Sintilimab-induced severe erosive hemorrhagic gastritis and pyloric obstruction: a case report and literature review.

Immune checkpoint inhibitors could restore immune surveillance to attack tumor through targeting CTLA-4, PD-1 or PD-L1, and have achieved huge success. However, immune-related adverse events (irAEs) have been attracting attention as their application is expanding. Gastritis is relatively rare as a subtype of irAEs, particularly severe gastritis. Guidelines on its clinical management still remain undefined due to limited data. Sintilimab is a PD-1 inhibitor approved in China. Here we offer a case of sintilimab-induced severe erosive hemorrhagic gastritis and pyloric obstruction. Conventional proton pump inhibitors and mucosal protective agents did not take effect, so glucocorticoid was chosen. This severe gastritis was successfully cured finally. Our report describing its clinical performances, endoscopic characteristics and treatments, could assist clinicians to better know this rare irAE.

Immune checkpoint inhibitors are a type of drug which fight cancer through enhancing the body's immunity. They have significant anti-tumor effects. The side effects of these medications, called immune-related adverse events (irAEs), are becoming more obvious as more and more patients undergo immunotherapy. Sintilimab is an immune checkpoint inhibitor approved in China. This case report discusses an irAE in a patient treated with sintilimab. The patient suffered from gastritis, with severely erosive bloody inflammation and a narrow outflow tract of the stomach. Inhibiting stomach acid and protecting mucosa are classical methods to treat gastritis, but neither worked in this case. However, the patient was successfully treated with glucocorticoids, a type of steroid used to treat inflammation. Gastritis is an uncommon irAE for patients treated with immune checkpoint inhibitors and we are short of credible instructions to timely recognize and manage it. This case report might be valuable for other clinicians looking to treat patients with similar symptoms.

Synthesis of gem-Difluorinated Isoxazoles via Palladium-Catalyzed Oxylallylation of Alkynone Oxime Ethers.

A novel and reliable palladium-catalyzed oxylallylation of alkynone oxime ethers with fluorine-containing alkenes was accomplished. Using the bulk industrial chemical 3-bromo-3,3-difluoroprop-1-ene as the coupling partner, this synthetic methodology offers the first example for the assembly of structurally diverse gem-difluorinated isoxazole derivatives in moderate to good yields with high atom- and step-economy and excellent functional group compatibility. More importantly, this strategy allows for the direct combination of the isoxazole motifs and gem-difluoroalkene unit, which is not easy to obtain through a general synthetic strategy.

S1PR1 attenuates pulmonary fibrosis by inhibiting EndMT and improving endothelial barrier function.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a chronic fatal disease of unknown etiology. Its pathological manifestations include excessive proliferation and activation of fibroblasts and deposition of extracellular matrix. Endothelial cell-mesenchymal transformation (EndMT), a novel mechanism that generates fibroblast during IPF, is responsible for fibroblast-like phenotypic changes and activation of fibroblasts into hypersecretory cells. However, the exact mechanism behind EndMT-derived fibroblasts and activation is uncertain. Here, we investigated the role of sphingosine 1-phosphate receptor 1 (S1PR1) in EndMT-driven pulmonary fibrosis. METHODS: We treated C57BL/6 mice with bleomycin (BLM) in vivo and pulmonary microvascular endothelial cells with TGF-ß1 in vitro. Western blot, flow cytometry, and immunofluorescence were used to detect the expression of S1PR1 in endothelial cells. To evaluate the effect of S1PR1 on EndMT and endothelial barrier and its role in lung fibrosis and related signaling pathways, S1PR1 agonist and antagonist were used in vitro and in vivo. RESULTS: Endothelial S1PR1 protein expression was downregulated in both in vitro and in vivo models of pulmonary fibrosis induced by TGF-ß1 and BLM, respectively. Downregulation of S1PR1 resulted in EndMT, indicated by decreased expression of endothelial markers CD31 and VE-cadherin, increased expression of mesenchymal markers α-SMA and nuclear transcription factor Snail, and disruption of the endothelial barrier. Further mechanistic studies found that stimulation of S1PR1 inhibited TGF-ß1-mediated activation of the Smad2/3 and RhoA/ROCK1 pathways. Moreover, stimulation of S1PR1 attenuated Smad2/3 and RhoA/ROCK1 pathway-mediated damage to endothelial barrier function. CONCLUSIONS: Endothelial S1PR1 provides protection against pulmonary fibrosis by inhibiting EndMT and attenuating endothelial barrier damage. Accordingly, S1PR1 may be a potential therapeutic target in progressive IPF.

Palladium-Catalyzed Reductive Formylation of Aryl Iodides with CO2 under Mild Conditions.

A palladium-catalyzed reductive formylation of aryl iodides with carbon dioxide as the carbonyl source under mild reaction conditions was realized by using a combination of Pd(PCy3)2Cl2 and di-2-pyridyl ketone as the catalyst and phenylsilane as the reductive reagent, leading to a variety of aromatic aldehydes in moderate to excellent yields. The protocol features wide substrate scope, good functional group tolerance, and simple operation.

Palladium-Catalyzed Carbonylation of Aryl Bromides with Carbon Dioxide To Access Aryl Carboxylic Acids under Mild Conditions.

A palladium-catalyzed direct carbonylation of aryl bromides with carbon dioxide as the carbonyl source has been developed by using Pd(dba)2/DPEPhos as the catalyst under mild reaction conditions, providing an efficient route to a variety of aryl carboxylic acids in moderate to high yields. The methods have many advantages such as the use of a simple palladium catalyst system, wide substrate scope, good functional group tolerance, high yields, and easy scalability.

Facile synthesis of isoquinolines and isoquinoline N-oxides via a copper-catalyzed intramolecular cyclization in water.

A highly efficient method for the facile access of isoquinolines and isoquinoline N-oxides via a Cu(i)-catalyzed intramolecular cyclization of (E)-2-alkynylaryl oxime derivatives in water has been developed. This protocol was performed under simple and mild conditions without organic solvent, additives or ligands. By switching on/off a hydroxyl protecting group of oximes, the selective N-O/O-H cleavage could be triggered, delivering a series of isoquinolines and isoquinoline N-oxides, respectively, in moderate to high yields with good functional group tolerance and high atom economy. Moreover, the practicality of this method was further demonstrated by the total synthesis of moxaverine in five steps.

Palladium-catalyzed oxidative Heck reaction of non-activated alkenes directed by fluorinated alcohol.

A novel, Pd-catalyzed oxidative Heck reaction of non-activated alkenes synergistically directed by bifunctional groups has been developed firstly by using O2 as a green oxidant, yielding the oxidative Heck products with excellent yields in a regio- and stereoselective manner. This bifunctional synergistic activation mechanism was demonstrated by experimental analysis and detailed computational studies, wherein the hydroxyl group directs the migratory insertion of the alkenes and the trifluoromethyl group facilitates the subsequent ß-H elimination and reductive elimination. Moreover, a pesticidal active compound was synthesized using the bifunctional synergistically directed C-H arylation as the key step, which demonstrated its synthetic utility.

Glucolipotoxicity induces endothelial cell dysfunction by activating autophagy and inhibiting autophagic flow.

OBJECTIVES: This study aims to determine the role and mechanism of autophagy in endothelial cell dysfunction by glucolipotoxicity. METHODS: Human umbilical vein endothelial cells (HUVECs) were treated with high glucose and high palmitic acid. The number of autophagosomes was evaluated by monodansylcadaverine (MDC) staining and transmission electron microscopy (TEM). The expression of autophagy-related proteins (LC3 and P62) was assessed by Western blotting. Capillary tube-like formation was evaluated on Matrigel. Reactive oxygen species (ROS) production was detected by DCFH-DA. Cell apoptosis was measured by Hoechst 33258 staining and flow cytometry. Phosphorylation of AMPK, mTOR, and ULK1 was also analyzed by Western blotting. RESULTS: We found that glucolipotoxicity induced autophagy initiation and hindered autophagosomes degradation. Moreover, glucolipotoxicity increased the production of intracellular ROS, decreased the ability of tubular formation, and increased cell apoptosis. However, endothelial cell dysfunction was alleviated by 3-methyladenine, an early-stage autophagy inhibitor. Additionally, glucolipotoxicity promoted the phosphorylation of AMPK and ULK1 and inhibited the phosphorylation of mTOR. CONCLUSIONS: Glucolipotoxicity initiates autophagy through the AMPK/mTOR/ULK1 signaling pathway and inhibits autophagic flow, leading to the accumulation of autophagosomes, thereby inducing apoptosis and impairing endothelial cell function.

Niobium carbide (MXene) reduces UHMWPE particle-induced osteolysis.

Joint replacement surgery is one of the orthopedic surgeries with high successful rates; however, wear debris generated from prostheses can ultimately lead to periprosthetic osteolysis and failure of the implant. The implant-derived particulate debris such as ultrahigh molecular weight polyethylene (UHMWPE) can initiate the local immune response and recruit monocytic cells to phagocytose particles for generating reactive oxygen species (ROS). ROS induces osteoclastogenesis and macrophages to secrete cytokines which ultimately promote the development of osteolysis. In this work, we develop the few-layered Nb2C (FNC) as an antioxidant which possesses the feature of decreasing the production of cytokines and inhibiting osteoclastogenesis by its ROS adsorption. Moreover, local injection of FNC attenuates the UHMWPE-induced osteolysis in a mouse calvarial model. In sum, our results suggest that FNC can be used for treating osteolytic bone disease caused by excessive osteoclastogenesis.

Stereodivergent synthesis of ß-iodoenol carbamates with CO2 via photocatalysis.

Photocatalytic conversion of carbon dioxide (CO2) into value-added chemicals is of great significance from the viewpoint of green chemistry and sustainable development. Here, we report a stereodivergent synthesis of ß-iodoenol carbamates through a photocatalytic three-component coupling of ethynylbenziodoxolones, CO2 and amines. By choosing appropriate photocatalysts, both Z- and E-isomers of ß-iodoenol carbamates, which are difficult to prepare using existing methods, can be obtained stereoselectively. This transformation featured mild conditions, excellent functional group compatibility and broad substrate scope. The potential synthetic utility of this protocol was demonstrated by late-stage modification of bioactive molecules and pharmaceuticals as well as by elaborating the products to access a wide range of valuable compounds. More importantly, this strategy could provide a general and practical method for stereodivergent construction of trisubstituted alkenes such as triarylalkenes, which represents a fascinating challenge in the field of organic chemistry research. A series of mechanism investigations revealed that the transformation might proceed through a charge-transfer complex which might be formed through a halogen bond.

Metformin alleviates inflammation through suppressing FASN-dependent palmitoylation of Akt.

Metformin, traditionally regarded as a hypoglycemic drug, has been studied in other various fields including inflammation. The specific mechanism of metformin's effect on immune cells remains unclear. Herein, it is verified that LPS-induced macrophages are characterized by enhanced endogenous fatty acid synthesis and the inhibition of fatty acid synthase (FASN) downregulates proinflammatory responses. We further show that metformin could suppress such elevation of FASN as well as proinflammatory activation in macrophages. In vivo, metformin treatment ameliorates dextran sulfate sodium (DSS)-induced colitis through impairing proinflammatory activation of colonic lamina propria mononuclear cells (LPMCs). The reduction of FASN by metformin hinders Akt palmitoylation, which further disturbs Akt membrane attachment and its phosphorylation. Metformin-mediated suppression of FASN/Akt pathway and its downstream MAPK signaling contributes to its anti-inflammatory role in macrophages. From the perspective of immunometabolism, our work points towards metformin utilization as an effective and potential intervention against macrophages-involved inflammatory diseases.

Macrocyclization of 3-triflyloxybenzynes with tetrahydrofuran via an anionic thia-Fries rearrangement.

A novel and uncommon macrocyclization reaction between 3-triflyloxybenzynes and tetrahydrofuran has been developed for the first time, providing a direct method for the synthesis of a range of functionalized 19-membered polyether macrocycles in moderate to good yields. The process was proposed to proceed through an anionic thia-Fris rearrangement under transition metal-free conditions, leading to the formation of four new C-O bonds and one new C-S bond in a single step.

Direct bromocarboxylation of arynes using allyl bromides and carbon dioxide.

An unprecedented three-component coupling involving arynes, allyl bromides, and CO2 is described, providing efficient and facile access to structurally diverse ortho-brominated aryl esters. Unlike the conventional role played in organic synthesis as electrophiles, organic bromides served as nucleophiles in this reaction, affording a new approach to multicomponent reactions (MCRs) involving aryne intermediates. Additionally, Hammett analysis suggests that two reaction mechanisms exist, depending on the electronic nature of the cinnamyl bromides used.

Direct Access to Trifluoromethyl-Substituted Carbamates from Carbon Dioxide via Copper-Catalyzed Cascade Cyclization of Enynes.

A copper-catalyzed cascade cyclization of enynes with Togni's reagent, carbon dioxide, and amines has been successfully developed. The reaction provides a direct and efficient route to a range of trifluoromethyl-substituted carbamates, which are difficult to access using existing methods. Mild reaction conditions, good functional tolerance, and wide substrate scope are the feactures of the protocol.

Copper-Catalyzed C-H Carbamoyloxylation of Aryl Carboxamides with CO2 and Amines at Ambient Conditions.

A copper-catalyzed, 8-aminoquinoline-assisted, one-pot three-component coupling of aryl carboxamides, CO2, and amines has been developed. This protocol proceeds smoothly in the presence of inexpensive CuI and MnO2 at room temperature under atmospheric CO2 pressure, leading to simultaneous construction of C-O and C-N bonds. The reaction displays a broad substrate scope, high functional group tolerance, and excellent monoselectivity, providing an operationally simple method for the synthesis of various O-aryl carbamates.

Iridium-Catalyzed Three-component Coupling Reaction of Carbon Dioxide, Amines, and Sulfoxonium Ylides.

The first iridium-catalyzed three-component coupling reaction of carbon dioxide, amines, and sulfoxonium ylides has been developed, providing an efficient and straightforward method for the construction of a range of structurally diverse O-ß-oxoalkyl carbamates in moderate to excellent yields. This novel protocol features the use of readily available substrates, wide substrate scope, and good functional group tolerance. Moreover, the phosgene-free strategy was successfully applied to the synthesis of a potential antitumor agent.

A Three-Phase Four-Component Coupling Reaction: Selective Synthesis of o-Chloro Benzoates by KCl, Arynes, CO2, and Chloroalkanes.

A transition-metal-free three-phase four-component coupling reaction (3P-4CR) involving KCl, arynes, chloroalkanes and CO2 has been reported for the first time, enabling the incorporation of both chloro and CO2 into an aryne simultaneously. The reactions for the synthesis of different types of o-chloro benzoates can be selectively modulated by the chloroalkane utilized. The corresponding products can be alternatively transformed for postsynthetic functionalizations conveniently.

A four-component coupling reaction of carbon dioxide, amines, cyclic ethers and 3-triflyloxybenzynes for the synthesis of functionalized carbamates.

A novel four-component coupling reaction of carbon dioxide, amines, cyclic ethers and 3-triflyloxybenzynes has been developed for the first time, providing an efficient method for the synthesis of a series of functionalized carbamate derivatives in moderate to high yields. The process proceeds under mild, transition metal-free and fluoride-free conditions, leading to the formation of two new C-O bonds, one new C-N bond and one C-H bond in a single step.

Palladium-Catalyzed Four-Component Cascade Reaction for the Synthesis of Highly Functionalized Acyclic O,O-Acetals.

A palladium-catalyzed four-component cascade reaction of carbon dioxide, amines, allenyl ethers, and aryl iodides has been developed for the first time. The novel reaction allows simultaneous construction of three different new bonds (C-N, C-O, and C-C) in a single step, affording an efficient method for the synthesis of a variety of highly functionalized acyclic O,O-acetals. Excellent chemo- and regioselectivity, wide substrate scope, and good functional group tolerance are features of the method.

Palladium-Catalyzed Synthesis of 1H-Indenes and Phthalimides via Isocyanide Insertion.

A new and versatile multicomponent domino strategy has been developed for the synthesis of a series of 1H-indene and phthalimide derivatives from simple and readily available starting materials. This process operating under mild conditions shows a broad substrate scope with moderate to excellent yields.