The present study aimed to investigate the targeting effect of H7K（R2）2-modified pH -sensitive liposomes on U87-MG cells. Using coumarin-6 as a fluorescence probe, we prepared H7K（R2）2-modified p H-sensitive lipos...The present study aimed to investigate the targeting effect of H7K（R2）2-modified pH -sensitive liposomes on U87-MG cells. Using coumarin-6 as a fluorescence probe, we prepared H7K（R2）2-modified p H-sensitive liposomes（designated as coumarin-6-PSL-H7K（R2）2）. The flow cytometry assay was used to evaluate the effect of H7K（R2）2 proportions on the cellular uptake and endocytosis pathways of coumarin--6--PSL--H7K（R2）2 on U87-MG cells. The circular dichroism（CD） spectroscopy assay was used to investigate the secondary structures of H7K（R2）2 peptide at pH 7.4 and H 6.8, respectively. Our results indicated that the 2.5% proportion of H7K（R2）2 in the coumarin-6--PSL-H7K（R2）2 was superior to those of 1% and 3.5% of H7K（R2）2. The uptake of coumarin--6-PSL--H7K（R2）2 on U87--MG cells was not inhibited by filipin, M-β--CD or chlorpromazine. The secondary structure of H7K（R2）2 at pH 6.8 was mostly presented as β--turn. In conclusion, we suggested that the appropriate proportion of H7K（R2）2 in the H7K（R2）2--modified pH--sensitive liposomes could be set at 2.5%. The cellular uptake pathway for H7K（R2）2-modified pH--sensitive liposomes was via the cell penetrating capacity of H7K（R2）2 which responded to acidic condition. The secondary structure of H7K（R2）2 at pH 6.8, which was presented as the shape of hairpin, might be mainly responsible for its targeting and cell penetrating effect.展开更多
Sesquiterpenoids are a class of 15-carbon secondary metabolites that play diverse roles in plant adaptation to environment. Cotton plants accumulate a large amount of sesquiterpene aldehydes （including gossypol） as ...Sesquiterpenoids are a class of 15-carbon secondary metabolites that play diverse roles in plant adaptation to environment. Cotton plants accumulate a large amount of sesquiterpene aldehydes （including gossypol） as phytoalexins against pathogens and herbivores. They are stored in pigment glands of aerial organs and in epidermal layers of roots. Several enzymes of goss- ypol biosynthesis pathway have been characterized, including 3-hydroxy-3-methylglutaryl coenzyme A reductase （HMGR） and farnesyl diphosphate synthase （FPS） that catalyze the formation of the precursor farnesyl diphosphate （FPP）, （＋）-6-cadinene synthase （CDN） which is the first enzyme committed to gossypol biosynthesis, and the downstream enzymes of CYP706B 1 and methyltransferase. Expressions of these genes are tightly regulated during cotton plants development and in- duced by jasmonate and fungi elicitors. The transcription factor GaWRKY1 has been shown to be involved in gossypol path- way regulation. Recent development of new genomic platforms and methods and releases of diploid and tetraploid cotton ge- nome sequences will greatly facilitate the elucidation of gossypol biosynthetic pathway and its regulation.展开更多
基金Specialized Research Fund for the Doctoral Program of Higher Education(Grant No.20120001110012)the National Basic Research Program of China(973 Program,Grant No.2013CB932501)National Natural Science Foundation of China(Grant No.81172992)
文摘The present study aimed to investigate the targeting effect of H7K（R2）2-modified pH -sensitive liposomes on U87-MG cells. Using coumarin-6 as a fluorescence probe, we prepared H7K（R2）2-modified p H-sensitive liposomes（designated as coumarin-6-PSL-H7K（R2）2）. The flow cytometry assay was used to evaluate the effect of H7K（R2）2 proportions on the cellular uptake and endocytosis pathways of coumarin--6--PSL--H7K（R2）2 on U87-MG cells. The circular dichroism（CD） spectroscopy assay was used to investigate the secondary structures of H7K（R2）2 peptide at pH 7.4 and H 6.8, respectively. Our results indicated that the 2.5% proportion of H7K（R2）2 in the coumarin-6--PSL-H7K（R2）2 was superior to those of 1% and 3.5% of H7K（R2）2. The uptake of coumarin--6-PSL--H7K（R2）2 on U87--MG cells was not inhibited by filipin, M-β--CD or chlorpromazine. The secondary structure of H7K（R2）2 at pH 6.8 was mostly presented as β--turn. In conclusion, we suggested that the appropriate proportion of H7K（R2）2 in the H7K（R2）2--modified pH--sensitive liposomes could be set at 2.5%. The cellular uptake pathway for H7K（R2）2-modified pH--sensitive liposomes was via the cell penetrating capacity of H7K（R2）2 which responded to acidic condition. The secondary structure of H7K（R2）2 at pH 6.8, which was presented as the shape of hairpin, might be mainly responsible for its targeting and cell penetrating effect.
基金the State Key Basic Research Program of China (2013CB127000)the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB11030300)+1 种基金the National Natural Science Foundation of China (31300255)the Special Fund for Shanghai Landscaping Administration Bureau Program (G142425, F112418).
文摘Sesquiterpenoids are a class of 15-carbon secondary metabolites that play diverse roles in plant adaptation to environment. Cotton plants accumulate a large amount of sesquiterpene aldehydes （including gossypol） as phytoalexins against pathogens and herbivores. They are stored in pigment glands of aerial organs and in epidermal layers of roots. Several enzymes of goss- ypol biosynthesis pathway have been characterized, including 3-hydroxy-3-methylglutaryl coenzyme A reductase （HMGR） and farnesyl diphosphate synthase （FPS） that catalyze the formation of the precursor farnesyl diphosphate （FPP）, （＋）-6-cadinene synthase （CDN） which is the first enzyme committed to gossypol biosynthesis, and the downstream enzymes of CYP706B 1 and methyltransferase. Expressions of these genes are tightly regulated during cotton plants development and in- duced by jasmonate and fungi elicitors. The transcription factor GaWRKY1 has been shown to be involved in gossypol path- way regulation. Recent development of new genomic platforms and methods and releases of diploid and tetraploid cotton ge- nome sequences will greatly facilitate the elucidation of gossypol biosynthetic pathway and its regulation.
