Comparison of broadband UVB, narrowband UVB, broadband UVA and UVA1 on activation of apoptotic pathways in human peripheral blood mononuclear cells

BACKGROUND/PURPOSE: Ultraviolet (UV) radiation is an important therapy for immune-mediated cutaneous diseases. Activation of early apoptotic pathways may play a role in the clinical effectiveness. Different UV wavelengths have different efficacy for various diseases, but it remains unclear whether the ability to induce apoptosis differs with respect to the wavelength, and whether they induce apoptosis through the same mechanism. The aim of this study is to analyze the effects of different UV wavelengths that are used clinically on normal human peripheral blood mononuclear cells (PBMCs). METHODS: PBMCs were treated with UV-light sources broadband UVB, narrowband UVB, broadband UVA and UVA1. Initiation of apoptosis was assessed by flow cytometry by staining-treated cells for activated caspases. Immunoblots were performed to measure for cleaved caspase-3, -8, -9, cytochrome c, Bcl 2-interacting domain and poly-(ADP ribose) polymerase cleavage. RESULTS: We demonstrate that all the UV radiation sources induced caspase activation in a dose-and time-dependent manner. Components of both the extrinsic and intrinsic pathways of apoptosis were activated by all of the UV wavelengths tested, but differed in the level of energy needed for activation. CONCLUSION: The greater effectiveness of UVB on initiation of apoptotic pathway suggests that apoptosis may play a role in the clinical efficacy of UVB-responsive inflammatory cutaneous diseases.     

系统性红斑狼疮患者bcl-2及Fas、Fas配体表达与淋巴细胞凋亡的关系

目的：对SLE患者外周血淋巴细胞凋亡率以及凋亡凋控基因表达蛋白bcl-2、Fas抗原和Fas配体进行分析,以进一步探讨其在SLE发病中的作用及相互关系。方法：应用流式细胞仪检测。结果：SLE患者外周血淋巴细胞凋亡率明显视于正常人（P＜0.01）和其他疾病患者（P＜0.05）;bcl-2抗原表达显著低于正常人和其他疾病患者（P＜0.01）,而Fas抗原、Fas配体表达三组间无明显差异。结论：SLE患者体内淋巴细胞凋亡的明显增加可能与其发病有关,而bcl-2对淋巴细胞凋亡抑制作用的减弱可能较Fas／Fas配体诱导促进淋巴细胞的凋亡更为重要。     

Ultraviolet irradiation induces apoptosis in human immature, but not in skin mast cells

As diverse pruritic cutaneous diseases respond to ultraviolet treatment, we have examined whether ultraviolet light is capable of inducing apoptosis in mast cells. Human mast cell line 1 (HMC1) derived from a patient with malignant mastocytosis and purified skin mast cells were irradiated with single doses of ultraviolet B or ultraviolet A1, or pretreated with 8-methoxypsoralen prior to ultraviolet A1 exposure. After 0 to 48 h of incubation, the percentage of apoptotic and dead cells was assessed. In HMC1 cells, morphologic features of apoptosis were further evaluated by electron microscopy. All ultraviolet treatment induced apoptosis of HMC1 cells in a time- and dose-dependent manner. Apoptosis was associated with activation of caspase-3, release of cytochrome C, cleavage of poly(ADP-ribose)-polymerase, and nuclear accumulation of p53. In contrast, resting skin mast cells were resistant to ultraviolet light induced apoptosis. After incubation with stem cell factor and interleukin-4 for 2 wk, however, slowly proliferating skin mast cells also underwent apoptosis in response to ultraviolet light. In conclusion, these data demonstrate that ultraviolet light directly affects mast cells, but mainly aims at the proliferating mast cells as found in mastocytosis and mast cell dependent pruritic diseases, where increased numbers are observed due to the recruitment mast cell precursors from the blood.     

The FAS/cd95 promoter single-nucleotide polymorphism -670 A/G and lupus erythematosus

An increased level of circulating nuclear antigens caused by apoptosis is thought to be responsible for the production of autoantibodies in lupus erythematosus (LE). The presentation of these antigens to immunologically competent cells may trigger systemic autoimmunity. The influence of a functional single-nucleotide polymorphism at position -670 in the promoter of the apoptosis gene FAS on susceptibility to autoimmune diseases including systemic LE has been a controversial subject. Although it has not yet been possible to assign any particular allele or genotype to the control of FAS expression, this polymorphism has been described to be associated with several autoimmune diseases including LE. When we compared the FAS -670 A/G genotypes of 107 German patients with LE and those of 96 healthy controls, we found a trend for association between LE and the homozygous A genotype in the patient group. This finding suggests that apoptosis may contribute to development of autoimmune reactions and that FAS function might be relevant for LE.     

Apoptosis as a mechanism of keratinocyte death in toxic epidermal necrolysis

Summary Toxic epidermal necrolysis (TEN) and Stevens-Johnson syndrome (SJS) are life-threatening diseases characterized by extensive epidermal destruction. The aim of our study was to investigate apoptosis in keratinocytes of patients with TEN and TEN/SJS overlap syndrome. Keratinocytes from TEN patients were found to undergo extensive apoptosis. These results suggest that cell destruction in TEN occurs as a result of apoptosis. Our findings suggest that apoptosis inhibitory agents may play an important part in the therapeutic strategy of TEN.     

角质形成细胞的凋亡失调及相关皮肤病

角质形成细胞的凋亡在调节表皮发育和抑癌中起着关键作用，凋亡可平衡角质形成细胞的增殖来保持表皮厚度，促使角质层形成和清除恶化前细胞。除正常发展程序外，角质形成细胞的凋亡能被紫外线和其他刺激诱发，凋亡在保持皮肤细胞内环境稳定和一些皮肤病的发病机制中起着重要作用。     

1Alpha,25-dihydroxyvitamin D3 protects human keratinocytes from apoptosis by the formation of sphingosine-1-phosphate.

Owing to its ability to induce growth arrest and differentiation of keratinocytes, 1alpha,25-dihydroxyvitamin D3 and its analogs are useful for the treatment of hyperproliferative skin diseases, such as psoriasis vulgaris. It has been implicated that the 1alpha,25-dihydroxyvitamin D3-induced differentiation of keratinocytes is mediated, at least in part, by the formation of ceramides; however, ceramides have also been identified to induce apoptosis in many cells, including keratinocytes. Therefore, it was of interest to investigate the influence of 1alpha,25-dihydroxyvitamin D3 on apoptosis in keratinocytes. Most interestingly, physiological concentrations of 1alpha,25-dihydroxyvitamin D3 did not induce apoptosis in keratinocytes, despite the formation of ceramides. Moreover, 1alpha,25-dihydroxyvitamin D3 appeared cytoprotective and made keratinocytes resistant to apoptosis induced by ceramides, ultraviolet irradiation, or tumor necrosis factor-alpha. The cytoprotective effect was accompanied by the formation of the sphingolipid breakdown product sphingosine-1-phosphate, which prevented apoptosis in analogy to 1alpha,25-dihydroxyvitamin D3. The effect of 1alpha,25-dihydroxyvitamin D3 was specific as the almost inactive precursor cholecalciferol neither induced sphingosine-1-phosphate formation nor prevented cells from apoptosis. Besides this, the cytoprotective aptitude of 1alpha,25-dihydroxyvitamin D3 was completely abolished by the sphingosine kinase inhibitor N,N-dimethylsphingosine, which blocked sphingosine-1-phosphate formation. Moreover, sphingosine-1-phosphate was able to restore the cytoprotective effect of 1alpha,25-dihydroxyvitamin D3 in the presence of N,N-dimethylsphingosine. Taken together, here we report for the first time that 1alpha,25-dihydroxyvitamin D3 protects keratinocytes from apoptosis and additionally this cytoprotection is mediated via the formation of sphingosine-1-phosphate.     

Deregulation of cell‐death pathways as the cornerstone of skin diseases

Deregulation of cell‐death pathways plays a key role in the pathogenesis of various skin diseases. The different types of cell death are mainly defined by morphological criteria, and include apoptosis, autophagic cell death, and necrosis. The process of apoptosis is well characterized at the molecular level and involves the activation of two main pathways, the intrinsic and extrinsic pathways, converging into the execution of apoptosis by intracellular cysteine proteases, called caspases. The relevance and implication of these apoptotic pathways in the pathophysiology of skin diseases, such as toxic epidermal necrolysis, graft‐versus‐host disease and skin cancer, has been extensively studied. The role of autophagic cell death in progression of skin tumours and response to cytotoxic drugs is only beginning to be elucidated.     

TWEAK/Fn14信号在皮肤病诊断与治疗中的作用

肿瘤坏死因子样细胞弱凋亡因子(TWEAK)属于肿瘤坏死因子配体超家族成员,通过激活其受体成纤维细胞生长诱导因子14(Fn14)而发挥多种生物学功能。TWEAK/Fn14信号的激活可以调控细胞增殖、分化过程,促进纤维增生反应、血管形成和炎症反应,参与红斑狼疮、银屑病、皮肤肿瘤等疾病的发病过程。TWEAK在某些皮肤病患者的血清及尿液中表达上调,有潜力成为早期诊断及活动度评估的生物学标志物。适度激活TWEAK/Fn14信号可促进皮肤创伤愈合,但过强或延长激活该信号则会导致各种病理性组织损害,故激活或阻断该信号的特定环节有望成为治疗皮肤病的新策略。本文综述了TWEAK/Fn14信号在皮肤病发病机制中的作用,探讨该信号在相关诊断与治疗中的潜在价值。     

Numerical, morphological and phenotypic changes in Langerhans cells in the course of murine graft-versus-host disease

BACKGROUND: In the course of graft-versus-host disease (GVHD) or diseases that histologically mimic GVHD (e.g. toxic epidermal necrolysis, Stevens-Johnson syndrome), it is known that epidermal Langerhans cells (LCs) are depleted from the epidermis. However, the mechanism and significance of LC depletion is not well known. OBJECTIVES: To investigate the numerical, morphological and phenotypic changes in LCs and apoptosis of LCs in the course of GVHD using a non-irradiated mouse GVHD model. METHODS: BALB/c nu/nu mice and C57BL/6 mice were used as recipients and donors, respectively. Recipient mice were injected with T-cell-enriched donor spleen cells. Skin samples were harvested at various times after the inoculation. The numerical and morphological changes were examined by an immunofluorescence study of epidermal sheets. Apoptosis was studied by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labelling method and flow cytometric analysis using annexin V. Phenotypic change was studied by flow cytometric analysis of epidermal cell suspensions. The mixed epidermal cell lymphocyte reaction (MELR) was performed to examine functional changes in the epidermal cells. RESULTS: Five days after inoculation, a graft-versus-host reaction occurred. Epidermal LCs began to decrease from the sixth day. On the fifth day, the LCs became larger and had prominent dendrites. Immediately before the LCs began to decrease, many LCs became round in shape, with scanty dendrites. LC apoptosis was not observed in the epidermis either on the fifth or seventh day. Phenotypically, the expression of CD40, CD80, CD86 and major histocompatibility complex class II antigen on the LCs was upregulated on the fifth and seventh day. Epidermal cells from GVHD mice showed an increased allostimulatory capacity in the secondary MELR. CONCLUSIONS: These results suggest that at early GVHD onset, most LCs may not undergo apoptosis in the epidermis but are phenotypically activated, resulting in further activation of alloreactive T cells and aggravation of the disease.     

高压氧治疗皮肤病的研究进展

高压氧治疗是机体在高于一个标准大气压（ATA）的条件下吸入等压的纯氧而达到疗效的一种方法,目前已用于多种皮肤病的辅助治疗。可以肯定的是高压氧可增加皮肤组织内氧含量,加强皮肤的有氧代谢,促进上皮再生和皮损愈合;减轻皮肤末梢神经和感受器的不良刺激;抑制神经元的凋亡;增强调节性T细胞的功能,减轻炎症反应;动员血管干/祖细胞从骨髓迁移至外周血和溃疡组织中。高压氧广泛用于辅助治疗银屑病、特应性皮炎、带状疱疹后遗神经痛、慢性难治性皮肤溃疡、坏疽性脓皮病、真菌感染、面部填充术血管栓塞并发症以及其他皮肤病。     

Patterns of cell death: the significance of apoptosis for dermatology

Abstract Development, function, remodelling, and senescence of multicellular organisms depend on the coordinated occurrence of physiological, actively induced cell death in two major patterns: terminal differentiation and programmed cell death (apoptosis). Apoptosis is a highly selective form of “cell suicide” with characteristic morphological and biochemical features: chromatin condensation, formation of apoptotic bodies, and DNA fragmentation by activation of endonucleases. Here, we outline the current understanding of apoptosis and its subtypes, discuss their biological functions, and delineate why apoptosis is relevant to the skin and its diseases. We distinguish apoptosis from necrosis, and discuss the regulation of apoptosis by selected genes, hormones, growth factors and cytokines. The epidermis and the regressing hair follicle offer interesting models for studying the as yet ill-understood biology of epithelial cell apoptosis. The selective manipulation of cell death programs may become part of the therapeutic arsenal of clinical dermatology.     

Antitumour effects in mycosis fungoides of the immunomodulatory, tellurium-based compound, AS101

BACKGROUND: The immunomodulator AS101 [ammonium trichloro (dioxoethylene-O,O') tellurate], a nontoxic tellurium (IV) compound, has antitumoral effects which were demonstrated in several preclinical and clinical studies. OBJECTIVES: To investigate the antitumour activity of AS101 on cutaneous T-cell lymphoma (CTCL), of which mycosis fungoides (MF) is the most frequent disease variant. METHODS: We used a newly established mouse xenograft model for MF to test the effect of AS101 in vivo and analysed apoptosis induction in vitro. RESULTS: When injected intratumorally, AS101 delayed tumour growth in a dose-dependent manner. In vitro, AS101 induced a dose-dependent G2/M arrest in the CTCL cell lines Hut78 and MyLa. Moreover, higher concentrations of AS101 induced apoptosis in MyLa cells. Programmed cell death was associated with the loss of mitochondrial transmembrane potential and activation of caspase 9 and caspase 3. AS101 also elevated intracellular reactive oxygen species (ROS) production; the antioxidant, Mn superoxide dismutase, significantly reduced the degree of apoptosis, suggesting that ROS play a key role in apoptosis induction. CONCLUSIONS: These findings indicate that AS101 may be a promising antitumour drug for CTCL.     

存活素和皮肤病

存活素是凋亡抑制蛋白家族的新成员,不仅具有抑制细胞凋亡的能力,而且参与细胞有丝分裂和胞质分离的调节。存活素仅表达于各种皮肤良恶性病变,而不表达于正常皮肤。综述存活素分子结构、抑制凋亡的机制、在细胞分裂中的作用、与各种良恶性增生性皮肤病的关系以及靶向治疗。     

皮肤病相关MicroRNAs表达的研究进展

MicroRNAs(miRNAs)是一种大小约18～25个核苷酸的非编码单链小RNA分子,参与包括细胞增殖、分化、凋亡、发育和逆境应答等多种生物学过程。近年来研究发现多种miRNA在皮肤生理生化免疫等过程中发挥了极其重要的作用,在某些皮肤病皮损组织中有异常表达,是皮肤病发生、发展过程中重要的调控因素。本文综述miRNAs的生物合成、作用机制、与皮肤病的相关性及研究前景,有助于进一步了解某些皮肤病的病理生理机制,为开展皮肤病miRNAs的表达及功能研究提供线索,为皮肤病早期诊断和治疗提供新的思路。     

Differential regulation of cyclooxygenase-2 expression by phytosphingosine derivatives, NAPS and TAPS, and its role in the NAPS or TAPS-mediated apoptosis

We investigated the effect of novel phytosphingosine derivatives, N-acetyl phytosphingosine (NAPS) and tetra-acetyl phytosphingosine (TAPS), on induction of apoptosis in HaCaT cells in comparison with C2-ceramide. NAPS/TAPS effectively decreased cell viability in a dose dependent manner mainly due to apoptosis. An apoptosis expression array analysis showed that in the TAPS treated cells 13 genes including COX-2 encoding cyclooxygenase-2, the most induced by TAPS, were up-regulated while 23 others down-regulated. Therefore, we examined the mechanism underlying the altered expression of COX-2. Assays with inhibitors and antibodies against proteins involved in signal transduction demonstrated that NAPS and TAPS elevated COX-2 expression via tyrosine kinase, src, PI-3 kinase and PKC, followed by ERK activation. However, P38 was not involved in the NAPS-mediated COX-2 expression but in the TAPS-mediated. We further demonstrated by FACS analyses that NAPS- or TAPS-mediated apoptosis was greatly increased in cells treated with celecoxib, a selective COX-2 inhibitor. Inhibition of the ERK pathway apparently involved in the NAPS/TAPS-mediated COX-2 expression enhanced the NAPS/TAPS-mediated apoptosis, whereas inhibition of the P38 pathway did not. These results suggest that expression of COX-2 in the TAPS- or NAPS-treated cells may be increased to counteract the effect of those compounds on apoptosis.     

Galectin-3 protects keratinocytes from UVB-induced apoptosis by enhancing AKT activation and suppressing ERK activation

Keratinocytes undergo apoptosis in a variety of physiological and pathological conditions. Galectin-3 is a member of a family of beta-galactoside-binding animal lectins expressed abundantly in keratinocytes and other epithelial cells. Here, we have studied the regulatory role of galectin-3 in keratinocyte apoptosis by using cells from gene-targeted galectin-3 null (gal3(-/-)) mice. We showed that galectin-3 mRNA was transiently upregulated in ultraviolet-B (UVB)-irradiated wild-type keratinocytes. We found that gal3(-/-) keratinocytes were significantly more sensitive to apoptosis induced by UVB as well as various other stimuli, both in vitro and in vivo, than wild-type cells. Moreover, we demonstrated that increased apoptosis in gal3(-/-) keratinocytes was attributable to higher extracellular signal-regulated kinase (ERK) activation and lower AKT activation after UVB irradiation. We conclude that endogenous galectin-3 is an anti-apoptotic molecule in keratinocytes functioning by suppressing ERK activation and enhancing AKT activation and may play a role in the development of apoptosis-related skin diseases.     

Keratinocytes constitutively express the Fas antigen that mediates apoptosis in IFNγ-treated cultured keratinocytes

The Fas antigen is a cell surface protein that can mediate apoptosis in many cell types. Although its physiological function is still unclear, recent evidence indicates that this surface molecule is involved in apoptosis in the immune system and the liver. The epidermis is an organ that undergoes terminal differentiation with the eventual death of keratinocytes, and it has been suggested that this is a specialized form of apoptosis. In the present study, we examined whether or not the Fas antigen is involved in keratinocyte apoptosis. Immunoreactivity for the Fas antigen was found throughout the epidermis in normal human skin sections and cultured normal human keratinocytes, and mRNA for the Fas antigen was found to be constitutively expressed in normal epidermis and cultured normal keratinocytes by RT-PCR analysis. To determine whether the Fas antigen in keratinocytes is functional, we used a cytotoxic monoclonal antibody (mAb) against the Fas antigen to induce apoptosis. This antibody did not induce apoptosis of cultured keratinocytes even though they expressed the Fas antigen. We then tested the ability of several cytokines (TGF, TNF and IFN) to induce Fas-mediated keratinocyte apoptosis. Only pretreatment with IFN followed by the addition of the anti-Fas mAb induced apoptosis, as assessed by cell viability, morphological changes and ultrastructural characteristics, suggesting that constitutive expression of the Fas antigen is not sufficient to induce apoptosis in keratinocytes and that keratinocyte apoptosis via the Fas antigen-mediated mechanism may require the activation of keratinocytes by IFN, which is thought to be produced by activated T cells. The Fas antigen may not be related to keratinocyte apoptosis that occurs in terminal differentiation, but rather to the apoptosis that occurs in inflammatory skin diseases.     

Unraveling the mysteries of IGF-1 signaling in melanoma

The inherent ability of a cell to undergo apoptosis governs a number of developmental processes essential to proper mammalian development. Into adulthood, the pathways that potentiate the apoptotic response are extremely diverse and finely regulated to prevent potential diseases. Of these, cancer is often associated with loss of an apoptotic response. Hanahan and Weinberg (2000) list evasion of apoptosis as a hallmark feature acquired during neoplastic transformation. The impact of this event is dramatic on several levels; avoidance of apoptosis not only prevents programmed cell death in an array of cell types but also promotes chemotherapeutic resistance during anticancer regimens.     

COX-2抑制剂NS398对人鳞状细胞癌Tca8113细胞株生长和凋亡的影响

目的 探讨COX-2抑制剂NS398对鳞状细胞癌细胞Tca8113生长及凋亡的影响。方法 细胞培养加入NS398作用后,采用噻唑蓝（MTT） 法观察NS398 对Tca8113细胞增殖的影响,流式细胞仪及透射电镜研究NS398对Tca8113细胞周期和凋亡的作用。结果 MTT比色法显示NS398能抑制Tca8113细胞的生长,呈浓度和时间依赖性。流式细胞仪检测结果显示NS398干预细胞出现典型的亚二倍体"凋亡峰";G0 /G1期细胞比例升高,S期和G2 /M期比例下降。电镜下见典型的凋亡形态学改变。结论COX-2抑制剂NS398在体外可通过诱导凋亡有效抑制Tca8113细胞的生长。