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1.
J Cosmet Dermatol ; 23(2): 529-542, 2024 Feb.
Article in English | MEDLINE | ID: mdl-37675655

ABSTRACT

BACKGROUND: Natural components that can exert a wide range of anti-hair loss activity with fewer side effects are in high demand. The objective of this study was to investigate the anti-hair loss potential of Silybum marianum flower extract (SMFE) in vitro and in vivo. METHODS: The effect of SMFE on dermal papilla cells was evaluated by measuring cell proliferation and VEGF production in hair follicle dermal papilla cells (HFDPCs). In addition, to confirm the effect of SMFE on dermal papilla senescence, SA-ß-gal staining and senescence associated secretory phenotype (SASP) production such as IL-6 was observed in both replicative and hydrogen peroxide (H2 O2 )-induced senescence models. In a clinical study, hair growth was determined by reconstitution analysis after shaving the hair of the clinical subject's scalp and hair area. RESULTS: SMFE increased the proliferation and VEGF production of HFDPCs. It also suppressed cellular senescence of HFDPCs and IL-6 production in replicative senescence and oxidative stress-induced senescence models. The hair density and total hair count at 16 and 24 weeks after using hair shampoo containing SMFE were significantly increased compared with those of the placebo group. CONCLUSION: SMFE has the potential to be used as a natural ingredient for alleviating hair loss.


Subject(s)
Interleukin-6 , Silybum marianum , Humans , Vascular Endothelial Growth Factor A/genetics , Hair Follicle , Alopecia/drug therapy , Flowers , Cells, Cultured
2.
Mol Med Rep ; 27(6)2023 Jun.
Article in English | MEDLINE | ID: mdl-37203390

ABSTRACT

Integrins act as cell­matrix adhesion molecules involved in cell attachment to the extracellular matrix and generate signals that respond to cancer metastasis. Integrin α5ß1 is a heterodimer with α5 and ß1 subunits and mediates cell adhesion and migration of cancer cells. Integrins are transcriptionally regulated by the Janus kinase (JAK)/STAT signaling pathways. Our previous study revealed that Helicobacter pylori increased the levels of reactive oxygen species (ROS), which activate JAK1/STAT3 in gastric cancer AGS cells in vitro. Astaxanthin (ASX) has been reported to be an effective antioxidant and anticancer nutrient. The present study investigated whether ASX suppresses H. pylori­induced integrin α5 expression, cell adhesion and migration and whether ASX reduces ROS levels and suppresses phosphorylation of JAK1/STAT3 in gastric cancer AGS cells stimulated with H. pylori. The effect of ASX was determined using a dichlorofluorescein fluorescence assay, western blot analysis, adhesion assay and wound­healing assay in AGS cells stimulated with H. pylori. The results demonstrated that H. pylori increased the expression levels of integrin α5, without affecting integrin ß1, and increased cell adhesion and migration of AGS cells. ASX reduced ROS levels and suppressed JAK1/STAT3 activation, integrin α5 expression, cell adhesion and migration of H. pylori­stimulated AGS cells. In addition, both a JAK/STAT inhibitor, AG490, and an integrin α5ß1 antagonist, K34C, suppressed cell adhesion and migration in H. pylori­stimulated AGS cells. AG490 inhibited integrin α5 expression in AGS cells stimulated with H. pylori. In conclusion, ASX inhibited H. pylori­induced integrin α5­mediated cell adhesion and migration by decreasing the levels of ROS and suppressing JAK1/STAT3 activation in gastric epithelial cells.


Subject(s)
Helicobacter pylori , Stomach Neoplasms , Humans , Epithelial Cells/metabolism , Gastric Mucosa/metabolism , Helicobacter pylori/physiology , Integrin alpha5/metabolism , Integrin alpha5beta1/metabolism , Janus Kinase 1/metabolism , Reactive Oxygen Species/metabolism , STAT3 Transcription Factor/metabolism , Stomach Neoplasms/pathology
3.
Int J Cosmet Sci ; 45(2): 155-165, 2023 Apr.
Article in English | MEDLINE | ID: mdl-36411959

ABSTRACT

OBJECTIVE: Hair loss is caused by various factors. Impacts of these factors are often overlapped and intensified. Currently, mitigation of hair loss is being studied by proliferating dermal papilla cells (DPCs) and inhibiting deleterious factors such as dihydrotestosterone (DHT) and oxidative stress on hair growth. Camellia japonica (C. japonica) fruit shell is a discarded part. Its biological activity remains to be elucidated. In this study, we investigated the capacity of C. japonica fruit shell extract (CJFSE) for hair loss mitigation. METHODS: MTT assay, spheroid culture and quantitative RT-PCR were performed to observe the proliferative effect of CJFSE on hair follicle dermal papilla cells (HFDPCs). Effects of CJFSE on DHT-induced hair loss were confirmed by Dkk-1 ELISA, ß-galactosidase (ß-gal) and 5α-reductase activity assay. In addition, effects of CJFSE on oxidative stress were confirmed through DPPH and ROS production assays. RESULTS: CJFSE increased the proliferation and spheroid size of HFDPCs. Expression levels of VEGF-A, Wnt-1, c-Myc and Cyclin D1 were upregulated by CJFSE. CJFSE also suppressed 5α-reductase activity and DHT-induced decrease in cell proliferation, Dkk-1 secretion and ß-gal activity. Moreover, CJFSE showed DPPH scavenging activity and ameliorated hydrogen peroxide-induced ROS production and ß-gal activity. Finally, gallic acid and protocatechuic acid were observed in CJFSE through HPLC analysis. CONCLUSION: CJFSE has the potential to alleviate hair loss by promoting hair cell growth and suppressing effects of DHT and oxidative stress on hair.


OBJECTIF: Divers facteurs sont responsables de la perte de cheveux. Souvent, les conséquences de ces facteurs se superposent et s'intensifient. Actuellement, on étudie comment atténuer la perte de cheveux en faisant proliférer les cellules de la papille dermique (DPC) et en inhibant les facteurs délétères tels que la dihydrotestostérone (DHT) et le stress oxydatif sur la croissance des cheveux. La coque du fruit du Camélia du Japon (Camelia japonica) est habituellement rejetée. Son utilité biologique reste à élucider. Dans cette étude, nous avons étudié la capacité de l'extrait de la coque du fruit du Camélia du Japon (CJFSE) dans la mitigation de la perte de cheveux. MÉTHODES: Un test MTT, une culture de sphéroïdes et une RT-PCR Quantitative ont été effectués pour observer la prolifération de CJFSE sur les cellules de la papille dermique du follicule pileux (HFDPC). Les effets du CJFSE sur la perte de cheveux induite par la DHT ont été confirmés par Dkk-1 ELISA, ß-galactosidase (ß-gal) et 5α-réductase. De plus, les effets du CJFSE sur le stress oxydatif ont été confirmés par des tests de production de DPPH et de ROS. RÉSULTATS: Le CJFSE a augmenté la prolifération et la taille sphéroïde des HFDPC. Les niveaux d'expression de VEGF-A, Wnt-1, c-Myc et cycline D1 ont été régulés de manière efficace par le CJFSE. Le CJFSE a également supprimé l'activité de la 5α-réductase et a induit la réduction de la DHT et de la prolifération cellulaire, ainsi que de la sécrétion de Dkk-1 et de l'activité ß-gal. Le CJFSE a en outre montré une activité de capture du DPPH et amélioré la production de ROS induite par le peroxyde d'hydrogène et l'activité ß-gal. Pour finir, les acides gallique et protocatéchuique ont été observés dans le CJFSE après analyse des HPLC. CONCLUSION: Le CJFSE a le potentiel d'atténuer la perte de cheveux en favorisant la croissance des cellules ciliées et en supprimant les effets de la DHT et du stress oxydatif sur les cheveux.


Subject(s)
Alopecia , Fruit , Reactive Oxygen Species , Dihydrotestosterone/adverse effects , Plant Extracts/pharmacology , Oxidoreductases
4.
Nutrients ; 14(9)2022 May 09.
Article in English | MEDLINE | ID: mdl-35565945

ABSTRACT

Senescent fibroblasts progressively deteriorate the functional properties of skin tissue. Senescent cells secrete senescence-associated secretory phenotype (SASP) factor, which causes the aging of surrounding non-senescent cells and accelerates aging in the individuals. Recent findings suggested the senomorphic targeting of the SASP regulation as a new generation of effective therapeutics. We investigated whether Isatis tinctoria L. leaf extract (ITE) inhibited senescence biomarkers p53, p21CDKN1A, and p16INK4A gene expression, and SASP secretions by inhibiting cellular senescence in the replicative senescent human dermal fibroblast (RS-HDF). ITE has been demonstrated to inhibit the secretion of SASP factors in several senomorphic types by regulating the MAPK/NF-κB pathway via its inhibitory effect on mTOR. ITE suppressed the inflammatory response by inhibiting mTOR, MAPK, and IκBα phosphorylation, and blocking the nuclear translocation of NF-κB. In addition, we observed that autophagy pathway was related to inhibitory effect of ITE on cellular senescence. From these results, we concluded that ITE can prevent and restore senescence by blocking the activation and secretion of senescence-related factors generated from RS-HDFs through mTOR-NF-κB regulation.


Subject(s)
Isatis , NF-kappa B , Cellular Senescence , Fibroblasts , Isatis/metabolism , NF-kappa B/metabolism , Plant Extracts/metabolism , Plant Extracts/pharmacology , Senotherapeutics , TOR Serine-Threonine Kinases/metabolism
5.
Molecules ; 27(7)2022 Mar 24.
Article in English | MEDLINE | ID: mdl-35408493

ABSTRACT

Advanced glycation end products (AGEs) have recently been increasingly discussed as one factor of skin aging. In this study, we investigated the effects of Cirsium japonicum flower (CFE) extract on glycation in relation to skin aging and skin elasticity. Moreover, we learned the main active constituent of CFE that has effects against glycation. To demonstrate the effects of CFE on glycation, we carried out an in vitro glycation study, 3-dimensional culture, and clinical study. As a result, CFE inhibited formation of AGEs in both bovine serum albumin (BSA)/glucose glycation system and aldehyde-derived glycation system. Moreover, CFE reduced Nε-(carboxymethyl), lysine (CML), and carbonylated proteins that increased by glycation. Furthermore, CFE broke crosslinks of collagen-AGEs and inhibited the increase of matrix metalloproteinase-1 (MMP-1) gene expression by AGEs. In the 3D culture condition, CFE restored the reduction of collagen gel contraction by glycation. Moreover, apigenin was detected as the main active constituent in CFE that has anti-glycation effects. In the clinical study, we confirmed that CFE has effects on skin wrinkles and skin elasticity. Our findings suggest that CFE can be used as a cosmetic or cosmeceutical ingredient for improving skin elasticity and wrinkles. Regulation of AGEs can be an interesting target for anti-aging.


Subject(s)
Cirsium , Plant Extracts , Skin Aging , Cirsium/chemistry , Collagen , Flowers/chemistry , Glycation End Products, Advanced/metabolism , Humans , Plant Extracts/pharmacology
6.
Clin Cosmet Investig Dermatol ; 15: 433-445, 2022.
Article in English | MEDLINE | ID: mdl-35313536

ABSTRACT

Purpose: Changes in facial appearance are affected by various intrinsic and extrinsic factors, which vary from person to person. Therefore, each person needs to determine their skin condition accurately to care for their skin accordingly. Recently, genetic identification by skin-related phenotypes has become possible using genome-wide association studies (GWAS) and machine-learning algorithms. However, because most GWAS have focused on populations with American or European skin pigmentation, large-scale GWAS are needed for Asian populations. This study aimed to evaluate the correlation of facial phenotypes with candidate single-nucleotide polymorphisms (SNPs) to predict phenotype from genotype using machine learning. Materials and Methods: A total of 749 Korean women aged 30-50 years were enrolled in this study and evaluated for five facial phenotypes (melanin, gloss, hydration, wrinkle, and elasticity). To find highly related SNPs with each phenotype, GWAS analysis was used. In addition, phenotype prediction was performed using three machine-learning algorithms (linear, ridge, and linear support vector regressions) using five-fold cross-validation. Results: Using GWAS analysis, we found 46 novel highly associated SNPs (p < 1×10-05): 3, 20, 12, 6, and 5 SNPs for melanin, gloss, hydration, wrinkle, and elasticity, respectively. On comparing the performance of each model based on phenotypes using five-fold cross-validation, the ridge regression model showed the highest accuracy (r2 = 0.6422-0.7266) in all skin traits. Therefore, the optimal solution for personal skin diagnosis using GWAS was with the ridge regression model. Conclusion: The proposed facial phenotype prediction model in this study provided the optimal solution for accurately predicting the skin condition of an individual by identifying genotype information of target characteristics and machine-learning methods. This model has potential utility for the development of customized cosmetics.

7.
Anim Cells Syst (Seoul) ; 26(6): 310-317, 2022.
Article in English | MEDLINE | ID: mdl-36605596

ABSTRACT

Natural products and their derivatives historically represent alternatives to conventional synthetic molecules for pharmacotherapy, ranging from cancer chemotherapeutics to cosmetic ingredients that exert anti-aging activities. Cellular senescence is considered a main driver of skin aging, yet natural products that target skin senescence in a specific manner are not thoroughly explored. Here, we performed a focused compound screen to identify natural products that exert anti-senescence effects. We found that Isatis tinctoria, woad extracts, displayed a senolytic effect on senescent human skin fibroblasts. Furthermore, treatment with woad extracts attenuated the expression of pro-inflammatory senescence-associated secretory phenotype (SASP), showing a senostatic activity. Intriguingly, woad extracts displayed only a marginal cytotoxic effect toward senescent human lung fibroblasts. Thus, our results reveal the potential activities of woad extracts for targeting skin senescence and suggest that woad extracts could be an attractive ingredient for cosmetics to prevent skin aging.

8.
PLoS One ; 16(12): e0260545, 2021.
Article in English | MEDLINE | ID: mdl-34914725

ABSTRACT

Cellular senescence causes irreversible growth arrest of cells. Prolonged accumulation of senescent cells in tissues leads to increased detrimental effects due to senescence associated secretory phenotype (SASP). Recent findings suggest that elimination of senescent cells has a beneficial effect on organismal aging and lifespan. In this study, using a validated replicative senescent human dermal fibroblasts (HDFs) model, we showed that elimination of senescent cells is possible through the activation of an apoptotic mechanism. We have shown in this replicative senescence model, that cell senescence is associated with DNA damage and cell cycle arrest (p21, p53 markers). We have shown that Silybum marianum flower extract (SMFE) is a safe and selective senolytic agent targeting only senescent cells. The elimination of the cells is induced through the activation of apoptotic pathway confirmed by annexin V/propidium iodide and caspase-3/PARP staining. Moreover, SMFE suppresses the expression of SASP factors such as IL-6 and MMP-1 in senescent HDFs. In a co-culture model of senescent and young fibroblasts, we demonstrated that senescent cells impaired the proliferative capacities of young cells. Interestingly, when the co-culture is treated with SMFE, the cell proliferation rate of young cells is increased due to the decrease of the senescent burden. Moreover, we demonstrated in vitro that senescent fibroblasts trigger senescent process in normal keratinocytes through a paracrine effect. Indeed, the conditioned medium of senescent HDFs treated with SMFE reduced the level of senescence-associated beta-galactosidase (SA-ß-Gal), p16INK4A and SASP factors in keratinocytes compared with CM of senescent HDFs. These results indicate that SMFE can prevent premature aging due to senescence and even reprograms aged skin. Indeed, thanks to its senolytic and senomorphic properties SMFE is a candidate for anti-senescence strategies.


Subject(s)
Cellular Senescence/drug effects , Plant Extracts/pharmacology , Silybum marianum/chemistry , Apoptosis/drug effects , Cell Cycle Checkpoints/drug effects , Cell Line , Cell Survival/drug effects , DNA Damage/drug effects , Dermis/cytology , Fibroblasts/cytology , Fibroblasts/metabolism , Flowers/chemistry , Flowers/metabolism , Humans , Silybum marianum/metabolism , Phytochemicals/analysis , Plant Extracts/chemistry , Senescence-Associated Secretory Phenotype/drug effects
9.
J Craniofac Surg ; 29(5): 1266-1270, 2018 Jul.
Article in English | MEDLINE | ID: mdl-29905581

ABSTRACT

Torticollis could be the only symptom and sign of craniovertebral junction (CVJ) abnormality. It could be difficult to identify CVJ abnormality as a cause of torticollis due to their rarity, especially for the subjects with torticollis caused by nontraumatic CVJ abnormalities. There has been no report to focus on nontraumatic CVJ abnormalities as a cause of torticollis. The objective of this study was to report 27 patients of torticollis caused by nontraumatic CVJ abnormalities, with the aim of helping clinicians to identify nontraumatic CVJ abnormalities as a cause of torticollis. This is a retrospective cohort study including 27 subjects who had torticollis caused by nontraumatic CVJ abnormalities. The CVJ was examined in terms of atlanto-occipital angle, atlanto-axial angle, and lateral and anterior atlanto-dens intervals for the evaluation of occipital condylar hypoplasia, rotation of atlanto-axial joint, and lateral and anterior shift of the dens, respectively. Abnormalities of the lower cervical or thoracic spine were also evaluated. Occipital condylar hypoplasia, rotation of atlanto-axial joint, and lateral shift of the dens were the most common CVJ abnormalities. The 18.5% of the subjects had concurrent anomalies of lower cervical or thoracic vertebrae along with CVJ abnormalities. Each subject had 2.22 ±â€Š1.10 types of CVJ abnormalities on average. In conclusion, comprehensive evaluation of CVJ abnormalities is recommended for differential diagnosis of subjects with unexplained torticollis. Once CVJ abnormalities are identified, concurrent abnormalities of other vertebrae need to be evaluated.


Subject(s)
Atlanto-Axial Joint/abnormalities , Atlanto-Occipital Joint/abnormalities , Occipital Bone/abnormalities , Odontoid Process/abnormalities , Torticollis/etiology , Adolescent , Adult , Child , Child, Preschool , Female , Humans , Infant , Male , Musculoskeletal Abnormalities/complications , Retrospective Studies , Thoracic Vertebrae/abnormalities , Young Adult
10.
J Craniofac Surg ; 29(3): e327-e331, 2018 May.
Article in English | MEDLINE | ID: mdl-29485567

ABSTRACT

Our clinical experience led us to realize that craniovertebral junction (CVJ) abnormalities were common in surgical patients with congenital muscular torticollis (CMT). This study aimed to report the concurrence rate of CVJ abnormalities in surgical patients with CMT, along with comprehensive evaluation of type of concurrent CVJ abnormalities. This was a retrospective cohort study in a tertiary hospital, including 41 subjects who underwent surgical release for CMT at the mean age of 8.38 years. The presence of CVJ abnormalities was analyzed, using craniofacial 3-dimensional computed tomography images. The concurrence rate of CVJ abnormalities was 70% in surgical patients with CMT. Subjects with CVJ abnormalities had, on average, 1.48 abnormalities. The CVJ abnormalities were rotation and lateral shift of the atlanto-axial joint along with rotation of atlanto-occipital joint, where rotation of the atlanto-axial joint was most common (82.76%). There is no patient with anterior shift of the atlanto-axial joint. Chronic mechanical tension by the contracted unilateral sternocleidomastoid muscle of CMT could be responsible for concurrent CVJ abnormalities. The CVJ abnormalities are more common in the atlanto-axial joint than in the atlanto-occipital joint. In conclusions, CVJ abnormality seems to be a common concurrent skeletal complication of CMT, at least, in surgical patients. The CVJ abnormality might be included in the list of skeletal complications of CMT. If CVJ abnormalities are significantly more common in surgical patients with CMT, CVJ abnormalities might be one of predictors of surgical patients with CMT.


Subject(s)
Abnormalities, Multiple/diagnostic imaging , Atlanto-Axial Joint/abnormalities , Atlanto-Occipital Joint/abnormalities , Torticollis/congenital , Adolescent , Atlanto-Axial Joint/diagnostic imaging , Atlanto-Occipital Joint/diagnostic imaging , Child , Child, Preschool , Female , Humans , Imaging, Three-Dimensional , Male , Retrospective Studies , Tomography, X-Ray Computed , Torticollis/surgery , Young Adult
11.
Ann Rehabil Med ; 39(3): 440-50, 2015 Jun.
Article in English | MEDLINE | ID: mdl-26161351

ABSTRACT

OBJECTIVE: To evaluate the craniofacial asymmetry in adults with neglected congenital muscular torticollis (CMT) by quantitative assessment based on craniofacial three-dimensional computed tomography (3D-CT). METHODS: Preoperative craniofacial asymmetry was measured by 3D-CT for 31 CMT subjects ≥18 years of age who visited a tertiary medical center and underwent 3D-CT between January 2009 and December 2013. The relationship between the age and the severity of craniofacial asymmetry was analyzed in reference to anteroposterior length asymmetry of the frontal bone and zygomatic arch, vertical and lateral displacements of the facial landmarks, and mandibular axis rotation. RESULTS: The age at CT was 27.71±7.02 years (range, 18-44 years). All intra-class correlation coefficients were higher than 0.7, suggesting good inter-rater reliability (p<0.05) of all the measurements. The frontal and the zygomatic length ratio (i.e., the anteroposterior length asymmetry on the axial plane) was 1.06±0.03 and 1.07±0.03, respectively, which was increased significantly with age in the linear regression analysis (r(2)=0.176, p=0.019 and r(2)=0.188, p=0.015, respectively). The vertical or lateral displacement of the facial landmarks and rotation of the mandibular axis did not significantly correlate with age (p>0.05). CONCLUSION: Craniofacial asymmetry of neglected CMT became more severe with age in terms of anteroposterior length asymmetry of the ipsilateral frontal bone and zygomatic arch on the axial plane even after growth cessation. This finding may enhance the understanding of therapeutic strategies for craniofacial asymmetry in adults with neglected CMT.

12.
J Immunol ; 172(11): 7008-14, 2004 Jun 01.
Article in English | MEDLINE | ID: mdl-15153522

ABSTRACT

We studied the intracellular events associated with pancreatic beta cell apoptosis by IFN-gamma/TNF-alpha synergism. IFN-gamma/TNF-alpha treatment of MIN6N8 insulinoma cells increased the amplitude of high voltage-activated Ca(2+) currents, while treatment with IFN-gamma or TNF-alpha alone did not. Cytosolic Ca(2+) concentration ([Ca(2+)](c)) was also increased by IFN-gamma/TNF-alpha treatment. Blockade of L-type Ca(2+) channel by nifedipine abrogated death of insulinoma cells by IFN-gamma/TNF-alpha. Diazoxide that attenuates voltage-activated Ca(2+) currents inhibited MIN6N8 cell death by IFN-gamma/TNF-alpha, while glibenclamide that accentuates voltage-activated Ca(2+) currents augmented insulinoma cell death. A protein kinase C inhibitor attenuated MIN6N8 cell death and the increase in [Ca(2+)](c) by IFN-gamma/TNF-alpha. Following the increase in [Ca(2+)](c), calpain was activated, and calpain inhibitors decreased insulinoma cell death by IFN-gamma/TNF-alpha. As a downstream of calpain, calcineurin was activated and the inhibition of calcineurin activation by FK506 diminished insulinoma cell death by IFN-gamma/TNF-alpha. BAD phosphorylation was decreased by IFN-gamma/TNF-alpha because of the increased calcineurin activity, which was reversed by FK506. IFN-gamma/TNF-alpha induced cytochrome c translocation from mitochondria to cytoplasm and activation of caspase-9. Effector caspases such as caspase-3 or -7 were also activated by IFN-gamma/TNF-alpha treatment. These results indicate that IFN-gamma/TNF-alpha synergism induces pancreatic beta cell apoptosis by Ca(2+) channel activation followed by downstream intracellular events such as mitochondrial events and caspase activation and also suggest the therapeutic potential of Ca(2+) modulation in type 1 diabetes.


Subject(s)
Apoptosis , Calcium/physiology , Interferon-gamma/pharmacology , Islets of Langerhans/pathology , Tumor Necrosis Factor-alpha/pharmacology , Animals , Calcineurin/physiology , Carrier Proteins/metabolism , Caspases/metabolism , Cytochromes c/metabolism , Mice , Mice, Inbred NOD , Phosphorylation , Protein Transport , bcl-Associated Death Protein
13.
J Biol Chem ; 279(20): 20643-54, 2004 May 14.
Article in English | MEDLINE | ID: mdl-15014072

ABSTRACT

In WEHI-231, a representative immature B cell line, Ca(2+) entry is paradoxically augmented by treatment with 2-aminoethoxydiphenyl borate (2-APB), a blocker of inositol 1,4,5-trisphosphate receptor and of nonselective cation channels (Nam, J. H., Yun, S. S., Kim, T. J., Uhm, D.-Y., and Kim, S. J. (2003) FEBS Lett. 535, 113-118). The initial goal of the present study was to elucidate the effects of 2-APB on membrane currents, which revealed the presence of novel K(+) channels in WEHI-231 cells. Under whole-cell patch clamp conditions, 2-APB induced background K(+) current (I(K,bg)) and hyperpolarization in WEHI-231 cells. Lowering of intracellular MgATP also induced the I(K,bg). The I(K,bg) was blocked by micromolar concentrations of quinidine but not by tetraethylammonium. In a single channel study, two types of voltage-independent K(+) channels were found with large (346 picosiemens) and medium conductance (112 picosiemens), named BK(bg) and MK(bg), respectively. The excision of membrane patches (inside-out (i-o) patches) greatly increased the P(o) of BK(bg). In i-o patches, cytoplasmic MgATP (IC(50) = 0.18 mm) decreased the BK(bg) activity, although non-hydrolyzable adenosine 5'-(beta,gamma-imino)triphosphate had no effect. A pretreatment with Al(3+) or wortmannin (50 microm) blocked the inhibitory effects of MgATP. A direct application of phosphoinositide 4,5-bisphosphate (10 microm) inhibited the BK(bg) activity. Meanwhile, the activity of MK(bg) was unaffected by MgATP. In cell-attached conditions, the BK(bg) activity was largely increased by 2-APB. In i-o patches, however, the MgATP-induced inhibition of BK(bg) was weakly reversed by the addition of 2-APB. In summary, WEHI-231 cells express the unique background K(+) channels. The BK(bg)s are inhibited by membrane-delimited elevation of phosphoinositide 4,5-bisphosphate. The activation of BK(bg) would hyperpolarize the membrane, which augments the calcium influx in WEHI-231 cells.


Subject(s)
Adenosine Triphosphate/pharmacology , B-Lymphocytes/physiology , Potassium Channels/physiology , Aluminum/pharmacology , Androstadienes/pharmacology , Animals , B-Lymphocytes/drug effects , Boron Compounds/pharmacology , Kinetics , Mice , Patch-Clamp Techniques , Potassium Channels/drug effects , Wortmannin
14.
Pflugers Arch ; 447(4): 408-15, 2004 Jan.
Article in English | MEDLINE | ID: mdl-14652760

ABSTRACT

In this study, the short-circuit currents ( I(sc)) of electrolyte absorption and secretion in neonatal and adult rat colonic mucosa were compared and the role of Ca(2+) influx through luminal membranes examined in relation to the replenishment of intracellular Ca(2+) stores in colonic crypt cells. Neonatal tissues displayed higher amiloride-sensitive I(sc) and larger increases of electrogenic Cl(-) secretion in response to an increase in cytosolic [Ca(2+)] ([Ca(2+)](c)) or cAMP than found in adult colonic epithelium. Ca(2+)-mediated Cl(-) secretion as reflected in the I(sc) responses to carbachol ( I(sc,CCh)) showed milder "run-down" in neonates than in adult rats. We then employed the relatively stable I(sc,CCh) of the neonatal colon to investigate the polarity of Ca(2+) entry pathway after muscarinic stimulation. Repetitive stimulation with CCh under Ca(2+)-free conditions emptied the intracellular Ca(2+) stores and abolished the I(sc,CCh). Re-adding Ca(2+) to the basolateral perfusate rapidly restored I(sc,CCh) (about 71% of control in 10 min). In contrast, after re-adding Ca(2+) to the luminal perfusate only, the recovery of I(sc,CCh) took much longer and was incomplete, recovering to only 28% of control after 30 min. Recovery was accelerated by increasing [Ca(2+)] in the luminal perfusate (5 mM) and blocked by the presence of Gd(3+) (100 microM) in the luminal perfusate. The above results suggest that, in addition to the predominant role of Ca(2+) entry through the basolateral membrane, the influx of Ca(2+) through luminal membranes might also play a role in the Ca(2+) homeostasis of colonic epithelial cells.


Subject(s)
Calcium/metabolism , Cell Membrane/metabolism , Colon/metabolism , Intestinal Mucosa/metabolism , Age Factors , Amiloride/pharmacology , Animals , Animals, Newborn , Carbachol/pharmacology , Cell Polarity , Cholinergic Agonists/pharmacology , Chromans/pharmacology , Colforsin/pharmacology , Colon/anatomy & histology , Diuretics/pharmacology , Electrophysiology , Female , In Vitro Techniques , Intestinal Mucosa/cytology , Intestinal Mucosa/drug effects , Male , Potassium Channel Blockers/pharmacology , Rats , Sulfonamides/pharmacology
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