The Human Connectome Project of adolescent anxiety and depression dataset.

This article describes primary data and resources available from the Boston Adolescent Neuroimaging of Depression and Anxiety (BANDA) study, a novel arm of the Human Connectome Project (HCP). Data were collected from 215 adolescents (14-17 years old), 152 of whom had current diagnoses of anxiety and/or depressive disorders at study intake. Data include cross-sectional structural (T1- and T2-weighted), functional (resting state and three tasks), and diffusion-weighted magnetic resonance images. Both unprocessed and HCP minimally-preprocessed imaging data are available within the data release packages. Adolescent and parent clinical interview data, as well as cognitive and neuropsychological data are also included within these packages. Release packages additionally provide data collected from self-report measures assessing key features of adolescent psychopathology, including: anxious and depressive symptom dimensions, behavioral inhibition/activation, exposure to stressful life events, and risk behaviors. Finally, the release packages include 6- and 12-month longitudinal data acquired from clinical measures. Data are publicly accessible through the National Institute of Mental Health Data Archive (ID: #2505).

Study of regeneration in the garfish olfactory nerve.

Previous studies of the olfactory nerve, mainly in higher vertebrates, have indicated that axonal injury causes total degeneration of the mature neurons, followed by replacement of new neuronal cells arising from undifferentiated mucosal cells. A similar regeneration process was confirmed in the garfish olfactory system. Regeneration of the nerve, crushed 1.5 cm from the cell bodies, is found to produce three distinct populations of regenerating fibers. The first traverses the crush site 1 wk postoperative and progresses along the nerve at a rate of 5.8 +/- 0.3 mm/d for the leading fibers of the group. The second group of fibers traverses the crush site after 2 wk postcrush and advances at a rate of 2.1 +/- 0.1 mm/d for the leading fibers. The rate of growth of this group of fibers remains constant for 60 d but subsequently falls to 1.6 +/- 0.2 for the leading population of fibers. The leading fibers in the third group of regenerating axons traverse the crush site after 4 wk and advance at a constant rate of 0.8 +/- 0.2 mm/d. The multiple populations of regenerating fibers with differing rates of growth are discussed in the context of precursor cell maturity at the time of nerve injury and possible conditioning effects of the lesion upon these cells. Electron microscopy indicates that the number of axons decreases extensively after crush. The first two phases of regenerating axons represent a total of between 6 and 10% of the original axonal population and are typically characterized by small fascicles of axons surrounded by Schwann cells and large amounts of collagenous material. The third phase of fibers represents between 50 and 70% of the original axonal population.

Rapid axonal transport of sulfated mucopolysaccharide proteins.

When sulfur-35-labeled sodium sulfate is injected intraocularly in the goldfish, labeled sulfated mucopolysaccharides rapidly appear in the contra-lateral optic tectum of the brain, demonstrating the axonal flow of sulfated mucopolysaccharides. The transport rate is the same as that observed for proteins labeled after intraocular injection of tritiated proline. Treatment of the sulfur-35-labeled material with precipitants and enzymes reveals the presence of substances with properties similar to those of heparan sulfate (the major component) and chondroitin sulfate. Dermatan sulfate was not detected.

Afferent regulation of cytochrome-c and active caspase-9 in the avian cochlear nucleus.

During development, a subpopulation (approximately 30%) of neurons in the avian cochlear nucleus, nucleus magnocellularis (NM), dies following removal of the cochlea. It is clear that neuronal activity coming from the auditory nerve provides trophic support critical for cell survival in the NM. Several aspects of the intracellular signaling cascades that regulate apoptosis have been defined for naturally occurring, or programmed cell death, in neurons. These intracellular cascades involve the extrusion of cytochrome-c from the mitochondria into the cytosol and the subsequent activation of proteolytic caspase cascades, which ultimately act on substrates that lead to the death of the cell. In contrast, the intracellular signaling cascades responsible for deafferentation-induced cell death are not fully understood. In the present series of experiments, the potential extrusion of cytochrome-c from the mitochondria into the cytosol, and the activation of caspases were examined in the NM following deafferentation. Cytochrome-c immunoreactivity increased within 6 h following deafferentation and persisted for at least 3-5 days following surgery. However, cytochrome-c was not detectable within immunoprecipitates obtained from cytosolic fractions of deafferented NM neurons. This suggests that the increased immunoreactivity of cytochrome-c is related to mitochondrial proliferation. As a positive control, cytochrome-c was detected in cytosolic fractions of deafferented NM neurons treated with kainic acid, a substance known to cause cytochrome-c release into the cytosol. In addition, immunoreactivity for downstream active caspase-9 did increase following cochlea ablation. This increase was observed within 3 h following cochlea removal, but was not observed 4 days following surgery, a time point after the dying population of NM neurons have already degenerated. Together, these findings suggest that deafferentation of NM neurons results in caspase activation, but this activation may be cytochrome-c independent.

Association of proteins undergoing slow axonal transport with goldfish visual system myelin.

[3H]Proline derived radioactivity which is slowly transported in the goldfish optic nerve has been isolated in association with purified preparations of optic tectal myelin. Acrylamide gel analysis reveals that most of the slowly transported radioactivity is distributed among the high molecular weight myelin proteins with a major peak comigrating with a band (approximately 42,000 daltons) which is prominent in goldfish brain myelin. A similar peak is not seen in gels of whole synaptosome protein. Relatively small but measureable amounts of radioactivity comigrate with the basic and proteolipid proteins. A low density myelin subfraction is 3-5 fold lower in specific radioactivity (disint./min/mug protein) than a corresponding high density fraction and shows particularly low specific radioactivities in the basic and proteolipid bands. The results are discussed with reference to the possible adherence of specific axonal membrane fragments as well as other potential sources of myelin label.

Axonal transport of glycoproteins in regenerating olfactory nerve: enhanced glycopeptide concanavalin A-binding.

The size and concanavalin A-binding characteristics of glycopeptides derived from axonally transported glycoproteins were studied in regenerating garfish olfactory nerve. A regeneration related increase was observed in the proportion of total glycopeptide radioactivity associated with the lower molecular weight, dialyzable fraction. There was also a 3-5 fold increase in the axonal transport of low molecular weight concanavalin. A-binding glycopeptides in regenerating nerve. These results suggest a shift to an enhanced synthesis and axonal transport of glycoproteins containing low molecular weight, concanavalin A-binding carbohydrate chains in regenerating nerve.

Isolation of axonally transported glycoproteins with goldfish visual system myelin.

[3H]fucose labeled glycoproteins which are rapidly transported in the goldfish optic nerve have been isolated with purified preparations of goldfish optic tectal myelin. SDS acrylamide gels of myelin proteins isolated one day after intraocular injection of fucose show a broad distribution of radioactivity among high molecular weight proteins. At progressively longer times after injection there is a shift in the distribution of radioactivity with the buildup of a peak of label with electrophoretic mobility corresponding to a molecular weight of approximately 50,000. There is no corresponding peak of radioactivity in gels of total tectal membranes. Gels of myelin labeled through intracranial injections of fucose also show no single prominent peak of radioactivity. Results are discussed with reference to possible mechanisms for the shift in radioactivity patterns on gels and the possible functional significance of the myelin-associated glycoproteins.

Enhanced axonal transport of glycosaminoglycans in regenerating goldfish optic nerve.

Glycosaminoglycans (GAGs) derived from axonally transported proteoglycans were evaluated in regenerating goldfish optic tracts. Fish were administered unilateral optic nerve crushes and stored for 21 days at 21 degrees C. Retinas were labeled by bilateral injection of 35SO4 and sulfated macromolecules axonally transported to the optic tracts were analyzed 8 h postinjection. Results show regenerating tracts contain 6.7-fold more transported 35SO4 in GAGs than their contralateral intact counterparts. Further analysis revealed that regenerating tract GAGs were comprised of 60% chondroitin (4 or 6) sulfate (CS) and 40% heparan sulfate (HS), while unoperated tract GAGs contained 26% CS and 74% HS. These results indicate that there is a large regeneration related increase in the axonal transport of proteoglycans and particular enrichment of transported molecules containing CS chains. The findings can be viewed in the context of recent implication of axonal proteoglycans in processes of fiber outgrowth, adhesion and induction of glial mitosis.

Differences in the efficiency and pattern of incorporation of [3H]leucine and [3H]proline into proteins of adult cat brain.

Previous EM autoradiographic studies have shown that injection of [3H]proline ([3H]Pro) into the cat dorsal column nuclei (DCN) results in heavy labeling of macroglia but negligible labeling of DCN neurons. [3H]Leucine ([3H]Leu), in contrast, was extensively incorporated into both neurons and glia. We now report preliminary assessment of differences in molecular labeling patterns produced by the two amino acid precursors in DCN injection sites (24 h following injection; equal amounts of [3H]Pro and [3H]Leu of equal specific radioactivity). [3H]Pro, despite its lack of incorporation into neurons, labeled DCN to a significantly greater extent than [3H]Leu (30.0 dpm/micrograms protein/microCi for [3H]Pro vs 11.7 dpm/micrograms protein/microCi for [3H]Leu). Greater than 90% of the radioactivity from both precursors was recovered in protein as opposed to TCA soluble or ethanol soluble molecules. Of the [3H]Pro- or [3H]Leu-derived radioactivity recovered in protein, greater than 94% was found to remain in the original precursor form. Fluorographic analysis of SDS acrylamide gels showed labeling of a wide variety of individual proteins with either amino acid. However, particular molecular weight classes were relatively more heavily labeled with either [3H]Leu (47, 63, 77 kDa) or [3H]Pro (22, 45, 50, 66, 80 kDa). Overall the results indicate that the difference in cellular distribution of incorporated [3H]Pro and [3H]Leu, as observed by EM autoradiography is a reflection of the extent of labeling and specific labeling pattern of proteins isolated from the tissue.

Composition and subcellular distribution of glycoproteins and glycosaminoglycans undergoing axonal transport in garfish olfactory nerves.

The study examined the subcellular distribution of [3H]glucosamine-labeled glycoconjugates undergoing axonal transport in 100,000 x g soluble and two membranous subfractions of the garfish olfactory nerve. Analysis was made of intact glycoconjugates and of glycopeptides and glycosaminoglycans derived from these molecules by limit protease digestion. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed labeling of a variety of high-molecular-weight molecules with a lower molecular weight distribution in the soluble fraction than in the membranous fractions. Following protease digestion, nearly two-thirds of transported radioactivity in glycopeptides was recovered in the plasma membrane-enriched subfraction, with the remainder equally divided between soluble and higher density membrane fraction. Comparison of the distribution of glycopeptide radioactivity and chemically assayed hexosamine revealed transport labeling of a large variety of different-sized neutral and acidic glycopeptides in all subfractions. Transport labeling of most glycoprotein carbohydrate chains was in proportion of their hexosamine content. Transported glycosaminoglycan label was most heavily concentrated in the plasma membrane fraction, whereas hexosamine was most concentrated in the higher density membrane fraction. The labeling pattern suggested both transported and nontransported pools of these molecules. The specific glycosaminoglycans chondroitin sulfate and heparan sulfate were recovered in all subfractions, whereas hyaluronic acid was confined to the soluble fraction.

Further characterization of axonally transported proteoglycans.

We report further analysis of axonally transported proteoglycans in soluble and membranous subfractions of goldfish optic tectum. Distribution of transported 35SO4 radioactivity was 35.2% soluble, 63.4% Triton-NaCl extractable and 1.4% unextracted. Proteoglycans isolated on DEAE cellulose were treated with chondroitinase AC or nitrous acid and remaining heparan sulfate proteoglycans (HSPGs) and chondroitin sulfate proteoglycans (CSPGs) were sized on Sepharose CL-6B. Kav values and estimated molecular weights were: Soluble CSPG-0.36 (160 kDa), Triton-NaCl extracted CSPG-.031 (200 kDa), Soluble HSPG-0.37 (150 kDa), Triton-NaCl extracted HSPG-0.37 (150 kDa). For constituent CS and HS chains the Kav values and estimated molecular weights on CL-6B were: Soluble CS-0.55 (15 kDa), Triton-NaCl extracted CS-0.55 (15 kDa), Soluble HS-0.59 (13 kDa) and Triton-NaCl extracted HS-0.65 (9 kDa). CS was shown to be sulfated exclusively at carbon 4 for both soluble and Triton NaCl extracted fractions.

Differential extraction of axonally transported proteoglycans.

Axonally transported proteoglycans were differentially solubilized by a sequence of extractions designed to infer their relationship to nerve terminal membranes. Groups of goldfish were injected unilaterally with 35SO4 and contralateral optic tecta containing axonally transported molecules were removed 16 h later. Tecta were homogenized in isotonic buffer and centrifuged at 100,000 g for 60 min to create a "total supernatant" fraction. Subsequent homogenizations followed by recentrifugation were with hypotonic buffer (lysis extract), 1 M NaCl, Triton X-100 or alternatively Triton-1 M NaCl. Populations of proteoglycans in each extract were isolated on DEAE ion exchange columns and evaluated for content of glycosaminoglycans (GAGs). Results show the distribution of transported proteoglycans to be 26.3% total soluble, 13.7% lysis extract, 13.8% NaCl extract, 12.2% Triton extract, and 46.2% Triton-NaCl extract. Proteoglycans from all fractions contained heparan sulfate as the predominant GAG, with lesser amounts of chondroitin (4 or 6) sulfate. The possible localizations of transported proteoglycans suggested by the extraction results are discussed.

Structural analysis of glycosaminoglycans derived from axonally transported proteoglycans in regenerating goldfish optic nerve.

Structural characteristics of glycosaminoglycans (GAGs) derived from axonally transported proteoglycans (PGs) were compared in 21 days regenerating and intact goldfish optic tracts. Twenty one days following unilateral optic nerve crushes, fish received intraocular injections of 35SO4. Eight hours post injection, tracts were removed and the 35SO4-labeled GAGs, chondroitin sulfate (CS) and heparan sulfate (HS), isolated. The HS from regenerating optic tracts had a DEAE elution profile indicative of decreased charge density, while heparitinase treatment of HS followed by Sephadex G50 analysis of the resulting fragments showed a change in the elution pattern, suggesting reduced overall sulfation. HPLC analysis of HS disaccharides revealed a difference in the sulfation pattern of regenerating tract HS, characterized by the reduced presence of tri-sulfated disaccharides. Other structural features, such as the sizes of CS and HS, and the sulfation of CS, showed no changes during regeneration. These results indicate that changes in the structure of axonally transported HS accompany regeneration of goldfish optic axons.

Inhibition of proteoglycan synthesis influences regeneration of goldfish retinal axons on polylysine and laminin.

Previous studies have shown that goldfish retinal axons regenerating in vivo transport increased radioactivity in the glycosaminoglycan (GAG) components of proteoglycans (PGs). During this enhanced transport, the ratio of chondroitin sulfate (CS) to heparan sulfate (HS) was 60/40. In the present investigation, PG synthesis was inhibited during in vitro axon growth from regenerating goldfish retinal explants. Explants growing on either poly-L-lysine (PLYS) or poly-L-lysine + laminin (PLYS + LN) incorporated 35SO4 into proteoglycan-bound CS and HS in an approximate 2/1 ratio. Addition of 4-methylumbelliferyl beta-D-xyloside (beta-xyloside) to the culture medium reduced the sulfate radioactivity in proteoglycan-bound CS and HS by 89 and 71%, respectively, on PLYS and by 89 and 72% on PLYS + LN. Morphological evaluation of explants revealed that beta-xyloside treatment reduced both the number of retinal axons per explant and their growth rate on PLYS; on PLYS + LN this treatment reduced the number of axons, but had no effect on growth rate. This study suggests that retinal ganglion cell PGs containing CS and/or HS GAG chains are required for both the initiation and the maintenance of axonal outgrowth on artificial polycationic substrata such as PLYS, but only for the initiation of outgrowth on laminin.

Rate of movement and composition of rapidly transported proteins in regenerating olfactory nerve.

In a previous study, three successive groups of regenerative fibers, growing initially at 5.8, 2.1, and 0.8 mm/day, were observed in the regenerating garfish olfactory nerve. In the present study, fast axonal transport in the most rapidly regenerating axons (phase I and II) has been examined. Rapid transport in phase I fibers occurs at a velocity of 208 +/- 9 mm/day at 23 degrees, a rate identical to that measured in intact nerves. This first phase of regenerating fibers represents only 3 to 5% of the original axonal population, but each fiber appears to contain 6 to 16 times more transported radioactivity than an axon in an intact nerve. Subcellular distribution of rapidly moving material in phase I and II fibers was closely related to the distribution obtained in intact nerves. Small but significant differences indicate a shift of the transported radioactivity from a heavier to a light axonal membranous fraction. This shift might be characteristic of the immature membrane of a growing axon. The polypeptide distribution of transported radioactivity was also very similar to that of a normal nerve, with most of the radioactivity associated with high-molecular-weight polypeptides.

Differential turnover of axonally transported glycoproteins.

Metabolic turnover of axonally transported glycoproteins has been examined in membranous and soluble subfractions of goldfish optic tectum following intraocular injection of [3H]fucose. Radioactivity in total transported glycoproteins reached a maximum in the tectum after 24-30 hr, then declined with a half-life of approximately 20 days. Radioactivity in the total membranous subfraction declined with a similar half-life of 20-21 days while radioactivity in the soluble fraction showed a significantly shorter half-life of approximately seven days. Various sized glycopeptides derived from the membranous subfraction showed differential rates of loss of radioactivity with the lower molecular weight nondialyzable molecules displaying the most rapid turnover. In contrast, the glycopeptides derived from the soluble fraction showed relatively uniform rates of turnover. The results are discussed in the context of metabolic compartmentalization between membranous and soluble glycoproteins and among the carbohydrate chains of the membranous molecules.

Chondroitin 4-sulfate stimulates regeneration of goldfish retinal axons.

Our previous studies demonstrated that optic nerve regeneration in the goldfish is accompanied by significantly enhanced axonal transport of glycosaminoglycans (GAGs), with a particularly large increase in the transport of chondroitin 4-sulfate (C4S). We have further shown that inhibition of proteoglycan (PG) synthesis and transport with beta-xyloside impedes axonal outgrowth from regenerating retinal explants. These results suggest a role for PGs that contain C4S in the regeneration process. To begin to address the possible functions of C4S GAGs during regeneration of goldfish retinal axons, we evaluated the effect of exogenous C4S on axonal outgrowth from regenerating retina, explanted 7-14 days after optic nerve crush. Our results indicate that exogenous C4S added to the culture medium potentiates axonal outgrowth on both polylysine- and LN-containing substrata. At low C4S concentrations, this potentiation is more marked on substrata containing both polylysine and LN than on polylysine alone. These results obtained in vitro suggest that soluble C4S, whether arising after axonal transport and externalization or after release from nonneuronal cells, is a positive modulator of regenerative axonal outgrowth in vivo.

Characterization of axonally transported glycoproteins in regenerating garfish olfactory nerve.

This study examined changes in composition and concanavalin A (Con A) binding of axonally transported glycoproteins and their pronase-generated glycopeptides in regenerating garfish olfactory nerve. A previous study had demonstrated a regeneration-related increase in the proportion of [3H]glucosamine label in lower-molecular-weight Con A-binding glycopeptides derived from transported glycoproteins. Further analysis of carbohydrate composition shows that these molecules resemble mannose-rich oligosaccharides in composition and are increased in absolute amount in regenerating nerve. Subcellular analysis shows that the Con A-binding glycopeptides are enriched in membrane subfractions, particularly in a high-density fraction that morphologically resembles isolated cell surface coat. Regeneration-related changes in intact axonally transported glycoproteins were also detected. Sodium dodecyl sulfate gel electrophoresis of transport-labeled glycoproteins disclosed growth-correlated increases in radioactivity associated with 180-200K, 105-115K, and 80-90K components, while a 150-160K molecular weight class of glycoproteins was diminished in relative labeling. Intact glycoproteins displaying an affinity for Con A were also augmented in regenerating nerve, the increases occurring primarily in molecules in the 50-140K range.

Association of axonally transported heparan sulfate with isolated synaptic plasma membrane.

Studies on isolated synaptic plasma membranes (SPM) have detected little if any heparan sulfate or other glycosaminoglycans (GAGs), while more recent studies employing proteoglycan antibodies have localized heparan sulfate proteoglycan in presynaptic plasma membrane of intact tissue. To further address the issue of proteoglycans in synaptic plasma membrane, we have investigated the possible presence of axonally transported GAGs in SPM isolated from the goldfish optic tectum. SPMs isolated from tecta following rapid axonal transport of 35SO4 labeled molecules down the optic nerve, showed specific radioactivity approximately two-fold higher than the starting homogenate. Treatment of the transport labeled SPM with the enzyme heparitinase liberated 21% of the radioactivity, indicating the presence of a significant fraction of transported label in heparan sulfate. In a separate series of experiments a GAG fraction was isolated from transport labeled SPM and was found to consist of heparan sulfate containing 28% of transported radioactivity. Chondroitin (4 or 6) sulfate, which undergoes axonal transport in the goldfish optic system, was not found associated with SPM. Taken together the results support immunological evidence for the presence of heparan sulfate proteoglycans in presynaptic plasma membrane.

Study of a floating fraction obtained during preparation of myelin from degenerating goldfish optic tract.

A floating fraction that layers on top of 0.25 sucrose has been obtained during the preparation of myelin from intact and 9 day degenerating goldfish optic tracts. The proportion of total tract protein isolated in floating fraction rises from 6.6% to 11.0% during degeneration. This increase is paralleled by a morphologically observed splitting of myelin lamellae. Floating fraction contains all of the major myelin proteins but shows a 40% increase in the proportion of basic protein and a 2-3 fold decrease in the proportion of IP proteins (intermediate molecular weight glycoproteins) and a 36 Kd (X) protein. The lipid to protein ratio is slightly higher in floating fraction than myelin. Lipid composition is characterized by 1/2-1/3 the myelin levels of galactolipids and twofold increased levels of triglycerides and cholesterol esters. Electron microscopy of floating fraction shows a mixture of myelin fragments with few lamellae and single membrane fragments. Taken together the results indicate that floating fraction in the degenerating goldfish optic tract is at least partially derived from the breakdown of myelin.