Qian Wang

Notopterol is a naturally occurring furanocoumarin compound found in the root of Notopterygium incisum. Hyperuricemia involves the activation of chronic inflammation and leads to cardiac damage. Whether notopterol has cardioprotective potential in hyperuricemia mice remains elusive. The hyperuricemic mouse model was constructed by administration of potassium oxonate and adenine every other day for six weeks. Notopterol (20 mg/kg) and allopurinol (10 mg/kg) were given daily as treatment, respectively. The results showed that hyperuricemia dampened heart function and reduced exercise capacity. Notopterol treatment improved exercise capacity and alleviated cardiac dysfunction in hyperuricemic mice. P2X7R and pyroptosis signals were activated both in hyperuricemic mice and in uric acid-stimulated H9c2 cells. Additionally, it was verified that inhibition of P2X7R alleviated pyroptosis and inflammatory signals in uric acid-treated H9c2 cells. Notopterol administration significantly suppressed expression levels of pyroptosis associated proteins and P2X7R in vivo and in vitro. P2X7R overexpression abolished the inhibition effect of notopterol on pyroptosis. Collectively, our findings suggested that P2X7R played a critical role in uric acid-induced NLRP3 inflammatory signals. Notopterol inhibited pyroptosis via inhibiting the P2X7R/NLRP3 signaling pathway under uric acid stimulation. Notopterol might represent a potential therapeutic strategy against pyroptosis and improve cardiac function in hyperuricemic mice.

Cuproptosis resulting from copper (Cu) overload has not yet been investigated in diabetic cardiomyopathy (DCM). Advanced glycosylation end products (AGEs) induced by persistent hyperglycemia play an essential role in cardiotoxicity. To clarify whether cuproptosis was involved in AGEs-induced cardiotoxicity, we analyzed the toxicity of AGEs and copper in AC16 cardiomyocytes and in STZ-induced or db/db-diabetic mouse models. The results showed that copper ionophore elesclomol induced cuproptosis in cardiomyocytes. It was only rescued by copper chelator tetrathiomolybdate rather than by other cell death inhibitors. Intriguingly, AGEs triggered cardiomyocyte death and aggravated it when incubated with CuCl₂ or elesclomol–CuCl2. Moreover, AGEs increased intracellular copper accumulation and exhibited features of cuproptosis, including loss of Fe–S cluster proteins (FDX1, LIAS, NDUFS8 and ACO2) and decreased lipoylation of DLAT and DLST. These effects were accompanied by decreased mitochondrial oxidative respiration, including downregulated mitochondrial respiratory chain complex, decreased ATP production and suppressed mitochondrial complex I and III activity. Additionally, AGEs promoted the upregulation of copper importer SLC31A1. We predicted that ATF3 and/or SPI1 might be transcriptional factors of SLC31A1 by online databases and validated that by ATF3/SPI1 overexpression. In diabetic mice, copper and AGEs increases in the blood and heart were observed and accompanied by cardiac dysfunction. The protein and mRNA profile changes in diabetic hearts were consistent with cuproptosis. Our findings showed, for the first time, that excessive AGEs and copper in diabetes upregulated ATF3/SPI1/SLC31A1 signaling, thereby disturbing copper homeostasis and promoting cuproptosis. Collectively, the novel mechanism might be an alternative potential therapeutic target for DCM.