Crosstalk between Interleukin-1 Receptor-Like 1 and Transforming Growth Factor-ß Receptor Signaling Promotes Renal Fibrosis

IL-33, a member of the IL-1 family, acts as an alarmin in immune response. Epithelial-mesenchymal transition and transforming growth factor-ß (TGF-ß)­induced fibroblast activation are key events in the development of renal interstitial fibrosis. The current study found increased expression of IL-33 and interleukin-1 receptor-like 1 (IL1RL1, alias ST2), the receptor for IL-33, in human fibrotic renal tissues. In addition, IL-33­ or ST2-deficient mice showed significantly reduced levels of fibronectin, α-smooth muscle actin, and vimentin, and increased E-cadherin levels. In HK-2 cells, IL-33 promotes the phosphorylation of the TGF-ß receptor (TGF-ßR), Smad2, and Smad3, and the production of extracellular matrix (ECM), with reduced expression of E-cadherin. Blocking TGF-ßR signaling or suppressing ST2 expression impeded Smad2 and Smad3 phosphorylation, thereby reducing ECM production, suggesting that IL-33­induced ECM synthesis requires cooperation between the two pathways. Mechanistically, IL-33 treatment induced a proximate interaction between ST2 and TGF-ßRs, activating downstream Smad2 and Smad3 for ECM production in renal epithelial cells. Collectively, this study identified a novel and essential role for IL-33 in promoting TGF-ß signaling and ECM production in the development of renal fibrosis. Therefore, targeting IL-33/ST2 signaling may be an effective therapeutic strategy for renal fibrosis.

Clinical application of bronchoalveolar lavage fluid metagenomics next-generation sequencing in cancer patients with severe pneumonia.

OBJECTIVE: Metagenomic next-generation sequencing (mNGS), as an emerging technique for pathogen detection, has been widely used in clinic. However, reports on the application of mNGS in cancer patients with severe pneumonia remain limited. This study aims to evaluate the diagnostic performance of bronchoalveolar lavage fluid (BALF) mNGS in cancer patients complicated with severe pneumonia. METHODS: A total of 62 cancer patients with severe pneumonia simultaneously received culture and mNGS of BALF were enrolled in this study. We systematically analyzed the diagnostic significance of BALF mNGS. Subsequently, optimization of anti-infective therapy based on the distribution of pathogens obtained from BALF mNGS was also assessed. RESULTS: For bacteria and fungi, the positive detection rate of mNGS was significantly higher than culture method (91.94% versus 51.61%, P < 0.001), especially for poly-microbial infections (70.97% versus 12.90%, P < 0.001). Compared with the culture method, mNGS exhibited a diagnostic sensitivity of 100% and a specificity of 16.67%, with the positive predictive value (PPV) and negative predictive value (NPV) being 56.14% and 100%, respectively. The agreement rate between these two methods was 59.68%, whereas kappa consensus analysis indicated a poor concordance (kappa = 0.171). After receipt of BALF mNGS results, anti-infective treatment strategies in 39 out of 62 cases (62.90%) were optimized. Moreover, anti-tumor therapy was a high-risk factor for mixed infections (87.18% versus 65.22%, P = 0.04). CONCLUSIONS: The present study showed that cancer patients with severe pneumonia, especially those received anti-tumor therapy, were more likely to have poly-microbial infections. BALF mNGS can provide a rapid and comprehensive pathogen distribution of pulmonary infection, making it a promising technique in clinical practice, especially for optimizing therapeutic strategies for cancer patients.

Anion Exchange Facilitates the In Situ Construction of Bi/BiO Interfaces for Enhanced Electrochemical CO2 -to-Formate Conversion Over a Wide Potential Window.

Electrochemical reduction of CO2 (CO2 RR) into value-added products is a promising strategy to reduce energy consumption and solve environmental issues. Formic acid/formate is one of the high-value, easy-to-collect, and economically viable products. Herein, the reconstructed Bi2 O2 CO3 nanosheets (BOCR NSs) are synthesized by an in situ electrochemical anion exchange strategy from Bi2 O2 SO4 as a pre-catalyst. The BOCR NSs achieve a high formate Faradaic efficiency (FEformate ) of 95.7% at -1.1 V versus reversible hydrogen electrode (vs. RHE), and maintain FEformate above 90% in a wide potential range from -0.8 to -1.5 V in H-cell. The in situ spectroscopic studies reveal that the obtained BOCR NSs undergo the anion exchange from Bi2 O2 SO4 to Bi2 O2 CO3 and further promote the self-reduction to metallic Bi to construct Bi/BiO active site to facilitate the formation of OCHO* intermediate. This result demonstrates anion exchange strategy can be used to rational design high performance of the catalysts toward CO2 RR.

Global, Regional, and National Burden of CKD in Children and Adolescents from 1990 to 2019.

BACKGROUND AND AIMS: CKD is one of the most prevalent non-communicable health concerns in children and adolescents worldwide; however, data on its incidence, prevalence, disability-adjusted life years (DALYs), and trends in the population are limited. We aimed to assess the global, regional, and national trends in CKD burden in children and adolescents. METHODS: In this trend analysis based on the 2019 Global Diseases, Injuries, and Risk Factors Study, CKD incidence, prevalence, and DALYs rates per 100,000 population for children and adolescents were reported at the global, regional, and national levels, as well as the average annual percentage change (AAPC). These global trends were analyzed by age, sex, region, and socio-demographic index (SDI). RESULTS: Globally, the overall incidence of CKD (all stages including KRT) in children and adolescents showed an increasing trend (AAPC 0.44 [95% CI 0.36-0.52]) between 1990 and 2019. Similarly, the overall prevalence of CKD also showed an upward trend (AAPC 0.46 [95% CI 0.42-0.51]). However, the DALYs of CKD showed a continuous decreasing trend (AAPC -1.18[-1.37- -0.99]). The population aged 15-19 years had the largest CKD incidence increase during this period. The largest increase in age-standardized incidence rate (ASIR) was in middle SDI countries (AAPC 0.56 [0.45-0.67]). The relationship between the ASIR and SDI showed an inverse U-shaped correlation while the relationship between the age-standardized DALYs rate (ASDR) and SDI showed an inverse trend with SDI. Among adolescents (15-19 years), the ASIR continued to increase for five causes of CKD, owing to type 2 diabetes mellitus and hypertension. Most of the disease burden was concentrated in countries with a lower SDI. Andean Latin America and Central Latin America showed the largest increases in CKD ASIR between 1990 and 2019. CONCLUSION: The burden of CKD in children and adolescents has increased worldwide, especially in regions and countries with a lower SDI.

Targeting BET proteins inhibited the growth of non-small cell lung carcinoma through downregulation of Met expression.

Hepatocyte growth factor receptor (HGFR or Met) upregulation has been proven to play important roles in non-small cell lung carcinoma (NSCLC). Interestingly, chemoresistance against epidermal growth factor receptor (EGFR) inhibitors including erlotinib and gefitinib was also related to Met. Targeting bromodomain and extra terminal domain (BET) proteins, especially BRD4, has shown inhibitory effects on lung cancer, but the mechanism is unclear. Herein, we found that JQ1 (BET inhibitor) suppressed NSCLC cell growth, reduced the Met expression, and contributed to inactivation of PI3K/Akt and MAPK/ERK pathways. Moreover, another BET protein inhibitor I-BET151, or BRD4 depletion, also inhibited NSCLC cell growth and downregulated Met. JQ1 inhibited HGF-induced cell growth and Met/PI3K/Akt activation, also inhibited A549 tumor growth in xenograft mouse models, in parallel with Met downregulation. Moreover, JQ1 inhibited the growth of paired erlotinib-sensitive and resistant HCC827 cells in parallel with Met downregulation and PI3K/Akt signaling inactivation. JQ1 also exerted inhibitory influences on the growth of erlotinib-sensitive and resistant HCC827 tumors in xenograft mouse models. These results suggested that targeting BET proteins inhibited NSCLC via downregulating Met and inactivating PI3K/AKT pathway. Our findings reveal a novel mechanism of BET proteins implicated in NSCLC progression with Met taken into consideration.

Circulating adiponectin levels and systemic lupus erythematosus: a two-sample Mendelian randomization study.

OBJECTIVES: Several studies have reported increased serum/plasma adiponectin levels in SLE patients. This study was performed to estimate the causal effects of circulating adiponectin levels on SLE. METHODS: We selected nine independent single-nucleotide polymorphisms that were associated with circulating adiponectin levels (P < 5 × 10-8) as instrumental variables from a published genome-wide association study (GWAS) meta-analysis. The corresponding effects between instrumental variables and outcome (SLE) were obtained from an SLE GWAS analysis, including 7219 cases with 15 991 controls of European ancestry. Two-sample Mendelian randomization (MR) analyses with inverse-variance weighted, MR-Egger regression, weighted median and weight mode methods were used to evaluate the causal effects. RESULTS: The results of inverse-variance weighted methods showed no significantly causal associations of genetically predicted circulating adiponectin levels and the risk for SLE, with an odds ratio (OR) of 1.38 (95% CI 0.91, 1.35; P = 0.130). MR-Egger [OR 1.62 (95% CI 0.85, 1.54), P = 0.195], weighted median [OR 1.37 (95% CI 0.82, 1.35), P = 0.235) and weighted mode methods [OR 1.39 (95% CI 0.86, 1.38), P = 0.219] also supported no significant associations of circulating adiponectin levels and the risk for SLE. Furthermore, MR analyses in using SLE-associated single-nucleotide polymorphisms as an instrumental variable showed no associations of genetically predicted risk of SLE with circulating adiponectin levels. CONCLUSION: Our study did not find evidence for a causal relationship between circulating adiponectin levels and the risk of SLE or of a causal effect of SLE on circulating adiponectin levels.

Trichostatin A downregulates bromodomain and extra-terminal proteins to suppress osimertinib resistant non-small cell lung carcinoma.

BACKGROUND: The third-generation epithelial growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) have shown significant therapeutic effects on patients with non-small cell lung carcinoma (NSCLC) who carry active EGFR mutations, as well as those who have developed acquired resistance to the first-generation of EGFR-TKIs due to the T790M mutation. However, most patients develop drug resistance after 8-10 months of treatment. Currently, the mechanism has not been well clarified, and new therapeutic strategies are urgently needed. METHODS: Osimertinib resistant cell lines were established by culturing sensitive cells in chronically increasing doses of osimertinib. The anticancer effect of reagents was examined both in vitro and in vivo using the sulforhodamine B assay and a xenograft mouse model. The molecular signals were detected by western blotting. The combination effect was analyzed using CompuSyn software. RESULTS: We found that bromodomain and extra-terminal proteins (BETs) were upregulated in osimertinib resistant (H1975-OR) cells compared with those in the paired parental cells (H1975-P), and that knockdown of BETs significantly inhibited the growth of H1975-OR cells. The BET inhibitor JQ1 also exhibited stronger growth-inhibitory effects on H1975-OR cells and a greater expression of BETs and the downstream effector c-Myc than were observed in H1975-P cells. The histone deacetylase (HDAC) inhibitor trichostatin A (TSA) showed stronger growth suppression in H1975-OR cells than in H1975-P cells, but vorinostat, another HDAC inhibitor, showed equal inhibitory efficacy in both cell types. Consistently, downregulation of BET and c-Myc expression was greater with TSA than with vorinostat. TSA restrained the growth of H1975-OR and H1975-P xenograft tumors. The combination of TSA and JQ1 showed synergistic growth-inhibitory effects in parallel with decreased BET and c-Myc expression in both H1975-OR and H1975-P cells and in xenograft nude mouse models. BETs were not upregulated in osimertinib resistant HCC827 cells compared with parental cells, while TSA and vorinostat exhibited equal inhibitory effects on both cell types. CONCLUSION: Upregulation of BETs contributed to the osimertinib resistance of H1975 cells. TSA downregulated BET expression and enhanced the growth inhibitory effect of JQ1 both in vitro and in vivo. Our findings provided new strategies for the treatment of osimertinib resistance.

Gradient Diffusion Anisotropic Carboxymethyl Cellulose Hydrogels for Strain Sensors.

Recently, because of the unique properties of anisotropic and isotropic structures, there are more research studies on anisotropic hydrogels. We prepared a gradient anisotropic carboxymethyl cellulose hydrogel (CMC-Al3+) by directionally diffusing aluminum chloride solution. The orientation of carboxymethyl cellulose (CMC) chains is perpendicular to the direction of aluminum ion diffusion. The degree of cross-linking and orientation gradually decrease along the direction of aluminum ion diffusion. Compared with anisotropic hydrogels prepared by other methods, the hydrogels prepared by directionally diffusing aluminum ion solution have a gradient lamellar structure. Because of the large amount of aluminum ions in CMC-Al3+, the hydrogel shows good sensing performance. CMC-Al3+ is packaged with PVC electrical flame retardant tape to produce a strain sensor used to detect human tiny movements, which can accurately and stably monitor tiny movements. Hydrogel-based strain sensors can be widely used in the fields of human-computer intelligence, human-computer interaction, and wearable devices in the future.

Predictors of coronary artery calcification and its association with cardiovascular events in patients with chronic kidney disease.

OBJECTIVE: To investigate the predictors of coronary artery calcification (CAC) and its association with cardiovascular events (CVE) in patients with stage 3-5 chronic kidney disease (CKD). METHOD: Two hundred ninety CKD patients in our nephrology department were enrolled from 2018 to May 2019. The levels of matrix Gla protein (MGP) and interleukin 6 (IL-6) were measured via enzyme-linked immunosorbent assay (ELISA) method in 131 CKD patients of all. CAC was evaluated via computed tomography (CT). The covariate factors were analyzed by binary logistic regression analysis. We conducted the visits to explore the prevalence of CVE in 276 CKD patients, and covariate factors were analyzed by Cox proportional hazard model. RESULTS: The prevalence of CAC was up to 57.93%. We found that age, diabetes mellitus, hyperphosphatemia, dialysis duration, and the neutrophil-lymphocyte ratio (NLR) were positively associated with CAC in all patients. In 131 patients, we demonstrated that higher IL-6 and lower MGP levels were associated with CAC. A Cox proportional hazard model demonstrated that moderate to severe CAC was correlated with an increased risk for CVE [Hazard Ratio (HR): 7.250; 95% confidence interval (CI): 3.192-16.470], and a higher MGP level was associated with a reduced risk for CVE (HR: 0.340; 95% CI: 0.124-0.933). CONCLUSIONS: The prevalence of CAC in patients with CKD is a significant issue. Older age, hyperphosphatemia, dialysis duration, diabetes mellitus, IL-6, and the NLR are associated with CAC. In addition, higher MGP levels represent protective factor for CAC. Moderate to severe CAC, and lower MGP levels are associated with an increased risk for CVE. Abbreviations: AGEs: Advanced glycosylation end products; CAC: Coronary artery calcification; CACS: Coronary artery calcification score; Ca: Calcium; CI: confidence interval; CKD: Chronic kidney disease; CVE: Cardiovascular events; CT: Computed tomography; ELISA: Enzyme-linked immunosorbent assay; Hb: hemoglobin; HR: Hazard ratio; hs-CRP: high-sensitivity C-reactive protein; IL-6: Interleukin 6; iPTH: Intact parathyroid hormone; Mg: Magnesium; MGP: Matrix Gla protein; NF-κB: nuclear factor-kappa gene binding; NRL: Neutrophil-lymphocyte ratio; Runx2: Runt-related transcription factor 2; RRT: Renal replacement therapy; P: Phosphorus; Scr: Serum creatinine; TNF--alpha: Tumor necrosis factor--alpha; TC: Total cholesterol; TG: Triglyceride; VSMC: vascular smooth muscle cel.

Enhanced Redox State and Efficiency of Glucose Oxidation With miR Based Suppression of Maladaptive NADPH-Dependent Malic Enzyme 1 Expression in Hypertrophied Hearts.

RATIONALE: Metabolic remodeling in hypertrophic hearts includes inefficient glucose oxidation via increased anaplerosis fueled by pyruvate carboxylation. Pyruvate carboxylation to malate through elevated ME1 (malic enzyme 1) consumes NADPH necessary for reduction of glutathione and maintenance of intracellular redox state. OBJECTIVE: To elucidate upregulated ME1 as a potential maladaptive mechanism for inefficient glucose oxidation and compromised redox state in hypertrophied hearts. METHODS AND RESULTS: ME1 expression was selectively inhibited, in vivo, via non-native miR-ME1 (miRNA specific to ME1) in pressure-overloaded rat hearts. Rats subjected to transverse aortic constriction (TAC) or Sham surgery received either miR-ME1 or PBS. Effects of ME1 suppression on anaplerosis and reduced glutathione (GSH) content were studied in isolated hearts supplied 13C-enriched substrate: palmitate, glucose, and lactate. Human myocardium collected from failing and nonfailing hearts during surgery enabled RT-qPCR confirmation of elevated ME1 gene expression in clinical heart failure versus nonfailing human hearts (P<0.04). TAC induced elevated ME1 content, but ME1 was lowered in hearts infused with miR-ME1 versus PBS. Although Sham miR-ME1 hearts showed no further reduction of inherently low anaplerosis in normal heart, miR-ME1 reduced anaplerosis in TAC to baseline: TAC miR-ME1=0.034±0.004; TAC PBS=0.081±0.005 (P<0.01). Countering elevated anaplerosis in TAC shifted pyruvate toward oxidation in the tricarboxylic acid cycle. Importantly, via the link to NADPH consumption by pyruvate carboxylation, ME1 suppression in TAC restored GSH content, reduced lactate production, and ultimately improved contractility. CONCLUSIONS: A maladaptive increase in anaplerosis via ME1 in TAC is associated with reduced GSH content. Suppressing increased ME1 expression in hypertrophied rat hearts, which is also elevated in failing human hearts, reduced pyruvate carboxylation thereby normalizing anaplerosis, restoring GSH content, and reducing lactate accumulation. Reducing ME1 induced favorable metabolic shifts for carbohydrate oxidation, improving intracellular redox state and enhanced cardiac performance in pathological hypertrophy.

Prevalence of coronary artery calcification and its association with mortality, cardiovascular events in patients with chronic kidney disease: a systematic review and meta-analysis.

PURPOSE: To date, the prevalence and prognostic role of coronary artery calcification (CAC) in patients with chronic kidney disease (CKD) have been investigated in several studies, but have yielded conflicting results. The aim of this meta-analysis is to derive a more precise estimation of CAC prevalence in CKD patients and its association with cardiovascular events and mortality. METHODS: The relevant literature was identified and evaluated from inception until July 2018 through multiple search strategies on PubMed, Embase, and Web of Science. Cross-sectional or cohort (baseline data) studies reporting CAC prevalence were included. Data extracted from eligible studies were used to calculate effect estimates (ESs) and 95% confidence intervals (95%CI). We searched databases for observational studies that explored baseline CAC and subsequent cardiovascular or all-cause mortality risk in CKD patients. RESULTS: The meta-analysis included 47 studies; 38 of these were included in the final analysis of CAC prevalence. The pooled prevalence of CAC in random effect model was 60% (95%CI 53-68%). CAC was positively associated with an increased risk of all-cause mortality (hazard ratio [HR] 3.44; 95%CI 2.40-4.94), cardiovascular mortality (HR 3.87; 95%CI 2.06-7.26), and cardiovascular events (HR 2.09; 95%CI 1.19-3.67), when comparing individuals in the top CAC score group to those in the bottom CAC score group. CONCLUSIONS: The pooled prevalence of CAC is highly prevalent. CAC is independently associated with all-cause and cardiovascular mortality risk as well as cardiovascular events among CKD patients. In view of the high heterogeneity, larger clinical trials are still needed.

AEG-1 induces gastric cancer metastasis by upregulation of eIF4E expression.

Gastric cancer is the third leading cause of cancer-related deaths worldwide, and patients with lymph node, peritoneal and distant metastasis have a poor prognosis. Overexpression of Astrocyte-elevated gene-1 (AEG-1) has been reported to be correlated with the progression and metastasis of gastric cancer. However, its mechanisms are quite unclear. In this study, we found that elevated expression of AEG-1 was correlated with metastasis in human gastric cancer tissues. Moreover, gain- or loss-of-function of AEG-1, respectively, promoted or suppressed epithelial-mesenchymal transition (EMT), migration and invasion of gastric cancer cells. AEG-1 positively regulated eIF4E, MMP-9 and Twist expression. Manipulating eIF4E expression by transfection of overexpression constructs or siRNAs partially eliminated AEG-1-regulated EMT, cell migration and invasion. In addition, overexpression or knockdown of eIF4E promoted or suppressed EMT, cell migration and invasion in parallel with upregulation of MMP-9 and Twist expression, while manipulating eIF4E expression partially abrogated AEG-1-induced MMP-9 and Twist. Finally, silencing of AEG-1 expression not only inhibited tumour growth in parallel with downregulation of eIF4E, MMP-9 and Twist expression in a xenograft nude mouse model, but also suppressed lymph node and peritoneal metastasis of gastric cancer in an orthotopic nude mouse model. These findings suggest that AEG-1 promotes gastric cancer metastasis through upregulation of eIF4E-mediated MMP-9 and Twist, which provides new diagnostic markers and therapeutic targets for cancer metastasis.

Glycyrrhizin inhibits LPS-induced inflammatory mediator production in endometrial epithelial cells.

Endometriosis is a continuous inflammation of uterine endometrium that usually affects women of reproductive age. Glycyrrhizin, a triterpene isolated from the roots and rhizomes of licorice (Glycyrrhiza glabra), has been known to have anti-inflammatory effect. The purpose of this study was to investigate the anti-inflammatory effect of glycyrrhizin on LPS-stimulated mouse endometrial epithelial cells (MEEC). The levels of TNF-α, IL-1ß, and PGE2 were measured by ELISA. The expression of COX-2, iNOS, TLR4, and NF-ĸB were detected by western blot analysis. The results showed that glycyrrhizin significantly suppressed LPS-induced TNF-α, IL-1ß, NO, and PGE2 production. Also, LPS-induced iNOS and COX-2 expression were attenuated by glycyrrhizin. Furthermore, glycyrrhizin significantly attenuated TLR4 expression and NF-κB activation induced by LPS in MEEC. In conclusion, the present study demonstrated that glycyrrhizin inhibited LPS-induced inflammatory response by inhibiting TLR4 signaling pathway in MEEC. Glycyrrhizin may be used as a potential agent for the treatment of endometriosis.

Serum sclerostin values are associated with abdominal aortic calcification and predict cardiovascular events in patients with chronic kidney disease stages 3-5D.

AIM: The purpose of this study was to investigate the possible association of circulating concentrations of sclerostin with abdominal aortic calcification (AAC) and cardiovascular outcomes in patients with chronic kidney disease stage 3-5. METHODS: One hundred and sixty-one patients with CKD3-5D were enrolled. The patients were divided into two groups according to the presence of AAC: an AAC group (n = 99) and a non-AAC group (n = 62). The concentration of serum sclerostin was measured using an enzyme-linked immunosorbent assay (ELISA). AAC was evaluated using abdominal lateral X-ray examination. The follow-up intervals ranged from 7 to 29 months (median 16 months), and cardiovascular events (CVEs) were recorded. RESULTS: The prevalence of vascular calcification (VC) was 61.5% (99/161). Serum sclerostin was significantly higher in an AAC group than in a non-AAC group (P < 0.001), but the concentration in the moderate-to-severe AAC group was lower than in the mild AAC group (P < 0.001). Binary logistic regression analysis revealed that high serum sclerostin, high serum calcium, diabetes, and old age were independently correlated with AAC. Patients with higher sclerostin values had a reduced risk of major cardiovascular events (log-rank test, P = 0.001). CONCLUSION: Serum sclerostin values are associated with the presence of AAC, but are lower when AAC is moderate to severe. Higher values are predictive of reduced short-term cardiovascular events. Taken together, these results suggest that sclerostin may have a role in the development of or the response to vascular calcification.

Acyl CoA synthetase-1 links facilitated long chain fatty acid uptake to intracellular metabolic trafficking differently in hearts of male versus female mice.

RATIONALE: Acyl CoA synthetase-1 (ACSL1) is localized at intracellular membranes, notably the mitochondrial membrane. ACSL1 and female sex are suggested to indirectly facilitate lipid availability to the heart and other organs. However, such mechanisms in intact, functioning myocardium remain unexplored, and roles of ACSL1 and sex in the uptake and trafficking of fats are poorly understood. OBJECTIVE: To determine the potential for ACSL1 and sex-dependent differences in metabolic trapping and trafficking effects of long-chain fatty acids (LCFA) within cardiomyocytes of intact hearts. METHODS AND RESULTS: (13)C NMR of intact, beating mouse hearts, supplied (13)C palmitate, revealed 44% faster trans-sarcolemmal uptake of LCFA in male hearts overexpressing ACSL1 (MHC-ACSL1) than in non-transgenic (NTG) males (p<0.05). Acyl CoA content was elevated by ACSL1 overexpression, 404% in males and 164% in female, relative to NTG. Despite similar ACSL1 content, NTG females displayed faster LCFA uptake kinetics compared to NTG males, which was reversed by ovariectomy. NTG female LCFA uptake rates were similar to those in ACSL1 males and ACSL1 females. ACSL1 and female sex hormones both accelerated LCFA uptake without affecting triglyceride content or turnover. ACSL1 hearts contained elevated ceramide, particularly C22 ceramide in both sexes and specifically, C24 in males. ACSL1 also induced lower content of fatty acid transporter-6 (FATP6) indicating cooperative regulation with ACSL1. Surprisingly, ACSL1 overexpression did not increase mitochondrial oxidation of exogenous palmitate, which actually dropped in female ACSL1 hearts. CONCLUSIONS: ACSL1-mediated metabolic trapping of exogenous LCFA accelerates LCFA uptake rates, albeit to a lesser extent in females, which distinctly affects LCFA trafficking to acyl intermediates but not triglyceride storage or mitochondrial oxidation and is affected by female sex hormones.

Dietary fat supply to failing hearts determines dynamic lipid signaling for nuclear receptor activation and oxidation of stored triglyceride.

BACKGROUND: Intramyocardial triglyceride (TG) turnover is reduced in pressure-overloaded, failing hearts, limiting the availability of this rich source of long-chain fatty acids for mitochondrial ß-oxidation and nuclear receptor activation. This study explored 2 major dietary fats, palmitate and oleate, in supporting endogenous TG dynamics and peroxisome proliferator-activated receptor-α activation in sham-operated (SHAM) and hypertrophied (transverse aortic constriction [TAC]) rat hearts. METHODS AND RESULTS: Isolated SHAM and TAC hearts were provided media containing carbohydrate with either (13)C-palmitate or (13)C-oleate for dynamic (13)C nuclear magnetic resonance spectroscopy and end point liquid chromatography/mass spectrometry of TG dynamics. With palmitate, TAC hearts contained 48% less TG versus SHAM (P=0.0003), whereas oleate maintained elevated TG in TAC, similar to SHAM. TG turnover in TAC was greatly reduced with palmitate (TAC, 46.7±12.2 nmol/g dry weight per min; SHAM, 84.3±4.9; P=0.0212), as was ß-oxidation of TG. Oleate elevated TG turnover in both TAC (140.4±11.2) and SHAM (143.9±15.6), restoring TG oxidation in TAC. Peroxisome proliferator-activated receptor-α target gene transcripts were reduced by 70% in TAC with palmitate, whereas oleate induced normal transcript levels. Additionally, mRNA levels for peroxisome proliferator-activated receptor-γ-coactivator-1α and peroxisome proliferator-activated receptor-γ-coactivator-1ß in TAC hearts were maintained by oleate. With these metabolic effects, oleate also supported a 25% improvement in contractility over palmitate with TAC (P=0.0202). CONCLUSIONS: The findings link reduced intracellular lipid storage dynamics to impaired peroxisome proliferator-activated receptor-α signaling and contractility in diseased hearts, consistent with a rate-dependent lipolytic activation of peroxisome proliferator-activated receptor-α. In decompensated hearts, oleate may serve as a beneficial energy substrate versus palmitate by upregulating TG dynamics and nuclear receptor signaling.

Oroxylin A induces autophagy in human malignant glioma cells via the mTOR-STAT3-Notch signaling pathway.

Autophagy is a tightly-regulated catabolic pathway involving degradation of cellular proteins, cytoplasm and organelles. Recent evidence suggests that autophagy plays a potential role in cell death as a tumor suppressor and that its induction especially in combination with apoptosis could be beneficial. It remains unclear if all cancer cells behave the same mechanism when autophagy is induced. Although mammalian target of rapamycin (mTOR) is well known as a negative regulator of autophagy, the relationship between signal transducer and activator of transcription 3 (STAT3) and autophagy has not yet been investigated. Oroxylin A, a natural mono-flavonoid extracted from Scutellariae radix, is a promising therapeutic agent for treating multiple cancers. Here we investigated the mechanism underlying the effect of oroxylin A on malignant glioma cells. We showed that oroxylin A inhibited the proliferation of malignant glioma cells by inducing autophagy in a dose- and time-dependent manner. Oroxylin A treatment inhibits the AKT and ERK activation and the downstream phosphorylation level of mTOR and STAT3. In addition, oroxylin A treatment decreases the expression of Notch-1 and myeloid cell leukemia-1 (Mcl-1) but upregulates Beclin 1, the key autophagy-related protein. 3-MA (autophagy inhibitor) or knockdown of Beclin 1 partially can rescue cells from oroxylin A-induced autophagic cell death. In contrast, knockdown of STAT3 aggravates oroxylin A-induced autophagic cell death. Our data reveal an important role of autophagy in enhancing cell death induced by oroxylin A and conclude that oroxylin A exerts anti-malignant glioma proficiency by inducing autophagy via the ERK/AKT-mTOR-STAT3-Notch signaling cascade.

Acute liver carnitine palmitoyltransferase I overexpression recapitulates reduced palmitate oxidation of cardiac hypertrophy.

RATIONALE: Muscle carnitine palmitoyltransferase I is predominant in the heart, but the liver isoform (liver carnitine palmitoyltransferase I [L-CPT1]) is elevated in hearts with low long chain fatty acid oxidation, such as fetal and hypertrophied hearts. OBJECTIVE: This work examined the effect of acute L-CPT1 expression on the regulation of palmitate oxidation and energy metabolism in intact functioning rat hearts for comparison with findings in hypertrophied hearts. METHODS AND RESULTS: L-CPT1 was expressed in vivo in rat hearts by coronary perfusion of Adv.cmv.L-CPT1 (L-CPT1, n=15) vs. phosphate-buffered saline (PBS) infusion (PBS, n=7) or empty virus (empty, n=5). L-CPT1 was elevated 5-fold at 72 hours after Adv.cmv.L-CPT1 infusion (P<0.05), but muscle carnitine palmitoyltransferase I was unaffected. Despite similar tricarboxylic acid cycle rates, palmitate oxidation rates were reduced with L-CPT1 (1.12 ± 0.29 µmol/min per gram of dry weight, mean±SE) vs. PBS (1.6 ± 0.34). Acetyl CoA production from palmitate was reduced with L-CPT1 (69 ± 0.02%; P<0.05; PBS=79 ± 0.01%; empty=81 ± 0.02%), similar to what occurs in hypertrophied hearts, and with no difference in malonyl CoA content. Glucose oxidation was elevated with L-CPT1 (by 60%). Surprisingly, L-CPT1 hearts contained elevated atrial natriuretic peptide, indicating induction of hypertrophic signaling. CONCLUSIONS: The results link L-CPT1 expression to reduced palmitate oxidation in a nondiseased adult heart, recapitulating the phenotype of reduced long chain fatty acid oxidation in cardiac hypertrophy. The implications are that L-CPT1 expression induces metabolic remodeling hypertrophic signaling and that regulatory factors beyond malonyl CoA in the heart regulate long chain fatty acid oxidation via L-CPT1.

Protein phosphatase 2A and DNA-dependent protein kinase are involved in mediating rapamycin-induced Akt phosphorylation.

BACKGROUND: The mechanisms underlying rapamycin-induced Akt phosphorylation have not been fully elucidated. RESULTS: Inhibition of PP2A or DNA-PK attenuates or abrogates rapamycin-induced Akt phosphorylation and co-inhibition of mTOR and DNA-PK enhances anticancer activity. CONCLUSION: PP2A-dependent and DNA-PK-mediated mechanism is involved in rapamycin-induced Akt phosphorylation. SIGNIFICANCE: A previously unknown mechanism underlying rapamycin-induced Akt phosphorylation and a novel strategy to enhance mTOR-targeted cancer therapy may be suggested. Inhibition of mammalian target of rapamycin complex 1 (mTORC1), for example with rapamycin, increases Akt phosphorylation while inhibiting mTORC1 signaling. However, the underlying mechanisms have not been fully elucidated. The current study has uncovered a previously unknown mechanism underlying rapamycin-induced Akt phosphorylation involving protein phosphatase 2A (PP2A)-dependent DNA protein kinase (DNA-PK) activation. In several cancer cell lines, inhibition of PP2A with okadaic acid, fostriecin, small T antigen, or PP2A knockdown abrogated rapamycin-induced Akt phosphorylation, and rapamycin increased PP2A activity. Chemical inhibition of DNA-PK, knockdown or deficiency of DNA-PK catalytic subunit (DNA-PKcs), or knock-out of the DNA-PK component Ku86 inhibited rapamycin-induced Akt phosphorylation. Exposure of cancer cells to rapamycin increased DNA-PK activity, and gene silencing-mediated PP2A inhibition attenuated rapamycin-induced DNA-PK activity. Collectively these results suggest that rapamycin induces PP2A-dependent and DNA-PK-mediated Akt phosphorylation. Accordingly, simultaneous inhibition of mTOR and DNA-PK did not stimulate Akt activity and synergistically inhibited the growth of cancer cells both in vitro and in vivo. Thus, our findings also suggest a novel strategy to enhance mTOR-targeted cancer therapy by co-targeting DNA-PK.

Akt phosphorylation regulates the tumour-suppressor merlin through ubiquitination and degradation.

The neurofibromatosis-2 (NF2) tumour-suppressor gene encodes an intracellular membrane-associated protein, called merlin, whose growth-suppressive function is dependent on its ability to form interactions through its intramolecular amino-terminal domain (NTD) and carboxy-terminal domain (CTD). Merlin phosphorylation plays a critical part in dictating merlin NTD/CTD interactions as well as in controlling binding to its effector proteins. Merlin is partially regulated by phosphorylation of Ser 518, such that hyperphosphorylated merlin is inactive and fails to form productive intramolecular and intermolecular interactions. Here, we show that the protein kinase Akt directly binds to and phosphorylates merlin on residues Thr 230 and Ser 315, which abolishes merlin NTD/CTD interactions and binding to merlin's effector protein PIKE-L and other binding partners. Furthermore, Akt-mediated phosphorylation leads to merlin degradation by ubiquitination. These studies demonstrate that Akt-mediated merlin phosphorylation regulates the function of merlin in the absence of an inactivating mutation.