HMOX1 silencing prevents doxorubicin-induced cardiomyocyte injury, mitochondrial dysfunction, and ferroptosis by downregulating CTGF

Doxorubicin is a type of effective antitumor drug but can contribute to cardiomyocyte injuries. We aimed to dissect the mechanism of the HMOX1/CTGF axis in DOX-induced cardiomyocyte injury, mitochondrial dysfunction, and ferroptosis.

Bioinformatics analysis was conducted to retrieve differentially expressed genes in a DOX-induced mouse model. Mouse cardiomyocytes, HL-1 cells, were induced with l µM DOX, after which gain- or loss-of-function assays were applied. CCK-8, fluorescent probe assay, flow cytometry, and corresponding kits were employed to detect cell viability, ROS levels, mitochondrial membrane potential and cell apoptosis, and GSH and Fe²⁺ contents, respectively. qRT-PCR or Western blot assay was adopted to test HMOX1, CTGF, BCL-2, Caspase3, Cleaved-Caspase3, and GPX4 expression.

Bioinformatics analysis showed that HMOX1 and CTGF were highly expressed in DOX-induced mice and correlated with each other. Also, HMOX1 and CTGF expression was high in HL-1 cells after DOX treatment, along with an obvious decrease in cell viability and GSH and GPX4 expression, an increase in ROS levels, apoptosis, and Fe²⁺ contents, and mitochondrial membrane potential dysfunction or loss. HMOX1 or CTGF silencing diminished cell apoptosis, Cleaved-Caspase3 expression, Fe²⁺ contents, and ROS levels, enhanced cell viability and the expression of GSH, GPX4, and BCL-2, and recovered mitochondrial membrane potential in DOX-induced HL-1 cells. Nevertheless, the effects of HMOX1 silencing on the viability, apoptosis, ferroptosis, and mitochondrial dysfunction of DOX-induced HL-1 cells were counteracted by CTGF overexpression.

In conclusion, HMOX1 silencing decreased CTGF expression to alleviate DOX-induced injury, mitochondrial dysfunction, and ferroptosis of mouse cardiomyocytes.