Biosynthesis of fungal terpenoids.

Covering: up to August 2023Terpenoids, which are widely distributed in animals, plants, and microorganisms, are a large group of natural products with diverse structures and various biological activities. They have made great contributions to human health as therapeutic agents, such as the anti-cancer drug paclitaxel and anti-malarial agent artemisinin. Accordingly, the biosynthesis of this important class of natural products has been extensively studied, which generally involves two major steps: hydrocarbon skeleton construction by terpenoid cyclases and skeleton modification by tailoring enzymes. Additionally, fungi (Ascomycota and Basidiomycota) serve as an important source for the discovery of terpenoids. With the rapid development of sequencing technology and bioinformatics approaches, genome mining has emerged as one of the most effective strategies to discover novel terpenoids from fungi. To date, numerous terpenoid cyclases, including typical class I and class II terpenoid cyclases as well as emerging UbiA-type terpenoid cyclases, have been identified, together with a variety of tailoring enzymes, including cytochrome P450 enzymes, flavin-dependent monooxygenases, and acyltransferases. In this review, our aim is to comprehensively present all fungal terpenoid cyclases identified up to August 2023, with a focus on newly discovered terpenoid cyclases, especially the emerging UbiA-type terpenoid cyclases, and their related tailoring enzymes from 2015 to August 2023.

Mechanistic characterisation of a fungal fusicoccane-type diterpene synthase involved in the biosynthesis of talaro-7,13-diene.

The cyclisation mechanism of the fungal fusicoccane (FC)-type diterpene synthase (DTS) TadA was investigated by extensive isotopic labelling experiments, and the pH-dependency of the product selectivity of this enzyme was explored. These studies provide new insights into the cyclisation mechanisms of FC-type DTSs.

Identification of three novel P450 enzymes involved in the oxidative modification of a newly discovered fusicoccane diterpene.

Fusicoccane (FC)-type diterpenoids are a class of diterpenoids characterized by a unique 5-8-5 ring system and exhibit diverse biological activities. Recently, we identified a novel FC-type diterpene synthase MgMS, which produces a myrothec-15(17)-en-7-ol (1) hydrocarbon skeleton, however, its tailoring congeners have not been elucidated. Here, we discovered two additional gene clusters Bn and Np, each encoding a highly homologous terpene synthase to MgMS but distinct tailoring enzymes. Heterologous expression of the terpene synthases BnMS and NpMS yielded the same product as MgMS. Subsequent introduction of three P450 enzymes MgP450, BnP450 and NpP450 from individual gene clusters resulted in four new FC-type diterpenoids 2-5. Notably, MgP450 serves as the first enzyme responsible for hydroxylation of the C19 methyl group, whereas NpP450 functions as a multifunctional P450 enzyme involved in the oxidations at C5, C6, and C19 positions of the 5-8-5 tricyclic skeleton. C5 oxidation of the hydrocarbon skeleton 1 led to broadening of the NMR signals and incomplete spectra, which was resolved by high-temperature NMR spectral analysis.

Codelivery of ERCC2 small interfering RNA and cisplatin with macrophage-derived mimetic nanovesicles for enhanced bladder cancer treatment.

Cisplatin-based chemotherapy plays a vital role in the management of muscle-invasive bladder cancer (MIBC); however, off-tumor toxicity and resistance often lead to cancer recurrence and eventual treatment failure. The loss of function of the nucleotide excision repair gene excision repair cross-complementing rodent repair deficiency gene 2 ( ERCC2 ) in cancer cells correlates with sensitivity to cisplatin, while its overexpression causes cisplatin resistance. Small interfering RNA (siRNA) knockdown of ERCC2 combined with cisplatin treatment may improve therapeutic outcomes in patients with bladder cancer. Here, we aimed to develop macrophage-derived mimetic nanovesicles (MNVs) as a nanoplatform for the simultaneous delivery of cisplatin and ERCC2 siRNA for enhancing the efficacy of bladder cancer chemotherapy. The cellular uptake, gene down-regulation, tumor inhibition effects, and biosafety of the synthesized nanodrugs (MNV-Co) as a synergistic therapeutic strategy for MIBC were evaluated in vitro and in vivo . The results indicated high efficacy of MNV-Co against MIBC and low off-tumor toxicity. Furthermore, by down-regulating ERCC2 mRNA and protein levels, MNV-Co improved chemosensitivity, promoted cancer cell apoptosis, and effectively suppressed tumor growth. This study presents a potential approach for delivering cisplatin and ERCC2 siRNA concurrently to treat bladder cancer using a biomimetic nanosystem.

Isolation of new compounds related to xyloketals biosynthesis implies an alternative pathway for furan-fused-chromene formation.

In fungi, there is a rare group of natural products harboring the 2,3,3a,9a-tetrahydro-4H-furo[2,3-b]chromene skeleton, represented by xyloketal B, which display a wide range of biological activities and have drawn significant attention. In this work, four new analogues simpliketals A-D (1-4), as well as two other new compounds simplilactones A and B (5 and 6), were isolated from Simplicillium sp. AHK071-01. Their structures were elucidated by extensive NMR spectroscopic methods, 13C NMR calculation, single-crystal X-ray diffraction, and ECD calculation. In addition, five known compounds (7-11) including alboatrin (7) were also obtained. Based on the structural similarity of the above compounds, we inferred that compounds 5, 6, and 8-11 might be biosynthetically related with 1-4 and 7, which allowed us to propose an alternative biosynthetic route to generate the furan-fused chromene skeleton of this class of compounds, instead of a previously presumed polyketide-terpenoid hybrid pathway. Finally, cytotoxicity assays showed that 1-4 exhibited weak inhibitory activity on PANC-1 cells and that 2 and 3 possessed moderate activity against SH-SY5Y cells.

Acyl carrier protein tag can enhance tobacco etch virus protease stability and promote its covalent immobilisation.

Fusion expression is widely employed to enhance the solubility of recombinant proteins. However, removal of the fusion tag is often required due to its potential impact on the structure and activity of passenger proteins. Tobacco etch virus (TEV) protease is widely used for this purpose due to its stringent sequence recognition. In the present work, fusion to the acyl carrier protein from E. coli fatty acid synthase (ACP) significantly increased the yield of recombinant soluble TEV, and the ACP tag also greatly improved TEV stability. The cleavage activity of TEV was not affected by the ACP fusion tag, and ACP-TEV retained high activity, even at unfavourable pH values. Moreover, ACP-TEV could be efficiently modified by co-expressed E. coli holo-ACP synthase (AcpS), leading to covalent attachment of 4'-phosphopantetheine (4'-PP) group to ACP. The sulfhydryl group of the long, flexible 4'-PP chain displayed high specific reactivity with iodoacetyl groups on the solid support. Thus, TEV could be immobilised effectively and conveniently via the active holo-ACP, and immobilised TEV retained high cleavage activity after a long storage period and several cycles of reuse. As a low-cost and recyclable biocatalyst, TEV immobilised by this method holds promise for biotechnological research and development. KEY POINTS: • The ACP tag greatly increased the soluble expression and stability of TEV protease. • The ACP tag did not affect the cleavage activity of TEV. • The holo-ACP Tag effectively mediated the covalent immobilisation of TEV.

Characterization of a new fusicoccane-type diterpene synthase and an associated P450 enzyme.

Fusicoccane-type terpenoids are a subgroup of diterpenoids featured with a unique 5-8-5 ring system. They are widely distributed in nature and possess a variety of biological activities. Up to date, only five fusicoccane-type diterpene synthases have been identified. Here, we identify a two-gene biosynthetic gene cluster containing a new fusicoccane-type diterpene synthase gene tadA and an associated cytochrome P450 gene tadB from Talaromyces wortmannii ATCC 26942. Heterologous expression reveals that TadA catalyzes the formation of a new fusicoccane-type diterpene talaro-7,13-diene. D2O isotope labeling combined with site-directed mutagenesis indicates that TadA might employ a different C2,6 cyclization strategy from the known fusicoccane-type diterpene synthases, in which a neutral intermediate is firstly formed and then protonated by an environmental proton. In addition, we demonstrate that the associated cytochrome P450 enzyme TadB is able to catalyze multiple oxidation of talaro-7,13-diene to yield talaro-6,13-dien-5,8-dione.

Integrated meta-analysis, network pharmacology, and molecular docking to investigate the efficacy and potential pharmacological mechanism of Kai-Xin-San on Alzheimer's disease.

CONTEXT: Kai-Xin-San (KXS) has been used to treat Alzheimer's disease (AD) for thousands of years. However, no quantitative data regarding AD treatment using KXS are available. Moreover, its active compounds and mechanism of action for the treatment of AD remain largely unclear. OBJECTIVES: To evaluate the efficacy and the potential pharmacological mechanisms of KXS in AD treatment. MATERIALS AND METHODS: A systematic collection of KXS experiments was conducted from PubMed, Web of Science, Embase, CNKI, VIP, and Wanfang Data up to February, 2020. Review Manager 5 software was used for meta-analysis. In network pharmacology, components of KXS were screened, AD-related genes were then identified and the 'component-target-pathway' network constructed. Molecular docking was finally employed for in silico simulation matching between representative KXS compounds and their target genes. RESULTS: Meta-analysis revealed that KXS improves the cognitive benefits in AD models by reducing the time of escape latency (SMD = -16.84) as well as increasing the number of cross-platform (SMD = 2.56) and proportion of time in the target quadrant (SMD = 7.52). Network pharmacology identified 25 KXS active compounds and 44 genes targets. DRD2, MAOA, ACHE, ADRA2A and CHRM2 were core target proteins. Besides, 22 potential pathways of KXS were identified, like cholinergic synapses, the cGMP/PKG pathway and calcium signalling. Molecular docking showed that stigmasterol, aposcopolamine and inermin can closely bind three targets (ACHE, ADRA2A and CHRM2). DISCUSSION AND CONCLUSION: These findings suggest that KXS exerts effect on AD through multi-target, multi-component and multi-pathway mechanism. Future studies may explore the active components of KXS.

Biosynthesis of an anti-tuberculosis sesterterpenoid asperterpenoid A.

A putative three-gene cluster for asperterpenoid A was identified. Step-wise reconstitution of this gene cluster in Aspergillus oryzae reveals that astC encodes a sesterterpene cyclase to synthesize preasperterpenoid A, which is dually oxidized by a P450 enzyme AstB to give asperterpenoid A along with a minor product asperterpenoid B, and asperterpenoid A is further oxidized by another P450 eznyme AstA to afford a new sesterterpenoid asperterpenoid C. Unexpectedly, asperterpenoids A and B, but not the final product asperterpenoid C, exhibit potent inhibitory activity against Mycobacterium tuberculosis protein tyrosine phosphatase B with IC50 values of 3-6 µM.

[The Research on Reinspection Problems in Supervisory Sampling Inspection for Medical Devices].

Supervisory sampling inspection is one of the administrative supervision measures for medical devices. As the reinspection work affects the final conclusion of sampling inspection, inappropriate overturn during the reinspection has already impaired the impartiality and authority of the supervisory inspection work. By the statistics of survey materials, this article analyzes the reasons for requesting reinspection and making overturns, and proposes a scheme for eliminating the interference factors such as the understanding divergences and the defects of standards, the inspection capacity and the issues of sampled devices, etc. To enhance the authoritative of reinspection, this article also proposes principals of evasion, precedence, arbitration and assessment, and the improvement of the reinspection workflow in order to make the reinspection work more appropriate, more efficient and more impartial.

[A Drug Delivery Device for Drug-eluting Stents Simulating the Cardiovascular Blood Flow Pattern].

A novel drug delivery device simulating the cardiovascular bloodfl ow pattern was introduced. The device was used to simulate the in vivo drug release in the drug-eluting stents. The results regarding the drug release rate were subject to the pattern from in vivo measurement. Therefore, the device was validated as a measurement method for in vivo drug release rate.

[The Development and Application of the Orthopaedics Implants Failure Database Software Based on WEB].

This article develops a new failure database software for orthopaedics implants based on WEB. The software is based on B/S mode, ASP dynamic web technology is used as its main development language to achieve data interactivity, Microsoft Access is used to create a database, these mature technologies make the software extend function or upgrade easily. In this article, the design and development idea of the software, the software working process and functions as well as relative technical features are presented. With this software, we can store many different types of the fault events of orthopaedics implants, the failure data can be statistically analyzed, and in the macroscopic view, it can be used to evaluate the reliability of orthopaedics implants and operations, it also can ultimately guide the doctors to improve the clinical treatment level.

[Development of testing device for dynamic performance of radial artery pulse force transducer and electropulsogragh].

Based on the dynamic performance of radial force sensor detection and TCM pulse waveform technology, the paper described a kind of testing equipment being developed which tests both radial force sensor performance and the dynamic performance of the instrument of pulse detection. The device covers requirements for static and dynamic performance test of the radial artery pulse wave force sensor and pulse diagnosis instrument, thus it makes a change to compute frequency response of the sensor by directly measurement.

[Particle evaluation of cardiovascular stents].

This paper has briefly introduced the definition, classification, harms, sources and control of particles, lists the particle evaluation method of coronary stents. And the development trend of particle evaluation method of coronary stents is also analyzed.

[Optimization based on finite element technique of nitinol stent].

The finite element method was used for simulating the mechanical performance and fatigue safety of three different structures of Nitinol stent. According to the actual situation, after proposing reasonable assumptions and simplification, the geometry model and finite element model establishment, material mode selection and boundary condition setting are completed. The strain and fatigue life of different stent edges wide (omega) or strut angle (theta) are computed. The result can provide a valuable reference for the optimal design of stent.

Molecular crosstalk between circadian clock and NLRP3 inflammasome signaling in Parkinson's disease.

Parkinson's disease (PD) is one of the most common neurodegenerative diseases. Research has recently found that both animal models and patients with PD have circadian dysfunction, accompanied by abnormal expression of circadian genes and proteins, which implies that the circadian clock plays a crucial role in PD etiopathogenesis. In addition, a strong relationship between NLRP3 inflammasome signaling and PD has been observed. Meanwhile, the activation of the NLRP3 inflammasome is highly relevant to dysfunctions of the molecular clock. Therefore, alleviating the neuroinflammation caused by NLRP3 inflammasome signaling by adjusting the abnormal molecular clock may be a potential strategy for preventing and treating PD. In this article, we have reviewed the potential or direct relationship between abnormalities of the circadian clock and NLRP3 inflammasome signaling in PD.

Upregulation of NPC1 and its association with poor prognosis in gastric cancer.

BACKGROUND: The Niemann-Pick disease type C1 (NPC1) protein plays a pivotal role in lipid transport, particularly free cholesterol, within lysosomal/late endosomal membranes. Previous studies have highlighted NPC1 as a promising target for cholesterol trafficking and cancer therapy. Nevertheless, the expression of NPC1 in gastric cancer (GC) and its clinical implications remain unexplored. This study aims to investigate NPC1 expression in GC and its correlation with patient prognosis. METHODS: NPC1 expression levels in GC and normal tissues were assessed using the GEPIA database, and survival analysis was conducted via Kaplan‒Meier Plotter. Evaluation of potential biological effects of NPC1 in GC by protein-protein interaction network and GO, KEGG bioenrichment analysis. Immunohistochemistry was performed on surgical samples collected from 306 GC patients. Correlations between NPC1 expression, clinical characteristics, and patient prognosis were analyzed. RESULTS: NPC1 mRNA expression was elevated in GC tissues compared to normal tissues (P < 0.05) and significantly associated with poorer prognosis. In our cohort of 306 patients, NPC1 exhibited significant upregulation in GC versus adjacent normal tissues (P = 0.031). High NPC1 expression correlated with adverse clinical characteristics, including lymph node metastasis, distant metastasis, and advanced TNM stage (all P < 0.05). Patients with high NPC1 expression experienced notably shorter overall survival (P < 0.001), particularly in stages III and IV (P = 0.003). Multivariate Cox regression analysis identified high NPC1 expression as an independent prognostic factor for GC patients (HR 1.57, 95% CI 1.14-2.18, P = 0.006). Lastly, an optimized nomogram incorporating NPC1, tumor size, and TNM stage was constructed. CONCLUSIONS: NPC1 expression is upregulated in GC and serves as a pivotal prognostic factor for adverse outcomes in GC patients.

Echinacoside exerts neuroprotection via suppressing microglial α-synuclein/TLR2/NF-κB/NLRP3 axis in parkinsonian models.

BACKGROUND: Echinacoside (ECH), a natural active compound, was found to exert neuroprotection in Parkinson's disease (PD). However, the underlying molecular mechanisms remain controversial. PURPOSE: This study aimed to explore the roles of ECH in PD and its engaged mechanisms. CONCLUSION: In vivo, MPTP was adapted to construct subacute PD mouse model to explore the regulation of ECH on NLRP3 inflammasome. In vitro, α-synuclein (α-syn)/MPP+ was used to mediate the activation of NLRP3 inflammasome in BV2 cells, and the mechanism of ECH regulation of it was explored with molecular docking, immunofluorescence, Western blotting, and small molecule inhibitors. CONCLUSION: The activation of microglial NLRP3 inflammasome could be evoked by MPTP in vitro, but its toxic metabolite MPP+ alone cannot trigger the activation of NLRP3 inflammasome in vitro, which requires α-synuclein (α-syn) priming. Exogenous α-syn could evoke microglial TLR2/NF-κB/NLRP3 axis, playing the priming role in MPP+ -mediated NLRP3 inflammasome activation. ECH can suppress the upregulation of α-syn in MPTP-treated mice and BV2 microglia. It can also suppress the activation of the TLR2/NF-κB/NLRP3 axis induced by α-syn. CONCLUSION: ECH exerts neuroprotective effects by downregulating the TLR2/NF-κB/NLRP3 axis via reducing the expression of α-syn in the PD models.

Baicalin exerts neuroprotective actions by regulating the Nrf2-NLRP3 axis in toxin-induced models of Parkinson's disease.

Baicalin, a potent anti-oxidative and anti-inflammatory flavonoid compound derived from Scutellaria baicalensis, has emerged as a neuroprotective agent. However, the mechanisms by which baicalin is neuroprotective in Parkinson's disease (PD) remain unclear. In this research, α-syn/MPP+ and MPTP were used to establish PD models in BV2 cells and C57BL/6 mice, respectively. The effect and mechanism of action of baicalin in PD were investigated by Western blotting, RT-qPCR, ELISA, Immunohistochemistry (IHC) staining, Immunofluorescence (IF) staining, HPLC and methods. Results demonstrate that baicalin mitigates oxidative stress, microglia activation and inflammatory response caused by α-syn/MPP+ and MPTP. It protects against dopaminergic neuron loss and relieves motor deficits. Meanwhile, baicalin not only significantly up-regulates the expression of Nrf2 and its downstream antioxidant enzyme, but also suppresses the activation of NLRP3 inflammasome simultaneously. Notably, the beneficial effects of baicalin in PD treatment are blocked by Nrf2 knockdown. This research reveals that baicalin may exert neuroprotective effects in PD treatment by suppressing the activation of NLRP3 inflammasome and it is dependent on the Nrf2-mediated antioxidative response.

ROS-responsive MSC-derived Exosome Mimetics Carrying MHY1485 Alleviate Renal Ischemia Reperfusion Injury through Multiple Mechanisms.

Renal ischemia reperfusion (IR) injury is a prevalent inflammatory nephropathy in surgeries such as renal transplantation or partial nephrectomy, damaging renal function through inducing inflammation and cell death in renal tubules. Mesenchymal stromal/stem cell (MSC)-based therapies, common treatments to attenuate inflammation in IR diseases, fail to exhibit satisfying effects on cell death in renal IR. In this study, we prepared MSC-derived exosome mimetics (EMs) carrying the mammalian target of the rapamycin (mTOR) agonist to protect kidneys in proinflammatory environments under IR conditions. The thioketal-modified EMs carried the mTOR agonist and bioactive molecules in MSCs and responsively released them in kidney IR areas. MSC-derived EMs and mTOR agonists protected kidneys synergistically from IR through alleviating inflammation, apoptosis, and ferroptosis. The current study indicates that MSC-TK-MHY1485 EMs (MTM-EM) are promising therapeutic biomaterials for renal IR injury.