The Parkinson's Disease Protein LRRK2 Interacts with the GARP Complex to Promote Retrograde Transport to the trans-Golgi Network

Mutations in Leucine-rich repeat kinase 2 (LRRK2) cause Parkinson's disease (PD). However, the precise function of LRRK2 remains unclear. We report an interaction between LRRK2 and VPS52, a subunit of the Golgi-associated retrograde protein (GARP) complex that identifies a function of LRRK2 in regulating membrane fusion at the trans-Golgi network (TGN). At the TGN, LRRK2 further interacts with the Golgi SNAREs VAMP4 and Syntaxin-6 and acts as a scaffolding platform that stabilizes the GARP-SNAREs complex formation. Therefore, LRRK2 influences both retrograde and post-Golgi trafficking pathways in a manner dependent on its GTP binding and kinase activity. This action is exaggerated by mutations associated with Parkinson's disease and can be blocked by kinase inhibitors. Disruption of GARP sensitizes dopamine neurons to mutant LRRK2 toxicity in C. elegans, showing that these pathways are interlinked in vivo and suggesting a link in PD.

FRI0285 FILGOTINIB TREATMENT RESULTS IN REDUCTION OF BIOMARKERS ASSOCIATED WITH DISEASE IN PATIENTS WITH ANKYLOSING SPONDYLITIS

Background:

Ankylosing spondylitis (AS) is a chronic, immune-mediated disease characterized by inflammation of the sacroiliac joints and spine, and a young age of onset of 20–40 years. In the recent TORTUGA study, filgotinib (FIL), an oral, selective Janus kinase 1 (JAK1) inhibitor, significantly reduced AS disease activity compared with placebo (PBO).1Selective JAK1 inhibition by FIL has the potential to simultaneously block multiple inflammatory pathways, thus we analyzed biomarker concentrations in serum samples from TORTUGA.

Objectives:

To evaluate the impact of selective JAK1 inhibition with FIL on circulating disease associated biomarkers in adult patients with active AS enrolled in the TORTUGA study.

Methods:

TORTUGA (Clinicaltrials.gov identifierNCT03117270) was a 12-week, randomized, double-blind, placebo-controlled, phase 2 study. Patients were randomized 1:1 to FIL 200 mg (n=58) or PBO (n=58) once-daily. Serum samples (FIL n=56, PBO n=53) were collected at baseline (BL) and weeks 1, 4 and 12, and analyzed using the Meso Scale Discovery immunoassay platform (Meso Scale Diagnostics, Rockville, MD, USA) to evaluate 135 biomarkers. Biomarker concentration changes from BL were analyzed on paired patient data and reported for weeks 1, 4 and 12, and clustering analysis was performed. Correlation between the 135 biomarkers and selected clinical scores at BL was assessed by Spearman rank correlation analysis.

Results:

FIL treatment produced significant reductions in serum concentrations of multiple biomarkers associated with AS disease activity. Five clusters of biomarker response were identified based on the kinetics and magnitude of percent changes from BL. These clusters also represented discrete biological functions: cluster 1 (rapid, strong >50% decrease in all three time points) included systemic inflammation biomarkers eg, CRP, SAA; cluster 2 (>20% decrease in at least one time point) included immune cell biomarkers eg, MIP3B, IL12p40; cluster 3 (<20% decrease in all three time points) included cellular adhesion biomarkers eg, ICAM-1, VCAM-1; cluster 4 (delayed decrease) included matrix remodelling biomarkers eg, MMP1, TIMP1; and cluster 5 included biomarkers that exhibited a gradual increase in serum concentration with FIL treatment.

Spearman rank correlation analyses showed that at BL, the systemic inflammation biomarkers CRP and SAA, as well as a number of biomarkers including ICAM-1 and MMP3, were positively correlated with BL AS disease activity score (ASDAS); conversely, only a few biomarkers showed a negative correlation with BL ASDAS, the cytokine receptor FLT3 and the chemotactic cytokine fractalkine (FRACTAL).

Conclusion:

In patients with active AS, FIL treatment significantly decreased levels of circulating biomarkers associated with active AS disease, including proinflammatory cytokines and chemokines, cell adhesion molecules, and markers of matrix remodelling. Clustering analysis revealed early and late biomarker changes associated with disease. These data are consistent with reduced AS disease activity in TORTUGA and suggest that FIL treatment leads to a rapid and sustained reduction of inflammation in AS.

References:

[1]van der Heijde Det al. Lancet2018;392:2378–87

Acknowledgments:

This study was funded by Gilead Sciences, Inc. Editorial support was provided by Fishawack Communications Inc and funded by Gilead Sciences, Inc.

Disclosure of Interests:

Walter P. Maksymowych Grant/research support from: AbbVie, Novartis, Pfizer, and UCB, Consultant of: AbbVie, Boehringer Ingelheim, Celgene, Eli Lilly, Galapagos, Janssen, Novartis, Pfizer, and UCB, Employee of: Chief Medical Officer of CARE Arthritis Limited, Speakers bureau: AbbVie, Janssen, Novartis, Pfizer, and UCB, Yuan Tian Employee of: Gilead Sciences Inc., Oh Kyu Yoon Shareholder of: Gilead Sciences Inc., Employee of: Gilead Sciences Inc., William Barchuk Shareholder of: Gilead Sciences Inc and Eli Lilly, Employee of: Current employee of Gilead Sciences Inc and a former employee of AbbVie, Eli Lilly, and Johnson & Johnson, René Galien Shareholder of: Galapagos, Employee of: Galapagos, Robin Besuyen Shareholder of: Galapagos, Employee of: Galapagos, Yihua Liu Shareholder of: Gilead Sciences Inc., Employee of: Gilead Sciences Inc., Amer M. Mirza Shareholder of: Gilead Sciences Inc., Employee of: Gilead Sciences Inc., Vlad Malkov Shareholder of: Gilead Sciences Inc., Employee of: Gilead Sciences Inc., Angie Hertz Shareholder of: Gilead Sciences Inc, Employee of: Gilead Sciences Inc

Rare disruptive variants in the DISC1 Interactome and Regulome: association with cognitive ability and schizophrenia

Schizophrenia (SCZ), bipolar disorder (BD) and recurrent major depressive disorder (rMDD) are common psychiatric illnesses. All have been associated with lower cognitive ability, and show evidence of genetic overlap and substantial evidence of pleiotropy with cognitive function and neuroticism. Disrupted in schizophrenia 1 (DISC1) protein directly interacts with a large set of proteins (DISC1 Interactome) that are involved in brain development and signaling. Modulation of DISC1 expression alters the expression of a circumscribed set of genes (DISC1 Regulome) that are also implicated in brain biology and disorder. Here we report targeted sequencing of 59 DISC1 Interactome genes and 154 Regulome genes in 654 psychiatric patients and 889 cognitively-phenotyped control subjects, on whom we previously reported evidence for trait association from complete sequencing of the DISC1 locus. Burden analyses of rare and singleton variants predicted to be damaging were performed for psychiatric disorders, cognitive variables and personality traits. The DISC1 Interactome and Regulome showed differential association across the phenotypes tested. After family-wise error correction across all traits (FWERacross), an increased burden of singleton disruptive variants in the Regulome was associated with SCZ (FWERacross P=0.0339). The burden of singleton disruptive variants in the DISC1 Interactome was associated with low cognitive ability at age 11 (FWERacross P=0.0043). These results identify altered regulation of schizophrenia candidate genes by DISC1 and its core Interactome as an alternate pathway for schizophrenia risk, consistent with the emerging effects of rare copy number variants associated with intellectual disability.

Correction: Identification of Novel Pre-Erythrocytic Malaria Antigen Candidates for Combination Vaccines with Circumsporozoite Protein

[This corrects the article DOI: 10.1371/journal.pone.0159449.].

Identification of Novel Pre-Erythrocytic Malaria Antigen Candidates for Combination Vaccines with Circumsporozoite Protein

Malaria vaccine development has been hampered by the limited availability of antigens identified through conventional discovery approaches, and improvements are needed to enhance the efficacy of the leading vaccine candidate RTS,S that targets the circumsporozoite protein (CSP) of the infective sporozoite. Here we report a transcriptome-based approach to identify novel pre-erythrocytic vaccine antigens that could potentially be used in combination with CSP. We hypothesized that stage-specific upregulated genes would enrich for protective vaccine targets, and used tiling microarray to identify P. falciparum genes transcribed at higher levels during liver stage versus sporozoite or blood stages of development. We prepared DNA vaccines for 21 genes using the predicted orthologues in P. yoelii and P. berghei and tested their efficacy using different delivery methods against pre-erythrocytic malaria in rodent models. In our primary screen using P. yoelii in BALB/c mice, we found that 16 antigens significantly reduced liver stage parasite burden. In our confirmatory screen using P. berghei in C57Bl/6 mice, we confirmed 6 antigens that were protective in both models. Two antigens, when combined with CSP, provided significantly greater protection than CSP alone in both models. Based on the observations reported here, transcriptional patterns of Plasmodium genes can be useful in identifying novel pre-erythrocytic antigens that induce protective immunity alone or in combination with CSP.

Gene expression analysis in serial liver fine needle aspirates

No method with low morbidity presently exists for obtaining serial hepatic gene expression measurements in humans. While hepatic fine needle aspiration (FNA) has lower morbidity than core needle biopsy, applicability is limited due to blood contamination, which confounds quantification of gene expression changes. The aim of this study was to validate FNA for assessment of hepatic gene expression. Liver needle biopsies and FNA procedures were simultaneously performed on 17 patients with chronic hepatitis C virus infection with an additional FNA procedure 1 week later. Nine patients had mild/moderate fibrosis and eight advanced fibrosis. Gene expression profiling was performed using Affymetrix microarrays and TaqMan qPCR; pathway analysis was performed using Ingenuity. We developed a novel strategy that applies liver-enriched normalization genes to determine the percentage of liver in the FNA sample, which enables accurate gene expression measurements overcoming biases derived from blood contamination. We obtained almost identical gene expression results (ρ = 0.99, P < 0.0001) comparing needle biopsy and FNA samples for 21 preselected genes. Gene expression results were also validated in dogs. These data suggest that liver FNA is a reliable method for serial hepatic tissue sampling with potential utility for a variety of preclinical and clinical applications.