The regulatory roles of p53 in cardiovascular health and disease

Abstract

Cardiovascular disease (CVD) remains the leading cause of mortality globally, so further investigation is required to identify its underlying mechanisms and potential targets for its prevention. The transcription factor p53 functions as a gatekeeper, regulating a myriad of genes to maintain normal cell functions. It has received a great deal of research attention as a tumor suppressor. In the past three decades, evidence has also shown a regulatory role for p53 in the heart. Basal p53 is essential for embryonic cardiac development; it is also necessary to maintain normal heart architecture and physiological function. In pathological cardiovascular circumstances, p53 expression is elevated in both patient samples and animal models. Elevated p53 plays a regulatory role via anti-angiogenesis, pro-programmed cell death, metabolism regulation, and cell cycle arrest regulation. This largely promotes the development of CVDs, particularly cardiac remodeling in the infarcted heart, hypertrophic cardiomyopathy, dilated cardiomyopathy, and diabetic cardiomyopathy. Roles for p53 have also been found in atherosclerosis and chemotherapy-induced cardiotoxicity. However, it has different roles in cardiomyocytes and non-myocytes, even in the same model. In this review, we describe the different effects of p53 in cardiovascular physiological and pathological conditions, in addition to potential CVD therapies targeting p53.

Introduction

The heart is one of the most important organs of the body that works as a blood pump to provide the body with oxygen and nutrients. Heart health is, therefore, a vital factor contributing to the quality of life and longevity. Cardiovascular disease (CVD) is currently the leading cause of death worldwide. According to the 2020 update of American Heart Association Heart Disease and Stroke Statistics, CVD accounted for approximately 18 million deaths in 2017, and the expenditures for CVD surpassed the medical cost of any other chronic disease [1]. It is, therefore, urgent to determine the mechanisms underlying heart diseases. In the past three decades, p53 has received increased attention from researchers. A massive amount of evidence has shown that p53 is a transcription factor involved in regulating a myriad of genes by both transactivation and transrepression. These functions occur in response to stress stimuli, primarily, DNA damage, oncogene expression, ribosomal dysfunction, hypoxia, and oxidative stress. The elevation of p53 expression promotes apoptosis, cell cycle arrest, metabolism alteration, and autophagy [2, 3]. Because of these novel activities, p53 is mainly regarded as a crucial tumor suppressor. However, it also plays roles in other pathological processes [4–10], with its roles in various CVDs gaining attention. Annarosa et al. determined that p53 expression and activity increased in a dog model of pacing-induced cardiac dysfunction, accompanied by increased programmed cell death [11]. Increased p53 expression was detected in late-stage heart failure patients [12]. A growing body of research has demonstrated that p53 is necessary for embryonic heart development and adult heart homeostasis [13, 14]. Additionally, p53 exerts critical regulatory effects during CVDs including myocardial ischemia/reperfusion injury, pressure-overload or diabetic-induced maladaptive remodeling, heart failure, chemotherapy-induced cardiotoxicity, and atherosclerosis [15–18]. In this review, we, therefore, elaborate on the regulatory role of p53 in cardiovascular health and disease, in addition to evaluating potential preclinical treatments targeting p53.

Evidence for p53 activation in multiple CVDs

Congenital heart defects are the primary cause of infant and child mortality and a rapidly emerging global pediatric health issue [19]. Most of these defects are attributed to the complex interplay between maternal exposures and genetic susceptibilities of the fetus [20]. Many maternal exposures constitute risk factors, including certain drugs, irradiation, smoking, and hyperglycemia. These risk factors are associated with stress signals that can lead to p53 pathway activation. During embryonic and post-natal development, deregulated p53 activity can perturb the development of the heart by inducing apoptosis, limiting proliferation, or regulating other developmental programs in a cell type-dependent manner [21].

Regulation by p53 is also pivotal in the homeostasis of adult cardiomyocytes under physiological conditions. A recent study demonstrated that the deletion of p53 triggered murine heart hypertrophy and decreased heart function [14]. Under physiological conditions, p53 is functionally active to maintain the cardiac architecture and regulates the expression of transcriptomes related to metabolism, mitochondrial biogenesis, cardiac architecture, and excitation-contraction coupling.

Myocardial hypertrophy can occur as an adaptive response to chronically increased afterload to maintain heart pump function. However, permanently, pathological overload induces maladaptive hypertrophy and cardiac remodeling, resulting in heart failure [22–24]. Accumulated p53 in the hypertrophic heart mediates the transition from compensated hypertrophy to decompensated heart dysfunction through p53-dependent apoptosis and anti-angiogenesis [15, 25].

Myocardial infarction (MI) is the leading cause of cardiovascular death. Ischemia induces profound metabolic and ionic perturbations, causing loss of cardiac myocytes followed by post-infarction cardiac remodeling and dysfunction [26]. In these phenomena, p53 has been reported to regulate cardiac myocyte apoptosis, autophagy, and necrosis during ischemia and reperfusion injury and post-infarction cardiac remodeling [18, 27, 28].

Under diabetic conditions, the heart is exposed to hyperglycemia and increased fatty acids and cytokines. This results in maladaptive consequences, including cardiomyocyte remodeling and impaired cardiac function [29, 30]. Alterations to p53-mediated mitochondrial respiration, apoptosis, and senescence are also involved in the development of diabetic cardiomyopathy [16, 31].

Doxorubicin is a member of the anthracycline family that is extensively used for anticancer chemotherapy. Although highly effective, doxorubicin causes p53-related cardiotoxicity [32–34]. However, the function of p53 is paradoxical among models involving different doxorubicin dosage and treatment duration. p53 promotes cardiotoxicity by mediating cell death in the acute stage of doxorubicin treatment [32, 33]. In late-onset cardiotoxicity in mice induced by low-dose doxorubicin treatment, p53 exerts cardiac protection via maintaining mitochondrial function [35]. A study targeting different properties of p53 in heart and tumor tissues from the doxorubicin-treated mice provided a possible viable option for p53-mediated cardioprotection [36], and the details are outlined below.

Atherosclerosis is a multifactorial arterial disease. The pathological plaque formation involves macrophages, vascular smooth muscle cells (VSMCs), and endothelial cells (ECs). The expression of p53 is increased in atherosclerotic plaques of patient samples [37]. Dysregulated p53 plays an atheroprotective or opposite role in different cell types, which occurs via p53-dependent growth arrest and an apoptotic response to multiple stresses.

Below, we mainly highlight the key features of p53 under different cardiac pathological conditions, illustrated in Fig. 1.

Fig. 1.

p53 effects in multiple CVDs

p53 modification in multiple CVDs

Under physiological circumstances, p53 is maintained at a very low level via the ubiquitin-proteasome system (UPS) [38]. Once stimulated by stress, p53 undergoes translational or post-translational modification and is stabilized. Activated p53 binds target genes or translocates to the cytoplasm to carry out its regulatory roles [39]. In multiple cardiac pathologies, p53 is stabilized by the modification of ubiquitination, phosphorylation, acetylation, SUMO(small ubiquitin-like modifier)ylation, and glycosylation.

Ubiquitination plays a pivotal role under both physiological and pathological cardiac conditions, acting as a post-translational modification of p53 via the UPS. Among the ubiquitin enzymes, the E3 ubiquitin ligase murine double minute 2 (MDM2) plays a necessary role in regulating p53 protein expression [40]. Under physiological conditions, p53 drives MDM2 expression, which in turn triggers the ubiquitination of p53. Proteasomes mediate the degradation of ubiquitinated p53, which leads to an overall reduction in p53 protein levels [38]. The negative feedback loop between p53 and MDM2 plays a critical role in p53 homeostasis. In hypertrophic and dilated cardiomyopathy, the UPS participates in regulating elevated p53 expression [41, 42]. Expression of p53 is elevated in heart samples of patients with dilated cardiomyopathy. However, the expression of MDM2 and HAUSP, an enzyme targeting p53 for deubiquitination, are both significantly elevated compared to that in healthy tissues. Although the deubiquitinating enzyme HAUSP is significantly elevated, this cannot be the primary reason for the concurrent increase in p53 and MDM2 expression, as similar expression levels of other deubiquitinating enzymes are detected in tissues from hearts with dilated cardiomyopathy and healthy hearts. Furthermore, the generally increased ubiquitination and elevated proteasomal activity levels are detected in dilated cardiomyopathy tissues [41]. The UPS regulates numerous fundamental physiological activities in cardiomyocytes [43–45]; in addition, ubiquitinated proteins accumulate before the onset of cardiac dysfunction in animal pressure-overload models [46]. Therefore, the elevation of p53, MDM2, and HAUSP expression suggests that the cardiac UPS is overwhelmed in end-stage dilated cardiomyopathy, making it unable to degrade the increased amount of ubiquitinated proteins, including p53 [41]. As a homolog of MDM2, MDM4 is also a p53-negative regulator in some cancers [47]. MDM4 deletion in the heart causes dilated cardiomyopathy via apoptosis-mediated cardiomyocyte loss; this effect can be restored by p53 deletion [48].

Atsuhiko et al. reported that the C-terminus of heat shock cognate protein 70-interacting protein (CHIP), an endogenous p53 antagonist in the heart, was required for p53 degradation to keep it at a low level. CHIP was initially identified as a cochaperone of heat shock cognate protein (HSP) 70. Given its U-box domain, CHIP has ubiquitin ligase activity and acts as an E3 ubiquitin ligase [49]. However, unlike MDM2, there is no negative feedback loop between p53 and CHIP. Under acute hypoxic conditions, CHIP expression was downregulated by hypoxia-inducible factor-1 (Hif-1)-mediated suppression at the transcriptional level, which contributed to p53 accumulation in cardiomyocytes by reducing its degradation. Accumulated p53 triggers remodeling and apoptotic cell death in post-infarcted cardiomyocytes; this pro-apoptotic effect can be attenuated by CHIP overexpression [50].

In human umbilical vein ECs, phosphorylated PKCζ, a member of the protein kinase C (PKC) family, initiates p53 SUMOylation in response to disturbed flow-mediated reactive nitrogen species. The C-terminal segment of the PKCζ, kinase domain associates with the RING domain of PIASy E3 SUMO ligase PIASy, resulting in increased PIASy enzymatic activity. This association mediates p53 SUMOylation, leading to the nuclear export of p53 [51].

Phosphorylation is a classical post-translational modification of p53 that affects p53-MDM2 interaction [39]. The phosphorylation of p53 at Ser15 mediates cardiomyocyte apoptosis in both in vivo and cultured models of doxorubicin-induced cardiotoxicity [33, 52]. In response to DNA damage, Rho-associated coiled-coil-containing protein kinase 1 (ROCK-1) and activated mitogen-activated protein kinase (MAPK) mediate p53 phosphorylation at Ser15 in diabetic and MI models [53, 54]. Activated MAPK also induces p53 phosphorylation at Ser390 in cultured myocytes exposed to hyperglycemia [55].

Acetylation is another p53 post-translational modification. Increased p53 acetylation has been detected in models of diabetic cardiomyopathy and heart failure, which induced cardiac myocyte apoptosis. Furthermore, p53-mediated apoptosis has been restored by sirtuin-1 via deacetylation [56, 57].

It has recently been verified that non-coding RNAs regulate p53 expression at the translational level and its activity as a transcription factor in CVDs. In a cardiac hypertrophy mouse model, elevated microRNA (miR)-125b repressed p53 expression by targeting the 3' UTR of p53 mRNA, which then mediated fibroblast proliferation [58]. Similarly, miR-221 downregulated cardiomyocyte p53 protein expression by the same mechanism in an ischemic model [59]. Long non-coding RNA (lncRNA) cardiac autophagy inhibitory factor (CAIF) decreased p53 transcriptional activity by directly interacting with the p53 protein. This blocked p53-mediated myocardin transcription, resulting in the inhibition of autophagy in an ischemic model [27]. Besides direct control, non-coding RNAs also regulate p53 by targeting its regulators, such as sirtuin-1 and MDM2 [60, 61].

Primary mechanisms by which p53 is involved in the pathogenesis of CVDs

p53-dependent anti-angiogenesis

Myocardial angiogenesis is necessary to meet the increased demand for blood supply by the heart. In CVDs, p53-mediated anti-angiogenesis has primarily been demonstrated in pressure-overload hypertrophy model, and diabetic cardiomyopathy models [31, 62].

Cardiac hypertrophy and dysfunction gene program network analysis showed that the accumulation of DNA damage, induced by oxidative stress, triggered p53 activation in hypertrophic cardiomyocytes [24, 63]. The DNA damage response signaling pathway is activated after DNA damage, at which point the p53 N-terminus is phosphorylated by phosphorylated ataxia telangiectasia mutated kinase. This kinase stabilizes p53 by inhibiting MDM2 binding [64]. In CVDs, p53 has an anti-angiogenetic effect by regulating the expression of Hif-1α.

Under normoxic conditions, Hif-1α is unstable due to the oxygen-dependent regulation by prolyl hydroxylases domain enzymes (PHDs) and von Hippel-Lindau protein (pVHL). Hif-1α is hydroxylated by PHDs, which require 2-oxoglutarate and ascorbate [65]. The hydroxylation of Hif-1α triggers the binding of pVHL to HIF-1α [66], which is followed by HIF-1α poly-ubiquitination and proteasomal degradation [67]. In the early hypertrophy stage, PHD activity is inhibited due to hypoxia, resulting in Hif-1α stabilization. Stabilized Hif-1α functions as a transcription factor to regulate multiple genes encoding hypoxia-associated proteins and angiogenic growth factors. This plays an essential protective role in the pathophysiology of pressure-overload hypertrophy, promoting coordinated vascular growth in the heart to meet the increased demand for blood supply [62, 68, 69]. Sustained pressure-overload induces p53 accumulation in the late stage of hypertrophy. Stabilized p53 acts as a molecular chaperone and recruits Hif-1α for MDM2 ubiquitination-mediated proteasomal degradation in an oxygen-independent manner (Fig. 2) [70, 71].

Fig. 2.

p53-dependent anti-angiogenesis in pressure-overload-induced cardiac hypertrophy. (Left) Under normoxic conditions, Hif-1α is hydroxylated by PHDs, which require oxygen. pVHL binds to the hydroxylated Hif-1α, followed by HIF-1α poly-ubiquitination and proteasomal degradation. (Middle) In the early stage of pressure-overload-induced cardiac hypertrophy, the activity of PHDs is inhibited, leading to the accumulation of Hif-1α. Stabilized Hif-1α acts as a transcriptional factor to regulate angiogenic growth factors, stimulating vascular growth in the heart to meet the increased demands for blood supply. (Right) Sustained pressure-overload-induced p53 accumulation in late stage of hypertrophy. Stabilized p53 facilitates the recruitment of Hif-1α for MDM2 ubiquitination-mediated degradation. The suppression of Hif-1α inhibits angiogenic growth factors, and the resulting mismatch between cardiac angiogenesis and hypertrophy thereby causes maladaptive hypertrophy, which progresses to heart dysfunction. Hif-1α hypoxia-inducible factor-1, PHD prolyl hydroxylase domain enzyme, pVHL von Hippel-Lindau protein, VEGF vascular endothelial growth factor, Ang-1 angiopoietin-1, MDM2 murine double minute 2, Ub ubiquitin

In the type I diabetic heart, increased p53 reduces the mRNA expression of Hif-1α. However, Hif-1α protein expression can be restored by p53 inhibition, which can be explained by the decrease in p53-mediated Hif-1α-MDM2 interaction and consequent Hif-1α ubiquitination-induced degradation [31]. The repression of Hif-1α expression induced by p53 inhibits vascular endothelial growth factor (VEGF) and angiopoietin-1 activity (Fig. 2). Additionally, the imbalance between impaired cardiac angiogenesis and hypertrophy causes maladaptive hypertrophy, which progresses to heart dysfunction [62, 72]. In endothelial cell-specific p53 deletion mice with cardiac hypertrophy, reduced Hif-1α degradation, increased VEGF expression, and improved cardiac vascularization were observed [73]. As a part of the Hif-1α-targeted regulation of angiogenesis, impaired VEGF expression was associated with inadequate neovascularization in diabetic cardiomyopathy [74]. Overexpression of exogenous Canopy 2, another p53-Hif-1α-regulated angiogenic growth factor, also attenuates the transition from compensatory hypertrophy to dilated heart failure in a mouse model [75].

In CVDs, oxidative stress activates p53 directly or indirectly by inducing oxidative DNA damage [16, 76, 77]. Based on the intensity of oxidative stress, p53 exerts anti- or pro-oxidative effects [78]. In response to mild stress, p53 transactivates anti-oxidative target genes, and the corresponding protect cells from oxidative stress injuries. However, in response to excessive oxidative stress, like in cardiomyocytes under pressure-overload, p53 exerts pro-oxidative stress roles by inhibiting the expression of the anti-oxidative factors SOD2 and sirtuin-3 [14], or triggers cell death (apoptosis, autophagy, or necrosis) in an oxidative stress-dependent manner[18, 27, 79]. Antioxidants treatment inhibits p53 activation thereby impending apoptosis of cardiomyocytes in the remote non-infarcted area [79].

p53-dependent apoptosis

As a tumor suppressor, regulating apoptosis is a fundamental role of p53 [80]. It also exerts a pro-apoptotic effect in most pathological processes involved in CVDs. There are three classic signaling pathways inducing apoptosis: the extrinsic pathway, the intrinsic pathway, and the endoplasmic reticulum (ER) stress pathway. The function of p53 has mainly been described in intrinsic pathway-induced apoptosis, which is initiated by mitochondria [81]. Intrinsic apoptosis can be activated by DNA damage, which is common in CVDs and mediated by the B-cell lymphoma 2 (Bcl-2) family proteins, which are localized in the outer membrane of mitochondria [81]. Their corresponding gene promoters contain consensus p53-binding elements [82]. Bcl-2 family proteins can be categorized into three subsets: Bcl-2-like proteins, which function as anti-apoptotic proteins and include Bcl-2, Bcl-x, Bcl-XL, and BAG; BH3-only proteins, which include Bad, Bid, Bim, Puma, Bnip3, and Noxa; and the cell death effectors Bax and Bak. BH3-only proteins and Bax/Bak function as pro-apoptotic proteins [83, 84]. Initially, p53 triggers apoptosis by activating BH3-only proteins, which prevents anti-apoptotic Bcl-2 proteins from inhibiting Bax and Bak. Some BH3-only proteins can also bind and activate the two cell death effectors [84].

In an ischemia/reflow injury rat model, p53 was acetylated at the Lys118 residue, which mediated p53 accumulation and Bax promoter binding. This acetylation was regulated by TIP60 acetylase, which reversed p53 acetylation after oxygenation of the MI heart. Unlike acetylated p53 that promoted apoptosis via Bax, deacetylated p53 played a pro-survival role in oxygenated MI hearts by binding the corresponding endothelial nitric oxide synthase gene promoter [28]. In a mouse model of pressure-overload hypertrophy, p53 silencing failed to induce PUMA expression, and the deletion of the gene encoding PUMA delayed cardiac dysfunction by attenuating apoptosis [85]. Increased levels of p53 triggered apoptosis in doxorubicin-induced cardiotoxicity and heart failure models. PUMA and Bax were also simultaneously upregulated, with or without alteration of Bcl-2 and Bcl-xl expression [57, 86].

As a death effector of the intrinsic apoptosis pathway, Bax promotes the opening of the mitochondrial permeability transition pore, resulting in the alteration of the mitochondrial transmembrane potential. This alteration accelerates the release of pro-apoptotic proteins from the intermembrane space into the cytosol [87], promoting apoptosis in a caspase-dependent/independent manner [88–90]. The critical role of Bax in ischemia/reperfusion injury has been illustrated in hearts isolated from Bax knockout mice, which exhibited a 50% reduction in infarct size and superior cardiac function due to apoptosis reduction [91]. Among CVD models, p53-mediated apoptosis accompanied by the elevated expression of downstream targets of Bax, including cytochrome c, apoptosis-inducing factor (AIF), Apaf-1, activated caspase-3, and caspase9 (Fig. 3). This findings indicated the important role of the p53-mediated intrinsic apoptosis pathway in CVDs [31, 53, 57, 86, 92].

Fig. 3.

p53-dependent apoptosis pathway in CVDs. p53 exerts pro-apoptotic activity by regulating Bcl-2 family proteins in CVDs. p53 regulates IGF-1R expression epigenetically by associating with HDAC1, which attenuates the pro-survival effect of IGF-1R. Bcl-2 B-cell lymphoma 2 family protein, Cyt c cytochrome c, IGF-1R insulin-like growth factor-1 receptor, AIF apoptosis-inducing factor, Apaf-1 apoptotic protease activating factor-1, GRP78 78-kDa glucose-regulated protein, Meg3 long non-coding RNA Meg3, FUS fused in sarcoma, cl-caspase-3 cleaved caspase-3, cl-caspase9 cleaved caspase9

Besides participating in the intrinsic apoptosis pathway, p53 has been shown to promote apoptosis in response to ER stress in cardiomyocytes [93]. During ER stress, p53 is activated in some cell lines [94–96]. In response to ER stress, protein kinase RNA-like ER kinase (PERK), one of the main sensors localized at the ER membrane, mediates the interaction of MDM2 with ribosomal proteins (rpL5, rpL11, rpL23), thereby contributing to the decrease in MDM2-mediated p53 ubiquitination and degradation [97]. Giorgi et al. reported that p53 accumulated at the ER and bound to sarco/ER Ca2+-ATPase (SERCA), thereby changing the oxidative state of the calcium pump and increasing Ca2+ transfer to mitochondria. Ca²⁺ overload of mitochondria induced apoptosis and altered its morphology [98]. Deletion of p53 reduced mitochondria injury and the amount of apoptotic cardiomyocytes after thapsigargin-induced ER stress [93]. However, the role of p53 in ER stress remains an open question, as its expression was inhibited in some cells upon ER stress [99]. More importantly, even in models with activated p53, the deletion of p53 partially inhibited the ER stress-induced apoptosis [96], suggesting that other pathways could be involved.

p53 could also exert its pro-apoptotic function by regulating the expression of non-coding RNA. Expression of the lncRNA Meg3 was upregulated by p53 in both an MI mouse model and cultured hypoxic cardiomyocytes. Meg3 then directly bound the RNA binding protein FUS to form an RNA-protein complex. FUS has been identified as a tumor suppressor, partially because of its induction of apoptosis [100]. In a cardiac ischemic model, the Meg3-FUS complex promoted apoptosis by downregulating Bcl-2 and upregulating caspase-3 expression [101]. Under high-glucose conditions, p53 triggered apoptosis via epigenetic regulation of insulin-like growth factor-1 receptor (IGF-1R). High glucose upregulated the association of p53 with histone deacetylase 1 and consequently downregulated the association between acetylated histone-4 and the Igf1r promoter. Reduction of IGF-1R expression, which was reported to ameliorate apoptosis [102], exerted pro-apoptotic activity in cultured cardiomyocytes [103]. In a model of Van Nostrand’s CHARGE syndrome, a developmental syndrome including heart defects, p53^25,26,53,54, allelic series of p53 transactivation domain mutant knock-in embryos exhibited heart outflow tract and ventricular septation defects, accompanied by atrioventricular cushion defects [21]. The mutations of p53^25,26,53,54 disrupt the p53-Mdm2 interaction [104]. Stabilized p53 exerted a pro-apoptotic effect by targeting Noxa, a BH3-only protein [21]. This p53-Noxa-induced apoptosis has also been observed in diabetic cardiomyopathy [54]. However, the details of the p53-Noxa apoptosis pathway in CVDs, which may mediate the intrinsic apoptosis pathway, require further study.

Besides the direct induction of apoptosis, p53 can also indirectly regulate apoptosis. In diabetic cardiomyopathy, glycosylated p53 mediated the upregulation of angiotensin II synthesis and the consequent phosphorylation of p38 MAPK. The activated p38 MAPK mediated p53 phosphorylation at Ser390 and Ser18. Thereafter, stabilized p53 triggered mitochondria-mediated apoptosis [55]. As described above, p53-mediated apoptosis contributes to cardiac remodeling and dysfunction in ischemic/reperfusion injury, pressure-overload hypertrophy, diabetic cardiomyopathy, and doxorubicin-induced cardiotoxicity. However, its role in atherosclerosis is currently unclear.

In human umbilical vein ECs subjected to disturbed flow, p53 activation mediated its nuclear export via SUMOylation. Upon entering the cytoplasm, p53 interacted with Bax and Bcl-2, inducing EC apoptosis [51]. The effect of p53 on VSMC apoptosis is contradictory. Double-mutant Tp53^−/−/ApoE^−/− mice showed increased aortic plaque formation and reduced apoptosis, including of VSMCs, compared with those in ApoE^−/− mice expressing wild-type p53 [17]. In an artery injury mouse model, a smooth muscle-specific Tp53 knockout reduced VSMC apoptosis [105]. These two in vivo models revealed the pro-apoptotic effect of p53 in VSMCs. However, another Tp53^−/−/ApoE^−/− mouse model revealed that Tp53^+/+ bone marrow transplantation reduced aortic plaque formation and apoptosis, demonstrating the anti-apoptotic effect of p53 in VSMCs. Mercer et al. established a cell-culture VSMC model to mimic the in vivo model; the cell-cultured model showed similar potential anti-apoptotic effects of p53. The possible protective mechanism of p53 may be the p53-induced repair of DNA damage from oxidation, which is common in atherosclerosis [17]. The different effects of p53 in VSMCs during atherosclerosis may be attributed to different stages of plaque, p53 expression levels in VSMCs, and the origin of VSMCs [106].

p53-dependent autophagy

Autophagy is an evolutionarily conserved mechanism of cytoplasmic element degradation that plays a dual role in homeostasis and facilitating cell death [107, 108]. There are four main autophagy pathways mediated by AMP-activated protein kinase (AMPK), mammalian target of rapamycin complex 1 (mTORC1), ER stress, and p53, respectively [81]. The p53 protein plays a dual role in regulating autophagy according to its subcellular location. As a transcription factor, nuclear p53 activates autophagy, which then facilitates cell death [109]. However, in the cytoplasm, p53 inhibits autophagy via the inhibition of AMPK and the activation of mTOR [110].

In CVDs, p53-mediated autophagy (Fig. 4a) contributes to the death of ischemic cardiomyocytes [27, 111]. However, p53-related mitophagy is cardioprotective for MI and doxorubicin-induced cardiotoxicity [32, 112].

Fig. 4.

Roles of p53 in autophagy/mitophagy, necrosis, and senescence. a p53-mediated autophagy and mitophagy pathways. b p53-dependent necrosis pathway in CVDs. c p53-dependent cell cycle arrest during atherosclerosis. p53 regulates the atherosclerosis process by regulating the cell cycle arrest of atherosclerotic cells. p53 inhibits macrophages and ECs proliferation via the p53-p21/GADD45 pathway. p53 triggers the telomere dysfunction-mediated senescence of VSMCs via Siah-1-TRF2. p53 promoted ECs senescence through the p53/p21 pathway. Bnip3 BCL-2 and adenovirus E1B 19 kDa-interacting protein 3, TIGAR Tp53-induced glycolysis and apoptosis regulator, Mfn1 mitofusin 1, NRF long non-coding RNA necrosis-related factor, miR-873 micro-RNA-873, RIPK1 receptor-interacting serine/threonine-protein kinase 1, RIPK3 receptor-interacting serine/threonine-protein kinase 3, ARC apoptosis repressor with caspase recruitment domain, Cyp D cyclophilin D, GADD45 growth arrest and DNA damage-inducible protein 45, TRF2 telomeric repeat-binding factor-2

In a model of cardiac ischemic/reperfusion injury, increased p53 expression mediated the activation of autophagy both in the area at risk and in remote areas. This occurs via p53 binding to the promoter of the Myocd gene encoding myocardin, a transcriptional coactivator regulating apoptosis and autophagy that is specifically expressed in cardiac and smooth muscles [113]. The activated myocardin facilitates autophagy, as evidenced by the increased autophagy flux, via activation of Beclin 1, which initiates autophagy and thus induces programmed cell death in cardiomyocytes [114]. Under hypoxic conditions, this p53-mediated autophagy pathway can be regulated by the lncRNA CAIF, as mentioned above. Exogenous CAIF overexpression can inhibit p53-mediated autophagy, resulting in a reduction in infarct size and superior cardiac function [27]. BCL-2 and adenovirus E1B 19 kDa-interacting protein 3 (Bnip3), a member of the BH3-only protein family, also participate in p53-mediated autophagy and cell death in ischemic cardiomyocytes [115]. The overexpression of p53 in post-natal cardiomyocytes transcriptionally activated Bnip3, which triggered autophagic flux [111]. In cardiomyocytes and infarcted mouse hearts cultured under hypoxic conditions, miR-125b inhibited the p53-Bnip3 signal, autophagic flux, and cell death [116].

Another important p53 function is in mitophagy, a process by which damaged mitochondria are removed and digested through autophagy. Cardiomyocytes in Tp53 null mutant MI mice exhibited increased autophagosomes containing damaged mitochondria. However, after ischemia, the cardiomyocytes in control wild-type mice contained more damaged and total mitochondrial DNA and exhibited lower Bnip3 expression than mutant mice. This indicates that p53 inhibited mitophagy and induced the accumulation of damaged mitochondria, playing a crucial role in damaged mitochondria-mediated apoptotic cell death without disrupting energy homeostasis. Activated Bnip3 and increased mitophagy induced by p53 deletion was mediated by a decrease in TIGAR, which improved post-infarct remodeling and played an important role in cardioprotection [112]. Additionally, in a doxorubicin-induced cardiotoxicity model, cytosolic p53 exhibited an inhibitory effect on mitophagy by targeting Parkin, which contributed to impaired mitochondrial function and cardiac dysfunction [32]. In response to damaged mitochondria, Parkin, as an E3 ubiquitin ligase, triggers the ubiquitination and subsequent proteasomal degradation of outer mitochondrial membrane proteins such as Mfn1 and Mfn2. This Parkin-mediated degradation inhibits mitochondrial fusion and promotes mitophagy [117]. Cytosolic p53 bound to Parkin and inhibited its translocation to damaged mitochondria and the subsequent Mfn1 degradation, which facilitated a reduction in mitophagy [32].

The mechanism of the dual pro-autophagic and pro-mitophagic role of p53 in CVDs is unclear. The role of p53 may be attributed to its location [110, 118]; however, its detailed mechanism requires further study.

p53-dependent necrosis

In contrast to traditional opinion, a growing body of evidence suggests that necrosis is a regulated and programmed method of cell death, rather than being an unregulated, accidental, and irreversible process [119]. The forms of programmed necrosis are primarily necroptosis, mitochondrial permeability transition (MPT)-dependent necrosis, pyroptosis, and ferroptosis. Among them, necroptosis and MPT-dependent necrosis contribute to the pathogenesis of MI and heart failure [120]. It has been shown that p53 participates in MPT-dependent necrosis by triggering the opening of the mitochondrial permeability transition pore (mPTP), a non-specific channel of the inner mitochondrial membrane [121, 122]. The opening of the mPTP has an essential role in triggering MPT-dependent necrosis by disrupting mitochondrial respiration, inducing matrix swelling, and destroying the integrity of the mitochondrial membrane, ultimately resulting in necrotic cell death [123]. In mouse embryonic fibroblasts, oxidative stress-induced p53 accumulation could trigger mPTP opening and mediate MPT-dependent necrosis by directly interacting with CypD, a central regulator of mPTP [122, 124]. In an ischemic stroke mouse model, reducing p53 or blocking the formation of the p53/CypD complex inhibited necrosis [122].

Alternatively, in oxidative stress-induced cardiomyocyte necrosis, p53 triggered CypD-mediated MPT-dependent necrosis by targeting the apoptosis repressor with a reduction in caspase recruitment domain (ARC) at the transcriptional level (Fig. 4b). In an ischemia/reperfusion injury mouse model, reduction of ARC overexpression-induced necrosis resulted in decreased myocardial infarct size and improved cardiac function [18]. Moreover, p53 bound to the promoter of the lncRNA necrosis-related factor as a transcription factor. This triggered the activation of receptor-interacting serine/threonine-protein kinase 1 (RIPK1)/RIPK3 by reducing the suppressive effect of miR-873 on RIPK1 and RIPK3 translation (Fig. 4b) [125]. RIPK1 and RIPK3 form the necrosis-inducing complex, which is essential for programmed necrosis [126]. In response to oxidative stress, phosphorylated p53 repressed peroxisome proliferator-activated receptor-c coactivator-1α (PGC1α), a master regulator associated with mitochondrial function. The reduction in PGC1α induced by p53 contributed to cardiac bioenergetic and ultrastructural mitochondrial defects, which induced cardiomyocyte necrosis [127]. Necrosis mediated by p53 is crucial in ischemic cardiomyocytes, and its precise mechanism of action requires further study.

p53-dependent metabolic alterations

It has been demonstrated that p53 exerts a regulatory role in metabolism [128]. Metabolic remodeling, including the alteration of metabolism and mitochondrial function, is an early event preceding cardiac dysfunction [24, 129], with p53 playing an essential role in both metabolic fuel sensing in the heart and regulation under physiological conditions, thereby maintaining homeostasis in adult cardiomyocytes. The ablation of p53 induces a change in the mRNA levels of the metabolic sensors Lkb1/Ampk1, which can promote insulin sensitivity and fatty acid oxidation (FAO). In the absence of p53, there are changes in the expression of genes regulating glucose and fatty acid metabolism, including the glucose transporter GLUT4, 9 of the 11 steps of glycolysis, and genes essential for FAO, fatty acid transport (CD36/Lpl/Cpt1b), and fatty acid synthesis (ACC2) [130]. In the chronic stage of low-dose doxorubicin treatment mice model, p53 deletion mediated cardiotoxicity via a decrease in FAO and a compensatory increase in glycolysis [35]. A decrease in the mitochondrial mass and DNA content was the main reason for the observed doxorubicin-induced metabolic alteration. Mechanistically, Li et al. demonstrated that a reduced expression of mitochondrial transcription factor A and a lower level of the p53 target gene RRM2B, which is pivotal for mitochondrial DNA transcription, maintenance [131, 132], and repair [133], contributed to the cardiotoxicity [35]. A cardiomyocyte gene program showed that p53 is pivotal for molecular metabolic remodeling during the transition from hypertrophy to cardiac dysfunction. During pressure-overload-induced cardiac hypertrophy, the expression of genes related to mitochondrial ribosomes and oxidative phosphorylation were induced to meet the demand for increased energy. In late-stage hypertrophic cardiomyocytes, p53 mediated a decrease in mitochondrial ribosomes and oxidative phosphorylation, which disrupted the adaptive metabolism in hypertrophy [24]. Therefore, the change in both metabolic sensors and regulators caused by the p53 network explains the balance between energy demand, fuel uptake, and metabolism, which is essential for stable cardiac function in various hemodynamic settings.

The alteration of mitochondrial respiration contributes to a reduction in cardiac efficiency. Papadopoulou et al. demonstrated that p53 participates in the regulation of mitochondrial respiration by regulating of cytochrome c oxidase 2(SCO2)-mediated impaired mitochondrial respiration. SCO2 has an essential role in the assembly of the cytochrome c oxidase complex in the mitochondria. As the cytochrome c oxidase complex is the center for oxygen consumption, mutations inactivating this complex or targeting genes that are related to aerobic respiratory failure in humans are responsible for fatal cardioencephalomyopathy [134]. Matoba et al. verified that in colon cancer cells, p53 directly transactivates SCO2 transcription to regulate aerobic respiration in mitochondria [135]. In the diabetic heart, p53 expression was upregulated by diabetes-induced oxidative stress, which mediated SCO2 upregulation in both type I and type II diabetes mellitus. The upregulated p53/SCO2 system enhanced the activity of mitochondrial complex IV, which has the greatest oxygen consumption capacity among the mitochondrial complexes I–IV. The increased mitochondrial respiration promoted cardiac lipotoxicity via an increase in FAT/CD36 and the generation of mitochondrial reactive oxygen species, leading to diabetic cardiomyopathy progression [16]. Also, in the diabetic heart, p53 could regulate glucose metabolism by decreasing the expression of glucose transporters GLUT-1 and GLUT-4 and key glycolytic enzymes [31]. This resulted in the reduction of cardiac glucose uptake and usage [136]. In diabetic cardiomyopathy, p53 inhibition restored impaired glucose metabolism by restoring the expression of Hif-1-α and its downstream targets [31].

p53-dependent cell cycle arrest in CVDs

Critical roles of p53 have been demonstrated in several fundamental cellular signaling pathways. As a transcription factor, p53 downregulates genes that encode proteins associated with cell cycle checkpoints which are required for cell cycle progression. The classical p53/p21 pathway regulates cell cycle arrest [137–139]. p53 targets checkpoint regulators from the G1 phase to the end of mitosis to regulate proliferation and the progress of senescence [140].

The pathology of atherosclerosis involves p53-imediated regulation of the proliferation and senescence of atherosclerosis-related cells. As a major cellular component of plaques, macrophages perform critical functions in modulating atherosclerosis by taking up native and modified lipoproteins, and transforming them into foam cells [141]. In human atherosclerotic lesions, p53 colocalized with non-proliferating macrophages. Additionally, as a cyclin-dependent kinase (CDK) inhibitor, p21 colocalized with p53 in macrophages [142]. The inactivation of p53 increased macrophage proliferation, which resulted in an increase in atherosclerotic lesions (Fig. 4c) [143, 144].

EC dysfunction, including altered vasoregulation, activation of inflammation, and increased cell adhesion molecule expression is induced in atherogenic environments, promoting atherosclerosis [145, 146]. EC senescence has been identified in plaque lesions [147]. The immunoreactivity of PATZ1, a transcriptional repressor [148], is weak from ECs in elderly human arteries and mouse atherosclerotic plaques. PATZ1 silencing induced G0/G1 arrest in young human umbilical vascular ECs mediated by the p53/p21 pathway [149]. As reviewed, a disturbed blood flow promotes atherogenesis through regulating proliferation, differentiation, apoptosis, and inflammation of ECs by different signaling molecules and gene expression patterns [150]. Recently, studies have revealed that this disturbed flow promotes EC senescence by activating p53. In a disturbed flow-induced atherosclerosis model, senescent ECs accumulated at atheroprone sites and had higher p53 and p21 expression levels. Either p53 or p21 silencing reduced the rates of EC senescence. Furthermore, p53 silencing simultaneously reduced p21 expression and thus the shear stress caused by the disturbed flow-promoted EC senescence through the p53/p21 pathway (Fig. 4c). Moreover, sirtuin-1, which negatively regulates p53 by deacetylation, reduced the incidence of EC senescence [151, 152]. Conversely, undisturbed flow-induced growth arrest may protect ECs from apoptosis. Cultured ECs were exposed to an environment of laminar shear stress, which activated p53 in ECs via JNK-mediated phosphorylation and enhanced the promoter activity of growth arrest and DNA damage-inducible protein 45 (GADD45). This was accompanied by increased p21 expression, which resulted in reversible growth arrest at the G0/G1 phase of ECs and inhibition of proliferation [153] (Fig. 4c). Considering the context-dependent effect of p53, its induction of growth arrest could also protect ECs from apoptosis in response to undisturbed flow.

As a response to DNA damage, p53 triggers the telomere dysfunction-mediated senescence of VSMCs via the p53-inducible E3 ubiquitin ligase Siah-1. Siah-1 accumulation mediated the ubiquitination and degradation of telomeric repeat-binding factor-2 (TRF2). This decreased TRF2 expression directed telomere dysfunction by reducing telomere binding, which mediated senescence of VSMCs accompanied by increased DNA damage and decreased DNA repair (Fig. 4c) [154, 155]. Moreover, p53 is known as a downstream effector of the TRF2-ATM-p53 pathway [156], and this positive feedback loop may amplify telomere dysfunction-mediated cellular responses.

p53 also exerts its regulatory proliferative and senescence functions in cardiac fibroblasts. These are associated with cardiac fibrosis and therefore contribute to cardiac remodeling. Burke et al. reported that in a heart failure model, small proline-rich protein 2b (Sprr2b), the expression of which was confined to cardiac fibroblasts, played a critical role in regulating fibroblast proliferation by targeting p53, which then contributed to fibrosis. In a pressure-overload cardiac dysfunction mouse model, Sprr2b expression was increased and thus induced p53 degradation by acting as a regulatory subunit of the USP7/MDM2-containing ubiquitination complex. As target genes, the expression of upregulated cyclin-dependent kinases and promitotic cyclins and downregulated cyclin-dependent kinase inhibitors were consistent with decreased p53 expression, which triggered fibroblast proliferation and subsequent cardiac fibrosis [157]. The ability of p53 to regulate cardiac fibroblast proliferation and senescence has also been demonstrated in laminopathies associated with models of dilated cardiomyopathy, ischemia, and hypertrophy [58, 158–160]. It also regulates cell cycle arrest in non-myocytes, but this mechanism remains to be further elucidated.

Others

Some studies have indicated that p53 regulates the transdifferentiation process in epithelial-mesenchymal transition (EMT) and mesenchymal-endothelial transition (MEndoT). However, the mechanism by which p53 regulates transdifferentiation is unclear. Zhang et al. revealed that increased p53 activation, induced by Mdm2/Mdm4 deletion, was associated with defects in endocardial cushion morphogenesis. These defects occurred by disrupting the normal EMT of ECs and the post-EMT proliferation of mesenchymal cells, an important step in septum and valve development for forming the four-chambered heart [13]. Intriguingly, p53 overexpression, especially in cardiac fibroblasts, is favorable for MEndoT in both in vitro and in vivo cardiomyocytes after acute ischemic cardiac injury. During MEndoT, fibroblasts adopt an EC-like phenotype, thereby generating de novo ECs in the injured heart. In MEndoT, p53 is a necessary transcription factor and binds the promoters of HOXA9 and HOXD3, which play important roles in endothelial differentiation. The overexpression of p53 observed in cardiac fibroblasts stimulates de novo capillary generation in the injury region, accompanied by a decrease in collagen deposition, without increasing apoptosis in myocytes [161].

Additionally, p53 regulates the expression of genes associated with cardiac architecture. Mak et al. detected unfavorable changes in gene expression in Tp53 deletion mice, which regulated the expression of genes related to cardiac architecture. These included those associated with the Z disk (Actn1, Cx43, Itgb1bp2), sarcomere (Mylk3, Tnnc1, Ttn), and extracellular matrix (Col1a1, Col3a1, Fn1) [14].

Potential therapeutic targets of p53 in CVDs

Pifithrin-α, a small molecule inhibitor of p53, was isolated by Komarov et al. to reduce side effects associated with radio- and chemotherapy induced by p53-mediated apoptosis [162]. It reversibly inhibits p53 transcription activity, leading to subsequent suppression of the transcription of p53 target genes, including Ccng1, Bax, Hras, and Mdm2 [163]. However, in some doxorubicin-treated cancer cell lines, pifithrin-α modifies p53 post-translation by inhibiting p53 phosphorylation at Ser33 and Ser15 [164]. This molecular mechanism requires further exploration in future studies. In contrast to pifithrin-α, pifithrin–μ inhibits p53 in the cytoplasm by directly impending its interaction with mitochondria, resulting in decreased cytochrome c release, caspase-3 activation, and apoptosis [165]. The usage of pifithrin as a p53 inhibitor in CVDs is summarized in Table 1.

Table 1.

The application of pifithrin as a p53 inhibitor in CVDs

Inhibitor	Dose	Frequency	Mice/cell	Model	P53 target	Molecular Effect	Reference
PFT-α	Total 4.4 mg/kg	30 minutes before and 3 hours after doxorubicin	ICR mice	Doxorubicin -induced cardiotoxicity	Bax and MDM2	Anti-apoptosis	[33]
PFT-α	20 μM	1 hour before doxorubicin	H9c2 cells and neonatal Sprague-Dawley rat cardiomyocytes	Doxorubicin -induced cardiotoxicity	Bax, PUMA, Bcl-2	Anti-apoptosis	[166]
PFT-α	30 μM	Before doxorubicin	H9c2 myoblasts	Doxorubicin -induced cardiotoxicity	Bax	Anti-apoptosis	[167]
PFT-α	2.2 mg/kg	40 minutes before ischemia	Twenty-month-old male F344 rats	Ischemia/reperfusion injury	Bax and Bcl-2	Anti-apoptosis	[168]
PFT-α	10 μM	Not mentioned	Ventricular cardiomyocyte from newborn rat	H2O2-oxidative stress	Apaf-1	Anti-apoptosis	[173]
PFT-α	2.2 μg/g or 4.4 μg/g	24 hours after LAD-ligation, daily day1-6	Adult male mice	Ischemia	Caspase-3, apaf-1	Anti-apoptosis	[173]
					MMP-2	Degradation of extracellular collagen matrix
PFT-α	2.2 μg/g	Post-natal day 9-15	mTORcm KO mice with C57BL/6:FVB/N.background	Dilated cardiomyopathy	Caspase-3	Anti-apoptosis	[170]
PFT-α	100 μM	Pre-treatment	H9c2 rat cardiomyoblasts	Glucolipotoxicity	Caspase-3;NQO1	Anti-apoptosis	[171]
PFT-α	1.1 mg/kg	5 times/week for 2 months	FVB male	Diabetic cardiomyopathy	Bax, Bcl-2, AIF	Anti-apoptosis	[31]
					p16INK4A; p21WAF1/CIP	Anti-senescence
					Hif-1α	Angiogenesis
					GLUT-1 and GLUT4	Glucose uptake
PFT-μ	3 mg/kg	2 days/3 weeks	Male ICR/CD-1 mice	Aging	Not mentioned	Increased mtDNA content; COX subunits and assembly proteins	[172]

In doxorubicin-induced cardiotoxicity, pifithrin-α rescued apoptosis-related alterations to the heart architecture and cardiac dysfunction by attenuating elevated Bax and MDM2 protein levels without changing the levels of p53 and its phosphorylated form [33]. Consistent with this, an in vitro study revealed that pifithrin-α attenuated doxorubicin-induced H9c2 cell apoptosis by downregulating Bax, PUMA-α, and cleaved caspase-3, in addition to blocking the reduction of Bcl-2 protein [166, 167]. Additionally, pifithrin-α attenuated the increase of phospho-p53 protein and its nuclear translocation [166]. Also, pifithrin-α partially reversed p53-independent apoptosis by blocking p42/p44ERK and p46/p54JNK activation in doxorubicin-treated myoblastic H9c2 cells [52].

Pifithrin-α has been gradually implemented in other CVD models. Gu et al. demonstrated that in an in vivo diabetic cardiomyopathy model, pifithrin-α restored senescence, impaired angiogenesis, and reduced glycolysis by inhibiting p53-dependent target gene transcription (involving p21, p16, HIF-1α, GLUT-1, and GLUT-4) [31]. In an ischemia/reperfusion rat model, pifithrin-α attenuated cardiomyocyte apoptosis accompanied by the reduction of the p53-mediated increase in the ratio of Bax to Bcl-2, which rescued cardiac dysfunction [168, 169]. Pifithrin-α also exerted an anti-apoptotic effect by targeting p53 in a model of dilated cardiomyopathy and in vitro glucolipotoxicity [170, 171]. Furthermore, pifithrin-α restored NAD(P)H dehydrogenase quinone 1 (NQO1) expression by inhibiting p53-dependent activation at the transcriptional level, and the anti-oxidative activity of NQO1 decreased p53-dependent apoptosis [171]. In aged mice, pifithrin–μ blocked the binding of p53 to mitochondria, which increased mitochondrial cytochrome c oxidase complex (COX) biogenesis [172]. Consistently, Zhang et al. demonstrated that pifithrin-α reduced cardiomyocyte apoptosis in an ischemic model by targeting caspase-3 and apaf-1. Intriguingly, mice treated with pifithrin-α after coronary ligation had increased infarct size and showed higher mortality, which may be associated with elevation of pifithrin-α-induced and p53-dependent matrix metalloproteinase (MMP)-2 activity [173]. In an ischemic/reperfusion model, MMP-2 proteolyzed troponin I, titin, myosin light chain-1, and α-actinin, all of which are essential for maintaining cardiac structure and function [174–178]. The paradoxical result of this paper compared to other findings may be attributed to the timing of pifithrin-α administration, which was administered after and not before ischemic injury. Furthermore, it should be noted that the model of coronary ligation without reperfusion can only mimic a very small proportion of clinical cases because of the development of reperfusion technology and spontaneous recanalization. Considering the paradoxical effect of pifithrin in cardiomyopathy, our incomplete understanding of its mechanism, p53-independent regulation, and its potential to alter tumor growth, more preclinical studies should be conducted to identify the effect of pifithrin treatment on p53-mediated cardiomyopathy.

Recently, Saleme et al. identified pyruvate kinase muscle 2 (PKM2) as a potential target of p53-mediated doxorubicin-related cardiotoxicity [36]. Taking into consideration the redox-regulated PKM2-p53 interaction and different redox states in heart and tumor tissues from the same doxorubicin-treated animal, animals were treated with TEPP-46, a compound that stabilizes tetrameric PKM2. Under the state of high oxidation in the heart, stabilized tetrameric PKM2 downregulated p53 transcriptional activity and doxorubicin-induced cardiomyocyte apoptosis and prevented cardiac dysfunction. The opposite effect was observed under the state of low oxidation in the tumor.

Conclusion and perspective

We have summarized how p53 is critical for maintaining physiological function and carrying out pathological processes in CVDs. As p53 regulates metabolism and the expression of cardiac architecture-related proteins, basal p53 activity is necessary to maintain normal cardiac architecture and function. It also regulates the progress of CVDs via anti-angiogenesis, pro-apoptosis, pro-autophagy, pro-necrosis, metabolism regulation, and cell cycle arrest regulation. It plays different roles in cardiomyocytes and non-myocytes. Primarily, p53 determines the fates of cardiomyocytes by regulating metabolism and programmed cell death. It regulates cell cycle arrest and angiogenesis in non-myocytes, thus participating in the regulation of CVDs. The mechanisms underlying the different regulatory roles of p53 in cardiomyocytes and non-myocytes in the same model warrant further studies. Although pifithrin is widely used as a p53 inhibitor in animal models of CVDs, its efficacy as a potential therapy for targeting p53 requires further investigation to identify its p53-independent effect. Considering the cardioprotective and anticancer effects of targeting PKM2-p53 interaction in the same doxorubicin-treated cancer model, PKM2 may provide a new target for future p53-mediated chemotherapy-induced cardiotoxicity and other CVD models. Further studies are required to determine whether this is a viable option for clinical use.

Author contributions

HM: Conceptualization and Writing—Original draft preparation. HC, QC, WZ, XW, and SH: Literature searching and summary and Writing—Original draft preparation. YZ: Conceptualization, Reviewing and Editing, and Funding acquisition. LC: Conceptualization, Reviewing, and Editing.

Funding

This work was supported in part by the National Key R&D Program of China (2016YFC0900903 to Yang Zheng). All personnel expenses and partial research-related expenses for Hongbo Men, Wenqian Zhou, Xiang Wang, and Shan Huang when they worked in the University of Louisville (11/2018–3/2021) were provided by the First Hospital of Jilin University, Changchun, China under the agreement of U.S-China Pediatric Research Exchange Training Program.

Compliance with ethical standards

Conflict of interest

The author declares no conflict of interest.

Consent for publication

Its publication has been approved by all co-authors.