Chemoenzymatic Synthesis of 2-Aryl Thiazolines from 4-Hydroxybenzaldehydes Using Vanillyl Alcohol Oxidases.

Nitrogen heterocycles are commonly found in bioactive natural products and drugs. However, the biocatalytic tools for nitrogen heterocycle synthesis are limited. Herein, we report the discovery of vanillyl alcohol oxidases (VAOs) as efficient biocatalysts for the one-pot synthesis of 2-aryl thiazolines from various 4-hydroxybenzaldehydes and aminothiols. The wild-type biocatalyst features a broad scope of 4-hydroxybenzaldehydes. Though the scope of aminothiols is limited, it could be improved via semi-rational protein engineering, generating a variant to produce previously inaccessible cysteine-derived bioactive 2-aryl thiazolines using the wild-type VAO. Benefiting from the derivatizable functional groups in the enzymatic products, we further chemically modified these products to expand the chemical space, offering a new chemoenzymatic strategy for the green and efficient synthesis of structurally diverse 2-aryl-thiazoline derivatives to prompt their use in drug discovery and catalysis.

Verteporfin inhibits TGF-ß signaling by disrupting the Smad2/3-Smad4 interaction.

Transforming growth factor-ß (TGF-ß) signaling plays a crucial role in pathogenesis, such as accelerating tissue fibrosis and promoting tumor development at the later stages of tumorigenesis by promoting epithelial-mesenchymal transition (EMT), cancer cell migration, and invasion. Targeting TGF-ß signaling is a promising therapeutic approach, but nonspecific inhibition may result in adverse effects. In this study, we focus on the Smad2/3-Smad4 complex, a key component in TGF-ß signaling transduction, as a potential target for cancer therapy. Through a phase-separated condensate-aided biomolecular interaction system, we identified verteporfin (VP) as a small-molecule inhibitor that specifically targets the Smad2/3-Smad4 interaction. VP effectively disrupted the interaction between Smad2/3 and Smad4 and thereby inhibited canonical TGF-ß signaling, but not the interaction between Smad1 and Smad4 in bone morphogenetic protein (BMP) signaling. Furthermore, VP exhibited inhibitory effects on TGF-ß-induced EMT and cell migration. Our findings indicate a novel approach to develop protein-protein interaction inhibitors of the canonical TGF-ß signaling pathway for treatments of related diseases.

Structural Pharmacology of TRPV4 Antagonists.

The nonselective calcium-permeable Transient Receptor Potential Cation Channel Subfamily V Member4 (TRPV4) channel regulates various physiological activities. Dysfunction of TRPV4 is linked to many severe diseases, including edema, pain, gastrointestinal disorders, lung diseases, and inherited neurodegeneration. Emerging TRPV4 antagonists show potential clinical benefits. However, the molecular mechanisms of TRPV4 antagonism remain poorly understood. Here, cryo-electron microscopy (cryo-EM) structures of human TRPV4 are presented in-complex with two potent antagonists, revealing the detailed binding pockets and regulatory mechanisms of TRPV4 gating. Both antagonists bind to the voltage-sensing-like domain (VSLD) and stabilize the channel in closed states. These two antagonists induce TRPV4 to undergo an apparent fourfold to twofold symmetry transition. Moreover, it is demonstrated that one of the antagonists binds to the VSLD extended pocket, which differs from the canonical VSLD pocket. Complemented with functional and molecular dynamics simulation results, this study provides crucial mechanistic insights into TRPV4 regulation by small-molecule antagonists, which may facilitate future drug discovery targeting TRPV4.

Lumbar puncture increases Alzheimer's disease biomarker levels in cerebrospinal fluid of rhesus monkeys.

Cerebrospinal fluid (CSF) samples are commonly collected via lumbar puncture (LP) in both clinical and research settings for measurement of biomarkers of Alzheimer's disease (AD). To determine the effects of LP on CSF AD biomarkers, we collected CSF samples at seven different time points after an LP in rhesus monkeys. We find that amyloid-beta (Aß) and Tau levels increased significantly on day 1, peaked on day 3, and returned to baseline on day 10 after LP. The NFL levels increased significantly on day 5, peaked on day 10, and returned to baseline after day 30. The increased AD biomarker levels were mainly due to CSF outflow and deep intrathecal invasion during LP. Therefore, if LPs are repeated within a short period of time, prior LP can affect Aß and Tau levels within 10 days and NFL levels within 30 days, which may lead to clinical misdiagnosis or incorrect scientific conclusions.

Enzymatic Degradation of Deoxynivalenol with the Engineered Detoxification Enzyme Fhb7.

In the era of global climate change, the increasingly severe Fusarium head blight (FHB) and deoxynivalenol (DON) contamination have caused economic losses and brought food and feed safety concerns. Recently, an FHB resistance gene Fhb7 coding a glutathione-S transferase (GST) to degrade DON by opening the critical toxic epoxide moiety was identified and opened a new window for wheat breeding and DON detoxification. However, the poor stability of Fhb7 and the elusiveness of the catalytic mechanism hinder its practical application. Herein, we report the first structure of Fhb7 at 2.41 Å and reveal a unique catalytic mechanism of epoxide opening transformation in GST family proteins. Furthermore, variants V29P and M10 showed that 5.5-fold and 266.7-fold longer half-life time than wild-type, respectively, were identified. These variants offer broad substrate scope, and the engineered biosafe Bacillus subtilis overexpressing the variants shows excellent DON degradation performance, exhibiting potential at bacterium engineering to achieve DON detoxification in the feed and biomedicine industry. This work provides a profound mechanistic insight into the enzymatic activities of Fhb7 and paves the way for further utilizing Fhb7-related enzymes in crop breeding and DON detoxification by synthetic biology.

The evolutionary origin of naturally occurring intermolecular Diels-Alderases from Morus alba.

Biosynthetic enzymes evolutionarily gain novel functions, thereby expanding the structural diversity of natural products to the benefit of host organisms. Diels-Alderases (DAs), functionally unique enzymes catalysing [4 + 2] cycloaddition reactions, have received considerable research interest. However, their evolutionary mechanisms remain obscure. Here, we investigate the evolutionary origins of the intermolecular DAs in the biosynthesis of Moraceae plant-derived Diels-Alder-type secondary metabolites. Our findings suggest that these DAs have evolved from an ancestor functioning as a flavin adenine dinucleotide (FAD)-dependent oxidocyclase (OC), which catalyses the oxidative cyclisation reactions of isoprenoid-substituted phenolic compounds. Through crystal structure determination, computational calculations, and site-directed mutagenesis experiments, we identified several critical substitutions, including S348L, A357L, D389E and H418R that alter the substrate-binding mode and enable the OCs to gain intermolecular DA activity during evolution. This work provides mechanistic insights into the evolutionary rationale of DAs and paves the way for mining and engineering new DAs from other protein families.

Life and disease status of patients with Parkinson's disease during and after zero-COVID in China: an online survey.

BACKGROUND: Little is known about the impact of the COVID-19 pandemic on patients with Parkinson's disease (PD) at different stages of the pandemic. This study aims to assess the lives and disease status of PD patients during the zero-COVID policy period and after ending the zero-COVID policy. METHODS: This multicenter cross-sectional study included two online surveys among PD patients in China, from May 30 to June 30 in 2022 and from January 1 to February 28 in 2023, respectively. The survey questionnaires contained four sections: (1) status of COVID-19 infection; (2) impact on motor and non-motor symptoms; (3) impact on daily and social lives; and (4) impact on PD disease management. RESULTS: A total of 1764 PD patients participated in the first online survey, with 200 patients having lockdown experience and 3 being COVID-19-positive (0.17%). In addition, 537 patients participated in the second online survey, with 467 patients having COVID-19 infection (86.96%). (1) During zero-COVID, all of the COVID-19-positive patients had mild symptoms of COVID-19 and no death was reported. After zero-COVID, 83.51% of the COVID-19-positive patients had mild symptoms. The overall death rate and inpatient mortality rate of COVID-19-positive PD patients were 3.21% and 30.00%, respectively. (2) During zero-COVID, 49.43% of PD patients reported worsening of PD-related symptoms (lockdown vs. unlockdown, 60.50% vs. 48.02%, P = 0.0009). After zero-COVID, 54.93% of PD patients reported worsening of PD-related symptoms (COVID-19 positive vs. COVID-19 negative, 59.31% vs. 25.71%, P < 0.0001). (3) During zero-COVID, 62.36% of patients felt worried, and 'limited outdoor activities' (55.39%) was the top reason for mental health problems. After zero-COVID, 59.03% of patients felt worried, with 'poor health' (58.10%) being the top reason. The PD patients tended to change their daily activities from offline to online, and their economic and caregiver burdens increased both during and after zero-COVID. (4) Most PD patients would like to choose online rehabilitation during (69.56%) and after zero-COVID (69.27%). The demand for online medication purchasing also increased during (47.00%) and after zero-COVID (26.63%). CONCLUSIONS: The COVID-19 pandemic aggravated the motor and non-motor symptoms of PD patients either during or after the zero-COVID policy period. The PD patients also experienced prominent mental health problems, changes in daily activities, and increases in economic and caregiver burdens. The COVID-19 pandemic has changed ways of PD management with increasing demands for online medication purchasing and rehabilitation.

Characterization and heterologous reconstitution of Taxus biosynthetic enzymes leading to baccatin III.

Paclitaxel is a well known anticancer compound. Its biosynthesis involves the formation of a highly functionalized diterpenoid core skeleton (baccatin III) and the subsequent assembly of a phenylisoserinoyl side chain. Despite intensive investigation for half a century, the complete biosynthetic pathway of baccatin III remains unknown. In this work, we identified a bifunctional cytochrome P450 enzyme [taxane oxetanase 1 (TOT1)] in Taxus mairei that catalyzes an oxidative rearrangement in paclitaxel oxetane formation, which represents a previously unknown enzyme mechanism for oxetane ring formation. We created a screening strategy based on the taxusin biosynthesis pathway and uncovered the enzyme responsible for the taxane oxidation of the C9 position (T9αH1). Finally, we artificially reconstituted a biosynthetic pathway for the production of baccatin III in tobacco.

Chemoproteomics, A Broad Avenue to Target Deconvolution.

As a vital project of forward chemical genetic research, target deconvolution aims to identify the molecular targets of an active hit compound. Chemoproteomics, either with chemical probe-facilitated target enrichment or probe-free, provides a straightforward and effective approach to profile the target landscape and unravel the mechanisms of action. Canonical methods rely on chemical probes to enable target engagement, enrichment, and identification, whereas click chemistry and photoaffinity labeling techniques improve the efficiency, sensitivity, and spatial accuracy of target recognition. In comparison, recently developed probe-free methods detect protein-ligand interactions without the need to modify the ligand molecule. This review provides a comprehensive overview of different approaches and recent advancements for target identification and highlights the significance of chemoproteomics in investigating biological processes and advancing drug discovery processes.

A TTC19 mutation associated with progressive movement disorders and peripheral neuropathy: Case report and systematic review.

BACKGROUND: Mitochondrial complex III (CIII) deficiency is an autosomal recessive disease characterized by symptoms such as ataxia, cognitive dysfunction, and spastic paraplegia. Multiple genes are associated with complex III defects. Among them, the mutation of TTC19 is a rare subtype. METHODS: We screened a Chinese boy with weakness of limbs and his non-consanguineous parents by whole exome sequencing and targeted sequencing. RESULTS: We report a Chinese boy diagnosed with mitochondrial complex III defect type 2 carrying a homozygous variant (c.719-732del, p.Leu240Serfs*17) of the TTC19 gene. According to the genotype analysis of his family members, this is an autosomal recessive inheritance. We provide his clinical manifestation. CONCLUSIONS: A new type of TTC19 mutation (c.719-732del, p.Leu240Serfs*17) was found, which enriched the TTC19 gene mutation spectrum and provided new data for elucidating the pathogenesis of CIII-deficient diseases.

Disruption of Dopamine Homeostasis Associated with Alteration of Proteins in Synaptic Vesicles: A Putative Central Mechanism of Parkinson's Disease Pathogenesis.

Vestigial dopaminergic cells in PD have selectivity for a sub-class of hypersensitive neurons with the nigrostriatal dopamine (DA) tract. DA is modulated in pre-synaptic nerve terminals to remain stable. To be specific, proteins at DA release sites that have a function of synthesizing and packing DA in cytoplasm, modulating release and reingestion, and changing excitability of neurons, display regional discrepancies that uncover relevancy of the observed sensitivity to neurodegenerative changes. Although the reasons of a majority of PD cases are still indistinct, heredity and environment are known to us to make significant influences. For decades, genetic analysis of PD patients with heredity in family have promoted our comprehension of pathogenesis to a great extent, which reveals correlative mechanisms including oxidative stress, abnormal protein homeostasis and mitochondrial dysfunction. In this review, we review the constitution of presynaptic vesicle related to DA homeostasis and describe the genetic and environmental evidence of presynaptic dysfunction that increase risky possibility of PD concerning intracellular vesicle transmission and their functional outcomes. We summarize alterations in synaptic vesicular proteins with great involvement in the reasons of some DA neurons highly vulnerable to neurodegenerative changes. We generalize different potential targets and therapeutic strategies for different pathogenic mechanisms, providing a reference for further studies of PD treatment in the future. But it remains to be further researched on this recently discovered and converging mechanism of vesicular dynamics and PD, which will provide a more profound comprehension and put up with new therapeutic tactics for PD patients.

Divergent total syntheses of ITHQ-type bis-ß-carboline alkaloids by regio-selective formal aza-[4 + 2] cycloaddition and late-stage C-H functionalization.

We herein report the first total syntheses of several bis-ß-carboline alkaloids, picrasidines G, S, R, and T, and natural product-like derivatives in a divergent manner. Picrasidines G, S, and T feature an indolotetrahydroquinolizinium (ITHQ) skeleton, while picrasidine R possesses a 1,4-diketone linker between two ß-carboline fragments. The synthesis of ITHQ-type bis-ß-carboline alkaloids could be directly achieved by a late-stage regio-selective aza-[4 + 2] cycloaddition of vinyl ß-carboline alkaloids, suggesting that this remarkable aza-[4 + 2] cycloaddition might be involved in the biosynthetic pathway. Computational studies revealed that such aza-[4 + 2] cycloaddition is a stepwise process and explained the unique regioselectivity (ΔΔG = 3.77 kcal mol-1). Moreover, the successful application of iridium-catalyzed C-H borylation on ß-carboline substrates enabled the site-selective C-8 functionalization for efficient synthesis and structural diversification of this family of natural products. Finally, concise synthesis of picrasidine R by the thiazolium-catalyzed Stetter reaction was also accomplished.

Investigation of Peptide Labeling with ortho-Phthalaldehyde and 2-Acylbenzaldehyde.

ortho-Phthalaldehyde (OPA) with high reactivity to the amine group has been widely used to modify proteins. We discovered new modifications of OPA and 2-acylbenzaldehyde and proposed the reaction mechanism. Using isotope labeling mass spectrometry-based experiment, we identified new cross-linking properties of OPA and 2-acylbenzaldehyde. This reactivity revealed that OPA has the potential to probe proximal amino acids in biological systems.

Microbial-host-isozyme analyses reveal microbial DPP4 as a potential antidiabetic target.

A mechanistic understanding of how microbial proteins affect the host could yield deeper insights into gut microbiota-host cross-talk. We developed an enzyme activity-screening platform to investigate how gut microbiota-derived enzymes might influence host physiology. We discovered that dipeptidyl peptidase 4 (DPP4) is expressed by specific bacterial taxa of the microbiota. Microbial DPP4 was able to decrease the active glucagon like peptide-1 (GLP-1) and disrupt glucose metabolism in mice with a leaky gut. Furthermore, the current drugs targeting human DPP4, including sitagliptin, had little effect on microbial DPP4. Using high-throughput screening, we identified daurisoline-d4 (Dau-d4) as a selective microbial DPP4 inhibitor that improves glucose tolerance in diabetic mice.

C-H Glycosylation of Native Carboxylic Acids: Discovery of Antidiabetic SGLT-2 Inhibitors.

C-Glycosides are critical motifs embedded in many bioactive natural products. The inert C-glycosides are privileged structures for developing therapeutic agents owing to their high chemical and metabolic stability. Despite the comprehensive strategies and tactics established in the past few decades, highly efficient C-glycoside syntheses via C-C coupling with excellent regio-, chemo-, and stereoselectivity are still needed. Here, we report the efficient Pd-catalyzed glycosylation of C-H bonds promoted by weak coordination with native carboxylic acids without external directing groups to install various glycals to the structurally diverse aglycon parts. Mechanistic evidence points to the participation of a glycal radical donor in the C-H coupling reaction. The method has been applied to a wide range of substrates (over 60 examples), including many marketed drug molecules. Natural product- or drug-like scaffolds with compelling bioactivities have been constructed using a late-stage diversification strategy. Remarkably, a new potent sodium-glucose cotransporter-2 inhibitor with antidiabetic potential has been discovered, and the pharmacokinetic/pharmacodynamic profiles of drug molecules have been changed using our C-H glycosylation approach. The method developed here provides a powerful tool for efficiently synthesizing C-glycosides to facilitate drug discovery.

Conformational Dynamics of the Activated GLP-1 Receptor-Gs Complex Revealed by Cross-Linking Mass Spectrometry and Integrative Structure Modeling.

Despite advances in characterizing the structures and functions of G protein-coupled receptors (GPCRs), our understanding of GPCR activation and signaling is still limited by the lack of information on conformational dynamics. It is particularly challenging to study the dynamics of GPCR complexes with their signaling partners because of their transient nature and low stability. Here, by combining cross-linking mass spectrometry (CLMS) with integrative structure modeling, we map the conformational ensemble of an activated GPCR-G protein complex at near-atomic resolution. The integrative structures describe heterogeneous conformations for a high number of potential alternative active states of the GLP-1 receptor-Gs complex. These structures show marked differences from the previously determined cryo-EM structure, especially at the receptor-Gs interface and in the interior of the Gs heterotrimer. Alanine-scanning mutagenesis coupled with pharmacological assays validates the functional significance of 24 interface residue contacts only observed in the integrative structures, yet absent in the cryo-EM structure. Through the integration of spatial connectivity data from CLMS with structure modeling, our study provides a new approach that is generalizable to characterizing the conformational dynamics of GPCR signaling complexes.

Total Synthesis of Diverse Tetramic Acid Bearing cis-Decalin Natural Products.

We report herein the first total syntheses of four natural antibiotics, vermisporin, PF1052/AB4015-A, AB4015-L, AB4015-B, and one hydrogenated natural product derivative, AB4015-A2, that all feature a tetramic acid bearing cis-decalin ring. The construction of the functionalized cis-decalin ring was achieved by a diastereoselective intramolecular Diels-Alder (IMDA) reaction, which proceeded via a rare endo-boat transition state. Through an intramolecular neighboring-group-oriented strategy, the sterically hindered epoxy group in vermisporin, PF1052/AB4015-A and AB4015-L was installed efficiently. A one-pot aminolysis/Dieckmann condensation cascade using l-amino acid derivatives afforded the desired tetramic acid structure. The total synthesis led to the unambiguous verification of the absolute configuration of these natural products.

Risk factors of social anxiety in patients with essential tremor.

Objective: To study the risk factors of social anxiety (SA) in essential tremor (ET) patients. Methods: Motor, cognition, and SA were evaluated using the Fahn-Tolosa-Marin Tremor Rating Scale (FTMTRS), Mini-Mental State Examination (MMSE), and Liebowitz Social Anxiety Scale (LSAS) for each subject. The potential risk factors of SA in ET were analyzed using univariate analysis. Results: A total of 80 ET patients and 85 healthy controls completed the evaluation. The LSAS evaluation showed that the prevalence of SA in the ET group was 48.8%, higher than that in controls (12.9%, P < 0.001). Female (OR = 4.959, P = 0.014), younger age (OR = 4.172, P = 0.037), and head tremor (OR = 4.707, P = 0.025) were risk factors of SA among ET patients. Conclusion: SA is prevalent in patients with ET. Risk factors, such as female sex, age, and head tremor, should be considered for the prevention and intervention of SA in ET patients.

Generation of a human iPSC line (CIBi013-A) from a patient with young-onset Parkinson's disease carrying a novel homozygous PARK7 (DJ-1) mutation.

Mutations in PARK7 and the resulting alterations in its production protein (DJ-1) are tightly associated with Parkinson's disease. We generated a human induced pluripotent stem cell (iPSC) line (CIBi013-A) from a patient with young-onset Parkinson's disease (YOPD) who carried a novel homozygous PARK7 (DJ-1) mutation (chr1:8037723, c.334C>G). The generated iPSCs will be used for investigating phenotype and underlying molecular mechanisms in patient-derived cells.