A Treatment-Resistant Severe Asthma Phenotype with Dysregulated Hippo Pathway as Shown by Sputum Transcriptomics and Proteomics

Severe asthma is a heterogeneous condition often resistant to conventional corticosteroid therapy, necessitating the identification of novel biomarkers and therapeutic targets. This study investigates immunological, transcriptional, and proteomic biomarkers in severe asthma patients from the Brazilian ProAR cohort. Cytokines were measured using a multiplex technology and the differential sputum cell count was performed by cytospin preparations. Sputum transcriptomics was performed by RNA-seq using Ion S5 next-generation sequencing platform. The proteomic study of sputum was performed by liquid chromatography–tandem mass spectrometry (LC-MS/MS) using Q Exactive Orbitrap technology. Compared to mild-to-moderate asthma (MMA) and treatment-controlled severe asthma (SAC), the treatment-resistant severe asthma (SAR) group exhibited increased sputum neutrophilia, eosinophilia, and elevated IL-6 and TNF levels, correlating with impaired lung function. Transcriptomic and proteomic analyses revealed a Th2-independent molecular signature characterized by downregulation of the Hippo signaling pathway and upregulation of JAK–STAT inflammatory cascades. Distinctive microRNA profiles suggest regulatory involvement in inflammatory and proliferative processes. These findings align with prior studies, reinforcing the presence of an IL-6- and TNF-high severe asthma phenotype across diverse populations. Our results highlight key inflammatory pathways that may underlie corticosteroid resistance, offering potential targets for personalized therapeutic interventions in severe asthma.