ABSTRACT
PURPOSE: Bioelectronic retinal prostheses that stimulate the remaining inner retinal neurons, bypassing degenerated photoreceptors, have been demonstrated to restore some vision in patients blinded by retinitis pigmentosa (RP). These implants encode luminance of the visual scene into electrical stimulation, however, leaving out chromatic information. Yet color plays an important role in visual processing when it comes to recognizing objects and orienting to the environment, especially at low spatial resolution as generated by current retinal prostheses. In this study, we tested the feasibility of partially restoring color perception in blind RP patients, with the aim to provide chromatic information as an extra visual cue. DESIGN: Case series. PARTICIPANTS: Seven subjects blinded by advanced RP and monocularly fitted with an epiretinal prosthesis. METHODS: Frequency-modulated electrical stimulation of retina was tested. Phosphene brightness was controlled by amplitude tuning, and color perception was acquired using the Red, Yellow, Green, and Blue (RYGB) hue and saturation scaling model. MAIN OUTCOME MEASURES: Brightness and color of the electrically elicited visual perception reported by the subjects. RESULTS: Within the tested parameter space, 5 of 7 subjects perceived chromatic colors along or nearby the blue-yellow axis in color space. Aggregate data obtained from 20 electrodes of the 5 subjects show that an increase of the stimulation frequency from 6 to 120 Hz shifted color perception toward blue/purple despite a significant inter-subject variation in the transition frequency. The correlation between frequency and blue-yellow perception exhibited a good level of consistency over time and spatially matched multi-color perception was possible with simultaneous stimulation of paired electrodes. No obvious correlation was found between blue sensations and array placement or status of visual impairment. CONCLUSIONS: These findings present a strategy for the generation and control of color perception along the blue-yellow axis in blind patients with RP by electrically stimulating the retina. It could transform the current prosthetic vision landscape by leading in a new direction beyond the efforts to improve the visual acuity. This study also offers new insights into the response of our visual system to electrical stimuli in the photoreceptor-less retina that warrant further mechanistic investigation.
Subject(s)
Blindness/physiopathology , Color Perception/physiology , Electric Stimulation Therapy , Retina/physiopathology , Retinitis Pigmentosa/therapy , Visual Prosthesis , Aged , Color Vision/physiology , Electrodes, Implanted , Female , Humans , Male , Middle Aged , Phosphenes , Photoreceptor Cells, Vertebrate/physiology , Retinitis Pigmentosa/physiopathology , Sensory Thresholds/physiology , Visual AcuityABSTRACT
Currently, blindness cannot be cured and patients' living quality can be compromised severely. Ultrasonic (US) neuromodulation is a promising technology for the development of noninvasive cortical visual prosthesis. We investigated the feasibility of transcranial focused ultrasound (tFUS) for noninvasive stimulation of the visual cortex (VC) to develop improved visual prosthesis. tFUS was used to successfully evoke neural activities in the VC of both normal and retinal degenerate (RD) blind rats. Our results showed that blind rats showed more robust responses to ultrasound stimulation when compared with normal rats. ( , two-sample t-test). Three different types of ultrasound waveforms were used in the three experimental groups. Different types of cortical activities were observed when different US waveforms were used. In all rats, when stimulated with continuous ultrasound waves, only short-duration responses were observed at "US on and off" time points. In comparison, pulsed waves (PWs) evoked longer low-frequency responses. Testing different parameters of PWs showed that a pulse repetition frequency higher than 100 Hz is required to obtain the low-frequency responses. Based on the observed cortical activities, we inferred that acoustic radiation force (ARF) is the predominant physical mechanism of ultrasound neuromodulation.
Subject(s)
Visual Cortex , Animals , Humans , Rats , Ultrasonic Waves , Ultrasonography , Visual Cortex/diagnostic imagingABSTRACT
While best known for its role in the innate immune system, the TANK-binding kinase 1 (TBK1) is now known to play a role in modulating cellular growth and autophagy. One of the major ways that TBK1 accomplishes this task is by modulating the mechanistic Target of Rapamycin (mTOR), a master regulator that when activated promotes cell growth and inhibits autophagy. However, whether TBK1 promotes or inhibits mTOR activity is highly cell type and context dependent. To further understand the mechanism whereby TBK1 regulates mTOR, we tested the hypothesis that TBK1 phosphorylates a key component of the mTOR complex 1 (mTORC1), Raptor. Using kinase assays coupled with mass spectrometry, we mapped the position of the TBK1 dependent phosphorylation sites on Raptor in vitro. Among the sites identified in vitro, we found that TBK1 promotes Raptor Ser877 phosphorylation in cells both basally and in response to pathogen-associated molecules known to induce TBK1 activity. The levels of Raptor Ser877 phosphorylation were inversely correlated with the levels of mTOR activity. Expression of a mutant Raptor that could not be phosphorylated at Ser877 led to an increase in mTORC1 activity. We conclude that TBK1 limits mTORC1 activity by promoting Raptor Ser877 phosphorylation.
Subject(s)
Mechanistic Target of Rapamycin Complex 1/metabolism , Protein Serine-Threonine Kinases/metabolism , Regulatory-Associated Protein of mTOR/metabolism , Serine/metabolism , Amino Acid Sequence , Cell Line , Enzyme Activation , Humans , Immunity, Innate , Mass Spectrometry , Mechanistic Target of Rapamycin Complex 1/chemistry , Models, Molecular , Phosphorylation , Protein Binding , Protein Serine-Threonine Kinases/chemistry , Regulatory-Associated Protein of mTOR/chemistry , Signal Transduction , Structure-Activity RelationshipABSTRACT
YAP signaling pathway plays critical roles in tissue homeostasis, and aberrant activation of YAP signaling has been implicated in cancers. To identify tractable targets of YAP pathway, we have performed a pathway-based pooled CRISPR screen and identified tankyrase and its associated E3 ligase RNF146 as positive regulators of YAP signaling. Genetic ablation or pharmacological inhibition of tankyrase prominently suppresses YAP activity and YAP target gene expression. Using a proteomic approach, we have identified angiomotin family proteins, which are known negative regulators of YAP signaling, as novel tankyrase substrates. Inhibition of tankyrase or depletion of RNF146 stabilizes angiomotins. Angiomotins physically interact with tankyrase through a highly conserved motif at their N terminus, and mutation of this motif leads to their stabilization. Tankyrase inhibitor-induced stabilization of angiomotins reduces YAP nuclear translocation and decreases downstream YAP signaling. We have further shown that knock-out of YAP sensitizes non-small cell lung cancer to EGFR inhibitor Erlotinib. Tankyrase inhibitor, but not porcupine inhibitor, which blocks Wnt secretion, enhances growth inhibitory activity of Erlotinib. This activity is mediated by YAP inhibition and not Wnt/ß-catenin inhibition. Our data suggest that tankyrase inhibition could serve as a novel strategy to suppress YAP signaling for combinatorial targeted therapy.
Subject(s)
Adaptor Proteins, Signal Transducing/antagonists & inhibitors , Carcinoma, Non-Small-Cell Lung/drug therapy , Carcinoma, Non-Small-Cell Lung/metabolism , ErbB Receptors/antagonists & inhibitors , Intercellular Signaling Peptides and Proteins/metabolism , Lung Neoplasms/drug therapy , Lung Neoplasms/metabolism , Membrane Proteins/metabolism , Phosphoproteins/antagonists & inhibitors , Tankyrases/antagonists & inhibitors , Adaptor Proteins, Signal Transducing/genetics , Adaptor Proteins, Signal Transducing/metabolism , Angiomotins , Antineoplastic Agents/pharmacology , CRISPR-Cas Systems , Cell Line, Tumor , Down-Regulation , Erlotinib Hydrochloride/pharmacology , Gene Knockout Techniques , HEK293 Cells , Humans , Intercellular Signaling Peptides and Proteins/chemistry , Intercellular Signaling Peptides and Proteins/genetics , Membrane Proteins/chemistry , Membrane Proteins/genetics , Microfilament Proteins , Phosphoproteins/genetics , Phosphoproteins/metabolism , Protein Interaction Domains and Motifs , Protein Stability/drug effects , RNA, Small Interfering/genetics , Signal Transduction/drug effects , Tankyrases/chemistry , Tankyrases/genetics , Transcription Factors , Ubiquitin-Protein Ligases/metabolism , YAP-Signaling ProteinsABSTRACT
Se realizó un estudio prospectivo, descriptivo para determinar que la pancreatitis inducida por la colangiopancreatografía retrógrada endoscópica (CPRE) puede ser usada como un modelo humano para el estudio de indicadores de inflamación liberados durante las primeras horas post trauma. Se practicó CPRE a 41 pacientes que acudieron al servicio de gastroenterología del HCU-AMP en el período febrero-diciembre de 1999, con clínica y paraclínica de síndrome ictérico obstructivo de etiología benigna. Se les practicó determinación de proteína C reactiva, amilasas e interleuquina 6 antes de iniciar y a las 24h posterior al mismo. Los pacientes admitidos en el estudio, 30 correspondían al sexo femenino (73,17 por ciento), 11 al sexo masculino (26,83 por ciento) con los diagnósticos de síndrome ictérico obstructivo, litiasis vesicular y/o coledociana, dilatación de vías biliares y divertículos yuxtapapilares. La edad promedio fue de 44-24 años. Se dividió a los pacientes en tres grupos de acuerdo a la evolución posterior al estudio: Grupo A: conformado por 4 pacientes que presentaron pancreatitis aguda leve según los criterios para pacientes sometidos a ERCP y elevación significativa de interleuquina 6 (IL-6) con respecto al Grupo C. Grupo B: integrado por 5 pacientes que presentaron dolor post canulación de las vías biliares sin hiperamilasemia y elevación de interleuquina 6, significativa con respecto al Grupo C. Grupo C: 32 pacientes que no presentaron molestias ni elevación de IL-6, ni elevación de amilasas. El pico más importante de IL-6 se presentó a las 24 horas. La pancreatitis aguda post ERCP es un excelente modelo para la evaluación de los eventos inflamatorios tempranos y además la IL6 es un indicador diagnóstico y pronóstico de pancreatitis aguda