Pyruvate kinase M2 sustains cardiac mitochondrial quality surveillance in septic cardiomyopathy by regulating prohibitin 2 abundance via S91 phosphorylation.

The endogenous mitochondrial quality control (MQC) system serves to protect mitochondria against cellular stressors. Although mitochondrial dysfunction contributes to cardiac damage during many pathological conditions, the regulatory signals influencing MQC disruption during septic cardiomyopathy (SC) remain unclear. This study aimed to investigate the involvement of pyruvate kinase M2 (PKM2) and prohibitin 2 (PHB2) interaction followed by MQC impairment in the pathogenesis of SC. We utilized LPS-induced SC models in PKM2 transgenic (PKM2TG) mice, PHB2S91D-knockin mice, and PKM2-overexpressing HL-1 cardiomyocytes. After LPS-induced SC, cardiac PKM2 expression was significantly downregulated in wild-type mice, whereas PKM2 overexpression in vivo sustained heart function, suppressed myocardial inflammation, and attenuated cardiomyocyte death. PKM2 overexpression relieved sepsis-related mitochondrial damage via MQC normalization, evidenced by balanced mitochondrial fission/fusion, activated mitophagy, restored mitochondrial biogenesis, and inhibited mitochondrial unfolded protein response. Docking simulations, co-IP, and domain deletion mutant protein transfection experiments showed that PKM2 phosphorylates PHB2 at Ser91, preventing LPS-mediated PHB2 degradation. Additionally, the A domain of PKM2 and the PHB domain of PHB2 are required for PKM2-PHB2 binding and PHB2 phosphorylation. After LPS exposure, expression of a phosphorylation-defective PHB2S91A mutant negated the protective effects of PKM2 overexpression. Moreover, knockin mice expressing a phosphorylation-mimetic PHB2S91D mutant showed improved heart function, reduced inflammation, and preserved mitochondrial function following sepsis induction. Abundant PKM2 expression is a prerequisite to sustain PKM2-PHB2 interaction which is a key element for preservation of PHB2 phosphorylation and MQC, presenting novel interventive targets for the treatment of septic cardiomyopathy.

Molecular epidemiological and clinical infection characteristics analysis of Ralstonia.

PURPOSE: This study was to clarify the molecular epidemiology and clinical infection characteristics of Ralstonia pickettii and establish sequence typing system. METHODS: 48 nonrepetitive Ralstonia pickettii strains were collected from January 2008 to December 2013 at the Chinese People's Liberation Army General Hospital (PLAGH) and were identified through a specific PCR experiment, 16 S rDNA experiment and VITEK 2 system to compare the identification accuracy. The sequence types of the strains were analyzed by multilocus sequence typing (MLST) method. The antibiotic sensitivity of these strains was determined with disc diffusion tests and broth microdilution method. The clinical data of Ralstonia pickettii infected patients were collected. RESULTS: All of the 48 strains were identified as Ralstonia pickettii by VITEK 2 system. 30 and 34 strains were identified as Ralstonia pickettii by PCR and 16 S rDNA experiment respectively. ST9 was the most sequence types (STs) in these 18 STs of 42 strains. 42 strains were divided into 2 groups (A and B) and 18 genotypes. Ralstonia pickettii was sensitive to some cephalosporins, ß-lactam/ß-lactamase inhibitor, levofloxacin and trimethoprim/sulfamethoxazole. Cough, sputum, shortness of breath and pulmonary rales were the common clinical symptoms of most Ralstonia pickettii infected patients. CONCLUSION: We established a sequence typing system with a relatively fine resolution and the PCR assay is a faster and more sensitive method for clinical identification of Ralstonia pickettii. ST9 is the most common sequence types of Ralstonia pickettii. The most common clinical characteristics of Ralstonia pickettii infected patients were cough, sputum, shortness of breath and pulmonary rales.

DNA-PKcs Phosphorylates Cofilin2 to Induce Endothelial Dysfunction and Microcirculatory Disorder in Endotoxemic Cardiomyopathy.

The presence of endotoxemia is strongly linked to the development of endothelial dysfunction and disruption of myocardial microvascular reactivity. These factors play a crucial role in the progression of endotoxemic cardiomyopathy. Sepsis-related multiorgan damage involves the participation of the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs). However, whether DNA-PKcs contributes to endothelial dysfunction and myocardial microvascular dysfunction during endotoxemia remains unclear. Hence, we conducted experiments in mice subjected to lipopolysaccharide (LPS)-induced endotoxemic cardiomyopathy, as well as assays in primary mouse cardiac microvascular endothelial cells. Results showed that endothelial-cell-specific DNA-PKcs ablation markedly attenuated DNA damage, sustained microvessel perfusion, improved endothelial barrier function, inhibited capillary inflammation, restored endothelium-dependent vasodilation, and improved heart function under endotoxemic conditions. Furthermore, we show that upon LPS stress, DNA-PKcs recognizes a TQ motif in cofilin2 and consequently induces its phosphorylation at Thr25. Phosphorylated cofilin2 shows increased affinity for F-actin and promotes F-actin depolymerization, resulting into disruption of the endothelial barrier integrity, microvascular inflammation, and defective eNOS-dependent vasodilation. Accordingly, cofilin2-knockin mice expressing a phospho-defective (T25A) cofilin2 mutant protein showed improved endothelial integrity and myocardial microvascular function upon induction of endotoxemic cardiomyopathy. These findings highlight a novel mechanism whereby DNA-PKcs mediates cofilin2Thr25 phosphorylation and subsequent F-actin depolymerization to contribute to endotoxemia-related cardiac microvascular dysfunction.

A novel lncRNA DFRV plays a dual function in influenza A virus infection.

Long noncoding RNAs (lncRNAs) have been associated with a variety of biological activities, including immune responses. However, the function of lncRNAs in antiviral innate immune responses are not fully understood. Here, we identified a novel lncRNA, termed dual function regulating influenza virus (DFRV), elevating in a dose- and time-dependent manner during influenza A virus (IAV) infection, which was dependent on the NFκB signaling pathway. Meanwhile, DFRV was spliced into two transcripts post IAV infection, in which DFRV long suppress the viral replication while DFRV short plays the opposite role. Moreover, DFRV regulates IL-1ß and TNF-α via activating several pro-inflammatory signaling cascades, including NFκB, STAT3, PI3K, AKT, ERK1/2 and p38. Besides, DFRV short can inhibit DFRV long expression in a dose-dependent manner. Collectively, our studies reveal that DFRV may act as a potential dual-regulator to preserve innate immune homeostasis in IAV infection.

Molecular Mechanisms of Mitochondrial Quality Control in Ischemic Cardiomyopathy.

Ischemic cardiomyopathy (ICM) is a special type of coronary heart disease or an advanced stage of the disease, which is related to the pathological mechanism of primary dilated cardiomyopathy. Ischemic cardiomyopathy mainly occurs in the long-term myocardial ischemia, resulting in diffuse myocardial fibrosis. This in turn affects the cardiac ejection function, resulting in a significant impact on myocardial systolic and diastolic function, resulting in a decrease in the cardiac ejection fraction. The pathogenesis of ICM is closely related to coronary heart disease. Mainly due to coronary atherosclerosis caused by coronary stenosis or vascular occlusion, causing vascular inflammatory lesions and thrombosis. As the disease progresses, it leads to long-term myocardial ischemia and eventually ICM. The pathological mechanism is mainly related to the mechanisms of inflammation, myocardial hypertrophy, fibrosis and vascular remodeling. Mitochondria are organelles with a double-membrane structure, so the composition of the mitochondrial outer compartment is basically similar to that of the cytoplasm. When ischemia-reperfusion induces a large influx of calcium into the cell, the concentration of calcium ions in the mitochondrial outer compartment also increases. The subsequent opening of the membrane permeability transition pore in the inner mitochondrial membrane and the resulting calcium overload induces the homeostasis of cardiomyocytes and activates the mitochondrial pathway of apoptosis. Mitochondrial Quality Control (MQC), as an important mechanism for regulating mitochondrial function in cardiomyocytes, affects the morphological structure/function and lifespan of mitochondria. In this review, we discuss the role of MQC (including mitophagy, mitochondrial dynamics, and mitochondrial biosynthesis) in the pathogenesis of ICM and provide important evidence for targeting MQC for ICM.

Receptor-Interacting Protein Kinase 3 Suppresses Mitophagy Activation via the Yes-Associated Protein/Transcription Factor EB Pathways in Septic Cardiomyopathy.

Mitophagy, known as the main mechanism of mitochondrial quality control, determines the pathophysiology of septic cardiomyopathy, although the precise regulatory mechanisms remain elusive. Data from the present study suggested that receptor-interacting protein kinase 3 (RIPK3) expression could be enhanced in response to lipopolysaccharide (LPS) challenge. Upregulated RIPK3 expression was accompanied by severe cardiac injury and cardiac dysfunction. Further examination revealed that elevated RIPK3 expression subsequently inhibited the Yes-associated protein (YAP) pathway, which was accompanied by reduced transcription factor EB (TFEB) expression. Inhibition of TFEB would reduce mitophagy, which ultimately induced cardiomyocyte death under LPS challenge. In contrast, loss of RIPK3 induced the YAP/TFEB/mitophagy pathway alleviated the sensitivity of cardiomyocytes to LPS-induced cytotoxicity. Collectively, the RIPK3/YAP/TFEB axis was confirmed to be responsible for the pathogenesis of septic cardiomyopathy by inhibiting mitophagy. These findings have potential significance for the progression of new approaches to the treatment of septic cardiomyopathy.

NR4A1 Promotes LPS-Induced Acute Lung Injury through Inhibition of Opa1-Mediated Mitochondrial Fusion and Activation of PGAM5-Related Necroptosis.

Mitochondrial dysfunction and necroptosis have been perceived as the primary molecular mechanisms underscoring acute lung injury. Meanwhile, nuclear receptor subfamily 4 group A member 1 (NR4A1) is considered a regulator of inflammation-related endothelial injury in lung tissue although the downstream molecular events remain elusive. In this study, we employed NR4A1-/- mice to decipher the role of NR4A1 in the onset and progression of acute lung injury with a focus on mitochondrial damage and necroptosis. Our results demonstrated that NR4A1 was significantly upregulated in lipopolysaccharide- (LPS-) treated lung tissues. Knockout of NR4A1 overtly improved lung tissue morphology, inhibited inflammation, and reduced oxidative stress in LPS-treated lung tissue. A cell signaling study suggested that NR4A1 deletion repressed levels of PGAM5 and attenuated LPS-mediated necroptosis in primary murine alveolar epithelial type II (ATII) cells, the effects of which were mitigated by PGAM5 overexpression. Moreover, LPS-mediated mitochondrial injury including mitochondrial membrane potential collapse and mitochondrial oxidative stress was drastically improved by NR4A1 deletion. Furthermore, NR4A1 deletion preserved mitochondrial homeostasis through activation of Opa1-related mitochondrial fusion. Silencing of Opa1 triggered mitochondrial dysfunction in NR4A1-deleted ATII cells. Taken together, our data identified NR4A1 as a novel regulator of LPS-related acute lung injury through regulation of mitochondrial fusion and necroptosis, indicating therapeutic promises of targeting NR4A1 in the treatment of acute lung injury in clinical practice.

RIPK3 Induces Cardiomyocyte Necroptosis via Inhibition of AMPK-Parkin-Mitophagy in Cardiac Remodelling after Myocardial Infarction.

Receptor-interacting protein 3- (RIPK3-) modulated necroptosis plays a critical role in cardiac remodelling after myocardial infarction (MI). However, the precise regulatory mechanism is not fully elucidated yet. In the present study, we showed that RIPK3 expression was upregulated in myocardial tissue after MI in a mouse model by coronary artery ligation, as well as in the cardiomyocytes following hypoxic injury in vitro. The increase of RIPK3 expression was found to be accompanied by severe cardiac remodelling, cardiac dysfunction, and higher mortality. Elevated RIPK3 expression subsequently abrogated the AMPK pathway that was accompanied by inhibition of Parkin-mediated mitophagy. Loss of mitophagy increased the opening of mitochondrial permeability transition pore (mPTP), which ultimately induced the cardiomyocyte necroptosis. In contrast, genetic ablation of Ripk3 induced the AMPK/Parkin-mitophagy pathway, favouring a prosurvival state that eventually inhibited mPTP opening and induced the necroptosis of cardiomyocytes in the post-MI cardiac remodelling. In conclusion, our results revealed a key mechanism by which necroptosis could be mediated by RIPK3 via the AMPK/Parkin-mitophagy/mPTP opening axis, which provides a potential therapeutic target in the management of heart failure after MI.

SERCA Overexpression Improves Mitochondrial Quality Control and Attenuates Cardiac Microvascular Ischemia-Reperfusion Injury.

Despite significant advances in the treatment of myocardial ischemia-reperfusion (I/R) injury, coronary circulation is a so far neglected target of cardioprotection. In this study, we investigated the molecular mechanisms underlying I/R injury to cardiac microcirculation. Using gene delivery, we analyzed microvascular protective effects of sarcoplasmic/endoplasmic reticulum Ca2+-ATPase (SERCA) on the reperfused heart and examined the role of SERCA in regulating mitochondrial quality control in cardiac microvascular endothelial cells (CMECs). Our data showed that SERCA overexpression attenuates lumen stenosis, inhibits microthrombus formation, reduces inflammation response, and improves endothelium-dependent vascular relaxation. In vitro experiments demonstrated that SERCA overexpression improves endothelial viability, barrier integrity, and cytoskeleton assembly in CMECs. Mitochondrial quality control, including mitochondrial fusion, mitophagy, bioenergetics, and biogenesis, were disrupted by I/R injury but were restored by SERCA overexpression. SERCA overexpression also restored mitochondrial quality control by inhibiting calcium overload, inactivating xanthine oxidase (XO), and reducing intracellular/mitochondrial reactive oxygen species (ROS). Administration of exogenous XO or a calcium channel agonist abolished the protective effects of SERCA overexpression on mitochondrial quality control and offset the beneficial effects of SERCA overexpression after cardiac microvascular I/R injury. These findings indicate that SERCA overexpression may be an effective approach to targeting cardiac microvascular I/R injury by regulating calcium/XO/ROS signaling and preserving mitochondrial quality control.

Doença Arterial Coronariana Anatômica Associada à Quimioterapia em Pacientes com Câncer de Pulmão Avaliada pelo Escore Angiográfico SYNTAX / Chemotherapy-Related Anatomical Coronary-Artery Disease in Lung Cancer Patients Evaluated by Coronary-Angiography SYNTAX Score

Resumo Fundamento A doença arterial coronariana (DAC) associada à quimioterapia está se tornando um tema emergente na prática clínica. Contudo, o mecanismo subjacente da quimioterapia associada à DAC permanence incerto. Objetivos O estudo investigou a associação entre a quimioterapia e as anomalias anatômicas ateroscleróticas das artérias coronárias dentre pacientes com cancer de pulmão. Métodos Foram incluídos pacientes submetidos à angiografia coronária (AGC), entre 2010 e 2017, com câncer de pulmão prévio. Os fatores de risco associados à DAC e os dados sobre o câncer de pulmão foram avaliados. Avaliamos as anomalias das artérias coronárias de acordo com o escore SYNTAX (SXescore) calculado à AGC. Na análise de regressão logística, o escore SYNTAX foi classificado como alto (SXescoreALTO) se ≥22. Os dados foram analisados através de estatística descritiva e análise de regressão. Resultados Ao todo, 94 pacientes foram incluídos no estudo. O SXescore foi mais alto no grupo com quimioterapia quando comparado com o grupo sem quimioterapia (25,25, IIQ [4,50-30,00] versus 16,50, IIQ [5,00-22,00]; p = 0,0195). A taxa do SXescoreALTO foi maior no grupo com quimioterapia do que no no grupo sem quimioterapia (58,33% versus 25,86; p = 0,0016). Tanto a análise de regressão logística univariada (OR: 4,013; 95% IC:1,655-9,731) quanto a multivariada (OR: 5,868; 95% IC:1,778-19,367) revelaram que a quimioterapia aumentou o risco de uma maior taxa do SXescoreALTO. A análise multivariada de regressão logística Stepwise mostrou que o risco para DAC anatômica mais grave aumenta com a quimioterapia como um todo em 5.323 vezes (95% IC: 2,002-14,152), e com o regime à base de platina em 5,850 vezes (95% IC: 2,027-16,879). Conclusões A quimioterapia está associada com a complexidade e gravidade anatômica da DAC, o que pode explicar, em parte, o maior risco de DAC associada à quimioterapia dentre pacientes com câncer de pulmão. (Arq Bras Cardiol. 2020; [online].ahead print, PP.0-0)

Abstract Background Chemotherapy-related coronary artery disease (CAD) is becoming an emerging issue in clinic. However, the underlying mechanism of chemotherapy-related CAD remains unclear. Objective The study investigated the association between chemotherapy and atherosclerotic anatomical abnormalities of coronary arteries among lung cancer patients. Methods Patients undergoing coronary angiography (CAG) between 2010 and 2017, who previously had lung cancer, were examined. Risk factors associated with CAD and information about lung cancer were evaluated. We assessed coronary-artery abnormalities by SYNTAX score (SXscore) based on CAG. In logistic-regression analysis, we defined high SXscore (SXhigh) grade as positive if ≥22. Data were analyzed through descriptive statistics and regression analysis. Results A total of 94 patients were included in the study. The SXscore was higher in the chemotherapy group than in the non-chemotherapy group (25.25, IQR [4.50-30.00] vs. 16.50, IQR [ 5.00-22.00], p = 0.0195). The SXhigh rate was greater in the chemotherapy group than in the non-chemotherapy group (58.33% vs. 25.86; p = 0.0016). Both univariate (OR:4.013; 95% CI:1.655-9.731) and multivariate (OR:5.868; 95% CI:1.778-19.367) logistic-regression analysis revealed that chemotherapy increased the risk of greater SXhigh rates. Multivariate stepwise logistic-regression analysis showed the risk of more severe anatomical CAD is increased by chemotherapy as a whole by 5.323 times (95% CI: 2.002-14.152), and by platinum-based regimens by 5.850 times (95% CI: 2.027-16.879). Conclusions Chemotherapy is associated with anatomical complexity and severity of CAD, which might partly account for the higher risk of chemotherapy-related CAD among lung cancer patients. (Arq Bras Cardiol. 2020; [online].ahead print, PP.0-0)

Pirfenidone alleviates lipopolysaccharide-induced lung injury by accentuating BAP31 regulation of ER stress and mitochondrial injury.

Pirfenidone has been widely used in the treatment of idiopathic pulmonary fibrosis (IPF). However, the role of pirfenidone in LPS-induced acute lung injury (ALI) remains unclear. This study aims to investigate the protective effects of pirfenidone in ALI and to explore its underlying mechanism. Pirfenidone clearly reduces LPS-triggered ALI as indicated by significant pathological alterations, reduced oxidative stress and inflammatory responses in vivo. Furthermore, pirfenidone also blocks apoptosis of LPS-induced alveolar epithelial type II (ATII) cells through inhibition of endoplasmic reticulum (ER) stress and mitochondrial injury in vivo and in vitro. A lower expression level of BAP31, an ER transmembrane protein, was found to be associated with ALI followed LPS challenge. The reintroduction of BAP31 blunted LPS induced ER stress and mitochondrial damage and therefore alleviated ATII cell apoptosis, which correlated with pirfenidone treatment. Knockdown of BAP31 expression in pirfenidone treated ATII cells re-activated ER stress, mitochondrial damage and followed cellular apoptosis. In summary, this study confirms the beneficial effect of pirfenidone on ER stress and mitochondrial dysfunction mediated apoptosis via upregulation of BAP31. Our results demonstrated that pirfenidone may be considered as a potential agent for the treatment of ALI in the future.

Chemotherapy-Related Anatomical Coronary-Artery Disease in Lung Cancer Patients Evaluated by Coronary-Angiography SYNTAX Score. / Doença Arterial Coronariana Anatômica Associada à Quimioterapia em Pacientes com Câncer de Pulmão Avaliada pelo Escore Angiográfico SYNTAX.

Background Chemotherapy-related coronary artery disease (CAD) is becoming an emerging issue in clinic. However, the underlying mechanism of chemotherapy-related CAD remains unclear. Objective The study investigated the association between chemotherapy and atherosclerotic anatomical abnormalities of coronary arteries among lung cancer patients. Methods Patients undergoing coronary angiography (CAG) between 2010 and 2017, who previously had lung cancer, were examined. Risk factors associated with CAD and information about lung cancer were evaluated. We assessed coronary-artery abnormalities by SYNTAX score (SXscore) based on CAG. In logistic-regression analysis, we defined high SXscore (SXhigh) grade as positive if ≥22. Data were analyzed through descriptive statistics and regression analysis. Results A total of 94 patients were included in the study. The SXscore was higher in the chemotherapy group than in the non-chemotherapy group (25.25, IQR [4.50-30.00] vs. 16.50, IQR [ 5.00-22.00], p = 0.0195). The SXhigh rate was greater in the chemotherapy group than in the non-chemotherapy group (58.33% vs. 25.86; p = 0.0016). Both univariate (OR:4.013; 95% CI:1.655-9.731) and multivariate (OR:5.868; 95% CI:1.778-19.367) logistic-regression analysis revealed that chemotherapy increased the risk of greater SXhigh rates. Multivariate stepwise logistic-regression analysis showed the risk of more severe anatomical CAD is increased by chemotherapy as a whole by 5.323 times (95% CI: 2.002-14.152), and by platinum-based regimens by 5.850 times (95% CI: 2.027-16.879). Conclusions Chemotherapy is associated with anatomical complexity and severity of CAD, which might partly account for the higher risk of chemotherapy-related CAD among lung cancer patients. (Arq Bras Cardiol. 2020; [online].ahead print, PP.0-0).

Clinical Features of 85 Fatal Cases of COVID-19 from Wuhan. A Retrospective Observational Study.

Rationale: The global death toll from coronavirus disease (COVID-19) virus as of May 12, 2020, exceeds 286,000. The risk factors for death were attributed to advanced age and comorbidities but have not been accurately defined.Objectives: To report the clinical features of 85 fatal cases of COVID-19 in two hospitals in Wuhan.Methods: Medical records were collected of 85 fatal cases of COVID-19 between January 9, 2020, and February 15, 2020. Information recorded included medical history, exposure history, comorbidities, symptoms, signs, laboratory findings, computed tomographic scans, and clinical management.Measurements and Main Results: The median age of the patients was 65.8 years, and 72.9% were male. Common symptoms were fever (78 [91.8%]), shortness of breath (50 [58.8%]), fatigue (50 [58.8%]), and dyspnea (60 [70.6%]). Hypertension, diabetes, and coronary heart disease were the most common comorbidities. Notably, 81.2% of patients had very low eosinophil counts on admission. Complications included respiratory failure (80 [94.1%]), shock (69 [81.2%]), acute respiratory distress syndrome (63 [74.1%]), and arrhythmia (51 [60%]), among others. Most patients received antibiotic (77 [90.6%]), antiviral (78 [91.8%]), and glucocorticoid (65 [76.5%]) treatments. A total of 38 (44.7%) and 33 (38.8%) patients received intravenous immunoglobulin and IFN-α2b, respectively.Conclusions: In this depictive study of 85 fatal cases of COVID-19, most cases were males aged over 50 years with noncommunicable chronic diseases. The majority of the patients died of multiple organ failure. Early onset of shortness of breath may be used as an observational symptom for COVID-19 exacerbations. Eosinophilopenia may indicate a poor prognosis. A combination of antimicrobial drugs did not offer considerable benefit to the outcome of this group of patients.

Correction to: DNA­PKcs promotes cardiac ischemia reperfusion injury through mitigating BI­1­governed mitochondrial homeostasis.

Since the publication of the article, the authors found a small problem with Fig. 7e. Unfortunately, Fig. 7e did not contain the correct images. The correct images are shown below and do not change the conclusions.