A modified dual-knife fistulotomy for achieving challenging biliary cannulation in type 3 papilla.

Video 1A modified dual-knife fistulotomy for achieving challenging biliary cannulation in type 3 papilla.

Development of cyclopeptide inhibitors of cGAS targeting protein-DNA interaction and phase separation.

Cyclic GMP-AMP synthase (cGAS) is an essential sensor of aberrant cytosolic DNA for initiating innate immunity upon invading pathogens and cellular stress, which is considered as a potential drug target for autoimmune and autoinflammatory diseases. Here, we report the discovery of a class of cyclopeptide inhibitors of cGAS identified by an in vitro screening assay from a focused library of cyclic peptides. These cyclopeptides specifically bind to the DNA binding site of cGAS and block the binding of dsDNA with cGAS, subsequently inhibit dsDNA-induced liquid phase condensation and activation of cGAS. The specificity and potency of one optimal lead XQ2B were characterized in cellular assays. Concordantly, XQ2B inhibited herpes simplex virus-1 (HSV-1)-induced antiviral immune responses and enhanced HSV-1 infection in vitro and in vivo. Furthermore, XQ2B significantly suppressed the elevated levels of type I interferon and proinflammatory cytokines in primary macrophages from Trex1-/- mice and systemic inflammation in Trex1-/- mice. XQ2B represents the specific cGAS inhibitor targeting protein-DNA interaction and phase separation and serves as a scaffold for the development of therapies in the treatment of cGAS-dependent inflammatory diseases.

Identification and contribution of potential sources to atmospheric lead pollution in a typical megacity: Insights from isotope analysis and the Bayesian mixing model.

Atmospheric particulate matter (PM) enriched with lead (Pb) has severe irreversible effects on human health. Therefore, identifying the contribution of Pb emission sources is essential for protecting the health of residents. Using the Pb isotopic tracer method, this study explored the seasonal characteristics and primary anthropogenic Pb sources for atmospheric PM in Tianjin in 2019. We calculated the contribution of Pb sources using the end-member and MixSIAR models. The results showed that Pb loaded in PM10 was more abundant in January than in July, and was strongly influenced by meteorological conditions and anthropogenic emissions. The primary Pb sources of the aerosol samples originated from coal combustion and vehicle and steel plant emissions, mainly originating from local Pb emission sources in Tianjin. The PM10-bond Pb in January was influenced by regional transportation and local sources. The MixSIAS model calculated the contribution of coal combustion as approximately 50 %. Compared with that in January, the contribution of coal combustion decreased by 9.6 % in July. Our results indicate that some of the benefits of phased-out leaded gasoline have been short-lived, whereas other industrial activities releasing Pb have increased. Furthermore, the results emphasise the practicability of the Pb isotope tracer source approach for identifying and distinguishing between different anthropogenic Pb inputs. Based on this study, scientific and effective air pollution prevention and control programs can be formulated to provide decision support for the guidance and control of air pollutant emissions.

Development of a novel anti-inflammatory recombinant uricase with extended half-life for gout therapy.

Gout is a form of inflammatory arthritis that results from elevated serum uric acid levels and the deposition of urate crystals in multiple joints. The inflammatory response during an acute gout attack is mediated by the activation of the NLRP3 inflammasome, leading to the release of IL-1ß and inducing a localized tissue inflammatory response. Urate lowering therapies such as Pegloticase effectively reduce serum uric acid levels but are generally associated with an increase in acute gout flares. In this study, we developed a long-acting anti-inflammatory recombinant uricase by sequential fusing interleukin-1 receptor antagonist (IL-1Ra) and albumin-binding domain (ABD) with the N-terminal end of Arthrobacter globiformis uricase (AgUox). The recombinant uricase has longer in vivo half-life, and significantly alleviates monosodium urate (MSU) crystals induced inflammation in mouse model compared with the wild-type AgUox. This long-acting anti-inflammatory recombinant uricase has the potential to be developed as an effective urate lowering therapy with better safety profiles.

Using Stable Sulfur Isotope to Trace Sulfur Oxidation Pathways during the Winter of 2017-2019 in Tianjin, North China.

After the implementation of the Coal Replacing Project (CRP) in the northern parts of China in 2017, its effect on PM2.5 composition is still unclear. In the study, water-soluble ionic components (WSICs) and stable sulfur isotope ratios (δ34S) of SO42- in PM2.5 collected during the domestic heating period before and after the implementation of CRP in Tianjin were analyzed. Results showed that the average concentrations of both PM2.5 and WSICs have dropped dramatically after the CRP, especially for the SO42- (by approximately 57-60%). After the CRP, the range of δ34Ssulfate was significantly narrowed to 4.1-7.5‱ in January 2018 and 1.4-6.1‱ in January 2019, which suggested that the sulfur source was becoming simple. It was interesting that the δ34Ssulfate value in the pollution period before the CRP was higher than that in the clean period, whereas it showed the opposite tendency after the CRP, which implied that the contribution of sea salt was high during the pollution period before the CRP. The MIXSIAR model calculated that the contributions of the transition-metal ion (TMI) oxidation and NO2 oxidation pathways in the three sampling stages were higher than those of the OH radical oxidation and H2O2/O3 oxidation pathways, indicating that the formation pathway of sulfate was mainly dominated by heterogeneous oxidation. Before the CRP, the NO2 oxidation pathway was the dominant sulfate oxidation pathway during a haze episode, and the TMI oxidation pathway dominated the formation of sulfates after the CRP.

N-cystaminylbiguanide MC001 prevents neuron cell death and alleviates motor deficits in the MPTP-model of Parkinson's disease.

Parkinson's disease (PD) is a common neurodegenerative disease characterized by the progressive loss of dopaminergic (DA) neurons in the substantia nigra (SN), which is highly associated with oxidative stress. Antioxidants are therefore considered as potential therapies in PD treatment. In this study, we examined the neuroprotective effect of a cysteamine-based biguanide N-cystaminylbiguanide (MC001) in the MPTP mouse model of PD. The results showed that MC001 prevented neuron cell death and alleviated motor deficits in the MPTP mouse model of PD. Both in vitro and in vivo data indicated that MC001 may exert its neuroprotective effect by alleviating ROS production, suppressing neuroinflammation, and upregulating BDNF expression. Further mechanistic studies revealed that MC001 promoted GSH synthesis by inducing the expression of Glutamate-cysteine ligase catalytic subunit (Gclc) and enhancing the activity of Glutamate-cysteine ligase (Gcl). Our results suggest that MC001 warrants further investigation as a potential candidate for the treatment of PD.

Identification of DNA aptamers that specifically targets EBV+ nasopharyngeal carcinoma via binding with EphA2/CD98hc complex.

Nasopharyngeal carcinoma (NPC) is one of the Epstein-Barr virus (EBV)-associated malignancies and has a distinct geographical distribution. The high mortality rates of NPC patients with advanced and recurrent disease highlight the urgent need for biomarkers for early diagnosis and effective treatments. In this study, we developed DNA aptamers that specifically bind to EBV positive NPC cells by the Cell-SELEX procedure. We further identified the EphA2 (ephrin type-A receptor 2)/CD98hc (CD98 heavy chain) complex as the potential target of the aptamer EA-3 by combining aptamer-based separation and mass spectrometry analysis. Our results revealed for the first time that EphA2 colocalized with CD98hc at the plasma membrane and EphA2 coimmunoprecipitated with CD98hc, which may serve as a starting point for exploring the potential functions of the complex of EphA2 and CD98hc in NPCs. Here, we demonstrated that aptamers can be useful for the identification of protein complexes on the surface of cancer cells.

Biguanide MC001, a Dual Inhibitor of OXPHOS and Glycolysis, Shows Enhanced Antitumor Activity Without Increasing Lactate Production.

Metformin and other biguanides represent a new class of inhibitors of mitochondrial complex I that show promising antitumor effects. However, stronger inhibition of mitochondrial complex I is generally associated with upregulation of glycolysis and higher risk of lactic acidosis. Herein we report a novel biguanide derivative, N-cystaminylbiguanide (MC001), which was found to inhibit mitochondrial complex I with higher potency while inducing lactate production to a similar degree as metformin.Furthermore, MC001 was found to efficiently inhibit a panel of colorectal cancer (CRC) cells in vitro and to suppress tumor growth in a HCT116 xenograft nude mouse model, while not enhancing lactate production relative to metformin, exhibiting a superior safety profile to other potent biguanides such as phenformin. Mechanistically, MC001 efficiently inhibits mitochondrial complex I, activates AMPK, and represses mTOR, leading to cell-cycle arrest and apoptosis. Notably, MC001 inhibits both oxidative phosphorylation (OXPHOS) and glycolysis. We therefore propose that MC001 warrants further investigation in cancer treatment.

Varying water column stability controls the denitrification process in a subtropical reservoir, Southwest China.

Reservoirs are regarded as hotspots of nitrogen transformation and potential sources of nitrous oxide (N2O). However, it remains unclear how the hydrological conditions due to dam construction control the processes of nitrogen transformation in reservoir waters. To address this issue, we examined the spatial-temporal characteristics of nitrate concentrations, δ15N-NO3-, δ18O-NO3-, δ18O-H2O, relative water column stability (RWCS), and related environmental factors in a subtropical eutrophic reservoir (Hongfeng Reservoir, HFR), Southwest China. We found that denitrification was the most important nitrogen transformation process in the HFR and that higher denitrification intensity was associated with increased RWCS in summer, which suggested hydrological control of the denitrification process. In contrast, low RWCS conditions favored the nitrification process in the HFR in winter. Additionally, dissolved oxygen (DO; p < 0.05) and nitrate concentrations (p < 0.01) had significant impacts on the denitrification rate. We also found that the spatiotemporal RWCS variations were a prerequisite for regulating DO/nitrate stratification and the coupling/decoupling of nitrification-denitrification at the local and global scales. This study would advances our knowledge of the impacts of RWCS and thermal stratification on nitrogen transformation processes in reservoirs.

Targeting Extracellular Cyclophilin A via an Albumin-Binding Cyclosporine A Analogue.

An albumin-binding CsA analogue 4MCsA was achieved by attachment of a thiol-reactive maleimide group at the side-chain of P4 position of CsA derivative. 4MCsA was semi-synthesized from CsA, and the cell-impermeability of albumin-4MCsA was detected by mass spectrometry and a competitive flow cytometry. 4MCsA exhibits inhibition of chemotaxis activity and inflammation by targeting extracellular CypA without immunosuppressive effect and cellular toxicity. These combined results suggested that 4MCsA can be restricted extracellularly through covalently binding to Cys34 of albumin with its maleimide group, and regulate the functions of cyclophilin A extracellularly.

Insight into the mechanisms of denitrification and sulfate reduction coexistence in cascade reservoirs of the Jialing River: Evidence from a multi-isotope approach.

The coexistence of denitrification and bacterial sulfate reduction (BSR) processes is commonly observed in natural water systems. However, its formation mechanism remains unclear at a basin scale due to the difficulty of precise identification of these processes. To address this issue, we investigated the spatial-temporal variations in water chemistry and isotopic compositions (e.g., δ13CDIC, δ15NNO3, δ18ONO3, δ34SSO4, and δ18OSO4) in cascade reservoirs (artificial dam lakes) of the Jialing River, SW China in 2016. The results showed that the denitrification and BSR processes coexisted in the studied reservoirs, which was supported by the positive correlation between δ15NNO3 and δ18ONO3 and between δ34SSO4 and δ18OSO4, and by the decreasing concentrations of NO3- and SO42-. Moreover, covariation of Δ13CDIC, Δ15NNO3, and Δ34SSO4 indicated the dominance of heterotrophic denitrification (HD) in the reservoir waters along with the occurrence of bacterial sulfide oxidation (BSO). In addition to SO42- and NO3-, the coexistence of HD and BSR processes were also controlled by the dissolved organic carbon (DOC) in winter and dissolved oxygen (DO) contents in other seasons. Overall, the cumulative effect of cascade reservoirs caused δ15NNO3 and δ34SSO4 to display an upward trend from upstream to downstream in the Jialing River, while δ13CDIC showed an opposite downward trend, which implying that cascade reservoirs may be in favor of the coexistence of the HD and BSR processes. This study therefore concludes that the multi-isotope approach could be a useful technique to ascertain the coexistence mechanism of HD and BSR processes in reservoir water systems.

Impact of Coal Replacing Project on atmospheric fine aerosol nitrate loading and formation pathways in urban Tianjin: Insights from chemical composition and 15N and 18O isotope ratios.

The 'Coal Replacing Project' (CRP), replacing coal with cleaner energy like natural gas and electricity, was implemented in North China to curb PM2.5 pollution; therefore, it is important to explore the sources and transformation mechanisms of PM2.5 nitrate under this strategy for examining its effectiveness. In this study, daytime and nighttime PM2.5 samples of one summer (Jul-2016, C1) and two winters (Jan-2017, C2 and Jan-2018, C3, before and during the CRP, respectively) were collected in urban Tianjin. Concentrations of PM2.5 and water-soluble inorganic ions were analyzed, and δ15N and δ18O were used to calculate the contributions of different NOX sources to nitrate based on a Bayesian mixing model. The results showed that the average concentrations of PM2.5 and its dominant inorganic ions (SO42-, NO3-, NH4+) in C3 during the CRP, compared to C2, decreased by 62.13%, 79.69%, 55.14% and 38.84%, respectively, attesting the improvement of air quality during the CRP. According to the correlation between [NO3-/SO42-] and [NH4+/SO42-] as well as δ18O variations, the homogeneous formation pathway might be dominant in C1, while the heterogeneous pathway would be primary in C2 and C3 during the formation of nitrate. Moreover, the heterogeneous pathway contributed more in C3 than in C2. The dominant sources in C1 were biogenic soil emission (37.0% ±â€¯9.9%) and mobile emission (25.7% ±â€¯19.1%), while coal combustion (42.4% ±â€¯13.8% in C2 and 34.9% ±â€¯14.4% in C3) and biomass burning (31.0% ±â€¯21.2% and 34.7% ±â€¯22.7%) were the main sources in C2 and C3. In the winter, the contribution of coal combustion dropped by about 8% during the CRP (C3) in comparison with that in C2, suggesting the implementation of CRP played an important role in reducing NOX from coal combustion.

STAT3 inhibition enhances CDN-induced STING signaling and antitumor immunity.

Cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway is a key regulator in innate immunity and has emerged as a promising drug target in cancer treatment, but the utility of this pathway in therapeutic development is complicated by its dichotomous roles in tumor development and immunity. The activation of the STING pathway and the induced antitumor immunity could be attenuated by the feedback activation of IL-6/STAT3 pathway. Here we reported that STAT3 inhibition significantly enhanced the intensity and duration of STING signaling induced by the STING agonist c-diAM(PS)2. Such sensitization effect of STAT3 inhibition on STING signaling depended on STING rather than cGAS, which was mediated by simultaneously upregulating the positive modulators and downregulating the negative modulators of the STING pathway. Furthermore, the combination treatment with the STAT3 inhibitor and STING agonist markedly regressed tumor growth in syngeneic mice by increasing CD8+ T cells and reducing regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs) in the tumor microenvironment. Our work provides a rationale for the combination of STAT3 inhibitors and STING agonists in cancer immunotherapy.

Structural basis for dimerization of the death effector domain of the F122A mutant of Caspase-8.

Caspase-8 is an apoptotic protease that is activated by a proximity-induced dimerization mechanism within the death-inducing signaling complex (DISC). The death effector domain (DED) of caspase-8 is involved in protein-protein interactions and is essential for the activation. Here, we report two crystal structures of the dimeric DEDs of the F122A mutant of caspase-8, both of which illustrate a novel domain-swapped dimerization, while differ in the relative orientation of the two subunits and the solvent exposure of the conserved hydrophobic patch Phe122/Leu123. We demonstrate that mutations disrupting the dimerization of the DEDs abrogate the formation of cellular death effector filaments (DEFs) and the induced apoptosis by overexpressed DEDs. Furthermore, such dimerization-disrupting mutations also impair the activation of the full-length caspase-8 and the downstream apoptosis cascade. The structures provide new insights into understanding the mechanism underlying the activation of procaspase-8 within the DISC and DEFs.

Identification of α-Mangostin as an Agonist of Human STING.

The xanthone derivate 5',6'-dimethylxanthenone-4-acetic acid (DMXAA, also known as ASA404 or vadimezan) is a potent agonist of murine STING (stimulator of interferon genes), but cannot activate human STING. Herein we report that α-mangostin, which bears the xanthone skeleton, is an agonist of human STING, but activates murine STING to a lesser extent. Biochemical and cell-based assays indicate that α-mangostin binds to and activates human STING, leading to activation of the downstream interferon regulatory factor (IRF) pathway and production of type I interferons. Furthermore, our studies show that α-mangostin has the potential to repolarize human monocyte-derived M2 macrophages to the M1 phenotype. The agonist effect of α-mangostin in the STING pathway might account for its antitumor and antiviral activities.

Regulation of endothelial intracellular adenosine via adenosine kinase epigenetically modulates vascular inflammation.

The molecular mechanisms underlying vascular inflammation and associated inflammatory vascular diseases are not well defined. Here we show that endothelial intracellular adenosine and its key regulator adenosine kinase (ADK) play important roles in vascular inflammation. Pro-inflammatory stimuli lead to endothelial inflammation by increasing endothelial ADK expression, reducing the level of intracellular adenosine in endothelial cells, and activating the transmethylation pathway through increasing the association of ADK with S-adenosylhomocysteine (SAH) hydrolase (SAHH). Increasing intracellular adenosine by genetic ADK knockdown or exogenous adenosine reduces activation of the transmethylation pathway and attenuates the endothelial inflammatory response. In addition, loss of endothelial ADK in mice leads to reduced atherosclerosis and affords protection against ischemia/reperfusion injury of the cerebral cortex. Taken together, these results demonstrate that intracellular adenosine, which is controlled by the key molecular regulator ADK, influences endothelial inflammation and vascular inflammatory diseases.The molecular mechanisms underlying vascular inflammation are unclear. Here the authors show that pro-inflammatory stimuli lead to endothelial inflammation by increasing adenosine kinase expression, and that its knockdown in endothelial cells inhibits atherosclerosis and cerebral ischemic injury in mice.

Endothelial adenosine A2a receptor-mediated glycolysis is essential for pathological retinal angiogenesis.

Adenosine/adenosine receptor-mediated signaling has been implicated in the development of various ischemic diseases, including ischemic retinopathies. Here, we show that the adenosine A2a receptor (ADORA2A) promotes hypoxia-inducible transcription factor-1 (HIF-1)-dependent endothelial cell glycolysis, which is crucial for pathological angiogenesis in proliferative retinopathies. Adora2a expression is markedly increased in the retina of mice with oxygen-induced retinopathy (OIR). Endothelial cell-specific, but not macrophage-specific Adora2a deletion decreases key glycolytic enzymes and reduces pathological neovascularization in the OIR mice. In human primary retinal microvascular endothelial cells, hypoxia induces the expression of ADORA2A by activating HIF-2α. ADORA2A knockdown decreases hypoxia-induced glycolytic enzyme expression, glycolytic flux, and endothelial cell proliferation, sprouting and tubule formation. Mechanistically, ADORA2A activation promotes the transcriptional induction of glycolytic enzymes via ERK- and Akt-dependent translational activation of HIF-1α protein. Taken together, these findings advance translation of ADORA2A as a therapeutic target in the treatment of proliferative retinopathies and other diseases dependent on pathological angiogenesis.Pathological angiogenesis in the retina is a major cause of blindness. Here the authors show that adenosine receptor A2A drives pathological angiogenesis in the oxygen-induced retinopathy mouse model by promoting glycolysis in endothelial cells via the ERK/Akt/HIF-1α pathway, thereby suggesting new therapeutic targets for disease treatment.