GDF15 and LCN2 for early detection and prognosis of pancreatic cancer.

BACKGROUND: The prognosis of pancreatic ductal adenocarcinomas (PDAC) remains very poor, emphasizing the critical importance of early detection, where biomarkers offer unique potential. Although growth differentiation factor 15 (GDF15) and Lipocalin 2 (LCN2) have been linked to PDAC, their precise roles as biomarkers are uncertain. METHODS: Circulating levels of GDF15 and LCN2 were examined in human PDAC patients, heathy controls, and individuals with benign pancreatic diseases. Circulating levels of IL-6, CA19-9, and neutrophil-to-lymphocyte ratio (NLR) were measured for comparisons. Correlations between PDAC progression and overall survival were assessed. A mouse PDAC model was employed for comprehensive analyses, complementing the human studies by exploring associations with various metabolic and inflammatory parameters. Sensitivity and specificity of the biomarkers were evaluated. FINDINGS: Our results demonstrated elevated levels of circulating GDF15 and LCN2 in PDAC patients compared to both healthy controls and individuals with benign pancreatic diseases, with higher GDF15 levels associated with disease progression and increased mortality. In PDAC mice, circulating GDF15 and LCN2 progressively increased, correlating with tumor growth, behavioral manifestations, tissue and molecular pathology, and cachexia development. GDF15 exhibited highly sensitive and specific for PDAC patients compared to CA19-9, IL-6, or NLR, while LCN2 showed even greater sensitivity and specificity in PDAC mice. Combining GDF15 and LCN2, or GDF15 and CA19-9, enhanced sensitivity and specificity. INTERPRETATION: Our findings indicate that GDF15 holds promise as a biomarker for early detection and prognosis of PDAC, while LCN2 could strengthen diagnostic panels.

Myricanol represses renal fibrosis by activating TFAM and ZNRF1 to inhibit tubular epithelial cells ferroptosis.

BACKGROUND: Mitochondrial dysfunction induces ferroptosis in renal tubular epithelial cells (TECs). Studies have shown that myricanol maintains muscle cell function by enhancing mitochondrial energy metabolism. HYPOTHESIS: Myricanol delays renal fibrosis by maintaining mitochondrial integrity and inhibiting ferroptosis in TECs. METHODS: Mice kidney lacking mitochondrial transcription factor A (TFAM), blood specimens, or pathological sections of renal tissue from patients with renal failure were used to explore the relationship between mitochondrial and renal functions. Erastin induced-TECs ferroptosis was used to study the potential mechanism by which TFAM regulates renal fibrosis. Chronic kidney disease (CKD) mice were utilized to explore the anti-fibrotic effects of myricanol. RESULTS: The number of mitochondria and TFAM expression were decreased in human blood samples and pathological sections. Renal TFAM-deficient mice exhibited abnormalities in renal function, including ferroptosis and fibrosis. Ferrostatin-1 significantly inhibited renal fibrosis by preventing TECs ferroptosis. Transcriptional sequencing results indicated that zinc and ring finger 1 (ZNRF1) were important downstream genes of TFAM that regulate ferroptosis. We demonstrated that TFAM deficiency and ferroptosis, which destroyed interaction between ZNRF1 and the iron transport-related protein lipocalin-2 (LCN2), but myricanol clould reverse this effect. Overexpression of ZNRF1 efficiently maintained mitochondrial integrity and inhibited renal fibrosis. Myricanol ameliorated transforming growth factor ß1-induced mitochondrial impairment. We firstly confirmed that myricanol efficiently improved renal function and suppresses fibrosis in CKD mice. CONCLUSIONS: Myricanol efficiently inhibit fibrosis through activating TFAM to stimulate the interaction between ZNRF1 and LCN2.

Effects of fructan and gluten on gut microbiota in individuals with self-reported non-celiac gluten/wheat sensitivity-a randomised controlled crossover trial.

BACKGROUND: Individuals with non-celiac gluten/wheat sensitivity (NCGWS) experience improvement in gastrointestinal symptoms following a gluten-free diet. Although previous results have indicated that fructo-oligosaccharides (FOS), a type of short-chain fructans, were more likely to induce symptoms than gluten in self-reported NCGWS patients, the underlying mechanisms are unresolved. METHODS: Our main objective was therefore to investigate whether FOS-fructans and gluten affect the composition and diversity of the faecal microbiota (16S rRNA gene sequencing), faecal metabolites of microbial fermentation (short-chain fatty acids [SCFA]; gas chromatography with flame ionization detector), and a faecal biomarker of gut inflammation (neutrophil gelatinase-associated lipocalin, also known as lipocalin 2, NGAL/LCN2; ELISA). In the randomised double-blind placebo-controlled crossover study, 59 participants with self-reported NCGWS underwent three different 7-day diet challenges with gluten (5.7 g/day), FOS-fructans (2.1 g/day), and placebo separately (three periods, six challenge sequences). RESULTS: The relative abundances of certain bacterial taxa were affected differently by the diet challenges. After the FOS-fructan challenge, Fusicatenibacter increased, while Eubacterium (E.) coprostanoligenes group, Anaerotruncus, and unknown Ruminococcaceae genera decreased. The gluten challenge was primarily characterized by increased abundance of Eubacterium xylanophilum group. However, no differences were found for bacterial diversity (α-diversity), overall bacterial community structure (ß-diversity), faecal metabolites (SCFA), or NGAL/LCN2. Furthermore, gastrointestinal symptoms in response to FOS-fructans were generally not linked to substantial shifts in the gut bacterial community. However, the reduction in E. coprostanoligenes group following the FOS-fructan challenge was associated with increased gastrointestinal pain. Finally, correlation analysis revealed that changes in gastrointestinal symptoms following the FOS-fructan and gluten challenges were linked to varying bacterial abundances at baseline. CONCLUSIONS: In conclusion, while FOS-fructans induced more gastrointestinal symptoms than gluten in the NCGWS patients, we did not find that substantial shifts in the composition nor function of the faecal microbiota could explain these differences in the current study. However, our results indicate that individual variations in baseline bacterial composition/function may influence the gastrointestinal symptom response to both FOS-fructans and gluten. Additionally, the change in E. coprostanoligenes group, which was associated with increased symptoms, implies that attention should be given to these bacteria in future trials investigating the impact of dietary treatments on gastrointestinal symptoms. TRIAL REGISTRATION: Clinicaltrials.gov as NCT02464150.

Baicalein ameliorates chronic itch in ACD mice by suppressing the spinal astrocytic STAT3-LCN2 cascade.

Chronic itch is a maladaptive and debilitating symptom in patients with allergic contact dermatitis (ACD), adversely affecting their quality of life. There is a lack of effective treatments for ACD-associated uncontrollable itch. In this study, we explored the antipruritic effects of baicalein (BE), a bioactive flavonoid extracted from the root of Scutellaria baicalensis Georgi, and the underlying mechanisms in alleviating chronic itch triggered by diphenylcyclopropenone (DCP) in a mouse model of ACD. The ACD mice were intraperitoneally injected with BE (5, 30, and 60 mg·kg-1·d-1) for 7 days during the DCP challenge phase. The results showed that DCP-treated mice exhibited severe spontaneous scratching behaviors that was reduced after BE injections in a dose-dependent manner accompanied by inhibition of spinal astrocyte activation. We observed that the spinal astrocytic STAT3-LCN2 cascade plays a crucial role in controlling the activation of astrocytes in chronic itch. Intrathecal injection of the STAT3 inhibitor AG490 or Lcn2 siRNA significantly reduced scratching behavior and astrocyte activation in ACD mice. Moreover, BE markedly attenuated the increased phosphorylation of STAT3 (p-STAT3) and LCN2 expression in the spinal cords of ACD mice and in lipopolysaccharide-stimulated primary spinal astrocytes. Altogether, BE relieved chronic itch by suppressing the spinal astrocytic STAT3-LCN2 cascade. These findings provide a potential avenue for the management of chronic itch. Schematic summary of the main findings illustrating that BE alleviates chronic itch through suppressing the spinal astrocytic STAT3-LCN2 cascade. Specifically, BE suppresses the expression of p-STAT3 to inhibit the reactive state of astrocytes in spinal dorsal horn, and then decreases the expression of astrocytic LCN2 to alleviate chronic itch in ACD mice.

Sleep loss-induced oncogenic pathways are mediated via the neuron-specific interleukin-1 receptor accessory protein (AcPb).

Interleukin-1ß (IL1), a pleiotropic cytokine, is involved in sleep regulation, tumor ontogeny, and immune responses. IL1 receptor adaptor proteins, including the IL1 receptor accessory protein (AcP), and its neuron-specific isoform, AcPb, are required for IL1 signaling. The AcPb isoform is resultant from alternate splicing of the AcP transcript. Our previous studies using AcPb null (AcPb-/-) mice characterized its participation in sleep regulation and emergent neuronal/glial network properties. Here, we investigated the impact of acute sleep disruption (SD) on brain cancer-related pathways in wild-type (WT) and AcPb-/- mice, employing RNA sequencing methods. In WT mice, SD increased AcPb mRNA levels, but not AcP mRNA, confirming prior similar work in rats. Transcriptome and pathway enrichment analyses demonstrated significant alterations in cancer, immune, and viral disease-related pathways in WT mice after SD, which were attenuated in AcPb-/- mice including multiple upregulated Src phosphorylation-signaling-dependent genes associated with cancer progression and metastasis. Our RNAseq findings, were analyzed within the context of The Cancer Genome Atlas Program (TCGA) data base; revealing an upregulation of sleep- and cancer-linked genes (e.g., IL-17B, IL-17RA, LCN2) across various tumors, including brain tumors, compared to normal tissues. Sleep-linked factors, identified through TCGA analyses, significantly impact patient prognosis and survival, particularly in low-grade glioma (LGG) and glioblastoma multiforme (GBM) patients. Overall, our findings suggest that SD promotes a pro-tumor environment through AcPb-modulated pathways.

Computational Insights into Captopril's Inhibitory Potential Against MMP9 and LCN2 in Bladder Cancer: Implications for Therapeutic Application.

Objectives: Captopril is a commonly used therapeutic agent in the management of renovascular hypertension (high blood pressure), congestive heart failure, left ventricular dysfunction following myocardial infarction, and nephropathy. Captopril has been found to interact with proteins that are significantly associated with bladder cancer (BLCA), suggesting that it could be a potential medication for BLCA patients with concurrent hypertension. Methods: DrugBank 5.0 was utilized to identify the direct protein targets (DPTs) of captopril. STRING was used to analyze the multiple protein interactions. TNMPlot was used for comparing gene expression in normal, tumor, and metastatic tissue. Then, docking with target proteins was done using Autodock. Molecular dynamics simulations were applied for estimate the diffusion coefficients and mean-square displacements in materials. Results: Among all these proteins, MMP9 is observed to be an overexpressed gene in BLCA and its increased expression is linked to reduced survival in patients. Our findings indicate that captopril effectively inhibits both the wild type and common mutated forms of MMP9 in BLCA. Furthermore, the LCN2 gene, which is also overexpressed in BLCA, interacts with captopril-associated proteins. The overexpression of LCN2 is similarly associated with reduced survival in BLCA. Through molecular docking analysis, we have identified specific amino acid residues (Tyr179, Pro421, Tyr423, and Lys603) at the active pocket of MMP9, as well as Tyr78, Tyr106, Phe145, Lys147, and Lys156 at the active pocket of LCN2, with which captopril interacts. Thus, our data provide compelling evidence for the inhibitory potential of captopril against human proteins MMP9 and LCN2, both of which play crucial roles in BLCA. Conclusion: These discoveries present promising prospects for conducting subsequent validation studies both in vitro and in vivo, with the aim of assessing the suitability of captopril for treating BLCA patients, irrespective of their hypertension status, who exhibit elevated levels of MMP9 and LCN2 expression.

Unraveling the molecular complexity: Wtap/Ythdf1 and Lcn2 in novel traumatic brain injury secondary injury mechanisms.

The primary aim of this research was to explore the functions of Wtap and Ythdf1 in regulating neuronal Lipocalin-2 (Lcn2) through m6A modification in traumatic brain injury (TBI). By employing transcriptome sequencing and enrichment analysis, we identified the Wtap/Ythdf1-mediated Lcn2 m6A modification pathway as crucial in TBI. In our in vitro experiments using primary cortical neurons, knockout of Wtap and Ythdf1 led to the inhibition of Lcn2 m6A modification, resulting in reduced neuronal death and inflammation. Furthermore, overexpression of Lcn2 in cortical neurons induced the activation of reactive astrocytes and M1-like microglial cells, causing neuronal apoptosis. In vivo experiments confirmed the activation of reactive astrocytes and microglial cells in TBI and importantly demonstrated that Wtap knockdown improved neuroinflammation and functional impairment. These findings underscore the significance of Wtap/Ythdf1-mediated Lcn2 regulation in TBI secondary injury and suggest potential therapeutic implications for combating TBI-induced neuroinflammation and neuronal damage.

Astrocyte-derived lipocalin 2 promotes inflammation and scarring after spinal cord injury by activating SMAD in mice.

BACKGROUND: The inflammatory response and scar formation after spinal cord injury (SCI) limit nerve regeneration and functional recovery. Our research group has previously shown that the expression of astrocyte-derived lipocalin 2 (Lcn2) is upregulated after SCI, which correlates with neuronal apoptosis and functional recovery. Therefore, we speculate that astrocyte-specific knockdown of Lcn2 after SCI may lead to a better prognosis. METHODS: Tissue RNA sequencing, Western blotting, PCR, and immunofluorescence assays were conducted to assess the expression of Lcn2 following SCI in mice. Adeno-associated virus 9 (AAV9) transfection was employed to specifically reduce the expression of Lcn2 in astrocytes, and subsequent evaluations of scarring and inflammation were conducted. In vitro experiments involved treating primary astrocytes with TGF-ß or an A1-induced mixture (C1q, TNF-α and IL-1α) following Lcn2 knockdown. Finally, the intrathecal injection of recombinant Lcn2 (ReLcn2) protein was conducted post-injury to further confirm the role of Lcn2 and its underlying mechanism in SCI. RESULTS: Lcn2 expression was elevated in astrocytes after SCI at 7 dpi (days post injury). Lcn2 knockdown in astrocytes is beneficial for neuronal survival and functional recovery after SCI, and is accompanied by a reduced inflammatory response and inhibited scar formation. The inhibition of SMAD-associated signaling activation was identified as a possible mechanism, and in vitro experiments further confirmed this finding. ReLcn2 further activated SMAD-associated signaling and aggravated motor function after SCI. CONCLUSION: The upregulation of Lcn2 expression in astrocytes is involved in neuroinflammation and scar formation after SCI, and the activation of SMAD-associated signaling is one of the underlying mechanisms.

Gandouling Regulates Ferroptosis and Improves Neuroinflammation in Wilson's Disease Through the LCN2/NLRP3 Signaling Pathway.

Purpose: Neuroinflammation is a main cause of neurological damage in Wilson's disease (WD). Ferroptosis is present in the WD pathological process, which is also closely related to the neuroinflammation. LCN2, a ferroptosis-related gene in WD, is linked with the activation of NLRP3 inflammasome. Our group has previously demonstrated that Gandouling (GDL) can effectively improve neuroinflammation in WD. This study aims to investigate the protective effect of GDL on neuroinflammation in animal and cell models of WD, and whether the pharmacological mechanism is related to the LCN2/NLRP3 signaling pathway. Methods: Toxic milk (TX) mice and HT22 cells stimulated by copper ions were selected as models. The pathology of hippocampal tissues in TX mice were observed by HE staining and transmission electron microscopy. High-throughput sequencing analysis was conducted to screen ferroptosis-related genes in WD. The expression of LCN2 and GPX4 in hippocampus of TX mice were detected by immunohistochemical. The expression of LCN2, NLRP3, GPX4, and SLC7A11 was determined in TX mice and HT22 cells by Western blotting and RT-qPCR. The levels of Fe2+, inflammatory factor indicators TNF-α, IL-1ß and IL-6 and oxidative stress indicators 4-HNE, MAD, SOD, GSH and ROS were detected in each group by ELISA. Results: The results showed that GDL ameliorated pathological and mitochondrial damages in hippocampus of TX mice. The analysis of bioinformatics showed that LCN2 was a differential gene associated with ferroptosis in WD. The results of Western blotting and RT-qPCR indicated that GDL reduced the expression of LCN2 and NLRP3, and enhanced the expression of GPX4 and SLC711 in TX mice and HT22 cells. The ELISA results showed that GDL decreased the expression of Fe2+ and inflammatory factors TNF-α, IL-1ß and IL-6 in TX mice with ferroptosis inducer intervention and copper ion-loaded HT22 cells. GDL decreased the expression of oxidative stress indicators ROS, 4-HNE and MDA, and increased the expression of oxidative stress indicators GSH and SOD in TX mice and copper ion-loaded HT22 cells. Conclusion: GDL has anti-inflammatory and antioxidant effects. LCN2 is a differential gene associated with ferroptosis in WD. GDL may alleviate ferroptosis by inhibiting the LCN2/NLPR3 signaling pathway, thereby improving neuroinflammatory responses and exerting neuroprotective effects in WD.

The role of LCN2 in exacerbating ferroptosis levels in acute ischemic stroke injury.

Due to the complex pathogenesis of acute ischemic stroke (AIS), further investigation into its underlying mechanisms is necessary. Presently, existing literature indicates a close association between ferroptosis and AIS injury; however, the precise mechanism and molecular target of ferroptosis in AIS injury remain elusive. By RNA sequencing, we found a significant increase in LCN2 expression in the ischemic cortex. In order to investigate the potential role of LCN2 in modulating AIS injury through the regulation of ferroptosis, we utilized RNA interference (RNAi) knockdown and gene overexpression experiments. The findings from experiments conducted both in vitro and in vivo revealed a marked increase in ferroptosis levels within the AIS model group. Suppression of the LCN2 gene resulted in a significant reduction in ferroptosis levels in OGD/R cells. Conversely, upregulation of LCN2 exacerbated ferroptosis levels in OGD/R cells. The results suggest that elevated levels of ferroptosis may result from heightened expression of LCN2, thereby exacerbating ischemia/reperfusion injury. This study indicates the involvement of ferroptosis in the pathogenesis of AIS and highlights LCN2 as a regulator of ferroptosis in AIS-induced injury, suggesting a potential therapeutic target for ischemic stroke.

LCN2 regulates the gut microbiota and metabolic profile in mice infected with Mycobacterium bovis.

Infection with Mycobacterium bovis precipitates a spectrum of pathologies in bovines, notably necrotic pneumonia, mastitis, and arthritis, impinging upon the health and nutritional assimilation of these animals. A pivotal factor, lipocalin 2 (Lcn2), is responsive to microbial invasion, inflammatory processes, and tissue damage, the extent of which Lcn2 modulates the gut environment, however, remains unclear in response to M. bovis-induced alterations. To explore the role of Lcn2 in shaping the gut milieu of mice during a 5-week period post-M. bovis infection, Lcn2 knockout Lcn2-/- mice were scrutinized for changes in the gut microbiota and metabolomic profiles. Results showed that Lcn2-/- mice infected with M. bovis exhibited notable shifts in the operational taxonomic units (OTUs) of gut microbiota, alongside significant disparities in α and ß diversity. Concomitantly, a marked increase was observed during the 5-week period in the abundance of Akkermansia, Oscillospira, and Bacteroides, coupled with a substantial decrease in Ruminococcus within the microbiome of Lcn2 knockout mice. Notably, Akkermansia muciniphila was significantly enriched in the gut flora of Lcn2-/- mice. Furthermore, the absence of Lcn2 significantly altered the gut metabolomic landscape, evidenced by elevated levels of metabolites such as taurodeoxycholic acid, 10-undecenoic acid, azelaic acid, and dodecanedioic acid in Lcn2-/- mice. Our findings demonstrated that the lack of Lcn2 in the context of M. bovis infection profoundly affected the regulation of gut microbiota and metabolomic components, culminating in a transformed gut environment. Our results revealed that Lcn2 may regulate gut microbiota and metabolome components, changing the intestinal environment, thereby affecting the infection status of M. bovis. IMPORTANCE: Our study addresses the critical knowledge gap regarding the specific influence of lipocalin 2 (LCN2) in the context of Mycobacterium bovis infection, particularly focusing on its role in the gut environment. Utilizing LCN2 knockout (Lcn2-/-) mice, we meticulously assessed changes in the gut microbiota and metabolic components following M. bovis infection. Our findings reveal alterations in the gut microbial community, emphasizing the potentially crucial role of LCN2 in maintaining stability. Furthermore, we observed significant shifts in specific microbial communities, including the enrichment of Akkermansia muciniphila, known for its positive impact on intestinal health and immune regulation. The implications of our study extend beyond understanding the dynamics of the gut microbiome, offering insights into the potential therapeutic strategies for gut-related health conditions and microbial dysbiosis.

Astrocyte-secreted lipocalin-2 elicits bioenergetic failure-induced neuronal death that is causally related to high fatality in a mouse model of hepatic encephalopathy.

Hepatic encephalopathy (HE) is a neurological complication arising from acute liver failure with poor prognosis and high mortality; the underlying cellular mechanisms are still wanting. We previously found that neuronal death caused by mitochondrial dysfunction in rostral ventrolateral medulla (RVLM), which leads to baroreflex dysregulation, is related to high fatality in an animal model of HE. Lipocalin-2 (Lcn2) is a secreted glycoprotein mainly released by astrocytes in the brain. We noted the presence of Lcn2 receptor (Lcn2R) in RVLM neurons and a parallel increase of Lcn2 gene in astrocytes purified from RVLM during experimental HE. Therefore, our guiding hypothesis is that Lcn2 secreted by reactive astrocytes in RVLM may underpin high fatality during HE by eliciting bioenergetic failure-induced neuronal death in this neural substrate. In this study, we first established the role of astrocyte-secreted Lcn2 in a liver toxin model of HE induced by azoxymethane (100 µg/g, ip) in C57BL/6 mice, followed by mechanistic studies in primary astrocyte and neuron cultures prepared from postnatal day 1 mouse pups. In animal study, immunoneutralization of Lcn2 reduced apoptotic cell death in RVLM, reversed defunct baroreflex-mediated vasomotor tone and prolonged survival during experimental HE. In our primary cell culture experiments, Lcn2 produced by cultured astrocytes and released into the astrocyte-conditioned medium significantly reduced cell viability of cultured neurons. Recombinant Lcn2 protein reduced cell viability, mitochondrial ATP (mitoATP) production, and pyruvate dehydrogenase (PDH) activity but enhanced the expression of pyruvate dehydrogenase kinase (PDK) 1, PDK3 and phospho-PDHA1 (inactive PDH) through MAPK/ERK pathway in cultured neurons, with all cellular actions reversed by Lcn2R knockdown. Our results suggest that astrocyte-secreted Lcn2 upregulates PDKs through MAPK/ERK pathway, which leads to reduced PDH activity and mitoATP production; the reinforced neuronal death in RVLM is causally related to baroreflex dysregulation that underlies high fatality associated with HE.

Aquaporin-4 deletion leads to reduced infarct volume and increased peri-infarct astrocyte reactivity in a mouse model of cortical stroke.

Aquaporin-4 (AQP4) is the main water channel in brain and is enriched in perivascular astrocyte processes abutting brain microvessels. There is a rich literature on the role of AQP4 in experimental stroke. While its role in oedema formation following middle cerebral artery occlusion (MCAO) has been studied extensively, its specific impact on infarct volume remains unclear. This study investigated the effects of total and partial AQP4 deletion on infarct volume in mice subjected to distal medial cerebral artery (dMCAO) occlusion. Compared to MCAO, this model induces smaller infarcts confined to neocortex, and less oedema. We show that AQP4 deletion significantly reduced infarct volume as assessed 1 week after dMCAO, suggesting that the role of AQP4 in stroke goes beyond its effect on oedema formation and dissolution. The reduction in infarct volume was associated with increased astrocyte reactivity in the peri-infarct areas. No significant differences were observed in the number of microglia among the genotypes. These findings provide new insights in the role of AQP4 in ischaemic injury indicating that AQP4 affects both infarct volume and astrocyte reactivity in the peri-infarct zone. KEY POINTS: Aquaporin-4 (AQP4) is the main water channel in brain and is enriched in perivascular astrocyte processes abutting microvessels. A rich literature exists on the role of AQP4 in oedema formation following middle cerebral artery occlusion (MCAO). We investigated the effects of total and partial AQP4 deletion on infarct volume in mice subjected to distal medial cerebral artery occlusion (dMCAO), a model inducing smaller infarcts confined to neocortex and less oedema compared to MCAO. AQP4 deletion significantly reduced infarct volume 1 week after dMCAO, suggesting a broader role for AQP4 in stroke beyond oedema formation. The reduction in infarct volume was associated with increased astrocyte reactivity in the peri-infarct areas, while no significant differences were observed in the number of microglia among the genotypes. These findings provide new insights into the role of AQP4 in stroke, indicating that AQP4 affects both infarct volume and astrocyte reactivity in the peri-infarct zone.

Intestinal mRNA expression profiles associated with mucosal healing in ustekinumab-treated Crohn's disease patients: bioinformatics analysis and prospective cohort validation.

BACKGROUND: Variations exist in the response of patients with Crohn's disease (CD) to ustekinumab (UST) treatment, but the underlying cause remains unknown. Our objective was to investigate the involvement of immune cells and identify potential biomarkers that could predict the response to interleukin (IL) 12/23 inhibitors in patients with CD. METHODS: The GSE207022 dataset, which consisted of 54 non-responders and 9 responders to UST in a CD cohort, was analyzed. Differentially expressed genes (DEGs) were identified and subjected to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. Least absolute shrinkage and selection operator (LASSO) regression was used to screen the most powerful hub genes. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the predictive performances of these genes. Single-sample Gene Set Enrichment Analysis (ssGSEA) was used to estimate the proportions of immune cell types. These significantly altered genes were subjected to cluster analysis into immune cell-related infiltration. To validate the reliability of the candidates, patients prescribed UST as a first-line biologic in a prospective cohort were included as an independent validation dataset. RESULTS: A total of 99 DEGs were identified in the integrated dataset. GO and KEGG analyses revealed significant enrichment of immune response pathways in patients with CD. Thirteen genes (SOCS3, CD55, KDM5D, IGFBP5, LCN2, SLC15A1, XPNPEP2, HLA-DQA2, HMGCS2, DDX3Y, ITGB2, CDKN2B and HLA-DQA1), which were primarily associated with the response versus nonresponse patients, were identified and included in the LASSO analysis. These genes accurately predicted treatment response, with an area under the curve (AUC) of 0.938. T helper cell type 1 (Th1) cell polarization was comparatively strong in nonresponse individuals. Positive connections were observed between Th1 cells and the LCN2 and KDM5D genes. Furthermore, we employed an independent validation dataset and early experimental verification to validate the LCN2 and KDM5D genes as effective predictive markers. CONCLUSIONS: Th1 cell polarization is an important cause of nonresponse to UST therapy in patients with CD. LCN2 and KDM5D can be used as predictive markers to effectively identify nonresponse patients. TRIAL REGISTRATION: Trial registration number: NCT05542459; Date of registration: 2022-09-14; URL: https://www. CLINICALTRIALS: gov .

Characterization of cells expressing lipocalin-2 (LCN2) as a reporter.

Lipocalin-2 (LCN2), an effector molecule of the innate immune system that is small enough to be tagged as a reporter molecule, can be coupled with the ferric ion through a siderophore such as enterobactin (Ent). Mintbody (modification-specific intracellular antibody) can track a posttranslational protein modification in epigenetics. We constructed plasmids expressing the LCN2 hybrid of mintbody to examine the potential of LCN2 as a novel reporter for magnetic resonance imaging (MRI). Cells expressing the LCN2 hybrid of mintbody showed proper expression and localization of the hybrid and responded reasonably to Ent, suggesting their potential for in vivo study by MRI.

M1 macrophage-derived exosomes promote intervertebral disc degeneration by enhancing nucleus pulposus cell senescence through LCN2/NF-κB signaling axis.

Intervertebral disc degeneration (IVDD) is the primary factor contributing to low back pain (LBP). Unlike elderly patients, many young IVDD patients usually have a history of trauma or long-term abnormal stress, which may lead to local inflammatory reaction causing by immune cells, and ultimately accelerates degeneration. Research has shown the significance of M1-type macrophages in IVDD; nevertheless, the precise mechanism and the route by which it influences the function of nucleus pulposus cell (NPC) remain unknown. Utilizing a rat acupuncture IVDD model and an NPC degeneration model induced by lipopolysaccharide (LPS), we investigated the function of M1 macrophage-derived exosomes (M1-Exos) in IVDD both in vivo and in vitro in this study. We found that M1-Exos enhanced LPS-induced NPC senescence, increased the number of SA-ß-gal-positive cells, blocked the cell cycle, and promoted the activation of P21 and P53. M1-Exos derived from supernatant pretreated with the exosome inhibitor GW4869 reversed this result in vivo and in vitro. RNA-seq showed that Lipocalin2 (LCN2) was enriched in M1-Exos and targeted the NF-κB pathway. The quantity of SA-ß-gal-positive cells was significantly reduced with the inhibition of LCN2, and the expression of P21 and P53 in NPCs was decreased. The same results were obtained in the acupuncture-induced IVDD model. In addition, inhibition of LCN2 promotes the expression of type II collagen (Col-2) and inhibits the expression of matrix metalloproteinase 13 (MMP13), thereby restoring the equilibrium of metabolism inside the extracellular matrix (ECM) in vitro and in vivo. In addition, the NF-κB pathway is crucial for regulating M1-Exo-mediated NPC senescence. After the addition of M1-Exos to LPS-treated NPCs, p-p65 activity was significantly activated, while si-LCN2 treatment significantly inhibited p-p65 activity. Therefore, this paper demonstrates that M1 macrophage-derived exosomes have the ability to deliver LCN2, which activates the NF-κB signaling pathway, and exacerbates IVDD by accelerating NPC senescence. This may shed new light on the mechanism of IVDD and bring a fresh approach to IVDD therapy.

Structure, Functions, and Implications of Selected Lipocalins in Human Disease.

The lipocalin proteins are a large family of small extracellular proteins that demonstrate significant heterogeneity in sequence similarity and have highly conserved crystal structures. They have a variety of functions, including acting as carrier proteins, transporting retinol, participating in olfaction, and synthesizing prostaglandins. Importantly, they also play a critical role in human diseases, including cancer. Additionally, they are involved in regulating cellular homeostasis and immune response and dispensing various compounds. This comprehensive review provides information on the lipocalin family, including their structure, functions, and implications in various diseases. It focuses on selective important human lipocalin proteins, such as lipocalin 2 (LCN2), retinol binding protein 4 (RBP4), prostaglandin D2 synthase (PTGDS), and α1-microglobulin (A1M).

Berberine alleviates neuroinflammation by downregulating NFκB/LCN2 pathway in sepsis-associated encephalopathy: network pharmacology, bioinformatics, and experimental validation.

BACKGROUND: Sepsis refers to a systemic inflammatory response caused by infection, involving multiple organs. Sepsis-associated encephalopathy (SAE), as one of the most common complications in patients with severe sepsis, refers to the diffuse brain dysfunction caused by sepsis without central nervous system infection. However, there is no clear diagnostic criteria and lack of specific diagnostic markers. METHODS: The main active ingredients of coptidis rhizoma(CR) were identified from TCMSP and SwissADME databases. SwissTargetPrediction and PharmMapper databases were used to obtain targets of CR. OMIM, DisGeNET and Genecards databases were used to explore targets of SAE. Limma differential analysis was used to identify the differential expressed genes(DEGs) in GSE167610 and GSE198861 datasets. WGCNA was used to identify feature module. GO and KEGG enrichment analysis were performed using Metascape, DAVID and STRING databases. The PPI network was constructed by STRING database and analyzed by Cytoscape software. AutoDock and PyMOL software were used for molecular docking and visualization. Cecal ligation and puncture(CLP) was used to construct a mouse model of SAE, and the core targets were verified in vivo experiments. RESULTS: 277 common targets were identified by taking the intersection of 4730 targets related to SAE and 509 targets of 9 main active ingredients of CR. 52 common DEGs were mined from GSE167610 and GSE198861 datasets. Among the 25,864 DEGs in GSE198861, LCN2 showed the most significant difference (logFC = 6.9). GO and KEGG enrichment analysis showed that these 52 DEGs were closely related to "inflammatory response" and "innate immunity". A network containing 38 genes was obtained by PPI analysis, among which LCN2 ranked the first in Degree value. Molecular docking results showed that berberine had a well binding affinity with LCN2. Animal experiments results showed that berberine could inhibit the high expression of LCN2,S100A9 and TGM2 induced by CLP in the hippocampus of mice, as well as the high expression of inflammatory factors (TNFα, IL-6 and IL-1ß). In addition, berberine might reduce inflammation and neuronal cell death by partially inhibiting NFκB/LCN2 pathway in the hippocampus of CLP models, thereby alleviating SAE. CONCLUSION: Overall, Berberine may exert anti-inflammatory effects through multi-ingredients, multi-targets and multi-pathways to partially rescue neuronal death and alleviate SAE.

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 ß-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.

Engeletin alleviates depressive-like behaviours by modulating microglial polarization via the LCN2/CXCL10 signalling pathway.

Microglial polarization and associated inflammatory activity are the key mediators of depression pathogenesis. The natural Smilax glabra rhizomilax derivative engeletin has been reported to exhibit robust anti-inflammatory activity, but no studies to date have examined the mechanisms through which it can treat depressive symptoms. We showed that treatment for 21 days with engeletin significantly alleviated depressive-like behaviours in chronic stress social defeat stress (CSDS) model mice. T1-weighted imaging (T1WI), T2-weighted imaging (T2WI) imaging revealed no significant differences between groups, but the bilateral prefrontal cortex of CSDS mice exhibited significant increases in apparent diffusion coefficient and T2 values relative to normal control mice, with a corresponding reduction in fractional anisotropy, while engeletin reversed all of these changes. CSDS resulted in higher levels of IL-1ß, IL-6, and TNF-a production, enhanced microglial activation, and greater M1 polarization with a concomitant decrease in M2 polarization in the mPFC, whereas engeletin treatment effectively abrogated these CSDS-related pathological changes. Engeletin was further found to suppress the LCN2/C-X-C motif chemokine ligand 10 (CXCL10) signalling axis such that adeno-associated virus-induced LCN2 overexpression ablated the antidepressant effects of engeletin and reversed its beneficial effects on the M1/M2 polarization of microglia. In conclusion, engeletin can alleviate CSDS-induced depressive-like behaviours by regulating the LCN2/CXCL10 pathway and thereby altering the polarization of microglia. These data suggest that the antidepressant effects of engeletin are correlated with the polarization of microglia, highlighting a potential avenue for future design of antidepressant strategies that specifically target the microglia.