Biology subjects

Langel, U.

Publications and source records attributed to Langel, U..

4 recordsLinked to original sources

bioRxiv2022

Expressed therapeutic protein yields are predicted by transiently transfected mammalian cell population

Therapeutic proteins are currently at the hotspot of innovation in the pharmaceutical medicine. However, their industrial production is technically challenging and improved methods for transcriptional manipulation of mammalian industrial cell cultures are needed. In this work we show that some of the most frequently used lab scale transfection efficacy assays fail to predict performance in the protein production settings. We compare the efficacies of a number of transfection reagents using adherent and suspension mammalian cell cultures and assessment based on several assays that utilize reporter protein quantitation, transfected cell population and post-transfection viability of cells. We validate reporter assays for assessing transfection methods in the lab that predict protein production in industrial settings. We also demonstrate that cell penetrating peptide-based transfection achieve significantly higher protein yields compared to PEI and lipoplex methods in both CHO and HEK293 producer cell lines. Availability of fast lab scale screening methods allows future development of improved transfection methods for protein production. One such potentially effective transient transfection method is the CPP-based approach presented currently.

biochemistry↗

bioRxiv2020

ACE2 peptide fragment interacts with several sites on the SARS-CoV-2 spike protein S1

The influence of the peptide QAKTFLDKFNHEAEDLFYQ on the kinetics of the SARS-CoV-2 spike protein S1 binding to angiotensin-converting enzyme 2(ACE2) was studied to model the interaction of the virus with its host cell. This peptide corresponds to the sequence 24-42 of the ACE2 1 domain, which is the binding site for the S1 protein. The on-rate and off-rate of S1-ACE2 complex formation were measured in the presence of various peptide concentrations using Bio-Layer Interferometry (BLI). The formation of the S1-ACE2 complex was inhibited when the S1 protein was preincubated with the peptide, however, no significant inhibitory effect was observed in the absence of preincubation. Dissociation kinetics revealed that the peptide remained bound to the S1-ACE2 complex and stabilized this complex. Computational mapping of the S1 protein surface for peptide binding revealed two additional sites, located at some distance from the receptor binding domain (RBD) of S1. These additional binding sites affect the interaction between the peptide, the S1 protein, and ACE2.

biochemistry↗

bioRxiv2020

Viability and mitochondrial bioenergetic functions in human colon cancer cells are not affected by treatment with peptides mtCPP1, UPF25, mtgCPP, and mtCPP1gHO

The popularity of the specially synthesized cell-penetrating peptides (CPPs) in cancer treatment has grown recently. The main aim of this study was to investigate the effects of four mitochondrially targeted antioxidant CPPs on the viability and bioenergetic function of mitochondria in human adenocarcinoma Caco-2 cells. The number of viable cells was measured by MTT and trypan blue assays. Respirometry and the permeabilized cell technique were applied to measure the mitochondrial function in this cell line. We did not observe any significant effect of CPPs on the mitochondrial reserve respiratory capacity, the function of respiratory chain complexes, and the inclination of these cancer cells to aerobic glycolysis. mtgCPP peptide with the highest antioxidant activity demonstrated improved mitochondrial coupling efficiency. CPPs do not affect mitochondrial function directly but can be considered in therapeutics as a drug-delivery moleculeCompeting Interest StatementThe authors have declared no competing interest.Abbreviations usedAKadenylate kinase;Ap5Adiadenosine pentaphosphate;CATcarboxyatractyloside;CRCcolorectal cancer;CPPscell-penetrating peptides;HKhexokinase;FAM5-(6)-carboxyfluorescein;MTT3-(4,5-dimethylthiazolyl-2)-2, 5-diphenyltetrazoliumbromide;OXPHOSoxidative phosphorylation;ROSreactive oxygen species;TMPDN,N,N’,N’-tetramethyl-phenylenediamine;VDACvoltage dependent anion channel.View Full Text

cancer biology↗

bioRxiv2020

Mimicry of dopamine 1 receptor signaling with Cell-Penetrating Peptides

In this study, through the use of protein mimicry, a peptide was developed to activate the dopamine 1 receptor signaling pathway in substitution of L-DOPA. The peptide proved to be capable of efficiently ubiquitously penetrating the cell without the need for transfection agents or chiral recognition by specific pathways. Furthermore, the peptide induced the cellular response normally achieved through the activation of the receptor in cells that had not been treated with the natural ligand. The peptide could work as a candidate substitute to L-DOPA, leading the way for a peptides-based treatment for Parkinsons disease.

pharmacology and toxicology↗