Secondary Necrosis Research Articles

A Nondestructive, Real-Time Annexin V Apoptosis Assay.

This chapter describes a simple, nondestructive, annexin V apoptosis detection method that can be employed in real time over a 48-h test exposure. The real-time functionality allows for temporal resolution of apoptotic and cell death responses during the test exposure and obviates the need for onerous sample preparation and time course protocols associated with other annexin V methods. Further, this technique is eminently accessible to a wide range of laboratories because it does not require flow cytometry or other cytometric methods. It was developed for use with a variety of microplate well densities and with standard multimodal plate readers. The central feature of this assay is that it continuously reports the residency status of phosphatidylserine (PS) on the exofacial surface of a cell as it is translocated from the inner membrane leaflet during the apoptotic process. This homogenous, no-wash assay is made possible by two optimized and distinct annexin V fusion proteins which contain complementing NanoBiT™ luciferase enzyme subunits, a time-released luciferase substrate, and a fluorescent membrane integrity reagent. During an apoptotic event, the luminescent signal arising from an assay well is proportional to the number of cells with PS exposure, and fluorescence intensity correlates with the degree of cell death (secondary necrosis). Conversely, untreated cells contribute negligible luminescent or fluorescent signals throughout the time course. The data collected from these assay measures provide for both standard potency determinations and kinetic characterization of dose- and agent-dependent apoptotic responses, from early through late phases.

Macrophage COX2 Mediates Efferocytosis, Resolution Reprogramming, and Intestinal Epithelial Repair.

Background and AimsPhagocytosis (efferocytosis) of apoptotic neutrophils by macrophages anchors the resolution of intestinal inflammation. Efferocytosis prevents secondary necrosis and inhibits further inflammation, and also reprograms macrophages to facilitate tissue repair and promote resolution function. Macrophage efferocytosis and efferocytosis-dependent reprogramming are implicated in the pathogenesis of inflammatory bowel disease. We previously reported that absence of macrophage cyclooxygenase 2 (COX2) exacerbates inflammatory bowel disease–like intestinal inflammation. To elucidate the underlying pathogenic mechanism, we investigated here whether COX2 mediates macrophage efferocytosis and efferocytosis-dependent reprogramming, including intestinal epithelial repair capacity.MethodsUsing apoptotic neutrophils and synthetic apoptotic targets, we determined the effects of macrophage specific Cox2 knockout and pharmacological COX2 inhibition on the efferocytosis capacity of mouse primary macrophages. COX2-mediated efferocytosis-dependent eicosanoid lipidomics was determined by liquid chromatography tandem mass spectrometry. Small intestinal epithelial organoids were employed to assay the effects of COX2 on efferocytosis-dependent intestinal epithelial repair.ResultsLoss of COX2 impaired efferocytosis in mouse primary macrophages, in part, by affecting the binding capacity of macrophages for apoptotic cells. This effect was comparable to that of high-dose lipopolysaccharide and was accompanied by both dysregulation of macrophage polarization and the inhibited expression of genes involved in apoptotic cell binding. COX2 modulated the production of efferocytosis-dependent lipid inflammatory mediators that include the eicosanoids prostaglandin I2, prostaglandin E2, lipoxin A4, and 15d-PGJ2; and further affected secondary efferocytosis. Finally, macrophage efferocytosis induced, in a macrophage COX2–dependent manner, a tissue restitution and repair phenotype in intestinal epithelial organoids.ConclusionsMacrophage COX2 potentiates efferocytosis capacity and efferocytosis-dependent reprogramming, facilitating macrophage intestinal epithelial repair capacity.

Assessment of the Immune Response to Tumor Cell Apoptosis and Efferocytosis.

Apoptotic cells are cleared from the body principally through recognition and engulfment by neighboring phagocytes, a process known as efferocytosis. During efferocytosis, phagocytes are recruited to the site/activated by "find me" signals released from apoptotic cells, precisely identify apoptotic cells by the recognition of "eat me" signals on the apoptotic cell surface, and engulf the apoptotic cells to prevent secondary necrosis and inflammation. Thus, efferocytosis is critical for tissue homeostasis in normal physiology. However, efferocytosis of apoptotic tumor cells-performed by tumor-associated macrophages-suppresses immunity within the tumor microenvironment and limits the antitumor response. This phenomenon is further exacerbated in tumor residual disease because of the high apoptotic cell burden generated by cytotoxic therapies. Blocking efferocytosis could be a powerful approach to boost tumor immunogenicity, particularly as a combination approach with cytotoxic therapies that produce many apoptotic cells, but little is currently known about the immune response to efferocytosis. Moreover, there is a dearth of in vivo models available to study the immunologic and therapeutic consequences of blocking efferocytosis in tumor residual disease.Here, we describe a model that enables in vivo studies of tumor immunology in the aftermath of cytotoxic therapy with an emphasis on the impact of efferocytosis. Orthotopic HER2+ mammary tumors are established in immune-competent mice, followed by a single administration of lapatinib, a receptor tyrosine kinase inhibitor of HER2, to the mice that induces widespread, transient apoptosis in the tumor microenvironment. In the days following lapatinib treatment, agents that block efferocytosis such as BMS-777607 are administered. Tissue is collected from cohorts of mice at day 2 (after lapatinib treatment only) to assess apoptosis, day 8 (after lapatinib treatment followed by blockade of efferocytosis) to assess the immune response to apoptosis and efferocytosis, and day 28 (after 4 consecutive weeks of treatment) to assess therapeutic efficacy. This model enables mechanistic studies of tumor immunology in residual disease as well as therapeutic efficacy studies of targeted agents that disrupt efferocytosis.

Plasma membrane perforation by GSDME during apoptosis-driven secondary necrosis

Secondary necrosis has long been perceived as an uncontrolled process resulting in total lysis of the apoptotic cell. Recently, it was shown that progression of apoptosis to secondary necrosis is regulated by Gasdermin E (GSDME), which requires activation by caspase-3. Although the contribution of GSDME in this context has been attributed to its pore-forming capacity, little is known about the kinetics and size characteristics of this. Here we report on the membrane permeabilizing features of GSDME by monitoring the influx and efflux of dextrans of different sizes into/from anti-Fas-treated L929sAhFas cells undergoing apoptosis-driven secondary necrosis. We found that GSDME accelerates cell lysis measured by SYTOX Blue staining but does not affect the exposure of phosphatidylserine on the plasma membrane. Furthermore, loss of GSDME expression clearly hampered the influx of fluorescently labeled dextrans while the efflux happened independently of the presence or absence of GSDME expression. Importantly, both in- and efflux of dextrans were dependent on their molecular weight. Altogether, our results demonstrate that GSDME regulates the passage of compounds together with other plasma membrane destabilizing subroutines.

Natural Honey as a Safe and Efficacious Alternative to Skin Grafting Post-Surgical Excision for Necrotizing Fasciitis at Primary Care Level: A Preliminary Study

Necrotizing fasciitis is a soft tissue bacterial infection that spreads rapidly resulting in the destruction of muscles, skin, and underlying tissue. Necrotizing fasciitis is defined as a fast and progressive inflammatory infection of the fascia leading to secondary necrosis of the subcutaneous tissue moving along the facial plane. Fournier gangrene is a type of necrotizing fasciitis involving the scrotum and perineal area. Patients suffering from acute necrotizing fasciitis require an effective regimen which includes surgical removal of devitalized tissues, systemic antimicrobials and mitigating underlying systemic disease processes. The burden of treating wounds following surgical debridement, on the other hand, can be challenging especially in the third world where resources are scarce resulting in suboptimal wound coverage and function. At primary care level we had the opportunity of using natural honey in 5 patients with non-healing wounds in either the lower limb or scrotum due to acute necrotizing fasciitis. This natural noninvasive approach offers a cost-effective and efficacious alternative to dermatotraction, skin grafting and negative pressure wound therapy. In these patients, the use of natural honey led to the restoration of the appearance and function of the fasciotomy wound especially in patients with co-morbidities or those refusing skin grafting due to cost, religious factors, etc. The authors present the clinical results followed by a discussion on the therapeutic properties of natural honey. This case series demonstrates the efficacy of topical raw honey as a catalyst for speeding the healing process by secondary intention thereby offering a safe and efficacious alternative for managing various wounds resulting from acute necrotizing fasciitis.

Immunological Aspects of AXL/GAS-6 in the Context of Human Liver Regeneration.

AXL and its corresponding ligand growth arrest–specific 6 (GAS‐6) are critically involved in hepatic immunomodulation and regenerative processes. Pleiotropic inhibitory effects on innate inflammatory responses might essentially involve the shift of macrophage phenotype from a pro‐inflammatory M1 to an anti‐inflammatory M2. We aimed to assess the relevance of the AXL/GAS‐6‐pathway in human liver regeneration and, consequently, its association with clinical outcome after hepatic resection. Soluble AXL (sAXL) and GAS‐6 levels were analyzed at preoperative and postoperative stages in 154 patients undergoing partial hepatectomy and correlated with clinical outcome. Perioperative dynamics of interleukin (IL)‐6, soluble tyrosine‐protein kinase MER (sMerTK), soluble CD163 (sCD163), and cytokeratin (CK) 18 were assessed to reflect pathophysiological processes. Preoperatively elevated sAXL and GAS‐6 levels predicted postoperative liver dysfunction (area under the curve = 0.721 and 0.722; P < 0.005) and worse clinical outcome. These patients failed to respond with an immediate increase of sAXL and GAS‐6 upon induction of liver regeneration. Abolished AXL pathway response resulted in a restricted increase of sCD163, suggesting a disrupted phenotypical switch to regeneratory M2 macrophages. No association with sMerTK was observed. Concomitantly, a distinct association of IL‐6 levels with an absent increase of AXL/GAS‐6 signaling indicated pronounced postoperative inflammation. This was further supported by increased intrahepatic secondary necrosis as reflected by CK18M65. sAXL and GAS‐6 represent not only potent and easily accessible preoperative biomarkers for the postoperative outcome but also AXL/GAS‐6 signaling might be of critical relevance in human liver regeneration. Refractory AXL/GAS‐6 signaling, due to chronic overactivation/stimulation in the context of underlying liver disease, appears to abolish their immediate release following induction of liver regeneration, causing overwhelming immune activation, presumably via intrahepatic immune regulation.

Induction of multiple subroutines of regulated necrosis in murine macrophages by natural BH3-mimetic gossypol.

Macrophages are critical sentinel cells armed with multiple regulated necrosis pathways, including pyroptosis, apoptosis followed by secondary necrosis, and necroptosis, and are poised to undergo distinct form(s) of necrosis for tackling dangers of pathogenic infection or toxic exposure. The natural BH3-mimetic gossypol is a toxic phytochemical that can induce apoptosis and/or pyroptotic-like cell death, but what exact forms of regulated necrosis are induced remains largely unknown. Here we demonstrated that gossypol induces pyroptotic-like cell death in both unprimed and lipopolysaccharide-primed mouse bone marrow-derived macrophages (BMDMs), as evidenced by membrane swelling and ballooning accompanied by propidium iodide incorporation and lactic acid dehydrogenase release. Notably, gossypol simultaneously induces the activation of both pyroptotic and apoptotic (followed by secondary necrosis) pathways but only weakly activates the necroptosis pathway. Unexpectedly, gossypol-induced necrosis is independent of nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3 (NLRP3) inflammasome, as neither inhibitor for the NLRP3 pathway nor NLRP3 deficiency protects the macrophages from the necrosis. Furthermore, necrotic inhibitors or even pan-caspase inhibitor alone does not or only partly inhibit such necrosis. Instead, a combination of inhibitors composed of pan-caspase inhibitor IDN-6556, RIPK3 inhibitor GSK'872 and NADPH oxidase inhibitor GKT137831 not only markedly inhibits the necrosis, with all apoptotic and pyroptotic pathways being blocked, but also attenuates gossypol-induced peritonitis in mice. Lastly, the activation of the NLRP3 pathway and apoptotic caspase-3 appears to be independent of each other. Collectively, gossypol simultaneously induces the activation of multiple subroutines of regulated necrosis in macrophages depending on both apoptotic and inflammatory caspases.

Efferocytosis in the Central Nervous System.

The effective clearance of apoptotic cells is essential for maintaining central nervous system (CNS) homeostasis and restoring homeostasis after injury. In most cases of physiological apoptotic cell death, efferocytosis prevents inflammation and other pathological conditions. When apoptotic cells are not effectively cleared, destruction of the integrity of the apoptotic cell membrane integrity, leakage of intracellular contents, and secondary necrosis may occur. Efferocytosis is the mechanism by which efferocytes quickly remove apoptotic cells from tissues before they undergo secondary necrosis. Cells with efferocytosis functions, mainly microglia, help to eliminate apoptotic cells from the CNS. Here, we discuss the impacts of efferocytosis on homeostasis, the mechanism of efferocytosis, the associations of efferocytosis failure and CNS diseases, and the current clinical applications of efferocytosis. We also identify efferocytosis as a novel potential target for exploring the causes and treatments of CNS diseases.

Apigenin Enhanced Radiation-Induced Apoptosis/Necrosis by Sensitization of LNCaP Prostate Cancer Cells to 6 MV Photon Beams.

Objective Whereas prostate cancer (PrCa) may be unresponsive or moderately responsive to radiation therapy (RT)- most common modality for treatment of PrCa- patients must receive a high dose of RT In order to achieve appropriate tumour control. However, this increase in radiation dose may lead to severe adverse effects in normal tissues. Sensitization of PrCa to radiation provides an alternate approach to improve the therapeutic efficacy of RT. This study aims to assess the radiosensitisation effect of apigenin (Api) on a prostate cancer cell line (LNCaP). Materials and Methods In this experimental study, LNCaP cells were treated with 0-80 µM Api to investigate its effect on LNCaP cell viability and determine its half-maximal inhibitory concentration (IC50). Next, the cells were divided into four groups: i. Control, ii. Cells treated with the IC50 concentration of Api, iii. Cells treated with 2 Gy ionizing radiation (IR), and cells co-treated with Api and IR. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, real-time polymerase chain reaction (PCR), and an Annexin V-FITC/PI assay were performed to assess cell survival, Bax and Bcl-2 expressions, and presence of apoptosis and necrosis. Results Api inhibited cell survival in a dose-dependent, but not time-dependent manner. Cells treated with Api had increased amounts of early apoptosis, late apoptosis, and secondary necrosis compared to the control group. This group also had decreased Bcl-2 gene expression and up-regulated Bax gene expression. Co-treatment with Api and IR significantly inhibited cell survival, and increased early apoptosis, late apoptosis and secondary necrosis compared to the other groups. There was a significant decrease in Bcl-2 gene expression along with up-regulation of Bax gene expression, and Bax/Bcl-2 ratio changes that favoured apoptosis. ConclusionApi inhibited PrCa cell survival and induced apoptosis as a single agent. In addition, Api significantly sensitized the LNCaP cells to IR and enhanced radiation-induced apoptosis.

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 &lt;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.

Mini-Review: GSDME-Mediated Pyroptosis in Diabetic Nephropathy

Pyroptosis is a recently identified type of lytic programmed cell death, in which pores form in the plasma membrane, and cells swell, rupture, and then release their contents, including inflammatory cytokines. Molecular studies indicated that pyroptosis may occur via a gasdermin D (GSDMD) and caspase-1 (Casp1) -dependent classical pathway, a GSDMD and Casp11/4/5-dependent non-classical pathway, or a gasdermin E (GSDME) and Casp3-dependent pathway. Studies of animal models and humans indicated that pyroptosis can exacerbate several complications of diabetes, including diabetic nephropathy (DN), a serious microvascular complication of diabetes. Many studies investigated the mechanism mediating the renoprotective effect of GSDMD regulation in the kidneys of patients and animal models with diabetes. As a newly discovered regulatory mechanism, GSDME and Casp3-dependent pyroptotic pathway in the progression of DN has also attracted people’s attention. Z-DEVD-FMK, an inhibitor of Casp3, ameliorates albuminuria, improves renal function, and reduces tubulointerstitial fibrosis in diabetic mice, and these effects are associated with the inhibition of GSDME. Studies of HK-2 cells indicated that the molecular and histological features of secondary necrosis were present following glucose stimulation due to GSDME cleavage, such as cell swelling, and release of cellular contents. Therefore, therapies targeting Casp3/GSDME-dependent pyroptosis have potential for treatment of DN. A novel nephroprotective strategy that employs GSDME-derived peptides which are directed against Casp3-induced cell death may be a key breakthrough. This mini-review describes the discovery and history of research in this pyroptosis pathway and reviews the function of proteins in the gasdermin family, with a focus on the role of GSDME-mediated pyroptosis in DN. Many studies have investigated the impact of GSDME-mediated pyroptosis in kidney diseases, and these studies used multiple interventions, in vitro models, and in vivo models. We expect that further research on the function of GDSME in DN may provide valuable insights that may help to improve treatments for this disease.

Efferocytosis in multisystem diseases (Review).

Efferocytosis, the phagocytosis of apoptotic cells performed by both specialized phagocytes (such as macrophages) and non-specialized phagocytes (such as epithelial cells), is involved in tissue repair and homeostasis. Effective efferocytosis prevents secondary necrosis, terminates inflammatory responses, promotes self-tolerance and activates pro-resolving pathways to maintain homeostasis. When efferocytosis is impaired, apoptotic cells that could not be cleared in time aggregate, resulting in the necrosis of apoptotic cells and release of pro-inflammatory factors. In addition, defective efferocytosis inhibits the intracellular cholesterol reverse transportation pathways, which may lead to atherosclerosis, lung damage, non-alcoholic fatty liver disease and neurodegenerative diseases. The uncleared apoptotic cells can also release autoantigens, which can cause autoimmune diseases. Cancer cells escape from phagocytosis via efferocytosis. Therefore, new treatment strategies for diseases related to defective efferocytosis are proposed. This review illustrated the mechanisms of efferocytosis in multisystem diseases and organismal homeostasis and the pathophysiological consequences of defective efferocytosis. Several drugs and treatments available to enhance efferocytosis are also mentioned in the review, serving as new evidence for clinical application.

Woundary ballistics of biological tissue’s plastic deformation on the model of ballistic plastiline using hollow point and shape-stable bullets

Introduction. Modern military conflicts make many challenges for military surgeons associated with the use of new types of weapons – hollow point bullets. The solution to this problem, firstly, depends on studying the characteristics of the terminal ballistics of such ammunition and comparing the data obtained with the characteristics of traditional weapon.&#x0D; The aim of the work is to conduct experimental modeling of the wound canal and residual wound cavity, which is formed due to plastic deformation from hollow point and non-hollow point bullets.&#x0D; Materials and methods. The studies were carried out on 40 blocks of ballistic plasticine, in each of which one shot was fired from an AKS-74 assault rifle and a ZBROYAR Z-10 carbine. Depending on the type of ammunition, the blocks of ballistic plasticine were divided into 4 groups: Group 1 – 10 blocks into which shots were made with 5.45 mm non-hollow point military cartridges with "PS" bullets with a steel core "7N6"; Group 2 (10 blocks) – 5.45x39 mm cartridges with "V-Max" hollow point bullets; Group 3 (10 blocks) – with cartridges 7.62x39 mm; Group 4 (10 blocks) – cartridges 7.62x39 mm with hollow point bullets of the "SP" type.&#x0D; Results and discussion. Only for a 5.45 mm military cartridge with "PS" bullets, both inlet and outlet bullet holes were detected in all 10 observations. When using non-hollow point bullets, the outer area of ​​the bullet inlet correlates with the caliber of the projectile (1.6 times larger when using 7.62 mm bullets). For hollow point bullets, the caliber of the projectile does not significantly affect the area of ​​the inlet (P &lt; 0.05). The expansive properties of the bullet significantly increase the area of ​​the bullet hole by 14.87-31.2 times compared to non-hollow point ammunition. Increasing the caliber of the non-hollow point bullet leads to a significant increase in the area of ​​the sagittal section of the residual wound cavity in 1.59-2.03 times; whereas the expansive properties of the bullet do not significantly affect either the perimeter or the area of ​​the sagittal section of the residual wound cavity. For non-hollow point bullets, the volume of the residual wound cavity is more correlated with the caliber of the bullet (increases by 3.36 times); whereas for an hollow point bullet, its caliber has a smaller effect on the volume of the residual cavity (increases by 1.37 times). The expansive properties of the bullet affect the volume of the residual wound cavity in two ways: for 5.45 mm bullets the residual wound cavity increases 1.49 times, for 7.62 mm bullets it decreases 1.65 times. The use of hollow point bullets of 7.62 mm leads to greater collateral damage (zone of secondary necrosis, molecular shock) due to the scattering of the kinetic energy of the bullet to the elastic deformation of near-woundary tissues compared to non-hollow point analogues. The use of 5.45 mm expansive bullets leads to the formation of a larger volume of irreversible damage due to plastic deformation compared to non-hollow point analogues.&#x0D; Conclusions. The resulting model of plastic deformation of soft tissues, depending on the type of modern small arms, showed the dependence of the spatial configuration of the inlet bullet hole, residual wound cavity and deformation and fragmentation of the bullet on the caliber of the cartridge and its expansive properties.

Physiological Roles of Apoptotic Cell Clearance: Beyond Immune Functions

The clearance of apoptotic cells is known to be a critical step in maintaining tissue and organism homeostasis. This process is rapidly/promptly mediated by recruited or resident phagocytes. Phagocytes that engulf apoptotic cells have been closely linked to the release of anti-inflammatory cytokines to eliminate inflammatory responses. Defective clearance of apoptotic cells can cause severe inflammation and autoimmune responses due to secondary necrosis of apoptotic cells. Recently accumulated evidence indicates that apoptotic cells and their clearance have important physiological roles in addition to immune-related functions. Herein, we review the current understanding of the mechanisms and fundamental roles of apoptotic cell clearance and the beneficial roles of apoptotic cells in physiological processes such as differentiation and development.

ATRXLoss Increases Sensitivity to Proton Radiotherapy Compared to X-Ray Radiotherapy in Glioma Stem Cells via Secondary Necrosis

Glioblastoma Multiforme (GBM-Grade IV) is the most aggressive form of glioma in the USA carrying only a 15 month median survival time. Although IDH1R132H is traditionally associated with improved glioma patient survival and clinical response to chemotherapy, astrocytoma (LGG) patients also harbor ATRXLoss, an inactivation of the ATRX chromatin remodeling protein previously shown to impair DNA damage repair via non-homologous end joining. The recent discovery of glioma stem cells (GSCs), a subpopulation of chemoradioresistant, self-renewable, tumor initiating cells known to promote tumor recurrence, presents a new target for therapeutic intervention. However, the mechanisms by which ATRXLoss contributes to GSC proton radiotherapy (PRT) sensitivity, a more tumor specific and cytotoxic form of radiation therapy than conventional X-rays (XRT), are not well understood. We hypothesize that ATRXLoss impairs GSC post-radiation viability by promoting secondary necrosis to a higher extent after PRT than XRT.Isogenic TS543-ATRXWT and TS543-ATRXLoss patient derived glioma cells were cultured as neurospheres and treated with 2-8 Gy XRT or PRT. GSC viability was quantified using the CellTiterGlo 3D assay 12 days after irradiation. The Annexin V apoptosis and necrosis assay was conducted every 8 hours up to 72 hours after irradiation. GSC self-renewal, based on neurosphere formation frequency, was quantified using extreme limiting dilution analysis (ELDA).ATRXLoss significantly decreased TS543 GSC viability after 2-8 Gy radiation therapy compared to ATRXWT (Unpaired t-test with Welsh's correction and Holm-Sidak's Multiple Comparisons Test P < 0.0001). TS543-ATRXLoss also significantly decreased GSC self-renewal over TS543-ATRXWT when subject to either 6 Gy PRT or XRT (Pairwise Pr (> χ2) < 0.01). Interestingly, PRT significantly reduced GSC viability to a higher extent than XRT in TS543-ATRXLoss GSCs, which demonstrates the effectiveness of PRT to treat ATRXLoss gliomas. Follow up studies confirmed that ATRXLoss sensitizes TS543 GSCs more extensively to the cytotoxic effects of PRT compared to XRT via the upregulation of secondary necrosis at 72 hours post-irradiation (Two-way ANOVA with Tukey's post-hoc Multiple Comparisons Test P < 0.0001).We conclude that ATRXLoss substantially contributes to PRT sensitivity in GSCs, thereby supporting the benefits of PRT for astrocytoma patients. Our future experiments will further elucidate the biological mechanisms by which ATRXLoss confers PRT sensitivity, especially via dsDNA damage.A.A.Garces: None. L.Bronk: None. K. Bhat: None. D.R.Grosshans: None.

Limited Surgery and Conformal Photon Radiation Therapy for Pediatric Craniopharyngioma: Long-Term Results From the RT1 Protocol

To estimate long-term disease control and selected complications for children and adolescents with craniopharyngioma after treatment with limited surgery and conformal photon radiation therapy (CRT) at a single institution. To benchmark outcomes to guide new treatment approaches, interventions, and surveillance.A total of 101 pediatric patients with craniopharyngioma were prospectively enrolled on a phase II single institutional protocol beginning 1998. Surgery was individualized to treat presenting symptoms, reduce the irradiated volume, and avoid diabetes insipidus (DI). CRT (54Gy) was administered using a 1.0cm or 0.5cm clinical target volume margin and MRI was used during treatment to monitor the targeted volume. Patients were followed in the radiation oncology clinic for 10 years. Follow-up included serial MRI/MRA and a battery of tests to measure CNS effects.Tumor progression was experienced by 20 patients. The median time to progression was 5.1 years. Death occurred in 12 patients who experienced tumor progression (n = 6), complications related to tumor or treatment (n = 5) or both (n = 1). With a median follow-up of 14.94 years for survivors, the 10-year estimates (± SE) of progression-free, event-free, and overall-survival were 78.84% ± 4.10%, 77.12% ± 4.19%, and 96.02% ± 1.95%, respectively. The 10-year cumulative incidence (± SE) of secondary tumor (1.99% ± 1.40%), secondary malignant tumor (1.0% ± 1.0%), necrosis (1.98% ± 1.39%), vasculopathy (8.47% ± 2.90%), and other permanent neurologic deficits (8.28% ± 3.37%) were estimated with tumor progression, secondary malignancy and death as competing risks. Three patients required revascularization surgery. Surgery was characterized by tumor-directed procedures: none (n = 5), single (n = 50), and multiple (n = 46). Excluding those who presented with DI (n = 7), there was no difference in prevalence of DI by number of procedures; however, the single procedure group had a higher incidence of DI after craniotomy compared to bur hole procedures (P < 0.001). Salvage therapy was successful in 13 patients using combinations of surgery and radiosurgery. Including frontline and salvage therapy, the incidence of diabetes insipidus (62%), growth hormone (82%), thyroid hormone (92%), adrenal hormone (89%), and sex hormone (81%) replacement therapies were individually assessed. Seizures that required treatment were observed in 19% and aspirin therapy was prescribed in 23%.Limited surgery and CRT using photons results in excellent tumor control. Pediatric patients with craniopharyngioma experience a wide range of complications. The incidence and severity of complications may be further reduced by improving the type and extent of surgery procedures, newer methods of irradiation, and improving patient compliance with follow-up.

HMGB1 signaling phosphorylates Ku70 and impairs DNA damage repair in Alzheimer\u2019s disease pathology

DNA damage is increased in Alzheimer’s disease (AD), while the underlying mechanisms are unknown. Here, we employ comprehensive phosphoproteome analysis, and identify abnormal phosphorylation of 70 kDa subunit of Ku antigen (Ku70) at Ser77/78, which prevents Ku70-DNA interaction, in human AD postmortem brains. The abnormal phosphorylation inhibits accumulation of Ku70 to the foci of DNA double strand break (DSB), impairs DNA damage repair and eventually causes transcriptional repression-induced atypical cell death (TRIAD). Cells under TRIAD necrosis reveal senescence phenotypes. Extracellular high mobility group box 1 (HMGB1) protein, which is released from necrotic or hyper-activated neurons in AD, binds to toll-like receptor 4 (TLR4) of neighboring neurons, and activates protein kinase C alpha (PKCα) that executes Ku70 phosphorylation at Ser77/78. Administration of human monoclonal anti-HMGB1 antibody to post-symptomatic AD model mice decreases neuronal DSBs, suppresses secondary TRIAD necrosis of neurons, prevents escalation of neurodegeneration, and ameliorates cognitive symptoms. TRIAD shares multiple features with senescence. These results discover the HMGB1-Ku70 axis that accounts for the increase of neuronal DNA damage and secondary enhancement of TRIAD, the cell death phenotype of senescence, in AD.

Ultrastructural changes in giant cell tumor of bone cultured cells exposed to quercetin

ABSTRACT Giant cell tumor of bone (GCTB) is a primary bone tumor that affects skeletally mature people and whose main treatment is surgical. Because there are few pharmacological alternatives for the treatment of this tumor to find other molecules or compounds that could be potential therapeutic agents is desirable. Quercetin is a flavonoid with described antitumoral effect in different types of cancer cell lines that could be a possible option in GCTB treatment. However, there is no literature about the effect of quercetin on GCTB. In the present paper, we reported the ultrastructural changes in GCTB cells exposed to quercetin and also determined the expression of RIP1K, Caspase 3 and Caspase 8 on the exposed cells. For this purpose, GCTB sample was obtained from one patient and cultured. Quercetin affected all the histological components of the GCTB. The ultrastructural changes consisted mainly in necroptosis, autophagocytosis and secondary necrosis. This is the first report about quercetin effects on giant cell tumor of bone cultured cells. Further studies in other models could be done to support the use of quercetin as a complementary treatment in giant cell tumor of bone. Abbreviations: Giant cell tumor of bone (GCTB); transmission electron microscopy (TEM); reverse transcription – polymerase chain reaction (RT-PCR); receptor interacting protein kinase 1 (RIP1K); Dulbecco’s Modified Eagle’s Medium (DMEM).

Local Trends of Antibiotic Prescriptions for Necrotizing Fasciitis Patients in Two Tertiary Care Hospitals in Central Malaysia.

Background: Necrotizing fasciitis (NF) is a rapidly progressive inflammatory infection of the soft tissue (also known as the fascia) with a secondary necrosis of the subcutaneous tissues, leading to a systemic inflammatory response syndrome (SIRS), shock and eventually death despite the availability of current medical interventions. The clinical management of this condition is associated with a significant amount of morbidity with a high rate of mortality. The prognosis of the disease is affected by multiple factors, which include the virulence of the causative pathogen, local host immunity, local wound factors and empirical antibiotics used. The local trends in the prescription of empirical antibiotics are often based on clinical practice guidelines (CPG), the distribution of the causative microorganism and the cost-effectiveness of the drug. However, there appears to be a paucity of literature on the empirical antibiotic of choice when dealing with necrotizing fasciitis in the clinical setting. This paper will outline common causative microorganisms and current trends of prescription in two tertiary centres in Central Malaysia. Methods: This was a cross-sectional study using retrospective data of patients treated for NF collected from two tertiary care hospitals (Hospital Seremban and Hospital Ampang) in Central Malaysia. A total of 420 NF patients were identified from the five years of retrospective data obtained from the two hospitals. Results: The top three empirical antibiotics prescribed are ampicillin + sulbactam (n = 258; 61.4%), clindamycin (n = 55; 13.1%) and ceftazidime (n = 41; 9.8%). The selection of the antibiotic significantly impacts the outcome of NF. The top three causative pathogens for NF are Streptococcus spp. (n = 79; 18.8%), Pseudomonas aeruginosa (n = 61; 14.5%) and Staphylococcus spp. (n = 49; 11.7%). The patients who received antibiotics had 0.779 times lower chances of being amputated. Patients with a lower laboratory risk indicator for necrotizing fasciitis (LRINEC) score had 0.934 times lower chances of being amputated. Conclusions: In this study, the most common empirical antibiotic prescribed was ampicillin + sulbactam followed by clindamycin and ceftazidime. The antibiotics prescribed lower the risk of having an amputation and, hence, a better prognosis of the disease. Broad-spectrum empirical antibiotics following surgical debridement reduce the mortality rate of NF.

Специфічність діабетичної кардіоміопатії за наявності коморбідних серцево-судинних захворювань: клініко-ультраструктурні дослідження

Актуальність. Концепція про діабетичну кардіоміопатію вперше була запропонована С. Рублер та співавт. понад 100 років тому, але цей діагноз рідко використовується клініцистами через існування, переважно в пацієнтів із цукровим діабетом (ЦД), таких коморбідних захворювань, як ішемічна хвороба серця (ІХС) і гіпертонічна хвороба. Різноманітні механізми спричинюють патогенез діабетичної кардіоміопатії, але її специфічні ознаки досі остаточно не встановлені. Мета дослідження — з’ясувати ультраструктурні особливості ремоделювання кардіоміоцитів, характерні для діабетичної кардіоміопатії, за наявності коморбідної ІХС та артеріальної гіпертензії (АГ). Матеріали і методи. Були порівняні результати клінічного обстеження та ультраструктурного дослідження експрес-некропсій та періопераційних біопсій міокарда в 25 пацієнтів із ЦД 2-го типу за наявності супутньої АГ та ІХС. Результати. Виявлені ультраструктурні особливості гібернації кардіоміоцитів, характерні для ЦД 2-го типу, відмінні від їх гібернації за наявності ІХС та АГ. З’ясовано, що гібернація кардіоміоцитів за ЦД виникає вже на ранніх стадіях захворювання, ще до розвитку АГ та ІХС, тобто за відсутності гіпертрофії кардіоміоцитів та їх оглушеності, характерних для серцево-судинних захворювань. Висновки. Діабетична кардіоміопатія виникає в результаті дисметаболічних і мікроциркуляційних розладів, що призводить до гібернації кардіоміоцитів. Тригерами розвитку діабетичної кардіоміопатії є декомпенсація ЦД і серцево-судинні захворювання. Гіберновані кардіоміоцити гинуть шляхом апоптозу або вторинного некрозу, що обумовлює трансформацію діастолічної дисфункції лівого шлуночка в систолічну.