Fusion variations of neurotrophic receptor tyrosine kinase (NTRK) are oncogenic drivers in various solid tumors such as breast cancer, salivary gland carcinoma, infant fibrosarcoma, etc. Gene rearrangements involving NTRK1/2/3 lead to constitutive activation of the tropomyosin receptor kinase (TRK) domain, and the expressed fusion proteins drive tumor growth and survival. NTRK fusions are estimated to occur at a frequency of approximately 0.1% to 1% in non-small cell lung cancer (NSCLC). Epidermal growth factor receptor (EGFR) mutations are prevalent in NSCLC, but the frequency of EGFR G719A mutation is relatively low (about 2%), and EGFR mutations are typically mutually exclusive with NTRK fusion variants. The study presented the first documented case of lung adenocarcinoma harboring both EGFR G719A mutation and LMNA-NTRK1 fusion. A review of the literature was conducted to elucidate the role of NTRK fusion mutations in NSCLC and their relationship with EGFR mutations, aiming to enhance the understanding of NTRK fusion mutations in NSCLC.
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Humans ; Adenocarcinoma/genetics* ; Adenocarcinoma of Lung ; ErbB Receptors/genetics* ; Lamin Type A/genetics* ; Lung Neoplasms/genetics* ; Mutation ; Oncogene Proteins, Fusion/genetics* ; Receptor, trkA/metabolism*

OBJECTIVES: The neurotoxicity of carbon monoxide (CO) to the central nervous system is a key pathogenesis of delayed encephalopathy after acute carbon monoxide poisoning (DEACMP). Our previous study found that retinoic acid (RA) can suppress the neurotoxic effects of CO. This study further explores, in vivo and in vitro, the molecular mechanisms by which RA alleviates CO-induced central nervous system damage. METHODS: A cytotoxic model was established using the mouse hippocampal neuronal cell line HT22 and primary oligodendrocytes exposed to CO, and a DEACMP animal model was established in adult Kunming mice. Cell viability and apoptosis of hippocampal neurons and oligodendrocytes were assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and Annexin V/propidium iodide (PI) double staining. The transcriptional and protein expression of each gene was detected using real-time fluorescence quantitative PCR (RT-qPCR) and Western blotting. Long noncoding RNA (lncRNA) SNHG15 and LINGO-1 were knocked down or overexpressed to observe changes in neurons and oligodendrocytes. In DEACMP mice, SNHG15 or LINGO-1 were knocked down to assess changes in central nervous tissue and downstream protein expression. RESULTS: RA at 10 and 20 μmol/L significantly reversed CO-induced apoptosis of hippocampal neurons and oligodendrocytes, downregulation of SNHG15 and LINGO-1, and upregulation of brain-derived neurotrophic factor (BDNF) and tyrosine kinase receptor B (TrkB) (all P<0.05). Overexpression of SNHG15 or LINGO-1 weakened the protective effect of RA against CO-induced cytotoxicity (all P<0.05). Knockdown of SNHG15 or LINGO-1 alleviated CO-induced apoptosis of hippocampal neurons and oligodendrocytes and upregulated BDNF and TrkB expression levels (all P<0.05). Experiments in DEACMP model mice showed that knockdown of SNHG15 or LINGO-1 mitigated central nervous system injury in DEACMP (all P<0.05). CONCLUSIONS RA alleviates CO-induced apoptosis of hippocampal neurons and oligodendrocytes, thereby reducing central nervous system injury and exerting neuroprotective effects. LncRNA SNHG15 and LINGO-1 are key molecules mediating RA-induced inhibition of neuronal apoptosis and are associated with the BDNF/TrkB pathway. These findings provide a theoretical framework for optimizing the clinical treatment of DEACMP and lay an experimental foundation for elucidating its molecular mechanisms.
Animals ; RNA, Long Noncoding/physiology* ; Brain-Derived Neurotrophic Factor/genetics* ; Carbon Monoxide Poisoning/complications* ; Mice ; Tretinoin/pharmacology* ; Nerve Tissue Proteins/metabolism* ; Membrane Proteins/metabolism* ; Apoptosis/drug effects* ; Hippocampus/cytology* ; Receptor, trkB/metabolism* ; Neurons/drug effects* ; Male ; Brain Diseases/etiology* ; Oligodendroglia/drug effects* ; Signal Transduction ; Cell Line

OBJECTIVES: To exple the mechanism of Qixiong Zuogui Granules (QXZG) for enhancing synaptic plasticity in aging rats. METHODS: Forty SD rats were randomized into control group, aging model group, donepezil treatment group, and QXZG treatment group (n=10). Except for the control rats, all the rats were subjected to daily intraperitoneal injection of D-galactose for 8 consecutive weeks to induce brain aging, and donepezil hydrochloride and QXZG suspension were administered by gavage during modeling. After the interventions, the rats were evaluated for general conditions, behavioral changes, oxidative stress indicators, hippocampal pathologies, and expressions of the brain-derived neurotrophic factor (BDNF)/tyrosine kinase receptor B (TrkB) pathway, p16, and synaptic plasticity-associated proteins. RESULTS: The rats in the model group exhibited obvious aging phenotypes such as yellowing of the teeth and hair, body weight loss, and impaired learning and memory abilities, with decreased serum SOD and GSH-Px activities and increased serum MDA level. The rat models also showed obvious pathological changes, reduced Nissl bodies, and elevated p16 protein expression in the hippocampal CA1 region, with significantly decreased expression levels of BDNF, TrkB, CREB and synaptic plasticity proteins SYN, GAP43, and PSD95. Treatment with QXZG alleviated the aging phenotypes in the rat models, improved their learning and memory abilities and pathological changes in the hippocampal CA1 region, reduced oxidative stress and p16 protein expression, and promoted the expressions of the BDNF/TrkB pathway proteins and synaptic plasticity proteins. CONCLUSIONS QXZG enhances synaptic plasticity and reduces oxidative stress in aging rats possibly by upregulating the BDNF/TrkB signaling pathway proteins, thereby delaying brain aging and improving learning and memory abilities of the rats.
Animals ; Brain-Derived Neurotrophic Factor/metabolism* ; Neuronal Plasticity/drug effects* ; Signal Transduction/drug effects* ; Rats, Sprague-Dawley ; Receptor, trkB/metabolism* ; Rats ; Aging ; Drugs, Chinese Herbal/pharmacology* ; Male ; Oxidative Stress ; Hippocampus/metabolism*

Depression (Dep) is one of the most common concomitant symptoms of Parkinson's disease (PD), but there is a lack of detailed pathologic evidence for the occurrence of PD-Dep. Currently, the management of symptoms from both conditions using conventional pharmacological interventions remains a formidable task. In this study, we found impaired activation of extracellular signal-related kinase (ERK), reduced levels of transcription and translation, and decreased expression of brain-derived neurotrophic factor (BDNF) in the medial prefrontal cortex (mPFC) of PD-Dep rats. We demonstrated that the abnormal phosphorylation of α-synuclein (pS129) induced tropomyosin-related kinase receptor type B (TrkB) retention at the neuronal cell membrane, leading to BDNF/TrkB signaling dysfunction. We chose SEW2871 as an ameliorator to upregulate ERK phosphorylation. The results showed that PD-Dep rats exhibited improvement in behavioral manifestations of PD and depression. In addition, a reduction in pS129 was accompanied by a restoration of the function of the BDNF/ERK signaling loop in the mPFC of PD-Dep rats.
Animals ; Brain-Derived Neurotrophic Factor/metabolism* ; alpha-Synuclein/metabolism* ; Male ; Prefrontal Cortex/drug effects* ; Rats, Sprague-Dawley ; Depression/metabolism* ; MAP Kinase Signaling System/drug effects* ; Rats ; Parkinson Disease/metabolism* ; Receptor, trkB/metabolism* ; Phosphorylation ; Disease Models, Animal ; Signal Transduction

Humans ; Clinical Relevance ; Receptor, trkA/genetics* ; Neoplasms ; Digestive System Neoplasms/genetics* ; Oncogene Proteins, Fusion/genetics* ; Gene Fusion

Humans ; Receptor, trkA/genetics* ; Neoplasms/genetics* ; Biomarkers, Tumor ; Gene Rearrangement ; Oncogene Proteins, Fusion/genetics*

Humans ; Nerve Tissue Proteins ; Epithelial-Mesenchymal Transition/genetics* ; Constriction, Pathologic ; Receptors, Immunologic ; Epithelial Cells/metabolism* ; Smad3 Protein/metabolism* ; Transforming Growth Factor beta1/metabolism*

The neurotrophin-tyrosine receptor kinase B (TrkB) signaling pathway plays an important role in regulating the balance of excitation and inhibition in the primary visual cortex (V1). Previous studies have revealed its mechanism of regulating the level of cortical excitability by increasing the efficiency of excitatory transmission, but it has not been elucidated how TrkB receptors regulate the balance of excitation and inhibition through the inhibitory system, which in turn affects visual cortex function. Therefore, the objective of this study was to investigate how the TrkB signaling pathway specifically regulates the most important inhibitory neuron-PV neurons affects the visual cortex function of mice. The expression of TrkB receptor on PV neurons in the V1 region was specifically reduced by the virus, the functional changes of inhibitory and excitatory neurons in the primary visual cortex were recorded by multi-channel electrophysiological in vivo. The orientation discrimination ability of mice was tested by behavioral experiments, and altered orientation discrimination ability of mice was tested by behavioral experiments. The results showed that reduced expression of TrkB receptors on PV inhibitory neurons in primary visual cortex significantly increased the response intensity of excitatory neurons, reduced the orientation discrimination ability of inhibitory and excitatory neurons, and increased the signal-to-noise ratio, but the orientation discrimination ability at the individual level in mice showed a decrease. These results suggest that the TrkB signaling pathway does not modulate the function of PV neurons solely by increasing excitatory transmission targeting PV neurons, and its effect on neuronal signal-to-noise ratio is not due to enhancement of the inhibitory system.
Mice ; Animals ; Receptor, trkB/metabolism* ; Neurons/metabolism* ; Signal Transduction

Objective: To investigate the clinicopathological, immunohistochemical and molecular genetic characteristics of gastric carcinoma with NTRK-rearrangement/amplification. Methods: The clinicopathological data of gastric carcinoma cases with NTRK-rearrangement/amplification diagnosed from January 2011 to September 2020 at the Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School, China, were collected. The clinicopathological, immunophenotypic and molecular pathological features were analyzed. The relevant literature was reviewed. Results: There were 4 cases of gastric carcinoma with NTRK-rearrangement/amplification. All 4 patients were male, aged 57-67 years (average, 63 years). Tumor sizes ranged from 3.5 to 5.2 cm (average, 4.8 cm). All tumors were in the antrum. All 4 patients underwent radical gastrectomy and were followed up after the surgery. Morphologically, all tumors showed histological features with enteroblastic-differentiated gastric carcinoma. Tumor cells showed predominantly tubular/papillary architecture, with conspicuous vesicular nuclei and pale staining or transparent cytoplasm. Immunohistochemistry showed pan-TRK expression in all cases, with various degrees of positivity in the cytoplasm. All cases were subject to NTRK1/2/3 detection using fluorescence in situ hybridization. There were NTRK translocations in 2 cases and NTRK amplifications in 2 cases. These cases were further verified by RNAseq next generation sequencing which confirmed that NTRK1 gene translocation (TPM3-NTRK1) and NTRK2 gene translocation (NTRK2-SMCHD1) occurred in two cases, respectively. Conclusions: NTRK mutation occurs less frequently in gastric cancer. In this study, the cases mainly occur in the antrum. The morphology has the characteristics of enteroblastic differentiation. The tumors have unique histological, immunophenotypic and molecular characteristics, which require much attention from pathologists to effectively guide clinicians to choose the best treatment.
Humans ; Male ; Female ; Receptor, trkA/genetics* ; Stomach Neoplasms/surgery* ; In Situ Hybridization, Fluorescence ; Biomarkers, Tumor/genetics* ; Translocation, Genetic ; Carcinoma ; Oncogene Proteins, Fusion/genetics* ; Chromosomal Proteins, Non-Histone/genetics*

The goal of this study was to investigate the regulatory effect of angiotensin converting enzyme 2 (ACE2) on cellular inflammation caused by avian infectious bronchitis virus (IBV) and the underlying mechanism of such effect. Vero and DF-1 cells were used as test target to be exposed to recombinant IBV virus (IBV-3ab-Luc). Four different groups were tested: the control group, the infection group[IBV-3ab-Luc, MOI (multiplicity of infection)=1], the ACE2 overexpression group[IBV-3ab Luc+pcDNA3.1(+)-ACE2], and the ACE2-depleted group (IBV-3ab-Luc+siRNA-ACE2). After the cells in the infection group started to show cytopathic indicators, the overall protein and RNA in cell of each group were extracted. real-time quantitative polymerase chain reaction (RT-qPCR) was used to determine the mRNA expression level of the IBV nucleoprotein (IBV-N), glycoprotein 130 (gp130) and cellular interleukin-6 (IL-6). Enzyme linked immunosorbent assay (ELISA) was used to determine the level of IL-6 in cell supernatant. Western blotting was performed to determine the level of ACE2 phosphorylation of janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3). We found that ACE2 was successfully overexpressed and depleted in both Vero and DF-1 cells. Secondly, cytopathic indicators were observed in infected Vero cells including rounding, detaching, clumping, and formation of syncytia. These indicators were alleviated in ACE2 overexpression group but exacerbated when ACE2 was depleted. Thirdly, in the infection group, capering with the control group, the expression level of IBV-N, gp130, IL-6 mRNA and increased significantly (P < 0.05), the IL-6 level was significant or extremely significant elevated in cell supernatant (P < 0.05 or P < 0.01); the expression of ACE2 decreased significantly (P < 0.05); protein phosphorylation level of JAK2 and STAT3 increased significantly (P < 0.05). Fourthly, comparing with the infected group, the level of IBV-N mRNA expression in the ACE2 overexpression group had no notable change (P > 0.05), but the expression of gp130 mRNA, IL-6 level and expression of mRNA were elevated (P < 0.05) and the protein phosphorylation level of JAK2 and STAT3 decreased significantly (P < 0.05). In the ACE2-depleted group, there was no notable change in IBV-N (P > 0.05), but the IL-6 level and expression of mRNA increased significantly (P < 0.05) and the phosphorylation level of JAK2 and STAT3 protein decreased slightly (P > 0.05). The results demonstrated for the first time that ACE2 did not affect the replication of IBV in DF-1 cell, but it did contribute to the prevention of the activation of the IL-6/JAK2/STAT3 signaling pathway, resulting in an alleviation of IBV-induced cellular inflammation in Vero and DF-1 cells.
Animals ; Chlorocebus aethiops ; Humans ; Interleukin-6/genetics* ; Janus Kinase 2/pharmacology* ; Infectious bronchitis virus/metabolism* ; STAT3 Transcription Factor/metabolism* ; Angiotensin-Converting Enzyme 2/pharmacology* ; Cytokine Receptor gp130/metabolism* ; Vero Cells ; Signal Transduction ; Inflammation ; RNA, Messenger