Bmi-1-RING1B prevents GATA4-dependent senescence-associated pathological cardiac hypertrophy by promoting autophagic degradation of GATA4

MiR-203 improves cardiac dysfunction by targeting PARP1-NAD+ axis in aging murine

Heart aging is a prevalent cause of cardiovascular diseases among the elderly. NAD+ depletion is a hallmark feature of aging heart, however, the molecular mechanisms that affect NAD+ depletion remain unclear. In this study, we identified microRNA-203 (miR-203) as a senescence-associated microRNA that regulates NAD+ homeostasis. We found that the blood miR-203 level negatively correlated with human age and its expression significantly decreased in the hearts of aged mice and senescent cardiomyocytes. Transgenic mice with overexpressed miR-203 (TgN (miR-203)) showed resistance to aging-induced cardiac diastolic dysfunction, cardiac remodeling, and myocardial senescence. At the cellular level, overexpression of miR-203 significantly prevented D-gal-induced cardiomyocyte senescence and mitochondrial damage, while miR-203 knockdown aggravated these effects. Mechanistically, miR-203 inhibited PARP1 expression by targeting its 3'UTR, which helped to reduce NAD+ depletion and improve mitochondrial function and cell senescence. Overall, our study first identified miR-203 as a genetic tool for anti-heart aging by restoring NAD+ function in cardiomyocytes.

Synaptotagmin-7 mediates cardiac hypertrophy by targeting autophagy

Sustained cardiac hypertrophy damages the heart and weakens cardiac function, often leading to heart failure and even death. Pathological cardiac hypertrophy has become a central therapeutic target for many heart diseases including heart failure. However, the underlying mechanisms of cardiac hypertrophy, especially the involvement of autophagy program, are still ill-understood. Synaptotagmin-7 (Syt7), a multifunctional and high-affinity calcium sensor, plays a pivotal role in asynchronous neurotransmitter release, synaptic facilitation, and vesicle pool regulation during synaptic transmission. However, little is known about whether Syt7 is expressed in the myocardium and involved in the pathogenesis of heart diseases. Here we showed that Syt7 was significantly upregulated in Ang II-treated hearts and cardiomyocytes. Homozygous syt7 knockout (syt7-/-) mice exhibited significantly attenuated cardiac hypertrophy and fibrosis and improved cardiac function. We further found that Syt7 exerted a pro-hypertrophic effect by suppressing the autophagy process. In exploring the upstream mechanisms, microRNA (miR)-93 was identified to participate in the regulation of Syt7 expression. miR-93 protected hearts against Ang II-induced hypertrophy through targeting Syt7-autophagy pathway. In summary, our data reveal a new cardiac hypertrophy regulator and a novel hypertrophy regulating model composed of miR-93, Syt7 and autophagy program. These molecules may serve as potential therapeutic targets in the treatment of cardiac hypertrophy and heart failure.

The transcription factor GATA6 accelerates vascular smooth muscle cell senescence-related arterial calcification by counteracting the role of anti-aging factor SIRT6 and impeding DNA damage repair

Arterial calcification is a hallmark of vascular pathology in the elderly and in individuals with chronic kidney disease (CKD). Vascular smooth muscle cells (VSMCs), after attaining a senescent phenotype, are implicated in the calcifying process. However, the underlying mechanism remains to be elucidated. Here, we reveal an aberrant upregulation of transcriptional factor GATA6 in the calcified aortas of humans, mice with CKD and mice subjected to vitamin D3 injection. Knockdown of GATA6, via recombinant adeno-associated virus carrying GATA6 shRNA, inhibited the development of arterial calcification in mice with CKD. Further gain- and loss-of function experiments in vitro verified the contribution of GATA6 in osteogenic differentiation of VSMCs. Samples of human aorta exhibited a positive relationship between age and GATA6 expression and GATA6 was also elevated in the aortas of old as compared to young mice. Calcified aortas displayed senescent features with VSMCs undergoing premature senescence, blunted by GATA6 downregulation. Notably, abnormal induction of GATA6 in senescent and calcified aortas was rescued in Sirtuin 6 (SIRT6)-transgenic mice, a well-established longevity mouse model. Suppression of GATA6 accounted for the favorable effect of SIRT6 on VSMCs senescence prevention. Mechanistically, SIRT6 inhibited the transcription of GATA6 by deacetylation and increased degradation of transcription factor Nkx2.5. Moreover, GATA6 was induced by DNA damage stress during arterial calcification and subsequently impeded the Ataxia-telangiectasia mutated (ATM)-mediated DNA damage repair process, leading to accelerated VSMCs senescence and osteogenic differentiation. Thus, GATA6 is a novel regulator in VSMCs senescence. Our findings provide novel insight in arterial calcification and a potential new target for intervention.

Upregulation of Hsp27 via further inhibition of histone H2A ubiquitination confers protection against myocardial ischemia/reperfusion injury by promoting glycolysis and enhancing mitochondrial function

Research suggests that ischemic glycolysis improves myocardial tolerance to anoxia and low-flow ischemia. The rate of glycolysis during ischemia reflects the severity of the injury caused by ischemia and subsequent functional recovery following reperfusion. Histone H2AK119 ubiquitination (H2Aub) is a common modification that is primarily associated with gene silencing. Recent studies have demonstrated that H2Aub contributes to the development of cardiovascular diseases. However, the underlying mechanism remains unclear. This study identified Hsp27 (heat shock protein 27) as a H2Aub binding protein and explored its involvement in mediating glycolysis and mitochondrial function. Functional studies revealed that inhibition of PRC1 (polycomb repressive complex 1) decreased H2Aub occupancy and promoted Hsp27 expression through inhibiting ubiquitination. Additionally, it increased glycolysis by activating the NF-κB/PFKFB3 signaling pathway during myocardial ischemia. Furthermore, Hsp27 reduced mitochondrial ROS production by chaperoning COQ9, and suppressed ferroptosis during reperfusion. A delivery system was developed based on PCL-PEG-MAL (PPM)-PCM-SH (CWLSEAGPVVTVRALRGTGSW) to deliver PRT4165 (PRT), a potent inhibitor of PRC1, to damaged myocardium, resulting in decreased H2Aub. These findings revealed a novel epigenetic mechanism connecting glycolysis and ferroptosis in protecting the myocardium against ischemia/reperfusion injury.

Finding New Targets for the Treatment of Heart Failure: Endoplasmic Reticulum Stress and Autophagy

Heart failure is a progressive disease with an annual mortality rate of about 10% and is the end-stage stage of various heart diseases, which places a huge socioeconomic burden on the healthcare system. The development of heart failure has received increasing attention as a potential way to improve the treatment of this disease. Many studies have shown that endoplasmic reticulum stress and autophagy play an important role in the occurrence and development of heart failure. With the in-depth study of endoplasmic reticulum stress and autophagy, both are considered promising targets for pharmacological interventions to treat heart failure, but the mechanism of heart failure between the two is not clear. This review will highlight the effects of endoplasmic reticulum stress, autophagy, and their interactions in the development and development of heart failure, thereby helping to provide direction for the future development of targeted therapies for patients with heart failure. CLINICAL RELEVANCE: This study explored the new targets for the treatment of heart failure: endoplasmic reticulum stress and autophagy. Targeted drug therapy for endoplasmic reticulum stress and autophagy is expected to provide a new intervention target for the treatment of heart failure.

RNF13 protects against pathological cardiac hypertrophy through p62-NRF2 pathway

Heart failure (HF) severely impairs human health because of its high incidence and mortality. Cardiac hypertrophy is the main cause of HF, while its underlying mechanism is not fully clear. As an E3 ubiquitin ligase, Ring finger protein 13 (RNF13) plays a crucial role in many disorders, such as liver immune, neurological disease and tumorigenesis, whereas the function of RNF13 in cardiac hypertrophy remains largely unknown. In the present study, we found that the protein expression of RNF13 is up-regulated in the transverse aortic constriction (TAC)-induced murine hypertrophic hearts and phenylephrine (PE)-induced cardiomyocyte hypertrophy. Functional investigations indicated that RNF13 global knockout mice accelerates the degree of TAC-induced cardiac hypertrophy, including cardiomyocyte enlargement, cardiac fibrosis and heart dysfunction. On the contrary, adeno-associated virus 9 (AAV9) mediated-RNF13 overexpression mice alleviated cardiac hypertrophy. Furthermore, we demonstrated that adenoviral RNF13 attenuates the PE-induced cardiomyocyte hypertrophy and down-regulates the expression of cardiac hypertrophic markers, while the opposite results were observed in the RNF13 knockdown group. The RNA-sequence of RNF13 knockout and wild type mice showed that RNF13 deficiency activates oxidative stress after TAC surgery. In terms of the mechanism, we found that RNF13 directly interacted with p62 and promoted the activation of downstream NRF2/HO-1 signaling. Finally, we proved that p62 knockdown can reverse the effect of RNF13 in cardiac hypertrophy. In conclusion, RNF13 protects against the cardiac hypertrophy via p62-NRF2 axis.

Bmi-1 Overexpression Improves Sarcopenia Induced by 1,25(OH)2 D3 Deficiency and Downregulates GATA4-Dependent Rela Transcription

Sarcopenia increases with age, and an underlying mechanism needs to be determined to help with designing more effective treatments. This study aimed to determine whether 1,25(OH)₂ D₃ deficiency could cause cellular senescence and a senescence-associated secretory phenotype (SASP) in skeletal muscle cells to induce sarcopenia, whether GATA4 could be upregulated by 1,25(OH)₂ D₃ deficiency to promote SASP, and whether Bmi-1 reduces the expression of GATA4 and GATA4-dependent SASP induced by 1,25(OH)₂ D₃ deficiency in skeletal muscle cells. Bioinformatics analyses with RNA sequencing data in skeletal muscle from physiologically aged and young mice were conducted. Skeletal muscles from 2-month-old young and 2-year-old physiologically aged wild-type (WT) mice and 8-week-old WT, Bmi-1 mesenchymal transgene (Bmi-1^Tg ), Cyp27b1 homozygous (Cyp27b1^-/- ), and Bmi-1^Tg Cyp27b1^-/- mice were observed for grip strength, cell senescence, DNA damage, and NF-κB-mediated SASP signaling of skeletal muscle. We found that muscle-derived Bmi-1 and vitamin D receptor (VDR) decreased with physiological aging, and DNA damage and GATA4-dependent SASP activation led to sarcopenia. Furthermore, 1,25(OH)₂ D₃ deficiency promoted DNA damage-induced GATA4 accumulation in muscles. GATA4 upregulated Rela at the region from -1448 to -1412 bp at the transcriptional level to cause NF-κB-dependent SASP for aggravating cell senescence and muscular dysfunction and sarcopenia. Bmi-1 overexpression promoted the ubiquitination and degradation of GATA4 by binding RING1B, which prevented cell senescence, SASP, and dysfunctional muscle, and improved sarcopenia induced by 1,25(OH)₂ D₃ deficiency. Thus, Bmi-1 overexpression improves sarcopenia induced by 1,25(OH)₂ D₃ deficiency, downregulates GATA4-dependent Rela transcription, and sequentially inhibits GATA4-dependent SASP in muscle cells. Therefore, Bmi-1 overexpression could be used for translational gene therapy for the ubiquitination of GATA4 and prevention of sarcopenia. © 2023 American Society for Bone and Mineral Research (ASBMR).

Molecular mechanisms of sacubitril/valsartan in cardiac remodeling

Cardiovascular diseases have become a major clinical burden globally. Heart failure is one of the diseases that commonly emanates from progressive uncontrolled hypertension. This gives rise to the need for a new treatment for the disease. Sacubitril/valsartan is a new drug combination that has been approved for patients with heart failure. This review aims to detail the mechanism of action for sacubitril/valsartan in cardiac remodeling, a cellular and molecular process that occurs during the development of heart failure. Accumulating evidence has unveiled the cardioprotective effects of sacubitril/valsartan on cellular and molecular modulation in cardiac remodeling, with recent large-scale randomized clinical trials confirming its supremacy over other traditional heart failure treatments. However, its molecular mechanism of action in cardiac remodeling remains obscure. Therefore, comprehending the molecular mechanism of action of sacubitril/valsartan could help future research to study the drug’s potential therapy to reduce the severity of heart failure.

Sirt1 overexpression improves senescence-associated pulmonary fibrosis induced by vitamin D deficiency through downregulating IL-11 transcription

Determining the mechanism of senescence-associated pulmonary fibrosis is crucial for designing more effective treatments for chronic lung diseases. This study aimed to determine the following: whether Sirt1 and serum vitamin D decreased with physiological aging, promoting senescence-associated pulmonary fibrosis by activating TGF-β1/IL-11/MEK/ERK signaling, whether Sirt1 overexpression prevented TGF-β1/IL-11/MEK/ERK signaling-mediated senescence-associated pulmonary fibrosis in vitamin D-deficient (Cyp27b1^-/- ) mice, and whether Sirt1 downregulated IL-11 expression transcribed by TGF-β1/Smad2 signaling through deacetylating histone at the IL-11 promoter in pulmonary fibroblasts. Bioinformatics analysis with RNA sequencing data from pulmonary fibroblasts of physiologically aged mice was conducted for correlation analysis. Lungs from young and physiologically aged wild-type (WT) mice were examined for cell senescence, fibrosis markers, and TGF-β1/IL-11/MEK/ERK signaling proteins, and 1,25(OH)₂ D₃ and IL-11 levels were detected in serum. Nine-week-old WT, Sirt1 mesenchymal transgene (Sirt1^Tg ), Cyp27b1^-/- , and Sirt1^Tg Cyp27b1^-/- mice were observed the pulmonary function, aging, and senescence-associated secretory phenotype and TGF-β1/IL-11/MEK/ERK signaling. We found that pulmonary Sirt1 and serum vitamin D decreased with physiological aging, activating TGF-β1/IL-11/MEK/ERK signaling, and promoting senescence-associated pulmonary fibrosis. Sirt1 overexpression improved pulmonary dysfunction, aging, DNA damage, senescence-associated secretory phenotype, and fibrosis through downregulating TGF-β1/IL-11/MEK/ERK signaling in Cyp27b1^-/- mice. Sirt1 negatively regulated IL-11 expression through deacetylating H3K9/14ac mainly at the region from -871 to -724 of IL-11 promoter, also the major binding region of Smad2 which regulated IL-11 expression at the transcriptional level, and subsequently inhibiting TGF-β1/IL-11/MEK/ERK signaling in pulmonary fibroblasts. This signaling in aging fibroblasts could be a therapeutic target for preventing senescence-associated pulmonary fibrosis induced by vitamin D deficiency.