Increased Lipocalin-2 Contributes to the Pathogenesis of Psoriasis by Modulating Neutrophil Chemotaxis and Cytokine Secretion

TRPV3 promotes sebocyte inflammation via transcriptional modulating TLR2 in acne

Acne is a common chronic inflammatory disease of the pilosebaceous unit. Transient receptor potential vanilloid 3 (TRPV3) is an ion channel that is involved in inflammatory dermatosis development. However, the involvement of TRPV3 in acne-related inflammation remains unclear. Here, we used acne-like mice and human sebocytes to examine the role of TRPV3 in the development of acne. We found that TRPV3 expression increased in the skin lesions of Propionibacterium acnes (P. acnes)-injected acne-like mice and the facial sebaceous glands (SGs) of acne patients. TRPV3 promoted inflammatory cytokines and chemokines secretion in human sebocytes and led to neutrophil infiltration surrounding the SGs in acne lesions, further exacerbating sebaceous inflammation and participating in acne development. Mechanistically, TRPV3 enhanced TLR2 level by promoting transcriptional factor phosphorylated-FOS-like antigen-1 (p-FOSL1) expression and its binding to the TLR2 promoter, leading to TLR2 upregulation and downstream NF-κB signaling activation. Genetic or pharmacological inhibition of TRPV3 both alleviated acne-like skin inflammation in mice via the TLR2-NF-κB axis. Thus, our study revealed the critical role of TRPV3 in sebaceous inflammation and indicated its potential as an acne therapeutic target.

CXCL12+ dermal fibroblasts promote neutrophil recruitment and host defense by recognition of IL-17

The skin provides an essential barrier for host defense through rapid action of multiple resident and recruited cell types, but the complex communication network governing these processes is incompletely understood. To define these cell-cell interactions more clearly, we performed an unbiased network analysis of mouse skin during invasive S. aureus infection and revealed a dominant role for CXCL12+ fibroblast subsets in neutrophil communication. These subsets predominantly reside in the reticular dermis, express adipocyte lineage markers, detect IL-17 and TNFα, and promote robust neutrophil recruitment through NFKBIZ-dependent release of CXCR2 ligands and CXCL12. Targeted deletion of Il17ra in mouse fibroblasts resulted in greatly reduced neutrophil recruitment and increased infection by S. aureus. Analogous human CXCL12+ fibroblast subsets abundantly express neutrophil chemotactic factors in psoriatic skin that are subsequently decreased upon therapeutic targeting of IL-17. These findings show that CXCL12+ dermal immune acting fibroblast subsets play a critical role in cutaneous neutrophil recruitment and host defense.

Emerging Role of the IL-36/IL-36R Axis in Multiple Inflammatory Skin Diseases

IL-36 is a most recent member of the IL-1 cytokine family, primarily expressed at barrier sites of the body such as the skin, lungs, and intestine. It plays a vital role in inflammation and is implicated in the development of various cutaneous; intestinal; and pulmonary disorders, including psoriasis, inflammatory bowel disease, and chronic obstructive pulmonary disease. IL-36 comprises 4 isoforms: the proinflammatory IL-36α, IL-36β, and IL-36γ and the anti-inflammatory IL-36R antagonist. An imbalance between proinflammatory and anti-inflammatory IL-36 isoforms can contribute to the inflammatory fate of cells and tissues. IL-36 cytokines signal through an IL-36R heterodimer mediating their function through canonical signaling cacade, including the NF-B pathway. Prominent for its role in psoriasis, IL-36 has recently been associated with disease mechanisms in atopic dermatitis, hidradenitis suppurativa, neutrophilic dermatoses, autoimmune blistering disease, and Netherton syndrome. The major cutaneous source of IL-36 cytokines is keratinocytes, pointing to its role in the communication between the epidermis, innate (neutrophils, dendritic cells) immune system, and adaptive (T helper [Th]1 cells, Th17) immune system. Thus, cutaneous IL-36 signaling is crucial for the immunopathological outcome of various skin diseases. Consequently, the IL-36/IL-36R axis has recently been recognized as a promising drug target for the treatment of inflammatory disorders beyond psoriasis. This review summarizes the current update on IL-36 cytokines in inflammatory skin diseases.

Impact of Blood-Count-Derived Inflammatory Markers in Psoriatic Disease Progression

Psoriasis is a chronic immune-mediated disease, linked to local and systemic inflammation and predisposing patients to a higher risk of associated comorbidities. Cytokine levels are not widely available for disease progression monitoring due to high costs. Validated low-cost and reliable markers are needed for assessing disease progression and outcome. This study aims to assess the reliability of blood-count-derived inflammatory markers as disease predictors and to identify prognostic factors for disease severity. Patients fulfilling the inclusion criteria were enrolled in this study. Patients were divided into three study groups according to disease severity measured by the Body Surface Area (BSA) score: mild, moderate, and severe psoriasis. White blood cell count (WBC), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), derived neutrophil-to-lymphocyte ratio (d-NLR), systemic immune index (SII), systemic inflammation response index (SIRI), and aggregate index of systemic inflammation (AISI) positively were correlated with disease severity (p < 0.005). d-NLR, NLR, and SII are independent prognostic factors for mild and moderate psoriasis (p < 0.05). d-NLR is the only independent prognostic factor for all three study groups. Moderate psoriasis is defined by d-NLR values between 1.49 and 2.19. NLR, PLR, d-NLR, MLR, SII, SIRI, and AISI are useful indicators of systemic inflammation and disease severity in psoriasis.

Treatment-related changes in serum neutrophil gelatinase-associated lipocalin (NGAL) in psoriatic arthritis: results from the PIPA cohort study

OBJECTIVES

Obesity and psoriatic arthritis (PsA) have a complicated relationship. While weight alone does not cause PsA, it is suspected to cause worse symptoms. Neutrophil gelatinase-associated lipocalin (NGAL) is secreted through various cell types. Our objective was to assess the changes and trajectories in serum NGAL and clinical outcomes in patients with PsA during 12 months of anti-inflammatory treatment.

METHOD

This exploratory prospective cohort study enrolled PsA patients initiating conventional synthetic or biological disease-modifying anti-rheumatic drugs (csDMARDs/bDMARDs). Clinical, biomarker, and patient-reported outcome measures were retrieved at baseline, and 4 and 12 months. Control groups at baseline were psoriasis (PsO) patients and apparently healthy controls. The serum NGAL concentration was quantified by a high-performance singleplex immunoassay.

RESULTS

In total, 117 PsA patients started a csDMARD or bDMARD, and were compared indirectly at baseline with a cross-sectional sample of 20 PsO patients and 20 healthy controls. The trajectory in NGAL related to anti-inflammatory treatment for all included PsA patients showed an overall change of -11% from baseline to 12 months. Trajectories in NGAL for patients with PsA, divided into treatment groups, showed no clear trend in clinically significant decrease or increase following anti-inflammatory treatment. NGAL concentrations in the PsA group at baseline corresponded to the levels in the control groups. No correlation was found between changes in NGAL and changes in PsA outcomes.

CONCLUSION

Based on these results, serum NGAL does not add any value as a biomarker in patients with peripheral PsA, either for disease activity or for monitoring.

Role of Lipocalin-2 in N1/N2 Neutrophil Polarization After Stroke

BACKGROUND

Neutrophils and Lipocalin-2 (LCN2) play pivotal roles in cerebral ischemiareperfusion (I/R) injury. However, their contribution is not fully clarified.

OBJECTIVE

This study aimed to explore the role of LCN2 and its association with neutrophil polarization in I/R injury.

METHODS

A mouse model of middle cerebral artery occlusion (MCAO) was used to induce cerebral ischemia. LCN2mAb was administered 1 h and Anti-Ly6G was administered for 3d before MCAO. The role of LCN2 in the polarity transition of neutrophils was explored using an in vitro HL-60 cell model.

RESULTS

LCN2mAb pretreatment had neuroprotective effects in mice. The expression of Ly6G was not significantly different, but the expression of N2 neutrophils was increased. In the in vitro study, LCN2mAb-treated N1-HL-60 cells induced N2-HL-60 polarization.

CONCLUSION

LCN2 may affect the prognosis of ischemic stroke by mediating neutrophil polarization.

Lipocalin-2 promotes neutrophilic inflammation in nasal polyps and its value as biomarker

BACKGROUND

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a common chronic inflammatory disease of the nasal cavity and paranasal sinuses. The role of neutrophils in the pathogenesis of CRSwNP has attracted more attention in recent years, due to its association with more severe disease and reduced steroid responsiveness. Lipocalin-2 (LCN2) has been found to modulate neutrophils infiltration in other neutrophilic inflammation including inflammatory bowel disease, rheumatoid arthritis, and psoriasis. The aim was to evaluate the expression and regulator role of LCN2 in neutrophilic inflammation in CRSwNP, and its role as a potential biomarker predicting non-eosinophilic CRSwNP (neCRSwNP).

METHODS

Bioinformatic analysis, immunostainings, real-time PCR and ELISA were used to analyze the expression and location of LCN2 in nasal tissues. The expression of proinflammatory mediators were assessed in nasal tissues and secretions. LCN2 production in human nasal epithelial cells (HNECs) and neutrophils, as well as its role in neutrophilic inflammation was evaluated by in vitro experiments.

RESULTS

LCN2 was mainly located in neutrophils and HNECs of nasal polyps. LCN2 expression was also significantly higher in the polyp tissue and nasal secretions from patients with neCRSwNP. The LCN2 levels were positively correlated with type 3 inflammation markers, including G-CSF, IL-8, and IL-17. LCN2 expression could be upregulated by IL-17 A and TNF-α in HNECs, and LCN2 could also promote the expression of IL-8 in dispersed polyp cells and HNECs.

CONCLUSIONS

LCN2 could serve as a novel biomarker predicting patients with neCRSwNP, and the increased expression of LCN2 may participate in the pathogenesis of neCRSwNP.

Exosomal microRNA-223 from neutrophil-like cells inhibits osteogenic differentiation of PDLSCs through the cGMP-PKG signaling pathway

BACKGROUND AND OBJECTIVE

Neutrophils-derived exosomes have been shown to cause tissue inflammation in many diseases, but their role in periodontitis, a neutrophil-mediated disease, is unknown. Here, we investigated the effect of neutrophil-like cells derived exosomes on osteogenic dysfunction of periodontal ligament stem cells (PDLSCs) in periodontitis.

METHODS

Neutrophil-like cells were derived from HL-60 cells by dimethylsulfoxide stimulation. Exosomes were isolated by ultracentrifugation and characterized using transmission electron microscopy, nanoflow cytometry and western blot. MicroRNA-223 (miR-223) expression were analyzed by real-time PCR. Western blot, alkaline phosphatase (ALP), and alizarin red staining were conducted to assess whether exosomes could affect the osteogenic differentiation of PDLSCs. The expression of miR-223 was inhibited in PDLSCs by transfecting with miR-223 inhibitor. Cyclic guanosine monophosphate (cGMP) expression was determined by enzyme-linked immunosorbent assay.

RESULTS

We found that miR-223 was significantly increased in neutrophils and neutrophil-like cells derived exosomes. Treatment with exosomes derived from neutrophil-like cells upregulated miR-223 expression and inhibited the osteogenic differentiation of PDLSCs, while transfection with miR-223 inhibitor significantly promoted PDLSCs osteogenic differentiation. In addition, co-treatment with KT5823, a cGMP-PKG pathway inhibitor, markedly abrogated the rescue effects of miR-223 inhibitor on the osteogenic differentiation of PDLSCs.

CONCLUSIONS

Our findings suggest that neutrophil-like cells derived exosomes might inhibit osteogenic differentiation of PDLSCs by transporting miR-223 and regulating the cGMP-PKG signaling pathway.

Serum and Tissue Lipocalin-2 Expression in Chronic Kidney Disease Pruritic Patients

BACKGROUND

Uremic pruritus is an irritating symptom for patients with end-stage kidney disease. Lipocalin-2 (LCN2) has relevant importance in several biological cellular processes and immunity. It is also a major player in the progression of many disorders, such as renal injury.

AIM

To evaluate LCN2 expression in chronic kidney disease (CKD) pruritic patients in serum together with immunohistochemical expression in skin samples and further correlation of their results with the studied clinicopathologic parameters.

MATERIALS AND METHODS

Serum level of LCN2 (assessed by enzyme-linked immunosorbent assay) and skin immunohistochemical expression were investigated in 25 CKD patients and 25 healthy controls. Ten patients were subjected to narrowband ultraviolet B phototherapy for 12 weeks then re-evaluated for serum and tissue LCN2 after therapy.

RESULTS

LCN2 expression was increased significantly in both the epidermis and dermal adnexa in CKD patients over controls. Also, serum LCN2 level was higher in patients than in healthy subjects and was significantly associated with itching severity, grades of CKD, urea, and creatinine serum level. Tissue and serum levels of LCN2 were significantly diminished in CKD patients following narrowband therapy along with improvement of the severity of pruritus.

CONCLUSIONS

The increased serum and tissue LCN2 expression in CKD pruritic patients and its pronounced decrease, in addition to the improvement of pruritus after treatment, suggest a major pathogenic role of LCN2 in uremic pruritus.

Lipocalin-2: a therapeutic target to overcome neurodegenerative diseases by regulating reactive astrogliosis

Glial cell activation precedes neuronal cell death during brain aging and the progression of neurodegenerative diseases. Under neuroinflammatory stress conditions, lipocalin-2 (LCN2), also known as neutrophil gelatinase-associated lipocalin or 24p3, is produced and secreted by activated microglia and reactive astrocytes. Lcn2 expression levels are known to be increased in various cells, including reactive astrocytes, through the activation of the NF-κB signaling pathway. In the central nervous system, as LCN2 exerts neurotoxicity when secreted from reactive astrocytes, many researchers have attempted to identify various strategies to inhibit LCN2 production, secretion, and function to minimize neuroinflammation and neuronal cell death. These strategies include regulation at the transcriptional, posttranscriptional, and posttranslational levels, as well as blocking its functions using neutralizing antibodies or antagonists of its receptor. The suppression of NF-κB signaling is a strategy to inhibit LCN2 production, but it may also affect other cellular activities, raising questions about its effectiveness and feasibility. Recently, LCN2 was found to be a target of the autophagy‒lysosome pathway. Therefore, autophagy activation may be a promising therapeutic strategy to reduce the levels of secreted LCN2 and overcome neurodegenerative diseases. In this review, we focused on research progress on astrocyte-derived LCN2 in the central nervous system.

Cellular Mechanisms of Psoriasis Pathogenesis: A Systemic Review

Psoriasis is a common inflammatory skin disease characterized by abnormal proliferation of epidermal keratinocytes and massive infiltration of inflammatory cells. Many kinds of cells, including keratinocytes, T lymphocytes, dendritic cells, neutrophils, and macrophages, are reported to play critical roles in the pathogenesis and progression of psoriasis. However, to date, the role of each kind of cell in the pathogenesis and development of psoriasis has not been systematically reviewed. In addition, although antibodies developed targeting cytokines (e.g. IL-23, IL-17A, and TNF-α) released by these cells have shown promising results in the treatment of psoriasis patients, these targeted antibodies still do not cure psoriasis and only provide short-term relief of symptoms. Furthermore, long-term use of these antibodies has been reported to have adverse physical and psychological effects on psoriasis patients. Therefore, gaining a deeper understanding of the cellular and molecular pathogenesis of psoriasis and providing new thoughts on the development of psoriasis therapeutic drugs is of great necessity. In this review, we summarize the roles of various cells involved in psoriasis, aiming to provide new insights into the pathogenesis and development of psoriasis at the cellular level and hoping to provide new ideas for exploring new and effective psoriasis treatments.

Significance of Neutrophil Gelatinase-Associated Lipocalin (NGAL) and Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) for the Monitoring of Treatment Response to Cyclosporine in Patients with Psoriasis

Neutrophil gelatinase-associated lipocalin (NGAL) may promote development of inflammation in psoriasis, whereas proprotein convertase subtilisin/kexin type 9 (PCSK9) may account for dyslipidemia in some psoriatic patients. The aim of the study was to analyze the influence of cyclosporine therapy on serum levels of NGAL and PCSK9 in patients with psoriasis vulgaris.

METHODS

Serum samples were obtained before and after three months cyclosporine therapy. Patients were grouped into responders and non-responders to cyclosporine depending on whether they achieved at least 50% reduction of Psoriatic Activity Score Index (PASI), or not. Serum levels of PCSK9 and NGAL were assayed using commercially available ELISA tests. Lipid levels were measured with an enzymatic method.

RESULTS

There were 40 patients enrolled. A significant decrease in serum NGAL level was seen in cyclosporine responders. No similar dependance was found for PCSK9. Serum PCSK9 concentration correlated with total cholesterol (TChol) and LDL at baseline and after three month treatment.

CONCLUSIONS

Cyclosporine therapy contributes to the reduction of the NGAL serum but not the PCSK9 concentration. Correlation between the PCSK9 serum level and TChol as well as LDL concentration may help to understand drug induced dyslipidemia after cyclosporine.

Lipocalin 2 receptors: facts, fictions, and myths

The human 25-kDa Lipocalin 2 (LCN2) was first identified and purified as a protein that in part is associated with gelatinase from neutrophils. This protein shows a high degree of sequence similarity with the deduced sequences of rat α2-microglobulin-related protein and the mouse protein 24p3. Based on its typical lipocalin fold, which consists of an eight-stranded, anti-parallel, symmetrical β-barrel fold structure it was initially thought that LCN2 is a circulating protein functioning as a transporter of small lipophilic molecules. However, studies in Lcn2 null mice have shown that LCN2 has bacteriostatic properties and plays a key role in innate immunity by sequestering bacterial iron siderophores. Numerous reports have further shown that LCN2 is involved in the control of cell differentiation, energy expenditure, cell death, chemotaxis, cell migration, and many other biological processes. In addition, important roles for LCN2 in health and disease have been identified in Lcn2 null mice and multiple molecular pathways required for regulation of Lcn2 expression have been identified. Nevertheless, although six putative receptors for LCN2 have been proposed, there is a fundamental lack in understanding of how these cell-surface receptors transmit and amplify LCN2 to the cell. In the present review we summarize the current knowledge on LCN2 receptors and discuss inconsistencies, misinterpretations and false assumptions in the understanding of these potential LCN2 receptors.

Gene Ontology Analysis Highlights Biological Processes Influencing Responsiveness to Biological Therapy in Psoriasis

Psoriasis is a chronic, immune-mediated and inflammatory skin disease. Although various biological drugs are available for psoriasis treatment, some patients have poor responses or do not respond to treatment. The aim of the present study was to highlight the molecular mechanism of responsiveness to current biological drugs for psoriasis treatment. To this end, we reviewed previously published articles that reported genes associated with treatment response to biological drugs in psoriasis, and gene ontology analysis was subsequently performed using the Cytoscape platform. Herein, we revealed a statistically significant association between NF-kappaB signaling (p value = 3.37 × 10-9), regulation of granulocyte macrophage colony-stimulating factor production (p value = 6.20 × 10-6), glial cell proliferation (p value = 2.41 × 10-5) and treatment response in psoriatic patients. To the best of our knowledge, we are the first to directly associate glial cells with treatment response. Taken together, our study revealed gene ontology (GO) terms, some of which were previously shown to be implicated in the molecular pathway of psoriasis, as novel GO terms involved in responsiveness in psoriatic disease patients.

The regulation of TRPA1 expression and function by Th1 and Th2-type inflammation in human A549 lung epithelial cells

BACKGROUND

Transient Receptor Potential Ankyrin 1 (TRPA1) is a cation channel that mediates pain, itch, cough, and neurogenic inflammation in response to pungent compounds such as acrolein in cigarette smoke. TRPA1 is also activated by endogenous factors and promotes inflammation in asthma models. We have recently shown that TRPA1 is upregulated by inflammatory cytokines in A549 human lung epithelial cells. Here, we explored the effects of Th1 and Th2-type inflammation on TRPA1.

METHODS AND RESULTS

TRPA1 expression and function was studied in A549 human lung epithelial cells. To induce inflammation, the cells were exposed to a combination of cytokines TNF-α and IL-1β; and to model Th1 or Th2-type responses, IFN-γ or IL-4/IL-13 was added, respectively. TRPA1 expression (measured by RT-PCR and Western blot) and function (assessed by Fluo-3AM intracellular calcium measurement) was enhanced under the influence of TNF-α + IL-1β. IFN-γ further enhanced TRPA1 expression and function, whereas IL-4 and IL-13 suppressed them. The effects of IFN-γ and IL-4 on TRPA1 expression were reversed by the Janus kinase (JAK) inhibitors baricitinib and tofacitinib, and those of IL-4 also by the STAT6 inhibitor AS1517499. The glucocorticoid dexamethasone downregulated TRPA1 expression, whereas the PDE4 inhibitor rolipram had no effect. Under all conditions, TRPA1 blockade was found to reduce the production of LCN2 and CXCL6.

CONCLUSIONS

TRPA1 expression and function in lung epithelial cells was upregulated under inflammatory conditions. IFN-γ further increased TRPA1 expression while IL-4 and IL-13 suppressed that in a JAK-STAT6 dependent manner which is novel. TRPA1 also modulated the expression of genes relevant to innate immunity and lung disease. We propose that the paradigm of Th1 and Th2 inflammation is a major determinant of TRPA1 expression and function, which should be considered when targeting TRPA1 for pharmacotherapy in inflammatory (lung) disease.

Lipocalin 2, synthesized using a cell-free protein synthesis system and encapsulated into liposomes, inhibits the adhesion of Porphyromonas gingivalis to human oral epithelial cells

BACKGROUND AND OBJECTIVE

Lipocalin 2 (LCN2), a glycoprotein expressed in epithelial cells and leukocytes, has an antibacterial effect and plays a role in innate immunity. The delivery of LCN2 encapsulated in liposomes to oral epithelium may be useful to prevent oral infectious diseases. This study aimed to investigate the inhibitory effect of LCN2, artificially synthesized using a cell-free protein synthesis (CFPS) system, on the adhesion of Porphyromonas gingivalis to oral epithelial cells in order to approach oral healthcare using LCN2.

METHODS

LCN 2 was synthesized using a CFPS system and assayed by Western blotting, mass spectrometry and enzyme-linked immunosorbent assay (ELISA). The bilayer liposomes were prepared by the spontaneous transfer method using 1,2-dioleoyl-sn-glycero-3 phosphocholine (DOPC), 3-sn-phosphatidylcholine from Egg Yolk (Egg-PC), and 1,2-dioleoyl-sn-glycero-3 phosphoethanolamine (DOPE). The cellular and medium fractions derived from the culture of oral epithelial cells with liposome-encapsulated LCN2 were assayed by Western blotting and ELISA. The effect of the synthesized LCN2 on adhesion of the labeled P. gingivalis to oral epithelial cells was investigated as an evaluation of its antibacterial activity.

RESULTS

The synthesized LCN2 protein was identified by Western blotting; its amino acid sequence was similar to that of recombinant LCN2 protein. The additions of DOPE and octa-arginine in the outer lipid-layer components of liposome significantly increased the delivery of liposomes to epithelial cells. When oral epithelial cells were cultured with the synthesized and liposome-encapsulated LCN2, LCN2 was identified in the cellular and medium fractions by Western blotting and its concentration in the cellular fraction from the culture with the synthesized LCN2 was significantly higher than that of a template DNA-free protein. The synthesized LCN2 and liposome-encapsulated LCN2 significantly inhibited the adhesion of P. gingivalis to oral epithelial cells compared with template DNA-free protein.

CONCLUSION

LCN2 was artificially synthesized by a CFPS system, encapsulated in liposomes, and delivered to oral epithelial cells, and demonstrated an antibacterial action against P. gingivalis. This approach may become a useful model for oral healthcare.

Perspective insights of small molecules, phytoconstituents and biologics in the management of psoriasis: A focus on targeting major inflammatory cytokine pathways

Psoriasis is an enduring, pruritic and papulosquamous skin ailment that poses a significant burden on public health. It is mainly characterized by hyperkeratosis, acanthosis, parakeratosis, scaly and erythematous plaques. Biomarkers like interleukin-17, interleukin-12 and -23 and tumor necrosis factor-α serve as key drivers of psoriatic pathogenesis. Triggered release of pro-inflammatory cytokines from various up-regulated pathways leads to psoriatic inflammation. Several target moieties like biologics, small molecules and herbal moieties play a fundamental role in the repression of pathogenesis of psoriasis. Biologics and small molecules engaged in the management of psoriasis have been emphasized in detail. An insight into nano-carrier interventions on herbal moieties and clinical aspects of psoriasis are also highlighted. This review emphasizes various pathological targets involved in psoriasis.

Overexpression of lipocalin 2 in PBX1-deficient decidual NK cells promotes inflammation at the maternal-fetal interface

PROBLEM

Impairment of PBX1 expression in decidual natural killer (dNK) cells is associated with the pathogenesis of unexplained recurrent spontaneous abortion, which results in fetal growth restriction (FGR) by affecting the secretion of downstream growth factors. However, whether other mechanisms limit embryo growth in decidua containing PBX1-deficient natural killer (NK) cells is unknown.

METHOD OF STUDY

Pbx1^f/f ; Ncr1^Cre mice were employed to explore the underlying mechanisms by which PBX1^- NK cells affect embryonic development. To simulate the clinical testing of pregnant women, Doppler ultrasound imaging was used to detect embryo implantation and development. Differentially expressed genes (DEGs) in PBX1^- NK cells that may affect normal pregnancy were screened using RNA-sequencing and real-time PCR. Immune cell changes caused by DEGs were detected by flow cytometry. Finally, the mechanism of FGR was explored by injecting the protein LCN2, corresponding to the selected DEG, into mice.

RESULTS

We verified the embryonic dysplasia in pregnant Pbx1^f/f ; Ncr1^Cre mice by Doppler ultrasound imaging and found that LCN2 was upregulated in dNK cells. We also observed higher infiltration of neutrophils and macrophages in the decidua of Pbx1^f/f ; Ncr1^Cre mice. Finally, we found an increase in the number and activation of neutrophils at the maternal-fetal interface after injecting LCN2 into pregnant mice and observed that these mice showed signs of FGR.

CONCLUSION

Excessive LCN2 secreted by PBX1^- dNK cells at the maternal-fetal interface recruit neutrophils and causes an inflammatory response, which is related to FGR.

Decreasing GDF15 Promotes Inflammatory Signals and Neutrophil Infiltration in Psoriasis Models

Psoriasis is driven by the interplay between hyperproliferative keratinocytes and infiltrating inflammatory cells. GDF15, a member of the TGF-β superfamily, has been implicated in cachexia, metabolic control, and cancer invasion. However, the expression and immunomodulatory role of GDF15 in inflammatory diseases has not been clarified. In this study, we report that GDF15 is decreased in the epidermis of patients with psoriasis and in an imiquimod-induced psoriasis-like mouse model. TNF-α suppresses GDF15 expression in keratinocytes by inhibiting the protein level of the transcription factor GATA2. GDF15 deficiency aggravates the development of psoriatic lesions, as evidenced by more severe skin inflammation in imiquimod-treated Gdf15-knockout (Gdf15^‒/‒) mice compared with that in wild-type mice. Importantly, GDF15 limited the synthesis of a panel of keratinocyte cytokines and chemokines by inhibiting TAK1/NF-κB activation and directly inhibited neutrophil adhesion and migration by inhibiting the activation of the small GTPase Rap1. Epidermal hyperplasia, infiltration of neutrophils, and transcripts of psoriasis-related markers in imiquimod-induced psoriasiform dermatitis were significantly alleviated by a topical supplement of recombinant murine GDF15. In summary, our study revealed an unexpected role of GDF15 in keratinocyte and neutrophil function in the skin of psoriasis, implying its therapeutic potential in treating psoriasis.

Induction of psoriasis- and atopic dermatitis-like phenotypes in 3D skin equivalents with a fibroblast-derived matrix

Skin homeostasis is a complex regulated process relying on the crosstalk of keratinocytes, fibroblasts and immune cells. Imbalances of T-cell subsets and the cytokine environment can lead to inflammatory skin diseases such as psoriasis (Ps) and atopic dermatitis (AD). Modern tissue engineering provides several in vitro models mimicking Ps and AD phenotypes. However, these models are either limited in their pathological features, life span, sample availability, reproducibility, controlled handling or simplicity. Some models further lack intensive characterization as they solely focus on differentiation and proliferation aspects. This study introduces a self-assembly model in which the pathological T-cell-signalling of Ps and AD was simulated by subcutaneous Th1 and Th2 cytokine stimulation. The self-established dermal fibroblast-derived matrices of these models were hypothesized to be beneficial for proximal cytokine signalling on epidermal keratinocytes. Comprehensive histological and mRNA analyses of the diseased skin models showed a weakened barrier, distinct differentiation defects, reduced cellular adhesion, inflammation and parakeratosis formation. A keratin shift of declining physiological cytokeratin-10 (CK10) towards increasing inflammatory CK16 was observed upon Th1 or Th2 stimulation. Antimicrobial peptides (AMPs) were upregulated in Ps and downregulated in AD models. The AD biomarker genes CA2, NELL2 and CCL26 were further induced in AD. While Ps samples featured basal hyperproliferation, cells in AD models displayed apoptotic signs. In accordance, these well-controllable three-dimensional in vitro models exhibited Ps and AD-like phenotypes with a high potential for disease research and therapeutic drug testing.

Banzhilian formula alleviates psoriasis-like lesions via the LCN2/MMP-9 axis based on transcriptome analysis

Introduction: Oral Banzhilian formula (BZLF) is effective in the clinical treatment of psoriasis. However, the effectiveness and mechanism of different drug delivery routes deserve further study. Methods: First, we established the mouse model of psoriasis using imiquimod (IMQ), and high-performance liquid chromatography (HPLC) was used for the quality control of BZLF. Secondly, Total RNA Sequencing and bioinformatics analysis were used to explore the regulatory mechanism of BZLF in improving psoriatic lesions. Finally, further verification was based on animal experiments. Results: we externally applied BZLF for skin lesions in an imiquimod-induced psoriasis mouse model and found that BZLF alleviated psoriasis-like skin lesions while inhibiting the expression of Ki67 and inflammatory factors (Il17a, Tnf-α, S100a7 and Cxcl1) in skin lesions. Transcriptome sequencing results suggested that BZLF inhibited signalling pathways closely related to psoriatic inflammation, such as the IL-17 signalling pathway, chemokine signalling pathway, TNF signalling pathway, and NF-kappa B signalling pathway, and the protein-protein interaction (PPI) network identified LCN2 as one of the core target genes and screened out its regulated downstream gene MMP9. Discussion: Our findings suggest that the anti-psoriatic mechanism of BZLF involved in downregulating the LCN2/MMP-9 axis.

Combination of IL-17A/F and TNF-α uniquely alters the bronchial epithelial cell proteome to enhance proteins that augment neutrophil migration

Background

The heterodimer interleukin (IL)-17A/F is elevated in the lungs in chronic respiratory disease such as severe asthma, along with the pro-inflammatory cytokine tumor necrosis factor-α (TNF-α). Although IL-17A/F and TNF-α are known to functionally cooperate to exacerbate airway inflammation, proteins altered by their interaction in the lungs are not fully elucidated.

Results

We used Slow Off-rate Modified Aptamer-based proteomic array to identify proteins that are uniquely and/or synergistically enhanced by concurrent stimulation with IL-17A/F and TNF-α in human bronchial epithelial cells (HBEC). The abundance of 38 proteins was significantly enhanced by the combination of IL-17A/F and TNF-α, compared to either cytokine alone. Four out of seven proteins that were increased > 2-fold were those that promote neutrophil migration; host defence peptides (HDP; Lipocalin-2 (LCN-2) and Elafin) and chemokines (IL-8, GROα). We independently confirmed the synergistic increase of these four proteins by western blots and ELISA. We also functionally confirmed that factors secreted by HBEC stimulated with the combination of IL-17A/F and TNF-α uniquely enhances neutrophil migration. We further showed that PI3K and PKC pathways selectively control IL-17A/F + TNF-α-mediated synergistic production of HDPs LCN-2 and Elafin, but not chemokines IL-8 and GROα. Using a murine model of airway inflammation, we demonstrated enhancement of IL-17A/F, TNF-α, LCN-2 and neutrophil chemokine KC in the lungs, thus corroborating our findings in-vivo.

Conclusion

This study identifies proteins and signaling mediated by concurrent IL-17A/F and TNF-α exposure in the lungs, relevant to respiratory diseases characterized by chronic inflammation, especially neutrophilic airway inflammation such as severe asthma.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12950-022-00323-w.

Neutrophil Gelatinase-Associated Lipocalin as Potential Predictive Biomarker of Melanoma and Non-Melanoma Skin Cancers in Psoriatic Patients: A Pilot Study

Background: Studies have demonstrated a higher risk of nonmelanoma skin cancers (NMSC) and a modestly increased melanoma risk in patients with psoriasis. To date, no biomarkers predictive of evolution have been identified yet. Methods: The aim of this prospective case-control study was to investigate the potential role of neutrophil gelatinase-associated lipocalin (NGAL) as a predictive biomarker of skin cancers in psoriatic patients. Patients with a diagnosis of psoriasis were enrolled, as well as healthy subjects and patients with skin cancers as controls. Plasma protein expression of NGAL, metalloproteinases (MMP)-2, and MMP-9 was performed by an enzyme-linked immunosorbent assay (ELISA). In all the patients who developed skin cancer at follow-up, NGAL, MMP-2, and MMP-9 serum levels were dosed again. Results: Plasma NGAL levels were significantly higher in psoriatic patients with NMSC than without (182.3 ± 36.6 ng/mL vs. 139.9 ± 39.3 ng/mL) (p < 0.001). Plasma NGAL levels were significantly higher (p < 0.00001) in patients with psoriasis and NMSC than in patients with skin tumors without psoriasis (182.3 vs. 122.9). Patients with psoriasis who developed NMSC at follow-up showed increased plasma MMP-9 levels. Conclusion: NGAL seems to play a role in the pathogenesis of NMSC but not melanoma in patients with psoriasis.

The role of lipocalin 2 in brain injury and recovery after ischemic and hemorrhagic stroke

Ischemic and hemorrhagic stroke (including intracerebral hemorrhage, intraventricular hemorrhage, and subarachnoid hemorrhage) is the dominating cause of disability and death worldwide. Neuroinflammation, blood–brain barrier (BBB) disruption, neuronal death are the main pathological progress, which eventually causes brain injury. Increasing evidence indicated that lipocalin 2 (LCN2), a 25k-Da acute phase protein from the lipocalin superfamily, significantly increased immediately after the stroke and played a vital role in these events. Meanwhile, there exists a close relationship between LCN2 levels and the worse clinical outcome of patients with stroke. Further research revealed that LCN2 elimination is associated with reduced immune infiltrates, infarct volume, brain edema, BBB leakage, neuronal death, and neurological deficits. However, some studies revealed that LCN2 might also act as a beneficial factor in ischemic stroke. Nevertheless, the specific mechanism of LCN2 and its primary receptors (24p3R and megalin) involving in brain injury remains unclear. Therefore, it is necessary to investigate the mechanism of LCN2 induced brain damage after stroke. This review focuses on the role of LCN2 and its receptors in brain injury and aiming to find out possible therapeutic targets to reduce brain damage following stroke.

Critical Players and Therapeutic Targets in Chronic Itch

Chronic itch is one of the most prominent clinical characteristics of diverse systematic diseases. It is a devastating sensation in pathological diseases. Despite its importance, there are no FDA-labelled drugs specifically geared toward chronic itch. The associated complex pathogenesis and diverse causes escalate chronic itch to being one of the top challenges in healthcare. Humanized antibodies against IL-13, IL-4, and IL-31 proved effective in treatment of itch-associated atopic dermatitis but remain to be validated in chronic itch. There are still no satisfactory anti-itch therapeutics available toward itch-related neuropeptides including GRP, BNP, SST, CGRP, and SP. The newly identified potential itch targets including OSM, NMB, glutamate, periostin, and Serpin E1 have opened new avenues for therapeutic development. Proof-of-principle studies have been successfully performed on antagonists against these proteins and their receptors in itch treatment in animal models. Their translational interventions in humans need to be evaluated. It is of great importance to summarize and compare the newly emerging knowledge on chronic itch and its pathways to promote the development of novel anti-itch therapeutics. The goal of this review is to analyze the different physiologies and pathophysiologies of itch mediators, whilst assessing their suitability as new targets and discussing future therapeutic development.

Interplay Between the Immune and Endocrine Systems in the Lung: Implications for TB Susceptibility

The role of the endocrine system on the immune response, especially in the lung, remains poorly understood. Hormones play a crucial role in the development, homeostasis, metabolism, and response to the environment of cells and tissues. Major infectious and metabolic diseases, such as tuberculosis and diabetes, continue to converge, necessitating the development of a clearer understanding of the immune and endocrine interactions that occur in the lung. Research in bacterial respiratory infections is at a critical point, where the limitations in identifying and developing antibiotics is becoming more profound. Hormone receptors on alveolar and immune cells may provide a plethora of targets for host-directed therapy. This review discusses the interactions between the immune and endocrine systems in the lung. We describe hormone receptors currently identified in the lungs, focusing on the effect hormones have on the pulmonary immune response. Altered endocrine responses in the lung affect the balance between pro- and anti-inflammatory immune responses and play a role in the response to infection in the lung. While some hormones, such as leptin, resistin and lipocalin-2 promote pro-inflammatory responses and immune cell infiltration, others including adiponectin and ghrelin reduce inflammation and promote anti-inflammatory cell responses. Furthermore, type 2 diabetes as a major endocrine disease presents with altered immune responses leading to susceptibility to lung infections, such as tuberculosis. A better understanding of these interactions will expand our knowledge of the mechanisms at play in susceptibility to infectious diseases and may reveal opportunities for the development of host-directed therapies.

Serum and Urinary Neutrophil Gelatinase-Associated Lipocalin Are Not Associated With Serum Redox Parameters in Amateur Athletes After an Ultramarathon

Objective

To evaluate the relationship between oxidative stress and NGAL levels in blood and urine of amateur athletes after participating in a 100 km ultramarathon.

Methodology

The sample was composed of seven athletes, submitted to anthropometric assessment, cardiopulmonary exercise test, collection of urine and blood, measurement of body weight. The rate of perceived exertion (RPE), competition duration, heart rate (HR), energy expenditure and oxygen consumption (V'O2") were also measured during the event. The energy consumption during the race was verified at its end. The analyses were based on the means (M) and respective standard deviations (SD), with statistical significance set at 5% (p < 0.05). Paired t-test was used for comparison between the periods before and after the competition, and Pearson's correlation coefficient was used to measure the linear correlation between quantitative variables.

Results

Body mass index (BMI) of the sample was 25.75 kg/m2 ± 3.20, body fat percentage 18.54% ± 4.35% and V'O2"max 48.87% ± 4.78. Glucose, cortisol, and neutrophil gelatinase-associated lipocalin (NGAL) (p < 0.01) as well as glutathione peroxidase (GPx) active were higher after the race when compared to basal values. Moreover, lactate, creatinine, microalbuminuria, and glomerular filtration rate (GFR) (p < 0.001) were also higher after the race. After the competition, there was a significant correlation only between serum NGAL and creatinine, which was classified as strong and positive (r: 0.77; p < 0.05). There was a significant reduction (p < 0.05) of body weight after the event (72.40 kg ± 9.78) compared to before it (73.98 kg ± 10.25). In addition, we found an increase of RPE (p < 0.001) after the race. The competition lasted 820.60 min (±117.00), with a 127.85 bpm (±12.02) HR, a 2209.72 kcal ± 951.97 energy consumption, 7837.16 kcal ± 195.71 energy expenditure, and 28.78 ml/kg/min-1 (±4.66) relative V'O2"max.

Conclusion

The lack of correlation between oxidative stress biomarkers and serum and urine NGAL suggests that NGAL is more sensitive to inflammatory processes than to ROS levels.

Lipocalin 2 Participates in the Epidermal Differentiation and Inflammatory Processes of Psoriasis

As a multifunctional cytokine, lipocalin 2 is weakly expressed in skin and serum under normal conditions. However, it is over-expressed by neutrophils and keratinocytes in the skin lesions and sera in several skin diseases. Recent studies demonstrated that lipocalin 2 participates in the pathogenesis of psoriasis by exerting versatile effects on skin resident cells and infiltrating immune cells. Lipocalin 2 inhibits the synthesis of keratin, involucrin, and loricrin in keratinocytes, leading to epidermal parakeratosis via the Tcf7l1-lipocalin 2 signaling axis. It also recruits inflammatory cells such as T cells and neutrophils into skin lesions via the IL-23/IL17, p38-MAPK, and ERK-1/2 signaling pathways. Additionally, lipocalin 2 and other cytokines such as IL-17 have the synergetic effects on skin cells. The neutralization of lipocalin 2 or relevant cytokines can alleviate psoriasis, verifying that lipocalin 2 is an effective interfering target for psoriasis. In this review, we summarize the roles of lipocalin 2 in the processes of psoriatic inflammation and the promising therapeutic strategies based on lipocalin 2-related molecules.

IL-17RA blockade by brodalumab decreases inflammatory pathways in hidradenitis suppurativa skin and serum

BACKGROUND

Hidradenitis suppurativa (HS) is an inflammatory skin disease with dysregulation of the IL-17 axis. Recently we reported clinical benefit of brodalumab, a human anti-IL-17 receptor A (IL-17RA) monoclonal antibody, in moderate-to-severe HS.

OBJECTIVES

To characterize the molecular response to brodalumab in HS skin and serum, and to identify biomarkers of treatment response.

METHODS

Ten participants that received 210 mg/1.5mL brodalumab subcutaneously at week 0, 1, 2, 4 and every 2 weeks after were included in this molecular profiling study (NCT03960268). RNA-sequencing and immunohistochemistry of nonlesional, perilesional and lesional HS skin biopsies, and Olink high throughput proteomics of serum at baseline, week 4 and week 12 were assessed.

RESULTS

At week 12, brodalumab led to a decrease of overall inflammation, and improvement of psoriasis-, keratinocyte- and neutrophil-related pathways. Despite perilesional and lesional skin having no differentially expressed genes at baseline, treatment response was best assessed in perilesional skin. In serum, brodalumab treatment decreased pathways involved in neutrophil inflammation. Patients with higher baseline expression of neutrophil-associated Lipocalin-2 (LCN2) in the skin and IL-17A in the serum demonstrated greater decreases of HS-related inflammatory cytokines as measured in skin biopsies at week 12.

CONCLUSIONS

IL-17RA inhibition by brodalumab impacts several pathogenic inflammatory axes in HS. Perilesional skin provides a valid and robust assessment of treatment response. Expression of LCN2 in skin and IL-17A in serum may be used as biomarkers to stratify patients that may have a superior molecular response to brodalumab =.

TMT-based proteomics analysis reveals the protective effect of Jueyin granules on imiquimod-induced psoriasis mouse model by causing autophagy

BACKGROUND

Psoriasis is a chronic relapsing inflammatory skin disease that may markedly influence the patients' physical health and mental condition. According to animal models and clinical researches, it has been proved that Jueyin granules (JYG), a Chinese formula comprised of seven kinds of Traditional Chinese Medicine (TCM), is a therapeutic agent for treating psoriasis, while the specific mechanisms of the anti-inflammation effects of JYG have not been fully elucidated.

OBJECTIVE

To uncover the underlying mechanisms of the action of JYG on psoriasis by proteomics clues.

MATERIALS AND METHODS

Differentially expressed proteins (DEPs) were explored by tandem mass tag (TMT)-based quantitative proteomics analysis after JYG treatment (administered intragastrically for 12 days). Bioinformatics analysis of DEPs was conducted through hierarchical clustering, volcano plot, gene ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Major DEPs were further identified by enzyme-linked immunoassay (ELISA) and real-time quantitative polymerase chain reaction (qRT-PCR).

RESULTS

Ninety-five DEPs were identified, including 57 up-regulated and 38 down-regulated proteins, between imiquimod (IMQ) and IMQ+JYG groups. GO analysis indicated that DEPs were mainly associated with keratin filament, intermediate filament, extracellular exosome, extracellular space, innate immune response, keratinization, and keratinocyte differentiation. The KEGG pathway analysis manifested that estrogen signaling pathway, cholesterol metabolism, fat digestion, absorption, peroxisome proliferator-activated receptor (PPAR), and interleukin (IL)-17 signaling pathway might be the paramount pathways, through which JYG functioned on psoriasis. Furthermore, we determined that JYG could regulate macrophage and CD4+ T cell phenotypes by inducing autophagy.

CONCLUSIONS

JYG may induce autophagy by up-regulating ApoA1 and inhibit the infiltration of CD4+ T cells and macrophages, thereby alleviating IMQ-induced psoriatic inflammation.

Lipocalin 2 Mediates Skin Inflammation in Psoriasis via the SREBP2-NLRC4 Axis

Lipocalins are a family of secreted adipokines that regulate cell lipid metabolism and immune responses. Although we have previously revealed that lipocalin 2 (LCN2) modulates neutrophil activation in psoriasis, the other roles of LCN2 in psoriatic local inflammation have remained elusive. Here, we found that 24p3R, the well-known specific receptor of LCN2, was highly expressed in the lesional epidermis of psoriasis patients. Silencing 24p3R alleviated hyperkeratosis, inflammatory cell infiltration, and overexpression of inflammatory mediators in an imiquimod (IMQ)-induced psoriasis-like mouse model. In vitro, LCN2 enhanced the expression of pro-inflammatory factors in primary keratinocytes, such as interleukin (IL)-1β, IL-23, C-X-C motif chemokine ligand (CXCL)1, and CXCL10, which was paralleled by enforced cholesterol biosynthetic signaling. Importantly, taking in vivo and in vitro approaches, we discovered the sterol response element binding factor 2 (SREBP2), a vital transcriptional factor in cholesterol synthesis pathway, as the critical mediator of LCN2-induced keratinocyte activation, which bond to the promoter region of NLR-family CARD-containing protein 4 (NLRC4). Suppressing SREBP2 in mice attenuated NLRC4 signaling and psoriasis-like dermatitis. Taken together, this study identifies the critical role of LCN2-SREBP2-NLRC4 axis in the pathogenesis of psoriasis, and proposes 24p3R or SREBP2 as potential therapeutic target for psoriasis.

Principal Component Analysis to Differentiate Patients with Palmoplantar Pustulosis from Those with Palmoplantar Pustular Psoriasis

Background

Palmoplantar pustulosis (PPP) is initiated from the acrosyringium. However, it is unclear whether PPP should be considered a distinct entity or should be classified into the spectrum of pustular psoriasis, also known as palmoplantar pustular psoriasis (PPPP).

Objective

We evaluated the differences in immunohistochemical staining in patients with PPP to determine whether they can be classified into two groups based on psoriatic properties or acrosyringeal properties.

Methods

Nineteen punch biopsy specimens diagnosed with PPP were collected. Antibodies were chosen for identifying the acrosyringeal properties of α-3-nicotine acetylcholine receptors (α-3-nAChR), psoriatic properties of interleukin (IL)-23 and IL-36R, inflammatory cell properties of human cathelicidin antimicrobial peptide 18/LL-37, IL-8, lipocalin-2 (LCN2), and CD3. The degree of staining of the epidermis was evaluated using the ordinal scale (0~3). The principal component analysis was used to derive principal components (PCs) of common variation between the stains, and the two groups were divided using PCs and cluster analysis.

Results

Three main PCs explained 64% of the total variance in PPP. PC1 (pustular psoriasis properties) showed a higher correlation with IL-36R. PC2 (acrosyringeal/inflammatory properties) showed a higher correlation with α-3-nAChR, IL-8, LCN2, and CD3. PC3 (psoriasis properties) showed a higher correlation with IL-23. PC1 showed a statistically significant difference (p=0.0284) between the two groups. We identified three PCs associated with the pathomechanisms of PPP.

Conclusion

Although PC1 showed a statistically significant difference between the two groups, we did not identify differential protein expression related to the pathogenesis between PPP and PPPP.

Neutrophil gelatinase-associated lipocalin as an immunomodulator in endocrine hypertension

In recent studies, primary aldosteronism (PA) has been reported as the most common etiology for secondary hypertension of endocrine origin, accounting for approximately 10% of cases. In PA, excess aldosterone production can lead to deleterious effects at the cardiovascular (CV) and renal levels by activating mineralocorticoid receptors, which involves an increase in pro-inflammatory and pro-fibrotic mediators. Among these mediators, neutrophil gelatinase-associated lipocalin (NGAL), a secretion glycoprotein belonging to the lipocalin superfamily, has been closely linked to CV and renal damage in several pathological conditions. Because NGAL can be detected in biofluids such as plasma and urine, it has been proposed as a damage biomarker for target tissues and has also been studied for its role in hypertension and associated with PA. NGAL is produced by many different cell types, can be carried on extracellular vesicles, and is modulated by microRNAs, which would support its use as a biomarker for endocrine hypertension due to PA. Over the last decade, studies have shown that NGAL is necessary for the development of aldosterone-induced hypertension and that is associated with end-organ damage. In addition, it has been proposed that some mechanisms are dependent on the activation of immune cells, such as dendritic cells and macrophages, where the release of specific cytokines (i.e., interleukin [IL]-23) or chemokines (i.e., CCL-5) induced by aldosterone would depend on NGAL. Subsequently, this activates the T helper (Th) lymphocytes, such as Th₁₇ and Th₂, resulting in CV and renal fibrosis due to the high aldosterone levels. Although the immune system has been closely associated with essential hypertension, its participation in endocrine hypertension has not been fully elucidated. This review discusses the link between NGAL and endocrine hypertension, particularly in the context of PA, and their possible regulators and mechanisms, with a focus on its role as an immunomodulator.

Neutrophil Pathways of Inflammation Characterize the Blood Transcriptomic Signature of Patients with Psoriasis and Cardiovascular Disease

BACKGROUND

Patients with psoriasis have an increased risk of atherosclerotic cardiovascular disease (CVD). The molecular mechanisms behind this connection are not fully understood, but the involvement of neutrophils have drawn attention as a shared inflammatory factor.

METHODS

RNA sequencing using the Illumina platform was performed on blood from 38 patients with moderate to severe psoriasis; approximately half had prior CVD. The neutrophil to lymphocyte ratio (NLR) was obtained from blood samples. Subclinical atherosclerosis was assessed by ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography and ultrasound imaging. Transcriptomic analysis for differential expression and functional enrichment were performed, followed by correlation analyses of differentially expressed genes (DEGs), NLR and subclinical measurers of CVD.

RESULTS

291 genes were differentially expressed between patients with psoriasis with and without CVD. These included 208 upregulated and 83 downregulated DEGs. Neutrophil degranulation was identified as the most significant process related to the upregulated DEGs. Genes for the neutrophil-associated markers MPO, MMP9, LCN2, CEACAM1, CEACAM6 and CEACAM8 were identified as being of special interest and their mRNA levels correlated with NLR, high-sensitive C-reactive protein and markers of subclinical CVD.

CONCLUSIONS

Patients with psoriasis and CVD had an increased expression of genes related to neutrophil degranulation in their blood transcriptome compared with patients with psoriasis without CVD. NLR may be a potential biomarker of subclinical CVD in psoriasis.

Lipocalin 2 promotes inflammatory breast cancer tumorigenesis and skin invasion

Inflammatory breast cancer (IBC) is an aggressive form of primary breast cancer characterized by rapid onset and high risk of metastasis and poor clinical outcomes. The biological basis for the aggressiveness of IBC is still not well understood and no IBC-specific targeted therapies exist. In this study, we report that lipocalin 2 (LCN2), a small secreted glycoprotein belonging to the lipocalin superfamily, is expressed at significantly higher levels in IBC vs non-IBC tumors, independently of molecular subtype. LCN2 levels were also significantly higher in IBC cell lines and in their culture media than in non-IBC cell lines. High expression was associated with poor-prognosis features and shorter overall survival in IBC patients. Depletion of LCN2 in IBC cell lines reduced colony formation, migration, and cancer stem cell populations in vitro and inhibited tumor growth, skin invasion, and brain metastasis in mouse models of IBC. Analysis of our proteomics data showed reduced expression of proteins involved in cell cycle and DNA repair in LCN2-silenced IBC cells. Our findings support that LCN2 promotes IBC tumor aggressiveness and offer a new potential therapeutic target for IBC.

CSF lipocalin-2 increases early in subarachnoid hemorrhage are associated with neuroinflammation and unfavorable outcome

Lipocalin-2 mediates neuro-inflammation and iron homeostasis in vascular injuries of the central nervous system (CNS) and is upregulated in extra-CNS systemic inflammation. We postulate that cerebrospinal fluid (CSF) and blood lipocalin-2 levels are associated with markers of inflammation and functional outcome in subarachnoid hemorrhage (SAH). We prospectively enrolled 67 SAH subjects, serially measured CSF and plasma lipocalin-2, matrix metallopeptidase 9 (MMP-9), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) on post-SAH days 1-5 and assessed outcome by modified Rankin Scale (mRS) every 3 months. Unfavorable outcome is defined as mRS > 2. Twenty non-SAH patients undergoing lumbar drain trial were enrolled as controls. Lipocalin-2 was detectable in the CSF and significantly higher in SAH compared to controls (p < 0.0001). Higher CSF LCN2 throughout post-SAH days 1-5 was associated with unfavorable outcome at 3 (p = 0.0031) and 6 months (p = 0.014). Specifically, higher CSF lipocalin-2 on post-SAH days 3 (p = 0.036) and 5 (p = 0.016) were associated with unfavorable 3-month outcome. CSF lipocalin-2 levels positively correlated with CSF IL-6, TNF-α and MMP-9 levels. Higher plasma lipocalin-2 levels over time were associated with worse 6-month outcome. Additional studies are required to understand the role of lipocalin-2 in SAH and to validate CSF lipocalin-2 as a potential biomarker for SAH outcome.

Comprehensive review of lipocalin 2-mediated effects in lung inflammation

Lipocalin-2 (LCN2) is an inflammatory mediator best known for its role as an innate acute-phase protein. LCN2 mediates the innate immune response to pathogens by sequestering iron, thereby inhibiting pathogen growth. Although LCN2 and its bacteriostatic properties are well studied, other LCN2 functions in the immune response to inflammatory stimuli are less well understood, such as its role as a chemoattractant and involvement in the regulation of cell migration and apoptosis. In the lungs, most studies thus far investigating the role of LCN2 in the immune response have looked at pathogenic inflammatory stimuli. Here, we compile data that explore the role of LCN2 in the immune response to various inflammatory stimuli in an effort to differentiate between protective versus detrimental roles of LCN2.

Lipocalin-2: Structure, function, distribution and role in metabolic disorders

Lipocalin-2 (LCN-2) is a novel, 198 amino acid adipocytokine also referred to as neutrophil gelatinase-associated lipocalin (NGAL). LCN-2 is a circulatory protein responsible for the transportation of small and hydrophobic molecules (steroid, free fatty acids, prostaglandins and hormones) to target organs after binding to megalin/glycoprotein and GP330 SLC22A17 or 24p3R LCN-2 receptors. LCN-2 has been used as a biomarker for acute and chronic renal injury. It is present in a large variety of cells including neutrophil, hepatocytes, lung, bone marrow, adipose tissue, macrophages, thymus, non-neoplastic breast duct, prostate, and renal cells. Different functions have been associated with LCN-2. These functions include antibacterial, anti-inflammatory, and protection against cell and tissue stress. Moreover, LCN-2 can increase the pool of matrix metalloproteinase 9 in human neutrophil granulocytes. Other reported functions of LCN-2 include its ability to destroy the extracellular matrix, which could enable cancer progression and spread of metastasis. Recent reports show that the tissue level of LCN-2 is increased in metabolic disorders such as obesity and type 2 diabetes, suggesting an association between LCN-2 and insulin sensitivity and glucose homeostasis. The precise role of LCN-2 in the modulation of insulin sensitivity, glucose and lipid metabolism is still unclear. This review explores the structure of LCN-2, tissue distribution, and its interaction with important metabolic pathways.

Lipocalin 2 as a link between ageing, risk factor conditions and age-related brain diseases

Chronic (neuro)inflammation plays an important role in many age-related central nervous system (CNS) diseases, including Alzheimer's disease, Parkinson's disease and vascular dementia. Inflammation also characterizes many conditions that form a risk factor for these CNS disorders, such as physical inactivity, obesity and cardiovascular disease. Lipocalin 2 (Lcn2) is an inflammatory protein shown to be involved in different age-related CNS diseases, as well as risk factor conditions thereof. Lcn2 expression is increased in the periphery and the brain in different age-related CNS diseases and also their risk factor conditions. Experimental studies indicate that Lcn2 contributes to various neuropathophysiological processes of age-related CNS diseases, including exacerbated neuroinflammation, cell death and iron dysregulation, which may negatively impact cognitive function. We hypothesize that increased Lcn2 levels as a result of age-related risk factor conditions may sensitize the brain and increase the risk to develop age-related CNS diseases. In this review we first provide a comprehensive overview of the known functions of Lcn2, and its effects in the CNS. Subsequently, this review explores Lcn2 as a potential (neuro)inflammatory link between different risk factor conditions and the development of age-related CNS disorders. Altogether, evidence convincingly indicates Lcn2 as a key constituent in ageing and age-related brain diseases.

Randialic acid B and tomentosolic acid block formyl peptide receptor 1 in human neutrophils and attenuate psoriasis-like inflammation in vivo

Psoriasis is a long-lasting inflammatory skin disease lacking proper cure. Dysregulated activation of neutrophils is a major pathogenic factor in psoriasis. Formyl peptide receptor 1 (FPR1) triggers neutrophil activation in response to bacteria- or mitochondria-derived N-formyl peptides, but its significance in neutrophilic psoriasis remains unknown. In this study, we discovered two derivatives of ursolic acid, 3β-hydroxyurs-12,18-dien-28-oic acid (randialic acid B, RAB) and 3β-hydroxyurs-12,19-dien-28-oic acid (tomentosolic acid, TA), as FPR1 inhibitors in human neutrophils with ability to suppress psoriatic symptoms in mice. Both RAB and TA, triterpenoids of traditional medicinal plant Ilex kaushue, selectively inhibited reactive oxygen species production, elastase release, and CD11b expression in human neutrophils activated by FPR1, but not non-FPR1 agonists. Importantly, RAB and TA inhibited the binding of N-formyl peptide to FPR1 in human neutrophils, neutrophil-like THP-1 cells, and hFPR1-transfected HEK293 cells, indicating FPR1 antagonism. Moreover, in assays induced by various concentrations of FPR1 agonist, both RAB and TA acted competitively for its binding to the FPR1 receptor. The FPR1-downstream signaling such as Ca2+ mobilisation and activation of Akt and MAPKs was also competitively inhibited. In addition, imiquimod-induced psoriasis-like symptoms, including epidermal hyperplasia, desquamation with scaling, neutrophil skin infiltration, and transepidermal water loss were significantly reduced by both RAB and TA. The results illustrate a possible role of human neutrophils FPR1 receptor in psoriasis-like inflammation. Accordingly, triterpenoids RAB and TA represent novel FPR1 antagonists and exhibit therapeutic potential for treating neutrophilic inflammatory skin diseases.

Serum lipocalin-2 and carotid artery intima-media thickness in relation to obesity in eugonadal males over forty with venogenic erectile dysfunction

Obesity is a risk factor for erectile dysfunction and atherosclerosis. Lipocalin-2 is an adipocytokine with proinflammatory properties involved in several disorders with metabolic alterations. Our aim was to study the relation of serum lipocalin-2 and carotid artery intima-media thickness (CIMT) to obesity in erectile dysfunction. Serum lipocalin-2 and CIMT were measured in 25 obese and 25 nonobese eugonadal patients over forty with venogenic erectile dysfunction and 25 healthy controls. Their relation to different patient- and disease-related parameters was studied. Results revealed lipocalin-2 to be significantly higher in obese compared with nonobese patients and with controls, and in nonobese patients compared with controls. CIMT was lower in controls compared with both obese and nonobese patients. In obese and nonobese patients, lipocalin-2 was positively correlated with disease duration, body mass index, waist circumference and end-diastolic velocity. Lipocalin-2 was negatively correlated with the short form of the international index of erectile function scores in both groups. In conclusion, the elevated lipocalin-2 in obese and to a lesser extent in nonobese patients and its association with disease severity points to its potential value as a diagnostic marker and a possible therapeutic target that could ameliorate the metabolic derangement associated with erectile dysfunction.

miR-383 reduces keratinocyte proliferation and induces the apoptosis in psoriasis via disruption of LCN2-dependent JAK/STAT pathway activation

Psoriasis is a chronic and relapsing disorder with considerable negative effects on patients' quality of life. The finer details associated with the molecular mechanism of psoriasis and its pathogenesis remain somewhat elusive. Extensive studies have highlighted the crucial role of microRNAs (miRNAs) in the development of psoriasis. Hence, the current study aimed to investigate the effect of miR-383 on a psoriasis rat model and elucidate the underlying molecular mechanism. The rat psoriasis model was established via imiquimod (IMQ) induction followed by verification of miR-383 and LCN2 expression in the skin tissues of the models. ELISA was conducted to determine the secretion of inflammatory factors. Keratinocyte proliferation and apoptosis was evaluated by MTT assay and flow cytometric analysis. Down-regulation of miR-383 and up-regulation of LCN2 were detected in the psoriasis rat model. Our data indicated that miR-383 targeted LCN2 by binding to its 3'UTR and inhibited JAK/STAT pathway activation. Notably, miR-383 overexpression or LCN2 knockdown attenuated psoriasis-like symptoms, suppressed inflammatory response, reduced the expression of JAK3 and STAT3, ceased keratinocyte proliferation, and promoted the apoptosis. The findings of our study suggest that miR-383 may inhibit LCN2 and inactivate the JAK/STAT pathway, suppressing the progression of psoriasis in a rat model. This study provided novel insights into the pathogenesis of psoriasis and offered potential targets for psoriasis treatment.

Regulation of the Nfkbiz Gene and Its Protein Product IkBζ in Animal Models of Sepsis and Endotoxic Shock

Sepsis is a life-threatening condition that arises from a poorly regulated inflammatory response to pathogenic organisms. Current treatments are limited to antibiotics, fluid resuscitation, and other supportive therapies. New targets for monitoring disease progression and therapeutic interventions are therefore critically needed. We previously reported that lipocalin-2 (Lcn2), a bacteriostatic mediator with potent proapoptotic activities, was robustly induced in sepsis. Other studies showed that Lcn2 was a predictor of mortality in septic patients. However, how Lcn2 is regulated during sepsis is poorly understood. We evaluated how IkBζ, an inducer of Lcn2, was regulated in sepsis using both the cecal ligation and puncture (CLP) and endotoxemia (lipopolysaccharide [LPS]) animal models. We show that Nfkbiz, the gene encoding IkBζ, was rapidly stimulated but, unlike Lcn2, whose expression persists during sepsis, mRNA levels of Nfkbiz decline to near basal levels several hours after its induction. In contrast, we observed that IkBζ expression remained highly elevated in septic animals following CLP but not LPS, indicating the occurrence of a CLP-specific mechanism that extends IkBζ half-life. By using an inhibitor of IkBζ, we determined that the expression of Lcn2 was largely controlled by IkBζ. Altogether, these data indicate that the high IkBζ expression in tissues likely contributes to the elevated expression of Lcn2 in sepsis. Since IkBζ is also capable of promoting or repressing other inflammatory genes, it might exert a central role in sepsis.

Identification of Hub Genes and Immune Infiltration in Psoriasis by Bioinformatics Method

Background

Psoriasis is a chronic, prolonged, and recurrent skin inflammatory disease. However, the pathogenesis of psoriasis is not completely clear, thus we aimed to explore potential molecular basis of it.

Methods

Two datasets were downloaded from the Gene Expression Omnibus database. After identifying the differentially expressed genes of psoriasis skin lesion samples and healthy controls, three kinds of analyses, namely functional annotation, protein-protein interaction (PPI) network, and immune infiltration analyses, were performed.

Results

A total of 152 up-regulated genes and 38 down-regulated genes were selected for subsequent analyses. Evaluation of the PPI network identified the most important module containing 13 hub genes. Gene ontology analysis showed that the hub genes have a significant enrichment effect on positive regulation of cell migration, defense response to the other organism and epithelial cell differentiation. KEGG signaling pathway analysis showed that the hub genes were significantly enriched in chemokine signaling, Toll-like receptor signaling pathway, and IL-17 signaling pathway. Compared with the normal control sample, naive B cells, CD8⁺ T cells, activated memory CD4⁺ T cells, follicular helper T cells, gamma delta T cells, resting NK cells, monocytes, M0 macrophages, M1 macrophages, activated dendritic cells and neutrophils infiltrated more, while memory B cells, naive CD4⁺ T cells, regulatory T cells (Tregs), activated NK cells, resting mast cells, and eosinophils infiltrated less.

Conclusion

To conclude, the hub genes and pathways identified from psoriasis lesions and normal controls along with the immune infiltration profile may provide new insights into the study of psoriasis.

Identifying key components and therapeutic targets of the immune system in hidradenitis suppurativa with an emphasis on neutrophils

Hidradenitis suppurativa (HS) is a chronic, inflammatory, recurrent and debilitating skin disease of the hair follicle unit that typically develops after puberty. The disorder is characterized by comedones, painful inflammatory nodules, abscesses, dermal tunnels and scarring, with a predilection for intertriginous areas of the body (axillae, inguinal and anogenital regions). Recruitment of neutrophils to HS lesion sites may play an essential role in the development of the painful inflammatory nodules and abscesses that characterize the disease. This is a review of the major mediators involved in the recruitment of neutrophils to sites of active inflammation, including bacterial components (endotoxins, exotoxins, capsule fragments, etc.), the complement pathway anaphylatoxins C3a and C5a, tumour necrosis factor-alpha, interleukin (IL)-17, IL-8 (CXCL8), IL-36, IL-1, lipocalin-2, leukotriene B4, platelet-activating factor, kallikreins, matrix metalloproteinases, and myeloperoxidase inhibitors. Pharmacological manipulation of the various pathways involved in the process of neutrophil recruitment and activation could allow for successful control and stabilization of HS lesions and the remission of active, severe flares.

DZ2002 alleviates psoriasis-like skin lesions via differentially regulating methylation of GATA3 and LCN2 promoters

Psoriasis is the most prevalent inflammatory skin disorders, affecting 1-3% of the worldwide population. We previously reported that topical application of methyl 4-(adenin-9-yl)-2-hydroxybutanoate (DZ2002), a reversible S-adenosyl-l-homocysteine hydrolase (SAHH) inhibitor, was a viable treatment in murine psoriatic skin inflammation. In current study, we further explored the mechanisms of DZ2002 on keratinocyte dysfunction and skin infiltration, the key pathogenic events in psoriasis. We conducted genome-wide DNA methylation analysis in skin tissue from imiquimod (IMQ)-induced psoriatic and normal mice, demonstrated that topical administration of DZ2002 directly rectified aberrant DNA methylation pattern in epidermis and dermis of psoriatic skin lesion. Especially, DZ2002 differentially regulated DNA methylation of GATA3 and LCN2 promoters, which maintained keratinocytes differentiation and reduced inflammatory infiltration in psoriatic skin respectively. In vitro studies in TNF-α/IFN-γ-elicited HaCaT manifested that DZ2002 treatment rectified compromised keratinocyte differentiation via GATA3 enhancement and abated chemokine expression by reducing LCN2 production under inflammatory stimulation. Chemotaxis assays conducted on dHL-60 cells confirmed that suppression of LCN2 expression by DZ2002 was accompanied by CXCR1 and CXCR2 downregulation, and contributed to the inhibition of CXCL8-driven neutrophils migration. In conclusion, therapeutic benefits of DZ2002 are achieved through differentially regulating DNA methylation of GATA3 and LCN2 promoters in psoriatic skin lesion, which efficiently interrupt the pathogenic interplay between keratinocytes and infiltrating immune cells, thus maintains epidermal keratinocytes differentiation and prevents dermal immune infiltration in psoriatic skin.

Antifibrotic effect of novel neutrophil gelatinase-associated lipocalin inhibitors in cardiac and renal disease models

Neutrophil gelatinase-associated lipocalin (NGAL) is involved in cardiovascular and renal diseases. Gene inactivation of NGAL blunts the pathophysiological consequences of cardiovascular and renal damage. We aimed to design chemical NGAL inhibitors and investigate its effects in experimental models of myocardial infarction (MI) and chronic kidney disease induced by 5/6 nephrectomy (CKD) on respectively 8–12 weeks old C57Bl6/j and FVB/N male mice. Among the 32 NGAL inhibitors tested, GPZ614741 and GPZ058225 fully blocked NGAL-induced inflammatory and profibrotic markers in human cardiac fibroblasts and primary mouse kidney fibroblasts. The administration of GPZ614741 (100 mg/kg/day) for three months, was able to improve cardiac function in MI mice and reduced myocardial fibrosis and inflammation. The administration of GPZ614741 (100 mg/kg/day) for two months resulting to no renal function improvement but prevented the increase in blood pressure, renal tubulointerstitial fibrosis and profibrotic marker expression in CKD mice. In conclusion, we have identified new compounds with potent inhibitory activity on NGAL-profibrotic and pro-inflammatory effects. GPZ614741 prevented interstitial fibrosis and dysfunction associated with MI, as well as tubulointerstitial fibrosis in a CKD model. These inhibitors could be used for other diseases that involve NGAL, such as cancer or metabolic diseases, creating new therapeutic options.

Molecular Aspects of Pruritus Pathogenesis in Psoriasis

Psoriasis is a chronic, systemic inflammatory disease with a genetic background that involves almost 3% of the general population worldwide. Approximately, 70–90% of patients with psoriasis suffer from pruritus, an unpleasant sensation that provokes a desire to scratch. Despite the enormous progress in understanding the mechanisms that cause psoriasis, the pathogenesis of psoriasis-related pruritus still remains unclear. In order to improve patients’ quality of life, development of more effective and safer antipruritic therapies is necessary. In turn to make it possible, better understanding of complexed and multifactorial pathogenesis of this symptom is needed. In this article we have systematized the current knowledge about pruritus origin in psoriasis.

Adipokines in the Skin and in Dermatological Diseases

Adipokines are the primary mediators of adipose tissue-induced and regulated systemic inflammatory diseases; however, recent findings revealed that serum levels of various adipokines correlate also with the onset and the severity of dermatological diseases. Importantly, further data confirmed that the skin serves not only as a target for adipokine signaling, but may serve as a source too. In this review, we aim to provide a complex overview on how adipokines may integrate into the (patho) physiological conditions of the skin by introducing the cell types, such as keratinocytes, fibroblasts, and sebocytes, which are known to produce adipokines as well as the signals that target them. Moreover, we discuss data from in vivo and in vitro murine and human studies as well as genetic data on how adipokines may contribute to various aspects of the homeostasis of the skin, e.g., melanogenesis, hair growth, or wound healing, just as to the pathogenesis of dermatological diseases such as psoriasis, atopic dermatitis, acne, rosacea, and melanoma.