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Multiple sclerosis (MS) is an inflammatory, demyelinating, and neurodegenerative disease of the central nervous system (CNS) triggered by autoimmune mechanisms. Microglia are critical for the clearance of myelin debris in areas of demyelination, a key step to allow remyelination. TREM2 is expressed by microglia and promotes microglial survival, proliferation, and phagocytic activity. Herein we demonstrate that TREM2 was highly expressed on myelin-laden phagocytes in active demyelinating lesions in the CNS of subjects with MS. In gene expression studies, macrophages from subjects with TREM2 genetic deficiency displayed a defect in phagocytic pathways. Treatment with a new TREM2 agonistic antibody promoted the clearance of myelin debris in the cuprizone model of CNS demyelination. Effects included enhancement of myelin uptake and degradation, resulting in accelerated myelin debris removal by microglia. Most importantly, antibody-dependent TREM2 activation on microglia increased density of oligodendrocyte precursors in areas of demyelination, as well as the formation of mature oligodendrocytes thus enhancing remyelination and axonal integrity. These results are relevant as they propose TREM2 on microglia as a potential new target to promote remyelination. Electronic supplementary material The online version of this article (10.1007/s00401-020-02193-z) contains supplementary material, which is available to authorized users.

Progranulin (PGRN, encoded by the GRN gene) plays a key role in the development, survival, function, and maintenance of neurons and microglia in the mammalian brain. It regulates lysosomal biogenesis, inflammation, repair, stress response, and aging. GRN loss-of-function mutations cause neuronal ceroid lipofuscinosis or frontotemporal dementia-GRN (FTD-GRN) in a gene dosage-dependent manner. Mutations that reduce PGRN levels increase the risk for developing Alzheimer's disease, Parkinson's disease, and limbic-predominant age-related transactivation response DNA-binding protein 43 encephalopathy, as well as exacerbate the progression of amyotrophic lateral sclerosis (ALS) and FTD caused by the hexanucleotide repeat expansion in the C9orf72 gene. Elevating and/or restoring PGRN levels is an attractive therapeutic strategy and is being investigated for neurodegenerative diseases through multiple mechanisms of action.

Background - Inhibitory sialic acid-binding immunoglobulin-type lectins (Siglecs) are a subset of the Siglec family of cell surface receptors that potentiate immune tolerance. A multitude of inhibitory Siglecs on myeloid cells become engaged in sialic acid-rich tumor microenvironments, suggesting that disrupting Siglec-sialic acid signaling could confer therapeutic benefit in cancer. To accomplish this, we designed AL009, an engineered Siglec-9 extracellular domain-Fc fusion molecule that acts as a sialic acid trap and a multi-Siglec inhibitor, repolarizing suppressive myeloid cells and activating an anti-cancer response. Methods - Cooperative binding of AL009 was analyzed by flow cytometry using cultured human tumor cell lines and myeloid-derived suppressor cells (MDSCs) differentiated from primary human monocytes. Monocytes, MDSCs, and macrophages differentiated from primary human monocytes were assessed for AL009 binding by flow cytometry. AL009m (AL009 with a mouse Fc) was fluorophore-labeled and intravenously injected into B6 mice to analyze biodistribution via ex vivo tissue imaging over time. Initial toxicology screening was conducted in cynomolgus monkeys in a non-terminal study. Results - AL009 displays cooperative binding with sialic acid and Fc gamma receptors on myeloid cells. When comparing binding among myeloid cell subsets, AL009 preferentially binds MDSCs. Analysis of the biodistribution of labeled AL009m in mice showed the greatest accumulation in the spleen, consistent with immune cell targeting in vivo. Further, Fc engineering of AL009 improved the pharmacodynamic profile compared to a non-engineered Fc. In cynomolgus monkeys, single doses of 80 mg/kg appeared safe and without clinically significant findings. Conclusions - The engineered structure of AL009 leads to preferential binding to an immunosuppressive subset of myeloid cells. This targeting leads to repolarization of myeloid cells and activates an innate and adaptive anti-cancer response. Pharmacologically relevant doses of AL009 appear well-tolerated in initial studies in non-human primates, supporting further development for entry into clinical studies. Citation Format: Sam Nalle, Helen Lam, Cheryl Barner, Hua Long, Spencer Liang, Arnon Rosenthal, Daniel Maslyar. AL009 is a multi-Siglec inhibitor engineered to bind myeloid cells that enhances innate and adaptive immunity to cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 613.

Wang et al. demonstrate that a mAb specific for the human microglial receptor TREM2 induces microglia proliferation, ameliorates Aβ-induced pathology in a mouse model of Alzheimer’s disease, and can be given safely in a first-in-human phase I clinical trial., TREM2 is a receptor for lipids expressed in microglia. The R47H variant of human TREM2 impairs ligand binding and increases Alzheimer’s disease (AD) risk. In mouse models of amyloid β (Aβ) accumulation, defective TREM2 function affects microglial response to Aβ plaques, exacerbating tissue damage, whereas TREM2 overexpression attenuates pathology. Thus, AD may benefit from TREM2 activation. Here, we examined the impact of an anti-human TREM2 agonistic mAb, AL002c, in a mouse AD model expressing either the common variant (CV) or the R47H variant of TREM2. Single-cell RNA-seq of microglia after acute systemic administration of AL002c showed induction of proliferation in both CV- and R47H-transgenic mice. Prolonged administration of AL002c reduced filamentous plaques and neurite dystrophy, impacted behavior, and tempered microglial inflammatory response. We further showed that a variant of AL002c is safe and well tolerated in a first-in-human phase I clinical trial and engages TREM2 based on cerebrospinal fluid biomarkers. We conclude that AL002 is a promising candidate for AD therapy., Graphical Abstract

Attribute-based access control (ABAC) is a general access control model that subsumes numerous earlier access control models. Its increasing popularity stems from the intuitive generic structure of granting permissions based on application and domain attributes of users, subjects, objects, and other entities in the system. Multiple formal and informal languages have been developed to express policies in terms of such attributes. The utility of ABAC policy languages is potentially undermined without a properly formalized underlying model. The high-level structure in a majority of ABAC models consists of sets of tokens and sets of sets, expressions that demand that the reader unpack multiple levels of sets and tokens to determine what things mean. The resulting reduced readability potentially endangers correct expression, reduces maintainability, and impedes validation. These problems could be magnified in models that employ nonuniform representations of actions and their governing policies. We propose to avoid these magnified problems by recasting the high-level structure of ABAC models in a logical formalism that treats all actions (by users and others) uniformly and that keeps existing policy languages in place by interpreting their attributes in terms of the restructured model. In comparison to existing ABAC models, use of a logical language for model formalization, including hierarchies of types of entities and attributes, promises improved expressiveness in specifying the relationships between and requirements on application and domain attributes. A logical modeling language also potentially improves flexibility in representing relationships as attributes to support some widely used policy languages. Consistency and intelligibility are improved by using uniform means for representing different types of controlled actions---such as regular access control actions, administrative actions, and user logins---and their governing policies. Logical languages also provide a well-defined denotational semantics supported by numerous formal inference and verification tools.

Data standards are a powerful, real-world tool for enterprise interoperability, yet there exists no well-grounded methodology for selecting among alternative standards approaches. We focus on a specific sub-problem within a community's data sharing challenge and identify four major standards-based approaches to that task. We present characteristics of a data sharing community that one should consider in selecting a standards approach--such as relative power, motivation level, and technical sophistication of different participants--and illustrate with real-world examples. These characteristics and other factors are then analyzed to develop decision rules for selecting among the four approaches. Independent of the data exchange problem, we suggest two general practices in choosing a standards approach: (1) vertical decomposition of interoperability issues, in order to define a narrow, formal, tractable problem, and (2) option-exclusion rules, as they are much simpler than stating optimal-choice rules.

One vexing issue in biomedical research is the failure of many therapies to translate from success in animal models to effective treatment of human disease. One significant difference between the animal models and the human disease is the age of the subject. Cancer, stroke and Alzheimer's occur mainly in humans beyond the 75% mean survival age, while most mouse models use juvenile or young adult animals. Here we compare two mouse models of amyloid deposition, the Tg2576 APP model and the more aggressive APP+PS1 model in which a mutant presenilin1 gene is overexpressed with Tg2576. Middle-aged APP+PS1 mice and aged APP mice have similar degrees of amyloid pathology with a few differences that may partially explain some of the differences between the two age cohorts. The first study evaluated production of microhemorrhage by a monoclonal anti-Aβ antibody. We found that in spite of greater amyloid clearance in middle-aged APP+PS1 mice than aged APP mice, the microhemorrhage only developed in old animals. This argues that preclinical studies of immunotherapy in young or middle-aged mice may not predict this potential liability in clinical trials. A second study evaluated the infiltration of systemically injected GFP labeled monocytes into the CNS. Here we find that infiltration is greater in aged mice than middle-aged mice, in spite of greater total Aß staining in the middle-aged animals. We conclude that preclinical studies should be conducted in aged animal models as well as young mice to better prepare for unintended consequences in the human trial.

We examine how the biomedical informatics (BMI) community, especially consortia that share data and applications, can take advantage of a new resource called “cloud computing”. Clouds generally offer resources on demand. In most clouds, charges are pay per use, based on large farms of inexpensive, dedicated servers, sometimes supporting parallel computing. Substantial economies of scale potentially yield costs much lower than dedicated laboratory systems or even institutional data centers. Overall, even with conservative assumptions, for applications that are not I/O intensive and do not demand a fully mature environment, the numbers suggested that clouds can sometimes provide major improvements, and should be seriously considered for BMI. Methodologically, it was very advantageous to formulate analyses in terms of component technologies; focusing on these specifics enabled us to bypass the cacophony of alternative definitions (e.g., exactly what does a cloud include) and to analyze alternatives that employ some of the component technologies (e.g., an institution’s data center). Relative analyses were another great simplifier. Rather than listing the absolute strengths and weaknesses of cloud-based systems (e.g., for security or data preservation), we focus on the changes from a particular starting point, e.g., individual lab systems. We often find a rough parity (in principle), but one needs to examine individual acquisitions—is a loosely managed lab moving to a well managed cloud, or a tightly managed hospital data center moving to a poorly safeguarded cloud?

Synapses are asymmetric cellular adhesions that are critical for nervous system development and function, but the mechanisms that induce their formation are not well understood. We have previously identified thrombospondin as an astrocyte-secreted protein that promotes central nervous system (CNS) synaptogenesis. Here, we identify the neuronal thrombospondin receptor involved in CNS synapse formation as alpha2delta-1, the receptor for the anti-epileptic and analgesic drug gabapentin. We show that the VWF-A domain of alpha2delta-1 interacts with the epidermal growth factor-like repeats common to all thrombospondins. alpha2delta-1 overexpression increases synaptogenesis in vitro and in vivo and is required postsynaptically for thrombospondin- and astrocyte-induced synapse formation in vitro. Gabapentin antagonizes thrombospondin binding to alpha2delta-1 and powerfully inhibits excitatory synapse formation in vitro and in vivo. These findings identify alpha2delta-1 as a receptor involved in excitatory synapse formation and suggest that gabapentin may function therapeutically by blocking new synapse formation.

Background and purpose: Calcitonin gene-related peptide (CGRP) receptor antagonists effectively abort migraine headache and inhibit neurogenic vasodilatation in humans as well as rat models. Monoclonal antibodies typically have long half-lives, and we investigated whether or not function-blocking CGRP antibodies would inhibit neurogenic vasodilatation with a long duration of action and therefore be a possible approach to preventive therapy of migraine. During chronic treatment with anti-CGRP antibodies, we measured cardiovascular function, which might be a safety concern of CGRP inhibition.

Data integration systems often provide a uniform query interface, called a mediated schema , to a multitude of data sources. To answer user queries, such systems employ a set of semantic matches between the mediated schema and the data-source schemas. Finding such matches is well known to be difficult. Hence much work has focused on developing semi-automatic techniques to efficiently find the matches. In this paper we consider the complementary problem of improving the mediated schema , to make finding such matches easier. Specifically, a mediated schema S will typically be matched with many source schemas. Thus, can the developer of S analyze and revise S in a way that preserves S's semantics, and yet makes it easier to match with in the future? In this paper we provide an affirmative answer to the above question, and outline a promising solution direction, called mSeer . Given a mediated schema S and a matching tool M , mSeer first computes a matchability score that quantifies how well S can be matched against using M . Next, mSeer uses this score to generate a matchability report that identifies the problems in matching S. Finally, mSeer addresses these problems by automatically suggesting changes to S (e.g., renaming an attribute, reformatting data values, etc.) that it believes will preserve the semantics of S and yet make it more amenable to matching. We present extensive experiments over several real-world domains that demonstrate the promise of the proposed approach.

Anti-Abeta antibody administration to amyloid-depositing transgenic mice can reverse amyloid pathology and restore memory function. However, in old mice, these treatments also increase vascular leakage and promote formation of vascular amyloid deposits. Deglycosylated antibodies with reduced affinity for Fcgamma receptors and complement are associated with reduced vascular amyloid and microhemorrhage while retaining amyloid-clearing and memory-enhancing properties of native intact antibodies. In the current experiment, we investigated the effect of 3, 10, or 30 mg/kg of deglycosylated antibody (D-2H6) on amyloid pathology and cognitive behavior in old Tg2576 mice. We found that low doses of deglycosylated antibody appear more efficacious than higher doses in reducing pathology and memory loss in amyloid precursor protein (APP) transgenic mice. These data suggest that excess antibody unbound to antigen can interfere with antibody-mediated Abeta clearance, possibly by saturating the FcRn antibody transporter.

Too much cleaning up The complement system and microglia seek out and destroy unwanted cellular debris for the peripheral immune system as well as excess synapses in the developing brain. Hong et al. now show how the system may go haywire in adults early in the progression toward Alzheimer's disease (AD). Aberrant synapse loss is an early feature of Alzheimer's and correlates with cognitive decline. In mice susceptible to AD, complement was associated with synapses, and microglial function was required for synapse loss. The authors speculate that aberrant activation of this “trash disposal” system underlies AD pathology. Science , this issue p. 712

Most recent schema matching systems assemble multiple components, each employing a particular matching technique. The domain user mustthen tune the system: select the right component to be executed and correctly adjust their numerous “knobs” (e.g., thresholds, formula coefficients). Tuning is skill and time intensive, but (as we show) without it the matching accuracy is significantly inferior. We describe eTuner, an approach to automatically tune schema matching systems. Given a schema S, we match S against synthetic schemas, for which the ground truth mapping is known, and find a tuning that demonstrably improves the performance of matching S against real schemas. To efficiently search the huge space of tuning configurations, eTuner works sequentially, starting with tuning the lowest level components. To increase the applicability of eTuner, we develop methods to tune a broad range of matching components. While the tuning process is completely automatic, eTuner can also exploit user assistance (whenever available) to further improve the tuning quality. We employed eTuner to tune four recently developed matching systems on several real-world domains. The results show that eTuner produced tuned matching systems that achieve higher accuracy than using the systems with currently possible tuning methods.

Pain and cachexia are two of the most debilitating aspects of rheumatoid arthritis. Despite that, the mechanisms by which they are mediated are not well understood. We provide evidence that nerve growth factor (NGF), a secreted regulatory protein that controls neuronal survival during development, is a key mediator of pain and weight loss in auto-immune arthritis. Function blocking antibodies to NGF completely reverse established pain in rats with fully developed arthritis despite continuing joint destruction and inflammation. Likewise, these antibodies reverse weight loss while not having any effect on levels of the pro-cachectic agent tumor necrosis factor (TNF). Taken together, these findings argue that pathological joint pain and joint destruction are mechanistically independent processes and that NGF regulates an alternative cachexia pathway that is independent or downstream of TNF.

For meaningful information exchange or integration, providers and consumers need compatible semantics between source and target systems. It is widely recognized that achieving this semantic integration is very costly. Nearly all the published research concerns how system integrators can discover and exploit semantic knowledge in order to better share data among the systems they already have. This research is very important, but to make the greatest impact, we must go beyond after-the-fact semantic integration among existing systems, to actively guiding semantic choices in new ontologies and systems - e.g., what concepts should be used as descriptive vocabularies for existing data, or as definitions for newly built systems. The goal is to ease data sharing for both new and old systems, to ensure that needed data is actually collected, and to maximize over time the business value of an enterprise's information systems.

The role of microglia in the removal of amyloid deposits after systemically administered anti-Abeta antibodies remains unclear. In the current study, we injected Tg2576 APP transgenic mice weekly with an anti-Abeta antibody for 1, 2, or 3 months such that all mice were 22 months at the end of the study. In mice immunized for 3 months, we found an improvement in alternation performance in the Y maze. Histologically, we were able to detect mouse IgG bound to congophilic amyloid deposits in those mice treated with the anti-Abeta antibody but not in those treated with a control antibody. We found that Fcgamma receptor expression on microglia was increased after 1 month of treatment, whereas CD45 was increased after 2 months of treatment. Associated with these microglial changes was a reduction in both diffuse and compact amyloid deposits after 2 months of treatment. Interestingly, the microglia markers were reduced to control levels after 3 months of treatment, whereas amyloid levels remained reduced. Serum Abeta levels and anti-Abeta antibody levels were elevated to similar levels at all three survival times in mice given anti-Abeta injections rather than control antibody injections. These data show that the antibody is able to enter the brain and bind to the amyloid deposits, likely opsonizing the Abeta and resulting in Fcgamma receptor-mediated phagocytosis. Together with our earlier work, our data argue that all proposed mechanisms of anti-Abeta antibody-mediated amyloid removal can be simultaneously active.

The mechanisms by which anti-Abeta antibodies clear amyloid plaques in Abeta depositing transgenic mice are unclear. In the current study, we demonstrate that inhibition of anti-Abeta antibody-induced microglial activation with anti-inflammatory drugs, such as dexamethasone, inhibits removal of fibrillar amyloid deposits. We also show that anti-Abeta F(ab')(2) fragments fail to activate microglia and are less efficient in removing fibrillar amyloid than the corresponding complete IgG. Diffuse Abeta deposits are cleared by antibodies under all circumstances. These data suggest that microglial activation is necessary for efficient removal of compact amyloid deposits with immunotherapy. Inhibition of this activation may result in an impaired clinical response to vaccination against Abeta.

Current big data ecosystems lack a principled approach to metadata management. This impedes large organizations' ability to share data and data preparation and analysis code, to integrate data, and to ensure that analytic code makes compatible assumptions with the data it uses. This use-case paper describes the challenges and an in-progress effort to address them. We present a real application example, discuss requirements for "big metadata" drawn from that example as well as other U.S. government analytic applications, and briefly describe an effort to adapt an existing open source metadata manager to support the needs of big data ecosystems.

Sonic Hedgehog (Shh) is a secreted protein that controls cell fate and mitogenesis in the developing nervous system. Here we show that a constitutively active form of Smoothened (Smo-M2) mimics concentration-dependent actions of Shh in the developing neural tube, including activation of ventral marker genes (HNF3beta, patched, Nkx2.2, netrin-1), suppression of dorsal markers (Pax-3, Gli-3, Ephrin A5) and induction of ventral neurons (dopaminergic, serotonergic) and ventrolateral motor neurons (Islet-1+, Islet-2+, HB9+) and interneurons (Engrailed-1+, CHX10+). Furthermore, Smo-M2's patterning activities were cell autonomous, occurring exclusively in cells expressing Smo-M2. These findings suggest that Smo is a key signaling component in the Hh receptor and that Shh patterns the vertebrate nervous system as a morphogen, rather than through secondary relay signals.

The patterning and morphogenesis of multicellular organisms require a complex interplay of inductive signals which control proliferation, growth arrest, and differentiation of different cell types. A number of such signaling molecules have been identified in vertebrates and invertebrates. The molecular dissection of these pathways demonstrated that in vertebrates, mutations or abnormals function of these signaling pathways were often associated with developmental disorders and cancer formation. The Hedgehog (Hh) family of secreted proteins provides a perfect example of such signaling proteins. In the following review, we will not discuss in detail the role of Hh as a morphogen, but rather focus on its signal transduction pathway and its role in various human disorders.

Large database systems (e.g., federations, warehouses) are multi-layer — i.e., a combination of base databases and (virtual or physical) view databases 1 . Smaller systems use views for layers that hide detailed physical and conceptual structures. We argue that most databases would be more effective if they were more user-centered — i.e., if they allowed users, administrators, and application developers to work mostly within their native view. To do so, we need first class views — views that support most of the metadata and operations available on source tables. First class views could also make multi-tier object architectures (based on objects in multiple tiers of servers) easier to build and maintain. The views modularize code for data services (e.g., query, security) and for coordinating changes with neighboring tiers. When data in each tier is derived declaratively, one can generate some of these methods semi-automatically. Much of the functionality required to support first class views can be generated semi-automatically, if the derivations between layers are declarative (e.g., SQL, rather than Java). We present a framework where propagation rules can be defined, allowing the flexible and incremental specification of view semantics, even by non-programmers. Finally, we describe research areas opened up by this approach.

The mechanism by which pluripotent progenitors give rise to distinct classes of mature neurons in vertebrates is not well understood. To address this issue we undertook a genetic screen for mutations which affect the commitment and differentiation of catecholaminergic (CA) [dopaminergic (DA), noradrenergic (NA), and adrenergic] neurons in the zebrafish, Danio rerio. The identified mutations constitute five complementation groups. motionless and foggy affect the number and differentiation state of hypothalamic DA, telencephalic DA, retinal DA, locus coeruleus (LC) NA, and sympathetic NA neurons. The too few mutation leads to a specific reduction in the number of hypothalamic DA neurons. no soul lacks arch-associated NA cells and has defects in pharyngeal arches, and soulless lacks both arch-associated and LC cell groups. Our analyses suggest that the genes defined by these mutations regulate different steps in the differentiation of multipotent CA progenitors. They further reveal an underlying universal mechanism for the control of CA cell fates, which involve combinatorial usage of regulatory genes.

The multitransmembrane protein Patched (PTCH) is the receptor for Sonic Hedgehog (Shh), a secreted molecule implicated in the formation of embryonic structures and in tumorigenesis. Current models suggest that binding of Shh to PTCH prevents the normal inhibition of the seven-transmembrane-protein Smoothened (SMO) by PTCH. According to this model, the inhibition of SMO signaling is relieved after mutational inactivation of PTCH in the basal cell nevus syndrome. Recently, PTCH2, a molecule with sequence homology to PTCH, has been identified. To characterize both PTCH molecules with respect to the various Hedgehog proteins, we have isolated the human PTCH2 gene. Biochemical analysis of PTCH and PTCH2 shows that they both bind to all hedgehog family members with similar affinity and that they can form a complex with SMO. However, the expression patterns of PTCH and PTCH2 do not fully overlap. While PTCH is expressed throughout the mouse embryo, PTCH2 is found at high levels in the skin and in spermatocytes. Because Desert Hedgehog (Dhh) is expressed specifically in the testis and is required for germ cell development, it is likely that PTCH2 mediates its activity in vivo . Chromosomal localization of PTCH2 places it on chromosome 1p33–34, a region deleted in some germ cell tumors, raising the possibility that PTCH2 may be a tumor suppressor in Dhh target cells.

Glial-cell-line-derived neurotrophic factor (GDNF) [1], neurturin [2] and persephin [3] are structurally related, secreted proteins that are widely expressed in the nervous system and other tissues [1–5] and promote the survival of a variety of neurons during development [1–12]. GDNF and neurturin signal through multicomponent receptors that consist of the Ret receptor tyrosine kinase and one of two structurally related glycosyl-phosphatidylinositol (GPI)-linked ligand-binding subunits: GFR α -1 is the preferred ligand-binding subunit for GDNF, and GFR α -2 is the preferred ligand-binding subunit for neurturin [13–21]. Two additional members of the GFR α family of GPI-linked proteins have recently been cloned: GFR α -3 [21–23] and GFR α -4 [24]. We have shown that persephin binds efficiently only to GFR α -4, and labelled persephin is effectively displaced from cells expressing GFR α -4 by persephin but not by GDNF or neurturin. Using microinjection to introduce expression plasmids into cultured neurons, we have also shown that coexpression of Ret with GFR α -4 confers a marked survival response to persephin but not to GDNF or neurturin. These results demonstrate that GFR α -4 is the ligand-binding subunit for persephin and that persephin, like GDNF and neurturin, also requires Ret for signalling.

Glial cell line-derived neurotrophic factor (GDNF) is a distant member of the TGFbeta protein family that is essential for neuronal survival and renal morphogenesis. We show that mice who are deficient in the glycosyl-phosphatidyl inositol (GPI) -linked protein GFRalpha1 (GDNFRalpha) display deficits in the kidneys, the enteric nervous system, and spinal motor and sensory neurons that are strikingly similar to those of the GDNF- and Ret-deficient mice. GFRalpha1-deficient dopaminergic and nodose sensory ganglia neurons no longer respond to GDNF or to the structurally related protein neurturin (NTN) but can be rescued when exposed to GDNF or neurturin in the presence of soluble GFRalpha1. In contrast, GFRalpha1-deficient submandibular parasympathetic neurons retain normal response to these two factors. Taken together with the available genetic and biochemical data, these findings support the idea that GFRalpha1 and the transmembrane tyrosine kinase Ret are both necessary receptor components for GDNF in the developing kidney and nervous system, and that GDNF and neurturin can mediate some of their activities through a second receptor.

Glial cell line-derived neurotrophic factor (GDNF) exhibits potent effects on survival and function of midbrain dopaminergic (DA) neurons in a variety of models. Although other growth factors expressed in the vicinity of developing DA neurons have been reported to support survival of DA neuronsin vitro, to date none of these factors duplicate the potent and selective actions of GDNFin vivo. We report here that neurturin (NTN), a homolog of GDNF, is expressed in the nigrostriatal system, and that NTN exerts potent effects on survival and function of midbrain DA neurons. Our findings indicate that NTN mRNA is sequentially expressed in the ventral midbrain and striatum during development and that NTN exhibits survival-promoting actions on both developing and mature DA neurons.In vitro, NTN supports survival of embryonic DA neurons, andin vivo, direct injection of NTN into the substantia nigra protects mature DA neurons from cell death induced by 6-OHDA. Furthermore, administration of NTN into the striatum of intact adult animals induces behavioral and biochemical changes associated with functional upregulation of nigral DA neurons. The similarity in potency and efficacy of NTN and GDNF on DA neurons in several paradigms stands in contrast to the differential distribution of the receptor components GDNF Family Receptor α1 (GFRα1) and GFRα2 within the ventral mesencephalon. These results suggest that NTN is an endogenous trophic factor for midbrain DA neurons and point to the possibility that GDNF and NTN may exert redundant trophic influences on nigral DA neurons acting via a receptor complex that includes GFRα1.

During development, distinct classes of neurons are specified in precise locations along the dorso–ventral and anterior–posterior axes of the neural tube. We provide evidence that intersections of Shh, which is expressed along the ventral neural tube, and FGF8, which is locally produced at the mid/hindbrain boundary and in the rostral forebrain, create induction sites for dopaminergic neurons in the midbrain and forebrain. The same intersection, when preceded by a third signal, FGF4, which is expressed in the primitive streak, defines an inductive center for hindbrain 5-HT neurons. These findings illustrate that cell patterning in the neural plate is a multistep process in which early inducers, which initially divide the neural plate into crude compartments, are replaced by multiple local organizing centers, which specify distinct neuronal cell types within these compartments.

Several unifications that the application development process has long needed are now occurring, due to developments in object technologies and standards. These will (gradually) change the way data intensive applications are developed, reduce databases' prominence in this process, and change data administration's goals and participants. At the same time, the database community needs to ensure that its experiences are leveraged and its concerns are met within the new methodologies and toolsets. We discuss these issues, and illustrate how they apply to a portion of the Department of Defense (DOD). We also examine things that object technology won't accomplish, and identify research problems whose solution would enable further progress.

Nerve growth factor (NGF), which has long been considered to be a trophic factor for peripheral sensory and sympathetic neurons, has been found recently to influence cholinergic neurons in the basal forebrain and neostriatum. In the present study, we provide evidence that brainstem neurons in the perihypoglossal area that relay information from the inner ear and vestibular apparatus to the cerebellum and tectum are responsive to NGF. These neurons, which are located in the nucleus prepositus hypoglossi (NPH), spinal vestibular nucleus, cochlear complex, and gigantocellular and paragigantocellular nuclei of the reticular formation, express functional receptors for NGF and up-regulate the expression of trkA receptors after injection of NGF into targets. In addition, the developmental up-regulation of NGF in the cerebellum coincides with the differentiation of the perihypoglossal nuclei. These results suggest that neurons representing the principal brain relays for auditory and vestibular pathways and perihypoglossal neurons involved in gaze coordination are a novel group of central neurons (besides cholinergic neurons in the basal forebrain and neostriatum) that respond to NGF.

Conventional database optimizers take full advantage of associativity and commutativity properties of join to implement e cient and powerful optimizations on select/project/join queries. However, only limited optimization is performed on other binary operators. In this paper, we present the theory and algorithms needed to generate alternative evaluation orders for the optimization of queries containing outerjoins. Our results include both a complete set of transformation rules, suitable for new-generation, transformation-based optimizers, and a bottom-up join enumeration algorithm compatible with those used by traditional optimizers.

Neuromyelitis optica (NMO) is an autoimmune disorder with inflammatory demyelinating lesions in the central nervous system, particularly in the spinal cord and optic nerve. NMO pathogenesis is thought to involve binding of anti-aquaporin-4 (AQP4) autoantibodies to astrocytes, which causes complement-dependent cytotoxicity (CDC) and downstream inflammation leading to oligodendrocyte and neuronal injury. Vasculocentric deposition of activated complement is a prominent feature of NMO pathology. Here, we show that a neutralizing monoclonal antibody against the C1q protein in the classical complement pathway prevents AQP4 autoantibody-dependent CDC in cell cultures and NMO lesions in ex vivo spinal cord slice cultures and in mice. A monoclonal antibody against human C1q with 11nM binding affinity prevented CDC caused by NMO patient serum in AQP4-transfected cells and primary astrocyte cultures, and prevented complement-dependent cell-mediated cytotoxicity (CDCC) produced by natural killer cells. The anti-C1q antibody prevented astrocyte damage and demyelination in mouse spinal cord slice cultures exposed to AQP4 autoantibody and human complement. In a mouse model of NMO produced by intracerebral injection of AQP4 autoantibody and human complement, the inflammatory demyelinating lesions were greatly reduced by intracerebral administration of the anti-C1q antibody. These results provide proof-of-concept for C1q-targeted monoclonal antibody therapy in NMO. Targeting of C1q inhibits the classical complement pathway directly and causes secondary inhibition of CDCC and the alternative complement pathway. As C1q-targeted therapy leaves the lectin complement activation pathway largely intact, its side-effect profile is predicted to differ from that of therapies targeting downstream complement proteins.

Data standards are a powerful, real-world tool for enterprise interoperability, yet there exists no rigorous methodology for selecting among alternative standards approaches. This paper is a first step toward creating a detailed engineering basis for choosing among standards approaches. We define a specific sub-problem within a community’s data sharing challenge, and focus on it in depth. We describe the major choices (kinds of standards) applied to that task, examining tradeoffs. We present characteristics of a data sharing community that one should consider in selecting a standards approach—such as relative power, motivation level, and technical sophistication of different participants—and illustrate with real-world examples. We then show that one can state simple decision rules (based on engineering experience) that system engineers without decades of data experience can apply. We also comment on the methodology used, extracting lessons (e.g., “negative rules are simpler”) that can be used in similar analyses on other issues.

Glial-cell-line-derived neurotrophic factor (GDNF) is a potent survival factor for central and peripheral neurons, and is essential for the development of kidneys and the enteric nervous system. Despite the potential clinical and physiological importance of GDNF, its mechanism of action is unknown. Here we show that physiological responses to GDNF require the presence of a novel glycosyl-phosphatidylinositol (GPI)-linked protein (designated GDNFR-alpha) that is expressed on GDNF-responsive cells and binds GDNF with a high affinity. We further demonstrate that GDNF promotes the formation of a physical complex between GDNFR-alpha and the orphan tyrosin kinase receptor Ret, thereby inducing its tyrosine phosphorylation. These findings support the hypothesis that GDNF uses a multi-subunit receptor system in which GDNFR-alpha and Ret function as the ligand-binding and signalling components, respectively.

Our understanding of patterning along the dorsoventral (DV) axis has been advanced by embryological studies which have allowed the identification of dorsal and ventral organizing centers, and of molecular signals that can actin vitroto specify cell fate. However, in order to establish anin-vivorole for a signal it is necessary to show that the molecule is present in the right place and time, that exogenous addition or ectopic expression of the signal mimics its proposed effect and that deletion of its activity results in an absence of the presumed biological response. Such evidence can be provided by gene deletion (knock-out) or ectopic expression (transgenic) studies. In this review, experimental embryological studies that have increased our understanding of DV patterning will be discussed, and studies in which gene manipulation has provided evidence about the in-vivo role of a molecule will be highlighted.

Developing chick motoneurons depend on as yet unidentified factors from the periphery and the central nervous system for their survival. Using cultures of purified embryonic motoneurons, we show that basic fibroblast growth factor (FGF-2) or transforming growth factor-beta 3 (TGF beta 3) each have only low survival-promoting activity when tested alone, but act synergistically to keep motoneurons alive for at least 3 days. Glial cell line-derived neurotrophic factor (GDNF), another member of the TGF beta family, was itself sufficient to maintain a population of motoneurons. However, its effect was not significantly increased by the addition of FGF-2. These results suggest that FGF-2, TGF beta 3, and GDNF, which are all present in the environment of developing motoneurons, may act different mechanisms as physiological survival factors for this population of central neurons.