Project description:Background/Purpose: Systemic lupus erythematosus (SLE) is a complex multi-system autoimmune disease of uncertain etiology. Patients from different ancestral backgrounds demonstrate differences in clinical manifestations and autoantibody profiles. In this study we examined genome-wide transcriptional patterns in major immune cell subsets across different ancestral backgrounds. Methods: Peripheral blood was collected from 21 African-American (AA) and 21 European-American (EA) SLE patients, 5 AA controls, and 5 EA controls. CD4+ T-cells, CD8+ T-cells, monocytes and B cells were purified by flow sorting. Each cell subset from each subject was run on an Illumina HumanHT-12 V4 expression BeadChip array (n=208 arrays). Differentially expressed genes (DEGs) were determined by comparing cases and controls of the same ancestral background. Results: The overlap in DEG lists between different cell types from the same ancestral background was very modest (<1%). Typically between 5-10% of DEGs were shared when comparing the same cell type between different ancestral backgrounds (for ex. CD20 AA vs. CD20 EA). Quantitative measurement of global IFN-stimulated gene (ISG) expression revealed that AA subjects demonstrated more concordance across all studied cell types. Two subgroups of patients were identified based on the ISG expression profiles. One subgroup showed higher ISGs expression in all cell types, and the other subgroup had higherISG expression only in T and B lymphocytes but not in monocytes. The correlation of ISG expression with medication data revealed that only the B cells had lower ISG expression in patients taking immunosuppressants, while ISG expression in the other cell types did not differ based upon medication use. Conclusion: We find striking differences in gene expression between different immune cell subsets and between ancestral backgrounds in SLE patients. The IFN signature is diverse, with different transcripts represented in different cell populations, and signature-positive cell subsets differed in EA vs. AA patients. We also find that treatment with the immunosuppressive agents correlates with the down-regulation of B cell ISG expression, and this was not observed in other cell types. Peripheral blood was collected from 21 African-American (AA) and 21 European-American (EA) SLE patients, 5 AA controls, and 5 EA controls. CD4+ T-cells, CD8+ T-cells, monocytes and B cells were purified by flow sorting. Each cell subset from each subject was run on an Illumina HumanHT-12 V4 expression BeadChip array (n=208 arrays).

Project description:BACKGROUND: SLE is a complex autoimmune disease with deleterious effects on various organs. Accumulating evidence has shown abnormal vitamin B12 and one-carbon flux contribute to immune dysfunction. Transcobalamin II (TCN2) belongs to the vitamin B12-binding protein family responsible for the cellular uptake of vitamin B12. The role of TCN2 in SLE is still unclear.METHODS: We collected clinical information and blood from 51 patients with SLE and 28 healthy controls. RNA sequencing analysis, qPCR and western blot confirmed the alteration of TCN2 in disease monocytes. The correlation between TCN2 expression and clinical features and serological abnormalities was analyzed. TCN2 heterozygous knockout THP1 cells were used to explore the effects of TCN2 dysfunction on monocytes. CCK-8 assay and EdU staining were used to detect cell proliferation. ELISA was conducted to assess vitamin B12, glutathione and cytokines changes. UHPLC-MRM-MS/MS was used to detect changes in the intermediates of the one-carbon cycle. Flow cytometry is used to detect cell cycle, ROS, mitoROS and CD14 changes.RESULTS: Elevated TCN2 in monocytes was correlated positively with disease progression and specific tissue injuries. Using CD14+ monocytes and TCN2 genetically modified THP1 cell lines, we found that the TCN2 was induced by LPS in serum from SLE patients. TCN2 heterozygous knockout inhibited cellular vitamin B12 uptake and one-carbon metabolism, leading to cell proliferation arrest and decreased Toll-like receptor 4 (TLR4)-mediated CCL2 release. Methionine cycle metabolites, s-adenosylmethionine and homocysteine, rescued these effects, whereas folate treatment proved to be ineffective. Folate deficiency also failed to replicate the impact of TCN2 downregulation on THP1 inflammatory response.CONCLUSION: Our study elucidated the unique involvement of TCN2-driven one-carbon flux on SLE-associated monocyte behavior. Increased TCN2 may promote disease progression and tissue damage by enhancing one-carbon flux, fostering monocyte proliferation and exacerbating TLR4 mediated inflammatory responses. The inhibition of TCN2 may be a promising therapeutic approach to ameliorate SLE.

Project description:Background/Purpose: Systemic lupus erythematosus (SLE) is a complex multi-system autoimmune disease of uncertain etiology. Patients from different ancestral backgrounds demonstrate differences in clinical manifestations and autoantibody profiles. In this study we examined genome-wide transcriptional patterns in major immune cell subsets across different ancestral backgrounds. Methods: Peripheral blood was collected from 21 African-American (AA) and 21 European-American (EA) SLE patients, 5 AA controls, and 5 EA controls. CD4+ T-cells, CD8+ T-cells, monocytes and B cells were purified by flow sorting. Each cell subset from each subject was run on an Illumina HumanHT-12 V4 expression BeadChip array (n=208 arrays). Differentially expressed genes (DEGs) were determined by comparing cases and controls of the same ancestral background. Results: The overlap in DEG lists between different cell types from the same ancestral background was very modest (<1%). Typically between 5-10% of DEGs were shared when comparing the same cell type between different ancestral backgrounds (for ex. CD20 AA vs. CD20 EA). Quantitative measurement of global IFN-stimulated gene (ISG) expression revealed that AA subjects demonstrated more concordance across all studied cell types. Two subgroups of patients were identified based on the ISG expression profiles. One subgroup showed higher ISGs expression in all cell types, and the other subgroup had higherISG expression only in T and B lymphocytes but not in monocytes. The correlation of ISG expression with medication data revealed that only the B cells had lower ISG expression in patients taking immunosuppressants, while ISG expression in the other cell types did not differ based upon medication use. Conclusion: We find striking differences in gene expression between different immune cell subsets and between ancestral backgrounds in SLE patients. The IFN signature is diverse, with different transcripts represented in different cell populations, and signature-positive cell subsets differed in EA vs. AA patients. We also find that treatment with the immunosuppressive agents correlates with the down-regulation of B cell ISG expression, and this was not observed in other cell types.

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Multi-cell type gene co-expression network analysis reveals coordinated interferon response and cross cell-type correlations in systemic lupus erythematosus

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