Cyclic immonium ion of lactyllysine reveals widespread lactylation in the human proteome.

Lactylation was initially discovered on human histones. Given its nascence, its occurrence on nonhistone proteins and downstream functional consequences remain elusive. Here we report a cyclic immonium ion of lactyllysine formed during tandem mass spectrometry that enables confident protein lactylation assignment. We validated the sensitivity and specificity of this ion for lactylation through affinity-enriched lactylproteome analysis and large-scale informatic assessment of nonlactylated spectral libraries. With this diagnostic ion-based strategy, we confidently determined new lactylation, unveiling a wide landscape beyond histones from not only the enriched lactylproteome but also existing unenriched human proteome resources. Specifically, by mining the public human Meltome Atlas, we found that lactylation is common on glycolytic enzymes and conserved on ALDOA. We also discovered prevalent lactylation on DHRS7 in the draft of the human tissue proteome. We partially demonstrated the functional importance of lactylation: site-specific engineering of lactylation into ALDOA caused enzyme inhibition, suggesting a lactylation-dependent feedback loop in glycolysis.

Chemoproteomic mapping of the glycolytic targetome in cancer cells.

Hyperactivated glycolysis is a metabolic hallmark of most cancer cells. Although sporadic information has revealed that glycolytic metabolites possess nonmetabolic functions as signaling molecules, how these metabolites interact with and functionally regulate their binding targets remains largely elusive. Here, we introduce a target-responsive accessibility profiling (TRAP) approach that measures changes in ligand binding-induced accessibility for target identification by globally labeling reactive proteinaceous lysines. With TRAP, we mapped 913 responsive target candidates and 2,487 interactions for 10 major glycolytic metabolites in a model cancer cell line. The wide targetome depicted by TRAP unveils diverse regulatory modalities of glycolytic metabolites, and these modalities involve direct perturbation of enzymes in carbohydrate metabolism, intervention of an orphan transcriptional protein's activity and modulation of targetome-level acetylation. These results further our knowledge of how glycolysis orchestrates signaling pathways in cancer cells to support their survival, and inspire exploitation of the glycolytic targetome for cancer therapy.

FXR agonists for MASH therapy: Lessons and perspectives from obeticholic acid.

Nonalcoholic fatty liver disease, also called metabolic dysfunction-associated steatotic liver disease, is the most common liver disease worldwide and has no approved pharmacotherapy. Due to its beneficial effects on metabolic regulation, inflammation suppression, cell death prevention, and fibrogenesis inhibition, farnesoid X receptor (FXR) is widely accepted as a promising therapeutic target for nonalcoholic steatosis (NASH) or called metabolic dysfunction-associated steatohepatitis (MASH). Many FXR agonists have been developed for NASH/MASH therapy. Obeticholic acid (OCA) is the pioneering frontrunner FXR agonist and the first demonstrating success in clinical trials. Unfortunately, OCA did not receive regulatory approval as a NASH pharmacotherapy because its moderate benefits did not outweigh its safety risks, which may cast a shadow over FXR-based drug development for NASH/MASH. This review summarizes the milestones in the development of OCA for NASH/MASH and discuss its limitations, including moderate hepatoprotection and the undesirable side effects of dyslipidemia, pruritus, cholelithiasis, and liver toxicity risk, in depth. More importantly, we provide perspectives on FXR-based therapy for NASH/MASH, hoping to support a successful bench-to-clinic transition.

Circ_0008410 contributes to fibroblast-like synoviocytes dysfunction by regulating miR-149-5p/HIPK2 axis.

Circular RNAs (circRNAs) play functional roles in rheumatoid arthritis (RA) progression. Fibroblast-like synoviocytes (RASFs) are the main effectors in RA development. In this study, we explored the function and mechanism of circ_0008410 in RASFs. qRT-PCR was used to detect the expression of circ_0008410, microRNA-149-5p (miR-149-5p), and homeodomain-interacting protein kinase 2 (HIPK2). Cell counting kit-8, EdU assay, flow cytometry, and transwell assay were performed to evaluate cell proliferation, apoptosis, migration, and invasion. Western blot measured the protein levels of related markers and HIPK2. The levels of IL-1ß, TNF-α, and IL-6 were tested by corresponding ELISA kits and Western blot. The combination between miR-149-5p and circ_0008410 or HIPK2 was detected by dual-luciferase reporter assay or RNA immunoprecipitation (RIP) assay. Our data showed that circ_0008410 and HIPK2 were elevated, while miR-149-5p was downregulated in RA synovial tissues and RASFs. Circ_0008410 promoted RASF proliferation, migration, invasion, and inflammation while inhibiting apoptosis. MiR-149-5p was a target of circ_0008410, and its overexpression could reverse the promoting effects of circ_0008410 on RASF dysfunction. Moreover, miR-149-5p could target HIPK2 to suppress RASF proliferation, migration, invasion, and inflammation. Collectively, circ_0008410 promoted RASF dysfunction via miR-149-5p/HIPK2, which might provide a potential target for RA therapy.

Retracted: MD-1 Deficiency Accelerates Myocardial Inflammation and Apoptosis in Doxorubicin-Induced Cardiotoxicity by Activating the TLR4/MAPKs/Nuclear Factor kappa B (NF-κB) Signaling Pathway.

This publication has been retracted by the Editor due to the identification of non-original figure images and manuscript content that raise concerns regarding the credibility and originality of the study and the manuscript. Reference: Ying-Jun Zhang, He Huang, Yu Liu, Bin Kong, Guangji Wang. MD-1 Deficiency Accelerates Myocardial Inflammation and Apoptosis in Doxorubicin-Induced Cardiotoxicity by Activating the TLR4/MAPKs/Nuclear Factor kappa B (NF-kappaB) Signaling Pathway. Med Sci Monit, 2019; 25: 7898-7907. DOI: 10.12659/MSM.919861.

Astilbin protects from sepsis-induced cardiac injury through the NRF2/HO-1 and TLR4/NF-κB pathway.

Cardiac dysfunction and arrhythmia are severe complications of sepsis-induced cardiomyopathy and are associated with an increased risk of morbidity and mortality. Currently, the precise mechanism for sepsis-induced myocardial damage remains unclear. Astilbin, a flavonoid, is reported to have anti-inflammatory, antioxidative, and antiapoptotic properties. However, the effects of astilbin on sepsis-induced cardiomyopathy have not been studied so far. This study aims to investigate the effect of astilbin in sepsis-induced myocardial injury and elucidate the underlying mechanism. In vivo and in vitro sepsis models were created using lipopolysaccharide (LPS) as an inducer in H9C2 cardiomyocytes and C57BL/6 mice, respectively. Our results demonstrated that astilbin reduced myocardial injury and improved cardiac function. Moreover, astilbin prolonged the QT and corrected QT intervals, attenuated myocardial electrical remodeling, and promoted gap junction protein (Cx43) and ion channels expression, thereby reducing the susceptibility of ventricular fibrillation. In addition, astilbin alleviated LPS-induced inflammation, oxidative stress, and apoptosis. Astilbin suppressed the toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB) pathway in vivo and in vitro models. Astilbin remarkedly upregulated the nuclear factor erythroid 2-related factor 2 (NRF2) and heme oxygenase 1 (HO-1) expression. The in vitro treatment with an NRF2 inhibitor reversed the inhibition of the TLR4/NF-κB pathway and antioxidant properties of astilbin. Astilbin attenuated LPS-induced myocardial injury, cardiac dysfunction, susceptibility to VF, inflammation, oxidative stress, and apoptosis by activating the NRF2/HO-1 pathway and inhibiting TLR4/ NF-κB pathway. These results suggest that astilbin could be an effective and promising therapeutics target for the treatment of sepsis-induced cardiomyopathy.

Carnosol prevents cardiac remodeling and ventricular arrhythmias in pressure overload-induced heart failure mice.

Cardiac remodeling is a commonly observed pathophysiological phenomenon associated with the progression of heart failure in various cardiovascular disorders. Carnosol, a phenolic compound extracted from rosemary, possesses noteworthy pharmacological properties including anti-inflammatory, antioxidant, and anti-apoptotic activities. Considering the pivotal involvement of inflammation, oxidative stress, and apoptosis in cardiac remodeling, the present study aims to assess the effects of carnosol on cardiac remodeling and elucidate the underlying mechanisms. In an in vivo model, cardiac remodeling was induced by performing transverse aortic constriction (TAC) surgery on mice, while an in vitro model was established by treating neonatal rat cardiomyocytes (NRCMs) with Ang II. Our results revealed that carnosol treatment effectively ameliorated TAC-induced myocardial hypertrophy and fibrosis, thereby attenuating cardiac dysfunction in mice. Moreover, carnosol improved cardiac electrical remodeling and restored connexin 43 expression, thereby reducing the vulnerability to ventricular fibrillation (VF). Furthermore, carnosol significantly reduced Ang II-induced cardiomyocyte hypertrophy in NRCMs and alleviated the upregulation of hypertrophy and fibrosis markers. Both in vivo and in vitro models of cardiac remodeling exhibited the anti-inflammatory, anti-oxidative, and anti-apoptotic effects of carnosol. Mechanistically, these effects were mediated through the Sirt1/PI3K/AKT pathway, as the protective effects of carnosol were abrogated upon inhibition of Sirt1 or activation of the PI3K/AKT pathway. In summary, our study suggests that carnosol prevents cardiac structural and electrical remodeling by regulating the anti-inflammatory, anti-oxidative, and anti-apoptotic effects mediated by Sirt1/PI3K/AKT signaling pathways, thereby alleviating heart failure and VF.

Identification and Validation of Active Ingredient in Cerebrotein Hydrolysate-I Based on Pharmacokinetic and Pharmacodynamic Studies.

Cerebrotein hydrolysate-1 (CH-1), a mixture of small peptides, polypeptides, and various amino acids derived from porcine brain, has been widely used in the treatment of cerebral injury. However, the bioactive composition and pharmacokinetics of CH-1 are still unexplored because of their complicated composition and relatively tiny amounts in vivo. Herein, NanoLC Orbitrap Fusion Lumos Tribrid Mass Spectrometer was firstly used to qualitatively analyze the components of CH-1. A total of 1347 peptides were identified, of which 43 peptides were characterized by high mass spectrometry (MS) intensity and identification accuracy. We then innovatively synthesized four main peptides for activity verification, and the results suggested that Pep72 (NYEPPTVVPGGDL) had the strongest neuroprotective effect on both in vivo and in vitro models. Next, a quantitative method for Pep72 was established based on liquid chromatography tandem mass spectrometry (LC-MS/MS) with the aid of Skyline software and then used in its pharmacokinetic studies. The results revealed that Pep72 had a high elimination rate and low exposure in rats. In addition, a hCMEC/D3-based in vitro model was built and firstly used to investigate the transport of Pep72. We found that Pep72 had extremely low blood-brain barrier permeability and was not a substrate of efflux transporters. The biotransformation of Pep72 in rat fresh plasma and tissues was investigated to explore the contradiction between pharmacokinetics and efficacy. A total of 11 main metabolites were structurally identified, with PGGDL and EPPTVPGGDL being the main metabolites of Pep72. Notably, metalloproteinase and cysteine protease were confirmed to be the main enzymes mediating Pep72 metabolism in rat tissues. SIGNIFICANCE STATEMENT: The NanoLC Orbitrap Fusion Lumos Tribrid Mass Spectrometer was firstly applied to discover the components of CH-1, and one main peptide Pep72 (NYEPPTVVPGGDL) was innovatively synthesized and firstly found to have the strongest neuroprotective effect among 1347 peptides identified from CH-1. Our study is the first time to identify and verify the active ingredient of CH-1 from the perspective of pharmacokinetics and pharmacodynamics, and provides a systematic technical platforms and strategies for the active substance research of other protein hydrolysates.

Design, synthesis, and biological evaluation of deuterated indolepropionic acid derivatives as novel long-acting pan PPARα/γ/δ agonists.

Metabolic syndrome is a complex disease with diverse symptoms, but current pharmacological interventions have limited efficacy. Indeglitazar, a pan-agonist targeting the three-peroxisome proliferator activated receptors (PPAR), exhibits significant therapeutic effects on both diabetic and fatty liver animal models. However, its short half-life limits the in vivo efficacy, which might be attributed to the ß-oxidation of indolepropionic acid at Indeglitazar. To overcome this metabolic instability, two deuterium atoms were introduced to the α-position of indolepropionic acid to block the ß-oxidation. In this study, several deuterated derivatives were found to sustain PPARs activity and extend the half-life of liver microsomes. In oral glucose tolerance tests, I-1 exhibited the strongest glucose-lowering effect on ob/ob mice in this series. In db/db mice, I-1 reduced lipid levels, liver steatosis and promoted UCP1 expression in white adipose tissue. Mechanistic studies further revealed that I-1 exerts stronger effects than Indeglitazar on the regulation of genes related to lipid metabolism, mitochondrial function, and oxidative stress. Furthermore, I-1 significantly reduced liver steatosis, hepatocellular ballooning, inflammation, and fibrosis in NASH model induced by HFD + CCl4, and even exerted better therapeutic effect than that of Indeglitazar. With the above attractive efficacy, deuterated derivative I-1 is considered as a promising treatment for metabolic syndrome.

Gremlin-1 promotes IL-1ß-stimulated chondrocyte inflammation and extracellular matrix degradation via activation of the MAPK signaling pathway.

The role and mechanism of Gremlin-1 in osteoarthritis (OA) were expected to be probed in this study. Firstly, an in vitro OA model was constructed by stimulating human chondrocyte cell line CHON-001 with IL-1ß. Next, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) were utilized for assessing the effect of IL-1ß with different concentrations (5, 10, and 20 ng/mL) on the activity and Gremlin-1 messenger RNA of CHON-001 cells, respectively. Besides, the influence of knocking down/over-expressing Gremlin-1 on the inflammatory factors (IL-6, TNF-α, IL-18 and PGE2), oxidative stress-related substances (malondialdehyde [MDA]; superoxide dismutase [SOD]; lactate dehydrogenase [LDH]), extracellular matrix (ECM) degradation-related proteins, and mitogen-activated protein kinase (MAPK) pathway proteins in IL-1ß-stimulated CHON-001 cells were tested by enzyme-linked immunosorbent assay, related kits, qRT-PCR, and western blot, respectively. IL-1ß inhibited CHON-001 cell proliferation and upregulated Gremlin-1 expression in a concentration-dependent manner. Overexpression of Gremlin-1 increased the IL-6, TNF-α, IL-18, PGE2, and MDA levels, enhanced the LDH activity, and decreased the SOD activity in IL-1ß-induced CHON-001 cells; while the effect of Gremlin-1 knockdown on the above factors was in contrast with that of the overexpression. Furthermore, overexpression of Gremlin-1 upregulated protein expression of matrix metalloproteinase (MMP)-3, MMP-13, and ADAMTS4 while downregulated protein expression of collagen III, aggrecan, and SOX-9 in IL-1ß-stimulated CHON-001 cells. Besides, overexpression of Gremlin-1 increased the p-p38/p38 value while decreased the p-JNK/JNK value in L-1ß-stimulated CHON-001 cells; however, knockdown of Gremlin-1 reversed the above results. Gremlin-1 may promote IL-1ß-stimulated CHON-001 cell inflammation and ECM degradation by activating the MAPK signaling pathway.

Silybin regulates P450s activity by attenuating endoplasmic reticulum stress in mouse nonalcoholic fatty liver disease.

Cytochrome P450s are important phase I metabolic enzymes located on endoplasmic reticulum (ER) involved in the metabolism of endogenous and exogenous substances. Our previous study showed that a hepatoprotective agent silybin restored CYP3A expression in mouse nonalcoholic fatty liver disease (NAFLD). In this study we investigated how silybin regulated P450s activity during NAFLD. C57BL/6 mice were fed a high-fat-diet (HFD) for 8 weeks to induce NAFLD, and were administered silybin (50, 100 mg ·kg-1 ·d-1, i.g.) in the last 4 weeks. We showed that HFD intake induced hepatic steatosis and ER stress, leading to significant inhibition on the activity of five primary P450s including CYP1A2, CYP2B6, CYP2C19, CYP2D6, and CYP3A in liver microsomes. These changes were dose-dependently reversed by silybin administration. The beneficial effects of silybin were also observed in TG-stimulated HepG2 cells in vitro. To clarify the underlying mechanism, we examined the components involved in the P450 catalytic system, membrane phospholipids and ER membrane fluidity, and found that cytochrome b5 (cyt b5) was significantly downregulated during ER stress, and ER membrane fluidity was also reduced evidenced by DPH polarization and lower polyunsaturated phospholipids levels. The increased ratios of NADP+/NADPH and PC/PE implied Ca2+ release and disruption of cellular Ca2+ homeostasis resulted from mitochondria dysfunction and cytochrome c (cyt c) release. The interaction between cyt c and cyt b5 under ER stress was an important reason for P450s activity inhibition. The effect of silybin throughout the whole course suggested that it regulated P450s activity through its anti-ER stress effect in NAFLD. Our results suggest that ER stress may be crucial for the inhibition of P450s activity in mouse NAFLD and silybin regulates P450s activity by attenuating ER stress.

Dose-dependent pharmacokinetics of midazolam in rats: influence of hepatic first-pass metabolism.

To characterise the dose-dependent pharmacokinetics of midazolam and evaluate the intestinal and hepatic first-pass effects on midazolam in Sprague-Dawley rats, the concentrations and area under the concentration-time curve (AUC) of midazolam in the portal and systemic plasma were simultaneously determined with a double cannulation method.It was found that about 75% of the dose was left in the portal blood with different oral administration doses, while the bioavailability in the liver was 37.86% at 20 mg/kg, significantly higher than 9.16% at 2 mg/kg.The disproportional increase in AUC of midazolam and significant decrease in exposure of metabolites were observed in systemic plasma after hepatic portal vein administration. And in the in vitro study, the formation rate of the metabolites of midazolam significantly decreased when midazolam was at 300 µM compared with 100 µM.These results indicated that not only the saturation of first-pass metabolism but also the inhibition of hepatic metabolism is responsible for the nonlinear PK of midazolam. Thus, a rational dose should be chosen when midazolam is used as a probe in the drug-drug interaction study, particularly for orally administered drugs that undergo hepatic first-pass metabolism.

Loss of MD1 Promotes Inflammatory and Apoptotic Atrial Remodelling in Diabetic Cardiomyopathy by Activating the TLR4/NF-κB Signalling Pathway.

INTRODUCTION: Myeloid differentiation protein 1 (MD1), a negative regulator of toll-like receptor 4 (TLR4), is widely expressed in the heart. Recent studies have shown that MD1 plays an important role in cardiac remodelling. However, the effects and potential mechanisms underlying MD1-mediated atrial remodelling in diabetic cardiomyopathy (DCM) remain unclear. Therefore, this study was designed to explore the role of MD1 in DCM-related atrial remodelling. METHODS: MD1 knockout (MD1-KO) mice and wild-type (WT) littermates were injected with streptozotocin (STZ) to establish a diabetic mouse model. These mice were then used to evaluate MD1 expression and its effects on atrial remodelling in vivo. RESULTS: MD1 expression was significantly decreased in STZ-induced diabetic mice. The loss of MD1 aggravated atrial fibrosis, inflammation, and apoptosis in DCM mice and promoted atrial remodelling. MD1-KO diabetic mice also showed higher susceptibility to atrial fibrillation (AF) and worse cardiac function. Mechanistically, the deletion of MD1 promoted the activation of the TLR4/NF-κB signalling pathway, resulting in atrial remodelling in DCM mice via increased p65 phosphorylation. CONCLUSIONS: The deletion of MD1 plays an important role in inflammatory and apoptotic atrial remodelling and increases susceptibility to AF in DCM mice, providing a new target for the preventive treatment of DCM-related atrial remodelling.

The Effect of Endogenous PARP-1 in Different Phases of IL-1ß-Induced Chondrocyte Degeneration.

Objective: Poly (ADP-ribose) polymerase-1 (PARP-1) is a regulatory enzyme involved in DNA damage repair, gene transcription, cell growth, death and apoptosis. In our study, we aimed to explore the dynamic role of PARP-1 in chondrocyte (CH) degeneration in vitro. Methods: We used the primary CHs and treated them with interleukin-1 beta for up to 5 days. (IL-1ß) to induce degeneration. Meanwhile, we used AG-14361 (AG) to inhibit endogenous PARP-1 expression. Cell survival and collagen II expression were used to define the cell function of CHs. In addition, other metabolic indicators were measured containing the reactive oxygen species (ROS) level, 8-Hydroxy-2'-deoxyguanosine (8-OH-dG), IL-1ß, tumor necrosis factor alpha (TNF-α) and caspase 3/9 expression. Results: With IL-1ß treatment, the PARP1 expression of CHs was gradually increased from day 1 to day 5, accompanied by a reduction in cell survival and collagen II expression, and an increase in ROS, 8-OH-dG, IL-1ß, TNF-α and caspase 3/9 levels. We suppressed PARP1 expression on the first day of IL-1ß stimulation and found severe destruction of cell survival and collagen II content with a higher expression of caspase 3/9. However, when we cultured the CHs with AG from day 3 of the 5-day IL-1ß stimulation, cell survival and collagen II expression were rescued, and the ROS, 8-OH-dG, IL-1ß, TNF-α, and caspase 3/9 were downregulated. Conclusions: On day 1 of degeneration, increased PARP-1 played a protective role in CHs. However, from days 3 to 5 of degeneration, the accumulated PARP-1 presented a more destructive function in CHs.

Selective Photoaffinity Probe for Monitoring Farnesoid X Receptor Expression in Cultured Cells.

Farnesoid X receptor (FXR), a member of the nuclear receptor superfamily, is a vital ligand-activated transcriptional factor, which is highly expressed in the liver, intestine, and adrenal gland. However, FXR homeostasis is influenced by many factors, such as diet and circadian rhythm, and the expression of FXR differs in diverse organs. Currently, there is no method to monitor the FXR homeostasis in real time, which restricts us from further investigating the function of FXR under physiological and pathological conditions. In this project, classic FXR agonists were selected to be modified to targeting FXR. The photo-cross-linking diazirine group and alkynyl, a click reaction group, were incorporated to the ligands. Through biorthogonal reaction, fluorophore was linked to the ligands to realize the monitoring of FXR expression in cells.

Feasibility of in vivo CAR T cells tracking using streptavidin-biotin-paired positron emission tomography.

BACKGROUND: A novel reporter system, streptavidin (SA)- [68 Ga]Ga-labeled biotin ([68 Ga]Ga-DOTA-biotin), was constructed and its ability for PET imaging the behaviors of CAR T cells were also evaluated in this study. METHODS: In vitro activity and cytotoxicity of the SA transduced anti-CD19-CAR T (denoted as SA-CD19-CAR T) cells were determined. The feasibility of monitoring proliferation profiles of SA-CD19-CAR T cells using [68 Ga]Ga-DOTA-biotin was firstly investigated in a solid tumor model. Also, the pharmacodynamics and pharmacokinetics of the CAR T cells in whole-body hematologic neoplasms were evaluated by bioluminescence imaging and [68 Ga]Ga-DOTA-biotin PET imaging simultaneously. RESULTS: After transduction with SA, the activity and cytotoxicity of the modified CAR T cells were not affected. PET images revealed that the uptakes of [68 Ga]Ga-DOTA-biotin in CD19+ K562 solid tumors were 0.67 ± 0.32 ID%/g and 1.26 ± 0.13 ID%/g at 30 min and 96 h p.i. after administration of SA-CD19-CAR T cells respectively. It confirmed that the SA-CD19-CAR T cells could effectively inhibit the growth of Raji hematologic tumors. However, low radioactivity related to the proliferation of CD19-CAR T cells was detected in the Raji model. CONCLUSION: SA-CD19-CAR T cells were constructed successfully without disturbing the antitumor functions of the cells. The proliferation of the CAR T cells in solid tumors could be early detected by [68 Ga]Ga-DOTA-biotin PET imaging.

Peroxynitrite-Promoted Persulfide Prodrugs with Protective Potential against Paracetamol Poisoning.

The newly emerging persulfide prodrugs provide additional options for the profound study of persulfide, a fascinating molecule expected to intervene in biological functions and even diseases. Peroxynitrite is often the culprit in pathological processes characterized by oxidative stress, while the persulfide prodrug responsive to it is still pending. To enrich the family of redox-activated prodrugs, we designed prodrugs with a 2-oxo-2-phenylacetamide trigger, which achieved the release of persulfide via 1, 6-N, S-relay. The degradation of prodrugs and the formation of persulfides were confirmed to be peroxynitrite-responsible by the qualitative and quantitative studies based on LC-MS/MS methods and a spectrophotometry-based tag-switch strategy. Furthermore, these prodrugs showed potent peroxynitrite scavenging activity, cellular therapeutic potential against paracetamol poisoning in HepG2 and oxidative stress in H9c2, as well as desirable in vitro metabolic properties.

Bacteroides species differentially modulate depression-like behavior via gut-brain metabolic signaling.

Gut microbiome disturbances have been widely implicated in major depressive disorder (MDD), although the identity of causal microbial species and the underlying mechanisms are yet to be fully elucidated. Here we show that Bacteroides species enriched in the gut microbiome from MDD patients differentially impact the susceptibility to depressive behaviors. Transplantation of fecal microbiome from MDD patients into antibiotic-treated mice induced anxiety and despair-like behavior and impaired hippocampal neurogenesis. Colonization of Bacteroides fragilis, Bacteroides uniformis, and, to a lesser extent, Bacteroides caccae, but not Bacteroides ovatus, recapitulated the negative effects of MDD microbiome on behavior and neurogenesis. The varying impacts of Bacteroides species were partially explained by differential alternations of tryptophan pathway metabolites and neurotransmitters along the gut-brain axis. Notably, an intensified depletion of cerebral serotonin concurred with the enhanced susceptibility to depression. Together, these findings identify select Bacteroidetes species that contribute to depression susceptibility in mice by metabolic regulation along the gut-brain axis.

Therapeutic targeting of glutamate dehydrogenase 1 that links metabolic reprogramming and Snail-mediated epithelial-mesenchymal transition in drug-resistant lung cancer.

Acquired drug resistance and epithelial-mesenchymal transition (EMT) mediated metastasis are two highly interacting determinants for non-small-cell lung cancer (NSCLC) prognosis. This study investigated the common mechanisms of drug resistance and EMT from the perspective of metabolic reprogramming, which may offer new ideas to improve anticancer therapy. Acquired resistant cells were found to grow faster and have a greater migratory and invasive capacity than their parent cells. Metabolomics analysis revealed that acquired resistant cells highly relied on glutamine utilization and mainly fluxed into oxidative phosphorylation energy production. Further mechanistic studies screened out glutamate dehydrogenase 1 (GLUD1) as the determinant of glutamine addiction in acquired resistant NSCLC cells, and provided evidence that GLUD1-mediated α-KG production and the accompanying reactive oxygen species (ROS) accumulation primarily triggered migration and invasion by inducing Snail. Pharmacological and genetic interference with GLUD1 in vitro significantly reversed drug resistance and decreased cell migration and invasion capability. Lastly, the successful application of R162, a selective GLUD1 inhibitor, to overcome both acquired resistance and EMT-induced metastasis in vivo, identified GLUD1 as a promising and druggable therapeutic target for malignant progression of NSCLC. Collectively, our study offers a potential strategy for NSCLC therapy, especially for drug-resistant patients with highly expressed GLUD1.

Exogenous glutathione exerts a therapeutic effect in ischemic stroke rats by interacting with intrastriatal dopamine.

We previously showed that oral administration of exogenous glutathione (GSH) exerted a direct and/or indirect therapeutic effect on ischemic stroke rats, but the underlying mechanisms remain elusive. In the current study, we conducted a quantitative proteomic analysis to explore the pathways mediating the therapeutic effect of GSH in cerebral ischemia/reperfusion (I/R) model rats. Rats were subjected to middle cerebral artery occlusion (MCAO) for 2 h followed by reperfusion. The rats were treated with GSH (250 mg/kg, ig) or levodopa (L-dopa, 100 mg/kg, ig) plus carbidopa (10 mg/kg, ig). Neurologic deficits were assessed, and the rats were sacrificed at 24 h after cerebral I/R surgery to measure brain infarct sizes. We conducted a proteomic analysis of the lesion side striatum samples and found that tyrosine metabolism and dopaminergic synapse were involved in the occurrence of cerebral stroke and the therapeutic effect of GSH. Western blot assay revealed that tyrosine hydroxylase (TH) mediated the occurrence of I/R-induced ischemic stroke and the therapeutic effect of GSH. We analyzed the regulation of GSH on endogenous small molecule metabolites and showed that exogenous GSH had the most significant effect on intrastriatal dopamine (DA) in I/R model rats by promoting its synthesis and inhibiting its degradation. To further explore whether DA-related alterations were potential targets of GSH, we investigated the therapeutic effect of DA accumulation on ischemic brain injury. The combined administration of the precursor drugs of DA (L-dopa and carbidopa) significantly ameliorated neurological deficits, reduced infarct size, and oxidative stress, and decreased pro-inflammatory cytokines levels in the striatum of I/R injury rats. More interestingly, exogenous L-dopa/carbidopa could also greatly enhance the exposure of intracerebral GSH by upregulating GSH synthetases and enhancing homocysteine (HCY) levels in the striatum. Thus, administration of exogenous GSH exerts a therapeutic effect on ischemic stroke by increasing intrastriatal DA, and the accumulated DA can, in turn, enhance the exposure of GSH and its related substances, thus promoting the therapeutic effect of GSH.