CHARACTERIZATION OF A MECHANO-IMMUNO-INFLAMMATORY SIGNALING PATHWAY IN RAT HEART PAPILLARY MUSCLES

RACIOPPI, MARÍA FLORENCIA; PEREYRA E; DÍAZ R; GONANO LA; VILA PETROFF M

Capital Federal

Congreso; Reunión anual de la Sociedad Argentina de Fisiología (SAFIS); 2023

Introduction: Sustained mechanical stress leads to adverse cardiac remodeling. It has been shown that mechanical stress triggers an inflammatory response that can damage the heart. However, if axial mechanical stretch induces inflammation has not been fully explored, and the mechanosensors that lead to inflammation in this context have not been examined.Objectives: To determine if mechanical stretch triggers inflammation in papillary muscles and evaluate the mechanosensors involved, in an attempt to describe a novel mechano-immuno-transduction pathway.Methods: Papillary muscles were dissected from left ventricles of male Wistar rats and mounted in a tissue chamber in HEPES buffer. LPS (1μgr/ml) was added to the medium to induce NLRP3 priming. After determining minimum length, one muscle was stretched during the following 2 hours to reach 98% of maximum force development length (STR), while the other remained unstretched (CTR). To evaluate microtubule involvement, the same protocol was performed but in presence of the microtubule inhibitor Colchicine (10 μM). Q-PCR was used to determine expression level of proinflammatory genes TNF-α, IL-1β IL-18 and NLRP3 in muscle samples. Statistical analysis was performed by T Test. Data are expressed as means ± SEM. Differences were considered significant at p ≤ 0.05. Results: A significant increase in TNF-α, IL-18 or NLRP3 gene expression was detected in stretched muscles. This increase was prevented by Colchicine treatment. TNF-α (%ratio of TNF-α /GAPDH mRNA: CTR: 100 ± 11,5(N:6); STR: 333,5 ± 89,5(N:7); CTR+COL: 100 ± 21,7 (N:7); STR+COL: 223,9 ± 65,2 (N:8)). IL18 (%ratio of IL18 /GAPDH mRNA: CTR: 100 ± 18,7(N:7); STR: 330,6 ± 90,5(N:7); CTR+COL: 100 ± 16 (N:8); STR+COL: 197,1 ± 60,4 (N:8)). NLRP3 (%ratio of NLRP3 /GAPDH mRNA: CTR: 100 ± 20.4(N:6); STR: 235,5 ± 48,3(N:7); CTR+COL: 100 ± 15.8 (N:7); STR+COL: 103,5 ± 18,63 (N:7)).Conclusion: Mechanical stretch induces inflammation and the microtubular network is involved in transducing this mechanical stress into the activation of a proinflammatory response.