scholarly journals Primary cilia respond to intermittent low-magnitude, high-frequency vibration and mediate vibration-induced effects in osteoblasts

2020 ◽  
Vol 318 (1) ◽  
pp. C73-C82 ◽  
Author(s):  
Yan-Hui Li ◽  
Dong Zhu ◽  
Zongbing Cao ◽  
Yanwei Liu ◽  
Jian Sun ◽  
...  

Our objective was to investigate the role of primary cilia in low-magnitude, high-frequency vibration (LMHFV) treatment of MC3T3-E1 osteoblasts (OBs). We used chloral hydrate (CH), which has a well-characterized function in chemically removing primary cilia, to elucidate the role of primary cilia in LMHFV-induced OB osteogenic responses through cell viability assay, Western blot analysis, real-time quantitative RT-PCR, and histochemical staining methods. We observed a significant, 30% decrease in the number of MC3T3-E1 OBs with primary cilia (reduced from 64.3 ± 5%) and an approximately 50% reduction in length of primary cilia (reduced from 3 ± 0.8 μm) after LMHFV stimulation. LMHFV stimulation upregulated protein expression of the bone matrix markers collagen 1 (COL-1), osteopontin (OPN), and osteoclacin(OCN) in MC3T3-E1 OBs, indicating that LMHFV induces osteogenesis. High-concentration or long-duration CH exposure resulted in inhibition of MC3T3-E1 OB survival. In addition, Western blot analysis and RT-PCR revealed that CH treatment prevented LMHFV-induced osteogenesis. Furthermore, decreased alkaline phosphate activity, reduced OB differentiation, mineralization, and maturation were observed in CH-pretreated and LMHFV-treated OBs. We showed that LMHFV induces morphological changes in primary cilia that may fine-tune their mechanosensitivity. In addition, we demonstrated the significant inhibition by CH of LMHFV-induced OB mineralization, maturation, and differentiation, which might reveal the critical role of primary cilia in the process.

2018 ◽  
Vol 48 (3) ◽  
pp. 1003-1011 ◽  
Author(s):  
Li-Ying Zhou ◽  
Heng Zeng ◽  
Shuo Wang ◽  
Jian-Xiong Chen

Background/Aims: Liver disease is a leading cause of high mortality and morbidity worldwide. The aim of the present study is to investigate the regulatory role of prolyl hydroxylase-2 (PHD2)-hypoxia-inducible factor-2a (HIF-2α) axis on nonalcoholic fatty liver disease (NAFLD) and to explore the potential mechanisms by which endothelial (EC)-specific PHD2 deficiency regulates hepatic steatosis and fibrosis. Methods: In the endothelial-specific PHD2 knockout (PHD2ECKO) mouse fed with normal diet or high fat diet (HFD), liver lipid accumulation and fibrosis were measured by Oil Red O and Masson trichrome staining. The fat and body weight (FW/BW) ratio and glucose tolerance were measured. The expression of HIF-2α, atrial natriuretic peptide (ANP), angiopoietin-2 (Ang-2), and transforming growth factor-b (TGF-β) were analyzed by western blot analysis. Results: The steatosis and fibrosis were significantly increased in the PHD2ECKO mice. FW/BW ratio was significantly increased in the PHD2ECKO mice. Moreover, knockout of endothelial PHD2 resulted in an impairment of glucose tolerance in mice. Western blot analysis showed that the expression of HIF-2α in liver tissues was not significantly increased. Interestingly, the expression of ANP was decreased, and Ang-2 and TGF-β levels were significantly increased in the liver of PHD2ECKO mice. The FW/BW ratio was also significantly increased in the PHD2ECKO mice fed with HFD for 16 weeks. Feeding HFD resulted in a significant increase in hepatic steatosis in the control PHD2f/f mice, but did not further enhance hepatic steatosis in the PHD2ECKO mice. Conclusions: We concluded that the endothelial PHD2 plays a critical role in hepatic steatosis and fibrosis, which may be involved in the regulation of ANP and Ang-2/TGF-β signaling pathway, but not the HIF-2α expression.


2000 ◽  
Vol 278 (2) ◽  
pp. G197-G206 ◽  
Author(s):  
J. Praetorius ◽  
D. Andreasen ◽  
B. L. Jensen ◽  
M. A. Ainsworth ◽  
U. G. Friis ◽  
...  

Na+/H+-exchangers (NHE) mediate acid extrusion from duodenal epithelial cells, but the isoforms involved have not previously been determined. Thus we investigated 1) the contribution of Na+-dependent processes to acid extrusion, 2) sensitivity to Na+/H+ exchange inhibitors, and 3) molecular expression of NHE isoforms. By fluorescence spectroscopy the recovery of intracellular pH (pHi) was measured on suspensions of isolated acidified murine duodenal epithelial cells loaded with 2′,7′-bis(2-carboxyethyl)-5(6)-carboxyfluorescein. Expression of NHE isoforms was studied by RT-PCR and Western blot analysis. Reduction of extracellular Na+ concentration ([Na+]o) during pHirecovery decreased H+ efflux to minimally 12.5% of control with a relatively high apparent Michaelis constant for extracellular Na+. The Na+/H+exchange inhibitors ethylisopropylamiloride and amiloride inhibited H+ efflux maximally by 57 and 80%, respectively. NHE1, NHE2, and NHE3 were expressed at the mRNA level (RT-PCR) as well as at the protein level (Western blot analysis). On the basis of the effects of low [Na+]o and inhibitors we propose that acid extrusion in duodenal epithelial cells involves Na+/H+ exchange by isoforms NHE1, NHE2, and NHE3.


2018 ◽  
Vol 49 (3) ◽  
pp. 985-997 ◽  
Author(s):  
Weisen Wang ◽  
Zhi Wang ◽  
Dingyuan Tian ◽  
Xi Zeng ◽  
Yangdong Liu ◽  
...  

Background/Aims: Neointimal hyperplasia is responsible for stenosis, which requires corrective vascular surgery, and is also a major morphological feature of many cardiovascular diseases. This hyperplasia involves the endothelial-to-mesenchymal transition (EndMT). We investigated whether integrin β3 can modulate the EndMT, as well as its underlying mechanism. Methods: Integrin β3 was overexpressed or knocked down in human umbilical vein endothelial cells (HUVECs). The expression of endothelial markers and mesenchymal markers was determined by real-time reverse transcription PCR (RT-PCR), immunofluorescence staining, and western blot analysis. Notch signaling pathway components were detected by real-time RT-PCR and western blot analysis. Cell mobility was evaluated by wound-healing, Transwell, and spreading assays. Fibroblast-specific protein 1 (FSP-1) promoter activity was determined by luciferase assay. Results: Transforming growth factor (TGF)-β1 treatment or integrin β3 overexpression significantly promoted the EndMT by downregulating VE-cadherin and CD31 and upregulating smooth muscle actin α and FSP-1 in HUVECs, and by enhancing cell migration. Knockdown of integrin β3 reversed these effects. Notch signaling was activated after TGF-β1 treatment of HUVECs. Knockdown of integrin β3 suppressed TGF-β1-induced Notch activation and expression of the Notch downstream target FSP-1. Conclusion: Integrin β3 may promote the EndMT in HUVECs through activation of the Notch signaling pathway.


2013 ◽  
Vol 33 (suppl_1) ◽  
Author(s):  
Rebekah Sian Hwee Yu ◽  
Daryll Baker ◽  
David Abraham ◽  
Janice Tsui

Objectives Erythropoietin (Epo) has tissue-protective effects in response to injury, acting through the EpoR-βcR heteroreceptor. We have previously demonstrated the presence and interaction of the EpoR and βcR in human skeletal muscle. Here we aim to investigate the potential cytoprotective effects of Epo and an Epo-derivative (ARA-290) in a human in vitro model of skeletal muscle and establish a potential downstream signalling pathway utilised in protecting cells from apoptosis (including Jak-2, PI3k/Akt, NFkB). Methods Gastrocnemius muscle biopsies were obtained from patients with critical limb ischaemia and control samples were obtained from non-ischaemic patients. Human myoblasts were isolated from muscle biopsies, cultured, and allowed to differentiate into myotubes in order to investigate the cytoprotective effects of Epo and ARA-290 on myotubes subjected to simulated ischaemia. The PI3k inhibitors, LY294002 and wortmannin, were then used to determine the role of PI3k/Akt pathway in mediating cytoprotection. Following this, inhibitors against the upstreatm (Jak-2) and downstream (NFkB) molecules were also investigated. Western blot analysis, using the pro-apoptotic marker cleaved caspase-3 was performed and compared with levels of Akt and phosphorylated-Akt, using western blot analysis. Results Exogenous administration of Epo and ARA-290 were able to ameliorate the ischaemia-induced apoptosis on isolated human myotubes as shown by a significant reduction in cleaved caspase-3 expression. Addition of all inhibitors, to ARA-290 or Epo pre-treated cells, abolished the reduction in apoptosis. Conclusion The ability of ARA-290 to attenuate apoptosis in human myotubes undergoing ischaemic insult suggests a potential role in tissue protection in skeletal muscle injury. We propose that the PI3k/Akt signalling pathway is involved in mediating this cytoprotection.


2019 ◽  
Vol 48 (3) ◽  
pp. 030006051988944 ◽  
Author(s):  
Yunfu Lv ◽  
Yejuan Li ◽  
Ning Liu ◽  
Yonghong Dong ◽  
Jie Deng

Objectives To evaluate the Th1/Th2 cell profile in spleens of cirrhotic and hypersplenic rats by investigating the expression of Th1-associated chemokine receptors CXCR3, CCR5 and Th2-associated chemokine receptor CCR3. Methods Experimental liver cirrhosis and hypersplenism were induced in rats by the intragastric administration of carbon tetrachloride (CCl4; 40% solution [0.3 ml/100g, twice/week for 8 weeks]) and confirmed by pathology and hemogram. Presence of the three chemokine receptors was investigated by real-time polymerase chain reaction (RT-PCR), immunohistochemical staining, and western blot analysis. Results By comparison with control animals (n=10), RT-PCR demonstrated that CXCR3 and CCR5-mRNA levels were significantly elevated in the hypersplenic rats (n=26) and CCR3-mRNA levels were lower. Immunohistochemical staining showed that by comparison with controls, the mean density of the Th1-associated CXCR3 and CCR5 receptors was significantly increased but there was no difference between groups in Th2-associated CCR3 receptors. Western blot analysis showed that by comparison with controls, hypersplenic rats had higher levels of CXCR3 and CCR5 protein but lower levels of CCR3 protein. Conclusions The abnormal expression of Th1-associated chemokine receptors in spleens of rats with cirrhosis and hypersplenism induced by CCL4 suggests that a functional imbalance between Th1/Th2 cells may play a role in the pathogenesis of hypersplenism.


2019 ◽  
Vol 51 (10) ◽  
pp. 1008-1015 ◽  
Author(s):  
Shusheng Qiu ◽  
Wei Hu ◽  
Qiuhong Ma ◽  
Yi Zhao ◽  
Liang Li ◽  
...  

Abstract Tumor necrosis factor α-induced protein 8-like-1 (TIPE1) functions as an activator or a repressor in a tumor cell type-specific manner. However, the role of TIPE1 in breast cancer, especially regarding metastasis, is unknown. In this study, we aimed to investigate the TIPE1 expression in breast cancer tissues, the biological functions, and the underlying mechanisms of TIPE1 regarding the metastatic properties of breast cancer cells. The results of immunohistochemical staining and western blot analysis indicated that TIPE1 expression was associated with tumor size and lymph node metastasis, and the expression of TIPE1 was downregulated in the tissues of patients with lymph node metastasis. Transwell and wound healing assay results showed that TIPE1 inhibited the invasive and migratory capacities of breast cancer cells. Moreover, the epithelial-mesenchymal transition (EMT) was suppressed in TIPE1-overexpressing cells, as demonstrated by western blot analysis. In addition, western blot analysis also showed that TIPE1 reduced the expression levels of MMP2 and MMP9 and decreased the phosphorylation level of ERK. These results suggested that TIPE1 might suppress the invasion and migration of breast cancer cells and inhibit EMT primarily via the ERK signaling pathway. Our findings revealed the anti-tumor metastasis role of TIPE1 in breast cancer and TIPE1 might be a new candidate prognostic indicator and a potential molecular target for the treatment of breast cancer.


2005 ◽  
Vol 2005 (4) ◽  
pp. 185-193 ◽  
Author(s):  
Jun-Hua Li ◽  
Jie-Ping Yu ◽  
Hong-Gang Yu ◽  
Xi-Ming Xu ◽  
Liang-Liang Yu ◽  
...  

Proinflammatory mediators are important in the pathogenesis of IBD, which are regulated by activation of NF-κB. The aim of this study was to investigate whether melatonin reduces inflammatory injury and inhibits proinflammatory molecule and NF-κB in rats with colitis. Rat colitis model was established by TNBS enema. NF-κB p65, TNF-α, ICAM-1, and IκBα in colon tissue were examined by immunohistochemistry, EMSA, RT-PCR, and Western blot analysis. Expression of proinflammatory molecule and activation of NF-κB were upregulated and IκB level decreased in rats with colitis. Melatonin reduces colonic inflammatory injury through downregulating proinflammatory molecule mediated by NF-κB inhibition and blockade of IκBα degradation.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4281-4281
Author(s):  
Zhiqing Wang ◽  
Yana Zhang ◽  
Arabinda Mandal ◽  
Jian Zhang ◽  
Francis J. Giles ◽  
...  

Abstract SLLP1 is a unique non-bacteriolytic c-lysozyme-like protein isolated from human spermatozoa. Antisera to SLLP1 blocks binding in the hamster egg penetration assay, suggesting that SLLP1 may be involved in sperm/egg adhesion. A recent study by dot blot analysis on RNA showed that SLLP1 was expressed only in the testis and in Burkitt lymphoma Raji cell line, suggesting that further studies are warranted to determine and characterize SLLP1 expression in tumor cells, in particular, fresh tumor specimens. Using a pair of sequence-specific primers in RT-PCR, we found that SLLP1 transcripts could be detected in 5/8 myeloma cell lines, suggesting that SLLP1 may be expressed in tumor cells from some hematologic malignancies. When we applied the investigations to 52 primary hematologic malignant specimens, SLLP1 transcripts were detected in 6/17 myeloma, 4/14 CML, 3/11 CLL, 2/9 AML and 0/1 hairy cell leukemia. In contrast, SLLP1 transcripts were not detected in the peripheral blood (n=12) or bone marrow (n=3) from any healthy donors. The specificity of the PCR products was confirmed by either sequence analysis or restriction digest with Pvu II. SLLP1 transcripts were translated into its corresponding protein in these tumor cells. Using tumor cell lysate in Western blot analysis, we detected SLLP1 protein in the myeloma cell lines and also in fresh malignant specimens, although positivities were only observed in specimens with high RT-PCR signals. All PCR-negative specimens were also negative in Western blot analysis. The specificity of the Western blot signals were confirmed in all cases by blocking assays with a high concentration of recombinant SLLP1 protein. We next investigated the expression of SLLP1 in a large panel of normal tissues using RT-PCR and real time quantitative PCR. Both approaches showed that SLLP1 is a novel Cancer-Testis antigen in hematologic malignancies. SLLP1 was detected, at a level of 8206 copies/0.25 mcg total RNA, only in normal testis. We also found that the SLLP1 mRNA copy numbers in fresh hematologic tumor specimens were up to 2316 copies/0.25 mcg total RNA, i.e. more than 25% of the level found in normal testis. We cloned and generated SLLP1 recombinant protein from E coli and used the purified recombinant SLLP1 in an ELISA system to detect anti-SLLP1 antibodies. Using sera from 24 healthy donors and the mean + 2SD as the cut-off signal intensities, we found that high titer IgG antibodies directed at SLLP1 could be detected in the sera from 2/9 AML, 5/23 CLL, 6/27 CML and 14/51 myeloma patients. The specificity of the antibodies was confirmed in Western blot analysis. Probably due to the decreased sensitivity of the detection system in Western blot analysis, only 1/2 AML, 3/5 CLL, 4/6 CML and 7/14 myeloma SLLP1 antibody+ sera produced a signal in the Western blot analysis. Interesting, IgG2 was by far the commonest SLLP1 antibodies in these patients. There was a good correlation between SLLP1 gene expression and immune responses. In summary, SLLP1 is a novel CT antigen in hematologic malignancies and is capable of eliciting B-cell immune responses in vivo in cancer-bearing patients. Our results support SLLP1 as a protein target appropriate for further in vitro study to define its suitability for immunotherapy.


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1267-1267
Author(s):  
Haiming Chen ◽  
Mingjie Li ◽  
Richard A. Campbell ◽  
Melinda S. Gordon ◽  
Dror Shalitin ◽  
...  

Abstract We have discovered a novel mechanism leading to blood vessel formation involving transdifferentiation of monocytes into endothelial cells by tumor cell production of pleiotrophin (PTN), a protein highly produced by myeloma (H. Chen et al, Blood, 2005; Yeh et al BJH, 2006). Arsenic trioxide (ATO) induces apoptosis of cancer cells directly through a number of mechanisms, and this drug has also been shown to inhibit angiogenesis. However, it remains unknown whether ATO affects the earliest stages of angiogenesis and vasculogenesis important in tumor development. We purified human monocytes (CD14+) and cultured these cells on collagen I-coated dishes. mCSF was added to the cells after 1 hour of culture. PTN was added twice to the culture, once after 24 hours and again after 5 days with or without ATO or bortezomib. FLK-1 expression (VEGFR-2) showed that the cells incubated on collagen I without drugs formed tube-like structures in the presence of PTN and mCSF. However, the tube-like structures disappeared after adding either the IC50 (5x10−6M) dose or low (5x10−7M) dose of ATO. FLK-1 staining remains in the tube-like structures with low doses (3x10−12M) of bortezomib. In order to examine whether ATO or bortezomib affects endothelial gene expression when monocytes are induced to transdifferentiate in the presence of these cytokines, we also examined expression using RT-PCR on endothelial cell genes (vascular endothelial growth factor receptor-2 (Flk-1), Tie-2 and von Willebrand factor (vWF)) and Western blot analysis for protein expression. The results of both RT-PCR and Western blot analysis showed that the expression of endothelial markers was blocked at both the higher (5x10−6M) and lower (5x10−7M) doses of ATO. In contrast, the expression of endothelial markers was not reduced by adding low dose bortezomib (3x10−12M). We further examined the effects of ATO and bortezomib on early stage angiogenesis in vivo using the chorioallantoic membrane (CAM) assay. Fertilized chick eggs were incubated horizontally at 38°C in a humidified incubator, windowed by day 3 of incubation and processed by day 8. The tested micro-sponge with ATO (5x10−6M) or bortezomib (3x10−11M) or control reagents was implanted on the CAM. The eggs were sealed with adhesive tape and returned to the incubator for 48 hours. The assay scored positive when two independent observers reported a significant reduction of vessels in the treated area. The results of the CAM assay showed that compared to saline, ATO significantly reduced new macroscopic and microscopic vessel formation. In contrast, bortezomib did not affect angiogenesis in the CAM assay. These experiments define a previously unrecognized novel mechanism by which ATO may have anti-angiogenetic effects in cancer patients-preventing the transdifferentiation of monocytes into endothelial cells by PTN. They also suggest ATO as a potential new specific agent to inhibit angiogenesis resulting from transdifferentiation of monocytes into vascular endothelial cells driven by pleiotrophin and mCSF. These results suggest a novel way by which anti-cancer agents may impact angiogenesis.


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