Inibizione selettiva del gene MYCN mediante PNA (acidi peptido nucleici) anti-gene nel rabdomiosarcoma umano

MYCN oncogene amplification/expression is a feature of many childhood tumors, and some adult tumors, and it is associated with poor prognosis. While MYC expression is ubiquitary, MYCN has a restricted expression after birth and it is an ideal target for an effective therapy. PNAs belong to the latest class of nucleic acid-based therapeutics, and they can bind chromosomal DNA and block gene transcription (anti-gene activity). We have developed an anti-gene PNA that targets specifically the MYCN gene to block its transcription. We report for the first time MYCN targeted inhibition in Rhabdomyosarcoma (RMS) by the anti-MYCN-PNA in RMS cell lines (four ARMS and four ERMS) and in a xenograft RMS mouse model. Rhabdomyosarcoma is the most common pediatric soft-tissue sarcoma, comprising two main subgroups [Alveolar (ARMS) and Embryonal (ERMS)]. ARMS is associated with a poorer prognosis. MYCN amplification is a feature of both the ERMS and ARMS, but the MYCN amplification and expression levels shows a significant correlation and are greater in ARMS, in which they are associated with adverse outcome. We found that MYCN mRNA and protein levels were higher in the four ARMS (RH30, RH4, RH28 and RMZ-RC2) than in the four ERMS (RH36, SMS-CTR, CCA and RD) cell lines. The potent inhibition of MYCN transcription was highly specific, it did not affect the MYC expression, it was followed by cell-growth inhibition in the RMS cell lines which correlated with the MYCN expression rate, and it led to complete cell-growth inhibition in ARMS cells. We used a mutated- PNA as control. MYCN silencing induced apoptosis. Global gene expression analysis (Affymetrix microarrays) in ARMS cells treated with the anti-MYCN-PNA revealed genes specifically induced or repressed, with both genes previously described as targets of N-myc or Myc, and new genes undescribed as targets of N-myc or Myc (mainly involved in cell cycle, apoptosis, cell motility, metastasis, angiogenesis and muscle development). The changes in the expression of the most relevant genes were confirmed by Real-Time PCR and western blot, and their expression after the MYCN silencing was evaluated in the other RMS cell lines. The in vivo study, using an ARMS xenograft murine model evaluated by micro-PET, showed a complete elimination of the metabolic tumor signal in most of the cases (70%) after anti-MYCN-PNA treatment (without toxicity), whereas treatment with the mutated-PNA had no effect. Our results strongly support the development of MYCN anti-gene therapy for the treatment of RMS, particularly for poor prognosis ARMS, and of other MYCN-expressing tumors.

New approaches to open problems in gene expression microarray data

In the past decade, the advent of efficient genome sequencing tools and high-throughput experimental biotechnology has lead to enormous progress in the life science. Among the most important innovations is the microarray tecnology. It allows to quantify the expression for thousands of genes simultaneously by measurin the hybridization from a tissue of interest to probes on a small glass or plastic slide. The characteristics of these data include a fair amount of random noise, a predictor dimension in the thousand, and a sample noise in the dozens. One of the most exciting areas to which microarray technology has been applied is the challenge of deciphering complex disease such as cancer. In these studies, samples are taken from two or more groups of individuals with heterogeneous phenotypes, pathologies, or clinical outcomes. these samples are hybridized to microarrays in an effort to find a small number of genes which are strongly correlated with the group of individuals. Eventhough today methods to analyse the data are welle developed and close to reach a standard organization (through the effort of preposed International project like Microarray Gene Expression Data -MGED- Society [1]) it is not unfrequant to stumble in a clinician's question that do not have a compelling statistical method that could permit to answer it.The contribution of this dissertation in deciphering disease regards the development of new approaches aiming at handle open problems posed by clinicians in handle specific experimental designs. In Chapter 1 starting from a biological necessary introduction, we revise the microarray tecnologies and all the important steps that involve an experiment from the production of the array, to the quality controls ending with preprocessing steps that will be used into the data analysis in the rest of the dissertation. While in Chapter 2 a critical review of standard analysis methods are provided stressing most of problems that In Chapter 3 is introduced a method to adress the issue of unbalanced design of miacroarray experiments. In microarray experiments, experimental design is a crucial starting-point for obtaining reasonable results. In a two-class problem, an equal or similar number of samples it should be collected between the two classes. However in some cases, e.g. rare pathologies, the approach to be taken is less evident. We propose to address this issue by applying a modified version of SAM [2]. MultiSAM consists in a reiterated application of a SAM analysis, comparing the less populated class (LPC) with 1,000 random samplings of the same size from the more populated class (MPC) A list of the differentially expressed genes is generated for each SAM application. After 1,000 reiterations, each single probe given a "score" ranging from 0 to 1,000 based on its recurrence in the 1,000 lists as differentially expressed. The performance of MultiSAM was compared to the performance of SAM and LIMMA [3] over two simulated data sets via beta and exponential distribution. The results of all three algorithms over low- noise data sets seems acceptable However, on a real unbalanced two-channel data set reagardin Chronic Lymphocitic Leukemia, LIMMA finds no significant probe, SAM finds 23 significantly changed probes but cannot separate the two classes, while MultiSAM finds 122 probes with score >300 and separates the data into two clusters by hierarchical clustering. We also report extra-assay validation in terms of differentially expressed genes Although standard algorithms perform well over low-noise simulated data sets, multi-SAM seems to be the only one able to reveal subtle differences in gene expression profiles on real unbalanced data. In Chapter 4 a method to adress similarities evaluation in a three-class prblem by means of Relevance Vector Machine [4] is described. In fact, looking at microarray data in a prognostic and diagnostic clinical framework, not only differences could have a crucial role. In some cases similarities can give useful and, sometimes even more, important information. The goal, given three classes, could be to establish, with a certain level of confidence, if the third one is similar to the first or the second one. In this work we show that Relevance Vector Machine (RVM) [2] could be a possible solutions to the limitation of standard supervised classification. In fact, RVM offers many advantages compared, for example, with his well-known precursor (Support Vector Machine - SVM [3]). Among these advantages, the estimate of posterior probability of class membership represents a key feature to address the similarity issue. This is a highly important, but often overlooked, option of any practical pattern recognition system. We focused on Tumor-Grade-three-class problem, so we have 67 samples of grade I (G1), 54 samples of grade 3 (G3) and 100 samples of grade 2 (G2). The goal is to find a model able to separate G1 from G3, then evaluate the third class G2 as test-set to obtain the probability for samples of G2 to be member of class G1 or class G3. The analysis showed that breast cancer samples of grade II have a molecular profile more similar to breast cancer samples of grade I. Looking at the literature this result have been guessed, but no measure of significance was gived before.

Mechanisms of cell senescence: p21 and DNA damage response in aging and longevity

Theory of aging postulates that aging is a remodeling process where the body of survivors progressively adapts to internal and external damaging agents they are exposed to during several decades. Thus , stress response and adaptation mechanisms play a fundamental role in the aging process where the capability of adaptating effects, certainly, also is related the lifespan of each individual. A key gene linking aging to stress response is indeed p21, an induction of cyclin-dependent kinase inhibitor which triggers cell growth arrest associated with senescence and damage response and notably is involved in the up-regulation of multiple genes that have been associated with senescence or implicated in age-related . This PhD thesis project that has been performed in collaboration with the Roninson Lab at Ordway Research Institute in Albany, NY had two main aims: -the testing the hypothesis that p21 polymorphisms are involved in longevity -Evaluating age-associated differences in gene expression and transcriptional response to p21 and DNA damage In the first project, trough PCR-sequencing and Sequenom strategies, we we found out that there are about 30 polymorphic variants in the p21 gene. In addition, we found an haplotpype located in -5kb region of the p21 promoter whose frequency is ~ 2 fold higher in centenarians than in the general population (Large-scale analysis of haplotype frequencies is currently in progress). Functional studies I carried out on the promoter highilighted that the ―centenarian‖ haplotype doesn’t affect the basal p21 promoter activity or its response to p53. However, there are many other possible physiological conditions in which the centenarian allele of the p21 promoter may potentially show a different response (IL6, IFN,progesterone, vitamin E, Vitamin D etc). In the second part, project #2, trough Microarrays we seeked to evaluate the differences in gene expression between centenarians, elderly, young in dermal fibroblast cultures and their response to p21 and DNA damage. Microarray analysis of gene expression in dermal fibroblast cultures of individuals of different ages yielded a tentative "centenarian signature". A subset of genes that were up- or downregulated in centenarians showed the same response to ectopic expression of p21, yielding a putative "p21-centenarian" signature. Trough RQ-PCR (as well Microarrays studies whose analysis is in progress) we tested the DNA damage response of the p21-centenarian signature genes showing a correlation stress/aging in additional sets of young and old samples treated with p21-inducing drug doxorubicin thus finding for a subset of of them , a response to stress age-related.

Studio del pathway della Displasia Ectodermica Anidrotica (EDA)

Anhidrotic Ectodermal Dysplasia (EDA), is the most frequent form among Ectodermal Dysplasias, hereditary genetic disorders causing ectodermal appendages defective development. Indeed, EDA is characterized by defective formation of hair follicles, sweat glands and teeth both in human patients and animals. EDA, the gene mutated in Anhidrotic Ectodermal Dysplasia, encodes Ectodysplasin, a TNF family member that activates NF-kB mediated transcription. This disease can occur with mutations in other EDA-NF-kB pathway members, as EDA receptor, EDAR and its adapter, EDARADD. Moreover, mutations in TRAF6, NEMO, IKB and NF-kBs genes are responsible for Immunodeficiency associated EDA (EDA-ID). Several molecules, as SHH, WNT/DKK, BMP and LTβ, have already been reported to be EDA pathway regulators or effectors although the knowledge of the full spectrum of EDA targets remains incomplete. During the first part of the research project a gene expression analysis was performed in primary keratinocytes from Wild-type and Tabby (EDA model mouse) mice to identify novel EDA target genes. Earlier expression profiling at various developmental time points in Tabby and Wild-type mouse skin reported genes differentially expressed in the two samples and, to increase the resolution to find genes whose expression may be restricted to epidermal cells, the study was extended to primary keratinocyte cultures established from E19 Wild-type and Tabby skin. Using microarrays bearing 44,000 gene probes, we found 385 “preliminary candidate” genes whose expression was significantly affected by Eda defect. By comparing expression profiles to those from Eda-A1 (where Eda-A1 is highly expressed) transgenic skin, we restricted the list to 38 “candidate EDA targets”, 14 of which were already known to be expressed in hair follicles or epidermis. This work confirmed expression changes for 3 selected genes, Tbx1, Bmp7, and Jag1, both in primary keratinocytes and in Wild-type and Tabby whole skin, by Q-PCR and Western blotting analyses. Thus, this study detected novel candidate pathways downstream of EDA. In the second part of the research project, plasmid constructs were produced and analyzed to create a transgenic mouse model for Immunodeficiency associated EDA disease (XL-EDA-ID). In particular, plasmids containing mouse Wild-type and mutated Nemo cDNA under K-17 epidermis-specific promoter control and a Flag tag, were prepared, on the way to confine transgene expression to mice epidermis and to determine EDA phenotype without immunodeficiency for a comparison to Tabby model phenotype. EDA-ID mutations reported in patients and selected for this study are: C417R (C409R in mouse), causing Zinc Finger protein domain destabilization and A288G (A282G in mouse) affecting oligomerization of the protein. Moreover, the ex-novo mutation, ZnF, C-terminal Zinc Finger domain deletion, was tested. Thus, the constructs were analyzed by transient transfection, Western blotting and luciferase assays techniques, detecting Nemo Wild-type and mutant protein products and residue NF-kB activity in presence of mutants, after TNF stimulation. In particular, MEF_Nemo-/- cell line was used to monitor NF-kB activity without endogenous Nemo gene. Results show reduced NF-kB activity in presence of mutated Nemo forms compared to Wild-type: 81% for A282G (A288G in human); 24% for C409R (C417R in human); 15% for ZnF. C409R mutation (C417R in human), reported in 6 EDA-ID human patients, was selected to prepare transgenic model mouse. Mice (white, FVP) born following K17-promoter-Flag-Nemo_C409R plasmid region pronuclear injection, were analyzed for the transgene presence in the genotype and a preliminar examination of their phenotype was performed. In particular, one mouse showed considerable coat defects if compared to Wild-type mice. This preliminar analysis suggests a possible influence of Nemo mutant over-expression in epidermis without immunodeficiency. Still, more microscopic studies to analyze hair subtypes, Guard, Awl and Zigzag (usually alterated inTabby mouse model), Immunohistochemistry experiments to detect epidermis restricted Nemo expression and sweat glands analysis, will follow. This and other transgene positive mice will be crossed with black mice C57BL6 to obtain at least two indipendent agouti lines to analyze. Theses mice will be used in EDA target genes detection through microarrays. Following, plasmid constructs containing other Nemo mutant forms (A282G and ZnF) might be studied by the same experimental approaches to prepare more transgenic model mice to compare to Nemo_C409R and Tabby mouse models.

Identification of surface protein complexes of Streptococcus pyogenes through protein microarray technology

A systematic characterization of the composition and structure of the bacterial cell-surface proteome and its complexes can provide an invaluable tool for its comprehensive understanding. The knowledge of protein complexes composition and structure could offer new, more effective targets for a more specific and consequently effective immune response against a complex instead of a single protein. Large-scale protein-protein interaction screens are the first step towards the identification of complexes and their attribution to specific pathways. Currently, several methods exist for identifying protein interactions and protein microarrays provide the most appealing alternative to existing techniques for a high throughput screening of protein-protein interactions in vitro under reasonably straightforward conditions. In this study approximately 100 proteins of Group A Streptococcus (GAS) predicted to be secreted or surface exposed by genomic and proteomic approaches were purified in a His-tagged form and used to generate protein microarrays on nitrocellulose-coated slides. To identify protein-protein interactions each purified protein was then labeled with biotin, hybridized to the microarray and interactions were detected with Cy3-labelled streptavidin. Only reciprocal interactions, i. e. binding of the same two interactors irrespective of which of the two partners is in solid-phase or in solution, were taken as bona fide protein-protein interactions. Using this approach, we have identified 20 interactors of one of the potent toxins secreted by GAS and known as superantigens. Several of these interactors belong to the molecular chaperone or protein folding catalyst families and presumably are involved in the secretion and folding of the superantigen. In addition, a very interesting interaction was found between the superantigen and the substrate binding subunit of a well characterized ABC transporter. This finding opens a new perspective on the current understanding of how superantigens are modified by the bacterial cell in order to become major players in causing disease.

Studio di marcatori biologici prognostici nel linfoma di Hodgkin

Recent reports showed that early-interim PET-scan is the only tool predicting treatment outcome in advanced-stage classical Hodgkin lymphoma (asCHL). We evaluated the prognostic impact of a series of immunohistochemical markers, mentioned in literature as prognostic factors, on tissue microarrays assembled from biopsies of 220 patients: STAT1, SAP, TOP2A, PCNA and CD20, both in neoplastic (HRSC) and microenvironment cells (MC); RRM2, MAD2, CDC2, BCL2, P53, BCL11A and EBER in HRSC; ALDH1A1, TIA-1, granzyme B, perforin, FOXP3, and PD-1 in MC. All patients had been treated with standard ABVD ± Rx therapy. Interim-PET after 2 ABVD courses was evaluated according to the criteria indicated by Gallamini in his study (Journal of Clinical Oncology, 2007). The survival analysis has been performed in a subset of 138 patients whose complete clinical information were available: the mean age was 33.3 years (14-79), the stage III-IVB in 98 and IIB in 40, and the mean follow-up 38.1 months (7.6-71.9). Histopathology review showed: NS-I 75, NS-II 22, MC 20, DL 3, and CHL/nos 18 cases. Interim-PET was positive in 30 patients, while treatment failure was recorded in 32. In univariate analysis the factors related to treatment outcome were BCL2 on HRSC (cut-off value 50%), STAT1/SAP on MC, and PET (Log-rank 6.9, 7.9 and 93.9 respectively). The combined expression of STAT1 and SAP was scored in three levels depending on the architectural pattern: score 0 for expression of both with a diffuse/rosetting pattern; score 1 for discordant combination of diffuse/rosetting and scattered patterns; score 2 for both markers with a scattered pattern; the 3y-PFS were 87.4%, 69.9% and 61.9% respectively. In multivariate analysis PET, BCL2 and STAT1/SAP remained significant (HR: 24.8, 4.6, 7.5 and 5.6, respectively; p<.01). The proposed model is able to predict treatment response in AsCHL, even if with a lower efficacy than PET. However, unlike PET, it can be applied upfront therapy.

Studio di marcatori immunoistochimici, analisi FISH e ruolo dei microRNA nelle neoplasie gliali di basso e di alto grado

Gliomas are the most common primary brain tumours. Despite advances in surgical techniques, postoperative supportive care, radiation and adjuvant systemic therapy, the life expectancy of patients with high grade glioma has remained essentially poor. Furthermore differential diagnosis among astrocytomas, oligodendrogliomas and oligoastrocytomas is very challenging and subject to inter-observer variability. The purpose of the research was: 1) to investigate a series of high grade and low grade gliomas at gene and protein (immunohistochemistry) levels to disclose possible genetic portraits of malignancy; 2) to verify the utility of Nogo-A, Olig-2 and synaptophysin in providing a correct histological diagnosis of oligodendroglioma and to investigate a possible complementary role in selecting the best areas suitable for detecting 1p/19q codeletion using FISH analysis; 3) to study the role of microRNA in high grade gliomas. In order to obtain these goals large series of brain tumors were studied with DNA microarrays, immunohistochemistry and RT-PCR The results demonstrated that: - Overexpression of IGFBP-2 and CDC20 is highly related to glioblastomas and their immunopositivity can be useful for the identification of glioblastoma in small biopsies. - Nogo-A is the most useful and specific marker in differentiating oigodendrogliomas from other gliomas. Furthermore, using a Nogo-A driven FISH analysis, it is possible to identify a larger number of 1p19q codeletions in gliomas. - microRNAs can be studied in paraffin embedded tissues better than in fresh tissues. A series of six microRNA, significatively deregulated in glioblastomas, may represent a genetic signature with prognostic and predictive value and could constitute candidates for novel anti-cancer therapeutics.

Structural and functional analysis of centromeric chromatin

Animal neocentromeres are defined as ectopic centromeres that have formed in non-centromeric locations and avoid some of the features, like the DNA satellite sequence, that normally characterize canonical centromeres. Despite this, they are stable functional centromeres inherited through generations. The only existence of neocentromeres provide convincing evidence that centromere specification is determined by epigenetic rather than sequence-specific mechanisms. For all this reasons, we used them as simplified models to investigate the molecular mechanisms that underlay the formation and the maintenance of functional centromeres. We collected human cell lines carrying neocentromeres in different positions. To investigate the region involved in the process at the DNA sequence level we applied a recent technology that integrates Chromatin Immuno-Precipitation and DNA microarrays (ChIP-on-chip) using rabbit polyclonal antibodies directed against CENP-A or CENP-C human centromeric proteins. These DNA binding-proteins are required for kinetochore function and are exclusively targeted to functional centromeres. Thus, the immunoprecipitation of DNA bound by these proteins allows the isolation of centromeric sequences, including those of the neocentromeres. Neocentromeres arise even in protein-coding genes region. We further analyzed if the increased scaffold attachment sites and the corresponding tighter chromatin of the region involved in the neocentromerization process still were permissive or not to transcription of within encoded genes. Centromere repositioning is a phenomenon in which a neocentromere arisen without altering the gene order, followed by the inactivation of the canonical centromere, becomes fixed in population. It is a process of chromosome rearrangement fundamental in evolution, at the bases of speciation. The repeat-free region where the neocentromere initially forms, progressively acquires extended arrays of satellite tandem repeats that may contribute to its functional stability. In this view our attention focalized to the repositioned horse ECA11 centromere. ChIP-on-chip analysis was used to define the region involved and SNPs studies, mapping within the region involved into neocentromerization, were carried on. We have been able to describe the structural polymorphism of the chromosome 11 centromeric domain of Caballus population. That polymorphism was seen even between homologues chromosome of the same cells. That discovery was the first described ever. Genomic plasticity had a fundamental role in evolution. Centromeres are not static packaged region of genomes. The key question that fascinates biologists is to understand how that centromere plasticity could be combined to the stability and maintenance of centromeric function. Starting from the epigenetic point of view that underlies centromere formation, we decided to analyze the RNA content of centromeric chromatin. RNA, as well as secondary chemically modifications that involve both histones and DNA, represents a good candidate to guide somehow the centromere formation and maintenance. Many observations suggest that transcription of centromeric DNA or of other non-coding RNAs could affect centromere formation. To date has been no thorough investigation addressing the identity of the chromatin-associated RNAs (CARs) on a global scale. This prompted us to develop techniques to identify CARs in a genome-wide approach using high-throughput genomic platforms. The future goal of this study will be to focalize the attention on what strictly happens specifically inside centromere chromatin.

Farmacogenomica della Clofarabina nel trattamento delle Leucemie Acute pediatriche: identificazione di nuovi bersagli molecolari e del profilo genomico associato all’efficacia terapeutica del farmaco antitumorale

In quest’ultimi decenni si è assistito ad un notevole miglioramento nella terapia delle Leucemie Acute (LA) pediatriche, nonostante tutto si assiste oggi ad una fase di plateau della curva di sopravvivenza e le leucemie continuano a costituire la principale causa di morte pediatrica per malattia. Ulteriori progressi nel trattamento delle LA potrebbero essere ottenuti mediante studi di farmacogenomica che, identificando le componenti genetiche associate alla risposta individuale ai trattamenti farmacologici, consentono il disegno di terapie personalizzate e tumore-specifiche, ad alta efficacia e bassa tossicità per ciascun paziente. Il lavoro svolto è stato, dunque, finalizzato allo studio della farmacogenomica del farmaco antitumorale Clofarabina (CLO) nel trattamento delle LA pediatriche al fine di identificare marcatori genetici predittivi di risposta delle cellule leucemiche al farmaco, delucidare i meccanismi di resistenza cellulare ed individuare nuovi bersagli verso cui indirizzare terapie più mirate ed efficaci. L’analisi in vitro della sensibilità alla CLO di blasti provenienti da pazienti pediatrici affetti da Leucemia Acuta Linfoblastica (LAL) e Mieloide (LAM) ha consentito l’identificazione di due sottopopolazioni di cellule LAL ad immunofenotipo T a diversa sensibilità alla CLO. Mediante DNA-microarrays, si è identificata la “signature” genetica specificamente associata alla diversa risposta delle cellule LAL-T al farmaco. Successivamente, la caratterizzazione funzionale dei geni differenziali e l’analisi dei pathways hanno consentito l’identificazione specifica di potenziali biomarcatori di risposta terapeutica aprendo nuove prospettive per la comprensione dei meccanismi di resistenza cellulare alla CLO e suggerendo un nuovo bersaglio terapeutico per le forme LAL-T a bassa sensibilità al farmaco. In conclusione, nel lavoro svolto si sono identificati set di geni e pathways di rilievo biologico per la risposta delle cellule LAL-T alla CLO suggerendo marcatori genetici in grado di identificare i soggetti eleggibili per il trattamento o verso cui disegnare terapie innovative. Il lavoro è paradigma per l’applicazione della farmacogenomica in altre neoplasie.

adaptive capabilities of the pi3k/akt/mtor pathway in acute myeloid leukemia revealed by the use of selective inhibitors

Because of its aberrant activation, the PI3K/AKT/mTOR signaling pathway represents a pharmacological target in blast cells from patients with acute myelogenous leukemia (AML). Using Reverse Phase Protein Microarrays (RPMA), we have analyzed 20 phosphorylated epitopes of the PI3K/Akt/mTor signal pathway of peripheral blood and bone marrow specimens of 84 patients with newly diagnosed AML. Fresh blast cells were grown for 2 h, 4 h or 20 h untreated or treated with a panel of phase I or phase II Akt allosteric inhibitors, either alone or in combination with the mTOR kinase inhibitor Torin1 or the broad RTK inhibitor Sunitinib. By unsupervised hierarchical clustering a strong phosphorylation/activity of most of the sampled members of the PI3K/Akt/mTOR pathway was observed in 70% of samples from AML patients. Remarkably, however, we observed that inhibition of Akt phosphorylation, as well as of its substrates, was transient, and recovered or even increased far above basal level after 20 h in 60% samples. We demonstrated that inhibition of Akt induces FOXO-dependent insulin receptor expression and IRS-1 activation, attenuating the effect of drug treatment by reactivation of PI3K/Akt. Consistent with this model we found that combined inhibition of Akt and RTKs is much more effective than either alone, revealing the adaptive capabilities of signaling networks in blast cells and highliting the limations of these drugs if used as monotherapy.

Dissection of the protective response elicited by the DOMV component of the 4CMenB vaccine

Neisseria meningitidis serogroup B is the major etiological agent of meningitis and life-threatening sepsis, against which two vaccines are licensed. The 4CMenB vaccine is composed of three major protein antigens (fHbp, NHBA and NadA) and detergent-extracted outer membrane vesicles (DOMV) from the NZ98/254 strain. DOMV are safe, immunogenic and able to raise bactericidal antibodies, mainly attributed to the immunodominant PorA protein. Nevertheless, DOMV offer a complex reservoir of potentially immunogenic proteins, whose relative contribution in protection is still poorly characterized. By testing antisera from vaccinated infants in serum bactericidal assay, we observed that the addition of DOMV in the vaccine formulation enhanced breadth of coverage compared to recombinant proteins alone against a panel of 11 meningococcal strains mismatched for the vaccine antigens. To unravel the DOMV components involved in such protection, 30 DOMV antigens were cloned and expressed in Escherichia coli as recombinant proteins and/or in vesicles to maintain their native conformation. Samples obtained were both included in tailor-made protein-microarrays to immunoprofile the antibody repertoire raised by DOMV-containing formulations and were individually used for mouse immunization studies to assess their ability to induce bactericidal antibodies. The protein-array immunosignature of mouse DOMV/4CMenB antisera unveiled a subset of 8 DOMV-reactive proteins potentially responsible for the additional protective responses. The antisera derived from mouse immunizations showed high levels of antibodies and recognized the corresponding antigen across different meningococcal strains. Among the protein-array reactive antigens, OpcA, NspA and PorB induced antibodies able to kill 10 of the 11 genetically diverse meningococcal strains and the specificity of the protective role of OpcA and PorB was also confirmed in 4CMenB infant vaccinee sera. In conclusion, we identified additional PorA-independent antigens within DOMV involved in broadening the coverage of 4CMenB, thus supporting the key role played by vesicles in this multivalent formulation.