Real-World Treatment Patterns and Effectiveness of Targeted and Immune Checkpoint Inhibitor-Based Systemic Therapy in BRAF Mutation-Positive NSCLC.

Introduction: BRAF mutations (present in 2%-3% of NSCLC) are a known oncogenic driver and emerging therapeutic target. There is a scarcity of real-world data describing the clinical characteristics, treatment patterns, and effectiveness of targeted BRAF-inhibiting and immune checkpoint inhibitor (ICI)-based systemic therapies, yet this is required for appropriate treatment decisions that optimize patient outcome. Methods: Demographic, clinical, treatment, and outcome data of patients with BRAF mutation-positive NSCLC diagnosed between 2018 and 2022 were identified from the Glans-Look Lung Cancer Research database and included in this analysis. Results: A total of 53 BRAF mutation-positive patients were identified (V600E, n = 35; non-V600E, n = 18). Furthermore, 46 patients (87%) were diagnosed with metastatic disease, of whom 61% were treated with systemic anticancer therapy, which significantly improved overall survival (34.1 versus 2.2 mo, p = 0.01). ICI-based regimens were found to have effectiveness in the first-line setting for both V600E and non-V600E cohorts (objective response rate: 38%-43%; real-world calculations of median progression-free survival: 10.5-10.8 mo, respectively). Dual-targeted BRAF/MEK inhibition was also found to have effectiveness in the first-line setting for V600E patients (objective response rate: 33%, real-world calculations of median progression-free survival: 15.2 mo). Conclusions: This study of real-world patients with BRAF mutations confirms the importance of effective systemic therapies. Both dual-targeted BRAF/MEK inhibition and ICI-based regimens have evidence of benefit in this population revealing that real-world populations can experience similar clinical response and outcome to clinical trial cohorts on these treatment regimens. Future studies to clarify the role of co-mutations on response to both dual-targeted BRAF/MEK inhibition and ICI-based regimens may be important to treatment selection and optimization of patient outcome.

Defining the Genes Required for Survival of Mycobacterium bovis in the Bovine Host Offers Novel Insights into the Genetic Basis of Survival of Pathogenic Mycobacteria.

Tuberculosis has severe impacts on both humans and animals. Understanding the genetic basis of survival of both Mycobacterium tuberculosis, the human-adapted species, and Mycobacterium bovis, the animal-adapted species, is crucial to deciphering the biology of both pathogens. There are several studies that identify the genes required for survival of M. tuberculosis in vivo using mouse models; however, there are currently no studies probing the genetic basis of survival of M. bovis in vivo. In this study, we utilize transposon insertion sequencing in M. bovis AF2122/97 to determine the genes required for survival in cattle. We identify genes encoding established mycobacterial virulence functions such as the ESX-1 secretion system, phthiocerol dimycocerosate (PDIM) synthesis, mycobactin synthesis, and cholesterol catabolism that are required in vivo. We show that, as in M. tuberculosis H37Rv, phoPR is required by M. bovis AF2122/97 in vivo despite the known defect in signaling through this system. Comparison to studies performed in species that are able to use carbohydrates as an energy source, such as M. bovis BCG and M. tuberculosis, suggests that there are differences in the requirement for genes involved in cholesterol import (mce4 operon) and oxidation (hsd). We report a good correlation with existing mycobacterial virulence functions but also find several novel virulence factors, including genes involved in protein mannosylation, aspartate metabolism, and glycerol-phosphate metabolism. These findings further extend our knowledge of the genetic basis of survival in vivo in bacteria that cause tuberculosis and provide insight for the development of novel diagnostics and therapeutics. IMPORTANCE This is the first report of the genetic requirements of an animal-adapted member of the Mycobacterium tuberculosis complex (MTBC) in a natural host. M. bovis has devastating impacts on cattle, and bovine tuberculosis is a considerable economic, animal welfare, and public health concern. The data highlight the importance of mycobacterial cholesterol catabolism and identify several new virulence factors. Additionally, the work informs the development of novel differential diagnostics and therapeutics for TB in both human and animal populations.

Real-World Management and Outcomes of Crizotinib-Treated ROS1-Rearranged NSCLC: A Retrospective Canadian Cohort.

The use, safety and effectiveness of crizotinib as part of the management of ROS1-rearranged NSCLC patients in a real-world Canadian clinical cohort was the focus of this retrospective review. Twenty-one ROS1-rearranged patients with advanced/metastatic disease receiving crizotinib between 2014-2020 were identified; crizotinib demonstrated tolerability and effectiveness in this population where outcomes were similar to those described in other crizotinib-treated real-world cohorts, but lower than those of the PROFILE 1001 clinical trial population. Systemic anti-cancer therapy prior to crizotinib initiation occurred in half of the study cohort, with platin-pemetrexed and immune checkpoint inhibitors being most common. Platin-pemetrexed showed good effectiveness in this cohort, but despite high prevalence of upregulated PD-L1 expression, immune checkpoint inhibitors showed poor effectiveness in his cohort. Among all systemic therapies received, crizotinib showed the most effective disease control, although longer intervals between diagnosis and crizotinib initiation were more common among those showing a lack of clinical response to crizotinib, and patients with brain metastases at the time of crizotinib initiation also showed increased diagnosis to crizotinib initiation intervals and decreased clinical response to crizotinib. This study reveals crizotinib has clinical benefit, but timely identification of ROS1-rearrangements and initiation targeted therapies appears important to maximize outcome in this population.

A Real-World Evaluation of Atezolizumab Plus Platinum-Etoposide Chemotherapy in Patients With Extensive-Stage SCLC in Canada.

INTRODUCTION: The real-world data evaluating treatment outcomes of atezolizumab plus carboplatin-etoposide chemotherapy (atezolizumab) for extensive-stage SCLC (ESCLC) are lacking. Our objective was to evaluate real-world outcomes of ESCLC treated with atezolizumab. METHODS: A retrospective analysis of provincial patients with ESCLC who started first-line (1L) systemic treatment was conducted. We primarily evaluated the progression-free survival (PFS) and overall survival (OS) outcomes in association with atezolizumab compared with platinum-etoposide chemotherapy (chemotherapy) while adjusting for relevant demographic and clinical factors. Adverse events (AEs) during 1L were evaluated. RESULTS: A total of 67 patients were identified. Of the 34 patients who received atezolizumab, 24% had Eastern Cooperative Oncology Group performance status greater than or equal to 2, approximately 50% were more than or equal to 65 years, 21% received cisplatin-etoposide chemotherapy before atezolizumab, and 12% had thoracic radiation (tRT).Within the atezolizumab versus chemotherapy group, the median PFS equals to 6.0 versus 4.3 months (p = 0.03) whereas OS = 12.8 versus 7.1 months (p = 0.01). Relative to chemotherapy, the hazard ratio (95% confidence interval) for PFS was 0.53 (0.28-1.02) and OS was 0.42 (0.20-0.88) with atezolizumab. tRT compared with no tRT receipt correlated with reduced death risk (hazard ratio [95% confidence interval] = 0.33 [0.13-0.88]).AE-related treatment withdrawal with atezolizumab was 32% and 15% with chemotherapy (p = 0.02). Within the tRT subgroup, 25% versus 20% in atezolizumab versus chemotherapy group, respectively, discontinued 1L owing to AE. CONCLUSIONS: This is the first real-world study revealing comparable survival with that in the IMpower133 trial. Treatment discontinuation from AEs was higher with atezolizumab among Canadian patients with ESCLC. Our data suggest safe use of tRT and chemoimmunotherapy, but its efficacy for ESCLC warrants further study.

Retrospective Real-World Outcomes for Patients With ALK-Rearranged Lung Cancer Receiving ALK Receptor Tyrosine Kinase Inhibitors.

INTRODUCTION: This study explored the use, safety, and efficacy of initial use of an ALK-inhibiting targeted therapy (ALK tyrosine kinase inhibitor [TKI]) in patients with ALK-rearranged NSCLC in a population-based, real-world clinical population within the province of Alberta, Canada. METHODS: Demographic, clinical, treatment, and outcome data of the patients with advanced or metastatic ALK-rearranged NSCLC receiving their first ALK TKI between 2014 and 2019 were included in the analysis. RESULTS: A total of 92 patients with ALK-rearranged NSCLC treated with ALK TKI (78% crizotinib, 22% alectinib) were identified. In the ALK-rearranged cohort, 1-year survival rate was 73% and median overall survival (OS) and progression-free survival (PFS) were 48.5 months and 17.0 months, respectively. An objective response rate of 49% was observed, and adverse events were reported in 70% of the patients, primarily of low grade (84%). Case-matched comparison to patients with ALK-wildtype disease treated with cytotoxic chemotherapy revealed the benefit of ALK TKI in the context of an ALK rearrangement (ALK-rearranged versus ALK-wildtype) (median post-treatment initiation OS: 46.8 versus 14.2 mo, p < 0.001). Outcomes, measured from the time of ALK TKI initiation, differed by Eastern Cooperative Oncology Group (ECOG) (ECOG < 2 versus ECOG ≥ 2) (median OS: not reached versus 6.8 mo, p < 0.001; median PFS 17.6 versus 7.4 mo, p = 0.02), disease presentation (relapsed versus de novo) (median PFS: 30.8 versus 15.0 mo, p = 0.04), and brain metastasis onset (brain metastases development during ALK TKI versus baseline brain metastases) (not reached versus 12.8 mo, p = 0.04). CONCLUSIONS: Clinical trials have firmly established that ALK TKIs are safe, well tolerated, and effective; these findings reveal that their impact in a real-world setting is just as profound. The availability and use of ALK TKI therapies contribute to the impressive gains in survival experienced by contemporary patients with ALK-rearranged disease, rendering patients with this oncodriven form of NSCLC among the longest surviving patients with lung cancer.

The Role of TLR2 and TLR4 in Recognition and Uptake of the Apicomplexan Parasite Eimeria bovis and Their Effects on NET Formation.

BACKGROUND: Bovine polymorphonuclear neutrophils (PMN) constitutively express the Toll-like receptors (TLRs) TLR2 and TLR4 and have been shown to generate Neutrophil extracellular traps (NETs) upon exposure to Eimeria bovis. The present work investigated the role of TLR2 and TLR4 in the recognition and uptake of E. bovis sporozoites, IL-8 production and neutrophil extracellular trap (NET) formation. METHODS: TLR expression was performed by flow cytometric analysis on PMN exposed to live carboxyfluorescein succinimidyl ester (CFSE)-stained sporozoites. Supernatants of PMN exposed to different E. bovis sporozoite preparations and antigens in the absence or presence of TLR antibodies were assessed for IL-8 secretion. Cells were exposed to sporozoite preparations and assessed for the activation of transcription factor NF-κB using a luciferase reporter assay. Immunofluorescence analysis was done to investigate TLR2 and TLR4 surface expression and NET formation on bovine PMN exposed to vital sporozoites. RESULTS: we observed significantly increased TLR2 and TLR4 expression with a mean increase in expression that was greater for TLR2 than TLR4. This upregulation neither inhibited nor promoted sporozoite phagocytosis by bovine PMN. Live sporozoites together with anti-TLR2 mAb resulted in a significant enhancement of IL-8 production. NF-κB activation was more strongly induced in TLR2-HEK cells than in TLR4/MD2-HEK cells exposed to heat-killed sporozoites and antigens. Immunofluorescence analysis showed TLR-positive signals on the surface of PMN and concomitant NET formation. CONCLUSIONS: This is the first report on E. bovis-induced concomitant TLR2 and TLR4 expression during bovine PMN-derived NETosis.

Single Nucleotide Polymorphisms in the Bovine TLR2 Extracellular Domain Contribute to Breed and Species-Specific Innate Immune Functionality.

Recent evidence suggests that several cattle breeds may be more resistant to infection with the zoonotic pathogen Mycobacterium bovis. Our data presented here suggests that the response to mycobacterial antigens varies in macrophages generated from Brown Swiss (BS) and Holstein Friesian (HF) cattle, two breeds belonging to the Bos taurus family. Whole genome sequencing of the Brown Swiss genome identified several potential candidate genes, in particular Toll-like Receptor-2 (TLR2), a pattern recognition receptor (PRR) that has previously been described to be involved in mycobacterial recognition. Further investigation revealed single nucleotide polymorphisms (SNP) in TLR2 that were identified between DNA isolated from cells of BS and HF cows. Interestingly, one specific SNP, H326Q, showed a different genotype frequency in two cattle subspecies, Bos (B.) taurus and Bos indicus. Cloning of the TLR2 gene and subsequent gene-reporter and chemokine assays revealed that this SNP, present in BS and Bos indicus breeds, resulted in a significantly higher response to mycobacterial antigens as well as tri-acylated lipopeptide ligands in general. Comparing wild-type and H326Q containing TLR2 responses, wild-type bovine TLR2 response showed clear, diminished mycobacterial antigen responses compared to human TLR2, however bovine TLR2 responses containing H326Q were found to be partially recovered compared to human TLR2. The creation of human:bovine TLR2 chimeras increased the response to mycobacterial antigens compared to the full-length bovine TLR2, but significantly reduced the response compared to the full-length human TLR2. Thus, our data, not only present evidence that TLR2 is a major PRR in the mammalian species-specific response to mycobacterial antigens, but furthermore, that there are clear differences between the response seen in different cattle breeds, which may contribute to their enhanced or reduced susceptibility to mycobacterial infection.

Probing Differences in Gene Essentiality Between the Human and Animal Adapted Lineages of the Mycobacterium tuberculosis Complex Using TnSeq.

Members of the Mycobacterium tuberculosis complex (MTBC) show distinct host adaptations, preferences and phenotypes despite being >99% identical at the nucleic acid level. Previous studies have explored gene expression changes between the members, however few studies have probed differences in gene essentiality. To better understand the functional impacts of the nucleic acid differences between Mycobacterium bovis and Mycobacterium tuberculosis, we used the Mycomar T7 phagemid delivery system to generate whole genome transposon libraries in laboratory strains of both species and compared the essentiality status of genes during growth under identical in vitro conditions. Libraries contained insertions in 54% of possible TA sites in M. bovis and 40% of those present in M. tuberculosis, achieving similar saturation levels to those previously reported for the MTBC. The distributions of essentiality across the functional categories were similar in both species. 527 genes were found to be essential in M. bovis whereas 477 genes were essential in M. tuberculosis and 370 essential genes were common in both species. CRISPRi was successfully utilised in both species to determine the impacts of silencing genes including wag31, a gene involved in peptidoglycan synthesis and Rv2182c/Mb2204c, a gene involved in glycerophospholipid metabolism. We observed species specific differences in the response to gene silencing, with the inhibition of expression of Mb2204c in M. bovis showing significantly less growth impact than silencing its orthologue (Rv2182c) in M. tuberculosis. Given that glycerophospholipid metabolism is a validated pathway for antimicrobials, our observations suggest that target vulnerability in the animal adapted lineages cannot be assumed to be the same as the human counterpart. This is of relevance for zoonotic tuberculosis as it implies that the development of antimicrobials targeting the human adapted lineage might not necessarily be effective against the animal adapted lineage. The generation of a transposon library and the first reported utilisation of CRISPRi in M. bovis will enable the use of these tools to further probe the genetic basis of survival under disease relevant conditions.

Re-sensitization of Mycobacterium smegmatis to Rifampicin Using CRISPR Interference Demonstrates Its Utility for the Study of Non-essential Drug Resistance Traits.

A greater understanding of the genes involved in antibiotic resistance in Mycobacterium tuberculosis (Mtb) is necessary for the design of improved therapies. Clustered regularly interspaced short palindromic repeat interference (CRISPRi) has been previously utilized in mycobacteria to identify novel drug targets by the demonstration of gene essentiality. The work presented here shows that it can also be usefully applied to the study of non-essential genes involved in antibiotic resistance. The expression of an ADP-ribosyltransferase (Arr) involved in rifampicin resistance in Mycobacterium smegmatis was silenced using CRISPRi and the impact on rifampicin susceptibility was measured. Gene silencing resulted in a decrease in the minimum inhibitory concentration (MIC) similar to that previously reported in an arr deletion mutant. There is contradictory evidence for the toxicity of Streptococcus pyogenes dCas9 (dCas9Spy) in the literature. In this study the expression of dCas9Spy in M. smegmatis showed no impact on viability. Silencing was achieved with concentrations of the aTc inducer lower than previously described and with shorter induction times. Finally, designing small guide RNAs (sgRNAs) that target transcription initiation, or the early stages of elongation had the most impact on rifampicin susceptibility. This study demonstrates that CRISPRi based gene silencing can be as impactful as gene deletion for the study of non-essential genes and further contributes to the knowledge on the design and induction of sgRNAs for CRISPRi. This approach can be applied to other non-essential antimicrobial resistance genes such as drug efflux pumps.

Real-World Adherence to Guideline-Recommended Treatment for Small Cell Lung Cancer.

OBJECTIVES: The authors sought to quantify the treatment patterns and outcomes for limited-stage (LS) and extensive-stage (ES) small cell lung cancer (SCLC) in a real-world setting. METHODS: A review was conducted using the Glans-Look Research Database of patients with SCLC managed at a tertiary cancer center in Canada from 2010 to 2016. Adherence was defined as the commencement of planned SCLC treatment. Rate of compliance with the Alberta Health Services, American Society of Clinical Oncology, and National Comprehensive Cancer Network SCLC treatment guidelines was evaluated. Outcomes were analyzed using the Kaplan-Meier method and the Cox proportional hazards model. RESULTS: A total of 404 patients met our inclusion criteria, 31% were LS. The median age at first treatment receipt was 67 years. LS treatment consisted mostly of chemoradiation (62%). Chemoradiation and surgery±adjuvant predicted better survival (median, 32 and 40 mo, respectively) compared with no treatment. ES treatment consisted mostly of chemotherapy (90%). Chemotherapy and thoracic radiotherapy correlated with longer overall survival (13 vs. 9 mo, respectively) compared with chemotherapy alone. Prophylactic cranial irradiation receipt in LS (50%) and ES (20%) predicted favorable survivals than none (LS: hazard ratio, 0.48; 95% CI, 0.29-0.79; ES: hazard ratio, 0.48; 95% CI, 0.33-0.70). Approximately a quarter of relapsed LS and ES had second-line chemotherapy; improved survival with second line was observed only in ES (P<0.01). CONCLUSIONS: This study highlights high rates of guideline-recommended first treatment among the real-world LS and ES patients but it also revealed important outcome differences in relapsed LS and ES patients treated with second-line chemotherapy.

Impact of Asian ethnicity on outcome in metastatic EGFR-mutant non-small cell lung cancer.

AIM: To determine factors associated with survival in de novo stage IV, non-small cell lung cancer (NSCLC) patients possessing epidermal growth factor receptor mutations (EGFRmut+ ) receiving tyrosine kinase inhibitors (TKI) in the first-line setting. METHODS: The Glans-Look Lung Cancer Database was used to retrospectively review stage IV EGFRmut+ NSCLC patients diagnosed 2010-2016 receiving first-line TKI. Patients with overall survival times in the upper quartile (≥34 months) were designated "long-term survivors" (LTS), the remaining deemed "average-term survivors" and characteristics between these groups were compared in univariate analysis, and multivariable models constructed to determine predictors of outcome. RESULTS: Of 170 eligible patients, median overall survival was 21 months. LTS were significantly more likely to be of Asian ethnicity, be never-smokers and not possess brain or bone metastases at diagnosis. Asian and non-Asian patients were comparable, save for an increased propensity of Asian patients to be never smokers and have normal-range BMI. Multivariable analysis revealed Asian ethnicity [hazard ratio (HR) = 0.65; P = 0.016] and never-smoking history (HR = 0.65; P = 0.034) as indicators of improved outcome, and presence of brain metastasis at diagnosis an indicator of poor outcome (HR = 2.21; P < 0.001). CONCLUSIONS: Analysis of this population-based cohort identifies never-smoking history and absence of brain metastasis along with Asian ethnicity as an independent prognosticators of favorable outcome, and reveals Asian patients to be clinicopathologically similar to non-Asian patients. These findings suggest Asian patients represent a unique subpopulation within EGFRmut+ NSCLC who may possess different biological underpinnings of NSCLC.

Factors associated with early mortality in non-small cell lung cancer patients following systemic anti-cancer therapy: A 10 year population-based study.

OBJECTIVES: To investigate how clinical, demographic and treatment-related factors in non-small cell lung cancer (NSCLC) patients impact the risk of mortality in the 30 days following receipt of systemic anti-cancer therapies (SACT), and undertake a comprehensive review of the treatment decisions and experiences of a real-world population. MATERIALS AND METHODS: We reviewed NSCLC patients receiving SACT from 2005 to 2014, and captured in the Glans-Look Lung Cancer Database, which contains demographic, clinical, pathological, treatment and outcome data. The 30-day post-SACT mortality rate was calculated, and regimen changes in the last 14 days of life were identified. Univariate analysis and multivariate logistic regression were used to identify demographic, tumor and treatment-related factors that correlated with mortality risk. RESULTS: 1044 patients receiving ≥ 1 cycle of SACT in 2005-2014 were identified. 233 (22.3%) deaths occurred ≤ 30 days following SACT receipt; 32 (13.7%) of which had new SACT regimens ≤ 14 days prior to death. Risk of 30-day mortality and regimen changes at the end of life increased in association with being male [OR: 1.48 (1.12-1.95), p = 0.005], advanced disease at diagnosis [OR: 1.85 (1.19-2.88), p = 0.006], palliative-intent treatment [OR: 6.75 (3.88-11.77), p < 0.001], and use of EGFR-targeting agents [OR: 4.5 (3.27-6.18) p < 0.001]. Risk of early mortality decreased for never-smokers [OR: 0.62 (0.41-0.95), p = 0.028], and those receiving SACT in more recent years (2010-2014) [OR: 0.65 (0.49-0.86), p = 0.002]. CONCLUSION: Our findings identified several factors that affected the risk of early mortality in NSCLC patients following SACT. These results from a representative population provide insights regarding the benefits and risks of SACT and can serve to inform clinical and palliative best practices.

Comparison of Clinical Characteristics and Outcomes in Relapsed Versus De Novo Metastatic Non-Small Cell Lung Cancer.

OBJECTIVES: To compare the clinical characteristics and outcomes between relapsed and de novo metastatic non-small cell lung cancer (NSCLC). MATERIALS AND METHODS: We reviewed all NSCLC diagnoses between January 1999 and December 2013 in the institutional Glans-Look Lung Cancer Database, which contains demographic, clinical, pathologic, treatment, and outcome information. Patients with distant metastasis at diagnosis (American Joint Committee on Cancer [AJCC] eighth edition, stage IV), the "de novo" cohort, were compared with the "relapsed" cohort, consisting of patients diagnosed with early stage disease (stage I/II) undergoing curative intent treatment and subsequently experiencing metastatic relapse. Survival analysis, along with univariate and multivariable analysis was performed. RESULTS: A total of 185 relapsed and 3039 de novo patients were identified. Significantly different patterns of smoking history, histology, systemic therapy use, and disease extent were observed between the relapsed and de novo cohorts. Median overall survival from time of metastasis was significantly longer in relapsed than in de novo disease (8.9 vs. 3.7 mo, P<0.001). Relapsed patients demonstrated significant improvements in outcomes over time. In multivariate analysis, de novo metastatic disease continued to bode a worse prognosis (adjusted hazard ratio [HR], 1.4) as did male sex (HR, 1.2), never-smoking history (HR, 1.2), and presence of extrapulmonary metastases (HR, 1.3). Systemic therapy receipt conferred better outcome (HR, 0.4), although the impact of relapsed versus de novo disease on outcomes persisted regardless of systemic therapy receipt. CONCLUSIONS: Relapsed and de novo patients represent significantly different subpopulations within metastatic NSCLC with the latter exhibiting poorer survival. This information facilitates discussions about prognosis with patients and supports screening initiatives aimed at reducing de novo disease.

Comparison of cellular assays for TLR activation and development of a species-specific reporter cell line for cattle.

PRRs are sentinels of the innate immune system, with TLRs being the most important. Assays for TLR ligand interactions have been used to gain insights into their function and signaling pathways. As significant differences exist between species with regard to ligand recognition, it is necessary to adapt these tools for TLRs of other species. In the present work, we describe a species-specific cell-based assay adapted for the analysis of single PRRs. Human embryonic kidney 293T cells were stably transfected with the NF-κB-inducible reporter gene secreted embryonic alkaline phosphatase (SEAP) together with bovine TLR2. We compared the SEAP response with an existing luciferase NF-κB reporter assay for correlation with IL-8 production. A dose-dependent response was detected upon stimulation using both methods with good correlation to IL-8 secretion. Lower stimulant concentrations were detected by SEAP assay than IL-8 secretion. The luciferase assay produced high non-specific background for all ligand concentrations. Of all assays tested, we found the bovine-specific SEAP reporter assay to be the most convenient and delivered results in the shortest time. The developed reporter cell line would lend well to rapid, high-throughput TLR ligand screening for cattle.

Structural characterisation of Toll-like receptor 1 (TLR1) and Toll-like receptor 6 (TLR6) in elephant and harbor seals.

Pinnipeds are a diverse clade of semi-aquatic mammals, which act as key indicators of ecosystem health. Their transition from land to marine environments provides a complex microbial milieu, making them vulnerable to both aquatic and terrestrial pathogens, thereby contributing to pinniped population decline. Indeed, viral pathogens such as influenza A virus and phocine distemper virus (PDV) have been identified as the cause of several of these mass mortality events. Furthermore, bacterial infection with mammalian Brucella sp. and methicillin-resistant Staphylococcus aureus strains have also been observed in marine mammals, posing further risk to both co-habiting endangered species and public health. During these disease outbreaks, mortality rates have varied amongst different pinniped species. Analyses of innate immune receptors at the host-pathogen interface have previously identified variants which may drive these species-specific responses. Through a combination of both sequence- and structure-based methods, this study characterises members of the Toll-like receptor (TLR) 1 superfamily from both harbour and elephant seals, identifying variations which will help us to understand these species-specific innate immune responses, potentially aiding the development of specific vaccine-adjuvants for these species.

Effect of the synthetic Toll-like receptor ligands LPS, Pam3CSK4, HKLM and FSL-1 in the function of bovine polymorphonuclear neutrophils.

Toll-like receptors (TLR) are a family of pattern recognition receptors that sense microbial associated molecular patterns (MAMP) such as microbial membrane components and nucleic acids of bacterial origin. Polymorphonuclear neutrophils (PMN) are the first cell of the innate immune system to arrive at the site of infection or injury and elicit oxidative and non-oxidative microbicidal mechanisms. Observations in human and mouse suggest that TLR ligands can induce direct responses in PMN. So far, there is no information of the effect of synthetic TLR ligands on the response of bovine PMN. The objective of this study was to evaluate the functional response of bovine PMN incubated with four synthetic TLR ligands: ultrapure LPS (TLR4), Pam(3)CSK(4) (TLR2/1), HKLM (TLR2) and FSL-1 (TLR2/6). The results show that all the ligands increment cells size as identified by changes in the FSC-SSC as part of the flow cytometric analysis. Interestingly, only Pam(3)CSK(4) consistently induced a calcium influx, increased ROS production and secretion of gelatinase granules, whereas no response was seen using other ligands. Furthermore, exposure of bovine PMN to ultrapure LPS, Pam(3)CSK(4), HKLM or FSL-1 for 24 hours did not impact on apoptosis of these cells. Our data provide evidence for a selective response of bovine PMNs to TLR ligands.

Two TIR-like domain containing proteins in a newly emerging zoonotic Staphylococcus aureus strain sequence type 398 are potential virulence factors by impacting on the host innate immune response.

Staphylococcus aureus, sequence type (ST) 398, is an emerging pathogen and the leading cause of livestock-associated methicillin-resistant S. aureus infections in Europe and North America. This strain is characterized by high promiscuity in terms of host-species and also lacks several traditional S. aureus virulence factors. This does not, however, explain the apparent ease with which it crosses species-barriers. Recently, TIR-domain containing proteins (Tcps) which inhibit the innate immune response were identified in some Gram-negative bacteria. Here we report the presence of two proteins, S. aureus TIR-like Protein 1 (SaTlp1) and S. aureus TIR-like Protein 2 (SaTlp2), expressed by ST398 which contain domain of unknown function 1863 (DUF1863), similar to the Toll/IL-1 receptor (TIR) domain. In contrast to the Tcps in Gram-negative bacteria, our data suggest that SaTlp1 and SaTlp2 increase activation of the transcription factor NF-κB as well as downstream pro-inflammatory cytokines and immune effectors. To assess the role of both proteins as potential virulence factors knock-out mutants were created. These showed a slightly enhanced survival rate in a murine infectious model compared to the wild-type strain at one dose. Our data suggest that both proteins may act as factors contributing to the enhanced ability of ST398 to cross species-barriers.

Replacement of two aminoacids in the bovine Toll-like receptor 5 TIR domain with their human counterparts partially restores functional response to flagellin.

Flagellin potently induces inflammatory responses in mammalian cells by activating Toll-like receptor (TLR) 5. Recently, we were able to show that stimulation of bovine TLR5 resulted in neither NFκB signalling nor CXCL8 production. Like other TLRs, TLR5 recruits signalling molecules to its intracellular TIR domain, leading to inflammatory responses. Analysis of available TLR5 sequences revealed substitutions in all artiodactyl sequences at amo acid (AA) position 798 and 799. Interestingly, a putative binding site for PI3K was identified at tyrosine 798 in the human TLR5 TIR domain, analogous to the PI3K recruitment domain in the IL-1 receptor. Mutation of the artiodactyl residues at position 798, 799 or both with their corresponding human counterparts partially restored the response of bovine (bo)TLR5 to flagellin as well as phosphorylation of PI3K. Together, our results suggest a potential lack of phosphorylation of F798 and H799 in boTLR5 partially explains the lack in observed response.

Do progenitor cells from different tissue have the same phenotype?

The purpose of this work was to validate isolation methods for sheep mesenchymal stem cells (MSC) from different sources and to explore the hypothesis that MSC exhibit markers of the same phenotype independent from tissue source. Cells derived from ovine bone marrow, synovial membrane and adipose tissue were characterized using the following markers: CD44, CD45, CD11b and MHC-I. The isolated MSC were cultivated, went through osteogenic, chondrogenic and adipogenic differentiation, and were characterized by flow cytometry using mouse anti-ovine CD44, CD45 and MHC-I monoclonal antibody (mAb), and mouse anti-bovine CD11b mAb. Ovine MSC from all three sources differentiated under chondorgenic, osteogenic and adipogenic conditions. Also, MSC from the three tissues were found to express CD44 and MHC-I but lack of CD11b and CD45. The results obtained revealed that our isolation methods for the different tissues tested are valid and that MSC from the three sources studied have same immunophenotic characteristics.