bims-heshmo 2021-10-03 papers

bims-heshmo

Biomed News

on Trauma hemorrhagic shock — molecular basis

Issue of 2021–10–03
fourteen papers selected by
Andreia Luís, Ludwig Boltzmann Institute

Deficiency of AMPKα1 Exacerbates Intestinal Injury and Remote Acute Lung Injury in Mesenteric Ischemia and Reperfusion in Mice.
Influence of Antibiotic Management on Microbial Selection and Infectious Complications After Trauma.
ICU-Admission Hyperphosphataemia Is Related to Shock and Tissue Damage, Indicating Injury Severity and Mortality in Polytrauma Patients.
Severe Traumatic Injury Induces Phenotypic and Functional Changes of Neutrophils and Monocytes.
Dexmedetomidine inhibits endoplasmic reticulum stress to suppress pyroptosis of hypoxia/reoxygenation-induced intestinal epithelial cells via activating the SIRT1 expression.
Integrated Stress Response Couples Mitochondrial Protein Translation with Oxidative Stress Control.
Potentially Functional microRNA-mRNA Regulatory Networks in Intestinal Ischemia-Reperfusion Injury: A Bioinformatics Analysis.
Construction of multifunctional porcine acellular dermal matrix hydrogel blended with vancomycin for hemorrhage control, antibacterial action, and tissue repair in infected trauma wounds.
The circRNA CNEACR regulates necroptosis of cardiomyocytes through Foxa2 suppression.
Interleukin-7 aggravates myocardial ischaemia/reperfusion injury by regulating macrophage infiltration and polarization.
Characterization of the role of integrin α5β1 in platelet function, hemostasis and experimental thrombosis.
Single Nucleotide Variant in FAS Associates With Organ Failure and Soluble Fas Cell Surface Death Receptor in Critical Illness.
AMPK-mTOR Signaling and Cellular Adaptations in Hypoxia.
Optimal intervention time of ADSCs for hepatic ischemia-reperfusion combined with partial resection injury in rats.

Int J Mol Sci. 2021 Sep 14. pii: 9911. [Epub ahead of print]22(18):

Deficiency of AMPKα1 Exacerbates Intestinal Injury and Remote Acute Lung Injury in Mesenteric Ischemia and Reperfusion in Mice.

Hannah V Hayes, Vivian Wolfe, Michael O'Connor, Nick C Levinsky, Giovanna Piraino, Basilia Zingarelli.

  Mesenteric ischemia and reperfusion (I/R) injury can ensue from a variety of vascular diseases and represents a major cause of morbidity and mortality in intensive care units. It causes an inflammatory response associated with local gut dysfunction and remote organ injury. Adenosine monophosphate-activated protein kinase (AMPK) is a crucial regulator of metabolic homeostasis. The catalytic α1 subunit is highly expressed in the intestine and vascular system. In loss-of-function studies, we investigated the biological role of AMPKα1 in affecting the gastrointestinal barrier function. Male knock-out (KO) mice with a systemic deficiency of AMPKα1 and wild-type (WT) mice were subjected to a 30 min occlusion of the superior mesenteric artery. Four hours after reperfusion, AMPKα1 KO mice exhibited exaggerated histological gut injury and impairment of intestinal permeability associated with marked tissue lipid peroxidation and a lower apical expression of the junction proteins occludin and E-cadherin when compared to WT mice. Lung injury with neutrophil sequestration was higher in AMPKα1 KO mice than WT mice and paralleled with higher plasma levels of syndecan-1, a biomarker of endothelial injury. Thus, the data demonstrate that AMPKα1 is an important requisite for epithelial and endothelial integrity and has a protective role in remote organ injury after acute ischemic events.

Keywords:  E-cadherin; occludin; remote acute lung injury; superior mesenteric artery occlusion; syndecan-1

DOI:  https://doi.org/10.3390/ijms22189911
Front Med (Lausanne). 2021 ;8 678382

Influence of Antibiotic Management on Microbial Selection and Infectious Complications After Trauma.

Cora Rebecca Schindler, Mathias Woschek, Jan-Niklas Franz, Philipp Störmann, Dirk Henrich, Ingo Marzi.

  Background: The inflammatory response and post-traumatic complications like infections play an important role in the pathophysiology of severe injuries. This study examines the microbiological aspects in anti-infective treatment of trauma patients and their inflammatory response in post-traumatic infections complications. Patients and Methods: A retrospective analysis of prospectively collected data in trauma patients (ISS ≥ 16) over a 1-year period (01/2018 to 12/2018) is provided. Patient population was stratified into severely injured patients without post-traumatic infection (inf-PT), and severely injured patients who developed an infection (inf+PT). Results: Of 114 trauma patients, 45 suffered from post-traumatic infection during the first 10 days of hospitalization. Severely injured patients with concomitant traumatic brain injury (PT+TBI) showed the highest rate of post-traumatic infection. Pro-inflammatory reaction was tracked by levels of Interleukin (IL-)6 (day 3: inf+T 190.8 ± 359.4 pg/dL > inf-PT 56.2 ± 57.7 pg/mL (mean ± SD); p = 0.008) and C-Reactive-Protein (CRP, day 3: inf+PT 15.3 mg/dL > inf-PT 6.7 mg/dL, p = 0.001) which were significantly higher in trauma patients who develop an infectious complication and showed a significant positive correlation with the occurrence of infection. The leading entity of infection was pneumonia followed by infections of the urinary tract mainly caused by gram-negative Enterobacteriaceae. 67.5% of all trauma patients received single-shot antibiosis during initial care in trauma bay. The development of secondary colonization was not relevant positively correlated with single-shot antibiosis (r = 0.013, p = 0.895) and prophylactically calculated antibiotic administration (r = 0.066, p = 0.500). Conclusion: Severely injured trauma patients have an increased risk for development of infectious complications, which mainly is pneumonia followed by infection of the urinary tract mainly caused by gram-negative Enterobacteriaceae. Based on the data in this study, the one-time antibiotic and prophylactic calculated use of antibiotics, like Cephalosporins must be critically discussed in terms of their role in the development of post-traumatic infections and microbial selection.

Keywords:  Interleukin-10; Interleukin-6; inflammation; polytrauma; severely injured patient; traumatic brain injury

DOI:  https://doi.org/10.3389/fmed.2021.678382
Diagnostics (Basel). 2021 Aug 26. pii: 1548. [Epub ahead of print]11(9):

ICU-Admission Hyperphosphataemia Is Related to Shock and Tissue Damage, Indicating Injury Severity and Mortality in Polytrauma Patients.

Christopher Rugg, Mirjam Bachler, Robert Kammerlander, Daniel Niederbrunner, Johannes Bösch, Stefan Schmid, Janett Kreutziger, Mathias Ströhle.

  Hyperphosphataemia can originate from tissue ischaemia and damage and may be associated with injury severity in polytrauma patients. In this retrospective, single-centre study, 166 polytrauma patients (injury severity score (ISS) ≥ 16) primarily requiring intensive care unit (ICU) treatment were analysed within a five-year timeframe. ICU-admission phosphate levels defined a hyperphosphataemic (>1.45 mmol/L; n = 56) opposed to a non-hyperphosphataemic group (n = 110). In the hyperphosphataemic group, injury severity was increased (ISS median and IQR: 38 (30-44) vs. 26 (22-34); p < 0.001), as were signs of shock (lactate, resuscitation requirements), tissue damage (ASAT, ALAT, creatinine) and lastly in-hospital mortality (35.7% vs. 5.5%; p < 0.001). Hyperphosphataemia at ICU admission was shown to be a risk factor for mortality (1.46-2.10 mmol/L: odds ratio (OR) 3.96 (95% confidence interval (CI) 1.03-15.16); p = 0.045; >2.10 mmol/L: OR 12.81 (CI 3.45-47.48); p < 0.001) and admission phosphate levels alone performed as good as injury severity score (ISS) in predicting in-hospital mortality (area under the ROC curve: 0.811 vs. 0.770; p = 0.389). Hyperphosphataemia at ICU admission is related to tissue damage and shock and indicates injury severity and subsequent mortality in polytrauma patients. Admission phosphate levels represent an easily feasible yet strong predictor for in-hospital mortality.

Keywords:  ICU; hyperphosphatemia; phosphate; polytrauma

DOI:  https://doi.org/10.3390/diagnostics11091548
J Clin Med. 2021 Sep 14. pii: 4139. [Epub ahead of print]10(18):

Severe Traumatic Injury Induces Phenotypic and Functional Changes of Neutrophils and Monocytes.

Andrea Janicova, Nils Becker, Baolin Xu, Marija Simic, Laurens Noack, Nils Wagner, Andreas J Müller, Jessica Bertrand, Ingo Marzi, Borna Relja.

   BACKGROUND: Severe traumatic injury has been associated with high susceptibility for the development of secondary complications caused by dysbalanced immune response. As the first line of the cellular immune response, neutrophils and monocytes recruited to the site of tissue damage and/or infection, are divided into three different subsets according to their CD16/CD62L and CD16/CD14 expression, respectively. Their differential functions have not yet been clearly understood. Thus, we evaluated the phenotypic changes of neutrophil and monocyte subsets among their functionality regarding oxidative burst and the phagocytic capacity in severely traumatized patients.
METHODS: Peripheral blood was withdrawn from severely injured trauma patients (TP; n = 15, ISS ≥ 16) within the first 12 h post-trauma and from healthy volunteers (HV; n = 15) and stimulated with fMLP and PMA. CD16dimCD62Lbright (immature), CD16brightCD62Lbright (mature) and CD16brightCD62Ldim (CD62Llow) neutrophil subsets and CD14brightCD16- (classical), CD14brightCD16+ (intermediate) and CD14dimCD16+ (non-classical) monocyte subsets of HV and TP were either directly analyzed by flow cytometry or the examined subsets of HV were sorted first by fluorescence-activated cell sorting and subsequently analyzed. Subset-specific generation of reactive oxygen species (ROS) and of E. coli bioparticle phagocytosis were evaluated.
RESULTS: In TP, the counts of immature neutrophils were significantly increased vs. HV. The numbers of mature and CD62Ldim neutrophils remained unchanged but the production of ROS was significantly enhanced in TP vs. HV and the stimulation with fMLP significantly increased the generation of ROS in the mature and CD62Ldim neutrophils of HV. The counts of phagocyting neutrophils did not change but the mean phagocytic capacity showed an increasing trend in TP. In TP, the monocytes shifted toward the intermediate phenotype, whereas the classical and non-classical monocytes became less abundant. ROS generation was significantly increased in all monocyte subsets in TP vs. HV and PMA stimulation significantly increased those level in both, HV and TP. However, the PMA-induced mean ROS generation was significantly lower in intermediate monocytes of TP vs. HV. Sorting of monocyte and neutrophil subsets revealed a significant increase of ROS and decrease of phagocytic capacity vs. whole blood analysis.
CONCLUSIONS: Neutrophils and monocytes display a phenotypic shift following severe injury. The increased functional abnormalities of certain subsets may contribute to the dysbalanced immune response and attenuate the antimicrobial function and thus, may represent a potential therapeutic target. Further studies on isolated subsets are necessary for evaluation of their physiological role after severe traumatic injury.

Keywords:  CD14; CD16; CD62L; PMA; fMLP; phagocytosis; reactive oxygen species; traumatic injury

DOI:  https://doi.org/10.3390/jcm10184139
J Bioenerg Biomembr. 2021 Sep 29.

Dexmedetomidine inhibits endoplasmic reticulum stress to suppress pyroptosis of hypoxia/reoxygenation-induced intestinal epithelial cells via activating the SIRT1 expression.

Xin Liu, Yufang Leng, Xinghua Lv, Jipeng Lv, Mengjie Zhang, Yajing Shi.

  Dexmedetomidine (Dex) can protect the intestine against ischemia/reperfusion (I/R)-induced injury. Sirtuin 1 (SIRT1) pathway, which could be activated by Dex, was reported to inhibit I/R injury. Pyroptosis plays an important role in intestinal diseases. We aimed to investigate whether Dex could attenuate pyroptosis of hypoxia/reoxygenation (H/R)-induced intestinal epithelial cells via activating SIRT1. The intestinal epithelial cell line IEC-6 with or without SIRT1 knockdown after H/R treatment was exposed to Dex, then cell viability, endoplasmic reticulum stress (ERS), apoptosis, pyroptosis, inflammatory cytokines production and SIRT1 expression were detected. Results showed that Dex treatment had no significant effect on IEC-6 cell viability but rescued the H/R-reduced cell viability. The expression of proteins involved in ERS including Grp78, Gadd153 and caspase 12 was enhanced upon H/R stimulation, but was reversely reduced by Dex. The cell apoptosis increased by H/R was also decreased by Dex. Additionally, Dex inhibited pyroptosis and inflammation, which were markedly promoted upon H/R stimulation. The expression of SIRT1, which was reduced after H/R treatment was also partially rescued by Dex. Finally, the above effects of Dex were all blocked by SIRT1 knockdown. In conclusion, Dex could inhibit H/R-induced intestinal epithelial cells ERS, apoptosis and pyroptosis via activating SIRT1 expression.

Keywords:  Dexmedetomidine; Endoplasmic reticulum stress; Intestinal ischemia reperfusion; Pyroptosis; Sirtuin1

DOI:  https://doi.org/10.1007/s10863-021-09922-3
Circulation. 2021 Sep 29.

Integrated Stress Response Couples Mitochondrial Protein Translation with Oxidative Stress Control.

Guangyu Zhang, Xiaoding Wang, Chao Li, Qinfeng Li, Yu A An, Xiang Luo, Yingfeng Deng, Thomas G Gillette, Philipp E Scherer, Zhao V Wang.

Background: The integrated stress response (ISR) is an evolutionarily conserved process to cope with intracellular and extracellular disturbances. Myocardial infarction is a leading cause of death worldwide. Coronary artery reperfusion is the most effective means to mitigate cardiac damage of myocardial infarction, which however causes additional reperfusion injury. This study aimed to investigate the role of the ISR in myocardial ischemia/reperfusion (I/R). Methods: Cardiac-specific gain- and loss-of-function approaches for the ISR were employed in vivo. Myocardial I/R was achieved by the ligation of the cardiac left anterior descending artery for 45 minutes, followed by reperfusion for different times. Cardiac function was assessed by echocardiography. Additionally, cultured H9c2 cells, primary rat cardiomyocytes, and mouse embryonic fibroblasts were used to dissect underlying molecular mechanisms. Moreover, tandem mass tag (TMT) labeling and mass spectrometry was conducted to identify protein targets of the ISR. Pharmacological means were tested to manipulate the ISR for therapeutic exploration. Results: We show that the PERK/eIF2α axis of the ISR is strongly induced by I/R in cardiomyocytes in vitro and in vivo. We further reveal a physiological role of PERK/eIF2α signaling by showing that acute activation of PERK in the heart confers robust cardioprotection against reperfusion injury. In contrast, cardiac-specific deletion of PERK aggravates cardiac responses to reperfusion. Mechanistically, the ISR directly targets mitochondrial complexes via translational suppression. We identify NDUFAF2, an assembly factor of mitochondrial complex I, as a selective target of PERK. Overexpression of PERK suppresses the protein expression of NDUFAF2 while PERK inhibition causes an increase of NDUFAF2. Silencing of NDUFAF2 significantly rescues cardiac cell survival from PERK knockdown under I/R. Further, we show that activation of PERK/eIF2α signaling reduces mitochondrial complex-derived reactive oxygen species and improves cardiac cell survival in response to I/R. Moreover, pharmacological stimulation of the ISR protects the heart against reperfusion damage, even after the restoration of occluded coronary artery, highlighting a clinical relevance for myocardial infarction treatment. Conclusions: These studies suggest that the ISR improves cell survival and mitigate reperfusion damage by selectively suppressing mitochondrial protein synthesis and reducing oxidative stress in the heart.

DOI: https://doi.org/10.1161/CIRCULATIONAHA.120.053125
J Inflamm Res. 2021 ;14 4817-4825

Potentially Functional microRNA-mRNA Regulatory Networks in Intestinal Ischemia-Reperfusion Injury: A Bioinformatics Analysis.

Zhifeng Jiang, Song Chen, Lin Zhang, Jie Shen, Ming Zhong.

   Background: Intestinal ischemia-reperfusion (II/R) injury is a common clinical complication associated with high mortality, for which microRNA (miRNA) drives potentially its pathophysiological progression. MiRNAs regulate different messenger RNAs (mRNAs). However, the regulatory network between miRNAs and mRNAs in intestinal ischemia-reperfusion injury is elusive.
Methods: We analyzed the different expression of mRNAs and miRNAs in intestinal tissues from patients from three groups (arterial group (group A), venous group (group V), control group (group C)). Common differentially expressed (Co-DE) miRNAs and differentially expressed mRNAs were acquired via concerned analyses among the three groups. Co-DE mRNAs were shared parts of target mRNAs and differentially expression mRNAs. Cytoscape was employed to construct the regulatory network between miRNAs and mRNAs. Gene Ontology (GO) analysis and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway depicted the functions and potential pathway associated with Co-DE mRNAs. Using the STRING and Cytoscape, we found critical mRNAs in the protein-protein interaction (PPI) network.
Results: The miRNA-mRNA network comprised 8 Co-DE miRNAs and 140 Co-DE mRNAs. Of note, 140 Co-DE mRNAs were targets of these 8 miRNAs, and their roles were established through the functional exploration via GO analysis and KEGG analysis. PPI network and Cytoscape revealed COL1A2, THY1, IL10, MMP2, SERPINH1, COL3A1, COL14A1, and P4HA1 as the top 8 key mRNAs.
Conclusion: This study has demonstrated a miRNA-mRNA regulatory network in intestinal ischemia-reperfusion injury, and explored the key mRNAs and their potential functions. These findings could provide new insight into prognostic markers and therapeutic targets for patients with intestinal ischemia-reperfusion injury in clinical practice.

Keywords:  bioinformatics; intestinal ischemia-reperfusion injury; microRNA; prognostic marker

DOI:  https://doi.org/10.2147/JIR.S328732
Mater Today Bio. 2021 Sep;12 100127

Construction of multifunctional porcine acellular dermal matrix hydrogel blended with vancomycin for hemorrhage control, antibacterial action, and tissue repair in infected trauma wounds.

D Cai, S Chen, B Wu, J Chen, D Tao, Z Li, Q Dong, Y Zou, Y Chen, C Bi, D Zu, L Lu, B Fang.

  Prevention of bacterial infection and reduction of hemorrhage, the primary challenges posed by trauma before hospitalization, are essential steps in prolonging the patient's life until they have been transported to a trauma center. Extracellular matrix (ECM) hydrogel is a promising biocompatible material for accelerating wound closure. However, due to the lack of antibacterial properties, this hydrogel is difficult to be applied to acute contaminated wounds. This study formulates an injectable dermal extracellular matrix hydrogel (porcine acellular dermal matrix (ADM)) as a scaffold for skin defect repair. The hydrogel combines vancomycin, an antimicrobial agent for inducing hemostasis, expediting antimicrobial activity, and promoting tissue repair. The hydrogel possesses a porous structure beneficial for the adsorption of vancomycin. The antimicrobial agent can be timely released from the hydrogel within an hour, which is less than the time taken by bacteria to infest an injury, with a cumulative release rate of approximately 80%, and thus enables a relatively fast bactericidal effect. The cytotoxicity investigation demonstrates the biocompatibility of the ADM hydrogel. Dynamic coagulation experiments reveal accelerated blood coagulation by the hydrogel. In vivo antibacterial and hemostatic experiments on a rat model indicate the healing of infected tissue and effective control of hemorrhaging by the hydrogel. Therefore, the vancomycin-loaded ADM hydrogel will be a viable biomaterial for controlling hemorrhage and preventing bacterial infections in trauma patients.

Keywords:  Bacterial infection; Extracellular matrix hydrogel; Hemostasiss; Trauma; Vancomycin

DOI:  https://doi.org/10.1016/j.mtbio.2021.100127
Cell Death Differ. 2021 Sep 29.

The circRNA CNEACR regulates necroptosis of cardiomyocytes through Foxa2 suppression.

Xiang-Qian Gao, Cui-Yun Liu, Yu-Hui Zhang, Yun-Hong Wang, Lu-Yu Zhou, Xin-Min Li, Kai Wang, Xin-Zhe Chen, Tao Wang, Jie Ju, Fei Wang, Shao-Cong Wang, Yin Wang, Zhao-Yang Chen, Kun Wang.

Circular RNAs (circRNAs) are differentially expressed in various cardiovascular disease including myocardial ischemia-reperfusion (I/R) injury. However, their functional impact on cardiomyocyte cell death, in particular, in necrotic forms of death remains elusive. In this study, we found that the level of mmu_circ_000338, a cardiac- necroptosis-associated circRNA (CNEACR), was reduced in hypoxia-reoxygenation (H/R) exposed cardiomyocytes and I/R-injured mice hearts. The enforced expression of CNEACR attenuated the necrotic form of cardiomyocyte death caused by H/R and suppressed of myocardial necrosis in I/R injured mouse heart, which was accompanied by a marked reduction of myocardial infarction size and improved cardiac function. Mechanistically, CNEACR directly binds to histone deacetylase (HDAC7) in the cytoplasm and interferes its nuclear entry. This leads to attenuation of HDAC7-dependent suppression of forkhead box protein A2 (Foxa2) transcription, which can repress receptor-interacting protein kinase 3 (Ripk3) gene by binding to its promoter region. In addition, CNEACR-mediated upregulation of FOXA2 inhibited RIPK3-dependent necrotic/necroptotic death of cardiomyocytes. Our study reveals that circRNAs such as CNEACR can regulate the cardiomyocyte necroptosis associated activity of HDACs, promotes cell survival and improves cardiac function in I/R-injured heart. Hence, the CNEACR/HDAC7/Foxa2/ RIPK3 axis could be an efficient target for alleviating myocardial damage caused by necroptotic death in ischemia heart diseases.

DOI: https://doi.org/10.1038/s41418-021-00872-2
J Cell Mol Med. 2021 Sep 28.

Interleukin-7 aggravates myocardial ischaemia/reperfusion injury by regulating macrophage infiltration and polarization.

Mengwen Yan, Yaliu Yang, Ying Zhou, Changan Yu, Rui Li, Wei Gong, Jingang Zheng.

  Interleukin (IL)-7 is known to enhance the macrophages cytotoxic activity and that macrophages play a pivotal role in the development and progression of myocardial ischaemia/reperfusion (I/R) injury. However, the effects of IL-7 on macrophages infiltration and polarization in myocardial I/R injury are currently unclear. This study aimed to evaluate the effects of the IL-7 expression on myocardial I/R injury and their relationship with macrophages. The data showed that IL-7 expression in mouse heart tissue increases following I/R injury and that IL-7 knockout or anti-IL-7 antibody treatment significantly improve I/R injury, including reduction in myocardial infarction area, a serum troponin T level decreases and an improvement in cardiac function. On the other hand, recombinant IL-7 (rIL-7) supplementation induces opposite effects and the anti-IL-7 antibody significantly reduces the cardiomyocyte apoptosis and macrophage infiltration. rIL-7 cannot directly cause apoptosis, but it can induce cardiomyocyte apoptosis through macrophages, in addition to increase the macrophages migration in vitro. Anti-IL-7 antibody affects the cytokine production in T helper (Th) 1 and Th2 cells and also promotes the macrophages differentiation to M2 macrophages. However, anti-IL-7 antibody does not reduce the M1 macrophage number, and it only increases the ratio of M2/M1 macrophages in mice heart tissues after I/R injury. Taking together, these data reveal that IL-7 plays an intensifying role in myocardial I/R injury by promoting cardiomyocyte apoptosis through the regulation of macrophage infiltration and polarization.

Keywords:  interleukin-7; ischaemia/reperfusion injury; macrophage; myocardial

DOI:  https://doi.org/10.1111/jcmm.16335
Thromb Haemost. 2021 Oct 01.

Characterization of the role of integrin α5β1 in platelet function, hemostasis and experimental thrombosis.

Emily Janus-Bell, Alexandra Yakusheva, Cyril Scandola, Nicolas Receveur, Ahmed Muhammad-Usman, Clarisse Mouriaux, Catherine Bourdon, Cécile Loubière, Anita Eckly, Yotis A Senis, Mikhail A Panteleev, Christian Gachet, Pierre Henri Mangin.

OBJECTIVE: Integrins are key regulators of various platelet functions. The pathophysiological importance of most platelet integrins has been investigated, with the exception of α5β1, a receptor for fibronectin. The aim of this study was to characterize the role of α5β1 in megakaryopoiesis, platelet function, and to determine its importance in hemostasis and arterial thrombosis.
APPROACH AND RESULTS: We generated a mouse strain deficient for integrin α5β1 on megakaryocytes and platelets (PF4Cre-α5-/-). PF4Cre-α5-/- mice were viable, fertile and presented no apparent signs of abnormality. Megakaryopoiesis appears unaltered as evidence by a normal megakaryocytes morphology and development, which is in agreement with a normal platelet count. Expression of the main platelet receptors and the response of PF4Cre-α5-/- platelets to a series of agonists were all completely normal. Adhesion and aggregation of PF4Cre-α5-/- platelets under shear flow on fibrinogen, laminin or von Willebrand factor were unimpaired. In contrast, PF4Cre-α5-/- platelets displayed a marked decrease in adhesion, activation and aggregation on fibrillar cellular fibronectin and collagen. PF4Cre-α5-/- mice presented no defect in a tail-bleeding time assay and no increase in inflammatory bleeding in a reverse passive Arthus model and a lipopolysaccharide pulmonary inflammation model. Finally, no defects were observed in three distinct experimental models of arterial thrombosis based on ferric chloride-induced injury of the carotid artery, mechanical injury of the abdominal aorta or laser-induced injury of mesenteric vessels.
CONCLUSION: In summary, this study shows that platelet integrin α5β1 is a key receptor for fibrillar cellular fibronectin but is dispensable in hemostasis and arterial thrombosis.

DOI: https://doi.org/10.1055/a-1659-6214
Crit Care Med. 2021 Sep 29.

Single Nucleotide Variant in FAS Associates With Organ Failure and Soluble Fas Cell Surface Death Receptor in Critical Illness.

Carmen Mikacenic, Pavan Bhatraju, Cassianne Robinson-Cohen, Susanna Kosamo, Alison E Fohner, Victoria Dmyterko, S Alice Long, Karen Cerosaletti, Carolyn S Calfee, Michael A Matthay, Keith R Walley, James A Russell, Jason D Christie, Nuala J Meyer, David C Christiani, Mark M Wurfel.

OBJECTIVES: Multiple organ failure in critically ill patients is associated with poor prognosis, but biomarkers contributory to pathogenesis are unknown. Previous studies support a role for Fas cell surface death receptor (Fas)-mediated apoptosis in organ dysfunction. Our objectives were to test for associations between soluble Fas and multiple organ failure, identify protein quantitative trait loci, and determine associations between genetic variants and multiple organ failure.
DESIGN: Retrospective observational cohort study.
SETTING: Four academic ICUs at U.S. hospitals.
PATIENTS: Genetic analyses were completed in a discovery (n = 1,589) and validation set (n = 863). Fas gene expression and flow cytometry studies were completed in outpatient research participants (n = 250).
INTERVENTIONS: None.
MEASUREMENTS AND MAIN RESULTS: In discovery and validation sets of critically ill patients, we tested for associations between enrollment plasma soluble Fas concentrations and Sequential Organ Failure Assessment score on day 3. We conducted a genome-wide association study of plasma soluble Fas (discovery n = 1,042) and carried forward a single nucleotide variant in the FAS gene, rs982764, for validation (n = 863). We further tested whether the single nucleotide variant in FAS (rs982764) was associated with Sequential Organ Failure Assessment score, FAS transcriptional isoforms, and Fas cell surface expression. Higher plasma soluble Fas was associated with higher day 3 Sequential Organ Failure Assessment scores in both the discovery (β = 4.07; p < 0.001) and validation (β = 6.96; p < 0.001) sets. A single nucleotide variant in FAS (rs982764G) was associated with lower plasma soluble Fas concentrations and lower day 3 Sequential Organ Failure Assessment score in meta-analysis (-0.21; p = 0.02). Single nucleotide variant rs982764G was also associated with a lower relative expression of the transcript for soluble as opposed to transmembrane Fas and higher cell surface expression of Fas on CD4+ T cells.
CONCLUSIONS: We found that single nucleotide variant rs982764G was associated with lower plasma soluble Fas concentrations in a discovery and validation population, and single nucleotide variant rs982764G was also associated with lower organ dysfunction on day 3. These findings support further study of the Fas pathway as a potential mediator of organ dysfunction in critically ill patients.

DOI: https://doi.org/10.1097/CCM.0000000000005333
Int J Mol Sci. 2021 Sep 09. pii: 9765. [Epub ahead of print]22(18):

AMPK-mTOR Signaling and Cellular Adaptations in Hypoxia.

Yoomi Chun, Joungmok Kim.

  Cellular energy is primarily provided by the oxidative degradation of nutrients coupled with mitochondrial respiration, in which oxygen participates in the mitochondrial electron transport chain to enable electron flow through the chain complex (I-IV), leading to ATP production. Therefore, oxygen supply is an indispensable chapter in intracellular bioenergetics. In mammals, oxygen is delivered by the bloodstream. Accordingly, the decrease in cellular oxygen level (hypoxia) is accompanied by nutrient starvation, thereby integrating hypoxic signaling and nutrient signaling at the cellular level. Importantly, hypoxia profoundly affects cellular metabolism and many relevant physiological reactions induce cellular adaptations of hypoxia-inducible gene expression, metabolism, reactive oxygen species, and autophagy. Here, we introduce the current knowledge of hypoxia signaling with two-well known cellular energy and nutrient sensing pathways, AMP-activated protein kinase (AMPK) and mechanistic target of rapamycin complex 1 (mTORC1). Additionally, the molecular crosstalk between hypoxic signaling and AMPK/mTOR pathways in various hypoxic cellular adaptions is discussed.

Keywords:  AMPK; hypoxia; hypoxia-inducible factor (HIF); hypoxic cellular adaptations; mTORC1

DOI:  https://doi.org/10.3390/ijms22189765
Life Sci. 2021 Sep 27. pii: S0024-3205(21)00973-5. [Epub ahead of print] 119986

Optimal intervention time of ADSCs for hepatic ischemia-reperfusion combined with partial resection injury in rats.

Chenxi Piao, Qianzhen Zhang, Jiayuan Xu, Yue Wang, Tao Liu, Haiyang Ma, Guodong Liu, Hongbin Wang.

   AIMS: Hepatic ischemia reperfusion injury (HIRI) is a complication of liver surgery and liver transplantation. Adipose-derived stem cells (ADSCs) can inhibit oxidative stress and inflammation through a paracrine effect. This study aimed to determine the optimal time window of ADSCs transplantation to restore liver function after HIRI.
MAIN METHODS: A rat model of hepatic ischemia reperfusion combined with partial hepatectomy (HIR/PH) was established. The animals were injected intravenously with 2 × 106 rat ADSCs 2 h before, immediately after, or 6 h after surgery. Liver tissues and blood samples were collected for routine histological and biochemical assays. The molecular changes were analyzed by qRT-PCR and western blotting.
KEY FINDINGS: ADSCs significantly improved liver tissue structure and decreased the levels of AST, ALT and ALP, which was indicative of functional recovery. In addition, transplantation of ADSCs immediately after operation decreased the levels of inflammation-related cytokines such as TNF-α, IL-1β and IL-6, and significantly increased the activity of antioxidant enzymes. At the same time, the expression of MDA was decreased. Mechanistically, ADSCs activated the Keap1/Nrf2 pathway in the injured liver. Transplantation of ADSCs pre- and 6 h post-operation did not significantly affect some indices such as mRNA and protein expression of HO-1, and protein expression of NQO1.
SIGNIFICANCE: Transplanting ADSCs immediately after surgery accelerated tissue repair and functional recovery of the liver by activating the Keap1/Nrf2 pathway, which inhibited hepatic inflammation and oxidative stress, and restored the hepatic microenvironment.

Keywords:  ADSCs; Hepatic ischemia reperfusion injury; Intervention time; Oxidative stress; Rats

DOI:  https://doi.org/10.1016/j.lfs.2021.119986