Role of adiponectin and inflammation in insulin resistance of Mc3r and Mc4r knockout mice

Objective: To investigate the involvement of hypoadiponectinemia and inflammation in coupling obesity to insulin resistance in melanocortin-3 receptor and melanocortin-4 receptor knockout (KO) mice (Mc3/4rKO). Research Methods and Procedures: Sera and tissue were collected from 6-month-old Mc3rKO, Mc4rKO, and wild-type C57BL6J litter mates maintained on low-fat diet or exposed to high-fat diet (HFD) for 1 or 3 months. Inflammation was assessed by both real-time polymerase chain reaction analysis of macrophage-specific gene expression and immunohistochemistry. Results: Mc4rKO exhibited hypoadiponectinemia, exacerbated by HFD and obesity, previously reported in murine models of obesity. Mc4r deficiency was also associated with high levels of macrophage infiltration of adipose tissue, again exacerbated by HFD. In contrast, Mc3rKO exhibited normal serum adiponectin levels, irrespective of diet or obesity, and a delayed inflammatory response to HFD relative to Mc4rKO. Discussion: Our findings suggest that severe insulin resistance of Mc4rKO fed a HFD, as reported in other models of obesity such as leptin-deficient (Lep ob/Lepob) and KK-Ay mice, is linked to reduced serum adiponectin and high levels of inflammation in adipose tissue. Conversely, maintenance of normal serum adiponectin may be a factor in the relatively mild insulin-resistant phenotype of severely obese Mc3rKO. Mc3rKO are, thus, a unique mouse model where obesity is not associated with reduced serum adiponectin levels. A delay in macrophage infiltration of adipose tissue of Mc3rKO during exposure to HFD may also be a factor contributing to the mild insulin resistance in this model. Copyright © 2007 NAASO

Slope Map of the Moon’s South Pole (85°S to Pole)

This map is based on data collected by the Lunar Orbiter Laser Altimeter (LOLA) onboard the Lunar Reconnaissance Orbiter (LRO). The map shows slopes derived from the LOLA 10-m elevation product (NASA Goddard Space Flight Center; Smith et al., 2010; Smith et al., 2017). The slope is represented with four traditional colors 0° to 5° (bright green), 5° to 10° (dark green), 10° to 15° (yellow), and >15° (red). A second version of the map, with colors that may be attractive to those with color blindness, is also available: 0° to 5° (blue), 5° to 10° (darker blue), 10° to 15° (yellow), and >15° (red). The map covers the region from latitude 85°S to the pole on the rim of Shackleton crater. Slope data are overlain on a derived hillshade with solar azimuth 45°W and solar elevation 45°.A product of the Exploration Science Summer Intern Program: Harish, Venkata Satya Kumar Animireddi, Natasha Barrett, Sarah Boazman, Aleksandra Gawronska, Cosette Gilmour, Samuel Halim, Kathryn McCanaan, Jahnavi Shah, and David Kring.Version

Slope Map between Shackleton and de Gerlache Craters, Lunar South Pole

This map is based on data collected by the Lunar Orbiter Laser Altimeter (LOLA) onboard the Lunar Reconnaissance Orbiter (LRO). The map shows slopes derived from the LOLA 5-m elevation product (NASA Goddard Space Flight Center; Smith et al., 2010; Smith et al., 2017). The slope is represented with four traditional colors 0° to 5° (bright green), 5° to 10° (dark green), 10° to 15° (yellow), and >15° (red). A second version of the map, with colors that may be attractive to those with color blindness, is also available: 0° to 5° (blue), 5° to 10° (darker blue), 10° to 15° (yellow), and >15° (red). The map covers the region between Shackleton and de Gerlache craters. Slope data are overlain on a derived hillshade with solar azimuth 45°W and solar elevation 45°.A product of the Exploration Science Summer Intern Program: Harish, Venkata Satya Kumar Animireddi, Natasha Barrett, Sarah Boazman, Aleksandra Gawronska, Cosette Gilmour, Samuel Halim, Kathryn McCanaan, Jahnavi Shah, and David Kring.Version

Nitric oxide synthases and tubal ectopic pregnancies induced by Chlamydia infection: basic and clinical insights

Human ectopic pregnancy (EP) remains a common cause of pregnancy-related first trimester death. Nitric oxide (NO) is synthesized from L-arginine by three NO synthases (NOS) in different tissues, including the Fallopian tube. Studies of knockout mouse models have improved our understanding of the function of NOS isoforms in reproduction, but their roles and specific mechanisms in infection-induced tubal dysfunction have not been fully elucidated. Here, we provide an overview of the expression, regulation and possible function of NOS isoforms in the Fallopian tube, highlighting the effects of infection-induced changes in the tubal cellular microenvironment (imbalance of NO production) on tubal dysfunction and the potential involvement of NOS isoforms in tubal EP after Chlamydia trachomatis genital infection. The non-equivalent regulation of tubal NOS isoforms during the menstrual cycle suggests that endogenous ovarian steroid hormones regulate NOS in an isoform-specific manner. The current literature suggests that infection with C. trachomatis induces an inflammatory response that eventually leads to tubal epithelial destruction and functional impairment, caused by a high NO output mediated by inducible NOS (iNOS). Therefore, tissue-specific therapeutic approaches to suppress iNOS expression may help to prevent ectopic implantation in patients with prior C. trachomatis infection of the Fallopian tube