ABSTRACT
BACKGROUND: Sacral neuromodulation is an effective treatment for fecal incontinence in the long term. Efficacy is typically assessed using bowel diary, symptom severity, and quality-of-life questionnaires, and "success" is defined as more than 50% improvement in these measures. However, patient satisfaction may be a more meaningful and individualized measure of treatment efficacy. OBJECTIVE: To assess patient-reported satisfaction with long-term sacral neuromodulation and compare it to the frequently applied efficacy measures. DESIGN: An observational study of a prospectively maintained database. SETTING: A single tertiary pelvic floor referral unit. PATIENTS: Data from 70 patients (68 women, median age 69 [60-74] years) were available. The median time since implantation was 11 (9-14) years. Nineteen patients reported inactive neuromodulation devices. MAIN OUTCOME MEASURES: Bowel diaries, the Manchester Health Questionnaire, and the St. Mark's Incontinence Score were recorded at baseline, after percutaneous nerve evaluation, and at the last follow-up. Patient-reported satisfaction, using a 0% to 100% visual analog scale, with treatment since implantation (overall) and in the 2 weeks preceding completion of the last outcome measures (current) were also assessed. RESULTS: Satisfaction was significantly higher in those with active sacral neuromodulation devices (75% vs 20%, p < 0.001) at follow-up. No significant relationships exist between symptom improvement using conventional measures and patient-reported satisfaction. Current satisfaction was not associated with changes in bowel diary data after percutaneous nerve evaluation. Despite improvements in the St. Mark's Incontinence Score and Manchester Health Questionnaire below the 50% improvement threshold used to define "success," patients reported high (80%) satisfaction. LIMITATIONS: Retrospective design with gaps in the available data. CONCLUSIONS: High patient satisfaction with sacral neuromodulation can be achieved; however, the response to percutaneous nerve evaluation may not predict treatment satisfaction in the long term. The change in questionnaire results, which measure the use of compensatory behaviors and quality-of-life impact, may better correspond to treatment satisfaction. SATISFACCIN A LARGO PLAZO EN LOS PACIENTES CON LA NEUROMODULACIN SACRA PARA LA INCONTINENCIA FECAL EXPERIENCIA DE UN NICO CENTRO TERCIARIO: ANTECEDENTES:La neuromodulación sacra es un tratamiento eficaz para la incontinencia fecal a largo plazo. La eficacia suele evaluarse mediante cuestionarios sobre la frecuencia diaria intestinal, la gravedad de los síntomas o la calidad de vida, y el "éxito" se define como una mejoría >50% en estas medidas. Sin embargo, la satisfacción del paciente puede ser una medida más significativa e individualizada de la eficacia del tratamiento.OBJETIVO:Evaluar la satisfacción a largo plazo de los pacientes con la neuromodulación sacra y compararla con las medidas de eficacia aplicadas con frecuencia.DISEÑO:Estudio observacional de una base de datos mantenida prospectivamente.LUGAR:Unidad terciaria única de referencia de suelo pélvico.PACIENTES:Se dispuso de datos de 70 pacientes (68 mujeres, mediana de edad 69 [60-74]). La mediana de tiempo transcurrido desde la implantación fue de 11 (9-14) años. Diecinueve pacientes informaron de dispositivos de neuromodulación inactivos.PRINCIPALES MEDIDAS DE VALORACIÓN:Diarios intestinales, el Cuestionario de Salud de Manchester y la Puntuación de Incontinencia de St Marks registrados al inicio, tras la evaluación percutánea del nervio y en el último seguimiento. Los pacientes informaron de su satisfacción, utilizando una escala analógica visual de 0%-100%, con el tratamiento desde la implantación (global) y en las dos semanas anteriores a la realización de las últimas medidas de resultado (actual).RESULTADOS:La satisfacción fue significativamente mayor en los pacientes con dispositivos de neuromodulación sacra activos (75% frente a 20%, p < 0,001) durante el seguimiento. No existen relaciones significativas entre la mejoría de los síntomas mediante medidas convencionales y la satisfacción comunicada por el paciente. La satisfacción actual no se asoció con los cambios en los datos de la frecuencia diaria intestinal tras la evaluación percutánea de los nervios. A pesar de que las mejoras en la puntuación de incontinencia de St Mark y el Cuestionario de Salud de Manchester se situaron por debajo del umbral de mejora del 50% utilizado para definir el "éxito", los pacientes declararon un alto grado de satisfacción (80%).LIMITACIONES:Retrospectivo con lagunas en los datos disponibles.CONCLUSIONES:Puede lograrse una alta satisfacción de los pacientes con la neuromodulación sacra; sin embargo, la respuesta a la evaluación percutánea del nervio puede no predecir la satisfacción con el tratamiento a largo plazo. El cambio en los resultados del cuestionario, que mide el uso de conductas compensatorias y el impacto en la calidad de vida, puede corresponder mejor a la satisfacción con el tratamiento. (Traducción-Dr. Ingrid Melo ).
Subject(s)
Electric Stimulation Therapy , Fecal Incontinence , Patient Satisfaction , Quality of Life , Humans , Fecal Incontinence/therapy , Fecal Incontinence/psychology , Female , Middle Aged , Patient Satisfaction/statistics & numerical data , Male , Aged , Treatment Outcome , Electric Stimulation Therapy/methods , Electric Stimulation Therapy/instrumentation , Surveys and Questionnaires , Lumbosacral Plexus , Tertiary Care Centers , Prospective StudiesABSTRACT
We have a firearm public health crisis in the United States, with firearm injuries being the leading cause of death in children. The state of pediatric firearm violence will be summarized through a synopsis of an expert panel of pediatric-focused advanced practice registered nurses. A review of related statistics, policy initiatives, programs, screening tools, and resources to support providers to intervene with patients, parents, and caregivers is summarized. Strategies to identify and intervene with all youth and families are described. All pediatric providers must take action against pediatric firearm violence and work to develop care strategies and health policy changes to combat this growing epidemic.
ABSTRACT
Heterotrimeric G proteins transduce extracellular chemical messages to generate appropriate intracellular responses. Point mutations in GNAO1, encoding the G protein αo subunit, have been implicated in a pathogenic condition characterized by seizures, movement disorders, intellectual disability, and developmental delay (GNAO1 disorder). However, the effects of these mutations on G protein structure and function are unclear. Here, we report the effects of 55 mutations on Gαo conformation, thermostability, nucleotide binding, and hydrolysis, as well as interaction with Gßγ subunits, receptors, and effectors. Our effort reveals four functionally distinct groups of mutants, including one group that sequesters receptors and another that sequesters Gßγ, both acting in a genetically dominant manner. These findings provide a more comprehensive understanding of disease-relevant mutations and reveal that GNAO1 disorder is likely composed of multiple mechanistically distinct disorders that will likely require multiple therapeutic strategies.
Subject(s)
Movement Disorders , Humans , Mutation/genetics , Movement Disorders/genetics , Point Mutation , GTP-Binding Proteins/metabolism , GTP-Binding Protein alpha Subunits, Gi-Go/genetics , GTP-Binding Protein alpha Subunits, Gi-Go/metabolismABSTRACT
The DNA mismatch repair pathway is involved in the identification, excision, and repair of base-base mismatches and indel loops in the genome. Mismatch repair deficiency occurs in approximately 20% of all cancers and results in a type of DNA damage called microsatellite instability. In 2017, the immune checkpoint inhibitor, Pembrolizumab, an anti-PD-1 therapy, was approved for use in all unresectable or metastatic tumours that were mismatch repair deficient or had high microsatellite instability regardless of tissue origin. This landmark approval was the first time a drug had been approved in a site agnostic way, but accumulating data has revealed that up to 50% of mismatch repair deficient tumours are refractory to treatment and there is a huge amount of variability in the therapeutic benefit amongst responders. Several mechanisms of resistance to immune checkpoint blockade for mismatch repair deficient cancers have been identified but our understanding of what is driving resistance in a proportion of patients remains lacking. In this review article, we discuss the emerging mechanisms of resistance which may enable optimal stratification of patients for treatment with immune checkpoint inhibitors in the future.
Subject(s)
Colorectal Neoplasms , Immune Checkpoint Inhibitors , Humans , Immune Checkpoint Inhibitors/pharmacology , Immune Checkpoint Inhibitors/therapeutic use , DNA Mismatch Repair , Biomarkers, Tumor/genetics , Microsatellite Instability , Colorectal Neoplasms/pathologyABSTRACT
Heterotrimeric guanine nucleotide-binding proteins (G proteins) that function as molecular switches for cellular growth and metabolism are activated by GTP and inactivated by GTP hydrolysis. In uveal melanoma, a conserved glutamine residue critical for GTP hydrolysis in the G protein α subunit is often mutated in Gαq or Gα11 to either leucine or proline. In contrast, other glutamine mutations or mutations in other Gα subtypes are rare. To uncover the mechanism of the genetic selection and the functional role of this glutamine residue, we analyzed all possible substitutions of this residue in multiple Gα isoforms. Through cell-based measurements of activity, we showed that some mutants were further activated and inactivated by G protein-coupled receptors. Through biochemical, molecular dynamics, and nuclear magnetic resonance-based structural studies, we showed that the Gα mutants were functionally distinct and conformationally diverse, despite their shared inability to hydrolyze GTP. Thus, the catalytic glutamine residue contributes to functions beyond GTP hydrolysis, and these functions include subtype-specific, allosteric modulation of receptor-mediated subunit dissociation. We conclude that G proteins do not function as simple on-off switches. Rather, signaling emerges from an ensemble of active states, a subset of which are favored in disease and may be uniquely responsive to receptor-directed ligands.
Subject(s)
Glutamine , Heterotrimeric GTP-Binding Proteins , Catalytic Domain , Glutamine/genetics , Heterotrimeric GTP-Binding Proteins/metabolism , Mutation , Guanosine Triphosphate/chemistryABSTRACT
The DNA-damage response is a complex signaling network that guards genomic integrity. The microtubule cytoskeleton is involved in the repair of DNA double-strand breaks; however, little is known about which cytoskeleton-related proteins are involved in DNA repair and how. Using quantitative proteomics, we discovered that microtubule associated proteins MAP7 and MAP7D1 interact with several DNA repair proteins including DNA double-strand break repair proteins RAD50, BRCA1 and 53BP1. We observed that downregulation of MAP7 and MAP7D1 leads to increased phosphorylation of p53 after γ-irradiation. Moreover, we determined that the downregulation of MAP7D1 leads to a strong G1 arrest and that the downregulation of MAP7 and MAP7D1 in G1 arrested cells negatively affects DNA repair, recruitment of RAD50 to chromatin and localization of 53BP1 to the sites of damage. These findings describe for the first time a novel function of MAP7 and MAP7D1 in cell cycle regulation and repair of DNA double-strand breaks.
ABSTRACT
Background: Mutations in the tumor suppressor gene Adenomatous Polyposis Coli (APC) are found in 80% of sporadic colorectal cancer (CRC) tumors and are also responsible for the inherited form of CRC, Familial adenomatous polyposis (FAP). Methods: To identify novel therapeutic strategies for the treatment of APC mutated CRC, we generated a drug screening platform that incorporates a human cellular model of APC mutant CRC using CRISPR-cas9 gene editing and performed an FDA-approved drug screen targeting over 1000 compounds. Results: We have identified the group of HMG-CoA Reductase (HMGCR) inhibitors known as statins, which cause a significantly greater loss in cell viability in the APC mutated cell lines and in in vivo APC mutated patient derived xenograft (PDX) models, compared to wild-type APC cells. Mechanistically, our data reveals this new synthetic lethal relationship is a consequence of decreased Wnt signalling and, ultimately, a reduction in the level of expression of the anti-apoptotic protein Survivin, upon statin treatment in the APC-mutant cells only. This mechanism acts via a Rac1 mediated control of beta-catenin. Conclusion: Significantly, we have identified a novel synthetic lethal dependence between APC mutations and statin treatment, which could potentially be exploited for the treatment of APC mutated cancers.
ABSTRACT
The lack of effective therapies remains one of the main challenges for malignant pleural mesothelioma (MPM). In this perspective, drug repositioning could accelerate the identification of novel treatments. We screened 1170 FDA-approved drugs on a SV40-immortalized mesothelial (MeT-5A) and five MPM (Mero-14, Mero-25, IST-Mes2, NCI-H28 and MSTO-211H) cell lines. Biological assays were carried out for 41 drugs, showing the highest cytotoxicity and for whom there were a complete lack of published literature in MPM. Cytotoxicity and caspase activation were evaluated with commercially available kits and cell proliferation was assayed using MTT assay and by clonogenic activity with standard protocols. Moreover, the five most effective drugs were further evaluated on patient-derived primary MPM cell lines. The most active molecules were cephalomannine, ouabain, alexidine, thonzonium bromide, and emetine. Except for alexidine, these drugs inhibited the clonogenic ability and caspase activation in all cancer lines tested. The proliferation was inhibited also on an extended panel of cell lines, including primary MPM cells. Thus, we suggest that cephalomannine, ouabain, thonzonium bromide, and emetine could represent novel candidates to be repurposed for improving the arsenal of therapeutic weapons in the fight against MPM.
ABSTRACT
Oncolytic viruses are being tested in clinical trials, including in women with ovarian cancer. We use a drug-repurposing approach to identify existing drugs that enhance the activity of oncolytic adenoviruses. This reveals that carvedilol, a ß-arrestin-biased ß-blocker, synergises with both wild-type adenovirus and the E1A-CR2-deleted oncolytic adenovirus, dl922-947. Synergy is not due to ß-adrenergic blockade but is dependent on ß-arrestins and is reversed by ß-arrestin CRISPR gene editing. Co-treatment with dl922-947 and carvedilol causes increased viral DNA replication, greater viral protein expression and higher titres of infectious viral particles. Carvedilol also enhances viral efficacy in orthotopic, intraperitoneal murine models, achieving more rapid tumour clearance than virus alone. Increased anti-cancer activity is associated with an intratumoural inflammatory cell infiltrate and systemic cytokine release. In summary, carvedilol augments the activity of oncolytic adenoviruses via ß-arrestins to re-wire cytokine networks and innate immunity and could therefore improve oncolytic viruses for cancer patient treatment.
Subject(s)
Adenoviridae , Carvedilol/pharmacology , Immunity, Innate , Oncolytic Virotherapy , Oncolytic Viruses , Ovarian Neoplasms/therapy , Adrenergic alpha-1 Receptor Antagonists/pharmacology , Adrenergic alpha-1 Receptor Antagonists/therapeutic use , Animals , Carvedilol/therapeutic use , Cell Line, Tumor , Female , Humans , Mice , Neoplasms, Experimental/drug therapy , Ovarian Neoplasms/immunology , Xenograft Model Antitumor Assays , beta-Arrestins/metabolismABSTRACT
BACKGROUND & AIMS: Substitution of lysine for glutamic acid at residu 167 in Transmembrane 6 superfamily member 2 (TM6SF2) is associated with fatty liver disease and reduced plasma lipid levels. Tm6sf2-/- mice replicate the human phenotype but were not suitable for detailed mechanistic studies. As an alternative model, we generated Tm6sf2-/- rats to determine the subcellular location and function of TM6SF2. METHODS: Two lines of Tm6sf2-/- rats were established using gene editing. Lipids from tissues and from newly secreted very low density lipoproteins (VLDLs) were quantified using enzymatic assays and mass spectrometry. Neutral lipids were visualized in tissue sections using Oil Red O staining. The rate of dietary triglyceride (TG) absorption and hepatic VLDL-TG secretion were compared in Tm6sf2-/- mice and in their wild-type littermates. The intracellular location of TM6SF2 was determined by cell fractionation. Finally, TM6SF2 was immunoprecipitated from liver and enterocytes to identify interacting proteins. RESULTS: Tm6sf2-/- rats had a 6-fold higher mean hepatic TG content (56.1 ± 28.9 9 vs 9.8 ± 3.9 mg/g; P < .0001) and lower plasma cholesterol levels (99.0 ± 10.5 vs 110.6 ± 14.0 mg/dL; P = .0294) than their wild-type littermates. Rates of appearance of dietary and hepatic TG into blood were reduced significantly in Tm6sf2-/- rats (P < .001 and P < .01, respectively). Lipid content of newly secreted VLDLs isolated from perfused livers was reduced by 53% (TG) and 62% (cholesterol) (P = .005 and P = .01, respectively) in Tm6sf2-/- mice. TM6SF2 was present predominantly in the smooth endoplasmic reticulum and endoplasmic reticulum-Golgi intermediate compartments, but not in Golgi. Both apolipoprotein B-48 and acyl-CoA synthetase long chain family member 5 physically interacted with TM6SF2. CONCLUSIONS: TM6SF2 acts in the smooth endoplasmic reticulum to promote bulk lipidation of apolipoprotein B-containing lipoproteins, thus preventing fatty liver disease.
Subject(s)
Membrane Proteins , Non-alcoholic Fatty Liver Disease , Animals , Membrane Proteins/metabolism , Mice , Non-alcoholic Fatty Liver Disease/metabolism , RatsABSTRACT
An early event in lung oncogenesis is loss of the tumour suppressor gene LIMD1 (LIM domains containing 1); this encodes a scaffold protein, which suppresses tumorigenesis via a number of different mechanisms. Approximately 45% of non-small cell lung cancers (NSCLC) are deficient in LIMD1, yet this subtype of NSCLC has been overlooked in preclinical and clinical investigations. Defining therapeutic targets in these LIMD1 loss-of-function patients is difficult due to a lack of 'druggable' targets, thus alternative approaches are required. To this end, we performed the first drug repurposing screen to identify compounds that confer synthetic lethality with LIMD1 loss in NSCLC cells. PF-477736 was shown to selectively target LIMD1-deficient cells in vitro through inhibition of multiple kinases, inducing cell death via apoptosis. Furthermore, PF-477736 was effective in treating LIMD1-/- tumours in subcutaneous xenograft models, with no significant effect in LIMD1+/+ cells. We have identified a novel drug tool with significant preclinical characterisation that serves as an excellent candidate to explore and define LIMD1-deficient cancers as a new therapeutic subgroup of critical unmet need.
Subject(s)
Carcinoma, Non-Small-Cell Lung/genetics , Intracellular Signaling Peptides and Proteins/deficiency , LIM Domain Proteins/deficiency , Lung Neoplasms/genetics , Animals , Carcinoma, Non-Small-Cell Lung/pathology , Female , Humans , Lung Neoplasms/pathology , Mice , Mice, Inbred NOD , Proof of Concept Study , TransfectionABSTRACT
INTRODUCTION: We used the plan-do-study-act (PDSA) framework to develop and implement an evidence-based clinical practice guideline (CPG) within an urban, tertiary children's referral center. METHODS: We developed an evidence-based CPG for appendicitis using iterative PDSA cycles. Similar CPGs from other centers were reviewed and modified for local implementation. Adjuncts included guideline-specific order sets and operative notes in the electronic medical record system. Outcomes included length of stay (LOS), 30-day readmissions, hospital costs, and patient and family experience (PFE) scores. Our team tracked outcome, process, and balancing measures using Statistical Process Charts. Outcome measures were compared over 2 fiscal quarters preimplementation and 3 fiscal quarters postimplementation, using interrupted time series, student t test, and chi-square tests when appropriate. RESULTS: LOS for simple (uncomplicated) appendicitis decreased to 0.87 days (interquartile range [IQR] 0.87-0.94 days) from 1.1 days (IQR 0.97-1.42 days). LOS for complicated appendicitis decreased to 4.96 days (IQR 4.95-6.15) from 5.58 days (IQR 5.16-6.09). This reduction equated to an average cost-savings of $1,122/patient. Thirty-day readmission rates have remained unchanged. PFE scores increased across all categories and have remained higher than national benchmarks. CONCLUSION: Development and Implementation of a CPG for pediatric appendicitis using the PDSA framework adds value to care provided within a large tertiary center.
ABSTRACT
High-grade serous cancer (HGSC) accounts for ~67% of all ovarian cancer deaths. Although initially sensitive to platinum chemotherapy, resistance is inevitable and there is an unmet clinical need for novel therapies that can circumvent this event. We performed a drug screen with 1177 FDA-approved drugs and identified the hydroxyquinoline drug, chloroxine. In extensive validation experiments, chloroxine restored sensitivity to both cisplatin and carboplatin, demonstrating broad synergy in our range of experimental models of platinum-resistant HGSC. Synergy was independent of chloroxine's predicted ionophore activity and did not relate to platinum uptake as measured by atomic absorption spectroscopy. Further mechanistic investigation revealed that chloroxine overrides DNA damage tolerance in platinum-resistant HGSC. Co-treatment with carboplatin and chloroxine (but not either drug alone) caused an increase in γH2AX expression, followed by a reduction in platinum-induced RAD51 foci. Moreover, this unrepaired DNA damage was associated with p53 stabilisation, cell cycle re-entry and triggering of caspase 3/7-mediated cell death. Finally, in our platinum-resistant, intraperitoneal in vivo model, treatment with carboplatin alone resulted in a transient tumour response followed by tumour regrowth. In contrast, treatment with chloroxine and carboplatin combined, was able to maintain tumour volume at baseline for over 4 months. In conclusion, our novel results show that chloroxine facilitates platinum-induced DNA damage to restore platinum sensitivity in HGSC. Since chloroxine is already licensed, this exciting combination therapy could now be rapidly translated for patient benefit.
Subject(s)
Chloroquinolinols/pharmacology , DNA Damage/drug effects , Drug Resistance, Neoplasm/drug effects , Ovarian Neoplasms/drug therapy , Platinum/pharmacology , Animals , Antineoplastic Agents/pharmacology , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Carboplatin/pharmacology , Cisplatin/pharmacology , Cystadenocarcinoma, Serous/drug therapy , Cystadenocarcinoma, Serous/pathology , Drug Resistance, Neoplasm/genetics , Female , Humans , Mice, Transgenic , Ovarian Neoplasms/geneticsABSTRACT
The DNA damage response (DDR) consists of multiple specialized pathways that recognize different insults sustained by DNA and repairs them where possible to avoid the accumulation of mutations. While loss of activity of genes in the DDR has been extensively associated with cancer predisposition and progression, in recent years it has become evident that there is a relationship between the DDR and cellular metabolism. The activity of the metabolic pathways can influence the DDR by regulating the availability of substrates required for the repair process and the function of its players. Additionally, proteins of the DDR can regulate the metabolic flux through the major pathways such as glycolysis, tricarboxylic acid cycle (TCA) and pentose phosphate pathway (PPP) and the production of reactive oxygen species (ROS). This newly discovered connection bears great importance in the biology of cancer and represents a new therapeutic opportunity. Here we describe the nature of the relationship between DDR and metabolism and its potential application in the treatment of cancer. Keywords: DNA repair, metabolism, mitochondria.
Subject(s)
DNA Repair , Metabolism , Clinical Trials as Topic , Homologous Recombination/genetics , Humans , Mitochondria/metabolism , Models, BiologicalABSTRACT
Objectives Malignant pleural mesothelioma (MPM) is an occupational disease mainly due to asbestos exposure. Effective therapies for MPM are lacking, making this tumour type a fatal disease. Materials and Methods In order to meet this need and in view of a future "drug repositioning" approach, here we screened five MPM (Mero-14, Mero-25, IST-Mes2, NCI-H28 and MSTO-211H) and one SV40-immortalized mesothelial cell line (MeT-5A) as a non-malignant model, with a library of 1170 FDA-approved drugs. Results Among several potential compounds, we found that fludarabine (F-araA) and, to a lesser extent, risedronic acid (RIS) were cytotoxic in MPM cells, in comparison to the non-malignant Met-5A cells. In particular, F-araA reduced the proliferation and the colony formation ability of the MPM malignant cells, in comparison to the non-malignant control cells, as demonstrated by proliferation and colony formation assays, in addition to measurement of the phospho-ERK/total-ERK ratio. We have shown that the response to F-araA was not dependent upon the expression of DCK and NT5E enzymes, nor upon their functional polymorphisms (rs11544786 and rs2295890, respectively). Conclusion This drug repositioning screening approach has identified that F-araA could be therapeutically active against MPM cells, in addition to other tumour types, by inhibiting STAT1 expression and nucleic acids synthesis. Further experiments are required to fully investigate this.
Subject(s)
Antineoplastic Agents/pharmacology , Mesothelioma/drug therapy , Pleural Neoplasms/drug therapy , Risedronic Acid/pharmacology , STAT1 Transcription Factor/antagonists & inhibitors , Vidarabine/analogs & derivatives , Cell Line , Cell Proliferation/drug effects , Cell Survival/drug effects , Drug Repositioning , Gene Expression Regulation, Neoplastic/drug effects , Humans , Mesothelioma/genetics , Mesothelioma/metabolism , Pleural Neoplasms/genetics , Pleural Neoplasms/metabolism , STAT1 Transcription Factor/metabolism , Vidarabine/pharmacologyABSTRACT
Endocannabinoids are host-derived lipid hormones that fundamentally impact gastrointestinal (GI) biology. The use of cannabis and other exocannabinoids as anecdotal treatments for various GI disorders inspired the search for mechanisms by which these compounds mediate their effects, which led to the discovery of the mammalian endocannabinoid system. Dysregulated endocannabinoid signaling was linked to inflammation and the gut microbiota. However, the effects of endocannabinoids on host susceptibility to infection has not been explored. Here, we show that mice with elevated levels of the endocannabinoid 2-arachidonoyl glycerol (2-AG) are protected from enteric infection by Enterobacteriaceae pathogens. 2-AG directly modulates pathogen function by inhibiting virulence programs essential for successful infection. Furthermore, 2-AG antagonizes the bacterial receptor QseC, a histidine kinase encoded within the core Enterobacteriaceae genome that promotes the activation of pathogen-associated type three secretion systems. Taken together, our findings establish that endocannabinoids are directly sensed by bacteria and can modulate bacterial function.
Subject(s)
Endocannabinoids/metabolism , Enterobacteriaceae/pathogenicity , Animals , Arachidonic Acids/chemistry , Arachidonic Acids/metabolism , Bacterial Adhesion , Bacterial Proteins/metabolism , Bacterial Secretion Systems/metabolism , Citrobacter rodentium/pathogenicity , Colon/microbiology , Colon/pathology , Endocannabinoids/chemistry , Enterobacteriaceae Infections/microbiology , Female , Gastrointestinal Microbiome , Glycerides/chemistry , Glycerides/metabolism , HeLa Cells , Host-Pathogen Interactions , Humans , Male , Mice, Inbred C57BL , Mice, Knockout , Monoacylglycerol Lipases/metabolism , Salmonella/pathogenicity , VirulenceABSTRACT
The DNA mismatch repair (MMR) pathway is responsible for the repair of base-base mismatches and insertion/deletion loops that arise during DNA replication. MMR deficiency is currently estimated to be present in 15-17% of colorectal cancer cases and 30% of endometrial cancers. MLH1 is one of the key proteins involved in the MMR pathway. Inhibition of a number of mitochondrial genes, including POLG and PINK1 can induce synthetic lethality in MLH1-deficient cells. Here we demonstrate for the first time that loss of MLH1 is associated with a deregulated mitochondrial metabolism, with reduced basal oxygen consumption rate and reduced spare respiratory capacity. Furthermore, MLH1-deficient cells display a significant reduction in activity of the respiratory chain Complex I. As a functional consequence of this perturbed mitochondrial metabolism, MLH1-deficient cells have a reduced anti-oxidant response and show increased sensitivity to reactive oxidative species (ROS)-inducing drugs. Taken together, our results provide evidence for an intrinsic mitochondrial dysfunction in MLH1-deficient cells and a requirement for MLH1 in the regulation of mitochondrial function.