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Journal of Dairy Science Aug 2022Activated autophagy-lysosomal pathway (ALP) can degrade virtually all kinds of cellular components, including intracellular lipid droplets, especially during catabolic...
Activated autophagy-lysosomal pathway (ALP) can degrade virtually all kinds of cellular components, including intracellular lipid droplets, especially during catabolic conditions. Sustained lipolysis and increased plasma fatty acids concentrations are characteristic of dairy cows with hyperketonemia. However, the status of ALP in adipose tissue during this physiological condition is not well known. The present study aimed to ascertain whether lipolysis is associated with activation of ALP in adipose tissues of dairy cows with hyperketonemia and in calf adipocytes. In vivo, blood and subcutaneous adipose tissue (SAT) biopsies were collected from nonhyperketonemic (nonHYK) cows [blood β-hydroxybutyrate (BHB) concentration <1.2 mM, n = 10] and hyperketonemic (HYK) cows (blood BHB concentration 1.2-3.0 mM, n = 10) with similar days in milk (range: 3-9) and parity (range: 2-4). In vitro, calf adipocytes isolated from 5 healthy Holstein calves (1 d old, female, 30-40 kg) were differentiated and used for (1) treatment with lipolysis inducer isoproterenol (ISO, 10 µM, 3 h) or mammalian target of rapamycin inhibitor Torin1 (250 nM, 3 h), and (2) pretreatment with or without the ALP inhibitor leupeptin (10 μg/mL, 4 h) followed by ISO (10 µM, 3 h) treatment. Compared with nonHYK cows, serum concentration of free fatty acids was greater and serum glucose concentration, DMI, and milk yield were lower in HYK cows. In SAT of HYK cows, ratio of phosphorylated hormone-sensitive lipase to hormone-sensitive lipase, and protein abundance of adipose triacylglycerol lipase were greater, but protein abundance of perilipin 1 (PLIN1) and cell death-inducing DNA fragmentation factor-α-like effector c (CIDEC) was lower. In addition, mRNA abundance of autophagy-related 5 (ATG5), autophagy-related 7 (ATG7), and microtubule-associated protein 1 light chain 3 beta (MAP1LC3B), protein abundance of lysosome-associated membrane protein 1, and cathepsin D, and activity of β-N-acetylglucosaminidase were greater, whereas protein abundance of sequestosome-1 (p62) was lower in SAT of HYK cows. In calf adipocytes, treatment with ISO or Torin1 decreased protein abundance of PLIN1, and CIDEC, and triacylglycerol content in calf adipocytes, but increased glycerol content in the supernatant of calf adipocytes. Moreover, the mRNA abundance of ATG5, ATG7, and MAP1LC3B was upregulated, the protein abundance of lysosome-associated membrane protein 1, cathepsin D, and activity of β-N-acetylglucosaminidase were increased, whereas the protein abundance of p62 was decreased in calf adipocytes treated with ISO or Torin1 compared with control group. Compared with treatment with ISO alone, the protein abundance of p62, PLIN1, and CIDEC, and triacylglycerol content in calf adipocytes were higher, but the glycerol content in the supernatant of calf adipocytes was lower in ISO and leupeptin co-treated group. Overall, these data indicated that activated ALP is associated with increased lipolysis in adipose tissues of dairy cows with hyperketonemia and in calf adipocytes.
Topics: 3-Hydroxybutyric Acid; Acetylglucosaminidase; Adipose Tissue; Animals; Autophagy; Cathepsin D; Cattle; Cattle Diseases; Female; Glycerol; Ketosis; Lactation; Leupeptins; Lipolysis; Lysosomal Membrane Proteins; Lysosomes; Mammals; Pregnancy; RNA, Messenger; Sterol Esterase; Triglycerides
PubMed: 35688731
DOI: 10.3168/jds.2021-21287 -
Cells Oct 2021Lysosomal acid lipase (LAL) is the sole enzyme known to be responsible for the hydrolysis of cholesteryl esters and triglycerides at an acidic pH in lysosomes, resulting...
Lysosomal acid lipase (LAL) is the sole enzyme known to be responsible for the hydrolysis of cholesteryl esters and triglycerides at an acidic pH in lysosomes, resulting in the release of unesterified cholesterol and free fatty acids. However, the role of LAL in diet-induced adaptations is largely unexplored. In this study, we demonstrate that feeding a Western-type diet to Lal-deficient (LAL-KO) mice triggers metabolic reprogramming that modulates gut-liver cholesterol homeostasis. Induction of ileal fibroblast growth factor 15 (three-fold), absence of hepatic cholesterol 7α-hydroxylase expression, and activation of the ERK phosphorylation cascade results in altered bile acid composition, substantial changes in the gut microbiome, reduced nutrient absorption by 40%, and two-fold increased fecal lipid excretion in LAL-KO mice. These metabolic adaptations lead to impaired bile acid synthesis, lipoprotein uptake, and cholesterol absorption and ultimately to the resistance of LAL-KO mice to diet-induced obesity. Our results indicate that LAL-derived lipolytic products might be important metabolic effectors in the maintenance of whole-body lipid homeostasis.
Topics: Animals; Bile Acids and Salts; Dysbiosis; Lipid Metabolism; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Obesity; Sterol Esterase
PubMed: 34685599
DOI: 10.3390/cells10102619 -
American Journal of Physiology.... Oct 2020Obesity and type 2 diabetes are frequently complicated by excess fat accumulation in the liver, which is known as nonalcoholic fatty liver disease (NAFLD). In this... (Review)
Review
Obesity and type 2 diabetes are frequently complicated by excess fat accumulation in the liver, which is known as nonalcoholic fatty liver disease (NAFLD). In this context, liver steatosis develops as a result of the deregulation of pathways controlling de novo lipogenesis and fat catabolism. Recent evidences suggest the clinical relevance of a reduction in the activity of lysosomal acid lipase (LAL), which is a key enzyme for intracellular fat disposal, in patients with NAFLD. In this review, we provided a comprehensive overview of the critical steps in hepatic fat metabolism and alterations in these pathways in NAFLD, with a special focus on lipophagy and LAL activity. During NAFLD, hepatic fat metabolism is impaired at several levels, which is significantly contributed to by impaired lipophagy, in which reduced LAL activity may play an important role. For further research and intervention in NAFLD, targeting LAL activity may provide interesting perspectives.
Topics: Autophagy; Humans; Lipid Metabolism; Lipolysis; Liver; Lysosomes; Non-alcoholic Fatty Liver Disease; Sterol Esterase
PubMed: 32812776
DOI: 10.1152/ajpgi.00049.2020 -
Lipids in Health and Disease Feb 2022Colorectal cancer (CRC) is one of the most common cancers worldwide characterized by disparities in age, gender, race and anatomic sites. The mechanism underlying...
BACKGROUND
Colorectal cancer (CRC) is one of the most common cancers worldwide characterized by disparities in age, gender, race and anatomic sites. The mechanism underlying pathogenesis, progression and disparities of CRC remains unclear. This study aims to reveal the association of expression levels of enzymes related to cholesteryl ester (CE) metabolism with pathogenesis, progression and disparities of CRC.
METHODS
The differences in gene expression levels were analyzed for enzymes in CE synthesis (acyl CoA: cholesterol acyltransferase 1 and 2, ACAT1, and ACAT2), and in CE hydrolysis (neutral cholesterol ester hydrolase, NCEH1 and lysosomal acid lipase, LAL) on TNMplot platform between CRC and normal colorectal tissues (NCT) in a large cohort. The differences in protein expression levels for these enzymes were determined by Immunochemistry (IHC) performed on tissue microarray containing 96 pairs of CRC and benign colorectal tissues (BCT) from different patient populations. The expression level represented as IHC score of each enzyme was compared between CRC and BCT in entire population and populations stratified by race, gender and anatomic sites. Student's t-test, Fisher exact test and ANOVA were used for data analysis. Significant p value was set at P<0.05.
RESULTS
The gene expression level of ACAT1 was significantly lower in CRC than in NCT (P = 2.15e-119). The gene expression level of ACAT2 was not statistically different between CRC and NCT. The gene expression level of LIPA (encoding LAL) was significantly higher in CRC than in NCT (P = 2.01e-14). No data was found for the gene expression level of NCEH1. The IHC score of ACAT1was significantly lower in CRC than in BCT in all studied populations and in sub site of colon, but not in that of rectum. The IHC score of ACAT2 was not statistically different between CRC and BCT. IHC score of NCEH1 was significantly higher in CRC than in BCT only in African American (AA) population. The IHC score of LAL was significantly higher in CRC than in BCT in all studied populations and in all sub sites. In addition, decreased ACAT1 in CRC significantly correlated to progression of CRC: the lower IHC score of ACAT1, the more advanced clinical stage of CRC will be.
CONCLUSIONS
This study revealed that altered expression levels in enzymes related to CE metabolism highly correlate to the pathogenesis, clinical progression and disparities of CRC. The results will add revenue in elucidating mechanisms underlying progression of CRC, and shed light on seeking biomarkers and exploring therapeutic targets for CRC in a new direction.
Topics: Cholesterol Esters; Colorectal Neoplasms; Humans; Sterol Esterase; Sterol O-Acyltransferase
PubMed: 35172832
DOI: 10.1186/s12944-022-01629-7 -
World Journal of Gastroenterology Aug 2019Lysosomal acid lipase (LAL) plays a key role in intracellular lipid metabolism. Reduced LAL activity promotes increased multi-organ lysosomal cholesterol ester storage,... (Review)
Review
Lysosomal acid lipase (LAL) plays a key role in intracellular lipid metabolism. Reduced LAL activity promotes increased multi-organ lysosomal cholesterol ester storage, as observed in two recessive autosomal genetic diseases, Wolman disease and Cholesterol ester storage disease. Severe liver steatosis and accelerated liver fibrosis are common features in patients with genetic LAL deficiency. By contrast, few reliable data are available on the modulation of LAL activity and on the epigenetic and metabolic factors capable of regulating its activity in subjects without homozygous mutations of the Lipase A gene. In the last few years, a less severe and non-genetic reduction of LAL activity was reported in children and adults with non-alcoholic fatty liver disease (NAFLD), suggesting a possible role of LAL reduction in the pathogenesis and progression of the disease. Patients with NAFLD show a significant, progressive reduction of LAL activity from simple steatosis to non-alcoholic steatohepatitis and cryptogenic cirrhosis. Among cirrhosis of different etiologies, those with cryptogenic cirrhosis show the most significant reductions of LAL activity. These findings suggest that the modulation of LAL activity may become a possible new therapeutic target for patients with more advanced forms of NAFLD. Moreover, the measurement of LAL activity may represent a possible new marker of disease severity in this clinical setting.
Topics: Biomarkers; Cholesterol Esters; Disease Progression; Dried Blood Spot Testing; Enzyme Replacement Therapy; Humans; Lipid Metabolism; Liver; Liver Cirrhosis; Liver Function Tests; Lysosomes; Non-alcoholic Fatty Liver Disease; Severity of Illness Index; Sterol Esterase; Triglycerides; Wolman Disease
PubMed: 31435171
DOI: 10.3748/wjg.v25.i30.4172 -
The American Journal of Pathology Feb 2021Utilization of proper preclinical models accelerates development of immunotherapeutics and the study of the interplay between human malignant cells and immune cells....
Utilization of proper preclinical models accelerates development of immunotherapeutics and the study of the interplay between human malignant cells and immune cells. Lysosomal acid lipase (LAL) is a critical lipid hydrolase that generates free fatty acids and cholesterol. Ablation of LAL suppresses immune rejection and allows growth of human lung cancer cells in lal mice. In the lal lymph nodes, the percentages of both T- and B-regulatory cells (Tregs and Bregs, respectively) are increased, with elevated expression of programmed death-ligand 1 and IL-10, and decreased expression of interferon-γ. Levels of enzymes in the glucose and glutamine metabolic pathways are elevated in Tregs and Bregs of the lal lymph nodes. Pharmacologic inhibitor of pyruvate dehydrogenase, which controls the transition from glycolysis to the citric acid cycle, effectively reduces Treg and Breg elevation in the lal lymph nodes. Blocking the mammalian target of rapamycin or reactivating peroxisome proliferator-activated receptor γ, an LAL downstream effector, reduces lal Treg and Breg elevation and PD-L1 expression in lal Tregs and Bregs, and improves human cancer cell rejection. Treatment with PD-L1 antibody also reduces Treg and Breg elevation in the lal lymph nodes and improves human cancer cell rejection. These observations conclude that LAL-regulated lipid metabolism is essential to maintain antitumor immunity.
Topics: Animals; B-Lymphocytes, Regulatory; Disease Models, Animal; Heterografts; Homeostasis; Humans; Lymph Nodes; Mice; Mice, Knockout; Neoplasm Transplantation; Neoplasms, Experimental; Sterol Esterase; T-Lymphocytes, Regulatory; Tumor Escape
PubMed: 33159889
DOI: 10.1016/j.ajpath.2020.10.007 -
Journal of Dairy Science Jul 2021Novel antihypercholesterolemic bioactive peptides (BAP) from peptic camel whey protein hydrolysates (CWPH) were generated at different time, temperature, and enzyme...
New insights into the cholesterol esterase- and lipase-inhibiting potential of bioactive peptides from camel whey hydrolysates: Identification, characterization, and molecular interaction.
Novel antihypercholesterolemic bioactive peptides (BAP) from peptic camel whey protein hydrolysates (CWPH) were generated at different time, temperature, and enzyme concentration (%). Hydrolysates showed higher pancreatic lipase- (PL; except 3 CWPH) and cholesterol esterase (CE)-inhibiting potential, as depicted by lower half-maximal inhibitory concentration values (IC values) compared with nonhydrolyzed camel whey proteins (CWP). Peptide sequencing and in silico data depicted that most BAP from CWPH could bind active site of PL, whereas as only 3 peptides could bind the active site of CE. Based on higher number of reactive residues in the BAP and greater number of substrate binding sites, FCCLGPVPP was identified as a potential CE-inhibitory peptide, and PAGNFLPPVAAAPVM, MLPLMLPFTMGY, and LRFPL were identified as PL inhibitors. Molecular docking of selected peptides showed hydrophilic and hydrophobic interactions between peptides and target enzymes. Thus, peptides derived from CWPH warrant further investigation as potential candidates for adjunct therapy for hypercholesterolemia.
Topics: Animals; Camelus; Lipase; Molecular Docking Simulation; Peptides; Protein Hydrolysates; Sterol Esterase; Whey; Whey Proteins
PubMed: 33934858
DOI: 10.3168/jds.2020-19868 -
Journal of Lipid Research May 2022Lipid droplets (LDs) are multifunctional organelles that regulate energy storage and cellular homeostasis. The first step of triacylglycerol hydrolysis in LDs is...
Lipid droplets (LDs) are multifunctional organelles that regulate energy storage and cellular homeostasis. The first step of triacylglycerol hydrolysis in LDs is catalyzed by adipose triglyceride lipase (ATGL), deficiency of which results in lethal cardiac steatosis. Although hormone-sensitive lipase (HSL) functions as a diacylglycerol lipase in the heart, we hypothesized that activation of HSL might compensate for ATGL deficiency. To test this hypothesis, we crossed ATGL-KO (AKO) mice and cardiac-specific HSL-overexpressing mice (cHSL) to establish homozygous AKO mice and AKO mice with cardiac-specific HSL overexpression (AKO+cHSL). We found that cardiac triacylglycerol content was 160-fold higher in AKO relative to Wt mice, whereas that of AKO+cHSL mice was comparable to the latter. In addition, AKO cardiac tissues exhibited reduced mRNA expression of PPARα-regulated genes and upregulation of genes involved in inflammation, fibrosis, and cardiac stress. In contrast, AKO+cHSL cardiac tissues exhibited expression levels similar to those observed in Wt mice. AKO cardiac tissues also exhibited macrophage infiltration, apoptosis, interstitial fibrosis, impaired systolic function, and marked increases in ceramide and diacylglycerol contents, whereas no such pathological alterations were observed in AKO+cHSL tissues. Furthermore, electron microscopy revealed considerable LDs, damaged mitochondria, and disrupted intercalated discs in AKO cardiomyocytes, none of which were noted in AKO+cHSL cardiomyocytes. Importantly, the life span of AKO+cHSL mice was comparable to that of Wt mice. HSL overexpression normalizes lipotoxic cardiomyopathy in AKO mice and the findings highlight the applicability of cardiac HSL activation as a therapeutic strategy for ATGL deficiency-associated lipotoxic cardiomyopathies.
Topics: Animals; Cardiomyopathies; Fibrosis; Lipase; Lipolysis; Mice; Myocytes, Cardiac; Sterol Esterase; Triglycerides
PubMed: 35283217
DOI: 10.1016/j.jlr.2022.100194 -
Molecules (Basel, Switzerland) Jul 2023sp. D01, capable of growing in tributyrin medium, was isolated from the gut microbiota of yellow mealworm. By using in silico analyses, we discovered a hypothesized...
sp. D01, capable of growing in tributyrin medium, was isolated from the gut microbiota of yellow mealworm. By using in silico analyses, we discovered a hypothesized esterase encoding gene in the D01 bacterium, and its encoded protein, EstD04, was classified as a bacterial hormone-sensitive lipase (bHSL) of the type IV lipase family. The study revealed that the recombinant EstD04-His(6x) protein exhibited esterase activity and broad substrate specificity, as it was capable of hydrolyzing -nitrophenyl derivatives with different acyl chain lengths. By using the most favorable substrate -nitrophenyl butyrate (C), we defined the optimal temperature and pH value for EstD04 esterase activity as 40 °C and pH 8, respectively, with a catalytic efficiency (/) of 6.17 × 10 mM s at 40 °C. EstD04 demonstrated high stability between pH 8 and 10, and thus, it might be capably used as an alkaline esterase in industrial applications. The addition of Mg and NH, as well as DMSO, could stimulate EstD04 enzyme activity. Based on bioinformatic motif analyses and tertiary structural simulation, we determined EstD04 to be a typical bHSL protein with highly conserved motifs, including a triad catalytic center (Ser, Glu, and His), two cap regions, hinge sites, and an oxyanion hole, which are important for the type IV enzyme activity. Moreover, the sequence analysis suggested that the two unique discrete cap regions of EstD04 may contribute to its alkali mesophilic nature, allowing EstD04 to exhibit extremely distinct physiological properties from its evolutionarily closest esterase.
Topics: Animals; Esterases; Tenebrio; Amino Acid Sequence; Pseudomonas; Gastrointestinal Microbiome; Sterol Esterase; Bacteria; Substrate Specificity; Hydrogen-Ion Concentration; Cloning, Molecular; Enzyme Stability
PubMed: 37513282
DOI: 10.3390/molecules28145410 -
Nutrients Jul 2023Combining exercise with fasting is known to boost fat mass-loss, but detailed analysis on the consequential mobilization of visceral and subcutaneous WAT-derived fatty...
Combining exercise with fasting is known to boost fat mass-loss, but detailed analysis on the consequential mobilization of visceral and subcutaneous WAT-derived fatty acids has not been performed. In this study, a subset of fasted male rats (66 h) was submitted to daily bouts of mild exercise. Subsequently, by using gas chromatography-flame ionization detection, the content of 22 fatty acids (FA) in visceral (v) versus subcutaneous (sc) white adipose tissue (WAT) depots was compared to those found in response to the separate events. Findings were related to those obtained in serum and liver samples, the latter taking up FA to increase gluconeogenesis and ketogenesis. Each separate intervention reduced scWAT FA content, associated with increased levels of adipose triglyceride lipase (ATGL) protein despite unaltered AMP-activated protein kinase (AMPK) Thr172 phosphorylation, known to induce ATGL expression. The mobility of FAs from vWAT during fasting was absent with the exception of the MUFA 16:1 n-7 and only induced by combining fasting with exercise which was accompanied with reduced hormone sensitive lipase (HSL) Ser563 and increased Ser565 phosphorylation, whereas ATGL protein levels were elevated during fasting in association with the persistently increased phosphorylation of AMPK at Thr172 both during fasting and in response to the combined intervention. As expected, liver FA content increased during fasting, and was not further affected by exercise, despite additional FA release from vWAT in this condition, underlining increased hepatic FA metabolism. Both fasting and its combination with exercise showed preferential hepatic metabolism of the prominent saturated FAs C:16 and C:18 compared to the unsaturated FAs 18:1 n-9 and 18:2 n-6:1. In conclusion, depot-specific differences in WAT fatty acid molecule release during fasting, irrelevant to their degree of saturation or chain length, are mitigated when combined with exercise, to provide fuel to surrounding organs such as the liver which is correlated with increased ATGL/ HSL ratios, involving AMPK only in vWAT.
Topics: Rats; Male; Animals; Sterol Esterase; Fatty Acids; AMP-Activated Protein Kinases; Lipase; Lipolysis; Obesity; Fasting; Adipose Tissue
PubMed: 37513513
DOI: 10.3390/nu15143095