Background Although metabolic reprogramming is critical in the pathogenesis of heart failure, studies to date have focused principally on fatty acid and glucose metabolism. Contribution of amino acid metabolic regulation in the disease remains understudied. Methods and Results Transcriptomic and metabolomic analyses were performed in mouse failing heart induced by pressure-overload. Suppression of branched-chain amino acids (BCAAs) catabolic gene expression along with concomitant tissue accumulation of branched-chain α-keto acids (BCKAs) was identified as a significant signature of metabolic reprogramming in mouse failing hearts, and validated to be shared in human cardiomyopathy hearts. Molecular and genetic evidence identified the transcription factor KLF15 as a key upstream regulator of the BCAA catabolic regulation in the heart. Studies using a genetic mouse model revealed that BCAA catabolic defect promoted heart failure associated with induced oxidative stress and metabolic disturbance in response to mechanical overload. Mechanistically, elevated BCKA directly suppressed respiration and induced superoxide production in isolated mitochondria. Finally, pharmacological enhancement of branched-chain α-keto acid dehydrogenase activity significantly blunted cardiac dysfunction following pressure-overload. Conclusions BCAA catabolic defect is a metabolic hallmark of failing heart resulted from KLF15 mediated transcriptional reprogramming. BCAA catabolic defect imposes a previously unappreciated significant contribution to heart failure.

COVID-19 has remained an uncontained, worldwide pandemic. While battling for the disease in China, six Traditional Chinese Medicine (TCM) recipes have been shown to be remarkably effective for treating patients with COVID-19. The present review discusses principles of TCM in curing infectious disease, and clinical evidence and mechanisms of the 6 most effective TCM recipes used in treating COVID-19 in 92% of all of the confirmed cases in China. Applications of TCM and specific recipes in the treatment of other viral infections, such as those caused by SARS-CoV, MERS-CoV, hepatitis B virus, hepatitis C virus, influenza A virus (including H1N1 and H7N9), influenza B, dengue virus as well as Ebola virus, are also discussed. Among the 6 TCM recipes, Jinhua Qinggan (JHQG) granules and Lianhua Qingwen (LHQW) capsules are recommended during medical observation; Lung Cleansing and Detoxifying Decoction (LCDD) is recommended for the treatment of both severe and non-severe patients; Xuanfeibaidu (XFBD) granules are recommended for treating moderate cases; while Huashibaidu (HSBD) and Xuebijing (XBJ) have been used in managing severe cases effectively. The common components and the active ingredients of the six TCM recipes have been summarized to reveal most promising drug candidates. The potential molecular mechanisms of the active ingredients in the six TCM recipes that target ACE2, 3CL pro and IL-6, revealed by molecular biological studies and/or network pharmacology prediction/molecular docking analysis/visualization analysis, are fully discussed. Therefore, further investigation of these TCM recipes may be of high translational value in revealing novel targeted therapies for COVID-19, potentially via purification and characterization of the active ingredients in the effective TCM recipes.

Aims/hypothesis We have previously shown that NADPH oxidase (NOX) lies upstream of uncoupled endothelial nitric oxide synthase (eNOS), which is known to occur in diabetic endothelium. However, it remains unclear which specific NOX isoform(s) is responsible for eNOS uncoupling and endothelial dysfunction in diabetic mouse models. The aim of the present study was to test the hypothesis that one or more NOX isoform(s) mediate(s) diabetic uncoupling of eNOS, which has been shown to occur in patients with diabetes to contribute to endothelial dysfunction. Methods Diabetes was induced by streptozotocin administration. The Nω-nitro-L-arginine methyl ester (L-NAME)-sensitive superoxide production of aortic segments, reflective of eNOS uncoupling activity, was determined by electron spin resonance. Results The L-NAME-sensitive superoxide production was more than doubled in wild-type diabetic mice, implicating uncoupling of eNOS. This was abolished in diabetic p47phox−/− (also known as Ncf1−/−) mice, but preserved in Nox2−/y (also known as Cybb−/−) mice made diabetic. The eNOS uncoupling activity was markedly attenuated in diabetic mice transfected with Nox1 or Nox1 organiser 1 (Noxo1) short interfering RNA (siRNA), and abolished in Nox1−/y diabetic mice. Diabetes-induced impairment in endothelium-dependent vasorelaxation was also significantly attenuated in the Nox1−/y mice made diabetic. By contrast, Nox4 siRNA, or inhibition of mitochondrial complex I or III with rotenone or siRNA, respectively, had no effect on diabetic uncoupling of eNOS. Overexpression of Dhfr, or oral administration of folic acid to improve dihydrofolate reductase (DHFR) function, recoupled eNOS in diabetes to improve endothelial function. Conclusions/interpretation Our data demonstrate for the first time that the p47phox and NOXO1-dependent activation of NOX1, but not that of NOX2, NOX4 or mitochondrion, mediates diabetic uncoupling of eNOS. NOX1-null mice are protected from diabetic endothelial dysfunction. Novel approaches to inhibit NOX1 and/or improve DHFR function, may prove to have therapeutic potential for diabetic endothelial dysfunction.

Oxidative stress plays an important role in the formation of abdominal aortic aneurysm (AAA), and we have recently established a causal role of uncoupled eNOS in this severe human disease. We have also shown that activation of NADPH oxidase (NOX) lies upstream of uncoupled eNOS. Therefore, identification of the specific NOX isoforms that are required for eNOS uncoupling and AAA formation would ultimately lead to novel therapies for AAA. In the present study, we used the Ang II infused hph-1 mice to examine the roles of NOX isoforms in the development of AAA. We generated double mutants of hph-1-NOX1, hph-1-NOX2, hph-1-p47phox, and hph-1-NOX4. After two weeks of Ang II infusion, the incidence rate of AAA substantially dropped from 76.5% in Ang II infused hph-1 mice (n=34) to 11.1%, 15.0%, 9.5% and 0% in hph-1-NOX1 (n=27), hph-1-NOX2 (n=40), hph-1-p47phox (n=21), and hph-1-NOX4 (n=33) double mutant mice, respectively. The size of abdominal aortas of the four double mutant mice, determined by ultrasound analyses, was significantly smaller than the hph-1 mice. Aortic nitric oxide and H4B bioavailabilities were markedly improved in the double mutants, while superoxide production and eNOS uncoupling activity were substantially diminished. These effects seemed attributed to an endothelial specific restoration of dihydrofolate reductase expression and activity, deficiency of which has been shown to induce eNOS uncoupling and AAA formation in both Ang II-infused hph-1 and apoE null animals. In addition, over-expression of human NOX4 N129S or T555S mutant newly identified in aneurysm patients increased hydrogen peroxide production, further implicating a relationship between NOX and human aneurysm. Taken together, these data indicate that NOX isoforms 1, 2 or 4 lies upstream of dihydrofolate reductase deficiency and eNOS uncoupling to induce AAA formation. These findings may promote development of novel therapeutics for the treatment of the disease by inhibiting NOX signaling.

Abstract-Calpain was recently reported to mediate vascular endothelial growth factor (VEGF)-induced angiogenesis.In the present study, we investigated detailed molecular mechanisms. VEGF (100 ng/mL) induced a marked increase in endothelial cell production of NO ⅐ , specifically detected by electron spin resonance. This response was abolished by inhibition of calpain with N-acetyl-leucyl-leucyl-norleucinal (ALLN) or Calpeptin. Both also diminished membrane-specific calpain activation by VEGF, which was intriguingly attenuated by silencing ezrin with RNA interference. A rapid membrane colocalization of calpain and ezrin occurred as short as 10 minutes after VEGF stimulation. AKT, AMP-dependent kinase (AMPK), and endothelial nitric oxide synthase (eNOS) s1179 phosphorylations in VEGF-stimulated endothelial cells were markedly enhanced, which were however significantly attenuated by either ALLN, Calpeptin, or ezrin small interfering RNA, as well as by Wortmannin or compound C (respectively for phosphatidylinositol 3-kinase [PI3K] or AMPK). The latter 3 also abolished VEGF induction of NO ⅐ . These data indicate that AMPK and AKT are both downstream of PI3K and that AKT activation is partially dependent on AMPK. The interrelationship between AMPK and AKT, although known to be individually important in mediating VEGF activation of eNOS, is clearly characterized. Furthermore, AMPK/ AKT/eNOS s1179 was found downstream of a calpain/ezrin membrane interaction. These data no doubt provide new insights into the long mystified signaling gap between VEGF receptors and PI3K/AKT or AMPK-dependent eNOS activation. In view of the well-established significance of VEGF-dependent angiogenesis, these findings might have broad and important implications in cardiovascular pathophysiology. (Circ Res. 2009;104:50-59.)

Hypertension and abdominal aortic aneurysm (AAA) are severe cardiovascular diseases with incompletely defined molecular mechanisms. In the current study we generated dihydrofolate reductase (DHFR) knockout mice for the first time to examine its potential contribution to the development of hypertension and AAA, as well as the underlying molecular mechanisms. Whereas the homozygote knockout mice were embryonically lethal, the heterozygote knockout mice had global reduction in DHFR protein expression and activity. Angiotensin II infusion into these animals resulted in substantially exaggerated elevation in blood pressure and development of AAA, which was accompanied by excessive eNOS uncoupling activity (featured by significantly impaired tetrahydrobiopterin and nitric oxide bioavailability), vascular remodeling (MMP2 activation, medial elastin breakdown and adventitial fibrosis) and inflammation (macrophage infiltration). Importantly, scavenging of mitochondrial reactive oxygen species with Mito-Tempo in vivo completely abrogated development of hypertension and AAA in DHFR knockout mice, indicating a novel role of mitochondria in mediating hypertension and AAA downstream of DHFR deficiency-dependent eNOS uncoupling. These data for the first time demonstrate that targeting DHFR-deficiency driven mitochondrial dysfunction may represent an innovative therapeutic option for the treatment of AAA and hypertension.

Bisphenol A [2, 2 bis (4-hydoxyphenyl) propane; BPA] is a widely used endocrine disruptors and has estrogenic activities. Although interests on biological effect of BPA are rising, evidences of its effect on immune system are lacking. We investigated that the effect of BPA on immune parameters to postulate the mechanism, and BPA interruptions between neuroendocrine and immune system. BPA was administrated to mice by p.o. (as a drinking water) dose on 0.015, 1.5 and 30 mg/ml for 4 weeks. The BPA treatment did not result in any change in body weight, spleen weight and distribution of lymphocyte subpopulation collected from spleen. BPA induced prolactin production in spleen, and exposure of BPA increased the activity of splenocyte proliferation in response to Con A (p<0.001). The production of a strong Th-1 type cytokine (IFN-gamma) was induced while Th-2 type (IL-4) was suppressed by BPA treatment. These were consistent with RT-PCR results of transcription factor GATA-3 and IRF-1. These findings suggested that stimulation of prolactin production by estrogenic effects of BPA would affect cytokine profiles, and lead to imbalanced cellular immune response. In addition, we could speculate that prolactin and cytokine is important mediator involved in network between neuroendocrine and immune system by BPA.

The outbreak of COVID-19 has remained uncontained with urgent need for robust therapeutics. Males are more susceptible than females, and more often to develop into severe cases with higher mortality. This predisposition is potentially linked to higher prevalence of cigarette smoking. Nonetheless, we found for the first time that cigarette smoking extract (CSE) had no effect on angiotensin converting enzyme 2 (ACE2) and transmembrane protease serine 2 (TMPRSS2) expression in endothelial cells. The otherwise observed worse outcomes in smokers is likely linked to baseline respiratory diseases associated with chronic smoking. Instead, we hypothesized that estrogen mediated protection might underlie less severe disease in females. Of note, endothelial inflammation and barrier dysfunction are major mediators of disease progression, and development of acute respiratory distress syndrome (ARDS) and multi-organ failure in patients with COVID-19. Therefore, we investigated the protective effects of estrogen on endothelial cells against oxidative stress induced by interleukin-6 (IL-6) and SARS-CoV-2 spike protein (S protein). Indeed, 17β-estradiol completely reversed IL-6 and S protein-induced selective activation of NADPH oxidase isoform 2 (NOX2), reactive oxygen species (ROS) production, ACE2 upregulation and induction of pro-inflammatory gene monocyte chemoattractant protein-1 (MCP-1) in endothelial cells to effectively attenuate endothelial cell dysfunction. Of note, co-treatment with CSE had no additional effects on S protein stimulated endothelial oxidative stress, again indicating that current smoking status is likely unrelated to more severe disease in chronic smokers. These data indicate that estrogen may serve as a novel therapy for patients with COVID-19 via inhibition of initial viral responses and attenuation of cytokine storm induced endothelial dysfunction, to substantially alleviate severity of the disease and mortality, especially in men. Short-term application of estrogen may therefore be readily used in the clinical management of COVID-19 as a robust therapeutic option.