Phospholipids, Sphingolipids, and Cholesterol-Derived Lipid Mediators and Their Role in Neurological Disorders.

Neural membranes are composed of phospholipids, sphingolipids, cholesterol, and proteins. In response to cell stimulation or injury, the metabolism of lipids generates various lipid mediators, which perform many cellular functions. Thus, phospholipids release arachidonic acid or docosahexaenoic acid from the sn-2 position of the glycerol moiety by the action of phospholipases A.

COVID-19, Blood Lipid Changes, and Thrombosis.

Although there is increasing evidence that oxidative stress and inflammation induced by COVID-19 may contribute to increased risk and severity of thromboses, the underlying mechanism(s) remain to be understood. The purpose of this review is to highlight the role of blood lipids in association with thrombosis events observed in COVID-19 patients. Among different types of phospholipases A that target cell membrane phospholipids, there is increasing focus on the inflammatory secretory phospholipase A IIA (sPLA-IIA), which is associated with the severity of COVID-19.

Zika virus endemic challenges during COVID-19 pandemic in Africa.

Zika virus remains endemic and opportunistic of high transmission in the tropical region of Africa, and the repeated cases of the Zika virus in Africa made it public health emergency in 2016. Amidst the COVID-19 pandemic, the catastrophic cases of unknown and unreported deaths overwhelming the region of Africa could not give health attention to respond to other endemic diseases. Here, we present the possible complication and challenges associated with the Zika virus in Africa and COVID-19 predominance, shifting the attention from the Zika virus surveillance.

Ayurvedic Medicine for the Treatment of Dementia: Mechanistic Aspects.

Ayurvedic medicine is a personalized system of traditional medicine native to India and the Indian subcontinent. It is based on a holistic view of treatment which promotes and supports equilibrium in different aspects of human life: the body, mind, and soul. Popular Ayurvedic medicinal plants and formulations that are used to slow down brain aging and enhance memory include Ashwagandha , Turmeric , Brahmi , Shankhpushpi (, and other species), gotu kola , and guggulu ( and related species) and a formulation known as Brāhmī Ghita, containing Brahmi, Vacā , Kuha , Shankhpushpi, and Purāṇa Ghita (old clarified butter/old ghee).

Qi Fu Yin-a Ming Dynasty Prescription for the Treatment of Dementia.

The Traditional Chinese Medicine (TCM) theory that "kidneys give rise to marrow, and the brain is the sea of marrow" has been a guide for the clinical application of kidney, qi and blood tonics for prevention and treatment of dementia and improvement in memory. As low resistance end-organs, both the brain and the kidneys are subjected to blood flow of high volumes throughout the cardiac cycle. Alzheimer's disease and vascular dementia are two common causes of dementia, and it is increasingly recognized that many older adults with dementia have both AD and vascular pathologies.

A metabolism perspective on alternative urban water servicing options using water mass balance.

Urban areas will need to pursue new water servicing options to ensure local supply security. Decisions about how best to employ them are not straightforward due to multiple considerations and the potential for problem shifting among them. We hypothesise that urban water metabolism evaluation based a water mass balance can help address this, and explore the utility of this perspective and the new insights it provides about water servicing options.

Role of sphingomyelinases in neurological disorders.

Introduction: Sphingomyelinases, which catalyze the hydrolysis of sphingomyelin to ceramide and phosphorylcholine, are abundant in the brain. These enzymes are a major, rapid source of ceramide production not only during physiological responses to receptor stimulation, but also in neurological disorders.

Areas Covered: We covered an introduction to sphingomyelinases and its enzymatic product ceramide, in membrane domains or lipid rafts and the nucleus; followed by crosstalk between sphingomyelinase and cytosolic phospholipase A2 (cPLA2) catalysed products including arachidonic acid, functions of acid sphingomyelinase (aSMase) and neutral sphingomyelinase (N-SMase) in neurons, neuronal progenitor cells, glial cells, and brain endothelial cells; alterations in acid and N-SMases in Niemann Pick Disease Type A, major depression, Alzheimer's disease, cerebral ischemia, and pain; and recent developments in identification of inhibitors to sphingomyelinases.

Protective effects of ginseng on neurological disorders.

Ginseng (Order: Apiales, Family: Araliaceae, Genus: Panax) has been used as a traditional herbal medicine for over 2000 years, and is recorded to have antianxiety, antidepressant and cognition enhancing properties. The protective effects of ginseng on neurological disorders are discussed in this review. Ginseng species and ginsenosides, and their intestinal metabolism and bioavailability are briefly introduced.

Synthetic and natural inhibitors of phospholipases A2: their importance for understanding and treatment of neurological disorders.

Phospholipases A2 (PLA2) are a diverse group of enzymes that hydrolyze membrane phospholipids into arachidonic acid and lysophospholipids. Arachidonic acid is metabolized to eicosanoids (prostaglandins, leukotrienes, thromboxanes), and lysophospholipids are converted to platelet-activating factors. These lipid mediators play critical roles in the initiation, maintenance, and modulation of neuroinflammation and oxidative stress.

A potential link among biogenic amines-based pesticides, learning and memory, and colony collapse disorder: a unique hypothesis.

Pesticides are substances that have been widely used throughout the world to kill, repel, or control organisms such as certain forms of plants or animals considered as pests. Depending on their type, dose, and persistence in the environment, they can have impact even on non-target species such as beneficial insects (honeybees) in different ways, including reduction in their survival rate and interference with their reproduction process. Honeybee Apis mellifera is a major pollinator and has substantial economical and ecological values.

Beneficial effects of propolis on human health and neurological diseases.

Propolis is a natural product, collected by honeybees Apis mellifera, from various plant sources. Propolis is extensively used in foods and beverages because it improves human health. It contains more than 300 natural compounds such as polyphenols, phenolic aldehydes, sequiterpene-quinones, coumarins, amino acids, steroids and inorganic compounds.

Metabolic syndrome as a risk factor for neurological disorders.

The metabolic syndrome is a cluster of common pathologies: abdominal obesity linked to an excess of visceral fat, insulin resistance, dyslipidemia and hypertension. At the molecular level, metabolic syndrome is accompanied not only by dysregulation in the expression of adipokines (cytokines and chemokines), but also by alterations in levels of leptin, a peptide hormone released by white adipose tissue. These changes modulate immune response and inflammation that lead to alterations in the hypothalamic 'bodyweight/appetite/satiety set point,' resulting in the initiation and development of metabolic syndrome.

Glycerophospholipids and glycerophospholipid-derived lipid mediators: a complex meshwork in Alzheimer's disease pathology.

An increasing body of evidence suggested that intracellular lipid metabolism is dramatically perturbed in various cardiovascular and neurodegenerative diseases with genetic and lifestyle components (e.g., dietary factors).

Lipid-mediated oxidative stress and inflammation in the pathogenesis of Parkinson's disease.

Parkinson's disease (PD) is a neurodegenerative movement disorder of unknown etiology. PD is characterized by the progressive loss of dopaminergic neurons in the substantia nigra, depletion of dopamine in the striatum, abnormal mitochondrial and proteasomal functions, and accumulation of α-synuclein that may be closely associated with pathological and clinical abnormalities. Increasing evidence indicates that both oxidative stress and inflammation may play a fundamental role in the pathogenesis of PD.

Involvement of cytosolic phospholipase A(2), calcium independent phospholipase A(2) and plasmalogen selective phospholipase A(2) in neurodegenerative and neuropsychiatric conditions.

Enzymes belonging to the PLA(2) superfamily catalyze the hydrolysis of unsaturated fatty acids from the sn-2 position of glycerol moiety of neural membrane phospholipids. The PLA(2) superfamily is classified into cytosolic PLA(2) (cPLA(2)), calcium-independent PLA(2) (iPLA(2)), plasmalogen-selective PLA(2) (PlsEtn-PLA(2)) and secretory PLA(2) (sPLA(2)). PLA(2) paralogs/splice variants/isozymes are part of a complex signal transduction network that maintains cross-talk among excitatory amino acid and dopamine receptors through the generation of second messengers.

Lipid mediators in the nucleus: Their potential contribution to Alzheimer's disease.

Degradation of glycerophospholipids, sphingolipids and cholesterol in the nucleus modulates neural cell proliferation and differentiation, inflammation, apoptosis, migration, cell adhesion, and intracellular trafficking. Extracellular signals from agonists (neurotransmitters, cytokines, and growth factors) regulate the activity of a key set of lipid-metabolizing enzymes, such as phospholipases, sphingomyelinases, and cholesterol hydroxylases. These enzymes and their downstream targets constitute a complex lipid signaling network with multiple nodes of interaction and cross-regulation through their lipid mediators, which include eicosanoids, docosanoids, diacylglycerols, platelet activating factor, lysophosphatidic acid, ceramide and ceramide 1-phosphate, sphingosine and sphingosine 1-phosphate, and hydroxycholesterols.

Aging: an important factor for the pathogenesis of neurodegenerative diseases.

Aging is a natural process that is defined as a progressive deterioration of biological functions after the organism has attained its maximal reproductive competence. Aging leads to the accumulation of disabilities and diseases that limit normal body functions and is a major risk factor for neurodegenerative diseases. Many neurodegenerative diseases share oxidative stress and nitrosative stress as common terminal processes.

Iron-induced oxidative stress modulates olfactory learning and memory in honeybees.

Reactive oxygen species (ROS)-mediated oxidative stress tends to increase with environmental stress, aging, and age-related diseases resulting in progressive neuronal dysfunction. The purpose of the present study was to examine whether or not oxidative stress can be induced into the antennal lobes of the honeybee brain by injecting ferrous ammonium citrate (FAC). Proboscis Extension Reflex conditioning procedure was used to assay subjects' responses to odorants for evaluating the effect of oxidative stress on the olfactory learning and memory.

Comparison of biochemical effects of statins and fish oil in brain: the battle of the titans.

Neural membranes are composed of glycerophospholipids, sphingolipids, cholesterol and proteins. The distribution of these lipids within the neural membrane is not random but organized. Neural membranes contain lipid rafts or microdomains that are enriched in sphingolipids and cholesterol.

Octopamine-mediated neuronal plasticity in honeybees: implications for olfactory dysfunction in humans.

Biogenic amines, such as norepinephrine (in vertebrates) and octopamine (in invertebrates), have structural and functional similarities. These amines play crucial roles in animal behavior by modifying the synaptic output of relevant neurons. Increased levels of norepinephrine in the olfactory bulb preferentially increase mitral cell excitatory responses to olfactory nerve inputs, suggesting its critical role in modulating olfactory function including memory formation and/or recall of specific olfactory memories.

Octopamine-mediated neuromodulation of insect senses.

Octopamine functions as a neuromodulator, neurotransmitter, and neurohormone in insect nervous systems. Octopamine has a prominent role in influencing multiple physiological events: (a) as a neuromodulator, it regulates desensitization of sensory inputs, arousal, initiation, and maintenance of various rhythmic behaviors and complex behaviors such as learning and memory; (b) as a neurotransmitter, it regulates endocrine gland activity; and (c) as a neurohormone, it induces mobilization of lipids and carbohydrates. Octopamine exerts its effects by binding to specific proteins that belong to the superfamily of G protein-coupled receptors and share the structural motif of seven transmembrane domains.

Modulation of inflammation in brain: a matter of fat.

Neuroinflammation is a host defense mechanism associated with neutralization of an insult and restoration of normal structure and function of brain. Neuroinflammation is a hallmark of all major CNS diseases. The main mediators of neuroinflammation are microglial cells.