Molecular endotypes of type 1 and type 2 SLE

Area of Science:

• Immunology
• Genomics
• Systems Biology

Background:

• Systemic lupus erythematosus (SLE) is a complex autoimmune disease with heterogeneous clinical presentations.
• Distinguishing between different SLE subtypes, such as type 1 and type 2 SLE, is crucial for targeted treatment and understanding disease pathogenesis.
• Gene expression profiling offers a powerful tool to explore the molecular underpinnings of disease heterogeneity.

Purpose of the Study:

• To characterize the distinct molecular landscapes of type 1 and type 2 SLE by analyzing peripheral blood gene expression profiles.
• To identify unique transcriptional patterns that differentiate between type 1 and type 2 SLE.
• To correlate molecular signatures with clinical features and identify potential biomarkers for disease subtypes and severity.

Main Methods:

• Transcriptomic RNA sequencing was performed on whole blood samples from 18 SLE patients.
• Multiscale Embedded Gene Co-expression Network Analysis (MECoN) was applied to the top 5000 variable genes.
• Gene co-expression modules were functionally annotated and correlated with demographic, clinical, and laboratory data.

Main Results:

• Specific gene co-expression modules significantly correlated with individual features of type 1 and type 2 SLE.
• These modules effectively segregated samples from type 1 SLE patients from those with type 2 SLE.
• Type 1 SLE showed enrichment in interferon, monocyte, T cell, cell cycle, and neurotransmitter pathways, while type 2 SLE was enriched in B cell, metabolic, and neuromuscular pathways.
• Type 2 SLE modules were also identified in patients with inactive SLE, idiopathic fibromyalgia, and active SLE with severe fatigue.

Conclusions:

• Gene co-expression analysis successfully identified unique transcriptional patterns that distinguish type 1 SLE from type 2 SLE.
• The study elucidated distinct molecular features associated with each SLE subtype.
• These findings highlight the potential of molecular profiling to identify type 2 SLE characteristics in patients with inactive disease, fibromyalgia, or severe fatigue.