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Exogenous spermine inhibits high glucose/oxidized LDL-induced oxidative stress and macrophage pyroptosis by
Yuxuan Qiu1, Linna Li2, Xiaohui Guo2
1Department of Endocrinology and Metabolic Disease, Harbin Medical University, Harbin, Heilongjiang 150076, P.R. China.
Abstract:
Evidence suggests that macrophage pyroptosis promotes the progression of diabetic atherosclerosis. Spermine, a natural cellular metabolite, demonstrates a protective effect against cardiovascular diseases. However, whether spermine has a protective effect against macrophage pyroptosis caused by high glucose (HG) and oxidized low-density lipoprotein (ox-LDL) conditions remains to be elucidated. To investigate the protective effect of spermine and the related underlying mechanism, THP-1 macrophages were treated with HG/ox-LDL, spermine, or the specific nuclear factor erythroid 2-related factor 2 (Nrf2) inhibitor ML385. Cell viability was detected using CCK-8, cell membrane permeability was analyzed using lactate dehydrogenase (LDH) and Hoechst/propidium iodide staining and pyroptosis-related gene and protein expression levels were evaluated using polymerase chain reaction and western blot analysis. Spermine showed a potent preventive effect on THP-1 macrophage pyroptosis and oxidative stress induced by HG/ox-LDL. Cells treated with spermine showed increased cell viability, reduced reactive oxygen species (ROS) production, decreased LDH levels in the supernatant and reduced cell swelling. In addition, spermine significantly reduced NLR family pyrin domain containing 3, cleaved caspase-1, N-gasdermin D and IL-1β expression, as well as IL-1β levels in the supernatant. This demonstrated that the inhibition of pyroptosis and oxidative stress due to spermine was Nrf2 dependent. Furthermore, spermine enhanced Nrf2 nuclear translocation, thereby increasing heme oxygenase-1 and NADPH quinone oxidoreductase-1 expression, which subsequently reduced ROS production. In addition, the anti-pyroptotic and antioxidant effects of spermine were reversed by ML385 inhibition of Nrf2. It was concluded that spermine prevented macrophage pyroptosis and increased ROS overproduction by activating the Nrf2 pathway. The data suggested that spermine may be a potential novel drug for the treatment of diabetic atherosclerosis because it targets macrophage pyroptosis.
Insights
Spermine prevents cell damage and pyroptosis in macrophages under high glucose and oxidized LDL conditions. This protective effect against diabetic atherosclerosis is mediated by activating the Nrf2 pathway, reducing oxidative stress.
Area of Science:
- Biochemistry
- Cell Biology
- Cardiovascular Research
Background:
- Macrophage pyroptosis is implicated in diabetic atherosclerosis progression.
- Spermine, a natural metabolite, shows cardiovascular benefits.
- The effect of spermine on high glucose/oxidized LDL-induced macrophage pyroptosis is unknown.
Purpose of the Study:
- To investigate the protective effect of spermine against high glucose/oxidized LDL-induced macrophage pyroptosis.
- To elucidate the underlying mechanism involving the Nrf2 pathway.
Main Methods:
- THP-1 macrophages were treated with high glucose/oxidized LDL, spermine, and an Nrf2 inhibitor (ML385).
- Assays included CCK-8 for viability, LDH and staining for membrane permeability, and PCR/Western blot for gene/protein expression.
- Reactive oxygen species (ROS) production was measured.
Main Results:
- Spermine significantly reduced pyroptosis and oxidative stress markers (LDH, ROS, cell swelling) induced by high glucose/oxidized LDL.
- Spermine decreased expression of pyroptosis-related proteins (NLRP3, cleaved caspase-1, N-GSDMD, IL-1β).
- Spermine activated the Nrf2 pathway, increasing nuclear translocation and downstream antioxidant enzymes (HO-1, NQO1), effects reversed by ML385.
Conclusions:
- Spermine protects against macrophage pyroptosis and oxidative stress by activating the Nrf2 pathway.
- Spermine demonstrates potential as a novel therapeutic agent for diabetic atherosclerosis by targeting macrophage pyroptosis.
