Continuous application of compressive force induces fusion of osteoclast-like RAW264.7 cells via upregulation of RANK and downregulation of LGR4.

AIMS: During orthodontic treatment, facilitating osteoclastic bone resorption in the alveolar bone exposed to the compressive force (CF) is an important factor for tooth movement. The present study investigated the effect of CF stimulation on the differentiation of RAW264.7 cells from precursors to mature osteoclasts. MAIN METHODS: The cells were continuously stimulated with 0.3, 0.6, or 1.1 g/cm2 CF-which was generated by increasing the volume of culture medium in the wells of a 96-well plate-in the presence or absence of receptor activator of nuclear factor κB (RANK) ligand (RANKL) for 4 days. KEY FINDINGS: In the presence of RANKL, the number of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells and the mRNA levels of dendritic cell-specific transmembrane protein (DC-STAMP) and osteoclast-stimulatory transmembrane protein (OC-STAMP) were increased by application of 0.6 and 1.1 g/cm2 CF as compared to 0.3 g/cm2 CF. The mRNA level of RANK was upregulated whereas that of leucine-rich repeat-containing G-protein-coupled receptor (LGR)4-another RANKL receptor was downregulated by 0.6 and 1.1 g/cm2 CF as compared to 0.3 g/cm2 CF in the absence of RANKL. The proportion of cells with nuclear translocation of the nuclear translocation of nuclear factor of activated T cells (NFAT)c1 was increased by 0.6 and 1.1 g/cm2 CF in the presence of RANKL. SIGNIFICANCE: Continuous application of CF induced the differentiation of RAW264.7 cells into TRAP-positive multinuclear cells by enhancing the expression of DC- and OC-STAMP and the nuclear translocation of NFATc1. This may result from the CF-induced increase in RANK and decrease in LGR4 expression.

Effects of C-reactive protein on the expression of matrix metalloproteinases and their inhibitors via Fcγ receptors on 3T3-L1 adipocytes.

The association between obesity and inflammation is well documented in epidemiological studies. Proteolysis of extracellular matrix (ECM) proteins is involved in adipose tissue enlargement, and matrix metalloproteinases (MMPs) collectively cleave all ECM proteins. Here, we examined the effects of C-reactive protein (CRP), an inflammatory biomarker, on the expression of MMPs and tissue inhibitors of metalloproteinases (TIMPs), which are natural inhibitors of MMPs, in adipocyte-differentiated 3T3-L1 cells. We analyzed the expression of Fcγ receptor (FcγR) IIb and FcγRIII, which are candidates for CRP receptors, and the effects of anti-CD16/CD32 antibodies, which can act as FcγRII and FcγRIII blockers on CRP-induced alteration of MMP and TIMP expression. Moreover, we examined the effects of CRP on the activation of mitogen-activated protein kinase (MAPK) signaling, which is involved in MMP and TIMP expression, in the presence or absence of anti-CD16/CD32 antibodies. Stimulation with CRP increased MMP-1, MMP-3, MMP-9, MMP-11, MMP-14, and TIMP-1 expression but did not affect MMP-2, TIMP-2, and TIMP-4 expression; TIMP-3 expression was not detected. Adipocyte-differentiated 3T3-L1cells expressed FcγRIIb and FcγRIII; this expression was upregulated on stimulation with CRP. Anti-CD16/CD32 antibodies inhibited CRP-induced expression of MMPs, except MMP-11, and TIMP-1. CRP induced the phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 and p38 MAPK but did not affect SAPK/JNK phosphorylation, and Anti-CD16/CD32 attenuated the CRP-induced phosphorylation of p38 MAPK, but not that of ERK1/2. These results suggest that CRP facilitates ECM turnover in adipose tissue by increasing the production of multiple MMPs and TIMP-1 in adipocytes. Moreover, FcγRIIb and FcγRIII are involved in the CRP-induced expression of MMPs and TIMP-1 and the CRP-induced phosphorylation of p38, whereas the FcγR-independent pathway may regulate the CRP-induced MMP-11 expression and the CRP-induced ERK1/2 phosphorylation.

Effective treatment for infantile hemangioma with long-pulsed dye laser with oral propranolol medication: a preliminary report.

PURPOSE: To investigate the efficacy of our treatment of infantile hemangioma (IH)s retrospectively presenting as disfiguring or functionally threatening lesions. MATERIALS AND METHODS: 25 infants with IH treated with long-pulsed dye laser or laser with or without propranolol. Tumor fading after treatment was evaluated using both color and size rating scales, before, during and after treatment. RESULTS: 6 infants were treated by laser, 11, oral propranolol and 8 using both treatments. Each treatment was effective for most IH with a median treatment duration of 7.7 months for laser, and 13.3 months for the latter two. Combination therapy was the most effective in both color-fading and size reduction by the 3rd month. Laser alone was most effective in color-fading with almost complete disappearance of most tumors. Oral propranolol to the three site-specific IHs was effective with disappearance of tumors. There were no apparent side effects related to laser treatment, but one infant suffered from allergy and another from bronchial asthma due to propranolol medication. CONCLUSIONS: Most IHs discolored and regressed considerably with these treatments, including complete disappearance of the three functionally threatening lesions. This combined approach is quite useful for accelerating tumor regression.

Effects of ultraviolet light on melanocyte differentiation: studies with mouse neural crest cells and neural crest-derived cell lines.

To evaluate the etiologic role of ultraviolet (UV) radiation in acquired dermal melanocytosis (ADM), we investigated the effects of UVA and UVB irradiation on the development and differentiation of melanocytes in primary cultures of mouse neural crest cells (NCC) by counting the numbers of cells positive for KIT (the receptor for stem cell factor) and for the L-3,4-dihydroxyphenylalanine (DOPA) oxidase reaction. No significant differences were found in the number of KIT- or DOPA-positive cells between the UV-irradiated cultures and the non-irradiated cultures. We then examined the effects of UV light on KIT-positive cell lines derived from mouse NCC cultures. Irradiation with UVA but not with UVB inhibited the tyrosinase activity in a tyrosinase-positive cell line (NCCmelan5). Tyrosinase activity in the cells was markedly enhanced by treatment with alpha-melanocyte-stimulating hormone (alpha-MSH), but that stimulation was inhibited by UVA or by UVB irradiation. Irradiation with UVA or UVB did not induce tyrosinase activity in a tyrosinase-negative cell line (NCCmelb4). Levels of KIT expression in NCCmelan5 cells and in NCCmelb4 cells were significantly decreased after UV irradiation. Phosphorylation levels of extracellular signal-regulated kinase 1/2 in cells stimulated with stem cell factor were also diminished after UV irradiation. These results suggest that UV irradiation does not stimulate but rather suppresses mouse NCC. Thus if UV irradiation is a causative factor for ADM lesions, it would not act directly on dermal melanocytes but may act in indirect manners, for instance, via the overproduction of melanogenic cytokines such as alpha-MSH and/or endothelin-1.

Effective treatment of pruritus in atopic dermatitis using H1 antihistamines (second-generation antihistamines): changes in blood histamine and tryptase levels.

BACKGROUND: Atopic dermatitis (AD) is a common chronic inflammatory and allergic skin disease that almost always begins in childhood and follows a course of remittance and flare-up. AD is characterized by intense pruritus and itchiness that can be triggered by an interplay of genetic, immunologic and environmental factors. Of the mediators, histamine is one of the most potent inducers of pruritus. Serum tryptase, which is also a mediator, may be used to examine allergic disease as well. The development of minimal sedation H1 antihistamines (second-generation antihistamines) has revolutionized treatment of allergic diseases. OBJECTIVE: The present study examines the efficacy of second-generation antihistamines in relieving pruritus due to AD. In addition, the relationship between AD pruritus and antihistamine therapy was analyzed by measuring the blood histamine and tryptase levels. METHODS: Thirty-two AD patients were recruited and underwent second-generation antihistamine therapy for 2 weeks. Seventeen received combined topical corticosteroid treatment (Group 1) and the other 15 did not receive steroid treatment (Group 2). The Severity Index and Pruritus Score were assessed as an AD clinical activity index and compared with baseline data. RESULTS: Both the Severity Index and Pruritus Score improved significantly in Group 1 (P<0.001, P<0.05). Group 2 demonstrated a significant improvement in Pruritus Score (P<0.05), but not in the Severity Index. Plasma histamine levels were significantly higher in AD at baseline compared with healthy controls. CONCLUSION: Following antihistamine therapy, these levels decreased significantly in both AD groups (P<0.05). There was a significant correlation between baseline blood histamine and typtase levels. However, this correlation was not evident following treatment. This may reflect insufficient detection capabilities of the measuring assay. The present results suggest that second-generation antihistamine therapy provides an effective clinical treatment for AD, with a notable improvement in pruritus. Furthermore, antihistamine therapy reduced plasma histamine levels in AD patients. These findings further suggest that high blood histamine and tryptase levels in AD patients contribute to the pathogenesis of this disorder, including the onset of pruritus.