Generation of skin-derived iPSCs from an Osteogenesis imperfecta patient carrying WNT1c.677C>T mutation / 中华医学遗传学杂志

OBJECTIVE@#To obtain skin-derived induced pluripotent stem cells (iPSCs) from an Osteogenesis imperfecta (OI) patient carrying WNT1c.677C>T mutation in order to provide a new cell model for investigating the underlying molecular mechanism and stem cell therapy for OI.@*METHODS@#The pathogenic variant of the patient was identified by Sanger sequencing. With informed consent from the patient, skin tissue was biopsied, and primary skin fibroblasts were cultured. Skin fibroblasts were induced into iPSCs using Sendai virus-mediated non-genomic integration reprogramming method. The iPSC cell lines were characterized for pluripotency, differentiation capacity, and karyotyping assay.@*RESULTS@#The patient was found to carry homozygous missense c.677C>T (p.Ser226Leu) mutation of the WNT1 gene. The established iPSC lines possessed self-renewal and capacity for in vitro differentiation. It also has a diploid karyotype (46,XX).@*CONCLUSION@#A patient-specific WNT1 gene mutation (WNT1c.677C>T) iPSC line was established, which can provide a cell model for the study of OI caused by the mutation.

Generating universal chimeric antigen receptor expressing cell products from induced pluripotent stem cells: beyond the autologous CAR-T cells / 中华医学杂志(英文版)

Adoptive therapeutic immune cells, such as chimeric antigen receptor (CAR)-T cells and natural killer cells, have established a new generation of precision medicine based on which dramatic breakthroughs have been achieved in intractable lymphoma treatments. Currently, well-explored approaches focus on autologous cells due to their low immunogenicity, but they are highly restricted by the high costs, time consumption of processing, and the insufficiency of primary cells in some patients. Induced pluripotent stem cells (iPSCs) are cell sources that can theoretically produce indefinite well-differentiated immune cells. Based on the above facts, it may be reasonable to combine the iPSC technology and the CAR design to produce a series of highly controllable and economical "live" drugs. Manufacturing hypoimmunogenic iPSCs by inactivation or over-expression at the genetic level and then arming the derived cells with CAR have emerged as a form of "off-the-shelf" strategy to eliminate tumor cells efficiently and safely in a broader range of patients. This review describes the reasonability, feasibility, superiority, and drawbacks of such approaches, summarizes the current practices and relevant research progress, and provides insights into the possible new paths for personalized cell-based therapies.

Rapamycin mediated caspase 9 homodimerization to safeguard human pluripotent stem cell therapy / 生物工程学报

Human induced pluripotent stem cells (hiPSCs) are promising in regenerative medicine. However, the pluripotent stem cells (PSCs) may form clumps of cancerous tissue, which is a major safety concern in PSCs therapies. Rapamycin is a safe and widely used immunosuppressive pharmaceutical that acts through heterodimerization of the FKBP12 and FRB fragment. Here, we aimed to insert a rapamycin inducible caspase 9 (riC9) gene in a safe harbor AAVS1 site to safeguard hiPSCs therapy by drug induced homodimerization. The donor vector containing an EF1α promoter, a FRB-FKBP-Caspase 9 (CARD domain) fusion protein and a puromycin resistant gene was constructed and co-transfected with sgRNA/Cas9 vector into hiPSCs. After one to two weeks screening with puromycin, single clones were collected for genotype and phenotype analysis. Finally, rapamycin was used to induce the homodimerization of caspase 9 to activate the apoptosis of the engineered cells. After transfection of hiPSCs followed by puromycin screening, five cell clones were collected. Genome amplification and sequencing showed that the donor DNA has been precisely knocked out at the endogenous AAVS1 site. The engineered hiPSCs showed normal pluripotency and proliferative capacity. Rapamycin induced caspase 9 activation, which led to the apoptosis of all engineered hiPSCs and its differentiated cells with different sensitivity to drugs. In conclusion, we generated a rapamycin-controllable hiPSCs survival by homodimerization of caspase 9 to turn on cell apoptosis. It provides a new strategy to guarantee the safety of the hiPSCs therapy.

Killing effect of anti-MSLN-iCAR-NK cells derived from induced pluripotent stem cells on ovarian epithelial cancer cells / 中华妇产科杂志

Objective: To investigate the cytotoxic effects of induced pluripotent stem (iPS) cells of anti-mesothelin (MSLN)-chimeric antigen receptor natural killer (CAR-NK) cells (anti-MSLN-iCAR-NK cells) on ovarian epithelial cancer cells. Methods: Twenty cases of ovarian cancer patients who underwent surgical treatment at Henan Provincial People's Hospital from September 2020 to September 2021 were collected, and 20 cases of normal ovarian tissues resected during the same period due to other benign diseases were also collected. (1) Immunohistochemistry and immunofluorescence were used to verify the expression of MSLN protein in ovarian cancer tissues. (2) Fresh ovarian cancer tissues were extracted and cultured to obtain primary ovarian cancer cells. Recombinant lentiviral vectors targeting anti-MSLN-CAR-CD244 were constructed and co-cultured with iPS cells to obtain anti-MSLN-iCAR cells. These cells were differentiated into anti-MSLN-iCAR-NK cells using cytokine-induced differentiation method. The cell experiments were divided into three groups: anti-MSLN-iCAR-NK cell group, natural killer (NK) cell group, and control group. (3) Flow cytometry and live cell staining experiment were used to detect the apoptosis of ovarian cancer cells in the three groups. (4) Enzyme-linked immunosorbent assay (ELISA) was used to measure the expression levels of interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), granzyme B (GZMB), perforin 1 (PRF1), interleukin (IL)-6, and IL-10 in the three groups of ovarian cancer cells. Results: (1) Immunohistochemistry analysis showed that a positive expression rate of MSLN protein in ovarian cancer tissues of 65% (13/20), while normal ovarian tissues had a positive rate of 30% (6/20). The comparison between the two groups was statistically significant (χ2=4.912, P=0.027). Immunofluorescence analysis revealed that the positive expression rate of MSLN protein in ovarian cancer tissues was 70% (14/20), while normal ovarian tissues had a positive rate of 30% (6/20). The comparison between the two groups was statistically significant (χ2=6.400, P=0.011). (2) Flow cytometry analysis showed that the apoptotic rate of ovarian cancer cells in the anti-MSLN-iCAR-NK cell group was (29.27±0.85)%, while in the NK cell group and control group were (8.44±0.34)% and (6.83±0.26)% respectively. There were statistically significant differences in the comparisons between the three groups (all P<0.01). Live cell staining experiment showed that the ratio of dead cells to live cells in the anti-MSLN-iCAR-NK cell group was (36.3±8.3)%, while in the NK cell group and control group were (5.4±1.4)% and (2.0±1.3)% respectively. There were statistically significant differences in the comparisons between the three groups (all P<0.001). (3) ELISA analysis revealed that the expression levels of IFN-γ, TNF-α, GZMB, PRF1, IL-6, and IL-10 in ovarian cancer cells of the anti-MSLN-iCAR-NK cell group were significantly higher than those in the NK cell group and the control group (all P<0.05). Conclusion: The anti-MSLN-iCAR-NK cells exhibit a strong killing ability against ovarian cancer cells, indicating their potential as a novel immunotherapy approach for ovarian cancer.

Advances and Applications of Brain Organoids / 神经科学通报·英文版

Understanding the fundamental processes of human brain development and diseases is of great importance for our health. However, existing research models such as non-human primate and mouse models remain limited due to their developmental discrepancies compared with humans. Over the past years, an emerging model, the "brain organoid" integrated from human pluripotent stem cells, has been developed to mimic developmental processes of the human brain and disease-associated phenotypes to some extent, making it possible to better understand the complex structures and functions of the human brain. In this review, we summarize recent advances in brain organoid technologies and their applications in brain development and diseases, including neurodevelopmental, neurodegenerative, psychiatric diseases, and brain tumors. Finally, we also discuss current limitations and the potential of brain organoids.

Directed differentiation of human induced pluripotent stem cells into midbrain / 南方医科大学学报

OBJECTIVE@#To establish an efficient protocol for directed differentiation of human induced pluripotent stem cells (hiPSCs) into functional midbrain dopaminergic progenitor cells (DAPs) in vitro.@*METHODS@#hiPSCs were induced to differentiate into DAPs in two developmental stages. In the first stage (the first 13 days), hiPSCs were induced into intermediate cells morphologically similar to primitive neuroepithelial cells (NECs) in neural induction medium containing a combination of small molecule compounds. In the second stage, the intermediate cells were further induced in neural differentiation medium until day 28 to obtain DAPs. After CM-DiI staining, the induced DAPs were stereotactically transplanted into the right medial forebrain bundle (MFB) of rat models of Parkinson's disease (PD). Eight weeks after transplantation, the motor behaviors of PD rats was evaluated. Immunofluorescence assay of brain sections of the rats was performed at 2 weeks after transplantation to observe the survival, migration and differentiation of the transplanted cells in the host brain microenvironment.@*RESULTS@#hiPSCs passaged stably on Matrigel showed a normal diploid karyotype, expressed the pluripotency markers OCT4, SOX2, and Nanog, and were positive for alkaline phosphatase. The primitive neuroepithelial cells obtained on day 13 formed dense cell colonies in the form of neural rosettes and expressed the neuroepithelial markers (SOX2, Nestin, and PAX6, 91.3%-92.8%). The DAPs on day 28 highly expressed the specific markers (TH, FOXA2, LMX1A and NURR1, 93.3-96.7%). In rat models of PD, the hiPSCs-DAPs survived and differentiated into TH+, FOXA2+ and Tuj1+ neurons at 2 weeks after transplantation. Eight weeks after transplantation, the motor function of PD rats was significantly improved as shown by water maze test (P < 0.0001) and apomorphine-induced rotation test (P < 0.0001) compared with rats receiving vehicle injection.@*CONCLUSION@#HiPSCs can be effectively induced to differentiate into DAPs capable of differentiating into functional neurons both in vivo and in vitro. In rat models of PD, the transplanted hiPSCs-DAPs can survive for more than 8 weeks in the MFB and differentiate into multiple functional neurocytes to ameliorate neurological deficits of the rats, suggesting the potential value of hiPSCs-DAPs transplantation for treatment of neurological diseases.

Generation of male germ cells in vitro from the stem cells / 亚洲男科学杂志(英文版)

Infertility has become a serious disease since it affects 10%-15% of couples worldwide, and male infertility contributes to about 50% of the cases. Notably, a significant decrease occurs in the newborn population by 7.82 million in 2020 compared to 2016 in China. As such, it is essential to explore the effective methods of obtaining functional male gametes for restoring male fertility. Stem cells, including embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs), spermatogonial stem cells (SSCs), and mesenchymal stem cells (MSCs), possess the abilities of both self-renewal and differentiation into germ cells. Significantly, much progress has recently been achieved in the generation of male germ cells in vitro from various kinds of stem cells under the specified conditions, e.g., the coculturing with Sertoli cells, three-dimensional culture system, the addition of growth factors and cytokines, and/or the overexpression of germ cell-related genes. In this review, we address the current advance in the derivation of male germ cells in vitro from stem cells based on the studies of the peers and us, and we highlight the perspectives and potential application of stem cell-derived male gametes in reproductive medicine.

Development of porcine induced pluripotent stem cells with a CD163 reporter system / 生物工程学报

As main recipient cells for porcine reproductive and respiratory syndrome virus (PRRSV), porcine alveolar macrophage (PAM) are involved in the progress of several highly pathogenic virus infections. However, due to the fact that the PAM cells can only be obtained from primary tissues, research on PAM-based virus-host interactions remains challenging. The improvement of induced pluripotent stem cells (iPSCs) technology provides a new strategy to develop IPSCs-derived PAM cells. Since the CD163 is a macrophage-specific marker and a validated receptor essential for PRRSV infection, generation of stable porcine induced pluripotent stem cells lines containing CD163 reporter system play important roles in the investigation of IPSCs-PAM transition and PAM-based virus-host interaction. Based on the CRISPR/Cas9- mediated gene editing system, we designed a sgRNA targeting CD163 locus and constructed the corresponding donor vectors. To test whether this reporter system has the expected function, the reporter system was introduced into primary PAM cells to detect the expression of RFP. To validate the low effect on stem cell pluripotency, we generated porcine iPSC lines containing CD163 reporter and assessed the pluripotency through multiple assays such as alkaline phosphatase staining, immunofluorescent staining, and EdU staining. The red-fluorescent protein (RFP) expression was detected in CD163-edited PAM cells, suggesting that our reporter system indeed has the ability to reflect the expression of gene CD163. Compared with wild-type (WT) iPSCs, the CD163 reporter-iPSCs display similar pluripotency-associated transcription factors expression. Besides, cells with the reporter system showed consistent cell morphology and proliferation ability as compared to WT iPSCs, indicating that the edited-cells have no effect on stem cell pluripotency. In conclusion, we generated porcine iPSCs that contain a CD163 reporter system. Our results demonstrated that this reporter system was functional and safe. This study provides a platform to investigate the iPS-PAM development and virus-host interaction in PAM cells.

The chemical reprogramming of unipotent adult germ cells towards authentic pluripotency and de novo establishment of imprinting

Although somatic cells can be reprogrammed to pluripotent stem cells (PSCs) with pure chemicals, authentic pluripotency of chemically induced pluripotent stem cells (CiPSCs) has never been achieved through tetraploid complementation assay. Spontaneous reprogramming of spermatogonial stem cells (SSCs) was another non-transgenic way to obtain PSCs, but this process lacks mechanistic explanation. Here, we reconstructed the trajectory of mouse SSC reprogramming and developed a five-chemical combination, boosting the reprogramming efficiency by nearly 80- to 100-folds. More importantly, chemical induced germline-derived PSCs (5C-gPSCs), but not gPSCs and chemical induced pluripotent stem cells, had authentic pluripotency, as determined by tetraploid complementation. Mechanistically, SSCs traversed through an inverted pathway of in vivo germ cell development, exhibiting the expression signatures and DNA methylation dynamics from spermatogonia to primordial germ cells and further to epiblasts. Besides, SSC-specific imprinting control regions switched from biallelic methylated states to monoallelic methylated states by imprinting demethylation and then re-methylation on one of the two alleles in 5C-gPSCs, which was apparently distinct with the imprinting reprogramming in vivo as DNA methylation simultaneously occurred on both alleles. Our work sheds light on the unique regulatory network underpinning SSC reprogramming, providing insights to understand generic mechanisms for cell-fate decision and epigenetic-related disorders in regenerative medicine.

iPSCs ameliorate hypoxia-induced autophagy and atrophy in C2C12 myotubes via the AMPK/ULK1 pathway

BACKGROUND: Duchenne muscular dystrophy (DMD) is an X-linked lethal genetic disorder for which there is no effective treatment. Previous studies have shown that stem cell transplantation into mdx mice can promote muscle regeneration and improve muscle function, however, the specific molecular mechanisms remain unclear. DMD suffers varying degrees of hypoxic damage during disease progression. This study aimed to investigate whether induced pluripotent stem cells (iPSCs) have protective effects against hypoxia-induced skeletal muscle injury. RESULTS: In this study, we co-cultured iPSCs with C2C12 myoblasts using a Transwell nested system and placed them in a DG250 anaerobic workstation for oxygen deprivation for 24 h. We found that iPSCs reduced the levels of lactate dehydrogenase and reactive oxygen species and downregulated the mRNA and protein levels of BAX/BCL2 and LC3II/ LC3I in hypoxia-induced C2C12 myoblasts. Meanwhile, iPSCs decreased the mRNA and protein levels of atrogin-1 and MuRF-1 and increased myotube width. Furthermore, iPSCs downregulated the phosphorylation of AMPKA and ULK1 in C2C12 myotubes exposed to hypoxic damage. CONCLUSIONS: Our study showed that iPSCs enhanced the resistance of C2C12 myoblasts to hypoxia and inhibited apoptosis and autophagy in the presence of oxidative stress. Further, iPSCs improved hypoxia-induced autophagy and atrophy of C2C12 myotubes through the AMPK/ULK1 pathway. This study may provide a new theoretical basis for the treatment of muscular dystrophy in stem cells.

Establishment of induced pluripotent stem cell model of Aicardi-Goutières Syndrome mutated in TREX1 / 中华预防医学杂志

To establish and identify induced pluripotent stem cells (iPSCs) derived from patients with Aicardi-Goutières syndrome (AGS) with TREX1 gene 667G>A mutation, and obtain a specific induced pluripotent stem cell model for Aicardi-Goutières syndrome (AGS-iPSCs). A 3-year-old male child with Aicardi-Goutieres syndrome was admitted to Zhongshan People's Hospital in December 2020. After obtaining the informed consent of the patient's family members, 5 ml peripheral blood samples from the patient were collected, and mononuclear cells were isolated. Then,the peripheral blood mononuclear cells(PBMCs) were transduced with OCT3/4, SOX2, c-Myc and Klf4 by using Sendai virus, and PBMCs were reprogrammed into iPSCs. The pluripotency and differentiation ability of the cells were identified by cellular morphological analysis, real-time PCR, alkaline phosphatase staining (AP), immunofluorescence, teratoma formation experiments in mice. The results showed that the induced pluripotent stem cell line of Aicardi-Goutieres syndrome was successfully constructed and showed typical embryonic stem-like morphology after stable passage, RT-PCR showed mRNA expression of stem cell markers, AP staining was positive, OCT4, SOX2, NANOG, SSEA4, TRA-1-81 and TRA-1-60 pluripotency marker proteins were strongly expressed. In vivo teratoma formation experiments showed that iPSCs differentiate into the ectoderm (neural tube like tissue), mesoderm (vascular wall tissue) and endoderm (glandular tissue). Karyotype analysis also confirmed that iPSCs still maintained the original karyotype (46, XY). In conclusion, induced pluripotent stem cell line for Aicardi-Goutières syndrome was successfully established using Sendai virus, which provided an important model platform for studying the pathogenesis of the disease and for drug screening.

hiPSCs and organoids: prediction of arrhythmogenic risks for optimized traditional Chinese medicine / 中国中药杂志

Accurate assessment of the risks associated with traditional Chinese medicine(TCM), such as the potential to induce serious cardiovascular adverse reactions including cardiac arrhythmias, is crucial. This article introduced the pharmacological evaluation strategies for cardiac safety and the progress in cardiac organ research, with a focus on discussing the application prospects of human induced pluripotent stem cells(hiPSCs) and organoids in assessing the risks of TCM-induced cardiac arrhythmias. Compared with traditional animal models, hiPSCs and organoid models provide better reference and predictive capabilities, allowing for more accurate simulation of human cardiac responses. Researchers have successfully generated various cardiac tissue models that mimic the structure and function of the heart to evaluate the effects of TCM on the heart. The hiPSCs model, by reprogramming adult cells into pluripotent stem cells and differentiating them into cardiac cells, enables the generation of personalized cardiac tissue, which better reflects individual differences and drug responses. This provides guidance for the assessment of TCM cardiac toxicity risks. By combining organoid model with cardiac safety pharmacology strategies such as electrocardiogram monitoring and ion channel function assessment, the impact of TCM on the heart can be comprehensively evaluated. In addition, the application of the Comprehensive in Vitro Proarrhythmia Assay(CiPA) approach improves the accuracy of evaluation. Applying the CiPA approach to TCM research reveals potential risks and provides a scientific basis for the clinical application and industrial development of TCM. In conclusion, organoid model and cardiac safety pharmacology evaluation strategies provide important tools for assessing the cardiac toxicity risks of TCM. The combination of hiPSCs model, comprehensive assessment methods, and the CiPA strategy enables an accurate assessment of the risks of TCM-induced cardiac arrhythmias, thus providing a scientific basis for the safe use and international recognition of TCM in clinical practice. This contributes to ensuring the safety and efficacy of TCM and promoting its clinical application and global acceptance.

Organoides: fundamentos, presente y futuro / Organoids: fundamentals, present and future

RESUMEN Los organoides son estructuras miniaturizadas, generadas principalmente a partir de células madre pluripotentes inducidas, que se cultivan en el laboratorio conservando sus características innatas o adquiridas. Tienen el potencial de reproducir procesos de desarrollo biológico, modelar procesos patológicos que permitirán el descubrimiento de nuevos fármacos y propicien la medicina regenerativa. Sin embargo, estas experiencias requieren perfeccionamiento constante porque pueden haberse realizado variaciones en la constitución de estos órganos. Por ello, el presente artículo tiene como objetivo revisar la información actualizada sobre organoides y sus procesos experimentales básicos y recientes, empezando por la gastrulación, para tratar de imitar, en lo posible, la formación de las tres capas: ectodermo, mesodermo y endodermo, incluyendo los factores que intervienen en la inducción, diferenciación y maduración en la generación de estos organoides. Asimismo, el diseño y preparación de medios de cultivo altamente especializados que permitan obtener el órgano seleccionado con la mayor precisión y seguridad. Se realizó una búsqueda de artículos originales y de revisión publicados en PubMed, Nature y Science. Los artículos se seleccionaron por sus resúmenes y por su texto completo. Las conclusiones de este articulo destacan las ventajas futuras en el uso y aplicaciones de los organoides.

ABSTRACT Organoids are tiny structures, mainly generated from induced pluripotent stem cells, which are cultured in the laboratory while retaining their innate or acquired characteristics. They have the potential to reproduce biological development processes, model pathological processes that will enable the discovery of new drugs and promote regenerative medicine. However, these processes require constant improvement because variations may have occurred in the constitution of the organs. Therefore, this article aims to review updated information on organoids and their basic and recent experimental processes, starting with gastrulation, in an attempt to mimic, as much as possible, the formation of the three layers: ectoderm, mesoderm and endoderm; as well as the information regarding the factors involved in the induction, differentiation and maturation during the generation of organoids. Likewise, the design and preparation of highly specialized culture media that allow obtaining the selected organ with the highest precision and safety. We searched for original and review articles published in PubMed, Nature and Science. Articles were selected for their abstracts and full text. The conclusions of this article highlight the future advantages in the use and applications of organoids.

Culture of pluripotent stem cell-derived hepatocytes and organoids / 中华肝脏病杂志

Liver is one of the most important organs in the human body. Liver diseases are also a major threat to human health and longevity. Hepatic decompensation treatment is quite difficult due to multiple reasons. Extracorporeal liver support devices are unable to solve this problem, and there is a severe shortage of orthotopic liver transplant donors. Study of pluripotent stem cell-derived hepatocytes and organoids can determine not only hepatocyte fate, but also liver development, regeneration mechanisms, and pathophysiology. Furthermore, it can be used for drug screening in order to provide a stable source of functional hepatocytes for future transplantation therapy. Culture of pluripotent stem cell-derived hepatocytes and organoids has a self-organizing process similar to liver development, i.e., starting with changes in several key factors, and eventually forming functionally complex cells/organs. This paper introduces the main methods and progress of pluripotent stem cell-derived hepatocytes and organoids, with hope to provide clues for future research.

Hypoxia promotes differentiation of human induced pluripotent stem cells into embryoid bodies in vitro / 南方医科大学学报

OBJECTIVE@#To investigate effects of physiological hypoxic conditions on suspension and adherence of embryoid bodies (EBs) during differentiation of human induced pluripotent stem cells (hiPSCs) and explore the underlying mechanisms.@*METHODS@#EBs in suspension culture were divided into normoxic (21% O2) and hypoxic (5% O2) groups, and those in adherent culture were divided into normoxic, hypoxic and hypoxia + HIF-1α inhibitor (echinomycin) groups. After characterization of the pluripotency with immunofluorescence assay, the hiPSCs were digested and suspended under normoxic and hypoxic conditions for 5 days, and the formation and morphological changes of the EBs were observed microscopically; the expressions of the markers genes of the 3 germ layers in the EBs were detected. The EBs were then inoculated into petri dishes for further culture in normoxic and hypoxic conditions for another 2 days, after which the adhesion and peripheral expansion rate of the adherent EBs were observed; the changes in the expressions of HIF-1α, β-catenin and VEGFA were detected in response to hypoxic culture and echinomycin treatment.@*RESULTS@#The EBs cultured in normoxic and hypoxic conditions were all capable of differentiation into the 3 germ layers. The EBs cultured in hypoxic conditions showed reduced apoptotic debris around them with earlier appearance of cystic EBs and more uniform sizes as compared with those in normoxic culture. Hypoxic culture induced more adherent EBs than normoxic culture (P < 0.05) with also a greater outgrowth rate of the adherent EBs (P < 0.05). The EBs in hypoxic culture showed significantly up-regulated mRNA expressions of β-catenin and VEGFA (P < 0.05) and protein expressions of HIF-1 α, β-catenin and VEGFA (P < 0.05), and their protein expresisons levels were significantly lowered after treatment with echinomycin (P < 0.05).@*CONCLUSION@#Hypoxia can promote the formation and maturation of suspended EBs and enhance their adherence and post-adherent proliferation without affecting their pluripotency for differentiation into all the 3 germ layers. Our results provide preliminary evidence that activation of HIF-1α/β-catenin/VEGFA signaling pathway can enhance the differentiation potential of hiPSCs.

Intermittent compressive force induces cell cycling and reduces apoptosis in embryoid bodies of mouse induced pluripotent stem cells / 国际口腔科学杂志·英文版

In vitro manipulation of induced pluripotent stem cells (iPSCs) by environmental factors is of great interest for three-dimensional (3D) tissue/organ induction. The effects of mechanical force depend on many factors, including force and cell type. However, information on such effects in iPSCs is lacking. The aim of this study was to identify a molecular mechanism in iPSCs responding to intermittent compressive force (ICF) by analyzing the global gene expression profile. Embryoid bodies of mouse iPSCs, attached on a tissue culture plate in 3D form, were subjected to ICF in serum-free culture medium for 24 h. Gene ontology analyses for RNA sequencing data demonstrated that genes differentially regulated by ICF were mainly associated with metabolic processes, membrane and protein binding. Topology-based analysis demonstrated that ICF induced genes in cell cycle categories and downregulated genes associated with metabolic processes. The Kyoto Encyclopedia of Genes and Genomes database revealed differentially regulated genes related to the p53 signaling pathway and cell cycle. qPCR analysis demonstrated significant upregulation of Ccnd1, Cdk6 and Ccng1. Flow cytometry showed that ICF induced cell cycle and proliferation, while reducing the number of apoptotic cells. ICF also upregulated transforming growth factor β1 (Tgfb1) at both mRNA and protein levels, and pretreatment with a TGF-β inhibitor (SB431542) prior to ICF abolished ICF-induced Ccnd1 and Cdk6 expression. Taken together, these findings show that TGF-β signaling in iPSCs enhances proliferation and decreases apoptosis in response to ICF, that could give rise to an efficient protocol to manipulate iPSCs for organoid fabrication.

Generation of hematopoietic stem/progenitor cells with sickle cell mutation from induced pluripotent stem cell in serum-free system

ABSTRACT Introduction Sickle cell disease (SCD) is a monogenic disease and it is estimated that 300,000 infants are born annually with it. Most treatments available are only palliative, whereas the allogeneic hematopoietic stem cell transplantation offers the only potential cure for SCD. Objective Generation of human autologous cells, when coupled with induced pluripotent stem cell (iPSC) technology, is a promising approach for developing study models. In this study, we provide a simple and efficient model for generating hematopoietic cells using iPSCs derived from a sickle cell anemia patient and an inexpensive in-house-prepared medium. Method This study used iPSCs previously generated from peripheral blood mononuclear cells (PBMCs) from a patient with sickle cell anemia (iPSC_scd). Hematopoietic and erythroid differentiation was performed in two steps. Firstly, with the induction of hematopoietic differentiation through embryoid body formation, we evaluated the efficiency of two serum-free media; and secondly, the induction of hematopoietic stem/progenitor cells to erythroid progenitor cells was performed. Results The patient-specific cell line generated CD34+/CD45+ and CD45+/CD43+ hematopoietic stem/progenitor cells and erythroid progenitors, comprising CD36+, CD71+ and CD235a+ populations, as well as the formation of hematopoietic colonies, including erythroid colonies, in culture in a semi-solid medium. Conclusion In conjunction, our results described a simple serum-free platform to differentiate human the iPSCs into hematopoietic progenitor cells. This platform is an emerging application of iPSCs in vitro disease modeling, which can significantly improve the search for new pharmacological drugs for sickle cell disease.

Biocompatibility of extracellular matrix hydrogel with human iPSCs differentiated cardiomyocytes / 中华心血管病杂志

Objective: To observe the biocompatibility of porcine omental derived extracellular matrix (ECM) hydrogel with human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) and the feasibility of ECM hydrogel as a delivery vector of cell transplantation. Methods: A series of chemical, physical and enzymatic methods were applied to acellularize the porcine omentum. Subsequently, the extracted ECM was prepared into thermosensitive hydrogel. The biochemical composition of the hydrogel was identified by histological staining. The microstructure was observed by scanning electron microscopy. The hydrogel was then injected into the myocardium of mice to observe its in situ gelation ability. Differentiation of human induced pluripotent stem cells into cardiomyocytes was achieved by small molecule induction, and then the obtained hiPSC-CMs were cultured. hiPSC-CMs cultured onto the prepared hydrogel were defined as the hydrogel group, while conventionally cultured hiPSC-CMs were defined as the control group. Cardiomyocyte viability and growth patterns were detected using live/dead staining, CCK-8 and phalloidin staining. Immunofluorescence staining and Western blot of cardiomyocytes were used to determine the survival and phenotypic maintenance markers of cardiomyocytes in materials. Results: The results of HE staining, oil red O staining and DAPI fluorescence staining showed that there was no significant cell debris, nucleus and lipid residue in the prepared ECM hydrogel. The Sirius red staining and Alcian blue staining showed that the hydrogel retained collagen and glycolaminoglycan, which were the main components of ECM. The prepared hydrogel behaves as a viscous liquid at 4 ℃ and as a gel state at 37 ℃. Scanning electron microscope results showed that the microstructure of the hydrogel was composed of irregular fibers and pores of different sizes. Under the guidance of ultrasound, the prepared ECM hydrogel could be successfully injected into the myocardium of mice. Immediately after the injection, the hyperechoic signal could be observed under ultrasound, suggesting that the hydrogel remained in the myocardium. HE staining of myocardial tissue evidenced that there was lump of gel in the injection area. The differentiated hiPSC-CMs were co-cultured with the prepared ECM hydrogel, and the results of live/dead staining showed that most of the hiPSC-CMs in the hydrogel group and the control group were alive, dead cells were scanty. The results of CCK-8 test showed that the absorbance values of the two groups were similar (P>0.05). The results of phalloidin staining showed that hiPSC-CMs could extend normally when co-cultured with ECM hydrogel. The cell morphology of the hydrogel group was similar with that of the control group, and there was no statistically significant difference in the F-actin coverage area per cell between the two groups (P>0.05). Immunofluorescence staining of cardiomyocyte markers showed that there was no significant difference in the coverage area of α-actinin and connexin-43 (Cx-43) per field between the hydrogel group and the control group (both P>0.05), the quantitative results of DAPI staining showed that there was no statistically significant difference in the number of cells between the two groups (P>0.05). Meanwhile, the results of Western blot showed that the expression levels of α-actinin and Cx-43 in cardiomyocytes in the hydrogel group were similar as those in the control group (both P>0.05). Conclusions: These results show that preparation of the ECM hydrogel from porcine omentum is successful. The hydrogel has good biocompatibility and no obvious cytotoxicity. Besides, the hydrogel can support the survival of hiPSC-CMs in vitro and maintain its phenotype. These properties make it a promising injectable cardiac tissue engineering material.

Development of a motor neurons-specific fluorescence reporter system / 生物工程学报

Human induced pluripotent stem cells (hiPSCs) have the potential to differentiate into multiple cell types. Motor neurons (MNs) differentiated from hiPSCs are important models of many motor neuron diseases. To simplify the identification of MNs, lentivirus vectors were used to transfer MNs-specific promoter HB9 and red fluorescent protein (RFP) gene into hiPSCs-derived human neural stem cells (hNSCs). Stable positive cells hNSCs-HB9-RFP-Puro were obtained after antibiotic selection. Subsequently, the positive cell line was infected with lentiviruses LV-Ngn2-Sox11-GFP and LV-Isl1-Lhx3-Hygro, which overexpressed the MNs differentiation transcription factor, and differentiated to MNs directly. Differentiated mature MNs showed neuron-like structure, expressed RFP and neuron-related markers β-tubulin and choline acetyltransferase (ChAT) under the control of the MNs-specific promoter HB9. The fluorescence reporter system provides a visual method for directed differentiation and identification of MNs, and may promote the applications of MNs in disease models and drug screening.

Induction and differentiation of induced pluripotent stem cells into macrophages: a review / 生物工程学报

Induced pluripotent stem cells (iPSCs) are a type of cells similar to embryonic stem cells but produced by reprogramed somatic cells. Through in vitro differentiation of iPSCs, we can interrogate the evolution history as well as the various characteristics of macrophages. iPSCs derived macrophages are not only a good model for drug screening, but also an important approach for immunotherapy. This review summarizes the advances, challenges, and future directions in the field of iPSCs-derived macrophages.