Discovery of Urea Derivatives of Celastrol as Selective Peroxiredoxin 1 Inhibitors against Colorectal Cancer Cells.

Peroxiredoxin (PRDX1) is a tumor-overexpressed antioxidant enzyme for eliminating excessive reactive oxygen species (ROS) to protect tumor cells from oxidative damage. Herein, a series of celastrol urea derivatives were developed based on its cocrystal structure with PRDX1, with the aim of pursuing a PRDX1-specific inhibitor. Among them, derivative 15 displayed potent anti-PRDX1 activity (IC50 = 0.35 µM) and antiproliferative potency against colon cancer cells. It covalently bound to Cys-173 of PRDX1 (KD = 0.37 µM), which was secured by the cocrystal structure of PRDX1 with an analogue of 15 while exhibiting weak inhibitory effects on PRDX2-PRDX6 (IC50 > 50 µM), indicating excellent PRDX1 selectivity. Treatment with 15 dose-dependently decreased the mitochondria membrane potential of SW620 cells, probably due to ROS induced by PRDX1 inhibition, leading to cell apoptosis. In colorectal cancer cell xenograft model, it displayed potent antitumor efficacy with superior safety to celastrol. Collectively, 15 represents a promising PRDX1 selective inhibitor for the development of anticolorectal cancer agents.

Design, Synthesis, and Pharmacological Evaluation of Spiro[carbazole-3,3'-pyrrolidine] Derivatives as cGAS Inhibitors for Treatment of Acute Lung Injury.

Overactivation of cyclic GMP-AMP synthase (cGAS) is implicated in the occurrence of many inflammatory and autoimmune diseases, and inhibition of cGAS with a specific inhibitor has been proposed as a potential therapeutic strategy. However, only a few low-potency cGAS inhibitors have been reported, and few are suitable for clinical investigation. As a continuation of our structural optimization on the reported cGAS inhibitor 6 (G140), we developed a series of spiro[carbazole-3,3'-pyrrolidine] derivatives bearing a unique 2-azaspiro[4.5]decane structural motif, among which compound 30d-S was identified with high cellular effects against cGAS. This compound showed improved plasma exposure, lower clearance, and an oral bioavailability of 35% in rats. Moreover, in the LPS-induced acute lung injury (ALI) mice model, oral administration of compound 30d-S at 30 mg/kg markedly reduced lung inflammation and alleviated histopathological changes. These results confirm that 30d-S is a new efficacious cGAS inhibitor and is worthy of further investigation.

Discovery of a Highly Potent Oxysterol Receptor GPR183 Antagonist Bearing the Benzo[d]thiazole Structural Motif for the Treatment of Inflammatory Bowel Disease (IBD).

Accumulating evidence has demonstrated a critical pathological role of oxysterol receptor GPR183 in various inflammatory and autoimmune diseases, including inflammatory bowel disease (IBD). However, the currently reported GPR183 antagonists are very limited and not qualified for in vivo studies due to their inferior druglike properties. Herein, we conducted a structural elaboration focusing on improving its PK and safety profile based on a reference antagonist NIBR189. Of note, compound 33, bearing an aminobenzothiazole motif, exhibited reduced hERG inhibition, improved PK properties, and robust antagonistic activity (IC50 = 0.82 nM) with high selectivity against GPR183. Moreover, compound 33 displayed strong in vitro antimigration and anti-inflammatory activity in monocytes. Oral administration of compound 33 effectively improved the pathological symptoms of DSS-induced experimental colitis. All of these findings demonstrate that compound 33 is a novel and promising GPR183 antagonist suitable for further investigation to treat IBD.

Design, Synthesis, and Pharmacological Evaluation of Isoindoline Analogues as New HPK1 Inhibitors.

Hematopoietic progenitor kinase 1 (HPK1) is an important negative regulator in T-cell receptor signaling and as a promising key target for immunotherapy. Herein, based on the reported HPK1 inhibitor 2 featuring an isofuranone component, a structural optimization approach was conducted leading to several series of derivatives characterized by containing an isoindoline structural motif. Compound 49 was identified as a new potent HPK1 inhibitor with an IC50 value of 0.9 nM, more potent than compound 2 (5.5 nM). It also has an improved IV profile in rats and enhanced aqueous solubility. It effectively inhibited pSLP76 and reinvigorated T-cell receptor (TCR) signaling, promoting T-cell function and cytokine production both in naïve and antigen-specific T cells. Furthermore, compound 49 reversed the inhibition on T-cell activity mediated by classic immunosuppressive factors in the tumor microenvironment (TME). In the murine CT-26 tumor model, this compound reinvigorated the T cell and synergistically enhanced the antitumor efficacy of anti-PD1 at a well-tolerant dosage.

Design, Synthesis, and Pharmacological Evaluation of Multisubstituted Pyrido[4,3-d]pyrimidine Analogues Bearing Deuterated Methylene Linkers as Potent KRASG12D Inhibitors.

The breakthrough in drug development of KRASG12C inhibitors provides inspiration for targeting alternative KRAS mutations, especially the most prevalent KRASG12D variant. Based on the structural analysis of MRTX1133 in complex with KRASG12D, a comprehensive structure-activity study was conducted, which led to the discovery of several compounds (22, 28, and 31) that showed higher potency in suppressing the clonogenic growth of KRASG12D-dependent cancer cells. These new compounds markedly and selectively inhibited the binding of RBD peptide to GTP-bound KRASG12D with IC50 values between 0.48 and 1.21 nM. These new inhibitors were found to have dose-dependent anti-tumor efficacy in the AsPC-1 xenograft mouse models with a tumor growth inhibition of approximately 70% at a dose of 20 mg/kg twice daily (i.p.). Despite the non-optimal pharmacokinetic properties similar to those of MRTX1133, the high in vitro and in vivo potency of these new inhibitors call for further profiling.

Discovery of Triazolyl Derivatives of Cucurbitacin B Targeting IGF2BP1 against Non-Small Cell Lung Cancer.

Cucurbitacin B (CuB) is a potent but toxic anticancer natural product. Herein, we designed and synthesized 2-OH- and 16-OH-modified CuB derivatives to improve their antitumor efficacy and reduce toxicity. Among them, derivative A11 had the most potent antiproliferative activity against A549 lung cancer cells (IC50 = 0.009 µM) and was approximately 10-fold more potent than CuB, while the cytotoxicity of A11 toward normal L02 cells was about 10-fold less potent, indicating a much wider therapeutic window than CuB. Derivative A11 directly binds to the insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) protein with a KD value of 2.88 nM, which is about 23-fold more potent than CuB, leading to the decreased expression of downstream apoptosis- and cell cycle-related proteins. More importantly, A11 exhibited much more potent anticancer efficacy in an A549 xenograft mouse model with a TGI rate of 80% and a superior in vivo safety profile than that of CuB.

Photochemically controlled activation of STING by CAIX-targeting photocaged agonists to suppress tumor cell growth.

Controllable activation of the innate immune adapter protein - stimulator of interferon genes (STING) pathway is a critical challenge for the clinical development of STING agonists due to the potential "on-target off-tumor" toxicity caused by systematic activation of STING. Herein, we designed and synthesized a photo-caged STING agonist 2 with a tumor cell-targeting carbonic anhydrase inhibitor warhead, which could be readily uncaged by blue light to release the active STING agonist leading to remarkable activation of STING signaling. Furthermore, compound 2 was found to preferentially target tumor cells, stimulate the STING signaling in zebrafish embryo upon photo-uncaging and to induce proliferation of macrophages and upregulation of the mRNA expression of STING as well as its downstream NF-kB and cytokines, thus leading to significant suppression of tumor cell growth in a photo-dependent manner with reduced systemic toxicity. This photo-caged agonist not only provides a powerful tool to precisely trigger STING signalling, but also represents a novel controllable STING activation strategy for safer cancer immunotherapy.

CYD0281, a Bcl-2 BH4 domain antagonist, inhibits tumor angiogenesis and breast cancer tumor growth.

BACKGROUND: B-cell lymphoma 2 (Bcl-2) family proteins are key regulators of apoptosis, which possess four conserved Bcl-2 homologies (BH) domains. Among the BH domains, the BH3 domain is considered as a potent 'death domain' while the BH4 domain is required for anti-apoptotic activity. Bcl-2 can be converted to a pro-apoptotic molecule through the removal or mutation of the BH4 domain. Bcl-2 is considered as an inducer of angiogenesis, which can promote tumor vascular network formation and further afford nutrients and oxygen to promote tumor progression. However, whether disrupting the function of the BH4 domain to convert Bcl-2 into a pro-apoptotic molecule could make Bcl-2 possess the potential for anti-angiogenic therapy remains to be defined. METHODS: CYD0281 was designed and synthesized according to the lead structure of BDA-366, and its function on inducing a conformational change of Bcl-2 was further evaluated via immunoprecipitation (IP) and immunofluorescence (IF) assays. Moreover, the function of CYD0281 on apoptosis of endothelial cells was analyzed via cell viability, flow cytometry, and western blotting assays. Additionally, the role of CYD0281 on angiogenesis in vitro was determined via endothelial cell migration and tube formation assays and rat aortic ring assay. Chick embryo chorioallantoic membrane (CAM) and yolk sac membrane (YSM) models, breast cancer cell xenograft tumor on CAM and in mouse models as well as the Matrigel plug angiogenesis assay were used to explore the effects of CYD0281 on angiogenesis in vivo. RESULTS: We identified a novel potent small-molecule Bcl-2-BH4 domain antagonist, CYD0281, which exhibited significant anti-angiogenic effects both in vitro and in vivo, and further inhibited breast cancer tumor growth. CYD0281 was found to induce conformational changes in Bcl-2 through the exposure of the BH3 domain and convert Bcl-2 from an anti-apoptotic molecule into a cell death inducer, thereby resulting in the apoptosis of vascular endothelial cells. CONCLUSIONS: This study has revealed CYD0281 as a novel Bcl-2-BH4 antagonist that induces conformational changes of Bcl-2 to convert to a pro-apoptotic molecule. Our findings indicate that CYD0281 plays a crucial role in anti-angiogenesis and may be further developed as a potential anti-tumor drug candidate for breast cancer. This work also provides a potential anti-angiogenic strategy for breast cancer treatment.

Discovery of 2H-Indazole-3-carboxamide Derivatives as Novel Potent Prostanoid EP4 Receptor Antagonists for Colorectal Cancer Immunotherapy.

Nowadays, small-molecule drugs have become an indispensable part of tumor immunotherapy. Accumulating evidence has indicated that specifically blocking PGE2/EP4 signaling to induce robust antitumor immune response represents an attractive immunotherapy strategy. Herein, a 2H-indazole-3-carboxamide containing compound 1 was identified as a EP4 antagonist hit by screening our in-house small-molecule library. Systematic structure-activity relationship exploration leads to the discovery of compound 14, which displayed single-nanomolar EP4 antagonistic activity in a panel of cell functional assays, high subtype selectivity, and favorable drug-like profiles. Moreover, compound 14 profoundly inhibited the up-regulation of multiple immunosuppression-related genes in macrophages. Oral administration of compound 14, either as monotherapy or in combination with an anti-PD-1 antibody, significantly impaired tumor growth via enhancing cytotoxic CD8+ T cell-mediated antitumor immunity in a syngeneic colon cancer model. Thus, these results demonstrate the potential of compound 14 as a candidate for developing novel EP4 antagonists for tumor immunotherapy.

Celastrol suppresses colorectal cancer via covalent targeting peroxiredoxin 1.

As a terpenoids natural product isolated from the plant Thunder God Vine, Celastrol is widely studied for its pharmacological activities, including anti-tumor activities. The clinical application of Celastrol is strictly limited due to its severe side effects, whereas previously revealed targets and mechanism of Celastrol seldom reduce its in vivo toxicity via structural optimization. Target identification has a far-reaching influence on the development of innovative drugs, and omics data has been widely used for unbiased target prediction. However, it is difficult to enrich target of specific phenotype from thousands of genes or proteins, especially for natural products with broad promising activities. Here, we developed a text-mining-based web-server tool to enrich targets from omics data of inquired compounds. Then peroxiredoxin 1 (PRDX1) was identified as the ROS-manipulating target protein of Celastrol in colorectal cancer. Our solved high-resolution crystal structure revealed the unique covalent binding mode of Celastrol with PRDX1. New derivative compound 19-048 with improved potency against PRDX1 and selectivity towards PRDX2~PRDX6 were synthesized based on crystal structure analysis. Both Celastrol and 19-048 effectively suppressed the proliferation of colorectal cancer cells. The anti-tumor efficacy of Celastrol and 19-048 was significantly diminished on xenograft nude mice bearing PRDX1 knock-down colorectal cancer cells. Several downstream genes of p53 signaling pathway were dramatically up-regulated with Celastrol or 19-048 treatment. Our findings reveal that the side effects of Celastrol could be reduced via structural modification, and PRDX1 inhibition is promising for the treatment of colorectal cancer.

Acid-Ionizable Iron Nanoadjuvant Augments STING Activation for Personalized Vaccination Immunotherapy of Cancer.

The critical challenge for cancer vaccine-induced T-cell immunity is the sustained activation of antigen cross-presentation in antigen-presenting cells (APCs) with innate immune stimulation. In this study, it is first discovered that the clinically used magnetic contrast agents, iron oxide nanoparticles (IONPs), markedly augment the type-I interferon (IFN-I) production profile of the stimulator of interferon genes (STING) agonist MSA-2 and achieve a 16-fold dosage-sparing effect in the human STING haplotype. Acid-ionizable copolymers are coassembled with IONPs and MSA-2 into iron nanoadjuvants to concentrate STING activation in the draining lymph nodes. The top candidate iron nanoadjuvant (PEIM) efficiently delivers the model antigen ovalbumin (OVA) to CD169+ APCs and facilitates antigen cross-presentation to elicit a 55-fold greater frequency of antigen-specific CD8+ cytotoxic T-lymphocyte response than soluble antigen. PEIM@OVA nanovaccine immunization induces potent and durable antitumor immunity to prevent tumor lung metastasis and eliminate established tumors. Moreover, PEIM nanoadjuvant is applicable to deliver autologous tumor antigen and synergizes with immune checkpoint blockade therapy for prevention of postoperative tumor recurrence and distant metastasis in B16-OVA melanoma and MC38 colorectal tumor models. The acid-ionizable iron nanoadjuvant offers a generalizable and readily translatable strategy to augment STING cascade activation and antigen cross-presentation for personalized cancer vaccination immunotherapy.

Tanshinone functions as a coenzyme that confers gain of function of NQO1 to suppress ferroptosis.

Ferroptosis is triggered by the breakdown of cellular iron-dependent redox homeostasis and the abnormal accumulation of lipid ROS. Cells have evolved defense mechanisms to prevent lipid ROS accumulation and ferroptosis. Using a library of more than 4,000 bioactive compounds, we show that tanshinone from Salvia miltiorrhiza (Danshen) has very potent inhibitory activity against ferroptosis. Mechanistically, we found that tanshinone functions as a coenzyme for NAD(P)H:quinone oxidoreductase 1 (NQO1), which detoxifies lipid peroxyl radicals and inhibits ferroptosis both in vitro and in vivo. Although NQO1 is recognized as an oxidative stress response gene, it does not appear to have a direct role in ferroptosis inhibition in the absence of tanshinone. Here, we demonstrate a gain of function of NQO1 induced by tanshinone, which is a novel mechanism for ferroptosis inhibition. Using mouse models of acute liver injury and ischemia/reperfusion heart injury, we observed that tanshinone displays protective effects in both the liver and the heart in a manner dependent on NQO1. Our results link the clinical use of tanshinone to its activity in ferroptosis inhibition.

Synthesis and anti-tumor activity of nitrogen-containing derivatives of the natural product diphyllin.

The natural product diphyllin has demonstrated great potential in the treatment of various human cancers, especially pancreatic cancer. However, its relative weak potency, low aqueous solubility, and poor metabolic stability limits its development ability. In this study, we designed and synthesized two series of novel nitrogen-containing diphyllin derivatives with the aim to improve both antitumor efficacy and drug-like properties. Among them, the amino derivative 15 showed an IC50 value of 3 nM against pancreatic cancer CFPAC-1 cells and is about 69-fold more potent than diphyllin. In addition, compound 15 possesses improved aqueous solubility and metabolic stability in liver microsomes. This compound not only significantly induced cell cycle arrest at G0/G1 phase with down-regulation of CDK4 and cyclinD1 in a dose-dependent manner, but also blocked the later stage of autophagy in CFPAC-1 cells. In pancreatic cancer xenograft model, treatment of 15 with 10 mg/kg exhibited much more potent efficacy in suppressing the growth of transplanted PANC02 tumors than diphyllin without obvious safety concern.

Structure-Activity relationship study of benzothiophene oxobutanoic acid analogues leading to novel stimulator of interferon gene (STING) agonists.

Pharmacological activation of stimulator of interferon genes (STING) by agonists has emerged as a new modality of cancer immunotherapy. However, current available STING agonists remain in early developmental stage or failed in clinic trials due to limited efficacy in humans. In this report, we performed a structure-activity relationship study based on the benzothiophene oxobutanoic acid scaffold of MSA-2, a well-documented STING agonist by Merck, leading to a series of N-substituted acyloxyamino derivatives with potent STING activating effect. Among them, compounds 57 and 60 displayed the most potent activity specifically targeting both h- and m-STING. Particularly, 57 displayed more potent and rapid activation of the STING signaling pathway than ADU-S100 in THP1-Dual cells. In vivo anti-tumor efficacy of 57 by intratumoral or oral administration was also demonstrated in several mouse tumor models. Intriguingly, treatment with 57 eradicated all the CT26 tumor without further recurrence in all treated mice, which could also reject the same tumor re-inoculation, indicating an induction of immune memory by 57. Taken together, acyloxyamino derivative 57 represents a new chemotype of STING agonist with well-demonstrated in vivo anti-tumor activity, which is deserved for further investigation.

Design, synthesis and pharmacological evaluation of new PARP1 inhibitors by merging pharmacophores of olaparib and the natural product alantolactone.

Based on the reported synthetic lethality of the combination of PARP inhibitor olaparib with the natural product alantolactone, we designed several series of new PARP1 inhibitors by structurally merging both compounds into a single hybrid compound. Among them, compounds 20e and 25a displayed not only high biochemical activity (IC50 = 2.99 nM and 5.91 nM vs 11.36 nM), but also higher inhibitory effects against proliferation of BRCA1-deficient UWB1.289 cells than olaparib (IC50 = 0.27 µM and 0.41 µM vs 0.66 µM). Much weak activity was observed in BRCA1 wild-type human fetal lung IMR-90 and WI-38 cells (IC50s > 10 µM). Treatment with compounds 20e and 25a was found to induce increased levels of γH2AX in a concentration-dependent manner in both MDA-MB-436 and Capan-1 cells to a degree comparable with that of olaparib. Further mechanism study indicated that these compounds activated the cell cycle checkpoints, and subsequently induced G2/M arrest and apoptosis. The results validated that merging PARP inhibitors with other DNA-damage related compounds would produce more potent PARP inhibitors for anticancer studies. However, the poor aqueous solubility and low cell penetration of the current hybrid compounds call for further structural optimization.

Piezo-Type Mechanosensitive Ion Channel Component 1 (Piezo1): A Promising Therapeutic Target and Its Modulators.

Piezo1 is a member of the mechanosensitive piezo ion channel family, which transduces various mechanical stimulations into electrochemical signals. Piezo1 is closely implicated in different physiological processes ranging from erythrocyte volume homeostasis to lymphatic vessel formation and bone homeostasis. Aberrant Piezo1 functions caused by gain-of-function or loss-of-function mutations are associated with various pathological conditions. Due to the significant contribution on the recognition of Piezo ion channels for sensing mechanical stress, Ardem Patapoutian received the 2021 Nobel Prize in Physiology or Medicine (jointly). Strategies of targeting and modulating Piezo1 have shown potential to produce significant therapeutic effects, thus validating Piezo1 as a promising drug target for diseases. In this Perspective, we review the cryo-EM structure, mechanogating mechanism, and physiological profiles of Piezo1, together with the latest advances in the development of its modulators. Limitations and challenges as well as future development of Piezo1 modulators are discussed as well.

Synthesis and pharmacological validation of fluorescent diarylsulfonylurea analogues as NLRP3 inhibitors and imaging probes.

The NOD-like receptor family pyrin domain-containing protein 3 (NLRP3) is a key cytosolic pattern recognition receptor that senses diverse pathogen- and host-originated threat signals. Aberrant activation of NLRP3 inflammasomes is closely associated with the pathogenesis of various complex inflammatory diseases. Nevertheless, the detailed regulation mechanism of NLRP3 inflammasome and its pathogenic roles in the inflammation progression remain to be fully elucidated. Fluorescent imaging with small molecule probe can provide valuable visualization information on the expression, occupancy and bio-distribution of target protein. Herein, we reported a series of diarylsulfonylurea NLRP3 fluorescent inhibitors bearing an amino benzodiazole fluorophore. Compared to the previously reported NLRP3 fluorescent probes, these inhibitors are more structurally concise and membrane permeable due to no additionally appended fluorophore via a linker. Among this series, compound 13a exhibited the most potent cellular NLRP3 inhibitory effect with an IC50 value of 49 nM, and significantly suppressed LPS/Nigericin-induced secretion of active caspase-1 and mature IL-1ß in a dose-dependent manner to block the activation of NLRP3 inflammasome. Meanwhile, this new probe exhibited promising fluorescent properties for specifically detecting and imaging the LPS-induced or constitutively expressed NLRP3 proteins in RAW264.7 cells. Collectively, probe 13a is a potent NLRP3 fluorescent inhibitor with cellular NLRP3 imaging ability, which is useful for NLRP3 inhibitor screening and related mechanism study.

Analysis of cancer-promoting genes related to chemotherapy resistance in esophageal squamous cell carcinoma.

Background: According to histopathology, esophageal cancer can be divided into squamous cell carcinoma (SCC) and esophageal adenocarcinoma (adeno arcinoma). In China, 90% of esophageal cancer patients are squamous cell carcinoma. Cisplatin and fluaziridine are the main chemotherapy before and after surgery. Long-term drug treatment is often accompanied by the emergence of drug resistance of tumor cells. There are many mechanisms for the emergence of drug resistance of tumor cells, including the increase of drug efflux, the decrease of drug intake, the inhibition of cell apoptosis, and so on. This study aimed to investigate the key cancer-promoting genes related to chemotherapy resistance in esophageal squamous cell carcinoma (ESCC). Methods: Two datasets from the Gene Expression Omnibus (GEO) database (GSE86099 and GSE50224) were retrieved. We performed microRNA (miRNA) and messenger RNA (mRNA) expression analysis to identify differentially expressed genes (DEGs). The intersection of the downregulated miRNA targets and the upregulated mRNAs were used for Gene Ontology (GO) enrichment analysis, and survival risk was assessed using data from The Cancer Genome Atlas (TCGA). Results: There were 35 common genes, of which, based on GO enrichment, most were related to the cardiac muscle cell action. Four genes showed significant association with the estimated half-maximal inhibitory concentration (IC50) of paclitaxel: bone morphogenetic protein 1 (BMP1), dumbbell former 4 protein (DBF4), angiogenin (ANG), and MAP7 domain containing 2 (MAP7D2). Four risk factors (MP1, HIP1, ANG, and MAP7D2) were selected to generate a signature using least absolute shrinkage and selection operator (LASSO) regression. Protein-protein interaction (PPI) analysis showed guanine nucleotide-binding protein subunit beta 4 (GNB4), calcium voltage-gated channel auxiliary subunit beta 2 (CACNB2), and sodium voltage-gated channel alpha subunit 1 (SCN1A) were located at key positions of the network. Among potential risk genes, only the high expression of dedicator of cytokinesis 8 (DOCK8) was associated with poorer survival. Conclusions: The 35 oncogenes may be involved in mechanisms of chemotherapy resistance in ESCC, as well as the corresponding enrichment and regulatory network. The signature containing 4 key risk genes merits further investigation and may provide a deeper understanding of the molecular mechanisms in ESCC treatment failure.

Activatable NIR-II Fluorescent Nanoprobe for Rapid Detection and Imaging of Methylglyoxal Facilitated by the Local Nonpolar Microenvironment.

Closely related to multiple chronic inflammation, especially type-2 diabetes (T2D), methylglyoxal (MGO) may be a potential key to visualize disease progression and treatment effects. On the other hand, lack of convenient and fast analytical methods cannot afford accurate MGO quantitative evaluation. In this work, an activatable second near-infrared region (NIR-II) fluorescent probe TDTCD was synthesized and its reaction mechanism with MGO was discussed. The desired NIR-II product preferred response solvents with small polarity. A novel activatable nanoprobe, MG-SLNP, for MGO was then constructed based on rational packaging to provide a local nonpolar microenvironment. The hydrophobic core of nanoparticles not only successfully improved the stability and water solubility but also greatly promoted the response rate while reacting with MGO. The comparison between NIR-II fluorescence and the traditional high-performance liquid chromatography method for T2D blood samples was discussed. A high-resolution viewing window, quick response, and good biocompatibility led to a satisfactory signal-to-noise ratio of MG-SLNP for real-time MGO bio-detection and imaging in vivo.

Synthesis and Pharmacological Evaluation of Tetrahydro-γ-carboline Derivatives as Potent Anti-inflammatory Agents Targeting Cyclic GMP-AMP Synthase.

The activation of cyclic GMP-AMP synthase (cGAS) by double-stranded DNA is implicated in the pathogenesis of many hyperinflammatory and autoimmune diseases, and the cGAS-targeting small molecule has emerged as a novel therapeutic strategy for treating these diseases. However, the currently reported cGAS inhibitors are far beyond maturity, barely demonstrating in vivo efficacy. Inspired by the structural novelty of compound 5 (G140), we conducted a structural optimization on both its side chain and the central tricyclic core, leading to several subseries of compounds, including those unexpectedly cyclized complex ones. Compound 25 bearing an N-glycylglycinoyl side chain was identified as the most potent one with cellular IC50 values of 1.38 and 11.4 µM for h- and m-cGAS, respectively. Mechanistic studies confirmed its direct targeting of cGAS. Further, compound 25 showed superior in vivo anti-inflammatory effects in the lipopolysaccharide-induced mouse model. The encouraging result of compound 25 provides solid evidence for further pursuit of cGAS-targeting inhibitors as a new anti-inflammatory treatment.