Long non-coding RNAs in thoracic aortic aneurysm - pathophysiological investigations and clinical implications

• Applicant: Dr. Joscha Büch
• Subject Area: Cardiac and Vascular Surgery
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 545858507

The thoracic aortic aneurysm is associated with a high mortality rate, mainly due to ruptures and dissections. Pathophysiologically, there is a degeneration of vascular smooth muscle cells (VSMC). Current studies suggest that long non-coding RNAs (lncRNA) may play a regulatory role in this process. Preliminary Data from single-cell RNA sequencing of thoracic aortic aneurysms identified the lncRNAs TMEM72-AS1 and LINC00632, which show a specific expression in VSMC. Quantitative expression analyses revealed that both lncRNAs are significantly upregulated in dilated compared to non-dilated areas. A temporary siRNA-mediated knock-out in primary VSMC further resulted in apoptosis activation and reduced migration and proliferation. In the planned research projects, these two lncRNAs will now be further studied in the context of thoracic aortic aneurysm. This will be done in three larger work packages: 1. Expression of TMEM72-AS1 and LINC00632 in blood: qPCR will be used to examine whether the lncRNAs potentially serve as biomarkers. This involves comparing the expression in blood samples from patients with and without an aortic aneurysm. 2. Fluorescence-based localization study: Using in situ hybridization techniques such as RNAscope® or FISH, the precise localization of TMEM72-AS1 and LINC00632 within the cell structure will be visualized. 3. Functional analysis of lncRNA in the "Aorta-on-a-chip" (AoOC) model: The AoOC assay is a two-layered 3D cell culture model simulating a vascular wall, mimicking the behavior of the cell structure in vivo. Primary endothelial cells and VSMC are separated by a porous membrane representing the basement membrane, maintaining cell-to-cell communication. The membrane is placed in a chip connected to a micro-pump system integrated into an incubator, subjecting the cells to physiological shear stress. The impact of pathophysiological situations on the expression of TMEM72-AS1 and LNC00632 will be analyzed by fluoreszenz based assays and qPCR. Furthermore, the effects of siRNA-mediated inhibition and lentiviral overexpression of the lncRNAs on the cell structure will be investigated. The results of the project may contribute to a deeper understanding of the pathophysiology of thoracic aortic aneurysm and in particular of the lncRNAs TMEM72-AS1 and LINC00632.

• DFG Programme: WBP Fellowship
• International Connection: Sweden
• Hosts: Professor Dr. Lars Mägdefessel; Professor Dr. Peder S. Olofsson