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C A Jolly

Publications and source records attributed to C A Jolly.

At least 19 recordsLinked to original sources
PubMed2000

Microsomal fatty acyl-CoA transacylation and hydrolysis: fatty acyl-CoA species dependent modulation by liver fatty acyl-CoA binding proteins.

arachidonoyl-CoA. In summary, the data established for the first time a role for both L-FABP and ACBP in microsomal phosphatidic acid biosynthesis. By preferentially stimulating microsomal transacylation of unsaturated long chain fatty acyl-CoAs while concomitantly exerting their differential protection from microsomal acyl-CoA hydrolase, L-FABP and ACBP can uniquely function in modulating the pattern of fatty acids esterified to phosphatidic acid, the de novo precursor of phospholipids and triacylglycerols. This may explain in part the simultaneous presence of these proteins in cell types involved in fatty acid absorption and lipoprotein secretion.

Acyl Coenzyme A↗
PubMed2000

Reduced food consumption increases water intake and modulates renal aquaporin-1 and -2 expression in autoimmune prone mice.

Aquaporin-1(AQP1) and AQP2 are members of the aquaporin family of cell membrane water channel transport proteins and have been implicated in the regulation of renal water excretion. We have previously shown that calorie restriction (CR) relative to ad libitum (AL) feeding extends lifespan and delays the onset of autoimmune kidney disease in lupus-prone (NZBxNZW)F1 (B/W) mice. To determine if AQP1 and/or AQP2 expression is influenced by CR, mice were fed an AL or CR (40% less food) diet until 4 (young) or 9 (old) months of age when mice were sacrificed. Kidneys were removed and the expression of AQP1 and AQP2 was determined at the protein and mRNA levels using western blotting and RT-PCR respectively. While age did not significantly increase AQP1 expression in the AL groups, CR did increase both the protein (1.4-fold) and mRNA (2.4-fold) levels. In old mice, AQP1 expression was higher (1.8-fold) in CR compared to the AL group while CR had no effect in young mice. In contrast, AQP2 showed an age related decrease (55%) in the AL groups and an increase in the protein (8.4-fold) and mRNA (1.7-fold) levels in the CR groups. Relative to AL, CR decreased AQP2 expression at the protein (90%) and mRNA (50%) levels in the young mice while an increase at the protein (2.9-fold) and mRNA (1.9-fold) levels was evident in the old mice. Interestingly, a significant increase in water intake per gram body weight was found in both young and old CR fed mice when compared to their AL counterparts which may contribute to the prevention of autoimmune disease with age and differences in longevity. These data show, for the first time, significant age and diet influences in renal AQP1 and AQP2 expression at both protein and mRNA levels in lupus-prone mice.

Age Factors↗
PubMed2000

Sterol carrier protein-2 suppresses microsomal acyl-CoA hydrolysis.

Although sterol carrier protein 2 (SCP-2) has long been regarded primarily as a sterol transfer protein, its actual physiological function is not known. The recent discovery that SCP-2 binds long chain fatty acyl-CoAs (LCFA-CoAs) with high affinity suggests additional roles for SCP-2 in cellular utilization of LCFA-CoAs for synthesis of glycerides and cholesterol esters. Concomitant to these anabolic pathways, LCFA-CoAs are also degraded by cellular hydrolases. The purpose of the work presented herein was to determine if SCP-2 altered the aqueous pool of LCFA-CoA by (i) extracting LCFA-CoA from microsomal membranes, and (ii) protecting LCFA-CoA from microsomal hydrolase activity. The data demonstrated for the first time that SCP-2 increases the aqueous pool of oleoyl-CoA by increasing the aqueous/membrane distribution oleoyl-CoA by 2.4-fold. In addition, SCP-2 inhibited the hydrolysis of oleoyl-CoA by microsomal acyl-CoA hydrolase 1.6-2.4 fold, depending on the concentration of oleoyl-CoA. By simultaneously extracting LCFA-CoA from membranes and inhibiting LCFA-CoA degradation SCP-2 may potentiate LCFA-CoA transacylation and modulate the role of LCFA-CoAs as intracellular signaling molecules.

Acyl Coenzyme A↗
PubMed1999

Calorie restriction modulates Th-1 and Th-2 cytokine-induced immunoglobulin secretion in young and old C57BL/6 cultured submandibular glands.

Immunoglobulin production by the salivary gland plays an important role in oral and upper respiratory tract immunity. Age and/or disease may compromise salivary gland function. In order to gain insight into the role of calorie restriction (CR) on immunoglobulin (Ig) production, we determined the effect of ad libitum (AL) feeding and CR in young (3 months) and old (18-24 months) C57BL/6 mouse submandibular glands (SM). The SM tissues were fragmented and cultured in the absence (control) or presence of either Th-1 cytokines, such as interleukin-2 (IL-2) and interferon-gamma (IFN-gamma), or Th-2 cytokines, e.g. IL-4 and IL-5, for seven days. Culture supernatants were then analyzed for immunoglobulin A (IgA), IgM, and IgG2a levels by ELISA. Aging increased basal (control) IgA and IgM production by 3.1-and 3.7-fold, respectively, in AL mice. CR prevented the age-dependent rise of both IgA and IgM, maintaining levels equal to those of young AL mice. Interestingly, age resulted in a decrease of Th-1 cytokine-induced IgA and IgM, and increased IgG2a secretion in AL mice, while Th-2 cytokines did not appear to have an age effect. In general, CR suppressed Ig production induced by both Th-1 and Th-2 cytokines in young mice. In contrast, CR in old mice resulted in enhanced IgA and IgM production to levels similar to those in their young counterparts, while IgG2a was predominantly suppressed by Th-1 and not Th-2 cytokines. The data presented herein show, for the first time, the ability of CR to offset age-induced changes in submandibular gland Ig production, which may play a role in maintaining mucosal immune function, including proper oral health.

Aging↗
PubMed1999

Diet modulates Th-1 and Th-2 cytokine production in the peripheral blood of lupus-prone mice.

Calorie restriction or fish oil extends life span. To investigate the potential mechanism(s) involved, young (4-month) and old (9-month) NZB x NZW(F1) mice were fed 5% (w/w) corn oil (CA) or fish oil (FA) ad libitum or 40% restricted (CR and FR, respectively). Peripheral blood T-lymphocytes were analyzed for Th-1 (IL-2, IFN-gamma) and Th-2 (IL-5, IL-10) production. CR and FA partially blunted while FR completely abolished the decline in aged CD4+ T lymphocytes. In contrast, both CR and FR abolished the decline in CD8+ T lymphocytes with age, while FA had no effect. In aged mice, both CR and FR blunted the increase in Th-1 (IL-2, IFN-gamma) cytokine production, while FA was only partially effective. Only FR completely blunted the age-related increase in Th-2 (IL-5, IL-10) cytokine production. These data suggest that FR delays the onset of autoimmune kidney disease by suppressing both Th-1 and Th-2 cytokine production.

Aging↗
PubMed1999

Dietary protein or arginine deficiency impairs constitutive and inducible nitric oxide synthesis by young rats.

Effects of dietary protein or arginine deficiency on constitutive and lipopolysaccharide (LPS)-induced nitric oxide (NO) synthesis were determined in young rats by quantifying urinary nitrate excretion. In Experiment 1, 30-d-old rats (n = 16) were divided randomly into two groups (n = 8/group) and pair-fed on the basis of body weight semipurified isocaloric diets containing 20 or 5% casein. In Experiment 2, 30-d-old rats (n = 24) were divided randomly into three groups (n = 8) and pair-fed on the basis of body weight purified isonitrogenous and isocaloric diets (composed of amino acids) containing 0.0, 0.3 or 1.0% L-arginine. In both experiments, daily collection of urine was initiated 10 d after the start of pair-feeding. On d 17 after the pair-feeding was initiated, LPS (1 mg/kg body wt) was injected intraperitoneally into rats, and urine was collected daily for an additional 7 d. In Experiments 3 and 4, activities of constitutive and inducible NO synthases were measured in macrophages and various tissues from protein- or arginine-deficient rats (n = 6). Body weight was lower in rats fed the 5% casein diet or the 0.0 and 0.3% arginine diets than in those fed 20% casein or 1% arginine, respectively. Dietary protein or arginine deficiency decreased serum concentrations of arginine and urinary nitrate excretion before and after LPS treatment, indicating impaired constitutive and inducible NO synthesis. Protein malnutrition reduced constitutive and inducible NO synthase activities in brain, heart, jejunum, lung, skeletal muscle and spleen, and inducible NO synthase activity in macrophages. Because NO is a mediator of the immune response and is the endothelium-dependent relaxing factor, impaired NO synthesis may help explain immunodeficiency and cardiovascular dysfunction in protein- or arginine-deficient subjects.

Amino Acids↗
PubMed1998

Differential influence of rat liver fatty acid binding protein isoforms on phospholipid fatty acid composition: phosphatidic acid biosynthesis and phospholipid fatty acid remodeling.

The ability of two rat liver fatty acid binding protein (L-FABP) isoforms to influence microsomal phosphatidic acid biosynthesis, a key intermediate in glycerolipid formation, and phospholipid fatty acid remodeling was examined in vitro. Isoform I enhanced microsomal incorporation of [1-14C]-oleoyl-CoA into phosphatidic acid 7-fold while isoform II had no effect relative to basal. In contrast, isoform II enhanced microsomal incorporation of [1-14C]-palmitoyl-CoA into phosphatidic acid 4-fold while isoform I had no effect. These results suggest that each L-FABP isoform selectively utilized different acyl-CoAs for glycerol-3-phosphate esterification. Both isoforms stimulated phosphatidic acid formation by increasing glycerol-3-phosphate acyltransferase activity, not by increasing lysophosphatidic acid acyltransferase activity. Furthermore, the effects of L-FABP on phosphatidic acid biosynthesis could not be correlated with protection from acyl-CoA hydrolysis. L-FABP isoforms also influenced phospholipid fatty acid remodeling in a phospholipid-dependent manner. Isoform I preferentially enhanced oleate and palmitate esterification into phosphatidylethanol-amine, while isoform II stimulated esterification into phosphatidylcholine, phosphatidylserine and sphingomyelin. Taken together, these data demonstrated a unique role of each L-FABP isoform in modulating microsomally derived phospholipid fatty acid composition. (c) 1998 Elsevier Science B.V.

Acyl Coenzyme A↗
PubMed1998

Structure and function of normal and transformed murine acyl-CoA binding proteins.

Acyl-CoA binding protein (ACBP) is a ubiquitous cytosolic protein found in high levels in tumorigenic cells. However, the molecular basis for the elevated levels of ACBP in malignant cells, ligand binding characteristics, and function in microsomal phospholipid synthesis have not been resolved. To address whether tumorigenic ACBP differs from the native protein, ACBP was purified from LM cells, a tumorigenic subline of mouse L-929 fibroblasts, and its primary structure was examined by delayed-extraction MALDI-linear TOF mass spectrometry. Proteolytic digestion and peptide sequence analysis confirmed that ACBP from LM cells was identical to native mouse ACBP (based on cDNA-derived amino acid sequence) with no amino acid substitutions, deletions, or posttranslational modifications. A fluorescent binding assay revealed that mouse ACBP bound cis-parinaroyl-CoA with high affinity, Kd 7.6 +/- 2.3 nM, at a single binding site. Furthermore, mouse ACBP enhanced microsomal phosphatidic acid formation from oleoyl-CoA 2.3-fold. Mouse ACBP also inhibited microsomal phospholipid acyl chain remodeling of choline-containing phospholipids, phosphatidylcholine and sphingomyelin, by 50 and 64%, respectively. These effects were specific compared to those of native rat liver or recombinant rat ACBP. Mouse and rat ACBPs differed by three amino acid substitutions at positions 4, 68, and 78. Although these small differences in amino acid sequence did not alter binding affinity for cis-parinaroyl-CoA, rat liver ACBP stimulated utilization of oleoyl-CoA 3.8-fold by microsomal glycerol-3-phosphate acyltransferase, significantly higher than that observed with mouse ACBP, but did not alter microsomal phospholipid acyl chain remodeling from oleoyl-CoA. In addition, these ACBPs protected oleoyl-CoA against hydrolysis. Finally, both mouse and rat ACBP shifted the incorporation of oleoyl-CoA from microsomal phospholipid acyl chain remodeling to phosphatidic acid biosynthesis. These data for the first time show a role for ACBP in stimulating microsomal phosphatidic acid biosynthesis and acyl chain remodeling in vitro. While ACBP from tumorigenic cells did not differ from normal, ACBPs from different murine species displayed subtle differences in their effects on microsomal phospholipid metabolism in vitro.

Acyl Coenzyme A↗
PubMed1998

Fatty acid binding protein isoforms: structure and function.

Although structural aspects of cytosolic fatty acid binding proteins (FABPs) in mammalian tissues are now well understood, significant advances regarding the physiological function(s) of these proteins have been slow in forthcoming. Part of the difficulty lies in the complexity of the multigene FABP family with nearly twenty identified members. Furthermore, isoelectric focusing and ion exchange chromatography operationally resolve many of the mammalian native FABPs into putative isoforms. However, a more classical biochemical definition of an isoform, i.e. proteins differing by a single amino acid, suggests that the operational definition is too broad. Because at least one putative heart H-FABP isoform, the mammary derived growth inhibitor, was an artifact (Specht et al. (1996) J. Biol. Chem. 271: 1943-49), the ensuing skepticism and confusion cast doubt on the existence of FABP isoforms in general. Yet, increasing data suggest that several FABPs, e.g. human intestinal I-FABP, bovine and mouse heart H-FABP, rabbit myelin P2 protein and bovine liver L-FABP may exist as true isoforms. In contrast, the rat liver L-FABP putative isoforms may actually be due either to bound ligand, post-translational S-thiolation and/or structural conformers. In any case, almost nothing is known regarding possible functions of either the true or putative isoforms in vitro or in vivo. The objective of this article is to critically evaluate which FABPs form biochemically defined or true isoforms versus FABPs that form additional forms, operationally defined as isoforms. In addition, recent developments in the molecular basis for FABP true isoform formation, the processes leading to additional operationally defined putative isoforms and insights into potential function(s) of this unusual aspect of FABP heterogeneity will be examined.

Animals↗
PubMed1998

Effect of dietary n-3 fatty acids on interleukin-2 and interleukin-2 receptor alpha expression in activated murine lymphocytes.

Dietary eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) suppress interleukin-2 (IL-2) secretion and impair T-lymphocyte proliferation. To determine the mechanism of action, mice were fed diets containing either safflower oil (control diet enriched in linoleic acid, 18:2n-6), EPA, DHA or arachidonic acid (20:4n-6). Splenic lymphocytes were isolated and concanavalin A-induced kinetics of IL-2 and IL-2 receptor alpha mRNA expression were determined by relative competitive-PCR. EPA and DHA did not affect IL-2 mRNA expression but suppressed IL-2 receptor alpha mRNA levels. These data show, for the first time, the selective effects of dietary EPA and DHA on T-lymphocyte gene expression.

Animals↗
PubMed1998

The effects of dietary lipids on gene expression and apoptosis.

The beneficial effects of dietary FO with respect to autoimmune disease, CVD and some types of cancer are well established. Studies conducted over the last 10-15 years have established the potent effects of FO on gene expression in the previously mentioned diseases. The effects of dietary FO appear to be selective in nature, with the expression of individual genes simultaneously being increased, decreased or completely unaffected. In order to elucidate the molecular mechanism(s) involved, recent studies have focused on analysing the effects of the long-chain polyunsaturated n-3 fatty acids EPA and DHA which are highly enriched in FO and thought to be the primary mediators of its biological activity. Indeed, it has been found that EPA and DHA appear to both directly and indirectly modulate gene expression in vivo, depending on the gene examined. The direct effects of EPA and DHA are most probably mediated by their ability to bind to positive and/or negative regulatory transcription factors, while the indirect effects appear to be mediated through alterations in the generation of intracellular lipid second messengers (e.g. diacylglycerol and ceramide). Future studies need to be focused on further elucidation of the inter- and intracellular signalling events mediated by dietary n-3 fatty acids. Understanding the molecular mechanism(s) modified by dietary FO will ultimately lead to improved dietary strategies to aid in the prevention of autoimmune disease, CVD and/or certain types of cancer.

Animals↗
PubMed1997

Fatty acid binding protein: stimulation of microsomal phosphatidic acid formation.

The effect of fatty acid binding proteins (FABPs) on two key steps of microsomal phosphatidic acid formation was examined. Rat liver microsomes were purified by size-exclusion chromatography to remove endogenous cytosolic fatty acid and fatty acyl-CoA binding proteins while recombinant FABPs were used to avoid cross-contamination with such proteins from native tissue. Neither rat liver (L-FABP) nor rat intestinal fatty acid binding protein (I-FABP) stimulated liver microsomal fatty acyl-CoA synthase. In contrast, L-FABP and I-FABP enhanced microsomal conversion of [14C]oleoyl-CoA and glycerol 3-phosphate to [14C]phosphatidic acid by 18- and 7-fold, respectively. The mechanism for this stimulation, especially by I-FABP, is not known. However, several observations presented here suggest that, like L-FABP, I-FABP may interact with fatty acyl-CoA and thereby stimulate enzyme activity. First, I-FABP decreased microsomal membrane-bound oleoyl-CoA. Second, oleoyl-CoA displaced I-FABP bound fluorescent fatty acid, cis-parinaric acid, with Ki of 5.3 microM and 1.1 sites. Third, oleoyl-CoA decreased I-FABP tryptophan fluorescence with a Kd of 4.2 microM. Fourth, oleoyl-CoA red shifted emission spectra of acrylodated I-FABP, a sensitive marker of I-FABP interactions with ligands. In summary, the results demonstrate for the first time that both L-FABP and I-FABP stimulate liver microsomal phosphatidic acid formation by enhancing synthesis of phosphatidate from fatty acyl-CoA and glycerol 3-phosphate.

Acyl Coenzyme A↗
PubMed1997

The sterol carrier protein-2 fatty acid binding site: an NMR, circular dichroic, and fluorescence spectroscopic determination.

The interaction and orientation of fatty acids with recombinant human sterol carrier protein-2 (SCP-2) were examined by nuclear magnetic resonance (NMR), circular dichroism (CD), and fluorescence techniques. 13C-NMR spectroscopy of stearic acid and oleic acid as well as fluorescence spectroscopy of cis-parinaric acid demonstrated that SCP-2 bound naturally occurring fatty acids with near 1:1 stoichiometry. Several findings indicated that the fatty acid was oriented in the binding site with its methyl end buried in the protein interior and its carboxylate exposed at the surface: the chemical shift of bound [18-13C]-stearate; dicarboxylic/monocarboxylic acid cis-parinaric acid displacement; complete ionization of the carboxylate group of SCP-2 bound [1-13C]stearate at neutral pH; lack of electrostatic interactions between 13C-fatty acids with SCP-2 cationic residues: pH titratability of the SCP-2 bound [1-13C]stearate carboxylate group. SCP-2 did not undergo global structural changes upon ligand binding or pH decrease as indicated by the absence of significant changes in NMR and only small alterations in time resolved fluorescence parameters. However, SCP-2 did undergo secondary structural changes detected by CD in the pH range 5-6. While these changes in secondary structure did not alter the fatty acid:SCP-2 binding stoichiometry, the affinity for fatty acid was increased severalfold at lower pH. In summary, 13C-NMR, CD, and fluorescence spectroscopy provided a detailed understanding of the interaction of fatty acids with SCP-2 and further showed for the first time the orientation of the fatty acid within the binding site. The pH-induced changes in SCP-2 secondary structure and ligand binding activity may be important to the mechanism whereby this protein interacts with membrane surfaces to enhance lipid binding/transfer.

Binding Sites↗
PubMed1997

Dietary (n-3) polyunsaturated fatty acids suppress murine lymphoproliferation, interleukin-2 secretion, and the formation of diacylglycerol and ceramide.

Elucidation of the mechanism(s) by which dietary fish oil, enriched in eicosapentaenoic acid (EPA, 20:5(n-3)] and docosahexaenoic acid [DHA, 22:6(n-3)], suppresses the inflammatory process is essential in maximizing this potentially therapeutic effect. Murine T-lymphocyte function and signal transduction were examined in response to a low fat, short term diet enriched in highly purified EPA or DHA ethyl esters. For 10 d, mice were fed comparable diets containing either 3% safflower oil ethyl esters (SAF), 2% SAF + 1% arachidonic acid triglyceride (AA), 2% SAF + 1% EPA, or 2% SAF + 1% DHA. Concanavalin A-induced T-lymphocyte proliferation in splenocyte cultures was significantly suppressed by dietary EPA and DHA while AA had no effect relative to the SAF control. The suppressed proliferative response in EPA- and DHA-fed mice was preceded temporally by a significant reduction in IL-2 secretion. Kinetics of mitogen-induced diacyl-sn-glycerol (DAG) and ceramide production did not differ significantly between SAF and AA diet groups. In contrast, DAG production was significantly suppressed in EP- and DHA-fed mice relative to the SAF and AA groups. The reduced DAG mass was paralleled by reduced ceramide mass following EPA and DHA feeding compared to the SAF and AA groups. Thus, low dose, short term dietary exposure to highly purified EPA or DHA appears to suppress mitogen-induced T-lymphocyte proliferation by inhibiting IL-2 secretion, and these events are accompanied by reductions in the production of essential lipid second messengers, DAG and ceramide.

Animals↗
PubMed1996

Alteration of glycerolipid and sphingolipid-derived second messenger kinetics in ras transformed 3T3 cells.

The effect of ras transformation (rasB fibroblasts) on basal and serum-stimulated diacylglycerol (DAG) composition and mass was examined over time with respect to changes in membrane phospholipid composition and ceramide mass. RasB cells vs. nontransformed control cells (rasD and NR6) had chronically elevated DAG levels (up to 240 min) following serum stimulation, indicating a defect in the recovery phase of the intracellular DAG pulse. Ras transformation also had a dramatic effect on DAG composition. Molecular species analysis revealed that DAG from unstimulated rasB cells was enriched in the delta 9 desaturase fatty acyl species (monoenoate 18:1(n - 7) and 18:1(n - 9)), and depleted in arachidonic acid (20:4(n - 6)). With the exception of glycerophosphoinositol (GPI), DAG remodeling paralleled the compositional alterations in individual phospholipid classes. Importantly, ras transformation altered the fatty acyl composition of sphingomyelin, a precursor to the ceramide second messenger. With the addition of serum, control cells (rasD) had a progressive increase in ceramide mass with levels approximately 5-fold higher by 240 min. In contrast, ceramide levels did not increase in rasB cells at either 4 or 240 min. These results demonstrate that ras-oncogene, in addition to its effects on DAG metabolism, can also abolish the cellular increase in ceramide mass in response to serum stimulation. Since DAG and ceramide may have opposing biological functions, the prolonged elevation of DAG and the suppression of ceramide levels would be consistent with an enhanced proliferative capacity.

3T3 Cells↗
PubMed1996

Diacylglycerol and ceramide kinetics in primary cultures of activated T-lymphocytes.

T cell activation results in the generation of diacylglycerol (DAG), the physiological activator of protein kinase C. Recently, ceramide, a bioactive lipid intracellular second messenger, has been shown to play a positive role in T cell proliferation. Most studies examining mitogen induction of DAG and ceramide in T cells have been conducted in cell lines over short periods of time (0-30 min) relative to the 2-3-h time frame required for commitment to proliferation. Therefore, we examined T cell mitogen-induced DAG and ceramide kinetics under physiologically relevant conditions during the initial 2 h of culture. Freshly isolated murine splenic lymphocytes were stimulated with the T cell-specific mitogen, concanavalin A (Con A). Our results show that Con A induced a multiphasic DAG response with significant peaks in DAG mass occurring at 2, 20 and 120 min. Concomitantly, ceramide mass was significantly increased 2 min following Con A addition and remained elevated until 120 min. Addition of C8-ceramide (10 microM) to lymphocyte cultures significantly enhanced mitogen-induced proliferation. These results demonstrate that DAG is continuously produced by activated T lymphocytes in a multiphasic fashion, and that ceramide is a positive effector molecule with respect to murine T cell proliferation. These results establish a foundation for further examination of the relationship between DAG, ceramide and T cell activation.

Animals↗