Evaluation of the Effect of Chronic 94 GHz Exposure on Gene Expression in the Skin of Hairless Rats In Vivo.

Millimeter waves (MMW) are broadband frequencies that have recently been used in several applications in wireless communications, medical devices and nonlethal weapons [i.e., the nonlethal weapon, Active Denial Systems, (ADS) operating at 94-95 GHz, CW]. However, little information is available on their potential effects on humans. These radio-frequencies are absorbed and stopped by the first layer of the skin. In this study, we evaluated the effects of 94 GHz on the gene expression of skin cells. Two rat populations consisting of 17 young animals and 14 adults were subjected to chronic long-term 94 GHz MMW exposure. Each group of animals was divided into exposed and sham subgroups. The two independent exposure experiments were conducted for 5 months with rats exposed 3 h per day for 3 days per week to an incident power density of 10 mW/cm2, which corresponded to twice the ICNIRP limit of occupational exposure for humans. At the end of the experiment, skin explants were collected and RNA was extracted. Then, the modifications to the whole gene expression profile were analyzed with a gene expression microarray. Without modification of the animal's temperature, long-term chronic 94 GHz-MMW exposure did not significantly modify the gene expression of the skin on either the young or adult rats.

Towards Understanding Therapeutic Failures in Masquelet Surgery: First Evidence that Defective Induced Membrane Properties are Associated with Clinical Failures.

The two-stage Masquelet induced-membrane technique (IMT) consists of cement spacer-driven membrane induction followed by an autologous cancellous bone implantation in this membrane to promote large bone defect repairs. For the first time, this study aims at correlating IMT failures with physiological alterations of the induced membrane (IM) in patients. For this purpose, we compared various histological, immunohistochemical and gene expression parameters obtained from IM collected in patients categorized lately as successfully (Responders; n = 8) or unsuccessfully (Non-responders; n = 3) treated with the Masquelet technique (6 month clinical and radiologic post-surgery follow-up). While angiogenesis or macrophage distribution pattern remained unmodified in non-responder IM as compared to responder IM, we evidenced an absence of mesenchymal stem cells and reduced density of fibroblast-like cells in non-responder IM. Furthermore, non-responder IM exhibited altered extracellular matrix (ECM) remodeling parameters such as a lower expression ratio of metalloproteinase-9 (MMP-9)/tissue inhibitor of metalloproteinases (TIMP-1) mRNA as well as an important collagen overexpression as shown by picrosirius red staining. In summary, this study is the first to report evidence that IMT failure can be related to defective IM properties while underlining the importance of ECM remodeling parameters, particularly the MMP-9/TIMP-1 gene expression ratio, as early predictive biomarkers of the IMT outcome regardless of the type of bone, fracture or patient characteristics.

Transcriptomic studies and assessment of Yersinia pestis reference genes in various conditions.

Reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) is a very sensitive widespread technique considered as the gold standard to explore transcriptional variations. While a particular methodology has to be followed to provide accurate results many published studies are likely to misinterpret results due to lack of minimal quality requirements. Yersinia pestis is a highly pathogenic bacterium responsible for plague. It has been used to propose a ready-to-use and complete approach to mitigate the risk of technical biases in transcriptomic studies. The selection of suitable reference genes (RGs) among 29 candidates was performed using four different methods (GeNorm, NormFinder, BestKeeper and the Delta-Ct method). An overall comprehensive ranking revealed that 12 following candidate RGs are suitable for accurate normalization: gmk, proC, fabD, rpoD, nadB, rho, thrA, ribD, mutL, rpoB, adk and tmk. Some frequently used genes like 16S RNA had even been found as unsuitable to study Y. pestis. This methodology allowed us to demonstrate, under different temperatures and states of growth, significant transcriptional changes of six efflux pumps genes involved in physiological aspects as antimicrobial resistance or virulence. Previous transcriptomic studies done under comparable conditions had not been able to highlight these transcriptional modifications. These results highlight the importance of validating RGs prior to the normalization of transcriptional expression levels of targeted genes. This accurate methodology can be extended to any gene of interest in Y. pestis. More generally, the same workflow can be applied to identify and validate appropriate RGs in other bacteria to study transcriptional variations.

Ebola Virus RNA Stability in Human Blood and Urine in West Africa's Environmental Conditions.

We evaluated RNA stability of Ebola virus in EDTA blood and urine samples collected from infected patients and stored in West Africa's environmental conditions. In blood, RNA was stable for at least 18 days when initial cycle threshold values were <30, but in urine, RNA degradation occurred more quickly.

Time course of skin features and inflammatory biomarkers after liquid sulfur mustard exposure in SKH-1 hairless mice.

Sulfur mustard (SM) is a strong bifunctional alkylating agent that produces severe tissue injuries characterized by erythema, edema, subepidermal blisters and a delayed inflammatory response after cutaneous exposure. However, despite its long history, SM remains a threat because of the lack of effective medical countermeasures as the molecular mechanisms of these events remain unclear. This limited number of therapeutic options results in part of an absence of appropriate animal models. We propose here to use SKH-1 hairless mouse as the appropriate model for the design of therapeutic strategies against SM-induced skin toxicity. In the present study particular emphasis was placed on histopathological changes associated with inflammatory responses after topical exposure of dorsal skin to three different doses of SM (0.6, 6 and 60mg/kg) corresponding to a superficial, a second-degree and a third-degree burn. Firstly, clinical evaluation of SM-induced skin lesions using non invasive bioengineering methods showed that erythema and impairment of skin barrier increased in a dose-dependent manner. Histological evaluation of skin sections exposed to SM revealed that the time to onset and the severity of symptoms including disorganization of epidermal basal cells, number of pyknotic nuclei, activation of mast cells and neutrophils dermal invasion were dose-dependent. These histopathological changes were associated with a dose- and time-dependent increase in expression of specific mRNA for inflammatory mediators such as interleukins (IL1ß and IL6), tumor necrosis factor (TNF)-α, cycloxygenase-2 (COX-2), macrophage inflammatory proteins (MIP-1α, MIP-2 and MIP-1αR) and keratinocyte chemoattractant (KC also called CXCL1) as well as adhesion molecules (L-selectin and vascular cell adhesion molecule (VCAM)) and growth factor (granulocyte colony-stimulating factor (Csf3)). A dose-dependent increase was also noted after SM exposure for mRNA of matrix metalloproteinases (MMP9) and laminin-γ2 which are associated with SM-induced blisters formation. Taken together, our results show that SM-induced skin histopathological changes related to inflammation is similar in SKH-1 hairless mice and humans. SKH-1 mouse is thus a reliable animal model for investigating the SM-induced skin toxicity and to develop efficient treatment against SM-induced inflammatory skin lesions.

Interplay between three RND efflux pumps in doxycycline-selected strains of Burkholderia thailandensis.

BACKGROUND: Efflux systems are involved in multidrug resistance in most Gram-negative non-fermentative bacteria. We have chosen Burkholderia thailandensis to dissect the development of multidrug resistance phenotypes under antibiotic pressure. METHODOLOGY/PRINCIPAL FINDINGS: We used doxycycline selection to obtain several resistant B. thailandensis variants. The minimal inhibitory concentrations of a large panel of structurally unrelated antibiotics were determined ± the efflux pump inhibitor phenylalanine-arginine ß-naphthylamide (PAßN). Membrane proteins were identified by proteomic method and the expressions of major efflux pumps in the doxycycline selected variants were compared to those of the parental strains by a quantitative RT-PCR analysis. Doxycycline selected variants showed a multidrug resistance in two major levels corresponding to the overproduction of two efflux pumps depending on its concentration: AmrAB-OprA and BpeEF-OprC. The study of two mutants, each lacking one of these pumps, indicated that a third pump, BpeAB-OprB, could substitute for the defective pump. Surprisingly, we observed antagonistic effects between PAßN and aminoglycosides or some ß-lactams. PAßN induced the overexpression of AmrAB-OprA and BpeAB-OprB pump genes, generating this unexpected effect. CONCLUSIONS/SIGNIFICANCE: These results may account for the weak activity of PAßN in some Gram-negative species. We clearly demonstrated two antagonistic effects of this molecule on bacterial cells: the blocking of antibiotic efflux and an increase in efflux pump gene expression. Thus, doxycycline is a very efficient RND efflux pump inducer and PAßN may promote the production of some efflux pumps. These results should be taken into account when considering antibiotic treatments and in future studies on efflux pump inhibitors.

Sirtuin 1 regulates SREBP-1c expression in a LXR-dependent manner in skeletal muscle.

Sirtuin 1 (SIRT1), a NAD(+)-dependent protein deacetylase, has emerged as a main determinant of whole body homeostasis in mammals by regulating a large spectrum of transcriptional regulators in metabolically relevant tissue such as liver, adipose tissue and skeletal muscle. Sterol regulatory element binding protein (SREBP)-1c is a transcription factor that controls the expression of genes related to fatty acid and triglyceride synthesis in tissues with high lipid synthesis rates such as adipose tissue and liver. Previous studies indicate that SIRT1 can regulate the expression and function of SREBP-1c in liver. In the present study, we determined whether SIRT1 regulates SREBP-1c expression in skeletal muscle. SREBP-1c mRNA and protein levels were decreased in the gastrocnemius muscle of mice harboring deletion of the catalytic domain of SIRT1 (SIRT1(Δex4/Δex4) mice). By contrast, adenoviral expression of SIRT1 in human myotubes increased SREBP-1c mRNA and protein levels. Importantly, SREBP-1c promoter transactivation, which was significantly increased in response to SIRT1 overexpression by gene electrotransfer in skeletal muscle, was completely abolished when liver X receptor (LXR) response elements were deleted. Finally, our in vivo data from SIRT1(Δex4/Δex4) mice and in vitro data from human myotubes overexpressing SIRT1 show that SIRT1 regulates LXR acetylation in skeletal muscle cells. This suggests a possible mechanism by which the regulation of SREBP-1c gene expression by SIRT1 may require the deacetylation of LXR transcription factors.

Evaluation of normalization strategies for qPCR quantitation of intracellular viral DNA: the example of Vaccinia virus.

Quantitation of intracellular viral genomes is critical in both clinical and fundamental virology. Quantitative real time PCR (qPCR) is currently the gold standard to detect and monitor virus infections, due to its high sensitivity and reproducibility. The reliability of qPCR data depends primarily on the technical process. Normalization, which corrects inter-sample variations related to both pre-analytical and qPCR steps, is a key point of an accurate quantitation. Total DNA input and qPCR-measured standards were evaluated to normalize intracellular Vaccinia virus (VACV) genomes. Three qPCR assays targeting either a single-copy chromosomic gene, a repeated chromosomic DNA sequence, or a mitochondrial DNA sequence were compared. qPCR-measured standards, unlike total DNA input, allowed for accurate normalization of VACV genome, regardless of the cell number. Among PCR-measured standards, chromosomic DNA and mitochondrial DNA were equivalent to normalize VACV DNA and multi-copy standards displayed lower limits of quantitation than single-copy standards. The combination of two qPCR-measured standards slightly improved the reliability of the normalization. Using one or two multi-copy standards must be favored for relative quantitation of intracellular VACV DNA. This concept could be applied to other DNA viruses.

A small molecule screen in yeast identifies inhibitors targeting protein-protein interactions within the vaccinia virus replication complex.

Genetic and biochemical data have identified at least four viral proteins essential for vaccinia virus (VACV) DNA synthesis: the DNA polymerase E9, its processivity factor (the heterodimer A20/D4) and the primase/helicase D5. These proteins are part of the VACV replication complex in which A20 is a central subunit interacting with E9, D4 and D5. We hypothesised that molecules able to modulate protein-protein interactions within the replication complex may represent a new class of compounds with anti-orthopoxvirus activities. In this study, we adapted a forward duplex yeast two-hybrid assay to screen more than 27,000 molecules in order to identify inhibitors of A20/D4 and/or A20/D5 interactions. We identified two molecules that specifically inhibited both interactions in yeast. Interestingly, we observed that these compounds displayed a similar antiviral activity to cidofovir (CDV) against VACV in cell culture. We further showed that these molecules were able to inhibit the replication of another orthopoxvirus (i.e. cowpox virus), but not the herpes simplex virus type 1 (HSV-1), an unrelated DNA virus. We also demonstrated that the antiviral activity of both compounds correlated with an inhibition of VACV DNA synthesis. Hence, these molecules may represent a starting point for the development of new anti-orthopoxvirus drugs.

Mutant of Bungarus fasciatus acetylcholinesterase with low affinity and low hydrolase activity toward organophosphorus esters.

Enzymes hydrolysing highly toxic organophosphate esters (OPs) are promising alternatives to pharmacological countermeasures against OPs poisoning. Bungarus fasciatus acetylcholinesterase (BfAChE) was engineered to acquire organophosphate hydrolase (OPase) activity by reproducing the features of the human butyrylcholinesterase G117H mutant, the first mutant designed to hydrolyse OPs. The modification consisted of a triple mutation on the (122)GFYS(125) peptide segment, resulting in (122)HFQT(125). This substitution introduced a nucleophilic histidine above the oxyanion hole, and made space in that region. The mutant did not show inhibition by excess acetylthiocholine up to 80 mM. The k(cat)/K(m) ratio with acetylthiocholine was 4 orders of magnitude lower than that of wild-type AChE. Interestingly, due to low affinity, the G122H/Y124Q/S125T mutant was resistant to sub-millimolar concentrations of OPs. Moreover, it had hydrolysing activity with paraoxon, echothiophate, and diisopropyl phosphofluoridate (DFP). DFP was characterised as a slow-binding substrate. This mutant is the first mutant of AChE capable of hydrolysing organophosphates. However, the overall OPase efficiency was greatly decreased compared to G117H butyrylcholinesterase.

Encapsulated GDNF-producing C2C12 cells for Parkinson's disease: a pre-clinical study in chronic MPTP-treated baboons.

Glial cell line-derived neurotrophic factor (GDNF), a potent neurotrophic factor with restorative effects in a variety of rodent and primate models of Parkinson's disease (PD), could be of therapeutic value to PD. In this study, we show that intraventricular chronic infusion of low doses of GDNF using encapsulated genetically engineered C2C12 cells can exert: (1) transient recovery of motor deficits (hypokinesia); (2) significant protection of intrinsic striatal dopaminergic function in the immediate vicinity of the site of implantation of the capsule in the caudate nucleus, and (3) significant-long-lasting-neurotrophic properties at the nigral level with an increase volume of the cell bodies. These observations confirm the potent neurorestorative potential of GDNF in PD and the safety/efficacy of the encapsulation technology as a means to deliver in situ this neurotrophic cytokine even using an intraventricular approach.

Corticostriatopallidal neuroprotection by adenovirus-mediated ciliary neurotrophic factor gene transfer in a rat model of progressive striatal degeneration.

Ciliary neurotrophic factor (CNTF) is a potent protective factor for striatal neurons in animal models of Huntington's disease (HD). Clinical application of this potential therapeutic still requires the design and optimization of delivery systems. In the case of HD, spatial spread in the vast volume occupied by the striatum and long-term delivery of the factor are particular challenges for these systems. We explored the potential of adenovirus-mediated gene transfer to fulfill these requirements by studying the functional and anatomical effects of single-site striatal delivery of CNTF recombinant vectors in a rat model of HD. In an initial series of experiments, unilateral injections of CNTF adenovirus were performed in rats 10, 30, or 90 d before a 5 d neurotoxic treatment with systemic 3-nitropropionic acid (3NP). Preservation of striatal neurons was observed at all time points, demonstrating temporally extended neuroprotective effects of the CNTF adenovirus. In a second series of experiments, bilateral injections of CNTF adenovirus were performed in the medial aspect of the striatum 10 d before starting 3NP intoxication. Despite placement of the CNTF-producing vector outside the lateral striatal area susceptible to lesion, massive protection of corticostriatopallidal circuits was observed, associated with significant behavioral benefits. This spatial spread of neuroprotection is discussed with reference to the retrograde transport of the adenovirus vector and the anterograde transport of the transgenic CNTF. Overall, adenovirus-mediated CNTF gene transfer appears to be a potentially useful delivery system for widespread, long-term circuit neuroprotection in HD patients.