Abstract Body (Do not enter title and authors here): Background
Marfan syndrome (MFS) is a heritable autosomal dominant multisystem disorder of connective tissues caused by variants in FBN1 gene, which encodes fibrillin-1, a major component of microfibrils in extracellular matrix. Most premature deaths are related to thoracic aortic aneurysm that grows and progresses to catastrophic aortic rupture or dissection without prior symptoms. Previous reports showed that intraperitoneal injections with transforming growth factor (TGF)-β neutralizing antibodies mitigated aortic aneurysm formation in MFS (Fbn1^C1041G/+) mice. However clinical application in MFS patients has not yet been achieved. Recent research on vaccination has extended its scope from infectious diseases to chronic diseases, including hypertension and dyslipidemia. The aim of this study is to design a TGF-β vaccine for prevention of aortic aneurysm in MFS mice.
Methods
We created TGF-β vaccines (vaccine A and B) by mixing a peptide that recognizes the two amino acid sequences (p.304-313 and p.313-322), common to human and mouse TGF-β1 as antigens with a carrier protein and an adjuvant. We injected subcutaneously two candidate vaccines to C57BL/6J background Fbn1^+/+ mice and antibody titers were measured using ELISA. The vaccine with higher titers was selected from two candidate vaccines, and TGF-β vaccine and control vaccine were injected subcutaneously twice at two-week intervals, followed by a third injection one week later, for a total of three injections in 4-week-old male Fbn1^+/+ and Fbn1^C1041G/+ mice.
Results
Significant increase in antibody titers was observed in the serum of TGF-β vaccines-injected Fbn1^+/+ mice for both vaccine A and B. However, ELISA using recombinant TGF-β1 as antigen showed a significant increase in antibody titer only in vaccine A. In 16-week-old TGF-β vaccine A-injected Fbn1^C1041G/+ mice, the enlargement of aortic diameter was significantly suppressed, as compared with control vaccine-injected Fbn1^C1041G/+ mice. Histologically, aortic wall thickening with degeneration of elastic fibers and proteoglycan deposition and downstream signaling of the TGF-β pathway were attenuated in ascending aorta of TGF-β vaccine A-injected Fbn1^C1041G/+ mice. No inflammatory cell infiltration was observed in any of the organs, including the heart, kidneys, and liver in the TGF-β vaccine A-injected group.
Conclusion
Our findings support that the TGF-β vaccine could be a novel therapeutic agent for suppressing aortic aneurysm progression in MFS.