Efficient Clearance Research Articles

Розвиток митної інфраструктури на україно-польському кордоні в умовах інтернаціоналізації бізнесу

The relations between Ukraine and Poland represent a long history of partnership and have a great economic importance for both countries. At the present stage, Poland is one of the largest international trade partners of our country. In the history of Ukraine's foreign trade during 2019-2020, Poland occupied second place in the structure of domestic exports. Thus, in 2020 the share of exports of Ukrainian goods to Poland was 6.65%. First of all, it means a change in the vector of foreign trade development for the national economy and the reorientation of Ukraine's export market to the European Union. In 2020, Poland also occupied one of the leading positions in the structure of Ukrainian imports of goods (4th place with a share of 7.62%). This situation leads to a significant increase in the load at checkpoints and causes the need to ensure prompt and efficient customs clearance of goods moving across the Ukrainian-Polish border. On the basis of the performed researches, significant differences in the levels of development of the customs services of Poland and Ukraine in terms of the quality of customs services have been established, as Ukraine lags far behind Poland in all the studied indicators in this area. Such situation requires the improvement of the work of Ukrainian customs authorities in the context of business internationalization, including the development of customs infrastructure in the area of the Ukrainian-Polish border. The key problems of customs service of enterprises at domestic checkpoints include long and costly customs procedures, lack of proper technical, road, information infrastructure at checkpoints, outdated technical instruments of customs control, etc. It is proved that in the conditions of business internationalization one of the key tasks should be the construction of new checkpoints and the development of the customs infrastructure of the existing checkpoints. The key strategically important checkpoints in the area of the Ukrainian-Polish border, which need to be modernized in order to increase their capacity, include road checkpoints "Korchova-Krakivets", "Dorokhusk-Yagodyn", "Medyka-Shehyni", as well as a railway checkpoint "Medyka-Mostyska". In addition, the importance of spreading the practice of construction of joint checkpoints, which allows to significantly speed up the process of customs services for businesses, was emphasized.

Overexpression of Cystine/Glutamate Antiporter xCT Correlates with Nutrient Flexibility and ZEB1 Expression in Highly Clonogenic Glioblastoma Stem-like Cells (GSCs)

Simple SummaryGlioblastoma (GBM) is the most aggressive form of glioma (WHO grade IV), and mounting evidence suggests that glioblastoma stem-like cells (GSCs) play an important role in tumor growth and response to therapy. In the current study, we sought to understand the metabolic dependencies of GSCs using high-resolution proton magnetic resonance spectroscopy (1H-NMR). In a defined experimental setting, we stratified in vitro GSC models into two subtypes (Gln/GluHigh, Gln/GluLow) and used diverse molecular approaches to perform comprehensive analyses in GSC neurosphere cultures and primary GBM samples.Cancer stem-like cells mediate tumor initiation, progression, and therapy resistance; however, their identification and selective eradication remain challenging. Herein, we analyze the metabolic dependencies of glioblastoma stem-like cells (GSCs) with high-resolution proton nuclear magnetic resonance (1H-NMR) spectroscopy. We stratify our in vitro GSC models into two subtypes primarily based on their relative amount of glutamine in relationship to glutamate (Gln/Glu). Gln/GluHigh GSCs were found to be resistant to glutamine deprivation, whereas Gln/GluLow GSCs respond with significantly decreased in vitro clonogenicity and impaired cell growth. The starvation resistance appeared to be mediated by an increased expression of the glutamate/cystine antiporter SLC7A11/xCT and efficient cellular clearance of reactive oxygen species (ROS). Moreover, we were able to directly correlate xCT-dependent starvation resistance and high Gln/Glu ratios with in vitro clonogenicity, since targeted differentiation of GSCs with bone morphogenic protein 4 (BMP4) impaired xCT expression, decreased the Gln/Glu ratio, and restored the sensitivity to glutamine starvation. Moreover, significantly reduced levels of the oncometabolites lactate (Lac), phosphocholine (PC), total choline (tCho), myo-inositol (Myo-I), and glycine (Gly) were observed in differentiated GSCs. Furthermore, we found a strong association between high Gln/Glu ratios and increased expression of Zinc finger E-box-binding homeobox 1 (ZEB1) and xCT in primary GBM tumor tissues. Our analyses suggest that the inhibition of xCT represents a potential therapeutic target in glioblastoma; thus, we could further extend its importance in GSC biology and stress responses. We also propose that monitoring of the intracellular Gln/Glu ratio can be used to predict nutrient stress resistance.

A two-adjuvant multiantigen candidate vaccine induces superior protective immune responses against SARS-CoV-2 challenge.

An ideal vaccine against SARS-CoV-2 is expected to elicit broad immunity to prevent viral infection and disease, with efficient viral clearance in the upper respiratory tract (URT). Here, the N protein and prefusion-full S protein (SFLmut) are combined with flagellin (KF) and cyclic GMP-AMP (cGAMP) to generate a candidate vaccine, and this vaccine elicits stronger systemic and mucosal humoral immunity than vaccines containing other forms of the S protein. Furthermore, the candidate vaccine administered via intranasal route can enhance local immune responses in the respiratory tract. Importantly, human ACE2 transgenic mice given the candidate vaccine are protected against lethal SARS-CoV-2 challenge, with superior protection in the URT compared with that in mice immunized with an inactivated vaccine. In summary, the developed vaccine can elicit a multifaceted immune response and induce robust viral clearance in the URT, which makes it a potential vaccine for preventing disease and infection of SARS-CoV-2.

Heterogeneity in antiviral B cell responses: Lessons from the movies.

Humoral and cellular responses to viral infections coexist in a dynamic equilibrium that often results in efficient viral clearance. However, in some infections one of the two responses prevails, for instance when an overactivation of cytotoxic T cells is accompanied by weak and insufficient antibody responses. Although the cellular response is usually sufficient to control a primary viral infection, in some cases clearance is not complete and persistent infections ensue. In order to design effective therapeutic or vaccination strategies aiming at inducing early and potent neutralizing antibody responses, a deep knowledge of the cellular and molecular determinants of antiviral immune responses is needed. Here, we review our understanding on the spatiotemporal dynamics of antiviral humoral immune responses, with a particular focus on recent studies using intravital imaging approaches as an insightful complement to more traditional techniques.

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.

Targeting the Membrane-Proximal C2-Set Domain of CD33 for Improved CD33-Directed CAR T Cell Therapy

Background: There is increasing interest in targeting CD33 in malignant and non-malignant disorders, but available drugs are ineffective in many patients. As one limitation, therapeutic CD33 antibodies typically recognize the membrane-distal V-set domain. Likewise, currently tested CD33-directed chimeric antigen receptor (CAR) T cells likewise target the V-set domain and have thus far shown limited clinical activity. We have recently demonstrated that binding closer to the cell membrane enhances the effector functions of CD33 antibodies. We therefore raised antibodies against the membrane-proximal C2-set domain of CD33 and identified antibodies that bound CD33 regardless of the presence/absence of the V-set domain (“CD33 PAN antibodies”). Here, we tested their properties as targeting moiety in CD33 PAN CAR T cell constructs, using a clinically validated lentiviral backbone.Methods: To generate CAR T cells, negatively selected CD8 + T cells were transduced with an epHIV7 lentivirus encoding the scFv from a CD33 PAN antibody (clone 1H7 or 9G2) linked to either a short (IgG 4 hinge only), intermediate (hinge plus IgG 4 CH3 domain), or long (hinge plus IgG 4 CH3 domain plus IgG 4 CH2 domain) spacer, the CD28-transmembrane domain, CD3zeta and 4-1BB intracellular signaling domains, and non-functional truncated CD19 (tCD19) as transduction marker. Similar constructs using scFvs from 2 different V-set domain-targeting CD33 antibodies, including hP67.6 (My96; used in gemtuzumab ozogamicin), were generated for comparison. CAR-T cells were sorted, expanded in IL-7 and IL-15, and used in vitro or in vivo against human AML cell lines endogenously expressing CD33 and cell lines engineered to lack CD33 (via CRISPR/Cas9) with/or without forced expression of different CD33 variants.Results: CD33 V-set-directed CAR T cells exerted significantly more cytolytic activity against AML cells expressing an artificial CD33 variant lacking the C2-set domain (CD33 ΔE3-4) than cells expressing full-length CD33 at similar or higher levels, consistent with the notion that CD33 CAR T cell efficacy is enhanced when targeting an epitope that is located closer to the cell membrane. CD33 PAN CAR T cells were highly potent against human AML cells in a strictly CD33-dependent fashion, with constructs containing the short and intermediate-length spacer demonstrating robust cytokine secretion, cell proliferation, and in vitro cytolytic activity, as determined by 51Cr release cytotoxicity assays. When compared to optimized CD33 V-set CAR T cells, optimized CD33 PAN CAR T cells were significantly more potent in cytotoxicity, proliferation, and cytokine production without appreciably increased acquisition of exhaustion markers. In vivo, CD33 PAN CAR T cells extended survival in immunodeficient NOD.SCID. IL2rg -/- (NSG) mice bearing significant leukemic burdens from various cell line-derived xenografts (HL-60, KG1α and MOLM14) with efficient tumor clearance demonstrated in a dose-dependent fashion.Conclusion: Targeting the membrane proximal domain of CD33 enhances the anti-leukemic potency of CAR T cells. Our data provide the rationale for the further development of CD33 PAN CAR T cells toward clinical testing. DisclosuresFiorenza: Link Immunotherapeutics: Consultancy; Bristol Myers Squibb: Research Funding. Godwin: Pfizer: Research Funding; Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Turtle: Allogene: Consultancy; Amgen: Consultancy; Arsenal Bio: Consultancy; Asher bio: Consultancy; Astrazeneca: Consultancy, Research Funding; Caribou Biosciences: Consultancy, Current holder of individual stocks in a privately-held company; Century Therapeutics: Consultancy, Other; Eureka therapeutics: Current holder of individual stocks in a privately-held company, Other; Juno therapeutics/BMS: Patents & Royalties, Research Funding; Myeloid Therapeutics: Current holder of individual stocks in a privately-held company, Other; Nektar therapeutics: Consultancy, Research Funding; PACT Pharma: Consultancy; Precision Biosciences: Current holder of individual stocks in a privately-held company, Other; T-CURX: Other; TCR2 Therapeutics: Research Funding. Walter: Kite: Consultancy; Janssen: Consultancy; Genentech: Consultancy; BMS: Consultancy; Astellas: Consultancy; Agios: Consultancy; Amphivena: Consultancy, Other: ownership interests; Selvita: Research Funding; Pfizer: Consultancy, Research Funding; Jazz: Research Funding; Macrogenics: Consultancy, Research Funding; Immunogen: Research Funding; Celgene: Consultancy, Research Funding; Aptevo: Consultancy, Research Funding; Amgen: Research Funding.

Diphtheria Toxin Based Bivalent Anti-cMPL Immunotoxin Effectively Depletes Human Hematopoietic Stem and Progenitor Cells

Patient conditioning is a critical initial step in hematopoietic stem and progenitor cell (HSPC) transplantation procedures to enable marrow engraftment of infused cells. Preparative regimens have traditionally been achieved by delivering cytotoxic doses of chemotherapeutic agents, with or without radiation. However, these regimens impair host immune function and are associated with significant morbidity. The use of monoclonal antibodies, either alone or conjugated to an internalizing toxin, to target specific antigens on hematopoietic cells has been proposed as a tractable alternative, especially in contexts, such as ex vivo autologous gene therapy, where preservation of immunity is desired. Efficient clearance of marrow has been demonstrated in preclinical models using CD45- or CD117-targeting antibodies conjugated to the plant toxin Saporin. However, this approach still awaits demonstration of long-term safety and efficacy in humans. In this study, we investigated whether toxin-conjugated antibodies targeting the cMPL receptor on HSPCs can provide the basis for a conditioning regimen prior to transplant. Thrombopoietin (TPO) and its receptor cMPL act as primary regulators of HSPC self-renewal and survival. The TPO:cMPL axis also regulates megakaryopoiesis and platelet production but, unlike CD45 and CD117 proteins, cMPL is otherwise not expressed in other blood cell types or in non-hematopoietic tissues. Hence, this approach may uniquely allow effective and specific depletion of host HSCs while sparing most hematopoietic progenitors and mature blood cells.To investigate cMPL as an antigen for targeted depletion of human HSPCs, we produced a recombinant bivalent anti-cMPL single-chain variable fragment (sc(FV) 2) (Orita et al. Blood 2004) fused with diphtheria toxin truncated at residue 390 (DT390) to prevent toxin internalization in off-target cells. We first confirmed the cMPL receptor-dependent cytotoxic effects of the anti-cMPL-DT390 conjugate in a HEK293A cell line engineered to express the human cMPL receptor. We observed marked cellular killing in vitro (IC50 = 21 pM) compared to the cMPL-negative control HEK293A cell line (Fig. A). Next, we assessed anti-cMPL-DT390 for its ability to inhibit growth of human CD34+ cells in vitro. G-CSF mobilized peripheral blood (PB) CD34+ cells were obtained from five healthy individuals. Surface expression of cMPL was compared by flow cytometry in subsets increasingly enriched in cells with long-term repopulating activity, including bulk CD34+, CD34+CD38- and CD34+CD38-CD90+CD45RA-CD49f+ cells. Levels of cMPL expression increased congruently with levels of HSC purity (Fig. B). Consistent with a cMPL dependent cytotoxic effect, increased cellular death was measured in populations expressing higher densities of cMPL receptors (IC50 = 104 nM), suggesting preferential targeting of the most primitive hematopoietic compartment (Fig. C). We then assessed whether anti-cMPL-DT390 could safely target and deplete human HSPCs in vivo in humanized NBSGW immunodeficient mice. At 12 weeks post-transplantation, engrafted animals (mean 19.8% CD45+ cells in PB) received a single maximum tolerated dose of 1.2 mg/kg anti-cMPL-DT390 (n=7) or vehicle control solution (n=7) by tail vein injection. HSPC depletion was assayed by measuring human myeloid (CD45+CD13+) chimerism in the mouse PB after antibody administration. We observed a gradual decline in HSPC activity, as represented by the decreased production of human myeloid cells following administration of anti-cMPL-DT390, peaking at 6 weeks with a 2.6-fold reduction in frequency of human CD45+CD13+ cells compared to untreated animals (p = 0.003) (Fig. D).Overall, our study provides proof-of-concept that bivalent anti-cMPL immunotoxin can effectively target and deplete human HSPCs, and may thus provide a novel nontoxic preparative approach to improve HSPC engraftment in transplantation for genetic and other nonmalignant disorders. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Differential Clearance of Aβ Species from the Brain by Brain Lymphatic Endothelial Cells in Zebrafish.

The failure of amyloid beta (Aβ) clearance is a major cause of Alzheimer’s disease, and the brain lymphatic systems play a crucial role in clearing toxic proteins. Recently, brain lymphatic endothelial cells (BLECs), a non-lumenized lymphatic cell in the vertebrate brain, was identified, but Aβ clearance via this novel cell is not fully understood. We established an in vivo zebrafish model using fluorescently labeled Aβ42 to investigate the role of BLECs in Aβ clearance. We discovered the efficient clearance of monomeric Aβ42 (mAβ42) compared to oligomeric Aβ42 (oAβ42), which was illustrated by the selective uptake of mAβ42 by BLECs and peripheral transport. The genetic depletion, pharmacological inhibition via the blocking of the mannose receptor, or the laser ablation of BLECs resulted in the defective clearance of mAβ42. The treatment with an Aβ disaggregating agent facilitated the internalization of oAβ42 into BLECs and improved the peripheral transport. Our findings reveal a new role of BLECs in the differential clearance of mAβ42 from the brain and provide a novel therapeutic strategy based on promoting Aβ clearance.

Use of Mixture Dosing and Nonlinear Mixed Effect Modeling of Eight Environmental Contaminants in Rabbits to Improve Extrapolation Value of Toxicokinetic Data.

Background:Although in vivo studies of internal exposure to hazardous substances have been carried out for many years, there is room for progress to improve their informative value while adhering to the four R’s: replacement, reduction, refinement, and responsibility rule.Objectives:The objective of the study was to illustrate how toxicokinetic (TK) study design and data analysis can be implemented under the 4R rule to plan a chronic dosage regimen for investigating TK/toxicodynamic (TD) relationships.Methods:The intravenous (IV) and oral serum concentrations of eight hazardous environmental contaminants including 1,1-Dichloro-2,2-bis(p-chlorophenyl)ethylene (pp′DDE), (), hexachlorobenzene (HCB), 2,2′4,4′-tetrabromodiphenyl ether (BDE-47), perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), di(2ethylhexyl)phthalate (DEHP), and bisphenol S (BPS) were obtained after mixture dosing in rabbits using a sparse sampling design. Data were comprehensively analyzed using nonlinear mixed effect (NLME) modeling.Results:The short persistence of BPS and of the DEHP metabolite (mono-2-ethylhexyl phthalate), reflected by their mean residence times (MRT) of a few hours, was due to their efficient clearance (CL, 3.2 and ). The longer MRT of the other compounds (1–48 d) resulted either from their extremely low clearance (lower than for PFOA and PFOS) or from their very large volume of distribution () ranging from 33 to . Estimates of CL, , and bioavailability were used to compute the oral loading and daily maintenance doses required to attain a nominal steady-state serum concentration of . Simulations with the NLME model were applied to predict the serum concentration profile and to contrast the differential rates of accumulation in the central vs. peripheral compartments.Conclusion:NLME modeling of the IV and oral TK of hazardous environmental contaminants, in rabbits while fulfilling the 4R rule, was able to provide the physiological basis for interspecies extrapolation of exposure rates in a TK/TD approach to risk assessment. https://doi.org/10.1289/EHP8957

Therapeutic Effect of an Antibody-Derived Peptide in a Galleria mellonella Model of Systemic Candidiasis.

The synthetic peptide T11F (TCRVDHRGLTF), with sequence identical to a fragment of the constant region of human IgM, and most of its alanine-substituted derivatives proved to possess a significant candidacidal activity in vitro. In this study, the therapeutic efficacy of T11F, D5A, the derivative most active in vitro, and F11A, characterized by a different conformation, was investigated in Galleria mellonella larvae infected with Candida albicans. A single injection of F11A and D5A derivatives, in contrast with T11F, led to a significant increase in survival of larvae injected with a lethal inoculum of C. albicans cells, in comparison with infected animals treated with saline. Peptide modulation of host immunity upon C. albicans infection was determined by hemocyte analysis and larval histology, highlighting a different immune stimulation by the studied peptides. F11A, particularly, was the most active in eliciting nodule formation, melanization and fat body activation, leading to a better control of yeast infection. Overall, the obtained data suggest a double role for F11A, able to simultaneously target the fungus and the host immune system, resulting in a more efficient pathogen clearance.

Modulating autophagic flux via ROS-responsive targeted micelles to restore neuronal proteostasis in Alzheimer's disease

Compromised autophagy and defective lysosomal clearance significantly contribute to impaired neuronal proteostasis, which represents a hallmark of Alzheimer's disease (AD) and other age-related neurodegenerative disorders. Growing evidence has implicated that modulating autophagic flux, instead of inducing autophagosome formation alone, would be more reliable to rescue neuronal proteostasis. Concurrently, selectively enhancing drug concentrations in the leision areas, instead of the whole brain, will maximize therapeutic efficacy while reduing non-selective autophagy induction. Herein, we design a ROS-responsive targeted micelle system (TT-NM/Rapa) to enhance the delivery efficiency of rapamycin to neurons in AD lesions guided by the fusion peptide TPL, and facilitate its intracellular release via ROS-mediated disassembly of micelles, thereby maximizing autophagic flux modulating efficacy of rapamycin in neurons. Consequently, it promotes the efficient clearance of intracellular neurotoxic proteins, β-amyloid and hyperphosphorylated tau proteins, and ameliorates memory defects and neuronal damage in 3 × Tg-AD transgenic mice. Our studies demonstrate a promising strategy to restore autophagic flux and improve neuronal proteostasis by rationally-engineered nano-systems for delaying the progression of AD.

Non-canonical glutamine transamination sustains efferocytosis by coupling redox buffering to oxidative phosphorylation.

SummaryMacrophages rely on tightly integrated metabolic rewiring to clear dying neighboring cells by efferocytosis during homeostasis and disease. Here, we reveal that glutaminase (GLS) 1-mediated glutaminolysis is critical to promote apoptotic cell clearance by macrophages during homeostasis in mice. In addition, impaired macrophage glutaminolysis exacerbates atherosclerosis, a condition during which efficient apoptotic cell debris clearance is critical to limit disease progression. Gls1 expression strongly correlates with atherosclerotic plaque necrosis in patients with cardiovascular diseases. High-throughput transcriptional and metabolic profiling reveals that macrophage efferocytic capacity relies on a non-canonical transaminase pathway, independent from the traditional requirement of glutamate dehydrogenase (GLUD1) to fuel ɑ-ketoglutarate-dependent immunometabolism. This pathway is necessary to meet the unique requirements of efferocytosis for cellular detoxification and high energy cytoskeletal rearrangements. Thus, we uncover a role for non-canonical glutamine metabolism for efficient clearance of dying cells and maintenance of tissue homeostasis during health and disease in mouse and humans

Effects of Overexpression of the Egyptian Fruit Bat Innate Immune Genes on Filovirus Infections in the Host Cells.

Bats constitute a large and diverse group of mammals with unique characteristics. One of these is the ability of bats to maintain various pathogens, particularly viruses, without evidence of disease. The innate immune system has been implicated as one of the important components involved in this process. However, in contrast to the human innate immune system, little data is available for bats. In the present study we generated 23 fusion constructs of innate immune genes of Egyptian fruit bat (Rousettus aegyptiacus) with mCherry as a fluorescent reporter. We evaluated the effects of overexpressing these genes on the replication of Marburg and Ebola viruses in the Egyptian fruit bat cell line R06EJ. Both viruses were substantially inhibited by overexpression of type I, II and III interferons, as well as by DDX58 (RIG-I), IFIH1, and IRF1. Our observations suggest that the broad antiviral activity of these genes reported previously in human cells is conserved in Egyptian fruit bats and these possess anti-filovirus activities that may contribute to the efficient virus clearance.

On the function of biosynthesized cellulose as barrier against bacterial colonization of VAD drivelines

Bacterial colonization of drivelines represents a major adverse event in the implantation of left ventricular assist devices (L-VADs) for the treatment of congestive heart failure. From the external driveline interface and through the skin breach, pathogens can ascend to the pump pocket, endangering the device function and the patient’s life. Surface Micro-Engineered Biosynthesized cellulose (BC) is an implantable biomaterial, which minimizes fibrotic tissue deposition and promotes healthy tissue regeneration. The topographic arrangement of cellulose fibers and the typical material porosity support its potential protective function against bacterial permeation; however, this application has not been tested in clinically relevant animal models. Here, a goat model was adopted to evaluate the barrier function of BC membranes. The external silicone mantle of commercial L-VAD drivelines was implanted percutaneously with an intervening layer of BC to separate them from the surrounding soft tissue. End-point evaluation at 6 and 12 weeks of two separate animal groups revealed the local bacterial colonization at the different interfaces in comparison with unprotected driveline mantle controls. The results demonstrate that the BC membranes established an effective barrier against the bacterial colonization of the outer driveline interface. The containment of pathogen infiltration, in combination with the known anti-fibrotic effect of BC, may promote a more efficient immune clearance upon driveline implantation and support the efficacy of local antibiotic treatments, therefore mitigating the risk connected to their percutaneous deployment.

Airway cilia recovery post lung transplantation.

BackgroundNormally functioning airway cilia is essential for efficient mucociliary clearance to protect the airway from various insults. Impaired clearance may lead to increased risk of infections and progressive lung damage. Significant morbidity in the immediate post lung transplantation period is associated with airway infection, which we hypothesize may be caused by impaired cilia function.MethodsAirway cilia beating pattern (CBP) and frequency (CBF) were studied on brushing samples taken from above and below the transplant anastomosis of adult lung transplant recipients (n = 20) during routine bronchoscopies at 6, 12, and 26 weeks posttransplant. Bronchoaveolar Lavage (BAL) samples were also collected at each time points.ResultsAt 6 weeks posttransplant (n = 16), CBP from the donated lung showed reduced beating amplitude with the overall CBF 2.28 Hz slower than the patients' native upper airway cilia (median ± SIQR: 5.36 ± 0.93 Hz vs. 7.64 ± 0.92 Hz, p value < .001). At 12 weeks (n = 16), donor lungs CBP showed recovery with the difference in CBF reduced to 0.74 Hz (6.36 ± 1.46 Hz vs. 7.10 ± 0.86 Hz, p value < .05). Impaired cilia function was not associated with positive BAL cultures.ConclusionReduced cilia function is evident in the first 12 weeks post lung transplant, with both CBP and CBF returning to levels of function indistinguishable to the patients' upper airway cilia beyond this time.

Abstract P115: Building A Structurally Sound System To Understand SR-BI Function

The interaction of scavenger receptor BI (SR-BI) and high density lipoproteins (HDL) is the key step for the bodily removal of cholesterol. The HDL/SR-BI interaction is one of the concluding steps of the reverse cholesterol transport (RCT) pathway. In RCT, cholesterol within atherosclerotic plaques is taken up by HDL particles, which then dock on SR-BI at the surface of the liver, where cholesterol can be delivered converted into bile for excretion. Humans with mutations in the gene encoding SR-BI display elevated HDL-cholesterol levels and an increased risk of cardiovascular disease (CVD). Therefore, understanding the interaction between HDL and SR-BI is crucial to discovering ways to lower plasma cholesterol and modulate CVD risk. Due to the importance of SR-BI, the goal of these studies is to resolve a structure of functional full-length human SR-BI. We have expressed and purified full-length SR-BI using an insect cell Sf9 system. In order to assess SR-BI’s functions within this system, Sf9 cells were infected with baculovirus encoding empty vector or SR-BI, or left uninfected and plated into culture dishes. Expression of SR-BI significantly increased HDL cellular association and uptake of HDL-cholesteryl esters compared to empty vector and uninfected cells. Additionally, free cholesterol efflux was increased upon SR-BI expression. Lastly, SR-BI in Sf9 cells maintained its ability to form higher order oligomers in cells, which is crucial, as SR-BI oligomerization is important in cholesterol transport. Additionally, size exclusion chromatography shows that purified SR-BI is able to form oligomers in micelles. Lastly, using microscale thermophoresis, we demonstrated that purified SR-BI binds to its ligands (apolipoprotein A-I, holoparticle HDL, and oxidized LDL) with high affinity, regardless of the glycosylation state of SR-BI. Together, these assays represent the first steps in resolving a high-resolution structure of human full-length SR-BI and provide promise for delineating the ways in which the HDL/SR-BI relationship allows for efficient cholesterol clearance.

ATF6 is required for efficient rhodopsin clearance and retinal homeostasis in the P23H rho retinitis pigmentosa mouse model

Retinitis Pigmentosa (RP) is a blinding disease that arises from loss of rods and subsequently cones. The P23H rhodopsin knock-in (P23H-KI) mouse develops retinal degeneration that mirrors RP phenotype in patients carrying the orthologous variant. Previously, we found that the P23H rhodopsin protein was degraded in P23H-KI retinas, and the Unfolded Protein Response (UPR) promoted P23H rhodopsin degradation in heterologous cells in vitro. Here, we investigated the role of a UPR regulator gene, activating transcription factor 6 (Atf6), in rhodopsin protein homeostasis in heterozygous P23H rhodopsin (Rho+/P23H) mice. Significantly increased rhodopsin protein levels were found in Atf6−/−Rho+/P23H retinas compared to Atf6+/−Rho+/P23H retinas at early ages (~ P12), while rhodopsin mRNA levels were not different. The IRE1 pathway of the UPR was hyper-activated in young Atf6−/−Rho+/P23H retinas, and photoreceptor layer thickness was unchanged at this early age in Rho+/P23H mice lacking Atf6. By contrast, older Atf6−/−Rho+/P23H mice developed significantly increased retinal degeneration in comparison to Atf6+/−Rho+/P23H mice in all retinal layers, accompanied by reduced rhodopsin protein levels. Our findings demonstrate that Atf6 is required for efficient clearance of rhodopsin protein in rod photoreceptors expressing P23H rhodopsin, and that loss of Atf6 ultimately accelerates retinal degeneration in P23H-KI mice.

Extracellular Mitochondrial Components and Effects on Cardiovascular Disease.

Besides being powerhouses of the cell, mitochondria released into extracellular space act as intercellular signaling. Mitochondria and their components mediate cell-to-cell communication in free form or embedded in a carrier. The pathogenesis of cardiovascular disease is complex, which shows close relationship with inflammation and metabolic abnormalities. Since mitochondria sustain optimal function of the heart, extracellular mitochondria are emerging as a key regulator in the development of cardiovascular disease. In this review, we provide recent findings in the presence and forms of mitochondria transfer between cells, as well as the effects of these mitochondria on vascular inflammation and ischemic myocardium. Mitochondrial transplantation is a novel treatment paradigm for patients suffering from acute cardiovascular accident and challenges the traditional methods of mitochondria isolation.

Elaboration on the architecture of pH-sensitive surface charge-adaptive micelles with enhanced penetration and bactericidal activity in biofilms

BackgroundBiofilm formation is one of the main reasons for persistent bacterial infections. Recently, pH-sensitive copolymers have fascinated incredible attention to tackle biofilm-related infections. However, the proper incorporation of pH-sensitive segments in the polymer chains, which could significantly affect the biofilms targeting ability, has not been particularly investigated. Herein, we synthesized three types of pH-sensitive copolymers based on poly (β-amino ester) (PAE), poly (lactic-co-glycolic acid) (PLA) and polyethylene glycol (PEG), PAE-PLA-mPEG (A-L-E), PLA-PAE-mPEG (L-A-E) and PLA-PEG-PAE (L-E-A) to address this issue.ResultsThe three copolymers could self-assemble into micelles (MA-L-E, ML-A-E and ML-E-A) in aqueous medium. Compared with MA-L-E and ML-A-E, placing the PAE at the distal PEG end of PLA-PEG to yield PLA-PEG-PAE (ML-E-A) was characterized with proper triggering pH, fully biofilm penetration, and high cell membrane binding affinity. Further loaded with Triclosan (TCS), ML-E-A/TCS could efficiently kill the bacteria either in planktonic or biofilm mode. We reasoned that PAE segments would be preferentially placed near the surface and distant from the hydrophobic PLA segments. This would increase the magnitude of surface charge-switching capability, as the cationic PAE+ would easily disassociate from the inner core without conquering the additional hydrophobic force arising from covalent linkage with PLA segments, and rapidly rise to the outermost layer of the micellar surface due to the relative hydrophilicity. This was significant in that it could enable the micelles immediately change its surface charge where localized acidity occurred, and efficiently bind themselves to the bacterial surface where they became hydrolyzed by bacterial lipases to stimulate release of encapsulated TCS even a relatively short residence time to prevent rapid wash-out. In vivo therapeutic performance of ML-E-A/TCS was evaluated on a classical biofilm infection model, implant-related biofilm infection. The result suggested that ML-E-A/TCS was effective for the treatment of implant-related biofilm infection, which was proved by the efficient clearance of biofilm-contaminated catheters and the recovery of surrounding infected tissues.ConclusionsIn summary, elaboration on the architecture of pH-sensitive copolymers was the first step to target biofilm. The ML-E-A structure may represent an interesting future direction in the treatment of biofilm-relevant infections associated with acidity.Graphic abstract

The HIV-1 accessory protein Nef increases surface expression of the checkpoint receptor Tim-3 in infected CD4+ T cells

Prolonged immune activation drives the upregulation of multiple checkpoint receptors on the surface of virus-specific T cells, inducing their exhaustion. Reversing HIV-1-induced T cell exhaustion is imperative for efficient virus clearance; however, viral mediators of checkpoint receptor upregulation remain largely unknown. The enrichment of checkpoint receptors on T cells upon HIV-1 infection severely constrains the generation of an efficient immune response. Herein, we examined the role of HIV-1 Nef in mediating the upregulation of checkpoint receptors on peripheral blood mononuclear cells. We demonstrate that the HIV-1 accessory protein Nef upregulates cell surface levels of the checkpoint receptor T-cell immunoglobulin mucin domain-3 (Tim-3) and that this is dependent on Nef's dileucine motif LL164/165. Furthermore, we used a bimolecular fluorescence complementation assay to demonstrate that Nef and Tim-3 form a complex within cells that is abrogated upon mutation of the Nef dileucine motif. We also provide evidence that Nef moderately promotes Tim-3 shedding from the cell surface in a dileucine motif–dependent manner. Treating HIV-1-infected CD4+ T cells with a matrix metalloprotease inhibitor enhanced cell surface Tim-3 levels and reduced Tim-3 shedding. Finally, Tim-3-expressing CD4+ T cells displayed a higher propensity to release the proinflammatory cytokine interferon-gamma. Collectively, our findings uncover a novel mechanism by which HIV-1 directly increases the levels of a checkpoint receptor on the surface of infected CD4+ T cells.