Treating cell culture media with UV irradiation against adventitious agents: Minimal impact on CHO performance

Sterility of cell culture media is an important concern in biotherapeutic processing. In large scale biotherapeutic production, a unit contamination of cell culture media can have costly effects. Ultraviolet (UV) irradiation is a sterilization method effective against bacteria and viruses while being non‐thermal and non‐adulterating in its mechanism of action. This makes UV irradiation attractive for use in sterilization of cell culture media. The objective of this study was to evaluate the effect of UV irradiation of cell culture media in terms of chemical composition and the ability to grow cell cultures in the treated media. The results showed that UV irradiation of commercial cell culture media at relevant disinfection doses impacted the chemical composition of the media with respect to several carboxylic acids, and to a minimal extent, amino acids. The cumulative effect of these changes, however, did not negatively influence the ability to culture Chinese Hamster Ovary cells, as evaluated by cell viability, growth rate, and protein titer measurements in simple batch growth compared with the same cells cultured in control media exposed to visible light. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:1190–1195, 2014     

Motexafin gadolinium, a tumor-selective drug targeting thioredoxin reductase and ribonucleotide reductase

Motexafin gadolinium (MGd) is a chemotherapeutic drug that selectively targets tumor cells and mediates redox reactions generating reactive oxygen species. Thioredoxin (Trx), NADPH, and thioredoxin reductase (TrxR) of the cytosol/nucleus or mitochondria are major thiol-dependent reductases with many functions in cell growth, defense against oxidative stress, and apoptosis. Mammalian TrxRs are selenocysteine-containing flavoenzymes; MGd was an NADPH-oxidizing substrate for human or rat TrxR1 with a Km value of 8.65 microM (kcat/Km of 4.86 x 10(4) M(-1) s(-1)). The reaction involved redox cycling of MGd by oxygen producing superoxide and hydrogen peroxide. MGd acted as a non-competitive inhibitor (IC50 of 6 microM) for rat TrxR. In contrast, direct reaction between MGd and reduced human Trx was negligible. The corresponding reaction with reduced Escherichia coli Trx was also negligible, but MGd was a better substrate (kcat/Km of 2.23 x 10(5) M(-1) s(-1)) for TrxR from E. coli and a strong inhibitor of Trx-dependent protein disulfide reduction. Ribonucleotide reductase (RNR), a 1:1 complex of the non-identical R1- and R2-subunits, catalyzes the essential de novo synthesis of deoxyribonucleotides for DNA synthesis using electrons from Trx and TrxR. MGd inhibited recombinant mouse RNR activity with either 3 microM reduced human Trx (IC50 2 microM) or 4 mM dithiothreitol (IC50 6 microM) as electron donors. Our results demonstrate MGd-induced enzymatic generation of reactive oxygen species by TrxR plus a powerful inhibition of RNR. This may explain the effects of the drug on cancer cells, which often overproduce TrxR and have induced RNR for replication and repair.     

Leishmania major: Protective capacity of DNA vaccine using amastin fused to HSV-1 VP22 and EGFP in BALB/c mice model

An intercellular spreading strategy using herpes simplex virus type 1 (HSV-1) VP22 protein is employed to enhance DNA vaccine potency of Leishmania major amastin antigen in BALB/c mice model. We evaluated the immunogenicity and protective efficacy of plasmid DNA vaccines encoding amastin-enhanced green fluorescent protein (EGFP) and VP22-amastin-EGFP. Optimal cell-mediated immune responses were observed in BALB/c mice immunized with VP22-amastin-EGFP as assessed by cytokine gene expression analysis using real time RT-PCR. Vaccination with the VP22-amastin-EGFP fusion construct elicited significantly higher IFN-gamma response upon antigen stimulation of splenocytes from immunized mice compared to amastin as a sole antigen. Mice immunized by VP22-amastin-EGFP showed partial protection following infectious challenge with L. major, as measured by parasite load in spleens. These results suggest that the development of DNA vaccines encoding VP22 fused to a target Leishmania antigen would be a promising strategy to improve immunogenicity and DNA vaccine potency.     

The early effects of uninephrectomy on rat kidney metabolic state using optical imaging

Uninephrectomy (UNX) is known to result in structural and metabolic changes to the remaining kidney, although it is uncertain if this alters the mitochondrial redox state and how soon such changes may occur. A custom‐designed fluorescence cryo‐imaging technique was used to quantitatively assess the effect of UNX by measuring the levels of nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD) in the remaining kidney. Kidneys were snap‐frozen 3 days following UNX, and the intrinsic fluorescence of NADH and FAD were optically acquired. The 3D images were created to characterize the NADH/FAD redox ratios (RR) of the right kidneys, which underwent UNX and the remaining kidneys 3 days following UNX. Both the NADPH‐oxidases (Nox2 and Nox4) and the mitochondria are the main sources of reactive oxygen species (ROS) production in tubular epithelial cells. Responses to the UNX were obtained in kidneys of normal Sprague Dawley (SD) rats, Dahl salt‐sensitive (SS) rats and SS rats in which NADPH‐oxidase isoform 4 (Nox4) was knocked out (SS^Nox4?/?). The results found that each of the strains exhibited similar increase in kidney weights averaging 17% after 3 days of UNX. SD and SS^Nox4?/?rats both exhibited global reductions of the RR (P < .05) with a similar tendency observed in SS rats (P < .08), indicating increased ROS production. The unexpected reduction of the RR in the remnant kidneys of SS^Nox4?/? rats indicates that mechanisms independent of H₂O₂ produced from Nox4 may be responsible for this global increase of ROS. We propose that the reduced RR was largely a consequence of enhanced mitochondrial bioenergetics due to increased tubular workload of the remaining kidney. The data indicate that mitochondria become the dominant source of increased ROS following UNX and could represent an important hypertrophic signaling mechanism.     

LAMP3 (CD208) Expression in Squamous Cell Carcinoma and Epithelial Dysplasia of the Oral Cavity and Clinicopathological Characteristics of Unfavorable Prognosis

Background:This study aimed to evaluate LAMP3 (CD208) gene expression in oral squamous cell carcinoma (OSCC) and dysplastic oral epithelium by quantitative real-time polymerase chain reaction (qPCR) and compare LAMP3 expression in different disease grades and stages.Methods:In this study, 60 OSCC and dysplastic oral epithelium samples were obtained from the Mashhad University of Medical Sciences together with their demographic and clinicopathological documents. LAMP3 expression was measured by qPCR.Results:LAMP3 expression was significantly greater in OSCC than in dysplasia samples (P=0.001), in grade III OSCC than in grades I and II, and also greater in advanced than in early OSCC disease stage (P=0.001).Conclusion:The significantly greater LAMP3 expression in OSCC than in dysplastic epithelium indicates a role for LAMP3 in carcinogenesis in oral mucosa. Our results suggest LAMP3 may be useful as an anticancer target and/or to predict disease pathogenesis in OSCC patient’s cells.Key Words: Clinicopathological, Grade, Epithelial dysplasia, LAMP3, Stage, Squamous cell carcinoma.     

A bioinspired 3D shape olibanum-collagen-gelatin scaffolds with tunable porous microstructure for efficient neural tissue regeneration

There are a number of procedures for regeneration of injured nerves; however, tissue engineering scaffolds seems to be a promising approach for recovery of the functionality of the injured nerves. Consequently, in this study, olibanum-collagen-gelatin scaffolds were fabricated by freeze-cast technology. For this purpose, the olibanum and collagen were extracted from natural sources. The effect of solidification gradient on microstructure and properties of scaffolds was investigated. Scanning electron microscopy micrographs showed the formation of lamellar-type microstructure in which the average pore size reduced with an increase in freezing rate. According to the results, the prepared scaffolds at lower freezing rate showed a slight reduction in mechanical strength while the swelling and biodegradation ratio were increased due to the presence of larger pores and unidirectional channels. The composition of scaffolds and oriented microstructure improved cellular interaction. In addition, scaffolds with lower freezing rate exhibited promising results in terms of adhesion, spreading, and proliferation. In brief, the synthesized scaffolds at lower solidification rate have the potential for more in vitro and in vivo analyses to regeneration of neural defects.     

Hydrogels Composed of Cyclodextrin Inclusion Complexes with PLGA-PEG-PLGA Triblock Copolymers as Drug Delivery Systems

Although conventional pharmaceuticals have many drug dosage forms on the market, the development of new therapeutic molecules and the low efficacy of instant release formulations for the treatment of some chronic diseases and specific conditions encourage scientists to invent different delivery systems. To this purpose, a supramolecular hydrogel consisting of the tri-block copolymer PLGA-PEG-PLGA and α-cyclodextrin was fabricated for the first time and characterised in terms of rheological, morphological, and structural properties. Naltrexone hydrochloride and vitamin B12 were loaded, and their release profiles were determined.