Secondary Expansion Research Articles

Ribonuclease-1 treatment after traumatic brain injury preserves blood\u2013brain barrier integrity and delays secondary brain damage in mice

Traumatic brain injury (TBI) involves primary mechanical damage and delayed secondary damage caused by vascular dysfunction and neuroinflammation. Intracellular components released into the parenchyma and systemic circulation, termed danger-associated molecular patterns (DAMPs), are major drivers of vascular dysfunction and neuroinflammation. These DAMPs include cell-free RNAs (cfRNAs), which damage the blood–brain barrier (BBB), thereby promoting edema, procoagulatory processes, and infiltration of inflammatory cells. We tested the hypothesis that intraperitoneal injection of Ribonuclease-1 (RNase1, two doses of 20, 60, or 180 µg/kg) at 30 min and 12 h after controlled-cortical-impact (CCI) can reduce secondary lesion expansion compared to vehicle treatment 24 h and 120 h post-CCI. The lowest total dose (40 µg/kg) was most effective at reducing lesion volume (− 31% RNase 40 µg/kg vs. vehicle), brain water accumulation (− 5.5%), and loss of BBB integrity (− 21.6%) at 24 h post-CCI. RNase1 also reduced perilesional leukocyte recruitment (− 53.3%) and microglial activation (− 18.3%) at 120 h post-CCI, but there was no difference in lesion volume at this time and no functional benefit. Treatment with RNase1 in the early phase following TBI stabilizes the BBB and impedes leukocyte immigration, thereby suppressing neuroinflammation. RNase1-treatment may be a novel approach to delay brain injury to extend the window for treatment opportunities after TBI.

Challenges in the development of bispecific antibodies for non-Hodgkin lymphoma

In The Lancet Haematology, Rajat Bannerji and colleagues1 report the results of an ongoing phase 1 trial of the CD20×CD3 bispecific antibody, odronextamab, in B-cell non-Hodgkin lymphoma. CD3-bispecific antibodies work by forming a trimer that involves T cells and a surface antigen on the target cell, in this case, CD20 on malignant and non-malignant B-lymphocytes. Human leukocyte antigen (HLA)-independent activation of polyclonal T cells leads to lysis of the target cell. A secondary expansion of T-cell subsets and induction of inflammatory cytokines might follow,2 contributing to the clinical response and primary dose-limiting toxicity of cytokine release syndrome.

Detection method for surface scratches of composite automotive components with high reflection and complicated background color

Abstract Current testing status have the problems that the surface background color pattern of high reflective carbon fiber auto parts is complex, the shape of scratch defects is irregular, and the shallow and micro scratches are not easy to be detected. Aiming at the problems, a scratch detection method combining innovative morphological processing and optimized Canny edge detection algorithm is proposed. The image acquired by an innovative image acquisition platform. After gray processing and open operation denoising, the self-defined oval kernel secondary expansion is introduced in the morphological processing part. When threshold segmentation and minimum connected domain screening are done, the optimized Canny edge detection algorithm is used. Through the non-maximum suppression of gradient amplitude, a wide range of dual-threshold parameters are selected to detect the edge of the target image. The results show that the detection rate of the proposed method is 18.57% higher than that of the traditional way, and the detection rate is up to 95.71%. At the same time, the proposed method can reflect the scratch morphology more intuitively.

Autocrine and paracrine IL-2 signals collaborate to regulate distinct phases of CD8 Tcell memory.

Differential interleukin-2 (IL-2) signaling and production are associated with disparate effector and memory fates. Whether the IL-2 signals perceived by CD8 Tcells come from autocrine or paracrine sources, the timing of IL-2 signaling and their differential impact on CD8 Tcell responses remain unclear. Using distinct models of germline and conditional IL-2 ablation in post-thymic CD8 Tcells, this study shows that paracrine IL-2 is sufficient to drive optimal primary expansion, effector and memory differentiation, and metabolic function. In contrast, autocrine IL-2 is uniquely required during primary expansion to program robust secondary expansion potential in memory-fated cells. This study further shows that IL-2 production by antigen-specific CD8 Tcells is largely independent of CD4 licensing of dendritic cells (DCs) in inflammatory infections with robust DC activation. These findings bear implications for immunizations and adoptive Tcell immunotherapies, where effector and memory functions may be commandeered through IL-2 programming.

Construction of Artistic Design Patterns Based on Improved Distributed Data Parallel Computing of Heterogeneous Tasks

With the continuous upgrading of hardware in the terminal equipment, how to provide high-performance computing for low-tech threshold users has become a current research hotspot. In the era of green high-performance computing, the heterogeneous computing system can provide good versatility, performance, and efficiency and has broad development prospects. This article provides an in-depth analysis and research on the construction and application of improved models using the artistic design pattern of heterogeneous tasks and parallel computing. Based on the hardware resources in the existing desktop system, this article optimizes the original heterogeneous parallel technology from the aspects of task division and data transmission to reduce the complexity of data allocation and processing for users. Based on the analysis and study of the multicore CPU and GPU architectures in the desktop system, as well as the original CPU-GPU heterogeneous parallel technology, this article optimizes the solution of heterogeneous parallel computing, designs a heterogeneous parallel computing architecture, and deploys a heterogeneous parallel computing architecture. The nodes of the desktop system constitute the parallel computing system. In terms of task allocation, the computing system divides tasks according to the parallelism of tasks. According to the computing resources and bandwidth conditions of each heterogeneous node, starting from the parallel execution time, the task scheduling algorithm is optimized, and the load balancing scheduling scheme is designed to achieve the optimal allocation of resources. In terms of storage resources, the computing system adopts distributed storage as a whole. The CPU-GPU heterogeneous parallel in the desktop system adopts virtual unified storage. Global distributed storage and local shared storage are used to balance overall performance and programming complexity. This article introduces the design and implementation of JTangSync, a distributed heterogeneous data synchronization system. The system adopts a distributed architecture, and each node is organized by a data source module, a data transmission module, a processor module, etc. The data source module is responsible for extracting data, the data transmission module is mainly responsible for efficient data transmission, and the processor module is responsible for data processing. More importantly, each module is designed as a replaceable plug-in, which is convenient for secondary expansion. Each node relies on ZooKeeper to form a cluster, which realizes distributed functions such as centralized management of distributed resources, failover, and resumed transmission. Compared with the mainstream scheduling algorithms HEFT, CPOP, PEFT, and HSIP on heterogeneous systems participating in the experimental evaluation, the scheduling length ratio of DONF series algorithms is reduced by 36.3%–67.5% and the parallelism is increased by 17%–125% in terms of efficiency. Compared with the existing database synchronization system, the JTangSync system has built-in multiple heterogeneous database data sources and supports the synchronization of complex heterogeneous databases. The system supports users to develop and customize their own data sources and data processing programs, to promote secondary development. By adopting the custom compressed data exchange format and network optimization methods such as packet merging, caching, and adaptive compression algorithm, the system has high performance.

Secondary growth and closure behavior of planar hydraulic fractures during shut-in

The evolution of fractures during shut-in after hydraulic fracturing is an important topic in petroleum engineering. Considering the closure and secondary expansion of fractures during shut-in can further improve the accuracy of predicting hydraulic fracture parameters. Based on linear elastic fracture mechanics, elastic mechanics, and the implicit level set algorithm, a numerical model of planar hydraulic fracture propagation was established in this study. In the proposed model, the reservoir was considered as a homogeneous elastic medium, and the fluid loss was characterized using Carter's filtration model. The secondary propagation and fracture closure behavior during shut-in could be simulated by solving the strongly nonlinear system of fluid and stress coupling. Based on this model, the evolution behavior of hydraulic fractures during injection and shut-in was analyzed. According to the variation characteristics of the fracture length, the evolution process could be divided into three stages: fracture propagation during injection, secondary growth, and fracture stopping (but not closing). According to the variation characteristics of the fracture opening and net pressure, the evolution process could be divided into three stages: nonlinear increase, linear decrease, and gradual decrease. For low-permeability reservoirs, fracture closure and secondary propagation may take several times the injection time after shut-in, and the secondary propagation length may reach tens of meters. The results show that the larger the filtration coefficient, the faster the fracture closure will be, and the shorter the secondary propagation distance. The higher the viscosity of the fracturing fluid, the slower the fracture closure will be, while the secondary propagation distance is almost unaffected. The fracture toughness has little effect on the fracture closure and secondary propagation. The crack will close first in the region with large interlayer stress during shut-in. The findings of this study can help for better understanding of the evolution mechanism of fractures during shut-in and closure.

Social Climate and Teacher Professional Development in Tanzania

This article reports on the findings in relation to the implications of social climate for the professional development of teachers. The study was conducted in the context of the secondary education expansion plan in Tanzania which initiated the construction of new schools within communities. The main purpose of this study was to gain insights into how teachers’ interaction with diverse policy contexts shaped them to grow as teaching professionals. This study was qualitative in nature. Participants were 28 teachers from four community secondary schools. Data were collected by using individual and focus group interviews which were inductively analyzed. Findings identified specific social conditions within and beyond the school that impacted the development of teachers, and in turn, affected student learning achievement. The article suggests that improving the social climate enhances the sustainability of the teaching profession.

Molecular phylogeography reveals multiple Pleistocene divergence events in estuarine crabs from the tropical West Pacific.

Due to the lack of visible barriers to gene flow, it was a long-standing assumption that marine coastal species are widely distributed, until molecular studies revealed geographically structured intraspecific genetic differentiation in many taxa. Historical events of sea level changes during glacial periods are known to have triggered sequential disjunctions and genetic divergences among populations, especially of coastal organisms. The Parasesarma bidens species complex so far includes three named plus potentially cryptic species of estuarine brachyuran crabs, distributed along East to Southeast Asia. The aim of the present study is to address phylogeography and uncover real and hidden biological diversity within this complex, by revealing the underlying genetic structure of populations and species throughout their distribution ranges from Japan to West Papua, with a comparison of mitochondrial COX1 and 16S rRNA gene sequences. Our results reveal that the P. bidens species complex consists of at least five distinct clades, resulting from four main cladogenesis events during the mid to late Pleistocene. Among those clades, P. cricotum and P. sanguimanus are recovered as monophyletic taxa. Geographically restricted endemic clades are encountered in southeastern Indonesia, Japan and China respectively, whereas the Philippines and Taiwan share two clades. As individuals of the Japanese clade can also be found in Taiwan, we provide evidence of a third lineage and the occurrence of a potential cryptic species on this island. Ocean level retreats during Pleistocene ice ages and present oceanic currents appear to be the main triggers for the divergences of the five clades that are here addressed as the P. bidens complex. Secondary range expansions converted Taiwan into the point of maximal overlap, sharing populations with Japan and the Philippines, but not with mainland China.

Feeding ecology and epizootological value of the Great Cormorant (<i>Phalacrocorax carbo</i>) during the secondary expansion of the Baikal region

Aim . To research the Great Cormorant ( Phalacrocorax carbo L., 1758) ecology during the secondary expansion of the Baikal region. Material and Methods . The material for studying cormorant nutrition was 28 stomachs of harvested birds, visual observations of feeding cormorants using optical equipment, as well as regurgitated burps of nutrition obtained by a bloodless method when being fed to chicks. 21 examples of cormorants were the subjects of the parasitological research. Results . The number of the species has been growing since the beginning of the XXI century and, starting from 2020/21, is likely to stabilize, remaining at a high level. This indicates the gradual integration of the species into the Baikal Lake ecosystem. The main food item of Cormorants are the non‐commercial fish, Sleeper ( Percottus glehni Dyb.), Perch ( Perca fluviatilis L.) and Roach ( Rutilus rutilus L.). Parasitological studies have revealed 8 species of helminths from three classes with varying degrees of invasion. Only one of them, Contracaecum osculatum baicalensis (Mosgovoy et Ryjikov, 1950), is endemic and potentially dangerous to human health (its infection rate can reach 80%). Conclusion . The Great Cormorant is an obligate, but not a specialized ichthyophage, focused on the prevailing fish species. Great Cormorants as hosts of ticks, helminths and other ecto‐ and endoparasites are potentially sources of threat to the occurrence and spread, primarily, of ornithoses and helminthiasis in the Baikal region and possibly of other diseases carried from their wintering places.

Three-Dimension Co-culture of Hematopoietic Stem Cells and Differentiated Osteoblasts on Gallic Acid Grafted-Chitosan Scaffold as a Model of Hematopoietic Stem Cells Niche.

The existing approaches of hematopoietic stem cells (HSCs) expansion in vitro were difficult to meet the needs of clinical application. While in vivo, HSCs efficiently self-renew in niche where they interact with three dimension extracellular matrix and stromal cells. Osteoblasts (OBs) are one of most significant stromal cells of HSCs niche. Here, we proposed a three-dimensional environment based on gallic acid grafted-chitosan (2c) scaffold and OBs differentiated from human umbilical cord mesenchymal stem cells (HUMSCs) to recapitulate the main components of HSCs niche. The results of alkaline phosphatase staining and alizarin red staining demonstrated that HUMSCs were successfully induced into OBs. The results showed that the expansions of CD34+cells, CD34+CD38- cells and CD34+CD38-CD45RA-CD49f+CD90+ cells (primitive hematopoietic stem cells, pHSCs) harvested from the biomimetic HSCs niche based on 2c scaffold and OBs (IV) group were larger than those harvested from other three culture groups. Importantly, it was found that the CD34+ cells harvested from IV group had better secondary expansion capability and colony forming potential, indicating better self-renewal ability. In addition, the biomimetic HSCs niche based on 2c scaffold and OBs protected HSCs apoptosis and promoted HSCs division. Taken together, the biomimetic HSCs niche based on 2c scaffold and OBs was an effective strategy for ex vivo expansion of HSCs in clinical scale.

Preparation of concrete specimen for internal sulfate attack analysis using electron backscatter diffraction

AbstractConcrete cores were obtained from houses in eastern Connecticut, USA, that had varying degrees of crumbling foundations and wall cracking. Electron backscatter diffraction (EBSD) was used simultaneously with energy dispersive X‐ray spectroscopy to investigate the degradation of these samples. This combination allowed the precise correlation of elemental composition with mineral crystallography phase mapping. EBSD examination showed the presence of pyrrhotite, pyrite, and marcasite phases in some of the samples, whereas internal sulfate attack (ISA) is triggered by the release of sulfates through the oxidation of such iron sulfides. Secondary expansion products from ISA are associated with foundation cracking, wall bulging, and drastically decreased structural stability. The main contribution of this study is therefore an automated procedure for preparation of concrete samples and analysis of aggregates using EBSD.

Research on the influence of different obstacle structures on the energy distribution characteristics of pulse detonation gas

In order to improve the gas energy conversion efficiency at the outlet of the pulse detonation combustor, numerical calculation methods were used to study the influence of three different cross-section obstacle structures of square, circle and trapezoid on the distribution characteristics of gas pressure potential energy, kinetic energy and internal energy in a single cycle at the outlet of pulse detonation combustor. The results show that: the expansion of pulse detonation gas mainly includes three-stages: primary expansion, secondary expansion, and over-expansion. Gas pressure potential energy, kinetic energy, and internal energy increase during the primary and secondary expansion stages, and decrease during the over-expansion stage. Pulse detonation combustor with trapezoidal cross-section obstacle structure has the smallest proportion of gas energy at the outlet of the combustor during the over-expansion stage and the highest proportion during the secondary expansion stage. Compared with square and circle cross-section obstacle structures, the gas energy distribution at the outlet of the pulse detonation combustor with trapezoidal cross-section obstacle structure is the easiest for turbomachinery to convert the gas energy.

Early and midterm outcomes following open surgical conversion after failed endovascular aneurysm repair from the "Italian North-easT RegIstry of surgical Conversion AfTer Evar" (INTRICATE).

To report the early and mid-term outcomes following open surgical conversion (OSC) after failed endovascular aortic repair (EVAR) using data from a multicentric registry. A retrospective study was carried out on consecutive patients undergoing OSC after failed EVAR at eight tertiary vascular units from the same geographic area in the North-East of Italy, from April 2005 to November 2019. Study endpoints included early and follow-up outcomes. A total of 144 consecutive patients were included in the study. Endoleaks were the most common indication for OSC (50.7%), with endograft infection (24.6%) and occlusion (21.9%) being the second most prevalent causes. The overall rate of 30-day all-cause mortality was 13.9% (n= 20); 32 patients (22.2%) experienced at least one major complication. Mean length of stay was 13± 12.7days. On multivariate logistic regression, age (odds ratio [OR], 1.09; 95% confidence interval [CI], 1.01-1-19; P= .02), renal clamping time (OR, 1.07; 95% CI, 1.02-1.13; P= .01), and suprarenal/celiac clamping (OR, 6.66; 95% CI, 1.81-27.1; P= .005) were identified as independent predictors of perioperative major complications. Age was the only factor associated with perioperative mortality at 30days. Renal clamping time >25minutes had sensitivity of 65% and specificity of 70% in predicting the occurring of major adverse events (area under the curve, 0.72; 95% CI, 0.61-0.82). At 5years, estimated survival was significantly lower for patients treated due to aortic rupture/dissection (28%; 95% CI, 13%-61%), compared with patients in whom the indication for treatment was endoleak (54%; 95% CI, 40%-73%), infection (53%; 95% CI, 30%-94%), or thrombosis (82%; 95% CI, 62%-100%; P= .0019). Five-year survival rates were significantly lower in patients who received emergent treatment (28%; 95% CI, 14%-55%) as compared with those who were treated in an urgent (67%; 95% CI, 48%-93%) or elective setting (57%; 95% CI, 43%-76%; P= .00026). Subjects who received suprarenal/celiac (54%; 95% CI, 36%-82%) or suprarenal (46%; 95% CI, 34%-62%) aortic cross-clamping had lower survival rates at 5years than those whose aortic-cross clamp site was infrarenal (76%; 95% CI, 59%-97%; P= .041). Using multivariate Cox proportional hazard, older age and emergency setting were independently associated with higher risk for overall 5-year mortality. OSC after failed EVAR was associated with relatively high rates of early morbidity and mortality, particularly for emergency setting surgery. Endoleaks with secondary sac expansion were the main indication for OSC, and suprarenal aortic cross-clamping was frequently required. Endograft infection and emergent treatment remained associated with poorer short- and long-term survival.

Development and Application of Water Sealing Technology for Gas Drainage Boreholes.

The poor sealing effect of gas extraction boreholes causes low efficiency of gas extraction. As a consequence, the requirements of coal mine safety production are often not attained. The sealing effect of boreholes depends not only on the sealing material itself but also on the combination degree between the material and the hole wall and the structural change characteristics of the material during operation. Our theoretical analysis shows that the amount of liquid leakage increases with the gap width Δh in a cubic law, decreases with the sealing hole viscosity in a hyperbolic form, increases linearly with the diameter of the borehole, and increases with the eccentricity in a quadratic function. We have developed a PD sealing material that has good compactness and sealing effects, excellent water retention performance, and an expansion rate of 1.29. The material can generate secondary expansion through microscopic development, which is beneficial to improve the quality of the sealing hole. HV-CMC has good stability in plugging mucus. In addition, the manual pump has been redeveloped to be portable and also to overcome the blockage of the suction valve of the original device. In addition, the auxiliary device for drilling and sealing has been invented. The field application demonstrates that the gas concentration and flow pressure difference of the new sealing borehole can be maintained at a high level in a short period of time and then decrease slowly with time. The resulting improved sealing effect demonstrates that our new approach has important theoretical and practical significance for mine gas drainage.

The first fossilized comb-clawed beetle of the genus Asiomira Dubrovina, 1973 (Coleoptera: Tenebrionidae: Alleculinae) from Baltic Amber and notes on the distribution of extant species of the genus.

A new species of comb-clawed beetles of the genus Asiomira Dubrovina, 1973 (A. dubrovinae sp. n.) is described from the Eocene Baltic amber. This newly descovered fossil species displays typical generic characters and is the most similar to the extant Asiomira ophtalmica (Seidlitz, 1896). Both species share a similar shape of the pronotum and the flattened posterior angles of the pronotal disc. Asiomira dubrovinae sp. n. can be distinguished from A. ophtalmica by the smaller body size (4.8 mm in contrast to 68.12 mm), more serrate antennomeres, and finer and sparser pronotal punctation. Extant species of the genus are distributed in the arid landscapes of Central Asia with the highest diversity occurring in Tajikistan. Therefore the discovery of a new fossil species from Eocene Baltic amber suggests that Asiomira could have a wider range, and the modern distribution of this group is the result of a later secondary expansion of the ancestral representatives that survived in mid-mountain areas with arboreal and shrub vegetation. Relevant corrections to the distribution of extant species, Asiomira ophtalmica (Seidlitz, 1896) and Asiomira firjusana (Dubrovina, 1973), are given.

Removal of CD34− cells to increase self-renewal symmetric division and expansion ex vivo of cord blood CD34+ cells through reducing the TGF-β1

Haematopoietic stem cells (HSCs) exist in CD34+ cells and lose CD34 marker expression when they differentiate into CD34− cells during ex vivo expansion. In this work, periodical removal of CD34− cells with full medium replacement and full medium replacement were performed to investigate the influence of CD34− cells on the expansion of CD34+ cells. After 10 days of culture, the percentages of CD34+ cells with symmetric self-renewing division cultured according to these two strategies were significantly higher than those in the control group. As a result, by using these two strategies, the concentrations of total TGF-β1 and activated TGF-β1 were investigated and were significantly reduced compared with those in the control group. The expansion of CD34+ cells was significantly greater than that of control cells. Importantly, the expansion of CD34+CD38−CD45RA−CD49f+CD90+ cells was also significantly increased. Moreover, both of the two strategies better maintained the colony-forming ability and secondary expansion ability of cells. The qRT-PCR results further indicated that key genes involved in the self-renewal and function of HSCs were upregulated (pu.1, hoxa9, hoxb4, hes1 and bmi1). Therefore, we speculated that CD34− cells inhibited the expansion of CD34+ cells by TGF-β1.

MEK1 activation enhances the ex vivo proliferation of haematopoietic stem/progenitor cell.

Haematopoietic stem/progenitor cell (HSPC) integrates intracellular signal network from growth factors (GFs) and utilizes its proliferation feature to generate high yields of transplantable cells upon ex vivo culture. However, the molecular basis for HSPC activation and proliferation is not completely understood. The goal of this study was to investigate proliferation regulator in the downstream of GFs and develop HSPC expansion strategy. Microarray and Ingenuity Pathway Analysis were performed to evaluate differentially expressed genes in cytokine-induced CD34+ cells after ex vivo culture. We identified that MEK1 was a potential HSPC proliferation regulator, which represented indispensable roles and MEK1 silence attenuated the proliferation of HSPC. Notably, 500 nM MEK1 agonist, PAF C-16, increased the numbers of phenotypic HSPC and induced cell cycling of HSPC. The PAF C-16 expanded HSPC demonstrated comparative clonal formation ability and secondary expansion capacity compared to the vehicle control. Our results provide insights into regulating the balance between proliferation and commitment of HSPC by targeting the HSPC proliferation-controlling network. This study demonstrates that MEK1 critically regulates HSPC proliferation and cell production in the ex vivo condition for transplantation.

Population genetic diversity and genetic evaluation models reveal the maternal genetic structure and conservation priority characteristics of indigenous cattle in China

The population genetic structure of domestic animals and the protection of genetic resources are major issues of concern in the field of global biology. In this study, the mtDNA D -loop sequences of 1163 Chinese indigenous cattle ( Bos taurus and Bos indicus ) were used to analyze their maternal origin and population genetic structure and to prioritize conservation evaluations based on a population genetic evaluation model. The results revealed three maternal origins or domestication events among Chinese indigenous cattle and the occurrence of secondary expansions but also the phenomenon of gene penetration. The population genetic evaluation model results showed that the genetic diversity of Huangpi cattle (HHP), Mountainous cattle (CMO), Bashan cattle (SBS) and Guanling cattle (GGL)populations was highest and that the Zaosheng cattle (GZN), Qinchuan cattle (SQB) and Pingliang cattle (GPL) populations contributed most to the richness of Chinese indigenous cattle genetic resources, indicating that these populations should be protected first. Our research provides a scientific basis and effective evaluation methods for the protection of genetic resources of indigenous livestock varieties.

Abstract 12446: Lipocalin10 Deficiency Exacerbates Myocardial Ischemia/Reperfusion Injury via Impairing Macrophage Efferocytosis

Introduction: Efficient clearance of dead cells by macrophages (termed as efferocytosis) is critical for timely repairing the injured heart after ischemia/reperfusion (I/R), as defective removal of dying cells could cause secondary necrosis and infarct expansion. Recent studies have shown that lipocalin 10 (Lcn10) is significantly downregulated in cardiac tissue from patients with heart failure. However, the role of Lcn10 is virtually unknown during cardiac I/R, and its function in macrophage efferocytosis has never been explored. Hypothesis: Our initial data showed that Lcn10 expression was upregulated in bone marrow-derived macrophages (BMDMs) during efferocytosis. Thus, we hypothesize that knockout (KO) of Lcn10 would diminish macrophage efferocytosis, leading to exacerbated cardiac I/R injury. Methods/Results: Since Lcn10 is a secreted protein, we generated a global Lcn10-KO mouse model. After co-culturing BMDMs with GFP-labeled dead myocytes for 2h, we observed a 25% reduction on efferocytosis by KO-BMDMs, compared to wild-type (WT) controls. Using Lcn10-KO mCherry mouse model (cardiac-specific overexpression of mCherry in Lcn10-KO mice), we detected that KO cardiac macrophages ingested fewer dead myocytes at 3 days post-I/R, compared to WT-mCherry controls. Accordingly, cardiac contractile function, measured by echocardiography at the same time, was significantly declined in KO-mice, together with increased accumulation of apoptotic cells and higher serum levels of troponin I, a marker of cardiac damage, compared with WTs (n=7-10, p <0.05). In addition, pre-treatment of KO-BMDMs with recombinant Lcn10 protein could rescue the impaired efferocytosis. Mechanistically, RNA-seq analysis showed that many downregulated genes (i.e., ItgaV, Itga6, Cx3cr1, and Msr) in KO-macrophages are associated with efferocytosis. Interestingly, we identified that Lcn10 contains a potential phosphatidylserine (PS)-binding motif (RxKRK), located at a helix-turn-helix structure, which is the primary “find-me” signal for efferocytosis. Conclusions: Our data indicate that Lcn10 is pivotal for macrophage efferocytosis to remove cardiac dead cells during I/R. Thus, Lcn10 could be used as a new mediator for the treatment of cardiac I/R injury.

Delivery of IL-2 to the T Cell Surface Through Phosphatidylserine Permits Robust Expansion of CD8 T Cells.

The phospholipid phosphatidylserine (PS) is naturally maintained on the cytoplasmic side of the plasma membrane. Independent of apoptosis, PS is redistributed to the surface of CD8 T cells in response to TCR-mediated activation. Annexin V (AnnV) is a protein known to bind PS with high affinity and has been effectively utilized to anchor antigen to the surface of CD8 T cells. To expand these studies, we aimed to exploit TCR activation driven PS exposure as a target to deliver cytokine, namely interleukin-2 (IL-2), to the surface of CD8 T cells. This was accomplished using a novel chimeric fusion protein of annexin V and interleukin 2 (AnnV-IL2). In vitro analysis revealed that AnnV-IL2 is able to specifically bind PS on the T cell surface following TCR stimulation. Consequently, AnnV-IL2 proved to be significantly more effective at enhancing T cell activation compared to recombinant IL-2. In vivo, AnnV-IL2 promotes robust expansion of antigen-specific cells capable of interferon gamma (IFNγ) production when administered following peptide vaccination. Importantly, upon antigen rechallenge, AnnV-IL2 treatment mice demonstrated a stronger secondary expansion, indicating durability of AnnV-IL2 mediated responses. Our data supports the use of AnnV-IL2 to modulate antigen-specific T cell immunity and demonstrates that the PS-AnnV axis is a feasible mechanism to target diverse cargo to CD8 T cells.