POS0097 IDENTIFICATION OF NEW CANDIDATE DRUGS FOR PRIMARY SJÖGREN’S SYNDROME USING A DRUG REPURPOSING TRANSCRIPTOMIC APPROACH

Background

No immunomodulatory drug has ever demonstrated its efficacy in primary Sjögren’s Syndrome (pSS). Drug repurposing, or drug repositioning, refers to the use in another disease of an existing drug, originally approved or evaluated in a different disease.

Objectives

The objective of our study was to repurpose existing therapeutic drugs in pSS using a transcriptomic approach.

Methods

We generated pSS transcriptomic signatures from peripheral blood samples of patients with pSS compared to healthy controls in two cohorts (ASSESS and a Norwegian cohort) and data mined available pSS transcriptomic signatures in public databases. We compared each disease signature to transcriptomic signatures, obtained from the biological action of 2837 drugs, 2160 knock-in and 3799 knock-down genes, available in the Connectivity Map database. A median similarity score with regard to disease signatures was computed for each candidate drug/gene. Drugs and genes were selected if p<0.05 and similarity score >│80│. If this score is sufficiently high and statistically significant (>80, p<0.05), the tested drug or gene, mimics the signature of the disease. Conversely, if this score is sufficiently low and statistically significant (<-80, p<0.05), the tested drug or gene inverts the signature of the disease and might represent a potential treatment or therapeutic target of interest (Figure 1).

Figure 1.

Methods of drug-repurposing transcriptomic analysis (adapted from Toro-Dominguez et al, Arthritis Res Ther 2017;19:54)

Results

1091 peripheral blood transcriptomes were analyzed from 6 independent studies (906 patients with pSS and 185 healthy controls). Our analysis identified 11 transcriptomic drug signatures significantly associated with pSS signature. We identified 72 transcriptomic knock-in (11) or knock-down (61) gene signatures significantly associated with that of pSS, including 21 with a negative similarity score (Table 1).

Table 1.

Knock-down and knock-in genes significantly associated with the pSS transcriptomic signatures

Type ofexperimentSimilarity scoreGenesNumber of genesKnock-in+IFNG, DUSP28, IFNB1, LYN, BCL2L2, TNFRSF1A, CD40, BCL10, NLK, ZNF39810-SLC52A2111Knock-down+SLC25A14, GOLIM4, DTYMK, DCXR, RRM2, IMPA1, CLTB, F12, CAB39, ID1, ISOC1, UBAP1, HIGD2A, UFD1L, SOD2, BTG1, PRKCI, HIST2H2BE, NISCH, TEAD4, MTX2, TYK2, GTF2B, NDUFS7, NNT, ACADSB, GSTP1, HOMER2, SORBS3, PCK2, PHB2, PDXK, TES, TM9SF2, TBX2, HOXA6, KIF2C, MED1, NR2F6, CD14, BECN141-TM9SF3, E2F3, PRMT3, KD, PKN2, SUCLA2, CD44, GRN, SP3, ATP5S, MYCBP2, TRAF7, POLA2, ADRB2, PSMG1, PPP2R3C, PMAIP1, ETFA, ANKRD37, SPECC1L2061

Type I and II interferons were highly ranked (similarity score >99), and their overexpression mimicked the disease signature. CD40 appeared also as a very relevant target (similarity score = 98.8). Three drugs had a significant negative similarity score: ampicillin (-88.69, p=0.0019), amylocaine (-88.28, p=0.0026), and droxinostat (-85.42, p=0.0027). Droxinostat is a HDAC inhibitor. HDAC activity has been shown to be an essential element of the coactivation system for IFN-induced gene regulation and the IFN-induced innate immune response.

Conclusion

This first drug repositioning transcriptomic approach in Sjögren’s syndrome confirms the interest of targeting interferons and identifies histone deacetylases as potential therapeutic targets.

Acknowledgements

Investigators of the ASSESS cohort: Emmanuelle Dernis, Valerie Devauchelle-Pensec, Philippe Dieude, Jean-Jacques Dubost, Anne-Laure Fauchais, Vincent Goeb, Eric Hachulla, Pierre Yves Hatron, Claire Larroche, Véronique Le Guern, Jacques Morel, Aleth Perdriger, Carinne Salliot, Stephanie Rist, Alain Saraux, Jean Sibilia, Olivier Vittecoq, Gaétane Nocturne, Philippe Ravaud, Raphaèle Seror

Centre de Ressources Biologiques de l’Hôpital Bichat: Sarah Tubiana

Johan G. Brun for contributing to the Norwegian cohort.

Funding Sources

This work was supported by the Innovative Medicines Initiative 2 Joint Undertaking (IMI 2 JU) (NECESSITY grant 806975). The Joint Undertaking received support from the European Union’s Horizon 2020 Research and Innovation Program and from the European Federation of Pharmaceutical Industries and Associations. This work was also supported by R01 AR065953 Beth the NIH, United States. The contents are the sole responsibility of the authors and do not necessarily the official views of the NIH.

JEG received an unrestricted grant from Bristol-Myer-Squibbs to do the transcriptomic analysis of the ASSESS and Norwegian cohorts. JEG received a grant from Geneviève Garnier (Association Française du Syndrome de Gougerot-Sjögren et des syndromes secs).

The ASSESS cohort is promoted by the French Society of Rheumatology and received two research grants from the French Society of Rheumatology.

The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Disclosure of Interests

Renaud FELTEN: None declared, Tao Ye: None declared, Cédric Schleiss: None declared, Benno Schwikowski: None declared, Jean Sibilia: None declared, Fanny Monneaux: None declared, Hélène Dumortier: None declared, Roland Jonsson: None declared, Christopher Lessard: None declared, Wan Fai Ng: None declared, Tsutomu Takeuchi: None declared, Xavier Mariette: None declared, Jacques-Eric Gottenberg Grant/research support from: JEG received an unrestricted grant from Bristol-Myer-Squibbs to do the transcriptomic analysis of the ASSESS and Norwegian cohorts.

POS0096 SJÖGREN’S DISEASE AND SYSTEMIC LUPUS ERYTHEMATOSUS DDX6-CXCR5 RISK INTERVALS REVEAL COMMON SNPS WITH FUNCTIONAL SIGNIFICANCE IN IMMUNE AND SALIVARY GLAND CELLS

Background

Sjögren’s Disease (SjD) and Systemic Lupus Erythematosus (SLE) are autoimmune diseases with several shared characteristics and similar genome-wide significant associations with the DDX6-CXCR5 locus. DDX6 suppresses interferon-stimulated gene expression and CXCR5 regulates T cell functions implicated in autoimmunity.

Objectives

To identify and characterize functional SNPs in the DDX6-CXCR5 interval.

Methods

ImmunoChip data from European populations (3785 SLE cases; 1916 SjD cases; 6893 controls) were imputed and SNP-trait associations tested. Bayesian statistics defined a credible SNP set that was refined using bioinformatic analyses (RegulomeDB, Haploreg, ENCODE, promoter capture Hi-C, eQTLs, etc.). Electrophoretic mobility shift assays (EMSAs) and luciferase expression assays were used to test allele-specific SNP function in EBV-transformed B (EBV B) cells, Daudi B cells, Jurkat T cells, THP1 monocytes, and A253 salivary gland cell lines. Chromatin conformation capture with quantitative PCR (3C-qPCR) was used to assess long-range chromatin interactions.

Results

Fine mapping of the SjD and SLE associations found similar SNP associations. Bioinformatic analyses identified 5 common SNPs with strong evidence of functionality in immune cell types: rs57494551 in an intron of DDX6, and rs4938572, rs4936443, rs7117261, and rs4938573 in the promoter/enhancer region of DDX6 and CXCR5. EMSAs and luciferase experiments showed cell type-specific differences in protein binding and promoter or enhancer activity, respectively, at each SNP. Risk allele of rs57494551 increased enhancer activity in B cells and A253 cells (p<0.001), but decreased promoter activity in T cells and A253 cells (p<0.01). SNP rs4938572 is an eQTL of DDX6 in T cells, and the risk allele significantly increased protein binding, promoter and enhancer activity in T cells (p<0.01). Risk allele of rs4938572 also increased promoter activity in A253 cells (p<0.001), but had no effect on promoter or enhancer activity in B cells. SNP rs4936443 showed no promoter or enhancer activity in immune cells, but the risk allele showed significant promoter and enhancer (p<0.001) activity in A253 cells. SNP rs7117261 showed decreased enhancer activity in EBV B cells, T cells, and A253 cells (p<0.05) and increased promoter activity in A253 cells (p<0.001). SNP rs4938573 showed decreased promoter activity in EBV B cells, T cell and A253 cells (p<0.05), decreased promoter activity in EBV B cells (p<0.05), and increased enhancer activity in A253 cells (p<0.0001). Overall, A253 cells exhibited more allele-specific effects on promoter and enhancer activity across the five SNPs compared to tested immune cells. In addition to DDX6 and CXCR5, rs57494551 and/or rs4938572 are reported eQTLs for several other genes of interest in the local chromatin regulatory network: IL10RA in T cells, TRAPPC4 in salivary gland and activated macrophages, and long non-coding (lnc)RNA AP002954.1 in T cells and whole blood. 3C-qPCR in EBV B and A253 cells showed that the two regulatory regions carrying rs4938572 or rs57494551 interacted with a region upstream of DDX6 that includes AP002954.1. Hi-C data showed looping between AP002954.1 and the regulatory region carrying rs4938572 and rs57494551 in T cells.

Conclusion

SjD and SLE share similar genomic architecture across the DDX6-CXCR5 risk interval with several common SNPs showing immune and salivary gland cell type-specific allelic effects on protein binding and/or enhancer/promoter activity. Extensive bioinformatic analyses suggest that the SNPs likely work within the local chromatin regulatory network to regulate cell type-specific expression of several genes on the interval. Ongoing studies will use 3C-qPCR to assess allele-specific chromatin interactions between the SNPs and these genes in different cells types, and CRISPR to determine how the risk alleles alters expression.

Disclosure of Interests

Mandi M Wiley: None declared, Bhuwan Khatri: None declared, Kandice L Tessneer: None declared, Michelle L Joachims: None declared, Anna M Stolarczyk: None declared, Anna Nagel: None declared, Astrid Rasmussen: None declared, Simon J. Bowman Consultant of: Abbvie, Galapagos, and Novartis in 2020-2021, Lida Radfar: None declared, Roald Omdal: None declared, Marie Wahren-Herlenius: None declared, Blake M Warner: None declared, Torsten Witte: None declared, Roland Jonsson: None declared, Maureen Rischmueller: None declared, Patrick M Gaffney: None declared, Judith A. James: None declared, Lars Ronnblom: None declared, R Hal Scofield: None declared, Xavier Mariette: None declared, Wan Fai Ng: None declared, Kathy Sivils Employee of: current employee of Janssen., Gunnel Nordmark: None declared, Betty Tsao: None declared, Christopher Lessard: None declared

POS0456 AUTOPHAGY-RELATED RISK LOCI IN SLE AND THEIR ROLE IN NEUTROPHILS

Background

Systemic lupus erythematous (SLE) is an autoimmune disease with ~150 established susceptibility risk loci. Genome wide-association (GWA) studies in SLE cases and controls of Korean ancestry identified the SLE risk locus ATG16L2-P2RY2, and rs11235604 as a SLE-associated missense variant (R220W) of Autophagy Related 16 Like 2 (ATG16L2) [1]. PRDM1-ATG5 is also an SLE risk locus in European populations that is implicated in autophagy. Autophagy plays a crucial role in neutrophil extracellular trap (NET) formation, degranulation, and limiting autoantigens in blood. Dysregulated autophagy has been implicated in SLE pathology and poor disease outcomes. The function of ATG16L2 is unknown, but evidence suggests it may function as a negative regulator of autophagosome formation [2].

Objectives

To identify autophagy-related SLE risk variants shared across different ancestry populations and define the role of ATG16L2 in SLE and autophagy.

Methods

SLE case-control GWA scans from European (7568 cases; 1082 controls), African American (4336 cases; 935 controls), Hispanic (3752 cases; 1840 controls), and Korean (1173 cases; 4213 controls) populations were imputed and SNP associations tested. Meta-analysis was performed, then Bayesian statistics were used to define a credible SNP set. Bioinformatic analyses (RegulomeDB, promoter capture Hi-C, eQTLs, etc.) further prioritized SNPs based on predicted functionality. The functional significance of autophagy SLE risk genes, ATG16L1, ATG16L,2 and ATG5, were tested by CRISPR knockout (KO) in PLB-985 cell line. CRISPR-targeted single cell clones were screened for ATG16L1, ATG16L2 or ATG5 deletion using qPCR, NanoPore sequencing, and Western blotting. Changes in autophagy were assessed by Western blotting and confocal microscopy.

Results

Transracial fine-mapping of PRDM1-ATG5 locus identified two SNP associations shared across the credible sets in all populations: rs56886418 (p=1.38x10-5) located in the intron of PRDM1 and rs77791277 (p=1.38x10-5) that tagged a group of SNPs in strong linkage disequilibrium. Cross comparison of the credible SNP sets and bioinformatic analyses of shared SNPs identified rs533733 and rs9373843 as additional likely functional variants. Bioinformatic analyses prioritized rs56886418, an eQTL for ATG5 (p=0.05) and PRDM1 (p=4.75x10-7) in blood cells positioned in a topologically associated domain (TAD) that may interact with ATG5 and PRDM1 promoters in EBV-transformed B cells. SNP rs533733 is an eQTL for ATG5 in neutrophils (p=0.006) and is in a TAD 6.4kb 3’ of PRDM1 that interacts with the ATG5 promoter region where rs9373843 (eQTL of ATG5 in neutrophils (p=0.04)) is positioned. These data suggest that risk SNPs on the PRDM1-ATG5 locus may modulate ATG5 expression and autophagy in specific cell types by modulating the local chromatin regulatory network.

To assess the roles of ATG5, ATG16L1 and ATG16L2 in autophagy, PMA/I-induced hallmarks of autophagy, LC3-I and LC3-II conversion and p62 protein aggregation, were assessed in homozygous and heterozygous ATG5, ATG16L1, or ATG16L2 CRISPR KO PLB-985 cells by Western blotting and confocal microscopy. Loss of ATG5 or ATG16L1 impaired PMA/I-induced autophagosome formation in myeloid-like and differentiated neutrophil-like PLB-985 cells. In contrast, loss of ATG16L2 elevated the conversion of LC3-I to LC3-II and p62 protein aggregation in both cell types, suggesting that ATG16L2 may inhibit autophagy.

Conclusion

Functional characterization of SNPs on the PRDM1-ATG5 and ATG16L2-P2RY2 loci, and the functional characterization of ATG16L2 in myeloid and neutrophil cell lines, provide new insights into the mechanisms that regulate autophagy in health and disease. Ongoing studies will focus on in vitro validation of predicted functional SNPs and will introduce ATG16L2 rs11235604 risk variant in PLB-985 cells to assess its importance in autophagy.

References

[1]Lessard CJ, et al. Arthritis Rheumatol. 2016; 68(5):1197-1209.

[2]Wible DJ, et al. Cell Discov. 2019; 5:42.

Disclosure of Interests

None declared.

OP0111 INTEGRATION OF GWAS AND EPIGENETIC STUDIES IDENTIFIES NOVEL GENES THAT ALTER EXPRESSION IN THE MINOR SALIVARY GLAND IN SJÖGREN’S DISEASE

Background

Sjogren’s disease (SjD) is an autoimmune disease characterized by reduced function of exocrine glands (i.e., salivary and lacrimal glands). Epithelial cell damage resulting from lymphocytic infiltration has been implicated in SjD etiology [1]. How genetic and epigenetic changes influence epithelial-immune cell interactions in SjD pathogenesis remain understudied.

Objectives

Evaluate the role of SjD risk loci in salivary gland tissue to gain insights into the potential genes involved in salivary gland dysfunction.

Methods

SNPs from 16 regions with SNP-SjD associations (P<5x10-8) in our GWAS study (3232 SjD cases) and meta-analysis of ImmunoChip data (619 SjD cases) [2] were interrogated for eQTLs using Genotype-Tissue Expression (GTEx) minor salivary gland data. Subsequent analysis identified genes that were both eQTLs in the minor salivary gland and significantly expressed in RNA-seq and ATAC-seq data from the submaxillary salivary gland epithelial cell line, A253. Pathway enrichment analysis was performed using gProfiler on the genes where coalescence of eQTL, RNA-seq, and ATAC-seq data was observed. To further validate the results, we performed transcriptome-wide association study (TWAS) analysis using GWAS summary statistics and minor salivary gland eQTL GTEx data.

Results

In total, 5884 genome-wide significant SNPs from 16 SjD risk loci were identified as potential minor salivary gland eQTLs using two discovery thresholds: p(FDR)<0.05 provided by eQTL study (3566 SNPs) and p(FDR)>0.05 and p<0.05 in eQTL study (2318 SNPs). Further analysis revealed 10 SjD risk loci with SNPs that were minor salivary gland eQTLs for a total of 155 unique genes that had a coalescence of RNA- and ATAC-seq data in A253 cells. Many SNPs altered the expression of the nearest gene to the risk allele (i.e., index gene), such as IRF5 and TNPO3 on chromosome 7 at 128Mb; however, this locus had 12 additional genes that were eQTLs in minor salivary gland. In contrast, other loci had no reported eQTLs for the index gene, but several reported eQTLs for other genes, such TYK2 on chromosome 19 at 10Mb that showed no change in TYK2 expression but eQTLs for 8 distant genes, including ICAM1. Pathway enrichment analysis revealed an enrichment in Butyrophilin (BTN) family interactions (R-HSA-8851) (PAdj=1.564x10-5), including the BTN2A1, BTN2A2, BTN3A1, BTN3A2 and BTN3A3 gene cluster in the MHC region. In further support, TWAS of the minor salivary gland and the SjD GWAS summary statistics (after Bonferroni correction) showed association between SjD and BTN3A2 (p=1.24x10-42), as well as many other loci in the MHC region. In addition, several long non-coding (lnc) RNAs on chromosome 17 were significant, peaking at RP11-259G18.1 (p=4.43x10-10).

Conclusion

This study shows that SjD-associated risk alleles influence disease by altering gene expression in immune cells and minor salivary glands. Further, our analysis suggests that altered gene expression in the minor salivary gland expands beyond effects on the index gene to several genes on each locus. Interestingly, we observed minor salivary gland eQTLs for several BTN family genes, which act as cell-surface binding partners to regulate cell-cell interactions, including interactions between epithelial cells and activated T cells [3]. Future work will assess chromatin-chromatin-interactions within the 10 SjD risk loci in salivary gland cells and tissues to map local chromatin regulatory networks that regulate gene expression. Additional transcriptional studies of SjD minor salivary gland tissues will provide further insights into how altered gene expression in the salivary gland influences SjD pathology.

References

[1]Verstappen. Nat Rev Rheumatol 2021;17(6):333-348.

[2]Khatri, et al. Annals of Rheumatic Diseases 2020;79:30-31.

[3]Arnett HA, Viney JL. Nature Reviews Immunology 2014;14:559-569.

Disclosure of Interests

Farhang Aghakhanian: None declared, Mandi M Wiley: None declared, Bhuwan Khatri: None declared, Kandice L Tessneer: None declared, Astrid Rasmussen: None declared, Simon J. Bowman Consultant of: Abbvie, Galapagos, and Novartis in 2020-2021., Lida Radfar: None declared, Roald Omdal: None declared, Marie Wahren-Herlenius: None declared, Blake M Warner: None declared, Torsten Witte: None declared, Roland Jonsson: None declared, Maureen Rischmueller: None declared, Patrick M Gaffney: None declared, Judith A. James: None declared, Lars Ronnblom: None declared, R Hal Scofield: None declared, Xavier Mariette: None declared, Marta Alarcon-Riquelme: None declared, Wan Fai Ng: None declared, Kathy Sivils Employee of: Current employee of Janssen, Gunnel Nordmark: None declared, Umesh Deshmukh: None declared, A Darise Farris: None declared, Christopher Lessard: None declared

POS0098 LINC01871, IMPLICATED IN SJÖGREN’S DISEASE PATHOGENESIS, IS REGULATED BY INTERFERON-G AND CALCINEURIN SIGNALING

Background

Sjögren’s disease (SjD) is an autoimmune disease characterized by exocrine gland dysfunction. Long non-coding RNAs (lncRNAs) are a functionally diverse class of non-protein coding RNAs that are longer than 200 nucleotides. Our previous study using whole blood RNA-seq found that lncRNA, LINC01871, is overexpressed in SjD relative to controls [1]. CRISPR-Cas9 targeting in HSB2 T cells yielded a LINC01871-/- clone with altered expression of many genes implicated in immune regulation [1].

Objectives

The goal of this study was to analyze the gene expression perturbations resulting from the loss of LINC01871 and to characterize the regulation of LINC01871 in both the LINC01871-/- clone and primary human T cells in response to immune stimuli.

Methods

Flow cytometry and LegendPlex bead assays were used to compare surface and secreted protein expression changes, respectively, in LINC01871-/- cells and the parental HSB2 cells. Parental HSB2 T cells, LINC01871-/- cells, Kasumi-3 myeloid cells, and primary human T cells were stimulated in vitro and changes in gene expression were measured over time using qRT-PCR. Responses to interferons (IFN) were assessed using universal type I IFN (IFNα) or IFNγ. TCR signaling responses were assessed using PMA/Ionomycin (PMA/I) or anti-CD3/CD28 stimulations in the presence or absence of the calcineurin inhibitor, FK506.

Results

Previous RNA-seq analysis found 1166 differentially expressed (DE) transcripts (log2FC ≥1 or ≤-1; padj ≤0.05) in LINC01871-/- cells compared to parental HSB2 cells, including many prominent immune regulatory genes. Changes in the basal expression of 7 proteins in LINC01871-/- cells were confirmed using flow cytometry (significantly decreased: CD8a (p=0.0004), CD30 (p=0.0008), CXCR3 (p=0.037), T-Bet (p=0.0002), and Aiolos (p=0.02); significantly increased: CD226 (p=0.0059) and CD44 (p=0.024)). Analysis of LINC01871-/- cells revealed a growth inhibition in LINC01871-/- cells (p=0.0014 at 72h), in which multiple secreted growth and adhesion factors were significantly reduced: GM-CSF (p=2.0e-06), M-CSF (p=2.7e-09), IGBPF4 (p=1.2e-07), s-ICAM1 (p=0.015), MMP9 (p=3.0e-14), and MMP2 (p=6e-08). In contrast, the IL-6 cytokine family member, LIF, was significantly increased in LINC01871-/- cells (p=1.2e-07). Because HSB2 cells were not responsive to all IFNs, IFN-mediated regulation of LINC01871 expression was examined in the Kasumi-3 myeloid cell line. While LINC01871 expression was not modulated by type I IFN stimulation, it was robustly responsive to IFNγ treatment. Since LINC01871 was expressed in T cells and implicated in T cell pathways, responses to TCR signaling pathways were characterized in HSB2 cells or purified primary human T cells treated with PMA/I. In both cell types, LINC01871 exhibited a prolonged decrease in expression that was abrogated by concurrent treatment with FK506, indicating that LINC01871 is regulated by calcineurin signaling. Treatment of primary human T cells with anti-CD3/CD28 to mimic true TCR engagement resulted in a modest decrease of LINC01871 expression at early time points, followed by an increase in expression with longer stimulation (2d).

Conclusion

Our findings suggest that LINC01871 is a potential mediator of the dysregulated T cell inflammatory response pathways implicated in SjD pathogenesis. LINC01871 influences the expression of many important immune cell genes and growth factors, is inducible by IFNγ, and is regulated directly by calcineurin signaling and TCR ligand engagement. Although LINC01871 functions are still unknown, observed LINC01871 overexpression in whole blood of SjD cases and after prolonged TCR stimulation in primary human T cells suggests that it could be a biomarker of SjD.

References

[1]Joachims, et al. Annals of the Rheumatic Diseases 2020;79:90.

Disclosure of Interests

Michelle L Joachims: None declared, Bhuwan Khatri: None declared, Chuang Li: None declared, Kandice L Tessneer: None declared, John Ice: None declared, Anna M Stolarczyk: None declared, Nicolas Means: None declared, Kiely Grundahl: None declared, Stuart Glenn: None declared, Jennifer Kelly: None declared, David Lewis: None declared, Lida Radfar: None declared, Donald Stone: None declared, Joel Guthridge: None declared, Judith A. James: None declared, R Hal Scofield: None declared, Graham B Wiley: None declared, Jonathan Wren: None declared, Patrick M Gaffney: None declared, Courtney Montgomery: None declared, Kathy Sivils Employee of: Current employee of Janssen., Astrid Rasmussen: None declared, A Darise Farris: None declared, Indra Adrianto: None declared, Christopher Lessard: None declared

AB0026 CELL TYPE-SPECIFIC DYSREGULATION FOUND TO DIFFERENTIATE PATIENT SUBSETS OF SJÖGREN’S DISEASE

Background

Sjögren’s disease (SjD) is a chronic, heterogenous autoimmune disorder characterized by inflammatory destruction of the exocrine glands and Ro autoantibodies. Previous studies, most in whole blood, reported transcriptional and cell type differences between SjD subphenotypes.

Objectives

Evaluate the role of cell type-specific dysregulation in subpopulations of SjD patients having focal lymphocytic sialadenitis and/or anti-Ro/SSA and/or ANA positivity using single-cell RNA-seq (scRNA-seq).

Methods

Peripherical blood mononuclear cells (PBMCs) stored at -120°C from 30 SjD patients and 10 healthy controls (HCs) were selected from our OMRF Sjögren’s Research Cohort based on ACR/EULAR 2016 criteria. PBMCs were captured, libraries processed using 10X Genomics Chromium v3.1 and sequenced to a depth of ~45,000 reads/cell. 10X Genomics Cell Ranger (v 6.1.2) cell multiplexing pipeline was used to align reads to the GRCh38 human genome and separate combined data to per-sample output files. Seurat R package was used for quality control (QC), integration, clustering, and cell type assignment. Differential expression (DE) analysis was done using Seurat for genes with 10% or more of the cells showing expression. DE transcripts (defined as padj<0.05) were evaluated using Ingenuity Pathway Analysis (IPA).

Results

After removing cells with low feature counts, high mitochondrial gene counts, and/or other QC criteria, a total of 331,981 cells were captured. Cells were mapped to 28 clusters using Seurat, then cell types were predicted using marker genes developed from an in-house reference panel of publicly available scRNA-seq datasets. Mapping condensed the 28 observed cell clusters to 19 clusters of specific cell types; 4 clusters remained unidentified. Percentages of each cell type were compared across various subsets of SjD (Ro+; Ro-; Ro-/ANA+; Ro-/ANA-) and HCs. CD14 monocytes were decreased in Ro-/ANA- vs. Ro+ or Ro-/ANA+ cases (p<0.05) and trended downward when compared to HCs (p=0.057). CD8 central memory T cells (TCM) were decreased in Ro+ vs. Ro- or Ro-/ANA- cases (p<0.02) and trended downward when vs. HCs (p=0.076). Conventional dendric cells (DCs) were increased in Ro+ vs. Ro-/ANA- SjD cases (p=0.036) and trended upward in Ro+ vs. Ro- cases (p=0.08) but were not significantly different from HCs. Natural killer (NK) cells were increased in both Ro-/ANA- and Ro- vs. Ro+ (p<0.05).

DE analysis between immune cell subsets revealed potential subphenotype-specific differences in pathophysiology. Interferon signaling was upregulated in CD14 monocytes, naïve B, and CD4 central memory (TCM) cells from the Ro+ subset. Ro+ subset also showed upregulation of genes involved in T cell receptor signaling in CD4 cytotoxic T (CTL), CD4 TCM, and CD4 effector memory T (TEM) cells, but downregulation of this pathway in CD8 TCM cells. Ro+ subset also exhibited increased B cell receptor signaling pathway in naïve and memory B cells. Ro+ subset showed downregulation of autophagy in naïve B, CD4 CTL, CD4 TCM, and CD4 TEM cells. Several cell types in Ro+ and Ro-(ANA+/-) subsets showed decreased DE of genes involved in nitric oxide production and NRF2 oxidative stress pathways. Ro- (ANA+/-) vs. HCs showed increased IL6 and TREM1 signaling pathways in CD14 and CD16 monocytes. While Ro+ subsets showed upregulation of B and T cell pathways (shown previously in lupus), Ro- (ANA+/-) showed dysregulation of osteoarthritis and neuroinflammatory pathways. Interestingly, among the DE long intergenic non-coding (linc)RNAs found herein, we observed that LINC01871, which we previously reported as DE in all subsets of SjD, was overexpressed in CD4 CTL and NK cells in both Ro+ and Ro- (ANA-) vs. HCs.

Conclusion

This interim analysis shows similarities and differences in the dysregulation of genes and pathways for specific cell subsets from our Ro+ and Ro- (ANA+/-) subsets of SjD, potentially allowing for more tailored diagnostics and interventions for the disease in the future.

Disclosure of Interests

Chuang Li: None declared, Bhuwan Khatri: None declared, Anna M Stolarczyk: None declared, Kandice L Tessneer: None declared, Astrid Rasmussen: None declared, Joel Guthridge: None declared, Judith A. James: None declared, R Hal Scofield: None declared, He Li Employee of: Current employee of Janssen, A Darise Farris Grant/research support from: Active collaborative research agreement with Janssen, Kathy Sivils Employee of: Current employee of Janssen, Christopher Lessard Grant/research support from: Active collaborative research agreement with Janssen

OP0140 DYSREGULATED EXPRESSION OF THE LONG NON-CODING RNA, LINC01871, IMPLICATED IN SJÖGREN’S SYNDROME PATHOGENESIS

Background:

Sjögren’s syndrome (SS) is a chronic, heterogenous autoimmune disease characterized by inflammatory destruction of the exocrine glands. Long non-coding RNAs (lncRNAs) have emerged as a functionally diverse class of non-protein coding RNA (ncRNA) with increasing implications in interferon signaling, immune cell regulation, and autoimmune disease pathology. The potential role of lncRNAs in SS pathogenesis is unknown.

Objectives:

To identify and characterize candidate lncRNAs with potential relevance to SS pathology.

Methods:

RNA-seq was used on whole blood from SS patients (n=30 antibody negative (Ro-); n=27 antibody positive (Ro+)) and healthy controls (HC, n=27) to identify differentially expressed (DE) lncRNAs (log2 fold change (FC) ≥ 2 or ≤ 0.5; padj<0.05). Bioinformatic and pathway analyses were used to predict lncRNA function.In vitrotime course experiments in HSB2 T cell lymphoblasts stimulated with PMA/Ionomycin (PMA/I) or type I interferon (IFN) were used to assess biological relevance.LINC01871function was further investigated by RNA-seq on a single cell clone of HSB2 with confirmed CRISPR-targetedLINC01871deletion (LINC01871-/-).

Results:

We identified a total of 1054 unique DE ncRNAs between Ro+, Ro-and/or a combined analysis relative to HC; of these, 45 (1 long intergenic ncRNA (lincRNA), 1 antisense, 43 pseudogenes) were overexpressed in all 3 SS subsets. To begin investigating the function of the previously undescribed lincRNA,LINC01871(SSRo-: FC=2.85; padj=1.1x10-4), we performed a correlation analysis of the SSRo-transcriptome, which found several co-expressed protein coding RNAs involved in immune regulation (THEMIS,TBX21,IL10RA,IL2RB,among many others). Similarly, Ingenuity Pathway Analysis of the SS transcriptome compared to HC, as well as several gene ontology enrichment analyses of publicly available RNA expression correlation databases, identified shared immune-related pathways including cytotoxic T cell, natural killer cell, and T cell regulation. To further study the role ofLINC01871in cytotoxic T cells, we used qRT-PCR to resolve the effects of PMA/I or type I IFN stimulation onLINC01871expression in the T lymphoblastoid HSB2 cells.LINC01871expression was downregulated after PMA/I stimulation, but unchanged with type I IFN stimulation. To explore the regulatory function ofLINC01871in T cells, we targetedLINC01871in HSB2 cells using CRISPR. To this end, we generated a single cellLINC01871-/-clone with no RNA expression by qPCR and confirmed homozygous deletion using DNA sequencing. RNA-seq analysis ofLINC01871-/-compared to unmodified HSB2 cells identified 1166 DE transcripts. Pathway analyses clustered the DE transcripts into similar immune regulatory, cytotoxic and T cell pathways identified in SSRo-whole blood RNA-seq and publicly available RNA-seq databases. Further, several prominent T cell regulatory transcripts that exhibited correlated upregulation withLINC01871in SSRo-whole blood RNA-seq also demonstrated downregulation afterLINC01871deletion:CD109(FC=-9.7; padj=5.3x10-16),IL22(FC=-8.1; padj=7.6x10-11),PDCD1(FC=-6.2; padj=1.1x10-6),THEMIS(FC=-3.8; padj=2.7x10-165) andTBX21(FC=-2.1; padj=3.3x10-25).

Conclusion:

LncRNAs are emerging as important regulators of immune function with increasing evidence of autoimmune disease relevance. Here, we leveraged RNA-seq, extensive bioinformatic data, and CRISPR technology to identify and functionally characterizeLINC01871as a potential mediator of the dysregulated T cell inflammatory response pathways implicated in SS pathogenesis.

Disclosure of Interests:

Michelle L Joachims: None declared, Bhuwan Khatri: None declared, Kandice L Tessneer: None declared, Anna M Stolarczyk: None declared, Graham B Wiley: None declared, Astrid Rasmussen Speakers bureau: Novartis, ThermoFischer, Joel Guthridge Grant/research support from: Xencor, Bristol Myers Squibb, DXterity, Judith A. James Grant/research support from: Progentec Diagnostics, Inc, Consultant of: Abbvie, Novartis, Jannsen, R Hal Scofield Grant/research support from: Pfizer, Kathy L Sivils: None declared, Indra Adrianto: None declared, Christopher Lessard: None declared

OP0139 FUNCTIONAL EVALUATION OF THE SJÖGREN’S SYNDROME AND SYSTEMIC LUPUS ERYTHEMATOSUS DDX6-CXCR5 RISK INTERVAL

Background:

Sjögren’s Syndrome (SS) and Systemic Lupus Erythematosus (SLE) are distinct chronic, complex autoimmune diseases with shared characteristics such as autoantibodies, heightened interferons, and polyarthritis. SS and SLE genome-wide association studies (GWAS) report strong associations with theDDX6-CXCR5risk interval. DDX6 suppresses interferon stimulated gene expression and CXCR5 regulates T cell functions implicated in autoimmunity.

Objectives:

To identify functional variants that impact regulation in theDDX6-CXCR5interval.

Methods:

Fine-mapping was done using ImmunoChip data from 3785 SLE, 1916 SS cases and 6893 population controls of European ancestry that were imputed and tested for SNP-trait association. Bayesian statistics assigned posterior probabilities to SNPs and defined a credible set of risk variants. Bioinformatic analyses further prioritized variants with predicted functionality. Electrophoretic mobility shift assays (EMSAs) and luciferase expression were used to validate predicted SNPs in EBV transformed B (EBV B) cells.

Results:

While some differences were observed, the overall SS and SLE association signals were similar. SNP-SS rs9736016 nearCXCR5and SNP-SLE rs76409436 nearDDX6were the most significant but did not show evidence of functionality. Bayesian statistics defined credible sets of variants in strong D’ in common between both SS and SLE. Bioinformatics analyses (Haploreg, RegulomeDB, ENCODE data, etc) further refined the credible set and identified 5 common SNPs with strong evidence of functionality in immune cell types: rs4938572, rs4936443, rs57494551, rs7117261 and rs4938573. EMSAs showed a significant increase in protein binding to the risk allele of rs57494551 (p=0.0001), rs7117261 (p=0.0001) and rs4938573 (p=0.0003), but not the others, using nuclear lysates from EBV B cells. Luciferase vectors with a minimal promoter or no promoter were used to test for enhancer or promoter activity, respectively. To this end, the rs57494551 risk allele exhibited a significant increase in enhancer activity (p=0.0001). In contrast, the rs7117261 risk allele decreased enhancer activity (p=0.018). The rs4938573 risk allele decreased enhancer (p=0.043) and promoter (p=0.024) activity. While rs7117261 or rs4938573 were not reported in eQTL databases, GTex data reported rs57494551 as an eQTL that altersDDX6expression in whole blood (p=1.8E-7). Additionally, these functional SNPs have been associated with looping events to several proximal promoters in nearby genes in immune cells.

Conclusion:

SS and SLE have similar genomic architecture across theDDX6-CXCR5risk interval. Multiple variants in the credible set exhibited allele specific changes in protein binding, as well as modified enhancer activity, promoter activity or both. Ongoing studies will use Cas9 in EBV B cells to determine which other loci are within the local regulatory network.

Disclosure of Interests:

Mandi M Wiley: None declared, Bhuwan Khatri: None declared, Kandice L Tessneer: None declared, Michelle L Joachims: None declared, Anna M Stolarczyk: None declared, Astrid Rasmussen Speakers bureau: Novartis, ThermoFischer, Simon J. Bowman Consultant of: Astrazeneca, Biogen, BMS, Celgene, Medimmune, MTPharma, Novartis, Ono, UCB, xtlbio, Glapagos, Speakers bureau: Novartis, Lida Radfar: None declared, Roald Omdal: None declared, Marie Wahren-Herlenius: None declared, Blake M Warner: None declared, Torsten Witte: None declared, Roland Jonsson: None declared, Maureen Rischmueller: None declared, Patrick M Gaffney: None declared, Judith A. James Grant/research support from: Progentec Diagnostics, Inc, Consultant of: Abbvie, Novartis, Jannsen, Lars Ronnblom Grant/research support from: AZ, Speakers bureau: AZ, R Hal Scofield Grant/research support from: Pfizer, Xavier Mariette: None declared, Wan-fai Ng: None declared, Kathy L Sivils: None declared, Gunnel Nordmark: None declared, Betty Tsao: None declared, Christopher Lessard: None declared

OP0047 GENOME-WIDE ASSOCIATION STUDY OF SJÖGREN’S SYNDROME IDENTIFIES TEN NEW RISK LOCI

Background:

Sjögren’s syndrome (SS) is a complex autoimmune disease with exocrine gland dysfunction leading to substantial morbidity. There are 10 published genetic susceptibility loci.

Objectives:

Our genome-wide association study (GWAS) aimed to identify additional risk loci of genome-wide significance (GWS; p<5E-08) in European-derived primary SS.

Methods:

A total of 3232 cases and 17481 controls genotyped on GWAS arrays and 619 cases and 6171 controls genotyped on ImmunoChip (IC) arrays were imputed after quality control. Logistic regression was calculated adjusting for ancestry using the first 4 principal components to identify SS-associated SNPs. GWAS and IC results were meta-analyzed using weighted Z-scores. Bayesian statistics were used to assign posterior probabilities and define credible SNP sets for each locus. Bioinformatic analyses were used to predict functionality.

Results:

Seven novel loci exceeded GWS in the GWAS analysis:NAB1,MIR146A-PTTG1,XKR6,MAPT-CRHR1,RPTOR-CHMP6-BAIAP2,TYK2andSYNGR1. Meta-analysis with IC data identified three more novel loci exceeding GWS:CD247,PRDM1-ATG5andTNFAIP3. Several additional loci with suggestive association (p<1E-05) were also identified:ADAMTSL2,CGNL1andPHRF1.

Several identified loci have reported functional implications in immune regulation and autoimmune disease. In lupus, rs2431697 correlated with rs2431098, which was shown to alterMIR146Aexpression, resulting in type I interferon pathway imbalance. Similarly,TYK2risk association reportedly drives interferon, IL10 and RET signaling pathways.PRDM1encodes Blimp-1, a master regulator of immune cell differentiation.CD247encodes the zeta subunit of the T cell receptor complex.XKR6is implicated in apoptotic cell ingestion.ATG5is also involved in apoptosis, as well as autophagy and antigen presentation.

Additional bioinformatics analyses (Haploreg, Regulome DB, ENCODE, etc.) revealed immune-relevant functional implications for each risk locus. The SS-associated credible set included variants downstream ofTNFAIP3in a region reported to abolish looping between an enhancer and theTNFAIP3promoter in lupus and a coding variant that has been shown to alter NF-kB activity and neutrophil extra-cellular traps. The rs2293765 in the 5’ UTR ofNAB1showed evidence of enhancer/promoter activities. The rs2069235 in theSYNGR1locus showed enhancer and transcription start site activities in B and T cells. The rs7210219 in theMAPT-CRHR1locus showed enhancer/promotor activities in various tissues.

Conclusion:

We have identified ten novel genetic susceptibility loci associated with SS pathology. Our finding increases the current number of GWS regions in SS patients of European origin, from 10 to 20. Future work is needed to identify and characterize the functional variants in each region.

Disclosure of Interests:

Bhuwan Khatri: None declared, Tove Ragna Reksten: None declared, Kandice L Tessneer: None declared, Astrid Rasmussen Speakers bureau: Novartis, ThermoFischer, R Hal Scofield Grant/research support from: Pfizer, Simon J. Bowman Consultant of: Astrazeneca, Biogen, BMS, Celgene, Medimmune, MTPharma, Novartis, Ono, UCB, xtlbio, Glapagos, Speakers bureau: Novartis, Joel Guthridge Grant/research support from: Xencor, Bristol Myers Squibb, DXterity, Judith A. James Grant/research support from: Progentec Diagnostics, Inc, Consultant of: Abbvie, Novartis, Jannsen, Lars Ronnblom Grant/research support from: AZ, Speakers bureau: AZ, Blake M Warner: None declared, Xavier Mariette: None declared, Roald Omdal: None declared, Javier Martin Ibanez: None declared, Maria Teruel: None declared, Janicke Liaaen Jensen: None declared, Lara A Aqrawi: None declared, Øyvind Palm: None declared, Marie Wahren-Herlenius: None declared, Torsten Witte: None declared, Roland Jonsson: None declared, Maureen Rischmueller: None declared, A Darise Farris Speakers bureau: Biogen, Marta Alarcon-Riquelme: None declared, Wan-fai Ng: None declared, Kathy L Sivils: None declared, Gunnel Nordmark: None declared, Christopher Lessard: None declared

Effect of superstimulation protocols on nuclear maturation and distribution of lipid droplets in bovine oocytes

Our objective was to study the effect of superstimulation protocols on nuclear maturation of the oocyte and the distribution of lipid droplets in the ooplasm. Heifers (n = 4 each group) during the luteal phase were either treated with FSH for 4 days (Short FSH), FSH for 4 days followed by 84 h of gonadotropin free period (FSH Starvation) or for 7 days (Long FSH) starting from the day of wave emergence. In all groups, LH was given 24 h after induced luteolysis (penultimate day of FSH) and cumulus–oocyte complexes were collected 24 h later. Oocytes were stained for nuclear maturation (Lamin/chromatin) and lipid droplets (Nile red). The Long FSH group had a greater proportion of mature oocytes (metaphase II) compared with heifers in the Short FSH and FSH Starvation groups (59/100 vs 5/23 and 2/25, respectively; P < 0.01). On average across all groups, oocytes contained 22 pL of lipids (3.3% of ooplasm volume) distributed as 3000 droplets. Average volume of individual lipid droplets was higher in the FSH Starvation (11.5 ± 1.5 10–3 pL, P = 0.03) compared with the Short and Long FSH groups (7.2 ± 0.6 10–3 and 8.0 ± 0.8 10–3 pL, respectively). In conclusion, both FSH Starvation and Short FSH treatments yielded a lower proportion of mature oocytes compared with the Long FSH treatment. Furthermore, FSH starvation led to an accumulation of larger lipid droplets in the ooplasm, indicating atresia. Our results indicate that a longer superstimulation period in beef cattle yields higher numbers and better-quality oocytes.

Effects of pipothiazine palmitate on handling stress and on the characteristics of semen collected by electroejaculation in bison (Bison bison) bulls

Handling North American bison can pose risk to the handler and evoke stress in the animal. Moreover, this induced stress might affect qualities of semen collected by electroejaculation. The objective of this study was to investigate if a long acting neuroleptic tranquilizer (LAN) would reduce the stress of bison and thereby improve the quality of electroejaculated semen. Eight experimental replicates were conducted between May and November. In each replicate, the same six bison bulls were randomly assigned into LAN-treated (n=3) and non-treated control (n=3) groups. Pipothiazine palmitate (Piportil L4) was administered intramuscularly as a single dose of 100 mg in replicates 1-4 or 200 mg in replicates 5-8. Within each replicate, semen was collected by electroejaculation at 4, 6, 11 and 13 days post treatment. Behavioral parameters, sperm morphology and motility parameters were analyzed. A blood sample was collected before each electroejaculation and serum concentrations of testosterone, cortisol and corticosterone were determined. Treatment bulls with 100 mg of Piportil L4 reduced the restraint time and the struggling of bison bulls during handling compared to the control group (P<0.05). Semen motility parameters and serum concentrations of testosterone, cortisol and corticosterone were not significantly affected when 100mg of the LAN was administered (P>0.05). However, giving 200 mg of Piportil L4 reduced the restraint time of bison bulls and the duration of semen collection (P<0.05). Also, this treatment improved total and progressive sperm motilities when compared to the respective controls (P<0.05). Interestingly, serum concentration of corticosterone, as an endocrine stress indicator, was decreased after administration of 200mg of Pipothiazine palmitate, while testosterone concentrations were increased compared to those values in untreated control bulls (corticosterone: 0.10±0.01 compared with 0.15±0.02 ng/mL; testosterone: 9.11±1.68 compared with 5.33±0.74 ng/mL; P<0.05). In conclusion, this study demonstrated that a treatment dose of 200mg of Piportil L4 can decrease the behavioral and endocrine stress responses in bison bulls, which indirectly increasing testosterone concentrations and improving semen quality.

242 EFFECTS OF TWO COMMERCIAL BOVINE SEMEN EXTENDERS FOR SHORT-TERM STORAGE ON MOTILITY PATTERN OF CHILLED BISON SEMEN

Difficulties of adequate cryopreservation of bison semen has limited the success of artificial insemination and in-vitro embryo production in bison. We evaluated the effects of short-term cooling on motility of bison sperm using two commercial semen extenders (Triladyl® and Andromed®; Minitube, Ingersoll, ON, Canada). Semen was collected by electroejaculation of mature wood bison (n = 3) and plains bison (n = 3) twice a week for 2 wk. Upon collection, the ejaculate was divided into 3 equal aliquots, which were then diluted 1:2 (vol/vol) in Triladyl or Andromed, or were not extended (n = 24 samples per treatment). Samples were maintained at 37°C until transfer to the laboratory (≤2 h). One millilitre of each sample was then placed into a test tube (15 mL, BD Falcon, BD Biosciences, San Jose, CA, USA) and were kept in water bath set at 5°C inside a walk-in refrigerator (4°C). Characteristics of sperm motility were evaluated before cooling (Day 0) and every 24 h after cooling for 5 days using a computer-assisted semen analyzer. Total motility (TM), progressive motility (PM), velocity curved line (VCL), velocity average path (VAP), and velocity straight line (VSL) were compared among treatments by ANOVA for repeated-measures. Values are expressed as mean ± SEM. After collection, the PM of the raw semen and semen extended in Triladyl or Andromed were not significantly different (63.1 ± 4.4%, 63.3 ± 3.1%, and 56.9 ± 4.5%, respectively). Cooling semen for a period of 24 h resulted in a decrease (P < 0.05) in PM in all 3 groups (4.4 ± 2.0%, 22.7 ± 2.9%, and 28.7 ± 4.3%, respectively). The PM of semen extended in Tryladyl or Andromed was greater than that of raw semen on Day 1 (P < 0.05). Semen extended in Triladyl and Andromed maintained PM on Day 2 (24.7 ± 3.3% and 21.8 ± 3.8%, respectively), but PM declined progressively to 1.1 ± 0.6% and 6.3 ± 2.1% by Day 5. A similar pattern was observed for the TM. The VCL, VAP, and VSL parameters for semen extended with Triladyl and Andromed decreased gradually between Day 0 and Day 5 (P < 0.05). From Day 1 to 4 after cooling, these velocity parameters were not significantly different between semen extended with Triladyl or Andromed; however, they were greater than those of raw semen (P < 0.05). All sperm velocity parameters for the raw semen declined by more than 60% between Days 0 and 2 (P < 0.05). On Day 0, VCL for semen extended with Andromed (152.2 ± 4.3) was greater than that of semen extended with Triladyl and raw semen (P < 0.05; 122.5 ± 7.0 and 122.4 ± 6.6, respectively). The VCL then decreased to 98.9 ± 12.9, 100.5 ± 10.8, and 18.6 ± 6.8 in Andromed, Triladyl and raw groups respectively on Day 2 (P < 0.05), followed by a further decline to 51.8 ± 14.3, 19.9 ± 10.0, and 9.0 ± 5.0, respectively, observed on Day 5. In conclusion, both Triladyl and Andromed improved characteristics of sperm motility of chilled bison semen. Despite an initial decrease within the first 24 h, bison sperm extended with Triladyl or Andromed maintained an acceptable degree of motility for up to 2 days after chilling to 5°C. Supported by Agriculture and Agri-Food Canada, Agriculture and Development Fund, and Canadian Animal Genetic Resources program.

233 EFFECTS OF A LONG-ACTING TRANQUILIZER ON SPERM MOTILITY OF NORTH AMERICAN BISON BULLS

Handling induces stress in North American bison that can lead to injuries for both handlers and animals. Moreover, this induced stress may result in variations in collection and quality of the semen. The objective of this study was to investigate if a long-acting neuroleptic (LAN) can lower the stress on bison bulls, allowing for safer handling and improvement in the quantity and quality of the collected semen. For this study, 6 mature bison bulls (3 Bison bison bison and 3 Bison bison athabascae) housed at the Native Hoofstock Centre, near Saskatoon, SK, Canada, were used. For each trial, bison bulls were randomly separated into 2 groups: LAN-treated (n = 3) and nontreated control (n = 3). In the treatment group, each bull was injected with 100 mg of Piportil L4® (piperodine phenothiazine, a LAN with antipsychotic properties and weak sedative activity that has a prolonged duration of action ≈2 wk). After injection, both groups were given a 5-day rest period before semen collection. All bison were collected by electroejaculation, twice a week for 2 wk with a minimum 48 h of rest between collections (total of 3 trials; 4 collections per trial). Between each trial, a rest period of 1 wk was given to the bulls. To evaluate the stress level of the animal, the bull’s heart and respiration rates were recorded before and after each collection. Electroejaculated semen was kept at 37°C and transported to the laboratory for further semen analysis (≈2 h). Semen was analysed using computer assisted sperm analyzer. Several parameters including volume, concentration, total motility, progressive motility, velocity curvilinear (VCL), velocity average path (VAP), and velocity straight line (VSL) were recorded. The data were analysed using two-way ANOVA (SAS 9.2; SAS Institute, inc., Cary, NC, USA). Data are presented as mean ± SD and P < 0.05 level of significance. Results for the stress level revealed that the heart rate (beats/min) before semen collection (control: 65.8 ± 14.6, treated: 65.3 ± 9.4) and heart rate after semen collection (control: 67. 9 ± 14.4, treated: 62.9 ± 9.1) showed no differences between control and treatment. Both respiration rates (breaths/min) before and after collection did not show difference due to treatment (control: 44.1 ± 17.5 and 36.6 ± 15.1, and treated: 41.6 ± 22.0 and 35.3 ± 14.3, respectively). Results of the semen analysis showed no significant effect of treatment on the volume of ejaculate between control (5.3 ± 2.0 mL) and treated (4.6 ± 2.4 mL). Both total and progressive motility of the semen showed no difference between control (70.5 ± 18.1% and 64.6 ± 19.4%) and treated (64.6 ± 22.7% and 58.6 ± 23.2%), respectively. No significant effects were seen in any of the sperm velocity parameters (μm s–1): VCL, 123.5 ± 31.5 in control and 121.7 ± 28.9 in treated; VAP, 75.4 ± 18.7 in control and 71.8 ± 17.2 in treated; and VSL, 62.3 ± 16.9 in control, and 59.3 ± 15.3 in treated groups. It can be concluded that 100 mg of Piportil has no discernible effect on stress levels, sperm count, or motility in bison bulls. Funded by Agriculture Development Fund (#2008044) and Canadian Animal Genetic Resources program.

306 THE EFFECT OF BoviPURE GRADIENT ON BISON SPERM CRYOPRESERVATION

Endemic tuberculosis and brucellosis threaten Canada’s wood bison population. For the purposes of developing a procedure to harvest pathogen-free sperm from bison, a sperm separation and purification product, BoviPure, was tested to determine its effect on bison sperm viability before and after cryopreservation. BoviPure (NidaCon International AB, Mölndal, Sweden) is a density centrifugation gradient system that contains trypsin and is designed to separate motile from non-motile sperm and remove infectious pathogens. Spermatozoa were expelled from the caudal epididymis of bison testicles collected at slaughter and diluted in 3 to 5 mL of TCM-199 medium (Gibco, Burlington, Ontario, Canada). After 1 h of incubation at 37°C, 1 to 1.5 mL of diluted sample (approximately 300 × 106 sperm) was placed in (1) a BoviPure gradient containing trypsin (n = 18 samples), (2) a BoviPure gradient without trypsin (n = 10 samples), or 3) left untreated (control; n = 20). Gradients were centrifuged at 300g for 20 min. The sperm pellet was resuspended in 5 mL of TCM-199 medium and recentrifuged at 500 g for 10 min. Total and progressive motility were estimated using computer-assisted sperm analysis (CASA). Gradient-treated and untreated sperm samples were diluted in an egg yolk extender (Triladyl; Minitube Canada, Ingersoll, Ontario, Canada), placed in 0.5-mL straws (50-200 × 106 spermatozoa per straw), frozen, and stored in liquid nitrogen for a minimum of 24 h. Semen straws were thawed by plunging in a 37°C water bath for 30 s, and motility measurements were taken immediately by CASA. Total and progressive motility were compared among groups by analysis of variance. Before cryopreservation, total motility and progressive motility were not affected by gradient processing. Total motility was 85±5.1%, 80±4.8%, and 77 ± 3.7% for untreated, BoviPure with trypsin, and BoviPure without trypsin, respectively (mean ± SEM), and progressive motility was 74 ± 2.7%, 77 ± 3.8%, and 68 ± 4.7%, respectively. After freezing and thawing, total motility decreased compared to unfrozen samples (P < 0.0001) but was not different among groups (37 ± 3.6%, 33 ± 3.7%, and 29 ± 4.8% for untreated, BoviPure with trypsin, and BoviPure without trypsin, respectively). Similarly, progressive motility decreased compared to unfrozen samples (P < 0.0001) but was not different among groups (26 ± 3.6%, 21 ± 3.7%, and 14.5 ± 4.9% for untreated, BoviPure with trypsin, and BoviPure without trypsin, respectively). We conclude that the BoviPure gradient with or without trypsin does not influence total motility or progressive motility of bison sperm either before or after cryopreservation and has potential as a method of harvesting pathogen-free sperm from wild animals of unknown disease status. This study was supported by Canadian Adaptation and Rural Development in Saskatchewan.

350 EFFECT OF PROGESTERONE SUPPLEMENTATION OF MATURATION MEDIUM ON DEVELOPMENT OF IVM-IVF-IVC BOVINE EMBRYOS

Follicular fluid from small and large bovine follicles contains large amounts of progesterone, and during preovulatory period progesterone concen- tration increase markedly by 18 h after LH surge. Furthermore, cumulus cells express membrane progestin receptor beta (Liu et al. 2008 Steroids 73, 1416-1423). For these reasons, we hypothesized that progesterone supports maturation of preovulatory bovine oocytes to MII stage. The object of this study was to investigate the effect of progesterone supplementation of in vitro maturation medium on competence of bovine oocyte to develop into blas- tocysts in vitro. COCs were collected by the aspiration of 2-6 mm follicles from ovaries within 6 h of slaughter. The COCs were divided into 5 groups: (1) a control group, TCM-199 supplemented with 5% calf serum (CS) as IVM medium, and (2 to 5) progesterone (P4) supplementation groups, TCM- 199 supplemented with 5% CS and 1, 3, 5, and 10 μg mL-1 of P4. Groups of 10 COCs were incubated in 50-μL drops of IVM media at 38.5°C under an atmosphere of 5% CO2 in air for 20 h. The matured COCs were inseminated with 3 × 106 sperm mL-1. After 18 h of gamete co-culture, the pre- sumptive zygotes were cultured in CR1aa media supplemented with 5% CS for 9 days at 38.5°C under an atmosphere of 5% CO2, 5%O2, and 90% N2. Embryonic development was evaluated at 48 h after IVF (total cleavage rates) and on Days 7 to 9 (blastocyst rate). Data was analyzedby chi-square test. The results are presented in Table 1. There were no significant differences in the cleavage rates between treatments. However, the blastocyst formation rate of 5 μg mL-1 P4 supplementation group was significantly higher than that of 10 μg mL-1 P4 supplementation group (P < 0.05). In addition, the blastocyst formation rates of 10 μg mL-1 P4 supplementation group was lower than the other groups. These results suggest that progesterone supple- mentation of in vitro, maturation medium affects the competence of the oocytes to develop into blastocysts in vitro, and 5 μg mL-1 P4 supplementation may be effective in increasing embryo production. Furthermore, 10 μg mL-1 P4 supplementation has negative effect on the oocyte competence. Table 1.Effect of progesterone supplementation on development of IVF bovine embryos

Exoskeleton Solutions to Bone and Muscle Atrophy Within Microgravity Environments

Weakening of muscle and bone tissue after merely a week of exposure to a microgravity environment has been demonstrated to adversely affect the physiological health of astronauts . Innovative solutions meant to replace traditionally bulky resistance-based devices are highly sought by burgeoning private space travel companies as well as other ambitious spaceflight programs that require a robust and effective solution for long durations in microgravity . The purpose of this study is to explore the unique contributions of exoskeleton technology in providing an effective, compact and elegant preventative device through assessing the current ability of exoskeleton technologies in stressing the body, formulating design requirements of an exoskeleton device and highlighting the areas of exoskeleton development that require further work in the realization of a robust microgravity-atrophy solution. An understanding of the abilities and shortcomings of current exoskeleton technologies is necessary to develop and streamline advanced forms of today's space physiological devices . The physiologically familiar structure of an exoskeleton, being built around the human form, would also provide for a greater degree of compactness, affecting everything from launch expenses to living arrangements in any space module. A more effective and persistent method of stressing the body will ultimately allow for a drastic decrease in bone and muscle atrophy, requiring less therapy should any space traveler return to a gravity environment as well as preventing various related ailments during their time in space. In conducting the study, a literature search was performed to identify fundamental design parameters. Designs were then formulated to best fit the required design specifications with difficult or absent features being noted. Initial design concepts based on traditional resistance-based solutions were also developed to further characterize the particular requirements that an exoskeleton would be required to fulfill. These design concepts were then steadily revised into a potential force generation mechanism and device architecture based on factors including human comfort, force generation, effective ranges of motion, materials and geometry. An appraisal of current exoskeleton technology in actualizing the proposed designs and design specifications provides a basis for analysis. The study has uncovered the strong points in exoskeletal designs as well as the major hurdles that, once crossed, will allow exoskeletal technologies to be a viable application in bone and muscle therapies, both in microgravity environments as well as gravity environments. A large hurdle lies in current exoskeleton technologies still utilizing bulky components but past trends have demonstrated a reliable miniaturization in the technology. Particularly important exercises and ranges of motion have been identified and initial designs formulated based on the physiological requirements. The study has demonstrated the need for more efforts in formulating innovative solutions to space-based physiology problems as well as explicitly listing design parameters required for any potential exoskeleton solution.

C8orf13/BLK association with systemic lupus erythematosus across different ethnicities (136.28)

SLE is a complex autoimmune disease with immunological abnormalities that targets B cell functions and development. Previous genome-wide association studies identified C8orf13/BLK as a novel SLE risk factor. BLK (B lymphoid tyrosine kinase) has been shown to have potential effects on B cell develoment. The main objectives of this study are to: 1.) assess this association in independent populations and 2.) determine if BLK risk alleles correlate with alteration in peripheral blood B cell development and protein expression. We genotyped 52 SNPs within the C8orf13/BLK region in European-derived, Asian and African American populations. rs13277113 is associated with SLE in all three populations. A few novel upstream SNPs within the intergenic region demonstrate a stronger association in Asians. Flow cytometry data suggests there is a significant difference in BLK expression and T2 cells B cell numbers between high-risk and non-risk individuals based on the risk haplotype. Our results suggest that the BLK genetic polymorphisms alter immune system development and function to increase the risk for SLE development. Supported by NIH RR020143, RR015577, NIAID-DAIT-BAA-05-11, AI031584, AR053483, AR48940, AI063274, AR052125, AR043247 and OCAST # HR08-037.

222 THE USE OF IN VITRO FERTILIZATION TO STUDY BOVINE IDIOPATHIC INFERTILITY

A 4-year-old beef bull underwent a breeding soundness evaluation at the Western College of Veterinary Medicine (Veterinary Hospital, University of Saskatchewan); no apparent abnormalities were observed after conventional semen evaluations. However, the clinical history of this bull indicated that no pregnancies resulted from natural service of 52 cycling cows over a period of 2 years. Completed services were observed. The objective of this study was to use in vitro fertilization (IVF) technology to evaluate whether the sperm from this infertile bull could successfully fertilize oocytes in vitro. Fresh semen was collected with an electroejaculator and frozen in a computer-controlled rate freezer. Concentration and motility parameters were assessed by using computer-assisted semen analyses. Sperm morphology was evaluated on eosin-nigrosin-stained slides, and Coomassie blue staining was used to evaluate the presence of intact acrosomes. Within each evaluation technique, frozen–thawed semen from bulls (n = 2) with proven fertility was used as a positive control and samples of dead sperm (produced by repeated frozen–thawed cycles until reaching no sperm motility) were used as a negative control. Frozen semen from the infertile bull was used for IVF assay. Data were analyzed by ANOVA (sperm motility and the presence of acrosomes) or the chi-square test (cleavage and blastocyst rates), with a P-value of 0.05. Our infertile bull showed an average motile sperm percentage of 91.7 ± 2.2%, with 78.6 ± 3.5% progressive motility. After cryopreservation procedures, frozen–thawed semen had an acceptable general and progressive percentage of motility of 57.8 ± 6.7% and 43.9 ± 9.2%, respectively. Sperm stained with Coomassie blue showed a greater proportion of intact acrosomes in the fresh semen (63.6 ± 4.3% v. 40.4 ± 3.7%; P < 0.05); however, frozen–thawed semen from both the fertile bull and the control were similar (40.4 ± 3.7b% v. 45.5 ± 2.2b%, P < 0.05). In vitro fertilization results revealed a low cleavage rate at 48 h postfertilization (19.8 ± 6.3%) and blastocyst rate (2.4 ± 2.8%) when using frozen–thawed semen from the infertile bull, compared with the control (56.7 ± 8.2% and 26.3 ± 4.5%, respectively; P < 0.001). Moreover, cleavage and blastocyst rates obtained by using the negative control (21.1 ± 3.2% and 1.1 ± 1.9%, respectively) were similar to those of the infertile bull (P > 0.10). It was noted that ova fertilized with either frozen–thawed semen from the infertile bull or the negative control did not produce blastocysts before Days 8 and 9 of embryo culture, which is a characteristic of parthenogenesis. The results from this IVF study suggest that in this bull, there was a missing or defective factor blocking one of the steps in the fertilization process. Further investigations to identify this factor will increase our knowledge of male fertility, and could lead to new methods of evaluating and regulating fertilizing ability.

224 A COMPARATIVE STUDY BETWEEN WOOD AND PLAINS BISON

In Canada, brucellosis and tuberculosis threaten an estimated 4500 wood bison (Bison bison athabascae), a species considered at risk by the Committee on the Status of Endangered Wildlife In Canada (COSEWIC). To help rescue this species, our Wood Bison Reproductive Research group proposes to employ advanced reproductive technologies. Unfortunately, little is known about the reproductive physiology of the wood bison, which hinders the application of these reproductive technologies. In order to modify advanced reproductive techniques developed in cattle for use in wood bison, the large amounts of semen, embryos, and oocytes from wood bison required are not available. The purpose of this study was to compare semen collected from the more abundant and closely related plains bison (Bison bison bison) with that of wood bison. Semen from 3 wood and 4 plains bison were collected by electro-ejaculation during the summer of 2007. Andrological parameters of morphology and motility were recorded on fresh semen, extended semen, and post-thawed semen samples. A Student's t-test was used to compare the results of these two groups. Semen was cryopreserved using two commercially available cryopreservation media (Andromed and Triladyl, Minitube Canada, Ingersoll, Ontario, Canada). Sperm morphology and motility were not different between electro-ejaculated samples from plains and wood bison (P > 0.05). Also, no difference was found in the survival rate of sperm from the electro-ejaculated samples between plains and wood bison after freezing and then thawing using an egg-yolk based extender (Triladyl) or an extender containing no products of animal origin (Andromed). A difference between cryopreservation media was found; post-thaw motility of Triladyl-treated sperm was higher (29%) than that of the Andromed-treated sperm (12%). Due to lack of previous success with preserving electro-ejaculated semen in media free of animal-origin products, motility assays were performed to evaluate if spermatozoa retrieved from epididymides of plains bison can be cryopreserved in Andromed. Interestingly, cyropreserved epididymal spermatozoa had a higher motility than cryopreserved electro-ejaculated sperm after freezing-thawing procedures using a medium containing no products of source animal (respectively, 30% v. 7%). This result suggests that there may be a factor secreted by the reproductive accessory glands that interferes with the post-thaw survivability of bison sperm. In conclusion, this study supports the hypothesis that semen from plains bison behaves similarly to that of wood bison semen during cryopreservation and therefore could be used to establish protocols for advanced reproductive technologies in wood bison. This project was supported by Canadian Adaptation and Rural Development in Saskatchewan.

Mutagenesis-generated mouse models of human infertility with abnormal sperm

BACKGROUND

The aetiology of human male fertility, with impairment of sperm number, motility and morphology (oligoasthenoteratozoospermia), has been difficult to understand, partly for lack of animal models.

METHODS

An ethylnitrosourea (ENU) mutagenesis strategy has been successful in producing heritable gene mutations with phenotypes similar to human male infertility, and here, we describe three independent ENU-induced mutations that cause a phenotype of oligoasthenoteratozoospermia in mice.

RESULTS

The loci identified by these three mutations are designated swm2, repro2 and repro3. All mutant males were characterized by low sperm concentration, poor sperm morphology and negligible motility, but the infertile males were apparently normal in other respects. Sperm from mutant males failed to fertilize oocytes in vitro. Ultrastructural analyses revealed varied abnormalities apparent in both testicular spermatids and epididymal sperm. Genetic mapping placed the swm2 gene on chromosome 7, the repro2 gene on chromosome 5 and the repro3 gene on chromosome 10.

CONCLUSION

The single-gene mutations caused complex and non-specific sperm pathologies, a point with important implications for managing cases of human male infertility. The ultimate identification of the loci for the mutations causing these phenotypes will clarify aetiology of complex syndromes of infertility with sperm abnormalities consistent with oligoasthenoteratozoospermia.

New mouse genetic models for human contraceptive development

Genetic strategies for the post-genomic sequence age will be designed to provide information about gene function in a myriad of physiological processes. Here an ENU mutagenesis program (http://reprogenomics.jax.org) is described that is generating a large resource of mutant mouse models of infertility; male and female mutants with defects in a wide range of reproductive processes are being recovered. Identification of the genes responsible for these defects, and the pathways in which these genes function, will advance the fields of reproduction research and medicine. Importantly, this program has potential to reveal novel human contraceptive targets.

Cryopreservation alters the levels of the bull sperm surface protein P25b

Fertility of frozen-thawed bull sperm is reduced by cryopreservation. Freezing-thawing procedures can result in as much as a sevenfold fertility decrease. Sperm mortality and loss of motility do not fully explain the reduced fertility of cryopreserved semen; they may be partially explained by the loss of sperm surface proteins, which are necessary for fertilization. We have previously identified P25b, a sperm surface protein, which is associated with the fertility index of bulls used for artificial insemination. Using Western blotting techniques, we have evaluated P25b levels before and after cryopreservation of bull spermatozoa in extenders based on either egg yolk or milk. Long storage periods (28 days) in liquid nitrogen results in a threefold decrease of P25b levels associated with cryopreserved versus fresh spermatozoa. Over a short storage period (3-7 days), a stable P25b level was observed on spermatozoa cryopreserved in extender containing either egg yolk or milk. A decrease in P25b levels associated with spermatozoa was observed after 5 days of storage in egg yolk extender, whereas a significant decrease was observed after 14 days of sperm storage in milk extender (P < .05). Therefore, the loss of P25b may be responsible, at least in part, for the decrease in fertility following the freezing-thawing procedure of bull semen. Moreover, the cryopreservation extender used may have different effects on the loss of sperm surface proteins after even brief storage periods in liquid nitrogen. Considering that a sperm protein similar to P25b exists in humans (P34H), these results may have significant clinical applications in which frozen semen is used.

Encapsulation of foscarnet in liposomes modifies drug intracellular accumulation, in vitro anti-HIV-1 activity, tissue distribution and pharmacokinetics

OBJECTIVE

To improve the in vitro anti-HIV-1 activity, intracellular accumulation in macrophages and in vivo pharmacokinetics and tissue distribution of foscarnet (trisodium phosphonoformate; PFA) by encapsulation in liposomes.

METHODS

The accumulation of free and liposome-encapsulated PFA was determined in monocyte-macrophage RAW 264.7 cells and human premonocytoid U937 cells. The antiviral activity was evaluated in U937 cells infected with HIV-1IIIB. Tissue distribution and pharmacokinetics of free and liposomal PFA were determined in female Sprague-Dawley rats following the administration of an intravenous bolus dose (10 mg PFA/kg).

RESULTS

The entrapment of PFA in liposomes resulted in a higher drug accumulation in both U937 and RAW 264.7 cells. A slightly greater efficacy against HIV-1IIIB replication into U937 cells was observed upon encapsulation of PFA into liposomes. Improved pharmacokinetics was observed upon entrapment of PFA in liposomes. Much higher drug levels were found in plasma for the liposomal formulation. The systemic clearance of the liposomal drug was 77 times lower than that of free drug. The encapsulation of PFA in liposomes greatly enhanced the drug accumulation in organs of the reticuloendothelial system.

CONCLUSION

The encapsulation of PFA in liposomes modified the tissue distribution and plasma pharmacokinetics of the antiviral agent, resulting in a marked improvement of drug accumulation in organs involved in HIV immunopathogenesis and in a greater PFA bioavailability. The antiviral activity of liposomal PFA was slightly greater than that of free drug in HIV-1IIIB-infected U937 cells.

The RNA of both polarities of the peach latent mosaic viroid self-cleaves in vitro solely by single hammerhead structures

Hammerhead self-cleavage of dimeric, monomeric, truncated and mutated transcripts derived from both polarities of the peach latent mosaic viroid (PLMVd) were characterized. In contrast to some results previously published for a very close sequence variant (see ref. 1), these RNAs exhibit a virtually identical self-cleavage during transcription and after purification. By self-cleavage of dimeric transcripts with normal and mutated hammerhead domains and by complementation experiments, we show that the cleavage reactions involve only single hammerhead structures. This observation contrasts with the case of avocado sunblotch viroid (ASBVd), the other self-cleaving viroid, whose mechanism involves mostly double hammerhead structures, whereas single hammerhead cleavage is associated with viroid-like plant satellite RNAs. The difference in stability between the native secondary structures adopted by viroids and the autocatalytic structures, including the hammerhead motif, governs the efficiency of the self-cleavage reaction. The transition between these conformers is the limiting step in catalysis and is related exclusively to the left arm region of PLMVd secondary structure, which includes the hammerhead sequences. Most of the mutations between the variant we used and the sequence variant previously published are located in this left arm region, which may explain to a great extent the differences in their cleavage efficiency. No interactions with long-range sequences contributing to the autocatalytic tertiary structure were revealed in these experiments.

Uptake and binding of liposomal 2',3'-dideoxycytidine by RAW 264.7 cells: a three-step process

It was recently reported that the sequestration of virus by macrophages in reticuloendothelial system organs, such as lymph nodes, is possibly responsible for the clinical latency of disease in asymptomatic HIV-infected patients. Since macrophages may sequester HIV after phagocytosis, and because phagocytosis is a specialized function of any mammalian macrophage, a mouse-macrophage cell line (RAW 264.7) was used as a macrophage model to evaluate the uptake and binding of 2',3'-dideoxycytidine (ddC) encapsulated in liposomes of an average size of 300 nm containing 350 mumols of ddC per mmol of lipids. Liposomal ddC (L-ddC) was rapidly taken up by macrophages. In contrast, its free form (ddC) accumulated slowly in these cells. The accumulation of ddC from L-ddC into cells seemed to consist of two components: a saturable one, which fitted with the Michaelis-Menten model, and a nonsaturable one, which proceeded linearly in the presence of an excess amount of unlabeled liposomes. Under these conditions, we found an apparent Michaelis-Menten constant (Km) of 40 microM and an initial velocity of 0.12 nmol ddC/mg protein/min for the saturable component and a constant rate of accumulation (KN) of 0.017/min for the nonsaturable component. The inhibition of uptake of ddC from L-ddC in the presence of phagocytosis inhibitors (deoxyglucose plus sodium azide) and nucleoside transport inhibitors (dipyridamole or nitrobenzylthioinosine) also confirmed the existence of several mechanisms in the liposome-mediated accumulation process of ddC into macrophages. Furthermore, studies of efflux of ddC in drug-free medium from cells preloaded with L-ddC or ddC established longer retention of ddC in cells preloaded with L-ddC than with ddC.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of cellular accumulation, tissue distribution, and anti-HIV activity of free and liposomal 2',3'-dideoxycytidine

We have investigated the cellular accumulation, tissue distribution, and antihuman immunodeficiency virus activity of free dideoxycytidine (ddC) and liposomal ddC (L-ddC). We have found that L-ddC was more efficiently taken up than its free form by RAW 264.7 cells (a monocyte-macrophage cell line) (p < 0.01) while a comparable uptake was seen in U937 cells (a promonocytic cell line). In the rat, L-ddC accumulated preferentially in liver and spleen when injected intravenously (p < 0.01), and mostly in spleen when given intraperitoneally (p < 0.01). In contrast, free ddC was rapidly eliminated out of the body. Liposomal ddC showed a similar anti-HIV activity in comparison with free ddC in U937 cells. Given the fact that encapsulation of ddC in liposomes does not affect its anti-HIV activity but enhances its in vitro cellular accumulation and its in vivo distribution in reticuloendothelial system (RES) tissues, we conclude that ddC in liposomal formulation is a promising anti-HIV agent with a targeted action on the RES, which is considered a reservoir for dissemination of virus to other cells, tissues, and organs.

L-651,392, a potent leukotriene inhibitor, controls inflammatory process in Escherichia coli pyelonephritis

In this study, the relationship between leukotrienes, peritubular cell infiltration with polymorphonuclear cells (PMNs) and renal tubular damage was investigated in a rat model of acute ascending pyelonephritis. Infection was induced by the injection of 10(5) CFU of Escherichia coli into the bladder and occlusion of the left ureter for 24 h. Treatment of infected animals was started 24 h after the induction of pyelonephritis with either hydrocortisone (25 mg/kg of body weight per day), the leukotriene inhibitor L-651,392 (10 mg/kg/day), or the vehicle of L-651,392 and was maintained for 5 days. At the end of treatment, the animals were killed, serum was collected, and both kidneys were removed for colony counts and histopathology. Renal function was evaluated by the measurement of blood urea nitrogen levels and creatinine clearance. The numbers of PMNs and mononuclear cells (MNs) in the cortex and medulla were recorded for all groups on plastic sections done from the left kidney. Infection alone (vehicle of L-651,392) resulted in intensive interstitial infiltration and a severe tubular destruction in the cortex. Treatment with hydrocortisone did not prevent PMN migration and tissue damage. By contrast, treatment with L-651,392 resulted in a significant reduction in PMNs (P < 0.001 in comparisons with all other groups) and greater preservation of the tubular structure despite identical bacterial counts than in the group receiving hydrocortisone. We conclude that L-651,392 prevents inflammatory cells from reaching the site of infection and protects the kidney from tubular damage associated with inflammation during pyelonephritis. Inhibitors of leukotrienes should be further investigated for their potential benefit as adjuvants to antibiotherapy in the treatment of pyelonephritis.

Daptomycin may attenuate experimental tobramycin nephrotoxicity by electrostatic complexation to tobramycin

The lipopeptidic antibiotic daptomycin is reported to reduce experimental tobramycin nephrotoxicity (D. Beauchamp, M. Pellerin, P. Gourde, M. Pettigrew and M. G. Bergeron, Antimicrob. Agents Chemother. 34:139-147, 1990; C. A. Wood, H. C. Finkbeiner, S. J. Kohlhepp, P. W. Kohnen, and D. C. Gilbert, Antimicrob. Agents Chemother. 33:1280-1285, 1989). In an attempt to explain these results, the in vivo and in vitro interactions between daptomycin and tobramycin were studied. Tobramycin alone and preincubated with negatively charged phospholipid bilayers (liposomes) was dialyzed against increasing concentrations of daptomycin in buffer at pH 5.4. A significant drop in the concentration of tobramycin was observed when daptomycin was added to the opposite half cells. Furthermore, daptomycin induced a concentration-dependent release of lipid-bound tobramycin. Gold labeling experiments showed that daptomycin could be incorporated into phospholipid layers. Female Sprague-Dawley rats were treated with daptomycin alone, with tobramycin alone, or with the combination over 2 to 10 days. Levels of daptomycin and tobramycin in serum were similar in all groups. The levels of tobramycin in the renal cortex increased significantly with time and, on day 10, reached values of 654 +/- 122 and 844 +/- 298 micrograms/g of tissue (mean +/- standard deviation; not significant) in animals treated with tobramycin and the combination of daptomycin-tobramycin, respectively. No significant difference was observed in the levels of tobramycin in the kidneys between animals treated with tobramycin or the daptomycin-tobramycin combination at any time. By contrast, daptomycin levels were significantly higher in the renal cortexes of animals treated with daptomycin-tobramycin in comparison with those in the renal cortexes of animals treated with daptomycin alone on days 6,8, and 10 (P < 0.01). For immunogold labeling studies, animals were killed 4 h after a single injection of daptomycin alone or daptomycin in combination with tobramycin. Daptomycin was found throughout the matrixes of the lysosomes of proximal tubular cells of animals treated with daptomycin alone. In animals treated with the combination of daptomycin and tobramycin, daptomycin was associated with intralysosomal myeloid bodies. Our results suggest that daptomycin might attenuate experimental aminoglycoside nephrotoxicity by interacting with the aminoglycoside, perhaps electrostatically, and thereby protecting intracellular targets of toxicity.

Antibiotic susceptibility profiles of 941 gram-negative bacteria isolated from septicemic patients throughout Canada. The Canadian Study Group

The choice of antimicrobial therapy for the treatment of bacteremia is often empirical and based on the knowledge of antibiotic susceptibility profiles of the most common bacteria causing such infections. It therefore is crucial to survey the susceptibility of bacteria causing sepsis. This study examines the susceptibility profiles of 941 gram-negative bacteria, isolated from septic patients in 10 Canadian hospitals, to 28 antimicrobial agents. Among the isolates, 30 different species were represented; Escherichia coli dominated, representing 52.5% of isolates. More than 50% of all bacteria were resistant to ampicillin. Only 67% of the E. coli isolates were susceptible to ampicillin, while 30% of all strains were resistant to ticarcillin. Of the cephalosporins, ceftazidime and cefoperazone/sulbactam were the agents to which isolates were the most susceptible (90%). Only 51% of the E. coli strains were susceptible to cephalothin, while 91% were still susceptible to cefazolin. A total of 93% and 98% of the strains were susceptible to aztreonam and imipenem, respectively. Aminoglycosides were highly active against most isolates, in general in the following order: netilmicin greater than tobramycin greater than gentamicin greater than amikacin. Tobramycin was the most active against Pseudomonas aeruginosa. Nearly all isolates were susceptible to the quinolones. Tolerance (MBC/MIC ratio, greater than or equal to 32) was rarely observed. This survey of the susceptibility of gram-negative bacteria causing sepsis provides valuable information for implementing the chemotherapy for gram-negative septicemia and demonstrates that several older and newer agents, alone or in combination, can be used as adequate initial therapy for gram-negative sepsis in Canada.

Concentrations of teicoplanin in serum and atrial appendages of patients undergoing cardiac surgery

The concentrations of teicoplanin in sera and heart tissues of 49 patients undergoing coronary bypass were measured. Each patient received a 6- or 12-mg/kg dose of teicoplanin administered in a slow intravenous bolus injection over 3 to 5 min beginning at the time of induction of anesthesia. Mean +/- standard error of the mean concentrations in serum were, for the two doses, respectively, 58.1 +/- 1.7 and 123.3 +/- 7.4 micrograms/ml 5 min after administration and 22.2 +/- 0.7 and 56.5 +/- 2.8 micrograms/ml at the time of removal of atrial appendages. Mean +/- standard error of the mean concentrations in tissue were 70.6 +/- 1.7 and 139.8 +/- 2.2 micrograms/g, respectively, giving mean tissue/serum ratios of 3.7 +/- 0.3 and 2.8 +/- 0.2, respectively. Teicoplanin penetrates heart tissue readily and reaches levels in the serum far in excess of the MICs for most pathogens that have been found to cause infections following open heart surgery.

Enoxacin penetration into human prostatic tissue

Concurrent enoxacin concentrations in serum and prostatic tissue were determined in 14 patients. The mean ratios of enoxacin concentration in tissue over concentration in serum were 1.4 +/- 0.2 (standard error of the mean). The levels in serum and prostatic tissue were above the MICs for most urinary pathogens.

Renal pharmacokinetic changes of gentamicin during enterococcal pyelonephritis

In the present study, the renal pharmacokinetics of gentamicin was investigated in pyelonephritic rats infected with Streptococcus (Enterococcus) faecalis. Four days after the induction of infection, animals were given either a single dose of gentamicin or two daily injections for 7 days. The treated animals were evaluated from 1 h to 6 months posttreatment. After a single injection, limited pharmacokinetic variations were observed, whereas after 14 injections infected kidneys demonstrated significantly higher concentrations and a more extended renal elimination phase of the antibiotic. Analysis of the area under the curve of the concentration in kidney versus time showed more marked renal accumulation by the infected and long-term treated animals than by normal animals or those receiving only one injection of aminoglycoside. Renal function remained normal in both the infected and normal animals treated with this aminoglycoside. These results demonstrate that S. faecalis pyelonephritis disturbs the renal handling of gentamicin and may increase the susceptibility of the kidney to aminoglycosides.

In-vitro uptake of gentamicin and tobramycin by rat renal tubules in the presence or absence of Escherichia coli endotoxin

Renal tubules of rats were incubated with aminoglycoside (gentamicin or 3H-tobramycin, 10 mg/l) in the presence or absence of Escherichia coli endotoxin (10 mg/l). The kinetics of aminoglycoside uptake by the tubule were only slightly affected by endotoxin. The percentage of serum in the medium affected the tobramycin uptake. This uptake decreased from a mean ratio of concentration in the tubules/concentration in the medium (T/M) of 1.63 in 5% serum to a mean T/M of 0.86 in 10% serum (P less than 0.01).

Norfloxacin penetration into human renal and prostatic tissues

Concurrent norfloxacin concentrations in serum, kidney, and prostatic tissue were determined in 14 patients. Mean ratios of norfloxacin concentration in tissue over concentration in serum were 6.6 +/- 2.8 for the kidney and 1.7 +/- 0.2 for the prostate samples. The levels were above the MICs of most urinary pathogens.

Concentrations of fusidic acid, cloxacillin, and cefamandole in sera and atrial appendages of patients undergoing cardiac surgery

The concentrations of cefamandole, cloxacillin and fusicid acid were measured in the serum and heart tissue of 100 recipients of these drugs before cardiac surgery. During cardiopulmonary bypass, mean (+/- standard deviation) peak concentrations in serum of all patients were 63.0 +/- 34.0 micrograms of cefamandole per ml, 30.8 +/- 17.7 micrograms of cloxacillin per ml, and 32.4 +/- 10.8 micrograms of fusidic acid per ml. Mean (+/- standard deviation) concentrations in atrial appendages taken 1 h (+/- 15 min) after infusion were 21.3 +/- 11.0 micrograms of cefamandole per g, 23.8 +/- 17.3 micrograms of cloxacillin per g, and 10.7 +/- 4.2 micrograms of fusidic acid per g. No cloxacillin could be detected in 5 of 39 heart specimens. Mean tissue-to-serum ratios at 1 h for cefamandole, cloxacillin, and fusidic acid were respectively 0.35, 0.73, and 0.33. Fusidic acid, a drug which is highly effective in vitro against both methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis, was detectable in heart tissue in concentrations which were 12 times higher than the MICs of this agent against these resistant microorganisms.

Three to eight weeks of therapy with netilmicin: toxicity in normal and diabetic patients

Twenty-eight patients, 24 men and 4 women, aged between 17 and 72 years old, and suffering from chronic osteomyelitis (19), mastoiditis (5), or serious wound infections (4) were treated for an average of 35 days with netilmicin at doses of 2.4 to 6.9 mg/kg/day. The total dose of netilmicin given to each patient ranged from 3700 to 23 220 mg. Although the renal function was initially normal in all patients and stayed normal throughout therapy in all patients with no underlying disease, netilmicin nephrotoxicity was detected in two diabetic patients (7.6%). Vestibular toxicity developed in two (7.6%) but no change in audiograms was noted. Long-term therapy was associated with a significant increase (P less than 0.001) in half-life, from 1.5 to 1.9 h, and AUC 7.9 to 13.1 mg/l/h.

Disturbed intrarenal distribution of gentamicin in experimental pyelonephritis due to Escherichia coli

The intracortical, medullary, and papillary distribution of gentamicin was studied in normal and pyelonephritic rats. The animals were evaluated from 1 hr to 365 days after the end of therapy with either a single dose or two daily injections given every 12 hr for seven days. The serum levels of gentamicin at 1 hr were significantly (P less than 0.001) higher in the pyelonephritic rats than in the normal rats after one dose (26 vs. 12 microgram/ml) and 14 doses (25.7 vs. 8.8 microgram/ml). Peak concentrations or gentamicin in all parts of infected kidneys were significantly (P less than 0.001) higher than in normal kidneys. Gentamicin was still detectable at levels of 1.2 microgram/g in the cortex of one pyelonephritic animal one year after the end of therapy, when the levels of both serum creatinine (1.1 mg/100 ml) and blood urea nitrogen (30 mg/100 ml) were much higher than at seven days after the end of therapy (0.5 and 19 mg/100 ml, respectively).

Significance of intrarenal concentrations of gentamicin for the outcome of experimental pyelonephritis in rats

The significance of continuous intrarenal levels of gentamicin in the treatment of acute pyelonephritis due to Echerichia coli was investigated in rats. Treatment was started 24 hr after E. coli was injected into the left kidney. A single dose or three successive doses (10 mg/kg of body weight) of gentamicin administered ip every 8 hr could not sterilize the kidneys. Injections of gentamicin (10 mg/kg) every 12 hr for seven or 14 days resulted in continuous levels of the drug in the medulla that persisted above the minimal inhibitory concentration for E. coli (1.6 microgram/ml) for six months or more. Whereas greater than or equal to 73% of the right kidneys or urine specimens were found to be sterile up to six months following a week of therapy, only 23% of the left kidneys were sterile. Two weeks of treatment sterilized greater than or equal to 86% of the left kidneys, right kidneys, and urine specimens. Concentrations of drug in serum and urine were poor predictors of both the intrarenal distribution of drug and the outcome of pyelonephritis.

Intrarenal distribution of trimethoprim and sulfamethoxazole

In the present study, rats were given trimethoprim (TMP, 10 mg/kg), sulfamethoxazole (SMZ, 50 mg/kg), or a combination of the respective doses of TMP and SMZ. Thirty-six rats received each of the drugs studied. Six recipients of a compound (or mixture) were evaluated hourly, from 1 to 6 h after intraperitoneal injection of the agent. At each timed interval, serum, urine, cortex, medulla, and papilla were analyzed for drug content. Peak serum values of 1.1 microgram of TMP and 131.1 microgram of active SMZ (nonacetylated sulfonamide) per ml were observed after injection of the combination TMP-SMZ. Although the cortical, medullary, and papillary TMP concentrations were severalfold higher than the respective serum values (P < 0.01), microbiologically active SMZ did not concentrate in the renal parenchyma and was found in lower concentration there than in the serum (P < 0.01). The levels of SMZ in all parts of the kidney of animals which received the mixture SMZ-TMP were lower than those detected in the animals which were given SMZ alone. The average ratio of active SMZ to TMP within the medulla and the papilla was less than 20 to 1 in the first 2 h. The intrarenal distribution of these drugs may have therapeutic implications.