RGS5 knockout significantly reduced elevated post-surgery cytokine levels, including IL6 at 4 hours (34.3 vs 62.8 pg/mL, p<0.05), in an atheroprone mouse model subjected to surgical stress.
Does RGS5 knockout reduce the humoral inflammatory response in an atheroprone mouse model under surgical stress?
RGS5 knockout significantly reduces elevated post-surgery cytokine levels in an atheroprone mouse model, suggesting a potential therapeutic target to prevent inflammation-related atherosclerotic cardiovascular events.
Absolute Event Rate: 34.3% vs 62.8%
p-value: p=<0.05
Abstract Background Perioperative myocardial infarction is a deadly complication for a million patients per year worldwide. Cytokines induce atherosclerotic plaque inflammation, thus vulnerability and progression. G-Protein Coupled Receptors (GPCR) and regulators of G-protein signalling, here RGS5, regulate signalling processes contributing to atherosclerosis. Cytokines involved in the inflammatory response to surgery were measured in a model of inducible RGS5 deficiency in atheroprone mice. Purpose To assess the role of RGS5 for the humoral perioperative stress response in vivo. Methods ApoE-/-CreERT2/ERT2RGS5flox/flox mice were fed a high fat diet for 7 weeks. Tamoxifen was administered (2mg ip/d for 5d) to induce RGS5 knockout (KO) before the animals were subjected to a perioperative double-hit (DBH) stress model, combining laparotomy with significant blood loss. Animals were sacrificed at 4- and 72-hours after DBH. RGS5 gene deletion and RNA expression were evaluated by real-time quantitative PCR. Plasma cytokine levels were measured using FACS based multiplex ELISA. Data were analyzed using Wilcoxon test using R in R studio. Results RGS5 DNA copies were reduced to 23% in tamoxifen-induced animals (TaqMan-gDNA-PCR) in bone marrow, leukocytes and spleen (ΔΔCT, mean±SD: 1.03±0.07 vs 0.24±0.12, p0.001). RGS5-mRNA level in spleen was 45% (ΔΔCT: 1.42±1.24 vs 0.78±0.65, p0.05) when compared to untreated controls. Plasma levels of IL6 increased significantly at 4h (median (CI95) in pg/mL, 3.7 (2.95-23.93) vs 62.8 (26.01-130.97), p0.01) and then significantly decreased after 72h (5.5 (2.95-24.08), p0.01) post-surgery. Similarly, CXCL1 levels significantly increased at 4h (in pg/mL, 54.76 (32.45-75.22) vs 124.9 (97.78-257.19), p0.01) and then dropped back to baseline levels at 72h (40.9 (28.58-70.16), p0.01) post DBH. RGS5 KO significantly reduced IL6 at 4h (in pg/mL, 34.3 (13.74-48.76), p0.05) and CXCL1 at 72h (29.6 (19.73-41.20), p0.05). Additionally, RGS5 KO significantly reduced the concentration of CCL11 at 72h (in pg/mL, 745.6 (366.9-964.4) vs 530.6 (259.8-675.3), p0.05) post DBH. Similarly, CCL2 and TNF-α levels were reduced at 72h in Tamoxifen-treated mice. Conclusion RGS5 knockout was efficient with satisfactory penetrance in immune relevant tissues. Elevated post-surgery cytokine levels were significantly reduced by RGS5 KO indicating that lack of RGS5 in immune cells deregulates downstream signaling pathways of GPCRs which hampers cytokine release. RGS5 has a crucial role in immune cell activation and vascular inflammation and further research could deliver potential RGS5-targeted therapeutic strategies to prevent inflammation related atherosclerotic cardiovascular accidents.
Anilkumar et al. (Sat,) conducted a other in Atherosclerosis and perioperative stress. Tamoxifen-induced RGS5 knockout vs. Untreated controls was evaluated on Plasma IL6 levels at 4 hours post-surgery (pg/mL) (p=<0.05). RGS5 knockout significantly reduced elevated post-surgery cytokine levels, including IL6 at 4 hours (34.3 vs 62.8 pg/mL, p<0.05), in an atheroprone mouse model subjected to surgical stress.