Changes in condylar position during orthodontic treatment depending on the amount of incisor retraction: a cone-beam computed tomography study.

OBJECTIVES: Orthodontic treatment may be associated with temporomandibular disorders through changes in the condylar position. This study aimed to evaluate changes in the condylar position among different amounts of maxillary incisor retraction during orthodontic treatment using cone-beam computed tomography images. MATERIALS AND METHODS: Fifty-four participants were enrolled and divided into minimal (n = 14), moderate (n = 20), and maximal (n = 20) retraction groups based on the amount of incisor retraction (< 1, 1-6, and > 6 mm, respectively). Changes in condylar position before (T0) and after (T1) orthodontic treatment were assessed for the superior, anterior, posterior, and medial joint spaces (SJS, AJS, PJS, and MJS, respectively). Changes in joint spaces were compared between T0 and T1 in each group using paired t-tests and among the three groups using analysis of variance. RESULTS: Anterior movement of the condyle was observed in the maximal retraction group with a 0.2 mm decrease in ΔAJS and a 0.2 mm increase in ΔPJS, significantly greater than those in the minimal retraction group. The AJS and PJS showed statistically significant differences between T0 and T1 (P < 0.05) in the maximal retraction group. CONCLUSIONS: The condyle may show a statistically significant but clinically insignificant forward movement in the maximal incisor retraction group, whereas it was relatively stable in the minimal and moderate incisor retraction groups. CLINICAL RELEVANCE: More attention should be paid to the signs and symptoms of the condyle in patients with excessive incisor retraction during orthodontic treatment.

Posttreatment stability of an anterior open-bite by molar intrusion compared with 2-jaw surgery - a retrospective study.

OBJECTIVES: This study aimed to compare post-treatment stability in patients with anterior open-bite (AOB) between those treated surgically (orthognathic 2-jaw surgery) and non-surgically (molar intrusion using orthodontic miniscrews). MATERIALS AND METHODS: All subjects had initial overbite (OB) < -1 mm and lateral cephalograms taken before treatment (T0), immediately after AOB correction (T1), after orthodontic treatment (T2), and at least 1 year after treatment (T3). The non-surgical group was enrolled retrospectively; then, the surgical group was matched by OB, sex, and age to the non-surgical group (n = 21 each). Changes in cephalometric measurements during treatment (T1-T0), finishing (T2-T1), and retention (T3-T2) periods were compared between two groups. RESULTS: OB increased by 4.5-5.1 mm during the treatment period with 3.3 mm upward movement of the maxillary first molar (U6) in both groups. Changes in OB were not significantly different between the groups: 0.5-0.9 mm increase during the finishing period but 1.0 mm decrease during the retention period (P > 0.05). U6 moved 0.5 mm downward in non-surgical group and 0.1 mm upward in the surgical group during the finishing period, and 1.0 mm and 0.4 mm downward in the non-surgical and surgical groups, respectively, during the retention period. CONCLUSIONS: Post-treatment stability of AOB was similar for surgical and non-surgical methods (76.8 - 78.7%), although U6 moved more downward in the non-surgical group than in the surgical group. CLINICAL RELEVANCE: AOB without severe skeletal deformity can be treated by either molar intrusion or orthognathic surgery with similar treatment outcome and stability.

SWNT Anchored with Carboxylated Polythiophene "Links" on High-Capacity Li-Ion Battery Anode Materials.

Conjugated polymers possessing polar functionalities were shown to effectively anchor single-walled carbon nanotubes (SWNTs) to the surface of high-capacity anode materials and enable the formation of electrical networks. Specifically, poly[3-(potassium-4-butanoate) thiophene] (PPBT) served as a bridge between SWNT networks and various anode materials, including monodispersed Fe3O4 spheres (sFe3O4) and silicon nanoparticles (Si NPs). The PPBT π-conjugated backbone and carboxylate (COO-) substituted alkyl side chains, respectively, attracted the SWNT π-electron surface and chemically interacted with active material surface hydroxyl (-OH) species to form a carboxylate bond. Beneficially, this architecture effectively captured cracked/pulverized particles that typically form as a result of repeated active material volume changes that occur during charging and discharging. Thus, changes in electrode thickness were suppressed substantially, stable SEI layers were formed, electrode resistance was reduced, and enhanced electrode kinetics was observed. Together, these factors led to excellent electrochemical performance.

A High Aspect Ratio Serpentine Structure for Use As a Strain-Insensitive, Stretchable Transparent Conductor.

The development of strain-insensitive stretchable transparent conductors (TCs) is essential for manufacturing stretchable electronics. Despite recent progress, achieving a high optoelectronic performance under applied strain of 50% continues to present a significant challenge in this research field. Herein, an ultratall and ultrathin high aspect ratio serpentine metal structure is described that exhibits a remarkable stretching ability (the resistance remains constant under applied strain of 100%) and simultaneously provides an excellent transparent conducting performance (with a sheet resistance of 7.6 Ω î¨-1 and a transmittance of 90.5%). It is demonstrated that the highly stretchable transparent conducting properties can be attributed to the high aspect ratio feature. A high aspect ratio (aspect ratio of 17-367) structure permits facile deformation of the serpentine structure with in-plane motion, leading to a high stretching ability. In addition, this structural feature avoids the classic tradeoff between optical transmittance and electrical conductance, providing a high electrical conductance without decreasing the optical transmittance. The practical utility of these devices is tested by using these TCs as stretchable interconnectors among LEDs or in wearable VOC gas sensors.

MG53-IRS-1 (Mitsugumin 53-Insulin Receptor Substrate-1) Interaction Disruptor Sensitizes Insulin Signaling in Skeletal Muscle.

Mitsugumin 53 (MG53) is an E3 ligase that interacts with and ubiquitinates insulin receptor substrate-1 (IRS-1) in skeletal muscle; thus, an MG53-IRS-1 interaction disruptor (MID), which potentially sensitizes insulin signaling with an elevated level of IRS-1 in skeletal muscle, is an excellent candidate for treating insulin resistance. To screen for an MID, we developed a bimolecular luminescence complementation system using an N-terminal luciferase fragment fused with IRS-1 and a C-terminal luciferase fragment fused with an MG53 C14A mutant that binds to IRS-1 but does not have E3 ligase activity. An MID, which was discovered using the bimolecular luminescence complementation system, disrupted the molecular association of MG53 with IRS-1, thus abolishing MG53-mediated IRS-1 ubiquitination and degradation. Thus, the MID sensitized insulin signaling and increased insulin-elicited glucose uptake with an elevated level of IRS-1 in C2C12 myotubes. These data indicate that this MID holds promise as a drug candidate for treating insulin resistance.

Silencing of ST6Gal I enhances colorectal cancer metastasis by down-regulating KAI1 via exosome-mediated exportation and thereby rescues integrin signaling.

Aberrant sialylation has long been correlated with human cancer. Increased ST6 Gal I (ß-galactoside α 2, 6 sialyltransferase) and consequently higher levels of cell-surface α 2, 6 sialylation has been associated with human colorectal cancer (CRC) metastasis. We have extensive circumstantial data that sialylation is connected to cancer metastasis, but we do not understand in detail how sialylation can switch on/off multiple steps in cancer metastasis. To investigate the molecular mechanism underlying the ST6Gal I-mediated metastasis of CRC, we silenced the ST6Gal I gene in a metastatic SW620 CRC cell line (SW620-shST6Gal I) and examined the metastatic behavior of the cells. We found that various hallmarks of metastatic ability were considerably enhanced in ST6Gal 1-depleted SW620 clones, as assessed both in vitro and in vivo . In particular, the metastasis suppressor, KAI1, was down-regulated in ST6Gal I-deficient SW620 clones. This reflected the increased exosome-mediated exportation of KAI1, and was associated with a decrease in the KAI1-mediated inhibition of integrin. These findings indicate that gene silencing of ST6Gal I could enhance metastasis of CRC by down-regulating KAI1 activity and rescuing its negative effects on integrin signaling.

Aspirin Targets SIRT1 and AMPK to Induce Senescence of Colorectal Carcinoma Cells.

Cancer therapies attempt to destroy the entire tumor, but this tends to require toxic compounds and high doses of radiation. Recently, considerable attention has focused on therapy-induced senescence (TIS), which can be induced in cancer cells by low doses of therapeutic drugs or radiation and provides a barrier to tumor development. However, the molecular mechanisms governing TIS remain elusive. Special attention has been paid to the potential chemopreventive effect of aspirin against human colorectal cancer. In this study, we investigated the effects of aspirin on TIS of human colorectal carcinoma (CRC) cells and show that it occurs via sirtuin 1 (SIRT1) and AMP-activated protein kinase (AMPK), two key regulators of cellular metabolism. Aspirin increased the senescence of CRC cells, increased the protein levels of SIRT1, phospho-AMPK (T172), and phospho-acetyl CoA carboxylase (S79), and reduced the cellular level of ATP. Small-interfering RNA-mediated downregulation or pharmacological inhibition of SIRT1 or AMPK significantly attenuated the aspirin-induced cellular senescence in CRC cells. In contrast, treatment with a SIRT1 agonist or an AMP analog induced cellular senescence. Remarkably, SIRT1 knockdown abrogated the aspirin-induced activation of AMPK, and vice versa. During the progression of aspirin-induced cellular senescence in CRC cells, SIRT1 showed increased deacetylase activity at a relatively early time point but was characterized by decreased activity with increased cytoplasmic localization at a later time point. Collectively, these novel findings suggest that aspirin could provide anticancer effects by inducing senescence in human CRC cells through the reciprocal regulation of SIRT1-AMPK pathways.

Mitochondrial complex I deficiency enhances skeletal myogenesis but impairs insulin signaling through SIRT1 inactivation.

To address whether mitochondrial biogenesis is essential for skeletal myogenesis, C2C12 myogenesis was investigated after knockdown of NADH dehydrogenase (ubiquintone) flavoprotein 1 (NDUFV1), which is an oxidative phosphorylation complex I subunit that is the first subunit to accept electrons from NADH. The NDUFVI knockdown enhanced C2C12 myogenesis by decreasing the NAD(+)/NADH ratio and subsequently inactivating SIRT1 and SIRT1 activators (pyruvate, SRT1720, and resveratrol) abolished the NDUFV1 knockdown-induced myogenesis enhancement. However, the insulin-elicited activation of insulin receptor ß (IRß) and insulin receptor substrate-1 (IRS-1) was reduced with elevated levels of protein-tyrosine phosphatase 1B after NDUFV1 knockdown in C2C12 myotubes. The NDUFV1 knockdown-induced blockage of insulin signaling was released by protein-tyrosine phosphatase 1B knockdown in C2C12 myotubes, and we found that NDUFV1 or SIRT1 knockdown did not affect mitochondria biogenesis during C2C12 myogenesis. Based on these data, we can conclude that complex I dysfunction-induced SIRT1 inactivation leads to myogenesis enhancement but blocks insulin signaling without affecting mitochondria biogenesis.

Anterior open bite correction via molar intrusion: Diagnosis, advantages, and complications.

Anterior open bite can be effectively treated nonsurgically via molar intrusion. This technique, involving the intrusion of posterior teeth using temporary skeletal anchorage devices, prompts counterclockwise rotation of the mandible. This rotation not only corrects anterior open bite but also contributes to a decrease in anterior facial height, improvements in lip incompetency, and forward movement of the chin. For successful outcomes, temporary skeletal anchorage devices, installed on both the buccal and palatal sides, must deliver equivalent intrusion force to the maxillary teeth. Treatment planning should consider factors such as skeletal discrepancies, vertical excess, incisor exposure, and configuration of the occlusal plane. Clinicians are advised to closely monitor periodontal changes and consider overcorrection to ensure lasting stability and maintenance of incisal overlap post-treatment.

FRMD6 determines the cell fate towards senescence: involvement of the Hippo-YAP-CCN3 axis.

Cellular senescence, a hallmark of aging, is pathogenically linked to the development of aging-related diseases. This study demonstrates that FRMD6, an upstream component of the Hippo/YAP signaling cascade, is a key regulator of senescence. Proteomic analysis revealed that FRMD6 is upregulated in senescent IMR90 fibroblasts under various senescence-inducing conditions. Silencing FRMD6 mitigated the senescence of IMR90 cells, suggesting its requirement in senescence. Conversely, the overexpression of FRMD6 alone induced senescence in cells and in lung tissue, establishing a causal link. The elevated FRMD6 levels correlated well with increased levels of the inhibitory phosphorylated YAP/TAZ. We identified cellular communication network factor 3 (CCN3), a key component of the senescence-associated secretory phenotype regulated by YAP, whose administration attenuated FRMD6-induced senescence in a dose-dependent manner. Mechanistically, FRMD6 interacted with and activated MST kinase, which led to YAP/TAZ inactivation. The expression of FRMD6 was regulated by the p53 and SMAD transcription factors in senescent cells. Accordingly, the expression of FRMD6 was upregulated by TGF-ß treatment that activates those transcription factors. In TGF-ß-treated IMR90 cells, FRMD6 mainly segregated with p21, a senescence marker, but rarely segregated with α-SMA, a myofibroblast marker, which suggests that FRMD6 has a role in directing cells towards senescence. Similarly, in TGF-ß-enriched environments, such as fibroblastic foci (FF) from patients with idiopathic pulmonary fibrosis, FRMD6 co-localized with p16 in FF lining cells, while it was rarely detected in α-SMA-positive myofibroblasts that are abundant in FF. In sum, this study identifies FRMD6 as a novel regulator of senescence and elucidates the contribution of the FRMD6-Hippo/YAP-CCN3 axis to senescence.

Enhancement of Mechanical Properties of Multilayer Ceramic Capacitors through a BaTiO3/polydopamine Cover Layer.

To fabricate multilayer ceramic capacitors (MLCCs) that can withstand external impacts, technologies to achieve excellent adhesion and mechanical strength of the cover layer should be essentially developed. Low adhesion and strength of the cover layer can lead to delamination and cracks in the MLCC, respectively. In this study, we present a method for applying polydopamine (PDA), a mussel-inspired adhesive protein, for as robust cover layer on an MLCC. Barium titanate (BT) particles treated with PDA increase the dispersion stability of the BT/PDA slurry, preventing re-agglomeration of the particles and enhancing the adhesiveness and strength owing to the cohesive properties of PDA. Compared to the BT layer, the adhesion of the BT/PDA layer was significantly enhanced by 217%; consequently, the compression modulus of the BT/PDA cover layer increased by 29.4%. After firing, the N-doped graphitic PDA played an important role in producing an MLCC cover layer with increased hardness and toughness. Furthermore, the N-doped graphitic PDA with a hydrophobic surface forms tortuous moisture paths in the cover layer, preventing the degradation of insulation resistance of the MLCC.

Defining regorafenib as a senomorphic drug: therapeutic potential in the age-related lung disease emphysema.

Senescence, a hallmark of aging, is a factor in age-related diseases (ARDs). Therefore, targeting senescence is widely regarded as a practicable method for modulating the effects of aging and ARDs. Here, we report the identification of regorafenib, an inhibitor of multiple receptor tyrosine kinases, as a senescence-attenuating drug. We identified regorafenib by screening an FDA-approved drug library. Treatment with regorafenib at a sublethal dose resulted in effective attenuation of the phenotypes of ßPIX knockdown- and doxorubicin-induced senescence and replicative senescence in IMR-90 cells; cell cycle arrest, and increased SA-ß-Gal staining and senescence-associated secretory phenotypes, particularly increasing the secretion of interleukin 6 (IL-6) and IL-8. Consistent with this result, slower progression of ßPIX depletion-induced senescence was observed in the lungs of mice after treatment with regorafenib. Mechanistically, the results of proteomics analysis in diverse types of senescence indicated that growth differentiation factor 15 and plasminogen activator inhibitor-1 are shared targets of regorafenib. Analysis of arrays for phospho-receptors and kinases identified several receptor tyrosine kinases, including platelet-derived growth factor receptor α and discoidin domain receptor 2, as additional targets of regorafenib and revealed AKT/mTOR, ERK/RSK, and JAK/STAT3 signaling as the major effector pathways. Finally, treatment with regorafenib resulted in attenuation of senescence and amelioration of porcine pancreatic elastase-induced emphysema in mice. Based on these results, regorafenib can be defined as a novel senomorphic drug, suggesting its therapeutic potential in pulmonary emphysema.

Berberine inhibits human colon cancer cell migration via AMP-activated protein kinase-mediated downregulation of integrin ß1 signaling.

Colon cancer is associated with a poor prognosis, motivating strategies to prevent its development. An encouraging preventative strategy is the use of nutraceuticals; however, scientific verification of therapeutic functions and mechanisms of biological activity are necessary for the acceptance of dietary supplements in cancer treatment. Berberine is a benzylisoquinoline alkaloid extracted from many kinds of medicinal plants that has been extensively used as a Chinese traditional medicine. Recently, berberine has been reported to possess antitumoral activities. Among the various cellular targets of berberine is AMP-activated protein kinase (AMPK), which regulates tumor progression and metastasis. However, the specific role of berberine-induced AMPK activation and its effects on the metastatic potential of colon cancer remain largely unknown. The present study investigated berberine-induced activation of AMPK and its effects on colon cancer cell migration. Berberine decreased the migration of SW480 and HCT116 cells. We found that berberine activated AMPK in human colon cancer cell lines. Notably, berberine-induced activation of AMPK reduced the integrin ß1 protein levels and decreased the phosphorylation of integrin ß1 signaling targets. Knockdown of AMPKα1 subunits using small interfering RNA significantly attenuated berberine-induced downregulation of integrin ß1 and inhibition of tumor cell migration. Collectively, our results suggest that berberine-induced AMPK activation inhibits the metastatic potential of colon cancer cells by decreasing integrin ß1 protein levels and downstream signaling.

KAI1 suppresses HIF-1α and VEGF expression by blocking CDCP1-enhanced Src activation in prostate cancer.

BACKGROUND: KAI1 was initially identified as a metastasis-suppressor gene in prostate cancer. It is a member of the tetraspan transmembrane superfamily (TM4SF) of membrane glycoproteins. As part of a tetraspanin-enriched microdomain (TEM), KAI1 inhibits tumor metastasis by negative regulation of Src. However, the underlying regulatory mechanism has not yet been fully elucidated. CUB-domain-containing protein 1 (CDCP1), which was previously known as tetraspanin-interacting protein in TEM, promoted metastasis via enhancement of Src activity. To better understand how KAI1 is involved in the negative regulation of Src, we here examined the function of KAI1 in CDCP1-mediated Src kinase activation and the consequences of this process, focusing on HIF-1 α and VEGF expression. METHODS: We used the human prostate cancer cell line PC3 which was devoid of KAI1 expression. Vector-transfected cells (PC3-GFP clone #8) and KAI1-expressing PC3 clones (PC3-KAI1 clone #5 and #6) were picked after stable transfection with KAI1 cDNA and selection in 800 µg/ml G418. Protein levels were assessed by immunoblotting and VEGF reporter gene activity was measured by assaying luciferase activitiy. We followed tumor growth in vivo and immunohistochemistry was performed for detection of HIF-1, CDCP1, and VHL protein level. RESULTS: We demonstrated that Hypoxia-inducible factor 1α (HIF-1α) and VEGF expression were significantly inhibited by restoration of KAI1 in PC3 cells. In response to KAI1 expression, CDCP1-enhanced Src activation was down-regulated and the level of von Hippel-Lindau (VHL) protein was significantly increased. In an in vivo xenograft model, KAI1 inhibited the expression of CDCP1 and HIF-1α. CONCLUSIONS: These novel observations may indicate that KAI1 exerts profound metastasis-suppressor activity in the tumor malignancy process via inhibition of CDCP1-mediated Src activation, followed by VHL-induced HIF-1α degradation and, ultimately, decreased VEGF expression.

pSlugS158 immunohistochemistry is a novel promising mitotic marker for FFPE samples: a pilot study.

Slug is a transcription factor belonging to the slug/snail superfamily. The protein is involved in embryonic development and epithelial-mesenchymal transition of tumors. Slug is also under temporal regulation during cell cycle. Here, we examined relationship between pSlugS158 (site-specific phosphorylation) and the cell cycle, and checked whether its phosphorylation level reflects mitotic activity in tissue specimens. Cell cycle analysis was performed after cell synchronization. To evaluate pSlugS158 identifying mitotic figures, we performed immunohistochemistry (IHC) for pSlugS158 in various formalin-fixed paraffin-embedded tissues; in addition, mitotic counts were compared with those in sections stained with hematoxylin and eosin (HE) and IHC for PHH3, a mitotic marker. We found that the level of pSlugS158 protein increased specifically at M phase and decreased at the G1/S phases in vitro. In almost all tested tissues, nuclear stain of pSlugS158 was identified in the cell with mitotic figures. There was no significant difference in mitotic counts between HE- and pSlugS158-stained sections. In conclusion, pSlugS158 may be a novel and practical immunohistochemical marker for detecting mitotic figures in human tissues.

p21-activated kinase 4 controls the aggregation of α-synuclein by reducing the monomeric and aggregated forms of α-synuclein: involvement of the E3 ubiquitin ligase NEDD4-1.

Aggregation of misfolded alpha-synuclein (α-synuclein) is a central player in the pathogenesis of neurodegenerative diseases. Therefore, the regulatory mechanism underlying α-synuclein aggregation has been intensively studied in Parkinson's disease (PD) but remains poorly understood. Here, we report p21-activated kinase 4 (PAK4) as a key regulator of α-synuclein aggregation. Immunohistochemical analysis of human PD brain tissues revealed an inverse correlation between PAK4 activity and α-synuclein aggregation. To investigate their causal relationship, we performed loss-of-function and gain-of-function studies using conditional PAK4 depletion in nigral dopaminergic neurons and the introduction of lentivirus expressing a constitutively active form of PAK4 (caPAK4; PAK4S445N/S474E), respectively. For therapeutic relevance in the latter setup, we injected lentivirus into the striatum following the development of motor impairment and analyzed the effects 6 weeks later. In the loss-of-function study, Cre-driven PAK4 depletion in dopaminergic neurons enhanced α-synuclein aggregation, intracytoplasmic Lewy body-like inclusions and Lewy-like neurites, and reduced dopamine levels in PAK4DAT-CreER mice compared to controls. Conversely, caPAK4 reduced α-synuclein aggregation, as assessed by a marked decrease in both proteinase K-resistant and Triton X100-insoluble forms of α-synuclein in the AAV-α-synuclein-induced PD model. Mechanistically, PAK4 specifically interacted with the NEDD4-1 E3 ligase, whose pharmacological inhibition and knockdown suppressed the PAK4-mediated downregulation of α-synuclein. Collectively, these results provide new insights into the pathogenesis of PD and suggest PAK4-based gene therapy as a potential disease-modifying therapy in PD.

Characterization of non-equilibrium nanoparticle adsorption on a model biological substrate.

The kinetics of nanoparticle (NP) adsorption on a model biological interface (collagen) is measured in microfluidic channels using surface plasmon resonance (SPR) imaging over a range of CdSe/ZnS quantum dot concentrations to investigate the underlying binding process. Spherical CdSe/ZnS core-shell NP, derivatized with 3-mercaptopropionic acid (3-MPA), were considered to be model NPs because of their widespread use in biological applications and their relatively monodisperse size. The kinetic adsorption data suggests that the binding between the NP and the collagen substrate is irreversible at room temperature (pH approximately 7.4), and this type of adsorption process was further characterized in the context of a surface absorption model. Specifically, diffusion-limited adsorption was found to predominate the adsorption process at lower concentrations (<0.4 micromol/L), and NP adsorption was reaction-limited at higher concentration (>0.4 micromol/L). A limited pH study of our system indicates that NPs desorb from collagen under acidic conditions (pH 5.5); no significant desorption was observed under neutral and basic pH conditions. These observations are consistent with electrostatic interactions being the dominant force governing NP desorption from collagen substrates. Our present methodology for characterizing the seemingly irreversible NP adsorption complements our earlier study where NP adsorption onto weakly adsorbing surfaces (self-assembled monolayers) was characterized by Langmuir NP adsorption measurements.

Development of glucose sensor using two-photon adsorbed photopolymerization.

A novel glucose sensor was constructed, and its analytical potential examined. A chip-type three-electrode system for use in a flow-type electrochemical glucose sensor was fabricated using a UV lithography technique on a glass slide. An Ag/AgCl reference electrode was made by electroplating silver onto a Pt electrode and dipping in a saturated KCl solution for 30 min. In addition, a glucose-sensing electrode was fabricated using a two-photon adsorbed photopolymerization technique with a photo-reactive resin containing a glucose oxidase enzyme, ferrocene mediator, non-ionic surfactant, and carbon nanotubes. The cyclic voltammetry of the potassium ferrocyanide in the Pt sensor system showed a stable electrode condition. The response of the modified Pt sensor confirms the feasibility of using a two-photon adsorbed photopolymerization technique for the easy fabrication of functional biosensors.

Integrin-mediated adhesions in regulation of cellular senescence.

Bioinformatic and functional data link integrin-mediated cell adhesion to cellular senescence; however, the significance of and molecular mechanisms behind these connections are unknown. We now report that the focal adhesion-localized ßPAK-interacting exchange factor (ßPIX)-G protein-coupled receptor kinase interacting protein (GIT) complex controls cellular senescence in vitro and in vivo. ßPIX and GIT levels decline with age. ßPIX knockdown induces cellular senescence, which was prevented by reexpression. Loss of ßPIX induced calpain cleavage of the endocytic adapter amphiphysin 1 to suppress clathrin-mediated endocytosis (CME); direct competition of GIT1/2 for the calpain-binding site on paxillin mediates this effect. Decreased CME and thus integrin endocytosis induced abnormal integrin signaling, with elevated reactive oxygen species production. Blocking integrin signaling inhibited senescence in human fibroblasts and mouse lungs in vivo. These results reveal a central role for integrin signaling in cellular senescence, potentially identifying a new therapeutic direction.

Binding STAT2 by the acidic domain of human cytomegalovirus IE1 promotes viral growth and is negatively regulated by SUMO.

The human cytomegalovirus (HCMV) 72-kDa immediate-early 1 (IE1) protein is thought to modulate cellular antiviral functions impacting on promyelocytic leukemia (PML) nuclear bodies and signal transducer and activator of transcription (STAT) signaling. IE1 consists of four distinct regions: an amino-terminal region required for nuclear localization, a large central hydrophobic region responsible for PML targeting and transactivation activity, an acidic domain, and a carboxyl-terminal chromatin tethering domain. We found that the acidic domain of IE1 is required for binding to STAT2. A mutant HCMV encoding IE1(Delta421-475) with the acidic domain deleted was generated. In mutant virus-infected cells, IE1(Delta421-475) failed to bind to STAT2. The growth of mutant virus was only slightly delayed at a high multiplicity of infection (MOI) but was severely impaired at a low MOI with low-level accumulation of viral proteins. When cells were pretreated with beta interferon, the mutant virus showed an additional 1,000-fold reduction in viral growth, even at a high MOI, compared to the wild type. The inhibition of STAT2 loading on the target promoter upon infection was markedly reduced with mutant virus. Furthermore, sumoylation of IE1 at this acidic domain was found to abolish the activity of IE1 to bind to STAT2 and repress the interferon-stimulated genes. Our results provide genetic evidence that IE1 binding to STAT2 requires the 55-amino-acid acidic domain and promotes viral growth by interfering with interferon signaling and demonstrate that this viral activity is negatively regulated by a cellular sumoylation pathway.