Clinical Utility of Tumor-Naïve Pre-surgical ctDNA Detection in Early-stage NSCLC.

PURPOSE: The use of tumor-informed circulating tumor DNA (ctDNA) testing in early-stage patients before surgery is limited mainly due to restricted tissue access and extended turnaround times. This study aimed to evaluate the clinical value of a tumor-naïve, methylation-based cell-free DNA assay in a large cohort of patients with resected non-small cell lung cancer (NSCLC). METHOD: We analyzed pre-surgical plasma samples from 895 patients with EGFR and ALK-wild-type, clinical stage I or II NSCLC. The ctDNA status was evaluated for its prognostic significance in relation to tumor volume, metabolic activity, histology, histological subtypes, and clinical-to-pathological TNM upstaging. RESULTS: Pre-surgical ctDNA detection was observed in 55 out of 414 (13%) patients with clinical stage I lung adenocarcinoma (LUAD) and was associated with poor recurrence-free survival (RFS) (2-year RFS 69% versus 91%; log-rank P<0.001), approaching that of clinical stage II LUAD. Pre-surgical ctDNA detection was not prognostic in patients with clinical stage II LUAD or non-LUAD. Within LUAD, tumor volume and positron emission tomography avidity interacted to predict pre-surgical ctDNA detection. Moreover, pre-surgical ctDNA detection was predictive of the post-surgical discovery of IASLC G3 tumors (P<0.001) and pathological TNM upstaging (P<0.001). Notably, pre-surgical ctDNA detection strongly correlated with higher PD-L1 expression in tumors (positive rates 28% vs. 55%, P<0.001), identifying a subgroup likely to benefit from anti-PD-(L)-1 therapies. CONCLUSION: These findings support the integration of ctDNA testing into routine diagnostic workflows in early-stage NSCLC without the need of tumor tissue profiling. Furthermore, it is clinically useful in identifying high-risk patients who might benefit from innovative treatments, including neoadjuvant immune checkpoint inhibitors.

Impact of clinical supervision on the mental health nursing workforce: a scoping review protocol.

INTRODUCTION: Mental health nurses work in potentially unpredictable, stressful and complex environments that can lead to burn-out and high staff turnover. Clinical supervision is a formal and professional agreement between two or more people that aims to strengthen individuals' competencies and organisational strengths. Effective clinical supervision has been noted as a method of reducing workplace issues within mental health nursing, but there is not currently a synthesis of evidence in this area. The key objective of this scoping review is to identify, map and analyse the available evidence reporting on the impact of clinical supervision on workforce outcomes for mental health nurses. METHODS: A scoping review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses-Scoping Review Extension method will be conducted exploring clinical supervision for mental health nurses. A search for academic literature from Medline, CINAHL, Embase and PsycINFO will be combined with grey literature sourced through Google to identify potentially relevant studies. Studies identified by the search strategy will be managed using Covidence, and two authors will screen all identified articles. Reference lists of included studies will be handsearched to identify any potentially relevant studies missed by the search strategy. ANALYSIS: A summary tool including predefined categories (such as author, date published, workforce outcome measured) will be used to summarise the included studies in this scoping review. Additionally, a narrative synthesis approach will be used to report the outcomes of included studies and provide further analysis. ETHICS AND DISSEMINATION: This scoping review protocol described research that will use secondary analysis of publicly available information, and therefore, does not require ethics approval. The findings of this research will be disseminated through publication in a peer-reviewed academic journal and relevant conference presentations.

The Effectiveness of the Safety Planning Intervention for Adults Experiencing Suicide-Related Distress: A Systematic Review.

The safety planning intervention (SPI) is gaining momentum in suicide prevention practice and research. This systematic review sought to determine the effectiveness of the SPI for adults experiencing suicide-related distress. Systematic searches of international, peer-reviewed literature were conducted in six databases (Cochrane Trials, Embase, Emcare, Medline, PsycINFO and Web of Science), including terms for safety planning, suicide, and suicide-related outcomes. A total of 565 results were included for screening. Result screening (title/abstract and full-text), data extraction and critical appraisal were conducted in duplicate. Twenty-six studies met the inclusion criteria. Studies were primarily quantitative (n = 20), largely with general adult or veteran samples; a small number of studies explored the perspectives of staff and significant others. Half of the studies included the SPI as a standalone intervention, while the other half examined the SPI in combination with other interventions. Most interventions were delivered in-person, with a hard-copy safety plan created, while a smaller number explored internet-based interventions. Primary measures included: suicidality (ideation, behavior, deaths; 10 studies), suicide-related outcomes (depression, hopelessness; 5 studies) and treatment outcomes (hospitalizations, treatment engagement; 7 studies). The evidence supports improvements in each of these domains, with complementary findings from the remaining quantitative and qualitative studies suggesting that the SPI is a feasible and acceptable intervention. While positive, these findings are limited by the heterogeneity of interventions and study designs, making the specific impact of the SPI difficult to both determine and generalize. Conversely, this also points to the flexibility of the SPI.HighlightsThe Safety Planning Intervention (SPI) is a valuable indicated intervention for general adult and veteran populations experiencing suicide-related distress, primarily in face-to-face, clinical settings.Quantitative findings indicate associations between the SPI and improvements in suicidal ideation and behavior, decreases in depression and hopelessness, along with reductions in hospitalizations and improvements in treatment attendance.Qualitative studies suggest the SPI is acceptable and feasible, with areas for development.SPIs have been shown to be adaptable to the clinical area in its modality (digital or paper-based), delivery (face-to-face or online), facilitation (clinician or self-administered) and multiplicity (as stand-alone or combined intervention).

The impact of suicide prevention education programmes for nursing students: A systematic review.

The purpose of this systematic review was to locate and synthesize peer-reviewed evidence regarding the effectiveness of providing suicide prevention education to nursing students. Systematic searches were conducted in seven databases (EMBASE, EmCare, Joanna Briggs, MEDLINE, PsycINFO, Scopus, and Web of Science). Results were screened in duplicate at two stages: title and abstract, and full text. Critical appraisal and data extraction were also completed in duplicate. Initial database searching yielded 303 results. Following the addition of seven records from relevant reference lists, and the removal of duplicates, a total of 118 results were included for screening. Eight articles were deemed eligible for inclusion in this review; most (n = 5) were quantitative. While all were conducted within university settings, half were stand-alone education sessions, while the remaining were integrated with existing programmes/courses. The types of education programmes varied considerably across studies, with only three being established, evidence-based programmes. The studies explore a range of outcomes, which have been narratively categorized as enhanced skills, abilities, and self-confidence; development of positive attitudes and beliefs; acquisition of knowledge; and programme experience and evaluation. While there is a small body of evidence indicating that suicide prevention education programmes contribute to improvements in skills, abilities, self-confidence, and attitudes among nursing students, the variability in educational interventions and outcomes, coupled with short-term evaluation time frames, makes it difficult to fully understand the impact of this important suicide prevention strategy.

Acute Effect of Oral N-Acetylcysteine on Muscle Soreness and Exercise Performance in Semi-Elite Rugby Players.

N-acetylcysteine (NAC) supplementation may enhance performance and reduce soreness from acute, repeated-sprint, high-intensity exercise. Our aim was to investigate whether semi-elite rugby union athletes may benefit. In a randomized block design, 17 semi-elite male rugby players were assigned to receive either 1 g oral NAC (n = 8) or placebo (n = 9) for six days. The mean percentage effect of NAC on exercise performance was assessed through completion of a broken bronco exercise test on days 5 and 6 of supplementation. Players self-reported muscle soreness and tolerability to supplements using a modified Muscle Pain and Treatment Satisfaction Questionnaire throughout the supplement duration. NAC produced a likely beneficial performance effect on maximum shuttle sprint time (2.4%; 90% confidence limit ± 4.8%) but was unclear on total time during back-to-back broken bronco tests compared to placebo. NAC had a likely protective effect on subjective muscle soreness during days 1-4 of supplementation (-19% ± 27%) but a very likely harmful effect on days 5 and 6 of supplementation (71% ± 59%). Daily supplementation with 1 g of oral NAC for six days produced no adverse side effects, reduced muscle soreness after one bout of damaging exercise, but increased soreness following the second bout. The performance effects were generally unclear apart from maximal sprint time.

Performance and Side Effects of Supplementation with N-Acetylcysteine: A Systematic Review and Meta-Analysis.

BACKGROUND: N-Acetylcysteine (NAC) is a promising antioxidant supplement with potential as an acute strategy to enhance performance in elite sport, but there are concerns about its side effects with high doses. OBJECTIVE: To review the current literature and evaluate the effects of NAC supplementation on sport performance and the risk of adverse effects. METHODS: The literature up to May 2016 was searched on MEDLINE (PubMed), EMBASE, SPORTDiscus, Google Scholar and Scopus databases to identify all studies investigating the effects of NAC supplementation on exercise performance and/or side effects experienced. Performance outcomes from each study were converted to the percent effect equivalent to mean power output in a time trial. All pooled analyses were based on random-effects models generated by Review Manager (RevMan) [Computer program], version 5.3 (The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen, 2014). RESULTS: A total of seven studies met criteria for inclusion in the sport performance meta-analysis, and 17 for inclusion in the side effects meta-analysis. The typical daily dose of NAC reported was 5.8 g·d-1; with a range between 1.2 and 20.0 g·d-1. The mean increase in performance was 0.29% (95% confidence interval -0.67 to 1.25). The difference in the odds ratio of side effects on NAC compared with placebo was 1.11 (95% confidence interval 0.88-1.39). The sub-analysis of NAC dose suggested an increase in side effects as the dosage of NAC increased; however, this observation requires further investigation. CONCLUSIONS: Despite initial research publications reporting positive performance effects with NAC, at this stage it cannot be recommended further. The risk of side effects from NAC supplementation also remains unclear owing to significant variations in effects. Suboptimal reporting and documentation in the literature creates difficulties when meta-analysing outcomes and generating conclusions.

Intergenerational transmission of dietary behaviours: A qualitative study of Anglo-Australian, Chinese-Australian and Italian-Australian three-generation families.

Family food choice is complex with a number of people within the family sharing food choice and preparation responsibilities. Differences in dietary behaviours also exist between various ethnic groups worldwide, and are apparent within multicultural nations such as Australia. This study examined the intergenerational transmission of eating behaviour through semi-structured family interviews with 27 three generation families (Anglo-Australian: n = 11, Chinese-Australian: n = 8, Italian-Australian: n = 8; N = 114). The influence of generation (grandparent, parent, child), role (grandmother, grandfather, mother, father, daughter, son), and ethnic background were considered. Thematic analysis identified that regardless of ethnic background, grandmothers and mothers dominated family food choice decisions even in families where fathers were primarily responsible for the preparation of family meals. The women in each generation influenced fruit and vegetable intake by controlling purchasing decisions (e.g., by shopping for food or editing family grocery shopping lists), insisting on consumption, monitoring and reminding, utilizing food as a prerequisite for conditional treats (e.g., eating fruit before being allowed snacks), instigating and enforcing food rules (e.g., fast food only on weekends), and restricting others' food choices. Grandparents and children shared a relationship that skipped the parent generation and influenced dietary behaviours bi-directionally. These findings have implications for the delivery of dietary health messages used in disease prevention interventions designed to successfully reach culturally and linguistically diverse populations and all members of multigenerational families.

Rapid outbreak sequencing of Ebola virus in Sierra Leone identifies transmission chains linked to sporadic cases.

To end the largest known outbreak of Ebola virus disease (EVD) in West Africa and to prevent new transmissions, rapid epidemiological tracing of cases and contacts was required. The ability to quickly identify unknown sources and chains of transmission is key to ending the EVD epidemic and of even greater importance in the context of recent reports of Ebola virus (EBOV) persistence in survivors. Phylogenetic analysis of complete EBOV genomes can provide important information on the source of any new infection. A local deep sequencing facility was established at the Mateneh Ebola Treatment Centre in central Sierra Leone. The facility included all wetlab and computational resources to rapidly process EBOV diagnostic samples into full genome sequences. We produced 554 EBOV genomes from EVD cases across Sierra Leone. These genomes provided a detailed description of EBOV evolution and facilitated phylogenetic tracking of new EVD cases. Importantly, we show that linked genomic and epidemiological data can not only support contact tracing but also identify unconventional transmission chains involving body fluids, including semen. Rapid EBOV genome sequencing, when linked to epidemiological information and a comprehensive database of virus sequences across the outbreak, provided a powerful tool for public health epidemic control efforts.

Development and validation of a scalable next-generation sequencing system for assessing relevant somatic variants in solid tumors.

Next-generation sequencing (NGS) has enabled genome-wide personalized oncology efforts at centers and companies with the specialty expertise and infrastructure required to identify and prioritize actionable variants. Such approaches are not scalable, preventing widespread adoption. Likewise, most targeted NGS approaches fail to assess key relevant genomic alteration classes. To address these challenges, we predefined the catalog of relevant solid tumor somatic genome variants (gain-of-function or loss-of-function mutations, high-level copy number alterations, and gene fusions) through comprehensive bioinformatics analysis of >700,000 samples. To detect these variants, we developed the Oncomine Comprehensive Panel (OCP), an integrative NGS-based assay [compatible with <20 ng of DNA/RNA from formalin-fixed paraffin-embedded (FFPE) tissues], coupled with an informatics pipeline to specifically identify relevant predefined variants and created a knowledge base of related potential treatments, current practice guidelines, and open clinical trials. We validated OCP using molecular standards and more than 300 FFPE tumor samples, achieving >95% accuracy for KRAS, epidermal growth factor receptor, and BRAF mutation detection as well as for ALK and TMPRSS2:ERG gene fusions. Associating positive variants with potential targeted treatments demonstrated that 6% to 42% of profiled samples (depending on cancer type) harbored alterations beyond routine molecular testing that were associated with approved or guideline-referenced therapies. As a translational research tool, OCP identified adaptive CTNNB1 amplifications/mutations in treated prostate cancers. Through predefining somatic variants in solid tumors and compiling associated potential treatment strategies, OCP represents a simplified, broadly applicable targeted NGS system with the potential to advance precision oncology efforts.

Next-Gen Sequencing Exposes Frequent MED12 Mutations and Actionable Therapeutic Targets in Phyllodes Tumors.

UNLABELLED: Phyllodes tumors are rare fibroepithelial tumors with variable clinical behavior accounting for a small subset of all breast neoplasms, yet little is known about the genetic alterations that drive tumor initiation and/or progression. Here, targeted next-generation sequencing (NGS) was used to identify somatic alterations in formalin-fixed paraffin-embedded (FFPE) patient specimens from malignant, borderline, and benign cases. NGS revealed mutations in mediator complex subunit 12 (MED12) affecting the G44 hotspot residue in the majority (67%) of cases spanning all three histologic grades. In addition, loss-of-function mutations in p53 (TP53) as well as deleterious mutations in the tumor suppressors retinoblastoma (RB1) and neurofibromin 1 (NF1) were identified exclusively in malignant tumors. High-level copy-number alterations (CNA) were nearly exclusively confined to malignant tumors, including potentially clinically actionable gene amplifications in IGF1R and EGFR. Taken together, this study defines the genomic landscape underlying phyllodes tumor development, suggests potential molecular correlates to histologic grade, expands the spectrum of human tumors with frequent recurrent MED12 mutations, and identifies IGF1R and EGFR as potential therapeutic targets in malignant cases. IMPLICATIONS: Integrated genomic sequencing and mutational profiling provides insight into the molecular origin of phyllodes tumors and indicates potential druggable targets in malignant disease. Visual Overview: http://mcr.aacrjournals.org/content/early/2015/04/02/1541-7786.MCR-14-0578/F1.large.jpg.

Distribution and synthesis of extracellular matrix proteoglycans, hyaluronan, link proteins and tenascin-R in the rat spinal cord.

Perineuronal nets (PNNs) are dense extracellular matrix (ECM) structures that form around many neuronal cell bodies and dendrites late in development. They contain several chondroitin sulphate proteoglycans (CSPGs), hyaluronan, link proteins and tenascin-R. Their time of appearance correlates with the ending of the critical period for plasticity, and they have been implicated in this process. The distribution of PNNs in the spinal cord was examined using Wisteria floribunda agglutinin lectin and staining for chondroitin sulphate stubs after chondroitinase digestion. Double labelling with the neuronal marker, NeuN, showed that PNNs were present surrounding approximately 30% of motoneurons in the ventral horn, 50% of large interneurons in the intermediate grey and 20% of neurons in the dorsal horn. These PNNs formed in the second week of postnatal development. Immunohistochemical staining demonstrated that the PNNs contain a mixture of CSPGs, hyaluronan, link proteins and tenascin-R. Of the CSPGs, aggrecan was present in all PNNs while neurocan, versican and phosphacan/RPTPbeta were present in some but not all PNNs. In situ hybridization showed that aggrecan and cartilage link protein (CRTL 1) and brain link protein-2 (BRAL 2) are produced by neurons. PNN-bearing neurons express hyaluronan synthase, and this enzyme and phosphacan/RPTPbeta may attach PNNs to the cell surface. During postnatal development the expression of link protein and aggrecan mRNA is up-regulated at the time of PNN formation, and these molecules may therefore trigger their formation.

How does chondroitinase promote functional recovery in the damaged CNS?

A number of recent studies have established that the bacterial enzyme chondroitinase ABC promotes functional recovery in the injured CNS. The issue of how it works is rarely addressed, however. The effects of the enzyme are presumed to be due to the degradation of inhibitory chondroitin sulphate GAG chains. Here we review what is known about the composition, structure and distribution of the extracellular matrix in the CNS, and how it changes in response to injury. We summarize the data pertaining to the ability of chondroitinase to promote functional recovery, both in the context of axon regeneration and the reactivation of plasticity. We also present preliminary data on the persistence of the effects of the enzyme in vivo, and its hyaluronan-degrading activity in CNS homogenates in vitro. We then consider precisely how the enzyme might influence functional recovery in the CNS. The ability of chondroitinase to degrade hyaluronan is likely to result in greater matrix disruption than the degradation of chondroitin sulphate alone.

Cellular laserfection.

Many studies in modern biology often rely on the introduction of a foreign molecule (i.e., transfection), be it DNA plasmids, siRNA molecules, protein biosensors, labeled tracers, and so on, into cells in order to answer the important questions of today's science. Many different methods have been developed over time to facilitate cellular transfection, but most of these methods were developed to work with a specific type of molecule (usually DNA plasmids) and none work well enough with difficult, sensitive, or primary cells to meet the needs of current life science researchers. A novel procedure that uses laser light to gently permeabilize large number of cells in a very short time has been developed and is described in detail in this chapter. This method allows difficult cells to be efficiently transfected in a high-throughput manner, with a wide variety of molecules, with extremely low toxicity.

Upregulation of aggrecan, link protein 1, and hyaluronan synthases during formation of perineuronal nets in the rat cerebellum.

Extracellular matrix molecules accumulate around central nervous system neurons during postnatal development, forming so-called perineuronal nets (PNNs). PNNs play a role in restricting plasticity at the end of critical periods. In the adult rat cerebellum, PNNs are found around large, deep cerebellar nuclei (DCN) neurons and Golgi neurons and are composed of chondroitin sulfate proteoglycans (CSPGs), tenascin-R (TN-R), hyaluronan (HA), and link proteins, such as cartilage link protein 1 (Crtll). Granule cells and Purkinje cells are surrounded by a partially organized matrix. Both glial cells and neurons surrounded by PNNs are the site of synthesis of some CSPGs and of TN-R, but only neurons produce HA synthetic enzymes (HASs), thus HA, and link proteins, which are scaffolding molecules for an organized matrix. To elucidate the mechanisms of formation of PNNs, we analyzed by immunohistochemistry and in situ hybridization which PNN components are upregulated during PNN formation in rat cerebellar postnatal development and what cell types express them. We observed that Wisteria floribunda agglutinin-binding PNNs develop around DCN neurons from postnatal day (P)7 and around Golgi neurons from P14. At the same time as their PNNs start to form, these neurons upregulate aggrecan, Crtll, and HASs mRNAs. However, Crtll is the only PNN component to be expressed exclusively in neurons surrounded by PNNs. The other link protein that shows a perineuronal net pattern in the DCN, Bral2, is upregulated later during development. These data suggest that aggrecan, HA, and, particularly, Crtll might be crucial elements for the initial assembly of PNNs.

Evidence for the opposing roles of different gamma delta T cell subsets in macrophage homeostasis.

To ensure invading pathogens are eliminated with minimal damage to host tissues it is essential that macrophage activation be tightly regulated. Previously we demonstrated that a subset of gammadelta T cells (Vgamma1(+)) contributes to resolving pathogen-induced immune responses by killing activated macrophages. However, the exaggerated macrophage response seen in infected Vgamma1(+) T cell-deficient mice suggests that gammadelta T cells play a broader role in macrophage homeostasis and other subsets might promote macrophage activation. Using a macrophage:gammadelta T cell co-culture system we have shown that gammadelta T cells increase the activity of macrophages activated in vivo by Listeria monocytogenes infection. In a dose-dependent manner, gammadelta T cells up-regulated production of cytokines (TNF-alpha, IL-6, IL-10) and chemokines (MIP-1alpha, MIP-1beta) by Listeria-elicited macrophages. The ability to increase macrophage cytokine production was prominent among Vgamma4(+) gammadelta T cells. Reciprocally, Vgamma4(+) gammadelta T cells were activated by Listeria-elicited macrophages, resulting in production of the anti-inflammatory cytokine, IL-10. gammadelta T cell adoptive transfer experiments showed that Vgamma4(+) T cells protected TCRdelta(-/-) mice against Listeria-induced liver injury and necrosis. These findings identify distinct and non-overlapping roles for gammadelta T cell subsets in regulating macrophage function during pathogen-induced immune responses.

Composition of perineuronal net extracellular matrix in rat brain: a different disaccharide composition for the net-associated proteoglycans.

We developed a method to extract differentially chondroitin sulfate proteoglycans (CSPGs) that are diffusely present in the central nervous system (CNS) matrix and CSPGs that are present in the condensed matrix of perineuronal nets (PNNs). Adult rat brain was sequentially extracted with Tris-buffered saline (TBS), TBS-containing detergent, 1 m NaCl, and 6 m urea. Extracting tissue sections with these buffers showed that the diffuse and membrane-bound CSPGs were extracted in the first three buffers, but PNN-associated CSPGs remained and were only removed by 6 m urea. Most of the CSPGs were extracted to some degree with all the buffers, with neurocan, brevican, aggrecan, and versican particularly associated with the stable urea-extractable PNNs. The CSPGs in stable complexes only extractable in urea buffer are found from postnatal day 7-14 coinciding with PNN formation. Disaccharide composition analysis indicated a different glycosaminoglycan (GAG) composition for PGs strongly associated with extracellular matrix (ECM). For CS/dermatan sulfate (DS)-GAG the content of nonsulfated, 6-O-sulfated, 2,6-O-disulfated, and 4,6-O-disulfated disaccharides were higher and for heparan sulfate (HS)-GAG, the content of 6-O-sulfated, 2-N-, 6-O-disulfated, 2-O-, 2-N-disulfated, and 2-O-, 2-N-, 6-O-trisulfated disaccharides were higher in urea extract compared with other buffer extracts. Digestions with chondroitinase ABC and hyaluronidase indicated that aggrecan, versican, neurocan, brevican, and phosphacan are retained in PNNs through binding to hyaluronan (HA). A comparison of the brain and spinal cord ECM with respect to CSPGs indicated that the PNNs in both parts of the CNS have the same composition.

A novel role for Sema3A in neuroprotection from injury mediated by activated microglia.

Microglia exist under physiological conditions in a resting state but become activated after neuronal injury. Recent studies have highlighted the reciprocal role of neurons in controlling both the number and activity of microglia. In this study, microglia derived from newborn rat cortices were cultured and activated by interferon-gamma (IFNgamma) treatment, then exposed to recombinant Sema3A or conditioned medium derived from stressed embryonic cortical neurons. We found that activation of microglia by IFNgamma induced differential upregulation of the semaphorin receptors Plexin-A1 and Neuropilin-1. This result was confirmed by Northern blotting, reverse transcription-PCR, and Western blotting. Furthermore, recombinant Sema3A induced apoptosis of microglia when added to the in vitro culture, and a similar result was obtained on activated microglia when Sema3A was produced by stressed neurons. Using an in vivo model of microglia activation by striatal injection of lipopolysaccharide demonstrated a corresponding upregulation of Plexin-A1 and Neuropilin-1 in activated microglia and enhanced production of Sema3A by stressed adult neurons. These results suggest a novel semaphorin-mediated mechanism of neuroprotection whereby stressed neurons can protect themselves from further damage by activated microglia.

Composition of perineuronal nets in the adult rat cerebellum and the cellular origin of their components.

The decrease in plasticity that occurs in the central nervous system during postnatal development is accompanied by the appearance of perineuronal nets (PNNs) around the cell body and dendrites of many classes of neuron. These structures are composed of extracellular matrix molecules, such as chondroitin sulfate proteoglycans (CSPGs), hyaluronan (HA), tenascin-R, and link proteins. To elucidate the role played by neurons and glial cells in constructing PNNs, we studied the expression of PNN components in the adult rat cerebellum by immunohistochemistry and in situ hybridization. In the deep cerebellar nuclei, only large excitatory neurons were surrounded by nets, which contained the CSPGs aggrecan, neurocan, brevican, versican, and phosphacan, along with tenascin-R and HA. Whereas both net-bearing neurons and glial cells were the sources of CSPGs and tenascin-R, only the neurons expressed the mRNA for HA synthases (HASs), cartilage link protein, and link protein Bral2. In the cerebellar cortex, Golgi neurons possessed PNNs and also synthesized HASs, cartilage link protein, and Bral2 mRNAs. To see whether HA might link PNNs to the neuronal cell surface by binding to a receptor, we investigated the expression of the HA receptors CD44, RHAMM, and LYVE-1. No immunolabelling for HA receptors on the membrane of net-bearing neurons was found. We therefore propose that HASs, which can retain HA on the cell surface, may act as a link between PNNs and neurons. Thus, HAS and link proteins might be key molecules for PNN formation and stability.

Regulation of RPTPbeta/phosphacan expression and glycosaminoglycan epitopes in injured brain and cytokine-treated glia.

Several chondroitin sulfate proteoglycans (CSPGs) are upregulated after CNS injury and are thought to limit axonal regeneration in the adult mammalian CNS. Therefore, we examined the expression of the CSPG, receptor protein tyrosine phosphatase beta (RPTPbeta)/phosphacan, after a knife lesion to the cerebral cortex and after treatment of glial cultures with regulatory factors. The three splice variants of this CSPG gene, the secreted isoform, phosphacan, and the two transmembrane isoforms, the long and short RPTPbeta, were examined. Western blot and immunostaining analysis of injured and uninjured tissue revealed a transient decrease of phosphacan protein levels, but not of short RPTPbeta, in the injured tissue from 1 to 7 days postlesion (dpl). By real time RT-PCR, we show that phosphacan and long RPTPbeta mRNA levels are transiently down-regulated at 2 dpl, unlike those of short RPTPbeta which increased after 4 dpl. In contrast to the core glycoprotein, the phosphacan chondroitin sulfate (CS) glycosaminoglycan epitope DSD-1 was up-regulated after 7 dpl. Phosphacan was expressed by cultivated astrocytes and oligodendrocyte precursors but was more glycanated in oligodendrocyte precursors, which produce more of DSD-1 epitope than astrocytes. Epidermal growth factor/transforming growth factor alpha strongly increased the astrocytic expression of long RPTPbeta and phosphacan and slightly the short RPTPbeta protein levels, while interferon gamma and tumor necrosis factor alpha reduced astrocytic levels of phosphacan, but not of the receptor forms. Examining the effects of phosphacan on axon growth from rat E17 cortical neurons, we found that phosphacan stimulates outgrowth in a largely CS dependent manner, while it blocks the outgrowth-promoting effects of laminin through an interaction that is not affected by removal of the CS chains. These results demonstrate complex injury-induced modifications in phosphacan expression and glycanation that may well influence axonal regeneration and repair processes in the damaged CNS.

A herpesvirus vector can transduce axotomized brain neurons.

If gene therapy is to be used to promote axon regeneration after spinal cord injury, a suitable vector for transgene delivery must be obtained. Replication-defective herpes simplex virus (HSV) vectors are promising candidates. We have examined whether they can express a LacZ transgene in injured neurons of adult rat brain. We transected the medial forebrain bundle, injected replication-defective HSV/LacZ vectors close to the lesion site, and looked for transgene expression at 2-14 days after the lesion. The vectors carried the LacZ transgene controlled either by the cytomegalovirus immediate-early promoter (vector CS5) or the HSV latency-associated promoter (vector CS1). CS5 transfected many cells near the lesion at 2 days, but did not give persistent expression at 5 days. CS1, in contrast, labeled many neurons in midbrain regions remote from the injection site at 5 days, and much of this expression remained at 12-14 days. The neurons of most interest were in the substantia nigra pars compacta and parabrachial nuclei, which were axotomized by the lesion. Vector-driven beta-galactosidase expression was detected in neurons in both regions. These were confirmed as axotomized by double immunofluorescence for c-Jun. By 12-14 days, many substantia nigra neurons had disappeared but some transduced neurons remained; there was no net loss of transduced neurons from the parabrachial nuclei. These results show that an HSV vector is capable of transducing axotomized cells in the central nervous system and producing transgene expression in them for at least 2 weeks after injection.