A novel FLNA p.Pro2469Ser variant is associated with impaired T and NK cell function and immune dysregulation
IMMUNOLOGIC RESEARCH, cilt.74, sa.1, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 74 Sayı: 1
- Basım Tarihi: 2026
- Doi Numarası: 10.1007/s12026-026-09823-w
- Dergi Adı: IMMUNOLOGIC RESEARCH
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, BIOSIS, EMBASE, MEDLINE, Natural Science Collection (ProQuest), Biological Science Database (ProQuest), Biomedical Reference Collection: Corporate Edition (EBSCO), Health Research Premium Collection (ProQuest), Pharma Collection (ProQuest)
- Erciyes Üniversitesi Adresli: Evet
Özet
FLNA encodes filamin A, a ubiquitously expressed actin-binding cytoskeletal protein that cross-links actin filaments and links them to membrane-associated signaling complexes. Although FLNA has been implicated in T-cell signaling and regulatory T-cell development in murine models, its role in human immune-cell function remains incompletely understood. Here, we investigated the immunological phenotype associated with a novel hemizygous FLNA variant identified in a pediatric patient presenting with recurrent infections and inflammatory manifestations. Whole-exome sequencing revealed a hemizygous c.7405C>T (p.Pro2469Ser) variant in FLNA, which was confirmed by Sanger sequencing. Its potential impact on immune-cell function and cytoskeletal organization was evaluated using confocal microscopy, flow cytometry, and molecular assays. Patient-derived T cells showed impaired activation and proliferation following CD3/CD28 and IL-2 stimulation, accompanied by reduced CD25 and CD69 upregulation. CD4+ T cells also exhibited reduced IFN-gamma, TNF-alpha, and IL-2 production after stimulation. Despite elevated basal phospho-STAT5 levels, IL-2-induced STAT5 phosphorylation and TCR-associated signaling responses, including pZAP70, pLCK, and p38 MAPK activation, were attenuated. Confocal imaging together with image-based quantification demonstrated altered cortical cytoskeletal organization in patient T cells despite preserved FLNA expression. In parallel, NK cells showed impaired activation responses and reduced cytotoxic activity under the assay conditions used. Increased apoptosis was observed in CD4(+), CD8(+), and NK-cell populations. Inflammatory cytokines were elevated in plasma and colonic tissue, whereas colonic ZO-1 and FLNA expression were reduced. Collectively, these findings indicate that the FLNA p.Pro2469Ser variant is associated with altered immune-cell signaling, disturbed cortical cytoskeletal organization, and immune dysregulation. This study expands the phenotypic spectrum linked to FLNA variants and supports a role for filamin A in human immune-cell regulation.