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This correction notice is for an article titled "Identification and characterization of a set of conserved and new regulators of cytoskeletal organization, cell morphology and migration." The authors of the article discovered an error in Figure 6, where the images for siARC were incorrect and the same as the siZRANB images. The correct siARC images have now been included in the figure. The conclusions of the paper remain unaffected. The article provides a graph showing the effects of PMM depletion on cytoskeletal organization in HeLa cells. [Extracted from the article]

Small-molecule inhibitors of the CDK4/6 cell-cycle kinases have shown clinical efficacy in estrogen receptor (ER)-positive metastatic breast cancer, although their cytostatic effects are limited by primary and acquired resistance. Here we report that ER-positive breast cancer cells can adapt quickly to CDK4/6 inhibition and evade cytostasis, in part, via noncanonical cyclin D1-CDK2-mediated S-phase entry. This adaptation was prevented by cotreatment with hormone therapies or PI3K inhibitors, which reduced the levels of cyclin D1 (CCND1) and other G1-S cyclins, abolished pRb phosphorylation, and inhibited activation of S-phase transcriptional programs. Combined targeting of both CDK4/6 and PI3K triggered cancer cell apoptosis in vitro and in patient-derived tumor xenograft (PDX) models, resulting in tumor regression and improved disease control. Furthermore, a triple combination of endocrine therapy, CDK4/6, and PI3K inhibition was more effective than paired combinations, provoking rapid tumor regressions in a PDX model. Mechanistic investigations showed that acquired resistance to CDK4/6 inhibition resulted from bypass of cyclin D1-CDK4/6 dependency through selection of CCNE1 amplification or RB1 loss. Notably, although PI3K inhibitors could prevent resistance to CDK4/6 inhibitors, they failed to resensitize cells once resistance had been acquired. However, we found that cells acquiring resistance to CDK4/6 inhibitors due to CCNE1 amplification could be resensitized by targeting CDK2. Overall, our results illustrate convergent mechanisms of early adaptation and acquired resistance to CDK4/6 inhibitors that enable alternate means of S-phase entry, highlighting strategies to prevent the acquisition of therapeutic resistance to these agents. [ABSTRACT FROM AUTHOR]

The article presents research on the effects of positive end-expiratory pressure (PEEP) on ventilator-induced lung injury. It was previously theorized that increasing peak airway pressure during PEEP applications in healthy rats does not worsen ventilator-induced lung injury. In the research, sixty male rats, which were anesthetized and ventilated with varying PEEP, were used to prove the hypothesis. In conclusion, it was found that lung damages were worsened by PEEP and even contributing to fatality of previously health rats.

We characterized the role of protein tyrosine phosphatase (PTP)-a in focal adhesion (FA) formation and remodeling using wild-type and PTPa- deficient (PTP) cells. Compared with wild-type cells, spreading PTPo~ fibroblasts displayed fewer leading edges and formed elongated c~-actinin-enriched FA at the cell periphery. These fea- tures suggest the presence of slowly remodeling cell adhesions and were phenocopied in human fibroblasts in which PTPa was knocked down using short interfering RNA (siRNA) or in NIH- 3T3 fibroblasts expressing catalytically inactive (C433S/C723S) PTPr. Fluorescence recovery after photobleaching showed slower green fluorescence protein-a-actinin recovery in the FA of PTPo(~~ than wild-type cells. These alterations correlated with reduced cell spreading, adhesion, and polarization and retarded contraction of extracellular matrices in PTPc~~ fibroblasts. Ac- tivation of Racl and its recruitment to FA during spreading were diminished in cells expressing C433S/C723S PTP~z. Racl~ cells also displayed abnormally elongated and peripherally distributed FA that failed to remodel. Conversely, expression of constitutively active RacI restored normal FA remodeling in PTP' cells. We conclude that PTPa is required for remodeling of FA during cell spreading via a pathway involving RacI. [ABSTRACT FROM AUTHOR]

Interleukin-1 (IL-1)-induced Ca2+ signaling in fibroblasts is constrained by focal adhesions. This process involves the protein-tyrosine phosphatase SHP-2, which is critical for IL-1-induced phosphorylation of phospholipase Cγl, thereby enhancing IL-1-induced Ca2 release and ERK activation. Currently, the mechanisms by which SHP-2 modulates Ca2 release from the endoplasmic reticulum are not defined. We used immunoprecipitation and fluorescence protein-tagged SHP-2 or endoplasmic reticulum (ER)-protein expression vectors, and an ER-specific calcium indicator, to examine the functional relationships between SHP-2, focal adhesions, and IL-1-induced Ca2+ release from the ER. By total internal reflection fluorescence microscopy to image sub-plasma membrane compartments, SHP-2 co-localized with the ER-associated proteins calnexin and calreticulin at sites of focal adhesion formation in fibroblasts. IL-1β promoted time-dependent recruitment of SHP-2 and ER proteins to focal adhesions; this process was blocked in cells treated with small interfering RNA for SHP-2 and in cells expressing a Y542F SHP-2 mutant. IL-1 stimulated inositol 1,4,5-trisphosphate receptor-mediated Ca2+ release from the ER subjacent to the plasma membrane that was tightly localized around fibronectin-coated beads and was reduced 4-fold in cells expressing Tyr-542 SHP-2 mutant. In subcellular fractions enriched for ER proteins, immunoprecipitation demonstrated that IL-1-enhanced association of SHP-2 with the type 1 inositol 1,4,5- trisphosphate receptor was dependent on Tyr-542 of SHP-2. We conclude that Tyr-542 of SHP-2 modulates IL-1-induced Ca2+ signals and association of the ER with focal adhesions, [ABSTRACT FROM AUTHOR]

Interleukin-1β (IL-1β) mediates destruction of matrix collagens in diverse inflammatory diseases including arthritis, periodontitis, and pulmonary fibrosis by activating fibroblasts, cells that interact with matrix proteins through integrin-based adhesions. In vitro, IL-1β signaling is modulated by focal adhesions, supramolecular protein complexes that are enriched with tyrosine kinases and phosphatases. We assessed the importance of tyrosine phosphatases in regulating cell–matrix interactions and IL-1β signaling. In human gingival fibroblasts plated on fibronectin, IL-1β enhanced the maturation of focal adhesions as defined by morphology and enrichment with paxillin and α-actinin. IL-1β also induced activation of ERK and recruitment of phospho-ERK to focal complexes/adhesions. Treatment with the potent tyrosine phosphatase inhibitor pervanadate, in the absence of IL-1β, recapitulated many of these responses indicating the importance of tyrosine phosphatases. Immunoblotting of collagen bead-associated complexes revealed that the tyrosine phosphatase, SHP-2, was also enriched in focal complexes/adhesions. Depletion of SHP-2 by siRNA or by homologous recombination markedly altered IL-1β-induced ERK activation and maturation of focal adhesions. IL-1β-induced tyrosine phosphorylation of SHP-2 on residue Y542 promoted focal adhesion maturation. Association of Gab1 with SHP-2 in focal adhesions correlated temporally with activation of ERK and was abrogated in cells expressing mutant (Y542F) SHP-2. We conclude that IL-1β mediated maturation of focal adhesions is dependent on tyrosine phosphorylation of SHP-2 at Y542, leading to recruitment of Gab1, a process that may influence the downstream activation of ERK. J. Cell. Physiol. 207: 132–143, 2006. © 2005 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Focal adhesion complexes are actin-rich, cytoskeletal structures that mediate cell adhesion to the substratum and also selectively regulate signal transduction pathways required for interleukin (IL)-1β signaling to the MAP kinase, ERK. IL-1-induced ERK activation is markedly diminished in fibroblasts deprived of focal adhesions whereas activation of p38 and JNK is unaffected. While IL-1 signaling is known to involve the activity of protein and lipid kinases including MAP kinases, FAK, and PI3K, little is known about the role of phosphatases in the regulation of IL-1 signal generation and attenuation. Here we demonstrate that SHP-2, a protein tyrosine phosphatase present in focal adhesions, modulates IL-1-induced ERK activation and the transient actin stress fiber disorganization that occurs following IL-1 treatment in human gingival fibroblasts. Using a combination of immunoblotting, immunoprecipitation, and immunostaining we show that SHP-2 is present in nascent focal adhesions and undergoes phosphorylation on tyrosine 542 in response to IL-1 stimulation. Blocking anti-SHP-2 antibodies, electoporated into the cytosol of fibroblasts, inhibited IL-1-induced ERK activation, actin filament assembly, and cell contraction, indicating a role for SHP-2 in these processes. In summary, our data indicate that SHP-2, a focal adhesion-associated protein, participates in IL-1-induced ERK activation likely via an adaptor function. [ABSTRACT FROM AUTHOR]

Recent evidence indicates that the gut microbiota (GM) has a significant impact on the inflammatory bowel disease (IBD) progression. Our aim was to investigate the GM profiles, the Microbial Dysbiosis Index (MDI) and the intestinal microbiota-associated markers in relation to IBD clinical characteristics and disease state. We performed 16S rRNA metataxonomy on both stools and ileal biopsies, metabolic dysbiosis tests on urine and intestinal permeability and mucosal immunity activation tests on the stools of 35 IBD paediatric patients. On the GM profile, we assigned the MDI to each patient. In the statistical analyses, the MDI was correlated with clinical parameters and intestinal microbial-associated markers. In IBD patients with high MDI, Gemellaceae and Enterobacteriaceae were increased in stools, and Fusobacterium, Haemophilus and Veillonella were increased in ileal biopsies. Ruminococcaceae and WAL_1855D were enriched in active disease condition; the last one was also positively correlated to MDI. Furthermore, the MDI results correlated with PUCAI and Matts scores in ulcerative colitis patients (UC). Finally, in our patients, we detected metabolic dysbiosis, intestinal permeability and mucosal immunity activation. In conclusion, the MDI showed a strong association with both severity and activity of IBD and a positive correlation with clinical scores, especially in UC. Thus, this evidence could be a useful tool for the diagnosis and prognosis of IBD. [ABSTRACT FROM AUTHOR]

Williams–Beuren syndrome (WBS) is a rare genetic neurodevelopmental disorder with multi-systemic manifestations. The evidence that most subjects with WBS face gastrointestinal (GI) comorbidities, have prompted us to carry out a metaproteomic investigation of their gut microbiota (GM) profile compared to age-matched healthy subjects (CTRLs). Metaproteomic analysis was carried out on fecal samples collected from 41 individuals with WBS, and compared with samples from 45 CTRLs. Stool were extracted for high yield in bacterial protein group (PG) content, trypsin-digested and analysed by nanoLiquid Chromatography-Mass Spectrometry. Label free quantification, taxonomic assignment by the lowest common ancestor (LCA) algorithm and functional annotations by COG and KEGG databases were performed. Data were statistically interpreted by multivariate and univariate analyses. A WBS GM functional dissimilarity respect to CTRLs, regardless age distribution, was reported. The alterations in function of WBSs GM was primarily based on bacterial pathways linked to carbohydrate transport and metabolism and energy production. Influence of diet, obesity, and GI symptoms was assessed, highlighting changes in GM biochemical patterns, according to WBS subsets' stratification. The LCA-derived ecology unveiled WBS-related functionally active bacterial signatures: Bacteroidetes related to over-expressed PGs, and Firmicutes, specifically the specie Faecalibacterium prausnitzii, linked to under-expressed PGs, suggesting a depletion of beneficial bacteria. These new evidences on WBS gut dysbiosis may offer novel targets for tailored interventions. [ABSTRACT FROM AUTHOR]

Williams–Beuren syndrome (WBS) is a multisystem genetic disease caused by the deletion of a region of 1.5–1.8 Mb on chromosome 7q11.23. The elastin gene seems to account for several comorbidities and distinct clinical features such including cardiovascular disease, connective tissue abnormalities, growth retardation, and gastrointestinal (GI) symptoms. Increasing evidence points to alterations in gut microbiota composition as a primary or secondary cause of some GI or extra-intestinal characteristics. In this study, we performed the first exploratory analysis of gut microbiota in WBS patients compared to healthy subjects (CTRLs) using 16S rRNA amplicon sequencing, by investigating the gut dysbiosis in relation to diseases and comorbidities. We found that patients with WBS have significant dysbiosis compared to age-matched CTRLs, characterized by an increase in proinflammatory bacteria such as Pseudomonas, Gluconacetobacter and Eggerthella, and a reduction of anti-inflammatory bacteria including Akkermansia and Bifidobacterium. Microbial biomarkers associated with weight gain, GI symptoms and hypertension were identified. Gut microbiota profiling could represent a new tool that characterise intestinal dysbiosis to complement the clinical management of these patients. In particular, the administration of microbial-based treatments, alongside traditional therapies, could help in reducing or preventing the burden of these symptoms and improve the quality of life of these patients. [ABSTRACT FROM AUTHOR]

Grb2-associated binder (Gab)2 functions downstream of a variety of receptor and cytoplasmic tyrosine kinases as a docking platform for specific signal transducers and performs important functions in both normal physiology and oncogenesis. Gab2 signalling is promoted by its association with specific receptors through the adaptor Grb2. However, the molecular mechanisms that attenuate Gab2 signals have remained unclear. We now demonstrate that growth factor-induced phosphorylation of Gab2 on two residues, S210 and T391, leads to recruitment of 14-3-3 proteins. Together, these events mediate negative-feedback regulation, as Gab2S210A/T391A exhibits sustained receptor association and signalling and promotes cell proliferation and transformation. Importantly, introduction of constitutive 14-3-3-binding sites into Gab2 renders it refractory to receptor activation, demonstrating that site-selective binding of 14-3-3 proteins is sufficient to terminate Gab2 signalling. Furthermore, this is associated with reduced binding of Grb2. This leads to a model where signal attenuation occurs because 14-3-3 promotes dissociation of Gab2 from Grb2, and thereby uncouples Gab2 from the receptor complex. This represents a novel regulatory mechanism with implications for diverse tyrosine kinase signalling systems. [ABSTRACT FROM AUTHOR]

Interleukin-1 (IL-1) signaling is dependent on focal adhesions, structures that are enriched with tyrosine kinases and phosphatases. Because the non-receptor tyrosine phosphatase Src homology 2 domain-containing protein tyrosine phosphatase-2 (SHP-2) is enriched in focal adhesions and IL-l-induced ERK activation requires increased Ca2+, we determined whether SHP-2 modulates IL-l-induced Ca2+ signaling. In SHP-2-deficient fibroblasts, IL-l-induced Ca2+ signaling and ERK activation were markedly diminished compared with cells expressing SHP-2. IL-l-induced Ca2+ release from the endoplasmic reticulum occurred in the vicinity of focal adhesions and was strongly inhibited by the blockage of phospholipase C (PLC) catalytic activity. Immunoprecipitation and immunostaining showed that SHP-2, the endoplasmic reticulum-specific protein calnexin, and PLCγl were associated with focal adhesions; however, these associations and IL-l-induced ERK activation dissipated after cells were plated on non-integrin substrates. IL-1 promoted phosphorylation of SHP-2 and PLCγ1. IL-l-induced phosphorylation of PLCγ1 was diminished in SHP-2-deficient cells but was restored by stable transfection with SHP-2. BAPTA/AM (1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-acetic acid tetrakis(acetoxymethyl ester)) blocked IL-l-induced phosphorylation of SHP-2 and PLCγ1, indicating mutually dependent interactive roles for Ca2+, SHP-2, and PLCγ1 in IL-1 signaling. We conclude that SHP-2 is critical for IL-l-induced phosphorylation of PLCγ1 and thereby enhances IL-l-induced Ca2+ release and ERK activation. Focal adhesions co-localizing with the endoplasmic reticulum may provide molecular staging sites required for ERK activation. [ABSTRACT FROM AUTHOR]

Calcium (Ca2+) signaling by the pro-inflammatory cytokine interleukin-1 (IL-1) is dependent on focal adhesions, which contain diverse structural and signaling proteins including protein phosphatases. We examined here the role of protein-tyrosine phosphatase (PTP) α in regulating IL-1-induced Ca2+ signaling in fibroblasts. IL-1 promoted recruitment of PTPα to focal adhesions and endoplasmic reticulum (ER) fractions, as well as tyrosine phosphorylation of the ER Ca2+ release channel IP3R. In response to IL-1, catalytically active PTPa was required for Ca2+ release from the ER, Src-dependent phosphorylation of IP3R1 and accumulation of IP3R1 in focal adhesions. In pulldown assays and immunoprecipitations PTPα was required for the association of PTPa with IP3R1 and c-Src, and this association was increased by IL-1. Collectively, these data indicate that PTPa acts as an adaptor to mediate functional links between focal adhesions and the ER that enable IL-1 induced Ca2+ signaling. [ABSTRACT FROM AUTHOR]

During acute inflammation, neutrophil-mediated injury to epithelium may lead to disruption of epithelial function, including the induction of epithelial apoptosis. Herein, we report the effects of neutrophil transmigration and of purified leukocyte elastase on epithelial cell survival. Neutrophil transmigration induced apoptosis of epithelial cells [control monolayers: 5 ± 1 cells/25 high-power fields (HPF) vs. neutrophil-treated monolayers: 29 ± 10 cells/HPF, P < 0.05, n = 3 as determined by terminal deoxynucleotidyl transferase dUTP nick-end labeling assay] as did low concentrations (0.1 U/ml) of purified leukocyte elastase (control monolayers: 6.4 ± 2.5% apoptotic vs. elastase: 26.2 ± 2.9% apoptotic, P < 0.05, as determined by cytokeratin 18 cleavage). Treatment with elastase resulted in decreased mitochondrial membrane potential, release of cytochrome c to the cytosol, and cleavage of caspases-9 and -3 as determined by Western blot analysis, implicating altered mitochondrial membrane permeability as a primary mechanism for elastase-induced apoptosis. Additionally, incubation of epithelial cells with leukocyte elastase resulted in an early increase followed by a decrease in the phosphorylation of epithelial Akt, a serine/threonine kinase important in cell survival. Inhibition of epithelial Akt before elastase treatment potentiated epithelial cell apoptosis, suggesting that the initial activation of Akt represents a protective response by the epithelial cells to the proapoptotic effects of leukocyte elastase. Taken together, these observations suggest that epithelial cells exhibit a dual response to cellular stress imposed by leukocyte elastase with a proapoptotic response mediated via early alterations in mitochondrial membrane permeability countered by activation of the survival pathway involving Akt. [ABSTRACT FROM AUTHOR]