Background We showed in our previous study that the N-terminal 17-mer peptide of amyloid precursor protein （APP17-mer peptide）,an active peptide segment with trophic and antioxidative effects,protects skin fibroblas...Background We showed in our previous study that the N-terminal 17-mer peptide of amyloid precursor protein （APP17-mer peptide）,an active peptide segment with trophic and antioxidative effects,protects skin fibroblasts against ultraviolet （UV） damage and downregulates matrix metalloproteinase 1 （MMP-1） expression.The aim of the current study was to explore the protective effects of P165,the N-terminal 5-mer peptide analog of amyloid precursor protein that is resistant to enzymolysis,on UVA-induced damage in human dermal fibroblasts （HDFs）.Methods HDFs were cultured in Dulbecco＆#39;s modified Eagle＆#39;s medium without and with P165 （concentrations were 1,10,and 100 μJmol/L）.Then,15 J/cm2 UVA irradiation was used to obtain the UV-irradiated model.Cell proliferation was analyzed using MTT kit.The collagen type Ⅰ and MMP-1 contents in cell lysate were determined by enzyme-linked immunosorbent assay （ELISA）.Fluorometric assays were performed to detect the formation of intracellular reactive oxygen species （ROS） in the cells.Results P165 significantly protected the HDFs against UVA-induced cytotoxicity.Compared with the UVA-irradiated control,1,10,and 100 μmol/L P165 elevated cell proliferation by 14.98% （P〈0.05）,17.52% （P〈0.01） and 28.34% （P〈0.001）,respectively.Simultaneously,10 and 100 μmol/L P165 increased collagen type Ⅰ content （both P〈0.05）.Moreover,P165 treatment （all concentrations） also markedly suppressed the UVA-induced MMP-1 expression （all P〈0.001）.P165 at 1,10,and 100 μmol/L also reduced UVA-induced ROS generation by 11.27%,13.69% （both P〈0.05）,and 25.48% （P〈0.001）,respectively.Conclusions P165 could protect the HDFs against UVA-induced photodamage,including cytotoxicity,and MMP-1 generation.Furthermore,it also increased the collagen type Ⅰ content in the cells.The inhibitory effect on intracellular ROS generation might be involved in these photoprotective effects.Thus,P165 may be a useful candidate in the prevention and treatment of skin photoaging.展开更多
Alzheimer’s disease(AD)is the most common age-dependent neurodegenerative disease which impairs cognitive function and gradually causes patients to be unable to lead normal daily lives.While the etiology of AD remain...Alzheimer’s disease(AD)is the most common age-dependent neurodegenerative disease which impairs cognitive function and gradually causes patients to be unable to lead normal daily lives.While the etiology of AD remains an enigma,excessive accumulation ofβ-amyloid peptide(Aβ)is widely believed to induce pathological changes and cause dementia in brains of AD patients.BACE1 was discovered to initiate the cleavage of amyloid precursor protein(APP)at theβ-secretase site.Only after this cleavage doesγ-secretase further cleave the BACE1-cleaved C-terminal APP fragment to release Aβ.Hence,blocking BACE1 proteolytic activity will suppress Aβgeneration.Due to the linkage of Aβto the potential cause of AD,extensive discovery and development efforts have been directed towards potent BACE1 inhibitors for AD therapy.With the recent breakthrough in developing brain-penetrable BACE1 inhibitors,targeting amyloid deposition-mediated pathology for AD therapy has now become more practical.This review will summarize various strategies that have successfully led to the discovery of BACE1 drugs,such as MK8931,AZD-3293,JNJ-54861911,E2609 and CNP520.These drugs are currently in clinical trials and their updated states will be discussed.With the promise of reducing Aβgeneration and deposition with no alarming safety concerns,the amyloid cascade hypothesis in AD therapy may finally become validated.展开更多
基金This work was supported in part by a grant from the National Natural Science Foundation of China
文摘Background We showed in our previous study that the N-terminal 17-mer peptide of amyloid precursor protein （APP17-mer peptide）,an active peptide segment with trophic and antioxidative effects,protects skin fibroblasts against ultraviolet （UV） damage and downregulates matrix metalloproteinase 1 （MMP-1） expression.The aim of the current study was to explore the protective effects of P165,the N-terminal 5-mer peptide analog of amyloid precursor protein that is resistant to enzymolysis,on UVA-induced damage in human dermal fibroblasts （HDFs）.Methods HDFs were cultured in Dulbecco＆#39;s modified Eagle＆#39;s medium without and with P165 （concentrations were 1,10,and 100 μJmol/L）.Then,15 J/cm2 UVA irradiation was used to obtain the UV-irradiated model.Cell proliferation was analyzed using MTT kit.The collagen type Ⅰ and MMP-1 contents in cell lysate were determined by enzyme-linked immunosorbent assay （ELISA）.Fluorometric assays were performed to detect the formation of intracellular reactive oxygen species （ROS） in the cells.Results P165 significantly protected the HDFs against UVA-induced cytotoxicity.Compared with the UVA-irradiated control,1,10,and 100 μmol/L P165 elevated cell proliferation by 14.98% （P〈0.05）,17.52% （P〈0.01） and 28.34% （P〈0.001）,respectively.Simultaneously,10 and 100 μmol/L P165 increased collagen type Ⅰ content （both P〈0.05）.Moreover,P165 treatment （all concentrations） also markedly suppressed the UVA-induced MMP-1 expression （all P〈0.001）.P165 at 1,10,and 100 μmol/L also reduced UVA-induced ROS generation by 11.27%,13.69% （both P〈0.05）,and 25.48% （P〈0.001）,respectively.Conclusions P165 could protect the HDFs against UVA-induced photodamage,including cytotoxicity,and MMP-1 generation.Furthermore,it also increased the collagen type Ⅰ content in the cells.The inhibitory effect on intracellular ROS generation might be involved in these photoprotective effects.Thus,P165 may be a useful candidate in the prevention and treatment of skin photoaging.
基金R Yan is supported by the grant(AG025493,MH103942,NS074256 and AG046929)from the National Institutes of Health.
文摘Alzheimer’s disease(AD)is the most common age-dependent neurodegenerative disease which impairs cognitive function and gradually causes patients to be unable to lead normal daily lives.While the etiology of AD remains an enigma,excessive accumulation ofβ-amyloid peptide(Aβ)is widely believed to induce pathological changes and cause dementia in brains of AD patients.BACE1 was discovered to initiate the cleavage of amyloid precursor protein(APP)at theβ-secretase site.Only after this cleavage doesγ-secretase further cleave the BACE1-cleaved C-terminal APP fragment to release Aβ.Hence,blocking BACE1 proteolytic activity will suppress Aβgeneration.Due to the linkage of Aβto the potential cause of AD,extensive discovery and development efforts have been directed towards potent BACE1 inhibitors for AD therapy.With the recent breakthrough in developing brain-penetrable BACE1 inhibitors,targeting amyloid deposition-mediated pathology for AD therapy has now become more practical.This review will summarize various strategies that have successfully led to the discovery of BACE1 drugs,such as MK8931,AZD-3293,JNJ-54861911,E2609 and CNP520.These drugs are currently in clinical trials and their updated states will be discussed.With the promise of reducing Aβgeneration and deposition with no alarming safety concerns,the amyloid cascade hypothesis in AD therapy may finally become validated.
