High-fat Diet Mice Research Articles

Empagliflozin alleviates neuroinflammation by inhibiting astrocyte activation in the brain and regulating gut microbiota of high-fat diet mice

A high-fat diet can modify the composition of gut microbiota, resulting in dysbiosis. Changes in gut microbiota composition can lead to increased permeability of the gut barrier, allowing bacterial products like lipopolysaccharides (LPS) to enter circulation. This process can initiate systemic inflammation and contribute to neuroinflammation. Empagliflozin (EF), an SGLT2 inhibitor-type hypoglycemic drug, has been reported to treat neuroinflammation. However, there is a lack of evidence showing that EF regulates the gut microbiota axis to control neuroinflammation in HFD models. In this study, we explored whether EF could improve neuroinflammation caused by an HFD via regulation of the gut microbiota and the mechanism underlying this phenomenon. Our data revealed that EF alleviates pathological brain injury, reduces the reactive proliferation of astrocytes, and increases the expression of synaptophysin. In addition, the levels of inflammatory factors in hippocampal tissue were significantly decreased after EF intervention. Subsequently, the results of 16S rRNA gene sequencing showed that EF could change the microbial community structure of mice, indicating that the abundance of Lactococcus, Ligilactobacillus and other microbial populations decreased dramatically. Therefore, EF alleviates neuroinflammation by inhibiting gut microbiota-mediated astrocyte activation in the brains of high-fat diet-fed mice. Our study focused on the gut-brain axis, and broader research on neuroinflammation can provide a more holistic understanding of the mechanisms driving neurodegenerative diseases and inform the development of effective strategies to mitigate their impact on brain health. The results provide strong evidence supporting the larger clinical application of EF.

#1320 Differential microRNA expression profile in obesity-induced kidney disease driven by high-fat diet in mice

Abstract Background and Aims Obesity is one of the main causes of chronic kidney disease; however, the precise molecular mechanisms leading to the onset of kidney dysfunction in obesity-induced kidney disease (OIKD) remain unclear. MicroRNAs (miRNAs) have been implicated in the development and progression of obesity, and several candidates have been identified as critical regulators of adipogenesis and lipid metabolism, while their dysregulation contribute to obesity-related metabolic abnormalities. The aim of the present study was to decipher the kidney microRNA (miRNA) expression profile in a mouse model of obesity-induced kidney disease characterized by systemic metabolic disturbances and kidney injury that closely resemble those observed in human disease. Method Male C57BL/6J mice were randomly divided and placed either a standard diet (STD) or a high fat diet (HFD) for 10 weeks. Serum triglycerides and total, HDL and LDL cholesterol were determined by standard clinical methods. In the kidney sections, histopathological assessments were done by using PAS and Oil-Red-O staining's. Expression of renal MCP1, TNFα, α-SMA, Fibronectin, miR-146a, miR-551b and miR-5099 was assessed by real time PCR. In order to elucidate the role of differentially expressed miRNAs, a search for target genes was done using an online computational resource DIANA-miRPath v4.0. Results High fat diet (HFD)-induced obesity led to evident structural alterations in tubular and glomerular regions of the kidney, increased renal expression of adiposity-related proinflammatory and profibrotic genes, as well as an elevated renal expression of genes involved in cellular lipid metabolism. The miRNA sequencing analysis identified a set of 9 miRNAs differentially expressed in the kidney upon HFD feeding, with miR-5099, miR-551b-3p, miR-223-3p, miR-146a-3p and miR-21a-3p showing most significant differential expression between standard diet (STD) and HFD mice. Consistently, Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment analyses revealed that 3 validated miRNAs (miR-5099, miR-551b-3p and miR-146a-3p) modulated target genes involved in metabolic and adipocytokine pathways, fatty acid and lipid metabolism, inflammatory, senescence and profibrotic pathways. Conclusion Our results propose that differentially expressed miRNAs play pivotal roles in the intricated pathophysiology of obesity-associated kidney disease and could potentially create novel treatment strategies to counteract the deleterious effects of obesity on kidney function.

#1895 Elucidating Asprosin's role as an intracellular metabolism regulator in diabetes and obesity-induced renal damage

Abstract Background and Aims Asprosin, an adipokine with a multifaceted function that encompasses inducing insulin resistance, promoting inflammation, and stimulating appetite, is the focus of our investigation. We seek to establish its pivotal role as a mediator in regulating cellular energy metabolism, particularly in the context of renal damage induced by diabetes and obesity. Method We conducted experiments using type 2 diabetic db/db mice and obesity-induced high-fat diet mice. These animal models were categorized into two groups: one received Asprosin neutralizing antibodies (250 μg/mouse/21 days), targeting the 28-amino acid peptide located proximal to Asprosin's C-terminus (KKKELNQLEDRYDKDYLSGELGDNLKMK), while the other received an AMPK activator (Metformin) associated with the regulation of Asprosin receptors (OLFR734/G proteins-cAMP-PKA). Additionally, we cultured renal constituent cells (mesangial cells, glomerular endothelial cells) in high glucose and palmitic acid conditions and silencing Asprosin expression using siRNA. We assessed the levels of Asprosin, AMPK, and their respective downstream signaling pathways. Results Asprosin was found to be overexpressed in the serum and kidney tissues of both db/db mice and high-fat diet mice, as well as in renal constituent cells cultured under high glucose and palmitic acid conditions. Interfering with Asprosin led to reduced body and liver weight in mice, improved glucose tolerance, and mitigated renal injury in vivo. Asprosin knockdown ameliorated lipid accumulation and inflammatory infiltration, both in vitro and in vivo. Moreover, Asprosin absence activated the AMPK/Sirts/mTOR signaling pathway, while the AMPK activator Metformin reversed the effects of Asprosin on lipid accumulation and inflammatory response, confirming Asprosin's direct role in intracellular lipid metabolism. Conclusion The mechanism of intracellular energy metabolism regulation mediated by Asprosin presents promising potential for targeted organ therapy in the development and prevention of diabetic kidney disease. Inhibiting Asprosin suppressed lipid accumulation and inflammation in diabetic kidney disease through the activation of AMPK-associated signaling pathway.

Oleuropein, a Component of Extra Virgin Olive Oil, Improves Liver Steatosis and Lobular Inflammation by Lipopolysaccharides-TLR4 Axis Downregulation.

Gut-dysbiosis-induced lipopolysaccharides (LPS) translocation into systemic circulation has been suggested to be implicated in nonalcoholic fatty liver disease (NAFLD) pathogenesis. This study aimed to assess if oleuropein (OLE), a component of extra virgin olive oil, lowers high-fat-diet (HFD)-induced endotoxemia and, eventually, liver steatosis. An immunohistochemistry analysis of the intestine and liver was performed in (i) control mice (CTR; n = 15), (ii) high-fat-diet fed (HFD) mice (HFD; n = 16), and (iii) HFD mice treated with 6 µg/day of OLE for 30 days (HFD + OLE, n = 13). The HFD mice developed significant liver steatosis compared to the controls, an effect that was significantly reduced in the HFD + OLE-treated mice. The amount of hepatocyte LPS localization and the number of TLR4+ macrophages were higher in the HFD mice in the than controls and were lowered in the HFD + OLE-treated mice. The number of CD42b+ platelets was increased in the liver sinusoids of the HFD mice compared to the controls and decreased in the HFD + OLE-treated mice. Compared to the controls, the HFD-treated mice showed a high percentage of intestine PAS+ goblet cells, an increased length of intestinal crypts, LPS localization and TLR4+ expression, and occludin downregulation, an effect counteracted in the HFD + OLE-treated mice. The HFD-fed animals displayed increased systemic levels of LPS and zonulin, but they were reduced in the HFD + OLE-treated animals. It can be seen that OLE administration improves liver steatosis and inflammation in association with decreased LPS translocation into the systemic circulation, hepatocyte localization of LPS and TLR4 downregulation in HFD-induced mouse model of NAFLD.

Proanthocyanidins isolated from lotus seed skin mitigate glycolipid metabolism disorder through the p38/Nrf2/NF-κB signaling pathway.

Lotus seed skin extract is rich in flavonoids, making it a promising candidate for developing health products. In a previous study, we found that proanthocyanidins from lotus seed skin, particularly proanthocyanidin B1 (PB1), can indirectly activate the Nrf2 signaling pathway, exerting an antioxidant effect. In this study, we isolate proanthocyanidins from lotus seed skin (PLS) using ethanol extraction and RP-HPLC identification, and investigate its effects on glycolipid metabolism both in vivo and in vitro. Our results demonstrate that PLS reduces body weight in high-fat diet (HFD) mice by decreasing feed efficiency. PLS also normalizes serum glucose, insulin secretion, glycosylated hemoglobin (HbA1c), and intraperitoneal glucose tolerance (IPGTT). Furthermore, PLS significantly improves blood lipid parameters and inhibits the expressions of six proinflammatory factors, including IL-1α, IL-1β, IL-3, IL-6, IFN-γ and TNF-α in HFD mice. Additionally, analysis of fresh liver tissues reveals that PLS and PB1 induce the expressions of antioxidant proteins such as HO-1 and NQO1 by activating the p38-Nrf2 signaling pathway and inhibiting the NF-κB signaling pathway. In conclusion, proanthocyanidins from lotus seed skin regulate glycolipid metabolism disorders by targeting the p38/Nrf2/NF-κB signaling pathway. Our study offers a new approach for the high-value comprehensive utilization of lotus seed skin by-products and precise dietary intervention for metabolic syndrome.

A graminan type fructan from Achyranthes bidentata prevents the kidney injury in diabetic mice by regulating gut microbiota

Diabetic kidney disease (DKD) is the main cause of end-stage renal disease, and few therapeutic options are available. The root of Achyranthis bidentatae (AB) is commonly used for DKD treatment in Traditional Chinese medicine. However, its mechanisms are still unclear. Here, a graminan type fructan ABPW1 with molecular weight of 3998 Da was purified from AB. It was composed of β-1,2-linked Fruf, β-2,6-linked-Fruf and β-1,2,6-linked-Fruf backbone, and terminated with T-Glcp and 2-Fruf residues. ABPW1 protected against kidney injuries and intestinal barrier disruption in Streptozotocin (STZ)/High fat diet (HFD) mice. It could modulate gut microbiota composition, evidenced by a rise in the abundance of Bacteroide and decreases of Rikenella, Alistipes, Laedolimicola and Faecalibaculum. ABPW1 intervention promoted short chain fatty acids (SCFAs) production in STZ/HFD mice, especially propionate and isobutyric acid. Antibiotic treatment further demonstrated the key role of gut microbiota in the renal protective action of ABPW1. In addition, in vitro simulated digestion and fermentation together with in vivo fluorescent labeling studies demonstrated ABPW1 was indigestible in upper digestive tract but could reach the colon and be degraded into SCFAs by gut microbiota there. Overall, these data suggested ABPW1 has the potential application on DKD prevention.

A network pharmacology-based method to explore the therapeutic effect of honokiol on diabetes with comorbid depression in mice

The effective treatment of diabetes with comorbid depression is a big challenge so far. Honokiol, a bioactive compound from the dietary supplement Magnolia officinalis extract, possesses multiple health benefits. The present study aims to propose a network pharmacology-based method to elucidate potential targets of honokiol in treating diabetes with comorbid depression and related mechanisms. The antidepressant-like efficacy of honokiol was evaluated in high-fat diet (HFD) induced diabetic mice using animal behavior testing, immuno-staining and western blotting assay. Through network pharmacology analysis, retinoid X receptor alpha (RXRα) and vitamin D receptor (VDR) were identified as potential targets related to diabetes and depression. The stable binding conformation between honokiol and RXR/VDR was determined by molecular docking simulation. Moreover, hononkiol effectively alleviated depression-like behaviors in HFD diabetic mice, presented anti-diabetic and anti-neuroinflammatory functions, and protected the hippocampal neuroplasticity. Importantly, honokiol could activate RXR/VDR heterodimer in vivo. The beneficial effects of honokiol on HFD mice were significantly suppressed by UVI3003 (a RXR antagonist), while enhanced by calcitriol (a VDR agonist). Additionally, the disruption of autophagy in the hippocampus of HFD mice was ameliorated by honokiol, which was attenuated by UVI3003 but strengthened by calcitriol. Taken together, the data provide new evidence that honokiol exerts the antidepressant-like effect in HFD diabetic mice via activating RXR/VDR heterodimer to restore the balance of autophagy. Our findings indicate that the RXR/VDR-mediated signaling might be a potential target for treating diabetes with comorbid depression.

Sulfonylureas exert antidiabetic action on adipocytes by inhibition of PPARγ serine 273 phosphorylation

ObjectiveSulfonylureas (SUs) are still among the mostly prescribed antidiabetic drugs with an established mode of action: release of insulin from pancreatic β-cells. In addition, effects of SUs on adipocytes by activation of the nuclear receptor peroxisome proliferator-activated receptor γ (PPARγ) have been described, which might explain their insulin-sensitizing potential observed in patients. However, there is a discrepancy between the impact of SUs on antidiabetic action and their rather moderate in vitro effect on PPARγ transcriptional activity. Recent studies have shown that some PPARγ ligands can improve insulin sensitivity by blocking PPARγ Ser-273 phosphorylation without having full agonist activity. It is unknown if SUs elicit their antidiabetic effects on adipocytes by inhibition of PPARγ phosphorylation. Here, we investigated if binding of SUs to PPARγ can interfere with PPARγ Ser-273 phosphorylation and determined their antidiabetic actions in vitro in primary human white adipocytes and in vivo in high-fat diet (HFD) obese mice. MethodsPrimary human white preadipocytes were differentiated in the presence of glibenclamide, glimepiride and PPARγ ligands rosiglitazone and SR1664 to compare PPARγ Ser-273 phosphorylation, glucose uptake and adipokine expression. Transcriptional activity at PPARγ was determined by luciferase assays, quantification of PPARγ Ser-273 phosphorylation was determined by Western blotting and CDK5 kinase assays. In silico modelling was performed to gain insight into the binding characteristics of SUs to PPARγ. HFD mice were administered SUs and rosiglitazone for 6 days. PPARγ Ser-273 phosphorylation in white adipose tissue (WAT), body composition, glucose tolerance, adipocyte morphology and expression levels of genes involved in PPARγ activity in WAT and brown adipose tissue (BAT) were evaluated. ResultsSUs inhibit phosphorylation of PPARγ at Ser-273 in primary human white adipocytes and exhibit a positive antidiabetic expression profile, which is characterized by up regulation of insulin-sensitizing and down regulation of insulin resistance-inducing adipokines. We demonstrate that SUs directly bind to PPARγ by in silico modelling and inhibit phosphorylation in kinase assays to a similar extend as rosiglitazone and SR1664. In HFD mice SUs reduce PPARγ phosphorylation in WAT and have comparable effects on gene expression to rosiglitazone. In BAT SUs increase UCP1 expression and reduce lipid droplets sizes. ConclusionsOur findings indicate that a part of SUs extra-pancreatic effects on adipocytes in vitro and in vivo is probably mediated via their interference with PPARγ phosphorylation rather than via classical agonistic activity at clinical concentrations.

Impact of Plant-Based Dietary Fibers on Metabolic Homeostasis in High-Fat Diet Mice via Alterations in the Gut Microbiota and Metabolites

BackgroundThe gut microbiota contributes to metabolic disease, and diet shapes the gut microbiota, emphasizing the need to better understand how diet impacts metabolic disease via gut microbiota alterations. Fiber intake is linked with improvements in metabolic homeostasis in rodents and humans, which is associated with changes in the gut microbiota. However, dietary fiber is extremely heterogeneous, and it is imperative to comprehensively analyze the impact of various plant-based fibers on metabolic homeostasis in an identical setting and compare the impact of alterations in the gut microbiota and bacterially derived metabolites from different fiber sources. ObjectivesThe objective of this study was to analyze the impact of different plant-based fibers (pectin, β-glucan, wheat dextrin, resistant starch, and cellulose as a control) on metabolic homeostasis through alterations in the gut microbiota and its metabolites in high-fat diet (HFD)-fed mice. MethodsHFD-fed mice were supplemented with 5 different fiber types (pectin, β-glucan, wheat dextrin, resistant starch, or cellulose as a control) at 10% (wt/wt) for 18 wk (n = 12/group), measuring body weight, adiposity, indirect calorimetry, glucose tolerance, and the gut microbiota and metabolites. ResultsOnly β-glucan supplementation during HFD-feeding decreased adiposity and body weight gain and improved glucose tolerance compared with HFD-cellulose, whereas all other fibers had no effect. This was associated with increased energy expenditure and locomotor activity in mice compared with HFD-cellulose. All fibers supplemented into an HFD uniquely shifted the intestinal microbiota and cecal short-chain fatty acids; however, only β-glucan supplementation increased cecal butyrate concentrations. Lastly, all fibers altered the small-intestinal microbiota and portal bile acid composition. ConclusionsThese findings demonstrate that β-glucan consumption is a promising dietary strategy for metabolic disease, possibly via increased energy expenditure through alterations in the gut microbiota and bacterial metabolites in mice.

Phoenixin knockout mice show no impairment in fertility or differences in metabolic response to a high-fat diet, but exhibit behavioral differences in an open field test.

Phoenixin (PNX) is a conserved secreted peptide that was identified 10 years ago with numerous studies published on its pleiotropic functions. PNX is associated with estrous cycle length, protection from a high-fat diet, and reduction of anxiety behavior. However, no study had yet evaluated the impact of deleting PNX in the whole animal. We sought to evaluate a mouse model lacking the PNX parent gene, small integral membrane protein 20 (Smim20), and the resulting effect on reproduction, energy homeostasis, and anxiety. We found that the Smim20 knockout mice had normal fertility and estrous cycle lengths. Consistent with normal fertility, the hypothalamii of the knockout mice showed no changes in the levels of reproduction-related genes, but the male mice had some changes in energy homeostasis-related genes, such as melanocortin receptor 4 (Mc4r). When placed on a high-fat diet, the wildtype and knockout mice responded similarly, but the male heterozygous mice gained slightly less weight. When placed in an open field test box, the female knockout mice traveled less distance in the outer zone, indicating alterations in anxiety or locomotor behavior. In summary, the homozygous knockout of PNX did not alter fertility and modestly alters a few neuroendocrine genes in response to a high-fat diet, especially in the female mice. However, it altered the behavior of mice in an open field test. PNX therefore may not be crucial for reproductive function or weight, however, we cannot rule out possible compensatory mechanisms in the knockout model. Understanding the role of PNX in physiology may ultimately lead to an enhanced understanding of neuroendocrine mechanisms involving this enigmatic peptide.

Acod1/itaconate activates Nrf2 in pulmonary microvascular endothelial cells to protect against the obesity-induced pulmonary microvascular endotheliopathy

BackgroundObesity is the main risk factor leading to the development of various respiratory diseases, such as asthma and pulmonary hypertension. Pulmonary microvascular endothelial cells (PMVECs) play a significant role in the development of lung diseases. Aconitate decarboxylase 1 (Acod1) mediates the production of itaconate, and Acod1/itaconate axis has been reported to play a protective role in multiple diseases. However, the roles of Acod1/itaconate axis in the PMVECs of obese mice are still unclear.MethodsmRNA-seq was performed to identify the differentially expressed genes (DEGs) between high-fat diet (HFD)-induced PMVECs and chow-fed PMVECs in mice (|log2 fold change| ≥ 1, p ≤ 0.05). Free fatty acid (FFA) was used to induce cell injury, inflammation and mitochondrial oxidative stress in mouse PMVECs after transfection with the Acod1 overexpressed plasmid or 4-Octyl Itaconate (4-OI) administration. In addition, we investigated whether the nuclear factor erythroid 2-like 2 (Nrf2) pathway was involved in the effects of Acod1/itaconate in FFA-induced PMVECs.ResultsDown-regulated Acod1 was identified in HFD mouse PMVECs by mRNA-seq. Acod1 expression was also reduced in FFA-treated PMVECs. Acod1 overexpression inhibited cell injury, inflammation and mitochondrial oxidative stress induced by FFA in mouse PMVECs. 4-OI administration showed the consistent results in FFA-treated mouse PMVECs. Moreover, silencing Nrf2 reversed the effects of Acod1 overexpression and 4-OI administration in FFA-treated PMVECs, indicating that Nrf2 activation was required for the protective effects of Acod1/itaconate.ConclusionOur results demonstrated that Acod1/Itaconate axis might protect mouse PMVECs from FFA-induced injury, inflammation and mitochondrial oxidative stress via activating Nrf2 pathway. It was meaningful for the treatment of obesity-caused pulmonary microvascular endotheliopathy.

Tamoxifen upregulates the peroxisomal β-oxidation enzyme Enoyl CoA hydratase and 3-hydroxyacyl CoA hydratase ameliorating hepatic lipid accumulation in mice

Tamoxifen is an estrogen receptor modulator that has been reported to alleviate hepatic lipid accumulation in mice, but the mechanism is still unclear. Peroxisome fatty acid β-oxidation is the main metabolic pathway for the overload of long-chain fatty acids. As long-chain fatty acids are a cause of hepatic lipid accumulation, the activation of peroxisome fatty acid β-oxidation might be a novel therapeutic strategy for metabolic associated fatty liver disease. In this study, we investigated the mechanism of tamoxifen against hepatic lipid accumulation based on the activation of peroxisome fatty acid β-oxidation. Tamoxifen reduced liver long-chain fatty acids and relieved hepatic lipid accumulation in high fat diet mice without sex difference. In vitro, tamoxifen protected primary hepatocytes against palmitic acid-induced lipotoxicity. Mechanistically, the RNA-sequence of hepatocytes isolated from the liver revealed that peroxisome fatty acid β-oxidation was activated by tamoxifen. Protein and mRNA expression of enoyl CoA hydratase and 3-hydroxyacyl CoA hydratase were significantly increased in vivo and in vitro. Small interfering RNA enoyl CoA hydratase and 3-hydroxyacyl CoA hydratase in primary hepatocytes abolished the therapeutic effects of tamoxifen in lipid accumulation. In conclusion, our results indicated that tamoxifen could relieve hepatic lipid accumulation in high fat diet mice based on the activation of enoyl CoA hydratase and 3-hydroxyacyl CoA hydratase-mediated peroxisome fatty acids β-oxidation.

Identifying the Crucial Biomarker of MASH-Related HCC.

This study aimed to explore the key oncogenic factor of metabolicassociated steatohepatitis (MASH) to hepatocellular carcinoma (HCC). We utilized four differential GEO datasets (GSE164760, GSE139602, GSE197112, and GSE49541) to identify the key oncogenic factor for MASH-related HCC. The differential genes were analyzed using the GEO2R algorithm online. The GEPIA online website was used to explore the expression of selected four genes (SPP1, GNMT, CLDN11, and THBS2). The genetic alterations in genes were estimated by the cBioPortal website. The Kaplan-Meier Plotter online database was applied to explore the prognostic value of SPP1. Univariate and multivariate Cox analyses were carried out to further confirm the prognostic value of SPP1. The GO and KEGG enrichment analysis exported associated pathways with SPP1 expression. The positively or negatively related immune cells and immune checkpoint expressions were identified through Pearson correlation analysis. The lipogenesis-associated proteins were detected using western blotting and fluorescence. The high-fat diet (HFD) mouse model was constructed, and liver samples were collected. SPP1, GNMT, CLDN11, and THBS2 were determined in the transformation process of MASH to liver fibrosis. SPP1 and GNMT were upregulated in the HCC tumor tissue. SPP1, in particular, had the potential to be the prognostic factor through Cox analysis. Remarkably, SPP1 was highly expressed in HCC compared to normal tissues in three independent datasets (GSE121248, GSE14520, and GSE45267). SPP1 is mainly involved in the amplification and deep deletion mutations. SPP1 was found to be strongly correlated with ANXA2 expression, and ANXA2 was also highly expressed in HCC with significant prognostic performance. Moreover, SPP1 was found to participate in the carcinogenic mechanism and correlate with immune cells and immune checkpoint expression. SPP1 knockdown suppressed the SREBP1 and FASN expressions and increased the SIRT1 expression in vitro. Moreover, the HFD model validated the upregulation of SPP1 in the fatty liver in vivo. SPP1 may be the key oncogenic factor for the transformation of MASH to HCC, and it could be a potential immunotherapeutic target in HCC.

Skeletal muscle cystathionine γ-lyase deficiency promotes obesity and insulin resistance and results in hyperglycemia and skeletal muscle injury upon HFD in mice

ABSTRACT Objectives The objective of this study was to investigate whether skeletal muscle cystathionine γ-lyase (CTH) contributes to high-fat diet (HFD)-induced metabolic disorders using skeletal muscle Cth knockout (CthΔskm ) mice. Methods The Cth Δskm mice and littermate Cth-floxed (Cthf/f ) mice were fed with either HFD or chow diet for 13 weeks. Metabolomics and transcriptome analysis were used to assess the impact of CTH deficiency in skeletal muscle. Results Metabolomics coupled with transcriptome showed that CthΔskm mice displayed impaired energy metabolism and some signaling pathways linked to insulin resistance (IR) in skeletal muscle although the mice had normal insulin sensitivity. HFD led to reduced CTH expression and impaired energy metabolism in skeletal muscle in Cthf/f mice. CTH deficiency and HFD had some common pathways enriched in the aspects of amino acid metabolism, carbon metabolism, and fatty acid metabolism. CthΔskm +HFD mice exhibited increased body weight gain, fasting blood glucose, plasma insulin, and IR, and reduced glucose transporter 4 and CD36 expression in skeletal muscle compared to Cthf/f +HFD mice. Impaired mitochondria and irregular arrangement in myofilament occurred in CthΔskm +HFD mice. Omics analysis showed differential pathways enriched between CthΔskm mice and Cthf/f mice upon HFD. More severity in impaired energy metabolism, reduced AMPK signaling, and increased oxidative stress and ferroptosis occurred in CthΔskm +HFD mice compared to Cthf/f +HFD mice. Discussion Our results indicate that skeletal muscle CTH expression dysregulation contributes to metabolism disorders upon HFD.

MiR-449a disturbs atherosclerotic plaque stability in streptozotocin and high-fat diet-induced diabetic mice by targeting CEACAM1

BackgroundEmerging evidence indicates carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) is involved in the development of atherosclerosis (AS). However, the roles and functions of CEACAM1 in AS remain unknown. Therefore, this study aims to investigate the roles and molecular functions of CEACAM1 in AS.MethodsWe constructed a diabetes mellitus (DM) + high-fat diet (HFD) mouse model based on the streptozotocin (STZ)-induced apolipoprotein E-knockdown (ApopE−/−) mouse to investigate the roles and regulatory mechanism of miR-449a/CEACAM1 axis. The mRNA expression and protein levels in this study were examined using quantity PCR, western blot, immunofluorescence (IF), enzyme-linked immunosorbent assay (ELISA), and immunohistochemistry (IHC), respectively. And the lipid deposition and collagen content were detected using Oil Red O and Sirius Red staining. Cell apoptosis, migration, invasion, and tuber formation were detected by Annexin-V FITC/PI, wound healing, transwell, and tuber formation assays, respectively. The relationship between miR-449a and CEACAM1 was determined by a dual-luciferase reporter gene assay.ResultsmiR-449a and MMP-9 were upregulated, and CEACAM1 was downregulated in the DM + HFD MOUSE model. Upregulation of CEACAM1 promoted atherosclerotic plaque stability and inhibited inflammation in the DM + HFD mouse model. And miR-449a directly targeted CEACAM1. Besides, miR-449a interacted with CEACAM1 to regulate atherosclerotic plaque stability and inflammation in DM-associated AS mice. In vitro, the rescue experiments showed miR-449a interacted with CEACAM1 to affect apoptosis, migration, invasion, and tuber formation ability in high glucose (HG)-induced HUVECs.ConclusionThese results demonstrated that miR-449a promoted plaque instability and inflammation in DM and HFD-induced mice by targeting CEACAM1.

Network pharmacology combined with molecular docking and molecular dynamic simulation to reveal the potential mechanism of lentinan ameliorating hyperlipidemia

Hyperlipidemia is closely related to multiple diseases and is characterized by abnormal serum lipid profiles. The biological function of lentinan in mice and rats was studied, but the mechanism of its lipid-lowering effect was not completely clear. In this study, network pharmacological analysis, molecular docking, and molecular dynamics simulation were used to explore the potential mechanism of its lipid-lowering effect and high-fat diet (HFD) mice was used to confirm the predicted mechanism. Our results indicated that lentinan could ameliorate hyperlipidemia by regulating peroxisome proliferator-activated receptors (PPARs), sterol response element-binding protein-1 (SREBP1), and nuclear factor kappa-B (NF-κB) in the hepatic tissues of mices. Further animal experiment showed that lentinan could regulate the mRNA expressions of lipid metabolism-related genes, such as PPARα, PPARδ, PPARγ, cluster of differentiation 36 (CD36) and SREBP-1c. Moreover, lentinan supplementation could reduce the expressions of inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and inducible nitric oxide sythase (iNOS). In cell model, lentinan also could inhibit oleic acid-induced lipid droplet formation and the expressions of lipid metabolism-related genes and reduced inflammatory factor expressions in HepG2 cells, which further approved the results of animal experiment. Taken together, our results suggest that lentinan can ameliorate hyperlipidemia via regulating lipid metabolism-related gene expressions and reduce obesity-induced inflammatory response.

Alleviation of hepatic insulin resistance and steatosis with NMN via improving endoplasmic reticulum–Mitochondria miscommunication in the liver of HFD mice

The interaction between endoplasmic reticulum (ER) and mitochondria has been shown to play a key role in hepatic steatosis during chronic obesity. β-nicotinamide mononucleotide (NMN) has been reported to regulate obesity, however, its molecular mechanism at the subcellular level remains unclear. Here, NMN improved liver steatosis and insulin resistance in chronic high-fat diet (HFD) mice. RNA-seq showed that compared with the liver of HFD mice, NMN intervention enhanced fat digestion and absorption and stimulated the cholesterol metabolism signaling pathways, while impaired insulin resistance and the fatty acid biosynthesis signaling pathways. Mechanistically, NMN ameliorated mitochondrial dysfunction and ER oxidative stress in the liver of HFD mice by increasing hepatic nicotinamide adenine dinucleotide (NAD+) (P < 0.01) levels. This effect increased the contact sites (mitochondria-associated membranes [MAMs]) between ER and mitochondria, thereby promoting intracellular ATP (P < 0.05) production and mitigating lipid metabolic disturbances in the liver of HFD mice. Taken together, this study provided a theoretical basis for restoring metabolic dynamic equilibrium in the liver of HFD mice by increasing MAMs via the nutritional strategy of NMN supplementation.

Enlarged perivascular spaces in alcohol-related brain damage induced by dyslipidemia

Perivascular spaces (PVSs) as the anatomical basis of the glymphatic system, are increasingly recognized as potential imaging biomarkers of neurological conditions. However, it is not clear whether enlarged PVSs are associated with alcohol-related brain damage (ARBD). We aimed to investigate the effect of long-term alcohol exposure on dyslipidemia and the glymphatic system in ARBD. We found that patients with ARBD exhibited significantly enlargement of PVSs in the frontal cortex and basal ganglia, as well as a notable increased levels of total cholesterol (TC) and triglycerides (TG). The anatomical changes of the glymphatic drainage system mentioned above were positively associated with TC and TG. To further explore whether enlarged PVSs affects the function of the glymphatic system in ARBD, we constructed long alcohol exposure and high fat diet mice models. The mouse model of long alcohol exposure exhibited increased levels of TC and TG, enlarged PVSs, the loss of aquaporin-4 polarity caused by reactive astrocytes and impaired glymphatic drainage function which ultimately caused cognitive deficits, in a similar way as high fat diet leading to impairment in glymphatic drainage. Our study highlights the contribution of dyslipidemia due to long-term alcohol abuse in the impairment of the glymphatic drainage system.

Huangqin-Huanglian Decoction Protects Liver against Non-alcoholic Fatty Liver Disease in High Fat-diet Mice.

Traditional Chinese medicine (TCM) has the advantage of low toxicity of natural ingredients, multiple targets and effects, and low medication costs. It has unique advantages for metabolic and chronic diseases. Huangqin-Huanglian decoction (HQHLD) is composed of Scutellariae Radix, Coptidis Rhizoma, Rehmanniae Radix, and Gentianae Radix Et Rhozima; it has great potential for the treatment of NAFLD with the modern pharmacological research and TCM theory, but there is still a relative lack of research on the potential targets and pharmacological effects of HQHLD. In this work, we have used network pharmacology to predict the targets and signaling pathways of HQHLD, and validated NAFLD-related targets using the HFD model in order to explore more therapeutic drugs and methods for NAFLD. We collected the HQHLD ingredients and NAFLD targets through TCMSP, ETCM, DisGeNET, HGMD, MalaCards, OMIM, and TTD, built ingredients-target networks by Cytoscape, and screened key ingredients in HQHLD. DAVID and Metascape databases were used for GO functional enrichment analysis and KEGG pathway enrichment analysis, respectively. Molecular docking of the key ingredients and key targets was performed by AutoDock. We verified the effect of HQHLD on high-fat diet (HFD) mice by measuring the weight, liver weight index, and the level of TG, TC, LDL-C, and HDLC. HE staining and oil-red staining were performed to detect the damage and fat accumulation in the liver. The changes in INSR, PPAR-α, PPAR-γ, TNF-α, and caspase3 were experimented with WB. With the network pharmacology analysis, we found quercetin, baicalein, sitosterol, wogonin, oroxylin-A, glycyrrhizin, hydroberberine, berberine, sesamin, and carotene to be the main ingredients in HQHLD. According to KEGG pathway analysis, INSR, AKT, JNK1, PPAR-α, PPAR-γ, and the other 16 targets are the main targets of HQHLD in the treatment of NAFLD. We took HFD mice as the in vivo model of NAFLD. Our results showed that HQHLD could reduce liver weight, and TG and LDL-C levels, and increase HDL-C level in serum. By HE and oil red staining, we found that HQHLD could protect the morphology of hepatocytes and reduce fat in the liver. We also found HQHLD to protect the liver by increasing the expression of INSR and PPAR-α, and reducing the expression of PPAR-γ, TNF-α, and caspase3 in the liver. In conclusion, our study has firstly studied the main ingredients and key targets of HQHDL in treating NAFLD by network pharmacology analysis, and preliminarily confirmed that HQHLD could alleviate NAFLD in a multi-target way by lowering fatty acids, and decreasing insulin resistance, inflammation, and apoptosis in the liver.

Chronic exposure to incretin metabolites GLP-1(9−36) and GIP(3−42) affect islet morphology and beta cell health in high fat fed mice

The incretin hormones, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), are rapidly degraded by dipeptidyl peptidase-4 (DPP-4) to their major circulating metabolites GLP-1(9−36) and GIP(3−42). This study investigates the possible effects of these metabolites, and the equivalent exendin molecule Ex(9−39), on pancreatic islet morphology and constituent alpha and beta cells in high-fat diet (HFD) fed mice. Male Swiss TO-mice (6–8 weeks-old) were maintained on a HFD or normal diet (ND) for 4 months and then received twice-daily subcutaneous injections of GLP-1(9−36), GIP(3−42), Ex(9−39) (25 nmol/kg bw) or saline vehicle (0.9% (w/v) NaCl) over a 60-day period. Metabolic parameters were monitored and excised pancreatic tissues were used for immunohistochemical analysis. Body weight and assessed metabolic indices were not changed by peptide administration. GLP-1(9−36) significantly (p<0.001) increased islet density per mm2 tissue, that was decreased (p<0.05) by HFD. Islet, beta and alpha cell areas were increased (p<0.01) following HFD and subsequently reduced (p<0.01-p<0.001) by GIP(3−42) and Ex(9−39) treatment. While GLP-1(9−36) did not affect islet and beta cell areas in HFD mice, it significantly (p<0.01) decreased alpha cell area. Compared to ND and HFD mice, GIP(3−42) treatment significantly (p<0.05) increased beta cell proliferation. Whilst HFD increased (p<0.001) beta cell apoptosis, this was reduced (p<0.01-p<0.001) by both GLP-1(9−36) and GIP(3−42). These data indicate that the major circulating forms of GLP-1 and GIP, namely GLP-1(9−36) and GIP(3−42) previously considered largely inactive, may directly impact pancreatic morphology, with an important protective effect on beta cell health under conditions of beta cell stress.