12-O-Tetradecanoylphorbol-13-acetate increases cardiomyogenesis through PKC/ERK signaling

12-O-Tetradecanoylphorbol-13-acetate (TPA) is the most widely used diacylglycerol (DAG) mimetic agent and inducer of protein kinase C (PKC)-mediated cellular response in biomedical studies. TPA has been proposed as a pluripotent cell differentiation factor, but results obtained have been inconsistent. In the present study we show that TPA can be applied as a cardiomyogenesis-promoting factor for the differentiation of mouse embryonic stem (mES) cells in vitro. The mechanism of TPA action is mediated by the induction of extracellular signal-regulated kinase (ERK) activity and the subsequent phosphorylation of GATA4 transcription factor. Interestingly, general mitogens (FGF, EGF, VEGF and serum) or canonical WNT signalling did not mimic the effect of TPA. Moreover, on the basis of our results, we postulate that a TPA-sensitive population of cardiac progenitor cells exists at a certain time point (after days 6–8 of the differentiation protocol) and that the proposed treatment can be used to increase the multiplication of ES cell-derived cardiomyocytes. © 2020, The Author(s).Czech Science FoundationGrant Agency of the Czech Republic [18-18235S]; Faculty of Science of Masaryk University [MUNI/A/1145/2017]; Ministry of Education, Youth and Sports of the Czech Republic (MEYS CR) [LQ1605

Polyaniline cryogels: Biocompatibility of novel conducting macroporous material

Polyaniline cryogel is a new unique form of polyaniline combining intrinsic electrical conductivity and the material properties of hydrogels. It is prepared by the polymerization of aniline in frozen poly(vinyl alcohol) solutions. The biocompatibility of macroporous polyaniline cryogel was demonstrated by testing its cytotoxicity on mouse embryonic fibroblasts and via the test of embryotoxicity based on the formation of beating foci within spontaneous differentiating embryonic stem cells. Good biocompatibility was related to low contents of low-molecular-weight impurities in polyaniline cryogel, which was confirmed by liquid chromatography. The adhesion and growth of embryonic stem cells, embryoid bodies, cardiomyocytes, and neural progenitors prove that polyaniline cryogel has the potential to be used as a carrier for cells in tissue engineering or bio-sensing. The surface energy as well as the elasticity and porosity of cryogel mimic tissue properties. Polyaniline cryogel can therefore be applied in bio-sensing or regenerative medicine in general, and mainly in the tissue engineering of electrically excitable tissues. © 2017 The Author(s).Czech Science Foundation [17-05095S]; Ministry of Education, Youth and Sports of the Czech Republic - Program NPU I [LO1504]; European Regional Development Fund [CZ.1.05/2.1.00/19.0409

Modulation of differentiation of embryonic stem cells by polypyrrole: The impact on neurogenesis

The active role of biomaterials in the regeneration of tissues and their ability to modulate the behavior of stem cells in terms of their differentiation is highly advantageous. Here, polypyrrole, as a representantive of electro-conducting materials, is found to modulate the behavior of embryonic stem cells. Concretely, the aqueous extracts of polypyrrole induce neurogenesis within embryonic bodies formed from embryonic stem cells. This finding ledto an effort to determine the physiological cascade which is responsible for this effect. The polypyrrole modulates signaling pathways of Akt and ERK kinase through their phosphorylation. These effects are related to the presence of low-molecularweight compounds present in aqueous polypyrrole extracts, determined by mass spectroscopy. The results show that consequences related to the modulation of stem cell differentiation must also be taken into account when polypyrrole is considered as a biomaterial. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Czech Science FoundationGrant Agency of the Czech Republic [19-16861S, 17-05466S]; internal grant agency of Tomas Bata University in Zlin [IGA/CPS/2021/001]; Slovenian Research AgencySlovenian Research Agency - Slovenia [P2-0082]; Ministry of Education, Youth and Sports of the Czech Republic-DKRVO [RP/CPS/2020/001]RP/CPS/2020/001; Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT; Grantová Agentura České Republiky, GA ČR: 17-05466S, 19-16861S; Javna Agencija za Raziskovalno Dejavnost RS, ARRS: P2-0082; Univerzita Tomáše Bati ve Zlíně: IGA/CPS/2021/00

The biocompatibility of polyaniline and polypyrrole: A comparative study of their cytotoxicity, embryotoxicity and impurity profile

Conducting polymers (CP), namely polyaniline (PANI) and polypyrrole (PPy), are promising materials applicable for the use as biointerfaces as they intrinsically combine electronic and ionic conductivity. Although a number of works have employed PANI or PPy in the preparation of copolymers, composites, and blends with other polymers, there is no systematic study dealing with the comparison of their fundamental biological properties. The present study, therefore, compares the biocompatibility of PANI and PPy in terms of cytotoxicity (using NIH/3T3 fibroblasts and embryonic stem cells) and embryotoxicity (their impact on erythropoiesis and cardiomyogenesis within embryonic bodies). The novelty of the study lies not only in the fact that embryotoxicity is presented for the first time for both studied polymers, but also in the elimination of inter-laboratory variations within the testing, such variation making the comparison of previously published works difficult. The results clearly show that there is a bigger difference between the biocompatibility of the respective polymers in their salt and base forms than between PANI and PPy as such. PANI and PPy can, therefore, be similarly applied in biomedicine when solely their biological properties are considered. Impurity content detected by mass spectroscopy is presented. These results can change the generally accepted opinion of the scientific community on better biocompatibility of PPy in comparison with PANI. © 2018 Elsevier B.V.LO1504, NPU, Northwestern Polytechnical University; 17-05095S, GACR, Grantová Agentura České Republiky; MŠMT, Ministerstvo Školství, Mládeže a TělovýchovyCzech Science Foundation [17-05095S]; Ministry of Education, Youth and Sports of the Czech Republic - Program NPU I [LO1504

Orthotopic model for the analysis of melanoma circulating tumor cells

Abstract Metastatic melanoma, a highly lethal form of skin cancer, presents significant clinical challenges due to limited therapeutic options and high metastatic capacity. Recent studies have demonstrated that cancer dissemination can occur earlier, before the diagnosis of the primary tumor. The progress in understanding the kinetics of cancer dissemination is limited by the lack of animal models that accurately mimic disease progression. We have established a xenograft model of human melanoma that spontaneously metastasizes to lymph nodes and lungs. This model allows precise monitoring of melanoma progression and is suitable for the quantitative and qualitative analysis of circulating tumor cells (CTCs). We have validated a flow cytometry-based protocol for CTCs enumeration and isolation. We could demonstrate that (i) CTCs were detectable in the bloodstream from the fourth week after tumor initiation, coinciding with the lymph node metastases appearance, (ii) excision of the primary tumor accelerated the formation of metastases in lymph nodes and lungs as early as one-week post-surgery, accompanied by the increased numbers of CTCs, and (iii) CTCs change their surface protein signature. In summary, we present a model of human melanoma that can be effectively utilized for future drug efficacy studies

Stem cell differentiation on conducting polyaniline

Polyaniline is a promising conducting polymer with broad application potential in biomedicine. Its medical use, however, requires both biocompatibility and suitable physico-chemical and surface properties. The microstructure, electrical properties, and surface characteristics of polyaniline salt, polyaniline base, and polyaniline deposited with biologically active poly(2-acrylamido-2-methyl-1-propanesulfonic acid) were revealed using atomic force microscopy, contact angle measurements, and Raman spectroscopy. As conducting polymers can be preferentially applied in tissue engineering of heart and nervous tissues, the cardiomyogenesis in pure cardiomyocytes derived from embryonic stem cells and neurogenesis in neural progenitors isolated from embryonal 13 dpc brain were further investigated. The results show that neither cardiomyogenesis nor neurogenesis were influenced by any of the tested polyaniline films. However, the most favorable cell behaviour was observed on pristine polyaniline base; therefore, polyaniline in pristine forms without any further modification can be applied in a variety of biomedical fields. © The Royal Society of Chemistry 2015.13-08944S, GACR, Czech Science FoundationCzech Science Foundation [13-08944S]; Ministry of Education, Youth and Sports of the Czech Republic - Program NPU I [LO1504

Hierarchically structured polystyrene-based surfaces amplifying fluorescence signals: Cytocompatibility with human induced pluripotent stem cell

An innovative multi-step phase separation process was used to prepare tissue culture for the polystyrene-based, hierarchically structured substrates, which mimicked in vivo microenvironment and architecture. Macro-(pore area from 3000 to 18,000 µm2; roughness (Ra) 7.2 ± 0.1 µm) and meso-(pore area from 50 to 300 µm2; Ra 1.1 ± 0.1 µm) structured substrates covered with micro-pores (area around 3 µm2 ) were prepared and characterised. Both types of substrate were suitable for human-induced pluripotent stem cell (hiPSC) cultivation and were found to be beneficial for the induction of cardiomyogenesis in hiPSC. This was confirmed both by the number of promoted proliferated cells and the expressions of specific markers (Nkx2.5, MYH6, MYL2, and MYL7). Moreover, the substrates amplified the fluorescence signal when Ca2+ flow was monitored. This property, together with cytocompatibility, make this material especially suitable for in vitro studies of cell/material interactions within tissue-mimicking environments. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Grantová Agentura České Republiky, GA ČR: 18-18235S, 19-16861S, IGA//CPS/2021/001, IGA/FT/2021/010Czech Science FoundationGrant Agency of the Czech Republic [19-16861S, 18-18235S]; TBU [IGA//CPS/2021/001, IGA/FT/2021/010

Electrochemically prepared composites of graphene oxide and conducting polymers: Cytocompatibility of cardiomyocytes and neural progenitors

The cytocompatibility of cardiomyocytes derived from embryonic stem cells and neural progenitors, which were seeded on the surface of composite films made of graphene oxide (GO) and polypyrrole (PPy-GO) or poly(3,4-ethylenedioxythiophene) (PEDOT-GO) are reported. The GO incorporated in the composite matrix contributes to the patterning of the composite surface, while the electrically conducting PPy and PEDOT serve as ion-to-electron transducers facilitating electrical stimulation/sensing. The films were fabricated by a simple one-step electropolymerization procedure on electrically conducting indium tin oxide (ITO) and graphene paper (GP) substrates. Factors affecting the cell behaviour, i.e. the surface topography, wettability, and electrical surface conductivity, were studied. The PPy-GO and PEDOT-GO prepared on ITO exhibited high surface conductivity, especially in the case of the ITO/PPy-GO composite. We found that for cardiomyocytes, the PPy-GO and PEDOT-GO composites counteracted the negative effect of the GP substrate that inhibited their growth. Both the PPy-GO and PEDOT-GO composites prepared on ITO and GP significantly decreased the cytocompatibility of neural progenitors. The presented results enhance the knowledge about the biological properties of electroactive materials, which are critical for tissue engineering, especially in context stimuli-responsive scaffolds. © 2019 Elsevier B.V.Czech Science FoundationGrant Agency of the Czech Republic [19168615]; Ministry of Education, Youth and Sports of the Czech Republic - Program NPU I [L01504]; Jane and Aatos Erkko Foundation (Finland

Interaction of nanostructured TiO2 biointerfaces with stem cells and biofilm-forming bacteria

Nanostructured TiO2 nanotubes (NTs) of diameters from 15 to 100 nm were fabricated by an electrochemical anodization process. Biofilm-positive strains of Bacillus cereus and Pseudomonas aeruginosa behaved similarly on all TiO2 NTs as well as on native titanium (Ti) foil. The adhesion and growth of mesenchymal stem cells (MSc), embryonic stem cells (ESc), and pure cardiomyocytes derived from ESc exhibited significant differences. MSc as well as ESc were, in contrast to cardiomyocytes, able to adhere, and grow on TiO2 NTs. A correlation between NTs diameter and cell behaviour was however observed in the case of MSc and ESc. MSc were not in a physiological state in the case of 100 nm TiO2 NTs, while ESc were not able to grow on 15 nm TiO2 NTs. It can be stated that these differences can be assigned to different diameters of the NTs but not to the chemistry of the surface. This is the first study describing the comprehensive behaviour of both eukaryotic and prokaryotic cells on TiO2 NTs. On the basis of obtained results, it can be concluded that new generation of medical devices providing selective cell behaviour can be fabricated by optimizing the nanoscale morphology of TiO2. © 2017 Elsevier B.V.17-05095S, GACR, Grantová Agentura České Republiky; ARRS - project L7-7566, ARRS, Javna Agencija za Raziskovalno Dejavnost RS; LO1504, MŠMT, Ministerstvo Školství, Mládeže a TělovýchovyCzech Science Foundation [1705095S]; Slovenian Research Agency (ARRS) [L7-7566]; Ministry of Education, Youth and Sports of the Czech Republic under Program NPU I [LO1504]; TBU [Zlin IGA/CPS/2017/001

Stimuli-responsive thin film composites of conducting polymers and cellulose nanocrystals for tissue engineering

Thin composite films comprising two primary representatives of conducting polymers, poly(3, 4-ethylenedioxythiophene) (PEDOT) and polypyrrole (PPy), with eco-friendly cellulose nanocrystals (CNC) were prepared through electrochemical polymerization. The combination of CNC and PEDOT (or PPy) results in the formation of films with highly different surface topography and thickness. Intriguingly, different surface conductivity of PEDOT and PPy was revealed by atomic force microscopy albeit that the electrochemical properties were rather similar. The biological properties of the composites in contact with prospective human induced pluripotent stem cells (hiPSC) and cardiomyocytes derived from hiPSC demonstrated good cytocompatibility of both composites and their potential in engineering of electro-sensitive tissues. The as-prepared conducting, eco-friendly and cytocompatible composites are thus promising candidates for biomedical applications where stimuli-responsivity is a crucial cell-instructive property.Jane ja Aatos Erkon Säätiö, J&AE; Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT; Grantová Agentura České Republiky, GA ČR, (23-07425S); DKRVO, (RP/CPS/2022/001