Understanding limb development not only gives insights into the outgrowth and differentiation of the limb, but also has clinical relevance. Limb development begins with two paired limb buds (forelimb and hindlimb buds), which are initially undifferentiated mesenchymal cells tipped with a thickening of the ectoderm, termed the apical ectodermal ridge (AER). As a transitional embryonic structure, the AER undergoes four stages and contributes to multiple axes of limb development through the coordination of signalling centres, feedback loops, and other cell activities by secretory signalling and the activation of gene expression. Within the scope of proximodistal patterning, it is understood that while fibroblast growth factors (FGFs) function sequentially over time as primary components of the AER signalling process, there is still no consensus on models that would explain proximodistal patterning itself. In anteroposterior patterning, the AER has a dual-direction regulation by which it promotes the sonic hedgehog (Shh) gene expression in the zone of polarizing activity (ZPA) for proliferation, and inhibits Shh expression in the anterior mesenchyme. In dorsoventral patterning, the AER activates Engrailed-1 (En1) expression, and thus represses Wnt family member 7a (Wnt7a) expression in the ventral ectoderm by the expression of Fgfs, Sp6/8, and bone morphogenetic protein (Bmp) genes. The AER also plays a vital role in shaping the individual digits, since levels of Fgf4/8 and Bmps expressed in the AER affect digit patterning by controlling apoptosis. In summary, the knowledge of crosstalk within AER among the three main axes is essential to understand limb growth and pattern formation, as the development of its areas proceeds simultaneously.
Animals ; Apoptosis ; Body Patterning ; Bone Morphogenetic Proteins/biosynthesis* ; Developmental Biology ; Ectoderm/metabolism* ; Extremities/embryology* ; Fibroblast Growth Factor 10/metabolism* ; Fibroblast Growth Factors/biosynthesis* ; Gene Expression Regulation ; Hedgehog Proteins/biosynthesis* ; Homeodomain Proteins/biosynthesis* ; Mesoderm/metabolism* ; Mice ; Signal Transduction ; Wnt Proteins/biosynthesis*

Mesp family proteins comprise two members named mesodermal posterior 1 (Mesp1) and mesodermal posterior 2 (Mesp2). Both Mesp1 and Mesp2 are transcription factors and they share an almost identical basic helix-loop-helix motif. They have been shown to play critical regulating roles in mammalian heart and somite development. Mesp1 sits in the core of the complicated regulatory network for generation of cardiovascular progenitors while Mesp2 is central for somitogenesis. Here we summarize the similarities and differences in their molecular functions during mammalian early mesodermal development and discuss possible future research directions for further study of the functions of Mesp1 and Mesp2. A comprehensive knowledge of molecular functions of Mesp family proteins will eventually help us better understand mammalian heart development and somitogenesis as well as improve the production of specific cell types from pluripotent stem cells for future regenerative therapies.
Amino Acid Sequence ; Animals ; Basic Helix-Loop-Helix Transcription Factors ; genetics ; Cell Differentiation ; genetics ; Gene Expression Regulation, Developmental ; Mesoderm ; embryology ; metabolism ; Mice, Knockout ; Molecular Sequence Data ; Pluripotent Stem Cells ; metabolism ; Sequence Homology, Amino Acid

OBJECTIVETo investigate the relationship between endothelial-to-mesenchymal transition (EndMT) and myocardial fibrosis in acute viral myocarditis (VMC).

METHODSTwenty-eight Balb/c mice were randomized into 3 groups: control group (n=8), VMC group(n=10) and intervention group(n=10). Mice in VMC and intervention groups were injected intraperitoneally(i.p) with single dose of coxsackievirus B3, mice in control group were injected with equal amount of viral-free vehicle. In the following day, mice in control and VMC groups were injected i.p with 0.1 ml of saline and intervention group with 0.1 ml of recombinant human bone morphogenetic protein 7(rh-BMP7) at a concentration of 300 μg/kg. The mice hearts were harvested after 7 d, cardiac collagen volume fraction (CVF) was calculated on picrosirius red-stained sections. mRNA and protein expression of TGF-β1, CD31, VE-cadherin, fibroblast special protein 1 (FSP-1) and α-smooth muscle actin (α-SMA) and collagen 1α1 in myocardiac tissues were detected by real-time RT-PCR and Western blot analysis, respectively.

RESULTSCompared to controls, overt fibrosis was presented in necrotic area of myocardium in VMC group. Meanwhile, marked increase of TGF-β1 expression accompanied with EndMT characterized by loss of endothelial phenotype (decreased expression of CD31 and VE-cadherin), gain of mesenchymal proteins (overexpression of FSP-1 and α-SMA) and increased synthesis of collagen was also demonstrated. Both EndMT and cardiac fibrosis were simultaneously reversed by TGF-β1 inhibition.

CONCLUSIONEndMT is involved in cardiac fibrosis in acute viral myocarditis, TGF-β1 might be a main mediator.

Acute Disease ; Animals ; Antigens, CD ; metabolism ; Cadherins ; metabolism ; Collagen ; metabolism ; Coxsackievirus Infections ; metabolism ; pathology ; Disease Models, Animal ; Endothelium ; pathology ; Fibrosis ; Male ; Mesoderm ; pathology ; Mice ; Mice, Inbred BALB C ; Myocarditis ; metabolism ; pathology ; virology ; Myocardium ; metabolism ; pathology ; Transforming Growth Factor beta1 ; metabolism

Actin cytoskeleton has been known to control and/or be associated with chondrogenesis. Staurosporine and cytochalasin D modulate actin cytoskeleton and affect chondrogenesis. However, the underlying mechanisms for actin dynamics regulation by these agents are not known well. In the present study, we investigate the effect of staurosporine and cytochalasin D on the actin dynamics as well as possible regulatory mechanisms of actin cytoskeleton modulation. Staurosporine and cytochalasin D have different effects on actin stress fibers in that staurosporine dissolved actin stress fibers while cytochalasin D disrupted them in both stress forming cells and stress fiber-formed cells. Increase in the G-/F-actin ratio either by dissolution or disruption of actin stress fiber is critical for the chondrogenic differentiation. Cytochalasin D reduced the phosphorylation of cofilin, whereas staurosporine showed little effect on cofilin phosphorylation. Either staurosporine or cytochalasin D had little effect on the phosphorylation of myosin light chain. These results suggest that staurosporine and cytochalasin D employ different mechanisms for the regulation of actin dynamics and provide evidence that removal of actin stress fibers is crucial for the chondrogenic differentiation.
Actin Cytoskeleton/*drug effects ; Actins/metabolism ; Animals ; Cell Differentiation/*drug effects ; Cells, Cultured ; Chickens ; Chondrogenesis/*drug effects ; Cytochalasin D/*pharmacology ; Mesoderm/cytology/drug effects ; Myosin Light Chains/metabolism ; Nucleic Acid Synthesis Inhibitors/*pharmacology ; Phosphorylation ; Staurosporine/*pharmacology ; Stress Fibers/drug effects

OBJECTIVE: To explore the expression and distribution of vimentin in different types of chronic rhinosinusitis and its significance. METHOD: There were four groups including control (10 samples), Eos CRSwNP (10 samples), non-Eos CRSwNP (12 samples) and CRSsNP (10 samples). The expression of vimentin in chronic rhinosinusitis were detected by immunohistochemistry technique. The double-immunofluorescence was used to detect the positive staining of both vimentin and E-cadherin, both of which were the marker of epithelial cells. RESULT: The positive staining of vimentin were observed both in epithelium and lamina propria. The expression of vimentin were found in myofibroblast, endothelium and other mesenchymal cells. The vimentin positive cells in epithelium were epithelial cells but not mesenchymal cells, as they also expressed E-cadherin. CONCLUSION The vimentin positive staining cells distribute in lamina propria and epithelium of both normal nasal mucosa and chronic rhinosinusitis. The positive staining epithelial cells may generate from epithelial-mesenchymal transition. So the vimentin may play an important role in the development of chronic rhinosinusitis.
Adult ; Antigens, CD ; Cadherins ; metabolism ; Chronic Disease ; Epithelial Cells ; metabolism ; Female ; Humans ; Male ; Mesoderm ; cytology ; metabolism ; Middle Aged ; Nasal Mucosa ; metabolism ; Sinusitis ; metabolism ; pathology ; Vimentin ; metabolism ; Young Adult

OBJECTIVETo investigate the role and significance of epithelial-mesenchymal transition (EMT) and its transcriptional regulator Twist1 in the development of the human fetal prostate.

METHODSTwenty-five human fetal prostate specimens at various developmental stages (16-39 weeks) were included in this study. EMT markers, such as E-Cadherin, N-Cadherin and Vimentin, and EMT transcriptional regulator Twist1 were determined by immunohistochemistry, and their relationship with the development of the human fetal prostate was analyzed.

RESULTSE-Cadherin was expressed in the fetal prostate epithelium only, while Vimentin, N-Cadherin and Twist1 in both the epithelium and the stroma. The expression of E-Cadherin gradually increased, but those of Vimentin, N-Cadherin and Twist1 gradually decreased with the gestation stages. No significant changes were observed in the staining patterns of Vimentin, N-Cadherin and Twist1 in the stroma during the whole developmental process.

CONCLUSIONEMT is involved in the development of the human fetal prostate, which may promote epithelial cell motility to form prostatic bud tubules in early gestation stages and boost the differentiation of prostate epithelia in later stages.

Cadherins ; metabolism ; Cell Dedifferentiation ; Epithelial Cells ; metabolism ; Epithelial-Mesenchymal Transition ; Fetal Development ; Humans ; Male ; Mesoderm ; metabolism ; Nuclear Proteins ; metabolism ; Prostate ; embryology ; growth & development ; metabolism ; Twist-Related Protein 1 ; metabolism ; Vimentin ; metabolism

BACKGROUND AND OBJECTIVEIt has been proven that epithelial-mesenchymal transition (EMT) not only correlated with embryonic development but also could promote tumor invasion and metastasis. Transforming growth factor beta-1 (TGF-beta1) has been identified as the main inducer of tumor EMT. The aim of this study was to investigate the effects of TGF-beta1 on EMT and PI3K/AKT signaling pathway in lung adencarcinoma PC9 cells.

METHODSCultured PC9 cells were treated with different concentrations of TGF-beta1 for 48 h. The morphological changes were observed under phase-contrast microscopy; EMT relative marker protein changes were assessed by Western blot and immunoflurescence staining. In addition, the expression of AKT and P-AKT were also measured by Western blot.

RESULTSThe data showed that TGF-beta1 could induce PC9 morphological alteration from epithelial to mesenchymal and upregulate the expression of mesenchymal maker protein Fibronectin. Obviously, the expression of P-AKT was downregulated by TGF-beta1 treatment for 48 h.

CONCLUSIONTGF-beta1 might induce EMT of PC9 cells, accompanied by the changes of PI3K/AKT signaling pathway.

Adenocarcinoma ; metabolism ; pathology ; Blotting, Western ; Cell Differentiation ; drug effects ; Cell Line, Tumor ; Epithelial Cells ; pathology ; Fibronectins ; metabolism ; Humans ; Lung Neoplasms ; metabolism ; pathology ; Mesoderm ; metabolism ; pathology ; Microscopy, Phase-Contrast ; Proto-Oncogene Proteins c-akt ; metabolism ; Signal Transduction ; drug effects ; Transforming Growth Factor beta1 ; pharmacology

OBJECTIVETo investigate the effect of salvianolic-acid B (SA-B) on epithelia-mesenchymal transition in human renal proximal tubular cells (HK2), induced by transforming growth factor beta1 (TGF-beta1).

METHODEpithelia-mesenchymal transition (EMT) was induced with TGF-beta1 in HK2 cultured in vitro. Different concentrations (2, 5, 10, 20 microg x L(-1)) and stimulant periods (12, 24, 48 h) were tried to find the perfect condition for EMT. At the same time bone morphogenetic protein-7 (BMP-7, positive control) and the SA-B intervention were given to observe their effect on EMT. Western blot and immunofluorescent microscopy were used to analyze the expression of E-cadherin and alpha-smooth muscle actin (alpha-SMA) in HK2.

RESULTBMP-7 significantly inhibited the down-regulation of E-cadherin and the up-regulation of alpha-SMA induced by TGF-beta1 (P < 0.05), and SA-B significantly inhibited the up-regulation of alpha-SMA expression induced by TGF-beta1 (P < 0.05), but not the down-regulation of E-cadherin induced by TGF-beta1.

CONCLUSIONSA-B and BMP-7 can inhibit TGF-beta1-induced EMT in HK2. Their common role is to inhibit the up-regulation of alpha-SMA, and the effect of SA-B on the regulation of E-cadherin needs further study to be confirmed.

Benzofurans ; pharmacology ; Bone Morphogenetic Protein 7 ; pharmacology ; Cadherins ; metabolism ; Cell Differentiation ; drug effects ; Cell Line ; Epithelial Cells ; pathology ; Humans ; Mesoderm ; pathology ; Transforming Growth Factor beta1 ; pharmacology

The purpose of this study was to explore the role of epithelial-mesenchymal transition in the pathogenesis of hepatolithiasis. Thirty-one patients with primary hepatolithiasis were enrolled in this study. Expressions of E-cadherin, alpha-catenin, alpha-SMA, vimentin, S100A4, TGF-beta1 and P-smad2/3 in hepatolithiasis bile duct epithelial cells were examined by immunohistochemistry staining. The results showed that the expressions of the epithelial markers E-cadherin and alpha-catenin were frequently lost in hepatolithiasis (32.3% and 25.9% of cases, respectively), while the mesenchymal markers vimentin, alpha-SMA and S100A4 were found to be present in hepatolithiasis (35.5%, 29.0%, and 32.3% of cases, respectively). The increased mesenchymal marker expression was correlated with decreased epithelial marker expression. The expressions of TGF-beta1 and P-smad2/3 in hepatolithiasis were correlated with the expression of S100A4. These data indicate that TGF-beta1-mediated epithelial-mesenchymal transition might be involved in the formation of hepatolithiasis.
Adult ; *Bile Ducts/cytology/metabolism/pathology ; Biological Markers/*metabolism ; Cell Differentiation/*physiology ; Epithelial Cells/cytology/*physiology ; Epithelium/physiology ; Female ; *Gallstones/metabolism/pathology ; Humans ; Liver Diseases/metabolism/*pathology ; Male ; Mesoderm/cytology/*physiology ; Middle Aged

Recently, reactive oxygen species (ROS) have been studied as a regulator of differentiation into specific cell types in embryonic stem cells (ESCs). However, ROS role in human ESCs (hESCs) is unknown because mouse ESCs have been used mainly for most studies. Herein we suggest that ROS generation may play a critical role in differentiation of hESCs; ROS enhances differentiation of hESCs into bi-potent mesendodermal cell lineage via ROS-involved signaling pathways. In ROS-inducing conditions, expression of pluripotency markers (Oct4, Tra 1-60, Nanog, and Sox2) of hESCs was decreased, while expression of mesodermal and endodermal markers was increased. Moreover, these differentiation events of hESCs in ROS-inducing conditions were decreased by free radical scavenger treatment. hESC-derived embryoid bodies (EBs) also showed similar differentiation patterns by ROS induction. In ROS-related signaling pathway, some of the MAPKs family members in hESCs were also affected by ROS induction. p38 MAPK and AKT (protein kinases B, PKB) were inactivated significantly by buthionine sulfoximine (BSO) treatment. JNK and ERK phosphorylation levels were increased at early time of BSO treatment but not at late time point. Moreover, MAPKs family-specific inhibitors could prevent the mesendodermal differentiation of hESCs by ROS induction. Our results demonstrate that stemness and differentiation of hESCs can be regulated by environmental factors such as ROS.
Biological Markers/metabolism ; Cell Differentiation/*drug effects ; Cell Line ; Cell Lineage/*drug effects ; Cells, Cultured ; Down-Regulation/drug effects ; Embryo, Mammalian/cytology/drug effects/metabolism ; Embryonic Stem Cells/*cytology/*drug effects/enzymology ; Endoderm/*cytology/drug effects ; Enzyme Activation/drug effects ; Free Radical Scavengers/pharmacology ; Humans ; Mesoderm/*cytology/drug effects ; Mitogen-Activated Protein Kinases/metabolism ; Pluripotent Stem Cells/cytology/metabolism ; Reactive Oxygen Species/metabolism/*pharmacology ; Up-Regulation/drug effects