The natural process of aging in humans often increases one’s risk for a number of chronic diseases, including type 2 diabetes (T2D), dyslipidemia, hypertension, and cardiovascular disease (CVD). It is increasingly recognized that aging-related CVD in the absence of other confounding risk factors, such as obesity and T2D, has unique features. Although aging is accompanied by various molecular and physiological changes ultimately affecting whole-body homeostasis, alterations in myocardial energy metabolism are a common hallmark of CVD in elderly people. Under normal physiological conditions, the hearts of healthy individuals oxidize fatty acids, glucose, ketones, and amino acids to meet their energy demand. However, the relative contribution of these fuels for myocardial energy production changes during aging, including a decrease in fatty acid oxidation and an increase in overall glucose utilization (glucose uptake and glycolysis in particular). The heart is also associated with mitochondrial structural and functional abnormalities, resulting in the accumulation of reactive oxygen species and redox-regulated signaling that can exacerbate damage to oxidative phosphorylation capacity and aggravate cardiac dysfunction. We herein discuss the primary changes in myocardial energy metabolism and mitochondrial structure and function, as well as alterations in key molecular mediators that ensue during the physiological process of aging, while considering their potential impact on cardiac function. We have also highlighted the need for comprehensive clinical trials of potential lifestyle or established pharmacological interventions to attenuate myocardial energy metabolism and improve cardiac health in the setting of aging, which may lead to a healthy lifespan.

BackgroundDespite extensive study, the structural, metabolic, and mechanistic heterogeneity amongst polyunsaturated fatty acids (PUFA) have confounded identification of their molecular targets and roles in cardiovascular diseases. Previously our group demonstrated that the cardioprotective properties of both 19,20-epoxydocosapentaenoic acid (EDP), a CYP450-derived metabolite of docosahexaenoic acid (DHA), and a synthetic structural analog SA-22, were SIRT3-dependent. Thus, we explored the impact of this signaling on mitochondrial homeostasis in the context of hypoxic myocardial injury. SA-22 ligand binding was confirmed via SYPRO Orange thermal shift assay.MethodologySIRT3 catalytic activity was measured using an acetylated HDAC fluorogenic substrate assay. Point mutagenesis experiments confirmed the involvement of residue SER149. H9c2 cells were used as an in vitro model of hypoxia/reoxygenation (HR) injury. Cells were deprived of oxygen for 24 h followed by a 6-h reoxygenation period wherein cells were treated with either vehicle, 19,20-EDP (1 µM), or SA-22 (1 µM), either with the pan-sirtuin inhibitor nicotinamide (NAM) (30 µM), or the SIRT3-selective inhibitor 3-(1H-1,2,3-triazol-4-yl)-pyridine (3-TYP) (50 µM). Mitophagy was assessed via the pH-dependent fluorescent mitochondrial autophagy reporter protein (mito-Keima). Mitochondrial respiration was measured using high-resolution respirometry (Oroboros-O2K).ResultsAddition of SA-22 altered SYPRO Orange fluorescence and improved catalytic activity in vitro but was abrogated by SER149 substitution, indicating that SA-22 is a positive allosteric modulator of SIRT3. Lastly, SA-22 protected cardiac cells against HR-induced changes in mitophagy and mitochondrial respiration in a SIRT3-dependent manner.ConclusionIn conclusion, SA-22 directly binds and enhances the activity of SIRT3, preserving cardiac mitochondrial homeostasis despite myocardial hypoxia-reoxygenation injury.

The differentiation of HL-60 cells into neutrophil-like cells is widely used to study neutrophil functions, yet no comprehensive proteomic analysis has been conducted on dimethylformamide (DMF)-induced differentiation. This study provides the first detailed proteomic characterization of DMF-differentiated (df)-HL-60 cells, demonstrating its distinct molecular and functional profiles compared to the well-established dimethyl sulfoxide (DMSO)-df-HL-60 cell model. HL-60 cells were differentiated using 1.25% DMSO or 70 mM DMF for five days. Cell proliferation, granulocytic differentiation (CD11b expression), superoxide anion production, myeloperoxidase (MPO) protein expression and enzymatic activity, and neutrophil extracellular trap (NET) formation were evaluated. Proteomic profiling was performed using LC-MS/MS, followed by gene ontology and pathway enrichment analysis to identify key molecular changes associated with differentiation. DMF-df-HL-60 cells maintained higher proliferation rates than DMSO-df-HL-60 cells. Both agents successfully induced granulocytic differentiation, with DMSO producing greater CD11b expression. Functionally, both differentiation methods enhanced superoxide anion production, but DMF-df-HL-60 cells generated distinct superoxide radical spectra when evaluated with EPR spectroscopy. MPO protein expression and activity were significantly reduced in both differentiation models, indicating a transition to a mature neutrophil-like phenotype. Proteomic analysis revealed that neutrophil degranulation was the most significantly enriched pathway in DMF-df-HL-60 cells, alongside pathways involved in oxidant production and receptor tyrosine kinase signaling. Furthermore, S100 calcium-binding protein A9 (S100A9) abundance was significantly higher in DMF-df-HL-60 cells, suggesting a novel role of DMF in modulating neutrophil differentiation. DMF-df-HL-60 cells also showed activation of MAPK, Ras, and Rap1 signaling pathways, similar to the DMSO-df-HL-60 cell model, which is crucial for differentiation and immune responses. DMF-df-HL-60 cells generated more NETs than the DMSO-df-HL-60 cell model with phorbol myristate acetate. This study emphasizes the importance of selecting the appropriate differentiation model to accurately mimic neutrophil biology and highlights DMF's unique role in neutrophil differentiation, providing novel insights into differentiation-induced functional adaptations.

Abstract Background: During prediabetes, increased free fatty acid levels induce negative actions on cardiomyocytes, but effective approaches to prevent these negative actions and the development of diabetic cardiomyopathy are limited. Saturated fatty acids such as palmitate have been shown to contribute to the development of diabetic cardiomyopathy (DbCM), with ferroptosis being recognized as a potential mechanism of palmitate-induced cardiac injury. ALOX15 is a driving factor of ferroptosis and also contributes to inflammation and oxidative stress in DbCM. Baicalein is a natural inhibitor of ALOX15, but the effects of baicalein on ferroptosis in DbCM remain unknown. Aims and Objectives: The overall objective of the present study was to elucidate the potential effects of baicalein on ferroptosis in cardiomyocytes when exposed to elevated free fatty acid levels. Materials and Methods: H9c2 cardiomyocytes were treated with palmitic acid at different concentrations to induce lipid peroxidation and ferroptosis-related responses. The cells were subsequently incubated with baicalein to evaluate its protective effects. Lipid peroxidation and intracellular reactive oxygen species (ROS) levels were measured. Production of 12- and 15-hydroxyeicosatetraenoic acid (15-HETE), as well as mitochondrial function indicators including mitochondrial membrane potential, cytochrome c release, and mitochondrial ROS, were assessed. Protein expression levels of GPX4, ACSL4, and ALOX15 were analyzed by Western blot. Statistical analysis was performed to determine concentration-dependent effects and treatment efficacy. Results: Our results revealed that 12-, 15-HETE production, lipid peroxidation and intracellular reactive oxygen species (ROS) levels increased in a concentration-dependent manner when treated with palmitic acid. Baicalein effectively inhibited the ALOX15 associated 12-, 15- HETEs production and decreased lipid peroxidation in H9c2 cells. Furthermore, baicalein also ameliorated mitochondrial dysfunction through restoring mitochondrial membrane potential and decreasing the release of cytochrome c, as well as mitochondrial ROS. Treatment with baicalein also increased GPX4 and reduced ACSL4 and ALOX15 protein expression in H9c2 cells. Conclusions: These results suggest that baicalein may protect cardiomyocytes against ferroptosis through an ACSL4-ALOX15-GPX4 axis.

Abstract Background Atherosclerotic cardiovascular disease (ASCVD) is the leading cause of morbidity and mortality worldwide. Despite effective lipid‐lowering treatments, substantial residual risks remain. In atherosclerosis, vascular smooth muscle cells (SMCs) undergo dedifferentiation, promoting disease progression. Membrane‐type I matrix metalloproteinase (MT1‐MMP/MMP14) promotes SMC dedifferentiation. However, the effect of inhibiting MMP14 in adults, particularly those with existing atherosclerotic plaques, is unclear. Methods We developed an inducible conditional SMC‐specific MMP14 knockout mouse model. Cardiac and vascular function were assessed using echocardiography and wire myography, respectively. Atherosclerosis progression and regression were evaluated in Ldlr−/− mice with or without MMP14 deficiency. snRNA‐seq of the aortas from Ldlr−/− mice was performed to determine the effect on SMC populations. Results MMP14 expression was elevated in SMCs within fibroatheroma compared with the pathological intima thickening in coronary aortas from patients with ASCVD. Conditional knockout of SMC MMP14 in adult mice did not change plasma cholesterol levels or basic cardiac and vascular function. However, atherosclerosis development was reduced, and the regression of existing plaques was enhanced in Ldlr−/− mice lacking SMC MMP14. snRNA‐seq revealed increased fibroblast‐like SMCs and reduced foam cell‐like SMCs in MMP14‐deficient Ldlr−/− mice compared to Ldlr−/− mice. Furthermore, SMC MMP14 deficiency decreased SMC proliferation and migration, accompanied by reduced platelet‐derived growth factor receptor (PDGFR) β levels and attenuated PDGF signalling. Conclusion SMC MMP14 promotes atherosclerosis in adult mice, likely through reducing PDGF signalling and inhibiting SMC migration and proliferation.

BACKGROUND AND PURPOSE:Treatment of cancer patients with anthracyclines is known to cause dose-dependent cardiotoxicity through several mechanisms including enhanced oxidative stress, ultimately resulting in defective excitation-contraction coupling. Loss of junctophilin-2 (JPH-2), which tethers transverse tubules (T-tubules) to the sarcoplasmic reticulum, is a feature of doxorubicin-induced cardiotoxicity, yet the protease involved in unclear. As activation of matrix metalloproteinase-2 (MMP-2) is known to contribute to doxorubicin-induced cardiotoxicity, we investigated here the role of MMP-2 in JPH-2 proteolysis and defective calcium transients in it. EXPERIMENTAL APPROACH:C57BL/6J mice were treated with doxorubicin for 4 weeks with or without the MMP inhibitor (doxycycline), MMP-2 preferring inhibitor (ONO-4817) or vehicle, and cardiac function was assessed using echocardiography. JPH-2 levels in ventricular extracts were measured. Calcium transients and JPH-2 levels were measured in neonatal rat ventricular cardiomyocytes treated with doxorubicin and ONO-4817. KEY RESULTS:Both MMP inhibitors attenuated doxorubicin-induced cardiac systolic and diastolic dysfunction. Doxorubicin treatment resulted in JPH-2 cleavage in mouse hearts as evidenced by the appearance of lower molecular weight products of 63 and 25 kDa, which was prevented by MMP inhibitors. Loss of JPH-2 and impaired calcium transients were observed in neonatal rat ventricular cardiomyocytes treated with doxorubicin, while ONO-4817 attenuated these changes. In silico analysis predicted cleavage sites between JPH-2 MORN repeats and within its unstructured region. CONCLUSIONS AND IMPLICATIONS:These results reveal that JPH-2 proteolysis is a consequence of MMP-2 activation and highlight the beneficial prophylactic action of two orally available MMP inhibitors in preventing doxorubicin-induced cardiotoxicity.

Age-related structural and functional deterioration of the kidneys is common among elderly individuals and contributes to increased mortality and morbidity. Mitochondrial dysfunction and cellular senescence are two hallmarks of aging that drive a progressional renal decline; however, the underlying molecular mechanisms and endogenous regulators behind these processes remain incompletely understood. The metabolism of polyunsaturated fatty acids by CYP450 enzymes produces numerous bioactive lipid mediators that can be further metabolized by soluble epoxide hydrolase (sEH) and microsomal epoxide hydrolase (mEH) into diol metabolites, often with reduced biological effects. The objective of this study was to assess renal mitochondrial alterations and cellular senescence in young and aged wild-type (WT) and sEH-deficient (sEH null) female mice. We found aged sEH null mice exhibited better physiological health, as reflected by lower frailty index scores and reduced circulating levels of GDF-15 levels, creatinine, and urea nitrogen. Notably, the expression of both sEH and mEH was significantly elevated in aged WT kidneys, accompanied by increased expression of the kidney injury marker (Kim-1) and evidence of structural abnormalities. In contrast, sEH deletion attenuated the age-related upregulation of senescence markers (p53, p21, p16) and SASP components (MCP-1, IL-1β, and caspase-1), as well as the inflammatory zBP1 expression and downstream interferons. Additionally, sEH deletion preserved age-related disruption of mitochondrial dynamics, content, and respiratory function. Together, these data suggest that sEH deletion confers renoprotective effects in aging, characterized by improved systemic health, reduced renal injury and inflammation as preserves mitochondrial integrity and function.

Pancreatic ductal adenocarcinoma (PDAC) cells exhibit high metabolic flexibility, enabling survival under glucose limitation by using alternative fuels such as fatty acids. Lipophagy, a selective form of autophagy targeting lipid droplets (LDs), supports mitochondrial respiration during such nutrient stress. Our previous study demonstrated that the LSD1 inhibitor SP-2509 disrupts lipophagy independently of LSD1 inhibition, leading to LD accumulation and ATP depletion in glycolysis-suppressed PDAC cells. However, the effects of disrupted lipid homeostasis on mitochondrial function remained unclear. Here, the effects of lipid overload on mitochondrial morphology and activity were investigated under glucose-restricted conditions. SP-2509 treatment caused substantial LD accumulation with mitochondrial fragmentation and closer LD-mitochondrion spatial proximity, forming peridroplet mitochondria (PDM)-like structures. These structures were not associated with increased fatty acid oxidation; instead, they correlated with impaired mitochondrial respiration, shown by a reduced complex II/IV activity ratio. Forced mitochondrial fission alone did not reduce ATP production, suggesting lipid metabolic disruption, rather than morphological changes, drives mitochondrial dysfunction. Moreover, mitochondria relocated from perinuclear to peripheral regions following treatment, a shift associated with reduced cell viability and indicating a possible link between nuclear-mitochondrial proximity and survival under stress. Our findings challenge the prevailing view of PDM as inherently adaptive organelles. In PDAC, aberrant PDM formation under lipid stress may represent a maladaptive response contributing to metabolic vulnerability. This newly identified dysregulation of lipid and mitochondrial homeostasis may offer a new therapeutic target in treatment-resistant pancreatic cancer.

INTRODUCTION:Cardiac energy metabolism is disrupted in heart failure with preserved ejection fraction (HFpEF), as characterized by a switch from glucose oxidation towards fatty acid oxidation. However, although oxidation of ketones is an important source of ATP it remains unclear how the heart oxidizes ketones in HFpEF. It is also unclear whether elevating ketone supply to the heart can improve cardiac energetics and/or provide functional benefit for the hearts in HFpEF. AIMS:The present study investigated the effects of increasing ketone supply to the heart via ketone supplementation or SGLT2 inhibitor treatment in a mouse model of HFpEF. METHODS:HFpEF was induced in 13-month-old C57BL/6N female mice with 60% high-fat diet and L-NAME (0.5 g/L/day in the drinking water) for 6 weeks. In parallel, two other groups of mice were maintained on the HFpEF protocol while also receiving either a ketone ester supplement (1-3 butanediol 1 g/kg/day) or SGLT2 inhibitor (empagliflozin 10 mg/kg/day) for 6 weeks. Control mice were fed with regular low-fat diet and regular drinking water. Hearts of the mice were excised and perfused in the isolated working mode aerobically with 5-mM glucose, 0.8-mM palmitate, 100-μU/mL insulin, with either low (0.6 mM) or high (1 mM) levels of β-hydroxybutyrate. Metabolic rates of the hearts were measured with radiolabelled [U-14C] glucose, [9,10-3H] palmitate and [3-14C] β-hydroxybutyrate. RESULTS:In HFpEF mouse hearts, glucose oxidation was significantly decreased with a parallel increase in fatty acid oxidation. Increasing β-hydroxybutyrate levels from 0.6 to 1 mM in the perfusate resulted in a rise in ketone oxidation rates in control hearts (from 861 ± 63 to 1377 ± 94 nmol g dry wt-1 min-1), which was muted in HFpEF hearts (from 737 ± 68 to 897 ± 134 nmol g dry wt-1 min-1). Following ketone ester supplement or SGLT2 inhibitor treatment, HFpEF mice presented with restored ketone oxidation rates (from 674 ± 36 to 1181 ± 115 nmol g dry wt-1 min-1 with ketone ester supplement and from 797 ± 121 to 1240 ± 120 nmol g dry wt-1 min-1 with SGLT2i). Yet, this was not associated with improvement in cardiac function. CONCLUSIONS:In HFpEF mice, the heart switches from glucose oxidation to fatty acid oxidation, with ketone oxidation being impaired. Increasing ketone supply to the heart via ketone ester supplementation or SGLT2 inhibitor treatment increases myocardial ketone oxidation rates but was not associated with functional improvements. Unlike HFrEF, ketone supplementation strategies may be less effective in HFpEF due to an impairment of myocardial ketone oxidation in HFpEF.

AIMS:Although current clinical therapies following myocardial infarction (MI) have improved patient outcomes, morbidity, and mortality rates, secondary to ischaemic and ischaemia reperfusion (IR) injury remains high. Maintaining mitochondrial quality is essential to limit myocardial damage following cardiac ischaemia and IR injury. The mitochondrial deacetylase sirtuin 3 (SIRT3) plays a pivotal role in regulating mitochondrial function and cardiac energy metabolism. In the current study, we hypothesize that 19,20-epoxydocosapentaenoic acid (19,20-EDP) attenuates cardiac IR injury via stimulating mitochondrial SIRT3. METHODS AND RESULTS:Ex vivo models of isolated heart perfusions were performed in C57BL/6 mice to assess the effect of 19,20-EDP on cardiac function and energy metabolism following IR injury. In vivo permanent occlusion of the left anterior descending coronary artery was performed to induce MI; mice were administered 19,20-EDP with or without the SIRT3 selective inhibitor 3-TYP. Mitochondrial SIRT3 targets and respiration were assessed in human left ventricular tissues obtained from individuals with ischaemic heart disease (IHD) and compared to non-failing controls (NFCs). Binding affinity of 19,20-EDP to human SIRT3 was assessed using molecular modelling and fluorescence thermal shift assay. Results demonstrated that hearts treated with 19,20-EDP had improved post-ischaemic cardiac function, better glucose oxidation rates, and enhanced cardiac efficiency. The cardioprotective effects were associated with enhanced mitochondrial SIRT3 activity. Interestingly, treatment with 19,20-EDP markedly improved mitochondrial respiration and SIRT3 activity in human left ventricle (LV) fibres with IHD compared to NFC. Moreover, 19,20-EDP was found to bind to the human SIRT3 protein enhancing the NAD+-complex stabilization leading to improved SIRT3 activity. Importantly, the beneficial effects of 19,20-EDP were abolished by SIRT3 inhibition or using the S149A mutant SIRT3. CONCLUSION:These data demonstrate that 19,20-EDP-mediated cardioprotective mechanisms against ischaemia and IR injury involve mitochondrial SIRT3, resulting in improved cardiac efficiency.

12,13-dihydroxy-9z-octadecenoic acid (12,13-DiHOME) is a linoleic acid diol derived from cytochrome P-450 (CYP) epoxygenase and epoxide hydrolase (EH) metabolism. 12,13-DiHOME is associated with inflammation and mitochondrial damage in the innate immune response, but how 12,13-DiHOME contributes to these effects is unclear. We hypothesized that 12,13-DiHOME enhances macrophage inflammation through effects on NOD-like receptor protein 3 (NLRP3) inflammasome activation. To test this hypothesis, we utilized human monocytic THP1 cells differentiated into macrophage-like cells with phorbol myristate acetate (PMA). 12,13-DiHOME present during lipopolysaccharide (LPS)-priming of THP1 macrophages exacerbated nigericin-induced NLRP3 inflammasome activation. Using high-resolution respirometry, we observed that priming with LPS+12,13-DiHOME altered mitochondrial respiratory function. Mitophagy, measured using mito-Keima, was also modulated by 12,13-DiHOME present during priming. These mitochondrial effects were associated with increased sensitivity to nigericin-induced mitochondrial depolarization and reactive oxygen species production in LPS+12,13-DiHOME-primed macrophages. Nigericin-induced mitochondrial damage and NLRP3 inflammasome activation in LPS+12,13-DiHOME-primed macrophages were ablated by the mitochondrial calcium uniporter (MCU) inhibitor, Ru265. 12,13-DiHOME present during LPS-priming also enhanced nigericin-induced NLRP3 inflammasome activation in primary murine bone marrow-derived macrophages. In summary, these data demonstrate a pro-inflammatory role for 12,13-DiHOME by enhancing NLRP3 inflammasome activation in macrophages.

OMT-28 is a metabolically robust small molecule developed to mimic the structure and function of omega-3 epoxyeicosanoids. However, it remained unknown to what extent OMT-28 also shares the cardio-protective and anti-inflammatory properties of its natural counterparts. To address this question, we analyzed the ability of OMT-28 to ameliorate hypoxia/reoxygenation (HR)-injury and lipopolysaccharide (LPS)-induced endotoxemia in cultured cardiomyocytes. Moreover, we investigated the potential of OMT-28 to limit functional damage and inflammasome activation in isolated perfused mouse hearts subjected to ischemia/reperfusion (IR) injury. In the HR model, OMT-28 (1 μM) treatment largely preserved cell viability (about 75 vs. 40 % with vehicle) and mitochondrial function as indicated by the maintenance of NAD+/NADH-, ADP/ATP- and respiratory control ratios. Moreover, OMT-28 blocked the HR-induced production of mitochondrial reactive oxygen species. Pharmacological inhibition experiments suggested that Gαi, PI3K, PPARα, and Sirt1 are essential components of the OMT-28 mediated pro-survival pathway. Counteracting inflammatory injury of cardiomyocytes, OMT-28 (1 μM) reduced LPS-induced increases in TNFα protein (by about 85 % vs vehicle) and NF-κB DNA binding (by about 70 % vs. vehicle). In the ex vivo model, OMT-28 improved post-IR myocardial function recovery to reach about 40 % of the baseline value compared to less than 20 % with vehicle. Furthermore, OMT-28 (1 μM) limited IR-induced NLRP3 inflammasome activation similarly like a direct NLRP3 inhibitor (MCC950). Overall, this study demonstrates that OMT-28 possesses potent cardio-protective and anti-inflammatory properties supporting the hypothesis that extending the bioavailability of omega-3 epoxyeicosanoids may improve their prospects as therapeutic agents.

Supplemental Digital Content is Available in the Text. Mounting evidence suggests that cytochrome P450 epoxygenase-derived metabolites of docosahexaenoic acid, called epoxydocosapentaenoic acids (EDPs), limit mitochondrial damage after cardiac injury. In particular, the 19,20-EDP regioisomer has demonstrated potent cardioprotective action. Thus, we investigated our novel synthetic 19,20-EDP analog SA-22 for protection against cardiac ischemia-reperfusion (IR) injury. Isolated C57BL/6J mouse hearts were perfused through Langendorff apparatus for 20 minutes to obtain baseline function, followed by 30 minutes of global ischemia. Hearts were then treated with vehicle, 19,20-EDP, SA-22, or SA-22 with the pan-sirtuin inhibitor nicotinamide or the SIRT3-selective inhibitor 3-(1H-1,2,3-triazol-4-yl) pyridine (3-TYP) at the start of 40 minutes reperfusion (N = 5-8). We assessed IR injury-induced changes in recovery of myocardial function, using left ventricular developed pressure and systolic and diastolic pressure change. Tissues were assessed for electron transport chain function, SIRT1 and SIRT3, optic atrophy type 1, and caspase-1. We also used H9c2 cells in an in vitro model of hypoxia/reoxygenation injury (N = 3-6). Hearts perfused with SA-22 had significantly improved postischemic left ventricular developed pressure, systolic and diastolic recovery (64% of baseline), compared with vehicle control (15% of baseline). In addition, treatment with SA-22 led to better catalytic function observed in electron transport chain and SIRT enzymes. The protective action of SA-22 resulted in reduced activation of pyroptosis in both hearts and cells after injury. Interestingly, although nicotinamide cotreatment worsened functional outcomes, cell survival, and attenuated sirtuin activity, it failed to completely attenuate SA-22-induced protection against pyroptosis, possibly indicating EDPs exert cytoprotection through pleiotropic mechanisms. In short, these data demonstrate the potential of our novel synthetic 19,20-EDP analog, SA-22, against IR/hypoxia-reoxygenation injury and justify further development of therapeutic agents based on 19,20-EDP.

Although increased aerobic glycolysis is common in various cancers, pancreatic ductal adenocarcinoma (PDAC) cells can survive a state of glycolysis suppression. We aimed to identify potential therapeutic targets in glycolysis-suppressed PDAC cells. By screening anticancer metabolic compounds, we identified SP-2509, an inhibitor of lysine-specific histone demethylase 1A (LSD1), which dramatically decreased the growth of PDAC PANC-1 cells and showed an anti-tumoral effect in tumor-bearing mice. The growth of glycolysis-suppressed PANC-1 cells was also inhibited by another LSD1 inhibitor, OG-L002. Similarly, the other two PDAC cells (PK-1 and KLM-1) with suppressed glycolysis exhibited anticancer effects against SP-2509. However, the anticancer effects on PDAC cells were unrelated to LSD1. To investigate how PDAC cells survive in a glycolysis-suppressed condition, we conducted proteomic analyses. These results combined with our previous findings suggested that glucose-starvation causes PDAC cells to enhance mitochondrial oxidative phosphorylation. In particular, mitochondrial fatty acid metabolism was identified as a key factor contributing to the survival of PDAC cells under glycolysis suppression. We further demonstrated that SP-2509 and OG-L002 disturbed fatty acid metabolism and induced lipid droplet accumulation through the impairment of lipophagy, but not bulk autophagy. These findings indicate a significant potential association of lipophagy and anticancer effects in glycolysis-suppressed PDAC cells, offering ideas for new therapeutic strategies for PDAC by dual inhibition of glycolysis and fatty acids metabolism.

Cellular senescence is a condition characterized by stable, irreversible cell cycle arrest linked to the aging process. The accumulation of senescent cells in the cardiac muscle can contribute to various cardiovascular diseases (CVD). Telomere shortening, epigenetic modifications, DNA damage, mitochondrial dysfunction, and oxidative stress are known contributors to the onset of cellular senescence in the heart. The link between mitochondrial processes and cellular senescence contributed to the age-related decline in cardiac function. These include changes in mitochondrial functions and behaviours that arise from various factors, including impaired dynamics, dysregulated biogenesis, mitophagy, mitochondrial DNA (mtDNA), reduced respiratory capacity, and mitochondrial structural changes. Thus, regulation of mitochondrial biology has a role in cellular senescence and cardiac function in aging hearts. Targeting senescent cells may provide a novel therapeutic approach for treating and preventing CVD associated with aging. CYP epoxygenases metabolize N-3 and N-6 polyunsaturated fatty acids (PUFA) into epoxylipids that are readily hydrolyzed to diol products by soluble epoxide hydrolase (sEH). Increasing epoxylipids levels or inhibition of sEH has demonstrated protective effects in the aging heart. Evidence suggests they may play a role in cellular senescence by regulating mitochondria, thus reducing adverse effects of aging in the heart. In this review, we discuss how mitochondria induce cellular senescence and how epoxylipids affect the senescence process in the aged heart.