Hormone-sensitive lipase: control of intracellular tri-(di-)acylglycerol and cholesteryl ester hydrolysis

Anti-obesity effects of Celosia cristata flower extract in vitro and in vivo

BACKGROUND

The overstoring of surplus calories in mature adipocytes causes obesity and abnormal metabolic activity. The anti-obesity effect of a Celosia cristata (CC) total flower extract was assessed in vitro, using 3T3-L1 pre-adipocytes and mouse adipose-derived stem cells (ADSCs), and in vivo, using high-fat diet (HFD)-treated C57BL/6 male mice.

METHODS

CC extract was co-incubated during adipogenesis in both 3T3-L1 cells and ADSCs. After differentiation, lipid droplets were assessed by oil red O staining, adipogenesis and lipolytic factors were evaluated, and intracellular triglyceride and glycerol concentrations were analyzed. For in vivo experiments, histomorphological analysis, mRNA expression levels of adipogenic and lipolytic factors in adipose tissue, blood plasma analysis, metabolic profiles were investigated.

RESULTS

CC treatment significantly prevented adipocyte differentiation and lipid droplet accumulation, reducing adipogenesis-related factors and increasing lipolysis-related factors. Consequently, the intracellular triacylglycerol content was diminished, whereas the glycerol concentration in the cell supernatant increased. Mice fed an HFD supplemented with the CC extract exhibited decreased HFD-induced weight gain with metabolic abnormalities such as intrahepatic lipid accumulation and adipocyte hypertrophy. Improved glucose utilization and insulin sensitivity were observed, accompanied by the amelioration of metabolic disturbances, including alterations in liver enzymes and lipid profiles, in CC-treated mice. Moreover, the CC extract helped restore the disrupted energy metabolism induced by the HFD, based on a metabolic animal monitoring system.

CONCLUSION

This study suggests that CC total flower extract is a potential natural herbal supplement for the prevention and management of obesity.

Transcriptional and physiological profiles reveal the respiratory, antioxidant and metabolic adaption to intermittent hypoxia in the clam Tegillarca granosa

Tegillarca granosa can survive intermittent hypoxia for a long-term. We used the clam T. granosa as model to investigate the respiratory, antioxidant and metabolic responses to consecutive hypoxia-reoxygenation (H/R) stress at both physiological and transcriptional levels. The results showed that the clams were able to rapidly regulate oxygen consumption and ammonia excretion during H/R stress, and alleviate oxidative stress during the second-time challenge. The clams also efficiently balanced energy metabolism through the rapid conversion and decomposition of glycogen. According to the transcriptome profile, KEGG pathways of starch and sucrose metabolism, ECM-receptor interaction, and protein processing in endoplasmic reticulum were significantly enriched in H group (the second-time 24 h hypoxia exposure), while pathways associated with lipid metabolism were significantly enriched in h group (the first-time 24 h hypoxia exposure). DEGs including hspa5, birc2/3, and map3k5 might play important roles in alleviating endoplasmic reticulum stress, cpla2 and pla2g16 might mitigate oxidative stress by adjusting the composition of cellular membrane. In conclusions, our findings suggest that rapid adjustment of oxygen consumption, ammonia metabolism, glycogen metabolism, and the ability to adjust the composition of the membrane lipid may be critical for T. granosa in maintaining energy homeostasis and reducing oxidative damage during intermittent H/R exposure. This study preliminarily clarified the response of T. granosa to intermittent hypoxia stress on the physiological and molecular levels, offering insights into the hypoxia-tolerant mechanisms in this species and providing a reference for the following study on the other hypoxic-tolerant species.

Plasma fatty acid esters of hydroxy fatty acids and surrogate fatty acid esters of hydroxy fatty acids hydrolysis activity in children with or without obesity and in adults with or without coronary artery disease

AIM

Fatty acid esters of hydroxy fatty acids (FAHFA) are a class of bioactive lipids with anti-inflammatory, antidiabetic and cardioprotective properties. FAHFA hydrolysis into its fatty acid (FA) and hydroxy fatty acid (HFA) constituents can affect the bioavailability of FAHFA and its subsequent biological effects. We aimed to investigate FAHFA levels and FAHFA hydrolysis activity in children with or without obesity, and in adults with or without coronary artery disease (CAD).

MATERIALS AND METHODS

Our study cohort included 20 children without obesity, 40 children with obesity, 10 adults without CAD and 28 adults with CAD. We quantitated plasma levels of four families of FAHFA [palmitic acid hydroxy stearic acid (PAHSA), palmitoleic acid hydroxy stearic acid (POHSA), oleic acid hydroxy stearic acid (OAHSA), stearic acid hydroxy stearic acid] and their corresponding FA and HFA constituents using liquid chromatography-tandem mass spectrometry analysis. Surrogate FAHFA hydrolysis activity was estimated as the FA/FAHFA or HFA/FAHFA ratio.

RESULTS

Children with obesity had lower plasma PAHSA (p = .001), OAHSA (p = .006) and total FAHFA (p = .011) levels, and higher surrogate FAHFA hydrolysis activity represented by PA/PAHSA (p = .040) and HSA/OAHSA (p = .025) compared with children without obesity. Adults with CAD and a history of myocardial infarction (MI) had lower POHSA levels (p = .026) and higher PA/PAHSA (p = .041), POA/POHSA (p = .003) and HSA/POHSA (p = .038) compared with those without MI.

CONCLUSION

Altered FAHFA metabolism is associated with obesity and MI, and inhibition of FAHFA hydrolysis should be studied further as a possible therapeutic strategy in obesity and MI.

Role of carboxylesterase and arylacetamide deacetylase in drug metabolism, physiology, and pathology

Carboxylesterases (CES1 and CES2) and arylacetamide deacetylase (AADAC), which are expressed primarily in the liver and/or gastrointestinal tract, hydrolyze drugs containing ester and amide bonds in their chemical structure. These enzymes often catalyze the conversion of prodrugs, including the COVID-19 drugs remdesivir and molnupiravir, to their pharmacologically active forms. Information on the substrate specificity and inhibitory properties of these enzymes, which would be useful for drug development and toxicity avoidance, has accumulated. Recently,in vitroandin vivostudies have shown that these enzymes are involved not only in drug hydrolysis but also in lipid metabolism. CES1 and CES2 are capable of hydrolyzing triacylglycerol, and the deletion of their orthologous genes in mice has been associated with impaired lipid metabolism and hepatic steatosis. Adeno-associated virus-mediated human CES overexpression decreases hepatic triacylglycerol levels and increases fatty acid oxidation in mice. It has also been shown that overexpression of CES enzymes or AADAC in cultured cells suppresses the intracellular accumulation of triacylglycerol. Recent reports indicate that AADAC can be up- or downregulated in tumors of various organs, and its varied expression is associated with poor prognosis in patients with cancer. Thus, CES and AADAC not only determine drug efficacy and toxicity but are also involved in pathophysiology. This review summarizes recent findings on the roles of CES and AADAC in drug metabolism, physiology, and pathology.

Molecular insights into the lipid-carbohydrates metabolism switch under the endurance effort in Arabian horses

BACKGROUND

Recent studies have shown that in Arabian horse muscle, long-term exercise-induced expression of genes related to fatty acid degradation and the downregulation of genes belonging to the glycolysis/gluconeogenesis and insulin signalling pathways. Long-lasting physical exertion may trigger the metabolism to switch the main energy source from carbohydrates to lipids due to higher caloric content.

OBJECTIVES

To describe the metabolism adaptation at the whole transcriptome of blood to endurance effort in Arabian horses.

STUDY DESIGN

In vivo experiment.

METHODS

Venous blood samples from 10 Arabian horses were taken before and after a 120 km long endurance ride to isolate the RNA and perform the high-throughput NGS transcriptome sequencing.

RESULTS

The results, including KEGG (Kyoto Encyclopaedia of Genes and Genomes) and GO (Gene Ontology) analyses, allowed us to describe the most significantly upregulated-ARV1, DGAT2, LIPE, APOA2, MOGAT1, MOGAT2, GYS1, GYS2 and downregulated-ACACA, ACACB, FADS1, FADS2 genes involved in carbohydrate and lipid metabolism. Also, the increased expression of RAF1, KRAS and NRAS genes involved in the Insulin pathway and PI3K-Akt was shown.

MAIN LIMITATIONS

Limited sample size, Arabians used for endurance racing were not compared to Arabians from other equestrian disciplines.

CONCLUSIONS

This general insight into the processes described supports the thesis of the lipid-carbohydrates metabolism switch in endurance Arabian horses and provides the basis for further research.

Inhibition of visceral adipose tissue-derived pathogenic signals by activation of adenosine A2AR improves hepatic and cardiac dysfunction of NASH mice

A2AR-disrupted mice is characterized by severe systemic and visceral adipose tissue (VAT) inflammation. Increasing adenosine cyclase (AC), cAMP, and protein kinase A (PKA) formation through A2AR activation suppress systemic/VAT inflammation in obese mice. This study explores the effects of 4 wk A2AR agonist PSB0777 treatment on the VAT-driven pathogenic signals in hepatic and cardiac dysfunction of nonalcoholic steatohepatitis (NASH) obese mice. Among NASH mice with cardiac dysfunction, simultaneous decrease in the A2AR, AC, cAMP, and PKA levels were observed in VAT, liver, and heart. PSB0777 treatment significantly restores AC, cAMP, PKA, and hormone-sensitive lipase (HSL) levels, decreased SREBP-1/FASN, MCP-1, and CD68 levels, reduces infiltrated CD11b+ F4/80+ cells and adipogenesis in VAT of NASH + PSB0777 mice. The changes in VAT were accompanied by the suppression of hepatic and cardiac lipogenic/inflammatory/injury/apoptotic/fibrotic markers, the normalization of cardiac contractile [sarco/endoplasmic reticulum Ca2+ ATPase (SERCA2)] marker, and cardiac dysfunction. The in vitro approach revealed that conditioned media (CM) of VAT of NASH mice (CMnash) trigger palmitic acid (PA)-like lipotoxic (lipogenic/inflammatory/apoptotic/fibrotic) effects in AML-12 and H9c2 cell systems. Significantly, A2AR agonist pretreatment-related normalization of A2AR-AC-cAMP-PKA levels was associated with the attenuation of CMnash-related upregulation of lipotoxic markers and the normalization of lipolytic (AML-12 cells) or contractile (H9C2 cells) marker/contraction. The in vivo and in vitro experiments revealed that A2AR agonists are potential agent to inhibit the effects of VAT inflammation-driven pathogenic signals on the hepatic and cardiac lipogenesis, inflammation, injury, apoptosis, fibrosis, hypocontractility, and subsequently improve hepatic and cardiac dysfunction in NASH mice.NEW & NOTEWORTHY Protective role of adenosine A2AR receptor (A2AR) and AC-cAMP-PKA signaling against nonalcoholic fatty liver disease (NAFLD)/nonalcoholic steatohepatitis (NASH) possibly via its actions on adipocytes is well known in the past decade. Thus, this study evaluates pharmacological activities of A2AR agonist PSB0777, which has already demonstrated to treat NASH. In this study, the inhibition of visceral adipose tissue-derived pathogenic signals by activation of adenosine A2AR with A2AR agonist PSB0777 improves the hepatic and cardiac dysfunction of high-fat diet (HFD)-induced NASH mice.

Tissue fibrosis associated depletion of lipid-filled cells

Fibrosis is primarily described as the deposition of excessive extracellular matrix, but in many tissues it also involves a loss of lipid or lipid-filled cells. Lipid-filled cells are critical to tissue function and integrity in many tissues including the skin and lungs. Thus, loss or depletion of lipid-filled cells during fibrogenesis, has implications for tissue function. In some contexts, lipid-filled cells can impact ECM composition and stability, highlighting their importance in fibrotic transformation. Recent papers in fibrosis address this newly recognized fibrotic lipodystrophy phenomenon. Even in disparate tissues, common mechanisms are emerging to explain fibrotic lipodystrophy. These findings have implications for fibrosis in tissues composed of fibroblast and lipid-filled cell populations such as skin, lung, and liver. In this review, we will discuss the roles of lipid-containing cells, their reduction/loss during fibrotic transformation, and the mechanisms of that loss in the skin and lungs.

Extracellular macrophage migration inhibitory factor (MIF) downregulates adipose hormone-sensitive lipase (HSL) and contributes to obesity

Attenuation of adipose hormone sensitive lipase (HSL) may impair lipolysis and exacerbate obesity. We investigate the role of cytokine, macrophage migration inhibitory factor (MIF) in regulating adipose HSL and adipocyte hypertrophy. Extracellular MIF downregulates HSL in an autocrine fashion, by activating the AMPK/JNK signaling pathway upon binding to its membrane receptor, CD74. WT mice fed high fat diet (HFD), as well as mice overexpressing MIF, both had high circulating MIF levels and showed suppression of HSL during the development of obesity. Blocking the extracellular action of MIF by a neutralizing MIF antibody significantly reduced obesity in HFD mice. Interestingly, intracellular MIF binds with COP9 signalosome subunit 5 (Csn5) and JNK, which leads to an opposing effect to inhibit JNK phosphorylation. With global MIF deletion, adipocyte JNK phosphorylation increased, resulting in decreased HSL expression, suggesting that the loss of MIF's intracellular inhibitory action on JNK was dominant in Mif-/- mice. Adipose tissue from Mif-/- mice also exhibited higher Akt and lower PKA phosphorylation following HFD feeding compared with WT, which may contribute to the downregulation of HSL activation during more severe obesity. Both intracellular and extracellular MIF have opposing effects to regulate HSL, but extracellular actions predominate to downregulate HSL and exacerbate the development of obesity during HFD.

Anti‑adipogenic effect and underlying mechanism of lignan‑enriched nutmeg extract on 3T3‑L1 preadipocytes

Nutmeg is the seed derived from Myristica fragrans. Nutmeg seeds contain alkylbenzene derivatives such as myristicin, which are toxic to the human organism, and lignan compounds such as nectandrin B, which possess anti-aging and anti-diabetic properties. However, the anti-adipogenic, prolipolytic and anti-inflammatory effects of lignan-enriched nutmeg extract (LNX) on preadipocytes remain unclear. In the present study, the effects of LNX on lipid accumulation, glycerol release and inflammatory cyclooxygenase-2 (COX-2) expression in differentiated 3T3-L1 preadipocytes were investigated. Oil red O staining demonstrated that treatment with LNX resulted in a concentration-dependent reduction in lipid accumulation in differentiating 3T3-L1 preadipocytes without affecting cell growth. Mechanistically, LNX treatment at 6 µg/ml led to a reduction in phosphorylation levels of signal transducer and activator of transcription 3 (STAT3), whereas it did not influence the peroxisome proliferator-activated receptor gamma (PPAR-γ) and CCAAT enhancer binding protein alpha (C/EBP-α) expression levels during 3T3-L1 preadipocyte differentiation. In addition, LNX treatment at 6 µg/ml led to a decrease in fatty acid synthase (FAS) expression levels on day (D) 2, but not D5 and D8, during preadipocyte differentiation. Treatment with LNX at 6 µg/ml did not affect the expression levels of perilipin A during preadipocyte differentiation. In differentiated 3T3-L1 adipocytes, LNX treatment at 6 µg/ml did not stimulate glycerol release and hormone-sensitive lipase phosphorylation, which are known lipolysis hallmarks. Furthermore, LNX treatment at the doses tested had no effect on tumor necrosis factor alpha-induced COX-2 expression in 3T3-L1 preadipocytes. Collectively, these results demonstrated that LNX has an anti-adipogenic effect on differentiating 3T3-L1 preadipocytes, which is mediated by the downregulation of STAT3 phosphorylation and FAS expression.

The determinants of fasting and post-load non-esterified fatty acids in older adults: The cardiovascular health study

Aim

Non-esterified fatty acids (NEFA) are potential targets for prevention of key cardiometabolic diseases of aging, but their population-level correlates remain uncertain. We sought to identify modifiable factors associated with fasting and post-load NEFA levels in older adults.

Methods

We used linear regression to determine the cross-sectional associations of demographic, anthropometric, and lifestyle characteristics and medication use with serum fasting and post-load NEFA concentrations amongst community-dwelling older adults enrolled in the Cardiovascular Health Study (n = 1924).

Results

Fasting NEFA levels generally demonstrated a broader set of determinants, while post-load NEFA were more consistently associated with metabolic factors. Waist circumference and weight were associated with higher fasting and post-load NEFA. Cigarette smoking and caffeine intake were associated with lower levels of both species, and moderate alcohol intake was associated with higher fasting levels whereas greater consumption was associated with lower post-load levels. Unique factors associated with higher fasting NEFA included female sex, higher age, loop and thiazide diuretic use and calcium intake, while factors associated with lower fasting levels included higher educational attainment, beta-blocker use, and protein intake. Hours spent sleeping during the daytime were associated with higher post-load NEFA, while DASH score was associated with lower levels.

Conclusion

Fasting and post-load NEFA have both common and unique modifiable risk factors, including sociodemographics, anthropometric, medications, and diet. Post-load NEFA were particularly sensitive to metabolic factors, while a broader range of determinants were associated with fasting levels. These factors warrant study as targets for lowering levels of NEFA in older adults.

MicroRNA regulation of adrenal glucocorticoid and androgen biosynthesis

Steroid hormones are derived from a common precursor molecule, cholesterol, and regulate a wide range of physiologic function including reproduction, salt balance, maintenance of secondary sexual characteristics, response to stress, neuronal function, and various metabolic processes. Among the steroids synthesized by the adrenal and gonadal tissues, adrenal mineralocorticoids, and glucocorticoids are essential for life. The process of steroidogenesis is regulated at multiple levels largely by transcriptional, posttranscriptional, translational, and posttranslational regulation of the steroidogenic enzymes (i.e., cytochrome P450s and hydroxysteroid dehydrogenases), cellular compartmentalization of the steroidogenic enzymes, and cholesterol processing and transport proteins. In recent years, small noncoding RNAs, termed microRNAs (miRNAs) have been recognized as major post-transcriptional regulators of gene expression with essential roles in numerous biological processes and disease pathologies. Although their role in the regulation of steroidogenesis is still emerging, several recent studies have contributed significantly to our understanding of the role miRNAs play in the regulation of the steroidogenic process. This chapter focuses on the recent developments in miRNA regulation of adrenal glucocorticoid and androgen production in humans and rodents.

Clinical characteristics and severity of diabetic ketoacidosis: A cross-sectional study from a tertiary hospital in Ghana

OBJECTIVES

Diabetic ketoacidosis (DKA) is a common, severe and often fatal complication of diabetes. This study aimed to investigate the clinical characteristics and precipitants of DKA, as well as factors associated with DKA severity in Ghanaian patients.

METHODS

Cross-sectional study of the medical records of all 70 adult patients >18 years managed for DKA in the adult emergency room of Korle-Bu Teaching Hospital in Ghana from March 2019 to July 2019. DKA diagnosis was based on hyperglycaemia >11.0 mmol/L, ketonuria (more than 2+) plus acidaemia of (pH < 7.3) or bicarbonate (HCO3 - ) <15.0 mmol/L. However, when serum bicarbonate and pH were not available, clinical signs of acidosis, for example, Kussmaul breathing aided in the diagnosis. DKA severity was assessed based on the Joint British Diabetes Societies (JBDS) guidelines of factors suggestive of severe DKA. Multivariable logistic regression was used to determine the factors associated with DKA severity. Odds ratio and 95% confidence interval for factors associated with DKA severity were determined.

RESULTS

The mean (±standard deviation) age, diabetes duration and blood sugar at admission were 44.06 (±16.23) years, 7.19 (±6.04) years and 26.37 (±6.70) mmol/L, respectively. Females comprised 51.4% of the study population. The most common presenting symptoms were generalised weakness (30.0%) and fever (14.3%). The major precipitants were infection (70.0%) and non-compliance (22.9%). Overall, 71.4% of participants had features suggestive of severe DKA. In a multivariable regression model, Type 2 diabetes was associated with over fourfold decreased odds of severe DKA (OR 0.23, 95% CI [0.07-0.76], p = 0.016). Patient education on prevention of DKA was documented for only 18.6% of patients before being discharged.

CONCLUSION

In this study, more than 70% of the study participants had features suggestive of severe DKA, with infection being the most common precipitant of DKA. 51.4% of patients had Type 2 diabetes which was associated with a statistically lower risk of severe DKA. Female sex tended to be positively associated with DKA severity. In a setting where the venous/arterial pH and bicarbonate levels may be inaccessible and/or unaffordable, using clinical features as found in the JBDS guidelines may help categorise patients and escalate care when needed. Indeed it may be useful to validate the use of the JBDS criteria for use in such settings.

Regulation of the renin-angiotensin-aldosterone system by cyclic nucleotides and phosphodiesterases

The renin-angiotensin-aldosterone system (RAAS) is one of the key players in the regulation of blood volume and blood pressure. Dysfunction of this system is connected with cardiovascular and renal diseases. Regulation of RAAS is under the control of multiple intracellular mechanisms. Cyclic nucleotides and phosphodiesterases are the major regulators of this system since they control expression and activity of renin and aldosterone. In this review, we summarize known mechanisms by which cyclic nucleotides and phosphodiesterases regulate renin gene expression, secretion of renin granules from juxtaglomerular cells and aldosterone production from zona glomerulosa cells of adrenal gland. We also discuss several open questions which deserve future attention.

Detection of two SNPs of the LIPE gene in Holstein-Friesian cows with divergent milk production

The LIPE gene (lipase E, hormone-sensitive type), also known as hormone-sensitive lipase, acts as a primary regulator of lipid metabolism during lactation in cows. We studied a total of two hundred Holstein-Friesian cows and performed sequencing analysis that revealed two synonymous nucleotide changes within the LIPE gene: a transition change, c.276 T > C in exon 2 (g.50631651 T > C; position 351 of GenBank: ON638900) and a transversion change, c.219C > A in exon 6 (g.50635369C > A; position 1070 of GenBank: ON638901). The observed genotypes were TC and CC for the c.276 T > C SNP and CC and CA for the c.219C > A SNP. Notably, the heterozygous TC genotype of the T351C SNP exhibited a significant association with high milk yield. Furthermore, the T351C SNP displayed significant associations with various milk parameters, including temperature, freezing point, density and the percentages of fat, protein, lactose, solids and solids-not-fat, with the homozygous CC genotype showing higher values. The c.219C > A SNP also demonstrated a significant association with milk composition, with heterozygous genotypes (CA) exhibiting higher percentages of fat, protein, and lactose compared to homozygous genotypes (CC). This effect was consistent among both high and low milk producers for fat and lactose percentages, while high milk producers exhibited a higher protein percentage than low milk producers. These findings highlight the importance of considering the detected SNPs in marker-assisted selection and breeding programs for the identification of high milk-producing Holstein-Friesian cows and potentially other breeds. Moreover, this study strongly supports the fundamental role of the LIPE gene in milk production and composition in lactating animals.

Differential expression of lipid metabolic genes in hypercholesterolemic rabbit placenta predisposes the offspring to develop atherosclerosis in early adulthood

AIMS

Maternal hypercholesterolemia (MHC) is a pathological condition that may cause atherosclerosis in the adulthood of the offspring. The study aims to identify the role of in-utero programming by the placenta in atherogenesis and associated liver pathology in offspring.

MAIN METHODS

Female New Zealand white rabbits with normal lipid profiles were fed a 0.3 % HFD after mating. Lipid levels were monitored, and pregnant rabbits were sacrificed at the end of trimester 1, trimester 2, and trimester 3. Placental histology and expression of lipid metabolism genes were studied. Lipid levels, aortic lesions, and mRNA expression of cholesterol synthesis genes were investigated in fetuses at the end of gestation. A group of fetuses was allowed to attain early adulthood to investigate the liver lipid metabolism and atherogenesis with and without an HFD.

KEY FINDINGS

Elevated maternal lipid levels and placental gene expression were differentially modulated in HFD-fed mothers. HFD-fed rabbits demonstrated differential expression of the placental genes involved in receptor-mediated endocytosis of cholesterol, lipogenesis, and lipolysis in all three trimesters. It resulted in significant lipid depositions in the placenta, hyperlipidemia, and a decrease in hepatic cholesterol synthesis in fetuses at the end of gestation. There was no atherogenesis in the aorta of offspring at trimester 3, but such offspring of HFD-fed mothers developed atherosclerosis and non-alcoholic fatty liver (NAFL) with profound steatosis in their early adulthood with and without HFD.

SIGNIFICANCE

Diet-induced MHC differentially expressed placental lipid genes that may program the offspring to develop atherosclerosis and associated NAFL in early adulthood.

Forward genetic screening using fundus spot scale identifies an essential role for Lipe in murine retinal homeostasis

Microglia play a role in the pathogenesis of many retinal diseases. Fundus spots in mice often correlate with the accumulation of activated subretinal microglia. Here we use a semiquantitative fundus spot scoring scale in combination with an unbiased, state-of-the-science forward genetics pipeline to identify causative associations between chemically induced mutations and fundus spot phenotypes. Among several associations, we focus on a missense mutation in Lipe linked to an increase in yellow fundus spots in C57BL/6J mice. Lipe^-/- mice generated using CRISPR-Cas9 technology are found to develop accumulation of subretinal microglia, a retinal degeneration with decreased visual function, and an abnormal retinal lipid profile. We establish an indispensable role of Lipe in retinal/RPE lipid homeostasis and retinal health. Further studies using this new model will be aimed at determining how lipid dysregulation results in the activation of subretinal microglia and whether these microglia also play a role in the subsequent retinal degeneration.

Increased BAT Thermogenesis in Male Mouse Apolipoprotein A4 Transgenic Mice

Dietary lipids induce apolipoprotein A4 (APOA4) production and brown adipose tissue (BAT) thermogenesis. Administration of exogenous APOA4 elevates BAT thermogenesis in chow-fed mice, but not high-fat diet (HFD)-fed mice. Chronic feeding of HFD attenuates plasma APOA4 production and BAT thermogenesis in wildtype (WT) mice. In light of these observations, we sought to determine whether steady production of APOA4 could keep BAT thermogenesis elevated, even in the presence of HFD consumption, with an aim toward eventual reduction of body weight, fat mass and plasma lipid levels. Transgenic mice with overexpression of mouse APOA4 in the small intestine (APOA4-Tg mice) produce greater plasma APOA4 than their WT controls, even when fed an atherogenic diet. Thus, we used these mice to investigate the correlation of levels of APOA4 and BAT thermogenesis during HFD consumption. The hypothesis of this study was that overexpression of mouse APOA4 in the small intestine and increased plasma APOA4 production would increase BAT thermogenesis and consequently reduce fat mass and plasma lipids of HFD-fed obese mice. To test this hypothesis, BAT thermogenic proteins, body weight, fat mass, caloric intake, and plasma lipids in male APOA4-Tg mice and WT mice fed either a chow diet or a HFD were measured. When fed a chow diet, APOA4 levels were elevated, plasma triglyceride (TG) levels were reduced, and BAT levels of UCP1 trended upward, while body weight, fat mass, caloric intake, and plasma lipids were comparable between APOA4-Tg and WT mice. After a four-week feeding of HFD, APOA4-Tg mice maintained elevated plasma APOA4 and reduced plasma TG, but UCP1 levels in BAT were significantly elevated in comparison to WT controls; body weight, fat mass and caloric intake were still comparable. After 10-week consumption of HFD, however, while APOA4-Tg mice still exhibited increased plasma APOA4, UCP1 levels and reduced TG levels, a reduction in body weight, fat mass and levels of plasma lipids and leptin were finally observed in comparison to their WT controls and independent of caloric intake. Additionally, APOA4-Tg mice exhibited increased energy expenditure at several time points when measured during the 10-week HFD feeding. Thus, overexpression of APOA4 in the small intestine and maintenance of elevated levels of plasma APOA4 appear to correlate with elevation of UCP1-dependent BAT thermogenesis and subsequent protection against HFD-induced obesity in mice.

Comparative Analyses Reveal the Genetic Mechanism of Ambergris Production in the Sperm Whale Based on the Chromosome-Level Genome

Sperm whales are a marine mammal famous for the aromatic substance, the ambergris, produced from its colon. Little is known about the biological processes of ambergris production, and this study aims to investigate the genetic mechanism of ambergris production in the sperm whale based on its chromosome-level genome. Comparative genomics analyses found 1207 expanded gene families and 321 positive selected genes (PSGs) in the sperm whale, and functional enrichment analyses suggested revelatory pathways and terms related to the metabolism of steroids, terpenoids, and aldosterone, as well as microbiota interaction and immune network in the intestine. Furthermore, two sperm-whale-specific missense mutations (Tyr393His and Leu567Val) were detected in the PSG LIPE, which has been reported to play vital roles in lipid and cholesterol metabolism. In total, 46 CYP genes and 22 HSD genes were annotated, and then mapped to sperm whale chromosomes. Furthermore, phylogenetic analysis of CYP genes in six mammals found that CYP2E1, CYP51A and CYP8 subfamilies exhibited relative expansion in the sperm whale. Our results could help understand the genetic mechanism of ambergris production, and further reveal the convergent evolution pattern among animals that produce similar odorants.

An Overview of Hormone-Sensitive Lipase (HSL)

Hormone-sensitive lipase (HSL) is a pivotal enzyme that mediates triglyceride hydrolysis to provide free fatty acids and glycerol in adipocytes in a hormonally controlled lipolysis process. Elevated plasma-free fatty acids were accompanied by insulin resistance, type-2 diabetes, and obesity. Inhibition of lipolysis through HSL inhibition may provide a mechanism to prevent the accumulation of free fatty acids and to improve the affectability of insulin and blood glucose handling in type II diabetes. The published studies that examine the structure, regulation, and function of HSL and major inhibitors were reviewed in this paper.

Role of lncRNA LIPE-AS1 in adipogenesis

Recent studies have identified long non-coding RNAs (lncRNAs) as potential regulators of adipogenesis. In this study, we have characterized a lncRNA, LIPE-AS1, that spans genes CEACAM1 to LIPE in man with conservation of genomic organization and tissue expression between mouse and man. Tissue-specific expression of isoforms of the murine lncRNA were found in liver and adipose tissue, one of which, designated mLas-V3, overlapped the Lipe gene encoding hormone-sensitive lipase in both mouse and man suggesting that it may have a functional role in adipose tissue. Knock down of expression of mLas-V3 using anti-sense oligos (ASOs) led to a significant decrease in the differentiation of the OP9 pre-adipocyte cell line through the down regulation of the major adipogenic transcription factors Pparg and Cebpa. Knock down of mLas-V3 induced apoptosis during the differentiation of OP9 cells as shown by expression of active caspase-3, a change in the localization of LIP/LAP isoforms of C/EBPβ, and expression of the cellular stress induced factors CHOP, p53, PUMA, and NOXA. We conclude that mLas-V3 may play a role in protecting against stress associated with adipogenesis, and its absence leads to apoptosis.

Loss of RUBCN/rubicon in adipocytes mediates the upregulation of autophagy to promote the fasting response

Upon fasting, adipocytes release their lipids that accumulate in the liver, thus promoting hepatic steatosis and ketone body production. However, the mechanisms underlying this process are not fully understood. In this study, we found that fasting caused a substantial decrease in the adipose levels of RUBCN/rubicon, a negative regulator of macroautophagy/autophagy, along with an increase in autophagy. Adipose-specific rubcn-knockout mice exhibited systemic fat loss that was not accelerated by fasting. Genetic inhibition of autophagy in adipocytes in fasted mice led to a reduction in fat loss, hepatic steatosis, and ketonemia. In terms of mechanism, autophagy decreased the levels of its substrates NCOA1/SRC-1 and NCOA2/TIF2, which are also coactivators of PPARG/PPARγ, leading to a fasting-induced reduction in the mRNA levels of adipogenic genes in adipocytes. Furthermore, RUBCN in adipocytes was degraded through the autophagy pathway, suggesting that autophagic degradation of RUBCN serves as a feedforward system for autophagy induction during fasting. Collectively, we propose that loss of adipose RUBCN promotes a metabolic response to fasting via increasing autophagic activity.

Response of circulating metabolites to an oral glucose challenge and risk of cardiovascular disease and mortality in the community

Background

New biomarkers to identify cardiovascular disease (CVD) risk earlier in its course are needed to enable targeted approaches for primordial prevention. We evaluated whether intraindividual changes in blood metabolites in response to an oral glucose tolerance test (OGTT) may provide incremental information regarding the risk of future CVD and mortality in the community.

Methods

An OGTT (75 g glucose) was administered to a subsample of Framingham Heart Study participants free from diabetes (n = 361). Profiling of 211 plasma metabolites was performed from blood samples drawn before and 2 h after OGTT. The log2(post/pre) metabolite levels (Δmetabolites) were related to incident CVD and mortality in Cox regression models adjusted for age, sex, baseline metabolite level, systolic blood pressure, hypertension treatment, body mass index, smoking, and total/high-density lipoprotein cholesterol. Select metabolites were related to subclinical cardiometabolic phenotypes using Spearman correlations adjusted for age, sex, and fasting metabolite level.

Results

Our sample included 42% women, with a mean age of 56 ± 9 years and a body mass index of 30.2 ± 5.3 kg/m². The pre- to post-OGTT changes (Δmetabolite) were non-zero for 168 metabolites (at FDR ≤ 5%). A total of 132 CVD events and 144 deaths occurred during median follow-up of 24.9 years. In Cox models adjusted for clinical risk factors, four Δmetabolites were associated with incident CVD (higher glutamate and deoxycholate, lower inosine and lysophosphatidylcholine 18:2) and six Δmetabolites (higher hydroxyphenylacetate, triacylglycerol 56:5, alpha-ketogluturate, and lower phosphatidylcholine 32:0, glucuronate, N-monomethyl-arginine) were associated with death (P < 0.05). Notably, baseline metabolite levels were not associated with either outcome in models excluding Δmetabolites. The Δmetabolites exhibited varying cross-sectional correlation with subclinical risk factors such as visceral adiposity, insulin resistance, and vascular stiffness, but overall relations were modest. Significant Δmetabolites included those with established roles in cardiometabolic disease (e.g., glutamate, alpha-ketoglutarate) and metabolites with less defined roles (e.g., glucuronate, lipid species).

Conclusions

Dynamic changes in metabolite levels with an OGTT are associated with incident CVD and mortality and have potential relevance for identifying CVD risk earlier in its development and for discovering new potential therapeutic targets.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-022-01647-w.

An overview of mammalian and microbial hormone-sensitive lipases (lipolytic family IV): biochemical properties and industrial applications

In mammals, hormone-sensitive lipase (EC 3.1.1.79) is an intracellular lipase that significantly regulates lipid metabolism. Mammalian HSL is more active towards diacylglycerol but lacks a lid covering the active site. Dyslipidemia, hepatic steatosis, cancer, and cancer-associated cachexia are symptoms of HSL pathophysiology. Certain microbial proteins show a sequence homologous to the catalytic domain of mammalian HSL, hence called microbial HSL. They possess a funnel-shaped substrate-binding pocket and restricted length of acyl chain esters, thus known as esterases. These enzymes have broad substrate specificities and are capable of stereo, regio, and enantioselective, making them attractive biocatalysts in a wide range of industrial applications in the production of flavors, pharmaceuticals, biosensors, and fine chemicals. This review will provide insight into mammalian and microbial HSLs, their sources, structural features related to substrate specificity, thermal stability, and their applications.

Serine Hydrolases in Lipid Homeostasis of the Placenta-Targets for Placental Function?

The metabolic state of pregnant women and their unborn children changes throughout pregnancy and adapts to the specific needs of each gestational week. These adaptions are accomplished by the actions of enzymes, which regulate the occurrence of their endogenous substrates and products in all three compartments: mother, placenta and the unborn. These enzymes determine bioactive lipid signaling, supply, and storage through the generation or degradation of lipids and fatty acids, respectively. This review focuses on the role of lipid-metabolizing serine hydrolases during normal pregnancy and in pregnancy-associated pathologies, such as preeclampsia, gestational diabetes mellitus, or preterm birth. The biochemical properties of each class of lipid hydrolases are presented, with special emphasis on their role in placental function or dysfunction. While, during a normal pregnancy, an appropriate tonus of bioactive lipids prevails, dysregulation and aberrant signaling occur in diseased states. A better understanding of the dynamics of serine hydrolases across gestation and their involvement in placental lipid homeostasis under physiological and pathophysiological conditions will help to identify new targets for placental function in the future.

A global lipid map reveals host dependency factors conserved across SARS-CoV-2 variants

A comprehensive understanding of host dependency factors for SARS-CoV-2 remains elusive. Here, we map alterations in host lipids following SARS-CoV-2 infection using nontargeted lipidomics. We find that SARS-CoV-2 rewires host lipid metabolism, significantly altering hundreds of lipid species to effectively establish infection. We correlate these changes with viral protein activity by transfecting human cells with each viral protein and performing lipidomics. We find that lipid droplet plasticity is a key feature of infection and that viral propagation can be blocked by small-molecule glycerolipid biosynthesis inhibitors. We find that this inhibition was effective against the main variants of concern (alpha, beta, gamma, and delta), indicating that glycerolipid biosynthesis is a conserved host dependency factor that supports this evolving virus.

KIAA1363-A Multifunctional Enzyme in Xenobiotic Detoxification and Lipid Ester Hydrolysis

KIAA1363, annotated as neutral cholesterol ester hydrolase 1 (NCEH1), is a member of the arylacetamide deacetylase (AADAC) protein family. The name-giving enzyme, AADAC, is known to hydrolyze amide and ester bonds of a number of xenobiotic substances, as well as clinical drugs and of endogenous lipid substrates such as diglycerides, respectively. Similarly, KIAA1363, annotated as the first AADAC-like protein, exhibits enzymatic activities for a diverse substrate range including the xenobiotic insecticide chlorpyrifos oxon and endogenous substrates, acetyl monoalkylglycerol ether, cholesterol ester, and retinyl ester. Two independent knockout mouse models have been generated and characterized. However, apart from reduced acetyl monoalkylglycerol ether and cholesterol ester hydrolase activity in specific tissues and cell types, no gross-phenotype has been reported. This raises the question of its physiological role and whether it functions as drug detoxifying enzyme and/or as hydrolase/lipase of endogenous substrates. This review delineates the current knowledge about the structure, function and of the physiological role of KIAA1363, as evident from the phenotypical changes inflicted by pharmacological inhibition or by silencing as well as knockout of KIAA1363 gene expression in cells, as well as mouse models, respectively.

Cholecystokinin promotes functional expression of the aquaglycerol channel aquaporin 7 in adipocytes

BACKGROUND AND PURPOSE

Cholecystokinin (CCK) promotes triglyceride storage and adiponectin production in white adipose tissue (WAT), suggesting that CCK modulates WAT homeostasis. Our goal was to investigate the role of CCK in regulating the expression and function of the aquaglycerol channel aquaporin 7 (AQP7), a protein that is pivotal for maintaining adipocyte homeostasis and preserving insulin responsiveness.

EXPERIMENTAL APPROACH

The effect of the bioactive fragment of CCK, CCK-8, in regulating adipose AQP7 expression and glycerol efflux was assessed in rats as well as in pre-adipocytes. Moreover, the involvement of insulin receptors in the effects of CCK-8 was characterized in pre-adipocytes lacking insulin receptors.

KEY RESULTS

CCK-8 induced AQP7 gene expression in rat WAT, concomitantly increasing plasma glycerol concentration. In isolated pre-adipocytes, CCK-8 also enhanced both AQP7 expression and glycerol leakage. The effect of CCK-8 was independent of the lipolysis rate, as CCK-8 failed to promote fatty acid release by adipocytes. In addition, CCK-8 did not enhance hormone sensitive lipase phosphorylation, which is the rate-limiting step of lipolysis. Moreover, the effects of CCK-8 were dependent on the activation of protein kinase B and PPARγ. Silencing insulin receptor (IR) expression inhibited CCK-8-induced Aqp7 expression in pre-adipocytes. Furthermore, insulin enhanceded the effect of CCK-8.

CONCLUSIONS AND IMPLICATIONS

CCK regulates AQP7 expression and function, and this effect is dependent on insulin. Accordingly, CCK receptor agonists could be suitable for preserving and improving insulin responsiveness in WAT.

Roles of vimentin in health and disease

More than 27 yr ago, the vimentin knockout (Vim-/- ) mouse was reported to develop and reproduce without an obvious phenotype, implying that this major cytoskeletal protein was nonessential. Subsequently, comprehensive and careful analyses have revealed numerous phenotypes in Vim-/- mice and their organs, tissues, and cells, frequently reflecting altered responses in the recovery of tissues following various insults or injuries. These findings have been supported by cell-based experiments demonstrating that vimentin intermediate filaments (IFs) play a critical role in regulating cell mechanics and are required to coordinate mechanosensing, transduction, signaling pathways, motility, and inflammatory responses. This review highlights the essential functions of vimentin IFs revealed from studies of Vim-/- mice and cells derived from them.

Hereditary severe insulin resistance syndrome: Pathogenesis, pathophysiology, and clinical management

Severe insulin resistance has been linked to some of the most globally prevalent disorders, such as diabetes mellitus, nonalcoholic fatty liver disease, polycystic ovarian syndrome, and hypertension. Hereditary severe insulin resistance syndrome (H-SIRS) is a rare disorder classified into four principal categories: primary insulin receptor defects, lipodystrophies, complex syndromes, and obesity-related H-SIRS. Genes such as INSR, AKT2, TBC1D4, AGPAT2, BSCL2, CAV1, PTRF, LMNA, PPARG, PLIN1, CIDEC, LIPE, PCYT1A, MC4R, LEP, POMC, SH2B1, RECQL2, RECQL3, ALMS1, PCNT, ZMPSTE24, PIK3R1, and POLD1 have been linked to H-SIRS. Its clinical features include insulin resistance, hyperglycemia, hyperandrogenism, severe dyslipidemia, fatty liver, abnormal topography of adipose tissue, and low serum leptin and adiponectin levels. Diagnosis of H-SIRS is based on the presence of typical clinical features associated with the various H-SIRS forms and the identification of mutations in H-SIRS-linked genes by genetic testing. Diet therapy, insulin sensitization, exogenous insulin therapy, and leptin replacement therapy have widely been adopted to manage H-SIRS. The rarity of H-SIRS, its highly variable clinical presentation, refusal to be tested for genetic mutations by patients' family members who are not severely sick, unavailability of genetic testing, and testing expenses contribute to the delayed or underdiagnoses of H-SIRS. Early diagnosis facilitates early management of the condition, which results in improved glycemic control and delayed onset of diabetes and other complications related to severe insulin resistance. The use of updated genetic sequencing technologies is recommended, and long-term studies are required for genotype-phenotype differentiation and formulation of diagnostic and treatment protocols.

Hormone-sensitive lipase is localized at synapses and is necessary for normal memory functioning in mice

Hormone-sensitive lipase (HSL) is mainly present in adipose tissue where it hydrolyses diacylglycerol. Although expression of HSL has also been reported in the brain, its presence in different cellular compartments is uncertain, and its role in regulating brain lipid metabolism remains hitherto unexplored. We hypothesized HSL might play a role in regulating the availability of bioactive lipids necessary for neuronal function, and therefore investigated whether dampening HSL activity could lead to brain dysfunction. In mice, we found HSL protein and enzymatic activity throughout the brain, both localized within neurons and enriched in synapses. HSL-null mice were then analyzed using a battery of behavioral tests. Relative to wild-type littermates, HSL-null mice showed impaired short- and long-term memory, yet preserved exploratory behaviurs. Molecular analysis of the cortex and hippocampus showed increased expression of genes involved in glucose utilization in the hippocampus, but not cortex, of HSL-null mice compared to controls. Furthermore, lipidomics analyses indicated an impact of HSL deletion on the profile of bioactive lipids, including a decrease in endocannabinoids and eicosanoids that are known to modulate neuronal activity, cerebral blood flow, and inflammation processes. Accordingly, mild increases in the expression of pro-inflammatory cytokines in HSL mice compared to littermates were suggestive of low-grade inflammation. We conclude that HSL has a homeostatic role in maintaining pools of lipids required for normal brain function. It remains to be tested, however, whether the recruitment of HSL for the synthesis of these lipids occurs during increased neuronal activity, or whether HSL participates in neuroinflammatory responses.

Effects and Mechanism of Different Phospholipid Diets on Ovary Development in Female Broodstock Pacific White Shrimp, Litopenaeus vannamei

Research on nutrition and feed development for the broodstock of the Pacific white shrimp, Litopenaeus vannamei, is rare, and a poor broodstock quality is a critical factor restricting the seed supply in shrimp farming. As an essential nutrient for the gonadal development of L. vannamei, one control diet (no phospholipid) and three typical phospholipids (soybean lecithin, egg yolk lecithin, and krill oil) were evaluated in a semipurified diet of 4% phospholipid for a 28-day trial (initial weight 34.7 ± 4.2 g). Dietary phospholipid supplementation significantly promoted the ovarian maturation of female L. vannamei. Compared with soybean lecithin and egg yolk lecithin, krill oil showed the best positive results. Shrimp fed with a diet krill oil has obtained a significantly higher gonadosomatic index, yolk particle deposition, lipid accumulation, and estrogen secretion than from other sources. Ovary lipidomic analysis showed that the krill oil enriched the lipid composition of the ovary. The “glycerophospholipid metabolism” and “sphingolipid metabolism” pathways were significantly varied via topological pathway analysis. Genes and hub genes, with significantly different expression levels, were significantly enriched in the “fatty acid metabolism pathway,” “glycerophospholipid metabolism,” and “arachidonic acid metabolism” pathways by transcriptomic analysis. Correlation analysis of the transcriptome and lipidomics showed that the differential gene “hormone-sensitive lipase-like” (HSL) was positively correlated with various lipids [triglycerides (TG), phosphatidic acid (PA), phosphatidylserine (P), phosphatidylethanolamine (PE), glucosylceramide (GlcCer), phosphatidylglycerol (PG), and phosphatidylinositol (PI)] but was negatively correlated with diacylglycerol (DG), lysophosphatidylethanolamine (LPE), and sphingomyelin (SM). In conclusion, the dietary phospholipids, especially krill oil as a phospholipid source, can promote the development of L. vannamei ovaries by increasing the accumulation of nutrients such as triglycerides and sterols, and the secretion of estrogen or related hormones, such as estradiol and methylfarneside, by affecting the metabolism of glycerol phospholipids and some key fatty acids.

Effect of high altitude on human postprandial 13 C-octanoate metabolism, intermediary metabolites, gastrointestinal peptides, and visceral perception

OBJECTIVE

At high altitude (HA), acute mountain sickness (AMS) is accompanied by neurologic and upper gastrointestinal symptoms (UGS). The primary aim of this study was to test the hypothesis that delayed gastric emptying (GE), assessed by ¹³ C-octanoate breath testing (OBT), causes UGS in AMS. The secondary aim was to assess post-gastric mechanisms of OBT, which could confound results under these conditions, by determination of intermediary metabolites, gastrointestinal peptides, and basal metabolic rate.

METHODS

A prospective trial was performed in 25 healthy participants (15 male) at 4559 m (HA) and at 490 m (Zurich). GE was assessed by OBT (428 kcal solid meal) and UGS by visual analogue scales (VAS). Blood sampling of metabolites (glucose, free fatty acids (FFA), triglycerides (TG), beta-hydroxyl butyrate (BHB), L-lactate) and gastrointestinal peptides (insulin, amylin, PYY, etc.) was performed as well as blood gas analysis and spirometry.

STATISTICAL ANALYSIS

variance analyses, bivariate correlation, and multilinear regression analysis.

RESULTS

After 24 h under hypoxic conditions at HA, participants developed AMS (p < 0.001). ¹³ CO₂ exhalation kinetics increased (p < 0.05) resulting in reduced estimates of gastric half-emptying times (p < 0.01). However, median resting respiratory quotients and plasma profiles of TG indicated that augmented beta-oxidation was the main predictor of accelerated ¹³ CO₂ -generation under these conditions.

CONCLUSION

Quantification of ¹³ C-octanoate oxidation by a breath test is sensitive to variation in metabolic (liver) function under hypoxic conditions. ¹³ C-breath testing using short-chain fatty acids is not reliable for measurement of gastric function at HA and should be considered critically in other severe hypoxic conditions, like sepsis or chronic lung disease.

A global lipid map reveals host dependency factors conserved across SARS-CoV-2 variants

A comprehensive understanding of host dependency factors for SARS-CoV-2 remains elusive. We mapped alterations in host lipids following SARS-CoV-2 infection using nontargeted lipidomics. We found that SARS-CoV-2 rewires host lipid metabolism, altering 409 lipid species up to 64-fold relative to controls. We correlated these changes with viral protein activity by transfecting human cells with each viral protein and performing lipidomics. We found that lipid droplet plasticity is a key feature of infection and that viral propagation can be blocked by small-molecule glycerolipid biosynthesis inhibitors. We found that this inhibition was effective against the main variants of concern (alpha, beta, gamma, and delta), indicating that glycerolipid biosynthesis is a conserved host dependency factor that supports this evolving virus.

Morphological and Immunophenotypical Changes of Human Bone Marrow Adipocytes in Marrow Metastasis and Myelofibrosis

The bone marrow adipose tissue constitutes more than two-thirds of the bone marrow volume in adult life and is known to have unique metabolic and functional properties. In neoplastic disorders, bone marrow adipocytes (BMAds) contribute to create a favorable microenvironment to survival and proliferation of cancer cells. Many studies explored the molecular crosstalk between BMAds and neoplastic cells, predominantly in ex-vivo experimental systems or in animal models. However, little is known on the features of BMAds in the human neoplastic marrow. The aim of our study was to analyze the in situ changes in morphology and immunophenotype of BMAds in two different types of neoplastic marrow conditions. We selected a series of archival iliac crest and vertebral bone biopsies from patients with bone marrow metastasis (MET), patients with myeloproliferative neoplasia with grade-3 myelofibrosis (MPN-MF) and age-matched controls (CTR). We observed a significant reduction in the number of BMAds in MET and MPN-MF compared to CTR. Accordingly, in the same groups, we also detected a significant reduction in the mean cell diameter and area. Immunolocalization of different adipocyte markers showed that, compared to CTR, in both MET and MPN-MF the percentages of adiponectin- and phosphorylated hormone sensitive lipase-positive BMAds were significantly reduced and increased respectively. No statistically significant difference was found between MET and MPN-MF. Interestingly, in one MET sample, "remodeled" BMAds containing a large lipid vacuole and multiple, smaller and polarized lipid droplets were identified. In conclusion, our data show that in different types of marrow cancers, BMAds undergo significant quantitative and qualitative changes, which need to be further investigated in future studies.

Dietary copper supplementation enhances lipolysis in Rex rabbits

BACKGROUND

Copper is an important regulator of lipid metabolism in mammals, as a cofactor of many enzymes and is involved in the lipolysis. Copper deficiency has been considered as a significant factor in human diseases related to abnormal lipid metabolism, while adding copper to the diet seems to be the simplest and most effective way to prevent copper deficiency.

AIMS

The aim of this study was to investigate the effects of dietary copper level on lipid metabolism in Rex Rabbits.

METHODS

A total of 120 90-d-old Rex Rabbits were randomly allotted into three treatments, with 40 replicates (20 males, 20 females) in each treatment (1 rabbit per replicate). The diets included 1) control (8.4 mg/kg), normal-copper diet (39.1 mg/kg), 3) high-copper diet (67.5 mg/kg). The trial including a one-week adaptation period and a five-week experimental period.

RESULT

The results showed that copper (39.1 mg/kg) diet increased average daily feed intake (ADFI) (P＜0.05, N = 34), and tended to increase the final body weight (FBW) (P = 0.0556, N = 34). Moreover, dietary copper addition (39.1 and 67.5 mg/kg) significantly increased the foreleg and hindleg weight (P＜0.05, N = 8), and decreased the weight of Perirenal fat and the concentration of triglycerides (TG) in the liver (P＜0.05, N = 8). The concentration of triglycerides (TG), epinephrine (EPI), and glucagon (GC) in serum were obviously higher than that in control group (P＜0.05, N = 8), and the concentration of insulin (INS), and very low-density lipoprotein (VLDL) in serum were significantly decreased (P＜0.05, N = 8). The copper group (39.1 mg/kg) showed up-regulated gene expression levels of carnitine palmitoyl transferases (CPT-1 and CPT-2) and peroxisome proliferator-activated receptor (PPAR-α) in liver (P < 0.05, N = 8) and down-regulated gene expression levels of fatty acid synthase (FAS) and Acetyl-CoA carboxylase (ACC) (P < 0.05, N = 8). In skeletal muscle, CPT-1, CPT-2, PPAR-α, fatty acid transport protein (FATP), fatty acid-binding protein (FABP) and lipoprotein lipase (LPL) levels were significantly up-regulated by copper treatment (P < 0.05, N = 8). Rex Rabbits receiving copper addition had higher CPT-1, CPT-2, PPAR-a and hormone-sensitive lipase (HSL) mRNA levels in adipose tissue (P < 0.05, N = 8).

CONCLUSION

Copper diets promoted skeletal muscle growth and reduced fat accumulation by enhancing fatty acid oxidation, at the same time, dietary copper inhibited De novo lipogenesis in the liver. PPAR-α signaling in liver, skeletal muscle and adipose tissues were involved in the regulation of lipid metabolism by copper.

Hormone-sensitive lipase deficiency affects the expression of SR-BI, LDLr, and ABCA1 receptors/transporters involved in cellular cholesterol uptake and efflux and disturbs fertility in mouse testis

Hormone-sensitive lipase (HSL) hydrolyse acylglycerols, cholesteryl and retinyl esters. HSL is a key lipase in mice testis, as HSL deficiency results in male sterility. The present work study the effects of the deficiency and lack of HSL on the localization and expression of SR-BI, LDLr, and ABCA1 receptors/transporters involved in uptake and efflux of cholesterol in mice testis, to determine the impact of HSL gene dosage on testis morphology, lipid homeostasis and fertility. The results of this work show that the lack of HSL in mice alters testis morphology and spermatogenesis, decreasing sperm counts, sperm motility and increasing the amount of Leydig cells and lipid droplets. They also show that there are differences in the localization of HSL, SR-BI, LDLr and ABCA1 in HSL+/+, HSL+/- and HSL-/- mice. The deficiency or lack of HSL has effects on protein and mRNA expression of genes involved in lipid metabolisms in mouse testis. HSL-/- testis have augmented expression of SR-BI, LDLr, ABCA1 and LXRβ, a critical sterol sensor that regulate multiple genes involved in lipid metabolism; whereas LDLr expression decreased in HSL+/- mice. Plin2, Abca1 and Ldlr mRNA levels increased; and LXRα (Nr1h3) and LXRβ (Nr1h2) decreased in testis from HSL-/- compared with HSL+/+; with no differences in Scarb1. Together these data suggest that HSL deficiency or lack in mice testis induces lipid homeostasis alterations that affect the cellular localization and expression of key receptors/transporter involved in cellular cholesterol uptake and efflux (SR-BI, LDRr, ABCA1); alters normal cellular function and impact fertility.

CIDEA expression in SAT from adolescent girls with obesity and unfavorable patterns of abdominal fat distribution

OBJECTIVE

This study investigated whether variations in cell death-inducing DNA fragmentation factor alpha subunit-like effector A (CIDEA) mRNA expression and protein levels are modulated by the pattern of abdominal fat distribution in adolescent girls with obesity.

METHODS

This study recruited 35 adolescent girls with obesity and characterized their abdominal fat distribution by magnetic resonance imaging. Participants had only a periumbilical/abdominal (n = 14) or a paired abdominal and gluteal subcutaneous adipose tissue (SAT) biopsy (n = 21). CIDEA expression was determined by reverse transcription-polymerase chain reaction, CIDEA protein level by Western blot, and the turnover of adipose lipids and adipocytes by 2 H2 O labeling. In six girls, a second abdominal SAT biopsy was performed (after ~34.2 months) to explore the weight gain effect on CIDEA expression in abdominal SAT.

RESULTS

CIDEA expression decreased in abdominal SAT from participants with high visceral adipose tissue (VAT)/(VAT+SAT); CIDEA inversely correlated with number of small adipocytes, with the increase in preadipocyte proliferation, and with adipogenesis. A strong inverse correlation was found between CIDEA protein level with the newly synthetized glycerol (r = -0.839, p = 0.0047). Following weight gain, an increase in adipocytes' cell diameter with a decrease in CIDEA expression and RNA-sequencing transcriptomic profile typical of adipocyte dysfunction was observed.

CONCLUSIONS

Reduced expression of CIDEA in girls with high VAT/(VAT+SAT) is associated with adipocyte hypertrophy and insulin resistance.

Phthalates and Alternative Plasticizers Differentially affect Phenotypic Parameters in Gonadal Somatic and Germ Cell Lines

The developmental and reproductive toxicity associated with exposure to phthalates has motivated a search for alternatives. However, there is limited knowledge regarding the adverse effects of some of these chemicals. We used high-content imaging to compare the effects of mono (2-ethylhexyl) phthalate (MEHP) with six alternative plasticizers: di-2-ethylhexyl terephthalate (DEHTP); diisononyl-phthalate (DINP); di-isononylcyclohexane-1,2-dicarboxylate (DINCH); 2-ethylhexyl adipate (DEHA); 2,2,4-trimethyl 1,3-pentanediol diisobutyrate (TXIB) and di-iso-decyl-adipate (DIDA). A male germ spermatogonial cell line (C18-4), a Sertoli cell line (TM4) and two steroidogenic cell lines (MA-10 Leydig and KGN granulosa) were exposed for 48h to each chemical (0.001-100 μM). Cell images were analyzed to assess cytotoxicity and effects on phenotypic endpoints. Only MEHP (100 μM) was cytotoxic and only in C18-4 cells. However, several plasticizers had distinct phenotypic effects in all four cell lines. DINP increased Calcein intensity in C18-4 cells, whereas DIDA induced oxidative stress. In TM4 cells, MEHP, and DINCH affected lipid droplet numbers, while DEHTP and DINCH increased oxidative stress. In MA-10 cells, MEHP increased lipid droplet areas and oxidative stress; DINP decreased the number of lysosomes, while DINP, DEHA and DIDA altered mitochondrial activity. In KGN cells, MEHP, DINP and DINCH increased the number of lipid droplets, whereas DINP decreased the number of lysosomes, increased oxidative stress and affected mitochondria. The Toxicological Priority Index (ToxPi) provided a visual illustration of the cell line specificity of the effects on phenotypic parameters. The lowest administered equivalent doses were observed for MEHP. We propose that this approach may assist in screening alternative plasticizers.

Enzyme-Catalyzed Hydrolysis of Lipids in Immiscible Microdroplets Studied by Contained-Electrospray Ionization

Enzyme-catalyzed hydrolysis of lipids was monitored directly in immiscible microdroplet environments using contained-electrospray mass spectrometry. Aqueous solution of the lipase enzyme from Pseudomonas cepacia and the chloroform solution of the lipids were sprayed from separate capillaries, and the resultant droplets were merged within a reaction cavity that is included at the outlet of the contained-electrospray ionization source. By varying the length of the reaction cavity, the interaction time between the enzyme and its substrate was altered, enabling the quantification of reaction product as a function of time. Consequently, enhancement factors were estimated by comparing rate constants derived from the droplet experiment to rate constants calculated from solution-phase conditions. These experiments showed enhancement factors greater than 100 in favor of the droplet experiment. By using various lipid types, two possible mechanisms were identified to account for lipase reactivity in aerosols: in-droplet reactions for relatively highly soluble lipids and a droplet coalescence mechanism that allows interfacial reactions for the two immiscible systems.

Luteinizing Hormone Regulation of Inter-Organelle Communication and Fate of the Corpus Luteum

The corpus luteum is an endocrine gland that synthesizes the steroid hormone progesterone. luteinizing hormone (LH) is a key luteotropic hormone that stimulates ovulation, luteal development, progesterone biosynthesis, and maintenance of the corpus luteum. Luteotropic and luteolytic factors precisely regulate luteal structure and function; yet, despite recent scientific progress within the past few years, the exact mechanisms remain largely unknown. In the present review, we summarize the recent progress towards understanding cellular changes induced by LH in steroidogenic luteal cells. Herein, we will focus on the effects of LH on inter-organelle communication and steroid biosynthesis, and how LH regulates key protein kinases (i.e., AMPK and MTOR) responsible for controlling steroidogenesis and autophagy in luteal cells.

Characterization of a novel carboxylesterase with catalytic activity toward di(2-ethylhexyl) phthalate from a soil metagenomic library

A novel carboxylesterase gene estyz5 was isolated from a soil metagenomic library. The recombinant enzyme EstYZ5 is 298 amino acids in length with a predicted molecular weight of 32 kDa. Sequence alignment and phylogenetic analysis revealed that EstYZ5 belongs to the hormone-sensitive lipase (HSL) family with a deduced catalytic triad of Ser144-Glu238-His268. EstYZ5 contains two conserved motifs, a pentapeptide motif GDSAG and a HGGG motif, which are typically found in members of the HSL family. Esterolytic activity of the recombinant enzyme was optimal at 30 °C and pH 8.0, and the kcat/Km value of the enzyme for the optimum substrate p-nitrophenyl butyrate was as high as 1272 mM^-1·s^-1. Importantly, EstYZ5 showed activity toward di(2-ethylhexyl) phthalate with complex side chains, which is rare for HSLs. Molecular docking simulations revealed that the catalytic triad and an oxyanion hole likely play vital roles in enzymatic activity and specificity. The phthalate-degrading activity of EstYZ5, combined with its high levels of esterolytic activity, render this new enzyme a candidate for biotechnological applications.

The Mechanism of Secretion and Metabolism of Gut-Derived 5-Hydroxytryptamine

Serotonin, also known as 5-hydroxytryptamine (5-HT), is a metabolite of tryptophan and is reported to modulate the development and neurogenesis of the enteric nervous system, gut motility, secretion, inflammation, sensation, and epithelial development. Approximately 95% of 5-HT in the body is synthesized and secreted by enterochromaffin (EC) cells, the most common type of neuroendocrine cells in the gastrointestinal (GI) tract, through sensing signals from the intestinal lumen and the circulatory system. Gut microbiota, nutrients, and hormones are the main factors that play a vital role in regulating 5-HT secretion by EC cells. Apart from being an important neurotransmitter and a paracrine signaling molecule in the gut, gut-derived 5-HT was also shown to exert other biological functions (in autism and depression) far beyond the gut. Moreover, studies conducted on the regulation of 5-HT in the immune system demonstrated that 5-HT exerts anti-inflammatory and proinflammatory effects on the gut by binding to different receptors under intestinal inflammatory conditions. Understanding the regulatory mechanisms through which 5-HT participates in cell metabolism and physiology can provide potential therapeutic strategies for treating intestinal diseases. Herein, we review recent evidence to recapitulate the mechanisms of synthesis, secretion, regulation, and biofunction of 5-HT to improve the nutrition and health of humans.

Effects of Totum-63 on glucose homeostasis and postprandial glycemia: a translational study

Global prevalence of type 2 diabetes (T2D) is rising and may affect 700 million people by 2045. Totum-63 is a polyphenol-rich natural composition developed to reduce the risk of T2D. We first investigated the effects of Totum-63 supplementation in high-fat diet (HFD)-fed mice for up to 16 wk and thereafter assessed its safety and efficacy (2.5 g or 5 g per day) in 14 overweight men [mean age 51.5 yr, body mass index (BMI) 27.6 kg·m^-2] for 4 wk. In HFD-fed mice, Totum-63 reduced body weight and fat mass gain, whereas lean mass was unchanged. Moreover, fecal energy excretion was higher in Totum-63-supplemented mice, suggesting a reduction of calorie absorption in the digestive tract. In the gut, metagenomic analyses of fecal microbiota revealed a partial restoration of HFD-induced microbial imbalance, as shown by principal coordinate analysis of microbiota composition. HFD-induced increase in HOMA-IR score was delayed in supplemented mice, and insulin response to an oral glucose tolerance test was significantly reduced, suggesting that Totum-63 may prevent HFD-related impairments in glucose homeostasis. Interestingly, these improvements could be linked to restored insulin signaling in subcutaneous adipose tissue and soleus muscle. In the liver, HFD-induced steatosis was reduced by 40% (as shown by triglyceride content). In the subsequent study in men, Totum-63 (5 g·day^-1) improved glucose and insulin responses to a high-carbohydrate breakfast test (84% kcal carbohydrates). It was well tolerated, with no clinically significant adverse events reported. Collectively, these data suggest that Totum-63 could improve glucose homeostasis in both HFD-fed mice and overweight individuals, presumably through a multitargeted action on different metabolic organs.NEW & NOTEWORTHY Totum-63 is a novel polyphenol-rich natural composition developed to reduce the risk of T2D. Totum-63 showed beneficial effects on glucose homeostasis in HFD-fed mice, presumably through a multitargeted action on different metabolic organs. Totum-63 was well tolerated in humans and improved postprandial glucose and insulin responses to a high-carbohydrate breakfast test.

Alisol A 24-acetate stimulates lipolysis in 3 T3-L1 adipocytes

BACKGROUND

Alisol A 24-acetate (AA-24-a), one of the main active triterpenes isolated from the well-known medicinal plant Alisma orientale (Sam.) Juz., exhibits multiple biological activities including hypolipidemic activity. However, its effect on lipid metabolism in adipocytes remains unclear. The present study aimed to clarify the effect of AA-24-a on adipocyte lipolysis and to determine its potential mechanism of action using 3 T3-L1 cells.

METHODS

We assayed the release of glycerol into culture medium of 3 T3-L1 cells under treatment with AA-24-a. Protein and mRNA expression and phosphorylation levels of the main lipases and kinases involved in lipolysis regulation were determined by quantitative polymerase chain reaction and western blotting. Specific inhibitors of protein kinase A (PKA; H89) and extracellular signal-regulated kinase (ERK; PD98059), which are key enzymes in relevant signaling pathways, were used to examine their roles in AA-24-a-stimulated lipolysis.

RESULTS

AA-24-a significantly stimulated neutral lipolysis in fully differentiated adipocytes. To determine the underlying mechanism, we assessed the changes in mRNA and protein levels of key lipolysis-related genes in the presence or absence of H89 and PD98059. Both inhibitors reduced AA-24-a-induced lipolysis. Moreover, pretreatment with H89 attenuated AA-24-a-induced phosphorylation of hormone-sensitive lipase at Ser660, while pretreatment with PD98059 attenuated AA-24-a-induced downregulation of peroxisome proliferator-activated receptor-γ and perilipin A.

CONCLUSIONS

Our results indicate that AA-24-a promoted neutral lipolysis in 3 T3-L1 adipocytes by activating PKA-mediated phosphorylation of hormone-sensitive lipase and ERK- mediated downregulation of expression of perilipin A.

Elucidation of the Effects of Bisphenol A and Structural Analogs on Germ and Steroidogenic Cells Using Single Cell High-Content Imaging

Concerns about the potential adverse effects of bisphenol A (BPA) have led to an increase in the use of replacements, yet the toxicity data for several of these chemicals are limited. Using high-content imaging, we compared the effects of BPA, BPAF, BPF, BPS, BPM, and BPTMC in germ (C18-4 spermatogonial) and steroidogenic (MA-10 Leydig and KGN granulosa) cell lines. Effects on cell viability and phenotypic markers were analyzed to determine benchmark concentrations (BMCs) and estimate administered equivalent doses (AEDs). In all 3 cell lines, BPA was one of the least cytotoxic bisphenol compounds tested, whereas BPM and BPTMC were the most cytotoxic. Interestingly, BPF and BPS were cytotoxic only in MA-10 cells. Effects on phenotypic parameters, including mitochondria, lysosomes, lipid droplets, and oxidative stress, were both bisphenol- and cell-line specific. BPA exposure affected mitochondria (BMC: 1.2 μM; AED: 0.09 mg/kg/day) in C18-4 cells. Lysosome numbers were increased in MA-10 cells exposed to BPA or BPAF but decreased in KGN cells exposed to BPAF or BPM. Lipid droplets were decreased in C18-4 cells exposed to BPF and in MA-10 cells exposed to BPTMC but increased in BPF, BPM, and BPTMC-exposed KGN cells. BPA and BPM exposure induced oxidative stress in MA-10 and KGN cells, respectively. In summary, structurally similar bisphenols displayed clear cell-line-specific differences in BMC and AED values for effects on cell viability and phenotypic endpoints. This approach, together with additional data on human exposure, may aid in the selection and prioritization of responsible replacements for BPA. .

Role of Adenylate Cyclase 9 in the Pharmacogenomic Response to Dalcetrapib: Clinical Paradigm and Molecular Mechanisms in Precision Cardiovascular Medicine

Following the neutral results of the dal-OUTCOMES trial, a genome-wide study identified the rs1967309 variant in the adenylate cyclase type 9 (ADCY9) gene on chromosome 16 as being associated with the risk of future cardiovascular events only in subjects taking dalcetrapib, a CETP (cholesterol ester transfer protein) modulator. Homozygotes for the minor A allele (AA) were protected from recurrent cardiovascular events when treated with dalcetrapib, while homozygotes for the major G allele (GG) had increased risk. Here, we present the current state of knowledge regarding the impact of rs1967309 in ADCY9 on clinical observations and biomarkers in dalcetrapib trials and the effects of mouse ADCY9 gene inactivation on cardiovascular physiology. Finally, we present our current model of the interaction between dalcetrapib and ADCY9 gene variants in the arterial wall macrophage, based on the intracellular role of CETP in the transfer of complex lipids from endoplasmic reticulum membranes to lipid droplets. Briefly, the concept is that dalcetrapib would inhibit CETP-mediated transfer of cholesteryl esters, resulting in a progressive inhibition of cholesteryl ester synthesis and free cholesterol accumulation in the endoplasmic reticulum. Reduced ADCY9 activity, by paradoxically leading to higher cyclic AMP levels and in turn increased cellular cholesterol efflux, could impart cardiovascular protection in rs1967309 AA patients. The ongoing dal-GenE trial recruited 6145 patients with the protective AA genotype and will provide a definitive answer to whether dalcetrapib will be protective in this population.

Phytogenic Water Additives Improve Broiler Growth Performance via Modulation of Intermediary Metabolism-Related Signaling Pathways

Simple Summary

Global concern around and heightened sensitivity to emerging drug-resistant superbugs have energized scientists to search for new alternatives to in-feed antibiotics. Powered by consumer demand for natural products and due to their beneficial effects on growth performances, phytogenics have become very popular and favorable alternatives. However, their mode of action has not been fully defined. Here, we showed that supplementation of phytogenics (AVSSL and SG) in water modulates peripheral metabolic pathways (reduction in hepatic fatty acid synthesis, mobilization of fat stores, and enhancement of muscle protein synthesis), which might explain, at least partly, their effect on feed efficiency improvement in broilers.

Abstract

A ban on the use of antibiotic growth promoters (AGPs) has fueled and promoted scientific research towards the identification of reliable and effective alternatives. The supplementation of phytogenics AV/SSL12 (AVSSL) and Superliv Gold (SG) in water has been shown to improve broiler feed efficiency (FE) via modulation of hypothalamic neuropeptides. However, their effects on peripheral metabolic pathways are still unknown. The present study was undertaken to determine the effects of AVSSL and SG on lipid and protein metabolism-associated pathways in various tissues. Day-old male Cobb 500 chicks (n = 288) were randomly assigned to 3 treatment groups, with 8 replicates of 12 birds each. The treatment groups were fed a basal diet and supplemented with AVSSL or SG in the drinking water at a rate of 2, 4, and 7 mL/100 birds/d during the starter, grower, and finisher phases, respectively. The control group were fed a basal diet with no additive supplementation. On d 35, liver, adipose, and muscle tissue were collected from one bird per pen (8 birds/group). Data were analyzed using Student’s T-test to compare one treatment group to the control using Graph Pad Prism version 6.0 for Windows. In the liver, the levels of phosphorylated acetyl-CoA carboxylase alpha (ACCα) were significantly increased in both the AVSSL and SG groups compared to the control. The hepatic expression of sterol regulatory element-binding protein cleavage-activating protein (SCAP) was significantly downregulated in both treated groups compared to the control. AVSSL supplementation downregulated the hepatic expression of SREBP-2 and adiponectin (AdipoQ), while SG administration upregulated hepatic AdipoR1/R2 mRNA abundances compared to the untreated group. Both AVSSL and SG treatments upregulated hepatic stearoyl-CoA desaturase-1 (SCD-1) gene expression compared to their untreated counterparts. In the adipose tissue, the levels of phosphorylated hormone-sensitive lipase (HSL) at Ser855/554 site were increased in both the AVSSL and SG groups compared to the control. However, ATGL protein expression was decreased in SG compared to the untreated group. In the muscle, the levels of phosphorylated mechanistic target of rapamycin (mTOR) were increased in the AVSSL, but decreased in the SG group compared to the control. Collectively, these data indicate that supplementation of the phytogenics AVSSL and SG in water reduced hepatic lipogenesis-related proteins and increased adipose tissue lipolysis- and muscle protein synthesis-associated targets, which might explain, at least partially, the improvement in FE observed in previous research.