| 1. |
- Ahmadi, Shahram, et al.
(författare)
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Similar immune responses to alpha1-oleate and Bacillus Calmette–Guérin treatment in patients with bladder cancer
- 2024
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Ingår i: Cancer Medicine. - 2045-7634. ; 13:7
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Tidskriftsartikel (refereegranskat)abstract
- Background: The molecular content of urine is defined by filtration in the kidneys and by local release from tissues lining the urinary tract. Pathological processes and different therapies change the molecular composition of urine and a variety of markers have been analyzed in patients with bladder cancer. The response to BCG immunotherapy and chemotherapy has been extensively studied and elevated urine concentrations of IL-1RA, IFN-α, IFN-γ TNF-α, and IL-17 have been associated with improved outcome. Methods: In this study, the host response to intravesical alpha 1-oleate treatment was characterized in patients with non-muscle invasive bladder cancer by proteomic and transcriptomic analysis. Results: Proteomic profiling detected a significant increase in multiple cytokines in the treatment group compared to placebo. The innate immune response was strongly activated, including IL-1RA and pro-inflammatory cytokines in the IL-1 family (IL-1α, IL-1β, IL-33), chemokines (MIP-1α, IL-8), and interferons (IFN-α2, IFN-γ). Adaptive immune mediators included IL-12, Granzyme B, CD40, PD-L1, and IL-17D, suggesting broad effects of alpha 1-oleate treatment on the tumor tissues. Conclusions: The cytokine response profile in alpha 1-oleate treated patients was similar to that reported in BCG treated patients, suggesting a significant overlap. A reduction in protein levels at the end of treatment coincided with inhibition of cancer-related gene expression in tissue biopsies, consistent with a positive treatment effect. Thus, in addition to killing tumor cells and inducing cell detachment, alpha 1-oleate is shown to activate a broad immune response with a protective potential.
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| 2. |
- Ambite, Inès, et al.
(författare)
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Active bacterial modification of the host environment through RNA polymerase II inhibition
- 2021
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Ingår i: Journal of Clinical Investigation. - 0021-9738. ; 131:4
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Tidskriftsartikel (refereegranskat)abstract
- Unlike pathogens, which attack the host, commensal bacteria create a state of friendly coexistence. Here, we identified a mechanism of bacterial adaptation to the host niche, where they reside. Asymptomatic carrier strains were shown to inhibit RNA polymerase II (Pol II) in host cells by targeting Ser2 phosphorylation, a step required for productive mRNA elongation. Assisted by a rare, spontaneous loss-of-function mutant from a human carrier, the bacterial NlpD protein was identified as a Pol II inhibitor. After internalization by host cells, NlpD was shown to target constituents of the Pol II phosphorylation complex (RPB1 and PAF1C), attenuating host gene expression. Therapeutic efficacy of a recombinant NlpD protein was demonstrated in a urinary tract infection model, by reduced tissue pathology, accelerated bacterial clearance, and attenuated Pol II-dependent gene expression. The findings suggest an intriguing, evolutionarily conserved mechanism for bacterial modulation of host gene expression, with a remarkable therapeutic potential.
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| 3. |
- Ambite, Ines, et al.
(författare)
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Bacterial suppression of RNA polymerase II-dependent host gene expression
- 2016
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Ingår i: Pathogens. - : MDPI AG. - 2076-0817. ; 5:3
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Forskningsöversikt (refereegranskat)abstract
- Asymptomatic bacteriuria (ABU) is a bacterial carrier state in the urinary tract that resembles commensalism at other mucosal sites. ABU strains often lack the virulence factors that characterize uropathogenic Escherichia coli (E. coli) strains and therefore elicit weak innate immune responses in the urinary tract. In addition, ABU strains are active modifiers of the host environment, which they influence by suppressing RNA polymerase II (Pol II)-dependent host gene expression. In patients inoculated with the ABU strain E. coli 83972, gene expression was markedly reduced after 24 h (>60% of all regulated genes). Specific repressors and activators of Pol II-dependent transcription were modified, and Pol II Serine 2 phosphorylation was significantly inhibited, indicating reduced activity of the polymerase. This active inhibition included disease–associated innate immune response pathways, defined by TLR4, IRF-3 and IRF-7, suggesting that ABU strains persist in human hosts by active suppression of the antibacterial defense. In a search for the mechanism of inhibition, we compared the whole genome sequences of E. coli 83972 and the uropathogenic strain E. coli CFT073. In addition to the known loss of virulence genes, we observed that the ABU strain has acquired several phages and identified the lytic Prophage 3 as a candidate Pol II inhibitor. Intact phage particles were released by ABU during in vitro growth in human urine. To address if Prophage 3 affects Pol II activity, we constructed a Prophage 3 negative deletion mutant in E. coli 83972 and compared the effect on Pol II phosphorylation between the mutant and the E. coli 83972 wild type (WT) strains. No difference was detected, suggesting that the Pol II inhibitor is not encoded by the phage. The review summarizes the evidence that the ABU strain E. coli 83972 modifies host gene expression by inhibition of Pol II phosphorylation, and discusses the ability of ABU strains to actively create an environment that enhances their persistence.
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| 4. |
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| 5. |
- Ambite, Ines, et al.
(författare)
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Fimbriae reprogram host gene expression - Divergent effects of P and type 1 fimbriae
- 2019
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Ingår i: PLoS Pathogens. - : Public Library of Science (PLoS). - 1553-7366 .- 1553-7374. ; 15:6, s. 1007671-1007671
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Tidskriftsartikel (refereegranskat)abstract
- Pathogens rely on a complex virulence gene repertoire to successfully attack their hosts. We were therefore surprised to find that a single fimbrial gene reconstitution can return the virulence-attenuated commensal strain Escherichia coli 83972 to virulence, defined by a disease phenotype in human hosts. E. coli 83972pap stably reprogrammed host gene expression, by activating an acute pyelonephritis-associated, IRF7-dependent gene network. The PapG protein was internalized by human kidney cells and served as a transcriptional agonist of IRF-7, IFN-β and MYC, suggesting direct involvement of the fimbrial adhesin in this process. IRF-7 was further identified as a potent upstream regulator (-log (p-value) = 61), consistent with the effects in inoculated patients. In contrast, E. coli 83972fim transiently attenuated overall gene expression in human hosts, enhancing the effects of E. coli 83972. The inhibition of RNA processing and ribosomal assembly indicated a homeostatic rather than a pathogenic end-point. In parallel, the expression of specific ion channels and neuropeptide gene networks was transiently enhanced, in a FimH-dependent manner. The studies were performed to establish protective asymptomatic bacteriuria in human hosts and the reconstituted E. coli 83972 variants were developed to improve bacterial fitness for the human urinary tract. Unexpectedly, P fimbriae were able to drive a disease response, suggesting that like oncogene addiction in cancer, pathogens may be addicted to single super-virulence factors.
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| 6. |
- Ambite, Ines, et al.
(författare)
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Molecular Basis of Acute Cystitis Reveals Susceptibility Genes and Immunotherapeutic Targets
- 2016
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Ingår i: PLoS Pathogens. - : Public Library of Science (PLoS). - 1553-7366 .- 1553-7374. ; 12:10
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Tidskriftsartikel (refereegranskat)abstract
- Tissue damage is usually regarded as a necessary price to pay for successful elimination of pathogens by the innate immune defense. Yet, it is possible to distinguish protective from destructive effects of innate immune activation and selectively attenuate molecular nodes that create pathology. Here, we identify acute cystitis as an Interleukin-1 beta (IL-1β)-driven, hyper-inflammatory condition of the infected urinary bladder and IL-1 receptor blockade as a novel therapeutic strategy. Disease severity was controlled by the mechanism of IL-1β processing and mice with intact inflammasome function developed a moderate, self-limiting form of cystitis. The most severe form of acute cystitis was detected in mice lacking the inflammasome constituents ASC or NLRP-3. IL-1β processing was hyperactive in these mice, due to a new, non-canonical mechanism involving the matrix metalloproteinase 7- (MMP-7). ASC and NLRP-3 served as transcriptional repressors of MMP7 and as a result, Mmp7 was markedly overexpressed in the bladder epithelium of Asc-/- and Nlrp3-/- mice. The resulting IL-1β hyper-activation loop included a large number of IL-1β-dependent pro-inflammatory genes and the IL-1 receptor antagonist Anakinra inhibited their expression and rescued susceptible Asc-/- mice from bladder pathology. An MMP inhibitor had a similar therapeutic effect. Finally, elevated levels of IL-1β and MMP-7 were detected in patients with acute cystitis, suggesting a potential role as biomarkers and immunotherapeutic targets. The results reproduce important aspects of human acute cystitis in the murine model and provide a comprehensive molecular framework for the pathogenesis and immunotherapy of acute cystitis, one of the most common infections in man. Trial Registration: The clinical studies were approved by the Human Ethics Committee at Lund University (approval numbers LU106-02, LU236-99 and Clinical Trial Registration RTP-A2003, International Committee of Medical Journal Editors, www.clinicaltrials.gov).
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| 7. |
- Ambite, Ines
(författare)
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Molecular determinants of disease severity in urinary tract infection
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In the urinary tract, Escherichia coli infection may result in life-threatening disease, or asymptomatic bacterial carriage, comparable to bacterial commensalism in the gut. Pathogenic strains trigger a disease provoking host response which differs depending on the infected organ. The diversity of the response reflects the virulence repertoire of the infecting strain and by the susceptibility of the host. During asymptomatic bacteriuria (ABU), the lack of clinical symptoms has been attributed to the loss of virulence by the strains. ABU strains have a reduced genome size and carry point mutations or deletions in virulence genes. In the prototype strain E. coli 83972 fimbrial gene clusters are affected by multiple point mutations (the papG adhesin gene) or large deletions (the fim gene cluster). As a result, the innate immune response to ABU strains is reduced. In addition, we made the discovery that asymptomatic carrier strains actively inhibit RNA Polymerase II (Pol II) Ser2 phosphorylation. Pol II is the enzyme required for the transcription of all mRNA in eukaryotes and its function is tightly regulated. E. coli 83972 suppresses Pol II-dependent host gene expression, including genes involved in immune activation. Compared to a broad chemical inhibitor, DRB, inhibition was more limited, suggesting a degree of specificity for a certain repertoire of host genes. Through this suppression of transcription, ABU strains may promote tissue integrity while inhibiting potentially destructive immune activation. NlpD was identified as a protein released by asymptomatic carrier strains with potent host gene expression inhibitory capacity. NlpD targeted the Pol II phosphorylation machinery by interacting with the biggest Pol II subunit, RPB1, and PAF1C in host cells. In treated mice, NlpD inhibited the destructive arm of innate immune activation and reduced bacterial loads. Our findings suggest that molecules of bacterial origin may be explored as therapies to reproduce the beneficial effects associated with ABU.The symptoms of acute cystitis, in contrast, are caused by an exaggerated inflammatory response triggered by infection. We now define acute cystitis as an IL-1β-driven, hyper-inflammatory disorder with atypical IL-1β processing through MMP-7. The results also suggest a genetic susceptibility factor in patients with severe and chronic cystitis, through mutations affecting ASC or NLRP3 expression. ASC and NLRP-3 were identified as negative regulators of MMP-7 expression and the identified molecular determinants and IL-1β and MMP-7 as novel targets for immunomodulatory therapy with potent effects in vivo as well as biomarkers for acute cystitis.In contrast to acute cystitis, acute pyelonephritis is a severe, sometimes life-threatening kidney infection with systemic involvement and risk of developing bacteremia. Uropathogenic E. coli strains initiate tissue attack of the renal pelvis thus starting disease pathogenesis. A normally protective innate immune signalling cascade, controlled by toll like receptor (TLR)4, is exaggerated explaining the acute disease and sometimes destructive, long-term effects. The response is determined, in part, by bacterial P fimbriae, their receptors and the quality of the signalling cascade that they activate, including several transcription factors. The transcription factor IRF-3 controls the protective arm of the innate immune response to kidney infection, and as a result, mice lacking Irf3 develop severe infection accompanied by urosepsis and renal abscess formation. We identify IRF-7 as a driving force for the disease response in Irf3-/- mice and development of renal pathology. We also define Irf7 as an immuno-therapeutic target that can be controlled with small interfering RNA (siRNA) to restore the balance of resistance versus pathology and prevent kidney damage.Finally, we show that P fimbriae influence the IRF-7 expression and the repertoire of downstream genes associated with acute pyelonephritis (APN). Specifically, P fimbriae were shown to act as IRF-7 agonists. The expression of functional P fimbriae was sufficient to reprogram host gene expression, through effects of PapG on the transcriptional machinery of the host. Paradoxically, the results suggest that a single “super virulence” factor may be sufficient to tilt the balance from peaceful coexistence to disease and for the host to recognize and respond to a strain that lacks most other virulence factors.
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| 8. |
- Ambite, Ines, et al.
(författare)
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Molecular determinants of disease severity in urinary tract infection
- 2021
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Ingår i: Nature Reviews Urology. - : Springer Science and Business Media LLC. - 1759-4812 .- 1759-4820. ; 18:8, s. 468-486
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Forskningsöversikt (refereegranskat)abstract
- The most common and lethal bacterial pathogens have co-evolved with the host. Pathogens are the aggressors, and the host immune system is responsible for the defence. However, immune responses can also become destructive, and excessive innate immune activation is a major cause of infection-associated morbidity, exemplified by symptomatic urinary tract infections (UTIs), which are caused, in part, by excessive innate immune activation. Severe kidney infections (acute pyelonephritis) are a major cause of morbidity and mortality, and painful infections of the urinary bladder (acute cystitis) can become debilitating in susceptible patients. Disease severity is controlled at specific innate immune checkpoints, and a detailed understanding of their functions is crucial for strategies to counter microbial aggression with novel treatment and prevention measures. One approach is the use of bacterial molecules that reprogramme the innate immune system, accelerating or inhibiting disease processes. A very different outcome is asymptomatic bacteriuria, defined by low host immune responsiveness to bacteria with attenuated virulence. This observation provides the rationale for immunomodulation as a new therapeutic tool to deliberately modify host susceptibility, control the host response and avoid severe disease. The power of innate immunity as an arbitrator of health and disease is also highly relevant for emerging pathogens, including the current COVID-19 pandemic.
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| 9. |
- Ambite, Ines, et al.
(författare)
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Susceptibility to urinary tract infection : Benefits and hazards of the antibacterial host response
- 2016
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Ingår i: Microbiology spectrum. - Washington, DC, USA : ASM Press. - 2165-0497. ; 4:3
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Forskningsöversikt (refereegranskat)abstract
- A paradigm shift is needed to improve and personalize the diagnosis of infectious disease and to select appropriate therapies. For many years, only the most severe and complicated bacterial infections received more detailed diagnostic and therapeutic attention as the efficiency of antibiotic therapy has guaranteed efficient treatment of patients suffering from the most common infections. Indeed, treatability almost became a rationale not to analyze bacterial and host parameters in these larger patient groups. Due to the rapid spread of antibiotic resistance, common infections like respiratory tract- or urinary-tract infections (UTIs) now pose new and significant therapeutic challenges. It is fortunate and timely that infectious disease research can offer such a wealth of new molecular information that is ready to use for the identification of susceptible patients and design of new suitable therapies. Paradoxically, the threat of antibiotic resistance may become a window of opportunity, by encouraging the implementation of new diagnostic and therapeutic approaches. The frequency of antibiotic resistance is rising rapidly in uropathogenic organisms and the molecular and genetic understanding of UTI susceptibility is quite advanced. More bold translation of the new molecular diagnostic and therapeutic tools would not just be possible but of great potential benefit in this patient group. This chapter reviews the molecular basis for susceptibility to UTI, including recent advances in genetics, and discusses the consequences for diagnosis and therapy. By dissecting the increasingly well-defined molecular interactions between bacteria and host and the molecular features of excessive bacterial virulence or host-response malfunction, it is becoming possible to isolate the defensive from the damaging aspects of the host response. Distinguishing "good" from "bad" inflammation has been a long-term quest of biomedical science and in UTI, patients need the "good" aspects of the inflammatory response to resist infection while avoiding the "bad" aspects, causing chronicity and tissue damage.
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| 10. |
- Ambite, Ines, et al.
(författare)
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The Genetics of Urinary Tract Infections and the Innate Defense of the Kidney and Urinary tract
- 2016
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Ingår i: Journal of pediatric genetics. - : Georg Thieme Verlag KG. - 2146-4596 .- 2146-460X. ; 5:1, s. 25-32
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Forskningsöversikt (refereegranskat)abstract
- The urinary tract is a sterile organ system. Urinary tract infections (UTIs) are common and often serious infections. Research has focused on uropathogen, environment, and host factors leading to UTI pathogenesis. A growing body of evidence exists implicating genetic factors that can contribute to UTI risks. In this review, we highlight genetic variations in aspects of the innate immune system critical to the host response to uropathogens. This overview includes genetic variations in pattern recognition receptor molecules, chemokines/cytokines, and neutrophil activation. We also comprehensively cover murine knockout models of UTI, genetic variations involved in renal scarring as a result of ascending UTIs, and asymptomatic bacteriuria.
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