MicroRNA-21对瘢痕疙瘩成纤维细胞mTOR信号通路的调控作用研究

目的:探讨MicroRNA(miR)-21对瘢痕疙瘩成纤维细胞哺乳动物雷帕霉素靶蛋白(mTOR)信号通路的调控作用及机制。方法:应用miR-21抑制物(inhibitor)及阴性对照(NC)序列转染人瘢痕疙瘩成纤维细胞后,反转录(RT)-PCR检测miR-21及10号染色体张力缺失蛋白磷酸酶(PTEN)mRNA表达水平;western blot检测m TOR信号通路关键分子PTEN、磷脂酰肌醇3-激酶(PI3K)、蛋白激酶BPKB(p-Akt,又称Akt)及p-mTOR蛋白的表达。生物信息学方法预测miR-21与PTEN mRNA 3′-UTR结合位点,并用双萤光素酶报告基因验证miR-21对PTEN m RNA的靶向作用;四甲基偶氮唑蓝(MTT)法检测瘢痕疙瘩成纤维细胞增殖。结果:miR-21能够靶向调控PTEN m RNA表达,抑制miR-21表达可导致PTEN的m RNA和蛋白表达增加,进而抑制p-Akt及p-mTOR蛋白的表达,从而抑制瘢痕疙瘩成纤维细胞增殖。结论:miR-21可通过靶基因PTEN调控瘢痕疙瘩成纤维细胞mTOR信号通路关键分子p-Akt和p-mTOR的表达。     

五倍子瘢痕膏对瘢痕疙瘩miR-21/mTOR信号通路相关分子表达的影响

目的观察五倍子瘢痕膏对瘢痕疙瘩miR-21/mTOR信号通路关键分子miR-21、磷脂酰肌醇3-激酶(PI3K)、10号染色体张力缺失蛋白磷酸酶(PTEN)、蛋白激酶B(Akt)、哺乳动物雷帕霉素靶蛋白(mTOR)表达的影响。方法将36只裸鼠瘢痕疙瘩模型随机分成治疗组和对照组,每组18只。治疗组涂抹五倍子瘢痕膏,对照组仅涂抹制作五倍子瘢痕膏的基质,3次/d,连续30 d。然后分别应用逆转录聚合酶链反应(RT-PCR)和免疫组化技术检测治疗组、对照组及正常皮肤组中miR-21和PI3K、PTEN、Akt、mTOR的表达。结果RT-PCR检测结果显示,治疗组和正常皮肤组miR-21相对表达量差异无统计学意义(P>0.05,t=1.24),但二者与对照组相比均明显降低,差异有统计学意义(P<0.05,t=2.76、2.81);免疫组化检测结果显示,PI3K、Akt、mTOR在对照组中高表达,而在治疗组和正常皮肤组中低表达;PTEN在对照组中低表达,而在治疗组和正常皮肤组中高表达。结论五倍子瘢痕膏抑制瘢痕疙瘩成纤维细胞增殖的机制可能与其通过抑制miR-21表达而上调PTEN表达,进而下调mTOR信号通路中PI3K、Akt、mTOR表达有关。其中PTEN是负反馈调节因子;下游的核糖体蛋白S6激酶(S6K)、真核细胞翻译起始因子4E结合蛋白(4EBP),二者均是蛋白翻译的关键调节因子。     

基于PI3KAkt-Bcl-2通路探讨TSG-6对人瘢痕疙瘩凋亡机制的影响

目的基于PI3KAkt-Bcl-2通路探讨肿瘤坏死因子-α刺激基因(TSG)-6对人瘢痕疙瘩凋亡机制的影响。方法以本院2017年8月—2018年8月通过手术治疗的56例瘢痕疙瘩患者为对象,收集其手术标本,对TSG-6过度表达细胞株(过度表达组)、TSG-6干扰细胞株(干扰组)、TSG-6过度表达对照细胞株(过度表达对照组)、TSG-6干扰对照细胞株(干扰对照组)进行构建,测定以上4组及瘢痕疙瘩成纤维细胞中PI3K、Akt、Bcl-2表达情况。结果过度表达组细胞凋亡率是36.67%,分别较过度表达干扰组的16.67%、干扰组的13.33%、干扰对照组的6.67%、瘢痕疙瘩成纤维细胞的10.00%高,差异有统计学意义(P0.05);过度表达组细胞增殖速度较瘢痕疙瘩成纤维细胞慢,干扰组细胞增殖效应显著较其余组别高,差异有统计学意义(P0.05),过度表达对照组、干扰对照组、瘢痕疙瘩成纤维细胞凋亡对比则差异无统计学意义(P0.05);过度表达组PI3K、Akt、Bcl-2基因mRNA与蛋白表达均显著较干扰组、过度表达对照组、干扰对照组、瘢痕疙瘩成纤维细胞低,干扰组PI3K、Akt、Bcl-2基因mRNA与蛋白表达均较过度表达组、过度表达对照组、干扰对照组、瘢痕疙瘩成纤维细胞高,差异有统计学意义(P0.05),过度表达对照组、干扰对照组、瘢痕疙瘩成纤维细胞对比则差异无统计学意义(P0.05)。结论 TSG-6过度表达可抑制瘢痕疙瘩成纤维细胞中PI3K、Akt、Bcl-2表达,表明TSG-6可对PI3KAkt-Bcl-2通路产生负向调控作用,促进瘢痕疙瘩成纤维细胞凋亡,进而达到抑制瘢痕疙瘩增生的效果。     

4-HPR对瘢痕疙瘩成纤维细胞Procollagen Ⅰ、MMP-1及信号通路PI3K/Akt的影响

目的探讨4-羟苯基维胺(4-hydroxyphenyl-retinamide,4-HPR)对瘢痕疙瘩成纤维细胞的作用及PI3K/Akt信号转导通路的影响。方法通过免疫印迹方法检测人瘢痕疙瘩成纤维细胞中,4-HPR对Ⅰ型前胶原(type I pro-collagen,ProcollagenⅠ)和基质金属蛋白酶-1(matrix metallo-protein-1,MMP-1)蛋白表达水平,观察4-HPR联合TGF-β1、PD98059、SP600125、SB203580及LY294002对瘢痕疙瘩成纤维细胞中相关蛋白表达的影响。结果瘢痕疙瘩成纤维细胞中,4-HPR使ProcollagenⅠ蛋白表达水平明显减少,MMP-1蛋白表达水平明显增加,并且具有4-HPR浓度依赖性(P0.01)。在瘢痕疙瘩成纤维细胞中,4-HPR+TGF-β1组中ProcollagenⅠ蛋白表达水平较TGF-β1组明显降低(P0.01),但P-Smad2和P-Smad3蛋白表达均无显著改变(P0.05)。LY294002组中ProcollagenⅠ蛋白水平与对照组相比显著降低,MMP-1显著升高(P0.01)。但PD98059、SB203580及SP600125组中ProcollagenⅠ和MMP-1蛋白水平与对照组相比未发生明显变化(P0.05),且4-HPR可有效抑制P-Akt蛋白表达水平(P0.01)。结论人瘢痕疙瘩成纤维细胞中,4-HPR可以抑制Ⅰ型前胶原蛋白的表达、上调MMP-1的表达,而这种调控作用可能与PI3K/Akt信号传导通路被削弱有关。     

卵巢癌组织中PLOD2的表达及其在缺氧条件下通过PI3K/Akt通路对卵巢癌细胞作用的研究

目的探究前胶原-赖氨酸,2-氧戊二酸5-双加氧酶2(PLOD2)对卵巢癌细胞的作用及其可能的作用机制。方法收集2017年8月至2019年1月在海南医学院附属海南医院行手术治疗的33例卵巢癌患者的癌组织标本作为卵巢癌组,另收集同期的行良性卵巢囊肿切除33例患者的正常卵巢组织作为正常组。采用实时荧光定量聚合酶链反应(RT-PCR)?免疫组化(IHC)和Western Blot检测组织中PLOD2的表达;将卵巢癌细胞SK-OV-3进行缺氧处理,采用RT-PCR检测PLOD2 mRNA的表达;采用Western Blot检测PLOD2?p-PI3 K?PI3 K?p-Akt和Akt的蛋白表达;采用CCK-8实验检测细胞活力;采用5-乙炔基-2′-脱氧尿苷(EdU)实验检测细胞增殖;采用Transwell实验检测细胞迁移和侵袭。结果与正常组比较,卵巢癌组卵巢组织中PLOD2 mRNA和蛋白表达?IHC评分明显升高(P<0.05)。与缺氧0h的细胞比较,缺氧24h和缺氧48h细胞中PLOD2 mRNA表达和蛋白表达明显升高(P<0.05);与缺氧24h的细胞比较,缺氧48h细胞中PLOD2 mRNA表达和蛋白表达明显升高(P<0.05)。在缺氧条件下,与si-NC组相比,si-PLOD2组细胞在24h?48h和72h的细胞活力?EdU+细胞数?迁移细胞数以及侵袭细胞数明显降低(P<0.05),PLOD2?p-PI3 K/PI3 K和p-Akt/Akt表达明显降低(P<0.05)。结论卵巢癌组织中PLOD2高表达,在缺氧条件下,PLOD2可能通过激活PI3 K/Akt通路促进卵巢癌细胞增殖?迁移和侵袭。     

PI3K和磷酸化Akt在尖锐湿疣皮损中的表达

目的:检测PI3K/Akt信号转导通路中PI3K和磷酸化Akt在尖锐湿疣皮损中的表达.方法:采用免疫组化和蛋白印迹法检测30例尖锐湿疣皮损及15例正常对照者皮肤活检组织中PI3K和磷酸化Akt的表达,并利用计算机图像采集与分析系统对免疫组化结果进行平均吸光度(A值)测定和对免疫印迹测定结果进行灰度扫描.结果:尖锐湿疣皮损中PI3K和磷酸化Akt的表达明显高于正常皮肤.蛋白印迹结果与免疫组化检测一致(两组比较,均P＜ 0.01).结论:PI3K/Akt信号通路异常激活可能参与了尖锐湿疣的发病.     

Akt/mTOR活化抗UVB诱导HaCaT细胞凋亡的研究

目的 探讨Akt/mTOR信号通路活化抗中波紫外线（UVB）诱导的HaCaT细胞凋亡。方法 UVB照射角质形成细胞,Western印迹检测Akt/mTOR通路中相关信号分子的动态水平变化。免疫荧光 Hoechst 33342染色观察HaCaT细胞凋亡率。结果 UVB能活化Akt/mTOR信号通路,并在一定范围内（5 ～ 30 mJ/cm2）成剂量依赖性,在一定范围内（5 ～ 30 min）成时间依赖性。EGFR抑制剂PD 153035、PI3K抑制剂LY 294002和mTOR抑制剂雷帕霉素能显著抑制UVB对Akt/mTOR信号通路的活化作用。UVB照射前加入雷帕霉素、LY 294002预处理,HaCaT细胞凋亡率增加。结论 Akt/mTOR活化抗UVB诱导的HaCaT细胞凋亡。     

干扰NDRG1表达通过调控PI3K/Akt信号通路对皮肤鳞状细胞癌细胞凋亡的影响

目的探讨小干扰RNA(siRNA)干扰N-myc下游调节基因1(NDRG1)基因表达对皮肤鳞状细胞癌A431细胞凋亡及PI3K/AKT信号通路的影响。方法将siRNA-NDRG1干扰质粒转染至人皮肤鳞状细胞癌A431细胞中,采用RT-PCR和Western blot检测A431细胞中NDRG1 mRNA和蛋白表达;采用CCK-8、流式细胞术分别检测A431细胞增殖活性和凋亡率;采用Western blot检测A431细胞中凋亡相关蛋白Caspase3、Bax和Bcl-2以及PI3K/AKT信号通路相关蛋白PI3K、p-PI3K、AKT和p-AKT表达水平。采用100μg/L的PI3K/AKT信号通路特异性激活剂IGF-1与si-NDRG1单独或联合处理A431细胞,流式细胞术和Western blot检测细胞凋亡率以及PI3K、p-PI3K、AKT和p-AKT蛋白表达水平。结果 NDRG1 siRNA干扰可显著抑制A431细胞中NDRG1 mRNA和蛋白表达;干扰NDRG1基因表达可显著抑制A431细胞增殖活性,提高细胞凋亡率,并上调Cleaved-Caspase3和Bax蛋白表达水平,下调Bcl-2、p-PI3K及p-AKT蛋白水平;然而,IGF-1与si-NDRG1联合作用时,IGF-1可抑制NDRG1基因干扰后对A431细胞凋亡的促进作用以及对p-PI3K和p-AKT蛋白的下调作用。结论干扰NDRG1基因表达可通过抑制PI3K/AKT信号通路活化诱导人皮肤鳞状细胞癌细胞凋亡。     

mTORC1信号通路在狼疮鼠体内的表达及意义

目的：检测mTORC1信号通路在系统性红斑狼疮鼠体内的表达,探讨其在系统性红斑狼疮发病中的作用。方法： 研究对象为6只B6.MRL/lpr狼疮小鼠和6只C57正常小鼠。RT-PCR和Western blot检测肾脏组织Akt、mTOR、p70S6K、IL-17 mRNA和蛋白的表达。细胞内染色流式细胞术检测脾脏Th17淋巴细胞亚群比例。结果： 狼疮鼠组Akt、mTOR、p70S6K、IL-17 mRNA、磷酸化蛋白表达水平高于对照组（P<0.05）;狼疮鼠组的Th17细胞占CD4+T细胞的比例高于正常对照组（P<0.05）。结论： mTORC1（Akt-mTOR-p70S6K）信号通路在SLE的发病中起着重要作用。     

人真皮网状层成纤维细胞在瘢痕疙瘩皮损组织中的表达与分布

【摘要】 目的 探讨人真皮乳头层成纤维细胞（Fp）、网状层成纤维细胞（Fr）和肌成纤维细胞（MFB）在瘢痕疙瘩皮损组织中的表达与分布。方法 2019年5 - 12月在武汉大学人民医院皮肤科门诊确诊的15例瘢痕疙瘩患者,男8例,女7例,年龄20 ~ 50岁,取皮损组织,以15例年龄匹配的女性乳房整形术正常皮肤组织为对照。采用双重免疫荧光染色法检测成纤维细胞活化蛋白（FAP）、CD90和α平滑肌肌动蛋白（α-SMA）在瘢痕疙瘩和正常皮肤组织中的分布。从3例正常皮肤和3例瘢痕疙瘩组织中分离成纤维细胞原代培养,采用10 ng/ml 转化生长因子β1（TGF-β1）体外处理两组细胞0 ~ 48 h,观察细胞表型的变化,荧光定量RT-PCR和Western印迹检测FAP、CD90和α-SMA mRNA和蛋白表达。两组间差异比较采用t检验。结果 免疫荧光结果显示,正常皮肤组织中,FAP+/CD90-细胞主要分布在真皮浅层,FAP-/CD90+细胞集中在真皮深层,CD90+细胞几乎不表达α-SMA;瘢痕疙瘩组织深层可见大量FAP+和CD90+细胞,大量CD90+细胞同时表达α-SMA。双重免疫荧光染色显示,正常皮肤成纤维细胞几乎不表达α-SMA,瘢痕疙瘩成纤维细胞表达α-SMA;TGF-β1处理24 h时,正常成纤维细胞和瘢痕疙瘩成纤维细胞α-SMA+细胞荧光强度（21.058 ± 0.709、27.112 ± 0.097）均高于未处理组（11.312 ± 0.636、21.306 ± 0.464）,t值为22.430、13.370,P < 0.05。RT-PCR和Western印迹显示,TGF-β1处理48 h时,瘢痕疙瘩成纤维细胞FAP、CD90、α-SMA mRNA相对表达水平（92.610 ± 3.667、1.366 ± 0.105、3.240 ± 0.141）与蛋白表达水平（0.652 ± 0.073、1.046 ± 0.119、0.946 ± 0.117）均高于处理前（均P < 0.05）。结论 瘢痕疙瘩组织真皮深层的CD90+（Fr）细胞异常增生,提示针对真皮深层异常增殖活跃的FAP-/CD90+（Fr）细胞群进行定向干预可能提高瘢痕疙瘩治疗疗效。     

Inhibition of ANGPT2 activates autophagy during hypertrophic scar formation via PI3K/AKT/mTOR pathway

BackgroundHypertrophic scar (HS), a fibroproliferative disorder caused by aberrant wound healing following skin injuries such as burns, lacerations and surgery, is characterized by invasive proliferation of fibroblasts and excessive extracellular matrix (ECM) accumulation. The dysregulation of autophagy is the pathological basis of HS formation. Previously, angiopoietin-2 (ANGPT2) was found to be overexpressed in HS fibroblasts (HSFs) compared with normal skin fibroblasts. However, whether ANGPT2 participates in the process of HS formation and the potential molecular mechanisms are not clear.ObjectiveThis study is intended to figure out the role of ANGPT2 and ANGPT2-mediated autophagy during the development of HS.MethodsRT-qPCR was used to detect ANGPT2 expression in HS tissues and HSFs. HSFs were transfected with sh-ANGPT2 to knock down ANGPT2 expression and then treated with MHT1485, the mTOR agonist. The effects of sh-ANGPT2 or MHT1485 on the proliferation, migration, autophagy and ECM accumulation of HSFs were evaluated by CCK-8 assay, Transwell assay and western blotting. The expression of PI3K/Akt/mTOR pathway-related molecules (p-PI3K, p-Akt and p-mTOR) was assessed by western blotting.ResultsANGPT2 expression was markedly upregulated in HS tissues and HSFs. ANGPT2 knockdown decreased the expression of p-PI3K, p-Akt and p-mTOR. ANGPT2 knockdown activated autophagy and inhibited the proliferation, migration, and ECM accumulation of HSFs. Additionally, the treatment of MHT1485, the mTOR agonist, on ANGPT2-downregulated HSFs, partially reversed the influence of ANGPT2 knockdown on HSFs.Study limitationsThe study lacks the establishment of more stable in vivo animal models of HS for investigating the effects of ANGPT2 on HS formation in experimental animals.ConclusionsANGPT2 downregulation represses growth, migration, and ECM accumulation of HSFs via autophagy activation by suppressing the PI3K/Akt/mTOR pathway. Our study provides a novel potential therapeutic target for HS.     

Epidermal growth factor-induced matrix metalloproteinase-1 expression is negatively regulated by p38 MAPK in human skin fibroblasts

Background

Many extracellular stimuli, including epidermal growth factor (EGF), are known to induce MMP-1 expression. Recently, several reports have shown that ERK activity plays an important role in EGF-induced MMP-1 expression. However, EGF is also known to activate many signaling pathways in addition to the ERK pathway, but the roles of these pathways during the induction of MMP-1 by EGF are unclear.

Objective

We investigated the role of JNK, p38 MAPK, and PI3K/Akt pathways in EGF-induced MMP-1 expression in human skin fibroblasts. Then, we further explored the inhibitory effect of p38 MAPK pathway on EGF-induced MMP-1 expression and studied the molecular mechanisms involved in the processes.

Methods

Human skin fibroblasts were pretreated with various chemical inhibitors or small interfering RNA (siRNA) at the indicated concentrations and then treated with EGF, TNF-alpha, or IL-1beta for the indicated times. Protein and mRNA levels of various target molecules were assessed by Western blotting and quantitative real-time PCR, respectively.

Results

We found that EGF-induced MMP-1 expression was positively regulated by JNK as well as ERK but negatively regulated by p38 MAPK in human skin fibroblasts. On the other hand, the PI3K/Akt pathway did not significantly affect MMP-1 induction by EGF. Then we found that the inhibition of p38 MAPK pathway specifically increased the MMP-1 expression stimulated by EGF but not by TNF-alpha or IL-1beta, indicating that the effect of p38 MAPK on MMP-1 expression may be stimulus-type specific in human skin fibroblasts. In addition, the inhibitory effect of p38 MAPK on EGF-induced MMP-1 expression was shown to be mainly mediated by p38-alpha MAPK. Our further studies showed that the inhibition of p38 MAPK but not PI3K specifically increased EGF-induced ERK and JNK activations, and that the augmentation of EGF-induced MMP-1 expression by p38 MAPK inhibition was significantly attenuated by inhibiting the activities of ERK and/or JNK.

Conclusions

Our results indicate that EGF-induced MMP-1 expression is differentially regulated by the JNK, p38 MAPK, and PI3K/Akt pathways, and suggest that p38 MAPK negatively regulates EGF-induced MMP-1 expression by suppressing the activations of ERK and JNK.     

麦冬皂苷B通过抑制PI3K/Akt/mTOR通路诱导人黑色素瘤A375细胞凋亡

目的探讨麦冬皂苷B对人黑色素瘤(Melanoma)A375细胞增殖,凋亡和细胞周期的影响以及相关机制。方法麦冬皂苷B处理A375细胞后,采用CCK-8法检测细胞活力;流式细胞仪检测A375细胞周期变化及细胞凋亡水平;Hoechst33258荧光染色法观察细胞凋亡形态;免疫印迹法检测麦冬皂苷B对A375细胞PI3K,p-PI3K,AKT,p-AKT蛋白以及通路下游凋亡相关蛋白Bcl-2,Bax,Cleaved-caspase3表达的影响。结果麦冬皂苷B能抑制A375细胞增殖活力及PI3K/Akt/mTOR通路的活化;麦冬皂苷B促进了A375细胞内Bax和Cleaved-caspase 3的表达,抑制Bcl-2表达,诱导人黑色素瘤细胞发生凋亡;麦冬皂苷B阻滞了A375细胞细胞周期,G0/G1期细胞比例明显升高;PI3K/Akt/mTOR通路活化剂IGF-1处理A375细胞后抑制了麦冬皂苷B的上述作用。结论麦冬皂苷B能抑制A375细胞的增殖,诱导细胞发生凋亡,阻滞细胞周期于G0/G1期。     

丹参酮ⅡA体外促进黑素瘤A375细胞自噬及信号通路的实验研究

目的：探讨丹参酮ⅡA体外对黑素瘤细胞A375细胞自噬的影响及其信号通路研究。方法0.5、1、2、4 mg/L丹参酮ⅡA作用黑素瘤A375细胞24、48、72 h后，噻唑蓝（MTT）比色法检测A375细胞的增殖活性。1、2、4 mg/L丹参酮ⅡA作用黑素瘤A375细胞48 h，采用流式细胞仪检测细胞自噬小体的数量，Western印迹检测自噬相关蛋白Beclin?1和微管相关蛋白1轻链3（LC3）?Ⅱ蛋白及磷酸肌醇3激酶（PI3K）、蛋白激酶B（Akt）、雷帕霉素靶蛋白（mTOR）、p70S6激酶1（p70S6K1）蛋白的表达水平。结果 MTT分析显示，0.5、1、2和4 mg/L丹参酮ⅡA分别作用黑素瘤A375细胞24、48、72 h，均能抑制A375细胞的增殖能力，且抑制作用呈剂量和时间依赖性（F=2564.12、1235.25，均P<0.05）。流式细胞仪显示，1、2和4 mg/L丹参酮ⅡA作用A375细胞48 h后，细胞内自噬小体比例分别为6.91%±0.35%、13.11%±0.73%、25.51%±0.83%，均明显高于对照组（0.41%±0.02%），各组间差异有统计学意义（均P<0.05）。Western印迹显示，1、2和4 mg/L丹参酮ⅡA作用A375细胞48 h后，细胞自噬相关蛋白Beclin?1和LC3?Ⅱ表达水平随丹参酮ⅡA浓度增加而升高，各丹参酮ⅡA组间差异有统计学意义，且高于对照组（均P<0.05）。而PI3K?Akt?mTOR?p70S6K1信号通路中PI3K、p?Akt、p?mTOR和p?p70S6K1蛋白表达随丹参酮ⅡA浓度增加而下降，各丹参酮ⅡA组间差异有统计学意义，且低于对照组（均P<0.05）。结论丹参酮ⅡA可通过抑制P13K?Akt?mTOR?p70S6K1信号通路，促进黑素瘤细胞发生自噬。     

p62通过调控PI3K/AKT通路促进黑素瘤增殖

目的探讨p62促进黑素瘤A375细胞生长增殖的作用及具体机制。方法取生长状态良好的黑素瘤A375细胞,采用干扰p62表达的siRNA片段转染A375细胞;EDU着色法检测干扰组和对照组的细胞分裂情况;采用Western blot检测干扰组和对照组PI3K/AKT/mTOR及下游因子的表达情况。结果干扰组的EDU着色数目较对照组明显减少;p62干扰后PI3K/AKT/mTOR及下游因子的表达明显受抑制。结论p62可能通过调控PI3K/AKT通路发挥促进黑素瘤增殖的作用。     

Anti-ageing effects of alpha-naphthoflavone on normal and UVB-irradiated human skin fibroblasts

Ageing is a complex and multifactorial process resulting in several functional and aesthetic changes to the skin. We found that α-Naphthoflavone (α-NF) concentration-dependently induced pro-collagen type I protein expression and inhibited MMP-1 protein expression, in both normal and UVB-irradiated cells. SB431542 and SIS3 - inhibitors of TGF-β and Smad3, respectively - significantly alleviate α-NF-caused response of MMP-1 and pro-collagen. LY294002 (PI3K inhibitor) can reverse α-NF-induced ERK, Akt, Smad-3 activation, pro-collagen synthesis and α-NF-suppressed AP-1 activation. PD (ERK inhibitor) was not involved in pro-collagen generation and MMP-1 inhibition. We concluded that α-NF promotes pro-collagen production and inhibits MMP-1 expression via the activation of a PI3K/Akt/Smad-3 pathway in normal and UVB-irradiated human skin fibroblasts, while TGF-β may play an important role in transducing this pathway. These results suggest that α-NF, a natural plant product, has the potential to become a novel anti-ageing skin application.