scholarly journals Disruption of a hedgehog-foxf1-rspo2 signaling axis leads to tracheomalacia and a loss of sox9+ tracheal chondrocytes

2020 ◽  
pp. dmm.046573
Author(s):  
Talia Nasr ◽  
Andrea M. Holderbaum ◽  
Praneet Chaturvedi ◽  
Kunal Agarwal ◽  
Jessica L. Kinney ◽  
...  
Keyword(s):  
Birth Defect ◽  
Molecular Mechanisms ◽  
Lineage Tracing ◽  
Dramatic Reduction ◽  
Tracheal Cartilage ◽  
Cartilage Development ◽  
Mouse Mutants ◽  
Gli Transcription Factors ◽  
Signaling Axis ◽  
Repressor Activity

Congenital tracheomalacia, resulting from incomplete tracheal cartilage development, is a relatively common birth defect that severely impairs breathing in neonates. Mutations in the Hedgehog (HH) pathway and downstream Gli transcription factors are associated with tracheomalacia in patients and mouse models; however, the underlying molecular mechanisms are unclear. Using multiple HH/Gli mouse mutants including one that mimics Pallister-Hall Syndrome, we show that excessive Gli repressor activity prevents specification of tracheal chondrocytes. Lineage tracing experiments show that Sox9+ chondrocytes arise from HH-responsive splanchnic mesoderm in the fetal foregut that expresses the transcription factor Foxf1. Disrupted HH/Gli signaling results in 1) loss of Foxf1 which in turn is required to support Sox9+ chondrocyte progenitors and 2) a dramatic reduction in Rspo2, a secreted ligand that potentiates Wnt signaling known to be required for chondrogenesis. These results reveal a HH-Foxf1-Rspo2 signaling axis that governs tracheal cartilage development and informs the etiology of tracheomalacia.

scholarly journals Disruption of a Hedgehog-Foxf1-Rspo2 Signaling Axis Leads to Tracheomalacia and a Loss of Sox9+ Tracheal Chondrocytes

2020 ◽  
Author(s):  
Talia Nasr ◽  
Praneet Chaturvedi ◽  
Kunal Agarwal ◽  
Jessica L. Kinney ◽  
Keziah Daniels ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Lineage Tracing ◽  
Tracheal Cartilage ◽  
Cartilage Development ◽  
Mouse Mutants ◽  
Gli Transcription Factors ◽  
Signaling Axis ◽  
Summary Statement ◽  
Mechanistic Basis ◽  
Repressor Activity

ABSTRACTCongenital tracheomalacia, resulting from incomplete tracheal cartilage development, is a relatively common birth defect that severely impairs breathing in neonates. Mutations in the Hedgehog (HH) pathway and downstream Gli transcription factors are associated with tracheomalacia in patients and mouse models; however, the underlying molecular mechanisms are unclear. Using multiple HH/Gli mouse mutants including one that mimics Pallister-Hall Syndrome, we show that excessive Gli repressor activity prevents specification of tracheal chondrocytes. Lineage tracing experiments show that Sox9+ chondrocytes arise from HH-responsive splanchnic mesoderm in the fetal foregut that expresses the transcription factor Foxf1. Disrupted HH/Gli signaling results in 1) loss of Foxf1 which in turn is required to support Sox9+ chondrocyte progenitors and 2) a dramatic reduction in Rspo2, a secreted ligand that potentiates Wnt signaling known to be required for chondrogenesis. These results reveal a HH-Foxf1-Rspo2 signaling axis that governs tracheal cartilage development and informs the etiology of tracheomalacia.SUMMARY STATEMENTThis work provides a mechanistic basis for tracheomalacia in patients with Hedgehog pathway mutations.

scholarly journals A systems biology model of junctional localization and downstream signaling of the Ang–Tie signaling pathway

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Yu Zhang ◽  
Christopher D. Kontos ◽  
Brian H. Annex ◽  
Aleksander S. Popel
Keyword(s):  
Signaling Pathway ◽  
Molecular Mechanisms ◽  
Vascular Dysfunction ◽  
Reaction Network ◽  
Vascular Growth ◽  
Downstream Signaling ◽  
Signaling Axis ◽  
Agonistic Activity ◽  
Molecular Regulatory Mechanisms

AbstractThe Ang–Tie signaling pathway is an important vascular signaling pathway regulating vascular growth and stability. Dysregulation in the pathway is associated with vascular dysfunction and numerous diseases that involve abnormal vascular permeability and endothelial cell inflammation. The understanding of the molecular mechanisms of the Ang–Tie pathway has been limited due to the complex reaction network formed by the ligands, receptors, and molecular regulatory mechanisms. In this study, we developed a mechanistic computational model of the Ang–Tie signaling pathway validated against experimental data. The model captures and reproduces the experimentally observed junctional localization and downstream signaling of the Ang–Tie signaling axis, as well as the time-dependent role of receptor Tie1. The model predicts that Tie1 modulates Tie2’s response to the context-dependent agonist Ang2 by junctional interactions. Furthermore, modulation of Tie1’s junctional localization, inhibition of Tie2 extracellular domain cleavage, and inhibition of VE-PTP are identified as potential molecular strategies for potentiating Ang2’s agonistic activity and rescuing Tie2 signaling in inflammatory endothelial cells.

scholarly journals Deficiency of the onco-miRNA cluster, miR-106b∼25, causes oligozoospermia and the cooperative action of miR-106b∼25 and miR-17∼92 is required to maintain male fertility

2020 ◽  
Vol 26 (6) ◽  
pp. 389-401
Author(s):  
Alicia Hurtado ◽  
Rogelio Palomino ◽  
Ina Georg ◽  
Miguel Lao ◽  
Francisca M Real ◽  
...  
Keyword(s):  
Male Fertility ◽  
Molecular Mechanisms ◽  
Mirna Cluster ◽  
Knock Out ◽  
Cooperative Action ◽  
Mouse Mutants ◽  
New Genes ◽  
Mirna Clusters ◽  
Testicular Histology ◽  
And Function

Abstract The identification of new genes involved in sexual development and gonadal function as potential candidates causing male infertility is important for both diagnostic and therapeutic purposes. Deficiency of the onco-miRNA cluster miR-17∼92 has been shown to disrupt spermatogenesis, whereas mutations in its paralog cluster, miR-106b∼25, that is expressed in the same cells, were reported to have no effect on testis development and function. The aim of this work is to determine the role of these two miRNA clusters in spermatogenesis and male fertility. For this, we analyzed miR-106b∼25 and miR-17∼92 single and double mouse mutants and compared them to control mice. We found that miR-106b∼25 knock out testes show reduced size, oligozoospermia and altered spermatogenesis. Transcriptomic analysis showed that multiple molecular pathways are deregulated in these mutant testes. Nevertheless, mutant males conserved normal fertility even when early spermatogenesis and other functions were disrupted. In contrast, miR-17∼92+/−; miR-106b∼25−/− double mutants showed severely disrupted testicular histology and significantly reduced fertility. Our results indicate that miR-106b∼25 and miR-17∼92 ensure accurate gene expression levels in the adult testis, keeping them within the required thresholds. They play a crucial role in testis homeostasis and are required to maintain male fertility. Hence, we have identified new candidate genetic factors to be screened in the molecular diagnosis of human males with reproductive disorders. Finally, considering the well-known oncogenic nature of these two clusters and the fact that patients with reduced fertility are more prone to testicular cancer, our results might also help to elucidate the molecular mechanisms linking both pathologies.

Abstract 061: Cell Fate Changes During Tubular Damage and Regeneration in the Mouse Kidney

Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Vidya K Nagalakshmi ◽  
Minghong Li ◽  
R. A Gomez ◽  
Maria Luisa S Sequeira-Lopez
Keyword(s):  
Cell Fate ◽  
Ureteral Obstruction ◽  
Molecular Mechanisms ◽  
Interstitial Fibrosis ◽  
Kidney Diseases ◽  
Collecting Duct ◽  
Lineage Tracing ◽  
Tubular Damage ◽  
Renal Tubules ◽  
Atubular Glomeruli

Tubular degeneration, loss of renal tubules and interstitial fibrosis due to kidney injury lead to chronic renal disease and hypertension. Using a partial unilateral ureteral obstruction (pUUO) model in neonatal mice, we analyzed the fate cell changes that occur during obstruction and during recovery following the release of UUO. We traced the fate of cells derived from the renal stroma, cap mesenchyme and ureteric bud epithelium using Foxd1-Cre, Six2-Cre and HoxB7-Cre mice respectively, crossed with double fluorescent reporter (mT/mG) mice. pUUO was performed 24-36h after birth (n=84). In a group of pups (n=37), the obstruction was released after seven days. Sham operated animals (n=35) were used as controls. Lineage tracing revealed that Foxd1-derived interstitial pericytes acquired α-smooth muscle actin expression and underwent significant expansion due to pUUO (fibrotic area 91.06+/-6.77 %). Release of obstruction resulted in complete resolution of fibrotic areas (0.00%; p<0.005). Further, loss of Six2-derived cells at the glomerular-tubular junction in pUUO kidneys resulted in the formation of atubular glomeruli (39%). Atubular glomeruli were not observed after release. In addition, a significant loss of HoxB7-derived collecting duct tubules was observed during pUUO. Most collecting ducts recovered following release. Our study indicates that obstruction leads to significant tubular damage, expansion of interstitial pericytes, fibrosis, tubular loss and formation of atubular glomeruli. The striking recovery observed after release of ureteral obstruction suggests a reversal of cell fate changes and tubular regeneration. Elucidation of the cellular and molecular mechanisms mediating these events may be of use in the design of strategies for the prevention and/or treatment of kidney diseases and secondary hypertension.

scholarly journals Cellular and Molecular Mechanisms Underlying Prostate Cancer Development: Therapeutic Implications

Medicines ◽  
2019 ◽  
Vol 6 (3) ◽  
pp. 82 ◽  
Author(s):  
Ugo Testa ◽  
Germana Castelli ◽  
Elvira Pelosi
Keyword(s):  
Prostate Cancer ◽  
Molecular Mechanisms ◽  
Intraepithelial Neoplasia ◽  
Cancer Development ◽  
Initial Development ◽  
Therapeutic Implications ◽  
Cancer Pathways ◽  
Signaling Axis ◽  
Prostate Cancer Development ◽  
Prostate Cancers

Prostate cancer is the most frequent nonskin cancer and second most common cause of cancer-related deaths in man. Prostate cancer is a clinically heterogeneous disease with many patients exhibiting an aggressive disease with progression, metastasis, and other patients showing an indolent disease with low tendency to progression. Three stages of development of human prostate tumors have been identified: intraepithelial neoplasia, adenocarcinoma androgen-dependent, and adenocarcinoma androgen-independent or castration-resistant. Advances in molecular technologies have provided a very rapid progress in our understanding of the genomic events responsible for the initial development and progression of prostate cancer. These studies have shown that prostate cancer genome displays a relatively low mutation rate compared with other cancers and few chromosomal loss or gains. The ensemble of these molecular studies has led to suggest the existence of two main molecular groups of prostate cancers: one characterized by the presence of ERG rearrangements (~50% of prostate cancers harbor recurrent gene fusions involving ETS transcription factors, fusing the 5′ untranslated region of the androgen-regulated gene TMPRSS2 to nearly the coding sequence of the ETS family transcription factor ERG) and features of chemoplexy (complex gene rearrangements developing from a coordinated and simultaneous molecular event), and a second one characterized by the absence of ERG rearrangements and by the frequent mutations in the E3 ubiquitin ligase adapter SPOP and/or deletion of CDH1, a chromatin remodeling factor, and interchromosomal rearrangements and SPOP mutations are early events during prostate cancer development. During disease progression, genomic and epigenomic abnormalities accrued and converged on prostate cancer pathways, leading to a highly heterogeneous transcriptomic landscape, characterized by a hyperactive androgen receptor signaling axis.

scholarly journals Single-cell RNA-seq analysis revealed long-lasting adverse effects of tamoxifen on neurogenesis in prenatal and adult brains

2020 ◽  
Vol 117 (32) ◽  
pp. 19578-19589 ◽  
Author(s):  
Chia-Ming Lee ◽  
Liqiang Zhou ◽  
Jiping Liu ◽  
Jiayu Shi ◽  
Yanan Geng ◽  
...  
Keyword(s):  
Adverse Effects ◽  
Single Cell ◽  
Molecular Mechanisms ◽  
Genetic Manipulation ◽  
Lineage Tracing ◽  
In Vitro Assays ◽  
Fetal Mortality ◽  
Neural Lineage ◽  
Cortical Neurogenesis

The CreER/LoxP system is widely accepted to track neural lineages and study gene functions upon tamoxifen (TAM) administration. We have observed that prenatal TAM treatment caused high rates of delayed delivery and fetal mortality. This substance could produce undesired results, leading to data misinterpretation. Here, we report that administration of TAM during early stages of cortical neurogenesis promoted precocious neural differentiation, while it inhibited neural progenitor cell (NPC) proliferation. The TAM-induced inhibition of NPC proliferation led to deficits in cortical neurogenesis, dendritic morphogenesis, synaptic formation, and cortical patterning in neonatal and postnatal offspring. Mechanistically, by employing single-cell RNA-sequencing (scRNA-seq) analysis combined with in vivo and in vitro assays, we show TAM could exert these drastic effects mainly through dysregulating the Wnt-Dmrta2 signaling pathway. In adult mice, administration of TAM significantly attenuated NPC proliferation in both the subventricular zone and the dentate gyrus. This study revealed the cellular and molecular mechanisms for the adverse effects of TAM on corticogenesis, suggesting that care must be taken when using the TAM-induced CreER/LoxP system for neural lineage tracing and genetic manipulation studies in both embryonic and adult brains.

scholarly journals Perivascular-Derived Mesenchymal Stem Cells

2019 ◽  
Vol 98 (10) ◽  
pp. 1066-1072 ◽  
Author(s):  
V. Yianni ◽  
P.T. Sharpe
Keyword(s):  
Tissue Engineering ◽  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Dental Pulp ◽  
Molecular Mechanisms ◽  
Lineage Tracing ◽  
Specific Gene ◽  
Genetic Lineage ◽  
Differentiation Potential

Cells have been identified in postnatal tissues that, when isolated from multiple mesenchymal compartments, can be stimulated in vitro to give rise to cells that resemble mature mesenchymal phenotypes, such as odontoblasts, osteoblasts, adipocytes, and myoblasts. This has made these adult cells, collectively called mesenchymal stem cells (MSCs), strong candidates for fields such as tissue engineering and regenerative medicine. Based on evidence from in vivo genetic lineage–tracing studies, pericytes have been identified as a source of MSC precursors in vivo in multiple organs, in response to injury or during homeostasis. Questions of intense debate and interest in the field of tissue engineering and regenerative studies include the following: 1) Are all pericytes, irrespective of tissue of isolation, equal in their differentiation potential? 2) What are the mechanisms that regulate the differentiation of MSCs? To gain a better understanding of the latter, recent work has utilized ChIP-seq (chromatin immunoprecipitation followed by sequencing) to reconstruct histone landscapes. This indicated that for dental pulp pericytes, the odontoblast-specific gene Dspp was found in a transcriptionally permissive state, while in bone marrow pericytes, the osteoblast-specific gene Runx2 was primed for expression. RNA sequencing has also been utilized to further characterize the 2 pericyte populations, and results highlighted that dental pulp pericytes are already precommitted to an odontoblast fate based on enrichment analysis indicating overrepresentation of key odontogenic genes. Furthermore, ChIP-seq analysis of the polycomb repressive complex 1 component RING1B indicated that this complex is likely to be involved in inhibiting inappropriate differentiation, as it localized to a number of loci of key transcription factors that are needed for the induction of adipogenesis, chondrogenesis, or myogenesis. In this review, we highlight recent data elucidating molecular mechanisms that indicate that pericytes can be tissue-specific precommitted MSC precursors in vivo and that this precommitment is a major driving force behind MSC differentiation.

scholarly journals Mutations in long-lived epithelial stem cells and their clonal progeny in pre-malignant lesions and in oral squamous cell carcinoma

2020 ◽  
Vol 41 (11) ◽  
pp. 1553-1564
Author(s):  
Marta Melis ◽  
Tuo Zhang ◽  
Theresa Scognamiglio ◽  
Lorraine J Gudas
Keyword(s):  
Stem Cells ◽  
Cell Adhesion ◽  
Squamous Cell ◽  
Planar Cell Polarity ◽  
Molecular Mechanisms ◽  
Growth Factor Receptor ◽  
Lineage Tracing ◽  
Epithelial Stem Cells ◽  
Single Nucleotide Variants ◽  
Phosphoinositide 3 Kinase

Abstract Oral squamous cell carcinomas (OSCCs) are the most common cancers of the oral cavity, but the molecular mechanisms driving OSCC carcinogenesis remain unclear. Our group previously established a murine OSCC model based on a 10-week carcinogen [4-nitroquinoline 1-oxide (4-NQO)] treatment. Here we used K14CreERTAM;Rosa26LacZ mice to perform lineage tracing to delineate the mutational profiles in clonal cell populations resulting from single, long-lived epithelial stem cells, here called LacZ+ stem cell clones (LSCCs). Using laser-capture microdissection, we examined mutational changes in LSCCs immediately after the 10-week 4-NQO treatment and &gt;17 weeks after 4-NQO treatment. We found a 1.8-fold ±0.4 (P = 0.009) increase in single-nucleotide variants and insertions/deletions (indels) in tumor compared with pre-neoplastic LSCCs. The percentages of indels and of loss of heterozygosity events were 1.3-fold±0.3 (P = 0.02) and 2.2-fold±0.7 (P = 0.08) higher in pre-neoplastic compared with tumor LSCCs. Mutations in cell adhesion- and development-associated genes occurred in 83% of the tumor LSCCs. Frequently mutated genes in tumor LSCCs were involved in planar cell polarity (Celsr1, Fat4) or development (Notch1). Chromosomal amplifications in 50% of the tumor LSCCs occurred in epidermal growth factor receptor, phosphoinositide 3-kinase and cell adhesion pathways. All pre-neoplastic and tumor LSCCs were characterized by key smoking-associated changes also observed in human OSCC, C&gt;A and G&gt;T. DeconstructSigs analysis identified smoking and head and neck cancer as the most frequent mutational signatures in pre-neoplastic and tumor LSCCs. Thus, this model recapitulates a smoking-associated mutational profile also observed in humans and illustrates the role of LSCCs in early carcinogenesis and OSCCs.

scholarly journals Regulation of melanoma malignancy by the RP11-705C15.3/miR-145-5p/NRAS/MAPK signaling axis

2020 ◽  
Author(s):  
Xiang-jun Chen ◽  
Sha Liu ◽  
Dong-mei Han ◽  
De-zhi Han ◽  
Wei-jing Sun ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Melanoma Cell ◽  
Molecular Mechanisms ◽  
Ectopic Expression ◽  
Therapeutic Targets ◽  
Mapk Signaling ◽  
Migration And Invasion ◽  
Functional Assays ◽  
Melanoma Cell Proliferation ◽  
Signaling Axis

AbstractMelanoma is a common lethal skin cancer. Dissecting molecular mechanisms driving the malignancy of melanoma may uncover potential therapeutic targets. We previously identified miR-145-5p as an important tumor-suppressive microRNA in melanoma. Here, we further investigated the roles of long non-coding RNAs (lncRNAs) in melanoma. We identified RP11-705C15.3, a regulator of miR-145-5p, as an oncogenic lncRNA in melanoma. RP11-705C15.3 competitively bound miR-145-5p, relieved the repressive roles of miR-145-5p on its target NRAS, upregulated NRAS expression, and activated MAPK signaling. In vitro functional assays revealed that ectopic expression of RP11-705C15.3 promoted melanoma cell proliferation, inhibited apoptosis, and promoted migration and invasion. Silencing of RP11-705C15.3 repressed melanoma cell proliferation, induced apoptosis, and repressed migration and invasion. Notably, the roles of RP11-705C15.3 in melanoma cell proliferation, apoptosis, migration and invasion are reversed by miR-145-5p overexpression. In vivo functional assays revealed that RP11-705C15.3 promoted melanoma tumor growth and metastasis, which were also reversed by miR-145-5p overexpression. Furthermore, we investigated the expression of RP11-705C15.3 in clinical melanoma tissues and found that RP11-705C15.3 was increased in melanoma tissues. High expression of RP11-705C15.3 was positively correlated with thickness, ulceration, metastasis, and inferior overall survival. Taken together, our findings suggest RP11-705C15.3 as a novel oncogene in melanoma, and highlight that the RP11-705C15.3/miR-145-5p/NRAS/MAPK signaling axis may be potential therapeutic targets for melanoma.

scholarly journals The multi-faceted functioning portrait of LRF/ZBTB7A

2019 ◽  
Vol 13 (1) ◽  
Author(s):  
Caterina Constantinou ◽  
Magda Spella ◽  
Vasiliki Chondrou ◽  
George P. Patrinos ◽  
Adamantia Papachatzopoulou ◽  
...  
Keyword(s):  
Cell Fate ◽  
Cellular Response ◽  
Molecular Mechanisms ◽  
Aerobic Glycolysis ◽  
Specific Cell ◽  
Regulation Of Transcription ◽  
Cancer Type ◽  
Cellular Effects ◽  
Physiological Processes ◽  
Signaling Axis

AbstractTranscription factors (TFs) consisting of zinc fingers combined with BTB (for broad-complex, tram-track, and bric-a-brac) domain (ZBTB) are a highly conserved protein family that comprises a multifunctional and heterogeneous group of TFs, mainly modulating cell developmental events and cell fate. LRF/ZBTB7A, in particular, is reported to be implicated in a wide variety of physiological and cancer-related cell events. These physiological processes include regulation of erythrocyte maturation, B/T cell differentiation, adipogenesis, and thymic insulin expression affecting consequently insulin self-tolerance. In cancer, LRF/ZBTB7A has been reported to act either as oncogenic or as oncosuppressive factor by affecting specific cell processes (proliferation, apoptosis, invasion, migration, metastasis, etc) in opposed ways, depending on cancer type and molecular interactions. The molecular mechanisms via which LRF/ZBTB7A is known to exert either physiological or cancer-related cellular effects include chromatin organization and remodeling, regulation of the Notch signaling axis, cellular response to DNA damage stimulus, epigenetic-dependent regulation of transcription, regulation of the expression and activity of NF-κB and p53, and regulation of aerobic glycolysis and oxidative phosphorylation (Warburg effect). It is a pleiotropic TF, and thus, alterations to its expression status become detrimental for cell survival. This review summarizes its implication in different cellular activities and the commonly invoked molecular mechanisms triggered by LRF/ZBTB7A’s orchestrated action.

Sign in / Sign up

Export Citation Format

Share Document