Ceramide-1-phosphate alleviates high-altitude pulmonary edema by stabilizing circadian ARNTL-mediated mitochondrial dynamics.

INTRODUCTION: High-altitude pulmonary edema (HAPE) is a severe and potentially fatal condition with limited treatment options. Although ceramide kinase (CERK)-derived ceramide-1-phosphate (C1P) has been demonstrated to offer protection against various pulmonary diseases, its effects on HAPE remain unclear. OBJECTIVES: Our study aimed to investigate the potential role of CERK-derived C1P in the development of HAPE and to reveal the molecular mechanisms underlying its protective effects. We hypothesized that CERK-derived C1P could protect against HAPE by stabilizing circadian rhythms and maintaining mitochondrial dynamics. METHODS: To test our hypothesis, we used CERK-knockout mice and established HAPE mouse models using a FLYDWC50-1C hypobaric hypoxic cabin. We utilized a range of methods, including lipidomics, transcriptomics, immunofluorescence, Western blotting, and transmission electron microscopy, to identify the mechanisms of regulation. RESULTS: Our findings demonstrated that CERK-derived C1P played a protective role against HAPE. Inhibition of CERK exacerbated HAPE induced by the hypobaric hypoxic environment. Specifically, we identified a novel mechanism in which CERK inhibition induced aryl hydrocarbon receptor nuclear translocator-like (ARNTL) autophagic degradation, inducing the circadian rhythm and triggering mitochondrial damage by controlling the expression of proteins required for mitochondrial fission and fusion. The decreased ARNTL caused by CERK inhibition impaired mitochondrial dynamics, induced oxidative stress damage, and resulted in defects in mitophagy, particularly under hypoxia. Exogenous C1P prevented ARNTL degradation, alleviated mitochondrial damage, neutralized oxidative stress induced by CERK inhibition, and ultimately relieved HAPE. CONCLUSIONS: This study provides evidence for the protective effect of C1P against HAPE, specifically, through stabilizing circadian rhythms and maintaining mitochondrial dynamics. Exogenous C1P therapy may be a promising strategy for treating HAPE. Our findings also highlight the importance of the circadian rhythm and mitochondrial dynamics in the pathogenesis of HAPE, suggesting that targeting these pathways may be a potential therapeutic approach for this condition.

Predictive validation of existing bleeding and thromboembolic scores in elderly patients with comorbid atrial fibrillation and acute coronary syndrome.

BACKGROUND: The validation of various risk scores in elderly patients with comorbid atrial fibrillation (AF) and acute coronary syndrome (ACS) has not been reported. The present study compared the predictive performance of existing risk scores in these patients. METHODS: A total of 1252 elderly patients with AF and ACS comorbidities (≥ 65 years old) were consecutively enrolled from January 2015 to December 2019. All patients were followed up for one year. The predictive performance of risk scores in predicting bleeding and thromboembolic events was calculated and compared. RESULTS: During the 1-year follow-up, 183 (14.6%) patients had thromboembolic events, 198 (15.8%) patients had BARC class ≥ 2 bleeding events, and 61 (4.9%) patients had BARC class ≥ 3 bleeding events. For the BARC class ≥ 3 bleeding events, discrimination of the existing risk scores was low to moderate, PRECISE-DAPT (C-statistic: 0.638, 95% CI: 0.611-0.665), ATRIA (C-statistic: 0.615, 95% CI: 0.587-0.642), PARIS-MB (C-statistic: 0.612, 95% CI: 0.584-0.639), HAS-BLED (C-statistic: 0.597, 95% CI: 0.569-0.624) and CRUSADE (C-statistic: 0.595, 95% CI: 0.567-0.622). However, the calibration was good. PRECISE-DAPT showed a higher integrated discrimination improvement (IDI) than PARIS-MB, HAS-BLED, ATRIA, and CRUSADE (P < 0.05) and the best decision curve analysis (DCA). For thromboembolic events, the discrimination of GRACE (C-statistic: 0.636, 95% CI: 0.608-0.662) was higher than CHA2DS2-VASc (C-statistic: 0.612, 95% CI: 0.584-0.639), OPT-CAD (C-statistic: 0.602, 95% CI: 0.574-0.629) and PARIS-CTE (C-statistic: 0.595, 95% CI: 0.567-0.622). The calibration was good. Compared to OPT-CAD and PARIS-CTE, the IDI of the GRACE score slightly improved (P < 0.05). However, NRI analysis showed no significant difference. DCA showed that the clinical practicability of thromboembolic risk scores was similar. CONCLUSIONS: The discrimination and calibration of existing risk scores in predicting 1-year thromboembolic and bleeding events were unsatisfactory in elderly patients with comorbid AF and ACS. PRECISE-DAPT showed higher IDI and DCA than other risk scores in predicting BARC class ≥ 3 bleeding events. The GRACE score showed a slight advantage in predicting thrombotic events.

Low-dose of caffeine alleviates high altitude pulmonary edema via regulating mitochondrial quality control process in AT1 cells.

Backgrounds: High-altitude pulmonary edema (HAPE) is a life-threatening disease without effective drugs. Caffeine is a small molecule compound with antioxidant biological activity used to treat respiratory distress syndrome. However, it is unclear whether caffeine plays a role in alleviating HAPE. Methods: We combined a series of biological experiments and label-free quantitative proteomics analysis to detect the effect of caffeine on treating HAPE and explore its mechanism in vivo and in vitro. Results: Dry and wet weight ratio and HE staining of pulmonary tissues showed that the HAPE model was constructed successfully, and caffeine relieved pulmonary edema. The proteomic results of mice lungs indicated that regulating mitochondria might be the mechanism by which caffeine reduced HAPE. We found that caffeine blocked the reduction of ATP production and oxygen consumption rate, decreased ROS accumulation, and stabilized mitochondrial membrane potential to protect AT1 cells from oxidative stress damage under hypoxia. Caffeine promoted the PINK1/parkin-dependent mitophagy and enhanced mitochondrial fission to maintain the mitochondria quality control process. Conclusion: Low-dose of caffeine alleviated HAPE by promoting PINK1/parkin-dependent mitophagy and mitochondrial fission to control the mitochondria quality. Therefore, caffeine could be a potential treatment for HAPE.

MiR-130a-3p regulates FUNDC1-mediated mitophagy by targeting GJA1 in myocardial ischemia/reperfusion injury.

Understanding the complex pathogenesis in myocardial ischemia/reperfusion (I/R) injury (IRI) is an urgent problem in clinical trials. Increasing pieces of evidence have suggested that miRNAs are involved in the occurrence and development of heart diseases by regulating mitochondria-related gene expression. Mitochondria have been acknowledged as the key triggers of cardiac I/R injury. However, the potential impact of miR-130a on mitochondria remains unclear in myocardial IRI. Exploring the regulatory mechanism of miR-130a on mitochondria may provide a new target for IRI therapy. In the present study, we found that miR-130a significantly increased in acute myocardial infarction (AMI) patients and myocardial I/R rats. MiR-130a could downregulate the viability of cardiomyocytes and the knockdown of miR-130a could protect the viability of cardiomyocytes under hypoxia-reoxygenation (HR). Over-expression of miR-130a resulted in mitochondrial dysfunction. It was evidenced by decreases in mitochondrial ATP production, mitochondrial membrane potential (MMP), and an increase in reactive oxygen species (ROS) production. However, suppression of miR-130a could protect against mitochondrial damage, show elevation of mitochondrial ATP production rate and MMP, and reduce ROS production. We further explored the effect of miR-130a on the mitochondrial quality control (QMC) system by determining mitochondrial-protein-specific proteases and analyzed mitochondrial morphology by fluorescence imaging and electron microscopy, respectively. It was noted that miR-130a could suppress mitochondrial fusion and FUNDC1-mediated mitophagy to accelerate myocardial IRI. Moreover, we investigated the potential miR-130a targeted mitochondria-related genes to understand the regulatory mechanism of miR-130a in the setting of myocardial IRI. It was revealed that miR-130a targeted GJA1, and GJA1 rescued IRI by enhancing ATP production rate and oxidative phosphorylation, meanwhile protecting cell viability, MMP, and activating mitophagy. In addition, the knockdown of miR-130a significantly activated FUNDC1-mediated mitophagy, while the knockdown of GJA1 reversed the relevant response. Collectively, our findings suggest that miR-130a regulates FUNDC1-mediated mitophagy by targeting GJA1 in myocardial IRI.

Transcriptional landscape in rat intestines under hypobaric hypoxia.

Oxygen metabolism is closely related to the intestinal homeostasis environment, and the occurrence of many intestinal diseases is as a result of the destruction of oxygen gradients. The hypobaric hypoxic environment of the plateau can cause dysfunction of the intestine for humans, such as inflammation. The compensatory response of the small intestine cells to the harsh environment definitely changes their gene expression. How the small intestine cells response the hypobaric hypoxic environment is still unclear. We studied the rat small intestine under hypobaric hypoxic conditions to explore the transcriptional changes in rats under acute/chronic hypobaric hypoxic conditions. We randomly divided rats into three groups: normal control group (S), acute hypobaric hypoxia group, exposing to hypobaric hypoxic condition for 2 weeks (W2S) and chronic hypobaric hypoxia group, exposing to hypobaric hypoxic condition for 4 weeks (W4S). The RNA sequencing was performed on the small intestine tissues of the three groups of rats. The results of principal component analysis showed that the W4S and W2S groups were quite different from the control group. We identified a total of 636 differentially expressed genes, such as ATP binding cassette, Ace2 and Fabp. KEGG pathway analysis identified several metabolic and digestive pathways, such as PPAR signaling pathway, glycerolipid metabolism, fat metabolism, mineral absorption and vitamin metabolism. Cogena analysis found that up-regulation of digestive and metabolic functions began from the second week of high altitude exposure. Our study highlights the critical role of metabolic and digestive pathways of the intestine in response to the hypobaric hypoxic environment, provides new aspects for the molecular effects of hypobaric hypoxic environment on intestine, and raises further questions about between the lipid metabolism disorders and inflammation.

Protective Effect of Mitochondrial ND2 C5178A Gene Mutation on Cell and Mitochondrial Functions.

BACKGROUND: Mitochondrial NADH dehydrogenase subunit 2 (MT-ND2) m. 5178C>A gene mutation has protective effects against various diseases, but the molecular mechanism is still unclear. In previous study, we found a heteroplasmy level of MT-ND2 m. 5178C>A mutation in normotensive controls. Peripheral blood samples were obtained from essential hypertension individuals carrying the mutation and healthy controls without gene mutation to establish immortalized lymphocyte lines. To investigate the effect of the MT-ND2 m. 5178C>A gene mutation, comparative analyses of the two group cell lines were performed, including measurements of cell proliferation, viability, ATP synthesis, mitochondrial oxidative stress, and oxidative phosphorylation. RESULTS: The cell proliferation rate and viability of the MT-ND2 m. 5178C>A mutant lymphocyte line were higher than those of the control group. Mitochondrial functions of the MT-ND2 m. 5178C>A mutant lymphocyte were increased, including increased ATP synthesis, decreased ROS production, increased mitochondrial membrane potential and Bcl-2 gene transcription and protein translation, decreased Caspase 3/7 activity, and decreased early apoptosis and late apoptosis. The oxygen consumption rate (OCR) of the mutant lymphocyte line was higher than that of the control group, including basal OCR, ATP-linked OCR, maximal OCR, proton leak OCR, and reserve OCR, and there was no significant difference in nonmitochondrial OCR. The activity of Mitochondrial Complex I of the mutant group was increased than that of the control group. CONCLUSIONS: The MT-ND2 m. 5178C>A mutation is a protective mutation that may be related to improvement of mitochondrial functions and decrease in apoptosis.

A study of the sequential treatment of acute heart failure with sacubitril/valsartan by recombinant human brain natriuretic peptide: A randomized controlled trial.

ABSTRACT: This study aimed to investigate the effects of the basic treatment for heart failure and sequential treatment with rh-brain natriuretic peptide (rhBNP) alone or the combination of rhBNP and sacubitril/valsartan. Cardiac structure, pulmonary artery pressure, inflammation and oxidative stress in patients with acute heart failure were evaluated.Three hundred patients with acute heart failure were included. According to the random number table method, the patients were divided into 3 groups of 100 patients per group: the standard treatment group (treated with an angiotensin-converting enzyme inhibitor, ß receptor blocker, and corticosteroid antagonist), rhBNP group (basic treatment combined with rhBNP) and sequential treatment group (basic treatment for heart failure combined with rhBNP followed by sacubitril/valsartan). The changes in NT-probrain natriuretic peptide (BNP) levels, cardiac troponin T (cTnT) levels, cardiac structure, pulmonary artery pressure, and the levels inflammatory factors and oxidative stress factors were compared among the 3 groups at 1, 4, 12, and 36 weeks after treatment.The sequential treatment group displayed superior outcomes than the standard treatment group and the rhBNP group in terms of left atrium diameter, left ventricular end diastolic volume, left ventricular ejection fraction, pulmonary artery pressure, NT-proBNP levels, and cTnT levels, which respond to damage to the heart structure and myocardium. This result may be related to the decreased levels of inflammatory factors and the correction of oxidative stress imbalance.Sacubitril/valsartan significantly reduce the serum levels of inflammatory factors in patients with acute heart failure while decreasing the levels of oxidizing factors and increasing the levels of antioxidant factors. These changes may be one of the explanations for the better cardiac structure and better pulmonary artery pressure observed in the sequential treatment group.

Chlorogenic acid prevents acute myocardial infarction in rats by reducing inflammatory damage and oxidative stress.

Recent studies have suggested that the prevention of myocardial infarction (MI) through diet is very important and that the intake of polyphenol-rich foods can improve cardiovascular health. In this study, adult male SD rats were randomly divided into 2 groups. The chlorogenic acid (CGA) group (n = 18) was administered 100 mg/kg/day CGA by gavage, and the control (CON) group (n = 18) was given the equivalent volume of water for 4 weeks. A model of MI was established by ligating the left anterior descending (LAD) coronary artery, which was monitored by an electrocardiogram (ECG). Blood samples were analyzed by enzyme-linked immunosorbent assays and biochemical experiments 24 h after the operation. In addition, histopathological analysis was performed to assess the size and severity of the infarct area. The administration of CGA before MI minimized weight gain and was associated with decreased postoperative mortality. CGA moderated the coronary artery ligation-induced changes observed by ECG and decreased the plasma levels of the myocardial markers. In the histopathological analysis, CGA notably reduced infarct size and decreased myocardial injury and fibrosis. Furthermore, CGA significantly reduced the levels of pro-inflammatory factors, and this reduction was accompanied by an upregulation of anti-inflammatory cytokines and an increase in antioxidant enzyme activities. This study indicated that CGA improved the survival rate after MI and demonstrated that CGA had a protective effect on MI by reducing the inflammatory response and exerting antioxidant activity.

Photoactive Oligo(p-phenylene vinylene) Material for Functional Regulation of Induced Pluripotent Stem Cells.

In recent years, rapid development of induced pluripotent stem cell (iPSC) technology has provided good technical support for the study of human cardiovascular disease (CVD). In this work, a mimetic cell membrane and drug carrier OPFL system containing photoactive oligo(p-phenylene vinylene) functionalized with phospholipid units (OPV-lipid) was prepared for functional regulation of iPSC-derived cardiomyocytes. OPFL bound to the cell membrane of iPSC-derived human cardiomyocytes and significantly enhanced delivery of cyclosporin A (CsA) into these cells, which promoted the regulation of mitochondrial calcium levels and membrane potential by CsA. This led to the protection of the mitochondrial structure and function, thus reducing apoptosis of iPSC-derived cardiomyocytes and achieving the effect of treating CVD. OPFL not only acts as a fluorescent probe for cell imaging and visualization of the drug delivery process but also provides a tool to deliver lipid-insoluble drugs throughout the cell membrane. Benefiting from good biocompatibility, facile operation, and a visible and controllable cell uptake process, OPFL has good potential to be a powerful tool in future basic and clinical research applications involving iPSCs.

Evaluation of homocysteine in the diagnosis and prognosis of coronary slow flow syndrome.

Aim: To identify the exact molecular markers related to coronary slow flow syndrome (CSFS) and its prognosis. Patients & methods: Data from 54 patients with CSFS diagnosed by coronary angiography and 101 normal control patients were collected and analyzed. Results: Logistic regression analysis confirmed that homocysteine (Hcy; odds ratio: 1.107; 95% CI: 1.018-1.205; p = 0.018) was associated with CSFS. Receiver-operating characteristic curve analysis identified an Hcy value of 17.1 µmol/l as an effective cut-off point for predicting CSFS. Cox survival analysis showed a relationship between high admission Hcy level (odds ratio: 1.19; 95% CI = 1.05-1.34; p = 0.005) and recurrent angina. Conclusion: Our results showed positive correlations of Hcy with CSFS and cardiac events.

Mitochondrial outer membrane voltage-dependent anion channel is involved in renal dysfunction in a spontaneously hypertensive rat carrying transfer RNA mutations.

Mitochondrial DNA mutations promote hypertensive renal dysfunction, but the molecular mechanism remains unclear. This study compared renal damage between spontaneously hypertensive rats (SHR) and SHR with mitochondrial transfer (t)RNA mutations. To investigate the role of mitochondrial outer membrane voltage-dependent anion channel 1 (VDAC1) in the process of tRNA-promoting mitochondrial dysfunction, we treated HK-2 cells with H2O2, cyclosporine (CsA), or atractylodin (Atr) to observe the association between VDAC1 and mitochondrial function. Intriguingly, the mitochondrial structure of SHR carrying tRNA mutations was obviously disordered, and reactive oxygen species production and VDAC1 and Bax expression and binding were increased, which was associated with marked renal dysfunction. The expression of VDAC1 and Bax was also up-regulated in HK-2 cells by H2O2 treatment. However, CsA and Atr had no significant effect on the expression of VDAC1 and Bax. H2O2 caused mitochondrial membrane potential collapse, while CsA could increase the mitochondrial membrane potential and Atr had the opposite effect. Treatment with H2O2 significantly decreased ATP synthesis, which was improved by intervention with Atr. H2O2 also decreased the maximum oxygen consumption rate, while CsA and Atr had no significant effect. We found that H2O2 promoted the colocalization of VDAC1 and Bax, which was partially inhibited by intervention with CsA or Atr. In conclusion, we found that tRNA mutations promoted hypertensive renal insufficiency. Increased reactive oxygen species was an important associated mechanism, which inhibited mitochondrial function by affecting VDAC1 expression and function.

Kv4.3 Modulates the Distribution of hERG.

This study examines the interaction between hERG and Kv4.3. The functional interaction between hERG and Kv4.3, expressed in a heterologous cell line, was studied using patch clamp techniques, western blot, immunofluorescence, and co-immunoprecipitation. Co-expression of Kv4.3 with hERG increased hERG current density (tail current after a step to +10 mV: 26 ± 3 versus 56 ± 7 pA/pF, p < 0.01). Kv4.3 co-expression also increased the protein expression and promoted the membrane localization of hERG. Western blot showed Kv4.3 increased hERG expression by Hsp70. hERG and Kv4.3 co-localized and co-immunoprecipitated in cultured 293 T cells, indicating physical interactions between hERG and Kv4.3 proteins in vitro. In addition, Hsp70 interacted with hERG and Kv4.3 respectively, and formed complexes with hERG and Kv4.3. The α subunit of Ito Kv4.3 can interact with and modify the localization of the α subunit of IKr hERG, thus providing potentially novel insights into the molecular mechanism of the malignant ventricular arrhythmia in heart failure.

Mitochondrial biogenesis dysfunction and metabolic dysfunction from a novel mitochondrial tRNAMet 4467 C>A mutation in a Han Chinese family with maternally inherited hypertension.

To investigate the relationship between mitochondrial DNA (mtDNA) and hypertension as well as the mechanism involved in mitochondrial metabolic dysfunction. We identified a novel tRNAMet C4467A mutation in a Han Chinese family with hypertension. The maternal members presented with increased glucose, total cholesterol, low-density lipoprotein, and serum sodium as well as decreased potassium compared with non-maternal members (P < 0.05). Segregation analysis showed this mutation was maternally inherited. We analyzed lymphocyte cell lines derived from three maternal and three non-maternal family members. Reactive oxygen species production in the mutant cell lines was 114.5% higher compared with that in controls (P < 0.05) while ATP was 26.4% lower. The mitochondrial membrane potential of the mutated cell lines was 26.2% lower than that in controls (P < 0.05). Oxygen consumption rates were decreased in the mutant cell lines (P < 0.05). The activation of caspase-3/7 was 104.1% higher in the mutant cell lines compared with controls (P < 0.05). The expression of voltage-dependent anion channel (VDAC), Bax and apoptosis-inducing factor (AIF) in the mutant cell lines was higher compared with that in controls, with the increased colocalization of VDAC and Bax. Therefore, this mutation contributes to oxidative stress and mitochondrial biogenesis dysfunction, which may be involved in the pathogenesis of hypertension.

Effects of allocryptopine on outward potassium current and slow delayed rectifier potassium current in rabbit myocardium.

OBJECTIVE: Allocryptopine (ALL) is an effective alkaloid of Corydalis decumbens (Thunb.) Pers. Papaveraceae and has proved to be anti-arrhythmic. The purpose of our study is to investigate the effects of ALL on transmural repolarizing ionic ingredients of outward potassium current (I to) and slow delayed rectifier potassium current (I Ks). METHODS: The monophasic action potential (MAP) technique was used to record the MAP duration of the epicardium (Epi), myocardium (M) and endocardium (Endo) of the rabbit heart and the whole cell patch clamp was used to record I to and I Ks in cardiomyocytes of Epi, M and Endo layers that were isolated from rabbit ventricles. RESULTS: The effects of ALL on MAP of Epi, M and Endo layers were disequilibrium. ALL could effectively reduce the transmural dispersion of repolarization (TDR) in rabbit transmural ventricular wall. ALL decreased the current densities of I to and I Ks in a voltage and concentration dependent way and narrowed the repolarizing differences among three layers. The analysis of gating kinetics showed ALL accelerated the channel activation of I to in M layers and partly inhibit the channel openings of I to in Epi, M and Endo cells. On the other hand, ALL mainly slowed channel deactivation of I Ks channel in Epi and Endo layers without affecting its activation. CONCLUSIONS: Our study gives partially explanation about the mechanisms of transmural inhibition of I to and I Ks channels by ALL in rabbit myocardium. These findings provide novel perspective regarding the anti-arrhythmogenesis application of ALL in clinical settings.

Extending the linker region increases the activity of the Bacillus subtilis cellulase CelI15.

OBJECTIVES: To investigate the effect of the linker region (LR) on the enzymatic activity, stability, and flexibility of Bacillus subtilis cellulase CelI15, six mutants were constructed that contained increasing numbers of the LR. RESULTS: The CelI15 mutant with three copies of the LR (approx. 57 amino acids) showed the highest activity, which was almost 20 % greater than that of wild type CelI15. The stability of the mutant enzymes increased as the copy number of the LR decreased. However, the substrate affinity of the mutant enzymes increased as the LR copy number increased, and the mutant with four copies of the LR exhibited the highest substrate affinity. Additionally, the flexibility of the CelI15 mutants increased as the LR copy number increased from zero to four copies, although it decreased sharply for the mutant with five copies of the LR. CONCLUSION: The activity of CelI15 was increased by increasing the LR copy number, which could be a potential way to improve its enzymatic properties.