The Role of The Gut Microbiome in Parkinson's Disease

The gut microbiota is known to play a role in various disease states through inflammatory, immune and endocrinologic response. Parkinson's Disease is of particular interest as gastrointestinal involvement is one of the earlier features seen in this disease. This paper examines the relationship between gut microbiota and Parkinson's Disease, which has a growing body of literature. Inflammation caused by gut dysbiosis is thought to increase a-synuclein aggregation and worsen motor and neurologic symptoms of Parkinson's disease. We discuss potential treatment and supplementation to modify the microbiota. Some of these treatments require further research before recommendations can be made, such as cord blood transplant, antibiotic use, immunomodulation and fecal microbiota transplant. Other interventions, such as increasing dietary fiber, polyphenol and fermented food intake, can be made with few risks and may have some benefit for symptom relief and speed of disease progression.

The metal cofactor zinc and interacting membranes modulate SOD1 conformation-aggregation landscape in an in vitro ALS model

Aggregation of Cu-Zn superoxide dismutase (SOD1) is implicated in the motor neuron disease, amyotrophic lateral sclerosis (ALS). Although more than 140 disease mutations of SOD1 are available, their stability or aggregation behaviors in membrane environment are not correlated with disease pathophysiology. Here, we use multiple mutational variants of SOD1 to show that the absence of Zn, and not Cu, significantly impacts membrane attachment of SOD1 through two loop regions facilitating aggregation driven by lipid-induced conformational changes. These loop regions influence both the primary (through Cu intake) and the gain of function (through aggregation) of SOD1 presumably through a shared conformational landscape. Combining experimental and theoretical frameworks using representative ALS disease mutants, we develop a 'co-factor derived membrane association model' wherein mutational stress closer to the Zn (but not to the Cu) pocket is responsible for membrane association-mediated toxic aggregation and survival time scale after ALS diagnosis.

Chemical Pathology of Homocysteine VIII. Effects of Tocotrienol, Geranylgeraniol, and Squalene on Thioretinaco Ozonide, Mitochondrial Permeability, and Oxidative Phosphorylation in Arteriosclerosis, Cancer, Neurodegeneration and Aging

A century ago a fat-soluble vitamin from leafy vegetables, later named vitamin E, was discovered to enhance fertility in animals. Vitamin E consists of 8 isomers of tocopherols and tocotrienols, each containing chromanol groups that confer antioxidant properties and differ only in the 15-carbon saturated phytyl poly-isoprenoid side chain of tocopherols and the 15-carbon unsaturated farnesyl poly-isoprenoid side chain of tocotrienols. Although tocotrienol was first isolated from rubber plants in 1964, its importance in multiple disease processes was not recognized until two decades later, when the cholesterol-lowering and anti-cancer effects were first reported. Tocotrienol (T3) protects against radiation injury and mitochondrial dysfunction by preventing opening of the mitochondrial permeability transition pore, thereby inhibiting loss of the active site for oxidative phosphorylation, thioretinaco ozonide oxygen ATP, from mitochondria by complex formation with the active site, TR₂CoO₃O₂NAD⁺H₂PO₄ ^-T3. The preventive effects of tocotrienol on vascular disease, cancer, neurodegeneration and aging are attributed to its effects on cellular apoptosis and senescence. Geranylgeraniol is an important intermediate in the biosynthesis of cholesterol, and cholesterol auxotrophy of lymphoma cell lines and primary tumors is attributed to loss of squalene monooxygenase and accumulation of intracellular squalene. Geranylgeraniol and tocotrienol have synergistic inhibitory effects on growth and HMG CoA reductase activity, accompanied by reduction of membrane KRAS protein of cultured human prostate carcinoma cells. Since cholesterol inhibits opening of the mPTP pore of mitochondria, inhibition of cholesterol biosynthesis by these effects of tocotrienol and geranylgeraniol produces increased mitochondrial dysfunction and apoptosis from loss of the active site of oxidative phosphorylation from mitochondria.

Vitamin D in Neurological Diseases: A Rationale for a Pathogenic Impact

It is widely known that vitamin D receptors have been found in neurons and glial cells, and their highest expression is in the hippocampus, hypothalamus, thalamus and subcortical grey nuclei, and substantia nigra. Vitamin D helps the regulation of neurotrophin, neural differentiation, and maturation, through the control operation of growing factors synthesis (i.e., neural growth factor [NGF] and glial cell line-derived growth factor (GDNF), the trafficking of the septohippocampal pathway, and the control of the synthesis process of different neuromodulators (such as acetylcholine [Ach], dopamine [DA], and gamma-aminobutyric [GABA]). Based on these assumptions, we have written this review to summarize the potential role of vitamin D in neurological pathologies. This work could be titanic and the results might have been very fuzzy and even incoherent had we not conjectured to taper our first intentions and devoted our interests towards three mainstreams, demyelinating pathologies, vascular syndromes, and neurodegeneration. As a result of the lack of useful therapeutic options, apart from the disease-modifying strategies, the role of different risk factors should be investigated in neurology, as their correction may lead to the improvement of the cerebral conditions. We have explored the relationships between the gene-environmental influence and long-term vitamin D deficiency, as a risk factor for the development of different types of neurological disorders, along with the role and the rationale of therapeutic trials with vitamin D implementation.

Emerging Roles of Astrocytes in Neuro-Vascular Unit and the Tripartite Synapse With Emphasis on Reactive Gliosis in the Context of Alzheimer's Disease

Astrocytes, which are five-fold more numerous than neurons in the central nervous system (CNS), are traditionally viewed to provide simple structural and nutritional supports for neurons and to participate in the composition of the blood brain barrier (BBB). In recent years, the active roles of astrocytes in regulating cerebral blood flow (CBF) and in maintaining the homeostasis of the tripartite synapse have attracted increasing attention. More importantly, astrocytes have been associated with the pathogenesis of Alzheimer's disease (AD), a major cause of dementia in the elderly. Although microglia-induced inflammation is considered important in the development and progression of AD, inflammation attributable to astrogliosis may also play crucial roles. A1 reactive astrocytes induced by inflammatory stimuli might be harmful by up-regulating several classical complement cascade genes thereby leading to chronic inflammation, while A2 induced by ischemia might be protective by up-regulating several neurotrophic factors. Here we provide a concise review of the emerging roles of astrocytes in the homeostasis maintenance of the neuro-vascular unit (NVU) and the tripartite synapse with emphasis on reactive astrogliosis in the context of AD, so as to pave the way for further research in this area, and to search for potential therapeutic targets of AD.

SCYL pseudokinases in neuronal function and survival

The generation of mice lacking SCYL1 or SCYL2 and the identification of Scyl1 as the causative gene in the motor neuron disease mouse model muscle deficient (Scyl1^mdf/mdf) demonstrated the importance of the SCY1-like family of protein pseudokinases in neuronal function and survival. Several essential cellular processes such as intracellular trafficking and nuclear tRNA export are thought to be regulated by SCYL proteins. However, whether deregulation of these processes contributes to the neurodegenerative processes associated with the loss of SCYL proteins is still unclear. Here, I briefly review the evidence supporting that SCYL proteins play a role in these processes and discuss their possible involvement in the neuronal functions of SCYL proteins. I also propose ways to determine the importance of these pathways for the functions of SCYL proteins in vivo.

Sensing risk, fearing uncertainty: systems science approach to change

Background: Medicine devotes its primary focus to understanding change, from cells to network relationships; observations of non-linearity are inescapable. Recent events provide extraordinary examples of major non-linear surprises within the societal system: human genome-from anticipated 100,000+ genes to only 20,000+; junk DNA-initially ignored but now proven to control genetic processes; economic reversals-bursting of bubbles in technology, housing, finance; foreign wars; relentless rise in obesity, neurodegenerative diseases. There are two attributes of systems science that are especially relevant to this research: One—it offers a method for creating a structural context with a guiding path to pragmatic knowledge; and, two—it gives pre-eminence to sensory input capable to register, evaluate, and react to change.

Materials/Methods: Public domain records of change, during the last 50 years, have been studied in the context of systems science, the dynamic systems model, and various cycles.

Results/Conclusions:Change is dynamic, ever-present, never isolated, and of variable impact; it reflects innumerable relationships among contextual systems; change can be perceived as risk or uncertainty depending upon how the assessment is made; risk is quantifiable by sensory input and generates a degree of rational optimism; uncertainty is not quantifiable and evokes fear; trust is key to sharing risk; the measurable financial credit can be a proxy for societal trust; expanding credit dilutes trust; when a credit bubble bursts, so will trust; absence of trust paralyzes systems' relationships leading to disorganized complexity which prevents value creation and heightens the probability of random events; disappearance of value, accompanied by chaos, threatens all systems. From personal health to economic sustainability and collective rationality, most examined components of the societal system were found not to be optimized and trust was not in evidence.

RNA pathogenesis via Toll-like receptor-activated inflammation in expanded repeat neurodegenerative diseases

Previously, we hypothesized that an RNA-based pathogenic pathway has a causal role in the dominantly inherited unstable expanded repeat neurodegenerative diseases. In support of this hypothesis we, and others, have characterized rCAG.rCUG₁₀₀ repeat double-strand RNA (dsRNA) as a previously unidentified agent capable of causing pathogenesis in a Drosophila model of neurodegenerative disease. Dicer, Toll, and autophagy pathways have distinct roles in this Drosophila dsRNA pathology. Dicer dependence is accompanied by cleavage of rCAG.rCUG₁₀₀ repeat dsRNA down to r(CAG)₇ 21-mers. Among the “molecular hallmarks” of this pathway that have been identified in Drosophila, some [i.e., r(CAG)₇ and elevated tumor necrosis factor] correlate with observations in affected people (e.g., Huntington’s disease and amyotrophic lateral sclerosis) or in related animal models (i.e., autophagy). The Toll pathway is activated in the presence of repeat-containing dsRNA and toxicity is also dependent on this pathway. How might the endogenously expressed dsRNA mediate Toll-dependent toxicity in neuronal cells? Endogenous RNAs are normally shielded from Toll pathway activation as part of the mechanism to distinguish “self” from “non-self” RNAs. This typically involves post-transcriptional modification of the RNA. Therefore, it is likely that rCAG.rCUG₁₀₀ repeat dsRNA has a characteristic property that interferes with or evades this normal mechanism of shielding. We predict that repeat expansion leads to an alteration in RNA structure and/or form that perturbs RNA modification, causing the unshielded repeat RNA (in the form of its Dicer-cleaved products) to be recognized by Toll-like receptors (TLRs), with consequent activation of the Toll pathway leading to loss of cell function and then ultimately cell death. We hypothesize that the proximal cause of expanded repeat neurodegenerative diseases is the TLR recognition (and resultant innate inflammatory response) of repeat RNA as “non-self” due to their paucity of “self” modification.

Recombinant Human Erythropoietin: Novel Strategies for Neuroprotective/Neuro-regenerative Treatment of Multiple Sclerosis

Treatment of multiple sclerosis (MS) is still unsatisfactory and essentially non-existing for the progressive course of the disease. Recombinant human erythropoietin (EPO) may be a promising neuroprotective/neuroregenerative treatment of MS. In the nervous system, EPO acts anti-apoptotic, antioxidative, anti-inflammatory, neurotrophic and plasticity-modulating. Beneficial effects have been shown in animal models of various neurological and psychiatric diseases, including different models of experimental autoimmune encephalomyelitis. EPO is also effective in human brain disease, as shown in double-blind placebo-controlled clinical studies on ischemic stroke and chronic schizophrenia. An exploratory study on chronic progressive MS yielded lasting improvement in motor and cognitive performance upon high-dose long-term EPO treatment.