Cell Adhesion Function Research Articles

The structural basis of β2 integrin intra-cellular multi-protein complexes.

In multicellular organisms, cell adhesion is a pivotal physiological process which is essential for cell-cell communications, cell migration, and interactions with extracellular matrix. Integrins, a family of large hetero-dimeric type I membrane proteins, are known for driving cell adhesion functions. Among 24 different integrins, four β2 integrins, αL β2, αM β2, αX β2 and αD β2, are specific for cell adhesion and migration of leukocytes. Many cytosolic proteins interact with short cytosolic tails (CTs) of β2 and other integrins which are essential in bi-directional signaling processes. Further, phosphorylation of CTs of integrins regulates binding of intra-cellular proteins and signaling systems. In this review, recent advances in structures and interactions of multi-protein complexes of integrin tails, with a focus on β2 integrin, and cytosolic proteins are discussed along with a proposed future direction.

Single-Cell Profiling of the Immune Atlas of Tumor-Infiltrating Lymphocytes in Endometrial Carcinoma.

Simple SummaryImmunotherapy has a unique potential for improving various types of cancer treatment. However, related studies in endometrial carcinoma are lacking. Further studies on the tumor-infiltrating lymphocyte populations are vital. We firstly mapped the immune atlas of lymphocytes in type I endometrial carcinoma via single-cell RNA sequencing, mass cytometry and flow cytometry analysis. Three transcriptionally distinct NK cell subsets with different antitumor functions were identified. Some CD103+ CD8+ T cells were also defined as tissue-resident memory T cells in endometrial carcinoma. Both our retrospective study and analysis of a public repository suggest the correlation between antitumor function of CD103+ CD8+ T cells and EC prognosis. Certain key molecular mechanisms potentially determining the phenotypes of NK cells and CD103+ CD8+ T cells were highlighted and might serve as novel therapeutic targets.Endometrial carcinoma (EC) is a gynecological malignancy with a high incidence; however, thorough studies on tumor-infiltrating lymphocyte (TIL) populations in EC are lacking. We aimed to map the immune atlas of TILs in type I EC via single-cell RNA sequencing (scRNA-seq), mass cytometry and flow cytometry analysis. We found that natural killer (NK) cells and CD8+ T lymphocytes were the major components of TILs in EC patients. We first identified three transcriptionally distinct NK cell subsets, which are likely to possess diverse anti-tumor functions. Additionally, CD103+ cells substantially contributed to the CD8+ T cell population. The signature gene expression of CD103+ CD8+ T cells indicated the tissue residency, immunological memory, and exhaustion properties of this cell subset, which were defined as tissue-resident memory T cells (TRM cells). Moreover, based on scRNA-seq and mass cytometry analysis, we first identified the intrinsic heterogeneity of CD103+ CD8+ T cells that were thought to have a distinct cytotoxicity, cell adhesion and exhaustion status functions. Collectively, distinct subsets of NK cells were found and might shed light on future investigations. CD103+ CD8+ T cell population may be an important immunotherapeutic target in EC and targeting this cell population with combined immunosuppressive therapy might improve the efficacy of immunotherapy for EC.

Revealing the impacts on shaping scutate scales in goose skin

Feather follicles and scales are two types of skin appendages distributed on different parts of avian skin. The morphogenesis and development of scales in waterfowl remain largely unknown. Here, we used H&E staining, ISH and RNA sequencing to reveal the morphological and molecular variations at the early development of scutate scales in goose shank skin. Transcriptome analysis produced 1824 differentially expressed genes (DEGs) regulating the induction of scales and further enriched gene function in cell adhesion and Wnt signaling pathway, etc. A total of 8 candidate genes (ALDOC, CSRP2, KRT15, KRT75, LGALS1, S100A6, OGN and SFRP2) were further detected by RT-qPCR to show upregulated (6 genes) and downregulated (2 genes) from pre-placodal to placode stage during the induction of goose scales. The localization of 7 candidate genes (ALDOC, CSRP2, CD109, KRT15, KRT75, S100A6, and OGN) by ISH suggests the potential roles for dermal and epidermal development during the induction of scutate scales. The dynamic molecular changes and specific gene expression patterns revealed in this report provide general knowledge of scale development in waterfowl as well as skin appendage diversity.

DNA methylation changes in response to neoadjuvant chemotherapy are associated with breast cancer survival

BackgroundLocally advanced breast cancer is a heterogeneous disease with respect to response to neoadjuvant chemotherapy (NACT) and survival. It is currently not possible to accurately predict who will benefit from the specific types of NACT. DNA methylation is an epigenetic mechanism known to play an important role in regulating gene expression and may serve as a biomarker for treatment response and survival. We investigated the potential role of DNA methylation as a prognostic marker for long-term survival (> 5 years) after NACT in breast cancer.MethodsDNA methylation profiles of pre-treatment (n = 55) and post-treatment (n = 75) biopsies from 83 women with locally advanced breast cancer were investigated using the Illumina HumanMethylation450 BeadChip. The patients received neoadjuvant treatment with epirubicin and/or paclitaxel. Linear mixed models were used to associate DNA methylation to treatment response and survival based on clinical response to NACT (partial response or stable disease) and 5-year survival, respectively. LASSO regression was performed to identify a risk score based on the statistically significant methylation sites and Kaplan–Meier curve analysis was used to estimate survival probabilities using ten years of survival follow-up data. The risk score developed in our discovery cohort was validated in an independent validation cohort consisting of paired pre-treatment and post-treatment biopsies from 85 women with locally advanced breast cancer. Patients included in the validation cohort were treated with either doxorubicin or 5-FU and mitomycin NACT.ResultsDNA methylation patterns changed from before to after NACT in 5-year survivors, while no significant changes were observed in non-survivors or related to treatment response. DNA methylation changes included an overall loss of methylation at CpG islands and gain of methylation in non-CpG islands, and these changes affected genes linked to transcription factor activity, cell adhesion and immune functions. A risk score was developed based on four methylation sites which successfully predicted long-term survival in our cohort (p = 0.0034) and in an independent validation cohort (p = 0.049).ConclusionOur results demonstrate that DNA methylation patterns in breast tumors change in response to NACT. These changes in DNA methylation show potential as prognostic biomarkers for breast cancer survival.

Nephrin expression in human epidermal keratinocytes and its implication in poor wound closure.

Nephrin is a type-1 transmembrane protein and a component of the slit diaphragm renal-filtration barrier. It has several functions in actin remodeling and cell-cell adhesion. Nephrin is principally located in the kidney glomerulus, but several studies have reported that nephrin is found in the pancreas, brain, and placenta. However, nephrin expression and its role in human skin have not yet been reported. First, using single-cell RNA sequencing, immunohistochemistry, and immuno-electron microscopy, nephrin expression was confirmed in human-skin epidermal keratinocytes. Nephrin expression colocalized with the expression of zonula occludens-1 in keratinocytes and was closely related to keratinocyte cell density, proliferation, and migration. High glucose treatment decreased nephrin expression and compromised keratinocyte cell migration without yes-associated protein nuclear entry. This reduced cell migration under high glucose conditions was improved in nephrin-overexpressing keratinocytes. Nephrin was highly expressed on the margins of re-epithelized epidermis based on in vivo mice and ex vivo human skin wound models. The results demonstrate that nephrin is expressed in human-skin keratinocytes and functions in cell adhesion, proliferation, and migration. In conclusion, this study suggests that nephrin may have a variety of physiological roles in human skin.

Detection of Epithelial-Mesenchymal Transition Markers in High Grade Bladder Cancer and Special Variants of Urothelial Carcinoma.

Transitional cell carcinoma is considered the most predominant type of bladder cancer. Bladder can cer can also be found as squamous cell carcinoma that accounts for 5% of the total bladder cancer due to its etiology. The biomarkers associated with grade, prognosis, and stage of the disease are not well proved and known however, many studies have pointed to the association between SNAL/SLUG and Twist2 to the overall survival in patients with bladder cancer. These biomarkers were found to have a crucial role in inhibiting cadherin mediators specifically E-cadherin which are found normally in high level to integrate cell adhesion and normal function of the bladder. This research aims to detect SNAL/SLUG and Twist2 biomarkers in specimens of patients with bladder cancer and to detect their impact on E-cadherin, a tumor suppressor mediator responsible for improving survival and prevent metastasis. Materials and Methods:Using 150 archival tissue blocks from human bladder cancer cases to detect expression of SNAIL/SLUG and Twist2 in relation to loss of E-cadherin by immunohistochemical method. Results:Our results have revealed that in squamous cell carcinoma 40 specimens showed marked Twist 2 expression, and 30 specimens showed marked snail/slug biomarkers expression while poorly differentiated cancer cases showed marked expression of Twist 2 in 60 specimens and marked expression of Snail/slug marked expression in 50 specimens. Both were associated with E-cadherin loss. Among the 100 specimens with transitional cell carcinoma, 70 specimens showed divergent differentiation with 7 subtypes each showed different medium to high expression of Snail/Slug and Twist 2 biomarkers with the loss of E-cadherin. E-cadherin was strongly associated with the inverse increase in SNAL/SLUG and Twist2 biomarkers in urothelial carcinoma. Conclusion:Detection of SNAIL/SLUG and Twist 2 biomarkers in urothelial cancer is an important predictor for the loss of E-cadherin, a cornerstone in urinary bladder cell adhesion and its loss in urothelial carcinoma may contribute to cancer invasion and poor prognosis.

Nicotine Affects Multiple Biological Processes in EpiDermTM Organotypic Tissues and Keratinocyte Monolayers

Dermal exposure to nicotine is common due to the widespread use of tobacco products. Here, we assessed the effects of nicotine at concentrations found in thirdhand smoke (THS) contaminated environments and electronic cigarette (EC) spills or leaks on a 3D human skin model (EpiDermTM) and on submerged keratinocyte cultures. Air liquid interface treatment of EpiDermTM with 10 or 400 μg/mL of nicotine for 24 h followed by proteomics analysis showed altered pathways related to inflammation, protein synthesis, cell–cell adhesion, apoptosis, and mitochondrial function. Submerged cultured keratinocytes were used to validate the proteomics data and further characterize the response of skin cells to nicotine. Mitochondrial phenotype changed from networked to punctate in keratinocytes treated with 10 or 400 μg/mL of nicotine for 48 h and 24 h, respectively. After 72 h, all concentrations of nicotine caused a significant decrease in the networked phenotype. In Western blots, keratinocytes exposed to 400 μg/mL of nicotine had a significant decrease in mitofusin 2, while mitofusin 1 decreased after 72 h. The shift from networked to punctate mitochondria correlated with a decrease in mitofusin 1/2, a protein needed to establish and maintain the networked phenotype. Mitochondrial changes were reversible after a 24 h recovery period. Peroxisomes exposed to 400 μg/mL of nicotine for 24 h became enlarged and were fewer in number. Nicotine concentrations in THS and EC spills altered the proteome profile in EpiDermTM and damaged organelles including mitochondria and peroxisomes, which are involved in ROS homeostasis. These changes may exacerbate skin infections, inhibit wound healing, and cause oxidative damage to cells in the skin.

Cell adhesion and immune response, two main functions altered in the transcriptome of seasonally regressed testes of two mammalian species.

In species with seasonal breeding, male specimens undergo substantial testicular regression during the nonbreeding period of the year. However, the molecular mechanisms that control this biological process are largely unknown. Here, we report a transcriptomic analysis on the Iberian mole, Talpa occidentalis, in which the desquamation of live, nonapoptotic germ cells is the major cellular event responsible for testis regression. By comparing testes at different reproductive states (active, regressing, and inactive), we demonstrate that the molecular pathways controlling the cell adhesion function in the seminiferous epithelium, such as the MAPK, ERK, and TGF-β signaling, are altered during the regression process. In addition, inactive testes display a global upregulation of genes associated with immune response, indicating a selective loss of the "immune privilege" that normally operates in sexually active testes. Interspecies comparative analyses using analogous data from the Mediterranean pine vole, a rodent species where testis regression is controlled by halting meiosis entry, revealed a common gene expression signature in the regressed testes of these two evolutionary distant species. Our study advances in the knowledge of the molecular mechanisms associated to gonadal seasonal breeding, highlighting the existence of a conserved transcriptional program of testis involution across mammalian clades.

Role of Teneurin C-Terminal Associated Peptides (TCAP) on Intercellular Adhesion and Communication.

The teneurin C-terminal associated peptides (TCAP) are encoded by the terminal exon of all metazoan teneurin genes. Evidence supports the liberation of a soluble TCAP peptide either by proteolytic cleavage from the mature transmembrane teneurin protein or by a separately transcribed mRNA. Synthetic versions of TCAP, based on its genomic structure, are efficacious at regulating intercellular communication by promoting neurite outgrowth and increasing dendritic spine density in vitro and in vivo in rodent models. This is achieved through cytoskeletal re-arrangement and metabolic upregulation. The putative receptors for TCAPs are the latrophilin (LPHN) family of adhesion G-protein coupled receptors, which facilitate TCAP’s actions through G-proteins associated with cAMP and calcium-regulating signalling pathways. The teneurin/TCAP and latrophilin genes are phylogenetically ancient, likely serving primitive functions in cell adhesion and energy regulation which have been since adapted for a more complex role in synaptogenesis in vertebrate nervous systems.

Beyond the Channels: Adhesion Functions of Aquaporin 0 and Connexin 50 in Lens Development.

Lens, an avascular tissue involved in light transmission, generates an internal microcirculatory system to promote ion and fluid circulation, thus providing nutrients to internal lens cells and excreting the waste. This unique system makes up for the lack of vasculature and distinctively maintains lens homeostasis and lens fiber cell survival through channels of connexins and other transporters. Aquaporins (AQP) and connexins (Cx) comprise the majority of channels in the lens microcirculation system and are, thus, essential for lens development and transparency. Mutations of AQPs and Cxs result in abnormal channel function and cataract formation. Interestingly, in the last decade or so, increasing evidence has emerged suggesting that in addition to their well-established channel functions, AQP0 and Cx50 play pivotal roles through channel-independent actions in lens development and transparency. Specifically, AQP0 and Cx50 have been shown to have a unique cell adhesion function that mediates lens development and transparency. Precise regulation of cell-matrix and cell-cell adhesion is necessary for cell migration, a critical process during lens development. This review will provide recent advances in basic research of cell adhesion mediated by AQP0 and Cx50.

Bi-layered carboxymethyl cellulose-collagen vitrigel dual-surface adhesion-prevention membrane

During wound regeneration, both cell adhesion and adhesion-inhibitory functions must be controlled in parallel. We developed a membrane with dual surfaces by merging the properties of carboxymethyl cellulose (CMC) and collagen using vitrification. A rigid membrane was formed by vitrification of a bi-layered CMC and collagen hydrogel without using cross-linking reagents, thus providing dual functions, strong cell adhesion-inhibition with the CMC layer, and cell adhesion with the collagen layer. We referred to this bi-layered CMC-collagen vitrigel membrane as “Bi-C-CVM” and optimized the process and materials. The introduction of the CMC layer conferred a “tough but stably wet” property to Bi-C-CVM. This enables Bi-C-CVM to cover wet tissue and make the membrane non-detachable while preventing tissue adhesion on the other side. The bi-layered vitrification procedure can expand the customizability of collagen vitrigel devices for wider medical applications.

Cdc42/Rac Interactive Binding Containing Effector Proteins in Unicellular Protozoans With Reference to Human Host: Locks of the Rho Signaling.

Small GTPases are the key to actin cytoskeleton signaling, which opens the lock of effector proteins to forward the signal downstream in several cellular pathways. Actin cytoskeleton assembly is associated with cell polarity, adhesion, movement and other functions in eukaryotic cells. Rho proteins, specifically Cdc42 and Rac, are the primary regulators of actin cytoskeleton dynamics in higher and lower eukaryotes. Effector proteins, present in an inactive state gets activated after binding to the GTP bound Cdc42/Rac to relay a signal downstream. Cdc42/Rac interactive binding (CRIB) motif is an essential conserved sequence found in effector proteins to interact with Cdc42 or Rac. A diverse range of Cdc42/Rac and their effector proteins have evolved from lower to higher eukaryotes. The present study has identified and further classified CRIB containing effector proteins in lower eukaryotes, focusing on parasitic protozoans causing neglected tropical diseases and taking human proteins as a reference point to the highest evolved organism in the evolutionary trait. Lower eukaryotes’ CRIB containing proteins fall into conventional effector molecules, PAKs (p21 activated kinase), Wiskoit-Aldrich Syndrome proteins family, and some have unique domain combinations unlike any known proteins. We also highlight the correlation between the effector protein isoforms and their selective specificity for Cdc42 or Rac proteins during evolution. Here, we report CRIB containing effector proteins; ten in Dictyostelium and Entamoeba, fourteen in Acanthamoeba, one in Trypanosoma and Giardia. CRIB containing effector proteins that have been studied so far in humans are potential candidates for drug targets in cancer, neurological disorders, and others. Conventional CRIB containing proteins from protozoan parasites remain largely elusive and our data provides their identification and classification for further in-depth functional validations. The tropical diseases caused by protozoan parasites lack combinatorial drug targets as effective paradigms. Targeting signaling mechanisms operative in these pathogens can provide greater molecules in combatting their infections.

Phosphoproteomic profiling of influenza virus entry reveals infection-triggered filopodia induction counteracted by dynamic cortactin phosphorylation.

Binding of influenza virus to its receptor triggers signaling cascades that reprogram the cell for infection. To elucidate global virus-induced changes to the cellular signaling landscape, we conducted a quantitative phosphoproteomic screen with human and avian influenza viruses. Proteins with functions in cell adhesion and cytoskeletal remodeling are overrepresented among the hits, and the majority of factors undergoing phosphorylation changes have a significant impact on infection efficiency. We show that influenza virus induces the formation of filopodia through Cdc42 signaling, which results in enhanced virus endocytosis. The host cell counteracts this mechanism with cortactin, a regulator of actin polymerization that becomes phosphorylated in response to virus binding and translocates to the cell cortex, where it limits filopodia formation and virus uptake. Overall, our study reveals the signaling cascades induced by influenza virus receptor engagement and uncovers virus-induced filopodia formation that is counteracted by the host cell.

Titanium dioxide nanoparticles perturb the blood-testis barrier via disruption of actin-based cell adhesive function.

As one of the most commonly used nanoparticles, titanium dioxide nanoparticles (TiO2-NPs) are widely used as coating reagents in cosmetics, medicine and other industries. The increasing risk of exposure to TiO2-NPs raises concerns about their safety. In this study, we investigated the mechanism by which TiO2-NPs cross the blood-testis barrier (BTB). TM-4 cells were selected as an in vitro Sertoli cell model of BTB. Cell viability, cell morphological changes, apoptosis, oxidative damage, and the expression levels of actin regulatory and tight junction (TJ) proteins were assessed in TM-4 cells treated with 3-nm and 24-nm TiO2-NPs. Cells treated with 3-nm TiO2-NPs exhibited increased cytotoxicity and decreased Annexin II expression, whereas cells treated with 24-nm TiO2-NPs exhibited increased Arp 3 and c-Src expression. Both TiO2-NPs induced significant oxidative stress, decreased the expression of TJ proteins (occludin, ZO-1 and claudin 5), damaged the TJ structure, and exhibited enlarged gaps between TM-4 cells. Our results indicated that both TiO2-NPs crossed the BTB by disrupting actin-based adhesive junctions of TM-4 cells; however, apoptosis was not observed. Our results provide new insights into how TiO2-NPs cross the BTB.

Integrative Studies of Human Cord Blood Derived Mononuclear Cells and Umbilical Cord Derived Mesenchyme Stem Cells in Ameliorating Bronchopulmonary Dysplasia.

Bronchopulmonary dysplasia (BPD) is a common pulmonary complication observed in preterm infants that is composed of multifactorial pathogenesis. Current strategies, albeit successful in moderately reducing morbidity and mortality of BPD, failed to draw overall satisfactory conclusion. Here, using a typical mouse model mimicking hallmarks of BPD, we revealed that both cord blood-derived mononuclear cells (CB-MNCs) and umbilical cord-derived mesenchymal stem cells (UC-MSCs) are efficient in alleviating BPD. Notably, infusion of CB-MNCs has more prominent effects in preventing alveolar simplification and pulmonary vessel loss, restoring pulmonary respiratory functions and balancing inflammatory responses. To further elucidate the underlying mechanisms within the divergent therapeutic effects of UC-MSC and CB-MNC, we systematically investigated the long noncoding RNA (lncRNA)–microRNA (miRNA)–messenger RNA (mRNA) and circular RNA (circRNA)–miRNA–mRNA networks by whole-transcriptome sequencing. Importantly, pathway analysis integrating Gene Ontology (GO)/Kyoto Encyclopedia of Genes and Genomes (KEGG)/gene set enrichment analysis (GSEA) method indicates that the competing endogenous RNA (ceRNA) network is mainly related to the regulation of GTPase activity (GO: 0043087), extracellular signal-regulated kinase 1 (ERK1) and ERK2 signal cascade (GO: 0070371), chromosome regulation (GO: 0007059), and cell cycle control (GO: 0044770). Through rigorous selection of the lncRNA/circRNA-based ceRNA network, we demonstrated that the hub genes reside in UC-MSC- and CB-MNC-infused networks directed to the function of cell adhesion, motor transportation (Cdk13, Lrrn2), immune homeostasis balance, and autophagy (Homer3, Prkcd) relatively. Our studies illustrate the first comprehensive mRNA–miRNA–lncRNA and mRNA–miRNA–circRNA networks in stem cell-infused BPD model, which will be valuable in identifying reliable biomarkers or therapeutic targets for BPD pathogenesis and shed new light in the priming and conditioning of UC-MSCs or CB-MNCs in the treatment of neonatal lung injury.

Transcriptome analysis reveals transforming growth factor-β1 prevents extracellular matrix degradation and cell adhesion during the follicular-luteal transition in cows.

Ovarian angiogenesis is an extremely rapid process that occurs during the transition from follicle to corpus luteum (CL) and is crucial for reproduction. It is regulated by numerous factors including transforming growth factor-β1 (TGFB1). However, the regulatory mechanism of TGFB1 in ovarian angiogenesis is not fully understood. To address this, in this study we obtained high-throughput transcriptome analysis (RNA-seq) data from bovine luteinizing follicular cells cultured in a system mimicking angiogenesis and treated with TGFB1, and identified 455 differentially expressed genes (DEGs). Quantitative real-time PCR results confirmed the differential expression patterns of the 12 selected genes. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis identified that the MAPK and ErbB pathways, cell adhesion molecules (CAMs), and extracellular matrix (ECM)-receptor interactions may play pivotal roles in TGFB1-mediated inhibition of CL angiogenesis. TGFB1 phosphorylated ERK1/2 (MAPK1/3) and Akt, indicating that these pathways may play an important role in the regulation of angiogenesis. Several genes with specific functions in cell adhesion and ECM degradation were identified among the DEGs. In particular, TGFB1-induced upregulation of syndecan-1 (SDC1) and collagen type I alpha 1 chain (COL1A1) expression may contribute to the deposition of type I collagen in luteinizing follicular cells. These results indicate that TGFB1 inhibits cell adhesion and ECM degradation processes involving ERK1/2, ErbB, and PI3K/Akt signaling pathways, and leads to inhibition of angiogenesis during the follicular-luteal transition. Our results further reveal the molecular mechanisms underlying the actions of TGFB1 in early luteinization.

Altered gene expression in slc4a11\u2212/\u2212 mouse cornea highlights SLC4A11 roles

SLC4A11 is a H+/NH3/water transport protein, of corneal endothelial cells. SLC4A11 mutations cause congenital hereditary endothelial dystrophy and some cases of Fuchs endothelial corneal dystrophy. To probe SLC4A11’s roles, we compared gene expression in RNA from corneas of 17-week-old slc4a11−/− (n = 3) and slc4a11+/+ mice (n = 3) and subjected to RNA sequencing. mRNA levels for a subset of genes were also assessed by quantitative real-time reverse transcription PCR (qRT RT-PCR). Cornea expressed 13,173 genes, which were rank-ordered for their abundance. In slc4a11−/− corneas, 100 genes had significantly altered expression. Abundant slc14a1 expression, encoding the urea transporter UT-A, suggests a significant role in the cornea. The set of genes with altered expression was subjected to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses, revealing that alterations clustered into extracellular region, cytoskeleton, cell adhesion and plasma membrane functions. Gene expression changes further clustered into classes (with decreasing numbers of genes): cell fate and development, extracellular matrix and cell adhesion, cytoskeleton, ion homeostasis and energy metabolism. Together these gene changes confirm earlier suggestions of a role of SLC4A11 in ion homeostasis, energy metabolism, cell adhesion, and reveal an unrecognized SLC4A11 role in cytoskeletal organization.

The graft framework: Quantitative changes in cell wall matrix polysaccharides throughout the tomato graft union formation

Plant cell walls provide essential functions in cell recognition, differentiation, adhesion and wound responses. Therefore, it is tempting to hypothesize that cell walls play a key role in grafting, but to date there are no quantitative studies targeting on cell wall changes during grafting. The aim of this work was to investigate the dynamics of pectic and hemicellulosic polysaccharides at the graft junctions in tomato homografts throughout the first 12 days after grafting. Cell wall fractionation, combined with ATR-FTIR spectroscopy and gas-chromatography, evidenced a marked increase in pectin content and a decrease in the degree of methyl-esterification of homogalacturonan in scion and rootstock throughout grafting. Also, recovery of tightly-bound hemicelluloses decreased at late times after grafting suggesting an increase of cross-linked hemicelluloses along grafting. In addition, immuno-dot assays revealed an increase in xyloglucan and arabinogalactan proteins in the first days after grafting, pointing to a presumed role in tissue adhesion-cohesion.

Gene transcriptome analysis of nasal epithelial cells in chronic rhinosinusitis with nasal polyps

Objective: To identify the differentially expressed genes in nasal epithelial cells from chronic rhinosinusitis with nasal polyps (CRSwNP), and to analyze related genes which are involved in deficiency of nasal epithelial barrier in CRSwNP patients by analyzing the datasets download from the gene expression omnibus(GEO) database. Methods: The mRNA expression microarray data numbered GSE107624 (7 CRSwNP and 7 controls) and GSE69093 (13 CRSwNP and 11 controls) were downloaded from the publicly available GEO database. These two datasets were jointly analyzed to screen the differentially expressed genes in nasal epithelial cells of controls and CRSwNP patients. In the meanwhile, we further evaluated the function annotation and regulatory pathways of the differentially expressed genes. To further confirmed what we have observed, sinus tissues were collected from patients with CRSwNP (14 cases, 46.8±17.9 years) and uncinate process tissues were collected from patients with nasal septum deviation (7 cases, 23.4±2.3 years) as control group. The primary epithelial cells of nasal mucosa were cultured and the mRNA level of screened genes were measured by Q-PCR. SPSS 22.0 software was used to for statistical analysis. Results: GSE107624 dataset showed that there were 3 856 differentially genes in nasal epithelial cells between CRSwNP and control group, while there were 771 differentially expressed genes in GSE69093 dataset. Finally, 55 up-regulated genes and 3 down-regulated genes were noticed in nasal epithelial cells of CRSwNP patients in the two datasets. GO gene functional annotation analysis showed that SPTBN1, FNBP1L, VAPB and SNX1 were involved in cell adhesion function, MAP1B was participated in the formation of microtubule related complex. KEGG pathway enrichment analysis indicated that BAMBI and SIAH1 were involved in regulation of Wnt pathway, COL6A1 and EIF4E were involved in the regulation of PI3K-AKT pathway. String protein interaction network analysis assumed that MAP1B and VAPB were the core functional proteins. Among top 3 differentially expressed genes COL6A1, MAP1B and BAMBI, only MAP1B gene was increased in nasal epithelial cells of CRSwNP patients in comparison to controls. Conclusion: The increased MAP1B gene in epithelial cells of CRSwNP, as well as abnormal regulation of Wnt and PI3K-AKT signal pathways may mediate the barrier dysfunction in CRSwNP.

LPHN2 inhibits vascular permeability by differential control of endothelial cell adhesion.

Dynamic modulation of endothelial cell-to-cell and cell-to-extracellular matrix (ECM) adhesion is essential for blood vessel patterning and functioning. Yet the molecular mechanisms involved in this process have not been completely deciphered. We identify the adhesion G protein-coupled receptor (ADGR) Latrophilin 2 (LPHN2) as a novel determinant of endothelial cell (EC) adhesion and barrier function. In cultured ECs, endogenous LPHN2 localizes at ECM contacts, signals through cAMP/Rap1, and inhibits focal adhesion (FA) formation and nuclear localization of YAP/TAZ transcriptional regulators, while promoting tight junction (TJ) assembly. ECs also express an endogenous LPHN2 ligand, fibronectin leucine-rich transmembrane 2 (FLRT2), that prevents ECM-elicited EC behaviors in an LPHN2-dependent manner. Vascular ECs of lphn2a knock-out zebrafish embryos become abnormally stretched, display a hyperactive YAP/TAZ pathway, and lack proper intercellular TJs. Consistently, blood vessels are hyperpermeable, and intravascularly injected cancer cells extravasate more easily in lphn2a null animals. Thus, LPHN2 ligands, such as FLRT2, may be therapeutically exploited to interfere with cancer metastatic dissemination.