Conditional reprogrammed human limbal epithelial cell model for anti-SARS-CoV-2 drug screening

To minimize the global pandemic COVID-19 spread, understanding the possible transmission routes of SARS-CoV-2 and discovery of novel antiviral drugs are necessary. We describe here that the virus can infect ocular surface limbal epithelial, but not other regions. Limbal supports wild type and mutant SARS-CoV-2 entry and replication depending on ACE2, TMPRSS2 and possibly other receptors, resulting in slight CPE and arising IL-6 secretion, which symbolizes conjunctivitis in clinical symptoms. With this limbal model, we have screened two natural product libraries and discovered several unreported drugs. Our data reveal important commonalities between COVID-19 and ocular infection with SARS-CoV-2, and establish an ideal cell model for drug screening and mechanism research.

Metabolomics comparison of metabolites and functional pathways in the SH-SY5Y cell model of Parkinson's disease under PEMF exposure

Objective

PEMF is an emerging technique in the treatment of Parkinson's disease (PD) due to its potential improvement of movement speed. The aim of this study was to investigate the metabolic profiles of pulsed electromagnetic fields (PEMFs) in an SH-SY5Y cell model of PD.

Methods

The SH-SY5Y cell model of PD was induced by 1-methyl-4-phenylpyridinium (MPP+). Liquid chromatography mass spectrometry (LC‒MS)-based untargeted metabolomics was performed to examine changes in the PD cell model with or without PEMF exposure. We conducted KEGG pathway enrichment analysis to explore the potentially related pathways of the differentially expressed metabolites.

Results

A total of 275 metabolites were annotated, and 27 significantly different metabolites were found between the PEMF treatment and control groups (VIP >1, P < 0.05), mainly including 4 amino acids and peptides, 4 fatty acid esters, 2 glycerophosphoethanolamines, 2 ceramides and 2 monoradylglycerols; among them, 12 metabolites were upregulated, and 15 were downregulated. The increased expression levels of glutamine, adenosine monophosphate and taurine were highly associated with PEMF stimulation in the PD model. The enrichment results of differentially abundant metabolite functional pathways showed that biological processes such as the mTOR signaling pathway, PI3K-Akt signaling pathway, and cAMP signaling pathway were significantly affected.

Conclusion

PEMFs affected glutamine, adenosine monophosphate and taurine as well as their functional pathways in an in vitro model of PD. Further functional studies regarding the biological effect of these changes are required to evaluate the clinical efficacy and safety of PEMF treatment in PD.

Human Bone Marrow Derived-Mesenchymal Stem Cells Treatment for Autoimmune Premature Ovarian Insufficiency

BACKGROUND

Premature ovarian insufficiency (POI) is a relatively common gynecologic endocrine disorder, which is hypogonadism associated with amenorrhea, increased levels of gonadotropins, and hypoestrogenism. POI resulting from ovarian autoimmunity is a poorly understood clinical condition lacking effective treatments. This study is aimed to investigate the therapeutic effect of mesenchymal stem cells (MSCs) on autoimmune premature ovarian insufficiency.

METHODS

In this study, in vivo and in vitro experiments were conducted to clarify the therapeutic effects and possible mechanisms of human bone marrow-derived MSCs (hBMSCs) on autoimmune POI, and to provide an experimental evidence for the treatment of autoimmune POI by hBMSCs. Noteworthy, in this study, we used interferon-gamma (IFN-γ) to induce autoimmune inflammation in human granulosa cell line KGN, simulating the pathophysiological changes of granulosa cells in autoimmune POI, and therefore sought to establish an in vitro cell model of autoimmune POI, which is still lacking in experimental methodology.

RESULTS

And we found that, in vitro, co-culture of hBMSCs could promote granulosa cell proliferation, inhibit apoptosis, improve hormone synthesis capacity, and reduce the occurrence of pyroptosis; and in vivo, hBMSCs resulted in improved estrous cycle disorders in autoimmune POI mice, increased serum estradiol, decreased follicle-stimulating hormone, improved ovarian morphology, increased number of primordial and primary follicles, decreased number of atretic follicles, and decreased ovarian granulosa cell apoptosis.

CONCLUSIONS

hBMSCs have therapeutic effects on autoimmune POI both in vitro and in vivo.

N-acetylcysteine modulates rotenone-induced mitochondrial Complex I dysfunction in THP-1 cells

Mitochondrial Complex I dysfunction and oxidative stress have been part of the pathophysiology of several diseases ranging from mitochondrial disease to chronic diseases such as diabetes, mood disorders and Parkinson's Disease. Nonetheless, to investigate the potential of mitochondria-targeted therapeutic strategies for these conditions, there is a need further our understanding on how cells respond and adapt in the presence of Complex I dysfunction. In this study, we used low doses of rotenone, a classical inhibitor of mitochondrial complex I, to mimic peripheral mitochondrial dysfunction in THP-1 cells, a human monocytic cell line, and explored the effects of N-acetylcysteine on preventing this rotenone-induced mitochondrial dysfunction. Our results show that in THP-1 cells, rotenone exposure led to increases in mitochondrial superoxide, levels of cell-free mitochondrial DNA, and protein levels of the NDUFS7 subunit. N-acetylcysteine (NAC) pre-treatment ameliorated the rotenone-induced increase of cell-free mitochondrial DNA and NDUFS7 protein levels, but not mitochondrial superoxide. Furthermore, rotenone exposure did not affect protein levels of the NDUFV1 subunit but induced NDUFV1 glutathionylation. In summary, NAC may help to mitigate the effects of rotenone on Complex I and preserve the normal function of mitochondria in THP-1 cells.

[Overview and prospects of an in vitro cell model for studying liver fibrosis]

Liver fibrosis incidence and adverse outcomes are high; however, there are no known chemical drugs or biological agents that are specific and effective for treatment. The paucity of a robust and realistic in vitro model for liver fibrosis is one of the major causes hindering anti-liver fibrosis drug development. This article summarizes the latest progress in the development of in vitro cell models for liver fibrosis, with a focus based on the analysis of induction and activation of hepatic stellate cells, cell co-culture, and 3D model co-construction, as well as concurrent potential methods based on hepatic sinusoidal endothelial cell establishment.

Effects of dielectric barrier discharge cold plasma on structure, surface hydrophobicity and allergenic properties of shrimp tropomyosin

Effects of dielectric barrier discharge (DBD) cold plasma (CP) on structure, surface hydrophobicity and allergenic properties of tropomyosin (TM) in shrimp were investigated in this study. Results showed that the molecular weight of TM increased and the protein concentration decreased with CP treatment time increased. The content of free amino acids was increased by 74.7 % and the distribution of aromatic amino acids was altered. The content of α-helix was decreased by 69 % and the surface hydrophobicity increased by 57.8 % after 20 min treatment. Allergenicity analysis showed that the IgE binding capacity decreased by 96 % after 20 min treatment, and the degranulation indexes of KU812 cells like the β-HEX release rate, the intracellular calcium ion intensity, the release of histamine and inflammatory cytokines (IL-4, TNF-α) were decreased by 32.5 %, 31.0 %, 37.3 %, 51.7 %, and 70.2 %, respectively. The current study confirmed that DBD CP could reduce the TM allergenicity through structural changes.

A cell model about symmetric and asymmetric stem cell division

We construct a multi-stage cell lineage model including self-renewal, apoptosis, cell movement and the symmetrical/asymmetrical division of stem cells. The evolution of cell populations can be described by coupled reaction-diffusion partial differential equations, and the propagating wavefront speeds can be obtained analytically and verified by numerical solutions of the equations. The emphasis is on the effect of symmetric/asymmetric division of stem cells on the population and propagating dynamics of cell lineage. It is found that stem cells' asymmetric cell division (ACD) can move the phase boundary of the homogenous solution of the system. The population of the cell lineage will be promoted in presence of ACD. The concentration of stem cells increases with ACD but that of differentiated daughter cells decreases with ACD. In addition, it is found that the propagating speed of the stem cells can be evaluated with ACD. When the daughter cells move fast to a new space, stem cells can catch them up through increasing ACD. Our results may suggest a mechanism of collective migration of cell lineage through cooperation between ACD of stem cells and fast diffusion of the daughter cells.

Establishment of a CaCC-based Cell Model and Method for High-throughput Screening of M3 Receptor Drugs

Muscarinic acetylcholine receptor subtype 3 (M3 receptor) is a G Protein-Coupled Receptor (GPCR) that mediates many important physiological functions. Currently, most M3 receptor drugs also have high affinity for other subtypes of muscarinic acetylcholine receptors (mAChRs) and produce the risk of side effects. Therefore, in order to find M3 receptor drugs with high specificity, high activity and low side effects, we established a cell model and method for efficient and sensitive screening of M3 receptor based on calcium-activated chloride channels (CaCCs), and this method is also suitable for the screening of other GPCR drugs. This screening model consists of Fischer rat thyroid follicular epithelial (FRT) cells that endogenously express M3 receptors, CaCCs, and the indicator YFP-H148Q/I152L. We verified that the model can sensitively detect changes in intracellular Ca²⁺ concentration using fluorescence quenching kinetics experiments, confirmed the screening function of the model by applying available M3 receptor drugs, and also evaluated the good performance of the model in high-throughput screening.

The cell as a realization of the (M, R) system

Robert Rosen defines organisms as natural systems closed to efficient causation, and proposes the (M, R) system as a model for them. He argues that the study of this formal system provides an understanding of living beings that cannot be obtained from conventional biology. However, he recognizes that answering specific questions about specific organisms requires identifying his relational concepts with specific characteristics of individual biological systems. Therefore, to apply the proposed model to biological research, it is necessary to recover the material systems through a process of realization of the formal system. The description of the cell as a realization of the (M, R) system has been notoriously problematic to date. This article posits a cell model based on the functional organization of cellular biochemical processes, and on Rosen's construction of the replication function. Then, based on the proposed model, the meaning of the replication function is discussed and the (M, R) system is analyzed as a theory of life.

Leukemogenic SHP2 mutations lead to erythropoietin independency of HCD-57 cells: a novel model for preclinical research of SHP2-mutant JMML

Leukemogenic SHP2 mutations occur in 35% of patients with juvenile myelomonocytic leukemia (JMML), a rare but fatal hematopoietic malignancy without representative cell models, which are urgently needed to investigate the pathogenesis and to develop novel therapeutic strategies. In this study, we established stable cell lines with aberrant signaling resembling SHP2-mutant JMML through retroviral expression of SHP2-D61Y/E76K in HCD-57 cells, a murine erythroleukemia cell line that depends on erythropoietin (EPO) for survival. SHP2-D61Y/E76K drives the survival and proliferation of HCD-57 cells in the absence of EPO, but not in Ba/F3 cells in the absence of IL-3. Transformed HCD-57 cells showed activated MAPK signaling that is consistent with SHP2-mutant JMML. Transformed HCD-57 cells were sensitive to dasatinib and trametinib, two targeted drugs previously reported to inhibit SHP2-mutant JMML cells. Furthermore, we injected mutant SHP2-transformed HCD-57 cells into immune-deficient mice intravenously and found that these cells rapidly proliferated in the spleen and bone marrow, providing an excellent model for in vivo testing of drugs targeting the aberrant signaling of mutant SHP2. In conclusion, we established the novel cell lines HCD-57/SHP2-E76K and -D61Y that depended on signaling of mutant SHP2 for survival, thus resembling SHP2-mutant JMML. Our model is a valuable tool to investigate the pathogenic mechanisms of mutant SHP2 and targeted drugs for SHP2-mutant JMML.

Artificial Cells for Dissecting Exocytosis

The fusion of vesicles and exocytosis release of neurotransmitters into the extracellular space for detection and chemical signal decoding by neighboring cells is the key process in neuronal communication. It is important to understand what regulates exocytosis because the amount of neurotransmitters released into the synaptic cleft has a direct impact on brain function such as cognition learning and memory as well as on brain malfunctions. Much success in molecular biology can be credited for the existence of simplified model systems. Therefore, for gaining deeper insights into the details of exocytosis and what controls vesicle-mediated neurotransmission, functional artificial cells for exocytosis have been developed that can be used for studying various biophysical aspects and roles of molecules affecting exocytosis, which is difficult to study in living cells. Here, we describe the design and fabrication of specific artificial cell models and how chemical measurements at these cells can be implemented for probing dynamics of the exocytosis fusion pore and its effect on the regulation of neurochemical release. We introduce bottom-up synthetic methods for constructing model cells using protein-free giant unilamellar vesicles (GUV) as starting material, which allows further tuning of molecular complexity in a manner that is not possible in living cells and therefore can be used for dissecting the role of essential molecular components affecting the exocytosis process. The experimental setup uses microscopy video recording, micromanipulation and microelectroinjection techniques, and amperometry detection to study neurotransmitter release from these cells mimicking exocytosis.

Strategies for understanding the role of cellular heterogeneity in the pathogenesis of lung cancer: a cell model for chronic exposure to cigarette smoke extract

Background

Human tumors are highly heterogeneous at the cellular, molecular, genetic and functional levels. Tumor heterogeneity has tremendous impact on cancer progression and treatment responses. However, the mechanisms for tumor heterogeneity have been poorly understood due to the lack of experimental models.

Methods

This study provides a novel exploration and analysis of the impacts of cellular and molecular heterogeneity of human lung epithelial cells on their malignant transformation following chronic exposure to cigarette smoke extracts.

Results

The ability of cigarette smoke extract (CSE) to cause malignant transformation of the human bronchial epithelial cells (16HBE) is dependent on the sizes of the cells. Epithelial-mesenchymal transition (EMT) plays an important role in this process. Mechanistically, CSE-induced malignant transformation of 16HBE cells was closely linked to the reduced relative telomere length of the larger 16HBE cells, thereby up-regulation of the expression of stemness genes.

Conclusions

These findings provide novel insights for understanding the impact of cellular heterogeneity in lung cancer development. The in vitro transformation model described in this study could be extrapolated to studying the pathogenesis of other malignancies, as well as for mechanistic studies that are not feasible in vivo.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-02116-6.

[Research progress on animal and cell models of pneumoconiosis]

Pneumoconiosis is an occupational lung disease with the highest incidence in China. There is no effective treatment drug at present. Animal and cell models are the basis for exploring its pathogenesis and developing effective drugs. In this paper, we sort out the methods of animal models of pneumoconiosis and the different cell models induced by dust in recent years, by analyzing and summarizing the advantages and disadvantages, modeling time, pathology and changes in important indicators of different preparation methods of animal models, as well as different cell models induced by the dust to simulate different pathological models and pathological stages, to provide basis for the application and improvement of pneumoconiosis model.

Dysregulated mitochondrial metabolism upon cigarette smoke exposure in various human bronchial epithelial cell models

Exposure to cigarette smoke (CS) is the primary risk factor for developing chronic obstructive pulmonary disease. The impact of CS exposure on the molecular mechanisms involved in mitochondrial quality control in airway epithelial cells is incompletely understood. Undifferentiated or differentiated primary bronchial epithelial cells were acutely/chronically exposed to whole CS (WCS) or CS extract (CSE) in submerged or air-liquid interface conditions. Abundance of key regulators controlling mitochondrial biogenesis, mitophagy and mitochondrial dynamics was assessed. Acute exposure to WCS or CSE increased the abundance of components of autophagy and receptor-mediated mitophagy in all models. Although mitochondrial content and dynamics appeared to be unaltered in response to CS, changes in both the molecular control of mitochondrial biogenesis and a shift toward an increased glycolytic metabolism were observed in particular in differentiated cultures. These alterations persisted, at least in part, after chronic exposure to WCS during differentiation and upon subsequent discontinuation of WCS exposure. In conclusion, smoke exposure alters the regulation of mitochondrial metabolism in airway epithelial cells, but observed alterations may differ between various culture models used. This article has an associated First Person interview with the joint first authors of the paper.

Effect of salvianolic acid B on NLRP3/caspase-1/GSDMD pyrolysis pathway in NASH cells

BACKGROUND

Numerous studies have proved that salvianolic acid B (Sal B) has a therapeutic effect on non-alcoholic fatty liver disease (NAFLD). Cell pyrolysis plays an important role in the onset of NAFLD and its progression to NASH. By studying the regulatory effect of Sal B on the main proteins related to cell pyrolysis in NASH, it was found that Sal B has the advantages of multiple approaches and multiple targets in the treatment of NAFLD.

AIM

To establish a non-alcoholic steatohepatitis (NASH) cell model by treating HepG2 cells with palmitic acid (PA), and explore the effect of Sal B on cell pyrolysis and the pyrolysis-related GSDMD/NLRP3/caspase-1 pathway.

METHODS

HepG2 cells in logarithmic growth phase were collected, and the optimal drug intervention concentration and intervention time for PA were assessed by MTT assay. The cells were randomly divided into a control group, a model group (PA), a treatment group (Sal B + PA), and a pyrolysis inhibitor group (VX-765 + PA). The cells of each group were stained with oil red O to observe the lipid accumulation in the cells under an inverted phase-contrast microscope. The cell supernatant was collected to measure the OD value with a microplate reader. The immunofluorescence probe DCFH-DA was used to determine the intracellular ROS content. The expression of interleukin 18 (IL-18) and interleukin 1β (IL-1β) in cell supernatant was determined by ELISA. The expression of NLRP3 and pyrolysis-related proteins caspase-1, GSDMD, and GSDMD-N was detected by Western blot.

RESULTS

Compared with the control group, the model group had obvious accumulation of lipids and ROS, increased secretion of inflammatory factors IL-1β and IL-18 (P < 0.05), and increased protein expression of NLRP3, caspase-1, GSDMD, and GSDMD-N (P < 0.05). Sal B or VX-765 inhibitor treatment can reverse the accumulation of lipids and ROS caused by PA, decreased the secretion of IL-1β and IL-18, and down-regulated the protein expression of NLRP3, caspase-1, GSDMD, and GSDMD-N (P < 0.05).

CONCLUSION

PA can induce pyrolysis of liver cells. Sal B can reduce inflammation and alleviate the progression of NASH by inhibiting the NLRP3/caspase-1/GSDMD pathway.

Screening and identification of dominant monoclonal HepG2 cell strain with 1.3-fold HBV genome

BACKGROUND

Hepatitis B virus (HBV) infection model in vitro is the basis for studying HBV life cycle and pathogenesis and for drug screening. With the clinical anti-HBV therapy entering the new trend of "functional cure" and "complete cure", there is an urgent need for cell models that can stably simulate the transcription mechanism of covalently closed circular DNA (cccDNA) and the role of hepatitis B virus X protein (HBx). The 1.3-fold HBV genome contains all the biological information of HBV. It can start the transcription process by its own promoter, support the formation of cccDNA, and complete viral replication, which is closest to the life cycle of HBV in vivo. Lentivirus transfection is a technology that takes lentivirus as vector and introduces foreign molecules such as DNA and RNA into eukaryotic cells, which can form stable transfection.

AIM

To construct a HepG2 cell model with 1.3-fold HBV genome by lentivirus transfection technology, and to screen and identify the dominant monoclonal strain that can stably and efficiently express HBV biomarkers.

METHODS

A lentiviral plasmid containing 1.3-fold HBV genome information was constructed, and the recombinant lentivirus culture was used to infect HepG2 cells at the optimal multiplicity of infection (MOI). Blasticidin (BSD) was used to select HepG2 cell strains (1.3-fold HBV-HepG2) stably integrating the 1.3-fold HBV genome, and then the HBV in the cell model was identified by PCR. HepG2 cells stably carrying the 1.3-fold HBV genome were cultured and nine candidate positive monoclones were selected. The flanking sequences of each monoclonal cell were sequenced to determine the insertion position of the corresponding HBV genome in the genome of HepG2 cells. The most dominant monoclones were selected according to the expression levels of HBsAg and HBeAg. The expression levels and stability of HBsAg, HBeAg, HBx, cccDNA, and HBV DNA in HepG2 cells stably carrying the 1.3-fold HBV genome were compared.

RESULTS

The lentiviral plasmid plenti-bsd-1.3-fold HBV was used to infect HepG2 cells at an MOI of 30. After 72 h, BSD (final concentration 1 μg/mL) was added for screening. After 15-20 d of continuous culture, stable 1.3-fold HBV-HepG2 cell line was obtained. HBV DNA sequence was then identified by PCR. Among the nine selected candidate positive monoclones, A14, in which the 1.3-fold HBV genome was inserted into the HepG2 genome at 1:166461695-166461715 (named HepGA14), had the highest expression levels of HBsAg and HBeAg at 24.28 IU/mL and 39.62 NCU/mL, respectively. HepGA14 can stably and highly express HBV biomarkers. Compared with HepG2.2.15 cell line, the expression levels of HBx and cccDNA in Hepga14 dominant monoclonal line in 1-20 passages were significantly higher (P < 0.05).

CONCLUSION

We have successfully constructed and screened HepGA14, a dominant monoclonal HepG cell strain with HBV 1.3-fold genome, which lays a good foundation for further research of HBV-host relationship and pathogenesis as well as for drug screening.

Neurospheres: a potential in vitro model for the study of central nervous system disorders

Neurogenesis was believed to end after the period of embryonic development. However, the possibility of obtaining an expressive number of cells with functional neuronal characteristics implied a great advance in experimental research. New techniques have emerged to demonstrate that the birth of new neurons continues to occur in the adult brain. Two main rich sources of these cells are the subventricular zone (SVZ) and the subgranular zone of the hippocampal dentate gyrus (SGZ) where adult neural stem cells (aNSCs) have the ability to proliferate and differentiate into mature cell lines. The cultivation of neurospheres is a method to isolate, maintain and expand neural stem cells (NSCs) and has been used extensively by several research groups to analyze the biological properties of NSCs and their potential use in injured brains from animal models. Throughout this review, we highlight the areas where this type of cell culture has been applied and the advantages and limitations of using this model in experimental studies for the neurological clinical scenario.

A cell model in the ventral visual pathway for the detection of circles of curvature constituting figures

The contour of an arbitrary figure can be represented as a group of circles of curvature in contact with it, with each curvature circle represented by its center O_C and radius r. We propose a series of cell models for detecting this circle, which is composed of a lateral geniculate nucleus (LGN) cell, nondirectionally selective (NDS) simple cell, and curvature-circle detection cell (CDC). The LGN and NDS simple cells were previously modeled. The CDC has been modeled as follows. Each tangent in contact with this circle is detected by an NDS simple cell that performs the Hough transformation of LGN cell responses, and then this tangent is transformed to a three-dimensional (3D) normal line in a CDC column. This transformation has been named a 3D normal-line transform. Performing this transformation for all tangents causes a CDC at the intersection of these normal lines to fire most intensively, and thus the O_C and r of the circle is detected as the coordinates of this intersection. Therefore, the CDC has been modeled as this 3D normal-line transform. Based on this CDC, we model two types of constancy CDC: a position-invariant CDC and a curvature-invariant CDC. These three types of CDC reflect the response to various stimuli in actual area V4 cells. In order to validate these CDC types neurophysiologically, we propose an experimental method using microelectrodes. Cell models previously reported correspond to this hierarchy: the S1, S2, and C2 cells correspond to the NDS simple cell, CDC, and position-invariant CDC, respectively.

Study on the hepatocellular carcinoma model with metastasis

Hepatocellular carcinoma (HCC) is one of the most common causes of cancer-related death around the world due to advanced clinical stage at diagnosis, high incidence of recurrence and metastasis after surgical treatment. It is in urgent need to create appropriate animal models to explore the mechanism, patterns, risk factors, and therapeutic strategies of HCC metastasis and recurrence. However, most of the established models lack the phenotype of invasion and metastasis in patient, or have unstable phenotype. To establish HCC models with stable metastasis phenotype requires profound understanding in cancer metastasis biology and scientific methodology. Over the past 3 decades, HCC models with stable metastasis have been extensively studied. This paper reviewed the history and development of HCC animal models and cell models, focusing on the screening and maintaining of metastatic potential and phenotype. In-depth studies using these models vastly promote the understanding of cellular and molecular mechanisms and development of therapeutic strategies on HCC metastasis.

Distribution modeling of nanoparticles for brachytherapy of human eye tumor

BACKGROUND

Due to their unique properties, gold nanoparticles (GNPs) have been proposed to be used for a wide range of applications, especially for photon radiation therapy. In addition to experimental works, there are worthwhile simulation-based studies focused on the investigation of the effect of parameters governing the dose enhancement due to the presence of GNPs in tissue. In a recently published study, we found that the distribution of GNPs in a single cell plays an important role in nucleus dose enhancement.

METHODS

The present work investigates the sensitivity of dose enhancement of a macroscopic phantom to the modeling of GNPs at the cellular level by using the MCNPX Monte Carlo code. A human eye phantom containing the realistic structures and materials was simulated, with a typical tumor located in its corner filled with three different patterns of distribution of GNPs around the nuclei of the cells. The primary photons emit from a COMS eye plaque brachytherapy containing thirteen ¹³¹Cs seeds in the vicinity of the tumor.

RESULTS

The study was extended to estimate dose enhancement for various concentration, size, and density of the GNPs accumulated around the nuclei of the tumor. Moreover, the dose delivered to the healthy eye structures for different models has been investigated and discussed. The results show obvious differences between the dose enhancements in the tumor depending on the modeling of GNPs.

CONCLUSION

The results emphasized that an appropriate small-scale model for the distribution of GNPs in the cell would be of high importance to estimate the degree of dose enhancement in a macroscopic phantom to provide a trustworthy prediction to move towards clinical application.

Protein profile of well-differentiated versus un-differentiated human bronchial/tracheal epithelial cells

Un-differentiated (UD) and well-differentiated (WD) normal human primary bronchial/tracheal epithelial cells are important respiratory cell models. Mature, WD cells which can be derived by culturing UD cells at an air-liquid interface represent a good surrogate for in vivo human airway epithelium. The overall protein profile of WD cells is poorly understood; therefore, the current study evaluated the proteomic characteristics of WD and UD cells using label-free LC-MS/MS and LC-PRM/MS. A total of 3,579 proteins were identified in WD and UD cells. Of these, 198 proteins were identified as differentially expressed, with 121 proteins upregulated and 77 proteins downregulated in WD cells compared with UD cells. Differentially expressed proteins were mostly enriched in categories related to epithelial structure formation, cell cycle, and immunity. Fifteen KEGG pathways and protein interaction networks were enriched and identified. The current study provides a global protein profile of WD cells, and contributes to understanding the function of human airway epithelium.

Suppression of Progranulin Expression Leads to Formation of Intranuclear TDP-43 Inclusions In Vitro: A Cell Model of Frontotemporal Lobar Degeneration

Mutations in the GRN gene coding for progranulin (PGRN) are responsible for many cases of familial frontotemporal lobar degeneration (FTLD) with TAR DNA-binding protein 43 (TDP-43)-positive inclusions (FTLD-TDP). GRN mutations create null alleles resulting in decreased progranulin protein or haploinsufficiency. FTLD-TDP with GRN mutations is characterized by lentiform neuronal intranuclear inclusions that are positive for TDP-43 in affected brain regions. In this study, by stably expressed short hairpin RNA, we established a neuroblastoma cell line with decreased PGRN level. This cell line reveals TDP-43-positive intranuclear inclusions. In addition, replacement with purified PGRN protein restores normal TDP-43 nuclear distribution. This cell model can be valuable for the study of the role of PGRN in the pathogenesis in FTLD-TDP.

Biological cells and coupled electro-mechanical effects: The role of organelles, microtubules, and nonlocal contributions

Biological cells are exposed to a variety of mechanical loads throughout their life cycles that eventually play an important role in a wide range of cellular processes. The understanding of cell mechanics under the application of external stimuli is important for capturing the nuances of physiological and pathological events. Such critical knowledge will play an increasingly vital role in modern medical therapies such as tissue engineering and regenerative medicine, as well as in the development of new remedial treatments. At present, it is well known that the biological molecules exhibit piezoelectric properties that are of great interest for medical applications ranging from sensing to surgery. In the current study, a coupled electro-mechanical model of a biological cell has been developed to better understand the complex behaviour of biological cells subjected to piezoelectric and flexoelectric properties of their constituent organelles under the application of external forces. Importantly, a more accurate modelling paradigm has been presented to capture the nonlocal flexoelectric effect in addition to the linear piezoelectric effect based on the finite element method. Major cellular organelles considered in the developed computational model of the biological cell are the nucleus, mitochondria, microtubules, cell membrane and cytoplasm. The effects of variations in the applied forces on the intrinsic piezoelectric and flexoelectric contributions to the electro-elastic response have been systematically investigated along with accounting for the variation in the coupling coefficients. In addition, the effect of mechanical degradation of the cytoskeleton on the electro-elastic response has also been quantified. The present studies suggest that flexoelectricity could be a dominant electro-elastic coupling phenomenon, exhibiting electric fields that are four orders of magnitude higher than those generated by piezoelectric effects alone. Further, the output of the coupled electro-mechanical model is significantly dependent on the variation of flexoelectric coefficients. We have found that the mechanical degradation of the cytoskeleton results in the enhancement of both the piezo and flexoelectric responses associated with electro-mechanical coupling. In general, our study provides a framework for more accurate quantification of the mechanical/electrical transduction within the biological cells that can be critical for capturing the complex mechanisms at cellular length scales.

The construction of in vitro nasal cavity-mimic M-cell model, design of M cell-targeting nanoparticles and evaluation of mucosal vaccination by nasal administration

In order to better evaluate the transport effect of nanoparticles through the nasal mucosa, an in vitro nasal cavity-mimic model was designed based on M cells. The differentiation of M cells was induced by co-culture of Calu-3 and Raji cells in invert model. The ZO-1 protein staining and the transport of fluorescein sodium and dexamethasone showed that the inverted co-culture model formed a dense monolayer and possessed the transport ability. The differentiation of M cells was observed by up-regulated expression of Sialyl Lewis A antigen (SLAA) and integrin β1, and down-regulated activity of alkaline phosphatase. After targeting M cells with iRGD peptide (cRGDKGPDC), the transport of nanoparticles increased. In vivo, the co-administration of iRGD could result in the increase of nanoparticles transported to the brain through the nasal cavity after intranasal administration. In the evaluation of immune effect in vivo, the nasal administration of OVA-PLGA/iRGD led to more release of IgG, IFN-γ, IL-2 and secretory IgA (sIgA) compared with OVA@PLGA group. Collectively, the study constructed in vitro M cell model, and proved the enhanced effect of targeting towards M cell with iRGD on improving nasal immunity.

SCN2A channelopathies in the autism spectrum of neuropsychiatric disorders: a role for pluripotent stem cells?

Efforts to identify the causes of autism spectrum disorders have highlighted the importance of both genetics and environment, but the lack of human models for many of these disorders limits researchers’ attempts to understand the mechanisms of disease and to develop new treatments. Induced pluripotent stem cells offer the opportunity to study specific genetic and environmental risk factors, but the heterogeneity of donor genetics may obscure important findings. Diseases associated with unusually high rates of autism, such as SCN2A syndromes, provide an opportunity to study specific mutations with high effect sizes in a human genetic context and may reveal biological insights applicable to more common forms of autism. Loss-of-function mutations in the SCN2A gene, which encodes the voltage-gated sodium channel Na_V1.2, are associated with autism rates up to 50%. Here, we review the findings from experimental models of SCN2A syndromes, including mouse and human cell studies, highlighting the potential role for patient-derived induced pluripotent stem cell technology to identify the molecular and cellular substrates of autism.

Modeling counter-current chromatography with non-ideal injection

In general counter-current chromatography systems, there are several off-column fittings between injector and column inlet, such as bends, valves, connecting tubes and joints. Due to these off-column fittings, the sample will diffuse in the mobile phase and form an irregular distribution when it flows from the injector to the column inlet. Thus, the concentration distribution of the solutes at the column inlet is a continuous curve (called the injection profile). As some previous research reveals, it is necessary to input actual injection profile into the simulation model to mimic elution profile. Therefore, we built a non-ideal CCC model whose initial value is from the actual injection profile, and validated the rationality of this model with iteration method. The simulation analysis of different injection profiles shows the conditions whereby a discrete injection profile can replace the actual injection profile in the non-ideal CCC model for accurate simulation elution. Simulation elution under such conditions reveal that non-ideal injection model can reflect the relationship between the injection profile and elution profile, and help to explain the reasons of irregular change in elution profile, like the tailed peak and flat peak.

Model-based approach for design and performance evaluation of works controlling stony debris flows with an application to a case study at Rovina di Cancia (Venetian Dolomites, Northeast Italy)

This paper proposes a methodology for the design and performance evaluation of debris-flow control works based on modeling the phenomenon and its interaction with the works. The reliability of such an approach depends on the trustworthy reproduction of both the phenomenon and its interaction with the structures: the former is provided by simulating all the physical processes concerning the phenomenon (runoff generation, initiation and propagation of a solid-liquid mixture) by models tested against field measurements; the latter by upgrading the propagation model for considering the non-erosive surfaces of the works overflowed or hit by debris flows and computing the forces exerted on them. This methodology is applied to a case study on the Rovina di Cancia channel (northeast Italy), frequently affected by stony debris flows. Longitudinal and transversal works are planned in a reach of the channel subject to high erosion because of its high slope and the supply of water discharge by the Bus de Diau Creek tributary. The works consist of a sectional dam at the end of the reach and in moving there the mouth of the Bus de Diau Creek. Both of them contribute to decrease bed erosion along the reach and to reduce the peak discharge and the transported sediment volume. The proposed methodology is used in the design phase to explore different geometries of the dam opening and choose its transversal position through the analysis of flow (velocity and free surface), whereas, in the evaluation phase, to estimate the reduction in the bed erosion, peak discharge and transported sediment volume provided by the works (i.e. the performance evaluation). Finally, the plot of the forces acting on the dam breakers and bottom over time allows their static dimensioning.

Enhanced differentiation of human dopaminergic neuronal cell model for preclinical translational research in Parkinson's disease

Human-derived neuronal cell lines are progressively being utilized in understanding neurobiology and preclinical translational research as they are biologically more relevant than rodent-derived cells lines. The Lund human mesencephalic (LUHMES) cell line comprises human neuronal cells that can be differentiated to post-mitotic neurons and is increasingly being used as an in vitro model for various neurodegenerative diseases. A previously published 2-step differentiation procedure leads to the generation of post-mitotic neurons within 5-days, but only a small proportion (10%) of the total cell population tests positive for tyrosine hydroxylase (TH). Here we report on a novel differentiation protocol that we optimized by using a cocktail of neurotrophic factors, pleiotropic cytokines, and antioxidants to effectively generate proportionately more dopaminergic neurons within the same time period. Visualization and quantification of TH-positive cells revealed that under our new protocol, 25% of the total cell population expressed markers of dopaminergic neurons with the TH-positive neuron count peaking on day 5. These neurons showed spontaneous electrical activity and responded to known Parkinsonian toxins as expected by showing decreased cell viability and dopamine uptake and a concomitant increase in apoptotic cell death. Together, our results outline an improved method for generating a higher proportion of dopaminergic neurons, thus making these cells an ideal neuronal culture model of Parkinson's disease (PD) for translational research.

Novel xanthine oxidase-based cell model using HK-2 cell for screening antihyperuricemic functional compounds

Hyperuricemia is a metabolic disease caused by disorders of purine metabolism, the prevalence of which has increased worldwide. Here, a cell model for high uric acid production was established in vitro employing cultured human kidney cells (HK-2 cells), and its molecular basis was analyzed using gene expression profile. High performance liquid chromatography (HPLC) was used to monitor the content of metabolites in cell culture media. Adenosine addition was found to induce HK-2 cells to produce uric acid precursors (inosine and hypoxanthine). Furthermore, the cell model was verified by confirming the antihyperuricemic effect of the widely used antihyperuricemic drugs allopurinol, probenecid, and febuxostat, as well as reported bioactive peptides and amino acids, encompassing glutathione, tryptophan and carnosine, which significantly reduced uric acid production in the HK-2 cells (p < 0.05). RNA-Seq technology was used to perform a wide transcriptome analysis of the hyperuricemic cell model, and the results demonstrated that it has the potential to be used as a rapid and valid in vitro model to screen antihyperuricemic compounds that mimics in vivo cell growth patterns.

Using Cell Cultures for the Investigation of Treatments for Attention Deficit Hyperactivity Disorder: A Systematic Review

Background:

Advances in basic and molecular biology have promoted the use of cell cultures in a wide range of areas, including the evaluation of drug efficacy, safety and toxicity.

Objective:

This article aims to provide a general overview of the methodological parameters of cell cultures used to investi-gate therapeutic options for Attention Deficit Hyperactivity Disorder.

Method:

A systematic search was performed in the electronic databases PubMed, Scopus, and DOAJ. In vitro experimental studies using cell cultures were included.

Results:

A total of 328 studies were initially identified, with 16 included for qualitative synthesis. Seven studies used neu-ronal cells (SH-SY5Y neuroblastoma and PC12 cell line) and nine used non-neuronal cells. All the studies described the cul-ture conditions, but most studies were inconsistent with regard to reporting results and raw data. Only one-third of the stud-ies performed cell viability assays, while a further 30% conducted gene expression analysis. Other additional tests included electrophysiological evaluation and transporter activity. More than 50% of the studies evaluated the effects of drugs such as methylphenidate and atomoxetine, while plant extracts were assessed in four studies and polyunsaturated fatty acids in one.

Conclusion:

We suggested a flowchart to guide the planning and execution of studies, and a checklist to be completed by authors to allow the standardized reporting of results. This may guide the elaboration of laboratory protocols and further in vitro studies.

Simultaneous quantitation of 14 DNA alkylation adducts in human liver and kidney cells by UHPLC-MS/MS: Application to profiling DNA adducts of genotoxic reagents

A rapid, sensitive and wide coverage ultra-high-performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS) method has been developed and validated for the simultaneous quantitation of 14 alkylation DNA adducts in cell genomic DNA, RNA and cell contents isolated from the in vitro cultured human kidney cell line 293 T and the human liver cell line L02 exposed to 3 genotoxic reagents: N-methyl-N-nitrosourea (MNU), methyl methanesulfonate (MMS) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). After exposure, DNA was isolated and directly hydrolysed under acid conditions or digested by enzymes to obtain the hydrolysates containing DNA alkylation adducts followed by optimization of the pretreatment method and chromatographic separation conditions. Quantification was performed on a Waters ACQUITY UPLC BEH Amide column (1.7 μm, 2.1 × 150 mm) using an electrospray ionization (ESI) source in positive mode by selective reaction monitoring (SRM) at the precursor to product ion transitions of 14 analytes. The method showed selectivity, good linearity (r＞0.9950), accuracy (82.1%-115%), and intra-day (RSD%＜14%) and inter-day (RSD%＜15%) precision for 14 analytes. The recoveries of two pretreatment methods were all more than 50.5%, and no relative matrix effects were observed. Additionally, the samples were stable after short-term storage at 20 ℃ for 2 h, at 4 ℃ for 48 h or one cycle of freeze-thaw at -80 ℃. The established UHPLC-MS/MS method was used to evaluate the changes in alkylation DNA adducts and epigenetic modification-related methylcytosine after exposure to genotoxic reagents. For the first time, the results demonstrated that 3 genotoxic reagents induced different total amounts of adducts in the following sequence: MMS ＞ NNK ＞ MNU, and showed significant differences in the ratios of 7MeG to 1MeA and 1MeG to 1MeA in the 293 T cell model. Meanwhile, 293 T and L02 cells revealed significantly different DNA adduct formation characteristics in the contents of 1MeG and 1MeA. The DNA adduct formation relationships between DNA, RNA, and cell contents were probed to predict cancer risk and potential genotoxic exposure. This approach could be used to investigate the DNA adducts, their formation and the relationship to the mutagenicity or carcinogenicity of genotoxic reagents in future studies.

The Use of Primary Hepatocytes in Assessment of Drug Safety and Toxicity

The identification of biomarkers for toxicity is becoming increasingly important for drug discovery and development. This chapter describes the preparation and utilization of primary rat hepatocytes as a cellular model of steatosis. A protocol is presented for dosing the cells with the steatosis-inducing compound amiodarone, along with the conduction of assays for measuring lipid accumulation and mitochondrial function. A differential solubility extraction procedure is also presented, which can be used for proteomic profiling analysis.

Molecular Characterization of Human Leukemia 60 (HL-60) Cells as a Model of Acute Myelogenous Leukemia Post Cryopreservation

The use of human leukemic (HL)-60 cells is important for studies of acute myeloid leukemia (AML) and as a model system for investigating how specific types of blood cells are formed during the process of hematopoiesis. Here, we present a protocol for growth of HL-60 cells along with molecular and functional profiles associated with their cryostorage. We also elucidate the effects of these procedures on cell viability and functions. This method can be used to provide biomarkers as readouts for testing the efficacy and/or toxicity of novel compounds in AML research as well as in a number of other experimental manipulations.

Dynamic viscosity of colloidal silica suspensions at low and high volume fractions

A comprehensive study was carried out on the dynamic viscosity of X30 silica dispersions at both high and low volume fractions of colloidal silica particles at various electrolyte ionic strength and pH values. Booth and Ruiz-Reina and Carrique theoretical models (R-R&C) were compared in predicting the primary electroviscous effect (PEE) for viscosity at low volume fractions. To this respect the colloidal dispersion was well characterised with regards to electrolyte properties such as the Debye length, κ^-1, calculated from the ionic strength, and zeta potential, ζ, calculated from the electrophoretic mobility using the full numerical model by O'Brien and White (O'B&W). R-R&C hard sphere model (which is a modified version of Simha hard sphere model that includes a boundary condition by Happel on the outer radius of the cell) and the semi-empirical Krieger-Dougherty (K-D) models were fitted to the experimental data at high volume fractions. At both low and high volume fractions the viscosity increased with pH and decreased with ionic strength. At low volume fractions both theoretical models significantly underestimated the experimental dynamic viscosities obtained in this work. This could be attributed to the fuzzy structures for silica particles in aqueous conditions reported previously in the literature, where a significantly larger electroviscous parameter, p, was obtained experimentally for silica particles. The experimental electroviscous parameter, p_exp, in this work was found to be roughly an order of magnitude up to 26 times larger than that predicted by Booth and around 5 ± 1 times larger than the predicted p by R-R&C model allowing the introduction of a correction factor in the PEE coefficient obtained from R-R&C model enabling good prediction for X30 silica dispersions by the latter model. The significant improvement of the electroviscous effect predictions by R-R&C model compared to Booth model may be attributed to the limitations invalidating the Booth model at the electrolyte conditions in this study. At high volume fractions, the R-R&C hard sphere cell model, gave a much better fit to the experimental data compared to the K-D model, which also had the advantage of being only dependent on a coefficient that linearly relates an effective volume fraction postulated for the fuzzy silica particles to the experimental. The K-D model however, depends on the intrinsic viscosity, [η], which requires the calculation of the experimental slope of the dynamic viscosity against volume fraction in the dilute limit, and also on a maximum packing fraction as a fitting parameter. Due to the effect of the fuzzy structures on the viscosity, the latter effective volume fraction ϕ_eff was calculated using two approaches: (i) as a fitting parameter by fitting the R-R&C hard sphere model to the experimental viscosity data over the entire volume fraction range, and (ii) by fitting only the linear part of the experimental viscosity at low volume fractions, It is concluded that the R-R&C hard sphere model with the effective volume fraction accounting for the fuzzy structures fits reasonably well the full range of experimental results at low and high volume fractions. When the model was used with the Adamczyk effective volume fraction (i.e., considering only the dilute region in the fitting procedure), the predictions became worse at high volume fractions where significant deviations from the experimental results were found upon the increase of pH.

Long-term and mechanistic evaluation of drug-induced liver injury in Upcyte human hepatocytes

Drug-induced liver injury (DILI) constitutes one of the most frequent reasons of restricted-use warnings as well as withdrawals of drugs in postmarketing and poses an important concern for the pharmaceutical industry. The current hepatic in vivo and in vitro models for DILI detection have shown clear limitations, mainly for studies of long-term hepatotoxicity. For this reason, we here evaluated the potential of using Upcytes human hepatocytes (UHH) for repeated-dose long-term exposure to drugs. The UHH were incubated with 15 toxic and non-toxic compounds for up to 21 days using a repeated-dose approach, and, in addition to conventional examination of effects on viability, the mechanisms implicated in cell toxicity were also assessed by means of high-content screening. The UHH maintained the expression and activity levels of drug-metabolizing enzymes for up to 21 days of culture and became more sensitive to the toxic compounds after extended exposures, showing inter-donor differences which would reflect variability among the population. The assay also allowed to detect the main mechanisms implicated in the toxicity of each drug as well as identifying special susceptibilities depending on the donor. UHH can be used for a long-term repeated detection of DILI at clinically relevant concentrations and also offers key mechanistic features of drug-induced hepatotoxicity. This system is therefore a promising tool in preclinical testing of human relevance that could help to reduce and/or replace animal testing for drug adverse effects.

Suppressing Tau Aggregation and Toxicity by an Anti-Aggregant Tau Fragment

Tau aggregation is a hallmark of a group of neurodegenerative diseases termed Tauopathies. Reduction of aggregation-prone Tau has emerged as a promising therapeutic approach. Here, we show that an anti-aggregant Tau fragment (F3^ΔKPP, residues 258–360) harboring the ΔK280 mutation and two proline substitutions (I²⁷⁷P & I³⁰⁸P) in the repeat domain can inhibit aggregation of Tau constructs in vitro, in cultured cells and in vivo in a Caenorhabditis elegans model of Tau aggregation. The Tau fragment reduced Tau-dependent cytotoxicity in a N2a cell model, suppressed the Tau-mediated neuronal dysfunction and ameliorated the defective locomotion in C. elegans. In vitro the fragment competes with full-length Tau for polyanionic aggregation inducers and thus inhibits Tau aggregation. Our combined in vitro and in vivo results suggest that the anti-aggregant Tau fragment may potentially be used to address the consequences of Tau aggregation in Tauopathies.

Human cellular models of medium spiny neuron development and Huntington disease

The loss of gamma-aminobutyric acid (GABA)-ergic medium spiny neurons (MSNs) in the striatum is the hallmark of Huntington disease (HD), an incurable neurodegenerative disorder characterized by progressive motor, psychiatric, and cognitive symptoms. Transplantation of MSNs or their precursors represents a promising treatment strategy for HD. In initial clinical trials in which HD patients received fetal neurografts directly into the striatum without a pretransplant cell-differentiation step, some patients exhibited temporary benefits. Meanwhile, major challenges related to graft overgrowth, insufficient survival of grafted cells, and limited availability of donated fetal tissue remain. Thus, the development of approaches that allow modeling of MSN differentiation and HD development in cell culture platforms may improve our understanding of HD and translate, ultimately, into HD treatment options. Here, recent advances in the in vitro differentiation of MSNs derived from fetal neural stem cells/progenitor cells (NSCs/NPCs), embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs), and induced NSCs (iNSCs) as well as advances in direct transdifferentiation are reviewed. Progress in non-allele specific and allele specific gene editing of HTT is presented as well. Cell characterization approaches involving phenotyping as well as in vitro and in vivo functional assays are also discussed.

Experimental Verification of the Elastic Formula for the Aspirated Length of a Single Cell Considering the Size and Compressibility of Cell During Micropipette Aspiration

In this study, an aspiration system for elastic spheres was developed to verify the approximate elastic formula for the aspirated length of a single solid-like cell undergoing micropipette aspiration (MPA), which was obtained in our previous study by theoretical analysis and numerical simulation. Using this system, foam silicone rubber spheres with different diameters and mechanical properties were aspirated in a manner similar to the MPA of single cells. Comparisons between the approximate elastic formula and aspiration experiments of spheres indicated that the predictions of the formula agreed with the experimental results. Additionally, combined with the MPA data of rabbit chondrocytes, differences in terms of the elastic parameters derived from the half-space model, incompressible sphere model, and compressible sphere model were explored. The results demonstrated that the parameter ξ (ξ = R/a, where R is the radius of the cell and a is the inner radius of the micropipette) and Poisson's ratio significantly influenced the determination of the elastic modulus and bulk modulus of the cell. This work developed for the first time an aspiration system of elastic spheres to study the elastic responses of the MPA of a single cell and provided new evidence supporting the use of the approximate elastic formula to determine cellular elastic parameters from the MPA data.

A new Alzheimer's disease cell model using B cells to induce beta amyloid plaque formation and increase TNF alpha expression

Different cell models have been developed for the study of Alzheimer's disease (AD) pathways. The neuronal dysfunction and cell death mechanisms that are commonly found in this disease are due to the production of high levels of cytokines and the formation of amyloid plaques. In the cell model introduced in the present study, the production of these two important factors is induced by using B cells from an AD patient. The B cells of an Alzheimer's patient and a normal control were immortalized by using EBV (Epstein-Barr virus) to produce a lymphoblastoid cell line (LCL). The amount of TNF alpha cytokine was evaluated at the RNA and protein levels by RT-PCR and ELISA, respectively. The AD LCL was cultured with SKNMC cells with and without treatment of TNF alpha siRNA. Amyloid plaque formation was monitored by Congo-red staining and microscopy. The amount of TNF alpha cytokine was significantly increased in the AD LCL compared to the normal LCL. The AD LCL induced the formation of amyloid plaques in SKNMC cells. The AD LCL treated with TNF alpha siRNA and co-cultured with SKNMC cells decreased the size and number of amyloid plaques in SKNMC cells. This cellular model is an appropriate model for studying Alzheimer's disease and the mechanisms related to it, as well as for research on cytokine inhibitors, especially TNF alpha inhibitors.

Studies of Isolated Peripheral Blood Cells as a Model of Immune Dysfunction

Peripheral blood mononuclear cells (PBMCs) have been used as a surrogate model of immune function in studies of multiple medical areas, such as metabolic diseases and immune dysfunction. This chapter describes a standardized technique for blood draw and preparation of PBMCs from whole blood using density gradient centrifugation, followed by cell culture. The main focus is on collection of the PBMC culture media and extraction of cellular proteins in order to provide the materials for biomarker studies.

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.

Customised in vitro model to detect human metabolism-dependent idiosyncratic drug-induced liver injury

Drug-induced liver injury (DILI) has a considerable impact on human health and is a major challenge in drug safety assessments. DILI is a frequent cause of liver injury and a leading reason for post-approval drug regulatory actions. Considerable variations in the expression levels of both cytochrome P450 (CYP) and conjugating enzymes have been described in humans, which could be responsible for increased susceptibility to DILI in some individuals. We herein explored the feasibility of the combined use of HepG2 cells co-transduced with multiple adenoviruses that encode drug-metabolising enzymes, and a high-content screening assay to evaluate metabolism-dependent drug toxicity and to identify metabolic phenotypes with increased susceptibility to DILI. To this end, HepG2 cells with different expression levels of specific drug-metabolism enzymes (CYP1A2, CYP2B6, CYP2C9, CYP2C19, CYP2D6, CYP2E1, CYP3A4, GSTM1 and UGT2B7) were exposed to nine drugs with reported hepatotoxicity. A panel of pre-lethal mechanistic parameters (mitochondrial superoxide production, mitochondrial membrane potential, ROS production, intracellular calcium concentration, apoptotic nuclei) was used. Significant differences were observed according to the level of expression and/or the combination of several drug-metabolism enzymes in the cells created ad hoc according to the enzymes implicated in drug toxicity. Additionally, the main mechanisms implicated in the toxicity of the compounds were also determined showing also differences between the different types of cells employed. This screening tool allowed to mimic the variability in drug metabolism in the population and showed a highly efficient system for predicting human DILI, identifying the metabolic phenotypes associated with increased DILI risk, and indicating the mechanisms implicated in their toxicity.

Lipidomic profiling of patient-specific iPSC-derived hepatocyte-like cells

Hepatocyte-like cells (HLCs) differentiated from human induced pluripotent stem cells (iPSCs) offer an alternative model to primary human hepatocytes to study lipid aberrations. However, the detailed lipid profile of HLCs is yet unknown. In the current study, functional HLCs were differentiated from iPSCs generated from dermal fibroblasts of three individuals by a three-step protocol through the definitive endoderm (DE) stage. In parallel, detailed lipidomic analyses as well as gene expression profiling of a set of lipid-metabolism-related genes were performed during the entire differentiation process from iPSCs to HLCs. Additionally, fatty acid (FA) composition of the cell culture media at different stages was determined. Our results show that major alterations in the molecular species of lipids occurring during DE and early hepatic differentiation stages mainly mirror the quality and quantity of the FAs supplied in culture medium at each stage. Polyunsaturated phospholipids and sphingolipids with a very long FA were produced in the cells at a later stage of differentiation. This work uncovers the previously unknown lipid composition of iPSC-HLCs and its alterations during the differentiation in conjunction with the expression of key lipid-associated genes. Together with biochemical, functional and gene expression measurements, the lipidomic analyses allowed us to improve our understanding of the concerted influence of the exogenous metabolite supply and cellular biosynthesis essential for iPSC-HLC differentiation and function. Importantly, the study describes in detail a cell model that can be applied in exploring, for example, the lipid metabolism involved in the development of fatty liver disease or atherosclerosis.

Modelling Human Colonic Smooth Muscle Cell Electrophysiology

The colon is a digestive organ that is subject to a wide range of motility disorders. However, our understanding of the etiology of these disorders is far from complete. In this study, a quantitative single cell model has been developed to describe the electrical behaviour of a human colonic smooth muscle cell (hCSMC). This model includes the pertinent ionic channels and intracellular calcium homoeostasis. These components are believed to contribute significantly to the electrical response of the hCSMC during a slow wave. The major ion channels were constructed based on published data recorded from isolated human colonic myocytes. The whole cell model is able to reproduce experimentally recorded slow waves from human colonic muscles. This represents the first biophysically-detailed model of a hCSMC and provides a means to better understand colonic disorders.

Cellular models to study schizophrenia: A systematic review

BACKGROUND

Advancements in cellular reprogramming techniques have made it possible to directly study brain cells from patients with neuropsychiatric disorders. We have systematically reviewed the applications of induced pluripotent stem cells (IPSCs) and their neural derivatives in understanding the biological basis of schizophrenia.

METHOD

We searched the scientific literature published in MEDLINE with the following search strategy: (Pluripotent) AND (Schizophrenia OR Antipsychotic OR Psychosis). Studies written in English that used IPSCs derived from patients with schizophrenia were included.

RESULTS

Out of 23 articles, which had used IPSCs from patients with schizophrenia, neurons or neural stem cells had been derived from them in a majority. Several parameters had been studied; the key cellular phenotypes identified included those of synaptic pathology, neural migration/proliferation deficits, and abnormal oxidative phosphorylation.

CONCLUSION

Cellular modelling using IPSCs could improve the biological understanding of schizophrenia. Emerging findings are consistent with those of other study designs (post-mortem brain expression, animal studies, genome-wide association, brain imaging). Future studies should focus on refined study designs (family-based, pharmacogenomics, gene editing) and a combination of cellular studies with deep clinical phenotyping.

A Natural Model of Mouse Cardiac Myocyte Senescence

Many cardiac aging studies are performed on mice first and then, due to difficulty in mouse cardiomyocyte culture, applied the rat neonatal cardiomyocytes to further determine the mechanisms in vitro. Now, the technological challenge of mouse cardiomyocyte culture has been overcome and there is an increasing need for the senescence models of mouse cardiomyocytes. In this study, we have demonstrated that the senescence of mouse cardiomyocytes occurred with the extended culture time as shown by the increased β-galactosidase staining, increased p53 expression, decreased telomere activity, shorted telomere length, increased production of ROS, increased cell apoptosis, and impaired mitochondrial ΔΨm. These senescent responses shared similar results in aged mouse heart tissues in vivo. In summary, we have established and characterized a novel senescence model of mouse cardiomyocytes induced by the extended culture time in vitro. The cell model could be useful for the increased cardiac aging studies worldwide.

X/XO or H2O2 induced IPEC-J2 cell as a new in vitro model for studying apoptosis in post-weaning piglets

We previously demonstrated that intestinal epithelial cell apoptosis in weaned piglets is much more serious than that observed in sucking piglets and is related to oxidative stress during weaning. It is difficult to study the apoptosis mechanisms only using in vivo methods because of the limit of existing research technology. An in vitro cellular system is required for piglet intestinal epithelial cell apoptosis research. In this study, a non-tumorigenic epithelial cell line, IPEC-J2 cells, was employed as a cell model. Hydrogen peroxide and xanthine/xanthine oxidase (X/XO) were both used and compared for apoptosis modeling. The concentrations of hydrogen peroxide and XO were selected and verified using cell viability analysis, the comet assay and flow cytometry. Intracellular ROS were measured using fluorescent probes. Additionally, the expression levels of the apoptosis-related genes Fas, Bcl-2, P53, Caspase 3, Caspase 8, and Caspase 9 were analyzed using quantitative RT-PCR. The results indicated the optimal modeling method is a final concentration of 0.5 mM H2O2 incubated with IPEC-J2 cells for 1 h at 37 °C in 5 % CO2 for hydrogen peroxide-induced apoptosis modeling, and a final concentration of 250 μM X/50 U/L XO incubated with IPEC-J2 cells for 6 h at 37 °C in 5 % CO2 for X/XO-induced apoptosis modeling. For the apoptotic pathway, the X/XO modeling method is more similar to 21 days weaning piglets. Therefore, we suggest that X/XO modeling with IPEC-J2 cells be used as an in vitro cell culture model for weaning piglet intestinal epithelial cell apoptosis.

How do the physicochemical properties of nanoliposomes affect their interactions with the hCMEC/D3 cellular model of the BBB?

Nanosized liposomes composed of 1,2-distearoyl-sn-glycerol-3-phosphatidylcholine (DSPC), cholesterol and polyethylene glycol-conjugated phospholipid (PEG), incorporating FITC-dextran (FITC) and in some cases also Rhodamine-conjugated phospholipid (RHO) (as labels) were constructed by the thin film hydration method, followed by extrusion; membranes with pore diameters from 50 to 400nm were used, while charged vesicles were produced by partially replacing DSPC with 1,2-distearoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (DSPG). The uptake of liposomes by hCMED/D3 cells was evaluated by measuring FITC in cells, and their permeability across cell monolayers was evaluated, by measuring the FI of liposome associated-FITC and RHO in the receiving side of a monolayer-transwell system. Results prove that liposome size has a significant effect on their uptake and permeability (for both charged and non-charged vesicles). The effect of liposome charge on cell uptake was slight (but significant), however charge (in the range from -2 to -16mV) did not significantly affect vesicle permeability; a significant decrease was only demonstrated for the liposome with the highest charge.

Use of human stem cells in Huntington disease modeling and translational research

Huntington disease (HD) is a devastating neurological disorder caused by an extended CAG repeat in exon 1 of the gene that encodes the huntingtin (HTT) protein. HD pathology involves a loss of striatal medium spiny neurons (MSNs) and progressive neurodegeneration affects the striatum and other brain regions. Because HTT is involved in multiple cellular processes, the molecular mechanisms of HD pathogenesis should be investigated on multiple levels. On the cellular level, in vitro stem cell models, such as induced pluripotent stem cells (iPSCs) derived from HD patients and HD embryonic stem cells (ESCs), have yielded progress. Approaches to differentiate functional MSNs from ESCs, iPSCs, and neural stem/progenitor cells (NSCs/NPCs) have been established, enabling MSN differentiation to be studied and disease phenotypes to be recapitulated. Isolation of target stem cells and precursor cells may also provide a resource for grafting. In animal models, transplantation of striatal precursors differentiated in vitro to the striatum has been reported to improve disease phenotype. Initial clinical trials examining intrastriatal transplantation of fetal neural tissue suggest a more favorable clinical course in a subset of HD patients, though shortcomings persist. Here, we review recent advances in the development of cellular HD models and approaches aimed at cell regeneration with human stem cells. We also describe how genome editing tools could be used to correct the HTT mutation in patient-specific stem cells. Finally, we discuss the potential and the remaining challenges of stem cell-based approaches in HD research and therapy development.

Regulatory effects on the population dynamics and wave propagation in a cell lineage model

We consider the interplay of cell proliferation, cell differentiation (and de-differentiation), cell movement, and the effect of feedback regulations on the population and propagation dynamics of different cell types in a cell lineage model. Cells are assumed to secrete and respond to negative feedback molecules which act as a control on the cell lineage. The cell densities are described by coupled reaction-diffusion partial differential equations, and the propagating wave front solutions in one dimension are investigated analytically and by numerical solutions. In particular, wavefront propagation speeds are obtained analytically and verified by numerical solutions of the equations. The emphasis is on the effects of the feedback regulations on different stages in the cell lineage. It is found that when the progenitor cell is negatively regulated, the populations of the cell lineage are strongly down-regulated with the steady growth rate of the progenitor cell being driven to zero beyond a critical regulatory strength. An analytic expression for the critical regulation strength in terms of the model parameters is derived and verified by numerical solutions. On the other hand, if the inhibition is acting on the differentiated cells, the change in the population dynamics and wave propagation speed is small. In addition, it is found that only the propagating speed of the progenitor cells is affected by the regulation when the diffusion of the differentiated cells is large. In the presence of de-differentiation, the effect on down-regulating the progenitor population is weakened and there is no effect on the propagation speed due to regulation, suggesting that the effect of regulatory control is diminished by de-differentiation pathways.