Lcn2 Levels Research Articles

Association between Chronic Kidney Disease and Non-Alcoholic Fatty Liver Disease: A Cross Sectional Study

Abstract Background Nonalcoholic fatty liver disease (NAFLD) is a growing health problem that poses a significant burden as it is currently the most prevalent form of chronic liver disease, affecting an estimated 25% of the worldwide population. Aim of the Work to evaluate the role of plasma LCN2 levels in the diagnosis and prognosis of patients with non-alcoholic fatty liver disease. Patients and Methods Our case-control study was conducted on 102 Egyptian subjects between the ages of 18 and 70, recruited from the Internal Medicine and Hepatology Department and Clinics at Ain Shams University Hospital during the period from March 2023 to August 2023, and divided them into two groups. Group I: 51 Egyptian patients diagnosed with NAFLD (61% males; 39% females). Group II: 51 Egyptian healthy controls (51% males; 49% females) Results In this study, LCN2 levels were significantly higher in cases than in the control group (p < 0.001), with a mean of 1893.214 ±1002.852 in the cases and a mean of 466.020 ± 397.699 in the controls. This suggests the use of LCN2 as a possible diagnostic marker of NAFLD. The mean LCN2 levels in this study also significantly increased as the grade of fatty liver increased from I to III (p < 0.001). This in turn proposes the use of LCN2 as a prognostic marker for NAFLD progression. LCN2 also significantly correlated with the fatty liver index and NAFLD Fibrosis scoring systems, but not with Fib-4. It showed an excellent diagnostic performance in this study with an area under ROC of 0.906, an 84% sensitivity, a 90% specificity, 89.6% PPV and 85.2% NPV for the prediction of NAFLD patients. Conclusion Lipocalin-2 performs as a diagnostic marker for non-alcoholic liver disease, and a possible prognostic test that may be used to follow up the degree of steatosis. Other studies should be done on a larger size of participants to determine the prevalence of LCN2 in Egyptian population as well as other populations. Other studies should also be expanded to include NAFLD with degrees of fibrosis, and more quantitative imaging tools could be used to compare LCN2 levels with the NAFLD stage. The levels of LCN2 can be also measured in cohort studies before and after treatment of NAFLD to evaluate its sensitivity to the response of treatment.

Dynamic changes in the real-time glomerular filtration rate and kidney injury markers in different acute kidney injury models

In this study, we dynamically monitored the glomerular filtration rate and other assessment of renal function and markers of injury in various mice models of acute kidney injury. Male C57BL/6 mice were utilized to establish acute kidney injury models of sepsis, ischemia reperfusion, cisplatin, folic acid, aristolochic acid and antibiotic. In addition to the real time glomerular filtration rate, renal LCN-2 and HAVCR-1 mRNA expression levels, and serum creatinine, urea nitrogen and cystatin c levels were also used to evaluate renal function. In addition, the protein levels of LCN-2 and HAVCR-1 in renal, serum and urine were measured. Our results demonstrated that the changes in biomarkers always lagged the real time glomerular filtration rate during the progression and recovery of renal injury. Cystatin-c can reflect renal injury earlier than other markers, but it remains higher in the recovery stage. Perhaps the glomerular filtration rate does not reflect the greater injury caused by vancomycin plus piperacillin.

Lipocalin-2 as a marker of inflammation, bone density, and triglyceride-glucose index for new-onset arthritis patients in Mosul, Iraq.

Lipocalin-2 is an acute phase-associated adipokine that can serve as an inflammatory and biomarker indicator of cartilage deterioration in osteoarthritis. However, its role in the musculoskeletal system remains not fully understood. Hence, this study aimed to evaluate lipocalin-2 and its relationship with markers of inflammation (Interferon-gamma, ESR, and CRP), bone density (vitamin D3 and calcium), and the triglyceride-glucose index in new-onset arthritis patients in Mosul, Iraq. This study included 125 participants aged 20 to 65, divided into two groups. The Arthritis Patient Group comprised 70 participants (37 females and 33 males) attending the Bone Diseases Consultation Unit at the Ibn Sina Teaching Hospital in Mosul, Iraq. The Control Group comprised 31 females and 24 males. Ethical approval was obtained from the Iraqi Ministry of Health - Nineveh Health (No. 2022095). Commercial ELISA kits were used to measure serum lipocalin-2, Interferon-gamma, ESR, and CRP as inflammation markers, vitamin D3, and calcium as bone density markers. Moreover, the Triglyceride Glucose (TYG) Index was evaluated. The findings revealed a significant increase in lipocalin-2 levels in males compared to females, with LCN-2 increasing with age. Arthritis patients showed a significant increase (72%) in lipocalin-2 levels. Inflammatory indicators (erythrocyte sedimentation rate, C-reactive protein, interferon-gamma) displayed significant increases (46%, 1200%, and 581%, respectively). Glucose (23%), triglycerides (71%), and TYG index (21%) also exhibited significant increases. Meanwhile, bone density indicators (vitamin D3 and calcium) found a significant decrease (53% and 20%, respectively) in arthritis patients. Linear correlation coefficient (R) analysis revealed a significant positive relationship between lipocalin-2 and indicators of inflammation, glucose, TG, and TYG index. This study's findings suggest that LCN-2 serum levels were higher in patients with new-onset arthritis than in controls in Mosul, and LCN-2 serum increased in males compared with females and getting older serum LCN-2 increased for the patients and control groups. Furthermore, a significant correlation was found between the Triglyceride Glucose Index, which measures metabolic disorders, and serum LCN-2 levels and inflammatory indicators in new-onset arthritis patients in Mosul, Iraq.

Bioinformatics and experimental approach identify lipocalin 2 as a diagnostic and prognostic indicator for lung adenocarcinoma

Backgroundlipocalin 2 (LCN2) is a secreted glycoprotein that plays key roles in tumorigenesis and progression. Interestingly, LCN2 appears to have a contradictory function in developing lung adenocarcinoma (LUAD). Thus, we intend to explore the role of LCN2 in LUAD through bioinformatics and experimental validation. MethodsLCN2 expression of LUAD was investigated in the TCGA, TIMER and HPA databases. The relationship between LCN2 and prognosis was investigated by KM plotter, TCGA and GEO databases. GO, KEGG and protein-protein interactions network analysis were conducted to investigate the potential mechanism of LCN2. The relevance of LCN2 to cancer-immune infiltrates was investigated in the TCGA and TIMER databases. Quantitative reverse transcription PCR, western blot and enzyme-linked immunosorbent assay were performed to identify the expression level of LCN2 in cells and serum samples. The CCK-8, wound healing and transwell assay were used to confirm the effect of LCN2 on cell proliferation, migration and invasion in LUAD. The receiver operating characteristic curve was utilized to assess the diagnostic efficiency of LCN2 further. ResultsLCN2 expression was significantly upregulated in LUAD (P < 0.05), and was correlated with the clinical stage, tumor size, lymph node metastasis and distant metastasis (P < 0.05). There was a high correlation between high LCN2 and worse prognosis in LUAD. Functional network analysis suggested that LCN2 was associated with multiple signal pathways in cancers, such as JAK-STAT, TNF, NF-κB, HIF-1 and PI3K-Akt signal pathways. In addition, the knockdown of LCN2 significantly inhibited the ability of cell proliferation, migration and invasion. Immune infiltration analysis indicated that LCN2 is associated with multiple immune cell infiltration. Notably, LCN2 demonstrated high diagnostic efficiency for LUAD (AUC = 0.818, P < 0.05), especially for stage III-IV patients could reach 0.895. ConclusionsLCN2 as an oncogenic glycoprotein promotes the cancer progression related to immune infiltrates, which might be a potential diagnostic and prognostic marker in LUAD.

#1593 ARGDRR, a novel disintegrin, attenuates AKI to CKD-related renal fibrosis

Abstract Background and Aims Acute kidney injury (AKI) can lead to progress renal fibrosis, resulting in chronic kidney disease (CKD) and end stage renal disease (ESRD). Nevertheless, the underlying pathological mechanisms remain unclear. Platelet activation has been demonstrated as one of the important factors involved in the pathophysiology of AKI, and studies show the therapeutic potential for using platelet inhibitors or antagonists in ischemia-reperfusion (IR)-induced AKI models. However, drug-induced side effects, including thrombotic microangiopathies (TMA)-related kidney damage, thrombocytopenia and bleeding, hinder clinical application in AKI or CKD treatment. Our newly developed dual effect disintegrin, ARGDRR, is derived from snake venom exert a high affinity to αIIbβ3 and αvβ3 binding affinity without causing bleeding and other thrombosis-related side effects. Method We performed a unilateral ischemia-reperfusion injury (UIRI) model to investigate integrin αIIb(Itga2b) and β3(Itgb3) mRNA levels in the injured kidney for 15 days. For exploring the therapeutic efficiency of ARGDRR in AKI, we administered ARGDRR post-ischemic injury and measured platelet activation after 24 hours using quantitative polymerase chain reaction (qPCR) and immunohistochemistry (IHC) for Itgb3, Lcn2, and CD42b. For exploring the therapeutic efficiency of ARGDRR in CKD progression, we administrated ARGDRR daily for 15 days after IRI with nephrectomy, and examined the difference of renal dysfunction, renal fibrosis, and cell death compared to sham group. Results We found that platelet activation with progressively increased mRNA level of platelet glycoprotein IIb-GPIIIa (Itga2b and Itgb3) in the UIRI kidney over time. After 24 hr of ischemic AKI, ARGDRR administration reduced Lcn2 and Itgb3 mRNA level and CD42b positive area in the kidney, indicating its efficacy in protecting the kidneys by inhibiting platelet activation and aggregation. In AKI to CKD transition, serum creatine and blood urea nitrogen (BUN) were significantly lower both in efficacious and high dose of ARGDRR administration group. ARGDRR significantly reduced CD42b expression and increased LTL positive area. Also, ARGDRR administration alleviated renal fibrosis, cell apoptosis and senescence-related molecules p21 and Ctgf expression in the AKI to CKD transition. Conclusion Our results have successfully proved our hypothesis that disintegrin-ARGDRR has the potential for renal protection in the transition of AKI to CKD through inhibition of platelet activation and aggregation during acute injury.

Lipocalin-2 as a prognostic marker in patients with acute exacerbation of idiopathic pulmonary fibrosis

BackgroundLipocalin-2 (LCN2) is a secretory glycoprotein upregulated by oxidative stress; moreover, patients with idiopathic pulmonary fibrosis (IPF) have shown increased LCN2 levels in bronchoalveolar lavage fluid (BALF). This study aimed to determine whether circulatory LCN2 could be a systemic biomarker in patients with IPF and to investigate the role of LCN2 in a bleomycin-induced lung injury mouse model.MethodsWe measured serum LCN2 levels in 99 patients with stable IPF, 27 patients with acute exacerbation (AE) of IPF, 51 patients with chronic hypersensitivity pneumonitis, and 67 healthy controls. Further, LCN2 expression in lung tissue was evaluated in a bleomycin-induced lung injury mouse model, and the role of LCN2 was investigated using LCN2-knockout (LCN2 -/-) mice.ResultsSerum levels of LCN2 were significantly higher in patients with AE-IPF than in the other groups. The multivariate Cox proportional hazards model showed that elevated serum LCN2 level was an independent predictor of poor survival in patients with AE-IPF. In the bleomycin-induced lung injury mouse model, a higher dose of bleomycin resulted in higher LCN2 levels and shorter survival. Bleomycin-treated LCN2 -/- mice exhibited increased BALF cell and protein levels as well as hydroxyproline content. Moreover, compared with wild-type mice, LCN2-/- mice showed higher levels of circulatory 8-isoprostane as well as lower Nrf-2, GCLC, and NQO1 expression levels in lung tissue following bleomycin administration.ConclusionsOur findings demonstrate that serum LCN2 might be a potential prognostic marker of AE-IPF. Moreover, LCN2 expression levels may reflect the severity of lung injury, and LCN2 may be a protective factor against bleomycin-induced acute lung injury and oxidative stress.

Abstract 4482: Development of small molecule inhibitors of lipocalin 2 for the treatment of aggressive cancers

Abstract Lipocalin-2 (LCN2), a secreted protein pivotal in iron homeostasis, immune responses, siderophore transport, and epithelial cell differentiation. LCN2 is highly abundant in aggressive forms of many cancers including breast, pancreatic, ovarian, and esophageal cancer. Elevated LCN2 levels in aggressive tumors correlate with heightened cancer cell motility, proliferation, angiogenesis, invasion, and metastasis. After the protein folds it makes a barrel structure which encloses a three-calyx pocket that can bind and transport molecules. A first generation of small molecule inhibitors (SMIs) targeting LCN2 demonstrated efficacy in attenuating the proliferative capacity of Inflammatory breast cancer (IBC) cells. IBC stands as a rare and highly aggressive variant, accounting for 1 to 5% of all BC cases, with 20-30% presenting as de novo metastatic disease. In the previous studies the concentration of LCN2 inhibitors to reduce cell proliferation in 50% was around 10 µM. In pursuit of better LCN2 SMIs, we conducted in-silico analysis using a library of 369,000 ligands. Through the High-Performance Computer Facility at UPR Río Piedras, we employed AutoDock Vina for virtual screening, targeting the LCN2-calyx with Lys134 as the central coordinate. Docking protocols, predicting binding affinities, identified 8,162 out of 327,638 ligands that have been docked already with values below -9.6 kcal/mol for further consideration. The next phase involves subjecting these potential inhibitors to the SwissADME tool for a comprehensive evaluation of absorption, distribution, metabolism, and excretion parameters, as well as pharmacokinetics, drug-likeness, and medicinal chemistry considerations. The parameters to be evaluated are the Lipinski rules, which states that an orally active drug may have a maximum of one violation and the pann-assay interference compounds (PAINS) alerts tool, a source of false positives for biologically active compounds. The top candidates, exhibit binding affinities within the range of -11.5 to -12.2. After SwissADME filtering, we will re-rank the ligand list, identifying 30 commercially available candidates for subsequent cell viability assays in SUM149 (TNBC) and SUM190 (HER2+) cell lines. This multifaceted approach integrates computational methodologies with rigorous experimental validation, paving the way for potential therapeutic interventions in IBC treatment. Citation Format: Marienid Flores-Colón, Cristal A. Peña-Vázquez, Eliud Hernández-O'Farril, Luis E. Vázquez-Quiñones, Pablo E. Vivas-Mejía. Development of small molecule inhibitors of lipocalin 2 for the treatment of aggressive cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4482.

Neutrophil-Associated Proteins as Novel Biomarkers Elevated in Cerebrospinal Fluid of Patients With Neurosyphilis.

The immunopathological mechanisms underlying neurosyphilis remain incompletely elucidated, and the diagnosis of neurosyphilis presents challenges. We used an antibody microarray to detect 640 proteins in cerebrospinal fluid (CSF) samples collected from 6 patients with non-neurosyphilis and 10 with neurosyphilis. The levels of CSF CXCL1, CXCL8, G-CSF, LCN2, MMP8, and MMP9 in 46 patients with non-neurosyphilis, 51 with untreated neurosyphilis, and 31 posttreatment for neurosyphilis were quantified using enzyme-linked immunosorbent assay. The associations between the levels of these proteins and clinical parameters in neurosyphilis were evaluated using Spearman analysis, and the diagnostic performance of these proteins in neurosyphilis was assessed using receiver operating characteristic curve. A total of 102 differentially expressed proteins between neurosyphilis and non-neurosyphilis were identified. The levels of significantly elevated neutrophil-associated proteins (CXCL1, CXCL8, G-CSF, LCN2, MMP8, and MMP9) in neurosyphilis positively correlated with white blood cell counts, rapid plasma regain (RPR) titer, and protein concentration in CSF. The combination of CSF CXCL8, MMP9, and LCN2 yielded an area under the curve of 0.92 for diagnosing neurosyphilis, surpassing that of CSF RPR. CXCL1, CXCL8, G-CSF, LCN2, MMP8, and MMP9 could be associated with central nervous system damage of neurosyphilis. The combination of CSF CXCL8, MMP9, and LCN2 is a promising biomarker for diagnosing neurosyphilis.

Review of lipocalin-2-mediated effects in diabetic retinopathy.

Studies have uncovered LCN2 as a marker of inflammation strongly related to obesity, insulin resistance, and abnormal glucose metabolism in humans, and is involved in vascular diseases, inflammatory diseases, and neurological diseases. In recent years, studies have shown that elevated levels of LCN2 have a strong association with diabetic retinopathy (DR), but the pathogenesis is unknown. Here, we reviewed the relevant literature and compiled the pathogenesis associated with LCN2-induced DR. We searched PubMed and Web of Science electronic databases using "lipocalin-2, diabetic retinopathy, retinal degeneration, diabetic microangiopathies, diabetic neuropathy and inflammation" as subject terms. In diabetic retinal neuropathy, LCN2 causes impaired retinal photoreceptor function and retinal neurons; in retinal microangiopathy, LCN2 induces apoptosis of retinal vascular endothelial cells and promotes angiogenesis; in retinal inflammation, increased secretion of LCN2 recruits inflammatory cells and induces pro-inflammatory cytokines. Moreover, LCN2 has the potential as a biomarker for DR. Recent studies have shown that retinal damage can be attenuated by silencing LCN2, which may be associated with the inhibition of caspase-1-mediated pyroptosis, and LCN2 may be a new target for the treatment of DR. In conclusion, LCN2, involved in the development of diabetic retinopathy, is a key factor in diabetic retinal microangiopathy, neurodegeneration, and retinal inflammation. LCN2 is likely to be a novel molecular target leading to DR, and a more in-depth study of the pathogenesis of DR caused by LCN2 may provide considerable benefits for clinical research and potential drug development.

Serum Lipocalin-2 Levels as a Biomarker in Pre- and Post-Pubertal Klinefelter Syndrome Patients: A Pilot Study.

Klinefelter syndrome (KS) is a male genetic disease caused by the presence of an extra X chromosome, causing endocrine disorders mainly responsible for a high rate of infertility and metabolic disorders in adulthood. Scientific research is interested in identifying new biomarkers that can be predictive or prognostic of alterations strictly connected to KS. Lipocalin-2 (LCN-2, also known as NGAL) is a small protein initially identified within neutrophils as a protein related to innate immunity. Serum LCN-2 estimation seems to be a useful tool in predicting the metabolic complications caused by several pathological conditions. However, little is known about its potential role in infertility conditions. The present pilot study aims to investigate the presence of LCN-2 in the serum of a group of pre-pubertal and post-pubertal children affected by KS, compared to healthy controls. We demonstrated for the first time the presence of elevated levels of LCN-2 in the serum of KS patients, compared to controls. This increase was accompanied, in pre-pubertal KS patients, by the loss of correlation with LH and HDL, which instead was present in the healthy individuals. Moreover, in all KS individuals, a positive correlation between LCN-2 and inhibin B serum concentration was found. Despite the limited size of the sample analyzed, our preliminary data encourage further studies to confirm the findings and to extend the study to KS adult patients, to verify the predictive/prognostic value of LCN-2 as new biomarker for metabolic diseases and infertility associated with the pathology.

Increased plasma lipocalin‐2 levels are associated with nonmotor symptoms and neuroimaging features in patients with Parkinson's disease

AbstractLipocalin‐2 (LCN2) is essential for the regulation of neuroinflammation and cellular uptake of iron. This study aimed to evaluate plasma LCN2 levels and explore their correlation with clinical and neuroimaging features in Parkinson's disease (PD) patients. Enzyme‐linked immunosorbent assay (ELISA) was used to measure plasma LCN2 levels in 120 subjects. Evaluation of motor symptoms and nonmotor symptoms in PD patients was assessed by the associated scales. Voxel‐based morphometry (VBM) was used to evaluate brain volume alterations, and quantitative susceptibility mapping (QSM) was used to quantitatively analyze brain iron deposition in 46 PD patients. Plasma LCN2 levels were significantly higher in PD patients than those in healthy controls. LCN2 levels were negatively correlated with Montreal Cognitive Assessment (MoCA) scores, total brain gray matter volume (GMV), and GMV/total intracranial volume (TIV) ratio, but positively correlated with Hamilton Anxiety Rating Scale (HAMD) scores and mean QSM values of the bilateral substantial nigra (SN). Receiver operating characteristic (ROC) curves confirmed that plasma LCN2 levels had good predictive accuracy for PD. The results suggest that plasma LCN2 levels have potential as a biomarker for the diagnosis of PD. LCN2 may be a therapeutic target for neuroinflammation and brain iron deposition.

Evaluating the Effects of Chronic Oral Exposure to the Food Additive Silicon Dioxide on Oral Tolerance Induction and Food Sensitivities in Mice.

The increasing prevalence of food sensitivities has been attributed to changes in gut microenvironment; however, ubiquitous environmental triggers such as inorganic nanoparticles (NPs) used as food additives have not been thoroughly investigated. We explored the impact of the NP-structured food-grade silicon dioxide () on intestinal immune response involved in oral tolerance (OT) induction and evaluated the consequences of oral chronic exposure to this food-additive using a mouse model of OT to ovalbumin (OVA) and on gluten immunopathology in mice expressing the celiac disease risk gene, HLA-DQ8. Viability, proliferation, and cytokine production of mesenteric lymph node (MLN) cells were evaluated after exposure to . C57BL/6J mice and a mouse model of OT to OVA were orally exposed to or vehicle for 60 d. Fecal lipocalin-2 (Lcn-2), anti-OVA IgG, cytokine production, and immune cell populations were analyzed. Nonobese diabetic (NOD) mice expressing HLA-DQ8 (NOD/DQ8), exposed to or vehicle, were immunized with gluten and immunopathology was investigated. MLN cells exposed to presented less proliferative T cells and lower secretion of interleukin 10 (IL-10) and transforming growth factor beta () by T regulatory and cells compared to control, two factors mediating OT. Mice given exhibited intestinal Lcn-2 level and interferon gamma () secretion, showing inflammation and less production of IL-10 and . These effects were also observed in OVA-tolerized mice exposed to , in addition to a breakdown of OT and a lower intestinal frequency of T cells. In NOD/DQ8 mice immunized with gluten, the villus-to-crypt ratio was decreased while the intraepithelial lymphocyte counts and the Th1 inflammatory response were aggravated after treatment. Our results suggest that chronic oral exposure to blocked oral tolerance induction to OVA, and worsened gluten-induced immunopathology in NOD/DQ8 mice. The results should prompt investigation on the link between exposure and food sensitivities in humans. https://doi.org/10.1289/EHP12758.

P130 High serum lipocalin-2 expression at the diagnosis in children with ulcerative colitis: a pilot study

Abstract Background The identification of new biomarker is a main challenge in inflammatory boweldisease. Lipocalin-2 (LCN-2) is a pleiotropic mediator of various inflammatory processes. We determined the serum levels of LCN-2 in a cohort of newly diagnosed UC children, and we compared them with healthy controls. Methods Prospective cross-sectional observational study conducted at the Pediatric Gastroenterology, hepatology, and nutrition Unit of the Umberto I Hospital in Rome and at the IBBC – Institute of Biochemistry and Cell Biology – CNR in Rome. All children aged 6-18 years of age, newly diagnosed with UC at the Pediatric Gastroenterology and Liver Unit, Sapienza University of Rome, were consecutively enrolled. Blood withdrawal was conducted upon diagnosis. Human serum LCN-2 (Cat. No. DY1757) was measured using a sandwich enzyme-linked-immunosorbent assay (ELISA) kits (R&amp;D Systems, Minneapolis, MN, USA), according to the protocols provided by the manufacturer. Clinical, demographic, biochemical and endoscopic data were recorded. Results Thirty-two children with a new diagnosis of UC [11 (34%) female, mean age 12,7 ± 4] and 38 age- and sex-matched healthy control [21 (55%) females, mean age 11.71 ± 4] were consecutively enrolled. Serum LCN-2 levels were significantly higher in cases compared to controls (280 ± 152 ng/mL vs 66 ± 55 ng/mL), p &amp;lt; 0,001]. Among UC children, significantly higher LCN2 levels were measured in pancolitis (363.7± 155.2 ng/mL) compared to proctitis, left-sided and extensive colitis (184.9 ± 74.65 ng/mL; p = 0.0003). A significant inverse correlation was observed between LCN-2 and albumin levels at the diagnosis by the Spearman coefficient correlation (r = −0.455; P = 0.03) and a significant direct correlation was observed between LCN-2 and CRP values at the diagnosis (r = 0.44; p &amp;lt;0.05). Conclusion Serum LCN-2 levels are significantly higher in children with UC compared to the healthy control group, with the highest levels observed in children with the most extensive disease. Such results as well as and its correlation with the actual disease monitoring tool, make this protein an interesting candidate biomarker.

Lipocalin-2 Serum Levels in Rheumatoid Arthritis Patients Treated with Adalimumab and Its Correlation with Proinflammatory Factors.

Obesity is associated with an increased risk for different chronic diseases such as osteoarthritis (OA) or rheumatoid arthritis (RA). In fact, adipose tissue is now recognized as an endocrine organ able to secrete a wide variety of factors called adipokines, which have been demonstrated to participate in the pathophysiology of RA by regulating inflammation and immunity. LCN2 is one of these adipose tissue-derived factors. However, scarce information is available about the levels of this adipokine in different rheumatic diseases. Therefore, we aimed to analyze LCN2 serum levels in healthy, OA, and RA patients under different treatments. Serum levels of LCN2, among other proinflammatory and chemotactic factors, have been measured by ELISA or Multiplex in the following four groups of individuals: healthy, OA, and RA patients treated with conventional treatment or adalimumab. We found increased serum levels of LCN2 in OA and RA patients. Interestingly, LCN2 serum levels show a similar pattern to that observed for different proinflammatory and chemotactic factors, being increased in RA conventional treated patients in comparison to RA patients treated with adalimumab. Also, RA patients under conventional treatment revealed a positive and significant correlation between LCN2 and CCL2, CCL3, IL-8, IL-1β, IL-6, and CRP. In patients with RA treated with adalimumab, only IL-6 and CRP correlated significantly with LCN2. Our results clearly suggest that LCN2 is modulated and associated with inflammation in rheumatic diseases. Therefore, the serum levels of this adipokine might be used as an additional biomarker of the inflammatory/disease activity.

Nicotine suppresses crystalline silica-induced astrocyte activation and neuronal death by inhibiting NF-κB in the mouse hippocampus.

Exposure to crystalline silica (CS) in occupational settings induces chronic inflammation in the respiratory system and, potentially, the brain. Some workers are frequently concurrently exposed to both CS and nicotine. Here, we explored the impact of nicotine on CS-induced neuroinflammation in the mouse hippocampus. In this study, we established double-exposed models of CS and nicotine in C57BL/6 mice. To assess depression-like behavior, experiments were conducted at 3, 6, and 9 weeks. Serum inflammatory factors were analyzed by ELISA. Hippocampus was collected for RNA sequencing analysis and examining the gene expression patterns linked to inflammation and cell death. Microglia and astrocyte activation and hippocampal neuronal death were assessed using immunohistochemistry and immunofluorescence staining. Western blotting was used to analyze the NF-κB expression level. Mice exposed to CS for 3 weeks showed signs of depression. This was accompanied by elevated IL-6 in blood, destruction of the blood-brain barrier, and activation of astrocytes caused by an increased NF-κB expression in the CA1 area of the hippocampus. The elevated levels of astrocyte-derived Lcn2 and upregulated genes related to inflammation led to higher neuronal mortality. Moreover, nicotine mitigated the NF-κB expression, astrocyte activation, and neuronal death, thereby ameliorating the associated symptoms. Silica exposure induces neuroinflammation and neuronal death in the mouse hippocampal CA1 region and depressive behavior. However, nicotine inhibits CS-induced neuroinflammation and neuronal apoptosis, alleviating depressive-like behaviors in mice.

Abstract 003: Aberrant Host Immune Responses Specific To Microbial-derived Ligands Are Linked To Hypertension In BPH/2J Mice

It has been established that derangements in host-microbiota homeostasis leads to hypertension. However, the precise mechanisms remain largely unknown. Microbial-derived ligands released into the host circulation are sensed and eliminated by various host innate and adaptive immune mechanisms. Herein, we focused on such microbial-derived ligands and hypothesized that defect in host innate and adaptive immune response to counter microbial-derived ligands is linked to hypertension. To test this hypothesis, both in vitro and in vivo studies were conducted. First, bone marrow-derived macrophages from Blood Pressure Normal (BPN/3J, systolic blood pressure: 113.2±2.20 mm Hg) and Blood Pressure Hypertensive (BPH/2J, systolic blood pressure: 143.9±4.10 mm Hg) mice (male, 8 weeks) were challenged with various Toll-like receptor (TLR) ligands of microbial origin. Unstimulated macrophages from BPH mice displayed reduced levels of the co-stimulatory activation markers CD40, CD80 and CD86 (~2 fold) compared to macrophages from BPN/3J mice. Such differences, however, was normalized upon stimulation with ligands for TLR3 (poly-I:C), TLR4 (LPS), TLR5 (flagellin), TLR7/8 (R848) and TLR9 (CpG-DNA). Despite so, BPH-macrophages displayed blunted IL-6 and lipocalin-2 (~2 fold) levels in response to all the aforementioned TLR ligands when compared to macrophages from BPN mice. To confirm these findings in vivo , we challenged BPN and BPH mice with the microbial-derived ligand, flagellin. Interestingly, even though BPH mice had reduced cytokine responses to flagellin as monitored by levels of Lcn2 (BPN 320.9 ± 22.20 vs BPH 230.8 ± 12.40, p&lt;0.05) and CXCL1 (BPN 40.9 ± 4.6 vs BPH 23.8 ± 2.4, p&lt;0.05), they displayed higher levels of flagellin-specific IgG (BPN vs BPH O.D 450 , 0.51 ± 0.10 vs 0.93 ± 0.07, p&lt;0.05) and substantially lower levels of flagellin-specific IgA (BPN vs BPH O.D 450 , 0.44 ± 0.13 v s 0.13 ± 0.03, p&lt;0.05). Collectively, both in vitro and in vivo studies demonstrate that both innate and adaptive immune responses specifically against microbial ligands is substantially deranged in the hypertensive state.

Lipocalin 2 induces self-limited inhibition of osteoblast differentiation of mesenchymal stem cells

To explore the role of lipocalin 2 (Lcn2) in bone development and senile osteoporosis. Chromatin immunoprecipitation with H3K27AC and H3K9Me3 antibodies coupled with massively parallel sequencing (ChIP-Seq) was performed to analyze the changes in binding of modified histones at the Lcn2 gene locus in C3H10T1/2 mesenchymal stem cells (MSCs) induced with osteogenic induction medium for 3 days. ITRAQ-MS/MS and ELISA were used to compare Lcn2 protein expressions in the cancellous bone and the serum between 16- and 3-month-old male mice. The effect of treatment with recombinant Lcn2 protein on osteogenic differentiation of C3H10T1/2 cells was evaluated by detecting changes in ALP expression, and Western blotting was performed to examine the changes in OSX and OCN expression. The expression of Lcn2 protein in the cancellous bone and its serum levels were significantly higher in 16-month-old than in 3-month-old male mice (P < 0.01). In C3H10T1/2 cells, ALP expression level decreased significantly after treatment with recombinant Lcn2 protein (P < 0.05) accompanied by lowered protein expressions of OSX and OCN (P < 0.05). Analysis with ROSE software revealed a super enhancer in the Lcn2 gene region of C3H10T1/2 cells after osteogenesis induction. RNA-seq results confirmed that Lcn2 was among the top 4 up-regulated genes in C3H10T1/2 cells following osteogenic induction, and a super enhancer was also detected in Zbtb16 gene, which showed the highest up- regulation after osteogenic induction. Real- time quantitative PCR further confirmed that the mRNA level of Lcn2 increased sharply in C3H10T1/2 cells after osteogenic induction (P < 0.001). Lcn2 is essential for normal osteogenic differentiation of MSCs, but its overexpression and excessive secretion in aging induce self-limited inhibition of osteogenic differentiation of MSCs.

Osteoblast-derived extracellular vesicles exert osteoblastic and tumor-suppressive functions via SERPINA3 and LCN2 in prostate cancer.

Clinically, the osteolytic phenotype is rare in prostate cancer (PCa), and the prognosis is generally worse than that of the osteoblastic phenotype. Osteoblastic prostate cancer (BPCa) is a major type of bone metastasis. Several factors responsible for osteogenesis have been identified, but the molecular mechanism of osteoblastic bone metastasis in PCa is not fully understood. Here, we show the osteogenic and tumor-suppressive roles of SERPINA3 and LCN2 in BPCa. In a co-culture of osteoblasts (OBs) and BPCa cells, SERPINA3 and LCN2 were remarkably upregulated in BPCa via OB-derived extracellular vesicles (EVs), while they were not in the co-culture of OBs and osteolytic prostate cancer (LPCa) cells. In both the co-culture system and mouse xenograft experiments with intracaudal injection, enhanced expression of SERPINA3 and LCN2 in PCa led to osteogenesis. Additionally, the addition of SERPINA3 and LCN2 to BPCa cells significantly suppressed the proliferative potential. Retrospective analysis also confirmed that high expression levels of SERPINA3 and LCN2 were significantly correlated with a better prognosis. Our results may partially explain how osteoblastic bone metastasis develops and why the prognosis for BPCa is relatively better than that for LPCa.

Spontaneous episodic inflammation in the intestines of mice lacking HNF4A is driven by microbiota and associated with early life microbiota alterations.

The inflammatory bowel diseases (IBD) occur in genetically susceptible individuals who mount inappropriate immune responses to their microbiota leading to chronic intestinal inflammation. Whereas IBD clinical presentation is well described, how interactions between microbiota and host genotype impact early subclinical stages of the disease remains unclear. The transcription factor hepatocyte nuclear factor 4 alpha (HNF4A) has been associated with human IBD, and deletion of Hnf4a in intestinal epithelial cells (IECs) in mice (Hnf4aΔIEC) leads to spontaneous colonic inflammation by 6-12 mo of age. Here, we tested if pathology in Hnf4aΔIEC mice begins earlier in life and if microbiota contribute to that process. Longitudinal analysis revealed that Hnf4aΔIEC mice reared in specific pathogen-free (SPF) conditions develop episodic elevated fecal lipocalin 2 (Lcn2) and loose stools beginning by 4-5 wk of age. Lifetime cumulative Lcn2 levels correlated with histopathological features of colitis at 12 mo. Antibiotic and gnotobiotic tests showed that these phenotypes in Hnf4aΔIEC mice were dependent on microbiota. Fecal 16S rRNA gene sequencing in SPF Hnf4aΔIEC and control mice disclosed that genotype significantly contributed to differences in microbiota composition by 12 mo, and longitudinal analysis of the Hnf4aΔIEC mice with the highest lifetime cumulative Lcn2 revealed that microbial community differences emerged early in life when elevated fecal Lcn2 was first detected. These microbiota differences included enrichment of a novel phylogroup of Akkermansia muciniphila in Hnf4aΔIEC mice. We conclude that HNF4A functions in IEC to shape composition of the gut microbiota and protect against episodic inflammation induced by microbiota throughout the lifespan. IMPORTANCE The inflammatory bowel diseases (IBD), characterized by chronic inflammation of the intestine, affect millions of people around the world. Although significant advances have been made in the clinical management of IBD, the early subclinical stages of IBD are not well defined and are difficult to study in humans. This work explores the subclinical stages of disease in mice lacking the IBD-associated transcription factor HNF4A in the intestinal epithelium. Whereas these mice do not develop overt disease until late in adulthood, we find that they display episodic intestinal inflammation, loose stools, and microbiota changes beginning in very early life stages. Using germ-free and antibiotic-treatment experiments, we reveal that intestinal inflammation in these mice was dependent on the presence of microbiota. These results suggest that interactions between host genotype and microbiota can drive early subclinical pathologies that precede the overt onset of IBD and describe a mouse model to explore those important processes.

Nerve growth factor receptor (Ngfr) induces neurogenic plasticity by suppressing reactive astroglial Lcn2/Slc22a17 signaling in Alzheimer’s disease

Neurogenesis, crucial for brain resilience, is reduced in Alzheimer’s disease (AD) that induces astroglial reactivity at the expense of the pro-neurogenic potential, and restoring neurogenesis could counteract neurodegenerative pathology. However, the molecular mechanisms promoting pro-neurogenic astroglial fate despite AD pathology are unknown. In this study, we used APP/PS1dE9 mouse model and induced Nerve growth factor receptor (Ngfr) expression in the hippocampus. Ngfr, which promotes neurogenic fate of astroglia during the amyloid pathology-induced neuroregeneration in zebrafish brain, stimulated proliferative and neurogenic outcomes. Histological analyses of the changes in proliferation and neurogenesis, single-cell transcriptomics, spatial proteomics, and functional knockdown studies showed that the induced expression of Ngfr reduced the reactive astrocyte marker Lipocalin-2 (Lcn2), which we found was sufficient to reduce neurogenesis in astroglia. Anti-neurogenic effects of Lcn2 was mediated by Slc22a17, blockage of which recapitulated the pro-neurogenicity by Ngfr. Long-term Ngfr expression reduced amyloid plaques and Tau phosphorylation. Postmortem human AD hippocampi and 3D human astroglial cultures showed elevated LCN2 levels correlate with reactive gliosis and reduced neurogenesis. Comparing transcriptional changes in mouse, zebrafish, and human AD brains for cell intrinsic differential gene expression and weighted gene co-expression networks revealed common altered downstream effectors of NGFR signaling, such as PFKP, which can enhance proliferation and neurogenesis in vitro when blocked. Our study suggests that the reactive non-neurogenic astroglia in AD can be coaxed to a pro-neurogenic fate and AD pathology can be alleviated with Ngfr. We suggest that enhancing pro-neurogenic astroglial fate may have therapeutic ramifications in AD.