Lysosome and Cytoskeleton Pathways Are Robustly Enriched in the Blood of Septic Patients: A Meta-Analysis of Transcriptomic Data

Pathological and miRNA-mRNA Analyses Provide New Insights into the Immune Response of Clams to Vibrio Infection

Manila clam plays a crucial role in China's marine aquaculture industry. However, frequent vibriosis outbreaks severely hinder sustainable and healthy development of the shellfish aquaculture industry. This study indicated markedly decreased clam survival rates after 48 h of Vibrio alginolyticus challenge. Gill and hepatopancreas damage was investigated through histological observation. The activity of lysozyme in the gills and hepatopancreas peaked at 12 and 24 h, respectively. V. alginolyticus showed a maximum bacterial load in the gills and hepatopancreas at 12 and 24 h, respectively. Additionally, transcriptome sequencing of hepatopancreas revealed ten differentially expressed miRNAs in Va and Cn after 48 h infection with V. alginolyticus, corresponding to 100 target genes, with eight upregulated and two downregulated DE miRNAs. Gene ontology (GO) enrichment analysis identified 50 known miRNAs and 111 novel miRNAs, thereby predicting a total of 1840 target genes. KEGG analysis revealed significant changes in multiple signaling pathways, involving lysosomes, apoptosis, amino acid metabolism, and endocytosis, in response to V. alginolyticus stimulation. This study provided new information regarding the immune regulation mechanisms of R. philippinarum in response to V. alginolyticus stress.

Identification and validation of m6A RNA methylation and ferroptosis-related biomarkers in sepsis: transcriptome combined with single-cell RNA sequencing

Background

Sepsis, a systemic inflammatory response syndrome triggered by infection, is associated with high mortality rates and an increasing global incidence. While N 6-methyladenosine (m6A) RNA methylation and ferroptosis are implicated in inflammatory diseases, their specific genes and mechanisms in sepsis remain unclear.

Methods

Transcriptomic datasets of sepsis, along with m6A-related genes (m6A-RGs) and ferroptosis-related genes (FRGs), were sourced from public databases. Differentially expressed genes (DEGs) were identified between the sepsis and control groups, and m6A-RGs were analyzed through weighted gene co-expression network analysis (WGCNA) to uncover m6A module genes. These were then intersected with DEGs and FRGs to identify candidate genes. Biomarkers were identified using two machine learning methods, receiver operating characteristic (ROC) curves, and expression validation, followed by the development of a nomogram. Further in-depth analyses of the biomarkers were performed, including functional enrichment, immune infiltration, drug prediction, and molecular docking. Single-cell analysis was conducted to identify distinct cell clusters and evaluate biomarker expression at the single-cell level. Finally, reverse transcription-quantitative PCR (RT-qPCR) was employed to validate biomarker expression in clinical samples.

Results

DPP4 and TXN were identified as key biomarkers, showing higher expression in control and sepsis samples, respectively. The nomogram incorporating these biomarkers demonstrated strong diagnostic potential. Enrichment analysis highlighted their involvement in spliceosome function and antigen processing and presentation. Differential analysis of immune cell types revealed significant correlations between biomarkers and immune cells, such as macrophages and activated dendritic cells. Drug predictions identified gambogenic acid and valacyclovir as potential treatments, which were successfully docked with the biomarkers. Single-cell analysis revealed that the biomarkers were predominantly expressed in CD4+ memory cells, and CD16+ and CD14+ monocytes. The expression of DPP4 was further validated in clinical samples.

Conclusions

DPP4 and TXN were validated as biomarkers for sepsis, with insights into immune infiltration and therapeutic potential at the single-cell level, offering novel perspectives for sepsis treatment.

The lysosome-phagosome pathway mediates immune regulatory mechanisms in Mesocentrotus nudus against Vibrio coralliilyticus infection

Sea urchins are a popular model species for studying invertebrate diseases. The immune regulatory mechanisms of the sea urchin Mesocentrotus nudus during pathogenic infection are currently unknown. This study aimed to reveal the potential molecular mechanisms of M. nudus during resistance to Vibrio coralliilyticus infection by integrative transcriptomic and proteomic analyses. Here, we identified a total of 135,868 unigenes and 4,351 proteins in the four infection periods of 0 h, 20 h, 60 h and 100 h in M. nudus. In the I20, I60 and I100 infection comparison groups, 10,861, 15,201 and 8,809 differentially expressed genes (DEGs) and 2,188, 2,386 and 2,516 differentially expressed proteins (DEPs) were identified, respectively. We performed an integrated comparative analysis of the transcriptome and proteome throughout the infection phase and found very a low correlation between transcriptome and proteome changes. KEGG pathway analysis revealed that most upregulated DEGs and DEPs were involved in immune strategies. Notably, "lysosome" and "phagosome" activated throughout the infection process, could be considered the two most important enrichment pathways at the mRNA and protein levels. The significant increase in phagocytosis of infected M. nudus coelomocytes further demonstrated that the lysosome-phagosome pathway played an important immunological role in M. nudus resistance to pathogenic infection. Key gene expression profiles and protein‒protein interaction analysis revealed that cathepsin family and V-ATPase family genes might be key bridges in the lysosome-phagosome pathway. In addition, the expression patterns of key immune genes were verified using qRT‒PCR, and the different expression trends of candidate genes reflected, to some extent, the regulatory mechanism of immune homeostasis mediated by the lysosome-phagosome pathway in M. nudus against pathogenic infection. This work will provide new insights into the immune regulatory mechanisms of sea urchins under pathogenic stress and help identify key potential genes/proteins for sea urchin immune responses.

NO news: S-(de)nitrosylation of cathepsins and their relationship with cancer

Tumor formation and progression have been much of a study over the last two centuries. Recent studies have seen different developments for the early diagnosis and treatment of the disease; some of which even promise survival of the patient. Cysteine proteases, mainly cathepsins have been unequivocally identified as putative worthy players of redox imbalance that contribute to the premonition and further progression of cancer by interfering in the normal extracellular and intracellular proteolysis and initiating a proteolytic cascade. The present review article focuses on the study of cancer so far, while establishing facts on how future studies focused on the cellular interrelation between nitric oxide (NO) and cancer, can direct their focus on cathepsins. For a tumor cell to thrive and synergize a cancerous environment, different mutations in the proteolytic and signaling pathways and the proto-oncogenes, oncogenes, and the tumor suppressor genes are made possible through cellular biochemistry and some cancer-stimulating environmental factors. The accumulated findings show that S-nitrosylation of cathepsins under the influence of NO-donors can prevent the invasion of cancer and cause cancer cell death by blocking the activity of cathepsins as well as the major denitrosylase systems using a multi-way approach. Faced with a conundrum of how to fill the gap between the dodging of established cancer hallmarks with cathepsin activity and gaining appropriate research/clinical accreditation using our hypothesis, the scope of this review also explores the interplay and crosstalk between S-nitrosylation and S-(de)nitrosylation of this protease and highlights the utility of charging thioredoxin (Trx) reductase inhibitors, low-molecular-weight dithiols, and Trx mimetics using efficient drug delivery system to prevent the denitrosylation or regaining of cathepsin activity in vivo. In foresight, this raises the prospect that drugs or novel compounds that target cathepsins taking all these factors into consideration could be deployed as alternative or even better treatments for cancer, though further research is needed to ascertain the safety, efficiency and effectiveness of this approach.

Key Signature Genes of Early Terminal Granulocytic Differentiation Distinguish Sepsis From Systemic Inflammatory Response Syndrome on Intensive Care Unit Admission

Infection can induce granulopoiesis. This process potentially contributes to blood gene classifiers of sepsis in systemic inflammatory response syndrome (SIRS) patients. This study aimed to identify signature genes of blood granulocytes from patients with sepsis and SIRS on intensive care unit (ICU) admission. CD15+ cells encompassing all stages of terminal granulocytic differentiation were analyzed. CD15 transcriptomes from patients with sepsis and SIRS on ICU admission and presurgical controls (discovery cohort) were subjected to differential gene expression and pathway enrichment analyses. Differential gene expression was validated by bead array in independent sepsis and SIRS patients (validation cohort). Blood counts of granulocyte precursors were determined by flow cytometry in an extension of the validation cohort. Despite similar transcriptional CD15 responses in sepsis and SIRS, enrichment of canonical pathways known to decline at the metamyelocyte stage (mitochondrial, lysosome, cell cycle, and proteasome) was associated with sepsis but not SIRS. Twelve of 30 validated genes, from 100 selected for changes in response to sepsis rather than SIRS, were endo-lysosomal. Revisiting the discovery transcriptomes revealed an elevated expression of promyelocyte-restricted azurophilic granule genes in sepsis and myelocyte-restricted specific granule genes in sepsis followed by SIRS. Blood counts of promyelocytes and myelocytes were higher in sepsis than in SIRS. Sepsis-induced granulopoiesis and signature genes of early terminal granulocytic differentiation thus provide a rationale for classifiers of sepsis in patients with SIRS on ICU admission. Yet, the distinction of this process from noninfectious tissue injury-induced granulopoiesis remains to be investigated.

Bacterial lipoproteins in sepsis

Bacterial lipoproteins are membrane proteins derived from both gram-negative and gram-positive bacteria. They seem to have diverse functions not only on bacterial growth, but also play an important role in host's virulence. Bacterial lipoproteins exert their action on host immune cells via TLR2/1 or TLR2/6. Therefore, bacterial lipoproteins also need to be considered while addressing bacterial pathogenicity besides classical bacterial endotoxin like LPS and other microbial associated molecular patterns such as LTA, and peptidoglycans. In this mini-review, we provide an overview of general bacterial lipoprotein biosynthesis and the need to understand the lipoprotein-mediated pathogenicity in diseases like sepsis.

Identifying COVID-19-Specific Transcriptomic Biomarkers with Machine Learning Methods

COVID-19, a severe respiratory disease caused by a new type of coronavirus SARS-CoV-2, has been spreading all over the world. Patients infected with SARS-CoV-2 may have no pathogenic symptoms, i.e., presymptomatic patients and asymptomatic patients. Both patients could further spread the virus to other susceptible people, thereby making the control of COVID-19 difficult. The two major challenges for COVID-19 diagnosis at present are as follows: (1) patients could share similar symptoms with other respiratory infections, and (2) patients may not have any symptoms but could still spread the virus. Therefore, new biomarkers at different omics levels are required for the large-scale screening and diagnosis of COVID-19. Although some initial analyses could identify a group of candidate gene biomarkers for COVID-19, the previous work still could not identify biomarkers capable for clinical use in COVID-19, which requires disease-specific diagnosis compared with other multiple infectious diseases. As an extension of the previous study, optimized machine learning models were applied in the present study to identify some specific qualitative host biomarkers associated with COVID-19 infection on the basis of a publicly released transcriptomic dataset, which included healthy controls and patients with bacterial infection, influenza, COVID-19, and other kinds of coronavirus. This dataset was first analysed by Boruta, Max-Relevance and Min-Redundancy feature selection methods one by one, resulting in a feature list. This list was fed into the incremental feature selection method, incorporating one of the classification algorithms to extract essential biomarkers and build efficient classifiers and classification rules. The capacity of these findings to distinguish COVID-19 with other similar respiratory infectious diseases at the transcriptomic level was also validated, which may improve the efficacy and accuracy of COVID-19 diagnosis.

Reduning injection and its effective constituent luteoloside protect against sepsis partly via inhibition of HMGB1/TLR4/NF-κB/MAPKs signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Reduning injection (RDN), a popular traditional Chinese medicine, formulated by three herbs (i.e., Artemisia carvifolia Buch.-Ham. ex Roxb., Lonicera japonica Thunb., and Gardenia jasminoides J. Ellis), has been widely used to treat upper respiratory infectious diseases in China.

AIM OF THE STUDY

To investigate the protective effect of RDN on both lipopolysaccharides (LPS)- and cecal ligation and puncture (CLP)-induced septic mice. To identify the potentially effective constituent, and to determine its protective effect and underlying mechanism in vivo and in vitro.

MATERIALS AND METHODS

Male C57BL/6 mice were used to establish septic model by tail intravenous injection of 4 mg/kg LPS or CLP surgery. After modeling, mice were administered by tail intravenous injection of RDN in the dose of 16 or 8 mL/kg/day. The mortality, histopathology, plasma levels of inflammatory cytokines were evaluated respectively. In addition, we screened the potentially effective substances of RDN against sepsis by detecting the nitric oxide (NO) production in LPS-stimulated Raw 264.7 cells and verified the effect of luteoloside in CLP-induced septic mice subsequently. Finally, the underlying mechanisms of RDN and luteoloside were investigated in the inflammatory model in vitro.

RESULTS

Administration of RDN significantly reduced the mortality and increased the survival rate in both LPS- and CLP-induced septic mice. Meanwhile, RDN reduced the release of inflammatory cytokines accompanied by alleviating the organs damage of lung, liver, and kidney in CLP-induced septic mice. Moreover, several components from Gardenia jasminoides J. Ellis extract (ZZ) or Lonicera japonica Thunb and Artemisia carvifolia Buch.-Ham. ex Roxb extract (JQ) as well as the constituents of luteoloside, quercetin, and caffeic acid were screened out to have obvious anti-inflammatory activity, which may be the potentially effective substances of RDN against sepsis. We further verified the protective role of luteoloside in CLP-induced septic mice. In addition, RDN and luteoloside significantly inhibited both the secretion and translocation of mobility group box (HMGB)1, and HMGB1-mediated activation of TLR4/NF-κB/MAPKs signaling pathways.

CONCLUSION

RDN and its effective constituent luteoloside exhibited a significant protective effect against sepsis, which were potential candidate drugs for treatment of sepsis. The mechanism of antisepsis partly was related to inhibition of HMGB1/TLR4/NF-κB/MAPKs signaling pathways. The results provide an evidence base for the follow-up clinical application of RDN in treatment of sepsis.

Diagnostic potential of a gradient boosting-based model for detecting pediatric sepsis

Pediatric sepsis is a major cause of mortality of children worldwide. However, there is still a lack of easy-to-use predictive tools that can accurately diagnose sepsis in children. This study aimed to develop an optimal gene model for the diagnosis of pediatric sepsis using statistics and machine learning approaches. Combining gene expression profiles from a training cohort of 364 pediatric samples with a Least Absolute Shrinkage and Selection Operator analysis produced eighteen genes as diagnostic markers. With the implementation of a Gradient Boosting algorithm, a model designated PEDSEPS-GBM, that aggregated these markers was developed with optimal performance for the diagnosis of pediatric samples in the validation and two independent cohorts. Moreover, a web calculator with a user-friendly interface was established for PEDSEPS-GBM. This study presents a diagnostic model that holds great potential for the detection of pediatric sepsis, and demonstrates the biologic and clinical relevance of this model.

Discovery and Validation of Urinary Molecular Signature of Early Sepsis

Supplemental Digital Content is available in the text.

Objectives:

Identify alterations in gene expression unique to systemic and kidney-specific pathophysiologic processes using whole-genome analyses of RNA isolated from the urinary cells of sepsis patients.

Design:

Prospective cohort study.

Setting:

Quaternary care academic hospital.

Patients:

A total of 266 sepsis and 82 control patients enrolled between January 2015 and February 2018.

Interventions:

Whole-genome transcriptomic analysis of messenger RNA isolated from the urinary cells of sepsis patients within 12 hours of sepsis onset and from control subjects.

Measurements and Main Results:

The differentially expressed probes that map to known genes were subjected to feature selection using multiple machine learning techniques to find the best subset of probes that differentiates sepsis from control subjects. Using differential expression augmented with machine learning ensembles, we identified a set of 239 genes in urine, which show excellent effectiveness in classifying septic patients from those with chronic systemic disease in both internal and independent external validation cohorts. Functional analysis indexes disrupted biological pathways in early sepsis and reveal key molecular networks driving its pathogenesis.

Conclusions:

We identified unique urinary gene expression profile in early sepsis. Future studies need to confirm whether this approach can complement blood transcriptomic approaches for sepsis diagnosis and prognostication.

Gene expression profiling of sepsis-associated acute kidney injury

Sepsis accounts for more than 50% of all acute kidney injury (AKI) cases, and the combination of sepsis and AKI increases the risk of mortality from sepsis alone. However, to the best of our knowledge, the specific mechanism by which sepsis causes AKI has not yet been fully elucidated, and there is no targeted therapy for sepsis-associated AKI (SA-AKI). The present study investigated gene expression profiles using RNA sequencing (RNA-Seq) and bioinformatics analyses to assess the function of differentially expressed genes (DEGs) and the molecular mechanisms relevant to the prognosis of SA-AKI. From the bioinformatics analysis, 2,256 downregulated and 3,146 upregulated genes were identified (false discovery rate <0.1 and fold-change >2). Gene Ontology analysis revealed that the genes were enriched in cellular metabolic processes, cell death and apoptosis. The enriched transcription factors were v-rel reticuloendotheliosis viral oncogene homolog A and signaling transducer and activator of transcription 3. The enriched microRNAs (miRNAs or miRs) among the DEGs were miR-30e, miR-181a, miR-340, miR-466d and miR-466l. Furthermore, the enriched pathways included toll-like receptor signaling, nod-like receptor signaling and the Janus kinase/STAT signaling pathway. In conclusion, the present study identified certain prognosis-related genes, transcription factors, miRNAs and pathways by analyzing gene expression profiles of SA-AKI using RNA-Seq, which provides some basis for future experimental studies.

Global transcriptional regulation of STAT3- and MYC-mediated sepsis-induced ARDS

Background:

In recent years, sepsis-induced acute respiratory distress syndrome (ARDS) has remained a major clinical challenge for patients in intensive care units. While some progress has been reported over the years, the pathogenesis of ARDS still needs to be further expounded.

Methods:

In the present study, gene set enrichment analysis, differentially expressed genes analysis, short time-series expression miner, protein–protein interaction (PPI) networks, module analysis, hypergeometric test, and functional enrichment analysis were performed in whole blood gene expression profiles of sepsis and induced-sepsis ARDS to explore the molecular mechanism of sepsis-induced ARDS.

Results:

Further dysregulated genes in the process evolving from healthy control through sepsis to sepsis-induced ARDS were identified and organized into 10 functional modules based on their PPI networks. These functional modules were significantly involved in cell cycle, ubiquitin mediated proteolysis, spliceosome, and other pathways. MYC, STAT3, LEF1, and BRCA1 were potential transcription factors (TFs) regulating these modules. A TF-module-pathway global regulation network was constructed. In particular, our findings suggest that MYC and STAT3 may be the key regulatory genes in the underlying dysfunction of sepsis-induced ARDS. Receiver operating characteristic curve analysis showed the core genes in the global regulation network may be biomarkers for sepsis or sepsis-induced ARDS.

Conclusions:

We found that MYC and STAT3 may be the key regulatory genes in the underlying dysfunction of sepsis-induced ARDS.

The reviews of this paper are available via the supplementary material section.

New insights into pediatric community-acquired pneumonia gained from untargeted metabolomics: A preliminary study

BACKGROUND

Available diagnostics often fail to distinguish viral from bacterial causes of pediatric community-acquired pneumonia (pCAP). Metabolomics, which aims at characterizing diseases based on their metabolic signatures, has been applied to expand pathophysiological understanding of many diseases. In this exploratory study, we used the untargeted metabolomic analysis to shed new light on the etiology of pCAP.

METHODS

Liquid chromatography coupled with mass spectrometry was used to quantify the metabolite content of urine samples collected from children hospitalized for CAP of pneumococcal or viral etiology, ascertained using a conservative algorithm combining microbiological and biochemical data.

RESULTS

Fifty-nine children with CAP were enrolled over 16 months. Pneumococcal and viral cases were distinguished by means of a multivariate model based on 93 metabolites, 20 of which were identified and considered as putative biomarkers. Among these, six metabolites belonged to the adrenal steroid synthesis and degradation pathway.

CONCLUSIONS

This preliminary study suggests that viral and pneumococcal pneumonia differently affect the systemic metabolome, with a stronger disruption of the adrenal steroid pathway in pneumococcal pneumonia. This finding may lead to the discovery of novel diagnostic biomarkers and bring us closer to personalized therapy for pCAP.

Bioinformatics Analysis of Gene Expression Profiles for Risk Prediction in Patients with Septic Shock

Background

Septic shock occurs when sepsis is associated with critically low blood pressure, and has a high mortality rate. This study aimed to undertake a bioinformatics analysis of gene expression profiles for risk prediction in septic shock.

Material/Methods

Two good quality datasets associated with septic shock were downloaded from the Gene Expression Omnibus (GEO) database, GSE64457 and GSE57065. Patients with septic shock had both sepsis and hypotension, and a normal control group was included. The differentially expressed genes (DEGs) were identified using OmicShare tools based on R. Functional enrichment of DEGs was analyzed using DAVID. The protein-protein interaction (PPI) network was established using STRING. Survival curves of key genes were constructed using GraphPad Prism version 7.0. Each putative central gene was analyzed by receiver operating characteristic (ROC) curves using MedCalc statistical software.

Results

GSE64457 and GSE57065 included 130 RNA samples derived from whole blood from 97 patients with septic shock and 33 healthy volunteers to obtain 975 DEGs, 455 of which were significantly down-regulated and 520 were significantly upregulated (P<0.05). Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis identified significantly enriched DEGs in four signaling pathways, MAPK, TNF, HIF-1, and insulin. Six genes, WDR82, ASH1L, NCOA1, TPR, SF1, and CREBBP in the center of the PPI network were associated with septic shock, according to survival curve and ROC analysis.

Conclusions

Bioinformatics analysis of gene expression profiles identified four signaling pathways and six genes, potentially representing molecular mechanisms for the occurrence, progression, and risk prediction in septic shock.

Co-expression of HIF-1α, MDR1 and LAPTM4B in peripheral blood of solid tumors

The hypoxic tumor microenvironment is the major contributor of chemotherapy resistance in solid tumors. One of the key regulators of hypoxic responses within the cell is the hypoxia inducible factor-1α (HIF-1α) that is involved in transcription of genes promoting cell survival and chemotherapy resistance. Multidrug resistance gene-1 (MDR1) and Lysosome-associated protein transmembrane 4B-35 (LAPTM4B-35) are among those notable players which augment their responses to cellular hypoxia. MDR1 is the hypoxia responsive gene involved in multidrug resistance phenotype while LAPTM4B-35 is involved in chemotherapy resistance by stabilizing HIF-1α and overexpressing MDR1. Overexpression of HIF-1α, MDR1 and LAPTM4B has been associated with poor disease outcome in many cancers when studied individually at tissue level. However, accessibility of the tissues following the course of chemotherapy for ascertaining chemotherapy resistance is difficult and sometimes not clinically feasible. Therefore, indication of hypoxic biomarkers in patient’s blood can significantly alter the clinical outcome. Hence there is a need to identify a blood based marker to understand the disease progression. In the current study the expression of hypoxia associated chemotherapy resistance genes were studied in the peripheral blood lymphocytes of solid tumor patients and any potential correlation with disease progression were explored. The expression of HIF-1α, MDR1 and LAPTM4B was studied in blood of 72 breast, 42 ovarian, 32 colon and 21 prostate cancer patients through real time PCR analysis using delta cycle threshold method. The statistical scrutiny was executed through Fisher’s Exact test and the Spearman correlation method. There was 12–13 fold increased in expression of HIF-1α, two fold increased in MDR1 and 13–14 fold increased in LAPTM4B mRNA level in peripheral blood of breast, ovarian, prostate and colon cancer patients. In the current study there was an association of HIF-1α, MDR1 and LAPTM4B expression with advanced tumor stage, metastasis and chemotherapy treated group in breast, ovarian, prostate and colon cancer patients. The Spearman analysis also revealed a positive linear association among HIF-1α, MDR1 and LAPTM4B in all the studied cancer patients. The elevated expression of HIF-1α, MDR1 and LAPTM4B in peripheral blood of solid tumor patients can be a predictor of metastasis, disease progression and treatment response in these cancers. However, larger studies are needed to further strengthen their role as a potential biomarker for cancer prognosis.

Altered expression of TIAM1 in endotoxin-challenged airway epithelial cells and rodent septic models

BACKGROUND

In sepsis, reorganization of the actin cytoskeleton in the epithelium during inflammation will lead to a breakdown of epithelial barrier integrity, and contribute to the pathogenesis of sepsis, but the exact changes of various components regulating the actin cytoskeleton pathway remain unclear.

METHODS

We used lipopolysaccharide (LPS) challenged primary epithelial cells cultured at the air-liquid interface (ALI) to mimic epithelial barrier dysfunction during sepsis. Then we detected differential expression of T-lymphoma invasion and metastasis 1 (TIAM1) gene in lung epithelial cells and septic models.

RESULTS

LPS induced barrier dysfunction in human tracheobronchial epithelial cells (HTBEs) as measured by statistically significant changes in ionic and macromolecular permeability. We observed differential expression of TIAM1 gene. The protein expression of TIAM1 was decreased after LPS challenge, in human bronchial epithelial cells. Furthermore, the expression levels of both TIAM1 mRNA and protein were decreased in lungs of septic rodent models.

CONCLUSIONS

Given that expression levels of TIAM1 have been associated with mortality among sepsis patients, our findings have the potential for the development of diagnostic and treatment strategies relevant for patient management.

High-Density Lipoprotein, Mean Platelet Volume, and Uric Acid as Biomarkers for Outcomes in Patients With Sepsis: An Observational Study

BACKGROUND

We conducted an observational study evaluating the association between uric acid, mean platelet volume (MPV), and high-density lipoprotein (HDL) with complications and outcomes of patients with sepsis in a critical care setting.

METHODS

We followed patients with a diagnosis of severe sepsis and septic shock for a maximum of 28 days. Main outcomes assessed included length of stay (LOS), the need for renal replacement therapy (RRT), assisted mechanical ventilation (AMV), and vasopressor support as well as in-unit mortality.

RESULTS

The overall average age of the 37 patients enrolled was 48.1 (19.8) years; among them, 37.8% were male. Abdominal related (43.2%) and pulmonary (29.7%) were the main sites of infection. The overall Acute Physiology and Chronic Health Evaluation 2 (APACHE-2) median score was 19 (9-24). Acute kidney injury (AKI) was observed in 46.9% of the sample. In all, 54.1% required vasopressor support, 54.1% AMV, and 35.1% RRT. Patients with bacteremia were significantly more likely to require vasopressor support and those with urinary tract infections were significantly younger. We found increasing ΔMPV levels, higher APACHE-2 scores, lower HDL values, and a reduced age to be associated with a longer LOS. Higher scores on the APACHE-2 scale and lower levels of HDL significantly associated with higher odds for developing AKI. The need for vasopressor support was significantly associated with higher values of 72-hour MPV and with higher levels of baseline uric acid and lower values of initial HCO₃. Initial and 72-hour levels of MPV and higher scores in the APACHE-2 were all significantly correlated with the need for AMV. An increased probability of dying during follow-up was significantly correlated with increasing age.

CONCLUSION

We were able to establish significant associations between our candidate biomarkers and relevant outcomes for patients with sepsis. Our results support the use of these low-cost biomarkers in the assessment of prognosis of patients with sepsis.

Proteomic study revealed cellular assembly and lipid metabolism dysregulation in sepsis secondary to community-acquired pneumonia

Sepsis is a life-threatening disorder characterized by organ dysfunction and a major cause of mortality worldwide. The major challenge in studying sepsis is its diversity in such factors as age, source of infection and etiology. Recently, genomic and proteomic approaches have improved our understanding of its complex pathogenesis. In the present study, we use quantitative proteomics to evaluate the host proteome response in septic patients secondary to community-acquired pneumonia (CAP). Samples obtained at admission and after 7 days of follow-up were analyzed according to the outcomes of septic patients. The patients' proteome profiles were compared with age- and gender-matched healthy volunteers. Bioinformatic analyses of differentially expressed proteins showed alteration in the cytoskeleton, cellular assembly, movement, lipid metabolism and immune responses in septic patients. Actin and gelsolin changes were assessed in mononuclear cells using immunofluorescence, and a higher expression of gelsolin and depletion of actin were observed in survivor patients. Regarding lipid metabolism, changes in cholesterol, HDL and apolipoproteins were confirmed using enzymatic colorimetric methods in plasma. Transcriptomic studies revealed a massive change in gene expression in sepsis. Our proteomic results stressed important changes in cellular structure and metabolism, which are possible targets for future interventions of sepsis.

Emerging roles for TFEB in the immune response and inflammation

Inflammation is a central feature of an effective immune response, which functions to eliminate pathogens and other foreign material, and promote recovery; however, dysregulation of the inflammatory response is associated with a wide variety of disease states. The autophagy-lysosome pathway is one of 2 major degradative pathways used by the cell and serves to eliminate long-lived and dysfunctional proteins and organelles to maintain homeostasis. Mounting evidence implicates the autophagy-lysosome pathway as a key player in regulating the inflammatory response; hence many inflammatory diseases may fundamentally be diseases of autophagy-lysosome pathway dysfunction. The recent identification of TFEB and TFE3 as master regulators of macroautophagy/autophagy and lysosome function raises the possibility that these transcription factors may be of central importance in linking autophagy and lysosome dysfunction with inflammatory disorders. Here, we review the current state of knowledge linking TFEB and TFE3 to the processes of autophagy and inflammation and highlight several conditions, which are linked by these factors.

Sepsis leads to thyroid impairment and dysfunction in rat model

Sepsis was a systemic response to a local infection. Apoptosis was observed in the experimental sepsis. In this study, cecal ligation and puncture (CLP)-induced sepsis was established in rats. We found that sepsis decreased thyroid hormone levels, including triiodothyronine (T3), thyroxine (T4), free T3 (fT3), and free T4 (fT4). Besides, we detected the increasing expression level of Caspase-3 and increasing ratio of TUNEL positive cells in the thyroid after sepsis. Furthermore, a series of pathological ultrastructural changes were observed in thyroid follicular epithelial cells by CLP-induced sepsis. This study established a sepsis animal model and provided the cellular and molecular basis for decoding the pathological mechanism in thyroid with the occurrence of sepsis.

Sepsis: in search of cure

INTRODUCTION

Sepsis is a complex inflammatory disorder believed to originate from an infection by any types of microbes and/or their products. It is the leading cause of death in intensive care units (ICUs) throughout the globe. The mortality rates depend both on the severity of infection and the host's response to infection.

METHODS

Literature survey on pathobiology of sepsis in general and failure of more than hundred clinical trials conducted so far in search of a possible cure for sepsis resulted in the preparation of this manuscript.

FINDINGS

Sepsis lacks a suitable animal model that mimics human sepsis. However, based on the results obtained in animal models of sepsis, clinical trials conducted so far have been disappointing. Although involvement of multiple mediators and pathways in sepsis has been recognized, only few components are being targeted and this could be the major reason behind the failure of clinical trials.

CONCLUSION

Inability to recognize a single critical mediator of sepsis may be the underlying cause for the poor therapeutic intervention of sepsis. Therefore, sepsis is still considered as a disease-in search of cure.

MFHAS1 Is Associated with Sepsis and Stimulates TLR2/NF-κB Signaling Pathway Following Negative Regulation

Malignant fibrous histiocytoma amplified sequence 1 (MFHAS1) has a potential immunoregulatory role dependent on Toll-like receptors (TLRs). TLR2, associated with deleterious systemic inflammation, cardiac dysfunction, and acute kidney injury, acts synergistically in sepsis. The role of MFHAS1 in targeting TLR2 involved in sepsis has not been examined thus far. This study aimed to examine the relationship of MFHAS1 and sepsis, and the effect of MFHAS1 on the TLR2 signaling pathway. Blood samples were collected from eight sepsis patients after surgery and eight patients undergoing selective surgery to determine blood MFHAS1 levels. HEK 293 cells, RAW 264.7 macrophages and THP-1 monocytes were used to confirm the effect of MFHAS1 on TLR2 signaling pathway. Our study showed that blood MFHAS1 was significantly elevated in septic patients, and MFHAS1 was more increased in mononuclear cells from septic patients. Pam3CSK4 (TLR2 ligand) was found to induce MFHAS1 production in RAW 264.7 murine macrophages and THP-1 human monocytes in a time-dependent manner. MFHAS1 has dual effects on TLR2 signaling pathway and inflammation, i.e., inhibitory effect at 6 hours, and then stimulatory effect after 24 hours through the activation of TLR2/NF-κB signaling pathway, and MFHAS1 induced the phosphorylation of JNK and p38 after TLR2 stimulation.