Protective Effects of Polysaccharides in Neurodegenerative Diseases

Multiple Metabolites Derived from Mushrooms and Their Beneficial Effect on Alzheimer's Diseases

Mushrooms with edible and medicinal potential have received widespread attention because of their diverse biological functions, nutritional value, and delicious taste, which are closely related to their rich active components. To date, many bioactive substances have been identified and purified from mushrooms, including proteins, carbohydrates, phenols, and vitamins. More importantly, molecules derived from mushrooms show great potential to alleviate the pathological manifestations of Alzheimer's disease (AD), which seriously affects the health of elderly people. Compared with current therapeutic strategies aimed at symptomatic improvement, it is particularly important to identify natural products from resource-rich mushrooms that can modify the progression of AD. This review summarizes recent investigations of multiple constituents (carbohydrates, peptides, phenols, etc.) isolated from mushrooms to combat AD. In addition, the underlying molecular mechanisms of mushroom metabolites against AD are discussed. The various mechanisms involved in the antiAD activities of mushroom metabolites include antioxidant and anti-neuroinflammatory effects, apoptosis inhibition, and stimulation of neurite outgrowth, etc. This information will facilitate the application of mushroom-derived products in the treatment of AD. However, isolation of new metabolites from multiple types of mushrooms and further in vivo exploration of the molecular mechanisms underlying their antiAD effect are still required.

Polysaccharides Extracted from Dendrobium officinale Grown in Different Environments Elicit Varying Health Benefits in Caenorhabditis elegans

Dendrobium officinale is one of the most widely used medicinal herbs, especially in Asia. In recent times, the polysaccharide content of D. officinale has garnered attention due to the numerous reports of its medicinal properties, such as anticancer, antioxidant, anti-diabetic, hepatoprotective, neuroprotective, and anti-aging activities. However, few reports of its anti-aging potential are available. Due to high demand, the wild D. officinale is scarce; hence, alternative cultivation methods are being employed. In this study, we used the Caenorhabditis elegans model to investigate the anti-aging potential of polysaccharides extracted from D. officinale (DOP) grown in three different environments; tree (TR), greenhouse (GH), and rock (RK). Our findings showed that at 1000 µg/mL, GH-DOP optimally extended the mean lifespan by 14% and the maximum lifespan by 25% (p < 0.0001). TR-DOP and RK-DOP did not extend their lifespan at any of the concentrations tested. We further showed that 2000 µg/mL TR-DOP, GH-DOP, or RK-DOP all enhanced resistance to H₂O₂-induced stress (p > 0.05, p < 0.01, and p < 0.01, respectively). In contrast, only RK-DOP exhibited resistance (p < 0.01) to thermal stress. Overall, DOP from the three sources all increased HSP-4::GFP levels, indicating a boost in the ability of the worms to respond to ER-related stress. Similarly, DOP from all three sources decreased α-synuclein aggregation; however, only GH-DOP delayed β-amyloid-induced paralysis (p < 0.0001). Our findings provide useful information on the health benefits of DOP and also provide clues on the best practices for cultivating D. officinale for maximum medicinal applications.

Chemical and Biological Properties of Three Poorly Studied Species of Lycium Genus-Short Review

The genus Lycium belongs to the Solanaceae family and comprises more than 90 species distributed by diverse continents. Lycium barbarum is by far the most studied and has been advertised as a “superfood” with healthy properties. In contrast, there are some Lycium species which have been poorly studied, although used by native populations. L. europaeum, L. intricatum and L. schweinfurthii, found particularly in the Mediterranean region, are examples of scarcely investigated species. The chemical composition and the biological properties of these species were reviewed. The biological properties of L. barbarum fruits are mainly attributed to polysaccharides, particularly complex glycoproteins with different compositions. Studies regarding these metabolites are practically absent in L. europaeum, L. intricatum and L. schweinfurthii. The metabolites isolated and identified belong mainly to polyphenols, fatty acids, polysaccharides, carotenoids, sterols, terpenoids, tocopherols, and alkaloids (L. europaeum); phenolic acids, lignans, flavonoids, polyketides, glycosides, terpenoids, tyramine derivatives among other few compounds (L. schweinfurthii), and esters of phenolic acids, glycosides, fatty acids, terpenoids/phytosterols, among other few compounds (L. intricatum). The biological properties (antioxidant, anti-inflammatory and cytotoxic against some cancer cell lines) found for these species were attributed to some metabolites belonging to those compound groups. Results of the study concluded that investigations concerning L. europaeum, L. intricatum and L. schweinfurthii are scarce, in contrast to L. barbarum.

New Insights into the Gut Microbiota in Neurodegenerative Diseases from the Perspective of Redox Homeostasis

An imbalance between oxidants and antioxidants in the body can lead to oxidative stress, which is one of the major causes of neurodegenerative diseases. The gut microbiota contains trillions of beneficial bacteria that play an important role in maintaining redox homeostasis. In the last decade, the microbiota-gut-brain axis has emerged as a new field that has revolutionized the study of the pathology, diagnosis, and treatment of neurodegenerative diseases. Indeed, a growing number of studies have found that communication between the brain and the gut microbiota can be accomplished through the endocrine, immune, and nervous systems. Importantly, dysregulation of the gut microbiota has been strongly associated with the development of oxidative stress-mediated neurodegenerative diseases. Therefore, a deeper understanding of the relationship between the gut microbiota and redox homeostasis will help explain the pathogenesis of neurodegenerative diseases from a new perspective and provide a theoretical basis for proposing new therapeutic strategies for neurodegenerative diseases. In this review, we will describe the role of oxidative stress and the gut microbiota in neurodegenerative diseases and the underlying mechanisms by which the gut microbiota affects redox homeostasis in the brain, leading to neurodegenerative diseases. In addition, we will discuss the potential applications of maintaining redox homeostasis by modulating the gut microbiota to treat neurodegenerative diseases, which could open the door for new therapeutic approaches to combat neurodegenerative diseases.

Mushroom Polysaccharides as Potential Candidates for Alleviating Neurodegenerative Diseases

Neurodegenerative diseases (NDs) are a widespread and serious global public health burden, particularly among the older population. At present, effective therapies do not exist, despite the increasing understanding of the different mechanisms of NDs. In recent years, some drugs, such as galantamine, entacapone, riluzole, and edaravone, have been proposed for the treatment of different NDs; however, they mainly concentrate on symptom management and confer undesirable side effects and adverse reactions. Therefore, there is an urgent need to find novel drugs with fewer disadvantages and higher efficacy for the treatment of NDs. Mushroom polysaccharides are macromolecular complexes with multi-targeting bioactivities, low toxicity, and high safety. Some have been demonstrated to exhibit neuroprotective effects via their antioxidant, anti-amyloidogenic, anti-neuroinflammatory, anticholinesterase, anti-apoptotic, and anti-neurotoxicity activities, which have potential in the treatment of NDs. This review focuses on the different processes involved in ND development and progression, highlighting the neuroprotective activities and potential role of mushroom polysaccharides and summarizing the limitations and future perspectives of mushroom polysaccharides in the prevention and treatment of NDs.

Bibliometric analysis of research on Alzheimer’s disease and non-coding RNAs: Opportunities and challenges

Background

Non-coding RNAs (ncRNA) are a kind of RNA that does not encode protein, which play an important role in Alzheimer’s disease (AD). However, there is a lack of bibliometric analysis and visualization analysis of the research related to AD and ncRNAs.

Materials and methods

Literature related to AD and ncRNAs in the last decade were searched through the Web of Science Core Collection (WOSCC). The relevant information from all the searched articles was collected. The bibliometric visualization website, CiteSpace, and VOSviewer were used for visualization analysis of countries/regions, institutions, authors, and keywords.

Results

In total, 1,613 kinds of literature were published in the field. Literature in this field were published in 494 journals. The Journal of Alzheimer’s Disease was the most popular journal. China, Louisiana State University System, and Lukiw WJ were the countries/regions, institutions, and authors with the highest scientific productivity, respectively. The research hotspots in this field focused on the role and mechanism of ncRNAs, especially microRNAs, in AD. The level of research was mainly based on basic research, focusing on animal and cellular levels, and related to proteomics. “Circular RNAs,” “regulation of neuroinflammation,” and “tau protein” were the future research directions.

Conclusion

Taken together, the field of AD and ncRNAs is developing well. The research hotspots and frontiers in this field can provide a reference for researchers to choose their research direction.

Neuroinflammation: Molecular Mechanisms And Therapeutic Perspectives

BACKGROUND

Neuroinflammation is a key component in the etiopathogenesis of neurological diseases and brain aging. This process involves the brain immune system that modulates synaptic functions and protects neurons from infection or damage. Hence, the knowledge of neuroinflammation related pathways and modulation by drugs or natural compounds is functional to developing therapeutic strategies aimed at preserving, maintaining and restoring brain health.

OBJECTIVE

This review article summarizes the basics of neuroinflammation and related signaling pathways, the success of the dietary intervention in clinical practice and the possible development of RNA-based strategies for treating neurological diseases.

METHODS

Pubmed search from 2012 to 2022 with the keywords neuroinflammation and molecular mechanisms in combination with diet, miRNA and non-coding RNA.

RESULTS

Glial cells-play a crucial role in neuroinflammation, but several pathways can be activated in response to different inflammatory stimuli, inducing cell death by apoptosis, pyroptosis or necroptosis. The dietary intervention has immunomodulatory effects and could limit the inflammatory process induced by microglia and astrocytes. Thus by inhibiting neuroinflammation and improving the symptoms of a variety of neurological diseases, diet exerts pleiotropic neuroprotective effects independently from the spectrum of pathophysiological mechanisms underlying the specific disorder. Furthermore, data from animal models revealed that altered expression of specific noncoding RNAs, in particular microRNAs, contributes to neuroinflammatory diseases; consequently, RNA-based strategies may be promising to alleviate the consequences of neuroinflammation.

CONCLUSION

Further studies are needed to identify the molecular pathways and the new pharmacological targets in neuroinflammation to lay the basis for more effective and selective therapies to be applied, in parallel to dietary intervention, in the treatment of neuroinflammation-based diseases.