Analysis of the mucosal chemokines CCL28, CXCL14, and CXCL17 in dry eye disease: An in vitro and clinical investigation

Mucosal chemokines have antimicrobial properties and play an important role in mucosal immunity. However, little is known about their expression on the ocular surface. This study aimed to analyze the expression of the mucosal chemokines CCL28, CXCL14 and CXCL17 in corneal and conjunctival epithelial cells under in vitro dry eye (DE) conditions, and in conjunctival samples from healthy subjects and DE patients. Human corneal epithelial cells (HCE) and immortalized human conjunctival epithelial cells (IM-HConEpiC) were incubated under hyperosmolar (400-500 mOsM) or inflammatory (TNF-α 25 ng/mL) conditions for 6 h and 24 h to measure CCL28, CXCL14, and CXCL17 gene expression by RT-PCR and their secretion by immunobead-based analysis (CCL28, CXCL14) and ELISA (CXCL17). Additionally, twenty-seven DE patients and 13 healthy subjects were included in this study. DE-related questionnaires (OSDI, mSIDEQ and NRS) evaluated symptomatology. Ocular surface integrity was assessed using vital staining. Tactile sensitivity was measured with Cochet-Bonnet esthesiometer, and mechanic and thermal (heat and cold) sensitivity using Belmonte's non-contact esthesiometer. Subbasal nerve plexus and dendritic cell density were analyzed by in vivo confocal microscopy. Conjunctival cells from participants were collected by impression cytology to measure mucosal chemokines gene expression by RT-PCR. Our results showed that HCE and IM-HConEpiC cells increased CCL28, CXCL14, and CXCL17 secretion under hyperosmolar conditions. The gene expression of CCL28 was significantly upregulated in conjunctival samples from DE patients. CCL28 expression correlated positively with symptomatology, corneal staining, heat sensitivity threshold, and dendritic cell density. CXCL14 expression correlated positively with age, ocular pain, conjunctival staining, tactile sensitivity, and image reflectivity. CXCL17 expression correlated positively with corneal staining. These results suggest that corneal and conjunctival epithelial cells could be a source of CCL28, CXCL14, and CXCL17 on the ocular surface and that CCL28 might be involved in DE pathogenesis.

The Chemokine CXCL14 as a Potential Immunotherapeutic Agent for Cancer Therapy

There is great enthusiasm toward the development of novel immunotherapies for the treatment of cancer, and given their roles in immune system regulation, chemokines stand out as promising candidates for use in new cancer therapies. Many previous studies have shown how chemokine signaling pathways could be targeted to halt cancer progression. We and others have revealed that the chemokine CXCL14 promotes antitumor immune responses, suggesting that CXCL14 may be effective for cancer immunotherapy. However, it is still unknown what mechanism governs CXCL14-mediated antitumor activity, how to deliver CXCL14, what dose to apply, and what combinations with existing therapy may boost antitumor immune responses in cancer patients. Here, we provide updates on the role of CXCL14 in cancer progression and discuss the potential development and application of CXCL14 as an immunotherapeutic agent.

CXCL14 as a Key Regulator of Neuronal Development: Insights from Its Receptor and Multi-Omics Analysis

CXCL14 is not only involved in the immune process but is also closely related to neurodevelopment according to its molecular evolution. However, what role it plays in neurodevelopment remains unclear. In the present research, we found that, by crossbreeding CXCL14+/- and CXCL14-/- mice, the number of CXCL14-/- mice in their offspring was lower than the Mendelian frequency; CXCL14-/- mice had significantly fewer neurons in the external pyramidal layer of cortex than CXCL14+/- mice; and CXCL14 may be involved in synaptic plasticity, neuron projection, and chemical synaptic transmission based on analysis of human clinical transcriptome data. The expression of CXCL14 was highest at day 14.5 in the embryonic phase and after birth in the mRNA and protein levels. Therefore, we hypothesized that CXCL14 promotes the development of neurons in the somatic layer of the pyramidal cells of mice cortex on embryonic day 14.5. In order to further explore its mechanism, CXCR4 and CXCR7 were suggested as receptors by Membrane-Anchored Ligand and Receptor Yeast Two-Hybrid technology. Through metabolomic techniques, we inferred that CXCL14 promotes the development of neurons by regulating fatty acid anabolism and glycerophospholipid anabolism.

Biomarker discovery in acetaminophen hepatotoxicity: leveraging single-cell transcriptomics and mechanistic insight

INTRODUCTION

Acetaminophen (APAP) overdose is the leading cause of drug-induced liver injury and can cause a rapid progression to acute liver failure (ALF). Therefore, the identification of prognostic biomarkers to determine which patients will require a liver transplant is critical for APAP-induced ALF.

AREAS COVERED

We begin by relating the mechanistic investigations in mouse models of APAP hepatotoxicity to the human APAP overdose pathophysiology. We draw insights from the established sequence of molecular events in mice to understand the progression of events in the APAP overdose patient. Through this mechanistic understanding, several new biomarkers, such as CXCL14, have recently been evaluated. We also explore how single-cell RNA sequencing, spatial transcriptomics, and other omics approaches have been leveraged for identifying novel biomarkers and how these approaches will continue to push the field of biomarker discovery forward.

EXPERT OPINION

Recent investigations have elucidated several new biomarkers or combination of markers such as CXCL14, a regenerative miRNA signature, a cell death miRNA signature, hepcidin, LDH, CPS1, and FABP1. While these biomarkers are promising, they all require further validation. Larger cohort studies analyzing these new biomarkers in the same patient samples, while adding these candidate biomarkers to prognostic models will further support their clinical utility.

Melatonin Inhibits Testosterone Synthesis in Rooster Leydig Cells by Targeting CXCL14 through miR-7481-3p

Melatonin has been proved to be involved in testosterone synthesis, but whether melatonin participates in testosterone synthesis by regulating miRNA in Leydig cells is still unclear. The purpose of this study is to clarify the mechanism of melatonin on Leydig cells testosterone synthesis from the perspective of miRNA. Our results showed that melatonin could significantly inhibit testosterone synthesis in rooster Leydig cells. miR-7481-3p and CXCL14 were selected as the target of melatonin based on RNA-seq and miRNA sequencing. The results of dual-luciferase reporter assays showed that miR-7481-3p targeted the 3'-UTR of CXCL14. The overexpression of miR-7481-3p significantly inhibited the expression of CXCL14 and restored the inhibitory role of melatonin testosterone synthesis and the expression of StAR, CYP11A1, and 3β-HSD in rooster Leydig cells. Similarly, interference with CXCL14 could reverse the inhibitory effect of melatonin on the level of testosterone synthesis and the expression of StAR, CYP11A1, and 3β-HSD in rooster Leydig cells. The RNA-seq results showed that melatonin could activate the PI3K/AKT signal pathway. Interference with CXCL14 significantly inhibited the phosphorylation level of PI3K and AKT, and the inhibited PI3K/AKT signal pathway could reverse the inhibitory effect of CXCL14 on testosterone synthesis and the expression of StAR, CYP11A1 and 3β-HSD in rooster Leydig cells. Our results indicated that melatonin inhibits testosterone synthesis by targeting miR-7481-3p/CXCL14 and inhibiting the PI3K/AKT pathway.

Data Mining Suggests That CXCL14 Gene Silencing in Colon Cancer Is Due to Promoter Methylation

CXCL14 is one of the most evolutionarily conserved members of the chemokine family and is constitutionally expressed in multiple organs, suggesting that it is involved in the homeostasis maintenance of the system. CXCL14 is highly expressed in colon epithelial cells and shows obvious gene silencing in clinical colon cancer samples, suggesting that its silencing is related to the immune escape of cancer cells. In this paper, we analyzed the expression profiles of multiple human clinical colon cancer datasets and mouse colon cancer models to reveal the variation trend of CXCL14 expression during colitis, colon polyps, primary colon cancer, and liver metastases. The relationship between CXCL14 gene silencing and promoter hypermethylation was revealed through the colorectal carcinoma methylation database. The results suggest that CXCL14 is a tumor suppressor gene in colorectal carcinoma which is activated first and then silenced during the process of tumor occurrence and deterioration. Promoter hypermethylation is the main cause of CXCL14 silencing. The methylation level of CXCL14 is correlated with the anatomic site of tumor occurrence, positively correlated with patient age, and associated with prognosis. Reversing the hypermethylation of CXCL14 may be an epigenetic therapy for colon cancer.

Fibroblast-derived CXCL14 aggravates crystalline silica-induced pulmonary fibrosis by mediating polarization and recruitment of interstitial macrophages

Exposure to crystalline silica (CS) particles in worksites and dwellings can lead to silicosis due to excessive fibroblast activation. Considering their immuno-regulatory activities, the contribution of pulmonary fibroblasts in the progression of silicosis has not been thoroughly characterized. Here, we demonstrate that exposure of the lung to CS particles leads to the upregulation of fibroblast-derived C-X-C motif chemokine ligand 14 (CXCL14). By employing an in vitro co-culture system, we demonstrated activated fibroblasts recruited bone marrow-derived macrophages (BMDMs) and favored alternative macrophage polarization (M2) mediated by CXCL14. Furthermore, in vivo studies echoed that systemic CXCL14 neutralizing or fibroblast-specific Cxcl14 knockout proved CXCL14 was indispensable for the recruitment and phenotype alteration of lung macrophages, especially interstitial macrophages (IMs), under stimulation by CS particles. Mechanistically, we showed that GLI2 and p21-mediated cellular senescence were mediators of CXCL14 production following CS exposure. Accordingly, GLI2 blockage and countering cellular senescence by reviving PINK1-mediated mitophagy may be efficient strategies to reduce CXCL14 expression in activated fibroblasts during silicosis. Our findings emphasize the immuno-regulatory function of fibroblasts in silicosis via CXCL14, providing intervention targets for CS-induced pulmonary fibrosis.

Bovine C-X-C Motif Chemokine Ligand 14 Expression Is Regulated by Alternative Polyadenylation and MicroRNAs

Alternative polyadenylation (APA), including APA that occurs only in the 3' UTR (3' UTR-APA), is an important post-transcriptional regulatory mechanism that leads to distinct 3' UTRs for some genes, increasing the complexity of the transcriptome. The post-transcriptional events regulating the expression of bovine, the C-X-C motif chemokine ligand 14 (CXCL14) gene, remains largely unknown. Here, we find that the bovine CXCL14 gene produces two different lengths of mRNA isoforms due to 3' UTR-APA, and the short and long 3' UTR is 126 bp and 1155 bp, respectively. We found that the expression level of the short isoform was significantly higher than that of the long isoform by luciferase assays and overexpression of different CXCL14 3' UTR-APA isoforms. Moreover, using luciferase assay and site-directed mutagenesis experiments, the results showed that the long CXCL14 3' UTR-APA isoform is downregulated by miR-17-5p, miR-150, and miR-217. However, because the short isoform lacks the true target of miR-17-5p, miR-150, and miR-217 in its 3' UTR and thus escapes the inhibitory effect of these microRNAs, its expression level is significantly higher than that of the long isoform. Finally, we demonstrate that the short CXCL14 3' UTR-APA isoform promotes preadipocyte proliferation by cell counting kit 8 (CCK8) assays. Collectively, our results show that the CXCL14 gene is post-transcriptionally regulated through APA and microRNAs.

Yak-Derived CXCL14 Activates the Pro-Inflammatory Response of Macrophages and Inhibits the Proliferation and Migration of HepG2

CXCL14 (C-X-C motif chemokine ligand 14) is an important chemokine involved in infection and immunity and plays an important role in a variety of immune-related diseases. The 446 bp cDNA sequence of the CXCL14 gene in yaks was obtained. Additionally, the prokaryotic expression vector of the CXCL14 protein with a molecular weight of 27 kDa was successfully constructed and expressed. The proliferation activities and migration abilities of spleen macrophages were significantly inhibited after treatment with the CXCL14 protein at different concentrations (1, 10 and 20 μg/mL) (p < 0.05). Furthermore, the expressions of pro-inflammatory cytokines interleukin 1 beta (IL-1β), interleukin 6 (IL6), interleukin 8 (IL8) and interferon-α (TNF-α) were significantly increased (p < 0.05), but the expression of anti-inflammatory factor interleukin 10 (IL10) was significantly decreased (p < 0.05). The contents of inflammatory factors in the supernatant of cells were detected using ELISA, and it was also found that the contents of TNF-α, IL6 and cytochrome c oxidase subunit II (COX2) were significantly increased under different CXCL14 protein concentrations (p < 0.05). Finally, the exogenous addition of CXCL14 inhibited the activity, clonal formation and migration of hepatoma cells (HepG2). Additionally, after HepG2 cells were treated with 20 μg/mL CXCL14 protein for 12 h, 24 h and 36 h, the expression levels of BCL2 homologous antagonist/killer (BAK) and the BCL2-associated X apoptosis regulator (BAX) were increased to varying degrees, while the expression levels of hypoxia-inducible factor 1 subunit alpha (HIF1A), the mechanistic target of rapamycin kinase (mTOR) and cyclin-dependent kinase 1 (CDK1) genes decreased compared to the control group. In conclusion, the CXCL14 protein can inhibit the proliferation and migration of HepG2 cells by inducing the expression of macrophage pro-inflammatory factors and activating apoptosis-related genes to exert innate immunity. These results are helpful to further study the function of the CXCL14 protein and provide research data for the innate immune mechanism of yaks under harsh plateau environments.

Comprehensive analysis of CXCL14 uncovers its role during liver metastasis in colon cancer

BACKGROUND

The most common cause of death for colon cancer patients is liver metastasis.

METHODS

All the data enrolled in this study were downloaded from two public databases, The Cancer Genome Atlas Program, the TCGA-COAD project and Gene Expression Omnibus, GSE41258 project. All the analysis was performed in R software.

RESULTS

In our study, we systematically explored the molecules involved in the liver metastasis process of colon cancer. The biological role of these molecules was identified through the GO and KEGG analysis. Moreover, we identified that the molecules SERPINA3, SERPINA1, MMP3, ALDH1A3, PBK and CXCL14 were the independent factors for patients survival. The CXCL14 was selected for further analysis for its most significant P value. Single-cell analysis showed that the CXCL14 was mainly expressed in the fibroblasts. Meanwhile, the biological role of fibroblasts in the colon cancer microenvironment was investigated. Further, the clinical role of CXCL14 in colon cancer was also explored. The result showed that the CXCL14 is a protective factor against colon cancer independent of other clinical parameters like age, gender, clinical stage, and TNM classifications. Then, biological enrichment analysis indicated that the CXCL14 is predominantly involved in the activating of the WNT/β/catenin pathway, pancreas beta cells, peroxisome and bile acid metabolism. Immune infiltration analysis showed that for the patients with high CXCL14 levels, the plasma B cells, CD8 + T cells, neutrophil and NK cells might infiltrate more, in contrast to B cells, monocyte and macrophages. Furthermore, we found that the patients with low CXCL14 expression might be more sensitive to etoposide, rapamycin and sunitinib.

CONCLUSIONS

Our result could improve the understanding of the liver metastasis process in colon cancer. Also, CXCL14 was identified as an underlying therapeutic target for colon cancer.

Significant elevated CXCL14 and decreased IL-39 levels in patients with tuberculosis

To explore the serum levels of IL-39, CXCL14, and IL-19 in patients with tuberculosis (TB) along with their clinical significances and their concentration changes in macrophages after Bacille Calmette-Guérin vaccine (BCG) or Mycobacterium tuberculosis (M. tb) H37Rv stimulation in vitro. The serum levels of IL-39, CXCL14, and IL-19 of 38 TB patients, and 20 healthy staff members were measured by enzyme-linked immunosorbent assay. Moreover, the levels of IL-19, CXCL14, and IL-39 in cultured THP-1 macrophages were detected at 12, 24, and 48 h after stimulation with BCG or M. tb H37Rv strains. It was found the serum level of IL-39 was significantly reduced and CXCL14 was remarkably elevated in TB patients. In vitro, at 48 h after stimulation, IL-39 level of cultured THP-1 macrophages in the H37Rv group was significantly lower than that in the BCG and control groups, and the CXCL14 level of cultured THP-1 macrophages in the H37Rv stimulation group was remarkably higher than that in the control group. Therefore, IL-39 and CXCL14 may be involved the pathogenesis of TB, and serum IL-39 and CXCL14 could potentially serve as a new biomarker of TB.

1,5-AG suppresses pro-inflammatory polarization of macrophages and promotes the survival of B-ALL in vitro by upregulating CXCL14

B-lineage acute lymphoblastic leukemia (B-ALL) is one of the most common malignancies in children. Despite advances in treatment, the role of the tumor microenvironment in B-ALL remains poorly understood. Among the key components of the immune microenvironment, macrophages play a critical role in the progression of the disease. However, recent research has suggested that abnormal metabolites may influence the function of macrophages, altering the immune microenvironment and promoting tumor growth. Our previous non-targeted metabolomic detection revealed that the metabolite 1,5-anhydroglucitol (1,5-AG) level in the peripheral blood of children newly diagnosed with B-ALL was significantly elevated. Except for its direct influence on leukemia cells, the effect of 1,5-AG on macrophages is still unclear. Herein, we demonstrated new potential therapeutic targets by focusing on the effect of 1,5-AG on macrophages. We used polarization-induced macrophages to determine how 1,5-AG acted on M1-like polarization and screened out the target gene CXCL14 via transcriptome sequencing. Furthermore, we constructed CXCL14 knocked-down macrophages and a macrophage-leukemia cell coculture model to validate the interaction between macrophages and leukemia cells. We discovered that 1,5-AG upregulated the CXCL14 expression, thereby inhibiting M1-like polarization. CXCL14 knockdown restored the M1-like polarization of macrophages and induced leukemia cells apoptosis in the coculture model. Our findings offer new possibilities for the genetic engineering of human macrophages to rehabilitate their immune activity against B-ALL in cancer immunotherapy.

Geniposide ameliorates atherosclerosis by regulating macrophage polarization via perivascular adipocyte-derived CXCL14

ETHNOPHARMACOLOGICAL RELEVANCE

Gardenia jasminoides Ellis is a traditional Chinese medicine that has been used for treatment of various diseases, including atherosclerosis by clearing heat and detoxication. Geniposide is considered as the effective compounds responsible for the therapeutic efficacy of Gardenia jasminoides Ellis against atherosclerosis.

AIM OF THE STUDY

To investigate the effect of geniposide on atherosclerosis burden and plaque macrophage polarization, with focus on its potential impact on CXCL14 expression by perivascular adipose tissue (PVAT).

MATERIALS AND METHODS

ApoE^-/- mice fed a western diet (WD) were used to model atherosclerosis. In vitro cultures of mouse 3T3-L1 preadipocytes and RAW264.7 macrophages were used for molecular assays.

RESULTS

The results revealed that geniposide treatment reduced atherosclerotic lesions in ApoE^-/- mice, and this effect was correlated with increased M2 and decreased M1 polarization of plaque macrophages. Of note, geniposide increased the expression of CXCL14 in PVAT, and both the anti-atherosclerotic effect of geniposide, as well as its regulatory influence on macrophage polarization, were abrogated upon in vivo CXCL14 knockdown. In line with these findings, exposure to conditioned medium from geniposide-treated 3T3-L1 adipocytes (or to recombinant CXCL14 protein) enhanced M2 polarization in interleukin-4 (IL-4) treated RAW264.7 macrophages, and this effect was negated after CXCL14 silencing in 3T3-L1 cells.

CONCLUSION

In summary, our findings suggest that geniposide protects ApoE^-/- mice against WD-induced atherosclerosis by inducing M2 polarization of plaque macrophages via enhanced expression of CXCL14 in PVAT. These data provide novel insights into PVAT paracrine function in atherosclerosis and reaffirm geniposide as a therapeutic drug candidate for atherosclerosis treatment.

BACE1 regulates expression of Clusterin in astrocytes for enhancing clearance of β-amyloid peptides

BACKGROUND

Abnormal accumulation of amyloid beta peptide (Aβ) in the brain induces a cascade of pathological changes in Alzheimer's disease (AD), and inhibiting BACE1, which is required for Aβ generation, is therefore being explored for the treatment of AD by reducing Aβ accumulation. As Bace1 knockout mice exhibit increased number of reactive astrocytes and AD brains have reactive astrocytes that surround amyloid plaques, we investigated the role of BACE1 in astrocytes and determined whether BACE1 regulates astrocytic functions.

METHODS

We conducted unbiased single cell RNA-seq (scRNA-seq) using purified astrocytes from Bace1 KO mice and wild type control littermates. Similar scRNA-seq was also conducted using AD mice with conditional deletion of Bace1 in the adult stage (5xFAD;Bace1^fl/fl;UBC-creER compared to 5xFAD;Bace1^fl/fl controls). We compared the transcriptomes of astrocyte and reactive astrocyte clusters and identified several differentially expressed genes, which were further validated using Bace1 KO astrocyte cultures. Mice with astrocyte-specific Bace1 knockout in 5xFAD background were used to compare amyloid deposition. Mechanistic studies using cultured astrocytes were used to identify BACE1 substrates for changes in gene expression and signaling activity.

RESULTS

Among altered genes, Clusterin (Clu) and Cxcl14 were significantly upregulated and validated by measuring protein levels. Moreover, BACE1 deficiency enhanced both astrocytic Aβ uptake and degradation, and this effect was significantly attenuated by siRNA knockdown of Clu. Mechanistic study suggests that BACE1 deficiency abolishes cleavage of astrocytic insulin receptors (IR), and this may enhance expression of Clu and Cxcl14. Acutely isolated astrocytes from astrocyte-specific knockout of Bace1 mice (Bace1 ^fl/fl;Gfap-cre) show similar increases in CLU and IR. Furthermore, astrocyte-specific knockout of Bace1 in a 5xFAD background resulted in a significant attenuation in cortical Aβ plaque load through enhanced clearance.

CONCLUSION

Together, our study suggests that BACE1 in astrocytes regulates expression of Clu and Cxcl14, likely via the control of insulin receptor pathway, and inhibition of astrocytic BACE1 is a potential alternative strategy for enhancing Aβ clearance.

CXCL14-like immunoreactivity in somatostatin-producing cells of the Japanese quail (Coturnix japonica) pancreas

This study examines chemokine CXCL14-like peptide distribution in the Japanese quail (Coturnix japonica) pancreas using a specific anti-human CXCL14 antibody. CXCL14-immunoreactive cells were observed in the pancreatic islet peripheral region. The staining was abolished after pre-absorbing the antibody with recombinant human CXCL14. CXCL14-immunoreactive cells were immuno-positive for somatostatin, but not glucagon and insulin. CXCL14 secreted from somatostatin-producing cells might participate in insulin secretion modulation together with somatostatin. In addition, CXCL14 might participate in glucose homeostasis in co-operation with somatostatin and growth hormone.

Galactomyces Ferment Filtrate Potentiates an Anti-Inflammaging System in Keratinocytes

Skincare products play a crucial role in preventing the dry skin induced by various causes. Certain ingredients can help to improve the efficacy of skincare products. Galactomyces ferment filtrate (GFF) is such a functional ingredient. Its use originated from the empirical observation that the hands of sake brewers who deal with yeast fermentation retain a beautiful and youthful appearance. Consequently, skincare products based on GFF are widely used throughout the world. Recent studies have demonstrated that GFF activates an aryl hydrocarbon receptor (AHR) and upregulates the expression of filaggrin, a pivotal endogenous source of natural moisturizing factors, in epidermal keratinocytes. It also activates nuclear factor erythroid-2-related factor 2 (NRF2), the antioxidative master transcription factor, and exhibits potent antioxidative activity against oxidative stress induced by ultraviolet irradiation and proinflammatory cytokines, which also accelerate inflammaging. GFF-mediated NRF2 activation downregulates the expression of CDKN2A, which is known to be overexpressed in senescent keratinocytes. Moreover, GFF enhances epidermal terminal differentiation by upregulating the expression of caspase-14, claudin-1, and claudin-4. It also promotes the synthesis of the antiinflammatory cytokine IL-37 and downregulates the expression of proallergic cytokine IL-33 in keratinocytes. In addition, GFF downregulates the expression of the CXCL14 and IL6R genes, which are involved in inflammaging. These beneficial properties might underpin the potent barrier-protecting and anti-inflammaging effects of GFF-containing skin formulae.

Effect of chemokine CXCL14 on in vitro angiogenesis of human hepatocellular carcinoma cells

The study was designed to investigate the effect of chemokine CXCL14 on in vitro angiogenesis of human hepatocellular carcinoma (HCC) cells. CXCL14 mRNA expression in HCC tissue samples and adjacent tissue samples was detected by quantitative reverse transcription polymerase chain reaction (qRT-PCR). CXCL14 mRNA and protein expression in human normal hepatocyte HL-7702 and HCC cell line HepG2 were detected by qRT-PCR and western blot. In HepG2 cell line, the expression of vascular endothelial growth factor (VEGF) was detected by enzyme-linked immunosorbent assay method, cell viability was detected by CCK-8, cell proliferation was detected by colony formation assay, and cell migration as well as invasion ability was detected by Transwell assay. Moreover, human umbilical vein endothelial cell (HUVEC) tube formation assay was carried out to determine the cell ability of angiogenesis. Results showed that the overexpression of CXCL14 could inhibit angiogenesis, proliferation, migration, and invasion abilities of HCC cells.Highlights CXCL14 is lowly expressed in hepatocellular carcinoma tissues and cells. CXCL14 overexpression inhibits the angiogenesis of hepatocellular carcinoma cells. CXCL14 overexpression inhibits proliferation, invasion, and migration of hepatocellular carcinoma cells.

CXCL14 exacerbates seizures by inhibiting GABA metabolism in epileptic mice

OBJECTIVE

Epilepsy is a common central nervous system disorder with pathological mechanisms including inflammation, ion channel impairment, and neurotransmitter imbalance. Despite the rapid development of current anti-epileptic drugs, epilepsy is not well controlled, so there is still a need for research on the mechanisms and new drug targets for epilepsy. CXCL14 is a member of the CXC family of chemokines, and its receptor is currently unknown. Chemokines are the third major communication mediators in the central nervous system and play a role in many diseases. Therefore, we explore the expression of CXCL14 in epilepsy and its possible mechanisms.

MATERIALS AND METHODS

We chose the kainic acid (KA) mouse model as the epilepsy model, and studied the expression of CXCL14 in this model by western blot. Subsequently, after knocking down CXCL14, we explored the effect of CXCL14 on seizures by electrophysiology and FJB (Fluoro-Jade B) staining. Western blot and ELISA were used to explore the possible mechanism of CXCL14 affecting seizures.

RESULTS

CXCL14 expression gradually increased after a seizure until it peaked at 72 hours and then gradually decreased again. The knockdown of CXCL14 resulted in prolonged seizure latency, decreased seizure grade, and reduced degenerative necrosis of neurons in mice. Levels of GABA (γ-aminobutyric acid), GAD67 (glutamate decarboxylase 67) and GABA_A receptor (γ-aminobutyric acid A receptor) were increased.

CONCLUSION

Our results suggest that CXCL14 expression is increased after seizures and may exacerbate seizures by regulating GABA metabolism. Based on this, CXCL14 could be a new target for epilepsy treatment and antiepileptic drug development.

Elevated CXCL14 in Induced Sputum Was Associated with Eosinophilic Inflammation and Airway Obstruction in Patients with Asthma

INTRODUCTION

CXCL14 involved in inflammatory processes was upregulated in the asthma expression profile datasets in our pilot study. However, the expression of CXCL14 in induced sputum and its potential clinical role in asthma were poorly reported.

OBJECTIVE

We sought to detect CXCL14 expression in airway epithelium and induced sputum cells of asthma and explore its potential clinical implications.

METHODS

The expression of CXCL14 in asthma was analyzed using R software based on multiple microarray datasets, including GSE43696, GSE63142, GSE67940, and GSE76262. Subsequent verification of the CXCL14 expression pattern in induced sputum and bronchial epithelium cells was performed by qRT-PCR and ELISA. Besides, the correlations between CXCL14 and eosinophilic inflammation indicators (FeNO, EOS#, and IgE), Th2 signature genes (SERPINB2, POSTN, and CLCA1), inflammatory cytokines (IL-4, IL-5, IL-10, IL-13, IL-25, IL-33, TSLP, IL-8, IL-17A, IFN-γ, and IL-2), and airway obstruction indicators (pulmonary function and mucin secretion) were further explored.

RESULTS

The expression of CXCL14 in epithelium and sputum cells was upregulated in asthma and positively correlated with clinical eosinophilic indicators. The protein levels of CXCL14 were positively associated with Th2 signature genes (SERPINB2, POSTN, and CLCA1) and Th2 cytokines (IL-4, IL-5, IL-10, IL-13, IL-25, IL-33, and TSLP). Increased expression of CXCL14 was also observed in BEAS-2B cells stimulated by the cytokine IL-4. Furthermore, the expression of CXCL14 was positively correlated with MUC5AC secretion and negatively associated with pulmonary function.

CONCLUSIONS

Upregulated CXCL14 in asthma was positively correlated with inflammatory indicators and negatively correlated with pulmonary function, which indicated that upregulated CXCL14 might act as a pathogenic gene through involvement in Th2 inflammation in asthma.

CXCL14 Protects Against Polymicrobial Sepsis by Enhancing Antibacterial Functions of Macrophages

Rapid and effective control of bacterial infection is critical for the treatment of bacterial sepsis. CXCL14 is an important chemokine involved in infection and immunity, which can bind to CXCR4. However, the contribution of CXCL14/CXCR4 chemokine axis to bacterial clearance in sepsis remains unknown. Here the impact of CXCL14/CXCR4 blockade or CXCL14 administration on sepsis was assessed using murine and cell models, as well as human samples. CXCL14 protein levels were elevated in mice after cecal ligation and puncture (CLP)-induced sepsis. In vivo, CXCL14 blockade using anti-CXCL14 antibody or CXCL14 knockdown by adeno-associated virus carrying-CXCL14 shRNA significantly increased mortality and bacterial burden, which was paralleled by significantly decreased macrophage influx and M2 macrophage polarization at the site of infection after CLP. Therapeutic administration of CXCL14 improved mortality and bacterial clearance after CLP in a CXCR4-dependent manner, and macrophages, but not neutrophils, were important for the protective effect of CXCL14 in sepsis. In vitro, CXCL14 directly enhanced bacterial phagocytosis and killing of macrophages, and it also increased phagosome formation and reactive oxygen species (ROS) production in macrophages. Furthermore, inhibiting the activation of PI3K/Akt and NF-κB signaling pathways, but not STAT1, abrogated the enhanced antibacterial effects of CXCL14 on macrophages. Finally, circulating CXCL14 levels were significantly up-regulated in the patients with sepsis. CXCL14 could enhance bacterial phagocytosis and killing in human monocyte-derived macrophages, which was dependent on CXCR4. Therefore, our results indicate a previously undescribed role of CXCL14/CXCR4 axis and suggest CXCL14 as a potential adjunct therapy in bacterial sepsis.

Circadian protection against bacterial skin infection by epidermal CXCL14-mediated innate immunity

The epidermis is the outermost layer of the skin and the body's primary barrier to external pathogens; however, the early epidermal immune response remains to be mechanistically understood. We show that the chemokine CXCL14, produced by epidermal keratinocytes, exhibits robust circadian fluctuations and initiates innate immunity. Clearance of the skin pathogen Staphylococcus aureus in nocturnal mice was associated with CXCL14 expression, which was high during subjective daytime and low at night. In contrast, in marmosets, a diurnal primate, circadian CXCL14 expression was reversed. Rhythmically expressed CXCL14 binds to S. aureus DNA and induces inflammatory cytokine production by activating Toll-like receptor (TLR)9-dependent innate pathways in dendritic cells and macrophages underneath the epidermis. CXCL14 also promoted phagocytosis by macrophages in a TLR9-independent manner. These data indicate that circadian production of the epidermal chemokine CXCL14 rhythmically suppresses skin bacterial proliferation in mammals by activating the innate immune system.

Integrated analysis of 14 lymphoma datasets revealed high expression of CXCL14 promotes cell migration in mantle cell lymphoma

Lymphoma is accompanied by the impairment of multiple immune functions. Cytokines play an important role in a variety of immune-related functions and affect the tumor microenvironment. However, the exact regulatory mechanisms between them remain unclear. This study aimed to explore the cytokines expression and function in Hodgkin's lymphoma (HL), diffuse large B-cell lymphoma (DLBCL), and mantle cell lymphoma (MCL). We performed a transcriptome integration analysis of 14 lymphoma datasets including 240 Hodgkin's lymphoma, 891 diffuse large B-cell lymphoma, 216 mantle cell lymphoma, and 64 health samples. The results showed that multiple immune functions and signal pathway damage were shared by all three types of lymphoma, and these functions were related to cytokines. Furthermore, through co-expression network and functional interaction network analysis, we identified CXCL14 as a key regulator and it affects cell chemotaxis and migration functions. The functional experiment showed that CXCL14 knockdown inhibited cell migration in MCL cell lines. This study suggested that high expression of CXCL14 may aggravate MCL via promoting cell migration. Our findings provide novel insights into the biology of this disease and would be helpful for the pathogenesis study and drug discovery of lymphomas.

Dysregulation of CXCL14 promotes malignant phenotypes of esophageal squamous carcinoma cells via regulating SRC and EGFR signaling

The present study was to identify abnormal methylation genes implicated in esophageal squamous cell carcinoma (ESCC). Genomic methylation alterations in ESCC tissues were analyzed using laser-microdissection and whole-genome bisulfite sequencing. CXCL14 promoter was frequently hypermethylated in ESCC tissues. The correlation of CXCL14 hypermethylation status and the mRNA and protein expression levels were validated using nested methylation-specific PCR (nMS-PCR), RNAscope in situ hybridization (RISH) and Western blot. RISH results showed completely negative CXCL14 expression in 34.3% (34/99) ESCC, compared with those in the basal layer cells of normal epithelia. Low expression of CXCL14 was more present in patients with lower differentiation. The anticancer role of CXCL14 has been commonly associated with immune regulation in the literature. Here, we observed by functional analysis that CXCL14 can also act as a tumor suppressor in ESCC cells. 5-Aza-dC treatment suppressed CXCL14 methylation and up-regulated the expression of CXCL14. Ectopic expression of CXCL14 suppressed the proliferation, invasion, tumor growth, and lung metastasis of ESCC cells. Both ectopic expression and induction of CXCL14 with 5-Aza-dC inhibited the activity of SRC, MEK1/2 and STAT3 in ESCC cells, while activated EGFR. Importantly, a combination of CXCL14 expression and SRC or EGFR inhibitor dramatically repressed the proliferation of ESCC cells and the growth of xenografts. Our findings revealed a direct tumor suppressor role of CXCL14, but not through the immune system. The data suggest that for ESCC patients with low level CXCL14, increasing CXCL14 expression combined with inhibition of SRC or EGFR might be a promising therapeutic strategy.

Posterior Cervical Brown Fat and CXCL14 Levels in the First Year of Life: Sex Differences and Association With Adiposity

CONTEXT

Brown adipose tissue (BAT) is particularly abundant in neonates, but its association with measures of adiposity and metabolic health in early infancy is poorly delineated. Besides sustaining nonshivering thermogenesis, BAT secretes brown adipokines that act on systemic metabolism. The chemokine CXCL14 has been identified as a brown adipokine in experimental studies.

OBJECTIVE

To determine the relationships among BAT activity, adiposity, and circulating CXCL14 levels in the first year of life in girls and boys.

METHODS

Indices of fat accretion, circulating endocrine-metabolic parameters and serum CXCL14 levels were assessed longitudinally in a cohort of infants at birth and at 4 and 12 months. BAT activity was estimated using infrared thermography only at age 12 months.The main outcome measures were weight and length Z-scores, total and abdominal fat content (by dual X-ray absorptiometry), BAT activity at the posterior cervical and supraclavicular regions, serum levels of glucose, insulin, insulin-like growth factor-I, high-molecular-weight adiponectin, and CXCL14; CXCL14 transcript levels in neonatal BAT and liver.

RESULTS

Posterior cervical BAT was more active in girls than in boys (P = .02). BAT activity was negatively associated with adiposity parameters only in girls. CXCL14 levels were higher in girls than in boys at age 12 months and correlated positively with the area of active posterior cervical BAT in girls. Neonatal BAT showed high CXCL14 gene expression levels.

CONCLUSION

BAT activity and the levels of CXCL14-a potential surrogate of BAT activity-are sex specific in the first year of life. Posterior cervical BAT activity associates negatively with indices of adiposity only in girls.

Ample dietary fat reduced the risk of primary vesical calculi by inducing macrophages to engulf budding crystals in mice

Although primary vesical calculi is an ancient disease, the mechanism of calculi formation remains unclear. In this study, we established a novel primary vesical calculi model with d,l-choline tartrate in mice. Compared with commonly used melamine and ethylene glycol models, our model was the only approach that induced vesical calculi without causing kidney injury. Previous studies suggest that proteins in the daily diet are the main contributors to the prevention of vesical calculi, yet the effect of fat is overlooked. To assay the relationship of dietary fat with the formation of primary vesical calculi, d,l-choline tartrate-treated mice were fed a high-fat, low-fat, or normal-fat diet. Genetic changes in the mouse bladder were detected with transcriptome analysis. A high-fat diet remarkably reduced the morbidity of primary vesical calculi. Higher fatty acid levels in serum and urine were observed in the high-fat diet group, and more intact epithelia in bladder were observed in the same group compared with the normal- and low-fat diet groups, suggesting the protective effect of fatty acids on bladder epithelia to maintain its normal histological structure. Transcriptome analysis revealed that the macrophage differentiation-related gene C–X–C motif chemokine ligand 14 (Cxcl14) was upregulated in the bladders of high-fat diet-fed mice compared with those of normal- or low-fat diet-fed mice, which was consistent with histological observations. The expression of CXCL14 significantly increased in the bladder in the high-fat diet group. CXCL14 enhanced the recruitment of macrophages to the crystal nucleus and induced the transformation of M2 macrophages, which led to phagocytosis of budding crystals and prevented accumulation of calculi. In human bladder epithelia (HCV-29) cells, high fatty acid supplementation significantly increased the expression of CXCL14. Dietary fat is essential for the maintenance of physiological functions of the bladder and for the prevention of primary vesical calculi, which provides new ideas for the reduction of morbidity of primary vesical calculi.

Proteomic and metabolomic profiling of urine uncovers immune responses in patients with COVID-19

The utility of the urinary proteome in infectious diseases remains unclear. Here, we analyzed the proteome and metabolome of urine and serum samples from patients with COVID-19 and healthy controls. Our data show that urinary proteins effectively classify COVID-19 by severity. We detect 197 cytokines and their receptors in urine, but only 124 in serum using TMT-based proteomics. The decrease in urinary ESCRT complex proteins correlates with active SARS-CoV-2 replication. The downregulation of urinary CXCL14 in severe COVID-19 cases positively correlates with blood lymphocyte counts. Integrative multiomics analysis suggests that innate immune activation and inflammation triggered renal injuries in patients with COVID-19. COVID-19-associated modulation of the urinary proteome offers unique insights into the pathogenesis of this disease. This study demonstrates the added value of including the urinary proteome in a suite of multiomics analytes in evaluating the immune pathobiology and clinical course of COVID-19 and, potentially, other infectious diseases.

Kupffer cells regulate liver recovery through induction of chemokine receptor CXCR2 on hepatocytes after acetaminophen overdose in mice

Acetaminophen (APAP) is a widely used analgesic, but also a main cause of acute liver injury in the United States and many western countries. APAP hepatotoxicity is associated with a sterile inflammatory response as shown by the infiltration of neutrophils and monocytes. While the contribution of the immune cells to promote liver repair have been demonstrated, the direct interactions between macrophages or neutrophils with hepatocytes to help facilitate hepatocyte proliferation and tissue repair remain unclear. The purpose of this study was to investigate the relationship between resident macrophages (Kupffer cells) and hepatocytes with a focus on the chemokine receptor CXCR2. C57BL/6J mice were subjected to an APAP overdose (300 mg/kg) and the role of CXCR2 on hepatocytes was investigated using a selective antagonist, SB225002. In addition, clodronate liposomes were used to deplete Kupffer cells to assess changes in CXCR2 expression. Our data showed that CXCR2 was mainly expressed on hepatocytes and it was induced specifically in hepatocytes around the necrotic area 24 h after APAP treatment. Targeting this receptor using an inhibitor caused a delayed liver recovery. Depletion of Kupffer cells significantly prevented CXCR2 induction on hepatocytes. In vitro and in vivo experiments also demonstrated that Kupffer cells regulate CXCR2 expression and pro-regenerative gene expression in surviving hepatocytes through production of IL-10. Thus, Kupffer cells support the transition of hepatocytes around the area of necrosis to a proliferative state through CXCR2 expression.

CXCL14 facilitates the growth and metastasis of ovarian carcinoma cells via activation of the Wnt/β-catenin signaling pathway

BACKGROUND

There is an urgent need to identify potential targets in anticancer therapy to improve the survival and prognosis of patients with ovarian cancer (OC). Herein, we investigated the functional significance of chemokine (C-X-C motif) ligand 14 (CXCL14) in OC cell growth and epithelial-mesenchymal transition (EMT).

METHODS

qRT PCR and western blotting was used to detect CXCL14 mRNA level and protein expression, respectively. The functional mechanism of CXCL14 in OC was investigated by CCK-8, colony formation and transwell assays. The migration ability of OC cell was determined using wound healing. The protein expressions of CXCL14 and β-catenin in OC tissues were determined by immumohistochemical staining.

RESULTS

We demonstrated that high levels of CXCL14 were associated with a worse prognosis in patients with OC. CXCL14 knockdown considerably restrained the growth, migration and invasion of OC cell in vitro. In contrast, ectopic CXCL14 overexpression yielded the opposite results. Investigations to determine the underlying molecular mechanisms revealed that the Wnt/β-catenin signaling pathway is involved in CXCL14-facilitated OC cell invasiveness.

CONCLUSION

These data collectively demonstrate that CXCL14 contributes to OC cell growth and metastatic potential by regulating the Wnt/β-catenin signaling pathway.

Aberrant ROS Mediate Cell Cycle and Motility in Colorectal Cancer Cells Through an Oncogenic CXCL14 Signaling Pathway

Background: Reactive oxygen species (ROS) act as signal mediators to induce tumorigenesis.

Objective: This study aims to explore whether chemokine CXCL14 is involved in the proliferation and migration of ROS-induced colorectal cancer (CRC) cells.

Methods: The proliferative and migratory capacities of CRC cells treated with or without H₂O₂ were measured by various methods, including the CKK-8 assay, colony formation assay, flow cytometry, wounding healing assay, and migration assay.

Results: The results revealed that H₂O₂ promoted the proliferation and migration of CRC cells by regulating the cell cycle progression and the epithelial to mesenchymal transition (EMT) process. Furthermore, we noted that the expression level of CXCL14 was elevated in both HCT116 cells and SW620 cells treated with H₂O₂. An antioxidant N-Acetyl-l-cysteine (NAC) pretreatment could partially suppress the CXCL14 expression in CRC cells treated with H₂O₂. Next, we constructed CRC cell lines stably expressing CXCL14 (HCT116/CXCL14 and SW620/CXCL14) and CRC cell lines with empty plasmid vectors (HCT116/Control and SW620/Control) separately. We noted that both H₂O₂ treatment and CXCL14 over-expression could up-regulate the expression levels of cell cycle-related and EMT-related proteins. Moreover, the level of phosphorylated ERK (p-ERK) was markedly higher in HCT116/CXCL14 cells when compared with that in HCT116/Control cells. CXCL14-deficiency significantly inhibited the phosphorylation of ERK compared with control (i.e., scrambled shNCs). H₂O₂ treatment could partially restore the expression levels of CXCL14 and p-ERK in HCT116/shCXCL14 cells.

Conclusion: Our studies thus suggest that aberrant ROS may promote colorectal cancer cell proliferation and migration through an oncogenic CXCL14 signaling pathway.

MiR-3188 regulates the proliferation and apoptosis of hepatocellular carcinoma cells by targeting CXCL14

Aim: The study aimed to probe into the functions and mechanisms of miR-3188 in hepatocellular carcinoma (HCC). Materials & methods: Quantitative real-time PCR and western blot were implemented to detect the expressions of miR-3188 and CXCL14 in HCC tissues and cell lines. CCK-8, 5-ethynyl-2'-deoxyuridine and flow cytometry assays were performed to assess cell viability, proliferation and apoptosis. A dual-luciferase reporter assay was conducted to investigate the relationship between miR-3188 and CXCL14. Results: miR-3188 is up-regulated in HCC tissues. MiR-3188 overexpression promoted cell viability and proliferation but inhibited the apoptosis of HCC cells. CXCL14 was proven to be a target of miR-3188, and CXCL14 reversed the effects of miR-3188 on HCC cells. Conclusion: MiR-3188 regulates the growth and apoptosis of HCC cells by targeting CXCL14.

The roles of Y-box-binding protein (YB)-1 and C-X-C motif chemokine ligand 14 (CXCL14) in the progression of prostate cancer via extracellular-signal-regulated kinase (ERK) signaling

The cold-shock protein Y-box-binding protein (YB)-1 regulates the expression of various chemokines and their receptors at the transcriptional level. Expression of the orphan chemokine CXCL14 is repressed by EGF induced signaling. The possible links between EGF-mediated YB-1 and CXCL14 as well as the functions of critical kinase pathways in the progression of prostate cancer have remained unexplored. Here we examined the correlation between YB-1 and CXCL14, and the ERK/AKT/mTOR pathways in prostate cancer. Knockdown of YB-1 decreased cyclinD1 expression with an upregulation of cleaved-PARP in human prostate cancer cells. EGF treatment upregulated phospho-YB-1 expression in a time-dependent manner, while treatment with an ERK inhibitor completely silenced its expression in prostate cancer cells. EGF treatment stimulates CyclinD1 and YB-1 phosphorylation in an ERK-dependent pathway. Positive and negative regulation of YB-1 and CXCL14 was observed after EGF treatment in prostate cancer cells, respectively. EGF rescues cell cycle and apoptosis via the AKT and ERK pathways. Furthermore, YB-1 silencing induces G1 arrest and apoptosis, while knockdown of CXCL14 facilitates cell growth and inhibits apoptosis in prostate cancer cells. YB-1 and CXCL14 were inversely correlated in prostate cancer cells and tissues. A significant association between poor overall survival and High YB-1 expression was observed in human prostate cancer patients. In conclusion, our data reveal the functional relationship between YB-1 and CXCL14 in EGF mediated ERK signaling, and YB-1 expression is a significant prognostic marker to predict prostate cancer.

Identification of tissue-specific expression of CXCL14 in black rockfish (Sebastes schlegelii)

CXCL14 is a chemokine which is orthologous in mammals and fish. CXCL14 has a functional role in different organs, with immunomodulatory functions in mammals, but its expression and function in fish is not well known. Moreover, it shows no effects related to immunity in the central nervous system or the reproductive tract in diverse species. Black rockfish (Sebastes schlegelii) is an economically important fish in Asian countries, whose CXCL14 expression pattern is yet to be understood. In this study, the homology of the CXCL14 amino acid sequence in S. schlegelii was compared with that in other species, including fish. Moreover, in situ hybridization analysis revealed that it was highly expressed in the brain and ovary of S. schlegelii. Taken together, we identified for the first time, the cell-specific expression of CXCL14 in S. schlegelii.

Chemokine CXCL14; a double-edged sword in cancer development

Cancer is a leading cause of death worldwide and imposes a substantial financial burden. Therefore, it is essential to develop cost-effective approaches to inhibit tumor growth and development. The imbalance of cytokines and chemokines play an important role among different mechanisms involved in cancer development. One of the strongly conserved chemokines that is constitutively expressed in skin epithelia is the chemokine CXCL14. As a member of the CXC subfamily of chemokines, CXCL14 is responsible for the infiltration of immune cells, maturation of dendritic cells, upregulation of major histocompatibility complex (MHC)-I expression, and cell mobilization. Moreover, dysregulation of CXCL14 in several cancers has been identified by several studies. Depending on the type or origin of the tumor and components of the tumor microenvironment, CXCL14 plays a conflicting role in cancer. Although fibroblast-derived CXCL14 has a tumor-supportive role, epithelial-derived CXCL14 mainly inhibits tumor progression. Hence, this review will elucidate what is known on the mechanisms of CXCL14 and its therapeutic approaches in tumor treatment. CXCL14 is a promising approach for cancer immunotherapy.

Investigation of the structure of regulatory proteins interacting with glycosaminoglycans by combining NMR spectroscopy and molecular modeling - the beginning of a wonderful friendship

The interaction of regulatory proteins with extracellular matrix or cell surface-anchored glycosaminoglycans (GAGs) plays important roles in molecular recognition, wound healing, growth, inflammation and many other processes. In spite of their high biological relevance, protein-GAG complexes are significantly underrepresented in structural databases because standard tools for structure determination experience difficulties in studying these complexes. Co-crystallization with subsequent X-ray analysis is hampered by the high flexibility of GAGs. NMR spectroscopy experiences difficulties related to the periodic nature of the GAGs and the sparse proton network between protein and GAG with distances that typically exceed the detection limit of nuclear Overhauser enhancement spectroscopy. In contrast, computer modeling tools have advanced over the last years delivering specific protein-GAG docking approaches successfully complemented with molecular dynamics (MD)-based analysis. Especially the combination of NMR spectroscopy in solution providing sparse structural constraints with molecular docking and MD simulations represents a useful synergy of forces to describe the structure of protein-GAG complexes. Here we review recent methodological progress in this field and bring up examples where the combination of new NMR methods along with cutting-edge modeling has yielded detailed structural information on complexes of highly relevant cytokines with GAGs.

CDX2 enhances natural killer cell-mediated immunotherapy against head and neck squamous cell carcinoma through up-regulating CXCL14

(NK) cells are at the first line of defence against tumours, but their anti‐tumour mechanisms are not fully understood. We aimed to investigate the mechanism by which NK cells can mediate immunotherapy against head and neck squamous cell carcinoma (HNSCC). We collected fifty‐two pairs of HNSCC tissues and corresponding adjacent normal tissues; analysis by RT‐qPCR showed underexpression of CXCL14 in HNSCC tissues. Primary NK cells were then isolated from the peripheral blood of HNSCC patients and healthy donors. CXCL14 was found to be consistently under‐expressed in the primary NK cells from the HNSCC patients. However, CXCL14 expression was increased in IL2‐activated primary NK cells and NK‐92 cells. We next evaluated NK cell migration, IFN‐γ and TNF‐α expression, cytotoxicity and infiltration in response to CXCL14 overexpression or knockdown using gain‐ and loss‐of‐function approach. The results exhibited that CXCL14 overexpression promoted NK cell migration, cytotoxicity and infiltration. Subsequent in vivo experiments revealed that CXCL14 suppressed the growth of HNSCC cells via activation of NK cells. ChIP was applied to study the enrichment of H3K27ac, p300, H3K4me1 and CDX2 in the enhancer region of CXCL14, which showed that CDX2/p300 activated the enhancer of CXCL14 to up‐regulate its expression. Rescue experiments demonstrated that CDX2 stimulated NK cell migration, cytotoxicity and infiltration through up‐regulating CXCL14. In vivo data further revealed that CDX2 suppressed tumorigenicity of HNSCC cells through enhancement of CXCL14. To conclude, CDX2 promotes CXCL14 expression by activating its enhancer, which promotes NK cell–mediated immunotherapy against HNSCC.

MicroRNA-1278 ameliorates the inflammation of cardiomyocytes during myocardial ischemia by targeting both IL-22 and CXCL14

AIMS

This study aimed to elucidate the role of microRNAs (miRNAs) during myocardial infarction (MI) development in vivo and in vitro.

MAIN METHODS

Differentially expressed miRNAs between heart tissue from the MI mouse model and the control mouse were identified via microarray. Quantitative PCR (qPCR) and western blotting (WB) were performed to examine the expression levels of miRNAs and proteins, respectively. EdU-staining and colony formation assay were performed to assess cell viability and growth. Annexin V- and PI-staining-based flow cytometry was used to assess cell apoptosis. An MI mouse model was also established to study the function of miR-1278 in vivo.

KEY FINDINGS

The levels of miR-1278 were reduced in the infarct regions of heart tissues of the MI mouse model and in H2O2-treated newborn murine ventricular cardiomyocytes (NMVCs) compared to those in the heart tissues of healthy mice and non-treated NMVCs. H2O2 treatment suppressed the proliferation of NMVCs, while miR-1278 upregulation improved it. Moreover, we found that miR-1278 inhibited the upregulation of IL-22 and CXCL14 expression in H2O2-treated NMVCs by directly binding with the 3'-UTRs of both IL-22 and CXCL14. Furthermore, restoration of IL-22 and CXCL14 in H2O2-treated NMVCs promoted miR-1278-induced inflammation and apoptosis. Administration of agomiR-1278 to the MI mouse model significantly improved cardiac activity.

SIGNIFICANCE

Collectively, our findings illustrate that the expression of miR-1278 is low in H2O2-treated NMVCs and post-MI cardiac tissues, and the overexpression of miR-1278 in these protects against cell death by modulating IL-22 and CXCL14 expression.

The chemokine CXCL14 mediates platelet function and migration via direct interaction with CXCR4

AIMS

Beyond classical roles in thrombosis and haemostasis, it becomes increasingly clear that platelets contribute as key players to inflammatory processes. The involvement of platelets in these processes is often mediated through a variety of platelet-derived chemokines which are released upon activation and act as paracrine and autocrine factors. In this study, we investigate CXCL14, a newly described platelet chemokine and its role in thrombus formation as well as monocyte and platelet migration. In addition, we examine the chemokine receptor CXCR4 as a possible receptor for CXCL14 on platelets. Furthermore, with the use of artificially generated platelets derived from induced pluripotent stem cells (iPSC), we investigate the importance of CXCR4 for CXCL14-mediated platelet functions.

METHODS AND RESULTS

In this study, we showed that CXCL14 deficient platelets reveal reduced thrombus formation under flow compared with wild-type platelets using a standardized flow chamber. Addition of recombinant CXCL14 normalized platelet-dependent thrombus formation on collagen. Furthermore, we found that CXCL14 is a chemoattractant for platelets and mediates migration via CXCR4. CXCL14 promotes platelet migration of platelets through the receptor CXCR4 as evidenced by murine CXCR4-deficient platelets and human iPSC-derived cultured platelets deficient in CXCR4. We found that CXCL14 directly interacts with the CXCR4 as verified by immunoprecipitation and confocal microscopy.

CONCLUSIONS

Our results reveal CXCL14 as a novel platelet-derived chemokine that is involved in thrombus formation and platelet migration. Furthermore, we identified CXCR4 as principal receptor for CXCL14, an interaction promoting platelet migration.

Identification of genes associated with endometrial cell ageing

Ageing of the uterine endometrium is a critical factor that affects reproductive success, but the mechanisms associated with uterine ageing are unclear. In this study, we conducted a qualitative examination of age-related changes in endometrial tissues and identified candidate genes as markers for uterine ageing. Gene expression patterns were assessed by two RNA-sequencing experiments using uterine tissues from wild type (WT) C57BL/6 mice. Gene expression data obtained by RNA-sequencing were validated by real-time PCR. Genes expressing the pro-inflammatory cytokines Il17rb and chemokines Cxcl12 and Cxcl14 showed differential expression between aged WT mice and a group of mice composed of 5- and 8-week-old WT (young) animals. Protein expression levels of the above-mentioned genes and of IL8, which functions downstream of IL17RB, were analysed by quantitative immunohistochemistry of unaffected human endometrium tissue samples from patients in their 20s and 40s (10 cases each). In the secretory phase samples, 3,3'- diaminobenzidine staining intensities of IL17RB, CXCL12 and CXCL14 for patients in their 40s were significantly higher than that for patients in their 20s, as detected by a Mann-hitney U test. These results suggest that these genes are candidate markers for endometrial ageing and for prediction of age-related infertility, although confirmation of these findings is needed in larger studies involving fertile and infertile women.

A lncRNA Gpr137b-ps/miR-200a-3p/CXCL14 axis modulates hepatic stellate cell (HSC) activation

Hepatic fibrosis is the wound healing response upon the liver tissue damage caused by multiple stimuli. Targeting activated hepatic stellate cells (HSCs), the major extracellular matrix (ECM)-producing cells within the damaged liver, has been regarded as one of the main treatments for hepatic fibrosis. In the present study, we performed preliminary bioinformatics analysis attempting to identify possible factors related to hepatic fibrosis and found that lncRNA G protein-coupled receptor 137B (Gpr137b-ps) and C-X-C motif chemokine ligand 14 (CXCL14) showed to be markedly upregulated within carbon tetrachloride (CCl4)-caused hepatic fibrotic mice tissue samples and activated HSCs. CXCL14 The silencing of lncRNA Gpr137b-ps or CXCL14 alone could significantly improve CCl4-induced fibrotic changes in mice liver in vivo and collagen I and III release by HSCs and HSC proliferation in vitro. miR-200a-3p directly targeted lncRNA Gpr137b-ps and CXCL14, respectively. LncRNA Gpr137b-ps relieved miR-200a-3p-induced inhibition on CXCL14 expression via acting as a ceRNA. In HSCs, the effects of lncRNA Gpr137b-ps silencing on collagen I and III release by HSCs and HSC proliferation were significantly reversed by miR-200a-3p inhibition, and the effects of miR-200a-3p inhibition were reversed by CXCL14 silencing. In conclusion, we demonstrated a lncRNA Gpr137b-ps/miR-200a-3p/CXCL14 axis that modulates HSC activation and might exert an effect on the pathogenesis of liver fibrosis.

The Chemokine CXCL14-like Immunoreactivity Co-exists with Somatostatin, but not NPY in the Rat Dorsal Horn and Has Intimate Association with GABAergic Neurons in the Lateral Spinal Nucleus

Recent studies have proposed that the chemokine CXCL14 not only has a chemotactic activity, but also functions as a neuromodulator and/or neurotransmitter. In this study, we investigated the distribution of CXCL14 immunoreactive structures in the rat spinal cord and clarified the association of these structures with somatostatin, glutamic acid decarboxylase (GAD; a marker for GABAergic neurons), and neuropeptide Y (NPY). CXCL14 immunoreactive fibers and puncta were observed in lamina II, which modulates somatosensation including nociception, and the lateral spinal nucleus of the spinal dorsal horn at cervical, thoracic, and lumber spinal cord levels. These CXCL14 immunoreactive structures were also immuno-positive for somatostatin, but were immuno-negative for GAD and NPY. In the cervical lateral spinal nucleus, CXCL14 immunoreactive puncta, which were also immuno-positive for somatostatin, existed along the proximal dendrites of some of GABAergic neurons. Together, these results suggest that CXCL14 contributes to the modulation of somatosensation in concert with somatostatin. Neurons targeted by the CXCL14 fiber system include GABAergic neurons located in the lateral spinal nucleus suggesting that CXCL14 with somatostatin can influence the GABAergic neuron function.

circEYA1 Functions as a Sponge of miR-582-3p to Suppress Cervical Adenocarcinoma Tumorigenesis via Upregulating CXCL14

Circular RNAs (circRNAs) function as efficient microRNA (miRNA) sponges that regulate gene expression in the pathogenesis of many human malignancies. However, their roles in cervical adenocarcinoma remain largely unknown. In this study, we aimed to seek novel circRNAs that regulate cervical adenocarcinoma carcinogenesis and to explore their regulatory mechanisms as well as clinical significance. We identified that 24 circRNAs were differentially expressed in cervical adenocarcinoma tissues by RNA sequencing. Among them, circEYA1 was the most significantly downregulated circRNA in cervical adenocarcinoma. In cervical adenocarcinoma cells, circEYA1 overexpression led to suppression of cell viability and colony formation, promotion of apoptosis, and a decrease of the xenograft tumor growth. The mechanism underlying these observations is that circEYA1 functioned as a sponge of miR-582-3p and abrogated its suppression of CXCL14 expression. Consistently, miR-582-3p inhibition phenocopied the biological effects of circEYA1 overexpression in cervical adenocarcinoma cells. Moreover, miR-582-3p overexpression reversed the suppressive behaviors of circEYA1 in vitro and in vivo. In addition, the expression, correlation, and clinical diagnostic value of circEYA1/miR-582-3p/CXCL14 were confirmed in 198 clinical cervical tissue samples. In summary, our findings highlight a novel tumor suppressive role of circEYA1 in cervical adenocarcinoma tumorigenesis and may provide a potential diagnostic marker and therapeutic target for patients with cervical adenocarcinoma.

NFATc2-dependent epigenetic upregulation of CXCL14 is involved in the development of neuropathic pain induced by paclitaxel

Background

The major dose-limiting toxicity of paclitaxel, one of the most commonly used drugs to treat solid tumor, is painful neuropathy. However, the molecular mechanisms underlying paclitaxel-induced painful neuropathy are largely unclarified.

Methods

Paw withdrawal threshold was measured in the rats following intraperitoneal injection of paclitaxel. The qPCR, western blotting, protein or chromatin immunoprecipitation, ChIP-seq identification of NFATc2 binding sites, and microarray analysis were performed to explore the molecular mechanism.

Results

We found that paclitaxel treatment increased the nuclear expression of NFATc2 in the spinal dorsal horn, and knockdown of NFATc2 with NFATc2 siRNA significantly attenuated the mechanical allodynia induced by paclitaxel. Further binding site analysis utilizing ChIP-seq assay combining with gene expression profile revealed a shift of NFATc2 binding site closer to TTS of target genes in dorsal horn after paclitaxel treatment.

We further found that NFATc2 occupancy may directly upregulate the chemokine CXCL14 expression in dorsal horn, which was mediated by enhanced interaction between NFATc2 and p300 and consequently increased acetylation of histone H4 in CXCL14 promoter region. Also, knockdown of CXCL14 in dorsal horn significantly attenuated mechanical allodynia induced by paclitaxel.

Conclusion

These results suggested that enhanced interaction between p300 and NFATc2 mediated the epigenetic upregulation of CXCL14 in the spinal dorsal horn, which contributed to the chemotherapeutic paclitaxel-induced chronic pain.

Supplementary information

The online version contains supplementary material available at 10.1186/s12974-020-01992-1.

Chemokine CXCL14 acts as a potential genetic target for liver fibrosis

There are multiple causes of liver fibrosis, common ones include ethanol, toxins, and cholestasis. However, whether these different etiologies lead to the same pathological outcomes contain common genetic targets or signaling pathways, the current research has not attracted widespread attention. GSE40041 and GSE55747 were downloaded from the Gene Expression Omnibus (GEO) database. GSE40041 and GSE55747 represent the differential expression profiles in the liver of mice with bile duct ligation (BDL) and carbon tetrachloride (CCl4) induced liver fibrosis models, respectively. By using GEO2R, 701 differential expression genes (DEGs) in GSE40041 and 6540 DEGs in GSE55747 were identified. 260 co-DEGs were shared and extracted for gene ontology (GO) analysis. Through GO analysis, it was found that the regulation of cell migration in biological processes (BPs) was closely related to the pathogenesis of liver fibrosis, and the genes involved in this process include a key gene, chemokine (C-X-C motif) ligand 14 (CXCL14). Subsequently, further bioinformatic analysis showed that CXCL14 may be regulated by miR-122 to participate in the progression of liver fibrosis. Then real-time PCR and western blotting were performed to validate the expression of CXCL14 in liver tissue after liver fibrosis caused by different etiologies (ethanol, CCl4). The expression of CXCL4 in liver fibrosis induced by BDL was verified in another GEO dataset. Basically consistent with our bioinformatics results, our experimental results showed that the expression of CXCL14 was most significantly increased in alcoholic liver fibrosis model, followed by CCl4-induced liver fibrosis, which was also significantly increased in the BDL-induced model. Thus, CXCL14 can act as a common potential genetic target for different liver fibrosis diseases.

CXCL14 Maintains hESC Self-Renewal through Binding to IGF-1R and Activation of the IGF-1R Pathway

Human embryonic stem cells (hESCs) have important roles in regenerative medicine, but only a few studies have investigated the cytokines secreted by hESCs. We screened and identified chemokine (C-X-C motif) ligand 14 (CXCL14), which plays crucial roles in hESC renewal. CXCL14, a C-X-C motif chemokine, is also named as breast and kidney-expressed chemokine (BRAK), B cell and monocyte-activated chemokine (BMAC), and macrophage inflammatory protein-2γ (MIP-2γ). Knockdown of CXCL14 disrupted the hESC self-renewal, changed cell cycle distribution, and further increased the expression levels of mesoderm and endoderm differentiated markers. Interestingly, we demonstrated that CXCL14 is the ligand for the insulin-like growth factor 1 receptor (IGF-1R), and it can activate IGF-1R signal transduction to support hESC renewal. Currently published literature indicates that all receptors in the CXCL family are G protein-coupled receptors (GPCRs). This report is the first to demonstrate that a CXCL protein can bind to and activate a receptor tyrosine kinase (RTK), and also the first to show that IGF-1R has another ligand in addition to IGFs. These findings broaden our understanding of stem cell biology and signal transduction.

Two coupled mutations abolished the binding of CEBPB to the promoter of CXCL14 that displayed an antiviral effect on PRRSV by activating IFN signaling

Porcine reproductive and respiratory syndrome (PRRS) is the most economically important infectious disease of pigs worldwide. Our previous study revealed that Tongcheng (TC) pigs display higher resistance to PRRS than Largewhite (LW) pigs, but the genetic mechanism remains unknown. Here, we first confirmed that CXCL14 was downregulated in lungs and porcine alveolar macrophages (PAMs) responding to PRRS virus (PRRSV) infection, but the decline in LW pigs was more obvious than that in TC pigs. Then, we found that the overexpression of CXCL14 activated type-I interferon (IFN-I) signaling by upregulating interferon beta (IFNB), which plays a major role in the antiviral effect. To further decipher the mechanism underlying its differential expression, we characterized the core promoter of CXCL14 as being located from -145 to 276 bp of the transcription start site (TSS) and identified two main haplotypes that displayed significant differential transcriptional activities. We further identified two coupled point mutations that altered the binding status of CEBPB and were responsible for the differential expression in TC and LW pigs. The regulatory effect of CEBPB on CXCL14 was further confirmed by RNA interference (RNAi) and chromatin immunoprecipitation (ChIP), providing crucial clues for deciphering the mechanism of CXCL14 downregulation in unusual conditions. The present study revealed the potential antiviral effect of CXCL14, occurring via activation of interferon signaling, and suggested that CXCL14 contributes to the PRRS resistance of TC pigs.

Chemokine CXCL14-like immunoreactivity in the αMSH-producing cells and PRL-producing cells of the flat-tailed house gecko pituitary

The distribution pattern of chemokine CXCL14-immunoreactive cells was examined by immunohistochemistry in the pituitary of the gecko Hemidactylus platyurus. Immunoreactive cells were observed in the pars intermedia and pars distalis of the pituitary, but not in the pars nervosa. All α-melanocyte-stimulating hormone (αMSH)-producing cells were immunoreactive for CXCL14 in the pars intermedia. The CXCL14-immunoreactive cells corresponded to prolactin (PRL)-producing cells but not to other adenohypophyseal-hormone-producing cells in the pars distalis. CXCL14 secreted from αMSH-producing cells and PRL-producing cells may regulate insulin release from β cells in the pancreatic islets as well as glucose uptake in the muscle cells together with αMSH and/or PRL. In addition, secreted CXCL14 with αMSH and/or PRL may act as a bioactive factor regulating hormone release in the adenohypophyseal cells of the reptilian pars distalis.

The multifarious roles of the chemokine CXCL14 in cancer progression and immune responses

The chemokine CXCL14 is a highly conserved, homeostatic chemokine that is constitutively expressed in skin epithelia. Responsible for immune cell recruitment and maturation, as well as impacting epithelial cell motility, CXCL14 contributes to the establishment of immune surveillance within normal epithelial layers. Furthermore, CXCL14 is critical to upregulating major histocompatibility complex class I expression on tumor cells. Given these important roles, CXCL14 is often dysregulated in several types of carcinomas including cervical, colorectal, endometrial, and head and neck cancers. Its disruption has been shown to limit critical antitumor immune regulation and is correlated to poor patient prognosis. However, other studies have found that in certain cancers, namely pancreatic and some breast cancers, overexpression of stromal CXCL14 correlates with poor patient survival due to increased invasiveness. Contributing to the ambiguity CXCL14 plays in cancer is that the native CXCL14 receptor remains uncharacterized, although several candidate receptors have been proposed. Despite the complexity of CXCL14 functions, it remains clear that this chemokine is a key regulatory factor in cancer and represents a potential target for future cancer immunotherapies.

Downregulated microRNA-150 upregulates IRX1 to depress proliferation, migration, and invasion, but boost apoptosis of gastric cancer cells

OBJECTIVE

Many studies have reported the correlation of microRNAs (miRNAs) with cancers, yet few have proposed the function of miR-150 in gastric cancer. This study intends to discuss the role of miR-150 in gastric cancer development by regulating IRX1.

METHODS

Gastric cancer tissues and adjacent tissues were collected. MiR-150-3p, IRX1, CXCL14, and NF-κB (p65) expressions were detected. Gastric cancer cell lines SNU-1 and MKN-45 were used for subsequent cellular experiments. Cell proliferation, colony formation, migration and invasion, apoptosis, and cell cycle distribution in SNU-1 and MKN-45 cells were determined via gain-of and loss-of-function assays. The tumor growth in nude mice was also detected.

RESULTS

MiR-150, CXCL14, and NF-κB (p65) were upregulated and IRX1 was downregulated in gastric cancer tissues and cells. CXCL14 and NF-κB (p65) expression was positively related to miR-150 expression and negatively to IRX1 expression. MiR-150 inhibition and IRX1 overexpression in SNU-1 cells restricted viability, colony formation, migration, and invasion abilities, but boosted apoptosis of gastric cancer cells in vitro, and also repressed tumor growth in vivo. These results could be reversed by miR-150 elevation and IRX1 silencing, and the results from in vivo and in vitro experiments were consistent.

CONCLUSION

Our study reveals that miR-150 downregulation restrains proliferation, migration, and invasion, while facilitating apoptosis of gastric cancer cells by upregulating IRX1.

Suppressed Expression of CXCL14 in Hepatocellular Carcinoma Tissues and Its Reduction in the Advanced Stage of Chronic HBV Infection

Introduction

CXCL14 was a significantly under-expressed mRNA in hepatocellular carcinoma tissues according to our microarray analysis, as well as head and neck squamous cell carcinoma and cervical squamous cell carcinoma. CXCL14 was considered a tumor suppressor in some studies; however, its role in HBV infection has not been identified.

Methods

CXCL14 mRNA expression was quantified from 20 male HCC patients, and the fold change in cancer tissues was calculated by comparisons with normal adjacent tissues. Overall, 212 patients with chronic HBV infection and 180 HBV-free controls were recruited to investigate the association between CXCL14 polymorphisms and HBV progression as well as liver function parameters. Serum CXCL14 levels were determined by enzyme-linked immunosorbent assay (ELISA), and comparisons were made between different HBV status and different CXCL14 genotypes.

Results

The mRNA expression of CXCL14 was 0.33-fold in HCC tissues when compared with adjacent tissues. The frequencies of rs2237062 and rs2547, but not rs2237061, were significantly different between patients with mild hepatitis and moderate-to-severe hepatitis. Moreover, rs2237062 and rs2547 polymorphisms correlated with impaired liver function parameters. ELISA results suggested that HBV-free controls had the highest level of CXCL14, while mild hepatitis patients had low levels, and patients with moderate-to-severe hepatitis had the lowest level. GA+AA genotypes of rs2547 were associated with reduced levels of serum CXCL14 because it introduced a stop codon at residue 109.

Conclusion

CXCL14 was significantly suppressed in HBV-related HCC tissues, and its polymorphisms were linked with advanced stage chronic HBV infection and impaired liver function.

Foam Cell-Derived CXCL14 Muti-Functionally Promotes Atherogenesis and Is a Potent Therapeutic Target in Atherosclerosis

CXC chemokine family has been related to atherogenesis for long. However, the relationship between CXCL14 and atherogenesis is still unclear. This study preliminarily detected CXCL14 expression at foam cells in atherosclerosis specimens by immunohistochemistry. In vitro foam cells were derived from THP-1 after phorbol-12-myristate-13-acetate (PMA) and oxidized low-density lipoprotein (ox-LDL) stimulation. Immunoblotting and qPCR convinced CXCL14 expression variation during foam cell formation. We further demonstrated that ox-LDL regulated CXCL14 expression by AP-1. AP-1 could bind to CXCL14 promoter and up-regulate CXCL14 mRNA expression. Besides, CXCL14 promoted THP-1 migration, macrophage lipid phagocytosis, and smooth muscle cell migration as well as proliferation mainly via the ERK1/2 pathway. Additionally, a CXCL14 peptide-induced immune therapy showed efficacy in ApoE^-/- mouse model. In conclusion, our study demonstrated that CXCL14 is highly up-regulated during foam cell formation and promotes atherogenesis in various ways. CXCL14 may be a potent therapeutic target for atherosclerosis.