scholarly journals Inhibition of hormone-sensitive lipase gene expression by cAMP and phorbol esters in 3T3-F442A and BFC-1 adipocytes

1996 ◽  
Vol 318 (3) ◽  
pp. 1057-1063 ◽  
Author(s):  
Emmanuelle PLÉE-GAUTIER ◽  
Jacques GROBER ◽  
Eric DUPLUS ◽  
Dominique LANGIN ◽  
Claude FOREST
Keyword(s):  
Gene Expression ◽  
Hormonal Regulation ◽  
Phorbol Esters ◽  
Total Activity ◽  
Hormone Sensitive Lipase ◽  
Protein Synthesis Inhibitor ◽  
Synthesis Inhibitor ◽  
Lipase Gene ◽  
Mouse Cdna ◽  
Hormone Sensitive

Hormone-sensitive lipase (HSL) catalyses the rate-limiting step in adipocyte lipolysis. Short-term hormonal regulation of HSL activity is well characterized, whereas little is known about the control of HSL gene expression. We have measured HSL mRNA content of 3T3-F442A and BFC-1 adipocytes in response to the cAMP analogue 8-(4-chlorophenylthio)-cAMP (8-CPT-cAMP) and to the phorbol ester phorbol 12-myristate 13-acetate (PMA) by Northern blot, using a specific mouse cDNA fragment. Treatment of the cells for 12 or 6 h with, respectively, 0.5 mM 8-CPT-cAMP or 1 µM PMA produced a maximal decrease of about 60% in HSL mRNA. These effects were unaffected by the protein-synthesis inhibitor anisomycin, suggesting that cAMP and PMA actions were direct. The reduction in HSL mRNA was accompanied by a reduction in HSL total activity. The intracellular routes that cAMP and PMA follow for inducing such an effect seemed clearly independent. (i) After desensitization of the protein kinase C regulation pathway by a 24 h treatment of the cells with 1 µM PMA, PMA action was abolished whereas cAMP was still fully active. (ii) Treatment with saturating concentrations of both agents produced an additive effect. (iii) The synthetic glucocorticoid dexamethasone had no proper effect on HSL gene expression but potentiated cAMP action without affecting PMA action. cAMP inhibitory action on HSL is unexpected. Indeed, the second messenger of catecholamines is the main activator of HSL by phosphorylation. We envision that a long-term cAMP treatment of adipocytes induces a counter-regulatory process that reduces HSL content and, ultimately, limits fatty acid depletion from stored triacylglycerols.

The hormone-sensitive lipase gene and body composition: the HERITAGE Family Study

2002 ◽  
Vol 26 (2) ◽  
pp. 220-227 ◽  
Author(s):  
C Garenc ◽  
L Pérusse ◽  
YC Chagnon ◽  
T Rankinen ◽  
J Gagnon ◽  
...  
Keyword(s):  
Body Composition ◽  
Family Study ◽  
Hormone Sensitive Lipase ◽  
Lipase Gene ◽  
Hormone Sensitive

Tri-iodothyronine and cycloheximide enhance insulin-like growth factor-binding protein-1 gene expression in human hepatoma cells

1993 ◽  
Vol 10 (1) ◽  
pp. 7-13 ◽  
Author(s):  
M Angervo ◽  
P Leinonen ◽  
R Koistinen ◽  
M Julkunen ◽  
M Seppälä
Keyword(s):  
Gene Expression ◽  
Thyroid Hormone ◽  
Hepatoma Cells ◽  
Protein Synthesis Inhibitor ◽  
Human Hepatoma ◽  
Human Hepatoma Cells ◽  
Synthesis Inhibitor ◽  
Genes Encoding ◽  
Protein Mediator

ABSTRACT The growth-regulating actions of IGFs are modulated by their binding proteins (IGFBPs). The serum concentration of IGFBP-1 is down-regulated by insulin, and in-vitro studies have demonstrated that IGFBP-1 secretion from various tissues and cells can be stimulated by theophylline, forskolin, oestrogen and progesterone. We have studied the effects and mechanisms of thyroid hormone action on IGFBP-1 gene expression and secretion by human hepatoma cells in vitro. Tri-iodothyronine dose-dependently enhanced IGFBP-1 secretion in serum-free HepG2 cell cultures after 24–48 h of exposure, as measured by a specific immunofluorometric assay. This was accompanied by an increase (+ 50%) in the amount of IGFBP-1 mRNA, which could be prevented by cycloheximide, a protein synthesis inhibitor. Cycloheximide transiently enhanced (+ 200%) the accumulation of IGFBP-1 mRNA at 3–12 h of incubation, when no effect of tri-iodothyronine was observed. It is concluded that thyroid hormone stimulates IGFBP-1 secretion slowly by enhancing IGFBP-1 gene expression by a protein mediator. The acute stimulation of IGFBP-1 gene transcription by cycloheximide associates this gene with a number of growth-related genes encoding growth- and tumour-associated peptides.

A Cold-Adapted Lipase of an Alaskan Psychrotroph,Pseudomonas sp. Strain B11-1: Gene Cloning and Enzyme Purification and Characterization

1998 ◽  
Vol 64 (2) ◽  
pp. 486-491 ◽  
Author(s):  
Dong-Won Choo ◽  
Tatsuo Kurihara ◽  
Takeshi Suzuki ◽  
Kenji Soda ◽  
Nobuyoshi Esaki
Keyword(s):  
Amino Acid ◽  
Enzyme Purification ◽  
Hormone Sensitive Lipase ◽  
Amino Acid Residues ◽  
Lipase Gene ◽  
Positional Specificity ◽  
Cold Adapted ◽  
Nitrophenyl Phosphate ◽  
Hormone Sensitive ◽  
Hydrolysis Of

ABSTRACT A psychrotrophic bacterium producing a cold-adapted lipase upon growth at low temperatures was isolated from Alaskan soil and identified as a Pseudomonas strain. The lipase gene (lipP) was cloned from the strain and sequenced. The amino acid sequence deduced from the nucleotide sequence of the gene (924 bp) corresponded to a protein of 308 amino acid residues with a molecular weight of 33,714. LipP also has consensus motifs conserved in other cold-adapted lipases, i.e., Lipase 2 from AntarcticMoraxella TA144 (G. Feller, M. Thiry, J. L. Arpigny, and C. Gerday, DNA Cell Biol. 10:381–388, 1991) and the mammalian hormone-sensitive lipase (D. Langin, H. Laurell, L. S. Holst, P. Belfrage, and C. Holm, Proc. Natl. Acad. Sci. USA 90:4897–4901, 1993): a pentapeptide, GDSAG, containing the putative active-site serine and an HG dipeptide. LipP was purified from an extract of recombinantEscherichia coli C600 cells harboring a plasmid coding for the lipP gene. The enzyme showed a 1,3-positional specificity toward triolein. p-Nitrophenyl esters of fatty acids with short to medium chains (C4 and C6) served as good substrates. The enzyme was stable between pH 6 and 9, and the optimal pH for the enzymatic hydrolysis of tributyrin was around 8. The activation energies for the hydrolysis ofp-nitrophenyl butyrate and p-nitrophenyl laurate were determined to be 11.2 and 7.7 kcal/mol, respectively, in the temperature range 5 to 35°C. The enzyme was unstable at temperatures higher than 45°C. The Km of the enzyme for p-nitrophenyl butyrate increased with increases in the assay temperature. The enzyme was strongly inhibited by Zn2+, Cu2+, Fe3+, and Hg2+ but was not affected by phenylmethylsulfonyl fluoride and bis-nitrophenyl phosphate. Various water-miscible organic solvents, such as methanol and dimethyl sulfoxide, at concentrations of 0 to 30% (vol/vol) activated the enzyme.

Stimulation of hormone-sensitive lipase activity by contractions in rat skeletal muscle

2000 ◽  
Vol 351 (1) ◽  
pp. 207-214 ◽  
Author(s):  
Jozef LANGFORT ◽  
Thorkil PLOUG ◽  
Jacob IHLEMANN ◽  
Cecilia HOLM ◽  
Henrik GALBO
Keyword(s):  
Skeletal Muscle ◽  
Lipase Activity ◽  
Glycogen Phosphorylase ◽  
Time Course ◽  
Total Activity ◽  
Hormone Sensitive Lipase ◽  
Hormone Sensitive ◽  
Neutral Lipase ◽  
Glycogen Phosphorylase Activity ◽  
Muscle Triglyceride

Because the enzymic regulation of muscle triglyceride breakdown is poorly understood we studied whether neutral lipase in skeletal muscle is activated by contractions. Incubated soleus muscles from 70 g rats were electrically stimulated for 60min. Neutral lipase activity against triacylglycerol increased after 1 and 5min of contractions [0.36±0.02 (basal) versus 0.49±0.05 (1min) and 0.54±0.05 (5min) m-unit·mg of protein-1, means±S.E.M., P < 0.05]. After 10min the neutral lipase activity (0.40±0.05m-unit·mg of protein-1) had decreased to basal values (P > 0.05). The contraction-mediated increase in lipase activity was increased by ≈ 110% when muscle was stimulated in the presence of okadaic acid. Conversely, treatment of muscle homogenate with alkaline phosphatase completely reversed the contraction-mediated lipase activation. Lipase activity did not change during contractions when analysed in the presence of anti-hormone-sensitive-lipase (HSL) antibody [0.17±0.02 (basal) versus 0.21±0.02 (5min) m-unit·mg of protein-1, P > 0.05]. Furthermore, immunoprecipitation with affinity-purified anti-HSL antibody reduced muscle-HSL protein concentration by 81±4% and caused similar reductions in lipase activity against triacylglycerol and in the contraction-induced increase in this activity. Neither prior sympathectomy [0.33±0.02 (basal) versus 0.53±0.06 (5min) m-unit·mg of protein-1, P < 0.05] nor propranolol impaired the lipase response to contractions. Glycogen phosphorylase activity in the absence of AMP increased after 1min [27.3±3.1 versus 8.9±1.8% (activity without AMP/total activity with AMP), P < 0.05] and returned to basal levels after 5min. In conclusion, skeletal-muscle-immunoreactive HSL is transiently stimulated by contractions and the mechanism probably involves phosphorylation. The time course of HSL activation is similar to that of glycogen phosphorylase. Apparently, the two enzymes are regulated in parallel by contraction-induced as well as hormonal mechanisms, allowing simultaneous recruitment of all major extra- and intra-muscular energy stores.

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