Journal: bioRxiv

Article Title: cGAS–STING induced IFN-β acts as a dual regulator of osteoclastogenesis via direct and osteoblast-mediated mechanisms

doi: 10.64898/2026.05.09.724040

Figure Lengend Snippet: (A) Effect of cGAS activation by G3-YSD complexed in LyoVec™ (YSD/LV; BMDMs: 250 ng/mL, RAW 264.7: 500 ng/mL) on RANKL-mediated osteoclast formation. Representative images of osteoclasts derived from BMDMs (left) and quantification of relative osteoclast numbers per well in BMDMs and RAW 264.7 cells (right). (B+C) Gene expression analysis of interferon-related genes (B) and osteoclast-associated genes (C) 48 h after stimulation with G3-YSD complexed in LyoVec™ (YSD/LV; BMDMs: 250 ng/mL, RAW 264.7: 500 ng/mL) in the presence or absence of 50 ng/mL RANKL. Data are normalized to the unstimulated control. (D–G) Effect of cGAS inhibition using RU.521 (10 µg/mL in DMSO) on osteoclast formation in RAW 264.7 cells. (D) Quantification of relative osteoclast numbers per well. (E) Gene expression analysis of interferon-related and osteoclast-associated genes 48 h after cGAS inhibition in the presence of 50 ng/mL RANKL. Data are normalized to the unstimulated control. (F) Time-dependent effects of cGAS inhibition, with inhibitor (RU.521, 10 µg/mL in DMSO) added throughout differentiation (“both”), during early stages (first 3 days) or during late stages (days 3–5/6). (G) Pre-inhibition of cGAS by treatment with RU.521 (10 µg/mL in DMSO) 24 h prior to RANKL stimulation. The inhibitor was removed before 50 ng/mL RANKL was added. Left: relative osteoclast numbers per well. Right: gene expression analysis of interferon- and macrophage-related genes and osteoclast-associated genes after 24 h cGAS inhibition followed by 48 h RANKL treatment. Data are normalized to the DMSO pre-treated RANKL control. (A-G) BMDMs were cultured in the presence of 25 ng/mL recombinant mouse M-CSF throughout all experiments. Osteoclast numbers per well are shown relatively to the RANKL control. Heatmaps display mean values, and bar graphs show mean ± SEM with individual data points. Statistical analysis was performed using one-way ANOVA with Bonferroni post hoc test (n = 3). RL: RANKL; LV: LyoVec™ transfection agent.

Article Snippet: Where indicated, cells were treated with: cGAS agonist G3-YSD (RAW 264.7: 500 ng/mL; BMDMs: 250 ng/mL) complexed with LyoVecTM (1:100, 15 min pre-incubation), cGAS inhibitor RU.521 (10 μg/mL in DMSO) added 3 h prior to stimulation; STING agonists 2′3′-cGAMP (RAW: 10 μg/mL; BMDMs: 5 μg/mL) or diABZI (0.01–10 μg/mL), STING inhibitor H-151 (40 or 400 ng/mL in DMSO) added 2 h prior to stimulation (all InvivoGen, USA).

Techniques: Activation Assay, Derivative Assay, Gene Expression, Control, Inhibition, Cell Culture, Recombinant, Transfection

Journal: bioRxiv

Article Title: cGAS–STING induced IFN-β acts as a dual regulator of osteoclastogenesis via direct and osteoblast-mediated mechanisms

doi: 10.64898/2026.05.09.724040

Figure Lengend Snippet: (A) Gene expression analysis of osteoblasts after stimulation with cGAS–STING agonists for 24 h (G3-YSD: 500 ng/mL, 2’3’-cGAMP: 5 µg/mL, diABZI: 500 ng/mL). Left: heatmap of cGAS–STING pathway-associated genes, including Tnfsf11 (RANKL) and Tnfrsf11b (OPG). Right: ratio of Tnfrsf11b to Tnfsf11 mRNA levels. Data are normalized to the unstimulated control. (B) Protein concentrations of IFN-β and OPG in supernatants of osteoblasts after 24 h stimulation with cGAS–STING agonists (G3-YSD: 500 ng/mL, 2’3’-cGAMP: 5 µg/mL, diABZI: 500 ng/mL). (C) Co-culture model with osteoblasts seeded in the lower compartment and pre-stimulated with cGAS–STING agonists for 24 h (G3-YSD: 500 ng/mL, 2’3’-cGAMP: 5 µg/mL, diABZI: 500 ng/mL), followed by co-culture with strain-matched BMDMs in transwell inserts and induction of osteoclastogenesis using 25 ng/mL M-CSF and 50 ng/mL RANKL. Osteoclast formation was assessed by TRAP staining. Left: representative images of osteoclasts. Middle: images of transwell inserts after TRAP staining. Right: quantification of osteoclast numbers per transwell. (D) Immunoblot analysis of RUNX2 protein levels and IRF3 pathway activation, indicated by phosphorylated IRF3, in osteoblasts after 3 h of cGAS– STING stimulation (G3-YSD: 500 ng/mL, 2’3’-cGAMP: 5 µg/mL, diABZI: 500 ng/mL). HSP90 served as a loading control. (E) Gene expression analysis of osteoblasts after stimulation with STING agonists for 6 h (2’3’-cGAMP: 5 µg/mL, diABZI: 500 ng/mL). Heatmap and OPG–RANKL ratio are presented as described in (B). (F) Co-culture model as described in (C), with osteoblasts pre-stimulated with STING agonists (2’3’-cGAMP: 5 µg/mL, diABZI: 500 ng/mL) for 3 h prior to co-culture with BMDMs. (A-F) Osteoclast numbers per well are shown relatively to the unstimulated osteoblast control. Heatmaps display mean values, and bar graphs show mean ± SEM with individual data points. Statistical analysis was performed using one-way ANOVA with Bonferroni post hoc test (n = 3). OB: osteoblast; OC: osteoclast; Mϕ: macrophage; LV: LyoVec™ transfection agent.

Article Snippet: Where indicated, cells were treated with: cGAS agonist G3-YSD (RAW 264.7: 500 ng/mL; BMDMs: 250 ng/mL) complexed with LyoVecTM (1:100, 15 min pre-incubation), cGAS inhibitor RU.521 (10 μg/mL in DMSO) added 3 h prior to stimulation; STING agonists 2′3′-cGAMP (RAW: 10 μg/mL; BMDMs: 5 μg/mL) or diABZI (0.01–10 μg/mL), STING inhibitor H-151 (40 or 400 ng/mL in DMSO) added 2 h prior to stimulation (all InvivoGen, USA).

Techniques: Gene Expression, Control, Co-Culture Assay, Staining, Western Blot, Activation Assay, Transfection

Journal: bioRxiv

Article Title: cGAS–STING induced IFN-β acts as a dual regulator of osteoclastogenesis via direct and osteoblast-mediated mechanisms

doi: 10.64898/2026.05.09.724040

Figure Lengend Snippet: (A) Effect of cGAS activation by G3-YSD complexed in LyoVec™ (YSD/LV; BMDMs: 250 ng/mL, RAW 264.7: 500 ng/mL) on RANKL-mediated osteoclast formation. Representative images of osteoclasts derived from BMDMs (left) and quantification of relative osteoclast numbers per well in BMDMs and RAW 264.7 cells (right). (B+C) Gene expression analysis of interferon-related genes (B) and osteoclast-associated genes (C) 48 h after stimulation with G3-YSD complexed in LyoVec™ (YSD/LV; BMDMs: 250 ng/mL, RAW 264.7: 500 ng/mL) in the presence or absence of 50 ng/mL RANKL. Data are normalized to the unstimulated control. (D–G) Effect of cGAS inhibition using RU.521 (10 µg/mL in DMSO) on osteoclast formation in RAW 264.7 cells. (D) Quantification of relative osteoclast numbers per well. (E) Gene expression analysis of interferon-related and osteoclast-associated genes 48 h after cGAS inhibition in the presence of 50 ng/mL RANKL. Data are normalized to the unstimulated control. (F) Time-dependent effects of cGAS inhibition, with inhibitor (RU.521, 10 µg/mL in DMSO) added throughout differentiation (“both”), during early stages (first 3 days) or during late stages (days 3–5/6). (G) Pre-inhibition of cGAS by treatment with RU.521 (10 µg/mL in DMSO) 24 h prior to RANKL stimulation. The inhibitor was removed before 50 ng/mL RANKL was added. Left: relative osteoclast numbers per well. Right: gene expression analysis of interferon- and macrophage-related genes and osteoclast-associated genes after 24 h cGAS inhibition followed by 48 h RANKL treatment. Data are normalized to the DMSO pre-treated RANKL control. (A-G) BMDMs were cultured in the presence of 25 ng/mL recombinant mouse M-CSF throughout all experiments. Osteoclast numbers per well are shown relatively to the RANKL control. Heatmaps display mean values, and bar graphs show mean ± SEM with individual data points. Statistical analysis was performed using one-way ANOVA with Bonferroni post hoc test (n = 3). RL: RANKL; LV: LyoVec™ transfection agent.

Article Snippet: Where indicated, cells were treated with: cGAS agonist G3-YSD (RAW 264.7: 500 ng/mL; BMDMs: 250 ng/mL) complexed with LyoVecTM (1:100, 15 min pre-incubation), cGAS inhibitor RU.521 (10 μg/mL in DMSO) added 3 h prior to stimulation; STING agonists 2′3′-cGAMP (RAW: 10 μg/mL; BMDMs: 5 μg/mL) or diABZI (0.01–10 μg/mL), STING inhibitor H-151 (40 or 400 ng/mL in DMSO) added 2 h prior to stimulation (all InvivoGen, USA).

Techniques: Activation Assay, Derivative Assay, Gene Expression, Control, Inhibition, Cell Culture, Recombinant, Transfection