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1.
iScience ; 27(10): 110911, 2024 Oct 18.
Article in English | MEDLINE | ID: mdl-39351192

ABSTRACT

Lysine lactylation (Kla), an epigenetic mark triggered by lactate during glycolysis, including the Warburg effect, bridges metabolism and gene regulation. Enzymes such as p300 and HDAC1/3 have been pivotal in deciphering the regulatory dynamics of Kla, though questions about additional regulatory enzymes, their specific Kla substrates, and the underlying functional mechanisms persist. Here, we identify SIRT1 and SIRT3 as key "erasers" of Kla, shedding light on their selective regulation of both histone and non-histone proteins. Proteomic analysis in SIRT1/SIRT3 knockout HepG2 cells reveals distinct substrate specificities toward Kla, highlighting their unique roles in cellular signaling. Notably, we highlight the role of specific Kla modifications, such as those on the M2 splice isoform of pyruvate kinase (PKM2), in modulating metabolic pathways and cell proliferation, thereby expanding Kla's recognized functions beyond epigenetics. Therefore, this study deepens our understanding of Kla's functional mechanisms and broadens its biological significance.

2.
Chembiochem ; : e202400559, 2024 Sep 19.
Article in English | MEDLINE | ID: mdl-39299917

ABSTRACT

Profiling the substrate sequence preferences of proteases is important for understanding both biological functions as well as for designing protease inhibitors. Several methods are available for profiling the sequence specificity of proteases. However, there is currently no rapid and high-throughput method to profile specificity of proteases for noncanonical substrates. In this study, we described a strategy to use a DNA-encoded noncanonical substrate library to identify the protease substrates composed of both canonical and noncanonical amino acids. This approach uses a DNA-encoded peptide library and introduces a biotin molecule at the N-terminus to immobilize the library on a solid support. Upon protease hydrolysis, the released DNA tag of the substrate peptides can be sequenced to identify the substrate structures. Using this approach, we profiled trypsin and fibroblast activation protein α and discovered noncanonical substrates that were more efficiently cleaved than the commonly used substrates. The identified substrates of FAP were further used to design corresponding covalent inhibitors containing non-canonical sequences with high potency for the target protease. Overall, our approach can aid in the development of new protease substrates and inhibitors.

3.
Acta Pharmacol Sin ; 2024 Sep 30.
Article in English | MEDLINE | ID: mdl-39349767

ABSTRACT

Depressive disorders are a global mental health challenge that is closely linked to inflammation, especially in the post-COVID-19 era. The JAK-STAT pathway, which is primarily associated with inflammatory responses, is not fully characterized in the context of depressive disorders. Recently, a phase 3 retrospective cohort analysis heightened that the marketed JAK inhibitor tofacitinib is beyond immune diseases and has potential for preventing mood disorders. Inspired by these clinical facts, we investigated the role of the JAK-STAT signaling pathway in depression and comprehensively assessed the antidepressant effect of tofacitinib. We found that aberrant activation of the JAK-STAT pathway is highly conserved in the hippocampus of classical depressive mouse models: LPS-induced and chronic social defeat stress (CSDS)-induced depressive mice. Mechanistically, the JAK-STAT pathway mediates proinflammatory cytokine production and microgliosis, leading to synaptic defects in the hippocampus of both depressive models. Remarkably, the JAK inhibitor tofacitinib effectively reverses these phenomena, contributing to its antidepressant effect. These findings indicate that the JAK/STAT pathway could be implicated in depressive disorders, and suggest that the JAK inhibitor tofacitinib has a potential translational implication for preventing mood disorders far beyond its current indications.

5.
J Ethnopharmacol ; : 118780, 2024 Sep 09.
Article in English | MEDLINE | ID: mdl-39260706

ABSTRACT

ETHNOPHARMACOLOGICAL RELEVANCE: Sepsis-induced acute lung injury (ALI) presents with significant morbidity and mortality in clinical settings. Tanreqing Injection (TRQI) has been clinically recommended for the treatment of ALI; however, the specific active chemical constituents remain unidentified. AIM OF THE STUDY: This study aimed to elucidate the potential pharmacologically active components and the underlying mechanisms of TRQI in the treatment of sepsis-induced ALI. MATERIALS AND METHODS: High-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) techniques were employed to identify the effective chemical constituents of TRQI. Additionally, an in vitro study was conducted using Raw264.7 macrophage cells stimulated with lipopolysaccharide (LPS) to evaluate the inhibitory effects of TRQI. An acute lung injury model produced by LPS was intraperitoneal injection in mice to assess the ALI-inhibitory effect of TRQI. The lung's pathological characteristics were examined using hematoxylin and eosin staining. Enzyme-linked immunosorbent assay (ELISA) and QPCR were performed to confirm the pharmaceutical effect. Network pharmacology was employed for mechanistic exploration, incorporating GO, and PPI analyses of targets. Src inhibitor and JNK agonist used to investigate the dependence of associated signaling pathways. RESULTS: Combining pharmacokinetic characteristics, lung first-pass effect and anti-inflammatory effects, the main components of TRQI for treating sepsis induced ALI were narrowed down to seven compounds: chlorogenic acid, scutellarin, wogonoside, oroxyloside, oroxylin A and baicalein. Network pharmacology indicated that Src/JNK signaling pathway, may be the main regulatory pathway for treatment of actue lung injury. Next by using Src inhibitor, Src inhibition partly diminished the protective effects of TRQI in LPS-injected mice. Pretreatment with JNK agonist anisomycin abolished the protective effects of lung injury in vivo. CONCLUSIONS: TRQI is injected, the seven compounds could be presented in vivo, which can improve ALI by inhibiting Src-JNK signaling.

6.
Chem Biodivers ; : e202401520, 2024 Sep 02.
Article in English | MEDLINE | ID: mdl-39221607

ABSTRACT

A previously undescribed triterpenoid (fortunefuroic acid J, 1) was isolated from the endangered conifer Keteleeria hainanensis, along with 20 other known terpenoids. Compound 1 is characterized by an unusual 3,4-seco-9ßH-lanost-3-oic acid motif, featuring a rare furoic acid moiety in its lateral chain. The structure elucidation of this compound was achieved through a combination of spectroscopic and computational methods. The C-15 epimers of 15-methoxypinusolidic acid (15R-8 and 15S-9) were successfully separated and identified for the first time. Compound 1 demonstrated dual inhibitory effects against ATP-citrate lyase (ACL, IC50: 0.92 µM) and acetyl-CoA carboxylase 1 (ACC1, IC50: 10.76 µM). Compounds 2 and 11 exclusively inhibited ACL, exhibiting IC50 values of 2.64 and 6.35 µM, respectively. Compound 1 is classified among the fortunefuroic acid-type compounds, previously isolated from K. fortunei, distinguished by the presence of a rare furoic acid moiety in their lateral chain. The chemotaxonomic significance of the 9ßH-lanost-26-oic acids in Keteleeria was briefly discussed. These findings highlight the importance of conserving plant species diversity, thereby enhancing the exploration of structurally diverse compounds and potential avenues for developing new therapeutics targeting ACL/ACC1-associated diseases.

7.
Phytochemistry ; 228: 114259, 2024 Dec.
Article in English | MEDLINE | ID: mdl-39186996

ABSTRACT

A comprehensive phytochemical investigation of the flower buds and leaves/twigs of Heptacodium miconioides, a cultivated ornamental plant native to China and categorized as 'vulnerable', has led to the isolation of 45 structurally diverse compounds, which comprise 18 phenylpropanoids (1-4, 7-20), 11 pentacyclic triterpenoids (5, 6, 21-29), eight secoiridoid glycosides (30-37), three quinic acid derivatives (38-40), and a few miscellaneous components (41-45). Among them, (+)-α-intermedianol (1), (+)-holophyllol A (2), and (-)-pseudolarkaemin A (3) represent previously unreported enantiomeric lignans, while (+)-7'(R)-hydroxymatairesinol (4) is an undescribed naturally occurring lignan. Heptacoacids A (5) and B (6) are undescribed 24-nor-urs-28-oic acid derivatives. Their chemical structures were determined by 2D-NMR, supplemented by evidence from specific rotations and circular dichroism spectra. Given the uncertainty surrounding the systematic position of Heptacodium, integrative taxonomy (ITA), a method utilized to define contentious species, is applied. Chemotaxonomy, a vital aspect of ITA, becomes significant. By employing hierarchical clustering analysis (HCA) and syntenic pattern analysis methods, a taxonomic examination based on the major specialized natural products from the flower buds of H. miconioides and two other Caprifoliaceae plants (i.e., Lonicera japonica and Abelia × grandiflora) could offer enhanced understanding of the systematic placement of Heptacodium. Additionally, compounds 39 and 40 displayed remarkable inhibitory activities against ATP-citrate lyase (ACL), with IC50 values of 0.11 and 1.10 µM, respectively. In summary, the discovery of medical properties and refining systematic classification can establish a sturdy groundwork for conservation efforts aimed at mitigating species diversity loss while addressing human diseases.


Subject(s)
Biological Products , Biological Products/chemistry , Biological Products/pharmacology , Biological Products/isolation & purification , Molecular Structure , Endangered Species , Plants, Medicinal/chemistry , Plant Leaves/chemistry
8.
Acta Pharmacol Sin ; 2024 Aug 05.
Article in English | MEDLINE | ID: mdl-39103531

ABSTRACT

Liver fibrosis, one of the leading causes of morbidity and mortality worldwide, lacks effective therapy. The activation of hepatic stellate cells (HSCs) is the dominant event in hepatic fibrogenesis. Luteolin-7-diglucuronide (L7DG) is the major flavonoid extracted from Perilla frutescens and Verbena officinalis. Their beneficial effects in the treatment of liver diseases were well documented. In this study we investigated the anti-fibrotic activities of L7DG and the potential mechanisms. We established TGF-ß1-activated mouse primary hepatic stellate cells (pHSCs) and human HSC line LX-2 as in vitro liver fibrosis models. Co-treatment with L7DG (5, 20, 50 µM) dose-dependently decreased TGF-ß1-induced expression of fibrotic markers collagen 1, α-SMA and fibronectin. In liver fibrosis mouse models induced by CCl4 challenge alone or in combination with HFHC diet, administration of L7DG (40, 150 mg·kg-1·d-1, i.g., for 4 or 8 weeks) dose-dependently attenuated hepatic histopathological injury and collagen accumulation, decreased expression of fibrogenic genes. By conducting target prediction, molecular docking and enzyme activity detection, we identified L7DG as a potent inhibitor of protein tyrosine phosphatase 1B (PTP1B) with an IC50 value of 2.10 µM. Further studies revealed that L7DG inhibited PTP1B activity, up-regulated AMPK phosphorylation and subsequently inhibited HSC activation. This study demonstrates that the phytochemical L7DG may be a potential therapeutic candidate for the treatment of liver fibrosis.

9.
ACS Med Chem Lett ; 15(7): 1102-1108, 2024 Jul 11.
Article in English | MEDLINE | ID: mdl-39015265

ABSTRACT

α-Galactosylceramide (KRN7000 or α-GalCer) analogues terminated with phenyl (Ph) groups at the acyl moiety possess more potency than KRN7000 to activate invariant natural killer T (iNKT) cells for inducing a T helper 1 (Th1)-biased immune response. However, biological activities of phenyl glycolipids with thio-modifications at the acyl moiety remain unknown, and facile approaches for highly stereoselective synthesis of KRN7000 and its analogues are rather scarce. Herein, we exploited 4,6-di-O-tert-butylsilylene (DTBS)-directed stereospecific galactosylation to efficiently synthesize various α-GalCer analogues bearing thioamide, terminal thiophenyl and dual modifications at the acyl moiety. Biological evaluations suggest that a new analogue S34 featuring a terminal Ph-S-Ph-F group exhibits a more superior Th1-biased immune response in mice. Molecular docking analysis revealed that the introduction of a sulfur atom influences vital hydrogen bonding interactions between glycolipids and the cluster of differentiation 1d (CDld), thus adjusting the stability of the glycolipid-CDld complex.

10.
Cell Commun Signal ; 22(1): 364, 2024 Jul 17.
Article in English | MEDLINE | ID: mdl-39014433

ABSTRACT

BACKGROUND: Chronic obstructive pulmonary disease (COPD) remains a leading cause of morbidity and mortality worldwide, characterized by persistent respiratory symptoms and airflow limitation. The involvement of C-C motif chemokine ligand 2 (CCL2) in COPD pathogenesis, particularly in macrophage regulation and activation, is poorly understood despite its recognized role in chronic inflammation. Our study aims to elucidate the regulatory role and molecular mechanisms of CCL2 in the pathogenesis of COPD, providing new insights for therapeutic strategies. METHODS: This study focused on the CCL2-CCR2 signaling pathway, exploring its role in COPD pathogenesis using both Ccl2 knockout (KO) mice and pharmacological inhibitors. To dissect the underlying mechanisms, we employed various in vitro and in vivo methods to analyze the secretion patterns and pathogenic effects of CCL2 and its downstream molecular signaling through the CCL2-CCR2 axis. RESULTS: Elevated Ccl2 expression was confirmed in the lungs of COPD mice and was associated with enhanced recruitment and activation of macrophages. Deletion of Ccl2 in knockout mice, as well as treatment with a Ccr2 inhibitor, resulted in protection against CS- and LPS-induced alveolar injury and airway remodeling. Mechanistically, CCL2 was predominantly secreted by bronchial epithelial cells in a process dependent on STAT1 phosphorylation and acted through the CCR2 receptor on macrophages. This interaction activated the PI3K-AKT signaling pathway, which was pivotal for macrophage activation and the secretion of inflammatory cytokines, further influencing the progression of COPD. CONCLUSIONS: The study highlighted the crucial role of CCL2 in mediating inflammatory responses and remodeling in COPD. It enhanced our understanding of COPD's molecular mechanisms, particularly how CCL2's interaction with the CCR2 activates critical signaling pathways. Targeting the CCL2-CCR2 axis emerged as a promising strategy to alleviate COPD pathology.


Subject(s)
Chemokine CCL2 , Macrophages , Mice, Knockout , Phosphatidylinositol 3-Kinases , Proto-Oncogene Proteins c-akt , Pulmonary Disease, Chronic Obstructive , Receptors, CCR2 , Signal Transduction , Pulmonary Disease, Chronic Obstructive/metabolism , Pulmonary Disease, Chronic Obstructive/pathology , Animals , Chemokine CCL2/metabolism , Chemokine CCL2/genetics , Receptors, CCR2/metabolism , Receptors, CCR2/genetics , Proto-Oncogene Proteins c-akt/metabolism , Signal Transduction/drug effects , Phosphatidylinositol 3-Kinases/metabolism , Macrophages/metabolism , Macrophages/drug effects , Mice , Humans , Mice, Inbred C57BL , Male
12.
J Med Chem ; 67(15): 12760-12783, 2024 Aug 08.
Article in English | MEDLINE | ID: mdl-39072488

ABSTRACT

SARS-CoV-2 has still been threatening global public health with its emerging variants. Our previous work reported lead compound JZD-07 that displayed good 3CLpro inhibitory activity. Here, an in-depth structural optimization for JZD-07 was launched to obtain more desirable drug candidates for the therapy of SARS-CoV-2 infection, in which 54 novel derivatives were designed and synthesized by a structure-based drug design strategy. Among them, 24 compounds show significantly enhanced 3CLpro inhibitory potencies with IC50 values less than 100 nM, and 11 compounds dose-dependently inhibit the replication of the SARS-CoV-2 delta variant. In particular, compound 49 has the most desirable antiviral activity with EC50 of 0.272 ± 0.013 µM against the delta variant, which was more than 20 times stronger than JZD-07. Oral administration of 49 could significantly reduce the lung viral copies of mice, exhibiting a more favorable therapeutic potential. Overall, this investigation presents a promising drug candidate for further development to treat SARS-CoV-2 infection.


Subject(s)
Antiviral Agents , COVID-19 Drug Treatment , Coronavirus 3C Proteases , SARS-CoV-2 , SARS-CoV-2/drug effects , Antiviral Agents/pharmacology , Antiviral Agents/chemistry , Antiviral Agents/chemical synthesis , Animals , Coronavirus 3C Proteases/antagonists & inhibitors , Coronavirus 3C Proteases/metabolism , Mice , Humans , Structure-Activity Relationship , Drug Discovery , Virus Replication/drug effects , Vero Cells , Chlorocebus aethiops , Drug Design , Small Molecule Libraries/pharmacology , Small Molecule Libraries/chemistry , Small Molecule Libraries/chemical synthesis , Molecular Docking Simulation
13.
Chem Commun (Camb) ; 60(63): 8240-8243, 2024 Aug 01.
Article in English | MEDLINE | ID: mdl-39007923

ABSTRACT

O-GlcNAcase (OGA) is implicated in several important biological and disease-relevant processes. Here, we synthesized fluorogenic probes for OGA by grafting GlcNAc directly or using a self-immolative linker to the hydroxyl position of 4-hydroxylisoindoline (BHID), a typical excited-state intramolecular proton transfer (ESIPT) probe. The probe was used for a fluorogenic assay to determine the half maximal inhibitory concentration of a known OGA inhibitor and differentiate between OGA and hexosaminidase when GlcNAc is replaced by GlcNPr, where a propionyl group is used instead of an acetyl group.


Subject(s)
Fluorescent Dyes , Isoindoles , Fluorescent Dyes/chemistry , Fluorescent Dyes/chemical synthesis , Isoindoles/chemistry , Isoindoles/chemical synthesis , Humans , beta-N-Acetylhexosaminidases/metabolism , beta-N-Acetylhexosaminidases/antagonists & inhibitors , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , Enzyme Inhibitors/chemical synthesis , Molecular Structure , Spectrometry, Fluorescence
14.
Phytochemistry ; 226: 114221, 2024 Oct.
Article in English | MEDLINE | ID: mdl-39002688

ABSTRACT

An extensive phytochemical investigation on the EtOAc-soluble fraction of the 90% MeOH extract from the twigs and needles of the 'vulnerable' Chinese endemic conifer Tsuga forrestii (Forrest's hemlock) led to the isolation and characterization of 50 structurally diverse diterpenoids, including 15 unreported C-18 carboxylated ones (tsugaforrestiacids A-O, 1-15, resp.). Among them, compounds 1-7 are abieten-18-oic acids, compound 8 is an abieten-18-succinate, and compounds 10-12 are podocarpen-18-oic acids, whereas compounds 13-15 are pimarane-type, isopimarane-type, and totarane-type diterpenoid acids, respectively. Their structures and absolute configurations were determined by a combination of spectroscopic methods, GIAO NMR calculations and DP4+ probability analyses, electronic circular dichroism (ECD) data, and single crystal X-ray diffraction analyses. All the isolates were evaluated for their inhibitory activities against the ATP-citrate lyase (ACL), a key enzyme in cellular metabolism. Tsugaforrestiacids E (5) and H (8) were found to have significant inhibitory effects against ACL, with IC50 values of 5.3 and 6.2 µM, respectively. The interactions of the bioactive molecules with the ACL enzyme were examined by molecular docking studies. The isolated diterpenoids also provide chemotaxonomic evidence to support the delimitation of Tsuga from its closest sister group (Nothotsuga). The above findings highlight the importance of protecting plant species with unique and diverse secondary metabolites, which may be potential sources of new therapeutic agents for the treating ACL-associated diseases.


Subject(s)
ATP Citrate (pro-S)-Lyase , Diterpenes , Phytochemicals , Diterpenes/chemistry , Diterpenes/pharmacology , Diterpenes/isolation & purification , ATP Citrate (pro-S)-Lyase/antagonists & inhibitors , ATP Citrate (pro-S)-Lyase/metabolism , Phytochemicals/pharmacology , Phytochemicals/chemistry , Phytochemicals/isolation & purification , China , Molecular Structure , Enzyme Inhibitors/pharmacology , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/isolation & purification , Endangered Species , Molecular Docking Simulation , Structure-Activity Relationship , Plant Leaves/chemistry
15.
Antiviral Res ; 228: 105944, 2024 08.
Article in English | MEDLINE | ID: mdl-38914283

ABSTRACT

SARS-CoV-2 papain-like protease (PLpro) could facilitate viral replication and host immune evasion by respectively hydrolyzing viral polyprotein and host ubiquitin conjugates, thereby rendering itself as an important antiviral target. Yet few noncovalent PLpro inhibitors of SARS-CoV-2 have been reported with improved directed towards pathogenic deubiquitinating activities inhibition. Herein, we report that coronavirus PLpro proteases have distinctive substrate bias and are conserved to deubiquitylate K63-linked polyubiquitination, thereby attenuating host type I interferon response. We identify a noncovalent compound specifically optimized towards halting the K63-deubiquitinase activity of SARS-CoV-2 PLpro, but not other coronavirus (CoV) counterparts or host deubiquitinase. Contrasting with GRL-0617, a SARS-CoV-1 PLpro inhibitor, SIMM-036 is 50-fold and 7-fold (half maximal inhibitory concentration (IC50)) more potent to inhibit viral replication during SARS-CoV-2 infection and restore the host interferon-ß (IFN-ß) response in human angiotensin-converting enzyme 2 (hACE2)-HeLa cells, respectively. Structure-activity relationship (SAR) analysis further reveals the importance of BL2 groove of PLpro, which could determine the selectivity of K63-deubiquitinase activity of the enzyme.


Subject(s)
Antiviral Agents , SARS-CoV-2 , Virus Replication , Humans , SARS-CoV-2/drug effects , SARS-CoV-2/enzymology , Virus Replication/drug effects , Antiviral Agents/pharmacology , Antiviral Agents/chemistry , Coronavirus Papain-Like Proteases/antagonists & inhibitors , Coronavirus Papain-Like Proteases/metabolism , Coronavirus Papain-Like Proteases/chemistry , Coronavirus 3C Proteases/antagonists & inhibitors , Coronavirus 3C Proteases/metabolism , Coronavirus 3C Proteases/chemistry , COVID-19/virology , Deubiquitinating Enzymes/antagonists & inhibitors , Deubiquitinating Enzymes/metabolism , Ubiquitination/drug effects , COVID-19 Drug Treatment , Vero Cells , Chlorocebus aethiops , Protease Inhibitors/pharmacology , Protease Inhibitors/chemistry , Animals , HEK293 Cells
16.
Structure ; 32(9): 1327-1334.e3, 2024 Sep 05.
Article in English | MEDLINE | ID: mdl-38925121

ABSTRACT

The coronavirus disease 2019 (COVID-19) is caused by a novel coronavirus called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which spreads rapidly all over the world. The main protease (Mpro) is significant to the replication and transcription of viruses, making it an attractive drug target against coronaviruses. Here, we introduce a series of novel inhibitors which are designed de novo through structure-based drug design approach that have great potential to inhibit SARS-CoV-2 Mproin vitro. High-resolution structures show that these inhibitors form covalent bonds with the catalytic cysteine through the novel dibromomethyl ketone (DBMK) as a reactive warhead. At the same time, the designed phenyl group beside the DBMK warhead inserts into the cleft between H41 and C145 through π-π stacking interaction, splitting the catalytic dyad and disrupting proton transfer. This unique binding model provides novel clues for the cysteine protease inhibitor development of SARS-CoV-2 as well as other pathogens.


Subject(s)
Antiviral Agents , Coronavirus 3C Proteases , Drug Design , Protease Inhibitors , Protein Binding , SARS-CoV-2 , SARS-CoV-2/enzymology , SARS-CoV-2/drug effects , SARS-CoV-2/metabolism , Coronavirus 3C Proteases/antagonists & inhibitors , Coronavirus 3C Proteases/metabolism , Coronavirus 3C Proteases/chemistry , Protease Inhibitors/chemistry , Protease Inhibitors/pharmacology , Protease Inhibitors/metabolism , Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Humans , Binding Sites , Catalytic Domain , Models, Molecular , Crystallography, X-Ray , Molecular Docking Simulation , COVID-19 Drug Treatment
17.
Fitoterapia ; 176: 106018, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38744385

ABSTRACT

An extensive phytochemical investigation on the rare medicinal plant Semiliquidambar cathayensis (family: Hamamelidaceae) led to the isolation of four new (1-4, named semiliquidacids A-D, respectively) and 25 related known pentacyclic triterpenoids. The new structures with absolute configurations were elucidated by spectroscopic methods, electronic circular dichroism (ECD) calculations, and single-crystal X-ray diffraction analysis. Compound 1 represents the first naturally occurring ursane-type triterpenoid featuring an uncommon C-25 formyl group. Compound 4 and oleanolic acid (13) exhibited remarkable inhibitory effects against the ATP-citrate lyase (ACL, an emerging drug target for hyperlipidemia and related metabolic disorders) with IC50 values of 6.5 and 11.9 µM, respectively. The molecular interaction and binding mode between the bioactive triterpenoids and ACL were elaborated by conducting a molecular docking study. Meanwhile, the chemotaxonomic significance of the isolated triterpenoids has been briefly discussed.


Subject(s)
ATP Citrate (pro-S)-Lyase , Molecular Docking Simulation , Pentacyclic Triterpenes , Plants, Medicinal , Molecular Structure , Plants, Medicinal/chemistry , Pentacyclic Triterpenes/pharmacology , Pentacyclic Triterpenes/isolation & purification , Pentacyclic Triterpenes/chemistry , ATP Citrate (pro-S)-Lyase/antagonists & inhibitors , Phytochemicals/pharmacology , Phytochemicals/isolation & purification , Phytochemicals/chemistry , Oleanolic Acid/isolation & purification , Oleanolic Acid/pharmacology , Oleanolic Acid/analogs & derivatives , Oleanolic Acid/chemistry , China , Enzyme Inhibitors/isolation & purification , Enzyme Inhibitors/pharmacology , Enzyme Inhibitors/chemistry
18.
Chem Sci ; 15(17): 6562-6571, 2024 May 01.
Article in English | MEDLINE | ID: mdl-38699271

ABSTRACT

Simultaneous imaging of nitric oxide (NO) and its proximal proteins should facilitate the deconvolution of NO-protein interactions. While immunostaining is a primary assay to localize proteins in non-genetically manipulated samples, NO imaging probes with immunostaining-compatible signals remain unexplored. Herein, probe NOP-1 was developed with an NO-triggered proximal protein labeling capacity and fluorogenic signals. The trick is to fuse the native chemical ligation of acyl benzotriazole with the protein-conjugation-induced fluorogenic response of Si-rhodamine fluorophore. NOP-1 predominantly existed in the non-fluorescent spirocyclic form. Yet, its acyl o-phenylenediamine moiety was readily activated by NO into acyl benzotriazole to conjugate proximal proteins, providing a fluorogenic response and translating the transient cellular NO signal into a permanent stain compatible with immunostaining. NOP-1 was utilized to investigate NO signaling in hypoglycemia-induced neurological injury, providing direct evidence of NO-induced apoptosis during hypoglycemia. Mechanistically, multiplex imaging revealed the overlap of cellular NOP-1 fluorescence with immunofluorescence for α-tubulin and NO2-Tyr. Importantly, α-tubulin was resolved from NOP-1 labeled proteins. These results suggest that NO played a role in hypoglycemia-induced apoptosis, at least in part, through nitrating α-tubulin. This study fills a crucial gap in current imaging probes, providing a valuable tool for unraveling the complexities of NO signaling in biological processes.

19.
ACS Infect Dis ; 10(6): 2303-2317, 2024 Jun 14.
Article in English | MEDLINE | ID: mdl-38725130

ABSTRACT

The design of siderophore-antibiotic conjugates is a promising strategy to overcome drug resistance in negative bacteria. However, accumulating studies have shown that only those antibiotics acting on the cell wall or cell membrane multiply their antibacterial effects when coupled with siderophores, while antibiotics acting on targets in the cytoplasm of bacteria do not show an obvious enhancement of their antibacterial effects when coupled with siderophores. To explore the causes of this phenomenon, we synthesized several conjugate probes using 3-hydroxypyridin-4(1H)-ones as siderophores and replacing the antibiotic cargo with 5-carboxyfluorescein (5-FAM) or malachite green (MG) cargo. By monitoring changes in the fluorescence intensity of FAM conjugate 20 in bacteria, the translocation of the conjugate across the outer membranes of Gram-negative pathogens was confirmed. Further, the use of the fluorogen activating protein(FAP)/MG system revealed that 3-hydroxypyridin-4(1H)-one-MG conjugate 26 was ultimately distributed mainly in the periplasm rather than being translocated into the cytosol of Escherichia coli and Pseudomonas aeruginosa PAO1. Additional mechanistic studies suggested that the uptake of the conjugate involved the siderophore-dependent iron transport pathway and the 3-hydroxypyridin-4(1H)-ones siderophore receptor-dependent mechanism. Meanwhile, we demonstrated that the conjugation of 3-hydroxypyridin-4(1H)-ones to the fluorescein 5-FAM can reduce the possibility of the conjugates crossing the membrane layers of mammalian Vero cells by passive diffusion, and the advantages of the mono-3-hydroxypyridin-4(1H)-ones as a delivery vehicle in the design of conjugates compared to the tri-3-hydroxypyridin-4(1H)-ones. Overall, this work reveals the localization rules of 3-hydroxypyridin-4(1H)-ones as siderophores to deliver the cargo into Gram-negative bacteria. It provides a theoretical basis for the subsequent design of siderophore-antibiotic conjugates, especially based on 3-hydroxypyridin-4(1H)-ones as siderophores.


Subject(s)
Anti-Bacterial Agents , Pseudomonas aeruginosa , Siderophores , Siderophores/chemistry , Siderophores/pharmacology , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , Pseudomonas aeruginosa/drug effects , Pseudomonas aeruginosa/metabolism , Gram-Negative Bacteria/drug effects , Fluorescent Dyes/chemistry , Escherichia coli/drug effects , Escherichia coli/metabolism , Pyridones/pharmacology , Pyridones/chemistry , Pyridines/chemistry , Pyridines/pharmacology , Animals , Fluorescein/chemistry , Biological Transport , Microbial Sensitivity Tests
20.
Anal Chem ; 96(22): 9034-9042, 2024 06 04.
Article in English | MEDLINE | ID: mdl-38773734

ABSTRACT

Allysine, a pivotal biomarker in fibrogenesis, has prompted the development of various radioactive imaging probes. However, fluorogenic probes targeting allysine remain largely unexplored. Herein, by leveraging the equilibrium between the nonfluorescent spirocyclic and the fluorescent zwitterionic forms of rhodamine-cyanine hybrid fluorophores, we systematically fine-tuned the environmental sensitivity of this equilibrium toward the development of fluorogenic probes for fibrosis. The trick lies in modulating the nucleophilicity of the ortho-carboxyl group, which is terminated with a hydrazide group for allysine conjugation. Probe B2 was developed with this strategy, which featured an N-sulfonyl amide group and exhibited superior fibrosis-to-control imaging contrast. Initially presenting as nonfluorescent spirocyclic aggregates in aqueous solutions, B2 displayed a notable fluorogenic response upon conjugation with protein allysine through its hydrazide group, inducing deaggregation and switching to the fluorescent zwitterionic form. Probe B2 outperformed the traditional Masson stain in imaging contrast, achieving an about 260-2600-fold ratio for fibrosis-to-control detection depending on fibrosis severity. Furthermore, it demonstrated efficacy in evaluating antifibrosis drugs. Our results emphasize the potential of this fluorogenic probe as an alternative to conventional fibrosis detection methods. It emerges as a valuable tool for antifibrosis drug evaluation.


Subject(s)
Fibrosis , Fluorescent Dyes , Fluorescent Dyes/chemistry , Fluorescent Dyes/chemical synthesis , Animals , Optical Imaging , Mice , Humans , Rhodamines/chemistry
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