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Cognitive impairment is a core feature of neurodevelopmental (schizophrenia) and aging-associated (mild cognitive impairment and Alzheimer's dementia) neurodegenerative diseases. Limited efficacy of current pharmacological treatments warrants further search for new targets for nootropic interventions. The breakdown of myelin, a phospholipids axonal sheath that protects the conduction of nerve impulse between neurons, was proposed as a neuropathological abnormality that precedes and promotes the deposition of amyloid-β in neuritic plaques. The present review of the recent literature and our own pre- and clinical data suggest (for the first time) that the anthranilic acid (AA)-induced activation of microglial-expressed G-protein coupled receptor (GPR109A) inhibits cytosolic phospholipase A2 (cPLA2), an enzyme that triggers the degradation of myelin and consequently attenuates cognitive impairment. The present review suggests that the up-regulation of AA formation is a sex-specific compensatory (adaptive) reaction aimed to prevent/treat cognitive impairment. The AA–GPR109A–cPLA2–myelin–cognition cascade suggests new nootropic interventions, e.g., the administration of pegylated kynureninase, an enzyme that catalyzes AA formation from Kynurenine (Kyn), a tryptophane catabolite; pegylated interferon-alpha; central and peripheral Kyn aminotransferase inhibitors that increase availability of Kyn as a substrate for AA formation; and vagus nerve stimulation. The cascade predicts nootropic activity of exogenous GPR109A agonists that were designed and underwent clinical trials (unsuccessful) as anti-dyslipidemia agents. The proposed cascade might contribute to the pathogenesis of cognitive impairment. Data on AA in neurodegenerative disorders are scarce, and the proposed cascade needs further exploration in pre- and clinical studies [ABSTRACT FROM AUTHOR]

Background and Purpose: Autophagy is a protective factor for controlling neuronal damage, while necroptosis promotes neuroinflammation after spinal cord injury (SCI). DADLE (D‐Ala2, D‐Leu5]‐enkephalin) is a selective agonist for delta (δ) opioid receptor and has been identified as a promising drug for neuroprotection. The aim of this study was to investigate the mechanism/s by which DADLE causes locomotor recovery following SCI. Experimental approach: Spinal cord contusion model was used and DADLE was given by i.p. (16 mg·kg−1) in mice for following experiments. Motor function was assessed by footprint and Basso mouse scale (BMS) score analysis. Western blotting used to evaluate related protein expression. Immunofluorescence showed the protein expression in each cell and its distribution. Network pharmacology analysis was used to find the related signalling pathways. Key Results: DADLE promoted functional recovery after SCI. In SCI model of mice, DADLE significantly increased autophagic flux and inhibited necroptosis. Concurrently, DADLE restored autophagic flux by decreasing lysosomal membrane permeabilization (LMP). Additionally, chloroquine administration reversed the protective effect of DADLE to inhibit necroptosis. Further analysis showed that DADLE decreased phosphorylated cPLA2, overexpression of cPLA2 partially reversed DADLE inhibitory effect on LMP and necroptosis, as well as the promotion autophagy. Finally, AMPK/SIRT1/p38 pathway regulating cPLA2 is involved in the action DADLE on SCI and naltrindole inhibited DADLE action on δ receptor and on AMPK signalling pathway. Conclusion and Implication: DADLE causes its neuroprotective effects on SCI by promoting autophagic flux and inhibiting necroptosis by decreasing LMP via activating δ receptor/AMPK/SIRT1/p38/cPLA2 pathway. [ABSTRACT FROM AUTHOR]

Physiologically, renal medullary cells are surrounded by a hyperosmolar interstitium. However, different pathological situations can induce abrupt changes in environmental osmolality, causing cell stress. Therefore, renal cells must adapt to survive in this new condition. We previously demonstrated that, among the mechanisms involved in osmoprotection, renal cells upregulate triglyceride biosynthesis (which helps preserve glycerophospholipid synthesis and membrane homeostasis) and cyclooxygenase‐2 (which generates prostaglandins from arachidonic acid) to maintain lipid metabolism in renal tissue. Herein, we evaluated whether hyperosmolality modulates phospholipase A2 (PLA2) activity, leading to arachidonic acid release from membrane glycerophospholipid, and investigated its possible role in hyperosmolality‐induced triglyceride synthesis and accumulation. We found that hyperosmolality induced PLA2 expression and activity in Madin‐Darby canine kidney cells. Cytosolic PLA2 (cPLA2) inhibition, but not secreted or calcium‐independent PLA2 (sPLA2 or iPLA2, respectively), prevented triglyceride synthesis and reduced cell survival. Inhibition of prostaglandin synthesis with indomethacin not only failed to prevent hyperosmolality‐induced triglyceride synthesis but also exacerbated it. Similar results were observed with the peroxisomal proliferator activated receptor gamma (PPARγ) agonist rosiglitazone. Furthermore, hyperosmolality increased free intracellular arachidonic acid levels, which were even higher when prostaglandin synthesis was inhibited by indomethacin. Blocking PPARγ with GW‐9662 prevented the effects of both indomethacin and rosiglitazone on triglyceride synthesis and even reduced hyperosmolality‐induced triglyceride synthesis, suggesting that arachidonic acid may stimulate triglyceride synthesis through PPARγ activation. These results highlight the role of cPLA2 in osmoprotection, since it is essential to provide arachidonic acid, which is involved in PPARγ‐regulated triglyceride synthesis, thus guaranteeing cell survival. [ABSTRACT FROM AUTHOR]

The blood–retinal barrier (BRB) is strongly compromised in diabetic retinopathy (DR) due to the detachment of pericytes (PCs) from retinal microvessels, resulting in increased permeability and impairment of the BRB. Western blots, immunofluorescence and ELISA were performed on adipose mesenchymal stem cells (ASCs) and pericyte-like (P)-ASCs by co-cultured human retinal endothelial cells (HRECs) under hyperglycemic conditions (HG), as a model of DR. Our results demonstrated that: (a) platelet-derived growth factor receptor (PDGFR) and its activated form were more highly expressed in monocultured P-ASCs than in ASCs, and this expression increased when co-cultured with HRECs under high glucose conditions (HG); (b) the transcription factor Nrf2 was more expressed in the cytoplasmic fraction of ASCs and in the P-ASC nuclear fraction, under normal glucose and, even more, under HG conditions; (c) cytosolic phospholipase A2 activity and prostaglandin E2 release, stimulated by HG, were significantly reduced in P-ASCs co-cultured with HRECs; (d) HO-1 protein content was significantly higher in HG-P-ASCs/HRECs than P-ASCs/HRECs; and (e) VEGF-A levels in media from HG-co-cultures were reduced in P-ASCs/HRECs with respect to ASCs/HRECs. The data obtained highlighted the potential of autologous differentiated ASCs in future clinical applications based on cell therapy to counteract the damage induced by DR. [ABSTRACT FROM AUTHOR]

ABSTRACTGlycoprotein VI (GPVI) is the major collagen receptor on the platelet surface and is important in mediating granule secretion and atherothrombosis. Sulforaphane (SFN), a dietary isothiocyanate enriched in cruciferous vegetables, exerts multiple biological activities. This study aimed to investigate the efficacy of SFN on GPVI-mediated signaling and platelet granule secretion in vitro. We herein demonstrated that SFN greatly attenuated granule secretion in human gel-filtered platelets in response to collagen, including inhibiting CD62P and CD63 expression and PF4, CCL5, and ATP release. Mechanistically, these inhibitory effects of SFN were mainly mediated by its attenuation of cytosolic phospholipase A2 (cPLA2) phosphorylation and thromboxane A2 (TxA2) generation. Moreover, SFN did not further decrease the inhibitory effects of p38 MAPK inhibitor SB203580 on cPLA2 phosphorylation, TxA2 generation and granule secretion. Thus, SFN attenuates platelet granule secretion via down-regulating GPVI-mediated p38 MAPK/cPLA2/TxA2 signaling, which may play important preventive roles in cardiovascular diseases.

Central nervous system (CNS) trauma, including traumatic brain injury and spinal cord injury, has a high rate of disability and mortality, and effective treatment is currently lacking. Previous studies have revealed that neural inflammation plays a vital role in CNS trauma. As the initial enzyme in neuroinflammation, cytosolic phospholipase A2 (cPLA2) can hydrolyze membranous phosphatides at the sn-2 position in a preferential way to release lysophospholipids and ω3-polyunsaturated fatty acid dominated by arachidonic acid, thereby inducing secondary injuries. Although there is substantial fresh knowledge pertaining to cPLA2, in-depth comprehension of how cPLA2 participates in CNS trauma and the potential methods to ameliorate the clinical results after CNS trauma are still insufficient. The present review summarizes the latest understanding of how cPLA2 participates in CNS trauma, highlighting novel findings pertaining to how cPLA2 activation initiates the potential mechanisms specifically, neuroinflammation, lysosome membrane functions, and autophagy activity, that damage the CNS after trauma. Moreover, we focused on testing a variety of drugs capable of inhibiting cPLA2 or the upstream pathway, and we explored how those agents might be utilized as treatments to improve the results following CNS trauma. This review aimed to effectively understand the mechanism of cPLA2 activation and its role in the pathophysiological processes of CNS trauma and provide clarification and a new referential framework for future research.

Glycoprotein VI (GPVI) is the major collagen receptor on the platelet surface and is important in mediating granule secretion and atherothrombosis. Sulforaphane (SFN), a dietary isothiocyanate enriched in cruciferous vegetables, exerts multiple biological activities. This study aimed to investigate the efficacy of SFN on GPVI-mediated signaling and platelet granule secretion in vitro. We herein demonstrated that SFN greatly attenuated granule secretion in human gel-filtered platelets in response to collagen, including inhibiting CD62P and CD63 expression and PF4, CCL5, and ATP release. Mechanistically, these inhibitory effects of SFN were mainly mediated by its attenuation of cytosolic phospholipase A2 (cPLA2) phosphorylation and thromboxane A2 (TxA2) generation. Moreover, SFN did not further decrease the inhibitory effects of p38 MAPK inhibitor SB203580 on cPLA2 phosphorylation, TxA2 generation and granule secretion. Thus, SFN attenuates platelet granule secretion via down-regulating GPVI-mediated p38 MAPK/cPLA2/TxA2 signaling, which may play important preventive roles in cardiovascular diseases. [ABSTRACT FROM AUTHOR]

Spinal cord injury (SCI) leads to permanent motor and sensory loss that is exacerbated by intraspinal inflammation and persists months to years after injury. After SCI, monocyte-derived macrophages (MDMs) infiltrate the lesion to aid in myelin-rich debris clearance. During debris clearance, MDMs adopt a proinflammatory phenotype that exacerbates neurodegeneration and hinders recovery. The underlying cause of the lipid-mediated MDM phenotype shift is unclear. Our previous work suggests that cytosolic phospholipase A2 (cPLA2) plays a role in the proinflammatory potentiating effect of myelin on macrophages in vitro. Cytosolic phospholipase A2 (cPLA2) frees arachidonic acid from phospholipids, generating eicosanoids that play an important role in inflammation, immunity, and host defense. cPLA2 is expressed in macrophages along with multiple other cell types after SCI, and cPLA2 inhibition has been reported to both reduce and exacerbate secondary injury pathology recovery. The role of cPLA2 in MDMs after SCI is not fully understood. We hypothesize that cPLA2 activation in MDMs after SCI contributes to secondary injury. Here, we report that cPLA2 plays an important role in the myelin-induced inflammatory macrophage phenotype in vitro using macrophages derived from cPLA2 knockout bone marrow. Furthermore, to investigate the role of cPLA2 in MDMs after SCI, we generated female bone marrow chimeras using cPLA2 knock-out donors and assessed locomotor recovery using the Basso Mouse Scale (BMS), CatWalk gait analysis system, and horizontal ladder task over six weeks. We also evaluated tissue sparing and intralesional axon density six weeks after injury. cPLA2 KO chimeras did not display altered locomotor recovery or tissue pathology after SCI compared to WT chimera controls. These data suggest that although cPLA2 plays a critical role in myelin-mediated potentiation of proinflammatory macrophage activation in vitro, it may not contribute to secondary injury pathology in vivo after SCI., Competing Interests: Declarations. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Necrosis that appears at the ischemic distal end of random-pattern skin flaps increases the pain and economic burden of patients. Necroptosis is thought to contribute to flap necrosis. Lysosomal membrane permeabilization (LMP) plays an indispensable role in the regulation of necroptosis. Nonetheless, the mechanisms by which lysosomal membranes become leaky and the relationship between necroptosis and lysosomes are still unclear in ischemic flaps. Based on Western blotting, immunofluorescence, enzyme-linked immunosorbent assay, and liquid chromatography-mass spectrometry (LC-MS) analysis results, we found that LMP was presented in the ischemic distal portion of random-pattern skin flaps, which leads to disruption of lysosomal function and macroautophagic/autophagic flux, increased necroptosis, and aggravated necrosis of the ischemic flaps. Moreover, bioinformatics analysis of the LC-MS results enabled us to focus on the role of PLA2G4E/cPLA2 (phospholipase A2, group IVE) in LMP of the ischemic flaps. In vivo inhibition of PLA2G4E with an adeno-associated virus vector attenuated LMP and necroptosis, and promoted flap survival. In addition, microRNA-seq helped us determine that Mir504-5p was differentially expressed in ischemic flaps. A string of in vitro and in vivo tests was employed to verify the inhibitory effect of Mir504-5p on PLA2G4E, LMP and necroptosis. Finally, we concluded that the inhibition of PLA2G4E by Mir504-5p reduced LMP-induced necroptosis, thereby promoting the survival of random-pattern skin flaps. Abbreviations: AAV: adeno-associated virus; ACTA2/α;-SMA: actin alpha 2, smooth muscle, aorta; ALOX15/12/15-LOX: arachidonate 15- lipoxygenase; c-CASP8: cleaved caspase; c-CASP3: cleaved caspase 3; CTSD: cathepsin D; CTSB: cathepsin B; CTSL: cathepsin L; DMECs: primary mouse dermal microvascular endothelial cells; ELISA: enzyme-linked immunosorbent assay; F-CHP: 5-FAM-conjugated collagen hybridizing peptide; FISH: fluorescence in situ hybridization; HUVECs: human umbilical vein endothelial cells; LAMP1: lysosomal-associated membrane protein 1; LAMP2: lysosomal-associated membrane protein 2; LC-MS: liquid chromatography-mass spectrometry; LDBF: laser doppler blood flow; LMP: lysosomal membrane permeabilization; LPE: lysophosphatidylethanolamine; LPC: lysophosphatidylcholine; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; MLKL: mixed lineage kinase domain-like; NDI: N-dodecylimidazole; PECAM1/CD31: platelet/endothelial cell adhesion molecule 1; PLA2G4A/cPLA2: phospholipase A2, group IVA (cytosolic, calcium-dependent); PLA2G4E/cPLA2: phospholipase A2, group IVE; qPCR: quantitative real-time polymerase chain reaction; RIPK1: receptor (TNFRSF)-interacting serine-threonine kinase 1; RIPK3: receptor-interacting serine-threonine kinase 3; RISC: RNA-induced silencing complex; ROS: reactive oxygen species; shRNA: short hairpin RNA; SQSTM1: sequestosome 1; TBHP: tert-butyl hydroperoxide; TUNEL: terminal deoxynucleotidyl transferase dUTP nick end labelling. [ABSTRACT FROM AUTHOR]

[Display omitted] Valproic acid (VPA) has broad efficacy against several seizures but causes liver injury limiting its prolonged clinical use. Some studies have demonstrated that VPA-induced hepatotoxicity is characterized by microvesicular hepatic steatosis. However, novel detailed mechanisms to explain VPA-induced hepatic steatosis and experimentally rigorously validated protective agents are still lacking. In this study, 8-week-old C57BL/6J mice were gavaged with VPA (500 mg/kg/d) for 4 weeks to establish an in vivo model of VPA-induced chronic liver injury. Quantitative proteomic and non-targeted lipidomic analyses were performed to explore the underlying mechanisms of VPA-induced hepatotoxicity. As a result, VPA-induced hepatotoxicity is associated with impaired autophagic flux, which is attributed to lysosomal dysfunction. Further studies revealed that VPA-induced lysosomal membrane permeabilization (LMP), allows soluble lysosomal enzymes to leak into the cytosol, which subsequently led to impaired lysosomal acidification. A lower abundance of glycerophospholipids and an increased abundance of lysophospholipids in liver tissues of mice in the VPA group strongly indicated that VPA-induced LMP may be mediated by the activation of phospholipase PLA2G4A. Metformin (Met) acted as a potential protective agent attenuating VPA-induced liver dysfunction and excessive lipid accumulation. Molecular docking and cellular thermal shift assays demonstrated that Met inhibited the activity of PLA2G4A by directly binding to it, thereby ameliorating VPA-induced LMP and autophagic flux impairment. In conclusion, this study highlights the therapeutic potential of targeting PLA2G4A-mediated lysosomal dysfunction in VPA-induced hepatotoxicity. [ABSTRACT FROM AUTHOR]

Spinal cord injury (SCI) leads to permanent motor and sensory loss that is exacerbated by intraspinal inflammation that persists months to years after injury. After SCI, monocyte-derived macrophages (MDMs) infiltrate the lesion to aid in myelin-rich debris clearance. During debris clearance, MDMs adopt a proinflammatory phenotype that exacerbates neurodegeneration and hinders recovery. The underlying cause of the lipid-mediated MDM phenotype shift is unclear. Our previous work suggests that cytosolic phospholipase A2 (cPLA2) plays a role in the proinflammatory potentiating effect of myelin on macrophages in vitro . Cytosolic phospholipase A2 (cPLA2) frees arachidonic acid from phospholipids, generating eicosanoids that play an important role in inflammation, immunity, and host defense. cPLA2 is expressed in macrophages along with multiple other cell types after SCI, and cPLA2 inhibition has been reported to both reduce and exacerbate secondary injury pathology recovery. The role of cPLA2 in MDMs after SCI is not fully understood. We hypothesize that cPLA2 activation in MDMs after SCI contributes to secondary injury. Here, we report that cPLA2 plays an important role in the myelin-induced inflammatory macrophage phenotype in vitro using macrophages derived from cPLA2 knockout bone marrow. Furthermore, to investigate the role of cPLA2 in MDMs after SCI, we generated female bone marrow chimeras using cPLA2 knock-out donors and assessed locomotor recovery using the Basso Mouse Scale (BMS), CatWalk gait analysis system, and horizontal ladder task over six weeks. We also evaluated tissue sparing and intralesional axon density six weeks after injury. cPLA2 KO chimeras did not display altered locomotor recovery or tissue pathology after SCI compared to WT chimera controls. These data suggest that although cPLA2 plays a critical role in myelin-mediated potentiation of proinflammatory macrophage activation in vitro , it may not contribute to secondary injury pathology in vivo after SCI., Competing Interests: Declarations of Competing Interest No authors report any competing or conflicts of interest regarding this work.

Cytosolic phospholipase A2 (cPLA2) is an enzyme regulating membrane phospholipid homeostasis and the release of arachidonic acid utilized in inflammatory responses. It represents an attractive target for the treatment of Alzheimer’s disease (AD). Previously, we showed that lipopolysaccharide (LPS)-induced systemic inflammation caused abnormal lipid metabolism in the brain of a transgenic AD mouse model (APdE9), which might be associated with potential changes in cPLA2 activity. Here, we investigated changes in cPLA2 expression and activity, as well as the molecular mechanisms underlying these alterations due to chronic LPS administration in the cerebral cortex of female APdE9 mice as compared to saline- and LPS-treated female wild-type mice and saline-treated APdE9 mice. The study revealed the significant effects of genotype LPS treatment on cortical cPLA2 protein expression and activity in APdE9 mice. LPS treatment resulted in nuclear factor kappa-light-chain-enhancer of activated B cells (NFkB) activation in the cortex of APdE9 mice. The gene expressions of inflammation markers Il1b and Tnfa were significantly elevated in the cortex of both APdE9 groups compared to the wild-type groups. The study provides evidence of the elevated expression and activity of cPLA2 in the brain cortex of APdE9 mice after chronic LPS treatment, which could be associated with NFkB activation.

Recent studies have revealed that lipid droplets accumulate in neurons after brain injury and evoke lipotoxicity, damaging the neurons. However, how lipids are metabolized by spinal cord neurons after spinal cord injury remains unclear. Herein, we investigated lipid metabolism by spinal cord neurons after spinal cord injury and identified lipid-lowering compounds to treat spinal cord injury. We found that lipid droplets accumulated in perilesional spinal cord neurons after spinal cord injury in mice. Lipid droplet accumulation could be induced by myelin debris in HT22 cells. Myelin debris degradation by phospholipase led to massive free fatty acid production, which increased lipid droplet synthesis, β-oxidation, and oxidative phosphorylation. Excessive oxidative phosphorylation increased reactive oxygen species generation, which led to increased lipid peroxidation and HT22 cell apoptosis. Bromocriptine was identified as a lipid-lowering compound that inhibited phosphorylation of cytosolic phospholipase A2 by reducing the phosphorylation of extracellular signal-regulated kinases 1/2 in the mitogen-activated protein kinase pathway, thereby inhibiting myelin debris degradation by cytosolic phospholipase A2 and alleviating lipid droplet accumulation in myelin debris-treated HT22 cells. Motor function, lipid droplet accumulation in spinal cord neurons and neuronal survival were all improved in bromocriptine-treated mice after spinal cord injury. The results suggest that bromocriptine can protect neurons from lipotoxic damage after spinal cord injury via the extracellular signal-regulated kinases 1/2-cytosolic phospholipase A2 pathway., Competing Interests: None

Background and Purpose: Autophagy is a protective factor for controlling neuronal damage, while necroptosis promotes neuroinflammation after spinal cord injury (SCI). DADLE (D-Ala 2 , D-Leu 5 ]-enkephalin) is a selective agonist for delta (δ) opioid receptor and has been identified as a promising drug for neuroprotection. The aim of this study was to investigate the mechanism/s by which DADLE causes locomotor recovery following SCI., Experimental Approach: Spinal cord contusion model was used and DADLE was given by i.p. (16 mg·kg -1 ) in mice for following experiments. Motor function was assessed by footprint and Basso mouse scale (BMS) score analysis. Western blotting used to evaluate related protein expression. Immunofluorescence showed the protein expression in each cell and its distribution. Network pharmacology analysis was used to find the related signalling pathways., Key Results: DADLE promoted functional recovery after SCI. In SCI model of mice, DADLE significantly increased autophagic flux and inhibited necroptosis. Concurrently, DADLE restored autophagic flux by decreasing lysosomal membrane permeabilization (LMP). Additionally, chloroquine administration reversed the protective effect of DADLE to inhibit necroptosis. Further analysis showed that DADLE decreased phosphorylated cPLA 2 , overexpression of cPLA 2 partially reversed DADLE inhibitory effect on LMP and necroptosis, as well as the promotion autophagy. Finally, AMPK/SIRT1/p38 pathway regulating cPLA 2 is involved in the action DADLE on SCI and naltrindole inhibited DADLE action on δ receptor and on AMPK signalling pathway., Conclusion and Implication: DADLE causes its neuroprotective effects on SCI by promoting autophagic flux and inhibiting necroptosis by decreasing LMP via activating δ receptor/AMPK/SIRT1/p38/cPLA 2 pathway., (© 2023 British Pharmacological Society.)

Physiologically, renal medullary cells are surrounded by a hyperosmolar interstitium. However, different pathological situations can induce abrupt changes in environmental osmolality, causing cell stress. Therefore, renal cells must adapt to survive in this new condition. We previously demonstrated that, among the mechanisms involved in osmoprotection, renal cells upregulate triglyceride biosynthesis (which helps preserve glycerophospholipid synthesis and membrane homeostasis) and cyclooxygenase-2 (which generates prostaglandins from arachidonic acid) to maintain lipid metabolism in renal tissue. Herein, we evaluated whether hyperosmolality modulates phospholipase A 2 (PLA 2 ) activity, leading to arachidonic acid release from membrane glycerophospholipid, and investigated its possible role in hyperosmolality-induced triglyceride synthesis and accumulation. We found that hyperosmolality induced PLA 2 expression and activity in Madin-Darby canine kidney cells. Cytosolic PLA 2 (cPLA2) inhibition, but not secreted or calcium-independent PLA 2 (sPLA 2 or iPLA 2 , respectively), prevented triglyceride synthesis and reduced cell survival. Inhibition of prostaglandin synthesis with indomethacin not only failed to prevent hyperosmolality-induced triglyceride synthesis but also exacerbated it. Similar results were observed with the peroxisomal proliferator activated receptor gamma (PPARγ) agonist rosiglitazone. Furthermore, hyperosmolality increased free intracellular arachidonic acid levels, which were even higher when prostaglandin synthesis was inhibited by indomethacin. Blocking PPARγ with GW-9662 prevented the effects of both indomethacin and rosiglitazone on triglyceride synthesis and even reduced hyperosmolality-induced triglyceride synthesis, suggesting that arachidonic acid may stimulate triglyceride synthesis through PPARγ activation. These results highlight the role of cPLA 2 in osmoprotection, since it is essential to provide arachidonic acid, which is involved in PPARγ-regulated triglyceride synthesis, thus guaranteeing cell survival., (© 2023 Federation of European Biochemical Societies.)

Background: Alzheimer's disease (AD) is a neurodegenerative disorder lacking any curative treatment up to now. Indeed, actual medication given to the patients alleviates only symptoms. The cytosolic phospholipase A2 (cPLA 2 -IVA) appears as a pivotal player situated at the center of pathological pathways leading to AD and its inhibition could be a promising therapeutic approach., Objective: A cPLA 2 -IVA inhibiting peptide was identified in the present work, aiming to develop an original therapeutic strategy., Methods: We targeted the cPLA 2 -IVA using the phage display technology. The hit peptide PLP25 was first validated in vitro (arachidonic acid dosage [AA], cPLA 2 -IVA cellular translocation) before being tested in vivo . We evaluated spatial memory using the Barnes maze, amyloid deposits by MRI and immunohistochemistry (IHC), and other important biomarkers such as the cPLA 2 -IVA itself, the NMDA receptor, AβPP and tau by IHC after i.v. injection in APP/PS1 mice., Results: Showing a high affinity for the C2 domain of this enzyme, the peptide PLP25 exhibited an inhibitory effect on cPLA 2 -IVA activity by blocking its binding to its substrate, resulting in a decreased release of AA. Coupled to a vector peptide (LRPep2) in order to optimize brain access, we showed an improvement of cognitive abilities of APP/PS1 mice, which also exhibited a decreased number of amyloid plaques, a restored expression of cPLA 2 -IVA, and a favorable effect on NMDA receptor expression and tau protein phosphorylation., Conclusions: cPLA 2 -IVA inhibition through PLP25 peptide could be a promising therapeutic strategy for AD., Competing Interests: The authors have no conflict of interest to report., (© 2023 – The authors. Published by IOS Press.)

Objective: To investigate the mechanism of cytosolic phospholipase A2(cPLA2) inhibitor to improve neurological function after spinal cord injury (SCI)., Methods: Thirty-six 3 months old female SD rats, with body mass (280±20) g, were divided into three groups ( n =12):sham group, SCI group, and SCI+ arachidonyl trifluoromethyl ketone(AACOCF3) group. Balloon compression SCI model was established in all three groups. In the sham model group, the spinal cord compression model was created after the balloon was placed without pressure treatment, and the remaining two groups were pressurized with the balloon for 48 h. After successful modeling, rats in the SCI+AACOCF3 group were injected intraperitoneally with AACOCF3, a specific inhibitor of cPLA2. The remaining two groups of rats were injected intraperitoneally with saline. The animals were sacrificed in batches on 7 and 14 days after modeling, respectively. And the damaged spinal cord tissues were sampled for pathomorphological observation, to detect the expression of cPLA2 and various autophagic fluxPrelated molecules and test the recovery of motor function., Results: Spinal cord histomorphometry examination showed that the spinal cord tissue in the sham group was structurally intact, with normal numbers and morphology of neurons and glial cells. In the SCI group, spinal cord tissue fractures with large and prominent spinal cord cavities were seen. In the SCI+AACOCF3 group, the spinal cord tissue was more intact than in the SCI group, with more fused spinal cord cavities, more surviving neurons, and less glial cell hyperplasia. Western blot showed that the sham group had the lowest protein expression of LC3-Ⅱ, Beclin 1, p62, and cPLA2 compared with the SCI and SCI+AACOCF3 groups ( P <0.05) and the highest protein expression of LC3-Ⅰ ( P <0.05). P62 and cPLA2 expression in the SCI group were higher than in the SCI+AACOCF3 group ( P <0.05). Behavioral observations showed that the time corresponding to BBB exercise scores was significantly lower in both the SCI and SCI+AACOCF3 groups than in the sham group ( P <0.05). Scores at 3, 7, and 14 days after pressurization were higher in the SCI+AACOCF3 group than in the SCI group ( P <0.05)., Conclusion: cPLA2 inhibitors can reduce neuronal damage secondary to SCI, promote neurological recovery and improve motor function by improving lysosomal membrane permeability and regulating autophagic flux.

Objective: To observe the effect of electroacupuncture（EA） on the expression of cytosolic phospholipase A2 （cPLA2） and apoptosis of nerve cells in rats with spinal cord injury （SCI）, so as to explore its mechanisms underlying improvement of SCI., Methods: Seventy-two female SD rats were randomly divided into model, EA, antagonist and EA+antagonist groups, with 18 rats in each group and other 18 rats were used as the sham operation （sham） group. The SCI model was established by referring to modified Allen's method with a weight impactor. The hindlimb motor function was assessed by using Basso-Beattie-Bresnahan （BBB） score. Rats of the EA group were subjected to EA stimulation at "Dazhui"（GV14）, "Yaoyangguan"（GV3）, bilateral "Ciliao"（BL32） and "Zusanli"（ST36） for 20 min, once a day for 14 days. Rats of the antagonist group received intravenous injection followed by intraperitoneal injection of arachidonyl trifluoromethyl ketone （AACOCF3, antagonist of cPLA2）, once every other day. Rats of the EA+antagonist group received EA treatment combined with antagonist injection. After the treatment, the rats were sacrificed and the spinal cord tissue was collected for detecting the protein expression of cPLA2, p-cPLA2, Bcl-2, Bax and Caspase-3 by Western blot, and the mRNA expression of cPLA2, Bcl-2, Bax and Caspase-3 using qRT-PCR. The morphological changes of the spinal cord were detected by Nissl staining., Results: In comparison with the sham group, the BBB score, expression of Bcl-2 protein and mRNA were significantly down-regulated （ P <0.01）, whereas the expression levels of Bax, Caspase-3 and p-cPLA2 proteins and mRNAs were considerably up-regulated in the model group （ P <0.01）. Compared with the model group, the BBB score, expression levels of Bcl-2 protein and mRNA were significantly up-regulated （ P <0.01, P <0.05）, while the expression levels of Bax, Caspase-3 and p-cPLA2 proteins in the EA, antagonist and EA+antagonist groups, Bax and cPLA2 mRNAs in both antagonist and EA+antagonist groups, and Caspase-3 mRNA in the EA+antagonist group were obviously down-regulated （ P <0.01, P <0.05）. The effect of EA+antagonist was significantly superior to EA in increasing BBB score and in lowering expression of Bax and cPLA2 mRNAs （ P <0.01, P <0.05）. Nissl staining showed reduced number of nerve cells and Nissl bodies, and striped dark blue cells in the model group, which was milder in the EA and antagonist groups, particularly in the EA+antagonist group., Conclusion: EA may improve the limb motor function of SCI rats, which may be related to its functions in down-regulating the expression of p-cPLA2, Bax and Caspase-3 and up-regulating Bcl-2 to reduce the apoptosis of nerve cells in the regional spinal cord.

• FFD reduced macrophage and neutrophil infiltration in lung tissue. • FFD inhibited the production of cytokines and chemokines. • FFD reduced downstream hydrolysis of cPLA2 arachidonic acid and leukotriene B4. • FFD inhibited LPS-induced cPLA2/ERK/P65 signaling pathway by targeting cPLA2. Acute lung injury (ALI) causes acute respiratory distress syndrome, with a high mortality rate of 40%, with currently available pharmacological treatments. Cytosolic phospholipase A2 (cPLA2) plays a critical role in the lipopolysaccharide (LPS)-induced pathology of ALI. This study assessed the therapeutic effects of fexofenadine (FFD), an on-market small-molecule drug that can target cPLA2 in LPS-induced ALI. Primary macrophages obtained from the bone marrow of wild-type and cPLA2 knockout mice and the alveolar macrophage cell line, MHS were used to test the inhibitory effect of FFD on the cPLA2/ERK/p65 signaling pathway, NF-κB p65 translocation, and cytokine and chemokine production. An LPS-induced ALI mouse model was used to assess the treatment effects of FFD. Flow cytometry detected subsets of macrophages and neutrophils. cPLA2 activity and downstream hydrolysates were detected. Treatment with a cPLA2 inhibitor or NF-κB p65 inhibitor confirmed that FFD functioned through the cPLA2/ERK/p65 signaling pathway by targeting cPLA2. FFD reduced the infiltration of macrophages and neutrophils, decreased the protein secretion in bronchoalveolar lavage fluid, and reduced the production of TNFα, IL-1β, IL-6, MCP-1, and IL-8 in the lung, bronchoalveolar lavage fluid, and sera of LPS-induced ALI mice. FFD inhibited cPLA2 activity, suppressed the cPLA2/ERK/p65 signaling pathway, inhibited translocation of p65, and decreased the production of cytokines, chemokines, and downstream hydrolysates of cPLA2, arachidonic acid, and leukotriene B4. FFD inhibits the cPLA2/ERK/p65 signaling pathway by targeting cPLA2. Therefore, FFD is promising as a therapeutic against cPLA2-involved diseases, particularly ALI. [ABSTRACT FROM AUTHOR]

Cytosolic phospholipase A2 (cPLA2) is an enzyme regulating membrane phospholipid homeostasis and the release of arachidonic acid utilized in inflammatory responses. It represents an attractive target for the treatment of Alzheimer's disease (AD). Previously, we showed that lipopolysaccharide (LPS)-induced systemic inflammation caused abnormal lipid metabolism in the brain of a transgenic AD mouse model (APdE9), which might be associated with potential changes in cPLA2 activity. Here, we investigated changes in cPLA2 expression and activity, as well as the molecular mechanisms underlying these alterations due to chronic LPS administration in the cerebral cortex of female APdE9 mice as compared to saline- and LPS-treated female wild-type mice and saline-treated APdE9 mice. The study revealed the significant effects of genotype LPS treatment on cortical cPLA2 protein expression and activity in APdE9 mice. LPS treatment resulted in nuclear factor kappa-light-chain-enhancer of activated B cells (NFkB) activation in the cortex of APdE9 mice. The gene expressions of inflammation markers Il1b and Tnfa were significantly elevated in the cortex of both APdE9 groups compared to the wild-type groups. The study provides evidence of the elevated expression and activity of cPLA2 in the brain cortex of APdE9 mice after chronic LPS treatment, which could be associated with NFkB activation., Competing Interests: The authors declare no conflict of interest.

Juxtaglomerular cells or granular cells synthesize, store, and secrete renin needed for the renin-angiotensin-aldosterone (RAS) to fine tune the maintenance of blood pressure and blood volume. The baroreceptor function of these granular cells may function as a nuclear mechanotransducer to sense and transmit the extracellular physical forces to their chromatin to regulate renin gene expression and secretion. Cell nucleus serves as a sensor and responds to the changes in pressure and stretch that triggers calcium release and cPLA2 (cytosolic phospholipase A2) activation that, in turn, releases arachidonic acid (AA) (and possibly, other unsaturated fatty acids) from the cell membrane lipid pool. AA influences the cytoskeletal system and is involved and regulates exocytosis. AA is the precursor of a variety of products that have a regulatory role in the formation and action of RAS, inflammation, and immune response. These results imply that AA is involved in nuclear mechanotransduction mechanism in the baroreceptor function of granular cells and in the regulation of synthesis and secretion of renin. [ABSTRACT FROM AUTHOR]