GDF-11

GDF11 protects against sepsis-induced myocardial injury and cardiac dysfunction by targeting the Nrf2 signaling pathway-dependent ferroptosis.

Haibo Zhang, Yutian Mi, Chunling Kong +4 more

Sepsis, a systemic inflammatory response syndrome caused by infection, can lead to life-threatening multi-organ dysfunction. Among its complications, sepsis-induced cardiomyopathy (SIC) represents one of the most severe conditions with poor prognosis. Currently, pharmacological options for clinical management of SIC are limited and often yield suboptimal outcomes, necessitating the urgent exploration of novel therapeutic strategies. Growth differentiation factor 11 (GDF11), a member of the transforming growth factor-β (TGF-β) superfamily, possesses a variety of biological properties. Importantly, recent studies have highlighted the crucial protective role of GDF11 in various cardiovascular diseases. However, to date, there have been no reports on the alterations and effects of GDF11 in SIC. In this study, we initially observed a significant downregulation of GDF11 expression in both myocardium and serum of C57BL/6 J mice treated with lipopolysaccharide (LPS). Subsequently, through endogenous overexpression of GDF11 or exogenous supplementation with recombinant GDF11, we found that GDF11 mitigated lipid peroxidation-dependent ferroptosis by inhibiting iron accumulation and ameliorating mitochondrial dysfunction, thereby alleviating cardiac dysfunction and myocardial injury in septic mice. Additionally, our cellular experiments demonstrated that GDF11 could also inhibit LPS-induced ferroptosis in neonatal mouse cardiomyocytes. Nevertheless, blocking the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway using ML385 in vivo or Nrf2 siRNA in vitro abrogated the above protective effects of GDF11 against SIC. Taken together, our findings show that GDF11 may alleviate SIC by inhibiting cardiomyocyte ferroptosis through activation of the Nrf2 signaling pathway, suggesting GDF11 as a potential therapeutic target for treating patients with sepsis.

Growth differentiation factor 11 attenuates doxorubicin-induced cardiotoxicity by inhibiting myocardial pyroptosis and oxidative stress.

Jiangping Ye, Yehong Liu, Feng Xu +8 more

Doxorubicin (DOX) is limited in clinical application because of its cardiotoxicity. One of the key elements of DOX-induced cardiotoxicity is pyroptosis, a kind of programmed cell death brought on by immunity and followed by inflammatory response. Growth differentiation factor (GDF) 11 plays an significant role in oxidative stress and inflammation. The purpose of this work was to determine if GDF11 inhibits oxidative stress and pyroptosis in order to lessen the cardiotoxicity caused by DOX. SD rats were used to establish an in vivo model by intraperitoneal injection of DOX and induction of GDF11 overexpression in the heart using adeno-associated virus type 9 (AAV9). Human cardiomyocytes (AC16) were used to create the in-vitro model. By measuring the degree of cardiac function, cardiac fibrosis, inflammation, and oxidative stress; using transmission electron microscopy to examine the rat heart's microstructure; analyzing the expression of proteins of pyroptosis and oxidative stress-associated nuclear factor E2-related factor (Nrf-2)/heme oxygenase-1 (HO-1) pathway, the protective mechanism of GDF11 against DOX-induced cardiotoxicity was explored. GDF11 decreased the expression level of cardiac function, oxidative stress and inflammation-related indexes, attenuated the degree of DOX-induced cardiac fibrosis, and had some protective effects against damage to the rat heart's microstructures. Besides, GDF11 decreased the level of oxidative stress and restored the levels of anti-oxidative stress and other proteins, including Nrf-2, while also reduced the expression of DOX-induced pyroptosis-related proteins. GDF11 attenuates DOX-induced cardiotoxicity by inhibiting pyroptosis and oxidative stress, which provides new ideas for clinical improvement of DOX-induced myocardial injury.

Transcription Factor SP1 Drives Myocardial Ischemia/reperfusion Injury By Transcription Activation-mediated GADD45G Upregulation.

Yaping Wang, Jianying Xue, Mingliang Cui +2 more

Myocardial ischemia-reperfusion injury (MIRI) is an unresolved clinically fatal complication in the management of acute myocardial infarction (AMI). Growth arrest and DNA damage-inducible gene 45 Gamma (GADD45G) plays a vital role in the regulation of MIRI. However, the underlying mechanisms remain unclear. GADD45G and SP1 expression were upregulated in hypoxia/reoxygenation (H/R)-treated H9C2 cells. H/R treatment repressed H9C2 cell viability, and induced apoptosis, oxidative stress, and inflammatory response. Moreover, GADD45G deficiency could relieve H/R-triggered H9C2 cell injury. In mechanism, SP1 was a transcription factor of GADD45G and activated the transcription of GADD45G via binding to its promoter region. Besides, SP1 knockdown alleviated MI/R-induced pathological damage in the myocardial tissue of rats by regulating GADD45G. In conclusion, SP1 could promote H/R-induced cardiomyocyte injury and MI/R-caused rat myocardial tissue pathological injury by increasing GADD45G, providing a promising therapeutic target for MIRI treatment.

Sinomenine hydrochloride alleviates autoimmune myocarditis via suppressing Th1 cell induced-M1 macrophage pyroptosis.

Zhenhao Zhang, Yulong Xiong, Shangyu Liu +11 more

CD4+ T cells are crucial to the cardiac autoimmunity of myocarditis, with the underlying pathogenesis remaining unclear. Sinomenine hydrochloride, a natural compound from Sinomenium acutum, is reported to protect against some autoimmune diseases. This study aimed to elucidate the role of CD4+ T-helper 1 (Th1) cells in regulating inflammatory cell death and investigate the effect of sinomenine hydrochloride on Th1 cells and myocarditis.

Uridine-Cytidine Kinase 2 (UCK2)/Uridine-Cytidine Kinase Like 1 (UCKL1) complex exacerbates the differentiation of myocardial fibroblasts via TRIM21/Smurf2/Smad3 pathway after myocardial infarction.

Xiao Zhou, Yu Zhang, Hao Wang +5 more

Cardiac fibrosis following myocardial infarction (MI) is a pivotal driver of ventricular dysfunction and heart failure, yet the molecular checkpoints orchestrating the persistent activation of cardiac fibroblasts remain incompletely defined. Here, we uncover a non-canonical, metabolism-independent function of Uridine-Cytidine Kinase 2 (UCK2) and Uridine-Cytidine Kinase Like-1 (UCKL1) as synergistic regulators of pathological remodeling. We demonstrate that both proteins are robustly upregulated in the border zone of ischemic murine hearts and transforming growth factor-β (TGF-β)-activated human cardiac fibroblasts (HCFs). Mechanistically, UCK2 and UCKL1 physically assemble into an obligate functional complex that acts as a molecular scaffold rather than a metabolic enzyme. This complex recruits the E3 ubiquitin ligase Tripartite Motif Containing 21 (TRIM21) to orchestrate the specific ubiquitination and degradation of the negative regulator SMAD Specific E3 Ubiquitin Protein Ligase 2 (Smurf2), thereby sustaining SMAD Family Member 3 (Smad3) phosphorylation and amplifying fibrogenic TGF-β signaling. Disruption of this axis via combined genetic silencing exerts a synergistic protective effect by abrogating myofibroblast differentiation and extracellular matrix production. Furthermore, therapeutic intervention using adeno-associated virus (AAV)-mediated knockdown of UCK2/UCKL1 significantly attenuates adverse ventricular remodeling, limits scar expansion, and preserves cardiac function in a murine MI model. Collectively, these findings identify the UCK2/UCKL1-TRIM21-Smurf2-Smad3 axis as a novel, druggable signalosome linking kinase "moonlighting" functions to transcriptional reprogramming, offering a transformative therapeutic strategy to arrest the progression of post-ischemic heart failure.

PFKFB3 Promotes Myofibroblast Differentiation and Cardiac Fibrosis Through its Intra- and Extra- Cellular Roles.

Bing Han, Zhaowei Zhu, Yongxiang Wang +4 more

Cardiac fibrosis remains a major clinical challenge with limited therapeutic options, and the role of PFKFB3 in its pathogenesis remains unclear. Single-cell RNA sequencing analysis was applied and the results demonstrated that glycolysis was most prominently enhanced in activated cardiac myofibroblasts (myoCFs) in cardiomyopathy. Western blot analysis revealed that PFKFB3 expression was significantly increased in fibrotic hearts and TGF-β1-stimulated myoCFs. Genetic (Pfkfb3+/-) and pharmacological (3PO) inhibition of PFKFB3 attenuated myoCF activation, proliferation, and migration, while also reducing cardiac fibrosis in isoproterenol- and coronary ligation- induced mouse models. Mechanistically, TGF-β1 upregulated PFKFB3 in a HIF-1α-dependent manner, and extracellular PFKFB3 further promoted fibroblast activation and inflammatory responses. Clinically, elevated plasma PFKFB3 levels, as measured by ELISA, were significantly associated with fibrosis severity in patients with cardiomyopathy. These findings reveal for the first time that PFKFB3 drives cardiac fibrosis dually through intracellular glycolytic regulation and extracellular signaling, highlighting its translational potential.

GDF11 Alleviates Vascular Calcification in VitD3-Overloaded Mice Through Inhibition of Inflammatory NF-κB Signal.

Jiali Huang, Qingchun Liang, Yuanzhi Ye +4 more

Vascular calcification, an age-associated disorder, is a highly regulated biological process similar to bone formation. Growth differentiation factor 11 (GDF11), a secreted member of the transforming growth factor beta (TGF-β) superfamily, has been shown to act as an anti-aging factor in the brain, heart, skin, and skeletal muscle. Nevertheless, whether GDF11 affects vascular calcification and the underlying mechanisms remain unclear. In the present study, beta-glycerophosphate and calcium chloride-induced calcification of vascular smooth muscle cells (VSMCs) and a VitD3-overloaded mouse model were used to investigate the role of GDF11 in vascular calcification. Our results revealed that the knockdown of GDF11 by siRNA promoted the calcification of rat VSMCs, whereas GDF11 treatment significantly reduced the calcification of human and rat VSMCs in vitro, as detected by alizarin red staining and calcium content assay. Similarly, GDF11 treatment reduced the expression of bone-related molecules including Runt-related transcription factor 2 (Runx2) and bone morphogenetic protein-2 (BMP2). Furthermore, ex vivo and in vivo studies confirmed the inhibitory effect of GDF11 on vascular calcification. Mechanistically, GDF11 treatment reduced the levels of NF-κB signaling molecules including NLRP3, phosphorylated p65, IL-6, and IL-1β in VSMCs. Additionally, GDF11 siRNA-induced VSMC calcification was repressed by NF-κB inhibitor PDTC treatment. Taken together, these findings suggest that GDF11 alleviates vascular calcification through inhibiting the NF-κB signal. Modulation of GDF11 may represent a therapeutic strategy for vascular calcification.

GDF11 alleviates cardiac ischemia/reperfusion injury by suppressing the mtDNA damage-inflammatory response axis.

Dan Zhao, Zihui Wang, Yanyan Chen +8 more

Growth differentiation factor 11 (GDF11) has been reported to play a protective role in myocardial infarction. Mitochondrial DNA (mtDNA) damage is one of the pivotal factors in the initiation of myocardial cell damage. However, whether GDF11 can ameliorate mtDNA damage through its cardioprotective effect remains largely unknown. In this study, we obtained the GDF11-Fc fusion protein from mammalian cells and evaluated its cardioprotective effect in a mouse myocardial infarction model by TTC-Evans blue staining and morphological and enzymatic detection. Similar protective effects were observed in H9C2 cells and NRVMs. Mechanistically, we found that mtDNA damage was increased in I/R hearts. Exogenous administration of GDF11-Fc alleviated mtDNA damage and subsequent NLRP3 inflammasome activity, possibly through a reduction in ROS. In conclusion, GDF11 can ameliorate myocardial ischemia-reperfusion injury by inhibiting the inflammatory response induced by mtDNA damage.

[Astragaloside IV regulates Snail1 lactylation and acetylation to mediate macrophage polarization and improve myocardial infarction].

Shaopeng Chen, Rudian Kang, Xinbao Hong +1 more

Objective To investigate the impact of Astragaloside-IV (AS-IV) on the progression of myocardial infarction (MI) through macrophage-dependent mechanisms by regulating Snail1 lactylation and acetylation, as well as the transforming growth factor β (TGF-β) pathway. Methods Oxygen glucose deprivation (OGD) was used to establish an in vitro myocardial ischemia model in rat cardiomyocytes (H9c2), which were then treated with AS-IV. Cell viability was assessed using CCK-8, apoptosis was evaluated by flow cytometry, and LDH levels were measured to assess cellular damage. RAW246.7 cells were treated with LPS, and lactate levels in the supernatant were measured using ELISA, while expression of macrophage phenotype markers was evaluated using Western blot. RAW246.7 cell-conditioned medium (CM) was co-cultured with H9c2 cells to assess the protective effects of AS-IV on macrophage CM-mediated H9c2 damage. RAW246.7 cells were induced to differentiate into M1-like macrophages using LPS (100 ng/mL) + IFN-γ (20 ng/mL), and Snail1 was overexpressed in M1 macrophages. Transfected M1 macrophage CM was co-cultured with H9c2 cells to validate the mechanisms of AS-IV in MI. An MI rat model was established by ligation of the left anterior descending coronary artery (LAD), and was treated with AS-IV. Cardiac function, myocardial cell apoptosis, and cardiac tissue pathology were studied using echocardiography, TUNEL, and HE staining, respectively. Results Compared to the OGD group, AS-IV treatment promoted cell viability, reduced apoptosis and decreased LDH release. LPS upregulated lactate levels in the supernatant of RAW246.7 cell cultures and induced polarization of RAW246.7 cells to the M1 phenotype. AS-IV attenuated the damaging effects of RAW246.7 cell CM on H9c2 cells . Overexpression of Snail1 in M1 macrophages weakened the protective effects of AS-IV on H9c2 cells . In vivo study, results showed that, compared to the MI group, AS-IV treatment reduced lactate levels in the hearts of MI rats, improved cardiac function and myocardial injury and attenuated myocardial cell apoptosis. Conclusion AS-IV inhibits TGF-β pathway activation through the suppression of Snail1 lactylation and acetylation in a macrophage-dependent manner, thereby mitigating myocardial cell damage following MI.

Sevoflurane Activates PI3K/AKT Signaling Pathway by Upregulating GDF11 Expression to Attenuate Ischemia/Reperfusion Injury in Cardiomyocytes.

Rong-Sheng Zhou, Xiao-Hong Xue, Yang Bi +4 more

Myocardial ischemia/reperfusion (I/R) injury stands as a primary contributor to ischemic heart disease. Sevoflurane (SEVO), a commonly used inhalation anesthetic, has been shown to exert a direct protective effect on ischemic heart injury. However, the specific mechanism by which it exerts the protective effect remains unclear. This study was designed to investigate the role of SEVO in myocardial I/R injury and its potential molecular mechanisms.

Growth differentiation factor 11 alleviates oxidative stress-induced senescence of endothelial progenitor cells via activating autophagy.

Ping Tao, Hai-Feng Zhang, Pei Zhou +3 more

Stem cell transplantation has been regarded as a promising therapeutic strategy for myocardial regeneration after myocardial infarction (MI). However, the survival and differentiation of the transplanted stem cells in the hostile ischaemic and inflammatory microenvironment are poor. Recent studies have focused on enhancing the survival and differentiation of the stem cells, while strategies to suppress the senescence of the transplanted stem cells is unknown. Therefore, we investigated the effect of growth differentiation factor 11 (GDF11) on attenuating oxidative stress-induced senescence in the engrafted endothelial progenitor cells (EPCs).

GDF15 attenuates sepsis-induced myocardial dysfunction by inhibiting cardiomyocytes ferroptosis via the SOCS1/GPX4 signaling pathway.

Xiayun Li, He Sun, Liyun Zhang +10 more

Sepsis is a systemic inflammatory response syndrome triggered by infection, presenting with symptoms such as fever, increased heart rate, and low blood pressure. In severe cases, it can lead to multiple organ dysfunction, posing a life-threatening risk. Sepsis-induced cardiomyopathy (SIC) is a critical factor in the poor prognosis of septic patients, leading to myocardial dysfunction characterized by cell death, inflammation, and diminished cardiac function. Ferroptosis, an iron-dependent form of programmed cell death, is a key mechanism causing cardiomyocyte damage in SIC. Growth differentiation factor 15 (GDF15), a member of the TGF-β superfamily, is associated with various cardiovascular diseases and can inhibit oxidative stress, reduce reactive oxygen species (ROS), and suppress ferroptosis. Elevated serum GDF15 levels in sepsis are correlated with organ injuries, suggesting its potential as a therapeutic target. However, its role and mechanisms in SIC remain unclear. Glutathione peroxidase 4 (GPX4), the only enzyme capable of reducing lipid peroxides within cells, protects cells by reducing lipid peroxidation levels and inhibiting ferroptosis. Investigating the regulatory factors of GPX4 may provide a theoretical basis for SIC treatment. In this study, a mouse SIC model revealed that elevated GDF15 exerts a protective effect. Antagonizing GDF15 exacerbates myocardial damage. Through transcriptomic analysis and other methods, we confirmed that GDF15 inhibits the expression of SOCS1 by activating the ALK5-SMAD2/3 pathway, thereby activates the JAK2/STAT3 pathway, promotes the transcription of GPX4, inhibits ferroptosis in cardiomyocytes, and plays a myocardial protective role in SIC.

Growth differentiation factor 11 regulates high glucose-induced cardiomyocyte pyroptosis and diabetic cardiomyopathy by inhibiting inflammasome activation.

Jing Zhang, Guolong Wang, Yuxuan Shi +7 more

Diabetic cardiomyopathy (DCM) is a crucial complication of long-term chronic diabetes that can lead to myocardial hypertrophy, myocardial fibrosis, and heart failure. There is increasing evidence that DCM is associated with pyroptosis, a form of inflammation-related programmed cell death. Growth differentiation factor 11 (GDF11) is a member of the transforming growth factor β superfamily, which regulates oxidative stress, inflammation, and cell survival to mitigate myocardial hypertrophy, myocardial infarction, and vascular injury. However, the role of GDF11 in regulating pyroptosis in DCM remains to be elucidated. This research aims to investigate the role of GDF11 in regulating pyroptosis in DCM and the related mechanism.

Differential Expression and Bioinformatics Analysis of CircRNA in PDGF-BB-Induced Vascular Smooth Muscle Cells.

Jiangtian Tian, Yahong Fu, Qi Li +7 more

Atherosclerosis is mediated by various factors and plays an important pathological foundation for cardiovascular and cerebrovascular diseases. Abnormal vascular smooth muscle cells (VSMCs) proliferation and migration have an essential role in atherosclerotic lesion formation. Circular RNAs (circRNA) have been widely detected in different species and are closely related to various diseases. However, the expression profiles and molecular regulatory mechanisms of circRNAs in VSMCs are still unknown. We used high-throughput RNA-seq as well as bioinformatics tools to systematically analyze circRNA expression profiles in samples from different VSMC phenotypes. Polymerase chain reaction (PCR), Sanger sequencing, and qRT-PCR were performed for circRNA validation. A total of 22191 circRNAs corresponding to 6273 genes (host genes) in the platelet-derived growth factor (PDGF-BB) treated group, the blank control group or both groups, were detected, and 112 differentially expressed circRNAs were identified between the PDGF-BB treated and control groups, of which 59 were upregulated, and 53 were downregulated. We selected 9 circRNAs for evaluation of specific head-to-tail splicing, and 10 differentially expressed circRNAs between the two groups for qRT-PCR validation. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses enrichment analyses revealed that the parental genes of the circRNAs mainly participated in cardiac myofibril assembly and positive regulation of DNA-templated transcription, indicating that they might be involved in cardiovascular diseases. Finally, we constructed a circRNA-miRNA network based on the dysregulated circRNAs and VSMC-related microRNAs. Our study is the first to show the differential expression of circRNAs in PDGF-BB-induced VSMCs and may provide new ideas and targets for the prevention and therapy of vascular diseases.

GDF11 mitigates high glucose-induced cardiomyocytes apoptosis by inhibiting the ALKBH5-FOXO3-CDR1as/Hippo signaling pathway.

Yingchun Shao, Mengmeng Li, Yanying Wang +17 more

Diabetic cardiomyopathy remains a formidable health challenge with a high mortality rate and no targeted treatments. Growth differentiation factor 11 (GDF11) has shown promising effects on cardiovascular diseases; however, its role and the underlying mechanism in regulating diabetic cardiomyopathy remain unclear. In this study, we developed mouse models of diabetic cardiomyopathy using leptin receptor-deficient (db/db) mice and streptozocin-induced C57BL/6 mice. The diabetic cardiomyopathy model mice exhibited apparent structural damage in cardiac tissues and a significant increase in the expression of apoptosis-related proteins. Notably, we observed a significant decreased expression of GDF11 in the myocardium of mice with diabetic cardiomyopathy. Moreover, GDF11 cardiac-specific knock-in mice (transgenic mice) exhibited improved cardiac function and reduced apoptosis. Moreover, exogenous administration of GDF11 mitigated high glucose-induced cardiomyocyte apoptosis. Mechanistically, we demonstrated that GDF11 alleviated high glucose-induced cardiomyocytes apoptosis by inhibiting the activation of the alkylation repair homolog 5 (ALKBH5)-forkhead box group O3a (FOXO3)-cerebellar degeneration-related protein 1 transcript (CDR1as)/Hippo signaling pathway. Consequently, this novel mechanism effectively counteracted myocardial cell apoptosis, providing valuable insights into potential therapeutic strategies for clinical diabetic cardiomyopathy.

Circulating Growth Differentiation Factors 11 and 8, Their Antagonists Follistatin and Follistatin-Like-3, and Risk of Heart Failure in Elders.

Jorge R Kizer, Sheena Patel, Peter Ganz +9 more

Heterochronic parabiosis has identified growth differentiation factor (GDF)-11 as a potential means of cardiac rejuvenation, but findings have been inconsistent. A major barrier has been lack of assay specificity for GDF-11 and its homolog GDF-8.

Functional substitutions of amino acids that differ between GDF11 and GDF8 impact skeletal development and skeletal muscle.

John Lian, Ryan G Walker, Andrea D'Amico +11 more

Growth differentiation factor 11 (GDF11) and GDF8 (MSTN) are closely related TGF-β family proteins that interact with nearly identical signaling receptors and antagonists. However, GDF11 appears to activate SMAD2/3 more potently than GDF8 in vitro and in vivo. The ligands possess divergent structural properties, whereby substituting unique GDF11 amino acids into GDF8 enhanced the activity of the resulting chimeric GDF8. We investigated potentially distinct endogenous activities of GDF11 and GDF8 in vivo by genetically modifying their mature signaling domains. Full recoding of GDF8 to that of GDF11 yielded mice lacking GDF8, with GDF11 levels ∼50-fold higher than normal, and exhibiting modestly decreased muscle mass, with no apparent negative impacts on health or survival. Substitution of two specific amino acids in the fingertip region of GDF11 with the corresponding GDF8 residues resulted in prenatal axial skeletal transformations, consistent with Gdf11-deficient mice, without apparent perturbation of skeletal or cardiac muscle development or homeostasis. These experiments uncover distinctive features between the GDF11 and GDF8 mature domains in vivo and identify a specific requirement for GDF11 in early-stage skeletal development.

Growth differentiation factor 11: A proangiogenic drug as a potential antiaging regulating molecule.

Luc Rochette, Geoffrey Dogon, Eve Rigal +3 more

Organs and tissues are subjected to numerous alterations during aging, as a result of complex biochemical changes. Aging is certainly associated with the accumulation of "antiaging" and "proaging" factors in the systemic circulation. The effects of young blood on rejuvenation of regenerative capacity suggest the existence of multiple "proyouthful" factors, such as growth differentiation factor 11 (GDF11), in the young blood of animals. GDF11 is a member of the transforming growth factor beta (TGFβ) superfamily of cytokines, and appears to be a critical rejuvenation factor in aging organs. In the context of aging, GDF11 promotes vascular and neural plasticity of the central nervous system. Parabiosis, the surgical linking of circulations between old and young mice, was employed to identify GDF11 as an antihypertrophic factor that appears to rejuvenate the aging murine heart. Current theories suggest that GDF11 in young blood has beneficial effects on cognitive and cardiovascular functions and wound healing. The cellular mechanisms of GDF11 in cardiovascular, neurological, skin and skeletal muscle diseases are not clearly defined, but evidence indicates that it may function as a proneurogenic and proangiogenic drug. GDF11 binds and activates specific receptor complexes, which transmit signals by two procedures: the TGFβ-Smad pathway and the bone morphogenic protein (BMP)-Smad pathway. GDF11 is perhaps only the first in a series of circulating molecules that will be found to influence the aging of different tissues, and it may be a potential candidate for therapeutic intervention against angiogenesis-related disorders.

N-glycosylation-mediated CD147 accumulation induces cardiac fibrosis in the diabetic heart through ALK5 activation.

Mingchuan Liu, Tingwei Peng, Lang Hu +9 more

Emerging evidence has implicated the important role of fibrosis in diabetic cardiomyopathy (DCM), while the underlying mechanism remains unclear. Considering the distinct and overlapping roles of Cluster of Differentiation 147 (CD147) in the pathogenesis of fibrotic diseases, we aim to investigate the role of CD147 in the fibrosis of DCM and explore its underlying mechanism. AAV9-mediated cardiac-specific CD147 silencing attenuated cardiac fibrosis and cardiac function in diabetic mice. CD147 knockdown significantly inhibited high glucose (HG)-induced activation of CFs. Mechanistically, CD147 directly bound to type I transcription growth factor β (TGF-β) receptor I (ALK5), promoting ALK5 activation and endocytosis to induce SMAD2/3 phosphorylation and nuclear translocation. In addition, HG prevented the ubiquitin-proteasome-dependent degradation of CD147 by promoting GNT-V-mediated N-glycosylation. As a result, cardiac-specific CD147 overexpression in control mice mimicked diabetes-induced cardiac fibrosis, aggravating cardiac function. Importantly, CD147 was also upregulated in serum and myocardial specimens from patients with diabetes compared with non-diabetes, accompanied by echocardiographic indices of cardiac dysfunction and excessive collagen deposition. Our study provides the first evidence that CD147 acts as a pivotal factor to promote diabetic cardiac fibrosis, and may contribute to the development of future CD147-based therapeutic strategies for DCM.

GDF11 Regulates PC12 Neural Stem Cells via ALK5-Dependent PI3K-Akt Signaling Pathway.

Zongkui Wang, Peng Jiang, Fengjuan Liu +9 more

Growth differentiation factor 11 (GDF11), belonging to the transforming factor-β superfamily, regulates anterior-posterior patterning and inhibits neurogenesis during embryonic development. However, recent studies recognized GDF11 as a rejuvenating (or anti-ageing) factor to reverse age-related cardiac hypertrophy, repair injured skeletal muscle, promote cognitive function, etc. The effects of GDF11 are contradictory and the mechanism of action is still not well clarified. The objective of the present study was to investigate effects of GDF11 on PC12 neural stem cells in vitro and to reveal the underlying mechanism. We systematically assessed the effects of GDF11 on the life activities of PC12 cells. GDF11 significantly suppressed cell proliferation and migration, promoted differentiation and apoptosis, and arrested cell cycle at G2/M phase. Both TMT-based proteomic analysis and phospho-antibody microarray revealed PI3K-Akt pathway was enriched when treated with GDF11. Inhibition of ALK5 or PI3K obviously attenuated the effects of GDF11 on PC12 neural stem cells, which exerted that GDF11 regulated neural stem cells through ALK5-dependent PI3K-Akt signaling pathway. In summary, these results demonstrated GDF11 could be a negative regulator for neurogenesis via ALK5 activating PI3K-Akt pathway when it directly acted on neural stem cells.

Knockdown of HIPK2 Attenuates Angiotensin II-Induced Cardiac Fibrosis in Cardiac Fibroblasts.

Feng Xu, Bingbing Mao, Yan Li +1 more

Homeodomain-interacting protein kinase-2 (HIPK2), a member of an evolutionary conserved family of serine/threonine kinases, has been observed to be involved in the pathogenesis of fibrotic diseases. However, its role in cardiac fibrosis remains unclear. In this study, we assessed the effect of HIPK2 on cardiac fibroblasts (CFs) in response to angiotensin II (Ang II) stimulation. The results indicated that HIPK2 expression was significantly increased in Ang II-induced CFs in a dose-dependent manner. Then, HIPK2 was knocked down in CFs to evaluate the roles of HIPK2. Knockdown of HIPK2 suppressed cell proliferation and migration in Ang II-induced CFs. The Ang II-caused increase in expression of α-smooth muscle actin, a hallmark of myofibroblast differentiation, was decreased by knockdown of HIPK2. HIPK2 knockdown also reduced extracellular matrix production including type I collagen and connective tissue growth factor. Furthermore, knockdown of HIPK2 blocked the activation of TGF-β1/Smad pathway in Ang II-induced CFs. These data suggested that HIPK2 knockdown prevented the Ang II-induced activation of CFs through inhibiting TGF-β1/Smad pathway, indicating HIPK2 might be an antifibrosis target for the treatment of cardiac fibrosis.

Lefty1 Ameliorates Post-infarction Fibrosis by Suppressing p-Smad2 and p-ERK1/2 Signaling Pathways.

Chang-Yi Li, Jing-Rui Zhang, Xin-Xin Li +4 more

Transforming growth factor-β1 signaling pathways are known to involve in the development of post-infarction fibrosis, a process characterized by the aberrant activation, proliferation, and differentiation of fibroblasts, as well as the unbalanced turnover of extracellular matrix proteins. Recent studies have shown that Lefty1, a novel member of TGF-β superfamily, acts as a brake on the TGF-β signaling pathway in non-cardiac tissues. However, its role in myocardial infarction (MI)-induced fibrosis and left ventricular remodeling has not been fully elucidated. Here, for the first time, we reported that Lefty1 alleviated post-MI fibroblast proliferation, differentiation, and secretion through suppressing p-Smad2 and p-ERK1/2 signaling pathways in vivo and in vitro. In MI mice or TGF-β1-treated neonatal rat cardiac fibroblasts (CFBs), the expression of Lefty1 was upregulated. Adenovirus-mediated overexpression of Lefty1 significantly attenuated TGF-β1-induced CFBs' proliferation, differentiation, and collagen production. Using the adeno-associated virus approach, we confirmed that Lefty1 attenuates MI-induced cardiac injury, as evidenced by the decreased infarct size and preserved cardiac function. These results highlight the importance of Lefty1 in the prevention of post-MI fibrosis and may help identify potential targets for therapeutic intervention of cardiac fibrosis. Graphical abstract.

E2F transcription factor 1 (E2F1) promotes the transforming growth factor TGF-β1 induced human cardiac fibroblasts differentiation through promoting the transcription of CCNE2 gene.

Rongheng Liao, Bo Xie, Jun Cui +3 more

The differentiation of cardiac fibroblast to myofibroblast is the key process of cardiac fibrosis. In the study, we aimed to determine the function of E2F Transcription Factor 1 (E2F1) in human cardiac fibroblasts (HCFs) differentiation, search for its downstream genes and elucidate the function of them in HCFs differentiation. As a result, we found that E2F1 was up-regulated in TGF-β1-induced HCFs differentiation. Silencing the expression of E2F1 by siRNA in HCFs, we found that the expression of differentiation-related genes (Collagen-1, α-Smooth muscle actin, and Fibronectin-1) was significantly suppressed, combining with proliferation and migration assay, we determined that HCFs differentiation was decreased. Luciferase report assay and immunoprecipitation proved that the oncogene CCNE2 was a direct target gene of E2F1, overexpression of CCNE2 was found in differentiated HCFs, silencing the expression of CCNE2 by siRNA decreased HCFs differentiation. Our research suggested that E2F1 and its downstream target gene CCNE2 play a vital role in TGF-β1-induced HCFs differentiation, thus E2F1 and CCNE2 may be a potential therapeutic target for cardiac fibrosis.

Growth differentiation factor 11 mitigates cardiac radiotoxicity via activating AMPKα.

Xia Li, Dong Ding, Wei Chen +3 more

Cardiac radiotoxicity largely impedes the therapeutic benefits of radiotherapy to malignancies. Growth differentiation factor 11 (GDF11) is implicated in the pathogenesis of cardiac diseases under different pathological conditions. This study aims to investigate the role and underlying mechanisms of GDF11 on cardiac radiotoxicity. Mice were injected with cardiotropic adeno-associated virus 9 carrying the full-length mouse GDF11 gene or negative control under a cTnT promoter from the tail vein, and then received a single dose of 20 Gray (Gy) whole-heart irradiation (WHI) for 16 weeks to imitate cardiac radiotoxicity. Compound C (CC, 20 mg/kg) was intraperitoneally injected every two days at 1 week before WHI stimulation to inhibit 5' AMP-activated protein kinase α (AMPKα). Cardiac GDF11 expression was significantly suppressed at both the protein and mRNA levels. GDF11 overexpression decreased oxidative stress, apoptosis, and fibrosis in radiated hearts, thereby mitigating cardiac radiotoxicity, and dysfunction. Further detection revealed that GDF11 activated AMPKα to reduce radiation-induced oxidative damage and that AMPKα inhibition by CC offset the cardioprotective effects by GDF11. GDF11 mitigates cardiac radiotoxicity via activating AMPKα and it is a promising candidate to treat cardiac radiotoxicity.

A new model of myofibroblast-cardiomyocyte interactions and their differences across species.

Fusheng Liu, Hou Wu, Xiaoyu Yang +5 more

Although coupling between cardiomyocytes and myofibroblasts is well known to affect the physiology and pathophysiology of cardiac tissues across species, relating these observations to humans is challenging because the effect of this coupling varies across species and because the sources of these effects are not known. To identify the sources of cross-species variation, we built upon previous mathematical models of myofibroblast electrophysiology and developed a mechanoelectrical model of cardiomyocyte-myofibroblast interactions as mediated by electrotonic coupling and transforming growth factor-β1. The model, as verified by experimental data from the literature, predicted that both electrotonic coupling and transforming growth factor-β1 interaction between myocytes and myofibroblast prolonged action potential in rat myocytes but shortened action potential in human myocytes. This variance could be explained by differences in the transient outward K+ current associated with differential Kv4.2 gene expression across species. Results are useful for efforts to extrapolate the results of animal models to the predicted effects in humans and point to potential therapeutic targets for fibrotic cardiomyopathy.

Myokines and Heart Failure: Challenging Role in Adverse Cardiac Remodeling, Myopathy, and Clinical Outcomes.

Alexander E Berezin, Alexander A Berezin, Michael Lichtenauer

Heart failure (HF) is a global medical problem that characterizes poor prognosis and high economic burden for the health system and family of the HF patients. Although modern treatment approaches have significantly decreased a risk of the occurrence of HF among patients having predominant coronary artery disease, hypertension, and myocarditis, the mortality of known HF continues to be unacceptably high. One of the most important symptoms of HF that negatively influences tolerance to physical exercise, well-being, social adaptation, and quality of life is deep fatigue due to HF-related myopathy. Myopathy in HF is associated with weakness of the skeletal muscles, loss of myofibers, and the development of fibrosis due to microvascular inflammation, metabolic disorders, and mitochondrial dysfunction. The pivotal role in the regulation of myocardial and skeletal muscle rejuvenation, attenuation of muscle metabolic homeostasis, and protection against ischemia injury and apoptosis belongs to myokines. Myokines are defined as a wide spectrum of active molecules that are directly synthesized and released by both cardiac and skeletal muscle myocytes and regulate energy homeostasis in autocrine/paracrine manner. In addition, myokines have a large spectrum of pleiotropic capabilities that are involved in the pathogenesis of HF including cardiac remodeling, muscle atrophy, and cardiac cachexia. The aim of the narrative review is to summarize the knowledge with respect to the role of myokines in adverse cardiac remodeling, myopathy, and clinical outcomes among HF patients. Some myokines, such as myostatin, irisin, brain-derived neurotrophic factor, interleukin-15, fibroblast growth factor-21, and growth differential factor-11, being engaged in the regulation of the pathogenesis of HF-related myopathy, can be detected in peripheral blood, and the evaluation of their circulating levels can provide new insights to the course of HF and stratify patients at higher risk of poor outcomes prior to sarcopenic stage.

Growth differentiation factor 11 attenuates cardiac ischemia reperfusion injury via enhancing mitochondrial biogenesis and telomerase activity.

Lin Chen, Guangjin Luo, Yameng Liu +13 more

It has been reported that growth differentiation factor 11 (GDF11) protects against myocardial ischemia/reperfusion (IR) injury, but the underlying mechanisms have not been fully clarified. Considering that GDF11 plays a role in the aging/rejuvenation process and that aging is associated with telomere shortening and cardiac dysfunction, we hypothesized that GDF11 might protect against IR injury by activating telomerase. Human plasma GDF11 levels were significantly lower in acute coronary syndrome patients than in chronic coronary syndrome patients. IR mice with myocardial overexpression GDF11 (oe-GDF11) exhibited a significantly smaller myocardial infarct size, less cardiac remodeling and dysfunction, fewer apoptotic cardiomyocytes, higher telomerase activity, longer telomeres, and higher ATP generation than IR mice treated with an adenovirus carrying a negative control plasmid. Furthermore, mitochondrial biogenesis-related proteins and some antiapoptotic proteins were significantly upregulated by oe-GDF11. These cardioprotective effects of oe-GDF11 were significantly antagonized by BIBR1532, a specific telomerase inhibitor. Similar effects of oe-GDF11 on apoptosis and mitochondrial energy biogenesis were observed in cultured neonatal rat cardiomyocytes, whereas GDF11 silencing elicited the opposite effects to oe-GDF11 in mice. We concluded that telomerase activation by GDF11 contributes to the alleviation of myocardial IR injury through enhancing mitochondrial biogenesis and suppressing cardiomyocyte apoptosis.

GDF11 Alleviates Pathological Myocardial Remodeling in Diabetic Cardiomyopathy Through SIRT1-Dependent Regulation of Oxidative Stress and Apoptosis.

Han-Zhao Zhu, Li-Yun Zhang, Meng-En Zhai +14 more

Growth differentiation factor 11 (GDF11) is a member of the transforming growth factor β superfamily that alleviates cardiac hypertrophy, myocardial infarction, and vascular injury by regulating oxidative stress, inflammation, and cell survival. However, the roles and underlying mechanisms of GDF11 in diabetic cardiomyopathy (DCM) remain largely unknown. In this study, we sought to determine whether GDF11 could prevent DCM. After establishing a mouse model of diabetes by administering a high-fat diet and streptozotocin, intramyocardial injection of an adeno-associated virus was used to achieve myocardium-specific GDF11 overexpression. GDF11 remarkably improved cardiac dysfunction and interstitial fibrosis by reducing the levels of reactive oxygen species and protecting against cardiomyocyte loss. Mechanistically, decreased sirtuin 1 (SIRT1) expression and activity were observed in diabetic mice, which was significantly increased after GDF11 overexpression. To further explore how SIRT1 mediates the role of GDF11, the selective inhibitor EX527 was used to block SIRT1 signaling pathway, which abolished the protective effects of GDF11 against DCM. In vitro studies confirmed that GDF11 protected against H9c2 cell injury in high glucose and palmitate by attenuating oxidative injury and apoptosis, and these effects were eliminated by SIRT1 depletion. Our results demonstrate for the first time that GDF11 protects against DCM by regulating SIRT1 signaling pathway.

PPARα Targeting GDF11 Inhibits Vascular Endothelial Cell Senescence in an Atherosclerosis Model.

Fangfang Dou, Beiling Wu, Jiulin Chen +3 more

Atherosclerosis (AS) is a complex vascular disease that seriously harms the health of the elderly. It is closely related to endothelial cell aging, but the role of senescent cells in atherogenesis remains unclear. Studies have shown that peroxisome proliferator-activated receptor alpha (PPARα) inhibits the development of AS by regulating lipid metabolism. Our previous research showed that PPARα was involved in regulating the repair of damaged vascular endothelial cells. Using molecular biology and cell biology approaches to detect senescent cells in atherosclerosis-prone apolipoprotein E-deficient (Apoe -/-) mice, we found that PPARα delayed atherosclerotic plaque formation by inhibiting vascular endothelial cell senescence, which was achieved by regulating the expression of growth differentiation factor 11 (GDF11). GDF11 levels declined with age in several organs including the myocardium, bone, central nervous system, liver, and spleen in mice and participated in the regulation of aging. Our results showed that PPARα inhibited vascular endothelial cell senescence and apoptosis and promoted vascular endothelial cell proliferation and angiogenesis by increasing GDF11 production. Taken together, these results demonstrated that PPARα inhibited vascular endothelial cell aging by promoting the expression of the aging-related protein GDF11, thereby delaying the occurrence of AS.

Protocatechuic acid attenuates angiotensin II-induced cardiac fibrosis in cardiac fibroblasts through inhibiting the NOX4/ROS/p38 signaling pathway.

Hui Song, Jie Ren

Cardiac fibrosis plays a crucial role in the pathogenesis of myocardial infarction (MI). It has been found that differentiation of cardiac fibroblasts (CFs) into myofibroblasts is a major event in the process of cardiac fibrosis. In the present study, we aimed to investigate the effects of protocatechuic acid (PCA), a cardiac protective agent, on the CFs differentiation in vitro. The results showed that PCA exhibited inhibitory effects on the cell proliferation and migration in angiotensin II (Ang II)-induced CFs. PCA treatment suppressed the Ang II-induced expression of α-smooth muscle actin (α-SMA), which is a hallmark of myofibroblasts. In addition, the production of extracellular matrix (ECM) proteins, including type I collagen (Col I) and connective tissue growth factor (CTGF), were significantly decreased in the PCA-treated CFs. The Ang II-induced increased levels of matrix metalloproteinase (MMP)-2, and MMP-9 were reduced by PCA. Furthermore, PCA resulted in decrease in reactive oxygen species (ROS) generation, as well as the expressions of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase enzyme 4 (NOX4) and p-p38 in Ang II-induced CFs. These findings showed that PCA treatment prevented the Ang II-induced cardiac fibrosis by inhibiting the NOX4/ROS/p38 signaling pathway in vitro, suggesting that PCA might be a therapeutic agent for MI.