Polymorphonuclear (PMN) leucocytes participate in acute inflammatory pathologies such as acute respiratory distress syndrome (ARDS) following traumatic injury and shock, which also activates the coagulation system systemically. Trauma can prime the PMN nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex for an enhanced respiratory burst, but the relative role of various priming agents in this process remains incompletely understood. We therefore set out to identify mediators of PMN priming during coagulation and trauma-shock and determine whether PMN reactive oxygen species (ROS) generated in this manner could influence organ injury and coagulation. Initial experiments demonstrated that PMN are primed for predominantly extracellular ROS production by products of coagulation, which was abrogated by CD88/C5a receptor(C5aR) inhibition. The importance of this was highlighted further by demonstrating that known PMN priming agents result in fractionally different amounts of extracellular versus intracellular ROS release depending on the agent used. Plasma from trauma patients in haemodynamic shock (n = 10) also primed PMN for extracellular ROS in a C5a-dependent manner, which correlated with both complement alternative pathway activation and thrombin generation. Furthermore, PMN primed by preincubation with products of blood coagulation directly caused loss of endothelial barrier function in vitro that was abrogated by C5aR blockade or NADPH oxidase inhibition. Finally, we show in a murine model of trauma-shock that p47phox knock-out (KO) mice with PMN incapable of generating ROS were protected from inflammatory end-organ injury and activated protein C-mediated coagulopathy. In summary, we demonstrate that trauma-shock and coagulation primes PMN for predominantly extracellular ROS production in a C5a-dependent manner that contributes to endothelial barrier loss and organ injury, and potentially enhances traumatic coagulopathy.

In response to DNA damage, a synthetic lethal relationship exists between the cell cycle checkpoint kinase MK2 and the tumor suppressor p53. Here, we describe the concept of augmented synthetic lethality (ASL): depletion of a third gene product enhances a preexisting synthetic lethal combination. We show that loss of the DNA repair protein XPA markedly augments the synthetic lethality between MK2 and p53, enhancing anti-tumor responses alone and in combination with cisplatin chemotherapy. Delivery of siRNA-peptide nanoplexes co-targeting MK2 and XPA to pre-existing p53-deficient tumors in a highly aggressive, immunocompetent mouse model of lung adenocarcinoma improves long-term survival and cisplatin response beyond those of the synthetic lethal p53 mutant/MK2 combination alone. These findings establish a mechanism for co-targeting DNA damageinduced cell cycle checkpoints in combination with repair of cisplatin-DNA lesions in vivo using RNAi nanocarriers, and motivate further exploration of ASL as a generalized strategy to improve cancer treatment.

BACKGROUND Trauma patients with hyperfibrinolysis and depletion of fibrinolytic inhibitors (DFIs) measured by thrombelastography (TEG) gain clot strength with TXA, but TEG results take nearly an hour. We aimed to develop an assay, plasmin TEG (P-TEG), to more expeditiously stratify risk for massive transfusion (MT), mortality, and hyperfibrinolysis. METHODS Trauma patients (N = 148) were assessed using TEG assays without exogenous additives (rapid/native), with exogenous plasmin (P-TEG) or tissue plasminogen activator (tPA TEG). The plasmin dose used does not effect healthy-control clot lysis 30 minutes after maximum amplitude (LY30) but causes shortened reaction time (R time) relative to native TEG (P-TEG R time < native TEG R time considered P-TEG negative). If P-TEG R time is greater than or equal to native TEG R time, the patient was considered P-TEG positive. Each assay's ability to predict MT, mortality, and (risk for) hyperfibrinolysis was determined. χ2 and Mann-Whitney U tests were used to compare categorical and continuous variables, respectively. Results were reported as median ± interquartile range or n (%). RESULTS Plasmin TEG provided results faster than all other assays (4.7 ± 2.5–9.1 minutes), approximately 11-fold faster than rapid-TEG (rTEG) LY30 (54.2 ± 51.1–58.1 minutes; p < 0.001). Plasmin TEG–positive patients had greater than fourfold higher MT rate (30% vs. 7%; p = 0.0015) with an area under the receiver operating characteristic curve of 0.686 (p = 0.028), greater than fourfold higher 24-hour mortality (33.3% vs. 7.8%; p = 0.0177), greater than twofold higher 30-day mortality (35% vs. 16.4%; p = 0.0483), higher rates of DFI (55% vs. 18%; p < 0.001), and a trend toward elevated D-dimer (19.9 vs. 3.3 μg/mL; p = 0.14). Plasmin TEG was associated with hyperfibrinolysis on rTEG LY30 at the 7.6% threshold (p = 0.04) but not the 3% threshold (p = 0.40). Plasmin TEG performed best in relation to DFI, with a positive predictive value of 58% and negative predictive value of 81%. When combined with tPA TEG time to maximum amplitude, P-TEG outperformed rTEG LY30 for predicting MT (area under the receiver operating characteristic curve, 0.811 vs. 0.708). CONCLUSION Within 5 minutes, P-TEG can stratify patients at highest risk for MT, mortality, and risk for hyperfibrinolysis. In composite with tPA TEG time to maximum amplitude, P-TEG outperforms rTEG LY30 for predicting MT and does so four times faster (12.7 vs. 54.1 minutes). The rapid results of P-TEG may be useful for those who practice selective TXA administration to maximize TXA's time-dependent efficacy. LEVEL OF EVIDENCE Diagnostic test, level V.