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An examination of women's experience on public transport in Bangladesh and Cambodia found that victimization does reduce perceived safety or transport use. In a cultural context where women are socialized to fear and avoid public spaces, experiencing victimization may confirm rather than change previous beliefs. Moreover, it is possible that the participants' use of public transport was driven by necessity rather than choice and that they were unable to change travel patterns in response to victimization. These findings underscore the importance of targeting public violence toward women and the broader societal norms that limit their participation in public life.
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Defective mitochondrial dynamics in axons have been linked to both developmental and late-onset neurological disorders. Axonal trafficking is in large part governed by the microtubule motors kinesin-1 and cytoplasmic dynein 1 (dynein). Dynein is the primary retrograde transport motor in axons, and mutations in dynein and many of its regulators also cause neurological diseases. Depletion of LIS1, famous for linking dynein deregulation to lissencephaly (smooth brain), in adult mice leads to severe neurological phenotypes, demonstrating post-developmental roles. LIS1 stimulates retrograde transport of acidic organelles in cultured adult rat dorsal root ganglion (DRG) axons but findings on its role in mitochondrial trafficking have been inconsistent and have not been reported for adult axons. Here we report that there is an increased number of mitochondria in cross-sections of sciatic nerve axons from adult LIS1+/- mice. This is probably related to reduced dynein activity as axons from adult rat nerves exposed to the dynein inhibitor, ciliobrevin D also had increased numbers of mitochondria. Moreover, LIS1 overexpression (OE) in cultured adult rat DRG axons stimulated retrograde mitochondrial transport while LIS1 knockdown (KD) or expression of a LIS1 dynein-binding mutant (LIS1-K147A) inhibited retrograde transport, as did KD of dynein heavy chain (DHC). These findings are consistent with our report on acidic organelles. However, KD of NDEL1, a LIS1 and dynein binding protein, or expression of a LIS1 NDEL1-binding mutant (LIS1-R212A) also dramatically impacted retrograde mitochondrial transport, which was not the case for acidic organelles. Manipulations that disrupted retrograde mitochondrial transport also increased the average length of axonal mitochondria, suggesting a role for dynein in fusion or fission events. Our data point to cargo specificity in NDEL1 function and raise the possibility that defects in the LIS1/NDEL1 dynein regulatory pathway could contribute to mitochondrial diseases with axonal pathologies.
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The COVID-19 pandemic has negatively impacted the health of people from communities of color and people of limited socioeconomic means in a disproportionate way due to social determinants of health (SDoH). The Centers for Disease Control defines SDoH as the "conditions in the places where people live, learn, work, and play that affect a wide range of health and quality-of life-risks and outcomes." A related construct, social determinants of learning (SDoL), includes contextual conditions and variables that impact students' ability to optimally participate in their education, including academic and clinical development. SDoL directly impact students' ability to participate in the educational process. During the COVID-19 pandemic, students struggling with SDoH and, by extension SDoL, may be more likely to have sick family members, caregiving responsibilities, food and housing insecurity, and obligations to supplement lost family wages. SDoL are also influenced by individual experiences within and outside of the classroom. Beyond bringing this matter to the attention of our profession, especially clinical and academic educators, we must take action to reach and support students who are at higher academic risk due to the SDoL. The purpose of this paper is to (1) define SDoL, (2) explain how SDoL are impacting doctor of physical therapy and physical therapist assistant students, and (3) discuss actions that physical therapists and physical therapist assistants can take to mitigate the effects of SDoL on current doctor of physical therapy and physical therapist assistant students. IMPACT: This Perspective is one of the first explorations of how SDoL affect physical therapy students during the pandemic and provides concrete suggestions on how educators in both academic and clinical settings can help students succeed when they are negatively affected by SDoL.
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Atitude do Pessoal de Saúde , COVID-19/epidemiologia , Fisioterapeutas/psicologia , Especialidade de Fisioterapia/educação , Determinantes Sociais da Saúde/estatística & dados numéricos , Estudantes de Ciências da Saúde/psicologia , Humanos , Relações InterprofissionaisRESUMO
Age estimation is one of the crucial first steps in the identification of human skeletal remains in both forensic and archeological contexts. In the postnatal period, age is traditionally estimated from dental development or skeletal growth, typically long bone diaphyseal length. However, in many occasions other methods are required. This study provides alternative means of estimating age of juvenile remains from the size of several cranial bones and the mandible. A sample of 185 identified juvenile skeletons between birth and 13 years of age from two European collections were used (Lisbon and Spitalfields). Measurements of the frontal, occipital-lateralis, occipital-basilaris, occipital-squamous, zygomatic, maxilla, and mandible were used to calculate classical calibration regression formulae for the sexes combined. The sample was divided into three age groups birth-2 years, 2-6 years, and 2-12.9 years, depending on bone and its growth trajectory. For all the bones, measurements of the youngest age groups yielded the most precise age estimates. The vault bones on average yielded the best performing models, with the frontal bone having the most precise of all. The mandible performed on par with the best performing cranial bones, particularly in individuals under the age of 2 years. This study provides one of the most comprehensive approaches to juvenile age estimation based on bones of the skull, providing a resource that potentially can help estimate age of juvenile skeletons from a variety of circumstances.
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Determinação da Idade pelo Esqueleto/métodos , Cefalometria , Menores de Idade , Crânio/anatomia & histologia , Crânio/crescimento & desenvolvimento , Restos Mortais , Criança , Pré-Escolar , Inglaterra , Ossos Faciais/anatomia & histologia , Ossos Faciais/crescimento & desenvolvimento , Feminino , Antropologia Forense , Humanos , Lactente , Masculino , Mandíbula/anatomia & histologia , Mandíbula/crescimento & desenvolvimento , PortugalRESUMO
BACKGROUND: There is convincing evidence that dancers suffer injuries to the triceps surae musculature. Research on the immediate effects of dry needling (DN) is limited, and it is important to understand the acute effects of this treatment prior to performance. PURPOSE: The purpose of this pilot study was to assess the immediate effects of DN on myofascial trigger points in terms of skin surface temperature, pain, active and passive range of motion, and torque production in the triceps surae of ballet dancers. STUDY DESIGN: Randomized, double-blinded pilot study. METHODS: Professional ballet dancers that fit inclusion and exclusion criteria (n=11) were randomly assigned to an experimental or control group. The dancers had three pre-determined standard point (SP) measurement spots that were used as a baseline for surface temperature comparisons. The dancers were also palpated for trigger point (TP) spots. Both SP and TP spots were marked for future measurements. The experimental group received DN, while the control group received sham DN (SHAM) to their bilateral calves at the TP spots. Immediately prior to and following treatment, both DN and SHAM groups were tested for skin surface temperature, pain, range of motion, and plantar flexion torque by blinded assessors. Paired t-tests and independent t-tests were performed to examine for differences between groups. RESULTS: The surface temperature for the TP was higher than the SP measurements prior to intervention (Right calf p= .014; Left calf p= .031). There were no significant changes in VAS scale reported pain and ROM. The plantar flexion torque measurements showed an increase in the DN group of the left calf at the angular velocity of 60 degrees/sec. CONCLUSION: This was a unique pilot study examining the acute effects of DN on professional ballet dancers. The results were limited due to low sample size. However, the methodology for this study and surface temperature results invites future research. LEVEL OF EVIDENCE: Level 1b.
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Inhibition of histone deacetylase 6 (HDAC6) was shown to support axon growth on the nonpermissive substrates myelin-associated glycoprotein (MAG) and chondroitin sulfate proteoglycans (CSPGs). Though HDAC6 deacetylates α-tubulin, we find that another HDAC6 substrate contributes to this axon growth failure. HDAC6 is known to impact transport of mitochondria, and we show that mitochondria accumulate in distal axons after HDAC6 inhibition. Miro and Milton proteins link mitochondria to motor proteins for axon transport. Exposing neurons to MAG and CSPGs decreases acetylation of Miro1 on Lysine 105 (K105) and decreases axonal mitochondrial transport. HDAC6 inhibition increases acetylated Miro1 in axons, and acetyl-mimetic Miro1 K105Q prevents CSPG-dependent decreases in mitochondrial transport and axon growth. MAG- and CSPG-dependent deacetylation of Miro1 requires RhoA/ROCK activation and downstream intracellular Ca2+ increase, and Miro1 K105Q prevents the decrease in axonal mitochondria seen with activated RhoA and elevated Ca2+ These data point to HDAC6-dependent deacetylation of Miro1 as a mediator of axon growth inhibition through decreased mitochondrial transport.
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Desacetilase 6 de Histona/genética , Mitocôndrias/metabolismo , Neurônios/metabolismo , Proteínas rho de Ligação ao GTP/genética , Quinases Associadas a rho/genética , Acetilação/efeitos dos fármacos , Animais , Transporte Axonal/efeitos dos fármacos , Transporte Axonal/genética , Cálcio/metabolismo , Proteoglicanas de Sulfatos de Condroitina/farmacologia , Feminino , Gânglios Espinais/citologia , Gânglios Espinais/efeitos dos fármacos , Gânglios Espinais/metabolismo , Regulação da Expressão Gênica , Desacetilase 6 de Histona/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Mitocôndrias/efeitos dos fármacos , Glicoproteína Associada a Mielina/farmacologia , Neurônios/citologia , Neurônios/efeitos dos fármacos , Cultura Primária de Células , Ratos , Ratos Sprague-Dawley , Transdução de Sinais , Proteínas rho de Ligação ao GTP/metabolismo , Quinases Associadas a rho/metabolismoRESUMO
Single-molecule cytoplasmic dynein function is well understood, but there are major gaps in mechanistic understanding of cellular dynein regulation. We reported a mode of dynein regulation, force adaptation, where lipid droplets adapt to opposition to motion by increasing the duration and magnitude of force production, and found LIS1 and NudEL to be essential. Adaptation reflects increasing NudEL-LIS1 utilization; here, we hypothesize that such increasing utilization reflects CDK5-mediated NudEL phosphorylation, which increases the dynein-NudEL interaction, and makes force adaptation possible. We report that CDK5, 14-3-3ε, and CDK5 cofactor KIAA0528 together promote NudEL phosphorylation and are essential for force adaptation. By studying the process in COS-1 cells lacking Tau, we avoid confounding neuronal effects of CDK5 on microtubules. Finally, we extend this in vivo regulatory pathway to lysosomes and mitochondria. Ultimately, we show that dynein force adaptation can control the severity of lysosomal tug-of-wars among other intracellular transport functions involving high force.
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Proteínas 14-3-3/metabolismo , Quinase 5 Dependente de Ciclina/metabolismo , Dineínas do Citoplasma/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , 1-Alquil-2-acetilglicerofosfocolina Esterase/genética , 1-Alquil-2-acetilglicerofosfocolina Esterase/metabolismo , Proteínas 14-3-3/genética , Animais , Fenômenos Biomecânicos , Células COS , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Chlorocebus aethiops , Quinase 5 Dependente de Ciclina/genética , Gotículas Lipídicas/metabolismo , Lisossomos/metabolismo , Proteínas Associadas aos Microtúbulos/genética , Microtúbulos/metabolismo , Mitocôndrias/metabolismo , RNA Interferente Pequeno/metabolismoRESUMO
Using an online survey, this study explored the impact of participation in unpaid clinical placements on the financial wellbeing of 160 nursing students attending an Australian university. The research found that the majority of respondents struggle financially during clinical placements, yet are financially adequate or secure outside of semester or during normal periods of study. Increased transport costs and loss of income are the most significant financial stressors during this time, with additional meals, work-appropriate clothing, purchasing additional resources and materials, and childcare costs other causes of financial stress. Most students used savings, budgeting, borrowing, and changed expenditure patterns to cope with the financial impact of unpaid placement. These findings have important implications for the ability of students to successfully complete their nursing degree and draw into question the equity of unpaid clinical placements as a formal degree requirement. However, while participation in unpaid clinical placements can impact financial well-being in the short term, participation does have the potential to increase the financial resilience of students over time, as students learn and grow from these experiences. To achieve this, however, greater attention must be placed on the financial support and personal finance education available for nursing students.
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Estágio Clínico/economia , Financiamento Pessoal/economia , Estresse Psicológico/psicologia , Estudantes de Enfermagem/psicologia , Adolescente , Adulto , Austrália , Feminino , Humanos , Internet , Masculino , Inquéritos e Questionários , Adulto JovemRESUMO
The fumarate ester dimethyl fumarate (DMF) has been introduced recently as a treatment for relapsing remitting multiple sclerosis (RRMS), a chronic inflammatory condition that results in neuronal demyelination and axonal loss. DMF is known to act by depleting intracellular glutathione and modifying thiols on Keap1 protein, resulting in the stabilization of the transcription factor Nrf2, which in turn induces the expression of antioxidant response element genes. We have previously shown that DMF reacts with a wide range of protein thiols, suggesting that the complete mechanisms of action of DMF are unknown. Here, we investigated other intracellular thiol residues that may also be irreversibly modified by DMF in neurons and astrocytes. Using mass spectrometry, we identified 24 novel proteins that were modified by DMF in neurons and astrocytes, including cofilin-1, tubulin and collapsin response mediator protein 2 (CRMP2). Using an in vitro functional assay, we demonstrated that DMF-modified cofilin-1 loses its activity and generates less monomeric actin, potentially inhibiting its cytoskeletal remodeling activity, which could be beneficial in the modulation of myelination during RRMS. DMF modification of tubulin did not significantly impact axonal lysosomal trafficking. We found that the oxygen consumption rate of N1E-115 neurons and the levels of proteins related to mitochondrial energy production were only slightly affected by the highest doses of DMF, confirming that DMF treatment does not impair cellular respiratory function. In summary, our work provides new insights into the mechanisms supporting the neuroprotective and remyelination benefits associated with DMF treatment in addition to the antioxidant response by Nrf2.
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Astrócitos/metabolismo , Cisteína/efeitos dos fármacos , Fumarato de Dimetilo/farmacologia , Fator 2 Relacionado a NF-E2/metabolismo , Neurônios/metabolismo , Células 3T3-L1 , Animais , Astrócitos/citologia , Astrócitos/efeitos dos fármacos , Células Cultivadas , Cofilina 1/química , Cofilina 1/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular , Espectrometria de Massas , Camundongos , Proteínas do Tecido Nervoso/química , Proteínas do Tecido Nervoso/metabolismo , Neurônios/citologia , Neurônios/efeitos dos fármacos , Ratos , Tubulina (Proteína)/química , Tubulina (Proteína)/metabolismoRESUMO
Transport of late endosomes and lysosome-related organelles (LE/LROs) in axons is essential for supplying synaptic cargoes and for removing damaged macromolecules. Defects in this system are implicated in a range of human neurodegenerative and neurodevelopmental disorders. The findings reported here identify a novel mechanism regulating LE/LRO transport based on the coordinated coupling of microtubule motors and vesicle coat proteins to the neuron-enriched, transmembrane protein calcyon (Caly). We found that the cytoplasmic C-terminus of Caly pulled down proteins involved in microtubule-dependent transport (DIC, KIF5A, p150Glued, Lis1) and organelle biogenesis (AP-1 and AP-3) from the brain. In addition, RNA interference-mediated knockdown of Caly increased the percentage of static LE/LROs labeled by LysoTracker in cultured dorsal root ganglion axons. In contrast, overexpression of Caly stimulated movement of organelles positive for LysoTracker or the AP-3 cargo GFP-PI4KIIα. However, a Caly mutant (ATEA) that does not bind AP-3 was unable to pull down motor proteins from brain, and expression of the ATEA mutant failed to increase either LE/LRO flux or levels of associated dynein. Taken together, these data support the hypothesis that Caly is a multifunctional scaffolding protein that regulates axonal transport of LE/LROs by coordinately interacting with motor and vesicle coat proteins.
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Complexo 3 de Proteínas Adaptadoras/metabolismo , Axônios/metabolismo , Proteínas de Membrana/metabolismo , Microtúbulos/metabolismo , Proteínas Motores Moleculares/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Organelas/metabolismo , Animais , Linhagem Celular , Dineínas/metabolismo , Endossomos/metabolismo , Lisossomos/metabolismo , Proteínas de Membrana/química , Camundongos Endogâmicos C57BL , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Ratos , Proteínas rab5 de Ligação ao GTPRESUMO
Localization and translation of mRNAs within different subcellular domains provides an important mechanism to spatially and temporally introduce new proteins in polarized cells. Neurons make use of this localized protein synthesis during initial growth, regeneration and functional maintenance of their axons. Although the first evidence for protein synthesis in axons dates back to 1960s, improved methodologies, including the ability to isolate axons to purity, highly sensitive RNA detection methods and imaging approaches, have shed new light on the complexity of the transcriptome of the axon and how it is regulated. Moreover, these efforts are now uncovering new roles for locally synthesized proteins in neurological diseases and injury responses. In this Cell Science at a Glance article and the accompanying poster, we provide an overview of how axonal mRNA transport and translation are regulated, and discuss their emerging links to neurological disorders and neural repair.
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Axônios/metabolismo , Transporte de RNA/fisiologia , RNA Mensageiro/metabolismoRESUMO
LIS1 mutations cause lissencephaly (LIS), a severe developmental brain malformation. Much less is known about its role in the mature nervous system. LIS1 regulates the microtubule motor cytoplasmic dynein 1 (dynein), and as LIS1 and dynein are both expressed in the adult nervous system, Lis1 could potentially regulate dynein-dependent processes such as axonal transport. We therefore knocked out Lis1 in adult mice using tamoxifen-induced, Cre-ER-mediated recombination. When an actin promoter was used to drive Cre-ER expression (Act-Cre-ER), heterozygous Lis1 knockout (KO) caused no obvious change in viability or behavior, despite evidence of widespread recombination by a Cre reporter three weeks after tamoxifen exposure. In contrast, homozygous Lis1 KO caused the rapid onset of neurological symptoms in both male and female mice. One tamoxifen-dosing regimen caused prominent recombination in the midbrain/hindbrain, PNS, and cardiac/skeletal muscle within a week; these mice developed severe symptoms in that time frame and were killed. A different tamoxifen regimen resulted in delayed recombination in midbrain/hindbrain, but not in other tissues, and also delayed the onset of symptoms. This indicates that Lis1 loss in the midbrain/hindbrain causes the severe phenotype. In support of this, brainstem regions known to house cardiorespiratory centers showed signs of axonal dysfunction in KO animals. Transport defects, neurofilament (NF) alterations, and varicosities were observed in axons in cultured DRG neurons from KO animals. Because no symptoms were observed when a cardiac specific Cre-ER promoter was used, we propose a vital role for Lis1 in autonomic neurons and implicate defective axonal transport in the KO phenotype.
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1-Alquil-2-acetilglicerofosfocolina Esterase/metabolismo , Encéfalo/crescimento & desenvolvimento , Encéfalo/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , 1-Alquil-2-acetilglicerofosfocolina Esterase/genética , Animais , Transporte Axonal/fisiologia , Encéfalo/patologia , Células Cultivadas , Feminino , Gânglios Espinais/crescimento & desenvolvimento , Gânglios Espinais/metabolismo , Gânglios Espinais/patologia , Masculino , Camundongos Knockout , Proteínas Associadas aos Microtúbulos/genética , Doenças do Sistema Nervoso/metabolismo , Neuroglia/metabolismo , Neuroglia/patologia , Neurônios/metabolismo , Neurônios/patologia , FenótipoRESUMO
The neuron-enriched, endosomal protein Calcyon (Caly) regulates endocytosis and vesicle sorting, and is important for synaptic plasticity and brain development. In the current investigation of Caly interacting proteins in brain, the microtubule retrograde motor subunit, cytoplasmic dynein 1 heavy chain (DYNC1H), and microtubule structural proteins, α and ß tubulin, were identified as Caly associated proteins by MALDI-ToF/ToF. Direct interaction of the Caly-C terminus with dynein and tubulin was further confirmed in in vitro studies. In Cos-7 cells, mCherry-Caly moved along the microtubule network in organelles largely labeled by the late endosome marker Rab7. Expression of the dynein inhibitor CC1, produced striking alterations in Caly distribution, consistent with retrograde motors playing a prominent role in Caly localization and movement. In axons of cultured adult rat sensory neurons, Caly-positive organelles co-localized with dynein intermediate chain (DYNC1I1-isoform IC-1B) and the dynein regulator, lissencephaly 1 (LIS1), both of which co-precipitated from brain with the Caly C-terminus. Manipulation of dynein function in axons altered the motile properties of Caly indicating that Caly vesicles utilize the retrograde motor. Altogether, the current evidence for association with dynein motors raises the possibility that the endocytic and cargo sorting functions of Caly in neurons could be regulated by interaction with the microtubule transport system.
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Axônios/metabolismo , Movimento Celular , Dineínas/metabolismo , Endossomos/metabolismo , Proteínas de Membrana/metabolismo , Animais , Encéfalo/citologia , Encéfalo/metabolismo , Células COS , Chlorocebus aethiops , Camundongos , Microtúbulos/metabolismo , Ligação Proteica , Transporte Proteico , Ratos , Tubulina (Proteína)/metabolismoRESUMO
Diabetes is linked to an increased risk for colorectal cancer, but the mechanistic underpinnings of this clinically important effect are unclear. Here we describe an interaction between the microtubule motor cytoplasmic dynein, the adenomatous polyposis coli tumor suppressor protein (APC), and glycogen synthase kinase-3ß (GSK-3ß), which could shed light on this issue. GSK-3ß is perhaps best known for glycogen regulation, being inhibited downstream in an insulin-signaling pathway. However, the kinase is also important in many other processes. Mutations in APC that disrupt the regulation of ß-catenin by GSK-3ß cause colorectal cancer in humans. Of interest, both APC and GSK-3ß interact with microtubules and cellular membranes. We recently demonstrated that dynein is a GSK-3ß substrate and that inhibition of GSK-3ß promotes dynein-dependent transport. We now report that dynein stimulation in intestinal cells in response to acute insulin exposure (or GSK-3ß inhibition) is blocked by tumor-promoting isoforms of APC that reduce an interaction between wild-type APC and dynein. We propose that under normal conditions, insulin decreases dynein binding to APC to stimulate minus end-directed transport, which could modulate endocytic and secretory systems in intestinal cells. Mutations in APC likely impair the ability to respond appropriately to insulin signaling. This is exciting because it has the potential to be a contributing factor in the development of colorectal cancer in patients with diabetes.
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Polipose Adenomatosa do Colo/metabolismo , Neoplasias Colorretais/metabolismo , Dineínas do Citoplasma/metabolismo , Insulina/metabolismo , Animais , Linhagem Celular , Citoplasma/metabolismo , Complicações do Diabetes/metabolismo , Feminino , Genes APC/fisiologia , Quinase 3 da Glicogênio Sintase/metabolismo , Glicogênio Sintase Quinase 3 beta/genética , Glicogênio Sintase Quinase 3 beta/metabolismo , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microtúbulos/metabolismo , Ligação Proteica , Transdução de Sinais , beta Catenina/metabolismoRESUMO
Glycogen synthase kinase 3 (GSK-3) has been linked to regulation of kinesin-dependent axonal transport in squid and flies, and to indirect regulation of cytoplasmic dynein. We have now found evidence for direct regulation of dynein by mammalian GSK-3ß in both neurons and non-neuronal cells. GSK-3ß coprecipitates with and phosphorylates mammalian dynein. Phosphorylation of dynein intermediate chain (IC) reduces its interaction with Ndel1, a protein that contributes to dynein force generation. Two conserved residues, S87/T88 in IC-1B and S88/T89 in IC-2C, have been identified as GSK-3 targets by both mass spectrometry and site-directed mutagenesis. These sites are within an Ndel1-binding domain, and mutation of both sites alters the interaction of IC's with Ndel1. Dynein motility is stimulated by (i) pharmacological and genetic inhibition of GSK-3ß, (ii) an insulin-sensitizing agent (rosiglitazone) and (iii) manipulating an insulin response pathway that leads to GSK-3ß inactivation. Thus, our study connects a well-characterized insulin-signaling pathway directly to dynein stimulation via GSK-3 inhibition.
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Dineínas/metabolismo , Quinase 3 da Glicogênio Sintase/metabolismo , Sequência de Aminoácidos , Animais , Sítios de Ligação , Células COS , Proteínas de Transporte/metabolismo , Linhagem Celular Tumoral , Chlorocebus aethiops , Citoplasma/metabolismo , Dineínas/química , Dineínas/genética , Quinase 3 da Glicogênio Sintase/genética , Humanos , Insulina/metabolismo , Camundongos , Dados de Sequência Molecular , Ligação Proteica , Transporte Proteico , Sistemas do Segundo MensageiroRESUMO
CLINICAL SCENARIO: Over the past decade, sport-related concussions have received increased attention due to their frequency and severity over a wide range of athletics. Clinicians have developed return-to-play protocols to better manage concussions in young athletes; however, a standardized process projecting the length of recovery time after concussion has remained an elusive piece of the puzzle. The recovery times associated with such an injury once diagnosed can last anywhere from 1 wk to several months. Risk factors that could lead to protracted recovery times include a history of 1 or multiple concussions and a greater number, severity, and duration of symptoms after the injury. Examining the possible relationship between on-field or sideline signs and symptoms and recovery times would give clinicians the confident ability to properly treat and manage an athlete's recovery process in a more systematic manner. Furthermore, identifying factors after a head injury that may be predictive of protracted recovery times would be useful for athletes, parents, and coaches alike. FOCUSED CLINICAL QUESTION: Which on-field and sideline signs and symptoms affect length of recovery after concussion in high school and college athletes?
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Atletas , Traumatismos em Atletas/fisiopatologia , Traumatismos em Atletas/reabilitação , Concussão Encefálica/fisiopatologia , Concussão Encefálica/reabilitação , Recuperação de Função Fisiológica , Adolescente , Criança , Humanos , Escala de Gravidade do Ferimento , Fatores de Risco , Instituições Acadêmicas , Adulto JovemRESUMO
Lissencephaly is a human developmental brain abnormality caused by LIS1 haploinsufficiency. This disorder is in large part attributed to altered mitosis and migration in the developing brain. LIS1 and an interacting protein, NDEL1, bind to cytoplasmic dynein, a microtubule motor protein. While the tripartite complex is clearly important for developmental events, we are intrigued by the fact that Lis1 and Ndel1 expression remain high in the adult mouse nervous system. Dynein plays a crucial role in retrograde axonal transport, a process that is used by mature neurons. Here, we monitored acidic organelles moving in axons of adult rat sensory neurons to determine whether Lis1 and Ndel1 contribute to axonal transport. Lis1 RNAi significantly reduced axon transport of these organelles. Ndel1 RNAi had little impact, but combined Lis1 and Ndel1 RNAi caused a more severe phenotype than Lis1 RNAi alone, essentially shutting down transport. Lis1 overexpression stimulated retrograde transport, while a Lis1 dynein-binding mutant severely disrupted transport. Overexpression of Ndel1 or a Lis1 Ndel1-binding mutant only mildly perturbed transport. However, expressing a mutant Ndel1 lacking key phosphorylation sites shut down transport completely, as did a dominant-negative Cdk5 construct. We propose that, in axons, unphosphorylated Ndel1 inhibits the capacity of dynein to transport acidic organelles. Phosphorylation of Ndel1 by Cdk5 not only reduces this inhibition but also allows Lis1 to further stimulate the cargo transport capacity of dynein. Our data raise the possibility that defects in a Lis1/Ndel1 regulatory switch could contribute to neurodegenerative diseases linked to axonal pathology in adults.
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1-Alquil-2-acetilglicerofosfocolina Esterase/metabolismo , Axônios/metabolismo , Proteínas de Transporte/metabolismo , Quinase 5 Dependente de Ciclina/fisiologia , Dineínas/fisiologia , Proteínas Associadas aos Microtúbulos/metabolismo , Organelas/metabolismo , Fatores Etários , Animais , Axônios/fisiologia , Transporte Biológico/fisiologia , Células COS , Células Cultivadas , Chlorocebus aethiops , Dineínas/antagonistas & inibidores , Dineínas/metabolismo , Masculino , Camundongos , Organelas/fisiologia , Fosforilação , Ratos , Ratos Sprague-DawleyRESUMO
Lis1 and Ndel1 are essential for animal development. They interact directly with one another and with cytoplasmic dynein. The developing brain is especially sensitive to reduced Lis1 or Ndel1 levels, as both proteins influence spindle orientation, neural cell fate decisions, and neuronal migration. We report here that Lis1 and Ndel1 reduction in a mitotic cell line impairs prophase nuclear envelope (NE) invagination (PNEI). This dynein-dependent process facilitates NE breakdown (NEBD) and occurs before the establishment of the bipolar spindle. Ndel1 phosphorylation is important for this function, regulating binding to both Lis1 and dynein. Prophase cells in the ventricular zone (VZ) of embryonic day 13.5 Lis1(+/-) mouse brains show reduced PNEI, and the ratio of prophase to prometaphase cells is increased, suggesting an NEBD delay. Moreover, prophase cells in the VZ contain elevated levels of Ndel1 phosphorylated at a key cdk5 site. Our data suggest that a delay in NEBD in the VZ could contribute to developmental defects associated with Lis1-Ndel1 disruption.
Assuntos
1-Alquil-2-acetilglicerofosfocolina Esterase/metabolismo , Proteínas de Transporte/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Neurônios , Membrana Nuclear/metabolismo , Células-Tronco , 1-Alquil-2-acetilglicerofosfocolina Esterase/genética , Animais , Células COS , Proteínas de Transporte/genética , Ciclo Celular/fisiologia , Linhagem Celular , Chlorocebus aethiops , Complexo Dinactina , Dineínas/metabolismo , Feminino , Humanos , Masculino , Camundongos , Proteínas Associadas aos Microtúbulos/genética , Microtúbulos/metabolismo , Neurônios/citologia , Neurônios/fisiologia , Nocodazol/metabolismo , Fosforilação , Ligação Proteica , Ratos , Células-Tronco/citologia , Células-Tronco/metabolismo , Moduladores de Tubulina/metabolismoRESUMO
Diseases that affect the regulation of bone turnover can lead to skeletal fragility and increased fracture risk. Members of the TGF-beta superfamily have been shown to be involved in the regulation of bone mass. Activin A, a TGF-beta signaling ligand, is present at high levels in bone and may play a role in the regulation of bone metabolism. Here we demonstrate that pharmacological blockade of ligand signaling through the high affinity receptor for activin, type II activin receptor (ActRIIA), by administration of the soluble extracellular domain of ActRIIA fused to a murine IgG2a-Fc, increases bone formation, bone mass, and bone strength in normal mice and in ovariectomized mice with established bone loss. These observations support the development of this pharmacological strategy for the treatment of diseases with skeletal fragility.
Assuntos
Receptores de Activinas Tipo II/farmacologia , Osso e Ossos/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Receptores de Activinas Tipo II/administração & dosagem , Receptores de Activinas Tipo II/isolamento & purificação , Animais , Fenômenos Biomecânicos , Reabsorção Óssea , Linhagem Celular , Feminino , Humanos , Imunoglobulina G/administração & dosagem , Imunoglobulina G/isolamento & purificação , Imunoglobulina G/farmacologia , Vértebras Lombares/efeitos dos fármacos , Camundongos , Tamanho do Órgão/efeitos dos fármacos , Ovariectomia , Proteínas Recombinantes de Fusão/administração & dosagem , Proteínas Recombinantes de Fusão/isolamento & purificação , Proteínas Recombinantes de Fusão/farmacologia , Solubilidade/efeitos dos fármacosRESUMO
Hemizygous Lis1 mutations cause type 1 lissencephaly, a neuronal migration disorder in humans. The Lis1+/- mouse is a model for lissencephaly; mice exhibit neuronal migration defects but are viable and fertile. On an inbred genetic background, 20% of Lis1+/- mice develop hydrocephalus and die prematurely. Lis1 functions with the microtubule motor cytoplasmic dynein. Because dynactin, a dynein regulator, interacts with end-binding protein 1 (EB1) and beta-catenin, two known binding partners of the adenomatous polyposis coli (APC) protein, we looked for a genetic interaction between Lis1 and APC. Mice with a heterozygous truncating mutation in APC (Min mutation) do not exhibit neuronal migration defects or develop hydrocephalus. However, the presence of the APC mutation increases the migration deficit and the incidence of hydrocephalus in Lis1+/- animals. Lis1 and dynein distribution is altered in cells derived from Min mice, and both Lis1 and dynein interact with the C terminus of APC in vitro. Together, our findings point to a previously unknown interaction between APC and Lis1 during mammalian brain development.