Overexpressed SIRT6 ameliorates doxorubicin-induced cardiotoxicity and potentiates the therapeutic efficacy through metabolic remodeling

Research progress on the role and mechanism of Sirtuin family in doxorubicin cardiotoxicity

BACKGROUND

Doxorubicin (DOX) is a widely utilized anthracycline chemotherapy drug in cancer treatment, yet its efficacy is hindered by both short-term and long-term cardiotoxicity. Although oxidative stress, inflammation and mitochondrial dysfunction are established factors in DOX-induced cardiotoxicity, the precise molecular pathways remain elusive. Further exploration of the pathogenesis and identification of novel molecular targets are imperative. Recent studies have implicated the Sirtuins family in various physiological and pathological processes, suggesting their potential in ameliorating DOX-induced cardiotoxicity. Moreover, research on Sirtuins has discovered small-molecule compounds or medicinal plants with regulatory effects, representing a notable advancement in preventing and treating DOX-induced cardiac injury.

PURPOSE

In this review, we delve into the pathogenesis of DOX-induced cardiotoxicity and explore the therapeutic effects of Sirtuins in mitigating this condition, along with the associated molecular mechanisms. Furthermore, we delineate the roles and mechanisms of small-molecule regulators of Sirtuins in the prevention and treatment of DOX-induced cardiotoxicity.

STUDY-DESIGN/METHODS

Data for this review were sourced from various scientific databases (such as Web of Science, PubMed and Science Direct) up to March 2024. Search terms included "Sirtuins," "DOX-induced cardiotoxicity," "DOX," "Sirtuins regulators," "histone deacetylation," among others, as well as several combinations thereof.

RESULTS

Members of the Sirtuins family regulate both the onset and progression of DOX-induced cardiotoxicity through anti-inflammatory, antioxidative stress and anti-apoptotic mechanisms, as well as by maintaining mitochondrial stability. Moreover, natural plant-derived active compounds such as Resveratrol (RES), curcumin, berberine, along with synthetic small-molecule compounds like EX527, modulate the expression and activity of Sirtuins.

CONCLUSION

The therapeutic role of the Sirtuins family in mitigating DOX-induced cardiotoxicity represents a potential molecular target. However, further research is urgently needed to elucidate the relevant molecular mechanisms and to assess the safety and biological activity of Sirtuins regulators. This review offers an in-depth understanding of the therapeutic role of the Sirtuins family in mitigating DOX-induced cardiotoxicity, providing a preliminary basis for the clinical application of Sirtuins regulators in this condition.

USP18 Stabilized FTO Protein to Activate Mitophagy in Ischemic Stroke Through Repressing m6A Modification of SIRT6

Ischemic stroke (IS) is a dangerous cerebrovascular disorder with a significant incidence and death rate. Ubiquitin-specific peptidase 18 (USP18) has been proven to mitigate ischemic brain damage; however, its potential regulatory mechanisms remain unclear. In vivo and in vitro models of IS were established by middle cerebral artery occlusion (MCAO) and oxygen-glucose deprivation/reoxygenation (OGD/R). Neurocyte injury was detected by MTT, LDH, ROS level, mitochondrial membrane potential (Δψm), and flow cytometry. Molecular expression was evaluated by qPCR, Western blotting, and immunofluorescence staining. Molecular mechanisms were determined by Co-IP, RIP, and MeRIP. IS injury was determined by neurological behavior score and TTC staining. Mitophagy was observed by TEM. USP18 and fat mass and obesity-associated protein (FTO) expression declined after OGD/R. Dysfunctional mitochondrial and apoptosis in OGD/R-stimulated neurocytes were eliminated by USP18/FTO overexpression via mitophagy activation. USP18-mediated de-ubiquitination was responsible for increasing FTO protein stability. Up-regulation of FTO protein restrained m6A modification of sirtuin6 (SIRT6) in a YTHDF2-dependent manner to enhance SIRT6 expression and subsequent activation of AMPK/PGC-1α/AKT signaling. FTO induced mitophagy to ameliorate nerve cell damage through SIRT6/AMPK/PGC-1α/AKT pathway. Finally, USP18/FTO overexpression relieved IS in rats via triggering SIRT6/AMPK/PGC-1α/AKT axis-mediated mitophagy. USP18 increased FTO protein stability to trigger SIRT6-induced mitophagy, thus mitigating IS. Our data unravel the novel neuroprotective mechanism of USP18 and suggest its potential as a promising treatment target for IS.

SIRT3/6: an amazing challenge and opportunity in the fight against fibrosis and aging

Fibrosis is a typical aging-related pathological process involving almost all organs, including the heart, kidney, liver, lung, and skin. Fibrogenesis is a highly orchestrated process defined by sequences of cellular response and molecular signals mechanisms underlying the disease. In pathophysiologic conditions associated with organ fibrosis, a variety of injurious stimuli such as metabolic disorders, epigenetic changes, and aging may induce the progression of fibrosis. Sirtuins protein is a kind of deacetylase which can regulate cell metabolism and participate in a variety of cell physiological functions. In this review, we outline our current understanding of common principles of fibrogenic mechanisms and the functional role of SIRT3/6 in aging-related fibrosis. In addition, sequences of novel protective strategies have been identified directly or indirectly according to these mechanisms. Here, we highlight the role and biological function of SIRT3/6 focus on aging fibrosis, as well as their inhibitors and activators as novel preventative or therapeutic interventions for aging-related tissue fibrosis.

Exploring the therapeutic potential of Sirt6-enriched adipose stem cell-derived exosomes in myocardial ischemia-reperfusion injury: unfolding new epigenetic frontiers

BACKGROUND

The management of myocardial ischemia-reperfusion injury (MIRI) presents continuous therapeutic challenges. NAD-dependent deacetylase Sirtuin 6 (Sirt6) plays distinct roles in various disease contexts and is hence investigated for potential therapeutic applications for MIRI. This study aimed to examine the impact of Sirt6-overexpressing exosomes derived from adipose stem cells (S-ASC-Exo) on MIRI, focusing on their influence on AIM2-pyroptosis and mitophagy processes. The sirtuin family of proteins, particularly Sirtuin 6 (Sirt6), play a pivotal role in these processes. This study aimed to explore the potential therapeutic effects of Sirt6-enriched exosomes derived from adipose stem cells (S-ASC-Exo) on regulating MIRI.

RESULTS

Bioinformatic analysis revealed a significant downregulation of Sirt6 in MIRI subjected to control group, causing a consequential increase in mitophagy and pyroptosis regulator expressions. Therefore, our study revealed that Sirt6-enriched exosomes influenced the progression of MIRI through the regulation of target proteins AIM2 and GSDMD, associated with pyroptosis, and p62 and Beclin-1, related to mitophagy. The introduction of S-ASC-Exo inhibited AIM2-pyroptosis while enhancing mitophagy. Consequently, this led to a significant reduction of GSDMD cleavage and pyroptosis in endothelial cells, catalyzing a deceleration in the progression of atherosclerosis. Extensive in vivo and in vitro assays were performed to validate the expressions of these specific genes and proteins, which affirmed the dynamic modulation by Sirt6-enriched exosomes. Furthermore, treatment with S-ASC-Exo drastically ameliorated cardiac functions and limited infarct size, underlining their cardioprotective attributes.

CONCLUSIONS

Our study underscores the potential therapeutic role of Sirt6-enriched exosomes in managing MIRI. We demonstrated their profound cardioprotective effect, evident in the enhanced cardiac function and attenuated tissue damage, through the strategic modulation of AIM2-pyroptosis and mitophagy. Given the intricate interplay between Sirt6 and the aforementioned processes, a comprehensive understanding of these pathways is essential to fully exploit the therapeutic potential of Sirt6. Altogether, our findings indicate the promise of Sirt6-enriched exosomes as a novel therapeutic strategy in treating ischemia-reperfusion injuries and cardiovascular diseases at large. Future research needs to underscore optimizing the balance of mitophagy during myocardial ischemia to avoid potential loss of normal myocytes.

SGK1 is involved in doxorubicin-induced chronic cardiotoxicity and dysfunction through activation of the NFκB pathway

Breast cancer is the predominant cancer among women worldwide, and chemotherapeutic agents, such as doxorubicin (DOX), have the potential to significantly prolong survival, albeit at the cost of inducing severe cardiovascular toxicity. Inflammation has emerged as a crucial biological process contributing to the remodeling of cardiovascular toxicity. The role of serum glucocorticoid kinase 1 (SGK1) in various inflammatory diseases has been extensively investigated. Here, we studied the molecular mechanisms underlying the function of SGK1 in DOX-induced cardiotoxicity in HL-1 cardiomyocyte cell lines and in a tumor-bearing mouse model. SGK1 was upregulated in the DOX-induced cardiotoxicity model, accompanied by increased levels of inflammatory factors. Furthermore, inhibition of SGK1 suppresses the phosphorylation of nuclear factor-kappa B (NFκB) in cardiomyocytes, which inhibits the production of inflammatory factors and apoptosis of cardiomyocytes, and has cardioprotective effects. Simultaneously, small interfering RNA targeting SGK1 inhibited the proliferation of breast cancer cells. Conversely, overexpression of SGK1 increases the phosphorylation of NFκB and aggravates myocardial injury. In conclusion, our study demonstrates that SGK1 promotes DOX-induced cardiac inflammation and apoptosis by promoting NFκB activity. Our results indicate that inhibiting SGK1 might be an effective treatment strategy that can provide both tumor-killing and cardioprotective functions. Further in vivo research is needed to fully elucidate the effects and mechanisms of combination therapy with SGK1 inhibitors and DOX in breast cancer treatment.