Search Results (507)

Alzheimer’s disease (AD) is a prevalent chronic neurodegenerative disorder; the progression of this disease is driven by cellular determinants such as oxidative stress and dysregulated neurotrophic signaling. Lavender essential oil is traditionally used in aromatherapy for neuronal regulation and neuroprotection, suggesting its potential neuroprotective effects for chronic neurodegenerative disorders like AD. However, the key active constituents responsible for its benefits and the specific molecular pharmacological mechanisms remain unclear. In this study, we isolated myrtenol from lavender essential oil under the guidance of activity evaluation. Its neuroprotective effects were evaluated in PC12 cells via neurite outgrowth, anti-Aβ/H₂O₂ cytotoxicity, and antioxidant assays. Targets and pathways were explored using inhibitor experiments, cell thermal shift assay (CETSA), drug affinity responsive target stability (DARTS), and Western blot. Myrtenol significantly induced neurite outgrowth in PC12 cells and effectively mitigated cytotoxicity and oxidative stress damage induced by Aβ_25–35 and H₂O₂. Mechanistic studies revealed that myrtenol’s effects are associated with the modulation of tyrosine kinase receptor A (TrkA) and insulin-like growth factor-1 receptor (IGF-1R), activating phospholipase C (PLC)/protein kinase C (PKC) and phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathways to jointly mediate neuroprotection effects against the pathology of AD. This study demonstrates that myrtenol as a highly active component of lavender essential oil possesses NGF-like neuritogenic activity and neuroprotective effects. It provides a foundation for understanding the cellular mechanisms of myrtenol as a small-molecule lead for further investigation in neurodegeneration-related research. Full article

Keishikaryukotsuboreito (KKT) is a Kampo formula prescribed for neuropsychiatric symptoms, whereas Keishito (KT), despite including most of the constituent herbs, is not indicated for such conditions, suggesting distinct biological actions. We examined whether KT and KKT modulate nerve growth factor (NGF)-induced neurite outgrowth in PC12 cells. Cells were stimulated with NGF in the presence or absence of KT or KKT, and neurite extension was quantified. The involvement of NGF receptor signaling was assessed using the Trk inhibitor K-252a. KKT, but not KT, enhanced NGF-induced neurite outgrowth in a concentration-dependent manner without affecting basal morphology. Pharmacological analysis showed that KKT increased the maximal NGF-induced neurite response (E_max) without altering NGF potency (EC₅₀). K-252a completely abolished NGF-induced neurite extension and KKT-mediated enhancement, indicating that the effect was entirely dependent on NGF–TrkA signaling. These findings demonstrate that KKT selectively augments NGF-elicited neuronal differentiation and suggest translational relevance as a neurotrophic strategy. Full article

Background/Objectives: Blast-induced hearing loss (BIHL) is a major concern, particularly for military personnel, and is linked to impaired auditory neuron survival and synaptic plasticity. This study investigates the potential of the TrkB agonist 7,8-dihydroxyflavone (7,8-DHF) to reduce the severity of BIHL and promote recovery in a mouse model. Methods: Eight-week-old male C57BL/6J mice were used. A custom-built, compressed air-driven system utilizing a modified paintball apparatus was employed to deliver controlled unilateral double blasts (~22 psi exposure pressure) to the left ear. The blasts were administered 30 min apart. Immediately following the second blast, mice received either 7,8-DHF (10 mg/kg) or vehicle (10% DMSO) via intraperitoneal injection. Auditory brainstem responses (ABRs) were measured in both ears at baseline (pre-blast) and at several post-exposure time points. Results: The consecutive blast exposure induced a significant elevation in ABR thresholds, indicative of hearing loss, in both the ipsilateral (exposed) and contralateral (unexposed) ears of vehicle-treated mice. Notably, mice treated with 7,8-DHF demonstrated a marked improvement in hearing recovery compared to the vehicle group. Significant reductions in ABR thresholds were observed in the ipsilateral ear at 4 weeks post-blast (p < 0.0001) and in the contralateral ear as early as 1-week post-blast (p = 0.0236). However, the recovery was partial, with ABR thresholds plateauing after 4 weeks. Conclusions: A controlled blast model demonstrates that systemic administration of the TrkB agonist 7,8-DHF exerts a protective effect, partially restoring auditory function after blast injury. This supports the therapeutic potential of targeting the BDNF-TrkB signaling pathway for managing BIHL. Full article

Background/Objectives: Perfluorooctane sulfonic acid (PFOS), a persistent industrial chemical, has been associated with impairments in cognition. While several studies have attempted to identify the underlying mechanisms, the precise pathways mediating these cognitive deficits remain incompletely understood. PFOS induces cell death in basal forebrain cholinergic neurons (BFCNs), a population critically involved in maintaining cognitive function, partially through the disruption of thyroid hormone signaling. These neurotoxic effects could be mediated through multiple interconnected pathways, including the generation of oxidative stress, dysregulation of prostaglandin E2 (PGE2) signaling, and disruption of nerve growth factor (NGF) homeostasis, all of which have been independently linked to BFCN degeneration and cognitive dysfunction and reported to be induced after PFOS exposure. Methods: To systematically evaluate PFOS-induced neurodegeneration in BFCNs, we employed the SN56 cholinergic cell line derived from the basal forebrain. Cells were exposed to PFOS across a concentration range (0.1–40 μM) in combination with various pharmacological agents: triiodothyronine (T3; 15 nM), recombinant NGF (20 μM), MF-63 (1 μM), and N-acetylcysteine (1 mM). Results: Our experimental results show that PFOS exposure (both single 1-day and repeated 14-day treatments) triggers oxidative stress through reactive oxygen species accumulation coupled with diminished NRF2 pathway activity. Furthermore, PFOS disrupts both PGE2 signaling and the NGF/TrkA/P75^NTR neurotrophic pathways, ultimately leading to BFCN cell death. These neurotoxic effects appear to be partially mitigated through T3 treatment, among other mechanisms. Conclusions: These findings provide valuable mechanistic insights into PFOS-induced BFCN neurodegeneration and the consequent cognitive decline while simultaneously suggesting potential therapeutic strategies to counteract these detrimental effects. Full article

Background/Objectives: Stewartia pseudocamellia Maxim. (S. pseudocamellia) has been reported to possess antioxidant and anti-inflammatory properties and contains various bioactive flavonoids and phenolic compounds. These components may contribute to neuroprotective effects relevant to depression and cognitive dysfunction. This study was conducted to evaluate the effects of 20% ethanolic extract from S. pseudocamellia leaves (ESP) on chronic unpredictable mild stress (CUMS)-induced depressive-like behaviors and cognitive dysfunction in C57BL/6 mice. Methods: C57BL/6 mice were divided into six groups: normal control (NC), normal sample (NS; ESP 100 mg/kg), CUMS, L-theanine (Thea; 4 mg/kg), ESP 50 mg/kg, and ESP 100 mg/kg groups. Phytochemical profiling of ESP was performed using ultra-performance liquid chromatography–quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF-MS/MS). Depressive-like behaviors and cognitive function were assessed, along with stress-related hormonal regulation and associated cellular signaling pathways. Results: Phytochemical profiling of ESP identified procyanidin B2, epicatechin, rutin, catechin gallate, kaempferol 3-O-glucoside, and quercitrin as major constituents. ESP significantly alleviated CUMS-induced depressive-like behaviors and improved spatial learning and memory. These effects were associated with modulation of stress-related hormones in serum and hypothalamic–pituitary–adrenal (HPA) axis–related proteins in the brain. ESP also enhanced antioxidant defense by activating the Nrf2 signaling pathway and improving mitochondrial function. Furthermore, ESP attenuated neuroinflammation and apoptosis by regulating the TLR4/NF-κB and JNK pathways, and promoted neuroplasticity by modulating cholinergic activity, with enhanced BDNF/TrkB signaling in the cerebral cortex and hippocampus. Conclusions: Collectively, these findings suggest that ESP exerts protective effects against CUMS-induced depressive-like behaviors and cognitive deficits in a preclinical model. Full article

Advances in multimodal therapy for high-risk neuroblastomas (NBs) have plateaued, prompting therapeutic initiatives to harness the immune system. NBs, however, are immunologically “cold” and a significant challenge to immunotherapy. Here, in a Jurkat lymphocyte cytotoxicity model, we describe an antigen-independent, cell-mediated mechanism for eliminating NB cells, first detected in PMA-activated low pcDNA-SH-SY5Y and high TrkAIII-SH-SY5Y TrkAIII-expressing cells, which are resistant to Jurkat elimination under normal conditions. Characterization of this mechanism through live cell imaging, adhesion assays, RT-PCR, Western blotting and indirect IF, employing a variety of inhibitors, indicates that it initiates with PMA-induced NB cell CCL2 expression. This results in CCL2 promotion of Jurkat CCR2b expression, CCL2/CCR2b-mediated Jurkat LFA-1 activation and the formation of cytotoxic lipid-raft LFA1/ICAM-1 immune synapses, through which Jurkat m-TRAIL combines with PMA-enhanced NB cell DR5/TRAIL-R2 expression to induce NB cell apoptosis. This mechanism is enhanced by the NB-associated oncoprotein TrkAIII through Shp/Src-regulated c-FLIP sequester and is PD-L1/PD-1-independent and resistant to osteoprotegerin. It eliminates both non-MYCN-amplified (SH-SY5Y and SK-N-SH) and MYCN-amplified (SMS-KCNR) NB cells that exhibit PMA-inducible CCL2 expression but not MYCN-amplified NB cells (IMR-32 and NB-1) that exhibit CCL2 repression, and is offset by reciprocal NB cell-induced Fas-mediated Jurkat cell apoptosis. These findings form a solid foundation for further pre-clinical development aimed at identifying clinically relevant physiological immune cell equivalents and alternative PKC activators, with the ultimate goal of translating this mechanism into an effective immune-therapeutic approach for the treatment of high-risk non-immunogenic NBs, especially NBs that exhibit CCL2 and TrkAIII expression. Full article

Background/Objectives: Colorectal cancer (CRC) shows significant molecular diversity influenced by tumor location. Right- and left-sided CRCs differ in terms of microsatellite instability (MSI), mutational burden, and actionable biomarkers. This study aimed to characterize the clinicopathological and molecular features of CRC stratified upon tumor location. Methods: A consecutive series of CRC cases was retrospectively analyzed. Tissue samples were obtained from primary tumors (71%) or metastatic lesions (29%). All cases were evaluated by histopathology, immunohistochemistry (IHC), and targeted next-generation sequencing (NGS). Tumor location was assigned based on the primary tumor (43 right-sided and 35 left-sided cases). Results: Right-sided CRCs were more frequent in older patients and females and showed higher rates of deficient MMR (42% vs. 17%, p = 0.02), MSI-H (39% vs. 14%, p = 0.02), and high tumor mutational burden (TMB-high, ≥10 Mutations/Mb, 56% vs. 28%, p = 0.02). The most frequent pathogenic class 5 mutations were TP53 (65%), APC (49%), and KRAS (44%). APC was the most frequently mutated gene in both pathogenic (class 5) and likely pathogenic (class 4) categories, with class 5 variants more common in left-sided tumors and class 4 variants predominating in right-sided tumors. BRAF mutations showed a statistically significant trend toward higher frequency in right-sided tumors (p = 0.05). HER2/neu overexpression (3+) was seen in 15% of patients, exclusively in MSS left-sided tumors. PD-L1 expression (CPS ≥ 1) was detected in 20% of patients, irrespective of location, and pan-TRK IHC was negative in all cases. The 29% of samples derived from metastatic lesions were predominantly MSS/pMMR (87%). Conclusions: Tumor location in CRC correlates with distinct molecular patterns. Right-sided tumors are associated with dMMR, MSI-H, and higher TMB, while left-sided CRCs display more ERBB2 alterations and class 5 APC mutations. The results highlight the importance of integrating tumor location into personalized molecular diagnostics and therapeutic planning for CRC patients. Full article

Glaucoma is increasingly recognized as an ischemic neurodegenerative disorder that extends beyond elevated intraocular pressure (IOP) to involve complex vascular, metabolic, and inflammatory mechanisms. Retinal ganglion cells are particularly vulnerable to ischemia–reperfusion injury, oxidative stress, and chronic neuroinflammation, leading to progressive disconnection from central visual pathways. Current therapies primarily target IOP reduction but fail to address ischemia-driven neurodegeneration or to restore lost neuronal connectivity. Ischemia triggers excitotoxicity, oxidative stress, and a maladaptive inflammatory response involving activated microglia and astrocytes, perpetuating neuronal injury and suppressing intrinsic regenerative capacity. Thus, restoring neural plasticity and mitigating neuroinflammation represent key unmet therapeutic needs. Psychoplastogens are a class of compounds capable of rapidly enhancing structural and functional neuroplasticity and have recently emerged as promising multitarget agents. Compounds such as ketamine, psilocybin, N,N-dimethyltryptamine (DMT), and some newly synthesized non-hallucinogenic analogs act through convergent signaling pathways involving BDNF–TrkB–mTOR, promoting dendritic growth, synaptogenesis, and glial modulation. Beyond their neurotrophic effects, psychoplastogens seem to exert potent immunomodulatory actions. In this review we will explore the interplay between ischemia, neurodegeneration, neuroinflammation, and impaired plasticity in glaucoma, integrating mechanistic insights from cerebral ischemia. We discuss emerging preclinical evidence supporting psychoplastogens as neurorestorative and anti-inflammatory agents, propose their potential application in ocular ischemic neurodegeneration, and outline translational challenges for future studies. Full article

Hericium erinaceus (H. erinaceus), a medicinal mushroom, is a source of bioactive compounds with demonstrated neuroprotective potential. This activity is primarily attributed to two distinct classes of compounds: erinacines from the mycelium, which potently induce the synthesis of neurotrophins, protein growth factors essential for neuronal survival and health, and hericenones from the fruiting body, which subsequently appear to enhance or potentiate neurotrophin-activated signaling pathways. Preclinical evidence substantiates their ability to enhance neurotrophin levels, particularly Nerve Growth Factor (NGF) and Brain-Derived Neurotrophic Factor (BDNF), and activate their cognate Trk receptors. Activation of these pathways, including PI3K/AKT/mTOR and MAPK/ERK, converges on transcription factors such as CREB, promoting neuronal survival, neurite outgrowth, and synaptic plasticity. However, the precise molecular mechanisms linking these small molecules to the complex orchestration of neurotrophic gene expression remain incompletely defined. This review synthesizes current knowledge of the neurotrophic pharmacology of H. erinaceus bioactives and proposes a novel framework suggesting that non-coding RNAs (ncRNAs) play a key regulatory role. We hypothesize that hericenones and erinacines modulate key transcriptional hubs, such as CREB, Nrf2, and NF-κB, which in turn regulate the expression of specific ncRNAs (e.g., miR-132, miR-146a) known to control neurogenesis, synaptogenesis, oxidative stress, and neuroinflammation. This ncRNA-mediated mechanism may represent an un-explored axis that explains the pleiotropic neuroprotective effects of these compounds. We critically appraise the existing preclinical evidence, identify significant methodological limitations and translational gaps, and propose a structured research roadmap to test these ncRNA-centric hypotheses, aiming to accelerate the rational development of H. erinaceus-derived compounds for neurodegenerative diseases. Full article

Background: Neurotrophin receptor tyrosine kinase (NTRK) fusions are potent oncogenic mutations. Inhibitors such as larotrectinib, entrectinib and repotrectinib are used when cancer cells harbor NTRK1, NTRK2 or NTRK3 fusion. Signal disruption between nerve growth factor (NGF) and its target is thought to impact nociception. Withdrawal pain is reported with larotrectinib and entrectinib. Case presentation: Two male patients aged 37 and 41 years old and treated with, respectively, repotrectinib and larotrectinib for NTRK fusion-positive solid tumors experienced debilitating pain after abrupt cessation of their targeted therapy. Short courses of prednisone for the former and dexamethasone for the latter were initiated after failure of standard analgesia. Both patients improved within 24 h and the pain did not recur after steroids were weaned off. They had improvements in their functional status without unexpected toxicity. Conclusions and relevance: For patients experiencing TRK inhibitor withdrawal pain, especially when tapering down the inhibitor is not an available strategy, a short course of corticosteroids can provide lasting relief. These cases emphasize the importance of better understanding the mechanism underlying the relationship between NRTK, NGF and nociception. Full article

Hypoxia–ischemia (HI)-related brain injury impacts millions of neonates worldwide. Male neonates are two times more susceptible to developing HI. We have previously reported that the administration of the neurotrophin receptor tyrosine kinase B (TrkB) agonist 7,8-dihydroxyflavone (DHF) following neonatal HI increases hippocampal TrkB phosphorylation and improves hippocampal-dependent learning and memory in early adult life only in females. We hypothesize that sex differences in HI outcomes are due to alterations in neonatal hippocampal steroid content, mainly the neural testosterone. At postnatal day 9, C57BL/6J mice underwent sham and Vannucci’s HI surgeries and were treated either with DHF or vehicle control. Hippocampi and plasma were collected on days 1 and 3 post-HI and liquid chromatography tandem mass spectrometry was used to determine the testosterone (T), estradiol (E₂), progesterone (P₄), and corticosterone (CORT) contents in these samples. All hippocampal steroid contents were at least 10-fold higher than in plasma, suggesting neural synthesis. Males had higher hippocampal T content than females at 3 days post-HI. Treatment with DHF reduced T in the female hippocampi at 3 days post-HI, but not in males. These findings suggest that the neuroprotective effect of DHF in females may be mediated, at least in part, through the reduction in hippocampal T following HI. Full article

Background/Objectives: Ischemic stroke is a leading cause of death and disability, and neuroprotection therapies, or those that increase recovery, are not available. While the garlic-derived bioactive compound S-allyl cysteine (SAC) has shown neuroprotective properties, its subacute long-term effects remain underexplored, particularly in females. Methods: We evaluated whether SAC supports functional recovery after ischemia/reperfusion (IR), focusing on neurotrophin signaling, tropomyosin receptor kinase B (TrkB), protein kinase B (AKT), and extracellular signal-regulated kinase (ERK). Adult female Wistar rats underwent 1 h of ischemia and 15 days of reperfusion. SAC (100 mg/kg, i.p.) was administered at the onset of reperfusion and daily for 15 days. Motor and cognitive deficit tests were performed. Infarct area, Ki67, brain-derived neurotrophic factor (BDNF), vascular endothelial growth factor (VEGF), nerve growth factor (NGF), pTrkB, pAKT, and pERK levels were quantified in the cortex, striatum, and hippocampus. Results: MicroPET analysis revealed comparable glucose uptake between the IR and IR + SAC groups, indicating similar ischemic severity. SAC reduced infarct area (54.7%) and significantly improved motor deficits (53.9%), circling behavior (38.9%), and long-term memory compared with ischemia/reperfusion (IR) animals. SAC increased the proportion of Ki67-positive cells (4.3-fold in the cortex and 1.8-fold in the striatum) and enhanced neurotrophin levels, NGF (cortex), BDNF (cortex and striatum), VEGF (striatum), pTrkB, pAKT, and pERK (cortex and striatum). Conclusions: SAC supports post-ischemic recovery, improving motor performance and preserving long-term recognition memory, effects that could be associated with increased cell proliferation, neurotrophin levels, and activation of the TrkB, AKT, and ERK pathways. Full article

Major depressive disorder (MDD) is a leading cause of global morbidity and mortality. Although pharmacological treatments are widely used, their effects are often limited, and nearly half of patients show resistance to current antidepressants, including those unresponsive to all available therapies. These challenges highlight the need to better understand the neurobiological mechanisms driving MDD and to develop novel therapeutic strategies, especially those involving natural compounds with multitarget actions. Baicalin, a bioactive flavonoid from Scutellaria baicalensis, exhibits antioxidant, anti-inflammatory, and neuroprotective properties and has recently gained attention for its potential to improve cognitive deficits and mood disorders. In this study, we investigated baicalin’s antidepressant potential and its underlying mechanisms across multiple experimental levels. We found that oral administration of baicalin produced antidepressant-like effects in both naïve mice and those subjected to chronic restraint stress (CRS). CRS impaired hippocampal long-term potentiation (LTP), whereas baicalin restored these synaptic deficits. Importantly, intra-dorsal hippocampal microinjection of the TrkB receptor antagonist ANA-12 abolished baicalin’s antidepressant effects, indicating the involvement of BDNF–TrkB signaling. Baicalin also reduced reactive oxygen species (ROS)/H₂O₂ production in a BDNF-associated manner, demonstrating clear antioxidant activity. Molecular docking further suggested that baicalin binds more effectively to the TrkB receptor than ANA-12, supporting its capacity to activate TrkB-mediated signaling. By integrating in vivo, ex vivo, in vitro, and in silico approaches, our study shows that baicalin exerts robust antioxidant in vitro and antidepressant effects in vivo. These benefits are primarily mediated through activation of BDNF–TrkB signaling, leading to reduced ROS/H₂O₂ accumulation and alleviation of CRS-induced depression-like behaviors. Full article

Olive pomace (OP), a by-product of olive oil production, is a sustainable resource rich in bioactive compounds with potential applications in cosmetics and pharmaceuticals. This study investigates the protective effects of olive pomace juice (OPJ) against H₂O₂-induced neuronal damage and LPS-induced inflammatory responses in HT22 and BV2 cells, respectively. OPJ suppressed H₂O₂-induced cell death and exerted anti-apoptotic effects by reducing the BAX/BCL2 ratio and caspase-3 cleavage. OPJ also mitigated neurodegenerative hallmarks by decreasing amyloid fibrils formation and inhibiting β-secretase and acetylcholinesterase (AChE) activity. Mechanistically, OPJ enhanced antioxidant response by upregulating Nrf2 and its downstream molecule HO-1, along with increasing mRNA levels of antioxidant enzymes, including catalase, SOD1, and GPx. OPJ further activated AMPKα–SIRT1–PGC1α signaling and CREB–BDNF–TrkB signaling, suggesting modulation of key antioxidant, anti-apoptotic, and neurotrophic pathways. In BV2 cells, OPJ downregulated pro-inflammatory cytokines (IL-6 and IL-1β) and decreased iNOS and COX-2 expression through suppression of NF-κB and MAPK signaling pathways. HPLC analysis identified hydroxytyrosol (10.92%) as the major active compound in OPJ, which compared with tyrosol (2.18%), and hydroxytyrosol exhibited greater neuroprotective and anti-inflammatory effects than tyrosol. This study highlights the potential of OPJ and its major compound, hydroxytyrosol, as functional agents for mitigating neurodegeneration-related cellular response, supporting its application in the food and pharmaceutical industries. Full article

Brain-derived growth factor, BDNF, has critical roles in a wide variety of neuronal aspects, including cell survival, differentiation, and synaptic function after their maturation. TrkB, a high-affinity receptor for BDNF, is a major contributor in these neuronal aspects, and its functions are exerted via stimulating intracellular signaling pathways including the mitogen-activated protein kinase (MAPK) pathways. As a family of MAPKs, the functions of ERK1/2, p38MAPK, and JNKs have been extensively studied using in vivo and in vitro neuronal systems. ERK 1/2, a major serine-threonine kinase and belonging to the MAPK family, also works as a downstream molecule after activation of the BDNF/TrkB system. Interestingly, growing evidence has demonstrated that ERK1/2 signaling exerts a positive or negative influence on neurons in both healthy and pathological conditions in the central nervous system (CNS). Indeed, activation of ERK 1/2 stimulated by the BDNF/TrkB system is involved in the regulation of synaptic plasticity. On the other hand, overactivation of ERK1/2 signaling under pathological conditions is closely related to neurodegeneration. Furthermore, cell stress activates p38MAPKs and JNK signaling, contributing to the progression of neurodegeneration. In this review, we show how MAPK pathway signaling affects neuronal fate, including cell survival or cell death, in the CNS. Moreover, we discuss the involvement of overactivation of MAPK signaling in the neurodegeneration observed in Alzheimer’s disease (AD), Parkinson’s disease (PD), and Huntington’s disease (HD). Full article