壳聚糖修饰丝素蛋白与人脂肪间充质干细胞体外构建组织工程脂肪

背景：在保留丝素蛋白原有优点的基础上,采用带正电荷的水溶性壳聚糖对其表面进行修饰,可改善细胞在支架材料上的黏附性。目的：验证壳聚糖表面修饰丝素蛋白支架材料与人脂肪间充质干细胞的生物相容性及两者体外构建组织工程脂肪的可行性。方法：将第3代人脂肪间充质干细胞悬液以1×107 L-1浓度接种于壳聚糖表面修饰丝素蛋白支架材料上作为实验组,以单纯的细胞悬液为对照组,MTT法检测细胞在支架材料上的黏附和增殖能力。将第3代人脂肪间充质干细胞悬液以1×109 L-1浓度接种于壳聚糖表面修饰丝素蛋白支架材料上,分别进行成脂诱导培养与高糖培养基常规培养,14 d后行细胞-支架复合物油红O染色与RT-PCR检测。结果与结论：人脂肪间充质干细胞在壳聚糖表面修饰丝素蛋白支架材料上黏附、增殖良好。成脂诱导14 d后,油红 O 染色显示壳聚糖修饰丝素蛋白支架材料上有大量脂肪细胞生成,且过氧化物酶增殖物活化受体γ2基因表达阳性。结果表明壳聚糖表面修饰丝素蛋白支架材料具有良好的体外生物相容性,与人脂肪间充质干细胞共培养可被成功诱导为成熟脂肪细胞。     

蛋白酶体抑制剂对多发性骨髓瘤患者骨髓间充质干细胞迁移能力及其肝细胞生长因子表达的影响

本研究探讨蛋白酶体抑制剂硼替佐米对多发性骨髓瘤(MM)患者骨髓间充质干细胞(MSC)迁移能力及其肝细胞生长因子(HGF)基因表达水平的影响。应用Transwell模型观察MM患者骨髓MSC经2.5 nmol/L硼替佐米处理前后的体外迁移能力,实时定量PCR检测MSC的HGF mRNA的表达水平。结果表明,经2.5 nmol/L的硼替佐米作用48小时后,MSC的迁移能力明显低于对照组,并且HGF mRNA在MSC的表达与对照组相比也明显降低,两者结果均具有统计学意义(p<0.05)。结论:硼替佐米可抑制MM患者骨髓MSC的迁移,同时可下调其趋化相关因子HGF的表达。     

Mesenchymal stem cells: biological properties and clinical applications

Importance of the field: In the last decade, knowledge of mesenchymal stem cells (MSCs) has evolved rapidly; their immunomodulatory properties and paracrine interactions with specific cell types in damaged tissues and promising results in some clinical applications have made these cells an attractive option for the treatment of certain diseases.

Areas covered in this review: We present some relevant methodological issues and biological properties of MSCs, as well as clinical applications of MSC therapies with particular emphasis in the treatment of graft versus host disease (GVHD), complex perianal fistula and refractory metastatic neuroblastoma. Other topical aspects relevant to the application of cellular therapies such as biosafety studies and cellular production of MSCs are also discussed in this review.

What the reader will gain: The growing optimism regarding MSCs research is based on the promising results obtained in in vitro and in vivo studies. The rapid translational research with MSCs necessitated standardization of methodology and terminology and greater focus on other aspects such as biosafety and cellular production, especially for clinical use of MSCs.

Take home message: Much has been learned about the biology and applications of MSCs and much remains to be learned.     

Transforming growth factor‐beta1 inhibits tissue engineering cartilage absorption via inducing the generation of regulatory T cells

The objective of the present study was to explore the mechanisms of transforming growth factor (TGF)‐β1 inhibiting the absorption of tissue engineering cartilage. We transfected TGF‐β1 gene into bone marrow mesenchymal stem cells (BMMSCs) and co‐cultured with interferon (IFN)‐γ and tumour necrosis factor (TNF)‐α and CD4⁺CD25^? T lymphocytes. We then characterized the morphological changes, apoptosis and characterization of chondrogenic‐committed cells from TGF‐β1⁺BMMSCs and explored their mechanisms. Results showed that BMMSCs apoptosis and tissue engineering cartilage absorption in the group with added IFN‐γ and TNF‐α were greater than in the control group. In contrast, there was little BMMSC apoptosis and absorption by tissue engineering cartilage in the group with added CD4⁺CD25^? T lymphocytes; Foxp3⁺T cells and CD25⁺CD39⁺ T cells were found. In contrast, no type II collagen or Foxp3⁺T cells or CD25⁺CD39⁺ T cells was found in the TGF‐β1^–BMMSC group. The data suggest that IFN‐γ and TNF‐α induced BMMSCs apoptosis and absorption of tissue engineering cartilage, but the newborn regulatory T (Treg) cells inhibited the function of IFN‐γ and TNF‐α and protected BMMSCs and tissue engineering cartilage. TGF‐β1not only played a cartilage inductive role, but also inhibited the absorption of tissue engineering cartilage. The pathway proposed in our study may simulate the actual reaction procedure after implantation of BMMSCs and tissue engineering cartilage in vivo. Copyright © 2013 John Wiley & Sons, Ltd.     

Mathematical modelling of glycosaminoglycan production by stem cell aggregates incorporated with growth factor‐releasing polymer microspheres

Systems composed of high density cells incorporated with growth factor‐releasing polymer microspheres have recently been shown to promote chondrogenic differentiation and cartilage formation. Within these systems, the effects of spatial and temporal patterning of growth factor release on hyaline cartilage‐specific extracellular matrix production have been examined. However, at present, it is unclear which microsphere densities and growth factor delivery profiles are optimal for inducing human mesenchymal stem cell differentiation and glycosaminoglycan production. A mathematical model to describe glycosaminoglycan production as a function of initial microsphere loading and microsphere degradation rate over a period of 3 weeks is presented. Based on predictions generated by this model, it may be feasible to design a bioactive microsphere system with specific spatiotemporal growth factor presentation characteristics to promote glycosaminoglycan production at controllable rates. Copyright © 2014 John Wiley & Sons, Ltd.     

Enhancement of wound closure by modifying dual release patterns of stromal‐derived cell factor‐1 and a macrophage recruitment agent from gelatin hydrogels

The objective of the present study is to evaluate the effects of the release patterns of stromal derived factor (SDF)‐1 and sphingosine‐1 phosphate agonist (SEW2871), used as MSC and macrophage recruitment agents, on the wound closure of diabetic mouse skin defects. To achieve different release patterns, hydrogels were prepared using two types of gelatin with isoelectric points (IEP) of 5 and 9, into which SDF‐1 and SEW2871 were then incorporated in various combinations. When the hydrogels incorporating SDF‐1 and SEW2871 were applied into wound defects of diabetic mice, the number of MSCs and macrophages recruited to the defects and the levels of pro‐ and anti‐ inflammatory cytokines were found to be dependent on the release profiles of SDF‐1 and SEW2871. Of particular interest was the case of a rapid release of SDF‐1 combined with a controlled release of SEW2871. This resulted in a higher number of M2 macrophages and gene expression levels of anti‐inflammatory cytokines 3 days after implantation and faster wound closure than when pairing the controlled release of SDF‐1 with a rapid release of SEW2871. Therefore, the present study demonstrates that different release patterns of SDF‐1 and SEW2871 can enhance the in vivo recruitment of MSCs and macrophages, and can promote skin wound closure through the modulation of inflammation. Copyright © 2016 John Wiley & Sons, Ltd.     

联合应用骨髓间充质干细胞与促肝细胞生长素治疗大鼠急性肝衰竭

目的 评价骨髓间充质干细胞(MSCs)和促肝细胞生长素(pHGF)联合治疗大鼠急性肝衰竭(ALF)的可行性.方法 将ALF造模成功的37只SD大鼠分为4组:CC14组(A组,9只),CCl4/MSCs(B组,9只),CC14/pHGF组(C组,9只)和CC14/pHGF+ MSCs组(D组,10只).用携带hrGFP基因的慢病毒感染MSCs(hrGFP-MSCs),并以hrGFP示踪.对C、D组大鼠给予CCl4,同时腹腔注射pHGF;B组和D组造模12h后肝内注射hrGFP-MSCs悬液.对各组大鼠分别在造模后24 h、72 h、7天检测血清丙氨酸转氨酶(ALT)水平,造模后72 h检测血清IL-6、IL-10、TNF-α炎症因子水平,造模后24 h取肝组织行HE染色,造模72 h行PCNA免疫组化染色检测肝细胞增殖情况.造模后72 h后取注射部位肝组织行冰冻切片观察移植hrGFP-MSCs肝内分布情况,对非注射部位肝组织进行实时荧光定量RT-PCR检测hrGFP基因含量.结果 联合治疗后,ALF大鼠外周血ALT水平降低,IL 6、IL-10、TNF-α炎症因子水平下调,肝脏病理组织学损害减轻,肝细胞增殖率增高.造模后72 h,B组与D组注射部位肝组织内可见移植的hrGFP-MSCs,非注射部位肝组织未见hrGFP荧光阳性细胞,但用实时荧光定量RT-PCR技术可在非注射部位肝组织内检测到hrGFP基因,且D组含量高于B组.结论 pHGF与MSCs联合治疗大鼠ALF的疗效优于MSCs或pHGF单独治疗,可能与pHGF促使其肝内定植MSCs增多有关.     

细胞因子修饰的间充质干细胞

背景：将细胞治疗与基因治疗相结合,通过不同的细胞因子对间充质干细胞的修饰,不但可以赋予其新的能力,更能增强其本身的功能。但是在西北高原的低氧环境下,间充质干细胞的功能发挥就会受到一定的限制。目的：文章综述了间充质干细胞近年来的研究进展,在与细胞因子联合应用后功能上的扩展,并寻找新的手段使其在高原低氧环境下充分发挥功能。方法：应用计算机检索CNKI数据库和PUBMED数据库中关于间充质干细胞的文章,以＂间充质干细胞;低氧诱导因子;肝细胞生长因子＂或＂mesenchymal stem cells;hypoxia inducible factor;hepatocyte growth factor＂为检索词进行检索。检索文献总量为71篇,选择文章内容与间充质干细胞及其临床应用有关方面的文章,同一领域文献则选择近期发表或发表在权威杂志文章。结果与结论：最终纳入35篇符合标准的文献。通过应用细胞因子的转染,将细胞因子的功能与间充质干细胞相结合,使得间充质干细胞的功能更全面,在高原低氧的恶劣环境下,依然能够有效的发挥临床效用,满足其临床上的治疗需求。     

Potential benefits of allogeneic bone marrow mesenchymal stem cells for wound healing

Introduction: It is becoming increasingly evident that select adult stem cells have the capacity to participate in repair and regeneration of damaged and/or diseased tissues. Mesenchymal stem cells have been among the most studied adult stem cells for the treatment of a variety of conditions, including wound healing.

Areas covered: Mesenchymal stem cell features potentially beneficial to cutaneous wound healing applications are reviewed.

Expert opinion: Given their potential for in vitro expansion and immune modulatory effects, both autologous and allogeneic mesenchymal stem cells appear to be well suited as wound healing therapies. Allogeneic mesenchymal stem cells derived from young healthy donors could have particular advantage over autologous sources where age and systemic disease can be significant factors.     

A collagen cardiac patch incorporating alginate microparticles permits the controlled release of hepatocyte growth factor and insulin‐like growth factor‐1 to enhance cardiac stem cell migration and proliferation

Cardiac stem cells (CSCs) represent a logical cell type to exploit as a regenerative treatment option for tissue damage accrued as a result of a myocardial infarction. However, the isolation and expansion of CSCs prior to cell transplantation is time consuming, costly and invasive, and the reliability of cell expansion may also prove to be a major obstacle in the clinical application of CSC‐based transplantation therapy after a myocardial infarction. In order to overcome this, we propose the incorporation of growth factor‐eluting alginate microparticles into collagen‐based scaffolds as an implantable biomaterial to promote the recruitment and expansion of CSCs in the myocardium. In order to obtain scaffolds able to enhance the motogenic and proliferative potential of CSCs, the aim of this work was to achieve a sustained delivery of both hepatocyte growth factor and insulin‐like growth factor‐1. Both proteins were initially encapsulated in alginate microparticles by spray drying and subsequently incorporated into a collagen scaffold. Microparticles were seen to homogeneously distribute through the interconnected scaffold pore structure. The resulting scaffolds were capable of extending the release of both proteins up to 15 days, a three‐fold increase over non‐encapsulated proteins embedded in the scaffolds. In vitro assays with isolated CSCs demonstrated that the sustained release of both bioactive proteins resulted in an increased motogenic and proliferative effect. As presently practiced, the isolation and expansion of CSCs for autologous cell transplantation is slow, expensive and difficult to attain. Thus, there is a need for strategies to specifically activate in situ the intrinsic cardiac regenerative potential represented by the CSCs using combinations of growth factors obviating the need for cell transplantation. By favouring the natural regenerative capability of CSCs, it is hypothesized that the cardiac patch presented here will result in positive therapeutic outcomes in MI and heart failure patients in the future. Copyright © 2016 John Wiley & Sons, Ltd.     

骨髓间充质干细胞转化为肝样细胞的体外实验研究

目的评价骨髓间充质干细胞（BMSCs）向肝样细胞诱导的可行性。方法2008年1月-2009年1月,以肝细胞生长因子（HGF）20ng/mL,成纤维细胞生长因子4（FGF-4）10ng/mL为诱导剂,从细胞形态变化,并通过RT-PCR、免疫组化方法分别对诱导第7、14、21及28天的细胞进行白蛋白（ALB）、甲胎蛋白（AFP）、细胞角蛋白18（CK18）等检测。人L-02肝细胞及未诱导的BMSCs分别为阳性和阴性对照。结果BMSCs诱导7d出现类圆形或多角形细胞,并出现铺路石样结构;诱导14d细胞呈现典型的铺路石状;诱导21d,同前;诱导28d,细胞排列紊乱,局部细胞的形态不规则、细胞边界不清。BMSCs诱导第7、14、21天ALB、CK18、AFP等mRNA表达阳性;未诱导BMSCs均为阴性;肝细胞ALB、CK18、AFP等mRNA表达均阳性。免疫细胞化学检测结果同RT-PCR。结论以HGF及FGF-4为主的诱导体系可有效诱导BMSCs向肝样细胞转化,BMSCs可以作为一种新的肝细胞来源。     

Application of marrow mesenchymal stem cell‐derived extracellular matrix in peripheral nerve tissue engineering

To advance molecular and cellular therapy into the clinic for peripheral nerve injury, modification of neural scaffolds with the extracellular matrix (ECM) of peripheral nerves has been established as a promising alternative to direct inclusion of support cells and/or growth factors within a neural scaffold, while cell‐derived ECM proves to be superior to tissue‐derived ECM in the modification of neural scaffolds. Based on the fact that bone marrow mesenchymal stem cells (BMSCs), just like Schwann cells, are adopted as support cells within a neural scaffold, in this study we used BMSCs as parent cells to generate ECM for application in peripheral nerve tissue engineering. A chitosan nerve guidance conduit (NGC) and silk fibroin filamentous fillers were respectively prepared for co‐culture with purified BMSCs, followed by decellularization to stimulate ECM deposition. The ECM‐modified NGC and lumen fillers were then assembled into a chitosan–silk fibroin‐based, BMSC‐derived, ECM‐modified neural scaffold, which was implanted into rats to bridge a 10 mm‐long sciatic nerve gap. Histological and functional assessments after implantation showed that regenerative outcomes achieved by our engineered neural scaffold were better than those achieved by a plain chitosan–silk fibroin scaffold, and suggested the benefits of BMSC‐derived ECM for peripheral nerve repair. Copyright © 2016 John Wiley & Sons, Ltd.     

骨髓间充质干细胞参与A549肺腺癌的组织修复

背景：肿瘤被认为是一种特殊的不愈合创伤,骨髓间充质干细胞通过向肿瘤组织归巢和向间质成分分化,参与肿瘤间质重构,从而改变肿瘤微环境,影响肿瘤的生长和转移。目的：在A549肺癌荷瘤小鼠模型上证实骨髓间充质干细胞参与其损伤修复,探讨骨髓间充质干细胞参与肿瘤组织修复的机制。方法：体外分离、培养人骨髓间充质干细胞,使用流式细胞术鉴定,制造A549肺癌荷瘤小鼠模型。实验组采用瘤周注射人骨髓间充质干细胞,对照组注射等量PBS,对比观察动物生活情况,肿瘤生长大小。4周后取材,苏木精-伊红染色对比观察肿瘤组织,Masson染色对比胶原纤维含量,RT-PCR检测两组α平滑肌收缩蛋白的表达,免疫组织化学检测两组成纤维细胞特异蛋白、成纤维细胞活化蛋白的表达情况,反映两组肿瘤组织的间质纤维的程度。免疫组织化学方法对比两组中血管内皮生长因子、肝细胞生长因子、白细胞介素6、肌糖蛋白C的表达高低。结果与结论：骨髓间充质干细胞促进荷瘤小鼠肿瘤的生长,实验组肿瘤组织生长速度明显快于对照组（P〈0.05）。RT-PCR检测α平滑肌收缩蛋白的表达：与对照组比较,实验组α平滑肌收缩蛋白mRNA的表达水平显著升高。免疫组织化学方法检测实验组肿瘤组织中TAFs标志物：成纤维细胞特异蛋白、成纤维细胞活化蛋白的表达,IHC检测血管内皮生长因子、肝细胞生长因子、白细胞介素6、肌糖蛋白C的表达明显高于对照组,差异有显著性意义（P〈0.05）。说明骨髓间充质干细胞在肿瘤微环境中向成纤维细胞方向分化,参与肿瘤间质的形成和构建,分泌血管内皮生长因子、肝细胞生长因子、白细胞介素6、肌糖蛋白C等促进肿瘤的生长修复。     

人胎盘间充质干细胞促进血管生成

背景：构建组织工程化骨组织的同时,促进种子细胞与材料复合物内血液供应的重建成为研究的关键。胎盘间充质干细胞可以作为骨组织工程研究的种子细胞,研究其分化为血管内皮细胞以及促进血管生成有着重要意义。目的：观察胎盘间充质干细胞在体外分化为血管内皮细胞以及体内促血管生成作用。方法：分离培养人胎盘间充质干细胞,鉴定其表面抗原,经血管内皮生长因子和人碱性成纤维细胞生长因子联合体外诱导胎盘来源间充质干细胞向血管内皮细胞定向分化,诱导后细胞通过内皮细胞标志物KDR、v-WF染色鉴定。8只新西兰大白兔制成桡骨中段1．5cm长的骨缺损模型,分别植入人胎盘间充质干细胞,丝素蛋白／羟基磷灰石和丝素蛋白,羟基磷灰石进行对照。植入后4,12周分别行大体观察、组织学观察和X射线观察,比较骨缺损修复以及血管生成情况。结果与结论：胎盘间充质干细胞的诱导分化形态明显改变,胞体逐步回缩,立体感增强,内皮细胞标志物KDR、v-WF染色结果阳性。胎盘来源间充质干细胞与丝素蛋白,羟基磷灰石材料复合培养植入后,4周时新骨已开始形成,12周时有部分新生骨组织形成板层骨,骨小梁形成,内可见新生血管形成,而对照组支架材料降解较慢,未见新生血管。说明胎盘来源间充质干细胞体外可以分化为血管内皮细胞,与丝素蛋白,羟基磷灰石材料联合移植能够促进移植物内血管生成,较好的修复骨缺损。     

Bioglass enhanced wound healing ability of urine‐derived stem cells through promoting paracrine effects between stem cells and recipient cells

In cell therapy, tissue regeneration ability of stem cells relies on the paracrine effects between stem cells and recipient cells. Our recent studies demonstrated that, in tissue engineering, bioactive silicates could stimulate paracrine effects between stem cells and recipient cells, which enhanced tissue generation. Therefore, we proposed that, in cell therapy, it may be an effective method to improve tissue regeneration ability of stem cells through activating the paracrine effects between stem cells and recipient cells with bioactive silicates. As urine‐derived stem cells (USCs) have been injected for wound healing and bioglass (BG) have shown bioactivity for various types of stem cells, in this study, we activated USCs with effective BG ionic products. Then the conditioned medium of BG‐activated USCs were used to culture endothelial cells and fibroblasts as well as co‐cultures of endothelial cells and fibroblasts. Results showed that growth factor expression in BG‐activated USCs was upregulated. In addition, paracrine effects between USCs and recipient cells in wound healing were stimulated, which resulted in enhanced capillary‐like network formation of endothelial cells and matrix protein production as well as myofibroblast differentiation of fibroblasts. Finally, the BG‐activated USCs were applied on full‐thickness excisional wounds. Results confirmed that BG‐activated USCs had better wound healing ability through improving angiogenesis and collagen deposition in wound sites as compared with USCs without any treatment. Taken together, BG can be used to promote wound healing ability of USCs by enhancing paracrine effects between USCs and recipient cells.     

Therapeutic effects of a recombinant human collagen peptide bioscaffold with human adipose‐derived stem cells on impaired wound healing after radiotherapy

Chronic changes following radiotherapy include alterations in tissue‐resident stem cells and vasculatures, which can lead to impaired wound healing. In this study, novel recombinant human collagen peptide (rhCP) scaffolds were evaluated as a biomaterial carrier for cellular regenerative therapy. Human adipose‐derived stem cells (hASCs) were successfully cultured on rhCP scaffolds. By hASC culture on rhCP, microarray assay indicated that expression of genes related to cell proliferation and extracellular matrix production was upregulated. Pathway analyses revealed that signaling pathways related to inflammatory suppression and cell growth promotion were activated as well as signaling pathways consistent with some growth factors including vascular endothelial growth factor, hepatocyte growth factor, and transforming growth factor beta, although gene expression of these growth factors was not upregulated. These findings suggest the rhCP scaffold showed similar biological actions to cytokines regulating cell growth and immunity. In subsequent impaired wound healing experiments using a locally irradiated (20 Gray) mouse, wound treatment with rhCP sponges combined with cultured hASCs and human umbilical vein endothelial cells accelerated wound closure compared with wounds treated with rhCP with hASCs alone, rhCP only, and control (dressing alone), with better healing observed according to this order. These results indicating the therapeutic value of rhCP scaffolds as a topical biomaterial dressing and a biocarrier of stem cells and vascular endothelial cells for regenerating therapies. The combination of rhCP and functional cells was suggested to be a potential tool for revitalizing stem cell‐depleted conditions such as radiation tissue damage.     

MicroRNAs can effectively induce formation of insulin‐producing cells from mesenchymal stem cells

MicroRNAs regulate insulin secretion, pancreatic development and beta cell differentiation. However, the function of microRNAs in the formation of insulin‐producing cells (IPCs) from adult stem cells is poorly understood. We examine the microRNA expression profile in nestin‐positive umbilical cord‐derived mesenchymal stem cells (N‐UCMSCs) and nestin‐positive pancreatic mesenchymal stem cells using a deep sequencing approach. We also selected specific microRNAs for overexpression in N‐UCMSCs and found that miR‐375 and miR‐26a induced IPCs differentiation from N‐UCMSCs by downregulating target genes including mtpn, sox6, bhlhe22 and ccnd1. Small interfering RNAs were also used to knock down these genes in N‐UCMSCs to induce the formation of IPCs. These results suggest that endogenous microRNAs involved in the formation of IPCs from adult stem cells show promise for advancing the development of an effective cell transplant therapy for diabetes. Copyright © 2017 John Wiley & Sons, Ltd.     

Amniotic membrane stimulates cell migration by modulating transforming growth factor‐β signalling

Keratinocyte migration is a mandatory aspect of wound healing. We have previously shown that amniotic membrane (AM) applied to chronic wounds assists healing through a process resulting in the overexpression of c‐Jun at the wound's leading edge. We have also demonstrated that AM modifies the genetic programme induced by transforming growth factor‐ß (TGF‐ß) in chronic wounds. Here we used a scratch assay of mink lung epithelial cells (Mv1Lu) and a spontaneously immortalized human keratinocyte cell line (HaCaT) cells to examine the influence of AM application on the underlying signalling during scratch closure. AM application induced c‐Jun phosphorylation at the leading edge of scratch wounds in a process dependent on MAPK and JNK signalling. Strikingly, when the TGF‐ß‐dependent Smad‐activation inhibitor SB431542 was used together with AM, migration improvement was partially restrained, whereas the addition of TGF‐ß had a synergistic effect on the AM‐induced cell migration. Moreover, antagonizing TGF‐ß with specific antibodies in both cell lines or knocking out TGF‐ß receptors in Mv1Lu cells had similar effects on cell migration as using SB431542. Furthermore, we found that AM was able to attenuate TGF‐ß‐Smad signalling specifically at the migrating edge; AM treatment abated Smad2 and Smad3 nuclear localization in response to TGF‐ß in a process dependent on mitogen‐activated protein kinase kinase 1 (MEK1) activation but independent of EGF receptor or JNK activation. The involvement of Smad signalling on AM effects on HaCaT keratinocytes was further corroborated by overexpression of either Smad2 or Smad3 and the use of Smad phosphorylation‐specific inhibitors, revealing a differential influence on AM‐induced migration for each Smad. Thus, AM TGF‐ß‐Smad signalling abating is essential for optimal cell migration and wound closure.