Dan Su

All Publications

• Wolf-Hirschhorn syndrome candidate 1<i> (Whsc1)</i> methyltransferase signals<i> via</i> a<i> Pitx2-miR-23/24</i> axis to effect tooth development JOURNAL OF BIOLOGICAL CHEMISTRY Su, D., Eliason, S., Sun, Z., Shao, F., Amendt, B. A. 2023; 299 (11): 105324

  Abstract

  Wolf-Hirschhorn syndrome (WHS) is a developmental disorder attributed to a partial deletion on the short arm of chromosome 4. WHS patients suffer from oral manifestations including cleft lip and palate, hypodontia, and taurodontism. WHS candidate 1 (WHSC1) gene is a H3K36-specific methyltransferase that is deleted in every reported case of WHS. Mutation in this gene also results in tooth anomalies in patients. However, the correlation between genetic abnormalities and the tooth anomalies has remained controversial. In our study, we aimed to clarify the role of WHSC1 in tooth development. We profiled the Whsc1 expression pattern during mouse incisor and molar development by immunofluorescence staining and found Whsc1 expression is reduced as tooth development proceeds. Using real-time quantitative reverse transcription PCR, Western blot, chromatin immunoprecipitation, and luciferase assays, we determined that Whsc1 and Pitx2, the initial transcription factor involved in tooth development, positively and reciprocally regulate each other through their gene promoters. miRNAs are known to regulate gene expression posttranscriptionally during development. We previously reported miR-23a/b and miR-24-1/2 were highly expressed in the mature tooth germ. Interestingly, we demonstrate here that these two miRs directly target Whsc1 and repress its expression. Additionally, this miR cluster is also negatively regulated by Pitx2. We show the expression of these two miRs and Whsc1 are inversely correlated during mouse mandibular development. Taken together, our results provide new insights into the potential role of Whsc1 in regulating tooth development and a possible molecular mechanism underlying the dental defects in WHS.

  View details for DOI 10.1016/j.jbc.2023.105324

  View details for Web of Science ID 001105392300001

  View details for PubMedID 37806494

  View details for PubMedCentralID PMC10656234

• Role of Tbr2-Irx1 transcription cascade in the development of ipRGC subtypes Kiyama, T., Chen, C., Su, D., Eliason, S., Amendt, B., Mao, C. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2023

  View details for Web of Science ID 001053795602248

• Exploring microRNAs in craniofacial regenerative medicine BIOCHEMICAL SOCIETY TRANSACTIONS Su, D., Swearson, S., Krongbaramee, T., Sun, H., Hong, L., Amendt, B. A. 2023; 51 (2): 841-854

  Abstract

  microRNAs (miRs) have been reported over the decades as important regulators in bone development and bone regeneration. They play important roles in maintaining the stem cell signature as well as regulating stem cell fate decisions. Thus, delivering miRs and miR inhibitors to the defect site is a potential treatment towards craniofacial bone defects. However, there are challenges in translation of basic research to clinics, including the efficiency, specificity, and efficacy of miR manipulation methods and the safety of miR delivery systems. In this review, we will compare miR oligonucleotides, mimics and antagomirs as therapeutic reagents to treat disease and regenerate tissues. Newer technology will be discussed as well as the efficiency and efficacy of using these technologies to express or inhibit miRs in treating and repairing oral tissues. Delivery of these molecules using extracellular vesicles and nanoparticles can achieve different results and depending on their composition will elicit specific effects. We will highlight the specificity, toxicity, stability, and effectiveness of several miR systems in regenerative medicine.

  View details for DOI 10.1042/BST20221448

  View details for Web of Science ID 000974458000001

  View details for PubMedID 37073783

• Exploring craniofacial and dental development with microRNAs. Biochemical Society transactions Su, D., Krongbaramee, T., Sun, H., Hong, L., Amendt, B. A. 2022; 50 (6): 1897-1909

  Abstract

  microRNAs (miRs) are small RNA molecules that regulate many cellular and developmental processes. They control gene expression pathways during specific developmental time points and are required for tissue homeostasis and stem cell maintenance. miRs as therapeutic reagents in tissue regeneration and repair hold great promise and new technologies are currently being designed to facilitate their expression or inhibition. Due to the large amount of miR research in cells and cancer many cellular processes and gene networks have been delineated however, their in vivo response can be different in complex tissues and organs. Specifically, this report will discuss animal developmental models to understand the role of miRs as well as xenograft, disease, and injury models. We will discuss the role of miRs in clinical studies including their diagnostic function, as well as their potential ability to correct craniofacial diseases.

  View details for DOI 10.1042/BST20221042

  View details for PubMedID 36484693

• HMGN2 represses gene transcription via interaction with transcription factors Lef-1 and Pitx2 during amelogenesis. The Journal of biological chemistry Eliason, S., Su, D., Pinho, F., Sun, Z., Zhang, Z., Li, X., Sweat, M., Venugopalan, S. R., He, B., Bustin, M., Amendt, B. A. 2022; 298 (9): 102295

  Abstract

  The chromatin-associated high mobility group protein N2 (HMGN2) cofactor regulates transcription factor activity through both chromatin and protein interactions. Hmgn2 expression is known to be developmentally regulated, but the post-transcriptional mechanisms that regulate Hmgn2 expression and its precise roles in tooth development remain unclear. Here, we demonstrate that HMGN2 inhibits the activity of multiple transcription factors as a general mechanism to regulate early development. Bimolecular fluorescence complementation, pull-down, and coimmunoprecipitation assays show that HMGN2 interacts with the transcription factor Lef-1 through its HMG-box domain as well as with other early development transcription factors, Dlx2, FoxJ1, and Pitx2. Furthermore, EMSAs demonstrate that HMGN2 binding to Lef-1 inhibits its DNA-binding activity. We found that Pitx2 and Hmgn2 associate with H4K5ac and H3K4me2 chromatin marks in the proximal Dlx2 promoter, demonstrating Hmgn2 association with open chromatin. In addition, we demonstrate that microRNAs (miRs) mir-23a and miR-23b directly target Hmgn2, promoting transcriptional activation at several gene promoters, including the amelogenin promoter. In vivo, we found that decreased Hmgn2 expression correlates with increased miR-23 expression in craniofacial tissues as the murine embryo develops. Finally, we show that ablation of Hmgn2 in mice results in increased amelogenin expression because of increased Pitx2, Dlx2, Lef-1, and FoxJ1 transcriptional activity. Taken together, our results demonstrate both post-transcriptional regulation of Hmgn2 by miR-23a/b and post-translational regulation of gene expression by Hmgn2-transcription factor interactions. We conclude that HMGN2 regulates tooth development through its interaction with multiple transcription factors.

  View details for DOI 10.1016/j.jbc.2022.102295

  View details for PubMedID 35872015

  View details for PubMedCentralID PMC9418915

• The <i>miR</i>-<i>200</i> family regulates the epithelial stem cell niche during craniofacial and dental development Amendt, B. A., Leonard, R. J., Su, D., Eliason, S. L. WILEY. 2022

  View details for DOI 10.1096/fasebj.2022.36.S1.R4861

  View details for Web of Science ID 000878430605273

• Co-opting <i>Lef</i>-<i>1</i> and <i>miR-26b</i>activities to regulate dental epithelial stem cells and supporting Su, D., Eliason, S., Leonard, R., Shao, F., Amendt, B. WILEY. 2022

  View details for DOI 10.1096/fasebj.2022.36.S1.R4165

  View details for Web of Science ID 000878430604389

• HMGN2 regulates transcription factor activity through chromatin modifications and protein interactions, developmentally modulated by <i>microRNA</i>-<i>23</i> Amendt, B. A., Eliason, S., Su, D. WILEY. 2022

  View details for DOI 10.1096/fasebj.2022.36.S1.R4093

  View details for Web of Science ID 000878430604323

• miR-17 acts as a tumor suppressor by negatively regulating the miR-17-92 cluster. Molecular therapy. Nucleic acids Sweat, Y., Ries, R. J., Sweat, M., Su, D., Shao, F., Eliason, S., Amendt, B. A. 2021; 26: 1148-1158

  Abstract

  Anaplastic thyroid cancer (ATC) is an aggressive, highly metastatic cancer that expresses high levels of the microRNA (miR)-17-92 cluster. We employ an miR inhibitor system to study the function of the different miRs within the miR-17-92 cluster based on seed sequence homology in the ATC SW579 cell line. While three of the four miR-17-92 families were oncogenic, we uncovered a novel role for miR-17 as a tumor suppressor in vitro and in vivo. Surprisingly, miR-17 inhibition increased expression of the miR-17-92 cluster and significantly increased the levels of the miR-18a and miR-19a mature miRs. miR-17 inhibition increased expression of the cell cycle activator CCND2, associated with increased cell proliferation and tumor growth in transplanted SW579 cells in xenograft mice. miR-17 regulates MYCN and c-MYC expression in SW579 cells, and the inhibition of miR-17 increased MYCN and c-MYC expression, which increased pri-miR-17-92 transcripts. Thus, inhibition of miR-17 activated the expression of the oncogenic miRs, miR-18a and miR-19a. While many cancers express high levels of miR-17, linking it with tumorigenesis, we demonstrate that miR-17 inhibition does not inhibit thyroid tumor growth in SW579 and MDA-T32 ATC cells but increases expression of the other miR-17-92 family members and genes to induce cancer progression.

  View details for DOI 10.1016/j.omtn.2021.10.021

  View details for PubMedID 34853714

  View details for PubMedCentralID PMC8601969

• A putative long noncoding RNA-encoded micropeptide maintains cellular homeostasis in pancreatic β cells. Molecular therapy. Nucleic acids Li, M., Shao, F., Qian, Q., Yu, W., Zhang, Z., Chen, B., Su, D., Guo, Y., Phan, A. V., Song, L. S., Stephens, S. B., Sebag, J., Imai, Y., Yang, L., Cao, H. 2021; 26: 307-320

  Abstract

  Micropeptides (microproteins) encoded by transcripts previously annotated as long noncoding RNAs (lncRNAs) are emerging as important mediators of fundamental biological processes in health and disease. Here, we applied two computational tools to identify putative micropeptides encoded by lncRNAs that are expressed in the human pancreas. We experimentally verified one such micropeptide encoded by a β cell- and neural cell-enriched lncRNA TCL1 Upstream Neural Differentiation-Associated RNA (TUNAR, also known as TUNA, HI-LNC78, or LINC00617). We named this highly conserved 48-amino-acid micropeptide beta cell- and neural cell-regulin (BNLN). BNLN contains a single-pass transmembrane domain and localizes at the endoplasmic reticulum (ER) in pancreatic β cells. Overexpression of BNLN lowered ER calcium levels, maintained ER homeostasis, and elevated glucose-stimulated insulin secretion in pancreatic β cells. We further assessed the BNLN expression in islets from mice fed a high-fat diet and a regular diet and found that BNLN is suppressed by diet-induced obesity (DIO). Conversely, overexpression of BNLN enhanced insulin secretion in islets from lean and obese mice as well as from humans. Taken together, our study provides the first evidence that lncRNA-encoded micropeptides play a critical role in pancreatic β cell functions and provides a foundation for future comprehensive analyses of micropeptide function and pathophysiological impact on diabetes.

  View details for DOI 10.1016/j.omtn.2021.06.027

  View details for PubMedID 34513312

  View details for PubMedCentralID PMC8416971

• The miR-200 family is required for ectodermal organ development through the regulation of the epithelial stem cell niche. Stem cells (Dayton, Ohio) Sweat, M., Sweat, Y., Yu, W., Su, D., Leonard, R. J., Eliason, S. L., Amendt, B. A. 2021; 39 (6): 761-775

  Abstract

  The murine lower incisor ectodermal organ contains a single epithelial stem cell (SC) niche that provides epithelial progenitor cells to the continuously growing rodent incisor. The dental stem cell niche gives rise to several cell types and we demonstrate that the miR-200 family regulates these cell fates. The miR-200 family is highly enriched in the differentiated dental epithelium and absent in the stem cell niche. In this study, we inhibited the miR-200 family in developing murine embryos using new technology, resulting in an expanded epithelial stem cell niche and lack of cell differentiation. Inhibition of individual miRs within the miR-200 cluster resulted in differential developmental and cell morphology defects. miR-200 inhibition increased the expression of dental epithelial stem cell markers, expanded the stem cell niche and decreased progenitor cell differentiation. RNA-seq. identified miR-200 regulatory pathways involved in cell differentiation and compartmentalization of the stem cell niche. The miR-200 family regulates signaling pathways required for cell differentiation and cell cycle progression. The inhibition of miR-200 decreased the size of the lower incisor due to increased autophagy and cell death. New miR-200 targets demonstrate gene networks and pathways controlling cell differentiation and maintenance of the stem cell niche. This is the first report demonstrating how the miR-200 family is required for in vivo progenitor cell proliferation and differentiation.

  View details for DOI 10.1002/stem.3342

  View details for PubMedID 33529466

  View details for PubMedCentralID PMC8247948

• Plasmid encoding microRNA-200c ameliorates periodontitis and systemic inflammation in obese mice. Molecular therapy. Nucleic acids Krongbaramee, T., Zhu, M., Qian, Q., Zhang, Z., Eliason, S., Shu, Y., Qian, F., Akkouch, A., Su, D., Amendt, B. A., Yang, L., Hong, L. 2021; 23: 1204-1216

  Abstract

  The present study was conducted to characterize microRNA-200c (miR-200c) and its regulators in adipogenic differentiation, obesity, and periodontitis in obese subjects (PiOSs), and to determine the therapeutic efficacy of plasmid DNA encoding miR-200c as a treatment for PiOSs. We report that highly expressed miR-200c in gingival tissues was downregulated in diet-induced obese (DIO) mice and during adipogenic differentiation of human bone marrow mesenchymal stromal cells (hBMSCs). Local injection of Porphyromonas gingivalis lipopolysaccharide (Pg-LPS) in the maxilla interdental gingiva of DIO mice reduced miR-200c in gingival and adipose tissues and induced periodontal inflammation associated with systemic elevation of interleukin-6 (IL-6) and impaired glucose tolerance. The inhibitory functions of Pg-LPS and IL-6 on miR-200c and their effectiveness on Zeb1 were confirmed in vitro. Injection of naked plasmid DNA encoding miR-200c into the gingiva effectively rescued miR-200c downregulation, prevented periodontal and systemic inflammation, and alleviated the impaired glucose metabolism in obese mice with LPS-induced periodontitis. Increased circulating exosomal miR-200c and its function on suppressing proinflammatory cytokines and adipogenesis explained the mechanism(s) of gingival application of miR-200c in attenuating systemic inflammation in PiOSs. These results demonstrated that miR-200c reduced by Pg-LPS and IL-6 in periodontitis and obesity might lead to the pathogenesis of PiOSs, and upregulation of miR-200c in the gingiva presents a therapeutic approach for PiOSs.

  View details for DOI 10.1016/j.omtn.2021.01.030

  View details for PubMedID 33664998

  View details for PubMedCentralID PMC7899952

• Mushroom lectin overcomes hepatitis B virus tolerance via TLR6 signaling. Scientific reports He, M., Su, D., Liu, Q., Gao, W., Kang, Y. 2017; 7 (1): 5814

  Abstract

  Currently, chronic hepatitis B virus (HBV) infection remains a serious public health problem in the world. Recombinant HBV vaccine, as a preventive strategy against HBV infection, generates high antibody level, but it is not effective to activate innate and cellular immunity for chronic HBV infection therapy. Lectins from mushroom are natural and active proteins which have been shown important biological functions. However, little is known about the immunological mechanism engaged by mushroom lectins. Here we report that, lectin from Pleurotus ostreatus (POL) stimulated innate response by activating Toll-like receptor 6 signal pathway of dendritic cells. Subsequently POL enhanced HBV specific antibody level and follicular helper T cells response which overcame HBV tolerance in transgenic mice. This study suggests a novel mechanism for POL acting on immune response and a therapeutic approach to break HBV tolerance.

  View details for DOI 10.1038/s41598-017-06261-5

  View details for PubMedID 28724955

  View details for PubMedCentralID PMC5517594