Efficient endodermal induction of human adipose stem cells using various concentrations of Activin A for hepatic differentiation

Lineage reprogramming of human adipose mesenchymal stem cells to immune modulatory i-Heps

Pluripotent stem cell derived-hepatocytes depict fetal -hepatocyte characteristics/maturity and are immunogenic limiting their applications. Attempts have been made to derive hepatocytes from mesenchymal stem cells using developmental cocktails, epigenetic modulators and small molecules. However, achieving a stable terminally differentiated functional state had been a challenge. Inefficient hepatic differentiation could be due to lineage restrictions set during development. Hence a novel lineage reprogramming approach has been utilized to confer competence to adipose-mesenchymal stem cells (ADMSCs) to efficiently respond to hepatogenic cues and achieve a stable functional hepatic state. Lineage reprogramming involved co-transduction of ADMSCs with hepatic endoderm pioneer Transcription factor (TF)-FOXA2, HHEX-a homeobox gene and HNF4α-master TF indispensable for hepatic state maintenance. Lineage priming was evidenced by endogenous HFN4α promoter demethylation and robust responsiveness to minimal hepatic maturation cues. Induced hepatocytes (i-Heps) exhibited mesenchymal-to-epithelial transition and terminal hepatic signatures. Functional characterisation of i-Heps for hepatic drug detoxification systems, xenobiotic uptake/clearance, metabolic status and hepatotropic virus entry validated acquisition of stable hepatic state and junctional maturity Exhaustive analysis of MSC memory in i-Heps indicated loss of MSC-immunophenotype and terminal differentiation to osteogenic/adipogenic lineages. Importantly, i-Heps suppressed phytohemagglutinin-induced T-cell blasts, inhibited allogenic mixed-lymphocyte reactions (MLRs) and secreted immunomodulatory- indoleamine 2,3-dioxygenase in T-cell blast co-cultures akin to native ADMSCs. In a nutshell, the present study identifies a novel cocktail of TFs that reprogram ADMSCs to stable hepatic state. i-Heps exhibit adult hepatocyte functional maturity with robust immune-modulatory abilities rendering suitability for rigorous drug testing, hepatocyte-pathogen interaction studies and transplantation in allogenic settings.

Advances in regenerative therapy: A review of the literature and future directions

There is enormous global anticipation for stem cell-based therapies that are safe and effective. Numerous pre-clinical studies present encouraging results on the therapeutic potential of different cell types including tissue derived stem cells. Emerging evidences in different fields of research suggest several cell types are safe, whereas their therapeutic application and effectiveness remain challenged. Multiple factors that influence treatment outcomes are proposed including immunocompatibility and potency, owing to variations in tissue origin, ex-vivo methodologies for preparation and handling of the cells. This communication gives an overview of literature data on the different types of cells that are potentially promising for regenerative therapy. As a case in point, the recent trends in research and development of the mesenchymal stem cells (MSCs) for cell therapy are considered in detail. MSCs can be isolated from a variety of tissues and organs in the human body including bone marrow, adipose, synovium, and perinatal tissues. However, MSC products from the different tissue sources exhibit unique or varied levels of regenerative abilities. The review finally focuses on adipose tissue-derived MSCs (ASCs), with the unique properties such as easier accessibility and abundance, excellent proliferation and differentiation capacities, low immunogenicity, immunomodulatory and many other trophic properties. The suitability and application of the ASCs, and strategies to improve the innate regenerative capacities of stem cells in general are highlighted among others.

Remodeling of Glycosaminoglycans During Differentiation of Adult Human Bone Mesenchymal Stromal Cells Toward Hepatocytes

There is a critical need to generate functional hepatocytes to aid in liver repair and regeneration upon availability of a renewable, and potentially personalized, source of human hepatocytes (hHEP). Currently, the vast majority of primary hHEP are obtained from human tissue through cadavers. Recent advances in stem cell differentiation have opened up the possibility to obtain fully functional hepatocytes from embryonic or induced pluripotent stem cells, or adult stem cells. With respect to the latter, human bone marrow mesenchymal stromal cells (hBMSCs) can serve as a source of autogenetic and allogenic multipotent stem cells for liver repair and regeneration. A major aspect of hBMSC differentiation is the extracellular matrix (ECM) composition and, in particular, the role of glycosaminoglycans (GAGs) in the differentiation process. In this study, we examine the influence of four distinct culture conditions/protocols (T1-T4) on GAG composition and hepatic markers. α-Fetoprotein and hepatocyte nuclear factor-4α were expressed continually over 21 days of differentiation, as indicated by real time quantitative PCR analysis, while albumin (ALB) expression did not begin until day 21. Hepatocyte growth factor (HGF) appears to be more effective than activin A in promoting hepatic-like cells through the mesenchymal-epithelial transition, perhaps due to the former binding to the HGF receptor to form a unique complex that diversifies the biological functions of HGF. Of the four protocols tested, uniform hepatocyte-like morphological changes, ALB secretion, and glycogen storage were found to be highest with protocol T2, which involves both early- and late-stage combinations of growth factors. The total GAG profile of the hBMSC ECM is rich in heparan sulfate (HS) and hyaluronan, both of which fluctuate during differentiation. The GAG profile of primary hHEP showed an HS-rich ECM, and thus, it may be possible to guide hBMSC differentiation to more mature hepatocytes by controlling the GAG profile expressed by differentiating cells.

Microgravity-induced hepatogenic differentiation of rBMSCs on board the SJ-10 satellite

Bone marrow-derived mesenchymal stem cells (BMSCs) are able to differentiate into functional hepatocytelike cells, which are expected to serve as a potential cell source in regenerative medicine, tissue engineering, and clinical treatment of liver injury. Little is known about whether and how space microgravity is able to direct the hepatogenic differentiation of BMSCs in the actual space microenvironment. In this study, we examined the effects of space microgravity on BMSC hepatogenic differentiation on board the SJ-10 Recoverable Scientific Satellite. Rat BMSCs were cultured and induced in hepatogenic induction medium for 3 and 10 d in custom-made space cell culture hardware. Cell growth was monitored periodically in orbit, and the fixed cells and collected supernatants were retrieved back to the Earth for further analyses. Data indicated that space microgravity improves the differentiating capability of the cells by up-regulating hepatocyte-specific albumin and cytokeratin 18. The resulting cells tended to be maturated, with an in-orbit period of up to 10 d. In space, mechanosensitive molecules of β1-integrin, β-actin, α-tubulin, and Ras homolog gene family member A presented enhanced expression, whereas those of cell-surface glycoprotein CD44, intercellular adhesion molecule 1, vascular cell adhesion molecule 1, vinculin, cell division control protein 42 homolog, and Rho-associated coiled-coil kinase yielded reduced expression. Also observed in space were the depolymerization of actin filaments and the accumulation of microtubules and vimentin through the altered expression and location of focal adhesion complexes, Rho guanosine 5'-triphosphatases, as well as the enhanced exosome-mediated mRNA transfer. This work furthers the understanding of the underlying mechanisms of space microgravity in directing hepatogenic differentiation of BMSCs.-Lü, D., Sun, S., Zhang, F., Luo, C., Zheng, L., Wu, Y., Li, N., Zhang, C., Wang, C., Chen, Q., Long, M. Microgravity-induced hepatogenic differentiation of rBMSCs on board the SJ-10 satellite.

Stem Cells from Cryopreserved Human Dental Pulp Tissues Sequentially Differentiate into Definitive Endoderm and Hepatocyte-Like Cells in vitro

We previously described a novel tissue cryopreservation protocol to enable the safe preservation of various autologous stem cell sources. The present study characterized the stem cells derived from long-term cryopreserved dental pulp tissues (hDPSCs-cryo) and analyzed their differentiation into definitive endoderm (DE) and hepatocyte-like cells (HLCs) in vitro. Human dental pulp tissues from extracted wisdom teeth were cryopreserved as per a slow freezing tissue cryopreservation protocol for at least a year. Characteristics of hDPSCs-cryo were compared to those of stem cells from fresh dental pulps (hDPSCs-fresh). hDPSCs-cryo were differentiated into DE cells in vitro with Activin A as per the Wnt3a protocol for 6 days. These cells were further differentiated into HLCs in the presence of growth factors until day 30. hDPSCs-fresh and hDPSCs-cryo displayed similar cell growth morphology, cell proliferation rates, and mesenchymal stem cell character. During differentiation into DE and HLCs in vitro, the cells flattened and became polygonal in shape, and finally adopted a hepatocyte-like shape. The differentiated DE cells at day 6 and HLCs at day 30 displayed significantly increased DE- and hepatocyte-specific markers at the mRNA and protein level, respectively. In addition, the differentiated HLCs showed detoxification and glycogen storage capacities, indicating they could share multiple functions with real hepatocytes. These data conclusively show that hPDSCs-cryo derived from long-term cryopreserved dental pulp tissues can be successfully differentiated into DE and functional hepatocytes in vitro. Thus, preservation of dental tissues could provide a valuable source of autologous stem cells for tissue engineering.

Are Adipose-Derived Stem Cells From Liver Falciform Ligaments Another Possible Source of Mesenchymal Stem Cells?

Falciform ligaments in the liver are surrounded by adipose tissue. We investigated the capability of adipose-derived stem cells from human liver falciform ligaments (hLF-ADSCs) to differentiate into hepatic-type cells and confirmed the functional capacity of the cells. Mesenchymal stem cells (MSCs) were isolated from the liver falciform ligament and abdominal subcutaneous adipose tissue in patients undergoing partial hepatectomy for liver disease. Cells were cultivated in MSC culture medium. Properties of MSCs were confirmed by flow cytometry, RT-PCR analysis, immunocytochemistry assays, and multilineage differentiation. Hepatic induction was performed using a three-step differentiation protocol with various growth factors. Morphology, capacity for expansion, and characteristics were similar between hLF-ADSCs and adipose-derived stem cells from human abdominal subcutaneous adipose tissue (hAS-ADSCs). However, hematopoietic- and mesenchymal-epithelial transition (MET)-related surface markers (CD133, CD34, CD45, and E-cadherin) had a higher expression in hLF-ADSCs. The hepatic induction marker genes had a higher expression in hLF-ADSCs on days 7 and 10 after the hepatic induction. Albumin secretion was similar between hLF-ADSCs and hAS-ADSCs at 20 days after the hepatic induction. The hLF-ADSCs had a different pattern of surface marker expression relative to hAS-ADSCs. However, proliferation, multilineage capacity, and hepatic induction were similar between the cell types. Accordingly, it may be a useful source of MSCs for patients with liver disease.