Total astragalosides promote oligodendrocyte precursor cell differentiation and enhance remyelination in cuprizone-induced mice through suppression of Wnt/β-catenin signaling pathway

Antidepressant potential of total flavonoids from Astragalus in a chronic stress mouse model: Implications for myelination and Wnt/β-catenin/Olig2/Sox10 signaling axis modulation

ETHNOPHARMACOLOGICAL RELEVANCE

Radix Astragali, a versatile traditional Chinese medicinal herb, has a rich history dating back to "Sheng Nong's herbal classic". It has been employed in clinical practice to address various ailments, including depression. One of its primary active components, total flavonoids from Astragalus (TFA), remains unexplored in terms of its potential antidepressant properties. This study delves into the antidepressant effects of TFA using a mouse model subjected to chronic unpredictable mild stress (CUMS).

AIMS OF THE STUDY

The study aimed to scrutinize how TFA influenced depressive behaviors, corticosterone and glutamate levels in the hippocampus, as well as myelin-related protein expression in CUMS mice. Additionally, it sought to explore the involvement of the Wnt/β-catenin/Olig2/Sox10 signaling axis as a potential antidepressant mechanism of TFA.

MATERIALS AND METHODS

Male C57BL/6 mice were subjected to CUMS to induce depressive behaviors. TFA were orally administered at two different doses (50 mg/kg and 100 mg/kg). A battery of behavioral tests, biochemical analyses, immunohistochemistry, UPLC-MS/MS, real-time PCR, and Western blotting were employed to evaluate the antidepressant potential of TFA. The role of the Wnt/β-catenin/Olig2/Sox10 signaling axis in the antidepressant mechanism of TFA was validated through MO3.13 cells.

RESULTS

TFA administration significantly alleviated depressive behaviors in CUMS mice, as evidenced by improved sucrose preference, reduced immobility in tail suspension and forced swimming tests, and increased locomotor activity in the open field test. Moreover, TFA effectively reduced hippocampal corticosterone and glutamate levels and promoted myelin formation in the hippocampus of CUMS mice. Then, TFA increased Olig2 and Sox10 expression while inhibiting the Wnt/β-catenin pathway in the hippocampus of CUMS mice. Finally, we further confirmed the role of TFA in promoting myelin regeneration through the Wnt/β-catenin/Olig2/Sox10 signaling axis in MO3.13 cells.

CONCLUSIONS

TFA exhibited promising antidepressant effects in the CUMS mouse model, facilitated by the restoration of myelin sheaths and regulation of corticosterone, glutamate, Olig2, Sox10, and the Wnt/β-catenin pathway. This research provides valuable insights into the potential therapeutic application of TFA in treating depression, although further investigations are required to fully elucidate the underlying molecular mechanisms and clinical relevance.

Oligodendrocytes Play a Critical Role in White Matter Damage of Vascular Dementia

With the deepening of population aging, the treatment of cognitive impairment and dementia is facing increasing challenges. Vascular dementia (VaD) is a cognitive dysfunction caused by brain blood flow damage and one of the most common causes of dementia after Alzheimer's disease. White matter damage in patients with chronic ischemic dementia often occurs before cognitive impairment, and its pathological changes include leukoaraiosis, myelin destruction and oligodendrocyte death. The pathophysiology of vascular dementia is complex, involving a variety of neuronal and vascular lesions. The current proposed mechanisms include calcium overload, oxidative stress, nitrative stress and inflammatory damage, which can lead to hypoxia-ischemia and demyelination. Oligodendrocytes are the only myelinating cells in the central nervous system and closely associated with VaD. In this review article, we intend to further discuss the role of oligodendrocytes in white matter and myelin injury in VaD and the development of anti-myelin injury target drugs.

Natural compounds as potential therapeutic candidates for multiple sclerosis: Emerging preclinical evidence

BACKGROUND

Multiple sclerosis is a chronic neurodegenerative disease, with main characteristics of pathological inflammation, neural damage and axonal demyelination. Current mainstream treatments demonstrate more or less side effects, which limit their extensive use.

PURPOSE

Increasing studies indicate that natural compounds benefit multiple sclerosis without remarkable side effects. Given the needs to explore the potential effects of natural compounds of plant origin on multiple sclerosis and their mechanisms, we review publications involving the role of natural compounds in animal models of multiple sclerosis, excluding controlled trials.

STUDY DESIGN AND METHODS

Articles were conducted on PubMed and Web of Science databases using the keywords ``multiple sclerosis'' and ``natural compounds'' published from January 1, 2008, to September 1, 2023.

RESULTS

This review summarized the effects of natural ingredients (flavonoids, terpenoids, polyphenols, alkaloids, glycosides, and others) from three aspects: immune regulation, oxidative stress suppression, and myelin protection and regeneration in multiple sclerosis.

CONCLUSION

Overall, we concluded 80 studies to show the preclinical evidence that natural compounds may attenuate multiple sclerosis progression via suppressing immune attacks and/or promoting myelin protection or endogenous repair processes. It would pave the roads for the future development of effective therapeutic regiments of multiple sclerosis.

Sanwei DouKou Decoction ameliorate Alzheimer disease by increasing endogenous neural stem cells proliferation through the Wnt/β-catenin signalling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Sanwei DouKou decoction (SDKD) is a traditional Chinese medicine (TCM) prescription derived from the Tibetan medical book "Si Bu Yi Dian" and is clinically used for the treatment of Alzheimer's disease (AD). However, the potential mechanism of SDKD treatment for AD remains elusive.

AIM OF THE STUDY

This study aims to explore the potential mechanism by which SDKD alleviates AD.

MATERIALS AND METHODS

Extracts of SDKD were identified with Gas chromatograph-mass spectrometer (GC-MS). 5 × FAD mice were treated with SDKD for 8 weeks. The efficacy of SDKD against AD was evaluated by in-vivo experiments. Morris water maze and contextual fear conditioning tests were used to detect the learning and memory ability of mice. Hematoxylin-eosin staining (H&E) staining was used to observe the pathological changes of brain tissue. Immunohistochemistry was used to detect the positive expression of Nestin in hippocampus. In in-vitro experiments, the Cell Counting Kit 8 (CCK-8) technique was used to detect cell viability, the proliferation of neural stem cells was detected by immunofluorescence staining, the intracellular protein expression was detected by Western Blot.

RESULTS

The results of this study suggested that SDKD may ameliorate AD. SDKD significantly shortened the escape latency of mice in the Morris water maze experiment, increased the number of times the mice crossed the target quadrant, and prolonged freezing time in the contextual fear memory experiment. SDKD also improved neuronal pathology in the hippocampus, decreased neuronal loss, and increased Nestin protein levels. Furthermore, in in-vitro experiments, SDKD could significantly increase Neural stem cells (NSCs) viability, promoted NSCs proliferation, and also effectively activated the Wnt/β-catenin signalling pathway, increased Wnt family member 3A (Wnt3a), β-catenin and CyclinD1 protein levels, activated the NSCs proliferation pathways in AD model mouse brain tissue.

CONCLUSIONS

The present study demonstrated that sanwei doukou decoction can ameliorate AD by increasing endogenous neural stem cells proliferation through the Wnt/β-catenin signalling pathway. Our observations justify the traditional use of SDKD for a treatment of AD in nervous system.

Mechanism of ERK/CREB pathway in pain and analgesia

Research has long centered on the pathophysiology of pain. The Transient Receiver Potential (TRP) protein family is well known for its function in the pathophysiology of pain, and extensive study has been done in this area. One of the significant mechanisms of pain etiology and analgesia that lacks a systematic synthesis and review is the ERK/CREB (Extracellular Signal-Regulated Kinase/CAMP Response Element Binding Protein) pathway. The ERK/CREB pathway-targeting analgesics may also cause a variety of adverse effects that call for specialized medical care. In this review, we systematically compiled the mechanism of the ERK/CREB pathway in the process of pain and analgesia, as well as the potential adverse effects on the nervous system brought on by the inhibition of the ERK/CREB pathway in analgesic drugs, and we suggested the corresponding solutions.

Remyelination in Multiple Sclerosis: Findings in the Cuprizone Model

Remyelination therapies, which are currently under development, have a great potential to delay, prevent or even reverse disability in multiple sclerosis patients. Several models are available to study the effectiveness of novel compounds in vivo, among which is the cuprizone model. This model is characterized by toxin-induced demyelination, followed by endogenous remyelination after cessation of the intoxication. Due to its high reproducibility and ease of use, this model enjoys high popularity among various research and industrial groups. In this review article, we will summarize recent findings using this model and discuss the potential of some of the identified compounds to promote remyelination in multiple sclerosis patients.