Immune function in cyclophosphamide-treated mice is restored by the T-cell-tropic isoxazole derivative R-13

Synthesis of 4-Aryl-1,3,4-benzotriazepinones from Isatoic Anhydrides and Hydrazonyl Chlorides

An efficient synthesis of 4-aryl-1,3,4-benzotriazepinones from readily available isatoic anhydrides and hydrazonyl chlorides was developed. In this facile protocol, a series of functionalized 1,3,4-benzotriazepinones were conveniently obtained with broad substrate scope and excellent functional group tolerance.

Isoxazole Derivatives as Regulators of Immune Functions

In this review, we present reports on the immunoregulatory properties of isoxazole derivatives classified into several categories, such as immunosuppressive, anti-inflammatory, immunoregulatory, and immunostimulatory compounds. The compounds were tested in various models using resident cells from rodents and humans, cell lines, and experimental animal disease models corresponding to human clinical situations. Beneficial features of the described isoxazole derivatives include low toxicity and good bioactivity at low doses. In a majority of studies, the activities of investigated compounds were comparable or even higher than registered reference drugs. Whenever possible, a plausible mechanism of action of the investigated compounds and their potential therapeutic utility were proposed. Among the described compounds, particular attention was paid to the class of immune stimulators with a potential application in chemotherapy patients.

Synthesis, Immunosuppressive Properties, and Mechanism of Action of a New Isoxazole Derivative

This work describes the synthesis of a new series of isoxazole derivatives, their immunosuppressive properties, and the mechanism of action of a representative compound. A new series of N′-substituted derivatives of 5-amino-N,3-dimethyl-1,2-oxazole-4-carbohydrazide (MM1⁻MM10) was synthesized in reaction of 5-amino-N,3-dimethyl-1,2-oxazole-4-carbohydrazide with relevant carbonyl compounds. The isoxazole derivatives were tested in several in vitro models using human cells. The compounds inhibited phytohemagglutinin A (PHA)-induced proliferation of peripheral blood mononuclear cells (PBMCs) to various degrees. The toxicity of the compounds with regard to a reference A549 cell line was also differential. 5-amino-N′-(2,4-dihydroxyphenyl)methylidene-N,3-dimethyl-1,2-oxazole-4-carbohydrazide (MM3) compound was selected for further investigation because of its lack of toxicity and because it had the strongest antiproliferative activity. The compound was shown to inhibit lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF α) production in human whole blood cell cultures. In the model of Jurkat cells, MM3 elicited strong increases in the expression of caspases, Fas, and NF-κB1, indicating that a proapoptotic action may account for its immunosuppressive action in the studied models.

Effect of Cyclophosphamide Treatment on Central and Effector Memory T Cells in Mice

Immunological memory is a key feature of adaptive immunity. It provides the organism with long-lived and robust protection against infection. The important question is whether cyclophosphamide (CP), as immunosuppressive agent used in cancer therapy and in some autoimmune diseases, may act on the memory T-cell population. We investigated the effect of CP on the percentage of central memory T cells (T_CM) and effector memory T cells (T_EM) in the mouse model of CP-induced immunosuppression (8-10-week-old male C57BL/6 mice CP treated for 7 days at the daily dose of 50 μg/g body weight [bw], manifested the best immunosuppression status, as compared to lower doses of CP: 10 or 20 μg/g bw). The CP induced a significant decrease in the percentage of CD8⁺ (T_CM), compared to nonimmunosuppressed mice. This effect was not observed in the case of CD4⁺ T_CM population. The percentage of gated T_EM with CD4 and CD8 phenotype was significantly decreased in CP-treated mice, as compared to the control ones. Taken together, the above data indicate that CP-induced immunosuppression in mice leads to a reduction in the abundance of central memory cells possessing preferentially CD8⁺ phenotype as well as to a reduction in the percentage of effector memory cells (splenocytes both CD4⁺ and CD8⁺), compared to the cells from nonimmunosuppressed mice. These findings in mice described in this article may contribute to the understanding of the complexity of the immunological responses in humans and extend research on the impact of the CP model of immunosuppression in mice and memory T-cell populations.

Anti-inflammatory properties of an isoxazole derivative - MZO-2

BACKGROUND

A series of new isoxazole derivatives of expected immunosuppressive activities was synthesized. Following in vitro screening in the human cell models, the activity of MZO-2 compound (ethyl N-{4-[(2,4-dimethoxybenzyl)carbamoyl]-3-methylisoxazol-5-yl}acetimidate) in mouse in vivo models was evaluated.

METHODS

In vitro tests included evaluation of: peripheral blood mononuclear cells (PBMC) viability, phytohemagglutinin (PHA)-induced PBMC proliferation and lipopolysaccharide (LPS)-induced tumor necrosis factor α (TNF α) production in whole blood cell cultures. MZO-2 was studied in mice for its effects on: humoral immune response to sheep erythrocytes (SRBC), delayed type hypersensitivity (DTH) to ovalbumin (OVA), contact sensitivity to oxazolone and carrageenan-induced foot pad edema. In addition, the effect of MZO-2 on expression of caspases in Jurkat cells was determined.

RESULTS

The studied compounds exhibited differential, dose-dependent effects to suppress PHA-induced PBMC proliferation and a weak property to suppress LPS-induced production of TNF α. MZO-2 had no effect on the induction phase of the humoral immune response to SRBC in vitro and in vivo, but moderately suppressed the induction phase of DTH to OVA. Its inhibitory effect on carrageenan-induced paw inflammation was potent. Likewise, MZO-2, applied in ointment, was very effective in reducing ear edema and number of lymphocytes in draining lymph nodes of mice sensitized to oxazolone, comparably to tacrolimus, the reference drug. The expression of caspases 3, 8 and 9 in Jurkat cells was inhibited by the compound.

CONCLUSION

MZO-2, applied systemically or locally, may serve as a potential drug for amelioration of inflammatory processes.