Enoyl-CoA hydratase/3-hydroxyacyl CoA dehydrogenase is essential for the production of DHA in zebrafish

Lipidomics reveals effect of EHHADH in lung squamous cell

Lung squamous cell carcinoma (LUSC) and lung adenocarcinoma (LUAD) are two major pathological types of non-small cell lung cancer (NSCLC), characterized by distinct patterns of lipid metabolism. However, the molecular mechanisms underlying lipid metabolism reprogramming specific to LUSC remain poorly understood. This study aims to fill this gap by identifying and characterizing EHHADH (enoyl-CoA, hydratase/3-hydroxyacyl CoA dehydrogenase) as a key regulator of medium-chain fatty acid metabolism in LUSC. The peroxisomal L-bifunctional enzyme is one of the important elements to control the peroxisomal fatty acid beta-oxidation pathway. Through high-expression genes related to lipid metabolism were identified by data mining, the expression and regulatory effects of EHHADH in different cell lines were investigated. EHHADH was highly expressed in LUSC cells and exhibited different expression patterns from those in LUAD cells. Knockdown of EHHADH in LUSC cell lines led to a marked reduction in cell proliferation. RNA sequencing following EHHADH silencing demonstrated significant changes in the expression of lipid metabolism-related genes in different cell lines, such as AZGP1, CAV1, CYP3A4, NR2F2, NR3C2, and RARG. Lipidomics analysis further demonstrated that EHHADH plays a crucial role in regulating intracellular and extracellular lipid profiles. EHHADH knockdown resulted in increased levels of long-chain fatty acids and storage lipids, while decreased levels of medium-chain fatty acids. Conversely, overexpression of EHHADH reduced long-chain fatty acids and storage lipids, while increasing specific medium-chain fatty acids. These metabolic alterations were consistent with changes in lipid metabolism-related protein expression, supporting the molecular mechanistic role of EHHADH in lipid regulation. In conclusion, EHHADH functions as an important regulator of lipid metabolism in LUSC and plays a key role in the occurrence, progression, and treatment of lung cancer. The important impact of EHHADH in lipid metabolism disorders suggests potential utility as a biomarker for diagnosis and a target for personalized treatment strategies in lung cancer.

Endocrine and enzymatic shifts during insect diapause: a review of regulatory mechanisms

Insect diapause is a vital survival strategy that enables insects to enter a state of suspended development, allowing them to withstand unfavorable environmental conditions. During diapause, insects significantly lower their metabolic rate and build up energy reserves, which they gradually utilize throughout this period. The regulation of diapause involves a complex interaction of hormones and enzymes. Juvenile hormones (JHs) affect adults and larvae differently; in adults, the absence of JH typically triggers diapause, while in larvae, the presence of JH encourages this state. Ecdysteroids, which regulate molting and metamorphosis, are carefully controlled to prevent premature development. Reduced signaling of insulin-like peptides enhances stress resistance and promotes energy storage. Several enzymes play crucial roles in the metabolic adjustments necessary for diapause. These adjustments include the degradation of JH, the ecdysteroidogenic pathway, and the metabolism of fatty acids, glycogen, cryoprotectants, and stress responses. Understanding diapause's molecular and biochemical mechanisms is essential for fundamental entomological research and practical applications. Despite recent advances, many aspects of diapause regulation, especially the interactions among hormonal pathways and the role of enzymes, remain poorly understood. This review analyzes approximately 250 papers to consolidate current knowledge on the enzymatic and hormonal regulation of diapause. It offers a comprehensive overview of key processes based on recent studies and suggests future research directions to fill gaps in our understanding of this significant biological phenomenon. The review also lays the groundwork for enhancing pest control strategies and ecological conservation by deepening our understanding of diapause mechanisms.

Modelling Peroxisomal Disorders in Zebrafish

Peroxisomes are ubiquitous, dynamic, oxidative organelles with key functions in cellular lipid metabolism and redox homeostasis. They have been linked to healthy ageing, neurodegeneration, cancer, the combat of pathogens and viruses, and infection and immune responses. Their biogenesis relies on several peroxins (encoded by PEX genes), which mediate matrix protein import, membrane assembly, and peroxisome multiplication. Defects in peroxins or peroxisomal enzymes can result in severe disorders, including developmental and neurological abnormalities. The drive to understand the role of peroxisomes in human health and disease, as well as their functions in tissues and organs or during development, has led to the establishment of vertebrate models. The zebrafish (Danio rerio) has become an attractive vertebrate model organism to investigate peroxisomal functions. Here, we provide an overview of the visualisation of peroxisomes in zebrafish, as well as the peroxisomal metabolic functions and peroxisomal protein inventory in comparison to human peroxisomes. We then present zebrafish models which have been established to investigate peroxisomal disorders. These include model zebrafish for peroxisome biogenesis disorders/Zellweger Spectrum disorders, and single enzyme deficiencies, particularly adrenoleukodystrophy and fatty acid beta-oxidation abnormalities. Finally, we highlight zebrafish models for deficiencies of dually targeted peroxisomal/mitochondrial proteins. Advantages for the investigation of peroxisomes during development and approaches to the application of zebrafish models for drug screening are discussed.

Peroxisome Metabolism Pathway and EHHADH Expression are Downregulated in Macrophages in Neutrophilic Asthma

PURPOSE

Neutrophilic asthma (NA) is associated with more severe symptoms and poor responsiveness to inhaled corticosteroid therapy. Macrophages are the most abundant immune cells in the airway, but the role of macrophages in NA pathogenesis has not been fully studied. We hypothesized that dysregulation of peroxisome metabolism in macrophages may drive NA.

METHODS

We retrieved microarray datasets from the GEO Gene Expression Omnibus database by using induced sputum samples from eosinophilic and neutrophilic asthma patients as well as healthy controls. We identified key molecules in NA and validated the expression of the key genes in our cohort of asthma patients using quantitative polymerase chain reaction (PCR). Furthermore, immunofluorescence staining was performed to detect the expression and localization of the key molecule in bronchoalveolar lavage (BAL) cells from asthma patients and the murine model of neutrophilia-dominant allergic airway inflammation. The expression of the key molecule was also examined in mouse bone marrow-derived macrophages (BMDMs) by quantitative PCR and western blotting.

RESULTS

Enoyl-CoA hydratase and 3-hydroxyacyl CoA dehydrogenase (EHHADH), sterol carrier protein 2, and peroxisomal biogenesis factor 14 were identified as the key molecules and were downregulated in patients with NA or severe asthma. The peroxisomal fatty acid metabolism pathway was significantly downregulated in NA. In our cohort of asthma patients, the expression of EHHADH, a key enzyme of the peroxisomal fatty acid beta-oxidation, was significantly decreased in non-eosinophilic asthma patients and positively correlated with airflow limitation. EHHADH was primarily expressed in macrophages in BAL cells. EHHADH was downregulated in lipopolysaccharide (LPS)-induced M1-like macrophages in mouse BMDMs. Fenofibrate, an agonist of the peroxisome pathway, significantly inhibits LPS-induced macrophage M1 polarization.

CONCLUSIONS

EHHADH expression and the peroxisome metabolism pathway are downregulated in macrophages in patients with NA. This downregulation may contribute to macrophage M1 polarization and neutrophilic airway inflammation in asthma.

EHHADH deficiency regulates pexophagy and accelerates tubulointerstitial injury in diabetic kidney disease

Peroxisomal L-bifunctional enzyme (EHHADH) plays a role in the classic peroxisomal fatty acid β-oxidation pathway; however, the relationship between EHHADH expression and diabetic kidney disease has not been well understood. Here, we found that endogenous EHHADH levels were strongly correlated with the progression and severity of diabetic nephropathy in T2D patients. EHHADH knockout mice exhibited worsened renal tubular injury in diabetic mice. Furthermore, EHHADH is a modulator of pexophagy. In renal tubular epithelial cells (RTECs) in vitro, the knockdown of EHHADH induced a dramatic loss of peroxisomes. The loss of peroxisomes in EHHADH-deficient RTECs was restored by either an autophagic inhibitor 3-methyladenine or bafilomycin A1 both in vitro and in vivo. NBR1 was required for pexophagy in EHHADH-knockdown cells, where the level of reactive oxygen species (ROS) was increased, while inhibition of ROS blocked pexophagy. In summary, our findings revealed EHHADH deficiency accelerated renal injury in DKD as a modulator of pexophagy.

TMT-based quantitative proteomics analysis of Sprague-Dawley rats liver reveals Triphenyltin induced liver damage and lipid metabolism disorders

Triphenyltin (TPT) is a widely used pesticide that has a negative impact on biological health and production efficiency. In addition, TPT poses a threat to human health through the food chain and environmental pollution. However, the exact mechanism of TPT toxicity remains unclear. In this study, we investigated the hepatotoxicity of TPT and its effects on lipid metabolism using male SD rats as an animal model. Our results from HE and serum biochemical analysis suggested that TPT could damage liver structure and function, resulting in disruption of lipid metabolism. We therefore proceeded to analyze the proteomic response of rat liver tissue after 28 days of treatment with 2 mg/kg/d TPT. Our study demonstrates that TPT has a variety of effects on liver protein expression in rats. Through bioinformatic analysis, we observed significant changes in proteins related to fatty acid oxidation and synthesis due to TPT exposure. Furthermore, western blot and RT-qPCR experiments confirmed that TPT can affect lipid metabolism through the PPAR pathway. These findings suggest that TPT exposure can lead to liver damage, lipid accumulation and metabolic disorders.

Microbial oil, alone or paired with β-glucans, can control hypercholesterolemia in a zebrafish model

Dyslipidemia is often associated with unhealthy dietary habits, and many mammalian studies have explored the mode of action of certain bioactive compounds such as β-glucans and n-3 PUFAs to understand their potential to normalize the lipid metabolism. There are only a few investigations that adopted omic approaches to unveil their combined effect on hypercholesterolemia. Zebrafish (Danio rerio) was used as a model organism to reveal the efficacy of Schizochytrium oil and β-glucans (from Euglena gracilis and Phaeodactylum tricornutum) against cholesterol-rich diet induced dyslipidemia. One of the folowing four diets was fed to a particular group of fish: a control high-cholesterol diet, a Schizochytrium oil diet or one of the two diets containing the oil and β-glucan. The plasma HDL, expression of hepatic genes linked to, among others, ferric ion binding and plasma phosphatidylcholines were higher and plasma cholesterol esters and triacylglycerols were lower in the microbial oil-fed fish compared to the fish fed high cholesterol diet. While the fish fed a mix of microbial oil and Euglena β-glucan had lower plasma triacylglycerols and expression of hepatic genes linked to PPAR signaling pathway and enriched biosynthesis of plasma unsaturated fatty acids, the fish fed microbial oil-Phaeodactylum β-glucan combination had lower abundance of triacylglycerols rich in saturated and mono-unsaturated fatty acids and cholesterol esters in the plasma.

Peroxisome Proliferator-Activated Receptor Signaling-Mediated 13-S-Hydroxyoctadecenoic Acid Is Involved in Lipid Metabolic Disorder and Oxidative Stress in the Liver of Freshwater Drum, Aplodinotus grunniens

The appropriate level of dietary lipids is essential for the nutrient requirements, rapid growth, and health maintenance of aquatic animals, while excessive dietary lipid intake will lead to lipid deposition and affect fish health. However, the symptoms of excessive lipid deposition in the liver of freshwater drums (Aplodinotus grunniens) remain unclear. In this study, a 4-month rearing experiment feeding with high-fat diets and a 6-week starvation stress experiment were conducted to evaluate the physiological alteration and underlying mechanism associated with lipid deposition in the liver of A. grunniens. From the results, high-fat-diet-induced lipid deposition was associated with increased condition factor (CF), viscerosomatic index (VSI), and hepatosomatic index (HSI). Meanwhile, lipid deposition led to physiological and metabolic disorders, inhibited antioxidant capacity, and exacerbated the burden of lipid metabolism. Lipid deposition promoted fatty acid synthesis but suppressed catabolism. Specifically, the transcriptome and metabolome showed significant enrichment of lipid metabolism and antioxidant pathways. In addition, the interaction analysis suggested that peroxisome proliferator-activated receptor (PPAR)-mediated 13-S-hydroxyoctadecenoic acid (13 (s)-HODE) could serve as the key target in regulating lipid metabolism and oxidative stress during lipid deposition in A. grunniens. Inversely, with a lipid intake restriction experiment, PPARs were confirmed to regulate lipid expenditure and physiological homeostasis in A. grunniens. These results uncover the molecular basis of and provide specific molecular targets for fatty liver control and prevention, which are of great importance for the sustainable development of A. grunniens.