Premature Degradation Research Articles

Thymosin α-1 does not correct F508del-CFTR in cystic fibrosis airway epithelia.

In cystic fibrosis (CF), deletion of phenylalanine 508 (F508del) in the cystic fibrosis transmembrane conductance regulator (CFTR) anion channel causes misfolding and premature degradation. Considering the numerous effects of the F508del mutation on the assembly and processing of CFTR protein, combination therapy with several pharmacological correctors is likely to be required to treat CF patients. Recently, it has been reported that thymosin α-1 (Tα-1) has multiple beneficial effects that could lead to a single-molecule-based therapy for CF patients with F508del. Such effects include suppression of inflammation, improvement in F508del-CFTR maturation and gating, and stimulation of chloride secretion through the calcium-activated chloride channel (CaCC). Given the importance of such a drug, we aimed to characterize the underlying molecular mechanisms of action of Tα-1. In-depth analysis of Tα-1 effects was performed using well-established microfluorimetric, biochemical, and electrophysiological techniques on epithelial cell lines and primary bronchial epithelial cells from CF patients. The studies, which were conducted in 2 independent laboratories with identical outcome, demonstrated that Tα-1 is devoid of activity on mutant CFTR as well as on CaCC. Although Tα-1 may still be useful as an antiinflammatory agent, its ability to target defective anion transport in CF remains to be further investigated.

Breakdown properties of aged low voltage cross-linked polyethylene insulated cable

In this study, the electrical breakdown strength tests were performed on low voltage insulation material, crosslinked polyethylene (XLPE) insulated cable rated at 0.6/1 (1.2) kV. In Malaysia, this type of cable was found to have premature degradation within three to five years of service. The objective of this experiment is to study the characteristic of XLPE used as the insulation material of the aged cable. The allowable maximum operating temperature of this cable is at 90 °C. New cables of different manufacturers were tested and a degraded cable taken from field was used as a reference sample. The thermal consequences on each cable were compared. XLPE sheets sliced from the cable insulations were prepared as the test samples. New samples were heated to a temperature of 90 °C to accelerate the ageing process in an oven. An electrical breakdown tests were carried out to assist the evaluation of the degradation on the unaged and aged cables. It has been shown by the experiment that the electrical properties of the aged XLPE of low voltage cable for both manufacturers were greatly affected when exposed to the heat. This can be considered as defect to the manufacturing process because the insulation layers could possibly be made of a substandard material, that fails to perform according to the specification.

Oxidation Resistance and Microstructure Evaluation of a Polymer Derived Ceramic (PDC) Composite Coating Applied onto Sintered Steel.

Powder metallurgy is a competitive technology to produce ferrous near net shape parts for diverse engineering applications. However, their inherent porosity increases the susceptibility to oxidation and sealing their surface is mandatory to avoid premature degradation. Alongside, polymer derived ceramics (PDCs), such as silicon-carbonitride, have drawn attention concerning their high temperature and chemical stability. However, PDCs undergo volume shrinkage during ceramization that leads to defect formation. The shrinkage can be compensated by the addition of fillers, which are also capable of tailoring the ceramic resulting properties. This work evaluates the processing of PDC-based coatings loaded with ZrO2 and glass fillers to compensate for the shrinkage, densify the coating and seal the sintered steel surface. Therefore, polymeric slurries were sprayed onto sintered steel substrates, which were pyrolyzed at different temperatures for microstructural and oxidation resistance evaluation. Microstructural modifications caused by the enhanced glass viscous flow during pyrolysis at 800 °C resulted in more homogeneous, dense and protective coatings, which reduced the mass gain up to 40 wt% after 100 h of oxidation at 450 °C in air in comparison to the uncoated substrate. Moreover, no macrocracks or spallation were detected, confirming the feasibility of PDC composite barrier coatings for sintered steels.

Biodegradable hyaluronan hydrogel coatings on acellular dermis grafts—A potential strategy to improve biologic graft durability in hernia repair application

Biologic grafts used in hernia repair undergo rapid cellular infiltration and remodeling, but their premature degradation often results in hernia recurrence. We hypothesize that a temporary barrier that prevents infiltration of acute inflammatory cells into the graft during the initial 4 weeks of implantation could mitigate graft degradation. The purpose of this study is to design tyramine-substituted hyaluronan (THA) hydrogel coatings with tunable degradation properties, as a means to develop a resorbable barrier for human acellular dermis grafts (HADM). THA plugs prepared at different cross-linking densities, by varying cross-linking agent concentration (0.0001-0.0075% H2 O2 ), demonstrated varying rates of in vitro degradation (25 U/mL hyaluronidase, 48 h). Based on these results, HADM grafts were coated with THA at three cross-linking densities (0.0001%, 0.00075%, and 0.003% H2 O2 ) and THA coating degradation was evaluated in vitro (25 U/mL hyaluronidase, 48 h) and in vivo (rat intraperitoneal implantation, 1-4 weeks). THA coatings degraded in vitro and in vivo with the lowest cross-linking density (0.0001% H2 O2 ), generally showing greater degradation as evidenced by significant decrease in coating cross-sectional area. However, all three coatings remained partially degraded after 4 weeks of in vivo implantation. Alternate strategies to accelerate in vivo degradation of THA coatings are required to allow investigation of the study hypothesis. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B:2664-2672, 2019.

Comparative development of staminate and pistillate flowers in the dioecious cactus Opuntia robusta.

PCD role in unisexual flowers. The developmental processes underlying the transition from hermaphroditism to unisexuality are key to understanding variation and evolution of floral structure and function. A detailed examination of the cytological and histological patterns involved in pollen and ovule development of staminate and pistillate flowers in the dioecious Opuntia robusta was undertaken, and the potential involvement of programmed cell death in the abortion of the sex whorls was explored. Flowers initiated development as hermaphrodites and became functionally unisexual by anthesis. Female individuals have pistillate flowers with a conspicuous stigma, functional ovary, collapsed stamens and no pollen grains. Male individuals have staminate flowers, with large yellow anthers, abundant pollen grains, underdeveloped stigma, style and an ovary that rarely produced ovules. In pistillate flowers, anther abortion resulted from the premature degradation of the tapetum by PCD, followed by irregular deposition of callose wall around the microsporocytes, and finally by microspore degradation. In staminate flowers, the stigma could support pollen germination; however, the ovaries were reduced, with evidence of placental arrest and ovule abortion through PCD, when ovules were present. We demonstrate that PCD is recruited in both pistillate and staminate flower development; however, it occurs at different times of floral development. This study contributes to the understanding of the nature of the O. robusta breeding system and identifies developmental landmarks that contribute to sexual determination in Cactaceae.

Formulation and evaluation of deflazacort loaded mucoadhesive microsphere for colon drug delivery system

Irritable bowel disease is very common colon disease. Deflazacort is one of the best drug with clinical activity against Irritable bowel disease. Microsphere system are effectively protect drugs against premature degradation, to localize drug molecules at the target site of action and to control the time and rate of release. Mucoadhesive microspheres enhance the bioavailability of orally given drugs by lengthened contact time of drug with the intestinal mucosa. The main disadvantage of these microspheres is adherence to the substrate by non-specific interaction. To overcome this limitation, microspheres are prepared by emulsification method to treat irritable bowel disease. Chitosan microspheres were prepared by Ionotropic Gelation method. Microspheres were coated with Eudragil S using solvent evaporation method.
 Keywords: Deflazacort, Mucoadhesive, Microspheres, Irritable bowel disease

Functionalization of AuMSS nanorods towards more effective cancer therapies

The application of nanoparticles as selective drug delivery platforms arises as one the most promising therapeutic strategies in the biomedical field. Such systems can encapsulate drugs, prevent its premature degradation, transport and promote the drugs specific delivery to the target site. Among the different nanostructures, gold-core mesoporous silica shell (AuMSS) nanorods have been one of the most explored due to their unique physical and chemical properties. The mesoporous silica biocompatibility, high surface area that can be easily functionalized, tubular pores that can store the drugs, conjugated with the intrinsic capacity of gold nanorod to absorb near-infrared radiation, allows the combination of hyperthermia (i.e., photothermal effect) with drug delivery, making them a nanoplatforms with a huge potential for cancer therapy. Nevertheless, the successful application of AuMSS nanoparticles as an effective cancer nanomedicine is hindered by the uncontrolled release of the therapeutic payloads, limited blood circulation time and unfavorable pharmacokinetics. In this review, an overview of the modifications performed to improve the AuMSS nanorods application in nanomedicine is provided, highlighting the practical approaches that enhanced the AuMSS nanorods targeting, responsiveness to different stimuli, and blood circulation time. Further, the basics of AuMSS nanorods synthesis procedures, general properties, and its application in cancer therapy are also described.

Dispersible hydrolytically sensitive nanoparticles for nasal delivery of thyrotropin releasing hormone (TRH)

Nose-to-brain delivery of drugs is affected by nanoparticles (NPs) deposited on the olfactory surface and absorbed directly into the brain. Thyrotropin releasing hormone (TRH), a water soluble drug used for treating suicidal patients, was incorporated into a fast degrading poly(sebacic anhydride) (PSA) NPs. NPs were prepared by a solvent-antisolvent process under strict anhydrous environment to obtain high TRH loading and to avoid premature PSA degradation and TRH release. PSA and TRH were dissolved in a mixture of dichloromethane and ethanol and added dropwise to a dispersion of mannitol particles in heptane as an antisolvent. Mannitol powder was included in the antisolvent, so that formed NPs adhered to the mannitol microparticles for easy isolation and immediate dispersion in water prior to use. The size, surface charge, and morphology of the TRH-PSA NPs were determined using dynamic light scattering (DLS), zeta-potential, and Scanning Electron Microscopy (SEM), respectively. The NPs prepared were uniform and spherical of ~250 nm. Further, the in vitro release profile of TRH from NPs lasted for 12 h with most TRH released within the first hour in water. Concentration dependent cell toxicity studies revealed low toxicity level at low concentrations of the NPs. Surface adsorption of the NPs was also uniform on the cell surface as examined through the odyssey near infrared fluorescence (NIR) images using Indocyanine green (ICG). The NPs are designed to enable direct delivery to the olfactory epithelium using a refillable nasal atomizer that deposits mist onto the olfactory neuro-epithelium.

Peptide-biofunctionalization of biomaterials for osteochondral tissue regeneration in early stage osteoarthritis: challenges and opportunities.

Osteoarthritis is a degenerative joint disease characterized by the progressive deterioration of articular cartilage, synovial inflammation and changes in periarticular and subchondral bone, being a leading cause of disability. Conventional treatments present several side effects and can involve the use of painkillers and non-steroidal anti-inflammatory drugs. In this sense, researchers have shifted the focus of new therapeutics to biomolecular agents and/or their combination with cells. However, the efficacy of these molecules is dependent on their metabolization which can differ according to the administration route and delivery approach. Consequently, a tissue engineering strategy comprising the use of biomaterials can provide support for neo-tissue osteochondral repair/regeneration whilst conferring proper mechanical and functional features as well as protecting biomolecular agents from premature degradation. The current strategies and challenges used in biomaterials functionalization with peptides that can mimic ECM proteins or other natural soluble biomolecules, important to induce the complex interactions between cells and the ECM, are discussed herein. Many opportunities for treating OA are being explored by means of peptide-biofunctionalization of biomaterials which can be designed to be recognizable, induce differentiation, prevent infection, degrade at an intended rate or act as drug delivery systems for controlled release or even as simple triggers of cell behavior.

Assessment of Compression strength of Concrete Columns Confined with Basalt Fibre Reinforced Polymer

Columns are the main load bearing element of a structure. Therefore, columns have an important function in many structures and can be vulnerable to exceptional loads. As structures age, the columns often have a lack of transverse reinforcement, which is unable to provide sufficient confinement to the concrete core or to prevent buckling of the longitudinal reinforcement which causes premature strength degradation of the column. The primary objectives of this research are to investigate the behaviour of axially loaded concrete columns confined with an obscure material in civil engineer for strengthening, basalt fibre reinforced polymer jacket (BFRP). This paper presents a test program that was done on concrete blocks confined with basalt fibre reinforced polymer (BFRP) and examination of its compression strength. The test results show that the strength enhancement of the concrete blocks consists of more ductile behaviour.

Konvencionalni i napredni adjuvansi u formulacijama vakcina - mineralni adsorbenti, nanočestični nosači i sistemi tipa mikroigala

In the era of modern vaccinology, limited immunogenicity of the most commonly used antigens has enforced the use of various adjuvants in vaccine formulations to achieve desired immune response. Aluminum-containing adjuvants have been, historically, the most widely used mineral immunostimulants, generally regarded as safe to use in human vaccines. The great academic progress in inorganic (nano)materials synthesis, structure control and functionalization design has led to a growing interest in innovative adjuvants such as clays, mesoporous silica nanoparticles, zinc oxide, iron oxide and iron hydroxide nanoparticles, etc. On the other hand, there has been an intention to use specific nanoparticulated antigen delivery systems, such as nanoemulsions, in order to protect antigens from premature proteolytic degradation and/or to improve antigen immunogenicity by facilitating antigen uptake and processing by antigen presenting cells. Simultaneously, numerous research efforts have been focused on the development of innovative technologies for antigen delivery into the skin (such as microneedles), with the aim to improve vaccine efficacy alongside with enhanced patient adherence, particularly in children population (noninvasive or minimally invasive administration). Therefore, this review deals with each of these approaches in more detail, with the special emphasis on examples of their use in vaccine formulations as well as on the factors influencing their efficacy and safety.

Investigation and mitigation of premature bearing degradation in motor drive system

Pulse width modulated (PWM) variable frequency drives (VFDs) are commonly adopted in modern control of electro-mechanical drive systems. The use of insulated-gate bipolar transistor (IGBT) and higher switching frequencies has improved the efficiency of the motor drive systems significantly but they also cause high frequency common-mode (CM) currents in the motor bearings. Hence, new drive installations failed prematurely within months, which resulted in unnecessary downtime. Mitigation techniques such as CM filter and motor shaft grounding ring are possible solutions to prevent this kind of premature failure. In this paper, using a 5.5 kW motor drive system as a case study, the cause of bearing degradation is investigated and the various mitigation techniques are carefully evaluated.

A Comprehensive Review on PLGA-based Nanoparticles used for Rheumatoid Arthritis

Worldwide, Nanotechnology is frequently used for various applications in fields of medical science and therapeutics. However, biodegradable nanoparticles can improve the therapeutic value of various H2O soluble / insoluble drugs by improving solubility, bioavailability, retention time and protection of premature degradation of drugs in biological environment. In comparison to general Nanoparticles (NPs), encapsulation process with polymeric NPs are considered to be more fruitful and advanced as it provides better patient compliance. Since three decades through extensive research, polymers were first introduced as biodegradable or naturally dissolved surgical device. Current scenario utilizes polymeric based nanoparticles for the treatment of various ailments. Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease related to joints which hampers the normal life by exhibiting extra-articular manifestations. In-spite of major advances in drug therapies, still limitations are pervading with severe side effects in case of conventional drug delivery systems. Although different polymers are used for the preparation of Nanoparticles, utilization of USFDA and EMA approved Poly (lactic-co-glycolic acid) (PLGA) has gained much more popularity due to its unique features like low cytotoxicity, biocompatibility, biodegradability, targeted drug delivery, possibility of sustained release formulation and long biomedical applications. Nevertheless, researchers reveled that for targeted drug delivery, key factor involved is the persistance of NPs in systemic circulation of body. However, conventional NPs are rapidly opsonized and cleared through macrophages (fixed MPS) which is considered as foremost challenge in preparing these type of formulations. Hence, in order to overcome these problems, surface modification of conventional NPs with different molecules are needed so as to increase the circulation time and persistance of NPs in the blood. Furthermore, this review explores various key design parameters of RA targeted PLGA- based nanotechnology strategies in improving the treatment of rheumatoid arthritis. It comprehensively addresses various issues related to PLGA-based nanoparticles along with its method of preparation, surface modification and characterization techniques. Unlike usual drugs, nanoparticle drug delivery system aims at providing better patient compliance by delivering the drug to inflamed synovium by reducing systemic side effects.

Harmonic Investigation of Compact Fluorescent Lamps Low Energy Consumption Lamps of Cameroonian Market

This article presents a study of compact fluorescent lamps (CFLs) low energy consumption lamps found in the Cameroonian market. The current obtained in the experimental setup has been analyzed in Matlab Simulink. The results obtained show that the THD of different lamps does not respect the standard IEC-61000-3-2. These values increase with the power of lamps. Spectral analysis of these lamps shows that the probable cause of their premature degradation results from the effects of harmonics on the capacitors. This degradation is all more precocious as the rank and the concerned THDi is great. That’s why 75 W lamps are more sensitive than others.

Biomaterial-induced multinucleated giant cells express proinflammatory signaling molecules: A histological study in humans.

The biomaterials physicochemical characteristics influence their cellular reaction, degradation and regenerative capacities. Macrophages and multinucleated giant cells (MNGCs) are observed in the augmentation area of biomaterials. This study, for the first time, evaluated the polarization pattern of macrophages and MNGCs in response to two different bone substitute materials (synthetic bone substitute material [SBSM] = NanoBone vs. xenogeneic bone substitute material [XBSM] = Bio-Oss) in human bone biopsies compared to non-augmented bone (control). Histomorphometrical analysis of the polarization in proinflammatory (M1) and anti-inflammatory (M2) cells was performed using different immunohistochemical markers: CD-68 = macrophages; CCR-7 and Cox-2 (M1) and CD-206 and CD-163 (M2) and tartrate-resistant acid phosphatase (TRAP). The macrophage polarization pattern in SBSM showed a significantly higher number of M1 cells than did XBSM and non-augmented bone. XBSM induced a significantly higher number of CD-206-positive macrophages than SBSM did. No significant difference was found between XBSM and the non-augmented bone. MNGCs expressed CD-68 and TRAP. In both test-groups, MNGCs showed a high proinflammatory character (CCR-7 and Cox-2-positive) and their number in the SBSM group was significantly higher than that of XBSM. The tissue distribution showed a significantly low percentage of the remaining biomaterial in SBSM compared to XBSM. Within the limitations of this study, these findings show that MNGCs exhibit a rather proinflammatory character and lead to biomaterial degradation, once they are induced in a high number. The premature degradation of bone substitute materials is compensated with a high percentage of connective tissue and not new bone formation. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 780-790, 2019.

In HPV-Positive HNSCC Cells, Functional Restoration of the p53/p21 Pathway by Proteasome Inhibitor Bortezomib Does Not Affect Radio- or Chemosensitivity

Human papillomavirus (HPV) associated squamous cell carcinomas of the head and neck region (HPV+ HNSCCs) harbor diverging biological features as compared to classical noxa-induced (HPV−) HNSCC. One striking difference between subtypes is that the tumor suppressor gene TP53 is usually not mutated in HPV+ HNSCCs. However, p53 is inhibited by viral oncoprotein E6, leading to premature proteasomal degradation. We asked whether bortezomib (BZM), a clinically approved inhibitor of the proteasome, can functionally restore p53 and investigated in how far this will result in an enhanced radio- or chemosensitivity of HPV+ HNSCC cell lines. For all four HPV+ cell lines tested, BZM led to functional restoration of p53 and transactivation of downstream protein p21. In HPV+ cells, BZM also restored the radiation-induced p53/p21 transactivation. Consistently, in HPV+ cells, a restored G1 arrest as well as enhanced apoptosis were seen when BZM was given prior to irradiation (IR) or cisplatin (CDDP). BZM alone reduced the clonogenic survival of both HPV− and HPV+ cells. However, if BZM was combined with IR or CDDP, BZM did not significantly enhance radio- or chemosensitivity of HPV+ or HPV− HNSCC cell lines.

WORLD AND DOMESTIC EXPERIENCE OF BIOETHANOL PRODUCTION

The paper presents an overview of bioetanol production technologies. It is noted that world fuel ethanol production in 2017 amounted to more than 27,000 million gallons (80 million tons). Eight countries, namely the USA, Brazil, the EU, China, Canada, Thailand, Argentina, India, together produce about 98% of bioethanol. In Ukraine, the volume of bioethanol production by alcoholic factories in recent years has been gradually increasing and amounted to 2,992.8 ths. dal in 2017. The production of ethanol as an additive to gasoline, with regard to the raw materials used, as well as the corresponding technologies, is historically divided into three generations. The first generation of biofuels produced from food crops rich in sugar or starch is currently dominant.
 Production of advanced biofuels from non-food crop feedstocks is limited. Output is anticipated to remain modest in the short term, as progress is needed to improve technology readiness. The main stages of bioethanol production from lignocellulosic raw materials are pre-treatment, enzymatic hydrolysis and fermentation. The pre-treatment process aims to reduce of sizes of raw material particles, provision of the components exposure (hemicellulose, cellulose, starch), provision of better access for the enzymes (in fermentative hydrolysis) to the surface of raw materials, and reduction of crystallinity degree of the cellulose matrix. The pre-treatment process is a major cost component of the overall process. The pre-treatment process is highly recommended as it gives subsequent or direct yield of the fermentable sugars, prevents premature degradation of the yielded sugars, prevents inhibitors formation prior hydrolysis and fermentation, lowers the processing cost, and lowers the demand of conventional energy in general. From the perspective of efficiency, promising methods of pre-treatment of lignocellulosic raw materials to hydrolysis are combined methods combining mechanical, chemical and physical mechanisms of influence on raw materials. One method that combines several physical effects on a treated substance is the discrete-pulsed energy input (DPIE) method. The DPIE method can be applied in the pre- treatment of lignocellulosic raw material in the technology bioethanol production for intensifying the process and reducing energy consumption. Ref. 15, Fig. 2.

Maize male sterile 33 encodes a putative glycerol-3-phosphate acyltransferase that mediates anther cuticle formation and microspore development

BackgroundThe anther cuticle, which is primarily composed of lipid polymers, is crucial for pollen development and plays important roles in sexual reproduction in higher plants. However, the mechanism underlying the biosynthesis of lipid polymers in maize (Zea mays. L.) remains unclear.ResultsHere, we report that the maize male-sterile mutant shrinking anther 1 (sa1), which is allelic to the classic mutant male sterile 33 (ms33), displays defective anther cuticle development and premature microspore degradation. We isolated MS33 via map-based cloning. MS33 encodes a putative glycerol-3-phosphate acyltransferase and is preferentially expressed in tapetal cells during anther development. Gas chromatography-mass spectrometry revealed a substantial reduction in wax and cutin in ms33 anthers compared to wild type. Accordingly, RNA-sequencing analysis showed that many genes involved in wax and cutin biosynthesis are differentially expressed in ms33 compared to wild type.ConclusionsOur findings suggest that MS33 may contribute to anther cuticle and microspore development by affecting lipid polyester biosynthesis in maize.

CYT01B, a Novel RAD51 Inhibitor, Act Synergistically with Both Targeted and Chemotherapeutic Anti-Cancer Agents

We have developed CYT01B, a novel RAD51 inhibitor, that sensitizes cells to Activation Induced Cytidine Deaminase (AID) activity. In cancer cells, AID causes significant genotoxic stress through DNA replication fork damage, creating a dependency upon the homologous recombination repair factor, RAD51, for survival. CYT01B acts by destabilizing RAD51 focus formation, leading to its premature nuclear export and degradation. We have shown CYT01B to be effective in AID expressing cells, however, we had yet to address if inhibition of RAD51 could act as a sensitizer to current therapeutics. To determine potential drug combinations, a matrix study was performed with CYT01B (concentration range of 20nM to 5μM) and six different targeted agents or chemotherapeutics in three different cell lines: ARPE19/HPV16 (HPV immortalized normal epithelial cell line), KYSE-70 (head and neck cancer cell line) and Daudi (Burkitt's Lymphoma cell line). We then used the Bliss Independence model to determine drug interaction (synergistic, independent, or antagonistic). The compounds tested were the ATR inhibitor VE-822 (concentration range of 39nM to 2.5μM), the RPA inhibitor TDRL-505 (concentration range of 39nM to 5μM), the proteasome inhibitor Bortezomib (concentration range of 39nM to 2.5μM), Carboplatin (concentration range of 156nM to 10μM), and the PARP inhibitors Olaparib and Niraparib (concentration range of 78nM to 5μM). With VE-822 we observed synergy in the KYSE-70 cell line with ambiguous results in Daudi and ARPE19/HPV16. In ARPE19/HPV16 cell line, synergy was observed with CYT01B at 39nM with all concentrations of VE-822, but antagonistic activity was seen at the high and low concentrations. In Daudi, antagonism was observed at the highest concentrations of VE-822, but an additive effect was noted at the lower concentrations of VE-822. Antagonism was observed at all concentrations of CYT01B with TDRL-505 in both Daudi and ARPE19/HPV16. Weak synergy was observed in KYSE70 cells at 156 and 312nM CYT01B. CYT01B was synergistic with Bortezomib in ARPE19/HPV16 at all concentrations but was consistently antagonistic in KYSE-70 and Daudi. We observed synergy with carboplatin in all cell lines, with the effect consistent across the full concentration range in the cancer cell lines. Synergy was also observed consistently across the full concentration range in all three cell lines with both PARP inhibitors. However, Olaparib showed a stronger synergistic effect than Niraparib. These data suggest that CYT01B may be effective as a combinatorial therapy with platinum based chemotherapeutics and with PARP and ATR inhibitors. Overall, we conclude that there is significant potential for RAD51 inhibition to be used in future combination cancer treatment strategies and warrants further exploration in vivo. DisclosuresMaclay:Cyteir Therapeutics: Employment. Vacca:Cyteir Therapeutics: Consultancy. McComas:Cyteir Therapeutics: Consultancy. Castro:Cyteir Therapeutics: Consultancy. Day:Cyteir Therapeutics: Employment. Mills:Cyteir Therapeutics: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees.

Trivalent RING Assembly on Retroviral Capsids Activates TRIM5 Ubiquitination and Innate Immune Signaling

SummaryTRIM5 is a RING domain E3 ubiquitin ligase with potent antiretroviral function. TRIM5 assembles into a hexagonal lattice on retroviral capsids, causing envelopment of the infectious core. Concomitantly, TRIM5 initiates innate immune signaling and orchestrates disassembly of the viral particle, yet how these antiviral responses are regulated by capsid recognition is unclear. We show that hexagonal assembly triggers N-terminal polyubiquitination of TRIM5 that collectively drives antiviral responses. In uninfected cells, N-terminal monoubiquitination triggers non-productive TRIM5 turnover. Upon TRIM5 assembly on virus, a trivalent RING arrangement allows elongation of N-terminally anchored K63-linked ubiquitin chains (N-K63-Ub). N-K63-Ub drives TRIM5 innate immune stimulation and proteasomal degradation. Inducing ubiquitination before TRIM5 assembly triggers premature degradation and ablates antiviral restriction. Conversely, driving N-K63 ubiquitination after TRIM5 assembly enhances innate immune signaling. Thus, the hexagonal geometry of TRIM5’s antiviral lattice converts a capsid-binding protein into a multifunctional antiviral platform.