Overexpression of bone morphogenetic protein-3b (BMP-3b) in adipose tissues protects against high-fat diet-induced obesity.

BACKGROUND: Bone morphogenetic protein-3b (BMP-3b) is a member of the transforming growth factor-ß superfamily and has several activities that differ from those of other BMPs. We previously found that BMP-3b is highly expressed in adipocytes, its level is increased during obesity, and it inhibits adipogenesis by suppressing peroxisome proliferator-activated receptor γ (PPARγ) in vitro. However, the function of BMP-3b in adipose tissues in vivo remains unknown. METHODS: To determine the role of BMP-3b overexpression in adipose tissues in vivo, we generated transgenic mice (BMP-3b Tg) by using a conditional overexpression approach in fatty acid-binding protein 4-expressing adipocytes. We examined BMP-3b Tg mice fed a high-fat diet to elucidate the effects of BMP-3b on obesity. Adipocyte function was evaluated as expression of adipogenic and lipogenic markers in adipose tissue. We also performed glucose and insulin tolerance tests (GTT and ITT, respectively), and biochemical analysis of serum and measured energy expenditure by indirect calorimetry. RESULTS: BMP-3b Tg mice fed a high-fat diet showed decreases in weight gain, fat-pad mass and adipocyte area, compared with wild-type mice. The adipose tissues of BMP-3b Tg mice showed downregulated expression of PPARγ and its target gene encoding fatty acid translocase/CD36. In addition, BMP-3b Tg mice had decreased blood glucose levels on GTT and ITT, and their serum leptin levels were decreased and adiponectin concentrations were increased. These changes in BMP-3b Tg mice were accompanied by increased energy expenditure, indicated as increased locomotor activity and oxygen consumption. CONCLUSIONS: These results provide in vivo evidence that BMP-3b regulates adipocyte function to cause an anti-obesity effect.

Identification and characterization of PDGFRα+ mesenchymal progenitors in human skeletal muscle.

Fatty and fibrous connective tissue formation is a hallmark of diseased skeletal muscle and deteriorates muscle function. We previously identified non-myogenic mesenchymal progenitors that contribute to adipogenesis and fibrogenesis in mouse skeletal muscle. In this study, we report the identification and characterization of a human counterpart to these progenitors. By using PDGFRα as a specific marker, mesenchymal progenitors can be identified in the interstitium and isolated from human skeletal muscle. PDGFRα(+) cells represent a cell population distinct from CD56(+) myogenic cells, and adipogenic and fibrogenic potentials were highly enriched in the PDGFRα(+) population. Activation of PDGFRα stimulates proliferation of PDGFRα(+) cells through PI3K-Akt and MEK2-MAPK signaling pathways, and aberrant accumulation of PDGFRα(+) cells was conspicuous in muscles of patients with both genetic and non-genetic muscle diseases. Our results revealed the pathological relevance of PDGFRα(+) mesenchymal progenitors to human muscle diseases and provide a basis for developing therapeutic strategy to treat muscle diseases.

Estimates of genetic relatedness among males in a polygynous wasp.

Cyclical oligogyny is considered to be the mechanism that is most likely to be responsible for stabilizing cooperation in polygynous, epiponine wasps, in which single-queen colonies produce new queens and multiple-queen colonies produce males. In contrast with the number of studies on relatedness among adult females, we know little about relatedness among males in polygynous epiponine wasps. We estimated worker and male relatedness in the Brazilian epiponine wasp Polybia paulista Ihering and found that colonies of P. paulista produced males when they contained multiple queens. Although average relatedness within males did not differ significantly from 0.5, the number of alleles observed suggests that there were more than one queen to produce males in each colony. Our data would be helpful to elucidate dynamics of the male production in a colony of epiponine wasps.

Effect of non-uniform electron energy distribution function on plasma production in large arc driven negative ion source.

Spatially non-uniform electron energy distribution function (EEDF) in an arc driven negative ion source (JAEA 10A negative ion source: 10 A NIS) is calculated numerically by a three-dimensional Monte Carlo kinetic model for electrons to understand spatial distribution of plasma production (such as atomic and ionic hydrogen (H(0)∕H(+)) production) in source chamber. The local EEDFs were directly calculated from electron orbits including electromagnetic effects and elastic∕inelastic collision forces. From the EEDF, spatial distributions of H(0)∕H(+) production rate were obtained. The results suggest that spatial non-uniformity of H(0)∕H(+) productions is enhanced by high energy component of EEDF.

Voltage holding study of 1 MeV accelerator for ITER neutral beam injector.

Voltage holding test on MeV accelerator indicated that sustainable voltage was a half of that of ideal quasi-Rogowski electrode. It was suggested that the emission of the clumps is enhanced by a local electric field concentration, which leads to discharge initiation at lower voltage. To reduce the electric field concentration in the MeV accelerator, gaps between the grid supports were expanded and curvature radii at the support corners were increased. After the modifications, the accelerator succeeded in sustaining -1 MV in vacuum without beam acceleration. However, the beam energy was still limited at a level of 900 keV with a beam current density of 150 A∕m(2) (346 mA) where the 3 × 5 apertures were used. Measurement of the beam profile revealed that deflection of the H(-) ions was large and a part of the H(-) ions was intercepted at the acceleration grid. This causes high heat load on the grids and the breakdowns during beam acceleration. To suppress the direct interception, new grid system was designed with proper aperture displacement based on a 3D beam trajectory analysis. As the result, the beam deflection was compensated and the voltage holding during the beam acceleration was improved. Beam parameter of the MeV accelerator was increased to 980 keV, 185 A∕m(2) (427 mA), which is close to the requirement of ITER accelerator (1 MeV, 200 A∕m(2)).

Acceleration of palatal wound healing in Smad3-deficient mice.

Wound healing is a well-orchestrated complex process leading to the repair of injured tissues. It is suggested that transforming growth factor (TGF)-beta/Smad3 signaling is involved in wound healing. The purpose of this study was to investigate the role of TGF-beta/Smad3 signaling in palatal wound healing in Smad3-deficient (Smad3(-/-)) mice. Histological examination showed that wound closure was accelerated by the proliferation of epithelium and dermal cells in Smad3(-/-) mice compared with wild-type (WT) mice. Macrophage/monocyte infiltration at wounded regions in Smad3(-/-) mice was decreased in parallel with the diminished production of TGF-beta1, monocyte chemoattractant protein-1, and macrophage inflammatory protein-1alpha compared with WT mice. Fibrocytes, expressing hematopoietic surface marker and fibroblast products, were recruited and produced alpha-smooth-muscle actin in WT mice, but were not observed in Smad3(-/-) mice. These results suggest that TGF-beta/Smad3 signaling may play an important role in the regulation of palatal wound healing.

Myostatin inhibition by a follistatin-derived peptide ameliorates the pathophysiology of muscular dystrophy model mice.

Gene-targeted therapies, such as adeno-associated viral vector (AAV)-mediated gene therapy and cell-mediated therapy using myogenic stem cells, are hopeful molecular strategies for muscular dystrophy. In addition, drug therapies based on the pathophysiology of muscular dystrophy patients are desirable. Multidisciplinary approaches to drug design would offer promising therapeutic strategies. Myostatin, a member of the transforming growth factor-beta superfamily, is predominantly produced by skeletal muscle and negatively regulates the growth and differentiation of cells of the skeletal muscle lineage. Myostatin inhibition would increase the skeletal muscle mass and prevent muscle degeneration, regardless of the type of muscular dystrophy. Myostatin inhibitors include myostatin antibodies, myostatin propeptide, follistatin and follistatin-related protein. Although follistatin possesses potent myostatin-inhibiting activity, it works as an efficient inhibitor of activins. Unlike myostatin, activins regulate the growth and differentiation of nearly all cell types, including cells of the gonads, pituitary gland and skeletal muscle. We have developed a myostatin-specific inhibitor derived from follistatin, designated FS I-I. Transgenic mice expressing this myostatin-inhibiting peptide under the control of a skeletal muscle-specific promoter showed increased skeletal muscle mass and strength. mdx mice were crossed with FS I-I transgenic mice and any improvement of the pathological signs was investigated. The resulting mdx/FS I-I mice exhibited increased skeletal muscle mass and reduced cell infiltration in muscles. Muscle strength was also recovered in mdx/FS I-I mice. Our data indicate that myostatin inhibition by this follistatin-derived peptide has therapeutic potential for muscular dystrophy.

Caveolin-3 regulates myostatin signaling. Mini-review.

Caveolins, components of the uncoated invaginations of plasma membrane, regulate signal transduction and vesicular trafflicking. Loss of caveolin-3, resulting from dominant negative mutations of caveolin-3 causes autosomal dominant limb-girdle muscular dystrophy (LGMD) 1C and autosomal dominant rippling muscle disease (AD-RMD). Myostatin, a member of the muscle-specific transforming growth factor (TGF)-beta superfamily, negatively regulates skeletal muscle volume. Herein we review caveolin-3 suppressing of activation of type I myostatin receptor, thereby inhibiting subsequent intracellular signaling. In addition, a mouse model of LGMD1C has shown atrophic myopathy with enhanced myostatin signaling. Myostatin inhibition ameliorates muscular phenotype in the model mouse, accompanied by normalized myostatin signaling. Enhanced myostatin signaling by caveolin-3 mutation in human may contribute to the pathogenesis of LGMD1C. Therefore, myostatin inhibition therapy may be a promising treatment for patients with LGMD1C. More recent studies concerning regulation of TGF-beta superfamily signaling by caveolins have provided new insights into the pathogenesis of several human diseases.

Activin induces long-lasting N-methyl-D-aspartate receptor activation via scaffolding PDZ protein activin receptor interacting protein 1.

Calcium entry into the postsynaptic neuron through N-methyl-D-aspartate-type glutamate receptors (NMDARs) triggers the induction of long-term potentiation (LTP), which is considered to contribute to synaptic plasticity and plays a critical role in behavioral learning. We report here that activin, a member of the transforming growth factor-beta (TGF-beta) superfamily, promotes phosphorylation of NMDARs and increases the Ca2+ influx through these receptors in primary cultured rat hippocampal neurons. This signal transduction occurs in a functional complex of activin receptors, NMDARs, and Src family tyrosine kinases, including Fyn, formed on a multimer of postsynaptic scaffolding postsynaptic density protein 95/Dlg/ZO-1 (PDZ), activin receptor interacting protein 1 (ARIP1). Activin-induced NMDAR activation persists for more than 24 h, which is complimentary to the activation time of NMDARs by brain-derived neurotrophic factor (BDNF). Our results suggest that activin is a unique and powerful potentiator for NMDAR-dependent signaling, which could be involved in the regulatory mechanisms of synaptic plasticity.

Overproduction of the follistatin-related gene protein in the placenta and maternal serum of women with pre-eclampsia.

OBJECTIVE: To characterise the follistatin-related gene (FLRG) in pre-eclampsia, one of the differentially expressed genes in pre-eclamptic placenta. DESIGN AND METHODS: We examined and compared the messenger RNA (mRNA) and protein levels of FLRG in placentas and maternal sera from women with uncomplicated pregnancy, and those with pre-eclampsia using real-time reverse transcription polymerase chain reaction, Western blot, immunohistochemistry, and enzyme-linked immunosorbent assay. SETTING: Antenatal clinics in a teaching hospital. POPULATION: Women with uncomplicated pregnancy (n = 21) and those with pre-eclampsia (n = 21). RESULTS: FLRG mRNA is overexpressed in pre-eclamptic placental tissues (P < 0.01). Upregulated FLRG protein consists of both an immature 28-kDa cellular product and a mature 33-kDa secretory form, which are differentially glycosylated. FLRG is normally produced at its highest levels in endothelial cells and at moderate amounts in syncytiotrophoblast cells, but in pre-eclampsia, the syncytiotrophoblast FLRG levels are dramatically increased. We also determined the maternal serum concentrations of FLRG in our uncomplicated pregnancy subjects and in our pre-eclamptic groups, and found that they are significantly elevated in pre-eclampsia in a similar manner to activin A and inhibin A. However, the increase in FLRG in these cases is independent of activin A or inhibin A, and is associated with low-birthweight outcomes. CONCLUSION: Our current data show the placental and secretory changes of FLRG protein in pre-eclampsia, and also indicate the potential usefulness of FLRG as an additional diagnostic marker for pre-eclampsia.

Nitroglycerin on contractile force in canine cardiac Purkinje fibers.

The objective of this study was to investigate the effects of nitroglycerin (NG) on the contractile force in order to elucidate regulatory roles of cyclic guanosine monophosphate (cGMP) in the bundle of canine cardiac Purkinje fibers. NG suppressed the developed tension in canine Purkinje fibers immersed in normal Tyrode's solution. The contraction was also elicited in the depolarizing solution containing 30 mM K+ by adding isoproterenol (Iso) or tetraethylammonium (TEA). The suppression caused by NG was more marked in fibers in the depolarizing solution treated with TEA than in the depolarizing solution treated with Iso. 8-Bromo-cGMP and sodium nitroprusside had a slight inhibition on the contraction in the fibers. Methylene blue did not affect the decrease in contractile force induced by NG. The weaker inhibition caused by NG on the contraction in the presence of Iso might result from a possible increase in intracellular cAMP levels in the fibers.

Inhibitors of the TGF-beta superfamily and their clinical applications.

The transforming growth factor-beta (TGF-beta) superfamily includes TGF-betas, activin, myostatin and bone morphogenetic proteins. Misregulation of the activity of TGF-beta family members is involved in pathogenesis of cancer, muscular dystrophy, obesity and bone and tooth remodeling. Natural inhibitors for the TGF-beta superfamily regulate fine-tuning of activity of TGF-beta family in vivo. In addition to natural inhibitors for the TGF-beta family, soluble forms of receptors for the TGF-beta family, blocking monoclonal antibodies and small chemical TGF-beta inhibitors have been developed. In this review, we summarize recent advances in our understanding of inhibitors for the TGF-beta superfamily and their medical applications.

Treatment with edaravone improves the survival rate in renal warm ischemia-reperfusion injury using rat model.

Renal ischemia-reperfusion (I/R) injury during renal transplantation is a significant cause of renal dysfunction. The pathological role of free radicals in this process is a major concern. We investigated the effect of a free radical scavenger, edaravone (MCI-186), in renal I/R injury. Male Lewis rats (270 to 320 g) were used for the model. The right kidney was harvested and left renal artery and vein were clamped as laparotomy. The kidney was reperfused after 90 minutes of ischemia. Edaravone (10 mg/kg) was delivered intravenously before ischemia and after reperfusion to prevent the neutrophil activation. In the nontreatment I/R group, no rat survived beyond 4 days. However, in the edaravone I/R treatment group, one among five rats survived more than 7 days. These results suggested that treatment with edaravone ameliorated renal I/R injury, and that the agent has the potential to ameliorate preservation injury in renal transplantation.

Benefical effect of neutrophil elastase inhibitor on renal warm ischemia-reperfusion injury in the rat.

Renal ischemia-reperfusion (I/R) injury is a significant problem in renal transplantation. Neutrophils play an important role in renal I/R injury. Several reports have demonstrated that neutrophil elastase derived from the activated neutrophils might play an important role in this injury. We investigated the effect of a neutrophil elastase inhibitor in renal I/R injury. Male Lewis rats (270-320 g) were used in the model. The right kidney was harvested and the left renal artery and vein were clamped at laparotomy. The kidney was reperfused after 90 minutes of ischemia. Neutrophil elastase inhibitor (ONO-5046: 30 mg/kg) was delivered intravenously before ischemia and after reperfusion to prevent neutrophil activation. In the nontreatment I/R group, no hosts survived 4 days. However, after treatment with neutrophil elastase inhibitor, 3 of 10 rats in the I/R group, survived more than 7 days. These results demonstrated that treatment with neutrophil elastase inhibitor ameliorated renal I/R injury.

Characterization of isoforms of activin receptor-interacting protein 2 that augment activin signaling.

Activin type II receptors (ActRIIs) including ActRIIA and ActRIIB are serine/threonine kinase receptors that form complexes with type I receptors to transmit intracellular signaling of activins, nodal, myostatin and a subset of bone morphogenetic proteins. ActRIIs are unique among serine/threonine kinase receptors in that they associate with proteins having PSD-95, Discs large and ZO-1 (PDZ) domains. In our previous studies, we reported specific interactions of ActRIIs with two independent PDZ proteins named activin receptor-interacting proteins 1 and 2 (ARIP1 and ARIP2). Overexpression of both ARIP1 and ARIP2 reduce activin-induced transcription. Here, we report the isolation of two isoforms of ARIP2 named ARIP2b and 2c. ARIP2, ARIP2b and ARIP2c recognize COOH-terminal residues of ActRIIA that match a PDZ-binding consensus motif. ARIP2 and its isoforms have one PDZ domain in the NH2-terminal region, and interact with ActRIIA. Although PDZ domains containing GLGF motifs of ARIP2b and 2c are identical to that of ARIP2, their COOH-terminal sequences differ from that of ARIP2. Interestingly, unlike ARIP2, overexpression of ARIP2b or 2c did not affect ActRIIA internalization. ARIP2b/2c inhibit inhibitory actions of ARIP2 on activin signaling. ARIP2 is widely distributed in mouse tissues. ARIP2b/2c is expressed in more restricted tissues such as heart, brain, kidneys and liver. Our results indicate that although both ARIP2 and ARIP2b/2c interact with activin receptors, they regulate ActRIIA function in a different manner.

Thromboembolic Events Associated with Coil Protrusion into Parent Arteries after GDC Treatment.

SUMMARY: Aneurysm embolization using Guglielmi detachable coils(GDC) is gaining acceptance as a viable alternative to surgery in the treatment of cerebral aneurysms. During GDC treatment of cerebral aneurysms, thromboembolic events are the most frequent complications. As risk factors of thromboembolic events, large aneurysms, wide-necked aneurysms, use of the balloon-assisted technique and protruding coils into the parent arteries are previously reported. From March, 1997 till August, 2004, 270 consecutive patients were treated with GDC embolization at our institute. Fourteen (5.2%) patients with 14 aneurysms of these 270 patients presented with protruding coils into the parent vessels. Twelve aneurysms of these 14 aneurysms were small (diameter < 10 mm), and two were large (diameter 15 mm). Nine aneurysms had small necks (neck diameter < 4 mm), and five had wide necks(neck diameter > 4 mm). The fundus-toneck ratio ranged from 1.04 to 2.78, with an average of 1.53. In this series, ten patients (71%) were treated with balloon-remodelling technique because every patient had either a wide-necked aneurysm or complicated morphologic factors. These 14 aneurysms were divided into two groups according to the mode of coil protrusion, loop type and tail type protrusion. The first coil was protruded in five (36%) cases of 14 patients, four of these five cases presented with the loop type protrusion. The last coil was protruded in seven cases (50%), Five of these seven cases presented with the tail type protrusion. Diffusion-weighted imaging abnormalities were found for seven (50%) of 14 patients within 24 hours of the coiling procedures. Three (21%) of 14 patients showed small lesions (< 5 mm) in the subcortical white matter at the border zone or perforating regions. In four (29%) patients, large territorial infarctions (> 5 mm) were detected. Symptomatic complications occurred in four (29%) patients, and all of these four patients presented the loop type protrusion. One patient who had small infarctions experienced minimal deficits (slight motor weakness, quadrantic hemianopsia) after six days postprocedure and fully recovered by discharge after stronger systemic heparinization (24000U, for three days), aspirin (100 mg/day) and Ticlopidine (100 mg/day). Three patients who had large territorial infarctions experienced moderate deficits. Two patients were treated with stronger systemic heparinization and one with Argatroban (60 mg/day, for two days), and following aspirin (100 mg/day) and Ticlopidine (100 mg/day). Finally, two patiens were discharged with permanent minimal deficits (hypoesthesia only) and one with moderate hemiparesis. The infarctions related to the GDC procedures were more common sequelae in wide-necked aneurysms and coil protrusions, especially loop type protrusion. Although permanent neurological deficits were rare, the high rate of thromboembolic events associated with coil protrusion suggest that more aggressive medical treatment should be considered.

Expression of peroxisome proliferator-activated receptor-gamma in renal ischemia-reperfusion injury.

The pathogenesis of ischemia-reperfusion injury is known to involve cytokines and particularly surface adhesion molecules, the expression of which initiates the attachment of inflammatory cells. Peroxisome proliferator-activated receptor (PPAR)-gamma is considered an important immunomodulatory factor as well as a fatty acid regulator. In this study, we researched the expression of PPAR-gamma in renal ischemia-reperfusion injury of the rat. The right kidney was harvested and left renal artery and vein were clamped under laparotomy. The kidney was reperfused after 90 minutes of ischemia, and rats were sacrificed at 0, 1.5, 3, 5, 12, and 24 hours after reperfusion. PPAR-gamma expression was analyzed by immunohistochemical staining using monoclonal antibody. In normal kidney, PPAR-gamma staining was weak on endothelial cells, including mesangial cells. On the other hand, PPAR-gamma staining was weak on interstitial cells and strong on collecting ducts of medulla. From 1.5 to 5 hours after reperfusion, PPAR-gamma staining was strong on endothelial cells, moderate on interstitial cells, and strong on collecting ducts. Twelve hours after reperfusion, PPAR-gamma staining was weak on endothelial cells, moderate on interstitial cells, and strong on collecting ducts. PPAR-gamma is induced on collecting ducts, interstitial cells, and endothelial cells in a rat model having renal ischemia-reperfusion injury.

Synergistic activity of activin A and basic fibroblast growth factor on tyrosine hydroxylase expression through Smad3 and ERK1/ERK2 MAPK signaling pathways.

Activin has previously been shown to act as a nerve cell survival factor and to have neurotrophic effects on neurons. However, the role of activin in regulating neurotransmitter expression in the central nervous system and the exact mechanisms involved in this process are poorly understood. In the present study, we report that activin A and basic fibroblast growth factor (bFGF) synergistically increased the protein level of tyrosine hydroxylase (TH), and also greatly increased the TH mRNA level, in both mouse E14 striatal primary cell cultures and the hippocampal neuronal cell line HT22. Activin A and bFGF cooperatively stimulated nuclear translocation of Smad3 and specifically activated ERK1/2, but not p38 or JNK. Interestingly, a specific inhibitor for MEK, U0126, efficiently blocked the induction of TH promoter activity by activin A and bFGF, indicating that activin A collaborated with bFGF signaling to induce the TH gene through selective activation of ERK-type MAP kinase in mouse striatal and HT22 cells. These data suggest that activin A may act in concert with bFGF for the development of TH-positive neurons.

Study of peroxisome proliferator-activated receptor (PPAR)-gamma in renal ischemia-reperfusion injury.

Recent studies of ischemia-reperfusion (I/R) injury have focused on the function of neutrophils, the action mechanism of inflammatory cytokines. However, few reports have addressed peroxisome proliferator-activated receptor (PPAR)-gamma. PPAR-gamma is a ligand-activated transcriptional factor belonging to the steroid receptor superfamily. It plays a role in both adipocyte differentiation and tumorigenesis. We researched the expression of PPAR-gamma in renal I/R injury of the rat. Male Lewis rats were used. The right kidney was harvested and the left renal artery and vein were clamped at 90 minutes of ischemic time. Rats were killed at 0, 1.5, 3, 5, and 12 hours after reperfusion. PPAR-gamma expression was studied by immunohistostaining. PPAR-gamma expression was observed only on mesangial and endothelial cells of normal kidney. From 1.5 to 3 hours after reperfusion, PPAR-gamma expression gradually became stronger on mesangial and endothelial cells. PPAR-gamma expression was most intense on mesangial cells and endothelial cells at 3 hours after reperfusion. Twelve hours after reperfusion, necrosis extended throughout the ischemic kidney and nearly all the tubular epithelial cells were destroyed, but 12 hours after reperfusion PPAR-gamma expression gradually became weaker on mesangial and endothelial cells. PPAR-gamma was expressed in the rat model having renal I/R injury. Several hours after maximal of PPAR-gamma expression, maximal renal I/R injury was observed. These results may indicate a relationship between PPAR-gamma expression and renal I/R injury.

Queen and worker policing in monogynous and monandrous colonies of a primitively eusocial wasp.

Kin-selection theory predicts that a worker prefers to produce her own sons in a colony with monandry and monogyny because relatedness to her sons (0.5) and nephews (0.375) exceeds that to brothers (0.25). In spite of this prediction, recent studies reveal that workers police each other (mutual-worker egg removal) even in monandrous and monogynous colonies. We conducted field and laboratory studies to evaluate queen and worker policing in queen-right colonies of the primitively eusocial wasp Polistes chinensis antennalis. Genetic studies using microsatellite markers, as well as extensive observations of natural colonies, revealed that both queen and workers removed both queen- and worker-laid eggs in monogynous and monandrous colonies. The queen's eggs survived to hatching more successfully than those of the workers (88.5% versus 1.4%). We discuss the likely factors to explain these worker-policing behaviours.