An Arabidopsis Rab18 GTPase promotes autophagy by tethering ATG18a to the ER in response to nutrient starvation

The expansion of autophagosomes requires a controlled association with the endoplasmic reticulum (ER). However, the mechanisms governing this process are not well defined. In plants, ATG18a plays a key role in autophagosome formation in response to stress, yet the factors regulating the process are unknown. This study finds that ATG18a acts as a downstream effector of RABC1, a member of the poorly characterized Rab18/RabC GTPase subclass in plants. Active RABC1 interacts with ATG18a on the ER, particularly under nutrient starvation. In rabc1 mutants, autophagy is compromised, especially under nutrient deprivation, affecting the ER association and expansion of ATG18a-positive autophagosomes. Furthermore, both dominant-negative and constitutively active RABC1 forms inhibit autophagy. The dominant inactive RABC1 impedes the ER association of ATG18a, whereas the constitutively active RABC1 delays ATG18a detachment from the ER. Collectively, RABC1 regulates the ER association and the subsequent detachment of ATG18a-positive autophagosomes during nutrient starvation.

Updated mortality and causes of death in 2020-2021 in people with HIV: a multicenter study in France

OBJECTIVE

The aim of this study was to assess updated mortality and causes of death in people with HIV (PWH) in France.

DESIGN AND METHODS

We analyzed all deaths in PWH followed up between January 1, 2020, and December 31, 2021, in 11 hospitals in the Paris region. We described the characteristics and causes of death among deceased PWH, and evaluated the incidence of mortality and associated risk factors using a multivariate logistic regression.

RESULTS

Of the 12 942 patients followed in 2020--2021, 202 deaths occurred. Mean annual incidence of death [95% confidence interval (95% CI)] was 7.8 per 1000 PWH (6.3-9.5). Forty-seven patients (23%) died from non-AIDS nonviral hepatitis (NANH)-related malignancies, 38 (19%) from non-AIDS infections (including 21 cases of COVID-19), 20 (10%) from AIDS, 19 (9%) from cardiovascular diseases (CVD), 17 (8.4%) from other causes, six (3%) from liver diseases, and five (2.5%) from suicides/violent deaths. The cause of death was unknown in 50 (24.7%) patients. Risks factors for death were age [adjusted odds ratio (aOR) 1.93; 1.66-2.25 by additional decade), AIDS history (2.23; 1.61-3.09), low CD4 + cell count (1.95; 1.36-2.78 for 200-500 cells/μl and 5.76; 3.65-9.08 for ≤200 versus > 500 cells/μl), and viral load more than 50 copies/ml (2.03; 1.33-3.08), both at last visit.

CONCLUSION

NANH malignancies remained in 2020-2021 the first cause of death. COVID-19 accounted for more than half of the mortality related to non-AIDS infections over the period. Aging, AIDS history, and a poorer viro-immunological control were associated with death.

Knowledge of recommended antibiotic treatments for community-acquired infections in general medical practice: a cross-sectional study in Occitanie region, France

To assess and analyse the knowledge of recommended antibiotic treatments, focusing on the appropriate drugs and treatment durations for the most common community-acquired infections in general medical practice in Occitanie region, France. A web-based survey was conducted over a 3-month period, from October, 2018 to January, 2019. All participants answered directly through the online platform. For the analysis of overtreatment risk, a score based system was adopted and two scores were produced: the duration score and the treatment score. 413 general practitioners completed the survey. The overall rate of concordance with guidelines in terms of both drug choice and treatment length was 2974/4956 (60%) answers. Diseases with at least 70% good answers included cystitis, group A streptococcal pharyngitis, and bacterial superficial skin infections. Diseases with fewer than 50% good answers included pyelonephritis, dog bite wounds, and community-acquired pneumonia in patients aged ≥ 65 years. Factors associated with the risk of overtreatment were age > 40 years, country setting and hospital employment. Knowledge of treatment durations is satisfactory with 60% of recommendations being met. However, varying levels were observed according to different diseases. This study highlighted a very high rate of adherence when recommendations were clear. In contrast, low levels of adherence were observed when recommendations were ambiguous or when conflicting guidelines existed.

Management of imported malaria in the emergency department: Adequacy compared to guidelines, and impact of the SARS-CoV-2 pandemic

OBJECTIVES

Adequacy of imported malaria management with respect to guidelines in emergency departments (ED) is low. We aimed to identify factors associated with this non-compliance, and a potential impact of the SARS-CoV-2 pandemic.

PATIENTS AND METHODS

Patients presenting with imported malaria at the ED of the hospital of Melun (France), from January 1, 2017 to February 14, 2022 were retrospectively included.

RESULTS

Among 205 adults and 25 children, biological criteria of severity were fully assessed in 10% of cases; lactates (40%) and blood pH (21%) levels were the main missing variables. Of 74 patients (32%) with severe malaria, 13 were misclassified as uncomplicated malaria. The choice and dosage of treatment were adequate in 85% and 92% of cases, respectively. Treatment conformity was lower in severe malaria cases than in non-severe malaria cases (OR 0.15 [95% CI 0.07-0.31]), with oral treatment in 17 patients with severe malaria; conformity was higher in the intensive care unit (OR 4.10 [95% CI 1.21-13.95]). Patients with severe malaria were more likely to start treatment within 6hours than patients with uncomplicated malaria (OR 1.97 [95% CI 1.08-3.43]), as were patients infected by P.falciparum compared to other species (OR 4.63 [95% CI 1.03-20.90]). Consulting during the SARS-CoV-2 pandemic was the only organizational factor associated with a lower probability of adequate management (OR 0.42 [95% CI 0.23-0.75]).

CONCLUSION

Initial evaluation of malaria severity and time to treatment administration could be improved. These have been adversely impacted by the SARS-CoV-2 pandemic.

Structural insights into the interactions of glutathione transferases with a nitric oxide carrier and sodium nitroprusside

Glutathione transferases are detoxification enzymes with multifaceted roles, including a role in the metabolism and scavenging of nitric oxide (NO) compounds in cells. Here, we explored the ability of Trametes versicolor glutathione transferases (GSTs) from the Omega class (TvGSTOs) to bind metal-nitrosyl compounds. TvGSTOs have been studied previously for their ligandin role and are interesting models to study protein‒ligand interactions. First, we determined the X-ray structure of the TvGSTO3S isoform bound to the dinitrosyl glutathionyl iron complex (DNGIC), a physiological compound involved in the storage of nitric oxide. Our results suggested a different binding mode compared to the one previously described in human GST Pi 1 (GSTP1). Then, we investigated the manner in which TvGSTO3S binds three nonphysiological metal-nitrosyl compounds with different metal cores (iron, ruthenium and osmium). We assayed sodium nitroprusside, a well-studied vasodilator used in cases of hypertensive crises or heart failure. Our results showed that the tested GST can bind metal-nitrosyls at two distinct binding sites. Thermal shift analysis with six isoforms of TvGSTOs identified TvGSTO6S as the best interactant. Using the Griess method, TvGSTO6S was found to improve the release of nitric oxide from sodium nitroprusside in vitro, whereas the effects of human GST alpha 1 (GSTA1) and GSTP1 were moderate. Our results open new structural perspectives for understanding the interactions of glutathione transferases with metal-nitrosyl compounds associated with the biochemical mechanisms of NO uptake/release in biological systems.

Prescription of antibiotics by general practitioners in patients with a diagnosis of SARS- CoV-2 infection: analysis of an electronic French health record

OBJECTIVE

To define the factors associated with overprescription of antibiotics by general practitioners for patients diagnosed with COVID-19 during the first wave.

METHODS

Anonymized electronic prescribing records of 1370 physicians were analyzed. Diagnosis and prescriptions were retrieved. The initiation rate by physician for 2020 was compared to 2017-2019. Prescribing habits of physicians who initiated antibiotics for more than 10% of COVID-19 patients were compared to those who did not. Regional differences in prescribing habits of physicians who have seen at least one COVID-19 patient were also analyzed.

RESULTS

For the March-April 2020 period, physicians who initiated antibiotics for more than 10% of COVID-19 patients had more consultations than those who did not. They also prescribed antibiotics more frequently for non-COVID-19 patients consulting with rhinitis. They also prescribed broad-spectrum antibiotics more frequently for treatment of cystitis. Finally, doctors in Île-de-France region saw more COVID-19 patients and initiated antibiotics more frequently. General Practitioners in southern France had a higher but non-significant ratio of azithromycin initiation rate over total antibiotics initiation rate.

CONCLUSION

We identified a subset of physicians with overprescribing profile not only for COVID-19 but also for other viral infection, and also with a tendency to prescribe broad spectrum antibiotics for a long duration. There were also regional differences concerning antibiotics initiation rate and the ratio of azithromycin prescribed. It will be necessary to evaluate the evolution of prescribing practices during subsequent waves.

Factors associated with delay in seeking healthcare for imported malaria: a retrospective study in a French hospital

BACKGROUND

Delayed treatment is associated with a higher risk of severe malaria. In malaria-endemic areas, the main factors associated with delay in seeking healthcare are low educational level and traditional beliefs. In imported malaria, determinants of delay in seeking healthcare are currently unknown.

METHODS

We studied all patients presenting with malaria from January 1st, 2017, to February 14, 2022, in the hospital of Melun, France. Demographic and medical data were recorded for all patients, and socio-professional data in a subgroup of hospitalized adults. Relative-risks and 95% confidence intervals were determined using univariate analysis by cross-tabulation.

RESULTS

234 patients were included, all travelling from Africa. Among them, 218 (93%) were infected with P. falciparum, 77 (33%) had severe malaria, 26 (11%) were younger than 18 years old, and 81 were included during the SARS-CoV-2 pandemic. There were 135 hospitalized adults (58% of all patients). The median time to first medical consultation (TFMC), defined by the period from onset of symptoms to first medical advice, was 3 days [IQR 1-5]. A TFMC ≥3 days tended to be more frequent in travellers visiting friends and relatives (VFR) (RR 1.44, 95% CI [1.0-2.05], p = 0.06), while it was less frequent in children and teenagers (RR 0.58, 95% CI [0.39-0.84], p = 0.01). Gender, African background, unemployment, living alone, and absence of referring physician were not associated with delay in seeking healthcare. Consulting during the SARS-CoV-2 pandemic was not associated with a longer TFMC, nor with a higher rate of severe malaria.

CONCLUSION

In contrast to an endemic area, socio-economic factors did not impact on delay in seeking healthcare in imported malaria. Prevention should focus on VFR subjects, who tend to consult later than other travellers.

Vaccinostewardship en Institut de formations en soins infirmiers, audit qualitatif des motivations et freins associés à la vaccination au covid 19

Introduction

Les infirmiers sont trois fois plus nombreux que les médecins en France, leurs participations aux programme de vaccinations est un enjeux clés de ces campagnes.

L'objectif de ce travail est d'évaluer la position des infirmiers en fin de formations par rapports à la vaccination aux covid 19 en terme de motivations et de freins.

Matériels et méthodes

Un sondages anonymisé et électronique sur internet a été envoyé par un des chargés de formation au sein d'un IFSI aux étudiants de deuxième et troisième années. Le premier envoi a eu lieu début janvier 2022, et deux autres rappels ont suivis, à une semaine d'écarts.

Résultats

Les répondants 69 personnes sur 113 sollicités (61 %), 24 ans en moyenne, 60/69 femmes, 46/69(67 %) déjà infectés par le covid 19.

21/69(30 %) étudiants avaient un proche présentant des co-morbidités pouvant entraîner une COVID sévère.

Concernant la vaccination contre les maladies infectieuses en général, les étudiants se considéraient comme, très favorable pour 15/69(22 %), favorable pour 37/69(54 %), modéré pour 12/69(17 %), peu favorable pour 3/69(4 %), défavorable pour 1/69(1 %), réfractaire pour 2/69(3 %)

47/69(68 %) n'était pas vacciné contre la grippe, 8/69(12 %) n'était pas à jour pour leur vaccination et rappel du covid 19.

La raison la plus importante pour se faire vacciner contre le covid 19 était pour :

- 21/69(30 %) pour protéger leurs familles.

- 19/69(28 %) pour contribuer à sortir de la pandémie de manière collective.

-16/69(23 %) par obligation pour travailler à l'hôpital.

- 9/69(13 %) se protéger.

- 3/69(4 %) pour protéger leurs patients.

Le principal frein à la vaccination contre la COVID19 était pour :

-38/69(55 %) La Peur des effets indésirables à long terme.

-15/69(25 %) La fabrication rapide des vaccins.

-5/69(7 %) Les incertitudes concernant la composition du vaccin.

-1/69(1 %) des antécédents d'allergies.

-1/69(1 %) avoir déjà eu le covid.

-1/69(1 %) ne pas croire en l'intérêt des vaccins.

-3/69(4 %) ne pas se considérer comme à risque d ‘une forme sévère.

Par ailleurs, 44/69(64 %) exprimait le souhait de bénéficier de plus de formations et d'informations sur la vaccination COVID 19 à l'IFSI ou a l'hôpital.

Conclusion

Les principales motivations des étudiants en soins infirmiers associés à la vaccination covid 19 était centrés autour du bénéfice collectif, les principaux freins étaient liés au effet a long terme et au processus de fabrication du vaccin.

Leur principale demande était de bénéficier de plus de formations et d'informations professionnelle sur la vaccination covid 19.

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Same-day discharge to home is feasible and safe in up to 75% of unselected total hip and knee arthroplasty

PURPOSE

Though numerous studies highlighted benefits of ambulatory total joint arthroplasty (TJA), most had selected patients with age and comorbidities thresholds. We aimed to report proportions of unselected TJAs that could be scheduled for and operated in ambulatory settings, and to determine factors that hinder same-day discharge (SDD).

METHODS

We studied 1100 consecutive primary TJAs (644 THAs and 456 TKAs) that were prepared following a multidisciplinary protocol for patient education and logistical preparation. Data were stratified for THA vs TKA and for success vs failure of SDD to home and multivariable analysis was performed to determine factors associated with failure of scheduled SDD to home.

RESULTS

In total, 860 (78.2%) were scheduled for ambulatory surgery, but only 819 (74.5%) achieved SDD to home; 240 (21.8%) were scheduled for non-ambulatory surgery, but 103 (9.3%) achieved SDD to rehabilitation centre. Re-operations were required in 9 (1.0%) ambulatory TJAs vs 2 (0.8%) non-ambulatory TJAs (p = 0.769), while revisions were required in 13 (1.5%) ambulatory TJAs vs 1 (0.4%) non-ambulatory TJAs (p = 0.181). Multivariable analysis confirmed that failure of SDD to home was greater for women (OR 2.59; p = 0.011) and THA (vs TKA, OR 2.41; p = 0.023).

CONCLUSION

With appropriate education and preparation, 75% of unselected primary hip and knee arthroplasties achieved SDD to home without compromising risks of complications, re-operations, or revisions. A further 9% achieved SDD to rehabilitation centre, implying that 84% of patients did not require overnight stay. These findings suggest that ambulatory surgery is feasible and safe to implement in most unselected lower limb arthroplasties.

[How I explore... macrocephaly]

Macrocephaly is a frequent reason for seeking advice in a pediatric neurology consultation. It is a non-specific neurological sign that can be isolated, be the sign of a serious acquired pathology or be part of a syndromic picture. Clinical history, physical examination and imaging are key elements of the diagnostic strategy. Signs of intracranial hypertension require an emergency work-up. Genetics, exome in particular, has enabled the characterization of various syndromes associating macrocephaly and neurodevelopmental delay. In this article, we propose an update of practices based on clinical signs.

[How I explore… autism spectrum disorder in a child]

Autism Spectrum Disorder (ASD) is a complex neurodevelopmental trouble characterized by deficits in communication and social interactions associated with restricted and repetitive behaviour, interests and activities. Given the heterogeneity of the disorder and the absence of biomarker, its diagnostic approach must be comprehensive and multidisciplinary, according to international classifications. The aetiology of ASDs remains mostly unknown and results from a multifactorial model. This document offers guidelines to standardize practices and optimize the exploration of children with autism.

[How I explore… a disorder of intellectual development in a child]

Global developmental delay (GDD) and intellectual development disorder (IDD) are common but heterogeneous pediatric conditions. Guided by a rigorous clinical and anamnestic examination, the diagnostic approach is a dynamic process which is not limited to the intelligence quotient measurement. A large panel of paraclinical tests allows etiological exploration; this generally includes biological, genetic, metabolic and iconographic examinations. To maximize therapeutic efficiency and standardize practices, this document provides a guideline for the management of pediatric GDD/IDD.

Selenium Donors at the Junction of Inflammatory Diseases

Selenium is an essential non-metal trace element, and the imbalance in the bioavailability of selenium is associated with many diseases ranking from acute respiratory distress syndrome, myocardial infarction and renal failure (Se overloading) to diseases associated with chronic inflammation like inflammatory bowel diseases, rheumatoid arthritis, and atherosclerosis (Se unload). The only source of selenium is the diet (animal and cereal sources) and its intestinal absorption is limiting for selenocysteine and selenomethionine synthesis and incorporation in selenoproteins. In this review, after establishing the link between selenium and inflammatory diseases, we envisaged the potential of selenium nanoparticles and organic selenocompounds to compensate the deficit of selenium intake from the diet. With high selenium loading, nanoparticles offer a low dosage to restore selenium bioavailability whereas organic selenocompounds can play a role in the modulation of their antioxidant or antiinflammatory activities.

[A somatic disease causing a child psychiatric disorder]

Psychiatric disorders in children may be the expression of underlying organic conditions. These are numerous and varied. The clinical presentation is often frustrating : psychiatric signs can remain isolated for years before other more specific organic signs appear. More recently, new treatments have been developed, making it possible to improve the prognosis of some of these organic diseases; screening them is therefore a daily concern for the child psychiatrist. This literature review discusses various paediatric treatable organic disorders that may have an isolated psychiatric presentation, to finally propose a decision tree algorithm based on somatic and psychiatric complaints reported.

[Periventricular nodular heterotopia : a pediatric case]

Periventricular nodular heterotopia (PVNH) is a cerebral cortex malformation, due to a deletion/duplication in the FLNA gene, located on the chromosome X. The gene is coding a cytoskeleton protein. The transmission is dominant. It enters the heterogeneous group of philaminopathies. There is a feminine predominance. Males most often show early lethality. The clinical presentation is characterised by a seizure disorder ranging from mild to intractable, a mental retardation, hypotonia, cardiovascular abnormalities, vasculopathy and/or coagulopathy leading to stroke. The surveillance must be made by a pluridisciplinary team and the genetic counseling is necessary. We present here a paediatric case.

Higher-energy collision-induced dissociation for the quantification by liquid chromatography/tandem ion trap mass spectrometry of nitric oxide metabolites coming from S-nitroso-glutathione in an in vitro model of the intestinal barrier

RATIONALE

The potency of S-nitrosoglutathione (GSNO) as a nitric oxide (NO) donor to treat cardiovascular diseases (CVDs) has been highlighted in numerous studies. In order to study its bioavailability after oral administration, which represents the most convenient route for the chronic treatment of CVDs, it is essential to develop an analytical method permitting (i) the simultaneous measurement of GSNO metabolites, i.e. nitrite, S-nitrosothiols (RSNOs) and nitrate and (ii) to distinguish them from other sources (endogenous synthesis and diet).

METHODS

Exogenous GSNO was labeled with ¹⁵ N, and the GS¹⁵ NO metabolites after conversion into the nitrite ion were derivatized with 2,3-diaminonaphthalene. The resulting 2,3-naphthotriazole was quantified by liquid chromatography/tandem ion trap mass spectrometry (LC/ITMS/MS) in multiple reaction monitoring mode after Higher-energy Collision-induced Dissociation (HCD). Finally, the validated method was applied to an in vitro model of the intestinal barrier (monolayer of Caco-2 cells) to study GS¹⁵ NO intestinal permeability.

RESULTS

A LC/ITMS/MS method based on an original transition (m/z 171 to 156) for sodium ¹⁵ N-nitrite, GS¹⁵ NO and sodium ¹⁵ N-nitrate measurements was validated, with recoveries of 100.8 ± 3.8, 98.0 ± 2.7 and 104.1 ± 3.3%, respectively. Intra- and inter-day variabilities were below 13.4 and 12.6%, and the limit of quantification reached 5 nM (signal over blank = 4). The permeability of labeled GS¹⁵ NO (10-100 μM) was evaluated by calculating its apparent permeability coefficient (P_app ).

CONCLUSIONS

A quantitative LC/ITMS/MS method using HCD was developed for the first time to selectively monitor GS¹⁵ NO metabolites. The assay allowed evaluation of GS¹⁵ NO intestinal permeability and situated this drug candidate within the middle permeability class according to FDA guidelines. In addition, the present method has opened the perspective of a more fundamental work aiming at studying the fragmentation mechanism leading to the ion at m/z 156 in HCD tandem mass spectrometry in the presence of acetonitrile.

Flush with a flash: natural three-component antimicrobial combinations based on S-nitrosothiols, controlled superoxide formation and "domino" reactions leading to peroxynitrite

S-Nitrosothiols are ˙NO releasing agents renowned for vasodilatory and antioxidant properties. O2˙- promotes their decomposition, forming highly aggressive peroxynitrite ions (ONOO-). Since the production of O2˙- can be controlled by enzymes or by visible light, such otherwise harmless components can be turned into effective antimicrobial and nematicidal combinations with numerous potential applications in medicine.

Intestinal absorption of S-nitrosothiols: Permeability and transport mechanisms

S-Nitrosothiols, a class of NO donors, demonstrate potential benefits for cardiovascular diseases. Drugs for such chronic diseases require long term administration preferentially through the oral route. However, the absorption of S-nitrosothiols by the intestine, which is the first limiting barrier for their vascular bioavailability, is rarely evaluated. Using an in vitro model of intestinal barrier, based on human cells, the present work aimed at elucidating the mechanisms of intestinal transport (passive or active, paracellular or transcellular pathway) and at predicting the absorption site of three S-nitrosothiols: S-nitrosoglutathione (GSNO), S-nitroso-N-acetyl-l-cysteine (NACNO) and S-nitroso-N-acetyl-d-penicillamine (SNAP). These S-nitrosothiols include different skeletons carrying the nitroso group, which confer different physico-chemical characteristics and biological activities (antioxidant and anti-inflammatory). According to the values of apparent permeability coefficient, the three S-nitrosothiols belong to the medium class of permeability. The evaluation of the bidirectional apparent permeability demonstrated a passive diffusion of the three S-nitrosothiols. GSNO and NACNO preferentially cross the intestinal barrier though the transcellular pathway, while SNAP followed both the trans- and paracellular pathways. Finally, the permeability of NACNO was favoured at pH 6.4, which is close to the pH of the jejunal part of the intestine. Through this study, we determined the absorption mechanisms of S-nitrosothiols and postulated that they can be administrated through the oral route.

Multiscale prediction of acoustic properties for glass wools: Computational study and experimental validation

This work is concerned with the multiscale prediction of the transport and sound absorption properties associated with industrial glass wool samples. In the first step, an experimental characterization is performed on various products using optical granulometry and porosity measurements. A morphological analysis, based on scanning electron imaging, is further conducted to identify the probability density functions associated with the fiber angular orientation. The key morphological characterization parameters of the microstructure, which serve as input parameters of the model, include the porosity, the weighted volume diameter accounting for both lengths and diameters of the analyzed fibers (and therefore the specific surface area of the random fibrous material), and the preferred out-of-plane fiber orientation generated by the manufacturing process. A computational framework is subsequently proposed and allows for the reconstruction of an equivalent fibrous network. A fully stochastic microstructural model, parameterized by the probability laws inferred from the database, is also proposed herein. Multiscale simulations are carried out to estimate transport properties and sound absorption. With no adjustable parameter, the results accounting for ten different samples obtained with various processing parameters are finally compared with the experimental data and used to assess the relevance of the reconstruction procedures and the multiscale computations.

Glutathione: Antioxidant Properties Dedicated to Nanotechnologies

Which scientist has never heard of glutathione (GSH)? This well-known low-molecular-weight tripeptide is perhaps the most famous natural antioxidant. However, the interest in GSH should not be restricted to its redox properties. This multidisciplinary review aims to bring out some lesser-known aspects of GSH, for example, as an emerging tool in nanotechnologies to achieve targeted drug delivery. After recalling the biochemistry of GSH, including its metabolism pathways and redox properties, its involvement in cellular redox homeostasis and signaling is described. Analytical methods for the dosage and localization of GSH or glutathiolated proteins are also covered. Finally, the various therapeutic strategies to replenish GSH stocks are discussed, in parallel with its use as an addressing molecule in drug delivery.

Systems toxicology meta-analysis of in vitro assessment studies: biological impact of a candidate modified-risk tobacco product aerosol compared with cigarette smoke on human organotypic cultures of the aerodigestive tract

Systems biology combines comprehensive molecular analyses with quantitative modeling to understand the characteristics of a biological system as a whole. Leveraging a similar approach, systems toxicology aims to decipher complex biological responses following exposures. This work reports a systems toxicology meta-analysis in the context of in vitro assessment of a candidate modified-risk tobacco product (MRTP) using three human organotypic cultures of the aerodigestive tract (buccal, bronchial, and nasal epithelia). Complementing a series of functional measures, a causal network enrichment analysis of transcriptomic data was used to compare quantitatively the biological impact of aerosol from the Tobacco Heating System (THS) 2.2, a candidate MRTP, with 3R4F cigarette smoke (CS) at similar nicotine concentrations. Lower toxicity was observed in all cultures following exposure to THS2.2 aerosol compared with 3R4F CS. Because of their morphological differences, a smaller exposure impact was observed in the buccal (stratified epithelium) compared with the bronchial and nasal (pseudostratified epithelium). However, the causal network enrichment approach supported a similar mechanistic impact of CS across the three cultures, including the impact on xenobiotic, oxidative stress, and inflammatory responses. At comparable nicotine concentrations, THS2.2 aerosol elicited reduced and more transient effects on these processes. To demonstrate the benefits of additional data modalities, we employed a newly established targeted mass-spectrometry marker panel to further confirm the reduced cellular stress responses elicited by THS2.2 aerosol compared with 3R4F CS in the nasal culture. Overall, this work demonstrates the applicability and robustness of the systems toxicology approach for in vitro inhalation toxicity assessment.

[Dystonia 12: A rare and difficult diagnosis]

We report a case of dystonia 12, also called rapid-onset dystonia-parkinsonism, which occurred in a young 12-year-old boy. Type 12 dystonia is a genetic syndrome characterized by a pathogenic mutation on ATP1A3 gene encoding the subunit alpha 3 of Na-K-ATPase protein, resulting in neuronal dysfunctions. It remains a rare syndrome with less than 100 cases described in the literature. Its atypical presentation and its rarity may lead to a wandering diagnosis, even in some cases to a conversion hysteria diagnosis. Today, unfortunately, there is no effective treatment.

Reduced Activity of the Aortic Gamma-Glutamyltransferase Does Not Decrease S-Nitrosoglutathione Induced Vasorelaxation of Rat Aortic Rings

Aims: Gamma-glutamyl transferase (GGT), an enzyme present on the endothelium, is involved in the release of nitric oxide (NO) from S-nitrosoglutathione (GSNO) and in the GSNO-induced vasodilation. Endogenous GSNO is a physiological storage form of NO in tissues while exogenous GSNO is an interesting candidate for compensating for the decreased NO bioavailability occurring during cardiovascular diseases. We investigated in a rat model of human hypertension, the spontaneous hypertensive rat (SHR), submitted or not to high salt diet, whether a decreased vascular GGT activity modifies the vasorelaxant effect of GSNO.

Methods: Thoracic aortic rings isolated from male SHR and Wistar Kyoto rats (WKY) aged 20–22 weeks—submitted or not for 8 weeks to a high salt diet (1% w/v NaCl in drinking water) were pre-constricted with phenylephrine then submitted to concentration-vasorelaxant response curves (maximal response: E_max; pD₂) to carbachol or sodium nitroprusside to evaluate endothelial dependent or independent NO-induced vasodilation, or GSNO (exogenous NO vasodilation depending from the endothelial GGT activity). GGT activity was measured using a chromogenic substrate in aortic homogenates. Its role in GSNO-induced relaxation was assessed following inhibition of the enzyme activity (serine-borate complex). That of protein disulfide isomerase (PDI), another redox sensitive enzyme involved in GSNO metabolism, was assessed following inhibition with bacitracin.

Results: Aortic GGT activity (18–23 μmol/min/mg of tissue in adult WKY) decreased by 33% in SHR and 45% in SHR with high salt diet. E_max and pD₂ for sodium nitroprusside were similar in all groups. E_max for carbachol decreased by −14%, reflecting slight endothelial NO-dependent dysfunction. The GSNO curve was slightly shifted to the left in SHR and in SHR with high salt diet, showing a small enhanced sensitivity to GSNO. Involvements of GGT, as that of PDI, in the GSNO effects were similar in all groups (pD₂ for GSNO −0.5 to −1.5 following enzymatic inhibition).

Conclusion: Hypertension is associated with a decreased aortic GGT activity without decreasing the vasorelaxant effects of GSNO, whose bioactivity may be supplemented through the alternative enzymatic activity of PDI.

Elaboration of Sterically Stabilized Liposomes for S-Nitrosoglutathione Targeting to Macrophages

S-nitrosoglutathione (GSNO) is a potential therapeutic for infectious disease treatment because of its pivotal role in macrophage-mediated inflammatory responses and host defense in addition to direct antibacterial activities. In this study, sterically stabilized cationic liposomes (SSCL) and sterically stabilized anionic liposomes (SSAL) were developed as nanocarriers for macrophage targeting. Elaborated liposomes were characterized in terms of size, zeta potential, morphology, encapsulation efficiency, in vitro drug release behavior and cytotoxicity. Their versatility in targeting monocytes/macrophages was determined by confocal laser scanning microscopy and transmission electron microscopy. Flow cytometry revealed that cellular uptake of both SSCL and SSAL was governed by several endocytic clathrin- and caveolae-dependent mechanisms. Quantitative assessments of intracellular nitric oxide demonstrated highly efficient uptake of GSNO-loaded SSCL that was twenty-fold higher than that of GSNO-free molecules. GSNO-loaded SSCL displayed strong bacteriostatic effects on Staphylococcus aureus and Pseudomonas aeruginosa, which can be involved in pulmonary infectious diseases. These results reveal the potential of liposomal GSNO as an anti-infective therapeutic due to its macrophage targeting capacity and direct antibacterial effects.

Structure and Stability Studies of Pharmacologically Relevant S-Nitrosothiols: A Theoretical Approach

Nowadays, S-nitrosothiols (RSNOs) represent a promising class of nitric oxide (NO) donors that could be successfully used as drugs to compensate the decrease of NO production that usually arises in conjunction with cardiovascular diseases. Nevertheless, notwithstanding their pharmacological interest, the structure-stability relationship in RSNOs is still unclear, and this issue, together with the mechanism of NO donation in the physiological medium, deserves further investigation. As a first step forward in this direction, in this paper, the overall stability and structural preference of two pharmacologically relevant S-nitrosothiol molecules were studied in detail by means of computational strategies. In particular, performing calculations in implicit solvent (water) on the S-nitroso-N-acetylpenicillamine and the S-nitroso-N-acetylcysteine and analyzing the noncovalent interactions networks of their most stable conformers, we observed that the structure and the stability of these molecules can be directly related to the formation of stabilizing hydrogen-bond and chalcogen-chalcogen intramolecular interactions. The obtained results represent the starting point for further investigations to be conducted also on larger RSNOs to shed further light on the role played by intra- and intermolecular interactions and by solvation effects in stabilizing this class of molecules. The obtained insights will be hopefully helpful to design new RSNO-based drugs characterized by an enhanced pharmacological potency.

Sulfur Denitrosylation by an Engineered Trx-like DsbG Enzyme Identifies Nucleophilic Cysteine Hydrogen Bonds as Key Functional Determinant

Exposure of bacteria to NO results in the nitrosylation of cysteine thiols in proteins and low molecular weight thiols such as GSH. The cells possess enzymatic systems that catalyze the denitrosylation of these modified sulfurs. An important player in these systems is thioredoxin (Trx), a ubiquitous, cytoplasmic oxidoreductase that can denitrosylate proteins in vivo and S-nitrosoglutathione (GSNO) in vitro However, a periplasmic or extracellular denitrosylase has not been identified, raising the question of how extracytoplasmic proteins are repaired after nitrosative damage. In this study, we tested whether DsbG and DsbC, two Trx family proteins that function in reducing pathways in the Escherichia coli periplasm, also possess denitrosylating activity. Both DsbG and DsbC are poorly reactive toward GSNO. Moreover, DsbG is unable to denitrosylate its specific substrate protein, YbiS. Remarkably, by borrowing the CGPC active site of E. coli Trx-1 in combination with a T200M point mutation, we transformed DsbG into an enzyme highly reactive toward GSNO and YbiS. The pKa of the nucleophilic cysteine, as well as the redox and thermodynamic properties of the engineered DsbG are dramatically changed and become similar to those of E. coli Trx-1. X-ray structural insights suggest that this results from a loss of two direct hydrogen bonds to the nucleophilic cysteine sulfur in the DsbG mutant. Our results highlight the plasticity of the Trx structural fold and reveal that the subtle change of the number of hydrogen bonds in the active site of Trx-like proteins is the key factor that thermodynamically controls reactivity toward nitrosylated compounds.