Heparin inhibits endothelin-1 production in cultured rat mesangial cells

Heparin inhibits endothelin-1 production in cultured rat mesangial cells. The present study was designed to examine whether heparin inhibits basal or stimulated endothelin-1 production by arginine vasopressin (AVP) and platelet-derived growth factor (PDGF) in cultured rat mesangial cells. In addition, the reversibility of the heparin effect on mesangial cell endothelin-1 production was examined. AVP and PDGF stimulated endothelin-1 secretion in a concentration-dependent manner in these cells. Heparin (10 to 100 U/ml) exhibited concentration-related inhibition of AVP- and PDGF-stimulated endothelin-1 secretion. Heparin also had weak but significant inhibitory effects on basal endothelin-1 secretion in these cells. The protein kinase (PKC)-activating phorbor ester, phorbor myristate acetate (PMA), stimulated endothelin-1 secretion and heparin inhibited PMA-stimulated endothelin-1 secretion. In addition, the inhibitory effect of heparin was completely abolished in PKC-depleted mesangial cells. Mesangial cells which were exposed to a high concentration (100 U/ml) of heparin for 24 hours were capable of producing endothelin-1 after a short lag period of removal of heparin from the culture medium. These mesangial cells also showed recovery of responses to AVP and PDGF by secreting a significantly greater amount of endothelin-1 than the non-stimulated level. These results indicate that heparin potently inhibits mesangial cell endothelin-1 production, especially when stimulated by AVP or PDGF. This inhibitory effect of heparin is probably PKC dependent, and reversible

Direct Observation of ATP-Induced Conformational Changes in Single P2X4 Receptors

The ATP-gated P2X4 receptor is a cation channel, which is important in various pathophysiological events. The architecture of the P2X4 receptor in the activated state and how to change its structure in response to ATP binding are not fully understood. Here, we analyze the architecture and ATP-induced structural changes in P2X4 receptors using fast-scanning atomic force microscopy (AFM). AFM images of the membrane-dissociated and membrane-inserted forms of P2X4 receptors and a functional analysis revealed that P2X4 receptors have an upward orientation on mica but lean to one side. Time-lapse imaging of the ATP-induced structural changes in P2X4 receptors revealed two different forms of activated structures under 0 Ca2+ conditions, namely a trimer structure and a pore dilation-like tripartite structure. A dye uptake measurement demonstrated that ATP-activated P2X4 receptors display pore dilation in the absence of Ca2+. With Ca2+, the P2X4 receptors exhibited only a disengaged trimer and no dye uptake was observed. Thus our data provide a new insight into ATP-induced structural changes in P2X4 receptors that correlate with pore dynamics

Population‑based prostate‑specific antigen screening for prostate cancer may have an indirect effect on early detection through opportunistic testing in Kusatsu City, Shiga, Japan

Prostate cancer is the most common genitourinary cancer in men. Population-based serum prostate-specific antigen (PSA) testing is used to screen men for the early detection of asymptomatic prostate cancer. The present study compared the features of patients with prostate cancer in Kusatsu City, the only municipality in Shiga Prefecture of Japan to implement organized PSA screening, with those in other municipalities. The target population for organized PSA screening by mail invitation was men ≥50 years. Patients were pathologically diagnosed via prostate biopsy because of elevated serum PSA. This multicenter observational study was subsequently conducted in 14 hospitals. The following information was extracted from patient records: age, reason for PSA testing, initial PSA level, Gleason score, clinical stage, and place of residence. Risk classification was defined as low, intermediate, high, and advanced. Each patient was stratified according to their city/town. A total of 984 patients diagnosed with prostate cancer in Shiga in 2012 and 2017 were analyzed, of which 955 (97%) were opportunistically tested, with the remaining 29 (3%) assessed by organized screening. In Kusatsu, 93 patients were diagnosed, of whom 26 (28%) were detected by organized screening. By contrast, only three of 891 patients (0.3%) were detected by organized screening in other municipalities. Of patients in Kusatsu, cases identified by opportunistic testing had a higher initial PSA value (P=0.010) than those identified by organized screening. However, patients detected through opportunistic testing in Kusatsu City were younger (P=0.034), had a lower PSA value (P=0.001), and improved risk classification (P<0.001) than those in other municipalities. It was concluded that more patients were diagnosed with early-stage cancer by organized PSA screening. Furthermore, population-based PSA screening in Kusatsu City may have indirectly affected early detection, even by opportunistic testing

Altered expression of synaptic proteins and adhesion molecules in the hippocampus and cortex following the onset of diabetes in nonobese diabetic mice

Abstract Mounting evidence links Type 1 diabetes (T1D) with cognitive dysfunction, psychiatric disorders, and synaptic alterations; however, the underlying mechanism remains unclear. Numerous synaptic proteins and synaptic adhesion molecules (SAMs) that orchestrate synaptic formation, restructuring, and elimination are essential for proper brain function. Currently, it is unclear whether the pathogenesis of T1D is related to the expression of synaptic proteins and SAMs. Here, we investigated whether T1D mice exhibited altered synaptic protein and SAM expression in the hippocampus and cortex. We discovered that T1D mice exhibited partially decreased levels of excitatory and inhibitory synapse proteins and SAMs, such as neurexins, neuroligins, and synaptic cell adhesion molecules. We also found that compared to control mice, T1D mice showed a marginal decrease in body weight and a significant increase in plasma glycoalbumin levels (a hyperglycemia marker). These results provide novel molecular‐level insights into synaptic dysfunction in mice with T1D

Acute bout of exercise induced prolonged muscle glucose transporter-4 translocation and delayed counter-regulatory hormone response in type 1 diabetes - Fig 6

<p><b>The effect of a single bout of exercise on level of GLUT-4 translocation (A) and glucose-6-phosphate level (B).</b> White bar, CON+EX; Black bar, STZ+EX; Gray bar, STZ. * P < 0.05 vs. 0 h, † P < 0.05 vs. STZ. Values are represented as mean ± SE. The gels were electrophoresed under the same experimental conditions.</p

Acute resistance exercise-induced IGF1 expression and subsequent GLUT4 translocation

Acute aerobic exercise (AE) is a major physiological stimulus for skeletal muscle glucose uptake through activation of 5 AMP-activated protein kinase (AMPK). However, the regulation of glucose uptake by acute resistance exercise (RE) remains unclear. To investigate the intracellular regulation of glucose uptake after acute RE versus acute AE, male Sprague-Dawley rats were divided into three groups: RE, AE, or nonexercise control. After fasting for 12h overnight, the right gastrocnemius muscle in the RE group was exercised at maximum isometric contraction via percutaneous electrical stimulation (3x10sec, 5 sets). The AE group ran on a treadmill (25m/min, 60min). Muscle samples were taken 0, 1, and 3h after completion of the exercises. AMPK, Ca2+/calmodulin-dependent protein kinase II, and TBC1D1 phosphorylation were increased immediately after both forms of exercise and returned to baseline levels by 3h. Muscle IGF1 expression was increased by RE but not AE, and maintained until 3h after RE. Additionally, Akt and AS160 phosphorylation were sustained for 3h after RE, whereas they returned to baseline levels by 3h after AE. Similarly, GLUT4 translocation remained elevated 3h after RE, although it returned to the baseline level by 3h after AE. Overall, this study showed that AMPK/TBC1D1 and IGF1/Akt/AS160 signaling were enhanced by acute RE, and that GLUT4 translocation after acute RE was more prolonged than after acute AE. These results suggest that acute RE-induced increases in intramuscular IGF1 expression might be a distinct regulator of GLUT4 translocation