Role of vascular smooth muscle Interleukin-11 in aortic aneurysm development

BACKGROUND: The formation of aortic aneurysms (AAs) presents a significant cardiovascular risk, with limited treatment options. Our laboratory examined wild-type (WT) and BCL11B knockout (BSMKO) mice treated with Angiotensin II (AngII) for a period of 7 days. The BSMKO mice given AngII exhibited aneurysm formation, while the WT mice did not show this response. RNA sequencing of entire aortas from BSMKO mice and WT mice given this AngII treatment revealed that Interleukin-11 (IL-11) was the most significantly increased in BSMKO aortas compared to the WT aortas. This research aims to validate these findings in vascular smooth muscle cells (VSMCs) and identify the molecular pathways connecting the knockout of BCL11B to IL-11 expression and AA development via AT1 receptors and PIEZO1 channels. METHODS: To simulate these BSMKO conditions, aortic VSMCs were pharmacologically treated with AngII and Yoda1. This treatment is expected to enhance calcium influx via AT1 receptors and PIEZO1 channels, resulting in increased activity of the calcium-dependent phosphatase calcineurin (PP2B). PP2B then dephosphorylates the inactive, phosphorylated nuclear factor of activated T-cells (NFAT), facilitating the activation and nuclear translocation of NFAT2, which may promote IL-11 transcription. Western blot analysis was performed to assess IL-11 and NFAT2 levels in VSMCs after exposure to AngII (100 μM), Yoda1 (20 μM), and their combination over 24 hours. IL-11 and NFAT2 expression levels were analyzed using ImageJ. RESULTS: Western blot analysis revealed that AngII treatment alone resulted in variable IL-11 expression, with some instances of upregulation and others where no significant increase was observed (n=6; p = 0.9226) compared to control. Yoda1 treatment led to a slight, non-significant increase in IL-11 levels (n=4; p = 0.0896). However, co-treatment with AngII and Yoda1 consistently produced the highest IL-11 expression, showing a statistically significant increase compared to the control (n=3; p = 0.0162). Additionally, Western blot analysis indicated an upregulation of NFAT2 in all treatment conditions compared to control, suggesting that AngII and PIEZO1 activation triggered calcium-related events culminating in NFAT2 activation, consistent with our hypothesis. CONCLUSION: Our results suggest that calcium entry through AT1 receptors and PIEZO1 channels enhances IL-11 expression in VSMCs, potentially via the calcium-dependent PP2B/NFAT2 pathway. By linking mechanosensitive calcium signaling to IL-11 expression, which has been linked to apoptosis or inflammation of VSMCs, this research offers new insights into the underlying molecular mechanisms of AA formation. Future research should explore whether targeting PIEZO1, AT1 receptors, or PP2B/NFAT2 signaling could serve as a therapeutic strategy to prevent AAs.

Author dc:creator

• Alton, Bardayson Karim

Advisors dc:contributor.advisor

• Seta, Francesca
• Herscovitz, Haya

• Biology

Language dc:language.iso

en_US

Handle dc:identifier.uri

https://hdl.handle.net/2144/52228

OAI identifier oai:identifier

oai:open.bu.edu:2144/52228