ARIH2 is essential for embryogenesis, and its hematopoietic deficiency causes lethal activation of the immune system.

The E3 ligase ARIH2 has an unusual structure and mechanism of elongating ubiquitin chains. To understand its physiological role, we generated gene-targeted mice deficient in ARIH2. ARIH2 deficiency resulted in the embryonic death of C57BL/6 mice. On a mixed genetic background, the lethality was attenuated, with some mice surviving beyond weaning and then succumbing to an aggressive multiorgan inflammatory response. We found that in dendritic cells (DCs), ARIH2 caused degradation of the inhibitor IκBß in the nucleus, which abrogated its ability to sequester, protect and transcriptionally coactivate the transcription factor subunit p65 in the nucleus. Loss of ARIH2 caused dysregulated activation of the transcription factor NF-κB in DCs, which led to lethal activation of the immune system in ARIH2-sufficent mice reconstituted with ARIH2-deficient hematopoietic stem cells. Our data have therapeutic implications for targeting ARIH2 function.

Gasdermin D inhibition prevents multiple organ dysfunction during sepsis by blocking NET formation.

Multiple organ dysfunction is the most severe outcome of sepsis progression and is highly correlated with a worse prognosis. Excessive neutrophil extracellular traps (NETs) are critical players in the development of organ failure during sepsis. Therefore, interventions targeting NET release would likely effectively prevent NET-based organ injury associated with this disease. Herein, we demonstrate that the pore-forming protein gasdermin D (GSDMD) is active in neutrophils from septic humans and mice and plays a crucial role in NET release. Inhibition of GSDMD with disulfiram or genic deletion abrogated NET formation, reducing multiple organ dysfunction and sepsis lethality. Mechanistically, we demonstrate that during sepsis, activation of the caspase-11/GSDMD pathway controls NET release by neutrophils during sepsis. In summary, our findings uncover a novel therapeutic use for disulfiram and suggest that GSDMD is a therapeutic target to improve sepsis treatment.

TREM-1 as a Marker of Multiple Organ Failure in Cardiac Surgery.

Systemic inflammatory response syndrome (SIRS) frequently accompanies early postoperative period after cardiac surgery and in some cases is complicated by multiple organ failure (MOF). Inherited variation in the innate immune response genes (e.g., TREM1) is among the major factors determining the development of SIRS and the risk of MOF. This research was aimed to study whether the polymorphisms within the TREM1 gene are associated with MOF after the coronary artery bypass graft (CABG) surgery. Here we enrolled 592 patients who underwent CABG surgery in the Research Institute for Complex Issues of Cardiovascular Diseases (Kemerovo, Russia) and documented 28 cases of MOF. Genotyping was performed by allele-specific PCR using TaqMan probes. In addition, we measured serum soluble triggering receptor expressed on myeloid cells 1 (sTREM-1) using enzyme-linked immunosorbent assay. Five polymorphisms (rs1817537, rs2234246, rs3804277, rs7768162 andrs4711668) within the TREM1 gene were significantly associated with MOF. Patients with MOF had higher serum sTREM-1 as compared with those without MOF at both pre- and post-intervention stages. Serum sTREM-1 was associated with the rs1817537,rs2234246 and rs3804277 polymorphisms within the TREM1 gene. Minor alleles within the TREM1 gene define the level of serum sTREM-1 and are associated with MOF after CABG surgery.

Whole-exome Sequencing Identifies SLC52A1 and ZNF106 Variants as Novel Genetic Risk Factors for (Early) Multiple-organ Failure in Acute Pancreatitis.

OBJECTIVE: The aim of this study was to identify genetic variants associated with early multiple organ failure (MOF) in acute pancreatitis. SUMMARY BACKGROUND DATA: MOF is a life-threatening complication of acute pancreatitis, and risk factors are largely unknown, especially in early persistent MOF. Genetic risk factors are thought to enhance severity in complex diseases such as acute pancreatitis. METHODS: A 2-phase study design was conducted. First, we exome sequenced 9 acute pancreatitis patients with early persistent MOF and 9 case-matched patients with mild edematous pancreatitis (phenotypic extremes) from our initial Dutch cohort of 387 patients. Secondly, 48 candidate variants that were overrepresented in MOF patients and 10 additional variants known from literature were genotyped in a replication cohort of 286 Dutch and German patients. RESULTS: Exome sequencing resulted in 161,696 genetic variants, of which the 38,333 non-synonymous variants were selected for downstream analyses. Of these, 153 variants were overrepresented in patients with multiple-organ failure, as compared with patients with mild acute pancreatitis. In total, 58 candidate variants were genotyped in the joined Dutch and German replication cohort. We found the rs12440118 variant of ZNF106 to be overrepresented in patients with MOF (minor allele frequency 20.4% vs 11.6%, Padj=0.026). Additionally, SLC52A1 rs346821 was found to be overrepresented (minor allele frequency 48.0% vs 42.4%, Padj= 0.003) in early MOF. None of the variants known from literature were associated.Conclusions: This study indicates that SLC52A1, a riboflavin plasma membrane transporter, and ZNF106, a zinc finger protein, may be involved in disease progression toward (early) MOF in acute pancreatitis.

miR-126 ameliorates multiple organ dysfunction in septic rats by regulating the differentiation of Th17/Treg.

BACKGROUND: The most common cause of death in sepsis is MODS. We hope that miR-126 can regulate the differentiation of Th17/Treg, reduce the infiltration of inflammatory factors in peripheral blood and various organs and tissues, and improve organ function and prognosis in sepsis. METHODS AND RESULTS: Septic rat model was established by cecal perforation and ligation. miR-126 mimic and inhibitor were used to intervene sepsis. The experimental results showed that miR-126 mimic reduced the differentiation of Th17 and increased the differentiation of Treg in septic rats, resulting in the TNF-α, IL-6 and IL-17 were decreased in peripheral blood, the infiltration levels of TNF-α, IL-6 and IL-17 were decreased in lung, liver and kidney, the tissue damage degree of lung, liver and kidney were weakened, and the corresponding histopathological score decreased. Finally, the survival rate of septic rats was increased. However, after using miR-126 inhibitor, the levels of inflammatory factors and the degree of multiple organ injury in septic rats increased in varying degrees, and the prognosis of septic rats was worse. CONCLUSION: This study confirmed that miR-126 can regulate the differentiation of Th17/Treg, change the infiltration of inflammatory factors in peripheral blood, lung, liver and kidney of septic rats, alleviate MODS, and improve the organ function and prognosis of septic rats.

Gene signature for the prediction of the trajectories of sepsis-induced acute kidney injury.

BACKGROUND: Acute kidney injury (AKI) is a common complication in sepsis. However, the trajectories of sepsis-induced AKI and their transcriptional profiles are not well characterized. METHODS: Sepsis patients admitted to centres participating in Chinese Multi-omics Advances In Sepsis (CMAISE) from November 2020 to December 2021 were enrolled, and gene expression in peripheral blood mononuclear cells was measured on Day 1. The renal function trajectory was measured by the renal component of the SOFA score (SOFArenal) on Days 1 and 3. Transcriptional profiles on Day 1 were compared between these renal function trajectories, and a support vector machine (SVM) was developed to distinguish transient from persistent AKI. RESULTS: A total of 172 sepsis patients were enrolled during the study period. The renal function trajectory was classified into four types: non-AKI (SOFArenal = 0 on Days 1 and 3, n = 50), persistent AKI (SOFArenal > 0 on Days 1 and 3, n = 62), transient AKI (SOFArenal > 0 on Day 1 and SOFArenal = 0 on Day 3, n = 50) and worsening AKI (SOFArenal = 0 on Days 1 and SOFArenal > 0 on Day 3, n = 10). The persistent AKI group showed severe organ dysfunction and prolonged requirements for organ support. The worsening AKI group showed the least organ dysfunction on day 1 but had higher serum lactate and prolonged use of vasopressors than the non-AKI and transient AKI groups. There were 2091 upregulated and 1,902 downregulated genes (adjusted p < 0.05) between the persistent and transient AKI groups, with enrichment in the plasma membrane complex, receptor complex, and T-cell receptor complex. A 43-gene SVM model was developed using the genetic algorithm, which showed significantly greater performance predicting persistent AKI than the model based on clinical variables in a holdout subset (AUC: 0.948 [0.912, 0.984] vs. 0.739 [0.648, 0.830]; p < 0.01 for Delong's test). CONCLUSIONS: Our study identified four subtypes of sepsis-induced AKI based on kidney injury trajectories. The landscape of host response aberrations across these subtypes was characterized. An SVM model based on a gene signature was developed to predict renal function trajectories, and showed better performance than the clinical variable-based model. Future studies are warranted to validate the gene model in distinguishing persistent from transient AKI.

Potential of circulating lncRNA CASC2 as a biomarker in reflecting the inflammatory cytokines, multi-organ dysfunction, disease severity, and mortality in sepsis patients.

BACKGROUND: Long noncoding RNA (lncRNA) cancer susceptibility candidate gene 2 (CASC2) inhibits inflammation and multi-organ dysfunction in various ways. The present study was intended to explore the potency of blood lncRNA CASC2 as a biomarker for sepsis management. METHODS: Totally, 184 sepsis patients and 30 healthy controls were enrolled. The reverse transcription-quantitative polymerase chain reaction was used to detect lncRNA CASC2 expression in peripheral blood mononuclear cell samples from the subjects. Mortality during 28 days was recorded in sepsis patients. RESULTS: LncRNA CASC2 was decreased in sepsis patients [median (interquartile range [IQR]): 0.473 (0.241-0.773)] by comparison to healthy controls [median (IQR): 1.019 (0.676-1.685)] (p < 0.001). In sepsis patients, lncRNA CASC2 was negatively correlated with Acute Physiology and Chronic Health Evaluation II (APACHE II) (p = 0.001), Sequential Organ Failure Assessment (SOFA) (p < 0.001), SOFA-respiratory system (p = 0.010), SOFA-coagulation (p = 0.020), SOFA-liver (p = 0.019), and SOFA-renal (p = 0.010) scores, but was not related to SOFA-nervous (p = 0.466) and SOFA-cardio vascular system (p = 0.059) scores. Additionally, lncRNA CASC2 was negatively related to tumor necrosis factor-α (p = 0.024), interleukin (IL)-1ß (p = 0.013), and IL-17A (p = 0.002), but was not linked to IL-6 (p = 0.112) or IL-10 (p = 0.074). Furthermore, lncRNA CASC2 was lower in sepsis deaths [median (IQR): 0.286 (0.166-0.475)] than in survivors [median (IQR): 0.534 (0.296-0.811)] (p < 0.001). Simultaneously, Kaplan-Meier (KM) curve analysis also observed that lncRNA CASC2 was inversely related to accumulating mortality in sepsis patients (p = 0.003). While lncRNA CASC2 could independently predict lower mortality risk. CONCLUSION: Circulating lncRNA CASC2 inadequacy indicates the release of inflammatory cytokines, severe multi-organ injuries, and increased mortality in sepsis patients.

Blood long non-coding RNA intersectin 1-2 is highly expressed and links with increased Th17 cells, inflammation, multiple organ dysfunction, and mortality risk in sepsis patients.

BACKGROUND: Long non-coding RNA intersectin 1-2 (lnc-ITSN1-2) exacerbates inflammation and promotes T-helper (Th) cell differentiation, also serves as a biomarker in critical illness diseases. However, its clinical role in sepsis remains obscure. Hence, the study aimed to explore the relationship of lnc-ITSN1-2 with Th cells, inflammation, disease severity, multiple organ dysfunction, and mortality risk in sepsis. METHODS: Peripheral blood mononuclear cells (PBMC) were isolated from 95 sepsis patients and 50 health controls, followed by lnc-ITSN1-2 evaluation using RT-qPCR. PBMC Th1, Th17 cells and their secreted cytokines in serum were detected by flow cytometry and ELISA, respectively. RESULTS: Lnc-ITSN1-2 in sepsis patients was higher than it in health controls (Z = -7.328, p < 0.001). Lnc-ITSN1-2 correlated with increased interferon-gamma (p = 0.009), Th17 cells (p = 0.022), and interleukin-17A (p = 0.006), but not Th1 cells (p = 0.169) in sepsis patients. Moreover, lnc-ITSN1-2 had a positive connection with C-reactive protein (p = 0.001), acute pathologic and chronic health evaluation (APACHE) II (p = 0.024), and sequential organ failure assessment (SOFA) scores (p = 0.022). Regarding SOFA subscales, lnc-ITSN1-2 linked with elevated respiratory system score (p = 0.005), cardiovascular system score (p = 0.007), and renal system score (p = 0.004) but no other subscales. Besides, lnc-ITSN1-2 had an increasing trend, but no statistical difference, in septic deaths compared to survivors (Z = -1.852, p = 0.064). CONCLUSION: Lnc-ITSN1-2 reflects sepsis progression and unfavorable prognosis to some extent, which may serve as a potential biomarker to improve the management of sepsis patients.

Evaluating the potency of blood long noncoding RNA PVT1 as candidate biomarker reflecting inflammation, multiple organ dysfunction, and mortality risk in sepsis patients.

OBJECTIVE: Long noncoding RNA plasmacytoma variant translocation 1 (lnc-PVT1) promotes septic inflammation and organ injuries via multiple ways, while its clinical engagement in sepsis management is indistinct. This study aimed to investigate its relationship with inflammation, multiple organ dysfunction, and mortality risk in sepsis patients. METHODS: Sepsis patients and age-/gender-matched healthy controls were enrolled; their lnc-PVT1 expression in plasma were detected by RT-qPCR. For sepsis patients only, the inflammatory cytokine levels (tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, and IL-17A) in plasma were detected by ELISA. According to the survival data during 28-day follow-up, sepsis patients were divided into sepsis survivors and sepsis deaths. RESULTS: Lnc-PVT1 expression was increased in sepsis patients (N = 157) compared with healthy controls (N = 80) (p < 0.001). In sepsis patients, lnc-PVT1 was linked with higher acute physiology and chronic health evaluation II (APACHEII) score (p = 0.001), total sequential organ failure assessment (SOFA) score, and its most subitems (SOFA-respiratory system, SOFA-coagulation, SOFA-liver, SOFA-cardiovascular system, and SOFA-renal system scores) (all p < 0.01), but not SOFA-nervous system score (p = 0.091); it did not relate to primary infection sites either (p = 0.204). Furthermore, lnc-PVT1 correlated with increased C-reactive protein, TNF-α, IL-1ß, and IL-17 in sepsis patients (all p < 0.01). Additionally, lnc-PVT1 expression was higher in sepsis deaths than that in sepsis survivors (p < 0.001), following receiver-operating characteristic curve disclosed that lnc-PVT1 predicted 28-day septic mortality risk (area under the curve: 0.789, 95% confidence interval: 0.702-0.875). CONCLUSION: Circulating lnc-PVT1 exhibits the potential as a biomarker in sepsis patients to inform inflammation, multiple organ dysfunction, and mortality risk.

Mitochondrial DNA as a Candidate Marker of Multiple Organ Failure after Cardiac Surgery.

Assess the level of mitochondrial DNA depending on the presence of multiple organ failure in patients after heart surgery. The study included 60 patients who underwent surgical treatment of valvular heart disease using cardiopulmonary bypass. Uncomplicated patients were included in the 1st group (n = 30), patients with complications and multiple organ failure (MOF) were included in the 2nd group (n = 30). Serum mtDNA levels were determined by quantitative real-time polymerase chain reaction with fluorescent dyes. Mitochondrial DNA gene expression did not differ between group before surgery. Immediately after the intervention, cytochrome B gene expression was higher in the group with MOF, and it remained high during entire follow-up period. A similar trend was observed in cytochrome oxidase gene expression. Increased NADH levels of gene expressions during the first postoperative day were noted in both groups, the expression showed tendency to increase on the third postoperative day. mtDNA gene expression in the "MOF present" group remained at a higher level compared with the group without complications. A positive correlation was reveled between the severity of MOF according to SOFA score and the level of mtDNA (r = 0.45; p = 0.028) for the end-point "First day". The ROC analysis showed that mtDNA circulating in plasma (AUC = 0.605) can be a predictor of MOF development. The level of mtDNA significantly increases in case of MOF, irrespective of its cause. (2) The expression of mtDNA genes correlates with the level of MOF severity on the SOFA score.

Expression of MicroRNAs in Sepsis-Related Organ Dysfunction: A Systematic Review.

Sepsis is a critical condition characterized by increased levels of pro-inflammatory cytokines and proliferating cells such as neutrophils and macrophages in response to microbial pathogens. Such processes lead to an abnormal inflammatory response and multi-organ failure. MicroRNAs (miRNA) are single-stranded non-coding RNAs with the function of gene regulation. This means that miRNAs are involved in multiple intracellular pathways and thus contribute to or inhibit inflammation. As a result, their variable expression in different tissues and organs may play a key role in regulating the pathophysiological events of sepsis. Thanks to this property, miRNAs may serve as potential diagnostic and prognostic biomarkers in such life-threatening events. In this narrative review, we collect the results of recent studies on the expression of miRNAs in heart, blood, lung, liver, brain, and kidney during sepsis and the molecular processes in which they are involved. In reviewing the literature, we find at least 122 miRNAs and signaling pathways involved in sepsis-related organ dysfunction. This may help clinicians to detect, prevent, and treat sepsis-related organ failures early, although further studies are needed to deepen the knowledge of their potential contribution.

FAM96A knock-out promotes alternative macrophage polarization and protects mice against sepsis.

Sepsis is an intractable clinical syndrome characterized by organ dysfunction when the body over-responds to an infection. Sepsis has a high fatality rate and lacks effective treatment. Family with sequence similarity 96 member A (FAM96A) is an evolutionarily conserved protein with high expression in the immune system and is related to cytosolic iron assembly and tumour suppression; however, research has been rarely conducted on its immune functions. Our study found that Fam96a-/- mice significantly resisted lesions during sepsis simulated by caecal ligation and puncture (CLP) or endotoxicosis models. After a challenge with lipopolysaccharide (LPS) or infection, Fam96a-/- mice exhibited less organ damage, longer survival and better bacterial clearance with decreased levels of proinflammatory cytokines. While screening several subsets of immune cells, FAM96A-expressing macrophages as the key cell type inhibited sepsis development. In-vivo macrophage depletion or adoptive transfer experiments abrogated significant differences in the survival of sepsis between Fam96a-/- and wild-type mice. Results of the bone marrow-derived macrophage (BMDM) polarization experiment indicated that FAM96A deficiency promotes the transformation of uncommitted monocytes/macrophages (M0) into M2 macrophages, secreting fewer proinflammatory cytokines. FAM96A may mediate an immunometabolism shift - from oxidative phosphorylation (OXPHOS) to glycolysis - in macrophages during sepsis, mirrored by reactive oxygen species (ROS) and glucose uptake. These data demonstrate that FAM96A regulates inflammatory response and provide a novel genomic insight for sepsis treatment.

SARS-CoV-2 infection: molecular mechanisms of severe outcomes to suggest therapeutics.

Introduction:The year 2020 was defined by the 29,903 base pairs of RNA that codes for the SARS-CoV-2 genome. SARS-CoV-2 infects humans to cause COVID-19, spreading from patient-to-patient yet impacts patients very divergently.Areas covered: Within this review, we address the known molecular mechanisms and supporting data for COVID-19 clinical course and pathology, clinical risk factors and molecular signatures, therapeutics of severe COVID-19, and reinfection/vaccination. Literature and published datasets were reviewed using PubMed, Google Scholar, and NCBI SRA tools. The combination of exaggerated cytokine signaling, pneumonia, NETosis, pyroptosis, thrombocytopathy, endotheliopathy, multiple organ dysfunction syndrome (MODS), and acute respiratory distress syndrome (ARDS) create a positive feedback loop of severe damage in patients with COVID-19 that impacts the entire body and may persist for months following infection. Understanding the molecular pathways of severe COVID-19 opens the door for novel therapeutic design. We summarize the current insights into pathology, risk factors, secondary infections, genetics, omics, and drugs being tested to treat severe COVID-19.Expert opinion: A growing level of support suggests the need for stronger integration of biomarkers and precision medicine to guide treatment strategies of severe COVID-19, where each patient has unique outcomes and thus require guided treatment.

Sepsis is associated with mitochondrial DNA damage and a reduced mitochondrial mass in the kidney of patients with sepsis-AKI.

BACKGROUND: Sepsis is a life-threatening condition accompanied by organ dysfunction subsequent to a dysregulated host response to infection. Up to 60% of patients with sepsis develop acute kidney injury (AKI), which is associated with a poor clinical outcome. The pathophysiology of sepsis-associated AKI (sepsis-AKI) remains incompletely understood, but mitochondria have emerged as key players in the pathogenesis. Therefore, our aim was to identify mitochondrial damage in patients with sepsis-AKI. METHODS: We conducted a clinical laboratory study using "warm" postmortem biopsies from sepsis-associated AKI patients from a university teaching hospital. Biopsies were taken from adult patients (n = 14) who died of sepsis with AKI at the intensive care unit (ICU) and control patients (n = 12) undergoing tumor nephrectomy. To define the mechanisms of the mitochondrial contribution to the pathogenesis of sepsis-AKI, we explored mRNA and DNA expression of mitochondrial quality mechanism pathways, DNA oxidation and mitochondrial DNA (mtDNA) integrity in renal biopsies from sepsis-AKI patients and control subjects. Next, we induced human umbilical vein endothelial cells (HUVECs) with lipopolysaccharide (LPS) for 48 h to mimic sepsis and validate our results in vitro. RESULTS: Compared to control subjects, sepsis-AKI patients had upregulated mRNA expression of oxidative damage markers, excess mitochondrial DNA damage and lower mitochondrial mass. Sepsis-AKI patients had lower mRNA expression of mitochondrial quality markers TFAM, PINK1 and PARKIN, but not of MFN2 and DRP1. Oxidative DNA damage was present in the cytosol of tubular epithelial cells in the kidney of sepsis-AKI patients, whereas it was almost absent in biopsies from control subjects. Oxidative DNA damage co-localized with both the nuclei and mitochondria. Accordingly, HUVECs induced with LPS for 48 h showed an increased mnSOD expression, a decreased TFAM expression and higher mtDNA damage levels. CONCLUSION: Sepsis-AKI induces mitochondrial DNA damage in the human kidney, without upregulation of mitochondrial quality control mechanisms, which likely resulted in a reduction in mitochondrial mass.

Left ventricular unloading with transaortic Impella 2.5 implantation in a pediatric patient supported by extracorporeal life support.

We report the case of a 12-year old female patient with Friedreich's ataxia and diabetes mellitus. Due to a progressive multiorgan failure, a veno-arterial extracorporeal membrane oxygenation was implanted through the axillary vessels. However, due to a lack of ejection and severe dilatation of the left ventricle, an Impella 2.5 was implanted. Due to the small diameter of the femoral arteries, we performed a trans-aortic implantation through a median sternotomy via a Dacron tube graft. We report on the procedure and perioperative outcome.

Potential of long non-coding RNA KCNQ1OT1 as a biomarker reflecting systemic inflammation, multiple organ dysfunction, and mortality risk in sepsis patients.

BACKGROUND: Long non-coding RNA potassium voltage-gated channel subfamily Q member 1 opposite strand 1 (lnc-KCNQ1OT1) represses inflammation and multiple organ dysfunction, whereas its clinical value in sepsis is unclear. Thus, this study aimed to explore this issue. METHODS: Lnc-KCNQ1OT1 from peripheral blood mononuclear cells were detected by RT-qPCR in 116 sepsis patients and 60 healthy controls (HCs). Moreover, sepsis patients were followed-up until death or up to 28 days. RESULTS: Lnc-KCNQ1OT1 decreased in patients with sepsis than in HCs (p < 0.001). In sepsis patients, lnc-KCNQ1OT1 was negatively correlated with sequential organ failure assessment (SOFA) scores (r = -0.344, p < 0.001) and several SOFA subscale scores (including respiratory system, coagulation, liver, and renal systems) (all r < 0, p < 0.05). Furthermore, lnc-KCNQ1OT1 was negatively correlated with CRP (r = -0.386, p < 0.001), TNF-α (r = -0.332, p < 0.001), IL-1ß (r = -0.319, p < 0.001), and IL-6 (r = -0.255, p = 0.006). Additionally, lnc-KCNQ1OT1 levels were lower in sepsis deaths than in sepsis survivors (p < 0.001), and the receiver operating characteristic curve showed that lnc-KCNQ1OT1 had an acceptable ability to predict 28-day mortality (area under the curve: 0.780, 95% confidence interval: 0.678-0.882). Meanwhile, its ability to predict 28-day mortality risk was higher than that of CRP, TNF-α, IL-1ß, and IL-6, but slightly lower than the SOFA score and acute physiology and chronic health evaluation II score. CONCLUSION: Lnc-KCNQ1OT1 serves as a potential biomarker for monitoring disease severity and prognosis in patients with sepsis.

A mutation in the Na-K-2Cl cotransporter-1 leads to changes in cellular metabolism.

The Na-K-Cl cotransporter-1 (NKCC1), by mediating the electroneutral transport of Na+ , K+ , and Cl- plays an important role in cell volume regulation, epithelial transport, and the control of neuronal excitability. Recently, we reported the first known human mutation in SLC12A2, the gene encoding NKCC1. The 17-year old patient suffers from multiorgan failure. Laboratory tests conducted on muscle and liver biopsies of the patient showed abnormal increase in mitochondrial DNA copy number and increased glycogen levels, indicating the possibility that the transporter may play a role in energy metabolism. Here, we show that fibroblasts isolated from the patient demonstrate a significant increase in mitochondrial respiration, compared to fibroblasts isolated from healthy individuals. Similarly, Madin Darby canine kidney (MDCK) cells transfected with enhanced green fluorescent protein (EGFP)-tagged mutant NKCC1 DNA demonstrated increased mitochondrial respiration when compared to MDCK cells expressing EGFP-tagged wild-type (WT) cotransporter. Direct inhibition of the cotransporter through addition of bumetanide did not change the rate of basal respiration, but led to increased maximal mitochondrial respiration. Fibroblasts extracted from NKCC1WT/DFX and NKCC1DFX/DFX mice also demonstrated a significant elevation in mitochondrial respiration, compared to fibroblasts isolated from their WT littermates. Expression of the mutant protein was associated with an increase in hydrogen peroxide and peroxidase activity and a decrease in messenger RNA transcript levels for protein involved in the unfolded protein response. These data reveal that cells expressing the mutant cotransporter demonstrate increased mitochondrial respiration and behave like they are experiencing a state of starvation.

Epigenetics of Sepsis.

OBJECTIVES: Recent evidence from the fields of microbiology and immunology, as well as a small number of human sepsis studies, suggest that epigenetic regulation may play a central role in the pathogenesis of sepsis. The term "epigenetics" refers to regulatory mechanisms that control gene expression but are not related to changes in DNA sequence. These include DNA methylation, histone modifications, and regulation of transcription via non-coding RNAs. Epigenetic modifications, occurring in response to external stressors, lead to changes in gene expression, and thus lie at the intersection between genetics and the environment. In this review, we examine data from in vitro studies, animal studies, and the existing human sepsis studies in epigenetics to demonstrate that epigenetic mechanisms are likely central to the pathogenesis of sepsis and that epigenetic therapies may have potential in the treatment of sepsis and its associated organ failures. DATA SOURCES: Online search of published scientific literature via Pubmed using the term "epigenetics" in combination with the terms "sepsis", "infection", "bacterial infection", "viral infection", "critical illness", "acute respiratory distress syndrome", and "acute lung injury". STUDY SELECTION: Articles were chosen for inclusion based on their relevance to sepsis, acute inflammation, sepsis-related immune suppression, and sepsis-related organ failure. Reference lists were reviewed to identify additional relevant articles. DATA EXTRACTION: Relevant data was extracted and synthesized for narrative review. DATA SYNTHESIS: Epigenetic regulation is a key determinant of gene expression in sepsis. At the onset of infection, host-pathogen interactions often result in epigenetic alterations to host cells that favor pathogen survival. In parallel, the host inflammatory response is characterized by epigenetic modifications in key regulatory genes, including tumor necrosis factor and interleukin-1ß. In human sepsis patients, multiple epigenetic modifying enzymes show differential expression in early sepsis, suggesting a role for epigenetics in coordinating the response to infection. In the later stages of sepsis, epigenetic modifications accompany endotoxin tolerance and the immune-suppressed state. In animal models, treatment with epigenetic modifiers can mitigate the effects of sepsis and improve survival as well as reverse sepsis-associated organ injury. CONCLUSIONS: Epigenetic modifications are associated with key phases of sepsis, from the host-pathogen interaction, to acute inflammation, to immune suppression. Epigenetic markers show promise in the diagnosis and prognosis of sepsis and epigenetic modifying agents show promise as therapeutic tools in animal models of sepsis. Human studies in the area of epigenetics are sorely lacking and should be a priority for sepsis researchers.

A novel ITPA variant causes epileptic encephalopathy with multiple-organ dysfunction.

Inborn errors of metabolism can cause epileptic encephalopathies. Biallelic loss-of-function variants in the ITPA gene, encoding inosine triphosphate pyrophosphatase (ITPase), have been reported in epileptic encephalopathies with lack of myelination of the posterior limb of the internal capsule, brainstem tracts, and tracts to the primary visual and motor cortices (MIM:616647). ITPase plays an important role in purine metabolism. In this study, we identified two novel homozygous ITPA variants, c.264-1 G > A and c.489-1 G > A, in two unrelated consanguineous families. The probands had epilepsy, microcephaly with characteristic magnetic resonance imaging findings (T2 hyperintensity signals in the pyramidal tracts of the internal capsule, delayed myelination, and thin corpus callosum), hypotonia, and developmental delay; both died in early infancy. Our report expands the knowledge of clinical consequences of biallelic ITPA variants.

Molecular regulation of plasma lipid levels during systemic inflammation and sepsis.

PURPOSE OF REVIEW: Sepsis is a common syndrome of multiorgan system dysfunction caused by a dysregulated inflammatory response to an infection and is associated with high rates of mortality. Plasma lipid and lipoprotein levels and composition change profoundly during sepsis and have emerged as both biomarkers and potential therapeutic targets for this condition. The purpose of this article is to review recent progress in the understanding of the molecular regulation of lipid metabolism during sepsis. RECENT FINDINGS: Patients who experience greater declines in high-density lipoprotein during sepsis are at much greater risk of succumbing to organ failure and death. Although the causality of these findings remains unclear, all lipoprotein classes can sequester and prevent the excessive inflammation caused by pathogen-associated lipids during severe infections such as sepsis. This primordial innate immune function has been best characterized for high-density lipoproteins. Most importantly, results from human genetics and preclinical animal studies have suggested that several lipid treatment strategies, initially designed for atherosclerosis, may hold promise as therapies for sepsis. SUMMARY: Lipid and lipoprotein metabolism undergoes significant changes during sepsis. An improved understanding of the molecular regulation of these changes may lead to new opportunities for the treatment of sepsis.