Hypoxia promotes red blood cell (RBC) sickling, oxidative stress, systemic endothelium activation, vascular inflammation, and activation of coagulation in sickle cell disease (SCD), which results in ...a malicious cycle contributing to the progression of vaso-occlusion and other consequent clinical manifestations, such as acute chest syndrome and ischemic injuries. In the multistep and multicellular paradigm of vaso-occlusion, recruitment of neutrophils and adhesion of sickle RBCs to activated endothelial cells are critical in initiating this cascade of events. To better understand the role of hypoxia in this pathophysiological process, we assessed the adhesion profiles of RBCs and neutrophils to immobilized e-selectin utilizing blood samples from a clinically diverse patient population with SCD.
Blood samples were collected from 11 subjects with homozygous SCD (HbSS) and 5 normal subjects (HbAA). Prior to the experiments, whole blood samples were mixed with Hank's balanced salt buffer solution modified with calcium and magnesium (1:1 v/v). A total volume of 25 µl blood sample was perfused through each e-selectin immobilized microchannel under both normoxic and hypoxic (7.5% oxygen level) conditions using SCD Biochip microfluidic adhesion assay 1, 2. Blood perfusion was followed by a rinse with Hank's buffer solution at 1 dyne/cm2 corresponding to the typical shear stress levels observed in post-capillary venules. Thereafter, neutrophil adhesion, neutrophil rolling, neutrophil-platelet aggregation, and RBC adhesion data were obtained and analyzed.
E-selectin functionalized microchannels supported neutrophil adhesion as well as neutrophil rolling when flowing normal blood samples, where we observed higher adhesion and rolling rates in hypoxia (Fig. 1A). SCD subjects were categorized into two distinct groups based on their adhesion profiles: Group 1: hypoxia-enhanced neutrophil adhesion without significant RBC adhesion (N=7), and Group 2: hypoxia-reduced RBC adhesion with marginal neutrophil adhesion (N=4) (Fig. 1B). We find that both normal and SCD neutrophil adhesion to e-selectin is significantly enhanced under hypoxic conditions (Fig. 1C, p<0.05, paired t-test). Moreover, we observed significantly increased neutrophil-platelet aggregates and an increase in the percentage of adhered neutrophils involved in neutrophil-platelet aggregation induced by hypoxia (Fig. 1D&E), suggesting that hypoxia is strongly associated with neutrophil-platelet aggregation driven vaso-occlusive events in Group 1. Furthermore, rolling velocity of 20 neutrophils from each SCD subjects under shear stress was measured, and hypoxia-mediated neutrophil rolling behavior was determined (Fig. 1F). A unique adhesion profile was observed in Group 2, in which the number of adhered RBCs was significantly reduced in response to hypoxia (Fig. 1G, p<0.05, Mann-Whitney non-parametric analysis).
Here, we report two different adhesion profiles among SCD sub-populations using an e-selectin functionalized microfluidic model. We observed elevated numbers of adherent neutrophils, decreased neutrophil rolling velocities, and enhanced neutrophil-platelet aggregation induced by hypoxia in one group, while lowered number of adhered RBCs mediated by hypoxia in the other group. We speculate that there may be two distinct mechanisms that initiate vaso-occlusive events in SCD: in Group 1, neutrophils are responsive to endothelial activation. In this group, neutrophil recruitment and the resulting neutrophil-platelet aggregates and other complexes may precipitate vaso-ooclusion, which is strongly susceptible to hypoxia. In Group 2, in whom neutrophil recruitment is less effective, vaso-occlusion may be induced by vascular RBC adhesion, in which hypoxia may be a less proximate trigger.
References:Alapan, Y., C. Kim, A. Adhikari, K.E. Gray, E. Gurkan-Cavusoglu, J.A. Little, and U.A. Gurkan, Sickle cell disease biochip: a functional red blood cell adhesion assay for monitoring sickle cell disease. Transl Res, 2016. 173: p. 74-91.e8.Kim, M., Y. Alapan, A. Adhikari, J.A. Little, and U.A. Gurkan, Hypoxia-enhanced adhesion of red blood cells in microscale flow. Microcirculation, 2017. 24(5).
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Little:NHLBI: Research Funding; Hemex: Patents & Royalties: Patent, no honoraria; PCORI: Research Funding; Doris Duke Charitable Foundations: Research Funding.
Long noncoding RNA AFAP1‑AS1 has been shown to promote tumor progression in several human cancer types, such as thyroid cancer, tongue squamous cell carcinoma and lung cancer. However, the role of ...AFAP1‑AS1 in osteosarcoma (OS) has not been investigated. In the present study, the expression of AFAP1‑AS1 was significantly upregulated in OS tissues and cell lines. Moreover, AFAP1‑AS1 expression was negatively correlated with OS patient prognosis. Besides, AFAP1‑AS1 knockdown significantly inhibited the proliferation and invasion of OS cells in vitro. Furthermore, in vivo xenograft experiments indicated that AFAP1‑AS1 depletion delayed tumor growth. Regarding the underlying mechanism, AFAP1‑AS1 served as a sponge to repress the level of microRNA (miR)‑4695‑5p, which targeted transcription factor (TCF)4, a pivot effector of Wnt/β‑catenin signaling pathway. It was demonstrated that overexpression of AFAP1‑AS1 inhibited the expression of miR‑4695‑5p, while miR‑4695‑5p overexpression decreased TCF4 expression and reduced activation of Wnt/β‑catenin pathway. Through rescue assays, it was demonstrated that restoration of TCF4 expression reversed the effects of AFAP1‑AS1 knockdown or miR‑4695‑5p overexpression on OS cells. Taken together, these findings demonstrated that the AFAP1‑AS1/miR‑4695‑5p/TCF4‑β‑catenin axis played an important role in OS progression.
There are many factors to consider in the field of tissue engineering. For articular cartilage repair, this includes seed cells, scaffolds and chondrotrophic hormones. This review primarily focuses ...on the seed cells and scaffolds. Extracellular matrix proteins provide a natural scaffold for cell attachment, proliferation and differentiation. The structure and composition of tissue-derived scaffolds and native tissue are almost identical. As such, tissue-derived scaffolds hold great promise for biomedical applications. However, autologous tissue-derived scaffolds also have many drawbacks for transplantation, as harvesting autografts is limited to available donor sites and requires secondary surgery, therefore imparting additional damage to the body. This review summarizes and analyzes various cell sources and tissue-derived scaffolds applied in orthopedic tissue engineering.
•Joint scRNA-seq and JAK2 genotyping were performed for patients with myeloproliferative neoplasms.•Interferon response genes are significantly more highly expressed in JAK2-V617F hematopoietic ...progenitors.•Monocytes with JAK2–V617F have a pro-inflammatory, intermediate monocyte phenotype.•JAK2–V617F monocytes express SLAMF7, which is associated with fibrosis in MPNs.
The JAK2–V617F mutation is the most common cause of myeloproliferative neoplasms. Although experiments have revealed that this gain-of-function mutation is associated with myeloid blood cell expansion and increased production of white cells, red cells, and platelets, the transcriptional consequences of the JAK2–V617F mutation in different cellular compartments of the bone marrow have not yet been fully elucidated. To study the direct effects of JAK2–V617F on bone marrow cells in patients with myeloproliferative neoplasms, we performed joint single-cell RNA sequencing and JAK2 genotyping on CD34+-enriched cells from eight patients with newly diagnosed essential thrombocythemia or polycythemia vera. We found that the JAK2–V617F mutation increases the expression of interferon-response genes (e.g., HLAs) and the leptin receptor in hematopoietic progenitor cells. Furthermore, we sequenced a population of CD34– bone marrow monocytes and found that the JAK2 mutation increased expression of intermediate monocyte genes and the fibrocyte-associated surface protein SLAMF7 in these cells.
Advanced materials such as aluminum alloys and composites offer great potential for weight reduction applications in automotive and aerospace vehicles construction. In order to investigate the ...feasibility of using such materials in the form of laminates, sheet bulging with single-layer aluminum and the aluminum/Composite laminate with the carbon cloth as the middle layer is investigated under uniform liquid pressure conditions. The aluminum sheet stress-strain, wall thickness distribution, carbon fiber radius stress-strain distribution and the effect of die entrance radius etc. are discussed and compared in details. FE results validate that the numerical method can predict the same fracture regions for bulging-blank as observed in experimental tests. Furthermore, the study validates that multi-layer sheet hydro-bulging process with composite fiber as a middle layer is not feasible to form laminates due to rupture of composite fibers near edge regions. Further study is needed to improve the methodology.
Poly(2‐methyl‐2‐oxazoline) (PMeOx), poly(2‐ethyl‐2‐oxazoline) (PEtOx), poly(2‐n‐butyl‐2‐oxazoline) (PBuOx), and poly(2‐phenyl‐2‐oxazoline) (PPhOx) are selected as poly(2‐oxazoline) (POX) models to ...study the effect of pendant groups on their blood compatibility and hydration states. A comprehension of this can provide a perspective for understanding the biocompatibility of PMeOx and PEtOx in water‐polymer interactions and may inspire the development of novel blood‐compatible POX derivatives. The aforementioned four POXs are grafted onto glass substrates via photo‐grafting, and their blood compatibility is estimated via platelet adhesion and the degree of denaturation of the adsorbed fibrinogen. The hydration states of the POXs are investigated using differential scanning calorimetry and attenuated total reflection infrared spectroscopy. Intermediate water is found to be present in hydrated PMeOx and PEtOx, but is observed to be scarce in hydrated PBuOx and PPhOx. This could be the reason for the biocompatibility of PMeOx and PEtOx. The carbonyl groups in PMeOx and PEtOx can be fully hydrated. However, in PBuOx and PPhOx, water mainly exists as bulk water. The hydration of the carbonyl groups is hindered by the bulky side chains, and IW cannot be generated.
The JAK2-V617F mutation is the most common cause of myeloproliferative neoplasms. While experiments have shown that this gain-of-function mutation is associated with myeloid blood cell expansion and ...increased production of white cells, red cells and platelets, the transcriptional consequences of the JAK2-V617F mutation in different cellular compartments of the bone marrow have not yet been fully elucidated. To study the direct effects of JAK2-V617F on bone marrow cells in myeloproliferative neoplasm patients, we performed joint single-cell RNA sequencing and JAK2 genotyping on CD34+ enriched cells from 8 patients with newly diagnosed essential thrombocythemia or polycythemia vera. We found that the JAK2-V617F mutation increases the expression of interferon-response genes (e.g., HLAs) and the leptin receptor in hematopoietic progenitor cells. Furthermore, we sequenced a population of CD34-bone marrow monocytes and found the JAK2 mutation increased expression of intermediate monocyte genes and the fibrocyte-associated surface protein SLAMF7 in these cells.
This study focused on the structure and the platform of the road space of historic districts. We analyzed the road networks of 16 historic districts in Japan from the perspectives of circularity, ...accessibility and indirection based on graph theory. By calculatin8 and comparing the indexes of each road network （NW1 and NW2） forms, we quantitatively describe the effects of the main prefectural roads （more than 4 m in width） and narrow streets （less than 4 m in width） on the spatial characteristics. And it turned out that we could divided the 16 objective historic districts into 4 types. Moreover, we qualitatively studied the characteristics of each type of historic districts based on their development background and the structure of road network.
In social networks, the identification of key nodes has become a hot research direction because of its important theoretical significance and extensive practical application. Most of the existing ...research modeling methods and selected indicators are designed on local information, and the overall topology of the network is insufficiently considered, which has certain limitations. Therefore, based on the overall topology of the network, this paper proposes a depth-weighted heuristic algorithm DWH-KPP-POS for the key player problem positive effects. Finally, the effectiveness and efficiency of the proposed model and algorithm are verified on various types of synthetic networks and real network datasets.
Disability and even death from acute thrombosis remain a grave menace to public health. At present, the traditional drugs represented by urokinase (UK) in clinical thrombolysis can cause side effects ...of bleeding when the dosage is excess. Therefore, a more effective and safer method of thrombolysis is urgently needed. In this paper, a multifunctional dual-drug sequential release thrombolysis platform (UK-UH@PDA@HMSNs) consisting of polydopamine (PDA)-modified hollow mesoporous silicon (HMSNs) loading with UK and unfractionated heparin (UH) was constructed with a double physical assistance (NIR-II and bubbles). With the aid of near infrared-II (NIR-II, 1064 nm, 1.0 W cm–2) laser, the photothermal effect of PDA could be motivated to facilitate the UH release, thereby accelerating the dissolution of thrombus. Afterward, the local hyperthermia effect could expedite the phase transition of l-menthol in HMSNs to generate bubbles to promote the release of UK, thereby realizing the sequential release of two thrombolytic drugs. Importantly, this method deftly conquered the inherent obstacle that UK and UH cannot be combined directly. In vivo and in vitro experiments proved that the thrombolytic efficiency of UK-UH@PDA@HMSNs stimulated by NIR-II was nearly 3 times than that of UK alone. Collectively, the proposed dual physical assistance and sequential dual-drug delivery system significantly improved the efficiency of thrombolysis under the premise of limiting drug doses; the risk of death from intracranial hemorrhage thus could be decreased radically.
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