Methichit Wattanapanitch

Dual Small-Molecule Targeting of SMAD Signaling Stimulates Human Induced Pluripotent Stem Cells toward Neural Lineages

Incurable neurological disorders such as Parkinson’s disease (PD), Huntington’s disease (HD), and Alzheimer’s disease (AD) are very common and can be life-threatening because of their progressive disease symptoms with limited treatment options. To provide an alternative renewable cell source for cell-based transplantation and as study models for neurological diseases, we generated induced pluripotent stem cells (iPSCs) from human dermal fibroblasts (HDFs) and then differentiated them into neural progenitor cells (NPCs) and mature neurons by dual SMAD signaling inhibitors. Reprogramming efficiency was improved by supplementing the histone deacethylase inhibitor, valproic acid (VPA), and inhibitor of p160-Rho associated coiled-coil kinase (ROCK), Y-27632, after retroviral transduction. We obtained a number of iPS colonies that shared similar characteristics with human embryonic stem cells in terms of their morphology, cell surface antigens, pluripotency-associated gene and protein expressions as well as their in vitro and in vivo differentiation potentials. After treatment with Noggin and SB431542, inhibitors of the SMAD signaling pathway, HDF-iPSCs demonstrated rapid and efficient differentiation into neural lineages. Six days after neural induction, neuroepithelial cells (NEPCs) were observed in the adherent monolayer culture, which had the ability to differentiate further into NPCs and neurons, as characterized by their morphology and the expression of neuron-specific transcripts and proteins. We propose that our study may be applied to generate neurological disease patient-specific iPSCs allowing better understanding of disease pathogenesis and drug sensitivity assays.

Effects of mesenchymal stem cell-derived cytokines on the functional properties of endothelial progenitor cells.

Human mesenchymal stem cell (hMSC) is a potential source for cell therapy due to its property to promote tissue repair. Although, it has been known that hMSCs promote tissue repair via angiogenic cytokines, the interaction between hMSC-derived cytokines and the endothelial progenitor cells (EPCs), which play an important role in tissue neovascularization, is poorly characterized. We investigate the effect of cytokine released from different sources of hMSCs including bone marrow and gestational tissues on the EPC functions in vitro. The migration, extracellular matrix invasion and vessel formation of EPCs were studied in the presence or absence of cytokines released from various sources of hMSCs using transwell culture system. The migration of EPCs was highest when co-culture with secretory factors from placenta-derived hMSCs (PL-hMSCs) compared to those co-culture with other sources of hMSCs. For invasion and vessel formation, secretory factors from bone marrow-derived hMSCs (BM-hMSCs) could produce the maximal enhancement compared to other sources. We further identified the secreted cytokines and found that the migratory-enhancing cytokine from PL-hMSCs was PDGF-BB while the enhancing cytokine from BM-hMSCs on invasion was IGF-1. For vessel formation, the cytokines released from BM-hMSCs were IGF1 and SDF-1. In conclusion, hMSCs can release angiogenic cytokines which increase the migration, invasion and vessel forming capacity of EPCs. We can then use hMSCs as a source of angiogenic cytokines to induce neovascularization in injured/ischemic tissues.

Bortezomib enhances the osteogenic differentiation capacity of human mesenchymal stromal cells derived from bone marrow and placental tissues.

Bortezomib (BZB) is a chemotherapeutic agent approved for treating multiple myeloma (MM) patients. In addition, there are several reports showing that bortezomib can induce murine mesenchymal stem cells (MSCs) to undergo osteogenic differentiation and increase bone formation in vivo. MSCs are the multipotent stem cells that have capacity to differentiate into several mesodermal derivatives including osteoblasts. Nowadays, MSCs mostly bone marrow derived have been considered as a valuable source of cell for tissue replacement therapy. In this study, the effect of bortezomib on the osteogenic differentiation of human MSCs derived from both bone marrow (BM-MSCs) and postnatal sources such as placenta (PL-MSCs) were investigated. The degree of osteogenic differentiation of BM-MSCs and PL-MSCs after bortezomib treatment was assessed by alkaline phosphatase (ALP) activity, matrix mineralization by Alizarin Red S staining and the expression profiles of osteogenic differentiation marker genes, Osterix, RUNX2 and BSP. The results showed that 1 nM and 2 nM BZB can induce osteogenic differentiation of BM-MSCs and PL-MSCs as demonstrated by increased ALP activity, increased matrix mineralization and up-regulation of osteogenic differentiation marker genes, Osterix, RUNX2 and BSP as compared to controls. The enhancement of osteogenic differentiation of MSCs by bortezomib may lead to the potential therapeutic applications in human diseases especially patients with osteopenia.

Cell type of origin influences iPSC generation and differentiation to cells of the hematoendothelial lineage

The use of induced pluripotent stem cells (iPSCs) as a source of cells for cell-based therapy in regenerative medicine is hampered by the limited efficiency and safety of the reprogramming procedure and the low efficiency of iPSC differentiation to specialized cell types. Evidence suggests that iPSCs retain an epigenetic memory of their parental cells with a possible influence on their differentiation capacity in vitro. We reprogramme three cell types, namely human umbilical cord vein endothelial cells (HUVECs), endothelial progenitor cells (EPCs) and human dermal fibroblasts (HDFs), to iPSCs and compare their hematoendothelial differentiation capacity. HUVECs and EPCs were at least two-fold more efficient in iPSC reprogramming than HDFs. Both HUVEC- and EPC-derived iPSCs exhibited high potentiality toward endothelial cell differentiation compared with HDF-derived iPSCs. However, only HUVEC-derived iPSCs showed efficient differentiation to hematopoietic stem/progenitor cells. Examination of DNA methylation at promoters of hematopoietic and endothelial genes revealed evidence for the existence of epigenetic memory at the endothelial genes but not the hematopoietic genes in iPSCs derived from HUVECs and EPCs indicating that epigenetic memory involves an endothelial differentiation bias. Our findings suggest that endothelial cells and EPCs are better sources for iPSC derivation regarding their reprogramming efficiency and that the somatic cell type used for iPSC generation toward specific cell lineage differentiation is of importance.

Transdifferentiation of erythroblasts to megakaryocytes using FLI1 and ERG transcription factors

Platelet transfusion has been widely used to prevent and treat life-threatening thrombocytopenia; however, preparation of a unit of concentrated platelet for transfusion requires at least 4-6 units of whole blood. At present, a platelet unit from a single donor can be prepared using apheresis, but lack of donors is still a major problem. Several approaches to produce platelets from other sources, such as haematopoietic stem cells and pluripotent stem cells, have been attempted but the system is extremely complicated, time-consuming and expensive. We now report a novel and simpler technology to obtain platelets using transdifferentiation of human bone marrow erythroblasts to megakaryocytes with overexpression of the FLI1 and ERG genes. The obtained transdifferentiated erythroblasts (both from CD71+ and GPA+ erythroblast subpopulations) exhibit typical features of megakaryocytes including morphology, expression of specific genes (cMPL and TUBB1) and a marker protein (CD41). They also have the ability to generate megakaryocytic CFU in culture and produce functional platelets, which aggregate with normal human platelets to form a normal-looking clot. Overexpression of FLI1 and ERG genes is sufficient to transdifferentiate erythroblasts to megakaryocytes that can produce functional platelets.

Induced pluripotent stem cell line MUSIi006-A derived from hair follicle keratinocytes as a non-invasive somatic cell source

In this study, we used hair follicle keratinocytes for reprogramming. Collection of plucked hairs offers advantages over other somatic cells because no medical professional or operation room is required. Keratinocytes were isolated from plucked hairs of a 21-year-old healthy woman and characterized for the expression of cytokeratin 14 (CK14). Reprogramming of keratinocytes was performed using Sendai virus. Further characterization of the keratinocyte-derived iPSC line (designated as MUSIi006-A) confirmed that the cell line was pluripotent, free from Sendai viral genome and transgenes, and retained normal karyotype. Our method represents an easy, non-invasive and efficient approach for iPSC generation from hair samples.

One-step genetic correction of hemoglobin E/beta-thalassemia patient-derived iPSCs by the CRISPR/Cas9 system

BackgroundThalassemia is the most common genetic disease worldwide; those with severe disease require lifelong blood transfusion and iron chelation therapy. The definitive cure for thalassemia is allogeneic hematopoietic stem cell transplantation, which is limited due to lack of HLA-matched donors and the risk of post-transplant complications. Induced pluripotent stem cell (iPSC) technology offers prospects for autologous cell-based therapy which could avoid the immunological problems. We now report genetic correction of the beta hemoglobin (HBB) gene in iPSCs derived from a patient with a double heterozygote for hemoglobin E and β-thalassemia (HbE/β-thalassemia), the most common thalassemia syndrome in Thailand and Southeast Asia.MethodsWe used the CRISPR/Cas9 system to target the hemoglobin E mutation from one allele of the HBB gene by homology-directed repair with a single-stranded DNA oligonucleotide template. DNA sequences of the corrected iPSCs were validated by Sanger sequencing. The corrected clones were differentiated into hematopoietic progenitor and erythroid cells to confirm their multilineage differentiation potential and hemoglobin expression.ResultsThe hemoglobin E mutation of HbE/β-thalassemia iPSCs was seamlessly corrected by the CRISPR/Cas9 system. The corrected clones were differentiated into hematopoietic progenitor cells under feeder-free and OP9 coculture systems. These progenitor cells were further expanded in erythroid liquid culture system and developed into erythroid cells that expressed mature HBB gene and HBB protein.ConclusionsOur study provides a strategy to correct hemoglobin E mutation in one step and these corrected iPSCs can be differentiated into hematopoietic stem cells to be used for autologous transplantation in patients with HbE/β-thalassemia in the future.

Establishment of an integration-free induced pluripotent stem cell line (MUSIi005-A) from exfoliated renal epithelial cells

Human induced pluripotent stem cells (iPSCs) were generated from exfoliated renal epithelial cells isolated from a urine sample of a 31-year-old healthy woman. Epithelial cells were characterized for the expression of E-cadherin and reprogrammed using non-integrating Sendai viral vectors. The urine-derived iPSC line (designated as MUSIi005-A) was karyotypically normal, expressed pluripotent markers, differentiated into cells of three embryonic germ layers, and showed no viral and transgene expressions at passage 29. Our protocol offers a non-invasive and efficient approach for iPSC generation from patients with genetic or acquired disorders.

Establishment of a human iPSC line (MUSIi007-A) from peripheral blood of normal individual using Sendai viral vectors

Human induced pluripotent stem cell (iPSC) line was generated from peripheral blood mononuclear cells (PBMNCs) isolated from a 26-year-old healthy subject to use as a control group for the iPSC line carrying compound heterozygote for mutation in KLF1 gene. The cells were reprogrammed using integration-free method, Sendai viral (SeV) vectors containing KOS, hc-MYC and hKLF4. The established iPSC line (MUSIi007-A) exhibited a normal karyotype, expressed pluripotent markers and displayed in vitro and in vivo differentiation potential into cells of three embryonic germ layers. Resource table.

Derivation of an induced pluripotent stem cell line (MUSIi004-A) from dermal fibroblasts of a 48-year-old spinocerebellar ataxia type 3 patient

Dermal fibroblasts were obtained from a 48-year-old female patient with spinocerebellar ataxia type 3 (SCA3). Fibroblasts were reprogrammed by nucleofection with episomal plasmids, carrying L-MYC, LIN28, OCT4, SOX2, KLF4, EBNA-1 and shRNA against p53. The SCA3 patient-specific iPSC line, MUSIi004-A, was characterized by immunofluorescence staining to verify the expression of pluripotent markers. The iPSC line exhibited an ability to differentiate into three germ layers by embryoid body (EB) formation. Karyotypic analysis of the MUSIi004-A line was normal. The mutant allele was still present in the iPSC line. This iPSC line represents a useful tool for studying neurodegeneration in SCA3.