Decreased FABP5 and DSG1 protein expression following PAX6 knockdown of differentiated human limbal epithelial cells.

PAX6 haploinsufficiency related aniridia is characterized by disorder of limbal epithelial cells (LECs) and aniridia related keratopathy. In the limbal epithelial cells of aniridia patients, deregulated retinoic acid (RA) signaling components were identified. We aimed to visualize differentiation marker and RA signaling component expression in LECs, combining a differentiation triggering growth condition with a small interfering RNA (siRNA) based aniridia cell model (PAX6 knock down). Primary LECs were isolated from corneoscleral rims of healthy donors and cultured in serum free low Ca2+ medium (KSFM) and in KSFM supplemented with 0.9 mmol/L Ca2+. In addition, LECs were treated with siRNA against PAX6. DSG1, PAX6, KRT12, KRT 3, ADH7, RDH10, ALDH1A1, ALDH3A1, STRA6, CYP1B1, RBP1, CRABP2, FABP5, PPARG, VEGFA and ELOVL7 expression was determined using qPCR and western blot. DSG1, FABP5, ADH7, ALDH1A1, RBP1, CRABP2 and PAX6 mRNA and FABP5 protein expression increased (p ≤ 0.03), PPARG, CYP1B1 mRNA expression decreased (p ≤ 0.0003) and DSG1 protein expression was only visible after Ca2+ supplementation. After PAX6 knock down and Ca2+ supplementation, ADH7 and ALDH1A1 mRNA and DSG1 and FABP5 protein expression decreased (p ≤ 0.04), compared to Ca2+ supplementation alone. Using our cell model, with Ca2+ supplementation and PAX6 knockdown with siRNA treatment against PAX6, we provide evidence that haploinsufficiency of the master regulatory gene PAX6 contributes to differentiation defect in the corneal epithelium through alterations of RA signalling. Upon PAX6 knockdown, DSG1 differentiation marker and FABP5 RA signaling component mRNA expression decreases. A similar effect becomes apparent at protein level though differentiation triggering Ca2+ supplementation in the siRNA-based aniridia cell model. Expression data from this cell model and from our siRNA aniridia cell model strongly indicate that FABP5 expression is PAX6 dependent. These new findings may lead to a better understanding of differentiation processes in LECs and are able to explain the insufficient cell function in AAK.

L-carnitine extenuates endocrine disruption, inflammatory burst and oxidative stress in carbendazim-challenged male rats via upregulation of testicular StAR and FABP9, and downregulation of P38-MAPK pathways.

We have addressed in the current study the potential of L-carnitine (LC) to extenuate the reproductive toxic insults of carbendazim (CBZ) in male rats, and the molecular mechanisms whereby carnitine would modify the spermatogenic and steroidogenic derangements invoked by the endocrine disruptor. Herein, animals received daily doses of carbendazim (100 mg/kg) by gavage for 8 weeks. Another CBZ-challenged group was co-supplemented with LC (500 mg/kg, IP) twice weekly for 8 weeks. Sperm quantity and quality (morphology, motility and viability), serum testosterone and gonadotropins, and thyroid hormone levels were assessed. Serum tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6) and interleukin-10 (IL-10) concentrations were determined by ELISA. Oxidant/antioxidant status in rat testis was investigated via measuring testicular contents of malondialdehyde (MDA) and reduced glutathione (GSH), as well as the activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx). Immunohistochemical localizations of the junctional protein; occludin, and inflammatory markers; inducible nitric oxide synthase (iNOS) and nuclear factor kappa beta (NF-κB) were further analyzed. A host of transduction genes that regulate spermatogenic and steroidogenic pathways, and their encoded proteins namely, Steroidogenic Acute Regulatory Protein (StAR), Fatty acid binding protein 9 (FABP9) and P38-mitogen activated protein kinase (P38-MAPK) were assessed by real time quantitative (RT-qPCR) and Western blot. LC improved rat spermiogram, testicular histological alterations and endocrine perturbances, and modulated genes' expressions and their respective proteins. In conclusion, LC effects appear to reside for the most part on its endocrine-preserving, anti-oxidant and anti-inflammatory properties through a myriad of interlaced signal transductions that ultimately recapitulated its beneficial effects on spermatogenesis and steroidogenesis.

Expression and enhancement of FABP4 in septoclasts of the growth plate in FABP5-deficient mouse tibiae.

In our previous study, fatty acid-binding protein 5 (FABP5) was expressed in septoclasts with long processes which are considered to resorb uncalcified matrix of the growth plate (GP) cartilage, and no apparent abnormalities were detected in the histo-architecture of the GP of FABP5-deficient (FABP5-/-) mice. Those finding lead us to hypothesize that another FABP can compensate the deletion of FABP5 in septoclasts of its gene-mutant mice. Based on the hypothesis, the present study examined the expression levels of several other FABPs in septoclasts and their morphology in FABP5-/- mouse tibiae. Processes of FABP5-/- septoclasts tend to be shorter than wild septoclasts. FABP4-positive septoclasts in FABP5-/- mice were more numerous than those cells in wild mice.Peroxisome proliferator-activated receptor (PPAR) γ was expressed in FABP4-positive septoclasts of FABP5-/- mice as well as mice administered with GW1929, a PPARγ agonist, suggesting that the occurrence of PPARγ induces an increase of FABP4-positive septoclasts. The present finding suggests that the functional exertion of FABP5 in septoclasts is supplemented by FABP4 in normal and FABP5-/- mice, and that the expression of FABP4 is up-regulated in accompany with PPARγ in FABP5-/- for maintenance of resorptive activity in the GP.

Fatty Acid-binding Protein 4 Expression in Tumor Cells as a Potential Marker for Anaplastic Meningiomas.

Meningiomas are highly vascularized tumors originating from arachnoid cap cells of the leptomeninges. The majority of meningiomas are classified as World Health Organization (WHO) grade I and display a benign clinical course with a low risk of recurrence. In contrast, WHO grade III meningiomas carry a high risk of recurrence and poor prognosis. However, it is commonly recognized that histopathologic grading does not always reliably predict recurrence or progression of meningiomas. Fatty acid-binding protein 4 (FABP4) is a small molecular weight lipid chaperone that plays a proangiogenic role in vascular endothelial cells. FABP4 is not expressed in normal brain vasculature but is detected in some glioblastoma and arteriovenous malformations. The expression pattern of FABP4 in meningiomas have not been reported to date. We analyzed FABP4 expression in a cohort of paraffin-embedded meningioma specimens by immunohistochemistry and double immunofluorescence analyses. FABP4 expression was detected in a subset of endothelial cells in 47 of 48 meningioma samples analyzed. Interestingly, tumor cell-FABP4 expression was also detected in only 1 of 22 grade I, none of grade II, but 10 of 12 grade III meningiomas (P<0.0001). These results demonstrate that FABP4 is commonly expressed in meningioma vascular endothelial cells while tumor cell expression of FABP4 is primarily observed in anaplastic meningiomas. A combination of FABP4 immunostaining with histopathologic grading might provide a more accurate prediction of the biological behavior of meningiomas than histopathologic grading alone.

Analysis of CRABP2 and FABP5 genes in primary and recurrent pterygium tissues.

The etiology of pterygium remains unclear, but ultraviolet (UV) radiation is generally considered to be major risk factor. Pterygium has similarity features with many cancers, including inflammation, invasion, cell proliferation, anti-apoptosis, angiogenesis and recurrence after resection. Retinoic acid via cellular retinoic acid binding protein 2 (CRABP2) is involved in cell cycle arrest, apoptosis and differentiation, while it via fatty acid binding protein 5 (FABP5) is involved in survival, cell proliferation and angiogenesis, which pathway gets activated depends on the CRABP2/FABP5 ratio. Alterations of retinoid signaling were found in many cancer types. The deregulated retinoid signaling may also contribute to the development and/or recurrence of pterygium. The aim of our study was to determine mRNA and protein expressions of CRABP2 and FABP5 and ratio of CRABP2/FABP5 in primer and recurrent pterygium tissues. Pterygia tissues were collected from 30 eyes of 30 patients undergoing pterygium excision. CRABP2 and FABP5 mRNA and protein expression were assessed using Real-time PCR and Western blotting through examination of excised specimens from pterygium and conjunctiva tissues. The ratio of CRABP2/FABP5 gene expression was not altered when primary pterygium tissues compared normal conjunctival tissues (1.00-fold change). Whereas the ratio of CRABP2/ FABP5 gene expression was decreased when recurrent pterygium tissues compared normal conjunctival tissues (0.81-fold change). Understanding etiopathogenesis of pterygium may aid in the find of more promising treatments to prevent pterygium in earlier stages.

Two fatty acid-binding proteins expressed in the intestine interact differently with endocannabinoids.

Two different members of the fatty acid-binding protein (FABP) family are found in enterocyte cells of the gastrointestinal system, namely liver-type and intestinal fatty acid-binding proteins (LFABP and IFABP, also called FABP1 and FABP2, respectively). Striking phenotypic differences have been observed in knockout mice for either protein, for example, high fat-fed IFABP-null mice remained lean, whereas LFABP-null mice were obese, correlating with differences in food intake. This finding prompted us to investigate the role each protein plays in directing the specificity of binding to ligands involved in appetite regulation, such as fatty acid ethanolamides and related endocannabinoids. We determined the binding affinities for nine structurally related ligands using a fluorescence competition assay, revealing tighter binding to IFABP than LFABP for all ligands tested. We found that the head group of the ligand had more impact on binding affinity than the alkyl chain, with the strongest binding observed for the carboxyl group, followed by the amide, and then the glycerol ester. These trends were confirmed using two-dimensional 1 H-15 N nuclear magnetic resonance (NMR) to monitor chemical shift perturbation of the protein backbone resonances upon titration with ligand. Interestingly, the NMR data revealed that different residues of IFABP were involved in the coordination of endocannabinoids than those implicated for fatty acids, whereas the same residues of LFABP were involved for both classes of ligand. In addition, we identified residues that are uniquely affected by binding of all types of ligand to IFABP, suggesting a rationale for its tighter binding affinity compared with LFABP.

New Insights into Apolipoprotein A5 and the Modulation of Human Adipose-derived Mesenchymal Stem Cells Adipogenesis.

BACKGROUND: The hallmark of obesity is the excessive accumulation of triglyceride (TG) in adipose tissue. Apolipoprotein A5 (ApoA5) has been shown to influence the prevalence and pathogenesis of obesity. However, the underlying mechanisms remain to be clarified. METHODS: Human adipose-derived mesenchymal stem cells (AMSCs) were treated with 600 ng/ml human recombinant ApoA5 protein. The effect of ApoA5 on intracellular TG content and adipogenic related factors expression were determined. Furthermore, the effect of ApoA5 on CIDE-C expression was also observed. RESULTS: During the process of adipogenesis, ApoA5 treatment reduced the intracellular accumulation of lipid droplets and the TG levels; meanwhile, ApoA5 down-regulated the expression levels of adipogenic related factors, including CCAAT enhancer-binding proteins α/ß (C/EBPα/ß), fatty acid synthetase (FAS), and fatty acid-binding protein 4 (FABP4). Furthermore, the suppression of adipogenesis by ApoA5 was mediated through the inhibition of CIDE-C expression, an important factor which promotes the process of adipogenesis. However, over-expressing intracellular CIDE-C could lead to the loss-of-function of ApoA5 in inhibiting AMSCs adipogenesis. CONCLUSIONS: In conclusion, ApoA5 inhibits the adipogenic process of AMSCs through, at least partly, down-regulating CIDE-C expression. The present study provides novel mechanisms whereby ApoA5 prevents obesity via AMSCs in humans.

Developmental exposure to a human relevant mixture of endocrine disruptors alters metabolism and adipogenesis in zebrafish (Danio rerio).

Exposure to endocrine disrupting chemicals has been suggested to contribute to the ongoing globally increasing obesity trend. The complex chemical mixtures that humans and wildlife are exposed to include a number of compounds that may have obesogenic properties. In this study we examined a mixture consisting of phthalate-monoesters, triclosan, and perfluorinated compounds. The mixture was designed within the EDC-MixRisk project based on serum levels of the compounds in pregnant women of a Swedish mother-child cohort. The compounds were negatively associated with birth weight of the children. We assessed whether developmental exposure to this mixture in combination with a calorie-rich diet affected metabolic rate, blood lipids, adipogenesis and lipid storage, and the whole-body level of neutral lipids in zebrafish (Danio rerio). Wildtype zebrafish were exposed to the mixture from 3 h post fertilization to 5, 14 or 17 days post fertilization (dpf) at water concentrations corresponding to 1, 10, 20, or 100 times the geometrical mean of the serum concentration (hsc) in the women. Exposure to the mixture at 20 times hsc lowered metabolic rate at 2-5 dpf, and increased the number of adipocytes and the amount of visceral adipose tissue at 14 and 17 dpf respectively. Also, mRNA expression of fatty acid binding protein 11a was increased at 17 dpf by 10 and 20 times hsc of the mixture. This study shows that a human-relevant mixture of environmental pollutants affects metabolic rate, adipogenesis and lipid storage in young zebrafish fed a calorie-rich diet, thus demonstrating its potential to disrupt metabolism.

FABP4 and MMP9 levels identified as predictive factors for poor prognosis in patients with nonalcoholic fatty liver using data mining approaches and gene expression analysis.

Nonalcoholic fatty liver (NAFLD) may progress to nonalcoholic steatohepatitis (NASH) and ultimately to cirrhosis and hepatocellular carcinoma (HCC). Prognostic markers for these conditions are poorly defined. The aim of this study was to identify predictive gene markers for the transition from NAFL to NASH and then to poorer conditions. Gene expression omnibus datasets associated with a prediction analysis algorithm were used to create a matrix composed of control subject (n = 52), healthy obese (n = 51), obese with NAFL (n = 42) and NASH patients (n = 37) and 19,085 genes in order to identify specific genes predictive of the transition from steatosis to NASH and from NASH to cirrhosis and HCC and thus patients at high risk of complications. A validation cohort was used to validate these results. We identified two genes, fatty acid binding protein-4 (FABP4) and matrix metalloproteinase-9 (MMP9), which respectively allowed distinguishing patients at risk of progression from NAFL to NASH and from NASH to cirrhosis and HCC. Thus, NAFL patients expressing high hepatic levels of FABP4 and NASH patients expressing high hepatic levels of MMP9 are likely to experience disease progression. Therefore, using FABP4 and MMP9 as blood markers could help to predict poor outcomes and/or progression of NAFL during clinical trial follow-up.

Impact of the route of nutrition on gut mucosa in ventilated adults with shock: an ancillary of the NUTRIREA-2 trial.

PURPOSE: The effects of the route of nutrition on the gut mucosa of patients with shock are unclear. Plasma citrulline concentration is a marker of enterocyte mass, and plasma intestinal fatty acid binding protein (I-FABP) concentration is a marker of enterocyte damage. We aimed to study the effect of the route of nutrition on plasma citrulline concentration measured at day 3 of nutrition. MATERIALS AND METHODS: Ancillary study of the NUTRIREA-2 trial. Ventilated adults with shock were randomly assigned to receive enteral or parenteral nutrition. Enterocyte biomarkers were measured at baseline, day 3, and day 8 of nutrition. RESULT: A total of 165 patients from 13 French ICUs were included in the study: 85 patients in the enteral group and 80 patients in the parenteral group. At baseline, plasma citrulline was low without difference between groups (12.2 µmol L-1 vs 13.3 µmol L-1). At day 3, plasma citrulline concentration was higher in the enteral group than in the parenteral group (18.7 µmol L-1 vs 15.3 µmol L-1, p = 0.01). Plasma I-FABP concentration was increased at baseline, without difference between groups (245 pg mL-1 vs 244 pg mL-1). Plasma I-FABP concentration was higher in the enteral group than in the parenteral group at day 3 and day 8 (158 pg mL-1 vs 50 pg mL-1, p = 0.005 and 225 pg mL-1 vs 50 pg mL-1, p = 0.03). CONCLUSION: Plasma citrulline concentration was higher after 3 days of enteral nutrition than after 3 days of parenteral nutrition. This result raises the question of the possibility that enteral nutrition is associated with a more rapid restoration of enterocyte mass than parenteral nutrition.

Prognostic significance of fatty acid binding protein-4 in the invasive ductal carcinoma of the breast.

We conducted this study to identify clinico-pathologic and prognostic factors that are associated with fatty acid binding protein-4 (FABP4) and to discuss its therapeutic potentials in patients with breast cancer (BC). In a total of 75 patients with an established diagnosis of invasive ductal carcinoma of the breast, we performed a retrospective analysis of the medical records and analyzed their immunohistochemical findings. Following evaluation of baseline and clinico-pathological characteristics such as the age, immunohistochemical expressions of FABP4, TNM stage, tumor grade, lymphatic and perineural invasion, estrogen receptor (ER) and progesterone receptor (PR), disease-free survival (DFS), overall survival (OS), recurrence and death, we analyzed correlations of the expression of FABP4 with clinico-pathologic and prognostic factors. Our results showed that tumor grade and recurrence had a significant correlation with the expression of FABP4 (P = 0.002 and 0.049, respectively). Moreover, we also found that the DFS had a significant correlation with the expression of FABP4 (P = 0.049). It can therefore be concluded that the expression of FABP4 might have a prognostic value in patients with BC. But further studies are warranted to establish its potentials as a prognostic indicator.

Cloning of fatty acid-binding protein 2 (fabp2) in loach (Misgurnus anguillicaudatus) and its expression in response to dietary oxidized fish oil.

Fatty acid-binding protein 2 (FABP2) is involved in the uptake of dietary fatty acids and intracellular fatty acid transport. In the present study, cDNA of fabp2 in loach (Misgurnus anguillicaudatus) was cloned and its full length was 956 bp, encoding 134 amino acids. Gene expression of fabp2 was investigated in different development stages and different tissues of loach, showing that the expression of fabp2 was recorded at 2 days after hatching (DAH), 10DAH, 20DAH and 35DAH, and higher in loach intestine, muscle and brain, compared with other tissues. We also investigated the effects of dietary oxidized fish oil (OFO) on the expression of intestinal fabp2 in loach juveniles by using fluorescence in situ hybridization (FISH) and real-time quantitative PCR. Fabp2 gene was expressed mainly by the intestinal epithelium cells of loach juveniles. The expression of intestinal fabp2 in loaches fed with OFO diet was significantly up-regulated on day 1 and 3, and down-regulated on day 10 after feeding, compared with those loaches fed with dietary fresh fish oil (FO), which were in accordance with the fluorescence intensities of FISH exhibiting in the corresponding feeding time. The present study indicated that dietary oxidized fish oil could affect the expression of fabp2 in the loach. Our results serve as reference to better understand the functional characterization of fabp2 in loach and other fish species.

Down-regulation of A-FABP predicts non-muscle invasive bladder cancer progression: investigation with a long term clinical follow-up.

BACKGROUND: Non-muscle invasive bladder cancers (NMIBC: pTa, pT1) are characterised by a high risk of recurrence and/or progression. Identification of prognostic markers is needed to improve both diagnosis and management of the disease. The aim of this study was to analyse the expression of A-FABP (adipocyte-fatty acid binding protein) and to evaluate its prognostic value in bladder cancer with a long term clinical follow-up. METHODS: A-FABP expression was investigated by immunohistochemistry in 236 tumours (114 pTa, 61 pT1, 61 pT2-4). Immunostaining was classified as negative (absent or weak immunostaining and moderate or strong staining on ≤10% of cells) or positive (moderate or strong staining on > 10% of cells). Event-free survival (EFS) and overall survival (OS) were determined with a 87.3 months median follow-up in the overall cohort. Recurrence-free survival (RFS) and progression-free survival (PFS) were established in NMIBC. RESULTS: Loss of A-FABP was associated with higher mean age, high stage/grade, and the presence of metastatic lymph nodes. It was correlated with shorter median EFS (17.5 vs 62.5 months; p = 0.001) and mean OS (76.7 vs 154.2 months; p = 0.009) and with higher risk of progression in the pTa/pT1 subgroup (HR, 0.36; 95% CI, 0.13-0.96; p = 0.041) and importantly in the pTa tumours (HR, 0.34; 95% CI, 0.10-0.97; p = 0.045). CONCLUSION: These results demonstrated that loss of A-FABP expression following a long follow-up was predictive of pTa and pTa/pT1 progression. Immunohistochemistry on diagnostic biopsy is easy to use and could be of value to help clinicians to propose appropriate treatment for these tumours.

An in vitro approach for prioritization and evaluation of chemical effects on glucocorticoid receptor mediated adipogenesis.

Rising obesity rates worldwide have socio-economic ramifications. While genetics, diet, and lack of exercise are major contributors to obesity, environmental factors may enhance susceptibility through disruption of hormone homeostasis and metabolic processes. The obesogen hypothesis contends that chemical exposure early in development may enhance adipocyte differentiation, thereby increasing the number of adipocytes and predisposing for obesity and metabolic disease. We previously developed a primary human adipose stem cell (hASC) assay to evaluate the effect of environmental chemicals on PPARG-dependent adipogenesis. Here, the assay was modified to determine the effects of chemicals on the glucocorticoid receptor (GR) pathway. In differentiation cocktail lacking the glucocorticoid agonist dexamethasone (DEX), hASCs do not differentiate into adipocytes. In the presence of GR agonists, adipocyte maturation was observed using phenotypic makers for lipid accumulation, adipokine secretion, and expression of key genes. To evaluate the role of environmental compounds on adipocyte differentiation, progenitor cells were treated with 19 prioritized compounds previously identified by ToxPi as having GR-dependent bioactivity, and multiplexed assays were used to confirm a GR-dependent mode of action. Five chemicals were found to be strong agonists. The assay was also modified to evaluate GR-antagonists, and 8/10 of the hypothesized antagonists inhibited adipogenesis. The in vitro bioactivity data was put into context with extrapolated human steady state concentrations (Css) and clinical exposure data (Cmax). These data support using a human adipose-derived stem cell differentiation assay to test the potential of chemicals to alter human GR-dependent adipogenesis.

Differential Fatty Acid-Binding Protein Expression in Persistent Radial Glia in the Human and Sheep Subventricular Zone.

Fatty acid-binding proteins (FABPs) are a family of transport proteins that facilitate intracellular transport of fatty acids. Despite abundant expression in the brain, the role that FABPs play in the process of cell proliferation and migration in the subventricular zone (SVZ) remains unclear. Our results provide a detailed characterisation of FABP3, 5, and 7 expression in adult and fetal human and sheep SVZ. High FABP5 expression was specifically observed in the adult human SVZ and co-labelled with polysialylated neural cell adhesion molecule (PSA-NCAM), glial fibrillary acidic protein (GFAP), GFAPδ, and proliferating cell nuclear antigen (PCNA), indicating a role for FABP5 throughout the full maturation process of astrocytes and neuroblasts. Some FABP5+ cells had a radial glial-like appearance and co-labelled with the radial glia markers vimentin (40E-C) and GFAP. In the fetal human brain, FABP5 was expressed by radial glia cells throughout the ventricular zone. In contrast, radial glia-like cells in sheep highly expressed FABP3. Taken together, these differences highlight the species-specific expression profile of FABPs in the SVZ. In this study, we demonstrate the distribution of FABP in the adult human SVZ and fetal ventricular zone and reveal its expression on persistent radial glia that may be involved in adult neurogenesis.

Epidermal FABP Prevents Chemical-Induced Skin Tumorigenesis by Regulation of TPA-Induced IFN/p53/SOX2 Pathway in Keratinocytes.

Skin lipids (e.g., fatty acids) are essential for normal skin functions. Epidermal FABP (E-FABP) is the predominant FABP expressed in skin epidermis. However, the role of E-FABP in skin homeostasis and pathology remains largely unknown. Herein, we utilized the 7,12-dimethylbenz(a)anthracene and 12-O-tetradecanolyphorbol-13-acetate-induced skin tumorigenesis model to assess the role of E-FABP in chemical-induced skin tumorigenesis. Compared to their wild-type littermates, mice deficient in E-FABP, but not adipose FABP, developed more skin tumors with higher incidence. 12-O-tetradecanolyphorbol-13-acetate functioning as a tumor promoter induced E-FABP expression and initiated extensive flaring inflammation in skin. Interestingly, 12-O-tetradecanolyphorbol-13-acetate -induced production of IFN-ß and IFN-λ in the skin tissue was dependent on E-FABP expression. Further protein and gene expression arrays demonstrated that E-FABP was critical in enhancing IFN-induced p53 responses and in suppressing SOX2 expression in keratinocytes. Thus, E-FABP expression in skin suppresses chemical-induced skin tumorigenesis through regulation of IFN/p53/SOX2 pathway. Collectively, our data suggest an unknown function of E-FABP in prevention of skin tumor development, and offer E-FABP as a therapeutic target for improving skin innate immunity in chemical-induced skin tumor prevention.

REV-ERB agonism suppresses osteoclastogenesis and prevents ovariectomy-induced bone loss partially via FABP4 upregulation.

REV-ERBs (REV-ERBα and REV-ERBß) are transcription repressors and circadian regulators. Previous investigations have shown that REV-ERBs repress the expression of target genes, including MMP9 and CX3CR1, in macrophages. Because MMP9 and CX3CR1 reportedly participate in receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclastogenesis, we inferred that REV-ERBs might play a role in osteoclastogenesis. In the present study, we found that the REV-ERBα level decreased significantly during RANKL-induced osteoclast differentiation from primary bone marrow-derived macrophages (BMMs). REV-ERBα knockdown by small interfering RNA in BMMs resulted in the enhanced formation of osteoclasts, whereas REV-ERBß knockdown showed no effect on osteoclast differentiation. Moreover, the REV-ERB agonist SR9009 inhibited osteoclast differentiation and bone resorption. Intraperitoneal SR9009 administration prevented ovariectomy-induced bone loss; this effect was accompanied by decreased serum RANKL and C-terminal telopeptide of type I collagen levels and increased osteoprotegerin levels. Further investigation revealed that NF-κB and MAPK activation and nuclear factor of activated T cells, cytoplasmic 1, and c-fos expression were suppressed by SR9009. The level of reactive oxygen species was also decreased by SR9009, with NADPH oxidase subunits also being down-regulated. In addition, an expression microarray showed that FABP4, an intracellular lipid-binding protein, was up-regulated by REV-ERB agonism. BMS309403, an inhibitor of FABP4, partially prevented the suppression of osteoclastogenesis by SR9009 through stabilizing phosphorylation of p65. To summarize, our results proved that the REV-ERB agonism inhibited osteoclastogenesis partially via FABP4 up-regulation.-Song, C., Tan, P., Zhang, Z., Wu, W., Dong, Y., Zhao, L., Liu, H., Guan, H., Li, F. REV-ERB agonism suppresses osteoclastogenesis and prevents ovariectomy-induced bone loss partially via FABP4 upregulation.

Reduced blood-brain barrier expression of fatty acid-binding protein 5 is associated with increased vulnerability of APP/PS1 mice to cognitive deficits from low omega-3 fatty acid diets.

Lower levels of the cognitively beneficial docosahexaenoic acid (DHA) are often observed in Alzheimer's disease (AD) brains. Brain DHA levels are regulated by the blood-brain barrier (BBB) transport of plasma-derived DHA, a process facilitated by fatty acid-binding protein 5 (FABP5). This study reports a 42.1 ± 12.6% decrease in the BBB transport of 14 C-DHA in 8-month-old AD transgenic mice (APPswe,PSEN1∆E9) relative to wild-type mice, associated with a 34.5 ± 6.7% reduction in FABP5 expression in isolated brain capillaries of AD mice. Furthermore, short-term spatial and recognition memory deficits were observed in AD mice on a 6-month n-3 fatty acid-depleted diet, but not in AD mice on control diet. This intervention led to a dramatic reduction (41.5 ± 11.9%) of brain DHA levels in AD mice. This study demonstrates FABP5 deficiency and impaired DHA transport at the BBB are associated with increased vulnerability to cognitive deficits in mice fed an n-3 fatty acid-depleted diet, in line with our previous studies demonstrating a crucial role of FABP5 in BBB transport of DHA and cognitive function.

Heart-type fatty acid binding protein levels in elderly diabetics without known cardiovascular disease.

BACKGROUND: Cardiovascular disease (CVD) is reported to be higher in elderly diabetics. Serum heart-type fatty acid binding protein (H-FABP) is a serum marker of myocardial ischemia. We aimed to investigate the association between serum H-FABP level and conventional cardiovascular risk factors, inflammatory markers and subclinical atherosclerosis in elderly diabetics without overt CVD. PATIENTS AND METHODS: A total of 50 elderly diabetic patients without overt CVD and 30 age-, sex- and body mass index (BMI)-matched healthy controls were enrolled. Anthropometric and biochemical parameters, serum H-FABP, high-sensitivity C-reactive protein (hs-CRP), fibrinogen and carotid intima-media thickness (CIMT) were measured. Logistic regression analyses (adjustments for age, sex, hypertension, smoking, diabetes, BMI, blood pressure, lipid, blood glucose, hemoglobin A1c, hs-CRP and fibrinogen) were performed to evaluate the association between H-FABP and cardiovascular risk factors and atherosclerosis indices. RESULTS: Serum fibrinogen (421.50±85.52 mg/dL vs 319.17±30.77 mg/dL, p=0.023), CIMT (0.70±0.12 mm vs 0.59±0.06 mm, p<0.001) and hs-CRP (5.72±4.50 mg/dL vs 1.60±0.72 mg/dL, p<0.001) were significantly higher in diabetic patients than controls. The mean serum H-FABP level did not differ between groups (1571.79±604.60 ng/mL vs 1500.25±463.35 ng/mL, p=0.905). H-FABP was positively correlated with fibrinogen (r2=0.473, p<0.001), hs-CRP (r2=0.323, p=0.003) and CIMT (r2=0.467, p<0.001). After full adjustments, the serum H-FABP level was independently associated with an increase in the fibrinogen level (odds ratio [OR] =4.21, 95% confidence level [CI] =1.49-11.90). CONCLUSION: Serum H-FABP was similar in the elderly diabetic patients without known CVD when compared with the nondiabetic control group. H-FABP does not possess a high diagnostic value as a cardiovascular marker when used alone; however, it may add supplementary information in patients with a high fibrinogen level.