Proteome analysis of hemofilter adsorbates to identify novel substances of sepsis: a pilot study

Study on the activity and mechanism of herbal formula anti-infection powder (AIP) against influenza-virus-induced pneumonia through genetic susceptibility genes

ETHNOPHARMACOLOGICAL RELEVANCE

Anti-infection powder (AIP), a patented Chinese herbal formulation, is used traditionally in the treatment of upper respiratory tract infections. In this study, an ethanol extract of AIP was demonstrated to inhibit influenza A virus (IAV) infection and IAV-induced pneumonia (IVP), both in vitro and in vivo, highlighting its potential mechanism of action.

AIM OF THE STUDY

To determine the anti-IAV activity of AIP and to explore the possible mechanisms of inhibiting IAV-induced pneumonia.

MATERIALS AND METHODS

An ethanol extract was extracted from AIP and its major ingredients were determined by high-performance liquid chromatography (HPLC). An IAV-infected A549 cell model and an IAV-induced mouse pneumonia model were established to evaluate the therapeutic effects of AIP on IVP in vivo and in vitro. The mice were respectively administered AIP at high- and low-dose in different groups. The anti-IAV activity of AIP was evaluated by detecting viral load, lung lesion, lung index, suvival time, inflammatory cytokines and transcriptomic analysis in the lung tissue. The potential pathways and targets that involved in AIP against IVP were predicted by network pharmacology. Mendelian randomization (MR), colocalization analysis, and molecular docking were employed to identify novel therapeutic targets for IVP. Polymerase chain reaction (PCR) and Western blot (WB) techniques were used to confirm the effect of AIP on the expression of risk target genes in the lungs of IVP mice.

RESULTS

In A549 cell line, AIP effectively inhibited IAV infection with IC50 values of 65.49 μg/mL. The anti-IAV activity of AIP was mainly determined by chlorogenic acid, forsythiarin, puerarin, paeoniflorin and prim-o-glucosylcimigin. Moreover, AIP inhibited the neuraminidase activity and the M gene expression in vitro. In vivo, oral administration of AIP significantly reduced viral load and improved lung tissue lesions. AIP decreased the concentration of pro-inflammatory factors such as IL-1β, TNF-α, and IFN-γ, and significantly increased the concentration of the anti-inflammatory factor IL-4. According to network pharmacology analysis, toll-like receptor signaling pathway, chemokine signaling pathway, and TNF signaling pathway may be the possible mechanisms by which AIP inhibits IVP and regulates excessive inflammatory response.Two new genes, LRG1 and PSMA4, associated with genetic susceptibility to influenza and pneumonia, predicted as potential IVP drug target genes by MR and colocalization analysis. The antiviral mechanism of AIP may be to inhibit the expression levels of LRG1 and PSMA4 in lungs of mouse IVP.

CONCLUSIONS

AIP exhibited anti-IAV activities both in vitro and in vivo. AIP had a protective effect against pneumonia caused by influenza virus and can inhibit the progression of inflammation. This effect may be associated with its ability to inhibit the expression levels of genetic susceptibility genes (LRG1 and PSMA4) in lungs of mouse IVP. The findings of this study enhance our understanding of the role and mechanisms of AIP in the treatment of IVP.

LRG1 Contributes to the Pathogenesis of Multiple Kidney Diseases: A Comprehensive Review

Background

The increasing prevalence of kidney diseases has become a significant public health issue, with a global prevalence exceeding 10%. In order to accurately identify biochemical changes and treatment outcomes associated with kidney diseases, novel methods targeting specific genes have been discovered. Among these genes, leucine-rich α-2 glycoprotein 1 (LRG1) has been identified to function as a multifunctional pathogenic signaling molecule in multiple diseases, including kidney diseases. This study aims to provide a comprehensive overview of the current evidence regarding the roles of LRG1 in different types of kidney diseases.

Summary

Based on a comprehensive review, it was found that LRG1 was upregulated in the urine, serum, or renal tissues of patients or experimental animal models with multiple kidney diseases, such as diabetic nephropathy, kidney injury, IgA nephropathy, chronic kidney diseases, clear cell renal cell carcinoma, end-stage renal disease, canine leishmaniosis-induced kidney disease, kidney fibrosis, and aristolochic acid nephropathy. Mechanistically, the role of LRG1 in kidney diseases is believed to be detrimental, potentially through its regulation of various genes and signaling cascades, i.e., fibronectin 1, GPR56, vascular endothelial growth factor (VEGF), VEGFR-2, death receptor 5, GDF15, HIF-1α, SPP1, activin receptor-like kinase 1-Smad1/5/8, NLRP3-IL-1b, and transforming growth factor β pathway.

Key Messages

Further research is needed to fully comprehend the molecular mechanisms by which LRG1 contributes to the pathogenesis and pathophysiology of kidney diseases. It is anticipated that targeted treatments focusing on LRG1 will be utilized in clinical trials and implemented in clinical practice in the future.

Combination of HBA1, TTR, and SERPINF2 in plasma defines phenotype correlated with severe burn outcome

Recent advancements in proteomics allow for the concurrent identification and quantification of multiple proteins. This study aimed to identify proteins associated with severe burn pathology and establish a clinically useful molecular pathology classification. In a retrospective observational study, blood samples were collected from severe burn patients. Proteins were measured using mass spectrometry, and prognosis-related proteins were extracted by comparing survivors and non-survivors. Enrichment and ROC analyses evaluated the extracted proteins, followed by latent class analysis. Measurements were performed on 83 burn patients. In the non-survivor group, ten proteins significantly changing on the day of injury were associated with metabolic processes and toxin responses. ROC analysis identified HBA1, TTR, and SERPINF2 with AUCs > 0.8 as predictors of 28-day mortality. Latent class analysis classified three molecular pathotypes, and plasma mass spectrometry revealed ten proteins associated with severe burn prognosis. Molecular pathotypes based on HBA1, TTR, and SERPINF2 significantly correlated with outcomes.

The novel biomarkers for assessing clinical benefits of continuous renal replacement therapy in pediatric sepsis: a pilot study

BACKGROUND

Continuous renal replacement therapy (CRRT) has been considered as an adjuvant therapy for sepsis. However, the novel biomarker to evaluate the benefits of CRRT is limited. The aim of this study was to explore the novel biomarkers involved in the impact of CRRT in pediatric sepsis.

METHODS

The serum proteomic profiles on the 7th day after CRRT (CRRT 7th day) compared with before CRRT (CRRT 1st day) was determined in 3 children with sepsis as a discovery set. The screened candidates were confirmed in the validation cohort including patients received CRRT (CRRT group) and without CRRT (non-CRRT group). We defined that pediatric sequential organ failure assessment score (pSOFA) in pediatric patients with sepsis decreased by 2 points or more on the CRRT 1st day compared with CRRT initiation as CRRT responders. The changes of serum biomarkers were compared between CRRT responders and CRRT non-responders. Moreover, correlation analysis was further conducted in pediatric sepsis.

RESULTS

A total of 145 differentially expressed proteins were found according to the serum proteomics profiles. By visualizing the interaction between the differential proteins, 6 candidates (Lysozyme C [LYZ], Leucine-rich alpha-2-glycoprotein [LRG1], Fibromodulin [FMOD], Alpha-1-antichymotrypsin [SERPINA3], L-selectin [SELL], Monocyte differentiation antigen CD14 [CD14]) were screened. In the validation cohort, serum levels of LYZ and LRG1 showed a higher trend on the CRRT 7th day than that on the 1st day in the non-CRRT group. However, the changes in levels of LYZ and LRG1 on the 7th day was significant in the CRRT group (p = 0.016, p = 0.009, respectively). Moreover, the levels of LYZ and LRG1 on the CRRT 7th day in the CRRT group were significantly higher than that in the non-CRRT group (p < 0.001, p = 0.025). Decreased levels of CD14 were associated with sepsis recovery, but not associated with CRRT. There were no significantly difference in serum FMOD, SERPINA3, and SELL levels. Importantly, serum LYZ and LRG1 levels changed in CRRT responders, but not CRRT non-responders. Further analysis indicated that serum LYZ levels were correlated to total platelet counts, aspartate aminotransferase (ALT), alanine aminotransferase (AST), and albumin levels, and serum LRG1 level were correlated to total platelet count and TBIL levels on the 1st day in the CRRT group. Protein-protein interaction network analysis displayed that serum LYZ and LRG1 were involved in the process of inflammatory response, leucocytes adhesion to vascular endothelial cell, as well as complement activation.

CONCLUSION

Elevated serum LYZ and LRG1 levels are associated with clinical benefits of CRRT during sepsis.

Multi-Omics Techniques Make it Possible to Analyze Sepsis-Associated Acute Kidney Injury Comprehensively

Sepsis-associated acute kidney injury (SA-AKI) is a common complication in critically ill patients with high morbidity and mortality. SA-AKI varies considerably in disease presentation, progression, and response to treatment, highlighting the heterogeneity of the underlying biological mechanisms. In this review, we briefly describe the pathophysiology of SA-AKI, biomarkers, reference databases, and available omics techniques. Advances in omics technology allow for comprehensive analysis of SA-AKI, and the integration of multiple omics provides an opportunity to understand the information flow behind the disease. These approaches will drive a shift in current paradigms for the prevention, diagnosis, and staging and provide the renal community with significant advances in precision medicine in SA-AKI analysis.

Time Series Transcriptomic Analysis by RNA Sequencing Reveals a Key Role of PI3K in Sepsis-Induced Myocardial Injury in Mice

Septic cardiomyopathy is the main complication and cause of death of severe sepsis with limited therapeutic strategy. However, the molecular mechanism of sepsis-induced cardiac injury remains unclear. The present study was designed to investigate differentially expressed genes (DEGs) involved in the pathogenesis of septic cardiomyopathy induced by cecal ligation and puncture (CLP) in mice. Male C57BL/6J mice (8-10 weeks old) were subjected to CLP with 21-gauge needles for 24, 48, and 72 h. Myocardial function was assessed by echocardiography. The pathological changes of the heart were evaluated by hematoxylin and eosin as well as immunohistochemical staining. Time series RNA sequencing was utilized to investigate the gene expression profiles. CLP surgery resulted in a significant decrease of animal survival rate and left ventricle contractile function, and an increase in cardiac dilation and infiltration of proinflammatory cells including Mac-2⁺ macrophages in a time-dependent manner. RNA sequencing identified 5,607 DEGs in septic myocardium at 24, 48, and 72 h after CLP operation. Moreover, gene ontology analysis revealed that these DEGs were mainly associated with the biological processes, including cell adhesion, immune system process, inflammatory response, and positive regulation of cell migration. KEGG pathway enrichment analysis indicated that Staphylococcus aureus infection, osteoclast differentiation, leishmaniasis, and ECM-receptor interaction were significantly altered in septic hearts. Notably, Pik3r1 and Pik3r5 were localized in the center of the gene co-expression network, and were markedly upregulated in CLP-induced septic myocardium. Further, blocking PI3Kγ by the specific inhibitor CZC24832 significantly protected against sepsis-induced cardiac impairment. The present study uncovers the gene expression signatures of CLP-induced myocardial injury and sheds light on the role of Pik3r5 in septic cardiomyopathy.

A Three-Protein Panel to Support the Diagnosis of Sepsis in Children

Sepsis is a syndrome without a standard validated diagnostic test. Early recognition is crucial. Serum proteome analysis in children with sepsis may identify new biomarkers. This study aimed to find suitable blood biomarkers for an early diagnosis of sepsis. An analytical observational case-control study was carried out in a single center. Children admitted to a Pediatric Intensive Care Unit with clinical diagnosed sepsis were eligible for study. A proteomic analysis conducted by mass spectrometry was performed. Forty patients with sepsis and 24 healthy donors were recruited. Proteomics results revealed 44 proteins differentially expressed between patients and healthy controls. Six proteins were selected to be validated: lactoferrin, serum amyloid-A1 (SAA-1), complement factor B, leucine-rich alpha-2 glycoprotein (LRG1), soluble interleukin-2 alpha chain receptor (sCD25) and soluble haptoglobin−hemoglobin receptor. Our results showed that sCD25, SAA-1, and LRG1 had high levels of specificity and sensitivity, as well as an excellent area under the ROC curve (>0.9). Our study provides a serum proteomic analysis that identifies new diagnostic biomarkers in sepsis. SAA-1, sCD25 and LRG1 were able to separate septic from healthy donor, so they could be used together with other clinical and analytical features to improve sepsis diagnosis in children.

Leucine rich alpha-2-glycoprotein 1 (Lrg1) silencing protects against sepsis-mediated brain injury by inhibiting transforming growth factor beta1 (TGFβ1)/SMAD signaling pathway

Sepsis-associated encephalopathy (SAE) is key manifestation of sepsis which is responsible for increased morbidity and mortality. Leucine rich alpha-2-glycoprotein 1 (Lrg1) is a secreted protein implicated in a variety of diseases. We aimed to explore the effects and potential mechanism of Lrg1 on sepsis-mediated brain injury. A sepsis-induced brain damage mice model was established. Then, ELISA was utilized to detect the levels of inflammatory factors in brain tissues. Behavioral performance, spatial learning and memory of mice were evaluated by open field test and Morris water maze test. The number of neurons was tested by H&E staining. Lrg1 expression was evaluated by RT-qPCR and western blot. In vitro, mouse hippocampal neuronal cell line (HT22) was stimulated by lipopolysaccharide (LPS). After Lrg1 silencing, cell viability was determined using CCK-8 and cell apoptosis was assessed by TUNEL. The levels of inflammatory factors were detected by ELISA. Moreover, western blot was applied to analyze the expression of proteins in transforming growth factor beta1 (TGFβ1)/SMAD signaling. Results revealed that mice in the model group showed obvious behavioral changes. Lrg1 was highly expressed in the brain tissues of model mice. Besides, Lrg1 knockdown suppressed the inflammation and apoptosis of LPS-induced HT22 cells. Moreover, Lrg1 silencing caused the inactivation of TGFβ1/SMAD signaling. Rescue assays confirmed that TGFβ1 overexpression reversed the impacts of Lrg1 deletion on the inflammation and apoptosis in LPS-induced HT22 cells. Collectively, Lrg1 silencing alleviates brain injury in SAE via inhibiting TGFβ1/SMAD signaling, implying that Lrg1 might serve as a promising target for SAE treatment.

Research Progress on Leucine-Rich Alpha-2 Glycoprotein 1: A Review

Leucine-rich alpha⁃2 glycoprotein 1 (LRG1) is an important member of the leucine-rich repetitive sequence protein family. LRG1 was mainly involved in normal physiological activities of the nervous system, such as synapse formation, synapse growth, the development of nerve processes, neurotransmitter transfer and release, and cell adhesion molecules or ligand-binding proteins. Also, LRG1 affected the development of respiratory diseases, hematological diseases, endocrine diseases, tumor diseases, eye diseases, cardiovascular diseases, rheumatic immune diseases, infectious diseases, etc. LRG1 was a newly discovered important upstream signaling molecule of transforming growth factor⁃β (TGF⁃β) that affected various pathological processes through the TGF⁃β signaling pathway. However, research on LRG1 and its involvement in the occurrence and development of diseases was still in its infancy and the current studies were mainly focused on proteomic detection and basic animal experimental reports. We could reasonably predict that LRG1 might act as a new direction and strategy for the treatment of many diseases.

LRG1: an emerging player in disease pathogenesis

The secreted glycoprotein leucine-rich α-2 glycoprotein 1 (LRG1) was first described as a key player in pathogenic ocular neovascularization almost a decade ago. Since then, an increasing number of publications have reported the involvement of LRG1 in multiple human conditions including cancer, diabetes, cardiovascular disease, neurological disease, and inflammatory disorders. The purpose of this review is to provide, for the first time, a comprehensive overview of the LRG1 literature considering its role in health and disease. Although LRG1 is constitutively expressed by hepatocytes and neutrophils, Lrg1-/- mice show no overt phenotypic abnormality suggesting that LRG1 is essentially redundant in development and homeostasis. However, emerging data are challenging this view by suggesting a novel role for LRG1 in innate immunity and preservation of tissue integrity. While our understanding of beneficial LRG1 functions in physiology remains limited, a consistent body of evidence shows that, in response to various inflammatory stimuli, LRG1 expression is induced and directly contributes to disease pathogenesis. Its potential role as a biomarker for the diagnosis, prognosis and monitoring of multiple conditions is widely discussed while dissecting the mechanisms underlying LRG1 pathogenic functions. Emphasis is given to the role that LRG1 plays as a vasculopathic factor where it disrupts the cellular interactions normally required for the formation and maintenance of mature vessels, thereby indirectly contributing to the establishment of a highly hypoxic and immunosuppressive microenvironment. In addition, LRG1 has also been reported to affect other cell types (including epithelial, immune, mesenchymal and cancer cells) mostly by modulating the TGFβ signalling pathway in a context-dependent manner. Crucially, animal studies have shown that LRG1 inhibition, through gene deletion or a function-blocking antibody, is sufficient to attenuate disease progression. In view of this, and taking into consideration its role as an upstream modifier of TGFβ signalling, LRG1 is suggested as a potentially important therapeutic target. While further investigations are needed to fill gaps in our current understanding of LRG1 function, the studies reviewed here confirm LRG1 as a pleiotropic and pathogenic signalling molecule providing a strong rationale for its use in the clinic as a biomarker and therapeutic target.

The application of omic technologies to research in sepsis-associated acute kidney injury

Acute kidney injury (AKI) is common in critically ill children and adults, and sepsis-associated AKI (SA-AKI) is the most frequent cause of AKI in the ICU. To date, no mechanistically targeted therapeutic interventions have been identified. High-throughput "omic" technologies (e.g., genomics, proteomics, metabolomics, etc.) offer a new angle of approach to achieve this end. In this review, we provide an update on the current understanding of SA-AKI pathophysiology. Omic technologies themselves are briefly discussed to facilitate interpretation of studies using them. We next summarize the body of SA-AKI research to date that has employed omic technologies. Importantly, omic studies are helping to elucidate a pathophysiology of SA-AKI centered around cellular stress responses, metabolic changes, and dysregulation of energy production that underlie its clinical features. Finally, we propose opportunities for future research using clinically relevant animal models, integrating multiple omic technologies and ultimately progressing to translational human studies focusing therapeutic strategies on targeted disease mechanisms.

Leucine-rich α2-glycoprotein-1 upregulation in plasma and kidney of patients with lupus nephritis

BACKGROUND

Increased leucine-rich α2-glycoprotein-1 (LRG1) has been observed in various inflammatory and autoimmune diseases. We aimed to explore the expression and role of LRG1 in lupus nephritis (LN).

METHODS

Plasma LRG1 (pLRG1) was measured by enzyme-linked immunosorbent assay in 101 patients with renal biopsy-proven LN and 21 healthy controls (HC). Relationships between pLRG1 and clinical and pathological characteristics were analyzed. The expression of LRG1 in peripheral blood leukocytes and kidney was detected by flow cytometry, immunohistochemistry and immunofluorescence, respectively. Further cell experiments were focused on the role of LRG1.

RESULTS

We found that LRG1 was expressed in plasma, some peripheral blood leukocytes, proximal tubule and several inflammatory cells. The levels of LRG1 in plasma, peripheral blood leukocytes and kidney were elevated in LN patients as compared to HC. Plasma expression levels of LRG1 correlated positively with renal function and renal disease activity, and reflect specific pathologic lesions in the kidneys of patients with LN. Interleukin-1β and interleukin-6, not tumor necrosis factor-α and interferon γ induced the LRG1 expression in human renal tubular epithelial cell line. Moreover, stimulation of recombinant human LRG1 could inhibit late apoptosis, promote proliferation and regulate expression of inflammatory factors and cytokines.

CONCLUSIONS

Plasma expression levels of LRG1 were associated with renal function, disease activity, and pathology in LN. It might also be involved in renal inflammation, proliferation and apoptosis of endothelial cells. LRG1 might be a potential prognosis novel predictor in LN patients.

Changes in acute blood purification therapy in critical care: republication of the article published in the Japanese Journal of Artificial Organs

Acute blood purification therapy is an essential artificial organ in critical care. In the review article, looking back on the history, we describe our present knowledge and techniques of acute blood purification therapy in critical care. The topics include continuous hemodiafiltration (CHDF), online HDF as an artificial liver support, blood purification therapy aiming to remove pathogenic substances of sepsis, a procedure for connecting a CRRT device into an extra-corporeal membrane oxygenation circuit, and replacement fluid for CHDF. We also raise remaining issues and clarify the future direction of acute blood purification therapy in critical care. This review was created based on a translation of the Japanese review written in the Japanese Journal of Artificial Organs in 2017 (Vol. 46, No. 1, pp. 67-70), with adding some references.