SIRT3-dependent delactylation of cyclin E2 prevents hepatocellular carcinoma growth.

Lysine lactylation (Kla) is a recently discovered histone mark derived from metabolic lactate. The NAD+ -dependent deacetylase SIRT3, which can also catalyze removal of the lactyl moiety from lysine, is expressed at low levels in hepatocellular carcinoma (HCC) and has been suggested to be an HCC tumor suppressor. Here we report that SIRT3 can delactylate non-histone proteins and suppress HCC development. Using SILAC-based quantitative proteomics, we identify cyclin E2 (CCNE2) as one of the lactylated substrates of SIRT3 in HCC cells. Furthermore, our crystallographic study elucidates the mechanism of CCNE2 K348la delactylation by SIRT3. Our results further suggest that lactylated CCNE2 promotes HCC cell growth, while SIRT3 activation by Honokiol induces HCC cell apoptosis and prevents HCC outgrowth in vivo by regulating Kla levels of CCNE2. Together, our results establish a physiological function of SIRT3 as a delactylase that is important for suppressing HCC, and our structural data could be useful for the future design of activators.

Honokiol ameliorates angiotensin II-induced cardiac hypertrophy by promoting dissociation of the Nur77-LKB1 complex and activating the AMPK pathway.

Pathological cardiac hypertrophy is a key contributor to heart failure, and the molecular mechanisms underlying honokiol (HNK)-mediated cardioprotection against this condition remain worth further exploring. This study aims to investigate the effect of HNK on angiotensin II (Ang II)-induced myocardial hypertrophy and elucidate the underlying mechanisms. Sprague-Dawley rats were exposed to Ang II infusion, followed by HNK or vehicle treatment for 4 weeks. Our results showed that HNK treatment protected against Ang II-induced myocardial hypertrophy, fibrosis and dysfunction in vivo and inhibited Ang II-induced hypertrophy in neonatal rat ventricular myocytes in vitro. Mechanistically, HNK suppressed the Ang II-induced Nur77 expression at the transcriptional level and promoted ubiquitination-mediated degradation of Nur77, leading to dissociation of the Nur77-LKB1 complex. This facilitated the translocation of LKB1 into the cytoplasm and activated the LKB1-AMPK pathway. Our findings suggest that HNK attenuates pathological remodelling and cardiac dysfunction induced by Ang II by promoting dissociation of the Nur77-LKB1 complex and subsequent activation of AMPK signalling. This study uncovers a novel role of HNK on the LKB1-AMPK pathway to protect against cardiac hypertrophy.

Honokiol Is More Potent than Magnolol in Reducing Head and Neck Cancer Cell Growth.

The efficacy of treatment of head and neck squamous cell carcinoma (HNSCC) patients is still unsatisfactory, and there is an ongoing search for novel therapies. Locoregionally advanced HNSCC cases, which frequently require combined surgery and chemoradiotherapy, are especially difficult to treat. Natural compounds, like Magnolia-derived lignans-honokiol (HON) and magnolol (MAG)-can reduce cancer cell growth but retain a good safety profile and thus may show benefit as adjuvant therapeutics. The aim of this study was to evaluate the anti-cancer effects of HON and MAG in HNSCC cell lines and compare their effects between cisplatin-sensitive and cisplatin-tolerant cells. Cell viability was evaluated in FaDu and SCC-040 cells growing as monolayers and as spheroids. The effect of HON and MAG on the cell cycle, apoptosis, and gene expression was compared between wild-type FaDu cells and cisplatin persister FaDu cells. We observed that HON and MAG were more potent in reducing cell viability in cisplatin persister FaDu cells, although this effect was not directly followed by increased rates of apoptosis. Thus, HON's and MAG's capacity to affect cisplatin persister cells needs further studies. In general, we observed that HON exerted stronger cytotoxic effects than MAG in HNSCC cells, and the difference in their anti-cancer activity was especially pronounced in cells cultured in 3D.

Inhibition of Ca2+-permeable TRPV3 and inflammatory cytokine release by honokiol and magnolol in human epidermal keratinocytes.

Transient receptor potential vanilloid-3 (TRPV3) ion channels are prominently expressed in keratinocytes, playing a vital role in skin functions. Honokiol and magnolol (H&M) the primary bioactive constituents in Magnolia officinalis extract, demonstrate anti-inflammatory and skin-protective properties. Nevertheless, the underlying mechanism regarding their effect on Ca2+-permeable ion channels remain unclear. Our purpose in this study is to investigate the effect of H&M on TRPV3 and cytokine release in normal human epidermal keratinocytes (NHEKs), including its gain-of-function (GOF) mutants (G573S and G573C) associated with Olmstead syndrome. We performed whole-cell patch-clamp, fura-2 spectrofluorimetry to investigate channels activity, CCK-8 assay to analyze cell death and enzyme-linked immunosorbent assay to assess the cytokine release from NHEKs. H&M inhibited the TRPV3 current (ITRPV3) and cytosolic calcium increase in NHEKs, HEK293T cells overexpressing hTRPV3 and its GOF mutants. Moreover, the release of pro-inflammatory cytokines (interleukin-6 and -8) from keratinocytes stimulated by TRPV3 agonist was effectively suppressed by H&M. Our findings provide insights into the mechanism underlying the anti-inflammatory effects of H&M, highlighting their potential in treating skin diseases.

The PINK1/Parkin signaling pathway-mediated mitophagy: a forgotten protagonist in myocardial ischemia/reperfusion injury.

Myocardial ischemia causes extensive damage, further exacerbated by reperfusion, a phenomenon called myocardial ischemia/reperfusion injury (MIRI). Nowadays, the pathological mechanisms of MIRI have received extensive attention. Oxidative stress, multiple programmed cell deaths, inflammation and others are all essential pathological mechanisms contributing to MIRI. Mitochondria are the energy supply centers of cells. Numerous studies have found that abnormal mitochondrial function is an essential "culprit" of MIRI, and mitophagy mediated by the phosphatase and tensin homolog (PTEN)-induced kinase 1 (PINK1)/Parkin signaling pathway is an integral part of maintaining mitochondrial function. Therefore, exploring the association between the PINK1/Parkin signaling pathway-mediated mitophagy and MIRI is crucial. This review will mainly summarize the crucial role of the PINK1/Parkin signaling pathway-mediated mitophagy in MIR-induced several pathological mechanisms and various potential interventions that affect the PINK1/Parkin signaling pathway-mediated mitophagy, thus ameliorating MIRI.

Honokiol inhibits human osteosarcoma MG63 cell migration by upregulating FTO and Smad6 to promote autophagy.

BACKGROUND: Osteosarcoma (OS) is a common primary malignant tumor of bone, most commonly seen in children and adolescents, which has a low survival rate and is a serious threat to patients' lives. Honokiol (HKL) is the main active components of Magnolia officinalis, which have significant anti-tumor properties. The aim of this study was to observe the autophagic and migratory effects of HKL on MG63 cells and to investigate whether the mechanism of action was related to FTO and Smad6. METHODS: Firstly, we cultured MG63 cells in vitro and intervened with different concentrations of HKL to detect cell activity by CCK8, apoptosis by flow cytometry, cell migration ability by scratch assay, cell invasion ability by transwell assay and MMP2, P62, LC3 I/II, FTO and Smad6 protein expression by Western blot. RESULTS: HKL inhibited MG63 cells activity and that this effect was dose and time dependent. Although there was no significant effect on apoptosis and invasive ability, HKL could act through effects such as promoting cell autophagy and inhibiting migration. HKL increased the protein expression levels of FTO, Smad6, MMP2, LC3 I/II and P62, and this effect was reduced after silencing of Smad6. CONCLUSIONS: HKL induced autophagy and inhibited cell migration in MG63 cells by increasing the expression of FTP and Smad6. It can be seen that HKL may be a promising drug for the treatment of OS.

Semisynthesis and biological evaluation of novel honokiol thioethers against colon cancer cells HCT116 via inhibiting the transcription and expression of YAP protein.

Honokiol, derived from Magnolia officinalis (a traditional Chinese medicine), has been reported to have anticancer activity. Here, a series of novel honokiol thioethers bearing a 1,3,4-oxadiazole moiety were prepared and evaluated for their anticancer activities against three types of digestive system tumor cells. Biological evaluation showed that honokiol derivative 3k exhibited the best antiproliferative activity against HCT116 cells with an IC50 value of 6.1 µmol/L, superior to the reference drug 5-fluorouracil (IC50: 9.63 ± 0.27 µmol/L). The structure-activity relationships (SARs) indicated that the introduction of -(4-NO2)Ph, 3-pyridyl, -(2-F)Ph, -(4-F)Ph, -(3-F)Ph, -(4-Cl)Ph, and -(3-Cl)Ph groups was favorable for enhancing the anticancer activity of the title honokiol thioethers. Further study revealed that honokiol thioether 3k can well inhibit the proliferation of colon cancer cells HCT116, arresting the cells in G1 phase and inducing cell death. Moreover, a preliminary mechanism study indicated that 3k directly inhibits the transcription and expression of YAP protein without activating the Hippo signaling pathway. Thus, honokiol thioether 3k could be deeply developed for the development of honokiol-based anticancer candidates.

Toxicological effects of Honokiol on zebrafish and its underlying mechanism.

The compound Honokiol, derived from the bark of Magnolia officinalis, possesses the ability to induce apoptosis and inhibit cellular damage caused by reactive oxygen species. The objective of this study was to investigate the toxicological and histopathological effects of Honokiol on zebrafish (Danio rerio) through conducting a semistatic acute toxicity test involving immersion in an Honokiol-containing solution. The results showed that the toxic effects of Honokiol on zebrafish were primarily manifested in the liver and gills. When exposed to 0.6 mg/L of Honokiol, it could lead to liver hemorrhage as well as swelling and necrosis of gill tissues, and high concentrations of Honokiol could trigger inflammatory responses. Additionally, research found that Honokiol could induce apoptosis in liver and gill tissues through the P53 pathway and possessed the ability to enhance antioxidation. The present findings significantly contribute to a more profound understanding of the toxic impact of Honokiol and its underlying mechanism, thereby providing a valuable reference for the future safe utilization of Honokiol and related pharmaceutical advancements.

Mitochondrial impairment, decreased sirtuin activity and protein acetylation in dorsal root ganglia in Friedreich Ataxia models.

Friedreich ataxia (FA) is a rare, recessive neuro-cardiodegenerative disease caused by deficiency of the mitochondrial protein frataxin. Mitochondrial dysfunction, a reduction in the activity of iron-sulfur enzymes, iron accumulation, and increased oxidative stress have been described. Dorsal root ganglion (DRG) sensory neurons are among the cellular types most affected in the early stages of this disease. However, its effect on mitochondrial function remains to be elucidated. In the present study, we found that in primary cultures of DRG neurons as well as in DRGs from the FXNI151F mouse model, frataxin deficiency resulted in lower activity and levels of the electron transport complexes, mainly complexes I and II. In addition, altered mitochondrial morphology, indicative of degeneration was observed in DRGs from FXNI151F mice. Moreover, the NAD+/NADH ratio was reduced and sirtuin activity was impaired. We identified alpha tubulin as the major acetylated protein from DRG homogenates whose levels were increased in FXNI151F mice compared to WT mice. In the mitochondria, superoxide dismutase (SOD2), a SirT3 substrate, displayed increased acetylation in frataxin-deficient DRG neurons. Since SOD2 acetylation inactivates the enzyme, and higher levels of mitochondrial superoxide anion were detected, oxidative stress markers were analyzed. Elevated levels of hydroxynonenal bound to proteins and mitochondrial Fe2+ accumulation was detected when frataxin decreased. Honokiol, a SirT3 activator, restores mitochondrial respiration, decreases SOD2 acetylation and reduces mitochondrial superoxide levels. Altogether, these results provide data at the molecular level of the consequences of electron transport chain dysfunction, which starts negative feedback, contributing to neuron lethality. This is especially important in sensory neurons which have greater susceptibility to frataxin deficiency compared to other tissues.

Natural product honokiol exhibits antiviral effects against Micropterus salmoides rhabdovirus (MSRV) both in vitro and in vivo.

Micropterus salmoides rhabdovirus (MSRV) is a formidable pathogen, presenting a grave menace to juvenile largemouth bass. This viral infection frequently leads to epidemic outbreaks, resulting in substantial economic losses within the aquaculture industry. Unfortunately, at present, there are no commercially available vaccines or pharmaceutical treatments to combat this threat. In order to address the urgent need for therapeutic strategy to resist MSRV infection, the antiviral activity of natural product honokiol against MSRV was explored in this study. Firstly, cellular morphology was directly observed in an inverted microscope when treated with honokiol after MSRV infection. The results clarified that honokiol significantly lessened cytopathic effect (CPE) induced by MSRV and protected the integrity of GCO cells. Furthermore, the viral nucleic acid expression (G gene) was detected by reverse transcription real-time quantitative PCR (RT-qPCR) and the results indicated that honokiol significantly decreased the viral loads of MSRV in a concentration-dependent manner, and honokiol showed a high antiviral activity with IC50 of 2.92 µM. Besides, honokiol significantly decreased the viral titre and suppressed apoptosis caused by MSRV. Mechanistically, honokiol primarily inhibited the initial replication of MSRV and discharge of progeny virus to exert anti-MSRV activity. More importantly, in vivo experiments suggested that honokiol (40 mg/kg) expressed a fine antiviral activity against MSRV when administrated with intraperitoneal injection, which led to a notable 40% improvement in the survival rate among infected largemouth bass. In addition, it also resulted in significant reduction in the viral nucleic acid expression within liver, spleen and kidney at 2, 4 and 6 days following infection. What is more, 100 mg/kg honokiol with oral administration also showed certain antiviral efficacy in MSRV-infected largemouth bass via improving the survival rate by 10.0%, and decreasing significantly the viral nucleic acid expression in liver, spleen and kidney of largemouth bass on day 2. In summary, natural product honokiol is a good candidate to resist MSRV infection and has promising application prospects in aquaculture.

Honokiol regulates ovarian cancer cell malignant behavior through YAP/TAZ pathway modulation.

BACKGROUND: Ovarian cancer (OVCA) stands as one of the most fatal gynecological malignancies. Honokiol (HNK) has been substantiated by numerous studies for its anti-tumor activity against malignancies including OVCA. Consequently, this work was designed to elucidate the impact of HNK-mediated modulation of the YAP/TAZ pathway on the biological functions of OVCA cells. METHODS: OVCA cells were subjected to treatment with varying concentrations (0, 25, 50, 75, and 100 µM) of HNK, concomitant with the administration of YAP agonist (XMU). Assessment of cellular viability was executed employing the CCK-8 assay, while quantification of cellular proliferation transpired via colony formation assays. Apoptosis was ascertained using flow cytometry, and expression of apoptosis-related proteins (caspase-3, Bcl-2, Bax), EMT-related proteins (E-cadherin, N-cadherin), migration-associated proteins (MMP-2, MMP-9), and YAP/TAZ pathway-related proteins was evaluated by western blot. Transwell experiments were conducted to assess cellular migratory and invasive propensities. Xenograft tumor models were built to observe tumor growth (volume and weight), apoptosis was assessed by TUNEL staining, and Ki67 expression was evaluated through IHC. RESULTS: HNK exerted inhibitory effects on the viability and proliferative capacity of OVCA cells, elicited apoptotic responses, curtailed the migratory and invasive tendencies of cells, and downregulated the YAP/TAZ pathway. Stimulation with YAP agonist (XMU-MP-1) partially attenuated the impacts of HNK on OVCA cell biology. Experiments in vivo confirmed that HNK inhibited OVCA tumor growth. CONCLUSION: The outcomes of this investigation conclusively established that HNK orchestrated the modulation of the YAP/TAZ pathway, thereby exerting control over the malignant phenotypic manifestations of OVCA cells. The ascertained function of HNK in restraining cellular proliferation and tumor progression provided novel evidence of its anti-proliferative activity within OVCA cells.

Honokiol induces ferroptosis in ovarian cancer cells through the regulation of YAP by OTUB2.

BACKGROUND: Ovarian cancer (OVCA) is prevalent in female reproductive organs. Despite recent advances, clinical outcomes remain poor, warranting fresh treatment avenues. Honokiol has an inhibitory effect on proliferation, invasion, and survival of cancer cells in vitro and in vivo. Therefore, this study intended to explore specific molecular mechanism by which honokiol affected OVCA progression. METHODS: Bioinformatics analyzed the drug honokiol that bound to OTU deubiquitinase, ubiquitin aldehyde binding 2 (OTUB2). Cellular thermal shift assay (CETSA) verified the binding relationship between honokiol and OTUB2. Cell counting kit 8 (CCK-8) tested the IC50 value and cell viability of OVCA cells after honokiol treatment. Corresponding assay kits determined malonic dialdehyde (MDA) and Fe2+ levels in OVCA cells. Flow cytometry measured reactive oxygen species levels. Western blot detected OTUB2, SLC7A11, and transcriptional co-activators Yes-associated protein (YAP) expression, and quantitative polymerase chain reaction (qPCR) detected OTUB2 expression. Immunohistochemistry (IHC) detected the expression level of Ki67 protein in tumor tissues. RESULTS: Honokiol was capable of inducing ferroptosis in OVCA cells. CETSA confirmed that honokiol could bind to OTUB2. Further cell functional and molecular experiments revealed that honokiol induced ferroptosis in OVCA cells via repression of YAP signaling pathway through binding to OTUB2. In addition, in vivo experiments have confirmed that honokiol could inhibit the growth of OVCA. CONCLUSION: Honokiol induced ferroptosis in OVCA cells via repression of YAP signaling pathway through binding to OTUB2, implicating that OTUB2 may be an effective target for OVCA treatment, and our study results may provide new directions for development of more effective OVCA treatment strategies.

Delivery Strategies, Structural Modification, and Pharmacological Mechanisms of Honokiol: A Comprehensive Review.

Honokiol (HK) is a traditional Chinese herbal bioactive compound that originates mainly from the Magnolia species, traditionally used to treat anxiety and stroke, as well as alleviation of flu symptoms. This natural product and its derivatives displayed diverse biological activities, including anticancer, antioxidant, anti-inflammatory, neuroprotective, and antimicrobial activities. However, its poor bioavailability and pharmacological activity require primary consideration in the development of HK-based drugs. Recent innovative HK formulations based on the nanotechnology approach allowed for improvement in both bioavailability and therapeutic efficacy. Chemical derivation and drug combination are also effective strategies to ameliorate the drawbacks of HK. In recent years, studies on HK derivatives and compositions have made great progress in the treatment of cancer, inflammation, bacterial infection, cardiovascular, and cerebrovascular diseases, demonstrating better activity than HK. The objective of this review is an examination of the recent developments in the field of pharmacological activity of HK and its drug-related issues, and approaches to improve its physicochemical and biological properties, including solubility, stability, and bioavailability. Recent patents and the ongoing clinical trials in HK are also summarized.

Determination of Potential Lead Compound from Magnolia officinalis for Alzheimer's Disease through Pharmacokinetic Prediction, Molecular Docking, Dynamic Simulation, and Experimental Validation.

Amyloid ß protein (Aß) deposition has been implicated as the molecular driver of Alzheimer's disease (AD) progression. The modulation of the formation of abnormal aggregates and their post-translational modification is strongly suggested as the most effective approach to anti-AD. Beta-site APP-cleaving enzyme 1 (BACE1) acts upstream in amyloidogenic processing to generate Aß, which rapidly aggregates alone or in combination with acetylcholinesterase (AChE) to form fibrils. Accumulated Aß promotes BACE1 activation via glycogen synthase kinase-3ß (GSK-3ß) and is post-translationally modified by glutaminyl cyclase (QC), resulting in increased neurotoxicity. A novel multi-target inhibitor as a potential AD agent was identified using an in silico approach and experimental validation. Magnolia officinalis, which showed the best anti-AD activity in our preliminary study, was subjected to analysis, and 82 compounds were studied. Among 23 compounds with drug-likeness, blood-brain barrier penetration, and safety, honokiol emerged as a lead structure for the inhibition of BACE1, AChE, QC, and GSK-3ß in docking and molecular dynamics (MD) simulations. Furthermore, honokiol was found to be an excellent multi-target inhibitor of these enzymes with an IC50 of 6-90 µM, even when compared to other natural single-target inhibitors. Taken together, the present study is the first to demonstrate that honokiol acts as a multiple enzyme inhibitor with an excellent pharmacokinetic and safety profile which may provide inhibitory effects in broad-range areas including the overproduction, aggregation, and post-translational modification of Aß. It also provides insight into novel structural features for the design and discovery of multi-target inhibitors for anti-AD.

Honokiol alleviates monosodium urate-induced gouty pain by inhibiting voltage-gated proton channels in mice.

OBJECTIVE: To investigate whether honokiol (HNK) acted as an analgesic in connection with inhibiting the voltage-gated proton channel (Hv1). METHODS: The model of gouty arthritis was induced by injecting monosodium urate (MSU) crystals into the hind ankle joint of mice. HNK was given by intragastric administration. Ankle swelling degree and mechanical allodynia were evaluated using ankle joint circumference measurement and von Frey filaments, respectively. Hv1 current, tail current, and action potential in dorsal root ganglion (DRG) neurons were recorded with patch-clamp techniques. RESULTS: HNK (10, 20, 40 mg/kg) alleviated inflammatory response and mechanical allodynia in a dose-dependent manner. In normal DRG neurons, 50 µM Zn2+ or 2-GBI significantly inhibited the Hv1 current and the current density of Hv1 increased with increasing pH gradient. The amplitude of Hv1 current significantly increased on the 3rd after MSU treatment, and HNK dose-dependently reversed the upregulation of Hv1 current. Compared with MSU group, 40 mg/kg HNK shifted the activation curve to the direction of more positive voltage and increased reversal potential to the normal level. In addition, 40 mg/kg HNK reversed the down-regulation of tail current deactivation time constant (τtail) but did not alter the neuronal excitability of DRG neurons in gouty mice. CONCLUSION: HNK may be a potential analgesic by inhibiting Hv1 current.

Extraction and Biological Activity of Lignanoids from Magnolia officinalis Rehder & E.H.Wilson Residual Waste Biomass Using Deep Eutectic Solvents.

Lignanoids are an active ingredient exerting powerful antioxidant and anti-inflammatory effects in the treatment of many diseases. In order to improve the efficiency of the resource utilization of traditional Chinese medicine waste, Magnolia officinalis Rehder & E.H.Wilson residue (MOR) waste biomass was used as raw material in this study, and a series of deep eutectic solvents (ChUre, ChAce, ChPro, ChCit, ChOxa, ChMal, ChLac, ChLev, ChGly and ChEG) were selected to evaluate the extraction efficiency of lignanoids from MORs. The results showed that the best conditions for lignanoid extraction were a liquid-solid ratio of 40.50 mL/g, an HBD-HBA ratio of 2.06, a water percentage of 29.3%, an extract temperature of 337.65 K, and a time of 107 min. Under these conditions, the maximum lignanoid amount was 39.18 mg/g. In addition, the kinetics of the extraction process were investigated by mathematic modeling. In our antioxidant activity study, high antioxidant activity of the lignanoid extract was shown in scavenging four different types of free radicals (DPPH, ·OH, ABTS, and superoxide anions). At a concentration of 3 mg/mL, the total antioxidant capacity of the lignanoid extract was 1.795 U/mL, which was equal to 0.12 mg/mL of Vc solution. Furthermore, the antibacterial activity study found that the lignanoid extract exhibited good antibacterial effects against six tested pathogens. Among them, Staphylococcus aureus exerted the strongest antibacterial activity. Eventually, the correlation of the lignanoid extract with the biological activity and physicochemical properties of DESs is described using a heatmap, along with the evaluation of the in vitro hypoglycemic, in vitro hypolipidemic, immunomodulatory, and anti-inflammatory activity of the lignanoid extract. These findings can provide a theoretical foundation for the extraction of high-value components from waste biomass by deep eutectic solvents, as well as highlighting its specific significance in natural product development and utilization.

Co-Delivery of Gemcitabine and Honokiol by Lipid Bilayer-Coated Mesoporous Silica Nanoparticles Enhances Pancreatic Cancer Therapy via Targeting Depletion of Tumor Stroma.

Syndecan-1 (SDC1) modified lipid bilayer (LB)-coated mesoporous silica nanoparticles (MSN) to co-deliver gemcitabine (GEM) and honokiol (HNK) were prepared for the targeting treatment of pancreatic cancer. The encapsulation efficiencies of GEM and HNK in SDC1-LB-MSN-GEM/HNK were determined to be 60.3 ± 3.2% and 73.0 ± 1.1%. The targeting efficiency of SDC1-LB-MSN-GEM/HNK was investigated in BxPC-3 cells in vitro. The fluorescence intensity in the cells treated with SDC1-LB-MSN-Cou6 was 2-fold of LB-MSN-Cou6-treated cells, which was caused by SDC1/IGF1R-mediated endocytosis. As anticipated, its cytotoxicity was significantly increased. Furthermore, the mechanism was verified that SDC1-LB-MSN-HNK induced tumor cell apoptosis through the mitochondrial apoptosis pathway. Finally, the biodistribution, tumor growth inhibition, and preliminary safety studies were performed on BALB/c nude mice bearing BxPC-3 tumor models. The tumor growth inhibition index of SDC1-LB-MSN-GEM/HNK was 56.19%, which was 1.45-fold and 1.33-fold higher than that of the free GEM/HNK and LB-MSN-GEM/HNK treatment groups, respectively. As a result, SDC1-LB-MSN-GEM/HNK combined advantages of both GEM and HNK and simultaneously targeted and eliminated pancreatic cancerous and cancer-associated stromal cells. In summary, the present study demonstrated a new strategy of synergistic GEM and HNK to enhance the therapeutic effect of pancreatic cancer via the targeting depletion of tumor stroma.

Sirtuin 3 ameliorates inflammatory bowel disease via inhibiting intestinal inflammation and oxidative stress.

Sirtuin 3 involved in development of various diseases, but its role in inflammatory bowel disease is still unknown. We used inflammatory bowel disease biopsies, colitis animal model, and vitro cells RAW264.7 to study the role of Sirtuin 3 in the pathophysiology of inflammatory bowel disease. Sirtuin 3 negatively correlated with intestinal TNF-α. Sirt3 was less pronounced in pediatric and adult inflammatory bowel disease patients compared with corresponding control group. Sirtuin 3 activator Honokiol suppressed dextran sulfate sodium induced colonic manifestations, while Sirt3 inhibitor caused opposite results. Honokiol inhibited colonic oxidative stress by and reduced intestinal permeability. Honokiol repressed inflammatory response by reducing macrophage infiltration, pro-inflammatory cytokines TNF-α, IL-1ß, and IL-6 levels, and inhibiting activation of NF-κB p65 in the colitis mice. However, Sirt3 inhibitor amplified colonic oxidative stress and inflammatory response. In vitro study, Sirt3 inhibitor or siRNA Sirtuin 3 activated NF-κB p65 and enhanced TNF-α, IL-1ß, and IL-6 secretion from LPS stimulated RAW264.7, while Honokiol remarkably attenuated these pro-inflammatory cytokines secretion. Finally, knockdown of Sirt3 in Caco-2 cells enhanced TNF-α induced intestinal barrier integrity injury. Sirtuin 3 negatively regulates inflammatory bowel disease progression via reducing colonic inflammation and oxidative stress. Sirtuin 3 is a promising therapeutic target in clinical application for inflammatory bowel disease therapy.

SIRT3 Is a Critical Regulator of Mitochondrial Function of Fibroblasts in Pulmonary Hypertension.

Pulmonary hypertension (PH) is a heterogeneous and life-threatening cardiopulmonary disorder in which mitochondrial dysfunction is believed to drive pathogenesis, although the underlying mechanisms remain unclear. To determine if abnormal SIRT3 (sirtuin 3) activity is related to mitochondrial dysfunction in adventitial fibroblasts from patients with idiopathic pulmonary arterial hypertension (IPAH) and hypoxic PH calves (PH-Fibs) and whether SIRT3 could be a potential therapeutic target to improve mitochondrial function, SIRT3 concentrations in control fibroblasts, PH-Fibs, and lung tissues were determined using quantitative real-time PCR and western blot. SIRT3 deacetylase activity in cells and lung tissues was determined using western blot, immunohistochemistry staining, and immunoprecipitation. Glycolysis and mitochondrial function in fibroblasts were measured using respiratory analysis and fluorescence-lifetime imaging microscopy. The effects of restoring SIRT3 activity (by overexpression of SIRT3 with plasmid, activation SIRT3 with honokiol, and supplementation with the SIRT3 cofactor nicotinamide adenine dinucleotide [NAD+]) on mitochondrial protein acetylation, mitochondrial function, cell proliferation, and gene expression in PH-Fibs were also investigated. We found that SIRT3 concentrations were decreased in PH-Fibs and PH lung tissues, and its cofactor, NAD+, was also decreased in PH-Fibs. Increased acetylation in overall mitochondrial proteins and SIRT3-specific targets (MPC1 [mitochondrial pyruvate carrier 1] and MnSOD2 [mitochondrial superoxide dismutase]), as well as decreased MnSOD2 activity, was identified in PH-Fibs and PH lung tissues. Normalization of SIRT3 activity, by increasing its expression with plasmid or with honokiol and supplementation with its cofactor NAD+, reduced mitochondrial protein acetylation, improved mitochondrial function, inhibited proliferation, and induced apoptosis in PH-Fibs. Thus, our study demonstrated that restoration of SIRT3 activity in PH-Fibs can reduce mitochondrial protein acetylation and restore mitochondrial function and PH-Fib phenotype in PH.

Honokiol ameliorates cigarette smoke-induced damage of airway epithelial cells via the SIRT3/SOD2 signalling pathway.

Cigarette smoking can cause damage of airway epithelial cells and contribute to chronic obstructive pulmonary disease (COPD). Honokiol is originally isolated from Magnolia obovata with multiple biological activities. Here, we investigated the protective effects of honokiol on cigarette smoke extract (CSE)-induced injury of BEAS-2B cells. BEAS-2B cells were treated with 300 mg/L CSE to construct an in vitro cell injury model, and cells were further treated with 2, 5 and 10 µM honokiol, then cell viability and LDH leakage were analysed by CCK-8 and LDH assay kits, respectively. Apoptosis was detected by flow cytometry analysis. ELISA was used to measure the levels of tumour necrosis factor (TNF)-ɑ, IL-1ß, IL-6, IL-8 and MCP-1. The results showed that honokiol (0.5-20 µM) showed non-toxic effects on BEAS-2B cells. Treatment with honokiol (2, 5 and 10 µM) reduced CSE (300 mg/L)-induced decrease in cell viability and apoptosis in BEAS-2B cells. Honokiol also decreased CSE-induced inflammation through inhibiting expression and secretion of inflammatory cytokines, such as TNF-ɑ, IL-1ß, IL-6, IL-8 and MCP-1. Moreover, honokiol repressed CSE-induced reactive oxygen species (ROS) production, decrease of ATP content and mitochondrial biogenesis, as well as mitochondrial membrane potential. Mechanistically, honokiol promoted the expression of SIRT3 and its downstream target genes, which are critical regulators of mitochondrial function and oxidative stress. Silencing of SIRT3 reversed the protective effects of honokiol on CSE-induced damage and mitochondrial dysfunction in BEAS-2B cells. These results indicated that honokiol attenuated CSE-induced damage of airway epithelial cells through regulating SIRT3/SOD2 signalling pathway.