As a subclass of noncoding RNAs, circular RNAs (circRNAs) have been demonstrated to play a critical role in regulating gene expression in eukaryotes. Recent studies have revealed the pivotal ...functions of circRNAs in cancer progression. However, little is known about the role of circTADA2A, also named hsa_circ_0043278, in osteosarcoma (OS).
CircTADA2A was selected from a previously reported circRNA microarray comparing OS cell lines and normal bone cells. QRT-PCR was used to detect the expression of circTADA2A in OS tissue and cell lines. Luciferase reporter, RNA immunoprecipitation (RIP), RNA pull-down and fluorescence in situ hybridization (FISH) assays were performed to confirm the binding of circTADA2A with miR-203a-3p. OS cells were stably transfected with lentiviruses, and Transwell migration, Matrigel invasion, colony formation, proliferation, apoptosis, Western blotting, and in vivo tumorigenesis and metastasis assays were employed to evaluate the roles of circTADA2A, miR-203a-3p and CREB3.
Our findings demonstrated that circTADA2A was highly expressed in both OS tissue and cell lines, and circTADA2A inhibition attenuated the migration, invasion and proliferation of OS cells in vitro as well as tumorigenesis and metastasis in vivo. A mechanistic study revealed that circTADA2A could readily sponge miR-203a-3p to upregulate the expression of CREB3, which was identified as a driver gene in OS. Furthermore, miR-203a-3p inhibition or CREB3 overexpression could reverse the circTADA2A silencing-induced impairment of malignant tumor behavior.
CircTADA2A functions as a tumor promoter in OS to increase malignant tumor behavior through the miR-203a-3p/CREB3 axis, which could be a novel target for OS therapy.
Structural damping is the most important characteristic for evaluating the vibration suppression performance of engineering structures. This paper proposes a dynamic topology optimization method for ...designing a composite macrostructure containing a multiphase viscoelastic composite material microstructure layer. The method optimizes the macrostructure damping performance, which is indicated by the modal loss factor, in the multiphase microstructural configuration design process. The damping layer is assumed to be constructed from a viscoelastic composite material, and viscoelastic composite material microstructures are composed of a high-stiffness material and a high-damping material. The effective properties of the viscoelastic composites were homogenized and integrated into the macrostructure analysis. Design variables were assigned for each microstructure to implement topology optimization on each viscoelastic material microstructure. Sensitivity analysis was performed to compute the derivatives of structural damping with respect to each design variable. Several numerical examples were conducted to demonstrate the effectiveness of the proposed approach. Various optimized structures were obtained using varying objectives and volume fractions. The numerical example results show that the proposed method is effective for designing a composite structure with multiphase viscoelastic composite materials for maximizing the modal loss factor. The structural vibration performance of the optimal composite structure was significantly improved.
This paper proposes a novel density-based concurrent topology optimization method to support the two-scale design of composite plates for vibration mitigation. To have exceptional damping ...performance, dynamic compliance of the composite plate is taken as the objective function. The complex stiffness model is used to describe the material damping and accurately consider the variation of structural response due to the change of damping composite material configurations. The mode superposition method is used to calculate the complex frequency response of the composite plates to reduce the heavy computational burden caused by a large number of sample points in the frequency range during each iteration. Both microstructural configurations and macroscopic distribution are optimized in an integrated manner. At the microscale, the damping layer consists of periodic composites with distinct damping and stiffness. The effective properties of the periodic composites are homogenized and then are fed into the complex frequency response analysis at the macroscale. To implement the concurrent topology optimization at two different scales, the design variables are assigned for both macro- and micro-scales. The adjoint sensitivity analysis is presented to compute the derivatives of dynamic compliance of composite plates with respect to the micro and macro design variables. Several numerical examples with different excitation inputs and boundary conditions are presented to confirm the validity of the proposed methodologies. This paper represents a first step towards designing two-scale composite plates with optional dynamic performance under harmonic loading using an inverse design method.
Study Design:
A retrospective study of prospectively collected radiographic and clinical data.
Objective:
This study aims to investigate the relationship between endplate morphology parameters and ...the incidence of cage subsidence in patients with mini-open single-level oblique lateral lumbar interbody fusion (OLIF).
Methods:
We included 119 inpatients who underwent OLIF from February 2015 to December 2017. A total of 119 patients with single treatment level of OLIF were included. Plain anteroposterior and lateral radiograph were taken preoperatively, postoperatively, and during follow-up. The correlation between disc height, endplate concave angle/depth, cage position and cage subsidence were investigated. Functional rating index (Visual Analogue Scale for pain, and Roland Morris Disability Questionnaire) were employed to assess clinical outcomes.
Results:
Cage subsidence was more commonly seen at the superior endplates (42/119, 35.29%) than at the inferior endplates (6/119, 5.04%) (p < 0.01). More importantly, cage subsidence was significantly less in patients with superior endplates that were without concave angle (3/20, 15%) than with concave angle (37/99, 37.37%) (p < 0.05). Cage subsidence correlated negatively with preoperative anterior disc height (r = −0.21, p < 0.05), but positively with disc distraction rate (r = 0.27, p < 0.01). Lastly, the distance of cage to the anterior edges of the vertebral body showed a positive correlation (r = 0.26, p < 0.01).
Conclusions:
This study for the first time demonstrated that endplate morphology correlates with cage subsidence after OLIF. Since relatively flat endplates with smaller concave angle significantly diminish the incidence of subsidence, the morphology of cage surface should be taken into consideration when designing the next generation of cage. In addition, precise measurement of the disc height to avoid over-distraction, and more anteriorly placement of the cage is suggested to reduce subsidence.
Cartilage homeostasis is essential for chondrocytes to maintain proper phenotype and metabolism. Because adult articular cartilage is avascular, chondrocytes must survive in low oxygen conditions, ...and changing oxygen tension can significantly affect metabolism and proteoglycan synthesis in these cells. However, whether long noncoding RNA participate in cartilage homeostasis under hypoxia has not been reported yet. Here, we first identified LncZFHX2 as a lncRNA upregulated under physiological hypoxia in cartilage, specifically by HIF‐1α. LncZFHX2 knockdown simultaneously accelerated cellular senescence, targeted multiple components of extracellular matrix metabolism, and increased DNA damage in chondrocytes. Through a series of in vitro and in vivo experiments, we identified that LncZFHX2 performed a novel function that regulated RIF1 expression through forming a transcription complex with KLF4 and promoting chondrocyte DNA repair. Moreover, chondrocyte-conditional knockout of LncZFHX2 accelerated injury-induced cartilage degeneration in vivo. In conclusion, we identified a hypoxia-activated DNA repair pathway that maintains matrix homeostasis in osteoarthritis cartilage.
Background
Circular RNAs (circRNAs) have risen to prominence as important regulators of biological processes. This study investigated whether circGNB1 functions as a competitive endogenous RNA to ...regulate the pathological process of oxidative stress in age‐related osteoarthritis (OA).
Methods
The relationship between circGNB1 expression and oxidative stress/OA severity was determined in cartilages from OA patients at different ages. The biological roles of circGNB1 in oxidative stress and OA progression, and its downstream targets were determined using gain‐ and loss‐of‐function experiments in various biochemical assays in human chondrocytes (HCs). The in vivo effects of circGNB1 overexpression and knockdown were also determined using a destabilization of the medial meniscus (DMM) mouse model.
Results
Increased circGNB1 expression was detected in HCs under oxidative and inflammatory stress and in the cartilage of older individuals. Mechanistically, circGNB1 sponged miR‐152‐3p and thus blocked its interaction with its downstream mRNA target, ring finger protein 219 (RNF219), which in turn stabilized caveolin‐1 (CAV1) by preventing its ubiquitination at the K47 residue. CircGNB1 inhibited IL‐10 signalling by antagonizing miR‐152‐3p‐mediated RNF219 and CAV1 inhibition. Consequently, circGNB1 overexpression promoted OA progression by enhancing catabolic factor expression and oxidative stress and by suppressing anabolic genes in vitro and in vivo. Furthermore, circGNB1 knockdown alleviated the severity of OA, whereas circGNB1 overexpression had the opposite effect in a DMM mouse model of OA.
Conclusion
CircGNB1 regulated oxidative stress and OA progression via the miR‐152‐3p/RNF219/CAV1 axis. Modulating circGNB1 could be an effective strategy for treating OA.
CircGNB1 sponges miR‐152‐3p and up‐regulates the expression of RNF219.
RNF219 binds to CAV1.
CircGNB1/miR‐152‐3p/RNF219 axis negatively regulates the degradation of CAV1 protein by inhibiting its ubiquitination.
CircGNB1/miR‐152‐3p/RNF219/CAV1 axis plays a significant role in OA through IL‐10 signalling pathway.
Intervertebral disk degeneration (IVDD) is a spinal disk condition caused by an inflammatory response induced by various proinflammatory cytokines, such as interleukin (IL)-1β and tumor necrosis ...factor (TNF)-α. cyclin-dependent kinase 9 (CDK9) is a transcriptional regulator and potential therapeutic target for many diseases, especially in regulating the activation of primary inflammatory response genes. Our study investigated a highly selective CDK9 inhibitor, atuveciclib, which protects nucleus pulposus (NP) cells from proinflammatory stimuli-induced catabolism. The effects of CDK9 inhibition were determined in human and rat NP cells treated with IL-1β in the presence or absence of atuveciclib or small interfering RNA target CDK9. Inhibition of CDK9 led to the attenuation of inflammatory response. In addition, rat intervertebral disk (IVD) explants were used to determine the role of CDK9 inhibition in extracellular matrix degradation. The rat IVDD model also proved that CDK9 inhibition attenuated IVDD, as validated using magnetic resonance imaging and immunohistochemistry. Taken together, CDK9 is a potential therapeutic target to prevent IVDD.
Circular RNAs (circRNA) expression aberration has been identified in various human diseases. In this study, we investigated whether circRNAs could act as competing endogenous RNAs to regulate the ...pathological process of osteoarthritis (OA).
CircRNA deep sequencing was performed to the expression of circRNAs between OA and control cartilage tissues. The regulatory and functional role of CircSERPINE2 upregulation was examined in OA and was validated in vitro and in vivo, downstream target of CircSERPINE2 was explored. RNA pull down, a luciferase reporter assay, biotin-coupled microRNA capture and fluorescence in situ hybridisation were used to evaluate the interaction between CircSERPINE2 and miR-1271-5 p, as well as the target mRNA, E26 transformation-specific-related gene (ERG). The role and mechanism of CircSERPINE2 in OA was also explored in rabbit models.
The decreased expression of CircSERPINE2 in the OA cartilage tissues was directly associated with excessive apoptosis and imbalance between anabolic and catabolic factors of extracellular matrix (ECM). Mechanistically, CircSERPINE2 acted as a sponge of miR-1271-5 p and functioned in human chondrocytes (HCs) through targeting miR-1271-5 p and ERG. Intra-articular injection of adeno-associated virus-CircSERPINE2-wt alleviated OA in the rabbit model.
Our results reveal an important role for a novel circRNA-CircSERPINE2 in OA progression. CircSERPINE2 overexpression could alleviate HCs apoptosis and promote anabolism of ECM through miR-1271-ERG pathway. It provides a potentially effective therapeutic strategy for OA progression.
•Topology optimization for designing high broadband damping composite material.•Two competitive frequency-dependent damping materials are adopted in microstructure.•Optimal results with clear ...topology are obtained by K-S or weighted objective function.•Different connected phase damping material shows different damping properties.
The optimization of damping composite material in a certain frequency range has become one of the critical issues in structural engineering applications due to the fact that the structures usually work in a wide vibration frequency range. This paper proposes a topology optimization method for designing the damping composite materials with high stiffness and high broadband damping. The broadband damping composite material is realized by the properly combing two phases of damping material, in which phase 1 has high loss factor in lower frequency range and phase 2 has high loss factor in higher frequency range. In order to maximize the material damping performance in a given frequency range, we suggest a new algorithm for finding the optimal two-phase damping materials layout in micro scales, while the homogenized effective complex elastic matrix is obtained by considering the two damping materials layout in the microstructure. The mathematical model with two different objective functions, which are K-S objective function and weighted objective function, has been established. The first is maximize the minimum material loss factor in the given frequency range and the second is maximize the sum of the material loss factor in the given frequency range. Several typical numerical examples are presented to demonstrate the effectiveness of the proposed optimization method. An in-depth analysis is conducted to reveal the effects of the weighting factor on the optimal solutions. The results show that the K-S function has the ability to maximize the minimum damping of composite material in the given frequency band. The material loss factor increases with the increase of weighting factor. All of the results show that the proposed method can get the optimal microstructure with clearly material layout, no matter the objective is K-S function or weighted function is used.
Osteoarthritis (OA) is a common, age-related, and painful disease characterized by cartilage destruction, osteophyte formation, and synovial hyperplasia. This study revealed that circPDE4D, a ...circular RNA derived from human linear PDE4D, plays a critical role in maintaining the extracellular cellular matrix (ECM) during OA progression. circPDE4D was significantly downregulated in OA cartilage tissues and during stimulation with inflammatory cytokines. The knockdown of circPDE4D predominantly contributed to Aggrecan loss and the upregulation of matrix catabolic enzymes, including MMP3, MMP13, ADAMTS4, and ADAMTS5, but not proliferation or apoptosis. In a murine model of destabilization of the medial meniscus (DMM), the intraarticular injection of circPDE4D alleviated DMM-induced cartilage impairments. Mechanistically, we found that circPDE4D exerted its effect by acting as a sponge for miR-103a-3p and thereby regulated FGF18 expression, which is a direct target of miR-103a-3p. In conclusion, our findings highlight a novel protective role of circPDE4D in OA pathogenesis and indicate that the targeting of the circPDE4D-miR-103a-3p-FGF18 axis might provide a potential and promising approach for OA therapy.
Display omitted
Osteoarthritis (OA) is an age-related disease characterized by cartilage destruction, osteophyte formation, and synovial hyperplasia. Shen and colleagues identified a novel circPDE4D playing a protective role against cartilage degeneration during OA progression, which might shed a new light on the prevention and treatment of OA.
PDF
