Tumour necrosis factor-a (TNFa) is upregulated in inflamed synovium and drives inflammation and pain. Vascular endothelial growth factor-A (VEGF-A) is a family of proteins derived from the vegf-a gene by alternative pre-mRNA splicing. Endogenous control of splicing by activation of serine-arginine-rich protein kinase-1 (SRPK1) increases the expression of pro-angiogenic VEGF-A165a. VEGF-A165a increases adhesion molecule (ICAM-1) expression in normal synoviocytes leading to ICAM-1-dependent inflammatory cell recruitment. We tested the hypotheses that anti-angiogenic, anti-nociceptive VEGF-A165b, or control of VEGF alternative splicing in favour of VEGF-A165b by SRPK1 inhibition would reduce monocyte adherence to human synoviocytes in vitro. Rheumatoid arthritis (RA) and normal human fibroblast-like synoviocytes (HFS, passage 6-12; Sigma) and human THP1 monocytes (passage <30; Sigma) were cultured to confluence. HFS were split into 96 well plates at 12,000 cells/well and incubated for 24h with TNFa 20ng/ml alone or with one of the following: anti-ICAM-1 (100ng/ml); VEGFR inhibitor PTK787 (200nM1); VEGF-A165b (0.01-400ng/mL); SRPK1 inhibitors SRPIN340 (5µM, N-[2-(1-piperidinyl)-5-(trifluoromethyl)phenyl] isonicotinamide, Ascent Scientific, Bristol UK) and SRPIN4 (N-(2-(4-(2-(dimethylamino)ethyl)piperazin-1-yl)-5-(trifluoromethyl) phenyl) isonicotinamide), (5mM, synthesised by JDR and JM, IC50=261nM). After 24h of treatment fluorescein-labelled THP1 cells were added to HFS at 30,000 cells/well, and incubated for 2h, rinsed, and fixed in 4% paraformaldehyde. Relative fluorescence, indicating monocyte adherence to HFS, was quantified on a multi-plate reader. Background fluorescence was subtracted and results normalised to untreated and TNFa treatment alone. Treatment of either RA or normal HFS with TNFa increased fluorescence, which was blocked by co-treatment with anti-ICAM-1. TNFa-induced fluorescence was also significantly reduced by treatment with PTK787 or VEGF-A165b. Inhibitors of SRPK1, SRPIN4 or SRPIN340 significantly reduced fluorescence compared to TNFa treatment (100±19%, n=5 c.f: SRPIN4 49±5%, n=7 p<0.01; SRPIN340, 56±8% n=7; 1-way ANOVA+ Dunnett’s multiple comparison test). Monocyte adherence to TNFa-stimulated normal and RA HFS was dependent on both endogenous VEGF-A/VEGFR and ICAM-1. Inhibiting VEGF receptors with PTK787 or VEGF-A165b significantly prevented monocyte attachment to HFS cells. Results indicate monocyte attachment is mediated by VEGF-A165a and VEGF-A165b may act as a competitive antagonist for VEGF-A165a at VEGFR22. Reduction of monocyte adherence by inhibition of SRPK1 using SRPINs suggests that control of alternative RNA splicing of VEGF may represent an anti-inflammatory strategy.