Lysosomal ceroid depletion by drugs: therapeutic implications for a hereditary neurodegenerative disease of childhood.

Neuronal ceroid lipofuscinoses (NCLs) are the most common hereditary neurodegenerative diseases of childhood. The infantile form, INCL, is caused by lysosomal palmitoyl-protein thioesterase (PPT) deficiency, which impairs the cleavage of thioester linkages in palmitoylated proteins, preventing their hydrolysis by lysosomal proteinases. Consequent accumulation of these lipid-modified proteins (constituents of ceroid) in lysosomes leads to INCL. Because thioester linkages are susceptible to nucleophilic attack, drugs with this property may have therapeutic potential for INCL. We report here that two such drugs, phosphocysteamine and N-acetylcysteine, disrupt thioester linkages in a model thioester compound, [14C]palmitoyl approximately CoA. Most importantly, in lymphoblasts derived from INCL patients, phosphocysteamine, a known lysosomotrophic drug, mediates the depletion of lysosomal ceroids, prevents their re-accumulation and inhibits apoptosis. Our results define a novel pharmacological approach to lysosomal ceroid depletion and raise the possibility that nucleophilic drugs such as phosphocysteamine hold therapeutic potential for INCL.

Influence of a radioprotector WR-638 on the lymphoid compartment of the irradiated rat thymus: a flow cytometric analysis.

The T cell composition of the thymus of X-ray irradiated (3.5 Gy) Wistar rat protected with WR-638 was analyzed by flow cytometry using monoclonal antibodies directed to the Thy 1.1, CD43, CD2, CD5, CD4, CD8 and class I and II MHC antigens. It was shown that this dose of X-rays caused cyclic changes in thymic cellularity manifested as: primary involution (until day 2), primary regeneration (from days 2 to 14), secondary involution (from days 14 to 21) and secondary regeneration (from days 21 to 30). WR-638 reduced the magnitude of thymocyte depletion in the primary involutive phase of the irradiated thymi, primarily as a result of protection of Thy 1.1high+ CD2low+ CD5high+ CD4+ CD8+ class I antigen high+ subpopulations of thymocytes. In the early regenerative phase, WR-638 accelerated the regeneration of CD4-CD8- and CD4-CD8+ thymocyte subsets, followed by subsequent increase of CD4+CD8+ and CD4+CD8- thymocyte subsets. Secondary involutive and regenerative phases in protected animals were characterized by higher absolute cell number of almost all thymocyte subpopulations in comparison with those in irradiated, non-protected animals.

[Radioprotective and therapeutic modulation of thymus gland regeneration in rats after x-ray irradiation]. / Radioprotektivna i terapijska modulacija regeneracije timusa pacova nakon X-zracenja.

There have been studied effects of cystaphos, gammaphos, hydroxyurea, polyadenyl-polyuridinic acids (poly A:poly U) as well as the combination of gammaphos and poly A:poly U, that is, cystaphos and superoxide dismutase on the thymus of Wistar and AO rats irradiated by the hard X-rays in the dose of 5 or 3.5 Gy. Changes were observed up to 30 days after irradiation. The most efficacious protective effect has shown cystaphos (358 mg/kg i.p. 20 min. after irradiation) in Wistar rats irradiated by the dose of 3.5 Gy. It lowered involutive changes and accelerated thymus regeneration. On the basis of phenotypic analysis of thymocytes it can be supposed that such a favourable effect is the consequence of a larger protection of the cortical (strong OX 7+) thymocytes. Differing from cystaphos, transplantation of the syngeneic cells of the bone marrow in AO rats irradiated by the dose of 5 Gy showed favourable effect on thymus regeneration in later phase after irradiation preventing secondary thymus involution.

[The effect of phenol derivatives on the antimutagenic activity of dextran]. / Vliianie proizvodnykh fenola na antimutagennuiu aktivnost' dekstrana.

The effects of dextran + hydrazine or amino derivative of dibunol and of dextran + cystafos derivatives with different degree of modification of their molecules on the mutagenic activity of gamma irradiation were studied using the micronucleus test in polychromatophilic erythrocytes of the mouse bone marrow. The effects of these compounds on differentiation of the erythroid series has also been studied. The mutagenic activity of gamma irradiation was most markedly inhibited by the copolymer dextran and the amino derivative dibunol. The optimal structure of copolymers was 1 heterocyclic link per 3 non-oxidized links of dextran, while the increasing number of active links in the dextran molecule insignificantly enhanced its antimutagenic effect. The studied compounds effectively protected erythropoiesis.

[The antimutagenic activity of compounds of modified polyglucin]. / Antimutagennaia aktivnost' soedinenii modifitsirovannogo poligliukina.

The effect of modified polygluquin compounds on gamma-irradiated nuclei of V-79 Chinese hamster cells has been studied. Antimutagenic properties of the compounds are determined by aldehyde groups and oxidized chains.

[Stimulating effect of aminoethylisothiuronium on the immune response and interferonogenesis in irradiated mice]. / Stimuliruiushches deistvie aminoétilizotiuroniia na immune reaktsii i interferonogenez u obluchennykh myshei.

Aminoethylisothiuronium (AET) stimulated the formation of antibodies against sheep erythrocytes, not against E. coli, in X-irradiated (4 Gy) mice. The serum containing AET-induced interferon had the same effect. AET also promoted the rejection of the allogenic skin graft in mice irradiated with the same dose. In addition, AET and cystaphos stimulated the induction of interferon by the Newcastle disease virus in mice exposed to doses of 4, 5 or 6 Gy.

[Modelling modification of chemical mutagenesis in human cells. III. Linear index of protection as the standardized criterion of modification]. / Modelirovanie modifikatsii khimicheskogo mutageneza v kletkakh cheloveka. Soobshchenie III. Lineinyi pokazatel' zashchity--unifitsirovannyi kriterii modifikatsii.

The effect of substances with radioprotective activity, APAETP 2,3 (aminopropylaminoethylthiophosphoric acid 2,3), APAETP 3,3 and cystaphos, on chromosome aberrations, induced by thioTEPA in the culture of human lymphocytes was investigated. It is shown that the obtained curves "concentration -- effect" for thioTEPA can be described by equations rho = 1 -- e-(KC + alpha)2 and X = E -(KC + alpha)2 --1 for aberrant cells and for chromosome breaks in the presence of the investigated substances. On the basis of comparison of angle coefficients of regression the unificated characteristic of the efficiency of chemical mutagenesis is proposed: the linear protection index (LPI), with generalizes the effect of modificators in chemical mutagenesis.

Time dependence of radioprotective effects of A. flavus conidia.

No essential difference in radioprotection results when conidia of A. flavus are applied to mice within a time lapse of a few minutes up to 48 hours prior to irradiation. When applied 72 hr before irradiation, they fail to affect mouse resistance. Application of conidia provide no protection to mice irradiated for 18-20 hr at the dose rate of 1 R/min; similarly ineffective are the chemoprotectors cistafos and mexamine. A combined administration of conidia and the two protective substances increases survival in mice and prolongs the mean survival period.

[Study of the cytogenetic activity of radioprotective agents in a human lymphocye culture. III]. / Izuchenie tsitogeneticheskoi aktivnosti radioprotektorov v kul'ture limfotsitov cheloveka. Soobshchenie III

Distribution of chromosome aberrations in cells of human lymphocyte cultures treated with mutagenic agent thioTEPA and protectors--aminopropylaminoethyl thiophosphoric acid (grammaphos) cystaphos and 5-metoxytriptamine (mexamine) was studied. It is shown that the empirical distribution of aberrations in cell is described by geometrical distribution.

[Study of the cytogenetic activity of radioprotectors in a human lymphocyte culture. II]. / Izuchenie tsitogeneticheskoi aktivnosti radioprotektorov v kul'ture limfotsitov cheloveka. Soobshchenie II

Action of certain radioprotectors: 2-mercaptoethylamine HCl (MEA), cysteine HCl, 2-aminoethylsothiouronium (AET), dithiol 2,3-dimercaptopropansulphate Na (unithiol), aminopropylaminoethylthiophosphoric acid (gammaphos), cystaphos and 5-metoxytriptamine (mexamine) was studied as applied to human chromosome aberrations induced with thio-TEPA. It was shown that with an increase in thioTEPA and protectors concentrations their effect grows.

[Dynamics of production and various properties of interferon-like inhibitors formed under the influence of AET and cystaphos in vivo and in cell cultures]. / Dinamika vyrabotki i nekotorye svoistva interferonopodobnykh ingibitorov, obrazuiushchikhsia pod vliianiem AET i tsistafosa v organizme i kletochnykh kul'turakh

Interferon-like virus inhibitors appeared in the blood serum of animals and in the culture fluid 15 min.--1 hour and 4-6 hours after administration of AET (S, beta-amino-ethylisotiuronium) and cystaphos (monosodium salt of beta-aminoethylthiophosphorus acid). These inhibitors showed species-specificity, were inactivated by trypsin and by heating at 37 degrees C for 2 hours and at 56 degrees C for 1 hour, did not sediment at 100,000 g. It is assumed that these are two different inhibitors of which the one forming the early peak pre-exists in the cell. It is probably associated with cell membranes and is released as a result of chemical effect of aminothyols. The late peak of inhibitor is synthesized de novo as inducated by its sensitivity to the effect of puromycin and cycloheximide.