Overexpression of LonP1 attenuated doxorubicin-mediated apoptotic signaling and mtDNA release in human cardiomyocytes, whereas decreasing LonP1 levels exacerbated these effects.
Does LonP1 overexpression attenuate doxorubicin-induced cardiomyocyte death and mtDNA release in human cardiac cells?
LonP1 overexpression attenuates doxorubicin-induced cardiomyocyte apoptosis and mtDNA release, highlighting its potential as a therapeutic target for preventing DOX cardiotoxicity.
Background Doxorubicin (DOX), a first-line chemotherapeutic agent, has been linked to severe off-target cardiotoxicity in the clinic. Previous works suggest that mitochondria are key mediators of this cardiotoxicity. Leakage of mitochondrial contents after DOX treatment, including mitochondrial DNA (mtDNA), is thought to activate apoptotic and inflammatory signaling pathways implicated in cardiomyocyte cell death. Whether the master mitochondrial protease, LonP1, can dampen these pathways and improve cardiomyocyte viability following DOX treatment remains unknown. Methods Human cardiac cells (AC-16) and primary (1°) human cardiomyocytes were subjected to DOX treatment, followed by bulk RNA-Seq, RT-qPCR, qPCR, and immunoblotting to assess apoptotic signaling, inflammatory signaling, mtDNA release, and LonP1 expression, respectively. Lentivirus transduction of AC-16 cells was used to generate both knockdown (KD) and overexpression (OE) LonP1 cell lines to determine the effects of altered LonP1 levels on DOX-induced apoptosis and mtDNA release. Further, levels of mitochondrial DNA (mtDNA) were measured using qPCR from serum samples obtained from patients undergoing DOX treatment to assess the clinical relevance of released mtDNA as a potential biomarker for the development of DOX cardiotoxicity. Results DOX treatment of AC-16 cells, as well as 1° human cardiomyocytes, upregulated both apoptotic and inflammatory signaling in both cell models. Increased LonP1 levels were also observed under DOX treatment in AC-16 cells and 1° human cardiomyocytes. Likewise, DOX increased mtDNA release from both cell lines, both prior to, and as a sequel to cell death. Decreasing LonP1 levels exacerbated DOX-mediated apoptotic signaling and mtDNA release, whereas overexpression of LonP1 attenuated these effects. Furthermore, DOX treatment in cancer patients increases plasma mtDNA levels. Conclusions These findings suggest LonP1 plays a protective role in the heart following DOX treatment, supporting LonP1 as a potential novel therapeutic target for prevention of DOX cardiotoxicity. Patterns of mtDNA release within patients undergoing DOX treatment also highlight the potential of mtDNA as a potential biomarker and target for prevention of DOX cardiotoxicity, justifying the need for more extensive, prospectively monitored cohort studies to expand upon these findings and statistically model mtDNA release patterns. Graphical Abstract
O’Dwyer et al. (Thu,) conducted a other in Doxorubicin-induced cardiotoxicity. LonP1 modulation (knockdown or overexpression) vs. Control cells was evaluated on Apoptotic signaling, inflammatory signaling, and mtDNA release. Overexpression of LonP1 attenuated doxorubicin-mediated apoptotic signaling and mtDNA release in human cardiomyocytes, whereas decreasing LonP1 levels exacerbated these effects.