Hyperandrogenism diminishes maternal-fetal fatty acid transport by increasing FABP4-mediated placental lipid accumulation†.

Long-chain polyunsaturated fatty acids (LCPUFAs) are critical for fetal brain development. Infants born to preeclamptic mothers or those born growth restricted due to placental insufficiency have reduced LCPUFA and are at higher risk for developing neurodevelopmental disorders. Since plasma levels of testosterone (T) and fatty acid-binding protein 4 (FABP4) are elevated in preeclampsia, we hypothesized that elevated T induces the expression of FABP4 in the placenta leading to compromised transplacental transport of LCPUFAs. Increased maternal T in pregnant rats significantly decreased n-3 and n-6 LCPUFA levels in maternal and fetal circulation, but increased their placental accumulation. Dietary LCPUFAs supplementation in T dams increased LCPUFA levels in the maternal circulation and further augmented placental storage, while failing to increase fetal levels. The placenta in T dams exhibited increased FABP4 mRNA and protein levels. In vitro, T dose-dependently upregulated FABP4 transcription in trophoblasts. Testosterone stimulated androgen receptor (AR) recruitment to the androgen response element and trans-activated FABP4 promoter activity, both of which were abolished by AR antagonist. Testosterone in pregnant rats and cultured trophoblasts significantly reduced transplacental transport of C14-docosahexaenoic acid (DHA) and increased C14-DHA accumulation in the placenta. Importantly, FABP4 overexpression by itself in pregnant rats and trophoblasts increased transplacental transport of C14-DHA with no significant placental accumulation. Testosterone exposure, in contrast, inhibited this FABP4-mediated effect by promoting C14-DHA placental accumulation.

Effect of Korean Red Ginseng on metabolic syndrome.

Metabolic syndrome (MS) refers to a clustering of at least three of the following medical conditions: high blood pressure, abdominal obesity, hyperglycemia, low high-density lipoprotein level, and high serum triglycerides. MS is related to a wide range of diseases which includes obesity, diabetes, insulin resistance, cardiovascular disease, dyslipidemia, or non-alcoholic fatty liver disease. There remains an ongoing need for improved treatment strategies for MS. The most important risk factors are dietary pattern, genetics, old age, lack of exercise, disrupted biology, medication usage, and excessive alcohol consumption, but pathophysiology of MS has not been completely identified. Korean Red Ginseng (KRG) refers to steamed/dried ginseng, traditionally associated with beneficial effects such as anti-inflammation, anti-fatigue, anti-obesity, anti-oxidant, and anti-cancer effects. KRG has been often used in traditional medicine to treat multiple metabolic conditions. This paper summarizes the effects of KRG in MS and related diseases such as obesity, cardiovascular disease, insulin resistance, diabetes, dyslipidemia, or non-alcoholic fatty liver disease based on experimental research and clinical studies.

A NMR-based drug screening strategy for discovering active substances from herbal medicines: Using Radix Polygoni Multiflori as example.

ETHNOPHARMACOLOGICAL RELEVANCE: Herbal medicines have always been important sources for new drugs. And developing new drugs from traditional herbal medicine is currently still an effective way. However, screening for active substances from herbal medicines extracts has ever been a challenging topic, due to their intrinsic complexity. The herb Radix Polygoni Multiflori has been used as a tonic and an antiaging herb in Traditional Chinese Medicine. In clinical studies, the extract of Radix Polygoni Multiflori can improve hypercholesterolemia, atherosclerotic, diabetes and other diseases commonly associated with glycolipid metabolism, however, the molecular mechanisms of these actions are unknown. AIM OF THE STUDY: We devised a NMR-based drug screening strategy for discovering active substances from herbal medicines, using Radix Polygoni Multiflori as example to address such challenging topic, meanwhile, to explore molecular target of Radix Polygoni Multiflori's glycolipid metabolism benefit. MATERIALS AND METHODS: Herbal medicines extracts were subjected to moderate separation to generate libraries of pre-purified subfractions, target protein was then added to each subfraction, and ligand-observed NMR experiments (line-broadening experiment, chemical shift perturbations measurements and saturation transfer difference spectrum) were performed, active substances identification and structural optimization were then accomplished using signals provided by ligand-observed NMR interaction detection and HPLC-SPE-NMR. The strategy was demonstrated by discovering an active component from extract of herb Radix Polygoni Multiflori, using human fatty acid binding protein 4 (FABP4) as target protein. RESULTS: 2,4-dihydroxy-6-[(1E)-2-(4-hydroxyphenyl)ethenyl]phenyl-ß-D-glucopyranoside(TSG), the hit from one subfraction, has obvious interaction with target protein FABP4, due to FABP4 is a potential therapeutic target for metabolic diseases such as diabetes and atherosclerosis, the screening result will give clue to the active component and molecular target of Radix Polygoni Multiflori's glycolipid metabolism benefit. Besides, interaction information at atom level offered by ligand-observed NMR experiment would be valuable in the further stage of lead optimization. CONCLUSIONS: The devised NMR-based drug screening strategy can discover active substances from herbal medicines efficiently and precisely, meanwhile, can shed light on molecular mechanism of traditional usage of the herb.

Beneficial Effects of Korean Red Ginseng in the Progression of Non-Alcoholic Steatohepatitis via FABP4 Modulation.

Korean red ginseng (KRG) is a traditional herbal medicine used to prevent several geriatric diseases due to its therapeutic effects on metabolic disorder, including type 2 diabetes and fatty liver disease. In this study, we investigated the effects of KRG on the progression of nonalcoholic steatohepatitis (NASH) in mice. NASH was induced by feeding a methionine- and choline-deficient high-fat or high-fat/high-sucrose diet for 6 or 13 weeks, respectively. Each diet group was also orally administered saline (group G0) or KRG extract (100, 200, or 400 mg/kg/day; groups G1, G2, and G4, respectively). KRG showed anti-inflammatory and antifibrogenic effects in the diet-induced NASH models. Furthermore, the expression levels of lipid metabolism-related genes were markedly decreased with KRG treatment in both diet-induced NASH groups. We next confirmed the expression levels of FABP4 in the liver and its ability to regulate inflammation and/or oxidative stress. We observed decreased levels of FABP4 mRNA and protein in the KRG-treated groups indicating that KRG affects the pathogenesis of NASH-related inflammatory responses by modulating FABP4 expression. Results of in vitro experiments showed similar patterns in cells treated with KRG, indicating that KRG treatment regulates the expression of FABP4 and subsequently reduces NASH related inflammation. Our findings suggest a novel role of KRG in NASH-related inflammatory responses via modulation of FABP4 expression in the liver. KRG may be a safe alternative therapy to prevent NASH progression.

Herbalog: A tool for target-based identification of herbal drug efficacy through molecular docking.

BACKGROUND: Traditionally, molecular docking is primarily employed to screen pure compounds; the top-ranking chemicals are subsequently selected for experimental validation. Unlike synthetic chemicals, most natural products are commercially unavailable. The isolation and purification of each natural product is extremely time-consuming, which has restricted the screening of lead compounds from natural products. PURPOSE: We developed a protocol, Herbalog, to facilitate the identification of bioactive phytochemicals through molecular docking. METHODS: We wrote a script using Python and Autodock Vina for docking; ligand displacement and adipolysis assays were used to determine the anti-fatty acid binding protein (FABP) 4 activity of bioactive extracts. An ultraperformance liquid chromatography quadrupole time-of-flight mass spectrometry system was applied for identifying major peaks of bioactive extracts. RESULTS: Herbalog, a natural product database, contains 5,112 phytochemicals from 197 common herbs and a script that counts the number of hits from docking in each herb and calculates the hit rate of herbs. Herbalog prioritizes herbs according to their hit rates, and top-ranking herb candidates contain a large repertoire of hits. We used Herbalog as a screening tool and identified labdane diterpenoids from Andrographis paniculata as leading candidates of FABP4 inhibitors. CONCLUSION: Herbalog facilitates the discovery of herbs that possess the highest number of inhibitors or activators against target proteins, which reduces the sample preparation time for preliminary validation.

Dietary Omega-3 Fatty Acids Prevented Adipocyte Hypertrophy by Downregulating DGAT-2 and FABP-4 in a Sex-Dependent Fashion.

Obesity is characterized by an increase in fat mass primarily as a result of adipocyte hypertrophy. Diets enriched in omega (n)-3 polyunsaturated fatty acids (PUFA) are suggested to reduce obesity, however, the mechanisms are not well understood. We investigated the effect of n-3 PUFA on adipocyte hypertrophy and the key genes involved in adipocyte hypertrophy. Female C57BL/6 mice were fed semi-purified diets (20 % w/w fat) containing high n-3 PUFA before mating, during pregnancy, and until weaning. Male and female offspring were continued on high n-3 PUFA (10 % w/w), medium n-3 PUFA (4 % w/w), or low n-3 PUFA (2 % w/w) diet for 16 weeks postweaning. Adipocyte area was quantified using microscopy, and gonadal mRNA expression of acyl CoA:diacylglycerol acyltransferase-2 (DGAT-2), fatty acid binding protein-4 (FABP-4) and leptin were measured. The high n-3 PUFA group showed higher levels of total n-3 PUFA in gonadal TAG compared to the medium and low n-3 PUFA groups (P < 0.001). The high n-3 PUFA male group had a lower adipocyte area compared to the medium and low n-3 PUFA group (P < 0.001); however, no difference was observed in females. The high n-3 PUFA male group showed lower mRNA expression of FABP-4, DGAT-2 and leptin compared to the low n-3 PUFA group, with no difference in females. Plasma lipid levels were lower in the high n-3 PUFA group compared to the other groups. Our findings show for the first time that n-3 PUFA prevents adipocyte hypertrophy by downregulating FABP-4, DGAT-2 and leptin; the effects are however sex-specific.

Improved adipose tissue metabolism after 5-year growth hormone replacement therapy in growth hormone deficient adults: The role of zinc-α2-glycoprotein.

Growth hormone (GH) supplementation therapy to adults with GH deficiency has beneficial effects on adipose tissue lipid metabolism, improving thus adipocyte functional morphology and insulin sensitivity. However, molecular nature of these effects remains unclear. We therefore tested the hypothesis that lipid-mobilizing adipokine zinc-α2-glycoprotein is causally linked to GH effects on adipose tissue lipid metabolism. Seventeen patients with severe GH deficiency examined before and after the 5-year GH replacement therapy were compared with age-, gender- and BMI-matched healthy controls. Euglycemic hyperinsulinemic clamp was used to assess whole-body and adipose tissue-specific insulin sensitivity. Glucose tolerance was determined by oGTT, visceral and subcutaneous abdominal adiposity by MRI, adipocyte size morphometrically after collagenase digestion, lipid accumulation and release was studied in differentiated human primary adipocytes in association with GH treatment and zinc-α2-glycoprotein gene silencing. Five-year GH replacement therapy improved glucose tolerance, adipose tissue insulin sensitivity and reduced adipocyte size without affecting adiposity and whole-body insulin sensitivity. Adipose tissue zinc-α2-glycoprotein expression was positively associated with whole-body and adipose tissue insulin sensitivity and negatively with adipocyte size. GH treatment to adipocytes in vitro increased zinc-α2-glycoprotein expression (>50%) and was paralleled by enhanced lipolysis and decreased triglyceride accumulation (>35%). Moreover, GH treatment improved antilipolytic action of insulin in cultured adipocytes. Most importantly, silencing zinc-α2-glycoprotein eliminated all of the GH effects on adipocyte lipid metabolism. Effects of 5-year GH supplementation therapy on adipose tissue lipid metabolism and insulin sensitivity are associated with zinc-α2-glycoprotein. Presence of this adipokine is required for the GH action on adipocyte lipid metabolism in vitro.

Novel fatty acid binding protein 4 (FABP4) inhibitors: virtual screening, synthesis and crystal structure determination.

Fatty acid binding protein 4 (FABP4) is a potential drug target for diabetes and atherosclerosis. For discovering new chemical entities as FABP4 inhibitors, structure-based virtual screening (VS) was performed, bioassay demonstrated that 16 of 251 tested compounds are FABP4 inhibitors, among which compound m1 are more active than endogenous ligand linoleic acid (LA). Based on the structure of m1, new derivatives were designed and prepared, leading to the discovery of two more potent inhibitors, compounds 9 and 10. To further explore the binding mechanisms of these new inhibitors, we determined the X-ray structures of the complexes of FABP4-9 and FABP4-10, which revealed similar binding conformations of the two compounds. Residue Ser53 and Arg126 formed direct hydrogen bonding with the ligands. We also found that 10 could significantly reduce the levels of lipolysis on mouse 3T3-L1 adipocytes. Taken together, in silico, in vitro and crystallographic data provide useful hints for future development of novel inhibitors against FABP4.

Novel insights of dietary polyphenols and obesity.

The prevalence of obesity has steadily increased over the past three decades both in the United States and worldwide. Recent studies have shown the role of dietary polyphenols in the prevention of obesity and obesity-related chronic diseases. Here, we evaluated the impact of commonly consumed polyphenols, including green tea catechins, especially epigallocatechin gallates, resveratrol and curcumin, on obesity and obesity-related inflammation. Cellular studies demonstrated that these dietary polyphenols reduce viability of adipocytes and proliferation of preadipocytes, suppress adipocyte differentiation and triglyceride accumulation, stimulate lipolysis and fatty acid ß-oxidation, and reduce inflammation. Concomitantly, the polyphenols modulate signaling pathways including the adenosine-monophosphate-activated protein kinase, peroxisome proliferator activated receptor γ, CCAAT/enhancer binding protein α, peroxisome proliferator activator receptor gamma activator 1-alpha, sirtuin 1, sterol regulatory element binding protein-1c, uncoupling proteins 1 and 2, and nuclear factor-κB that regulate adipogenesis, antioxidant and anti-inflammatory responses. Animal studies strongly suggest that commonly consumed polyphenols described in this review have a pronounced effect on obesity as shown by lower body weight, fat mass and triglycerides through enhancing energy expenditure and fat utilization, and modulating glucose hemostasis. Limited human studies have been conducted in this area and are inconsistent about the antiobesity impact of dietary polyphenols probably due to the various study designs and lengths, variation among subjects (age, gender, ethnicity), chemical forms of the dietary polyphenols used and confounding factors such as other weight-reducing agents. Future randomized controlled trials are warranted to reconcile the discrepancies between preclinical efficacies and inconclusive clinic outcomes of these polyphenols.

Antiobesity effects of quercetin-rich onion peel extract on the differentiation of 3T3-L1 preadipocytes and the adipogenesis in high fat-fed rats.

The aim of the present study was to examine the effect of quercetin-rich onion peel extract (OPE) on anti-differentiation in 3T3-L1 preadipocytes and the antiobesity in high-fat fed rats. We found that lipid accumulations and TG contents in 3T3-L1 cells were markedly suppressed by OPE. The mRNA levels of activating protein (AP2) were down-regulated and those of carnitine palmitoyl transferase-1 α (CPT-1α) and fatty acid binding protein 4 (FABP4) were up-regulated by 75 and 100 µg/ml OPE. Body weight, retroperitoneal and mesenteric fat weights of SD rats were significantly lower in the 8 week high fat (HF) diet+0.72% OPE group than in the HF group. Peroxisome proliferator-activated receptor (PPAR)γ mRNA levels were down-regulated in the epididymal fat of OPE than those of control and HF, and significant down-regulation of CCAAT/enhancer binding protein (C/EBP)α mRNA levels in OPE was also observed than the control. The mRNA levels of CPT-1α and uncoupling protein-1 (UCP-1) were up-regulated by the OPE, while those of fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC) were down-regulated in HF and OPE groups compared to control group. These results suggest that quercentin-enriched OPE may have antiobesity effects by suppressing preadipocyte differentiation and inhibiting adipogenesis.