SMAD2 overexpression rescues the TGF-β3 null mutant mice cleft palate by increased apoptosis

A novel IRF6 gene mutation impacting the regulation of TGFβ2-AS1 in the TGFβ pathway: A mechanism in the development of Van der Woude syndrome

Several mutations in the IRF6 gene have been identified as a causative link to VWS. In this investigation, whole-exome sequencing (WES) and Sanger sequencing of a three-generation pedigree with an autosomal-dominant inheritance pattern affected by VWS identified a unique stop-gain mutation-c.748C>T:p.R250X-in the IRF6 gene that co-segregated exclusively with the disease phenotype. Immunofluorescence analysis revealed that the IRF6-p.R250X mutation predominantly shifted its localization from the nucleus to the cytoplasm. WES and protein interaction analyses were conducted to understand this mutation's role in the pathogenesis of VWS. Using LC-MS/MS, we found that this mutation led to a reduction in the binding of IRF6 to histone modification-associated proteins (NAA10, SNRPN, NAP1L1). Furthermore, RNA-seq results show that the mutation resulted in a downregulation of TGFβ2-AS1 expression. The findings highlight the mutation's influence on TGFβ2-AS1 and its subsequent effects on the phosphorylation of SMAD2/3, which are critical in maxillofacial development, particularly the palate. These insights contribute to a deeper understanding of VWS's molecular underpinnings and might inform future therapeutic strategies.

Genetic variants in BCL-2 family genes influence the risk of non-syndromic cleft lip with or without cleft palate

BACKGROUND

The BCL-2 family is crucial for cell death regulation and is involved in development, tissue homeostasis, and immunity. This study aimed to investigate the association between genetic variants in BCL-2 family genes and non-syndromic cleft lip with or without cleft palate (NSCL/P) risk.

METHODS

A two-stage case-control study was conducted in this association study. Gene-based analysis using Multi-marker Analysis of GenoMic Annotation was performed in the first stage cohort, which included 565 cases and 1269 controls. A logistic regression model was employed to assess the effect of single nucleotide polymorphisms (SNPs) on susceptibility to NSCL/P. Candidate SNPs were replicated by extra dbGaP case-parent trios. Haploreg, RegulomeDB, and UCSC Genome Browser were used to identify enhancer effects of promising SNPs. Bulk RNA sequencing data obtained from the Gene Expression Omnibus was used to identify co-expressed genes. Single-cell RNA sequencing dataset was used to infer the cell population of the candidate gene. The "Monocle" package was used to analyze the pseudotime cell trajectories.

RESULTS

Rs3943258 located in the enhancer region was associated with the risk of NSCL/P (Pmeta  = 5.66 × 10-04 ) and exhibited an eQTL effect for BCL2 (P = 3.96 × 10-02 ). Co-expression and pathway enrichment analysis revealed that genes related to Bcl2 were significantly enriched in the PI3K-Akt signaling pathway, MAPK signaling pathway, and Wnt signaling pathway. Five cell clusters were identified in single-cell RNA sequencing, and Bcl2 was mainly located in the mesenchyme.

CONCLUSION

The rs3943258 located within BCL2 was probably related to NSCL/P susceptibility.

Associations between the proliferation of palatal mesenchymal cells, Tgfβ2 promoter methylation, Meg3 expression, and Smad signaling in atRA-induced cleft palate

All-trans retinoic acid (atRA) is a teratogen that can induce cleft palate formation. During palatal development, murine embryonic palate mesenchymal (MEPM) cell proliferation is required for the appropriate development of the palatal frame, with Meg3 serving as a key regulator of the proliferative activity of these cells and the associated epithelial-mesenchymal transition process. DNA methylation and signaling via the TGFβ/Smad pathway are key in regulating embryonic development. Here, the impact of atRA on MEPM cell proliferation and associations between Tgfβ2 promoter methylation, Meg3, and signaling via the Smad pathway were explored using C57BL/6 N mice treated with atRA (100 mg/kg) to induce fetal cleft palate formation. Immunohistochemistry and BrdU assays were used to detect MEPM proliferation and DNA methylation assays were performed to detect Tgfβ2 promoter expression. These analyses revealed that atRA suppressed MEPM cell proliferation, promoted the upregulation of Meg3, and reduced the levels of Smad2 and Tgfβ2 expression phosphorylation, whereas Tgfβ2 promoter methylation was unaffected. RNA immunoprecipitation experiments indicated that the TgfβI receptor is directly targeted by Meg3, suggesting that the ability of atRA to induce cleft palate may be mediated through the Tgfβ/Smad signaling pathway.

Spatiotemporal Expression and Functional Analysis of miRNA-22 in the Developing Secondary Palate

OBJECTIVE

Normal development of the embryonic orofacial region requires precise spatiotemporal coordination between numerous genes. MicroRNAs represent small, single-stranded, non-coding molecules that regulate gene expression. This study examines the role of microRNA-22 (miR-22) in murine orofacial ontogeny.

METHODS

Spatiotemporal and differential expression of miR-22 (mmu-miR-22-3p) within the developing secondary palate was determined by in situ hybridization and quantitative real-time PCR, respectively. Bioinformatic approaches were used to predict potential mRNA targets of miR-22 and analyze their association with cellular functions indispensable for normal orofacial ontogeny. An in vitro palate organ culture system was used to assess the role of miR-22 in secondary palate development.

RESULTS

There was a progressive increase in miR-22 expression from GD12.5 to GD14.5 in palatal processes. On GD12.5 and GD13.5, miR-22 was expressed in the future oral, nasal, and medial edge epithelia. On GD14.5, miR-22 expression was observed in the residual midline epithelial seam (MES), the nasal epithelium and the mesenchyme, but not in the oral epithelium. Inhibition of miR-22 activity in palate organ cultures resulted in failure of MES removal. Bioinformatic analyses revealed potential mRNA targets of miR-22 that may play significant roles in regulating apoptosis, migration, and/or convergence/extrusion, developmental processes that modulate MES removal during palatogenesis.

CONCLUSIONS

Results from the current study suggest a key role for miR-22 in the removal of the MES during palatogenesis and that miR-22 may represent a potential contributor to the etiology of cleft palate.

Comprehensive analysis of plasma miRNA and related ceRNA network in non-syndromic cleft lip and/or palate

BACKGROUND

Non-syndromic cleft lip and/or palate (NSCL/P) is a common maxillofacial birth defect, and the etiology of which is complex and still unclear. Accumulating studies indicate that long non-coding RNAs(lncRNAs) and microRNAs(miRNAs) play important roles in NSCL/P. However, the potential regulatory associations remain largely unknown. In this study, we screened differentially expressed miRNAs and constructed competing endogenous RNA (ceRNA) networks to lay a foundation for further research on the regulatory mechanism of ncRNAs in NSCL/P.

METHODS

NSCL/P plasma RNA was analyzed by miRNA sequencing. The bioinformatics database, GEO and STRING database, GO and KEGG enrichment analysis and Cytoscape software were used to analyze and screen lncRNAs and mRNAs potentially related to differential miRNAs. The expression levels of lncRNA, miRNA and mRNA in ceRNA network were detected by RT-qPCR.

RESULTS

In NSCL/P plasma samples, there were 47 differentially expressed miRNAs in CPO group and 36 differentially expressed miRNAs in CL/P group. GO and KEGG enrichment analysis showed that cell cycle, cell response to DNA damage stimulation, and the TGF-βsignaling pathway were relevant to the formation of NSCL/P. The RT-qPCR results showed that the expression levels of lncRNA NEAT1, hsa-miR-130 b-3p, hsa-miR-212-3p, hsa-miR-200 b-3p and SMAD2 were different in NSCL/P.

CONCLUSIONS

We found that differentially expressed miR-212-3p, miR-200 b-3p and miR-130 b-3p may be involved in the pathogenesis of cleft palate by regulating related target genes.

Co-Culture of Bone Marrow Mesenchymal Stem Cells Regulates the Fibrotic Response of Endometrial Stromal Cells

This study explored the protective effects and mechanisms of bone marrow mesenchymal stem cells (BMSCs) on the fibrotic response of endometrial stromal cells. The endometrial cells were isolated from intrauterine adhesions (IUA) patients and assigned into control group, TGF-β1 group, BMSC group which was co-cultured with BMSCs in presence of TGF-β1; Exo group (treated with BMSCs-originated exosomes); Exo-inhibitor group (treated with exosome-specific inhibitors) followed by analysis of α-SMA and Vimentin level, cell viability and expression of TGFBR2, TGFβ-1, Fibronectin (FN), α-SMA, Collagen 1α1 (Col1a1), Smad2/3 and p-Smad2/3. After TGF-β1 treatment, cells exhibited higher expression of p-Smad2/3, TGFBR2, FN, TGF-SMA and COL1A1 along with reduced cell proliferation. However, BMSCs-originated exosomes or co-culture with BMSCs reversed these changes which could be inverted by exosome-specific inhibitors. In conclusion, BMSCs-originated exosomes and BMSCs exerted an anti-fibrosis effect, which was possibly through regulation of TGFβ1/Smad2/Smad3 signalling pathway in endometrial stromal cells.

A unique form of collective epithelial migration is crucial for tissue fusion in the secondary palate and can overcome loss of epithelial apoptosis

Tissue fusion frequently requires the removal of an epithelium that intervenes distinct primordia to form one continuous structure. In the mammalian secondary palate, a midline epithelial seam (MES) forms between two palatal shelves and must be removed to allow mesenchymal confluence. Abundant apoptosis and cell extrusion support their importance in MES removal. However, genetically disrupting the intrinsic apoptotic regulators BAX and BAK within the MES results in complete loss of cell death and cell extrusion, but successful removal of the MES. Novel static- and live-imaging approaches reveal that the MES is removed through streaming migration of epithelial trails and islands to reach the oral and nasal epithelial surfaces. Epithelial trail cells that express the basal epithelial marker ΔNp63 begin to express periderm markers, suggesting that migration is concomitant with differentiation. Live imaging reveals anisotropic actomyosin contractility within epithelial trails, and genetic ablation of actomyosin contractility results in dispersion of epithelial collectives and failure of normal MES migration. These findings demonstrate redundancy between cellular mechanisms of morphogenesis, and reveal a crucial and unique form of collective epithelial migration during tissue fusion.

Summary: Multiple cellular processes mediate secondary palate fusion, including a unique form of streaming collective epithelial migration driven by pulsatile actomyosin contractility.

Correlation between TGF-β2/3 promoter DNA methylation and Smad signaling during palatal fusion induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin

2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is a persistent organic pollutant that is strongly associated with a number of human diseases and birth defects, including cleft palate. Transforming growth factor (TGF) plays a significant role during mammalian palatogenesis. However, the epigenetic mechanism of transforming growth factors in the process of TCDD-induced cleft palate is unclear. The purpose of this research was to investigate the relationship and potential mechanism between TGF-β2/3 promoter DNA methylation and Smad signaling during TCDD-induced cleft palate. Pregnant C57BL/6N mice were exposed to 64 µg/kg TCDD on gestational day 10 (GD10) to establish the cleft palate model and palatal tissues of embryos were collected on GD13, GD14, and GD15 for subsequent experiments. TGF-β2/3 mRNA expression, TGF-β2/3 promoter methylation, and Smad signaling molecules expression were assessed in the palate of the two groups. The results showed that the incidence of cleft palate was 94.7% in the TCDD-treated group whereas no cleft palate was found in the control group. TCDD-treated group altered specific CpG sites of TGF-β2/3 promoter methylation. Compared to the control group, the proliferation of mouse embryonic palate mesenchymal stromal cells (MEPM), the expressions of TGF-β2/3, p-Smad2, and Smad4 were all reduced, while the expression of Smad7 was significantly increased in the atAR group. Smad signaling was downregulated by TCDD. Therefore, we suggest that TGF-β2/3 promoter methylation and Smad signaling may be involved in TCDD-induced cleft palate formation in fetal mice.

Long noncoding RNA ZFAS1 suppresses chondrocytes apoptosis via miR-302d-3p/SMAD2 in osteoarthritis

Osteoarthritis (OA) seriously affects people's quality of life due to joint pain, stiffness, disability, and dyskinesia worldwide. Long noncoding RNA zinc finger antisense 1 (ZFAS1) is downregulated and tightly associated with proliferation, migration, apoptosis, and matrix synthesis of chondrocyte in OA. However, the molecular mechanisms of ZFAS1 in OA remain unknown. The expression correlation between ZFAS1, miR-302d-3p, and SMAD2 in OA tissues was analyzed by Pearson correlation analysis. ZFAS1 was a lower expression, and expedited proliferation and repressed apoptosis of chondrocytes. MiR-302d-3p was a direct target of ZFAS1. MiR-302d-3p hindered proliferation and facilitated apoptosis of chondrocytes. MiR-302d-3p partially reversed the effect of ZFAS1 on proliferation and apoptosis of chondrocytes. SMAD2 was positively regulated by the ZFAS1/miR-302d-3p. MiR-302d-3p-mediated proliferation and apoptosis were partly abrogated by targeting SMAD2. ZFAS1 promoted chondrocytes proliferation and repressed apoptosis possibly by regulating miR-302d-3p/SMAD2 axis, providing a potential target for OA treatment.

Identification and Comparative Analysis of Long Non-coding RNAs in High- and Low-Fecundity Goat Ovaries During Estrus

The ovary is the most important reproductive organ in goats and directly affects the fecundity. Long non-coding RNAs (lncRNAs) are involved in the biological process of oocyte maturation. However, in the context of reproduction in goats, few studies have explored the regulation of lncRNAs. Therefore, we herein used the ovaries of high and low fecundity Leizhou black goats to identify differentially expressed lncRNAs (DElncRNAs) by high-throughput RNA sequencing; moreover, we analyzed the target genes of lncRNAs by functional annotation to explore the role of DElncRNAs in ovarian development. Twenty DElncRNAs were identified, of which six were significantly upregulated and 14 were significantly downregulated in high fecundity goats. Gene Ontology analyses suggested that MSTRG.3782 positively influences the expression of the corresponding gene API5, exerting regulative effects on the development of follicles, through which litter size might show variations. The target gene KRR1 of ENSCHIT00000001883 is significantly enriched in cell components, and ENSCHIT00000001883 may regulate cell growth and thus affect follicular development. Further, as per Kyoto Encyclopedia of Genes and Genomes pathway analyses, MSTRG.2938 was found to be significantly enriched, and we speculate that MSTRG.2938 could regulate ribosomal biogenesis in the pre-snoRNP complex as well as cell transformation in eukaryotes. Quantitative real-time PCR results were consistent with sequencing data. To conclude, our research results indicate that some lncRNAs play a key role in regulating follicle development and cell growth during goat’ s ovarian development.

Effects of miR‑210‑3p on the erythroid differentiation of K562 cells under hypoxia

GATA binding protein 1 (GATA-1) is one of the most important hematopoietic transcription factors in the production of blood cells, such as platelets, eosinophils, mast cells and erythrocytes. GATA-1 regulates the participation of microRNA (miRNAs/miRs) in erythroid differentiation under normoxia. However, GATA-1 expression and the regulation of miR-210-3p in the context of erythroid differentiation under hypoxia remain unknown. The present study examined the expression levels of GATA-1 and miR-210-3p in the model of erythroid differentiation in K562 cells under hypoxia, and determined the effects of GATA-1, miR-210-3p and SMAD2 on erythroid differentiation through lentivirus transfection experiments. The present study detected increased GATA-1 expression under hypoxia. Moreover, miR-210-3p was identified as a positive regulator of erythroid differentiation, which was upregulated both during erythroid differentiation and in GATA-1 overexpression experiments under hypoxia. Importantly, in the K562 cell model of erythroid differentiation under hypoxia, miR-210-3p was upregulated in a GATA-1-dependent manner. Using a double luciferase reporter assay, miR-210-3p was identified as a downstream target of GATA-1-mediated regulation of erythropoiesis. Gain- or loss-of-function analysis of miR-210-3p identified its importance in erythroid differentiation. Furthermore, it was found that SMAD2 may be a downstream target gene for miR-210-3p. Bioinformatics predictions suggested that SMAD2 mediated miR-210-3p-induced regulation of erythroid differentiation. Collectively, the present study provides novel insights into the miRNA regulation of erythroid differentiation.

TGF beta -1, -2 and -3 in the modulation of fibrosis in the cornea and other organs

The TGF beta-1, -2 and -3 isoforms are transcribed from different genes but bind to the same receptors and signal through the same canonical and non-canonical signal transduction pathways. There are numerous regulatory mechanisms controlling the action of each isoform that include the organ-specific cells producing latent TGF beta growth factors, multiple effectors that activate the isoforms, ECM-associated SLRPs and basement membrane components that modulate the activity and localization of the isoforms, other interactive cytokine-growth factor receptor systems, such as PDGF and CTGF, TGF beta receptor expression on target cells, including myofibroblast precursors, receptor binding competition, positive and negative signal transduction effectors, and transcription and translational regulatory mechanisms. While there has long been the view that TGF beta-1and TGF beta-2 are pro-fibrotic, while TGF beta-3 is anti-fibrotic, this review suggests that view is too simplistic, at least in adult tissues, since TGF beta-3 shares far more similarities in its modulation of fibrotic gene expression with TGF beta-1 and TGF beta-2, than it does differences, and often the differences are subtle. Rather, TGF beta-3 should be seen as a fibro-modulatory partner to the other two isoforms that modulates a nuanced and better controlled response to injury. The complex interplay between the three isoforms and numerous interactive proteins, in the context of the cellular milieu, controls regenerative non-fibrotic vs. fibrotic healing in a response to injury in a particular organ, as well as the resolution of fibrosis, when that occurs.

The cleft palate candidate gene BAG6 supports FoxO1 acetylation to promote FasL-mediated apoptosis during palate fusion

BACKGROUND

Cleft palate is a common craniofacial defect, which occurs when the palate fails to fuse during development. During fusion, the palatal shelves migrate towards the embryonic midline to form a seam. Apoptotic elimination of medial edge epithelium (MEE) cells along this seam is required for the completion of palate fusion.

METHODS

Whole exome sequencing (WES) of six Chinese cleft palate families was applied to identify novel cleft palate-associated gene variants. Palatal fusion and immunofluorescence studies were performed in a murine palatal shelf organ culture model. Gene and protein expression were analyzed by qPCR and immunoblotting in murine MEE cells during seam formation in vivo. Mechanistic immunoprecipitation studies were performed in murine MEE cells in vitro.

RESULTS

WES identified Bcl-2 associated anthanogene 6 (BAG6) as a novel cleft palate-associated gene. In murine MEE cells, we discovered upregulation of Bag6 and the transcription factor forkhead box protein O1 (FoxO1) during seam formation in vivo. Using a palatal shelf organ culture model, we demonstrate that nuclear-localized Bag6 enhances MEE cell apoptosis by promoting p300's acetylation of FoxO1, thereby promoting transcription of the pro-apoptotic Fas ligand (FasL). Subsequent gain- and loss-of-function studies in the organ culture model demonstrated that FasL is required for Bag6/acFoxO1-mediated activation of pro-apoptotic Bax/caspase-3 signaling, MEE apoptosis, and palate fusion. Palatal shelf contact was shown to enhance Bag6 nuclear localization and upregulate nuclear acFoxO1 in MEE cells.

CONCLUSIONS

These findings demonstrate that nuclear-localized Bag6 and p300 co-operatively enhance FoxO1 acetylation to promote FasL-mediated MEE apoptosis during palate fusion.