Effect of TRPV4 Antagonist GSK2798745 on Chlorine Gas-Induced Acute Lung Injury in a Swine Model.

As a regulator of alveolo-capillary barrier integrity, Transient Receptor Potential Vanilloid 4 (TRPV4) antagonism represents a promising strategy for reducing pulmonary edema secondary to chemical inhalation. In an experimental model of acute lung injury induced by exposure of anesthetized swine to chlorine gas by mechanical ventilation, the dose-dependent effects of TRPV4 inhibitor GSK2798745 were evaluated. Pulmonary function and oxygenation were measured hourly; airway responsiveness, wet-to-dry lung weight ratios, airway inflammation, and histopathology were assessed 24 h post-exposure. Exposure to 240 parts per million (ppm) chlorine gas for ≥50 min resulted in acute lung injury characterized by sustained changes in the ratio of partial pressure of oxygen in arterial blood to the fraction of inspiratory oxygen concentration (PaO2/FiO2), oxygenation index, peak inspiratory pressure, dynamic lung compliance, and respiratory system resistance over 24 h. Chlorine exposure also heightened airway response to methacholine and increased wet-to-dry lung weight ratios at 24 h. Following 55-min chlorine gas exposure, GSK2798745 marginally improved PaO2/FiO2, but did not impact lung function, airway responsiveness, wet-to-dry lung weight ratios, airway inflammation, or histopathology. In summary, in this swine model of chlorine gas-induced acute lung injury, GSK2798745 did not demonstrate a clinically relevant improvement of key disease endpoints.

Liproxstatin-1 attenuates acute hypertriglyceridemic pancreatitis through inhibiting ferroptosis in rats.

Ferroptosis is closely associated with inflammatory diseases, including acute pancreatitis (AP); however, the involvement of ferroptosis in hypertriglyceridemic pancreatitis (HTGP) remains unclear. In the present study, we aimed to explore the relationship between lipid metabolism and ferroptosis in HTGP and the alleviating effect of liproxstatin-1 (Lip-1) in vivo. This study represents the first exploration of lipid metabolism and endoplasmic reticulum stress (ERS) in HTGP, targeting ferroptosis as a key factor in HTGP. Hypertriglyceridemia (HTG) was induced under high-fat diet conditions. Cerulein was then injected to establish AP and HTGP models. Lip-1, a specific ferroptosis inhibitor, was administered before the induction of AP and HTGP in rats, respectively. Serum triglyceride, amylase, inflammatory factors, pathological and ultrastructural structures, lipid peroxidation, and iron overload indicators related to ferroptosis were tested. Moreover, the interaction between ferroptosis and ERS was assessed. We found HTG can exacerbate the development of AP, with an increased inflammatory response and intensified ferroptosis process. Lip-1 treatment can attenuate pancreatic injury by inhibiting ferroptosis through lipid metabolism and further resisting activations of ERS-related proteins. Totally, our results proved lipid metabolism can promote ferroptosis in HTGP by regulating ACSL4/LPCAT3 protein levels. Additionally, ERS may participate in ferroptosis via the Bip/p-EIF2α/CHOP pathway, followed by the alleviating effect of Lip-1 in the rat model.

Genome-guided discovery of two undescribed 6,6-spiroketal polyketides and stereochemical correction of bafilomycins P and Q from the marine-derived Streptomyces sp. SCSIO 66814.

Bafilomycins are macrocyclic polyketides with intriguing structures and therapeutic value. Genomic analysis of Streptomyces sp. SCSIO 66814 revealed a type I polyketide synthase biosynthetic gene cluster (BGC), namely blm, which encoded bafilomycins and featured rich post-modification genes. The One strain many compounds (OSMAC) strategy led to the discovery of six compounds related to the blm BGC from the strain, including two previously undescribed 6,6-spiroketal polyketides, streptospirodienoic acids D (1) and E (2), and four known bafilomycins, bafilomycins P (3), Q (4), D (5), and G (6). The structures of 1 and 2 were determined by extensive spectroscopic analysis, quantum calculation, and biosynthetic analysis. Additionally, the absolute configurations of the 6/5/5 tricyclic ring moiety containing six consecutive chiral carbons in the putative structures of 3 and 4 were corrected through NOE analysis, DP4+ calculation, and single-crystal X-ray diffraction data. Bioinformatic analysis uncovered a plausible biosynthetic pathway for compounds 1-6, indicating that both streptospirodienoic acids and bafilomycins were derived from the same blm BGC. Additionally, sequence analysis revealed that the KR domains of module 2 from blm BGC was B1-type, further supporting the configurations of 1-4. Notably, compounds 3 and 4 displayed significant cytotoxic activities against A-549 human non-small cell lung cancer cells and HCT-116 human colon cancer cells.

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.

Synthesis and antiproliferative activity of a tetrahydrofuran analog of FR901464.

FR901464 is a natural product that exhibits antiproliferative activity at single-digit nanomolar concentrations in cancer cells. Its tetrahydropyran-spiroepoxide covalently binds the spliceosome. Through our medicinal chemistry campaign, we serendipitously discovered that a bromoetherification formed a tetrahydrofuran. The tetrahydrofuran analog was three orders of magnitude less potent than the corresponding tetrahydropyran analogs. This study shows the significance of the tetrahydropyran ring that presents the epoxide toward the spliceosome.

Evaluating the potency of zoliflodacin against Helicobacter pylori: In vitro activity and conserved GyrB target.

BACKGROUND: The current standard treatment for Helicobacter pylori infection, which involves a combination of two broad-spectrum antibiotics, faces significant challenges due to its detrimental impact on the gut microbiota and the emergence of drug-resistant strains. This underscores the urgent requirement for the development of novel anti-H. pylori drugs. Zoliflodacin, a novel bacterial gyrase inhibitor, is currently undergoing global phase III clinical trials for treating uncomplicated Neisseria gonorrhoeae. However, there is no available data regarding its activity against H. pylori. MATERIALS AND METHODS: We evaluated the in vitro activity of zoliflodacin against H. pylori clinical isolates (n = 123) with diverse multidrug resistance. We performed DNA gyrase supercoiling and microscale thermophoresis assays to identify the target of zoliflodacin in H. pylori. We analyzed 2262 H. pylori whole genome sequences to identify Asp424Asn and Lys445Asn mutations in DNA gyrase subunit B (GyrB) that are associated with zoliflodacin resistance. RESULTS: Zoliflodacin exhibits potent activity against all tested isolates, with minimal inhibitory concentration (MIC) values ranging from 0.008 to 1 µg/mL (MIC50: 0.125 µg/mL; MIC90: 0.25 µg/mL). Importantly, there was no evidence of cross-resistance to any of the four first-line antibiotics commonly used against H. pylori. We identified GyrB as the primary target of zoliflodacin, with Asp424Asn or Lys445Asn substitutions conferring resistance. Screening of 2262 available H. pylori genomes for the two mutations revealed only one clinical isolate carrying Asp424Asn substitution. CONCLUSION: These findings support the potential of zoliflodacin as a promising candidate for H. pylori treatment, warranting further development and evaluation.

Preventive Treatment of Migraine.

OBJECTIVE: This article describes strategies for the preventive treatment of migraine including the emerging role of calcitonin gene-related peptide (CGRP)-targeted therapies and introduces novel paradigms for the preventive treatment of migraine. LATEST DEVELOPMENTS: Multiple migraine medications targeting CGRP have been introduced since 2018, including injectable monoclonal antibodies (ie, eptinezumab, erenumab, fremanezumab, and galcanezumab) and oral small-molecule CGRP receptor antagonists (ie, ubrogepant, rimegepant, atogepant, and zavegepant). With the exceptions of ubrogepant and zavegepant, which are approved only as acute treatments, all of these agents have demonstrated efficacy in the preventive treatment of migraine; the monoclonal antibodies and atogepant have evidence of effectiveness in adults with either episodic or chronic migraine. The safety and tolerability profiles of CGRP-targeted therapies in migraine are favorable. ESSENTIAL POINTS: The goals of preventive migraine therapy include reducing the frequency, severity, duration, and disability associated with attacks, reducing the need for acute treatment and the risk of medication overuse, enhancing self-efficacy and health-related quality of life, and reducing headache-related distress and interictal burden. Six drugs targeting CGRP (four monoclonal antibodies and two gepants) are now available for the preventive treatment of episodic migraine in adults. The efficacy of CGRP-targeted medications in the acute and preventive treatment of migraine, together with good safety and tolerability, has led to the emergence of new approaches to preventive treatment.

Ferroptosis contributes to airway epithelial E-cadherin disruption in a mixed granulocytic asthma mouse model.

Aberrant expression of airway epithelial E-cadherin is a key feature of asthma, yet the underlying mechanisms are largely unknown. Ferroptosis is a novel form of regulated cell death involved in asthma pathogenesis. This study was aimed to evaluate the role of ferroptosis and to investigate whether ferroptosis mediates E-cadherin disruption in mixed granulocyte asthma (MGA). Two murine models of MGA were established using toluene diisocyanate (TDI) or ovalbumin with Complete Freund's Adjuvant (OVA/CFA). Specific antagonists of ferroptosis, including Liproxstatin-1 (Lip-1) and Ferrostatin-1 (Fer-1) were given to the mice. The allergen-exposed mice displayed markedly shrunk mitochondria in the airway epithelia, with decreased volume and denser staining accompanied by down-regulated GPX4 as well as up-regulated FTH1 and malondialdehyde, which are markers of ferroptosis. Decreased pulmonary expression of E-cadherin was also observed, with profound loss of membrane E-cadherin in the airway epithelia, as well as increased secretion of sE-cadherin. Treatment with Lip-1 not only showed potent protective effects against the allergen-induced airway hyperresponsiveness and inflammatory responses, but also rescued airway epithelial E-cadherin expression and inhibited the release of sE-cadherin. Taken together, our data demonstrated that ferroptosis mediates airway epithelial E-cadherin dysfunction in MGA.

Isolation of undescribed cladosporols and spirobisnaphthalenes from a plant pathogen Cladosporium cladosporioides F-10-2-A.

Two undescribed cladosporol derivatives, cladosporols J-K (1-2), and three previously unreported spirobisnaphthalenes, urnucratins D-F (3-5), as well as eleven known cladosporols (6-16), were characterized from Cladosporium cladosporioides (Cladosporiaceae), a common plant pathogen isolated from the skin of Chinese toad. Cladosporols J-K (1-2) with a single double bond have been rarely reported, while urnucratins D-F (3-5) featured an unusual benzoquinone bisnaphthospiroether skeleton, contributing to an expanding category of undiscovered natural products. Their structures and absolute configurations were determined using extensive spectroscopic methods, including NMR, HRESIMS analyses, X-ray single crystal diffraction, as well as through experimental ECD analyses. Biological assays revealed that compounds 1 and 2 exhibited inhibitory activity against A549 cells, with IC50 values of 30.11 ± 3.29 and 34.32 ± 2.66 µM, respectively.

A water mediated multicomponent reaction for the synthesis of novel spirooxindole derivatives and their antifungal activity.

A water mediated three-component reaction of isatin, 4-aminocoumarin, and 1,3-cyclodicarbonyl compounds is reported for the synthesis of spiro[chromeno[4,3-b]cyclopenta[e]pyridine-7,3'-indoline]trione and the spiro[chromeno[4,3-b]quinoline 7,3'-indoline]trione. Up to 27 different spirooxindole derivatives were synthesized by this method. The bioactivity of these spirooxindole derivatives was evaluated and they were found to show antifungal activity against Cercospora arachidicola, Physalospora piricola, Rhizoctonia cerealis, and Fusarium moniliforme.

Unlocking the anticancer activity of gambogic acid: a shift towards ferroptosis via a GSH/Trx dual antioxidant system.

Nuclear factor erythroid 2-related factor 2 (Nrf2) plays a crucial role in ferroptosis by regulating the cellular antioxidant response and maintaining redox balance. However, compounds that induce ferroptosis through dual antioxidant pathways based on Nrf2 have not been fully explored. In our study, we investigated the impact of Gambogic acid (GA) on MCF-7 cells and HepG2 cells in vitro. The cytotoxicity, colony formation assay and cell cycle assay demonstrated potent tumor-killing ability of GA, while its effect was rescued by ferroptosis inhibitors. Furthermore, RNA sequencing revealed the enrichment of ferroptosis pathway mediated by GA. In terms of ferroptosis indicators detection, evidences for GA were provided including reactive oxygen species (ROS) accumulation, alteration in mitochondrial membrane potential (MMP), disappearance of mitochondrial cristae, lipid peroxidation induction, malondialdehyde (MDA) accumulation promotion, iron ion accumulation as well as glutathione (GSH)/thioredoxin (Trx) depletion. Notably, Ferrostatin-1 (Fer-1) and Liproxstatin-1 (Lip-1) successfully rescued GA-induced MDA accumulation. In terms of mechanism, Nrf2 was found to play a pivotal role in GA-induced ferroptosis by inducing protein alterations through the iron metabolism pathway and GSH/Trx dual antioxidant pathway. Furthermore, GA exerted good antitumor activity in vivo through GSH/Trx dual antioxidant pathway, and Fer-1 significantly attenuated its efficacy. In conclusion, our findings first provided new evidence for GA as an inducer of ferroptosis, and Nrf2-mediated GSH/Trx dual antioxidant system played an important role in GA-induced ferroptosis.

Two spirobifluene-based turn-on fluorescent probes for highly selective detection of Cysteine and the applications in cells two-photon fluorescence imaging.

Two spirobifluene-based fluorescent probes SPF1 and SPF2, were designed and synthesized. The probes displayed "turn-on" fluorescence response for Cysteine. One of the challenges in developing a Cysteine probe is to secure high selectivity. SPF1/SPF2 can discriminate Cysteine from GSH as well as Hcy, and showed high substrate selectivity. The detection limit of SPF1 is 36 nM, which is excellent comparing with other optical sensors for Cysteine. The sensing mechanism of SPF1/SPF2 was verified by experimental data and theoretical calculations. There was a good linear relationship between the fluorescence intensity of SPF1/SPF2 and the concentration of Cysteine. The MTT tests indicated that SPF1/SPF2 had low cytotoxicity and good biocompatibility. Theoretical calculations demonstrated that SPF1, SPF2, and their related reaction products with Cysteine exhibited good two-photon absorption properties. Finally, SPF1/SPF2 had been successfully applied to the imaging of Cysteine in living cells under two-photon excitation.

Development of a polarity-sensitive ratiometric fluorescent probe based on the intramolecular reaction of spiro-oxazolidine and its applications for in situ visualizing the fluctuations of polarity during ER stress.

Polarity is a vital element in endoplasmic reticulum (ER) microenvironment, and its variation is closely related to many physiological and pathological activities of ER, so it is necessary to trace fluctuations of polarity in ER. However, most of fluorescent probes for detecting polarity dependent on the changes of single emission, which could be affected by many factors and cause false signals. Ratiometric fluorescent probe with "built-in calibration" can effectively avoid detection errors. Here, we have designed a ratiometric fluorescent probe HM for monitoring the ER polarity based on the intramolecular reaction of spiro-oxazolidine. It forms ring open/closed isomers driven by polarity to afford ratiometric sensing. Probe HM have manifested its ratiometric responses to polarity in spectroscopic results, which could offer much more precise information for the changes of polarity in living cells with the internal built-in correction. It also showed large emission shift ( 133 nm), high selectivity and photo-stability. In biological imaging, HM could selectively accumulate in ER with high photo-stability. Importantly, HM has ability for in situ tracing the changes of ER polarity with ratiometric behavior during the ER stress process with the stimulation of tunicamycin, dithiothreitol and hypoxia, suggesting that HM is an effective molecule tool for monitoring the variations of ER polarity.

Gastrointestinal adverse effects associated with the use of intravenous oliceridine compared with intravenous hydromorphone or fentanyl in acute pain management utilizing adjusted indirect treatment comparison methods.

Background: In the absence of head-to-head comparative data from randomized controlled trials, indirect treatment comparisons (ITCs) may be used to compare the relative effects of treatments versus a common comparator (either placebo or active treatment). For acute pain management, the effects of oliceridine have been compared in clinical trials to morphine but not to fentanyl or hydromorphone. Aim: To assess the comparative safety (specifically differences in the incidence of nausea, vomiting and opioid-induced respiratory depression [OIRD]) between oliceridine and relevant comparators (fentanyl and hydromorphone) through ITC analysis. Methods: A systematic literature review identified randomized clinical trials with oliceridine versus morphine and morphine versus fentanyl or hydromorphone. The ITC utilized the common active comparator, morphine, for the analysis. Results: A total of six randomized controlled trials (oliceridine - 2; hydromorphone - 3; fentanyl - 1) were identified for data to be used in the ITC analyses. The oliceridine data were reported in two studies (plastic surgery and orthopedic surgery) and were also reported in a pooled analysis. The ITC focused on nausea and vomiting due to limited data for OIRD. When oliceridine was compared with hydromorphone in the ITC analysis, oliceridine significantly reduced the incidence of nausea and/or vomiting requiring antiemetics compared with hydromorphone (both orthopedic surgery and pooled data), while results in plastic surgery were not statistically significant. When oliceridine was compared with hydromorphone utilizing data from Hong, the ITC only showed a trend toward reduced risk of nausea and vomiting with oliceridine that was not statistically significant across all three comparisons (orthopedic surgery, plastic surgery and combined). An ITC comparing oliceridine with a study of fentanyl utilizing the oliceridine orthopedic surgery data and combined orthopedic and plastic surgery data showed a trend toward reduced risk that was not statistically significant. Conclusion: In ITC analyses, oliceridine significantly reduced the incidence of nausea and/or vomiting or the need for antiemetics in orthopedic surgery compared with hydromorphone and a non-significant trend toward reduced risk versus fentanyl.

Exacerbated ischemia-reperfusion injury in fatty livers is mediated by lipid peroxidation stress and ferroptosis.

BACKGROUND: Ischemia-reperfusion injury is a common problem in liver surgery and transplantation. Although ischemia-reperfusion injury is known to be more pronounced in fatty livers, the underlying mechanisms for this difference remain poorly understood. We hypothesized that ferroptosis plays a significant role in fatty liver ischemia-reperfusion injury due to increased lipid peroxidation in the presence of stored iron in the fatty liver. To test this hypothesis, the ferroptosis pathway was evaluated in a murine fatty liver ischemia-reperfusion injury model. METHODS: C57BL6 mice were fed with a normal diet or a high fat, high sucrose diet for 12 weeks. At 22 weeks of age, liver ischemia-reperfusion injury was induced through partial (70%) hepatic pedicle clamping for 60 minutes, followed by 24 hours of reperfusion before tissue harvest. Acyl-coenzyme A synthetase long-chain family member 4 and 4-hydroxynonenal were quantified in the liver tissues. In separate experiments, liproxstatin-1 or vehicle control was administered for 7 consecutive days before liver ischemia-reperfusion injury. RESULTS: Exacerbated ischemia-reperfusion injury was observed in the livers of high fat, high sucrose diet fed mice. High fat, high sucrose diet + ischemia-reperfusion injury (HDF+IRI) livers had a significantly greater abundance of acyl-coenzyme A synthetase long-chain family member 4 and 4-hydroxynonenal compared with normal diet + ischemia-reperfusion injury (ND+IRI) livers or sham fatty livers, which indicated an increase of ferroptosis. HFD fed animals receiving liproxstatin-1 injections had a significant reduction in serum aspartate transaminase and alanine transaminase after ischemia-reperfusion injury, consistent with attenuation of ischemia-reperfusion injury in the liver. CONCLUSION: Ferroptosis plays a significant role in ischemia-reperfusion injury in fatty livers. Inhibiting ferroptotic pathways in the liver may serve as a novel therapeutic strategy to protect the fatty liver in the setting of ischemia-reperfusion injury.

New azaspiracid analogues detected as bi-charged ions in Azadinium poporum (Amphidomataceae, Dinophyceae) isolated from Japanese coastal waters.

Lipophilic marine biotoxin azaspiracids (AZAs) are produced by dinoflagellates Azadinium and Amphidoma. Recently, several strains of Azadinium poporum were isolated from Japanese coastal waters, and detailed toxin profiles of two strains (mdd421 and HM536) among them were clarified by several detection techniques on liquid chromatography-tandem mass spectrometry (LC-MS/MS) and liquid chromatography-quadrupole time of flight mass spectrometry (LC-QTOFMS). In our present study, AZA analogues in seven strains of A. poporum from Japanese coastal waters (including two previously reported strains) were determined by these detection techniques. The dominant AZA in the seven strains was AZA2 accompanied by small amounts of several known AZAs and twelve new AZA analogues. Eight of the twelve new AZA analogues discovered in our present study were detected as bi-charged ions on the positive mode LC/MS/MS. This is the first report describing AZA analogues detected as bi-charged ions with hexose and sulfate groups in their structures.

Accraspiroketides A-B, Phenylnaphthacenoid-Derived Polyketides with Unprecedented [6 + 6+6 + 6] + [5 + 5] Spiro-Architecture.

Two novel polyketides, accraspiroketides A (1) and B (2), which feature unprecedented [6 + 6+6 + 6] + [5 + 5] spiro chemical architectures, were isolated from Streptomyces sp. MA37 ΔaccJ mutant strain. Compounds 1-2 exhibit excellent activity against Gram-positive bacteria (MIC = 1.5-6.3 µg/mL). Notably, 1 and 2 have superior activity against clinically isolated Enterococcus faecium K60-39 (MIC = 4.0 µg/mL and 4.7 µg/mL, respectively) than ampicillin (MIC = 25 µg/mL).