Neuronal RA175/SynCAM1 isoforms are processed by tumor necrosis factor-alpha-converting enzyme (TACE)/ADAM17-like proteases

RA175/SynCAM1, a member of immunoglobulin superfamily 4 (Igsf4; recently named Cadm1), is a cell adhesion molecule involved in the formation of a functional synapse. Little is known about the modulation of RA175/SynCAM1-mediated synaptic formation and plasticity. Neurons express two major isoforms containing exons 7-8a-8b-9 and exons 7-8b-9. We found that these isoforms were processed within an 11-amino acid sequence, encoded by exon 8b, near the transmembrane domain. TNF-alpha protease inhibitor-1 (TAPI-1) blocked the processing of RA175/SynCAM1 (exons 7-8a-8b-9). Furthermore, TAPI-1 increased the number of synaptophysin and RA175/SynCAM1 colocalization on the dendrites of neurons. Non-cleaved RA175/SynCAM1 was located at the synapse and membrane-bound, cleaved fragments were detected at the non-synaptic region of dendrites. These results suggest that tumor necrosis factor-alpha-converting enzyme (TACE)/ADAM17-like proteases play a role in synaptic formation to generate specific neuronal connections by processing the excess amount of RA175/SynCAM1 located in the non-synaptic region.     

Brief clinical report: duplication of distal 17q: report of an observation

We describe a boy with the syndrome due to dup(17q) resulting from a paternal balanced t(12;17) (q24;q23). The comparison of the clinical findings in our patient with those previously reported shows that the dup(17q23----qter) is associated with a clinically recognizable syndrome. Anomalies present in greater than or equal to 75% of the patients were severe psychomotor retardation; short stature; microcephaly; frontal bossing and temporal retraction; widow's peak; narrow palpebral fissures; flat nasal bridge; thin upper lip overlapping thin lower lip; downturned corners of the mouth; apparently low-set, posteriorly angulated and malformed ears; low posterior hairline; widely spaced nipples; cryptorchidism; proximal limb shortness; and hyperlaxity of limb joints. The translocation carrier father of our patient had a Poland anomaly.     

Disruption of the endopeptidase ADAM10-Notch signaling axis leads to skin dysbiosis and innate lymphoid cell-mediated hair follicle destruction

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A highly enriched niche of precursor cells with neuronal and glial potential within the hair follicle dermal papilla of adult skin

Skin-derived precursor cells (SKPs) are multipotent neural crest-related stem cells that grow as self-renewing spheres and are capable of generating neurons and myelinating glial cells. SKPs are of clinical interest because they are accessible and potentially autologous. However, although spheres can be readily isolated from embryonic and neonatal skin, SKP frequency falls away sharply in adulthood, and primary sphere generation from adult human skin is more problematic. In addition, the culture-initiating cell population is undefined and heterogeneous, limiting experimental studies addressing important aspects of these cells such as the behavior of endogenous precursors in vivo and the molecular mechanisms of neural generation. Using a combined fate-mapping and microdissection approach, we identified and characterized a highly enriched niche of neural crest-derived sphere-forming cells within the dermal papilla of the hair follicle of adult skin. We demonstrated that the dermal papilla of the rodent vibrissal follicle is 1,000-fold enriched for sphere-forming neural crest-derived cells compared with whole facial skin. These "papillaspheres" share a phenotypic and developmental profile similar to that of SKPs, can be readily expanded in vitro, and are able to generate both neuronal and glial cells in response to appropriate cues. We demonstrate that papillaspheres can be efficiently generated and expanded from adult human facial skin by microdissection of a single hair follicle. This strategy of targeting a highly enriched niche of sphere-forming cells provides a novel and efficient method for generating neuronal and glial cells from an accessible adult somatic source that is both defined and minimally invasive.     

Dissecting the impact of chemotherapy on the human hair follicle: a pragmatic in vitro assay for studying the pathogenesis and potential management of hair follicle dystrophy

Chemotherapy-induced alopecia represents one of the major unresolved problems of clinical oncology. The underlying molecular pathogenesis in humans is virtually unknown because of the lack of adequate research models. Therefore, we have explored whether microdissected, organ-cultured, human scalp hair follicles (HFs) in anagen VI can be exploited for dissecting and manipulating the impact of chemotherapy on human HFs. Here, we show that these organ-cultured HFs respond to a key cyclophosphamide metabolite, 4-hydroperoxycyclophosphamide (4-HC), in a manner that resembles chemotherapy-induced HF dystrophy as it occurs in vivo: namely, 4-HC induced melanin clumping and melanin incontinence, down-regulated keratinocyte proliferation, massively up-regulated apoptosis of hair matrix keratinocytes, prematurely induced catagen, and up-regulated p53. In addition, 4-HC induced DNA oxidation and the mitochondrial DNA common deletion. The organ culture system facilitated the identification of new molecular targets for chemotherapy-induced HF damage by microarray technology (eg, interleukin-8, fibroblast growth factor-18, and glypican 6). It was also used to explore candidate chemotherapy protectants, for which we used the cytoprotective cytokine keratinocyte growth factor as exemplary pilot agent. Thus, this novel system serves as a powerful yet pragmatic tool for dissecting and manipulating the impact of chemotherapy on the human HF.     

Polymorphisms of the tumor necrosis factor-alpha (TNF) and the TNF-alpha converting enzyme (TACE/ADAM17) genes in relation to cardiovascular mortality: the AtheroGene study

Tumor necrosis factor (TNF) is a major cytokine involved in inflammatory reaction and a mortality predictor in patients with coronary artery disease (CAD). Plasma levels of soluble TNF (sTNF) depend on the rate of its synthesis but also on its shedding from cell surface, a mechanism mainly regulated by the TNF alpha converting enzyme (TACE or ADAM17). We investigated the relationship between ADAM17 and TNF polymorphisms, circulating levels of shed ADAM17 substrates (sTNF, sTNFR1 and sTNFR2), and cardiovascular risk in a prospective cohort of CAD patients. Five tag single-nucleotide polymorphisms (SNPs) of the ADAM17 gene as well as four previously described TNF SNPs were genotyped in the Atherogene Study composed of 1,400 CAD patients among which 136 died from a cardiovascular (CV) cause. sTNF, sTNFR1, and sTNFR2 concentrations were all significantly elevated in patients with future CV death, independently of other clinical/biological variables. While none of the studied TNF SNPs was associated with sTNF, sTNFR1, nor sTNFR2 levels, the ADAM17 −154A allele was found associated with a 14% increase of sTNF levels as compared to the −154C allele (p = 0.0066). Moreover, individuals carrying the 747Leu allele displayed a borderline increased risk of future cardiovascular death [odds ratio, 2.06 (1.05–4.04), p = 0.03]. These results suggest a role of ADAM17 in the regulation of sTNF plasma levels and identifies ADAM17 gene as a candidate for CAD. Tumor necrosis factor (TNF) is a major cytokine involved in inflammatory reaction and a mortality predictor in patients with coronary artery disease (CAD). We have studied the association of ADAM17 and TNF polymorphisms with circulating levels of shed ADAM17 substrates (sTNF, sTNFR1 and sTNFR2) and with cardiovascular risk in a large population of individuals with CAD (Atherogene Study, n = 1,400). Two newly identified polymorphisms, obtained by a systematic sequencing of the ADAM17 gene, C-154A and Ser747leu, slightly influence respectively sTNF plasma levels and the risk of cardiovascular death. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

The critical roles of serum/glucocorticoid-regulated kinase 3 (SGK3) in the hair follicle morphogenesis and homeostasis: the allelic difference provides novel insights into hair follicle biology

Mutation in the serum/glucocorticoid regulated kinase 3 (Sgk3, also known as Sgkl or Cisk) gene causes both defective hair follicle development and altered hair cycle in mice. We examined Sgk3-mutant YPC mice (YPC-Sgk3(ypc)/Sgk3(ypc)) and found expression of SGK3 protein with altered function. In the hair follicles of YPC mice, the aberrant differentiation and poor proliferation of hair matrix keratinocytes during the period of postnatal hair follicle development resulted in a complete lack of hair medulla and weak hair. Surprisingly, the length of postnatal hair follicle development and anagen term was shown to be dramatically shortened. Also, phosphorylation of GSK3beta at Ser9 and the nuclear accumulation of beta-catenin were reduced in the developing YPC hair follicle, suggesting that phosphorylation of GSK3beta and WNT-beta-catenin pathway takes part in the SGK3-dependent regulation of hair follicle development. Moreover, the above-mentioned features, especially the hair-cycling pattern, differ from those in other Sgk3-null mutant strains, suggesting that the various patterns of dysfunction in the SGK3 protein may result in phenotypic variation. Our results indicate that SGK3 is a very important and characteristic molecule that plays a critical role in both hair follicle morphogenesis and hair cycling.     

毛囊细胞--一种新的皮肤组织工程种子细胞

毛囊的上皮细胞和真皮细胞与皮肤的表皮角朊细胞和真皮成纤维细胞具有很大的相似性,但其具有更强的增殖分化能力和更多的生物学特性,并且毛囊真皮细胞具有干细胞的一些特性,作为皮肤组织工程的种子细胞具有更独特的优势,在构建带有皮肤附属器的组织工程皮肤上有潜在的前景.     

C57BL/6小鼠皮肤毛囊发育的实验研究

目的探讨胎鼠,乳鼠和成鼠毛囊发育的规律。方法石蜡和冰冻超薄切片,采用HE染色,AP活性染色,油红O染色,凋亡细胞鉴定等方法观察不同时期C57BL/6小鼠毛囊的发育情况。结果胚胎发育第15.5d(E15.5)开始出现毛囊,至E18.5胎鼠背部皮肤逐渐增厚,毛囊逐渐增多。乳鼠出生第1d毛囊大部分处于第4阶段之前,毛囊数量继续增加,至出生第4d皮肤基底层未见新生的毛囊,此时毛囊数量维持不变,出生第9d毛囊达到第8阶段。成鼠脱毛后第9d约有95%的毛囊进入生长Ⅳ期,第17d约有63.3%的毛囊进入退化期,第22d约有85%的毛囊处于退化期。结论小鼠毛囊的早期发育起始于E15.5,从E17.5到出生后3d毛囊数量呈快速增加趋势,因此,这一时期可以用于探讨毛囊再生机制等相关研究。     

Alopecia areata: a tissue specific autoimmune disease of the hair follicle

The goal of this review is to introduce the immunologic community to alopecia areata as a model system for the study of tissue directed autoimmune disease. Alopecia areata is marked by autoimmune assault on the hair follicle resulting in hair loss. It is linked to HLA-DQ3 and evidence suggests it is mediated by T-lymphocytes with a TH1 cytokine profile. Hair follicles are an immune protected site with deficient MHC expression. Evidence is presented suggesting that alopecia areata results from loss of immune privilege with presentation of autoantigens. Alopecia areata is one of the most common human autoimmune conditions, with a lifetime risk of approximately 1.7%. Study of alopecia areata in humans is facilitated by the accessibility of scalp for biopsy. It is possible to transfer the condition with lesional human lymphocytes in a human scalp graft/SCID mouse model. There are also spontaneous animal models which share the features of the human condition. For these reasons, alopecia areata is a powerful model for study of the induction and pathogenesis of tissue directed autoimmune disease.     

Heterozygote detection in glucose-6-phosphate dehydrogenase deficiency: limitation of hair follicle analysis

Glucose-6-phosphate dehydrogenase deficiency was demonstrated in a case of favism. The X-linked enzyme defect was expressed in erythrocytes but not in hair root cells. Predictably, the mother shown to be a heterozygous carrier on the basis of intermediate erythrocyte glucose-6-phosphate dehydrogenase activity could not be identified as a carrier by means of hair root study. It seems to be necessary to test the hair roots of at least one enzyme-deficient member of the family to exclude false negative results, if hair root analysis is used for carrier detection. Because of the more or less clonal origin of hair roots, they remain a convenient biopsy material with which to study heterozygosity in X-linked inborn errors of metabolism.     

微环境调控毛囊干细胞增殖与分化的研究进展

毛囊干细胞生存的微环境改变使毛囊干细胞的增殖、分化也发生改变。微环境对干细胞的调控是通过信号转导通路及一些重要的信号分子实现的,如整合素家族、Wnt和Notch信号转导通路及c-myc基因和β-连环蛋白等。     

组织块法与酶消化法培养大鼠毛囊干细胞的比较

背景：研究证实毛囊干细胞比毛囊间表皮干细胞更有增生能力,近年来受到广泛关注,成为种子细胞的研究热点。 目的：比较组织块法和两步酶法培养大鼠毛囊干细胞的生物学特性。 方法：体式显微镜下分离大鼠触须部的毛囊,分别用组织块法和两步酶法培养毛囊干细胞,利用反复差速贴壁法纯化细胞,定期观察细胞生长状况及形态,流式细胞仪检测第3代毛囊干细胞CD34、β1整合素的表达。 结果与结论：两步酶法获得的细胞生长速度快,获得的细胞量多,而组织块法获得的细胞生长速度较慢,获得的细胞量也少。流式细胞仪分析显示酶消化法培养组PE-CD34、FITC-β1整合素的表达分别为(39.52±19.57)%和(93.46±4.73)%,组织块法培养组相应为(19.20±11.53)%和(363.57±14.42)%,两组间差异有显著性意义(P < 0.05)。总的来说,两种方法均能培养出实验所需毛囊干细胞,可根据不同实验需求选择恰当的培养方法。中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程全文链接：     

Estrogen upregulates MICA/B expression in human non-small cell lung cancer through the regulation of ADAM17

Estrogen is involved in promoting lung cancer cell division and metastasis. MICA and MICB function as ligands for NKG2D, an important immunoreceptor expressed on natural killer (NK) cells. However, whether estrogen regulates MICA/B expression and affects tumor immune escape remains unknown. In this study, we measured the mRNA levels of MICA, MICB and ADAM17in non-small cell lung cancer (NSCLC) cell lines treated with estrogen. Surface expression of MICA/B on LTEP-a2 and A549 was detected using flow cytometry. We demonstrate that both mRNA and secretory protein levels of MICA/B in lung adenocarcinoma cell lines were upregulated by estradiol. Estradiol enhanced the expression of ADAM17, which was associated with the secretion of MICA/B. This secretion of MICA/B downregulated the NKG2D receptor on the surface of NK92 cells and impaired the cytotoxic activity of NK cells. Estradiol enhanced the expression of ADAM17, which was associated with the secretion of MICA/B. Furthermore, a significant correlation between the concentration of estradiol and the expression of MICA was found in tumor tissues of NSCLC patients. Therefore, we conclude that estrogen can regulate the expression and secretion of MICA/B through ADAM17, which helps lung cancer cells escape NKG2D-mediated immune surveillance.     

A new allele of the mouse hairless gene interferes with Hox/LacZ transgene regulation in hair follicle primordia

A new autosomal recessive mouse mutation, causing loss of hair in homozygous mice 2-3 weeks after birth, arose spontaneously in a colony at the National Institute for Medical Research (NIMR), Mill Hill, London in early 1998. Complementation analysis confirmed that this mutation was an allele of the hairless gene (hr). The gene symbol hr(rhbm) (hairless-rhino-bald Mill Hill) was assigned to reflect the source of the colony. Here we show the molecular defect in these mutants, which is a substantial deletion at the 3'-end of the hairless gene. Morphological and immunological analysis of the new hairless mutation was performed at early postnatal stages. In an effort to address the molecular and cellular mechanisms of the hairless phenotype, we analysed developmental stages before the establishment of alopecia. Using a HoxLacZ reporter line of transgenic mice, epidermal placode formation was followed in embryos. Homozygous mutant embryos (hr(rhbmh)/hr(rhbmh)), containing the LacZ reporter under the control of a Hoxb4 gene enhancer, display sharp loss of LacZ staining in epidermal cells invaginating to form the embryonic hair follicle placode. In the light of targeted mutagenesis data involving a Hox gene in the hair development, we discuss the potential implication of the hr(rhbmh) locus in cascades of Hox gene regulation during embryogenesis.