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1.
Mol Biotechnol ; 2024 May 02.
Article in English | MEDLINE | ID: mdl-38696100

ABSTRACT

Si Ni San combined with Astragalus (SNSQ) has demonstrated significant efficacy in the treatment of hepatic fibrosis (HF), as confirmed by clinical practice. However, its pharmacological mechanism remains unclear. This study employs network pharmacology to identify key targets and proteins for molecular docking. Additionally, animal experiments were conducted to validate the network pharmacology results, providing further insights into the mechanism of SNSQ in treating HF. Effective compounds of SNSQ were screened from the Traditional Chinese Medicine Systems Pharmacology (TCMSP) and Encyclopedia of Traditional Chinese Medicine (ETCM) databases. Molecular formula structures of these effective compounds were obtained from the PubChem database. Partial target proteins with a probability greater than 0.6 were sourced from the SWISS database. Uniprot IDs corresponding to these target proteins were retrieved from the SUPERPRED database. The remaining target proteins of the compounds were obtained from the Uniprot database based on the Uniprot IDs. The drug target proteins were then summarized. Target points related to HF were selected from the GeneCards and OMIM databases. Common target points were identified in the Venn diagram and imported into Cytoscape 3.9.1 software to construct the "SNSQ-effective compound-target pathway-HF" network. AutoDock software was used for molecular docking of compounds and target proteins with high-degree values. The common target points underwent GO function enrichment and KEGG pathway enrichment analysis using the DAVID database. An HF rat model was established, and serum AST and ALT activities were measured. The Hyp assay kit was utilized to detect the Hyp content in liver tissue. To the transcription levels of pro-inflammatory factors (IL-1ß, TNF-α, IL-6) and anti-inflammatory factors (IL-10, TGF-ß1, IL-4) in rat serum and liver.IL-1ß, TNF-α, IL-10, and TGF-ß1 were chosen for validation through ELISA. Western blotting and qRT-PCR were used to assess the expression of related proteins, namely NFKB1, NF-κBp65, NF-κBp50, α-SMA, and Col-1 in liver tissue. qRT-PCR was also employed to study the expression of ECM synthesis and proliferation-related genes, including Cyclin D1, TIMP1, COL1A1 in HSC-T6 cells and rat liver tissue, as well as the inhibition of the ECM-related gene MMP13 in HSC-T6 cells and rat liver tissue. A total of 16 valid compounds were predicted, with kaempferol, sitosterol, and isorhamnetin exhibiting high-degree values. KEGG enrichment analysis revealed that the target genes of SNSQ were enriched in multiple pathological pathways, with the NF-Kappa B signaling pathway being predominant. Molecular docking simulations indicated strong affinities between SNSQ's primary components-kaempferol, sitosterol, isorhamnetin-and NFKB1. Experimental results demonstrated significant reductions in AST, ALT, and Hyp levels in the SNSQ group. Pro-inflammatory factors (IL-1ß, TNF-ɑ) were markedly reduced, while anti-inflammatory factors (IL-10, TGF-ß1) were substantially increased. The protein expression and transcription levels of α-SMA and Col-1 were significantly decreased, whereas those of NFKB1, NF-κBp65, and NF-κBp50 were notably elevated. mRNA expression levels of Cyclin D1, TIMP1, COL1A1 in HSC-T6 cells and rat liver tissue were significantly decreased, whereas MMP13 mRNA expression level was significantly increased. Treatment of HF with SNSQ involves multiple targets and pathways, with a close association with the overexpression of NFKB1 and activation of the NF-Kappa B signaling pathway. Its mechanism is closely linked to the activation of inflammatory responses, HSC activation, and proliferation.

2.
Biochem J ; 479(19): 2013-2034, 2022 10 14.
Article in English | MEDLINE | ID: mdl-36094147

ABSTRACT

The opportunistic bacterium Pseudomonas aeruginosa secretes the quorum-sensing molecule N-(3-oxododecanoyl)-l-homoserine lactone (C12) to co-ordinate gene expression profiles favorable for infection. Recent studies have demonstrated that high concentrations of C12 impair many aspects of host cell physiology, including mitochondrial function and cell viability. The cytotoxic effects of C12 are mediated by the lactonase enzyme, Paraoxonase 2 (PON2), which hydrolyzes C12 to a reactive metabolite. However, the influence of C12 on host cell physiology at concentrations observed in patients infected with P. aeruginosa is largely unknown. Since the primary site of P. aeruginosa infections is the mammalian airway, we sought to investigate how PON2 modulates the effects of C12 at subtoxic concentrations using immortalized murine tracheal epithelial cells (TECs) isolated from wild-type (WT) or PON2-knockout (PON2-KO) mice. Our data reveal that C12 at subtoxic concentrations disrupts mitochondrial bioenergetics to hinder cellular proliferation in TECs expressing PON2. Subtoxic concentrations of C12 disrupt normal mitochondrial network morphology in a PON2-dependent manner without affecting mitochondrial membrane potential. In contrast, higher concentrations of C12 depolarize mitochondrial membrane potential and subsequently trigger caspase signaling and apoptotic cell death. These findings demonstrate that different concentrations of C12 impact distinct aspects of host airway epithelial cell physiology through PON2 activity in mitochondria.


Subject(s)
Homoserine , Quorum Sensing , 4-Butyrolactone/analogs & derivatives , Animals , Aryldialkylphosphatase/genetics , Aryldialkylphosphatase/metabolism , Aryldialkylphosphatase/pharmacology , Caspases/metabolism , Epithelial Cells/metabolism , Homoserine/metabolism , Homoserine/pharmacology , Lactones/metabolism , Lactones/pharmacology , Mammals/metabolism , Mice , Mitochondria/metabolism , Pseudomonas aeruginosa/metabolism
3.
Reprod Toxicol ; 77: 137-142, 2018 04.
Article in English | MEDLINE | ID: mdl-29526646

ABSTRACT

Numerous studies have been conducted to understand the molecular mechanisms controlling mammalian secondary palate development such as growth, reorientation and fusion. However, little is known about the signaling factors regulating palate initiation. Mouse fibroblast growth factor (FGF) receptor 2 gene (Fgfr2) is expressed on E11.5 in the palate outgrowth within the maxillary process, in a region that is responsible for palate cell specification and shelf initiation. Fgfr2 continues to express in palate on E12.5 and E13.5 in both epithelial and mesenchymal cells, and inactivation of Fgfr2 expression in mesenchymal cells using floxed Fgfr2 allele and Osr2-Cre leads to cleft palate at various stages including reorientation, horizontal growth and fusion. Notably, some mutant embryos displayed no sign of palate shelf formation suggesting that FGF receptor 2 mediated FGF signaling may play an important role in palate initiation.


Subject(s)
Palate/growth & development , Receptor, Fibroblast Growth Factor, Type 2/genetics , Animals , Cleft Palate/genetics , Female , Loss of Function Mutation , Male , Mesenchymal Stem Cells/metabolism , Mice , Palate/cytology , Palate/metabolism
4.
Zhongguo Zhen Jiu ; 37(7): 779-783, 2017 Jul 12.
Article in Chinese | MEDLINE | ID: mdl-29231556

ABSTRACT

The characteristics and principles of acupoint selection in auricular plaster therapy for hypertension were explored. By searching CNKI (search time from 1950 to November of 2015), VIP database (search time from 1989 to November of 2015) and WanFang Database (search time from 1983 to November of 2015), the clinical research literature regarding auricular plaster therapy for hypertension was collected, and frequency statistics method was used for analysis. As a result, totally 117 articles were included. The auricular points with frequency from high to low were Jiangyagou, Shenmen (TF4), Gan (CO12), Xin (CO15), Shen (CO10), Jiaogan (AH6a), Pizhixia (AT4), Jiangyadian and Neifenmi. The TCM syndromes with frequency from high to low were excessive accumulation of phlegm-dampness syndrome, upper hyperactivity of liver yang syndrome, yin deficiency and yang hyperactivity syndrome and excessive liver-fire syndrome. In conclusion, based on cross-reference of TCM and modern medicine combination of zangfu and meridians differentiation and valuing the auricular points from clinical experience, the auricular plaster therapy for hypertension was characterized with "treating the principal and subordinate symptoms simultaneously and respectively" and "differentiation-based selection of auricular points to regulate zangfu", which could fully take the anti-hypertension advantages of non-pharmacotherapy.


Subject(s)
Acupuncture Points , Acupuncture, Ear/methods , Hypertension/therapy , Humans , Yang Deficiency/therapy , Yin Deficiency/therapy
5.
Zhongguo Zhen Jiu ; 37(11): 1157-61, 2017 Nov 12.
Article in Chinese | MEDLINE | ID: mdl-29354950

ABSTRACT

OBJECTIVE: To observe the effects of acupuncture combined with medication on circadian rhythm of blood pressure in patients with essential hypertension. METHODS: Sixty-four patients of essential hypertension were randomly divided into an observation group and a control group, 32 cases in each group. All the patients maintained original treatment (taking antihypertensive medication); the patients in the observation group were treated with acupuncture method of "Huoxue Sanfeng, Shugan Jianpi", once a day, five times per week, for totally 6 weeks (30 times). The circadian rhythm of blood pressure and related dynamic parameters were observed before and after treatment in the two groups. RESULTS: (1) The differences of daytime average systolic blood pressure (dASBP), daytime average diastolic blood pressure (dADBP), nighttime average systolic blood pressure (nASBP) and circadian rhythm of systolic blood pressure before and after treatment were significant in the observation group (all P<0.05); the differences of circadian rhythm of blood pressure and related dynamic parameters before and after treatment were insignificant in the control group (all P>0.05). The nASBP and circadian rhythm of systolic blood pressure in the observation group were significantly different from those in the control group (all P<0.05). (2) After the treatment, the spoon-shaped rate of circadian rhythm of blood pressure in the observation group was higher than that in the control group (P<0.05). CONCLUSION: The acupuncture combined with medication could effectively improve the circadian rhythm of blood pressure and related dynamic parameters in patients with essential hypertension.


Subject(s)
Acupuncture Therapy/methods , Blood Pressure/physiology , Circadian Rhythm/physiology , Essential Hypertension/therapy , Humans
6.
Dev Growth Differ ; 58(6): 522-9, 2016 Aug.
Article in English | MEDLINE | ID: mdl-27273137

ABSTRACT

During mouse gastrulation, the primitive streak is formed on the posterior side of the embryo. Cells migrate out of the primitive streak to form the future mesoderm and endoderm. Fate mapping studies revealed a group of cell migrate through the proximal end of the primitive streak and give rise to the extraembryonic mesoderm tissues such as the yolk sac blood islands and allantois. However, it is not clear whether the formation of a morphological primitive streak is required for the development of these extraembryonic mesodermal tissues. Loss of the Cripto gene in mice dramatically reduces, but does not completely abolish, Nodal activity leading to the absence of a morphological primitive streak. However, embryonic erythrocytes are still formed and assembled into the blood islands. In addition, Cripto mutant embryos form allantoic buds. However, Drap1 mutant embryos have excessive Nodal activity in the epiblast cells before gastrulation and form an expanded primitive streak, but no yolk sac blood islands or allantoic bud formation. Lefty2 embryos also have elevated levels of Nodal activity in the primitive streak during gastrulation, and undergo normal blood island and allantois formation. We therefore speculate that low level of Nodal activity disrupts the formation of morphological primitive streak on the posterior side, but still allows the formation of primitive streak cells on the proximal side, which give rise to the extraembryonic mesodermal tissues formation. Excessive Nodal activity in the epiblast at pre-gastrulation stage, but not in the primitive streak cells during gastrulation, disrupts extraembryonic mesoderm development.


Subject(s)
Mesoderm/cytology , Mesoderm/embryology , Animals , Epidermal Growth Factor/genetics , Epidermal Growth Factor/metabolism , Left-Right Determination Factors/genetics , Left-Right Determination Factors/metabolism , Membrane Glycoproteins/genetics , Membrane Glycoproteins/metabolism , Mice , Mice, Mutant Strains , Neoplasm Proteins/genetics , Neoplasm Proteins/metabolism , Nodal Protein/genetics , Nodal Protein/metabolism , Repressor Proteins/genetics , Repressor Proteins/metabolism
7.
J Dev Biol ; 3(1): 2-10, 2015 Mar.
Article in English | MEDLINE | ID: mdl-27134830

ABSTRACT

The effect of strain background on gene function in growth and development has been well documented. However, it has not been extensively reported whether the strain background affects the gene expression pattern. Here, we found that the expression of homeobox gene Meox-2 and FGF receptor 1 gene Fgfr1 during mouse palate development is strain-dependent. On the C57B6 inbred background, Meox-2 is expressed in the palatal outgrowth on Embryonic Day 11.5 (E11.5); the expression shifts posteriorly and is restricted to the back of palate on E14.5. On the Swiss Webster outbred background, Meox-2 expression covers both anterior and posterior regions with the same intensity from E12.5 to E14.5. On the Black Swiss background, Meox-2 expression also covers the entire palate A-P axis, but is much weaker in the anterior region on E14.5. Fgfr1 also displays distinct expression patterns in the palatal outgrowth on E11.5 in these three strains. On the Black Swiss outbred background, the expression is restricted to the anterior palatal outgrowth. In marked contrast, the expression in the Swiss Webster outbred strain is located exclusively in the posterior palate outgrowth on E11.5, whereas in the C57B6 inbred strain, the expression is undetectable in the palatal outgrowth on E11.5.

8.
Reprod Toxicol ; 50: 129-33, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25450421

ABSTRACT

Cleft palate is a common birth defect affecting 1 in 700 births. Transforming growth factor-ßs (TGF-ßs) are important signaling molecules, and their functions in murine palate development have received great attention. TGF-ß3 is expressed exclusively in palatal epithelial cells and mediates epithelial fusion, whereas the importance of TGF-ß1 and 2 in palate have not yet been demonstrated in vivo, since inactivation of Tgf-ß1 or Tgf-ß2 genes in mice did not reveal significant palate defects. We hypothesized that TGF-ß1 and TGF-ß2 can compensate each other during palate formation. To test this, we generated Tgf-ß1 and Tgf-ß2 compound mutant mice and found that approximately 40% of [Tgf-ß1(+/-); Tgf-ß2(-/-)] compound mutant embryos display cleft palate on C57 background. In addition, 26% of Tgf-ß2(-/-) embryos on 129 background, but not in C57 or Black Swiss, displayed cleft palate. TGF-ß1 and 2 functions are required for murine palate development in strain-dependent manner.


Subject(s)
Palate/embryology , Transforming Growth Factor beta1/physiology , Transforming Growth Factor beta2/physiology , Animals , Mice , Mice, Inbred C57BL , Species Specificity
9.
Dev Dyn ; 243(12): 1536-43, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25104574

ABSTRACT

BACKGROUND: Transforming growth factor-ß3 (TGF-ß3) plays a central role in mediating secondary palate fusion along the facial midline. However, the mechanisms by which TGF-ß3 functions during secondary palate fusion are still poorly understood. RESULTS: We found that mouse cytokeratin 6α and 17 mRNAs were expressed exclusively in the palate medial edge epithelium on embryonic day 14.5, and this expression was completely abolished in Tgf-ß3 mutant embryos. In contrast, we found that Jagged2 was initially expressed throughout the palate epithelium, but was specifically down-regulated in the medial edge epithelium during palatal fusion. Jagged2 down-regulation was regulated by TGF-ß3, since Jagged2 was persistently expressed in palatal medial edge epithelium in Tgf-ß3 null mutant embryos. Moreover, addition of DAPT, a specific inhibitor of Notch signaling, partially rescued the fusion defects in Tgf-ß3 null mutant palatal shelves. CONCLUSIONS: Based on these results, together with the previous study indicating that the loss of Jagged2 function promotes embryonic oral epithelial fusion, we concluded that TGF-ß3 mediates palate fusion in part by down-regulating Jagged2 expression in palatal medial edge epithelium. In addition, cytokeratin 6α and 17 are two TGF-ß3 downstream target genes in palate medial edge epithelium differentiation.


Subject(s)
Embryo, Mammalian/embryology , Mouth Mucosa/embryology , Palate/embryology , Transforming Growth Factor beta3/metabolism , Animals , Calcium-Binding Proteins/genetics , Calcium-Binding Proteins/metabolism , Cell Line , Embryo, Mammalian/cytology , Intercellular Signaling Peptides and Proteins/genetics , Intercellular Signaling Peptides and Proteins/metabolism , Keratin-6/biosynthesis , Keratin-6/genetics , Keratins/biosynthesis , Keratins/genetics , Membrane Proteins/genetics , Membrane Proteins/metabolism , Mice , Mice, Mutant Strains , Palate/cytology , Serrate-Jagged Proteins , Transforming Growth Factor beta3/genetics
10.
Int J Dev Biol ; 58(9): 713-7, 2014.
Article in English | MEDLINE | ID: mdl-25896208

ABSTRACT

Recent studies have shown that mouse palatal mesenchymal cells undergo regional specification along the anterior-posterior (A-P) axis defined by anterior Shox2 and Msx1 expression and posterior Meox2 expression. A-P regional specification of the medial edge epithelium, which is directly responsible for palate fusion, has long been proposed, but it has not yet been demonstrated due to the lack of regional specific markers. In this study, we have demonstrated that the palate medial edge epithelium is regionalized along the A-P axis, similar to that for the underlying mesenchyme. Mmp13, a medial edge epithelium specific marker, was uniformly expressed from anterior to posterior in wild-type mouse palatal shelves. Previous studies demonstrated that medial edge epithelium expression of Mmp13 was regulated by TGF-beta3. We have found that the changes in Mmp13 expression in TGF-beta3 knockouts varied along the A-P axis, and can be broken down into three distinct regions. These regions correlated with regional specification of the underlying medial edge mesenchymal cells and timing of palate fusion. Mouse palate medial edge epithelium along the A-P axis can be divided into different regions according to the differential response to the loss of TGF-beta3.


Subject(s)
Embryo, Mammalian/cytology , Epithelium/embryology , Mesoderm/embryology , Mouth Mucosa/embryology , Palate/embryology , Animals , Embryo, Mammalian/metabolism , Epithelium/metabolism , Gene Expression Regulation, Developmental , In Situ Hybridization , Matrix Metalloproteinase 13/genetics , Mesoderm/metabolism , Mice , Mice, Inbred C57BL , Palate/metabolism , Transforming Growth Factor beta3/physiology
11.
Int J Dev Biol ; 57(9-10): 793-7, 2013.
Article in English | MEDLINE | ID: mdl-24307303

ABSTRACT

Vertebrate cardiac progenitor cells are initially allocated in two distinct domains, the first and second heart fields. It has been demonstrated that first heart field cells give rise to the myocardial cells in the left ventricle and part of the atria, whereas second heart field cells move into the developing heart tube and contribute to the myocardium of the outflow tract and right ventricle and the majority of atria. In this study, we have examined the expression of the mouse Cripto gene and the lineage of Cripto-expressing cells, focusing on its relationship with cardiac myocyte differentiation. The mouse Cripto gene is initially expressed at late head fold (LHF) stages in the cardiac crescent region, known as the first heart field; later in the medial region of the early heart tube, and by embryonic day 8.5, it is localized to the outflow tract. Using a Cripto-LacZ allele, we found that Cripto- expressing progeny cells contribute to the myocardium of the entire outflow tract and right ventricle, as well as to a majority of cells within the left ventricle. In contrast, no Cripto- expressing progeny cells were found in the atria or atrio-ventricular canal. Therefore, Cripto is transiently expressed in early differentiating myocardial cells of the left ventricle, right ventricle and outflow tract between LHF stages and E8.5. Cripto expression is subsequently downregulated as cells undergo further differentiation.


Subject(s)
Epidermal Growth Factor/genetics , Heart Ventricles/embryology , Membrane Glycoproteins/genetics , Myocytes, Cardiac/metabolism , Neoplasm Proteins/genetics , Animals , Biomarkers, Tumor/biosynthesis , Biomarkers, Tumor/genetics , Cell Differentiation , Epidermal Growth Factor/biosynthesis , Gene Expression Regulation, Developmental , Heart Atria/embryology , LIM-Homeodomain Proteins/metabolism , Membrane Glycoproteins/biosynthesis , Mice , Myocytes, Cardiac/cytology , Myosin Light Chains/metabolism , Neoplasm Proteins/biosynthesis , RNA, Messenger/biosynthesis , Transcription Factors/metabolism
12.
Dev Biol ; 381(1): 170-8, 2013 Sep 01.
Article in English | MEDLINE | ID: mdl-23747598

ABSTRACT

During mouse gastrulation, cells in the primitive streak undergo epithelial-mesenchymal transformation and the resulting mesenchymal cells migrate out laterally to form mesoderm and definitive endoderm across the entire embryonic cylinder. The mechanisms underlying mesoderm and endoderm specification, migration, and allocation are poorly understood. In this study, we focused on the function of mouse Cripto, a member of the EGF-CFC gene family that is highly expressed in the primitive streak and migrating mesoderm cells on embryonic day 6.5. Conditional inactivation of Cripto during gastrulation leads to varied defects in mesoderm and endoderm development. Mutant embryos display accumulation of mesenchymal cells around the shortened primitive streak indicating a functional requirement of Cripto during the formation of mesoderm layer in gastrulation. In addition, some mutant embryos showed poor formation and abnormal allocation of definitive endoderm cells on embryonic day 7.5. Consistently, many mutant embryos that survived to embryonic day 8.5 displayed defects in ventral closure of the gut endoderm causing cardia bifida. Detailed analyses revealed that both the Fgf8-Fgfr1 pathway and p38 MAP kinase activation are partially affected by the loss of Cripto function. These results demonstrate a critical role for Cripto during mouse gastrulation, especially in mesoderm and endoderm formation and allocation.


Subject(s)
Endoderm/metabolism , Epidermal Growth Factor/physiology , Gastrulation , Gene Expression Regulation, Developmental , Membrane Glycoproteins/physiology , Mesoderm/metabolism , Neoplasm Proteins/physiology , Alleles , Animals , Epidermal Growth Factor/genetics , Fibroblast Growth Factor 8/metabolism , Gene Expression Profiling , Membrane Glycoproteins/genetics , Mice , Mutation , Neoplasm Proteins/genetics , Primitive Streak/metabolism , Receptor, Fibroblast Growth Factor, Type 1/metabolism , p38 Mitogen-Activated Protein Kinases/metabolism
13.
Dev Dyn ; 239(7): 2110-7, 2010 Jul.
Article in English | MEDLINE | ID: mdl-20549719

ABSTRACT

The formation of mammalian secondary palate requires a series of developmental events such as growth, elevation, and fusion. Despite recent advances in the field of palate development, the process of palate elevation remains poorly understood. The current consensus on palate elevation is that the distal end of the vertical palatal shelf corresponds to the medial edge of the elevated horizontal palatal shelf. We provide evidence suggesting that the prospective medial edge of the vertical palate is located toward the interior side (the side adjacent to the tongue), instead of the distal end, of the vertical palatal shelf and that the horizontal palatal axis is generated through palatal outgrowth from the side of the vertical palatal shelf rather than rotating the pre-existing vertical axis orthogonally. Because palate elevation represents a classic example of embryonic tissue re-orientation, our findings here may also shed light on the process of tissue re-orientation in general.


Subject(s)
Mesoderm/embryology , Palate/embryology , Animals , Mesoderm/cytology , Mice , Palate/cytology
14.
Cell Tissue Res ; 333(1): 29-38, 2008 Jul.
Article in English | MEDLINE | ID: mdl-18470539

ABSTRACT

Cleft palate is a common birth defect that involves disruptions in multiple developmental steps such as growth, differentiation, elevation, and fusion. Medial edge epithelial (MEE) differentiation is essential for palate fusion. An important question is whether the MEE differentiation that occurs during fusion is induced by palate shelf contact or is programmed intrinsically by the palate shelf itself. Here, we report that the loss of Zfhx1a function in mice leads to a cleft palate phenotype that is mainly attributable to a delay in palate elevation. Zfhx1a encodes a transcription regulatory protein that modulates several signaling pathways including those activated by members of the transforming growth factor-beta (TGF-beta) superfamily. Loss of Zfhx1a function in mice leads to a complete cleft palate with 100% penetrance. Zfhx1a mutant palatal shelves display normal cell differentiation and proliferation and are able to fuse in an in vitro culture system. The only defect detected was a delay of 24-48 h in palatal shelf elevation. Using the Zfhx1a mutant as a model, we studied the relationship between MEE differentiation and palate contact/adhesion. We found that down-regulation of Jag2 expression in the MEE cells, a key differentiation event establishing palate fusion competence, was independent of palate contact/adhesion. Moreover, the expression of several key factors essential for fusion, such as TGF-beta3 and MMP13, was also down-regulated at embryonic stage 16.5 in a contact-independent manner, suggesting that differentiation of the medial edge epithelium was largely programmed through an intrinsic mechanism within the palate shelf.


Subject(s)
Epithelial Cells/cytology , Epithelium/embryology , Homeodomain Proteins/analysis , Palate/cytology , Palate/embryology , Transcription Factors/analysis , Animals , Cell Differentiation/genetics , Cell Proliferation , Cells, Cultured , Cleft Palate/embryology , Cleft Palate/genetics , Gene Expression Regulation, Developmental , In Situ Hybridization , Mice , Mice, Mutant Strains
15.
Development ; 133(17): 3341-7, 2006 Sep.
Article in English | MEDLINE | ID: mdl-16887819

ABSTRACT

Malformations in secondary palate fusion will lead to cleft palate, a common human birth defect. Palate fusion involves the formation and subsequent degeneration of the medial edge epithelial seam. The cellular mechanisms underlying seam degeneration have been a major focus in the study of palatogenesis. Three mechanisms have been proposed for seam degeneration: lateral migration of medial edge epithelial cells; epithelial-mesenchymal trans-differentiation; and apoptosis of medial edge epithelial cells. However, there is still a great deal of controversy over these proposed mechanisms. In this study, we established a [Rosa26<-->C57BL/6] chimeric culture system, in which a Rosa26-originated ;blue' palatal shelf was paired with a C57BL/6-derived ;white' palatal shelf. Using this organ culture system, we observed the migration of medial edge epithelial cells to the nasal side, but not to the oral side. We also observed an anteroposterior migration of medial edge epithelial cells, which may play an important role in posterior palate fusion. To examine epithelial-mesenchymal transdifferentiation during palate fusion, we bred a cytokeratin 14-Cre transgenic line into the R26R background. In situ hybridization showed that the Cre transgene is expressed exclusively in the epithelium. However, beta-galactosidase staining gave extensive signals in the palatal mesenchymal region during and after palate fusion, demonstrating the occurrence of an epithelial-mesenchymal transdifferentiation mechanism during palate fusion. Finally, we showed that Apaf1 mutant mouse embryos are able to complete palate fusion without DNA fragmentation-mediated programmed cell death, indicating that this is not essential for palate fusion in vivo.


Subject(s)
Apoptosis/physiology , Cell Differentiation/physiology , Cell Movement/physiology , Epithelial Cells/physiology , Palate/embryology , Animals , Chimera , Epithelial Cells/cytology , In Situ Hybridization , Integrases/genetics , Keratins/genetics , Mesoderm/cytology , Mice , Mice, Inbred C57BL , Mice, Transgenic , Organ Culture Techniques , Palate/cytology
16.
Dev Dyn ; 235(2): 539-46, 2006 Feb.
Article in English | MEDLINE | ID: mdl-16284941

ABSTRACT

Cleft palate represents a common human congential disease involving defects in the development of the secondary palate. Major steps in mammalian palatogenesis include vertical growth, elevation, and fusion of the palate shelves. Our current study with the homeobox gene Meox-2 during mouse secondary palate development reveals a novel postfusion-based mechanism for cleft palate. Meox-1 and Meox-2 are two functionally related homeobox genes playing important roles in somitogenesis and limb muscle differentiation. We found that the expression of Meox-2, not Meox-1, marks the specification of early mouse palatal mesenchymal cells in the maxillary processes at embryonic day 11.5 (E11.5). From E12.5 to E15.5, the expression of Meox-2 occupies only the posterior part of the palate, providing an early molecular marker for the anterior-posterior polarity in mouse secondary palate formation. A total of 35.3% of Meox-2-/- (n = 17) and 25.5% of Meox-2+/- (n = 55) mouse embryos display a cleft palate phenotype at E15.5, indicating that the reduction of Meox-2 function is associated with susceptibility to cleft palate. Unlike previously reported clefts, none of the clefts found in Meox-2 mutants contain any epithelial sheets in the medial edge areas, and detailed examination revealed that the clefts resulted from the breakdown of newly fused palates. This article is the first report of a gene required to maintain adherence of the palatal shelves after fusion.


Subject(s)
Cleft Palate/metabolism , Cleft Palate/pathology , Homeodomain Proteins/metabolism , Animals , Cleft Palate/embryology , Cleft Palate/genetics , Gene Expression Regulation, Developmental/genetics , Goosecoid Protein/genetics , Homeodomain Proteins/genetics , Mice , Mice, Inbred C57BL , Mice, Knockout , Mutation/genetics , Organ Culture Techniques , Phenotype
17.
Dev Dyn ; 235(2): 547-53, 2006 Feb.
Article in English | MEDLINE | ID: mdl-16284942

ABSTRACT

The Tgif gene encodes a homeodomain protein that functions as a transforming growth factor beta (TGF-beta) repressor by binding to Smad2. Mutations in the TGIF gene are associated with human holoprosencephaly, a common birth defect caused by the failure of anterior ventral midline formation. However, Smad2-mediated TGF-beta signaling in the axial mesendoderm has been demonstrated to be essential for ventral midline formation, and loss of a Smad2 antagonist should in principle promote rather than inhibit ventral midline formation. This suggests a more complex mechanism for the function of TGIF in controlling ventral midline formation. To explore the role of TGIF in ventral forebrain formation and patterning, we investigated Tgif expression and function during mouse development by in situ hybridization and gene targeting. We found that Tgif is highly expressed in the anterior neural plate, consistent with the proposed neural differentiation model in which TGF-beta suppression is required for normal neural differentiation. This result suggests a possible role for Tgif in anterior neural differentiation and patterning. However, targeted disruption of the Tgif gene during mouse development does not cause any detectable defects in development and growth. Both histological examination and gene expression analysis showed that Tgif-/- embryos have a normal ventral specification in the central nervous system, including the forebrain region. One interpretation of these results is that the loss of TGIF function is compensated by other TGF-beta antagonists such as c-Ski and SnoN during vertebrate anterior neural development.


Subject(s)
Body Patterning , Embryo, Mammalian/metabolism , Gene Expression Regulation, Developmental/genetics , Homeodomain Proteins/metabolism , Repressor Proteins/metabolism , Animals , Embryo, Mammalian/embryology , Gene Deletion , Homeodomain Proteins/genetics , Mice , Mice, Knockout , Repressor Proteins/genetics , Spinal Cord/embryology , Spinal Cord/metabolism
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