scholarly journals Distinct roles of Bendless in regulating FSC niche competition and daughter cell differentiation

Development ◽  
2021 ◽  
Vol 148 (22) ◽  
Author(s):  
Sumitra Tatapudy ◽  
Jobelle Peralta ◽  
Todd Nystul
Keyword(s):  
Hedgehog Signaling ◽  
Adult Stem Cells ◽  
Proper Time ◽  
Single Gene ◽  
Multiple Roles ◽  
Cell Fates ◽  
Jnk Pathway ◽  
Jnk Signaling ◽  
Daughter Cells ◽  
Niche Competition

ABSTRACT A major goal in the study of adult stem cells is to understand how cell fates are specified at the proper time and place to facilitate tissue homeostasis. Here, we found that an E2 ubiquitin ligase, Bendless (Ben), has multiple roles in the Drosophila ovarian epithelial follicle stem cell (FSC) lineage. First, Ben is part of the JNK signaling pathway, and we found that it, as well as other JNK pathway genes, are essential for differentiation of FSC daughter cells. Our data suggest that JNK signaling promotes differentiation by suppressing the activation of the EGFR effector, ERK. Also, we found that loss of ben, but not the JNK kinase hemipterous, resulted in an upregulation of hedgehog signaling, increased proliferation and increased niche competition. Lastly, we demonstrate that the hypercompetition phenotype caused by loss of ben is suppressed by decreasing the rate of proliferation or knockdown of the hedgehog pathway effector, Smoothened (Smo). Taken together, our findings reveal a new layer of regulation in which a single gene influences cell signaling at multiple stages of differentiation in the early FSC lineage.

scholarly journals The oxidative stress response regulates DKK1 expression through the JNK signaling cascade in multiple myeloma plasma cells

Blood ◽  
2007 ◽  
Vol 109 (10) ◽  
pp. 4470-4477 ◽  
Author(s):  
Simona Colla ◽  
Fenghuang Zhan ◽  
Wei Xiong ◽  
Xiaosong Wu ◽  
Hongwei Xu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Multiple Myeloma ◽  
Wnt Signaling ◽  
Plasma Cells ◽  
Cell Types ◽  
Signaling Cascade ◽  
Jnk Pathway ◽  
Jnk Signaling ◽  
Dkk1 Expression

Abstract Multiple myeloma (MM) plasma cells, but not those from healthy donors and patients with monoclonal gammopathy of undetermined significance or other plasma cell dyscrasias involving the bone marrow, express the Wnt-signaling antagonist DKK1. We previously reported that secretion of DKK1 by MM cells likely contributes to osteolytic lesions in this disease by inhibiting Wnt signaling, which is essential for osteoblast differentiation and survival. The mechanisms responsible for activation and regulation of DKK1 expression in MM are not known. Herein, we could trace DKK1 expression changes in MM cells to perturbations in the JNK signaling cascade, which is differentially modulated through oxidative stress and interactions between MM cells with osteoclasts in vitro. Despite its role as a tumor suppressor and mediator of apoptosis in other cell types including osteoblasts, our data suggest that DKK1, a stress-responsive gene in MM, does not mediate apoptotic signaling, is not activated by TP53, and its forced overexpression could not inhibit cell growth or sensitize MM cells to apoptosis following treatment with thalidomide or lenalidomide. We conclude that specific strategies to modulate persistent activation of the JNK pathway may be beneficial in preventing disease progression and treating myeloma-associated bone disease by inhibiting DKK1 expression.

scholarly journals Characterization of histone inheritance patterns in the Drosophila female germline

2020 ◽  
Author(s):  
Elizabeth W. Kahney ◽  
Lydia Sohn ◽  
Kayla Viets-Layng ◽  
Robert Johnston ◽  
Xin Chen
Keyword(s):  
Stem Cell ◽  
Cell Fate ◽  
Single Gene ◽  
Asymmetric Division ◽  
Germline Stem Cell ◽  
Inheritance Patterns ◽  
Daughter Cells ◽  
Dividing Cells ◽  
Female Germline

ABSTRACTStem cells have the unique ability to undergo asymmetric division which produces two daughter cells that are genetically identical, but commit to different cell fates. The loss of this balanced asymmetric outcome can lead to many diseases, including cancer and tissue dystrophy. Understanding this tightly regulated process is crucial in developing methods to treat these abnormalities. Here, we report that produced from a Drosophila female germline stem cell asymmetric division, the two daughter cells differentially inherit histones at key genes related to either maintaining the stem cell state or promoting differentiation, but not at constitutively active or silenced genes. We combined histone labeling with DNA Oligopaints to distinguish old versus new histone distribution and visualize their inheritance patterns at single-gene resolution in asymmetrically dividing cells in vivo. This strategy can be widely applied to other biological contexts involving cell fate establishment during development or tissue homeostasis in multicellular organisms.

scholarly journals The JNK Signaling Pathway in Inflammatory Skin Disorders and Cancer

Cells ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 857 ◽  
Author(s):  
Manel Hammouda ◽  
Amy Ford ◽  
Yuan Liu ◽  
Jennifer Zhang
Keyword(s):  
Cell Carcinoma ◽  
Skin Disorders ◽  
Jnk Pathway ◽  
Jnk Signaling ◽  
Cellular Processes ◽  
Downstream Effector ◽  
Wide Range ◽  
Mitogen Activated Protein ◽  
Common Skin ◽  
Apoptosis And Inflammation

The c-Jun N-terminal kinases (JNKs), with its members JNK1, JNK2, and JNK3, is a subfamily of (MAPK) mitogen-activated protein kinases. JNK signaling regulates a wide range of cellular processes, including cell proliferation, differentiation, survival, apoptosis, and inflammation. Dysregulation of JNK pathway is associated with a wide range of immune disorders and cancer. Our objective is to provide a review of JNK proteins and their upstream regulators and downstream effector molecules in common skin disorders, including psoriasis, dermal fibrosis, scleroderma, basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and melanoma.

scholarly journals hCG Improves Luteal Function and Promotes Progesterone Output through the Activation of JNK Pathway in the Luteal Granulosa Cells of the Stimulated IVF Cycles†

2020 ◽  
Vol 102 (6) ◽  
pp. 1270-1280 ◽  
Author(s):  
Gamze Bildik ◽  
Nazli Akin ◽  
Yashar Esmaeilian ◽  
Francesko Hela ◽  
Kayhan Yakin ◽  
...  
Keyword(s):  
Luteinizing Hormone ◽  
Signaling Pathway ◽  
Granulosa Cells ◽  
Luteal Phase ◽  
Steroidogenic Enzymes ◽  
Jnk Pathway ◽  
Jnk Signaling ◽  
Luteal Function ◽  
Jnk Signaling Pathway

Abstract Human chorionic gonadotropin (hCG) is a luteotropic hormone that promotes the survival and steroidogenic activity of corpus luteum (CL) by acting through luteinizing hormone receptors (LHRs) expressed on luteinized theca and granulosa cells (GCs). Therefore, it is used to support luteal phase in in vitro fertilization (IVF) cycles to improve clinical pregnancy rates and prevent miscarriage. However, the molecular mechanism underlying this action of hCG is not well characterized. To address this question, we designed an in vitro translational research study on the luteal GCs obtained from 58 IVF patients. hCG treatment at different concentrations and time points activated c-Jun N-terminal kinase (JNK) pathway and significantly increased its endogenous kinase activity along with upregulated expression of steroidogenic enzymes (steroidogenic acute regulatory protein (stAR), 3β-Hydroxysteroid dehydrogenase (3β-HSD)) in a dose-dependent manner in the luteal GCs. As a result, in vitro P production of the cells was significantly enhanced after hCG. When JNK pathway was inhibited pharmacologically or knocked-down with small interfering RNA luteal function was compromised, P4 production was declined along with the expression of stAR and 3β-HSD in the cells. Further, hCG treatment after JNK inhibition failed to correct the luteal defect and promote P4 output. Similar to hCG, luteinizing hormone (LH) treatment improved luteal function as well and this action of LH was associated with JNK activation in the luteal GCs. These findings could be important from the perspective of CL biology and luteal phase in human because we for the first time identify a critical role for JNK signaling pathway downstream LHR activation by hCG/LH in luteal GCs. Summary Sentence JNK signaling pathway plays a central role in the upregulated expression of the steroidogenic enzymes StAR and 3b-HSD and augmented progesterone production by hCG/LH in human luteal granulosa cells.

scholarly journals The Hippo pathway coactivator Yorkie can reprogram cell fates and create compartment-boundary–like interactions at clone margins

2020 ◽  
Vol 6 (50) ◽  
pp. eabe8159
Author(s):  
Joanna C. D. Bairzin ◽  
Maya Emmons-Bell ◽  
Iswar K. Hariharan
Keyword(s):  
Hedgehog Signaling ◽  
Hippo Pathway ◽  
Activity Levels ◽  
Cell Fates ◽  
Cubitus Interruptus ◽  
Compartment Boundary ◽  
Pathway Activation ◽  
Chromatin Regulator ◽  
Heterotypic Interactions ◽  
The Hippo Pathway

During development, tissue-specific patterns of gene expression are established by transcription factors and then stably maintained via epigenetic mechanisms. Cancer cells often express genes that are inappropriate for that tissue or developmental stage. Here, we show that high activity levels of Yki, the Hippo pathway coactivator that causes overgrowth in Drosophila imaginal discs, can also disrupt cell fates by altering expression of selector genes like engrailed (en) and Ultrabithorax (Ubx). Posterior clones expressing activated Yki can down-regulate en and express an anterior selector gene, cubitus interruptus (ci). The microRNA bantam and the chromatin regulator Taranis both function downstream of Yki in promoting ci expression. The boundary between Yki-expressing posterior clones and surrounding wild-type cells acquires properties reminiscent of the anteroposterior compartment boundary; Hedgehog signaling pathway activation results in production of Dpp. Thus, at least in principle, heterotypic interactions between Yki-expressing cells and their neighbors could activate boundary-specific signaling mechanisms.

scholarly journals The N-Acetylglucosaminidase LytB of Streptococcus pneumoniae Is Involved in the Structure and Formation of Biofilms

2020 ◽  
Vol 86 (10) ◽  
Author(s):  
Mirian Domenech ◽  
Ernesto García
Keyword(s):  
Streptococcus Pneumoniae ◽  
Biofilm Formation ◽  
Single Gene ◽  
Extracellular Polysaccharide ◽  
Extracellular Dna ◽  
Nasopharyngeal Colonization ◽  
Content Type ◽  
Daughter Cells ◽  
Biofilm Matrix

ABSTRACT The N-acetylglucosaminidase LytB of Streptococcus pneumoniae is involved in nasopharyngeal colonization and is responsible for cell separation at the end of cell division; thus, ΔlytB mutants form long chains of cells. This paper reports the construction and properties of a defective pneumococcal mutant producing an inactive LytB protein (LytBE585A). It is shown that an enzymatically active LytB is required for in vitro biofilm formation, as lytB mutants (either ΔlytB or producing the inactive LytBE585A) are incapable of forming substantial biofilms, despite that extracellular DNA is present in the biofilm matrix. Adding small amounts (0.5 to 2.0 μg/ml) of exogenous LytB or some LytB constructs restored the biofilm-forming capacity of lytB mutants to wild-type levels. The LytBE585A mutant formed biofilm more rapidly than ΔlytB mutants in the presence of LytB. This suggests that the mutant protein acted in a structural role, likely through the formation of complexes with extracellular DNA. The chain-dispersing capacity of LytB allowed the separation of daughter cells, presumably facilitating the formation of microcolonies and, finally, of biofilms. A role for the possible involvement of LytB in the synthesis of the extracellular polysaccharide component of the biofilm matrix is also discussed. IMPORTANCE It has been previously accepted that biofilm formation in S. pneumoniae must be a multigenic trait because the mutation of a single gene has led to only to partial inhibition of biofilm production. In the present study, however, evidence that the N-acetylglucosaminidase LytB is crucial in biofilm formation is provided. Despite the presence of extracellular DNA, strains either deficient in LytB or producing a defective LytB enzyme formed only shallow biofilms.

scholarly journals Role of the Hedgehog Signaling Pathway in Regulating the Behavior of Germline Stem Cells

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Shiqin Li ◽  
Meng Wang ◽  
Yanghui Chen ◽  
Wei Wang ◽  
Junying Wu ◽  
...  
Keyword(s):  
Stem Cells ◽  
Signaling Pathway ◽  
Hedgehog Signaling ◽  
Adult Stem Cells ◽  
Reproductive Function ◽  
Future Research ◽  
Germline Stem Cells ◽  
Proliferation And Differentiation ◽  
Hh Signaling

Germline stem cells (GSCs) are adult stem cells that are responsible for the production of gametes and include spermatogonial stem cells (SSCs) and ovarian germline stem cells (OGSCs). GSCs are located in a specialized microenvironment in the gonads called the niche. Many recent studies have demonstrated that multiple signals in the niche jointly regulate the proliferation and differentiation of GSCs, which is of significance for reproductive function. Previous studies have demonstrated that the hedgehog (Hh) signaling pathway participates in the proliferation and differentiation of various stem cells, including GSCs in Drosophila and male mammals. Furthermore, the discovery of mammalian OGSCs challenged the traditional opinion that the number of primary follicles is fixed in postnatal mammals, which is of significance for the reproductive ability of female mammals and the treatment of diseases related to germ cells. Meanwhile, it still remains to be determined whether the Hh signaling pathway participates in the regulation of the behavior of OGSCs. Herein, we review the current research on the role of the Hh signaling pathway in mediating the behavior of GSCs. In addition, some suggestions for future research are proposed.

Effect of pharmacologic inhibition of c-Jun N-terminal kinase (JNK) signaling pathway on cell proliferation and cell cycle progression in human granulosa cell tumor.

2013 ◽  
Vol 31 (15_suppl) ◽  
pp. e22004-e22004
Author(s):  
Ozgur Oktem ◽  
Meltem Muftuoglu ◽  
Filiz Senbabaoglu ◽  
Bulent Urman
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Signaling Pathway ◽  
Granulosa Cell ◽  
Dependent Manner ◽  
Jnk Pathway ◽  
Jnk Signaling ◽  
Curative Therapy ◽  
Jnk Signaling Pathway ◽  
Dose Dependent

e22004 Background: No data are available regarding the signaling pathways that controls the proliferation of granulosa cell tumors (GCT). Preliminary findings showing the activation of c-Jun N-terminal kinase (JNK) signaling pathway in the proliferating granulosa cells has led us to investigate the role of this pathway in human GCT. Methods: Human GCT line COV 434 was used. Cell proliferation was monitored real-time quantitatively for 120h using an impedance-based system. Two different pharmacologic JNK inhibitors SP600125 and AS601245 were used. Their inhibitory concentrations were determined in western blot. Cell cycle was analyzed with flow cytometry and apoptosis with yo-pro-1 staining. Results: First, the growth characteristics of this cell line was delineated (Table 1A). Then the cells were treated with the inhibitors at the indicated doses during the log phase. Their proliferation was significantly halted in a dose-dependent manner by both inhibitors (Table 1B). Furthermore, the cells failed to complete mitosis, and began to accumulate at G2 in a dose dependent manner when JNK pathway was interrupted with AS601245 (59%) and SP600125 (39%) during G2/M transition compared to control cells (7%) proceeding through G2/M phase regularly (p<0.001). Compared to 3.5% of control cells, 14% and 30% of the cells underwent apoptosis when treated with 50 µM SP600125 and AS601245, respectively. At 100 µM, the apoptotic fraction increased to 68% and 76%, respectively (p<0.01). Conclusions: These results suggest that pharmacologic manipulation of JNK pathway may provide a therapeutic benefit in the treatment of GCT for which currently, no curative therapy exists beyond surgery. Funded by a Grant to Ozgur Oktem (TUBITAK109S164). [Table: see text]

scholarly journals Multiple roles for Hedgehog signaling in zebrafish pituitary development

2003 ◽  
Vol 254 (1) ◽  
pp. 19-35 ◽  
Author(s):  
Jennifer L Sbrogna ◽  
Michael J.F Barresi ◽  
Rolf O Karlstrom
Keyword(s):  
Hedgehog Signaling ◽  
Multiple Roles ◽  
Pituitary Development

scholarly journals Injury-stimulated Hedgehog signaling promotes regenerative proliferation of Drosophila intestinal stem cells

2015 ◽  
Vol 208 (6) ◽  
pp. 807-819 ◽  
Author(s):  
Aiguo Tian ◽  
Qing Shi ◽  
Alice Jiang ◽  
Shuangxi Li ◽  
Bing Wang ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Hedgehog Signaling ◽  
Intestinal Stem Cells ◽  
Homeostatic Proliferation ◽  
Jnk Pathway ◽  
Signaling Axis ◽  
Resident Stem Cells ◽  
Hh Signaling ◽  
Stat Pathway

Many adult tissues are maintained by resident stem cells that elevate their proliferation in response to injury. The regulatory mechanisms underlying regenerative proliferation are still poorly understood. Here we show that injury induces Hedgehog (Hh) signaling in enteroblasts (EBs) to promote intestinal stem cell (ISC) proliferation in Drosophila melanogaster adult midgut. Elevated Hh signaling by patched (ptc) mutations drove ISC proliferation noncell autonomously. Inhibition of Hh signaling in the ISC lineage compromised injury-induced ISC proliferation but had little if any effect on homeostatic proliferation. Hh signaling acted in EBs to regulate the production of Upd2, which activated the JAK–STAT pathway to promote ISC proliferation. Furthermore, we show that Hh signaling is stimulated by DSS through the JNK pathway and that inhibition of Hh signaling in EBs prevented DSS-stimulated ISC proliferation. Hence, our study uncovers a JNK–Hh–JAK–STAT signaling axis in the regulation of regenerative stem cell proliferation.

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