Detection of TTR Amyloid in the Conjunctiva Using a Novel Fluorescent Ocular Tracer.

Background: Transthyretin amyloidosis (ATTR) is a significant cause of cardiomyopathy and other morbidities in the elderly and Black Americans. ATTR can be treated with new disease-modifying therapies, but large shortfalls exist in its diagnosis. The objective of this study was to test whether TTR amyloid can be detected and imaged in the conjunctiva using a novel small-molecule fluorescent ocular tracer, with the implication that ATTR might be diagnosable by a simple eye examination.

Novel regenerative drug, SPG302 promotes functional recovery of diaphragm muscle activity after cervical spinal cord injury.

Spinal cord hemisection at C (C SH), sparing the dorsal column is widely used to investigate the effects of reduced phrenic motor neuron (PhMN) activation on diaphragm muscle (DIAm) function, with reduced DIAm activity on the injured side during eupnoea. Following C SH, recovery of DIAm EMG activity may occur spontaneously over subsequent days/weeks. Various strategies have been effective at improving the incidence and magnitude of DIAm recovery during eupnoea, but little is known about the effects of C SH on transdiaphragmatic pressure (P ) during other ventilatory and non-ventilatory behaviours.

The transcript interactome of skeletal muscle RNA binding protein motif 3 (RBM3).

Post-transcriptional regulation of gene expression represents a critical regulatory step in the production of a functional proteome. Elevated expression of post-transcriptional regulator RNA binding motif protein 3 (RBM3), an RNA binding protein in the cold-shock family, is positively correlated with skeletal muscle growth in adult mice. However, mechanisms through which RBM3 exerts its effects are largely unknown.

SPG302 Reverses Synaptic and Cognitive Deficits Without Altering Amyloid or Tau Pathology in a Transgenic Model of Alzheimer's Disease.

Alzheimer's disease (AD) is conceptualized as a synaptic failure disorder in which loss of glutamatergic synapses is a major driver of cognitive decline. Thus, novel therapeutic strategies aimed at regenerating synapses may represent a promising approach to mitigate cognitive deficits in AD patients. At present, no disease-modifying drugs exist for AD, and approved therapies are palliative at best, lacking in the ability to reverse the synaptic failure.

Skeletal muscle RBM3 expression is associated with extended lifespan in Ames Dwarf and calorie restricted mice.

RNA binding protein motif 3 (RBM3) is an RNA-binding and cold shock protein that protects myoblasts and promotes skeletal muscle hypertrophy by enhancing mRNA stability and translation. Muscle size is decreased during aging; however, it is typically delayed in models of extended lifespan such as the long-lived Ames Dwarf (df/df) mice and calorie restricted (CR) animals compared to age-matched controls. In light of the protective and anabolic effects of RBM3 in muscle, we hypothesized that RBM3 expression is higher in long-lived animal models.

HAP1 is an in vivo UBE3A target that augments autophagy in a mouse model of Angelman syndrome.

Angelman syndrome (AS) is a severe neurodevelopmental disorder caused by maternal mutation and paternal imprinting of the gene encoding UBE3A, an E3 ubiquitin ligase. Although several potential target proteins of UBE3A have been reported, how these proteins regulate neuronal development remains unclear. We performed a large-scale quantitative proteomic analysis using stable-isotope labeling of amino acids in mammals (SILAM) in mice with maternal Ube3a mutation.

Synaptic actin stabilization protein loss in Down syndrome and Alzheimer disease.

Reduced spine densities and age-dependent accumulation of amyloid β and tau pathology are shared features of Down syndrome (DS) and Alzheimer's disease (AD). Both spine morphology and the synaptic plasticity that supports learning depend upon the actin cytoskeleton, suggesting that disturbances in actin regulatory signaling might underlie spine defects in both disorders. The present study evaluated the synaptic levels of two proteins that promote filamentous actin stabilization, the Rho GTPase effector p21-activated kinase 3 (PAK3) and Arp2, in DS vs.

RNA-binding proteins: The next step in translating skeletal muscle adaptations?

The decline of skeletal muscle mass during illness, injury, disuse, and aging is associated with poor health outcomes. Therefore, it is important to pursue a greater understanding of the mechanisms that dictate skeletal muscle adaptation. In this review, we propose that RNA-binding proteins (RBPs) comprise a critical regulatory node in the orchestration of adaptive responses in skeletal muscle.

Cold shock protein RBM3 attenuates atrophy and induces hypertrophy in skeletal muscle.

RNA-binding motif protein 3 (RBM3), a stress-inducible RNA-binding protein that increases protein synthesis and confers cell protection in multiple cell types, has been identified as a possible regulator of skeletal muscle mass. Therefore, the primary aim of this study was to examine the impact of elevated RBM3 on skeletal muscle hypertrophy and resistance to atrophy. Plasmid-mediated overexpression of RBM3 in vitro and in vivo was used to assess the role of RBM3 in muscle.

Morphoregulatory functions of the RNA-binding motif protein 3 in cell spreading, polarity and migration.

RNA-binding proteins are emerging as key regulators of transitions in cell morphology. The RNA-binding motif protein 3 (RBM3) is a cold-inducible RNA-binding protein with broadly relevant roles in cellular protection, and putative functions in cancer and development. Several findings suggest that RBM3 has morphoregulatory functions germane to its roles in these contexts.

A heterogeneous tRNA granule structure exhibiting rapid, bi-directional neuritic transport.

mRNA translation is regulated by diverse mechanisms that converge at the initiation and elongation steps to determine the rate, profile, and localization of proteins synthesized. A consistently relevant feature of these mechanisms is the spatial re-distribution of translation machinery, a process of particular importance in neural cells. This process has, however, been largely overlooked with respect to its potential role in regulating the local concentration of cytoplasmic tRNAs, even as a multitude of data suggest that spatial regulation of the tRNA pool may help explain the remarkably high rates of peptide elongation.

Fmr1 deficiency promotes age-dependent alterations in the cortical synaptic proteome.

Fragile X syndrome (FXS) is an X-linked neurodevelopmental disorder characterized by severe intellectual disability and other symptoms including autism. Although caused by the silencing of a single gene, Fmr1 (fragile X mental retardation 1), the complexity of FXS pathogenesis is amplified because the encoded protein, FMRP, regulates the activity-dependent translation of numerous mRNAs. Although the mRNAs that associate with FMRP have been extensively studied, little is known regarding the proteins whose expression levels are altered, directly or indirectly, by loss of FMRP during brain development.

Reversal of disease-related pathologies in the fragile X mouse model by selective activation of GABAB receptors with arbaclofen.

Fragile X syndrome (FXS), the most common inherited cause of intellectual disability and autism, results from the transcriptional silencing of FMR1 and loss of the mRNA translational repressor protein fragile X mental retardation protein (FMRP). Patients with FXS exhibit changes in neuronal dendritic spine morphology, a pathology associated with altered synaptic function. Studies in the mouse model of fragile X have shown that loss of FMRP causes excessive synaptic protein synthesis, which results in synaptic dysfunction and altered spine morphology.

Widespread regulation of miRNA biogenesis at the Dicer step by the cold-inducible RNA-binding protein, RBM3.

MicroRNAs (miRNAs) play critical roles in diverse cellular events through their effects on translation. Emerging data suggest that modulation of miRNA biogenesis at post-transcriptional steps by RNA-binding proteins is a key point of regulatory control over the expression of some miRNAs and the cellular processes they influence. However, the extent and conditions under which the miRNA pathway is amenable to regulation at posttranscriptional steps are poorly understood.

15N-labeled brain enables quantification of proteome and phosphoproteome in cultured primary neurons.

Terminally differentiated primary cells represent a valuable in vitro model to study signaling events associated within a specific tissue. Quantitative proteomic methods using metabolic labeling in primary cells encounter labeling efficiency issues hindering the use of these cells. Here we developed a method to quantify the proteome and phosphoproteome of cultured neurons using (15)N-labeled brain tissue as an internal standard and applied this method to determine how an inhibitor of an excitatory neural transmitter receptor, phencyclidine (PCP), affects the global phosphoproteome of cortical neurons.

Enhanced survival of skeletal muscle myoblasts in response to overexpression of cold shock protein RBM3.

Cold-inducible RNA-binding protein (RBM3) is suggested to be involved in the regulation of skeletal muscle mass. Cell death pathways are implicated in the loss of muscle mass and therefore the role of RBM3 in muscle apoptosis in C(2)C(12) myoblasts was investigated in this study. RBM3 overexpression was induced by either cold shock (32°C exposure for 6 h) or transient transfection with a myc-tagged RBM3 expression vector.

Developmentally regulated expression of the cold-inducible RNA-binding motif protein 3 in euthermic rat brain.

mRNA-binding proteins are critical regulators of protein synthesis during neural development. We demonstrated previously that the cold-inducible mRNA-binding protein 3 (RBM3) is present within euthermic neurons and that it enhances translation. Other studies have attributed anti-apoptotic and proliferative functions to RBM3.

Quantitative proteomic analysis of primary neurons reveals diverse changes in synaptic protein content in fmr1 knockout mice.

Fragile X syndrome (FXS) is a common inherited form of mental retardation that is caused, in the vast majority of cases, by the transcriptional silencing of a single gene, fmr1. The encoded protein, FMRP, regulates mRNA translation in neuronal dendrites, and it is thought that changes in translation-dependent forms of synaptic plasticity lead to many symptoms of FXS. However, little is known about the potentially extensive changes in synaptic protein content that accompany loss of FMRP.

Two isoforms of the cold-inducible mRNA-binding protein RBM3 localize to dendrites and promote translation.

A diverse set of mRNA-binding proteins (BPs) regulate local translation in neurons. However, little is known about the role(s) played by a family of cold-inducible, glycine-rich mRNA-BPs. Unlike neuronal mRNA-BPs characterized thus far, these proteins are induced by hypothermia and are comprised of one RNA recognition motif and an adjacent arginine- and glycine-rich domain.

BDNF induces widespread changes in synaptic protein content and up-regulates components of the translation machinery: an analysis using high-throughput proteomics.

The brain-derived neurotrophic factor (BDNF) plays an important role in neuronal development, and in the formation and plasticity of synaptic connections. These effects of BDNF are at least partially due to the ability of the neurotrophin to increase protein synthesis both globally and locally. However, only a few proteins have been shown to be up-regulated at the synapse by BDNF.

Early postnatal plasticity in neocortex of Fmr1 knockout mice.

Fragile X syndrome is produced by a defect in a single X-linked gene, called Fmr1, and is characterized by abnormal dendritic spine morphologies with spines that are longer and thinner in neocortex than those from age-matched controls. Studies using Fmr1 knockout mice indicate that spine abnormalities are especially pronounced in the first month of life, suggesting that altered developmental plasticity underlies some of the behavioral phenotypes associated with the syndrome. To address this issue, we used intracellular recordings in neocortical slices from early postnatal mice to examine the effects of Fmr1 disruption on two forms of plasticity active during development.

Differential translation and fragile X syndrome.

Fragile X syndrome (FXS) is caused by the transcriptional silencing of the Fmr1 gene, which encodes a protein (FMRP) that can act as a translational suppressor in dendrites, and is characterized by a preponderance of abnormally long, thin and tortuous dendritic spines. According to a current theory of FXS, the loss of FMRP expression leads to an exaggeration of translation responses linked to group I metabotropic glutamate receptors. Such responses are involved in the consolidation of a form of long-term depression that is enhanced in Fmr1 knockout mice and in the elongation of dendritic spines, resembling synaptic phenotypes over-represented in fragile X brain.

Cold stress-induced protein Rbm3 binds 60S ribosomal subunits, alters microRNA levels, and enhances global protein synthesis.

The expression of Rbm3, a glycine-rich RNA-binding protein, is enhanced under conditions of mild hypothermia, and Rbm3 has been postulated to facilitate protein synthesis at colder temperatures. To investigate this possibility, Rbm3 was overexpressed as a c-Myc fusion protein in mouse neuroblastoma N2a cells. Cells expressing this fusion protein showed a 3-fold increase in protein synthesis at both 37 degrees C and 32 degrees C compared with control cells.