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Introduction: The immune system's defense against pathogens involves innate and adaptive responses, crucial in maintaining overall health. Immunosuppressed states render individuals more susceptible to potential diseases, indicating the need for effective strategies to bolster immune functions. Objectives: Although the immunostimulatory effects of various probiotics have been studied, the specific effects and molecular mechanisms of Lactococcus lactis OTG1204 (OTG1204) remain unknown. In this study, the aim was to investigate the molecular mechanisms of OTG1204 in RAW 264.7 macrophages, the key effector cells of the innate immune system involved in host defense and inflammatory responses. Additionally, in this study, the effects of OTG1204 on cyclophosphamide (CTX)-induced immunosuppression states were investigated, thereby demonstrating its potential as an immune stimulant. Methods: To assess the macrophage activation ability and underlying mechanisms of OTG1204, RAW 264.7 cells were utilized with transfection, enzyme-linked immunosorbent assay, and quantitative real-time PCR analyses. Furthermore, to evaluate the immunostimulatory effects under immunosuppressed conditions, CTX-induced immunosuppression mice model was employed, and analyses were performed using hematoxylin and eosin staining, flow cytometry, and microbiota examination. Results: OTG1204 activated RAW 264.7 macrophages, leading to increased production of nitric oxide, prostaglandin E2, and cytokines. This immune activation was mediated through the upregulation of toll-like receptor 2, which subsequently activated the nuclear factor-κB (NF-kB) and mitogen-activated protein kinase (MAPK)/activator protein 1 (AP-1) pathways, thereby stimulating the immune response. In CTX-treated mice, OTG1204 recovered body weight, spleen, and mesenteric lymph node indices, and natural killer cell activity. It re-established populations of innate and adaptive immune cells and activated T cells to secrete cytokines. We also examined the gut barrier integrity and microbiota composition to assess OTG1204's impact on intestinal health, as these factors play a significant role in immune enhancement. OTG1204 enhanced gut barrier integrity by upregulating mucin 2 and tight junction proteins and modulated the gut microbiota by restoring the Firmicutes/Bacteroidetes balance and reducing the abundance of Actinobacteria and Tenericutes. Conclusion: These results suggest that OTG1204 may serve as an effective probiotic for immune enhancement and gut health management by targeting the NF-κB and MAPK/AP-1 pathways, with minimal side effects. [ABSTRACT FROM AUTHOR]

Aims: Cognitive impairment is associated with reduced hippocampal neurogenesis; however, the causes of decreased hippocampal neurogenesis remain highly controversial. Here, we investigated the role of survivin in the modulation of hippocampal neurogenesis in AD. Methods: To investigate the effect of survivin on neurogenesis in neural stem cells (NSCs), we treated mouse embryonic NSCs with a survivin inhibitor (YM155) and adeno‐associated viral survivin (AAV‐Survivin). To explore the potential role of survivin expression in AD, AAV9‐Survivin or AAV9‐GFP were injected into the dentate gyrus (DG) of hippocampus of 7‐month‐old wild‐type and 5XFAD mice. Cognitive function was measured by the Y maze and Morris water maze. Neurogenesis was investigated by BrdU staining, immature, and mature neuron markers. Results: Our results indicate that suppression of survivin expression resulted in decreased neurogenesis. Conversely, overexpression of survivin using AAV‐Survivin restored neurogenesis in NSCs that had been suppressed by YM155 treatment. Furthermore, the expression level of survivin decreased in the 9‐month‐old 5XFAD compared with that in wild‐type mice. AAV‐Survivin‐mediated overexpression of survivin in the DG in 5XFAD mice enhanced neurogenesis and cognitive function. Conclusion: Hippocampal neurogenesis can be enhanced by survivin overexpression, suggesting that survivin could serve as a promising therapeutic target for the treatment of AD. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is the most common neurodegenerative disease characterized by amyloid‐β (Aβ) deposition, accompanied by neuroinflammation and memory dysfunction. Houttuyniae Herba (aerial parts of Houttuynia cordata, also known as fish mint; HH), an herbal medicine traditionally used to treat fever, urinary disorders, and pus, is revealed to protect neurons from Aβ toxicity and regulate cholinergic dysfunction in AD models. In this study, we aimed to investigate the effects of HH on excessive accumulation of Aβ followed by neuroinflammation, synaptic degeneration, and memory impairment. Two‐month‐old 5xFAD transgenic mice were administered HH at 100 mg/kg for 4 months. We observed that HH treatment ameliorated memory impairment and reduced Aβ deposits in the brains of the mice. HH directly inhibited Aβ aggregation in vitro using the Thioflavin T assay and indirectly suppressed the amyloidogenic pathway by increasing alpha‐secretase expression in the mice brain. In addition, HH exerted antineuroinflammatory effects by reducing of glial activation and p38 phosphorylation. Moreover, HH treatment increased the expression of synaptophysin, a presynaptic marker protein. Overall, HH alleviates memory impairment in AD by facilitating nonamyloidogenic pathway and inhibiting neuroinflammation. Therefore, we suggest that HH can be a promising herbal drug for patients with AD requiring multifaceted improvement. [ABSTRACT FROM AUTHOR]

Oxidative catabolism of monoamine neurotransmitters by monoamine oxidases (MAOs) produces reactive oxygen species (ROS), which contributes to neuronal cells' death and also lowers monoamine neurotransmitter levels. In addition, acetylcholinesterase activity and neuroinflammation are involved in neurodegenerative diseases. Herein, we aim to achieve a multifunctional agent that inhibits the oxidative catabolism of monoamine neurotransmitters and, hence, the detrimental production of ROS while enhancing neurotransmitter levels. Such a multifunctional agent might also inhibit acetylcholinesterase and neuroinflammation. To meet this end goal, a series of aminoalkyl derivatives of analogs of the natural product hispidol were designed, synthesized, and evaluated against both monoamine oxidase-A (MAO-A) and monoamine oxidase-B (MAO-B). Promising MAO inhibitors were further checked for the inhibition of acetylcholinesterase and neuroinflammation. Among them, compounds 3aa and 3bc were identified as potential multifunctional molecules eliciting submicromolar selective MAO-B inhibition, low-micromolar AChE inhibition, and the inhibition of microglial PGE2 production. An evaluation of their effects on memory and cognitive impairments using a passive avoidance test confirmed the in vivo activity of compound 3bc, which showed comparable activity to donepezil. In silico molecular docking provided insights into the MAO and acetylcholinesterase inhibitory activities of compounds 3aa and 3bc. These findings suggest compound 3bc as a potential lead for the further development of agents against neurodegenerative diseases. [ABSTRACT FROM AUTHOR]

Amyloid beta (Aβ)-induced abnormal neuroinflammation is recognized as a major pathological factor of Alzheimer's disease (AD), which results in memory impairment. Inhibition of excessive neuroinflammation mediated by Aβ is considered a promising strategy to ameliorate AD symptoms. To regulate the inflammatory response, nutritional and dietary supplements have been used for centuries. Based on this idea, we investigated whether MBN, a novel nutritional mixture including cassia bark, turmeric root, and ginkgo leaf, can prevent AD progression through neuroinflammatory regulation. MBN (10, 30, or 100 μg/ml) and Aβ1-42 monomer were incubated together, and the degree of Aβ aggregation was measured using Thioflavin T assay. The effects of MBN on Aβ pathology in vivo were evaluated by orally administering MBN (40 mg/kg/day for 16 weeks) to five familial AD (5xFAD) mice. We found that treatment with MBN inhibited Aβ aggregation in vitro. Next, MBN treatment significantly inhibited the activation of microglia induced by aggregated Aβ in 5xFAD mice. Caspase-1 activation, which plays an important role in the maturation of interleukin-1β, was markedly reduced by MBN. We also found that oral administration of MBN in 5xFAD mice alleviated memory decline. Taken together, our findings demonstrate that MBN suppresses neuroinflammation by downregulating the caspase-1 expression, thereby ameliorating memory impairment in 5xFAD mice. Based on these results, we suggest that MBN may be a preventive and therapeutic supplement for AD through the regulation of neuroinflammation. [ABSTRACT FROM AUTHOR]