Apple ethanol extract promotes proliferation of human adult stem cells, which involves the regenerative potential of stem cells.

Tissue regeneration using adult stem cells (ASCs) has significant potential as a novel treatment for many degenerative diseases. Previous studies have established that age negatively affects the proliferation status and differentiation potential of ASCs, suggesting a possible limitation in their potential therapeutic use. Therefore, we hypothesized that apple extract might exert beneficial effects on ASCs. The specific objectives were to investigate the proliferative effect of apple ethanol extract on human adipose tissue-derived mesenchymal stem cells (ADSCs) and human cord blood-derived mesenchymal stem cells (CB-MSCs), and identify the possible molecular mechanisms. Apple extract promoted proliferation of ADSCs and CB-MSCs as determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and Click-iT 5-ethynyl-2'-deoxyuridine flow cytometry assays. In addition, phosphorylation of p44/42 MAPK (ERK), mammalian target of rapamycin (mTOR), p70 S6 kinase (p70S6K), S6 ribosomal protein (S6RP), eukaryotic initiation factor (eIF) 4B and eIF4E was induced stepwise in ADSCs. Furthermore, apple extract significantly induced the production of vascular endothelial growth factor and interleukin-6 in both ADSCs and CB-MSCs. Similarly, apple extract-induced phosphorylation of the mTOR/p70S6K/S6RP/eIF4B/eIF4E pathway was blocked by pretreatment with PD98059, a specific ERK inhibitor. These results indicate that apple extract-induced proliferation of ADSCs under serum-free conditions is mediated by ERK-dependent cytokine production. Moreover, the beneficial effect of apple extract on proliferation of ASCs may overcome the limitation in therapeutic use of stem cells in tissue regeneration and maintenance of stem cell homeostasis.

Phloridzin isolated from Acanthopanax senticosus promotes proliferation of α6 integrin (CD 49f) and ß1 integrin (CD29) enriched for a primary keratinocyte population through the ERK-mediated mTOR pathway.

We investigated the proliferative effect of a Acanthopanax senticosus extract (ASE) on human CD49f(+)/CD29(+) keratinocytes and isolated phloridzin from A. senticosus as an active compound. In addition, the possible mechanisms of action were examined. We found that the ASE and phloridzin-promoted proliferation of CD49f(+)/CD29(+) cells using MTT and Click-iT™ EdU flow cytometry assays. In addition, phosphorylation of the p44/42 MAPK (ERK), mTOR, p70 S6 kinase (p70S6K), S6 ribosomal protein (S6RP), eukaryotic initiation factor 4B (eIF4B), and eIF4E was stepwise induced in CD49f(+)/CD29(+) cells. Furthermore, the ASE and phloridzin significantly induced the production of vascular endothelial growth factor and interleukin-6 in CD49f(+)/CD29(+) cells. Similarly, ASE and phloridzin-induced phosphorylation of the mTOR/p70S6K/S6RP/eIF4B/eIF4E pathway was blocked in response to pretreatment with PD98059, a specific ERK inhibitor. Taken together, these results indicate that ASE and phloridzin-induced proliferation of CD49f(+)/CD29(+) cells under serum-free conditions was mediated by the ERK-dependent mTOR pathway.

Mechanisms of Edible Bird's Nest Extract-Induced Proliferation of Human Adipose-Derived Stem Cells.

Although edible bird's nest (EBN) has been shown to potentiate mitogenic responses, scientific evidence of its efficacy is still limited. In addition, human adipose-derived stem cells (hADSCs) are increasingly accepted as a source for stem cell therapy. Therefore, the aim of this study was to investigate the effects of the EBN extract (EBNE) on the proliferation of hADSCs and its action mechanisms. We found that EBNE strongly promoted the proliferation of hADSCs. In addition, EBNE-induced proliferation was found to be mediated through the production of IL-6 and VEGF, which was induced by activation of AP-1 and NF-κB. Specially, we found that production of IL-6 and VEGF was induced by EBNE. In addition, EBNE-induced production of IL-6 and VEGF was inhibited by PD98059 (a p44/42 MAPK inhibitor), SB203580 (a p38 MAPK inhibitor), and PDTC (a NF-κB inhibitor), but not SP600125 (a JNK inhibitor). Similarly, EBNE-induced proliferation of hADSCs was also attenuated by PD98059, SB203580, and PDTC but not SP600125. Taken together, these findings suggest that the EBNE-induced proliferation of hADSCs primarily occurs through increased expression of IL-6 and VEGF genes, which is mediated by the activation of NF-κB and AP-1 through p44/42 MAPK and p38 MAPK.

A cell-based system for screening hair growth-promoting agents.

Androgen-inducible transforming growth factor beta (TGF-beta1) derived from dermal papilla cells (DPCs) is a catagen inducer that mediates hair growth suppression in androgenetic alopecia (AGA). In this study, a cell-based assay system was developed to monitor TGF-beta1 promoter activity and then used to evaluate the effects of activated TGF-beta1 promoter in human epidermal keratinocytes (HaCaT). To accomplish this, a pMetLuc-TGF-beta1 promoter plasmid that expresses the luciferase reporter gene in response to TGF-beta1 promoter activity was constructed. Treatment of HaCaT with dihydrotestosterone, which is known to be a primary factor of AGA, resulted in a concentration-dependent increase in TGF-beta1 promoter activity. However, treatment of HaCaT with the TGF-beta1 inhibitor, curcumin, resulted in a concentration-dependant decrease in TGF-beta1 expression. Subsequent use of this assay system to screen TGF-beta1 revealed that HaCaT that were treated with apigenin showed decreased levels of TGF-beta1 expression. In addition, treatment with apigenin also significantly increased the proliferation of both SV40T-DPCs (human DPCs) and HaCaT cells. Furthermore, apigenin stimulated the elongation of hair follicles in a rat vibrissa hair follicle organ culture. Taken together, these findings suggest that apigenin, which is known to have antioxidant, anti-inflammatory, and anti-tumor properties, stimulates hair growth through downregulation of the TGF-beta1 gene. In addition, these results suggest that this assay system could be used to quantitatively measure TGF-beta1 promoter activity in HaCaT, thereby facilitating the screening of agents promoting hair growth.

Ondamtanggamibang protects neurons from oxidative stress with induction of heme oxygenase-1.

Ondamtanggamibang (ODG) has been used as a remedy to treat psychological anxiety and depression in Oriental medicine. In this study, we found the protective effects of ODG against oxidative stress by induction of the antioxidative enzyme, heme oxygenase (HO)-1 in neuronal PC12 cells. Pretreatment with ODG extract protected neuronal cells from damage induced by H(2)O(2) and 6-hydroxydopamine (6-OHDA), but simultaneous treatment with ODG extract did not. ODG also inhibited the intracellular reactive oxygen species elevation by H(2)O(2) and 6-OHDA. ODG stimulation strongly induced the expression of HO-1 in PC12 cells. The protective effect of ODG extract on oxidative stress-induced damage was suppressed by HO inhibitor, zinc protoporphyrin IX (ZnPP-IX). Taken together, these data suggest that ODG treatment has potential protective effects in neuronal cells under oxidative stress.

Involvement of hydrogen peroxide in mistletoe lectin-II-induced apoptosis of myeloleukemic U937 cells.

Mistletoe lectin-II, a major component of Korean mistletoe (Viscum album var. coloratum) induces apoptotic death in cancer cells. In this study, we demonstrated that lectin-II induced the generation of pro-oxidants and thus resulted in the apoptotic death of human myeloleukemic U937 cells. We observed that lectin-II-induced apoptotic death was inhibited by antioxidants including reduced glutathione (GSH), N-acetylcysteine (NAC), ebselen, mnTBP, catalase and pyrrolidine dithiocarbamate (PDTC). GSH and NAC also abolished the apoptotic DNA ladder pattern fragmentation of U937 cells after lectin-II stimulation. Obviously, lectin-II treatment of cells resulted in a remarkable generation of intracellular hydrogen peroxide (H2O2) as an early event, which was monitored fluorimetrically using scopoletin-horse radish peroxidase (HRP) assay and peroxide-sensitive fluorescent probe, DCF-DA. In addition, antioxidants inhibited the activation of c-Jun N-terminal kinase (JNK)/stress-activated protein kinase (SAPK) as well as cytosolic release of cytochrome c by mistletoe lectin-II. Moreover, lectin-II-induced activation of caspase-9 and 3-like protease and cleavage of poly(ADP-ribose) polymerase (PARP) were inhibited by pretreatment of cells with thiol antioxidants, GSH and NAC. Taken together, these results suggest that Korean mistletoe lectin-II is a strong inducer of pro-oxidant generation such as H2O2, which mediates the JNK/SAPK activation, cytochrome c release, activation of caspase-9 and caspase 3-like protease, and PARP cleavage in human myeloleukemic U937 cells.

Protective effects of Debo on serum-deprived apoptosis of PC12 cells via inhibition of H2O2 generation and caspase 3-like protease activity.

Oxidative stress can be induced neurotoxic insults by increasing intracellular H2O2, which has been implicated in various neurodegenerative diseases in aging. We investigated the mechanism by which Debo protects PC12 cells from serum deprivation-induced apoptosis. PC12 cells underwent apoptotic death in association with increase in caspase 3-like activity, DNA fragmentation, H2O2 production, GSH depletion, and NF-kappaB activation after 24 hr of serum withdrawal. Debo protected cells from a serum deprivation-induced cytotoxicity in a dose dependent manner. Debo recovered the intracellular GSH level decreased by serum deprivation in PC12 cells. Also, Debo inhibited the activation of caspase 3-like protease of serum-deprived PC12 cells in a dose dependent manner. Furthermore, Debo inhibited the transcriptional activation of NF-kappaB by serum deprivation. These findings indicate that Debo may protect PC12 cells against apoptosis by serum deprivation via generation of intracellular GSH to scavenge oxidative radicals including H2O2.