Advances of the novel immunosuppressant brasilicardin A / 生物工程学报

Brasilicardin A (BraA) is a natural diterpene glycoside isolated from the pathogenic actinomycete Nocardia brasiliensis IFM 0406 with highly potent immunosuppressive activity (IC50=0.057 μg/mL). BraA potently inhibits the uptake of amino acids that are substrates for amino acid transport system L of T cells, which is different from the existing clinical immunosuppressants. BraA is more potent in a mouse mixed lymphocyte reaction and less toxic against various human cell lines compared with the known clinical immunosuppressants, such as cyclosporin A, ascomycin and tacrolimus. Therefore, BraA attracted more attention as a new promising immunosuppressant. However, the development of this promising immunosuppressant as drug for medical use is so far hindered because BraA has the unusual and synthetically challenging skeleton and shows the low-yield production in the natural pathogenic producer. This review introduces the molecular structure of BraA, its activity, mechanism of action, chemical synthesis of BraA analogs, heterologous expression of gene cluster, and an application of combining microbial and chemical synthesis for production of BraA, with the aim to facilitate the efficient production of BraA and its analogs.

Tuberculosis asociada a antagonistas del factor de necrosis tumoral alfa, presentación de un caso y análisis de los casos reportados en Colombia / Tuberculosis associated with tumor necrosis factor-α antagonists, case description and analysis of reported cases in Colombia

Resumen El factor de necrosis tumoral alfa (FNTα) es una citocina fundamental en la reacción inmunitaria frente al cáncer y a infecciones tales como la tuberculosis. Esta molécula también desempeña un papel fundamental en la patogenia de enfermedades complejas y de difícil tratamiento, como la artritis reumatoidea, la espondilitis anquilosante, la enfermedad de Crohn, la psoriasis y la colitis ulcerativa, condiciones que suelen requerir el uso de medicamentos que antagonizan la función del factor de necrosis tumoral alfa, el cual se ha relacionado con un incremento del riesgo de desarrollar tuberculosis, micosis y otras infecciones graves. Se reporta el caso de un hombre de 68 años de edad con diagnóstico de enfermedad de Crohn, a quien se le administró tratamiento con antagonistas del FNTα, debido a lo cual desarrolló tuberculosis diseminada. El diagnóstico se hizo con base en los hallazgos histológicos y mediante pruebas de biología molecular. Se discuten la presentación clínica y el manejo del caso, y se hace un análisis comparativo de los casos de tuberculosis asociados al tratamiento con antagonistas del FNTα reportados en Colombia durante los últimos diez años, con especial énfasisen la detección y el tratamiento de la tuberculosis latente.

Abstract Tumor necrosis factor-α (TNF-α) is an important fundamental cytokine during the immune response against cancer and infections such as tuberculosis. This molecule also plays a key pathogenic role in complex and difficult-to-treat diseases such as rheumatoid arthritis, ankylosing spondylitis, Crohn's disease, psoriasis and ulcerative colitis. The treatment of these diseases frequently needs TNF-αantagonists, which has been related to an increased risk of developing tuberculosis, mycoses, and other severe infections. We report the case of a 68-year-old man with Crohn's disease, who developed disseminated tuberculosis due to anti-TNF-α immunosuppressive therapy. The diagnosis was based on the histopathological findings and molecular biology assays. We discuss the clinical presentation and workup of this case, and we present a comparative analysis of tuberculosis cases associated with anti-TNF-α reported in Colombia during the last 10 years emphasizing on the diagnosis and treatment of latent tuberculosis.

Comparison of 1% cyclosporine eye drops in olive oil and in linseed oil to treat experimentally-induced keratoconjunctivitis sicca in rabbits / Comparação da ciclosporina 1% em óleo de oliva e óleo de linhaça no tratamento da ceratoconjuntivite seca experimentalmente induzida em coelhos

ABSTRACTPurpose:To evaluate the effectiveness of topical 1% cyclosporine eye drops diluted in either of the two vehicles-olive and linseed oil-and that of the oils themselves in treating experimentally-induced keratoconjunctivitis sicca (KCS) in rabbits.Methods:KCS was induced in 25 New Zealand rabbits using 1% atropine sulfate eye drops for 7 days before treatment and throughout the treatment period (12 weeks). The rabbits were divided into five groups: one control (C) group without KCS induction and four treatment groups in which KCS was induced and treated topically with olive oil (O), linseed oil (L), cyclosporine in olive oil (CO), and cyclosporine in linseed oil (CL). The animals were evaluated using Schirmer tear test 1 (STT), the fluorescein test (FT), tear-film break-up time (TBUT), the rose bengal test (RBT), and histopathological analysis.Results:Values of STT and TBUT significantly decreased 1 week post-induction (p<0.05) and were similar to initial values after the 4th week of treatment, in all groups. After KCS induction, there was significantly less corneal damage in group L than in group CL, as assessed FT and RBT. Histopathology demonstrated that Groups L and CL presented less edema and corneal congestion. There was no significant difference in the goblet cell density (cells/mm2) between the groups (p=0.147).Conclusion:Cyclosporine diluted in olive oil or linseed oil was effective in the treatment of KCS, although it had better efficacy when diluted in linseed oil. Linseed oil presented better effectiveness, whether associated or not, than olive oil. These results may contribute to the creation of novel topical ophthalmic formulations for KCS treatment in future.

RESUMOObjetivo:Avaliar a eficácia do uso tópico do colírio de ciclosporina 1% em dois veículos, óleo de oliva e linhaça, e dos óleos separados, no tratamento da ceratoconjuntivite seca experimentalmente induzida (KCS) em coelhos.Método:Vinte e cinco coelhos Nova Zelândia foram induzidos para KCS com colírio de sulfato de atropina a 1% por sete dias antes e durante o período de tratamento (12 semanas) e foram divididos em 5 grupos, um grupo controle (C), sem indução de KCS e quatro grupos de tratamento tópico com ciclosporina em óleo de oliva (CO), ciclosporina em óleo de linhaça (CL), óleo de oliva (O) e óleo de linhaça (L). Os animais foram avaliados utilizando o teste lacrimal de Schirmer I (STT), teste de fluoresceína (FT), teste de ruptura do filme lacrimal (TBUT), teste de rosa bengala (RBT) e análise histopatológica.Resultados:Os valores de TBUT e STT diminuíram significativamente uma semana pós-indução da KCS (p<0,05) e foram semelhantes aos valores iniciais após a quarta semana de tratamento, em todos os grupos. Após a indução de KCS, houve menor dano na córnea no grupo L em relação ao grupo CL, quando avaliados FT e RBT. A histopatologia demonstrou que os grupos L e CL apresentaram menos edema e congestão da córnea. Não houve diferença significativa na densidade das células caliciformes (células/mm2) entre os grupos (p=0,147).Conclusão:Ciclosporina diluída em óleo de oliva ou linhaça foi eficiente no tratamento da CCS, porém teve uma melhor eficácia quando diluída no óleo de linhaça. O óleo de linhaça, isoladamente ou associado, apresentou melhor eficácia quando comparado ao óleo de oliva. Estes resultados podem contribuir no futuro com novas formulações oftálmicas tópicas no tratamento da CCS.

Sirolimus: a new immunosuppressant.

Though organ transplantation has evolved in many a ways over the years, it is not without the disadvantage of causing rejections. Cyclosporin, azathioprine and corticosteroids are time tested and efficacious; however each is accompanied with its own array of disadvantages. Sirolimus is a relatively new immunosuppressant isolated from a macrolide antibiotic. It may have a beneficial role in prophylaxis of rejection as well as treatment of refractory rejection. It also has antifungal, antitumor and anti-smooth muscle proliferative roles.

Mechanism of the immunomodulatory activity of glycodelin.

Glycodelin, a progesterone regulated protein synthesized by the endometrium (GdA) has been well documented to inhibit the proliferation of activated T-cells and is an indispensable molecule in the maternal system for the establishment, maintenance and progression of pregnancy. Data from our laboratory have unequivocally shown that the immunosuppression by GdA is via induction of apoptosis in activated T cells. Another isoform of glycodein, GdS, from the male reproductive system, in spite of sharing an identical amino acid sequence as that of GdA has been shown not to harbour the immunosuppressive activity of GdA. As the only difference between the two proteins is glycosylation, we proposed to study the role of the sugars in imparting apoptotic activity to Gd. Using the recombinant baculovirus system, Gd lacking glycosylation was expressed and from the experimental observations we could conclude that the activity of Gd lies in the protein backbone. Recombinant Gd expressed in P. pastoris, and Chinese hamster ovary cells, like the GdS did not exhibit apoptotic activity. A close analyses of the glycans associated with the Gd molecules from various sources suggested that though the apoptogenic activity of Gd lies in the protein backbone, the glycans modulate the activity by masking (as in case of GdS and most recombinant Gd expressed in our laboratory) or unmasking (as in case of GdA and baculovirus expressed Gd), the functional region of the molecule.