Affinity-based protein profiling-driven discovery of myricanol as a Nampt activator.

Herein, we synthesized an affinity-based probe of myricanol (pMY) with a photo-affinity cross-linker to initiate a bioconjugation reaction, which was applied for target identification in live C2C12 myotubes. Pull-down of biotinylated pMY coupled with mass spectroscopy and Western blotting revealed that pMY can bind with nicotinamide phosphoribosyltransferase (Nampt), a rate-limiting enzyme in the nicotinamide adenine dinucleotide salvage pathway. Cellular thermal shift assay, drug affinity responsive target stability assay and recombinant protein labeling further validated the direct interaction between myricanol and Nampt. Myricanol did not affect the protein expression of Nampt, but enhanced its activity. Knock-down of Nampt totally abolished the promoting effect of myricanol on insulin-stimulated glucose uptake in C2C12 myotubes. Taken together, myricanol sensitizes insulin action in myotubes through binding with and activating Nampt.

14-Deoxygarcinol improves insulin sensitivity in high-fat diet-induced obese mice via mitigating NF-κB/Sirtuin 2-NLRP3-mediated adipose tissue remodeling.

Interleukin (IL)-1ß is a culprit of adipose tissue inflammation, which in turn causes systematic inflammation and insulin resistance in obese individuals. IL-1ß is mainly produced in monocytes and macrophages and marginally in adipocytes, through cleavage of the inactive pro-IL-1ß precursor by caspase-1, which is activated via the NLRP3 inflammasome complex. The nuclear factor-κB (NF-κB) transcription factor is the master regulator of inflammatory responses. Brindle berry (Garcinia cambogia) has been widely used as health products for treating obesity and related metabolic disorders, but its active principles remain unclear. We previously found a series of polyisoprenylated benzophenones from brindle berry with anti-inflammatory activities. In this study we investigated whether 14-deoxygarcinol (DOG), a major polyisoprenylated benzophenone from brindle berry, alleviated adipose tissue inflammation and insulin sensitivity in high-fat diet fed mice. The mice were administered DOG (2.5, 5 mg · kg-1 · d-1, i.p.) for 4 weeks. We showed that DOG injection dose-dependently improved insulin resistance and hyperlipidemia, but not adiposity in high-fat diet-fed mice. We found that DOG injection significantly alleviated adipose tissue inflammation via preventing macrophage infiltration and pro-inflammatory polarization of macrophages, and adipose tissue fibrosis via reducing the abnormal deposition of extracellular matrix. In LPS plus nigericin-stimulated THP-1 macrophages, DOG (1.25, 2.5, 5 µM) dose-dependently suppressed the activation of NLRP3 inflammasome and NF-κB signaling pathway. We demonstrated that DOG bound to and activated the deacetylase Sirtuin 2, which in turn deacetylated and inactivated NLRP3 inflammasome to reduce IL-1ß secretion. Moreover, DOG (1.25, 2.5, 5 µM) dose-dependently mitigated inflammatory responses in macrophage conditioned media-treated adipocytes and suppressed macrophage migration toward adipocytes. Taken together, DOG might be a drug candidate to treat metabolic disorders through modulation of adipose tissue remodeling.

The First Phytochemical Investigation of Artemisia divaricate: Sesquiterpenes and Their Anti-Inflammatory Activity.

Artemisia divaricate belongs to the Artemisia genus of the family of Compositae, a sort of perennial herb endemic in most regions of China. For the first time, a phytochemical investigation was carried out on the whole plant of Artemisia divaricate, resulting in the identification of 39 sesquiterpenes, with 9 of them being new (1-9). The structures of the new compounds were fully established using extensive analysis of MS and 1D and 2D NMR spectroscopic data and density functional theory (DFT) NMR calculations. Their structures involve germacrane, eudesmane, and bisabolane types. All the new isolates were evaluated for their anti-inflammatory activities in lipopolysaccharide (LPS)-stimulated murine macrophages of RAW 264.7 cells. Compounds 2 and 8 showed a significant inhibition effect on NO production, with IC50 values of 5.35 ± 0.75 and 7.68 ± 0.54 µM, respectively.

Ainsliadimer C, a disesquiterpenoid isolated from Ainsliaea macrocephala, ameliorates inflammatory responses in adipose tissue via Sirtuin 1-NLRP3 inflammasome axis.

Interleukin-1ß (IL-1ß), a key pro-inflammatory cytokine, is majorly produced by macrophages through NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome, which has been identified as the culprit to deteriorate the inflammatory crosstalk between macrophages and adipocytes. Ainsliadimer C (AC) is a disesquiterpenoid isolated from Ainsliaea macrocephala. In the current study, we investigated the effects of AC on adipose tissue inflammation in co-culture of macrophages and adipocytes in vitro as well as in LPS-treated mice in vivo. We showed that AC (20-80 µM) dose-dependently inhibited the secretion of IL-1ß from LPS plus ATP-stimulated THP-1 macrophages by inhibiting the activation of NLRP3 inflammasome. Furthermore, we found that AC treatment activated NAD+-dependent deacetylase Sirtuin 1 (SIRT1), resulting in reduced acetylation level of NLRP3. Molecular modeling analysis revealed that binding of AC to sirtuin-activating compound-binding domain increased the affinity of the substrate to the catalytic domain of SIRT1. Moreover, AC (80 µM) significantly attenuated macrophage-conditioned medium-induced inflammatory responses in 3T3-L1 adipocytes. In LPS-induced acute inflammatory mice, administration of AC (20, 60 mg·kg-1·d-1, ip) for 5 days significantly suppressed the pro-inflammatory cytokine levels in serum and epididymal white adipose tissue (eWAT), attenuated macrophage infiltration into eWAT, and mitigated adipose tissue inflammation. The beneficial effects of AC were blocked by co-administration of a selective SIRT1 inhibitor EX-527 (10 mg·kg-1·d-1). Taken together, AC suppresses NLRP3-mediated IL-1ß secretion through activating SIRT1, leading to attenuated inflammation in macrophages and adipose tissue, which might be a candidate to treat obesity-associated metabolic diseases.

Macrocephatriolides A and B: Two Guaianolide Trimers from Ainsliaea macrocephala as PTP1B Inhibitors and Insulin Sensitizers.

Macrocephatriolides A and B (1 and 2), two novel guaiane-type sesquiterpene lactone trimers possessing unique linkage patterns, were identified from the whole plant of Ainsliaea macrocephala. The trimeric architecture of 1 features a cyclohexene linkage and a methylene bridge, which were presumably constructed from three constitutive monomers via a Diels-Alder cycloaddition and a Michael addition, respectively. The three monomers of 2 were tethered by a 1,2-ethanediyl and a methylene linkage at the same time. Their complex structures were established by extensive analysis of spectroscopic data inclusive of band-selective CT-HSQC and CT-HMBC and time-dependent density functional theory (TDDFT) ECD calculations. Compound 2 showed potent inhibition against protein tyrosine phosphatase 1B (PTP1B) with an IC50 value of 26.26 ± 0.88 µM but not compound 1. In the kinetic study, compound 2 was disclosed as a competitive inhibitor of PTP1B with a Ki value of 16.34 ± 4.72 µM. In insulin-stimulated C2C12 myotubes, compound 2 dose-dependently enhanced glucose uptake by activating the insulin signaling pathway. Compound 2 might represent a new scaffold of insulin sensitizers.

Caesalpinaxin, a cassane-type diterpenoid with a 21-carbon core skeleton from the seeds of Caesalpinia minax possessing pro-angiogenetic property.

A novel cassane-type diterpenoid, caesalpinaxin (1), was isolated from the seeds of Caesalpinia minax Hance. The structure of caesalpinaxin was established by means of spectroscopic techniques (NMR, HR-ESIMS, UV and IR). The absolute configuration of caesalpinaxin was determined by quantum chemical calculations of its theoretical electronic circular dichroism (ECD) spectrum. Caesalpinaxin is the first cassane-type diterpenoid with 21 carbons core skeleton, containing an unusual δ-lactone ring. A plausible biosynthetic pathway was proposed for compound 1. Furthermore, caesalpinaxin was tested for the pro-angiogenetic activity on human umbilical vein endothelial cells(HUVECs). The results indicated that this compound significantly stimulated migration and tuber formation through enhancing the level of vascular endothelial growth factor (VEGF). Thus, caesalpinaxin might be applied in accelerating wound healing.

Anti-Hyperglycemic Effects of Refined Fractions from Cyclocarya paliurus Leaves on Streptozotocin-Induced Diabetic Mice.

To identify the chemical components responsible for the anti-hyperglycemic effect of Cyclocarya paliurus (Batal.) Iljinsk (Juglandaceae) leaves, an ethanol extract (CPE) and a water extract (CPW) of C. paliurus leaves, as well as their total flavonoids (CPF), triterpenoids (CPT) and crude polysaccharides (CPP), were prepared and assessed on streptozotocin (STZ)-induced diabetic mice. After being orally administrated once a day for 24 days, CPF (300 mg/kg), CPP (180 mg/kg), or CPF+CPP (300 mg/kg CPF + 180 mg/kg CPP) treatment reversed STZ-induced body weight and muscle mass losses. The glucose tolerance tests and insulin tolerance tests suggested that CPF, CPP, and CPF+CPP showed anti-hyperglycemic effect in STZ-induced diabetic mice. Furthermore, CPF enhances glucose-stimulated insulin secretion in MIN6 cells and insulin-stimulated glucose uptake in C2C12 myotubes. CPF and CPP suppressed inflammatory cytokine levels in STZ-induced diabetic mice. Additionally, CPF and CPP improved STZ-induced diabetic nephropathy assessed by H&E staining, blood urea nitrogen content, and urine creatinine level. The molecular networking and Emperor analysis results indicated that CPF showed potential anti-hyperglycemic effects, and HPLC-MS/MS analysis indicated that CPF contains 3 phenolic acids and 9 flavonoids. In contrast, CPT (650 mg/kg) and CPC (300 mg/kg CPF + 180 mg/kg CPP + 650 mg/kg CPT) did not show anti-hyperglycemic effect. Taken together, polysaccharides and flavonoids are responsible for the anti-hyperglycemic effect of C. paliurus leaves, and the clinical application of C. paliurus need to be refined.

Nagilactone D ameliorates experimental pulmonary fibrosis in vitro and in vivo via modulating TGF-ß/Smad signaling pathway.

Pulmonary fibrosis is a prototypic chronic progressive lung disease with high morbidity and mortality worldwide. Novel effective therapeutic agents are urgently needed owing to the limited treatment options in clinic. Herein, nagilactone D (NLD), a natural dinorditerpenoid obtained from Podocarpus nagi, was found to suppress transforming growth factor-ß1 (TGF-ß1)-mediated fibrotic process in vitro and bleomycin (BLM)-induced pulmonary fibrosis in vivo. NLD attenuated TGF-ß1-induced expression of fibrotic markers including type I and III collagen, fibronectin, α-SMA, and CTGF in human pulmonary fibroblasts (WI-38 VA-13 and HLF-1 cells). Mechanism study indicated that NLD suppressed TGF-ß1-induced up-regulation of TßR I, and Smad2 phosphorylation, nuclear translocation, and transcriptional activation. Moreover, NLD ameliorated BLM-induced histopathological abnormalities in the lungs of experimental fibrotic mice, suppressed synthesis of relative fibrotic markers and fibroblast-to-myofibroblast transition, as well as BLM-induced up-regulation of TßR I expression and Smad signaling in mouse lungs. These data collectively support NLD to be a potential therapeutic agent for pulmonary fibrosis.

Xanthones, A Promising Anti-Inflammatory Scaffold: Structure, Activity, and Drug Likeness Analysis.

Inflammation is the body's self-protective response to multiple stimulus, from external harmful substances to internal danger signals released after trauma or cell dysfunction. Many diseases are considered to be related to inflammation, such as cancer, metabolic disorders, aging, and neurodegenerative diseases. Current therapeutic approaches include mainly non-steroidal anti-inflammatory drugs and glucocorticoids, which are generally of limited effectiveness and severe side-effects. Thus, it is urgent to develop novel effective anti-inflammatory therapeutic agents. Xanthones, a unique scaffold with a 9H-Xanthen-9-one core structure, widely exist in natural sources. Till now, over 250 xanthones were isolated and identified in plants from the families Gentianaceae and Hypericaceae. Many xanthones have been disclosed with anti-inflammatory properties on different models, either in vitro or in vivo. Herein, we provide a comprehensive and up-to-date review of xanthones with anti-inflammatory properties, and analyzed their drug likeness, which might be potential therapeutic agents to fight against inflammation-related diseases.

Pimarane Diterpenoids from the Seeds of Caesalpinia minax as PTP1B Inhibitors and Insulin Sensitizers.

Protein-tyrosine phosphatase 1B (PTP1B) has been considered as a promising target for treating insulin resistance. In searching for naturally occurring PTB1B antagonists, two new pimarane diterpenoids, named 2α-hydroxy-7-oxo-pimara-8(9),15-diene (1) and 19-hydroxy-2α-acetoxy-7-oxo-pimara-8(9),15-diene (2), were isolated from the seeds of Caesalpinia minax. Their structures were determined by extensive analysis of NMR and HR-ESIMS data, and their absolute configurations were determined by electronic circular dichroism (ECD) spectra. Compound 1 was disclosed as a competitive inhibitor of PTP1B with an IC50 (the half-maximal inhibitory concentration) value of 19.44 ± 2.39 µM and a Ki (inhibition constant) value of 13.69 ± 2.72 µM. Moreover, compound 1 dose-dependently promoted insulin-stimulated glucose uptake in C2C12 myotubes through activating insulin signaling pathway. Compound 1 might be further developed as an insulin sensitizer.

Norditerpenoids and Dinorditerpenoids from the Seeds of Podocarpus nagi as Cytotoxic Agents and Autophagy Inducers.

Nine new norditerpenoids and dinorditerpenoids, 2-oxonagilactone A (1), 7ß-hydroxynagilactone D (2), nagilactones K and L (3 and 4), 3ß-hydroxynagilactone L (5), 2ß-hydroxynagilactone L (6), 3-epi-15-hydroxynagilactone D (7), 1α-chloro-2ß,3ß,15-trihydroxynagilactone L (8), and 15-hydroxynagilactone L (9), were isolated from the seeds of Podocarpus nagi, along with eight known analogues. The structures of the new compounds were established based on detailed NMR and HRESIMS analysis, as well as from their ECD spectra. The absolute configuration of the known compound 1-deoxy-2α-hydroxynagilactone A (16) was confirmed by single-crystal X-ray diffraction. All of the isolates were tested for their cytotoxic activities against cancer cells. The results indicated that compounds 4 and 6, as well as several known compounds, displayed cytotoxicity against A2780 and HEY cancer cells. Among the new compounds, 2ß-hydroxynagilactone L (6) showed IC50 values of less than 2.5 µM against the two cell lines used. Furthermore, compound 6 induced autophagic flux in A2780 cells, as evidenced by an enhanced expression level of the autophagy marker phosphatidylethanolamine-modified microtubule-associated protein light-chain 3 (LC3-II) and increased mRFP-GFP-LC3 puncta. Also, compound 6 activated the c-Jun N-terminal kinase (JNK) pathway, while pretreatment with the JNK inhibitor SP600125 decreased compound 6-induced autophagy.

Naturally Occurring Diterpenoid Dimers: Source, Biosynthesis, Chemistry and Bioactivities.

Diterpenoid dimers are rare in nature and mainly found in higher plants including the families Acanthaceae, Annonaceae, Asteraceae, Calceolariaceae, Chrysobalanaceae, Cupressaceae, Euphorbiaceae, Fabaceae, Lamiaceae, Liliaceae, Meliaceae, Rhizophoraceae, Taxaceae, Velloziaceae, and Zingiberaceae. In addition, a few diterpenoid dimers have been also reported from fungi (Psathyrellaceae), liverworts (Scapaniaceae), and a gorgonian (Gorgoniidae). They feature a wide variety of structures due to different core skeletons, linkage patterns, substituents, and configurations. Accordingly, diterpenoid dimers exhibit a broad range of bioactivities, including cytotoxic, anti-inflammatory, antimicrobial, antimalarial, and antifouling properties, which have attracted more and more research interests in the past decades. This review with 176 metabolites from 109 references provides a comprehensive and up-to-date overview of the source, biosynthesis, structure, synthesis, and bioactivities of diterpenoid dimers.

Germacrane-type sesquiterpenes from Pilea cavaleriei Levl. subsp. cavaleriei.

The first systematic investigation of germacrane-type sesquiterpenes from Pilea cavaleriei Levl. subsp. cavaleriei was conducted. Eleven undescribed germacrane analogues named cavalinols A-K were identified. Their planar structures were determined by extensive analysis of 1D and 2D NMR spectroscopic data, and the absolute configurations were further determined by X-ray single crystal diffraction, Mosher method, and time dependent density functional theory (TDDFT) electron circular dichroism (ECD) calculation, with the aid from DFT NMR calculation and NOESY experiment. Except for the common 10-memebered ring, ten new compounds contained a p-coumaroyl sidechain connected to C-8 of the nucleus skeleton. All the isolated compounds were screened for anti-inflammatory activity in LPS stimulated RAW 264.7 cells, and compounds 5 and 6 showed moderate activity.

Sesquiterpene lactones from Artemisia verlotorum and their anti-inflammatory activities.

Seven new sesquiterpenoids (1-7) and 19 known analogues were isolated from the whole plant of Artemisia verlotorum. Their structures were determined by extensive analysis of 1D and 2D NMR and HRESIMS data, electronic circular dichroism (ECD) spectra, density functional theory (DFT) NMR calculations, and time dependent density functional theory (TDDFT) ECD calculations. The absolute configurations of 1, 3, 5 and 7 were confirmed by single crystal X-ray diffraction experiments. Compounds 1 and 2 possess a rarely reported 5/8-bicyclic skeleton, while both compounds 3 and 4 were uncommon iphionane-type sesquiterpenoids. Eudesmane sesquiterpenoids (5-17) reported in this study are all 7,8-cis-lactones, of which, compound 7 represents the first eudesmane sesquiterpene with an oxygen bridge connecting C-5 and C-11. All the compounds were tested in vitro for their anti-inflammatory activities in LPS-stimulated RAW 264.7 murine macrophages. Compound 18 showed a potent inhibitory effect on NO production, with IC50 values of 3.08 ± 0.61 µM.

The first phytochemical investigation of Artemisia nujianensis: Eight new guaianolides and their anti-inflammatory activity.

The first phytochemical investigation of Artemisia nujianensis resulted in the isolation of eight new guaianolides (1-8) and six known analogs. Their structures were determined by extensive analysis of 1D and 2D NMR data, HRESIMS data, DFT NMR calculations, and X-ray diffraction studies. Some compounds were evaluated for their anti-inflammatory activities in LPS-stimulated RAW 264.7 cells. Compounds 5, 7 and 9 showed moderate inhibitory effects on LPS-induced NO production in RAW 264.7 cells, with IC50 values of 12.50 ± 0.21, 9.53 ± 0.14 and 6.85 ± 0.11 µM, respectively.

Bioactivity-based molecular networking-guided identification of guttiferone J from Garcinia cambogia as an anti-obesity candidate.

BACKGROUND AND PURPOSE: Pharmacological intervention to induce browning of white adipose tissue provides a promising anti-obesity therapy. The fruits of Garcinia cambogia (Clusiaceae) have been widely applied to manage body weight; however, the chemical principles remain unclear. The current study aims to discover browning inducers from the fruits of G. cambogia and investigate the underlying mechanisms. EXPERIMENTAL APPROACH: The bioactivity-based molecular networking and Oil Red O staining on 3T3-L1 and C3H10T1/2 adipocytes were applied for guided isolation. High-fat diet-induced obese mice were recruited to evaluate the anti-obesity activity. KEY RESULTS: The bioactivity-based molecular networking-guided isolation yielded several polycyclic polyprenylated acylphloroglucinols from the fruits of G. cambogia with lipid-lowering effect in adipocytes, including guttiferone J (GOJ), garcinol and 14-deoxygarcinol. As the most potent one, GOJ (10 µM) reduced lipid accumulation by 70% and 76% in 3T3-L1 and C3H10T1/2 adipocytes, respectively. Furthermore, GOJ (2.5-10 µM) increased the expression of the deacetylase sirtuin 3 (SIRT3) and activated it, which, in turn, reduced the acetylation level of PPARγ coactivator-1α to boost mitochondrial biogenesis and promoted uncoupling protein 1 expression to enhance thermogenesis, resulting in browning of adipocytes. In high-fat diet-induced-obese mice, GOJ (10 and 20 mg·kg-1 ·day-1 for 12 weeks) protected against adiposity, hyperlipidaemia, insulin resistance and liver lipotoxicity, through boosting SIRT3-mediated browning of inguinal adipose tissue. CONCLUSION AND IMPLICATIONS: GOJ represents a new scaffold of thermogenic inducer, which is responsible for the anti-obesity property of G. cambogia and can be further developed as a candidate for treating obesity and its related disorders.

Anti-proliferative cassane-type diterpenoids from the seeds of Caesalpinia minax.

The seeds of Caesalpinia minax Hance have shown anti-tumor potential, while the chemical principle is still unknown. In a search for anti-tumor compounds, six new cassane-type diterpenoids, 12-demethylcaesalpin G (1), caesalpinolide H (2), 12-demethylcaesalpin H (3), caesalpinolide J (4), 12-O-ethyl neocaesalpin B (5), and 3-deacetyldecapetpene B (6), were isolated from the seeds of C. minax Hance, along with fifteen known analogues. The structures of the new compounds were established by means of spectroscopic techniques (NMR, HRESIMS and IR). The absolute configurations of the new compounds were determined by their ECD spectra. All of the new compounds were tested for their anti-proliferative activity against human lung cancer A549 cells, breast cancer MCF-7 cells, and ovarian cancer HEY cells. The results indicated that only compound 6 displayed moderate cytotoxicity against three cancer cell lines. Thus, the opening of furan ring in cassane-type diterpenoids might enhance the cytotoxic activity.

Polyisoprenylated benzophenone derivatives from Garcinia cambogia and their anti-inflammatory activities.

Ten new polyisoprenylated benzophenone derivatives, 4,8-epi-uralione F (1), 4,8-epi-uralione G (2), uralione S (3), coccinone J (4), 6-epi-coccinone C (5), coccinone I (6), 36-hydroxy-guttiferone J (7), multiflorone I (8), garciniagifolone F (9) and 36-hydroxy-garciniagifolone F (10), were isolated from the fruits of Garcinia cambogia, along with seven known analogues. The structures of the new compounds were established based on the detailed analysis of 1D and 2D nuclear magnetic resonance (NMR) spectra and high resolution electrospray ionization mass spectrometra (HRESIMS), and their absolute configurations were determined from the electronic circular dichroism (ECD) spectra. All the isolates were tested for their inhibitory effects against nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. The results indicated that compound 1 displayed a potent NO inhibitory effect with an IC50 value of 41.60 ± 0.17 µM. Furthermore, compound 1 suppressed inducible NO synthase (iNOS) expression in a dose-dependent manner through inhibiting the activation of nuclear factor-κB (NF-κB).

The drug likeness analysis of anti-inflammatory clerodane diterpenoids.

Inflammation is an active defense response of the body against external stimuli. Long term low-grade inflammation has been considered as a deteriorated factor for aging, cancer, neurodegeneration and metabolic disorders. The clinically used glucocorticoids and non-steroidal anti-inflammatory drugs are not suitable for chronic inflammation. Therefore, it's urgent to discover and develop new effective and safe drugs to attenuate inflammation. Clerodane diterpenoids, a class of bicyclic diterpenoids, are widely distributed in plants of the Labiatae, Euphorbiaceae and Verbenaceae families, as well as fungi, bacteria, and marine sponges. Dozens of anti-inflammatory clerodane diterpenoids have been identified on different assays, both in vitro and in vivo. In the current review, the up-to-date research progresses of anti-inflammatory clerodane diterpenoids were summarized, and their druglikeness was analyzed, which provided the possibility for further development of anti-inflammatory drugs.

Nagilactone E increases PD-L1 expression through activation of c-Jun in lung cancer cells.

Nagilactone E (NLE), a natural product with anticancer activities, is isolated from Podocarpus nagi. In this study, we reported that NLE increased programmed death ligand 1 (PD-L1) expressions at both protein and mRNA levels in human lung cancer cells, and enhanced its localization on the cell membrane. Mechanistically, NLE increased the phosphorylation and expression of c-Jun, and promoted the localization of c-Jun in the nucleus, while silencing of c-Jun by small interfering RNA (siRNA) reduced NLE-induced PD-L1. Further study showed that NLE activated the c-Jun N-terminal kinases (JNK), the upstream of c-Jun, and its inhibitor SP600125 reversed the NLE-increased PD-L1. Moreover, NLE-induced PD-L1 increased the binding intensity of PD-1 on the cell surface. In summary, NLE upregulates the expression of PD-L1 in lung cancer cells through the activation of JNK-c-Jun axis, which has the potential to combine with the PD-1/PD-L1 antibody therapies in lung cancer.