Levo-tetrahydropalmatine: A new potential medication for methamphetamine addiction and neurotoxicity

A concise enzyme cascade enables the manufacture of natural and halogenated protoberberine alkaloids

The application and drug development of plant-derived natural products are often limited by their low abundance in medicinal plants and the lack of structural complexity and diversity. Herein, we design a concise enzyme cascade to efficiently produce natural and unnatural protoberberine alkaloids from cost-effective, readily available substrates. Through enzyme discovery and engineering, along with systematic optimization of the berberine bridge enzyme to address remaining manufacturing challenges in protoberberine alkaloid biosynthesis, the high production of drug Rotundine is achieved at an impressive gram-scale titer, demonstrating its industrial potential. More importantly, this cascade also enables the efficient biosynthesis of various unnatural halogenated protoberberine alkaloids. Thus, this work not only unlocks the potential of enzyme cascades in overcoming longstanding challenges in the efficient biosynthesis of plant-derived alkaloids, but also opens avenues to introduce structural complexity and diversity into alkaloids through synthetic biology, offering significant potential for drug development.

Tetrahydropalmatine ameliorates peripheral nerve regeneration by enhancing macrophage anti-inflammatory response

BACKGROUND

Peripheral nerve injury (PNI) is a common clinical problem that can result in partial or complete loss of sensory, motor, and autonomic functions. Tetrahydropalmatine (THP), a Corydalis yanhusuo-derived phytochemical alkaloid, possesses hypnotic, soothing, analgesic, and other effects, but little is known about the effect of THP on moderating peripheral nerve regeneration and its possible underlying mechanism of action.

PURPOSE

In this study, we aim to elucidate the protective function of THP on PNI and further reveal the underlying pharmacological mechanisms.

METHODS

PNI rats were in suit injection of THP solution at doses of 40 mg/kg for consecutive 3, 7, or 28 days, followed by harvesting the sciatic nerve tissues. The protective effect of THP on PNI was evaluated by electrophysiological test, transmission electron microscopy, immunofluorescence (IF), and western blotting (WB). Macrophage polarization, the expression of inflammatory-related genes and cytokines, and its upstream signaling pathways were detected by IF, WB, enzyme-linked immunosorbent assay (ELISA), mRNA-seq, and WB. In vitro, the Raw 264.7 cells were treated with lipopolysaccharide containing with/without THP. The degree of inflammatory activation and its potential pharmacological mechanism were measured by ELISA, qRT-PCR, IF staining, flow cytometry, and WB. Additionally, a pharmacological agonist or inhibitor was added to the cell medium to further identify the role of THP's potential pharmacological mechanism in regulating inflammatory response via IF and ELISA technology.

RESULTS

Using the sciatic nerve crush model, we found that THP significantly enhanced the rate of axonal growth and functional recovery, and altered macrophage subtype transformation from the M1/M0 phenotype into the M2 phenotype, inducing the secretion of large amounts of anti-inflammatory factors. Moreover, THP significantly increased the phosphorylation level of PI3K, AKT, GSK3β, and IκBa, and decreased the expression of TLR4 protein and NF-κB phosphorylation. Similarly, in vitro, THP also facilitated Raw 264.7 cell polarization to the M2 subtype under the condition of LPS stimulation. Meanwhile, the change of PI3K/AKT/GSK3β and TLR4/NF-κB signaling-related proteins in vitro was consistent with the results in vivo. Additionally, the THP-medicated anti-inflammatory effect on Raw 264.7 cells was partly eliminated when pharmacological intervention of these two signaling pathways.

CONCLUSIONS

THP has anti-inflammatory effects on facilitating M2-subtype macrophage polarization, which produces abundant anti-inflammatory cytokines to ameliorate peripheral nerve regeneration. Moreover, the potential mechanism of THP action may be intimately associated with activating the PI3K/AKT/GSK3β axis and inhibiting the TLR4/NF-κB pathway.

The analgesic effect and mechanism of the active components screening from Corydalis yanhusuo by P2X3 receptors

ETHNOPHARMACOLOGICAL RELEVANCE

Cavidine (CAV) is the main bioactive ingredient of Corydalis ternata f. yanhusuo (Y.H.Chou & Chun C.Hsu) Y.C.Zhu, which is a traditional Chinese herbal containing a variety of uses such as analgesic, anticancer, and anti-inflammatory properties.

AIM OF THE STUDY

The goal is to screen Corydalis yanhusuo for anti-central sensitization active components and investigate and clarify the pharmacological mechanism and therapeutic efficacy of the active ingredient CAV in the treatment of chronic pain.

MATERIAL AND METHODS

First, cell membrane immobilized chromatography was used to screen the bioactive ingredients in Corydalis yanhusuo. Spare nerve injury (SNI) model and complete Freund's adjuvant (CFA) mice model were constructed to identify the analgesic effect of CAV. RNA-seq and bioinformatics analyses were used to explore the potential targets of CAV in CFA mice and SNI mice. HE staining was used to observe the infiltration of inflammatory cells in the dorsal root ganglion (DRG) and spinal cord(SC) of CFA mice and SNI mice. WB and qPCR were used to detect the level of inflammatory factors TNF-α, IL-1β, and IL-6 in DRG and SC of mice. SNI and CFA mice were used to study the effect and mechanism of CAV on microglial activation.

RESULTS

9 potential active ingredients were screened out from Corydalis yanhusuo that can regulate P2X3 receptors. CAV showed good analgesic effects, increased the mechanical pain and thermal pain thresholds of CFA mice and SNI mice, inhibited the expression of DRG and SC inflammatory factors, downregulated IBA-1, and inhibited microglial activation. Further in vivo and in vitro experiments showed that CAV significantly inhibited the expression of P2X3 receptors and the activation of its downstream MAPK pathway in DRG neurons and SC.

CONCLUSION

This study is the first to indicate that CAV exerts an analgesic effect by inhibiting microglia activation via the P2X3 signaling pathway axis, providing the clinical utility of CAV in chronic pain therapy.

Exploring the mechanism and effective compounds of Changan Granule on diarrhea-predominant irritable bowel syndrome via regulating 5-hydroxytryptamine signaling pathway in brain-gut axis

BACKGROUND

Changan Granule (CAG) is a drug product developed from a traditional Chinese medicine (TCM) empirical prescription for diarrhea-predominant irritable bowel syndrome (IBS-D). The action mechanism and effective compounds of CAG in the treatment of IBS-D are not well understood.

PURPOSE

This study aimed to investigate the effectiveness, action mechanism and effective compounds of CAG for treating IBS-D.

METHODS

Network pharmacology was used to screen the related pathways and active compounds of CAG in the treatment of IBS-D. Neonatal mother-infant separation, acetic acid enema and colorectal dilation were employed to construct IBS-D model for in vivo study. The effectiveness of CAG was evaluated in accordance with the results of body weight measurement, fecal water content determination, abdominal withdraw reflex test, open field test, sucrose preference test, forced swimming test and hematoxylin-eosin (HE) staining. The protein and mRNA levels of key molecules regulated by CAG were assessed through enzyme-linked immunosorbent assay (ELISA), western blotting, and reverse transcription quantitative polymerase chain reaction (RT-qPCR). The active compounds from CAG screened by network pharmacology were investigated with Caco-2 and RIN-14B cell models in vitro.

RESULTS

Network pharmacological analysis showed that CAG regulated 5-hydroxytryptamine (5-HT) signaling pathway and tetrahydropalmatine, formononetin and corydaline might be the potential effective compounds. The validation experiments showed that CAG restored the decreased body weight, and alleviated intestinal sensitivity, low-grade inflammation, diarrhea, frequent defecation, anxiety and depression of IBS-D rats through regulating the expression levels of 5-HT, tryptophan hydroxylase (TPH)1/2, serotonin transporter (SERT), 5-hydroxytryptamine-3 and -4 receptors (5-HT3R and 5-HT4R) in brain-gut axis (BGA). Tetrahydropalmatine and formononetin were confirmed to be the potential effective compounds of CAG in regulating 5-HT signaling pathway.

CONCLUSION

CAG exhibits therapeutic effect on IBS-D rats through regulating 5-HT signaling pathway in BGA. Tetrahydropalmatine and formononetin are major potential effective compounds. Our findings provide scientific basis for the clinical use and drug development of CAG for IBS-D.

Integration of pharmacochemistry, pharmacodynamics and metabolomics to reveal active ingredients and mechanism of Nan Bao detox capsule alleviating methamphetamine addiction

Nan Bao detox capsule (NBDC), derived from ancient Chinese opioid detox protocols, shows promising therapeutic potential in substance abuse disorders, particularly for attenuating methamphetamine (MA) addiction. This study aimed to identify active ingredients, evaluate therapeutic efficacy in an MA addiction rat model and delineate pharmacodynamic mechanisms using metabolomics. In vitro phytochemical profiling characterized 258 drug-related compounds, with 87 prototype entities mainly identified in rat plasma. NBDC significantly attenuated METH-induced behavioural anomalies and modulated neurotransmitter levels, notably increasing brain DA and serotonin (5-HT) content with concomitant upregulation of D1 dopamine receptor (DRD1) and 5-HT1A receptor (5-HT1AR) expression, ameliorating hippocampal pathology. Metabolomic analysis identified histamine receptor as a potential target and revealed the involvement of NBDC in metabolic pathways associated with cocaine addiction, amphetamine abuse and Parkinson's disease. Conclusively, NBDC presents a promising therapeutic agent for mitigating MA addiction through a synergistic interplay of multiple constituents, pharmacological targets and metabolic pathways.

Mechanisms and treatments of methamphetamine and HIV-1 co-induced neurotoxicity: a systematic review

Combination antiretroviral therapy (cART) has dramatically reduced mortality in people with human immunodeficiency virus (HIV), but it does not completely eradicate the virus from the brain. Patients with long-term HIV-1 infection often show neurocognitive impairment, which severely affects the quality of life of those infected. Methamphetamine (METH) users are at a significantly higher risk of contracting HIV-1 through behaviors such as engaging in high-risk sex or sharing needles, which can lead to transmission of the virus. In addition, HIV-1-infected individuals who abuse METH exhibit higher viral loads and more severe cognitive dysfunction, suggesting that METH exacerbates the neurotoxicity associated with HIV-1. Therefore, this review focuses on various mechanisms underlying METH and HIV-1 infection co-induced neurotoxicity and existing interventions targeting the sigma 1 receptor, dopamine transporter protein, and other relevant targets are explored. The findings of this review are envisaged to systematically establish a theoretical framework for METH abuse and HIV-1 infection co-induced neurotoxicity, and to suggest novel clinical treatment targets.

NMDA Receptor Modulation in COVID-19-Associated Acute Respiratory Syndrome in both In Silico and In Vitro Approach

The normal function of the N-methyl D-aspartate receptors (NMDAR) in human lungs depends on precisely regulated synaptic glutamate levels. Pathophysiology of the lungs is brought on by the changes in homeostasis of glutamate in the synapsis that leads to abnormal NMDAR activity. Severe acute respiratory syndrome (SARS) primarily results in lung infections, particularly lung muscle stiffening, and NMDA receptor potentiation may increase calcium ion influx and support downstream signaling mechanisms. Hence, NMDAR modulators that depend on glutamate levels could be therapeutically useful medications with fewer unintended side effects. A compound called THP (tetrahydropalmatine) that amplifies Ca2+ influx and potentiates NMDA receptors has been identified in the current study. In asthmatic human airway smooth muscle (HASM) cells, THP regulates the NMDA receptor and helps in asthmatic ASM contraction, and the pharmacological stimulation of ASM depends on both brain and respiratory NMDA receptors. Glutamate potency is altered by this substance without any voltage-dependent side effects. Additionally, a GGPP (geranylgeranyl pyrophosphate)-dependent mechanism of THP reduced the production of pro-inflammatory cytokines in ASM. THP is distinctive in terms of its chemical makeup, functioning, and agonist concentration-dependent and allosteric modulatory activity. To treat COVID-19-related SARS, THP, or any future-related compounds will make good drug-like molecule candidates.

Research Progress on Neuroprotective Effects of Isoquinoline Alkaloids

Neuronal injury and apoptosis are important causes of the occurrence and development of many neurodegenerative diseases, such as cerebral ischemia, Alzheimer's disease, and Parkinson's disease. Although the detailed mechanism of some diseases is unknown, the loss of neurons in the brain is still the main pathological feature. By exerting the neuroprotective effects of drugs, it is of great significance to alleviate the symptoms and improve the prognosis of these diseases. Isoquinoline alkaloids are important active ingredients in many traditional Chinese medicines. These substances have a wide range of pharmacological effects and significant activity. Although some studies have suggested that isoquinoline alkaloids may have pharmacological activities for treating neurodegenerative diseases, there is currently a lack of a comprehensive summary regarding their mechanisms and characteristics in neuroprotection. This paper provides a comprehensive review of the active components found in isoquinoline alkaloids that have neuroprotective effects. It thoroughly explains the various mechanisms behind the neuroprotective effects of isoquinoline alkaloids and summarizes their common characteristics. This information can serve as a reference for further research on the neuroprotective effects of isoquinoline alkaloids.

Methamphetamine: Mechanism of Action and Chinese Herbal Medicine Treatment for Its Addiction

With the proliferation of synthetic drugs, research on the mechanism of action of addictive drugs and treatment methods is of great significance. Among them, methamphetamine (METH) is the most representative amphetamine synthetic drug, and the treatment of METH addiction has become an urgent medical and social problem. In recent years, the therapeutic effects of Chinese herbal medicines on METH addiction have gained widespread attention because of their non-addictiveness, multiple targets, low side effects, low cost, and other characteristics. Previous studies have identified a variety of Chinese herbal medicines with effects on METH addiction. Based on the research on METH in recent years, this article summarizes the mechanism of action of METH as the starting point and briefly reviews the Chinese herbal medicine-based treatment of METH.

Nanowired Delivery of Mesenchymal Stem Cells with Antioxidant Compound H-290/51 Reduces Exacerbation of Methamphetamine Neurotoxicity in Hot Environment

Military personnel are often exposed to hot environments either for combat operations or peacekeeping missions. Hot environment is a severe stressful situation leading to profound hyperthermia, fatigue and neurological impairments. To avoid stressful environment, some people frequently use methamphetamine (METH) or other psychostimulants to feel comfortable under adverse situations. Our studies show that heat stress alone induces breakdown of the blood-brain barrier (BBB) and edema formation associated with reduced cerebral blood flow (CBF). On the other hand, METH alone induces hyperthermia and neurotoxicity. These effects of METH are exacerbated at high ambient temperatures as seen with greater breakdown of the BBB and brain pathology. Thus, a combination of METH use at hot environment may further enhance the brain damage-associated behavioral dysfunctions. METH is well known to induce severe oxidative stress leading to brain pathology. In this investigation, METH intoxication at hot environment was examined on brain pathology and to explore suitable strategies to induce neuroprotection. Accordingly, TiO₂-nanowired delivery of H-290/51 (150 mg/kg, i.p.), a potent chain-breaking antioxidant in combination with mesenchymal stem cells (MSCs), is investigated in attenuating METH-induced brain damage at hot environment in model experiments. Our results show that nanodelivery of H-290/51 with MSCs significantly enhanced CBF and reduced BBB breakdown, edema formation and brain pathology following METH exposure at hot environment. These observations are the first to point out that METH exacerbated brain pathology at hot environment probably due to enhanced oxidative stress, and MSCs attenuate these adverse effects, not reported earlier.

A Comprehensive Review on the Chemical Properties, Plant Sources, Pharmacological Activities, Pharmacokinetic and Toxicological Characteristics of Tetrahydropalmatine

Tetrahydropalmatine (THP), a tetrahydroproberine isoquinoline alkaloid, is widely present in some botanical drugs, such as Stephania epigaea H.S. Lo (Menispermaceae; Radix stephaniae epigaeae), Corydalis yanhusuo (Y.H.Chou & Chun C.Hsu) W.T. Wang ex Z.Y. Su and C.Y. Wu (Papaveraceae; Corydalis rhizoma), and Phellodendron chinense C.K.Schneid (Berberidaceae; Phellodendri chinensis cortex). THP has attracted considerable attention because of its diverse pharmacological activities. In this review, the chemical properties, plant sources, pharmacological activities, pharmacokinetic and toxicological characteristics of THP were systematically summarized for the first time. The results indicated that THP mainly existed in Papaveraceae and Menispermaceae families. Its pharmacological activities include anti-addiction, anti-inflammatory, analgesic, neuroprotective, and antitumor effects. Pharmacokinetic studies showed that THP was inadequately absorbed in the intestine and had rapid clearance and low bioavailability in vivo, as well as self-microemulsifying drug delivery systems, which could increase the absorption level and absorption rate of THP and improve its bioavailability. In addition, THP may have potential cardiac and neurological toxicity, but toxicity studies of THP are limited, especially its long-duration and acute toxicity tests. In summary, THP, as a natural alkaloid, has application prospects and potential development value, which is promising to be a novel drug for the treatment of pain, inflammation, and other related diseases. Further research on its potential target, molecular mechanism, toxicity, and oral utilization should need to be strengthened in the future.

Peanut Rotation and Flooding Induce Rhizobacteriome Variation With Opposing Influences on the Growth and Medicinal Yield of Corydalis yanhusuo

Corydalis yanhusuo, a precious herb of the Papaveraceae family, is widely used in multiple traditional Chinese medicines for the treatment of many painful conditions, and its medicinal part is the dried tuber. Yet how to improve this plant's medicinal yield as well as its economic efficiency remains a key problem in its cultivation. The planting of C. yanhusuo in rotation with peanut (Arachis hypogaea L.) aims to improve land utilization efficiency, but the total production of tubers is severely reduced relative to fields without rotation. However, an increased yield was observed in C. yanhusuo plants grown in previously flooded fields (HR field) compared to the ones grown in the fields that had been used to cultivate peanut (PL field) or in fields without rotation or flooding (N field). Based on these phenomena, in this study, we explored the potential factors responsible for the altered growth/yield of C. yanhusuo under different field conditions. Soil physicochemical properties and the diversity and community of rhizobacteriome of C. yanhusuo were both analyzed. By testing several soil physicochemical properties, we found that the cation exchange capacity (CEC), soil organic matter (SOM), total nitrogen (TN), and pH value differed significantly among these three types of fields. 16S rRNA amplicon sequencing revealed stark differences in the composition, diversity, and potential functions of the bacterial community in the rhizosphere of C. yanhusuo plants grown in field with the peanut rotation or flooding. Notably, the Acidobacteria were enriched in the HR field, while Actinobacteria were enriched in the PL field. More importantly, further analysis showed that changed soil physicochemical properties could be one reason for why the rhizospheric bacterial community has changed; hence, soil physicochemical properties might also be affecting plant performance indirectly by regulating the rhizospheric bacterial community. The RDA analysis distinguished CEC as the most important soil physicochemical property influencing the structure and composition of the C. yanhusuo rhizobacteriome. In summary, our results suggest peanut rotation- and flooding-induced soil physicochemical properties changes would further impact the rhizobacteriome of C. yanhusuo albeit differentially, culminating in opposite effects upon the plant growth and medicinal yield of C. yanhusuo.