The Characteristics and Function of Small Extracellular Vesicles Derived from Human Bone Marrow and Umbilical Cord Mesenchymal Stromal Cells Are Influenced by Cell Culture Conditions

Extracellular vesicles (EVs) derived from mesenchymal stromal cells (MSC-EVs) have been proposed as a novel therapeutic tool with numerous clinically related advantages. However, their characteristics and functionality are dependent on the source of MSCs and their cell culture conditions. Fetal bovine serum (FBS) provides a source of nutrients and growth factors to the cultured cells. However, certain pitfalls are associated with its supplementation to the culture media, including introduction of exogenous FBS-derived EVs to the cultured cells. Thus, recent practices recommend utilization of serum-free (SF) media or EV-depleted FBS. On the contrary, evidence suggests that the immunomodulatory ability of MSC-EVs can be improved by exposing MSCs to an inflammatory (IF) environment. The objective of this study was to (1) compare EVs isolated from two tissue sources of MSCs that were exposed to various cell culture conditions and (2) to evaluate their anti-inflammatory effects. Bone marrow-derived mesenchymal stromal cells (BM-MSCs) and umbilical cord-derived mesenchymal stromal cells (UC-MSCs) were exposed to either a SF media environment, an IF environment, or media supplemented with 5% EV-depleted FBS. Following isolation of MSC-EVs, the isolates were quantified and evaluated for particle size, phenotypic changes, and their immunomodulatory potential. A statistically significant difference was not identified on the yield and protein concentration of different isolates of EVs from BM-MSCs and UC-MSCs, and all isolates had a circular appearance as evaluated via electron microscopy. A significant difference was identified on the phenotype of different EVs isolates; however, all isolates expressed classical markers such as CD9, CD63, and CD81. The addition of BM-derived MSC-EVs from FBS environment or UC-derived MSC-EVs from IF environment resulted in statistically significant downregulation of IL-6 messenger RNA (mRNA) in stimulated leukocytes. This study confirms that EVs produced by different MSC sources and cell culture conditions affect their phenotype and their immunomodulatory capacities.

Evaluating the Potential of Marine Invertebrate and Insect Protein Hydrolysates to Reduce Fetal Bovine Serum in Cell Culture Media for Cultivated Fish Production

The use of fetal bovine serum (FBS) and the price of cell culture media are the key constraints for developing serum-free cost-effective media. This study aims to replace or reduce the typical 10% serum application in fish cell culture media by applying protein hydrolysates from insects and marine invertebrate species for the growth of Zebrafish embryonic stem cells (ESC) as the model organism. Protein hydrolysates were produced from black soldier flies (BSF), crickets, oysters, mussels, and lugworms with a high protein content, suitable functional properties, and adequate amino-acid composition, with the degree of hydrolysis from 18.24 to 33.52%. Protein hydrolysates at low concentrations from 0.001 to 0.1 mg/mL in combination with 1 and 2.5% serums significantly increased cell growth compared to the control groups (5 and 10% serums) (p < 0.05). All protein hydrolysates with concentrations of 1 and 10 mg/mL were found to be toxic to cells and significantly reduced cell growth and performance (p < 0.05). However, except for crickets, all the hydrolysates were able to restore or significantly increase cell growth and viability with 50% less serum at concentrations of 0.001, 0.01, and 0.1 mg/mL. Although cell growth was enhanced at lower concentrations of protein hydrolysates, the cell morphology was altered due to the lack of serum. The lactate dehydrogenase (LDH) activity results indicated that BSF and lugworm hydrolysates did not alter the cell membrane. In addition, light and fluorescence imaging revealed that the cell morphological features were comparable to those of the 10% serum control group. Overall, lugworm and BSF hydrolysates reduced the serum by up to 90% while preserving excellent cell health.

Limited spermatogenic differentiation of testicular tissue from prepubertal marmosets (Callithrix jacchus) in an in vitro organ culture system

PURPOSE

of the research: To achieve male fertility preservation and restoration, experimental strategies for in vitro germ cell differentiation are required. The effects of two different culture conditions on in vitro maintenance and differentiation of non-human primate germ cells was studied. Three testes from three 6-month-old marmosets were cultured using a gas-liquid interphase system for 12 days. Testicular maturation in pre-culture control and samples cultured in gonadotropin and serum supplemented and non-supplemented culture samples was evaluated using Periodic Acid-Schiff (PAS) and immunohistochemical stainings.

PRINCIPLE RESULTS

Gonadotropins and serum-supplemented tissues demonstrate up to meiotic differentiation (BOULE + Pachytene spermatocyte) and advanced localization of germ cells (MAGEA4+). Moreover, complex (with gonadotropin and marmoset monkey serum) conditions induced progression in somatic cell maturation with advanced seminiferous epithelial organization, maintenance of encapsulation of cultured fragments with peritubular-myoid cells, preservation of tubular structural integrity and architecture.

MAJOR CONCLUSIONS

We report stimulation-dependent in vitro meiotic transition in non-human primate testes. This model represents a novel ex vivo approach to obtain crucial developmental progression.

TGF-β1 potentiates Vγ9Vδ2 T cell adoptive immunotherapy of cancer

Despite its role in cancer surveillance, adoptive immunotherapy using γδ T cells has achieved limited efficacy. To enhance trafficking to bone marrow, circulating Vγ9Vδ2 T cells are expanded in serum-free medium containing TGF-β1 and IL-2 (γδ[T2] cells) or medium containing IL-2 alone (γδ[2] cells, as the control). Unexpectedly, the yield and viability of γδ[T2] cells are also increased by TGF-β1, when compared to γδ[2] controls. γδ[T2] cells are less differentiated and yet display increased cytolytic activity, cytokine release, and antitumor activity in several leukemic and solid tumor models. Efficacy is further enhanced by cancer cell sensitization using aminobisphosphonates or Ara-C. A number of contributory effects of TGF-β are described, including prostaglandin E2 receptor downmodulation, TGF-β insensitivity, and upregulated integrin activity. Biological relevance is supported by the identification of a favorable γδ[T2] signature in acute myeloid leukemia (AML). Given their enhanced therapeutic activity and compatibility with allogeneic use, γδ[T2] cells warrant evaluation in cancer immunotherapy.

Leishmania Parasite: the Impact of New Serum-Free Medium as an Alternative for Fetal Bovine Serum

Background

Flagellated protozoan of the genus Leishmania is the causative agent of vector-borne parasitic diseases of leishmaniasis. Since the production of recombinant pharmaceutical proteins requires the cultivation of host cells in a serum-free medium, the elimination of FBS can improve the possibility of large-scale culture of Leishmania parasite. In the current study, we aimed at evaluating a new serum-free medium in Leishmania parasite culture for future live Leishmania vaccine purposes.

Methods

Recombinant L. tarentolae secreting PpSP15-EGFP and wild type L. major were cultured in serum-free (complete serum-free medium [CSFM]) and serum-supplemented medium. The growth rate, protein expression, and infectivity of cultured parasites in both conditions was then evaluated and compared.

Results

Diff-Quick staining and epi-fluores¬cence microscopy examination displayed the typical morphology of L. major and L. tarentolae-PpSP15-EGFP promastigote grown in CSFM medium. The amount of EGFP expression was similar in CSMF medium compared to M199 supplemented with 5% FBS in flow cytometry analysis of L. tarentolae-PpSP15-EGFP parasite. Also, a similar profile of PpSP15-EGFP proteins was recognized in Western blot analysis of L. tarentolae-PpSP15-EGFP cultured in CSMF and the serum-supplemented medium. Footpad swelling and parasite load measurements showed the ability of CSFM medium to support the L. major infectivity in BALB/C mice.

Conclusion

This study demonstrated that CSFM can be a promising substitute for FBS supplemented medium in parasite culture for live vaccination purposes.

Validation of an adipose-liver human-on-a-chip model of NAFLD for preclinical therapeutic efficacy evaluation

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease and strongly correlates with the growing incidence of obesity and type II diabetes. We have developed a human-on-a-chip model composed of human hepatocytes and adipose tissue chambers capable of modeling the metabolic factors that contribute to liver disease development and progression, and evaluation of the therapeutic metformin. This model uses a serum-free, recirculating medium tailored to represent different human metabolic conditions over a 14-day period. The system validated the indirect influence of adipocyte physiology on hepatocytes that modeled important aspects of NAFLD progression, including insulin resistant biomarkers, differential adipokine signaling in different media and increased TNF-α-induced steatosis observed only in the two-tissue model. This model provides a simple but unique platform to evaluate aspects of an individual factor's contribution to NAFLD development and mechanisms as well as evaluate preclinical drug efficacy and reassess human dosing regimens.

Adhesion-growth factor crosstalk regulates AURKB activation and ERK signalling in re-adherent fibroblasts

Aurora kinases despite their similarity have distinct roles in the cell cycle, which is regulated by cell-matrix adhesion and growth factors. This study reveals loss of adhesion and re-adhesion to differentially regulate Aurora kinases. AURKB activation that drops on the loss of adhesion recovers on re-adhesion in serumdeprived conditions but not in the presence of serum growth factors. A rapid 30 min serum treatment of serumdeprived cells blocks the adhesion-dependent recovery of AURKB, which negatively correlates with Erk activation. AZD mediated inhibition of AURKB in serum-deprived re-adherent cells promotes Erk activation and membrane ruffling, comparable to presence of serum. These studies thus define a novel adhesion-growth factor-dependent regulation of AURKB that controls adhesion-dependent Erk activation in re-adherent fibroblasts.

Honing the Double-Edged Sword: Improving Human iPSC-Microglia Models

Human induced Pluripotent Stem Cell (hiPSC) models are a valuable new tool for research into neurodegenerative diseases. Neuroinflammation is now recognized as a key process in neurodegenerative disease and aging, and microglia are central players in this. A plethora of hiPSC-derived microglial models have been published recently to explore neuroinflammation, ranging from monoculture through to xenotransplantation. However, combining physiological relevance, reproducibility, and scalability into one model is still a challenge. We examine key features of the in vitro microglial environment, especially media composition, extracellular matrix, and co-culture, to identify areas for improvement in current hiPSC-microglia models.

Human Amniotic Epithelial Stem Cells: A Promising Seed Cell for Clinical Applications

Perinatal stem cells have been regarded as an attractive and available cell source for medical research and clinical trials in recent years. Multiple stem cell types have been identified in the human placenta. Recent advances in knowledge on placental stem cells have revealed that human amniotic epithelial stem cells (hAESCs) have obvious advantages and can be used as a novel potential cell source for cellular therapy and clinical application. hAESCs are known to possess stem-cell-like plasticity, immune-privilege, and paracrine properties. In addition, non-tumorigenicity and a lack of ethical concerns are two major advantages compared with embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs). All of the characteristics mentioned above and other additional advantages, including easy accessibility and a non-invasive application procedure, make hAESCs a potential ideal cell type for use in both research and regenerative medicine in the near future. This review article summarizes current knowledge on the characteristics, therapeutic potential, clinical advances and future challenges of hAESCs in detail.

Highly efficient serum-free manipulation of miRNA in human NK cells without loss of viability or phenotypic alterations is accomplished with TransIT-TKO

Natural killer (NK) cells are innate lymphocytes with functions that include target cell killing, inflammation and regulation. NK cells integrate incoming activating and inhibitory signals through an array of germline-encoded receptors to gauge the health of neighbouring cells. The reactive potential of NK cells is influenced by microRNA (miRNA), small non-coding sequences that interfere with mRNA expression. miRNAs are highly conserved between species, and a single miRNA can have hundreds to thousands of targets and influence entire cellular programs. Two miRNA species, miR-155-5p and miR-146a-5p are known to be important in controlling NK cell function, but research to best understand the impacts of miRNA species within NK cells has been bottlenecked by a lack of techniques for altering miRNA concentrations efficiently and without off-target effects. Here, we describe a non-viral and straightforward approach for increasing or decreasing expression of miRNA in primary human NK cells. We achieve >90% transfection efficiency without off-target impacts on NK cell viability, education, phenotype or function. This opens the opportunity to study and manipulate NK cell miRNA profiles and their impacts on NK cellular programs which may influence outcomes of cancer, inflammation and autoimmunity.

Expansion and characterization of cells from surgically removed intervertebral disc fragments in xenogen-free medium

Low back pain due to degeneration of intervertebral disc (IVD) is a major health problem resulting in significant disability as well as adding to the economic burden. Discectomy is a very common procedure done worldwide to relieve this pain. At present all the surgically removed disc tissue is mostly discarded. However, there are reports that state that progenitor cells in the IVD can be grown ex vivo and have the potential to be used for IVD repair and regeneration. We report here that viable cells can be harvested from surgically removed, herniated disc tissue and can be potentially used in cell based therapy. Further, we have successfully replaced xenogenic supplements such as foetal bovine serum with either autologous serum or human platelet lysate for culturing IVD cells from patient's surgically removed disc tissue, without loss of any cell characteristics, including cell surface markers, growth factor secretion in the conditioned medium and osteogenic and chondrogenic differentiation potential in vitro. The present work will not only contribute to overcoming some of the major barriers in carrying out human clinical trials, but also provide a cheap, alternate source of proteins and growth factors for growing IVD cells ex vivo for therapy.

SNX17 Recruits USP9X to Antagonize MIB1-Mediated Ubiquitination and Degradation of PCM1 during Serum-Starvation-Induced Ciliogenesis

Centriolar satellites are non-membrane cytoplasmic granules that deliver proteins to centrosome during centrosome biogenesis and ciliogenesis. Centriolar satellites are highly dynamic during cell cycle or ciliogenesis and how they are regulated remains largely unknown. We report here that sorting nexin 17 (SNX17) regulates the homeostasis of a subset of centriolar satellite proteins including PCM1, CEP131, and OFD1 during serum-starvation-induced ciliogenesis. Mechanistically, SNX17 recruits the deubiquitinating enzyme USP9X to antagonize the mindbomb 1 (MIB1)-induced ubiquitination and degradation of PCM1. SNX17 deficiency leads to enhanced degradation of USP9X as well as PCM1 and disrupts ciliogenesis upon serum starvation. On the other hand, SNX17 is dispensable for the homeostasis of PCM1 and USP9X in serum-containing media. These findings reveal a SNX17/USP9X mediated pathway essential for the homeostasis of centriolar satellites under serum starvation, and provide insight into the mechanism of USP9X in ciliogenesis, which may lead to a better understating of USP9X-deficiency-related human diseases such as X-linked mental retardation and neurodegenerative diseases.

Elucidation of the Interaction between Flavan-3-ols and Bovine Serum Albumin and Its Effect on Their In-Vitro Cytotoxicity

Flavan-3-ols (FLs), specifically catechin and its oligomer B-type procyanidins, are suggested to potently bind to bovine serum albumin (BSA). We examined the interaction between BSA and FLs by fluorescence quenching and found the following order of binding activities to BSA: cinnamtannin A2 (A2; tetramer) > procyanidin C1 (C1; trimer) ≈ procyanidin B2 (B2, dimer) > (−)epicatechin (EC, monomer). Docking simulations between BSA and each compound at the binding site showed that the calculated binding energies were consistent with the results of our experimental assay. FLs exerted cytotoxicity at 1000 μg/mL in F11 cell culture with fetal bovine serum containing BSA. In culture containing serum-free medium, FLs exhibited significant cell proliferation at 10⁻⁴ μg/mL and cytotoxicity was observed at concentrations greater than 10 μg/mL. Results of this study suggest that interactions between polyphenols and BSA should be taken into account when evaluating procyanidin in an in vitro cell culture system.

Immunometabolic phenotype of BV-2 microglia cells upon murine cytomegalovirus infection

Microglia are resident brain macrophages with key roles in development and brain homeostasis. Cytomegalovirus (CMV) readily infects microglia cells, even as a possible primary target of infection in development. Effects of CMV infection on a cellular level in microglia are still unclear; therefore, the aim of this research was to assess the immunometabolic changes of BV-2 microglia cells following the murine cytomegalovirus (MCMV) infection. In light of that aim, we established an in vitro model of ramified BV-2 microglia (BV-2^∅FCS, inducible nitric oxide synthase (iNOS^low), arginase-1 (Arg-1^high), mannose receptor CD206^high, and hypoxia-inducible factor 1α (HIF-1α^low)) to better replicate the in vivo conditions by removing FCS from the cultivation media, while the cells cultivated in 10% FCS DMEM displayed an ameboid morphology (BV-2^{FCS high}, iNOS^high, Arg-1^low, CD206^low, and HIF-1α^high). Experiments were performed using both ramified and ameboid microglia, and both of them were permissive to productive viral infection. Our results indicate that MCMV significantly alters the immunometabolic phenotypic properties of BV-2 microglia cells through the manipulation of iNOS and Arg-1 expression patterns, along with an induction of a glycolytic shift in the infected cell cultures.

On-demand serum-free media formulations for human hematopoietic cell expansion using a high dimensional search algorithm

Substitution of serum and other clinically incompatible reagents is requisite for controlling product quality in a therapeutic cell manufacturing process. However, substitution with chemically defined compounds creates a complex, large-scale optimization problem due to the large number of possible factors and dose levels, making conventional process optimization methods ineffective. We present a framework for high-dimensional optimization of serum-free formulations for the expansion of human hematopoietic cells. Our model-free approach utilizes evolutionary computing principles to drive an experiment-based feedback control platform. We validate this method by optimizing serum-free formulations for first, TF-1 cells and second, primary T-cells. For each cell type, we successfully identify a set of serum-free formulations that support cell expansions similar to the serum-containing conditions commonly used to culture these cells, by experimentally testing less than 1 × 10-5 % of the total search space. We also demonstrate how this iterative search process can provide insights into factor interactions that contribute to supporting cell expansion.

A novel cell-free method to culture Schistosoma mansoni from cercariae to juvenile worm stages for in vitro drug testing

Background

The arsenal in anthelminthic treatment against schistosomiasis is limited and relies almost exclusively on a single drug, praziquantel (PZQ). Thus, resistance to PZQ could constitute a major threat. Even though PZQ is potent in killing adult worms, its activity against earlier stages is limited. Current in vitro drug screening strategies depend on newly transformed schistosomula (NTS) for initial hit identification, thereby limiting sensitivity to new compounds predominantly active in later developmental stages. Therefore, the aim of this study was to establish a highly standardized, straightforward and reliable culture method to generate and maintain advanced larval stages in vitro. We present here how this method can be a valuable tool to test drug efficacy at each intermediate larval stage, reducing the reliance on animal use (3Rs).

Methodology/Principal findings

Cercariae were mechanically transformed into skin-stage (SkS) schistosomula and successfully cultured for up to four weeks with no loss in viability in a commercially available medium. Under these serum- and cell-free conditions, development halted at the lung-stage (LuS). However, the addition of human serum (HSe) propelled further development into liver stage (LiS) worms within eight weeks. Skin and lung stages, as well as LiS, were submitted to 96-well drug screening assays using known anti-schistosomal compounds such as PZQ, oxamniquine (OXM), mefloquine (MFQ) and artemether (ART). Our findings showed stage-dependent differences in larval susceptibility to these compounds.

Conclusion

With this robust and highly standardized in vitro assay, important developmental stages of S. mansoni up to LiS worms can be generated and maintained over prolonged periods of time. The phenotype of LiS worms, when exposed to reference drugs, was comparable to most previously published works for ex vivo harvested adult worms. Therefore, this in vitro assay can help reduce reliance on animal experiments in search for new anti-schistosomal drugs.

Schistosomiasis remains a major health threat, predominantly in developing countries. Even though there has been some progress in search of new drugs, praziquantel remains the only available drug. Probably the most important advance in the search for new drugs was in vitro transformation of cercariae and their subsequent culture. However, hit identification in compound screenings is exclusively tested in skin stage parasites and is only confirmed for more mature worms in a subsequent step. This is in part due to the lack of an easy culture system for advance-stage parasites. We present here a reliable and highly standardized way to generate LiS worms in vitro in a cell-free culture system. The inclusion of in vitro drug tests on advanced-stage parasites in initial hit identification will help to identify compounds that might otherwise be overlooked. Furthermore, the ability to continuously observe the parasite’s development in vitro will provide an important platform for a better understanding of its maturation in the human host. Taken together, this opens up new avenues to investigate the influence of specific cell types or host proteins on the development of Schistosoma mansoni and provides an additional tool to reduce animal use in future drug discovery efforts (3Rs).

Silk Sericin Hydrolysate is a Potential Candidate as a Serum-Substitute in the Culture of Chinese Hamster Ovary and Henrietta Lacks Cells

The silk sericin hydrolysate (SSH) from the waste of silk processing as a substitute of fetal bovine serum (FBS) was used for the culture of Chinese hamster ovary (CHO) cells and Henrietta Lacks (Hela) strain of human cervical cancer cells. The survival ratio of these cells cultured in SSH media were similar to or higher than those in FBS media. Especially after the serum was replaced by low concentration of SSH at 15.0 μg/ml for 5 d, the proliferation of both cells was also similar to or higher than that of FBS group; the percentages of CHO and Hela cells in S-phase were 28.9 and 28.0%, respectively. The former is nearly two times that of FBS group, the latter is also higher than the control group. Reverse transcription-polymerase chain reaction (RT-PCR) revealed that among the differentially expressed genes, the relative expression of CXCL12 gene of CHO cells in SSH group increased, was three times that of serum group, and the relative expression of LCN2 gene of Hela cells increased 2.8 times, indicating that these related genes were activated to promote cell growth and proliferation. These results fully illustrated the hydrolysated sericin has a potential use as serum substitutes in cell culture.

Adipose stem cells and their paracrine factors are therapeutic for early retinal complications of diabetes in the Ins2Akita mouse

BACKGROUND

Early-stage diabetic retinopathy (DR) is characterized by neurovascular defects. In this study, we hypothesized that human adipose-derived stem cells (ASCs) positive for the pericyte marker CD140b, or their secreted paracrine factors, therapeutically rescue early-stage DR features in an Ins2Akita mouse model.

METHODS

Ins2Akita mice at 24 weeks of age received intravitreal injections of CD140b-positive ASCs (1000 cells/1 μL) or 20× conditioned media from cytokine-primed ASCs (ASC-CM, 1 μL). Age-matched wildtype mice that received saline served as controls. Visual function experiments and histological analyses were performed 3 weeks post intravitreal injection. Biochemical and molecular analyses assessed the ASC-CM composition and its biological effects.

RESULTS

Three weeks post-injection, Ins2Akita mice that received ASCs had ameliorated decreased b-wave amplitudes and vascular leakage but failed to improve visual acuity, whereas Ins2Akita mice that received ASC-CM demonstrated amelioration of all aforementioned visual deficits. The ASC-CM group demonstrated partial amelioration of retinal GFAP immunoreactivity and DR-related gene expression but the ASC group did not. While Ins2Akita mice that received ASCs exhibited occasional (1 in 8) hemorrhagic retinas, mice that received ASC-CM had no adverse complications. In vitro, ASC-CM protected against TNFα-induced retinal endothelial permeability as measured by transendothelial electrical resistance. Biochemical and molecular analyses demonstrated several anti-inflammatory proteins including TSG-6 being highly expressed in cytokine-primed ASC-CM.

CONCLUSIONS

ASCs or their secreted factors mitigate retinal complications of diabetes in the Ins2Akita model. Further investigation is warranted to determine whether ASCs or their secreted factors are safe and effective therapeutic modalities long-term as current locally delivered therapies fail to effectively mitigate the progression of early-stage DR. Nonetheless, our study sheds new light on the therapeutic mechanisms of adult stem cells, with implications for assessing relative risks/benefits of experimental regenerative therapies for vision loss.

Promoter Usage and Dynamics in Vascular Smooth Muscle Cells Exposed to Fibroblast Growth Factor-2 or Interleukin-1β

Smooth muscle cells (SMC) in blood vessels are normally growth quiescent and transcriptionally inactive. Our objective was to understand promoter usage and dynamics in SMC acutely exposed to a prototypic growth factor or pro-inflammatory cytokine. Using cap analysis gene expression (FANTOM5 project) we report differences in promoter dynamics for immediate-early genes (IEG) and other genes when SMC are exposed to fibroblast growth factor-2 or interleukin-1β. Of the 1871 promoters responding to FGF2 or IL-1β considerably more responded to FGF2 (68.4%) than IL-1β (18.5%) and 13.2% responded to both. Expression clustering reveals sets of genes induced, repressed or unchanged. Among IEG responding rapidly to FGF2 or IL-1β were FOS, FOSB and EGR-1, which mediates human SMC migration. Motif activity response analysis (MARA) indicates most transcription factor binding motifs in response to FGF2 were associated with a sharp induction at 1 h, whereas in response to IL-1β, most motifs were associated with a biphasic change peaking generally later. MARA revealed motifs for FOS_FOS{B,L1}_JUN{B,D} and EGR-1..3 in the cluster peaking 1 h after FGF2 exposure whereas these motifs were in clusters peaking 1 h or later in response to IL-1β. Our findings interrogating CAGE data demonstrate important differences in promoter usage and dynamics in SMC exposed to FGF2 or IL-1β.

Novel sericin-based hepatocyte serum-free medium and sericin’s effect on hepatocyte transcriptome

AIM

To develop a novel hepatocyte serum-free medium based on sericin, and to explore the effect of sericin on the hepatocyte transcriptome.

METHODS

A controlled trial comparing novel serum-free medium and other media: C3A cells were cultured in our novel serum-free medium, HepatoZYME, complete medium (DMEM/F12 with 100 mL/L FBS), and DMEM/F12, and then cell attachment, proliferation, and function as well as the biocompatibility of the media were assessed. A comparative study of serum-free media with or without 2 mg/mL sericin: the effect of sericin on C3A growth was assessed by cell viability and proliferation, the effect of sericin on C3A cell cycle distribution was determined by flow cytometry, and the effect of sericin on the C3A transcriptome was assessed by gene-chip array and RT-qPCR.

RESULTS

More C3A cells attached to the plate containing our serum-free medium than to those containing HepatoZYME and DMEM/F12 at 24 h post-seeding. Both the viability and proliferation rate of C3A cells in sericin-based serum-free medium were superior to those of cells in HepatoZYME and DMEM/F12 (P < 0.001). The content of albumin and urea in our serum-free medium was significantly higher than that in HepatoZYME and DMEM/F12 throughout the whole culture period (P < 0.001) and was similar to that in complete medium at day 3, 4, and 5. In part 2, cell viability and proliferation were greater in the presence of 2 mg/mL sericin (P < 0.001), as was the proportion of cells in S phase (16.21% ± 0.98% vs 12.61% ± 0.90%, P < 0.01). Gene-chip array analysis indicated that the expression of CCR6, EGFR, and FOS were up-regulated by 2 mg/mL sericin, and RT-qPCR revealed that the expression of CCR6, EGFR, FOS, AKT1, JNK1, NFkB1, MMP-9, MEK2, ERK1/2 and MYC was up-regulated by 2 mg/mL sericin (P < 0.05).

CONCLUSION

We developed a novel hepatocyte serum-free medium. Sericin probably enhances cell attachment through the CCR6-Akt-JNK-NF-κB pathway and promotes cell proliferation through CCR6-mediated activation of the ERK1/2-MAPK pathway.

Characterization of Initial Cell Adhesion on Charged Polymer Substrates in Serum-Containing and Serum-Free Media

Charged substrates are expected to promote cell adhesion via electrostatic interaction, but it remains unclear how cells adhere to these substrates. Here, initial cell adhesion (<30 min) was re-examined on charged substrates in serum-containing and serum-free media to distinguish among various cell adhesion mechanisms (i.e., electrostatic interaction, hydrophobic interaction, and biological interaction). Cationic and anionic methacrylate copolymers were coated on nonionic nontissue culture-treated polystyrene to create charged substrates. Cells adhered similarly on cationic, anionic, and nonionic substrates in serum-free medium via integrin-independent mechanisms, but their adhesion forces differed (anionic > cationic > nonionic substrates), indicating that cell adhesion is not mediated solely by the cells' negative charge. In serum-containing medium, the cells adhered minimally on anionic and nonionic substrates, but they adhered abundantly on cationic substrates via both integrin-dependent and -independent mechanisms. These results suggest that neither electrostatic force nor protein adsorption is accountable for cell adhesion. Conclusively, the observed phenomena revealed a gap in the generally accepted understanding of cell adhesion mechanisms on charged polymeric substrates. A reanalysis of their mechanisms is necessary.

Ginsenoside Rg1 inhibits apoptosis by increasing autophagy via the AMPK/mTOR signaling in serum deprivation macrophages

Ginsenoside Rg1 (Rg1) has been widely used in a broad range of cardiovascular and cerebral-vascular diseases because of its unique therapeutic properties. However, the underlying mechanisms of Rg1 in the treatment of atherosclerosis have not been fully explored. This study sought to determine the precise molecular mechanisms on how Rg1 might be involved in regulating apoptosis in serum deprivation-induced Raw264.7 macrophages and primary bone marrow-derived macrophages. Results demonstrated that Rg1 treatment effectively suppressed apoptosis and the expression of phosphorylation level of mTOR induced by serum deprivation in Raw264.7 macrophages; the expressions of autophagic flux-related proteins including Atg5, Beclin1, microtubule-associated protein 1 light chain 3 (LC3), p62/SQSMT1, and the phosphorylation level of AMPK were concomitantly up-regulated. 3-Methyl-adennine (3-MA), the most widely used autophagy inhibitor, strongly up-regulated the expression of cleaved caspase-3, and blocked the anti-apoptosis function of Rg1 in macrophages. Importantly, autophagic flux was activated by Rg1, while Beclin1 knockdown partially abolished the anti-apoptosis of Rg1. Moreover, compound C, an AMPK inhibitor, partially decreased the expressions of phosphorylation of mTOR, Atg5, Beclin1, LC3, and p62/SQSMT1, which were increased by Rg1. AICAR, an AMPK inducer, promoted the protein expressions of phosphorylation of mTOR, Atg5, Beclin1, LC3, and p62/SQSMT1. In conclusion, Rg1 significantly suppressed apoptosis induced by serum deprivation in macrophages. Furthermore, Rg1 could effectively induce the autophagic flux by attenuating serum deprivation-induced apoptosis in Raw264.7 macrophages through activating the AMPK/mTOR signaling pathway.

Organoid technology for retinal repair

A major cause for vision impairment and blindness in industrialized countries is the loss of the light-sensing retinal tissue in the eye. Photoreceptor damage is one of the main characteristics found in retinal degeneration diseases, such as Retinitis Pigmentosa or age-related macular degeneration. The lack of effective therapies to stop photoreceptor loss together with the absence of significant intrinsic regeneration in the human retina converts such degenerative diseases into permanent conditions that are currently irreversible. Cell replacement by means of photoreceptor transplantation has been proposed as a potential approach to tackle cell loss in the retina. Since the first attempt of photoreceptor transplantation in humans, about twenty years ago, several research groups have focused in the development and improvement of technologies necessary to bring cell transplantation for retinal degeneration diseases to reality. Progress in recent years in the generation of human tissue derived from pluripotent stem cells (PSCs) has significantly improved our tools to study human development and disease in the dish. Particularly the availability of 3D culture systems for the generation of PSC-derived organoids, including the human retina, has dramatically increased access to human material for basic and medical research. In this review, we focus on important milestones towards the generation of transplantable photoreceptor precursors from PSC-derived retinal organoids and discuss recent pre-clinical transplantation studies using organoid-derived photoreceptors in context to related in vivo work using primary photoreceptors as donor material. Additionally, we summarize remaining challenges for developing photoreceptor transplantation towards clinical application.

Serum starvation of ARPE-19 changes the cellular distribution of cholesterol and Fibulin3 in patterns reminiscent of age-related macular degeneration

Retinal pigment epithelium (RPE) has been implicated as key source of cholesterol-rich deposits at Bruch's membrane (BrM) and in drusen in aging human eye. We have shown that serum-deprivation of confluent RPE cells is associated with upregulation of cholesterol synthesis and accumulation of unesterified cholesterol (UC). Here we investigate the cellular processes involved in this response. We compared the distribution and localization of UC and esterified cholesterol (EC); the age-related macular degeneration (AMD) associated EFEMP1/Fibulin3 (Fib3); and levels of acyl-coenzyme A (CoA): cholesterol acyltransferases (ACAT) ACAT1, ACAT2 and Apolipoprotein B (ApoB) in ARPE-19 cells cultured in serum-supplemented and serum-free media. The results were compared with distributions of these lipids and proteins in human donor eyes with AMD. Serum deprivation of ARPE-19 was associated with increased formation of FM dye-positive membrane vesicles, many of which co-labeled for UC. Additionally, UC colocalized with Fib3 in distinct granules. By day 5, serum-deprived cells grown on transwells secreted Fib3 basally into the matrix. While mRNA and protein levels of ACTA1 were constant over several days of serum-deprivation, ACAT2 levels increased significantly after serum-deprivation, suggesting increased formation of EC. The lower levels of intracellular EC observed under serum-deprivation were associated with increased formation and secretion of ApoB. The responses to serum-deprivation in RPE-derived cells: accumulation and secretion of lipids, lipoproteins, and Fib3 are very similar to patterns seen in human donor eyes with AMD and suggest that this model mimics processes relevant to disease progression.

The p75NTR-mediated effect of nerve growth factor in L6C5 myogenic cells

OBJECTIVE

During muscle development or regeneration, myocytes produce nerve growth factor (NGF) as well as its tyrosine-kinase and p75-neurotrophin (p75NTR) receptors. It has been published that the p75NTR receptor could represent a key regulator of NGF-mediated myoprotective effect on satellite cells, but the precise function of NGF/p75 signaling pathway on myogenic cell proliferation, survival and differentiation remains fragmented and controversial. Here, we verified the role of NGF in the growth, survival and differentiation of p75NTR-expressing L6C5 myogenic cells, specifically inquiring for the putative involvement of the nuclear factor κB (NFκB) and the small heat shock proteins (sHSPs) αB-crystallin and Hsp27 in these processes.

RESULTS

Although NGF was not effective in modulating myogenic cell growth or survival in both standard or stress conditions, we demonstrated for the first time that, under serum deprivation, NGF sustained the activity of some key enzymes involved in energy metabolism. Moreover, we confirmed that NGF promotes myogenic fusion and expression of the structural protein myosin heavy chain while modulating NFκB activation and the content of sHSPs correlated with the differentiation process. We conclude that p75NTR is sufficient to mediate the modulation of L6C5 myogenic differentiation by NGF in term of structural, metabolic and functional changes.

α-Adrenergic-mediated activation of human reconstituted fibrinogen receptor (integrin αIIbβ3) in Chinese hamster ovary cells

This work reports the functional studies of CHO cells coexpressing α-adrenergic (αAR) and human fibrinogen (Fg) receptors (integrin αIIbβ3). Stimulation of these cells with α-agonists produced a transient rise in the free cytosolic calcium (Ca++) accompanied by enhanced binding to soluble Fg, and these effects were prevented by specific αAR antagonists. The αadrenergic-induced activation of αIIbβ3 in CHO-αIIbβ3-αAR increased the rate of adhesion and extension of cells onto Fg coated plates, and also induced a soluble Fgand αIIbβ3-dependent formation of cell aggregates, whereas no effects were observed by the stimulation of CHO-αIIbβ3 cells. α-Adrenergic antagonists, the ligand mimetic peptide RGDS, pertussis toxin (PTX), or EDTA, they all prevented the α-adrenergic stimulation of adhesion and aggregation. However, inhibition of PKC prevented the α-adrenergic stimulation of cell adherence, whereas blocking the intracellular Ca++ mobilization impeded the stimulation of cell aggregation. The α-adrenergic activation was associated with phosphorylation of a protein of ∼100 kDa and proteins of the MAPK family. The former was selectively phosphorylated by α-adrenergic stimulation whereas the latter were phosphorylated by the binding of cells to Fg and markedly intensified by α-adrenergic stimulation.

Functionalizing Ascl1 with Novel Intracellular Protein Delivery Technology for Promoting Neuronal Differentiation of Human Induced Pluripotent Stem Cells

Pluripotent stem cells can become any cell type found in the body. Accordingly, one of the major challenges when working with pluripotent stem cells is producing a highly homogenous population of differentiated cells, which can then be used for downstream applications such as cell therapies or drug screening. The transcription factor Ascl1 plays a key role in neural development and previous work has shown that Ascl1 overexpression using viral vectors can reprogram fibroblasts directly into neurons. Here we report on how a recombinant version of the Ascl1 protein functionalized with intracellular protein delivery technology (Ascl1-IPTD) can be used to rapidly differentiate human induced pluripotent stem cells (hiPSCs) into neurons. We first evaluated a range of Ascl1-IPTD concentrations to determine the most effective amount for generating neurons from hiPSCs cultured in serum free media. Next, we looked at the frequency of Ascl1-IPTD supplementation in the media on differentiation and found that one time supplementation is sufficient enough to trigger the neural differentiation process. Ascl1-IPTD was efficiently taken up by the hiPSCs and enabled rapid differentiation into TUJ1-positive and NeuN-positive populations with neuronal morphology after 8 days. After 12 days of culture, hiPSC-derived neurons produced by Ascl1-IPTD treatment exhibited greater neurite length and higher numbers of branch points compared to neurons derived using a standard neural progenitor differentiation protocol. This work validates Ascl1-IPTD as a powerful tool for engineering neural tissue from pluripotent stem cells.

Induction of cytochrome P450 mRNA in porcine primary hepatocytes cultured under serum free conditions: Comparison of freshly isolated cells and cryopreserved

Primary hepatocytes are widely used in the study of dynamic events like regulation of gene expression, as they are superior to most cell-lines. However, the culturing of the hepatocytes often results in loss of phenotype, e.g. the expression of the cytochrome p450s (CYP). The present study investigated the impact of serum in the culture medium of porcine primary hepatocytes (PPH) on markers of dedifferentiation as well as the impact on CYP induction. The effects were studied in both freshly isolated primary hepatocytes as well as cryopreserved. The exclusion of serum in the culturing media were not introducing significant dedifferentiation as judged by the gene expression of α-fetoprotein, albumin, glucose-6-phosphatase and the constitutive expression of selected transcription factors and CYP. The induction of CYP2B22 and CYP3A29 by phenobarbital and rifampicin, were greater in hepatocytes cultured without serum. The same were not observed for TCDD induced CYP1A2 expression. In conclusion, PPH cultured under serum free conditions results in little or no dedifferentiation, while being more responsive to known CYP inducers. Hence, it can be suggested that PPH cultured under serum free conditions provides a reliable hepatocyte model to investigate CYP gene regulation.

Microglia activation induced by serum of SLE patients

To investigate the potential involvement of microglia in the neuropathology of systemic lupus erythematosus (SLE), we examined whether SLE patient sera could activate BV2 microglia in vitro. Exposure to SLE patient sera resulted in morphological changes in the microglia, an increase in MHC II and CD86 protein expression, and an obvious release of nitric oxide and proinflammatory cytokines. However, the SLE sera did not induce a specific change in the production of immunoregulatory cytokines. Inactivating complements or neutralizing proinflammatory cytokines in the SLE sera did not suppress microglial activation. Our results highlight the potential role of microglia in neuroinflammation in SLE patients.

Glioblastoma-derived cells in vitro unveil the spectrum of drug resistance capability - comparative study of tumour chemosensitivity in different culture systems

Resistance to cancer drugs is a complex phenomenon which could be influenced by in vitro conditions. However, tumour-derived cell cultures are routinely used for studies related to mechanisms of drug responsiveness or the search for new therapeutic approaches. The purpose of our work was to identify the potential differences in drug resistance and response to treatment of glioblastoma with the use of three in vitro models: traditional adherent culture, serum-free spheroid culture and novel adherent serum-free culture.The experimental models were evaluated according to 'stemness state' and epithelial-to-mesenchymal transition (EMT) status, invasion capability and their expression pattern of genes related to the phenomenon of tumour drug resistance. Additionally, the response to drug treatments of three different culture models was compared with regard to the type of cell death.Multi-gene expression profiling revealed differences between examined culture types with regard to the expression pattern of the selected genes. Functionally, the examined genes were related to drug resistance and metabolism, DNA damage and repair and cell cycle control, and included potential therapeutic targets.Cytotoxicity analyses confirmed that environmental factors can influence not only the molecular background of glioblastoma drug-resistance and efficiency of treatment, but also the mechanisms/pathways of cell death, which was reflected by a distinct intensification of apoptosis and autophagy observed in particular culture models. Our results suggest that parallel exploitation of different in vitro experimental models can be used to reveal the spectrum of cancer cell resistance capability, especially regarding intra-heterogeneous glioblastomas.

Novel Technique for Suspension Culture of Autologous Chondrocytes Improves Cell Proliferation and Tissue Architecture

We have developed a new and simple method of chondrocyte suspension culture using a spinner bottle with rotation of the matrices. We compared the characteristics of chondrocytes cultured by this method with those grown in standard monolayer cultures. We also determined the optimal nutritional medium for suspension cultures. Periosteum explants seeded with chondrocytes were grown in monolayer and suspension cultures under three conditions: in medium with no additive (control), with 10% fetal bovine serum (FBS), or with 10% autologous serum (AS). After culturing, the explants were harvested, processed for histology, and stained with hematoxylin-eosin or TUNEL, or immunostained for type I, II, and III collagen, and Ki-67 antigen. In monolayer cultures, the attachment of the chondrocytes to the periosteum was weak and the superficial layer consisted of fibrotic tissue and few nucleated cells. Collagen type II staining was strong, but types I and III were weak. Among the suspension cultures the AS group produced the thickest layer of chondrocytes with the fewest apoptotic cells. The superficial layer of cartilage in these cultures stained positive for type I and III collagen and Ki-67 antigen. Among the suspension cultures, total chondroitin and chondroitin-4 sulfate (C-4S) concentration was highest in the AS group, while prostaglandin E2 (PGE2) was highest in the FBS group. In summary, our new method of suspension culture of periosteal explants using rotational matrices combined with AS nutritional media was the most effective method for maintaining the bond between the chondrocyte layer and periosteum, as well as the production of type I and III collagen in the superficial layer.

Growth Properties of Neural Cell Lines Immortalized with the Tsa58 Allele of Sv40 Large T Antigen

In vitro growth properties of three CNS-derived cell lines were compared under a variety of culture conditions. The M213-20 and J30a cell lines were each derived from embryonic CNS culture with the temperature-sensitive (ts) allele of SV40 large T antigen, tsA58, while the A7 cell line was immortalized using wild-type SV40 large T antigen. Cells immortalized with tsA58 SV40 large T proliferate at the permissive temperature, 33° C, while growth is expected to be suppressed at the nonpermissive temperature, 39.5°C. Both the M213-20 and J30a cell lines were capable of proliferating at 39.5°C continuously for up to 6 mo. All three cell lines showed no appreciable differences in growth rates related to temperature over a 7-day period in either serum-containing or defined serum-free media. The percentage of cells in S-phase of the cell cycle did not decrease or was elevated at 39.5°C for all three cell lines. After 3 wk at 39.5°C, the three cell lines also showed positive immunostaining using two monoclonal antibodies reacting with different epitopes of SV40 large T antigen. Double strand DNA sequence analyses of a 300 base pair (bp) fragment of the large T gene from each cell line, which included the ts locus, revealed mutations in both the J30a and M213-20 cell lines. The J30a cell line ts mutation had reverted to wild type, and two additional loci with bp substitutions with predicted amino acid changes were also found. While the ts mutation of the M213-20 cells was retained, an additional bp substitution with a predicted amino acid change was found. The A7 cell line sequence was identical to the reference wild-type sequence. These findings suggest that (a) nucleic acid sequences in the temperature-sensitive region of the tsA58 allele of SV40 large T are not necessarily stable, and (b) temperature sensitivity of cell lines immortalized with tsA58 is not necessarily retained.

Long-term growth comparison studies of FBS and FBS alternatives in six head and neck cell lines

Fetal bovine serum (FBS) is depended upon by investigators as an indispensable supplement in cell and tissue culture systems. Due to increased demand and limited availability, the price of FBS has increased by greater than 300% in the past few years. In addition, there are ethical and scientific controversies about the collection and use of FBS in culture systems. In response to the shortage of FBS, many FBS alternative serum products have been developed. Although many have claimed comparable performance to FBS, their support of long-term cell growth and effects on cell phenotype have not been revealed. In this study, we examined the performances of six bovine calf serum-based FBS alternatives in six head and neck cell lines and compared them with FBS. The results indicate that some of these sera had growth promoting capabilities comparable or superior to that of FBS. Additionally, these alternative sera supported long-term (30 passages) growth of tested cells and exhibited plating efficiencies comparable to that of FBS. Cells cultured in alternative sera also exhibited comparable anchorage-independent growth and similar drug inhibition responses in FBS. Still, caution should be taken in choosing suitable sera given that changes in cell morphology and variations in chemotactic responses were noted for cells maintained in certain sera. These FBS alternatives are more readily available, cost less, and are associated with less ethical concerns, thus making them attractive alternatives to FBS in cell culture systems.

Animal component-free Agrobacterium tumefaciens cultivation media for better GMP-compliance increases biomass yield and pharmaceutical protein expression in Nicotiana benthamiana

Transient expression systems allow the rapid production of recombinant proteins in plants. Such systems can be scaled up to several hundred kilograms of biomass, making them suitable for the production of pharmaceutical proteins required at short notice, such as emergency vaccines. However, large-scale transient expression requires the production of recombinant Agrobacterium tumefaciens strains with the capacity for efficient gene transfer to plant cells. The complex media often used for the cultivation of this species typically include animal-derived ingredients that can contain human pathogens, thus conflicting with the requirements of good manufacturing practice (GMP). We replaced all the animal-derived components in yeast extract broth (YEB) cultivation medium with soybean peptone, and then used a design-of-experiments approach to optimize the medium composition, increasing the biomass yield while maintaining high levels of transient expression in subsequent infiltration experiments. The resulting plant peptone Agrobacterium medium (PAM) achieved a two-fold increase in OD600 compared to YEB medium during a 4-L batch fermentation lasting 18 h. Furthermore, the yields of the monoclonal antibody 2G12 and the fluorescent protein DsRed were maintained when the cells were cultivated in PAM rather than YEB. We have thus demonstrated a simple, efficient and scalable method for medium optimization that reduces process time and costs. The final optimized medium for the cultivation of A. tumefaciens completely lacks animal-derived components, thus facilitating the GMP-compliant large-scale transient expression of recombinant proteins in plants.

Transthyretin: A Transporter Protein Essential for Proliferation of Myoblast in the Myogenic Program

Irregularities in the cellular uptake of thyroid hormones significantly affect muscle development and regeneration. Herein, we report indispensable role of transthyretin (TTR) in maintaining cellular thyroxine level. TTR was found to enhance recruitment of muscle satellite cells to the site of injury, thereby regulating muscle regeneration. Fluorescence-activated cell sorting (FACS) and immunofluorescence analysis of TTR_wt (TTR wild type) and TTR_kd (TTR knock-down) cells revealed that TTR controlled cell cycle progression by affecting the expression of Cyclin A2. Deiodinase 2 (D2) mediated increases in triiodothyronine levels were found to regulate the expression of myogenic marker, myogenin (MYOG). Moreover, use of a coumarin derivative (CD) revealed a significant reduction in cellular thyroxine, thereby indicating that TTR play a role in the transport of thyroxine. Taken together, these findings suggest that TTR mediated transport of thyroxine represents a survival mechanism necessary for the myogenic program. The results of this study will be highly useful to the strategic development of novel therapeutics to combat muscular dystrophies.

Perturbation of redox balance after thioredoxin reductase deficiency interrupts autophagy-lysosomal degradation pathway and enhances cell death in nutritionally stressed SH-SY5Y cells

Oxidative damage and aggregation of cellular proteins is a hallmark of neuronal cell death after neurotrauma and chronic neurodegenerative conditions. Autophagy and ubiquitin protease system are involved in degradation of protein aggregates, and interruption of their function is linked to apoptotic cell death in these diseases. Oxidative modification of cysteine groups in key molecular proteins has been linked to modification of cellular systems and cell death in these conditions. Glutathione and thioredoxin systems provide reducing protons that can effectively reverse protein modifications and promote cell survival. The central role of Thioredoxin in inhibition of apoptosis is well identified. Additionally, its involvement in initiation of autophagy has been suggested recently. We therefore aimed to investigate the involvement of Thioredoxin system in autophagy-apoptosis processes. A model of serum deprivation in SH-SY5Y was used that is associated with autophagy and apoptosis. Using pharmacological and RNA-editing technology we show that Thioredoxin reductase deficiency in this model enhances oxidative stress and interrupts the early protective autophagy and promotes apoptosis. This was associated with decreased protein-degradation in lysosomes due to altered lysosomal acidification and accumulation of autophagosomes as well as impairment in proteasome pathway. We further confirmed that the extent of oxidative stress is a determining factor in autophagy- apoptosis interplay, as upregulation of cellular reducing capacity by N-acetylcysteine prevented impairment in autophagy and proteasome systems thus promoted cell viability. Our study provides evidence that excessive oxidative stress inhibits protein degradation systems and affects the final stages of autophagy by inhibiting autolysosome maturation: a novel mechanistic link between protein aggregation and conversion of autophagy to apoptosis that can be applicable to neurodegenerative diseases.

Cancer stem cells from human glioblastoma resemble but do not mimic original tumors after in vitro passaging in serum-free media

Human gliomas harbour cancer stem cells (CSCs) that evolve along the course of the disease, forming highly heterogeneous subpopulations within the tumour mass. These cells possess self-renewal properties and appear to contribute to tumour initiation, metastasis and resistance to therapy. CSC cultures isolated from surgical samples are considered the best preclinical in vitro model for primary human gliomas. However, it is not yet well characterized to which extent their biological and functional properties change during in vitro passaging in the serum-free culture conditions. Here, we demonstrate that our CSC-enriched cultures harboured from one to several CSC clones from the human glioma sample. When xenotransplanted into mouse brain, these cells generated tumours that reproduced at least three different dissemination patterns found in original tumours. Along the passages in culture, CSCs displayed increased expression of stem cell markers, different ratios of chromosomal instability events, and a varied response to drug treatment. Our findings highlight the need for better characterization of CSC-enriched cultures in the context of their evolution in vitro, in order to uncover their full potential as preclinical models in the studies aimed at identifying molecular biomarkers and developing new therapeutic approaches of human gliomas.

Effect of Acteoside as a Cell Protector to Produce a Cloned Dog

Somatic cell nuclear transfer (SCNT) is a well-known laboratory technique. The principle of the SCNT involves the reprogramming a somatic nucleus by injecting a somatic cell into a recipient oocyte whose nucleus has been removed. Therefore, the nucleus donor cells are considered as a crucial factor in SCNT. Cell cycle synchronization of nucleus donor cells at G0/G1 stage can be induced by contact inhibition or serum starvation. In this study, acteoside, a phenylpropanoid glycoside compound, was investigated to determine whether it is applicable for inducing cell cycle synchronization, cytoprotection, and improving SCNT efficiency in canine fetal fibroblasts. Primary canine fetal fibroblasts were treated with acteoside (10, 30, 50 μM) for various time periods (24, 48 and 72 hours). Cell cycle synchronization at G0/G1 stage did not differ significantly with the method of induction: acteoside treatment, contact inhibition or serum starvation. However, of these three treatments, serum starvation resulted in significantly increased level of reactive oxygen species (ROS) (99.5 ± 0.3%) and apoptosis. The results also revealed that acteoside reduced ROS and apoptosis processes including necrosis in canine fetal fibroblasts, and improved the cell survival. Canine fetal fibroblasts treated with acteoside were successfully arrested at the G0/G1 stage. Moreover, the reconstructed embryos using nucleus donor cells treated with acteoside produced a healthy cloned dog, but not the embryos produced using nucleus donor cells subjected to contact inhibition. In conclusion, acteoside induced cell cycle synchronization of nucleus donor cells would be an alternative method to improve the efficiency of canine SCNT because of its cytoprotective effects.

In vitro and in vivo analysis of human fibroblast reprogramming and multipotency

Multipotent stem cells have potential therapeutic roles in the treatment of Duchenne muscular dystrophy (DMD). However, the limited access to stem cell sources restricts their clinical application. To address this issue, we established a simple in vitro epigenetic reprogramming technique in which skin fibroblasts are induced to dedifferentiate into multipotent cells. In this study, human fibroblasts were isolated from circumcised adult foreskin and were reprogrammed by co-culture for 72 h with fish oocyte extract (FOE) in serum-free medium. The cells were then observed and analyzed by immunofluorescence staining, flow cytometry and in vitro differentiation assays. Then FOE-treated human fibroblasts were transplanted by tail vein injection into irradiated mdx mice, an animal model of DMD. Two months after injection, the therapeutic effects of FOE-treated fibroblasts on mdx skeletal muscle were evaluated by serum creatine kinase (CK) activity measurements and by immunostaining and RT-PCR of human dystrophin expression. The results indicated that the reprogrammed fibroblasts expressed higher levels of the pluripotent antigen markers SSEA-4, Nanog and Oct-4, and were able to differentiate in vitro into adipogenic cells, osteoblastic cells, and myotube-like cells. Tail vein injection of FOE-treated fibroblasts into irradiated mdx mice slightly reduced serum CK activity and the percentage of centrally nucleated myofibers two months after cell transplantation. Furthermore, we confirmed human dystrophin protein and mRNA expression in mdx mouse skeletal muscle. These data demonstrated that FOE-treated fibroblasts were multipotent and could integrate into mdx mouse myofibers through the vasculature.

Reduced serum and hypoxic culture conditions enhance the osteogenic potential of human mesenchymal stem cells

Current protocols for inducing osteogenic differentiation in mesenchymal stem/stromal cells (MSCs) in culture for tissue engineering applications depend on the use of biochemical supplements. However, standard in vitro culture conditions expose cells to ambient oxygen concentrations and high levels of serum (21% O2, 10% FBS) that do not accurately recapitulate the physiological milieu. While we and others have examined MSC behavior under hypoxia, the synergistic effect of low serum levels, such as those present in ischemic injury sites, on osteogenic differentiation has not been clearly examined. We hypothesized that a concomitant reduction of serum and O2 would enhance in vitro osteogenic differentiation of MSCs by more accurately mimicking the fracture microenvironment. We show that serum deprivation, in conjunction with hypoxia, potentiates osteogenic differentiation in MSCs. These data demonstrate the role of serum levels in regulating osteogenesis and its importance in optimizing MSC differentiation strategies.

HIGHLIGHTS

Serum levels, in addition to hypoxia, have a significant effect on MSC osteogenic differentiation. Both naïve and osteogenically induced MSCs exhibit higher osteogenic markers in reduced serum. MSCs deposit the most calcium under 5% O2 in osteogenic media supplemented with 5% FBS. Standard culture conditions (21% O2, 10% FBS) may not be optimal for MSC osteogenic differentiation.

Effect of Concentrated Fibroblast-Conditioned Media on In Vitro Maintenance of Rat Primary Hepatocyte

The effects of concentrated fibroblast-conditioned media were tested to determine whether hepatocyte function can be maintained without direct contact between hepatocytes and fibroblasts. Primary rat hepatocytes cultured with a concentrated conditioned media of NIH-3T3 J2 cell line (final concentration of 55 mg/ml) showed significantly improved survival and functions (albumin and urea) compared to those of control groups. They also showed higher expression levels of mRNA, albumin and tyrosine aminotransferase compared to hepatocyte monoculture. The results suggest that culture with concentrated fibroblast-conditioned media could be an easy method for in vitro maintenance of primary hepatocytes. They also could be contribute to understand and analyze co-culture condition of hepatocyte with stroma cells.

Comparative Analysis of Media and Supplements on Initiation and Expansion of Adipose-Derived Stem Cells

Adipose-derived stem cells (ASCs) are being tested in clinical trials related to cell-based regenerative therapies. Although most of the current expansion protocols for ASCs use fetal calf serum (FCS), xenogeneic-free medium supplements are greatly desired. This study aims to compare the effect of FCS, human platelet lysate (hPL), and a fully defined medium on the initiation and maintenance of ASC cultures. ASCs obtained from five donors were cultured in five different media: StemPro, Dulbecco's modified Eagle's medium (DMEM) supplemented with 10% hPL, or α-minimum essential medium (A-MEM) supplemented with 5% hPL, 10% hPL, or 10% FCS. The effect of media on proliferation, colony-forming units (CFUs), attachment, and morphology was assessed along with cell size, granularity, and immunophenotype. StemPro greatly compromised the initiation of ASC cultures, which could not survive more than a few passages. Cells cultured in A-MEM proliferated at a faster rate than in DMEM, and hPL significantly enhanced cell size, granularity, and proliferation compared with FCS. All media except StemPro supported CFUs equally well. Analysis of surface markers revealed higher levels of CD73 and CD105 in FCS-cultured ASCs, whereas increased levels of CD146 were found in hPL-cultured cells. Multiparametric flow cytometric analysis performed after seven passages revealed the existence of four distinct ASC subpopulations, all positive for CD73, CD90, and CD105, which mainly differed by their expression of CD146 and CD271. Analysis of the different subpopulations might represent an important biological measure when assessing different medium formulations for a particular clinical application.

VIABILITY, IN VITRO DIFFERENTIATION AND MOLECULAR CHARACTERIZATION OF EQUINE ADIPOSE TISSUE-DERIVED MESENCHYMAL STEM CELLS CRYOPRESERVED IN SERUM AND SERUM-FREE MEDIUM

BACKGROUND

The effect of freezing-thawing equine adipose tissue-derived mesenchymal stem cells (eATMSCs) have been poorly investigated.

OBJECTIVE

This study is to test the influence of cryopreservation solution and temperature when adding the cryoprotectant for freezing eATMSCs, and to investigate the effects of cryopreservation on their stemness features.

MATERIALS AND METHODS

Four freezing protocols were evaluated. Viability and proliferation ability of cryopreserved cells were investigated by MTT assay. Fresh and frozen thawed eATMSCs were compared for morphology, phenotypic characteristics (flow cytometry), and differentiation potential.

RESULTS

A higher value of viable cells for samples frozen in FBS and a positive effect of CPA equilibration at low temperature in samples frozen in medium were observed. Morphology was similar for fresh and cryopreserved cells, such as CD expression and differentiation potential.

CONCLUSION

eATMSCs can be safely stored for clinical use. FBS is superior to medium for freezing, but CPA equilibration at low temperature is beneficial when freezing in serum- free medium.

Serum-Free Suspension Culture of MDCK Cells for Production of Influenza H1N1 Vaccines

Development of serum-free suspension cell culture processes is very important for influenza vaccine production. Previously, we developed a MDCK suspension cell line in a serum-free medium. In the present study, the growth kinetics of suspension MDCK cells and influenza virus production in the serum-free medium were investigated, in comparison with those of adherent MDCK cells in both serum-containing and serum-free medium. It was found that the serum-free medium supported the stable subculture and growth of both adherent and suspension cells. In batch culture, for both cell lines, the growth kinetics in the serum-free medium was comparable with those in the serum-containing medium and a commercialized serum-free medium. In the serum-free medium, peak viable cell density (VCD), haemagglutinin (HA) and median tissue culture infective dose (TCID₅₀) titers of the two cell lines reached 4.51×10⁶ cells/mL, 2.94Log₁₀(HAU/50 μL) and 8.49Log₁₀(virions/mL), and 5.97×10⁶ cells/mL, 3.88Log₁₀(HAU/50 μL), and 10.34Log₁₀(virions/mL), respectively. While virus yield of adherent cells in the serum-free medium was similar to that in the serum-containing medium, suspension culture in the serum-free medium showed a higher virus yield than adherent cells in the serum-containing medium and suspension cells in the commercialized serum-free medium. However, the percentage of infectious viruses was lower for suspension culture in the serum-free medium. These results demonstrate the great potential of this suspension MDCK cell line in serum-free medium for influenza vaccine production and further improvements are warranted.

Nucleostemin Knockdown Sensitizes Hepatocellular Carcinoma Cells to Ultraviolet and Serum Starvation-Induced Apoptosis

Nucleostemin (NS) is a GTP-binding protein that is predominantly expressed in embryonic and adult stem cells but not in terminally differentiated cells. NS plays an essential role in maintaining the continuous proliferation of stem cells and some types of cancer cells. However, the role of NS in hepatocellular carcinoma (HCC) remains unclear. Therefore, this study aimed to clarify the role of NS in HCC. First, we demonstrated high expression of NS in most HCC cell lines and liver cancer tissues. NS knockdown induced a severe decline in cell viability of MHCC97H cells as detected by MTT and cell proliferation assays. Next, we used ultraviolet (UV) and serum starvation-induced apoptosis models to investigate whether NS suppression or up-regulation affects HCC cell apoptosis. After UV treatment or serum starvation, apoptosis was strongly enhanced in MHCC97H and Bel7402 cells transfected with small interfering RNA against NS, whereas NS overexpression inhibited UV- and serum-induced apoptosis of HCC cells. Furthermore, after UV irradiation, inhibition of NS increased the expression of pro-apoptosis protein caspase 3 and decreased the expression of anti-apoptosis protein Bcl-2. A caspase 3 inhibitor could obviously prevent NS knockdown-induced apoptosis. In conclusion, our study demonstrated overexpression of NS in most HCC tissues compared with their matched surrounding tissues, and silencing NS promoted UV- and serum starvation-induced apoptosis of MHCC97H and Bel7402 cells. Therefore, the NS gene might be a potential therapeutic target of HCC.

Human Induced Pluripotent Stem Cell-Derived Microvesicles Transmit RNAs and Proteins to Recipient Mature Heart Cells Modulating Cell Fate and Behavior

Microvesicles (MVs) are membrane-enclosed cytoplasmic fragments released by normal and activated cells that have been described as important mediators of cell-to-cell communication. Although the ability of human induced pluripotent stem cells (hiPSCs) to participate in tissue repair is being increasingly recognized, the use of hiPSC-derived MVs (hiPSC-MVs) in this regard remains unknown. Accordingly, we investigated the ability of hiPSC-MVs to transfer bioactive molecules including mRNA, microRNA (miRNA), and proteins to mature target cells such as cardiac mesenchymal stromal cells (cMSCs), and we next analyzed effects of hiPSC-MVs on fate and behavior of such target cells. The results show that hiPSC-MVs derived from integration-free hiPSCs cultured under serum-free and feeder-free conditions are rich in mRNA, miRNA, and proteins originated from parent cells; however, the levels of expression vary between donor cells and MVs. Importantly, we found that transfer of hiPSC components by hiPSC-MVs impacted on transcriptome and proteomic profiles of target cells as well as exerted proliferative and protective effects on cMSCs, and enhanced their cardiac and endothelial differentiation potential. hiPSC-MVs also transferred exogenous transcripts from genetically modified hiPSCs that opens new perspectives for future strategies to enhance MV content. We conclude that hiPSC-MVs are effective vehicles for transferring iPSC attributes to adult somatic cells, and hiPSC-MV-mediated horizontal transfer of RNAs and proteins to injured tissues may be used for therapeutic tissue repair. In this study, for the first time, we propose a new concept of use of hiPSCs as a source of safe acellular bioactive derivatives for tissue regeneration.

The Ankyrin Repeat Domain 49 (ANKRD49) Augments Autophagy of Serum-Starved GC-1 Cells through the NF-κB Pathway

The ankyrin repeat domain 49 (ANKRD49) is an evolutionarily conserved protein highly expressed in testes. However, the function of ANKRD49 in spermatogenesis is unknown. In this study, we found that ANKRD49 resides primarily in nucleus of spermatogonia, spermatocytes and round spermatids. ANKRD49 overexpression augments starvation-induced autophagy in male germ GC-1 cells whereas shRNA knockdown of ANKRD49 attenuates the autophagy. Inhibition of NF-κB pathway by its inhibitors or p65 siRNA prevents the ANKRD49-dependent autophagy augmentation, demonstrating that ANKRD49 enhances autophagy via NF-κB pathway. Our findings suggest that ANKRD49 plays an important role in spermatogenesis via promotion of autophagy-dependent survival.

Decreased FOXD3 Expression Is Associated with Poor Prognosis in Patients with High-Grade Gliomas

Background

The transcription factor forkhead box D3 (FOXD3) plays important roles in the development of neural crest and has been shown to suppress the development of various cancers. However, the expression and its potential biological roles of FOXD3 in high-grade gliomas (HGGs) remain unknown.

Methods

The mRNA and protein expression levels of FOXD3 were examined using real-time quantitative PCR and western blotting in 23 HGG and 13 normal brain samples, respectively. Immunohistochemistry was used to validate the expression FOXD3 protein in 184 HGG cases. The association between FOXD3 expression and the prognosis of HGG patients were analyzed using Kaplan-Meier survival curves and Cox proportional hazards regression models. In addition, we further examined the effects of FOXD3 on the proliferation and serum starvation-induced apoptosis of glioma cells.

Results

In comparison to normal brain tissues, FOXD3 expression was significantly decreased in HGG tissues at both mRNA and protein levels. Immunohistochemistry further validated the expression of FOXD3 in HGG tissues. Moreover, low FOXD3 expression was significantly associated with poor prognosis in HGG patients. Depletion of FOXD3 expression promoted glioma cell proliferation and inhibited serum starvation-induced apoptosis, whereas overexpression of FOXD3 inhibited glioma cell proliferation and promoted serum starvation-induced apoptosis.

Conclusions

Our results indicated that FOXD3 might serve as an independent prognostic biomarker and a potential therapeutic target for HGGs, which warrant further investigation.

Proteomic analysis of the response to cell cycle arrests in human myeloid leukemia cells

Previously, we analyzed protein abundance changes across a 'minimally perturbed' cell cycle by using centrifugal elutriation to differentially enrich distinct cell cycle phases in human NB4 cells (Ly et al., 2014). In this study, we compare data from elutriated cells with NB4 cells arrested at comparable phases using serum starvation, hydroxyurea, or RO-3306. While elutriated and arrested cells have similar patterns of DNA content and cyclin expression, a large fraction of the proteome changes detected in arrested cells are found to reflect arrest-specific responses (i.e., starvation, DNA damage, CDK1 inhibition), rather than physiological cell cycle regulation. For example, we show most cells arrested in G2 by CDK1 inhibition express abnormally high levels of replication and origin licensing factors and are likely poised for genome re-replication. The protein data are available in the Encyclopedia of Proteome Dynamics (

Cytoprotective effect of short-term pretreatment with proanthocyanidin on human gingival fibroblasts exposed to harsh environmental conditions

Our previous study showed that exposing mouse fibroblasts to proanthocyanidin (PA) for only 1 min accelerated cell proliferation in a concentration-dependent manner. In this study, exposing human gingival fibroblasts (HGFs) to PA for 1 min similarly accelerated the proliferative response of the cells. Besides the accelerated proliferative response, PA showed a cytoprotective effect on HGFs exposed to harsh environmental conditions; short-term exposure of HGFs in the mitotic phase to pure water or physiological saline resulted in a lower recovery of viable cells. Pretreatment and concomitant treatment with PA improved the low recovery of cells exposed to pure water or physiological saline. In addition, HGFs exposed to PA for 1 min proliferated well even after being cultured in serum-free medium. In 100% confluent HGFs, being cultured in serum-free medium resulted in a high intracellular reactive oxygen species (ROS) level, but pretreatment with PA prevented the cells from increasing intracellular ROS. Thus, the results suggest that a short-term PA treatment exerts cytoprotective effects on HGFs exposed to harsh environmental conditions by improving the intracellular oxidative stress response.