A rationally designed microbial consortium modulates neurodegeneration in a Drosophila melanogaster model of Parkinson's disease.

MicroRNAs (miRNA) are small noncoding RNAs that play a significant role in the regulation of gene expression. The literature has explored the key involvement of miRNAs in the diagnosis, prognosis, and treatment of various neurodegenerative diseases (NDD), such as Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD). The miRNA regulates various signalling pathways; its dysregulation is involved in the pathogenesis of NDD. The present review is focused on the involvement of miRNAs in the pathogenesis of NDD and their role in the treatment or management of NDD. The literature provides comprehensive and cutting-edge knowledge for students studying neurology, researchers, clinical psychologists, practitioners, pathologists, and drug development agencies to comprehend the role of miRNAs in the NDD's pathogenesis, regulation of various genes/signalling pathways, such as α-synuclein, P53, amyloid-β, high mobility group protein (HMGB1), and IL-1β, NMDA receptor signalling, cholinergic signalling, etc. Methods: The issues associated with using anti-miRNA therapy are also summarized in this review. The data for this literature were extracted and summarized using various search engines, such as Google Scholar, Pubmed, Scopus, and NCBI using different terms, such as NDD, PD, AD, HD, nanoformulations of mRNA, and role of miRNA in diagnosis and treatment. The miRNAs control various biological actions, such as neuronal differentiation, synaptic plasticity, cytoprotection, neuroinflammation, oxidative stress, apoptosis and chaperone-mediated autophagy, and neurite growth in the central nervous system and diagnosis. Various miRNAs are involved in the regulation of protein aggregation in PD and modulating β-secretase activity in AD. In HD, mutation in the huntingtin (Htt) protein interferes with Ago1 and Ago2, thus affecting the miRNA biogenesis. Currently, many anti-sense technologies are in the research phase for either inhibiting or promoting the activity of miRNA. This review provides new therapeutic approaches and novel biomarkers for the diagnosis and prognosis of NDDs by using miRNA.

2021 Workshop: Neurodegenerative Diseases in the Gut-Brain Axis—Parkinson's Disease

Emerging non-invasive therapeutic approaches targeting hypocholinergic neural systems in Parkinson's disease.

This study aimed to investigate the effects of Levilactobacillus brevis, Lacticaseibacillus paracasei, and Lacticaseibacillus rhamnosus strains isolated from Mihalic cheese, also known as “weeping cheese”, on fermentation kinetics, microbial viability, and textural and aromatic properties of the butter matrix. The effects of the isolates were determined on acidification kinetics (Vmax, Tvmax, pHvmax), viability proportion index (VPI), textural parameters (firmness, work of shear, stickiness, work of adhesion), and volatile aroma compounds (GC-MS) formation. This study found that the BLR sample containing Lacticaseibacillus rhamnosus maintained its limited viability under acidic stress conditions despite its high fermentation rate and low pHvmax values. The BLP sample containing Lacticaseibacillus paracasei exhibited high viability due to its low acidification rate and limited pH change. Determining the chemical classes to which the aroma compounds in the BLP sample belonged revealed a composition rich in fatty acids. The BLB sample containing Levilactobacillus brevis produced a high ΔpH value and an aroma profile rich in aldehyde compounds. Examination of the macro-structural properties of the butter samples revealed that the sample containing Lacticaseibacillus rhamnosus, similar to the control sample (BMC), was more compact and rigid during storage. In contrast, samples containing Lacticaseibacillus paracasei and Levilactobacillus brevis had a softer/spreadable texture. These findings demonstrate the potential of lactic acid bacteria isolates from the traditional Mihalic cheese microbiota as biological catalysts for the development/improvement of texture, aroma, and sensory quality in high-fat dairy products and for the industrial production of products modified to meet consumer preferences.

The delivery of molecules and genes to the central nervous system (CNS) poses a major challenge for the treatment of neurodegenerative diseases. CNS disorders require long-term intervention and the presence of the blood-brain barrier (BBB) restricts the penetration of conventional drugs to the desired target cells. One approach towards stable delivery of therapeutic agents to the CNS is based on the transfer of DNA to target cells using viral vectors; a strategy known as gene therapy. Although viral vectors have provided encouraging results in CNS gene therapy trials for disorders such as Parkinson's disease, the small diffusion of the vector following direct injection into the brain region is not amenable to motor neuron (MN) disorders, such as amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy, that have cells distributed across fifty centimeters of spinal cord. The aim of this thesis was to explore non-invasive approaches for gene delivery to MNs of the spinal cord using adeno-associated viruses (AAV). AAV vectors are powerful gene transfer vehicles due to their low pathogenicity and ability to express genes in neurons for long periods of time. The first part of the thesis focused on ALS, an incurable paralytic disease resulting from a global death of MNs. Using a mouse model of ALS expressing a mutant form of superoxide dismutase 1 (SOD1) that causes the disease in humans, we have delivered genetic silencing instructions that act to degrade the SOD1 messenger RNA prior to its translation into the toxic protein. AAV serotype 6 was used to deliver the SOD1-silencing cassette through noninvasive peripheral routes to target relevant cell types in disease. The vector was administered intravenously following the hypothesis that AAV could infect MNs from the vasculature through traversing the peripheral axons that connect the MNs to the muscle fibers, a process known as retrograde transport. This resulted in infection of MNs across the spinal cord and brain stem, as well as almost total infection of skeletal muscle, another cell type implicated in ALS. Direct injections into multiple muscle groups were also performed, capitalizing on the retrograde transport capability of AAVs, to result in even higher levels of MN infection. These injections demonstrated that AAV serotype 6 could successfully deliver genes to MNs across the breadth of the spinal cord and resulted in protection of individual MN pools from ALS-mediated death. Curiously, however, despite the impressive infection profiles and neuroprotection at various spinal cord levels, neither of the techniques altered the disease course of the animals. These results stress the complexity of gene delivery and suggest that critical thresholds of SOD1-silencing and transduction across various cell types are required to rescue this particular disease model. The second component of the thesis concentrated purely on gene delivery to spinal cord neurons. AAV serotype 6 was injected directly into the muscles of Green African monkeys to determine whether the vector could undergo retrograde transport in larger animals. Indeed, efficient infection of MNs occurred, suggesting that this peripheral non-invasive delivery route is applicable to primates. These findings are not only relevant for human ALS therapy, but considering the similar dimensions of the injected monkeys with human newborns, directly relevant for treatment of infantile disease, spinal muscular atrophy. The last part of the thesis examined the ability of AAV serotype 6 to deliver genes to sensory neurons of spinal cord dorsal root ganglia in a mouse model of chronic pain. This study was initiated following the fortuitous observation of sensory neuron infection in the previous ALS mouse experiments. We examined various administration routes and found that AAV serotype 6 could efficiently deliver genes to sensory neurons in the context of chronic pain, demonstrating that the vector can be used to dissect mechanisms behind this disorder in rodents, and potentially serve as a vehicle for gene therapy towards intractable pain. In conclusion, the present thesis demonstrates that AAV serotype 6 is a powerful gene transfer vehicle for the CNS. Combined with future advances in AAV technology and delivery methods, the work presented here may one day facilitate gene therapy across the spinal cord for the treatment of devastating MN diseases, such as ALS and spinal muscular atrophy, as well as sensory neuron disorders, such as chronic pain.

Neuroinflammation, an inflammatory response within the central nervous system (CNS), is a main hallmark of common neurodegenerative diseases, including Alzheimer’s disease (AD), Parkinson’s disease (PD), and amyotrophic lateral sclerosis (ALS), among others. The over-activated microglia release pro-inflammatory cytokines, which induces neuronal death and accelerates neurodegeneration. Therefore, inhibition of microglia over-activation and microglia-mediated neuroinflammation has been a promising strategy for the treatment of neurodegenerative diseases. Many drugs have shown promising therapeutic effects on microglia and inflammation. However, the blood–brain barrier (BBB)—a natural barrier preventing brain tissue from contact with harmful plasma components—seriously hinders drug delivery to the microglial cells in CNS. As an emerging useful therapeutic tool in CNS-related diseases, nanoparticles (NPs) have been widely applied in biomedical fields for use in diagnosis, biosensing and drug delivery. Recently, many NPs have been reported to be useful vehicles for anti-inflammatory drugs across the BBB to inhibit the over-activation of microglia and neuroinflammation. Therefore, NPs with good biodegradability and biocompatibility have the potential to be developed as an effective and minimally invasive carrier to help other drugs cross the BBB or as a therapeutic agent for the treatment of neuroinflammation-mediated neurodegenerative diseases. In this review, we summarized various nanoparticles applied in CNS, and their mechanisms and effects in the modulation of inflammation responses in neurodegenerative diseases, providing insights and suggestions for the use of NPs in the treatment of neuroinflammation-related neurodegenerative diseases.

Glutamate-induced excito-neurotoxicity likely contributes to non-cell autonomous neuronal death in neurodegenerative diseases. Microglial clearance of dying neurons and associated debris is essential to maintain healthy neural networks in the central nervous system. In fact, the functions of microglia are regulated by various signaling molecules that are produced as neurons degenerate. Here, we show that the soluble CX3C chemokine fractalkine (sFKN), which is secreted from neurons that have been damaged by glutamate, promotes microglial phagocytosis of neuronal debris through release of milk fat globule-EGF factor 8, a mediator of apoptotic cell clearance. In addition, sFKN induces the expression of the antioxidant enzyme heme oxygenase-1 (HO-1) in microglia in the absence of neurotoxic molecule production, including NO, TNF, and glutamate. sFKN treatment of primary neuron-microglia co-cultures significantly attenuated glutamate-induced neuronal cell death. Using several specific MAPK inhibitors, we found that sFKN-induced heme oxygenase-1 expression was primarily mediated by activation of JNK and nuclear factor erythroid 2-related factor 2. These results suggest that sFKN secreted from glutamate-damaged neurons provides both phagocytotic and neuroprotective signals.

Neurodegenerative diseases (NDs) are a class of heterogeneous diseases that includes Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. Mitochondria play an important role in oxidative balance and metabolic activity of neurons; therefore, mitochondrial dysfunction is associated with NDs and mitochondria are considered a potential treatment target for NDs. Several obstacles, including the blood-brain barrier (BBB) and cell/mitochondrial membranes, reduce the efficiency of drug entry into the target lesions. Therefore, a variety of neuron mitochondrial targeting strategies has been developed. Among them, nanotechnology-based treatments show especially promising results. Owing to their adjustable size, appropriate charge, and lipophilic surface, nanoparticles (NPs) are the ideal theranostic system for crossing the BBB and targeting the neuronal mitochondria. In this review, we discussed the role of dysfunctional mitochondria in ND pathogenesis as well as the physiological barriers to various treatment strategies. We also reviewed the use and advantages of various NPs (including organic, inorganic, and biological membrane-coated NPs) for the treatment and diagnosis of NDs. Finally, we summarized the evidence and possible use for the promising role of NP-based theranostic systems in the treatment of mitochondrial dysfunction-related NDs.

Neurodegenerative diseases are global public health problems that seriously affect the quality of human life. The incidence of neurodegenerative diseases is increasing year by year and there has been no effective treatment. Acanthopanax senticosus is a Chinese medicine for tonifying kidney and has a long medicinal and edible history. It contains many active ingredients such as saponins, coumarins, flavonoids, organic acids and polysaccharides, with pharmacological effects of anti-oxidation, anti-age, anti-inflammation, anti-fatigue and immune regulation. Modern medical studies have found that A. senticosus can act on the central nervous system, and its extracts and active ingredients can improve learning and memory ability, playing vital roles of anti-oxidation, anti-inflammation, anti-apoptosis, antagonizing against amyloid β protein(Aβ) toxicity, modulating neurotransmitter release, signaling pathways and brain energy metabolism, maintaining the structure and function of mitochondria, and epigenetic regulation. It treats neurodegenerative diseases via multiple components, multiple targets, and multiple pathways, with the characteristics of low toxic side effects. This study reviewed the pharmacological reports of A. senticosus on neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease and ischemic stroke in China and abroad in recent ten years, and summarized the active ingredients and the mechanism underlying the neuroprotective effects of A. senticosus. Additionally, the significant advantages of A. senticosus in the treatment of neurodegenerative diseases and the limitations of the reports were discussed from the aspects of traditional Chinese medicine(TCM) theory and modern medical research. This study provided theoretical support for the drug development and clinical application of A. senticosus in treating neurodegenerative diseases and also facilitated the prevention and treatment of neurodegenerative diseases by kidney-tonifying method in TCM.

The aim of this study was to determine the effects of six common commercial lactic acid bacteria (LAB) additives [A1, Lactobacillus plantarum, L. buchneri, and Enterococcus faecalis; A2, L. plantarum and L. casei; A3, L. plantarum and L. buchneri; A4, L. plantarum, L. buchneri, L. casei, and Pediococcus acidilactici; A5, L. plantarum (producing feruloyl esterase); and A6, L. buchneri, P. acidilactici, β-glucanase, and xylanase] on the bacterial community and fermentation quality of alfalfa silage. Alfalfa was harvested at the squaring stage, wilted in the field for 24 h, and ensiled without any additives (Control) or with A1, A2, A3, A4, A5, or A6. Microbial counts, bacterial community, fermentation parameters, and nutritional composition were determined after ensiling for 90 days. The total abundance of LAB genera on alfalfa pre-ensiling was 0.38% in bacterial community. The abundances of Lactobacillus, Enterococcus, and Pediococcus in the Control silage were 42.18, 40.18, and 8.09% of abundance, respectively. The abundances of Lactobacillus in A1-, A2-, A3-, A4-, and A5-treatments were 89.32, 92.93, 92.87, 81.12, and 80.44%, respectively. The abundances of Pediococcus and Lactobacillus in A6-treatment were 70.14 and 24.86%, respectively. Compared with Control silage, LAB-treated silage had lower pH and less ammonia nitrogen and water-soluble carbohydrates concentrations (p < 0.05). Further, the A5- and A6-treatments contained lower neutral detergent fiber, acid detergent fiber, and hemicellulose than other treatments (p < 0.05). Overall, LAB genera were presented as minor taxa in alfalfa pre-ensiling and as dominant taxa in alfalfa silage. Adding LAB additives improved the fermentation quality and altered the bacterial community of alfalfa silage. The main bacterial genera in Control silage were Lactobacillus, Enterococcus, and Pediococcus. Lactobacillus dominated the bacterial communities of A1-, A2-, A3-, A4-, and A5-treatments, while Pediococcus and Lactobacillus were dominant bacterial genera in A6-treatment. Inoculating A5 and A6 degraded the fiber in alfalfa silage. It is necessary to ensile alfalfa with LAB inoculants.

A long-term use of chemical drugs cannot cure type II diabetes mellitus (T2DM) and their numerous toxic side effects can be harmful to human health. In recent years, probiotics have emerged as a natural resource to replace chemical drugs in alleviating many human ailments. Healthy children's intestines have a lot of colonized Lactobacilli and Bifidobacterium, and these beneficial bacteria can help promote overall health. The objective of this study was to isolate potential antidiabetic probiotic strains from healthy children and evaluate their application prospects. Firstly, Lactobacillus and Bifidobacterium strains were isolated from healthy children's feces and identified by the pheS or clpC genes with their respective 16S rRNA genes. Then, hydrophobicity, artificial gastrointestinal fluid tolerance, α-Glucosidase and Dipeptidyl peptidase IV (DPP-IV) inhibitory activities of isolated strains were determined, and antioxidant activities and promoting secretion of GLP-1 in STC-1 cells of candidate strains were tested. Results showed that 6 strains of Lactobacillus and Bifidobacterium were obtained from the feces of healthy children aged 3 years, respectively, including Lacticaseibacillus paracasei L-21 and L-25, Levilactobacillus brevis L-16, Lentilactobacillus buchneri L-9, Lactiplantibacillus plantarum L-8 and L-3, Bifidobacterium bifidum 11-1 and B-84, Bifidobacterium longum subsp. longum 6-1, 6-2, B42 and B53. The hydrophobicity and auto-aggregation levels of all these strains were higher than 30% and 50%, respectively, and the decrease in the number of colonies of all strains in the artificial gastrointestinal fluid was less than 2 log CFU/mL. Strains L-3, L-8, L-9, L-21, 6-1, 11-1, B53 and B84 were selected based on their high α-glucosidase inhibitory activity and DPP-IV inhibitory activity, and results of the antioxidant capacity assay showed that the remaining strains all had intense comprehensive antioxidant activity. Additionally, Lacticaseibacillus paracasei L-21 and Bifidobacterium longum subsp. longum B-53 had the most substantial prompting effect on GLP-1 secretion in the STC-1 cell line. These results indicated that Lacticaseibacillus paracasei L-21 and Bifidobacterium longum subsp. longum B-53 could be used as a potential antidiabetic strain; thus, its application as a food supplement and drug ingredient could be recommended after in vivo mitigation of type II diabetes test.

This study investigated the role of Lacticaseibacillus paracasei K-68 (LABK) and cocktail LAB (LABC) as silage inoculants to enhance corn silage fermentation quality and microbial stability. Silage spoilage is primarily caused by undesirable microbes such as Clostridium, Klebsiella, yeasts, and molds. The isolated LAB strain K-68 exhibited strong antibacterial and antifungal activity, particularly against spoilage organisms, and was identified as L. paracasei. Experimental silages inoculated with LABK or a LABC significantly improved fermentation profiles, with reduced pH and increased lactic acid levels. Microbial counts revealed that LAB-inoculated silages had higher LAB counts and significantly reduced yeast and mold populations. Furthermore, there were no significant differences in acetic acid, isobutyric acid, and propionic acid levels. High-throughput sequencing confirmed that LABK-treated silage was dominated by Lacticaseibacillus paracasei, whereas LABC-treated silage supported more diverse microbiota, including Pediococcus pentosaceus, Lacrimispora xylanolytica, and Levilactobacillus brevis. Both treatments suppressed spoilage-associated genera such as Clostridium and Klebsiella. Furthermore, correlation analysis showed that Lacticaseibacillus abundance was positively associated with lactic acid production and negatively correlated with pH and yeast levels. L. paracasei K-68 is a promising bio-inoculant for corn silage production since it promotes beneficial microbial dominance and suppresses spoilage organisms better than cocktail LAB.

A genome-scale metabolic model (GEM) represents metabolic pathways of an organism in a mathematical form and can be built using biochemistry and genome annotation data. GEMs are invaluable for understanding organisms since they analyze the metabolic capabilities and behaviors quantitatively and can predict phenotypes. The development of high-throughput data collection techniques led to an immense increase in omics data such as metagenomics, which expand our knowledge on the human microbiome, but this also created a need for systematic analysis of these data. In recent years, GEMs have also been reconstructed for microbial species, including human gut microbiota, and methods for the analysis of microbial communities have been developed to examine the interaction between the organisms or the host. The purpose of this review is to provide a comprehensive guide for the applications of GEMs in microbial community analysis. Starting with GEM repositories, automatic GEM reconstruction tools, and quality control of models, this review will give insights into microbe-microbe and microbe-host interaction predictions and optimization of microbial community models. Recent studies that utilize microbial GEMs and personalized models to infer the influence of microbiota on human diseases such as inflammatory bowel diseases (IBD) or Parkinson's disease are exemplified. Being powerful system biology tools for both species-level and community-level analysis of microbes, GEMs integrated with omics data and machine learning techniques will be indispensable for studying the microbiome and their effects on human physiology as well as for deciphering the mechanisms behind human diseases.

Impairment of "protein quality control" in neurons is associated with etiopathogenesis of neurodegenerative diseases. The worn-out products of cell metabolism should be safely eliminated via the proteasome, autophago-lysosome and exocytosis. Insufficient activity of these degradation mechanisms within neurons leads to the accumulation of toxic protein oligomers, which represent a starting material for development of neurodegenerative proteinopathy. The spectrum of CNS linked proteinopathies is particularly broad and includes Alzheimer's disease (AD), Parkinson's disease (PD), Lewy body dementia, Pick disease, Frontotemporal dementia, Huntington disease, Amyotrophic lateral sclerosis and many others. Although the primary events in etiopathogenesis of sporadic forms of these diseases are still unknown, it is clear that aging, in connection with decreased activity of ubiquitin proteasome system, is the most significant risk factor. In this review we discuss the pathogenic role and intracellular fate of the candidate molecules associated with onset and progression of AD and PD, the protein tau and α-synuclein in context with the function of ubiquitin proteasome system. We also discuss the possibility whether or not the strategies focused to re-establishment of neuroproteostasis via accelerated clearance of damaged proteins in proteasome could be a promising therapeutic approach for treatment of major neurodegenerative diseases.

Neuroinflammation, characterised by an overactive immune system in the brain and spinal cord, has now been tied to several neurodegenerative diseases. Here, immune cells invade into the brain, activating astrocytes and microglia. Neuroinflammation is a common symptom of many neurodegenerative illnesses, including Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS). This inflammatory reaction occurs within the central nervous system (CNS). Neurological dysfunction results from the inflammatory response, which arises in reaction to any kind of brain injury. Regulating neuroinflammation can be useful for controlling brain disorders associated with neuroinflammation. Several targeted drug delivery systems attempt to treat neuroinflammation caused by neurodegenerative illnesses or brain tumours by targeting the microglia and other immune cells in the central nervous system. Therefore, biodegradable and biocompatible NPs (nanoparticles) could be developed as a treatment for neurodegenerative diseases caused by neuroinflammation or as a less invasive means of transporting other drugs across the blood-brain barrier. Numerous applications of gold nanoparticles (AuNPs) in the treatment of neurological diseases, including Alzheimer's disease (AD) and Parkinson's disease (PD), are studied in this article. To prevent neuroinflammation and microglia over-activation, some NPs have recently been found to be effective anti-inflammatory medication carriers that cross the blood-brain barrier.