Neutrophil gelatinase-associated lipocalin in normal and neoplastic human tissues. Cell type-specific pattern of expression

Research on LCN2 interference to enhance the sensitivity of drug-resistant strains to gemcitabine

The aim of this study was to observe the sensitivity of the resistant strains to gemcitabine by interfering with the LCN2.An AsPC-1 gemcitabine-resistant cell line (GEM-R) was generated. Based on GEM-R, a lentivirus-infected shRNA-transfected LCN2 cell line was established. The proliferation of LCN2-regulated GEM-R cells was evaluated using the CCK-8 test and the mRNA expression of Ki-67. The apoptosis level of each drug-resistant strain was detected by flow cytometry. The expression of Bax, Bcl-2, Akt, E-cadherin and Vimentin were detected by western blotting.A gemcitabine-resistant strain of AsPC-1 was successfully induced and constructed as an shRNA LCN2 strain based on GEM-R. The interference of LCN2 expression enhanced the tumour inhibition and pro-apoptotic level of gemcitabine, increased the Bax/Bcl-2 value, and decreased p-Akt/Akt value. Meanwhile, the expression of E-cadherin was enhanced while the expression of Vimentin was decreased.This study confirmed that LCN2 affects gemcitabine sensitivity by participating in apoptosis and EMT processes, which may provide potential for overcoming gemcitabine resistance.

The lipocalin saga: Insights into its role in cancer-associated cachexia

Cancer-associated cachexia (CAC) is a debilitating condition, observed in patients with advanced stages of cancer. It is marked by ongoing weight loss, weakness, and nutritional impairment. Lower tolerance of chemotherapeutic agents and radiation therapy makes it difficult to treat CAC. Anorexia is a significant contributor to worsening CAC. Anorexia can be found in the early or advanced stages of cancer. Anorexia in cancer patients arises from a confluence of factors. Tumor-related inflammatory cytokines can directly impact the gastrointestinal tract, leading to dysphagia and compromised gut function. Additionally, increased serotonin and hormonal disruptions lead to early satiety, suppressing appetite. Due to the complexities in the pathogenesis of the disease, identifying druggable targets is a challenge. Research is ongoing to identify novel targets for the treatment of this condition. Recent research suggests a potential link between elevated levels of Lipocalin 2 (LCN2) and cachexia in cancer patients. LCN2, a glycoprotein primarily released by neutrophils, is implicated in numerous illnesses, including skin disorders, cancer, atherosclerosis, and type 2 diabetes. LCN2 suppresses hunger by binding to the melanocortin-4 receptors. Several in vitro, in vivo, and clinical studies indicate the association between LCN2 levels and appetite suppression. Further research should be explored emphasizing the significance of well-crafted clinical trials to confirm LCN2's usefulness as a therapeutic target and its ability to help cancer patients who are suffering from the fatal hallmark of cachexia. This review explores LCN2's function in the multifaceted dynamics of CAC and anorexia.

Hematologic cancers and infections: how to detect infections in advance and determine the type?

Infection is one of the leading causes of death in patients with hematologic cancers. Hematologic cancer patients with compromised immune systems are already susceptible to infections, which come on even more rapidly and are difficult to control after they develop neutrophil deficiencies from high-dose chemotherapy. After patients have developed an infection, the determination of the type of infection becomes a priority for clinicians. In this review, we summarize the biomarkers currently used for the prediction of infections in patients with hematologic cancers; procalcitonin, CD64, cytokines, and CD14 et al. can be used to determine bacterial infections, and (1-3)-β-D-glucan and galactomannan et al. can be used as a determination of fungal infections. We have also focused on the use of metagenomic next-generation sequencing in infections in patients with hematologic cancers, which has excellent clinical value in infection prediction and can detect microorganisms that cannot be detected by conventional testing methods such as blood cultures. Of course, we also focused on infection biomarkers that are not yet used in blood cancer patients but could be used as a future research direction, e.g., human neutrophil lipocalin, serum amyloid A, and heparin-binding protein et al. Finally, clinicians need to combine multiple infection biomarkers, the patient's clinical condition, local susceptibility to the type of infection, and many other factors to make a determination of the type of infection.

Associations between plasma markers and symptoms of anxiety and depression in patients with breast cancer

BACKGROUND AND PURPOSE

Among patients with solid tumors, those with breast cancer (BC) experience the most severe psychological issues, exhibiting a high global prevalence of depression that negatively impacts prognosis. Depression can be easily missed, and clinical markers for its diagnosis are lacking. Therefore, this study in order to investigate the diagnostic markers for BC patients with depression and anxiety and explore the specific changes of metabolism.

METHOD AND RESULTS

Thirty-eight BC patients and thirty-six matched healthy controls were included in the study. The anxiety and depression symptoms of the participants were evaluated by the 17-item Hamilton Depression Scale (HAMD-17) and Hamilton Anxiety Scale (HAMA). Plasma levels of glial fibrillary acidic protein (GFAP) and lipocalin-2 (LCN2) were evaluated using enzyme linked immunosorbent assay, and plasma lactate levels and metabolic characteristics were analyzed.

CONCLUSION

This study revealed that GFAP and LCN2 may be good diagnostic markers for anxiety or depression in patients with BC and that plasma lactate levels are also a good diagnostic marker for anxiety. In addition, specific changes in metabolism in patients with BC were preliminarily explored.

IL-17 Mildly Rescued the Impaired Proliferation of Alveolar Epithelial Cells Induced by LCN2 Overexpression

Introduction

The impaired proliferative capacity of alveolar epithelial cells after injury is an important factor causing epithelial repair dysfunction, leading to the occurrence of idiopathic pulmonary fibrosis (IPF). Alveolar type 2 (AT2) cells as the stem cells of alveolar epithelium participate in the repair process after alveolar injury. Lipocalin-2 (LCN2) participates in multiple processes regulating the pathological process of alveolar epithelial cells, but the mechanisms involved are still unclear.

Method

We used a BLM-treated mouse model to characterize the expression of LCN2 in lung fibrosis regions and analyzed the location of LCN2 in alveolar epithelial cells. Moreover, human pulmonary alveolar epithelial cells (HPAEpiCs) were transfected with the LCN2 overexpression plasmid vector in vitro. Recombinant human interleukin-17 (IL-17) protein (rhIL-17) at different concentrations was administered to intervene in HPAEpiCs, observing cell viability and analyzing the concentration-dependent effect of IL-17.

Results

LCN2 was increased in the alveolar epithelium post-BLM injury, and highly expressed LCN2 was mainly concentrated on AT2 cells in BLM-injured lungs. Meanwhile, LCN2-overexpressing HPAEpiCs showed impaired cell viability and cell growth. HPAEpiC intervention with rhIL-17 mildly rescued the impaired cell proliferation induced by LCN2 overexpression, and the effect of IL-17 intervention was partially concentration-dependent.

Conclusions

The results revealed the reversed effect of IL-17 on the impaired proliferative capacity of the alveolar epithelium induced by LCN2 overexpression. The target alveolar epithelial cells regulated by this process were AT2 cells, providing new clues for alveolar epithelium repair after injury and the treatment of lung injury diseases.

The Need to Identify Novel Markers for Early Renal Injury in Cardiorenal Syndrome

The term "Cardiorenal Syndrome" (CRS) refers to the complex interplay between heart and kidney dysfunction. First described by Robert Bright in 1836, CRS was brought to its modern view by Ronco et al. in 2008, who defined it as one organ's primary dysfunction leading to secondary dysfunction in the other, a view that led to the distinction of five different types depending on the organ of primary dysfunction and the temporal pattern (acute vs. chronic). Their pathophysiology is intricate, involving various hemodynamic, neurohormonal, and inflammatory processes that result in damage to both organs. While traditional biomarkers have been utilized for diagnosing and prognosticating CRS, they are inadequate for the early detection of acute renal damage. Hence, there is a pressing need to discover new biomarkers to enhance clinical outcomes and treatment approaches.

Overview of the expression patterns and roles of Lipocalin 2 in the reproductive system

The 25 kDa-sized protein Lipocalin 2 (LCN2) was originally isolated from human neutrophil granulocytes more than 30 years ago. LCN2 is an emerging player in innate immune defense, as it reduces bacterial growth due to its ability to sequester iron-containing bacterial siderophores. On the other hand, LCN2 also serves as a transporter for various hydrophobic substances due to its β-barrel shaped structure. Over the years, LCN2 has been detected in many other cell types including epithelial cells, astrocytes, and hepatocytes. Studies have clearly shown that aberrant expression of LCN2 is associated with a variety of disorders and malignancies, including several diseases of the reproductive system. Furthermore, LCN2 was proposed as a non-invasive prognostic and/or diagnostic biomarker in this context. Although several studies have shed light on the role of LCN2 in various disorders of the female and male reproductive systems, including tumorigenesis, a comprehensive understanding of the physiological function of LCN2 in the reproductive tract is still lacking. However, there is evidence that LCN2 is directly related to fertility, as global depletion of Lcn2 in mice has a negative effect on their pregnancy rate. Since LCN2 expression can be regulated by steroid hormones, it is not surprising that its expression fluctuates greatly during remodeling processes in the female reproductive tract, especially in the uterus. Well-founded details about the expression and regulation of LCN2 in a healthy reproductive state and also about possible changes during reproductive aging could contribute to a better understanding of LCN2 as a target in various diseases. Therefore, the present review summarizes current knowledge about LCN2 in the reproductive system, including studies in rodents and humans, and discusses changes in LCN2 expression during pathological events. The limited data suggest that LCN2 is expressed and regulated differently in healthy male and female reproductive organs.

Neutrophil Gelatinase-Associated Lipocalin as a Biomarker in Post-Acute COVID-19 Syndrome

Background: Neutrophil gelatinase-associated lipocalin (NGAL) is part of the innate immune system and acute-phase protein. Current data state that acute COVID-19 patients have higher levels of serum NGAL (sNGAL), but it is not known if higher protein levels are maintained in the convalescents. As post-COVID complications are currently the most important aspect of the disease, further research into metabolic and immunological consequences of the disease is needed. Methods: We aimed to determine the levels of sNGAL in a patient population 3 months after the acute phase of the disease and to identify the factors that may be related to the elevation of sNGAL levels in the mentioned cohort. The study included 146 patients diagnosed with COVID-19 in different stages of the disease. Three months after COVID-19 diagnosis, patients' sera were sampled and tested. Results: We demonstrate an association between the severity of the disease in the acute phase and elevated sNGAL levels three months after recovery, with the exception of the most severe hospitalized patients, who received early treatment. Moreover, we establish that sNGAL levels could be associated with prolonged dyspnea and the regulation of hunger and satiety in COVID-19 convalescents. Conclusions: These observations support the view that the introduction of antiviral treatment, steroids, and intense oxygen therapy reduces post-COVID immune-associated complications.

Lipocalin 2 (LCN2) confers acquired resistance to almonertinib in NSCLC through LCN2-MMP-9 signaling pathway

Almonertinib, a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, is highly selective for EGFR-activating mutations as well as the EGFR T790M mutation in patients with advanced non-small cell lung cancer (NSCLC). However, the development of resistance inevitably occurs and poses a major obstacle to the clinical efficacy of almonertinib. Therefore, a clear understanding of the mechanism is of great significance to overcome drug resistance to almonertinib in the future. In this study, NCI-H1975 cell lines resistant to almonertinib (NCI-H1975 AR) were developed by concentration-increasing induction and were employed for clarification of underlying mechanisms of acquired resistance. Through RNA-seq analysis, the HIF-1 and TGF-β signaling pathways were significantly enriched by gene set enrichment analysis. Lipocalin-2 (LCN2), as the core node in these two signaling pathways, were found to be positively correlated to almonertinib-resistance in NSCLC cells. The function of LCN2 in the drug resistance of almonertinib was investigated through knockdown and overexpression assays in vitro and in vivo. Moreover, matrix metalloproteinases-9 (MMP-9) was further identified as a critical downstream effector of LCN2 signaling, which is regulated via the LCN2-MMP-9 axis. Pharmacological inhibition of MMP-9 could overcome resistance to almonertinib, as evidenced in both in vitro and in vivo models. Our findings suggest that LCN2 was a crucial regulator for conferring almonertinib-resistance in NSCLC and demonstrate the potential utility of targeting the LCN2-MMP-9 axis for clinical treatment of almonertinib-resistant lung adenocarcinoma.

Plasma NGAL levels in stable kidney transplant recipients and the risk of allograft loss

BACKGROUND

The objective of this study was to investigate the utility of neutrophil gelatinase-associated lipocalin (NGAL) and calprotectin (CPT) to predict long-term graft survival in stable kidney transplant recipients (KTR).

METHODS

A total of 709 stable outpatient KTR were enrolled >2 months post-transplant. The utility of plasma and urinary NGAL (pNGAL, uNGAL) and plasma and urinary CPT at enrollment to predict death-censored graft loss was evaluated during a 58-month follow-up.

RESULTS

Among biomarkers, pNGAL showed the best predictive ability for graft loss and was the only biomarker with an area under the curve (AUC) > 0.7 for graft loss within 5 years. Patients with graft loss within 5 years (n = 49) had a median pNGAL of 304 [interquartile range (IQR) 235-358] versus 182 (IQR 128-246) ng/mL with surviving grafts (P < .001). Time-dependent receiver operating characteristic analyses at 58 months indicated an AUC for pNGAL of 0.795, serum creatinine-based Chronic Kidney Disease Epidemiology Collaboration estimated glomerular filtration rate (eGFR) had an AUC of 0.866. pNGAL added to a model based on conventional risk factors for graft loss with death as competing risk (age, transplant age, presence of donor-specific antibodies, presence of proteinuria, history of delayed graft function) had a strong independent association with graft loss {subdistribution hazard ratio (sHR) for binary log-transformed pNGAL [log2(pNGAL)] 3.4, 95% confidence interval (CI) 2.24-5.15, P < .0001}. This association was substantially attenuated when eGFR was added to the model [sHR for log2(pNGAL) 1.63, 95% CI 0.92-2.88, P = .095]. Category-free net reclassification improvement of a risk model including log2(pNGAL) in addition to conventional risk factors and eGFR was 54.3% (95% CI 9.2%-99.3%) but C-statistic did not improve significantly.

CONCLUSIONS

pNGAL was an independent predictor of renal allograft loss in stable KTR from one transplant center but did not show consistent added value when compared with baseline predictors including the conventional marker eGFR. Future studies in larger cohorts are warranted.

The Value of Urinary NGAL, KIM-1, and IL-18 Measurements in the Early Detection of Kidney Injury in Oncologic Patients Treated with Cisplatin-Based Chemotherapy

Cisplatin is still a widely used anticancer drug characterized by significant nephrotoxicity. Acute kidney injury (AKI), diagnosed based on the Kidney Disease: Improving Global Outcomes (KDIGO) criteria, has limitations, including a delayed increase in creatinine. We determined the usefulness of neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), and interleukin-18 (IL-18) in diagnosing AKI according to the KDIGO criteria in patients treated with cisplatin. We recruited 21 subjects starting cisplatin-based chemotherapy (Cisplatin-based group) and 11 treated with carboplatin-based chemotherapy or 5-fluorouracil regimens (non-cisplatin-based group). Blood and urine samples were collected during four subsequent cycles of chemotherapy (68 and 38 cycles, respectively). AKI occurred in four patients in the cisplatin-based group (5.9% of 68 cisplatin-based chemotherapy cycles). Among them, three urinary markers were increased by over 100% in two cases, two in one case and one in another. A doubling of at least one investigated parameter was observed more frequently during cisplatin-based chemotherapy (80.3% vs. 52.8%; OR = 3.65, 95% CI: 1.49-8.90; p < 0.01). The doubling of at least one new urinary AKI marker was more common in patients receiving cisplatin and frequently was not associated with overt AKI. Thus, a subclinical kidney injury detected by these markers occurs more frequently than deterioration in kidney function stated with creatinine changes.

Interaction between serum neutrophil gelatinase associated lipocalin and visceral fat area on cardiovascular health in a cohort of community-based individuals

BACKGROUND

We assessed the predictive values of neutrophil gelatinase-associated lipocalin (NGAL), fat distribution, and their interaction on the development of major adverse cardiovascular events (MACE) in a community-based cohort of middle-aged and older individuals.

METHODS

This prospective study involved 1349 adults (43.2% men) aged 50-80 y, without baseline cardiovascular diseases, from communities in 2013-2014. All participants were followed up for a mean of 7.6 y via phone calls and medical records. Serum NGAL concentrations were analyzed at baseline. Fat distribution, including subcutaneous fat area and visceral fat area (VFA), was assessed by magnetic resonance imaging.

RESULTS

In fully-adjusted Cox regression models, baseline high NGAL concentrations were related to an increased risk of MACE in women [HR 1.75, 95% CI 1.03-2.99], compared with low NGAL concentrations. After stratification by VFA concentrations, the observed association was more predominant in women with baseline low VFA (HR 1.24, 95% CI 1.11-1.38). Moreover, the association between NGAL and MACE was interacted by VFA, strengthening the association at low VFA concentrations (Pinteraction < 0.05).

CONCLUSIONS

Serum NGAL determined at baseline predicts the development of MACE, and the association is modified by VFA in women.

Gene network based analysis identifies a coexpression module involved in regulating plasma lipids with high-fat diet response

Plasma lipids are modulated by gene variants and many environmental factors, including diet-associated weight gain. However, understanding how these factors jointly interact to influence molecular networks that regulate plasma lipid levels is limited. Here, we took advantage of the BXD recombinant inbred family of mice to query weight gain as an environmental stressor on plasma lipids. Coexpression networks were examined in both nonobese and obese livers, and a network was identified that specifically responded to the obesogenic diet. This obesity-associated module was significantly associated with plasma lipid levels and enriched with genes known to have functions related to inflammation and lipid homeostasis. We identified key drivers of the module, including Cidec, Cidea, Pparg, Cd36, and Apoa4. The Pparg emerged as a potential master regulator of the module as it can directly target 19 of the top 30 hub genes. Importantly, activation of this module is causally linked to lipid metabolism in humans, as illustrated by correlation analysis and inverse-variance weighed Mendelian randomization. Our findings provide novel insights into gene-by-environment interactions for plasma lipid metabolism that may ultimately contribute to new biomarkers, better diagnostics, and improved approaches to prevent or treat dyslipidemia in patients.

Screening and identification of the core immune-related genes and immune cell infiltration in severe burns and sepsis

Severe burns often have a high mortality rate due to sepsis, but the genetic and immune crosstalk between them remains unclear. In the present study, the GSE77791 and GSE95233 datasets were analysed to identify immune-related differentially expressed genes (DEGs) involved in disease progression in both burns and sepsis. Subsequently, weighted gene coexpression network analysis (WGCNA), gene enrichment analysis, protein-protein interaction (PPI) network construction, immune cell infiltration analysis, core gene identification, coexpression network analysis and clinical correlation analysis were performed. A total of 282 common DEGs associated with burns and sepsis were identified. Kyoto Encyclopedia of Genes and Genomes pathway analysis identified the following enriched pathways in burns and sepsis: metabolic pathways; complement and coagulation cascades; legionellosis; starch and sucrose metabolism; and ferroptosis. Finally, six core DEGs were identified, namely, IL10, RETN, THBS1, FGF13, LCN2 and MMP9. Correlation analysis showed that some core DEGs were significantly associated with simultaneous dysregulation of immune cells. Of these, RETN upregulation was associated with a worse prognosis. The immune-related genes and dysregulated immune cells in severe burns and sepsis provide potential research directions for diagnosis and treatment.

Remove, Refine, Reduce: Cell Death in Biological Systems

Cell death is an important biological phenomenon [...].

Clinical significance of neutrophil gelatinase-associated lipocalin and sdLDL-C for coronary artery disease in patients with type 2 diabetes mellitus aged ≥ 65 years

BACKGROUND AND AIMS

Although type 2 diabetes mellitus (T2DM) and coronary artery disease (CAD) share many common pathological and physiological characteristics, there are few studies assessing the predictive capacity of novel biomarkers in occurrence and development of CAD in T2DM patients aged ≥ 65 years. In addition, T2DM patients aged ≥ 65 years are prone to CAD. Therefore, it is of great significance to find novel biomarkers for the development CAD in T2DM.

METHODS

In this retrospective cohort study, 579 T2DM patients aged ≥ 65 years were consecutively enrolled in this work, and 177 of whom had major adverse cardiovascular and cerebrovascular events (MACCE: cardiovascular or cerebrovascular death, acute coronary syndrome, coronary stent implantation, and stroke) during the follow up. Univariate and multivariate factors were employed to analyze the correlation between each variable and the occurrence of MACCE, and the Spearman's rank correlation analysis was performed to assess the relationships between Neutrophil gelatinase-associated lipocalin (NGAL) and small dense low-density lipoprotein-cholesterol (LDL-C) (sdLDL-C). The receiver operating characteristic (ROC) curve was adopted to determine the predictive value of NGAL and sdLDL-C elevation for MACCE in T2DM patients aged ≥ 65 years.

RESULTS

After a median 48 months follow-up [19, (10 ~ 32) ], the levels of NGAL, sdLDL-C, hemoglobin A1c (HbA1c), LDL-C, and apolipoprotein B (ApoB) were significantly higher while those of high-density lipoprotein cholesterol (HDL-C) and apolipoprotein A I (ApoA-I) were lower in MACCE positive group. NGAL correlated to body mass index (BMI) (r = 0.391, P = 0.001) and triglyceride (TG) (r = 0.228, P = 0.032), and high-sensitivity CRP (hsCRP) (r = 0.251, P = 0.007), and neutrophils (r = 0.454, P = 0.001), sdlDL-C level was found to be positively correlated with LDL-C (r = 0.413, P = 0.001), TG (r = 0.432, P = 0.001), and ApoB (r = 0.232, P = 0.002); and it was negatively correlated with HDL-C (r = -0.362, P = 0.031) and ApoA-I (r = -0.402, P = 0.001). Age-adjusted Cox regression analysis showed that NGAL (HR = 1.006, 95% confidence interval (CI): 1.005-1.008, P < 0.001) and sdLDL-C (HR = 1.052, 95% CI: 1.037-1.066, P < 0.001) were independently associated with occurrence of MACCE. ROC curve analysis showed that NGAL (area under ROC (AUC) = 0.79, 95% CI: 0.75-0.84, P < 0.001) and sdlDL-C (AUC = 0.76, 95% CI: 0.72-0.80, P < 0.001) could predict the occurrence of MACCE (area under ROC. NGAL combined with sdlDL-C could predict the occurrence of MACCE well (AUC = 0.87, 95% CI: 0.84-0.90, P < 0.001).

CONCLUSION

The higher NGAL and sdLDL-C in T2DM patients aged ≥ 65 years were significantly and independently associated with the risk of MACCE, and showed higher clinical values than other lipid biomarkers or other chronic inflammation, so they were expected to be the most effective predictors of MACCE assessment.

Emerging biomarkers for the detection of cardiovascular diseases

Background

The prevalence of cardiovascular disease (CVD) has been continuously increasing, and this trend is projected to continue. CVD is rapidly becoming a significant public health issue. Every year there is a spike in hospital cases of CVD, a critical health concern in lower- and middle-income countries. Based on identification of novel biomarkers, it would be necessary to study and evaluate the diagnostic requirements or CVD to expedite early detection.

Main body

The literature review was written using a wide range of sources, such as well-known medical journals, electronic databases, manuscripts, texts, and other writings from the university library. After that, we analysed the specific markers of CVD and compiled a systematic review. A growing body of clinical research aims to identify people who are at risk for cardiovascular disease by looking for biomolecules. A small number of biomarkers have been shown to be useful and reliable in medicine. Biomarkers can be used for a variety of clinical applications, such as predicting heart disease risk, diagnosing disease, or predicting outcomes. As a result of the ability for a single molecule to act as a biomarker, its usefulness in medicine is expected to increase significantly.

Conclusions

Based on assessing the current trends in the application of CVD markers, we discussed and described the requirements for the application of CVD biomarkers in coronary heart disease, cerebrovascular disease, rheumatic heart disease, and other cardiovascular illnesses. Furthermore, the current review focuses on biomarkers for CVD and the procedures that should be considered to establish the comprehensive nature of the expression of biomarkers for cardiovascular illness.

Advances in the study of subclinical AKI biomarkers

Acute kidney injury (AKI) is a prevalent and serious illness in all clinical departments, with a high morbidity and death rate, particularly in intensive care units, where prevention and treatment are crucial. As a result, active prevention, early detection, and timely intervention for acute kidney injury are critical. The current diagnostic criteria for acute kidney injury are an increase in serum creatinine concentration and/or a decrease in urine output, although creatinine and urine output merely reflect changes in kidney function, and AKI suggests injury or damage, but not necessarily dysfunction. The human kidney plays a crucial functional reserve role, and dysfunction is only visible when more than half of the renal mass is impaired. Tubular damage markers can be used to detect AKI before filtration function is lost, and new biomarkers have shown a new subset of AKI patients known as "subclinical AKI." Furthermore, creatinine and urine volume are only marginally effective for detecting subclinical AKI. As a result, the search for new biomarkers not only identifies deterioration of renal function but also allows for the early detection of structural kidney damage. Several biomarkers have been identified and validated. This study discusses some of the most promising novel biomarkers of AKI, including CysC, NGAL, KIM-1, lL-18, L-FABP, IGFBP7, TIMP-2, Clusterin, and Penkid. We examine their performance in the diagnosis of subclinical AKI, limitations, and future clinical practice directions.

Lipocalin 2 attenuates oligodendrocyte loss and immune cell infiltration in mouse models for multiple sclerosis

Multiple sclerosis (MS) is a central nervous system disease characterized by both degenerative and inflammatory processes. Various mediators are involved in the interplay of degeneration and innate immunity on one hand and peripheral adaptive immunity on the other hand. The secreted protein lipocalin 2 (LCN2) is an inflammatory modulator in a variety of pathologies. Although elevated intrathecal levels of LCN2 have been reported in MS patients, it's functional role is widely unknown. Here, we identified a subpopulation of astrocytes as a source of LCN2 in MS lesions and respective animal models. We investigated the functional role of LCN2 for both autoimmune and degenerative aspects in three MS mouse models including both wild type (WT) and Lcn2^-/- mouse strains. While the experimental autoimmune encephalomyelitis (EAE) model reflects primary autoimmunity, the cuprizone model reflects selective oligodendrocyte loss and demyelination. In addition, we included a combinatory Cup/EAE model in which primary cytodegeneration is followed by inflammatory lesions within the forebrain. While in the EAE model, the disease outcome was comparable in between the two mouse strains, cuprizone intoxicated Lcn2^-/- animals showed an increased loss of oligodendrocytes. In the Cup/EAE model, Lcn2^-/- animals showed increased inflammation when compared to WT mice. Together, our results highlight LCN2 as a potentially protective molecule in MS lesion formation, which might be able to limit loss of oligodendrocytes immune-cell invasion. Despite these findings, it is not yet clear which glial cell phenotype (and to which extent) contributes to the observed neuroprotective effects, that is, microglia and/or astroglia or even endothelial cells in the brain.

A study on bisphenol S induced nephrotoxicity and assessment of altered downstream kidney metabolites using gas chromatography-mass spectrometry based metabolomics

The global use of bisphenol S (BPS) has now been significantly increased for commensurate utilization as a substitute for BPA for its regulatory concerns. Though, previous reports indicated that BPS been also appeared as a toxic congener comparable to BPA. In the present study, we determined nephrotoxicity condition induced due to BPS exposure. Results indicated that BPS significantly promoted histopathological disturbance in the kidney, and altered the levels of biomarkers of kidney damage in serum and urine samples of Wistar rats. It is also indicated that BPS altered the expression of kidney damage biomarkers associated with glomerular and tubular injury. Additionally, we determined the perturbation of kidney metabolites in the underlying pathophysiological response of kidney injury due to BPS exposure. Gas chromatography-mass spectrometry based untargeted metabolomics exhibited 20 significantly perturbed metabolites. Moreover, metabolic pathway analysis revealed significant disturbance in the TCA cycle and pyruvate metabolism pathways.

Ferric Citrate Uptake Is a Virulence Factor in Uropathogenic Escherichia coli

More than half of women will experience a urinary tract infection (UTI), with uropathogenic Escherichia coli (UPEC) causing ~80% of uncomplicated cases. Iron acquisition systems are essential for uropathogenesis, and UPEC strains encode highly diverse iron acquisition systems, underlining their importance. However, a recent UPEC clinical isolate, HM7, lacks this diversity and instead encodes the synthesis pathway for a sole siderophore, enterobactin. To determine if HM7 possesses unidentified iron acquisition systems, we performed RNA sequencing under iron-limiting conditions and demonstrated that the ferric citrate uptake system (fecABCDE and fecIR) was highly upregulated. Importantly, there are high levels of citrate within urine, some of which is bound to iron, and the fec system is enriched in UPEC isolates compared to fecal strains. Therefore, we hypothesized that HM7 and other similar strains use the fec system to acquire iron in the host. Deletion of both enterobactin biosynthesis and ferric citrate uptake (ΔfecA/ΔentB) abrogates use of ferric citrate as an iron source, and fecA provides an advantage in human urine in the absence of enterobactin. However, in a UTI mouse model, fecA is a fitness factor independent of enterobactin production, likely due to the action of host lipocalin-2 chelating ferrienterobactin. These findings indicate that ferric citrate uptake is used as an iron source when siderophore efficacy is limited, such as in the host during UTI. Defining these novel compensatory mechanisms and understanding the nutritional hierarchy of preferred iron sources within the urinary tract are important in the search for new approaches to combat UTI.

Effects of combined administration of doxorubicin and chloroquine on lung pathology in mice with solid Ehrlich ascites carcinoma

Combined use of a chemotherapeutic agent and an autophagy inhibitor is a novel cancer treatment strategy. We investigated the effects of chloroquine (CQ) on lung pathology caused by both solid Ehrlich ascites carcinoma (EAC) and doxorubicin (DXR). A control group and eight experimental groups of adult female mice were inoculated subcutaneously with 2.5 × 10⁶ EAC cells. DXR (1.5 mg/kg and 3 mg/kg) and CQ (25 mg/kg and 50 mg/kg) alone or in combination were injected intraperitoneally on days 2, 7 and 12 following inoculation with EAC cells. Lung tissue samples were examined using immunohistochemistry (IHC) for endothelial (eNOS), inducible nitric oxide synthase (iNOS) and neutrophil gelatinase-associated lipocalin (NGAL). Serum catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD) and malondialdehyde (MDA) levels were measured using ELISA. We found decreased levels of iNOS and eNOS in the groups that received 1.5 mg/kg DXR alone and in combination with 25 mg/kg and 50 mg/kg CQ. Combined administration of DXR and CQ partially prevented disruption of alveolar structure. Levels of antioxidant enzymes and MDA were lower in all treated groups; the greatest reduction was observed in mice that received the combination of 25 mg/kg CQ + 1.5 mg/kg DXR. Levels of NGAL were elevated in all treated groups. We found that CQ ameliorated both EAC and DOX induced lung pathology in female mice with solid EAC by reducing oxidative stress.

Renal biomarkers in cats: A review of the current status in chronic kidney disease

Serum creatinine concentration, the classical biomarker of chronic kidney disease (CKD) in cats, has important limitations that decrease its value as a biomarker of early CKD. Recently, serum symmetric dimethylarginine concentration was introduced as a novel glomerular filtration rate biomarker for the early detection of CKD in cats. However, data on its specificity are still limited. The limitations of conventional biomarkers and the desire for early therapeutic intervention in cats with CKD to improve outcomes have prompted the discovery and validation of novel renal biomarkers to detect glomerular or tubular dysfunction. Changes in the serum or urinary concentrations of these biomarkers may indicate early kidney damage or predict the progression of kidney before changes in conventional biomarkers are detectable. This review summarizes current knowledge on renal biomarkers in CKD in cats, a field that has progressed substantially over the last 5 years.

Role of confirmed and potential predictors of an unfavorable outcome in heart failure in everyday clinical practice

Heart failure (HF) is the only cardiovascular disease with an ever increasing incidence. HF, through reduced functional capacity, frequent exacerbations of disease, and repeated hospitalizations, results in poorer quality of life, decreased work productivity, and significantly increased costs of the public health system. The main challenge in the treatment of HF is the availability of reliable prognostic models that would allow patients and doctors to develop realistic expectations about the prognosis and to choose the appropriate therapy and monitoring method. At this moment, there is a lack of universal parameters or scales on the basis of which we could easily capture the moment of deterioration of HF patients' condition. Hence, it is crucial to identify such factors which at the same time will be widely available, cheap, and easy to use. We can find many studies showing different predictors of unfavorable outcome in HF patients: thorough assessment with echocardiography imaging, exercise testing (e.g., 6-min walk test, cardiopulmonary exercise testing), and biomarkers (e.g., N-terminal pro-brain type natriuretic peptide, high-sensitivity troponin T, galectin-3, high-sensitivity C-reactive protein). Some of them are very promising, but more research is needed to create a specific panel on the basis of which we will be able to assess HF patients. At this moment despite identification of many markers of adverse outcomes, clinical decision-making in HF is still predominantly based on a few basic parameters, such as the presence of HF symptoms (NYHA class), left ventricular ejection fraction, and QRS complex duration and morphology.

Nouvelles approches diagnostiques de l’insuffisance rénale aiguë

L’insuffisance rénale, véritable problème de santé publique, concernerait plus de 82 000 personnes en France. On estime que 5 à 10 % de la population française souffriraient d’une maladie rénale pouvant conduire à une insuffisance rénale avec un taux de mortalité de plus de 10 % par an. À l’inverse de la maladie rénale chronique irréversible, l’insuffisance rénale aiguë est considérée comme un dysfonctionnement transitoire et réversible. Au-delà de l’intérêt de la prévention, le diagnostic précoce de l’insuffisance rénale aiguë permettrait de mettre en place des thérapeutiques adaptées et ciblées afin d’éviter l’évolution vers des lésions rénales irréversibles. Cependant, il demeure un véritable challenge pour le praticien puisque l’on présume que près de 10 % de la population française présenteraient des lésions rénales asymptomatiques. Bien que la définition de l’insuffisance rénale aiguë ait été simplifiée durant ces dernières années, il existe de nombreuses limites. En parallèle, des progrès majeurs ont été réalisés notamment en termes de diagnostic. L’objectif de cette mise au point est de faire un rappel sur l’évolution de l’insuffisance rénale aiguë, les définitions actuelles et de présenter les nouvelles approches diagnostiques en cours de développement.

Biomarkers in the clinical management of patients with atrial fibrillation and heart failure

Atrial fibrillation (AF) and heart failure (HF) are two cardiovascular diseases with an increasing prevalence worldwide. These conditions share common pathophysiologiesand frequently co-exit. In fact, the occurrence of either condition can 'cause' the development of the other, creating a new patient group that demands different management strategies to that if they occur in isolation. Regardless of the temproral association of the two conditions, their presence is linked with adverse cardiovascular outcomes, increased rate of hospitalizations, and increased economic burden on healthcare systems. The use of low-cost, easily accessible and applicable biomarkers may hasten the correct diagnosis and the effective treatment of AF and HF. Both AF and HF effect multiple physiological pathways and thus a great number of biomarkers can be measured that potentially give the clinician important diagnostic and prognostic information. These will then guide patient centred therapeutic management. The current biomarkers that offer potential for guiding therapy, focus on the physiological pathways of miRNA, myocardial stretch and injury, oxidative stress, inflammation, fibrosis, coagulation and renal impairment. Each of these has different utility in current clinincal practice.

Daily monitoring of viral load measured as SARS-CoV-2 antigen and RNA in blood, IL-6, CRP and complement C3d predicts outcome in patients hospitalized with COVID-19

OBJECTIVES

We hypothesized that the amount of antigen produced in the body during a COVID-19 infection might differ between patients, and that maximum concentrations would predict the degree of both inflammation and outcome for patients.

METHODS

Eighty-four hospitalized and SARS-CoV-2 PCR swab-positive patients, were followed with blood sampling every day until discharge or death. A total of 444 serial EDTA plasma samples were analyzed for a range of biomarkers: SARS-CoV-2 nuclear antigen and RNA concentration, complement activation as well as several inflammatory markers, and KL-6 as a lung marker. The patients were divided into outcome groups depending on need of respiratory support and death/survival.

RESULTS

Circulating SARS-CoV-2 nuclear antigen levels were above the detection limit in blood in 65 out of 84 COVID-19 PCR swab-positive patients on day one of hospitalization, as was viral RNA in plasma in 30 out of 84. In all patients, complete antigen clearance was observed within 24 days. There were definite statistically significant differences between the groups depending on their biomarkers, showing that the concentrations of virus RNA and antigen were correlated to the inflammatory biomarker levels, respiratory treatment and death.

CONCLUSIONS

Viral antigen is cleared in parallel with the virus RNA levels. The levels of antigens and SARS-CoV-2 RNA in the blood correlates with the level of IL-6, inflammation, respiratory failure and death. We propose that the antigens levels together with RNA in blood can be used to predict the severity of disease, outcome, and the clearance of the virus from the body.

Targeting Lipocalin-2 in Inflammatory Breast Cancer Cells with Small Interference RNA and Small Molecule Inhibitors

Inflammatory Breast Cancer (IBC) is an aggressive form of invasive breast cancer, highly metastatic, representing 2-4% of all breast cancer cases in the United States. Despite its rare nature, IBC is responsible for 7-10% of all breast cancer deaths, with a 5-year survival rate of 40%. Thus, targeted and effective therapies against IBC are needed. Here, we proposed Lipocalin-2 (LCN2)-a secreted glycoprotein aberrantly abundant in different cancers-as a plausible target for IBC. In immunoblotting, we observed higher LCN2 protein levels in IBC cells than non-IBC cells, where the LCN2 levels were almost undetectable. We assessed the biological effects of targeting LCN2 in IBC cells with small interference RNAs (siRNAs) and small molecule inhibitors. siRNA-mediated LCN2 silencing in IBC cells significantly reduced cell proliferation, viability, migration, and invasion. Furthermore, LCN2 silencing promoted apoptosis and arrested the cell cycle progression in the G0/G1 to S phase transition. We used in silico analysis with a library of 25,000 compounds to identify potential LCN2 inhibitors, and four out of sixteen selected compounds significantly decreased cell proliferation, cell viability, and the AKT phosphorylation levels in SUM149 cells. Moreover, ectopically expressing LCN2 MCF7 cells, treated with two potential LCN2 inhibitors (ZINC00784494 and ZINC00640089) showed a significant decrease in cell proliferation. Our findings suggest LCN2 as a promising target for IBC treatment using siRNA and small molecule inhibitors.

Lipocalin-2: a role in hepatic gluconeogenesis via AMP-activated protein kinase (AMPK)

PURPOSE

Evidence is accumulating that lipocalin2 (LCN2) is implicated in insulin resistance and glucose homeostasis, but the underlying possible mechanisms remain unclear. This study is to investigate the possible linkage between LCN2 and AMP-activated protein kinase (AMPK) or forkhead transcription factor O1 (FoxO1), which influences insulin sensitivity and gluconeogenesis in liver.

METHODS

LCN2 knockout (LCN2KO) mice and wild-type littermates were used to evaluate the effect of LCN2 on insulin sensitivity and hepatic gluconeogenesis through pyruvate tolerance test (PTT), glucose tolerance test (ipGTT), insulin tolerance test (ITT), and hyperinsulinemic-euglycemic clamps, respectively. LCN2KO mice and WT mice in vivo, and in vitro HepG2 cells were co-transfected with adenoviral FoxO1-siRNA (Ad-FoxO1-siRNA) or adenovirus expressing constitutively active form of AMPK (Ad-CA-AMPK), or dominant negative adenovirus AMPK (Ad-DN-AMPK), the relative mRNA and protein levels of two key gluconeogenic enzymes phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6P) were measured.

RESULTS

Improved insulin sensitivity and inhibited gluconeogenesis in the LCN2KO mice were confirmed by pyruvate tolerance tests and hyperinsulinemic-euglycemic clamps. Nuclear FoxO1 and its downstream genes PEECK and G6P were decreased in the livers of the LCN2KO mice, and AMPK activity was stimulated and directly phosphorylated FoxO1. In vitro, AMPK activity was inhibited in HepG2 cells overexpressing LCN2 leading to a decrease in phosphorylated FoxO1 and an increase in nuclear FoxO1.

CONCLUSION

The present study demonstrates that LCN2 regulates insulin sensitivity and glucose metabolism through inhibiting AMPK activity, and regulating FoxO1 and its downstream genes PEPCK/G6P, which regulate hepatic gluconeogenesis.

Neutrophils initiate and exacerbate Stevens-Johnson syndrome and toxic epidermal necrolysis

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are life-threatening mucocutaneous adverse drug reactions characterized by massive epidermal detachment. Cytotoxic T cells and associated effector molecules are known to drive SJS/TEN pathophysiology, but the contribution of innate immune responses is not well understood. We describe a mechanism by which neutrophils triggered inflammation during early phases of SJS/TEN. Skin-infiltrating CD8⁺ T cells produced lipocalin-2 in a drug-specific manner, which triggered the formation of neutrophil extracellular traps (NETs) in early lesional skin. Neutrophils undergoing NETosis released LL-37, an antimicrobial peptide, which induced formyl peptide receptor 1 (FPR1) expression by keratinocytes. FPR1 expression caused keratinocytes to be vulnerable to necroptosis that caused further release of LL-37 by necroptotic keratinocytes and induced FPR1 expression on surrounding keratinocytes, which likely amplified the necroptotic response. The NETs-necroptosis axis was not observed in less severe cutaneous adverse drug reactions, autoimmune diseases, or neutrophil-associated disorders, suggesting that this was a process specific to SJS/TEN. Initiation and progression of SJS/TEN keratinocyte necroptosis appear to involve a cascade of events mediated by innate and adaptive immune responses, and understanding these responses may contribute to the identification of diagnostic markers or therapeutic targets for these adverse drug reactions.

Prognostic Alternative Splicing Signatures in Esophageal Carcinoma

Alternative splicing (AS) is a method of increasing the number of proteins that the genome is capable of coding for, by altering the pre-mRNA during its maturation. This process provides the ability of a broad range of proteins to arise from a single gene. AS events are known to occur in up to 94% of human genes. Cumulative data have shown that aberrant AS functionality is a major factor in human diseases. This review focuses on the contribution made by aberrant AS functionality in the development and progression of esophageal cancer. The changes in the pattern of expression of alternately spliced isoforms in esophageal cancer can be used as diagnostic or prognostic biomarkers. Additionally, these can be used as targets for the development of new treatments for esophageal cancer.

Sepsis-Associated Acute Kidney Injury

Sepsis-associated acute kidney injury (S-AKI) is a common and life-threatening complication in hospitalized and critically ill patients. It is characterized by rapid deterioration of renal function associated with sepsis. The pathophysiology of S-AKI remains incompletely understood, so most therapies remain reactive and nonspecific. Possible pathogenic mechanisms to explain S-AKI include microcirculatory dysfunction, a dysregulated inflammatory response, and cellular metabolic reprogramming. In addition, several biomarkers have been developed in an attempt to improve diagnostic sensitivity and specificity of S-AKI. This article discusses the current understanding of S-AKI, recent advances in pathophysiology and biomarker development, and current preventive and therapeutic approaches.

May Neutrophil Gelatinase-Associated Lipocalin (NGAL) Level Predict Mortality in Patients with Hepatocellular Carcinoma (HCC)?

PURPOSE

Hepatocellular carcinoma (HCC) ranks fifth among the common cancers worldwide. Hepatocarcinogenesis is a multiple-phases process, which involves changes in cellular genomes including high cell proliferation.In this study, we aimed to evaluate the relationship of NGAL level at the time of diagnosis with mortality in patients diagnosed with HCC.

MATERIAL AND METHODS

A total of 35 patients who developed HCC on the ground of HBV(+) and 30 healthy subjects were included in the study. Barcelona Clinic Liver Cancer (BCLC), Okuda staging system, and Milan criteria were used for staging of the patients with HCC.

RESULTS

The mean age of all patients was 59.54 ± 11.57 years. Seventeen (48.6%) HCC patients died during 1-year follow-up. Survival of the patients who met the Milan criteria was longer (log-rank (Mantel-Cox) test, χ2 = 5.353, p = 0.021). Kaplan-Meier curve was drawn for NGAL cut-off value, mortality was found to be higher in patients with a NGAL level higher than 217.50 (log-rank (Mantel-Cox) test, χ2 = 15.540, p < 0.001).

CONCLUSION

In this study, we found that high levels of NGAL at the time of diagnosis were associated with poor prognosis in HCC patients.

[Expression and Clinical Significance of Lipocalin-2 in the Serum of Lung Cancer Patients]

背景与目的

肺癌是全球发病率最高的癌症类型，严重威胁着人类健康。肺癌的早期诊断、早期治疗对于肺癌患者的生存尤为重要。血清中的肿瘤标志物作为肿瘤早期诊断的一种重要方法已被广泛应用。然而，肺癌的早期诊断标志物还很少。本研究旨在探讨Lipocalin-2在肺癌患者血清中的表达水平及其临床意义。

方法

采用酶联免疫吸附法（enzyme linked immunosorbent assay, ELISA）检测Lipocalin-2在60例肺癌患者与63例健康人群外周血血清中的浓度，并分析Lipocalin-2表达水平与肺癌临床特征之间的关系。

结果

Lipocalin-2在肺癌患者外周血血清中的表达水平明显高于健康人群，差异具有明显统计学意义（P < 0.001）。Lipocalin-2在肺癌患者中的表达与病理组织的分化、分期及淋巴结转移相关，差异具有明显统计学意义（P < 0.05）。Lipocalin-2在病理分化差的肺癌患者血清中的表达高于分化良好患者；在发生淋巴结转移的肺癌患者血清中的表达高于没有发生淋巴结转移患者；在临床Ⅲ期+Ⅳ期肺癌患者中的表达水平显著高于临床Ⅰ期Ⅱ期患者；差异均具有统计学意义（P < 0.05）。

结论

Lipocalin-2在肺癌患者血清水平中高表达，与病理组织的分化、分期及淋巴结转移相关，有望成为一种潜在的用于临床诊断的新型肺癌肿瘤标志物。

A Review of Specific Biomarkers of Chronic Renal Injury and Their Potential Application in Nonclinical Safety Assessment Studies

A host of novel renal biomarkers have been developed over the past few decades which have enhanced monitoring of renal disease and drug-induced kidney injury in both preclinical studies and in humans. Since chronic kidney disease (CKD) and acute kidney injury (AKI) share similar underlying mechanisms and the tubulointerstitial compartment has a functional role in the progression of CKD, urinary biomarkers of AKI may provide predictive information in chronic renal disease. Numerous studies have explored whether the recent AKI biomarkers could improve upon the standard clinical biomarkers, estimated glomerular filtration rate (eGFR), and urinary albumin to creatinine ratio, for predicting outcomes in CKD patients. This review is an introduction to alternative assays that can be utilized in chronic (>3 months duration) nonclinical safety studies to provide information on renal dysfunction and to demonstrate specific situations where these assays could be utilized in nonclinical drug development. Novel biomarkers such as symmetrical dimethyl arginine, dickkopf homolog 3, and cystatin C predict chronic renal injury in animals, act as surrogates for GFR, and may predict changes in GFR in patients over time, ultimately providing a bridge from preclinical to clinical renal monitoring.

Role of neutrophil gelatinase-associated lipocalin in renal cell carcinoma

Human neutrophil gelatinase-associated lipocalin (NGAL) is a glycoprotein present in a wide variety of tissues and cell types. It exists as a monomer of 25 kDa, a homodimer of 45 kDa or a heterodimer of 135 kDa (disulfide bound to latent matrix metalloproteinase-9). NGAL is considered the biochemical gold standard for the early diagnosis of acute kidney injury and has attracted much attention as a diagnostic biomarker. NGAL has controversial (i.e. both beneficial and detrimental) effects on cellular processes associated with tumor development, such as cell proliferation, survival, migration, invasion and drug resistance. Therefore, the present review aimed at clarifying the role of NGAL in renal cell carcinoma (RCC). Relevant studies of NGAL and RCC were searched in PubMed and relevant information about the structure, expression, function and mechanism of NGAL in RCC were summarized. Finally, the following conclusions could be drawn from the literature: i) NGAL can be detected in cancer tissues, serum and urine of patients with RCC; ii) NGAL is not a suitable diagnostic marker for early screening of RCC; iii) NGAL expression may be used to predict the prognosis of patients with RCC; and iv) Further research on NGAL may be helpful to decrease sunitinib resistance and find new treatment strategies for RCC.

Sodium-glucose cotransporter 2 inhibition attenuates protein overload in renal proximal tubule via suppression of megalin O-GlcNacylation in progressive diabetic nephropathy

AIMS

The crosstalk between sodium-glucose cotransporter 2 (SGLT2) inhibition and a membrane-associated endocytic receptor megalin function involved in renal proximal tubular protein overload in progressive diabetic nephropathy (DN) is uncertain. Here, we determined whether SGLT2 inhibition affects megalin endocytic function through suppressing its O-linked β-N-acetylglucosamine modification (O-GlcNAcylation) and protects the diabetic kidney from protein overload.

MATERIALS AND METHOD

We treated 8-week-old male non-obese and hypoinsulinemic KK/Ta-Ins2^Akita (KK/Ta-Akita) mice which develop progressive DN with an SGLT2 inhibitor ipragliflozin or insulin for 6 weeks, and investigated the endocytic function (proximal tubular protein reabsorption), renal expression and O-GlcNAcylation of megalin along with their effects on renal phenotypes including histology and biochemical markers.

RESULTS

The treatment with ipragliflozin, but not insulin, suppressed megalin O-GlcNAcylation and accelerated its internalization, resulting in reduction in proximal tubular reabsorption of the highly filtered plasma proteins such as albumin and neutrophil gelatinase-associated lipocalin. These alterations following the ipragliflozin treatment contributed to amelioration of proximal tubular protein overload, mitochondrial morphological abnormality, and renal oxidative stress and tubulointerstitial fibrosis.

CONCLUSIONS

The present study provides a novel crosstalk mechanism between SGLT2 inhibition and megalin underlying the potential renal benefits of SGLT2 inhibition in DN.

Iron Dysregulation in Human Cancer: Altered Metabolism, Biomarkers for Diagnosis, Prognosis, Monitoring and Rationale for Therapy

Simple Summary

Iron is the more abundant metal ion in humans. It is essential for life as it has a role in various cellular processes involved, for instance, in cell metabolism and DNA synthesis. These functions are crucial for cell proliferation, and it is therefore not surprising that iron is accumulated in tumors. In this review, we describe normal and altered iron homeostasis mechanisms. We also provide a vision of iron-related proteins with altered expression in cancers and discuss their potential as diagnostic and/or prognostic biomarkers. Finally, we give an overview of therapeutic strategies acting on iron metabolism to fight against cancers.

Abstract

Iron (Fe) is a trace element that plays essential roles in various biological processes such as DNA synthesis and repair, as well as cellular energy production and oxygen transport, and it is currently widely recognized that iron homeostasis is dysregulated in many cancers. Indeed, several iron homeostasis proteins may be responsible for malignant tumor initiation, proliferation, and for the metastatic spread of tumors. A large number of studies demonstrated the potential clinical value of utilizing these deregulated proteins as prognostic and/or predictive biomarkers of malignancy and/or response to anticancer treatments. Additionally, the iron present in cancer cells and the importance of iron in ferroptosis cell death signaling pathways prompted the development of therapeutic strategies against advanced stage or resistant cancers. In this review, we select relevant and promising studies in the field of iron metabolism in cancer research and clinical oncology. Besides this, we discuss some co-existing discrepant findings. We also present and discuss the latest lines of research related to targeting iron, or its regulatory pathways, as potential promising anticancer strategies for human therapy. Iron chelators, such as deferoxamine or iron-oxide-based nanoparticles, which are already tested in clinical trials, alone or in combination with chemotherapy, are also reported.

Lipocalin2 promotes cell proliferation and migration in ovarian cancer through activation of the ERK/GSK3β/β-catenin signaling pathway

Lipocalin2 (Lcn2) has been shown to be a vital regulator of tumorigenesis in a variety of different cancers. However, its expression patterns and possible roles in ovarian cancer remain obscure. The aim of this study was to investigate the expression of Lcn2 in ovarian cancer cells and to determine any potential association between Lcn2 and ovarian tumor development and cancer progression. Our results indicated that Lcn2 was upregulated in tumor tissue from ovarian cancer patients as well as in three ovarian cancer cell lines compared to normal tissues and cells. Overexpression of Lcn2 promoted both cell proliferation and migration in ovarian cancer cells. Conversely, knockdown of Lcn2 in cell lines suppressed both migration and proliferation. Moreover, upregulation of Lcn2 contributed to tumor growth in nude mice in vivo. Mechanistically, Lcn2 was found to lead to tumor progression in ovarian cancer cells through activation of the ERK/GSK3β/β-catenin signaling pathway. In summary, Lcn2 promotes cell proliferation and migration in ovarian cancer through activation of the ERK/GSK3β/β-catenin signaling pathway, suggesting that Lcn2 might be a novel therapeutic target for ovarian cancer.

ARCHITECT® urine-neutrophil gelatinase-associated lipocalin (u-NGAL) assay as new prognostic marker for clear cell Renal Cell Carcinoma (ccRCC) (preliminary results)

INTRODUCTION

Biomarkers for the diagnosis and monitoring treatment response of kidney cancer are urgently needed. Neutrophil gelatinase-associated lipocalin (NGAL) is a relevant urinary biomarker for the diagnosis of a wide variety of acute and chronic kidney diseases. Its potential utility as a prognostic marker of kidney cancer is largely unknown and, therefore, was the subject of this investigation.

MATERIALS AND METHODS

A retrospective study was done on 50 kidney tumor patients (urine samples prospectively collected before nephrectomy between 2004 and 2012, stored at Biobank Resource Center). The specificity, sensitivity and the predictive value of NGAL were determined for progression-free and disease-specific survival after nephrectomy in renal cell carcinoma (particularly, the clear cell renal cell carcinoma (ccRCC)). Urinary NGAL concentration (u-NGAL) was determined by CMIA technique (ARCHITECT® urine NGAL essay/ABBOTT^®).

RESULTS

Out of the 50 kidney tumor patients, 40 had clear cell carcinoma with a median u-NGAL excretion of 1.4 (IQR: 5.76) ng/mg urinary creatinine (Ucr). u-NGAL was correlated to tumor stage (p = 0.005), and Fuhrman grade (p = 0.0002). Multivariate Cox regression analysis showed a significant association between u-NGAL excretion and clear cell renal cell carcinoma progression free survival and disease specific survival (p = 0.002; p = 0.0001).

CONCLUSIONS

Urinary NGAL was significantly associated with the stage and the grade of kidney cancer. u-NGAL excretion could be considered as a potential biomarker to identify ccRCC patients with the more pejorative outcomes.

Biological Functions and Therapeutic Potential of Lipocalin 2 in Cancer

Lipocalin-2 (LCN2) is a secreted glycoprotein linked to several physiological roles, including transporting hydrophobic ligands across cell membranes, modulating immune responses, maintaining iron homeostasis, and promoting epithelial cell differentiation. Although LNC2 is expressed at low levels in most human tissues, it is abundant in aggressive subtypes of cancer, including breast, pancreas, thyroid, ovarian, colon, and bile duct cancers. High levels of LCN2 have been associated with increased cell proliferation, angiogenesis, cell invasion, and metastasis. Moreover, LCN2 modulates the degradation, allosteric events, and enzymatic activity of matrix metalloprotease-9, a metalloprotease that promotes tumor cell invasion and metastasis. Hence, LCN2 has emerged as a potential therapeutic target against many cancer types. This review summarizes the most relevant findings regarding the expression, biological roles, and regulation of LCN2, as well as the proteins LCN2 interacts with in cancer. We also discuss the approaches to targeting LCN2 for cancer treatment that are currently under investigation, including the use of interference RNAs, antibodies, and gene editing.

Mid-trimester amniotic fluid proteome's association with spontaneous preterm delivery and gestational duration

BACKGROUND

Amniotic fluid is clinically accessible via amniocentesis and its protein composition may correspond to birth timing. Early changes in the amniotic fluid proteome could therefore be associated with the subsequent development of spontaneous preterm delivery.

OBJECTIVE

The main objective of this study was to perform unbiased proteomics analysis of the association between mid-trimester amniotic fluid proteome and spontaneous preterm delivery and gestational duration, respectively. A secondary objective was to validate and replicate the findings by enzyme-linked immunosorbent assay using a second independent cohort.

METHODS

Women undergoing a mid-trimester genetic amniocentesis at Sahlgrenska University Hospital/Östra between September 2008 and September 2011 were enrolled in this study, designed in three analytical stages; 1) an unbiased proteomic discovery phase using LC-MS analysis of 22 women with subsequent spontaneous preterm delivery (cases) and 37 women who delivered at term (controls), 2) a validation phase of proteins of interest identified in stage 1, and 3) a replication phase of the proteins that passed validation using a second independent cohort consisting of 20 cases and 40 matched controls.

RESULTS

Nine proteins were nominally significantly associated with both spontaneous preterm delivery and gestational duration, after adjustment for gestational age at sampling, but none of the proteins were significant after correction for multiple testing. Several of these proteins have previously been described as being associated with spontaneous PTD etiology and six of them were thus validated using enzyme linked immunosorbent assay. Two of the proteins passed validation; Neutrophil gelatinase-associated lipocalin and plasminogen activator inhibitor 1, but the results could not be replicated in a second cohort.

CONCLUSIONS

Neutrophil gelatinase-associated lipocalin and Plasminogen activator inhibitor 1 are potential biomarkers of spontaneous preterm delivery and gestational duration but the findings could not be replicated. The negative findings are supported by the fact that none of the nine proteins from the exploratory phase were significant after correction for multiple testing.

Biomarkers of Kidney Injury in Very-low-birth-weight Preterm Infants: Influence of Maternal and Neonatal Factors

BACKGROUND/AIM

Acute kidney injury is an important cause of mortality in very-low-birth-weight (VLBW) preterm infants. As in the general population, the detection of renal damage cannot rely on the measurement of serum creatinine, since it has been demonstrated to be a weak predictor and a delayed indicator of kidney function deterioration. However, several candidate biomarkers have failed to prove sufficient specificity and sensitivity for a routine clinical use because of the poor awareness of their biological role. This study was aimed to investigate the impact of different maternal and neonatal conditions on several renal biomarkers in VLBW preterm infants during the first week of life.

PATIENTS AND METHODS

Preterm infants<32 weeks' gestation and <1500g were enrolled. We measured urinary biomarkers kidney injury molecule 1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL), cystatin C, epidermal growth factor (EGF) and osteopontin (OPN) on the 1st, 3rd, and 7th day after birth.

RESULTS

Thirty-tree infants were included. The multivariate analysis showed a significant association between gestational age, the presence of patent ductus arteriosus, antenatal maternal hypertension and the levels of urinary biomarkers.

CONCLUSION

There is a possible relation between early biomarkers of renal injury and antenatal, perinatal and post-natal characteristics in VLBW preterm infants during the first week of life.

Fluid Biomarkers for Predicting the Prognosis of Liver Cirrhosis

Liver cirrhosis is the terminal stage of most chronic liver conditions, with a high risk of mortality. Careful evaluation of the prognosis of cirrhotic patients and providing precise management are crucial to reduce the risk of mortality. Although the liver biopsy and hepatic venous pressure gradient (HVPG) can efficiently evaluate the prognosis of cirrhotic patients, their application is limited due to the invasion procedures. Child-Pugh score and the model for end-stage liver disease (MELD) score had been widely used in the assessment of cirrhotic prognosis, but the defects of subjective variable application in Child-Pugh score and unsuitability to all phases of liver cirrhosis in MELD score limit their prognostic values. In recent years, continuous efforts have been made to investigate the prognostic value of body fluid biomarkers for cirrhotic patients, and promising results have been reported. Since the collection of fluid specimens is easy, noninvasive, and repeatable, fluid biomarkers can be ideal indicators to predict the prognosis of cirrhosis. Here, we reviewed noninvasive fluid biomarkers in different prognostic functions, including the prediction of survival and complication development.

Integration of transcriptomics, proteomics and metabolomics identifies biomarkers for pulmonary injury by polyhexamethylene guanidine phosphate (PHMG-p), a humidifier disinfectant, in rats

Polyhexamethylene guanidine phosphate (PHMG-p) was used as a humidifier disinfectant in Korea. PHMG induced severe pulmonary fibrosis in Koreans. The objective of this study was to elucidate mechanism of pulmonary toxicity caused by PHMG-p in rats using multi-omics analysis. Wistar rats were intratracheally instilled with PHMG-p by single (1.5 mg/kg) administration or 4-week (0.1 mg/kg, 2 times/week) repeated administration. Histopathologic examination was performed with hematoxylin and eosin staining. Alveolar macrophage aggregation and granulomatous inflammation were observed in rats treated with single dose of PHMG-p. Pulmonary fibrosis, chronic inflammation, bronchiol-alveolar fibrosis, and metaplasia of squamous cell were observed in repeated dose group. Next generation sequencing (NGS) was performed for transcriptome profiling after mRNA isolation from bronchiol-alveoli. Bronchiol-alveoli proteomic profiling was performed using an Orbitrap Q-exactive mass spectrometer. Serum and urinary metabolites were determined using 1H-NMR. Among 418 differentially expressed genes (DEGs) and 67 differentially expressed proteins (DEPs), changes of 16 mRNA levels were significantly correlated with changes of their protein levels in both single and repeated dose groups. Remarkable biological processes represented by both DEGs and DEPs were defense response, inflammatory response, response to stress, and immune response. Arginase 1 (Arg1) and lipocalin 2 (Lcn2) were identified to be major regulators for PHMG-p-induced pulmonary toxicity based on merged analysis using DEGs and DEPs. In metabolomics study, 52 metabolites (VIP > 0.5) were determined in serum and urine of single and repeated-dose groups. Glutamate and choline were selected as major metabolites. They were found to be major factors affecting inflammatory response in association with DEGs and DEPs. Arg1 and Lcn2 were suggested to be major gene and protein related to pulmonary damage by PHMG-p while serum or urinary glutamate and choline were endogenous metabolites related to pulmonary damage by PHMG-p.

Evaluation of serum neutrophil gelatinase-associated lipocalin in older patients with chronic kidney disease

OBJECTIVE

Chronic kidney disease (CKD) is a major health-care burden all over the world, and aging is an important risk factor for end-stage renal disease (ESRD). Neutrophil gelatinase-associated lipocalin (NGAL) has been confirmed as a novel marker for early diagnosis of acute kidney injury. Other studies have found that NGAL takes part in the mechanisms of CKD progression. The aim of this study was to evaluate the expression of serum NGAL in CKD, particularly in elderly patients who rapidly progressed to end-stage renal failure.

METHODS

Serum NGAL, cystatin C, creatinine, urea, and other factors were evaluated in a cohort of 160 CKD patients (mean age 75.29 ± 12.08 years) with various etiologies.

RESULTS

Serum NGAL was closely related to cystatin C, creatinine, urea, and estimated glomerular filtration rate (eGFR). Special correlations between NGAL and, respectively, anemia and hypoalbuminemia were also found. The cutoff value of NGAL was calculated from Stage 2 to Stage 5. Receiver-operator curve analysis showed good area under the curve (>0.8) and high sensitivity (> 70%) on the cutoff value of NGAL. The NGAL levels increased progressively with the increasing of 2- and 5-year risk of ESRD using the Kidney Failure Risk Equations (KFRE).

CONCLUSION

In elderly patients with CKD, serum NGAL reflects renal impairment and presents a strong and independent risk marker for progression of ESRD.

A Unique Conformational Distortion Mechanism Drives Lipocalin 2 Binding to Bacterial Siderophores

Lcn2 is a host defense protein induced via the innate immune response to sequester iron-loaded bacterial siderophores. However, excess or prolonged elevation of Lcn2 levels can induce adverse cellular effects, including oxidative stress and inflammation. In this work, we use Hydrogen-Deuterium eXchange (HDX) and Isothermal Titration Calorimetry (ITC) to characterize the binding interaction between Lcn2 and siderophores enterobactin and 2,3-DHBA, in the presence and absence of iron. Our results indicate a rare "Type II" interaction in which binding of siderophores drives the protein conformational equilibrium toward an unfolded state. Linking our molecular model to cellular assays, we demonstrate that this "distorted binding mode" facilitates a deleterious cellular accumulation of reactive oxygen species that could represent the molecular origin of Lcn2 pathology. These results add important insights into mechanisms of Lcn2 action and have implications in Lcn2-mediated effects including inflammation.

Lipocalin-2-The myth of its expression and function

Lipocalin-2 is a functional biomarker for acute and chronic kidney diseases, heart failure and obesity-related medical complications. It is rapidly induced in epithelial cells under stress conditions, but constitutively produced from pre-adipocytes and mature adipocytes. Measuring the lipocalin-2 levels represents an effective approach for risk prediction, patient stratification and disease management. Nevertheless, due to ligand-binding, post-translational modification and protein-protein interaction, lipocalin-2 exists as multiple variants that elicit different pathophysiological functions. To characterize the specific structure-functional relationships of lipocalin-2 variants is critical for the development of biomarker assays with sufficient precision and reliability. Moreover, identifying the pathological forms of lipocalin-2 will provide new therapeutic targets and treatment approaches for obesity-related complications.

Protective effect and mechanisms of exogenous neutrophil gelatinase-associated lipocalin on lipopolysaccharide-induced injury of renal tubular epithelial cell

PURPOSES

To investigate the protective effect of exogenous neutrophil gelatinase-associated lipocalin (NGAL) on the lipopolysaccharide-induced injury of renal tubular epithelial cells and its regulation of autophagy.

METHODS

Renal tubular epithelial cells were treated with lipopolysaccharide (LPS) at different concentrations (0-100 μg/mL) and at different times (0-24 h), the expression of NGAL was detected to determine the optimal time and concentration of LPS treatment. The NGAL gene knockdown lentivirus (NGAL-RNAi) was constructed and verified its knockdown rate and inhibition effect. Renal tubular epithelial cells were randomly divided into Control group, LPS group, LPS + NGAL group, NGAL-RNAi + LPS group, and NGAL-RNAi + LPS + NGAL group. Western blot and immunofluorescence tested the expression of autophagy-associated proteins, the changes in the number of autophagosomes were observed by electron microscopy, analyzed the role of exogenous NGAL.

RESULTS

The study showed the expression of autophagy-associated proteins (LC3-II and Beclin-1) in NGAL-RNAi + LPS group was significantly lower than the LPS group (P < 0.0100). The expression of LC3-II and Beclin-1 in the NGAL-RNAi + LPS + NGAL group was significantly higher than the NGAL-RNAi + LPS group (P < 0.0100). After the addition of exogenous NGAL, the autophagosomes in the LPS + NGAL group and the NGAL-RNAi + LPS + NGAL group were significantly increased under the electron microscope compared with the LPS group and the NGAL-RNAi + LPS group, and the cell proliferation rate and cell viability was significantly higher than unjoined groups (P < 0.0500).

CONCLUSION

NGAL knockdown can significantly reduce the level of autophagy and decrease the proliferation rate and viability of cells.The addition of exogenous NGAL can increase the level of autophagy. This suggests that NGAL may play a protective role in the LPS-induced injury of renal tubular epithelial cells by promoting autophagy.