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ABSTRACT: The aim of this study is to observe the tonal acquisition in a pair of fraternal twins from 1 to 3 years old, making a comparison between a child with cochlear implant (Child A) and a child with normal hearing (Child B). Spontaneous data were transcribed and later tone duration and tonal slope were measured by Praat. Four main tones in Mandarin were analyzed: high-level, high-rising, high-falling, and low-falling tones. Major findings are: 1) Tone duration of Child B is longer than that of Child A by 1.2-1.7 times. The average of tone duration in Child A is 250ms-260ms; 2) In Child A, high-level tones show the shortest duration among the four main tones, and high-rising tones are the longest; 3)Tonal slope of Child A is flatter than in Child B. The absolute value of tonal slope is higher in Child B; 4) Children control high-level tone the best, followed by high-rising, then high-falling, and low-falling the last.
The Journal of the Acoustical Society of America 04/2012; 131(4):3274. · 1.55 Impact Factor
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ABSTRACT: Plectranthus amboinicus (Lour.) Spreng. is a native Labiatae plant of Taiwan. The plants are commonly used in Chinese folk medicine for the treatment of cough, fever, sore throats, mumps, and mosquito bite. The aim of this study was to investigate the analgesic and antiinflammatory properties of the aqueous extract from Plectranthus amboinicus (PA) in vivo and in vitro. PA inhibited pain induced by acetic acid and formalin, and inflammation induced by carrageenan. The anti-inflammatory effect of PA was related to modulating antioxidant enzymes' activities in the liver and decreasing the Malondialdehyde (MDA) level and the production of tumor necrosis factor alpha (TNF-α), and cyclooxygenase2 (COX-2) in edema-paw tissue in mice. In vitro studies show that PA inhibited the proinflammatory mediators in RAW 264.7 cells stimulated with lipopolysaccharide (LPS). PA blocked the degradation of IκB-α and nuclear translocation of NF-κB p65 subunit. Finally, the amount of carvacrol in the aqueous extract of PA was 1.88 mg/g extract. Our findings suggest that PA has analgesic and anti-inflammatory activities. These effects were mediated by inhibiting the proinflammatory mediators through blocking NF-κB activation. Meanwhile, the effects observed in this study provide evidence for folkloric uses of Plectranthus amboinicus (Lour.) Spreng. in relieving pain and inflammation.
Evidence-based Complementary and Alternative Medicine 01/2012; 2012:508137. · 4.77 Impact Factor
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ABSTRACT: Matriptase proteolytic activity must be tightly controlled for normal placental development, epidermal function, and epithelial integrity. Although hepatocyte growth factor activator inhibitor-1 (HAI-1) represents the predominant endogenous inhibitor for matriptase and the protein molar ratio of HAI-1 to matriptase is determined to be >10 in epithelial cells and the majority of carcinoma cells, an inverse HAI-1-to-matriptase ratio is seen in some ovarian and hematopoietic cancer cells. In the current study, cells with insufficient HAI-1 are investigated for the mechanisms through which the activity of matriptase is regulated. When matriptase activation is robustly induced in these cells, activated matriptase rapidly forms two complexes of 100- and 140-kDa in addition to the canonical 120-kDa matriptase-HAI-1 complex already described. Both 100- and 140-kDa complexes contain two-chain, cleaved matriptase but are devoid of gelatinolytic activity. Further biochemical characterization shows that the 140-kDa complex is a matriptase homodimer and that the 100-kDa complexes appear to contain reversible, tight binding serine protease inhibitor(s). The formation of the 140-kDa matriptase dimer is strongly associated with matriptase activation, and its levels are inversely correlated with the ratio of HAI-1 to matriptase. Given these observations and the likelihood that autoactivation requires the interaction of two matriptase molecules, it seems plausible that this activated matriptase homodimer may represent a matriptase autoactivation intermediate and that its accumulation may serve as a mechanism to control matriptase activity when protease inhibitor levels are limiting. These data suggest that matriptase activity can be rapidly inhibited by HAI-1 and other HAI-1-like protease inhibitors and "locked" in an inactive autoactivation intermediate, all of which places matriptase under very tight control.
AJP Cell Physiology 01/2012; 302(2):C453-62. · 3.54 Impact Factor
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Zhenghong Xu, Ya-Wen Chen,
Aruna Battu,
Paul Wilder,
David Weber,
Wenbo Yu,
Alexander D Mackerell,
Li-Mei Chen,
Karl X Chai,
Michael D Johnson,
Chen-Yong Lin
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ABSTRACT: Membrane-associated serine protease matriptase has been implicated in human diseases and might be a drug target. In the present study, a novel class of matriptase inhibitors targeting zymogen activation is developed by a combination of the screening of compound library using a cell-based matriptase activation assay and a computer-aided search of commercially available analogues of a selected compound. Four structurally related compounds are identified that can inhibit matriptase activation with IC(50) at low micromolar concentration in both intact-cell and cell-free systems, suggesting that these inhibitors target the matriptase autoactivation machinery rather than the intracellular signaling pathways. These activation inhibitors can also inhibit prostasin activation, a downstream event that occurs in lockstep with matriptase activation. In contrast, the matriptase catalytic inhibitor CVS-3983 at a concentration 300-fold higher than its K(i) fails to inhibit activation of either protease. Our results suggest that inhibiting matriptase activation is an efficient way to control matriptase function.
Journal of Medicinal Chemistry 10/2011; 54(21):7567-78. · 4.80 Impact Factor
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ABSTRACT: Antithrombin, a major anticoagulant, is robustly transported into extravascular compartments where its target proteases are largely unknown. This serpin was previously detected in human milk as complexes with matriptase, a membrane-bound serine protease broadly expressed in epithelial and carcinoma cells, and under tight regulation by hepatocyte growth factor activator inhibitor (HAI)-1, a transmembrane Kunitz-type serine protease inhibitor that forms heat-sensitive complexes with active matriptase. In the current study, we detect, in addition to matriptase-HAI-1 complexes, heat-resistant matriptase complexes generated by nontransformed mammary, prostate, and epidermal epithelial cells that we show to be matriptase-antithrombin complexes. These findings suggest that in addition to HAI-1, interstitial antithrombin participates in the regulation of matriptase activity in epithelial cells. This physiological mechanism appears, however, to largely be lost in cancer cells since matriptase-antithrombin complexes were not detected in all but two of a panel of seven breast, prostate, and ovarian cancer cell lines. Using purified active matriptase, we further characterize the formation of matriptase-antithrombin complex and show that heparin can significantly potentiate the inhibitory potency of antithrombin against matriptase. Second-order rate constants for the inhibition were determined to be 3.9 × 10(3) M(-1)s(-1) in the absence of heparin and 1.2 × 10(5) M(-1)s(-1) in the presence of heparin, a 30-fold increase, consistent with the established role of heparin in activating antithrombin function. Taken together these data suggest that normal epithelial cells employ a dual mechanism involving HAI-1 and antithrombin to control matriptase and that the antithrombin-based mechanism appears lost in the majority of carcinoma cells.
AJP Cell Physiology 07/2011; 301(5):C1093-103. · 3.54 Impact Factor
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Cheng-Jueng Chen,
Bai-Yao Wu,
Pai-In Tsao,
Chi-Yung Chen,
Mei-Hsuan Wu,
Yee Lam E Chan,
Herng-Sheng Lee,
Michael D Johnson,
Richard L Eckert, Ya-Wen Chen,
Fengpai Chou,
Jehng-Kang Wang,
Chen-Yong Lin
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ABSTRACT: Matriptase, a type 2 transmembrane serine protease, and its inhibitor hepatocyte growth factor activator inhibitor (HAI)-1 are required for normal epidermal barrier function, and matriptase activity is tightly regulated during this process. We therefore hypothesized that this protease system might be deregulated in skin disease. To test this, we examined the level and activation state of matriptase in examples of 23 human skin disorders. We first examined matriptase and HAI-1 protein distribution in normal epidermis. Matriptase was detected at high levels at cell-cell junctions in the basal layer and spinous layers but was present at minimal levels in the granular layer. HAI-1 was distributed in a similar pattern, except that high-level expression was retained in the granular layer. This pattern of expression was retained in most skin disorders. We next examined the distribution of activated matriptase. Although activated matriptase is not detected in normal epidermis, a dramatic increase is seen in keratinocytes at the site of inflammation in 16 different skin diseases. To gain further evidence that activation is associated with inflammatory stimuli, we challenged HaCaT cells with acidic pH or H(2)O(2) and observed matriptase activation. These findings suggest that inflammation-associated reactive oxygen species and tissue acidity may enhance matriptase activation in some skin diseases.
AJP Cell Physiology 12/2010; 300(3):C406-15. · 3.54 Impact Factor
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ABSTRACT: Type I transglutaminase (TG1) is an enzyme that is responsible for assembly of the keratinocyte cornified envelope. Although TG1 mutation is an underlying cause of autosomal recessive congenital ichthyosis, a debilitating skin disease, the pathogenic mechanism is not completely understood. In the present study we show that TG1 is an endoplasmic reticulum (ER) membrane-associated protein that is trafficked through the ER for ultimate delivery to the plasma membrane. Mutation severely attenuates this processing and a catalytically inactive point mutant, TG1-FLAG(C377A), accumulates in the endoplasmic reticulum and in aggresome-like structures where it is ubiquitinylated. This accumulation results from protein misfolding, as treatment with a chemical chaperone permits it to exit the endoplasmic reticulum and travel to the plasma membrane. ER accumulation is also observed for ichthyosis-associated TG1 mutants. Our findings suggest that misfolding of TG1 mutants leads to ubiquitinylation and accumulation in the ER and aggresomes, and that abnormal intracellular processing of TG1 mutants may be an underlying cause of ichthyosis.
Journal of Biological Chemistry 10/2010; 285(41):31634-46. · 4.77 Impact Factor
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ABSTRACT: Matriptase, a membrane-tethered serine protease, plays essential roles in epidermal differentiation and barrier function, largely mediated via its activation of prostasin, a glycosylphosphatidylinositol-anchored serine protease. Matriptase activity is tightly regulated by its inhibitor hepatocyte growth factor activator inhibitor-1 (HAI-1) such that free active matriptase is only briefly available to act on its substrates. In the current study we provide evidence for how matriptase activates prostasin under this tight control by HAI-1. When primary human keratinocytes are induced to differentiate in a skin organotypic culture model, both matriptase and prostasin are constitutively activated and then inhibited by HAI-1. These processes also occur in HaCaT human keratinocytes when matriptase activation is induced by exposure of the cells to a pH 6.0 buffer. Using this acid-inducible activation system we demonstrate that prostatin activation is suppressed by matriptase knockdown and by blocking matriptase activation with sodium chloride, suggesting that prostatin activation is dependent on matriptase in this system. Kinetics studies further reveal that the timing of autoactivation of matriptase, prostasin activation, and inhibition of both enzymes by HAI-1 binding are closely correlated. These data suggest that, during epidermal differentiation, the matriptase-prostasin proteolytic cascade is tightly regulated by two mechanisms: 1) prostasin activation temporally coupled to matriptase autoactivation and 2) HAI-1 rapidly inhibiting not only active matriptase but also active prostasin, resulting in an extremely brief window of opportunity for both active matriptase and active prostasin to act on their substrates.
Journal of Biological Chemistry 10/2010; 285(41):31755-62. · 4.77 Impact Factor
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Ya-Wen Chen,
Ming-Shyue Lee,
Amanda Lucht,
Feng-Pai Chou,
Wei Huang,
Thomas C Havighurst,
KyungMann Kim,
Jehng-Kang Wang,
Toni M Antalis,
Michael D Johnson,
Chen-Yong Lin
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ABSTRACT: TMPRSS2, a type II transmembrane serine protease, is highly expressed by the epithelium of the human prostate gland. To explore the regulation and function of TMPRSS2 in the prostate, a panel of monoclonal antibodies with high sensitivity and specificity were generated. Immunodetection showed TMPRSS2 on the apical plasma membrane of the prostate luminal cells and demonstrated its release into semen as a component of prostasomes, organelle-like vesicles that may facilitate sperm function and enhance male reproduction. In prostate cancer cells, TMPRSS2 expression was increased and the protein mislocalized over the entire tumor cell membrane. In both LNCaP prostate cancer cells and human semen, TMPRSS2 protein was detected predominantly as inactive zymogen forms as part of an array of multiple noncovalent and disulfide-linked complexes, suggesting that TMPRSS2 activity may be regulated by unconventional mechanisms. Our data suggested that TMPRSS2, an apical surface serine protease, may have a normal role in male reproduction as a component of prostasomes. The aberrant cellular localization, and increased expression of the protease seen in cancer, may contribute to prostate tumorigenesis by providing access of the enzyme to nonphysiological substrates and binding-proteins.
American Journal Of Pathology 04/2010; 176(6):2986-96. · 4.89 Impact Factor
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ABSTRACT: Matriptase, a transmembrane serine protease, is broadly expressed by, and crucial for the integrity of, the epithelium. Matriptase is synthesized as a zymogen and undergoes autoactivation to become an active protease that is immediately inhibited by, and forms complexes with, hepatocyte growth factor activator inhibitor (HAI-1). To investigate where matriptase is activated and how it is secreted in vivo, we determined the expression and activation status of matriptase in seminal fluid and urine and the distribution and subcellular localization of the protease in the prostate and kidney. The in vivo studies revealed that while the latent matriptase is localized at the basolateral surface of the ductal epithelial cells of both organs, only matriptase-HAI-1 complexes and not latent matriptase are detected in the body fluids, suggesting that activation, inhibition, and transcytosis of matriptase would have to occur for the secretion of matriptase. These complicated processes involved in the in vivo secretion were also observed in polarized Caco-2 intestinal epithelial cells. The cells target latent matriptase to the basolateral plasma membrane where activation, inhibition, and secretion of matriptase appear to take place. However, a proportion of matriptase-HAI-1 complexes, but not the latent matriptase, appears to undergo transcytosis to the apical plasma membrane for secretion. When epithelial cells lose their polarity, they secrete both latent and activated matriptase. Although most epithelial cells retain very low levels of matriptase-HAI-1 complex by rapidly secreting the complex, gastric chief cells may activate matriptase and store matriptase-HAI-1 complexes in the pepsinogen-secretory granules, suggesting an intracellular activation and regulated secretion in these cells. Taken together, while zymogen activation and closely coupled HAI-1-mediated inhibition are common features for matriptase regulation, the cellular location of matriptase activation and inhibition, and the secretory route for matriptase-HAI-1 complex may vary along with the functional divergence of different epithelial cells.
AJP Cell Physiology 07/2009; 297(2):C459-70. · 3.54 Impact Factor
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ABSTRACT: Matriptase is a member of an expanding group of type II transmembrane serine proteases. Recently, much has been learned about the biochemistry, cellular biology, normal tissue physiology, and human pathology of this protease, and of its inhibitor, termed the hepatocyte growth factor inhibitor-1 (HAI-1). This review examines the recent literature that has characterized the regulation of matriptase and HAI-1 with an emphasis on the molecular mechanisms governing its zymogen activation, inhibition by HAI-1, and ectodomain shedding.
Frontiers in Bioscience 02/2008; 13:621-35. · 3.52 Impact Factor
