Single Cell Transcriptomics Implicate Novel Monocyte and T Cell Immune Dysregulation in Sarcoidosis

Sarcoidosis is a systemic inflammatory disease characterized by infiltration of immune cells into granulomas. Previous gene expression studies using heterogeneous cell mixtures lack insight into cell-type-specific immune dysregulation. We performed the first single-cell RNA-sequencing study of sarcoidosis in peripheral immune cells in 48 patients and controls. Following unbiased clustering, differentially expressed genes were identified for 18 cell types and bioinformatically assessed for function and pathway enrichment. Our results reveal persistent activation of circulating classical monocytes with subsequent upregulation of trafficking molecules. Specifically, classical monocytes upregulated distinct markers of activation including adhesion molecules, pattern recognition receptors, and chemokine receptors, as well as enrichment of immunoregulatory pathways HMGB1, mTOR, and ephrin receptor signaling. Predictive modeling implicated TGFβ and mTOR signaling as drivers of persistent monocyte activation. Additionally, sarcoidosis T cell subsets displayed patterns of dysregulation. CD4 naïve T cells were enriched for markers of apoptosis and Th17/T(reg) differentiation, while effector T cells showed enrichment of anergy-related pathways. Differentially expressed genes in regulatory T cells suggested dysfunctional p53, cell death, and TNFR2 signaling. Using more sensitive technology and more precise units of measure, we identify cell-type specific, novel inflammatory and regulatory pathways. Based on our findings, we suggest a novel model involving four convergent arms of dysregulation: persistent hyperactivation of innate and adaptive immunity via classical monocytes and CD4 naïve T cells, regulatory T cell dysfunction, and effector T cell anergy. We further our understanding of the immunopathology of sarcoidosis and point to novel therapeutic targets

Concordant peripheral lipidome signatures in two large clinical studies of Alzheimer’s disease

© 2020, The Author(s). Changes to lipid metabolism are tightly associated with the onset and pathology of Alzheimer’s disease (AD). Lipids are complex molecules comprising many isomeric and isobaric species, necessitating detailed analysis to enable interpretation of biological significance. Our expanded targeted lipidomics platform (569 species across 32 classes) allows for detailed lipid separation and characterisation. In this study we examined peripheral samples of two cohorts (AIBL, n = 1112 and ADNI, n = 800). We are able to identify concordant peripheral signatures associated with prevalent AD arising from lipid pathways including; ether lipids, sphingolipids (notably GM3 gangliosides) and lipid classes previously associated with cardiometabolic disease (phosphatidylethanolamine and triglycerides). We subsequently identified similar lipid signatures in both cohorts with future disease. Lastly, we developed multivariate lipid models that improved classification and prediction. Our results provide a holistic view between the lipidome and AD using a comprehensive approach, providing targets for further mechanistic investigation

Transudative pleural effusion of malignant etiology: Rare but real

A 62-year-old female presented to the emergency room with one-month history of epigastric abdominal pain, nausea and vomiting. She endorsed progressive dyspnea over two weeks. CT of the abdomen demonstrated bilateral pleural effusions and pancreatic inflammation, so the working diagnosis was pancreatitis. A diagnostic thoracentesis was performed and the pleural fluid analysis was classified as transudate by Light's criteria. Given the atypical features in history and concern for malignancy, fluid was sent for cytological examination and immunohistochemistry which suggested a mucinous malignancy. EGD revealed poorly differentiated signet ring cell adenocarcinoma of stomach. Patient underwent placement of indwelling pleural catheters for symptomatic improvement and was discharged to hospice. The decision whether to routinely send transudative effusions for cytological evaluation remains controversial. This case demonstrates the importance of using clinical judgement to guide that decision

Fig 2 -

Kaplan-Meier survival curves a. in high-dose and low-dose groups and b. for subgroups with OSCI = 5 at randomization.</p

Hyperglycemia and infection events in the low-dose group and high-dose group.

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Clinical improvement using the WHO-Ordinal scale for clinical improvement (WHO-OSCI).

Clinical improvement using the WHO-Ordinal scale for clinical improvement (WHO-OSCI).</p

Concordant peripheral lipidome signatures in two large clinical studies of Alzheimer’s disease.

Changes to lipid metabolism are tightly associated with the onset and pathology of Alzheimer’s disease (AD). Lipids are complex molecules comprising many isomeric and isobaric species, necessitating detailed analysis to enable interpretation of biological significance. Our expanded targeted lipidomics platform (569 species across 32 classes) allows for detailed lipid separation and characterisation. In this study we examined peripheral samples of two cohorts (AIBL, n = 1112 and ADNI, n = 800). We are able to identify concordant peripheral signatures associated with prevalent AD arising from lipid pathways including; ether lipids, sphingolipids (notably GM3 gangliosides) and lipid classes previously associated with cardiometabolic disease (phosphatidylethanolamine and triglycerides). We subsequently identified similar lipid signatures in both cohorts with future disease. Lastly, we developed multivariate lipid models that improved classification and prediction. Our results provide a holistic view between the lipidome and AD using a comprehensive approach, providing targets for further mechanistic investigation

Identification of concordant plasma lipid signatures in Alzheimer’s disease: Validation between two independent studies of Alzheimer’s disease

Background: Changes to lipid metabolism are tightly coupled to the onset and pathology of Alzheimer’s disease (AD). Lipidomics has allowed for unprecedented characterisation of the lipidome within biological systems. To explore the lipid dysregulation associated with AD, we utilised our expanded lipidomics platform, examining 569 lipid species across 32 lipid classes, and applied it to the Australian Imaging, Biomarker & Lifestyle Study of Ageing (AIBL) study and the Alzheimer\u27s Disease Neuroimaging Initiative (ADNI) study. Method: We examined over 4000 samples between the AIBL and ADNI studies. Baseline samples comprises of 1112 and 804 from the AIBL and ADNI respectively. Univariate associations between lipids and AD were examined using logistic or linear regressions accounting for variables including anthropometric measures and APOE genotype. Cox regression analysis was used to identify lipids associated with future onset of AD from baseline samples. We utilised a fixed effect model to meta analyse the results, identifying lipids which are concordantly associated between the two studies. Result: Exploratory analysis of the data identified strong associations between plasma lipids and AD risk factors such as age (increasing acylcarnitine species), sex (sphingoid base specific) and APOE genotype (ether lipids). Combined meta‐analysis of the two cohorts identified lipid class and subclass‐specific associations with incident and established AD. In the fully adjusted analysis (anthropometric measures, APOE genotype, clinical lipids and medication), a total of 218 species were associated with established AD and 71 with incident AD after correction for FDR. Sphingomyelin, ceramide, ganglioside, plasmalogen and other ether lipids were concordantly associated with AD and its risk factors in both studies. In particular, ether lipids were consistently associated with both established and future AD independent of their subclass (plasmalogen vs non‐plasmalogen) highlighting impairment of peroxisomal function at the earliest stages of AD. Whole lipid class associations were seen with phosphatidylethanolamine and triglyceride, despite adjustments for clinical lipids, implicating dysregulation in liver lipid metabolism. Conclusion: By leveraging off two independent studies, we were able to highlight concordant associations between lipids and both established and incident AD. The significantly broader coverage of the lipidome from our platform provides new hypotheses and directions for future research