Fraxin Ameliorates Ulcerative Colitis by Modulating Oxidative Stress, Inflammation and TLR4/NF-κB and MAPK Signaling Pathways.

Objective: UC is a chronic gastrointestinal disorder of uncertain etiology. However, effective therapeutic drug options for UC are relatively limited. Fraxin represents a principal active constituent within the traditional Chinese medicinal herb known as Cortex Fraxini or Qinpi. Nevertheless, the impact of Fraxin on UC remains uncharted. This study aims to explore the potential of Fraxin, a key component of Cortex Fraxini, in inhibiting DSS-induced intestinal inflammation in mice and to unravel the underlying mechanisms. Methods: In vitro experiment,the RAW264. 7 cells were induced by LPS as the model.In vivo experiment,the mice were induced by DSS as the animal model for a ten day experiment.The ELISA, western blots, measurement of oxidative stress markers and other relevant methods were used to discuss the effect of Fraxin on LPS-induced RAW264.7 cells and the inhibitory effect of Fraxin on intestinal inflammation induced by DSS in mice and underlying mechanisms. Results: Our findings indicated that Fraxin significantly reduced symptoms of UC, such as body weight loss, colonic length shortening, and histological damage. At the molecular level, it inhibited ROS generation, reduced pro-inflammatory cytokines, and regulated key pathways including TLR4/NF-κB and MAPK.The findings indicated that Fraxin diminished the expression of p-NF-κB and p-IκB, downregulated iNOS and COX-2 expression, and lessened p38, JNK and ERK phosphorylation. Conclusion: Taken together, Fraxin ameliorates UC by regulating oxidative stress, inflammation, and TLR4/NF-κB and MAPK pathways, and Fraxin may be a new treatment for UC. Our findings suggest that Fraxin could offer a novel therapeutic approach for UC, targeting oxidative stress and key inflammatory pathways.

LcSAO1, an Unconventional DOXB Clade 2OGD Enzyme from Ligusticum chuanxiong Catalyzes the Biosynthesis of Plant-Derived Natural Medicine Butylphthalide.

Butylphthalide, a prescription medicine recognized for its efficacy in treating ischemic strokes approved by the State Food and Drug Administration of China in 2005, is sourced from the traditional botanical remedy Ligusticum chuanxiong. While chemical synthesis offers a viable route, limitations in the production of isomeric variants with compromised bioactivity necessitate alternative strategies. Addressing this issue, biosynthesis offers a promising solution. However, the intricate in vivo pathway for butylphthalide biosynthesis remains elusive. In this study, we examined the distribution of butylphthalide across various tissues of L. chuanxiong and found a significant accumulation in the rhizome. By searching transcriptome data from different tissues of L. chuanxiong, we identified four rhizome-specific genes annotated as 2-oxoglutarate-dependent dioxygenase (2-OGDs) that emerged as promising candidates involved in butylphthalide biosynthesis. Among them, LcSAO1 demonstrates the ability to catalyze the desaturation of senkyunolide A at the C-4 and C-5 positions, yielding the production of butylphthalide. Experimental validation through transient expression assays in Nicotiana benthamiana corroborates this transformative enzymatic activity. Notably, phylogenetic analysis of LcSAO1 revealed that it belongs to the DOXB clade, which typically encompasses genes with hydroxylation activity, rather than desaturation. Further structure modelling and site-directed mutagenesis highlighted the critical roles of three amino acid residues, T98, S176, and T178, in substrate binding and enzyme activity. By unraveling the intricacies of the senkyunolide A desaturase, the penultimate step in the butylphthalide biosynthesis cascade, our findings illuminate novel avenues for advancing synthetic biology research in the realm of medicinal natural products.

Structure and function of an intermediate GPCR-Gαßγ complex.

Unraveling the signaling roles of intermediate complexes is pivotal for G protein-coupled receptor (GPCR) drug development. Despite hundreds of GPCR-Gαßγ structures, these snapshots primarily capture the fully activated end-state complex. Consequently, a comprehensive understanding of the conformational transitions during GPCR activation and the roles of intermediate GPCR-G protein complexes in signaling remain elusive. Guided by a conformational landscape profiled by 19 F quantitative NMR ( 19 F-qNMR) and Molecular Dynamics (MD) simulations, we resolved the structure of an unliganded GPCR-G protein intermediate complex by blocking its transition to the fully activated end-state complex. More importantly, we presented direct evidence that the intermediate GPCR-Gαsßγ complex initiates a rate-limited nucleotide exchange without progressing to the fully activated end-state complex, thereby bridging a significant gap in our understanding the complexity of GPCR signaling. Understanding the roles of individual conformational states and their complexes in signaling efficacy and bias will help us to design drugs that discriminately target a disease-related conformation.

Consistent Individual Differences Drive Collective Movements in a Tibetan Macaque Group.

Collective movement has emerged as a key area of interest in animal behavior. While individual differences are often viewed as a potential threat to group cohesion, growing evidence suggests that these differences can actually influence an animal's behavior as an initiator or follower during collective movements, thereby driving the group's movement and decision-making processes. To resolve the divergence, we asked how personality can affect the dynamics of collective movements in one group of free-ranging Tibetan macaques (Macaca thibetana) in Huangshan, China. We assessed individual personality using principal component analysis and applied the generalized linear mixed model and linear mixed model to examine the influence of personality on decision making during collective movements. Our findings reveled three distinct personality types among Tibetan macaques: sociability, boldness, and anxiousness. Individuals with higher sociability scores and rank, or those with lower anxiousness scores, were more likely to initiate successful collective movements. Older individuals were less successful in initiating movements compared to young adults. Leaders with lower anxiousness scores or higher rank attracted more followers, with females attracting larger groups than males. As for followers, individuals with higher rank tended to join the collective movement earlier. Additionally, individuals with higher sociability or boldness scores had shorter joining latency in collective movement. Finally, there was a longer joining latency for middle-aged adults compared to young adults. These results suggest that individual differences are a potential driver of collective movements. We provide some insights into the relationships between personality and decision making in Tibetan macaques.

Social risk to infant: The role of kin for maternal visual monitoring in Tibetan macaques.

Maternal monitoring of conspecifics is a crucial anti-predator strategy that also protects infants against risks within the social group. This study examines how maternal characteristics, infant characteristics, mother-infant distance, and the social environment affect maternal monitoring behaviors in free-ranging Tibetan macaques (Macaca thibetana). We observed 12 females with infants and analyzed their visual monitoring patterns. Our findings indicate that maternal rank significantly influences the time allocated to maternal visual monitoring, higher-ranking mothers spending less time than lower-ranking mothers. Maternal experience also played a role in monitoring strategies. Differences in monitoring strategies were observed based on maternal experience: first-time mothers (primiparity) engaged in longer but less frequent monitoring sessions compared to experienced mothers (multiparity). The time and frequency of maternal monitoring decreased as infants aged, and mothers with male infants showed higher levels of monitoring than those with female infants. The distance between mother and infant also affected visual monitoring behavior, with mothers increasing their monitoring levels when infants were nearby (1-5 m), rather than within reach (0-1 m) or beyond nearby (>5 m). Additionally, the presence of kin and non-kin influenced monitoring: as the number of nearby kin increased, monitoring levels decreased, while the presence of more non-kin males led to an increase in monitoring time, and higher-ranking non-kin neighbors increased the frequency of monitoring. These results suggest that Tibetan macaque mothers can adapt their visual monitoring to the social risks faced by their infants, adjusting their strategies to their status and the needs of their offspring.

Structure and function of a ligand-free GPCR-Gαßγ intermediate complex.

Unraveling the signaling roles of intermediate complexes is pivotal for G protein-coupled receptor (GPCR) drug development. Despite hundreds of GPCR-Gαßγ structures, these snapshots primarily capture the fully activated complex. Consequently, the functions of intermediate GPCR-G protein complexes remain elusive. Guided by a conformational landscape visualized via 19F quantitative NMR and molecular dynamics (MD) simulation, we determined the structure of an intermediate GPCR-mini-Gαsßγ complex at 2.8 Å using cryo-EM, by blocking its transition to the fully activated complex. Furthermore, we presented direct evidence that the intermediate complex initiates a rate-limited nucleotide exchange without progressing to the fully activated complex, in which the α-helical domain (AHD) of the Gα is partially open engaged by a second nucleotide. Our MD simulation supported the pose of the AHD domain. These advances bridge a significant gap in our understanding the complexity of GPCR signaling.

Haplotype-phased genome unveils the butylphthalide biosynthesis and homoploid hybrid origin of Ligusticum chuanxiong.

Butylphthalide is one of the first-line drugs for ischemic stroke therapy, while no biosynthetic enzyme for butylphthalide has been reported. Here, we present a haplotype-resolved genome of Ligusticum chuanxiong, a long-cultivated and phthalide-rich medicinal plant in Apiaceae. On the basis of comprehensive screening, four Fe(II)- and 2-oxoglutarate-dependent dioxygenases and two CYPs were mined and further biochemically verified as phthalide C-4/C-5 desaturases (P4,5Ds) that effectively promoted the forming of (S)-3-n-butylphthalide and butylidenephthalide. The substrate promiscuity and functional redundancy featured for P4,5Ds may contribute to the high phthalide diversity in L. chuanxiong. Notably, comparative genomic evidence supported L. chuanxiong as a homoploid hybrid with Ligusticum sinense as a potential parent. The two haplotypes demonstrated exceptional structure variance and diverged around 3.42 million years ago. Our study is an icebreaker for the dissection of phthalide biosynthetic pathway and reveals the hybrid origin of L. chuanxiong, which will facilitate the metabolic engineering for (S)-3-n-butylphthalide production and breeding for L. chuanxiong.