MiR-625-5p is a potential therapeutic target in sepsis by regulating CXCL16/CXCR6 axis and endothelial barrier.

BACKGROUND: MicroRNA plays an important role in the progression of sepsis. We found a significant increase of in miR-625-5p expression in the blood of patients with sepsis, and lipopolysaccharide (LPS)-stimulated EA.hy926 cells. To date, little is known about the specific biological function of miR-625-5p in sepsis. METHODS: Changes in miR-625-5p expression were verified through quantitative real-time polymerase chain reaction in 45 patients with sepsis or septic shock and 30 healthy subjects. In vitro, EA.hy926 cells were treated with LPS. Transendothelial electrical resistance assay and FITC-dextran were used in evaluating endothelial barrier function. RESULTS: Herein, patients with sepsis or septic shock had significantly higher miR-625-5p expression levels, chemokine (C-X-C motif) ligand 16 (CXCL16) levels, and glycocalyx components than the healthy controls, and miR-625-5p level was positively correlated with disease. Kaplan-Meier analysis demonstrated a strong association between miR-625-5p level and 28-day mortality. Furthermore, the miR-625-5p inhibitor significantly alleviated LPS-induced endothelial barrier injury in vitro. Then, miR-625-5p positively regulated CXCL16 and down-regulated miR-625-5p attenuated CXCL16 transcription and expression in EA.hy926 cells. CXCL16 knockout significantly alleviated vascular barrier dysfunction in the LPS-induced EA.hy926 cells. sCXCL16 treatment in EA.hy926 cells significantly increased endothelial hyperpermeability by disrupting endothelial glycocalyx, tight junction proteins, and adherens junction proteins through the modulation of C-X-C chemokine receptor type 6 (CXCR6). CONCLUSIONS: Increase in miR-625-5p level may be an effective biomarker for predicting 28-day mortality in patients with sepsis/septic shock. miR-625-5p is a critical pathogenic factor for endothelial barrier dysfunction in LPS-induced EA.hy926 cells because it activates the CXCL16/CXCR6 axis.

Identification of CXCL16 as a diagnostic biomarker for obesity and intervertebral disc degeneration based on machine learning.

Intervertebral disc degeneration (IDD) is the primary cause of neck and back pain. Obesity has been established as a significant risk factor for IDD. The objective of this study was to explore the molecular mechanisms affecting obesity and IDD by identifying the overlapping crosstalk genes associated with both conditions. The identification of specific diagnostic biomarkers for obesity and IDD would have crucial clinical implications. We obtained gene expression profiles of GSE70362 and GSE152991 from the Gene Expression Omnibus, followed by their analysis using two machine learning algorithms, least absolute shrinkage and selection operator and support vector machine-recursive feature elimination, which enabled the identification of C-X-C motif chemokine ligand 16 (CXCL16) as a shared diagnostic biomarker for obesity and IDD. Additionally, gene set variant analysis was used to explore the potential mechanism of CXCL16 in these diseases, and CXCL16 was found to affect IDD through its effect on fatty acid metabolism. Furthermore, correlation analysis between CXCL16 and immune cells demonstrated that CXCL16 negatively regulated T helper 17 cells to promote IDD. Finally, independent external datasets (GSE124272 and GSE59034) were used to verify the diagnostic efficacy of CXCL16. In conclusion, a common diagnostic biomarker for obesity and IDD, CXCL16, was identified using a machine learning algorithm. This study provides a new perspective for exploring the possible mechanisms by which obesity impacts the development of IDD.

TLR7-MyD88-DC-CXCL16 axis results neutrophil activation to elicit inflammatory response in pustular psoriasis.

Pustular psoriasis (PP) is a chronic inflammatory disease associated with multiple complications, often with hyperthermia and hypoproteinemia, and its continued progression can be life-threatening. Toll-like receptor 7 (TLR7) induces dendritic cell (DC) production of inflammatory factors that exacerbate the inflammatory response in PP. A membrane-bound chemokine expressed on DCs, CXC motif chemokine ligand 16 (CXCL16) is overexpressed in PP lesions, and neutrophils express its receptor CXC chemokine receptor 6 (CXCR6). There are few studies on the PP immune microenvironment and it is unclear whether TLR7 and CXCL16 can be used as targets in PP therapy. Skin tissue (n = 5) and blood (n = 20) samples were collected from PP and healthy normal controls. The skin tissue transcriptome was analyzed to obtain the differentially expressed genes, and the immune microenvironment was deciphered using pathway enrichment. Tissue sequencing analysis indicated that TLR7, CXCL16, DCs, and neutrophils were involved in the PP process. The enzyme-linked immunosorbent assay, reverse transcription-PCR, and scoring table results demonstrated that TLR7 induced DC secretion of CXCL16, which enabled neutrophil activation of the secretion of the inflammatory factors interleukin-8 (IL-8) and tumor necrosis factor alpha (TNF-α). The co-culture of neutrophils with DCs treated with TLR7 inhibitor or TLR7 agonist demonstrated that TLR7 regulated neutrophil activation, migration, and apoptosis. We constructed imiquimod-induced psoriasis-like skin lesions in wild-type, Cd11c-Cre Myd88f/f, and Mrp8-Cre Cxcr6f/f mice. The mouse models suggested that TLR7 might influence DC release of CXCL16 and neutrophil proinflammatory effects by interfering with the myeloid differentiation primary response gene 88 (MyD88) signaling pathway. In conclusion, the TLR7-MyD88-DC-CXCL16 axis is an important mechanism that promotes neutrophil migration to PP skin lesions and stimulates the inflammatory response.

ELK3-CXCL16 axis determines natural killer cell cytotoxicity via the chemotactic activity of CXCL16 in triple negative breast cancer.

Triple-negative breast cancer (TNBC) is the most challenging subtype of breast cancer because of its aggressive behavior and the limited therapeutic strategies available. In the last decade, immunotherapy has become a promising treatment to prolong survival in advanced solid cancers including TNBC. However, the efficacy of immunotherapy in solid cancers remains limited because solid tumors contain few tumor-infiltrating lymphocytes. Here, we show that targeting an ETS transcription factor ELK3 (ELK3) recruits immune cells including natural killer (NK) cells into tumors via the chemotactic activity of chemokine. ELK3 depletion increases CXCL16 expression level and promotes NK cell cytotoxicity through CXCL16-mediated NK cell recruitment in TNBC. In silico analysis showed that ELK3 is negatively correlated with CXCL16 expression in breast cancer patient samples. Low expression of ELK3 and high expression of CXCL16 were associated with a better prognosis. Low expression of ELK3 and high expression of CXCL16 were associated with increased expression of NK cell-related genes. Our findings demonstrate that the ELK3-CXCL16 axis modulates NK cell recruitment to increase NK cell cytotoxicity, suggesting that targeting the ELK3 gene could be an adjuvant strategy for increasing the efficacy of immunotherapy in TNBC.

Convergent transcriptomic and genomic evidence supporting a dysregulation of CXCL16 and CCL5 in Alzheimer's disease.

BACKGROUND: Neuroinflammatory factors, especially chemokines, have been widely reported to be involved in the pathogenesis of Alzheimer's disease (AD). It is unclear how chemokines are altered in AD, and whether dysregulation of chemokines is the cause, or the consequence, of the disease. METHODS: We initially screened the transcriptomic profiles of chemokines from publicly available datasets of brain tissues of AD patients and mouse models. Expression alteration of chemokines in the blood from AD patients was also measured to explore whether any chemokine might be used as a potential biomarker for AD. We further analyzed the association between the coding variants of chemokine genes and genetic susceptibility of AD by targeted sequencing of a Han Chinese case-control cohort. Mendelian randomization (MR) was performed to infer the causal association of chemokine dysregulation with AD development. RESULTS: Three chemokine genes (CCL5, CXCL1, and CXCL16) were consistently upregulated in brain tissues from AD patients and the mouse models and were positively correlated with Aß and tau pathology in AD mice. Peripheral blood mRNA expression of CXCL16 was upregulated in mild cognitive impairment (MCI) and AD patients, indicating the potential of CXCL16 as a biomarker for AD development. None of the coding variants within any chemokine gene conferred a genetic risk to AD. MR analysis confirmed a causal role of CCL5 dysregulation in AD mediated by trans-regulatory variants. CONCLUSIONS: In summary, we have provided transcriptomic and genomic evidence supporting an active role of dysregulated CXCL16 and CCL5 during AD development.

Reduced expression of CXCL16/CXCR6 is involved in the pathogenesis of hidradenitis suppurativa.

Mutations in the γ-secretase complex have been well-described in familial hidradenitis suppurativa (HS). No gene mutations have been identified in sporadic HS, which comprises 60%-70% of all HS cases. Obesity and smoking are risk factors for HS and are closely related to DNA methylation, an essential epigenetic phenomenon. Hence, we hypothesized that epigenetic modifications might be involved in sporadic HS. To investigate genes with aberrant methylation in sporadic HS cases and assess their expression in skin lesions and blood from patients with HS. Skin lesion samples and corresponding normal skin were obtained from three patients with HS and subjected to whole-genome DNA methylation sequencing. Blood samples were collected from 20 patients with HS and 20 healthy controls (HCs). The HS mouse model was established by applying tamoxifen to NcstnΔKC mice. Target gene expression was analysed by immunohistochemistry, immunofluorescence, western blotting, enzyme-linked immunosorbent assay (ELISA) and semiquantitative real-time polymerase chain reaction (RT-qPCR). Among 10 807 differentially methylated genes, we filtered 2101 genes with hypermethylated promoter regions, and following bioinformatics analyses, we focused on CXC chemokine ligand 16 (CXCL16). Subsequent functional experiments confirmed the downregulation of CXCL16 and its receptor, CXC chemokine receptor (CXCR) 6, in skin tissue from HS patients and NcstnΔKC mice. Serum CXCL16 concentrations were also significantly decreased in patients with HS. Our data revealed the downregulation of CXCL16 and CXCR6 in HS.

Single-cell RNA transcriptome analysis of CNS immune cells reveals CXCL16/CXCR6 as maintenance factors for tissue-resident T cells that drive synapse elimination.

BACKGROUND: Emerging RNA viruses that target the central nervous system (CNS) lead to cognitive sequelae in survivors. Studies in humans and mice infected with West Nile virus (WNV), a re-emerging RNA virus associated with learning and memory deficits, revealed microglial-mediated synapse elimination within the hippocampus. Moreover, CNS-resident memory T (TRM) cells activate microglia, limiting synapse recovery and inducing spatial learning defects in WNV-recovered mice. The signals involved in T cell-microglia interactions are unknown. METHODS: Here, we examined immune cells within the murine WNV-recovered forebrain using single-cell RNA sequencing to identify putative ligand-receptor pairs involved in intercellular communication between T cells and microglia. Clustering and differential gene analyses were followed by protein validation and genetic and antibody-based approaches utilizing an established murine model of WNV recovery in which microglia and complement promote ongoing hippocampal synaptic loss. RESULTS: Profiling of host transcriptome immune cells at 25 days post-infection in mice revealed a shift in forebrain homeostatic microglia to activated subpopulations with transcriptional signatures that have previously been observed in studies of neurodegenerative diseases. Importantly, CXCL16/CXCR6, a chemokine signaling pathway involved in TRM cell biology, was identified as critically regulating CXCR6 expressing CD8+ TRM cell numbers within the WNV-recovered forebrain. We demonstrate that CXCL16 is highly expressed by all myeloid cells, and its unique receptor, CXCR6, is highly expressed on all CD8+ T cells. Using genetic and pharmacological approaches, we demonstrate that CXCL16/CXCR6 not only is required for the maintenance of WNV-specific CD8 TRM cells in the post-infectious CNS, but also contributes to their expression of TRM cell markers. Moreover, CXCR6+CD8+ T cells are required for glial activation and ongoing synapse elimination. CONCLUSIONS: We provide a comprehensive assessment of the role of CXCL16/CXCR6 as an interaction link between microglia and CD8+ T cells that maintains forebrain TRM cells, microglial and astrocyte activation, and ongoing synapse elimination in virally recovered animals. We also show that therapeutic targeting of CXCL16 in mice during recovery may reduce CNS CD8+ TRM cells.

CXCL16/ERK1/2 pathway regulates human podocytes growth, migration, apoptosis and epithelial mesenchymal transition.

Primary nephrotic syndrome (PNS) is the commonest glomerular disease affecting children. Previous studies have confirmed that CXC motif chemokine ligand 16 (CXCL16) is involved in the pathogenesis of PNS. However, the exact mechanisms underlying the pathogenesis of PNS remain to be elucidated. Thus, the present study aimed to elucidate the role of CXCL16 in PNS. It was found that the expression of CXCL16 and extracellular signal­regulated kinases 1 and 2 (ERK1/2) were significantly increased in clinical PNS renal tissues using reverse transcription­quantitative PCR, western blot analysis and immunohistochemistry. Lentivirus overexpression or short hairpin RNA vector was used to induce the overexpression or knockdown of CXCL16 in podocytes, respectively. Overexpression of CXCL16 in podocytes could decrease the cell proliferation and increase the migration and apoptosis, whereas CXCL16 knockdown increased cell proliferation and decreased cell migration and apoptosis. Results of the present study further demonstrated that ERK2 protein expression was regulated by CXCL16. The knockdown of ERK2 expression reversed the effects of CXCL16 on the proliferation, apoptosis, migration and epithelial mesenchymal transition (EMT) of podocytes. Collectively, the findings of the present study highlighted that the CXCL16/ERK1/2 pathway regulates the growth, migration, apoptosis and EMT of human podocytes.

JNK and Jag1/Notch2 co-regulate CXCL16 to facilitate cypermethrin-induced kidney damage.

Cypermethrin (CYP), a widely-used composite pyrethroid pesticide, has underlying nephrotoxic effects. To elucidate potential roles of the MAPK pathway, the Jag/Notch pathway, and miRNAs in CYP-mediated kidney lesion, Sprague-Dawley rats and glomerular mesangial cells were used in this work. Results displayed that ß-CYP abnormally altered renal histomorphology and ultrastructures, induced renal DNA damage, and impaired renal functions, as evidenced by the increase in plasma levels of Cys-C and ß2-Mg. ß-CYP activated the JNK/c-Jun pathway by inducing ROS and oxidative stress. Meanwhile, ß-CYP changed the miRNA expression profile, miR-21-5p showing the most significant increase. Moreover, the Jag1/Notch2/Hes1 pathway was directly targeted by miR-21-5p, the mRNA and protein expression of Jag1, Notch2, and Hes1 being declined in vivo and in vitro. The chemokine CXCL16 was induced by ß-CYP, accompanied by the inflammatory factor production and inflammatory cell infiltration in kidneys. The specific JNK inhibitor, Jag1 overexpression, Hes1 overexpression, bidirectional Co-IP, ChIP, and CXCL16 silencing demonstrated that CXCL16 co-regulated by the JNK/c-Jun and Jag1/Notch2/Hes1 pathways elicited renal inflammation. Collectively, our findings indicate that ß-CYP is of nephrotoxicity and it not only directly changes renal histomorphology and ultrastructures, but induces CXCL16 to trigger renal inflammation via the JNK/c-Jun and Jag1/Notch2/Hes1 pathways, finally synergistically contributing to kidney damage.

Identification of a Novel Theranostic Signature of Metabolic and Immune-Inflammatory Dysregulation in Myocardial Infarction, and the Potential Therapeutic Properties of Ovatodiolide, a Diterpenoid Derivative.

Myocardial infarction (MI) is a multifactorial global disease, recognized as one of the leading causes of cardiovascular morbidity and mortality. Timely and correct diagnoses and effective treatments could significantly reduce incidence of complications and improve patient prognoses. In this study, seven unconventional differentially expressed genes (DEGs) (MAN2A2, TNFRSF12A, SPP1, CSNK1D, PLAUR, PFKFB3, and CXCL16, collectively termed the MTSCPPC signature) were identified through integrating DEGs from six MI microarray datasets. The pathological and theranostic roles of the MTSCPPC signature in MI were subsequently analyzed. We evaluated interactions of the MTSCPPC signature with ovatodiolide, a bioactive compound isolated from Anisomeles indica (L.) Kuntze, using in silico molecular docking tools and compared it to specific inhibitors of the members of the MTSCPPC signature. Single-cell transcriptomic analysis of the public databases revealed high expression levels of the MTSCPPC signature in immune cells of adult human hearts during an MI event. The MTSCPPC signature was significantly associated with the cytokine-cytokine receptor interactions, chemokine signaling, immune and inflammatory responses, and metabolic dysregulation in MI. Analysis of a micro (mi)RNA regulatory network of the MTSCPPC signature suggested post-transcriptional activation and the roles of miRNAs in the pathology of MI. Our molecular docking analysis suggested a higher potential for ovatodiolide to target MAN2A2, CSNK1D, and TNFRSF12A. Collectively, the results derived from the present study further advance our understanding of the complex regulatory mechanisms of MI and provide a potential MI theranostic signature with ovatodiolide as a therapeutic candidate.

Elevated plasma levels of CXCL16 in severe COVID-19 patients.

Genome-wide association studies have recently identified 3p21.31, with lead variant pointing to the CXCR6 gene, as the strongest thus far reported susceptibility risk locus for severe manifestation of COVID-19. In order the determine its role, we measured plasma levels of Chemokine (C-X-C motif) ligand 16 (CXCL16) in the plasma of COVID-19 hospitalized patients. CXCL16 interacts with CXCR6 promoting chemotaxis or cell adhesion. The CXCR6/CXCL16 axis mediates homing of T cells to the lungs in disease and hyper-expression is associated with localised cellular injury. To characterize the CXCR6/CXCL16 axis in the pathogenesis of severe COVID-19, plasma concentrations of CXCL16 collected at baseline from 115 hospitalized COVID-19 patients participating in ODYSSEY COVID-19 clinical trial were assessed together with a set of controls. We report elevated levels of CXCL16 in a cohort of COVID-19 hospitalized patients. Specifically, we report significant elevation of CXCL16 plasma levels in association with severity of COVID-19 (as defined by WHO scale) (P-value < 0.02). Our current study is the largest thus far study reporting CXCL16 levels in COVID-19 hospitalized patients (with whole-genome sequencing data available). The results further support the significant role of the CXCR6/CXCL16 axis in the immunopathogenesis of severe COVID-19 and warrants further studies to understand which patients would benefit most from targeted treatments.

CXCL16 Promotes Gastric Cancer Tumorigenesis via ADAM10-Dependent CXCL16/CXCR6 Axis and Activates Akt and MAPK Signaling Pathways.

Abnormal expression of CXC motif chemokine ligand 16 (CXCL16) has been demonstrated to be associated with tumor progression and metastasis, served as a prognostic factor in many cancers, with higher relative expression behaving as a marker of tumor progression. However, its role and mechanisms underlying progression and metastasis of gastric cancer (GC) are yet to be elucidated. In our investigation, public datasets and human GC tissue samples were used to determine the CXCL16 expression levels. Our results revealed that CXCL16 was upregulated in GC. The high expression CXCL16 in GC was significantly associated with histologic poor differentiation and pTNM staging. And high CXCL16 was positively correlated with the poor survival of GC patients. Gain-and loss-of-function experiments were employed to investigate the biological role of CXCL16 in proliferation and migration both in vitro and in vivo. Mechanically, Gene set enrichment analysis (GSEA) revealed that the epithelial­mesenchymal transition (EMT), Akt and MAPK signal pathway related genes were significantly enriched in the high CXCL16 group, which was confirmed by western blot. Moreover, overexpression CXCL16 promoted the disintegrin and metalloproteases (ADAM10) and the CXC motif chemokine receptor 6 (CXCR6) expression, which mediated the CXCL16/CXCR6 positive feedback loop in GC, with activating Akt and MAPK signaling pathways. Knocking down ADAM10 would interrupted the CXCL16/CXCR6 axis in the carcinogenesis and progression of GC. In conclusion, our findings offered insights into that CXCL16 promoted GC tumorigenesis by enhancing ADAM10-dependent CXCL16/CXCR6 axis activation.

CXCL16 may be a predisposing factor to atherosclerosis: An animal study.

Atherosclerosis (AS) is a chronic inflammatory process initiated when lipoprotein is retained in the arterial wall. Leukocyte recruitment accelerates this process. CXC chemokine ligand 16 (CXCL16) acts as a chemokine to attract immune cells and also facilitates the phagocytosis process of modified low­density lipoprotein. Whether CXCL16 promotes or inhibits the pathological process of AS remains to be elucidated. To clarify this, CXCL16 gene was introduced into C57BL/6J wild­type mice to establish a stable CXCL16 overexpression mouse model. The initial changes of AS in mice were induced by high­fat diet (HFD). To study how the interaction of HFD and CXCL16 affected fatty acid metabolism and deposition, body weight and plasma lipid profile were assessed. Soluble CXCL16, matrix metalloproteinase­9, monocyte chemoattractant protein­1 and intercellular adhesion molecule­1 were detected by immunohistochemistry and ELISA to identify how CXCL16 affects AS lesion formation. The present study suggested that overexpression of CXCL16 combined with HFD lead to atherogenesis by upregulating the aforementioned inflammatory related genes at a protein level. The present study was the first, to the best of the authors' knowledge, to build a CXCL16 homozygous transgenic mice model to study how overexpressed CXCL16 is associated with AS for intervening in the occurrence and development of AS.

Single-cell dissection of cellular components and interactions shaping the tumor immune phenotypes in ovarian cancer.

Distinct T cell infiltration patterns, i.e., immune infiltrated, excluded, and desert, result in different responses to cancer immunotherapies. However, the key determinants and biology underpinning these tumor immune phenotypes remain elusive. Here, we provide a high-resolution dissection of the entire tumor ecosystem through single-cell RNA-sequencing analysis of 15 ovarian tumors. Immune-desert tumors are characterized by unique tumor cell-intrinsic features, including metabolic pathways and low antigen presentation, and an enrichment of monocytes and immature macrophages. Immune-infiltrated and -excluded tumors differ markedly in their T cell composition and fibroblast subsets. Furthermore, our study reveals chemokine receptor-ligand interactions within and across compartments as potential mechanisms mediating immune cell infiltration, exemplified by the tumor cell-T cell cross talk via CXCL16-CXCR6 and stromal-immune cell cross talk via CXCL12/14-CXCR4. Our data highlight potential molecular mechanisms that shape the tumor immune phenotypes and may inform therapeutic strategies to improve clinical benefit from cancer immunotherapies.

The Role of CXCL16 in the Pathogenesis of Cancer and Other Diseases.

CXCL16 is a chemotactic cytokine belonging to the α-chemokine subfamily. It plays a significant role in the progression of cancer, as well as the course of atherosclerosis, renal fibrosis, and non-alcoholic fatty liver disease (NAFLD). Since there has been no review paper discussing the importance of this chemokine in various diseases, we have collected all available knowledge about CXCL16 in this review. In the first part of the paper, we discuss background information about CXCL16 and its receptor, CXCR6. Next, we focus on the importance of CXCL16 in a variety of diseases, with an emphasis on cancer. We discuss the role of CXCL16 in tumor cell proliferation, migration, invasion, and metastasis. Next, we describe the role of CXCL16 in the tumor microenvironment, including involvement in angiogenesis, and its significance in tumor-associated cells (cancer associated fibroblasts (CAF), microglia, tumor-associated macrophages (TAM), tumor-associated neutrophils (TAN), mesenchymal stem cells (MSC), myeloid suppressor cells (MDSC), and regulatory T cells (Treg)). Finally, we focus on the antitumor properties of CXCL16, which are mainly caused by natural killer T (NKT) cells. At the end of the article, we summarize the importance of CXCL16 in cancer therapy.

High miR-451 expression in peripheral blood mononuclear cells from subjects at risk of developing rheumatoid arthritis.

Individuals carrying anti-citrullinated protein antibodies (ACPA) are considered at high risk of developing rheumatoid arthritis (RA). The altered expression of miRNAs contributes to the pathogenesis of RA. We aimed to identify differentially expressed miRNAs in the peripheral blood of ACPA-positive individuals with arthralgia at risk of RA compared to healthy controls (HC) and to determine their implications in the preclinical phase of RA. A comprehensive analysis of miRNAs revealed the dysregulation of miR-451 in peripheral blood mononuclear cells (PBMC) and plasma from RA-risk individuals. Higher miR-451 expression in PBMC from RA-risk individuals was further validated. Notably, miR-451 was previously shown to regulate CXCL16, a protein involved in RA pathogenesis. The expression of miR-451 in PBMC positively correlated with the CXCL16 mRNA, which could be secondary to the inflammation-induced expression of miR-451. Transfection of monocytes with pre-miR-451 in vitro resulted in the downregulation of CXCL16. Moreover, flow cytometry revealed a lower count of CXCL16-positive monocytes in RA-risk individuals. We propose that the constitutive or inflammation-induced upregulation of miR-451 in PBMC downregulates the expression of CXCL16, reduces the inflammatory milieu and thereby strives to delay the shift from the preclinical phase to the clinical manifestation of RA. This hypothesis warrants further investigation.

C-X-C motif chemokine 16, modulated by microRNA-545, aggravates myocardial damage and affects the inflammatory responses in myocardial infarction.

BACKGROUND: Myocardial infarction (MI), a common type of coronary heart disease, is the major cause of morbidity and mortality around the world. Chemokine-mediated inflammatory cell infiltration and local inflammatory damage response are recent research hotspots. Hence, we attempted to examine the role of C-X-C motif chemokine 16 (CXCL16) as a potential candidate in MI. METHODS: Human cardiomyocytes were treated with hypoxia/reoxygenation (H/R) to establish an in vitro cell model. GEO database provided the clinical data of MI patients and GSEA verified the relationship of chemokine and MI. CCK-8 and flow cytometry analyses were used to measure cell viability and apoptosis. Bioinformatics analysis and luciferase reporter assay were conducted to determine the correlation between CXCL16 and miR-545. qRT-PCR and western blot assays were performed to investigate the expression level of the indicated genes. The activity of lactate dehydrogenase (LDH) and the levels of TNF-α, IL-6, IL-1ß, and IL-10 were explored using ELISA assay. RESULTS: CXCL16 was increased in MI. CXCL16 knockdown can reverse the inhibitory effect of H/R treatment on cell viability, while overexpression of CXCL16 showed the opposite trend. MiR-545 directly targeted CXCL16 and negatively regulated CXCL16 levels. MiR-545 promoted cell proliferation and inhibited apoptosis in the MI cell model, which attenuated the CXCL16-induced injury on cardiomyocytes. CONCLUSION: These findings demonstrated that CXCL16 aggravated MI damage through being directly targeted by miR-545 and mediating inflammatory responses, thereby providing potential therapeutic targets for MI therapy.

Circ_0000524/miR-500a-5p/CXCL16 axis promotes podocyte apoptosis in membranous nephropathy.

BACKGROUND: Podocytes apoptosis is a hallmark of membranous nephropathy (MN). Circ_0000524 has been reported to be associated with patients with MN, whereas the effect of circ_0000524 on podocytes apoptosis and the underlying mechanisms in MN have not been elaborated. METHODS: Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot were performed to detect the expressions of circ_0000524, microRNA-500a-5p (miR-500a-5p), and C-X-C chemokine ligand 16 (CXCL16) in MN tissues and podocytes. Podocyte injury was induced by angiotensin II (AngII). Cell apoptosis was detected by flow cytometry. Caspase-3 or caspase-9 activity was evaluated using a caspase-3 or caspase-9 activity assay kit, respectively. Dual-luciferase reporter assay, RNA immunoprecipitation (RIP) and pull-down assay were used to address the relationship among circ_0000524,miR-500a-5p and CXCL16. RESULTS: Upregulation of circ_0000524 and CXCL16 and low expression of miR-500a-5p were observed in MN tissues. AngII treatment induced the overexpression of circ_0000524 and CXCL16, a decrease of miR-500a-5p, and induced cell apoptosis in podocytes. Circ_0000524 negatively modulated the expression of miR-500a-5p. Circ_0000524 depletion inhibited podocyte apoptosis, which was rescued by loss of miR-500a-5p. miR-500a-5p contained the binding sites with CXCL16. Circ_0000524 knockdown hampered CXCL16 expression by upregulating miR-500a-5p expression. Additionally, miR-500a-5p upregulation suppressed AngII-induced podocyte apoptosis, which was rescued by enhanced expression of CXCL16. CONCLUSION: Circ_0000524/miR-500a-5p/CXCL16 pathway regulated podocyte apoptosis in MN.

Time-dependent cytokine and chemokine changes in mouse cerebral cortex following a mild traumatic brain injury.

Traumatic brain injury (TBI) is a serious global health problem, many individuals live with TBI-related neurological dysfunction. A lack of biomarkers of TBI has impeded medication development. To identify new potential biomarkers, we time-dependently evaluated mouse brain tissue and neuronally derived plasma extracellular vesicle proteins in a mild model of TBI with parallels to concussive head injury. Mice (CD-1, 30-40 g) received a sham procedure or 30 g weight-drop and were euthanized 8, 24, 48, 72, 96 hr, 7, 14 and 30 days later. We quantified ipsilateral cortical proteins, many of which differed from sham by 8 hours post-mTBI, particularly GAS-1 and VEGF-B were increased while CXCL16 reduced, 23 proteins changed in 4 or more of the time points. Gene ontology pathways mapped from altered proteins over time related to pathological and physiological processes. Validation of proteins identified in this study may provide utility as treatment response biomarkers.

oxLDL promotes podocyte migration by regulating CXCL16, ADAM10 and ACTN4.

Nephrotic syndrome (NS) is one of the most common causes of chronic kidney disease in the pediatric population. Hyperlipidemia is one of the main features of NS. The present study investigated the role of CXC motif chemokine ligand 16 (CXCL16) and ADAM metallopeptidase domain 10 (ADAM10) in oxidized low­density lipoprotein (oxLDL)­stimualted podocytes and the underlying mechanisms. CXCL16 and ADAM10 expression levels in oxLDL­treated podocytes were measured via reverse transcription­quantitative PCR and western blotting. Cell migration assays were conducted to assess the migration of oxLDL­treated podocytes. CXCL16 or ADAM10 overexpression and knockdown assays were conducted. The results indicated that oxLDL stimulation increased ADAM10 and CXCL16 expression levels, and enhanced podocyte migration compared with the control group. Moreover, CXCL16 and ADAM10 overexpression significantly increased podocyte migration and the expression of actinin­α4 (ACTN4) compared with the control groups. By contrast, CXCL16 and ADAM10 knockdown significantly reduced podocyte migration and the expression of ACTN4 compared with the control groups. The results suggested that oxLDL promoted podocyte migration by regulating CXCL16 and ADAM10 expression, as well as by modulating the actin cytoskeleton. Therefore, CXCL16 and ADAM10 may serve as novel therapeutic targets for primary nephrotic syndrome in children.