S100A12 Expression Is Modulated During Monocyte Differentiation and Reflects Periodontitis Severity.

S100A12 is a calcium-binding protein of the S100 subfamily of myeloid-related proteins that acts as an alarmin to induce a pro-inflammatory innate immune response. It has been linked to several chronic inflammatory diseases, however its role in the common oral immunopathology periodontitis is largely unknown. Previous in vitro monoculture experiments indicate that S100A12 production decreases during monocyte differentiation stages, while the regulation within tissue is poorly defined. This study evaluated S100A12 expression in monocyte subsets, during monocyte-to-macrophage differentiation and following polarization, both in monoculture and in a tissue context, utilizing a three-dimensional co-culture oral tissue model. Further, we explored the involvement of S100A12 in periodontitis by analyzing its expression in peripheral circulation and gingival tissue, as well as in saliva. We found that S100A12 expression was higher in classical than in non-classical monocytes. S100A12 expression and protein secretion declined significantly during monocyte-to-macrophage differentiation, while polarization of monocyte-derived macrophages had no effect on either. Peripheral monocytes from periodontitis patients had higher S100A12 expression than monocytes from controls, a difference particularly observed in the intermediate and non-classical monocyte subsets. Further, monocytes from periodontitis patients displayed an increased secretion of S100A12 compared with monocytes from controls. In oral tissue cultures, monocyte differentiation resulted in increased S100A12 secretion over time, which further increased after inflammatory stimuli. Likewise, S100A12 expression was higher in gingival tissue from periodontitis patients where monocyte-derived cells exhibited higher expression of S100A12 in comparison to non-periodontitis tissue. In line with our findings, patients with severe periodontitis had significantly higher levels of S100A12 in saliva compared to non-periodontitis patients, and the levels correlated to clinical periodontal parameters. Taken together, S100A12 is predominantly secreted by monocytes rather than by monocyte-derived cells. Moreover, S100A12 is increased in inflamed tissue cultures, potentially as a result of enhanced production by monocyte-derived cells. This study implicates the involvement of S100A12 in periodontitis pathogenesis, as evidenced by increased S100A12 expression in inflamed gingival tissue, which may be due to altered circulatory monocytes in periodontitis.

Expression of colony-stimulating factor 1 and interleukin-34 in gingival tissue and gingival fibroblasts from periodontitis patients and controls.

BACKGROUND: Colony-stimulating factor 1 (CSF-1) and interleukin (IL)-34 are important for the functions of myeloid lineage cells and are involved in several chronic inflammatory conditions associated with tissue degeneration. The aim of this study is to evaluate the expression of CSF-1 and IL-34 in gingival tissue and gingival fibroblasts (GF) from patients with periodontitis and controls. METHODS: Gingival biopsies were obtained from 19 periodontitis patients and 15 controls. Expression of CSF-1 and IL-34 in gingival tissue was assessed by western blot and localization by immunohistochemistry. Expression of CSF1 and IL34 mRNA in GF was analyzed by real-time polymerase chain reaction and protein expression visualized by immunofluorescence stainings. CSF-1 and IL-34 secretion from GF was evaluated in response to tumor necrosis factor-alpha (TNF-α), IL-1ß, Escherichia coli lipopolysaccharide (Ec-LPS) and Porphyromonas gingivalis lipopolysaccharide (Pg-LPS) stimulation, using enzyme-linked immunosorbent assays. RESULTS: CSF-1 was increased in gingival tissue from periodontitis patients compared with controls (P < 0.05) whereas IL-34 expression was similar. In GF from a non-periodontitis donor, stimulation with either TNF-α, IL-1ß, Ec-LPS, or Pg-LPS, increased the secretion of CSF-1 (P < 0.05) and Ec-LPS stimulation increased IL-34 (P < 0.05). CSF-1 and IL-34 were expressed and secreted constitutively from GF, with comparable levels in GF from periodontitis patients and controls. Inflammatory stimuli increased the secretion of CSF-1 and IL-34 with comparable levels measured from GF from periodontitis patients and controls (P < 0.05). CONCLUSION: The expression of CSF-1 and IL-34 in gingival tissue and fibroblasts suggests involvement in myeloid cell functions during periodontal inflammation.

MMP-12 and S100s in saliva reflect different aspects of periodontal inflammation.

Matrix metalloproteinase (MMP)-12, S100A8/A9, and S100A12 are involved in innate immune responses. We addressed whether different aspects of oral health and non-disease-related covariates influence their levels in saliva. 436 participants were clinically examined, completed a health questionnaire, and provided stimulated saliva. Salivary levels of MMP-12, S100A8/A9, and S100A12 were determined by enzyme-linked immunosorbent assays. Lower MMP-12 levels were observed in individuals 40-64 years old (yo) compared to < 40 yo, and higher S100A8/A9 levels were found in individuals > 64 yo compared to 40-64 yo. Smokers exhibited lower MMP-12 and S100A12 levels compared to non-smokers. All three proteins were elevated in individuals with bleeding on probing (BOP) > 20% compared to those with BOP ≤ 20%, and the S100A8/A9 levels were higher in individuals having ≥ 10% gingival pocket depths (PPD) ≥ 4 mm compared to the ones with shallow pockets < 4 mm. The extent of alveolar bone loss or presence of manifest caries did not alter any of the markers. MMP-12, S100A8/A9, and S100A12 levels were higher in participants with high periodontal inflammatory burden. All three proteins correlated positively to BOP, PPD, and to several inflammatory mediators. The explanatory variables for MMP-12 in saliva were age, smoking, presence of any tumor, and percentage of PPD ≥ 4 mm. The determinant of salivary S100A8/A9 was percentage of BOP, while S100A12 levels were associated with percentage of BOP and presence of any tumor. Taken together, MMP-12 and the S100/calgranulin levels in saliva reflect different aspects of periodontal inflammation. Smoking and age should be taken into account in further investigation of these proteins as biomarker candidates of periodontal disease.

Gingival Tissue Inflammation Promotes Increased Matrix Metalloproteinase-12 Production by CD200Rlow Monocyte-Derived Cells in Periodontitis.

Irreversible tissue recession in chronic inflammatory diseases is associated with dysregulated immune activation and production of tissue degradative enzymes. In this study, we identified elevated levels of matrix metalloproteinase (MMP)-12 in gingival tissue of patients with the chronic inflammatory disease periodontitis (PD). The source of MMP12 was cells of monocyte origin as determined by the expression of CD14, CD68, and CD64. These MMP12-producing cells showed reduced surface levels of the coinhibitory molecule CD200R. Similarly, establishing a multicellular three-dimensional model of human oral mucosa with induced inflammation promoted MMP12 production and reduced CD200R surface expression by monocyte-derived cells. MMP12 production by monocyte-derived cells was induced by CSF2 rather than the cyclooxygenase-2 pathway, and treatment of monocyte-derived cells with a CD200R ligand reduced CSF2-induced MMP12 production. Further, MMP12-mediated degradation of the extracellular matrix proteins tropoelastin and fibronectin in the tissue model coincided with a loss of Ki-67, a protein strictly associated with cell proliferation. Reduced amounts of tropoelastin were confirmed in gingival tissue from PD patients. Thus, this novel association of the CD200/CD200R pathway with MMP12 production by monocyte-derived cells may play a key role in PD progression and will be important to take into consideration in the development of future strategies to diagnose, treat, and prevent PD.

Systemic Chemokine Levels with "Gut-Specific" Vedolizumab in Patients with Inflammatory Bowel Disease-A Pilot Study.

Vedolizumab, a gut-specific biological treatment for inflammatory bowel disease (IBD), is an antibody that binds to the α4ß7 integrin and blocks T-cell migration into intestinal mucosa. We aimed to investigate chemokine levels in serum of IBD-patients treated with vedolizumab. In this pilot study, we included 11 IBD patients (8 Crohn's disease, 3 ulcerative colitis) previously non-respondent to anti-tumor necrosis factor (TNF)-agents. Patients received vedolizumab at week 0, 2 and 6 and were evaluated for clinical efficacy at week 10. Clinical characteristics and routine laboratory parameters were obtained and patients were classified as responders or non-responders. Expression of 21 chemokines in serum was measured using Proximity Extension Assay and related to clinical outcome. At week 10, 6 out of 11 patients had clinically responded. Overall expression of CCL13 increased after treatment. In non-responders, expression of CCL13 and CXCL8 increased after treatment, and CCL20 and CXCL1 expressions were higher compared to responders. In responders, CCL28 decreased after treatment. C-reactive protein (CRP) correlated negatively with 6 chemokines before therapy, but not after therapy. Systemic CCL13 expression increases in IBD-patients after vedolizumab therapy and several chemokine levels differ between responders and non-responders. An increased CCL13-level when starting vedolizumab treatment, might indicate potential prognostic value of measuring chemokine levels when starting therapy with vedolizumab. This study provides new information on modulation of systemic chemokine levels after vedolizumab treatment.

Th17 micro-milieu regulates NLRP1-dependent caspase-5 activity in skin autoinflammation.

IL-1ß is a potent player in cutaneous inflammation and central for the development of a Th17 micro-milieu in autoinflammatory diseases including psoriasis. Its production is controlled at the transcriptional level and by subsequent posttranslational processing via inflammatory caspases. In this study, we detected inflammatory caspase-5 active in epidermal keratinocytes and in psoriatic skin lesions. Further, interferon-γ and interleukin-17A synergistically induced caspase-5 expression in cultured keratinocytes, which was dependent on the antimicrobial peptide psoriasin (S100A7). However, diseases-relevant triggers for caspase-5 activity and IL-1ß production remain unknown. Recently, extranuclear DNA has been identified as danger-signals abundant in the psoriatic epidermis. Here, we could demonstrate that cytosolic double-stranded (ds) DNA transfected into keratinocytes triggered the activation of caspase-5 and the release of IL-1ß. Further, interleukin-17A promoted caspase-5 function via facilitation of the NLRP1-inflammasome. Anti-inflammatory vitamin D interfered with the IL-1ß release and suppressed caspase-5 in keratinocytes and in psoriatic skin lesions. Our data link the disease-intrinsic danger signals psoriasin (S100A7) and dsDNA for NLPR1-dependent caspase-5 activity in psoriasis providing potential therapeutic targets in Th17-mediated skin autoinflammation.

Receptor-Type Protein-Tyrosine Phosphatase ζ and Colony Stimulating Factor-1 Receptor in the Intestine: Cellular Expression and Cytokine- and Chemokine Responses by Interleukin-34 and Colony Stimulating Factor-1.

Differential intestinal expression of the macrophage growth factors colony stimulating factor-1 (CSF-1), interleukin (IL)-34, and their shared CSF-1 receptor (CSF-1R) in inflammatory bowel disease (IBD) has been shown. Diverse expression between CSF-1 and IL-34, suggest that IL-34 may signal via an alternate receptor. Receptor-type protein-tyrosine phosphatase ζ (PTPRZ1, RPTP-ζ), an additional IL-34 receptor, was recently identified. Here, we aimed to assess PTPRZ1 expression in IBD and non-IBD intestinal biopsies. Further, we aimed to investigate cellular PTPRZ1 and CSF-1R expression, and cytokine- and chemokine responses by IL-34 and CSF-1. The expression of PTPRZ1 was higher in non-IBD colon compared to ileum. PTPRZ1 expression was not altered with inflammation in IBD, however, correlated to IL34, CSF1, and CSF1R. The expression patterns of PTPRZ1 and CSF-1R differed in peripheral blood mononuclear cells (PBMCs), monocytes, macrophages, and intestinal epithelial cell line. PBMCs and monocytes of the same donors responded differently to IL-34 and CSF-1 with altered expression of tumor-necrosis factor α (TNF-α), IL-1ß, interferon γ (IFN-γ), IL-13, IL-8, and monocyte chemotactic protein-1 (MCP-1) levels. This study shows that PTPRZ1 was expressed in bowel tissue. Furthermore, CSF-1R protein was detected in an intestinal epithelial cell line and donor dependently in primary PBMCs, monocytes, and macrophages, and first hints also suggest an expression in these cells for PTPRZ1, which may mediate IL-34 and CSF-1 actions.

Increased Eotaxin and MCP-1 Levels in Serum from Individuals with Periodontitis and in Human Gingival Fibroblasts Exposed to Pro-Inflammatory Cytokines.

Periodontitis is a chronic inflammatory disease of tooth supporting tissues resulting in periodontal tissue destruction, which may ultimately lead to tooth loss. The disease is characterized by continuous leukocyte infiltration, likely mediated by local chemokine production but the pathogenic mechanisms are not fully elucidated. There are no reliable serologic biomarkers for the diagnosis of periodontitis, which is today based solely on the degree of local tissue destruction, and there is no available biological treatment tool. Prompted by the increasing interest in periodontitis and systemic inflammatory mediators we mapped serum cytokine and chemokine levels from periodontitis subjects and healthy controls. We used multivariate partial least squares (PLS) modeling and identified monocyte chemoattractant protein-1 (MCP-1) and eotaxin as clearly associated with periodontitis along with C-reactive protein (CRP), years of smoking and age, whereas the number of remaining teeth was associated with being healthy. Moreover, body mass index correlated significantly with serum MCP-1 and CRP, but not with eotaxin. We detected higher MCP-1 protein levels in inflamed gingival connective tissue compared to healthy but the eotaxin levels were undetectable. Primary human gingival fibroblasts displayed strongly increased expression of MCP-1 and eotaxin mRNA and protein when challenged with tumor necrosis factor-α (TNF-α and interleukin-1ß (IL-1ß), key mediators of periodontal inflammation. We also demonstrated that the upregulated chemokine expression was dependent on the NF-κΒ pathway. In summary, we identify higher levels of CRP, eotaxin and MCP-1 in serum of periodontitis patients. This, together with our finding that both CRP and MCP-1 correlates with BMI points towards an increased systemic inflammatory load in patients with periodontitis and high BMI. Targeting eotaxin and MCP-1 in periodontitis may result in reduced leukocyte infiltration and inflammation in periodontitis and maybe prevent tooth loss.

Leukocyte-derived koebnerisin (S100A15) and psoriasin (S100A7) are systemic mediators of inflammation in psoriasis.

BACKGROUND: Psoriasis is a systemic immune-mediated chronic inflammatory disease. In the skin, the antimicrobial proteins koebnerisin (S100A15) and psoriasin (S100A7) are overexpressed in the epidermis of psoriatic lesions and mediate inflammation as chemoattractants for immune cells. Their role for systemic inflammation in circulating leukocytes is unknown. OBJECTIVE: The aim of the study was to identify circulating leukocyte populations as a source of koebnerisin and psoriasin. Further, immune-stimulatory effects of these S100A proteins on circulating leukocytes were evaluated and their role as therapeutic response markers in patients with psoriasis was analyzed upon UVB treatment. METHODS: The expression and production of koebnerisin and psoriasin by leukocytes were assessed by quantitative real-time PCR (qRT-PCR) and immunoblotting. The S100A protein mediated regulation of proinflammatory cytokines by peripheral blood mononuclear cells (PBMCs) was measured with qRT-PCR and cytometric bead assay. RESULTS: We identified circulating leukocytes as novel sources of koebnerisin (S100A15) and psoriasin (S100A7). Circulating leukocytes (PBMCs) of patients with psoriasis produced increased levels of koebnerisin and psoriasin compared to healthy individuals. Both S100A proteins further acted as 'alarmins' on PBMC to induce proinflammatory cytokines implicated in the pathogenesis of psoriasis, such as IL-1ß, TNF-α, IL-6 and IL-8. Koebnerisin levels were suppressed in PBMC of psoriatic patients when effectively treated with narrow-band UVB. CONCLUSIONS: Data suggest that koebnerisin and psoriasin are systemic pro-inflammatory mediators and koebnerisin acts as a therapeutic response marker in psoriasis.

Interleukin 34: a new modulator of human and experimental inflammatory bowel disease.

IBD (inflammatory bowel disease), where CD (Crohn's disease) and UC (ulcerative colitis) represent the two main forms, are chronic inflammatory conditions of the intestine. Macrophages play a central role in IBD pathogenesis and are regulated by major differentiation factors such as CSF-1 (colony-stimulating factor 1) in homoeostasis and inflammation. IL (interleukin)-34 has recently been discovered as a second ligand for CSF-1R (CSF-1 receptor). However, expression and involvement of IL-34 in IBD remain unknown. In the present paper, we investigated the expression of IL34, CSF1 and their shared receptor CSF1R in normal human ileum and colon, in inflamed and non-inflamed tissues of CD and UC patients, and in a mouse model of experimental colitis. We found distinct expression patterns of IL34 and CSF1 in ileum and colon, with higher IL34 in ileum and, in contrast, higher CSF1 in colon. Furthermore, IL34 and CSF1 expression was increased with inflammation in IBD patients and in experimental colitis. In humans, infiltrating cells of the lamina propria and intestinal epithelial cells expressed IL-34, and TNF-α (tumour necrosis factor α) regulated IL-34 expression in intestinal epithelial cells through the NF-κB (nuclear factor κB) pathway. These data demonstrate the expression pattern of IL-34 in ileum and colon and suggest IL-34 as a new modulator of inflammation in IBD.

Melatonin compensates silencing of heat shock protein 70 and suppresses ultraviolet radiation-induced inflammation in human skin ex vivo and cultured keratinocytes.

Melatonin, a lipophilic compound synthesized and released from the pineal gland, effectively acts against ultraviolet radiation (UVR), one of the main inducers of epidermal damage, skin cancer, inflammation, and DNA photo damage. One of the common known stress protein induced by UVR is heat shock protein 70 (Hsp70), highly expressed in human keratinocytes, providing cellular resistance to such stressors. Here, using human full-thickness skin and normal human epidermal keratinocytes (NHEK), we investigated the interaction of melatonin and Hsp70 toward UVR-induced inflammatory and apoptotic responses. The following observations were made: (i) UVR upregulated Hsp70 gene expression in human epidermis while melatonin significantly inverted this effect, (ii) similar patterns of regulation were observed within Hsp70 protein level, and (iii) mechanistic studies involving silencing of Hsp70 RNA (Hsp70 siRNA) showed prominent decrease of IκB-α (an inhibitor of NF-κB) and enhanced gene expression of pro-inflammatory cytokines (IL-1ß, IL-6, Casp-1) and pro-apoptotic protein (Casp-3) in NHEK. Parallel investigation using melatonin (10(-3)  m) significantly inverted these responses regardless depletion of Hsp70 RNA suggesting a compensatory action of this compound in the defense mechanisms. Our findings combined with data reported so far thus enrich existing knowledge about the potent anti-apoptotic and anti-inflammatory action of melatonin.

The antimicrobial peptides psoriasin (S100A7) and koebnerisin (S100A15) suppress extracellular matrix production and proliferation of human fibroblasts.

BACKGROUND/AIMS: Keloids result from aberrations in the normal wound healing cascade and can lead to pruritus, contractures and pain. The underlying mechanisms of excessive scarring are not yet understood, and most therapeutic strategies remain unsatisfactory. Psoriasin (S100A7) and koebnerisin (S100A15) are released by keratinocytes during physiological wound healing. We found S100 production is markedly decreased in keloid scar tissue. The disturbed epidermal S100 expression might contribute to keloid formation; thus, we studied their effect on dermal fibroblasts and extracellular matrix (ECM) production. METHODS: S100 peptides, ECM regulation and distribution were analysed in normal and keloid tissue by quantitative PCR (qPCR), immunoblotting and immunofluorescent staining. Isolated dermal fibroblasts were incubated with S100 proteins, and the regulation of ECM and transforming growth factor (TGF)-ß was determined using qPCR. Fibroblast proliferation and viability were determined by the 5-bromo-2'-deoxyuridine assay and crystal violet assay. RESULTS: Keloid tissue featured a pronounced expression of ECMs, such as collagen types 1 and 3, whereas the production of psoriasin and koebnerisin was markedly decreased in keloid-derived cells and keloid tissue. Both S100 proteins inhibited the expression of collagens, fibronectin-1, α-smooth-muscle actin and TGF-ß by fibroblasts. Further, they also suppressed fibroblast proliferation. CONCLUSION: Psoriasin and koebnerisin show antifibrotic effects and may lead to novel preventive and therapeutic strategies for fibroproliferative diseases.

Isotretinoin therapy changes the expression of antimicrobial peptides in acne vulgaris.

In acne vulgaris, antimicrobial peptides (AMPs) could play a dual role; i.e., protective by acting against Propionibacterium acnes, pro-inflammatory by acting as signalling molecules. The cutaneous expression of 15 different AMPs was investigated in acne patients; furthermore, the impact of isotretinoin therapy on AMP expression was analysed in skin biopsies from 13 patients with acne vulgaris taken before, during and after a 6-month treatment cycle with isotretinoin using quantitative real-time polymerase chain reaction. Cutaneous expression of the AMPs cathelicidin, human ß-defensin-2 (HBD-2), lactoferrin, lysozyme, psoriasin (S100A7), koebnerisin (S100A15), and RNase 7 was upregulated in untreated acne vulgaris, whereas α-defensin-1 (HNP-1) was downregulated compared to controls. While relative expression levels of cathelicidin, HBD-2, lactoferrin, psoriasin (S100A7), and koebnerisin (S100A15) decreased during isotretinoin treatment, only those of cathelicidin and koebnerisin returned to normal after 6 months of isotretinoin therapy. The increased expression of lysozyme and RNase 7 remained unaffected by isotretinoin treatment. The levels of granulysin, RANTES (CCL5), perforin, CXCL9, substance P, chromogranin B, and dermcidin were not regulated in untreated acne patients and isotretinoin had no effect on these AMPs. In conclusion, the expression of various AMPs is altered in acne vulgaris. Isotretinoin therapy normalizes the cutaneous production of distinct AMPs while the expression of others is still increased in healing acne. Considering the antimicrobial and pro-inflammatory role of AMPs, these molecules could serve as specific targets for acne therapy and maintenance of clinical remission.

Opposing functions of psoriasin (S100A7) and koebnerisin (S100A15) in epithelial carcinogenesis.

The S100 protein family is involved in epithelial cell maturation and inflammation. Some S100 members are dysregulated during carcinogenesis and have been established as tumor markers. Psoriasin (S100A7) and koebnerisin (S100A15) are highly homologous proteins that have been first described in psoriasis, which is characterized by disturbed epidermal maturation and chronic inflammation. Despite their homology, both S100 proteins are distinct in expression and function through different receptors but synergize as chemoattractants and pro-inflammatory 'alarmins' to promote inflammation. Psoriasin and koebnerisin are further regulated with tumor progression in epithelial cancers. In tumor cells, high cytoplasmic expression of psoriasin and koebnerisin may prevent oncogenic activity, whereas their nuclear translocation and extracellular secretion are associated with tumor progression and poor prognosis. The present review outlines these opposing effects of psoriasin and koebnerisin in multifunctional pathways and mechanisms that are known to affect tumor cells ('seeds'), tumor environment ('soil') and tumor cell metastasis ('seeding') thereby influencing epithelial carcinogenesis.

Vitamin D analog calcipotriol suppresses the Th17 cytokine-induced proinflammatory S100 "alarmins" psoriasin (S100A7) and koebnerisin (S100A15) in psoriasis.

The antimicrobial peptides (AMP) psoriasin (S100A7) and koebnerisin (S100A15) are differently induced in psoriatic skin. They act synergistically as chemoattractants and "alarmins" to amplify inflammation in psoriasis. Th17 cytokines are key players in psoriasis pathogenesis and vitamin D analogs feature anti-psoriatic effects; both of these activities could be mediated through epidermal AMP regulation. We show that supernatants of cultured psoriatic T cells induce and release psoriasin and koebnerisin from keratinocytes and the Th17 cytokines IL-17A, tumor necrosis factor-α, and IL-22 differently regulate psoriasin and koebnerisin reflecting their distinct expression pattern in normal and psoriatic skin. IL-17A is the principal inducer of both S100 and their expression is further amplified by cooperating Th17 cytokines in the micromilieu of psoriatic skin. Increased extracellular psoriasin and koebnerisin also synergize as "alarmins" to prime epidermal keratinocytes for production of immunotropic cytokines that further amplify the inflammatory response. Treatment of psoriatic plaques with the vitamin D analog calcipotriol interferes with the S100-mediated positive feedback loop by suppressing the increased production of psoriasin and koebnerisin in psoriatic skin and their Th17-mediated regulation in epidermal keratinocytes. Thus, targeting the S100-amplification loop could be a beneficial anti-inflammatory approach in psoriasis and other inflammatory skin diseases.