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Keratinocytes, the predominant cell type of the epidermis, migrate to reinstate the epithelial barrier during wound healing. Mechanical cues are known to regulate keratinocyte re-epithelialization and wound healing; however, the underlying molecular transducers and biophysical mechanisms remain elusive. Here, we show through molecular, cellular, and organismal studies that the mechanically activated ion channel PIEZO1 regulates keratinocyte migration and wound healing. Epidermal-specific Piezo1 knockout mice exhibited faster wound closure while gain-of-function mice displayed slower wound closure compared to littermate controls. By imaging the spatiotemporal localization dynamics of endogenous PIEZO1 channels, we find that channel enrichment at some regions of the wound edge induces a localized cellular retraction that slows keratinocyte collective migration. In migrating single keratinocytes, PIEZO1 is enriched at the rear of the cell, where maximal retraction occurs, and we find that chemical activation of PIEZO1 enhances retraction during single as well as collective migration. Our findings uncover novel molecular mechanisms underlying single and collective keratinocyte migration that may suggest a potential pharmacological target for wound treatment. More broadly, we show that nanoscale spatiotemporal dynamics of Piezo1 channels can control tissue-scale events, a finding with implications beyond wound healing to processes as diverse as development, homeostasis, disease, and repair.

Plant roots adapt to the mechanical constraints of the soil to grow and absorb water and nutrients. As in animal species, mechanosensitive ion channels in plants are proposed to transduce external mechanical forces into biological signals. However, the identity of these plant root ion channels remains unknown. Here, we show that Arabidopsis thaliana PIEZO1 (PZO1) has preserved the function of its animal relatives and acts as an ion channel. We present evidence that plant PIEZO1 is expressed in the columella and lateral root cap cells of the root tip, which are known to experience robust mechanical strain during root growth. Deleting PZO1 from the whole plant significantly reduced the ability of its roots to penetrate denser barriers compared to wild-type plants. pzo1 mutant root tips exhibited diminished calcium transients in response to mechanical stimulation, supporting a role of PZO1 in root mechanotransduction. Finally, a chimeric PZO1 channel that includes the C-terminal half of PZO1 containing the putative pore region was functional and mechanosensitive when expressed in naive mammalian cells. Collectively, our data suggest that Arabidopsis PIEZO1 plays an important role in root mechanotransduction and establish PIEZOs as physiologically relevant mechanosensitive ion channels across animal and plant kingdoms.

Abstract Aim Currently, there is no consensus on the retreatment recommendation of chronic hepatitis B (CHB) patients with viral rebound after cessation of treatment. In the search of reasonable treatment, we compared the efficacy and safety of adefovir (ADV) plus lamivudine (LAM) and LAM alone for the retreatment of patients with viral relapse but without genotypic resistance after cessation of LAM. Methods This is a prospective controlled study, and a total of 53 hepatitis B e antigen (HBeAg)-positive patients with viral rebound but without resistance were received either LAM plus ADV or LAM alone treatment. Results After 1-year treatment, more patients who received LAM plus ADV than those who received LAM alone had ALT normalization (84% versus 53.6%, P = 0.018) or HBV DNA levels below 1000 copies/mL (80% versus 42.9%, P < 0.006). Seven patients receiving LAM plus ADV had HBeAg seroconversion, as compared with 0 in patients receiving ALM alone (28% versus 0%, P = 0.003). During 1-year retreatment, five patients receiving LAM alone had virological breakthrough and all of them had LAM resistance strains (rtM204V/I), while no LAM- or ADV- associated resistance strains were detected in patients receiving LAM plus ADV. All patients receiving LAM plus ADV were well tolerated, and no serious side effects were noted. Conclusions Patients treated with LAM plus ADV exhibited significantly greater virological, biochemical and serological responses compared with LAM alone. These data suggested that combination of LAM plus ADV would be a good option for the retreatment of CHB patients with viral relapse after cessation of LAM.

Tissue acidosis and inflammatory mediators play critical roles in inflammatory pain. Extracellular acidosis activates acid-sensing ion channels (ASICs), which have emerged as key sensors for extracellular protons in the central and peripheral nervous systems and play key roles in pain sensation and transmission. Additionally, inflammatory mediators, such as serotonin (5-HT), are known to enhance pain sensation. However, functional interactions among protons, inflammatory mediators, and ASICs in pain sensation are poorly under-stood. In the present study, we show that 5-HT, a classical pro-inflammatory mediator, specifically enhances the proton-evoked sus-tained, but not transient, currents mediated by homomeric ASIC3 channels and heteromeric ASIC3/la and ASIC3/lb channels. Unexpectedly, the effect of 5-HT on ASIC3 channels does not involve activation of 5-HT receptors, but is mediated via a functional interaction between 5-HT and ASIC3 channels. We further show that the effect of 5-HT on ASIC3 channels depends on the newly identified nonproton ligand sensing domain. Finally, coapplication of 5-HT and acid significantly increased pain-related behaviors as assayed by the paw-licking test in mice, which was largely attenuated in ASIC3 knock-out mice, and inhibited by the nonselective ASIC inhibitor amiloride. Together, these data identify ASIC3 channels as an unexpected molecular target for acute actions of 5-HT in inflammatory pain sensation and reveal an important role of ASIC3 channels in regulating inflammatory pain via coincident detection of extracellular protons and inflammatory mediators. [ABSTRACT FROM AUTHOR]

Unlabelled: Neuroplastin (Nptn) is a member of the Ig superfamily and is expressed in two isoforms, Np55 and Np65. Np65 regulates synaptic transmission but the function of Np55 is unknown. In an N-ethyl-N-nitrosaurea mutagenesis screen, we have now generated a mouse line with an Nptn mutation that causes deafness. We show that Np55 is expressed in stereocilia of outer hair cells (OHCs) but not inner hair cells and affects interactions of stereocilia with the tectorial membrane. In vivo vibrometry demonstrates that cochlear amplification is absent in Nptn mutant mice, which is consistent with the failure of OHC stereocilia to maintain stable interactions with the tectorial membrane. Hair bundles show morphological defects as the mutant mice age and while mechanotransduction currents can be evoked in early postnatal hair cells, cochlea microphonics recordings indicate that mechanontransduction is affected as the mutant mice age. We thus conclude that differential splicing leads to functional diversification of Nptn, where Np55 is essential for OHC function, while Np65 is implicated in the regulation of synaptic function., Significance Statement: Amplification of input sound signals, which is needed for the auditory sense organ to detect sounds over a wide intensity range, depends on mechanical coupling of outer hair cells to the tectorial membrane. The current study shows that neuroplastin, a member of the Ig superfamily, which has previously been linked to the regulation of synaptic plasticity, is critical to maintain a stable mechanical link of outer hair cells with the tectorial membrane. In vivo recordings demonstrate that neuroplastin is essential for sound amplification and that mutation in neuroplastin leads to auditory impairment in mice., (Copyright © 2016 the authors 0270-6474/16/369201-16$15.00/0.)

Aim: To describe a method for the transjugular intrahepatic portal systemic shunt (TIPS) placement performed with the aid of contrast-enhanced computed tomography (CECT) and three-dimensional reconstructed vascular images (3D RVIs), and to assess its safety and effectiveness., Methods: Four hundred and ninety patients were treated with TIPS between January 2005 and December 2012. All patients underwent liver CECT and reconstruction of 3D RVIs of the right hepatic vein to portal vein (PV) prior to the operation. The 3D RVIs were carefully reviewed to plan the puncture path from the start to target points for needle pass through the PV in the TIPS procedure., Results: The improved TIPS procedure was successful in 483 (98.6%) of the 490 patients. The number of punctures attempted was one in 294 (60%) patients, 2 to 3 in 147 (30%) patients, 4 to 6 in 25 (5.1%) patients and more than 6 in 17 (3.5%) patients. Seven patients failed. Of the 490 patients, 12 had punctures into the artery, 15 into the bile duct, eight into the gallbladder, and 18 through the liver capsule. Analysis of the portograms from the 483 successful cases indicated that the puncture points were all located distally to the PV bifurcation on anteroposterior images, while the points were located proximally to the bifurcation in the three cases with intraabdominal bleeding. The complications included three cases of bleeding, of whom one died and two needed surgery., Conclusion: Use of CECT and 3D RVIs to plan the puncture path for TIPS procedure is safe, simple and effective for clinical use.

Aim: To determine the clinical effects and complications of transjugular intrahepatic portosystemic shunt (TIPS) for portal hypertension due to cirrhosis., Methods: Two hundred and eighty patients with portal hypertension due to cirrhosis who underwent TIPS were retrospectively evaluated. Portal trunk pressure was measured before and after surgery. The changes in hemodynamics and the condition of the stent were assessed by ultrasound and the esophageal and fundic veins observed endoscopically., Results: The success rate of TIPS was 99.3%. The portal trunk pressure was 26.8 ± 3.6 cmH2O after surgery and 46.5 ± 3.4 cmH2O before surgery (P < 0.01). The velocity of blood flow in the portal vein increased. The internal diameters of the portal and splenic veins were reduced. The short-term hemostasis rate was 100%. Esophageal varices disappeared completely in 68% of patients and were obviously reduced in 32%. Varices of the stomach fundus disappeared completely in 80% and were obviously reduced in 20% of patients. Ascites disappeared in 62%, were markedly reduced in 24%, but were still apparent in 14% of patients. The total effective rate of ascites reduction was 86%. Hydrothorax completely disappeared in 100% of patients. The incidence of post-operative stent stenosis was 24% at 12 mo and 34% at 24 mo. The incidence of post-operative hepatic encephalopathy was 12% at 3 mo, 17% at 6 mo and 19% at 12 mo. The incidence of post-operative recurrent hemorrhage was 9% at 12 mo, 19% at 24 mo and 35% at 36 mo. The cumulative survival rate was 86% at 12 mo, 81% at 24 mo, 75% at 36 mo, 57% at 48 mo and 45% at 60 mo., Conclusion: TIPS can effectively lower portal hypertension due to cirrhosis. It is significantly effective for hemorrhage of the digestive tract due to rupture of esophageal and fundic veins and for ascites and hydrothorax caused by portal hypertension.

Acid-sensing ion channels (ASICs) are proton-gated cation channels widely expressed in the peripheral and CNSs, which critically contribute to a variety of pathophysiological conditions that involve tissue acidosis, such as ischemic stroke and epileptic seizures. However, the trafficking mechanisms of ASICs and the related proteins remain largely unknown. Here, we demonstrate that ASIC1a, the main ASIC subunit in the brain, undergoes constitutive endocytosis in a clathrin- and dynamin-dependent manner in both mouse cortical neurons and heterologous cell cultures. The endocytosis of ASIC1a was inhibited by either the small molecular inhibitor tyrphostin A23 or knockdown of the core subunit of adaptor protein 2 (AP2) μ2 using RNA interference, supporting a clathrin-dependent endocytosis of ASIC1a. In addition, the internalization of ASIC1a was blocked by dominant-negative dynamin1 mutation K44A and the small molecular inhibitor dynasore, suggesting that it is also dynamin-dependent. We show that the membrane-proximal residues (465)LCRRG(469) at the cytoplasmic C terminus of ASIC1a are critical for interaction with the endogenous adaptor protein complex and inhibition of ASIC1a internalization strongly exacerbated acidosis-induced death of cortical neurons from wild-type but not ASIC1a knock-out mice. Together, these results reveal the molecular mechanism of ASIC1a internalization and suggest the importance of endocytic pathway in functional regulation of ASIC1a channels as well as neuronal damages mediated by these channels during neurodegeneration.

Tissue acidosis and inflammatory mediators play critical roles in inflammatory pain. Extracellular acidosis activates acid-sensing ion channels (ASICs), which have emerged as key sensors for extracellular protons in the central and peripheral nervous systems and play key roles in pain sensation and transmission. Additionally, inflammatory mediators, such as serotonin (5-HT), are known to enhance pain sensation. However, functional interactions among protons, inflammatory mediators, and ASICs in pain sensation are poorly understood. In the present study, we show that 5-HT, a classical pro-inflammatory mediator, specifically enhances the proton-evoked sustained, but not transient, currents mediated by homomeric ASIC3 channels and heteromeric ASIC3/1a and ASIC3/1b channels. Unexpectedly, the effect of 5-HT on ASIC3 channels does not involve activation of 5-HT receptors, but is mediated via a functional interaction between 5-HT and ASIC3 channels. We further show that the effect of 5-HT on ASIC3 channels depends on the newly identified nonproton ligand sensing domain. Finally, coapplication of 5-HT and acid significantly increased pain-related behaviors as assayed by the paw-licking test in mice, which was largely attenuated in ASIC3 knock-out mice, and inhibited by the nonselective ASIC inhibitor amiloride. Together, these data identify ASIC3 channels as an unexpected molecular target for acute actions of 5-HT in inflammatory pain sensation and reveal an important role of ASIC3 channels in regulating inflammatory pain via coincident detection of extracellular protons and inflammatory mediators.

Central neural plasticity plays a key role in pain hypersensitivity. This process is modulated by brain-derived neurotrophic factor (BDNF) and also involves the type 1a acid-sensing ion channel (ASIC1a). However, the interactions between the BDNF receptor, tropomyosin-related kinase B (TrkB), and ASIC1a are unclear. Here, we show that deletion of ASIC1 gene suppressed the sustained mechanical hyperalgesia induced by intrathecal BDNF application in mice. In both rat spinal dorsal horn neurons and heterologous cell cultures, the BDNF/TrkB pathway enhanced ASIC1a currents via phosphoinositide 3-kinase (PI3K)-protein kinase B (PKB/Akt) cascade and phosphorylation of cytoplasmic residue Ser-25 of ASIC1a, resulting in enhanced forward trafficking and increased surface expression. Moreover, in both rats and mice, this enhanced ASIC1a activity was required for BDNF-mediated hypersensitivity of spinal dorsal horn nociceptive neurons and central mechanical hyperalgesia, a process that was abolished by intrathecal application of a peptide representing the N-terminal region of ASIC1a encompassing Ser-25. Thus, our results reveal a novel mechanism underlying central sensitization and pain hypersensitivity, and reinforce the critical role of ASIC1a channels in these processes.

Background: The pathogenesis of hepatic fibrosis and cirrhosis is still not fully understood. The extracellular signal-regulated kinase (ERK) pathway is involved in the regulation of cell proliferation and differentiation. The aim of this study was to investigate the effects of PD98059, a specific inhibitor of ERK, on the cell cycle, cell proliferation, secretion of type I collagen and expression of cyclin D1 mRNA, CDK4 mRNA and transforming growth factor-beta1 (TGF-beta1) mRNA in rat hepatic stellate cells (HSCs) stimulated by acetaldehyde., Methods: Rat HSCs stimulated by acetaldehyde were incubated with PD98059 at different concentrations. The cell cycle was analysed by flow cytometry. Cell proliferation was assessed by the methyl thiazolyl tetrazolium colorimetric assay. The mRNA expression of cyclin D1, CDK4 and TGF-beta1 was examined using the reverse transcriptase-polymerase chain reaction. Type I collagen in the culture medium was detected by enzyme-linked immunosorbent assay., Results: 20, 50 and 100 micromol/L PD98059 significantly inhibited the proliferation and provoked a G0/G1-phase arrest of acetaldehyde-induced HSCs in a dose-dependent manner. The secretion of type I collagen and the expression of cyclin D1, CDK4 and TGF-beta1 mRNA in acetaldehyde-induced HSCs were markedly inhibited by 50 and 100 micromol/L PD98059, respectively., Conclusions: The ERK pathway regulates the cell proliferation, secretion of type I collagen and the expression of TGF-beta1 mRNA in rat HSCs stimulated by acetaldehyde, which is likely related to its regulative effect on the cell cycle.

Aim: To explore the anti-fibrotic effect of a traditional Chinese medicine, compound rhodiola sachalinensis A Bor on CCl(4)-induced liver fibrosis in rats and its probable molecular mechanisms., Methods: Ninety healthy male SD rats were randomly divided into three groups: normal group (n=10), treatment group of compound rhodiola sachalinensis A Bor (n=40) and CCl(4)-induced model group (n=40). The liver fibrosis was induced by CCl(4) subcutaneous injection. Treatment group was administered with compound rhodiola sachalinensis A Bor (0.5 g/kg) once a day at the same time. Then the activities of several serum fibrosis-associated enzymes: alanine aminotransferase (ALT), aspartate aminotransferase (AST), N-acetyl-beta-D-glucosaminidase (beta-NAG) and the levels of serum procollagen III (PCIII), collagen IV (CIV), hyaluronic acid (HA) were assayed. The histopathological changes were observed with HE, VG and Masson stain. The expression of TGF-beta1 mRNA, alpha1 (I) mRNA and Na(+)/Ca(2+) exchanger (NCX) mRNA was detected by reverse transcription polymerase chain reaction (RT-PCR) in situ., Results: Compound rhodiola sachalinensis A Bor significantly reduced serum activities of ALT, AST, beta-NAG and decreased the levels of PCIII, CIV, HA, improved the liver histopathological changes, inhibited the expression of TGF-beta1 mRNA, alpha (I) mRNA and Na(+)/Ca(2+) exchanger mRNA in rats., Conclusion: Compound rhodiola sachalinensis A Bor can intervene in CCl(4)-induced liver fibrosis in rats, in which potential mechanisms may be decreasing the production of TGF-beta1, reducing the production of collagen, preventing the activation of hepatic stellate cell (HSC) and inhibiting the expression of TGF-beta1 mRNA, alpha1(I) mRNA and Na(+)/Ca(2+) exchanger mRNA.