and this outcome is linked to reduced efficacy in inhibiting CYP7A1 expression through FGF19 and SHP transcriptional repression mechanisms.

NOX4 Deletion in Male Mice Exacerbates the Effect of Ethanol on Trabecular Bone and Osteoblastogenesis

Chronic alcohol consumption increases bone resorption and decreases bone formation. A major component of ethanol (EtOH) pathology in bone is the generation of excess reactive oxygen species (ROS). The ROS-generating NADPH oxidase-4 (NOX4) is proposed to drive much of the EtOH-induced suppression of bone formation. Here, 13-week-old male wild-type (WT) and NOX4^-/- mice were pair fed (PF) a high-fat (35%), Lieber-DeCarli liquid diet with or without EtOH at 30% of their total calories for 12 weeks. Micro-computed tomography analysis demonstrated significant decreases in trabecular bone volume/total volume (BV/TV) percentage and cortical thickness in WT, EtOH-fed mice compared with PF controls. EtOH-fed NOX4^-/- mice also displayed decreased trabecular BV/TV and trabecular number compared with PF (P < 0.05). However, NOX4^-/- mice were protected against EtOH-induced decreases in cortical thickness (P < 0.05) and decreases in collagen1 and osteocalcin mRNA expression in cortical bone (P < 0.05). In WT and NOX4^-/- vertebral bone, EtOH suppressed expression of Wnt signaling components that promote osteoblast maturation. A role for NOX4 in EtOH inhibition of osteoblast differentiation was further demonstrated by protection against EtOH inhibition of osteoblastogenesis in ex vivo bone marrow cultures from NOX4^-/-, but not p47^phox-/- mice lacking active NADPH oxidase-2. However, bone marrow cultures from NOX4^-/- mice formed fewer osteoblastic colonies compared with WT cultures (P < 0.05), suggesting a role for NOX4 in the maintenance of mesenchymal progenitor cell populations. These data suggest that NOX4 deletion is partially protective against EtOH effects on osteoblast differentiation, but may predispose bone to osteogenic impairments.

Diet Supplementation with Soy Protein Isolate, but Not the Isoflavone Genistein, Protects Against Alcohol-Induced Tumor Progression in DEN-Treated Male Mice

Diethylnitrosamine-treated male mice were assigned to 4 groups: a casein-based 35% high fat ethanol liquid diet (EtOH), an EtOH diet made with soy protein isolate protein (EtOH/SOY), an EtOH liquid diet supplemented with genistein (EtOH/GEN) and a chow group. EtOH feeding, final concentration 5% (v/v), continued for 16 wks. EtOH increased incidence and multiplicity of basophilic lesions and adenomas compared to the chow group, (p < 0.05). The EtOH/SOY group had reduced adenoma progression when compared to the EtOH and EtOH/GEN group, (p < 0.05). Genistein supplementation had no protective effect. Soy feeding significantly reduced serum ALT concentrations (p < 0.05), decreased hepatic TNFα and CD-14 expression and decreased nuclear accumulation of NFκB protein in EtOH/SOY-treated mice compared to the EtOH group (p < 0.05). With respect to ceramides, high resolution MALDI-FTICR Imaging mass spectrometry revealed changes in the accumulation of long acyl chain ceramide species, in particular C18, in the EtOH group when compared to the EtOH/SOY group. Additionally, expression of acid ceramidase and sphingosine kinase 1 which degrade ceramide into sphingosine and convert sphingosine to sphingosine-1-phosphate (S1P) respectively and expression of S1P receptors S1PR2 and S1PR3 were all upregulated by EtOH and suppressed in the EtOH/SOY group, p < 0.05. EtOH feeding also increased hepatocyte proliferation and mRNA expression of β-catenin targets, including cyclin D1, MMP7 and glutamine synthase, which were reduced in the EtOH/SOY group, p < 0.05. These findings suggest that soy prevents tumorigenesis by reducing inflammation and by reducing hepatocyte proliferation through inhibition of EtOH-mediated β-catenin signaling. These mechanisms may involve blockade of sphingolipid signaling.

Adverse Effects of Nutraceuticals and Dietary Supplements

Over 70% of Americans take some form of dietary supplement every day, and the supplement industry is currently big business, with a gross of over $28 billion. However, unlike either foods or drugs, supplements do not need to be registered or approved by the US Food and Drug Administration (FDA) prior to production or sales. Under the Dietary Supplement Health and Education Act of 1994, the FDA is restricted to adverse report monitoring postmarketing. Despite widespread consumption, there is limited evidence of health benefits related to nutraceutical or supplement use in well-nourished adults. In contrast, a small number of these products have the potential to produce significant toxicity. In addition, patients often do not disclose supplement use to their physicians. Therefore, the risk of adverse drug-supplement interactions is significant. An overview of the major supplement and nutraceutical classes is presented here, together with known toxic effects and the potential for drug interactions.

Alcohol-associated intestinal dysbiosis impairs pulmonary host defense against Klebsiella pneumoniae

Chronic alcohol consumption perturbs the normal intestinal microbial communities (dysbiosis). To investigate the relationship between alcohol-mediated dysbiosis and pulmonary host defense we developed a fecal adoptive transfer model, which allows us to investigate the impact of alcohol-induced gut dysbiosis on host immune response to an infectious challenge at a distal organ, independent of prevailing alcohol use. Male C57BL/6 mice were treated with a cocktail of antibiotics (ampicillin, gentamicin, neomycin, vancomycin, and metronidazole) via daily gavage for two weeks. A separate group of animals was fed a chronic alcohol (or isocaloric dextrose pair-fed controls) liquid diet for 10 days. Microbiota-depleted mice were recolonized with intestinal microbiota from alcohol-fed or pair-fed (control) animals. Following recolonization groups of mice were sacrificed prior to and 48 hrs. post respiratory infection with Klebsiella pneumoniae. Klebsiella lung burden, lung immunology and inflammation, as well as intestinal immunology, inflammation, and barrier damage were examined. Results showed that alcohol-associated susceptibility to K. pneumoniae is, in part, mediated by gut dysbiosis, as alcohol-naïve animals recolonized with a microbiota isolated from alcohol-fed mice had an increased respiratory burden of K. pneumoniae compared to mice recolonized with a control microbiota. The increased susceptibility in alcohol-dysbiosis recolonized animals was associated with an increase in pulmonary inflammatory cytokines, and a decrease in the number of CD4+ and CD8+ T-cells in the lung following Klebsiella infection but an increase in T-cell counts in the intestinal tract following Klebsiella infection, suggesting intestinal T-cell sequestration as a factor in impaired lung host defense. Mice recolonized with an alcohol-dysbiotic microbiota also had increased intestinal damage as measured by increased levels of serum intestinal fatty acid binding protein. Collectively, these results suggest that alterations in the intestinal immune response as a consequence of alcohol-induced dysbiosis contribute to increased host susceptibility to Klebsiella pneumonia.

Partial Protection by Dietary Antioxidants Against Ethanol-Induced Osteopenia and Changes in Bone Morphology in Female Mice

BACKGROUND

Chronic alcohol consumption leads to increased fracture risk and an elevated risk of osteoporosis by decreasing bone accrual through increasing osteoclast activity and decreasing osteoblast activity. We have shown that this mechanism involves the generation of reactive oxygen species (ROS) produced by NADPH oxidases. It was hypothesized that different dietary antioxidants, N-acetyl cysteine (NAC; 1.2 mg/kg/d), and α-tocopherol (Vit.E; 60 mg/kg/d) would be able to attenuate the NADPH oxidase-mediated ROS effects on bone due to chronic alcohol intake.

METHODS

To study the effects of these antioxidants, female mice received a Lieber-DeCarli liquid diet containing ethanol (EtOH) with or without additional antioxidant for 8 weeks.

RESULTS

Tibias displayed decreased cortical bone mineral density in both the EtOH and EtOH + antioxidant groups compared to pair-fed (PF) and PF + antioxidant groups (p < 0.05). However, there was significant protection from trabecular bone loss in mice fed either antioxidant (p < 0.05). Microcomputed tomography analysis demonstrated a significant decrease in bone volume (bone volume/tissue volume) and trabecular number (p < 0.05), along with a significant increase in trabecular separation in the EtOH compared to PF (p < 0.05). In contrast, the EtOH + NAC and EtOH + Vit.E did not statistically differ from their respective PF controls. Ex vivo histologic sections of tibias were stained for nitrotyrosine, an indicator of intracellular damage by ROS, and tibias from mice fed EtOH exhibited significantly more staining than PF controls. EtOH treatment significantly increased the number of marrow adipocytes per mm as well as mRNA expression of aP2, an adipocyte marker in bone. Only NAC was able to reduce the number of marrow adipocytes to PF levels. EtOH-fed mice exhibited reduced bone length (p < 0.05) and had a reduced number of proliferating chondrocytes within the growth plate. NAC and Vit.E prevented this (p < 0.05).

CONCLUSIONS

These data show that alcohol's pathological effects on bone extend beyond decreasing bone mass and suggest a partial protective effect of the dietary antioxidants NAC and Vit.E at these doses with regard to alcohol effects on bone turnover and bone morphology.

Alcoholic Liver Disease in Rats Fed Ethanol as Part of Oral or Intragastric Low-Carbohydrate Liquid Diets

The intragastric administration of ethanol as part of a lowcarbohydrate diet results in alcohol hepatotoxicity. We aimed to investigate whether comparable liver injury can be achieved by oral diet intake. Male Sprague-Dawley rats were fed ethanol as part of low-carbohydrate diets for 36–42 days either intragastrically or orally. Liver pathology, blood ethanol concentration, serum alanine amino transferase (ALT), endotoxin level, hepatic CYP2E1 induction, and cytokine profiles were assessed. Both oral and intragastric low-carbohydrate ethanol diets resulted in marked steatosis with additional inflammation and necrosis accompanied by significantly increased serum ALT, high levels of CYP2E1 expression, and production of auto-antibodies against malondialdehyde and hydroxyethyl free radical protein adducts. However, cytokine profiles differed substantially between the groups, with significantly lower mRNA expression of the anti-inflammatory cytokine interleukin 4 observed in rats fed low-carbohydrate diets orally. Inflammation and necrosis were significantly greater in rats receiving low-carbohydrate alcohol diets intragastrically than orally. This was associated with a significant increase in liver tumor necrosis factor α and interleukin 1β gene expression in the intragastric model. Thus, oral low-carbohydrate diets produce more ethanol-induced liver pathology than oral high-carbohydrate diets, but hepatotoxicity is more severe when a low-carbohydrate diet plus ethanol is infused intragastrically and is accompanied by significant increases in levels of proinflammatory cytokines.

Effects of soy containing diet and isoflavones on cytochrome P450 enzyme expression and activity

Cytochromes P450 (CYPs) play an important role in metabolism and clearance of most clinically utilized drugs and other xenobiotics. They are important in metabolism of endogenous compounds including fatty acids, sterols, steroids and lipid-soluble vitamins. Dietary factors such as phytochemicals are capable of affecting CYP expression and activity, which may be important in diet-drug interactions and in the development of fatty liver disease, cardiovascular disease and cancer. One important diet-CYP interaction is with diets containing plant proteins, particularly soy protein. Soy diets are traditionally consumed in Asian countries and are linked to lower incidence of several cancers and of cardiovascular disease in Asian populations. Soy is also an important protein source in vegetarian and vegan diets and the sole protein source in soy infant formulas. Recent studies suggest that consumption of soy can inhibit induction of CY1 enzymes by polycyclic aromatic hydrocarbons (PAHs) which may contribute to cancer prevention. In addition, there are data to suggest that soy components promiscuously activate several nuclear receptors including PXR, PPAR and LXR resulting in increased expression of CYP3As, CYP4As and CYPs involved in metabolism of cholesterol to bile acids. Such soy-CYP interactions may alter drug pharmacokinetics and therapeutic efficacy and are associated with improved lipid homeostasis and reduced risk of cardiovascular disease. The current review summarizes results from in vitro; in vivo and clinical studies of soy-CYP interactions and examines the evidence linking the effects of soy diets on CYP expression to isoflavone phytoestrogens, particularly, genistein and daidzein that are associated with soy protein.

Reactive Oxygen Species Differentially Regulate Bone Turnover in an Age-Specific Manner in Catalase Transgenic Female Mice

Chronic ethyl alcohol (EtOH) consumption results in reactive oxygen species (ROS) generation in bone and osteopenia due to increased bone resorption and reduced bone formation. In this study, transgenic C57Bl/6J mice overexpressing human catalase (TgCAT) were used to test whether limiting excess hydrogen peroxide would protect against EtOH-mediated bone loss. Micro-computed tomography analysis of the skeletons of 6-week-old female chow-fed TgCAT mice revealed a high bone mass phenotype with increased cortical bone area and thickness as well as significantly increased trabecular bone volume (P < 0.05). Six-week-old wild-type (WT) and TgCAT female mice were chow fed or pair fed (PF) liquid diets with or without EtOH, approximately 30% of calories, for 8 weeks. Pair feeding of WT had no demonstrable effect on the skeleton; however, EtOH feeding of WT mice significantly reduced cortical and trabecular bone parameters along with bone strength compared with PF controls (P < 0.05). In contrast, EtOH feeding of TgCAT mice had no effect on trabecular bone compared with PF controls. At 14 weeks of age, there was significantly less trabecular bone and cortical cross-sectional area in TgCAT mice than WT mice (P < 0.05), suggesting impaired normal bone accrual with age. TgCAT mice expressed less collagen1α and higher sclerostin mRNA (P < 0.05), suggesting decreased bone formation in TgCAT mice. In conclusion, catalase overexpression resulted in greater bone mass than in WT mice at 6 weeks and lower bone mass at 14 weeks. EtOH feeding induced significant reductions in bone architecture and strength in WT mice, but TgCAT mice were partially protected. These data implicate ROS signaling in the regulation of bone turnover in an age-dependent manner, and indicate that excess hydrogen peroxide generation contributes to alcohol-induced osteopenia.

Formula diet alters small intestine morphology, microbial abundance and reduces VE-cadherin and IL-10 expression in neonatal porcine model

BACKGROUND

Breastfeeding is associated with a variety of positive health outcomes in children and is recommended exclusively for the first 6 months of life; however, 50-70 % of infants in the US are formula-fed. To test the hypothesis that immune system development and function in neonates and infants are significantly influenced by diet, 2-day old piglets were fed soy or milk formula (n = 6/group/gender) until day 21 and compared to a sow-fed group (n = 6/gender).

METHODS

Histomorphometric analyses of ileum, jejunum and Peyer's patches were carried out, to determine the inflammation status, mRNA and protein expression of pro-inflammatory, anti-inflammatory and growth-related chemokines and cytokines.

RESULTS

In formula-fed animals, increases in ileum and jejunum villus height and crypt depth were observed in comparison to sow-fed animals (jejunum, p < 0.01 villus height, p < 0.04 crypt depth; ileum p < 0.001 villus height, p < 0.002 crypt depth). In formula-fed the lymphoid follicle size (p < 0.01) and germinal centers (p < 0.01) with in the Peyer's patch were significantly decreased in comparison to sow-fed, indicating less immune education. In ileum, formula diet induced significant up-regulation of AMCFII, IL-8, IL-15, VEGFA, LIF, FASL, CXCL11, CCL4, CCL25 and down-regulation of IL-6, IL-9, IL-10, IL-27, IFNA4, CSF3, LOC100152038, and LOC100736831 at the transcript level. We have confirmed some of the mRNA data by measuring protein, and significant down-regulation of anti-inflammatory molecule IL-10 in comparison to sow-fed piglets was observed. To further determine the membrane protein expression in the ileum, VE-cadherin, occludin, and claudin-3, Western blot analyses were conducted. Sow fed piglets showed significantly more VE-Cadherin, which associated with levels of calcium, and putrescine measured. It is possible that differences in GI tract and immune development are related to shifts in the microbiome; notably, there were 5-fold higher amounts of Lactobacillaceae spp and 3 fold higher Clostridia spp in the sow fed group in comparison to milk formula-fed piglets, whereas in milk formula-fed pigs Enterobacteriaceae spp was 5-fold higher.

CONCLUSION

In conclusion, formula diet alters GI morphology, microbial abundance, intestinal barrier protein VE-cadherin and anti-inflammatory molecule IL-10 expression. Further characterization of formula effects could lead to modification of infant formula to improve immune function, reduce inflammation and prevent conditions such as allergies and infections.

N-acetylcysteine inhibits the up-regulation of mitochondrial biogenesis genes in livers from rats fed ethanol chronically

BACKGROUND

Chronic ethanol (EtOH) administration to experimental animals induces hepatic oxidative stress and up-regulates mitochondrial biogenesis. The mechanisms by which chronic EtOH up-regulates mitochondrial biogenesis have not been fully explored. In this work, we hypothesized that oxidative stress is a factor that triggers mitochondrial biogenesis after chronic EtOH feeding. If our hypothesis is correct, co-administration of antioxidants should prevent up-regulation of mitochondrial biogenesis genes.

METHODS

Rats were fed an EtOH-containing diet intragastrically by total enteral nutrition for 150 days, in the absence or presence of the antioxidant N-acetylcysteine (NAC) at 1.7 g/kg/d; control rats were administered isocaloric diets where carbohydrates substituted for EtOH calories.

RESULTS

EtOH administration significantly increased hepatic oxidative stress, evidenced as decreased liver total glutathione and reduced glutathione/glutathione disulfide ratio. These effects were inhibited by co-administration of EtOH and NAC. Chronic EtOH increased the expression of mitochondrial biogenesis genes including peroxisome proliferator-activated receptor gamma-coactivator-1 alpha and mitochondrial transcription factor A, and mitochondrial DNA; co-administration of EtOH and NAC prevented these effects. Chronic EtOH administration was associated with decreased mitochondrial mass, inactivation and depletion of mitochondrial complex I and complex IV, and increased hepatic mitochondrial oxidative damage, effects that were not prevented by NAC.

CONCLUSIONS

These results suggest that oxidative stress caused by chronic EtOH triggered the up-regulation of mitochondrial biogenesis genes in rat liver, because an antioxidant such as NAC prevented both effects. Because NAC did not prevent liver mitochondrial oxidative damage, extra-mitochondrial effects of reactive oxygen species may regulate mitochondrial biogenesis. In spite of the induction of hepatic mitochondrial biogenesis genes by chronic EtOH, mitochondrial mass and function decreased probably in association with mitochondrial oxidative damage. These results also predict that the effectiveness of NAC as an antioxidant therapy for chronic alcoholism will be limited by its limited antioxidant effects in mitochondria, and its inhibitory effect on mitochondrial biogenesis.

p47phox-Nox2-dependent ROS Signaling Inhibits Early Bone Development in Mice but Protects against Skeletal Aging

Bone remodeling is age-dependently regulated and changes dramatically during the course of development. Progressive accumulation of reactive oxygen species (ROS) has been suspected to be the leading cause of many inflammatory and degenerative diseases, as well as an important factor underlying many effects of aging. In contrast, how reduced ROS signaling regulates inflammation and remodeling in bone remains unknown. Here, we utilized a p47(phox) knock-out mouse model, in which an essential cytosolic co-activator of Nox2 is lost, to characterize bone metabolism at 6 weeks and 2 years of age. Compared with their age-matched wild type controls, loss of Nox2 function in p47(phox-/-) mice resulted in age-related switch of bone mass and strength. Differences in bone mass were associated with increased bone formation in 6-week-old p47(phox-/-) mice but decreased in 2-year-old p47(phox-/-) mice. Despite decreases in ROS generation in bone marrow cells and p47(phox)-Nox2 signaling in osteoblastic cells, 2-year-old p47(phox-/-) mice showed increased senescence-associated secretory phenotype in bone compared with their wild type controls. These in vivo findings were mechanistically recapitulated in ex vivo cell culture of primary fetal calvarial cells from p47(phox-/-) mice. These cells showed accelerated cell senescence pathway accompanied by increased inflammation. These data indicate that the observed age-related switch of bone mass in p47(phox)-deficient mice occurs through an increased inflammatory milieu in bone and that p47(phox)-Nox2-dependent physiological ROS signaling suppresses inflammation in aging.

Increased 4-hydroxynonenal protein adducts in male GSTA4-4/PPAR-α double knockout mice enhance injury during early stages of alcoholic liver disease

To test the significance of lipid peroxidation in the development of alcoholic liver injury, an ethanol (EtOH) liquid diet was fed to male 129/SvJ mice (wild-type, WT) and glutathione S-transferase A4-4-null (GSTA4-/-) mice for 40 days. GSTA4-/- mice were crossed with peroxisome proliferator-activated receptor-α-null mice (PPAR-α-/-), and the effects of EtOH in the resulting double knockout (dKO) mice were compared with the other strains. EtOH increased lipid peroxidation in all except WT mice (P < 0.05). Increased steatosis and mRNA expression of the inflammatory markers CXCL2, tumor necrosis factor-α (TNF-α), and α-smooth muscle actin (α-SMA) were observed in EtOH GSTA4-/- compared with EtOH WT mice (P < 0.05). EtOH PPAR-α-/- mice had increased steatosis, serum alanine aminotransferase (ALT), and hepatic CD3+ T cell populations and elevated mRNA encoding CD14, CXCL2, TNF-α, IL-6, CD138, transforming growth factor-β, platelet-derived growth factor receptor-β (PDGFR-β), matrix metalloproteinase (MMP)-9, MMP-13, α-SMA, and collagen type 1 compared with EtOH WT mice. EtOH-fed dKO mice displayed elevation of periportal hepatic 4-hydroxynonenal adducts and serum antibodies against malondialdehyde adducts compared with EtOH feeding of GSTA4-/-, PPAR-α-/-, and WT mice (P < 0.05). ALT was higher in EtOH dKO mice compared with all other groups (P < 0.001). EtOH-fed dKO mice displayed elevated mRNAs for TNF-α and CD14, histological evidence of fibrosis, and increased PDGFR, MMP-9, and MMP-13 mRNAs compared with the EtOH GSTA4-/- or EtOH PPAR-α-/- genotype (P < 0.05). These findings demonstrate the central role lipid peroxidation plays in mediating progression of alcohol-induced necroinflammatory liver injury, stellate cell activation, matrix remodeling, and fibrosis.

Soy protein isolate inhibits high-fat diet-induced senescence pathways in osteoblasts to maintain bone acquisition in male rats

Chronic consumption by experimental animals of a typical Western diet high in saturated fats and cholesterol during postnatal life has been demonstrated to impair skeletal development. However, the underlying mechanism by which high-fat, energy-dense diets affect bone-forming cell phenotypes is poorly understood. Here, we show that male weanling rats fed a diet containing 45% fat and 0.5% cholesterol made with casein (HF-Cas) for 6 weeks displayed lower bone mineral density and strength compared with those of AIN-93G-fed dietary controls. Substitution of casein with soy protein isolate (SPI) in the high-fat diet (HF-SPI) prevented these effects. The bone-sparing effects of SPI were associated with prevention of HF-Cas-induced osteoblast senescence pathways through suppression of the p53/p21 signaling pathways. HF-Cas-fed rats had increased caveolin-1 and down-regulated Sirt1, leading to activations of peroxisome proliferator-activated receptor γ (PPARγ) and p53/p21, whereas rats fed HF-SPI suppressed caveolin-1 and activated Sirt1 to deacetylate PPARγ and p53 in bone. Treatment of osteoblastic cells with nonesterified free fatty acid (NEFA) increased cell senescence signaling pathways. Isoflavones significantly blocked activations of senescence-associated β-galactosidase and PPARγ/p53/p21 by NEFA. Finally, replicative senescent osteoblastic cells and bone marrow mesenchymal ST2 cells exhibited behavior similar to that of cells treated with NEFA and in vivo bone cells in rats fed the HF-Cas diet. These results suggest that (1) high concentrations of NEFA occurring with HF intake are mediators of osteoblast cell senescence leading to impairment of bone development and acquisition and (2) the molecular mechanisms underlying the SPI-protective effects involve isoflavone-induced inhibition of osteoblastic cell senescence to prevent HF-induced bone impairments.

Alcohol consumption, Wnt/β-catenin signaling, and hepatocarcinogenesis

Alcohol is a well-established risk factor for hepatocellular carcinoma, and the mechanisms by which alcohol liver cancer is complex. It has been suggested that ethanol (EtOH) metabolism may enhance tumor progression by increasing hepatocyte proliferation. To test this hypothesis, ethanol (EtOH) feeding of male mice began 7 weeks post-injection of the chemical carcinogen diethylnitrosamine (DEN), and continued for 16 weeks, with a final EtOH concentration of 28% of total calories. As expected, EtOH increased the total number of cancerous foci and liver tumors identified in situ fixed livers from the EtOH+DEN group compared to corresponding pair-fed (PF)+DEN and chow+DEN control groups. In the EtOH+DEN group, tumor multiplicity corresponded to a 3- to 4-fold increase in proliferation and immunohistochemical staining of β-catenin in non-tumorigenic hepatocytes when compared to the PF+DEN and chow+DEN groups, p<0.05. Analysis of EtOH-treated livers from a previously published rat model of chronic liver disease revealed increases in hepatocyte proliferation accompanied by a hepatic depletion of retinol and retinoic acid stores (p<0.05), nuclear accumulation of β-catenin (p<0.05), increased cytosolic expression p-GSK3β (p<0.05), significant upregulation of soluble Wnts, Wnt2, and Wnt7a, and increased expression of several β-catenin targets involved in tumor promotion and progression, cyclin D1, c-myc, WISP1, and MMP7 (p<0.05). These data suggest that chronic EtOH consumption activates the Wnt/β-catenin signaling pathway, which increases hepatocyte proliferation thus promoting tumorigenesis following an initiating insult in the liver.

Trace element status and zinc homeostasis differ in breast and formula-fed piglets

Differences in trace element composition and bioavailability between breast milk and infant formulas may affect metal homeostasis in neonates. However, there is a paucity of controlled studies in this area. Here, piglets were fed soy infant formula (soy), cow's milk formula (milk), or were allowed to suckle from the sow from PND2 to PND21. Serum iron concentrations were higher in formula-fed compared to breastfed piglets (P < 0.05). Serum zinc values were higher in milk compared to breastfed or soy groups (P < 0.05). Zinc transporter Zip4 mRNA was elevated in small intestine of the soy compared to breastfed group (P < 0.05). Transporter Znt1 mRNA was greater in small intestine of both formula-fed groups and in liver of the milk compared to the breastfed group (P < 0.05). Metallothionein Mt1 mRNA expression was higher in small intestine and liver of milk compared to breastfed and soy groups (P < 0.05). In liver, metallothionein protein levels and protein bound zinc were also highly elevated in the milk compared to other groups (P < 0.05). mRNA encoding the hepatic zinc-regulated gene Gclc was higher in the milk than soy group (P < 0.05). ChIP assay revealed increased binding of the zinc-regulated transcription factor MTF1 to the promoters of hepatic Mt3 and Gclc genes in the milk compared to the soy group. These data provide evidence that trace element status differs in breastfed, milk-fed, and soy-fed piglets and that despite similar levels of dietary supplementation, allows strong causal inference that significant differences in serum zinc after cow's milk formula compared to soy formula consumption result in compensatory changes in expression of zinc transporters, binding proteins, and zinc-regulated genes.

Genistein supplementation increases bone turnover but does not prevent alcohol-induced bone loss in male mice

Chronic alcohol consumption results in bone loss through increased bone resorption and decreased bone formation. These effects can be reversed by estradiol (E2) supplementation. Soy diets are suggested to have protective effects on bone loss in men and women, as a result of the presence of soy protein-associated phytoestrogens such as genistein (GEN). In this study, male mice were pair-fed (PF), a control diet, an ethanol (EtOH) diet, or EtOH diet supplemented with 250 mg/kg of GEN for 8 weeks to test if GEN protects against bone loss associated with chronic drinking. Interestingly, alcohol consumption reduced cortical area and thickness and trabecular bone volume in both EtOH and EtOH/GEN groups when compared to the corresponding PF and PF/GEN controls, P < 0.05. However, in the trabecular bone compartment, we observed a significant increase in overall trabecular bone density in the PF/GEN group compared to the PF controls. Bone loss in the EtOH-treated mice was associated with the inhibition of osteoblastogenesis as indicated by decreased alkaline phosphatase staining in ex vivo bone marrow cultures, P < 0.05. GEN supplementation improved osteoblastogenesis in the EtOH/GEN cultures compared to the EtOH group, P < 0.05. Vertebral expression of bone-formation markers, osteocalcin, and runt-related transcription factor 2 (Runx2) was also significantly up-regulated in the PF/GEN and EtOH/GEN groups compared to the PF and EtOH-treated groups. GEN supplementation also increased the expression of receptor activator of nuclear factor κ-B ligand (RANKL) in the PF/GEN, an increase that persisted in the EtOH/GEN-treated animals (P < 0.05), and increased basal hydrogen peroxide production and RANKL mRNA expression in primary bone marrow cultures in vitro, P < 0.05. These findings suggest that GEN supplementation increases the overall bone remodeling and, in the context of chronic alcohol consumption, does not protect against the oxidative stress-associated EtOH-mediated bone resorption.

Short term feeding of a high fat diet exerts an additive effect on hepatocellular damage and steatosis in liver-specific PTEN knockout mice

BACKGROUND

Hepatospecific deletion of PTEN results in constitutive activation of Akt and increased lipogenesis. In mice, the addition of a high fat diet (HFD) downregulates lipogenesis. The aim of this study was to determine the effects of a HFD on hepatocellular damage induced by deletion of PTEN.

METHODS

12 Week old male flox/flox hepatospecific PTEN mice (PTENf/f) or Alb-Cre controls were fed a HFD composed of 45% fat-derived calories (from corn oil) or a normal chow. Animals were then analyzed for hepatocellular damage, oxidative stress and expression of enzymes involved in fatty acid metabolism.

RESULTS

In the Alb-Cre animals, the addition of a HFD resulted in a significant increase in liver triglycerides and altered REDOX capacity as evidenced by increased GPX activity, decreased GST activity and decreased hepatic concentrations of GSSG. In addition, SCD2, ACLY and FASN were all downregulated by the addition of HFD. Furthermore, expression of PPARα and PPARα-dependent proteins Cyp4a and ACSL1 were upregulated. In the PTENf/f mice, HFD resulted in significant increased in ALT, serum triglycerides and decreased REDOX capacity. Although expression of fatty acid synthetic enzymes was elevated in the chow fed PTENf/f group, the addition of HFD resulted in SCD2, ACLY and FASN downregulation. Compared to the Alb-Cre HFD group, expression of PGC1α, PPARα and its downstream targets ACSL and Cyp4a were upregulated in PTENf/f mice.

CONCLUSIONS

These data suggest that during conditions of constitutive Akt activation and increased steatosis, the addition of a HFD enhances hepatocellular damage due to increased CD36 expression and altered REDOX status. In addition, this work indicates HFD-induced hepatocellular damage occurs in part, independently of Akt signaling.

Alcohol consumption promotes diethylnitrosamine-induced hepatocarcinogenesis in male mice through activation of the Wnt/β-catenin signaling pathway

Although alcohol effects within the liver have been extensively studied, the complex mechanisms by which alcohol causes liver cancer are not well understood. It has been suggested that ethanol (EtOH) metabolism promotes tumor growth by increasing hepatocyte proliferation. In this study, we developed a mouse model of tumor promotion by chronic EtOH consumption in which EtOH feeding began 46 days after injection of the chemical carcinogen diethylnitrosamine (DEN) and continued for 16 weeks. With a final EtOH concentration of 28% of total calories, we observed a significant increase in the total number of preneoplastic foci and liver tumors per mouse in the EtOH+DEN group compared with corresponding pair-fed (PF)+DEN and chow+DEN control groups. We also observed a 4-fold increase in hepatocyte proliferation (P < 0.05) and increased cytoplasmic staining of active-β-catenin in nontumor liver sections from EtOH+DEN mice compared with PF+DEN controls. In a rat model of alcohol-induced liver disease, we found increased hepatocyte proliferation (P < 0.05); depletion of retinol and retinoic acid stores (P < 0.05); increased expression of cytosolic and nuclear expression of β-catenin (P < 0.05) and phosphorylated-glycogen synthase kinase 3β (p-GSK3β), P < 0.05; significant upregulation in Wnt7a mRNA expression; and increased expression of several β-catenin targets, including, glutamine synthetase (GS), cyclin D1, Wnt1 inducible signaling pathways protein (WISP1), and matrix metalloproteinase-7(MMP7), P < 0.05. These data suggest that chronic EtOH consumption activates the Wnt/β-catenin signaling pathways to increase hepatocyte proliferation, thus promoting tumorigenesis following an initiating insult to the liver.

Diet-derived phenolic acids regulate osteoblast and adipocyte lineage commitment and differentiation in young mice

A blueberry (BB)-supplemented diet has been previously shown to significantly stimulate bone formation in rapidly growing male and female rodents. Phenolic acids (PAs) are metabolites derived from polyphenols found in fruits and vegetables as a result of the actions of gut bacteria, and they were found in the serum of rats fed BB-containing diet. We conducted in vitro studies with PAs and demonstrated stimulation of osteoblast differentiation and proliferation. On the other hand, adipogenesis was inhibited. To more fully understand the mechanistic actions of PAs on bone formation, we administered hippuric acid, one of the major metabolites found in animal circulation after BB consumption, to prepubertal female mice for 2 weeks. We found that hippuric acid was able to stimulate bone-forming gene expression but suppress PPARγ expression, leading to increased bone mass dose-dependently. Cellular signaling studies further suggested that the skeletal effects of PAs appeared to be mediated through activation of G-protein-coupled receptor 109A and downstream p38 MAP kinase and osterix. In conclusion, PAs are capable of altering the mesenchymal stem cell differentiation program and merit investigation as potential dietary therapeutic alternatives to drugs for degenerative bone disorders. © 2014 American Society for Bone and Mineral Research.

Loss of functional NADPH oxidase 2 protects against alcohol-induced bone resorption in female p47phox-/- mice

BACKGROUND

In bone, NADPH oxidase (NOX)-derived reactive oxygen species (ROS) superoxide and/or hydrogen peroxide are an important stimulus for osteoclast differentiation and activity. Previously, we have demonstrated that chronic ethanol (EtOH) consumption generates excess NOX-dependent ROS in osteoblasts, which functions to stimulate nuclear factor kappa-β receptor ligand (RANKL)-RANK signaling, thus increasing osteoclastogenesis and activity. This activity can be blocked by co-administration of EtOH with the pan-NOX inhibitor diphenylene idonium (DPI).

METHODS

To test whether EtOH-induced bone loss is dependent on a functional NOX2 enzyme, 6-week-old female C57BL/6J-Ncf1/p47phox(-/-) (p47phox KO) and wild-type (WT) mice were pair-fed EtOH diets for 40 days. Bone loss was assessed by 3-point bending, micro-computed tomography and static histomorphometric analysis. Additionally, ST2 cultured cells were co-treated with EtOH and NOX inhibitors, DPI, gliotoxin, and plumbagin, after which changes in ROS production, and in RANKL and NOX mRNA expression were analyzed.

RESULTS

In WT mice, EtOH treatment significantly reduced bone density and mechanical strength, and increased total osteoclast number and activity. In EtOH-treated p47phox KO mice, bone density and mechanical strength were completely preserved. EtOH p47phox KO mice had no changes in osteoclast numbers or activity, and no elevations in serum CTX or RANKL gene expression (p < 0.05). In both WT and p47phox KO mice, EtOH feeding reduced biochemical markers of bone formation (p < 0.05). In vitro EtOH exposure of ST2 cells increased ROS, which was blocked by pretreating with DPI or the NOX2 inhibitor gliotoxin. EtOH-induced RANKL and NOX2 gene expression were inhibited by the NOX4-specific inhibitor plumbagin.

CONCLUSIONS

These data suggest that NOX2-derived ROS is necessary for EtOH-induced bone resorption. In osteoblasts, NOX2 and NOX4 appear to work in tandem to increase RANKL expression, whereas EtOH-mediated inhibition of bone formation occurs via a NOX2-independent mechanism.

Feeding soy protein isolate and treatment with estradiol have different effects on mammary gland morphology and gene expression in weanling male and female rats

Isoflavones are phytochemical components of soy diets that bind weakly to estrogen receptors (ERs). To study potential estrogen-like actions of soy in the mammary gland during early development, we fed weanling male and female Sprague-Dawley rats a semipurified diet with casein as the sole protein source from postnatal day 21 to 33, the same diet substituting soy protein isolate (SPI) for casein, or the casein diet supplemented with estradiol (E2) at 10 μg/kg/day. In contrast to E2, the SPI diet induced no significant change in mammary morphology. In males, there were 34 genes for which expression was changed ≥2-fold in the SPI group vs. 509 changed significantly by E2, and 8 vs. 174 genes in females. Nearly half of SPI-responsive genes in males were also E2 responsive, including adipogenic genes. Serum insulin was found to be decreased by the SPI diet in males. SPI and E2 both downregulated the expression of ERα ( Esr1) in males and females, and ERβ ( Esr2) only in males. Chromatin immunoprecipitation revealed an increased binding of ERα to the promoter of the progesterone receptor ( Pgr) and Esr1 in both SPI- and E2-treated males compared with the casein group but differential recruitment of ERβ. ER promoter binding did not correlate with differences in Pgr mRNA expression. This suggests that SPI fails to recruit appropriate co-activators at E2-inducible genes. Our results indicate that SPI behaves like a selective estrogen receptor modulator rather than a weak estrogen in the developing mammary gland.

Maternal obesity enhances white adipose tissue differentiation and alters genome-scale DNA methylation in male rat offspring

The risk of obesity (OB) in adulthood is strongly influenced by maternal body composition. Here we examined the hypothesis that maternal OB influences white adipose tissue (WAT) transcriptome and increases propensity for adipogenesis in the offspring, prior to the development of OB, using an established model of long-term metabolic programming. Employing an overfeeding-based rat model, in which exposure to OB is limited to preconception and gestation alone, we conducted global transcriptomic profiling in WAT, and gene/protein expression analysis of lipogenic and adipogenic pathways and examined adipogenic differentiation of WAT stromal-vascular cells ex vivo. Using reduced representation bisulfite sequencing we also evaluated genome-scale changes in DNA methylation in offspring WAT. Maternal OB led to extensive changes in expression of genes (± 1.8-fold, P ≤ .05), revealing a distinct up-regulation of lipogenic pathways in WAT. mRNA expression of a battery of sterol regulatory element-binding protein-1-regulated genes was increased in OB-dam offspring, which were confirmed by immunoblotting. In conjunction with lipogenic gene expression, OB-dam offspring showed increased glucose transporter-4 mRNA/protein expression and greater AKT phosphorylation following acute insulin challenge, suggesting sensitization of insulin signaling in WAT. Offspring of OB dams also exhibited increased in vivo expression of adipogenic regulators (peroxisome proliferator-activated receptor-γ, CCAAT enhancer binding protein α [C/EBP-α] and C/EBP-β), associated with greater ex vivo differentiation of WAT stromal-vascular cells. These transcriptomic changes were associated with alterations in DNA methylation of CpG sites and CGI shores, proximal to developmentally important genes, including key pro-adipogenic factors (Zfp423 and C/EBP-β). Our findings strongly suggest that the maternal OB in utero alters adipocyte commitment and differentiation via epigenetic mechanisms.

Soy protein isolates prevent loss of bone quantity associated with obesity in rats through regulation of insulin signaling in osteoblasts

In both rodents and humans, excessive consumption of a typical Western diet high in saturated fats and cholesterol is known to result in disruption of energy metabolism and development of obesity and insulin resistance. However, how these high-fat, energy-dense diets affect bone development, morphology, and modeling is poorly understood. Here we show that male weanling rats fed a high-fat (HF) diet containing 45% fat and 0.5% cholesterol made with casein (HF-Cas) for 6 wk displayed a significant increase in bone marrow adiposity and insulin resistance. Substitution of casein with soy protein isolate (SPI) in the HF diet (HF-SPI) prevented these effects. Maintenance of bone quantity in the SPI-fed rats was associated with increased undercarboxylated osteocalcin secretion and altered JNK/IRS1/Akt insulin signaling in osteoblasts. The HF-Cas group had significantly greater serum nonesterified free fatty acid (NEFA) concentrations than controls, whereas the HF-SPI prevented this increase. In vitro treatment of osteoblasts or mesenchymal stromal ST2 cells with NEFAs significantly decreased insulin signaling. An isoflavone mixture similar to that found in serum of HF-SPI rats significantly increased in vitro osteoblast proliferation and blocked significantly reduced NEFA-induced insulin resistance. Finally, insulin/IGF1 was able to increase both osteoblast activity and differentiation in a set of in vitro studies. These results suggest that high-fat feeding may disrupt bone development and modeling; high concentrations of NEFAs and insulin resistance occurring with high fat intake are mediators of reduced osteoblast activity and differentiation; diets high in soy protein may help prevent high dietary fat-induced bone impairments; and the molecular mechanisms underlying the SPI-protective effects involve isoflavone-induced normalization of insulin signaling in bone.

Medium chain triglycerides dose-dependently prevent liver pathology in a rat model of non-alcoholic fatty liver disease

Metabolic syndrome is often accompanied by development of hepatic steatosis and less frequently by non-alcoholic fatty liver disease (NAFLD) leading to non-alcoholic steatohepatitis (NASH). Replacement of corn oil with medium chain triacylglycerols (MCT) in the diets of alcohol-fed rats has been shown to protect against steatosis and alcoholic liver injury. The current study was designed to determine if a similar beneficial effect of MCT occurs in a rat model of NAFLD. Groups of male rats were isocalorically overfed diets containing 10%, 35% or 70% total energy as corn oil or a 70% fat diet in which corn oil was replaced with increasing concentrations of saturated fat (18:82, beef tallow:MCT oil) from 20% to 65% for 21 days using total enteral nutrition (TEN). As dietary content of corn oil increased, hepatic steatosis and serum alanine amino transferases were elevated (P < 0.05). This was accompanied by greater expression of cytochrome P450 enzyme CYP2E1 (P < 0.05) and higher concentrations of polyunsaturated 18:2 and 20:4 fatty acids (FA) in the hepatic lipid fractions (P < 0.05). Keeping the total dietary fat at 70%, but increasing the proportion of MCT-enriched saturated fat resulted in a dose-dependent reduction in steatosis and necrosis without affecting CYP2E1 induction. There was no incorporation of C8-C10 FAs into liver lipids, but increasing the ratio of MCT to corn oil: reduced liver lipid 18:2 and 20:4 concentrations; reduced membrane susceptibility to radical attack; stimulated FA β- and ω-oxidation as a result of activation of peroxisomal proliferator activated receptor (PPAR)α, and appeared to increase mitochondrial respiration through complex III. These data suggest that replacing unsaturated fats like corn oil with MCT oil in the diet could be utilized as a potential treatment for NAFLD.

Blueberry consumption prevents loss of collagen in bone matrix and inhibits senescence pathways in osteoblastic cells

Ovariectomy (OVX)-induced bone loss has been linked to increased bone turnover and higher bone matrix collagen degradation as the result of osteoclast activation. However, the role of degraded collagen matrix in the fate of resident bone-forming cells is unclear. In this report, we show that OVX-induced bone loss is associated with profound decreases in collagen 1 and Sirt1. This was accompanied by increases in expression and activity of the senescence marker collagenase and expression of p16/p21 in bone. Feeding a diet supplemented with blueberries (BB) to pre-pubertal rats throughout development or only prior to puberty [postnatal day 21 (PND21) to PND34] prevents OVX-induced effects on expression of these molecules at PND68. In order to provide more evidence and gain a better understanding on the association between bone collagen matrix and resident bone cell fate, in vitro studies on the cellular senescence pathway using primary calvarial cells and three cell lines (ST2 cells, OB6, and MLO-Y4) were conducted. We found that senescence was inhibited by collagen in a dose-response manner. Treatment of cells with serum from OVX rats accelerated osteoblastic cell senescence pathways, but serum from BB-fed OVX rats had no effect. In the presence of low collagen or treatment with OVX rat serum, ST2 cells exhibited higher potential to differentiate into adipocytes. Finally, we demonstrated that bone cell senescence is associated with decreased Sirt1 expression and activated p53, p16, and p21. These results suggest that (1) a significant prevention of OVX-induced bone cell senescence from adult rats can occur after only 14 days consumption of a BB-containing diet immediately prior to puberty, and (2) the molecular mechanisms underlying this effect involves, at least in part, prevention of collagen degradation.

Female mice lacking p47phox have altered adipose tissue gene expression and are protected against high fat-induced obesity

The current study was designed to determine if the NADPH-oxidase NOX2 plays a role in development of obesity after high fat feeding. Wild-type (WT) mice and mice lacking the essential cytosolic NOX2 system component p47phox (P47KO mice) were fed AIN-93G diets or high-fat diets (HFD) containing 45% fat and 0.5% cholesterol for 13 wk from weaning. Fat mass was increased to a similar degree by HFD in males of both genotypes ( P < 0.05). However, female P47KO-HFD mice had no increase in adiposity or adipocyte size relative to female WT-HFD mice. Resistance to HFD-driven obesity in P47KO females was associated with increased expression of hepatic TFAM and UCP-2 mRNA, markers of mitochondrial number and uncoupling, and increased expression of hepatic mitochondrial respiratory complexes and whole body energy expenditure in response to HFD. Microarray analysis revealed significantly lower expression of mRNA encoding genes linked to energy metabolism, adipocyte differentiation (PPARγ), and fatty acid uptake (CD36, lipoprotein lipase), in fat pads from female P47KO-HFD mice compared with WT-HFD females. Moreover, differentiation of preadipocytes ex vivo was suppressed more by 17β-estradiol in cells from P47KO compared with cells from WT females in conjunction with overexpression of mRNA for Pref-1 ( P < 0.05). HFD mice of both sexes were resistant to the development of hyperglycemia and hepatic steatosis ( P < 0.05) and had reduced serum triglycerides, leptin, and adiponectin relative to WT-HFD mice ( P < 0.05). These data suggest that NOX2 is an important regulator of metabolic homeostasis and diet-induced obesity.

Mammary gland morphology and gene expression differ in female rats treated with 17β-estradiol or fed soy protein isolate

Soy foods have been suggested to have both positive health benefits and potentially adverse effects as a result of their content of phytoestrogens. However, studies on the estrogenicity of soy foods are lacking. Here we directly compared the effects of soy protein isolate (SPI), the protein in soy infant formula, with those of 17β-estradiol (E2), on global gene expression profiles and morphology in the female rat mammary gland. Rats were fed AIN-93G diets containing casein or SPI beginning on postnatal d 30. Rats were ovariectomized on postnatal d 50 and treated with 5 μg/kg/d E2 or vehicle for 14 d. Microarray analysis revealed that E2 treatment altered expression of 780 genes more than or equal to 2-fold (P < 0.05), whereas SPI feeding altered expression of only 53 genes more than or equal to 2-fold. Moreover, the groups had only 10 genes in common to increase more than or equal to 2-fold. The combination of SPI feeding and E2 altered expression of 422 genes and reversed E2 effects on many mRNAs, including those involved in the c-myc signaling pathway, cyclin D1, and Ki67. ERα binding to its response element on the Tie-2/Tek and progesterone receptor promoters was increased by E2, but not SPI, and this promoter binding was suppressed by the combination of E2 + SPI for the Tie-2/Tek promoter but increased for the progesterone receptor promoter (P < 0.05). SPI reduced the ratio of epithelial to fat pad area and E2 + SPI reduced both epithelial and fat pad area (P < 0.05). These data suggest that SPI is only minimally estrogenic in the rat mammary gland even in the absence of endogenous estrogens.

Vitamin D supplementation protects against bone loss associated with chronic alcohol administration in female mice

Chronic alcohol abuse results in decreased bone mineral density (BMD), which can lead to increased fracture risk. In contrast, low levels of alcohol have been associated with increased BMD in epidemiological studies. Alcohol's toxic skeletal effects have been suggested to involve impaired vitamin D/calcium homeostasis. Therefore, dietary vitamin D supplementation may be beneficial in reducing bone loss associated with chronic alcohol consumption. Six-week-old female C57BL/6J mice were pair-fed ethanol (EtOH)-containing liquid diets (10 or 36% total calories) for 78 days. EtOH exposure at 10% calories had no effects on any measured bone or serum parameter. EtOH consumption at 36% of calories reduced BMD and bone strength (P<0.05), decreased osteoblastogenesis, increased osteoclastogenesis, suppressed 1,25-hydroxyvitamin D3 [1,25(OH)2D3] serum concentrations (P<0.05), and increased apoptosis in bone cells compared with pair-fed controls. In a second study, female mice were pair-fed 30% EtOH diets with or without dietary supplementation with vitamin D3 (cholecalciferol; VitD) for 40 days. VitD supplementation in the EtOH diet protected against cortical bone loss, normalized alcohol-induced hypocalcaemia, and suppressed EtOH-induced expression of receptor of nuclear factor-κB ligand mRNA in bone. In vitro, pretreatment of 1,25(OH)2D3 in osteoblastic cells inhibited EtOH-induced apoptosis. In EtOH/VitD mice circulating 1,25(OH)2D3 was lower compared with mice receiving EtOH alone (P<0.05), suggesting increased sensitivity to feedback control of VitD metabolism in the kidney. These findings suggest dietary VitD supplementation may prevent skeletal toxicity in chronic drinkers by normalizing calcium homeostasis, preventing apoptosis, and suppressing EtOH-induced increases in bone resorption.

Dietary fat source alters hepatic gene expression profile and determines the type of liver pathology in rats overfed via total enteral nutrition

To determine if dietary fat composition affects the progression of nonalcoholic fatty liver disease (NAFLD), we overfed male Sprague-Dawley rats low (5%) or high (70%) fat diets with different fat sources: olive oil (OO), corn oil (CO), or echium oil (EO), with total enteral nutrition (TEN) for 21 days. Overfeeding of the 5% CO or 5% EO diets resulted in less steatosis than 5% OO (P < 0.05). Affymetrix array analysis revealed significant differences in hepatic gene expression signatures associated with greater fatty acid synthesis, ChREBP, and SREBP-1c signaling and increased fatty acid transport (P < 0.05) in the 5% OO compared with 5% CO group. The OO groups had macrosteatosis, but no evidence of oxidative stress or necrosis. The 70% CO and 70% EO groups had a mixture of micro- and macrosteatosis or only microsteatosis, respectively; increased oxidative stress; and increased necrotic injury relative to their respective 5% groups (P < 0.05). Oxidative stress and necrosis correlated with increasing peroxidizability of the accumulated triglycerides. Affymetrix array analysis comparing the 70% OO and 70% CO groups revealed increased antioxidant pathways and lower expression of genes linked to inflammation and fibrosis in the 70% OO group. A second study in which 70% OO diet was overfed for 50 days produced no evidence of progression of injury beyond simple steatosis. These data suggest that dietary fat type strongly influences the progression of NAFLD and that a Mediterranean diet high in olive oil may reduce the risk of NAFLD progressing to nonalcoholic steatohepatitis.

Differential effects of short term feeding of a soy protein isolate diet and estrogen treatment on bone in the pre-pubertal rat

Background

Previous reports suggest that beneficial effects of soy on bone quality are due to the estrogenic actions of isoflavone phytochemicals associated with the protein. However, mechanistic studies comparing the effects of soy diet and estrogens on bone, particularly in rapidly growing animals are lacking.

Methodology and Principal Findings

We studied the effects of short term feeding of soy protein isolate (SPI) on bone in comparison to the effects of 17β-estradiol (E2) in pre-pubertal rats. Female rats were weaned to one of 4 treatments: 1) a control casein-based diet (CAS); 2) CAS with subcutaneous E2 (10 µg/kg/d) (CAS+E2); 3) a SPI-containing diet (SPI); or 4) SPI with subcutaneous E2 (SPI) or SPI with 10 µg/kg/d E2 (SPI+E2) for 14 days beginning on postnatal day 20. SPI increased while E2 decreased bone turnover compared to CAS. In contrast, both treatments decreased serum sclerostin levels. Microarray analysis of RNA isolated from bone revealed 652 genes regulated by SPI, 491 genes regulated by E2, and 266 genes regulated by both SPI diet and E2 compared to CAS. The expression of caveolin-1, a protein localized in the cell membrane, was down-regulated (p<0.05) in rats fed SPI, but not by E2 compared to rats fed casein. Down-regulation of caveolin-1 by SPI was associated with increased BMP2, Smad and Runx2 expression in bone and osteoblasts (p<0.05).

Conclusions/Significance

These results suggest SPI and E2 have different effects on bone turnover prior to puberty. Approximately half of the genes are regulated in the same direction by E2 or SPI, but in combination, SPI blocks the estrogen effects and returns the profile towards control levels. In addition, there are E2 specific and SPI-specific gene changes related to regulation of bone formation.

Distraction osteogenesis in TNF receptor 1 deficient mice is protected from chronic ethanol exposure

Distraction osteogenesis (DO) is an orthopedic protocol, which induces direct new bone formation as a result of the stimulating effects of mechanical distraction. Chronic ethanol exposure has been demonstrated to inhibit bone formation in rodent models of DO. Further, it has been demonstrated that (1) tumor necrosis factor-α (TNF) blockers are protective against ethanol exposure and (2) recombinant mouse TNF (rmTNF) inhibits direct bone formation in ethanol naïve mice through TNF receptor 1 (TNFR1). These results suggest that the inhibitory effects are significantly mediated by TNF signaling. Therefore, we hypothesized that direct new bone formation in TNFR1 knockout (KO) mice would be protected from ethanol exposure. We used a unique model of mouse DO combined with liquid/chow diets to compare the effects of ethanol on both a strain of TNFR1 knockout (TNFR1 KO) mice and on mice of their C57BL/6 (B6) control strain. In the B6 study, and in concordance with previous work, both radiological and histological analyses of direct bone formation in the distraction gaps demonstrated significant osteoinhibition due to ethanol compared with chow- or pair-fed mice. In the TNFR1 KO study and in support of the hypothesis, both radiological and histological analyses of distraction gap bone formation demonstrated no significant differences between the ethanol, chow fed, or pair fed. We conclude that exogenous rmTNF and ethanol-induced endogenous TNF act to inhibit new bone formation during DO by signaling primarily through TNFR1.

Formula feeding alters hepatic gene expression signature, iron and cholesterol homeostasis in the neonatal pig

In the U.S. formula feeding remains more popular than breast-feeding. In the current study, neonatal piglets were breast fed and compared with those fed commercially available milk-based formula (milk) or soy-based formula (soy) from postnatal day 2 (PND2) until death at PND21 (the usual age of weaning). Liver weights were greater in formula-fed piglets ( P < 0.05) than in breast-fed piglets ( P < 0.05). Affymetrix array analysis revealed significant differences in hepatic gene expression signatures between piglets fed breast milk or formula, as well as between piglets fed milk or soy. In males, expression of 346 hepatic genes differed between formula-fed and breast-fed piglets, and soy-fed differed from milk-fed piglets in 277 genes. Furthermore, gene expression profiles of males differed from females, even when the same diet was consumed. Serum cholesterol was lower in piglets fed formula relative to breast-fed piglets ( P < 0.05), and this was associated with elevations in mRNA encoding cholesterol 7α-hydroxylase (CYP7A1). Consistent with the human literature, breast-fed piglets had lower hepatic iron accumulation than formula-fed piglets. Hepcidin, a major regulator of hepatic iron trafficking, was elevated in piglets fed formula relative to breast-fed piglets ( P < 0.05). Female piglets fed soy formula had increased expression of CYP3A enzymes ( P < 0.05), and soy formula feeding decreased expression of several hepatic genes considered estrogen inducible. These data suggest that: 1) gene expression profiles in neonates differ significantly depending on the diet consumed, 2) hepatic iron storage and cholesterol metabolism clearly differ between breast and formula feeding in piglets, 3) there is no evidence that soy is estrogenic in neonatal pig liver.

Inhibition of fetal bone development through epigenetic down-regulation of HoxA10 in obese rats fed high-fat diet

Epidemiological studies show that maternal obesity during intrauterine and early postnatal life increases the risk of low bone mass and fracture later in life. Here, we show that bone development is inhibited in gestational embryonic day 18.5 (E18.5) embryos from rat dams made obese by feeding a high-fat diet (HFD). Moreover, fetal rat osteogenic calvarial cells (FOCCs) from these obese dams have significantly less potential to develop into mature osteoblasts compared to cells from AIN-93G diet-fed controls. Profiling of transcriptional genes for osteogenesis revealed a profound decrease in the homeodomain-containing factor A10 (HoxA10) in FOCCs from fetuses of HFD-induced obese dams. Significant methylation of the HoxA10 promoter was found in those FOCCs, as well as in mouse ST2 cells treated with a mixture of free fatty acids similar to that found in serum from HFD-induced obese rats. This was accompanied by lower expression of osteogenic markers, but higher levels of PPARγ. Control FOCCs depleted of the HoxA10 gene (shRNA) ex vivo behave similarly to cells from fetuses of obese dams; conversely, overexpression of HoxA10 gene in FOCCs from HFD rats exhibit the same phenotype as controls. Treatment of FOCCs from control rats or of ST2 cells with an artificial mixture of free fatty acids significantly down-regulated HoxA10 protein expression, and cells exhibited adipocyte-like properties. These results suggest that maternal obesity impairs fetal skeletal development through down-regulation of the HoxA10 gene, which may lead to an increase in the prevalence of low bone mass in the offspring later in life.

Maternal obesity promotes a proinflammatory signature in rat uterus and blastocyst

Maternal obesity at conception increases the risk of offspring obesity, thus propagating an intergenerational vicious cycle. Male offspring born to obese dams are hyperresponsive to high fat-diets, gaining greater body weight, fat mass, and additional metabolic sequelae compared to lean controls. In this report, we identify the impact of maternal obesity before conception, on the embryo, and intrauterine milieu during the periimplantation period. We conducted global transcriptomic profiling in the uterus and periimplantation blastocyst, gene/protein expression analyses of inflammatory pathways in conjunction with endocrine and metabolic characterization in the dams at implantation. Uterine gene expression profiles of lean and obese dams revealed distinct signatures for genes regulating inflammation and lipid metabolism. Both pathway and gene-set enrichment analysis revealed uterine nuclear factor-κB and c-Jun N-terminal kinase signaling to be up-regulated in the uterus of obese dams, which was confirmed via immunoblotting. Obese uteri also evidenced an inflammatory secretome with higher chemokine mRNA abundance (CCL2, CCL5, CCL7, and CxCL10) and related regulators (TLR2, CD14, and Ccr1). Increased inflammation in the uterus was associated with ectopic lipid accumulation and expression of lipid metabolic genes. Gene expression in sex-identified male periimplantation blastocyst at day postcoitum 4.5 was clearly influenced by maternal obesity (359 transcripts, ±1.4-fold), including changes in developmental and epigenetic regulators. Akin to the uterus, nuclear factor-κB-regulated proinflammatory genes (CCL4 and CCL5) increased and expression of antioxidant (GPx3) and mitochondrial (TFAM and NRF1) genes decreased in the obese embryos. Our results suggest that ectopic lipid and inflammation may link maternal obesity to increased predisposition of offspring to obesity later in life.

Feeding blueberry diets in early life prevent senescence of osteoblasts and bone loss in ovariectomized adult female rats

BACKGROUND

Appropriate nutrition during early development is essential for maximal bone mass accretion; however, linkage between early nutrition, childhood bone mass, peak bone mass in adulthood, and prevention of bone loss later in life has not been studied.

METHODOLOGY AND PRINCIPAL FINDINGS

In this report, we show that feeding a high quality diet supplemented with blueberries (BB) to pre-pubertal rats throughout development or only between postnatal day 20 (PND20) and PND34 prevented ovariectomy (OVX)-induced bone loss in adult life. This protective effect of BB is due to suppression of osteoblastic cell senescence associated with acute loss of myosin expression after OVX. Early exposure of pre-osteoblasts to serum from BB-fed rats was found to consistently increase myosin expression. This led to maintenance osteoblastic cell development and differentiation and delay of cellular entrance into senescence through regulation of the Runx2 gene. High bone turnover after OVX results in insufficient collagenous matrix support for new osteoblasts and their precursors to express myosin and other cytoskeletal elements required for osteoblast activity and differentiation.

CONCLUSIONS/SIGNIFICANCE

These results indicate: 1) a significant prevention of OVX-induced bone loss from adult rats can occur with only 14 days consumption of a BB-containing diet immediately prior to puberty; and 2) the molecular mechanisms underlying these effects involves increased myosin production which stimulates osteoblast differentiation and reduces mesenchymal stromal cell senescence.

Effects of nutrition and alcohol consumption on bone loss

It is well established that excessive consumption of high-fat diets results in obesity. However, the consequences of obesity on skeletal development, maturation, and remodeling have been the subject of controversy. New studies suggest that the response of the growing skeleton to mechanical loading is impaired and trabecular bone mass is decreased in obesity and after high-fat feeding. At least in part, this occurs as a direct result of inhibited Wnt signaling and activation of peroxisome proliferator-activated receptor-γ (PPAR-γ) pathways in mesenchymal stem cells by fatty acids. Similar effects on Wnt and PPAR-γ signaling occur after chronic alcohol consumption as the result of oxidative stress and result in inhibited bone formation accompanied by increased bone marrow adiposity. Alcohol-induced oxidative stress as the result of increased NADPH-oxidase activity in bone cells also results in enhanced RANKL-RANK signaling to increase osteoclastogenesis. In contrast, consumption of fruits and legumes such as blueberries and soy increase bone formation. New data suggest that Wnt and bone morphogenetic protein signaling pathways are the molecular targets for bone anabolic factors derived from the diet.

Lipid fatty acid profile analyses in liver and serum in rats with nonalcoholic steatohepatitis using improved gas chromatography-mass spectrometry methodology

Fatty acids (FAs) are essential components of lipids and exhibit important biological functions. The analyses of FAs are routinely carried out by gas chromatography-mass spectrometry after multistep sample preparation. In this study, several key experimental factors were carefully examined, validated, and optimized to analyze free fatty acid (FFA) and FA profiles of triglycerides and phospholipids in serum or tissue samples. These factors included (1) methylation/transesterification reagents, (2) validation of internal standards, and (3) final step concentration of FA methyl esters. This new method was utilized to analyze FFAs and the FA profiles of triglycerides and phospholipids in the serum and liver from a recently established rat model of nonalcoholic steatohepatitis (NASH). In this model, rats were fed a 220 kcal kg (-3/4) day (-1) diet containing either 5 or 70% corn oil for 21 days using total enteral nutrition. FA compositions of the serum and liver were found to shift from a pattern dominated by saturated and monounsaturated FAs (C16:0/18:1) to one dominated by polyunsaturated C18:2 derived from dietary linoleic acid. Alteration of FA composition in liver after overfeeding of high polyunsaturated fat diets may contribute to the progression of pathological changes from steatosis to inflammation, necrosis, and fibrosis observed in NASH.

Enhanced expression and glucocorticoid-inducibility of hepatic cytochrome P450 3A involve recruitment of the pregnane-X-receptor to promoter elements in rats fed soy protein isolate

Previous studies and Expt. 1 of the current study demonstrate that diets made with soy protein isolate (SPI) enhance the glucocorticoid-inducibility of hepatic cytochrome P450 (CYP)3A-dependent monooxygenase activities (P < 0.05) compared with diets made with casein (CAS). To determine the underlying molecular mechanism, in a second experiment, we analyzed the time course of dexamethasone (DEX)-induction of hepatic CYP3A mRNA expression on postnatal d (PND) 25 and PND60 in male and female rats fed SPI- or CAS-based diets. After 50 mg(/)kg DEX, CYP3A1 mRNA expression increased >200-fold in SPI-fed males and females at PND25 compared with a 100-fold increase in CAS-fed rats (P < 0.05). The DEX-induced increase in CYP3A1 mRNA in SPI-fed rats on PND60 was also greater than that in CAS-fed rats. The induction by DEX of CYP3A2 mRNA was 1- to 3-fold greater in rats fed SPI compared with those fed CAS on PND25 (P < 0.05). Quantitation of newly synthesized CYP3A1 RNA transcripts by nuclear run-on analysis demonstrated a greater rate of basal transcription in SPI-fed compared with CAS-fed rats on PND60 accompanied by greater binding of the pregnane X receptor (PXR) to a response element on the CYP3A1 promoter in SPI-fed compared with CAS-fed rats (P < 0.05). These data suggest that increased hepatic CYP3A expression and inducibility following SPI feeding involves recruitment of PXR to its response element and suggests that soy consumption has potential effects on metabolism and transport of a wide variety of drugs and on bile acid homeostasis via proteins regulated by this transcription factor.

Effects of long-term ethanol administration in a rat total enteral nutrition model of alcoholic liver disease

Male Sprague-Dawley rats were chronically fed a high-unsaturated-fat diet for 130 days by using total enteral nutrition (TEN), or the same diet in which ethanol (EtOH) isocalorically replaced carbohydrate calories. Additional groups were supplemented with the antioxidant N-acetylcysteine (NAC) at 1.7 g·kg(-1)·day(-1). Relative to an ad libitum chow-fed group, the high-fat-fed controls had three- to fourfold greater expression of fatty acid transporter CD36 mRNA and developed mild steatosis but little other hepatic pathology. NAC treatment resulted in increased somatic growth relative to controls (4.0 ± 0.1 vs. 3.1 ± 0.1 g/day) and increased hepatic steatosis score (3.5 ± 0.6 vs. 2.7 ± 1.2), associated with suppression of the triglyceride hydrolyzing protein adiponutrin, but produced no elevation in serum alanine aminotransferase (ALT). Chronic EtOH treatment increased expression of fatty acid transport protein FATP-2 mRNA twofold, resulting in marked hepatic steatosis, oxidative stress, and a twofold elevation in serum ALT. However, no changes in tumor necrosis factor-α or transforming growth factor-β expression were observed. Fibrosis, as measured by Masson's trichrome and picrosirius red staining, and a twofold increase in expression of type I and type III collagen mRNA, was only observed after EtOH treatment. Long-term EtOH treatment increased hepatocyte proliferation but did not modify the hepatic mRNAs for hedgehog pathway ligands or target genes or genes regulating epithelial-to-mesenchymal transition. Although the effects of NAC on EtOH-induced fibrosis could not be fully evaluated, NAC had additive effects on hepatocyte proliferation and prevented EtOH-induced oxidative stress and necrosis, despite a failure to reverse hepatic steatosis.