Extract of Wax Gourd Peel Prevents High-Fat Diet-Induced Hyperlipidemia in C57BL/6 Mice via the Inhibition of the PPARγ Pathway

Xiaozhi formula attenuates non-alcoholic fatty liver disease by regulating lipid metabolism via activation of AMPK and PPAR pathways

BACKGROUND

Xiaozhi formula (XZF) is a practical Chinese herbal formula for the treatment of non-alcoholic fatty liver disease (NAFLD), which possesses an authorized patent certificate issued by the State Intellectual Property Office of China (ZL202211392355.0). However, the underlying mechanism by which XZF treats NAFLD remains unclear.

PURPOSE

This study aimed to explore the main component of XZF and its mechanism of action in NAFLD treatment.

METHODS

UHPLC-Q-Orbitrap HRMS was used to identify the components of the XZF. A high-fat diet (HFD)-induced NAFLD mouse model was used to demonstrate the effectiveness of XZF. Body weight, liver weight, and white fat weight were recorded to evaluate the therapeutic efficacy of XZF. H&E and Oil Red O staining were applied to observe the extent of hepatic steatosis. Liver damage, lipid metabolism, and glucose metabolism were detected by relevant assay kits. Moreover, the intraperitoneal insulin tolerance test and the intraperitoneal glucose tolerance test were employed to evaluate the efficacy of XZF in insulin homeostasis. Hepatocyte oxidative damage markers were detected to assess the efficacy of XZF in preventing oxidative stress. Label-free proteomics was used to investigate the underlying mechanism of XZF in NAFLD. RT-qPCR was used to calculate the expression levels of lipid metabolism genes. Western blot analysis was applied to detect the hepatic protein expression of AMPK, p-AMPK, PPARɑ, CPT1, and PPARγ.

RESULTS

120 compounds were preliminarily identified from XZF by UHPLC-Q-Orbitrap HRMS. XZF could alleviate HFD-induced obesity, white adipocyte size, lipid accumulation, and hepatic steatosis in mice. Additionally, XZF could normalize glucose levels, improve glucolipid metabolism disorders, and prevent oxidative stress damage induced by HFD. Furthermore, the proteomic analysis showed that the major pathways in fatty acid metabolism and the PPAR signaling pathway were significantly impacted by XZF treatment. The expression levels of several lipolytic and β-oxidation genes were up-regulated, while the expression of fatty acid synthesis genes declined in the HFD + XZF group. Mechanically, XZF treatment enhanced the expression of p-AMPK, PPARɑ, and CPT-1 and suppressed the expression of PPARγ in the livers of NAFLD mice, indicating that XZF could activate the AMPK and PPAR pathways to attenuate NALFD progression.

CONCLUSION

XZF could attenuate NAFLD by moderating lipid metabolism by activating AMPK and PPAR signaling pathways.

Genome-wide identification of bZIP gene family and expression analysis of BhbZIP58 under heat stress in wax gourd

BACKGROUND

The basic leucine zipper (bZIP) transcription factor family is one of the most abundant and evolutionarily conserved gene families in plants. It assumes crucial functions in the life cycle of plants, including pathogen defense, secondary metabolism, stress response, seed maturation, and flower development. Although the genome of wax gourd has been published, little is known about the functions, evolutionary background, and gene expression patterns of the bZIP gene family, which limits its utilization.

RESULTS

A total of 61 bZIP genes (BhbZIPs) were identified from wax gourd (Benincasa hispida) genome and divided into 12 subgroups. Whole-genome duplication (WGD) and dispersed duplication (DSD) were the main driving forces of bZIP gene family expansion in wax gourd, and this family may have undergone intense purifying selection pressure during the evolutionary process. We selected BhbZIP58, only one in the member of subgroup B, to study its expression patterns under different stresses, including heat, salt, drought, cold stress, and ABA treatment. Surprisingly, BhbZIP58 had a dramatic response under heat stress. BhbZIP58 showed the highest expression level in the root compared with leaves, stem, stamen, pistil, and ovary. In addition, BhbZIP58 protein was located in the nucleus and had transcriptional activation activity. Overexpression of BhbZIP58 in Arabidopsis enhanced their heat tolerance.

CONCLUSIONS

In this study, bZIP gene family is systematically bioinformatically in wax gourd for the first time. Particularly, BhbZIP58 may have an important role in heat stress. It will facilitate further research on the bZIP gene family regarding their evolutionary history and biological functions.

Comparative transcriptome provides insights into gene regulation network associated with the resistance to Fusarium wilt in grafted wax gourd Benincasa hispida

Introduction

Wilt is a soil-borne disease caused by Fusarium that has become a serious threat to wax gourd production. Disease-resistant graft wax gourds are an effective treatment for Fusarium wilt. However, there are few reports on the defense mechanism of graft wax gourd against wilt diseases.

Methods

In the present study, disease and growth indices were compared between grafted and original wax gourds after infection with Fusarium. High level of disease resistance was observed in the grafted wax gourd, with a lower disease index and low impacts on growth after infection. RNA-seq was performed to identify the differentially expressed genes (DEGs) between the adjacent treatment time points in the grafted and original wax gourds, respectively. Then a comparative temporal analysis was performed and a total of 1,190 genes were identified to show different gene expression patterns between the two wax gourd groups during Fusarium infection.

Result and discussion

Here, high level of disease resistance was observed in the grafted wax gourd, with a lower disease index and low impacts on growth after infection. The DEG number was higher in grafted group than original group, and the enriched functional categories and pathways of DEGs were largely inconsistent between the two groups. These genes were enriched in multiple pathways, of which the mitogen-activated protein kinase (MAPK) signaling pathway enhanced the early defense response, and cutin, suberin, and wax biosynthesis signaling pathways enhanced surface resistance in grafted wax gourd in comparison to original group. Our study provides insights into the gene regulatory mechanisms underlying the resistance of grafted wax gourds to Fusarium wilt infection, which will facilitate the breeding and production of wilt-resistant rootstocks.

Ethnopharmacology, phytochemistry and pharmacology of Benincasae Exocarpium: A review

Benincasae Exocarpium (BE, Dongguapi in Chinese), as the dried outer pericarp of Benincasa hispida (wax gourd) in Cucurbitaceae family, is one of traditional Chinese medicines with the same origin as medicine and food. Up to now, 43 compounds were isolated from BE, including flavonoids, alkaloids, tannins, phenolic acids, soluble fiber and carbohydrates. Modern pharmacological studies and clinical practice showed that BE has diuretic, hypolipidemic effects, hypoglycemic, antioxidant, antibacterial, and other effects. The folk uses, functional factors, pharmacological activities, patents and clinical applications of BE were reviewed in this paper. In addition, the paper also discussed the current problems for the further studies. The information summarized in this paper provides valuable clues for the comprehensive utilization of medicine and food resources and gives a scientific basis for the development of medicinal plants of BE.

Genome-Wide Identification of the SAUR Gene Family in Wax Gourd (Benincasa hispida) and Functional Characterization of BhSAUR60 during Fruit Development

The wax gourd (Benincasa hispida) is an important vegetable crop whose fruits contain nutrients and metabolites. Small auxin upregulated RNA (SAUR) genes constitute the largest early auxin-responsive gene family and regulate various biological processes in plants, although this gene family has not been studied in the wax gourd. Here, we performed genome-wide identification of the SAUR gene family in wax gourds and analyzed their syntenic and phylogenetic relationships, gene structures, conserved motifs, cis-acting elements, and expression patterns. A total of 68 SAUR (BhSAUR) genes were identified, which were distributed on nine chromosomes with 41 genes in two clusters. More than half of the BhSAUR genes were derived from tandem duplication events. The BhSAUR proteins were classified into seven subfamilies. BhSAUR gene promoters contained cis-acting elements involved in plant hormone and environmental signal responses. Further expression profiles showed that BhSAUR genes displayed different expression patterns. BhSAUR60 was highly expressed in fruits, and overexpression led to longer fruits in Arabidopsis. In addition, the plants with overexpression displayed longer floral organs and wavy stems. In conclusion, our results provide a systematic analysis of the wax gourd SAUR gene family and facilitate the functional study of BhSAUR60 during wax gourd fruit development.

Genetic mapping and genome-wide association study identify BhYAB4 as the candidate gene regulating seed shape in wax gourd (Benincasa hispida)

Wax gourd is an important vegetable crop of the Cucurbitaceae family. According to the shape and structure of the seed coat, the seeds of the wax gourd can be divided into bilateral and unilateral. Bilateral seeds usually germinate quickly and have a high germination rate than unilateral seeds. Thereby, wax gourd varieties with bilateral seeds are more welcomed by seed companies and growers. However, the genetic basis and molecular mechanism regulating seed shape remain unclear in the wax gourd. In this study, the genetic analysis demonstrated that the seed shape of wax gourd was controlled by a single gene, with bilateral dominant to unilateral. Combined with genetic mapping and genome-wide association study, Bhi04G000544 (BhYAB4), encoding a YABBY transcription factor, was identified as the candidate gene for seed shape determination in the wax gourd. A G/A single nucleotide polymorphism variation of BhYAB4 was detected among different germplasm resources, with BhYAB4^G specifically enriched in bilateral seeds and BhYAB4^A in unilateral seeds. The G to A mutation caused intron retention and premature stop codon of BhYAB4. Expression analysis showed that both BhYAB4^G and BhYAB4^A were highly expressed in seeds, while the nuclear localization of BhYAB4^A protein was disturbed compared with that of BhYAB4^G protein. Finally, a derived cleaved amplified polymorphic sequence marker that could efficiently distinguish between bilateral and unilateral seeds was developed, thereby facilitating the molecular marker-assisted breeding of wax gourd cultivars.

Development and Application of InDel Markers Linked to Fruit-Shape and Peel-Colour Genes in Wax Gourd

The wax gourd is commonly grown in many countries because of its high nutritional and economic value. While the genes for the fruit shape and peel colour of wax gourd have been reported, the InDel markers linked to these genes remain undeveloped. In this study, the InDel markers linked to fruit-shape (Bch02G016830) and peel-colour (Bch05G003950) genes were developed from resequenced data. We used 120 inbred lines, 536 isolated populations, and 4 commercial hybrids to evaluate the validity and application value of the InDel markers. The accuracy rates of nine pairs of fruit-shape InDel markers (GX1-GX9) were 84.16–91.66% in 120 inbred lines. The accuracy rates of 27 pairs of peel-colour InDel markers (PS1-PS27) within approximately 3.0 Mb upstream and 3.0 Mb downstream of the peel-colour gene were 100% and those of 6 pairs of peel-colour InDel markers (PS28-PS33) within 3.0–20 Mb upstream and downstream of the peel-colour gene were 55.83–90% in 120 inbred lines. The purity of four commercial hybrids determined using GX1, GX2, PS13, and PS14 was highly consistent with the field results for purity determination. Our results provide important information for genetic linkage map construction, molecular-marker-assisted selective breeding, and purity determination of wax gourd hybrids.

Genome-Wide Identification of YABBY Gene Family in Cucurbitaceae and Expression Analysis in Cucumber (Cucumis sativus L.)

YABBY transcription factors play important roles in plant growth and development. However, little is known about YABBY genes in Cucurbitaceae. Here, we identified 59 YABBY genes from eight cucurbit species, including cucumber (C. sativus L.), melon (C. melon L.), watermelon (C. lanatus), wax gourd (B. hispida), pumpkin (C. maxima), zucchini (C. pepo L.), silver-seed gourd (C. argyrosperma), and bottle gourd (L. siceraria). The 59 YABBY genes were clustered into five subfamilies wherein the gene structures and motifs are conserved, suggesting similar functions within each subfamily. Different YABBY gene numbers in eight cucurbit species indicated that gene loss or duplication events exist in an evolutionary process across Cucurbitaceae. The cis-acting elements analysis implied that the YABBYs may be involved in plant development, and phytohormone, stress, and light responses. Importantly, YABBY genes exhibited organ-specific patterns in expression in cucumber. Furthermore, a gene CsaV3_6G038650 was constitutively expressed at higher levels at different fruit development stages and might play a crucial role in cucumber fruit development. Collectively, our work will provide a better understanding for further function identifications of YABBY genes in Cucurbitaceae.

Isolation of Anti-Diabetic Active Compounds from Benincasae Exocarpium and Development of Simultaneous Analysis by HPLC-PDA

Diabetes is a chronic metabolic disease that is a constant problem. Previous studies have reported that Benincasa cerifera Savi. extracts are effective in treating diabetes and its complications. Benincasae Exocarpium (BE) is a fruit peel of B. cerifera that has been reported to be used for the prevention and treatment of metabolic diseases such as hyperglycemia, obesity, and hyperlipidemia. However, there are not enough studies on the compounds and bioassays to support the efficacy of BE. The inhibitory activity of the BE extracts and fractions against advanced glycation end-products (AGE) formation and α-glucosidase activity was evaluated. These assays are relevant for the treatment of type 2 diabetes and its complications. Based on these results, compounds 1-11 were isolated through bioassay-guided isolation. In addition, we developed a high-performance liquid chromatography (HPLC) method that can simultaneously analyze these 11 compounds. Activity evaluation of the compounds was also conducted, and eight compounds exhibited significant activity. Among these, flavonoid compounds showed strong activity. A quantitative evaluation of eight bioactive compounds (2, 5-11) was conducted. In conclusion, this study demonstrated the potential of BE for prevention and treatment of type 2 diabetes and its complications.

The wax gourd genomes offer insights into the genetic diversity and ancestral cucurbit karyotype

The botanical family Cucurbitaceae includes a variety of fruit crops with global or local economic importance. How their genomes evolve and the genetic basis of diversity remain largely unexplored. In this study, we sequence the genome of the wax gourd (Benincasa hispida), which bears giant fruit up to 80 cm in length and weighing over 20 kg. Comparative analyses of six cucurbit genomes reveal that the wax gourd genome represents the most ancestral karyotype, with the predicted ancestral genome having 15 proto-chromosomes. We also resequence 146 lines of diverse germplasm and build a variation map consisting of 16 million variations. Combining population genetics and linkage mapping, we identify a number of regions/genes potentially selected during domestication and improvement, some of which likely contribute to the large fruit size in wax gourds. Our analyses of these data help to understand genome evolution and function in cucurbits.

Cucurbits fruits have diverse shapes and sizes, but their genomes evolution and genetic basis of diversity are unclear. Here, the authors show that the wax gourd genome has the most ancestral karyotype among cucurbits and identify candidate genes which contribute to large fruit size by comparative and population genomics analyses.

Hypolipidemic effects of total flavonoide extracted from the leaves of Actinidiakolomikta in rats fed a high-fat diet

OBJECTIVES

This study was to investigate the antihyperlipidemic and antioxidant effect of total flavonoid extract from Actinidiakolomikta (TFAK) in hyperlipidemia induced by a high-fat diet.

MATERIALS AND METHODS

Male SD rats were randomly divided into 6 groups: normal group, model (hyperlipidemic diet) group, hyperlipedemic diet supplemented with TFAK (50, 100 and 200 mg/kg) and simvastatin (30 mg/kg) groups. The rats were administrated TFAK by oral for 28 days. Body weight, total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL-c), superoxide dismutase (SOD), catalase(CAT), glutathione peroxidase(GSH-Px) and malondialdehyde (MDA) were measured. The atherogenic index (AI) and coronary risk index (CRI) were calculated. The activity of hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase in hepatic tissue was examined. Histopathologic changes were also checked.

RESULTS

The levels of TC, TG and LDL-c were increased in model group. Compared to the model group, TFAK reduced significantly the body weight, TC, TG, LDL-c, AI, CRI and elevated the level of HDL-c. Moreover, the activity of SOD was elevated significantly, whereas the content of MDA decreased. The activity of HMG-CoA reductase was also decreased. Morphological evaluation found that rats in model group developed a severe steatosis, but the severity of liver steatosis was ameliorated in TFAK treated groups. The possible mechanism may be associated with decrease HMG-CoA reductase activity.

CONCLUSION

Our results suggest that TFAK exerts strong antioxidant and lipid-lowering effects, prevents hepatic fatty deposition and regulates the HMG-CoA reductase.

MDG-1, a Potential Regulator of PPARα and PPARγ, Ameliorates Dyslipidemia in Mice

Hyperlipidemia is a serious epidemic disease caused by lipid metabolism disorder, which is harmful to human health. MDG-1, a β-d-fructan polysaccharide extracted from Ophiopogon japonicus, has been shown to improve abnormal blood lipid levels and alleviate diabetes. However, the underlying mechanism on hyperlipidemia is largely unknown. In this study, male C57BL/6 mice were randomly separated into three groups, respectively: low-fat diet (Con), high-fat diet (HFD), and high-fat diet plus 5‰ MDG-1 (HFD + MDG-1). Body weight was measured and the serum lipid levels were analyzed. Using gene microarray, various core pathways, together with levels of gene expression within hepatocytes, were analyzed. RT-PCR was used to confirm the identity of the differentially expressed genes. MDG-1 could prevent obesity in HFD-induced mice and improve abnormal serum lipids. Besides, MDG-1 could regulate hyperlipidemia symptoms, specifically, and decrease fasting blood glucose, improve glucose tolerance, and ameliorate insulin resistance. According to results from gene microarray, most of the identified pathways were involved in the digestion and absorption of fat, biosynthesis, and catabolism of fatty acids as well as the secretion and biological synthesis of bile acids. Furthermore, MDG-1 may act upon peroxisome proliferator-activated receptors (PPAR) α and γ, activating PPARα whilst inhibiting PPARγ, thus having a potent hypolipidemic effect.

Effects of canagliflozin on weight loss in high-fat diet-induced obese mice

Canagliflozin, an inhibitor of sodium glucose co-transporter (SGLT) 2, has been shown to reduce body weight during the treatment of type 2 diabetes mellitus (T2DM). In this study, we sought to determine the role of canagliflozin in body weight loss and liver injury in obesity. C57BL/6J mice were fed a high-fat diet to simulate diet-induced obesity (DIO). Canagliflozin (15 and 60 mg/kg) was administered to DIO mice for 4 weeks. Orlistat (10 mg/kg) was used as a positive control. The body weight, liver weight, liver morphology, total cholesterol (TC) and triglyceride (TG) levels were examined. Signaling molecules, including diacylgycero1 acyltransferase-2 (DGAT2), peroxisome proliferation receptor alpha-1 (PPARα1), PPARγ1, PPARγ2 mRNA levels and the protein expression of SGLT2 were evaluated. Canagliflozin reduced body weight, especially the high-dose canagliflozin, and resulted in increased body weight loss compared with orlistat. Moreover, canagliflozin reduced the liver weight and the ratio of liver weight to body weight, lowered the serum levels of TC and TG, and ameliorated liver steatosis. During the canagliflozin treatment, SGLT2, DGAT2, PPARγ1 and PPARγ2 were inhibited, and PPARα1 was elevated in the liver tissues. This finding may explain why body weight was reduced and secondary liver injury was ameliorated in response to canagliflozin. Together, the results suggest that canagliflozin may be a potential anti-obesity strategy.

Bardoxolone Methyl Prevents High-Fat Diet-Induced Colon Inflammation in Mice

Obesity induces chronic, low-grade inflammation, which increases the risk of colon cancer. We investigated the preventive effects of Bardoxolone methyl (BARD) on high-fat diet (HFD)-induced inflammation in a mouse colon. Male C57BL/6J mice (n=7) were fed a HFD (HFD group), HFD plus BARD (10 mg/kg) in drinking water (HFD/BARD group), or normal laboratory chow diet (LFD group) for 21 weeks. In HFD mice, BARD reduced colon thickness and decreased colon weight per length. This was associated with an increase in colon crypt depth and the number of goblet cells per crypt. BARD reduced the expression of F4/80 and CD11c but increased CD206 and IL-10, indicating an anti-inflammatory effect. BARD prevented an increase of the intracellular pro-inflammatory biomarkers (NF-қB, p NF-қB, IL-6, TNF-α) and cell proliferation markers (Cox2 and Ki67). BARD prevented fat deposition in the colon wall and prevented microbial population changes. Overall, we report the preventive effects of BARD on colon inflammation in HFD-fed mice through its regulation of macrophages, NF-қB, cytokines, Cox2 and Ki67, fat deposition and microflora.

Supplementation with the extract of schisandrae fructus pulp, seed, or their combination influences the metabolism of lipids and glucose in mice fed with normal and hypercholesterolemic diet

SCHISANDRAE FRUCTUS (SF), WHICH POSSESSES FIVE TASTES

sweet (fruit skin), sour (pulp), bitter/pungent (seed core), and saltiness (all parts), can produce a wide spectrum of biological activities in the body. Here, we investigated the effects of the ethanolic extract of SF pulp, seed, or their combination (namely, EtSF-P, EtSF-S, or EtSF-P/S, resp.; collectively called EtSF) on the metabolism of lipids and glucose in normal diet- (ND-) and hypercholesterolemic diet- (HCLD-) fed mice. Supplementation with EtSF significantly reduced hepatic triglyceride and cholesterol levels by 18-47% in both ND- and HCLD-fed mice. EtSF supplementation reduced serum triglyceride levels (approximately 29%), whereas EtSF-P and EtSF-S/P elevated serum cholesterol (up to 26 and 44%, resp.) in HCLD-fed mice. Treatment with EtSF decreased hepatic glucose levels (by 9-44%) in both ND- and HCLD-fed mice. Supplementation with EtSF-S or EtSF-S/P (at 1 and 3%) increased biliary or fecal TC contents in HCLD-fed mice. However, supplementation with EtSF-S/P at 9% reduced biliary TC levels in HCLD-fed mice. EtSF-P or EtSF-S/P supplementation reduced serum alanine aminotransferase activity in HCLD-fed mice. The findings suggested that supplementation with EtSF lowered lipid and glucose accumulation in the liver and increased fecal cholesterol contents in mice. Dietary supplementation with EtSF-P or EtSF-S/P attenuated liver damage in HCLD-fed mice.