Association between pathologic complete response and biochemical indicators after neoadjuvant therapy for HER2-positive breast cancer.

PURPOSE: This study investigated the changes in the fasting blood glucose (FBG), fasting triglyceride (FTG), and fasting total cholesterol (FTC) levels during neoadjuvant therapy (NAT) for human epidermal growth factor receptor 2 (HER2)-positive breast cancer (BC) and the association with pathologic complete response (pCR). METHODS: Relevant data from Sichuan Cancer Hospital from June 2019 to June 2022 were collected and analyzed, and FBG, FTG, and FTC were divided into baseline, change, and process groups, which were grouped to analyze the changes after receiving NAT and the association with pCR. RESULTS: In the estrogen receptor (ER)-negative subgroup, patients with low levels of FTG in the process group were more likely to achieve pCR compared to high levels, and in the progesterone receptor (PR)-negative subgroup, patients with lower FTG compared to higher FTG after receiving NAT was more likely to achieve pCR. CONCLUSIONS: Patients with HER2-positive BC undergoing NAT develop varying degrees of abnormalities (elevated or decreased) in FBG, FTG, and FTC; moreover, the status of FTG levels during NAT may predict pCR in ER-negative or PR-negative HER2-positive BC.Early monitoring and timely intervention for FTG abnormalities may enable this subset of patients to increase the likelihood of obtaining a pCR along with management of abnormal markers.

Hepatocyte-Specific Fads1 Overexpression Attenuates Western Diet-Induced Metabolic Phenotypes in a Rat Model.

Fatty acid desaturase 1 (FADS1) is a rate-limiting enzyme in long-chain polyunsaturated fatty acid (LCPUFA) synthesis. Reduced activity of FADS1 was observed in metabolic dysfunction-associated steatotic liver disease (MASLD). The aim of this study was to determine whether adeno-associated virus serotype 8 (AAV8) mediated hepatocyte-specific overexpression of Fads1 (AAV8-Fads1) attenuates western diet-induced metabolic phenotypes in a rat model. Male weanling Sprague-Dawley rats were fed with a chow diet, or low-fat high-fructose (LFHFr) or high-fat high-fructose diet (HFHFr) ad libitum for 8 weeks. Metabolic phenotypes were evaluated at the endpoint. AAV8-Fads1 injection restored hepatic FADS1 protein levels in both LFHFr and HFHFr-fed rats. While AAV8-Fads1 injection led to improved glucose tolerance and insulin signaling in LFHFr-fed rats, it significantly reduced plasma triglyceride (by ~50%) and hepatic cholesterol levels (by ~25%) in HFHFr-fed rats. Hepatic lipidomics analysis showed that FADS1 activity was rescued by AAV8-FADS1 in HFHFr-fed rats, as shown by the restored arachidonic acid (AA)/dihomo-γ-linolenic acid (DGLA) ratio, and that was associated with reduced monounsaturated fatty acid (MUFA). Our data suggest that the beneficial role of AAV8-Fads1 is likely mediated by the inhibition of fatty acid re-esterification. FADS1 is a promising therapeutic target for MASLD in a diet-dependent manner.

The pan-PPAR agonist lanifibranor improves cardiometabolic health in patients with metabolic dysfunction-associated steatohepatitis.

Lanifibranor, a pan-PPAR agonist, improves liver histology in patients with metabolic dysfunction-associated steatohepatitis (MASH), who have poor cardiometabolic health (CMH) and cardiovascular events as major mortality cause. NATIVE trial secondary and exploratory outcomes (ClinicalTrials.gov NCT03008070) were analyzed for the effect of lanifibranor on IR, lipid and glucose metabolism, systemic inflammation, blood pressure (BP), hepatic steatosis (imaging and histological grading) for all patients of the original analysis. With lanifibranor, triglycerides, HDL-C, apolipoproteins, insulin, HOMA-IR, HbA1c, fasting glucose (FG), hs-CRP, ferritin, diastolic BP and steatosis improved significantly, independent of diabetes status: most patients with prediabetes returned to normal FG levels. Significant adiponectin increases correlated with hepatic and CMH marker improvement; patients had an average weight gain of 2.5 kg, with 49% gaining ≥2.5% weight. Therapeutic benefits were similar regardless of weight change. Here, we show that effects of lanifibranor on liver histology in MASH are accompanied with CMH improvement, indicative of potential cardiovascular clinical benefits.

The proteomic profile is altered but not repaired after bariatric surgery in type 2 diabetes pigs.

To reveal the sources of obesity and type 2 diabetes (T2D) in humans, animal models, mainly rodents, have been used. Here, we propose a pig model of T2D. Weaned piglets were fed high fat/high sugar diet suppling 150% of metabolizable energy. Measurements of weight gain, blood morphology, glucose plasma levels, cholesterol, and triglycerides, as well as glucose tolerance (oral glucose tolerance test, OGTT) were employed to observe T2D development. The histology and mass spectrometry analyses were made post mortem. Within 6 months, the high fat-high sugar (HFHS) fed pigs showed gradual and significant increase in plasma triglycerides and glucose levels in comparison to the controls. Using OGTT test, we found stable glucose intolerance in 10 out of 14 HFHS pigs. Mass spectrometry analysis indicated significant changes in 330 proteins in the intestine, liver, and pancreas of the HFHS pigs. These pigs showed also an increase in DNA base modifications and elevated level of the ALKBH proteins in the tissues. Six diabetic HFHS pigs underwent Scopinaro bariatric surgery restoring glycaemia one month after surgery. In conclusion, a high energy diet applied to piglets resulted in the development of hyperlipidaemia, hyperglycaemia, and type 2 diabetes being reversed by a bariatric procedure, excluding the proteomic profile utill one month after the surgery.

[Exercise promotes irisin expression to ameliorate renal injury in type 2 diabetic rats].

OBJECTIVE: To investigate the role of irisin in exercise-induced improvement of renal function in type 2 diabetic rats. METHODS: Forty male SD rats aged 4-6 weeks were randomized into normal control group, type 2 diabetes mellitus model group, diabetic exercise (DE) group and diabetic irisin (DI) group (n=8). The rats in DE group were trained with treadmill running for 8 weeks, and those in DI group were given scheduled irisin injections for 8 weeks. After the treatments, blood biochemical parameters of the rats were examined, and renal histopathology was observed with HE, Masson and PAS staining. Western blotting was used to detect the protein expression levels in the rats'kidneys. RESULTS: The diabetic rats showed significantly increased levels of fasting insulin, total cholesterol, triglyceride, serum creatinine and blood urea nitrogen with lowered serum irisin level (all P < 0.05). Compared with those in DM group, total cholesterol, triglyceride, serum creatinine and blood urea nitrogen levels were decreased and serum irisin levels were increased in both DE and DI groups (all P < 0.05). The rats in DM group showed obvious structural disorders and collagen fiber deposition in the kidneys, which were significantly improved in DE group and DI group. Both regular exercises and irisin injections significantly ameliorated the reduction of FNDC5, LC3-II/I, Atg7, Beclin-1, p-AMPK, AMPK and SIRT1 protein expressions and lowered of p62 protein expression in the kidneys of the diabetic rats (all P < 0.05). CONCLUSION: Both exercise and exogenous irisin treatment improve nephropathy in type 2 diabetic rats possibly due to irisin-mediated activation of the AMPK/SIRT1 pathway in the kidneys to promote renal autophagy.

PLA2G12A protects against diet-induced obesity and insulin resistance by enhancing energy expenditure and clearance of circulating triglycerides.

Secreted phospholipase A2s are involved in the development of obesity, type 2 diabetes mellitus (T2DM) and cardiovascular disease, which have become serious and growing health concerns worldwide. Integration of genome-wide association study and gene co-expression networks analysis showed that the secreted phospholipase A2 group XIIA (PLA2G12A) may participate in hepatic lipids metabolism. Nevertheless, the role of PLA2G12A in lipid metabolism and its potential mechanism remain elusive. Here, we used AAV9 vector carrying human PLA2G12A gene to exogenously express hPLA2G12A in the liver of mice. We demonstrated that the overexpression of hPLA2G12A resulted in a significant decrease in serum lipid levels in wild-type mice fed with chow diet or high-fat diet (HFD). Moreover, hPLA2G12A treatment protected against diet-induced obesity and insulin resistance in mice fed a HFD. Notably, we found that hPLA2G12A treatment confers protection against obesity and hyperlipidemia independent of its enzymatic activity, but rather by increasing physical activity and energy expenditure. Furthermore, we demonstrated that hPLA2G12A treatment induced upregulation of ApoC2 and Cd36 and downregulation of Angptl8, which contributed to the increase in clearance of circulating triglycerides and hepatic uptake of fatty acids without affecting hepatic de novo lipogenesis, very low-density lipoprotein secretion, or intestinal lipid absorption. Our study highlights the potential of PLA2G12A gene therapy as a promising approach for treating obesity, insulin resistance and T2DM.

Giant organelle vesicles to uncover intracellular membrane mechanics and plasticity.

Tools for accessing and studying organelles remain underdeveloped. Here, we present a method by which giant organelle vesicles (GOVs) are generated by submitting cells to a hypotonic medium followed by plasma membrane breakage. By this means, GOVs ranging from 3 to over 10 µm become available for micromanipulation. GOVs are made from organelles such as the endoplasmic reticulum, endosomes, lysosomes and mitochondria, or in contact with one another such as giant mitochondria-associated ER membrane vesicles. We measure the mechanical properties of each organelle-derived GOV and find that they have distinct properties. In GOVs procured from Cos7 cells, for example, bending rigidities tend to increase from the endoplasmic reticulum to the plasma membrane. We also found that the mechanical properties of giant endoplasmic reticulum vesicles (GERVs) vary depending on their interactions with other organelles or the metabolic state of the cell. Lastly, we demonstrate GERVs' biochemical activity through their capacity to synthesize triglycerides and assemble lipid droplets. These findings underscore the potential of GOVs as valuable tools for studying the biophysics and biology of organelles.

Prenatal Choline Supplementation Improves Glucose Tolerance and Reduces Liver Fat Accumulation in Mouse Offspring Exposed to Ethanol during the Prenatal and Postnatal Periods.

Prenatal alcohol exposure (AE) affects cognitive development. However, it is unclear whether prenatal AE influences the metabolic health of offspring and whether postnatal AE exacerbates metabolic deterioration resulting from prenatal AE. Choline is a semi-essential nutrient that has been demonstrated to mitigate the cognitive impairment of prenatal AE. This study investigated how maternal choline supplementation (CS) may modify the metabolic health of offspring with prenatal and postnatal AE (AE/AE). C57BL/6J female mice were fed either a Lieber-DeCarli diet with 1.4% ethanol between embryonic day (E) 9.5 and E17.5 or a control diet. Choline was supplemented with 4 × concentrations versus the control throughout pregnancy. At postnatal week 7, offspring mice were exposed to 1.4% ethanol for females and 3.9% ethanol for males for 4 weeks. AE/AE increased hepatic triglyceride accumulation in male offspring only, which was normalized by prenatal CS. Prenatal CS also improved glucose tolerance compared to AE/AE animals. AE/AE suppressed hepatic gene expression of peroxisome proliferator activated receptor alpha (Ppara) and low-density lipoprotein receptor (Ldlr), which regulate fatty acid catabolism and cholesterol reuptake, respectively, in male offspring. However, these changes were not rectified by prenatal CS. In conclusion, AE/AE led to an increased risk of steatosis and was partially prevented by prenatal CS in male mice.

Effects of sn-2 Palmitic Triacylglycerols and the Ratio of OPL to OPO in Human Milk Fat Substitute on Metabolic Regulation in Sprague-Dawley Rats.

In this study, the influence of total sn-2 palmitic triacylglycerols (TAGs) and ratio of 1-oleoyl-2-palmitoyl-3-linoleoylglycerol (OPL) to 1,3-dioleoyl-2-palmitoylglycerol (OPO) in human milk fat substitute (HMFS) on the metabolic changes were investigated in Sprague-Dawley rats. Metabolomics and lipidomics profiling analysis indicated that increasing the total sn-2 palmitic TAGs and OPL to OPO ratio in HMFS could significantly influence glycine, serine and threonine metabolism, glycerophospholipid metabolism, glycerolipid metabolism, sphingolipid metabolism, bile acid biosynthesis, and taurine and hypotaurine metabolism pathways in rats after 4 weeks of feeding, which were mainly related to lipid, bile acid and energy metabolism. Meanwhile, the up-regulation of taurine, L-tryptophan, and L-cysteine, and down-regulations of lysoPC (18:0) and hypoxanthine would contribute to the reduction in inflammatory response and oxidative stress, and improvement of immunity function in rats. In addition, analysis of targeted biochemical factors also revealed that HMFS-fed rats had significantly increased levels of anti-inflammatory factor (IL-4), immunoglobulin A (IgA), superoxide dismutase (SOD), and glutathione peroxidase (GSH-px), and decreased levels of pro-inflammatory factors (IL-6 and TNF-α) and malondialdehyde (MDA), compared with those of the control fat-fed rats. Collectively, these observations present new in vivo nutritional evidence for the metabolic regulatory effects of the TAG structure and composition of human milk fat substitutes on the host.

Targeting Non-Alcoholic Fatty Liver Disease with Hawthorn Ethanol Extract (HEE): A Comprehensive Examination of Hepatic Lipid Reduction and Gut Microbiota Modulation.

Recent studies have highlighted the lipid-lowering ability of hawthorn ethanol extract (HEE) and the role played by gut flora in the efficacy of HEE. Our study sought to explore the effects of HEE on non-alcoholic fatty liver disease (NAFLD) in normal flora and pseudo germ-free mice. The results showed that HEE effectively diminished hepatic lipid accumulation, ameliorated liver function, reduced inflammatory cytokine levels and blood lipid profiles, and regulated blood glucose levels. HEE facilitated triglyceride breakdown, suppressed fatty acid synthesis, and enhanced intestinal health by modulating the diversity of the gut microbiota and the production of short-chain fatty acids in the gut. In addition, HEE apparently helps to increase the presence of beneficial genera of bacteria, thereby influencing the composition of the gut microbiota, and the absence of gut flora affects the efficacy of HEE. These findings reveal the potential of hawthorn for the prevention and treatment of NAFLD and provide new perspectives on the study of functional plants to improve liver health.

A short-term rodent model for non-alcoholic steatohepatitis induced by a high-fat diet and carbon tetrachloride.

Several models of mice-fed high-fat diets have been used to trigger non-alcoholic steatohepatitis and some chemical substances, such as carbon tetrachloride. The present study aimed to evaluate the joint action of a high-fat diet and CCl4 in developing a short-term non-alcoholic steatohepatitis model. C57BL6/J mice were divided into two groups: standard diet-fed (SD), the high-fat diet-fed (HFD) and HFD + fructose-fed and carbon tetrachloride (HFD+CCl4). The animals fed with HFD+CCl4 presented increased lipid deposition compared with both SD and HFD mice. Plasma cholesterol was increased in animals from the HFD+CCl4 group compared with the SD and HFD groups, without significant differences between the SD and HFD groups. Plasma triglycerides showed no significant difference between the groups. The HFD+CCl4 animals had increased collagen deposition in the liver compared with both SD and HFD groups. Hydroxyproline was also increased in the HFD+CCl4 group. Liver enzymes, alanine aminotransferase and aspartate aminotransferase, were increased in the HFD+CCl4 group, compared with SD and HFD groups. Also, CCl4 was able to trigger an inflammatory process in the liver of HFD-fed animals by promoting an increase of ∼2 times in macrophage activity, ∼6 times in F4/80 gene expression, and pro-inflammatory cytokines (IL-1b and TNFa), in addition to an increase in inflammatory pathway protein phosphorylation (IKKbp). HFD e HFD+CCl4 animals increased glucose intolerance compared with SD mice, associated with reduced insulin-stimulated AKT activity in the liver. Therefore, our study has shown that short-term HFD feeding associated with fructose and CCl4 can trigger non-alcoholic steatohepatitis and cause damage to glucose metabolism.

MiR-103-5p deficiency suppresses lipid accumulation via upregulating PLSCR4 and its host gene PANK3 in goat mammary epithelial cells.

Lipids are intimately related to the unique flavor and nutritional values of goat milk. MicroRNAs (miRNA) participate in the regulation of various biological functions, including the synthesis and degradation of lipids. Several studies have shown that miR-103 is involved in the regulation of lipid metabolism, however, the molecular mechanism by which miR-103 regulates lipid metabolism in goat mammary gland is poorly understood. In this study, miR-103 was knocked out in goat mammary epithelial cells (GMECs) by CRISPR/Cas9, and the accumulation of lipid droplets, triglycerides, and cholesterol in the cells was suppressed subsequently. Overexpression or knockdown of miR-103-5p and miR-103-3p in GMECs revealed that it was miR-103-5p that promoted lipid accumulation but not miR-103-3p. In addition, Pantothenate Kinase 3 (PANK3), the host gene of miR-103, and Phospholipid Scramblase 4 (PLSCR4) were identified as the target genes of miR-103-5p by dual fluorescein and miRNA pulldown. Furthermore, we identified that cellular lipid levels were negatively regulated by PANK3 and PLSCR4. Lastly, in miR-103 knockout GMECs, the knockdown of PANK and PLSCR4 rescued the lipid accumulation. These findings suggest that miR-103-5p promotes lipid accumulation by targeting PLSCR4 and the host gene PANK3 in GMECs, providing new insights for the regulation of goat milk lipids via miRNAs.

Integration of network pharmacology, lipidomics, and transcriptomics analysis to reveal the mechanisms underlying the amelioration of AKT-induced nonalcoholic fatty liver disease by total flavonoids in vine tea.

Nonalcoholic fatty liver disease (NAFLD) is the main reason for chronic liver diseases and malignancies. Currently, there is a lack of approved drugs for the prevention or treatment of NAFLD. Vine tea (Ampelopsis grossedentata) has been used as a traditional Chinese beverage for centuries. Vine tea carries out several biological activities including the regulation of plasma lipids and blood glucose, hepato-protective function, and anti-tumor activity and contains the highest content of flavonoids. However, the underlying mechanisms of total flavonoids from vine tea (TF) in the attenuation of NAFLD remain unclear. Therefore, we investigated the interventions and mechanisms of TF in mice with NAFLD using an integrated analysis of network pharmacology, lipidomics, and transcriptomics. Staining and biochemical tests revealed a significant increase in AKT-overexpression-induced (abbreviated as AKT-induced) NAFLD in mice. Lipid accumulation in hepatic intracellular vacuoles was alleviated after TF treatment. In addition, TF reduced the hepatic and serum triglyceride levels in mice with AKT-induced NAFLD. Lipidomics results showed 32 differential lipids in the liver, mainly including triglycerides (TG), diglycerides (DG), phosphatidylcholine (PC), and phosphatidylethanolamine (PE). Transcriptomic analysis revealed that 314 differentially expressed genes were commonly upregulated in the AKT group and downregulated in the TF group. The differential regulation of lipids by the genes Pparg, Scd1, Chpt1, Dgkz, and Pla2g12b was further revealed by network enrichment analysis and confirmed by RT-qPCR. Furthermore, we used immunohistochemistry (IHC) to detect changes in the protein levels of the key proteins PPARγ and SCD1. In summary, TF can improve hepatic steatosis by targeting the PPAR signaling pathway, thereby reducing de novo fatty acid synthesis and modulating the glycerophospholipid metabolism.

[Effect of Erchen Decoction on liver mitochondrial function by inhibiting mTORC1/SREBP1/CAV1 pathway in mice with high-fat diet].

This study aims to investigate the effect of Erchen Decoction(ECD) on liver mitochondrial function in mice with a high-fat diet and its possible mechanism. A total of sixty C57BL/6J mice were randomly divided into a normal group, high-fat group, ECD group, mTORC1 activator(MHY) group, ECD+MHY group, and polyene phosphatidyl choline(PPC) group, with 10 rats in each group. The normal group was given a normal diet, and the other groups were fed a high-fat diet for 20 weeks. At the 17th week, the ECD group and ECD+MHY group were given ECD(8.7 g·kg~(-1)) daily, and the PPC group was given PPC(0.18 g·kg~(-1)) daily, while the remaining groups were given normal saline(0.01 mL·g~(-1)) daily for four weeks. In the 19th week, the MHY group and ECD+MHY group were injected intraperitoneally with MHY(5 mg·kg~(-1)) every other day for two weeks. During the experiment, the general conditions of the mice were observed. The contents of triglyceride(TG) and total cholesterol(TC) in serum were measured. Morphological changes in liver tissue were examined through HE and oil red O staining. The content of adenosine triphosphate(ATP) was determined using chemiluminescence, and mitochondrial membrane potential was assessed using a fluorescence probe(JC-1). Western blot was performed to detect the expression of rapamycin target protein complex 1(mTOR1), ribosomal protein S6 kinase B1(S6K), sterol regulatory element binding protein 1(SREBP1), and caveolin 1(CAV1). RESULTS:: revealed that compared with the normal group, the mice in the high-fat group exhibited significant increases in body weight and abdominal circumference(P<0.01). Additionally, there were significant increases in TG and TC levels(P<0.01). HE and oil red O staining showed that the boundaries of hepatic lobules were unclear; hepatocytes were enlarged, round, and irregularly arranged, with obvious lipid droplet deposition and inflammatory cell infiltration. The liver ATP content and mitochondrial membrane potential decreased significantly(P<0.01). The expression of p-mTOR, p-S6K, and n-SREBP1 increased significantly(P<0.01), while the expression of CAV1 decreased significantly(P<0.01). Compared with the high-fat group, the body weight and TG content of mice in the ECD group and PPC group decreased significantly(P<0.05). Improvements were observed in hepatocyte morphology, lipid deposition, and inflammatory cell infiltration. Furthermore, there were significant increases in ATP content and mitochondrial membrane potential(P<0.05 or P<0.01). The expression of p-mTOR, p-S6K, and n-SREBP1 decreased significantly in the ECD group(P<0.01), while CAV1 expression increased significantly(P<0.01). However, the indices mentioned above did not show improvement in the MHY group. When the ECD+MHY group was compared with the MHY group, there were significant reductions in body weight and TG contents(P<0.05). The morphological changes of hepatocytes, lipid deposition, and inflammatory cell infiltration were recovered. Moreover, there were significant increases in liver ATP content and mitochondrial membrane potential(P<0.05 or P<0.05). The expression of p-mTOR, p-S6K, and n-SREBP1 decreased significantly(P<0.01), while CAV1 expression increased significantly(P<0.01). In conclusion, ECD can improve mitochondrial function by regulating the mTORC1/SREBP1/CAV1 pathway. This mechanism may be involved in the resolution of phlegm syndrome and the regulation of lipid metabolism.

Liproxstatin-1 attenuates acute hypertriglyceridemic pancreatitis through inhibiting ferroptosis in rats.

Ferroptosis is closely associated with inflammatory diseases, including acute pancreatitis (AP); however, the involvement of ferroptosis in hypertriglyceridemic pancreatitis (HTGP) remains unclear. In the present study, we aimed to explore the relationship between lipid metabolism and ferroptosis in HTGP and the alleviating effect of liproxstatin-1 (Lip-1) in vivo. This study represents the first exploration of lipid metabolism and endoplasmic reticulum stress (ERS) in HTGP, targeting ferroptosis as a key factor in HTGP. Hypertriglyceridemia (HTG) was induced under high-fat diet conditions. Cerulein was then injected to establish AP and HTGP models. Lip-1, a specific ferroptosis inhibitor, was administered before the induction of AP and HTGP in rats, respectively. Serum triglyceride, amylase, inflammatory factors, pathological and ultrastructural structures, lipid peroxidation, and iron overload indicators related to ferroptosis were tested. Moreover, the interaction between ferroptosis and ERS was assessed. We found HTG can exacerbate the development of AP, with an increased inflammatory response and intensified ferroptosis process. Lip-1 treatment can attenuate pancreatic injury by inhibiting ferroptosis through lipid metabolism and further resisting activations of ERS-related proteins. Totally, our results proved lipid metabolism can promote ferroptosis in HTGP by regulating ACSL4/LPCAT3 protein levels. Additionally, ERS may participate in ferroptosis via the Bip/p-EIF2α/CHOP pathway, followed by the alleviating effect of Lip-1 in the rat model.

Narirutin-Rich Celluclast Extract from Mandarin (Citrus unshiu) Peel Alleviates High-Fat Diet-Induced Obesity and Promotes Energy Metabolism in C57BL/6 Mice.

Mandarin peel, a main by-product from the processing of citrus juice, has been highlighted for its various bioactivities and functional ingredients. Our previous study proved the inhibitory effects of Celluclast extract from mandarin peel (MPCE) on lipid accumulation and differentiation in 3T3-L1 adipocytes. Therefore, the current study aimed to evaluate the anti-obesity effect of MPCE in high-fat diet (HFD)-induced obese mice. The high-performance liquid chromatography (HPLC) analysis exhibited that narirutin and hesperidin are the main active components of MPCE. Our current results showed that MPCE supplementation decreased adiposity by reducing body and organ weights in HFD-induced obese mice. MPCE also reduced triglyceride (TG), alanine transaminase (ALT), aspartate transaminase (AST), and leptin contents in the serum of HFD-fed mice. Moreover, MPCE significantly inhibited hepatic lipid accumulation by regulating the expression levels of proteins associated with lipid metabolism, including sterol regulatory element-binding protein (SREBP1c), fatty acid synthase (FAS), and acetyl-CoA carboxylase (ACC). Furthermore, MPCE administration significantly inhibited both adipogenesis and lipogenesis, with modulation of energy metabolism by activating 5' adenosine monophosphate-activated protein kinase (AMPK) and lipolytic enzymes such as hormone-sensitive lipase (HSL) in the white adipose tissue (WAT). Altogether, our findings indicate that MPCE improves HFD-induced obesity and can be used as a curative agent in pharmaceuticals and nutraceuticals to alleviate obesity and related disorders.

Biochemical characterization of acyl-CoA:diacylglycerol acyltransferase2 from the diatom Phaeodactylum tricornutum and its potential effect on LC-PUFAs biosynthesis in planta.

BACKGROUND: Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), belonging to ω-3 long-chain polyunsaturated fatty acids (ω3-LC-PUFAs), are essential components of human diet. They are mainly supplemented by marine fish consumption, although their native producers are oleaginous microalgae. Currently, increasing demand for fish oils is insufficient to meet the entire global needs, which puts pressure on searching for the alternative solutions. One possibility may be metabolic engineering of plants with an introduced enzymatic pathway producing ω3-LC-PUFAs. RESULT: In this study we focused on the acyl-CoA:diacylglycerol acyltransferase2b (PtDGAT2b) from the diatom Phaeodactylum tricornutum, an enzyme responsible for triacylglycerol (TAG) biosynthesis via acyl-CoA-dependent pathway. Gene encoding PtDGAT2b, incorporated into TAG-deficient yeast strain H1246, was used to confirm its activity and conduct biochemical characterization. PtDGAT2b exhibited a broad acyl-CoA preference with both di-16:0-DAG and di-18:1-DAG, whereas di-18:1-DAG was favored. The highest preference for acyl donors was observed for 16:1-, 10:0- and 12:0-CoA. PtDGAT2b also very efficiently utilized CoA-conjugated ω-3 LC-PUFAs (stearidonic acid, eicosatetraenoic acid and EPA). Additionally, verification of the potential role of PtDGAT2b in planta, through its transient expression in tobacco leaves, indicated increased TAG production with its relative amount increasing to 8%. Its co-expression with the gene combinations aimed at EPA biosynthesis led to, beside elevated TAG accumulation, efficient accumulation of EPA which constituted even 25.1% of synthesized non-native fatty acids (9.2% of all fatty acids in TAG pool). CONCLUSIONS: This set of experiments provides a comprehensive biochemical characterization of DGAT enzyme from marine microalgae. Additionally, this study elucidates that PtDGAT2b can be used successfully in metabolic engineering of plants designed to obtain a boosted TAG level, enriched not only in ω-3 LC-PUFAs but also in medium-chain and ω-7 fatty acids.

Medium-chain triglyceride-specific appetite is regulated by the ß-oxidation of medium-chain fatty acids in the liver.

Most studies on fat appetite have focused on long-chain triglycerides (LCTs) due to their obesogenic properties. Medium-chain triglycerides (MCTs), conversely, exhibit antiobesogenic effects; however, the regulation of MCT intake remains elusive. Here, we demonstrate that mice can distinguish between MCTs and LCTs, and the specific appetite for MCTs is governed by hepatic ß-oxidation. We generated liver-specific medium-chain acyl-CoA dehydrogenase (MCAD)-deficient (MCADL-/-) mice and analyzed their preference for MCT and LCT solutions using glyceryl trioctanoate (C8-TG), glyceryl tridecanoate (C10-TG), corn oil, and lard oil in two-bottle choice tests conducted over 8 days. In addition, we used lick microstructure analyses to evaluate the palatability and appetite for MCT and LCT solutions. Finally, we measured the expression levels of genes associated with fat ingestion (Galanin, Qrfp, and Nmu) in the hypothalamus 2 h after oral gavage of fat. Compared with control mice, MCADL-/- mice exhibited a significantly reduced preference for MCT solutions, with no alteration in the preference for LCTs. Lick analysis revealed that MCADL-/- mice displayed a significantly decreased appetite for MCT solutions only while the palatability of both MCT and LCT solutions remained unaffected. Hypothalamic Galanin expression in control mice was elevated by oral gavage of C8-TG but not by LCTs, and this response was abrogated in MCADL-/- mice. In summary, our data suggest that hepatic ß-oxidation is required for MCT-specific appetite but not for LCT-specific appetite. The induction of hypothalamic galanin upon MCT ingestion, dependent on hepatic ß-oxidation, could be involved in the regulation of MCT-specific appetite.NEW & NOTEWORTHY Whether and how medium-chain triglyceride (MCT) intake is regulated remains unknown. Here, we showed that mice can discriminate between MCTs and LCTs. Hepatic ß-oxidation participates in MCT-specific appetite, and hypothalamic galanin may be one of the factors that regulate MCT intake. Because of the antiobesity effects of MCTs, studying MCT-specific appetite may help combat obesity by promoting the intake of MCTs instead of LCTs.

Lysosomal diacylglycerol pyrophosphate phosphatase is not essential in Trypanosoma brucei.

Mg2+-independent phosphatidic acid phosphatase (PAP2), diacylglycerol pyrophosphate phosphatase 1 (Dpp1) is a membrane-associated enzyme in Saccharomyces cerevisiae. The enzyme is responsible for inducing the breakdown of ß-phosphate from diacylglycerol pyrophosphate (DGPP) into phosphatidate (PA) and then removes the phosphate from PA to give diacylglycerol (DAG). In this study through RNAi suppression, we have demonstrated that Trypanosoma brucei diacylglycerol pyrophosphate phosphatase 1 (TbDpp1) procyclic form production is not required for parasite survival in culture. The steady-state levels of triacylglycerol (TAG), the number of lipid droplets, and the PA content are all maintained constant through the inducible down-regulation of TbDpp1. Furthermore, the localization of C-terminally tagged variants of TbDpp1 in the lysosome was demonstrated by immunofluorescence microscopy.

Differences in diacylglycerol acyltransferases expression patterns and regulation cause distinct hepatic triglyceride deposition in fish.

Triglyceride (TAG) deposition in the liver is associated with metabolic disorders. In lower vertebrate, the propensity to accumulate hepatic TAG varies widely among fish species. Diacylglycerol acyltransferases (DGAT1 and DGAT2) are major enzymes for TAG synthesis. Here we show that large yellow croaker (Larimichthys crocea) has significantly higher hepatic TAG level than that in rainbow trout (Oncorhynchus mykiss) fed with same diet. Hepatic expression of DGATs genes in croaker is markedly higher compared with trout under physiological condition. Meanwhile, DGAT1 and DGAT2 in both croaker and trout are required for TAG synthesis and lipid droplet formation in vitro. Furthermore, oleic acid treatment increases DGAT1 expression in croaker hepatocytes rather than in trout and has no significant difference in DGAT2 expression in two fish species. Finally, effects of various transcription factors on croaker and trout DGAT1 promoter are studied. We find that DGAT1 is a target gene of the transcription factor CREBH in croaker rather than in trout. Overall, hepatic expression and transcriptional regulation of DGATs display significant species differences between croaker and trout with distinct hepatic triglyceride deposition, which bring new perspectives on the use of fish models for studying hepatic TAG deposition.