Mechanical trauma injury is a severe insult to neural cells. Subsequent secondary injury involves the release of inflammatory factors that have dramatic consequences for undamaged cells, leading to normal cell death after the initial injury. The present study investigated the capacity for arctigenin (ARC) to prevent secondary effects and evaluated the mechanism underlying the action of microRNA (miRNA)-199a and miRNA-16 in a mechanical trauma injury (MTI) model using SH-SY5Y cells in vitro. SH-SY5Y cells are often applied to in vitro models of neuronal function and differentiation. Recently, miRNAs have been demonstrated to play a crucial role in NF-κB and cholinergic signaling, which can regulate inflammation. The cell model was established by scratch-induced injury of human SH-SY5Y cells, which mimics the characteristics of MTI. A cell counting kit-8 (CCK-8), terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), and immunocytochemistry were used to measure cell viability. Enzyme-linked immunosorbent assay (ELISA) was used to evaluate the inflammatory cytokine and cholinesterase (CHE) content. The lactate dehydrogenase (LDH) content was measured to assess the degree of cell injury. The mRNA levels were measured by RT-PCR to analyze ARC's mechanism of action. miRNA inhibitors and mimics were used to inhibit and strengthen the expression of miRNAs. Protein expression was detected by western blotting analysis. ARC treatment reduced the TNF-α and IL-6 levels as well as the number of TUNEL+ apoptotic SH-SY5Y cells surrounding the scratch and increased the IL-10 level compared to the controls. ARC attenuated the increase of the cell damage degree and LDH content induced by scratching, indicating increased cell survival. Mechanistic studies showed that ARC upregulated the miRNA-16 and miRNA-199a levels to reduce upstream protein (IKKα and IKKβ) expression and inhibit NF-κB signaling pathway activity; moreover, the increased miRNA-199a suppresses cholinesterases to increase cholinergic signaling, resulting in decreased expression of proinflammatory cytokines. ARC treatment confers protection for SH-SY5Y cells through positive regulation of miRNA expression, thereby reducing the inflammatory response. In turn, these effects accelerate injury repair in the scratch-induced injury model. These results might provide insights into the pharmacological role of ARC in anti-inflammation and neuroprotection in neural cells.

The therapeutic potential of adult neural stem cells (NSCs)-derived from bone marrow (BM) has been recently described in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis; however, the beneficial effects are modest due to their marginal anti-inflammatory capacity. To overcome this weakness and endow BM-NSC therapy with profound anti-inflammatory capacity, in this study we pretreated EAE mice with osthole, a natural coumarin with a broad spectrum of pharmacological activities, including anti-inflammation, immunomodulation, and neuroprotection, before NSC-application and continued throughout the study. We found that osthole conferred a potent anti-inflammatory capacity to this BM-NSC therapy, thus more profoundly suppressing ongoing EA and exhibiting significant advantages over conventional NSC-therapy as follows: 1) Enhanced anti-inflammatory effect, thus improving survival environment for engrafted BM-NSCs and protecting myelin sheaths from further demyelination; 2)Drove transplanted (exogenous) BM-NSCs to differentiate into more oligodendrocytes and neurons but inhibited differentiation into astrocytes, thus promoting remyelination and axonal growth, and reducing astrogliosis; and 3) augmented CNS neurotrophic support thus promoted resident (endogenous) repair of myelin/axonal damage. These effects make the BM-NSCs-based therapy a more promising approach to enhance remyelination and neuronal repopulation, thus more effectively promoting anatomic and functional recovery from neurological deficits.

Accumulation of β-amyloid peptide (Aβ) in the brain plays an important role in the pathogenesis of Alzheimer's disease (AD). It has been reported that osthole exerts its neuroprotective effect on neuronal synapses, but its exact mechanism is obscure. Recently, microRNAs have been demonstrated to play a crucial role in inducing synaptotoxicity by Aβ, implying that targeting microRNAs could be a therapeutic approach of AD. In the present study, we investigated the neuroprotective effects of osthole on a cell model of AD by transducing APP695 Swedish mutant (APP695swe, APP) into mouse cortical neurons and human SH-SY5Y cells. In this study, the cell counting kit CCK-8, apoptosis assay, immunofluorescence analysis, enzyme-linked immunosorbent assay (ELISA), quantitative real-time polymerase chain reaction, and Western blot assay were used. We found that osthole could enhance cell viability, prevent cell death, and reverse the reduction of synaptic proteins (synapsin-1, synaptophysin, and postsynaptic density-95) in APP-overexpressed cells, which was attributed to increases in microRNA-9 (miR-9) expression and subsequent decreases in CAMKK2 and p-AMPKα expressions. These results demonstrated that osthole plays a neuroprotective activity role in part through upregulating miR-9 in AD.

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SummaryThe nature of pathogenic mechanisms associated with the development of multiple sclerosis (MS) have long been debated. However, limited research was conducted to define the interplay between infiltrating lymphocytes and resident cells of the central nervous system (CNS). Data presented in this report describe a novel role for astrocyte-mediated alterations to myelin oligodendrocyte glycoprotein (MOG)35-55-specific lymphocyte responses, elicited during the development of experimental autoimmune encephalitomyelitis (EAE). In-vitro studies demonstrated that astrocytes inhibited the proliferation and interferon (IFN)-g, interleukin (IL)-4, IL-17 and transforming growth factor (TGF)-b secretion levels of MOG35-55-specific lymphocytes, an effect that could be ameliorated by astrocyte IL-27 neutralization. However, when astrocytes were pretreated with IFN-g, they could promote the proliferation and secretion levels of MOG35-55-specific lymphocytes, coinciding with apparent expression of major histocompatibility complex (MHC)-II on astrocytes themselves. Quantitative polymerase chain reaction (qPCR) demonstrated that production of IL-27 in the spinal cord was at its highest during the initial phases. Conversely, production of IFN-g in the spinal cord was highest during the peak phase. Quantitative analysis of MHC-II expression in the spinal cord showed that there was a positive correlation between MHC-II expression and IFN-g production. In addition, astrocyte MHC-II expression levels correlated positively with IFN-g production in the spinal cord. These findings suggested that astrocytes might function as both inhibitors and promoters of EAE. Astrocytes prevented MOG35-55-specific lymphocyte function by secreting IL-27 during the initial phases of EAE. Then, in the presence of higher IFN-g levels in the spinal cord, astrocytes were converted into antigen-presenting cells. This conversion might promote the progression of pathological damage and result in a peak of EAE severity.

Convection enhanced delivery (CED) infuses drugs directly into brain tissue. Needle insertion is required and results in a stab wound injury (SWI). Subsequent secondary injury involves the release of inflammatory and apoptotic cytokines, which have dramatic consequences on the integrity of damaged tissue, leading to the evolution of a pericontusional-damaged area minutes to days after in the initial injury. The present study investigated the capacity for arctigenin (ARC) to prevent secondary brain injury and the determination of the underlying mechanism of action in a mouse model of SWI that mimics the process of CED. After CED, mice received a gavage of ARC from 30 min to 14 days. Neurological severity scores (NSS) and wound closure degree were assessed after the injury. Histological analysis and immunocytochemistry were used to evaluated the extent of brain damage and neuroinflammation. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) was used to detect universal apoptosis. Enzyme-linked immunosorbent assays (ELISA) was used to test the inflammatory cytokines (tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-10) and lactate dehydrogenase (LDH) content. Gene levels of inflammation (TNF-α, IL-6, and IL-10) and apoptosis (Caspase-3, Bax and Bcl-2) were detected by reverse transcription-polymerase chain reaction (RT-PCR). Using these, we analyzed ARC’s efficacy and mechanism of action. Results: ARC treatment improved neurological function by reducing brain water content and hematoma and accelerating wound closure relative to untreated mice. ARC treatment reduced the levels of TNF-α and IL-6 and the number of allograft inflammatory factor (IBA)- and myeloperoxidase (MPO)-positive cells and increased the levels of IL-10. ARC-treated mice had fewer TUNEL+ apoptotic neurons and activated caspase-3-positive neurons surrounding the lesion than controls, indicating increased neuronal survival. Conclusions: ARC treatment confers neuroprotection of brain tissue through anti-inflammatory and anti-apoptotic effects in a mouse model of SWI. These results suggest a new strategy for promoting neuronal survival and function after CED to improve long-term patient outcome.

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