Induction of primitive streak and mesendoderm formation in monolayer hESC culture by activation of TGF-β signaling pathway by Activin B

AbstractHuman embryonic stem cells (hESCs) have the ability to differentiate into all human cells, however controlling the differentiation has always been a challenge. In the present study we have investigated the direct differentiation of hESCs on MEFs by using TGF-β signaling pathway activators Activin A and Activin B. Activation of the TGF-β pathway with Activin B in low serum highly induced primitive streak and mesendoderm formation after 24h, which included up-regulation of SOX 17 and BRACHYURY protein and gene expression. Continuous stimulation with Activin B in 2% serum further induced mesendoderm formation by increased gene expression of Brachyury, SOX17, MEOX and FOX at the same time we found down-regulation of neuroectodermal marker genes. Further, by stimulating the mesodermal cells by BMP-2 we succeeded to induce mesenchymal like cells with high expression of mesenchymal markers including; MEOX, FOX, RUNX2, COL1 and OSTEOPONTIN. In conclusion we have directed the differentiation of hESCs as monolayer to primitive streak like cells with Activin B and further into pure mesoderm and mesenchymal like cells by BMP-2

Curcumin ameliorates experimental autoimmune acute myocarditis in rats as evidenced by decrease in thioredoxin immunoreactivity

This study was performed to investigate the effect of curcumin on cardiac myosin-induced autoimmune myocarditis in rats and the change in thioredoxin (TRX) immunoreactivity in cardiomyocytes following curcumin treatment. Twenty-four six-week-old male Wistar rats were randomly allocated into 4 groups of 6 rats each. Group I received neither curcumin nor myosin. Group II received an oral solution of 1 g/kg/day of curcumin daily, from day 1 to day 21. To induce myocarditis, animals of both group III and group IV were injected by 1 mg of porcine cardiac myosin on days 1 and 8. In addition, animals of group IV received an oral solution of 1 g/kg/day of curcumin daily, from day 1 to day 21. Serum levels of creatine phosphokinase, troponin-T, tumour necrosis factor-alpha and interleukin-6 were estimated. Hearts were processed for histopathological and immunohistochemical studies. Serum biomarkers levels were significantly increased in myocarditis group as compared to other groups. The intake of curcumin significantly reduced the deviation in these markers. Sections of the wall of the heart from myocarditis group were characterised by inflammatory cell infiltration. Most of cardiomyocytes showed pyknotic nuclei and increased sarcoplasmic eosinophilia with strong immunoreactivity for TRX. Sections from myocarditis-curcumin group showed normal architecture with moderate immunoreactivity for TRX. The present study demonstrated that curcumin ameliorates acute myocarditis in rats and encouraged the estimation of serum level of TRX as a relevant indicator for the evaluation of the progress of acute myocarditis

Transgelin is a TGFβ-inducible gene that regulates osteoblastic and adipogenic differentiation of human skeletal stem cells through actin cytoskeleston organization

Regenerative medicine is a novel approach for treating conditions in which enhanced bone regeneration is required. We identified transgelin (TAGLN), a transforming growth factor beta (TGFβ)-inducible gene, as an upregulated gene during in vitro osteoblastic and adipocytic differentiation of human bone marrow-derived stromal (skeletal) stem cells (hMSC). siRNA-mediated gene silencing of TAGLN impaired lineage differentiation into osteoblasts and adipocytes but enhanced cell proliferation. Additional functional studies revealed that TAGLN deficiency impaired hMSC cell motility and in vitro transwell cell migration. On the other hand, TAGLN overexpression reduced hMSC cell proliferation, but enhanced cell migration, osteoblastic and adipocytic differentiation, and in vivo bone formation. In addition, deficiency or overexpression of TAGLN in hMSC was associated with significant changes in cellular and nuclear morphology and cytoplasmic organelle composition as demonstrated by high content imaging and transmission electron microscopy that revealed pronounced alterations in the distribution of the actin filament and changes in cytoskeletal organization. Molecular signature of TAGLN-deficient hMSC showed that several genes and genetic pathways associated with cell differentiation, including regulation of actin cytoskeleton and focal adhesion pathways, were downregulated. Our data demonstrate that TAGLN has a role in generating committed progenitor cells from undifferentiated hMSC by regulating cytoskeleton organization. Targeting TAGLN is a plausible approach to enrich for committed hMSC cells needed for regenerative medicine application

Collagen types I and II distribution: a relevant indicator for the functional properties of articular cartilage in immobilised and remobilised rabbit knee joints

The objective of the present work was to study changes in collagen type I and type II distribution in the articular cartilage of immobilised and remobilised rabbit knee joints. Twenty-four adult male rabbits were divided into three groups. One of the groups was a control group with free movement. The right knee joints of animals of the other two groups were immobilised for 4 weeks, followed by a period of 10 weeks of remobilisation for animals of group 3. Collagen type I and type II in the articular cartilage of tibial medial condyle of the right knee joint were estimated immunohistochemically in all groups. A degenerative process was evident after 4 weeks of immobilisation of rabbit knee joint leading to a partial shift in the density of collagen composition from type II to type I. After a period of 10 weeks of remobilisation, regenerative processes, evidenced by a restoration of collagen type II to normal, proceeded on top of degenerative processes, evidenced by the significantly higher content of collagen type I compared with normal. The present study pointed to the importance of assessment of collagen distribution as a relevant indicator for the functional properties of articular cartilage in immobilised and remobilised joints

Stem cells from human extracted deciduous teeth expanded in foetal bovine and human sera express different paracrine factors after exposure to freshly prepared human serum

Background: The response of stem cells to paracrine factors within the host’s body plays an important role in the regeneration process after transplantation. The aim of this study was to determine the viability and paracrine factor profile of stem cells from human extracted deciduous teeth (SHED) pre-cultivated in media supplemented with either foetal bovine serum (FBS) or pooled human serum (pHS) in the presence of individual human sera (iHS). Methods: SHED (n=3) from passage 4 were expanded in FBS (FBS-SHED) or pHS (pHS-SHED) supplemented media until passage 7. During expansion, the proliferation of SHED was determined. Cells at passage 7 were further expanded in human serum from four individual donors (iHS) for 120 hours followed by assessment of cell viability and profiling of the secreted paracrine factors. Results: Proliferation of SHED was significantly higher (p<0.05) in pHS supplemented media compared to FBS supplemented media. pHS-SHED also maintained their higher proliferation rate compared to FBS-SHED in the presence of iHS. In iHS supplemented media, FBS-SHED expressed significantly higher levels of SDF-1A (p<0.05) after 24 hours compared to pHS-SHED. Similar results were found for HGF (p<0.01), LIF (p<0.05), PDGF-BB (p<0.05), SDF-1A (p<0.01), and IL-10 (p<0.05) when cell culture supernatants from FBS-SHED was profiled 120 hours post-incubation. Conclusion: SHED expanded in pHS instead of FBS have higher proliferative capacity and show an altered secretion profile. Further studies are needed to determine whether these differences could result in better engraftment and regeneration following transplantation