The role of phosphoinositide 3-kinases in immune-inflammatory responses: potential therapeutic targets for abdominal aortic aneurysm

The Molecular Mechanisms of Bergapten Against Abdominal Aortic Aneurysm: Evidence From Network Pharmacology, Molecular Docking/Dynamics, and Experimental Validation

This study endeavors to assess the potential protective role of bergapten (BP) in mitigating abdominal aortic aneurysm (AAA) and to decipher the underlying mechanisms and molecular targets. Network pharmacology was utilized to search for potential targets of BP against AAA. Molecular docking and molecular dynamics simulations were utilized to validate the interaction of BP with core targets, and then the therapeutic effect and mechanism of BP on AAA were verified by using an elastase-induced AAA model. Network pharmacology analysis identified five pharmacological targets for BP, including EGFR, SRC, PIK3CA, PIK3CB, and JAK2. Molecular docking and molecular dynamics simulations further prioritized JAK2 as the most promising candidate for the potential treatment of AAA. The results of animal experiments demonstrated that BP significantly reduced the expression of inflammatory cytokines IL-6, TNF-α, and IL-1β in the aortic tissue of AAA mouse model, and inhibited the phosphorylation of JAK2 and STAT3. BP plays an important role in the treatment of AAA, and it may become a promising drug to combat AAA progression. The inhibitory effect of BP on AAA vascular progression and the attenuation of inflammatory cell infiltration may be related to the regulation of JAK2/STAT3 signaling pathway.

Prenyl diphosphate synthase subunit 2 is downregulated in abdominal aortic aneurysm and retards the progression of abdominal aortic aneurysm

Objective

Abdominal aortic aneurysm (AAA) is a complex and fatal vascular disease for which specific treatments are still lacking. This study explored the effect and possible mechanisms of prenyl diphosphate synthase subunit 2 (PDSS2) on angiotensin II (Ang II)-induced AAA in human vascular smooth muscle cells (VSMCs).

Material and Methods

The AAA cell model was established by treating VSMCs with 1 μM Ang II for 24 h. The effect of Ang II on VSMC viability was detected by cell counting kit-8 assay. The role of PDSS2 on VSMC proliferation was examined using the 5-ethynyl-2'-deoxyuridine method. The influence of Ang II and PDSS2 on VSMC apoptosis was analyzed by flow cytometry. The expression changes of PDSS2, apoptosis-related proteins, and phosphatidylinositol 3 kinase/protein kinase B/mechanistic target of rapamycin (PI3K/AKT/mTOR) pathway-related proteins were detected by Western blot analysis.

Results

After treatment with Ang II, the VSMCs showed decreased viability and increased apoptosis (P < 0.01). PDSS2 expression was low in the AAA tissues and Ang II-treated VSMCs (P < 0.01). PDSS2 promoted the proliferation and blocked the apoptosis of Ang II-treated VSMCs, and si-PDSS2 showed the opposite effect (P < 0.01). PDSS2 also decreased the levels of p-mTOR, p-AKT, and p-PI3K, which, in turn, were increased by si-PDSS2 (P < 0.01).

Conclusion

PDSS2 was downregulated in AAA and retarded the progression of VSMCs partially through the PI3K/AKT/mTOR pathway. This work explored the molecular mechanism of PDSS2 in the prevention, diagnosis, and treatment of AAA.

Mesenchymal stem cell-derived extracellular vesicles protect against abdominal aortic aneurysm formation by inhibiting NET-induced ferroptosis

Neutrophil extracellular traps (NETs) play an important role in abdominal aortic aneurysm (AAA) formation; however, the underlying molecular mechanisms remain unclear. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) may exert therapeutic effects on AAA through their immunomodulatory and regenerative abilities. This study aimed to examine the role and mechanism of MSC-EVs in regulating the development of NET-mediated AAA. Excessive release of NETs was observed in patients with AAA, and the levels of NET components were associated with the clinical outcomes of the patients. Datasets from the Gene Expression Omnibus database were analyzed and revealed that the PI3K/AKT pathway and ferroptosis were strongly associated with NETosis during AAA formation. Further experiments verified that NETs promoted AAA formation by inducing ferroptosis in smooth muscle cells (SMCs) by inhibiting the PI3K/AKT pathway. The PI3K agonist 740 Y-P, the ferroptosis inhibitor ferrostatin-1, and Padi4 deficiency significantly prevented AAA formation. MSC-EVs attenuated AAA formation by reducing NET release in an angiotensin II-induced AAA mouse model. In vitro experiments revealed that MSC-EVs reduced the release of NETs by shifting NETosis to apoptosis. Our study indicates an important role for NET-induced SMC ferroptosis in AAA formation and provides several potential targets for AAA treatment.

HDL metabolism and functions impacting on cell cholesterol homeostasis are specifically altered in patients with abdominal aortic aneurysm

Background

The etiopathogenesis of abdominal aortic aneurysm (AAA) is still unclarified, but vascular inflammation and matrix metalloproteases activation have a recognized role in AAA development and progression. Circulating lipoproteins are involved in tissue inflammation and repair, particularly through the regulation of intracellular cholesterol, whose excess is associated to cell damage and proinflammatory activation. We analyzed lipoprotein metabolism and function in AAA and in control vasculopathic patients, to highlight possible non-atherosclerosis-related, specific abnormalities.

Methods

We measured fluorometrically serum esterified/total cholesterol ratio, as an index of lecithin-cholesterol acyltransferase (LCAT) activity, and cholesteryl ester transfer protein (CETP) activity in patients referred to vascular surgery either for AAA (n=30) or stenotic aortic/peripheral atherosclerosis (n=21) having similar burden of cardiovascular risk factors and disease. We measured high-density lipoprotein (HDL)-cholesterol efflux capacity (CEC), through the ATP-binding cassette G1 (ABCG1) and A1 (ABCA1) pathways and serum cell cholesterol loading capacity (CLC), by radioisotopic and fluorimetric methods, respectively.

Results

We found higher LCAT (+23%; p &lt; 0.0001) and CETP (+49%; p &lt; 0.0001) activity in AAA sera. HDL ABCG1-CEC was lower (−16%; p &lt; 0.001) and ABCA1-CEC was higher (+31.7%; p &lt; 0.0001) in AAA. Stratification suggests that smoking may partly contribute to these modifications. CEC and CETP activity correlated with CLC only in AAA.

Conclusions

We demonstrated that compared to patients with stenotic atherosclerosis, patients with AAA had altered HDL metabolism and functions involved in their anti-inflammatory and tissue repair activity, particularly through the ABCG1-related intracellular signaling. Clarifying the relevance of this mechanism for AAA evolution might help in developing new diagnostic parameters and therapeutic targets for the early management of this condition.