Comprehensive Analysis of the Effect of 20(R)-Ginsenoside Rg3 on Stroke Recovery in Rats via the Integrative miRNA-mRNA Regulatory Network

20(R)-ginsenoside Rg3 protects against focal cerebral ischemia‒reperfusion injury by suppressing autophagy via PI3K/Akt/mTOR signaling pathway

OBJECTIVE

This study aimed to investigate the effect of 20(R)-ginsenoside Rg3 on autophagy induced by cerebral ischemia‒reperfusion injury (CIRI) in rats and explore its regulation of the PI3K/Akt signaling pathway.

METHODS

Middle cerebral artery occlusion/reperfusion (MCAO/R) in male rats was injected intraperitoneally with 20(R)-ginsenoside Rg3 (5, 10, 20 mg/kg) 12 h before modeling, 2 h after ischemia and 12 h after reperfusion. Neurobehavioral and neuronal morphological changes were detected 24 h after brain I/R. In vitro, the OGD/R-induced injury model is replicated in PC12 cells and different concentrations of 20(R)-ginsenoside Rg3 are administered to observe its effects on cell viability and autophagy and PI3K/Akt/mTOR-related protein expression.

RESULTS

Our findings suggest that treatment with 20 mg/kg 20(R)-ginsenoside Rg3 significantly attenuated the neuronal injury, as evidenced by a decreased number of damaged neurons, reduced dissolution of Nissl corpuscles, a fewer autophagosomes, and downregulated expression of Beclin1 and LC3-II/I compared with the MCAO/R group. Furthermore, 20(R)-ginsenoside Rg3 treatment significantly upregulated the expression of p62, p-PI3K, p-AKT, and p-mTOR. In vitro, 20(R)-ginsenoside Rg3 significantly improved the survival rate of cells following OGD/R and markedly attenuated the LY294002 and OGD/R-induced upregulation of Beclin1 and LC3 gene expression. Moreover, 20(R)-ginsenoside Rg3 could rescued the LY294002 and OGD/R-induced downregulation of p62, p-PI3K, p-AKT, and p-mTOR expression.

CONCLUSIONS

20(R)-ginsenoside Rg3 attenuates neuronal injury and motor dysfunction following ischemia-reperfusion by inhibiting the activation of autophagy, and its mechanism is related to the upregulation of the PI3K/Akt/mTOR signaling pathway.

Ginsenoside Rg3 improves microcystin-induced cardiotoxicity through the miR-128-3p/MDM4 axis

Microcystin (MC) is the byproduct of cyanobacteria metabolism that is associated with oxidative stress and heart damage. This study aimed to investigate the effect of ginsenoside Rg3 on MC-induced cardiotoxicity. A mouse model of myocardial infarction was constructed by oral MC administration. H9C2 cells were used for in vitro analysis. Cellular oxidative stress, apoptosis, and the relationship between miR-128-3p and double minute 4 protein (MDM4) were analyzed. MiR-128-3p expression was upregulated in vitro and in vivo after MC treatment, which was downregulated after Rg3 treatment. Left ventricular ejection fraction (LVEF) and left ventricular systolic pressure (LVSP) were increased and left ventricular end-diastolic pressure (LVEDP) was decreased after Rg3 treatment. Moreover, Rg3 alleviated MC-induced pathological changes and apoptosis in myocardial tissues. Meanwhile, Rg3 treatment decreased the lactate dehydrogenase (LDH) and malondialdehyde (MDA) levels and inhabited cell apoptosis and oxidative stress in MC-treated myocardial cells. MiR-128-3p overexpression attenuated the protective effect of Rg3 on MC-induced cardiotoxicity. MiR-128-3p negatively regulated MDM4 expression. This study revealed that Rg3 alleviated MC-induced cardiotoxicity through the miR-128-3p/MDM4 axis, which emphasized the potential of Rg3 as a therapeutic agent for MC-induced cardiotoxicity, and miR-128-3p as a target for the Rg3 therapy.

Exploring 3-O-glycosylations of 20(R)-dammarane ginsenosides and the catalytic mechanism underlying the stereoselectivity with the combined assistance of AlphaFold 2 and molecular docking

Glycosylation at C3-OH is the favorable modification for pharmaceutical activities and diversity expansion of 20(R)-dammarane ginsenosides. The 3-O-glycosylation, exclusively occurring in 20(R)-PPD ginsenosides, has never been achieved in 20(R)-PPT ginsenosides. Herein, 3-O-glycosylation of 20(R)-PPT enabled by a glycosyltransferase (GT) OsSGT2 was achieved with the combined assistance of AlphaFold 2 and molecular docking. Firstly, we combined AlphaFold2 algorithm and molecular docking to predict interactions between 20(R)-PPT and candidate GTs. A catalytically favorable binding geometry was thus identified in the OsSGT2-20(R)-PPT complex, suggesting OsSGT2 might act on 20(R)-PPT. The enzymatic assays demonstrated that OsSGT2 reacted with varied sugar donors to form 20(R)-PPT 3-O-glycosides, exhibiting donor promiscuity. Additionally, OsSGT2 displayed acceptor promiscuity, catalyzing 3-O-glucosylation of 20(R/S)-PPT, 20(R/S)-PPD and 20(R/S)-Rh1, respectively. Protein engineering on OsSGT2 was thus performed to probe its catalytic mechanism underlying its stereoselectivity. The W207A mutant preferred 20(S)-dammarane aglycons, while F395Q/A396G(QG) displayed a conversion enhancement towards both 20(R/S)-dammarane aglycons. The QG mutant was then used to synthesize 20(R)-PPT 3-O-glucoside, which displayed a moderate angiotensin-converting enzyme inhibitory effect with an IC50 of 27.5 ± 4.7 μM, superior to that of its 20(S)-epimer, with the combined assistance of target fishing and reverse docking. The water solubility of 20(R)-PPT 3-O-glucoside increased as well.

Retinal cell-targeted liposomal ginsenoside Rg3 attenuates retinal ischemia-reperfusion injury via alleviating oxidative stress and promoting microglia/macrophage M2 polarization

Retinal ischemia-reperfusion (RIR) injury remains a major challenge that is detrimental to retinal cell survival in a variety of ocular diseases. However, current clinical treatments focus on a single pathological mechanism, making them unable to provide comprehensive retinal protection. A variety of natural products including ginsenoside Rg3 (Rg3) exhibit potent antioxidant and anti-inflammatory activities. Unfortunately, the hydrophobicity of Rg3 and the presence of various intraocular barriers limit its effective application in clinical settings. Hyaluronic acid (HA)- specifically binds to cell surface receptors, CD44, which is widely expressed in retinal pigment epithelial cells and M1-type macrophage. Here, we developed HA-decorated liposomes loaded with Rg3, termed Rg3@HA-Lips, to protect against retinal damage caused by RIR injury. Treatment with Rg3@HA-Lips significantly inhibited the oxidative stress induced by RIR injury. In addition, Rg3@HA-Lips promoted the transition of M1-type macrophage to the M2 type, ultimately reversing the pro-inflammatory microenvironment. The mechanism of Rg3@HA-Lips was further investigated and found that they can regulateSIRT/FOXO3a, NF-κB and STAT3 signaling pathways. Together with as well demonstrated good safety profiles, this CD44-targeted platform loaded with a natural product alleviates RIR injury by modulating the retinal microenvironment and present a potential clinical treatment strategy.

Phytochemicals targeting lncRNAs: A novel direction for neuroprotection in neurological disorders

Neurological disorders with various etiologies impacting the nervous system are prevalent in clinical practice. Long non-coding RNA (lncRNA) molecules are functional RNA molecules exceeding 200 nucleotides in length that do not encode proteins, but participate in essential activities. Research indicates that lncRNAs may contribute to the pathogenesis of neurological disorders, and may be potential targets for their treatment. Phytochemicals in traditional Chinese herbal medicine (CHM) have been found to exert neuroprotective effects by targeting lncRNAs and regulating gene expression and various signaling pathways. We aim to establish the development status and neuroprotective mechanism of phytochemicals that target lncRNAs through a thorough literature review. A total of 369 articles were retrieved through manual and electronic searches of PubMed, Web of Science, Scopus and CNKI databases from inception to September 2022. The search utilized combinations of natural products, lncRNAs, neurological disorders, and neuroprotective effects as keywords. The included studies, a total of 31 preclinical trials, were critically reviewed to present the current situation and the progress in phytochemical-targeted lncRNAs in neuroprotection. Phytochemicals have demonstrated neuroprotective effects in preclinical studies of various neurological disorders by regulating lncRNAs. These disorders include arteriosclerotic ischemia-reperfusion injury, ischemic/hemorrhagic stroke, Alzheimer's disease, Parkinson's disease, glioma, peripheral nerve injury, post-stroke depression, and depression. Several phytochemicals exert neuroprotective roles through mechanisms such as anti-inflammatory, antioxidant, anti-apoptosis, autophagy regulation, and antagonism of Aβ-induced neurotoxicity. Some phytochemicals targeted lncRNAs and served a neuroprotective role by regulating microRNA and mRNA expression. The emergence of lncRNAs as pathological regulators provides a novel direction for the study of phytochemicals in CHM. Elucidating the mechanism of phytochemicals regulating lncRNAs will help to identify new therapeutic targets and promote their application in precision medicine.

A Review of Neuroprotective Effects and Mechanisms of Ginsenosides From Panax Ginseng in Treating Ischemic Stroke

Ischemic stroke has been considered one of the leading causes of mortality and disability worldwide, associated with a series of complex pathophysiological processes. However, effective therapeutic methods for ischemic stroke are still limited. Panax ginseng, a valuable traditional Chinese medicine, has been long used in eastern countries for various diseases. Ginsenosides, the main active ingredient of Panax ginseng, has demonstrated neuroprotective effects on ischemic stroke injury during the last decade. In this article, we summarized the pathophysiology of ischemic stroke and reviewed the literature on ginsenosides studies in preclinical and clinical ischemic stroke. Available findings showed that both major ginsenosides and minor ginsenosides (such as Rg3, Rg5, and Rh2) has a potential neuroprotective effect, mainly through attenuating the excitotoxicity, Ca²⁺ overload, mitochondria dysfunction, blood-brain barrier (BBB) permeability, anti-inflammation, anti-oxidative, anti-apoptosis, anti-pyroptosis, anti-autophagy, improving angiogenesis, and neurogenesis. Therefore, this review brings a current understanding of the mechanisms of ginsenosides in the treatment of ischemic stroke. Further studies, especially in clinical trials, will be important to confirm the clinical value of ginseng and ginsenosides.