Recombinant proteins in therapeutics: haemophilia treatment as an example

Fusion of a highly N-glycosylated polypeptide increases the expression of ER-localized proteins in plants

Plants represent promising systems for producing various recombinant proteins. One key area of focus for improving this technology is developing methods for producing recombinant proteins at high levels. Many methods have been developed to increase the transcript levels of recombinant genes. However, methods for increasing protein production involving steps downstream of transcription, including translation, have not been fully explored. Here, we investigated the effects of N-glycosylation on protein production and provide evidence that N-glycosylation greatly increases the expression levels of ER-targeted recombinant proteins. Fusion of the extracellular domain (M domain) of protein tyrosine phosphatase receptor type C (CD45), which contains four putative N-glycosylation sites to a model protein, leptin at the C-terminus, increased recombinant protein levels by 6.1 fold. This increase was specific to ER-targeted proteins and was dependent on N-glycosylation. Moreover, expression levels of leptin, leukemia inhibitory factor and GFP were also greatly increased by fusion of M domain at either the N or C-terminus. Furthermore, the increase in protein levels resulted from enhanced translation, but not transcription. Based on these results, we propose that fusing a small domain containing N-glycosylation sites to target proteins is a powerful technique for increasing the expression levels of recombinant proteins in plants.

Fusion of a highly N-glycosylated polypeptide increases the expression of ER-localized proteins in plants

Plants represent promising systems for producing various recombinant proteins. One key area of focus for improving this technology is developing methods for producing recombinant proteins at high levels. Many methods have been developed to increase the transcript levels of recombinant genes. However, methods for increasing protein production involving steps downstream of transcription, including translation, have not been fully explored. Here, we investigated the effects of N-glycosylation on protein production and provide evidence that N-glycosylation greatly increases the expression levels of ER-targeted recombinant proteins. Fusion of the extracellular domain (M domain) of protein tyrosine phosphatase receptor type C (CD45), which contains four putative N-glycosylation sites to a model protein, leptin at the C-terminus, increased recombinant protein levels by 6.1 fold. This increase was specific to ER-targeted proteins and was dependent on N-glycosylation. Moreover, expression levels of leptin, leukemia inhibitory factor and GFP were also greatly increased by fusion of M domain at either the N or C-terminus. Furthermore, the increase in protein levels resulted from enhanced translation, but not transcription. Based on these results, we propose that fusing a small domain containing N-glycosylation sites to target proteins is a powerful technique for increasing the expression levels of recombinant proteins in plants.

Hierarchical Design of Tissue Regenerative Constructs

The worldwide shortage of organs fosters significant advancements in regenerative therapies. Tissue engineering and regeneration aim to supply or repair organs or tissues by combining material scaffolds, biochemical signals, and cells. The greatest challenge entails the creation of a suitable implantable or injectable 3D macroenvironment and microenvironment to allow for ex vivo or in vivo cell-induced tissue formation. This review gives an overview of the essential components of tissue regenerating scaffolds, ranging from the molecular to the macroscopic scale in a hierarchical manner. Further, this review elaborates about recent pivotal technologies, such as photopatterning, electrospinning, 3D bioprinting, or the assembly of micrometer-scale building blocks, which enable the incorporation of local heterogeneities, similar to most native extracellular matrices. These methods are applied to mimic a vast number of different tissues, including cartilage, bone, nerves, muscle, heart, and blood vessels. Despite the tremendous progress that has been made in the last decade, it remains a hurdle to build biomaterial constructs in vitro or in vivo with a native-like structure and architecture, including spatiotemporal control of biofunctional domains and mechanical properties. New chemistries and assembly methods in water will be crucial to develop therapies that are clinically translatable and can evolve into organized and functional tissues.

The Socioeconomic Dimensions for the Management of Haemophilia in India

Purpose:

Haemophilia is an X-lined recessive disorder of coagulation that can affect any section of the society. Haemophilia is incurable and expensive lifelong disease; hence, the patient always brings in a financial crisis to manage its medication. In developing country like India the per capita health expenditure is 58 USD/year in 2012. The AHF therapy has been negligibly used in critical conditions of the disease. This study was undertaken to identify the social and economic dimensions that can influence the attitude of the medical practitioners for the choice of treatment therapy for a patient with haemophilia (PwH) in India.

Design/methodology/approach:

A cross-sectional study was conducted by collecting the primary data from the randomly selected 50 medical practitioners who were having at least one PwH on weekly basis. The EFA method was applied to determine the major socioeconomic dimensions of the choice of therapy.

Findings:

Four major dimensions were explored in the study that have significant impact on the attitude of medical practitioners. The availability of the AHF therapy is the most important dimension for consideration of a therapy for PwH in India. Moreover, the patient safety profile, patient affordability profile, and the experience of medical practitioners are three more dimensions that established the positive impact on attitude.

Research limitations/implications:

The methodology has socioeconomic tools for analysis and applied instrument has only 15 items for factor analysis.

Practical implications:

Governing bodies to rectify the policies on rare diseases because of inadequate supply of medicines. Academics would also benefit greatly since it will add value to existing body of literature on haemophilia in Indian context.

The use of an IL-1 receptor antagonist peptide to control inflammation in the treatment of corneal limbal epithelial stem cell deficiency

Corneal limbal stem cell deficiency (LSCD) may be treated using ex vivo limbal epithelial stem cells (LESCs) derived from cadaveric donor tissue. However, continuing challenges exist around tissue availability, inflammation, and transplant rejection. Lipopolysaccharide (LPS) or recombinant human IL-1β stimulated primary human keratocyte and LESC models were used to investigate the anti-inflammatory properties of a short chain, IL-1 receptor antagonist peptide for use in LESC sheet growth to control inflammation. The peptide was characterized using mass spectroscopy and high performance liquid chromatography. Peptide cytotoxicity, patterns of cell cytokine expression in response to LPS or IL-1β stimulation, and peptide suppression of this response were investigated by MTS/LDH assays, ELISA, and q-PCR. Cell differences in LPS stimulated toll-like receptor 4 expression were investigated using immunocytochemistry. A significant reduction in rIL-1β stimulated inflammatory cytokine production occurred following LESC and keratocyte incubation with anti-inflammatory peptide and in LPS stimulated IL-6 and IL-8 production following keratocyte incubation with peptide (1 mg/mL) (P < 0.05). LESCs produced no cytokine response to LPS stimulation and showed no TLR4 expression. The peptide supported LESC growth when adhered to a silicone hydrogel contact lens indicating potential use in improved LESC grafting through suppression of inflammation.

Medical Applications of Fermentation Technology

Fermentation, a process traditionally known for the anaerobic conversion of sugar to carbon dioxide and alcohol by yeast, now refers to an industrial process of manufacturing a wide variety of metabolites and biomaterials by using microorganisms or mammalian cells in a controlled culture environment. Fermentation can be performed in batch mode, continuous mode or in a combinatory, fed-batch mode, depending on the product of interest. Fermentation technology has long been known for the production of various medically important products such as antibiotics, solvents such as ethanol, intermediary compounds such as citric acid, probiotics such as yoghurt etc. New generation fermentation products include anti-viral drugs, therapeutic recombinant proteins and DNA, and monoclonal antibodies. Apart from the drugs, fermentation is also used for the commercial production of materials required for the development of diagnostic kits, drug delivery vehicles and medical devices. Fermentation technology remains at the heart of rapidly growing biopharmaceutical industry today, which is expected to expand even more in the days ahead, in parallel with the progress in novel, targeted drug discovery.

Gene therapy for haemophilia...yes, but...with non-viral vectors?

High-purity plasma-derived and recombinant factors are currently safe and efficient treatment for haemophilia. The mid-term future of haemophilia treatment will involve the use of modified recombinant factors to achieve advantages such as decreased immunogenicity in inhibitor formation and enhanced efficacy as a result of their longer half-life. In the long-term, gene therapy and cell therapy strategies will have to be considered. Achievements in cell therapy to date have been using embryonic stem cells and hepatic sinusoidal endothelial cells. Current gene therapy strategies for haemophilia are based on gene transfer using adeno-associated viruses and non-viral vectors. Gene therapy for haemophilia is justified because it is a chronic disease and because a very regular factor infusion is required that may involve fatal risks and because it is very expensive. Haemophilia is a very good candidate for use of gene therapy protocols because it is a monogenic disease, and even low expression is able to achieve reversion from a severe to a moderate phenotype. The current trends in haemophilia using adeno-associated viral vectors are safe but also involve immunogenicity problems. The other alternatives are non-viral vectors. There have been in recent years relevant advances in non-viral transfection that raise hope for considering this possibility. Several research groups are opting for this experimental alternative. An expression over 5%, representing a moderate phenotype, for a few months with a high safety, regarding vector, transfected cells, and implantation procedure, would already be a great success. This may represent an intermediate protocol in which the expression levels and times obtained are lower and shorter respectively as compared to viral vectors, but which provide a potential greater patient safety. This may more readily win acceptance among both patients and haematologists because fatal events in the past due to HIV/HCV infection may constrain the implementation of viruses as vectors.

THE POLITICS OF RISK AND EU GOVERNANCE OF HUMAN MATERIAL

This paper examines the politics of EU risk governance in relation to human material. It is argued that the political context has informed the way in which risks in relation to various types of human material have come to be defined as policy problems at EU level. In turn, this has influenced the design and/or persistence of institutional arrangements to manage such problems. It is further argued that this political context has resulted in a significant level of disconnection in risk governance in the area. This has happened in two ways. First, there has been a growing level of disconnection between institutional and stakeholder demands for a more expansive approach to risk governance in the area and the narrowly-circumscribed competence under Article 152(4)(a) EC, which permits the adoption of risk regulation regimes that set minimum standards of quality and safety in relation to blood, tissue/cells and organs. Second, it has led to the development of institutional arrangements that promote a bifurcated approach to risk governance, specifically in relation to blood and tissues/cells. Although a hybrid of traditional and new governance mechanisms have been employed to address this problem of disconnection, this has nevertheless added a further layer to already complex institutional arrangements for risk governance in the area. It is suggested that a more integrated approach to EU risk governance in relation to human material is needed. Implementing such an approach would contribute to greater clarity, transparency and accountability in decision-making processes, and this could enhance public trust in what is a politically-sensitive area of governance at EU level.