Linda J. Kelly

Peroxisome Proliferator-Activated Receptors γ and α Mediate in Vivo Regulation of Uncoupling Protein (UCP-1, UCP-2, UCP-3) Gene Expression

A role for peroxisome proliferator-activated receptors, PPAR gamma and PPAR alpha, as regulators of energy homeostasis and lipid metabolism, has been suggested. Recently, three distinct uncoupling protein isoforms, UCP-1, UCP-2, and UCP-3, have also been identified and implicated as mediators of thermogenesis. Here, we examined whether in vivo PPAR gamma or PPAR alpha activation regulates the expression of all three UCP isoforms. Rats or lean and db/db mice were treated with PPAR gamma [thiazolidinedione (TZD)] or PPAR alpha (WY-14643) agonists, followed by measurement of messenger RNAs (mRNAs) for UCP-1, UCP-2, and UCP-3 in selected tissues where they are expressed. TZD treatment (AD 5075 at 5 mg/kg x day) of rats (14 days) increased brown adipose tissue (BAT) depot size and induced the expression of each UCP mRNA (3x control levels for UCP-1 and UCP-2, 2.5x control for UCP-3). In contrast, UCP-2 and UCP-3 mRNA levels were not affected in white adipose tissue or skeletal muscle. Chronic (30 days) low-dose (0.3 mg/kg x day) TZD treatment induced UCP-1 mRNA and protein in BAT (2.5x control). In contrast, chronic TZD treatment (30 mg/kg x day) suppressed UCP-1 mRNA (>80%) and protein (50%) expression in BAT. This was associated with further induction of UCP-2 expression (>10-fold) and an increase in the size of lipid vacuoles, a decrease in the number of lipid vacuoles in each adipocyte, and an increase in the size of the adipocytes. TZD treatment of db/db mice (BRL 49653 at 10 mg/kg x day for 10 days) also induced UCP-1 and UCP-3 (but not UCP-2) expression in BAT. PPAR alpha is present in BAT, as well as liver. Treatment of rats or db/db mice with WY-14643 did not affect expression of UCP-1, -2, or -3 in BAT. Hepatic UCP-2 mRNA was increased (4x control level) in db/db and lean mice, although this effect was not observed in rats. Thus, in vivo PPAR gamma activation can induce expression of UCP-1, -2, and -3 in BAT; whereas chronic-intense PPAR gamma activation may cause BAT to assume white adipose tissue-like phenotype with increased UCP-2 levels. PPAR alpha activation in mice is sufficient to induce liver UCP-2 expression.

A Novel Liver X Receptor Agonist Establishes Species Differences in the Regulation of Cholesterol 7α-Hydroxylase (CYP7a)

The liver X receptors, LXRα and LXRβ, are members of the nuclear receptor superfamily. Originally identified as orphans, both receptor subtypes have since been shown to be activated by naturally occurring oxysterols. LXRα knockout mice fail to regulate cyp7a mRNA levels upon cholesterol feeding, implicating the role of this receptor in cholesterol homeostasis. LXR activation also induces the expression of the lipid pump involved in cholesterol efflux, the gene encoding ATP binding cassette protein A1 (ABCA1). Therefore, LXR is believed to be a sensor of cholesterol levels and a potential therapeutic target for atherosclerosis. Here we describe a synthetic molecule named F3MethylAA [3-chloro-4-(3-(7-propyl-3-trifluoromethyl-6-(4,5)-isoxazolyl)propylthio)-phenyl acetic acid] that is more potent than 22(R)-hydroxycholesterol in LXR in vitro assays. F3MethylAA is capable not only of inducing ABCA1 mRNA levels, but also increasing cholesterol efflux from THP-1 macrophages. In rat hepatocytes, F3MethylAA induce...

Disulfide bonds are neither required, present, nor compatible with full activity of human recombinant acidic fibroblast growth factor.

Human acidic fibroblast growth factor (aFGF) is a potent broad-spectrum mitogen that contains three Cys residues within its monomeric structure. We have found that site-directed mutants in which any one of these Cys residues is converted to serine remain highly active, although variably dependent on heparin, so none of the three possible intramolecular disulfide bonds that can be formed are required for mitogenic activity. Furthermore, a dispensable disulfide bond that might stabilize the active conformation is not present since all three Cys residues are accessible to chemical modification in recombinant as well as brain-derived aFGFs. Finally, formation of a disulfide bond between the two Cys residues conserved among all seven known members of the FGF family results in a virtually inactive product that can subsequently be reactivated by reduction. Thus, despite the extracellular function of aFGF, its Cys residues do not form intramolecular disulfide bonds in the active conformation.

Asenapine: Efficacy and safety of 5 and 10 mg bid in a 3-week, randomized, double-blind, placebo-controlled trial in adults with a manic or mixed episode associated with bipolar I disorder

BACKGROUND Asenapine is an atypical antipsychotic for acute treatment of manic or mixed episodes associated with bipolar I disorder in adults. The recommended asenapine starting dose is 10mg bid with the option to reduce the dose to 5mg bid if needed due to adverse effects/tolerability. METHODS Phase IIIb, international, double-blind, fixed-dose, parallel-group, 3-week placebo-controlled trial of asenapine 5 and 10mg bid in adults with an acute bipolar I disorder manic or mixed episode. Primary outcome was difference in asenapine versus placebo in mean change from baseline to day 21 in the Young-Mania Rating Scale (YMRS) total score. Others included difference in asenapine versus placebo in the Clinical Global Impression Scale for Bipolar Severity (CGI-BP-S) and rate of YMRS responders. RESULTS Both asenapine doses were statistically superior to placebo in mean change from baseline to day 21 in YMRS total score (-10.9, -14.4, and -14.9 for placebo, asenapine 5mg bid, 10mg bid, respectively). Both asenapine doses had statistically superior improvement in mean change in CGI-BP-S score at day 21. Neither asenapine dose had significantly more YMRS responders at day 21 than placebo. LIMITATIONS Results may not be generalizable to the entire population with bipolar I disorder owing to strict inclusion criteria. CONCLUSIONS This study evaluated, by a fixed-dose design, the efficacy and safety of asenapine versus placebo in patients with bipolar I disorder. Both asenapine 5 and 10mg bid were efficacious in treating mania associated with bipolar I disorder and were generally well tolerated.

Asenapine for the treatment of adults with an acute exacerbation of schizophrenia: results from a randomized, double-blind, fixed-dose, placebo-controlled trial with olanzapine as an active control.

OBJECTIVE Evaluate the efficacy and safety of asenapine 2.5 mg twice daily (bid; n=97) or 5 mg bid (n=113) versus placebo (n=101) in adults with acute exacerbation of schizophrenia. METHODS Adults with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) schizophrenia diagnosis were randomized to asenapine 2.5 mg bid, 5 mg bid, placebo, or olanzapine 15 mg once daily. The primary objective was to test superiority of asenapine versus placebo as measured by the change from baseline to day 42 in the Positive and Negative Syndrome Scale (PANSS) total score. The key safety objective was to evaluate weight change in asenapine versus olanzapine at day 42. RESULTS The primary efficacy endpoint was met; the difference in least squares mean change from baseline to day 42 in PANSS total score between asenapine 5 mg bid and placebo was -5.5 points (unadjusted 95% CI: -10.1, -1.0; multiplicity adjusted P=0.0356). Neither asenapine 2.5 mg bid nor olanzapine 15mg were superior to placebo. Both asenapine groups demonstrated significantly less weight gain than olanzapine at day 42. Significantly higher incidences of oral hypoesthesia and dysgeusia (combined) for asenapine 2.5 mg bid (5.2% vs 0.0%; P=0.0217) and 5 mg bid (7.1% vs 0.0%; P=0.0033) were observed versus placebo. There were no significant differences between asenapine and placebo for insomnia, extrapyramidal symptoms, akathisia, dizziness, or combination of somnolence/sedation/hypersomnia. CONCLUSION This study supports previous efficacy and safety findings of asenapine; asenapine 5 mg bid is the lowest effective dose in adults with schizophrenia. Asenapine was associated with significantly less weight gain than olanzapine at day 42.

Structure, Homologies and Activities of Acidic Fibroblast Growth Factor

Fibroblast growth factors (FGFS, reviewed by Thomas and Gimenez-Gallego, 1986) are mitogens for a wide variety of cells in culture including not only fibroblasts but also vascular endothelial cells, myoblasts, chondrocytes, osteoblasts and glial cells. In vivo, FGFS have been shown to promote blood vessel growth. Acidic and basic forms of FGFS have been identified, purified and characterized which, although structurally related to each other, are unique gene products. Alternative names for these molecules have been proposed based on their source (retina-derived growth factors, eye-derived growth factors, brain-derived growth factors), target cells (endothelial cell growth factor, astroglial growth factors, prostatropins) and ability to bind to heparin (heparin-binding growth factors). The amino acid sequence, homologies and activities of acidic FGF (aFGF) are reported.