FEZ1 participates in human embryonic brain development by modulating neuronal progenitor subpopulation specification and migrations.

Mutations in the human fasciculation and elongation protein zeta 1 (FEZ1) gene are found in schizophrenia and Jacobsen syndrome patients. Here, using human cerebral organoids (hCOs), we show that FEZ1 expression is turned on early during brain development and is detectable in both neuroprogenitor subtypes and immature neurons. FEZ1 deletion disrupts expression of neuronal and synaptic development genes. Using single-cell RNA sequencing, we detected abnormal expansion of homeodomain-only protein homeobox (HOPX)- outer radial glia (oRG), concurrent with a reduction of HOPX+ oRG, in FEZ1-null hCOs. HOPX- oRGs show higher cell mobility as compared to HOPX+ oRGs. Ectopic localization of neuroprogenitors to the outer layer is seen in FEZ1-null hCOs. Anomalous encroachment of TBR2+ intermediate progenitors into CTIP2+ deep layer neurons further indicated abnormalities in cortical layer formation these hCOs. Collectively, our findings highlight the involvement of FEZ1 in early cortical brain development and how it contributes to neurodevelopmental disorders.

The importance of fasciculation and elongation protein zeta-1 in neural circuit establishment and neurological disorders.

The human brain contains an estimated 100 billion neurons that must be systematically organized into functional neural circuits for it to function properly. These circuits range from short-range local signaling networks between neighboring neurons to long-range networks formed between various brain regions. Compelling converging evidence indicates that alterations in neural circuits arising from abnormalities during early neuronal development or neurodegeneration contribute significantly to the etiology of neurological disorders. Supporting this notion, efforts to identify genetic causes of these disorders have uncovered an over-representation of genes encoding proteins involved in the processes of neuronal differentiation, maturation, synaptogenesis and synaptic function. Fasciculation and elongation protein zeta-1, a Kinesin-1 adapter, has emerged as a key central player involved in many of these processes. Fasciculation and elongation protein zeta-1-dependent transport of synaptic cargoes and mitochondria is essential for neuronal development and synapse establishment. Furthermore, it acts downstream of guidance cue pathways to regulate axo-dendritic development. Significantly, perturbing its function causes abnormalities in neuronal development and synapse formation both in the brain as well as the peripheral nervous system. Mutations and deletions of the fasciculation and elongation protein zeta-1 gene are linked to neurodevelopmental disorders. Moreover, altered phosphorylation of the protein contributes to neurodegenerative disorders. Together, these findings strongly implicate the importance of fasciculation and elongation protein zeta-1 in the establishment of neuronal circuits and its maintenance.

Hepatic spheroids used as an in vitro model to study malaria relapse.

Hypnozoites are the liver stage non-dividing form of the malaria parasite that are responsible for relapse and acts as a natural reservoir for human malaria Plasmodium vivax and P. ovale as well as a phylogenetically related simian malaria P. cynomolgi. Our understanding of hypnozoite biology remains limited due to the technical challenge of requiring the use of primary hepatocytes and the lack of robust and predictive in vitro models. In this study, we developed a malaria liver stage model using 3D spheroid-cultured primary hepatocytes. The infection of primary hepatocytes in suspension led to increased infectivity of both P. cynomolgi and P. vivax infections. We demonstrated that this hepatic spheroid model was capable of maintaining long term viability, hepatocyte specific functions and cell polarity which enhanced permissiveness and thus, permitting for the complete development of both P. cynomolgi and P. vivax liver stage parasites in the infected spheroids. The model described here was able to capture the full liver stage cycle starting with sporozoites and ending in the release of hepatic merozoites capable of invading simian erythrocytes in vitro. Finally, we showed that this system can be used for compound screening to discriminate between causal prophylactic and cidal antimalarials activity in vitro for relapsing malaria.

A Descriptive Qualitative Study of Home Care Experiences in Parents of Children with Tracheostomies.

PURPOSE: The number of pediatric patients who require a long-term tracheal tube at home is gradually increasing. Studies have demonstrated that the parents of these children report high levels of stress, anxiety and other negative emotions as early as shortly after discharge from the hospital. The purpose of this study is to describe the home care experiences of parents of children with tracheostomies during the transition from hospital to home in China to more effectively address their needs. DESIGN AND METHODS: This study used a qualitative descriptive design and face-to-face interviews with semi-structured questions to learn about the home care experiences of parents whose children had undergone a tracheostomy. RESULTS: Thirteen parents were recruited from the otorhinolaryngology outpatient ward of Xinhua Hospital in Shanghai, China. These parents described three categories of home care experiences: "direct care overload," "psychological overload," and "personal growth." Subcategories included parental "role change," "from helplessness to skillfulness," "lack of professional support," "anxiety and depression," and "social isolation." They also reported personal growth, which was mainly reflected by "changing their perspectives" and "developing potential." CONCLUSION: Although the findings of this study indicate that the physical and psychological overload reported by parents of children with tracheostomies during home care is inevitable, a better understanding of parents' caring experiences among professionals may facilitate clinical practice and promote continued community nursing care in China. PRACTICE IMPLICATIONS: Parents hope to receive systematic education during hospitalization, including web-based video education for skills training after discharge. In addition, parents desire public recognition so that they can participate in normal family and community activities.

On chip two-photon metabolic imaging for drug toxicity testing.

We have developed a microfluidic system suitable to be incorporated with a metabolic imaging method to monitor the drug response of cells cultured on a chip. The cells were perfusion-cultured to mimic the blood flow in vivo. Label-free optical measurements and imaging of nicotinamide adenine dinucleotide and flavin adenine dinucleotide fluorescence intensity and morphological changes were evaluated non-invasively. Drug responses calculated using redox ratio imaging were compared with the drug toxicity testing results obtained with a traditional well-plate system. We found that our method can accurately monitor the cell viability and drug response and that the IC50 value obtained from imaging analysis was sensitive and comparable with a commonly used cell viability assay: MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfo-phenyl)-2H-tetrazolium) assay. Our method could serve as a fast, non-invasive, and reliable way for drug screening and toxicity testing as well as enabling real-time monitoring of in vitro cultured cells.

Patient-specific hepatocyte-like cells derived from induced pluripotent stem cells model pazopanib-mediated hepatotoxicity.

Idiosyncratic drug-induced hepatotoxicity is a major cause of liver damage and drug pipeline failure, and is difficult to study as patient-specific features are not readily incorporated in traditional hepatotoxicity testing approaches using population pooled cell sources. Here we demonstrate the use of patient-specific hepatocyte-like cells (HLCs) derived from induced pluripotent stem cells for modeling idiosyncratic hepatotoxicity to pazopanib (PZ), a tyrosine kinase inhibitor drug associated with significant hepatotoxicity of unknown mechanistic basis. In vitro cytotoxicity assays confirmed that HLCs from patients with clinically identified hepatotoxicity were more sensitive to PZ-induced toxicity than other individuals, while a prototype hepatotoxin acetaminophen was similarly toxic to all HLCs studied. Transcriptional analyses showed that PZ induces oxidative stress (OS) in HLCs in general, but in HLCs from susceptible individuals, PZ causes relative disruption of iron metabolism and higher burden of OS. Our study establishes the first patient-specific HLC-based platform for idiosyncratic hepatotoxicity testing, incorporating multiple potential causative factors and permitting the correlation of transcriptomic and cellular responses to clinical phenotypes. Establishment of patient-specific HLCs with clinical phenotypes representing population variations will be valuable for pharmaceutical drug testing.

Functionally Enhanced Human Stem Cell Derived Hepatocytes in Galactosylated Cellulosic Sponges for Hepatotoxicity Testing.

Pluripotent stem cell derived hepatocyte-like cells (hPSC-HLCs) are an attractive alternative to primary human hepatocytes (PHHs) used in applications ranging from therapeutics to drug safety testing studies. It would be critical to improve and maintain mature hepatocyte functions of the hPSC-HLCs, especially for long-term studies. If 3D culture systems were to be used for such purposes, it would be important that the system can support formation and maintenance of optimal-sized spheroids for long periods of time, and can also be directly deployed in liver drug testing assays. We report the use of 3-dimensional (3D) cellulosic scaffold system for the culture of hPSC-HLCs. The scaffold has a macroporous network which helps to control the formation and maintenance of the spheroids for weeks. Our results show that culturing hPSC-HLCs in 3D cellulosic scaffolds increases functionality, as demonstrated by improved urea production and hepatic marker expression. In addition, hPSC-HLCs in the scaffolds exhibit a more mature phenotype, as shown by enhanced cytochrome P450 activity and induction. This enables the system to show a higher sensitivity to hepatotoxicants and a higher degree of similarity to PHHs when compared to conventional 2D systems. These results suggest that 3D cellulosic scaffolds are ideal for the long-term cultures needed to mature hPSC-HLCs. The mature hPSC-HLCs with improved cellular function can be continually maintained in the scaffolds and directly used for hepatotoxicity assays, making this system highly attractive for drug testing applications.

Cytochrome P450 induction response in tethered spheroids as a three-dimensional human hepatocyte in vitro model.

Cytochrome P450 (CYP) induction is a key risk factor of clinical drug-drug interactions that has to be mitigated in the early phases of drug discovery. Three-dimensional (3D) cultures of hepatocytes in vitro have recently emerged as a potentially better platform to recapitulate the in vivo liver structure and to maintain long-term hepatic functions as compared with conventional two-dimensional (2D) monolayer cultures. However, the majority of published studies on 3D hepatocyte models use rat hepatocytes and the response to CYP inducers between rodents and humans is distinct. In the present study, we constructed tethered spheroids on RGD/galactose-conjugated membranes as an in vitro 3D model using cryopreserved human hepatocytes. CYP3A4 mRNA expression in the tethered spheroids was induced to a significantly greater extent than those in the collagen sandwich cultures, indicating the transcriptional regulation was more sensitive to the CYP inducers in the 3D model. Induction of CYP1A2, CYP2B6 and CYP3A4 activities in the tethered spheroids were comparable to, if not higher than that observed in the collagen sandwich cultures. The membrane-based model is readily integrated into multi-well plates for higher-throughput drug testing applications, which might be an alternative model to screen the CYP induction potential in vitro with more physiological relevance.

Substrate Stiffness Modulates the Maturation of Human Pluripotent Stem-Cell-Derived Hepatocytes.

Obtaining functional hepatocytes from human pluripotent stem cells (hPSCs) holds great potential for applications in drug safety testing, as well in the field of regenerative medicine. However, developing functionally mature hPSC-derived hepatocytes (hPSC-Heps) remains a challenge. We hypothesized that the cellular microenvironment plays a vital role in the maturation of immature hepatocytes. In this study, we examined the role of mechanical stiffness, a key component of the cellular microenvironment, in the maturation of hPSC-Heps. We cultured hPSC-Heps on collagen-coated polyacrylamide hydrogels with varying elastic moduli. On softer substrates the hPSC-Heps formed compact colonies while on stiffer substrates they formed a diffuse monolayer. We observed an inverse correlation between albumin production and substrate stiffness. The expression of key cytochrome enzymes, which are expressed at higher levels in the adult liver compared to the fetal liver, also correlated inversely with substrate stiffness, whereas fetal markers such as Cyp3A7 and AFP showed no correlation with stiffness. Culture of hPSC-Heps on soft substrates for 12 days led to 10-30 fold increases in the expression of drug-metabolizing enzymes. These results demonstrate that substrate stiffness similar to that of the liver enables aspects of the maturation of hPSC-Heps.

MicroRNA sequencing and molecular mechanisms analysis of the effects of gold nanoparticles on human dermal fibroblasts.

The aim of this study is to investigate the mechanism of the effects of gold nanoparticles (GNPs) on human dermal fibroblasts (HDFs) at the microRNA level. First, 20-nm GNPs were synthesized and their effect on HDF proliferation was assayed. SOLiD sequencing technology was then utilized to obtain the microRNA expression profile after GNP treatment. The microRNA expression data were compared with previously obtained mRNA and protein expression data to identify the microRNA target mRNAs/proteins. Moreover, bioinformatics analyses and validation experiments were conducted. Lastly, the roles of GNPs and silver nanoparticle (SNPs) on HDFs were compared at the microRNA level. The results showed that GNPs were not cytotoxic as 202 microRNAs were differentially expressed after treatment with 200 µm GNPs for 1, 4 and 8 h. Bioinformatics analyses revealed that these dysregulated miRNAs mainly functioned in metabolic processes and participated in 71 biological pathways, including two key pathways in which the differentially expressed miRNA, target mRNAs and proteins were simultaneously joined, the mRNA processing pathway and MAPK signaling pathway. Biological experiments in cells confirmed that GNPs affected energy metabolism but did not induce apoptosis, destroy the cytoskeleton or induce reactive oxygen species (ROS) production. Comparing the mechanism of the effects of GNPs and SNPs on HDFs at the microRNA level, it was found that, unlike SNPs, GNPs impacted the cell cycle, weakened the ATP synthesis inhibition and cytoskeleton damage, suppressed apoptosis, and did not lead to cytotoxicity. The difference in ROS production by these two nanoparticles might partially explain the fact that GNPs showed no cytotoxic effects on HDFs, unlike SNPs.

Proteomic analysis of molecular biocompatibility of gold nanoparticles to human dermal fibroblasts-fetal.

The aim of the present study is to investigate the molecular effects of Gold nanoparticles (GNPs) on the human dermal fibroblasts-fetal (HDF-f) at the level of protein expression. 20-nm GNPs were prepared using chemical reduction method. After HDF-f were treated with 200 microM GNPs for 1, 4 and 8 h, protein expression profiles were obtained using two-dimensional difference gel electrophoresis (2D-DIGE) and mass spectra (MS) analysis. The obtained differential expressed proteins were analyzed by clustering, gene microarray pathway profiler (GenMAPP) and Ingenuity pathway analysis (IPA) analysis, and verified by western blot. 40 protein spots were filtered with different expression in abundance in all three-culture periods and 24 unique proteins were identified. Bioinformatics analysis results indicated that GNPs might have an influence on the HDF-f in the aspects of signal transduction, actin cytoskeleton, energy metabolism, oxidative stress cell transcription factor, etc. Compared with the gene expression effects induced by GNPs in our previous research, certain relationships at molecular level after HDF-f treated with GNPs were identified. The proteomic analysis used here would also be a useful tool to improve the mechanistic understanding of nanomaterials biocompatibility.

Tethered spheroids as an in vitro hepatocyte model for drug safety screening.

Hepatocyte spheroids mimic many in vivo liver-tissue phenotypes but increase in size during extended culture which limits their application in drug testing applications. We have developed an improved hepatocyte 3D spheroid model, namely tethered spheroids, on RGD and galactose-conjugated membranes using an optimized hybrid ratio of the two bioactive ligands. Cells in the spheroid configuration maintained 3D morphology and uncompromised differentiated hepatocyte functions (urea and albumin production), while the spheroid bottom was firmly tethered to the substratum maintaining the spheroid size in multi-well plates. The oblate shape of the tethered spheroids, with an average height of 32 µm, ensured efficient nutrient, oxygen and drug access to all the cells within the spheroid structure. Cytochrome P450 induction by prototypical inducers was demonstrated in the tethered spheroids and was comparable or better than that observed with hepatocyte sandwich cultures. These data suggested that tethered 3D hepatocyte spheroids may be an excellent alternative to 2D hepatocyte culture models for drug safety applications.

Global gene expression analysis of the effects of gold nanoparticles on human dermal fibroblasts.

In order to investigate the molecular effects of gold nanoparticles (GNPs) and cell interaction, after human dermal fibroblasts-fetal (HDF-f) treated with GNPs for 1, 4 and 8 h, the cytotoxicity was evaluated with methylthiazoltetrazolium (MTT) assay. Flow cytometry experiment was used to assess effects of GNPs on cell cycle and apoptosis. Differentially expressed genes in HDF-f treated with GNPs were obtained using gene expression profile microarray. The gene differential expression profile was analyzed by clustering, Gene Ontology (GO) and biological pathway. The results from these analyses were integrated to comprehensively interpret the data gained from microarray. It suggests that the exposure of HDF-f to GNPs might lead to the disturbance of cell cycle regulation, cellular oxidative stress and affect regulation of actin cytoskeleton, and other cellular activities such as cell adhesion, energy metabolism and signal transduction may be also affected. Compared with the cytotoxicological mechanisms induced by Ni2+ from our previous research and by GNPs from the present study, different underlying biological processes and gene regulations were found. The integration of microarray and bioinformatics analysis can provide a specific and efficient routine to discuss molecular effects of cellular response to biomaterials.

Aqueous synthesis of gold nanoparticles and their cytotoxicity in human dermal fibroblasts-fetal.

The unique physicochemical properties of nanoparticles make them promising substrates for application in the medical area. As there are no safety regulations yet, concerns about future health problems are rising. This study was conducted to prepare approximately 20 nm gold nanoparticles (GNPs) by a chemical reduction method and evaluate their cytotoxicity by MTT assay using human dermal fibroblasts-fetal (HDF-f). 10-50 nm GNPs could be obtained in redistilled water by varying the amount of sodium citrate. MTT results showed that approximately 20 nm GNPs did not cause cell death at a maximum concentration of 300 microM but affected the morphology of HDF-f when their concentration increased.

Mechanisms of cytotoxicity of nickel ions based on gene expression profiles.

This study investigated cytotoxic effects of Ni(II) to mouse fibroblast cells (L-929) on the level of gene expression profiles with cDNA microarray. The gene expression profiles of L-929 were detected after the cells were cultured in the medium with 200 microm Ni(II) for 24, 48 and 72 h, respectively, and the cytotoxicity of Ni(II) was evaluated with methylthiazoltetrazolium (MTT) assay. 20 up-regulated genes and 19 down-regulated genes were differentially expressed in all three-culture periods. Gene ontology analysis showed that the L-929 cells which responded to Ni(II) covered a broad range of functional gene groups including cellular biological process, molecular function, and cellular component. Ni(II) has extensive effects on cells by inhibiting cell proliferation and differentiation through inducing cell apoptosis, affecting cell development and influencing cholesterol metabolism.

Efficient gene delivery targeted to the brain using a transferrin-conjugated polyethyleneglycol-modified polyamidoamine dendrimer.

The blood-brain barrier (BBB) poses great difficulties for gene delivery to the brain. To circumvent the BBB, we investigated a novel brain-targeting gene vector based on the nanoscopic high-branching dendrimer, polyamidoamine (PAMAM), in vitro and in vivo. Transferrin (Tf) was selected as a brain-targeting ligand conjugated to PAMAM via bifunctional polyethyleneglycol (PEG), yielding PAMAM-PEG-Tf. UV and nuclear magnetic resonance (NMR) spectroscopy were used to evaluate the synthesis of vectors. The characteristics and biodistribution of gene vectors were evaluated by fluorescent microscopy, flow cytometry, and a radiolabeling method. The transfection efficiency of vector/DNA complexes in brain capillary endothelial cells (BCECs) was evaluated by fluorescent microscopy and determination of luciferase activity. The potency of vector/DNA complexes was evaluated by using frozen sections and measuring tissue luciferase activity in Balb/c mice after i.v. administration. UV and NMR results demonstrated the successful synthesis of PAMAM-PEG-Tf. This vector showed a concentration-dependent manner in cellular uptake study and a 2.25-fold brain uptake compared with PAMAM and PAMAM-PEG in vivo. Transfection efficiency of PAMAM-PEG-Tf/DNA complex was much higher than PAMAM/DNA and PAMAM-PEG/DNA complexes in BCECs. Results of tissue expression experiments indicated the widespread expression of an exogenous gene in mouse brain after i.v. administration. With a PAMAM/DNA weight ratio of 10:1, the brain gene expression of the PAMAM-PEG-Tf/DNA complex was approximately 2-fold higher than that of the PAMAM/DNA and PAMAM-PEG/DNA complexes. These results suggested that PAMAM-PEG-Tf can be exploited as a potential nonviral gene vector targeting to brain via noninvasive administration.

Characterization of lactoferrin receptor in brain endothelial capillary cells and mouse brain.

We present, herein, the evidence for lactoferrin (Lf) binding sites in brain endothelial capillary cells (BCECs) and mouse brain. The results from confocal microscopy showed the presence of Lf receptors on the surface of BCECs and the receptor-mediated endocytosis for Lf to enter the cells. Saturation binding analyses revealed that Lf receptors exhibited two classes of binding sites in BCECs (high affinity: dissociation constant (K (d)) = 6.77 nM, binding site density (B (max)) = 10.3 fmol bound/mug protein; low affinity: K (d) = 4815 nM, B (max) = 1190 fmol bound/mug protein) and membrane preparations of mouse brain (high affinity: K (d) = 10.61 nM, B (max) = 410 fmol bound/mug protein; low affinity: K (d) = 2228 nM, B (max) = 51641 fmol bound/mug protein). The distribution study indicated the effective uptake of (125)I-Lf in brain after intravenous administration. The present study provides experimental evidence for the application of Lf as a novel ligand for brain targeting.