Cell senescence is involved in the process of organ damage and repair; however, the underlying molecular mechanism needs to be further explored.

Human heart failure is a complex syndrome and a primary cause of morbidity and mortality in the world. However, the molecular pathways involved in the remodelling process are poorly understood. In this study, we performed exhaustive global proteomic surveys of cardiac ventricle isolated from failing and non-failing human hearts, and determined the regulatory pathway to uncover the mechanism underlying heart failure. Two-dimensional gel electrophoresis (2-DE) coupled with tandem mass spectrometry was used to identify differentially expressed proteins in specimens from failing (n = 9) and non-failing (n = 6) human hearts. A total of 25 proteins with at least 1.5-fold change in the failing heart were identified; 15 proteins were up-regulated and 10 proteins were down-regulated. The altered proteins belong to three broad functional categories: (i) metabolic [e.g. NADH dehydrogenase (ubiquinone), dihydrolipoamide dehydrogenase, and the cytochrome c oxidase subunit]; (ii) cytoskeletal (e.g. myosin light chain proteins, troponin I type 3 and transthyretin) and (iii) stress response (e.g. αB-crystallin, HSP27 and HSP20). The marked differences in the expression of selected proteins, including HSP27 and HSP20, were further confirmed by Western blot. Thus, we carried out full-scale screening of the protein changes in human heart failure and profiled proteins that may be critical in cardiac dysfunction for future mapping.

Neutrophils consume a large amount of energy when performing their functions. Compared with other white blood cells, neutrophils contain few mitochondria and mainly rely on glycolysis and gluconeogenesis to produce ATP. The inflammatory site is hypoxic and nutrient poor. Our aim is to study the role of abnormal adenosine metabolism of neutrophils in the asthmatic airway inflammation microenvironment.

Marfan syndrome (MFS) is an autosomal dominant genetic disorder of the connective tissue, typically characteristic of cardiovascular manifestations, valve prolapse, left ventricle enlargement, and cardiac failure. Fibrillin-1 (FBN1) is the causative gene in the pathogenesis of MFS. Patients with different FBN1 mutations often present more considerable phenotypic variation. In the present study, three affected MFS pedigrees were collected for genetic analysis. Using next-generation sequencing (NGS) technologies, 3 novel frameshift pathogenic mutations which are cosegregated with affected subjects in 3 pedigrees were identified. These novel mutations provide important diagnostic and therapeutic insights for precision medicine in MFS, especially regarding the lethal cardiovascular events.

Tissue damage and its associated-inflammation act as tumour initiators or propagators. AMP-activated protein kinase (AMPK) is activated by environmental or nutritional stress factors, such as hypoxia, glucose deprivation, and other cell injury factors, to regulate cell energy balance and differentiation. We previously have reported that AMPKα2 deficiency resulted in the energy deprivation in tumour-bearing liver and the enhanced-hepatocyte death. In this study, AMPKα2 knockout mice and the liver metastasis model of colon cancer cells were used to address the role of AMPKα isoforms in tumour inflammation. First, we found that the AMPKα2 deficiency exacerbated the liver injury and recruitment of macrophages. Meanwhile, although compensatory expression of AMPKα1 was not significant after AMPKα2 knockout, AMPKα1 phosphorylation was elevated in remnant liver in AMPKα2 knockout mice, which was positively associated with the enhanced energy deprivation in the AMPKα2 deficient mice. Furthermore, the activated AMPKα1 in macrophage contributed to its polarizing to tumour-associated phenotype. Thus, the enhanced tumour-associated inflammation and activation of AMPKα1 in the AMPKα2 deficient mice may exacerbate the tumour development by affecting the tumour inflammatory microenvironment. Our study suggests that the two isoforms of AMPKα, AMPKα1 and AMPKα2 play different roles in controlling tumour development.

After injury, the coordinated balance of pro- and anti-inflammatory factors in the microenvironment contribute to skeletal muscle regeneration. However, the underlying molecular mechanisms regulating this balance remain incompletely understood. In this study, we examined the roles of microRNAs (miRNAs) in inflammation and muscle regeneration. miRNA-Seq transcriptome analysis of mouse skeletal muscle revealed that miR-223-3p is upregulated in the early stage of muscle regeneration after injury. miR-223-3p knockout resulted in increased inflammation, impaired muscle regeneration, and increased interstitial fibrosis. Mechanistically, we found that myeloid-derived miR-223-3p suppresses the target gene interleukin-6 (Il6), associated with the maintenance of the proinflammatory macrophage phenotype during injury. Administration of IL-6-neutralizing antibody in miR-223-3p-knockout muscle could rescue the impaired regeneration ability and reduce the fibrosis. Together, our results reveal that miR-223-3p improves muscle regeneration by regulating inflammation, indicating that miRNAs can participate in skeletal muscle regeneration by controlling the balance of pro- and anti-inflammatory factors in the skeletal muscle microenvironment.

Obstructive nephropathy is an aggressive form of chronic kidney disease (CKD), which is characterized by an epithelial-to-mesenchymal transition (EMT) and interstitial fibrosis. However, the molecular mechanisms of EMT and fibrosis are complex and not fully understood. In this study, we investigated the contribution of Akt2 to experimental renal EMT and fibrosis using the well-established model of unilateral ureteral obstruction (UUO). We found that Akt2 and phosphor (p)-Akt protein levels were increased in the obstructed kidneys. UUO induced activation of transforming growth factor-β1 (TGF-β1) signaling. Importantly, knockout of Akt2 suppressed UUO-induced EMT, kidney fibrosis, increased GSK3β activity, and decreased expression of Snail and β-catenin. Inhibition of GSK3β with LiCl (the inhibitor of GSK3β) increased the expression of Snail and β-catenin in cultured kidney epithelial cells. Our findings suggest that Akt2 partially contributes to interstitial fibrosis following UUO and that inhibition of this signaling pathway may provide a novel approach of prevent progression of renal fibrosis.

Vascular calcification is the ectopic deposition of calcium hydroxyapatite minerals in arterial wall, which involves the transdifferentiation of vascular smooth muscle cells (VSMCs) toward an osteogenic phenotype. However, the underlying molecular mechanisms regulating the VSMC osteogenic switch remain incompletely understood. In this study, we examined the roles of microRNAs (miRNAs) in vascular calcification. miRNA-seq transcriptome analysis identified miR-223-3p as a candidate miRNA in calcified mouse aortas. MiR-223-3p knockout aggravated calcification in both medial and atherosclerotic vascular calcification models. Further, RNA-seq transcriptome analysis verified JAK-STAT and PPAR signaling pathways were upregulated in both medial and atherosclerotic calcified aortas. Overlapping genes in these signaling pathways with predicted target genes of miR-223-3p derived from miRNA databases, we identified signal transducer and activator of transcription 3 (STAT3) as a potential target gene of miR-223-3p in vascular calcification. In vitro experiments showed that miR-223-3p blocked interleukin-6 (IL-6)/STAT3 signaling, thereby preventing the osteogenic switch and calcification of VSMCs. In contrast, overexpression of STAT3 diminished the effect of miR-223-3p. Taken together, the results indicate a protective role of miR-223-3p that inhibits both medial and atherosclerotic vascular calcification by regulating IL-6/STAT3 signaling-mediated VSMC transdifferentiation.

In this study, we assessed whether the down-regulation of Yes-associated protein (YAP) is involved in the pathogenesis of extracellular matrix (ECM) mechanical stress-induced Stanford type A aortic dissection (STAAD). Human aortic samples were obtained from heart transplantation donors as normal controls and from STAAD patients undergoing surgical replacement of the ascending aorta. Decreased maximum aortic wall velocity, ECM disorders, increased VSMC apoptosis, and YAP down-regulation were identified in STAAD samples. In a mouse model of STAAD, YAP was down-regulated over time during the development of ECM damage, and increased VSMC apoptosis was also observed. YAP knockdown induced VSMC apoptosis under static conditions in vitro, and the change in mechanical stress induced YAP down-regulation and VSMC apoptosis. This study provides evidence that YAP down-regulation caused by the disruption of mechanical stress is associated with the development of STAAD via the induction of apoptosis in aortic VSMCs. As STAAD is among the most elusive and life-threatening vascular diseases, better understanding of the molecular pathogenesis of STAAD is critical to improve clinical outcome.

Thoracic aortic dissection (TAD) is characterized by an inflammatory response. Angiopoietin-like protein 8 (ANGPTL8) is a hormone involved in the regulation of lipid metabolism and inflammation. However, the relationship between ANGPTL8 and TAD remains unknown.

Impaired muscle regeneration and increased muscle fibrosis are observed in aged muscle accompanied by progressive loss of muscle mass (sarcopenia). However, the underlying mechanism is still unclear.

The heart undergoes pathological remodelling under increased stress and neuronal imbalance. MicroRNAs (miRNAs) are involved in post-transcriptional regulation of genes in cardiac physiology and pathology. However, the mechanisms underlying miRNA-mediated regulation of pathological cardiac remodelling remain to be studied. This study aimed to explore the function of endogenous microRNA-27b-3p (miR-27b-3p) in pathological cardiac remodelling.

Background: The prognosis of pediatric dilated cardiomyopathy (PDCM) is highly variable, ranging from death to cardiac function recovery. Left ventricular reverse remodeling (LVRR) represents a favorable prognosis in PDCM. Disturbance of lipid metabolism is associated with the change of cardiac function, but no studies have examined lipidomics data and LVRR. Methods: Discovery analyses were based on 540 targeted lipids in an observational, prospective China-AOCC (An Integrative-Omics Study of Cardiomyopathy Patients for Diagnosis and Prognosis in China) study. The OPLS-DA and random forest (RF) analysis were used to screen the candidate lipids. Associations of the candidate lipids were examined in Cox proportional hazards regression models. Furthermore, we developed a risk score comprising the significant lipids, with each attributed a score of 1 when the concentration was above the median. All significant findings were replicated in a validation set of the China-AOCC study. Results: There were 59 patients in the discovery set and 24 patients in the validation set. LVRR was observed in 27 patients (32.5%). After adjusting for age, left ventricular ejection fraction (LVEF), and left ventricular end-diastolic dimension (LVEDD) z-score, lysophosphatidic acids (LysoPA) 16:0, LysoPA 18:2, LysoPA 18:1, and LysoPA 18:0 were significantly associated with LVRR in the discovery set, and hazard ratios (HRs) were 2.793 (95% CI, 1.545-5.048), 2.812 (95% CI, 1.542-5.128), 2.831 (95% CI, 1.555-5.154), and 2.782 (95% CI, 1.548-5.002), respectively. We developed a LysoPA score comprising the four LysoPA. When the LysoPA score reached 4, LVRR was more likely to be observed in both sets. The AUC increased with the addition of the LysoPA score to the LVEDD z-score (from 0.693 to 0.875 in the discovery set, from 0.708 to 0.854 in the validation set) for prediction of LVRR. Conclusions: Serum LysoPA can predict LVRR in PDCM patients. When the LysoPA score was combined with the LVEDD z-score, it may help in ascertaining the prognosis and monitoring effects of anti-heart failure pharmacotherapy.

Immune cell infiltration in response to myocyte death regulates extracellular matrix remodeling and scar formation after myocardial infarction (MI). Caspase-recruitment domain family member 9 (CARD9) acts as an adapter that mediates the transduction of pro-inflammatory signaling cascades in innate immunity; however, its role in cardiac injury and repair post-MI remains unclear. We found that Card9 was one of the most upregulated Card genes in the ischemic myocardium of mice. CARD9 expression increased considerably 1 day post-MI and declined by day 7 post-MI. Moreover, CARD9 was mainly expressed in F4/80-positive macrophages. Card9 knockout (KO) led to left ventricular function improvement and infarct scar size reduction in mice 28 days post-MI. Additionally, Card9 KO suppressed cardiomyocyte apoptosis in the border region and attenuated matrix metalloproteinase (MMP) expression. RNA sequencing revealed that Card9 KO significantly suppressed lipocalin 2 (Lcn2) expression post-MI. Both LCN2 and the receptor solute carrier family 22 member 17 (SL22A17) were detected in macrophages. Subsequently, we demonstrated that Card9 overexpression increased LCN2 expression, while Card9 KO inhibited necrotic cell-induced LCN2 upregulation in macrophages, likely through NF-κB. Lcn2 KO showed beneficial effects post-MI, and recombinant LCN2 diminished the protective effects of Card9 KO in vivo. Lcn2 KO reduced MMP9 post-MI, and Lcn2 overexpression increased Mmp9 expression in macrophages. Slc22a17 knockdown in macrophages reduced MMP9 release with recombinant LCN2 treatment. In conclusion, our results demonstrate that macrophage CARD9 mediates the deterioration of cardiac function and adverse remodeling post-MI via LCN2.

Abdominal aortic aneurysm (AAA) is a life-threatening aortic disease in the elderly. Activation of Notch1 pathway plays a critical role in the development of AAA, but the underlying mechanisms remain poorly understood. In the present study, we explored the mechanisms by which Notch1 activation regulates angiotensin II (Ang II)-induced AAA formation and evaluated the therapeutic potential of a new Notch γ-secretase inhibitor, dibenzazepine (DBZ), for the treatment of AAA. Apolipoprotein E knockout (Apo E(-/-)) mice infused for 4 weeks with Ang II (1000 ng/kg/min, IP) using osmotic mini-pumps were received an intraperitoneal injection of either vehicle or 1 mg/kg/d DBZ. Notch1 signaling was activated in AAA tissue from both Ang II-infused Apo E(-/-) mice and human undergoing AAA repair in vivo, with increased expression of Notch intracellular domain (NICD) and its target gene Hes1, and this effect was effectively blocked by DBZ. Moreover, infusion of Ang II markedly increased the incidence and severity of AAA in Apo E(-/-) mice. In contrast, inhibition of Notch activation by DBZ prevented AAA formation in vivo. Furthermore, DBZ markedly prevented Ang II-stimulated accumulation of macrophages and CD4(+) T cells, and ERK-mediated angiogenesis, simultaneously reversed Th2 response, in vivo. In conclusion, these findings provide new insight into the multiple mechanisms of Notch signaling involved in AAA formation and suggest that γ-secretase inhibitor DBZ might be a novel therapeutic drug for treating AAAS.

In response to pathological stimuli, the heart develops ventricular hypertrophy that progressively decompensates and leads to heart failure. miRNAs are increasingly recognized as pathogenic factors, clinically relevant biomarkers, and potential therapeutic targets. We identified that mir15a/mir16-1 cluster was negatively correlated with hypertrophic severity in patients with hypertrophic cardiomyopathy. The mir15a/mir16-1 expression was enriched in cardiomyocytes (CMs), decreased in hypertrophic human hearts, and decreased in mouse hearts after transverse aortic constriction (TAC). CM-specific mir15a/mir16-1 knockout promoted cardiac hypertrophy and dysfunction after TAC. CCAAT/enhancer binding protein (C/EBP)β was responsible for the downregulation of mir15a/mir16-1 cluster transcription. Mechanistically, mir15a/mir16-1 cluster attenuated the insulin/IGF1 signal transduction cascade by inhibiting multiple targets, including INSR, IGF-1R, AKT3, and serum/glucocorticoid regulated kinase 1 (SGK1). Pro-hypertrophic response induced by mir15a/mir16-1 inhibition was abolished by knockdown of insulin receptor (INSR), insulin like growth factor 1 receptor (IGF1R), AKT3, or SGK1. In vivo systemic delivery of mir15a/mir16-1 by nanoparticles inhibited the hypertrophic phenotype induced by TAC. Importantly, decreased serum mir15a/mir16-1 levels predicted the occurrence of left ventricular hypertrophy in a cohort of patients with hypertension. Therefore, mir15a/mir16-1 cluster is a promising therapeutic target and biomarker for cardiac hypertrophy.

Regeneration of skeletal muscle following injury is accompanied by transient inflammation. Here we show that complement is activated in skeletal muscle injury and plays a key role during regeneration. Genetic ablation of complement C3 or its inactivation with Cobra Venom Factor (CVF) result in impaired muscle regeneration following cardiotoxin-induced injury in mice. The effect of complement in muscle regeneration is mediated by the alternative pathway and C3a receptor (C3aR) signaling, as deletion of Cfb, a key alternative pathway component, or C3aR leads to impaired regeneration and reduced monocyte/macrophage infiltration. Monocytes from C3aR-deficient mice express a reduced level of adhesion molecules, cytokines and genes associated with antigen processing and presentation. Exogenous administration of recombinant CCL5 to C3aR-deficient mice rescues the defects in inflammatory cell recruitment and regeneration. These findings reveal an important role of complement C3a in skeletal muscle regeneration, and suggest that manipulating complement system may produce therapeutic benefit in muscle injury and regeneration.

The most well-known cause of chemotherapy-induced cardiotoxicity is doxorubicin (DOX). The ubiquitin-proteasome system (UPS) is the main cellular machinery for protein degradation in eukaryotic cells. However, the expression pattern of the UPS in DOX-induced cardiotoxicity remains unclear. C57BL/6 mice were intraperitoneally injected with a single dose of DOX (15mg/kg). After 1, 3 and 5 days, cardiac function and apoptosis were detected with echocardiography and TUNEL assay. Microarray assay and qPCR analysis were also performed at day 5. We found that DOX caused a significant decrease in cardiac function at day 5 and increase in cardiomyocyte apoptosis at days 3 and 5. Microarray data revealed that totally 1185 genes were significantly regulated in DOX-treated heart, and genes involved in apoptosis and the UPS were mostly altered. Among them, the expression of 3 immunoproteasome catalytic subunits (β1i, β2i and β5i) was markedly down-regulated. Moreover, DOX significantly decreased proteasome activities and enhanced polyubiquitinated proteins in the heart. Importantly, overexpression of immunoproteasome catalytic subunits (β1i, β2i or β5i) significantly attenuated DOX-induced cardiomyocyte apoptosis and other UPS gene expression while knockdown of them significantly increased DOX-induced cardiomyocyte apoptosis. These effects were partially associated with increased degradation of multiple pro-apoptotic proteins. In conclusion, our studies suggest that immunoproteasome plays an important role in DOX-induced cardiomyocyte apoptosis, and may be a novel therapeutic target for prevention of DOX-induced cardiotoxicity.

Hypertrophic cardiomyopathy (HCM) is a major cause of sudden cardiac death. Mutations in the MYBPC3 gene represent the cause of HCM in ~35% of patients with HCM. However, genetic testing in clinic setting has been limited due to the cost and relatively time-consuming by Sanger sequencing. Here, we developed a HCM Molecular Diagnostic Kit enabling ultra-low-cost targeted gene resequencing in a large cohort and investigated the mutation spectrum of MYBPC3. In a cohort of 114 patients with HCM, a total of 20 different mutations (8 novel and 12 known mutations) of MYBPC3 were identified from 25 patients (21.9%). We demonstrated that the power of targeted resequencing in a cohort of HCM patients, and found that MYBPC3 is a common HCM-causing gene in Chinese patients. Phenotype-genotype analyses showed that the patients with double mutations (n = 2) or premature termination codon mutations (n = 12) showed more severe manifestations, compared with patients with missense mutations (n = 11). Particularly, we identified a recurrent truncation mutation (p.Y842X) in four unrelated cases (4/25, 16%), who showed severe phenotypes, and suggest that the p.Y842X is a frequent mutation in Chinese HCM patients with severe phenotypes.

Successful muscle regeneration following injury is essential for functional homeostasis of skeletal muscles. Krüppel-like factor 15 (KLF15) is a metabolic transcriptional regulator in the muscles. However, little is known regarding its function in muscle regeneration. Here, we examined microarray datasets from the Gene Expression Omnibus database, which indicated downregulated KLF15 in muscles from patients with various muscle diseases. Additionally, we found that Klf15 knockout (Klf15KO) impaired muscle regeneration following injury in mice. Furthermore, KLF15 expression was robustly induced during myoblast differentiation. Myoblasts with KLF15 deficiency showed a marked reduction in their fusion capacity. Unbiased transcriptome analysis of muscles on day 7 postinjury revealed downregulated genes involved in cell differentiation and metabolic processes in Klf15KO muscles. The FK506-binding protein 51 (FKBP5), a positive regulator of myoblast differentiation, was ranked as one of the most strongly downregulated genes in the Klf15KO group. A mechanistic search revealed that KLF15 binds directly to the promoter region of FKBP5 and activates FKBP5 expression. Local delivery of FKBP5 rescued the impaired muscle regeneration in Klf15KO mice. Our findings reveal a positive regulatory role of KLF15 in myoblast differentiation and muscle regeneration by activating FKBP5 expression. KLF15 signaling may be a novel therapeutic target for muscle disorders associated with injuries or diseases.