# Genetic Pleiotropy and Causal Pathways Linking Glycemic Traits to Asthma: An Integrated Proteogenomic Investigation

## TL;DR

This study finds that obesity and type 2 diabetes share genetic links with asthma, suggesting that targeting shared inflammatory proteins could help treat both conditions.

## Contribution

The study identifies specific shared genetic loci and proteins linking metabolic traits with asthma, revealing novel therapeutic targets.

## Key findings

- Obesity and type 2 diabetes have significant genetic correlations with asthma.
- Shared pleiotropic loci and proteins like IL6R, MAPK3, and CSF2 connect diabetes and asthma through inflammatory pathways.
- Targeting JAK-STAT signaling may offer new treatments for comorbid diabetes and asthma.

## Abstract

What are the main findings?
Obesity (BMI) and type 2 diabetes mellitus (T2DM) show significant genetic correlations and causal effects on asthma risk.Shared pleiotropic loci and key proteins (e.g., IL6R, MAPK3, CSF2) link diabetes/glycemic traits with asthma through inflammatory pathways.

Obesity (BMI) and type 2 diabetes mellitus (T2DM) show significant genetic correlations and causal effects on asthma risk.

Shared pleiotropic loci and key proteins (e.g., IL6R, MAPK3, CSF2) link diabetes/glycemic traits with asthma through inflammatory pathways.

What is the implication of the main finding?
These findings suggest that metabolic dysfunction contributes to asthma pathogenesis via shared genetic and immunological mechanisms.Targeting colocalized proteins and pathways such as JAK-STAT signaling may provide novel therapeutic strategies for comorbid diabetes and asthma.

These findings suggest that metabolic dysfunction contributes to asthma pathogenesis via shared genetic and immunological mechanisms.

Targeting colocalized proteins and pathways such as JAK-STAT signaling may provide novel therapeutic strategies for comorbid diabetes and asthma.

Background: While diabetes is a recognized risk factor for asthma, the shared genetic components between diabetes/glycemic traits and asthma remain unclear. This study investigates the genetic associations, causal relationships, and underlying mechanisms linking these conditions. Methods: We assessed global genetic correlations using linkage disequilibrium score regression (LDSC), high-definition likelihood analysis (HDL), and genetic covariance analysis (GNOVA). Trait pairs with significant correlations subsequently underwent genetic overlap analysis (Genetic analysis integrating Pleiotropy and functional Annotation, GPA) and local genetic correlation analysis (Local Genetic Variant Association Analysis, LAVA). Cross-phenotype association (CPASSOC) and multitrait analysis of GWAS (MTAG) identified potential pleiotropic loci, followed by colocalization and functional annotation. Proteome-wide association study (PWAS) revealed proteins and pathways shared between diabetes/glycemic traits and asthma. Generalized summary-data-based Mendelian randomization (GSMR) was used to evaluate causal effects between diabetes/glycemic traits and asthma. Results: Significant genetic correlations were observed between body mass index (BMI) and asthma (rg = 0.280–0.397; FDR < 0.05), type 2 diabetes mellitus (T2DM) and asthma (rg = 0.240–0.289; FDR < 0.05) across all three methods. GPA revealed significant genome-wide genetic overlap, highest for BMI and asthma (pleiotropy association ratio [PAR] = 0.377) and T2DM-asthma (PAR = 0.353). LAVA identified 111 significant local correlation regions, predominantly between T2DM and asthma (70 regions). Colocalization analysis identified 24 shared pleiotropic loci, predominantly on chromosome 8. Local genetic correlation analysis revealed extensive correlations between T2DM and asthma. PWAS identified 46 shared proteins, with IL6R, MAPK3, and CSF2 being key hubs. Protein–protein interaction analysis highlighted enrichment in JAK-STAT signaling, Th1/Th2 differentiation, and IL-17 pathways. GSMR demonstrated causal effects of BMI (OR = 1.47, 95% CI: 1.42–1.53, FDR < 0.05) and T2DM (OR = 1.06, 95% CI: 1.04–1.08, FDR < 0.05) on increased asthma risk, with no evidence of reverse causality. Conclusions: Obesity (BMI) and T2DM exert causal effects on asthma risk via shared genetic loci and inflammatory pathways, particularly involving IL6R, MAPK3, CSF2, and JAK-STAT signaling. Targeting these colocalized proteins may offer potential therapeutic strategies.