Sclareol attenuates liver fibrosis through SENP1-mediated VEGFR2 SUMOylation and inhibition of downstream STAT3 signaling

SENP1-mediated deSUMOylation of YBX1 promotes colorectal cancer development through the SENP1-YBX1-AKT signaling axis

Aberrant SUMOylation is associated with the progression of colorectal cancer (CRC). The SUMO-specific protease 1 (SENP1)-induced deSUMOylation of different target substrates plays specific roles in CRC. In this study, we dissected the SENP1-interacting protein complex by employing protein co-immunoprecipitation enrichment in combination with His6-SUMO1T95K-tagging mass spectrometry (MS) identification, and identified YBX1 as a novel substrate of SENP1. Further studies revealed that SENP1 interacted with YBX1 and consequently catalyzed YBX1 deSUMOylation at K26 residue preferentially. SENP1-mediated deSUMOylation enhanced the pro-tumor activity of YBX1 protein by maintaining the interaction of YBX1 with DDX5, thereby activating AKT phosphorylation signaling and promoting CRC tumor growth. Indeed, SENP1 knockdown elevated YBX1 SUMOylation and disrupted the interaction between YBX1 with DDX5, which significantly inhibited CRC cell proliferation and migration. And overexpression of K26 mutant YBX1 (YBX1-K26R) protein rescued the anti-tumor effect of SENP1 depletion compared with the wild-type YBX1 (YBX1-WT). Moreover, the expression levels of SENP1 and YBX1 were both increased in CRC specimens and associated with poor outcomes in CRC patients. In general, our studies have revealed SENP1-mediated YBX1 protein deSUMOylation promotes CRC progression through the activation of AKT phosphorylation signaling, suggesting that targeting the SENP1-YBX1-AKT signaling axis is a promising therapeutic strategy for CRC.

Comprehensive multi-omics and pharmacokinetics reveal sclareol's role in inhibiting ocular neovascularization

BACKGROUND

Ocular neovascularization, a hallmark of several vision-threatening diseases, including retinopathy of prematurity (ROP) and wet age-related macular degeneration (wet AMD), is commonly treated with intravitreal injections of anti-VEGF agents. However, these treatments are limited by invasiveness and drug resistance, highlighting the need for alternative therapies. Sclareol (SCL), a labdane diterpenoid derived from Salvia sclarea, exhibits various biological activities, but its potential role in angiogenesis and pharmacokinetics after oral administration remain unexplored.

METHODS

Hypoxia-induced endothelial cells (ECs) were used as an in vitro model, while mouse oxygen-induced retinopathy (OIR) and laser-induced choroidal neovascularization (CNV) were used as in vivo models. The pharmacokinetics of SCL in plasma, retina, and choroid were analyzed after oral administration in mice. Furthermore, the underlying mechanisms were elucidated through an integrative approach combining transcriptomics, metabolomics, network pharmacology, molecular docking, and molecular dynamics simulation.

RESULTS

SCL inhibited hypoxia-induced EC proliferation, permeability, migration, tube formation, sprouting, glycolysis, mitochondrial respiration, and oxidative stress by modulating the PI3K-AKT-FOXO1 pathway. Additionally, Oral administration of SCL significantly inhibited OIR and CNV progression in mice, demonstrating enhanced therapeutic efficacy when combined with intravitreal aflibercept (Eylea) injection.

CONCLUSION

SCL is a promising orally administered natural compound for ocular neovascularization, offering a potential alternative or adjunctive therapy to existing anti-VEGF treatments.

New insights into SUMOylation and NEDDylation in fibrosis

Fibrosis is the outcome of any abnormal tissue repair process that results in normal tissue replacement with scar tissue, leading to persistent tissue damage and cellular injury. During the process of fibrosis, many cytokines and chemokines are involved, and their activities are controlled by post-translational modifications, especially SUMOylation and NEDDylation. Both these modifications entail a three-step process of activation, conjugation, and ligation that involves three kinds of enzymes, namely, E1 activating, E2 conjugating, and E3 ligase enzymes. SUMOylation participates in organ fibrosis by modulating FXR, PML, TGF-β receptor I, Sirt3, HIF-1α, and Sirt1, while NEDDylation influences organ fibrosis by regulating cullin3, NIK, SRSF3, and UBE2M. Further investigations exhibit the therapeutic potentials of SUMOylation/NEDDylation activators and inhibitors against organ fibrosis, especially ginkgolic acid in SUMOylation and MLN4924 in NEDDylation. These results demonstrate the therapeutic effects of SUMOylation and NEDDylation against organ fibrosis and highlight their activators as well as inhibitors as potential candidates. In the future, deeper investigations of SUMOylation and NEDDylation are needed to identify novel substrates against organ fibrosis; moreover, clinical investigations are needed to determine the therapeutic effects of their activators and inhibitors that can benefit patients. This review highlights that SUMOylation and NEDDylation function as potential therapeutic targets for organ fibrosis.

Natural bioactive compounds and STAT3 against hepatocellular carcinoma: An update

Hepatocellular carcinoma (HCC) is a challenging and very fatal liver cancer. The signal transducer and activator of transcription 3 (STAT3) pathway is a crucial regulator of tumor development and are ubiquitously active in HCC. Therefore, targeting STAT3 has emerged as a promising approach for preventing and treating HCC. Various natural bioactive compounds (NBCs) have been proven to target STAT3 and have the potential to prevent and treat HCC as STAT3 inhibitors. Numerous kinds of STAT3 inhibitors have been identified, including small molecule inhibitors, peptide inhibitors, and oligonucleotide inhibitors. Due to the undesirable side effects of the conventional therapeutic drugs against HCC, the focus is shifted to NBCs derived from plants and other natural sources. NBCs can be broadly classified into the categories of terpenes, alkaloids, carotenoids, and phenols. Most of the compounds belong to the family of terpenes, which prevent tumorigenesis by inhibiting STAT3 nuclear translocation. Further, through STAT3 inhibition, terpenes downregulate matrix metalloprotease 2 (MMP2), matrix metalloprotease 9 (MMP9) and vascular endothelial growth factor (VEGF), modulating metastasis. Terpenes also suppress the anti-apoptotic proteins and cell cycle markers. This review provides comprehensive information related to STAT3 abrogation by NBCs in HCC with in vitro and in vivo evidences.

Sclareol ameliorates liver injury by inhibiting nuclear factor-kappa B/NOD-like receptor protein 3-mediated inflammation and lipid metabolism disorder in diabetic mice

Objectives: Sclareol (SCL) is a natural diterpene with anti-inflammation and antioxidant properties. This study aimed to assess the hepatoprotective effects of SCL in diabetic mice. Methods: SCL (10 mg/kg) was administered intragastrically to C57BL/6 mice with streptozotocin-induced diabetes daily for 5 weeks to evaluate its beneficial effects in liver injury. Body and liver weight and blood glucose levels were measured. Liver histopathology, fibrosis, and lipid accumulation were evaluated using hematoxylin and eosin, Masson's trichrome, and Oil Red O staining, respectively. Serum hepatic enzyme and lipid levels were measured using an automatic biochemical analyzer. Hepatocellular apoptosis was measured using the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay. Oxidative stress markers and reactive oxygen species (ROS) were measured using appropriate assay kits. The effects of sclareol on inflammation and lipid metabolism was evaluated by enzyme-linked immunosorbent assay (ELISA), immunohistochemical analysis, and Western blot assays. Results: SCL significantly decreased serum liver enzymes and lipids levels, and alleviated adipogenesis and fibrosis. Moreover, the protein levels of acetyl-CoA carboxylase and sterol response element-binding protein 1 were downregulated, whereas the expression of carnitine palmitoyl transferase 1 was upregulated. SCL increased the antioxidant activity, and decreased ROS levels. SCL alleviated hepatic mitochondrial damage. Furthermore, SCL inhibited Kupffer cell infiltration and reduced serum inflammatory cytokine levels. SCL significantly downregulated the protein expression of nuclear factor-kappa B (NF-κB) P65, NOD-like receptor protein 3 (NLRP3), caspase 1, and interleukin-1β. Conclusions: Our findings suggest that SCL improves diabetes-induced liver injury by alleviating the NF-κB/NLRP3-mediated inflammation and lipid metabolism disorder.