Ascorbic acid 6-palmitate modulates microglia M1/M2 polarization in lipopolysaccharide-stimulated BV-2 cells via PERK/elF2α mediated endoplasmic reticulum stress

Design, synthesis and biological evaluation of N-substituted nipecotamide derivatives as multifunctional agents for epilepsy treatment

To discover novel multi-functional antiepileptic agents, nipecotamide was hybridized with salicylaldehyde, paeonol, vanillin and cinnamaldehyde to generate a series of N-substituted nipecotamide derivatives. Biological screening revealed that compound 11c exhibited remarkable scavenging activities against ABTS (2,2'-Azinobis-(3-ethylbenzthiazoline-6-sulfonic acid)) radical (scavenging IC50: 92.0 μM), DPPH (1,1-Diphenyl-2-picrylhydrazyl) radical (scavenging IC50: 70.9 μM), and superoxide anion radical (inhibition percentage: 48.4 %). Additionally, electrophysiological results showed that compound 11c demonstrated potent inhibitory effects on abnormal electrical discharges. Furthermore, compound 11c displayed the capacity to relieve H2O2-induced oxidative damage and LPS-induced neuroinflammation at the cellular level. Besides, compound 11c could cross the blood-brain barrier, alleviate the symptoms of epilepsy induced by pentylenetetrazole and pilocarpine effectively, and mitigate oxidative damage caused by sodium nitrite in mice. Therefore, compound 11c possesses symptomatic-treatment and disease-modification properties for epilepsy. These results highlighted that compound 11c was a highly promising candidate for further development as an antiepileptic agent.

Deoxynivalenol-Induced Spleen Toxicity in Mice: Inflammation, Endoplasmic Reticulum Stress, Macrophage Polarization, and the Dysregulation of LncRNA Expression

The spleen is a primary target of deoxynivalenol (DON) toxicity, but its underlying molecular mechanisms remain unclear. This study investigates the effects of DON on inflammation, splenic macrophage polarization, endoplasmic reticulum (ER) stress, and transcriptome changes (mRNA and lncRNAs) in mouse spleen. We found that DON exposure at doses of 2.5 or 5 mg/kg BW significantly induced inflammation and polarized splenic macrophages towards the M1 phenotype. Additionally, DON activated PERK-eIF2α-ATF4-mediated ER stress and upregulated apoptosis-related proteins (caspase-12, caspase-3). The ER stress inhibitor, 4-Phenylbutyric acid, significantly alleviated DON-induced ER stress, apoptosis, and the M1 polarization of splenic macrophages. Transcriptome analysis identified 1968 differentially expressed (DE) lncRNAs and 2664 DE mRNAs in mouse spleen following DON exposure. Functional enrichment analysis indicated that the upregulated genes were involved in pathways associated with immunity, including Th17 cell differentiation, TNF signaling, and IL-17 signaling, while downregulated mRNAs were linked to cell survival and growth pathways. Furthermore, 370 DE lncRNAs were predicted to target 255 DE target genes associated with immune processes, including the innate immune response, interferon-beta response, cytokine production regulation, leukocyte apoptosis, and NF-κB signaling genes. This study provides new insights into the mechanisms underlying DON toxicity and its effects on the immune system.

L-AP Alleviates Liver Injury in Septic Mice by Inhibiting Macrophage Activation via Suppressing NF-κB and NLRP3 Inflammasome/Caspase-1 Signal Pathways

Liver injury and progressive liver failure are severe life-threatening complications in sepsis, further worsening the disease and leading to death. Macrophages and their mediated inflammatory cytokine storm are critical regulators in the occurrence and progression of liver injury in sepsis, for which effective treatments are still lacking. l-Ascorbic acid 6-palmitate (L-AP), a food additive, can inhibit neuroinflammation by modulating the phenotype of the microglia, but its pharmacological action in septic liver damage has not been fully explored. We aimed to investigate L-AP's antisepticemia action and the possible pharmacological mechanisms in attenuating septic liver damage by modulating macrophage function. We observed that L-AP treatment significantly increased survival in cecal ligation and puncture-induced WT mice and attenuated hepatic inflammatory injury, including the histopathology of the liver tissues, hepatocyte apoptosis, and the liver enzyme levels in plasma, which were comparable to NLRP3-deficiency in septic mice. L-AP supplementation significantly attenuated the excessive inflammatory response in hepatic tissues of septic mice in vivo and in cultured macrophages challenged by both LPS and ATP in vitro, by reducing the levels of NLRP3, pro-IL-1β, and pro-IL-18 mRNA expression, as well as the levels of proteins for p-I-κB-α, p-NF-κB-p65, NLRP3, cleaved-caspase-1, IL-1β, and IL-18. Additionally, it impaired the inflammasome ASC spot activation and reduced the inflammatory factor contents, including IL-1β and IL-18 in plasma/cultured superannuants. It also prevented the infiltration/migration of macrophages and their M1-like inflammatory polarization while improving their M2-like polarization. Overall, our findings revealed that L-AP protected against sepsis by reducing macrophage activation and inflammatory cytokine production by suppressing their activation in NF-κB and NLRP3 inflammasome signal pathways in septic liver.

Lipid metabolism transcriptomics of murine microglia in Alzheimer's disease and neuroinflammation

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by the accumulation of amyloid-β (Aβ) plaques followed by intracellular neurofibrillary tangles (NFTs) composed of hyperphosphorylated tau. An unrestrained immune response by microglia, the resident cells of the central nervous system (CNS), leads to neuroinflammation which can amplify AD pathology. AD pathology is also driven by metabolic dysfunction with strong correlations between dementia and metabolic disorders such as diabetes, hypercholesterolemia, and hypertriglyceridemia. Since elevated cholesterol and triglyceride levels appear to be a major risk factor for developing AD, we investigated the lipid metabolism transcriptome in an AD versus non-AD state using RNA-sequencing (RNA-seq) and microarray datasets from N9 cells and murine microglia. We identified 52 differentially expressed genes (DEG) linked to lipid metabolism in LPS-stimulated N9 microglia versus unstimulated control cells using RNA-seq, 86 lipid metabolism DEG in 5XFAD versus wild-type mice by microarray, with 16 DEG common between both datasets. Functional enrichment and network analyses identified several biological processes and molecular functions, such as cholesterol homeostasis, insulin signaling, and triglyceride metabolism. Furthermore, therapeutic drugs targeting lipid metabolism DEG found in our study were identified. Focusing on drugs that target genes associated with lipid metabolism and neuroinflammation could provide new targets for AD drug development.