毛囊干细胞向黑素细胞系定向分化调控机制的研究进展

毛囊干细胞包含神经嵴来源的成体干细胞,具有多向分化潜能.利用毛囊干细胞模型,可以深入研究从神经嵴干细胞到成熟黑素细胞的定向分化过程和掌握黑素细胞前体阶段发育分化的调控机制,从而为理解色素性疾病的发生发展和恢复提供新的理论依据.概述近年来调控毛囊干细胞向黑素细胞系定向分化的相关细胞因子和信号通路的进展,以期为色素性皮肤病的发病和治疗发展提供新的方向和突破口.

Abstract：

Hair follicle stem cells contains pluripotent adult stem cells derived from the neural crest.With the experimental model of hair follicle stem cells,further studies could be carried out on the directed differentiation process of neural crest-derived stem cells into mature melanocytes,and on the regulatory mechanisms of melanocyte precursor differentiation,which will provide theoretical evidence for the understanding of development and recovery of pigmentary skin diseases.This article focuses on the recent advances in cytokines and signaling pathways regulating the differentiation from hair follicle stem cells into melanocyte lineage,which may provide directions for studies on the pathogenesis and treatment of pigmentary skin disorders.     

水通道蛋白-3与皮肤研究进展

Aquaporins (AQPs) are a group of membrane transport proteins involved in the transport ofwater across cell membranes. AQP3, the most abundant aquaporin subset in human skin, is permeable notonly to water but also to small solutes such as glycerol. It has been reported that AQP3-knockout mice havereduced stratum corneum water content, elasticity and impaired wound healing. AQP3 has been revealed to berelated to cell proliferation and migration, and involved in the initiation, progression and metastasis of tumors.In addition, AQP3 expression is associated with the pathogenesis of inflammatory cutaneous diseases such asatopic dermatitis and erythema toxicum neonatorum. AQP3 expression can be modulated by multiple factorssuch as retinoic acid and tumor necrosis factor α, and this modulation may provide a new clue for the therapyof related skin diseases.     

Study of substance P and its receptor neurokinin-1 in psoriasis and their relation to chronic stress and pruritus

Substance P and its receptor(R) neurokinin (NK)-1 may have a role in the pathogenesis of psoriasis. Stress has been reported to play a role in the onset and exacerbation of psoriasis, which might include the substance P-NK-1 receptor(R) pathway. A feature of psoriasis, that has been correlated to the severity of stress and secretion of substance P, is pruritus. The objective of this study was to investigate the expression of substance P and the NK-1R in involved and noninvolved psoriatic skin, using a biotinylated streptavidin technique. Moreover, a possible correlation between the patient′s level of chronic stress, measured by salivary cortisol samples, degree of lesional pruritus, measured by means of a visual analogue scale, and the expression of substance P- and the NK-1R, was investigated. There was a low number of substance P positive nerve fibres in noninvolved and involved skin, the major immunoreactivity for substance P being found in inflammatory cells. The number of substance P- and NK-1R positive inflammatory cells was increased in involved compared to noninvolved psoriatic skin. The substance P positive cells were mostly lymphocytes, while most of the NK-1R positive cells were mast cells. NK-1R immunoreactivity was also seen as a reticular pattern in the upper part of the epidermis of involved skin in the majority of the patients. Low cortisol ratios in the patients, being an indicator of chronic stress, were correlated to an increased number of substance P- and NK-1R positive inflammatory cells in noninvolved psoriatic skin, and higher cortisol ratios to the presence of keratinocyte NK-1R immunoreactivity in involved skin. The degree of pruritus could not be correlated to the number of substance P positive fibers nor cells. Nonneuronal substance P and its receptor NK-1 might have a role in psoriasis, also during chronic stress.     

Human β-defensin-2 and skin diseases

Human β-defensin-2 (hBD-2) is an endogenous antimicrobial peptide recently found in the skin with broad-spectrum antimicrobial activity and unique mechanism of function. Recent studies have confirmed that the expression of hBD-2 is upregulated in the lesions of some dermatoses, such as psoriasis,acne vulgaris, verruca, dermatophytosis and basal cell carcinoma, etc. The susceptibility to bacterial and viral infections may be associated with the decreased or absent expression of hBD-2. Further researches into HBD-2will provide a new direction for the prevention and treatment of skin diseases.     

Photodynamic therapy with topical aminolevulinic acid

Photodynamic therapy(PDT) is a relatively new therapy in dermatology that uses the topical application of a porphyrin derivative to selectively destroy a cutaneous target. The action is implemented by the application of a specific light frequency. The ability of porphyrin to selectively target tumor tissue has been known since the 1960 s. In the late 1970 s, the underlying mechanism was defined, and Dougherty's discovery of the first chromophore led to the production and commercialization of Photofrin. Many other chromophores that can act as photosensitizers have been studied since then, with aminolevulinic acid currently the most commonly used chromophore in clinical practice. PDT is simple, minimally invasive and can be administered on an outpatient basis. The efficacy of PDT has been proven for actinic keratosis, Bowen's disease and basal cell carcinoma; another of its well-known applications is the treatment of photoaging. Indications for its use are continuously increasing, and promising results are reported for various skin diseases. In this paper we report the mechanism of action of PDT with aminolevulinic acid, the literature concerning the most common diseases treated with PDT and the subsequent level of evidence.     

皮肤细胞DNA光损伤后反应机制研究进展

紫外线可引起皮肤细胞DNA损伤,诱发皮肤肿瘤和光老化.DNA损伤类型包括:DNA单链断裂、链间交联、核苷酸碱基修饰等.细胞拥有DNA损伤后反应机制以维持基因组稳定,如细胞周期监控点、DNA修复和细胞早衰等.细胞周期监控系统检测到染色体结构异常时将引起细胞周期停滞并启动修复进程;而在检测到无法修复的损伤时则会诱使细胞衰老.因此皮肤光老化也是一种预防肿瘤发生的防御机制,ATR-Chk1信号通路在其中起着关键的调控作用.

Abstract：

Ultraviolet radiation can induce DNA damage in skin cells, cause skin tumors and accelerate skin photoaging. UV-induced DNA damage in skin cells includes DNA single strand breaks, DNA interstrand cross-links and nucleotide base modifications. Skin cells could exert DNA damage responses, such as cell cycle checkpoints, DNA repair and premature senescence to prevent genomic instability. When cell cycle checkpoint systems sense the abnormal chromosomal DNA structures, they execute cell cycle arrest and DNA repair process will be initiated. Cellular senescence is also executed by checkpoint responses when unrepairble and extensive chromosomal abnormalities are detected. So skin photoaging is thought to be one of the major mechanisms against skin carcinogenesis. ATR-Chk1 signaling pathway plays a key role in the regulation of DNA damage response process.     

Sweet side of bladder cancer

The malignant transformation of cells is often accompanied by deranged expression of the sugar chains,i.e.,glycans,attached the cancer cell surfaces or attached to secreted proteins.The aberrant expression of specific glycans in bladder cancer has also been reported by several research groups.Similarly to other cancers,glycans such as the sialyl Tn antigens have been suggested as diagnostic and prognostic biomarkers of bladder cancer,and associated with disease progression and patient’s response to treatment.At present our understandings about the role of glycans in bladder cancer is still limited,but at the same time it is now assumed that this understanding urges and it will fuel the development of novel strategies of diagnostic and therapy.     

人皮肤鳞状细胞癌A431细胞株电压门控钾通道的研究

目的 探讨电压门控钾通道在人皮肤鳞状细胞癌A431细胞和人角质形成细胞HaCaT细胞中的作用.方法 噻唑蓝方法研究加入含有不同浓度四乙胺的培养基对A431细胞和HaCaT细胞的增殖的影响;提取体外培养A431细胞、HaCaT细胞以及人正常表皮组织的蛋白,ELISA方法检测电压门控钾通道蛋白(HERG)在它们中的表达,比较它们的差异.结果 四乙胺对体外培养的A431细胞和HaCaT细胞的增殖抑制效应具有时间依赖与剂量依赖的特点,当四乙胺的浓度≥10 mmol/L且作用时间≥24 h,可以使A431细胞和HaCaT细胞的增殖受到明显的抑制.HERG钾通道蛋白在A431细胞、HaCaT细胞和人正常皮肤表皮组织均有表达,平均浓度分别为(49.7114±3.55696)pg/ml、(35.7471±4.14696)pg/ml、(36.8857±3.47810)pg/ml,组间比较差异具有统计学意义(P<0.05).结论 阻断电压门控钾通道可抑制A431细胞和HaCaT细胞的增殖;电压门控钾通道可能在人皮肤鳞状细胞癌细胞上的表达更显著.

Abstract：

Objective To investigate the role of voltage-gated potassium channel in the human skin squamous cell carcinoma A431 cells and human keratinocyte HaCaT cells. Methods MTT assay was performed to detect the effect of different concentrations of tetraethylammonium (TEA) on the proliferation of cultured A431 cells and HaCaT cells. Besides, enzyme-linked immunosorbent assay (ELISA) was conducted to detect the expression of HERG channel protein in A431 cells, HaCaT cells and normal human skin tissue.Results TEA inhibited the proliferation of A431 cells and HaCaT cells in a dose- and time-dependent manner.After treated with TEA (≥ 10 mmol/L) for 24 or more hours, the proliferation of A431 cells and HaCaT cells was obviously suppressed. A significant difference was observed in the average concentration of HERG channel protein between A431 cells, HaCaT cells and normal human skin tissue (49.7114 ± 3.55696 pg/ml, 35.7471 ±4.14696 pg/ml, 36.8857 ± 3.47810 pg/ml, all P < 0.05). Conclusions The block of voltage-gated potassium channel could inhibit the proliferation of A431 cells and HaCaT cells, and the expression of voltage-gated potassium channel seems to be higher in human skin squamous cell carcinoma cells.     

Preclinical therapy of benign prostatic hyperplasia with neuropeptide hormone antagonists

Benign prostatic hyperplasia(BPH)is a pathologic condition of the prostate described as a substantial increase in its number of epithelial and stromal cells.BPH may significantly reduce the quality of life due to the initiation of bladder outlet obstruction and lower urinary tract syndromes.Current medical therapies mostly consist of inhibitors of 5α-reductase orα1-adrenergic blockers;their efficacy is often insufficient.Antagonistic analogs of neuropeptide hormones are novel candidates for the management of BPH.At first,antagonists of luteinizing hormone-releasing hormone(LHRH)have been introduced to the therapy aimed to reduce serum testosterone levels.However,they have also been found to produce an inhibitory activity on local LHRH receptors in the prostate as well as impotence and other related side effects.Since then,several preclinical and clinical studies reported the favorable effects of LHRH antagonists in BPH.In contrast,antagonists of growth hormone-releasing hormone(GHRH)and gastrin-releasing peptide(GRP)have been tested only in preclinical settings and produce significant reduction in prostate size in experimental models of BPH.They act at least in part,by blocking the action of respective ligands produced locally on prostates through their respective receptors in the prostate,and by inhibition of autocrine insulin-like growth factors-Ⅰ/Ⅱand epidermal growth factor production.GHRH and LHRH antagonists were also tested in combination resulting in a cumulative effect that was greater than that of each alone.This article will review the numerous studies that demonstrate the beneficial effects of antagonistic analogs of LHRH,GHRH and GRP in BPH,as well as suggesting a potential role for somatostatin analogs in experimental therapies.     

变应性接触性皮炎免疫学发病机制研究进展

变应性接触性皮炎发病机制非常复杂,近来研究有新的发现,其中表皮角质形成细胞除促进T细胞的浸润外,还有限制该病发展的作用;皮肤树突细胞除执行抗原提呈作用外,可能还有免疫调节作用.还发现有新的免疫细胞和分子参与作用,如CD4+CD25+Foxp3+T细胞在其中发挥免疫抑制功能;Th17细胞介导、促进炎症反应;B10细胞通过IL-10依赖机制有负调节作用.一些黏附分子及其配基(PSGL-1等)和趋化因子(CCL21等)在发病中也起着一定作用.

Abstract：

The pathogenesis of allergic contact dermatitis (ACD) is very complicated. However, new discoveries have been made on the topic in recent studies. Epidermal keratinocytes not only promote T cell infiltration, but also limit the development of ACD. In addition, cutaneous dendritic cells possess both antigen presenting function and immunomodulatory activity. Furthermore, some immune cells and molecules have been newly demonstrated to be involved in the pathogenesis. For example, CD4+ CD25+ Foxp3+ T cells play a powerful immunosuppression role; T helper 17 (Th17) cells mediate and enhance inflammation reaction; B10 cells play a negative regulatory effect via an interleukin (IL)-10-dependent mechanism. Some adhesion molecules and their ligand (such as PSGL-1), as well as chemokines (such as CCL21) also exert a certain role in the pathogenesis of ACD.     

Mesenchymale Stammzellen der Haut

Within the next decade stem cell-based therapies can be expected to be part of clinical medicine. In regard to the skin, the focus of stem cell research is on the epidermis and the hair follicle. In 2001, mesenchymal stem cells residing within the dermis were first isolated which have the capacity to differentiate into adipocytes, smooth muscle cells, osteocytes, chondrocytes and even neurons and glia as well as hematopoietic cells of myeloid and erythroid lineage. The perifollicular connective tissue sheath and the papilla represent the likely anatomical niche for these multipotent dermal cells. They have the potential to function as an easily accessible, autologous source for future stem cell transplantation. Potential therapeutic applications include the treatment of acute and steroid-refractory graft-versus-host disease, systemic lupus erythematosus, idiopathic pulmonary fibrosis and arthritis. The neuronal differentiation potential of cutaneous mesenchymal stem cells may also be exploited in the treatment of neurodegenerative disorders and traumatic spinal injury. The most immediate impact can be expected in the field of wound healing.     

Dermatofibrosarcoma protuberans: a tumour of nestin‐positive cutaneous mesenchymal stem cells?

Background There is an increasing body of evidence suggesting that malignancies arise from mutated stem cells, which has led to the formulation of the cancer stem cell hypothesis. It has also been suggested that cutaneous malignancies originate from a mutated stem cell. To date, mesenchymal tumours of the skin have not been the focus of the cancer stem cell hypothesis. A population of mesenchymal stem cells has recently been identified in the dermal compartment of the skin. These proposed stem cells are positive for the neuroepithelial stem cell marker nestin. Objectives  To describe the expression pattern of nestin, a neuroepithelial stem cell protein, in dermatofibrosarcoma protuberans (DFSP). Methods Immunohistochemical evaluation of DFSP with a monoclonal antibody against nestin was performed using standard techniques. For comparison we also analysed dermatofibromas (DF). In addition, we used antibodies against CD34 and Factor XIIIa; the proliferation marker Ki67 was also used. Results Strong immunoreactivity for nestin was found in DFSP whereas all DF cases were nestin‐negative. Conclusions We propose that DFSP may represent a clonal expansion of a nestin‐positive mesenchymal stem cell which would put this tumour in line with other neoplasms for which the cancer stem cell hypothesis was formulated. We suggest the use of nestin as an additional marker for DFSP, especially in cases of negative immunoreactivity for CD34. Nestin may also be employed for margin evaluation of DFSP in micrographic (Mohs) surgery.     

皮肤间充质干细胞在促进皮肤愈合中的作用

间充质干细胞(mesenchymal stem cells,MSCs)是当前干细胞研究的热点之一。目前,皮肤愈合正逐渐受到重视。现有的研究认为骨髓间充质干细胞(BM-MSCs)能从多个方面促进皮肤愈合,如促进表皮生长、促进真皮成纤维细胞的增生等。皮肤间充质干细胞(SMSCs)和BM-MSCs均为MSCs,具有很多的相似性,且SMSCs较BM-MSCs更容易得到。所以可从目前对BM-MSCs的研究预测到SMSCs在皮肤创伤愈合中的研究前景,且将来很可能会替代BM-MSCs。     

Management of severe epidermolysis bullosa by haematopoietic transplant: principles,perspectives and pitfalls

People with severe forms of epidermolysis bullosa (EB) develop widespread blistering and progressively debilitating multisystem complications that may result in a shortened lifespan. As some wounds in EB individuals are difficult or impossible to access with topical therapy, we examined the potential of systemic therapy with normal haematopoietic stem cells. In both animal models and children with EB, healthy donor cells from the haematopoietic graft migrated to the injured skin; simultaneously, there was an increase in the production of skin‐specific structural proteins deficient in EB, increased skin integrity and reduced tendency to blister formation. Even though the majority of evaluable individuals have had a positive response in skin healing, frequently changing their quality of life, the improvement in lifestyle has been varied and the overall clinical response incomplete. To change the current amelioration of disease into a full cure, we propose to (i) increase safety as well as efficacy of haematopoietic cell transplant (HCT) using co‐infusion of mesenchymal stromal/stem cells with haematopoietic stem cells and non‐myeloablative conditioning for transplant; (ii) optimize homing of donor cells into the skin erosions in animal models of EB; and (iii) discover and test new drugs for EB therapy using patient‐specific induced pluripotent stem cells. We conclude that although HCT has always been a risky treatment restricted to those with serious life‐threatening or debilitating diseases, by most benchmarks, the results of HCT in EB have shown that HCT has the potential of being a durable, systemic therapy for people with severe forms of EB.     

Cutaneous mesenchymal stem cells: status of current knowledge,implications for dermatopathology

Stem cell biology is currently making its impact on medicine, which will probably increase over the next decades. It not only influences our therapeutic thinking caused by the enormous plasticity of stem cells but also affects diagnostic and conceptual aspects of dermatopathology. Although our knowledge of the keratinocytic stem cells located within the follicular bulge has exploded exponentially since their discovery in 1990, the concept of cutaneous mesenchymal stem cells (MSCs) is new. Described initially in 2001 in mice, MSCs later were also found in the human dermis. The connective tissue sheath and the papilla of the hair follicle probably represent the anatomical niche for cutaneous MSCs. In line with the cancer stem cell hypothesis, mutations of these cells may be the underlying basis of mesenchymal skin neoplasms, such as dermatofibrosarcoma protuberans. Furthermore, research on cutaneous MSCs may impact our thinking on the interaction of the epithelial component of skin neoplasms with their surrounding stroma. We are only in the early stages to recognize the importance of the potential contributions of cutaneous MSC research to dermatopathology, but it is not inconceivable to assume that they could be tremendous, paralleling the early discovery of the follicular bulge as a stem cell niche. Sellheyer K, Krahl D. Cutaneous mesenchymal stem cells: status of current knowledge, implications for dermatopathology.     

Multilineage differentiation potential of human dermal skin-derived fibroblasts

Dermal skin-derived fibroblasts from rodent and human have been found to exhibit mesenchymal surface antigen immunophenotype and differentiation potential along the three main mesenchymal-derived tissues: bone, cartilage and fat. Human dermal skin-derived mesenchymal stem cells constitute a promising cell source in clinical applications. Therefore, we isolated fibroblastic mesenchymal stem-cell-like cells from human dermis derived from juvenile foreskins, which share a mesenchymal stem cell phenotype and multi-lineage differentiation potential. We could show similar expression patterns for CD14(-), CD29(+), CD31(-), CD34(-), CD44(+), CD45(-), CD71(+), CD73/SH3-SH4(+), CD90/Thy-1(+), CD105/SH2(+), CD133(-) and CD166/ALCAM(+) in well-established adipose tissue derived-stem cells and fibroblastic mesenchymal stem-cell-like cells by flow cytometry. Immunostainings showed that fibroblastic mesenchymal stem-cell-like cells expressed vimentin, fibronectin and collagen; they were less positive for alpha-smooth muscle actin and nestin, while they were negative for epithelial cytokeratins. When cultured under appropriate inducible conditions, both cell types could differentiate along the adipogenic and osteogenic lineages. Additionally, fibroblastic mesenchymal stem-cell-like cells demonstrated a high proliferation potential. These findings are of particular importance, because skin or adipose tissues are easily accessible for autologous cell transplantations in regenerative medicine. In summary, these data indicate that dermal fibroblasts with multilineage differentiation potential are present in human dermis and they might play a key role in cutaneous wound healing.     

脂肪干细胞在皮肤光老化中的作用

脂肪干细胞是存在于脂肪组织中的一种成体干细胞，具有来源丰富、可反复取材、痛苦小、易扩增、能安全植入同体或异体等优点，已成为组织工程理想的种子细胞。基于其多潜能分化和旁分泌功能，新近认为是继胚胎干细胞、骨髓干细胞之后的又一热点。已发现脂肪干细胞及其可溶性因子具有促进伤口愈合、促进成纤维细胞增殖、抗氧化、抗皱纹、美白皮肤等作用，在皮肤抗衰老领域有应用潜力。     

Perivascular localization of dermal stem cells in human scalp

In mammalian skin, the existence of stem cells in the dermis is still poorly understood. Previous studies have indicated that mesenchymal stem cells (MSCs) are situated as pericytes in various mammalian tissues. We speculated that the human adult dermis also contains MSC-like cells positive for CD34 at perivascular sites similar to adipose tissue. At first, stromal cells from adult scalp skin tissues showed colony-forming ability and differentiated into mesenchymal lineages (osteogenic, chondrogenic and adipogenic). Three-dimensional analysis of scalp skin with a confocal microscope clearly demonstrated that perivascular cells were positive for not only NG2, but also CD34, immunoreactivity. Perivascular CD34-positive cells were abundant around follicular portions. Furthermore, CD34-positive cell fractions collected with magnetic cell sorting were capable of differentiating into mesenchymal lineages. This study suggests that dermal perivascular sites act as a niche of MSCs in human scalp skin, which are easily accessible and useful in regenerative medicine.     

Stem cell and skin rejuvenation

Stem cell-based therapies have been widely used for their abilities to repair and regenerate different types of tissues and organs in cosmetic and plastic surgeries. It involves the clinical application of different types of stem cells. Different stem cells have been reported to be applicable in different areas of cosmetic surgeries like face lipoatrophy, skin rejuvenation, breast enhancement, and body contouring. However, adipose-derived stem cells remain the most widely used by cosmetic surgeons as they have the potential and capability to differentiate into mesenchymal, ectodermal, and endodermal lineages and are easily accessible to harvest. The purpose of this review is to summarize available applications of stem in cosmetic and plastic surgeries.     

Mesenchymal stem cell therapy in skin: why and what for?

In recent years, few stem cells have gained as much clinical notoriety as mesenchymal stem cells. Indeed, MSCs are already in use for a range of systemic inflammatory and autoimmune conditions that also affect the skin, such as acute and chronic graft versus host disease or lupus erythematosus. Most interestingly, these cells are able to improve skin wound healing in multiple preclinical models and few patient series. An additional potential of these cells is the delivery of missing structural elements in skin inherited disorders. However, we here contend that MSCs are not appropriate for cell replacement therapies in the context of wound healing. Indeed, engraftment of cells in the dermis is poor in the absence of irradiation and the observed effects seem mainly due to paracrine factors. In this viewpoint, we favour the hypothesis of a replete niche and competition with resident mesenchymal populations in the dermis not allowing the engraftment of newly delivered MSCs. Consequently, we propose that the benefit of MSCs may be at least in part reproduced by the growth factors or immunomodulatory molecules that they produce. In any case, the rapid progress in this field has allowed the emergence of important questions in skin biology that need to be addressed in parallel with the predictable future use of MSCs in the clinic.