An RNA aptamer containing two binding sites of HIV Tat exhibits extremely high affinity to Tat. We have determined the structure of the aptamer complexed with an RNA-binding peptide of Tat. The analysis was made feasible by the use of several peptides in which a single arginine residue was specifically 13C, 15N-labeled. Residue specific labeling of the peptide enhanced the identification of intermolecular contacts, which are otherwise hard to identify due to spectral overlapping. The structure of the complex has revealed the origin of the high affinity of the aptamer to Tat.
Background The purpose of this study was to assess the candidates suitable for cardiac resynchronization therapy (CRT) and to examine the significance of the QRS duration in Japanese patients with idiopathic dilated cardiomyopathy (DCM). Methods and Results The study population consisted of 357 patients. The selection criteria for candidates suitable for CRT were QRS duration =130 ms, left ventricular ejection fraction (LVEF) =35% and New York Heart Association (NYHA) functional class III or IV by ACC/AHA/NASPE 2002 guidelines. We divided the study population into 2 groups: group A with a QRS duration <130 ms, and group B with a QRS duration =130 ms. In 25 of the 375 patients (7.0%), all the criteria were fulfilled. Group B had a significantly larger left ventricular diameter end-diastole and end-systole than group A (P<0.0001). Group B had a lower LVEF (P<0.0001). There was a fair inverse correlation (r=-0.58, P<0.0001) between the length of the QRS duration and LVEF. Conclusion Approximately 7% of the Japanese patients with DCM are CRT candidates. In the present study, we found that prolonged QRS duration was associated with poor systolic function. (Circ J 2004; 68: 1104 - 1109)
The growing interest in skin lightening has recently renewed attention on the esthetic applications of Chinese herbal medicine. Although Scutellaria baicalensis Georgi is used for antipyretic and antiinflammatory purposes, its whitening effect remains unclear. This study reports three major findings: (1) S. baicalensis has a potent inhibitory effect on melanogenesis; (2) wogonin and its glycoside are the active components of S. baicalensis; and (3) O-methylated flavones from S. baicalensis, such as wogonin, inhibit intracellular melanosome transport. Using a melanin quantification assay, we showed that S. baicalensis potently inhibits melanogenesis in B16F10 cells. Componential analyses revealed that the main components of S. baicalensis are baicalin, wogonoside, baicalein, wogonin, and oroxylin A. Among these five flavones, wogonin and wogonoside consistently inhibited melanogenesis in both B16F10 melanoma cells and primary melanocytes. Wogonin exhibited the strongest inhibition of melanin production and markedly lightened the color of skin equivalents. We identified microphthalmia-associated transcription factor and tyrosinase-related proteins as potential targets of wogonin- and wogonoside-induced melanogenesis suppression. In culture, we found that the melanosomes in wogonin-treated B16F10 cells were localized to the perinuclear region. Immunoblotting analyses revealed that wogonin significantly reduced in melanophilin protein, which is required for actin-based melanosome transport. Other actin-based melanosome transport-related molecules, i.e., Rab27A and myosin Va, were not affected by wogonin. Cotreatment with MG132 blocked the wogonin-induced decrease in melanophilin, suggesting that wogonin promotes the proteolytic degradation of melanophilin via the calpain/proteasomal pathway. We determined that the structural specificities of the mono-O-methyl group in the flavone A-ring and the aglycone form were responsible for reducing melanosome transport. Furthermore, wogonin and two wogonin analogs, mono-O-methyl flavones, strongly suppressed melanosome transport. Our findings suggest the applicability of S. baicalensis in the esthetic field. Thus, we propose a novel pharmacologic approach for the treatment of hyperpigmentation.
Scope Nonalcoholic fatty liver disease (NAFLD) has emerged as the most common chronic liver disease worldwide, defined by hepatic over‐accumulation of lipids without significant ethanol consumption. Pharmacological or bioactive food ingredients that suppress hepatic lipid accumulation through AMP‐activated protein kinase (AMPK) signaling, which plays a critical role in the regulation of lipid metabolism, are searched. Methods and results It is found that tomatidine, the aglycone of α‐tomatine abundant in green tomatoes, significantly inhibits palmitate‐provoked lipid accumulation and stimulates phosphorylation of AMPK and acetyl‐CoA carboxylase 1 (ACC1) in human HepG2 hepatocytes. The results also indicate that tomatidine can enhance triglyceride turnover and decline in lipogenesis by upregulating adipose triglyceride lipase (ATGL) and downregulating fatty acid synthase (FAS) via the AMPK signaling‐dependent regulation of transcription factors, element‐binding protein‐1c (SREBP‐1c) and forkhead box protein O1 (FoxO1). Furthermore, mechanistic studies demonstrate that tomatidine‐stimulated AMPK phosphorylation is due to CaMKKβ activation in response to an increase in intracellular Ca 2+ concentration. Finally, it is discovered that tomatidine functions as an agonist for vitamin D receptor to elicit AMPK‐dependent suppression of lipid accumulation. Conclusion The in vitro study suggests the potential efficacy of tomatidine as a preventive and therapeutic treatment in obesity‐related fatty liver diseases.
Peptide transporter 2 (PEPT2) is a member of the proton-coupled oligopeptide transporter family, which mediates the cellular uptake of oligopeptides and peptide-like drugs. Although PEPT2 is expressed in many tissues, its expression in epidermal keratinocytes remains unclear. We investigated PEPT2 expression profile and functional activity in keratinocytes. We confirmed PEPT2 mRNA expression in three keratinocyte lines (normal human epidermal keratinocytes (NHEKs), immortalized keratinocytes, and malignant keratinocytes) by reverse transcription-polymerase chain reaction (RT-PCR) and quantitative real-time RT-PCR. In contrast to PEPT1, PEPT2 expression in the three keratinocytes was similar or higher than that in HepG2 cells, used as PEPT2-positive cells. Immunolocalization analysis using human skin showed epidermal PEPT2 localization. We studied keratinocyte transport function by measuring the oligopeptide content using liquid chromatography/tandem mass spectrometry. Glycylsarcosine uptake in NHEKs was pH-dependent, suggesting that keratinocytes could absorb small peptides in the presence of an inward H(+) gradient. We also performed a skin-permeability test of several oligopeptides using skin substitute, suggesting that di- and tripeptides pass actively through the epidermis. In conclusion, PEPT2 is expressed in keratinocytes and involved in skin oligopeptide uptake.
'/%3e%3c/defs%3e%3cpath fill='%23012169' d='M0 0h10080v5040H0z'/%3e%3cpath stroke='%23fff' stroke-width='.6' d='m0 0 6 3m0-3L0 3' clip-path='url(%23b)' transform='scale(840)'/%3e%3cpath stroke='%23e4002b' stroke-width='.4' d='m0 0 6 3m0-3L0 3' clip-path='url(%23c)' transform='scale(840)'/%3e%3cpath stroke='%23fff' stroke-width='840' d='M2520 0v2520M0 1260h5040'/%3e%3cpath stroke='%23e4002b' stroke-width='504' d='M2520 0v2520M0 1260h5040'/%3e%3cg fill='%23fff'%3e%3cuse xlink:href='%23d' x='2520' y='3780'/%3e%3cuse xlink:href='%23a' x='7560' y='4200'/%3e%3cuse xlink:href='%23a' x='6300' y='2205'/%3e%3cuse xlink:href='%23a' x='7560' y='840'/%3e%3cuse xlink:href='%23a' x='8680' y='1869'/%3e%3cuse xlink:href='%23e' x='8064' y='2730'/%3e%3c/g%3e%3c/svg%3e)