Search Results (160)

Huntington’s Disease (HD) is characterized by prominent degeneration of the principal neurons of the striatum and by progressive motor and cognitive deterioration. Striatal neurons degenerate in HD due to multiple cell-autonomous and non-autonomous factors. Impaired neurotrophin signaling by brain-derived neurotrophic factor (BDNF) and its cognate receptor Tropomyosin receptor kinase B (TrkB) is an important mechanism underlying neuronal loss in HD. Fingolimod, a clinically approved oral drug for Multiple Sclerosis, was originally developed based on its anti-inflammatory properties. Recent work suggests that fingolimod can also promote BDNF expression and enhance neurotrophic support in the brain. We hypothesized that fingolimod treatment initiated during the presymptomatic phase would increase striatal BDNF levels and protect against motor dysfunction in HD. In wild-type mice, fingolimod treatment increases striatal BDNF levels and enhances BDNF-TrkB signaling. However, chronic fingolimod therapy (0.1 mg/kg, i.p., twice per week, over 7 weeks) initiated at age 4 weeks in the R6/2 mouse model of HD failed to improve behavioral locomotor deficits and exacerbated limb clasping. Furthermore, fingolimod treatment in these presymptomatic R6/2 mice acutely decreased BDNF-TrkB signaling in the striatum in a dose-dependent manner. In contrast, acute administration of fingolimod in symptomatic 7-week-old R6/2 mice increased striatal BDNF-TrkB signaling in a dose-dependent manner, consistent with previous work suggesting that chronic fingolimod can improve motor behavior when given during the symptomatic phase. Thus, the effects of fingolimod striatal BDNF-TrkB signaling and motor behavior in HD are complex and vary with disease stage. Addressing this variability is critical for the design of neuroprotective drug trials in HD, including those utilizing sphingosine-1-phosphate receptor (S1P) modulators. Full article

Chronic stress disrupts neuroendocrine regulation, neurotransmitter balance, and neuronal redox homeostasis, thereby contributing to the development of anxiety-related neuropathology. Arecoline, the predominant alkaloid of Areca catechu L., displays diverse neuropharmacological properties, yet its role in stress-induced emotional dysfunction has not been fully elucidated. This study examined the anxiolytic-like and neuroprotective effects of arecoline in mice exposed to chronic unpredictable mild stress (CUMS). Arecoline administration markedly improved behavioral outcomes, reflected by increased central exploration in the open-field test, prolonged time in the light compartment, and enhanced open-arm activity in the elevated plus maze. These behavioral benefits were accompanied by normalization of serum corticosterone levels, restoration of hippocampal neurotransmitters, reinforcement of antioxidant enzyme activities, and attenuation of pro-inflammatory cytokines. At the molecular level, arecoline elevated brain-derived neurotrophic factor (BDNF), tropomyosin receptor kinase B (TrkB), cAMP response element-binding protein (CREB), N-methyl-D-aspartate receptor (NMDAR), and Ca²⁺/calmodulin-dependent protein kinase II (CaMKII), indicating enhanced synaptic plasticity, while concurrently diminishing oxidative and inflammatory stress. Collectively, the findings suggest that arecoline exerts multifaceted neuroprotective actions under chronic stress by coordinating neuroendocrine modulation, neurotransmitter homeostasis, antioxidant defenses, and synaptic plasticity. This study provides new mechanistic evidence supporting the potential relevance of arecoline as a functional neuroactive compound for managing stress-induced anxiety disorders. Full article

Alzheimer’s disease (AD) is a progressive neurodegenerative disease, characterized by the accumulation of amyloid beta (aβ) plaques and neurofibrillary tangles, along with progressive deterioration of cognitive function. AD is the most common form of dementia and affects over 55 million people worldwide. Current treatments for AD are symptomatic-based rather than curative, which calls for the development of new therapeutic strategies. Stem cell therapy has shown promising results for neurodegenerative diseases, including AD. Brain-derived neurotrophic factor (BDNF) and its receptor, tropomyosin receptor kinase B (TrkB), and their downstream signalling cascades play crucial role in modulating neuronal survival, development and synaptic plasticity, which are vital for cognitive functioning, and this pathway is dysregulated in AD. While the BDNF/TrkB signalling pathway dysregulation and stem cell therapy are each widely studied in AD, the interplay between those two remains underexplored. This review focuses on the mechanistic insights of the BDNF/TrkB signalling pathway in normal physiological condition and AD, along with the effects of stem cell therapy on the pathway and its downstream cascades. The findings highlight the therapeutic outcomes in increasing BDNF/TrkB levels and functions, restoring synaptic plasticity, modulating downstream substrates activities and improving cognitive functions. In addition, challenges, limitations and future directions of stem cell therapy are discussed, underscoring the therapeutic benefits of this therapy for AD by modulating the BDNF/TrkB signalling pathway. Full article

We report a rare case of pulmonary tumor thrombotic microangiopathy (PTTM) in a patient with metastatic neurotrophic tropomyosin receptor kinase (NTRK) fusion-positive transverse colon cancer who exhibited a marked radiologic and biochemical response to entrectinib. Despite significant tumor shrinkage, progressive dyspnea and hypoxemia developed approximately four weeks after therapy initiation. Chest CT revealed diffuse interstitial infiltrates, initially interpreted as drug-induced pneumonitis or infection. Entrectinib was discontinued, but respiratory failure progressed, and the patient died shortly thereafter. Autopsy revealed widespread pulmonary microangiopathy with fibrocellular intimal proliferation and tumor emboli in small pulmonary arteries, consistent with PTTM. Notably, no hematogenous metastases were identified; instead, tumor spread appeared to occur via an atypical lymphatic route through the thoracic duct. The tumor exhibited microsatellite stability and a modest mutation burden, suggesting that lymphatic dissemination and microvascular pathology may progress independently of these genomic features. This case underscores a critical dissociation between oncologic response and vascular complications, indicating that tropomyosin receptor kinase (TRK) inhibitor monotherapy may be insufficient to prevent PTTM. Comprehensive management may require concurrent strategies targeting the pulmonary microvasculature, including antiangiogenic therapy and modulation of cytokine and growth factor signaling. Full article

Background/Objectives: The neurotrophic tropomyosin receptor kinase (NTRK) genes NTRK1, NTRK2, and NTRK3 encode tyrosine kinase receptors, and their fusion genes are known as the oncogenic driver genes for cancer. This study aimed to compare the diagnostic ability of NTRK fusion among five types of multi-cancer genome profiling tests (multi-CGP tests) and determine a useful multi-CGP test for NTRK fusion, recorded in the Center for Cancer Genomics and Advanced Therapeutics (C-CAT) database in Japan. This study aimed to compare the diagnostic results for NTRK fusions among the five different CGP tests. Methods: A total of 88,688 tumor cases were enrolled in the C-CAT profiling database from 2019 to 2024. The detection frequency of NTRK fusion genes was compared to the results for five multi-CGP tests: NCC Oncopanel, FoundationOne CDx (F1), FoundationOne Liquid (F1L), GenMineTOP (GMT), and Guardant360. Results: NTRK fusion genes were detected in 175 (0.20%) of the 88,688 total cases. GMT, which is equipped with RNA sequencing function, frequently detected NTRK fusion genes (20 of 2926 cases; 0.68%) in comparison with the other four multi-CGP tests that do not have RNA sequencing analysis. GMT showed significantly (p < 0.05) higher diagnostic ability for NTRK fusions compared with the other four multi-CGP tests. Especially, NTRK2 fusion was significantly (p < 0.001) more highly determined by GMT than it was by the other four multi-CGP tests. The detection rates for FGFR1 and FGFR3 were significantly higher in GMT than in other multi-CGP tests. In contrast, the detection rates of the ALK and RET fusion genes were significantly higher in F1L. Conclusions: GMT, which is equipped with RNA sequencing analysis, might show a useful diagnostic ability for NTRK fusions, especially for NTRK2 fusion genes. Full article

Aggressive behavior is regulated by intricate neural circuits and molecular mechanisms, notably through the interaction of brain-derived neurotrophic factor (BDNF) with its receptor, tropomyosin receptor kinase B (TrkB), which influences neuroplasticity and related behavioral phenotypes. We investigate the role of the BDNF signaling pathway in fish aggression using juvenile black rockfish (Sebastes schlegelii), which exhibit distinct aggressive phenotypes. The TrkB agonist 7,8-dihydroxyflavone (7,8-DHF) was administered intraperitoneally at doses of 1.25, 2.5, and 5 mg/kg to assess its effects on the behavioral characteristics of high-aggression (H-agg) and low-aggression (L-agg) phenotypes. Our findings indicate the following: (1) The effects of 7,8-DHF are dose-dependent, with 2.5 mg/kg identified as the effective threshold dose for H-agg individuals; (2) in the H-agg group, this dose significantly reduced locomotor acceleration, angular velocity, and activity frequency, while prolonging the first movement latency; (3) in the L-agg group, only angular velocity was significantly decreased with the 2.5 mg/kg treatment, with no significant changes observed in other behavioral parameters. This study provides the first evidence for differential behavioral responses to 7,8-DHF in S. schlegelii, demonstrating dose-dependent aggression suppression in H-agg phenotypes and threshold-specific responses in L-agg phenotypes. These insights into the neuro-molecular basis of fish aggression can guide phenotype-specific management in aquaculture, potentially improving stress management, reducing injuries and mortality, and boosting productivity. Full article

Childhood neuroblastoma (NB) is a malignant tumour that is a member of a class of embryonic tumours that have their origins in sympathoadrenal progenitor cells. There are five stages in the clinical NB staging system: 1, 2A, 2B, 3, 4S, and 4. For those diagnosed with stage 4 neuroblastoma (NBS4), the treatment options are limited with a survival rate of between 40 and 50%. Since 1975, more than 15 targets have been identified in the search for a treatment for high-risk NBS4. This article is concerned with the search for a multi-target drug treatment for high-risk NBS4 and focuses on four possible treatment targets that research has identified as having a role in the development of NBS4 and includes the inhibitors Histone Deacetylase (HDAC), Bromodomain (BRD), Hedgehog (HH), and Tropomyosin Kinase (TRK). Computer-aided drug design and molecular modelling have greatly assisted drug discovery in medicinal chemistry. Computational methods such as molecular docking, homology modelling, molecular dynamics, and quantitative structure–activity relationships (QSAR) are frequently used as part of the process for finding new therapeutic drug targets. Relying on these techniques, the authors describe a medicinal chemistry strategy that successfully identified eight compounds (inhibitors) that were thought to be potential inhibitors for each of the four targets listed above. Results revealed that all four targets BRD, HDAC, HH and TRK receptors binding sites share similar amino acid sequencing that ranges from 80 to 100%, offering the possibility of further testing for multi-target drug use. Two additional targets were also tested as part of this work, Retinoic Acid (RA) and c-Src (Csk), which showed similarity (of the binding pocket) across their receptors of 80–100% but lower than 80% for the other four targets. The work for these two targets is the subject of a paper currently in progress. Full article

Nociceptors respond to noxious stimuli and transmit pain signals to the central nervous system. In the cornea, the nociceptors located in the most external layer provide a myriad of sensation modalities. Damage to these corneal nerve fibers can induce neuropathic pain. In response, corneal nerves become sensitized to previously non-noxious stimuli. Assessing corneal pain origin is a complex ophthalmic challenge due to variations in its causes and manifestations. Current FDA-approved therapies for corneal nociceptive pain, such as acetaminophen and NSAIDs, provide only broad-acting relief with unwanted side effects, highlighting the need for precision medicine for corneal nociceptive pain. A few targeted treatments, including perfluorohexyloctane (F6H8) eye drops and Optive Plus (TRPV1 antagonist), are FDA-approved, while others are in preclinical development. Treatments that target signaling pathways related to neurotrophic factors, such as nerve growth factors and ion channels, such as the transient receptor potential (TRP) family or tropomyosin receptor kinase A, may provide a potential combinatory therapeutic approach. This review describes the roles of nociceptors in corneal pain. In addition, it evaluates molecules within nociceptor signaling pathways for their potential to serve as targets for efficient therapeutic strategies for corneal nociceptive pain aimed at modulating neurotrophic factors and nociceptive channel sensitivity. Full article

Thiol-containing drugs may interact with a region of tropomyosin receptor kinase A (TrkA), potentially inhibiting its activation by nerve growth factor (NGF). This action has been linked to potential analgesic activities. Here, we describe the ability of erdosteine, a thiolic compound classified as a mucolytic agent, to bind to the TrkA receptor sequence in silico and its in vitro effects on TrkA activation induced by NGF in cultured human neuroblastoma cells. Our results show that erdosteine and its metabolite, Met-1, bind to the TrkA receptor pocket, involving the primary TrkA residues Glu331, Arg347, His298, and His297. Furthermore, Met-1 has the ability to reduce the disulfide bridge between Cys300 and Cys345 of TrkA. In vitro measurement of TrkA autophosphorylation following NGF activation confirmed that erdosteine and Met-1 interfere with NGF-induced TrkA activation, leading to a consequent loss of the molecular recognition and spatial reorganization necessary for the induction of the autophosphorylation process. This effect was inhibited by low millimolar concentrations of the two compounds, reaching a maximal inhibition (around 40%) after 24 h of exposure to 1 mM erdosteine, and then plateauing. These findings suggest that erdosteine can act as a TrkA antagonist, thus indicating that this drug may have potential as an analgesic via a novel non-opioid mechanism of action operating through NGF signaling inhibition at the level of TrkA. Full article

Brain-derived neurotrophic factor (BDNF) is an important neuromodulator of nervous system functions and plays a key role in neuronal growth and survival, neurotransmission, and synaptic plasticity. The effects of BDNF are mainly mediated by the activation of tropomyosin receptor kinase B (TrkB), expressed in both the peripheral and central nervous system. BDNF has been implicated in several neuropsychiatric conditions such as schizophrenia and anxio-depressive disorders, as well as in pain states. This review summarizes the evidence for a critical role of BDNF throughout the pain system and describes contrasting findings of its pro- and anti-nociceptive effects. Different cellular sources of BDNF, its influence on neuroimmune signaling in pain conditions, and its effects in different cell types and regions are described. These and endogenous BDNF levels, downstream signaling mechanisms, route of administration, and approaches to manipulate BDNF functions could explain the bidirectional effects in pain plasticity and pain modulation. Finally, current knowledge gaps concerning BDNF signaling in pain are discussed, including sex- and pathway-specific differences. Full article

Background and Objectives: Neurotrophic receptor tyrosine kinase 3 (NTRK3) is a member of the tropomyosin receptor kinase family of receptor tyrosine kinases, which play a crucial role in neural development. However, owing to the limited number of studies about NTRK3 and cancer, we aimed to investigate NTRK3 as a potential prognostic marker for breast cancer (BC). Materials and Methods: We conducted a comprehensive analysis of NTRK3 expression in BC using the Tumor Immune Estimation Resource, Gene Expression Profiling Interactive Analysis 2, and Kaplan–Meier Plotter databases. We also explored the association between NTRK3 expression and tumor-infiltrating immune cells. Results: Low NTRK3 expression showed poorer prognosis in BC, as well as with T stage, pathology, and the Luminal subtype. In BC (BRCA), NTRK3 was positively correlated with CD4+ T cell, CD8+ T cell, macrophage, and neutrophil infiltration. Conclusions: These results suggest that NTRK3 may serve as a prognostic biomarker and provide novel insights into tumor immunology in BC. Therefore, NTRK3 represents a potential diagnostic and therapeutic target for BC treatment. Full article

The molecular regulation and therapeutic applications of brain-derived neurotrophic factor (BDNF)–tropomyosin-related kinase B (TrkB) signaling in major depressive disorder (MDD) through interaction with vascular endothelial growth factor (VEGF) and N-methyl-D-aspartic acid (NMDA) receptors show promise. While BDNF-TrkB signaling is implicated in antidepressant action, the association between BDNFs and depression has not yielded conclusive results. Some studies show decreased BDNF levels in depression, while others indicate that increased BDNF expression in certain brain regions can induce depression susceptibility. The role of BDNFs varies across different brain regions, necessitating further study of individual mechanisms. This regional variability complicates the development of targeted therapies. The antidepressant-like and neurotrophic actions of BDNFs require VEGF signaling, but there is also a reciprocal interdependence, as VEGF actions are dependent on BDNFs. This complex relationship complicates the development of targeted therapies. Full article

Background: Soft tissue sarcomas (STS) are aggressive cancers that show increasing response to novel targeted-therapies and immune-checkpoint-inhibitors. Despite anecdotal reports of cardiovascular adverse events (AEs) and major adverse cardiovascular events (MACE) potentially hindering their utility, the true cardiotoxic profile of these novel-therapies in STS has been largely understudied. Methods: We assessed the incidence and severity of AEs and MACE of contemporary FDA-approved targeted and immune-based therapies for STS, using data from landmark clinical trials supporting FDA-approval. We also analyzed data from the FDA adverse-event-reporting-system-(FAERS) for FDA-approved STS targeted and immune-based therapies for comparative real-world validation. Results: Overall, 12 clinical trials supporting FDA-approval of STS targeted-therapies and immune-checkpoint-inhibitors, incorporating 1249 patients, were identified. These clinical trials revealed 751 AEs including, hypertension (382, 50.87%), atrial fibrillation (3, 0.40%), myocardial infarction (2, 0.27%), cardiac failure (congestive included) (9, 1.20%), and cardiac failure (heart failure included) (7, 0.93%). Compared to placebo, those treated saw higher MACE (OR: 3.27, p < 0.001). The FAERS data showed 489 reported AEs including hypertension (275, 56.24%), atrial fibrillation (31, 6.34%), myocardial infarction (15, 3.07%), and cardiac failure (congestive included) (30, 6.13%). Programmed death-ligand 1 (PD-L1) inhibitors had the highest probability of AEs (0.65, 1.17), followed by tyrosine kinase inhibitors (0.66, 0.11), tropomyosin receptor kinase inhibitors (0.25, 0.13), mammalian target of rapamycin inhibitors (0.21, 0.09), and enhancer of zeste homologue 2 inhibitors (0.11, 0.06). Proportions were calculated from the samples in clinical trials supporting FDA-approval and FAERS, respectively. Conclusions: In this investigation, contemporary FDA-approved therapies for STS are associated with increased risk of AEs Full article

Background: Ouabain is a steroid hormone that binds to the sodium pump (Na⁺, K⁺-ATPase) at physiological (nanomolar) concentrations, activating different signaling pathways. This interaction has been shown to prevent the axotomy-induced death of retinal ganglion cells (RGCs), although the underlying mechanisms remain unclear. Objective: In this study, we investigated potential mechanisms by which ouabain promotes RGC survival using primary cultures of rat neural retina. Results: Our findings indicate that ouabain regulates brain-derived neurotrophic factor (BDNF) signaling in retinal cells via matrix metalloproteinase-9-mediated processing of proBDNF to mature BDNF (mBDNF) and by increasing the phosphorylation of the mBDNF receptor, tropomyosin-related receptor kinase B. Ouabain also enhances the maturation of interleukin (IL)-1β through the increased activation of caspase-1, which mediates the processing of proIL-1β into IL-1β, and transiently upregulates both IL-1 receptor and IL-1 receptor antagonist (IL-1Ra). Treatment using either IL-1β or IL-1Ra alone is sufficient to enhance RGC survival similarly to that achieved with ouabain. Finally, we further show that ouabain prevents RGC death through a complex signaling mechanism shared by BDNF and IL-1β, which includes the activation of the Src and protein kinase C pathways. Conclusions: Collectively, these results suggest that ouabain stimulates the maturation and signaling of both BDNF and IL-1β, which act as key mediators of RGC survival. Full article

Dexmedetomidine (DEX) is a selective alpha-2 adrenergic receptor agonist with sedative and anxiolytic properties. Increasing evidence reports that DEX has a neuroprotective effect. In this study, we investigated the potential effects of DEX on learning and memory functions in rats with experimental cognitive impairment. In the study, 21 adult male rats were used. The rats were divided into three groups, namely control, Scopolamine (SCOP) and SCOP + DEX. Cognitive impairment was induced with 1 mg/kg SCOP daily for 21 days. DEX was administered at a dose of 10 µg/kg between days 14 and 21 of the experiment. Following the injections, a spatial memory test was performed with a Morris Water Maze (MWM). At the end of the experiment, the hippocampus was dissected. The brain-derived neurotrophic factor (BDNF), acetylcholine (ACh) and acetylcholinesterase (AChE) levels were determined by ELISA. The tropomyosin receptor kinase B (TrkB) and Cyclic AMP-Response Element-Binding Protein (CREB) levels were measured by immunohistochemistry. DEX treatment improved the learning performance of rats compared to SCOP for 5 days. However, it did not significantly change memory performance. DEX increased the BDNF and ACh levels in the hippocampus while decreasing the AChE levels. Similarly, DEX treatment significantly increased CREB phosphorylation. No significant difference was observed between the TrkB receptor levels of the groups. This study demonstrated that the role of DEX in reducing SCOP-induced cognitive impairment is partially mediated by the increase in BDNF/TrkB/CREB signaling pathway activity. Full article