Recombinant protein production by large-scale transient gene expression in mammalian cells: state of the art and future perspectives

The expansion of the biologics pipeline depends on the identification of candidate proteins for clinical trials. Speed is one of the critical issues, and the rapid production of high quality, research-grade material for preclinical studies by transient gene expression (TGE) is addressing this factor in an impressive way: following DNA transfection, the production phase for TGE is usually 2-10 days. Recombinant proteins (r-proteins) produced by TGE can therefore enter the drug development and screening process in a very short time--weeks. With "classical" approaches to protein expression from mammalian cells, it takes months to establish a productive host cell line. This article summarizes efforts in industry and academia to use TGE to produce tens to hundreds of milligrams of r-proteins for either fundamental research or preclinical studies.

Targeting PIM kinases impairs survival of hematopoietic cells transformed by kinase inhibitor-sensitive and kinase inhibitor-resistant forms of Fms-like tyrosine kinase 3 and BCR/ABL

Previous studies have shown that activation of the signal transducer and activator of transcription 5 (STAT5) plays an essential role in leukemogenesis mediated through constitutive activated protein tyrosine kinases (PTK). Because PIM-1 is a STAT5 target gene, we analyzed the role of the family of PIM serine/threonine kinases (PIM-1 to PIM-3) in PTK-mediated transformation of hematopoietic cells. Ba/F3 cells transformed to growth factor independence by various oncogenic PTKs (TEL/JAK2, TEL/TRKC, TEL/ABL, BCR/ABL, FLT3-ITD, and H4/PDGFbetaR) show abundant expression of PIM-1 and PIM-2. Suppression of PIM-1 activity had a negligible effect on transformation. In contrast, expression of kinase-dead PIM-2 mutant (PIM-2KD) led to a rapid decline of survival in Ba/F3 cells transformed by FLT3-ITD but not by other oncogenic PTKs tested. Coexpression of PIM-1KD and PIM-2KD abrogated growth factor-independent growth of Ba/F3 transformed by several PTKs, including BCR/ABL. Targeted down-regulation of PIM-2 by RNA interference (RNAi) selectively abrogated survival of Ba/F3 cells transformed by various Fms-like tyrosine kinase 3 (FLT3)-activating mutants [internal tandem duplication (ITD) and kinase domain] and attenuated growth of human cell lines containing FLT3 mutations. Interestingly, cells transformed by FLT3 and BCR/ABL mutations that confer resistance to small-molecule tyrosine kinase inhibitors were still sensitive to knockdown of PIM-2, or PIM-1 and PIM-2 by RNAi. Our observations indicate that combined inactivation of PIM-1 and PIM-2 interferes with oncogenic PTKs and suggest that PIMs are alternative therapeutic targets in PTK-mediated leukemia. Targeting the PIM kinase family could provide a new avenue to overcome resistance against small-molecule tyrosine kinase inhibitors.

A functional genetic variation of adenosine deaminase affects the duration and intensity of deep sleep in humans

Slow, rhythmic oscillations (<5 Hz) in the sleep electroencephalogram may be a sign of synaptic plasticity occurring during sleep. The oscillations, referred to as slow-wave activity (SWA), reflect sleep need and sleep intensity. The amount of SWA is homeostatically regulated. It is enhanced after sleep loss and declines during sleep. Animal studies suggested that sleep need is genetically controlled, yet the physiological mechanisms remain unknown. Here we show in humans that a genetic variant of adenosine deaminase, which is associated with the reduced metabolism of adenosine to inosine, specifically enhances deep sleep and SWA during sleep. In contrast, a distinct polymorphism of the adenosine A(2A) receptor gene, which was associated with interindividual differences in anxiety symptoms after caffeine intake in healthy volunteers, affects the electroencephalogram during sleep and wakefulness in a non-state-specific manner. Our findings indicate a direct role of adenosine in human sleep homeostasis. Moreover, our data suggest that genetic variability in the adenosinergic system contributes to the interindividual variability in brain electrical activity during sleep and wakefulness.

Comparison of three different solid-phase microextraction fibres for analysis of essential oils in yacon (Smallanthus sonchifolius) leaves

A headspace solid-phase microextraction (HS-SPME) procedure based on three commercialised fibers (100 microm polydimethylsiloxane, 65 microm polydimethylsiloxane-divinylbenzene and 50/30 microm divinylbenzene-Carboxen-polydimethylsiloxane) is presented for the determination of a selected essential oils in dried leaves of yacon (Smallanthus sonchifolius). The extraction performances of these compounds were compared using fibers with one, two and three coatings. The optimal experimental procedures for the adsorption and desorption of target compounds were determined. Significant parameters affecting sorption process such as sample weight, sorption and desorption time and temperature were optimised and discussed. Finally, the optimised procedures were applied successfully for the determination of these compounds in various yacon species. The relative concentration factors of three characteristic components of yacon were measured for relative evaluation of the fiber efficiency. Main essential oils were isolated from dried yacon leaves by appropriate solid-phase microextraction fiber and semi-quantitative analysis of the target volatiles was conducted by gas chromatography-flame ionisation detection (GC-FID) using a capillary column. Three compounds--beta-pinene, caryophylene and y-cadinene were found as the predominant essential oils. Its relative content was important for specification of yacon varieties. Solid-phase microextraction in combination with gas chromatography enabled a rapid and simple determination of relative content of essential oils in yacon.

Enquête téléphonique sur les pratiques cliniques d'analgésie pour les actes invasifs chez les patients sédatés en réanimation en Île-de-France

To assess the practice of analgesia for invasive procedures in critically ill sedated patient in Ile-de-France (French area including Paris). Observational study: phone survey using a standard questionnaire. Only one senior physician in each of 30 intensive care unit (ICU) was questioned. Baseline sedation included systematic analgesia with narcotics in all ICUs. Only 4 physicians declared using a specific pain scale for sedated patients. Only 3 ICUs used written protocols. Procedures, which were thought to be most invasive (catheterization, pleural drainage, fibroscopy) were in most cases preceded by analgesia, but this was seldom the case for less painful events (venous or arterial puncture, tracheal suctioning). Specific pain scales are still underused. In contrast with current guidelines, analgesia for invasive procedures is not systematic but depends on subjective opinions.

[Stomach rupture after nasal oxygen administration]

We report a case of a spontaneous rupture of a normal stomach after therapeutic oxygen administration. In this case, early treatment precluded the need for a laparotomy. This rare complication highlights the importance of the right positioning of a nasal catheter and leads us to question its role compared to other means of oxygen delivery (nasal cannulae, Hudson mask, Venturi mask).

Determination of acrylonitrile in materials in contact with foodstuffs

Monitoring of the content of free acrylonitrile in plastics used for the preparation of viands is necessary due to its negative effect on human health. A content of 20 ppb is the maximal value of free acrylonitrile in such samples. In this case, head-space gas chromatography is most favourable analytical method when combined with the standard addition method together with a mass-spectrometry detector because of a very low concentration of the analyte. In samples taken for analysis, the content of free acrylonitrile was found to be within 5.1 and 10.3 ppb (microg/kg).

Developmental cell death in dictyostelium does not require paracaspase

Apoptotic cell death often requires caspases. Caspases are part of a family of related molecules including also paracaspases and metacaspases. Are molecules of this family generally involved in cell death? More specifically, do non-apoptotic caspase-independent types of cell death require paracaspases or metacaspases? Dictyostelium discoideum lends itself well to answering these questions because 1) it undergoes non-apoptotic developmental cell death of a vacuolar autophagic type and 2) it bears neither caspase nor metacaspase genes and apparently only one paracaspase gene. This only paracaspase gene can be inactivated by homologous recombination. Paracaspase-null clones were thus obtained in each of four distinct Dictyostelium strains. These clones were tested in two systems, developmental stalk cell death in vivo and vacuolar autophagic cell death in a monolayer system mimicking developmental cell death. Compared with parent cells, all of the paracaspase-null cells showed unaltered cell death in both test systems. In addition, paracaspase inactivation led to no alteration in development or interaction with a range of bacteria. Thus, in Dictyostelium, vacuolar programmed cell death in development and in a monolayer model in vitro would seem not to require paracaspase. To our knowledge, this is the first instance of developmental programmed cell death shown to be independent of any caspase, paracaspase or metacaspase. These results have implications as to the relationship in evolution between cell death and the caspase family.

Effects of scopolamine on matching to sample paradigm and related tests in human subjects

This was a double-blind placebo-controlled study with a cross-over design to examine the effects of scopolamine on cognitive functions in young healthy subjects. Scopolamine hydrobromide was administered subcutaneously to 12 subjects (mean +/- SD age 23.8 +/- 2.2 years) at doses of 0.3 and 0.6 mg in comparison with two placebo conditions. Scopolamine at both doses produced marked sedation as rated by subjects and an observer. In the continuous performance test, vigilance was impaired by both doses of scopolamine. The span of apprehension test showed differing results (only the high dose of scopolamine showed a performance decrement only in the three-character version of the span of apprehension test). Significant impairment by both doses of scopolamine was seen in immediate and delayed free recall, continuous visual recognition, running word recognition and running picture recognition. While scopolamine caused a significant slowing in average reaction times for simultaneous matching as well as for delayed matching, subjects made more errors under scopolamine compared to placebo only in delayed matching, not in simultaneous matching. Also, the main outcome of matching to sample showed significant effects only in delayed matching, not in simultaneous matching. Notable in this study is the incongruity between the simultaneous matching test and the span of apprehension test on the one hand and the other cognitive tests used on the other. These results demonstrated that scopolamine has a greater effect on memory than on attention. Thus, the scopolamine-induced effects in the present study seem to be more relevant to Alzheimer's disease in an advanced phase than to normal aging.

Smoke-free cafe in an unregulated European city: highly welcomed and economically successful

OBJECTIVE

In a unique setting with two identical cafes, which only differed in their smoking ordinances, this study assessed the influence of smoking policies on the choice of the cafe, investigated regulatory preferences among customers, and evaluated the claim that smoking cafes have better sales performance in a city without smoking bans.

METHODS

In a parallel assessment, customers of both cafes answered a questionnaire. Sales were compared and air pollutants were measured to confirm air quality differences.

RESULTS

The two customer groups (n = 177) differed only with regard to smoking status (p < 0.01). The smoking regulation was the most often cited selection criterion (83%). In the non-smoking café, 89% indicated that they were usually annoyed by smoke in coffee houses, and 62% would avoid or leave cafes for this reason. Two thirds stated that all cafe/restaurants should offer the opportunity of a smoke-free environment. However, almost half stated that mandatory regulations are not needed and that customers should make individual arrangements based on tolerance and courtesy. Those who were informed about the health effects of secondhand smoke were more likely to call for clear policies. Whereas sales showed no differences, tips were 22% (p < 0.001) higher in the non-smoking cafe.

CONCLUSION

In a generation raised in smoking friendly environments, customers paradoxically ask for a landmark shift towards smoke-free opportunities, while substantially adhering to the tobacco industry paradigm of promoting "tolerance" rather than smoke-free policies. Given the clear preference of a large number of customers, hospitality businesses could, however, greatly profit from offering smoke-free environments even in the absence of regulatory policies.

Biological and biochemical properties of the carbon composite and polyethylene implant materials

We studied the biocompatibility of the carbon composites and polyethylene materials with and without collagen or collagen and proteoglycan cover. We used the in vitro technology to study the adhesion of model cells evalution, their metabolic activity and the production of TNF-alpha as a cytokine model. Under in vivo condition, the biocompatibility of tested polymers were studied in the implantation experiment, subcutaneously in the interscapular region in the laboratory rat. We have found in the in vitro assay favorable proliferation and the smallest production of pro-inflammatory TNF-alpha cytokine in cells adherent to the hydrophobic polyethylene material coated with biological macromolecules. Using in vivo tests performed by the implantation of materials to the rat we demonstrated that the materials are not cytotoxic. The tissue capsule surrounding the implants was not significantly influenced by the type of the implant and the pre-treatment by the biological molecules. However, the foreign-body giant multinucleated cells were observed only in the vicinity of the collagen - covered hydrophobic polyethylene implant. Interestingly, while the collagen coating improved the biocompatibility of tested polymers in vitro, the inflammatory reaction against this covered materials was higher under in vivo conditions. The pre-treatment of carbon composites by both types of biological macromolecules reduced the occurrence of carbon debris in the implantation site. The tested carbon composites and polyethylene materials are not toxic. The pre-treatment of the materials by extracellular matrix components increased their biological tolerance in vitro and reduced implant wears in animal experiment, which can be important for the medical application.

Dictyostelium cell death: early emergence and demise of highly polarized paddle cells

Cell death in the stalk of Dictyostelium discoideum, a prototypic vacuolar cell death, can be studied in vitro using cells differentiating as a monolayer. To identify early events, we examined potentially dying cells at a time when the classical signs of Dictyostelium cell death, such as heavy vacuolization and membrane lesions, were not yet apparent. We observed that most cells proceeded through a stereotyped series of differentiation stages, including the emergence of "paddle" cells showing high motility and strikingly marked subcellular compartmentalization with actin segregation. Paddle cell emergence and subsequent demise with paddle-to-round cell transition may be critical to the cell death process, as they were contemporary with irreversibility assessed through time-lapse videos and clonogenicity tests. Paddle cell demise was not related to formation of the cellulose shell because cells where the cellulose-synthase gene had been inactivated underwent death indistinguishable from that of parental cells. A major subcellular alteration at the paddle-to-round cell transition was the disappearance of F-actin. The Dictyostelium vacuolar cell death pathway thus does not require cellulose synthesis and includes early actin rearrangements (F-actin segregation, then depolymerization), contemporary with irreversibility, corresponding to the emergence and demise of highly polarized paddle cells.

[New materials suitable for implantation--preparation for implants]

PURPOSE OF THE STUDY

Connective tissue components, particularly collagen and proteoglycan, stimulate cell proliferation and thus promote tissue regeneration. This fact was utilized to test some new implant materials, which were covered by these components, for the speed and quality of their encapsulation.

MATERIAL

The materials tested included polyethylene (PE) with either a hydrophobic (HPHO) or a hydrophilic (HPHI) surface and the C-C composite. Before implantation in experimental animals, the materials were coated with a thin layer of collagen-proteoglycan copolymer.

METHODS

Collagen was obtained from calf hide (ISC 40 fraction) and proteoglycan was isolated from calf cartilage with 2M GuHCl. The concentrations of elements in implant materials were assessed by the method of ESCA photoelectron spectroscopy (electron spectroscopy for chemical analysis) and, using a comparison of the values of electron binding energies at inner levels with the published ones, the chemical states of elements were identified.

RESULTS

Carbon, oxygen and silicon were identified on the surface of the PE HPHI sample; carbon, oxygen, calcium, manganese and sulfur were found on the PE HPHO sample and nitrogen, oxygen and fluorine were present on the C-C composite.

DISCUSSION

In our group of patients there was a small rate of rheumatoid arthritis, while in most literature these patients are predominant. In accordance with the outcomes of other authors, ASS is fraught with recurrence. ASS does not strike to fibrous capsule, like an open surgery synovectomy, and from these islands synovialis could regenerate.

CONCLUSIONS

The presence of manganese and calcium on the surfaces of the materials investigated indicates the existence of a collagen-proteoglycan copolymer, which contains NH2 and COO groups derived from collagen and SO4 groups from proteoglycan. It is necessary to verify this theoretical assumption based on measurement data in a biological experiment.

[Changes in the articular compartment in advanced osteoarthritis]

PURPOSE OF THE STUDY

Both synovial and bone forms of osteoarthritis (OA) are characterized by inflammatory processes in the articular compartment. Increasing evidence suggests that changes in bone tissue are important for the deterioration or loss of joint function. Therefore it is reasonable to shift emphasis from research on cartilage to that on other articular tissues, particularly on subchondral bone. The aim of the study was to demonstrate the involvement of several cytokines in OA development and, on the basis of changes of joint markers, to assess the extent of inflammatory process.

MATERIAL

A total of 60 patients with an osseous form of osteoarthritis of the knee joint (28 patients) or the hip joining (32 patients) underwent total knee or hip arthroplasty. The mean age of our patients was 66.7 +/- 10.4 years. Preoperative clinical and radiographic examinations were carried out as well as routine laboratory tests on blood and urine. Samples of urine, blood serum (BS) and synovial fluid (SF), extracts from cartilage (CA) and synovial membrane (SM) and granulation bone tissue were analysed for markers indicating the presence of inflammatory processes in joints.

METHOD

The following markers of inflammatory activity in the bone compartment were investigated: pyridinoline (PYR), deoxypyridinoline (D-PYR), bone alkaline phosphatase (BAP) and chondrex (CHON). The levels of cytokines IL-1 alpha, IL-8, IL-10 and TNF-alpha were assayed by immunoanalysis (ELISA and IMMULITE system) in BS, CA, SM, GT and SF. The tissue samples were obtained during arthroplasty.

RESULTS

In the patients with osteoarthritis, the urinary levels of PYR and D-PYR were higher than control values (70.33 +/- 34.93 vs (41.6 +/- 10.6 nmol/mmol creatinine). No significant differences were found between pre- and post-operative levels. Similarly, the serum levels of BAP and CHON compared with control values were higher (27.65 +/- 12.21 vs 12.2 +/- 2.7 U/L and (96.35 +/- 58.83 vs 43.2 +/- 14.5 ng/ml, respectively). In all articular compartments and in synovial fluid, the level of cytokine IL-8 exceeded concentrations of the other cytokines. In blood serum, only IL-10 levels were markedly increased as against the control group (17.35 +/- 5.82 vs 9.80 +/- 4.40 pg/ml).

DISCUSSION

Primary osteoarthritis is the most common joint disease that deteriorates with age. Its symptoms are pain and a lower range of motion in the joint affected. The initial involvement of articular cartilage progresses to degenerative changes involving synovial and bony structures. This degenerative disease gradually develops into an inflammatory disease. At this stage, osseous tissue shows an increase in metabolism and bone destruction results. In the control of inflammatory reactions by the immune system, cytokines, among other proteins, play an important role: some may enhance inflammation by activating leukocytes (IL-1, TNF-alpha, IL-8) while others, such as IL-10, have anti-inflammatory effects.

CONCLUSION

During osteoarthritis, the articular compartment shows high metabolic processes that, in some patients, may increase and even persist some time after arthroplasty.

Increased IkappaB kinase activity is associated with activated NF-kappaB in acute myeloid blasts

NF-kappaB/Rel transcription factors are modulators of immune and inflammatory processes and are also involved in malignancy. Phosphorylation of the IkappaB inhibitors by the IkappaB kinase (IKK) complex leads to their proteasomal degradation, resulting in activated NF-kappaB. Here, we investigated the activation status of NF-kappaB and the IKK complex in acute myeloid leukemia (AML). Gelshift assays revealed an increased level of activated nuclear NF-kappaB in myeloid blasts. Both bone marrow and peripheral blood blasts from AML patients showed enhanced IKK activity relative to controls, whereas the IKK protein concentrations were comparable. In addition, an increased level of IkappaB-alpha was detected in AML blast cells, although this appeared to be insufficient to block nuclear translocation of NF-kappaB, also confirmed by immunofluorescence. In subtype M4 and M5 AML cells a more extensive NF-kappaB activation and higher IKK activity was found than in M1/M2 specimens. Isolated AML blasts cultured ex vivo responded to external stimulation (TNF, LPS) by further IKK activation, IkappaB degradation and NF-kappaB activation. Preincubation with the proteasome inhibitor PSI inhibited the NF-kappaB system in isolated AML blasts. This study established for the first time a dysregulation of IKK signaling in AML leading to increased NF-kappaB activity suggesting potential therapeutic avenues.

[Relation between cytokines, adhesive immunoglobulins and matrix metalloproteinases in osteoarthritic joints]

BACKGROUND

The dysbalance of proteinase production and their inhibitors leads to destruction of tissues in many pathological processes. Recently it was shown that the expression of proteinases is regulated also by interactions of cells which is mediated by adhesive molecules. We wanted to find out whether this mechanism is involved also in the destruction of joints in osteoarthritis.

METHODS AND RESULTS

Cartilage, synovial and subchondral bone tissues, and synovial fluids were obtained from 23 joints after total endoprosthesis surgery. The solid tissues were extracted by TRIS buffer. The investigated protein concentrations were assessed immunochemicaly. In all specimens gelatinase A, gelatinase B, stromelysin-1, TIMP-1, soluble adhesive molecules sICAM-1 and sVCAM-1 and cytokines TNF-alpha and IL-8 were found. In cartilage and synovial fluid the proteolytic potential of metalloproteinases was balanced with high concentrations of their inhibitor TIMP-1 (259.4 +/- 105.2 pmol/g protein vs 2343.8 +/- 637.5 pmol/g protein in synovial fluid, p < 0.00001, and 178.9 +/- 175.7 pmol/g dry weight vs 647.2 +/- 561.3 pmol/g dry weight in cartilage, p < 0.001) but in synovial tissues and pathological subchondral bones was not (257.4 +/- 617.2 pmol/g dry weight vs 171.3 +/- 170.8 pmol/g dry weight in synovium, p = 0.61716, and 17.4 +/- 15.4 pmol/g dry weight 33.6 +/- 33.3 pmol/g dry tissue in pathological subchondral bone, p = 0.16705).

CONCLUSION

From correlation analysis ensues that the bond of ICAM-1 and VCAM-1 on chondrocytes with appropriate integrin ligands probably leads to up-regulation of gelatinase A and B and to down-regulation of TIMP-1. Moreover it is apparent that TNF-alpha up-regulates both investigated adhesive molecules followed and stromelysin-1 and TIMP-1.