Knockdown of regulatory associated protein of TOR (raptor) in hypothalamus-stimulated folliculogenesis and induced ovarian cysts

CONTEXT

Mammalian target of rapamycin complex 1 (mTORC1) is an essential sensor that regulates fundamental biological processes like cell growth, proliferation and energy metabolism. The treatment of disease by sirolimus, a mTORC1 inhibitor, causes adverse effects, such as female fertility disorders.

AIMS

The objective of the study was to decipher the reproductive consequences of a downregulation of mTORC1 in the hypothalamus.

METHODS

The reduced expression of mTORC1 was induced after intracerebroventricular injection of lentivirus expressing a short hairpin RNA (shRNA) against regulatory associated protein of TOR (raptor) in adult female mice (ShRaptor mice).

KEY RESULTS

The ShRaptor mice were fertile and exhibited a 15% increase in the litter size compared with control mice. The histological analysis showed an increase in antral, preovulatory follicles and ovarian cysts. In the hypothalamus, the GnRH mRNA and FSH levels in ShRaptor mice were significantly elevated.

CONCLUSIONS

These results support the hypothesis that mTORC1 in the central nervous system participates in the regulation of female fertility and ovarian function by influencing the GnRH neuronal activity.

IMPLICATIONS

These results suggest that a lower mTORC1 activity directly the central nervous system leads to a deregulation in the oestrous cycle and an induction of ovarian cyst development.

Chicken cGAS Senses Fowlpox Virus Infection and Regulates Macrophage Effector Functions

The anti-viral immune response is dependent on the ability of infected cells to sense foreign nucleic acids. In multiple species, the pattern recognition receptor (PRR) cyclic GMP-AMP synthase (cGAS) senses viral DNA as an essential component of the innate response. cGAS initiates a range of signaling outputs that are dependent on generation of the second messenger cGAMP that binds to the adaptor protein stimulator of interferon genes (STING). Here we show that in chicken macrophages, the cGAS/STING pathway is essential not only for the production of type-I interferons in response to intracellular DNA stimulation, but also for regulation of macrophage effector functions including the expression of MHC-II and co-stimulatory molecules. In the context of fowlpox, an avian DNA virus infection, the cGAS/STING pathway was found to be responsible for type-I interferon production and MHC-II transcription. The sensing of fowlpox virus DNA is therefore essential for mounting an anti-viral response in chicken cells and for regulation of a specific set of macrophage effector functions.

Major contribution of the RNA-binding domain of NS1 in the pathogenicity and replication potential of an avian H7N1 influenza virus in chickens

Background

Non-structural protein NS1 of influenza A viruses harbours several determinants of pathogenicity and host-range. However it is still unclear to what extent each of its two structured domains (i.e. RNA-binding domain, RBD, and effector domain, ED) contribute to its various activities.

Methods

To evaluate the respective contributions of the two domains, we genetically engineered two variants of an H7N1 low pathogenicity avian influenza virus harbouring amino-acid substitutions that impair the functionality of either domain. The RBD- and ED-mutant viruses were compared to their wt- counterpart in vivo and in vitro, notably in chicken infection and avian cell culture models.

Results

The double substitution R38A-K41A in the RBD dramatically reduced the pathogenicity and replication potential of the virus, whereas the substitution A149V that was considered to abrogate the IFN-antagonistic activity of the effector domain entailed much less effects. While all three viruses initiated the viral life cycle in avian cells, replication of the R38A-K41A virus was severely impaired. This defect was associated with a delayed synthesis of nucleoprotein NP and a reduced accumulation of NS1, which was found to reach a concentration of about 30 micromol.L^− 1 in wt-infected cells at 8 h post-infection. When overexpressed in avian lung epithelial cells, both the wt-NS1 and 3841AA-NS1, but not the A149V-NS1, reduced the poly(I:C)-induced activation of the IFN-sensitive chicken Mx promoter. Unexpectedly, the R38A-K41A substitution in the recombinant RBD did not alter its in vitro affinity for a model dsRNA. When overexpressed in avian cells, both the wt- and A149V-NS1s, as well as the individually expressed wt-RBD to a lesser extent, enhanced the activity of the reconstituted viral RNA-polymerase in a minireplicon assay.

Conclusions

Collectively, our data emphasized the critical importance and essential role of the RNA-binding domain in essential steps of the virus replication cycle, notably expression and translation of viral mRNAs.

The impact of school-organized sport activities on the priority youth health-risk behaviors

PURPOSE: To evaluate the impact of school-organized sport activities on the priority youth health-risk behaviors.METHODS: Data were taken from The 1997 National School-based Youth Risk Behavior Survey. Measures of prevalence rates in six categories of priority health-risk behaviors defined by Centers for Disease Control and Prevention were performed between participants and non-participants in school-organized sport activities. Then multiple logistic regression analyses were used to assess the association between participation in school-organized sport activities and the priority health-risk behaviors.RESULTS: Overall, 49.5% of students nationwide participated in school-organized sport activities in 1997. The major behavioral factors that proved statistically significant in predicting participation in school-organized activities in the logistic regression model were non-use of seatbelt, non-use of helmet, and use of chewing tobacco. Behavioral factors that were inversely related to participation in school-organized activities were smoking cigarettes, using different kinds of drugs, using condoms, carrying weapons, eating vegetables, and attempting suicide.CONCLUSIONS: Based on the nationally representative data, participation in school-organized sport activities was positively associated with many desirable health behaviors. However, a challenge for us will be not only to promote youth participation in school-organized sport activities, but also to address some co-existing behavioral problems that may lead to non-intentional injury and use of chewing tobacco.

The effects of sprue design on the roughness and porosity of titanium castings

PURPOSE

This study measured the effects of the sprue number and position on the roughness and porosity of cast titanium crowns.

MATERIAL AND METHODS

Twenty-four complete veneer crown wax patterns were fabricated on a stainless steel die with a 30-degree bevel finish line. Twelve wax patterns were sprued with one 8-gauge wax sprue and the remaining 12 were double sprued. All patterns were invested with a phosphate bonded investment. Castings were made with a titanium casting, according to the manufacturer's instructions, with commercially pure titanium (> 99.5%) ingots. The castings were carefully cleaned and the surface roughness was measured with a profilometer. The specimens were then embedded and sectioned. Internal porosities were quantified with photographs by computerized image analysis. Data were analyzed with an ANOVA and the Student's t test with a confidence level of 95%.

RESULTS

The roughness value of the occlusal third of the crowns for the single sprue group (Ra = 3.0 +/- 0.9 microns) was significantly higher than other measurements (p < 0.05). There were statistically significant differences in values of porosity areas between the single sprue group (1.5 +/- 0.7 mm2) and the double sprue group (0.2 +/- 0.2 mm2) (p < 0.01). The double sprue design resulted in a relatively smoother casting surface and less internal porosity than the single sprue design.

CONCLUSIONS

Improvements in the degree of roughness and porosity of titanium crown castings were the result of the double sprue design.