DNA sensing via the cGAS/STING pathway activates the immunoproteasome and adaptive T-cell immunity.

The immunoproteasome is a specialized type of proteasome involved in MHC class I antigen presentation, antiviral adaptive immunity, autoimmunity, and is also part of a broader response to stress. Whether the immunoproteasome is regulated by DNA stress, however, is not known. We here demonstrate that mitochondrial DNA stress upregulates the immunoproteasome and MHC class I antigen presentation pathway via cGAS/STING/type I interferon signaling resulting in cell autonomous activation of CD8+ T cells. The cGAS/STING-induced adaptive immune response is also observed in response to genomic DNA and is conserved in epithelial and mesenchymal cells of mice and men. In patients with idiopathic pulmonary fibrosis, chronic activation of the cGAS/STING-induced adaptive immune response in aberrant lung epithelial cells concurs with CD8+ T-cell activation in diseased lungs. Genetic depletion of the immunoproteasome and specific immunoproteasome inhibitors counteract DNA stress induced cytotoxic CD8+ T-cell activation. Our data thus unravel cytoplasmic DNA sensing via the cGAS/STING pathway as an activator of the immunoproteasome and CD8+ T cells. This represents a novel potential pathomechanism for pulmonary fibrosis that opens new therapeutic perspectives.

Unambiguous discrimination of all 20 proteinogenic amino acids and their modifications by nanopore.

Natural proteins are composed of 20 proteinogenic amino acids and their post-translational modifications (PTMs). However, due to the lack of a suitable nanopore sensor that can simultaneously discriminate between all 20 amino acids and their PTMs, direct sequencing of protein with nanopores has not yet been realized. Here, we present an engineered hetero-octameric Mycobacterium smegmatis porin A (MspA) nanopore containing a sole Ni2+ modification. It enables full discrimination of all 20 proteinogenic amino acids and 4 representative modified amino acids, Nω,N'ω-dimethyl-arginine (Me-R), O-acetyl-threonine (Ac-T), N4-(ß-N-acetyl-D-glucosaminyl)-asparagine (GlcNAc-N) and O-phosphoserine (P-S). Assisted by machine learning, an accuracy of 98.6% was achieved. Amino acid supplement tablets and peptidase-digested amino acids from peptides were also analyzed using this strategy. This capacity for simultaneous discrimination of all 20 proteinogenic amino acids and their PTMs suggests the potential to achieve protein sequencing using this nanopore-based strategy.

Brain cholesterol and Alzheimer's disease: challenges and opportunities in probe and drug development.

Cholesterol homeostasis is impaired in Alzheimer's disease; however, attempts to modulate brain cholesterol biology have not translated into tangible clinical benefits for patients to date. Several recent milestone developments have substantially improved our understanding of how excess neuronal cholesterol contributes to the pathophysiology of Alzheimer's disease. Indeed, neuronal cholesterol was linked to the formation of amyloid-ß and neurofibrillary tangles through molecular pathways that were recently delineated in mechanistic studies. Furthermore, remarkable advances in translational molecular imaging have now made it possible to probe cholesterol metabolism in the living human brain with PET, which is an important prerequisite for future clinical trials that target the brain cholesterol machinery in Alzheimer's disease patients-with the ultimate aim being to develop disease-modifying treatments. This work summarizes current concepts of how the biosynthesis, transport and clearance of brain cholesterol are affected in Alzheimer's disease. Further, current strategies to reverse these alterations by pharmacotherapy are critically discussed in the wake of emerging translational research tools that support the assessment of brain cholesterol biology not only in animal models but also in patients with Alzheimer's disease.

Intricate Ionic Behaviors in High-Performance Self-Powered Hydrothermal Chemical Generator Using Water and Iron (III) Gate.

Utilizing the ionic flux to generate voltage output has been confirmed as an effective way to meet the requirements of clean energy sources. Different from ionic thermoelectric (i-TE) and hydrovoltaic devices, a new hydrothermal chemical generator is designed by amorphous FeCl3 particles dispersing in MWCNT and unique ferric chloride or water gate. In the presence of gate, the special ion behaviors enable the cell to present a constant voltage of 0.60 V lasting for over 96 h without temperature difference. Combining the differences of cation concentration, humidity and temperature between the right and left side of sample, the maximum short-circuit current and power output can be obtained to 168.46 µA and 28.11 µW, respectively. The generator also can utilize the low-grade heat to produce electricity wherein Seebeck coefficient is 6.79 mV K-1 . The emerged hydrothermal chemical generator offers a novel approach to utilize the low-grade heat, water and salt solution resources, which provides a simple, sustainable and low-cost strategy to realize energy supply.

S2Snet: deep learning for low molecular weight RNA identification with nanopore.

Ribonucleic acid (RNA) is a pivotal nucleic acid that plays a crucial role in regulating many biological activities. Recently, one study utilized a machine learning algorithm to automatically classify RNA structural events generated by a Mycobacterium smegmatis porin A nanopore trap. Although it can achieve desirable classification results, compared with deep learning (DL) methods, this classic machine learning requires domain knowledge to manually extract features, which is sophisticated, labor-intensive and time-consuming. Meanwhile, the generated original RNA structural events are not strictly equal in length, which is incompatible with the input requirements of DL models. To alleviate this issue, we propose a sequence-to-sequence (S2S) module that transforms the unequal length sequence (UELS) to the equal length sequence. Furthermore, to automatically extract features from the RNA structural events, we propose a sequence-to-sequence neural network based on DL. In addition, we add an attention mechanism to capture vital information for classification, such as dwell time and blockage amplitude. Through quantitative and qualitative analysis, the experimental results have achieved about a 2% performance increase (accuracy) compared to the previous method. The proposed method can also be applied to other nanopore platforms, such as the famous Oxford nanopore. It is worth noting that the proposed method is not only aimed at pursuing state-of-the-art performance but also provides an overall idea to process nanopore data with UELS.

Peritoneal dialysis in an end-stage renal disease patient with massive ascites and primary liver cancer.

End-stage renal disease (ESRD) coexisted with cirrhosis, ascites, and primary liver cancer represents an extraordinarily rare clinical condition that typically occurs in very late-stage decompensated cirrhosis and is associated with an extremely poor prognosis. We present a case of a 68-year-old male patient with ESRD who experienced various decompensated complications of liver cirrhosis, particularly massive ascites and hepatic space-occupying lesions. Peritoneal dialysis (PD) catheter insertion and continuous ambulatory peritoneal dialysis (CAPD) treatment were successfully performed. During meticulous follow-up, the patient survived for one year but ultimately succumbed to complications related to liver cancer. PD can serve as an efficacious therapeutic approach for such late-stage patients afflicted together with severe cirrhosis, massive ascites and primary liver cancer.

One-pot synthesis of N-doped petroleum coke-based microporous carbon for high-performance CO2 adsorption and supercapacitors.

Waste resource utilization of petroleum coke is crucial for achieving global carbon emission reduction. Herein, a series of N-doped microporous carbons were fabricated from petroleum coke using a one-pot synthesis method. The as-prepared samples had a large specific surface area (up to 2512 m2/g), a moderate-high N content (up to 4.82 at.%), and high population (55%) of ultra-micropores (<0.7 nm). Regulating the N content and ultra-microporosity led to efficient CO2 adsorption and separation. At ambient pressure, the optimal N-doped petroleum coke-based microporous carbon exhibited the highest CO2 uptake of 4.25 mmol/g at 25°C and 6.57 mmol/g at 0°C. These values are comparable or even better than those of numerous previously reported adsorbents prepared by multistep synthesis, primarily due to the existence of ultra-micropores. The sample exhibited excellent CO2/N2 selectivity at 25°C owing to the abundant basic pyridinic and pyrrolic N species; and showed superior CO2 adsorption-desorption cycling performance, which was maintained at 97% after 10 cycles at 25°C. Moreover, petroleum coke-based microporous carbon, with a considerably high specific surface area and hierarchical pore structure, exhibited excellent electrochemical performance over the N-doped sample, maintaining a favorable specific capacitance of 233.25 F/g at 0.5 A/g in 6 mol/L KOH aqueous electrolyte. This study provides insight into the influence of N-doping on the porous properties of petroleum coke-based carbon. Furthermore, the as-prepared carbons were found to be promising adsorbents for CO2 adsorption, CO2/N2 separation and electrochemical application.

Discrimination of Disaccharide Isomers of Different Glycosidic Linkages Using a Modified MspA Nanopore.

Disaccharides are composed of two monosaccharide subunits joined by a glycosidic linkage in an α or ß configuration. Different combinations of isomeric monosaccharide subunits and different glycosidic linkages result in different isomeric disaccharide products. Thus, direct discrimination of these disaccharide isomers from a mixture is extremely difficult. In this paper, a hetero-octameric Mycobacterium smegmatis porin A (MspA) nanopore conjugated with a phenylboronic acid (PBA) adapter was applied for disaccharide sensing, with which three most widely known disaccharides in nature, including sucrose, lactose and maltose, were clearly discriminated. Besides, all six isomeric α-D-glucopyranosyl-D-fructoses, differing only in their glycosidic linkages, were also well resolved. Assisted by a custom machine learning algorithm, a 0.99 discrimination accuracy is achieved. Nanopore discrimination of disaccharide isomers with different glycosidic linkages, which has never been previously demonstrated, is inspiring for nanopore saccharide sequencing. This sensing capacity was also applied in direct identification of isomaltulose additives in a commercial sucrose-free yogurt, from which isomaltulose, lactose and L-lactic acid were simultaneously detected.

Deficiency of WTAP in islet beta cells results in beta cell failure and diabetes in mice.

AIMS/HYPOTHESIS: N6-methyladenosine (m6A) mRNA methylation and m6A-related proteins (methyltransferase-like 3 [METTL3], methyltransferase-like 14 [METTL14] and YTH domain containing 1 [YTHDC1]) have been shown to regulate islet beta cell function and the pathogenesis of diabetes. However, whether Wilms' tumour 1-associating protein (WTAP), a key regulator of the m6A RNA methyltransferase complex, regulates islet beta cell failure during pathogenesis of diabetes is largely unknown. The present study aimed to investigate the role of WTAP in the regulation of islet beta cell failure and diabetes. METHODS: Islet beta cell-specific Wtap-knockout and beta cell-specific Mettl3-overexpressing mice were generated for this study. Blood glucose, glucose tolerance, serum insulin, glucose-stimulated insulin secretion (both in vivo and in vitro), insulin levels, glucagon levels and beta cell apoptosis were examined. RNA-seq and MeRIP-seq were performed, and the data were well analysed. RESULTS: WTAP was downregulated in islet beta cells in type 2 diabetes, due to lipotoxicity and chronic inflammation, and islet beta cell-specific deletion of Wtap (Wtap-betaKO) induced beta cell failure and diabetes. Wtap-betaKO mice showed severe hyperglycaemia (above 20 mmol/l [360 mg/dl]) from 8 weeks of age onwards. Mechanistically, WTAP deficiency decreased m6A mRNA modification and reduced the expression of islet beta cell-specific transcription factors and insulin secretion-related genes by reducing METTL3 protein levels. Islet beta cell-specific overexpression of Mettl3 partially reversed the abnormalities observed in Wtap-betaKO mice. CONCLUSIONS/INTERPRETATION: WTAP plays a key role in maintaining beta cell function by regulating m6A mRNA modification depending on METTL3, and the downregulation of WTAP leads to beta cell failure and diabetes. DATA AVAILABILITY: The RNA-seq and MeRIP-seq datasets generated during the current study are available in the Gene Expression Omnibus database repository ( https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE215156 ; https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE215360 ).

The effect of dietary carbohydrate and calorie restriction on weight and metabolic health in overweight/obese individuals: a multi-center randomized controlled trial.

BACKGROUND: Both low-carbohydrate (LC) and calorie-restricted (CR) diets have been shown to have metabolic benefits. However, the two regimens have yet to be thoroughly compared. We conducted a 12-week randomized trial to compare the effects of these diets separately and in combination on both weight loss and metabolic risk factors in overweight/obese individuals. METHODS: A total of 302 participants were randomized to LC diet (n = 76), CR diet (n = 75), LC + CR diet (n = 76), or normal control (NC) diet (n = 75) using a computer-based random number generator. The primary outcome was the change in body mass index (BMI). The secondary outcomes included body weight, waist circumference, waist-to-hip ratio, body fat, and metabolic risk factors. All participants attended health education sessions during the trial. RESULTS: A total of 298 participants were analyzed. BMI change over 12 weeks was - 0.6 (95% CI, - 0.8 to - 0.3) kg/m2 in NC, - 1.3 (95% CI, - 1.5 to - 1.1) kg/m2 in CR, - 2.3 (95% CI, - 2.6 to - 2.1) kg/m2 in LC, and - 2.9 (95% CI, - 3.2 to - 2.6) kg/m2 in LC + CR. LC + CR diet was more effective than LC or CR diet alone at reducing BMI (P = 0.001 and P < 0.001, respectively). Furthermore, compared with the CR diet, the LC + CR diet and LC diet further reduced body weight, waist circumference, and body fat. Serum triglycerides were significantly reduced in the LC + CR diet group compared with the LC or CR diet alone. Plasma glucose, homeostasis model assessment of insulin resistance, and cholesterol concentrations (total, LDL, and HDL) did not change significantly between the groups during the 12-week intervention. CONCLUSIONS: The reduction of carbohydrate intake without restricting caloric intake is more potent to achieve weight loss over 12 weeks when compared to a calorie-restricted diet in overweight/obese adults. The combination of restricting carbohydrate and total calorie intake may augment the beneficial effects of reducing BMI, body weight, and metabolic risk factors among overweight/obese individuals. TRIAL REGISTRATION: The study was approved by the institutional review board of Zhujiang Hospital of Southern Medical University and registered at the China Clinical Trial Registration Center (registration number: ChiCTR1800015156).

Vascular Electrical Stimulation with Wireless, Battery-Free, and Fully Implantable Features Reduces Atherosclerotic Plaque Formation Through Sirt1-Mediated Autophagy.

Electrical stimulation (ES) is a safe and effective procedure in clinical rehabilitation with few adverse effects. However, studies on ES for atherosclerosis (AS) are scarce because ES does not provide a long-term intervention for chronic disease processes. Battery-free implants and surgically mounted them in the abdominal aorta of high-fat-fed Apolipoprotein E (ApoE-/- ) mice are used, which are electrically stimulated for four weeks using a wireless ES device to observe changes in atherosclerotic plaques. Results showed that there is almost no growth of atherosclerotic plaque at the stimulated site in AopE-/- mice after ES. RNA-sequencing (RNA-seq) analysis of Thp-1 macrophages reveal that the transcriptional activity of autophagy-related genes increase substantially after ES. Additionally, ES reduces lipid accumulation in macrophages by restoring ABCA1- and ABCG1-mediated cholesterol efflux. Mechanistically, it is demonstrated that ES reduced lipid accumulation through Sirtuin 1 (Sirt1)/Autophagy related 5 (Atg5) pathway-mediated autophagy. Furthermore, ES reverse autophagic dysfunction in macrophages of AopE-/- mouse plaques by restoring Sirt1, blunting P62 accumulation, and inhibiting the secretion of interleukin (IL)-6, resulting in the alleviation of atherosclerotic lesion formation. Here, a novel approach is shown in which ES can be used as a promising therapeutic strategy for AS treatment through Sirt1/Atg5 pathway-mediated autophagy.

Influence of spherical aberration on the tightly focusing characteristics of vector vortex beams.

For a tightly focusing imaging system, the aberration of the lens will result in a distorted focusing spot and undermine the system performance. In this paper, the expression of the tightly focused light field of Laguerre-Gaussian vector vortex beam (LGVVB) is deduced. Then the intensity distribution, focal shift and spot size that influenced by spherical aberration are calculated in detail. Since the vector vortex beams have multiple degrees of freedom to control the form of the intensity distribution on the focal plane, the effects of aberration on the focal spot are analyzed when some key parameters are changed. The results show the Pancharatnam topological charge is the most influential parameter to change the light distribution on the focal plane. According to the change rule, a scheme is proposed to minimize the effect of aberration by jointly adjusting the parameters of the LGVVB.

Minimizing early catheter failure using a risk stratification model for peritoneal dialysis.

BACKGROUND: Early catheter failure is the main reason for peritoneal dialysis (PD) failure, which often causes patients to withdraw from PD. Reducing the early catheter failure is critical to increase the acceptance of PD. The purpose of our study was to establish a risk stratification model to minimize early catheter failure. METHODS: A retrospective study with patients underwent PD catheter placement from January 2013 to March 2022 was conducted. The primary outcome event was early catheter failure. Univariate and multivariable logistic regression were performed to select potential risk predictors. A risk stratification model and a clinical procedure were established. The effectiveness of the model was evaluated by external validation. RESULTS: A total of 432 patients were finally enrolled in the study. The risk for early catheter failure was associated with younger age (odds ratio [OR], 0.930; 95% confidence interval [95% CI], 0.884 to 0.972; p = 0.002), lower body mass index (BMI) (OR, 0.797; 95% CI, 0.629 to 0.964; p = 0.036), and lower albumin (ALB) levels (OR, 0.881; 95% CI, 0.782 to 0.985; p = 0.036). The risk stratification model was established and performed great discrimination capability with AUC of 0.832 (cut-off value: 0.061, sensitivity: 0.853, specificity: 0.812). The model proved to be effective in external validation; the rate of early catheter failure was dropped off from 4.1% to 0%. CONCLUSIONS: We established an effective risk stratification model, by which patients with high risk of early catheter failure could be precisely identified. The clinical procedure based on the model was proved to be helpful to minimize early catheter failure.

Molecular interactions in short-chain perfluoroalkyl carboxylic acids and aqueous solutions.

The presence of short-chain per- and polyfluoroalkyl substances in water poses a major health and environmental challenge. Here, we have performed high-energy small- and wide-angle X-ray scattering measurements on CF3[CF2]nCOOH (where n = 1, 2, 3 represents the chain length) and their aqueous solutions at 10% mole concentrations to characterize their molecular interactions at the atomic and nanometer length scales. The experimental wide-angle structure factors have been modelled using Empirical Potential Structural Refinement. The oxygen-oxygen partial X-ray pair distribution functions show that the coordination number between the hydroxyl oxygen on the acid and surrounding oxygen water molecules increases significantly with acid chain length, rising from 3.2 for n = 1 to 4.1 for n = 3. The small-angle scattering is dominated by a sharp, high-intensity peak at Q1 ∼ 0.2 Å-1 and a smaller peak at Q2 = 1.2 Å-1 for n = 3, both of which decrease with decreasing chain length. The Q2 peak is attributed to groups of adjacent non-bonded acid molecules, and Q1 has contributions from both correlations between acid molecules and water-water interactions. In all cases, the models show nanoscale aggregation occurs in the form of denser channels of winding hydrogen-bonded chains, approximately 20 water molecules in length, surrounding clusters of acid molecules. This article is part of the theme issue 'Exploring the length scales, timescales and chemistry of challenging materials (Part 2)'.

Association between endothelin-1, nitric oxide, and Gensini score in chronic coronary syndrome.

BACKGROUND: Chronic coronary syndrome (CCS) is a major public health burden; its pathogenesis involves atherosclerosis and endothelial dysfunction. Endothelin-1 (ET-1) and nitric oxide (NO) are vasoactive substances synthesized by endothelial cells that play a crucial role in CCS development. The Gensini score (GS) is used for evaluating CCS severity based on lumen segment changes, stenosis degree, and coronary stenosis site. METHODS: This prospective study included 71 patients with CCS; we evaluated the relationships between GS and ET-1 and NO serum levels were evaluated in these patients. The GS was calculated for all patients. Serum ET-1 & NO levels among other laboratory parameters were measured. RESULTS: The high GS group had higher ET-1 and relatively NO expressions in the than the low GS group. GS was positively correlated with ET-1 and negatively correlated with NO, T4, and TSH levels. The results of the multiple linear regression analysis showed that ET-1 had the most significant effect on GS. CONCLUSIONS: We found a strong association between ET-1, NO, and CCS severity. A combination of ET-1, NO, and GS is an essential predictor of CCS disease severity.

Systematic pan-cancer analysis identified neuropilin 1 as an immunological and prognostic biomarker.

Neuropilin 1 (NRP1) is a transmembrane glycoprotein, nontyrosine kinase receptor that plays an important role in axonal growth and angiogenesis in the nervous system. Although currently more and more studies have shown that NRP1 plays an important role in some cancers, no systematic pan-cancer analysis of NRP-1 has been performed to date. Therefore, we aimed to investigate the associated immune function and prognostic value of NRP1 in 33 tumors of various cancer types. In this study, based on The Cancer Genome Atlas, Cancer Cell Line Encyclopedia, Genotype Tissue Expression, cBioportal for cancer genomics, and Human Protein Atlas (HPA databases), various bioinformatics analysis methods were used to investigate the potential carcinogenic effects of NRP1 activation, pan-cancer analysis of NRP1 expression, and the relationship between NRP1 expression and prognosis indicators including overall survival, disease-specific survival, disease-free interval, and progression-free interval, tumor mutational burden (TMB), and microsatellite instability (MSI). The results showed that NRP1 was highly expressed in most tumors. In addition, NRP1 was found to be positively or negatively correlated with the prognosis of different tumors. Also, the expression of NRP1 was associated with TMB and MSI in in 27 and 21 different types of tumors, respectively, and with DNA methylation in almost all the various types of tumors. The expression of the NRP1 gene was negatively correlated with the infiltration levels of most immune cells. In addition, the correlation between the level of immune cell infiltration and NRP1 expression varied according to immune cell subtype. Our study suggests that NRP1 plays an important role in tumor development and tumor immunity and could potentially be used as a prognostic indicator in a variety of malignancies.

Localization of sterols and oxysterols in mouse brain reveals distinct spatial cholesterol metabolism.

Dysregulated cholesterol metabolism is implicated in a number of neurological disorders. Many sterols, including cholesterol and its precursors and metabolites, are biologically active and important for proper brain function. However, spatial cholesterol metabolism in brain and the resulting sterol distributions are poorly defined. To better understand cholesterol metabolism in situ across the complex functional regions of brain, we have developed on-tissue enzyme-assisted derivatization in combination with microliquid extraction for surface analysis and liquid chromatography-mass spectrometry to locate sterols in tissue slices (10 µm) of mouse brain. The method provides sterolomic analysis at 400-µm spot diameter with a limit of quantification of 0.01 ng/mm2 It overcomes the limitations of previous mass spectrometry imaging techniques in analysis of low-abundance and difficult-to-ionize sterol molecules, allowing isomer differentiation and structure identification. Here we demonstrate the spatial distribution and quantification of multiple sterols involved in cholesterol metabolic pathways in wild-type and cholesterol 24S-hydroxylase knockout mouse brain. The technology described provides a powerful tool for future studies of spatial cholesterol metabolism in healthy and diseased tissues.

Cholesterol 25-hydroxylase suppresses SARS-CoV-2 replication by blocking membrane fusion.

Cholesterol 25-hydroxylase (CH25H) is an interferon (IFN)-stimulated gene that shows broad antiviral activities against a wide range of enveloped viruses. Here, using an IFN-stimulated gene screen against vesicular stomatitis virus (VSV)-SARS-CoV and VSV-SARS-CoV-2 chimeric viruses, we identified CH25H and its enzymatic product 25-hydroxycholesterol (25HC) as potent inhibitors of SARS-CoV-2 replication. Internalized 25HC accumulates in the late endosomes and potentially restricts SARS-CoV-2 spike protein catalyzed membrane fusion via blockade of cholesterol export. Our results highlight one of the possible antiviral mechanisms of 25HC and provide the molecular basis for its therapeutic development.

Discrimination between Different DNA Lesions by Monitoring Single-Molecule Polymerase Stalling Kinetics during Nanopore Sequencing.

O6-Carboxymethylguanosine (O6-CMG), O6-methylguanosine (O6-MeG), and abasic site (AP site) are DNA lesions induced by alkylating agents. Identification of these lesions in DNA may aid in understanding their relevance to carcinogenesis and may be used for diagnosis. Nanopore sequencing (NPS) may directly report nucleotide modifications solely from the nanopore readout. However, the conventional NPS strategy still suffers from interferences from neighboring sequences. Instead, by observation of the enzymatic stalling kinetics caused by the O6-CMG, O6-MeG, or AP site, discrimination between different DNA lesions is directly achieved. This strategy is not interfered with by the sequence context around the lesion. The lesion, which retards the movement of the DNA through the pore, efficiently prohibits misreading of the DNA lesion. These results suggest a new strategy in the identification of DNA lesions or DNA modifications. It also provides a high-resolution biophysical tool to investigate enzymatic kinetics caused by DNA lesions and the corresponding enzymes.

Hypoxia Increases ATX Expression by Histone Crotonylation in a HIF-2α-Dependent Manner.

Autotaxin (ATX), the key enzyme that generates lysophosphatidic acid (LPA) from lysophosphatidylcholine (LPC), is involved in tumorigenesis through the ATX-LPA axis and is regarded as a valuable target in tumor therapy. Hypoxia is a major feature of solid tumors and contributes to tumor development with striking alterations in the gene expression profile. Here, we show that hypoxia induces ATX expression in a hypoxia-inducible factor (HIF) 2α-dependent fashion in human colon cancer SW480 cells. HIF-2α is directly bound to specific hypoxia response elements (HREs) in the ATX promoter. Under hypoxic conditions, knockout or inhibition of ATX suppressed the migration of SW480 cells, which could be rescued by the addition of LPA, suggesting that the induction of ATX during hypoxia promotes cancer cell migration through the ATX-LPA axis. Further studies showed that ATX expression was induced by HIF-2α through recruiting p300/CBP, which led to crotonylation but not acetylation of histone H3 in the ATX promoter region during hypoxia. Moreover, elevation of cellular histone crotonylation levels could induce ATX expression under normoxic conditions. In conclusion, our findings reveal that ATX is induced in SW480 cells during hypoxia by histone crotonylation in a HIF-2α-dependent manner, while as a novel mechanism of ATX expression regulation, the upregulation of ATX expression by histone crotonylation is not confined to hypoxia.