Calcium and S100B Regulation of p53-Dependent Cell Growth Arrest and Apoptosis

In glial C6 cells constitutively expressing wild-type p53, synthesis of the calcium-binding protein S100B is associated with cell density-dependent inhibition of growth and apoptosis in response to UV irradiation. A functional interaction between S100B and p53 was first demonstrated in p53-negative mouse embryo fibroblasts (MEF cells) by sequential transfection with the S100B and the temperature-sensitive p53Val135 genes. We show that in MEF cells expressing a low level of p53Val135, S100B cooperates with p53Val135 in triggering calcium-dependent cell growth arrest and cell death in response to UV irradiation at the nonpermissive temperature (37.5°C). Calcium-dependent growth arrest of MEF cells expressing S100B correlates with specific nuclear accumulation of the wild-type p53Val135 conformational species. S100B modulation of wild-type p53Val135 nuclear translocation and functions was confirmed with the rat embryo fibroblast (REF) cell line clone 6, which is transformed by oncogenic Ha-ras and overexpression of p53Val135. Ectopic expression of S100B in clone 6 cells restores contact inhibition of growth at 37.5°C, which also correlates with nuclear accumulation of the wild-type p53Val135 conformational species. Moreover, a calcium ionophore mediates a reversible G₁ arrest in S100B-expressing REF (S100B-REF) cells at 37.5°C that is phenotypically indistinguishable from p53-mediated G₁ arrest at the permissive temperature (32°C). S100B-REF cells proceeding from G₁ underwent apoptosis in response to UV irradiation. Our data support a model in which calcium signaling and S100B cooperate with the p53 pathways of cell growth inhibition and apoptosis.     

RESOLVING EVOLUTIONARY RELATIONSHIPS AMONG THE BROWN ALGAE USING CHLOROPLAST AND NUCLEAR GENES1

The brown algae are one of the largest and most important groups of primary producers in benthic coastal marine environments. Despite their biological importance, consensus regarding their taxonomic or evolutionary relationships remains elusive. Our goal was to produce a taxon‐rich two‐gene (rbcL and LSU rDNA) phylogeny. Key species were sequenced to represent each order and family in the analyses across all 19 orders and ～40 families, including selected outgroups Schizocladiophyceae and Xanthophyceae. Our results are in sharp contrast to traditional phylogenetic concepts; the Ectocarpales are not an early diverging clade, nor do the Fucales diverge early from other brown algae. Rather, Choristocarpus is sister to the remaining brown algae. Other groups traditionally considered to have primitive features are actually recently diverged lineages, turning traditional phylogenetic concepts upside down. Additionally, our results allow for the assessment, in the broadest context, of many of the historical and more recent taxonomic changes, resulting in several emended groups along with proposals for two new orders (Onslowiales, Nemodermatales) and one new family (Phaeosiphoniellaceae).     

What Makes a Protein Sequence a Prion?

Typical amyloid diseases such as Alzheimer''s and Parkinson''s were thought to exclusively result from de novo aggregation, but recently it was shown that amyloids formed in one cell can cross-seed aggregation in other cells, following a prion-like mechanism. Despite the large experimental effort devoted to understanding the phenomenon of prion transmissibility, it is still poorly understood how this property is encoded in the primary sequence. In many cases, prion structural conversion is driven by the presence of relatively large glutamine/asparagine (Q/N) enriched segments. Several studies suggest that it is the amino acid composition of these regions rather than their specific sequence that accounts for their priogenicity. However, our analysis indicates that it is instead the presence and potency of specific short amyloid-prone sequences that occur within intrinsically disordered Q/N-rich regions that determine their prion behaviour, modulated by the structural and compositional context. This provides a basis for the accurate identification and evaluation of prion candidate sequences in proteomes in the context of a unified framework for amyloid formation and prion propagation.     

Assessing Complex Emergency Management with Clinical Case-Vignettes: A Validation Study

Objective

To evaluate whether responses to dynamic case-vignettes accurately reflect actual practices in complex emergency situations. We hypothesized that when obstetricians were faced with vignette of emergency situation identical to one they previously managed, they would report the management strategy they actually used. On the other hand, there is no reason to suppose that their response to a vignette based on a source case managed by another obstetrician would be the same as the actual management.

Methods

A multicenter vignette-based study was used in 7 French maternity units. We chose the example of severe postpartum hemorrhage (PPH) to study the use of case-vignettes for assessing the management of complex situations. We developed dynamic case-vignettes describing incidents of PPH in several steps, using documentation in patient files. Vignettes described the postpartum course and included multiple-choice questions detailing proposed clinical care. Each participating obstetrician was asked to evaluate 4 case-vignettes: 2 directly derived from cases they previously managed and 2 derived from other obstetricians’ cases. We compared the final treatment decision in vignette responses to those documented in the source-case by the overall agreement and the Kappa coefficient, both for the cases the obstetricians previously managed and the cases of others.

Results

Thirty obstetricians participated. Overall agreement between final treatment decisions in case-vignettes and documented care for cases obstetricians previously managed was 82% (Kappa coefficient: 0.75, 95% CI [0.62–0.88]). Overall agreement between final treatment decisions in case-vignettes and documented care in vignettes derived from other obstetricians’ cases was only 48% (Kappa coefficient: 0.30, 95% CI [0.12–0.48]). Final agreement with documented care was significantly better for cases based on their own previous cases than for others (p<0.001).

Conclusions

Dynamic case-vignettes accurately reflect actual practices in complex emergency situations. Therefore, they can be used to assess the quality of management in these situations.     

Rhinovirus Load Is High despite Preserved Interferon-β Response in Cystic Fibrosis Bronchial Epithelial Cells

Lung disease in cystic fibrosis (CF) is often exacerbated following acute upper respiratory tract infections caused by the human rhinovirus (HRV). Pathophysiology of these exacerbations is presently unclear and may involve deficient innate antiviral or exaggerated inflammatory responses in CF airway epithelial cells. Furthermore, responses of CF cells to HRV may be adversely affected by pre-exposure to virulence factors of Pseudomonas (P.) aeruginosa, the microorganism that frequently colonizes CF airways. Here we examined production of antiviral cytokine interferon-β and inflammatory chemokine interleukin-8, expression of the interferon-responsive antiviral gene 2’-5’-oligoadenylate synthetase 1 (OAS1), and intracellular virus RNA load in primary CF (delF508 CFTR) and healthy airway epithelial cells following inoculation with HRV16. Parallel cells were exposed to virulence factors of P. aeruginosa prior to and during HRV16 inoculation. CF cells exhibited production of interferon-β and interleukin-8, and expression of OAS1 at levels comparable to those in healthy cells, yet significantly higher HRV16 RNA load during early hours post-inoculation with HRV16. In line with this, HRV16 RNA load was higher in the CFBE41o- dF cell line overexpessing delF508 CFTR, compared with the isogenic control CFBE41o- WT (wild-type CFTR). Pre-exposure to virulence factors of P. aeruginosa did not affect OAS1 expression or HRV16 RNA load, but potentiated interleukin-8 production. In conclusion, CF cells demonstrate elevated HRV RNA load despite preserved interferon-β and OAS1 responses. High HRV load in CF airway epithelial cells appears to be due to deficiencies manifesting early during HRV infection, and may not be related to interferon-β.     

Streptococcus suis Meningitis: A Systematic Review and Meta-analysis

Background

Streptococcus suis is the most common cause of meningitis in pork consuming and pig rearing countries in South-East Asia. We performed a systematic review of studies on S. suis meningitis to define the clinical characteristics, predisposing factors and outcome.

Methodology

Studies published between January 1, 1980 and August 1, 2015 were identified from main literature databases and reference lists. Studies were included if they were written in West-European languages and described at least 5 adult patients with S. suis meningitis in whom at least one clinical characteristic was described.

Findings

We identified 913 patients with S. suis meningitis included in 24 studies between 1980 and 2015. The mean age was 49 years and 581 of 711 patients were male (82%). Exposure to pigs or pork was present in 395 of 648 patients (61%) while other predisposing factors were less common. 514 of 528 patients presented with fever (97%), 429 of 451 with headache (95%), 462 of 496 with neck stiffness (93%) and 78 of 384 patients (20%) had a skin injury in the presence of pig/pork contact. The case fatality rate was 2.9% and hearing loss was a common sequel occurring in 259 of 489 patients (53%). Treatment included dexamethasone in 157 of 300 (52%) of patients and was associated with reduced hearing loss in S. suis meningitis patients included in a randomized controlled trial.

Conclusion

S. suis meningitis has a clear association with pig and pork contact. Mortality is low, but hearing loss occurs frequently. Dexamethasone was shown to reduce hearing loss.     

Improving Maternal Care through a State-Wide Health Insurance Program: A Cost and Cost-Effectiveness Study in Rural Nigeria

Background

While the Nigerian government has made progress towards the Millennium Development Goals, further investments are needed to achieve the targets of post-2015 Sustainable Development Goals, including Universal Health Coverage. Economic evaluations of innovative interventions can help inform investment decisions in resource-constrained settings. We aim to assess the cost and cost-effectiveness of maternal care provided within the new Kwara State Health Insurance program (KSHI) in rural Nigeria.

Methods and Findings

We used a decision analytic model to simulate a cohort of pregnant women. The primary outcome is the incremental cost effectiveness ratio (ICER) of the KSHI scenario compared to the current standard of care. Intervention cost from a healthcare provider perspective included service delivery costs and above-service level costs; these were evaluated in a participating hospital and using financial records from the managing organisations, respectively. Standard of care costs from a provider perspective were derived from the literature using an ingredient approach. We generated 95% credibility intervals around the primary outcome through probabilistic sensitivity analysis (PSA) based on a Monte Carlo simulation. We conducted one-way sensitivity analyses across key model parameters and assessed the sensitivity of our results to the performance of the base case separately through a scenario analysis. Finally, we assessed the sustainability and feasibility of this program’s scale up within the State’s healthcare financing structure through a budget impact analysis. The KSHI scenario results in a health benefit to patients at a higher cost compared to the base case. The mean ICER (US$46.4/disability-adjusted life year averted) is considered very cost-effective compared to a willingness-to-pay threshold of one gross domestic product per capita (Nigeria, US$ 2012, 2,730). Our conclusion was robust to uncertainty in parameters estimates (PSA: median US$49.1, 95% credible interval 21.9–152.3), during one-way sensitivity analyses, and when cost, quality, cost and utilization parameters of the base case scenario were changed. The sustainability of this program’s scale up by the State is dependent on further investments in healthcare.

Conclusions

This study provides evidence that the investment made by the KSHI program in rural Nigeria is likely to have been cost-effective; however, further healthcare investments are needed for this program to be successfully expanded within Kwara State. Policy makers should consider supporting financial initiatives to reduce maternal mortality tackling both supply and demand issues in the access to care.     

Measuring the Outcome of Biomedical Research: A Systematic Literature Review

Background

There is an increasing need to evaluate the production and impact of medical research produced by institutions. Many indicators exist, yet we do not have enough information about their relevance. The objective of this systematic review was (1) to identify all the indicators that could be used to measure the output and outcome of medical research carried out in institutions and (2) enlist their methodology, use, positive and negative points.

Methodology

We have searched 3 databases (Pubmed, Scopus, Web of Science) using the following keywords: [Research outcome* OR research output* OR bibliometric* OR scientometric* OR scientific production] AND [indicator* OR index* OR evaluation OR metrics]. We included articles presenting, discussing or evaluating indicators measuring the scientific production of an institution. The search was conducted by two independent authors using a standardised data extraction form. For each indicator we extracted its definition, calculation, its rationale and its positive and negative points. In order to reduce bias, data extraction and analysis was performed by two independent authors.

Findings

We included 76 articles. A total of 57 indicators were identified. We have classified those indicators into 6 categories: 9 indicators of research activity, 24 indicators of scientific production and impact, 5 indicators of collaboration, 7 indicators of industrial production, 4 indicators of dissemination, 8 indicators of health service impact. The most widely discussed and described is the h-index with 31 articles discussing it.

Discussion

The majority of indicators found are bibliometric indicators of scientific production and impact. Several indicators have been developed to improve the h-index. This indicator has also inspired the creation of two indicators to measure industrial production and collaboration. Several articles propose indicators measuring research impact without detailing a methodology for calculating them. Many bibliometric indicators identified have been created but have not been used or further discussed.     

FORGE Canada Consortium: Outcomes of a 2-Year National Rare-Disease Gene-Discovery Project

Inherited monogenic disease has an enormous impact on the well-being of children and their families. Over half of the children living with one of these conditions are without a molecular diagnosis because of the rarity of the disease, the marked clinical heterogeneity, and the reality that there are thousands of rare diseases for which causative mutations have yet to be identified. It is in this context that in 2010 a Canadian consortium was formed to rapidly identify mutations causing a wide spectrum of pediatric-onset rare diseases by using whole-exome sequencing. The FORGE (Finding of Rare Disease Genes) Canada Consortium brought together clinicians and scientists from 21 genetics centers and three science and technology innovation centers from across Canada. From nation-wide requests for proposals, 264 disorders were selected for study from the 371 submitted; disease-causing variants (including in 67 genes not previously associated with human disease; 41 of these have been genetically or functionally validated, and 26 are currently under study) were identified for 146 disorders over a 2-year period. Here, we present our experience with four strategies employed for gene discovery and discuss FORGE’s impact in a number of realms, from clinical diagnostics to the broadening of the phenotypic spectrum of many diseases to the biological insight gained into both disease states and normal human development. Lastly, on the basis of this experience, we discuss the way forward for rare-disease genetic discovery both in Canada and internationally.     

The Calcium-Dependent Interaction between S100B and the Mitochondrial AAA ATPase ATAD3A and the Role of This Complex in the Cytoplasmic Processing of ATAD3A

S100 proteins comprise a multigene family of EF-hand calcium binding proteins that engage in multiple functions in response to cellular stress. In one case, the S100B protein has been implicated in oligodendrocyte progenitor cell (OPC) regeneration in response to demyelinating insult. In this example, we report that the mitochondrial ATAD3A protein is a major, high-affinity, and calcium-dependent S100B target protein in OPC. In OPC, ATAD3A is required for cell growth and differentiation. Molecular characterization of the S100B binding domain on ATAD3A by nuclear magnetic resonance (NMR) spectroscopy techniques defined a consensus calcium-dependent S100B binding motif. This S100B binding motif is conserved in several other S100B target proteins, including the p53 protein. Cellular studies using a truncated ATAD3A mutant that is deficient for mitochondrial import revealed that S100B prevents cytoplasmic ATAD3A mutant aggregation and restored its mitochondrial localization. With these results in mind, we propose that S100B could assist the newly synthesized ATAD3A protein, which harbors the consensus S100B binding domain for proper folding and subcellular localization. Such a function for S100B might also help to explain the rescue of nuclear translocation and activation of the temperature-sensitive p53val135 mutant by S100B at nonpermissive temperatures.The S100 proteins comprise a multigene family of low-molecular-weight EF-hand calcium binding and zinc binding proteins (5, 13, 16, 24, 33). To date, 19 different S100 proteins have been assigned to this protein family, and they show different degrees of similarity, ranging from 25 to 56% identity at the amino acid level. With S100B, S100P, and S100Z being the exceptions, the majority of the S100 genes are clustered on human chromosome 1q21 (33). Most S100 proteins serve as calcium sensor proteins that, upon activation, regulate the function and/or subcellular distribution of specific target proteins (13, 33, 47), and they are characterized by common structural motifs, including two low-affinity (K_D [equilibrium dissociation constant] of ∼10 μM to 100 μM) helix-loop-helix calcium binding domains (EF hands) that are separated by a hinge region and flanked by amino- and carboxy-terminal domains. The carboxy-terminal domain is variable among S100 proteins, and it typically is the site that is responsible for the selective interaction of each individual S100 protein with specific target proteins (30). S100 proteins are often upregulated in cancers, in inflammation, and in response to cellular stress (14, 16), suggesting that they function in cell responses to stress situations. Consistent with this hypothesis, stress situations were necessary to reveal phenotypes associated with the S100 knockout in mice (11, 14, 33, 56). Moreover, recent observations revealed a new function for the S100 protein family that included their ability to assist and regulate multichaperone complex-ligand interactions (41, 50, 51).One member of the S100 protein family, S100B, has attracted much interest in the past few years because, like other proteins implicated in neurodegeneration (e.g., amyloid, superoxide dismutase, and dual-specificity tyrosine phosphorylation-regulated kinase 1A), its gene is located within a segment of chromosome 21, which is trisomic in Down''s syndrome (DS). Its expression in the brain of mammals coincides with defined periods of central nervous system (CNS) maturation and cell differentiation (43). In oligodendrocyte progenitor cells (OPC), S100B expression is associated with differentiation, and S100B contributes to OPC differentiation in response to demyelinating insult (11). To understand the contribution of S100B to OPC differentiation, we searched for high-affinity S100B target proteins in this cell type by using far-Western analysis. A major and highly specific S100B target protein was identified, the mitochondrial ATAD3A protein.ATAD3A belongs to a new family of eukaryote-specific mitochondrial AAA⁺ ATPase proteins (17). In the human genome, two genes, Atad3A and Atad3B, are located in tandem on chromosome 1p36.33. The Atad3A gene is ubiquitous among multicellular organisms but absent in yeast. The Atad3B gene is specific to the human genome (27). ATAD3A is a mitochondrial protein anchored into the mitochondrial inner membrane (IM) at contact sites with the outer membrane (OM). Thanks to its simultaneous interaction with the two membranes, ATAD3A regulates mitochondrial dynamics at the interface between the inner and outer membranes and controls diverse cell responses ranging from mitochondrial metabolism, cell growth, and mitochondrial fission 20a, 25). The ATAD3A protein has also been identified as a mitochondrial DNA binding protein (23) and as a cell surface antigen in some human tumors (20, 21). The plasma membrane localization of ATAD3A in tumor cells is suggestive that ATAD3A mitochondrial routing can be compromised in pathological situations such as cancer. To understand the functional response resulting from the interaction between S100B and ATAD3A, we first characterized the minimal interaction domain on ATAD3A for S100B binding using thermodynamic studies of wild-type and ATAD3A variants as well as via nuclear magnetic resonance (NMR) spectroscopy techniques. These studies allowed us to further refine the consensus S100B binding motif, which is conserved in several other S100B target proteins, including the p53 protein and several newly discovered target proteins associated with the cell translational machinery. We next analyzed the cellular interaction of S100B with truncated ATAD3A mutants that harbor the S100B binding domain but that are deficient for mitochondrial import. These studies revealed that S100B could assist ATAD3A mutant proteins during cytoplasmic processing by preventing dysfunctional aggregation events. Our results are discussed in light of the possible function of S100B in assisting the cytoplasmic processing of proteins for proper folding and subcellular localization.