Transfection of primary brain capillary endothelial cells for protein synthesis and secretion of recombinant erythropoietin: a strategy to enable protein delivery to the brain

Treatment of chronic disorders affecting the central nervous system (CNS) is complicated by the inability of drugs to cross the blood–brain barrier (BBB). Non-viral gene therapy applied to brain capillary endothelial cells (BCECs) denotes a novel approach to overcome the restraints in this passage, as turning BCECs into recombinant protein factories by transfection could result in protein secretion further into the brain. The present study aims to investigate the possibility of transfecting primary rat brain endothelial cells (RBECs) for recombinant protein synthesis and secretion of the neuroprotective protein erythropoietin (EPO). We previously showed that 4% of RBECs with BBB properties can be transfected without disrupting the BBB integrity in vitro, but it can be questioned whether this is sufficient to enable protein secretion at therapeutic levels. The present study examined various transfection vectors, with regard to increasing the transfection efficiency without disrupting the BBB integrity. Lipofectamine 3000? was the most potent vector compared to polyethylenimine (PEI) and Turbofect. When co-cultured with astrocytes, the genetically modified RBECs secreted recombinant EPO into the cell culture medium both luminally and abluminally, and despite lower levels of EPO reaching the abluminal chamber, the amount of recombinant EPO was sufficient to evolve a biological effect on astrocytes cultured at the abluminal side in terms of upregulated gene expression of brain-derived neurotropic factor (BDNF). In conclusion, non-viral gene therapy to RBECs leads to protein secretion and signifies a method for therapeutic proteins to target cells inside the CNS otherwise omitted due to the BBB.     

Melatonin transport into mitochondria

Melatonin is a well-known, nighttime-produced indole found in bacteria, eukaryotic unicellulars, animals or vascular plants. In vertebrates, melatonin is the major product of the pineal gland, which accounts for its increase in serum during the dark phase, but it is also produced by many other organs and cell types. Such a wide distribution is consistent with its multiple and well-described functions which include from the circadian regulation and adaptation to seasonal variations to immunomodulatory and oncostatic actions in different types of tumors. The discovery of its antioxidant properties in the early 1990s opened a new field of potential protective functions in multiple tissues. A special mention should be made regarding the nervous system, where the indole is considered a major neuroprotector. Furthermore, mitochondria appear as one of the most important targets for the indole’s protective actions. Melatonin’s mechanisms of action vary from the direct molecular interaction with free radicals (free radical scavenger) to the binding to membrane (MLT1A and MLT1B) or nuclear receptors (RZR/RORα). Receptor binding has been associated with some, but not all of the indole functions reported to date. Recently, two new mechanisms of cellular uptake involving the facilitative glucose transporters GLUT/SLC2A and the proton-driven oligopeptide transporter PEPT1/2 have been reported. Here we discuss the potential importance that these newly discovered transport systems could have in determining the actions of melatonin, particularly in the mitochondria. We also argue the relative importance of passive diffusion vs active transport in different parts of the cell.     

Inhibition of protein misfolding and aggregation by natural phenolic compounds

Protein misfolding and aggregation into fibrillar deposits is a common feature of a large group of degenerative diseases affecting the central nervous system or peripheral organs, termed protein misfolding disorders (PMDs). Despite their established toxic nature, clinical trials aiming to reduce misfolded aggregates have been unsuccessful in treating or curing PMDs. An interesting possibility for disease intervention is the regular intake of natural food or herbal extracts, which contain active molecules that inhibit aggregation or induce the disassembly of misfolded aggregates. Among natural compounds, phenolic molecules are of particular interest, since most have dual activity as amyloid aggregation inhibitors and antioxidants. In this article, we review many phenolic natural compounds which have been reported in diverse model systems to have the potential to delay or prevent the development of various PMDs, including Alzheimer’s and Parkinson’s diseases, prion diseases, amyotrophic lateral sclerosis, systemic amyloidosis, and type 2 diabetes. The lower toxicity of natural compounds compared to synthetic chemical molecules suggest that they could serve as a good starting point to discover protein misfolding inhibitors that might be useful for the treatment of various incurable diseases.     

Bakterien im Ovar aquariengehälterter Meeresfische

Summary In the ovary of the ovoviviparous teleostZoarces viviparus L. kept in aquaria, gram-negative bacteria are found. These penetrate the tissue up to the basement membrane which separates the follicle epithelium from the theca.

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Der Deutschen Forschungsgemeinschaft danke ich für die Förderung der Arbeiten, Herrn Prof. Dr.,P. Giesbrecht, Berlin, für Beratung.     

Isozymes inDrosophila cell line

Summary Alcohol dehydrogenase, octanol dehydrogenase and fumarase isozyme patterns inDrosophila tissue culture cells were compared with the respective isozyme development pattern in the parental strain. The cell line lacks ADH activity and its fumarase isozyme pattern resembles the pupae and adult type.     

Dauerüberwachung der fetalen Herzaktionen unter der Geburt mittels Ultraschall

Summary The report concerns a new method for continuous observation of foetal heart frequency during delivery. The apparatus uses ultrasonic energy according to the Doppler-effect. The equipment is compact, reliable and relatively inexpensive. The ultrasonic energy used, is far below the intensities required to produce harmful effects in biological structures.

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Mit Unterstützung der Deutschen Forschungsgemeinschaft und der Paul-Martini-Stiftung der Medizinisch-pharmazeutischen Studiengesellschaft e.V. Frankfurt a. M.     

Dosis-Wirkungs-Beziehungen zwischen Koronardurchfluss und Herzfrequenz für Adenosin

Summary In the isolated guinea-pig heart, it has been found that the amount of adenosine which slows the heart rate is about 100 times greater than the amount which increases coronary flow.