Staphylococcus aureus Infection and Persistence in Chronic Rhinosinusitis: Focus on Leukocidin ED

Chronic rhinosinusitis (CRS) is thought to be a multifactorial disease that includes a direct involvement of bacteria that trigger inflammation and contribute to CRS pathogenesis. Staphylococcus aureus infection and persistence is associated with chronic rhinosinusitis (CRS), and it may be particularly relevant in the form with nasal polyps (CRSwNP). The large array of exotoxins deployed by S. aureus is instrumental for the bacterium to warrant its infection and dissemination in different human body districts. Here, we analyze the common Th2 environment in CRSwNP and prospect a possible dynamic role played by S. aureus leukocidins in promoting this chronic inflammation, considering leukocidin ED (LukED) as a strong prototype candidate worth of therapeutic investigation. CCR5 is an essential target for LukED to exert its cytotoxicity towards T cells, macrophages and dendritic cells. Therefore, CCR5 blockade might be an interesting therapeutic option for CRS and, more specifically, persistent and relapsing CRSwNP. In this perspective, the arsenal of CCR5 antagonists being developed to inhibit HIV-1 entry (CCR5 being the major HIV-1 co-receptor) could be easily repurposed for CRS therapeutic investigation. Finally, direct targeting of LukED by neutralizing antibodies could represent an important additional solution to S. aureus infection.

4121 The beneficial, anti-fibrotic effects of chemokine receptor 2 and 5 antagonists on fat-exposed mouse primary hepatic stellate cells (pHSCs)

OBJECTIVES/GOALS: Non-alcoholic steatohepatitis (NASH) is a leading cause of cirrhosis in the world for which no anti-fibrotic therapies exist. We hypothesized that BMS-22 and maraviroc (MVC), chemokine receptor 2 (CCR2) and 5 (CCR5) antagonists, respectively, would diminish the fibrogenic activity of "fat-exposed" murine pHSCs. METHODS/STUDY POPULATION: pHSCs were isolated from livers of 6 week old male mice following 4 weeks on a NASH-inducing choline-deficient high fat diet (CDAHFD, “fat-exposed”) or standard diet (SD) and passaged in vitro. Early passage (6-12) pHSCs were plate-adhered and TGF-b-treated (10ng/mL) to maximally activate their pro-fibrogenic genes, collagen 1α1 (Col1A1), tissue inhibitor of metalloproteinase 1 (TIMP1), or α-smooth muscle actin (ACTA2). CDAHFD and SD pHSCs were then treated for 48 hours with increasing doses of BMS-22 or MVC (range: 0.3-120ng/mL) to determine (1) the degree of attenuation of the pro-fibrogenic response as measured by qPCR of fibrogenic genes (Col1A1, TIMP1,ACTA2); (2) enhancement of a fibrolytic response as measured by qPCR of matrix metalloproteinases (MMP) 2, 9 and 13 genes; and (3) pHSC migration using the scratch assay. Cell viability and CCR2 and CCR5 gene expression in response to escalating doses of antagonists were also measured. RESULTS/ANTICIPATED RESULTS: Plate- and TGF-b activated CDAHFD pHSCs had a 2-fold greater, dose-dependent attenuation of their pro-fibrogenic activity in response to BMS-CCR2-22 and MVC, when compared with plate- and TGF-b activated SD pHSCs, as measured by reductions in collagen 1α1 (Col1A1) and α-smooth muscle actin (ACTA2) gene expression. TIMP1 gene expression was unaffected by drug treatment for 48 hours. Cell viability was not affected up to doses of 30ng/mL of each drug. pHSCs also demonstrated a dose-dependent increase in CCR2, CCR5 and MMP-9 gene expression in response to surface receptor antagonism. Migration assays comparing CDAHFD and SD pHSCs in response to escalating doses of MVC and BMS-22 are ongoing and expected to demonstrate a significantly decreased migratory capacity of CDAHFD pHSCs than SD pHSCs in response to therapy, reflecting the increased susceptibility of the “fat-exposed” pHSCs to anti-fibrotic therapy than normal pHSCs. DISCUSSION/SIGNIFICANCE OF IMPACT: Anti-fibrotic drugs that dampen pro-fibrogenic activities of “fat-exposed” pHSCs are urgently needed. CCR2 and CCR5 antagonists, BMS-22 and MVC, respectively, can selectively dampen the pro-fibrogenic response of fat-exposed pHSCs, and must be considered for future trials in human NASH. CONFLICT OF INTEREST DESCRIPTION: Dr. Jill Smith has a patent licensing agreement with Immune Therapeutics, Inc.

The human tissue-resident CCR5+ T cell compartment maintains protective and functional properties during inflammation

CCR5 is thought to play a central role in orchestrating migration of cells in response to inflammation. CCR5 antagonists can reduce inflammatory disease processes, which has led to an increased interest in using CCR5 antagonists in a wide range of inflammation-driven diseases. Paradoxically, these antagonists appear to function without negatively affecting host immunity at barrier sites. We reasoned that the resolution to this paradox may lie in the CCR5+ T cell populations that permanently reside in tissues. We used a single-cell analysis approach to examine the human CCR5+ T cell compartment in the blood, healthy, and inflamed mucosal tissues to resolve these seemingly contradictory observations. We found that 65% of the CD4 tissue-resident memory T (TRM) cell compartment expressed CCR5. These CCR5+ TRM cells were enriched in and near the epithelial layer and not only limited to TH1-type cells but also contained a large TH17-producing and a stable regulatory T cell population. The CCR5+ TRM compartment was stably maintained even in inflamed tissues including the preservation of TH17 and regulatory T cell populations. Further, using tissues from the CHARM-03 clinical trial, we found that CCR5+ TRM are preserved in human mucosal tissue during treatment with the CCR5 antagonist Maraviroc. Our data suggest that the human CCR5+ TRM compartment is functionally and spatially equipped to maintain barrier immunity even in the absence of CCR5-mediated, de novo T cell recruitment from the periphery.

Human CCL3L1 copy number variation, gene expression, and the role of the CCL3L1-CCR5 axis in lung function

Background: The CCL3L1-CCR5 signaling axis is important in a number of inflammatory responses, including macrophage function, and T-cell-dependent immune responses. Small molecule CCR5 antagonists exist, including the approved antiretroviral drug maraviroc, and therapeutic monoclonal antibodies are in development. Repositioning of drugs and targets into new disease areas can accelerate the availability of new therapies and substantially reduce costs. As it has been shown that drug targets with genetic evidence supporting their involvement in the disease are more likely to be successful in clinical development, using genetic association studies to identify new target repurposing opportunities could be fruitful. Here we investigate the potential of perturbation of the CCL3L1-CCR5 axis as treatment for respiratory disease. Europeans typically carry between 0 and 5 copies of CCL3L1 and this multi-allelic variation is not detected by widely used genome-wide single nucleotide polymorphism studies. Methods: We directly measured the complex structural variation of CCL3L1 using the Paralogue Ratio Test and imputed (with validation) CCR5d32 genotypes in 5,000 individuals from UK Biobank, selected from the extremes of the lung function distribution, and analysed DNA and RNAseq data for CCL3L1 from the 1000 Genomes Project. Results: We confirmed the gene dosage effect of CCL3L1 copy number on CCL3L1 mRNA expression levels. We found no evidence for association of CCL3L1 copy number or CCR5d32 genotype with lung function. Conclusions: These results suggest that repositioning CCR5 antagonists is unlikely to be successful for the treatment of airflow obstruction.

Human CCL3L1 copy number variation, gene expression, and the role of the CCL3L1-CCR5 axis in lung function

Background: The CCL3L1-CCR5 signaling axis is important in a number of inflammatory responses, including macrophage function, and T-cell-dependent immune responses. Small molecule CCR5 antagonists exist, including the approved antiretroviral drug maraviroc, and therapeutic monoclonal antibodies are in development. Repositioning of drugs and targets into new disease areas can accelerate the availability of new therapies and substantially reduce costs. As it has been shown that drug targets with genetic evidence supporting their involvement in the disease are more likely to be successful in clinical development, using genetic association studies to identify new target repurposing opportunities could be fruitful. Here we investigate the potential of perturbation of the CCL3L1-CCR5 axis as treatment for respiratory disease. Europeans typically carry between 0 and 5 copies of CCL3L1 and this multi-allelic variation is not detected by widely used genome-wide single nucleotide polymorphism studies. Methods: We directly measured the complex structural variation of CCL3L1 using the Paralogue Ratio Test and imputed (with validation) CCR5del32 genotypes in 5,000 individuals from UK Biobank, selected from the extremes of the lung function distribution, and analysed DNA and RNAseq data for CCL3L1 from the 1000 Genomes Project. Results: We confirmed the gene dosage effect of CCL3L1 copy number on CCL3L1 mRNA expression levels. We found no evidence for association of CCL3L1 copy number or CCR5del32 genotype with lung function. Conclusions: These results suggest that repositioning CCR5 antagonists is unlikely to be successful for the treatment of airflow obstruction.

Human CCL3L1 copy number variation, gene expression, and the role of the CCL3L1-CCR5 axis in lung function

The CCL3L1-CCR5 signaling axis is important in a number of inflammatory responses, including macrophage function, and T-cell-dependent immune responses. Small molecule CCR5 antagonists exist, including the approved antiretroviral drug maraviroc, and therapeutic monoclonal antibodies are in development. Repositioning of drugs and targets into new disease areas can accelerate the availability of new therapies and substantially reduce costs. As it has been shown that drug targets with genetic evidence supporting their involvement in the disease are more likely to be successful in clinical development, using genetic association studies to identify new target repurposing opportunities could be fruitful. Here we investigate the potential of perturbation of the CCL3L1-CCR5 axis as treatment for respiratory disease. Europeans typically carry between 0 and 5 copies of CCL3L1 and this multi-allelic variation is not detected by widely used genome-wide single nucleotide polymorphism studies. We directly measured the complex structural variation of CCL3L1 using the Paralogue Ratio Test (PRT) and imputed (with validation) CCR5del32 genotypes in 5,000 individuals from UK Biobank, selected from the extremes of the lung function distribution, and analysed DNA and RNAseq data for CCL3L1 from the 1000 Genomes Project. We confirmed the gene dosage effect of CCL3L1 copy number on CCL3L1 mRNA expression levels. We found no evidence for association of CCL3L1 copy number or CCR5del32 genotype with lung function suggesting that repositioning CCR5 antagonists is unlikely to be successful for the treatment of airflow obstruction.