Circadian regulation of neutrophil-driven morning stiffness in rheumatoid arthritis

The National Institute of Allergy and Infectious Diseases awarded Weill Medical College of Cornell University $110,228 on November 28, 2026, under the Allergy and Infectious Diseases Research program (CFDA 93.855, Project Grant F30AI200263).

The award funds research into circadian regulation of neutrophil-driven morning stiffness in rheumatoid arthritis. The three-aim study will identify immune signatures in blood associated with morning stiffness through RNA sequencing of longitudinal blood samples, patient-reported symptom tracking, and computational deconvolution of cell-type-specific gene expression. A second aim will define joint-specific inflammatory activity by comparing transcriptomic profiles of matched blood and synovial fluid from rheumatoid arthritis patients with morning stiffness, with further analysis through neutrophil-focused functional assays including netosis and activation studies. The third aim will investigate how synovial endothelial cells regulate immune cell entry into joints using CITE-SEQ data from previously collected rheumatoid arthritis patient synovial tissue and co-culture assays with primary human cells to test endothelial cell recruitment of neutrophils.

Work is performed at Weill Medical College of Cornell University in New York, New York. The period of performance runs through June 30, 2030.

Abstract

Rheumatoid arthritis (RA) is a systemic autoimmune disease that targets synovial joints, leading to pain, stiffness, and disability. One of its most debilitating and poorly understood symptoms is morning stiffness, a prolonged period of joint immobility after waking that significantly impairs mobility and quality of life. These symptoms follow consistent daily patterns, suggesting that time-of-day variation in immune activity contributes to joint inflammation. However, the molecular mechanisms linking systemic immune rhythms to joint-specific disease remain unknown. This proposal tests the central hypothesis that circadian immune dynamics shape the timing and localization of joint inflammation in RA through interactions with synovial endothelial and tissue-specific programs. Aim 1 will identify immune signatures in blood associated with morning stiffness by integrating RNA sequencing of longitudinal blood samples, patient-reported symptom tracking, and computational deconvolution of cell type- specific gene expression. Aim 2 will define joint-specific inflammatory activity by comparing transcriptomic profiles of matched blood and synovial fluid from RA patients with morning stiffness. These samples will be further analyzed through neutrophil-focused functional assays, including netosis and activation studies. Aim 3 will investigate how synovial endothelial cells regulate immune cell entry into joints, helping to explain why some joints show more pronounced diurnal symptom patterns compared to others nearby. We will analyze endothelial cell states using cite-SEQ data from previously collected RA patient synovial tissue (AMP phase 2) and test their ability to recruit neutrophils in CO-culture assays with primary human cells. This work will establish a new framework for understanding how systemic immune rhythms interact with joint- specific cues to drive spatial and temporal variation in autoimmune disease. Insights from this research may inform time-based biomarker strategies and help explain heterogeneity in RA severity across patients and joints. Training will be conducted in the TRI-institutional MD-PHD program under the guidance of a multidisciplinary mentorship team with expertise in immunology, transcriptomics, and translational rheumatology.