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J A Kessler

Publications and source records attributed to J A Kessler.

At least 73 records · Page 4Linked to original sources
PubMed1995

Neurotrophic factors in the therapy of peripheral neuropathy.

Neurotrophic factors are proteins that promote the survival and differentiation of specific populations of neurones. With the successful cloning and large-scale production of many different neurotrophic factors, it has become practical to consider their application in the treatment of neurological disease. Several groups of neurotrophic factors hold particular promise for the therapy of peripheral nervous system disease in the near future. These include the neurotrophin gene family, cytokines such as CNTF and the IGF family. Evidence is accumulating that an abnormal availability of some of these factors may contribute towards the pathophysiology of some types of neuropathy, most notably diabetic neuropathy. Pre-clinical studies in animal models have demonstrated the likely efficacy of factors such as NGF for small-fibre sensory neuropathy, BDNF, CNTF and IGF-I for motor neurone disease, and NT-3 for large-fibre neuropathy. Clinical trials of several growth factors are currently underway for the treatment of peripheral nerve disease, and other clinical trials are currently being planned.

Diabetic Neuropathies↗
PubMed1995

Cytokines and neuronal differentiation.

A diverse spectrum of complementary experimental investigations has demonstrated that two major cytokine superfamilies, the transforming growth factor-beta (TGF beta) and the hemopoietins, mediate an extensive range of developmental events in the nervous system that often rivals and frequently exceeds that of the classic neurotrophins. The exponential growth in the identification and physiological analysis of TGF beta subclasses of cytokines that transduce intracellular signals through intrinsic membrane serine/threonine kinase-associated receptor subunits has led to an increased understanding of their complex cellular actions in programming the temporospatial expression and maturation of anatomically distinct neuronal subpopulations. An analysis of the developmental parallels that exist between neural development and hematolymphopoiesis has fostered an expansion in the identification and classification of cellular actions of hematolymphopoietic cytokines that are also active during neural development. During the process of neural maturation, it has also become apparent that an extensive range of cell surface-associated and intracellular signalling molecules that are essential for hematopoietic and immunological development may also represent an important set of effector molecules that are active during neuronal differentiation. These recent advances in cell and molecular biology have allowed us to begin to construct an integrated model of the developmental signalling pathways and diverse cellular processes that are necessary for graded stages of neuronal maturation. These cumulative observations suggest that a dynamic hierarchy of epigenetic and genetic signals is essential for the growth, survival, and maturation of regional neuronal subpopulations that are derived from multipotent progenitor species within the central and peripheral nervous systems.

Animals↗
PubMed1994

Neutralization of divergent human immunodeficiency virus type 1 variants and primary isolates by IAM-41-2F5, an anti-gp41 human monoclonal antibody.

The antiviral characteristics of monoclonal antibody IAM-41-2F5 (2F5) were determined in cell culture. The antibody had been previously shown to bind a specific sequence, ELDKWA, within the external domain of the gp41 envelope glycoprotein human immunodeficiency virus type 1 (HIV-1). Selection by 2F5 of recombinant phage from an epitope library confirmed the identification of the antibody's binding determinant. The antibody was found to be capable of neutralizing a broad range of lymphoid cell culture-adapted HIV-1 variants as well as HIV-1 primary isolates. Sequence analysis of the latter showed that neutralization was related to the presence of the antibody binding site. From kinetic measurements using an epitope-containing peptide or gp41, the half-time of dissociation for 2F5 was determined to be 122 min for the peptide and 156 min for gp41. The region of gp41 expressing this sequence exhibits greater conservation among HIV-1 isolates than do the variable domains of gp120.

Amino Acid Sequence↗
PubMed1994

Nerve growth factor administration protects against experimental diabetic sensory neuropathy.

Small fiber sensory neuropathy is one of the most common complications of diabetes mellitus. Currently there is no adequate therapy to prevent this often debilitating problem. Nerve growth factor (NGF) is a protein that promotes the survival and integrity of a large percentage of sensory neurons including the small fiber pain transmitting neurons which are often prominently affected in diabetic neuropathy. We report here that exogenously administered NGF is capable of preventing the behavioral and biochemical manifestations of diabetic sensory neuropathy in a streptozocin induced rat model. NGF administration prevented the elevation of tailflick threshold (a measure of the rat's response to a thermal noxious stimulus) which occurred in streptozocin-induced diabetic rats. Further, it prevented the induced reduction in levels of the neuropeptides substance P and calcitonin gene related peptide measured from cervical dorsal root ganglia. Finally, NGF did not ameliorate the prolonged latency of the compound action potentials measured from the caudal nerve of the tail. In view of these results, a clinical trial of NGF in diabetic neuropathy has now commenced.

Action Potentials↗
PubMed1994

Evidence for hypoxia-induced, programmed cell death of cultured neurons.

Apoptosis, a form of cell death ("programmed" cell death) in which the nucleus and cytoplasm shrink and often fragment, serves to eliminate excessive or unwanted cells during remodeling of embryonic tissues, during organ involution, and in tumor regression. In acute pathological states, such as ischemia, the cells tend to swell and lyse--a process called necrosis. We hypothesize that the delayed neural death clinically associated with hypoxia may, in part, represent apoptosis. A tissue culture model of 24 hours of hypoxia was employed using sympathetic neurons. Pretreatment with an endonuclease inhibitor (aurintricarboxylic acid) decreased cell death by 53%, depolarizing conditions (55 mM potassium chloride) decreased cell death by 33%, and an RNA synthesis inhibitor (actinomycin D) by 26% (all have been shown to prevent apoptosis). Pretreatment with antisense c-myc had no effect. Fluorescent staining with propidium iodide (a DNA marker) demonstrated chromatin condensation and agarose gel electrophoresis demonstrated a DNA "ladder." These data suggest that apoptosis may play a role in hypoxic cell death and that in this paradigm, expression of c-myc is unnecessary. This would suggest a new approach to our understanding of hypoxia and open new strategies to lessen neuronal damage secondary to this process.

Animals↗
PubMed1994

Viral transduction of trkA into cultured nodose and spinal motor neurons conveys NGF responsiveness.

The trkA gene encodes the tyrosine kinase receptor that transduces the NGF signal. We have used a defective herpes simplex virus-1 (HSV-1) vector containing a full-length rat trkA sequence (pHSVtrkA) to express NGF receptors in primary cultures of neonatal nodose neurons and embryonic spinal motor neurons which are normally unresponsive to NGF. Transduction of rat neonatal nodose ganglion neurons and spinal motor neurons with pHSVtrkA resulted in expression of functional NGF receptors. Stimulation of these receptors by NGF resulted in the survival and the morphologic and biochemical differentiation of these neurons. These observations indicate that nodose and spinal motor neurons can express the downstream signal transduction apparatus necessary to mediate the survival and differentiating effects mediated by ligand binding to trkA and that transduction with pHSVtrkA can effectively convert NGF nonresponsive neurons into responsive ones.

Animals↗
PubMed1994

mRNAs encoding muscarinic and substance P receptors in cultured sympathetic neurons are differentially regulated by LIF or CNTF.

Leukemia inhibitory factor (LIF) and ciliary neurotrophic factor (CNTF) have previously been shown to regulate neuronal choice of neurotransmitter. In this present study, these factors were shown to specifically and differentially regulate levels of both muscarinic (subtypes m1, m2, m3, m4, and m5) and substance P receptor (SPR) mRNAs in sympathetic neurons of the rat superior cervical ganglion (SCG) using solution hybridization/RNase protection analysis. In vivo, neonatal rat SCG expressed predominantly m2 (10.31 +/- 0.43 pg mRNA/micrograms total RNA) and some m1 (1.54 +/- 0.84 pg/microgram) muscarinic receptor mRNA, which increased developmentally to adult levels (m2 mRNA levels being 60% higher than those in neonates). By contrast, m3, m4, and m5 subtype mRNAs were much less abundant at all time points measured. A similar developmental regulation was found in dissociated SCG neurons in vitro. After 16 days in culture, m2 mRNA increased 334% to 15.76 +/- 0.68 pg/microgram, while m1 mRNA changed little (2.03 +/- 1.00 pg/microgram). However, LIF or CNTF treatment (5 ng/ml, 14 days) in sister cultures completely blocked this developmental increase. Further, LIF treatment blocked the normal muscarinic receptor-mediated increase in intracellular calcium (fura-2 imaging), indicating a functional change in receptor phenotype. By contrast, levels of SPR mRNA, which were low in untreated cultures (0.037 +/- 0.025 pg SPR mRNA/microgram total RNA), were elevated by LIF or CNTF treatment, to 0.866 +/- 0.034 pg/microgram and 0.662 +/- 0.148 pg/microgram, respectively. These observations indicate that muscarinic and SPR receptor expression are differentially regulated by the same factors in SCG neurons and that neuronal choice of receptor phenotype may be, at least in part, specifically regulated by cytokines/growth factors in the cellular milieu.

Animals↗
PubMed1994

Transfer of the nerve growth factor gene into cell lines and cultured neurons using a defective herpes simplex virus vector. Transfer of the NGF gene into cells by a HSV-1 vector.

Nerve growth factor (NGF) can be expressed in cells by gene transfer using a defective Herpes Simplex virus type 1 (HSV-1) vector. In this report, the defective HSV-1 vector, pHSVngf, is used to infect established cell lines and cultured neurons. Infection of cell lines with pHSVngf results in gene transcription, correct RNA processing, and production of biologically active NGF. Infection of the PC12 neuronal cell line results in the production of biologically active NGF and infection of NGF-dependent neonatal sympathetic neurons in primary culture with pHSVngf leads to neuronal survival in the absence of exogenously-added NGF. NGF expressed by pHSVngf-infected cells does not appear to work through an autocrine intracellular pathway since NGF antibody added to culture media of infected cells could block NGF action. Infection with pHSVngf of cholinergic striatal or septal neurons in dissociated cell culture resulted in an increase in choline acetyltransferase activity. These studies demonstrate the efficacy of defective HSV-1 vectors for delivery and expression of neurotrophin genes in cultured neural cells.

3T3 Cells↗
PubMed1994

Neutralization of primary human immunodeficiency virus type 1 isolates by the broadly reactive anti-V3 monoclonal antibody, 447-52D.

Human monoclonal antibody 447-52D binds to the V3 determinant of the human immunodeficiency virus type 1 (HIV-1) gp120 external glycoprotein. Its binding requires the expression of the GPxR sequence at the center of the V3 domain. HIV-1 variants that are adapted to replication in T-lymphoid cell lines and express this sequence motif are efficiently neutralized by the antibody (M. K. Gorny, A. J. Conley, S. Karwowska, A. Buchbinder, J.-Y. Xu, E. A. Emini, S. Koenig, and S. Zolla-Pazner, J. Virol. 66:7538-7542, 1992). In the present study, the antiviral activity of 447-52D was further defined with regard to its ability to mediate neutralization of primary HIV-1 clinical isolates. Again, the antibody was found to potently neutralize those isolates that expressed the binding sequence. We confirmed that this determinant is commonly expressed by virus isolates belonging to the subtype (clade) B sequence classification. As such, 447-52D may be useful for prophylactic and immunotherapeutic intervention. In addition, the study demonstrated that neutralization of primary HIV-1 isolates is possible if mediated by an appropriate antibody.

AIDS Vaccines↗
PubMed1994

Growth factor regulation of neuronal development.

Recent experimental investigations have redefined the spectrum of growth factors and developmental signalling pathways that are necessary to orchestrate the growth and differentiation of regional neuronal subpopulations. Gene knockout studies of the classic neurotrophins and their high-affinity tyrosine kinase (Trk) receptors have refined our definition of the cellular mechanisms and target populations of these neuronotrophic factors. Recognition of the significant parallels that exist between neuropoiesis and hematolymphopoiesis has fostered our study of the range and cellular actions of these hemopoietins in neuronal development. In addition, by activating receptor subunits that possess serine/threonine activity, bone morphogenetic proteins of the transforming growth factor-beta superfamily exhibit complex spatiotemporal regulation of regional neuronal subpopulations. These collective observations suggest that a complex hierarchy of epigenetic signals is required for the growth and maturation of regional neuronal lineage species in the central and peripheral mammalian nervous system.

Animals↗
PubMed1994

Superoxide dismutase ameliorates neuronal death from hypoxia in culture.

BACKGROUND AND PURPOSE: Studies showing efficacy with free radical scavengers have been conflicting, and when protection was demonstrated it was attributed to action at the level of the vascular endothelium. The purpose of this study was to test the hypotheses that neuronal free radical formation plays a role in the ischemic cascade and occurs intracellularly and that free radical scavengers, if taken up intracellularly, will protect against hypoxic damage. METHODS: A tissue culture model of hypoxia followed by restoration of oxygen was employed, using both superior cervical ganglia and hippocampal neurons. Cells were exposed to an anoxic atmosphere of 95% N2 and 5% CO2 and examined 2 to 24 hours later after restoration of oxygen. Determination of survival was measured by trypan blue exclusion. Nitroblue tetrazolium stain was used to assess free radical formation. RESULTS: Pretreatment with free superoxide dismutase did not decrease cell death after hypoxia as measured by trypan blue exclusion. However, when superoxide dismutase was taken up intracellularly under depolarizing conditions (55 mmol/L KCl in the medium), cell death was decreased significantly compared with hypoxic controls (28.7 +/- 4.34 versus 40.3 +/- 4.33; P < .03). During hypoxia neurons reduced nitroblue tetrazolium to form the blue precipitate formazan, and the color change was blocked in neurons pretreated with superoxide dismutase in depolarizing medium. Similar findings occurred in both superior cervical ganglia and hippocampal neurons. CONCLUSIONS: These findings provide evidence to support the role of neuronal free radical formation in cell death secondary to hypoxia. In addition, free radical scavengers, if taken up intracellularly, may partially ameliorate their deleterious effect.

Animals↗
PubMed1993

Cell density regulates neuropeptide Y expression in cultured sympathetic neurons.

Neurotransmitters and neuropeptides coexpressed by the same neuron may be regulated independently. The peptide transmitter, neuropeptide Y (NPY), has been identified in approximately 60% of rat sympathetic superior cervical ganglion (SCG) neurons, virtually all of which are catecholaminergic. However, we find that environmental signals which affect noradrenergic traits in cultured rat SCG, regulate NPY expression differently. Relatively large increases in neuronal density only slightly alter catecholaminergic properties in sympathetic neurons. However, levels of NPY were highly dependent on cell density. In pure neuronal cultures, increasing cell numbers from 8000 to 12,000 neurons per culture resulted in a 10-fold decrease in NPY. Coculture of SCG neurons with ganglion nonneuronal cells further reduced NPY levels at all neuronal densities examined. Treatment with the neuropoetic cytokine, leukemia inhibitory factor, which increased the expression of cholinergic traits and decreased noradrenergic expression, decreased NPY by 50% in cocultures. Finally, neither glucocorticoids nor the cytokine interleukin-1 beta, which regulate other transmitter systems, altered NPY expression. These observations indicate that although noradrenergic traits and NPY are often coexpressed, they are regulated independently in SCG neurons. Further, expression of NPY is highly influenced by cell-cell contact.

Animals↗
PubMed1993

Cytokine regulation of neuronal differentiation of hippocampal progenitor cells.

The signalling mechanisms governing haematolymphopoiesis and those regulating neural development may be closely related, as indicated by similarities of higher-order structure and function of the cytokines involved, of the regional and temporal regulation of their transcription and translation, and of their bioactivity. Here we investigate this possible evolutionary connection using retroviral transduction of a temperature-sensitive mutant form of the SV40 large T antigen to develop conditionally immortalized murine embryonic hippocampal progenitor cell lines. Treatment of these cells with cytokines that are thought to participate in progressive lymphoid maturation, immunoglobulin synthesis and erythropoiesis causes progressive neuronal differentiation, as defined by morphological criteria, successive expression of increasingly mature neurofilament protein, and the generation of inward currents and action potentials. The cytokine interleukin(IL)-11 induces expression of action potentials that are insensitive to tetrodotoxin, which is indicative of developmentally immature sodium channels. By contrast, for expression of more mature action potentials (tetrodotoxin-sensitive) one of the interleukins IL-5, IL-7 or IL-9 must be applied in association with transforming growth factor-alpha after pretreatment with basic fibroblast growth factor. Our results suggest that the mechanisms regulating lineage commitment and cellular differentiation in the neural and haematopoietic systems are similar. Further, they define an in vitro model system that may facilitate molecular analysis of graded stages of mammalian neuronal differentiation.

Action Potentials↗
PubMed1993

Effects of administration of ciliary neurotrophic factor on normal motor and sensory peripheral nerves in vivo.

Ciliary neurotrophic factor (CNTF) has a variety of effects on different neuronal populations in vitro, but little has been reported concerning its effects in vivo. This study examined the effects of CNTF administration on peripheral nerves both in young growing rats and in more mature animals. In both young and fully grown rats, CNTF stimulated levels of substance P and calcitonin gene related peptide in sensory spinal ganglia. In immature rats, CNTF increased compound nerve conduction velocity and motor nerve conduction velocity. By contrast, electrophysiological measurements were not affected in fully grown animals. There was a biphasic dose response to CNTF for the electrophysiologic changes with larger changes noted at a dose of 0.1 micrograms/g body weight than at a dose of 0.25 micrograms/g. There were no behavioral changes noted at either dose of the factor. These observations indicate that CNTF administration in vivo can influence neural physiology, and suggest that the factor may be useful for the treatment of disorders involving either sensory or motor peripheral nerves.

Aging↗
PubMed1993

Leukemia inhibitory factor and ciliary neurotrophic factor regulate expression of muscarinic receptors in cultured sympathetic neurons.

Regulation of muscarinic receptor expression was studied in cultured sympathetic neurons of the neonatal rat superior cervical ganglion (SCG). Leukemia inhibitory factor (LIF) and ciliary neurotrophic factor (CNTF), both previously shown to regulate neurotransmitter development in cultured SCG neurons (Yamamori et al., 1989; Saadat et al., 1989), were examined for effects on receptor expression. Exposure of SCG neurons to LIF or CNTF (5 ng/ml) prevented the normal developmental increase in muscarinic receptors as measured by whole cell binding of N-methyl[3H]scopolamine. Reduction in receptor binding was detected within 2 to 4 days of treatment, with a 65-80% reduction after 16 days. Scatchard analysis demonstrated a reduction in total receptor number (Bmax) with no significant change in receptor affinity (Kd). Concentrations of 1 ng/ml of either factor reduced receptor expression with near-maximal effectiveness at doses of 10 ng/ml. The decrease in muscarinic receptors was not blocked by atropine, indicating that it was not agonist induced. Treatment with LIF or CNTF did not affect the survival of cultured neurons. Further, effects on receptor expression were reversible after discontinuance of treatment. Finally, treatment with either factor increased overall protein synthesis, indicating the integrity of cellular metabolism of cultures and hence the specificity of the decrease in muscarinic receptor number. LIF and CNTF thus regulate receptor as well as neurotransmitter development and could therefore play a role during synaptogenesis in the developing nervous system.

Animals↗
PubMed1993

Cytokine-induced programmed death of cultured sympathetic neurons.

Programmed cell death (PCD) of sympathetic neurons is inhibited by nerve growth factor. However, factors that induce PCD of these cells are unknown. Leukemia inhibitory factor (LIF) and ciliary neurotrophic factor, neuropoietic cytokines known to regulate sympathetic neuron gene expression, were examined for effects on survival of cultured sympathetic neurons. Treatment with LIF or ciliary neurotrophic factor caused neuronal death in a dose-dependent fashion. Inhibition of RNA or protein synthesis, or treatment with potassium, all of which prevent PCD after nerve growth factor deprivation, prevented LIF-induced death. The morphologic and ultrastructural characteristics of the neuronal death induced by LIF and by nerve growth factor deprivation were similar. Furthermore, LIF treatment resulted in DNA fragmentation with a characteristic "ladder" on Southern blot analysis. These observations suggest that neuron numbers may be regulated by factors which initiate PCD, as well as by factors which prevent it.

Analysis of Variance↗