scholarly journals Mice lacking JunB are osteopenic due to cell-autonomous osteoblast and osteoclast defects

2004 ◽  
Vol 164 (4) ◽  
pp. 613-623 ◽  
Author(s):  
Lukas Kenner ◽  
Astrid Hoebertz ◽  
F. Timo Beil ◽  
Niamh Keon ◽  
Florian Karreth ◽  
...  
Keyword(s):  
Myeloid Leukemia ◽  
Osteoblast Differentiation ◽  
Essential Gene ◽  
Bone Sialoprotein ◽  
Negative Regulator ◽  
Autonomous Function ◽  
A Cell ◽  
Osteoblast Markers

Because JunB is an essential gene for placentation, it was conditionally deleted in the embryo proper. JunBΔ/Δ mice are born viable, but develop severe low turnover osteopenia caused by apparent cell-autonomous osteoblast and osteoclast defects before a chronic myeloid leukemia-like disease. Although JunB was reported to be a negative regulator of cell proliferation, junBΔ/Δ osteoclast precursors and osteoblasts show reduced proliferation along with a differentiation defect in vivo and in vitro. Mutant osteoblasts express elevated p16INK4a levels, but exhibit decreased cyclin D1 and cyclin A expression. Runx2 is transiently increased during osteoblast differentiation in vitro, whereas mature osteoblast markers such as osteocalcin and bone sialoprotein are strongly reduced. To support a cell-autonomous function of JunB in osteoclasts, junB was inactivated specifically in the macrophage–osteoclast lineage. Mutant mice develop an osteopetrosis-like phenotype with increased bone mass and reduced numbers of osteoclasts. Thus, these data reveal a novel function of JunB as a positive regulator controlling primarily osteoblast as well as osteoclast activity.

scholarly journals SMPDL3B Predicts Poor Prognosis and Contributes to Development of Acute Myeloid Leukemia

2021 ◽  
Vol 8 ◽  
Author(s):  
Huiqing Qu ◽  
Ye Zhu
Keyword(s):  
Overall Survival ◽  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Human Cancer ◽  
Negative Regulator ◽  
Poor Overall Survival ◽  
Clinicopathologic Characteristics ◽  
Acute Myeloid

Background: Acute myeloid leukemia (AML), characterized by the low cure rate and high relapse, urgently needs novel diagnostic or prognostic biomarkers and potential therapeutic targets. Sphingomyelin Phosphodiesterase Acid Like 3B (SMPDL3B) is a negative regulator of Toll-like receptor signaling that plays important roles in the interface of membrane biology and innate immunity. However, the potential role of SMPDL3B in human cancer, especially in AML, is still unknown.Methods: The expression of SMPDL3B in AML samples was investigated through data collected from Gene Expression Omnibus (GEO). Association between SMPDL3B expression and clinicopathologic characteristics was analyzed with the chi-square test. Survival curves were calculated by the Kaplan–Meier method. Cox univariate and multivariate analyses were used to detect risk factors for overall survival. The biological functions of SMPDL3B in human AML were investigated both in vitro and in vivo.Results: Expression of SMPDL3B mRNA was significantly upregulated in human AML samples and closely correlated to cytogenetics risk and karyotypes. Elevated expression of SMPDL3B was associated with poor overall survival and emerged as an independent predictor for poor overall survival in human AML. Blocked SMPDL3B expression inhibited AML cells growth both in vitro and in vivo via promoting cell apoptosis.Conclusion: Taken together, our results demonstrate that SMPDL3B could be used as an efficient prognostic biomarker and represent a potential therapeutic target for human AML.

scholarly journals ZNF191 Inhibits Hepatocellular Carcinoma Metastasis via DLG1-mediated YAP1 Inactivation

2015 ◽  
Author(s):  
Di Wu ◽  
Guoyuan Liu ◽  
Songmin Jiang ◽  
Long Yu
Keyword(s):  
Hepatocellular Carcinoma ◽  
Zinc Finger Protein ◽  
Negative Regulator ◽  
Metastasis Suppressor ◽  
Discs Large ◽  
Chromatin Immunoprecipitation Sequencing ◽  
A Cell ◽  
Carcinoma Metastasis

Searching targets for hepatocellular carcinoma (HCC) treatment, we identified zinc finger protein 191 (ZNF191) as a suppressor against HCC metastasis. Over-expressing ZNF191 in HCC cells impaired cell motility, while ZNF191 depletion promoted HCC cell migration in vitro and metastasis in vivo through triggering yes-associated protein 1 (YAP1) signaling. Chromatin immunoprecipitation-sequencing (ChIP-seq) revealed that ZNF191 specifically bound to the promoter of Discs, Large homolog 1 (DLG1), a cell polarity maintainer and a negative regulator of YAP1. Double-knockdown experiments showed that DLG1 was not only the mediator of ZNF191 s function to suppress migration but also a link between ZNF191 and YAP1 signaling. ZNF191 was down-regulated in metastatic HCCs, correlating positively with DLG1 levels and inversely with YAP1 activation. Our findings indicate ZNF191 functions as a metastasis suppressor via DLG1-mediated YAP1 signaling inactivation.

scholarly journals LncRNA ODIR1 inhibits osteogenic differentiation of hUC-MSCs through the FBXO25/H2BK120ub/H3K4me3/OSX axis

2019 ◽  
Vol 10 (12) ◽  
Author(s):  
Shiwei He ◽  
Sheng Yang ◽  
Yanru Zhang ◽  
Xiaoling Li ◽  
Dan Gao ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Osteogenic Differentiation ◽  
Negative Regulator ◽  
Human Umbilical Cord ◽  
Cullin 3 ◽  
F Box Protein ◽  
Osteoblast Markers

AbstractLong noncoding RNAs (lncRNAs) have been demonstrated to be important regulators during the osteogenic differentiation of mesenchymal stem cells (MSCs). We analyzed the lncRNA expression profile during osteogenic differentiation of human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) and identified a significantly downregulated lncRNA RP11-527N22.2, named osteogenic differentiation inhibitory lncRNA 1, ODIR1. In hUC-MSCs, ODIR1 knockdown significantly promoted osteogenic differentiation, whereas overexpression inhibited osteogenic differentiation in vitro and in vivo. Mechanistically, ODIR1 interacts with F-box protein 25 (FBXO25) and facilitates the proteasome-dependent degradation of FBXO25 by recruiting Cullin 3 (CUL3). FBXO25 increases the mono-ubiquitination of H2BK120 (H2BK120ub) which subsequently promotes the trimethylation of H3K4 (H3K4me3). Both H2BK120ub and H3K4me3 form a loose chromatin structure, inducing the transcription of the key transcription factor osterix (OSX) and increasing the expression of the downstream osteoblast markers, osteocalcin (OCN), osteopontin (OPN), and alkaline phosphatase (ALP). In summary, ODIR1 acts as a key negative regulator during the osteogenic differentiation of hUC-MSCs through the FBXO25/H2BK120ub/H3K4me3/OSX axis, which may provide a novel understanding of lncRNAs that regulate the osteogenesis of MSCs and a potential therapeutic strategy for the regeneration of bone defects.

Members of the microRNA-17-92 cluster exhibit a cell-intrinsic antiangiogenic function in endothelial cells

Blood ◽  
2010 ◽  
Vol 115 (23) ◽  
pp. 4944-4950 ◽  
Author(s):  
Carmen Doebele ◽  
Angelika Bonauer ◽  
Ariane Fischer ◽  
Alexander Scholz ◽  
Yvonne Reiss ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Tumor Angiogenesis ◽  
Janus Kinase ◽  
Negative Regulator ◽  
3 Dimensional ◽  
Small Noncoding Rnas ◽  
A Cell ◽  
Sprout Formation

Abstract MicroRNAs are endogenously expressed small noncoding RNAs that regulate gene expression on the posttranscriptional level. The miR-17-92 cluster (encoding miR-17, -18a, -19a/b, -20a, and miR-92a) is highly expressed in tumor cells and is up-regulated by ischemia. Whereas miR-92a was recently identified as negative regulator of angiogenesis, the specific functions of the other members of the cluster are less clear. Here we demonstrate that overexpression of miR-17, -18a, -19a, and -20a significantly inhibited 3-dimensional spheroid sprouting in vitro, whereas inhibition of miR-17, -18a, and -20a augmented endothelial cell sprout formation. Inhibition of miR-17 and miR-20a in vivo using antagomirs significantly increased the number of perfused vessels in Matrigel plugs, whereas antagomirs that specifically target miR-18a and miR-19a were less effective. However, systemic inhibition of miR-17/20 did not affect tumor angiogenesis. Further mechanistic studies showed that miR-17/20 targets several proangiogenic genes. Specifically, Janus kinase 1 was shown to be a direct target of miR-17. In summary, we show that miR-17/20 exhibit a cell-intrinsic antiangiogenic activity in endothelial cells. Inhibition of miR-17/20 specifically augmented neovascularization of Matrigel plugs but did not affect tumor angiogenesis indicating a context-dependent regulation of angiogenesis by miR-17/20 in vivo.

Phosphatase Wip1 negatively regulates neutrophil development through p38 MAPK-STAT1

Blood ◽  
2013 ◽  
Vol 121 (3) ◽  
pp. 519-529 ◽  
Author(s):  
Guangwei Liu ◽  
Xuelian Hu ◽  
Bo Sun ◽  
Tao Yang ◽  
Jianfeng Shi ◽  
...  
Keyword(s):  
P38 Mapk ◽  
Molecular Mechanisms ◽  
Negative Regulator ◽  
Cell Type ◽  
A Cell ◽  
Cell Type Specific ◽  
Neutrophil Differentiation ◽  
Deficient Mice

Abstract Neutrophils are critically involved in host defense and tissue damage. Intrinsic molecular mechanisms controlling neutrophil differentiation and activities are poorly defined. Herein we found that p53-induced phosphatase 1(Wip1) is preferentially expressed in neutrophils among immune cells. The Wip1 expression is gradually up-regulated during the differentiation of myeloid precursors into mature neutrophils. Wip1-deficient mice and chimera mice with Wip1−/− hematopoietic cells had an expanded pool of neutrophils with hypermature phenotypes in the periphery. The in vivo and in vitro studies showed that Wip1 deficiency mainly impaired the developing process of myeloid progenitors to neutrophils in an intrinsic manner. Mechanism studies showed that the enhanced development and maturation of neutrophils caused by Wip1 deficiency were mediated by p38 MAPK-STAT1 but not p53-dependent pathways. Thus, our findings identify a previously unrecognized p53-independent function of Wip1 as a cell type-specific negative regulator of neutrophil generation and homeostasis through limiting the p38 MAPK-STAT1 pathway.

The Proteasome Inhibitor Bortezomib Affects Osteoblastogenesis and Bone Formation In Vitro and In Vivo in Multiple Myeloma Patients.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 508-508 ◽  
Author(s):  
Nicola Giuliani ◽  
Francesca Morandi ◽  
Sara Tagliaferri ◽  
Mirca Lazzaretti ◽  
Sabrina Bonomini ◽  
...  
Keyword(s):  
Bone Formation ◽  
Proteasome Inhibitor ◽  
Osteoblast Differentiation ◽  
Osteoblastic Cells ◽  
Beta Catenin ◽  
Bortezomib Treatment ◽  
And Function ◽  
Osteoblast Markers

Abstract It is well established that osteoblast formation and function are profoundly impaired in multiple myeloma (MM) patients. Osteoblastic cells also regulate myeloma cell growth and increasing bone formation result in a reduction of tumoral burden in mice. Recent data suggest that ubiquitin-proteasome pathway, the major cellular degradative system and therapeutic target in myeloma cells, also regulates osteoblast differentiation. Further it has been demonstrated that different proteasome inhibitors may stimulate bone formation in mice. Finally, preliminary observations obtained in MM patients treated with the proteasome inhibitor Bortezomib show an increase of bone specific alkaline phosphatase in responder patients as compared to non-responder ones. Currently it is not know whether the proteasome inhibitor Bortezomib may have a direct effect on osteoblast and bone formation in vitro human cultures and in vivo in MM patients. To clarify this issue first we checked the effect of Bortezomib either on osteoblast differentiation and formation or on osteoblast proliferation, survival and function. In long-term human BM cultures we found that Bortezomib did not reduce the number of both early bone marrow (BM) osteoblast progenitors Colony Forming Unit-Fibroblast (CFU-F) and late ones Colony Forming Bone nodules (CFU-OB). On the other hand we found that Bortezomib (2–3 nM) significantly induced osteoblast phenotype in human mesenchymal cells incubated in presence of osteogenic factors. A stimulatory effect on osteoblast markers was observed after 24 hours of Bortezomib treatment. Consistently we found that Bortezomib significantly increased the activity of the transcription factor Runx2/Cbfa1 in human osteoblast progenitors without affecting the canonical WNT signaling pathway checked by the evaluation of nuclear and cytoplasmatic active beta-catenin levels. Using the human osteoblast like cells MG-63 and immortalized normal osteoblasts (HOBIT) we found that Bortezomib at concentration ranging between 2nM and 5nM did not inhibit osteoblast proliferation or induce osteoblast apoptosis. Similarly, Bortezomib did not affect the expression of osteoblast markers, Runx2/Cbfa1 activity and WNT signaling in both MG-63 and HOBIT cells. To extent our in vitro observation we have evaluated the potential effect of Bortezomib in vivo in MM patients. Bone histomorphometry as well as immunostainig for Runx2/Cbfa1 and beta-catenin was performed on BM biopsies obtained from 15 MM patients before and after 6–8 cycles of Bortezomib administrated in mono-therapy. A significant increase in the number of osteoblastic cells X mm2 of bone tissue and in the number of Runx2/Cbfa1 positive osteoblastic cells was observed only in responder patients showing an early increase of the serum alkaline phosphatase. In conclusion our data indicate that Bortezomib may increase osteoblast differentiation in human mesenchymal cells without affecting the proliferation, survival and function of mature osteoblasts. In vivo and in vitro observations support the hypothesis that both direct and indirect effects on bone formation process could occur during Bortezomib treatment.

scholarly journals SLITRK5 is a negative regulator of hedgehog signaling in osteoblasts

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jun Sun ◽  
Dong Yeon Shin ◽  
Mark Eiseman ◽  
Alisha R. Yallowitz ◽  
Na Li ◽  
...  
Keyword(s):  
Bone Formation ◽  
Primary Cilium ◽  
Hedgehog Signaling ◽  
Osteoblast Differentiation ◽  
Transmembrane Protein ◽  
Negative Regulator ◽  
Skeletal Mineralization ◽  
Enhance Bone Formation

AbstractHedgehog signaling is essential for bone formation, including functioning as a means for the growth plate to drive skeletal mineralization. However, the mechanisms regulating hedgehog signaling specifically in bone-forming osteoblasts are largely unknown. Here, we identified SLIT and NTRK-like protein-5(Slitrk5), a transmembrane protein with few identified functions, as a negative regulator of hedgehog signaling in osteoblasts. Slitrk5 is selectively expressed in osteoblasts and loss of Slitrk5 enhanced osteoblast differentiation in vitro and in vivo. Loss of SLITRK5 in vitro leads to increased hedgehog signaling and overexpression of SLITRK5 in osteoblasts inhibits the induction of targets downstream of hedgehog signaling. Mechanistically, SLITRK5 binds to hedgehog ligands via its extracellular domain and interacts with PTCH1 via its intracellular domain. SLITRK5 is present in the primary cilium, and loss of SLITRK5 enhances SMO ciliary enrichment upon SHH stimulation. Thus, SLITRK5 is a negative regulator of hedgehog signaling in osteoblasts that may be attractive as a therapeutic target to enhance bone formation.

Ultrastructure of melanocyte-keratinocyte interactions and pigment transfer in vitro

1978 ◽  
Vol 36 (2) ◽  
pp. 650-651
Author(s):  
Raul I. Garcia ◽  
Evelyn A. Flynn ◽  
George Szabo
Keyword(s):  
Direct Injection ◽  
Skin Pigmentation ◽  
Freeze Fracture ◽  
Pigment Granule ◽  
Time Lapse ◽  
Ultrastructural Level ◽  
Lanthanum Tracer ◽  
A Cell

Skin pigmentation in mammals involves the interaction of epidermal melanocytes and keratinocytes in the structural and functional unit known as the Epidermal Melanin Unit. Melanocytes(M) synthesize melanin within specialized membrane-bound organelles, the melanosome or pigment granule. These are subsequently transferred by way of M dendrites to keratinocytes(K) by a mechanism still to be clearly defined. Three different, though not necessarily mutually exclusive, mechanisms of melanosome transfer have been proposed: cytophagocytosis by K of M dendrite tips containing melanosomes, direct injection of melanosomes into the K cytoplasm through a cell-to-cell pore or communicating channel formed by localized fusion of M and K cell membranes, release of melanosomes into the extracellular space(ECS) by exocytosis followed by K uptake using conventional phagocytosis. Variability in methods of transfer has been noted both in vivo and in vitro and there is evidence in support of each transfer mechanism. We Have previously studied M-K interactions in vitro using time-lapse cinemicrography and in vivo at the ultrastructural level using lanthanum tracer and freeze-fracture.

Analysis of the Dynamics of the Electric Capacitance of a Cell Monolayer at the Late Stages of Caco-2 cell Differentiation

2019 ◽  
Vol 35 (6) ◽  
pp. 87-90
Author(s):  
S.V. Nikulin ◽  
V.A. Petrov ◽  
D.A. Sakharov
Keyword(s):  
Impedance Spectroscopy ◽  
Cell Monolayer ◽  
Microfluidic Chips ◽  
Russian Science ◽  
Electric Capacitance ◽  
A Cell ◽  
Static Conditions ◽  
Late Stages

The real-time monitoring of electric capacitance (impedance spectroscopy) allowed obtaining evidence that structures which look like intestinal villi can be formed during the cultivation under static conditions as well as during the cultivation in microfluidic chips. It was shown in this work via transcriptome analysis that the Hh signaling pathway is involved in the formation of villus-like structures in vitro, which was previously shown for their formation in vivo. impedance spectroscopy, intestine, villi, electric capacitance, Hh The study was funded by the Russian Science Foundation (Project 16-19-10597).

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