Small interfering RNA targeting of keratin 17 reduces inflammation in imiquimod-induced psoriasis-like dermatitis.

BACKGROUND: Psoriasis is a common chronic inflammatory skin disease with 2% to 3% prevalence worldwide and a heavy social-psychological burden for patients and their families. As the exact pathogenesis of psoriasis is still unknown, the current treatment is far from satisfactory. Thus, there is an urgent need to find a more effective therapy for this disease. Keratin 17 (K17), a type I intermediate filament, is overexpressed in the psoriatic epidermis and plays a critical pathogenic role by stimulating T cells in psoriasis. Therefore, we hypothesized that inhibiting K17 may be a potential therapeutic approach for psoriasis. This study aimed to investigate the therapeutic effect of K17-specific small interfering RNA (siRNA) on mice with imiquimod (IMQ)-induced psoriasis-like dermatitis. METHODS: Eight-week-old female BALB/c mice were administered a 5% IMQ cream on both ears to produce psoriatic dermatitis. On day 3, K17 siRNA was mixed with an emulsion matrix and applied topically to the left ears of the mice after IMQ application every day for 7 days. The right ears of the mice were treated in parallel with negative control (NC) siRNA. Inflammation was evaluated by gross ear thickness, histopathology, the infiltration of inflammatory cells (CD3+ T cells and neutrophils) using immunofluorescence, and the expression of cytokine production using real-time quantitative polymerase chain reaction. The obtained data were statistically evaluated by unpaired t-tests and a one-way analysis of variance. RESULTS: The severity of IMQ-induced dermatitis on K17 siRNA-treated mice ears was significantly lower than that on NC siRNA-treated mice ears, as evidenced by the alleviated ear inflammation phenotype, including decreased ear thickness, infiltration of inflammatory cells (CD3+ T cells and neutrophils), and inflammatory cytokine/chemokine expression levels (interleukin 17 [IL-17], IL-22, IL-23, C-X-C motif chemokine ligand 1, and C-C motif chemokine ligand 20) (P < 0.05 vs. the Blank or NC siRNA groups). Compared to the NC siRNA treatment, the K17 siRNA treatment resulted in increased K1 and K10 expression, which are characteristic of keratinocyte differentiation (vs. NC siRNA, K17 siRNA1 group: K1, t = 4.782, P = 0.0050; K10, t = 3.365, P = 0.0120; K17 siRNA2 group: K1, t = 4.104, P = 0.0093; K10, t = 4.168, P = 0.0042; siRNA Mix group: K1, t = 3.065, P = 0.0221; K10, t = 10.83, P < 0.0001), and decreased K16 expression, which is characteristic of keratinocyte proliferation (vs. NC siRNA, K17 siRNA1 group: t = 4.156, P = 0.0043; K17 siRNA2 group: t = 2.834, P = 0.0253; siRNA Mix group: t = 2.734, P = 0.0250). CONCLUSIONS: Inhibition of K17 expression by its specific siRNA significantly alleviated inflammation in mice with IMQ-induced psoriasis-like dermatitis. Thus, gene therapy targeting K17 may be a potential treatment approach for psoriasis.

Decreased expression levels of complement regulator CD55 contribute to the development of bullous pemphigoid.

Bullous pemphigoid is a common autoimmune blistering disease of the elderly associated with autoantibody-mediated complement activation, and complement dysregulation is critical for its pathogenesis. As a crucial regulator of the complement system, CD55 has been widely studied in autoimmune diseases. Here, we investigated the involvement of CD55 in bullous pemphigoid, as little is known regarding its role in this disease. We found that CD55 levels were significantly lower in the lesions of patients with bullous pemphigoid (n = 8) compared to those in skin samples from healthy controls (n = 6). Interestingly, CD55 depletion in HaCaT human keratinocytes enhanced autoantibody-mediated complement activation. Moreover, complement activation was blocked by exogenous recombinant CD55 protein in both skin sections and keratinocytes exposed to pathogenic antibodies from patients with bullous pemphigoid. Notably, a significant increase in the expression of TNF-α and IFN-γ, administration of which downregulated CD55 levels in HaCaT cells, was observed in the sera of patients with bullous pemphigoid (n = 38) compared to that in healthy controls (n = 19). We found that ERK1/2 is involved in both TNF-α- and IFN-γ-induced CD55 downregulation. Thus, CD55 deficiency is a crucial factor in bullous pemphigoid pathogenesis, suggesting that increasing CD55 levels may exert a therapeutic effect.

Measurement of facial bone wall thickness of maxillary anterior teeth and premolars on cone beam computed tomography images / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To measure the thickness of facial bone wall of maxillary anterior teeth and premolars based on cone beam computed tomography (CBCT) images.</p><p><b>METHODS</b>CBCT images from 118 patients were collected from the Affiliated Stomatology Hospital of Zhejiang University. The thickness perpendicular to the long axis of facial bone wall was measured at two locations: 4 mm apical to the cementoenamel junction (point 1) and the middle of the root (point 2).</p><p><b>RESULTS</b>The thickness of the facial bone walls of central incisors, lateral incisors and canines ranged from 0.5 to 1.5 mm. A thin facial bone wall (<1.0 mm) was quite frequent in central incisors (44.1% at point 1, 56.8% at point 2), lateral incisors (65.2% at point 1, 89.8% at point 2) and canines (45.8% at point 1, 61.0% at point 2). In contrast, the majority of examined first premolars (77.1% at point 1, 68.7% at point 2) and second premolars (94.1% at point 1, 94.1% at point 2) exhibited a thick facial bone wall (>1.0 mm).</p><p><b>CONCLUSION</b>A thin facial bone wall of teeth in the anterior maxilla is common. Radiographic analysis of facial bone wall using CBCT is recommended for selection of appropriate treatment approach.</p>

Human IgG1 monoclonal antibody against human collagen 17 noncollagenous 16A domain induces blisters via complement activation in experimental bullous pemphigoid model.

Bullous pemphigoid (BP) is an autoimmune blistering disease caused by IgG autoantibodies targeting the noncollagenous 16A (NC16A) domain of human collagen 17 (hCOL17), which triggers blister formation via complement activation. Previous in vitro analysis demonstrated that IgG1 autoantibodies showed much stronger pathogenic activity than IgG4 autoantibodies; however, the exact pathogenic role of IgG1 autoantibodies has not been fully demonstrated in vivo. We constructed a recombinant IgG1 mAb against hCOL17 NC16A from BP patients. In COL17-humanized mice, this mAb effectively reproduced a BP phenotype that included subepidermal blisters, deposition of IgG1, C1q and C3, neutrophil infiltration, and mast cell degranulation. Subsequently, alanine substitutions at various C1q binding sites were separately introduced to the Fc region of the IgG1 mAb. Among these mutated mAbs, the one that was mutated at the P331 residue completely failed to activate the complement in vitro and drastically lost pathogenic activity in COL17-humanized mice. These findings indicate that P331 is a key residue required for complement activation and that IgG1-dependent complement activation is essential for blister formation in BP. This study is, to our knowledge, the first direct evidence that IgG1 Abs to hCOL17 NC16A can induce blister formation in vivo, and it raises the possibility that IgG1 mAbs with Fc modification may be used to block pathogenic epitopes in autoimmune diseases.