Frameshift variants in C10orf71 cause dilated cardiomyopathy in human, mouse, and organoid models.

Research advances over the past 30 years have confirmed a critical role for genetics in the etiology of dilated cardiomyopathies (DCMs). However, full knowledge of the genetic architecture of DCM remains incomplete. We identified candidate DCM causal gene, C10orf71, in a large family with 8 patients with DCM by whole-exome sequencing. Four loss-of-function variants of C10orf71 were subsequently identified in an additional group of492 patients with sporadic DCM from 2 independent cohorts. C10orf71 was found to be an intrinsically disordered protein specifically expressed in cardiomyocytes. C10orf71-KO mice had abnormal heart morphogenesis during embryonic development and cardiac dysfunction as adults with altered expression and splicing of contractile cardiac genes. C10orf71-null cardiomyocytes exhibited impaired contractile function with unaffected sarcomere structure. Cardiomyocytes and heart organoids derived from human induced pluripotent stem cells with C10orf71 frameshift variants also had contractile defects with normal electrophysiological activity. A rescue study using a cardiac myosin activator, omecamtiv mecarbil, restored contractile function in C10orf71-KO mice. These data support C10orf71 as a causal gene for DCM by contributing to the contractile function of cardiomyocytes. Mutation-specific pathophysiology may suggest therapeutic targets and more individualized therapy.

Increased Tryptophan Catabolism Provides Predictive Value to Chronic Heart Failure Patients with Low-Grade Inflammation.

Kynurenine to tryptophan ratio (KTR), which serves as an indicator for evaluating indoleamine-2,3-dioxygenase activity and inflammation, has been reported to be linked with cardiovascular incidences. However, its correlation with cardiovascular outcomes in patients suffering from heart failure (HF) remains to be explored. The objective of this study was to investigate the prognostic value of KTR in HF. The concentration of tryptophan and kynurenine were quantified by liquid chromatography-tandem mass spectrometry, and the KTR value was calculated in a population of 3150 HF patients. The correlation between plasma KTR levels and the occurrence of adverse cardiovascular events was evaluated for its prognostic value. We also assessed the role of KTR in addition to the classic inflammatory biomarker hypersensitive C-reactive protein (hs-CRP) in different subtypes of HF. We found that increased KTR levels were associated with an elevated risk and severity of the primary endpoints in different subtypes of HF. The simultaneous evaluation of KTR and hs-CRP levels enhanced risk categorization among HF patients. Furthermore, the KTR index presented complementary prognostic value for those HF patients with low-grade inflammation (hs-CRP ≤ 6 mg/L). Our results indicated plasma KTR is an independent risk factor for cardiovascular events. Plasma KTR levels in patients with HF can provide both concurrent and complementary prognostic value to hs-CRP.

LncRNA DCRT Protects Against Dilated Cardiomyopathy by Preventing NDUFS2 Alternative Splicing by Binding to PTBP1.

BACKGROUND: Dilated cardiomyopathy is characterized by left ventricular dilation and continuous systolic dysfunction. Mitochondrial impairment is critical in dilated cardiomyopathy; however, the underlying mechanisms remain unclear. Here, we explored the cardioprotective role of a heart-enriched long noncoding RNA, the dilated cardiomyopathy repressive transcript (DCRT), in maintaining mitochondrial function. METHODS: The DCRT knockout (DCRT-/-) mice and DCRT knockout cells were developed using CRISPR-Cas9 technology. Cardiac-specific DCRT transgenic mice were generated using α-myosin heavy chain promoter. Chromatin coimmunoprecipitation, RNA immunoprecipitation, Western blot, and isoform sequencing were performed to investigate the underlying mechanisms. RESULTS: We found that the long noncoding RNA DCRT was highly enriched in the normal heart tissues and that its expression was significantly downregulated in the myocardium of patients with dilated cardiomyopathy. DCRT-/- mice spontaneously developed cardiac dysfunction and enlargement with mitochondrial impairment. DCRT transgene or overexpression with the recombinant adeno-associated virus system in mice attenuated cardiac dysfunction induced by transverse aortic constriction treatment. Mechanistically, DCRT inhibited the third exon skipping of NDUFS2 (NADH dehydrogenase ubiquinone iron-sulfur protein 2) by directly binding to PTBP1 (polypyrimidine tract binding protein 1) in the nucleus of cardiomyocytes. Skipping of the third exon of NDUFS2 induced mitochondrial dysfunction by competitively inhibiting mitochondrial complex I activity and binding to PRDX5 (peroxiredoxin 5) and suppressing its antioxidant activity. Furthermore, coenzyme Q10 partially alleviated mitochondrial dysfunction in cardiomyocytes caused by DCRT reduction. CONCLUSIONS: Our study revealed that the loss of DCRT contributed to PTBP1-mediated exon skipping of NDUFS2, thereby inducing cardiac mitochondrial dysfunction during dilated cardiomyopathy development, which could be partially treated with coenzyme Q10 supplementation.

Fibroblast-localized lncRNA CFIRL promotes cardiac fibrosis and dysfunction in dilated cardiomyopathy.

CFIRL is a long noncoding RNA (lncRNA), we previously identified as the most significantly upregulated lncRNA in the failing hearts of patients with dilated cardiomyopathy (DCM). In this study, we determined the function of CFIRL and its role in DCM. Real-time polymerase chain reaction and in situ hybridization assays revealed that CFIRL was primarily localized in the nucleus of cardiac fibroblasts and robustly increased in failing hearts. Global knockdown or fibroblast-specific knockout of CFIRL attenuated transverse aortic constriction (TAC)-induced cardiac dysfunction and fibrosis in vivo. Overexpression of CFIRL in vitro promoted fibroblast proliferation and aggravated angiotensin II-induced differentiation to myofibroblasts. CFIRL knockdown attenuated these effects. Mechanistically, RNA pull-down assay and gene expression profiling revealed that CFIRL recruited ENO1, a newly identified noncanonical transcriptional factor, to activate IL-6 transcription. IL-6 exerted a paracrine effect on cardiomyocytes to promote cardiac hypertrophy, which can be prevented by CFIRL knockdown. These findings uncover the critical role of CFIRL, a fibroblast-associated lncRNA, in heart failure by facilitating crosstalk between fibroblasts and cardiomyocytes. CFIRL knockdown might be a potent strategy to prevent cardiac remodeling in heart failure, particularly in DCM.

lncRNA ZNF593-AS inhibits cardiac hypertrophy and myocardial remodeling by upregulating Mfn2 expression.

lncRNA ZNF593 antisense (ZNF593-AS) transcripts have been implicated in heart failure through the regulation of myocardial contractility. The decreased transcriptional activity of ZNF593-AS has also been detected in cardiac hypertrophy. However, the function of ZNF593-AS in cardiac hypertrophy remains unclear. Herein, we report that the expression of ZNF593-AS reduced in a mouse model of left ventricular hypertrophy and cardiomyocytes in response to treatment with the hypertrophic agonist phenylephrine (PE). In vivo, ZNF593-AS aggravated pressure overload-induced cardiac hypertrophy in knockout mice. By contrast, cardiomyocyte-specific transgenic mice (ZNF593-AS MHC-Tg) exhibited attenuated TAC-induced cardiac hypertrophy. In vitro, vector-based overexpression using murine or human ZNF593-AS alleviated PE-induced myocyte hypertrophy, whereas GapmeR-induced inhibition aggravated hypertrophic phenotypes. By using RNA-seq and gene set enrichment analyses, we identified a link between ZNF593-AS and oxidative phosphorylation and found that mitofusin 2 (Mfn2) is a direct target of ZNF593-AS. ZNF593-AS exerts an antihypertrophic effect by upregulating Mfn2 expression and improving mitochondrial function. Therefore, it represents a promising therapeutic target for combating pathological cardiac remodeling.

Simultaneous quantitative LC-MS/MS analysis of 13 apolipoproteins and lipoprotein (a) in human plasma.

Numerous studies have revealed a close correlation between the levels of apolipoproteins (Apos) (including lipoprotein(a) [Lp(a)]) and an increased risk of cardiovascular disease in recent decades. However, clinically, lipid profiling remains limited to the conventional plasma levels of cholesterol, triglyceride, ApoA1, and ApoB, which brings the necessity to quantify more apolipoproteins in human plasma. In this study, we simultaneously quantified 13 apolipoproteins and Lp(a) in 5 µL of human plasma using the LC-MS/MS platform. A method was developed for the precise detection of Lp(a), ApoA1, A2, A5, B, C1, C2, C3, D, E, H, L1, M, and J. Suitable peptides were selected and optimized to achieve clear separation of each peak. Method validation consisting of linearity, sensitivity, accuracy and precision, recovery, and matrix effects was evaluated. The intra-day CV ranged from 0.58% to 14.2% and the inter-day CV ranged from 0.51% to 13.3%. The recovery rates ranged from 89.8% to 113.7%, while matrix effects ranged from 85.4% to 113.9% for all apolipoproteins and Lp(a). Stability tests demonstrated that these apolipoproteins remained stable for 3 days at 4 °C and 7 days at -20 °C. This validated method was successfully applied to human plasma samples obtained from 45 volunteers. The quantitative results of ApoA1, ApoB, and Lp(a) exhibited a close correlation with the results from the immunity transmission turbidity assay. Collectively, we developed a robust assay that can be used for high-throughput quantification of apolipoproteins and Lp(a) simultaneously for investigating related risk factors in patients with dyslipidemia.

Effects of different treatments for type 2 diabetes mellitus on mortality of coronavirus disease from 2019 to 2021 in China: a multi-institutional retrospective study.

The coronavirus disease (COVID-19) pandemic has continued for 5 years. Sporadic cases continue to occur in different locations. Type 2 diabetes mellitus (T2DM) is associated with a high risk of a poor prognosis in patients with COVID-19. Successful control of blood glucose levels can effectively decrease the risks of severe infections and mortality. However, the effects of different treatments were reported differently and even adversely. This retrospective study included 4,922 patients who have been diagnosed as COVID-19 and T2DM from 138 Hubei hospitals. The clinical characteristics and outcomes were compared and calculated their risk for death using multivariate Cox regression and Kaplan-Meier curves. After adjustment of age, sex, comorbidities, and in-hospital medications, metformin and alpha-glucosidase inhibitor (AGI) use performed lower all-cause mortality (adjusted hazard ratio [HR], 0.41; 95% confidence interval [CI]: 0.24-0.71; p = 0.001 for metformin; 0.53, 0.35-0.80, p = 0.002 for AGIs), while insulin use was associated with increased all-cause mortality (adjusted HR, 2.07, 95% CI, 1.61-2.67, p < 0.001). After propensity score-matched (PSM) analysis, adjusted HRs for insulin, metformin, and AGIs associated with all-cause mortality were 1.32 (95% CI, 1.03-1.81; p = 0.012), 0.48 (95% CI, 0.23-0.83, p = 0.014), and 0.59 (95% CI, 0.35-0.98, p = 0.05). Therefore, metformin and AGIs might be more suitable for patients with COVID-19 and T2DM while insulin might be used with caution.

CD151 Maintains Endolysosomal Protein Quality to Inhibit Vascular Inflammation.

BACKGROUND: Tetraspanin CD151 is highly expressed in endothelia and reinforces cell adhesion, but its role in vascular inflammation remains largely unknown. METHODS: In vitro molecular and cellular biological analyses on genetically modified endothelial cells, in vivo vascular biological analyses on genetically engineered mouse models, and in silico systems biology and bioinformatics analyses on CD151-related events. RESULTS: Endothelial ablation of Cd151 leads to pulmonary and cardiac inflammation, severe sepsis, and perilous COVID-19, and endothelial CD151 becomes downregulated in inflammation. Mechanistically, CD151 restrains endothelial release of proinflammatory molecules for less leukocyte infiltration. At the subcellular level, CD151 determines the integrity of multivesicular bodies/lysosomes and confines the production of exosomes that carry cytokines such as ANGPT2 (angiopoietin-2) and proteases such as cathepsin-D. At the molecular level, CD151 docks VCP (valosin-containing protein)/p97, which controls protein quality via mediating deubiquitination for proteolytic degradation, onto endolysosomes to facilitate VCP/p97 function. At the endolysosome membrane, CD151 links VCP/p97 to (1) IFITM3 (interferon-induced transmembrane protein 3), which regulates multivesicular body functions, to restrain IFITM3-mediated exosomal sorting, and (2) V-ATPase, which dictates endolysosome pH, to support functional assembly of V-ATPase. CONCLUSIONS: Distinct from its canonical function in strengthening cell adhesion at cell surface, CD151 maintains endolysosome function by sustaining VCP/p97-mediated protein unfolding and turnover. By supporting protein quality control and protein degradation, CD151 prevents proteins from (1) buildup in endolysosomes and (2) discharge through exosomes, to limit vascular inflammation. Also, our study conceptualizes that balance between degradation and discharge of proteins in endothelial cells determines vascular information. Thus, the IFITM3/V-ATPase-tetraspanin-VCP/p97 complexes on endolysosome, as a protein quality control and inflammation-inhibitory machinery, could be beneficial for therapeutic intervention against vascular inflammation.

Application of a circular-shaped pulsed field ablation catheter with magnetic sensors for pulmonary vein isolation: a multi-centre clinical study report.

AIMS: A few studies have reported the effect and safety of pulsed field ablation (PFA) catheters for ablating atrial fibrillation (AF), which were mainly based on basket-shaped or flower-shaped designs. However, the clinical application of a circular-shaped multi-electrode catheter with magnetic sensors is very limited. To study the efficacy and safety of a PFA system in patients with paroxysmal AF using a circular-shaped multi-electrode catheter equipped with magnetic sensors for pulmonary vein isolation (PVI). METHODS AND RESULTS: A novel proprietary bipolar PFA system was used for PVI, which utilized a circular-shaped multi-electrode catheter with magnetic sensors and allowed for three-dimensional model reconstruction, mapping, and ablation in one map. To evaluate the efficacy, efficiency, and safety of this PFA system, a prospective, multi-centre, single-armed, pre-market clinical study was performed. From July 2021 to December 2022, 151 patients with paroxysmal AF were included and underwent PVI. The study examined procedure time, immediate success rate, procedural success rate at 12 months, and relevant complications. In all 151 patients, all the pulmonary veins were acutely isolated using the studied system. Pulsed field ablation delivery was 78.4 ± 41.8 times and 31.3 ± 16.7 ms per patient. Skin-to-skin procedure time was 74.2 ± 29.8 min, and fluoroscopy time was 13.1 ± 7.6 min. The initial 11 (7.2%) cases underwent procedures with deep sedation anaesthesia, and the following cases underwent local anaesthesia. In the initial 11 cases, 4 cases (36.4%) presented transient vagal responses, and the rest were all successfully preventatively treated with atropine injection and rapid fluid infusion. No severe complications were found during or after the procedure. During follow-up, 3 cases experienced atrial flutter, and 11 cases had AF recurrence. The estimated 12-month Kaplan-Meier of freedom from arrhythmia was 88.4%. CONCLUSION: The PFA system, comprised of a circular PFA catheter with magnetic sensors, could rapidly achieve PVI under three-dimensional guidance and demonstrated excellent safety with comparable effects.

The involvement of soluble epoxide hydrolase in the development of cardiovascular diseases through epoxyeicosatrienoic acids.

Arachidonic acid (AA) has three main metabolic pathways: the cycloxygenases (COXs) pathway, the lipoxygenases (LOXs) pathway, and the cytochrome P450s (CYPs) pathway. AA produces epoxyeicosatrienoic acids (EETs) through the CYPs pathway. EETs are very unstable in vivo and can be degraded in seconds to minutes. EETs have multiple degradation pathways, but are mainly degraded in the presence of soluble epoxide hydrolase (sEH). sEH is an enzyme of bifunctional nature, and current research focuses on the activity of its C-terminal epoxide hydrolase (sEH-H), which hydrolyzes the EETs to the corresponding inactive or low activity diol. Previous studies have reported that EETs have cardiovascular protective effects, and the activity of sEH-H plays a role by degrading EETs and inhibiting their protective effects. The activity of sEH-H plays a different role in different cells, such as inhibiting endothelial cell proliferation and migration, but promoting vascular smooth muscle cell proliferation and migration. Therefore, it is of interest whether the activity of sEH-H is involved in the initiation and progression of cardiovascular diseases by affecting the function of different cells through EETs.

Nuclear AGO2 promotes myocardial remodeling by activating ANKRD1 transcription in failing hearts.

Heart failure (HF) is manifested by transcriptional and posttranscriptional reprogramming of critical genes. Multiple studies have revealed that microRNAs could translocate into subcellular organelles such as the nucleus to modify gene expression. However, the functional property of subcellular Argonaute2 (AGO2), the core member of the microRNA machinery, has remained elusive in HF. AGO2 was found to be localized in both the cytoplasm and nucleus of cardiomyocytes, and robustly increased in the failing hearts of patients and animal models. We demonstrated that nuclear AGO2 rather than cytosolic AGO2 overexpression by recombinant adeno-associated virus (serotype 9) with cardiomyocyte-specific troponin T promoter exacerbated the cardiac dysfunction in transverse aortic constriction (TAC)-operated mice. Mechanistically, nuclear AGO2 activates the transcription of ANKRD1, encoding ankyrin repeat domain-containing protein 1 (ANKRD1), which also has a dual function in the cytoplasm as part of the I-band of the sarcomere and in the nucleus as a transcriptional cofactor. Overexpression of nuclear ANKRD1 recaptured some key features of cardiac remodeling by inducing pathological MYH7 activation, whereas cytosolic ANKRD1 seemed cardioprotective. For clinical practice, we found ivermectin, an antiparasite drug, and ANPep, an ANKRD1 nuclear location signal mimetic peptide, were able to prevent ANKRD1 nuclear import, resulting in the improvement of cardiac performance in TAC-induced HF.

Artificial-intelligence-based risk prediction and mechanism discovery for atrial fibrillation using heart beat-to-beat intervals.

BACKGROUND: Early diagnosis of atrial fibrillation (AF) is important for preventing stroke and other complications. Predicting AF risk in advance can improve early diagnostic efficiency. Deep learning has been used for disease risk prediction; however, it lacks adherence to evidence-based medicine standards. Identifying the underlying mechanisms behind disease risk prediction is important and required. METHODS: We developed an explainable deep learning model called HBBI-AI to predict AF risk using only heart beat-to-beat intervals (HBBIs) during sinus rhythm. We proposed a possible AF mechanism based on the model's explainability and verified this conjecture using confirmed AF risk factors while also examining new AF risk factors. Finally, we investigated the changes in clinicians' ability to predict AF risk using only HBBIs before and after learning the model's explainability. FINDINGS: HBBI-AI consistently performed well across large in-house and external public datasets. HBBIs with large changes or extreme stability were critical predictors for increased AF risk, and the underlying cause was autonomic imbalance. We verified various AF risk factors and discovered that autonomic imbalance was associated with all these factors. Finally, cardiologists effectively understood and learned from these findings to improve their abilities in AF risk prediction. CONCLUSIONS: HBBI-AI effectively predicted AF risk using only HBBI information through evaluating autonomic imbalance. Autonomic imbalance may play an important role in many risk factors of AF rather than in a limited number of risk factors. FUNDING: This study was supported in part by the National Key R&D Program and the National Natural Science Foundation of China.

NT-proBNP ratio is a potential predictor for COVID-19 outcomes in adult Chinese patients: a retrospective study.

Despite the progressive decline in the virulence of the novel coronavirus, there has been no corresponding reduction in its associated hospital mortality. Our aim was to redefine an accurate predictor of mortality risk in COVID-19 patients, enabling effective management and resource allocation. We conducted a retrospective analysis of 2917 adult Chinese patients diagnosed with COVID-19 who were admitted to our hospital during two waves of epidemics, involving the Beta and Omicron variants. Upon admission, NT-proBNP levels were measured, and we collected demographic, clinical, and laboratory data. We introduced a new concept called the NT-proBNP ratio, which measures the NT-proBNP level relative to age-specific maximum normal values. The primary outcome was all-cause in-hospital mortality. Our analysis revealed a higher in-hospital mortality rate in 2022, as shown by the Kaplan-Meier Survival Curve. To assess the predictive value of the NT-proBNP ratio, we employed the time-dependent receiver operating characteristic (ROC) curve. Notably, the NT-proBNP ratio emerged as the strongest predictor of mortality in adult Chinese hospitalized COVID-19 patients (area under the curve, AUC = 0.826; adjusted hazard ratio [HR], 3.959; 95% confidence interval [CI] 3.001-5.221; P < 0.001). This finding consistently held true for both the 2020 and 2022 subgroups. The NT-proBNP ratio demonstrates potential predictive capability compared to several established risk factors, including NT-proBNP, hsCRP, and neutrophil-to-lymphocyte ratio, when it comes to forecasting in-hospital mortality among adult Chinese patients with COVID-19.Trial registration Clinical Trial Registration: www.clinicaltrials.gov NCT05615792.

Chinese Society of Cardiology guidelines on the diagnosis and treatment of adult fulminant myocarditis.

Fulminant myocarditis is an acute diffuse inflammatory disease of myocardium. It is characterized by acute onset, rapid progress and high risk of death. Its pathogenesis involves excessive immune activation of the innate immune system and formation of inflammatory storm. According to China's practical experience, the adoption of the "life support-based comprehensive treatment regimen" (with mechanical circulation support and immunomodulation therapy as the core) can significantly improve the survival rate and long-term prognosis. Special emphasis is placed on very early identification,very early diagnosis,very early prediction and very early treatment.

The Translation, Culture-Adaptation and Psychometric Evaluation of the Cardiac Rehabilitation Barriers Scale Among Chinese Older Population.

Purpose: This study aimed to translate and cross-culturally adapt the cardiac rehabilitation barriers scale to the Chinese, and examine its reliability and validity among the older population. Methods: An approach comprising translation, cultural adaptation, reliability, and validity examination in the Chinese version was conducted in two hospitals in Jilin, China. The t-tests were used to compare the sex differences between each item. Participants included Chinese individuals >60 who were eligible for the cardiac rehabilitation program. Results: In total, 325 participants completed the questionnaire with an average age of 61.23 ± 9.68 years. The item-total correlations were 0.432 to 0.678. Factor analysis of CRBS-C (Kaiser Meyer Olkin = 0.867, Bartlett's test p = 0.000) revealed four factors: logistical factors, comorbidities/functional status, perceived need/healthcare factors, and work/time conflict. The confirmatory factor analysis (CFA) indicated a good model fit (χ2/df = 1.84, RMSEA = 0.051, CFI = 0.953, TLI = 0.945, SRMR=0.046). Cronbach's alpha was 0.88 for the scale, ranging from 0.801 to 0.88 for each item, which indicates the internal reliability was acceptable. Conclusion: The Chinese version of the CRRS has acceptable reliability and validity in the Chinese elderly population.

LncRNA CHKB-DT Downregulation Enhances Dilated Cardiomyopathy Through ALDH2.

BACKGROUND: Human cardiac long noncoding RNA (lncRNA) profiles in patients with dilated cardiomyopathy (DCM) were previously analyzed, and the long noncoding RNA CHKB (choline kinase beta) divergent transcript (CHKB-DT) levels were found to be mostly downregulated in the heart. In this study, the function of CHKB-DT in DCM was determined. METHODS: Long noncoding RNA expression levels in the human heart tissues were measured via quantitative reverse transcription-polymerase chain reaction and in situ hybridization assays. A CHKB-DT heterozygous or homozygous knockout mouse model was generated using the clustered regularly interspaced palindromic repeat (CRISPR)/CRISPR-associated protein 9 system, and the adeno-associated virus with a cardiac-specific promoter was used to deliver the RNA in vivo. Sarcomere shortening was performed to assess the primary cardiomyocyte contractility. The Seahorse XF cell mitochondrial stress test was performed to determine the energy metabolism and ATP production. Furthermore, the underlying mechanisms were explored using quantitative proteomics, ribosome profiling, RNA antisense purification assays, mass spectrometry, RNA pull-down, luciferase assay, RNA-fluorescence in situ hybridization, and Western blotting. RESULTS: CHKB-DT levels were remarkably decreased in patients with DCM and mice with transverse aortic constriction-induced heart failure. Heterozygous knockout of CHKB-DT in cardiomyocytes caused cardiac dilation and dysfunction and reduced the contractility of primary cardiomyocytes. Moreover, CHKB-DT heterozygous knockout impaired mitochondrial function and decreased ATP production as well as cardiac energy metabolism. Mechanistically, ALDH2 (aldehyde dehydrogenase 2) was a direct target of CHKB-DT. CHKB-DT physically interacted with the mRNA of ALDH2 and fused in sarcoma (FUS) through the GGUG motif. CHKB-DT knockdown aggravated ALDH2 mRNA degradation and 4-HNE (4-hydroxy-2-nonenal) production, whereas overexpression of CHKB-DT reversed these molecular changes. Furthermore, restoring ALDH2 expression in CHKB-DT+/- mice alleviated cardiac dilation and dysfunction. CONCLUSIONS: CHKB-DT is significantly downregulated in DCM. CHKB-DT acts as an energy metabolism-associated long noncoding RNA and represents a promising therapeutic target against DCM.

Gut microbiota-dependent phenylacetylglutamine in cardiovascular disease: current knowledge and new insights.

Phenylacetylglutamine (PAGln) is an amino acid derivate that comes from the amino acid phenylalanine. There are increasing studies showing that the level of PAGln is associated with the risk of different cardiovascular diseases. In this review, we discussed the metabolic pathway of PAGln production and the quantitative measurement methods of PAGln. We summarized the epidemiological evidence to show the role of PAGln in diagnostic and prognostic value in several cardiovascular diseases, such as heart failure, coronary heart disease/atherosclerosis, and cardiac arrhythmia. The underlying mechanism of PAGln is now considered to be related to the thrombotic potential of platelets via adrenergic receptors. Besides, other possible mechanisms such as inflammatory response and oxidative stress could also be induced by PAGln. Moreover, since PAGln is produced across different organs including the intestine, liver, and kidney, the cross-talk among multiple organs focused on the function of this uremic toxic metabolite. Finally, the prognostic value of PAGln compared to the classical biomarker was discussed and we also highlighted important gaps in knowledge and areas requiring future investigation of PAGln in cardiovascular diseases.

Molecular recognition and activation of the prostacyclin receptor by anti-pulmonary arterial hypertension drugs.

The prostacyclin (PGI2) receptor (IP) is a Gs-coupled receptor associated with blood pressure regulation, allergy, and inflammatory response. It is a main therapeutic target for pulmonary arterial hypertension (PAH) and several other diseases. Here we report cryo-electron microscopy (cryo-EM) structures of the human IP-Gs complex bound with two anti-PAH drugs, treprostinil and MRE-269 (active form of selexipag), at global resolutions of 2.56 and 2.41 angstrom, respectively. These structures revealed distinct features governing IP ligand binding, receptor activation, and G protein coupling. Moreover, comparison of the activated IP structures uncovered the mechanism and key residues that determine the superior selectivity of MRE-269 over treprostinil. Combined with molecular docking and functional studies, our structures provide insight into agonist selectivity, ligand recognition, receptor activation, and G protein coupling. Our results provide a structural template for further improving IP-targeting drugs to reduce off-target activation of prostanoid receptors and adverse effects.

LncRNA MIR217HG aggravates pressure-overload induced cardiac remodeling by activating miR-138/THBS1 pathway.

AIM: Cardiac hypertrophy and fibrosis are associated with cardiac remodeling and heart failure. We have previously shown that miRNA-217, embedded within the third intron of MIR217HG, aggravates pressure overload-induced cardiac hypertrophy by targeting phosphatase and tensin homolog. However, whether the MIR217HG transcript itself plays a role in cardiac remodeling remains unknown. METHODS: Real-time PCR assays and RNA in situ hybridization were performed to detect MIR217HG expression. Lentiviruses and adeno-associated viruses with a cardiac-specific promoter (cTnT) were used to control MIR217HG expression in vitro and in vivo. Transverse aortic constriction (TAC) surgery was performed to develop cardiac remodeling models. Cardiac structure and function were analyzed using echocardiography and invasive pressure-volume analysis. KEY FINDINGS: MIR217HG expression was increased in patients with heart failure. MIR217HG overexpression aggravated pressure-overload-induced myocyte hypertrophy and fibrosis both in vivo and in vitro, whereas MIR217HG knockdown reversed these phenotypes. Mechanistically, MIR217HG increased THBS1 expression by sponging miR-138. MiR-138 recognized the 3'UTR of THBS1 and repressed THBS1 expression in the absence of MIR217HG. Silencing THBS1 expression reversed MIR217HG-induced cardiac hypertrophy and remodeling. CONCLUSION: MIR217HG acts as a potent inducer of cardiac remodeling that may contribute to heart failure by activating the miR-138/THBS1 pathway.

Ganglioside GM3 Protects Against Abdominal Aortic Aneurysm by Suppressing Ferroptosis.

BACKGROUND: Abdominal aortic aneurysm (AAA) is a potentially life-threatening vascular condition, but approved medical therapies to prevent AAA progression and rupture are currently lacking. Sphingolipid metabolism disorders are associated with the occurrence and development of AAA. It has been discovered that ganglioside GM3, a sialic acid-containing type of glycosphingolipid, plays a protective role in atherosclerosis, which is an important risk factor for AAA; however, the potential contribution of GM3 to AAA development has not been investigated. METHODS: We performed a metabolomics study to evaluated GM3 level in plasma of human patients with AAA. We profiled GM3 synthase (ST3GAL5) expression in the mouse model of aneurysm and human AAA tissues through Western blotting and immunofluorescence staining. RNA sequencing, affinity purification and mass spectrometry, proteomic analysis, surface plasmon resonance analysis, and functional studies were used to dissect the molecular mechanism of GM3-regulating ferroptosis. We conditionally deleted and overexpressed St3gal5 in smooth muscle cells (SMCs) in vivo to investigate its role in AAA. RESULTS: We found significantly reduced plasma levels of GM3 in human patients with AAA. GM3 content and ST3GAL5 expression were decreased in abdominal aortic vascular SMCs in patients with AAA and an AAA mouse model. RNA sequencing analysis showed that ST3GAL5 silencing in human aortic SMCs induced ferroptosis. We showed that GM3 interacted directly with the extracellular domain of TFR1 (transferrin receptor 1), a cell membrane protein critical for cellular iron uptake, and disrupted its interaction with holo-transferrin. SMC-specific St3gal5 knockout exacerbated iron accumulation at lesion sites and significantly promoted AAA development in mice, whereas GM3 supplementation suppressed lipid peroxidation, reduced iron deposition in aortic vascular SMCs, and markedly decreased AAA incidence. CONCLUSIONS: Together, these results suggest that GM3 dysregulation promotes ferroptosis of vascular SMCs in AAA. Furthermore, GM3 may constitute a new therapeutic target for AAA.