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BACKGROUND: Although many molecules have been investigated as biomarkers for spinal cord injury (SCI) or ischemic stroke, none of them are specifically induced in central nervous system (CNS) neurons following injuries with low baseline expression. However, neuronal injury constitutes a major pathology associated with SCI or stroke and strongly correlates with neurological outcomes. Biomarkers characterized by low baseline expression and specific induction in neurons post-injury are likely to better correlate with injury severity and recovery, demonstrating higher sensitivity and specificity for CNS injuries compared to non-neuronal markers or pan-neuronal markers with constitutive expressions. METHODS: In animal studies, young adult wildtype and global Atf3 knockout mice underwent unilateral cervical 5 (C5) SCI or permanent distal middle cerebral artery occlusion (pMCAO). Gene expression was assessed using RNA-sequencing and qRT-PCR, while protein expression was detected through immunostaining. Serum ATF3 levels in animal models and clinical human samples were measured using commercially available enzyme-linked immune-sorbent assay (ELISA) kits. RESULTS: Activating transcription factor 3 (ATF3), a molecular marker for injured dorsal root ganglion sensory neurons in the peripheral nervous system, was not expressed in spinal cord or cortex of naïve mice but was induced specifically in neurons of the spinal cord or cortex within 1 day after SCI or ischemic stroke, respectively. Additionally, ATF3 protein levels in mouse blood significantly increased 1 day after SCI or ischemic stroke. Importantly, ATF3 protein levels in human serum were elevated in clinical patients within 24 hours after SCI or ischemic stroke. Moreover, Atf3 knockout mice, compared to the wildtype mice, exhibited worse neurological outcomes and larger damage regions after SCI or ischemic stroke, indicating that ATF3 has a neuroprotective function. CONCLUSIONS: ATF3 is an easily measurable, neuron-specific biomarker for clinical SCI and ischemic stroke, with neuroprotective properties. HIGHLIGHTS: ATF3 was induced specifically in neurons of the spinal cord or cortex within 1 day after SCI or ischemic stroke, respectively. Serum ATF3 protein levels are elevated in clinical patients within 24 hours after SCI or ischemic stroke. ATF3 exhibits neuroprotective properties, as evidenced by the worse neurological outcomes and larger damage regions observed in Atf3 knockout mice compared to wildtype mice following SCI or ischemic stroke.

Inhibitors of VEGF signaling can block angiogenesis and reduce tumor vascularity, but little is known about the reversibility of these changes after treatment ends. In the present study, regrowth of [...]

The molecular diversity of receptors in human blood vessels remains largely unexplored. We developed a selection method in which peptides that home to specific vascular beds are identified after administration of a peptide library. Here we report the first in vivo screening of a peptide library in a patient. We surveyed 47,160 motifs that localized to different organs. This large-scale screening indicates that the tissue distribution of circulating peptides is nonrandom. High-throughput analysis of the motifs revealed similarities to ligands for differentially expressed cell-surface proteins, and a candidate ligand-receptor pair was validated. These data represent a step toward the construction of a molecular map of human vasculature and may have broad implications for the development of targeted therapies., Author(s): Wadih Arap (corresponding author) [1, 2]; Mikhail G. Kolonin [1, 11]; Martin Trepel [1, 11]; Johanna Lahdenranta [1]; Marina Cardo-Vila [1]; Ricardo J. Giordano [1]; Paul J. Mintz [1]; [...]

The introduction of ISH2, a 52Obp transposable element, into the coding region of the SR-I apoprotein gene sopI causes the SR-I- Htr- phenotype in Halobacterium salinarium. The Halobacterium consists of a phototaxis-deficient mutant which does not have the sensory rhodopsin I (SR-I) and the putative transducer protein HtrI of SR-I. The removal of the 11 kbp upstream of ISH2 also contributes to the occurrence of the phenotype.

Abstract Background One mechanism that directs the action of the second messengers, cAMP and diacylglycerol, is the compartmentalization of protein kinase A (PKA) and protein kinase C (PKC). A-kinase anchoring proteins (AKAPs) can recruit both enzymes to specific subcellular locations via interactions with the various isoforms of each family of kinases. We found previously that a new class of AKAPs, dual-specific AKAPs, denoted D-AKAP1 and D-AKAP2, bind to RIα in addition to the RII subunits. Results Immunohistochemistry and confocal microscopy were used here to determine that D-AKAP1 colocalizes with RIα at the postsynaptic membrane of the vertebrate neuromuscular junction (NMJ) and the adjacent muscle, but not in the presynaptic region. The labeling pattern for RIα and D-AKAP1 overlapped with mitochondrial staining in the muscle fibers, consistent with our previous work showing D-AKAP1 association with mitochondria in cultured cells. The immunoreactivity of D-AKAP2 was distinct from that of D-AKAP1. We also report here that even though the PKA type II subunits (RIIα and RIIβ) are localized at the NMJ, their patterns are distinctive and differ from the other R and D-AKAP patterns examined. PKCβ appeared to colocalize with the AKAP, gravin, at the postsynaptic membrane. Conclusions The kinases and AKAPs investigated have distinct patterns of colocalization, which suggest a complex arrangement of signaling micro-environments. Because the labeling patterns for RIα and D-AKAP 1 are similar in the muscle fibers and at the postsynaptic membrane, it may be that this AKAP anchors RIα in these regions. Likewise, gravin may be an anchor of PKCβ at the NMJ.

Background: One mechanism that directs the action of the second messengers, cAMP and diacylglycerol, is the compartmentalization of protein kinase A (PKA) and protein kinase C (PKC). A-kinase anchoring proteins (AKAPs) can recruit both enzymes to specific subcellular locations via interactions with the various isoforms of each family of kinases. We found previously that a new class of AKAPs, dual-specific AKAPs, denoted D-AKAP1 and D-AKAP2, bind to RIalpha in addition to the RII subunits.Results: Immunohistochemistry and confocal microscopy were used here to determine that D-AKAP1 colocalizes with RIalpha at the postsynaptic membrane of the vertebrate neuromuscular junction (NMJ) and the adjacent muscle, but not in the presynaptic region. The labeling pattern for RIalpha and D-AKAP1 overlapped with mitochondrial staining in the muscle fibers, consistent with our previous work showing D-AKAP1 association with mitochondria in cultured cells. The immunoreactivity of D-AKAP2 was distinct from that of D-AKAP1. We also report here that even though the PKA type II subunits (RIIalpha and RIIbeta) are localized at the NMJ, their patterns are distinctive and differ from the other R and D-AKAP patterns examined. PKCbeta appeared to colocalize with the AKAP, gravin, at the postsynaptic membrane.Conclusions: The kinases and AKAPs investigated have distinct patterns of colocalization, which suggest a complex arrangement of signaling micro-environments. Because the labeling patterns for RIalpha and D-AKAP 1 are similar in the muscle fibers and at the postsynaptic membrane, it may be that this AKAP anchors RIalpha in these regions. Likewise, gravin may be an anchor of PKCbeta at the NMJ. [ABSTRACT FROM AUTHOR]

Glucose-regulated protein 78 (GRP78) is a potential receptor for targeting therapy in cancer and chronic vascular disease due to its overexpression at the cell surface in tumor cells and in atherosclerotic lesions. Presence of the GRP78 autoantibody in cancer patient sera is generally associated with poor prognosis since it signals a prosurvival mechanism in response to cellular stress. Association of GRP78 with various binding partners involves coordination of multiple signaling pathways that result in either cell survival or cell death. Binding of activated alpha2-macroglobulin to cell-surface GRP78 activates Akt to suppress apoptotic pathways through multiple downstream effectors, and concomitantly upregulates NF-kappaBeta and induces the unfolded protein response (UPR) so that cell proliferation prevails. Interaction of GRP78 with cell-surface T-cadherin promotes endothelial cell survival. Association of oncogenic Cripto with GRP78 nullifies TGF-beta superfamily-dependent signaling through Smad2/3 to promote cell proliferation. In contrast, association of GRP78 with the plasminogen kringle 5 domain or extracellular Par-4 promotes apoptosis. Interaction of GRP78 with microplasminogen induces the UPR while association with tissue factor inhibits procoagulant activity. The diverse and multiple binding proteins of GRP78 and their equally diverse functional outcomes reflect the regulatory cellular functions that GRP78 orchestrates. Several GRP78 targeting peptides have been isolated from different tumors and they show remarkable tumor specificity. Conjugation of GRP78-targeting peptides to an apoptosis-inducing peptide suppresses tumor growth in tumor xenografts, thereby demonstrating that GRP78 is a viable target by which clinical cancer therapies can be successfully developed as well as its potential utility in treating vascular disease., (Copyright (c) 2010 Elsevier Inc. All rights reserved.)