Transforming Growth Factor-β Signaling Pathway Research Articles

Upregulating MMP-1 in carcinoma-associated fibroblasts reduces the efficacy of Taxotere on breast cancer synergized by Collagen IV.

Chemotherapy is an important comprehensive treatment for breast cancer, which targets micro-environment of tumors as well as their characterisitcs. A previous microarray analysis revealed that matrix metalloproteinase (MMP)-1 was highly upregulated in carcinoma-associated fibroblasts (CAFs) prior to and following treatment with Taxotere under co-culture conditions. However, whether the chemotherapeutic effects of Taxotere were influenced by the changes in MMP-1 remained unclear. The purpose of the present study was to investigate the impact and mechanism of CAFs in regulating the efficacy of Taxotere on breast cancer cells. CAFs isolated from primary invasive ductal human breast tumors following surgical resection, were used in co-culture with MDA-MB-231 cells to simulate the tumor micro-environment. Following the addition of Taxotere, changes in MMP-1 gene and protein expression were assessed by reverse transcription-quantitative polymerase chain reaction and western blot analysis, respectively. Proliferation, invasion and apoptosis assays revealed that when MMP-1 was upregulated in CAFs, the therapeutic efficacy of Taxotere was reduced in breast cancer cells. Chemosensitivity was significantly increased when MMP-1 expression was inhibited by GM6001. In addition, Collagen IV was upregulated in CAFs following chemotherapy and protected breast cancer cells against chemotherapeutic side effects. Collagen IV expression significantly decreased, as well as MMP-1 expression when GM6001 was added. Proliferation and invasion assays demonstrated that the exogenous addition of Collagen IV weakend the chemotherapeutic effect of Taxotere on breast tumor cells. Overall, the results revealed that in CAFs, MMP-1 synergized with Collagen IV as a key gene in regulating the chemotherapeutic effect of Taxotere on breast tumor cells and served an important role in reducing the efficacy of Taxotere on breast cancer, potentially via the transforming growth factor-β signaling pathway. These fidings provide a theoretical basis for the mechanism of CAFs in reducing the chemotherapeutic effect of Taxotere on breast cancer cells and a novel approach for enhancing the chemosensitivity of tumors.

Identifying differentially expressed long non-coding RNAs in PBMCs in response to the infection of multidrug-resistant tuberculosis

PurposeThe aim of this paper was to identify differentially expressed long non-coding RNAs (lncRNAs) in peripheral blood mononuclear cells (PBMCs) influenced by the infection of multidrug-resistant tuberculosis (MDR-TB).Materials and methodsIncRNA and mRNA expression profiles in PBMCs derived from healthy controls (HCs) and individuals with MDR-TB and drug-sensitive tuberculosis (DS-TB) were analyzed and compared by microarray assay. Six lncRNAs were randomly selected for validation by using real-time quantitative polymerase chain reaction (RT-qPCR). The biological functions and signaling pathways affected by the differentially expressed mRNAs were investigated by using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway-based approaches.ResultsCompared with the HC group, 1,429 lncRNAs (983 mRNAs) and 2,040 lncRNAs (1,407 mRNAs) were identified to be deregulated in the MDR-TB group and in the DS-TB group, respectively, and 1,511 lncRNAs and 1,047 mRNAs were identified to be differentially expressed in both MDR-TB and DS-TB groups. Between the three groups, 22 lncRNAs and 38 mRNAs were found deregulated. Most deregulated lncRNAs were from intergenic regions (~55% of the total), natural antisense to protein-coding loci (~32% of the total), or intronic antisense to protein-coding loci (~5% of the total). Significantly enriched signaling pathways regulated by the deregulated mRNAs were mainly associated with natural killer cell-mediated cytotoxicity, antigen processing and presentation, graft-vs-host disease, the transforming growth factor-β signaling pathway, and the Hippo signaling pathway.ConclusionThis study is the first to report differentially expressed lncRNAs in PBMCs in response to MDR-TB infection. It revealed that some lncRNAs might be associated with regulating host immune response to MDR-TB infection. Further elucidation of the potential of these deregulated lncRNAs in MDR-TB and its reactivation requires further study.

VHL status regulates transforming growth factor-β signaling pathways in renal cell carcinoma.

To evaluate the role of pVHL in the regulation of TGF-β signaling pathways in clear cell renal cell carcinoma (ccRCC) as well as in non-ccRCC; the expression of pVHL, and the TGF-β pathway components and their association with clinicopathological parameters and patient’s survival were explored. Tissue samples from 143 ccRCC and 58 non-ccRCC patients were examined by immunoblot. ccRCC cell lines were utilized for mechanistic in-vitro studies. Expression levels of pVHL were significantly lower in ccRCC compared with non-ccRCC. Non-ccRCC and ccRCC pVHL-High expressed similar levels of pVHL. Expression of the TGF-β type I receptor (ALK5) and intra-cellular domain were significantly higher in ccRCC compared with non-ccRCC. In non-ccRCC, expressions of ALK5-FL, ALK5-ICD, pSMAD2/3, and PAI-1 had no association with clinicopathological parameters and survival. In ccRCC pVHL-Low, ALK5-FL, ALK5-ICD, pSMAD2/3, and PAI-1 were significantly related with tumor stage, size, and survival. In ccRCC pVHL-High, the expression of PAI-1 was associated with stage and survival. In-vitro studies revealed that pVHL interacted with ALK5 to downregulate its expression through K48-linked poly-ubiquitination and proteasomal degradation, thus negatively controlling TGF-β induced cancer cell invasiveness. The pVHL status controls the ALK5 and can thereby regulate the TGF-β pathway, aggressiveness of tumors, and survival of the ccRCC and non-ccRCC patients.

Progress of the role of serine-threonine kinase receptor-associated protein in tumorigenesis

Serine-threonine kinase receptor-associated protein (STRAP) is initially identified as a putative inhibitor of the canonical transforming growth factor-β (TGF-β) signaling pathway by Dr. Datta. Because the Smad-dependent TGF-β pathway negatively regulates cellular growth, and STRAP has been found overexpressed in various cancers, like colorectal, lung and breast carcinoma, early functional studies suggested that STRAP behaves as an oncogene. As the progress of new studies on the biological function of STRAP, it is becoming clear that STRAP has diversity function to regulate multiple signaling pathways. Due to the absence of enzymatic activity, it appears that STRAP influences multiple biological processes through direct associations with other cellular proteins within the β propeller of its WD40 domain. In this review, we will comprehensively describe the progress of the role of STRAP in tumorigenesis. Key words: Serine-threonine kinase receptor-associated protein; Transforming growth factor-β; β-catenin; Nonmetastatic gene 23-H1; Apoptosis signal-regulating kinase 1; Tumorigenesis

Bioinformatics identification of dysregulated microRNAs in triple negative breast cancer based on microRNA expression profiling

Triple negative breast cancer (TNBC) accounts for approximately 15–20% of all breast cancer cases and is usually more aggressive with a poorer clinical outcome compared with other breast cancer subtypes. Evidence of the involvement of microRNAs (miRNAs) in cancer has provided an opportunity for the development of novel effective therapeutic targets in TNBC. In the present study, the miRNA expression profiles of the human breast cancer cell line, MDA-MB-231, and MCF-7 cells, was evaluated by using miRNA microarray analysis. A total of 107 differentially expressed miRNAs (57 upregulated and 50 downregulated) were identified in MDA-MB-231 cells compared with MCF-7 cells. Five prominently dysregulated miRNAs (miR-200c-3p, miR-221-3p, miR-222-3p, miR-192-5p and miR-146a) were further confirmed by reverse transcription-quantitative polymerase chain reaction. In addition, gene ontology analysis and pathway enrichment analysis revealed that the dysregulated miRNAs and predicted targets were found to be involved in the mitogen-activated protein kinase, Wnt, and transforming growth factor-β signaling pathways, which were known to contribute to TNBC progression and metastasis. Finally, miRNA gene network analyses suggested that miR-200c may serve as a crucial miRNA in breast cancer. Taken together, these findings may provide a comprehensive view of the function of aberrant miRNAs involved in TNBC, and dysregulated miRNAs hold promise as potential biomarkers and therapeutic targets for patients with TNBC.

Building and Crossing the Translational Bridge: 2016Alopecia Areata Research Summit Highlights.

Alopecia areata (AA) is a common autoimmune skin disease that results in the loss of hair on the scalp and elsewhere on the body and affects over 146 million people worldwide at some point in their lives. Founded in 1981, the National Alopecia Areata Foundation is a nonprofit organization that supports research to find a cure or acceptable treatment for AA, supports those with the disease, and educates the public about AA. The National Alopecia Areata Foundation conducts research summits every 2 years to review progress and create new directions in its funded and promoted research. The Foundation brings together scientists from all disciplines to get a broad and varied perspective. These AA research summits are part of the Foundation's main strategic initiative, the AA Treatment Development Program, to enhance the understanding of AA and accelerate progress toward a viable treatment.

Therapeutic effects of histone deacetylase inhibitors on kidney disease.

Increasing evidence has shown the involvement of histone deacetylases (HDACs) in the development and progression of various renal diseases, highlighting its inhibition as a promising therapeutic strategy to prevent kidney diseases. Accordingly, numerous studies have shown that HDAC inhibitors protect the kidneys from various diseases through their effects on multiple pathways, such as suppression of transforming growth factor-β signaling pathway and nuclear factor-κB signaling pathways, augmentation of apoptosis, and inhibition of angiogenesis. To develop more effective and less toxic isoform-selective HDAC inhibitors and further improve clinical outcomes, it is necessary to identify and understand the mechanisms involved in the pathogenesis and progression of renal diseases. This review focuses on the roles of HDAC inhibitors and the mechanisms involved in their therapeutic effects in experimental models of kidney diseases including glomerulosclerosis, tubulointerstitial fibrosis, glomerular and tubulointerstitial inflammation, lupus nephritis, polycystic kidney disease, and renal cell carcinoma (RCC).

Co-expression network analysis of lncRNAs and mRNAs in OPTN-silenced cells.

The aim of the present study was to reveal the role of long noncoding RNAs(lncRNAs) in the regulation of the pathogenesis of optineurin(OPTN)-silenced cells. The microarray data set GSE12452 was re-annotated using the non-coding RNA function annotation server to identify differentially expressed lncRNAs. Weighted correlation network analysis was used to construct an lncRNA-lncRNA co-expression network and identify co-expression modules. Three OPTN small interfering RNAs (siRNAs) were transiently transfected into HeLa cells. Reverse transcription‑quantitative polymerase chain reaction(RT-qPCR) and western blot analysis were used to detect OPTN expression and select the most effective OPTNsiRNA to construct stably transfected cells. RT-qPCR was used to quantify the identified lncRNAs in the OPTN-silenced cells. The potential functions of these modules were explored by the functional enrichment of the corresponding co-expressed genes. A total of 3,495lncRNAs were re-annotated. Of these, matrix metalloprotease12 andRP11-169D4.1 were upregulated, and RP1-212P9.2 was downregulated. The results of the RT-qPCR analysis of RP1-212P9.2 andRP11‑169D4.1 were consistent with the re-annotated data in the OPTN‑silenced cells. GeneOntology analyses indicated that the biological functions of the mRNAs co-expressed with these lncRNAs were associated with gene product regulation, and neuronal migration, polarity and differentiation. In addition, Kyoto Encyclopedia of Genes and Genomes analysis indicated that the two validated lncRNAs were associated with the transforming growth factor-β signaling pathway and the apoptosis pathway, respectively. In conclusion, the abnormal lncRNAs identified in OPTN-silenced cells indicate that lncRNAs may contribute to the molecular pathogenesis of OPTN-associated diseases.

Epithelial-to-Mesenchymal Stem Cell Transition in a Human Organ: Lessons from Lichen Planopilaris

Epithelial-to-mesenchymal transition (EMT) is critical for embryonic development and wound healing, and occurs in fibrotic disease and carcinoma. Here, we show that EMT also occurs within the bulge, the epithelial stem cell (eSC) niche of human scalp hair follicles, during the inflammatory permanent alopecia, lichen planopilaris. We show that a molecular EMT signature can be experimentally induced in healthy human eSCs in situ by antagonizing E-cadherin, combined with transforming growth factor-β1, epidermal growth factor, and IFN-γ administration, which to our knowledge has not been reported previously. Moreover, induction of EMT within primary human eSCs can be prevented and even partially reversed exvivo by peroxisome proliferator-activated receptor-γ agonists, likely through suppression of the transforming growth factor-β signaling pathway. Furthermore, we show that peroxisome proliferator-activated receptor-γ agonists also attenuates the EMT signature even in lesional lichen planopilaris hair follicles exvivo. We introduce lichen planopilaris as a model disease for pathological EMT in human adult eSCs, report a preclinical assay for therapeutically manipulating eSC EMT within a healthy human (mini-)organ, and show that peroxisome proliferator-activated receptor-γ agonists are promising agents for suppressing and partially reversing EMT in human hair follicles eSCs exvivo, including in lichen planopilaris.

Common mechanism of pathogenesis in various types of metastatic osteosarcoma.

The present study aimed to investigate the common metastatic mechanism in various types of metastatic osteosarcoma (OS). Gene expression profiles generated from the metastatic OS KHOS and KRIB cell lines and the non-metastatic OS HOS cell line were compared. Two groups of differentially expressed genes (DEGs) between KHOS or KRIB and HOS were screened (P<0.01 and |fold change| ≥2) and then underwent Gene Ontology (GO) and pathway enrichment analyses. Subsequently, the protein-protein interaction (PPI) network was constructed and the subnetwork was mined. Furthermore, overlapping DEGs of these two groups were identified and pathway enrichment and regulatory network analyses were performed. A total of 1,552 and 1,330 DEGs from KHOS vs. HOS and KRIB vs. HOS were obtained, respectively. GO and pathway enrichment analyses of DEGs between KRIB and HOS, including anatomical structure morphogenesis and focal adhesion, were similar to those between KHOS and HOS. Vascular endothelial growth factor A and epidermal growth factor receptor were hub nodes in the PPI network for KHOS and KRIB. Subnetworks of these two groups were similar. In addition, 421 upregulated and 595 downregulated overlapping genes were enriched in the mitogen-activated protein kinase and transforming growth factor-β signaling pathways. Furthermore, seven vital transcription factors, including hes-related family bHLH transcription factor with YRPW motif 1 (HEY1), were obtained. Overall, different types of metastatic OS were shown to exhibit a similar mechanism of pathogenesis. With the exception of cell adhesion and angiogenesis, recapitulation of the morphogenetic processes facilitates OS tumor formation and metastasis. Genes such as HEY1 are important for metastatic OS. Further studies are required in order to confirm these results.

Construction of a recombinant pIRES2-EGFP-ARTS plasmid and its effect on LX-2 cells.

The inhibition of the activation of hepatic stellate cells (HSCs) and the induction of their apoptosis have been investigated as potential strategies to counteract the development and progression of liver fibrosis. Previous research has suggested that apoptosis-related protein in the transforming growth factor-β signaling pathway (ARTS) may serve a significant role in numerous cell types; however, little is known regarding its roles in HSCs. Total RNA was extracted from LX-2 cells, and the human full-length ARTS gene was obtained by reverse transcription-polymerase chain reaction and inserted into the pIRES2-EGFP cloning vector. Subsequently, the recombinant pIRES2-EGFP-ARTS plasmid was transfected into LX-2 cells by FuGENE 6 transfection reagent, and the expression of ARTS was detected by western blotting and fluorescent microscopy. In addition, the effects of pIRES2-EGFP-ARTS on the activation, apoptosis, viability and migration of LX-2 cells were assessed by western blot analysis, TUNEL staining, an MTT assay, and scratch and Transwell assays, respectively. The present results demonstrated that the pIRES2-EGFP-ARTS vector expressing human ARTS was successfully constructed, and the overexpression of ARTS contributed to enhance the apoptosis and inhibit the activation of human LX-2 HSCs. The present findings suggested that ARTS overexpression may have potential as a novel therapeutic strategy to reverse hepatic fibrosis.

MiR-590 promotes the proliferation of HUMSCs and induces ECM synthesis by targeting Smad7.

MicroRNA (miR)-590 has been established to be a promoter of cell proliferation, migration and invasion, and an inhibitor of apoptosis in numerous cancer cell lines. However, its effects on non-cancer cells remain to be elucidated. miR-590 was transfected into human umbilical cord mesenchymal stem cells (HUMSCs), and the cell proliferation rate was determined using a Cell-Light 5-ethynyl-20-deoxyuridine Apollo 567 kit and the presence of extracellular matrix (ECM) proteins were detected using western blot analysis and immunofluorescence microscopy. Using bioinformatic analysis and dual-luciferase assays, the novel target miR-590 was identified. In addition, the effects of miR-590 on cell proliferation and ECM enhancement were also evaluated. The results of the present study demonstrated that miR-590 interacts directly with the 3′-untranslated region of Mothers Against Decapentaplegic Homolog 7 (Smad7), which is an important factor in transforming growth factor-β signaling pathway. Overexpression of miR-590 downregulated Smad7 expression at the mRNA and protein level, and subsequently resulted in cell proliferation and ECM accumulation. Additionally, the transfection of small interfering RNA targeting Smad7 in HUMSCs produced similar effects on cell proliferation and ECM to the overexpression of miR-590. The results of the present study indicated that miR-590 affects HUMSC proliferation by directly targeting Smad7.

Inhibition of c-Myc expression accounts for an increase in the number of multinucleated cells in human cervical epithelial cells.

The present study aimed to explore the mechanisms by which c-Myc is involved in mitotic catastrophe. HeLa-630 is a cell line stably silenced for c-Myc expression that was established in the laboratory of the School of Radiation Medicine and Protection. Multinucleated cells were observed in this line, and gene expression analysis was utilized to examine differences in gene expression in these cells compared with in the control cells transfected with the control plasmid. Gene ontology analysis was performed for differentially expressed genes. Expression profile analyses revealed that cells with silenced c-Myc exhibited abnormal expression patterns of genes involved in various functions, including the regulation of microtubule nucleation, centrosome duplication, the formation of pericentriolar material, DNA synthesis and metabolism, protein metabolism and the regulation of ion concentrations. Pathway analyses of differentially expressed genes demonstrated that these genes were primarily involved in diverse signal transduction pathways, including not only the adherens junction pathway, the transforming growth factor-β signaling pathway and the Wnt signaling pathway, among others, but also signaling pathways with roles in cytokine and immune regulation. The proportion of multinucleated cells with multipolar spindles was significantly higher in silenced c-Myc cells as compared with the control cells, and this discrepancy became more pronounced following cell irradiation. The inhibition of c-Myc in tumors may account for the radiosensitization of certain tumor cell types.

Therapeutic resistance of breast cancer stem cells and its related signaling pathway

Breast cancer stem cells (CSCs) are the main causes leading to the failure of treatment of breast cancer and play important roles in the progression of breast cancer and drug resistance, which are closely related to the therapeutic resistance of radiotherapy and chemotherapy, and endocrine therapy. The metastatic potential and therapeutic resistance of CSCs are associated with epithelial mesenchymal transition and Hedgehog, Wnt, interleukin-6/signal transduction and tanscriptional activation factor 3, transforming growth factor-β and other signaling pathways. While some of the targeted drugs targeting these signaling pathways are undergoing clinical transformation, which is expected to provide new approach for the clinical treatment of breast cancer. Key words: Breast neoplasms; Neoplastic stem cells; Targeted therapy

Megakaryocytic Smad4 Regulates Platelet Function through Syk and ROCK2 Expression

Smad4, a key transcription factor in the transforming growth factor-β signaling pathway, is involved in a variety of cell physiologic and pathologic processes. Here, we characterized megakaryocyte/platelet-specific Smad4 deficiency in mice to elucidate its effect on platelet function. We found that megakaryocyte/platelet-specific loss of Smad4 caused mild thrombocytopenia and significantly extended first occlusion time and tail bleeding time in mice. Smad4-deficient platelets showed reduced agonist-induced platelet aggregation. Further studies showed that a severe defect was seen in integrin αIIbβ3-mediated bidirectional (inside-out and outside-in) signaling in Smad4-deficient platelets, as evidenced by reduced fibrinogen binding and α-granule secretion, suppressed platelet spreading and clot retraction. Microarray analysis showed that the expression levels of multiple genes were altered in Smad4-deficient platelets. Among these genes, spleen tyrosine kinase (Syk) and Rho-associated coiled-coil containing protein kinase 2 (ROCK2) were downregulated several times as confirmed by quantitative reverse-transcription polymerase chain reaction and immunoblotting. Further research showed that Smad4 directly regulates ROCK2 transcription but indirectly regulates Syk. Megakaryocyte/platelet-specific Smad4 deficiency caused decreased expression levels of Syk and ROCK2 in platelets. These results suggest potential links among Smad4 deficiency, attenuated Syk, and ROCK2 expression and defective platelet activation.

Characterization of microRNAs profiles of induced pluripotent stem cells reprogrammed from human dental pulp stem cells and stem cells from apical papilla

To compare characterization of microRNAs (miRNAs) expression profiles of induced pluripotent stem cells (iPSCs) reprogrammed from human dental pulp stem cells (DPSCs) and stem cells from apical papilla (SCAP) and screen-specific microRNA. Human DPSCs and SCAP were reprogrammed into iPSCs using a Sendai virus vector. Total RNA of human DPSCs-iPSCs and SCAP-iPSCs were extracted. miRNAs were labeled and hybridized. Slides were scanned, and images were imported into GenePix Pro 6.0 for grid alignment and data extraction. Significant differentially expressed miRNAs between the two groups were identified using fold change and P-value and were analyzed. Both human DPSCs and SCAP were successfully reprogrammed into iPSCs. Among miRNA genes analyzed by miRNA microarray, 68 were differentially expressed by more than 10-fold in DPSCs-iPSCs; 37 of these genes were up-regulated, and 31 were down-regulated. In SCAP-iPSCs, 107 genes were differentially expressed by more than 10-fold; 68 were up-regulated, and 39 were down-regulated. In both cells, only miR-302e was up-regulated, whereas 9 miRNAs were down-regulated: miR-29b-3p, miR-181b-5p, miR-4328, miR-22-5p, miR-145-5p, miR-4324, let-7b-5p, miR-181a-5p, and miR-27b-3p. Multiple miRNAs participated in reprogramming of human DPSCs and SCAP into iPSCs. Most miRNAs are related to cell cycle, transforming growth factor-β signaling pathways and epithelial-mesenchymal transition.

Dipeptidyl Peptidase IV as a Prognostic Marker and Therapeutic Target in Papillary Thyroid Carcinoma

Dipeptidyl peptidase IV (DPP4) is overexpressed in thyroid cancer and certain malignancies. Furthermore, DPP4 has been identified as a discriminatory marker for thyroid cancer. However, it remains unclear whether DPP4 expression plays a prognostic role. The aim of this study was to investigate the expression and function of DPP4 in thyroid cancer and the mechanisms involved. We determined the expression of DPP4 by immunohistochemistry in tissue microarrays of thyroid tumors. In vitro functional studies were performed after genetic and pharmacological inhibition of DPP4. Gene expression and pathway analyses were used to identify downstream targets. The therapeutic potential of DPP4 inhibition was evaluated in a mouse xenograft model. High DPP4 expression was associated with extrathyroidal extension (P < 0.001), BRAF mutation (P < 0.001), and advanced tumor stage (P = 0.007) in papillary thyroid cancer. Patients in the high-DPP4 expression group were less likely to be classified as having no evidence of disease at final follow-up (P = 0.042). DPP4 silencing or treatment with DPP4 inhibitors significantly suppressed colony formation, cell migration, and invasion. Analysis of differentially expressed genes after DPP4 knockdown suggested that the transforming growth factor-β signaling pathway is involved. In vivo experiments revealed that sitagliptin treatment reduced tumor growth and xenograft transforming growth factor-β receptor I expression. Increased DPP4 expression is associated with cellular invasion and more aggressive disease in papillary thyroid cancer. Targeting DPP4 may be a therapeutic strategy for DPP4-expressing thyroid cancer.

Genes Associated with Thoracic Aortic Aneurysm and Dissection: An Update and Clinical Implications.

Thoracic aortic aneurysm (TAA) is a lethal disease, with a natural history of enlarging progressively until dissection or rupture occurs. Since the discovery almost 20 years ago that ascending TAAs are highly familial, our understanding of the genetics of thoracic aortic aneurysm and dissection (TAAD) has increased exponentially. At least 29 genes have been shown to be associated with the development of TAAD, the majority of which encode proteins involved in the extracellular matrix, smooth muscle cell contraction or metabolism, or the transforming growth factor-β signaling pathway. Almost one-quarter of TAAD patients have a mutation in one of these genes. In this review, we provide a summary of TAAD-associated genes, associated clinical features of the vasculature, and implications for surgical treatment of TAAD. With the widespread use of next-generation sequencing and development of novel functional assays, the future of the genetics of TAAD is bright, as both novel TAAD genes and variants within the genes will continue to be identified.

MicroRNA-15b silencing inhibits IL-1β-induced extracellular matrix degradation by targeting SMAD3 in human nucleus pulposus cells.

To determine the role of microRNA-15b (miR-15b) in interleukin-1 beta (IL-1β)-induced extracellular matrix (ECM) degradation in the nucleus pulposus (NP). MiR-15b was up-regulated in degenerative NP tissues and in IL-1β-stimulated NP cells, as compared to the levels in normal controls (normal tissue specimens from patients with idiopathic scoliosis). Bioinformatics and luciferase activity analyses showed that mothers against decapentaplegic homolog 3 (SMAD3), a key mediator of the transforming growth factor-β signaling pathway, was directly targeted by miR-15b. Functional analysis demonstrated that miR-15b overexpression aggravated IL-1β-induced ECM degradation in NP cells, while miR-15b inhibition had the opposite effects. Prevention of IL-1β-induced NP ECM degeneration by the miR-15b inhibitor was attenuated by small-interfering-RNA-mediated knockdown of SMAD3. In addition, activation of MAP kinase and nuclear factor-κB up-regulated miR-15b expression and down-regulated SMAD3 expression in IL-1β-stimulated NP cells. MiR-15b contributes to ECM degradation in intervertebral disc degeneration (IDD) via targeting of SMAD3, thus providing a novel therapeutic target for IDD treatment.

Spatial signalling mediated by the transforming growth factor-β signalling pathway during tooth formation

Tooth development relies on sequential and reciprocal interactions between the epithelial and mesenchymal tissues, and it is continuously regulated by a variety of conserved and specific temporal-spatial signalling pathways. It is well known that suspensions of tooth germ cells can form tooth-like structures after losing the positional information provided by the epithelial and mesenchymal tissues. However, the particular stage in which the tooth germ cells start to form tooth-like structures after losing their positional information remains unclear. In this study, we investigated the reassociation of tooth germ cells suspension from different morphological stages during tooth development and the phosphorylation of Smad2/3 in this process. Four tooth morphological stages were designed in this study. The results showed that tooth germ cells formed odontogenic tissue at embryonic day (E) 14.5, which is referred to as the cap stage, and they formed tooth-like structures at E16.5, which is referred to as the early bell stage, and E18.5, which is referred to as the late bell stage. Moreover, the transforming growth factor-β signalling pathway might play a role in this process.