BACKGROUND:Iron homeostasis in heart is essential for maintaining cardiac function, but its precise role in iron metabolism and its specific function remain incompletely understood. METHODS AND RESULTS:We generated cardiomyocyte-specific Fbxl5 deficient mice (αMHC-Cre;Fbxl5F/F). Those mice showed increased IRP2 protein levels, which in cardiomyocytes undergoes Fbxl5-dependent degradation. Young (12-week-old) αMHC-Cre;Fbxl5F/F mice also showed upregulated levels of the IRP2, target transferrin receptor 1 (TfR1) and enhanced Fe3+ uptake into cardiomyocytes, increasing ferritin, total iron, and Fe2+ levels in cardiomyocytes. Fbxl5 deficiency increased both mitochondrial respiration capacity in isolated cardiac mitochondria and contractility of isolated cardiomyocytes, and in vivo, young αMHC-Cre;Fbxl5F/F mice showed augmented cardiac contractility and improved exercise tolerance. By contrast, in aged (24-month-old) αMHC-Cre;Fbxl5F/F mice, IRP2 levels were elevated relative to controls, but TfR1 upregulation and tissue iron accumulation were not seen. Accordingly, enhanced cardiac contractility and superior exercise tolerance phenotypes seen in young αMHC-Cre;Fbxl5F/F mice were absent in comparably aged mice, which unexpectedly exhibited pathological cardiac hypertrophy and upregulation of heart failure-associated genes. Furthermore, we found that administration of sodium-glucose cotransporter-2 inhibitors (SGLT2i), whose cardioprotective effects have recently been suggested to involve enhanced myocardial iron storage, improved cardiac performance without altering myocardial iron content, suggesting that SGLT2i exerts cardioprotective effects largely independent of cardiac iron metabolism. CONCLUSION:Cardiac iron dynamics are precisely regulated and tightly linked to cardiac function and prolonged dysregulation of iron dynamics can trigger cardiac pathological remodeling, even when iron balance is restored.

Mitochondria play a central role in cellular energy metabolism and homeostasis, and their dysfunction is closely linked to the progression of age-related diseases. The mitochondrial ubiquitin ligase MITOL (also known as MARCHF5) is a key regulator of mitochondrial dynamics and function, and reduced MITOL expression in the mouse heart has been implicated in mitochondrial dysfunction and cardiac aging. In this study, we identified berberrubine as a compound that promotes MITOL expression and activates mitochondria. We further assembled a group of berberrubine-based compounds, including its quinoid form and a newly developed water-soluble derivative, and collectively named them “Mitorubin” as mitochondria-activating compounds with therapeutic potential. While conventional berberrubine has poor water solubility, the addition of acetic acid significantly improved its solubility, enabling formulation as a solution. Mitorubin enhanced MITOL expression in cultured cells, increased mitochondrial DNA content and expression of mitochondrial proteins, and promoted mitochondrial respiration. In a model of age-related cardiac dysfunction, oral administration of Mitorubin restored mitochondrial function, improved cardiac performance, suppressed myocardial hypertrophy, and alleviated pulmonary congestion. Moreover, Mitorubin did not shorten lifespan in aged mice and significantly extended lifespan in high-fat diet-fed mice, suggesting both safety and efficacy under chronic administration. These findings suggest that Mitorubin is a promising mitochondrial activator and may represent a novel therapeutic strategy for age-related diseases.

TFE3-rearranged renal cell carcinoma (TFE3-RCC) is an aggressive kidney cancer driven by oncogenic TFE3 fusion transcription factors, yet the molecular machinery that enables these fusions to reprogram transcription and drive tumor growth remains poorly defined. Here, we identify the Cyclin C-CDK8/19 Mediator kinase module as an essential co-regulator of TFE3 fusion driven transcriptional programs and tumorigenesis. Inducible expression of PRCC-TFE3 in HK-2 cells, immortalized from normal renal epithelial cells, triggered a robust oncogene-induced senescence (OIS) phenotype. Using OIS as a functional readout, we performed a genome-wide CRISPR/Cas9 loss-of-function screen and identified CCNC, encoding Cyclin C, as an essential gene required for PRCC-TFE3 activity. Genetic disruption of CCNC or pharmacologic inhibition of CDK8/19 abrogated PRCC-TFE3 induced OIS, establishing the Mediator kinase module as a critical cofactor for PRCC-TFE3 dependent transcription. Mechanistically, PRCC-TFE3 promoted nuclear accumulation of Cyclin C and their co-occupancy at genomic regions bound and transcriptionally activated by PRCC-TFE3. RNA sequencing revealed that PRCC-TFE3 induced transcriptional programs, including lysosomal, TFEB-associated, and metabolic pathways, were broadly suppressed by CDK8/19 inhibition. Importantly, while PRCC-TFE3 and Cyclin C-CDK8/19 drive OIS in non-cancerous renal epithelial cells, this same transcriptional axis exerts a context dependent pro-tumorigenic function in TFE3-RCC. In xenografts established from patient derived TFE3-RCC cell lines, genetic deletion of CCNC suppressed tumor growth, whereas in an orthotopic syngeneic TFE3-RCC mouse model, pharmacologic CDK8/19 inhibition significantly reduced tumor progression. These findings define the Mediator kinase module as a mechanistic and therapeutic vulnerability in PRCC-TFE3 driven TFE3-RCC, providing a rationale for mechanism based targeted therapy.

The discovery of the senescence-associated secretory phenotype (SASP) has reshaped our understanding of cellular senescence, shifting its role from a solely tumor-suppressive mechanism to a potential driver of chronic inflammation and age-related diseases. Accordingly, senolytic drugs, which selectively eliminate senescent cells, have garnered considerable interest due to promising preclinical studies. However, concerns remain regarding the reproducibility and generalizability of these findings. In this cross-laboratory study, we rigorously tested the senolytic efficacy of a GLS1 inhibitor and an anti-PD-1 antibody—agents previously reported to reduce the burden of p16 INK4a -positive senescent cells and improve health outcomes in aged mice. Contrary to earlier reports, our study demonstrates that neither GLS1 inhibition nor PD-1 blockade significantly reduced p16 INK4a -positive cell burden or improved aging-related health parameters. Although we do not seek to discredit prior work, our results underscore the need for rigorous design, standardized protocols, and independent validation to ensure reliable senolytics before clinical translation.

Chronic inflammation is a key driver of aging-related diseases, obesity-associated metabolic disorders, and tumor progression. Aging and obesity contribute to the accumulation of senescent cells, which secrete senescence-associated secretory phenotype (SASP) factors that promote tissue remodeling and chronic inflammation. Here, we investigated the pathological roles of angiopoietin-like protein 2 (ANGPTL2), a potential SASP factor, in a mouse model of high-fat diet-induced premature aging. We found that ANGPTL2 deficiency shortened lifespan but attenuated systemic inflammation, indicating a complex role for ANGPTL2 in aging-related processes. ANGPTL2 was required for maintaining intestinal homeostasis under metabolic stress; however, ANGPTL2 also exacerbated adipocyte hypertrophy and cardiac dysfunction. Furthermore, ANGPTL2-mediated inflammation promoted kidney fibrosis but paradoxically protected against perivascular fibrosis in the liver, indicating its organ-specific effects on fibrotic remodeling. In addition, ANGPTL2 influenced immune responses by driving bronchus-associated lymphoid tissue formation. These findings suggest that ANGPTL2 has context-dependent effects, balancing tissue homeostasis and inflammation-driven pathologies. Our study provides novel insights into the dual roles of ANGPTL2 as a SASP factor in regulating inflammation, fibrosis, and tissue remodeling across different organ systems.

BACKGROUND:Angiopoietin-like protein 2 (ANGPTL2) is an aging-associated protein that contributes to the maintenance of tissue homeostasis. Excessive activation of ANGPTL2 disrupts this homeostatic process, leading to several adverse conditions, such as chronic inflammation, abnormal tissue remodeling, insulin resistance, and carcinogenesis. Nevertheless, only a very few studies have investigated the relationship between circulating ANGPTL2 concentrations and cause-specific mortality risk in the general population. METHODS:We conducted a prospective cohort study involving 2,912 community-dwelling Japanese adults aged ≥40 years with no prior history of cardiovascular diseases or cancer. Baseline serum ANGPTL2 concentrations (collected in 2002-2003) were quantified, and the participants were followed up for a median of 15.2 years. Hazards ratios (HRs) and 95% confidence intervals (CIs) for all-cause and cause-specific mortality were estimated using Cox proportional hazards models. RESULTS:During the follow-up period, 601 participants died (139 from cardiovascular diseases, 200 from cancer, 142 from infectious diseases, and 120 from other causes). Higher serum ANGPTL2 levels were significantly associated with increased risks of all-cause and cause-specific mortality (HR [95% CI] per 1-SD increment in log-transformed serum ANGPTL2 concentration: 1.34 [1.23-1.47] for all-cause mortality; 1.28 [1.06-1.55] for cardiovascular death; 1.31 [1.12-1.53] for cancer death; and 1.27 [1.05-1.54] for death from infectious diseases) after adjustment for potential confounders. These associations were modestly attenuated after additional adjustment for mediators related to insulin resistance and chronic inflammation. CONCLUSIONS:These findings indicate that elevated serum ANGPTL2 concentrations are associated with a higher risk of mortality from multiple causes.

Caloric restriction (CR) has shown the potential to extend lifespan and reduce cancer risk; however, the mechanisms underlying CR-mediated tumor suppression are not fully understood. Here, we investigate age-dependent CR effects on tumor progression and anti-tumor immune responses in a murine CR model. In aged mice, CR, defined as a 30% reduction in caloric intake, significantly suppressed tumor growth in murine syngeneic models of colorectal cancer or melanoma. CR also enhanced tumor infiltration by CD8+ T cells, which when depleted limited the tumor-suppressive effects of CR in aged mice. RNA-seq analysis of intratumoral CD8+ T cells revealed that CR upregulated the expression of genes associated with T cell function. Furthermore, mechanistic studies of effects of CR on age-related changes in CD8+ T cells, and immunohistochemical analysis suggested that normalization of the vasculature in the tumor microenvironment of aged CR mice is accompanied by decreased expression of angiogenic growth factors secreted by intratumoral CD8+ T cells. Our findings overall provide insight into age-dependent tumor-suppressive effects of CR and illustrate the essential role of CD8+ T cells in CR-mediated tumor suppression.

Age-related declines in cardiac function and exercise tolerance interfere with healthy living and decrease healthy life expectancy in older individuals. Tamogi-take mushrooms (Pleurotus cornucopiae) are known to contain high levels of Ergothioneine (EGT), an antioxidant with potential health benefits. In this study, we assessed the possibility that long-term consumption of Tamogi-take mushrooms might attenuate age-related decline in cardiac and vascular endothelial function in mice. We found that long-term intake of Tamogi-take mushrooms significantly maintained cardiac and vascular endothelial function and improved exercise tolerance in mice. Long-term mushroom consumption also increased levels of Nrf2 (Nuclear factor E2-related factor 2) protein in heart tissues and increased translation of HO-1 (Heme Oxygenase 1) proteins, which have antioxidant effects in heart and aortic tissues. Finally, long-term Tamogi-take mushroom consumption inhibited ROS accumulation with aging and reduced expression of inflammatory biomarkers. We conclude that ingestion of Tamogi-take mushrooms could serve as a dietary intervention to promote cardiovascular health, support healthy aging and slow the progression of age-related diseases.

Skin tissue, which consists of epidermal, dermal, and hypodermal cells, plays an important role in biological defense and physical appearance. External and internal stresses occurring with aging disrupt skin homeostasis, promoting the development of phenotypes associated with aging. Although many studies of skin aging focus on the dermis, potential epidermal changes have largely remained uncharacterized. In this study, we demonstrate that epidermal cells do not exhibit cellular senescence phenotypes with aging but instead show age-related decreases in mitochondrial number. We also found that mice lacking TFAM in epidermal cells exhibit delayed hair regrowth and impaired wound healing by middle age, resembling changes seen in skin of aged mice. Furthermore, middle-aged epidermis-specific TFAM-deficient mice exhibited obesity, suggesting that impaired fatty acid metabolism in epidermal cells resulting from mitochondrial decline may lead to obesity. These findings overall suggest that mitochondrial decline occurs as a primary event in epidermal aging and that antiaging strategies to enhance activity or number of epidermal mitochondria could antagonize both skin-aging phenotypes and age-related metabolic disease.

MiT/TFE gene fusions like SFPQ-TFE3 drive both epithelial (translocation RCC) and mesenchymal (PEComas) neoplasms. However, no mouse models for SFPQ-TFE3-related tumors exist and the underlying mechanisms of lineage plasticity remain unclear. Here, we demonstrate that constitutive murine renal expression of SFPQ-TFE3 disrupts kidney development with early neonatal renal failure and death, while post-natal induction induces infiltrative epithelioid tumors, that morphologically and transcriptionally resemble human PEComas, with strong activation of mTORC1 signaling via increased V-ATPase expression. Remarkably, SFPQ-TFE3 expression is sufficient to induce lineage plasticity, with down-regulation of the PAX2/PAX8 nephric lineage factors and tubular epithelial markers, and up-regulation of PEComa differentiation markers in transgenic mice, cell lines and human tRCC. mTOR inhibition downregulates SFPQ-TFE3 expression and rescues PAX8 expression and transcriptional activity in vitro. These data provide evidence of an epithelial cell-of-origin for TFE3-driven PEComas, highlighting a reciprocal role for SFPQ-TFE3 and mTOR in driving lineage plasticity in the kidney.

Tumor development often requires cellular adaptation to a unique, high metabolic state; however, the molecular mechanisms that drive such metabolic changes in TFE3-rearranged renal cell carcinoma (TFE3-RCC) remain poorly understood. TFE3-RCC, a rare subtype of RCC, is defined by the formation of chimeric proteins involving the transcription factor TFE3. In this study, we analyzed cell lines and genetically engineered mice, demonstrating that the expression of the chimeric protein PRCC-TFE3 induced a hypoxia-related signature by transcriptionally upregulating HIF1α and HIF2α. The upregulation of HIF1α by PRCC-TFE3 led to increased cellular ATP production by enhancing glycolysis, which also supplied substrates for the TCA cycle while maintaining mitochondrial oxidative phosphorylation. We crossed TFE3-RCC mouse models with Hif1α and/or Hif2α knockout mice and found that Hif1α, rather than Hif2α, is essential for tumor development in vivo. RNA-seq and metabolomic analyses of the kidney tissues from these mice revealed that ketone body production is inversely correlated with tumor development, whereas de novo lipid synthesis is upregulated through the HIF1α/SREBP1-dependent mechanism in TFE3-RCC. Our data suggest that the coordinated metabolic shift via the PRCC-TFE3/HIF1α/SREBP1 axis is a key mechanism by which PRCC-TFE3 enhances cancer cell metabolism, promoting tumor development in TFE3-RCC.

Dyslipidemia is a major risk factor for atherosclerosis and subsequent cardiovascular disease (CVD). Despite conventional treatment with statins, ezetimibe, or PCSK9 inhibitors, there are cases of familial hypercholesterolemia (FH) in which LDL-C levels cannot be sufficiently lowered to the target level, resulting in failure to prevent CVD. Inhibition of Angiopoietin-like protein 3 (ANGPTL3) has emerged as a new therapeutic strategy to reduce LDL-C levels independent of the LDL receptor function. Since ANGPTL3 suppresses lipoprotein lipase (LDL) and endothelial lipase (EL) activities, its inhibition facilitates the clearance of very low-density lipoprotein cholesterol, decreasing both LDL-C and triglyceride (TG) levels. In fact, evinacumab, an anti-ANGPTL3 monoclonal antibody, has been shown to substantially reduce LDL-C and TG levels, even in FH patients with LDL receptor gene mutations who are resistant to the conventional treatments described above. Clinical trials have also shown that siRNA therapeutics, such as zodasiran and solbinsiran, improve lipid profiles in patients with dyslipidemia. Recently, we have begun developing a peptide-based anti-ANGPTL3 vaccine and confirmed in a preclinical FH mouse model that it significantly decreases LDL-C and TG levels, reduces atherosclerotic lesions and maintains long-term efficacy without adverse effects. In this review, we discuss the promising advances in ANGPTL3-targeted therapeutics that may overcome treatment-resistant dyslipidemia and reduce CVD risk in high-risk populations.

INTRODUCTION:Tumor-induced host wasting marked by malnutrition, systemic inflammation, or altered body composition is associated with poor prognosis in cancer patients. Tumor cell-derived angiopoietin-like protein 2 (ANGPTL2) reportedly functions as a tumor promoter in some cancer contexts. This study aims to assess whether ANGPTL2 expression in tumor cells is associated with host wasting in patients with colorectal cancer. METHODS:We retrospectively enrolled 88 patients with all-stage colorectal cancer who underwent surgical resection of the primary tumor between January 2017 and December 2017 in a single institution. Based on immunohistochemistry staining, we assessed ANGPTL2 expression in tumor cells in paraffin-embedded tumor samples from resected specimens. The association of the ANGPTL2 expression with clinicopathological factors, biomarkers of host wasting, and survival were analyzed. RESULTS:Host wasting was associated with significantly high other causes-mortality rates in ANGPTL2-high patients (P = 0.0261) but not in ANGPTL2-low patients (P = 0.4719), suggesting that ANGPTL2 expression in colorectal cancer cells is associated with host wasting-related poor prognosis. Furthermore, ANGPTL2 expression in tumor cells was correlated with the advanced lung cancer inflammation index, which is a biomarker of host wasting (ρ = -0.3119, P = 0.0031). CONCLUSIONS:ANGPTL2 is associated with host wasting-related poor prognosis through its association with systemic inflammation in patients with colorectal cancer. These findings overall provide novel insight into ANGPTL2 function and illustrate the essential role of tumor-host interactions in the prognosis of cancer survivors.

OBJECTIVE:Cardiac function declines with age, impairing exercise tolerance and negatively impacting healthy aging. However, mechanisms driving age-related declines in cardiac function are not fully understood. METHODS:We examined mechanisms underlying age-related cardiac dysfunction using 3- and 24-month-old wild-type mice fed ad libitum or 24-month-old wild-type mice subjected to 70% calorie restriction (CR) starting at 2-month-old. In addition, cardiac aging phenotypes and mitochondrial biogenesis were also analyzed in 25-month-old cardiac-specific Hint1 knockout mice, 24-month-old CAG-Caren Tg mice, and 24-month-old wild-type mice injected with AAV6-Caren. RESULTS:We observed inactivation of mitochondrial biogenesis in hearts of aged mice. We also showed that activity of the BAF chromatin remodeling complex is repressed by HINT1, whose expression in heart increases with age, leading to decreased transcription of Tfam, which promotes mitochondrial biogenesis. Interestingly, CR not only suppressed age-related declines in cardiac function and mitochondrial biogenesis but blocked concomitant increases in cardiac HINT1 protein levels and maintained Tfam transcription. Furthermore, expression of the lncRNA Caren, which inhibits Hint1 mRNA translation, decreased with age in heart, and CR suppressed this effect. Finally, decreased HINT1 expression due to Caren overexpression antagonized age-related declines in mitochondrial biogenesis, ameliorating age-related cardiac dysfunction, exercise intolerance, and exercise-induced cardiac damage and subsequent death of mice. CONCLUSION:Our findings suggest that mitochondrial biogenesis in cardiomyocytes decreases with age and could underlie cardiac dysfunction, and that the Caren-HINT1-mitochondrial biogenesis axis may constitute a mechanism linking CR to resistance to cardiac aging. We also show that ameliorating declines in mitochondrial biogenesis in cardiomyocytes could counteract age-related declines in cardiac function, and that this strategy may improve exercise tolerance and extend so-called "healthy life span".

Caloric restriction (CR) without malnutrition reportedly improves life span and ameliorates aging in preclinical models. Decreased expressions of aging-related genes and inflammation-related genes have been observed in CR mice. Moreover, CR decreases cancer risk and inhibits tumor progression, but the underlying mechanisms are not fully understood. In this study, we developed a syngeneic model using C57BL/6N male mice, and verified the tumor-suppressing mechanisms of CR. Mice were randomized into 2 groups: normal diet (ND) group fed with ad lib diet, and CR group with 30% reduced feeding compared with the ND group, started from 2 months age. MC38, murine colorectal adenocarcinoma cells, were implanted subcutaneously. We compared tumor growth and survival between the CR group and the ND group. Moreover, to verify the contribution of tumor immunity, we compared the tumor-suppressing effects of anti-PD-1 antibody between the CR group and the ND group. To clarify the impacts of CD8+ cytotoxic T cells, we also conducted CD8 depletion by anti-CD8 antibody. Firstly, we observed significantly restricted tumor progression of the CR group in aged mice, but it was relatively modest in young mice. Secondly, the tumor-suppressing effect of anti-PD-1 was equivalent between the CR group and the ND group in aged mice, which suggests tumor immunity is essential to demonstrate anti-tumor effects in CR mice. However, CD8 depletion in CR mice showed only partial tumor-promoting effects, which suggests immune function excluding CD8+ T cells contributes to suppressing tumor progression in the CR group. Our findings suggest that CR ameliorates aging and tumor progression. Promoted immune function, especially immune cells excluding CD8+ T cells, might play a role in the tumor-suppressing effects of CR. CD4 depletion and comprehensive analyses of intratumoral T cells are currently underway to elucidate the underlying mechanisms of tumor suppression induced by CR. Taichi Horino, Haruki Horiguchi, Yuji Miyamoto, Masaaki Iwatsuki, Yuichi Oike. Caloric restriction ameliorates aging and tumor progression via tumor immunity in syngeneic mice model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 2554.