Skeletal Transformations of Terpenoid Forskolin Employing an Oxidative Rearrangement Strategy.

The skeletal transformations of diterpenoid forskolin were achieved by employing an oxidative rearrangement strategy. A library of 36 forskolin analogues with structural diversity was effectively generated. Computational analysis shows that 12 CTD compounds with unique scaffolds and ring systems were produced during the course of this work.

The relationship between oxidative stress and apoptosis of histopathological changes in the ovary made by mad honey containing grayanotoxin.

The purpose of this study is to determine the effects of grayanotoxin in mad honey on ovarian tissue folliculogenesis in terms of cell death and nitric oxide expression. Three groups of 18 female Sprague-Dawley rats were formed. The first group received mad honey (80 mg/kg), the second group received normal honey (80 mg/kg), and the third group was the control. The first and second groups received normal and mad honey by oral gavage for 30 days before being sacrificed under anesthesia. Caspase 3 immunostaining showed a moderate to strong response, particularly in the mad honey group. In the mad honey group, immunostaining for caspase 8 and caspase 9 revealed a moderate immunoreaction in the granulosa cells of the Graaf follicles. The majority of Graaf follicles exhibited TUNEL positive in the mad honey group. The iNOS immunoreaction revealed a high level of expression in the mad honey group. In all three groups, eNOS immunostaining showed weak reactivity. According to the findings of apoptotic and nitric oxide marker expression, it was determined that mad honey may result in an increase in follicular atresia in ovarian follicles when compared to normal honey and control groups.

Jolkinolide B synergistically potentiates the antitumor activity of GPX4 inhibitors via inhibiting TrxR1 in cisplatin-resistant bladder cancer cells.

Glutathione peroxidase 4 (GPX4) is a promising anticancer therapeutic target; however, the application of GPX4 inhibitors (GPX4i) is limited owing to intrinsic or acquired drug resistance. Hence, understanding the mechanisms underlying drug resistance and discovering molecules that can overcome drug resistance are crucial. Herein, we demonstrated that GPX4i killed bladder cancer cells by inducing lipid reactive oxygen species-mediated ferroptosis and apoptosis, and cisplatin-resistant bladder cancer cells were also resistant to GPX4i, representing a higher half-maximal inhibitory concentration value than that of parent bladder cancer cells. In addition, thioredoxin reductase 1 (TrxR1) overexpression was responsible for GPX4i resistance in cisplatin-resistant bladder cancer cells, and inhibiting TrxR1 restored the sensitivity of these cells to GPX4i. In vitro and in vivo studies revealed that Jolkinolide B (JB), a natural diterpenoid and previously identified as a TrxR1 inhibitor, potentiated the antiproliferative efficacy of GPX4i (RSL3 and ML162) against cisplatin-resistant bladder cancer cells. Furthermore, GPX4 knockdown and inhibition could augment JB-induced paraptosis and apoptosis. Our results suggest that inhibiting TrxR1 can effectively improve GPX4 inhibition-based anticancer therapy. A combination of JB and GPX4i, which is well-tolerated and has several anticancer mechanisms, may serve as a promising therapy for treating bladder cancer.

A high-content screen of FDA approved drugs to enhance CAR T cell function: ingenol-3-angelate improves B7-H3-CAR T cell activity by upregulating B7-H3 on the target cell surface via PKCα activation.

BACKGROUND: CAR T cell therapy is a promising approach to improve outcomes and decrease toxicities for patients with cancer. While extraordinary success has been achieved using CAR T cells to treat patients with CD19-positive malignancies, multiple obstacles have so far limited the benefit of CAR T cell therapy for patients with solid tumors. Novel manufacturing and engineering approaches show great promise to enhance CAR T cell function against solid tumors. However, similar to single agent chemotherapy approaches, CAR T cell monotherapy may be unable to achieve high cure rates for patients with difficult to treat solid tumors. Thus, combinatorial drug plus CAR T cell approaches are likely required to achieve widespread clinical success. METHODS: We developed a novel, confocal microscopy based, high-content screen to evaluate 1114 FDA approved drugs for the potential to increase expression of the solid tumor antigen B7-H3 on the surface of osteosarcoma cells. Western blot, RT-qPCR, siRNA knockdown and flow cytometry assays were used to validate screening results and identify mechanisms of drug-induced B7-H3 upregulation. Cytokine and cytotoxicity assays were used to determine if drug pre-treatment enhanced B7-H3-CAR T cell effector function. RESULTS: Fifty-five drugs were identified to increase B7-H3 expression on the surface of LM7 osteosarcoma cells using a novel high-content, high-throughput screen. One drug, ingenol-3-angelate (I3A), increased B7-H3 expression by up to 100%, and was evaluated in downstream experiments. Validation assays confirmed I3A increased B7-H3 expression in a biphasic dose response and cell dependent fashion. Mechanistic studies demonstrated that I3A increased B7-H3 (CD276) mRNA, total protein, and cell surface expression via protein kinase C alpha activation. Functionally, I3A induced B7-H3 expression enhanced B7-H3-CAR T cell function in cytokine production and cytotoxicity assays. CONCLUSIONS: This study demonstrates a novel high-content and high-throughput screen can identify drugs to enhance CAR T cell activity. This and other high-content technologies will pave the way to develop clinical trials implementing rational drug plus CAR T cell combinatorial therapies. Importantly, the technique could also be repurposed for an array of basic and translational research applications where drugs are needed to modulate cell surface protein expression.

Feedback regulation of the isoprenoid pathway by SsdTPS overexpression has the potential to enhance plant tolerance to drought stress.

In order to maintain the dynamic physiological balance, plants are compelled to adjust their energy metabolism and signal transduction to cope with the abiotic stresses caused by complex and changeable environments. The diterpenoid natural compound and secondary metabolites, sclareol, derived from Salvia sclarea, has gained significant attention owing to its economic value as a spice material and diverse physiological activities. Here, we focused on the roles and regulatory mechanisms of the sclareol diterpene synthase gene SsdTPS in the resistance of S. sclarea to abiotic stresses. Our results suggested that abiotic stresses could induce the response and upregulation of SsdTPS expression and isoprenoid pathway in S. sclarea. Ectopic expression of SsdTPS conferred drought tolerance in transgenic Arabidopsis, compared with wild-type. Overexpression of SsdTPS enhanced the transcription of ABA signal transduction synthetic regulators and induced the positive feedback upregulating key regulatory genes in the MEP pathway, thereby promoting the increase of ABA content and improving drought tolerance in transgenic plants. In addition, SsdTPS-overexpressed transgenic Arabidopsis improved the responses of stomatal regulatory genes and ROS scavenging enzyme activities and gene expression to drought stress. This promoted the stomatal closure and ROS reduction, thus enhancing water retention capacity and reducing oxidative stress damage. These findings unveil the potentially positive role of SsdTPS in orchestrating multiple regulatory mechanisms and maintaining homeostasis for improved abiotic stress resistance in S. sclarea, providing a novel insight into strategies for promoting drought resistance and cultivating highly tolerant plants.

Nitrogen Sources Reprogram Carbon and Nitrogen Metabolism to Promote Andrographolide Biosynthesis in Andrographis paniculata (Burm.f.) Nees Seedlings.

Carbon (C) and nitrogen (N) metabolisms participate in N source-regulated secondary metabolism in medicinal plants, but the specific mechanisms involved remain to be investigated. By using nitrate (NN), ammonium (AN), urea (UN), and glycine (GN), respectively, as sole N sources, we found that N sources remarkably affected the contents of diterpenoid lactone components along with C and N metabolisms reprograming in Andrographis paniculata, as compared to NN, the other three N sources raised the levels of 14-deoxyandrographolide, andrographolide, dehydroandrographolide (except UN), and neoandrographolide (except AN) with a prominent accumulation of farnesyl pyrophosphate (FPP). These N sources also raised the photosynthetic rate and the levels of fructose and/or sucrose but reduced the activities of phosphofructokinase (PFK), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), phosphoenolpyruvate carboxylase (PEPC) and pyruvate dehydrogenase (PDH). Conversely, phosphoenolpyruvate carboxykinase (PEPCK) and malate enzyme (ME) activities were upregulated. Simultaneously, citrate, cis-aconitate and isocitrate levels declined, and N assimilation was inhibited. These results indicated that AN, UN and GN reduced the metabolic flow of carbohydrates from glycolysis into the TCA cycle and downstream N assimilation. Furthermore, they enhanced arginine and GABA metabolism, which increased C replenishment of the TCA cycle, and increased ethylene and salicylic acid (SA) levels. Thus, we proposed that the N sources reprogrammed C and N metabolism, attenuating the competition of N assimilation for C, and promoting the synthesis and accumulation of andrographolide through plant hormone signaling. To obtain a higher production of andrographolide in A. paniculata, AN fertilizer is recommended in its N management.

Edge based metric dimension of various coffee compounds.

An important dietary source of physiologically active compounds, coffee also contains phenolic acids, diterpenes, and caffeine. According to a certain study, some coffee secondary metabolites may advantageously modify a number of anti-cancer defense systems. This research looked at a few coffee chemical structures in terms of edge locating numbers or edge metric size to better understand the mechanics of coffee molecules. Additionally, this research includes graph theoretical properties of coffee chemical structures. The chemicals found in coffee, such as caffeine, diterpene or cafestol, kahweol, chlorogenic, caffeic, gallotannins, and ellagitannins, are especially examined in these publications.

Jolkinolide B inhibits the progression of hepatocellular carcinoma by regulating Musashi-2 protein.

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths. However, the HCC treatment is still challenging. Herein, we aimed to reveal the anti-tumor effect of Jolkinolide B in HCC cell lines Huh-7 and SK-Hep-1. The results showed that Jolkinolide B inhibited the migration, invasion, and epithelial-to-mesenchymal transition(EMT) of HCC cells. In addition, Jolkinolide B induced HCC cell apoptosis by upregulating Bax and downregulating BCL-2 expressions. Furthermore, we demonstrated that Jolkinolide B inactivated the ß-catenin signaling and reduced Musashi-2 expression. Finally, we revealed that Musashi-2 overexpression reversed the Jolkinolide B-induced anti-HCC effect. Overall, we proved that Jolkinolide B is a potential candidate for treating HCC.

The protective effect of vitamin A palmitate eye gel on the ocular surface during general anaesthesia surgery: a randomized controlled trial.

PURPOSE: To investigate the change in tear production associated with general anesthesia and the protective effect of vitamin A palmitate eye gel on the ocular surface during general anesthesia. METHODS: This double-blind, randomized clinical trial included patients undergoing non-ophthalmic surgery under general anesthesia who randomly received vitamin A palmitate eye gel and taping for one eye (Group A, n = 60) or taping alone for the other eye (Group B, n = 60). Symptom assessment in dry eye (SANDE) score, tear film break-up time (TBUT), corneal fluorescein staining (CFS) score, and Schirmer tear test I (STT-1) were analyzed under a hand-held slit lamp before anesthesia (T0), 0.5 h postoperatively (T1), and 24 h postoperatively (T2). RESULTS: At 0.5 h postoperatively, an increase in CFS score was observed in both groups (P < 0.05 in Group A and P < 0.01 in Group B), and the participants in Group A had less corneal abrasions than those in Group B. STT-1 significantly increased in Group A (P < 0.05), while it significantly decreased in Group B (P < 0.001). The changes between the two groups were statistically significant (P < 0.001). At 24 h postoperatively, both CFS score and STT-1 almost returned to baseline levels in the two groups. In both groups, the SANDE score and TBUT showed little change at 0.5 h and 24 h postoperatively (all P > 0.05). CONCLUSION: Vitamin A palmitate eye gel effectively protected the ocular surface and aqueous supplementation during general anesthesia. TRIAL REGISTRATION: This study was registered in the Chinese Clinical Trial Registry (ChiCTR2100052140) on 20/10/2021.

Recent Advances in Grayanane Diterpenes: Isolation, Structural Diversity, and Bioactivities from Ericaceae Family (2018-2024).

Diterpenes represent one of the most diverse and structurally complex families of natural products. Among the myriad of diterpenoids, grayanane diterpenes are particularly notable. These terpenes are characterized by their unique 5/7/6/5 tetracyclic system and are exclusive to the Ericaceae family of plants. Renowned for their complex structures and broad spectrum of bioactivities, grayanane diterpenes have become a primary focus in extensive phytochemical and pharmacological research. Recent studies, spanning from 2018 to January 2024, have reported a series of new grayanane diterpenes with unprecedented carbon skeletons. These compounds exhibit various biological properties, including analgesic, antifeedant, anti-inflammatory, and inhibition of protein tyrosine phosphatase 1B (PTP1B). This paper delves into the discovery of 193 newly identified grayanoids, representing 15 distinct carbon skeletons within the Ericaceae family. The study of grayanane diterpenes is not only a deep dive into the complexities of natural product chemistry but also an investigation into potential therapeutic applications. Their unique structures and diverse biological actions make them promising candidates for drug discovery and medicinal applications. The review encompasses their occurrence, distribution, structural features, and biological activities, providing invaluable insights for future pharmacological explorations and research.

Proteomic Ligandability Maps of Spirocycle Acrylamide Stereoprobes Identify Covalent ERCC3 Degraders.

Covalent chemistry coupled with activity-based protein profiling (ABPP) offers a versatile way to discover ligands for proteins in native biological systems. Here, we describe a set of stereo- and regiochemically defined spirocycle acrylamides and the analysis of these electrophilic "stereoprobes" in human cancer cells by cysteine-directed ABPP. Despite showing attenuated reactivity compared to structurally related azetidine acrylamide stereoprobes, the spirocycle acrylamides preferentially liganded specific cysteines on diverse protein classes. One compound termed ZL-12A promoted the degradation of the TFIIH helicase ERCC3. Interestingly, ZL-12A reacts with the same cysteine (C342) in ERCC3 as the natural product triptolide, which did not lead to ERCC3 degradation but instead causes collateral loss of RNA polymerases. ZL-12A and triptolide cross-antagonized one another's protein degradation profiles. Finally, we provide evidence that the antihypertension drug spironolactone─previously found to promote ERCC3 degradation through an enigmatic mechanism─also reacts with ERCC3_C342. Our findings thus describe monofunctional degraders of ERCC3 and highlight how covalent ligands targeting the same cysteine can produce strikingly different functional outcomes.

Reprogramming the Metabolism of Yeast for High-Level Production of Miltiradiene.

Miltiradiene serves as a crucial precursor in the synthesis of various high-value abietane-type diterpenes, exhibiting diverse pharmacological activities. Previous efforts to enhance miltiradiene production have primarily focused on the mevalonate acetate (MVA) pathway. However, limited emphasis has been placed on optimizing the supply of acetyl-CoA and NADPH. In this study, we constructed a platform yeast strain for miltiradiene production by reinforcing the biosynthetic pathway of geranylgeranyl diphosphate (GGPP) and acetyl-CoA, and addressing the imbalance between the supply and demand of the redox cofactor NADPH within the cytoplasm, resulting in an increase in miltiradiene yield to 1.31 g/L. Furthermore, we conducted modifications to the miltiradiene synthase fusion protein tSmKSL1-CfTPS1. Finally, the comprehensive engineering strategies and protein modification strategies culminated in 1.43 g/L miltiradiene in the engineered yeast under shake flask culture conditions. Overall, our work established efficient yeast cell factories for miltiradiene production, providing a foothold for heterologous biosynthesis of abietane-type diterpenes.

Dehydroandrographolide facilitates M2 macrophage polarization by downregulating DUSP3 to inhibit sepsis-associated acute kidney injury.

BACKGROUND: Sepsis is perceived as lethal tissue damage and significantly increases mortality in combination with acute kidney injury (AKI). M2 macrophages play important roles in the secretion of anti-inflammatory and tissue repair mediators. We aimed to study the role of Dehydroandrographolide (Deh) in sepsis-associated AKI in vitro and in vivo through lipopolysaccharide (LPS)-induced macrophages model and cecal ligation and puncture-induced AKI mice model, and to reveal the mechanism related to M2 macrophage polarization. METHODS: Enzyme-linked immunosorbent assay kits were used to assess the levels of inflammatory factors. Expression of markers related to M1 macrophages and M2 macrophages were analyzed. Additionally, dual specificity phosphatase 3 (DUSP3) expression was tested. Cell apoptosis was evaluated by flow cytometry analysis and terminal-deoxynucleotidyl transferase-mediated nick end labeling staining. Moreover, renal histological assessment was performed by using hematoxylin and eosin staining. RESULTS: Deh reduced inflammation of THP-1-derived macrophages exposed to LPS. Besides, Deh induced the polarization of M1 macrophages to M2 and downregulated DUSP3 expression in THP-1-derived macrophages under LPS conditions. Further, DUSP3 overexpression reversed the impacts of Deh on the inflammation and M2 macrophages polarization of THP-1-derived macrophages stimulated by LPS. Additionally, human proximal tubular epithelial cells (HK-2) in the condition medium from DUSP3-overexpressed THP-1-derived macrophages treated with LPS and Deh displayed decreased viability and increased apoptosis and inflammation. The in vivo results suggested that Deh improved the renal function, ameliorated pathological injury, induced the polarization of M1 macrophages to M2, suppressed inflammation and apoptosis, and downregulated DUSP3 expression in sepsis-induced mice. CONCLUSION: Deh facilitated M2 macrophage polarization by downregulating DUSP3 to inhibit septic AKI.

New pimarane diterpenoids with antibacterial activity from fungus Arthrinium sp. ZS03.

A comprehensive chemical study of the endophytic fungus Arthrinium sp. ZS03, associated with Acorus tatarinowii Schott, yielded eleven pimarane diterpenoids (compounds 1-11), including seven novel compounds designated arthrinoids A-G (1-7). The determination of their structures and absolute configurations was achieved through extensive spectroscopic techniques, quantum chemical calculations of electronic circular dichroism (ECD), and single-crystal X-ray diffraction analysis. Furthermore, 7 demonstrated inhibitory activity against Klebsiella pneumoniae, comparable to the reference antibiotic amikacin, with a minimum inhibitory concentration (MIC) of 8 µg·mL-1.

XinJiaCongRongTuSiZiWan protects triptolide-induced rats from oxidative stress injury via mitophagy mediated PINK1/Parkin signaling pathway.

PURPOSE: XinJiaCongRongTuSiZiWan (XJCRTSZW) is a traditional Chinese medicine compound for invigorating the kidney, nourishing blood, and promoting blood circulation. This study aimed to explore the effect of XJCRTSZW on triptolide (TP)-induced oxidative stress injury. METHODS: Adult female Sprague-Dawley rats and human ovarian granulosa cell lines were treated with TP and XJCRTSZW. Hematoxylin and eosin staining, enzyme-linked immunosorbent assay, flow cytometry, CCK-8, JC-1 staining, transmission electron microscopy, reverse transcription-quantitative polymerase chain reaction, and Western blotting were performed in this study. RESULTS: XJCRTSZW treatment observably ameliorated the TP-induced pathological symptoms. Furthermore, XJCRTSZW treatment observably enhanced the TP-induced reduction of estradiol, anti-Mullerian hormone, progesterone, superoxide dismutase, ATP content, mitochondrial membrane potential, p62, and Hsp60 mRNA, and protein levels in vivo and in vitro (p < 0.05). However, TP-induced elevation of follicle stimulating hormone and luteinizing hormone concentrations, malondialdehyde levels, reactive oxygen species levels, apoptosis rate, mitophagy, and the mRNA and protein expressions of LC3-II/LC3-I, PTEN-induced kinase 1 (PINK1), and Parkin were decreased (p < 0.05). In addition, XJCRTSZW treatment markedly increased cell viability in vitro (p < 0.05). CONCLUSIONS: XJCRTSZW protects TP-induced rats from oxidative stress injury via the mitophagy-mediated PINK1/Parkin pathway.

Insights into taxadiene synthase catalysis and promiscuity facilitated by mutability landscape and molecular dynamics.

MAIN CONCLUSION: Protein modeling, carbocation docking, and molecular dynamics along with structure-based mutability landscapes provided insight into taxadiene synthase catalysis (first step of the anticancer Taxol biosynthesis), protein structure-function correlations, and promiscuity. Plant terpenes belong to one of the largest and most diverse classes of natural products. This diversity is driven by the terpene synthase enzyme family which comprises numerous different synthases, several of which are promiscuous. Taxadiene synthase (TXS) is a class I diterpene synthase that catalyzes the first step in the biosynthesis pathway of the diterpene Taxol, an anticancer natural product produced by the Taxus plant. Exploring the molecular basis of TXS catalysis and its promiscuous potential garnered interest as a necessary means for understanding enzyme evolution and engineering possibilities to improve Taxol biosynthesis. A catalytically active closed conformation TXS model was designed using the artificial intelligence system, AlphaFold, accompanied by docking and molecular dynamics simulations. In addition, a mutability landscape of TXS including 14 residues was created to probe for structure-function relations. The mutability landscape revealed no mutants with improved catalytic activity compared to wild-type TXS. However, mutations of residues V584, Q609, V610, and Y688 showed high degree of promiscuity producing cembranoid-type and/or verticillene-type major products instead of taxanes. Mechanistic insights into V610F, V584M, Q609A, and Y688C mutants compared to the wild type revealed the trigger(s) for product profile change. Several mutants spanning residues V584, Q609, Y688, Y762, Q770, and F834 increased production of taxa-4(20),11(12)-diene which is a more favorable substrate for Taxol production compared to taxa-4(5),11(12)-diene. Finally, molecular dynamics simulations of the TXS reaction cascade revealed residues involved in ionization, carbocation stabilization, and cyclization ushering deeper understanding of the enzyme catalysis mechanism.

Total Syntheses of Phorbol and 11 Tigliane Diterpenoids and Their Evaluation as HIV Latency-Reversing Agents.

Tigliane diterpenoids possess exceptionally complex structures comprising common 5/7/6/3-membered ABCD-rings and disparate oxygen functionalities. While tiglianes display a wide range of biological activities, compounds with HIV latency-reversing activity can eliminate viral reservoirs, thereby serving as promising leads for new anti-HIV agents. Herein, we report collective total syntheses of phorbol (13) and 11 tiglianes 14-24 with various acylation patterns and oxidation states, and their evaluation as HIV latency-reversing agents. The syntheses were strategically divided into five stages to increase the structural complexity. First, our previously established sequence enabled the expeditious preparation of ABC-tricycle 9 in 15 steps. Second, hydroxylation of 9 and ring-contractive D-ring formation furnished phorbol (13). Third, site-selective attachment of two acyl groups to 13 produced four phorbol diesters 14-17. Fourth, the oxygen functionalities were regio- and stereoselectively installed to yield five tiglianes 18-22. Fifth, further oxidation to the most densely oxygenated acerifolin A (23) and tigilanol tiglate (24) was realized through organizing a 3D shape of the B-ring. Assessment of the HIV latency-reversing activities of the 12 tiglianes revealed seven tiglianes (14-17 and 22-24) with 20- to 300-fold improved efficacy compared with prostratin (12), a representative latency-reversing agent. Therefore, the robust synthetic routes to a variety of tiglianes with promising activities devised in this study provide opportunities for advancing HIV eradication strategies.

[Triptolide reduces neuronal damage in cerebral ischemia-reperfusion rats by promoting microglial M2 polarization].

Objective To investigate the effects of triptolide (TP) on microglial M1/M2 polarization after cerebral ischemia-reperfusion (I/R) injury in rats and the underlying molecular mechanism. Methods A rat model of middle cerebral artery occlusion (MCAO) was established. TP was administered to rats at doses of 0.1 and 0.2 mg/kg, with a sham surgery group as the control group. Longa scoring was performed to grade neurological deficits in rats; HE staining was used to observe the morphology of neurons in ischemic brain tissues; neuron-specific nuclear protein (NeuN) immunofluorescence staining was used to measure the number of neurons; and Western blot analysis was used to measure the expression levels of ionised calcium-binding adaptor molecule-1 (Iba1), inducible nitric oxide synthase (iNOS), arginase 1 (Arg1), Toll-like receptor 4 (TLR4), nuclear factor κB (NF-κB), NeuN and caspase-3 in ischemic-brain tissues. The protein levels of interleukin 1ß (IL-1ß) and IL-10 were measured by ELISA. Immunofluorescence double labelling was performed to detect the expression of Arg1 and TLR4 in microglia. Results Compared with the model group, the neurological score of the TP treatment group was significantly reduced and the neuronal damage was significantly alleviated. IL-1ß levels decreased while IL-10 levels increased. The expression levels of iNOS, TLR4, NF-κB and caspase-3 decreased, while the expression levels of Arg1 and NeuN increased. Conclusion TP treatment ameliorates cerebral I/R injury in rats, which may be attributed to the promotion of microglial M2 polarization, thereby reducing the release of inflammatory factors and inhibiting apoptosis.

Biochemical characterization of a multiple prenyltransferase from Tolypocladium inflatum.

Prenylation plays a pivotal role in the diversification and biological activities of natural products. This study presents the functional characterization of TolF, a multiple prenyltransferase from Tolypocladium inflatum. The heterologous expression of tolF in Aspergillus oryzae, coupled with feeding the transformed strain with paxilline, resulted in the production of 20- and 22-prenylpaxilline. Additionally, TolF demonstrated the ability to prenylated the reduced form of paxilline, ß-paxitriol. A related prenyltransferase TerF from Chaunopycnis alba, exhibited similar substrate tolerance and regioselectivity. In vitro enzyme assays using purified recombinant enzymes TolF and TerF confirmed their capacity to catalyze prenylation of paxilline, ß-paxitriol, and terpendole I. Based on previous reports, terpendole I should be considered a native substrate. This work not only enhances our understanding of the molecular basis and product diversity of prenylation reactions in indole diterpene biosynthesis, but also provides insights into the potential of fungal indole diterpene prenyltransferase to alter their position specificities for prenylation. This could be applicable for the synthesis of industrially useful compounds, including bioactive compounds, thereby opening up new avenues for the development of novel biosynthetic strategies and pharmaceuticals. KEY POINTS: • The study characterizes TolF as a multiple prenyltransferase from Tolypocladium inflatum. • TerF from Chaunopycnis alba shows similar substrate tolerance and regioselectivity compared to TolF. • The research offers insights into the potential applications of fungal indole diterpene prenyltransferases.

Exploration of Cytochrome P450-Related Interactions between Aflatoxin B1 and Tiamulin in Broiler Chickens.

Poultry may face simultaneous exposure to aflatoxin B1 (AFB1) and tiamulin (TIA), given mycotoxin contamination and antibiotic use. As both mycotoxins and antibiotics can affect cytochrome P450 enzymes (CYP450), our study aimed to explore their interaction. We developed UHPLC-MS/MS methods for the first-time determination of the interaction between TIA and AFB1 in vitro and in vivo in broiler chickens. The inhibition assay showed the half maximal inhibitory concentration (IC50) values of AFB1 and TIA in chicken liver microsomes are more than 7.6 µM, indicating an extremely weak inhibitory effect on hepatic enzymes. Nevertheless, the oral TIA pharmacokinetic results indicated that AFB1 significantly increased the area under the plasma concentration-time curve (AUClast) of TIA by 167% (p < 0.01). Additionally, the oral AFB1 pharmacokinetics revealed that TIA increased the AUClast and mean residence time (MRT) of AFB1 by 194% (p < 0.01) and 136%, respectively. These results suggested that the observed inhibition may be influenced by other factors, such as transport. Therefore, it is meaningful to further explore transport and other enzymes, involved in the interaction between AFB1 and TIA. Furthermore, additional clinical studies are necessary to thoroughly assess the safety of co-exposure with mycotoxins and antibiotics.