Objective: To screen the key genes involved in gefitinib resistance of lung adenocarcinoma PC9/GR cells which harbored 19 exon mutation of epidermal growth factor receptor (EGFR) gene, and discuss the effect and mechanism of downregulation of solute carrier family 7 member 11 (SLC7A11) on the gefitinib resistance of PC9/GR cells. Methods: RNA microarray was conducted to detect the gene expressions in PC9 and PC9/GR cells. The differently expressed genes were screened by using limma package of R language and analyzed by Kyoto encyclopedia of genes and genomes (KEGG) pathway enrichment analysis. Western blotting was performed to determine the expression of SLC7A11 protein in PC9 and PC9/GR cells. PC9/GR cells were infected with lentivirus plasmid containing short hairpin RNA (shRNA) targeting SLC7A11 or negative control shRNA (sh-NC), respectively. Real-time quantitative polymerase chain reaction (RT-qPCR) was performed to evaluate the efficacy of shRNA on the expression of SLC7A11 mRNA. Cell counting kit-8 (CCK-8) assay was conducted to determine the suppressing effect of gefitinib on PC9/GR cells. Mito-Tracker Red CMXRos probe and malondialdehyde (MDA) assay kit were used to evaluate gefitinib-induced ferroptosis in PC9/GR cells. Immunohistochemistry (IHC) was conducted to detect the expression of SLC7A11 protein in the tumor tissues of advanced stage lung adenocarcinoma patients harboring 19 exon mutation of EGFR gene. Thirty-six advanced stage lung adenocarcinoma patients who received EGFR-tyrosihe kinase inhibitor(TKI) as first-line treatment in Fourth Hospital of Hebei Medical Unviersity were enrolled. Kaplan-Meier survival curve was drawn to analyze the correlation between SLC7A11 expression and progression-free survival (PFS) of the patients. Results: RNA array demonstrated that 2 888 genes were differently expressed between PC9 and PC9/GR cells. KEGG analysis showed that ferroptosis-related gene was one of the most enriched region of the differently expressed genes between PC9 and PC9/GR cells. These ferroptosis-related gene cohort contained 13 genes, among which SLC7A11 exhibited the most significant difference. Western blotting showed that the expression of SLC7A11 protein in PC9/GR cells was significantly higher than that in PC9 cells (0.76±0.03 vs. 0.19±0.02, P<0.001). The 50% inhibiting concentration (IC(50)) of gefitinib was 35.08 μmol/L and 64.01 μmol/L for sh-SLC7A11 and sh-NC group PC9/GR cells, respectively. PC9/GR cells in sh-SLC7A11 group exhibited significantly lower density of mitochondria fluorescence after gefitinib treatment, compared to the sh-NC group (213.77±26.50 vs. 47.88±4.55, P<0.001). In addition, PC9/GR cells in sh-SLC7A11 group exhibited significantly higher MDA after gefitinib treatment, compared to the sh-NC group [(15.43±1.60) μmol/mg vs. (82.18±7.77) μmol/mg, P<0.001]. The PFS of the patients with low expression of SLC7A11 (n=18) was significantly longer than the patients with high expression of SLC7A11 (n=18, 16.77 months vs. 9.14 months, P<0.001). Conclusion: Downregulation of SLC7A11 could increase the sensitivity of PC9/GR cells to gefitinib by promoting ferroptosis.
Humans ; Gefitinib/therapeutic use* ; Antineoplastic Agents/therapeutic use* ; Lung Neoplasms/pathology* ; Down-Regulation ; Quinazolines/therapeutic use* ; Drug Resistance, Neoplasm/genetics* ; ErbB Receptors/metabolism* ; Adenocarcinoma of Lung ; Protein Kinase Inhibitors/therapeutic use* ; RNA, Small Interfering/genetics* ; Cell Line, Tumor ; Amino Acid Transport System y+/metabolism*

Objective: To screen the key genes involved in gefitinib resistance of lung adenocarcinoma PC9/GR cells which harbored 19 exon mutation of epidermal growth factor receptor (EGFR) gene, and discuss the effect and mechanism of downregulation of solute carrier family 7 member 11 (SLC7A11) on the gefitinib resistance of PC9/GR cells. Methods: RNA microarray was conducted to detect the gene expressions in PC9 and PC9/GR cells. The differently expressed genes were screened by using limma package of R language and analyzed by Kyoto encyclopedia of genes and genomes (KEGG) pathway enrichment analysis. Western blotting was performed to determine the expression of SLC7A11 protein in PC9 and PC9/GR cells. PC9/GR cells were infected with lentivirus plasmid containing short hairpin RNA (shRNA) targeting SLC7A11 or negative control shRNA (sh-NC), respectively. Real-time quantitative polymerase chain reaction (RT-qPCR) was performed to evaluate the efficacy of shRNA on the expression of SLC7A11 mRNA. Cell counting kit-8 (CCK-8) assay was conducted to determine the suppressing effect of gefitinib on PC9/GR cells. Mito-Tracker Red CMXRos probe and malondialdehyde (MDA) assay kit were used to evaluate gefitinib-induced ferroptosis in PC9/GR cells. Immunohistochemistry (IHC) was conducted to detect the expression of SLC7A11 protein in the tumor tissues of advanced stage lung adenocarcinoma patients harboring 19 exon mutation of EGFR gene. Thirty-six advanced stage lung adenocarcinoma patients who received EGFR-tyrosihe kinase inhibitor(TKI) as first-line treatment in Fourth Hospital of Hebei Medical Unviersity were enrolled. Kaplan-Meier survival curve was drawn to analyze the correlation between SLC7A11 expression and progression-free survival (PFS) of the patients. Results: RNA array demonstrated that 2 888 genes were differently expressed between PC9 and PC9/GR cells. KEGG analysis showed that ferroptosis-related gene was one of the most enriched region of the differently expressed genes between PC9 and PC9/GR cells. These ferroptosis-related gene cohort contained 13 genes, among which SLC7A11 exhibited the most significant difference. Western blotting showed that the expression of SLC7A11 protein in PC9/GR cells was significantly higher than that in PC9 cells (0.76±0.03 vs. 0.19±0.02, P<0.001). The 50% inhibiting concentration (IC(50)) of gefitinib was 35.08 μmol/L and 64.01 μmol/L for sh-SLC7A11 and sh-NC group PC9/GR cells, respectively. PC9/GR cells in sh-SLC7A11 group exhibited significantly lower density of mitochondria fluorescence after gefitinib treatment, compared to the sh-NC group (213.77±26.50 vs. 47.88±4.55, P<0.001). In addition, PC9/GR cells in sh-SLC7A11 group exhibited significantly higher MDA after gefitinib treatment, compared to the sh-NC group [(15.43±1.60) μmol/mg vs. (82.18±7.77) μmol/mg, P<0.001]. The PFS of the patients with low expression of SLC7A11 (n=18) was significantly longer than the patients with high expression of SLC7A11 (n=18, 16.77 months vs. 9.14 months, P<0.001). Conclusion: Downregulation of SLC7A11 could increase the sensitivity of PC9/GR cells to gefitinib by promoting ferroptosis.
Humans ; Gefitinib/therapeutic use* ; Antineoplastic Agents/therapeutic use* ; Lung Neoplasms/pathology* ; Down-Regulation ; Quinazolines/therapeutic use* ; Drug Resistance, Neoplasm/genetics* ; ErbB Receptors/metabolism* ; Adenocarcinoma of Lung ; Protein Kinase Inhibitors/therapeutic use* ; RNA, Small Interfering/genetics* ; Cell Line, Tumor ; Amino Acid Transport System y+/metabolism*

A boy, aged 1 year and 6 months, was found to have persistent positive urine glucose at the age of 4 months, with polydipsia, polyuria, and growth retardation. Laboratory examinations suggested that the boy had low specific weight urine, anemia, hypokalemia, hyponatremia, hypomagnesemia, metabolic acidosis, glycosuria, acidaminuria, increased fractional excretion of potassium, and decreased tubular reabsorption of phosphate. X-ray examinations of the head, thorax, and right hand showed changes of renal rickets. The slit-lamp examination showed a large number of cystine crystals in the cornea. The genetic testing showed a suspected pathogenic homozygous mutation of the
Amino Acid Transport Systems, Neutral/genetics* ; Cornea ; Cystinosis/genetics* ; Humans ; Hypokalemia ; Infant ; Male ; Mutation ; Rare Diseases

The neuronal activity-dependent change in the manner in which light is absorbed or scattered in brain tissue is called the intrinsic optical signal (IOS), and provides label-free, minimally invasive, and high spatial (~100 µm) resolution imaging for visualizing neuronal activity patterns. IOS imaging in isolated brain slices measured at an infrared wavelength (>700 nm) has recently been attributed to the changes in light scattering and transmittance due to aquaporin-4 (AQP4)-dependent astrocytic swelling. The complexity of functional interactions between neurons and astrocytes, however, has prevented the elucidation of the series of molecular mechanisms leading to the generation of IOS. Here, we pharmacologically dissected the IOS in the acutely prepared brain slices of the stratum radiatum of the hippocampus, induced by 1 s/20 Hz electrical stimulation of Schaffer-collateral pathway with simultaneous measurement of the activity of the neuronal population by field potential recordings. We found that 55% of IOSs peak upon stimulation and originate from postsynaptic AMPA and NMDA receptors. The remaining originated from presynaptic action potentials and vesicle fusion. Mechanistically, the elevated extracellular glutamate and K⁺ during synaptic transmission were taken up by astrocytes via a glutamate transporter and quinine-sensitive K2P channel, followed by an influx of water via AQP-4. We also found that the decay of IOS is mediated by the DCPIB- and NPPB-sensitive anion channels in astrocytes. Altogether, our results demonstrate that the functional coupling between synaptic activity and astrocytic transient volume change during excitatory synaptic transmission is the major source of IOS.
Action Potentials ; alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid ; Amino Acid Transport System X-AG ; Astrocytes ; Brain ; Electric Stimulation ; Glutamic Acid ; Hippocampus ; Jupiter ; Neurons ; Receptors, N-Methyl-D-Aspartate ; Synaptic Transmission ; Water

Chronic immobilization stress (CIS) induces low levels of glutamate (Glu) and glutamine (Gln) and hypoactive glutamatergic signaling in the mouse prefrontal cortex (PFC), which is closely related to the Glu-Gln cycle. A Gln-supplemented diet ameliorates CIS-induced deleterious changes. Here, we investigated the effects of CIS and Gln supplementation on Glu-Gln cycle-related proteins to characterize the underlying mechanisms. Using the CIS-induced depression mouse model, we examined the expression of 11 proteins involved in the Glu-Gln cycle in the PFC. CIS decreased levels of glutamate transporter 1 (GLT1) and sodium-coupled neutral amino acid transporter (SNAT) 1, SANT2, SNAT3, and SNAT5. Gln supplementation did not affect the non-stressed group but significantly increased GLT1 and SNATs of the stressed group. By immunohistochemical analysis, we confirmed that SNAT1 and SNAT2 were decreased in neurons and GLT1, SNAT3, and SNAT5 were decreased in astrocytes in the medial PFC of the stressed group, but Gln-supplemented diet ameliorated these decrements. Collectively, these results suggest that CIS may cause depressive-like behaviors by decreasing Glu and Gln transportation in the PFC and that a Gln-supplemented diet could prevent the deleterious effects of CIS.
Amino Acid Transport System X-AG ; Amino Acid Transport Systems ; Animals ; Astrocytes ; Depression ; Depressive Disorder ; Diet ; Glutamic Acid ; Glutamine ; Immobilization ; Mice ; Neurons ; Prefrontal Cortex ; Transportation

Drosophila dEAAT2, a member of the excitatory amino-acid transporter (EAAT) family, has been described as mediating the high-affinity transport of taurine, which is a free amino-acid abundant in both insects and mammals. However, the role of taurine and its transporter in hearing is not clear. Here, we report that dEAAT2 is required for the larval startle response to sound stimuli. dEAAT2 was found to be enriched in the distal region of chordotonal neurons where sound transduction occurs. The Ca imaging and electrophysiological results showed that disrupted dEAAT2 expression significantly reduced the response of chordotonal neurons to sound. More importantly, expressing dEAAT2 in the chordotonal neurons rescued these mutant phenotypes. Taken together, these findings indicate a critical role for Drosophila dEAAT2 in sound transduction by chordotonal neurons.
Acoustic Stimulation ; Action Potentials ; genetics ; Animals ; Animals, Genetically Modified ; Auditory Pathways ; physiology ; Calcium ; metabolism ; Drosophila ; genetics ; Drosophila Proteins ; genetics ; metabolism ; Excitatory Amino Acid Transporter 2 ; genetics ; metabolism ; Hearing ; genetics ; Larva ; Luminescent Proteins ; genetics ; metabolism ; Mutation ; genetics ; Nervous System ; cytology ; Neurons ; metabolism

OBJECTIVETo investigate the effect of ASCT2 gene (glutamine transporter) knock-down by shRNA on biological behaviors of colorectal cancer cells.

METHODSshRNA was transfected into colorectal cancer cells Lovo and SW480 to knockdown ASCT2 mediated by Lipofectamine 2000. Reverse transcription-PCR and Western blot were used to examine the mRNA and protein expression of ASCT2. MTT and transwell assay were used to determine the proliferation and invasiveness of Lovo and SW480 cells. Radioactive-tracer was used to detect the uptake of glutamine.

RESULTSASCT2 mRNA and protein levels were significantly down-regulated by shRNA in Lovo and SW480 cells(P<0.01). MTT and transwell assays showed that ASCT2 knock-down could significantly inhibit the proliferation of Lovo and SW480 cells (A490) and decrease the number of invasive Lovo and SW480 cells from the membrane (both P<0.01). The number of membrane Lovo cells in shASCT group and control group was 46.3±5.9 and 197.7±9.1, respectively while the number of membrane SW480 cells in shASCT group and control group was 29.7±3.8 and 139.0±9.5, respectively. Radioactive-tracer showed that shASCT2 transfection could significantly reduce the uptake of glutamine, with an inhibition rate of 79.15% in Lovo and 67.22% in SW480 cells (both P<0.01).

CONCLUSIONSASCT2 plays an oncogenic role in colonic cancer, and its promotion mechanism may be associated with glutamine metabolism. ASCT2 may be a novel therapeutic target of colonic cancer.

Amino Acid Transport System ASC ; drug effects ; genetics ; physiology ; Cell Line, Tumor ; physiology ; Cell Proliferation ; genetics ; Colorectal Neoplasms ; genetics ; physiopathology ; Down-Regulation ; drug effects ; Gene Knockdown Techniques ; methods ; Glutamine ; drug effects ; genetics ; physiology ; Humans ; Minor Histocompatibility Antigens ; drug effects ; genetics ; physiology ; Neoplasm Invasiveness ; genetics ; physiopathology ; Oncogenes ; drug effects ; genetics ; RNA, Messenger ; physiology ; RNA, Small Interfering ; pharmacology ; Transfection

Spinocerebellar ataxias (SCAs) are autosomal dominant neurodegenerative disorders which disrupt the afferent and efferent pathways of the cerebellum that cause cerebellar ataxia. Spectrin beta non-erythrocytic 2 (SPTBN2) gene encodes the β-III spectrin protein with high expression in Purkinje cells that is involved in excitatory glutamate signaling through stabilization of the glutamate transporter, and its mutation is known to cause spinocerebellar ataxia type 5. Three years and 5 months old boy with delayed development showed leukodystrophy and cerebellar atrophy in brain magnetic resonance imaging (MRI). Diagnostic exome sequencing revealed that the patient has heterozygous mutation in SPTBN2 (p.Glu1251Gln) which is a causative genetic mutation for spinocerebellar ataxia type 5. With the patient's clinical findings, it seems reasonable to conclude that p.Glu1251Gln mutation of SPTBN2 gene caused spinocerebellar ataxia type 5 in this patient.
Amino Acid Transport System X-AG ; Atrophy ; Brain ; Cerebellar Ataxia ; Cerebellum ; Efferent Pathways ; Exome ; Glutamic Acid ; Humans ; Magnetic Resonance Imaging ; Male ; Neurodegenerative Diseases ; Purkinje Cells ; Spectrin ; Spinocerebellar Ataxias*

OBJECTIVE: Deficient brain-derived neurotrophic factor (BDNF) is one of the important mechanisms underlying the neuroplasticity abnormalities in schizophrenia. Aberration in BDNF signaling pathways directly or circuitously influences neurotransmitters like glutamate and gamma-aminobutyric acid (GABA). For the first time, this study attempts to construct and simulate the BDNF-neurotransmitter network in order to assess the effects of BDNF deficiency on glutamate and GABA. METHODS: Using CellDesigner, we modeled BDNF interactions with calcium influx via N-methyl-D-aspartate receptor (NMDAR)-Calmodulin activation; synthesis of GABA via cell cycle regulators protein kinase B, glycogen synthase kinase and β-catenin; transportation of glutamate and GABA. Steady state stability, perturbation time-course simulation and sensitivity analysis were performed in COPASI after assigning the kinetic functions, optimizing the unknown parameters using random search and genetic algorithm. RESULTS: Study observations suggest that increased glutamate in hippocampus, similar to that seen in schizophrenia, could potentially be contributed by indirect pathway originated from BDNF. Deficient BDNF could suppress Glutamate decarboxylase 67-mediated GABA synthesis. Further, deficient BDNF corresponded to impaired transport via vesicular glutamate transporter, thereby further increasing the intracellular glutamate in GABAergic and glutamatergic cells. BDNF also altered calcium dependent neuroplasticity via NMDAR modulation. Sensitivity analysis showed that Calmodulin, cAMP response element-binding protein (CREB) and CREB regulated transcription coactivator-1 played significant role in this network. CONCLUSION: The study presents in silico quantitative model of biochemical network constituting the key signaling molecules implicated in schizophrenia pathogenesis. It provides mechanistic insights into putative contribution of deficient BNDF towards alterations in neurotransmitters and neuroplasticity that are consistent with current understanding of the disorder.
Amino Acid Transport System X-AG ; Brain-Derived Neurotrophic Factor* ; Calcium ; Calmodulin ; Cell Cycle ; Computer Simulation* ; Cyclic AMP Response Element-Binding Protein ; gamma-Aminobutyric Acid* ; Glutamate Decarboxylase ; Glutamic Acid* ; Glycogen Synthase Kinases ; Hippocampus ; N-Methylaspartate ; Neuronal Plasticity ; Neurotransmitter Agents ; Proto-Oncogene Proteins c-akt ; Schizophrenia* ; Signal Transduction ; Transportation

The present study investigated the role of spinal glutamate recycling in the development of orofacial inflammatory pain or trigeminal neuropathic pain. Experiments were carried out on male Sprague-Dawley rats weighing between 230 and 280 g. Under anesthesia, a polyethylene tube was implanted in the atlanto-occipital membrane for intracisternal administration. IL-1β-induced inflammation was employed as an orofacial acute inflammatory pain model. IL-1β (10 ng) was injected subcutaneously into one vibrissal pad. We used the trigeminal neuropathic pain animal model produced by chronic constriction injury of the infraorbital nerve. DL-threo-β -benzyloxyaspartate (TBOA) or methionine sulfoximine (MSO) was administered intracisternally to block the spinal glutamate transporter and the glutamine synthetase activity in astroglia. Intracisternal administration of TBOA produced mechanical allodynia in naïve rats, but it significantly attenuated mechanical allodynia in rats with interleukin (IL)-1 β-induced inflammatory pain or trigeminal neuropathic pain. In contrast, intracisternal injection of MSO produced anti-allodynic effects in rats treated with IL-1β or with infraorbital nerve injury. Intracisternal administration of MSO did not produce mechanical allodynia in naive rats. These results suggest that blockade of glutamate recycling induced pro-nociception in naïve rats, but it paradoxically resulted in anti-nociception in rats experiencing inflammatory or neuropathic pain. Moreover, blockade of glutamate reuptake could represent a new therapeutic target for the treatment of chronic pain conditions.
Amino Acid Transport System X-AG ; Anesthesia ; Animals ; Astrocytes ; Chronic Pain ; Constriction ; Glutamate-Ammonia Ligase ; Glutamic Acid* ; Humans ; Hyperalgesia ; Inflammation ; Interleukins ; Male ; Membranes ; Methionine Sulfoximine ; Models, Animal ; Neuralgia* ; Polyethylene ; Rats* ; Rats, Sprague-Dawley ; Recycling*