Rheumatoid arthritis (RA) is a systemic autoimmune disorder characterized by chronic synovitis and progressive joint destruction. Fibroblast-like synoviocytes (FLS) are pivotal drivers of this pathology, exhibiting tumor-like proliferation, invasiveness, and robust secretion of inflammatory mediators. GATA6, a transcription factor critical in development, has recently been implicated in fibrotic diseases, however, its functional significance in RA-FLS has not been explored.

To investigate the expression, function, and molecular mechanism of GATA6 in regulating the pathogenic phenotype of RA-FLS.

Overexpression (LV-GATA6) and knockdown (LV-GATA6-shRNA) lentiviral vectors targeting GATA6 were constructed. The effect of GATA6 modulation on FLS proliferation and migration was evaluated using CCK-8 and Transwell assays, respectively. The impact of GATA6 on the secretory profile of FLS was determined by quantifying mRNA and protein levels of interleukin-6 (IL-6), RANKL, fibronectin (FN), cadherin-11 (CDH-11), matrix metalloproteinase-1 (MMP-1), and matrix metalloproteinase-13 (MMP-13) via RT-qPCR and Western blot analysis.

MH7A cells were divided into three experimental groups: control, GATA6-overexpressing, and GATA6-silenced. GATA6 overexpression significantly enhanced the proliferation and migration of MH7A cells, while its knockdown markedly reduced both processes (p < 0.05). Paradoxically, silencing GATA6 led to a significant upregulation of IL-6, RANKL, CDH-11, MMP-1, and MMP-13, accompanied by a significant reduction in FN expression (p < 0.05).

In summary, this study is the first to systematically identify the transcription factor GATA6 as a critical regulator of fibroblast-like synoviocyte (FLS) function in rheumatoid arthritis (RA). Our findings demonstrate that GATA6 not only promotes FLS proliferation and migration but also exerts intricate, bidirectional control over a network of key pathogenic effectors, including IL-6, RANKL, CDH-11, MMPs, and fibronectin. This regulatory complexity positions GATA6 as a dynamic molecular hub that integrates microenvironmental signals to fine-tune FLS activation and tissue-destructive potential, rather than functioning as a simple linear switch.

Based on these observations, we propose a novel "stage-dependent dual role" hypothesis for GATA6 in RA pathogenesis. In this model, GATA6 may drive synovial hyperplasia in early disease stages, while its subsequent dysregulation—particularly its downregulation—could unleash a destructive program characterized by enhanced FLS aggregation (via CDH-11) and matrix degradation (via MMPs), thereby contributing to irreversible joint damage. This framework challenges the conventional view of pathogenic factors as uniformly pro-inflammatory and offers a new lens through which to understand the complex and often contradictory dynamics of synovial pathology.

By revealing this previously unrecognized layer of transcriptional control, our work provides new insights into the mechanisms of FLS activation and positions GATA6 and its downstream network as potential therapeutic targets. However, given its context-dependent functions, therapeutic strategies must be approached with caution. Future investigations should focus on elucidating the precise molecular mechanisms governing GATA6's bidirectional activity, validating its role in *in vivo* arthritis models using cell-type-specific genetic approaches, and exploring its clinical relevance in patient cohorts. Such efforts will be essential to determine whether targeting GATA6—or specific nodes within its regulatory network—can be translated into safe and effective therapies for RA.