DPCD is a regulator of R2TP in ciliogenesis initiation through Akt signaling

R2TP is a chaperone complex consisting of the AAA+ ATPases RUVBL1 and RUVBL2, as well as RPAP3 and PIH1D1 proteins. R2TP is responsible for the assembly of macromolecular complexes mainly acting through different adaptors. Using proximity-labeling mass spectrometry, we identified deleted in primary ciliary dyskinesia (DPCD) as an adaptor of R2TP. Here, we demonstrate that R2TP-DPCD influences ciliogenesis initiation through a unique mechanism by interaction with Akt kinase to regulate its phosphorylation levels rather than its stability. We further show that DPCD is a heart-shaped monomeric protein with two domains. A highly conserved region in the cysteine- and histidine-rich domains-containing proteins and SGT1 (CS) domain of DPCD interacts with the RUVBL2 DII domain with high affinity to form a stable R2TP-DPCD complex both in cellulo and in vitro. Considering that DPCD is one among several CS-domain-containing proteins found to associate with RUVBL1/2, we propose that RUVBL1/2 are CS-domain-binding proteins that regulate complex assembly and downstream signaling.

The place of the relative at the time of the announcement of cancer progression: BABEL - a mixed-methods study

OBJECTIVES

This study aims to explore the place of the relative in these triadic consultations and how this influences communication.

METHODS

A mixed-methods research strategy was used. Triadic consultations for the announcement of cancer progression were recorded and following the 3 participants completed questionnaires comprising mirror-items. Recordings and answers were further investigated in a few semi-structured interviews. Comparison of quantitative responses (questionnaires) used Wilcoxon's test for matched series. Qualitative analyses (consultations, interviews) used grounded theory. Patients were over 18, followed for cancer in palliative phase, excluding brain tumors and malignant hemopathies, and presented renewed disease progression. Relatives were over 18 and authorized by the patient to participate.

RESULTS

47 consultations (audio-recordings, answers to questionnaires) and 12 interviews conducted separately with 4 triads were collected. Half the relatives, while remaining in the background, nevertheless contributed to the discussion. For patients, the presence of a relative was considered beneficial and for oncologists it facilitated the announcement. However, symptoms perceived as intimate or private appeared difficult to express for some patients, and for relatives, prognosis was a difficult subject to broach. Although their relationship with time and their expectations may differ, patients and relatives found consultations positive. Oncologists appeared to underestimate the patient's level of understanding (P<0.001) and perceptions of the seriousness of the disease (P=0.009) but not those of relatives. They did not evaluate the relative's state of health and check what the dyad had retained.

SIGNIFICANCE OF RESULTS

Training via simulation sessions should be adapted to communication involving relatives.

Astrocytes express aberrant immunoglobulins as putative gatekeeper of astrocytes to neuronal progenitor conversion

Using multi-omics analyses including RNAseq, RT-PCR, RACE-PCR, and shotgun proteomic with enrichment strategies, we demonstrated that newborn rat astrocytes produce neural immunoglobulin constant and variable heavy chains as well as light chains. However, their edification is different from the ones found in B cells and they resemble aberrant immunoglobulins observed in several cancers. Moreover, the complete enzymatic V(D)J recombination complex has also been identified in astrocytes. In addition, the constant heavy chain is also present in adult rat astrocytes, whereas in primary astrocytes from human fetus we identified constant and variable kappa chains as well as the substitution lambda chains known to be involved in pre-B cells. To gather insights into the function of these neural IgGs, CRISPR-Cas9 of IgG2B constant heavy chain encoding gene (Igh6), IgG2B overexpression, proximal labeling of rat astrocytes IgG2B and targets identification through 2D gels were performed. In Igh6 KO astrocytes, overrepresentation of factors involved in hematopoietic cells, neural stem cells, and the regulation of neuritogenesis have been identified. Moreover, overexpression of IgG2B in astrocytes induces the CRTC1-CREB-BDNF signaling pathway known to be involved in gliogenesis, whereas Igh6 KO triggers the BMP/YAP1/TEAD3 pathway activated in astrocytes dedifferentiation into neural progenitors. Proximal labeling experiments revealed that IgG2B is N-glycosylated by the OST complex, addressed to vesicle membranes containing the ATPase complex, and behaves partially like CD98hc through its association with LAT1. These experiments also suggest that proximal IgG2B-LAT1 interaction occurs concomitantly with MACO-1 and C2CD2L, at the heart of a potentially novel cell signaling platform. Finally, we demonstrated that these chains are synthesized individually and associated to recognize specific targets. Indeed, intermediate filaments Eif4a2 and Pdia6 involved in astrocyte fate constitute targets for these neural IgGs. Taken together, we hypothese that neural aberrant IgG chains may act as gatekeepers of astrocytes' fate.

Human Papillomavirus 42 Drives Digital Papillary Adenocarcinoma and Elicits a Germ Cell-like Program Conserved in HPV-Positive Cancers

The skin is exposed to viral pathogens, but whether they contribute to the oncogenesis of skin cancers has not been systematically explored. Here we investigated 19 skin tumor types by analyzing off-target reads from commonly available next-generation sequencing data for viral pathogens. We identified human papillomavirus 42 (HPV42) in 96% (n = 45/47) of digital papillary adenocarcinoma (DPA), an aggressive cancer occurring on the fingers and toes. We show that HPV42, so far considered a nononcogenic, "low-risk" HPV, recapitulates the molecular hallmarks of oncogenic, "high-risk" HPVs. Using machine learning, we find that HPV-driven transformation elicits a germ cell-like transcriptional program conserved throughout all HPV-driven cancers (DPA, cervical carcinoma, and head and neck cancer). We further show that this germ cell-like transcriptional program, even when reduced to the top two genes (CDKN2A and SYCP2), serves as a fingerprint of oncogenic HPVs with implications for early detection, diagnosis, and therapy of all HPV-driven cancers.

SIGNIFICANCE

We identify HPV42 as a uniform driver of DPA and add a new member to the short list of tumorigenic viruses in humans. We discover that all oncogenic HPVs evoke a germ cell-like transcriptional program with important implications for detecting, diagnosing, and treating all HPV-driven cancers. See related commentary by Starrett et al., p. 17. This article is highlighted in the In This Issue feature, p. 1.

Dispersal syndromes in challenging environments: A cross-species experiment

Dispersal is a central biological process tightly integrated into life-histories, morphology, physiology and behaviour. Such associations, or syndromes, are anticipated to impact the eco-evolutionary dynamics of spatially structured populations, and cascade into ecosystem processes. As for dispersal on its own, these syndromes are likely neither fixed nor random, but conditional on the experienced environment. We experimentally studied how dispersal propensity varies with individuals' phenotype and local environmental harshness using 15 species ranging from protists to vertebrates. We reveal a general phenotypic dispersal syndrome across studied species, with dispersers being larger, more active and having a marked locomotion-oriented morphology and a strengthening of the link between dispersal and some phenotypic traits with environmental harshness. Our proof-of-concept metacommunity model further reveals cascading effects of context-dependent syndromes on the local and regional organisation of functional diversity. Our study opens new avenues to advance our understanding of the functioning of spatially structured populations, communities and ecosystems.

Entrepôts de données cliniques, outil du pilotage de crise

Introduction

La crise sanitaire COVID-19 a nécessité un suivi épidémiologique et d'activité pour adapter, en situation d'incertitude, la gestion hospitalière (capacitaire comme ressources humaines) au fil des jours. Le département de santé publique du CHRU de Tours a créé et automatisé un tableau de bord (TdB) de suivi COVID en utilisant son entrepôt de données cliniques.

Méthodes

L’équipe d’épidémiologie, en collaboration avec la cellule de crise du CHRU comprenant soignants, virologues et directeurs, a construit des indicateurs de suivi épidémique consultables dans un TdB interactif. Les données sont issues de l'entrepôt eHOP® qui intègre en temps réel les données du dossier patient informatisé : comptes rendus, biologie, prescriptions. Ces indicateurs sont mis à jour automatiquement toutes les six heures sur l'intranet du CHRU (Dashboard R Shiny®), accessible à tous les agents. L'identification des cas COVID-19+ se base sur les données virologiques et/ou déclaration de cas SI-VIC, pour les patients testés en ambulatoire. La guérison est définie par la sortie vers le domicile. En parallèle, les données départementales et régionales (data.gouv.fr : hospitalisation SI-VIC, dépistage SI-DEP, vaccination SI-VAC) ont été intégrées au TdB.

Résultats

Sont consultables à tout moment via des graphiques interactifs : l’évolution des hospitalisations COVID au sein des différents secteurs (médecine, réanimation…), les caractéristiques des patients (hospitalisés, guéris, décédés), les passages aux urgences pour suspicion COVID dont ceux ayant nécessité une hospitalisation, le nombre et taux de positivité des tests de dépistage (RTPCR, TAG) et sérologies réalisés par le laboratoire de virologie pour le CHRU et le GHT élargi. Les données de couverture vaccinale des agents y sont implémentées depuis janvier 2021. Au niveau départemental et régional sont consultables : évolution des incidences, hospitalisations (dont tension en réanimation) et couverture vaccinale en population générale, cartographies (dépistage, incidences, hospitalisations).

Discussion/Conclusion

Un TdB automatisé en temps réel permet une aide à la décision réactive en situation de crise et favorise l'information et la transmission de messages-clés aux agents (hygiène, vaccination, …).

741 Restarting Elective Orthopaedic Surgery During The COVID-19 Pandemic: Experiences and Patient Outcomes

Aim

The COVID-19 pandemic resulted in postponing all non-urgent elective surgeries from April 2020. As we emerged from the first peak, restarting non-urgent services such as elective orthopaedic surgery was important for patients with chronic debilitating conditions. Our hospital successfully restarted orthopaedic surgery during the pandemic to help improve the quality of life of patients. This study describes the development of local protocols and pathways to allow for a safe restart of elective orthopaedic surgery in a COVID-19 free site. It presents the morbidity and mortality outcomes of those patients.

Method

This is a prospective cohort study evaluating all patients undergoing non-emergency orthopaedic procedures through a COVID-19 free pathway in a DGH from 18th May – 10th July 2020. 104 patients were identified, and their outcomes analysed during the 2 weeks following their surgery.

Results

No patients developed COVID-19 in the 2-weeks post-operative period. There were no ITU admissions or in-hospital deaths. 22(21.15%) out of 104 patients developed 23 complications within 2 weeks of surgery. These included: TIA, PE, AF, superficial wound infection, oozy wound and post-operative anaemia. They all made full recovery. There was no statistical difference in the development of complications for age (&lt; 70; &gt;70), gender, BMI, or ASA grades.

Conclusions

This study describes a roadmap to setting up a protocolised elective operating service for orthopaedic surgery. It has shown that standardised protocols in a COVID-19 free site, pre-operative COVID-19 testing and adherence to national guidelines on self-isolation prior to surgery can help prevent COVID-19 infection and its related risks post-operatively.

Les entrepôts de données cliniques : un outil d’aide au pilotage de crise

Introduction

La crise sanitaire COVID-19 a nécessité la mise en place d’un suivi épidémique quotidien (épidémiologie et activité) en établissements de santé pour adapter, en situation d’incertitude, la gestion hospitalière (capacités comme ressources humaines). Le département de santé publique du CHU a créé et automatisé un tableau de bord (TdB) de suivi COVID en temps réel en utilisant son entrepôt de données cliniques.

Matériels et méthodes

Dès mars 2020, l’équipe d’épidémiologie et de santé publique, en collaboration avec la cellule de crise du CHU constituée de soignants, virologues et directeurs, a construit des indicateurs de suivi épidémique consultables dans un TdB interactif. Les données utilisées sont issues de l’entrepôt eHOP® implémenté au CHU qui intègre en temps réel les données du dossier patient informatisé : comptes rendus médicaux, biologie, prescriptions. Ces indicateurs sont automatisés et mis à jour toutes les 6 heures sur l’intranet du CHU (Dashboard R Shiny®), accessible en temps réel pour tous les agents. En parallèle, des données d’open data départementales et régionales (data.gouv.fr : hospitalisation SI-VIC, dépistage SI-DEP, vaccination SI-VAC) ont été intégrées au TdB.

Résultats

Sont consultables à tout moment via des graphiques interactifs : l’évolution des hospitalisations COVID au sein des différents secteurs (médecine dont secteur COVID ou non, réanimation, autres) ; les caractéristiques des patients hospitalisés, guéris et/ou décédés ; les passages aux urgences pour suspicion COVID, dont les cas confirmés et ceux ayant nécessité une hospitalisation ; le nombre et le taux de positivité des tests de dépistage (RT-PCR, TAG) et des sérologies réalisés par le laboratoire de virologie, que ce soit pour des personnes du CHU ou du GHT élargi. Les données de couverture vaccinale des agents du CHU par professions, ainsi que le nombre de vaccinations effectuées pour des personnes hors CHU (patients, professionnels libéraux) y sont implémentées depuis janvier 2021. Au niveau départemental et régional sont consultables : l’évolution des incidences, par âge et départements, et des hospitalisations COVID du département et de la région (dont mortalité et tension en réanimation), ainsi que des cartographies hebdomadaires sur l’activité de dépistage (taux de dépistage, de positivité, d’incidence) et hospitalière.

Conclusion

Le développement d’un TdB automatisé permet une aide à la décision de la cellule de crise du CHU par la mise à disposition en temps réel de données objectives et donc une gestion réactive et agile. L’information continue des agents favorise la transmission d’informations et de messages clés, comme la promotion de la vaccination.

643 Near-Peer Surgical Teaching for Junior Doctors: A 16-Month Retrospective Analysis

Introduction

Surgical departments across the UK are having to mitigate service demands, budget constraints and changes to work patterns with their statutory duty to provide high-quality training and education. Securing consultant-led teaching has also become increasingly difficult leading to the rise of near-peer teaching. We evaluate the long-term effectiveness of near-peer surgical teaching for junior doctors.

Method

We developed a rolling 12-week trainee-led didactic surgical education programme for Foundation doctors and Core Surgical Trainees. Junior doctors delivered teaching to peers with registrar input; session and supervision feedback was recorded using 5-point scales and free-text responses.

Results

42 junior doctors responded to our end-of-programme feedback surveys covering December 2018 to April 2020. The overall programme (8.83±1.08/10), relevance (4.62±0.58/5), presentation quality (4.60±0.50/5) and supervisor knowledge (4.81±0.40/5) were rated highly by respondents. Attendees also reported significant improvements in subject knowledge (3.72±0.92/5 to 4.50±0.56/5, P &lt; 0.0001), clinical confidence, presentation and teaching skills.

Conclusions

Our near-peer teaching programme addressed the educational needs of junior doctors and developed their presentation and organisational skills. Supervision and input from registrars facilitated discussion and reinforced key concepts. The success of this programme highlights the role that trainees can play in designing, developing, and leading an effective surgical teaching programme.

Comparative Super-Resolution Mapping of Basal Feet Reveals a Modular but Distinct Architecture in Primary and Motile Cilia

In situ molecular architecture analysis of organelles and protein assemblies is essential to understanding the role of individual components and their cellular function, and to engineering new molecular functionalities. Through a super-resolution-driven approach, here we characterize the organization of the ciliary basal foot, an appendage of basal bodies whose main role is to provide a point of anchoring to the microtubule cytoskeleton. Quantitative image analysis shows that the basal foot is organized into three main regions linked by elongated coiled-coil proteins, revealing a conserved modular architecture in primary and motile cilia, but showing distinct features reflecting its specialized functions. Using domain-specific BioID proximity labeling and super-resolution imaging, we identify CEP112 as a basal foot protein and other candidate components of this assembly, aiding future investigations on the role of basal foot across different cilia systems.

TERT Promoter Mutation as an Independent Prognostic Marker for Poor Prognosis MAPK Inhibitors-Treated Melanoma

Although the development of mitogen-activated protein kinase (MAPK) inhibitors has greatly improved the prognosis of BRAFV600 cutaneous melanomas, the identification of molecular indicators for mutated patients at risk of early progression remains a major issue. Using an amplicon-based next-generation-sequencing (NGS) assay that targets cancer-related genes, we investigated co-occurring alterations in 89 melanoma samples. We analyzed both their association with clinicopathological variables and clinical significance in terms of progression-free survival (PFS) and overall survival (OS) according to BRAF genotyping. Among co-occurring mutations, TERT promoter was the most frequently mutated gene. Although no significant difference in PFS was observed in the presence or absence of co-occurring alterations to BRAFV600, there was a trend of longer PFS for patients harboring TERT c.-124C>T mutation. Of most interest, this mutation is an independent marker of good prognosis in subgroups of patients with poor prognosis (presence of brain metastasis and elevated level of lactate dehydrogenase, LDH). Moreover, combination of elevated LDH level, presence of brain metastasis, and TERT c.-124C>T mutation was identified as the best fit model for predicting clinical outcome. Our work revealed the potential interest of c.-124C>T status determination in order to refine the prognosis of BRAFV600 melanoma under mitogen-activated protein kinase (MAPK) inhibitors.

Global Interactome Mapping of Mitochondrial Intermembrane Space Proteases Identifies a Novel Function for HTRA2

A number of unique proteases localize to specific sub-compartments of the mitochondria, but the functions of these enzymes are poorly defined. Here, in vivo proximity-dependent biotinylation (BioID) is used to map the interactomes of seven proteases localized to the mitochondrial intermembrane space (IMS). In total, 802 high confidence proximity interactions with 342 unique proteins are identified. While all seven proteases co-localized with the IMS markers OPA1 and CLPB, 230 of the interacting partners are unique to just one or two protease bait proteins, highlighting the ability of BioID to differentiate unique interactomes within the confined space of the IMS. Notably, high-temperature requirement peptidase 2 (HTRA2) interacts with eight of 13 components of the mitochondrial intermembrane space bridging (MIB) complex, a multiprotein assembly essential for the maintenance of mitochondrial cristae structure. Knockdown of HTRA2 disrupts cristae in HEK 293 and OCI-AML2 cells, and leads to increased intracellular levels of the MIB subunit IMMT. Using a cell-free assay it is demonstrated that HTRA2 can degrade recombinant IMMT but not two other core MIB complex subunits, SAMM50 and CHCHD3. The IMS protease interactome thus represents a rich dataset that can be mined to uncover novel IMS protease biology.

[Cesarean sections in the Centre-Val de Loire region: Practices and indications-the Robson Classification]

BACKGROUND

To study the cesarean section (c-section) practices in the French Centre-Val de Loire region: incidence of planned c-section and rate variations between maternities, incidence of potentially avoidable cesarean sections.

METHODS

The data were extracted from the 2016 regional birth register, which permitted classification of each planned c-section according to the pre-existing risk of c-section (high or low) as defined by the Robson classification. To enhance the data, especially the indications for c-section, which are not included in the register, a survey was conducted from September 2016 to February 2017 in all of the 20 maternities in the region.

RESULTS

In 2016, nearly 26,000 women gave birth in the CVL region, of whom 19.2% by c-section (7.0% planned c-sections). The planned c-section rate was higher for breech presentation and scarred uterus, and decreased according to level of the maternity (I 41% - II 35% - III 32%). Concerning the c-section indications, 1,979 c-sections were studied during the period (18.6% of births), including 762 planned c-sections (7.1% of births). Among them, 246 (32%) were potentially avoidable, mainly isolated indications of scarred uterus with only one previous c-section or breech presentation, and 17 due to unfavorable radiologic pelvimetry in nulliparous women.

CONCLUSION

Specific actions were identified: targeted use of radiologic pelvimetry, targeted c-section on scarred uterus with only one previous cesarean section or breech presentation, as recommended by the national guidelines. The Robson classification should be widely used to evaluate and enhance practices, in particularly through painstakingly interpreted inter-maternity comparisons.

Fragmentation mediates thermal habitat choice in ciliate microcosms

Habitat fragmentation is expected to reduce dispersal movements among patches as a result of increased inter-patch distances. Furthermore, since habitat fragmentation is expected to raise the costs of moving among patches in the landscape, it should hamper the ability or tendency of organisms to perform informed dispersal decisions. Here, we used microcosms of the ciliate Tetrahymena thermophila to test experimentally whether habitat fragmentation, manipulated through the length of corridors connecting patches differing in temperature, affects habitat choice. We showed that a twofold increase of inter-patch distance can as expected hamper the ability of organisms to choose their habitat at immigration. Interestingly, it also increased their habitat choice at emigration, suggesting that organisms become choosier in their decision to either stay or leave their patch when obtaining information about neighbouring patches gets harder. This study points out that habitat fragmentation might affect not only dispersal rate but also the level of non-randomness of dispersal, with emigration and immigration decisions differently affected. These consequences of fragmentation might considerably modify ecological and evolutionary dynamics of populations facing environmental changes.

Indications and practices of Cesarean Sections in a French region – The Robson classification

Background

Cesarian-section (CS) deliveries, although sometimes vital, are associated with increasing immediate- and long-term maternal and/or neonatal risks. The objective was to describe the indications of scheduled CS, measure the potentially avoidable CS and study the rate variations between maternities in one French region, Centre Val-de-Loire (CVL).

Methods

A cross-sectional study was conducted from September 2016 to February 2017. Information about all CS performed in the maternities of the region was collected: medical history, indication, schedule. Data collection was completed with the 2016 regional birth data repository (25,864 deliveries, including 19.2% of CS, among which 7.0% were scheduled). CS were classified according to the pre-existing risk high or low of CS as defined by the Robson classification.

Results

During the study period, 1,979 CS (18.6% of deliveries) were performed, of which 762 were scheduled (7.1% of deliveries). The main indications for planning a CS were: scarred uterus (60%, of which 56% with only one previous CS) or breech presentation (25%), considered at high risk of CS according to the Robson classification. For these two contexts, the regional birth repository showed decreasing scheduled CS rates from high to low level of maternities’ expertise. Remarkly, 22 nulliparous women with a single cephalic pregnancy in spontaneous labor before term (Robson’s low risk of CS) had a CS performed for unfavorable pelvimetry (0.2% of deliveries).

Conclusions

This study allowed identifying specific potential interventions: targeted CS on scarred uterus with only one previous CS or breech presentation, as recommended by national guidelines, and targeted use of radiologic pelvimetry. The Robson classification must be widely used to assess practices through cautious maternity comparisons to improve quality of care.

Key messages

Although potentially avoidable c-sections are rare, interventions were identified: targeted CS on uterus with one previous CS or breech presentation, targeted use of radiologic pelvimetry. The Robson classification must be widely used to assess practices, in order to improve healthcare quality.

Challenges of a French Hospital Discharge algorithm to detect non-accidental paediatric burns

Background

Child maltreatment includes physical, psychological, sexual abuse and acts of neglect. Among the resulting non-accidental injuries, burns are responsible for an important morbi-mortality. The main objective was to build a detection algorithm of non-accidental paediatric burns (NAB), using ICD-10 codes in the hospital resumes from the French Hospital Discharge Database (HDD).

Methods

Children aged 0 to 16 years old hospitalised at the University Hospital of Tours from 2012 to 2017 with a coded burn were included. “Probable” or “possible” HDD cases of NAB were defined based on specific ICD-10 codes during the inclusion stay or the previous year. A chart review was performed on all the HDD cases and HDD non cases matched on sex and age with a 1:2 ratio. Performance parameters were estimated for three clinical definitions of suspected child maltreatment: excluding neglect, including neglect with restriction then broad definition. For clinical cases, report to the judicial authority (RJA) or worrying information (WI) was searched.

Results

Among the 253 included children, 83 “probable” cases and 153 non cases were analysed. Sensitivity varied from 48% (95%CI [36-60]) to 90% [55-100] when excluding neglect, specificity from 70% [63;77] to 68% [61;74]. The positive and negative likelihood ratios varied respectively from 1,6 [1,2;2,3] to 2,8 [2,1;3,7] and from 0,7 [0,6;0,9] to 0,1 [0,0;0,9]. The proportion of clinical cases with no RJA/WI without reason varied from 0 (when excluding neglect) to &gt; 85% (with broadest definition); all corresponded to a possible isolated neglect.

Conclusions

The performances of the algorithm varied tremendously according to the clinical definition level of child maltreatment. Neglect is obviously difficult to clinically detect. Training for healthcare professionals and qualitative studies on obstacles to RJA/WI should be added to this work.

Key messages

The performances of an algorithm to detect non-accidental pediatric burns (maltreatment) using the French hospital discharge database dropped when including neglect, difficult to diagnose clinically. Training for healthcare professionals and qualitative studies on obstacles to the judicial authority (RJA) or worrying information (WI) should be added to this diagnostic study.

FKBP4 connects mTORC2 and PI3K to activate the PDK1/Akt-dependent cell proliferation signaling in breast cancer

Purpose: Among the FKBP family members, FKBP4 has been described to have a potential role in tumorigenesis, and as a putative tissue marker. We previously showed that FKBP4, an HSP90-associated co-chaperone, can elicit immune response as a tumor-specific antigen, and are overexpressed in breast cancer. Experimental design: In this study, we examined how loss of FKBP4 affect breast cancer progression and exploited protein interactomics to gain mechanistic insight into this process. Results: We found that FKBP4 expression is associated with breast cancer progression and prognosis, especially of ER-negative breast cancer. Furthermore, FKBP4 depletion specifically reduces cell growth and proliferation of triple negative breast cancer cell model and xenograft tumor model. Using specific protein interactome strategy by BirA proximity-dependent biotin identification, we demonstrated that FKBP4 is a novel PI3K-Akt-mTOR proximal interacting protein. Conclusion: Our results suggest that FKBP4 interacts with PI3K and can enhance Akt activation through PDK1 and mTORC2.

Abstract 4529: Mapping the protein interactome of mitochondrial intermembrane space proteases identifies a novel function for HTRA2

Mitochondria possess unique proteases that localize to specific sub-compartments of the organelle. However, the functions of these proteases are largely ill-defined. Here, we used proximity-dependent biotinylation (BioID) to map the interactomes of seven proteases located in the intermembrane space of the mitochondria. The mitochondrial intermembrane space proteases HTRA2, OMA1, YME1L1, LACTB, IMMP1L, IMMP2L and PARL were cloned in-frame with the abortive E. coli biotin ligase BirA*, and expressed in 293 T-REx cells. Cell culture media was spiked with biotin for 24 hrs, the cells lysed, and biotinylated proteins were isolated and identified by mass spectrometry. In total, we identified 342 different proteins as high confidence interactors of the seven mitochondrial proteases. Of these, 272 are assigned a GO mitochondrial annotation, and 230 proteins interacted with only 1 or 2 proteases in our dataset. Validation efforts were focused on high temperature requirement peptidase A 2 (HTRA2). HTRA2 is a serine protease that is released into the cytoplasm during apoptosis where it binds Inhibitor of Apoptosis Proteins (IAPs). However, little is known about the function of HTRA2 in the mitochondria. HTRA2 interacted with 60 mitochondrial, 11 nuclear and 4 cytoplasmic proteins, including its known interactor XIAP, and consistent with its known localization to these cellular compartments. HTRA2 interacted with 8 out of 13 components of the MIB complex, a multiprotein assembly that is essential for proper mitochondrial cristae formation. Knockdown of HTRA2 with shRNA in 293T-REx cells disrupted cristae formation and this phenotype was rescued by expression of an shRNA-resistant HTRA2 cDNA. Compared to normal hematopoietic cells, HTRA2 mRNA expression levels are increased in a subgroup of primary AML cells. HTRA2 knockdown in OCI-AML2 leukemia cells led to a similar disruption of mitochondrial cristae. Knockdown of HTRA2 in OCI-AML2 cells led to increased levels of the MIB subunit IMMT, but not two other MIB complex subunits, SAMM50 and CHCHD3. Finally, in cell-free assays, we demonstrate that recombinant HTRA2 can degrade recombinant IMMT, but not SAMM50 or CHCHD3.Thus, we have mapped the interactomes of the proteases of the mitochondrial intermembrane space. Through this effort, we discovered that HTRA2 regulates protein levels of the MIB complex subunit IMMT and that disruption of this process affects mitochondrial cristae formation.

Citation Format: Aaron D. Botham, Etienne Coyaud, Sanjit Nirmalanandhan, Marcela Gronda, Rose Hurren, Neil Maclean, Jonathan St. Germain, Sara Mirali, Estelle Laurent, Brian Raught, Aaron Schimmer. Mapping the protein interactome of mitochondrial intermembrane space proteases identifies a novel function for HTRA2 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4529.

Multidisciplinary team meeting for complex bone and joint infections diagnosis: The PHICTOS study

BACKGROUND

In France, the most severe bone and joint infections (BJI), called "complex" (CBJI), are assessed in a multidisciplinary team meeting (MTM) in a reference center. However, the definition of CBJI, drawn up by the Health Ministry, is not consensual between physicians. The objective was to estimate the agreement for CBJI classification.

METHODS

Initially, five experts from one MTM classified twice, one-month apart, 24 cases as non-BJI, simple BJI or CBJI, using the complete medical record. Secondly, six MTMs classified the same cases using standardized information. Agreements were estimated using Fleiss and Cohen kappa (κ) coefficients.

RESULTS

Inter-expert agreement during one MTM was moderate (κ=0.49), and fair (κ=0.23) when the four non-BJIs were excluded. Intra-expert agreement was moderate (κ=0.50, range 0.27-0.90), not improved with experience. The overall inter-MTM agreement was moderate (κ=0.58), it was better between MTMs with professor (κ=0.65) than without (κ=0.51) and with longer median time per case (κ=0.60) than shorter (κ=0.47). When the four non-BJIs were excluded, the overall agreement decreased (κ=0.40).

CONCLUSION

The first step confirmed the heterogeneity of CBJI classification between experts. The seemingly better inter-MTM than inter-expert agreement could be an argument in favour of MTMs, which are moreover a privileged place to enhance expertise. Further studies are needed to assess these results as well as the quality of care and medico-economic outcomes after a MTM.

Habitat choice meets thermal specialization: Competition with specialists may drive suboptimal habitat preferences in generalists

Limited dispersal is classically considered as a prerequisite for ecological specialization to evolve, such that generalists are expected to show greater dispersal propensity compared with specialists. However, when individuals choose habitats that maximize their performance instead of dispersing randomly, theory predicts dispersal with habitat choice to evolve in specialists, while generalists should disperse more randomly. We tested whether habitat choice is associated with thermal niche specialization using microcosms of the ciliate Tetrahymena thermophila, a species that performs active dispersal. We found that thermal specialists preferred optimal habitats as predicted by theory, a link that should make specialists more likely to track suitable conditions under environmental changes than expected under the random dispersal assumption. Surprisingly, generalists also performed habitat choice but with a preference for suboptimal habitats. Since this result challenges current theory, we developed a metapopulation model to understand under which circumstances such a preference for suboptimal habitats should evolve. We showed that competition between generalists and specialists may favor a preference for niche margins in generalists under environmental variability. Our results demonstrate that the behavioral dimension of dispersal-here, habitat choice-fundamentally alters our predictions of how dispersal evolve with niche specialization, making dispersal behaviors crucial for ecological forecasting facing environmental changes.

PPP1R35 is a novel centrosomal protein that regulates centriole length in concert with the microcephaly protein RTTN

Centrosome structure, function, and number are finely regulated at the cellular level to ensure normal mammalian development. Here, we characterize PPP1R35 as a novel bona fide centrosomal protein and demonstrate that it is critical for centriole elongation. Using quantitative super-resolution microscopy mapping and live-cell imaging we show that PPP1R35 is a resident centrosomal protein located in the proximal lumen above the cartwheel, a region of the centriole that has eluded detailed characterization. Loss of PPP1R35 function results in decreased centrosome number and shortened centrioles that lack centriolar distal and microtubule wall associated proteins required for centriole elongation. We further demonstrate that PPP1R35 acts downstream of, and forms a complex with, RTTN, a microcephaly protein required for distal centriole elongation. Altogether, our study identifies a novel step in the centriole elongation pathway centered on PPP1R35 and elucidates downstream partners of the microcephaly protein RTTN.

National epidemiological study reveals longer paediatric bone and joint infection stays for infants and in general hospitals

AIM

Published studies have suggested that two to five days of intravenous treatment could effectively treat paediatric bone and joint infections (PBJI), allowing a faster discharge. This study analysed the factors associated with PBJI hospital stays lasting longer than five days using the French National Hospital Discharge Database.

METHODS

We selected children under 15 years hospitalised in 2013 with haematogenous PBJIs using a validated French algorithm based on specific diagnosis and surgical procedure codes. Risk factors for stays of more than five days were analysed using logistic regression.

RESULTS

In 2013, 2717 children were hospitalised for PBJI, with 49% staying more than five days. The overall incidence of 22 per 100 000, was highest in males and toddlers. The main causes were septic arthritis (50%) and osteomyelitis (46%) and 50% of the pathogens were Staphylococci. The odd ratios for stays of five days or more were infancy, coded bacteria and sickle cell disease (7.0), having spondylodiscitis rather than septic arthritis (2.2) and being hospitalised in a general hospital rather than a teaching hospital (1.6).

CONCLUSION

Half of the hospital stays exceeded five days, despite scientific evidence supporting a shorter intravenous antibiotherapy regimen. Greater knowledge and widespread use of short treatment regimens are needed.

Key features of bone and joint infections following the implementation of reference centers in France

OBJECTIVES

French reference centers for bone and joint infections (BJI) were implemented from 2009 onwards to improve the management of complex BJIs. This study compared BJI burden before and after the implementation of these reference centers.

PATIENTS AND METHODS

BJI hospital stays were selected from the 2008 and 2013 national hospital discharge database using a validated algorithm, adding the new complex BJI code created in 2011. Epidemiology and economic burden were assessed.

RESULTS

BJI prevalence increased in 2013 (70 vs. 54/100,000 in 2008). Characteristics of BJI remained similar between 2008 and 2013: septic arthritis (50%), increasing prevalence with age and sex, case fatality 5%, mean length of stay 17.5 days, rehospitalization 20%. However, device-associated BJIs increased (34 vs. 26%) as well as costs (€421 million vs. €259 in 2008). Similar device-associated BJI characteristics between 2008 and 2013 were: septic arthritis (70%), case fatality (3%), but with more hospitalizations in reference centers (34 vs. 30%) and a higher cost per stay. Among the 7% of coded complex BJIs, the mean length of stay was 22.2 days and mean cost was €11,960.

CONCLUSIONS

BJI prevalence highly increased in France. Complex BJI prevalence assessment is complicated by the absence of clinical consensus and probable undercoding. A validation of clinical case definition of complex BJI is required.

Conservation of hoverflies (Diptera, Syrphidae) requires complementary resources at the landscape and local scales

Accumulating evidence shows that landscape fragmentation drives the observed worldwide decline in populations of pollinators, particularly in species of Lepidoptera and Hymenoptera. However, Little is known about the effects of landscape fragmentation on hoverfly (Diptera, Syrphidae) communities. Hoverflies provide varied ecosystem services: larvae contribute to waste decomposition (saprophagous species) and pest control (aphidophagous species), and adults pollinate a wide range of flowers.To determine how the diversity and quantity of resources for larvae and adults affect hoverfly abundance and species richness at three spatial scales, we recorded insect visitors of five target plant species in Belgian heathlands, habitats that have decreased considerably due to human activities.Hoverflies represented the most abundant visitors on two plant species, and the second most abundant visitors (after bumblebees) on the other target plant species. A large proportion of hoverflies observed were aphidophagous species associated with coniferous and deciduous forests. Resources for the larvae and floral resources for the adults influenced interactions among hoverflies and plants, but acted at different scales: larval habitat availability (distance to larval habitat) was relevant at the landscape scale, whereas adult resource availability (floral density) was relevant at the plot scale.Hoverfly abundance and species richness decreased with distance to larval habitat but increased with floral density. Moreover, landscape structure and composition had different effects according to hoverfly ecological traits. Landscape composition influenced aphidophagous but not saprophagous hoverflies, in that their abundance and species richness decreased with distance to forests. Maintenance of the interactions between plants and their hoverfly visitors requires complementary resources at both landscape and local scales.