Distinct Repertoires Research Articles

A distinct repertoire of cancer-associated fibroblasts is enriched in cribriform prostate cancer.

Outcomes for men with localized prostate cancer vary widely, with some men effectively managed without treatment on active surveillance, while other men rapidly progress to metastatic disease despite curative‐intent therapies. One of the strongest prognostic indicators of outcome is grade groups based on the Gleason grading system. Gleason grade 4 prostate cancer with cribriform morphology is associated with adverse outcomes and can be utilized clinically to improve risk stratification. The underpinnings of disease aggressiveness associated with cribriform architecture are not fully understood. Most studies have focused on genetic and molecular alterations in cribriform tumor cells; however, less is known about the tumor microenvironment in cribriform prostate cancer. Cancer‐associated fibroblasts (CAFs) are a heterogeneous population of fibroblasts in the tumor microenvironment that impact cancer aggressiveness. The overall goal of this study was to determine if cribriform prostate cancers are associated with a unique repertoire of CAFs. Radical prostatectomy whole‐tissue sections were analyzed for the expression of fibroblast markers (ASPN in combination with FAP, THY1, ENG, NT5E, TNC, and PDGFRβ) in stroma adjacent to benign glands and in Gleason grade 3, Gleason grade 4 cribriform, and Gleason grade 4 noncribriform prostate cancer by RNAscope®. Halo® Software was used to quantify percent positive stromal cells and expression per positive cell. The fibroblast subtypes enriched in prostate cancer were highly heterogeneous. Both overlapping and distinct populations of low abundant fibroblast subtypes in benign prostate stroma were enriched in Gleason grade 4 prostate cancer with cribriform morphology compared to Gleason grade 4 prostate cancer with noncribriform morphology and Gleason grade 3 prostate cancer. In addition, gene expression was distinctly altered in CAF subtypes adjacent to cribriform prostate cancer. Overall, these studies suggest that cribriform prostate cancer has a unique tumor microenvironment that may distinguish it from other Gleason grade 4 morphologies and lower Gleason grades.

A sex-specific switch between visual and olfactory inputs underlies adaptive sex differences in behavior

SummaryAlthough males and females largely share the same genome and nervous system, they differ profoundly in reproductive investments and require distinct behavioral, morphological, and physiological adaptations. How can the nervous system, while bound by both developmental and biophysical constraints, produce these sex differences in behavior? Here, we uncover a novel dimorphism in Drosophila melanogaster that allows deployment of completely different behavioral repertoires in males and females with minimum changes to circuit architecture. Sexual differentiation of only a small number of higher order neurons in the brain leads to a change in connectivity related to the primary reproductive needs of both sexes—courtship pursuit in males and communal oviposition in females. This study explains how an apparently similar brain generates distinct behavioral repertoires in the two sexes and presents a fundamental principle of neural circuit organization that may be extended to other species.

Distinct antibody repertoires against endemic human coronaviruses in children and adults.

Four endemic human coronaviruses (HCoVs) are commonly associated with acute respiratory infection in humans. B cell responses to these “common cold” viruses remain incompletely understood. Here we report a comprehensive analysis of CoV-specific antibody repertoires in 231 children and 1168 adults using phage immunoprecipitation sequencing. Seroprevalence of antibodies against endemic HCoVs ranged between approximately 4% and 27% depending on the species and cohort. We identified at least 136 novel linear B cell epitopes. Antibody repertoires against endemic HCoVs were qualitatively different between children and adults in that anti-HCoV IgG specificities more frequently found among children targeted functionally important and structurally conserved regions of the spike, nucleocapsid, and matrix proteins. Moreover, antibody specificities targeting the highly conserved fusion peptide region and S2′ cleavage site of the spike protein were broadly cross-reactive with peptides of epidemic human and nonhuman coronaviruses. In contrast, an acidic tandem repeat in the N-terminal region of the Nsp3 subdomain of the HCoV-HKU1 polyprotein was the predominant target of antibody responses in adult donors. Our findings shed light on the dominant species-specific and pan-CoV target sites of human antibody responses to coronavirus infection, thereby providing important insights for the development of prophylactic or therapeutic monoclonal antibodies and vaccine design.

Characterization of ascites- and tumor-infiltrating γδ T cells reveals distinct repertoires and a beneficial role in ovarian cancer.

The role of γδ T cells in antitumor immunity has been under investigation for the past two decades, but little is known about their contribution to clinical outcomes in patients. Here, we set out to define the clonotypic, phenotypic, and functional features of γδ T cells in peripheral blood, ascites, and metastatic tumor tissue from patients with advanced epithelial ovarian cancer. T cell receptor (TCR) sequencing of the γ chain revealed that tumor-infiltrating γδ T cells have a unique and skewed repertoire with high TCR diversity and low clonality. In contrast, ascites-derived γδ T cells presented a lower TCR diversity and higher clonality, suggesting a TCR-dependent clonal focusing at this site. Further investigation showed that tumor samples had abundant γδ T cells with a tissue-resident, activation-associated phenotype, less usage of Vγ9 and an impaired response to adaptive-associated stimuli, implying an innate-like activation pathway, rather than an adaptive TCR-engaging pathway, at these tumor sites. Furthermore, high γδ T cell cytokine responsiveness upon stimulation was associated with a favorable outcome for patients in terms of both overall survival and reduced residual tumor burden after primary surgery. Last, the functionality of γδ T cells and patient survival were negatively affected by the proportions of CD39-expressing T cells, highlighting the potential of CD39 as a target to improve γδ T cell responses and unleash their antitumor capabilities.

Effect of fluoxetine on seizures in rats with high susceptibility to audiogenic stress

The seizures, triggered by a loud sound in laboratory animals, are associated with the imbalance of the brain monoamines. Serotonin (5-HT) is regarded as one of the principal neurotransmitters to be involved in regulation of wide variety of physiological and psychological processes. Among the drugs that affect 5-HT synaptic transmission, the leading role is given to selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine. The aim of the study is to investigate the effects of fluoxetine on seizures in Wistar rats with high susceptibility to audiogenic stress. The study was performed on male Wistar rats. Before the experiments, the animals were tested for susceptibility to audiogenic seizures by exposure to a sound of 90-110 dB for 2 min in the soundproof box. The difference between congenital susceptibility to seizures served as a basis for dividing animals into two groups: Seizure-susceptible (SS) and seizure-tolerant (ST) rats. One hour before the experiment, the experimental animals were orally administered with fluoxetine, while the control rats were treated with distilled water. The effect of fluoxetine on the level of the biogenic amines in different regions of the brain was determined by enzyme-linked immunosorbent assay (ELISA). It has been shown that in 100% of the cases, the control SS rats, exposed to audiogenic stimulus, exhibited wild running around in circles and jumping as some of the signs of seizure responses that evolved into tonic-clonic seizures in 70% of the cases. As regards the experimental SS animals: Only in 60% of the cases (P<0.05), they exhibited wild running and flinch, which did not evolve into the tonic-clonic phase. Decreased manifestation of seizures in the experimental SS rats under acute administration of fluoxetine may be explained by highly distinctive repertoire and spatial distribution of 5-HT receptors in their brain structures in comparison to the ST rats. The study of the monoaminergic mechanisms of seizure generation is of practical importance due to the existence of pharmacological agents, which selectively affect the activity of the monoaminergic systems of the brain, as well as the metabolism of the monoamines synthesized by them.

Primed to vocalize: Wild-derived male house mice increase vocalization rate and diversity after a previous encounter with a female.

Males in a wide variety of taxa, including insects, birds and mammals, produce vocalizations to attract females. Male house mice emit ultrasonic vocalizations (USVs), especially during courtship and mating, which are surprising complex. It is often suggested that male mice vocalize at higher rates after interacting with a female, but the evidence is mixed depending upon the strain of mice. We conducted a study with wild-derived house mice (Mus musculus musculus) to test whether male courtship vocalizations (i.e., vocalizations emitted in a sexual context) are influenced by a prior direct interaction with a female, and if so, determine how long the effect lasts. We allowed sexually naïve males to directly interact with a female for five minutes (sexual priming), and then we recorded males’vocalizations either 1, 10, 20, or 30 days later when presented with an unfamiliar female (separated by a perforated partition) and female scent. We automatically detected USVs and processed recordings using the Automatic Mouse Ultrasound Detector (A-MUD version 3.2), and we describe our improved version of this tool and tests of its performance. We measured vocalization rate and spectro-temporal features and we manually classified USVs into 15 types to investigate priming effects on vocal repertoire diversity and composition. After sexual priming, males emitted nearly three times as many USVs, they had a larger repertoire diversity, and their vocalizations had different spectro-temporal features (USV length, slope and variability in USV frequency) compared to unprimed controls. Unprimed control males had the most distinctive repertoire composition compared to the primed groups. Most of the effects were found when comparing unprimed to all primed males (treatment models), irrespective of the time since priming. Timepoint models showed that USV length increased 1 day after priming, that repertoire diversity increased 1 and 20 days after priming, and that the variability of USV frequencies was lower 20 and 30 days after priming. Our results show that wild-derived male mice increased the number and diversity of courtship vocalizations if they previously interacted with a female. Thus, the USVs of house mice are not only context-dependent, they depend upon previous social experience and perhaps the contexts of these experiences. The effect of sexual priming on male courtship vocalizations is likely mediated by neuro-endocrine-mechanisms, which may function to advertise males’ sexual arousal and facilitate social recognition.

The violence of norms: resisting repertoires of gender violence in post-conflict Colombia

ABSTRACT Feminist scholarship on gender violence in Latin America has elucidated its ubiquity and deep entrenchment within many societies, from the colonial encounter until the present day. As such, it remains important to enquire into the relationship between sociocultural norms and gender violence: how norms enable and legitimate gender violence, and how these norms can be reconfigured to resist gender violence. This article draws on Judith Butler’s work on normative violence to explore how norms enabled, legitimated and obscured the distinct repertoires of gender violence in Colombian civilian society and left-wing rebel group the Revolutionary Armed Forces of Colombia (FARC). Butler’s theorization on how norms can be challenged, both through different gender performances and the revision of criteria of gender intelligibility, is then extended to understanding the emergence of resistance to gender violence in The Common Alternative Revolutionary Force, the political party which the FARC transitioned into in 2017.

“Be Less of a Slave to the News”: A Texto-Material Perspective on News Avoidance among Young Adults

ABSTRACT The distinct media repertoire of young adults in the digital age, especially their increasing ability to bypass the news media, inspires a wealth of research. While previous studies have focused on social- and content-related motivations to avoid the news, we have yet to fully understand the interplay of such motivations with material, technology-related considerations. Drawing on 36 in-depth interviews with Israeli young adults, this paper explores the varied motivations of young audiences to avoid the news through a texto-material conceptualization of news avoidance as directed at both contents and objects. An inductive-qualitative analysis of young adults' media consumption narratives identified three main dimensions: content, medium, and user-oriented news avoidance. The study demonstrates the material aspects of both deliberate and unintentional news avoidance, and how they relate to content-oriented considerations. Furthermore, the Israeli socio-political context reveals that in times of crisis, these motivations are shared by both heavy and light news consumers. Taken together, the different avoidance motivations and practices identified in this study provide an analytical framework to further understand news avoidance and design differentiated strategies to address young adults' disengagement from news.

Rethinking enhancement substance use: A critical discourse studies approach

BackgroundWe draw on both interdisciplinary enhancement substance use research and critical drug studies scholarship to reconceptualise enhancement substance use. Our critical discourse approach illuminates how a variety of substances are positioned as tools for self-improvement. In reconceptualising enhancement substance use, we ask what different substances can be positioned as providing enhancement? How are they positioned as tools for achieving enhancement or self-improvement goals? What discursive repertoires are employed to achieve these aims? MethodsForty interviews were conducted with people who use substances, such as ayahuasca, psilocybin, cocaine, alcohol, nootropics and non-prescription pharmaceuticals, including Adderall and modafinil. To explore the meanings of and motivations for substance consumption, we apply the sociocognitive approach (SCA) pioneered by Teun van Dijk (2014; 2015) and examine language through the triangulation of cognition, discourse and society. We analyse how different substances are positioned as tools for achieving enhancement or self-improvement goals. ResultsWe identify three distinct discursive repertoires that frame substance use as enhancement: the discourse of transformation, the discourse of healing and the discourse of productivity. When accounting for enhancement substance use, our participants employ a number of discursive strategies, including ideological polarisation or ‘othering’, analogies, examples, maxims, metaphors and figurative speech. We also find evidence of interdiscursivity with most participants drawing on more than one discourse when speaking about how substances are positioned as providing enhancement. ConclusionWe conclude that the concept of enhancement has wider applicability than current understandings allow. We argue that if we reframe all substance use as providing enhancement or achieving a self-improvement goal, we have the potential to destigmatise substance use and eliminate the over-simplistic binaries that surround it.

Deep metagenomics examines the oral microbiome during dental caries, revealing novel taxa and co-occurrences with host molecules.

Dental caries, the most common chronic infectious disease worldwide, has a complex etiology involving the interplay of microbial and host factors that are not completely understood. In this study, the oral microbiome and 38 host cytokines and chemokines were analyzed across 23 children with caries and 24 children with healthy dentition. De novo assembly of metagenomic sequencing obtained 527 metagenome-assembled genomes (MAGs), representing 150 bacterial species. Forty-two of these species had no genomes in public repositories, thereby representing novel taxa. These new genomes greatly expanded the known pangenomes of many oral clades, including the enigmatic Saccharibacteria clades G3 and G6, which had distinct functional repertoires compared to other oral Saccharibacteria. Saccharibacteria are understood to be obligate epibionts, which are dependent on host bacteria. These data suggest that the various Saccharibacteria clades may rely on their hosts for highly distinct metabolic requirements, which would have significant evolutionary and ecological implications. Across the study group, Rothia, Neisseria, and Haemophilus spp. were associated with good dental health, whereas Prevotella spp., Streptococcus mutans, and Human herpesvirus 4 (Epstein-Barr virus [EBV]) were more prevalent in children with caries. Finally, 10 of the host immunological markers were significantly elevated in the caries group, and co-occurrence analysis provided an atlas of potential relationships between microbes and host immunological molecules. Overall, this study illustrated the oral microbiome at an unprecedented resolution and contributed several leads for further study that will increase the understanding of caries pathogenesis and guide therapeutic development.

Single-cell RNA sequencing confirms IgG transcription and limited diversity of VHDJH rearrangements in proximal tubular epithelial cells

Increasing evidence has confirmed that immunoglobulins (Igs) can be expressed in non-B cells. Our previous work demonstrated that mesangial cells and podocytes express IgA and IgG, respectively. The aim of this work was to reveal whether proximal tubular epithelial cells (PTECs) express Igs. High-throughput single-cell RNA sequencing (scRNA-seq) detected Igs in a small number of PTECs, and then we combined nested PCR with Sanger sequencing to detect the transcripts and characterize the repertoires of Igs in PTECs. We sorted PTECs from the normal renal cortex of two patients with renal cancer by FACS and further confirmed their identify by LRP2 gene expression. Only the transcripts of the IgG heavy chain were successfully amplified in 91/111 single PTECs. We cloned and sequenced 469 VHDJH transcripts from 91 single PTECs and found that PTEC-derived IgG exhibited classic VHDJH rearrangements with nucleotide additions at the junctions and somatic hypermutations. Compared with B cell-derived IgG, PTEC-derived IgG displayed less diversity of VHDJH rearrangements, predominant VH1-24/DH2-15/JH4 sequences, biased VH1 usage, centralized VH gene segment location at the 3′ end of the genome and non-Gaussian distribution of the CDR3 length. These results demonstrate that PTECs can express a distinct IgG repertoire that may have implications for their role in the renal tubular epithelial-mesenchymal transition.

TCR Repertoires in Graft-Versus-Host-Disease (GVHD)-Target Tissues Reveals Tissue Specificity of the Alloimmune Response

TCR Repertoires in Graft-Versus-Host-Disease (GVHD)-Target Tissues Reveals Tissue Specificity of the Alloimmune Response

The Nordic Balance Revisited: Differentiation and the Foreign Policy Repertoires of the Nordic States

Nordic governments frequently broadcast their ambition to do more together on the international stage. The five Nordic states (Denmark, Finland, Iceland, Sweden and Norway) also share many basic goals as foreign policy actors, including a steadfast and vocal commitment to safeguarding the ‘rules-based international order.’ Why then, do we not see more organized Nordic foreign policy collaboration, for example in the form of a joint ‘grand strategy’ on core foreign policy issues, or in relation to great powers and international organizations? In this article, we draw on Charles Tilly’s concept of ‘repertoires’ to address the discrepancy between ambitions and developments in Nordic foreign policy cooperation, highlighting how the bundles of policy instruments—repertoires—that each Nordic state has developed over time take on an identity-defining quality. We argue that the Nordic states have invested in and become attached to their foreign policy differences, niches, and ‘brands.’ On the international scene, and especially when interacting with significant other states, they tend not only to stick to what they know how to do and are accustomed to doing but also to promote their national rather than their Nordic profile. While Nordic cooperation forms part of all the five states’ foreign policy repertoire in specific policy areas, these are marginal compared to the distinctive repertoires on which each Nordic state rely in relation to more powerful states. It is therefore unlikely that we will see a ‘common order’ among the Nordic states in the foreign policy domain in the near future.

Inhibitory Receptor Trap: A Platform for Discovery of Inhibitory Receptors That Utilize Inositol Lipid and Phosphotyrosine Phosphatase Effectors.

Among the areas of most impactful recent progress in immunology is the discovery of inhibitory receptors and the subsequent translation of this knowledge to the clinic. Although the original and canonical member of this family is FcγRIIB, more recent studies defined PD1 as an inhibitory receptor that constrains T cell immunity to tumors. These studies led to development of “checkpoint blockade” immunotherapies (CBT) for cancers in which PD1 interactions with its ligand are blocked. Unfortunately, although very effective in some patients, only a small proportion respond to this therapy. This suggests that additional as yet undescribed inhibitory receptors exist, which could be exploited. Here, we describe a new platform, termed inhibitory receptor trap (IRT), for discovery of members of this family. The approach takes advantage of the fact that many of the known inhibitory receptors mediate signaling by phospho-immunoreceptor tyrosine-based inhibition motif (ITIM) mediated recruitment of Src Homology 2 (SH2) domain-containing phosphatases including the SH2 domain-containing inositol phosphatase SHIP1 encoded by the INPP5D gene and the SH2 domain-containing phosphotyrosine phosphatases SHP1 and SHP2 encoded by the PTPN6 and PTPN11 genes respectively. Here, we describe the IRT discovery platform in which the SH2 domains of inhibitory phosphatases are used for affinity-based isolation and subsequent identification of candidate effectors via immunoblotting and high sensitivity liquid chromatography–mass spectrometry. These receptors may represent alternative targets that can be exploited for improved CBT. Salient observations from these studies include the following: SH2 domains derived from the respective phosphatases bind distinct sets of candidates from different cell types. Thus, cells of different identity and different activation states express partially distinct repertoires of up and downstream phosphatase effectors. Phosphorylated PD1 binds not only SHP2 but also SHIP1, thus the latter may be important in its inhibitory function. B cell antigen receptor signaling leads predominantly to CD79 mono-phosphorylation as indicated by much greater binding to LynSH2 than Syk(SH2)2. This balance of ITAM mono- versus bi-phosphorylation likely tunes signaling by varying activation of inhibitory (Lyn) and stimulatory (Syk) pathways.

A Review of Current Knowledge on Staphylococcus agnetis in Poultry.

Simple SummaryThis literature review provides a synthesis and evaluation of the current knowledge on Staphylococcus agnetis (S. agnetis) and its implications in poultry pathology. Recent studies revealed that S. agnetis can cause bacterial chondronecrosis with osteomyelitis (BCO), endocarditis, and septicemia in broiler chickens. Lameness constitutes one of the major health and welfare problems causing huge economic losses in the poultry industry. To date, a range of infectious and non-infectious factors have been associated with lameness in poultry. Among bacteria of the genus Staphylococcus, Staphylococcus aureus is the main species associated with locomotor problems. This contrasts with S. agnetis, which until recently had not been considered as a poultry pathogen. Previously only reported in cattle, S. agnetis has expanded its host range to chickens, and due to its unique characteristics has become recognized as a new emerging pathogen. The genotypic and phenotypic similarities between S. agnetis and other two staphylococci (S. hyicus and S. chromogenes) make this pathogen capable of escaping recognition due to misidentification. Although a significant amount of research on S. agnetis has been conducted, many facts about this novel species are still unknown and further studies are required to understand its full significance in poultry pathology.This review aims to summarize recent discoveries and advancements regarding the characteristics of Staphylococcus agnetis (S. agnetis) and its role in poultry pathology. S. agnetis is an emerging pathogen that was primarily associated with mastitis in dairy cattle. After a presumed host jump from cattle to poultry, it was identified as a pathological agent in broiler chickens (Gallus gallus domesticus), causing lameness induced by bacterial chondronecrosis with osteomyelitis (BCO), septicemia, and valvular endocarditis. Economic and welfare losses caused by lameness are global problems in the poultry industry, and S. agnetis has been shown to have a potential to induce high incidences of lameness in broiler chickens. S. agnetis exhibits a distinct repertoire of virulence factors found in many different staphylococci. It is closely related to S. hyicus and S. chromogenes, hence infections caused by S. agnetis may be misdiagnosed or even undiagnosed. As there are very few reports on S. agnetis in poultry, many facts about its pathogenesis, epidemiology, routes of transmission, and the potential impacts on the poultry industry remain unknown.

Compaction and control-the role of chromosome-organizing proteins in Streptomyces.

Chromosomes are dynamic entities, whose organization and structure depend on the concerted activity of DNA-binding proteins and DNA-processing enzymes. In bacteria, chromosome replication, segregation, compaction and transcription are all occurring simultaneously, and to ensure that these processes are appropriately coordinated, all bacteria employ a mix of well-conserved and species-specific proteins. Unusually, Streptomyces bacteria have large, linear chromosomes and life cycle stages that include multigenomic filamentous hyphae and unigenomic spores. Moreover, their prolific secondary metabolism yields a wealth of bioactive natural products. These different life cycle stages are associated with profound changes in nucleoid structure and chromosome compaction, and require distinct repertoires of architectural-and regulatory-proteins. To date, chromosome organization is best understood during Streptomyces sporulation, when chromosome segregation and condensation are most evident, and these processes are coordinated with synchronous rounds of cell division. Advances are, however, now being made in understanding how chromosome organization is achieved in multigenomic hyphal compartments, in defining the functional and regulatory interplay between different architectural elements, and in appreciating the transcriptional control exerted by these 'structural' proteins.

‘Put some balls on that woman’: Gendered repertoires of inequality in screen composers’ careers

This study contributes to debates about gendered career outcomes in the creative industries using data collected in interviews with Australian screen composers. We identify how gendered inequalities are legitimated through professional norms by comparing the responses of screen composers on barriers to women’s advancement. The article explores how three distinct interpretive repertoires help reproduce the gender inequality regime present in the screen composition field. These repertoires are ‘art vs. equality’, where working towards equality can be framed as antithetical to artistic ideals; ‘gendered music’, where men and women are posited as making fundamentally different types of music; and ‘confidence’, where men are framed as innately possessing certain entrepreneurial skills vital to success in the creative industries, while women both shoulder the blame for not possessing such skills and recognize the risks inherent for them in performing confidence. By focusing on repertoires, this study describes the means by which gender‐based discrimination is made overt and offered justification among screen composers, posing challenges to organizations and individuals seeking to address gender inequality in the profession.

News Consumption across Media Platforms and Content

AbstractIn a changing information environment in which people increasingly select a combination of media platforms to consume news, scholars have taken a more comprehensive approach in measuring news consumption by examining news media repertoires. This study specifically (1) examines news repertoires of young people, based on their combined usage of media platforms and news content preferences; and (2) examines their variation due to social background characteristics. Results from a survey of Dutch adolescents (N = 1,084; age 16 to 21) reveal four distinct news repertoires: labeled minimalists, omnivores, traditionalists, and online news users. Findings further suggest that platform-based news repertoires are related to preferences for specific news content. Finally, this study contributes to the digital divide literature by demonstrating that inequalities in news media usage related to education do not seem to apply to younger citizens.

Identification of genes that contribute to fitness of African and Global clades of Salmonella Enteritidis during infection of macrophages

Non-typhoidal Salmonella (NTS) usually cause gastroenteritis in humans, but in recent years NTS have begun to cause epidemics of bloodstream infections in Africa. Salmonella Enteritidis is the second most common serovar associated with this invasive form of NTS disease (iNTS) in Africa. To establish a systemic infection, Salmonella must survive and replicate within host cells, with macrophages being a primary target. Genomic characterisation of S. Enteritidis isolates from human bloodstream has identified two new clades that are unique to Africa and distinct from the Global Epidemic clade. The African S. Enteritidis clades exhibit genomic degradation, and possess a distinct prophage repertoire and are multi-drug resistant. However, little is known about the virulence factors that allow African S. Enteritidis to cause systemic infection in susceptible hosts. We screened libraries of random insertion mutants of African and Global S. Enteritidis by transposon insertion sequencing (TIS), and identified about 280 genes belonging to each clade that contribute to bacterial survival and replication in murine macrophages. The genes were associated with 5 pathogenicity-islands, or encoded the global regulators PhoPQ and OmpR-EnvZ. Experiments are ongoing to investigate the role in intra-macrophage replication of genes that are uniquely identified in African Salmonella. It is hoped that our findings will contribute to a greater understanding of African Salmonella infection biology, and that some of the virulence-associated genes could be potential targets for novel therapeutics.

EGFR/Ras-induced CCL20 production modulates the tumour microenvironment

BackgroundThe activation of the EGFR/Ras-signalling pathway in tumour cells induces a distinct chemokine repertoire, which in turn modulates the tumour microenvironment.MethodsThe effects of EGFR/Ras on the expression and translation of CCL20 were analysed in a large set of epithelial cancer cell lines and tumour tissues by RT-qPCR and ELISA in vitro. CCL20 production was verified by immunohistochemistry in different tumour tissues and correlated with clinical data. The effects of CCL20 on endothelial cell migration and tumour-associated vascularisation were comprehensively analysed with chemotaxis assays in vitro and in CCR6-deficient mice in vivo.ResultsTumours facilitate progression by the EGFR/Ras-induced production of CCL20. Expression of the chemokine CCL20 in tumours correlates with advanced tumour stage, increased lymph node metastasis and decreased survival in patients. Microvascular endothelial cells abundantly express the specific CCL20 receptor CCR6. CCR6 signalling in endothelial cells induces angiogenesis. CCR6-deficient mice show significantly decreased tumour growth and tumour-associated vascularisation. The observed phenotype is dependent on CCR6 deficiency in stromal cells but not within the immune system.ConclusionWe propose that the chemokine axis CCL20–CCR6 represents a novel and promising target to interfere with the tumour microenvironment, and opens an innovative multimodal strategy for cancer therapy.