scholarly journals Myeloid Lineage Ablation of Phlpp1 Regulates M-CSF Signaling and Tempers Bone Resorption in Female Mice

2021 ◽  
Vol 22 (18) ◽  
pp. 9702
Author(s):  
Ismael Y. Karkache ◽  
Jeyaram R. Damodaran ◽  
David H. H. Molstad ◽  
Kim C. Mansky ◽  
Elizabeth W. Bradley
Keyword(s):  
Bone Resorption ◽  
Bone Mass ◽  
Cell Types ◽  
Serum Markers ◽  
In Vitro Assays ◽  
Bovine Bone ◽  
Micro Computed Tomography ◽  
Myeloid Lineage ◽  
Trabecular Bone Mass

Prior work demonstrated that Phlpp1 deficiency alters trabecular bone mass and enhances M-CSF responsiveness, but the cell types and requirement of Phlpp1 for this effect were unclear. To understand the function of Phlpp1 within myeloid lineage cells, we crossed Phlpp1 floxed mice with mice harboring LysM-Cre. Micro-computed tomography of the distal femur of 12-week-old mice revealed a 30% increase in bone volume per total volume of Phlpp1 female conditional knockouts, but we did not observe significant changes within male Phlpp1 cKOLysM mice. Bone histomorphmetry of the proximal tibia further revealed that Phlpp1 cKOLysM females exhibited elevated osteoclast numbers, but conversely had reduced levels of serum markers of bone resorption as compared to littermate controls. Osteoblast number and serum markers of bone formation were unchanged. In vitro assays confirmed that Phlpp1 ablation enhanced osteoclast number and area, but limited bone resorption. Additionally, reconstitution with exogenous Phlpp1 suppressed osteoclast numbers. Dose response assays demonstrated that Phlpp1−/− cells are more responsive to M-CSF, but reconstitution with Phlpp1 abrogated this effect. Furthermore, small molecule-mediated Phlpp inhibition enhanced osteoclast numbers and size. Enhanced phosphorylation of Phlpp substrates—including Akt, ERK1/2, and PKCζ—accompanied these observations. In contrast, actin cytoskeleton disruption occurred within Phlpp inhibitor treated osteoclasts. Moreover, Phlpp inhibition reduced resorption of cells cultured on bovine bone slices in vitro. Our results demonstrate that Phlpp1 deficiency within myeloid lineage cells enhances bone mass by limiting bone resorption while leaving osteoclast numbers intact; moreover, we show that Phlpp1 represses osteoclastogenesis and controls responses to M-CSF.

scholarly journals Microglia in Neurodegenerative Events—An Initiator or a Significant Other?

2021 ◽  
Vol 22 (11) ◽  
pp. 5818
Author(s):  
Gaylia Jean Harry
Keyword(s):  
Neurovascular Unit ◽  
Cell Types ◽  
In Vitro Assays ◽  
Significant Other ◽  
Neurodegenerative Process ◽  
Target Sites ◽  
Systemic Factors ◽  
Injury And Repair ◽  
The Brain

A change in microglia structure, signaling, or function is commonly associated with neurodegeneration. This is evident in the patient population, animal models, and targeted in vitro assays. While there is a clear association, it is not evident that microglia serve as an initiator of neurodegeneration. Rather, the dynamics imply a close interaction between the various cell types and structures in the brain that orchestrate the injury and repair responses. Communication between microglia and neurons contributes to the physiological phenotype of microglia maintaining cells in a surveillance state and allows the cells to respond to events occurring in their environment. Interactions between microglia and astrocytes is not as well characterized, nor are interactions with other members of the neurovascular unit; however, given the influence of systemic factors on neuroinflammation and disease progression, such interactions likely represent significant contributes to any neurodegenerative process. In addition, they offer multiple target sites/processes by which environmental exposures could contribute to neurodegenerative disease. Thus, microglia at least play a role as a significant other with an equal partnership; however, claiming a role as an initiator of neurodegeneration remains somewhat controversial.

scholarly journals Single-cell analysis revealed that IL4I1 promoted ovarian cancer progression

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Hongyu Zhao ◽  
Yu Teng ◽  
Wende Hao ◽  
Jie Li ◽  
Zhefeng Li ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Single Cell ◽  
Cancer Progression ◽  
Cox Regression ◽  
Single Cell Analysis ◽  
Cell Types ◽  
In Vitro Assays ◽  
Migration And Invasion ◽  
Dominant Type

Abstract Background Ovarian cancer was one of the leading causes of female deaths. Patients with OC were essentially incurable and portends a poor prognosis, presumably because of profound genetic heterogeneity limiting reproducible prognostic classifications. Methods We comprehensively analyzed an ovarian cancer single-cell RNA sequencing dataset, GSE118828, and identified nine major cell types. Relationship between the clusters was explored with CellPhoneDB. A malignant epithelial cluster was confirmed using pseudotime analysis, CNV and GSVA. Furthermore, we constructed the prediction model (i.e., RiskScore) consisted of 10 prognosis-specific genes from 2397 malignant epithelial genes using the LASSO Cox regression algorithm based on public datasets. Then, the prognostic value of Riskscore was assessed with Kaplan–Meier survival analysis and time-dependent ROC curves. At last, a series of in-vitro assays were conducted to explore the roles of IL4I1, an important gene in Riskscore, in OC progression. Results We found that macrophages possessed the most interaction pairs with other clusters, and M2-like TAMs were the dominant type of macrophages. C0 was identified as the malignant epithelial cluster. Patients with a lower RiskScore had a greater OS (log-rank P < 0.01). In training set, the AUC of RiskScore was 0.666, 0.743 and 0.809 in 1-year, 3-year and 5-year survival, respectively. This was also validated in another two cohorts. Moreover, downregulation of IL4I1 inhibited OC cells proliferation, migration and invasion. Conclusions Our work provide novel insights into our understanding of the heterogeneity among OCs, and would help elucidate the biology of OC and provide clinical guidance in prognosis for OC patients.

scholarly journals Network Pharmacology-Based Strategy for the Investigation of the Anti-Osteoporosis Effects and Underlying Mechanism of Zhuangguguanjie Formulation

2021 ◽  
Vol 12 ◽  
Author(s):  
Wang Gong ◽  
Xingren Chen ◽  
Tianshu Shi ◽  
Xiaoyan Shao ◽  
Xueying An ◽  
...  
Keyword(s):  
Bone Resorption ◽  
Bone Formation ◽  
Bone Mass ◽  
Signaling Pathway ◽  
Osteoclast Differentiation ◽  
Enrichment Analysis ◽  
Underlying Mechanism ◽  
Network Pharmacology ◽  
Biological Processes

As the society is aging, the increasing prevalence of osteoporosis has generated huge social and economic impact, while the drug therapy for osteoporosis is limited due to multiple targets involved in this disease. Zhuangguguanjie formulation (ZG) is extensively used in the clinical treatment of bone and joint diseases, but the underlying mechanism has not been fully described. This study aimed to examine the therapeutic effect and potential mechanism of ZG on postmenopausal osteoporosis. The ovariectomized (OVX) mice were treated with normal saline or ZG for 4 weeks after ovariectomy following a series of analyses. The bone mass density (BMD) and trabecular parameters were examined by micro-CT. Bone remodeling was evaluated by the bone histomorphometry analysis and ELISA assay of bone turnover biomarkers in serum. The possible drug–disease common targets were analyzed by network pharmacology. To predict the potential biological processes and related pathways, GO/KEGG enrichment analysis was performed. The effects of ZG on the differentiation phenotype of osteoclasts and osteoblasts and the predicted pathway were verified in vitro. The results showed that ZG significantly improved the bone mass and micro-trabecular architecture in OVX mice compared with untreated OVX mice. ZG could promote bone formation and inhibit bone resorption to ameliorate ovariectomy-induced osteoporosis as evidenced by increased number of osteoblast (N.Ob/Tb.Pm) and decreased number of osteoclast (N.Oc/Tb.Pm) in treated group compared with untreated OVX mice. After identifying potential drug–disease common targets by network pharmacology, GO enrichment analysis predicted that ZG might affect various biological processes including osteoblastic differentiation and osteoclast differentiation. The KEGG enrichment analysis suggested that PI3K/Akt and mTOR signaling pathways could be the possible pathways. Furthermore, the experiments in vitro validated our findings. ZG significantly down-regulated the expression of osteoclast differentiation markers, reduced osteoclastic resorption, and inhibited the phosphorylation of PI3K/Akt, while ZG obviously up-regulated the expression of osteogenic biomarkers, promoted the formation of calcium nodules, and hampered the phosphorylation of 70S6K1/mTOR, which can be reversed by the corresponding pathway activator. Thus, our study suggested that ZG could inhibit the PI3K/Akt signaling pathway to reduce osteoclastic bone resorption as well as hamper the mTORC1/S6K1 signaling pathway to promote osteoblastic bone formation.

scholarly journals Anti-HMGB1 Neutralizing Antibody Attenuates Periodontal Inflammation and Bone Resorption in a Murine Periodontitis Model

2018 ◽  
Vol 86 (5) ◽  
Author(s):  
Chiaki Yoshihara-Hirata ◽  
Keisuke Yamashiro ◽  
Tadashi Yamamoto ◽  
Hiroaki Aoyagi ◽  
Hidetaka Ideguchi ◽  
...  
Keyword(s):  
Bone Resorption ◽  
Neutralizing Antibody ◽  
Myeloperoxidase Activity ◽  
Micro Computed Tomography ◽  
Gm Csf ◽  
Periodontal Inflammation ◽  
Periodontal Infection ◽  
Tnf Α ◽  
Inflammatory Stimuli

ABSTRACTHigh mobility group box 1 (HMGB1) is a non-histone DNA-binding protein that is secreted into the extracellular milieu in response to inflammatory stimuli. The secreted HMGB1 mediates various inflammatory diseases, including periodontitis; however, the underlying mechanisms of HMGB1-induced periodontal inflammation are not completely understood. Here, we examined whether anti-HMGB1 neutralizing antibody inhibits periodontal progression and investigated the molecular pathology of HMGB1in vitroandin vivo. In vitroanalysis indicated that HMGB1, granulocyte-macrophage colony-stimulating factor (GM-CSF), and interleukin-1β (IL-1β) were secreted in response to tumor necrosis factor-α (TNF-α) stimuli in human gingival epithelial cells (HGECs) and human monocytic leukemia cells (THP-1) treated with phorbol myristate acetate. Increased levels of GM-CSF and IL-1β were observed in the conditioned media from TNF-α-stimulated HGECs and THP-1in vitro. Simultaneous stimulation with TNF-α and anti-HMGB1 antibody significantly decreased TNF-α-induced inflammatory cytokine secretion. Experimental periodontitis was induced in mice usingPorphyromonas gingivalis-soaked ligatures. The extracellular translocation was confirmed in gingival epithelia in the periodontitis model mice by immunofluorescence analysis. Systemic administration of anti-HMGB1 neutralizing antibody significantly inhibited translocation of HMGB1. The anti-HMGB1 antibody inhibited periodontal inflammation, expression of IL-1β and C-X-C motif chemokine ligand 1 (CXCL1), migration of neutrophils, and bone resorption, shown by bioluminescence imaging of myeloperoxidase activity, quantitative reverse transcription-PCR (RT-PCR), and micro-computed tomography analysis. These findings indicate that HMGB1 is secreted in response to inflammatory stimuli caused by periodontal infection, which is crucial for the initiation of periodontitis, and the anti-HMGB1 antibody attenuates the secretion of a series of inflammatory cytokines, consequently suppressing the progression of periodontitis.

scholarly journals Constitutive Activation of β-Catenin in Differentiated Osteoclasts Induces Bone Loss in Mice

2018 ◽  
Vol 48 (5) ◽  
pp. 2091-2102 ◽  
Author(s):  
Xin Sui ◽  
Shijian Deng ◽  
Mengmeng Liu ◽  
Linlin Fan ◽  
Yunfei Wang ◽  
...  
Keyword(s):  
Bone Loss ◽  
Bone Mass ◽  
Bone Growth ◽  
Osteoclast Differentiation ◽  
Marker Genes ◽  
Tartrate Resistant Acid Phosphatase ◽  
Bone Homeostasis ◽  
Micro Computed Tomography ◽  
Constitutive Activation

Background/Aims: Activation of the Wnt/β-catenin signalling pathway has been widely investigated in bone biology and shown to promote bone formation. However, its specific effects on osteoclast differentiation have not been fully elucidated. Our study aimed to identify the role of β-catenin in osteoclastogenesis and bone homeostasis. Methods: In the present study, exon 3 in the β-catenin gene (Ctnnb1) allele encoding phosphorylation target serine/threonine residues was flanked by floxP sequences. We generated mice exhibiting conditional β-catenin activation (Ctsk-Cre;Ctnnb1flox(exon3)/+, designated CA-β-catenin) by crossing Ctnnb1flox(exon3)/flox(exon3) mice with osteoclast-specific Ctsk-Cre mice. Bone growth and bone mass were analysed by micro-computed tomography (micro-CT) and histomorphometry. To further examine osteoclast activity, osteoclasts were induced from bone marrow monocytes (BMMs) isolated from CA-β-catenin and Control mice in vitro. Osteoclast differentiation was detected by tartrate-resistant acid phosphatase (TRAP) staining, immunofluorescence staining and reverse transcription-quantitative PCR (RT–qPCR) analysis. Results: Growth retardation and low bone mass were observed in CA-β-catenin mice. Compared to controls, CA-β-catenin mice had significantly reduced trabecular bone numbers under growth plates as well as thinner cortical bones. Moreover, increased TRAP-positive osteoclasts were observed on the surfaces of trabecular bones and cortical bones in the CA-β-catenin mice; consistent results were observed in vitro. In the CA-β-catenin group, excessive numbers of osteoclasts were induced from BMMs, accompanied by the increased expression of osteoclast-associated marker genes. Conclusion: These results indicated that the constitutive activation of β-catenin in osteoclasts promotes osteoclast formation, resulting in bone loss.

scholarly journals Robust and Scalable Angiogenesis Assay of Perfused 3D Human iPSC-Derived Endothelium for Anti-Angiogenic Drug Screening

2020 ◽  
Vol 21 (13) ◽  
pp. 4804
Author(s):  
Vincent van Duinen ◽  
Wendy Stam ◽  
Eva Mulder ◽  
Farbod Famili ◽  
Arie Reijerkerk ◽  
...  
Keyword(s):  
Drug Screening ◽  
Cell Formation ◽  
Cell Types ◽  
Culture Conditions ◽  
In Vitro Assays ◽  
Vegf Receptor ◽  
Screening Assay ◽  
Angiogenesis Assay

To advance pre-clinical vascular drug research, in vitro assays are needed that closely mimic the process of angiogenesis in vivo. Such assays should combine physiological relevant culture conditions with robustness and scalability to enable drug screening. We developed a perfused 3D angiogenesis assay that includes endothelial cells (ECs) from induced pluripotent stem cells (iPSC) and assessed its performance and suitability for anti-angiogenic drug screening. Angiogenic sprouting was compared with primary ECs and showed that the microvessels from iPSC-EC exhibit similar sprouting behavior, including tip cell formation, directional sprouting and lumen formation. Inhibition with sunitinib, a clinically used vascular endothelial growth factor (VEGF) receptor type 2 inhibitor, and 3-(3-pyridinyl)-1-(4-pyridinyl)-2-propen-1-one (3PO), a transient glycolysis inhibitor, both significantly reduced the sprouting of both iPSC-ECs and primary ECs, supporting that both cell types show VEGF gradient-driven angiogenic sprouting. The assay performance was quantified for sunitinib, yielding a minimal signal window of 11 and Z-factor of at least 0.75, both meeting the criteria to be used as screening assay. In conclusion, we have developed a robust and scalable assay that includes physiological relevant culture conditions and is amenable to screening of anti-angiogenic compounds.

scholarly journals Kidney-based in vitro models for drug-induced toxicity testing

2019 ◽  
Vol 93 (12) ◽  
pp. 3397-3418 ◽  
Author(s):  
João Faria ◽  
Sabbir Ahmed ◽  
Karin G. F. Gerritsen ◽  
Silvia M. Mihaila ◽  
Rosalinde Masereeuw
Keyword(s):  
Adverse Effects ◽  
Drug Disposition ◽  
Drug Effects ◽  
Toxicity Testing ◽  
Cell Types ◽  
In Vitro Assays ◽  
Vascular Effects ◽  
Drug Induced

Abstract The kidney is frequently involved in adverse effects caused by exposure to foreign compounds, including drugs. An early prediction of those effects is crucial for allowing novel, safe drugs entering the market. Yet, in current pharmacotherapy, drug-induced nephrotoxicity accounts for up to 25% of the reported serious adverse effects, of which one-third is attributed to antimicrobials use. Adverse drug effects can be due to direct toxicity, for instance as a result of kidney-specific determinants, or indirectly by, e.g., vascular effects or crystals deposition. Currently used in vitro assays do not adequately predict in vivo observed effects, predominantly due to an inadequate preservation of the organs’ microenvironment in the models applied. The kidney is highly complex, composed of a filter unit and a tubular segment, together containing over 20 different cell types. The tubular epithelium is highly polarized, and the maintenance of this polarity is critical for optimal functioning and response to environmental signals. Cell polarity is dependent on communication between cells, which includes paracrine and autocrine signals, as well as biomechanic and chemotactic processes. These processes all influence kidney cell proliferation, migration, and differentiation. For drug disposition studies, this microenvironment is essential for prediction of toxic responses. This review provides an overview of drug-induced injuries to the kidney, details on relevant and translational biomarkers, and advances in 3D cultures of human renal cells, including organoids and kidney-on-a-chip platforms.

Interferon-Gamma Induces Monopoiesis and Inhibits Neutrophil Development During Inflammation

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1320-1320
Author(s):  
Alexander M. de Bruin ◽  
Marijke G. Valkhof ◽  
Louis Boon ◽  
Ivo P. Touw ◽  
Martijn A. Nolte
Keyword(s):  
Viral Infection ◽  
Interferon Gamma ◽  
Molecular Mechanisms ◽  
Conflicts Of Interest ◽  
Myeloid Cell ◽  
Cell Types ◽  
In Vitro Assays ◽  
Stat3 Phosphorylation ◽  
Proliferation And Differentiation

Abstract Abstract 1320 Steady-state hematopoiesis is altered upon infection, but the cellular and molecular mechanisms driving these changes are largely unknown. Modulation of hematopoiesis is essential to increase the output of the appropriate type of effector cell required to combat the invading pathogen. Here we demonstrate that the pro-inflammatory cytokine interferon-gamma (IFNγ) is involved in orchestrating inflammation-induced myelopoiesis. Using both mouse models and in vitro assays we show that IFNg induces differentiation of monocytes over neutrophils at the level of myeloid progenitors. We show that acute viral infection induces monopoiesis in WT mice, but a strongly increased neutrophil production in IFNγ−/− mice. When exploring the underlying molecular mechanism, we found that IFNγ increases expression of the monocyte-inducing transcription factors PU.1 and IRF8 in granulocyte-macrophage progenitors (GMPs) and enhances the response of these cells to M-CSF. On the contrary, IFNγ inhibits proliferation and differentiation of GMPs in response to G-CSF. We demonstrate that IFNγ reduces G-CSF-induced phosphorylation of STAT3, an important transcription factor in neutrophil development. Moreover, IFNγ also induces expression of SOCS3, which is a negative feedback regulator of G-CSFR signaling; by using G-CSFR mutants we demonstrate that the IFNγ-mediated inhibition of G-CSF-driven STAT3 phosphorylation is dependent on the recruitment of SOCS3 to the G-CSFR. In conclusion, our findings illustrate that IFNγ is an important factor in shaping the hematopoietic response during inflammation. IFNγ is able to regulate myelopoiesis in the bone marrow upon viral infection by promoting the production of the appropriate myeloid cell type, but also by actively suppressing formation of cells less important for anti-viral defense. In addition, our data provide a molecular explanation for the observed aberrant hematopoietic remodeling observed in pathogen-challenged IFNγ-deficient mice. As both monocytes and neutrophils play important, but distinct roles in the defense against numerous pathogens, this study provides important new insight in the mechanism that regulates the formation of these vital myeloid cell types during infections. Disclosures: No relevant conflicts of interest to declare.

scholarly journals The Microtubule Plus-End Proteins EB1 and Dynactin Have Differential Effects on Microtubule Polymerization

2003 ◽  
Vol 14 (4) ◽  
pp. 1405-1417 ◽  
Author(s):  
Lee A. Ligon ◽  
Spencer S. Shelly ◽  
Mariko Tokito ◽  
Erika L.F. Holzbaur
Keyword(s):  
Cultured Cells ◽  
Cell Types ◽  
Microtubule Dynamics ◽  
In Vitro Assays ◽  
Nucleation Effect ◽  
Microtubule Polymerization ◽  
The Individual ◽  
Different Cell Types ◽  
Dynactin Complex

Several microtubule-binding proteins including EB1, dynactin, APC, and CLIP-170 localize to the plus-ends of growing microtubules. Although these proteins can bind to microtubules independently, evidence for interactions among them has led to the hypothesis of a plus-end complex. Here we clarify the interaction between EB1 and dynactin and show that EB1 binds directly to the N-terminus of the p150Glued subunit. One function of a plus-end complex may be to regulate microtubule dynamics. Overexpression of either EB1 or p150Glued in cultured cells bundles microtubules, suggesting that each may enhance microtubule stability. The morphology of these bundles, however, differs dramatically, indicating that EB1 and dynactin may act in different ways. Disruption of the dynactin complex augments the bundling effect of EB1, suggesting that dynactin may regulate the effect of EB1 on microtubules. In vitro assays were performed to elucidate the effects of EB1 and p150Glued on microtubule polymerization, and they show that p150Gluedhas a potent microtubule nucleation effect, whereas EB1 has a potent elongation effect. Overall microtubule dynamics may result from a balance between the individual effects of plus-end proteins. Differences in the expression and regulation of plus-end proteins in different cell types may underlie previously noted differences in microtubule dynamics.

scholarly journals Tyrosine Phosphatase Epsilon Is a Positive Regulator of Osteoclast Function in Vitro and In Vivo

2004 ◽  
Vol 15 (1) ◽  
pp. 234-244 ◽  
Author(s):  
Riccardo Chiusaroli ◽  
Hilla Knobler ◽  
Chen Luxenburg ◽  
Archana Sanjay ◽  
Shira Granot-Attas ◽  
...  
Keyword(s):  
Bone Resorption ◽  
Bone Metabolism ◽  
Tyrosine Phosphatase ◽  
Serum Levels ◽  
Normal Serum ◽  
Bone Degradation ◽  
Trabecular Bone Mass ◽  
Osteoclast Function

Protein tyrosine phosphorylation is a major regulator of bone metabolism. Tyrosine phosphatases participate in regulating phosphorylation, but roles of specific phosphatases in bone metabolism are largely unknown. We demonstrate that young (<12 weeks) female mice lacking tyrosine phosphatase epsilon (PTPϵ) exhibit increased trabecular bone mass due to cell-specific defects in osteoclast function. These defects are manifested in vivo as reduced association of osteoclasts with bone and as reduced serum concentration of C-terminal collagen telopeptides, specific products of osteoclast-mediated bone degradation. Osteoclast-like cells are generated readily from PTPϵ-deficient bone-marrow precursors. However, cultures of these cells contain few mature, polarized cells and perform poorly in bone resorption assays in vitro. Podosomes, structures by which osteoclasts adhere to matrix, are disorganized and tend to form large clusters in these cells, suggesting that lack of PTPϵ adversely affects podosomal arrangement in the final stages of osteoclast polarization. The gender and age specificities of the bone phenotype suggest that it is modulated by hormonal status, despite normal serum levels of estrogen and progesterone in affected mice. Stimulation of bone resorption by RANKL and, surprisingly, Src activity and Pyk2 phosphorylation are normal in PTPϵ-deficient osteoclasts, indicating that loss of PTPϵ does not cause widespread disruption of these signaling pathways. These results establish PTPϵ as a phosphatase required for optimal structure, subcellular organization, and function of osteoclasts in vivo and in vitro.

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