Identification of hub genes and potential biomarkers of neutrophilic asthma: evidence from a bioinformatics analysis.

OBJECTIVE: Asthma is a chronic airway inflammatory disease caused by multiple genetic and environmental factors. This study mainly sought to provide potential therapeutic targets and biomarkers for neutrophilic asthma (NA). METHODS: Three gene expression profiling datasets were obtained from the Genome Expression Omnibus (GEO) database. GSE45111 and GSE41863 were used to identify hub genes and potential biomarkers, and GSE137268 was used for data verification. We verified the repeatability of intragroup data and identified differentially expressed genes (DEGs). Then, we conducted Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of the DEGs, and a protein-protein interaction (PPI) network was constructed to identify the hub genes. Finally, receiver operating characteristic (ROC) analysis was used to verify the ability of the hub genes to differentiate between NA and eosinophilic asthma (EA). RESULTS: In this study, we identified 411 DEGs by comprehensive analysis of NA/EA patients and NA/healthy controls (HCs). Ten hub genes (CXCR1, FCGR3B, CXCR2, SELL, S100A12, CSF3R, IL6R, JAK3, CD48, and GNG2) were identified from the PPI network. Finally, based on the ROC analysis, 7 genes showed good diagnostic value for discriminating NA from EA-CXCR1, FCGR3B, CXCR2, SELL, S100A12, CSF3R, and IL6R (AUC > 0.7). CONCLUSION: We identified 7 hub genes that can distinguish NA from EA. The IL-8-mediated signaling may be the primary pathway to determine the NA phenotype in asthma. CXCR1/2 and S100A12 may be the primary genes determining the NA phenotype. CXCR1/2 and S100A12 might be biomarkers and new therapeutic targets for NA.Supplemental data for this article is available online at at.

Genetic landscape and autoimmunity of monocytes in developing Vogt-Koyanagi-Harada disease.

Vogt-Koyanagi-Harada (VKH) disease is a systemic autoimmune disorder affecting multiple organs, including eyes, skin, and central nervous system. It is known that monocytes significantly contribute to the development of autoimmune disease. However, the subset heterogeneity with unique functions and signatures in human circulating monocytes and the identity of disease-specific monocytic populations remain largely unknown. Here, we employed an advanced single-cell RNA sequencing technology to systematically analyze 11,259 human circulating monocytes and genetically defined their subpopulations. We constructed a precise atlas of human blood monocytes, identified six subpopulations-including S100A12, HLA, CD16, proinflammatory, megakaryocyte-like, and NK-like monocyte subsets-and uncovered two previously unidentified subsets: HLA and megakaryocyte-like monocyte subsets. Relative to healthy individuals, cellular composition, gene expression signatures, and activation states were markedly alternated in VKH patients utilizing cell type-specific programs, especially the CD16 and proinflammatory monocyte subpopulations. Notably, we discovered a disease-relevant subgroup, proinflammatory monocytes, which showed a discriminative gene expression signature indicative of inflammation, antiviral activity, and pathologic activation, and converted into a pathologic activation state implicating the active inflammation during VKH disease. Additionally, we found the cell type-specific transcriptional signature of proinflammatory monocytes, ISG15, whose production might reflect the treatment response. Taken together, in this study, we present discoveries on accurate classification, molecular markers, and signaling pathways for VKH disease-associated monocytes. Therapeutically targeting this proinflammatory monocyte subpopulation would provide an attractive approach for treating VKH, as well as other autoimmune diseases.

LPS and oxLDL-induced S100A12 and RAGE expression in carotid arteries of atherosclerotic Yucatan microswine.

BACKGROUND: S100A12, also known as Calgranulin C, is a ligand for the receptor for advanced glycation end products (RAGE) and plays key roles in cardiovascular and other inflammatory diseases. Interactions between S100A12 and RAGE initiate downstream signaling activating extracellular signal-regulated kinases (ERK1/2), mitogen activated protein kinases (MAPK), and transcription factor NF-κB. This increases the expression of pro-inflammatory cytokines to induce the inflammatory response. S100A12, and RAGE play a critical role in the development and progression of atherosclerosis. There is a well-known relationship between the bacterial endotoxin lipopolysaccharide (LPS) and the lipid antigens oxidized low-density lipoprotein (oxLDL) in driving the immune response in atherosclerosis. METHODS AND RESULTS: Our study aimed to compare the potential of LPS and oxLDL in regulating the expression of S100A12 and RAGE in atherosclerosis. The expression of these proteins was assessed in the harvested carotid arteries from LPS- and oxLDL-treated atherosclerotic Yucatan microswine. Tissues were collected from five different treatment groups: (i) angioplasty alone, (ii) LPS alone, (iii) oxLDL alone, (iv) angioplasty with LPS, and (v) angioplasty with oxLDL. Immunohistochemical findings revealed that angioplasty with LPS induced higher expression of S100A12 and RAGE compared to other treatment groups. The results were further corroborated by testing their gene expression through qPCR in cultured vascular smooth muscle cells (VSMCs) isolated from control carotid arteries and LPS- and oxLDL-treated arteries. CONCLUSIONS: The results of this study suggest that LPS induces the expression of S100A12 and RAGE more than oxLDL in atherosclerotic artery and both S100A12 and RAGE could be therapeutic targets.

Associations between COVID-19 and skin conditions identified through epidemiology and genomic studies.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is commonly associated with skin manifestations, and may also exacerbate existing skin diseases, yet the relationship between COVID-19 and skin diseases remains unclear. OBJECTIVE: By investigating this relationship through a multiomics approach, we sought to ascertain whether patients with skin conditions are more susceptible to COVID-19. METHODS: We conducted an epidemiological study and then compared gene expression across 9 different inflammatory skin conditions and severe acute respiratory syndrome coronavirus 2-infected bronchial epithelial cell lines, and then performed a genome-wide association study transdisease meta-analysis between COVID-19 susceptibility and 2 skin diseases (psoriasis and atopic dermatitis). RESULTS: Skin conditions, including psoriasis and atopic dermatitis, increase the risk of COVID-19 (odds ratio, 1.55; P = 1.4 × 10-9) but decrease the risk of mechanical ventilation (odds ratio, 0.22; P = 8.5 × 10-5). We observed significant overlap in gene expression between the infected normal bronchial epithelial cells and inflammatory skin diseases, such as psoriasis and atopic dermatitis. For genes that are commonly induced in both the severe acute respiratory syndrome coronavirus 2 infection and skin diseases, there are 4 S100 family members located in the epidermal differentiation complex, and we also identified the "IL-17 signaling pathway" (P = 4.9 × 10-77) as one of the most significantly enriched pathways. Furthermore, a shared genome-wide significant locus in the epidermal differentiation complex was identified between psoriasis and severe acute respiratory syndrome coronavirus 2 infection, with the lead marker being a significant expression quantitative trait locus for S100A12 (P = 3.3 × 10-7). CONCLUSIONS: Together our findings suggest association between inflammatory skin conditions and higher risk of COVID-19, but with less severe course, and highlight shared components involved in anti-COVID-19 immune response.

The alarmin S100A12 causes sterile inflammation of the human chorioamniotic membranes as well as preterm birth and neonatal mortality in mice†.

Sterile inflammation is triggered by danger signals, or alarmins, released upon cellular stress or necrosis. Sterile inflammation occurring in the amniotic cavity (i.e. sterile intra-amniotic inflammation) is frequently observed in women with spontaneous preterm labor resulting in preterm birth, the leading cause of neonatal morbidity and mortality worldwide; this condition is associated with increased amniotic fluid concentrations of alarmins. However, the mechanisms whereby alarmins induce sterile intra-amniotic inflammation are still under investigation. Herein, we investigated the mechanisms whereby the alarmin S100A12 induces inflammation of the human chorioamniotic membranes in vitro and used a mouse model to establish a causal link between this alarmin and adverse perinatal outcomes. We report that S100A12 initiates sterile inflammation in the chorioamniotic membranes by upregulating the expression of inflammatory mediators such as pro-inflammatory cytokines and pattern recognition receptors. Importantly, S100A12 induced the priming and activation of inflammasomes, resulting in caspase-1 cleavage and the subsequent release of mature IL-1ß by the chorioamniotic membranes. This alarmin also caused the activation of the chorioamniotic membranes by promoting MMP-2 activity and collagen degradation. Lastly, the ultrasound-guided intra-amniotic injection of S100A12 at specific concentrations observed in the majority of women with sterile intra-amniotic inflammation induced preterm birth (rates: 17% at 200 ng/sac; 25% at 300 ng/sac; 25% at 400 ng/sac) and neonatal mortality (rates: 22% at 200 ng/sac; 44% at 300 ng/sac; 31% at 400 ng/sac), thus demonstrating a causal link between this alarmin and adverse perinatal outcomes. Collectively, our findings shed light on the inflammatory responses driven by alarmins in the chorioamniotic membranes, providing insight into the immune mechanisms leading to preterm birth in women with sterile intra-amniotic inflammation.

Serum S100A12 levels: Possible association with skin sclerosis and interstitial lung disease in systemic sclerosis.

Damage-associated molecular patterns (DAMPs) have drawn much attention as a member of disease-associated molecules in systemic sclerosis (SSc). In this study, we investigated the potential contribution of S100A12, a member of DAMPs, to the development of SSc by evaluating S100A12 expression in the lesional skin and the clinical correlation of serum S100A12 levels. S100A12 expression was markedly elevated in the epidermis of SSc-involved skin at protein levels and in the bulk skin at mRNA levels. The deficiency of transcription factor Fli1, a predisposing factor of SSc, enhanced S100A12 expression and Fli1 occupied the S100A12 promoter in normal human keratinocytes. Serum S100A12 levels were higher in SSc patients, especially in those with diffuse cutaneous involvement, than in healthy controls and positively correlated with skin score. Furthermore, the presence of interstitial lung disease significantly augmented serum levels of S100A12. Importantly, serum S100A12 levels correlated inversely with both per cent forced vital capacity and per cent diffusing capacity for carbon monoxide and positively with serum levels of KL-6 and surfactant protein-D. Collectively, these results indicate a possible contribution of S100A12 to skin sclerosis and interstitial lung disease associated with SSc, further supporting the critical roles of DAMPs in the pathogenesis of this disease.

Characterization and engineering of S100A12-heparan sulfate interactions.

S100A12, an EF-hand calcium-binding protein, can be secreted by a variety of cell types and plays proinflammatory roles in a number of pathological conditions. Although S100A12 has been shown to interact with heparan sulfate (HS), the molecular detail of the interaction remains unclear. Here we investigate the structural basis of S100A12-HS interaction and how the interaction is regulated by the availability of divalent cations and the oligomeric states of S100A12. We discovered that S100A12-HS interaction requires calcium, while zinc can further enhance binding by inducing S100A12 hexamerization. In contrast, the apo form and zinc-induced tetramer form were unable to bind HS. Guided by the crystal structures of S100A12, we have identified the HS-binding site of S100A12 by site-directed mutagenesis. Characterization of the HS-binding site of S100A12 allowed us to convert the non-HS-binding apo and tetramer forms of S100A12 into a high affinity HS-binding variant by engineering a single-point mutation. Using a HS oligosaccharide microarray, we demonstrated that the N43K mutant displayed markedly enhanced selectivity toward longer HS oligosaccharides compared to the WT S100A12, likely due to the expanded dimension of the reengineered HS-binding site in the mutant. This unexpected finding strongly suggests that HS-binding sites of proteins might be amenable for engineering.

Downregulation of S100 calcium binding protein A12 inhibits the growth of glioma cells.

BACKGROUND: S100 calcium binding protein A12 (S100A12) is a member of the S100 protein family and is widely expressed in neutrophil and low expressed in lymphocytes and monocyte. However, the role of S100A12 in glioma has not yet been identified. METHODS: In the present study, we carried out immunohistochemical investigation of S100A12 in 81 glioma tissues to determine the expression of S100A12 in glioma cells, and evaluate the clinical significance of S100A12 in glioma patients. Futher we knockdown the S100A12 by shRNA, and evaluated cell proliferation, cell migration and cell apoptosis by MTT, colony formation assay, transwell assay,flow cytometry assa and western blot. RESULTS: We found that S100A12 was upregulated in tissues of glioma patients and the expression was correlated to WHO stage and tumor size. Further, we found that knockdown S100A12 inhibits the proliferation, migration and invasion of glioma cells through regulating cell apoptosis and EMT. CONCLUSION: S100A12 plays a vital role in glioma progression, and may be an important regulatory molecule for biological behaviors of glioma cell lines.

Ca(II) and Zn(II) Cooperate To Modulate the Structure and Self-Assembly of S100A12.

S100A12 is a member of the Ca2+ binding S100 family of proteins that functions within the human innate immune system. Zinc sequestration by S100A12 confers antimicrobial activity when the protein is secreted by neutrophils. Here, we demonstrate that Ca2+ binding to S100A12's EF-hand motifs and Zn2+ binding to its dimeric interface cooperate to induce reversible self-assembly of the protein. Solution and magic angle spinning nuclear magnetic resonance spectroscopy on apo-, Ca2+-, Zn2+-, and Ca2+,Zn2+-S100A12 shows that significant metal binding-induced chemical shift perturbations, indicative of conformational changes, occur throughout the polypeptide chain. These perturbations do not originate from changes in the secondary structure of the protein, which remains largely preserved. While the overall structure of S100A12 is dominated by Ca2+ binding, Zn2+ binding to Ca2+-S100A12 introduces additional structural changes to helix II and the hinge domain (residues 38-53). The hinge domain of S100A12 is involved in the molecular interactions that promote chemotaxis for human monocyte, acute inflammatory responses and generates edema. In Ca2+-S100A12, helix II and the hinge domain participate in binding with the C-type immunoglobulin domain of the receptor for advanced glycation products (RAGE). We discuss how the additional conformational changes introduced to these domains upon Zn2+ binding may also impact the interaction of S100A12 and target proteins such as RAGE.

High expression of S100 calgranulin genes in peripheral blood mononuclear cells from patients with Takayasu arteritis.

BACKGROUND: Toll-like receptors (TLR) 1 to 4 are highly expressed in aorta. Activation of TLR4 causes transmural arteritis in Human temporal artery-SCID chimera model. Neither TLR-4 nor its ligands have been studied in TA patients as yet. Aim of this study was to examine the expression of TLR4 and its endogenous ligands in peripheral blood mononuclear cells (PBMCs) of patients with Takayasu arteritis (TA). METHODS: mRNA expression of TLR4, RAGE and various endogenous TLR4 ligands were quantified in PBMCs of 24 TA patients and 19 sex and age matched healthy controls by real time PCR using specific primers and SYBR Green qPCR master mix. S100A8/A9 and S100A12 were measured in cell culture supernatant of PBMCs from TA patients and healthy controls, both in un-stimulated state as well as, after lipopolysaccharides (LPS) stimulated cultures for 4 h. Expression of S100A8/A9 in aortic tissues was assessed by immunohistochemistry. RESULTS: The mRNA expression of S100A8, S100A9, S100A12 and TLR4 were higher, while expression of RAGE and HSP70 were lower in TA as compared to healthy controls. Induction with LPS led to increase in secretion of both S100A8/A9 and S100A12 levels in TA as well as healthy controls. The fold of induction, measured by LPS stimulated/unstimulated control was higher in healthy controls [2.88 (1.7-3.53) fold] as compared to TA [1.345 (1-1.82) fold]; p < 0.05. Numerically, S100A8/A9 was also higher in healthy controls [2.04 (1.7-5.6) fold] as compared to TA [1.38 (1.09-3.6) fold], but it didn't reach statistical significance; p = 0.129. Mild to moderate intensity expression of S100A8/A9 protein was noted in aortic tissues from patients with TA. CONCLUSION: mRNA expression of TLR4 and its ligand S100A8, S100A9, and S100A12 in PBMCs of TA patients was higher as compared to healthy controls. LPS stimulation led to higher induction of S100A12 secretion in healthy controls as compared to TA. Expression of S100A8/A9 was detected in inflamed aortic tissues from patients with TA.

Apremilast for moderate hidradenitis suppurativa: no significant change in lesional skin inflammatory biomarkers.

BACKGROUND: Treatment with apremilast has recently demonstrated clinically meaningful improvement in moderate hidradenitis suppurativa (HS). OBJECTIVE: To evaluate the change in expression of inflammatory markers in lesional skin of HS patients receiving apremilast 30 mg twice daily (n = 15) for 16 weeks compared with placebo (n = 5). METHODS: At baseline, 5-mm punch biopsies were obtained from an index lesion (HSL) and non-lesional (HSN) skin in the same anatomical area. Subsequent HSL samples were taken as close as possible to the previously biopsied site at week 4 and week 16. After sampling, biopsies were split; one half was processed for in vivo mRNA analysis using real-time quantitative PCR; the other half was cultured for ex vivo protein analysis using a proximity extension assay (Olink). Linear mixed effects models were calculated to compare the levels of inflammatory markers in HSL skin between apremilast and placebo over time. RESULTS: At baseline, 17 proteins with a fold change >2 in HSL vs. HSN skin were identified in 20 patients. The top five were IL-17A (5), S100A12, CST5, IL-12/23p40, CD6 (1) with fold changes ranging from 6.6 to 1638, respectively (FDR <0.044). Linear mixed effects models for 75 assays were calculated. Protein levels of S100A12 decreased during treatment in the apremilast group compared with the placebo group (p = 0.014, FDR = 0.186). None of the 14 genes exhibited significant changes in expression over time. However, an evident downward trend in relative mRNA expression of IL-17A and IL-17F was demonstrated in patients receiving apremilast. CONCLUSION: We did not detect statistically significant changes in inflammatory markers in HSL skin of HS patients receiving apremilast compared with placebo, despite clinical improvement in the apremilast group. Nonetheless, S100A12 and IL-17A were significantly elevated in HSL skin and showed a decrease in response to apremilast. The translational model in clinical trials involving HS clearly needs further improvement.

DNA Methylation Regulates RGS2-induced S100A12 Expression in Airway Epithelial Cells.

RGS2 is a key modulator of stress in human airway epithelial cells, especially of hyperresponsiveness and mucin hypersecretion, both of which are features of cystic fibrosis (CF). Because its expression can be modulated through the DNA methylation pathway, we hypothesize that RGS2 is downregulated by DNA hypermethylation in CF airway epithelial cells. This downregulation would then lead to an enhanced inflammatory response. We demonstrated RGS2 transcript and protein downregulation in cultured airway epithelial cells from patients with CF and validated our findings in two CF epithelial cell lines. A methylated DNA immunoprecipitation array showed the presence of methylated cytosine on 13 gene promoters in CF. Among these genes, we confirmed that the RGS2 promoter was hypermethylated by using bisulfite conversion coupled with a methylation-specific PCR assay. Finally, we showed that downregulation of RGS2 in non-CF cells increased the expression of S100A12, a proinflammatory marker. These results highlight the importance of epigenetic regulation in gene expression in CF and show that RGS2 might modulate the inflammatory response in CF through DNA methylation control.

The Host Antimicrobial Protein Calgranulin C Participates in the Control of Campylobacter jejuni Growth via Zinc Sequestration.

Campylobacter jejuni is a leading cause of bacterially derived gastroenteritis worldwide. Campylobacter is most commonly acquired through the consumption of undercooked poultry meat or through drinking contaminated water. Following ingestion, Campylobacter adheres to the intestinal epithelium and mucus layer, causing toxin-mediated inflammation and inhibition of fluid reabsorption. Currently, the human response to infection is relatively unknown, and animal hosts that model these responses are rare. As such, we examined patient fecal samples for the accumulation of the neutrophil protein calgranulin C during infection with Campylobacter jejuni In response to infection, calgranulin C was significantly increased in the feces of humans. To determine whether calgranulin C accumulation occurs in an animal model, we examined disease in ferrets. Ferrets were effectively infected by C. jejuni, with peak fecal loads observed at day 3 postinfection and full resolution by day 12. Serum levels of interleukin-10 (IL-10) and tumor necrosis factor alpha (TNF-α) significantly increased in response to infection, which resulted in leukocyte trafficking to the colon. As a result, calgranulin C increased in the feces of ferrets at the time when C. jejuni loads decreased. Further, the addition of purified calgranulin C to C. jejuni cultures was found to inhibit growth in a zinc-dependent manner. These results suggest that upon infection with C. jejuni, leukocytes trafficked to the intestine release calgranulin C as a mechanism for inhibiting C. jejuni growth.

Effects of S100A12 gene silencing on serum levels of anti-inflammatory/pro-inflammatory cytokines in septic rats through the ERK signaling pathway.

We explored the effect of S100A12 gene on serum levels of anti-inflammatory/pro-inflammatory cytokines in septic rats by activating the extracellular signal-regulated kinase (ERK) signaling pathway. A total of 180 specific pathogen-free (SPF) rats were purchased to establish cecal ligation and puncture (CLP) model. Rats were assigned into the sham, model, empty vector, S100A12 siRNA, epidermal growth factor (EGF), and S100A12 siRNA + EGF groups. The expressions of S100A12, ERK-1, ERK-2, cPLA2, and NF-κB in liver tissues of rats among six groups were detected by RT-qPCR and western blotting. ELISA was used to determine serum levels of IL-1ß, IL-10, TNF-α, procalcitonin (PCT), and C-reactive protein (CRP). Pearson correlation analysis was conducted to measure correlations. Cell apoptosis of rats among six groups was detected by Tunel staining. The expressions of S100A12, ERK-1, ERK-2, cPLA2, and NF-κB decreased in the S100A12 siRNA group while increased in the EGF group compared with the model group. S100A12 mRNA expression was positively correlated with mRNA expressions of related genes in the ERK signaling pathway (ERK-1, ERK-2, cPLA2, and NF-κB) in the model and empty vector groups. Expressions of IL-1ß, IL-6, TNF-α, PCT, and CRP in the EGF group were higher than those in the model group, but were lower than those in the S100A12 siRNA group. Compared with the model group, cell apoptosis decreased in the S100A12 siRNA group but that increased in the EGF group. We demonstrates that S100A12 gene silencing decreases serum levels of anti-inflammatory/pro-inflammatory cytokines in septic rats by inhibiting the ERK signaling pathway.

Effect of short-term liver X receptor activation on epidermal barrier features in mild to moderate atopic dermatitis: A randomized controlled trial.

BACKGROUND: Liver X receptors (LXRs) are involved in maintaining epidermal barrier and suppressing inflammatory responses in model systems. The LXR agonist VTP-38543 showed promising results in improving barrier function and inflammatory responses in model systems. OBJECTIVE: To assess the safety, tolerability, cellular and molecular changes, and clinical efficacy of the topical VTP-38543 in adults with mild to moderate atopic dermatitis (AD). METHODS: A total of 104 ambulatory patients with mild to moderate AD were enrolled in this randomized, double-blind, vehicle-controlled trial between December 2015 and September 2016. VTP-38543 cream in 3 concentrations (0.05%, 0.15%, and 1.0%) or placebo was applied twice daily for 28 days. Pretreatment and posttreatment skin biopsy specimens were obtained from a subset of 33 patients. Changes in SCORing of Atopic Dermatitis, Eczema Area and Severity Index, Investigator's Global Assessment, and tissue biomarkers (by real-time polymerase chain reaction and immunostaining) were evaluated. RESULTS: Topical VTP-38543 was safe and well tolerated. VTP-38543 significantly increased messenger RNA (mRNA) expression of epidermal barrier differentiation (loricrin and filaggrin, P = .02) and lipid (adenosine triphosphate-binding cassette subfamily G member 1 and sterol regulatory element binding protein 1c, P < .01) measures and reduced epidermal hyperplasia markers (thickness, keratin 16 mRNA). VTP-38543 nonsignificantly suppressed cellular infiltrates and down-regulated mRNA expression of several TH17/TH22-related (phosphatidylinositol 3, S100 calcium-binding protein A12) and innate immunity (interleukin 6) markers. CONCLUSION: Topical VTP-38543 is safe and well tolerated. Its application led to improvement in barrier differentiation and lipids. Longer-term studies are needed to clarify whether a barrier-based approach can induce meaningful suppression of immune abnormalities. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT02655679.

Insights into binding of S100 proteins to scavenger receptors: class B scavenger receptor CD36 binds S100A12 with high affinity.

The EF-hand type calcium-binding protein S100A12 exerts numerous intra- and extracellular functions of (patho)physiological relevance. Therefore, receptors of S100A12 are of high interest for research and clinical applications. Beside the extensively studied receptor for advanced glycation endproducts (RAGE), G-protein coupled receptors and more recently, scavenger receptors are suggested to be putative S100A12 receptors. Own findings and further information from the literature predestined CD36, a class B scavenger receptor, as promising candidate. To substantiate or prove against this hypothesis, this study aimed at investigation of interaction of S100A12 and CD36 on molecular and cellular level by the use of surface plasmon resonance (SPR), radio- and fluorescence-tracer-based cell binding, and cell activation experiments. S100A12 revealed binding affinity to CD36 in the low nanomolar range, essentially, at the CD36 thrombospondin-1 binding site. Additionally, S100A12-mediated translocation of CD36 to the membrane and elevation of both CD36 and peroxisome proliferator-activated receptor γ (PPARγ) expression was observed, which suggest a potential regulatory function of S100A12-CD36 interaction.

Molecular Mechanisms of Mild and Severe Pneumonia: Insights from RNA Sequencing.

BACKGROUND This study aimed to uncover the molecular mechanisms underlying mild and severe pneumonia by use of mRNA sequencing (RNA-seq). MATERIAL AND METHODS RNA was extracted from the peripheral blood of patients with mild pneumonia, severe pneumonia, and healthy controls. Sequencing was performed on the HiSeq4000 platform. After filtering, clean reads were mapped to the human reference genome hg19. Differentially expressed genes (DEGs) were identified between the control group and the mild or severe group. A transcription factor-gene network was constructed for each group. Biological process (BP) terms enriched by DEGs in the network were analyzed and these genes were also mapped to the Connectivity map to search for small-molecule drugs. RESULTS A total of 199 and 560 DEGs were identified from the mild group and severe group, respectively. A transcription factor-gene network consisting of 215 nodes and another network consisting of 451 nodes were constructed in the mild group and severe group, respectively, and 54 DEGs (e.g., S100A9 and S100A12) were found to be common, with consistent differential expression changes in the 2 groups. Genes in the transcription factor-gene network for the mild group were mainly enriched in 13 BP terms, especially defense and inflammatory response (e.g., S100A8) and spermatogenesis, while the top BP terms enriched by genes in the severe group include response to oxidative stress (CCL5), wound healing, and regulation of cell differentiation (CCL5), and of the cellular protein metabolic process. CONCLUSIONS S100A9 and S100A12 may have a role in the pathogenesis of pneumonia: S100A9 and CXCL1 may contribute solely in mild pneumonia, and CCL5 and CXCL11 may contribute in severe pneumonia.

Expression and clinical implication of S100A12 in gastric carcinoma.

S100 protein family has been implicated in multiple stages of tumorigenesis and progression in which S100A12 is one of the subtypes. However, the role of S100A12 in gastric carcinoma (GC) has not been elucidated yet. This study was aimed to investigate the expression of S100A12 in GC tissues and evaluate the clinical significance of S100A12 in GC patients. S100A12 protein was detected in 207 GC and 52 paired non-cancerous mucosal tissues by immunohistochemistry, while messenger RNA (mRNA) was investigated by Oncomine database analysis. Moreover, survival analysis was performed and the correlation between S100A12 and ubiquitin-specific protease 10 (USP10) and p53 was determined. As for tumor cells, the expression of S100A12 protein and mRNA in GC was proved to be lower than that in non-cancerous mucosa tissues (p < 0.05). Clinicopathological analysis showed that S100A12 protein was negatively associated with tumor size (p = 0.004), depth of invasion (p = 0.022), tumor node metastasis (TNM) stage (p = 0.018), Lauren classification (p < 0.000), and cell differentiation (p < 0.000). In contrast, a positive correlation was found between S100A12 and USP10 protein (p < 0.000). However, no relationship was detected between S100A12 and p53. Moreover, the survival analysis indicated that S100A12 protein was a favorable factor of prognosis of GC (p < 0.05). Although the expression of S100A12 in the stromal cells was detected higher than that in the tumor cells, no relationship between S100A12 protein in stromal cells and the clinicopathological features described above was found (p > 0.05). Our findings suggested that low expression of S100A12 might be served as a new marker in the tumorigenesis and progression of GC.

S100A12 and the S100/Calgranulins: Emerging Biomarkers for Atherosclerosis and Possibly Therapeutic Targets.

Atherosclerosis is mediated by local and systematic inflammation. The multiligand receptor for advanced glycation end products (RAGE) has been studied in animals and humans and is an important mediator of inflammation and atherosclerosis. This review focuses on S100/calgranulin proteins (S100A8, S100A9, and S100A12) and their receptor RAGE in mediating vascular inflammation. Mice lack the gene for S100A12, which in humans is located on chromosome 3 between S100A8 and S100A9. Transgenic mice with smooth muscle cell-targeted expression of S100A12 demonstrate increased coronary and aortic calcification, as well as increased plaque vulnerability. Serum S100A12 has recently been shown to predict future cardiovascular events in a longitudinal population study, underscoring a role for S100A12 as a potential biomarker for coronary artery disease. Genetic ablation of S100A9 or RAGE in atherosclerosis-susceptible apolipoprotein E null mice results in reduced atherosclerosis. Importantly, S100A12 and the RAGE axis can be modified pharmacologically. For example, soluble RAGE reduces murine atherosclerosis and vascular inflammation. Additionally, a class of compounds currently in phase III clinical trials for multiple sclerosis and rheumatologic conditions, the quinoline-3-carboxamides, reduce atherosclerotic plaque burden and complexity in transgenic S100A12 apolipoprotein E null mice, but have not been tested with regards to human atherosclerosis. The RAGE axis is an important mediator for inflammation-induced atherosclerosis, and S100A12 has emerged as biomarker for human atherosclerosis. Decreasing inflammation by inhibiting S100/calgranulin-mediated activation of RAGE attenuates murine atherosclerosis, and future studies in patients with coronary artery disease are warranted to confirm S100/RAGE as therapeutic target for atherosclerosis.

Interferon-ß 1a Modulates Expression of RAGE but Not S100A12 and Nuclear Factor-κB in Multiple Sclerosis Patients.

OBJECTIVES: Interferon-ß 1a (IFN-ß 1a) is a common strategy therapy for multiple sclerosis (MS) with unknown mechanisms. S100A12 (S100 calcium-binding protein A12) is a damage-associated molecular pattern molecule which binds to its receptor, RAGE (receptor for advanced glycation end products), and activates nuclear factor-κB (NF-κB). NF-κB is transcribed from proinflammatory molecules, which may participate in the pathogenesis of MS. Therefore, the aims of this study were to compare mRNA levels of S100A12, RAGE, and NF-κB in newly diagnosed MS patients with healthy controls and determine whether IFN-ß 1a therapy affects the expression of the molecules. METHODS: S100A12, RAGE, and NF-κB mRNA levels in 30 new cases of untreated MS patients and 35 healthy controls were evaluated using the real-time PCR technique. The mRNA levels were also evaluated in the MS patients after 6 months of IFN-ß 1a therapy. RESULTS: S100A12, RAGE, and NF-κB mRNA levels were significantly decreased in the new cases of untreated MS patients in comparison to healthy controls. IFN-ß 1a therapy results in upregulation of RAGE in MS patients, but not S100A12 and NF-κB. CONCLUSIONS: It appears that S100A12 participates in the pathogenesis of MS, and it seems that IFN-ß 1a modulates immune responses in an S100A12-independent manner. Based on the reported anti-inflammatory effects of RAGE, it seems that RAGE may be considered as a mechanism by IFN-ß 1a to modulate immune responses. NF-κB is produced permanently in the human cells and is inactive in the cytoplasm; therefore, the effects of IFN-ß 1a may be related to its functions rather than expressions.