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Journal of Neuroinflammation Feb 2023Demyelination occurs in multiple central nervous system (CNS) disorders and is tightly associated with neuroinflammation. Pyroptosis is a form of pro-inflammatory and...
Regulatory T cells alleviate myelin loss and cognitive dysfunction by regulating neuroinflammation and microglial pyroptosis via TLR4/MyD88/NF-κB pathway in LPC-induced demyelination.
Demyelination occurs in multiple central nervous system (CNS) disorders and is tightly associated with neuroinflammation. Pyroptosis is a form of pro-inflammatory and lytic cell death which has been observed in CNS diseases recently. Regulatory T cells (Tregs) have exhibited immunoregulatory and protective effects in CNS diseases. However, the roles of Tregs in pyroptosis and their involvement in LPC-induced demyelination have not been explicated. In our study, Foxp3-diphtheria toxin receptor (DTR) mice treated with diphtheria toxin (DT) or PBS were subjected to two-site lysophosphatidylcholine (LPC) injection. Immunofluorescence, western blot, Luxol fast blue (LFB) staining, quantitative real-time PCR (qRT-PCR) and neurobehavior assessments were performed to evaluate the severity of demyelination, neuroinflammation and pyroptosis. Pyroptosis inhibitor was further used to investigate the role of pyroptosis in LPC-induced demyelination. RNA-sequencing was applied to explore the potential regulatory mechanism underlying the involvement of Tregs in LPC-induced demyelination and pyroptosis. Our results showed that depletion of Tregs aggravated microgliosis, inflammatory responses, immune cells infiltration and led to exacerbated myelin injury as well as cognitive defects in LPC-induced demyelination. Microglial pyroptosis was observed after LPC-induced demyelination, which was aggravated by Tregs depletion. Inhibition of pyroptosis by VX765 reversed myelin injury and cognitive function exacerbated by Tregs depletion. RNA-sequencing showed TLR4/myeloid differentiation marker 88 (MyD88) as the central molecules in Tregs-pyroptosis pathway, and refraining TLR4/MyD88/NF-κB pathway alleviated the aggravated pyroptosis induced by Tregs depletion. In conclusion, our findings for the first time indicate that Tregs alleviate myelin loss and improve cognitive function by inhibiting pyroptosis in microglia via TLR4/MyD88/NF-κB pathway in LPC-induced demyelination.
Topics: Mice; Animals; NF-kappa B; Signal Transduction; Toll-Like Receptor 4; Myeloid Differentiation Factor 88; Microglia; Lysophosphatidylcholines; Neuroinflammatory Diseases; Pyroptosis; Myelin Sheath; T-Lymphocytes, Regulatory; Cognitive Dysfunction; RNA; Demyelinating Diseases
PubMed: 36803990
DOI: 10.1186/s12974-023-02721-0 -
Biomarkers in Medicine 2016Lysophosphatidic acid (LPA), a lipid mediator in biological fluids and tissues, is generated mainly by autotaxin that hydrolyzes lysophosphatidylcholine to LPA and... (Review)
Review
Lysophosphatidic acid (LPA), a lipid mediator in biological fluids and tissues, is generated mainly by autotaxin that hydrolyzes lysophosphatidylcholine to LPA and choline. Total LPA levels are increased in bronchoalveolar lavage fluid from asthmatic lung, and are strongly induced following subsegmental bronchoprovocation with allergen in subjects with allergic asthma. Polyunsaturated molecular species of LPA (C22:5 and C22:6) are selectively synthesized in the airways of asthma subjects following allergen challenge and in mouse models of allergic airway inflammation, having been identified and quantified by LC/MS/MS lipidomics. This review discusses current knowledge of LPA production in asthmatic lung and the potential utility of polyunsaturated LPA molecular species as novel biomarkers in bronchoalveolar lavage fluid and exhaled breath condensate of asthma subjects.
Topics: Adult; Airway Remodeling; Allergens; Animals; Asthma; Biomarkers; Bronchoalveolar Lavage Fluid; Disease Models, Animal; Humans; Inflammation; Lung; Lysophosphatidylcholines; Lysophospholipids; Mice; Phospholipases A1; Phosphoric Diester Hydrolases; Receptors, Lysophosphatidic Acid
PubMed: 26808693
DOI: 10.2217/bmm.15.93 -
BMC Geriatrics Mar 2022Metabolic profiling may provide insights into the pathogenesis and identification of sarcopenia; however, data on the metabolic basis of sarcopenia and muscle-related...
BACKGROUND
Metabolic profiling may provide insights into the pathogenesis and identification of sarcopenia; however, data on the metabolic basis of sarcopenia and muscle-related parameters among older adults remain incompletely understood. This study aimed to identify the associations of metabolites with sarcopenia and its components, and to explore metabolic perturbations in older men, who have a higher prevalence of sarcopenia than women.
METHODS
We simultaneously measured the concentrations of amino acids, carnitine, acylcarnitines, and lysophosphatidylcholines (LPCs) in serum samples from a cross-sectional study of 246 Chinese older men, using targeted metabolomics. Sarcopenia and its components, including skeletal muscle index (SMI), 6-m gait speed, and handgrip strength were assessed according to the algorithm of the Asian Working Group for Sarcopenia criteria. Associations were determined by univariate and multivariate analyses.
RESULTS
Sixty-five (26.4%) older men with sarcopenia and 181 (73.6%) without sarcopenia were included in the study. The level of isovalerylcarnitine (C5) was associated with the presence of sarcopenia and SMI. Regarding the overlapped metabolites for muscle parameters, among ten metabolites associated with muscle mass, six metabolites including leucine, octanoyl-L-carnitine (C8), decanoyl-L-carnitine (C10), dodecanoyl-L-carnitine (C12) and tetradecanoyl-L-carnitine (C14), and LPC18:2 were associated with handgrip strength, and three of which (C12, C14, and LPC18:2) were also associated with gait speed. Specifically, tryptophan was positively associated and glycine was negatively associated with handgrip strength, while glutamate was positively correlated with gait speed. Isoleucine, branched chain amino acids, and LPC16:0 were positively associated with SMI. Moreover, the levels of LPC 16:0,18:2 and 18:0 contributed significantly to the model discriminating between older men with and without sarcopenia, whereas there were no significant associations for other amino acids, acylcarnitines, and LPC lipids.
CONCLUSIONS
These results showed that specific and overlapped metabolites are associated with sarcopenic parameters in older men. This study highlights the potential roles of acylcarnitines and LPCs in sarcopenia and its components, which may provide valuable information regarding the pathogenesis and management of sarcopenia.
Topics: Aged; Amino Acids; Carnitine; Cross-Sectional Studies; Female; Hand Strength; Humans; Lysophosphatidylcholines; Male; Muscle, Skeletal; Sarcopenia
PubMed: 35337292
DOI: 10.1186/s12877-022-02953-4 -
Gastroenterology Jul 2021Limited understanding of pruritus mechanisms in cholestatic liver diseases hinders development of antipruritic treatments. Previous studies implicated lysophosphatidic...
BACKGROUND & AIMS
Limited understanding of pruritus mechanisms in cholestatic liver diseases hinders development of antipruritic treatments. Previous studies implicated lysophosphatidic acid (LPA) as a potential mediator of cholestatic pruritus.
METHODS
Pruritogenicity of lysophosphatidylcholine (LPC), LPA's precursor, was examined in naïve mice, cholestatic mice, and nonhuman primates. LPC's pruritogenicity involving keratinocyte TRPV4 was studied using genetic and pharmacologic approaches, cultured keratinocytes, ion channel physiology, and structural computational modeling. Activation of pruriceptor sensory neurons by microRNA-146a (miR-146a), secreted from keratinocytes, was identified by in vitro and ex vivo Ca imaging assays. Sera from patients with primary biliary cholangitis were used for measuring the levels of LPC and miR-146a.
RESULTS
LPC was robustly pruritic in mice. TRPV4 in skin keratinocytes was essential for LPC-induced itch and itch in mice with cholestasis. Three-dimensional structural modeling, site-directed mutagenesis, and channel function analysis suggested a TRPV4 C-terminal motif for LPC binding and channel activation. In keratinocytes, TRPV4 activation by LPC induced extracellular release of miR-146a, which activated TRPV1 sensory neurons to cause itch. LPC and miR-146a levels were both elevated in sera of patients with primary biliary cholangitis with itch and correlated with itch intensity. Moreover, LPC and miR-146a were also increased in sera of cholestatic mice and elicited itch in nonhuman primates.
CONCLUSIONS
We identified LPC as a novel cholestatic pruritogen that induces itch through epithelia-sensory neuron cross talk, whereby it directly activates skin keratinocyte TRPV4, which rapidly releases miR-146a to activate skin-innervating TRPV1 pruriceptor sensory neurons. Our findings support the new concept of the skin, as a sensory organ, playing a critical role in cholestatic itch, beyond liver, peripheral sensory neurons, and central neural pathways supporting pruriception.
Topics: Adult; Aged; Animals; Behavior, Animal; Cells, Cultured; Cholestasis; Disease Models, Animal; Female; Humans; Keratinocytes; Lysophosphatidylcholines; Macaca mulatta; Male; Mice, Inbred C57BL; Mice, Knockout; Middle Aged; Pruritus; Sensory Receptor Cells; Signal Transduction; Skin; TRPV Cation Channels; Mice
PubMed: 33819485
DOI: 10.1053/j.gastro.2021.03.049 -
Proceedings of the National Academy of... Oct 2023α-synuclein (α-Syn) is a presynaptic protein that is involved in Parkinson's and other neurodegenerative diseases and binds to negatively charged phospholipids....
α-synuclein (α-Syn) is a presynaptic protein that is involved in Parkinson's and other neurodegenerative diseases and binds to negatively charged phospholipids. Previously, we reported that α-Syn clusters synthetic proteoliposomes that mimic synaptic vesicles. This vesicle-clustering activity depends on a specific interaction of α-Syn with anionic phospholipids. Here, we report that α-Syn surprisingly also interacts with the neutral phospholipid lysophosphatidylcholine (lysoPC). Even in the absence of anionic lipids, lysoPC facilitates α-Syn-induced vesicle clustering but has no effect on Ca-triggered fusion in a single vesicle-vesicle fusion assay. The A30P mutant of α-Syn that causes familial Parkinson disease has a reduced affinity to lysoPC and does not induce vesicle clustering. Taken together, the α-Syn-lysoPC interaction may play a role in α-Syn function.
Topics: Humans; alpha-Synuclein; Synaptic Vesicles; Lysophosphatidylcholines; Parkinson Disease; Phospholipids
PubMed: 37883437
DOI: 10.1073/pnas.2310174120 -
Cells Sep 2020The physiological fate of cells that die by apoptosis is their prompt and efficient removal by efferocytosis. During these processes, apoptotic cells release... (Review)
Review
The physiological fate of cells that die by apoptosis is their prompt and efficient removal by efferocytosis. During these processes, apoptotic cells release intracellular constituents that include purine nucleotides, lysophosphatidylcholine (LPC), and Sphingosine-1-phosphate (S1P) that induce migration and chemo-attraction of phagocytes as well as mitogens and extracellular membrane-bound vesicles that contribute to apoptosis-induced compensatory proliferation and alteration of the extracellular matrix and the vascular network. Additionally, during efferocytosis, phagocytic cells produce a number of anti-inflammatory and resolving factors, and, together with apoptotic cells, efferocytic events have a homeostatic function that regulates tissue repair. These homeostatic functions are dysregulated in cancers, where, aforementioned events, if not properly controlled, can lead to cancer progression and immune escape. Here, we summarize evidence that apoptosis and efferocytosis are exploited in cancer, as well as discuss current translation and clinical efforts to harness signals from dying cells into therapeutic strategies.
Topics: Apoptosis; Caspases; Cell Death; Humans; Lysophosphatidylcholines; Lysophospholipids; Molecular Targeted Therapy; Neoplasms; Phagocytosis; Phosphatidylserines; Purine Nucleotides; Sphingosine; Tumor Escape; Tumor Microenvironment
PubMed: 33003477
DOI: 10.3390/cells9102207 -
Nutrients Nov 2023Multiple studies have indicated that distinct metabolites are involved in the occurrence and development of osteopenia (ON) and osteoporosis (OP); however, these... (Meta-Analysis)
Meta-Analysis Review
Multiple studies have indicated that distinct metabolites are involved in the occurrence and development of osteopenia (ON) and osteoporosis (OP); however, these metabolites in OP and ON have not yet been classified and standardized. This systematic review and meta-analysis included 21 articles aiming to investigate the distinct metabolites in patients with ON and OP. The quality of the included articles was generally high; seventeen studies had >7 stars, and the remaining four received 6 stars. This systematic review showed that three metabolites (phosphatidylcholine (PC) (lipid metabolites), galactose (carbohydrate metabolites), and succinic acid (other metabolites)) increased, four (glycylglycine (gly-gly), cystine (amino acids), sphingomyelin (SM) (lipid metabolites) and glucose (carbohydrate metabolites)) decreased, and five (glutamine, hydroxyproline, taurine (amino acids), lysophosphatidylcholine (LPC) (lipid metabolites), and lactate (other metabolites)) had conflicting directions in OP/ON. The results of the meta-analysis show that gly-gly (MD = -0.77, 95%CI -1.43 to -0.11, = 0.02) and cystine (MD = -5.52, 95%CI -7.35 to -3.68, < 0.00001) decreased in the OP group compared with the healthy control group. Moreover, LPC (MD = 1.48, 95%CI 0.11 to 2.86, = 0.03) increased in the OP group compared with the healthy control group. These results indicate that distinct metabolites were associated with ON and OP, which could be considered a predictor for OP.
Topics: Humans; Cystine; Osteoporosis; Bone Diseases, Metabolic; Amino Acids; Lysophosphatidylcholines; Carbohydrates
PubMed: 38068753
DOI: 10.3390/nu15234895 -
International Journal of Molecular... Oct 2021Inflammatory bowel diseases (IBD) comprise a distinct set of clinical symptoms resulting from chronic inflammation within the gastrointestinal (GI) tract. Despite the... (Review)
Review
Inflammatory bowel diseases (IBD) comprise a distinct set of clinical symptoms resulting from chronic inflammation within the gastrointestinal (GI) tract. Despite the significant progress in understanding the etiology and development of treatment strategies, IBD remain incurable for thousands of patients. Metabolic deregulation is indicative of IBD, including substantial shifts in lipid metabolism. Recent data showed that changes in some phospholipids are very common in IBD patients. For instance, phosphatidylcholine (PC)/phosphatidylethanolamine (PE) and lysophosphatidylcholine (LPC)/PC ratios are associated with the severity of the inflammatory process. Composition of phospholipids also changes upon IBD towards an increase in arachidonic acid and a decrease in linoleic and a-linolenic acid levels. Moreover, an increase in certain phospholipid metabolites, such as lysophosphatidylcholine, sphingosine-1-phosphate and ceramide, can result in enhanced intestinal inflammation, malignancy, apoptosis or necroptosis. Because some phospholipids are associated with pathogenesis of IBD, they may provide a basis for new strategies to treat IBD. Current attempts are aimed at controlling phospholipid and fatty acid levels through the diet or via pharmacological manipulation of lipid metabolism.
Topics: Animals; Humans; Inflammatory Bowel Diseases; Intestinal Mucosa; Lipid Metabolism; Phospholipids
PubMed: 34769112
DOI: 10.3390/ijms222111682 -
Acta Poloniae Pharmaceutica 2014For many years the role of lysophospholipids (LPLs) was associated only with structural and storage components of the cell without any informational function. Today,... (Review)
Review
For many years the role of lysophospholipids (LPLs) was associated only with structural and storage components of the cell without any informational function. Today, based on many research projects performed during the last decades, it is clear that some of the LPLs act as hormone-like signaling molecules and thus are very important inter- and intracellular lipid mediators. They can activate specific membrane receptors and/or nuclear receptors regulating many crucial physiological and pathophysiological processes. The LPLs were iden- tified as involved in a majority of cellular processes, including modulation of disease-related mechanisms observed, for instance, in case of diabetes, obesity, atherosclerosis and cancer. Among LPLs, lysophosphatidylcholine (LPC) and lysophosphatidylinositol (LPI) are becoming attractive research topics. Their recently revealed activities as novel ligands of orphan G protein-coupled receptors (i.e., GPR55 and GPR119) involved in modulation of tumor physiology and insulin secretion seem to be one of the most interesting aspects of these compounds. Moreover, the most recent scientific reports emphasize the significance of the acyl chain structure bound to the glycerol basis of LPL, as it entails different biological properties and activities of the compounds.
Topics: Animals; Diabetes Mellitus; Humans; Ligands; Lysophosphatidylcholines; Lysophospholipids; Neoplasms; Receptors, Cannabinoid; Receptors, G-Protein-Coupled; Signal Transduction
PubMed: 25745761
DOI: No ID Found -
International Journal of Molecular... Jul 2022The bioactive lipid lysophosphatidylcholine (LPC), a major phospholipid component of oxidized low-density lipoprotein (Ox-LDL), originates from the cleavage of... (Review)
Review
The bioactive lipid lysophosphatidylcholine (LPC), a major phospholipid component of oxidized low-density lipoprotein (Ox-LDL), originates from the cleavage of phosphatidylcholine by phospholipase A2 (PLA2) and is catabolized to other substances by different enzymatic pathways. LPC exerts pleiotropic effects mediated by its receptors, G protein-coupled signaling receptors, Toll-like receptors, and ion channels to activate several second messengers. Lysophosphatidylcholine (LPC) is increasingly considered a key marker/factor positively in pathological states, especially inflammation and atherosclerosis development. Current studies have indicated that the injury of nervous tissues promotes oxidative stress and lipid peroxidation, as well as excessive accumulation of LPC, enhancing the membrane hyperexcitability to induce chronic pain, which may be recognized as one of the hallmarks of chronic pain. However, findings from lipidomic studies of LPC have been lacking in the context of chronic pain. In this review, we focus in some detail on LPC sources, biochemical pathways, and the signal-transduction system. Moreover, we outline the detection methods of LPC for accurate analysis of each individual LPC species and reveal the pathophysiological implication of LPC in chronic pain, which makes it an interesting target for biomarkers and the development of medicine regarding chronic pain.
Topics: Atherosclerosis; Chronic Pain; Humans; Lipoproteins, LDL; Lysophosphatidylcholines; Phospholipases A2; Receptors, G-Protein-Coupled; Signal Transduction
PubMed: 35955410
DOI: 10.3390/ijms23158274