在空气—液体交界面培养角朊细胞

为使体外培养的角朊细胞在近似体内状况下生长,本实验将人体表皮角朊细胞置于塑料培养环内的胶原基质上进行空气—液体交界面培养。培养14d后,将培养物冰冻切片,行普通细胞染色和免疫细胞化学检查,结果显示,有多层细胞形成,且在上层细胞中出现filaggrin。提示此培养技术可用于研究人体表皮细胞的生长和分化。     

The human antimicrobial peptide dermcidin activates normal human keratinocytes

Background  The skin has evolved an epithelial defence mechanism which is characterized by antimicrobial peptides that inactivate various microorganisms and exhibit stimulatory activities bridging innate and adaptive immunity. Dermcidin (DCD) is a newly isolated antimicrobial peptide produced by the eccrine sweat glands in the skin. Recently, the DCD peptides DCD-1 and DCD-1L have been shown to display in vitro microbicidal activities against bacteria and viruses.
Objectives  Because some skin-derived antimicrobial peptides activate keratinocytes, we investigated whether DCD-1L would also trigger keratinocyte activation.
Methods  Normal human keratinocytes were used in this study. The ability of DCD-1L to induce the production of cytokines/chemokines by keratinocytes was determined by enzyme-linked immunosorbent assay, and various inhibitors were used to investigate the stimulatory mechanism of DCD-1L. Mitogen-activated protein kinase (MAPK) phosphorylation and NF-κB activation were analysed by Western blotting.
Results  DCD-1L stimulated keratinocytes to generate cytokines and chemokines including tumour necrosis factor-α, interleukin-8 (CXCL8), interferon-inducible protein 10 (CXCL10) and macrophage inflammatory protein-3α (CCL20). To determine the molecular mechanism involved, we showed that DCD-1L-mediated cytokine/chemokine production was controlled by both G-protein and MAPK pathways, as evidenced by the inhibitory effects of pertussis toxin and specific inhibitors for p38 and ERK, but not for JNK, on DCD-1L-induced keratinocyte activation. Furthermore, we confirmed that DCD-1L could induce phosphorylation of p38 and ERK, and noticeably upregulated NF-κB activation.
Conclusions  Taken together, the new activity of DCD-1L to stimulate the production of cytokines/chemokines by keratinocytes provides novel evidence for the implication of DCD, beyond its microbicidal ability, in skin immunity.     

1 alpha,24R-dihydroxyvitamin D3 has an ability comparable to that of 1 alpha,25-dihydroxyvitamin D3 to induce keratinocyte differentiation

Using cultured normal human keratinocytes, we compared the activities of 1 alpha,24-dihydroxyvitamin D3 (1,25(OH)2D3), a biologically active form, in inducing cell differentiation. Treatment with 10(-6) M of 1,24R(OH)2D3 and 1,25(OH)2D3 increased the number of involucrin positive cells (differentiated from 6.4% to 24.1% and 25.1%, respectively. These results indicate that 1,24R(OH)2D3 has an ability comparable to that of 1,25(OH)2D3 to induce cell differentiation in human keratinocytes. The clinical effectiveness of 1,24R(OH)2D3 for the treatment of psoriasis may be, in part, related to its direct effect on hyperproliferative keratinocytes.     

Lanthanum-induced alterations in the distribution of actin filaments in human keratinocytes

The effects of La³⁺ on the distribution and organization of actin in human keratinocytes were examined with rhodamine-phalloidin staining. At 0.2 and 0.02 mM concentrations, La³⁺ induced redistribution and organization of actin. Thick bundles of actin filaments appeared, as did fine ripple-like short bundles and polygonal structures. Thick, ribbon-like assemblages of actin were crescent-shaped or semi-circular. These changes were quite similar to those induced by TPA. The effects of La³⁺ were discussed with reference to Ca²⁺.     

Keratinocytes efficiently process endogenous antigens for cytotoxic T‐cell mediated lysis

Abstract: The generation of a robust CD8⁺ cytotoxic T lymphocyte (CTL) response is a key feature of many immunotherapeutic strategies against epithelial tumors and virally infected epithelial tissue. However, surprisingly few studies have addressed whether primary epithelial cells, expressing defined endogenous antigens, are good targets for CTL‐mediated lysis. Here, we show that primary keratinocytes (KCs), expressing endogenous ovalbumin (OVA) as a transgene, present measurable H‐2K^b/SIINFEKL complexes at the cell surface and are killed by OVA‐specific CTL. Target cell lysis was comparable with a more traditional CTL target cell, EL4, and was enhanced by KC pretreatment with interferon‐γ. These results suggest that primary KCs will be susceptible to CTL‐mediated apoptosis when endogenous KC antigens are targeted during immunotherapy.     

Monoclonal Antibody OKB19, Reactive with a B-Lymphoid Differentiation Antigen (CD19), Binding to Basal Layer Keratinocytes of Normal Human Skin

Monoclonal antibody (moAB) OKB19 reacts with CD19 antigen, which is the broadest lineage-specific surface marker on B-lymphocytes. In frozen tissue sections, using an immunohistochemical technique, the OKB19-positive cells in the basal layer were sharply demarcated from the negative suprabasal layers. In normal hair follicles, the OKB19 reactivity was also confined to one layer of the dermal side of the outer root sheath. However, this reactivity gradually disappeared in the lower areas. The inner surface of the lumina in the eccrine duct was weakly stained with OKB19. The basal keratinocytes were also stained with OKB19 in the lesional epidermis of the various dermatoses examined in this study, when the basal keratinocytes remained unaffected. Even in the hyperproliferative state of psoriasis, the OKB19 reactivity was confined to the basal layer. Several kinds of tumor cells derived from the skin were not stained with OKB19. No labeling was seen even in the basaloid cells of basal cell carcinoma, which are morphologically similar to basal keratinocytes. B4 and Leu-12, other monoclonal antibodies reacting with CD19, did not recognize any keratinocytes in the normal human skin. MoAB OKB19, therefore, reacts with an antigen present on basal keratinocytes and provides a probe for the isolation of the basal keratinocyte subpopulation. Thus, this antibody should be useful in studies of not only B-lymphocyte differentiation, but also normal and aberrant differentiation of the epidermal keratinocytes.     

ERK 信号通路介导银屑病角质形成细胞过度增殖的调控机制

银屑病是常见的慢性、 复发性、 炎症性皮肤病, 角质形成细胞 ( keratinocyte, KC) 增殖分化失 调作为其发病原因之一, 具体机制尚未明确。 细胞外信号调节激酶 ( extracellular signal regulated kinase, ERK) 信号通路在其中发挥着重要作用, 微小 RNA (microRNA, miRNA)、 长链非编码 RNA ( lncRNA)、 细胞因子等作为 ERK 信号通路的上游分子参与调控银屑病表皮角质形成细胞的增殖与分化过程。 文章旨在 对这一通路在银屑病角质形成细胞过度增殖中的作用机制做一综述。     

不同物理和化学因素对重组人角质细胞生长因子2稳定性的影响

目的:研究重组人角质细胞生长因子2 (rhKGF-2)在不同保存条件下的稳定性,阐明温度、pH值、缓冲溶液及反复冻融因素对rhKGF-2稳定性的影响作用。方法: rhKGF-2在不同温度(－20℃、4℃、25℃、40℃)、pH值(pH 4～9)、缓冲溶液（柠檬酸钠-柠檬酸缓冲液、磷酸氢二钠-柠檬酸缓冲液、磷酸盐缓冲液、吉斐氏缓冲溶液）及反复冻融条件下分别保存,采用RP-HPLC法检测rhKGF-2纯度,同时观察外观性状。结果：－20℃、4℃分别保存时,rhKGF-2的各项性质在观察期内都无明显变化;25℃时,rhKGF-2存放28 d纯度较0 h(100.00%)下降至(68.20±0.14)%;40℃时,rhKGF-2存放9 h纯度较0 h(100.00%)下降至(4.80±0.39)%。rhKGF-2(pH　6.0)在25℃条件下保存90 d纯度较0 h(100.00%)下降至(79.20±0.12)%,与对照组(0 h)比较差异有显著性(P<0.05);pH值为4.0、9.0的rhKGF-2液体在25℃条件下分别保存120　h纯度较0 h(100.00%)下降至(15.60±0.30)%和(67.30±0.10)%,与对照组(0 h)比较差异有显著性(P<0.01)。rhKGF-2在柠檬酸缓冲液中25℃条件下保存60　d纯度较0 h(100.00%)下降至(79.20±0.15)%,与对照组(0 h)比较差异有显著性(P<0.01)。rhKGF-2原液反复冻融后其纯度变化差异无显著性(P>0.05)。结论：rhKGF-2在低温和pH 6.0～7.0中性条件下稳定。高温、偏酸性和偏碱性条件下均不利于rhKGF-2稳定。柠檬酸缓冲液有利于rhKGF-2稳定。反复冻融对rhKGF-2稳定性影响不明显。