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1.
Children (Basel) ; 11(7)2024 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-39062323

RESUMO

(1) Background: Acute pain in hospitalized children remains under-recognized and under-treated. Our objective is to benchmark pain assessment, documentation, treatment, and patient experience in children admitted to a US children's hospital. (2) Methods: A cross-sectional, mixed-method survey of pain for children hospitalized ≥24 h. Charts were reviewed for modalities of pain assessment and treatment for all inpatients. If pain was documented, patients/caregivers were surveyed regarding their experience with pain and its management. (3) Results: Chart review: All 107 patients had ≥1 pain score documented. A total of 47 patients had a pain score ≥0, 35 (74.5%) of whom had ≥1 moderate-severe score. Seventy (65.4%) patients received ≥1 intervention for pain, including medications from ≥1 class (e.g., opioids) (n = 55, 51.4%) and/or integrative/non-pharmacologic intervention(s) (n = 39, 36.4%). There were assessment and documentation gaps. Patient survey: A total of 39 (83.0%) interviews were attempted; 25 (53.2%) were completed. The worst pain was mostly caused by acute illness (n = 13, 52%) and painful procedures (n = 10, 40%). Suggestions for improvement included increasing the use of integrative modalities and optimizing patient-clinician communication. (4) Conclusions: All patients admitted ≥24 h had ≥1 pain score documented; however, gaps in documentation were common. Multimodal treatment and integrative modalities were underutilized. Procedures were a frequent cause of under-treated pain, prompting an institution-wide quality improvement project.

2.
Cornea ; 41(7): e16, 2022 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-35349536
3.
Cornea ; 41(5): 644-646, 2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-34935658

RESUMO

PURPOSE: The purpose of this study was to present a case of diffuse noncaseating granulomas involving the corneal stroma in a patient with ocular and pulmonary sarcoidosis. METHODS: This was a single case report. RESULTS: A 31-year-old female patient presented with a 6-year history of panuveitis of the right eye along with a history of pulmonary sarcoidosis and a conjunctival biopsy of the right eye that was reported as positive for sarcoidosis. At presentation to our clinic, the patient had band keratopathy, vascularization of the inferonasal cornea, and active anterior uveitis of the right eye. When the patient returned for a follow-up of 15 months after the initial presentation, the cornea of the right eye exhibited widespread stromal scarring and vascularization. Because of the corneal scarring, the patient underwent an implantation of a Boston type 1 keratoprosthesis in the right eye. Histopathological examination of the host corneal tissue removed at the time of the keratoprosthesis procedure revealed extensive noncaseating granulomas in the deep corneal stroma. The patient underwent penetrating keratoplasty 8 months later, and histopathological examination again demonstrated noncaseating granulomas, this time at the edges of the donor corneal graft used during the keratoprosthesis implantation. CONCLUSIONS: We present the histopathological evidence of sarcoidosis involving the corneal stroma. Interestingly, the stromal keratitis also subsequently involved the donor cornea tissue after the patient underwent a keratoprosthesis implantation. It seems that sarcoidosis is a rare cause of stromal keratitis.


Assuntos
Doenças da Córnea , Sarcoidose , Adulto , Córnea/patologia , Doenças da Córnea/diagnóstico , Doenças da Córnea/etiologia , Doenças da Córnea/cirurgia , Feminino , Humanos , Inflamação , Próteses e Implantes/efeitos adversos , Sarcoidose/complicações , Sarcoidose/diagnóstico
4.
F1000Res ; 10: 820, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-36212901

RESUMO

Background: Metagenomic sequencing has the potential to identify a wide range of pathogens in human tissue samples. Sarcoidosis is a complex disorder whose etiology remains unknown and for which a variety of infectious causes have been hypothesized. We sought to conduct metagenomic sequencing on cases of ocular and periocular sarcoidosis, none of them with previously identified infectious causes. Methods: Archival tissue specimens of 16 subjects with biopsies of ocular and periocular tissues that were positive for non-caseating granulomas were used as cases. Four archival tissue specimens that did not demonstrate non-caseating granulomas were also included as controls. Genomic DNA was extracted from tissue sections. DNA libraries were generated from the extracted genomic DNA and the libraries underwent next-generation sequencing. Results: We generated between 4.8 and 20.7 million reads for each of the 16 cases plus four control samples. For eight of the cases, we identified microbial pathogens that were present well above the background, with one potential pathogen identified for seven of the cases and two possible pathogens for one of the cases. Five of the eight cases were associated with bacteria ( Campylobacter concisus, Neisseria elongata, Streptococcus salivarius, Pseudopropionibacterium propionicum, and Paracoccus yeei), two cases with fungi ( Exophiala oligosperma, Lomentospora prolificans and Aspergillus versicolor) and one case with a virus (Mupapillomavirus 1). Interestingly, four of the five bacterial species are also part of the human oral microbiome. Conclusions: Using a metagenomic sequencing we identified possible infectious causes in half of the ocular and periocular sarcoidosis cases analyzed. Our findings support the proposition that sarcoidosis could be an etiologically heterogenous disease. Because these are previously banked samples, direct follow-up in the respective patients is impossible, but these results suggest that sequencing may be a valuable tool in better understanding the etiopathogenesis of sarcoidosis and in diagnosing and treating this disease.


Assuntos
Microbiota , Sarcoidose , Bactérias/genética , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Humanos , Metagenoma , Metagenômica/métodos , Microbiota/genética , Sarcoidose/diagnóstico , Sarcoidose/genética
5.
Pediatr Qual Saf ; 4(4): e182, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31572884

RESUMO

BACKGROUND: Family-centered rounds (FCRs) provide many benefits over traditional rounds, including higher patient satisfaction, and shared mental models among staff. These benefits can only be achieved when key members of the care team are present and engaged. We aimed to improve patient engagement and satisfaction with our existing bedside rounds by designing a new FCR process. METHODS: We conducted a needs assessment and formed a multidisciplinary FCR committee that identified appointment-based family-centered rounds (aFCRs) as a primary intervention. We designed, implemented, and iteratively refined an aFCR process. We tracked process metrics (rounds attendance by key participants), a balancing metric (time per patient), and outcome metrics (patient satisfaction domains) during the intervention and follow-up periods. RESULTS: After implementing aFCR, 65% of patients reported positive experience with rounds and communication. Rounds duration per patient was similar (9 versus 9.4 min). Nurse, subspecialist, and interpreter attendance on rounds was 72%, 60%, and 90%, respectively. We employed a Rounding Coordinator to complete the scheduling and communication required for successful aFCR. DISCUSSION: We successfully improved our rounding processes through the introduction of aFCR with the addition of a rounding coordinator. Our experience demonstrates one method to increase multidisciplinary team member attendance on rounds and patient satisfaction with physician communication in the inpatient setting.

6.
Transcult Psychiatry ; 56(3): 491-509, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30758257

RESUMO

Family caregivers (FCs) of people with mental illness (PMI) experience caregiving-related distress. These challenges tend to be greater for Asian American families due to acculturative stress and structural barriers to services. However, little is known about caregiving-related experiences among FCs of PMI within a cultural context. By using an exploratory approach, we examined the experience of caregiver distress and the influence of cultural values on caregiving in European American and Chinese American FCs. In collaboration with community-based agencies, a combination of convenience and snowball sampling methods were used to recruit Chinese American and European American caregivers who co-reside with PMIs. Two focus groups with each ethnic group with 57 participants (30 Chinese and 27 European American) were conducted. Thematic analysis indicates that FCs experience intense emotions, health/mental health problems, and a negative impact on their personal/social lives. Whereas Chinese American FCs reported shame, lack of knowledge, and over-protectiveness of PMIs, European American FCs reported the need for advocacy on behalf of the PMI. Findings indicate a need for: 1) greater awareness of the caregiving experience on wellbeing of FCs; 2) an understanding of how cultural values may influence caregiver experience; and 3) developing culturally relevant prevention and intervention services that can support FCs from diverse cultural contexts.


Assuntos
Asiático/psicologia , Cuidadores/psicologia , Transtornos Mentais/terapia , População Branca/psicologia , Aculturação , Adaptação Psicológica , Adulto , Idoso , Feminino , Grupos Focais , Humanos , Entrevistas como Assunto , Masculino , Pessoa de Meia-Idade , Pesquisa Qualitativa , Estigma Social , Estresse Psicológico , Estados Unidos
7.
Pain ; 158(1): 103-109, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27749608

RESUMO

Evaluate laser acupuncture (LA) as an adjuvant therapy in pain management during percutaneous kidney biopsy procedure in children and adolescents. This prospective, double-blinded, randomized controlled trial enrolled patients aged 7 to 26 years admitted to a children's hospital for percutaneous kidney biopsy. Patients received LA to treatment points (acupuncture group) or sham points (control group) before the procedure. The laser delivered a dose of 42 J/cm over 10 acupoints. Patients and parents rated the pain during and after the biopsy, and change in pain scores were calculated for each patient. Anxiety, vital signs, sedation medication, and patient's biopsy experience were secondary outcomes. Sixty-nine treatments (33 in the acupuncture group and 36 in the control group) were eligible for analysis. Patients in the acupuncture group reported a significantly improved change in the pain score after the biopsy compared with the controls (0.8 vs -0.5, P = 0.044). Patients in the acupuncture group had a statistically significant decrease in procedure vital signs including heart rate (-1.8 vs 5.6, P = 0.043) and respiratory rate (-2.4 vs 0.4, P = 0.045) when compared with controls. Parents also perceived a correspondingly greater improvement in their child's pain for those in the acupuncture group compared with the controls (2.3 vs 0.3, P = 0.04). Adjunctive LA significantly improved pain after pediatric percutaneous kidney biopsies.


Assuntos
Terapia por Acupuntura/métodos , Biópsia/efeitos adversos , Terapia a Laser/métodos , Manejo da Dor , Dor/etiologia , Adolescente , Adulto , Criança , Método Duplo-Cego , Feminino , Humanos , Nefropatias/diagnóstico , Masculino , Estudos Retrospectivos , Estatísticas não Paramétricas , Resultado do Tratamento , Adulto Jovem
8.
PLoS One ; 11(8): e0159405, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27482713

RESUMO

Netrin-1 is an essential extracellular chemoattractant that signals through its receptor DCC to guide commissural axon extension in the embryonic spinal cord. DCC directs the organization of F-actin in growth cones by activating an intracellular protein complex that includes the Rho GTPase Cdc42, a critical regulator of cell polarity and directional migration. To address the spatial distribution of signaling events downstream of netrin-1, we expressed the FRET biosensor Raichu-Cdc42 in cultured embryonic rat spinal commissural neurons. Using FLIM-FRET imaging we detected rapid activation of Cdc42 in neuronal growth cones following application of netrin-1. Investigating the signaling mechanisms that control Cdc42 activation by netrin-1, we demonstrate that netrin-1 rapidly enriches DCC at the leading edge of commissural neuron growth cones and that netrin-1 induced activation of Cdc42 in the growth cone is blocked by inhibiting src family kinase signaling. These findings reveal the activation of Cdc42 in embryonic spinal commissural axon growth cones and support the conclusion that src family kinase activation downstream of DCC is required for Cdc42 activation by netrin-1.


Assuntos
Transferência Ressonante de Energia de Fluorescência/métodos , Cones de Crescimento/ultraestrutura , Microscopia de Fluorescência/métodos , Fatores de Crescimento Neural/análise , Medula Espinal/embriologia , Proteínas Supressoras de Tumor/análise , Proteína cdc42 de Ligação ao GTP/análise , Animais , Células Cultivadas , Receptor DCC , Cones de Crescimento/metabolismo , Microdissecção , Fatores de Crescimento Neural/metabolismo , Netrina-1 , Ratos Sprague-Dawley , Receptores de Superfície Celular/análise , Receptores de Superfície Celular/metabolismo , Transdução de Sinais , Medula Espinal/citologia , Medula Espinal/metabolismo , Medula Espinal/ultraestrutura , Proteínas Supressoras de Tumor/metabolismo , Proteína cdc42 de Ligação ao GTP/metabolismo , Quinases da Família src/metabolismo
9.
Cell Rep ; 12(7): 1099-106, 2015 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-26257176

RESUMO

Netrin-1 regulates cell migration and adhesion during the development of the nervous system, vasculature, lung, pancreas, muscle, and mammary gland. It is also proposed to function as a dependence ligand that inhibits apoptosis; however, studies disagree regarding whether netrin-1 loss-of-function mice exhibit increased cell death. Furthermore, previously studied netrin-1 loss-of-function gene-trap mice express a netrin-1-ß-galactosidase protein chimera with potential for toxic gain-of-function effects, as well as a small amount of wild-type netrin-1 protein. To unambiguously assess loss of function, we generated netrin-1 floxed and netrin-1 null mouse lines. Netrin-1(-/-) mice die earlier and exhibit more severe axon guidance defects than netrin-1 gene-trap mice, revealing that complete loss of function is more severe than previously reported. Netrin-1(-/-) embryos also exhibit increased expression of the netrin receptors DCC and neogenin that are proposed dependence receptors; however, increased apoptosis was not detected, inconsistent with netrin-1 being an essential dependence receptor ligand in the embryonic spinal cord.


Assuntos
Apoptose , Axônios/metabolismo , Embrião de Mamíferos/metabolismo , Fatores de Crescimento Neural/genética , Proteínas Supressoras de Tumor/genética , Animais , Axônios/patologia , Embrião de Mamíferos/patologia , Feminino , Morte Fetal , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Fatores de Crescimento Neural/metabolismo , Receptores de Netrina , Netrina-1 , Gravidez , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/metabolismo , Proteínas Supressoras de Tumor/metabolismo
10.
Neurology ; 80(10): 957-62, 2013 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-23325904

RESUMO

Hospitalist medicine has gown rapidly over the past decade in response to increasing complexity of hospitalized patients, financial pressures, and a national call for improved quality and safety outcomes. An adult neurohospitalist model of care has recently emerged to address these factors and the need for inpatient neurologists who offer expertise and immediate availability for emergent neurologic conditions such as acute stroke and status epilepticus. Similarly, hospitalized children with acute neurologic disorders require a uniquely high level of care, which increasingly cannot be delivered by pediatric neurologists with busy outpatient practices or by pediatric hospitalists without specialized training. This perspective explores the concept of a pediatric neurohospitalist model of care, including the potential impact on quality of care, hospitalization costs, and education.


Assuntos
Médicos Hospitalares , Hospitais Pediátricos , Neurologia , Pediatria , Criança , Criança Hospitalizada , Humanos , Recursos Humanos
11.
Biomacromolecules ; 13(9): 2958-63, 2012 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-22913295

RESUMO

We report the development of a photoreversible cell culture substrate. We demonstrate the capacity to modify the adhesivity of the substrate using light, altering its capacity to support cell growth. Polyelectrolyte multilayers (PEMs) were used to produce tunable substrates of different thickness and matrix stiffness, which have different intrinsic capacities to support cell adhesion and survival. Surfaces were top-coated with a poly(acrylic acid)-poly(allylamine hydrochloride) polyelectrolyte bilayer functionalized with a small fraction (<1%) of an azobenzene-based photoswitchable sidegroup, which included the cell-adhesive three-amino-acid peptide RGD. Irradiation with light-induced geometric switching of the azo bond, resulting in changes to RGD exposure and consequently to cell adhesion and survival, was investigated on a variety of surfaces of different thickness and stiffness. Substrate stiffness, as modified by the thickness, had a significant influence on the adhesion of NIH 3T3 cells, consistent with previous studies. However, by disrupting the isomerization state of the azobenzene-linked RGD and exposing it to the surface, cell adhesion and survival could be enhanced up to 40% when the positioning of the RGD peptide was manipulated on the softest substrates. These findings identify permissive, yet less-than-optimal, cell culture substrate conditions that can be substantially enhanced using noninvasive modification of the substrate triggered by light. Indeed, where cell adhesion was tuned to be suboptimal under baseline conditions, the light-induced triggers displayed the most enhanced effect, and identification of this 'Goldilocks zone' was key to enabling light triggering.


Assuntos
Acrilatos/síntese química , Alilamina/análogos & derivados , Compostos Azo/química , Materiais Revestidos Biocompatíveis/síntese química , Oligopeptídeos/química , Acrilatos/farmacologia , Alilamina/síntese química , Alilamina/farmacologia , Animais , Adesão Celular/efeitos dos fármacos , Adesão Celular/efeitos da radiação , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/efeitos da radiação , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Materiais Revestidos Biocompatíveis/farmacologia , Concentração de Íons de Hidrogênio , Luz , Camundongos , Células NIH 3T3 , Processos Fotoquímicos , Espectrofotometria , Propriedades de Superfície
12.
Biomaterials ; 33(24): 5841-7, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22632764

RESUMO

The capacity to engineer the extracellular matrix is critical to better understand cell function and to design optimal cellular environments to support tissue engineering, transplantation and repair. Stacks of adsorbed polymers can be engineered as soft wet three dimensional matrices, with properties tailored to support cell survival and growth. Here, we have developed a combinatorial method to generate coatings that self assemble from solutions of polyelectrolytes in water, layer by layer, to produce a polyelectrolyte multilayer (PEM) coating that has enabled high-throughput screening for cellular biocompatibility. Two dimensional combinatorial PEMs were used to rapidly identify assembly conditions that promote optimal cell survival and viability. Conditions were first piloted using a cell line, human embryonic kidney 293 cells (HEK 293), and subsequently tested using primary cultures of embryonic rat spinal commissural neurons. Cell viability was correlated with surface energy (wettability), modulus (matrix stiffness), and surface charge of the coatings.Our findings indicate that the modulus is a crucial determinant of the capacity of a surface to inhibit or support cell survival.


Assuntos
Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/metabolismo , Ensaios de Triagem em Larga Escala/instrumentação , Teste de Materiais/instrumentação , Resinas Acrílicas/química , Resinas Acrílicas/metabolismo , Animais , Diferenciação Celular , Linhagem Celular , Sobrevivência Celular , Células Cultivadas , Desenho de Equipamento , Matriz Extracelular/química , Matriz Extracelular/metabolismo , Células HEK293 , Ensaios de Triagem em Larga Escala/métodos , Humanos , Teste de Materiais/métodos , Neurônios/citologia , Poliaminas/química , Poliaminas/metabolismo , Ratos
13.
J Biol Chem ; 286(28): 25098-107, 2011 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-21613222

RESUMO

Mcl-1, a pro-survival member of the Bcl-2 family located at the mitochondrial outer membrane, is subject to constitutive ubiquitylation by the Bcl-2 homology 3-only E3 ligase, Mule/Lasu1, resulting in rapid steady-state degradation via the proteasome. Insertion of newly synthesized Mcl-1 into the mitochondrial outer membrane is dependent on its C-terminal transmembrane segment, but once inserted, the N terminus of a portion of the Mcl-1 molecules can be subject to proteolytic processing. Remarkably, this processing requires an intact electrochemical potential across the inner membrane. Three lines of evidence directed at the endogenous protein, however, indicate that the resulting Mcl-1ΔN isoform resides in the outer membrane: (i) full-length Mcl-1 and Mcl-1ΔN resist extraction by alkali but are accessible to exogenous protease; (ii) almost the entire populations of Mcl-1 and Mcl-1ΔN are accessible to the membrane-impermeant Cys-reactive agent 4-acetamido-4'-[(iodoacetyl)amino]stilbene-2,2'-disulfonic acid; and (iii) Mcl-1 and Mcl-1ΔN exhibit equivalent chemical cross-linking to Bak in intact mitochondria, an Mcl-1 binding partner located in the outer membrane. In addition to the Mule Bcl-2 homology 3 domain, we show that interaction between Mcl-1 and Mule also requires the extreme N terminus of Mcl-1, which is lacking in Mcl-1ΔN. Thus, Mcl-1ΔN does not interact with Mule, exhibits reduced steady-state ubiquitylation, evades the hyper-rapid steady-state degradation that is observed for full-length Mcl-1 in response to treatments that limit global protein synthesis, and confers resistance to UV stress-induced cell death.


Assuntos
Mitocôndrias/metabolismo , Membranas Mitocondriais/metabolismo , Proteólise , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Animais , Sítios de Ligação , Morte Celular/fisiologia , Morte Celular/efeitos da radiação , Células HeLa , Humanos , Camundongos , Camundongos Knockout , Mitocôndrias/genética , Proteína de Sequência 1 de Leucemia de Células Mieloides , Células NIH 3T3 , Biossíntese de Proteínas/fisiologia , Biossíntese de Proteínas/efeitos da radiação , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Supressoras de Tumor , Ubiquitina-Proteína Ligases/genética , Ubiquitinação/fisiologia , Ubiquitinação/efeitos da radiação , Raios Ultravioleta
14.
Development ; 138(11): 2153-69, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21558366

RESUMO

Netrins are secreted proteins that were first identified as guidance cues, directing cell and axon migration during neural development. Subsequent findings have demonstrated that netrins can influence the formation of multiple tissues, including the vasculature, lung, pancreas, muscle and mammary gland, by mediating cell migration, cell-cell interactions and cell-extracellular matrix adhesion. Recent evidence also implicates the ongoing expression of netrins and netrin receptors in the maintenance of cell-cell organisation in mature tissues. Here, we review the mechanisms involved in netrin signalling in vertebrate and invertebrate systems and discuss the functions of netrin signalling during the development of neural and non-neural tissues.


Assuntos
Proteínas do Tecido Nervoso/metabolismo , Receptores de Superfície Celular/metabolismo , Animais , Axônios/fisiologia , Adesão Celular , Moléculas de Adesão Celular/metabolismo , Comunicação Celular , Diferenciação Celular , Movimento Celular , Receptor DCC , Humanos , Ligantes , Proteínas de Membrana/metabolismo , Proteínas do Tecido Nervoso/química , Sistema Nervoso/embriologia , Sistema Nervoso/metabolismo , Receptores de Netrina , Neurônios/fisiologia , Transdução de Sinais , Proteínas Supressoras de Tumor/metabolismo
15.
Development ; 135(17): 2855-64, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18653556

RESUMO

Molecular cues, such as netrin 1, guide axons by influencing growth cone motility. Rho GTPases are a family of intracellular proteins that regulate the cytoskeleton, substrate adhesion and vesicle trafficking. Activation of the RhoA subfamily of Rho GTPases is essential for chemorepellent axon guidance; however, their role during axonal chemoattraction is unclear. Here, we show that netrin 1, through its receptor DCC, inhibits RhoA in embryonic spinal commissural neurons. To determine whether netrin 1-mediated chemoattraction requires Rho function, we inhibited Rho signaling and assayed axon outgrowth and turning towards netrin 1. Additionally, we examined two important mechanisms that influence the guidance of axons to netrin 1: substrate adhesion and transport of the netrin receptor DCC to the plasma membrane. We found that inhibiting Rho signaling increased plasma membrane DCC and adhesion to substrate-bound netrin 1, and also enhanced netrin 1-mediated axon outgrowth and chemoattractive axon turning. Conversely, overexpression of RhoA or constitutively active RhoA inhibited axonal responses to netrin 1. These findings provide evidence that Rho signaling reduces axonal chemoattraction to netrin 1 by limiting the amount of plasma membrane DCC at the growth cone, and suggest that netrin 1-mediated inhibition of RhoA activates a positive-feedback mechanism that facilitates chemoattraction to netrin 1. Notably, these findings also have relevance for CNS regeneration research. Inhibiting RhoA promotes axon regeneration by disrupting inhibitory responses to myelin and the glial scar. By contrast, we demonstrate that axon chemoattraction to netrin 1 is not only maintained but enhanced, suggesting that this might facilitate directing regenerating axons to appropriate targets.


Assuntos
Axônios/metabolismo , Membrana Celular/metabolismo , Quimiotaxia/efeitos dos fármacos , Fatores de Crescimento Neural/farmacologia , Receptores de Superfície Celular/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Proteínas Supressoras de Tumor/farmacologia , Proteína rhoA de Ligação ao GTP/antagonistas & inibidores , Animais , Axônios/efeitos dos fármacos , Axônios/enzimologia , Adesão Celular/efeitos dos fármacos , Membrana Celular/efeitos dos fármacos , Receptor DCC , Embrião de Mamíferos/citologia , Embrião de Mamíferos/enzimologia , Ativação Enzimática/efeitos dos fármacos , Feminino , Cones de Crescimento/efeitos dos fármacos , Cones de Crescimento/enzimologia , Humanos , Netrina-1 , Proteína Quinase C/metabolismo , Transporte Proteico/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , Quinases Associadas a rho/metabolismo
16.
J Neurosci ; 28(15): 3920-4, 2008 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-18400890

RESUMO

During development, axons are directed to their targets by extracellular guidance cues. The axonal response to the guidance cue netrin-1 is profoundly influenced by the concentration of cAMP within the growth cone. In some cases, cAMP affects the sensitivity of the growth cone to netrin-1, whereas in others it changes the response to netrin-1 from attraction to repulsion. The effects of cAMP on netrin-1 action are well accepted, but the critical issue of whether cAMP production is activated by a netrin-1 induced signaling cascade remains uncertain. A previous report has suggested that axon guidance in response to netrin-1 requires cAMP production mediated by soluble adenyl cyclase (sAC). We have used genetic, molecular and biochemical strategies to assess this issue. Surprisingly, we found only extremely weak expression of sAC in embryonic neurons and determined that, under conditions where netrin-1 directs axonal pathfinding, exposure to netrin-1 does not alter cAMP levels. Furthermore, although netrin-1-deficient mice exhibit major axon guidance defects, we show that pathfinding is normal in sAC-null mice. Therefore, although cAMP can alter the response of axons to netrin-1, we conclude that netrin-1 does not alter cAMP levels in axons attracted by this cue, and that sAC is not required for axon attraction to netrin-1.


Assuntos
Adenilil Ciclases/fisiologia , Axônios/efeitos dos fármacos , Axônios/fisiologia , Cones de Crescimento/efeitos dos fármacos , Cones de Crescimento/fisiologia , Fatores de Crescimento Neural/farmacologia , Proteínas Supressoras de Tumor/farmacologia , Adenilil Ciclases/química , Adenilil Ciclases/deficiência , Adenilil Ciclases/metabolismo , Animais , Células Cultivadas , AMP Cíclico/metabolismo , AMP Cíclico/fisiologia , Embrião de Mamíferos/metabolismo , Embrião de Mamíferos/fisiologia , Gânglios Espinais/citologia , Gânglios Espinais/embriologia , Humanos , Camundongos , Camundongos Knockout , Netrina-1 , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Ratos , Ratos Sprague-Dawley , Proteínas Recombinantes/farmacologia , Solubilidade
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