| 1. |
- Aidoukovitch, Alexandra, et al.
(författare)
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Antimicrobial peptide LL-37 and its pro-form, hCAP18, in desquamated epithelial cells of human whole saliva
- 2020
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Ingår i: European Journal of Oral Sciences. - : Wiley. - 0909-8836 .- 1600-0722. ; 128:1, s. 1-6
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Tidskriftsartikel (refereegranskat)abstract
- The antimicrobial peptide LL-37 is active against oral bacteria and has been demonstrated to be present in human saliva, but its distribution in different fractions of saliva is not known. LL-37 is formed from its intracellular pro-form, hCAP18, in an extracellular enzymatic reaction catalyzed by proteinase 3 and kallikrein 5. Here, we prepared cell-containing and cell-free fractions of unstimulated human whole saliva by centrifugation after depolymerization of mucins with dithiothreitol, and measured the levels of hCAP18/LL-37 in these fractions using ELISA. Cellular expression of hCAP18/LL-37 was determined by western blotting and immunocytochemistry. The ELISA analyses demonstrated that both cells and cell-free saliva contained hCAP18/LL-37. Western blot analysis of cell-pellet homogenates showed a strong band corresponding to hCAP18 at the correct molecular weight and a weak band corresponding to LL-37. Phase-contrast and light microscopy revealed that the cells consisted of desquamated epithelial cells. These cells expressed cytoplasmic immunoreactivity for hCAP18/LL-37. The peripheral part of the cytoplasm, corresponding to the plasma membrane, was particularly rich in hCAP18/LL-37 immunoreactivity. No immunoreactivity was observed after omission of the primary antibody. We conclude that desquamated epithelial cells of human whole saliva contain antimicrobial hCAP18/LL-37, suggesting that these cells may take part in the innate immune system by harboring and releasing these peptides.
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| 2. |
- Aidoukovitch, Alexandra, et al.
(författare)
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Desquamated Epithelial Cells of Unstimulated Human Whole Saliva Express Both EGF Transcript and Protein
- 2022
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Ingår i: International Journal of Dentistry. - : Hindawi Limited. - 1687-8728 .- 1687-8736. ; 2022, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The aim of this study was to investigate if desquamated oral epithelial cells (DOECs) express the epidermal growth factor (EGF) and if these cells thereby may contribute to salivary EGF contents.BACKGROUND: DOECs have recently been shown to harbor the antimicrobial peptide LL-37, proposing that they may also store other biologically important salivary peptides/proteins. The EGF peptide is a growth factor which plays a critical role to maintain epithelial integrity and promote epithelial healing. The EGF is produced by salivary glands, but it is not known whether DOECs contain the EGF and thereby contribute to salivary EGF levels.MATERIALS AND METHODS: DOECs were isolated from unstimulated whole saliva collected from four healthy volunteers. EGF protein expression was determined in cell lysates by dot blot and ELISA. Cellular distribution of cytokeratin, the proliferation marker Ki67, and EGF immunoreactivity were assessed by immunocytochemistry. EGF gene expression was investigated by qPCR. Expression of EGF transcript and protein in DOECs was compared to that in the human cultured keratinocyte cell line (HaCaT) cells.RESULTS: EGF protein expression was detected in DOEC cell lysates by both dot blot and ELISA. Strong cytoplasmic EGF immunoreactivity was observed in DOECs, although some cells showed only a weak immunoreactive signal for EGF. Moreover, DOECs, besides containing EGF protein, also expressed transcript for EGF. Interestingly, ELISA analysis revealed that EGF protein contents were higher in DOECs than in HaCaT cells. ELISA analysis also disclosed that EGF concentration was about 10 times higher in whole saliva compared to DOECs. EGF transcript expression was about 50% lower in HaCaT cells stimulated with high (10%) compared to low (0.1%) concentration of fetal bovine serum, representing growth-stimulated and growth-restricted conditions, respectively, implying that growth-stimulus exerts negative feedback on EGF gene activity in HaCaT cells.CONCLUSION: Here, we show for the first time that DOECs express the EGF, arguing that these cells contribute to salivary EGF contents and hence may play a role in gingival epithelial repair and wound healing.
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| 3. |
- Aidoukovitch, Alexandra, et al.
(författare)
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Exogenous LL-37 but not homogenates of desquamated oral epithelial cells shows activity against Streptococcus mutans
- 2021
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Ingår i: Acta Odontologica Scandinavica. - : Informa UK Limited. - 0001-6357 .- 1502-3850. ; 79:6, s. 466-472
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The antimicrobial peptide hCAP18/LL-37 is detected in desquamated epithelial cells of human whole saliva, but the functional importance of this pool of hCAP18/LL-37 is not understood. Here, we assess the impact of homogenates of desquamated oral epithelial cells and exogenous, synthetic LL-37 on two oral bacteria: S. mutans and S. gordonii. Material and methods: Desquamated epithelial cells of unstimulated whole saliva were isolated and cellular and extracellular levels of hCAP18/LL-37 analyzed by ELISA. Bacterial viability was determined by BacLight Live/Dead staining and confocal laser scanning microscopy. Results: Desquamated oral epithelial cells harboured hCAP18/LL-37, and they spontaneously released/leaked the peptide to their medium. Exogenous, synthetic LL-37 showed cytotoxic activity against S. mutans but not S gordonii, suggesting that LL-37 acts differentially on these two types of oral bacteria. Homogenates of desquamated oral epithelial cells had no effect on S. mutans viability. Treatment with exogenous, synthetic LL-37 (8 and 10 μM) reduced S. mutans viability, whereas lower concentrations (0.1 and 1 µM) of the peptide lacked effect. Conclusions: Desquamated oral epithelial cells contain hCAP18/LL-37, but their cellular levels of hCAP18/LL-37 are too low to affect S. mutans viability, whereas exogenous, synthetic LL-37 has a strong effect on these bacteria.
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| 4. |
- Aidoukovitch, Alexandra, et al.
(författare)
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Strontium chloride promotes cell proliferation in a human osteoblast cell line
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Strontium ranelate (SrRan) is the active component of drugs currently used for reducing the risk of fractures in patients suffering from osteoporosis. Despite extensive use, the underlying mechanisms of action of Sr2+ are not fully understood. In the present study, we assess the impact of SrCl2 on human osteoblast activity and proliferation. Cultures of the human osteoblast-like cell line MG63 were treated for 72 h in presence of 0.1 mM, 1 mM, 5 mM and 10 mM SrCl2 or vehicle, used in control groups. Cells were counted manually using a Bürker chamber. Total protein content was determined by colorimetric analysis performed by a microplate reader using Bio-Rad protein assay. Alkaline phosphatase (ALP) activity was determined enzymatically and normalized to total protein content in each sample. Cell viability was assessed using the MTT assay. Treatment with 5 mM SrCl2 for 72 h enhanced total MG63 cell protein content by 37% compared to controls (p<0.01). A lower concentration (0.1 mM) of SrCl2 had no effect on total protein. Incubation with 5 mM SrCl2 for 72 h increased MG63 cell number by 38% compared to controls (p<0.001). The SrCl2-induced increase in cell number was associated with enhanced (+14% compared to controls, p<0.05) cell viability. Treatment with a higher concentration (10 mM) of SrCl2 enhanced cell number similar to 5 mM SrCl2 (+54% compared to controls, p<0.05). Treatment with 0.1 or 5 mM SrCl2 for 72 h had no effect (p>0.05) on MG63 cell ALP activity, while 1 mM SrCl2 reduced ALP activity as well as total protein content by about 25% compared to controls (p<0.05). The current results demonstrate that treatment with SrCl2 for 72 h, at concentrations higher than 1 mM promotes cell proliferation in human osteoblast-like cells, suggesting that Sr2+ may enhance bone formation through this mechanism.
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| 5. |
- Aidoukovitch, Alexandra, et al.
(författare)
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The host defense peptide LL-37 is internalized by human periodontal ligament cells and prevents LPS-induced MCP-1 production
- 2019
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Ingår i: Journal of Periodontal Research. - : Wiley. - 0022-3484 .- 1600-0765. ; 54:6, s. 662-670
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The human host defense peptide LL-37 both shows antimicrobial effects and modulates host cell properties. Here, we assess the effects of synthesized LL-37 on lipopolysaccharide (LPS)-induced inflammation in human periodontal ligament (PDL) cells and investigates underlying mechanisms. Background: LL-37 has been detected in the periodontal tissues, but its functional importance for PDL cell innate immune responses is not known. Methods: Human PDL cells were obtained from premolars extracted on orthodontic indications. Cellular pro-inflammatory monocyte chemoattractant protein-1 (MCP-1) mRNA expression was determined using quantitative real-time RT-PCR. MCP-1 protein production was assessed by western blot and ELISA. Internalization of LL-37 by PDL cells was visualized by immunocytochemistry. Nuclear factor kappa-light-chain-enhancer of activated B-cell (NF-κB) activity was assessed by western blot of phosphorylated p65, phosphorylated p105, and IκBα proteins. Binding of LL-37 to PDL cell DNA was determined by isolation and purification of DNA and dot blot for LL-37 immunoreactivity. Results: Treatment with LL-37 (1 µmol/L) for 24 hours prevented LPS-induced stimulation of MCP-1 expression analyzed both on transcript and on protein levels. Stimulation with LL-37 (1 µmol/L) for 24 hours had no effect on toll-like receptor (TLR)2 and TLR4 transcript expression, suggesting that LL-37 acts downstream of the TLRs. Preincubation with LL-37 for 60 minutes followed by stimulation with LPS for 24 hours in the absence of LL-37 completely prevented LPS-evoked MCP-1 transcript expression, implying that LL-37 acts intracellularly and not via binding and neutralization of LPS. In PDL cells stimulated with LL-37 for 60 minutes, the peptide was internalized as demonstrated by immunocytochemistry, suggesting an intracellular mechanism of action. LL-37 immunoreactivity was observed both in the cytosol and in the nucleus. Downregulation of LPS-induced MCP-1 by LL-37 was not mediated by reduction in NF-κB activity as shown by unaltered expression of phosphorylated p65, phosphorylated p105, and IκBα NF-κB proteins in the presence of LL-37. Immunoreactivity for LL-37 was observed in PDL cell DNA treated with but not without 0.1 and 1 µmol/L LL-37 for 60 minutes in vitro. Conclusion: LL-37 abolishes LPS-induced MCP-1 production in human PDL cells through an intracellular, NF-κB-independent mechanism which probably involves direct interaction between LL-37 and DNA.
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| 6. |
- Aidoukovitch, Alexandra, et al.
(författare)
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Vitamin D triggers hCAP18/LL-37 production : Implications for LL-37-induced human osteoblast cytotoxicity
- 2024
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Ingår i: Biochemical and Biophysical Research Communications. - 0006-291X. ; 712-713
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Tidskriftsartikel (refereegranskat)abstract
- The human cathelicidin LL-37 shows activity against microorganisms, but it is also cytotoxic to host cells. The CAMP gene codes for the LL-37 precursor hCAP18 which is processed extracellularly to active LL-37. It has previously been shown that vitamin D stimulates CAMP gene activity, but less information is available demonstrating that vitamin D also can increase hCAP18/LL-37 protein production. Here, we show with RT-qPCR that a physiological concentration of vitamin D (50 nM) enhances CAMP mRNA levels by about 170 times in human THP-1 monocyte cells. Stimulation with 50 nM vitamin D increases hCAP18/LL-37 protein contents 3–4 times in THP-1 cell lysates demonstrated by both dot blot analysis and ELISA applying two different hCAP18/LL-37 antibodies. Treatment with the proteasome inhibitor MG132 enhances hCAP18/LL-37 levels, suggesting that turnover of hCAP18/LL-37 protein is regulated by the proteasome. The hCAP18/LL-37 concentration in vitamin D-stimulated THP-1 cells corresponds to 1.04 μM LL-37. Interestingly, synthetic LL-37, at this concentration, reduces viability of human osteoblast-like MG63 cells, whereas the THP-1 cells are less sensitive as demonstrated by the MTT assay. In summary, we show that vitamin D enhances hCAP18/LL-37 production, and that this effect can be of physiological/pathophysiological relevance for LL-37-induced human osteoblast toxicity.
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| 7. |
- Odlén, Karin, et al.
(författare)
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Odontoblast-like MDPC-23 cells produce pro-inflammatory IL-6 in response to lipoteichoic acid and express the antimicrobial peptide CRAMP.
- 2020
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Ingår i: Acta Odontologica Scandinavica. - : Taylor & Francis. - 0001-6357 .- 1502-3850. ; 78:3, s. 210-216
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Tidskriftsartikel (refereegranskat)abstract
- Odontoblasts are thought to be involved in innate immunity but their precise role in this process is not fully understood. Here, we assess effects of lipopolysaccharide (LPS) and lipoteichoic acid (LTA), produced by Gram-negative and Gram-positive bacteria, respectively, on matrix metalloproteinase-8 (MMP-8), interleukin-6 (IL-6) and cathelin-related antimicrobial peptide (CRAMP) expression in odontoblast-like MDPC-23 cells. Gene activity and protein production was determined by quantitative real-time RT-PCR and ELISA, respectively. Cellular expression of CRAMP was determined by immunocytochemistry. Stimulation with LTA (5 and 25 µg/ml) but not LPS (1 and 5 µg/ml) for 24 h enhanced IL-6 mRNA expression. The LTA-induced up-regulation of IL-6 mRNA levels was associated with increased IL-6 protein levels. Stimulation with either LPS or LTA for 24 h lacked effect on both MMP-8 transcript and protein expression. Immunocytochemistry disclosed that MDPC-23 cells expressed immunoreactivity for CRAMP. MDPC-23 cells showed mRNA expression for CRAMP, but stimulation with either LPS or LTA did not modulate CRAMP transcript expression. We show that MDPC-23 cells possess immune-like cell properties such as LTA-induced IL-6 production and expression of the antimicrobial peptide CRAMP, suggesting that odontoblasts may modulate innate immunity via these mechanisms.
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| 8. |
- Svensson, Daniel, et al.
(författare)
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Secretory leukocyte protease inhibitor regulates human periodontal ligament cell production of pro-inflammatory cytokines
- 2017
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Ingår i: Inflammation Research. - : Springer Science and Business Media LLC. - 1023-3830 .- 1420-908X. ; 66:9, s. 823-831
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Regulation of immune-like cell properties of periodontal ligament (PDL) cells is not understood. We investigate the importance of secretory leukocyte protease inhibitor (SLPI) for production of pro-inflammatory cytokines in human PDL cells. Materials and methods: PDL cells were isolated from teeth extracted for orthodontic reasons. Cellular location of SLPI was investigated by immunocytochemistry. Cytokine transcript and protein expression were assessed by quantitative real-time RT-PCR and Western blotting. SLPI gene activity was knocked-down by siRNA. NF-κB signaling was assessed by measuring IκBα, and phosphorylated p65 and p105 protein expression. Results: PDL cells showed cytoplasmic expression of SLPI. Cellular expression level of SLPI negatively correlated to LPS-induced stimulation of IL-6 and MCP-1. Both SLPI gene activity and protein were reduced by about 70% in PDL cells treated with SLPI siRNA compared to cells treated with non-coding construct. Treatment with SLPI siRNA was associated with up-regulation of both basal and LPS-stimulated IL-6, MCP-1 and TLRs mRNA expression. The up-regulation of MCP-1 transcript in SLPI siRNA-treated cells was confirmed on protein level. SLPI siRNA-treatment enhanced the phosphorylated NF-κB p105 protein expression. Conclusions: SLPI regulates PDL cell pro-inflammatory cytokine expression and modulates NF-κB signaling, suggesting that SLPI governs the immune cell-like properties of PDL cells.
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| 9. |
- Svensson, Daniel, et al.
(författare)
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The host defense peptide LL-37 is detected in human parotid and submandibular/sublingual saliva and expressed in glandular neutrophils
- 2018
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Ingår i: European Journal of Oral Sciences. - : Blackwell Munksgaard. - 0909-8836 .- 1600-0722. ; 126:2, s. 93-100
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Tidskriftsartikel (refereegranskat)abstract
- The human host defense peptide, LL-37, is an important player in the first line of defense against invading microorganisms. LL-37 and its precursor, hCAP18, have been detected in unstimulated whole saliva but no reports showing hCAP18/LL-37 in isolated, parotid, and/or submandibular/sublingual saliva have been presented. Here, we measured the levels of hCAP18/LL-37 in human parotid and submandibular/sublingual saliva and investigated the expression of hCAP18/LL-37 in parotid and submandibular gland tissue. Parotid and submandibular/sublingual saliva was collected from healthy volunteers, and the levels of hCAP18/LL-37 in saliva were analyzed by dot blot, ELISA, and western blotting. Cellular expression of hCAP18/LL-37 in human parotid and submandibular glands was investigated by immunohistochemistry. Immunoreactivity for hCAP18/LL-37 was detected in both parotid and submandibular/sublingual saliva of all individuals. The concentration of hCAP18/LL-37 was similar in parotid and submandibular/sublingual saliva, and was determined by densitometric scanning of each dot and normalization to the total protein concentration of each sample, and by ELISA. Double immunohistochemistry revealed that intravascular neutrophils of both parotid and submandibular glands express hCAP18/LL-37. For the first time, we demonstrate hCAP18/LL-37 in isolated human parotid and submandibular/sublingual saliva and expression of hCAP18/LL-37 in glandular intravascular neutrophils, indicating that neutrophils of the major salivary glands contribute to the LL-37 content of whole saliva.
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