Gene therapy on demand: Site specific regulation of gene therapy

Since 1990 when the first clinical gene therapy trial was conducted, much attention and considerable promise have been given to this form of treatment. Gene therapy has been used with success in patients suffering from severe combined immunodeficiency syndromes (X-SCID and ADA-deficiency), Leber's congenital amaurosis, hemophilia, β-thalassemia and adrenoleukodystrophy. Last year, the first therapeutic vector (Glybera) for treatment of lipoprotein lipase deficiency has been registered in the European Union. Nevertheless, there are still several numerous issues that need to be improved to make this technique more safe, effective and easily accessible for patients.     

Relationship between autoantibodies to erythropoietin receptor and renal outcome in patients with anti-neutrophil cytoplasmic antibody-associated vasculitis

Abstract

Purpose: We examined the relationship between autoantibodies to erythropoietin receptor (EPOR) and renal outcome in patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV).

Materials and methods: Sixty-three Japanese patients with AAV were enrolled and followed for a median of 31.4?months. Patients were screened for serum anti-EPOR antibodies using an enzyme-linked immunosorbent assay. Associations of anti-EPOR antibodies with clinical parameters were analyzed using logistic-regression models.

Results: Anti-EPOR antibodies were detected in 7 (11%) of the 63 patients, and levels of the antibodies decreased with immunosuppressive therapy. The presence of anti-EPOR antibodies was associated with a higher Birmingham vasculitis activity score. In addition, anti-EPOR antibodies were more frequently observed in patients with renal outcomes, which was defined as a sustained 50% reduction in the estimated glomerular filtration rate from baseline, than in those without. Multiple logistic regression analysis revealed that presence of anti-EPOR antibodies, as well as age at disease onset, were as risk factors for the renal outcome.

Conclusion: Anti-EPOR antibodies were associated with the progression of renal dysfunction in patients with AAV.     

Longer action means better drug: tuning up protein therapeutics

An increasing number of proteins are currently available on the market as therapeutics and this branch of the pharmaceutical industry will expand substantially during the coming years. As many diseases result from dysfunction of proteins forming multicomponent complexes, protein drugs with their inherent high specificity and affinity seem to be optimal medical agents. On the other hand, proteins are often highly instable and sensitive to degradation, which questions their applicability as effective therapeutics. Therefore, redesign and engineering of proteins is usually a required step in the present day drug development.Several approaches have been applied to optimize the protein properties central to their pharmaceutical use. This review focuses on different strategies that improve two crucial factors influencing protein drug efficiency: protein stability and its in vivo half-life. We provide examples of successful genetic and chemical modifications applied in the design of effective protein therapeutics.     

Akt activation through the phosphorylation of erythropoietin receptor at tyrosine 479 is required for myeloproliferative disorder-associated JAK2 V617F mutant-induced cellular transformation

The disruption of Janus kinase 2 (JAK2) signaling regulation by its point mutation, V617F, is involved in various myeloproliferative disorders (MPDs). JAK2 V617F mutant induced constitutive activation of Akt when erythropoietin receptor (EpoR) was coexpressed; however, the physiological role of Akt activation in MPDs has not been elucidated. LY294002, a phosphoinositide 3-kinase (PI3K) inhibitor, inhibited Akt activation and induced apoptotic cell death in cells expressing JAK2 V617F mutant and EpoR. Previously, it has been shown that the phosphorylation at Y479 in EpoR is critical for the interaction with PI3K, an upstream molecule of Akt. Hence, EpoR mutant with a point mutation of Y479F, which fails to activate Akt, is useful for addressing the role of Akt activation in JAK2 V617F mutant-induced tumorigenesis. Interestingly, under the expression of EpoR Y479F mutant, JAK2 V617F mutant failed to exhibit potent anti-apoptotic activity. In addition, JAK2 V617F mutant-induced phosphorylation of CREB and GSK-3β was significantly decreased in cells expressing EpoR Y479F mutant, resulting in the downregulation of Bcl-XL and Mcl-1 expression. Furthermore, compared with when nude mice were inoculated with cells expressing JAK2 V617F mutant and EpoR, the lifespan of nude mice inoculated with cells expressing JAK2 V617F mutant and EpoR Y479F mutant was effectively prolonged. Taken together, it was clarified that PI3K-Akt activation through the phosphorylation of EpoR at Y479 is required for oncogenic signaling of JAK2 V617F mutant and that targeted disruption of this pathway has therapeutic utility.     

Heat shock protein 70 inhibits the nuclear import of apoptosis-inducing factor to avoid DNA fragmentation in TF-1 cells during erythropoiesis

Loss of mitochondrial membrane potential (DeltaPsi(m)) and release of AIF (apoptosis-inducing factor) from mitochondria are key steps in apoptosis. In TF-1 model, DeltaPsi(m) was depolarized with AIF release during erythroid development. Yet, no DNA fragmentation was observed. When DeltaPsi(m) depolarization had been blocked, erythropoiesis was suppressed. Interestingly, heat shock protein 70 (Hsp70) was found transiently upregulated during depolarization and it retained AIF in the cytosol to avoid DNA damages. When Hsp inhibitor was added, DNA fragmentation occurred. We show this mechanism for the first time in erythropoiesis how cells with DeltaPsi(m) depolarization and AIF release escape apoptosis.     

重组人促红细胞生成素在国内外药典中质量标准不同点的对比分析

目的:对比重组人促红细胞生成素在《欧洲药典》(第5版)和《中国药典》(2005年版)中标准的不同点,为国内研发机构对基因重组蛋白产品的研发及国内企业对该产品的进出口提供参考。方法:按2部药典要求,对进口产品或国产产品实样进行部分关键指标的对比分析。结果:2部药典对该产品的标准描述上存在具体内容的区别。结论:在现代药物的研发和生产中,对药品的国际及国内标准要进行综合分析而拟定。     

Erythroid differentiation is augmented in Reelin-deficient K562 cells and homozygous reeler mice

Reelin is an extracellular glycoprotein that is highly conserved in mammals. In addition to its expression in the nervous system, Reelin is present in erythroid cells but its function there is unknown. We report in this study that Reelin is up-regulated during erythroid differentiation of human erythroleukemic K562 cells and is expressed in the erythroid progenitors of murine bone marrow. Reelin deficiency promotes erythroid differentiation of K562 cells and augments erythroid production in murine bone marrow. In accordance with these findings, Reelin deficiency attenuates AKT phosphorylation of the Ter119⁺CD71⁺ erythroid progenitors and alters the cell number and frequency of the progenitors at different erythroid differentiation stages. A regulatory role of Reelin in erythroid differentiation is thus defined.     

重组人红细胞生成素在妇科围手术期贫血治疗中的应用研究现状

抗对于妇科围手术期患者,由于术前贫血、术中失血或术后炎症,可能导致贫血状况愈加严重,而旨在改善患者预后和减少异体输血的妇科围手术期血液管理措施越来越被重视。重组人红细胞生成素能显著升高贫血患者血红蛋白水平并减少输血需求,其应用于围手术期贫血的纠正,已成为临床研究的新热点。综述重组人红细胞生成素治疗妇科围手术期贫血的作用机制、国内外临床研究及安全性研究。