Androgen action via testicular arteriole smooth muscle cells is important for leydig cell function, vasomotion and testicular fluid dynamics

Regulation of blood flow through the testicular microvasculature by vasomotion is thought to be important for normal testis function as it regulates interstitial fluid (IF) dynamics which is an important intra-testicular transport medium. Androgens control vasomotion, but how they exert these effects remains unclear. One possibility is by signalling via androgen receptors (AR) expressed in testicular arteriole smooth muscle cells. To investigate this and determine the overall importance of this mechanism in testis function, we generated a blood vessel smooth muscle cell-specific AR knockout mouse (SMARKO). Gross reproductive development was normal in SMARKO mice but testis weight was reduced in adulthood compared to control littermates; this reduction was not due to any changes in germ cell volume or to deficits in testosterone, LH or FSH concentrations and did not cause infertility. However, seminiferous tubule lumen volume was reduced in adult SMARKO males while interstitial volume was increased, perhaps indicating altered fluid dynamics; this was associated with compensated Leydig cell failure. Vasomotion was impaired in adult SMARKO males, though overall testis blood flow was normal and there was an increase in the overall blood vessel volume per testis in adult SMARKOs. In conclusion, these results indicate that ablating arteriole smooth muscle AR does not grossly alter spermatogenesis or affect male fertility but does subtly impair Leydig cell function and testicular fluid exchange, possibly by locally regulating microvascular blood flow within the testis

PPAR-γ Ligands Repress TGFβ-Induced Myofibroblast Differentiation by Targeting the PI3K/Akt Pathway: Implications for Therapy of Fibrosis

Transforming growth factor beta (TGFβ) induced differentiation of human lung fibroblasts to myofibroblasts is a key event in the pathogenesis of pulmonary fibrosis. Although the typical TGFβ signaling pathway involves the Smad family of transcription factors, we have previously reported that peroxisome proliferator-activated receptor-γ (PPAR-γ) ligands inhibit TGFβ-mediated differentiation of human lung fibroblasts to myofibroblasts via a Smad-independent pathway. TGFβ also activates the phosphatidylinositol 3 kinase/protein kinase B (PI3K/Akt) pathway leading to phosphorylation of AktS473. Here, we report that PPAR-γ ligands, 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid (CDDO) and 15-deoxy-(12,14)-15d-prostaglandin J2 (15d-PGJ2), inhibit human myofibroblast differentiation of normal and idiopathic pulmonary fibrotic (IPF) fibroblasts, by blocking Akt phosphorylation at Ser473 by a PPAR-γ-independent mechanism. The PI3K inhibitor LY294002 and a dominant-negative inactive kinase-domain mutant of Akt both inhibited TGFβ-stimulated myofibroblast differentiation, as determined by Western blotting for α-smooth muscle actin and calponin. Prostaglandin A1 (PGA1), a structural analogue of 15d-PGJ2 with an electrophilic center, also reduced TGFβ-driven phosphorylation of Akt, while CAY10410, another analogue that lacks an electrophilic center, did not; implying that the activity of 15d-PGJ2 and CDDO is dependent on their electrophilic properties. PPAR-γ ligands inhibited TGFβ-induced Akt phosphorylation via both post-translational and post-transcriptional mechanisms. This inhibition is independent of MAPK-p38 and PTEN but is dependent on TGFβ-induced phosphorylation of FAK, a kinase that acts upstream of Akt. Thus, PPAR-γ ligands inhibit TGFβ signaling by affecting two pro-survival pathways that culminate in myofibroblast differentiation. Further studies of PPAR-γ ligands and small electrophilic molecules may lead to a new generation of anti-fibrotic therapeutics

Online Detection of Out-of-Step Condition Using PMU-Determined System Impedances

This paper presents a robust and adaptive out-of-step (OOS) protection algorithm, using wide-area information, that can be applied on tie-lines in observable power systems. The developed algorithm is based upon real-time computation of the system impedance and makes use of the well-known power-angle characteristic. In this way, a setting-less OOS concept in real-time environment is developed, which is applicable for tie-lines in an arbitrary power system. Furthermore, the developed protection algorithm is installed on hardware and is verified by numerous tests. The performance of the new hardware implementation is compared to the traditional impedance-based OOS protection methods. The results confirm that the proposed algorithm detects OOS conditions faster and more reliably than the traditional impedance-based solutions.Intelligent Electrical Power Grid

Out-of-Step Protection Based on Discrete Angle Derivatives

This paper presents an out-of-step protection algorithm based on angle derivatives, which makes use of wide-area measurements and can be applied on arbitrary tie-lines in electrical power systems. The developed algorithm uses PMU measurements that are taken at both ends of a transmission line. Based on the changes of the electrical quantities in the power system, the algorithm detects unstable system conditions. Thus, the developed solution is settingless and can be easily applied where an out-of-step condition is expected. The concept is deployed by using an industrial controller and tested by conducting numerous hardware-in-the-loop simulations. Additionally, recorded data from actual out-of-step events in the Icelandic power system are used to validate the developed algorithm. The performance of the implemented method is compared against the traditional impedance-based out-of-step protection methods. The results confirm that the proposed algorithm detects out-of-step conditions more reliably and faster than the traditional impedance-based solutions.Intelligent Electrical Power Grid

Histological comparison of adult SMARKO and control testes.

<p><b>A.</b> Most seminiferous tubules in SMARKO testes looked comparable to control testes at d100, however, a small proportion (10%) were abnormal with disturbed spermatogenesis (*). Lumens appeared smaller in many seminiferous tubules in SMARKO testes at d100, compared to controls. <b>B.</b> There was no significant change in the total germ cell volume in SMARKO testes at d100, compared to controls. <b>C.</b> There was no significant change in seminiferous tubule diameter in SMARKO testes at d100, compared to controls. The percentage (<b>D</b>) <b>and volume</b> (<b>E</b>) of seminiferous tubule lumen was significantly reduced at d100 in SMARKO testes compared to controls. Scale bars  = 50 µm. Values are means ± S.E.M. (n = 4–6 mice), * p<0.05, ** p<0.01 compared to controls littermates.</p

Taqman primer details.

<p>Taqman primer details.</p

Hormone concentrations in SMARKO and control adult males.

<p><b>A.</b> Serum follicle stimulating hormone (FSH) concentrations were not significantly different in SMARKO males, compared to controls, at d50 or d100. <b>B.</b> Serum luteinising hormone (LH) concentrations were significantly increased in SMARKO males at d100, but not at d50 compared to controls. <b>C.</b> Serum testosterone concentrations were not significantly different in SMARKO males, compared to controls at d50 or d100. <b>D.</b> Intra-testicular testosterone concentrations were not significantly altered in SMARKO males at d100. Values are mean ± SEM (n = 8–27 mice), ** p<0.01, compared to control littermates.</p

Evaluation of Leydig cell (LC) function in SMARKO testes.

<p><b>A.</b> There was a significant increase in interstitial volume in SMARKO adult testes. <b>B.</b> Immunostaining for 3βHSD (red) and AR (green) demonstrating that LCs (arrow) and SCs (arrowhead) express AR in both SMARKO and control testes. <b>C.</b> Quantification of LC size and number highlighting no significant change in either in SMARKO testes, compared to controls. <b>D.</b> Relative expression of steroidogenesis enzymes (StAR, cyp11a, 3βHSD, Cyp17 and 17βHSD) and Inls3 in d100 control and SMARKO testes. Values are mean ± SEM (n = 4–6 mice), ** p<0.01, compared to controls littermates. Scale bars  = 50 µm.</p