OBJECTIVE: To observe the effects of "olfactory three needles" on cognition, learning and memory abilities, as well as hippocampal microglia (MG) phagocytic activity in vascular dementia (VD) rats, and explore the mechanisms of acupuncture in regulating MG activation and improving remyelination, so as to ameliorate VD. METHODS: Among 38 SD rats meeting experimental requirements, 9 rats were randomly assigned to a sham-operation group, and the remaining rats underwent permanent bilateral common carotid artery ligation to establish VD model. Eighteen successfully modeled rats were randomly divided into a model group and an electroacupuncture (EA) group, with 9 rats in each one. In the EA group, EA was performed at "olfactory three needles" ("Yintang" [GV24⁺] and bilateral "Yingxiang" [LI20]), at disperse-dense wave, the frequency of 2 Hz/15 Hz and the current intensity of 1 mA, for 15 min per intervention, once daily. One course was composed of 7 days, and 2 courses were required, with the interval of 2 days. The novel object recognition test was employed to assess the cognition of rats, and the Morris water maze was adopted to observe learning and memory abilities. Luxol fast blue (LFB) staining was performed to evaluate myelin sheath loss in the hippocampus, the Western blot was used to detect the protein expression of triggering receptor expressed on myeloid cells-2 (TREM2) and proteolipid protein (PLP) in the hippocampus; and the immunofluorescence staining was used to detect the positive expression of PLP, sex determining region Y-box 10 (SOX10), ionized calcium binding adaptor molecule 1 (Iba1)⁺ TREM2⁺ and Iba1⁺ lysosome-associated membrane protein 1 (LAMP1)⁺ in the hippocampus. RESULTS: Compared with the sham-operation group, the rats in the model group exhibited the prolonged escape latency on day 3 and 4 (P<0.05, P<0.01), the increase of the total distance traveling (P<0.01) and the decrease of the recognition index (RI) and platform crossing frequency (P<0.01). Compared with the model group, the rats in the EA group showed the shortened escape latency on day 3 and 4 (P<0.05), the decrease of total distance traveling (P<0.01) and the increase of RI and platform crossing frequency (P<0.05, P<0.01). When compared with the sham-operation group, the rats of the model group presented uneven staining, sparse arrangement of myelin sheath fibers, unclear contours, and prominent vacuole-like changes in the hippocampal CA1 region. When compared with the model group, the EA group showed more dense staining, the increase of myelin sheath fibers with more orderly alignment, and fewer vacuolar changes in the hippocampal CA1 region. Compared with the sham-operation group, the model group exhibited the increase of TREM2 protein expression and the decrease of PLP protein expression in the hippocampus (P<0.01), whereas the EA group showed the up-regulation of TREM2 and PLP protein expression when compared with the model group (P<0.01, P<0.05). The positive expression of the hippocampal PLP, SOX10, and Iba1⁺LAMP1⁺ in the model group was reduced in comparison with the sham-operation group (P<0.05, P<0.01), and the positive expression of Iba1⁺ TREM2⁺ was elevated (P<0.05). In the EA group, the positive expression of PLP, SOX10, Iba1⁺TREM2⁺, and Iba1⁺ LAMP1⁺ was higher compared with that in the model group (P<0.05, P<0.01). CONCLUSION "Olfactory three needles" can improve the learning and memory, and cognitive functions of VD rats, and its mechanism may be associated with the up-regulation of TREM2 and LAMP1 to adjust MG phagocytic activity and intracellular degradation, and promote remyelination.
Animals ; Dementia, Vascular/metabolism* ; Rats ; Rats, Sprague-Dawley ; Microglia/metabolism* ; Male ; Acupuncture Therapy/instrumentation* ; Acupuncture Points ; Humans ; Remyelination ; Memory ; Hippocampus/cytology* ; Cognition ; Electroacupuncture ; Needles

OBJECTIVE: To observe the effects of electroacupuncture (EA) on improving motor function and regulating microglial activation based on Notch receptor 1 (Notch1)/Hes family bHLH transcription factor 1 (Hes1) pathway in mice with Parkinson's disease (PD). METHODS: Thirty-six male C57BL/6 mice were randomly divided into a control group, a model group and an EA group, 12 mice in each group. PD model was established by intraperitoneal injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) for 7 consecutive days in the model group and the EA group. From the 1st day of modeling, EA was applied at "Baihui" (GV20) and bilateral "Shenshu" (BL23) in the EA group, with continuous wave, in frequency of 2 Hz and current of 2 mA, 15 min a time, once a day for 14 days continuously. The behavioral performance was evaluated by gait test, pole climbing test and hanging test, the number of positive cells of tyrosine hydroxylase (TH) and the co-expression positive cells of Notch1/ionized calcium binding adaptor molecule 1 (Iba-1) in the substantia nigra of midbrain was assessed by immunofluorescence, the protein expression of TH, α-synuclein (α-syn), Notch1, Hes1, Iba-1, inducible nitric oxide synthase (iNOS), Arginase-1 (ARG1), tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6 and IL-10 was detected by Western blot, the mRNA expression of Notch1 and Hes1 was detected by real-time PCR. RESULTS: Compared with the control group, in the model group, the stride frequency was accelerated (P<0.001) and the stride length was shortened (P<0.001) for the four limbs, the pole climbing test time was prolonged (P<0.01) and the grip level was reduced (P<0.01); in the substantia nigra of midbrain, the number of positive cells of TH was decreased (P<0.001), the number of co-expression positive cells of Notch1/Iba-1 was increased (P<0.001), the protein expression of α-syn, Notch1, Hes1, Iba-1, iNOS, TNF-α, IL-1βand IL-6 was increased (P<0.01, P<0.05, P<0.001), the protein expression of TH, ARG1 and IL-10 was decreased (P<0.01, P<0.001), the mRNA expression of Notch1 and Hes1 was increased (P<0.01). Compared with the model group, in the EA group, the stride frequency was decelerated (P<0.001) and the stride length was increased (P<0.05, P<0.01, P<0.001) for the four limbs, the pole climbing test time was shortened (P<0.05) and the grip level was increased (P<0.05); in the substantia nigra of midbrain, the number of positive cells of TH was increased (P<0.01), the number of co-expression positive cells of Notch1/Iba-1 was decreased (P<0.001), the protein expression of α-syn, Notch1, Hes1, Iba-1, iNOS, TNF-α, IL-6 and IL-1β was decreased (P<0.05, P<0.01), the protein expression of TH, ARG1 and IL-10 was increased (P<0.05, P<0.001, P<0.01), the mRNA expression of Notch1 and Hes1 was decreased (P<0.05). CONCLUSION EA can improve the behavioral performance and protect the dopaminergic neurons in PD mice, its mechanism may relate to the inhibition of Notch1/Hes1-mediated neuroinflammation, thus inhibiting the microglial activation.
Animals ; Electroacupuncture ; Microglia/metabolism* ; Male ; Receptor, Notch1/metabolism* ; Parkinson Disease/physiopathology* ; Transcription Factor HES-1/metabolism* ; Mice ; Mice, Inbred C57BL ; Humans ; Signal Transduction

The study aimed to investigate the effect of the CD200R1 gene deletion on microglia activation and nigrostriatal dopamine neuron loss in the Parkinson's disease (PD) process. The CRISPR-Cas9 technology was applied to construct the CD200R1^-/- mice. The primary microglia cells of wild-type and CD200R1^-/- mice were cultured and treated with bacterial lipopolysaccharide (LPS). Microglia phagocytosis level was assessed by a fluorescent microsphere phagocytosis assay. PD mouse model was prepared by nigral stereotaxic injection of recombinant adeno-associated virus vector carrying human α-synuclein (α-syn). The changes in the motor behavior of the mice with both genotypes were evaluated by cylinder test, open field test, and rotarod test. Immunohistochemical staining was used to assess the loss of dopamine neurons in substantia nigra. Immunofluorescence staining was used to detect the expression level of CD68 (a key molecule involved in phagocytosis) in microglia. The results showed that CD200R1 deletion markedly enhanced LPS-induced phagocytosis in vitro by the microglial cells. In the mouse model of PD, CD200R1 deletion exacerbated motor behavior impairment and dopamine neuron loss in substantia nigra. Fluorescence intensity analysis results revealed a significant increase in CD68 expression in microglia located in the substantia nigra of CD200R1^-/- mice. The above results suggest that CD200R1 deletion may further activates microglia by promoting microglial phagocytosis, leading to increased loss of the nigrostriatal dopamine neurons in the PD model mice. Therefore, targeting CD200R1 could potentially serve as a novel therapeutic target for the treatment of early-stage PD.
Animals ; Microglia/physiology* ; Mice ; Phagocytosis ; Parkinson Disease/genetics* ; Disease Models, Animal ; Receptors, Cell Surface/physiology* ; Dopaminergic Neurons/pathology* ; Antigens, CD/metabolism* ; Gene Deletion ; Substantia Nigra ; Mice, Inbred C57BL ; Mice, Knockout ; Cells, Cultured ; Male ; alpha-Synuclein ; CD68 Molecule ; Orexin Receptors

Based on the α7 nicotinic acetylcholine receptor(α7nAChR), this study examined how tetrahydropalmatine(THP) affected BV2 microglia exposed to lipopolysaccharide(LPS), aiming to clarify the possible mechanism underlying the anti-depression effect of THP from the perspectives of preventing inflammation and regulating polarization. First, after molecular docking and determination of the content of Corydalis saxicola Bunting total alkaloids, THP was initially identified as a possible anti-depression component. The BV2 microglia model of inflammation was established with LPS. BV2 microglia were allocated into a normal group, a model group, low-and high-dose(20 and 40 μmol·L~(-1), respectively) THP groups, and a THP(20 μmol·L~(-1))+α7nAChR-specific antagonist MLA(1 μmol·L~(-1)) group. The CCK-8 assay was used to screen the safe concentration of THP. A light microscope was used to examine the morphology of the cells. Western blot and immunofluorescence were used to determine the expression of α7nAChR. qRT-PCR was performed to determine the mRNA levels of inducible nitric oxide synthase(iNOS), cluster of differentiation 86(CD86), suppressor of cytokine signaling 3(SOCS3), arginase-1(Arg-1), cluster of differentiation 206(CD206), tumor necrosis factor(TNF)-α, interleukin(IL)-6, and IL-1β. Enzyme-linked immunosorbent assay(ELISA) was employed to measure the levels of TNF-α, IL-6, and IL-1β in the cell supernatant. The experimental results showed that THP at concentrations of 40 μmol·L~(-1) and below had no effect on BV2 microglia. THP improved the morphology of BV2 microglia, significantly up-regulated the protein level of α7nAChR, significantly down-regulated the mRNA levels of iNOS, CD86, SOCS3, TNF-α, IL-6, and IL-1β, significantly up-regulated the mRNA levels of Arg-1 and CD206, and dramatically lowered the levels of TNF-α, IL-6, and IL-1β in the cell supernatant. However, the antagonist MLA abolished the above-mentioned ameliorative effects of THP on LPS-treated BV2 microglia. As demonstrated by the aforementioned findings, THP protected LPS-treated BV2 microglia by regulating the M1/M2 polarization and preventing inflammation, which might be connected to the regulation of α7nAChR on BV2 microglia.
Berberine Alkaloids/chemistry* ; alpha7 Nicotinic Acetylcholine Receptor/chemistry* ; Microglia/metabolism* ; Mice ; Animals ; Cell Line ; Corydalis/chemistry* ; Humans ; Molecular Docking Simulation ; Inflammation/drug therapy* ; Nitric Oxide Synthase Type II/immunology* ; Tumor Necrosis Factor-alpha/immunology*

Study on the mechanism of Fangxia Dihuang Formula(FXDH) in treating breast cancer complicated with depression through the regulation of M1/M2 microglial polarization via the PERK/eIF2α axis. In addition to control group and 4T1 group, a mouse model of breast cancer complicated with depression was established using 4T1 cells combined with corticosterone. The mice were divided into model group, PERK/eIF2α signaling axis agonist(CCT020312, 2 mg·kg~(-1)·d~(-1)) group, CCT020312(2 mg·kg~(-1)·d~(-1)) + FXDH(13.65 g·kg~(-1)·d~(-1)) group, FXDH(13.65 g·kg~(-1)·d~(-1)) group, FXDH(13.65 g·kg~(-1)·d~(-1)) + Capecitabine Tablets(CAP, 390 mg·kg~(-1)·d~(-1)) group, and Fluoxetine Hydrochloride Capsules(FXT, 2.6 mg·kg~(-1)·d~(-1)) + CAP(390 mg·kg~(-1)·d~(-1)) group, with continuous intervention for 21 d. Depression-like behaviors in mice were assessed through sugar preference test and open field test. Hematoxylin-eosin(HE) staining was used to evaluate the morphology of tumor and hippocampal DG region neurons. Nissl staining was employed to detect changes in Nissl bodies in the hippocampal CA3 region. Immunofluorescence was used to observe cluster of differentiation 86(CD86)/ionized calcium-binding adapter molecule 1(Iba-1) and cluster of differentiation 206(CD206)/Iba-1 in hippocampal tissue. Real-time fluorescence quantitative polymerase chain reaction(RT-qPCR) was used to detect the mRNA expression of M1-type microglia [interleukin-6(IL-6), tumor necrosis factor-α(TNF-α)] and M2-type [arginase-1(Arg-1), IL-10] in hippocampal tissue. Western blot was used to detect the protein expression of key factors in the PERK/eIF2α axis, including PERK, eIF2α, activating transcription factor 4(ATF4), and C/EBP homologous protein(CHOP) in hippocampal tissue. The results showed that compared to model group/CCT020312 + FXDH group, FXDH group increased sugar preference index, total movement distance, central zone distance, and central zone entries; reduced tumor mass and volume; tumor cells were sparsely arranged, with a smaller nuclear-to-cytoplasmic ratio and reduced nuclear division figures, increased Nissl body count, and alleviated neuronal nuclear pyknosis; increased CD206-positive M2-type microglia expression, decreased CD86/Iba-1-positive M1-type microglia expression; reduced IL-6 and TNF-α mRNA expression, and increased Arg-1 and IL-10 mRNA expression; downregulated PERK, eIF2α, ATF4, and CHOP protein expression levels. The results indicate that the mechanism of FXDH in treating breast cancer complicated with depression may be related to inhibiting the activity of the PERK/eIF2α axis, reducing the proportion of M1-type microglia, increasing the proportion of M2-type microglia, thereby suppressing neuronal immune inflammation, improving depressive symptoms, and subsequently delaying the progression of breast cancer.
Animals ; Drugs, Chinese Herbal/administration & dosage* ; Female ; Microglia/cytology* ; Mice ; Depression/complications* ; eIF-2 Kinase/genetics* ; Humans ; Breast Neoplasms/psychology* ; Eukaryotic Initiation Factor-2/genetics* ; Mice, Inbred BALB C ; Signal Transduction/drug effects* ; Cell Line, Tumor

This study aims to explore the effects and action mechanisms of the active ingredients in Buyang Huanwu Decoction(BYHWD), namely tetramethylpyrazine(TMP) and hydroxy-safflor yellow A(HSYA), on oxygen-glucose deprivation/reglucose-reoxygenation(OGD/R)-induced inflammation and oxidative stress of microglia(MG). Network pharmacology was used to screen the effective monomer ingredients of BYHWD and determine the safe concentration range for each component. Inflammation and oxidative stress models were established to further screen the best ingredient combination and optimal concentration ratio with the most effective anti-inflammatory and antioxidant effects. OGD/R BV2 cell models were constructed, and BV2 cells in the logarithmic growth phase were divided into a normal group, a model group, an HSYA group, a TMP group, and an HSYA + TMP group. Enzyme-linked immunosorbent assay(ELISA) was used to detect the levels of inflammatory cytokines such as interleukin-1β(IL-1β), tumor necrosis factor-α(TNF-α), and interleukin-6(IL-6). Oxidative stress markers, including superoxide dismutase(SOD), nitric oxide(NO), and malondialdehyde(MDA), were also measured. Western blot was used to analyze the protein expression of both inflammation-related pathway [Toll-like receptor 4(TLR4)/nuclear factor-kappa B(NF-κB)] and oxidative stress-related pathway [nuclear factor erythroid 2-related factor 2(Nrf2)/heme oxygenase-1(HO-1)]. Immunofluorescence was used to assess the expression of proteins such as inducible nitric oxide synthase(iNOS) and arginase-1(Arg-1). The most effective ingredients for anti-inflammatory and antioxidant effects in BYHWD were TMP and HSYA. Compared to the normal group, the model group showed significantly increased levels of IL-1β, TNF-α, IL-6, NO, and MDA, along with significantly higher protein expression of NF-κB, TLR4, Nrf2, and HO-1 and significantly lower SOD levels. The differences between the two groups were statistically significant. Compared to the model group, both the HSYA group and the TMP group showed significantly reduced levels of IL-1β, TNF-α, IL-6, NO, and MDA, lower expression of NF-κB and TLR4 proteins, higher levels of SOD, and significantly increased protein expression of Nrf2 and HO-1. Additionally, the expression of the M1-type MG marker iNOS was significantly reduced, while the expression of the M2-type MG marker Arg-1 was significantly increased. The results of the HSYA group and the TMP group had statistically significant differences from those of the model group. Compared to the HSYA group and the TMP group, the HSYA + TMP group showed further significant reductions in IL-1β, TNF-α, IL-6, NO, and MDA levels, along with significant reductions in NF-κB and TLR4 protein expression, an increase in SOD levels, and elevated Nrf2 and HO-1 protein expression. Additionally, the expression of the M1-type MG marker iNOS was reduced, while the M2-type MG marker Arg-1 expression increased significantly in the HSYA + TMP group compared to the TMP or HSYA group. The differences in the results were statistically significant between the HSYA + TMP group and the TMP or HSYA group. The findings indicated that the combined use of HSYA and TMP, the active ingredients of BYHWD, can effectively inhibit OGD/R-induced inflammation and oxidative stress of MG, showing superior effects compared to the individual use of either component.
Oxidative Stress/drug effects* ; Drugs, Chinese Herbal/pharmacology* ; Animals ; Mice ; Glucose/metabolism* ; Cell Line ; Inflammation/genetics* ; Oxygen/metabolism* ; Pyrazines/pharmacology* ; Microglia/metabolism* ; NF-E2-Related Factor 2/immunology* ; NF-kappa B/immunology* ; Toll-Like Receptor 4/immunology* ; Anti-Inflammatory Agents/pharmacology* ; Humans

Stem-leaf saponins from Panax notoginseng (SLSP) comprise numerous PPD-type saponins with diverse pharmacological properties; however, their role in Parkinson's disease (PD), characterized by microglia-mediated neuroinflammation, remains unclear. This study evaluated the effects of SLSP on suppressing microglia-driven neuroinflammation in experimental PD models, including the 1-methyl-4-phenylpyridinium (MPTP)-induced mouse model and lipopolysaccharide (LPS)-stimulated BV-2 microglia. Our findings revealed that SLSP mitigated behavioral impairments and excessive microglial activation in models of PD, including MPTP-treated mice. Additionally, SLSP inhibited the upregulation of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX2) and attenuated the phosphorylation of PI3K, protein kinase B (AKT), nuclear factor-κB (NFκB), and inhibitor of NFκB protein α (IκBα) both in vivo and in vitro. Moreover, SLSP suppressed the production of inflammatory markers such as interleukin (IL)-1β, IL-6, and tumor necrosis factor alpha (TNF-α) in LPS-stimulated BV-2 cells. Notably, the P2Y2R agonist partially reversed the inhibitory effects of SLSP in LPS-treated BV-2 cells. These results suggest that SLSP inhibit microglia-mediated neuroinflammation in experimental PD models, likely through the P2Y2R/PI3K/AKT/NFκB signaling pathway. These novel findings indicate that SLSP may offer therapeutic potential for PD by attenuating microglia-mediated neuroinflammation.
Animals ; Panax notoginseng/chemistry* ; Saponins/pharmacology* ; Microglia/immunology* ; Mice ; NF-kappa B/immunology* ; Signal Transduction/drug effects* ; Proto-Oncogene Proteins c-akt/immunology* ; Phosphatidylinositol 3-Kinases/genetics* ; Male ; Parkinson Disease/immunology* ; Mice, Inbred C57BL ; Disease Models, Animal ; Plant Leaves/chemistry* ; Neuroinflammatory Diseases/drug therapy* ; Humans

Microglia, the resident immune cells in the central nervous system (CNS), rapidly transition from a resting to an active state in the acute phase of ischemic brain injury. This active state mediates a pro-inflammatory response that can exacerbate the injury. Targeting the pro-inflammatory response of microglia in the semi-dark band during this acute phase may effectively reduce brain injury. Shionone (SH), an active ingredient extracted from the dried roots and rhizomes of the genus Aster (Asteraceae), has been reported to regulate the inflammatory response of macrophages in sepsis-induced acute lung injury. However, its function in post-stroke neuroinflammation, particularly microglia-mediated neuroinflammation, remains uninvestigated. This study found that SH significantly inhibited lipopolysaccharide (LPS)-induced elevation of inflammatory cytokines, including interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and inducible nitric oxide synthase (iNOS), in microglia in vitro. Furthermore, the results demonstrated that SH alleviated infarct volume and improved behavioral performance in middle cerebral artery occlusion (MCAO) mice, which may be attributed to the inhibition of the microglial inflammatory response induced by SH treatment. Mechanistically, SH potently inhibited the phosphorylation of serine-threonine protein kinase B (AKT), mammalian target of rapamycin (mTOR), and signal transducer and activator of transcription 3 (STAT3). These findings suggest that SH may be a potential therapeutic agent for relieving ischemic stroke (IS) by alleviating microglia-associated neuroinflammation.
Animals ; Microglia/immunology* ; Mice ; Male ; Mice, Inbred C57BL ; Brain Ischemia/immunology* ; Neuroinflammatory Diseases/drug therapy* ; Neuroprotective Agents/administration & dosage* ; Interleukin-1beta/genetics* ; STAT3 Transcription Factor/genetics* ; TOR Serine-Threonine Kinases/genetics* ; Tumor Necrosis Factor-alpha/genetics* ; Proto-Oncogene Proteins c-akt/immunology* ; Nitric Oxide Synthase Type II/genetics* ; Lipopolysaccharides

Triggering receptor expressed on myeloid cells 2 (TREM2)-mediated microglial phagocytosis is an energy-intensive process that plays a crucial role in amyloid beta (Aβ) clearance in Alzheimer's disease (AD). Energy metabolic reprogramming (EMR) in microglia induced by TREM2 presents therapeutic targets for cognitive impairment in AD. Jiawei Xionggui Decoction (JWXG) has demonstrated effectiveness in enhancing energy supply, protecting microglia, and mitigating cognitive impairment in APP/PS1 mice. However, the mechanism by which JWXG enhances Aβ phagocytosis through TREM2-mediated EMR in microglia remains unclear. This study investigates how JWXG facilitates microglial phagocytosis and alleviates cognitive deficits in AD through TREM2-mediated EMR. Microglial phagocytosis was evaluated through immunofluorescence staining in vitro and in vivo. The EMR level of microglia was assessed using high-performance liquid chromatography (HPLC) and enzyme-linked immunosorbent assay (ELISA) kits. The TREM2/protein kinase B (Akt)/mammalian target of rapamycin (mTOR)/hypoxia-inducible factor-1α (HIF-1α) signaling pathway was analyzed using Western blotting in BV₂ cells. TREM2^-/- BV₂ cells were utilized for reverse validation experiments. The Aβ burden, neuropathological features, and cognitive ability in APP/PS1 mice were evaluated using ELISA kits, immunohistochemistry (IHC), and the Morris water maze (MWM) test. JWXG enhanced both the phagocytosis of EMR disorder-BV₂ cells (EMRD-BV₂) and increased EMR levels. Notably, these effects were significantly reversed in TREM2^-/- BV₂ cells. JWXG elevated TREM2 expression, adenosine triphosphate (ATP) levels, and microglial phagocytosis in APP/PS1 mice. Additionally, JWXG reduced Aβ-burden, neuropathological lesions, and cognitive deficits in APP/PS1 mice. In conclusion, JWXG promoted TREM2-induced EMR and enhanced microglial phagocytosis, thereby reducing Aβ deposition, improving neuropathological lesions, and alleviating cognitive deficits.
Drugs, Chinese Herbal/pharmacology* ; Microglia/drug effects* ; Phagocytosis ; Cognitive Dysfunction/drug therapy* ; Metabolic Reprogramming ; Animals ; Mice ; Cell Line ; Receptors, Immunologic/metabolism* ; Membrane Glycoproteins/metabolism* ; Signal Transduction ; Amyloid beta-Peptides/metabolism* ; Energy Metabolism

Lirispirolides A-L (1-12), twelve novel sesquiterpene-monoterpene heterodimers featuring distinctive carbon skeletons, were isolated from the branches and leaves of Chinese tulip tree [Liriodendron chinense (L. chinense)], a rare medicinal and ornamental plant endemic to China. The structural elucidation was accomplished through comprehensive spectroscopic analyses, quantum-chemical calculations, and X-ray crystallography. These heterodimers exhibit a characteristic 2-oxaspiro[4.5]decan-1-one structural motif, biosynthetically formed through intermolecular [4 + 2]-cycloaddition between a germacrane-type sesquiterpene and an ocimene-type monoterpene. The majority of the isolated compounds demonstrated significant anti-neuroinflammatory effects in lipopolysaccharide (LPS)-induced BV-2 microglial cells by reducing the production of pro-inflammatory mediators, specifically tumor necrosis factor-α (TNF-α) and nitric oxide (NO). Further investigation revealed that the lirispirolides' inhibition of NO release correlated with decreased messenger ribonucleic acid (mRNA) expression of inducible NO synthase (iNOS).
Sesquiterpenes/isolation & purification* ; Anti-Inflammatory Agents/isolation & purification* ; Animals ; Mice ; Tumor Necrosis Factor-alpha/genetics* ; Nitric Oxide/immunology* ; Microglia/immunology* ; Molecular Structure ; Liriodendron/chemistry* ; Monoterpenes/isolation & purification* ; Plants, Medicinal/chemistry* ; Cell Line ; Lipopolysaccharides ; Nitric Oxide Synthase Type II/immunology* ; Plant Extracts/pharmacology* ; China