Total synthesis/semi-synthesis of natural isopentenyl flavonoids with inhibitory activity on NLRP3 inflammasome.

Inflammation is the body's defense response to stimuli. When the homeostatic balance is disturbed, disease may result. Flavonoids have clear anti-inflammatory effects and the isopentenyl group significantly enhances the pharmacological activity of flavonoids. Therefore, isopentenyl flavonoids have the potential to serve as lead compounds for the development of anti-inflammatory drugs. Throughout this research, eight natural compounds were synthesized, including 5,7-dihydroxy-4'-methoxy-8-prenylflavonoid (1), 4'-O-Methylatalantoflavone (2), Kushenol W (3) and Racemoflavone (5), which were totally synthesized for the first time. Additionally, three flavonols: Licoflavonol (6), 3,5,7,3',4'-pentahydroxy-6-prenylflavonol (7) and Macarangin (8), can be one-step synthesized by direct C-isopentenylation. In the process, an economical and efficient C-isopentenylation method was also simultaneously explored that could facilitate the efficient synthesis of natural products. These compounds were evaluated for their potential anti-inflammatory activities via the NLRP3 signaling pathway. Notably, Macarangin (8) manifested the most potent inhibitory effect. The SAR (Structure-Activity Relationships) also showed the introduction of the isopentenyl group was determined to enhance these effects, whereas simple flavonoid frameworks or cyclization of isopentenyl groups all diminished anti-inflammatory activity.

Crystal Structure Determination of Nucleotide-sugar Binding Domain of Human UDP-glucuronosyltransferases 2B10.

BACKGROUND: UDP-glucuronosyltransferases (UGTs) play a crucial role in maintaining endobiotic homeostasis and metabolizing xenobiotic compounds, particularly clinical drugs. However, the detailed catalytic mechanism of UGTs has not been fully elucidated due to the limited availability of reliable protein structures. Determining the catalytic domain of human UGTs has proven to be a significant challenge, primarily due to the difficulty in purifying and crystallizing the full-length protein. OBJECTIVES: This study focused on the human UGT2B10 C-terminal cofactor binding domain, aiming to provide structural insights into the fundamental catalytic mechanisms. METHODS: In this study, the C-terminal sugar-donor binding domain of human UGT2B10 was purified and crystallized using the vapor-diffusion method. The resulting UGT2B10 CTD crystals displayed high-quality diffraction patterns, allowing for data collection at an impressive resolution of 1.53 Å using synchrotron radiation. Subsequently, the structure of the UGT2B10 CTD was determined using the molecule replacement method with a homologous structure. RESULTS: The crystals were monoclinic, belonging to the space C2 with unit-cell parameters a = 85.90 Å, b = 58.39 Å, c = 68.87 Å, α = γ = 90°, and ß = 98.138°. The Matthews coefficient VM was determined to be 2.24 Å3 Da-1 (solvent content 46.43%) with two molecules in the asymmetric unit. CONCLUSION: The crystal structure of UGT2B10 CTD was solved at a high resolution of 1.53 Å, revealing a conserved cofactor binding pocket. This is the first study determining the C-terminal cofactor binding domain of human UGT2B10, which plays a key role in additive drug metabolism.

Synthesis-accessibility-oriented design of c-Jun N-terminal kinase 1 inhibitor.

Idiopathic pulmonary fibrosis (IPF) is a severe and progressive lung disease with poor prognosis and limited treatment options. The c-Jun N-Terminal Kinase 1 (JNK1), a key component of the MAPK pathway, has been implicated in the pathogenesis of IPF and represents a potential therapeutic target. However, the development of JNK1 inhibitors has been slowed, partly due to synthetic complexity in medicinal chemistry modification. Here, we report a synthesis-accessibility-oriented strategy for designing JNK1 inhibitors based on computational prediction of synthetic feasibility and fragment-based molecule generation. This strategy led to the discovery of several potent JNK1 inhibitors, such as compound C6 (IC50 = 33.5 nM), which exhibited comparable activity to the clinical candidate CC-90001 (IC50 = 24.4 nM). The anti-fibrotic effect of C6 was further confirmed in animal model of pulmonary fibrosis. Moreover, compound C6 could be synthesized in only two steps, compared to nine steps for CC-90001. Our findings suggest that compound C6 is a promising lead for further optimization and development as a novel anti-fibrotic agent targeting JNK1. In addition, the discovery of C6 also demonstrates the feasibility of synthesis-accessibility-oriented strategy in lead discovery.

Kinetic characterization of an efficient cocaine hydrolase against toxic metabolites of cocaine.

In the presence of alcohol, cocaine metabolism produces a number of metabolites, including three toxic ones (cocaethylene, norcocaine, and norcocaethylene) which are all more toxic than cocaine itself, with the toxicity in the order of cocaine < cocaethylene < norcocaine < norcocaethylene. In this study, we performed kinetic analysis on our previously reported cocaine hydrolase (E30-6) for its catalytic activities accelerating the hydrolysis of the three toxic metabolites in comparison with cocaine. Based on the obtained kinetic data, the in vitro catalytic efficiencies of the enzyme against these substrates are in the order of cocaine > cocaethylene > norcocaine > norcocaethylene. It has been demonstrated that E30-6 can efficiently accelerate the hydrolysis of not only cocaine itself, but also all three toxic metabolites in vitro and in vivo. E30-6 is the most efficient enzyme for each of these toxic substrates (cocaine, cocaethylene, norcocaine, and norcocaethylene) among all the reported enzymes as far as we know at this point. These findings suggest that E30-6 is capable of efficiently treating cocaine toxicity even when alcohol and cocaine are used concurrently.

Development of a Highly Efficient Long-Acting Cocaine Hydrolase Entity to Accelerate Cocaine Metabolism.

It is particularly challenging to develop a truly effective pharmacotherapy for cocaine use disorder (CUD) treatment. Accelerating cocaine metabolism via hydrolysis at cocaine benzoyl ester using an efficient cocaine hydrolase (CocH) is known as a promising pharmacotherapeutic approach to CUD treatment. Preclinical and clinical studies on our first CocH (CocH1), in its human serum albumin-fused form known as TV-1380, have demonstrated the promise of a general concept of CocH-based pharmacotherapy for CUD treatment. However, the biological half-life of TV-1380 (t1/2 = 8 h in rats, associated with t1/2 = 43-77 h in humans) is not long enough for practical treatment of cocaine dependence, which requires enzyme injection for no more than once weekly. Through protein fusion of a human butyrylcholinesterase mutant (denoted as CocH5) with a mutant (denoted as Fc(M6)) of Fc from human IgG1, we have designed, prepared, and tested a new fusion protein (denoted as CocH5-Fc(M6)) for its pharmacokinetic profile and in vivo catalytic activity against (-)-cocaine. CocH5-Fc(M6) represents the currently most efficient long-acting cocaine hydrolase with both the highest catalytic activity against (-)-cocaine and the longest elimination half-life (t1/2 = 229 ± 5 h) in rats. As a result, even at a single modest dose of 3 mg/kg, CocH5-Fc(M6) can significantly and effectively accelerate the metabolism of cocaine in rats for at least 60 days. In addition, ∼70 nM CocH5-Fc(M6) in plasma was able to completely block the toxicity and physiological effects induced by intraperitoneal injection of a lethal dose of cocaine (60 mg/kg).

Role of Histone Post-Translational Modifications in Inflammatory Diseases.

Inflammation is a defensive reaction for external stimuli to the human body and generally accompanied by immune responses, which is associated with multiple diseases such as atherosclerosis, type 2 diabetes, Alzheimer's disease, psoriasis, asthma, chronic lung diseases, inflammatory bowel disease, and multiple virus-associated diseases. Epigenetic mechanisms have been demonstrated to play a key role in the regulation of inflammation. Common epigenetic regulations are DNA methylation, histone modifications, and non-coding RNA expression; among these, histone modifications embrace various post-modifications including acetylation, methylation, phosphorylation, ubiquitination, and ADP ribosylation. This review focuses on the significant role of histone modifications in the progression of inflammatory diseases, providing the potential target for clinical therapy of inflammation-associated diseases.

The protonation state of Glu202 in acetylcholinesterase.

Acetylcholinesterase (AChE) is the crucial enzyme in the central nervous system. It is the target of various organophosphorus nerve agents and pesticides, and the inhibition of AChE is a therapeutic strategy for the treatment of various neurological-related diseases. The Glu202 is a key residue adjacent to the catalytic His447 and plays important role in catalysis. Although the Glu202 has long been considered as negatively charged in many studies, more and more evidences support a protonated Glu202. However, Glu202 is freely accessible by solvent, and thus it seems more reasonable for Glu202 to majorly take the deprotonated state. In the present work, we carried out a series of molecular dynamics simulations with the Glu202 adopting different protonation states. Our results show that the protonated Glu202 is important in maintaining the key hydrogen bond network that supports the catalytic triad, whereas the deprotonated Glu202 results in the collapse of the key hydrogen bond network which consequently destabilizes the catalytic His447. We also notice that different protonation states of Glu202 merely alters the binding mode of ACh. However, since the catalytic His447 is disrupted if Glu202 is deprotonated, His447 cannot facilitate the nucleophilic attack performed by Ser203. Therefore, the catalytic efficiency of ACh hydrolysis should be remarkably decreased if Glu202 is deprotonated. Our findings suggest that, when designing and developing highly active AChE inhibitors or proposing mechanistic hypotheses for AChE-catalyzed reactions, the protonated state of Glu202 should be considered.

Terragines F-G produced by endophytic Bacillus sp. SH-1.2-ROOT-18 from Dendrobium officinale.

Two new terragine analogs (1‒2) with special succinimide and aminopentane moieties were isolated from the fermentation broth of Bacillus sp. SH-1.2-ROOT-18, an endophyte previously discovered from the root of Dendrobium officinale. The structures were elucidated base on comprehensive 1 D/2D NMR and MS data analysis. Complete NMR assignments for the first reported naturally occurring metabolite 3 was also provided.[Formula: see text].

Precision 3D printed meniscus scaffolds to facilitate hMSCs proliferation and chondrogenic differentiation for tissue regeneration.

BACKGROUND: The poor regenerative capability and structural complexity make the reconstruction of meniscus particularly challenging in clinic. 3D printing of polymer scaffolds holds the promise of precisely constructing complex tissue architecture, however the resultant scaffolds usually lack of sufficient bioactivity to effectively generate new tissue. RESULTS: Herein, 3D printing-based strategy via the cryo-printing technology was employed to fabricate customized polyurethane (PU) porous scaffolds that mimic native meniscus. In order to enhance scaffold bioactivity for human mesenchymal stem cells (hMSCs) culture, scaffold surface modification through the physical absorption of collagen I and fibronectin (FN) were investigated by cell live/dead staining and cell viability assays. The results indicated that coating with fibronectin outperformed coating with collagen I in promoting multiple-aspect stem cell functions, and fibronectin favors long-term culture required for chondrogenesis on scaffolds. In situ chondrogenic differentiation of hMSCs resulted in a time-dependent upregulation of SOX9 and extracellular matrix (ECM) assessed by qRT-PCR analysis, and enhanced deposition of collagen II and aggrecan confirmed by immunostaining and western blot analysis. Gene expression data also revealed 3D porous scaffolds coupled with surface functionalization greatly facilitated chondrogenesis of hMSCs. In addition, the subcutaneous implantation of 3D porous PU scaffolds on SD rats did not induce local inflammation and integrated well with surrounding tissues, suggesting good in vivo biocompatibility. CONCLUSIONS: Overall, this study presents an approach to fabricate biocompatible meniscus constructs that not only recapitulate the architecture and mechanical property of native meniscus, but also have desired bioactivity for hMSCs culture and cartilage regeneration. The generated 3D meniscus-mimicking scaffolds incorporated with hMSCs offer great promise in tissue engineering strategies for meniscus regeneration.

Cytotoxic Guaianolide Sesquiterpenoids from Ainsliaea fragrans.

Twelve guaianolide-type sesquiterpene oligomers with diverse structures were isolated from the whole plants of Ainsliaea fragrans, including a novel trimer (1) and two new dimers (2, 3). The chemical structures of the new compounds were elucidated through spectroscopic data interpretation and computational calculations. Ainsfragolide (1) is an unusual guaianolide sesquiterpene trimer generated with a novel C-C linkage at C2'-C15″, which may be biosynthesized prospectively through a further Michael addition. Cytotoxicity results showed that ainsfragolide (1) was the most potent compound against five cancer cell lines with IC50 values in the range of 0.4-8.3 µM.

Computational Design and Crystal Structure of a Highly Efficient Benzoylecgonine Hydrolase.

Benzoylecgonine (BZE) is the major toxic metabolite of cocaine and is responsible for the long-term cocaine-induced toxicity owing to its long residence time in humans. BZE is also the main contaminant following cocaine consumption. Here, we identified the bacterial cocaine esterase (CocE) as a BZE-metabolizing enzyme (BZEase), which can degrade BZE into biological inactive metabolites (ecgonine and benzoic acid). CocE was redesigned by a reactant-state-based enzyme design theory. An encouraging mutant denoted as BZEase2, presented a >400-fold improved catalytic efficiency against BZE compared with wild-type (WT) CocE. In vivo, a single dose of BZEase2 (1 mg kg-1 , IV) could eliminate nearly all BZE within only two minutes, suggesting the enzyme has the potential for cocaine overdose treatment and BZE elimination in the environment by accelerating BZE clearance. The crystal structure of a designed BZEase was also determined.

Transcriptome sequencing and functional characterization of new sesquiterpene synthases from Curcuma wenyujin.

Tubers of Curcuma wenyujin are rich in essential oils, mainly various sesquiterpenes, showing antibacterial, anti-viral and anti-tumor effects. However, the molecular mechanism of C. wenyujin is deficient and related sesquiterpene synthases are still unclear. In this study, the transcriptome data of tubers and leaves from C. wenyujin were obtained and assembled into 78 092 unigenes. Of them, 244 unigenes were predicted to be involved in terpenoid biosynthesis while 131 unigenes were categorized as the "Terpenoid backbone biosynthesis" (TBB) term. Twenty-two unigenes possessed terpene synthase domain; five were predicted to be sesquiterpene synthases. Of the 208 unigenes annotated as cytochromes P450, 8 unigenes with full-length coding sequences were part of the CYP71 clade that primarily may perform hydroxylations of specialized metabolites. Furthermore, Ten DEGs related to the C5 precursor supply and sesquiterpene synthesis were validated by Real-time PCR; that showed a close correspondence with transcriptome sequence. A novel germacrene B synthase (CwGBS) and α-santalene synthase (CwSS) were identified in metabolically engineering E. coli. This study provided the first de novo transcriptome comparative analysis of leaf and tuber tissues from C. wenyujin, aiming to understand genetic mechanisms. Key genes involved in the biosynthesis of sesquiterpene will help for revealing the underlying mechanisms of C. wenyujin.

Sub-lethal toxicity and elimination of the cocaine metabolite, benzoylecgonine: a narrative review.

Cocaine abuse is a serious global public health and social problem, and cocaine detoxification remains a challenge. Benzoylecgonine (BE) is the main toxic metabolite after cocaine consumption, with a longer retention time in the body and environment than cocaine itself. According to many studies, the toxicity of BE to humans is as significant as cocaine itself. Moreover, BE is recognized as an addictive drug contaminant in the environment, especially the freshwater system, leading to worries of its ecotoxicity. Extensive studies on the adverse effects of BE on both humans and ecology have been conducted, showing a marked sub-lethal toxicity of BE to diverse organisms. To eliminate BE in vivo and in vitro, various elimination methods have been developed and their BE removal capacity were evaluated. In this review, we aimed to summarize information in the literature to understand better BE toxicity and elimination that may facilitate the clinical treatment of cocaine abuse. By studying the critical role of BE in cocaine abuse, we propose that the ideal treatment for cocaine abuse should not only detoxify cocaine itself but also remove or degrade BE. Emphasizing the necessity of developing effective BE elimination methods is significant for the development of potential clinical treatments and environmental protections.

Huoshanmycins A‒C, New Polyketide Dimers Produced by Endophytic Streptomyces sp. HS-3-L-1 From Dendrobium huoshanense.

Three new polyketide dimers named huoshanmycins A‒C (1-3) were isolated from a plant endophytic Streptomyces sp. HS-3-L-1 in the leaf of Dendrobium huoshanense, which was collected from the Cultivation base in Jiuxianzun Huoshanshihu Co., Ltd. The dimeric structures of huoshanmycins were composed of unusual polyketides SEK43, SEK15, or UWM4, with a unique methylene linkage. Their structures were elucidated through comprehensive 1D-/2D-NMR and HRESIMS spectroscopic data analysis. The cytotoxicity against MV4-11 human leukemia cell by the Cell Counting Kit-8 (CCK8) method was evaluated using isolated compounds with triptolide as positive control (IC50: 1.1 ± 0.4 µM). Huoshanmycins A and B (1, 2) displayed moderate cytotoxicity with IC50 values of 32.9 ± 7.2 and 33.2 ± 6.1 µM, respectively.

Stable and efficient immobilization of bi-enzymatic NADPH cofactor recycling system under consecutive microwave irradiation.

One of the challenges in biocatalysis is the development of stable and efficient bi-enzymatic cascades for bio-redox reactions coupled to the recycling of soluble cofactors. Aldo-keto reductase (LEK) and glucose dehydrogenase (GDH) can be utilized as the NADPH recycling system for economic and efficient biocatalysis of (R)-4-chloro-3-hydroxybutanoate ((R)-CHBE), an important chiral pharmaceutical intermediate. The LEK and GDH was efficiently co-immobilized in mesocellular siliceous foams (MCFs) under microwave irradiation (CoLG-MIA). while they were also co-immobilized by entrapment in calcium alginate without MIA as control (CoLG-CA). The relative activity of CoLG-MIA was increased to 140% compared with that of free LEK. The CoLG-MIA exhibited a wider range of pH and temperature stabilities compared with other preparations. The thermal, storage and batch operational stabilities of microwave-assisted immobilized LEK-GDH were also improved. The NADPH recycling system exhibited the potential as the stable and efficient catalyst for the industrial preparation of (R)-CHBE.

New peptidendrocins and anticancer chartreusin from an endophytic bacterium of Dendrobium officinale.

BACKGROUND: Endophyte has now become a potential source for the discovery of novel natural products, as they participate in biochemical pathways of their hosts and produce analogous or novel bioactive compounds. As an epiphytic plant, Dendrobium officinale is one of precious Chinese medicines with various activities. It is well known for containing diverse endophytes, but so far not much is known about their secondary metabolites. METHODS: the plant tissues were cut and cultured on agar plates to isolate and purify the endophytic bacteria from Dendrobium officinale. Taxonomical identification of strains was performed by 16s rRNA. At the same time, the crude extracts of the strains were tested for antibacterial and cytotoxic activities to screen out one endophyte, Streptomyces sp. SH-1.2-R-15 for further study. After scale-up fermentation, isolation, purification and structure elucidation by using MS, 1D/2D-NMR spectroscopic method, secondary metabolites were identified and submitted for biological activity test. RESULTS: Fifty-eight endophytic strains representing 9 genera were obtained, with 50% of strains were Streptomyces. One of the most active strain, Streptomyces sp. 1.2-R-15, was selected for bioassay-guided isolation, which led to the discovery of two new peptide-type compounds 1 and 2, as well as a bioactive chartreusin, and four other known natural products. Their structures were determined by comprehensive spectroscopic techniques. Chartreusin showed potent cytotoxicity against Hep3B2.1-7 (IC50 =18.19 µM) and H1299 (IC50 =19.74 µM) cancer cell lines, and antibacterial activity against S. aureus (IC50 =23.25 µM). CONCLUSIONS: This study highlights the endophytic bacteria from medical plant D. officinale have potential bioactivity and natural product diversity, thus implicates them as a valuable source for new anticancer and antibiotics agents.

Sustainability of global Golden Inland Waterways.

Sustainable inland waterways should meet the needs of navigation without compromising the health of riverine ecosystems. Here we propose a hierarchical model to describe sustainable development of the Golden Inland Waterways (GIWs) which are characterized by great bearing capacity and transport need. Based on datasets from 66 large rivers (basin area > 100,000 km2) worldwide, we identify 34 GIWs, mostly distributed in Asia, Europe, North America, and South America, typically following a three-stage development path from the initial, through to the developing and on to the developed stage. For most GIWs, the exploitation ratio, defined as the ratio of actual to idealized bearing capacity, should be less than 80% due to ecological considerations. Combined with the indices of regional development, GIWs exploitation, and riverine ecosystem, we reveal the global diversity and evolution of GIWs' sustainability from 2015 to 2050, which highlights the importance of river-specific strategies for waterway exploitation worldwide.

Chartspiroton, a Tetracyclic Spiro-naphthoquinone Derivative from a Medicinal Plant Endophytic Streptomyces.

A novel 6/6/5/6 tetracyclic polyketide named chartspiroton (1) was isolated from a medicinal plant endophytic Streptomyces in Dendrobium officinale. The complete structure assignment with absolute stereochemistry was elucidated through spectroscopic data, computational calculations, and single-crystal X-ray diffraction. Chartspiroton features an unprecedented naphthoquinone derivative spiro-fused with a benzofuran lactone moiety. A plausible polyketide biosynthetic pathway for 1 suggested intriguing oxidative rearrangement steps to form the five-membered lactone ring.

Structure-Based Design and Discovery of a Long-Acting Cocaine Hydrolase Mutant with Improved Binding Affinity to Neonatal Fc Receptor for Treatment of Cocaine Abuse.

Despite decades of efforts to develop a pharmacotherapy for cocaine abuse treatment, there is still no FDA-approved treatment of diseases associated with this commonly abused drug. Our previously designed highly efficient cocaine hydrolases (CocHs) and the corresponding Fc-fusion proteins (e.g., CocH3-Fc) are recognized as potentially promising therapeutic enzyme candidates for cocaine abuse treatment, but all with limited biological half-lives. In order to prolong the biological half-life and, thus, decrease the required frequency of the enzyme administration for cocaine abuse treatment, we have modeled the Fc-fusion CocH binding with neonatal Fc receptor (FcRn) in the present study. This approach led to the design and testing of CocH3-Fc(M6), a CocH3-Fc mutant with nearly 100-fold increased binding affinity: from Kd = ~ 4 µM to Kd = 43 nM. As a result, CocH3-Fc(M6) indeed revealed a markedly prolonged biological half-life (t1/2 = 206 ± 7 h or ~ 9 days) in rats, longer than other known Fc-fusion protein drugs such as abatacept and alefacept (for other therapeutic purposes) in the same species (rats). It has been demonstrated that a single dose of 3 mg/kg CocH3-Fc(M6) effectively blocked 20 mg/kg cocaine-induced hyperactivity on day 18 after CocH3-Fc(M6) administration. This is the first attempt to rationally design long-acting Fc-fusion enzyme mutant based on combined computational modeling and experimental measurement of the Fc-fusion CocH binding with FcRn. The similar structure-based design strategy may be used to prolong the biological half-lives of other Fc-fusion protein drugs.