scholarly journals A Novel in vivo Gene Transfer Technique and in vitro Cell Based Assays for the Study of Bone Loss in Musculoskeletal Disorders

Author(s):  
Dennis J. Wu ◽  
Neha Dixit ◽  
Erika Suzuki ◽  
Thanh Nguyen ◽  
Hyun Seock Shin ◽  
...  

2021 ◽  
Vol 12 (7) ◽  
Author(s):  
Ying Liu ◽  
Wenjie Liu ◽  
Ziqiang Yu ◽  
Yan Zhang ◽  
Yinghua Li ◽  
...  

AbstractBromodomain-containing protein 4 (BRD4) has emerged as a promising treatment target for bone-related disorders. (+)-JQ1, a thienotriazolodiazepine compound, has been shown to inhibit pro-osteoclastic activity in a BRD4-dependent approach and impede bone loss caused by ovariectomy (OVX) in vivo. However, clinical trials of (+)-JQ1 are limited because of its poor druggability. In this study, we synthesized a new (+)-JQ1 derivative differing in structure and chirality. One such derivative, (+)-ND, exhibited higher solubility and excellent inhibitory activity against BRD4 compared with its analogue (+)-JQ1. Interestingly, (-)-JQ1 and (-)-ND exhibited low anti-proliferative activity and had no significant inhibitory effect on RANKL-induced osteoclastogenesis as compared with (+)-JQ1 and (+)-ND, suggesting the importance of chirality in the biological activity of compounds. Among these compounds, (+)-ND displayed the most prominent inhibitory effect on RANKL-induced osteoclastogenesis. Moreover, (+)-ND could inhibit osteoclast-specific gene expression, F‐actin ring generation, and bone resorption in vitro and prevent bone loss in OVX mice. Collectively, these findings indicated that (+)-ND represses RANKL‐stimulated osteoclastogenesis and averts OVX-triggered osteoporosis by suppressing MAPK and NF-κB signalling cascades, suggesting that it may be a prospective candidate for osteoporosis treatment.



Antioxidants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 619
Author(s):  
Hyun-Jung Park ◽  
Malihatosadat Gholam-Zadeh ◽  
Sun-Young Yoon ◽  
Jae-Hee Suh ◽  
Hye-Seon Choi

Loss of ovarian function is closely related to estrogen (E2) deficiency, which is responsible for increased osteoclast (OC) differentiation and activity. We aimed to investigate the action mechanism of E2 to decrease bone resorption in OCs to protect from ovariectomy (OVX)-induced bone loss in mice. In vivo, tartrate-resistant acid phosphatase (TRAP) staining in femur and serum carboxy-terminal collagen crosslinks-1 (CTX-1) were analyzed upon E2 injection after OVX in mice. In vitro, OCs were analyzed by TRAP staining, actin ring formation, carboxymethylation, determination of reactive oxygen species (ROS) level, and immunoprecipitation coupled with Western blot. In vivo and in vitro, E2 decreased OC size more dramatically than OC number and Methyl-piperidino-pyrazole hydrate dihydrochloride (MPPD), an estrogen receptor alpha (ERα) antagonist, augmented the OC size. ERα was found in plasma membranes and E2/ERα signaling affected receptor activator of nuclear factor κB ligand (RANKL)-induced actin ring formation by rapidly decreasing a proto-oncogene tyrosine-protein kinase, cellular sarcoma (c-Src) (Y416) phosphorylation in OCs. E2 exposure decreased physical interactions between NADPH oxidase 1 (NOX1) and the oxidized form of c-Src homology 2 (SH2)-containing protein tyrosine phosphatase 2 (SHP2), leading to higher levels of reduced SHP2. ERα formed a complex with the reduced form of SHP2 and c-Src to decrease c-Src activation upon E2 exposure, which blocked a signal for actin ring formation by decreased Vav guanine nucleotide exchange factor 3 (Vav3) (p–Y) and Ras-related C3 botulinum toxin substrate 1 (Rac1) (GTP) activation in OCs. E2/ERα signals consistently inhibited bone resorption in vitro. In conclusion, our study suggests that E2-binding to ERα forms a complex with SHP2/c-Src to attenuate c-Src activation that was induced upon RANKL stimulation in a non-genomic manner, resulting in an impaired actin ring formation and reducing bone resorption.



Blood ◽  
1992 ◽  
Vol 79 (10) ◽  
pp. 2694-2700 ◽  
Author(s):  
DR Rill ◽  
RC Moen ◽  
M Buschle ◽  
C Bartholomew ◽  
NK Foreman ◽  
...  

Abstract Autologous bone marrow transplantation (ABMT) is widely used as treatment for malignant disease. Although the major cause of treatment failure is relapse, it is unknown if this arises entirely because of residual disease in the patient or whether contaminating cells in the rescuing marrow contribute. Attempts to purge marrow of its putative residual malignant cells may delay hematopoietic reconstitution and are of uncertain efficacy. We now describe how retrovirus-mediated gene transfer may be used to elucidate the source of relapse after ABMT for acute myeloid leukemia and to evaluate the efficacy of purging. Clonogenic myeloid leukemic blast cells in patient marrow can be transduced with the NeoR gene-containing helper-free retrovirus, LNL6, with an efficacy of 0% to 23.5% (mean, 10.5%). Transduced colonies grow in selective media and the presence of the marker gene can be confirmed in individual malignant colonies by polymerase chain reaction. If such malignant cells remain in harvested “remission” marrow, they will therefore be marked after exposure to LNL6. Detection of the marker gene in the malignant cells present at any later relapse would be firm evidence that residual disease contributed to disease recurrence, and would permit rapid subsequent evaluation of purging techniques. The technique also marks normal marrow progenitors from patients with acute myeloblastic leukemia. These colony-forming cells can be detected in long-term marrow cultures at a frequency of 1% to 18% for up to 10 weeks after exposure to the vector. Animal models and analysis of probability tables both suggest that these levels of marking in vitro are sufficient to provide information about the mechanisms of relapse and the biology of marrow regeneration in vivo. These preclinical data form part of the basis for current clinical studies of gene transfer into marrow before ABMT.



Blood ◽  
1996 ◽  
Vol 87 (7) ◽  
pp. 2723-2731 ◽  
Author(s):  
P Schwarzenberger ◽  
S Spence ◽  
N Lohrey ◽  
T Kmiecik ◽  
DL Longo ◽  
...  

To develop a rapid preclinical in vivo model to study gene transfer into human hematopoietic progenitor cells, MO-7e cells (CD-34+, c-kit+) were infected with multidrug resistance (MDR1)-containing retroviruses and then transplanted into nonobese diabetic severe combined immunodeficient mice (NOD SCID). MO-7e cells infected with a retrovirus encoding the human MDR1 cDNA showed integration, transcription, and expression of the transfered MDR1 gene. This resulted in a 20-fold increase in the resistance of MO-7e cells to paclitaxel in vitro. The expression of the MDR1 gene product was stable over a 6-month period in vitro without selection in colchicine. MO-7e and MDR1-infected MO-7e cells were transplanted into NOD SCID mice to determine whether MDR1 could confer drug resistance in vivo. A sensitive polymerase chain reaction method specific for human sequences was developed to quantitate the level of human cell engraftment in NOD SCID bone marrow (BM) cells. The percentage of human DNA in BM cells from MO-7e- transplanted mice was 10.9% and decreased to 0.7% in mice treated with paclitaxel. The percentage of human DNA in infected-MO-7e transplanted mice was 7.6% and that level was unchanged in mice treated with paclitaxel. These results show that expression of the MDR1 gene in human hematopoietic progenitor cells can confer functional drug resistance in an in vivo model.



2000 ◽  
Vol 57 (8) ◽  
pp. 1326-1333 ◽  
Author(s):  
I. Hellgren* ◽  
V. Drvota ◽  
R. Pieper ◽  
S. Enoksson ◽  
P. Blomberg ◽  
...  




Stroke ◽  
2012 ◽  
Vol 43 (suppl_1) ◽  
Author(s):  
Rong Xie ◽  
Michelle Cheng ◽  
Mei Li ◽  
Robert Sapolsky ◽  
Heng Zhao

Background and Objective: Akt is a serine-threonine kinase that plays critical role in promoting cell survival. Akt consists of three isoforms (Akt1, 2, 3), with Akt3 predominantly expressed in the brain. Although Akt pathway has been shown to mediate neuronal survival in cerebral ischemic injury, it is unclear how these Akt isoforms contribute to neuronal protection, and whether exogenous Akt can protect the brain against ischemic injury or not. In this study, we over-expressed Akt isoforms and its downstream signaling proteins such as FKHR and PRAS40 to investigate the role of the Akt pathway along with its potential relationship with the mTOR pathway in stroke. Methods: Sprauge Dawley rats (250∼280g) were used for all studies. A lentiviral vector consists of a CMV promoter driving IRES-eGFP was used to clone an active Akt 1 and 3 (cAKt 1 and 3), dominant-negative Akt (AktDN), active FKHR (AAA FKHR), and PRAS40. Lentivirus expressing these genes were added to primary mixed cortical cultures for two days prior to oxygen glucose deprivation (OGD) (MOI=1:5). Neuronal survival was measured by LDH release. Lentivirus were stereotaxically injected into the cortex, and rats were subjected to focal ischemia induced by distal MCA occlusion combined with bilateral CCA occlusion. Western blotting and immunofluorescent confocal microscopy were used to detect the expression of Akt isoforms and other proteins in both the Akt and mTOR pathways. Results: Western blotting analysis showed that both endogenous Akt1 and 3 proteins degraded as early as 1 h after stroke, while Akt2 protein remained unchanged until 24 h after stroke. In vitro studies showed that over-expression of both constitutively active cAkt1 and cAkt3 decreased LDH release after OGD, while AktDN worsened neuronal death ( P <0.05). In vivo over-expression of cAkt1, cAkt3 and PRAS40 reduced infarct size after stroke ( P <0.01). Gene transfer of cAkt1 and 3 also promoted protein levels of pAkt (phosphorylated Akt), pPRAS40, pFKHR, pPTEN, pmTOR, but not pGSK3β. Both in vitro and in vivo studies showed that over-expression of cAkt3 resulted in a stronger protection than cAkt1 ( P <0.05). Interestingly, cAkt3 gene transfer preserved both endogenous protein levels of Akt1 and 3, whereas cAkt1 gene transfer only preserved endogenous Akt1. Furthermore, cAkt3 promoted higher pmTOR levels than cAkt1. Treatment of rapamycin, an mTOR inhibitor, blocked the protective effects of both cAkt1 and cAkt3 both in vitro and in vivo. Conclusion: Lentiviral-mediated overexpression of cAkt3 confers stronger protection than that of cAkt1, by maintaining both endogenous Akt1 and Akt3, as well as promoting higher mTOR activities after stroke.



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