Chemical constitutes from Tuber indicum with immunosuppressive activity uncovered by transcriptome analysis.

Three previously undescribed compounds including a polyketide (1) and two lactams (2 and 3) were obtained from Tuber indicum. The structures of new findings were elucidated by HRESIMS, NMR as well as NMR and ECD calculations. Transcriptome analysis through RNA-seq revealed that compound 2 exhibits immunosuppressive activity. Lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages were employed as a model to explore the effect of these compounds in immunosuppressive activity. The results showed that 2 could reduce the generation of inflammatory mediators including nitric oxide (NO), reactive oxygen species (ROS), interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), cyclooxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS). Western blotting analysis demonstrated that 2 could suppressed the PI3K pathway by decreasing the levels of p-PI3K and p-Akt, while increasing the levels of p-PTEN. The anti-inflammatory activity of 2 was further confirmed using a zebrafish in vivo model.

Trichodimerol inhibits inflammation through suppression of the nuclear transcription factor-kappaB/NOD-like receptor thermal protein domain associated protein 3 signaling pathway.

Excessive inflammation causes chronic diseases and tissue damage. Although there has been drug treatment, its side effects are relatively large. Searching for effective anti-inflammatory drugs from natural products has become the focus of attention. First isolated from Trichoderma longibraciatum, trichodimerol is a natural product with TNF inhibition. In this study, lipopolysaccharide (LPS)-induced RAW264.7 macrophages were used as a model to investigate the anti-inflammatory activity of trichodimerol. The results of nitric oxide (NO) detection, enzyme-linked immunosorbent assay (ELISA), and reactive oxygen species (ROS) showed that trichodimerol could reduce the production of NO, ROS, and the proinflammatory cytokines interleukin (IL)-6 and tumor necrosis factor (TNF)-α. Western blotting results showed that trichodimerol could inhibit the production of inflammatory mediators such as cyclooxygenase (COX)-2 and inducible nitric oxide synthase (iNOS) and the protein expression of nuclear transcription factor-kappaB (NF-κB), p-IKK, p-IκB, Toll-like receptor 4 (TLR4), NOD-like receptor thermal protein domain associated protein 3 (NLRP3), cysteinyl aspartate specific proteinase (Caspase)-1, and ASC, which indicated that trichodimerol may inhibit inflammation through the NF-κB and NLRP3 pathways. At the same time, molecular docking showed that trichodimerol can directly combine with the TLR4-MD2 complex. Hence, trichodimerol inhibits inflammation by obstructing the interaction between LPS and the TLR4-MD2 heterodimer and suppressing the downstream NF-κB and NLRP3 pathways.

N-acetyldopamine dimer inhibits neuroinflammation through the TLR4/NF-κB and NLRP3/Caspase-1 pathways.

Neuroinflammation mediated by microglia is an important pathophysiological mechanism in neurodegenerative diseases. However, there is a lack of effective drugs to treat neuroinflammation. N-acetyldopamine dimer (NADD) is a natural compound from the traditional Chinese medicine Isaria cicada. In our previous study, we found that NADD can attenuate DSS-induced ulcerative colitis by suppressing the NF-κB and MAPK pathways. Does NADD inhibit neuroinflammation, and what is the target of NADD? To answer this question, lipopolysaccharide (LPS)-stimulated BV-2 microglia was used as a cell model to investigate the effect of NADD on neuroinflammation. Nitric oxide (NO) detection, reactive oxygen species (ROS) detection and enzyme-linked immunosorbent assay (ELISA) results show that NADD attenuates inflammatory signals and proinflammatory cytokines in LPS-stimulated BV-2 microglia, including NO, ROS, tumor necrosis factor (TNF)-α, interleukin (IL)-1ß and interleukin-6 (IL-6). Western blot analysis show that NADD inhibits the protein levels of Toll-like receptor 4 (TLR4), nuclear factor kappa-B (NF-κB), NOD-like receptor thermal protein domain associated protein 3 (NLRP3), ASC and cysteinyl aspartate specific proteinase (Caspase)-1, indicating that NADD may inhibit neuroinflammation through the TLR4/NF-κB and NLRP3/Caspase-1 signaling pathways. In addition, surface plasmon resonance assays and molecular docking demonstrate that NADD binds with TLR4 directly. Our study reveals a new role of NADD in inhibiting the TLR4/NF-κB and NLRP3/Caspase-1 pathways, and shows that TLR4-MD2 is the direct target of NADD, which may provide a potential therapeutic candidate for the treatment of neuroinflammation.

Alteration of MDM2 by the Small Molecule YF438 Exerts Antitumor Effects in Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) exhibits a high mortality rate and is the most aggressive subtype of breast cancer. As previous studies have shown that histone deacetylases (HDAC) may represent molecular targets for TNBC treatment, we screened a small library of synthetic molecules and identified a potent HDAC inhibitor (HDACi), YF438, which exerts effective anti-TNBC activity both in vitro and in vivo. Proteomic and biochemical studies revealed that YF438 significantly downregulated mouse double minute 2 homolog (MDM2) expression. In parallel, loss of MDM2 expression or blocking MDM2 E3 ligase activity rendered TNBC cells less sensitive to YF438 treatment, revealing an essential role of MDM2 E3 ligase activity in YF438-induced inhibition of TNBC. Mechanistically, YF438 disturbed the interaction between HDAC1 and MDM2, induced the dissociation of MDM2-MDMX, and subsequently increased MDM2 self-ubiquitination to accelerate its degradation, which ultimately inhibited growth and metastasis of TNBC cells. In addition, analysis of clinical tissue samples demonstrated high expression levels of MDM2 in TNBC, and MDM2 protein levels closely correlated with TNBC progression and metastasis. Collectively, these findings show that MDM2 plays an essential role in TNBC progression and targeting the HDAC1-MDM2-MDMX signaling axis with YF438 may provide a promising therapeutic option for TNBC. Furthermore, this novel underlying mechanism of a hydroxamate-based HDACi in altering MDM2 highlights the need for further development of HDACi for TNBC treatment. SIGNIFICANCE: This study uncovers the essential role of MDM2 in TNBC progression and suggests that targeting the HDAC1-MDM2-MDMX axis with a hydroxamate-based HDACi could be a promising therapeutic strategy for TNBC.

Erratum: Blood TfR+ exosomes separated by a pH-responsive method deliver chemotherapeutics for tumor therapy: Erratum.

[This corrects the article DOI: 10.7150/thno.37220.].

The Development Process: from SAHA to Hydroxamate HDAC Inhibitors with Branched CAP Region and Linear Linker.

Histone deacetylases (HDACs) belong to a group of epigenetic regulatory enzymes that participate in modulating the acetylation level of histone lysine residues as well as non-histone proteins, and they play a key role in the regulation of gene expression. HDACs are potential anticancer drug targets highly expressed in various kinds of cancer cells. So far, five small molecules targeting HDACs have been approved for the therapy of cancer, and over 20 inhibitors of HDACs are under different phases of clinical trials. Among them, hydroxamate-based HDAC inhibitors (HDACis) represent a well-investigated series of chemical entities. The current review covers the recent progress in the discovery process, form SAHA to hydroxamate HDAC inhibitors with branched CAP region and linear linker. At the same time, the pharmacological and structure-activity relationship (SAR) studies of the specific derivatives from SAHA and the HDACis with branched CAP region and linear linker are also introduced.

Blood TfR+ exosomes separated by a pH-responsive method deliver chemotherapeutics for tumor therapy.

Blood transferrin receptor-positive (TfR+) exosomes are a kind of optimized drug delivery vector compared with other kinds of exosomes due to their easy access and high bio-safety. Their application facilitates the translation from bench to bedside of exosome-based delivery vehicles. Methods: In this study, a pH-responsive superparamagnetic nanoparticles cluster (denoted as SMNC)-based method was developed for the precise and mild separation of blood TfR+ exosomes. Briefly, multiple superparamagnetic nanoparticles (SPMNs) labeled with transferrins (Tfs) could precisely bind to blood TfR+ exosomes to form an exosome-based cluster due to the specific recognition of TfR by Tf. They could realize the precise magnetic separation of blood TfR+ exosomes. More importantly, the pH-responsive dissociation characteristic of Tf and TfR led to the mild collapse of clusters to obtain pure blood TfR+ exosomes. Results: Blood TfR+ exosomes with high purity and in their original state were successfully obtained through the pH-responsive SMNC-based method. These can load Doxorubicin (DOX) with a loading capacity of ~10% and dramatically increase the tumor accumulation of DOX in tumor-bearing mice because of their innate passive-targeting ability. In addition, blood TfR+ exosomes changed the biodistribution of DOX leading to the reduction of side effects. Compared with free DOX, DOX-loaded blood TfR+ exosomes showed much better tumor inhibition effects on tumor-bearing mice. Conclusion: Taking advantage of the pH-responsive binding and disaggregation characteristics of Tf and TfR, the SMNC-based method can precisely separate blood TfR+ exosomes with high purity and in their original state. The resulting blood TfR+ exosomes showed excellent bio-safety and enable the efficient delivery of chemotherapeutics to tumors, facilitating the clinical translation of exosome-based drug delivery systems.