Endorepellin downregulation promotes angiogenesis after experimental traumatic brain injury

Endorepellin plays a key role in the regulation of angiogenesis,but its effects on angiogenesis after traumatic brain injury are unclear.This study explored the effects of endorepellin on angiogenesis and neurobehavioral outcomes after traumatic brain injury in mice.Mice were randomly divided into four groups:sham,controlled cortical impact only,adeno-associated virus(AAV)-green fluorescent protein,and AAV-shEndorepellin-green fluorescent protein groups.In the controlled cortical impact model,the transduction of AAV-shEndorepellin-green fluorescent protein downregulated endorepellin while increasing the number of CD31+/Ki-67+proliferating endothelial cells and the functional microvessel density in mouse brain.These changes resulted in improved neurological function compared with controlled cortical impact mice.Western blotting revealed increased expression of vascular endothelial growth factor and angiopoietin-1 in mice treated with AAV-shEndorepellin-green fluorescent protein.Synchrotron radiation angiography showed that endorepellin downregulation promoted angiogenesis and increased cortical neovascularization,which may further improve neurobehavioral outcomes.Furthermore,an in vitro study showed that downregulation of endorepellin increased tube formation by human umbilical vein endothelial cells compared with a control.Mechanistic analysis found that endorepellin downregulation may mediate angiogenesis by activating vascular endothelial growth factor-and angiopoietin-1-related signaling pathways.

Microtopography Attenuates Endothelial Cell Proliferation by Regulating MicroRNAs

Endothelial cell (EC) morphology can be regulated by the micro/nano topography in engineered vascular grafts and by hemodynamic forces in the native blood vessels. However, how EC morphology affects miRNA and thus EC functions is not well understood. In this study, we addressed this question by using human umbilical vein endothelial cells (HUVECs) cultured on microgrooves as a model. HUVECs were grown on either microgrooved (with 10 μm width/spacing and 3 μm depth) or smooth surfaces. HUVECs on microgrooved surface had elongated and bipolar morphology, while HUVECs on smooth surface showed cobble stone shape or non-polar morphology. EdU staining indicated that HUVECs with elongated morphology had lower proliferation rate compared to their counterpart cultured on smooth surface. Quantitative PCR analysis demonstrated that the expression of the specific microRNAs (miR-10a, miR-19a, miR-221) that targeted proliferation-related genes was all up-regulated. Consistently, the mRNA levels of their respective target genes, mitogen-activated protein kinase kinase kinase 7, Cyclin D1 and c-kit were significantly reduced by a fold change of 0.12 ± 0.01 (p < 0.01), 0.70 ± 0.23 (p 0.05) and 0.76 ± 0.21 (p < 0.05). Other miRNAs such as miR-126 and miR-181a were up-regulated as well, leading to the repression of their targets vascular cell adhesion molecule-1 and prospero homeobox-1. Our results suggested that microgrooved surface may regulate microRNA levels and thus EC functions. These results provide insight into the modulation of EC functions by microtopographic cues, and will facilitate the rational design of microstructured materials for cell and tissue engineering.

Functionalized Asymmetric Poly (Lactic Acid)/Gelatin Composite Membrane for Guided Periodontal Tissue Regeneration

Aim: Periodontitis is caused by chronic gingival inflammation and affects a large population in the world. Although guided tissue regeneration (GTR) therapy has been proven to be an effective treatment, the deficiency in the symmetrical design of all the GTR membrane in the market leaves large space for improvement. Therefore, we designed a novel asymmetrical bi-layer PLA/gelatin composite membrane for treating periodontitis. Methods: The PLA side was fabricated by electrospinning with metronidazole (MNA) pre-mixed with the PLA solution. The gelatin side containing bioglass (BG) 45S5 was fabricated with freeze-drying process and cross-linked with PLA membrane. The bio-compatibility of the membrane was evaluated in vitro using NIH3T3 cells. The releasing of MNA was measured by spectrophotometer. The bioactivity of the membrane was evaluated by hydroxyapatite (HA) deposit and determined by FTIR spectrometer. The ionic concentration of Ca2+ and was measured by ICPOES. The expression of the osteogenesis makers was determined by qRT-PCR. Results: The bi-layer PLA/gelatin composite membrane is biocompatible and bioactive. The releasing of MNA can rapidly reach the anti-bacterial effective concentration. Interestingly, the incorporation of MNA modulated the degradation rate of PLA scaffold to meet the requirement of tissue regeneration. Meanwhile, the embedding of the BG powder in the gelatin porous layer provided a favorable Ca2+ and ion environment for the regeneration of the alveolar bone tissue. Conclusions: Taken together, this bi-layer GTR membrane is closer to the physiological structure of the periodontal. The addition of MNA and BG makes it more powerful in treating periodontitis. Moreover, this research provides an example of biomimetic design in fabricating biomaterial for clinical applications.

Biomaterial Surface Can Modify HUVEC Morphology and Inflammatory Response by Regulating MicroRNA Expression

Vascular inflammation is an important process which contributes to the pathogenesis of many cardiovascular diseases, such as atherosclerosis. MicroRNAs (miRNAs) have been revealed as novel regulators of vascular inflammation. Prior researches had shown that alterations in gene expression of human umbilical vein endothelial cells (HUVECs) associated with topo-graphic cues. Here, we showed that poly (dimethyl siloxane) (PDMS) substrate of 10 μm width and 3 μm depth parallel microgrooves on the surface could significantly upregulate the expression of anti-inflammatory microRNAs, miR-146a and miR-181b. In addition, the results also showed that TRAF6 and importin-α3, target of miR-146a and miR-181b, respectively, were both down-regulated (P < 0.05 and P < 0.001, respectively). The expression levels of the inflammation related proteins were all significantly decreased, including VCAM-1 (P < 0.05), ICAM-1 (P < 0.001), E-selectin (P < 0.001), and MCP-1 (P < 0.05). The adhesion of the mononuclear cell line, THP-1, was significantly decreased (P < 0.05). The results revealed that morphology modified HUVEC can modulate miR-146a and miR-181b and their downstream biological functions such as decreasing inflammation, suggesting that surface microtopology may affect vascular inflammation in the setting of cardiovascular disease. These interesting findings will facilitate the optimal design of microstructured materials in tissue engineering.

Cell Morphology Modified by Biomaterial Induces miR-21 Expression and Apoptosis

Biochemical factors can play an important role in regulating gene expression in human umbilical vein endothelial cells (HUVECs), yet the role of biophysical factors during this process is unknown. Here, we show that physical cues, in the form of parallel microgrooves on the surface of cell adhesive substrates, can change the morphology of HUVECs as well as specific microRNA expression. Cells cultured on microgrooved poly (dimethyl siloxane) (PDMS) surface exhibited a more elongated morphology relative to those cultured on flat surfaces, and favored outgrowth along the axis of groove alignment. The level of microRNAs in the cell was screened by miRNA microchip and verified by qRT-PCR. The result showed that around 26 microRNAs have been modified significantly, among which miR-21 level was dramatically elevated. Western-blotting analysis demonstrated that PTEN, a target of miR- 21, was up-regulated in HUVECs with elongated morphology. Cell apoptosis level was significantly decreased, with was associated with the increasing of miR-21 level. These results suggested that biophysical factors can directly modify HUVECs morphology, thus induce miR-21 expression in HUVECs and its downstream biological functions such as decreasing apoptosis. This study provided evidence that surface microtopology should also be considered in designing biomaterials in tissue engineering application.

Inhibition of SIRT6 in prostate cancer reduces cell viability and increases sensitivity to chemotherapeutics

SI RT6 is an important histone modifying protein that regulates DNA repair,telomere maintenance,energy me-tabolism,and target gene expression.Recently SIRT6 has been identifi ed as a tumor suppressor and is down-regulated in certain cancer types,but not in other can-cers.From deposited gene profi ling studies we found that SIRT6 was overexpressed in prostate tumors,compared with normal or paratumor prostate tissues.Tissue micro-array studies confi rmed the higher levels of SIRT6 in both prostate tumor tissues and prostate cancer cells than in their normal counterparts.Knockdown of SIRT6 in human prostate cancer cells led to sub-G1 phase arrest of cell cy-cle,increased apoptosis,elevated DNA damage level and decrease in BCL2 gene expression.Moreover,SIRT6-de-fi ciency reduced cell viability and enhanced chemothera-peutics sensitivity.Taken together,this study provides the fi rst evidence of SIRT6 overexpression in human prostate cancer,and SIRT6 regulation could be exploited for pros-tate cancer therapy.

Development and Characterization of Nanobody-Derived CD47 Theranostic Pairs in Solid Tumors

Overexpression of CD47 is frequently observed in various types of human malignancies,inhibiting myeloidmediated elimination of tumor cells and affecting the prognosis of cancer patients.By mapping biomarker expression,immuno-positron emission tomography has been increasingly used for patient screening and response monitoring.By immunization alpacas with recombinant human CD47,we prepared a CD47-targeting nanobody C2 and developed[^(68)Ga]Ga-NOTA-C2,followed by an exploration of the diagnostic value in CD47-expressing tumor models including gastric-cancer patient-derived xenograft models.By fusing C2 to an albumin binding domain(ABD),we synthesized ABDC2,which had increased in vivo half-life and improved targeting properties.We further labeled ABDC2 with^(68)Ga/^(89)Zr/177Lu to develop radionuclide theranostic pairs and evaluated the pharmacokinetics and theranostic efficacies of the agents in cell-and patient-derived models.Both C2 and ABDC2 specifically reacted with human CD47 with a high KD value of 23.50 and 84.57 pM,respectively.[^(68)Ga]Ga-NOTA-C2 was developed with high radiochemical purity(99>%,n=4)and visualized CD47 expression in the tumors.In comparison to the rapid renal clearance and short half-life of[^(68)Ga]Ga-NOTA-C2,both[^(68)Ga]Ga-NOTA-ABDC2 and[^(89)Zr]Zr-DFOABDC2 showed prolonged circulation and increased tumor uptake,with the highest uptake of[^(89)Zr]Zr-DFO-ABDC2 occurring at 72 h post-injection.Moreover,[177Lu]Lu-DOTA-ABDC2 radioimmunotherapy suppressed the tumor growth but was associated with toxicity,warranting further optimization of the treatment schedules.Taken together,we reported a series of nanobody-derived CD47-targeted agents,of which[^(68)Ga]Ga-NOTA-C2 and[^(89)Zr]Zr-DFO-ABDC2 are readily translatable.Optimization and translation of CD47-targeted theranostic pair may provide new prospects for CD47-targeted management of solid tumors.

Effect of Attachment on Movement Control of the Central Incisor Using Invisible Orthodontics:In-Silico Finite Element Analysis

We aimed to study the influence of attachment on central incisor movement control using invisible orthodontics with different translation or rotation targets.In this study,cone-beam computerised tomography was used to scan one 15-year-old volunteer’s teeth.Three-dimensional models of the mandibular central incisor,removable orthodontic appliance,and a rectangular attachment were reconstructed.A non-linear finite element simulation was used to analyse the influence of attachment on the stress distribution of the periodontal ligament of the central incisor under tooth rotation,mesial translation,and labial-lingual translation.For mandibular central incisor correction,using rectangular attachments increased the translation by up to 9.6%,increased the maximum stress on the periodontal ligament during the mesial translation correction,and reduced unwanted labial-lingual tilt by up to 40%during the rotation of the tooth.However,wearing an attachment during labial-lingual translation had no significant effect on the orthodontic results of the mandibular central incisor.In the mandibular central incisor’s invisible orthodontic,the rectangular attachment appliance increased the displacement and alleviated the side effect after applying mesial translation and tooth rotation.For labial-lingual translation,the application of a rectangular attachment had no pronounced effect on the results.

Digital light processing (DLP)-based (bio)printing strategies for tissue modeling and regeneration

Digital light processing(DLP)-based bioprinting technology has recently aroused considerable concerns as a strategy to deliver biomedical materials and/or specific cells to create sophisticated structures for various tissue modeling and regeneration.In this review,we display a concise introduction of DLP bioprinting,and a further discussion on the design and manufacture of DLP(bio)printer with varied bioinks and their biomedical applications toward drug screening,disease modeling,tissue repair,and regenerative medicine.Finally,the advantages,challenges,and perspectives of the DLP printing platforms are detailed.It is believed that DLP bioprinting will play a decisive role in the field of tissue model and regenerative medicine,mainly due to its time-efficient,higher resolution,and amenability to automation for various tissue needs.

Modeling of the fibrin agarose plate assay and its application for thrombolytic analysis

The fibrin agarose plate assay is widely used in the detection of thrombolysis efficacy. However, a rigorous mathematical model for analyzing data or comparing activities of different thrombolytics has been absent. This study investigated the relationship between thrombolysis radius, R, and diffusion time, t, of molecular medicines in an agarose hydrogel system by deriving a model based on Fick's law and experimental verification by the fibrin agarose plate assay method. The theoretical results showed that a plot of log(R) versus log(t) has a linear curve with the slope of 1/2 and this was verified by experimental results using urokinase as a modeling agent. Moreover, it was found that R÷t is constant for a specific thrombolytic and can be used as a parameter for evaluating activities of different thrombolytics. The theoretical model has potential for improving the understanding of mecha-nisms involved in molecular medicine diffusion and offers benefits for thrombolytic therapy.

An Improved Phase Retrieval Algorithm for X-ray In-line Phase-Contrast Imaging

Phase contrast imaging technique has been improved promptly in recent years. Among these techniques in-line phase-contrast imaging is widely used. Various algorithms for in-line phase retrieval have been proposed so far such as TIE(transport of intensity equation), CTF(contrast transfer function), first born-approximations, GSF(Gerchberg-Saxton-Fienup), etc. Bronnikov's algorithm(BA) is a type of linear algorithm that is simple and efficient. But it can only be used without absorption situations. In this paper, an improved algorithm based on BA was presented. The approach adds Δφ(x,y) to the phase map φ_b(x,y) retrieved by BA to make the reconstructed phase map more precise. Further, the approach was evaluated on simulated images and confirmed to be accurate at higher absorption rates.

Design of the Control System for Thermal Treatment via Fuzzy Logic PID

In this paper, a cryosurgery-hyperthermia system is proposed for taking advantage of the alternated cooling and heating treatment in tumor. A novel control system is proposed to ensure that the thermal system works effectively. Firstly,the tissue temperature around the probe is regulated and kept in a desired range when radio frequency ablation is operated. Secondly, precise control of temperature is achieved in hyperthermia treatment using fuzzy logic PID type controller. The results of ex vivo liver experiment demonstrate that this system could provide a rather good performance with the proposed control method.