3D Spheroids Facilitate Differentiation of Human Adipose-Derived Mesenchymal Stem Cells into Hepatocyte-Like Cells via p300-Mediated H3K56 Acetylation

Hepatocyte-like cells (HLCs) that are differentiated from mesenchymal stem cells (MSCs) provide a valuable resource for drug screening and cell-based regeneration therapy. Differentiating HLCs into 3D spheroids enhances their phenotypes and functions. However, the molecular mechanisms underlying MSCs hepatogenic differentiation are not fully understood. In this study, we generated HLCs from human adipose-derived mesenchymal stem cells (hADMSCs) in both 2D and 3D cultures. We performed an acetyl-proteomics assay on the HLCs derived from both 2D and 3D differentiation and identified a differential change in H3K56 acetylation between the 2 differentiated cells. Our findings revealed that 3D differentiation activated ALB gene transcription by increasing the acetylation level of H3K56, thereby enhancing the phenotypes and functions of HLCs and further promoting their maturation. Notably, inhibiting p300 reduced the acetylation level of H3K56 during hepatogenic differentiation, leading to decreased phenotypes and functions of HLCs, whereas activation of p300 promoted hepatogenic differentiation, suggesting that p300 plays a critical role in this process. In summary, our study demonstrates a potential mechanism through which 3D spheroids differentiation facilitates hADMSCs differentiation into HLCs by promoting p300-mediated H3K56 acetylation, which could have significant clinical applications in liver regeneration and disease modeling.

Compact automated culture machine for human induced pluripotent stem cell maintenance and differentiation

The technologies used to generate human induced pluripotent stem cell (iPSC) from somatic cells potentially enable the wide application of iPSC-derived differentiated cells in industrial research fields as a replacement for animals. However, as highly trained individuals are required to obtain reproducible results, this approach has limited social implementation. In the research field of iPSC, it is believed that documentable information is not enough for reproducing the quality of the differentiated cells. Therefore, automated culture machines for cell processing should make the starting of iPSC-using researches easier. We developed a programmable all-in-one automated culture machine, with dense and compact constitution that fits within a normal biosafety cabinet (200 mm wide, 233 mm height, and 110 mm depth). This instrument was fabricated using novel x-y-z-axes-rail-system, such as an overhead traveling crane, in a factory, which served as the main handling machinery. This machine enabled stable and efficient expansion of human iPSC under the feeder-free condition, without karyotype alterations, and simultaneously differentiated the cells into various cell types, including cardiomyocytes, hepatocytes, neural progenitors, and keratinocytes. Overall, this machine would facilitate the social implementation of human pluripotent stem cells and contribute to the accumulation of sharable knowledge for the standardization of the entire handling processes of iPSC in pharmaceutical, food, and cosmetic research.

Induction of Hepatic Regeneration in an Experimental Model Using Hepatocyte-Differentiated Mesenchymal Stem Cells

Mesenchymal stem cell (MSC)-based liver tissue engineering on nanofibrous scaffold holds great promise for cell-based therapy in liver injuries and end-stage liver failure treatments. MSCs were generated from umbilical cord blood. Hepatogenic differentiation was induced on two-dimensional (2D) and three-dimensional (3D) culture system and characterized by morphology, scanning electron microscopy, immunocytochemistry, and gene expression. Albumin and α-1 antitrypsin (AAT) in culture supernatants were measured. Differentiated cells were administered intravenous into a murine model of carbon tetra induced liver cirrhosis. After 12 weeks of injection, liver pathology was examined. The hepatogenic differentiated MSCs stained positively for albumin, alpha fetoprotein, HepPar1, cytokeratin 7 and 18, and OV6 with more mature cells, hexagonal in shape with central nuclei forming large sheets in groups in 3D culture system. AAT secretion and indocyanine green uptake were significantly increased in 3D system. In experimental model, MSC-3D treated group exhibited maximal restoration of liver architecture with absent septal fibrosis and marked improvement of alanine transaminase (ALT) and aspartate transaminase (AST), and mild increase in albumin. Both 3D and 2D culture system are effective in functional hepatogenic differentiation from MSCs and serve as a vehicle in liver tissue engineering. In vivo hepatogenic differentiation is more effective on 3D scaffold, with better functional recovery.

Isolation of Induced Pluripotent Cells from Stromal Liver Cells of Patients with Alcoholic Cirrhosis

Stromal liver cells obtained from liver biopsy specimens of a patient with alcoholic cirrhosis can proliferate for a long time in culture passing more than 30 passages. In the course of culturing from early to late passages, acceleration of cell proliferation, decrease of the expression of some markers, and loss of hepatogenic differentiation potential were observed. On passage 30, induced pluripotent stem cells were obtained from these cells and comparative analysis of adipogenic and hepatic differentiation potencies of these cells and original liver stromal cells was performed. Induced pluripotent stem cells differentiated into both directions more efficiently and more rapidly than initial cells. Under conditions of hepatic differentiation, liver stromal cells started to express markers of definitive endoderm, but not markers of immature/mature hepatocytes, whereas induced pluripotent stem cells consistently expressed markers of definitive endoderm, immature/mature hepatocytes.

Injectable Polypeptide Thermogel as a Tissue Engineering System for Hepatogenic Differentiation of Tonsil-Derived Mesenchymal Stem Cells

A poly(ethylene glycol)-b-poly(l-alanine) (PEG-l-PA) hydrogel incorporating tonsil-derived mesenchymal stem cells (TMSCs), tauroursodeoxycholic acid (TUDCA), hepatocyte growth factor (HGF), and fibroblast growth factor 4 (FGF4) was prepared through thermal gelation of an aqueous polymer solution for an injectable tissue engineering application. The thermal gelation accompanied conformational changes of both PA and PEG blocks. The gel modulus at 37 °C was controlled to be 1000 Pa by using a 14.0 wt % aqueous polymer solution. The gel preserved its physical integrity during the 3D culture of the cells. TUDCA, HGF, and FGF4 were released from the PEG-l-PA hydrogel over 21 days of the 3D cell culture period. TMSCs initially exhibited a spherical shape, whereas some fibers protruded from the cells on days 14-21 of 3D culture. The injectable system exhibited pronounced expressions of the hepatic biomarkers at both mRNA and protein levels, which are significantly better than the commercially available hyaluronic acid gel. In particular, the hepatogenically differentiated cells from the TMSCs in the injectable system demonstrated hepatic biofunctions comparable to HepG2 cells for the uptakes of low density lipoproteins (52%) and indocyanine green (76%), and the production of albumin (40%) and urea (52%), which are also significantly better than the 3D-cultured cells in the commercially available hyaluronic acid gel. Our studies suggest that the PEG-l-PA thermogel incorporating TMSCs, TUDCA, and growth factors is highly promising as an in situ forming tissue engineering system.

Up regulation of liver-enriched transcription factors HNF4a and HNF6 and liver-specific microRNA (miR-122) by inhibition of let-7b in mesenchymal stem cells

MicroRNAs are small non-coding RNAs that regulate key processes of the stem cells. Although, microRNAs have emerged as powerful regulators of differentiation, few studies have been focused on the post-transcriptional regulation of hepatic differentiation in mesenchymal stem cells (MSCs) by microRNAs. The aim of this study was to evaluate the specific effect of let-7 microRNAs in particular let-7b in hepatic commitment of human adipose tissue-derived mesenchymal stem cells (hAT-MSCs). The dynamic expression profile of let-7a, b, c microRNAs and two liver-enriched transcription factors (LETFs) HNF4a and HNF6 was studied during in vitro hepatic differentiation of hAT-MSCs. Let-7b was used for transient overexpression and knockdown investigations. It was shown that the expression of LETFs is inversely correlated with those of let-7 miRNAs during differentiation progress (p < 0.05). Inhibition of let-7b caused upregulation of LETFs, an increase in the expression of miR-122 (p < 0.01) emulating the features of functional hepatocytes, and accumulation of hAT-MSCs in the G0 /G1 phase of cell cycle, triggering initiation of hepatic commitment. In conclusion, transient inhibition of let-7b activates hepatic differentiation of hAT-MSCs. The findings of this work might help optimization of in vitro hepatogenic differentiation utilizing microRNAs and hAT-MSCs that could be used for therapeutic purposes.