Anti-inflammatory and anti-amyloidogenic effects of a small molecule, 2,4-bis(p-hydroxyphenyl)-2-butenal in Tg2576 Alzheimer's disease mice model

What Threshold of Amyloid Reduction Is Necessary to Meaningfully Improve Cognitive Function in Transgenic Alzheimer's Disease Mice?

Background

Amyloid-β plaques (Aβ) are associated with Alzheimer's disease (AD). Pooled assessment of amyloid reduction in transgenic AD mice is critical for expediting anti-amyloid AD therapeutic research.

Objective

The mean threshold of Aβ reduction necessary to achieve cognitive improvement was measured via pooled assessment (n = 594 mice) of Morris water maze (MWM) escape latency of transgenic AD mice treated with substances intended to reduce Aβ via reduction of beta-secretase cleaving enzyme (BACE).

Methods

Machine learning and statistical methods identified necessary amyloid reduction levels using mouse data (e.g., APP/PS1, LPS, Tg2576, 3xTg-AD, control, wild type, treated, untreated) curated from 22 published studies.

Results

K-means clustering identified 4 clusters that primarily corresponded with level of Aβ: untreated transgenic AD control mice, wild type mice, and two clusters of transgenic AD mice treated with BACE inhibitors that had either an average 25% "medium reduction" of Aβ or 50% "high reduction" of Aβ compared to untreated control. A 25% Aβ reduction achieved a 28% cognitive improvement, and a 50% Aβ reduction resulted in a significant 32% improvement compared to untreated transgenic mice (p < 0.05). Comparatively, wild type mice had a mean 41% MWM latency improvement over untreated transgenic mice (p < 0.05). BACE reduction had a lesser impact on the ratio of Aβ42 to Aβ40. Supervised learning with an 80% -20% train-test split confirmed Aβ reduction was a key feature for predicting MWM escape latency (R2 = 0.8 to 0.95).

Conclusions

Results suggest a 25% reduction in Aβ as a meaningful treatment threshold for improving transgenic AD mouse cognition.

(E)-2-methoxy-4-(3-(4-methoxyphenyl)prop-1-en-1-yl)phenol alleviates inflammatory responses in LPS-induced mice liver sepsis through inhibition of STAT3 phosphorylation

Sepsis is a life-threatening disease with limited treatment options, and the inflammatory process represents an important factor affecting its progression. Many studies have demonstrated the critical roles of signal transducer and activator of transcription 3 (STAT3) in sepsis pathophysiology and pro-inflammatory responses. Inhibition of STAT3 activity may therefore represent a promising treatment option for sepsis. We here used a mouse model to demonstrate that (E)-2-methoxy-4-(3-(4-methoxyphenyl)prop-1-en-1-yl)phenol (MMPP) treatment prevented the liver sepsis-related mortality induced by 30 mg/kg lipopolysaccharide (LPS) treatment and reduced LPS-induced increase in alanine transaminase, aspartate transaminase, and lactate dehydrogenase levels, all of which are markers of liver sepsis progression. These recovery effects were associated with decreased LPS-induced STAT3, p65, and JAK1 phosphorylation and proinflammatory cytokine (interleukin 1 beta, interleukin 6, and tumor necrosis factor alpha) level; expression of cyclooxygenase-2 and induced nitric oxide synthase were also reduced by MMPP. In an in vitro study using the normal liver cell line THLE-2, MMPP treatment prevented the LPS-induced increase of STAT3, p65, and JAK1 phosphorylation and inflammatory protein expression in a dose-dependent manner, and this effect was enhanced by combination treatment with MMPP and STAT3 inhibitor. The results clearly indicate that MMPP treatment prevents LPS-induced mortality by inhibiting the inflammatory response via STAT3 activity inhibition. Thus, MMPP represents a novel agent for alleviating LPS-induced liver sepsis.

Inflammatory signaling pathways in the treatment of Alzheimer's disease with inhibitors, natural products and metabolites (Review)

The intricate nature of Alzheimer's disease (AD) pathogenesis poses a persistent obstacle to drug development. In recent times, neuroinflammation has emerged as a crucial pathogenic mechanism of AD, and the targeting of inflammation has become a viable approach for the prevention and management of AD. The present study conducted a comprehensive review of the literature between October 2012 and October 2022, identifying a total of 96 references, encompassing 91 distinct pharmaceuticals that have been investigated for their potential impact on AD by inhibiting neuroinflammation. Research has shown that pharmaceuticals have the potential to ameliorate AD by reducing neuroinflammation mainly through regulating inflammatory signaling pathways such as NF‑κB, MAPK, NLRP3, PPARs, STAT3, CREB, PI3K/Akt, Nrf2 and their respective signaling pathways. Among them, tanshinone IIA has been extensively studied for its anti‑inflammatory effects, which have shown significant pharmacological properties and can be applied clinically. Thus, it may hold promise as an effective drug for the treatment of AD. The present review elucidated the inflammatory signaling pathways of pharmaceuticals that have been investigated for their therapeutic efficacy in AD and elucidates their underlying mechanisms. This underscores the auspicious potential of pharmaceuticals in ameliorating AD by impeding neuroinflammation.

Anti-Inflammatory Properties of Plants from Serbian Traditional Medicine

Inflammation is a natural protective response of the human body to a variety of hostile agents and noxious stimuli. Standard anti-inflammatory therapy includes drugs whose usage is associated with a number of side effects. Since ancient times, natural compounds have been used for the treatment of inflammation. Traditionally, the use of medicinal plants is considered safe, inexpensive, and widely acceptable. In Serbia, traditional medicine, based on the strong belief in the power of medicinal herbs, is the widespread form of treatment. This is supported by the fact that Serbia is classified as one of 158 world centers of biodiversity, which confirms that this country is a treasure of medicinal herbs. Some of the most used herbs for the treatment of inflammations of various causes in Serbian tradition are yarrow, common agrimony, couch grass, onion, garlic, marshmallow, common birch, calendula, liquorice, walnut, St. John’s wort, chamomile, peppermint, white willow, sage, and many others. The biological activity and anti-inflammatory effect of selected plants are attributed to different groups of secondary biomolecules such as flavonoids, phenolic acids, sterols, terpenoids, sesquiterpenes, and tannins. This paper provides an overview of plants with traditional anti-inflammatory use in Serbia with reference to available studies that examined this effect. Plants used in traditional medicine could be a powerful source for the development of new remedies. Therefore intensive research on the bioactive potential of medicinal plants in each region should be the focus of scientists around the world.

The Phytochemistry and Pharmacology of Tulbaghia, Allium, Crinum and Cyrtanthus: ‘Talented’ Taxa from the Amaryllidaceae

Amaryllidaceae is a significant source of bioactive phytochemicals with a strong propensity to develop new drugs. The genera Allium, Tulbaghia, Cyrtanthus and Crinum biosynthesize novel alkaloids and other phytochemicals with traditional and pharmacological uses. Amaryllidaceae biomolecules exhibit multiple pharmacological activities such as antioxidant, antimicrobial, and immunomodulatory effects. Traditionally, natural products from Amaryllidaceae are utilized to treat non-communicable and infectious human diseases. Galanthamine, a drug from this family, is clinically relevant in treating the neurocognitive disorder, Alzheimer’s disease, which underscores the importance of the Amaryllidaceae alkaloids. Although Amaryllidaceae provide a plethora of biologically active compounds, there is tardiness in their development into clinically pliable medicines. Other genera, including Cyrtanthus and Tulbaghia, have received little attention as potential sources of promising drug candidates. Given the reciprocal relationship of the increasing burden of human diseases and limited availability of medicinal therapies, more rapid drug discovery and development are desirable. To expedite clinically relevant drug development, we present here evidence on bioactive compounds from the genera Allium, Tulgbaghia, Cyrtanthus and Crinum and describe their traditional and pharmacological applications.

Chemical Composition and Agronomic Traits of Allium sativum and Allium ampeloprasum Leaves and Bulbs and Their Action against Listeria monocytogenes and Other Food Pathogens

In this work, we aimed to study the chemical composition of the essential oils from bulbs and leaves of two cultivars of Allium sativum L. and two of A. ampeloprasum L. var. holmense. Moreover, we investigated their activity against four common bacterial strains responsible for food contamination (Listeria monocytogenes, Escherichia coli, Acinetobacter baumannii, and Staphylococcus aureus) by formation of biofilms. The susceptibility of bacterial biofilms was evaluated by crystal violet assay, whereas the metabolic changes occurring in the bacterial cells were ascertained through the MTT test. The essential oils were characterized by the presence of most characteristic components, although with different composition between the species and the cultivars. The essential oils inhibited the capacity of the pathogenic bacteria to form biofilms (up to 79.85 against L. monocytogenes) and/or acted on their cell metabolism (with inhibition of 68.57% and 68.89% against L. monocytogenes and S. aureus, respectively). The capacity of the essential oils to act against these foodborne bacteria could suggests further ideas for industrial applications and confirms the versatility of these essential oils as food preservatives.

Physalin B reduces Aβ secretion through down-regulation of BACE1 expression by activating FoxO1 and inhibiting STAT3 phosphorylation

Physalin B (PB), one of the major active steroidal constituents of Solanaceae Physalis plants, has a wide variety of biological activities. We found that PB significantly down-regulated β-amyloid (Aβ) secretion in N2a/APPsw cells. However, the underlying mechanisms are not well understood. In the current study, we investigated the changes in key enzymes involved in β-amyloid precursor protein (APP) metabolism and other APP metabolites by treating N2a/APPsw cells with PB at different concentrations. The results indicated that PB reduced Aβ secretion, which was caused by down-regulation of β-secretase (BACE1) expression, as indicated at both the protein and mRNA levels. Further research revealed that PB regulated BACE1 expression by inducing the activation of forkhead box O1 (FoxO1) and inhibiting the phosphorylation of signal transducer and activator of transcription 3 (STAT3). In addition, the effect of PB on BACE1 expression and Aβ secretion was reversed by treatment with FoxO1 siRNA and STAT3 antagonist S3I-201. In conclusion, these data demonstrated that PB can effectively down-regulate the expression of BACE1 to reduce Aβsecretion by activating the expression of FoxO1 and inhibiting the phosphorylation of STAT3.

Activation of Inflammation is Associated with Amyloid-β Accumulation Induced by Chronic Sleep Restriction in Rats

Alzheimer's disease (AD) is the most common age-associated neurodegenerative disease featured by progressive learning and memory deficit, and Aβ was identified as playing a key role in the process of AD and was theorized to be caused by the imbalance of production and clearance. Increasing evidence suggested an association between sleep deprivation and AD. Our recent study found that chronic sleep restriction (CSR) caused cognitive impairment and Aβ accumulation in rats, but the underlining mechanism was unclear. In the present study, we investigated the effects of inflammation on Aβ accumulation induced by CSR. We found that CSR significantly increased the expression of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), inducible nitric oxide synthase (iNOS), and nitric oxide (NO) in brain, and the inflammatory factors levels were positively correlated with Aβ42 deposition. Additionally, the inflammatory factors were correlated with BACE1, LRP-1, and RAGE levels in both the hippocampus and the prefrontal cortex. Furthermore, the plasma levels of IL-1β, TNF-α, and NO were elevated after CSR, and the concentration of plasma inflammatory mediators were correlated with plasma levels of sLRP1 and sRAGE. These results suggested that the inflammation in brain and plasma might be involved in the CSR-induced Aβ accumulation.

Multi-Target Drug Candidates for Multifactorial Alzheimer's Disease: AChE and NMDAR as Molecular Targets

Alzheimer's disease (AD) is one of the most common forms of dementia among elder people, which is a progressive neurodegenerative disease that results from a chronic loss of cognitive activities. It has been observed that AD is multifactorial, hence diverse pharmacological targets that could be followed for the treatment of AD. The Food and Drug Administration has approved two types of medications for AD treatment such as cholinesterase inhibitors (ChEIs) and N-methyl-D-aspartic acid receptor (NMDAR) antagonists. Rivastigmine, donepezil, and galantamine are the ChEIs that have been approved to treat AD. On the other hand, memantine is the only non-competitive NMDAR antagonist approved in AD treatment. As compared with placebo, it has been revealed through clinical studies that many single-target therapies are unsuccessful to treat multifactorial Alzheimer's symptoms or disease progression. Therefore, due to the complex nature of AD pathophysiology, diverse pharmacological targets can be hunted. In this article, based on the entwined link of acetylcholinesterase (AChE) and NMDAR, we represent several multifunctional compounds in the rational design of new potential AD medications. This review focus on the significance of privileged scaffolds in the generation of the multi-target lead compound for treating AD, investigating the idea and challenges of multi-target drug design. Furthermore, the most auspicious elementary units for designing as well as synthesizing hybrid drugs are demonstrated as pharmacological probes in the rational design of new potential AD therapeutics.

Recent Studies on Design and Development of Drugs Against Alzheimer's Disease (AD) Based on Inhibition of BACE-1 and Other AD-causative Agents

BACKGROUND

Alzheimer's disease (AD) is one of the neurodegenerative diseases and has been hypothesized to be a protein misfolding disease. In the generation of AD, β-secretase, γ-secretase, and tau protein play an important role. A literature search reflects ever increasing interest in the design and development of anti-AD drugs targeting β-secretase, γ-secretase, and tau protein.

OBJECTIVE

The objective is to explore the structural aspects and role of β-secretase, γ-secretase, and tau protein in AD and the efforts made to exploit them for the design of effective anti-AD drugs.

METHODS

The manuscript covers the recent studies on design and development of anti-AD drugs exploiting amyloid and cholinergic hypotheses.

RESULTS

Based on amyloid and cholinergic hypotheses, effective anti-AD drugs have been searched out in which non-peptidic BACE1 inhibitors have been most prominent.

CONCLUSION

Further exploitation of the structural aspects and the inhibition mechanism for β-secretase, γ-secretase, and tau protein and the use of cholinergic hypothesis may lead still more potent anti-AD drugs.

Wasef L, Elewa YHA, A. Al-Sagan A, Abd El-Hack ME, Taha AE, M. Abd-Elhakim Y, Prasad Devkota H. Chemical Constituents and Pharmacological Activities of Garlic (Allium sativum L.): A Review

Medicinal plants have been used from ancient times for human healthcare as in the form of traditional medicines, spices, and other food components. Garlic (Allium sativum L.) is an aromatic herbaceous plant that is consumed worldwide as food and traditional remedy for various diseases. It has been reported to possess several biological properties including anticarcinogenic, antioxidant, antidiabetic, renoprotective, anti-atherosclerotic, antibacterial, antifungal, and antihypertensive activities in traditional medicines. A. sativum is rich in several sulfur-containing phytoconstituents such as alliin, allicin, ajoenes, vinyldithiins, and flavonoids such as quercetin. Extracts and isolated compounds of A. sativum have been evaluated for various biological activities including antibacterial, antiviral, antifungal, antiprotozoal, antioxidant, anti-inflammatory, and anticancer activities among others. This review examines the phytochemical composition, pharmacokinetics, and pharmacological activities of A. sativum extracts as well as its main active constituent, allicin.

Cholinesterase inhibitors as Alzheimer's therapeutics (Review)

Alzheimer's disease (AD) is one of the most common forms of dementia. AD is a chronic syndrome of the central nervous system that causes a decline in cognitive function and language ability. Cholinergic deficiency is associated with AD, and various cholinesterase inhibitors have been developed for the treatment of AD, including naturally‑derived inhibitors, synthetic analogues and hybrids. Currently, the available drugs for AD are predominantly cholinesterase inhibitors. However, the efficacy of these drugs is limited as they may cause adverse side effects and are not able to completely arrest the progression of the disease. Since AD is multifactorial disease, dual and multi‑target inhibitors have been developed. The clinical applications and the limitations of the inhibitors used to treat AD are discussed in the present review. Additionally, this review presents the current status and future directions for the development of novel drugs with reduced toxicity and preserved pharmacological activity.

(E)-2-methoxy-4-(3-(4-methoxyphenyl) prop-1-en-1-yl) Phenol Ameliorates MPTP-Induced Dopaminergic Neurodegeneration by Inhibiting the STAT3 Pathway

Neuroinflammation is implicated in dopaminergic neurodegeneration. We have previously demonstrated that (E)-2-methoxy-4-(3-(4-methoxyphenyl) prop-1-en-1-yl) phenol (MMPP), a selective signal transducer and activator of transcription 3 (STAT3) inhibitor, has anti-inflammatory properties in several inflammatory disease models. We investigated whether MMPP could protect against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced dopaminergic cell loss and behavioral impairment. Imprinting control region (ICR) mice (8 weeks old, n = 10 per group) were administered MMPP (5 mg/kg) in drinking water for 1 month, and injected with MPTP (15 mg/kg, four times with 2 h intervals) during the last 7 days of treatment. MMPP decreased MPTP-induced behavioral impairments in rotarod, pole, and gait tests. We also showed that MMPP ameliorated dopamine depletion in the striatum and inflammatory marker elevation in primary cultured neurons by high-performance liquid chromatography and immunohistochemical analysis. Increased activation of STAT3, p38, and monoamine oxidase B (MAO-B) were observed in the substantia nigra and striatum after MPTP injection, effects that were attenuated by MMPP treatment. Furthermore, MMPP inhibited STAT3 activity and expression of neuroinflammatory proteins, including ionized calcium binding adaptor molecule 1 (Iba1), inducible nitric oxide synthase (iNOS), and glial fibrillary acidic protein (GFAP) in 1-methyl-4-phenylpyridinium (MPP⁺; 0.5 mM)-treated primary cultured cells. However, mitogen-activated protein kinase (MAPK) inhibitors augmented the activity of MMPP. Collectively, our results suggest that MMPP may be an anti-inflammatory agent that attenuates dopaminergic neurodegeneration and neuroinflammation through MAO-B and MAPK pathway-dependent inhibition of STAT3 activation.

Chronic Sleep Restriction Induces Aβ Accumulation by Disrupting the Balance of Aβ Production and Clearance in Rats

Amyloid-β (Aβ) plays an important role in Alzheimer's disease (AD) pathogenesis, and growing evidence has shown that poor sleep quality is one of the risk factors for AD, but the mechanisms of sleep deprivation leading to AD have still not been fully demonstrated. In the present study, we used wild-type (WT) rats to determine the effects of chronic sleep restriction (CSR) on Aβ accumulation. We found that CSR-21d rats had learning and memory functional decline in the Morris water maze (MWM) test. Meanwhile, Aβ₄₂ deposition in the hippocampus and the prefrontal cortex was high after a 21-day sleep restriction. Moreover, compared with the control rats, CSR rats had increased expression of β-site APP-cleaving enzyme 1 (BACE1) and sAPPβ and decreased sAPPα levels in both the hippocampus and the prefrontal cortex, and the BACE1 level was positively correlated with the Aβ₄₂ level. Additionally, in CSR-21d rats, low-density lipoprotein receptor-related protein 1 (LRP-1) levels were low, while receptor of advanced glycation end products (RAGE) levels were high in the hippocampus and the prefrontal cortex, and these transporters were significantly correlated with Aβ₄₂ levels. In addition, CSR-21d rats had decreased plasma Aβ₄₂ levels and soluble LRP1 (sLRP1) levels compared with the control rats. Altogether, this study demonstrated that 21 days of CSR could lead to brain Aβ accumulation in WT rats. The underlying mechanisms may be related to increased Aβ production via upregulation of the BACE1 pathway and disrupted Aβ clearance affecting brain and peripheral Aβ transport.

Molecular docking studies of coumarin hybrids as potential acetylcholinesterase, butyrylcholinesterase, monoamine oxidase A/B and β-amyloid inhibitors for Alzheimer's disease

Coumarins are the phytochemicals, which belong to the family of benzopyrone, that display interesting pharmacological properties. Several natural, synthetic and semisynthetic coumarin derivatives have been discovered in decades for their applicability as lead structures as drugs. Coumarin based conjugates have been described as potential AChE, BuChE, MAO and β-amyloid inhibitors. Therefore, the objective of this review is to focus on the construction of these pharmacologically important coumarin analogues with anti-Alzheimer’s activities, highlight their docking studies and structure–activity relationships based on their substitution pattern with respect to the selected positions on the chromen ring by emphasising on the research reports conducted in between year 1968 to 2017.

MiR-34a and stroke: Assessment of non-modifiable biological risk factors in cerebral ischemia

Aging of the nervous system, and the occurrence of age-related brain diseases such as stroke, are associated with changes to a variety of cellular processes controlled by many distinct genes. MicroRNAs (miRNAs), short non-coding functional RNAs that can induce translational repression or site-specific cleavage of numerous target mRNAs, have recently emerged as important regulators of cellular senescence, aging, and the response to neurological insult. Here, we focused on the assessment of the role of miR-34a in stroke. We noted increases in miR-34a expression in the blood of stroke patients as well as in blood and brain of mice subjected to experimental stroke. Our methodical genetic manipulation of miR-34a expression substantially impacted stroke-associated preclinical outcomes and we have in vitro evidence that these changes may be driven at least in part by disruptions to blood brain barrier integrity and mitochondrial oxidative phosphorylation in endothelial cells. Finally, aging, independent of brain injury, appears to be associated with shifts in circulating miRNA profiles. Taken together, these data support a role for miRNAs, and specifically miR-34a, in brain aging and the physiological response to age-related neurological insult, and lay the groundwork for future investigation of this novel therapeutic target.

Estrogen deficiency exacerbates Aβ-induced memory impairment through enhancement of neuroinflammation, amyloidogenesis and NF-ĸB activation in ovariectomized mice

Estrogen is well known to have a preventative effect in Alzheimer's disease (AD) pathology. Several studies have demonstrated that nuclear factor kappa-B (NF-ĸB) can contribute to the effects of estrogen on the development of AD. We investigated whether NF-ĸB affects amyloid-beta (Aβ)-induced memory impairment in an estrogen-lacking condition. In the present study, nine-week-old Institute cancer research (ICR) mice were ovariectomized to block estrogen stimulation. Ten weeks after the ovariectomization, mice were administered with Aβ (300 pmol) via intracerebroventricular (ICV) infusion for 2 weeks. Memory impairment, neuroinflammatory protein expression, and amyloidogenic pathways were then measured. Ovariectomized mice demonstrated severe memory impairment, Aβ accumulation, neprilysin downregulation, and activation of NF-ĸB signaling compared to sham-control mice. In vitro experiments demonstrated that β-estradiol (10 μM) inhibited Aβ (1 μM)-induced neuroinflammation in microglial BV-2 cells and prevented Aβ-induced cell death in primary cultured neuronal cells. As in in vivo experiments, NF-ĸB activation was significantly upregulated in in vitro experiments. Furthermore β-estradiol treatment inhibited NF-ĸB activation in both of microglial BV-2 cells and cultured neuronal cells. These findings suggest that estrogen may protect against memory impairment through the regulation of Aβ accumulation and neurogenic inflammation by inhibiting NF-κB activity.

A New Compound Isolated from the Reduced Ribose-Tryptophan Maillard Reaction Products Exhibits Distinct Anti-inflammatory Activity

In this study, a compound of 532.24 Da named BF-4 was separated from the ribose-tryptophan Maillard reaction products by solvent extraction and purified through reverse phase high performance liquid chromatography. The purified compound BF-4 was identified as 3-((1 H-indol-3-yl)methyl)-8-(5-((1 H-indol-3-yl)methyl)-6-oxomorpholin-2-yl)-9-hydroxy-1,7,4-dioxazecan-2-one in accordance with 1D- and 2D-NMR spectra and LC-ESI-MS/MS analysis. BF-4 significantly reduced the production of nitric oxide (NO), interleukin-6 (IL-6), and tumor necrosis factor α (TNF-α) in lipopolysaccharide-stimulated RAW 264.7 cells. It inhibited nuclear factor κB (NF-κB) activation and mitogen-activated protein kinase (MAPK) phosphorylation through suppressing phosphorylation of IκBα, P65, P38 and c-Jun N-terminal kinase (JNK). The anti-inflammatory activity of BF-4 was comparable to dexamethasone, and more importantly, BF-4 showed less cytotoxicity than dexamethasone on the normal human liver cell LO2. The results indicate that BF-4 is a promising anti-inflammatory agent with pharmaceutical potential.

(E)-2-Methoxy-4-(3-(4-methoxyphenyl) prop-1-en-1-yl) Phenol Ameliorates LPS-Mediated Memory Impairment by Inhibition of STAT3 Pathway

Alzheimer’s disease (AD) is pathologically characterized by an excessive accumulation of amyloid-beta (Aβ) fibrils within the brain. We tested the anti-inflammatory and anti-amyloidogenic effects of (E)-2-methoxy-4-(3-(4-methoxyphenyl) prop-1-en-1-yl) phenol (MMPP), a selective signal transducer and activator of transcription 3 (STAT3) inhibitor. We examined whether MMPP (5 mg/kg in drinking water for 1 month) prevents amyloidogenesis and cognitive impairment on AD model mice induced by intraperitoneal LPS (250 μg/kg daily 7 times) injections. Additionally, we investigated the anti-neuroinflammatory and anti-amyloidogenic effect of MMPP (1, 5, and 10 μg/mL) in LPS (1 μg/mL)-treated cultured astrocytes and microglial BV-2 cells. MMPP treatment reduced LPS-induced memory loss. This memory recovery effect was associated with the reduction of LPS-induced inflammatory proteins; cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) as well as activation of microglial cells and astrocytes in the brain. Furthermore, MMPP reduced LPS-induced β-secretase and Aβ generation. In in vitro study, LPS-induced expression of inflammatory proteins and amyloidogenic proteins was decreased in microglial BV-2 cells and cultured astrocytes by MMPP treatment. Moreover, MMPP treatment suppressed DNA binding activities of the activation of STAT3 in in vivo and in vitro. These results indicated that MMPP inhibits LPS-induced amyloidogenesis and neuroinflammation via inhibition of STAT3.

KRICT-9 inhibits neuroinflammation, amyloidogenesis and memory loss in Alzheimer's disease models

Alzheimer's disease (AD) is one of the most common forms of dementia and is characterized by neuroinflammation and amyloidogenesis. Here we investigated the effects of KRICT-9 on neuroinflammation and amyloidogenesis in in vitro and in vivo AD models. We found that KRICT-9 decreased lipopolysaccharide (LPS)-induced inflammation in microglial BV-2 cells and astrocytes while reducing nitric oxide generation and expression of inflammatory marker proteins (iNOS and COX-2) as well as APP, BACE1, C99, Iba-1, and GFAP. KRICT-9 also inhibited β-secretase. Pull-down assays and docking model analyses indicated that KRICT-9 binds to the DNA binding domain of signal transducer and activator of transcription 3 (STAT3). KRICT-9 also decreased β-secretase activity and Aβ levels in tissues from LPS-induced mice brains, and it reversed memory impairment in mice. These experiments demonstrated that KRICT-9 protects against LPS-induced neuroinflammation and amyloidogenesis by inhibiting STAT3 activity. This suggests KRICT-9 or KRICT-9-inspired reagents could be used as therapeutic agents to treat AD.

Novel synthetic (E)-2-methoxy-4-(3-(4-methoxyphenyl) prop-1-en-1-yl) phenol inhibits arthritis by targeting signal transducer and activator of transcription 3

Rheumatoid arthritis (RA) is a severely debilitating chronic autoimmune disease that leads to long-term joint damage. Signal transducer and activator of transcription 3 (STAT3)-targeted small molecules have shown promise as therapeutic drugs for treating RA. We previously identified (E)-2,4-bis(p-hydroxyphenyl)-2-butenal (BHPB), a tyrosine-fructose Maillard reaction product, as a small molecule with potent anti-inflammatory and anti-arthritic properties, mediated through the inhibition of STAT3 activation. The aim of this study was to develop a novel BHPH derivative with improved anti-arthritic properties and drug-likeness. We designed and synthesised (E)-2-methoxy-4-(3-(4-methoxyphenyl) prop-1-en-1-yl) phenol (MMPP), a novel synthetic BHPB analogue, and investigated its anti-inflammatory and anti-arthritic activities in experimentally-induced RA. We showed that MMPP strongly inhibited pro-inflammatory responses by inhibiting in vitro STAT3 activation and its downstream signalling in murine macrophages and human synoviocytes from patients with RA. Furthermore, we demonstrated that MMPP exhibited potent anti-arthritic activity in a collagen antibody-induced arthritis (CAIA) mouse model in vivo. Collectively, our results suggest that MMPP has great potential for use in the treatment of RA.

Expression of microRNA-34a in Alzheimer's disease brain targets genes linked to synaptic plasticity, energy metabolism, and resting state network activity

Polygenetic risk factors and reduced expression of many genes in late-onset Alzheimer's disease (AD) impedes identification of a target(s) for disease-modifying therapies. We identified a single microRNA, miR-34a that is over expressed in specific brain regions of AD patients as well as in the 3xTg-AD mouse model. Specifically, increased miR-34a expression in the temporal cortex region compared to age matched healthy control correlates with severity of AD pathology. miR-34a over expression in patient's tissue and forced expression in primary neuronal culture correlates with concurrent repression of its target genes involved in synaptic plasticity, oxidative phosphorylation and glycolysis. The repression of oxidative phosphorylation and glycolysis related proteins correlates with reduced ATP production and glycolytic capacity, respectively. We also found that miR-34a overexpressed neurons secrete miR-34a containing exosomes that are taken up by neighboring neurons. Furthermore, miR-34a targets dozens of genes whose expressions are known to be correlated with synchronous activity in resting state functional networks. Our analysis of human genomic sequences from the tentative promoter of miR-34a gene shows the presence of NFκB, STAT1, c-Fos, CREB and p53 response elements. Together, our results raise the possibilities that pathophysiology-induced activation of specific transcription factor may lead to increased expression of miR-34a gene and miR-34a mediated concurrent repression of its target genes in neural networks may result in dysfunction of synaptic plasticity, energy metabolism, and resting state network activity. Thus, our results provide insights into polygenetic AD mechanisms and disclose miR-34a as a potential therapeutic target for AD.

Z-guggulsterone negatively controls microglia-mediated neuroinflammation via blocking IκB-α-NF-κB signals

Induction of pro-inflammatory factors is one of the characteristics of microglial activation and can be regulated by numerous active agents extracted from plants. Suppression of pro-inflammatory factors is beneficial to alleviate neuroinflammation. Z-guggulsterone, a compound extracted from the gum resin of the tree commiphora mukul, exhibits numerous anti-inflammatory effects. However, the role and mechanism of Z-guggulsterone in pro-inflammatory responses in microglia remains unclear. This study addressed this issue in in vitro murine microglia and in vivo neuroinflammation models. Results showed that Z-guggulsterone reduced inducible nitric oxide (iNOS) protein expression as well as nitric oxide (NO), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) production in LPS-stimulated BV-2 cells. Z-guggulsterone also reduced the mRNA level of iNOS, TNF-α, and IL-6. Mechanistic studies revealed that Z-guggulsterone attenuated the LPS-induced degradation of inhibitor κ B-α (IκB-α) as well as the LPS-induced nuclear translocation of nuclear factor-κB (NF-κB). Z-guggulsterone, however, failed to reduce the LPS-induced increase in NF-κB phosphorylation level. These major findings were ascertained in primary microglia where the LPS-induced increases in iNOS expression, NO content, and IκB-α degradation were diminished by Z-guggulsterone treatment. In a mouse model of neuroinflammation, Z-guggulsterone exhibited significant anti-inflammatory effects, which were exemplified by the attenuation of microglial activation and neuroinflammation-induced behavioral abnormalities in Z-guggulsterone-treated mice. Taken together, these studies demonstrate that Z-guggulsterone attenuates the LPS-mediated induction of pro-inflammatory factors in microglia via inhibition of IκB-α-NF-κB signals, providing evidence to uncover the potential role of Z-guggulsterone in neuroinflammation-associated disorder therapies.

Perturbation of the transcriptome: implications of the innate immune system in Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disease with broad impact. Although Aβ and tau have been proposed as the key molecules in the disease mechanism, comprehensive understanding of AD pathogenesis requires a systemic view at the genomic level. From studies on the brain transcriptome of AD, we have gradually realized the contribution of the immune system to AD development. Recent explorations on the blood transcriptome of AD patients have revealed robust immune activation in the peripheral blood. The combination of transcriptome studies and other types of studies has further elucidated the roles of specific immune pathways in distinct cell types during AD development and highlighted the critical contributions from immune genes such as TREM2.

Anti-arthritis effects of (E)-2,4-bis(p-hydroxyphenyl)-2-butenal are mediated by inhibition of the STAT3 pathway

BACKGROUND AND PURPOSE

Products of Maillard reactions between aminoacids and reducing sugars are known to have anti-inflammatory properties. Here we have assessed the anti-arthritis effects of (E)-2,4-bis(p-hydroxyphenyl)-2-butenal and its possible mechanisms of action.

EXPERIMENTAL APPROACH

We used cultures of LPS-activated macrophages (RAW264.7 cells) and human synoviocytes from patients with rheumatoid arthritis for in vitro assays and the collagen-induced arthritis model in mice. NO generation, iNOS and COX2 expression, and NF-κB/IKK and STAT3 activities were measured in vitro and in joint tissues of arthritic mice, along with clinical scores and histopathological assessments. Binding of (E)-2,4-bis(p-hydroxyphenyl)-2-butenal to STAT3 was evaluated by a pull-down assay and its binding site was predicted using molecular docking studies with Autodock VINA.

KEY RESULTS

(E)-2,4-bis(p-hydroxyphenyl)-2-butenal (2.5-10 μg·mL(-1) ) inhibited LPS-inducedNO generation, iNOS and COX2 expression, and NF-κB/IKK and STAT3 activities in macrophage and human synoviocytes. This compound also suppressedcollagen-induced arthritic responses in mice by inhibiting expression of iNOS and COX2, and NF-κB/IKK and STAT3 activities; it also reduced bone destruction and fibrosis in joint tissues. A pull-down assay showed that (E)-2,4-bis(p-hydroxyphenyl)-2-butenal interfered with binding of ATP to STAT3. Docking studies suggested that (E)-2,4-bis(p-hydroxyphenyl)-2-butenal bound to the DNA-binding interface of STAT3 possibly inhibiting ATP binding to STAT3 in an allosteric manner.

CONCLUSIONS AND IMPLICATIONS

(E)-2,4-bis(p-hydroxyphenyl)-2-butenal exerted anti-inflammatory and anti-arthritic effects through inhibition of the NF-κB/STAT3 pathway by direct binding to STAT3. This compound could be a useful agent for the treatment of arthritic disease.

Neuroinflammatory and Amyloidogenic Activities of IL-32β in Alzheimer's Disease

Interleukin (IL)-32β can act as either pro-inflammatory or anti-inflammatory cytokines with being dependent on the status of disease development. Herein, we investigated whether IL-32β overexpression changes cytokine levels and affects amyloid-beta (Aβ)-induced pro-inflammation in the brain. IL-32β transgenic (Tg) mice and non-Tg mice were intracerebroventricularly infused with Aβ1-42 once a day for 14 days, and then cognitive function was assessed by the Morris water maze test and passive avoidance test. Our data showed that IL-32β Tg mice increased memory impairment, glia activation, amyloidogenesis, and neuroinflammation. The expression of glial fibrillary acid protein (GFAP), Iba1, and β-secretase 1 (BACE1) in the cortex and hippocampus was much higher in the Aβ1-42-infused IL-32β Tg mice brain. The activation of signal transducer and activator of transcription 3 (STAT3) and nuclear factor-kappa B (NF-κB) was much higher in Aβ1-42-infused IL-32β Tg mice brain. We also found that cytokines including IP-10, GM-CSF, JE, IL-13, and interferone-inducible T cell α chemoattractant (I-TAC) were elevated in Aβ1-42-infused IL-32β Tg mice brain. These results suggest that IL-32β could activate NF-κB and STAT3, and thus affect neuroinflammation as well as amyloidogenesis, leading to worsening memory impairment.

Gastrodin alleviates memory deficits and reduces neuropathology in a mouse model of Alzheimer's disease

Alzheimer's disease (AD) is a progressive, neurodegenerative disease, characterized by excessive accumulation of amyloid-beta (Aβ) and activation of microglia cells and astrocytes. In this research, we evaluated whether gastrodin, an active component isolated from the rhizome of Gastrodia elata, has neuroprotective effects in a mouse model of AD, Tg2576 mice. Treatment of gastrodin (60 mg/kg for 15 days) significantly improved memory impairments in the Morris water maze test and probe test. Moreover, immunohistochemical and ELISA results indicated that gastrodin significantly attenuated Aβ deposition and glial activation in brains of these transgenic mice. These findings suggested that gastrodin exerted neuroprotective activity via anti-inflammatory and anti-amyloidogenic effects and that gastrodin may be a potential option for AD therapy.

Anti-inflammatory effect of tricin 4'-O-(threo-β-guaiacylglyceryl) ether, a novel flavonolignan compound isolated from Njavara on in RAW264.7 cells and in ear mice edema

Although recent study has shown tricin 4'-O-(threo-β-guaiacylglyceryl) ether (TTGE), an isolated compound from Njavara rice, to have the most potent anti-inflammatory effects, the action mechanism has not been fully understood. Here, we examined the effect of TTGE on the inflammation and elucidated the potential mechanism. We demonstrated that TTGE significantly inhibited LPS-induced NO and ROS generation in RAW264.7 cells, which was correlated with the down-regulating effect of TTGE on the iNOS and COX-2 expression via NF-κB and STAT3. TPA-induced ear edema was also efficiently inhibited by the TTGE treatment. TTGE blocked the induction of iNOS and COX-2 through the regulation of NF-κB and STAT3, which could explain the reduced TPA-induced edema symptoms. Moreover, the introduction of ERK inhibitor abrogated the anti-inflammatory effect of TTGE via the recovery of NF-κB and STAT3 signalings. Taken together, these results suggest that TTGE has anti-inflammatory properties through down-regulation of NF-κB and STAT3 pathways.

Placenta-derived mesenchymal stem cells improve memory dysfunction in an Aβ1-42-infused mouse model of Alzheimer's disease

Mesenchymal stem cells (MSCs) promote functional recoveries in pathological experimental models of central nervous system (CNS) and are currently being tested in clinical trials for neurological disorders, but preventive mechanisms of placenta-derived MSCs (PD-MSCs) for Alzheimer's disease are poorly understood. Herein, we investigated the inhibitory effect of PD-MSCs on neuronal cell death and memory impairment in Aβ_1–42-infused mice. After intracerebroventrical (ICV) infusion of Aβ_1–42 for 14 days, the cognitive function was assessed by the Morris water maze test and passive avoidance test. Our results showed that the transplantation of PD-MSCs into Aβ_1–42-infused mice significantly improved cognitive impairment, and behavioral changes attenuated the expression of APP, BACE1, and Aβ, as well as the activity of β-secretase and γ-secretase. In addition, the activation of glia cells and the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were inhibited by the transplantation of PD-MSCs. Furthermore, we also found that PD-MSCs downregulated the release of inflammatory cytokines as well as prevented neuronal cell death and promoted neuronal cell differentiation from neuronal progenitor cells in Aβ_1–42-infused mice. These data indicate that PD-MSC mediates neuroprotection by regulating neuronal death, neurogenesis, glia cell activation in hippocampus, and altering cytokine expression, suggesting a close link between the therapeutic effects of MSCs and the damaged CNS in Alzheimer's disease.