Macrophage-Specific Toll Like Receptor 9 (TLR9) Causes Corpus Cavernosum Dysfunction in Mice Fed a High Fat Diet

Author(s):  
Fernanda Priviero ◽  
Fabiano Calmasini ◽  
Vanessa Dela Justina ◽  
Camilla F. Wenceslau ◽  
Cameron G. McCarthy ◽  
...  
2018 ◽  
Vol 32 (S1) ◽  
Author(s):  
Fernanda Priviero ◽  
Fabiano Beraldi Calmasini ◽  
Cameron McCarthy ◽  
Camilla Ferreira Wenceslau ◽  
Edson Antunes ◽  
...  

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Ellen Jackson ◽  
Elizabeth Rendina-Ruedy ◽  
Matt Priest ◽  
Brenda Smith ◽  
Veronique Lacombe

Diabetes mellitus is an epidemic disease characterized by alterations in glucose transport, which is tightly regulated by a family of specialized proteins called the glucose transporters (GLUTs). Although diabetic cardiomyopathy is a common complication in diabetic patients, its pathogenesis is still not well understood. Toll-like receptor (TLR) 4, which plays a central role in pathogen recognition by the innate immune system, may also play a critical role in linking inflammation and metabolic disease. We hypothesized that TLR4 activation triggers cardiac insulin resistance. We used mice with a loss-of function mutation in TLR4 (C3H/HeJ) and age-matched wild-type (WT, C57BL/6N) mice (n=8/group) to investigate how feeding a high-fat diet (HFD, 60% kcal from fat) for 16 weeks affected whole-body and cardiac glucose metabolism. After 16 weeks, WT mice fed a HFD were obese and developed hyperglycemia and insulin resistance compared to WT mice on a control diet (10% kcal from fat). The C3H/HeJ mice were partially protected against HFD-induced obesity and insulin resistance. In the heart, WT mice fed a HFD had a 30% decrease (P<0.05) in GLUT4 protein content as measured by Western Blot of cardiac crude membrane protein extracts. In contrast, the loss-of-function point mutation in TLR4 partially rescued cardiac GLUT4 content in the face of a HFD. Interestingly, there was a 40% increase (P<0.05) in the novel GLUT isoform, GLUT8, in the heart when mice of either genotype were fed a HFD. Additionally, GLUT4 protein content was negatively (P<0.05) correlated with GLUT8 content in the myocardium, suggesting that GLUT8 may act as a compensatory mechanism in the face of HFD-induced GLUT4 downregulation. Phosphorylated Akt, a key protein of the insulin signaling pathway, was positively (P<0.05) correlated with GLUT4 content, while the basal/inactive form was negatively correlated. In conclusion, these data suggest that activation of TLR4 activation during diabetes and obesity alters glucose transport by an Akt mechanism, and as such is a pathogenic factor during peripheral and cardiac insulin resistance. Overall, TLR4 appears to be a key modulator in the cross-talk between inflammatory and metabolic pathways, as well as a potential therapeutic target for diabetes.


2015 ◽  
Vol 12 (2) ◽  
pp. 2589-2597 ◽  
Author(s):  
QIUFANG OUYANG ◽  
ZIYANG HUANG ◽  
HUILI LIN ◽  
JINGQIN NI ◽  
HUIXIA LU ◽  
...  

2019 ◽  
Vol 16 (4) ◽  
pp. S41-S42
Author(s):  
F. Priviero ◽  
F. Calmasini ◽  
C.G. McCarthy ◽  
C. Wenceslau ◽  
E. Antunes ◽  
...  

2015 ◽  
Vol 309 (3) ◽  
pp. R304-R313 ◽  
Author(s):  
Ryan P. McMillan ◽  
Yaru Wu ◽  
Kevin Voelker ◽  
Gabrielle Fundaro ◽  
John Kavanaugh ◽  
...  

Toll-like receptor-4 (TLR-4) is elevated in skeletal muscle of obese humans, and data from our laboratory have shown that activation of TLR-4 in skeletal muscle via LPS results in decreased fatty acid oxidation (FAO). The purpose of this study was to determine whether overexpression of TLR-4 in skeletal muscle alters mitochondrial function and whole body metabolism in the context of a chow and high-fat diet. C57BL/6J mice (males, 6–8 mo of age) with skeletal muscle-specific overexpression of the TLR-4 (mTLR-4) gene were created and used for this study. Isolated mitochondria and whole muscle homogenates from rodent skeletal muscle (gastrocnemius and quadriceps) were investigated. TLR-4 overexpression resulted in a significant reduction in FAO in muscle homogenates; however, mitochondrial respiration and reactive oxygen species (ROS) production did not appear to be affected on a standard chow diet. To determine the role of TLR-4 overexpression in skeletal muscle in response to high-fat feeding, mTLR-4 mice and WT control mice were fed low- and high-fat diets for 16 wk. The high-fat diet significantly decreased FAO in mTLR-4 mice, which was observed in concert with elevated body weight and fat, greater glucose intolerance, and increase in production of ROS and cellular oxidative damage compared with WT littermates. These findings suggest that TLR-4 plays an important role in the metabolic response in skeletal muscle to high-fat feeding.


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