A xanthene derivative, DS20060511, attenuates glucose intolerance by inducing skeletal muscle-specific GLUT4 translocation in mice.

Reduced glucose uptake into the skeletal muscle is an important pathophysiological abnormality in type 2 diabetes, and is caused by impaired translocation of glucose transporter 4 (GLUT4) to the skeletal muscle cell surface. Here, we show a xanthene derivative, DS20060511, induces GLUT4 translocation to the skeletal muscle cell surface, thereby stimulating glucose uptake into the tissue. DS20060511 induced GLUT4 translocation and stimulated glucose uptake into differentiated L6-myotubes and into the skeletal muscles in mice. These effects were completely abolished in GLUT4 knockout mice. Induction of GLUT4 translocation by DS20060511 was independent of the insulin signaling pathways including IRS1-Akt-AS160 phosphorylation and IRS1-Rac1-actin polymerization, eNOS pathway, and AMPK pathway. Acute and chronic DS20060511 treatment attenuated the glucose intolerance in obese diabetic mice. Taken together, DS20060511 acts as a skeletal muscle-specific GLUT4 translocation enhancer to facilitate glucose uptake. Further studies of DS20060511 may pave the way for the development of novel antidiabetic medicines.

Arylpiperazines as fatty acid transport protein 1 (FATP1) inhibitors with improved potency and pharmacokinetic properties.

The discovery and optimization of a novel series of FATP1 inhibitors are described. Through the derivatization process, arylpiperazine derivatives 5k and 12a were identified as possessing potent in vitro activity against human and mouse FATP1s as well as excellent pharmacokinetic properties. In vivo evaluation of triglyceride accumulation in the liver, white gastrocnemius muscle and soleus is also described.

Discovery and optimization of novel fatty acid transport protein 1 (FATP1) inhibitors.

The discovery, optimization and structure-activity relationship of novel FATP1 inhibitors have been described. The detailed SAR studies of each moiety of the inhibitors combined with metabolite analysis led to the identification of the potent inhibitors 11p and 11q with improved blood stability.

A cardiac myosin light chain kinase regulates sarcomere assembly in the vertebrate heart.

Marked sarcomere disorganization is a well-documented characteristic of cardiomyocytes in the failing human myocardium. Myosin regulatory light chain 2, ventricular/cardiac muscle isoform (MLC2v), which is involved in the development of human cardiomyopathy, is an important structural protein that affects physiologic cardiac sarcomere formation and heart development. Integrated cDNA expression analysis of failing human myocardia uncovered a novel protein kinase, cardiac-specific myosin light chain kinase (cardiac-MLCK), which acts on MLC2v. Expression levels of cardiac-MLCK were well correlated with the pulmonary arterial pressure of patients with heart failure. In cultured cardiomyocytes, knockdown of cardiac-MLCK by specific siRNAs decreased MLC2v phosphorylation and impaired epinephrine-induced activation of sarcomere reassembly. To further clarify the physiologic roles of cardiac-MLCK in vivo, we cloned the zebrafish ortholog z-cardiac-MLCK. Knockdown of z-cardiac-MLCK expression using morpholino antisense oligonucleotides resulted in dilated cardiac ventricles and immature sarcomere structures. These results suggest a significant role for cardiac-MLCK in cardiogenesis.

Neurotrophin signaling through the p75 receptor is deficient in traf6-/- mice.

Activation of the neurotrophin receptor p75 has been shown to elicit opposing cellular signals. Depending on the context of the cell, p75 will either promote survival or induce apoptosis after neurotrophin stimulation. p75-induced apoptosis occurs through activation of c-Jun N-terminal kinase (JNK), whereas the survival signal is mediated by nuclear factor kappaB (NFkappaB). The receptor proximal signals that produce these responses are unknown, although several molecules have been identified that associate with the intracellular domain of p75. One such interactor, TRAF6, a member of the tumor necrosis factor receptor-associated factor family, has been implicated in p75 signaling. To assess the role of TRAF6 in p75 signaling, we analyzed mice with this gene deleted. In Schwann cells isolated from traf6+/+ animals, NGF elicited an 80% increase in transcription of an NFkappaB reporter; however, in traf6-/- cells, the NGF response was abrogated. Similarly, NGF activation of JNK was not apparent in Schwann cells from mice lacking traf6. Deficiencies in p75 signaling in traf6-/- animals resulted in a loss of p75-mediated apoptosis. In sympathetic neurons cultured from traf6+/+ superior cervical ganglia (SCGs), there was an increase in JNK activation and apoptosis after BDNF binding to p75; however, traf6-/- neurons did not respond. In vivo during naturally occurring cell death, there was a 55.6% reduction in TUNEL (terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end labeling)-positive cells in the SCG of postnatal day 4 traf6-/- animals relative to traf6+/+ littermates. These results indicate that TRAF6 plays an essential role in mediating p75 signal transduction and induction of apoptosis.

Circuit training for elderly patients with chronic obstructive pulmonary disease: a preliminary study.

To examine the efficacy of the circuit training in elderly patients with chronic obstructive pulmonary disease (COPD), we evaluated muscle forces of the upper and lower extremities and respiratory muscles, exercise tolerance and quality of life (QOL) before and after the circuit training in 10 male patients with mild to severe COPD. The circuit training improved muscle forces of the upper and lower extremities and abdominal muscles (P < 0.05), and 6 min walking distance (P < 0.05). Emotional function and mastery in the Chronic Respiratory Disease Questionnaire scores (P < 0.05) were also improved after the circuit training. The circuit training designed in the present study was effective to improve the QOL in elderly COPD patients.

Traf6 is essential for murine tooth cusp morphogenesis.

Ectodermal appendages such as skin, hair, teeth, and sweat glands are affected in patients with hypohidrotic (anhydrotic) ectodermal dysplasia (HED). It has been established that mutations in the tumor necrosis factor (TNF) superfamily of molecules, i.e., ectodysplasin (EDA), EDA receptor (EDAR), and EDAR-associated death domain (EDARADD; the intracellular adaptor for EDAR), are responsible for several forms of HED in humans and mice. We show here by in situ hybridisation that another TNF family (orphan) receptor, TROY (also known TAJ, TAJ-alpha, TRADE, and TNFRSF19), is strongly coexpressed with Edar in the epithelial enamel knot signalling centres that are believe to regulate cuspal morphogenesis during murine tooth development. Traf6 is known to function as an intracellular adaptor protein for Troy and examination of Traf6 mutant mice revealed abnormalities in molar teeth that are similar but more severe than those produced by mutations in Eda signalling molecules. This finding suggests that, in additional to ectodysplasin, another TNF pathway involving Troy/Traf6 is involved in molar tooth cusp formation and identifies an essential role for a Traf in tooth development. Developmental Dynamics 229:131-135, 2004.

Plasma orexin-A levels and body composition in COPD.

STUDY OBJECTIVE: To study the role of orexins in regulating body composition in patients with COPD. DESIGN: Prospective study. PATIENTS AND MEASUREMENTS: We measured the plasma concentration of orexin-A in 20 patients with COPD and compared the results to those obtained from 10 age-matched control subjects. Patients with COPD were classified into two groups based on their body mass index (BMI): a normal weight (NW) group (BMI > 20) and an underweight (UW) group (BMI < 20). RESULTS: The plasma orexin-A level was significantly lower in patients with COPD than in control subjects. In patients with COPD, the level was significantly lower in the UW group than in the NW group. Plasma orexin-A levels significantly correlated with BMI and fat mass values, but there was no significant relationship between plasma orexin-A levels and the fat-free mass of patients with COPD. CONCLUSION: These results suggest that orexin-A levels are altered with weight loss and changes in body composition in patients with COPD.

Different cytokines induce surface lymphotoxin-alphabeta on IL-7 receptor-alpha cells that differentially engender lymph nodes and Peyer's patches.

The formation of lymph nodes (LN) and Peyer's patches (PP) can be distinguished by the requirement of RANK for LN but not IL-7R(alpha), which is essential for PP development. However, lymphotoxin-alphabeta (LT(alpha)beta) signaling is required for both organs. The cellular basis underlying this dichotomy was revealed by the finding that the fetal IL-7R(alpha)(+) population responded equally well to IL-7 and RANKL to express LT(alpha)beta. IL-7R(alpha)(+) cells harvested from TRAF6(-/-) embryos expressed LTalphabeta in response to IL-7 but not RANKL, demonstrating that the RANK-TRAF6 signaling pathway regulates LT(alpha)beta expression in LN but not in PP. Soluble IL-7 administered to TRAF6(-/-) embryos was sufficient to restore LN genesis indicating the functional similarities of the IL-7R(alpha)(+) inducer cells for LN and PP genesis.

Age-related changes in plasma orexin-A concentrations.

To study the effect of aging on orexin-A, we measured plasma orexin-A concentrations in 82 healthy volunteers (55 men and 27 women) over a wide range of ages (mean 50.2 +/- 13.9 years, ranging from 23 to 79 years). Correlation analyses revealed that plasma orexin-A concentrations correlated with age (r = 0.50, P < 0.01). When comparing three age groups, it appeared that the concentrations in the group of more than 60 years were significantly higher than those in the group of less than 39 years in both genders (P < 0.05). These findings suggest that orexin-A could be involved in aging in a healthy population.

Mucosal addressin cell adhesion molecule 1 plays an unexpected role in the development of mouse guard hair.

The first wave of coat hair development is initiated around embryonic day 14 in the mouse. Whereas ectodysplasin and ectodermal dysplasia receptor, tumor necrosis factor and tumor necrosis factor receptor family molecules, respectively, were identified to be signals triggering this process, not much was known regarding their downstream molecular targets. In this report, we show that mucosal addressin cell adhesion molecule 1 and intercellular adhesion molecule 1 are induced in the keratinocytes of the hair placode as a direct consequence of ectodermal dysplasia receptor signal, and tumor-necrosis-factor-receptor-associated factor 6 is involved in this mucosal addressin cell adhesion molecule 1 expression. Experiments using an in vitro culture of skin fragments demonstrated that ectodermal-dysplasia-receptor-induced mucosal addressin cell adhesion molecule 1 expression occurs at the initial phase of follicle development before involvement of Sonic hedgehog signal. Follicle development in this culture was also suppressed to some extent, though not completely, by addition of soluble mucosal addressin cell adhesion molecule 1/IgG-Fc chimeric protein, whereas monoclonal antibody that can inhibit mucosal addressin cell adhesion molecule 1 interaction with integrin alpha4beta7 had no effect on this process. These results demonstrated for the first time that the structural proteins, mucosal addressin cell adhesion molecule 1 and intercellular adhesion molecule 1, are induced by ectodermal dysplasia receptor signal and suggested the potential involvement of mucosal addressin cell adhesion molecule 1 in the morphogenesis of follicular keratinocytes.

TRAF6-deficient mice display hypohidrotic ectodermal dysplasia.

Tumor necrosis factor receptor (TNFR)-associated factor 6 (TRAF6) is an adapter protein that links signals from members of the TNFR superfamily and Toll/IL-1 receptor family to activation of transcription factors NFkappaB and AP-1. Analysis of TRAF6-deficient mice revealed that TRAF6 is essential for normal bone formation and establishment of immune and inflammatory systems. Here we report that TRAF6 deficiency results in defective development of epidermal appendixes, including guard hair follicles, sweat glands, sebaceous glands of back skin, and modified sebaceous glands such as meibomian glands, anal glands, and preputial glands. Except the sebaceous gland impairment, these abnormal phenotypes are identical to those observed in Tabby (Ta), downless (dl), and crinkled (cr) mice, which are models of hypohidrotic (anhidrotic) ectodermal dysplasia in human. beta-catenin and mucosal addressin cell adhesion molecule-1, an early marker of developing guard-hair follicles is absent in the skin of TRAF6-deficient embryos. Thus, TRAF6 is essential for development of epidermal appendixes. TRAF6 does not associate with the cytoplasmic tail of the dl protein (DL)/ectodysplasin receptor (EDAR) receptor, which, when mutated, results in hypohidrotic (anhidrotic) ectodermal dysplasia. However, TRAF6 associates with X-linked ectodysplasin-A2 receptor (XEDAR) and TNFR super family expressed on the mouse embryo (TROY/toxicity and JNK inducer (TAJ), which are EDAR-related members of the TNFR superfamily that are expressed at high level in epidermal appendixes. Furthermore, TRAF6 is essential for the XEDAR-mediated NFkappaB activation. Our results suggest that TRAF6 may transduce signals emanating from XEDAR or TROY/TAJ that are associated with development of epidermal appendixes.