Anti-Hypoxic Molecular Mechanisms of Rhodiola crenulata Extract in Zebrafish as Revealed by Metabonomics

Molecular pathways in cardiovascular disease under hypoxia: Mechanisms, biomarkers, and therapeutic targets

Chronic hypoxia is a key factor in the pathogenesis of cardiovascular diseases, including ischemia, heart failure, and hypertension. Under hypoxic conditions, oxygen deficiency disrupts oxidative phosphorylation in mitochondria, impairing ATP production and generating reactive oxygen species (ROS). These reactive species induce mitochondrial dysfunction, leading to oxidative stress, calcium imbalance, and activation of apoptosis pathways. Mitochondrial K-ATP (mitoK-ATP) and mitochondrial permeability transition pore (mPTP) channels are particularly affected, contributing to membrane potential loss, cytochrome C release, and cell death. This review explores the molecular mechanisms underlying hypoxia-induced cardiovascular diseases, with a focus on mitochondrial impairment, ion channel dysfunction, and ROS overproduction. Additionally, we examine hypoxia-inducible factor 1-alpha (HIF-1α) as a biomarker of cellular adaptation and discuss therapeutic strategies targeting mitochondrial function and oxidative stress. Antioxidants and compounds modulating key ion channels, such as K-ATP and mPTP, are highlighted as promising interventions for mitigating hypoxia-induced damage. Furthermore, we emphasize the potential of integrating in vitro, in vivo, and in silico studies to develop novel therapies aimed at preserving mitochondrial integrity and preventing cardiovascular diseases.

Citrate: a key signalling molecule and therapeutic target for bone remodeling disorder

Bone remodeling is a continuous cyclic process that maintains and regulates bone structure and strength. The disturbance of bone remodeling leads to a series of bone metabolic diseases. Recent studies have shown that citrate, an intermediate metabolite of the tricarboxylic acid (TCA) cycle, plays an important role in bone remodeling. But the exact mechanism is still unclear. In this study, we focused on the systemic regulatory mechanism of citrate on bone remodeling, and found that citrate is involved in bone remodeling in multiple ways. The participation of citrate in oxidative phosphorylation (OXPHOS) facilitates the generation of ATP, thereby providing substantial energy for bone formation and resorption. Osteoclast-mediated bone resorption releases citrate from bone mineral salts, which is subsequently released as an energy source to activate the osteogenic differentiation of stem cells. Finally, the differentiated osteoblasts secrete into the bone matrix and participate in bone mineral salts formation. As a substrate of histone acetylation, citrate regulates the expression of genes related to bone formation and bone reabsorption. Citrate is also a key intermediate in the metabolism and synthesis of glucose, fatty acids and amino acids, which are three major nutrients in the organism. Citrate can also be used as a biomarker to monitor bone mass transformation and plays an important role in the diagnosis and therapeutic evaluation of bone remodeling disorders. Citrate imbalance due to citrate transporter could result in the supression of osteoblast/OC function through histone acetylation, thereby contributing to disorders in bone remodeling. Therefore, designing drugs targeting citrate-related proteins to regulate bone citrate content provides a new direction for the drug treatment of diseases related to bone remodeling disorders.

Multi-omics analysis reveals phenylalanine enhance mitochondrial function and hypoxic endurance via LKB1/AMPK activation

Many studies have focused on the effects of small molecules, such as amino acids, on metabolism under hypoxia. Recent findings have indicated that phenylalanine levels were markedly elevated in adaptation to chronic hypoxia. This raises the possibility that phenylalanine treatment could markedly improve the hypoxic endurance. However, the importance of hypoxia-regulated phenylalanine is still unclear. This study investigates the role of phenylalanine in hypoxia adaptation using a hypoxic zebrafish model and multi-omics analysis. We found that phenylalanine-related metabolic pathways are significantly up-regulated under hypoxia, contributing to enhanced hypoxic endurance. Phenylalanine treatment reduced ROS levels, improved mitochondrial oxygen consumption rate (OCR), and extracellular acidification rate (ECAR) in hypoxic cells. Western blotting revealed increased phenylalanine uptake via L-type amino transporters (LAT1), activating the LKB1/AMPK signaling pathway. This activation up-regulated peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) and the Bcl-2/Bax ratio, while down-regulating uncoupling protein 2 (UCP2), thereby improving mitochondrial function under hypoxia. This is the first comprehensive multi-omics analysis to demonstrate phenylalanine's crucial role in hypoxia adaptation, providing insights for the development of anti-hypoxic drugs.

Lysophospholipid acyltransferase-mediated formation of saturated glycerophospholipids maintained cell membrane integrity for hypoxic adaptation

Adaptation to hypoxia has attracted much public interest because of its clinical significance. However, hypoxic adaptation in the body is complicated and difficult to fully explore. To explore previously unknown conserved mechanisms and key proteins involved in hypoxic adaptation in different species, we first used a yeast model for mechanistic screening. Further multi-omics analyses in multiple species including yeast, zebrafish and mice revealed that glycerophospholipid metabolism was significantly involved in hypoxic adaptation with up-regulation of lysophospholipid acyltransferase (ALE1) in yeast, a key protein for the formation of dipalmitoyl phosphatidylcholine [DPPC (16:0/16:0)], which is a saturated phosphatidylcholine. Importantly, a mammalian homolog of ALE1, lysophosphatidylcholine acyltransferase 1 (LPCAT1), enhanced DPPC levels at the cell membrane and exhibited the same protective effect in mammalian cells under hypoxic conditions. DPPC supplementation effectively attenuated growth restriction, maintained cell membrane integrity and increased the expression of epidermal growth factor receptor under hypoxic conditions, but unsaturated phosphatidylcholine did not. In agreement with these findings, DPPC treatment could also repair hypoxic injury of intestinal mucosa in mice. Taken together, ALE1/LPCAT1-mediated DPPC formation, a key pathway of glycerophospholipid metabolism, is crucial for cell viability under hypoxic conditions. Moreover, we found that ALE1 was also involved in glycolysis to maintain sufficient survival conditions for yeast. The present study offers a novel approach to understanding lipid metabolism under hypoxia and provides new insights into treating hypoxia-related diseases.

Clinical effects of traditional Chinese herbal medicine management in patients with COVID-19 sequelae: A hospital-based retrospective cohort study in Taiwan

Introduction: An estimated 43% of COVID-19 patients showed sequelae, including fatigue, neurocognitive impairment, respiratory symptoms, and smell or taste disorders. These sequelae significantly affect an individual's health, work capacity, healthcare systems, and socioeconomic aspects. Traditional Chinese herbal medicine (TCHM) management showed clinical benefits in treating patients with COVID-19 sequelae. This study aimed to analyze the effects of personalized TCHM management in patients with COVID-19 sequelae. Methods: After the COVID-19 outbreak in Taiwan, we recorded Chronic Obstructive Pulmonary Disease Assessment Tool (CAT), Chalder Fatigue Questionnaire (CFQ-11), and Brief Symptom Rating Scale (BSRS-5) to assess post-COVID respiratory, fatigue, and emotional distress symptoms, respectively. In this study, we retrospectively reviewed the medical records between July 2022 and March 2023. We analyzed the effects of TCHM administration after 14- and 28-days of treatment. Results: 47 patients were included in this study. The results demonstrated that personalized TCHM treatment significantly improved the CAT, CFQ-11, and BSRS-5 scores after 14 and 28 days. TCHM alleviated physical and psychological fatigue. In logistic regression analysis, there was no statistically significant differences in the severity of the baseline symptoms and TCHM administration effects concerning the duration since the initial confirmation of COVID-19, sex, age, or dietary preference (non-vegetarian or vegetarian). Conclusions: Our study suggested that personalized TCHM treatment notably reduced fatigue, respiratory and emotional distress symptoms after 14- and 28-days of treatment in patients with COVID-19 sequelae. We propose that TCHM should be considered as an effective intervention for patients with COVID-19 sequelae.

Salidroside inhibits renal ischemia/reperfusion injury‑induced ferroptosis by the PI3K/AKT signaling pathway

Renal ischemia/reperfusion injury (RIRI) represents the principal factor underlying acute kidney injury (AKI), which primarily stems from cellular injuries and ferroptosis caused by reactive oxygen species (ROS). Salidroside (SA), an antioxidant natural ester, has been attributed with the potential to protect against RIRI. In the present study, rats received daily SA doses (1, 10, or 100 mg/kg) by gavage for 7 consecutive days before surgery. The results revealed aggravated renal injury in the RIRI group, which was effectively prevented by SA pretreatment (10 and 100 mg/kg), with the 1 mg/kg dosage demonstrating lesser efficacy. Additionally, the results indicated that SA pretreatment mitigated the RIRI-related upregulation of antioxidative superoxide dismutase. In vitro studies corroborated SA's ability to maintain hypoxia/reoxygenation-treated NRK cell viability, with the protective effect being observed at SA concentrations ≥1 µM and peaking at 100 µM. Furthermore, the results showed that SA safeguarded renal tubular epithelial cells from oxidative damage, reduced ROS accumulation, and inhibited ferroptosis via activation of the PI3K/AKT signaling pathway. Therefore, the results of the present study highlight the promising therapeutic potential of SA as an effective intervention for RIRI via targeting of PI3K/AKT signaling pathway-mediated anti-oxidative and anti-ferroptotic mechanisms.

Isopropyl 3-(3,4-dihydroxyphenyl)-2-hydroxypropanoate plays an anti-hypoxic role through regulating neuroactive ligand-receptor interaction signaling pathway in larval zebrafish

Isopropyl 3-(3,4-dihydroxyphenyl)-2-hydroxypropanoate (IDHP) is the core active substance of salvia miltiorrhiza in disease treatment. The significance of our work lies in evaluating the ameliorating effects of IDHP on hypoxia-induced injury and investigating its mechanisms. We examined the morphology, dopamine neurons (DANs), cerebral vessels, and behavior of zebrafish larvae administrated by IDHP/VHC after hypoxia-induction. We next sought to explore its anti-hypoxic mechanisms via transcriptome analysis and qPCR experiments. The results indicated that hypoxia-induced injuries, including decreased length of DANs, number of cereal vessels, total swimming distance, and average swimming speed, were all alleviated by IDHP. Furthermore, transcriptome analysis provided a sign that IDHP most likely played the anti-hypoxic role through the neuroactive ligand-receptor interaction (NLRI) signaling pathway. Consistently, expression of related genes, such as f2rl1.1, p2ry10, npy1r, ptger2b, ptger2b, pth2rb, and nmur1a, was downregulated by hypoxia induction and recovered after IDHP administration. Therefore, we speculated that, via regulating NLRI, IDHP reduced inflammation, promoted angiogenesis, modulated blood pressure and flow, and inhibited cell apoptosis, and eventually played an anti-hypoxic role.

Metabolic responses of golden trout (Oncorhynchus mykiss aguabonita) after acute exposure to waterborne copper

Despite the broad knowledge of copper-induced stress and toxicity, data on the physiological responses to acute copper exposure and the correlation of those activities to a generalized stress response are still limited. The present study aimed to assess the physiological responses of golden trout to overcome copper stress at concentrations of 60 µg/L and 120 µg/L after 96 h, respectively. The activities of glucose-6-phosphate dehydrogenase (G6PD) phosphoenolpyruvate carboxykinase (PEPCK) and NADPH/NADP⁺ ratio were significantly increased, and metabolites including glucose 6-phosphate, fructose 1-phosphate and fatty acids significantly accumulated in fish liver, indicating that gluconeogenesis, the pentose-phosphate pathway, as well as alteration of the membrane fatty acid composition were activated to serve as a defense mechanism against 60 µg/L of copper after 96 h. After exposure to 120 µg/L of copper for 96 h, the NAD⁺ and ATP contents, the activities of enzymes in the glycolytic pathway (phosphofructokinase, PFK and pyruvate kinase, PK) and mitochondrial respiratory chain complex I decreased significantly in fish liver. In addition, carbohydrates and MDA accumulated in golden trout after 120 µg/L copper treatment. These results indicated that 120 µg/L of copper exposure may induce a metabolic stress in golden trout after 96 h. The multi-marker approach allows us to reach a greater understanding of the effects of copper on physiological responses of golden trout.

Reveal the Antimigraine Mechanism of Chuanxiong Rhizoma and Cyperi Rhizoma Based on the Integrated Analysis of Metabolomics and Network Pharmacology

Migraine is a common neurological disorder that manifests as recurrent attacks of unilateral and throbbing headache. Conioselinum anthriscoides “Chuanxiong” (Apiaceae; Chuanxiong rhizoma) and Cyperus rotundus L. (Cyperaceae; Cyperi rhizoma) (CRCR), is a classic prescription for treating migraine. This study aimed to reveal the potential mechanisms of CRCR extract against migraine using integrated analysis of metabolomics and network pharmacology. Behavioral changes in the nitroglycerin rat migraine model were determined from von Frey withdrawal response. Untargeted serum metabolomics was used to identify the differentially expressed metabolites and metabolic pathways. The differentially expressed metabolites were analyzed to obtain the corresponding targets by a compound–reaction–enzyme–gene network. Network pharmacology was used to construct a compound–target–pathway network. The common targets of metabolomics and network pharmacology were further analyzed. Metabolomics analysis identified 96 differentially expressed metabolites and 77 corresponding targets. Network pharmacology analysis identified 201 potential targets for CRCR against migraine. By intersecting 77 targets with 201 targets, monoamine oxidase A (MAO-A), monoamine oxidase B (MAO-B), and catechol-O-methyltransferase (COMT) were identified as the common targets, and MAO-A, MAO-B, and COMT were involved in the tyrosine metabolism pathway. Further experiments demonstrated that the contents of MAO-A and COMT were significantly increased in serum and brainstem tissue of the migraine rats. CRCR extract significantly decreased the contents of MAO-A and COMT, while no significant difference was found in MAO-B. Metabolomics analysis indicated that the contents of 3,4-dihydroxyphenylacetate (DOPAC) and 3-(4-hydroxyphenyl)pyruvate (HPP) were significantly increased in the migraine rats, and CRCR extract caused significant decreases in DOPAC and HPP. Interestingly, DOPAC and HPP were two differentially expressed metabolites involved in the tyrosine metabolism pathway. Correlation analysis showed that DOPAC and HPP were highly positively correlated with MAO-A and COMT. Taken together, two key differentially expressed metabolites (DOPAC and HPP), two key targets (MAO-A and COMT), and one relevant metabolic pathway (tyrosine metabolism) showed great importance in the treatment of migraine. This research could provide a new understanding of the potential mechanism of CRCR against migraine. More attentions should be paid into the tyrosine metabolism pathway in future studies.

Tralopyril affects locomotor activity of zebrafish (Danio rerio) by impairing tail muscle tissue, the nervous system, and energy metabolism

Tralopyril (TP), an antifouling biocide, is widely used to prevent heavy biofouling, and can have potential risks to aquatic organisms. In this study, the effect of TP on locomotor activity and related mechanisms were evaluated in zebrafish (Danio rerio) larvae. TP significantly reduced locomotor activity after 168 -h exposure. Adverse modifications in tail muscle tissue, the nervous system, and energy metabolism were also observed in larvae. TP caused thinning of the muscle bundle in the tail of larvae. In conjunction with the metabolomics results, changes in dopamine (DA) and acetylcholine (ACh), acetylcholinesterase (AChE) activity, and the expression of genes involved in neurodevelopment, indicate that TP may disrupt the nervous system in zebrafish larvae. The change in metabolites (e.g., glucose 6-phosphate, cis-Aconitic acid, acetoacetyl-CoA, coenzyme-A and 3-Oxohexanoyl-CoA) involved in carbohydrate and lipid metabolism indicates that TP may disrupt energy metabolism. TP exposure may inhibit the locomotor activity of zebrafish larvae by impairing tail muscle tissue, the nervous system, and energy metabolism.

Nobiletin, a hexamethoxyflavonoid from citrus pomace, attenuates G1 cell cycle arrest and apoptosis in hypoxia-induced human trophoblast cells of JEG-3 and BeWo via regulating the p53 signaling pathway

Background

Hypoxia is associated with abnormal cell apoptosis in trophoblast cells, which causes fetal growth restriction and related placental pathologies. Few effective methods for the prevention and treatment of placenta-related diseases exist. Natural products and functional foods have always been a rich source of potential anti-apoptotic drugs. Nobiletin (NOB), a hexamethoxyflavonoid derived from the citrus pomace, shows an anti-apoptotic activity, which is a non-toxic constituent of dietary phytochemicals approved by the Food and Drug Administration. However, their effects on hypoxia-induced human trophoblast cells have not been fully studied.

Objective

The aim of this study was to investigate the protective effects of NOB on hypoxia-induced apoptosis of human trophoblast JEG-3 and BeWo cells, and their underlying mechanisms.

Design

First, the protective effect of NOB on hypoxia-induced apoptosis of JEG-3 and BeWo cells was studied. Cell viability and membrane integrity were determined by CCK-8 assay and lactate dehydrogenase activity, respectively. Real Time Quantitative PCR (RT-qPCR) and Western blot analysis were used to detect the mRNA and protein levels of HIF1α. Propidium iodide (PI)-labeled flow cytometry was used to detect cell cycle distribution. Cell apoptosis was detected by flow cytometry with Annexin V-FITC and PI double staining, and the expression of apoptosis marker protein cl-PARP was detected by Western blot analysis. Then, the molecular mechanism of NOB against apoptosis was investigated. Computer molecular docking and dynamics were used to simulate the interaction between NOB and p53 protein, and this interaction was verified in vitro by Ultraviolet and visible spectrum (UV-visible spectroscopy), fluorescence spectroscopy and circular dichroism. Furthermore, the changes in the expression of p53 signaling pathway genes and proteins were detected by RT-qPCR and Western blot analysis, respectively.

Results

Hypoxia treatment resulted in a decreased cell viability and cell membrane integrity in JEG-3 and BeWo cell lines, and an increased expression of HIF1α, cell cycle arrest in the G1 phase, and massive cell apoptosis, which were alleviated after NOB treatment. Molecular docking and dynamics simulations found that NOB spontaneously bonded to human p53 protein, leading to the change of protein conformation. The intermolecular interaction between NOB and human p53 protein was further confirmed by UV-visible spectroscopy, fluorescence spectroscopy and circular dichroism. After the treatment of 100 μM NOB, a down-regulation of mRNA and protein levels of p53 and p21 and an up-regulation of BCL2/BAX mRNA and protein ratio were observed in JEG-3 cells; however, there was also a down-regulation of mRNA and protein levels observed for p53 and p21 in BeWo cells after the treatment of NOB. The BCL2/BAX ratio of BeWo cells did not change after the treatment of 100 μM NOB.

Conclusion

NOB attenuated hypoxia-induced apoptosis in JEG-3 and BeWo cell lines and might be a potential functional ingredient to prevent pregnancy-related diseases caused by hypoxia-induced apoptosis. These findings would also suggest the exploration and utilization of citrus resources, and the development of citrus industry.

Rapid identification of chemical constituents of Rhodiola crenulata using liquid chromatography-mass spectrometry pseudotargeted analysis

Rhodiola crenulata (R. crenulata), is a famous traditional Chinese medicine, with observable effects such as anti-high-altitude illness and fatigue resistance. Nevertheless, comprehensive and systematic structural identification of its components remains a challenge. In this study, a pseudotargeted analytical method, involving key fragment filtering by ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry and ultra-high performance liquid chromatography-linear ion trap-Orbitrap mass spectrometry, was developed for rapid detection and identification of the chemical constituents of R. crenulata. The process consists of three steps: (i) acquiring sufficient mass spectral data, (ii) constructing a key fragments schedule and discovering the substructures rapidly by pseudotargeted key fragment filtering, and (iii) further identification of the compound structures based on accurate masses, fragment ions, related literatures, and authentic standards. As a result, 104 compounds were identified and divided into five categories, among which three potentially new and 59 ones were reported for the first time in R. crenulata. These results indicated that the major types of components are flavanols and gallic acid derivatives, organic acids, alcohols and their glycosides, flavonoids and their glycosides. This study enhances the understanding of R. crenulata and provides a reference for rapid and comprehensive identification of constituents in other herbal medicines.