Publications

Soshiho-tang (Xiao-chai-hu-tang in Chinese and Sho-saiko-to in Japanese) has been widely used for its various pharmacological effects, which include anti-inflammatory, antioxidant, antihepatic fibrosis, and antitumor properties. To evaluate the safety of Soshiho-tang water extract (SST), we tested its subchronic toxicity in male and female Crl:CD (SD) rats. Rats were orally treated with four different doses (0, 500, 1000, and 2000 mg/kg/day) of SST administered for 13 weeks. Mortality, clinical signs, body weight changes, food and water consumption changes, ophthalmology, urinalysis, hematological and biochemical parameters, gross findings, organ weights, and histological markers were monitored during the study. The SST treatment did not result in any toxicologically significant changes in mortality, clinical signs, body weights, food and water consumption, ophthalmoscopy, urinalysis, hematological and serum biochemical parameters, gross findings, organ weights, or histopathology. Histological analysis did not show any liver or kidney alteration. We concluded that the 13-week repeated oral administration of SST did not cause any adverse effects in rats at dosage levels of ≤2000 mg/kg/day. Under these experimental conditions, the no-observed-adverse-effect level was concluded to be 2000 mg/kg/day for both sexes.

Hypothalamic feeding circuits are essential for the maintenance of energy balance. There have been intensive efforts to discover new biological molecules involved in these pathways. Here we report that central administration of clusterin, also called apolipoprotein J, causes anorexia, weight loss and activation of hypothalamic signal transduction-activated transcript-3 in mice. In contrast, inhibition of hypothalamic clusterin action results in increased food intake and body weight, leading to adiposity. These effects are likely mediated through the mutual actions of the low-density lipoprotein receptor-related protein-2, a potential receptor for clusterin, and the long-form leptin receptor. In response to clusterin, the low-density lipoprotein receptor-related protein-2 binding to long-form leptin receptor is greatly enhanced in cultured neuronal cells. Furthermore, long-form leptin receptor deficiency or hypothalamic low-density lipoprotein receptor-related protein-2 suppression in mice leads to impaired hypothalamic clusterin signalling and actions. Our study identifies the hypothalamic clusterin-low-density lipoprotein receptor-related protein-2 axis as a novel anorexigenic signalling pathway that is tightly coupled with long-form leptin receptor-mediated signalling.

Normal leptin signaling is essential for the maintenance of body weight homeostasis. Proopiomelanocortin- and agouti-related peptide (AgRP)-producing neurons play critical roles in regulating energy metabolism. Our recent work demonstrates that deletion of Rho-kinase 1 (ROCK1) in the AgRP neurons of mice increased body weight and adiposity. Here, we report that selective loss of ROCK1 in AgRP neurons caused a significant decrease in energy expenditure and locomotor activity of mice. These effects were independent of any change in food intake. Furthermore, AgRP neuron-specific ROCK1-deficient mice displayed central leptin resistance, as evidenced by impaired Signal Transducer and Activator of Transcription 3 activation in response to leptin administration. Leptin's ability to hyperpolarize and decrease firing rate of AgRP neurons was also abolished in the absence of ROCK1. Moreover, diet-induced and genetic forms of obesity resulted in reduced ROCK1 activity in murine arcuate nucleus. Of note, high-fat diet also impaired leptin-stimulated ROCK1 activity in arcuate nucleus, suggesting that a defect in hypothalamic ROCK1 activity may contribute to the pathogenesis of central leptin resistance in obesity. Together, these data demonstrate that ROCK1 activation in hypothalamic AgRP neurons is required for the homeostatic regulation of energy expenditure and adiposity. These results further support previous work identifying ROCK1 as a key regulator of energy balance and suggest that targeting ROCK1 in the hypothalamus may lead to development of antiobesity therapeutics.

The Ser/Thr Rho kinase 1 (ROCK1) is known to have major roles in a wide range of cellular activities, including those involved in tumour metastasis and apoptosis. Here we identify an indispensable function of ROCK1 in metabolic stress-induced autophagy. Applying a proteomics approach, we characterize Beclin1, a proximal component of the phosphoinositide 3-kinase class III lipid-kinase complex that induces autophagy, as an interacting partner of ROCK1. Upon nutrient deprivation, activated ROCK1 promotes autophagy by binding and phosphorylating Beclin1 at Thr119. This results in the specific dissociation of the Beclin1-Bcl-2 complex without affecting the Beclin1-UVRAG interaction. Conversely, inhibition of ROCK1 activity increases Beclin1-Bcl-2 association, thus reducing nutritional stress-mediated autophagy. Genetic knockout of ROCK1 function in mice also leads to impaired autophagy as evidenced by reduced autophagosome formation. These results show that ROCK1 acts as a prominent upstream regulator of Beclin1-mediated autophagy and maintains a homeostatic balance between apoptosis and autophagy.

Obesity has increased at an alarming rate in recent years and is now a worldwide public health problem. Elucidating the mechanisms behind the metabolic dysfunctions associated with obesity is of high priority. The metabolic function of Rho-kinase (Rho-associated coiled-coil-containing kinase; ROCK) has been the subject of a great deal of investigation in metabolic-related diseases. It appears that inhibition of ROCK activity is beneficial for the treatment of a wide range of cardiovascular-related diseases. However, recent studies with genetic models of ROCK demonstrate that ROCK plays a positive role in insulin and leptin signaling. Here we discuss the newly identified functions of ROCK in regulating glucose and energy metabolism, with particular emphasis on metabolic actions of insulin and leptin.

BACKGROUND: Recently, it has been suggested that enhancement of incretin effect improves cardiac function. We investigated the effect of a DPP-IV inhibitor, des-fluoro-sitagliptin, in reducing occurrence of restenosis in carotid artery in response to balloon injury and the related mechanisms.

METHODS AND FINDINGS: Otsuka Long-Evans Tokushima Fatty rats were grouped into four: control (normal saline) and sitagliptin 100, 250 and 500 mg/kg per day (n = 10 per group). Sitagliptin or normal saline were given orally from 1 week before to 2 weeks after carotid injury. After 3 weeks of treatment, sitagliptin treatment caused a significant and dose-dependent reduction in intima-media ratio (IMR) in obese diabetic rats. This effect was accompanied by improved glucose homeostasis, decreased circulating levels of high-sensitivity C-reactive protein (hsCRP) and increased adiponectin level. Moreover, decreased IMR was correlated significantly with reduced hsCRP, tumor necrosis factor-α and monocyte chemoattractant protein-1 levels and plasminogen activator inhibitor-1 activity. In vitro evidence with vascular smooth muscle cells (VSMCs) demonstrated that proliferation and migration were decreased significantly after sitagliptin treatment. In addition, sitagliptin increased caspase-3 activity and decreased monocyte adhesion and NFκB activation in VSMCs.

CONCLUSIONS: Sitagliptin has protective properties against restenosis after carotid injury and therapeutic implications for treating macrovascular complications of diabetes.

BACKGROUND: The role of pentraxin-3 (PTX3) in the development of insulin resistance is still not clear. We aimed to test 1) whether circulating PTX3 levels are associated with insulin resistance and 2) whether changes in PTX3 levels after the physical activity are associated with changes in insulin resistance.

METHODS: Fifty-seven overweight or obese children (39 boys, 18 girls; age: 12.04±0.82y, BMI: 26.5±1.2 kg/m²) participated in the study. All participants were housed together and their amount of physical activity (1823.5±1.34 kcal/day) and food intake (1882±68.8 kcal/day) were tightly controlled.

RESULTS: Circulating PTX3 levels at baseline were negatively associated with fasting insulin (r=-.336, p=0.012) and homeostasis model assessment of insulin resistance (HOMA-IR) (r=-.334, p=0.014) even after adjustment for BMI and Tanner stage. The degree of change in PTX3 levels notably associated with changes in fasting insulin (r=-.280, p=0.035) and HOMA-IR (r=-.281, p=.034) in response to the physical activity intervention. Subgroup analysis further indicates that HOMA-IR was improved more in subjects whose PTX3 levels were increased compared with subjects who PTX3 levels were decreased (HOMA-IR delta: -2.33±1.3 vs -1.46±0.70, p=0.004).

CONCLUSION: PTX3 is negatively associated with insulin resistance and associated with changes in insulin resistance induced by physical activity in overweight and obese children.

Leptin regulates energy balance. However, knowledge of the critical intracellular transducers of leptin signaling remains incomplete. We found that Rho-kinase 1 (ROCK1) regulates leptin action on body weight homeostasis by activating JAK2, an initial trigger of leptin receptor signaling. Leptin promoted the physical interaction of JAK2 and ROCK1, thereby increasing phosphorylation of JAK2 and downstream activation of Stat3 and FOXO1. Mice lacking ROCK1 in either pro-opiomelanocortin (POMC) or agouti-related protein neurons, mediators of leptin action, displayed obesity and impaired leptin sensitivity. In addition, deletion of ROCK1 in the arcuate nucleus markedly enhanced food intake, resulting in severe obesity. Notably, ROCK1 was a specific mediator of leptin, but not insulin, regulation of POMC neuronal activity. Our data identify ROCK1 as a key regulator of leptin action on energy homeostasis.

OBJECTIVE: The aims of this study were to investigate the long-term effect of complex decongestive therapy (CDT) on lymphedema volume reduction, especially considering the proximal and distal parts of the leg, and to evaluate the utility of pre-therapy lymphoscintigraphy in predicting the response to CDT in patients with lower-limb lymphedema after surgery for gynecologic cancer.

METHODS: Medical records of 158 patients with secondary lymphedema of unilateral leg after surgery for gynecological cancer were reviewed retrospectively. They were treated with two weeks of CDT along with self-administered home therapy and were followed up for 24 months. Whole, proximal and distal leg volume was serially measured by using an optoelectric volumeter prior to and immediately after therapy, and follow-up visits at months 3, 6, 12 and 24. Lymphoscintigraphy was performed prior to therapy.

RESULTS: The percent volume reduction was 22.1% in the whole leg, 30.9% in the distal leg and 18.4% in the proximal leg immediately after CDT. The volume reduction was maintained for 24 months, but the distal leg was significantly well maintained better than the proximal leg. Extremity radioisotope uptake ratio (EUR) among lymphoscintigraphic findings could predict the improvement of lymphedema volume in the distal, proximal and whole leg.

CONCLUSIONS: This study suggests that the long-term edema reducing effects of CDT are better maintained in the distal leg than in the proximal part, and initial lymphoscintigraphic quantitative finding may usefully predict the short and long-term response to CDT.