| 11. |
- Kerr, Alastair, et al.
(författare)
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The long noncoding RNA ADIPINT is a gatekeeper of pyruvate carboxylase function regulating human fat cell metabolism
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The pleiotropic function of long noncoding RNAs (lncRNAs) is well recognized, but their direct role in governing metabolic homeostasis is less understood. Herein, we describe a human adipocyte-specific lncRNA, ADIPINT, that regulates pyruvate carboxylase (PC) an enzyme pivotal to energy metabolism. With a novel approach, Targeted RNA-protein identification using Orthogonal Organic Phase Separation (TROOPS) and validation with electron microscopy, we show that ADIPINT binds to PC. ADIPINT knockdown alters the interactome and decreases the mitochondrial abundance and enzymatic activty of PC. Decreases in ADIPINT or PC expression reduce adipocyte lipid synthesis, breakdown and lipid content. In human white adipose tissue, ADIPINT expression is increased in obesity, linked to fat cell size, adipose insulin resistance and PC activity. Thus, we identify ADIPINT as a regulator of lipid metabolism in human white adipocytes, which at least in part is mediated through its interaction with PC.
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| 12. |
- Langin, Dominique, et al.
(författare)
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Gene organization and primary structure of human hormone-sensitive lipase: possible significance of a sequence homology with a lipase of Moraxella TA144, an antarctic bacterium
- 1993
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Ingår i: Proceedings of the National Academy of Sciences. - 1091-6490. ; 90:11, s. 4897-4901
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Tidskriftsartikel (refereegranskat)abstract
- The human hormone-sensitive lipase (HSL) gene encodes a 786-aa polypeptide (85.5 kDa). It is composed of nine exons spanning approximately 11 kb, with exons 2-5 clustered in a 1.1-kb region. The putative catalytic site (Ser423) and a possible lipid-binding region in the C-terminal part are encoded by exons 6 and 9, respectively. Exon 8 encodes the phosphorylation site (Ser551) that controls cAMP-mediated activity and a second site (Ser553) that is phosphorylated by 5'-AMP-activated protein kinase. Human HSL showed 83% identity with the rat enzyme and contained a 12-aa deletion immediately upstream of the phosphorylation sites with an unknown effect on the activity control. Besides the catalytic site motif (Gly-Xaa-Ser-Xaa-Gly) found in most lipases, HSL shows no homology with other known lipases or proteins, except for a recently reported unexpected homology between the region surrounding its catalytic site and that of the lipase 2 of Moraxella TA144, an antarctic psychrotrophic bacterium. The gene of lipase 2, which catalyses lipolysis below 4 degrees C, was absent in the genomic DNA of five other Moraxella strains living at 37 degrees C. The lipase 2-like sequence in HSL may reflect an evolutionarily conserved cold adaptability that might be of critical survival value when low-temperature-mobilized endogenous lipids are the primary energy source (e.g., in poikilotherms or hibernators). The finding that HSL at 10 degrees C retained 3- to 5-fold more of its 37 degrees C catalytic activity than lipoprotein lipase or carboxyl ester lipase is consistent with this hypothesis.
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| 13. |
- Lindvall, Håkan, et al.
(författare)
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A novel hormone-sensitive lipase isoform expressed in pancreatic beta -cells.
- 2004
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 279:5, s. 3828-3836
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Tidskriftsartikel (refereegranskat)abstract
- Hormone-sensitive lipase (HSL) is a key enzyme in fatty acid mobilization in many cell types. Two isoforms of HSL are known to date, namely HSLadi (84 kDa in rat) and HSLtes (130 kDa in rat). These are encoded by the same gene, with exons 1-9 encoding the parts that are common to both and an additional 5'-exon encoding the additional amino acids in HSLtes. HSL of various tissues, among these the islet of Langerhans, is larger than HSLadi, but not as large as HSLtes, indicating that there may be other 5'-coding exons. Here we describe the molecular basis for a novel 89-kDa HSL isoform that is expressed in -cells, adipocytes, adrenal glands, and ovaries in the rat and that is encoded by exons 1-9 and exon A, which is spliced to exon 1 and thereby introducing an upstream start codon. The additional 5'-base pairs encode a 43-amino acid peptide, which is highly positively charged. Conglomerates of HSL molecules are in close association with the secretory granules of the -cell, as determined by immunoelectron microscopy with antibodies targeting two separate regions of HSL. We have also determined that the human genomic sequence upstream of exon A has promoter activity in INS-1 cells as well as glucose sensing capability, mediating an increase in expression at high glucose concentration. The minimal promoter is present within 170 bp from the transcriptional start site and maximal glucose responsiveness is conferred by sequence within 850 bp from the transcriptional start site.
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| 14. |
- Massier, Lucas, et al.
(författare)
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An integrated single cell and spatial transcriptomic map of human white adipose tissue
- 2023
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Single-cell studies of human white adipose tissue (WAT) provide insights into the specialized cell types in the tissue. Here the authors combine publicly available and newly generated high-resolution and bulk transcriptomic results from multiple human datasets to provide a comprehensive cellular map of white adipose tissue. To date, single-cell studies of human white adipose tissue (WAT) have been based on small cohort sizes and no cellular consensus nomenclature exists. Herein, we performed a comprehensive meta-analysis of publicly available and newly generated single-cell, single-nucleus, and spatial transcriptomic results from human subcutaneous, omental, and perivascular WAT. Our high-resolution map is built on data from ten studies and allowed us to robustly identify >60 subpopulations of adipocytes, fibroblast and adipogenic progenitors, vascular, and immune cells. Using these results, we deconvolved spatial and bulk transcriptomic data from nine additional cohorts to provide spatial and clinical dimensions to the map. This identified cell-cell interactions as well as relationships between specific cell subtypes and insulin resistance, dyslipidemia, adipocyte volume, and lipolysis upon long-term weight changes. Altogether, our meta-map provides a rich resource defining the cellular and microarchitectural landscape of human WAT and describes the associations between specific cell types and metabolic states.
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| 15. |
- Raclot, Thierry, et al.
(författare)
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A role for hormone-sensitive lipase in the selective mobilization of adipose tissue fatty acids
- 2001
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Ingår i: Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids. - 1388-1981. ; 1532:1-2, s. 88-96
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Tidskriftsartikel (refereegranskat)abstract
- The mobilization of fatty acids from rat and human fat cells is selective according to molecular structure, and notably carbon atom chain length. This study aimed at examining whether the release of individual fatty acids from triacylglycerols (TAG) by hormone-sensitive lipase (HSL) plays a role in the selectivity of fatty acid mobilization. Recombinant rat and human HSL were incubated with a lipid emulsion. The hydrolysis of 18 individual fatty acids, ranging in chain length from 12 to 24 carbon atoms and in unsaturation degree from 0 to 3 double bond(s), was measured by comparing the composition of non-esterified fatty acids (NEFA) to that of the original TAG. The relative hydrolysis (% in NEFA/% in TAG) differed between fatty acids, being about 5-fold and 3-fold higher for the most(18:1n-7) than for the least (24:0) readily released fatty acid by recombinant rat and human HSL, respectively. Relationships were found between the chain length of fatty acids and their relative hydrolysis. Among 12-24 carbon atom saturated fatty acids, the relative hydrolysis markedly decreased (by about 5- and 3-times for recombinant rat and human HSL, respectively) with increasing chain length. We conclude that fatty acids are selectively released from TAG by HSL according to carbon atom chain length. These data provide insight on the mechanism by which fatty acids are selectively mobilized from fat cells.
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| 16. |
- Raclot, Thierry, et al.
(författare)
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Fatty acid specificity of hormone-sensitive lipase: implication in the selective hydrolysis of triacylglycerols
- 2001
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Ingår i: Journal of Lipid Research. - 1539-7262. ; 42:12, s. 2049-2057
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Tidskriftsartikel (refereegranskat)abstract
- The selective mobilization of fatty acids from white fat cells depends on their molecular structure, in particular the degree of unsaturation. The present study was designed to examine if the release of fatty acids by hormone-sensitive lipase (HSL) in vitro i) is influenced by the amount of unsaturation, ii) depends on the temperature, and iii) could explain the selective pattern of fatty acid mobilization and notably the preferential mobilization of certain highly unsaturated fatty acids. Recombinant rat and human HSL were incubated with a lipid emulsion. The hydrolysis of 35 individual fatty acids, ranging in chain length from 12 to 24 carbon atoms and in unsaturation from 0 to 6 double bonds was measured. Fatty acid composition of in vitro released NEFA was compared with that of fat cell triacylglycerols (TAG), the ratio % NEFA/% TAG being defined as the relative hydrolysis. The relative hydrolysis of individual fatty acids differed widely, ranging from 0.44 (24:ln-9) to 1.49 (18:ln-7) with rat HSL, and from 0.38 (24:ln-9) to 1.67 (18:ln-7) with human HSL. No major difference was observed between rat and human HSL. The relative release was dependent on the number of double bonds according to chain length. The amount of fatty acid released by recombinant rat HSL was decreased but remained robust at 4 degreesC compared with 37 degreesC, and the relative hydrolysis of some individual fatty acids was affected. The relative hydrolysis of fatty acids moderately, weakly, and highly mobilized by adipose tissue in vivo was similar and close to unity in vitro. We conclude that i) the release of fatty acids by HSL is only slightly affected by their degree of unsaturation, ii) the ability of HSL to efficiently and selectively release fatty acids at low temperature could reflect a cold adaptability for poikilotherms or hibernators when endogenous lipids are needed, and iii) the selectivity of fatty acid hydrolysis by HSL does not fully account for the selective pattern of fatty acid mobilization, but could contribute to explain the preferential mobilization of some highly unsaturated fatty acids compared with others.
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| 17. |
- Stenson, Lena, et al.
(författare)
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Molecular cloning, genomic organization, and expression of a testicular isoform of hormone-sensitive lipase
- 1996
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Ingår i: Genomics. - : Elsevier BV. - 1089-8646 .- 0888-7543. ; 35:3, s. 441-447
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Tidskriftsartikel (refereegranskat)abstract
- By catalyzing the rate-limiting step in adipose tissue lipolysis, hormone-sensitive lipase (HSL) is an important regulator of energy homeostasis. The role and importance of HSL in tissues other than adipose are poorly understood. We report here the cloning and expression of a testicular isoform, designated HSLtes. Due to an addition of amino acids at the NH2-termini, rat and human HSLtes consist of 1068 and 1076 amino acids, respectively, compared to the 768 and 775 amino acids, respectively, of the adipocyte isoform (HSLadi). A novel exon of 1.2 kb, encoding the human testis-specific amino acids, was isolated and mapped to the HSL gene, 16 kb upstream of the exons encoding HSLadi. The transcribed mRNA of 3.9 kb was specifically expressed in testis. No significant similarity with other known proteins was found for the testis-specific sequence. The amino acid composition differs from the HSLadi sequence, with a notable hydrophilic character and a high content of prolines and glutamines. COS cells, transfected by the 3.9-kb human testis cDNA, expressed a protein of the expected molecular mass (M(r) approximately 120,000) that exhibited catalytic activity similar to that of HSLadi. Immunocytochemistry localized HSL to elongating spermatids and spermatozoa; HSL was not detected in interstitial cells.
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| 18. |
- Stocks, Tanja, et al.
(författare)
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Change in Proportional Protein Intake in a 10-Week Energy-Restricted Low- or High-Fat Diet, in Relation to Changes in Body Size and Metabolic Factors
- 2013
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Ingår i: Obesity Facts. - : S. Karger AG. - 1662-4025 .- 1662-4033. ; 6:3, s. 217-227
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Forskningsöversikt (refereegranskat)abstract
- Objective: To investigate in a secondary analysis of a randomised trial the effects of a low-/high-fat diet and reported change from baseline in energy% from protein (prot%), in relation to changes in body size and metabolic factors. Methods: Obese adults (n = 771) were randomised to a 600 kcal energy-deficient low-fat (20-25 fat%) or high-fat (40-45 fat%) diet over 10 weeks. Dietary intake data at baseline and during the intervention were available in 585 completers. We used linear regression to calculate the combined effects of randomised group and groups of prot% change (<-2 /-2 to 2/>2) on outcomes. Results: The low-fat group with >2 prot% increase lost 1.1 kg more weight (p = 0.03) and reduced cholesterol by 0.25 mmol/l more (p = 0.003) than the high-fat group with >2 prot% decrease. These differences were 2.5-fold and 1.8-fold greater than the differences between the low-fat and high-fat groups while not considering prot% change. The high-fat group reduced plasma triglycerides more than the low-fat group, but not compared to those in the low-fat group with >2 units prot% increase (p fat-protein interaction = 0.01). Conclusions: Under energy restriction, participants on a low-fat diet who had increased the percentage energy intake from protein showed the greatest reduction in weight and cholesterol, and a triglyceride reduction equally large to that of participants on a high-fat diet.
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| 19. |
- Stocks, Tanja, et al.
(författare)
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TFAP2B influences the effect of dietary fat on weight loss under energy restriction
- 2012
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:8, s. e43212-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Numerous gene loci are related to single measures of body weight and shape. We investigated if 55 SNPs previously associated with BMI or waist measures, modify the effects of fat intake on weight loss and waist reduction under energy restriction.Methods and Findings: Randomized controlled trial of 771 obese adults. (Registration: ISRCTN25867281.) One SNP was selected for replication in another weight loss intervention study of 934 obese adults. The original trial was a 10-week 600 kcal/d energy-deficient diet with energy percentage from fat (fat%) in range of 20-25 or 40-45. The replication study used an 8-weeks diet of 880 kcal/d and 20 fat%; change in fat% intake was used for estimation of interaction effects. The main outcomes were intervention weight loss and waist reduction. In the trial, mean change in fat% intake was -12/+4 in the low/high-fat groups. In the replication study, it was -23/-12 among those reducing fat% more/less than the median. TFAP2B-rs987237 genotype AA was associated with 1.0 kg (95% CI, 0.4; 1.6) greater weight loss on the low-fat, and GG genotype with 2.6 kg (1.1; 4.1) greater weight loss on the high-fat (interaction p-value; p=0.00007). The replication study showed a similar (non-significant) interaction pattern. Waist reduction results generally were similar. Study-strengths include (i) the discovery study randomised trial design combined with the replication opportunity (ii) the strict dietary intake control in both studies (iii) the large sample sizes of both studies. Limitations are (i) the low minor allele frequency of the TFAP2B polymorphism, making it hard to investigate non-additive genetic effects (ii) the different interventions preventing identical replication-discovery study designs (iii) some missing data for non-completers and dietary intake. No adverse effects/outcomes or side-effects were observed.Conclusions: Under energy restriction, TFAP2B may modify the effect of dietary fat intake on weight loss and waist reduction.
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