Phylogenetic analysis of the cadherin superfamily allows identification of six major subfamilies besides several solitary members

Interactions between insecticidal cry toxins and their receptors

Bacillus thuringiensis is a prominent, eco-friendly entomopathogenic bacterium used as a plant-incorporated toxin in genetically modified crops and as a stomach poison for insects in the form of spore formulations. Upon entering the alkaline environment of the insect gut, the toxin undergoes proteolytic breakdown, converting the protoxin into its activated form. The activated toxin then binds to receptors, forming pores that disrupt the ionic balance within the cell, ultimately leading to the insect's death. Alongside the four major receptors (Cadherin, ABCC, APN, and ALP), several other notable receptors are present on the Brush Border Membrane Vesicle of insects. Binding to these receptors plays a crucial role, and any mutations in these receptors can result in improper binding, leading to the development of resistant insect strains. This review explores the major receptors of insecticidal Cry toxins, the intricate interactions between toxins and receptors, receptor mutations, and strategies to overcome the resistance.

P-cadherin-dependent adhesions are required for single lumen formation and HGF-mediated cell protrusions during epithelial morphogenesis

During epithelial morphogenesis, in vivo, epithelial cells form cysts enclosing a single, hollow lumen and extend protrusions as a precursor for tubulogenesis. Cell-cell adhesions (e.g., cadherins) contribute to successful execution of these processes; while there are many different cadherins, one less studied cadherin in epithelial morphogenesis is P-cadherin (CDH3). Here, we investigated the role of CDH3 on successful lumen formation and cell protrusions, using three-dimensional cultures of Madin-Darby canine kidney (MDCK) and CDH3 knockout cell lines. We show that depletion of CDH3 leads to perturbations of hollow lumen formation associated with defects in cell protrusions and tubulogenesis, mediated by Rho/ROCK pathway. CDH3 knockout cells exert lower forces on the surrounding environment compared to wild-type cells, suggesting CDH3 acts as a mechanosensor for stable cell protrusion establishment. Together, our data suggest that CDH3 has an essential function during epithelial morphogenesis by contributing to lumen formation and cell protrusions.

Nervous system-wide analysis of all C. elegans cadherins reveals neuron-specific functions across multiple anatomical scales

Differential expression of cell adhesion proteins is a hallmark of cell-type diversity across the animal kingdom. Gene family-wide characterization of their organismal expression and function is, however, lacking. Using genome-engineered reporter alleles, we established an atlas of expression of the entire set of 12 cadherin gene family members in the nematode Caenorhabditis elegans, revealing differential expression across neuronal classes, a dichotomy between broadly and narrowly expressed cadherins, and several context-dependent temporal transitions in expression across development. Engineered mutant null alleles of cadherins were analyzed for defects in morphology, behavior, neuronal soma positions, neurite neighborhood topology and fasciculation, and localization of synapses in many parts of the nervous system. This analysis revealed a restricted pattern of neuronal differentiation defects at discrete subsets of anatomical scales, including a novel role of cadherins in experience-dependent electrical synapse formation. In total, our analysis results in previously little explored perspectives on cadherin deployment and function.

β-Catenin localization in the ctenophore Mnemiopsis leidyi suggests an ancestral role in cell adhesion and nuclear function

BACKGROUND

The emergence of multicellularity in animals marks a pivotal evolutionary event, which was likely enabled by molecular innovations in the way cells adhere and communicate with one another. β-Catenin is significant to this transition due to its dual role as both a structural component in the cadherin-catenin complex and as a transcriptional coactivator involved in the Wnt/β-catenin signaling pathway. However, our knowledge of how this protein functions in ctenophores, one of the earliest diverging metazoans, is limited.

RESULTS

To study β-catenin function in the ctenophore Mnemiopsis leidyi, we generated affinity-purified polyclonal antibodies targeting Mlβ-catenin. We then used this tool to observe β-catenin protein localization in developing Mnemiopsis embryos. In this article, we provide evidence of consistent β-catenin protein enrichment at cell-cell interfaces in Mnemiopsis embryos. Additionally, we found β-catenin enrichment in some nuclei, particularly restricted to the oral pole around the time of gastrulation. The Mlβ-catenin affinity-purified antibodies now provide us with a powerful reagent to study the ancestral functions of β-catenin in cell adhesion and transcriptional regulation.

CONCLUSIONS

The localization pattern of embryonic Mlβ-catenin suggests that this protein had an ancestral role in cell adhesion and may have a nuclear function as well.

Canalization of circuit assembly by δ-protocadherins in the zebrafish optic tectum

Neurons are precisely and reproducibly assembled into complex networks during development. How genes collaborate to guide this assembly remains an enduring mystery. In humans, large numbers of genes have been implicated in neurodevelopmental disorders that are characterized by variable and overlapping phenotypes. The complexity of the brain, the large number of genes involved and the heterogeneity of the disorders makes understanding the relationships between genes, development and neural function challenging. Waddington suggested the concept of canalization to describe the role of genes in shaping developmental trajectories that lead to precise outcomes1. Here, we show that members of the δ-protocadherin family of homophilic adhesion molecules, Protocadherin-19 and Protocadherin-17, contribute to developmental canalization of visual circuit assembly in the zebrafish. We provided oriented visual stimuli to zebrafish larvae and performed in vivo 2-photon calcium imaging in the optic tectum. The latent dynamics resulting from the population activity were confined to a conserved manifold. Among different wild type larvae, these dynamics were remarkably similar, allowing quantitative comparisons within and among genotypes. In both Protocadherin-19 and Protocadherin-17 mutants, the latent dynamics diverged from wild type. Importantly, these deviations could be averaged away, suggesting that the loss of these adhesion molecules leads to stochastic phenotypic variability and introduced disruptions of circuit organization that varied among individual mutants. These results provide a specific, quantitative example of canalization in the development of a vertebrate neural circuit, and suggest a framework for understanding the observed variability in complex brain disorders.

Calcium-dependent adhesion protein CDH18, a potential biomarker for prognosis in uterine corpus endometrial carcinoma

Background

Uterine corpus endometrial carcinoma (UCEC) is one of the most common cancers in women, yet lacks specific and sensitive tumor markers for diagnosis, as traditional markers like CA125 show limited specificity. This study investigates the clinical significance and prognostic value of CDH18, a calcium-dependent adhesion protein linked to tumor progression, in UCEC.

Methods

Clinical data from UCEC patients were sourced from The Cancer Genome Atlas (TCGA) database. Pan-cancer analysis, differential expression examination, and survival analysis were conducted to investigate the differential expression of the calcium associated protein-CDH18 and its prognostic relevance. CDH18 mutations in UCEC were examined using the cBioPortal database. Additional analyses included functional enrichment, tumor mutational burden, tumor microenvironment (TME) estimates via ESTIMATE, and immune infiltration assessment to clarify CDH18's potential mechanisms in UCEC. Drug sensitivity testing was utilized to identify more suitable therapeutic options for patients. Immunofluorescence staining (IF) and Real-Time Polymerase Chain Reaction techniques (RT-PCR) confirmed CDH18 expression in UCEC tumor.

Results

CDH18 expression was markedly increased in UCEC and showed a significant association with poorer prognosis, which was confirmed by our IF and RT-PCR results. Thirteen mutation sites were identified, and survival analysis showed that patients with higher CDH18 expression had shorter overall survival. The expression of CDH18 was confirmed to be an independent predictor of overall survival by multivariate COX regression analysis. Additionally, a predictive nomogram model was developed to accurately forecast outcomes for individuals with UCEC. Correlation analysis revealed that CDH18 expression exhibited a negative correlation with CD8 T cell levels and a positive correlation with resting NK cell and macrophage M2 levels. In the group with high CDH18 expression, the IC50 values for (5Z)-7-Oxozeaenol, AG-014699, CEP-701, Mitomycin C, PD-0325901, PD-0332991, PHA-665752, SL 0101-1, and SN-38 were notably elevated.

Conclusion

CDH18 is a novel promising biomarker in UCEC, uniquely associating tumor progression, immune modulation, and chemotherapy resistance, offering enhanced prognostic accuracy and guiding individualized therapeutic strategies for improved patient outcomes.

The Lego hypothesis of tissue morphogenesis: stereotypic organization of parallel orientational cell adhesions for epithelial self-assembly

How tissues develop distinct structures remains poorly understood. We propose herein the Lego hypothesis of tissue morphogenesis, which states that during tissue morphogenesis, the topographical properties of cell surface adhesion molecules can be dynamically altered and polarised by regulating the spatiotemporal expression and localization of orientational cell adhesion (OCA) molecules cell-autonomously and non-cell-autonomously, thus modulating cells into unique Lego pieces for self-assembling into distinct cytoarchitectures. This concept can be exemplified by epithelial morphogenesis, in which cells are coalesced into a sheet by many types of adhesions. Among them, parallel OCAs (pOCAs) at the lateral cell membranes are essential for configuring cells in parallel. Major pOCAs include Na+/K+-ATPase-mediated adhesions, Crumbs-mediated adhesions, tight junctions, adherens junctions, and desmosomes. These pOCAs align in stereotypical orders along the apical-to-basal axis, and their absolute positioning is also regulated. Such spatial organization of pOCAs underlies proper epithelial morphogenesis. Thus, a key open question about tissue morphogenesis is how to regulate OCAs to make compatible adhesive cellular Lego pieces for tissue construction.

Transcriptome Analysis Reveals Equine Endometrium's Gene Expression Profile Around Embryo Fixation

BACKGROUND/OBJECTIVES

The success or failure of embryo fixation is crucial for embryo attachment and later development. As an epithelial chorioallantoic placenta-type animal, the horse has a special process of embryo implantation, and the mechanism of embryo fixation in horses is still unclear.

METHODS

In this study, the structural and transcriptomic characteristics of endometrial tissue from the fixed and nonfixed sides of 20-day gestation embryos in Mongolian horses were investigated to search for important genes and potential molecular markers associated with the fixation phase of equine embryos.

RESULTS

A comparison of the structures of the endometrial tissues of the two sides revealed that the endometrium on the fixed side presented distinctive features, which were characterized mainly by the development of glands on the fixed side compared with those on the nonfixed side. A total of 3987 differentially expressed genes were identified in the transcriptome, among which 1931 genes were highly expressed on the fixed side of the embryo, including CDH1, DRA, DQB, CLND2, BOLA-DQB, CLDN10, PTGER2, and PTGFR. The differentially expressed genes were enriched in biological processes such as cell adhesion, morphogenesis, NOD signaling, and vitamin uptake, as well as prostatic hormones.

CONCLUSIONS

These results suggest that equine embryo fixation may depend at least on the regulation of prostaglandins and the establishment of cellular connections. This provides a foundation for exploring the molecular mechanisms of key genes and pathways related to equine embryo fixation and offers new insights into feeding management and the monitoring of mares in the early stages of pregnancy.

Classical cadherins evolutionary constraints in primates is associated with their expression in the central nervous system

Classical cadherins (CDH) comprise a family of single-pass transmembrane glycoproteins that contribute to tissue morphogenesis by regulating cell-cell adhesion, cytoskeletal dynamics, and cell signaling. CDH are grouped into type I (CDH 1, 2, 3, 4 and 15) and type II (CDH 5, 6, 7, 8, 9, 10, 11, 12, 18, 20, 22 and 24), based on the folding of the cadherin binding domain involved in trans-dimer formation. CDH are exclusively found in metazoans, and the origin and expansion of the gene family coincide with the emergence of multicellularity and vertebrates respectively. This study examined the evolutionary changes of CDH orthologs in primates and the factors that influence selective pressure to investigate the varying constraints exerted among CDH. Pairwise comparisons of the number of amino acid substitutions and of the ratio of non-synonymous substitutions per non-synonymous sites (dN) over synonymous substitutions per synonymous sites (dS), show that CDH2, CDH4, and most type II CDH have been under significantly higher negative selective pressure as compared to CDH1, CDH3, CDH5 and CDH19. Evaluation of gene essentiality as determined by the effect of germline deletion on animal viability, morphogenic phenotype, and reproductive fitness, show no correlation with the with extent of negative selection observed on CDH. Spearman's correlation analysis shows a positive correlation between CDH expression levels (E) in mouse and human tissues and their rate of evolution (R), as observed in most proteins expressed on the cell surface. However, CDH expression in the CNS show a significant E-R negative correlation, indicating that the strong negative selection exerted on CDH2, CDH4, and most type II CDH is associated with their expression in the CNS. CDH participate in a variety of cellular processes in the CNS including neuronal migration and functional assembly of neural circuits, which could profoundly influence animal fitness. Therefore, our findings suggest that the unusually high negative selective pressure exerted on CDH2, CDH4 and most type II CDH is due to their role in CNS formation and function and may have contributed to shape the evolution of the CNS in primates.

Identification of epithelial-related artificial neural network prognostic models for the prediction of bladder cancer prognosis through comprehensive analysis of single-cell and bulk RNA sequencing

Background

Bladder cancer (BLCA) presents as a heterogeneous epithelial malignancy. Progress in the early detection and effective treatment of BLCA relies heavily on the identification of novel biomarkers. Therefore, the primary goal of this study is to pinpoint potential biomarkers for BLCA through the fusion of single-cell RNA sequencing and RNA sequencing assessments. Furthermore, the aim is to establish practical clinical prognostic models that can facilitate accurate categorization and individualized therapy for patients.

Methods

In this research, training sets were acquired from the TCGA database, whereas validation sets (GSE32894) and single-cell datasets (GSE135337) were extracted from the GEO database. Single-cell analysis was utilized to obtain characteristic subpopulations along with their associated marker genes. Subsequently, a novel BLCA subtype was identified within TCGA-BLCA. Furthermore, an artificial neural network prognostic model was constructed within the TCGA-BLCA cohort and subsequently verified utilizing a validation set. Two machine learning algorithms were employed to screen hub genes. QRT-qPCR was performed to detect the gene expression levels utilized in the construction of prognostic models across various cell lines. Additionally, the cMAP database and molecular docking were utilized for searching small molecule drugs.

Results

The results of single-cell analysis revealed the presence of epithelial cells in multiple subpopulations, with 1579 marker genes selected for subsequent investigations. Subsequently, four epithelial cell subtypes were identified within the TCGA-BLCA cohort. Notably, cluster A exhibited a significant survival advantage. Concurrently, an artificial neural network prognostic model comprising 17 feature genes was constructed, accurately stratifying patient risk. Patients categorized in the low-risk group demonstrated a considerable survival advantage. The ROC analysis suggested that the model has strong prognostic ability. Furthermore, the findings of the validation group align consistently with those from the training group. Two types of machine learning algorithms screened NFIC as hub genes. Forskolin, a small molecule drug that binds to NFIC, was identified by employing a cMAP database and molecular docking.

Conclusion

The analysis results supplement the research on the role of epithelial cells in BLCA. An artificial neural network prognostic model containing 17 characteristic genes demonstrates the capability to accurately stratify patient risk, thereby potentially improving clinical decision-making and optimizing personalized therapeutic approaches.

Adaptive Evolution and Functional Differentiation of Testis-Expressed Genes in Theria

Gene expression patterns differ in different tissues, and the expression pattern of genes in the mammalian testis is known to be extremely variable in different species. To clarify how the testis transcriptomic pattern has evolved in particular species, we examined the evolution of the adult testis transcriptome in Theria using 10 species: two marsupials (opossum and Tasmanian devil), six eutherian (placental) mammals (human, chimpanzee, bonobo, gorilla, rhesus macaque, and mouse), and two outgroup species (platypus and chicken). We show that 22 testis-expressed genes are marsupial-specific, suggesting their acquisition in the stem lineage of marsupials after the divergence from eutherians. Despite the time length of the eutherian stem lineage being similar to that of the marsupial lineage, acquisition of testis-expressed genes was not found in the stem lineage of eutherians; rather, their expression patterns differed by species, suggesting rapid gene evolution in the eutherian ancestors. Fifteen testis-expressed genes are therian-specific, and for three of these genes, the evolutionary tempo is markedly faster in eutherians than in marsupials. Our phylogenetic analysis of Rho GTPase-activating protein 28 (ARHGAP28) suggests the adaptive evolution of this gene in the eutherians, probably together with the expression pattern differentiation.

Dysregulated Cerebrospinal Fluid Proteome of Spinocerebellar Ataxia Type 2 and its Clinical Implications

BACKGROUND

Abnormalities in ataxin-2 associated with spinocerebellar ataxia type 2 (SCA2) may lead to widespread disruptions in the proteome. This study was performed to identify dysregulated proteome in SCA2 and to explore its clinical-radiological correlations.

METHODS

Cerebrospinal fluid (CSF) samples from 21 genetically confirmed SCA2 were subjected to shotgun proteome analysis using mass spectrometry (MS) and tandem mass tag (TMT)-based multiplexing. Proteins with at least 1.5-fold change in abundance were identified. Their relative abundance was measured using parallel reaction monitoring (PRM) and correlated against disease-related factors.

RESULTS

Eleven proteins were significantly upregulated in SCA2. They belonged to the family of cell adhesion molecules and granins. Their fold changes showed significant clinical, genetic, and radiological correlations.

CONCLUSIONS

Significant dysregulation of CSF proteome is seen in SCA2. The dysregulated protein may have potential use in clinical evaluation of patients with SCA2.

Structural basis of molecular recognition among classical cadherins mediating cell adhesion

Cadherins are type-I membrane glycoproteins that primarily participate in calcium-dependent cell adhesion and homotypic cell sorting in various stages of embryonic development. Besides their crucial role in cellular and physiological processes, increasing studies highlight their involvement in pathophysiological functions ranging from cancer progression and metastasis to being entry receptors for pathogens. Cadherins mediate these cellular processes through homophilic, as well as heterophilic interactions (within and outside the superfamily) by their membrane distal ectodomains. This review provides an in-depth structural perspective of molecular recognition among type-I and type-II classical cadherins. Furthermore, this review offers structural insights into different dimeric assemblies like the 'strand-swap dimer' and 'X-dimer' as well as mechanisms relating these dimer forms like 'two-step adhesion' and 'encounter complex'. Alongside providing structural details, this review connects structural studies to bond mechanics merging crystallographic and single-molecule force spectroscopic findings. Finally, the review discusses the recent discoveries on dimeric intermediates that uncover prospects of further research beyond two-step adhesion.

Stepwise modulation of apical orientational cell adhesions for vertebrate neurulation

Neurulation transforms the neuroectoderm into the neural tube. This transformation relies on reorganising the configurational relationships between the orientations of intrinsic polarities of neighbouring cells. These orientational intercellular relationships are established, maintained, and modulated by orientational cell adhesions (OCAs). Here, using zebrafish (Danio rerio) neurulation as a major model, we propose a new perspective on how OCAs contribute to the parallel, antiparallel, and opposing intercellular relationships that underlie the neural plate-keel-rod-tube transformation, a stepwise process of cell aggregation followed by cord hollowing. We also discuss how OCAs in neurulation may be regulated by various adhesion molecules, including cadherins, Eph/Ephrins, Claudins, Occludins, Crumbs, Na+ /K+ -ATPase, and integrins. By comparing neurulation among species, we reveal that antiparallel OCAs represent a conserved mechanism for the fusion of the neural tube. Throughout, we highlight some outstanding questions regarding OCAs in neurulation. Answers to these questions will help us understand better the mechanisms of tubulogenesis of many tissues.

The immunolocalization of cadherins and beta-catenin in the cervix and vagina of cycling cows

The adherens junctions (AJs) maintain the epithelial cell layers' structural integrity and barrier function. AJs also play a vital role in various biological and pathological processes. AJs perform these functions through the cadherin-catenin adhesion complex. This study investigated the presence, cell-specific localization, and temporal distribution of AJ components such as classical type I cadherins and beta-catenin in the cow cervix and vagina during the estrous cycle. Immunohistochemistry and Western blot analysis results demonstrated that beta-catenin and epithelial (E)-, neural (N)-, and placental (P)-cadherins are expressed in the cow cervix and vagina during the estrous cycle. These adhesion molecules were localized in the membrane and cytoplasm of the ciliated and non-ciliated cervical cells and the stratified vaginal epithelial cells. Positive immunostaining for P-, N-cadherin, and beta-catenin was also observed in the vascular endothelial cells of the cervical and vaginal stroma. Quantitative immunohistochemistry examinations revealed that in the cervical and vaginal epithelia, P-cadherin's optical density values (ODv) were the highest; in contrast, the N-cadherin ODv were the lowest. The ODv of P-cadherin and beta-catenin in the cervical epithelium and E-cadherin in the vagina were significantly higher in the luteal phase versus the follicular phase of the estrous cycle. Furthermore, the ODv of P-cadherin, N-cadherin, and beta-catenin in the cervix's central and peripheral epithelial regions were different during the estrous cycle. These findings indicate that classical cadherins and beta-catenin in the cervix and vagina exhibit cell- and tissue-specific expression patterns under the influence of estrogen and progesterone hormones during the estrous cycle.

KRT18 regulates trophoblast cell migration and invasion which are essential for embryo implantation

Female infertility is a worldwide concern that impacts the quality of life and well-being of affected couples. Failure of embryo implantation is a major cause of early pregnancy loss and is precisely regulated by a programmed molecular mechanism. Recent studies have shown that proper trophoblast adhesion and invasion are essential for embryo implantation. However, the potential regulatory mechanism involved in trophoblast adhesion and invasion has yet to be fully elucidated. KRT18 has been reported to play a critical role in early embryonic development, but its physiological function in embryo implantation remains unclear. In the present study, we revealed that KRT18 was highly expressed in trophoblast cells and that knockdown of KRT18 in mouse embryos inhibited embryo adhesion and implantation. In vitro experiments further showed that silencing KRT18 disturbed trophoblast migration and invasion. More importantly, we provide evidence that KRT18 directly binds to and stabilizes cell surface E-cadherin in trophoblast cells through microscale thermophoresis (MST) analysis and molecular biology experiments. In brief, our data reveal that KRT18, which is highly expressed in trophoblast cells, plays an important role in the regulation of trophoblast invasion and adhesion during embryo implantation by directly binding to E-cadherin.

Molecular mechanism of VE-cadherin in regulating endothelial cell behaviour during angiogenesis

Vascular endothelial (VE)-cadherin, an endothelium-specific adhesion protein, is found in the junctions between endothelial cells (ECs). It's crucial to maintain the homogeneity of ECs. Keeping and controlling the contact between ECs is essential. In addition to its adhesive function, VE-cadherin plays important roles in vascular development, permeability, and tumour angiogenesis. Signal transfer, cytoskeletal reconstruction, and contractile integrating, which are crucial for constructing and maintaining monolayer integrity as well as for repair and regeneration, are the foundation of endothelial cell (EC) junctional dynamics. The molecular basis of adhesion junctions (AJs), which are closely related and work with actin filaments, is provided by the VE-cadherin-catenin complex. They can activate intracellular signals that drive ECs to react or communicate structural changes to junctions. An increasing number of molecules, including the vascular endothelial growth factor receptor 2 (VEGFR2) and vascular endothelial protein tyrosine phosphatase (VE-PTP), have been connected to VE-cadherin in addition to the conventional VE-cadherin-catenin complex. This review demonstrates significant progress in our understanding of the molecular mechanisms that affect VE-cadherin's function in the regulation of EC behaviour during angiogenesis. The knowledge of the molecular processes that control VE-cadherin's role in the regulation of EC behaviour during angiogenesis has recently advanced, as shown in this review.

Respiratory Syncytial Virus Infection Does Not Induce Epithelial-Mesenchymal Transition

Respiratory syncytial virus (RSV) infection does not cause severe disease in most of us despite suffering from multiple RSV infections during our lives. However, infants, young children, older adults, and immunocompromised patients are unfortunately vulnerable to RSV-associated severe diseases. A recent study suggested that RSV infection causes cell expansion, resulting in bronchial wall thickening in vitro. Whether the virus-induced changes in the lung airway resemble epithelial-mesenchymal transition (EMT) is still unknown. Here, we report that RSV does not induce EMT in three different in vitro lung models: the epithelial A549 cell line, primary normal human bronchial epithelial cells, and pseudostratified airway epithelium. We found that RSV increases the cell surface area and perimeter in the infected airway epithelium, which is distinct from the effects of a potent EMT inducer, transforming growth factor β1 (TGF-β1), driving cell elongation-indicative of cell motility. A genome-wide transcriptome analysis revealed that both RSV and TGF-β1 have distinct modulation patterns of the transcriptome, which suggests that RSV-induced changes are distinct from EMT. IMPORTANCE We have previously shown that RSV infects ciliated cells on the apical side of the lung airway. RSV-induced cytoskeletal inflammation contributes to an uneven increase in the height of the airway epithelium, resembling noncanonical bronchial wall thickening. RSV infection changes epithelial cell morphology by modulating actin-protein 2/3 complex-driven actin polymerization. Therefore, it is prudent to investigate whether RSV-induced cell morphological changes contribute to EMT. Our data indicate that RSV does not induce EMT in at least three different epithelial in vitro models: an epithelial cell line, primary epithelial cells, and pseudostratified bronchial airway epithelium.

Cell death signaling in Anopheles gambiae initiated by Bacillus thuringiensis Cry4B toxin involves Na+/K+ ATPase

Identifying the mechanisms by which bacterial pathogens kill host cells is fundamental to understanding how to control and prevent human and animal disease. In the case of Bacillus thuringiensis (Bt), such knowledge is critical to using the bacterium to kill insect vectors that transmit human and animal disease. For the Cry4B toxin produced by Bt, its capacity to kill Anopheles gambiae, the primary mosquito vector of malaria, is the consequence of a variety of signaling activities. We show here that Cry4B, acting as first messenger, binds specifically to the bitopic cadherin BT-R3 G-protein-coupled receptor (GPCR) localized in the midgut of A. gambiae, activating the downstream second messenger cyclic adenosine monophosphate (cAMP). The direct result of the Cry4B-BT-R3 binding is the release of αs from the heterotrimeric αβγ-G-protein complex and its activation of adenylyl cyclase (AC). The upshot is an increased level of cAMP, which activates protein kinase A (PKA). The functional impact of cAMP-PKA signaling is the stimulation of Na+/K+-ATPase (NKA) which serves as an Na+/K+ pump to maintain proper gradients of extracellular Na+ and intracellular K+. Increased level of cAMP amplifies NKA and upsets normal ion concentration gradients. NKA, as a scaffolding protein, accelerates the first messenger signal to the nucleus, generating additional BT-R3 molecules and promoting their exocytotic trafficking to the cell membrane. Accumulation of BT-R3 on the cell surface facilitates recruitment of additional toxin molecules which, in turn, amplify the original signal in a cascade-like manner. This report provides the first evidence of a bacterial toxin using NKA via AC/PKA signaling to execute cell death.

What do we know about blood-testis barrier? current understanding of its structure and physiology

Blood-testis barrier (BTB) creates a particular compartment in the seminiferous epithelium. Contacting Sertoli cell-Sertoli cell plasma membranes possess specialized junction proteins which present a complex dynamic of formation and dismantling. Thus, these specialized structures facilitate germ cell movement across the BTB. Junctions are constantly rearranged during spermatogenesis while the BTB preserves its barrier function. Imaging methods are essential to studying the dynamic of this sophisticated structure in order to understand its functional morphology. Isolated Sertoli cell cultures cannot represent the multiple interactions of the seminiferous epithelium and in situ studies became a fundamental approach to analyze BTB dynamics. In this review, we discuss the contributions of high-resolution microscopy studies to enlarge the body of morphofunctional data to understand the biology of the BTB as a dynamic structure. The first morphological evidence of the BTB was based on a fine structure of the junctions, which was resolved with Transmission Electron Microscopy. The use of conventional Fluorescent Light Microscopy to examine labelled molecules emerged as a fundamental technique for elucidating the precise protein localization at the BTB. Then laser-scanning confocal microscopy allowed the study of three-dimensional structures and complexes at the seminiferous epithelium. Several junction proteins, like the transmembrane, scaffold and signaling proteins, were identified in the testis using traditional animal models. BTB morphology was analyzed in different physiological conditions as the spermatocyte movement during meiosis, testis development, and seasonal spermatogenesis, but also structural elements, proteins, and BTB permeability were studied. Under pathological, pharmacological, or pollutant/toxic conditions, there are significant studies that provide high-resolution images which help to understand the dynamic of the BTB. Notwithstanding the advances, further research using new technologies is required to gain information on the BTB. Super-resolution light microscopy is needed to provide new research with high-quality images of targeted molecules at a nanometer-scale resolution. Finally, we highlight research areas that warrant future studies, pinpointing new microscopy approaches and helping to improve our ability to understand this barrier complexity.

3D Chromatin Architecture Re-Wiring at the CDH3/CDH1 Loci Contributes to E-Cadherin to P-Cadherin Expression Switch in Gastric Cancer

Cadherins are cell-cell adhesion molecules, fundamental for cell architecture and polarity. E-cadherin to P-cadherin switch can rescue adherens junctions in epithelial tumours. Herein, we disclose a mechanism for E-cadherin to P-cadherin switch in gastric cancers. CDH1 and CDH3 mRNA expression was obtained from 42 gastric tumours' RNA-seq data. CRISPR-Cas9 was used to knock out CDH1 and a putative regulatory element. CDH1-depleted and parental cells were submitted to proteomics and enrichment GO terms analysis; ATAC-seq/4C-seq with a CDH1 promoter viewpoint to assess chromatin accessibility and conformation; and RT-PCR/flow cytometry to assess CDH1/E-cadherin and CDH3/P-cadherin expression. In 42% of gastric tumours analysed, CDH1 to CDH3 switch was observed. CDH1 knockout triggered CDH1/E-cadherin complete loss and CDH3/P-cadherin expression increase at plasma membrane. This switch, likely rescuing adherens junctions, increased cell migration/proliferation, commonly observed in aggressive tumours. E- to P-cadherin switch accompanied increased CDH1 promoter interactions with CDH3-eQTL, absent in normal stomach and parental cells. CDH3-eQTL deletion promotes CDH3/CDH1 reduced expression. These data provide evidence that loss of CDH1/E-cadherin expression alters the CDH3 locus chromatin conformation, allowing a CDH1 promoter interaction with a CDH3-eQTL, and promoting CDH3/P-cadherin expression. These data highlight a novel mechanism triggering E- to P-cadherin switch in gastric cancer.

Targeting N-cadherin (CDH2) and the malignant bone marrow microenvironment in acute leukaemia

This review discusses current research on acute paediatric leukaemia, the leukaemic bone marrow (BM) microenvironment and recently discovered therapeutic opportunities to target leukaemia-niche interactions. The tumour microenvironment plays an integral role in conferring treatment resistance to leukaemia cells, this poses as a key clinical challenge that hinders management of this disease. Here we focus on the role of the cell adhesion molecule N-cadherin (CDH2) within the malignant BM microenvironment and associated signalling pathways that may bear promise as therapeutic targets. Additionally, we discuss microenvironment-driven treatment resistance and relapse, and elaborate the role of CDH2-mediated cancer cell protection from chemotherapy. Finally, we review emerging therapeutic approaches that directly target CDH2-mediated adhesive interactions between the BM cells and leukaemia cells.

Molecular mechanism underlying the increased risk of colorectal cancer metastasis caused by single nucleotide polymorphisms in LI-cadherin gene

LI-cadherin is a member of the cadherin superfamily. LI-cadherin mediates Ca2+-dependent cell-cell adhesion through homodimerization. A previous study reported two single nucleotide polymorphisms (SNPs) in the LI-cadherin-coding gene (CDH17). These SNPs correspond to the amino acid changes of Lys115 to Glu and Glu739 to Ala. Patients with colorectal cancer carrying these SNPs are reported to have a higher risk of lymph node metastasis than patients without the SNPs. Although proteins associated with metastasis have been identified, the molecular mechanisms underlying the functions of these proteins remain unclear, making it difficult to develop effective strategies to prevent metastasis. In this study, we employed biochemical assays and molecular dynamics (MD) simulations to elucidate the molecular mechanisms by which the amino acid changes caused by the SNPs in the LI-cadherin-coding gene increase the risk of metastasis. Cell aggregation assays showed that the amino acid changes weakened the LI-cadherin-dependent cell-cell adhesion. In vitro assays demonstrated a decrease in homodimerization tendency and MD simulations suggested an alteration in the intramolecular hydrogen bond network by the mutation of Lys115. Taken together, our results indicate that the increased risk of lymph node metastasis is due to weakened cell-cell adhesion caused by the decrease in homodimerization tendency.

Cell cycle-dependent palmitoylation of protocadherin 7 by ZDHHC5 promotes successful cytokinesis

Cell division requires dramatic reorganization of the cell cortex, which is primarily driven by the actomyosin network. We previously reported that protocadherin 7 (PCDH7) gets enriched at the cell surface during mitosis, which is required to build up the full mitotic rounding pressure. Here, we report that PCDH7 interacts with and is palmitoylated by the palmitoyltransferase, ZDHHC5. PCDH7 and ZDHHC5 colocalize at the mitotic cell surface and translocate to the cleavage furrow during cytokinesis. The localization of PCDH7 depends on the palmitoylation activity of ZDHHC5. Silencing PCDH7 increases the percentage of multinucleated cells and the duration of mitosis. Loss of PCDH7 expression correlates with reduced levels of active RhoA and phospho-myosin at the cleavage furrow. This work uncovers a palmitoylation-dependent translocation mechanism for PCDH7, which contributes to the reorganization of the cortical cytoskeleton during cell division.

RSV infection does not induce EMT

Respiratory syncytial virus (RSV) infection does not cause severe disease in most of us despite suffering from multiple RSV infections in our lives. However, infants, young children, older adults, and immunocompromised patients are unfortunately vulnerable to RSV-associated severe diseases. A recent study suggested that RSV infection causes cell expansion, resulting in bronchial wall thickening in vitro. Whether the virus-induced changes in the lung airway resemble epithelial-mesenchymal transition (EMT) is still unknown. Here, we report that RSV does not induce EMT in three different in vitro lung models: the epithelial A549 cell line, primary normal human bronchial epithelial cells, and pseudostratified airway epithelium. We found that RSV increases the cell surface area and perimeter in the infected airway epithelium, which is distinct from the effects of a potent EMT inducer, TGF-β1-driven cell elongation-indicative of cell motility. A genome-wide transcriptome analysis revealed that both RSV and TGF-β1 have distinct modulation patterns of the transcriptome, which suggests that RSV-induced changes are distinct from EMT.

Cell-adhesion Molecules as Key Mechanisms of Tumor Invasion: The Case of Breast Cancer

Cancer is a major health problem worldwide and the second leading cause of death following cardiovascular diseases. Breast cancer is the leading cause of mortality and morbidity among women and one of the most common malignant neoplasms prompt to metastatic disease. In the present review, the mechanisms of the major cell adhesion molecules involved in tumor invasion are discussed, focusing on the case of breast cancer. A non-systematic updated revision of the literature was performed in order to assemble information regarding the expression of the adhesion cell molecules associated with metastasis.

Overview of junctional complexes during mammalian early embryonic development

Cell-cell junctions form strong intercellular connections and mediate communication between blastomeres during preimplantation embryonic development and thus are crucial for cell integrity, polarity, cell fate specification and morphogenesis. Together with cell adhesion molecules and cytoskeletal elements, intercellular junctions orchestrate mechanotransduction, morphokinetics and signaling networks during the development of early embryos. This review focuses on the structure, organization, function and expressional pattern of the cell-cell junction complexes during early embryonic development. Understanding the importance of dynamic junction formation and maturation processes will shed light on the molecular mechanism behind developmental abnormalities of early embryos during the preimplantation period.

Cell sorting in vitro and in vivo: How are cadherins involved?

Animal tissues are composed of heterogenous cells, and their sorting into different compartments of the tissue is a pivotal process for organogenesis. Cells accomplish sorting by themselves-it is well known that singly dispersed cells can self-organize into tissue-like structures in vitro. Cell sorting is regulated by both biochemical and physical mechanisms. Adhesive proteins connect cells together, selecting particular partners through their specific binding properties, while physical forces, such as cell-cortical tension, control the cohesiveness between cells and in turn cell assembly patterns in mechanical ways. These processes cooperate in determining the overall cell sorting behavior. This article focuses on the 'cadherin' family of adhesion molecules as a biochemical component of cell-cell interactions, addressing how they regulate cell sorting by themselves or by cooperating with other factors. New ideas beyond the classical models of cell sorting are also discussed.

On the formation of ordered protein assemblies in cell-cell interfaces

Crystal structures of many cell-cell adhesion receptors reveal the formation of linear "molecular zippers" comprising an ordered one-dimensional array of proteins that form both intercellular (trans) and intracellular (cis) interactions. The clustered protocadherins (cPcdhs) provide an exemplar of this phenomenon and use it as a basis of barcoding of vertebrate neurons. Here, we report both Metropolis and kinetic Monte Carlo simulations of cPcdh zipper formation using simplified models of cPcdhs that nevertheless capture essential features of their three-dimensional structure. The simulations reveal that the formation of long zippers is an implicit feature of cPcdh structure and is driven by their cis and trans interactions that have been quantitatively characterized in previous work. Moreover, in agreement with cryo-electron tomography studies, the zippers are found to organize into two-dimensional arrays even in the absence of attractive interactions between individual zippers. Our results suggest that the formation of ordered two-dimensional arrays of linear zippers of adhesion proteins is a common feature of cell-cell interfaces. From the perspective of simulations, they demonstrate the importance of a realistic depiction of adhesion protein structure and interactions if important biological phenomena are to be properly captured.

Non-muscle invasive bladder cancer biomarkers beyond morphology

Non-muscle invasive bladder cancer (NMIBC) still represents a challenge in decision-making and clinical management since prognostic and predictive biomarkers of response to treatment are still under investigation. In addition to the risk factors defined by EORTC guidelines, histological features have also been considered key variables able to impact on recurrence and progression in bladder cancer. Conversely, the role of genomic rearrangements or expression of specific proteins at tissue level need further assessment in NMIBC. As with muscle-invasive cancer, NMIBC is a heterogeneous disease, characterized by genomic instability, varying rates of mutation and a wide range of protein tissue expression. In this Review, we summarized the recent evidence on prognostic and predictive tissue biomarkers in NMIBC, beyond morphological parameters, outlining how they could affect tumor biology and consequently its behavior during clinical care. Our aim was to facilitate clinical evaluation of promising biomarkers that may be employed to better stratify patients. We described the most common molecular events and immunohistochemical protein expressions linked to recurrence and progression. Moreover, we discussed the link between available treatments and molecular drivers that could be predictive of clinical response. In conclusion, we foster further investigations with particular focus on immunohistochemical evaluation of tissue biomarkers, a promising and cost-effective tool for daily practice.

Expression of cadherins and some connective tissue components in cow uterus and placenta during pregnancy

The implantation and placental development processes are regulated with cell adhesion molecules and remodeling of the maternal endometrium's extracellular matrices (ECM) and fetal chorion. This study aimed to investigate the distribution and localization of some classical cadherins (E-, N-, and P-cadherins) and extracellular matrix components collagen type 5α1, fibronectin, and laminin in the cow placentomes during pregnancy using immunohistochemical and Western blotting analyses. The study results confirmed the expression of E- and P-cadherins, collagen type Vα1 (COLVα1), fibronectin, and laminin in the cow placentomes, but not N-cadherin. Throughout the pregnancy, E- and P- cadherins, COLVα1, and laminin were localized in the luminal and glandular epithelium of the inter-caruncular endometrium, caruncular epithelium, and the uninucleate (UNCs) and binucleate trophoblast giant cells (BNCs/TGCs). E- cadherin immunoreactivity in the first pregnancy period was strong in the UNCs while moderate in the BNCs/TGCs. However, it was weak in both trophoblast in the second and third pregnancy periods. In the fetal trophoblasts, P- cadherin and laminin immunostainings were more intense in the BNCs/TGCs than UNCs. The fetal and maternal stromal cells were also positive for P- cadherin, COLVα1, fibronectin, and laminin. The immunostaining intensity of COLVα1 and fibronectin in the stromal extracellular matrix of the placentomes decreased as the pregnancy progressed. The endothelia of fetal and maternal vessels were positive for all proteins. The presence and distinct localization of cadherins and ECM proteins in the cow placentome components support the role of these molecules in regulating placental cell growth, migration, and matrix production during pregnancy.

Relationship between serum cadherin 6 and 11 levels and severe and early-onset preeclampsia: A pilot study

Objective:

Preeclampsia is a highly morbid disease of placental origin, life-threatening condition for both a pregnant woman and her fetus. Cadherin 6 and 11 are adhesion molecules that play an important role in trophoblastic development and placentation. In our study, we investigated the change in serum cadherin 6 and 11 levels in pregnant women with preeclampsia.

Materials and Methods:

Pregnant women with preeclampsia were selected and compared with healthy women (as a control group) for a one-year study. The serum alanine aminotransferase, aspartate aminotransferase, and cadherin levels 6 and 11 of participants were analyzed and compared.

Results:

A total of 189 pregnant women were subdivided into 2 groups as preeclamptic (n=94) and women with healthy pregnancy (n=95). The cadherin 6 and cadherin 11 levels of the preeclamptic patients were significantly higher than those in the control group (p=0.001), and they were found to be significantly higher mainly in patients with early-onset and severe preeclampsia group (p=0.001). The cut-off cadherin 6 and 11 values for severe preeclampsia were found as 98.174 ng/mL and 1.92 ng/mL; with sensitivity of 88.3% and 84% respectively (p=0.001).

Conclusion:

The data analysis showed elevated serum cadherin 6 and 11 levels associated with the severity and early onset of pre-eclampsia. Serum cadherin 6 and 11 levels can be a candidate marker for the prediction of preeclampsia.

New Insights on the Regulatory Gene Network Disturbed in Central Areolar Choroidal Dystrophy-Beyond Classical Gene Candidates

Central areolar choroidal dystrophy (CACD) is a rare hereditary disease that mainly affects the macula, resulting in progressive and usually profound visual loss. Being part of congenital retinal dystrophies, it may have an autosomal dominant or recessive inheritance and, until now, has no effective treatment. Given the shortage of genotypic information about the disease, this work systematically reviews the literature for CACD-causing genes. Three independent researchers selected 33 articles after carefully searching and filtering the Scielo, Pubmed, Lilacs, Web of Science, Scopus, and Embase databases. Mutations of six genes (PRPH2, GUCA1A, GUCY2D, CDHR1, ABCA4, and TTLL5) are implicated in the monogenic dominant inheritance of CACD. They are functionally related to photoreceptors (either in the phototransduction process, as in the case of GUCY2D, or the recovery of retinal photodegradation in photoreceptors for GUCA1A, or the formation and maintenance of specific structures within photoreceptors for PRPH2). The identified genetic variants do not explain all observed clinical features, calling for further whole-genome and functional studies for this disease. A network analysis with the CACD-related genes identified in the systematic review resulted in the identification of another 20 genes that may influence CACD onset and symptoms. Furthermore, an enrichment analysis allowed the identification of 13 transcription factors and 4 long noncoding RNAs interacting with the products of the previously mentioned genes. If mutated or dysregulated, they may be directly involved in CACD development and related disorders. More than half of the genes identified by bioinformatic tools do not appear in commercial gene panels, calling for more studies about their role in the maintenance of the retina and phototransduction process, as well as for a timely update of these gene panels.

Identification of Pax protein inhibitors that suppress target gene expression and cancer cell proliferation

The Pax family of developmental control genes are frequently deregulated in human disease. In the kidney, Pax2 is expressed in developing nephrons but not in adult proximal and distal tubules, whereas polycystic kidney epithelia or renal cell carcinoma continues to express high levels. Pax2 reduction in mice or cell culture can slow proliferation of cystic epithelial cells or renal cancer cells. Thus, inhibition of Pax activity may be a viable, cell-type-specific therapy. We designed an unbiased, cell-based, high-throughput screen that identified triazolo pyrimidine derivatives that attenuate Pax transactivation ability. We show that BG-1 inhibits Pax2-positive cancer cell growth and target gene expression but has little effect on Pax2-negative cells. Chromatin immunoprecipitation suggests that these inhibitors prevent Pax protein interactions with the histone H3K4 methylation complex at Pax target genes in renal cells. Thus, these compounds may provide structural scaffolds for kidney-specific inhibitors with therapeutic potential.

Epithelial to mesenchymal transition during mammalian neural crest cell delamination

Epithelial to mesenchymal transition (EMT) is a well-defined cellular process that was discovered in chicken embryos and described as "epithelial to mesenchymal transformation" [1]. During EMT, epithelial cells lose their epithelial features and acquire mesenchymal character with migratory potential. EMT has subsequently been shown to be essential for both developmental and pathological processes including embryo morphogenesis, wound healing, tissue fibrosis and cancer [2]. During the past 5 years, interest and study of EMT especially in cancer biology have increased exponentially due to the implied role of EMT in multiple aspects of malignancy such as cell invasion, survival, stemness, metastasis, therapeutic resistance and tumor heterogeneity [3]. Since the process of EMT in embryogenesis and cancer progression shares similar phenotypic changes, core transcription factors and molecular mechanisms, it has been proposed that the initiation and development of carcinoma could be attributed to abnormal activation of EMT factors usually required for normal embryo development. Therefore, developmental EMT mechanisms, whose timing, location, and tissue origin are strictly regulated, could prove useful for uncovering new insights into the phenotypic changes and corresponding gene regulatory control of EMT under pathological conditions. In this review, we initially provide an overview of the phenotypic and molecular mechanisms involved in EMT and discuss the newly emerging concept of epithelial to mesenchymal plasticity (EMP). Then we focus on our current knowledge of a classic developmental EMT event, neural crest cell (NCC) delamination, highlighting key differences in our understanding of NCC EMT between mammalian and non-mammalian species. Lastly, we highlight available tools and future directions to advance our understanding of mammalian NCC EMT.

Into the Tissues: Extracellular Matrix and Its Artificial Substitutes: Cell Signalling Mechanisms

The existence of orderly structures, such as tissues and organs is made possible by cell adhesion, i.e., the process by which cells attach to neighbouring cells and a supporting substance in the form of the extracellular matrix. The extracellular matrix is a three-dimensional structure composed of collagens, elastin, and various proteoglycans and glycoproteins. It is a storehouse for multiple signalling factors. Cells are informed of their correct connection to the matrix via receptors. Tissue disruption often prevents the natural reconstitution of the matrix. The use of appropriate implants is then required. This review is a compilation of crucial information on the structural and functional features of the extracellular matrix and the complex mechanisms of cell-cell connectivity. The possibilities of regenerating damaged tissues using an artificial matrix substitute are described, detailing the host response to the implant. An important issue is the surface properties of such an implant and the possibilities of their modification.

Protein O-mannosylation across kingdoms and related diseases: From glycobiology to glycopathology

The post-translational glycosylation of proteins by O-linked α-mannose is conserved from bacteria to humans. Due to advances in high-throughput mass spectrometry-based approaches, a variety of glycoproteins are identified to be O-mannosylated. Various proteins with O-mannosylation are involved in biological processes, providing essential necessity for proper growth and development. In this review, we summarize the process and regulation of O-mannosylation. The multi-step O-mannosylation procedures are quite dynamic and complex, especially when considering the structural and functional inspection of the involved enzymes. The widely studied O-mannosylated proteins in human include α-Dystroglycan (α-DG), cadherins, protocadherins, and plexin, and their aberrant O-mannosylation are associated with many diseases. In addition, O-mannosylation also contributes to diverse functions in lower eukaryotes and prokaryotes. Finally, we present the relationship between O-mannosylation and gut microbiota (GM), and elucidate that O-mannosylation in microbiome is of great importance in the dynamic balance of GM. Our study provides an overview of the processes of O-mannosylation in mammalian cells and other organisms, and also associated regulated enzymes and biological functions, which could contribute to the understanding of newly discovered O-mannosylated glycoproteins.

Custom Next-Generation Sequencing Identifies Novel Mutations Expanding the Molecular and clinical spectrum of isolated Hearing Impairment or along with defects of the retina, the thyroid, and the kidneys

Background

In the Tunisian population, the molecular analysis of hearing impairment remains based on conventional approaches, which makes the task laborious and enormously expensive. Exploration of the etiology of Hearing Impairment and the early diagnosis of causal mutations by next‐generation sequencing help significantly alleviate social and economic problems.

Methods

We elaborated a custom SureSelect^QXT panel for next‐generation sequencing of the coding sequences of 42 genes involved in isolated hearing impairment or along with defects of the retina, the thyroid, and the kidneys.

Results

We report eight pathogenic variants, four of which are novel in patients with isolated hearing impairment, hearing impairment, and renal tubular acidosis, Usher syndrome and Pendred syndrome. Functional studies using molecular modeling showed the severe impact of the novel missense mutations on the concerned proteins. Basically, we identified mutations in nuclear as well as mitochondrial genes in a Tunisian family with isolated hearing impairment, which explains definitely the phenotype detected since 2006.

Conclusion

Our results expanded the mutation spectrum and genotype‒phenotype correlation of isolated and syndromic hearing loss and also emphasized the importance of combining both targeted next‐generation sequencing and detailed clinical evaluation to elaborate a more accurate diagnosis for hearing impairment and related phenotypes especially in North African populations.

Altering Cell-Cell Interaction in Prenatal Alcohol Exposure Models: Insight on Cell-Adhesion Molecules During Brain Development

Alcohol exposure during pregnancy disrupts the development of the brain and produces long lasting behavioral and cognitive impairments collectively known as Fetal Alcohol Spectrum Disorders (FASDs). FASDs are characterized by alterations in learning, working memory, social behavior and executive function. A large body of literature using preclinical prenatal alcohol exposure models reports alcohol-induced changes in architecture and activity in specific brain regions affecting cognition. While multiple putative mechanisms of alcohol’s long-lasting effects on morphology and behavior have been investigated, an area that has received less attention is the effect of alcohol on cell adhesion molecules (CAMs). The embryo/fetal development represents a crucial period for Central Nervous System (CNS) development during which the cell-cell interaction plays an important role. CAMs play a critical role in neuronal migration and differentiation, synaptic organization and function which may be disrupted by alcohol. In this review, we summarize the physiological structure and role of CAMs involved in brain development, review the current literature on prenatal alcohol exposure effects on CAM function in different experimental models and pinpoint areas needed for future study to better understand how CAMs may mediate the morphological, sensory and behavioral outcomes in FASDs.

Direct Interaction of Sox10 With Cadherin-19 Mediates Early Sacral Neural Crest Cell Migration: Implications for Enteric Nervous System Development Defects

BACKGROUND AND AIMS

The enteric nervous system, which regulates many gastrointestinal functions, is derived from neural crest cells (NCCs). Defective NCC migration during embryonic development may lead to enteric neuropathies such as Hirschsprung's disease (hindgut aganglionosis). Sox10 is known to be essential for cell migration but downstream molecular events regulating early NCC migration have not been fully elucidated. This study aimed to determine how Sox10 regulates migration of sacral NCCs toward the hindgut using Dominant megacolon mice, an animal model of Hirschsprung's disease with a Sox10 mutation.

METHODS

We used the following: time-lapse live cell imaging to determine the migration defects of mutant sacral NCCs; genome-wide microarrays, site-directed mutagenesis, and whole embryo culture to identify Sox10 targets; and liquid chromatography and tandem mass spectrometry to ascertain downstream effectors of Sox10.

RESULTS

Sacral NCCs exhibited retarded migration to the distal hindgut in Sox10-null embryos with simultaneous down-regulated expression of cadherin-19 (Cdh19). Sox10 was found to bind directly to the Cdh19 promoter. Cdh19 knockdown resulted in retarded sacral NCC migration in vitro and ex vivo, whereas re-expression of Cdh19 partially rescued the retarded migration of mutant sacral NCCs in vitro. Cdh19 formed cadherin-catenin complexes, which then bound to filamentous actin of the cytoskeleton during cell migration.

CONCLUSIONS

Cdh19 is a direct target of Sox10 during early sacral NCC migration toward the hindgut and forms cadherin-catenin complexes which interact with the cytoskeleton in migrating cells. Elucidation of this novel molecular pathway helps to provide insights into the pathogenesis of enteric nervous system developmental defects.

Novel mutations in PDE6A and CDHR1 cause retinitis pigmentosa in Pakistani families

AIM

To investigate the genetic basis of autosomal recessive retinitis pigmentosa (arRP) in two consanguineous/ endogamous Pakistani families.

METHODS

Whole exome sequencing (WES) was performed on genomic DNA samples of patients with arRP to identify disease causing mutations. Sanger sequencing was performed to confirm familial segregation of identified mutations, and potential pathogenicity was determined by predictions of the mutations' functions.

RESULTS

A novel homozygous frameshift mutation [NM_000440.2:c.1054delG, p. (Gln352Argfs*4); Chr5:g.149286886del (GRCh37)] in the PDE6A gene in an endogamous family and a novel homozygous splice site mutation [NM_033100.3:c.1168-1G>A, Chr10:g.85968484G>A (GRCh37)] in the CDHR1 gene in a consanguineous family were identified. The PDE6A variant p. (Gln352Argfs*4) was predicted to be deleterious or pathogenic, whilst the CDHR1 variant c.1168-1G>A was predicted to result in potential alteration of splicing.

CONCLUSION

This study expands the spectrum of genetic variants for arRP in Pakistani families.

Identification of Desmoglein-2 as a novel target of Helicobacter pylori HtrA in epithelial cells

BACKGROUND

High temperature requirement A (HtrA) is an active serine protease secreted by the group-I carcinogen Helicobacter pylori (H. pylori). The human cell adhesion protein and tumor suppressor E-cadherin (hCdh1) expressed on the surface of gastric epithelial cells was identified as the first HtrA substrate. HtrA-mediated hCdh1 cleavage and subsequent disruption of intercellular adhesions are considered as important steps in H. pylori pathogenesis. In this study, we performed a proteomic profiling of H. pylori HtrA (HpHtrA) to decipher the complex mechanism of H. pylori interference with the epithelial barrier integrity.

RESULTS

Using a proteomic approach we identified human desmoglein-2 (hDsg2), neuropilin-1, ephrin-B2, and semaphorin-4D as novel extracellular HpHtrA substrates and confirmed the well characterized target hCdh1. HpHtrA-mediated hDsg2 cleavage was further analyzed by in vitro cleavage assays using recombinant proteins. In infection experiments, we demonstrated hDsg2 shedding from H. pylori-colonized MKN28 and NCI-N87 cells independently of pathogen-induced matrix-metalloproteases or ADAM10 and ADAM17.

CONCLUSIONS

Characterizing the substrate specificity of HpHtrA revealed efficient hDsg2 cleavage underlining the importance of HpHtrA in opening intercellular junctions. Video Abstract.

High expression of oncogene cadherin-6 correlates with tumor progression and a poor prognosis in gastric cancer

BACKGROUND

Gastric cancer (GC) is one of the most common and fatal cancers worldwide. Effective biomarkers to aid the early diagnosis of GC, as well as predict the course of disease, are urgently needed. Hence, we explored the role and function of cadherin-6 (CDH6) in the diagnosis and prognosis of gastric cancer.

METHODS

The expression levels of CDH6 in cancerous and normal gastric tissue were analyzed using multiple public databases. Gene set enrichment analysis (GSEA) was performed using The Cancer Genome Atlas (TCGA) dataset. The diagnostic efficiency of CDH6 expression in GC patients was determined through receiver operating characteristic (ROC) curve analysis. The associations between clinical variables and CDH6 expression were evaluated statistically, and the prognostic factors for overall survival were analyzed by univariate and multivariate Cox regression. 44 GC tissue samples, 20 donor-matched adjacent normal tissue samples, and associated detailed clinical information, were collected from the Tianjin Medical University General Hospital. CDH6 expression levels were determined for further validation.

RESULTS

CDH6 was upregulated in GC samples compared to normal gastric tissue. Furthermore, GSEA identified the tricarboxylic acid (TCA) cycle, extracellular matrix (ECM) receptor interaction, glyoxylate and dicarboxylate metabolism, oxidative phosphorylation, and the pentose phosphate pathway as differentially enriched in GC tissue samples. According to the area under the ROC curve (AUC) values (AUC = 0.829 in the TCGA and 0.966 in the GSE54129 dataset), CDH6 expression was associated with high diagnostic efficacy. Patients with high CDH6 levels in their GC tissues had a higher T number (according to the TNM classification) and a worse prognosis than those with low CDH6 expression. Univariate and multivariate Cox regression analysis showed that CDH6 was an independent risk factor for overall survival (univariate: HR = 1.305, P = 0.002, multivariate: HR = 1.481, P < 0.001).

CONCLUSION

CDH6 was upregulated in GC, and high CDH6 expression was indicative of a higher T number and a worse prognosis. Therefore, CDH6 represents a potentially independent molecular biomarker for the diagnostic and prognostic prediction of GC.

The role of E-Cadherin expression in primary site of breast cancer

PURPOSE

The tumour's ability to metastasize is the major cause for fatal outcomes in cancer diseases. In breast cancer, aberrant E-Cadherin expression has been linked to invasiveness and poor prognosis.

METHOD

We assessed expression of E-Cadherin by immunohistochemistry in primary tumour tissue from 125 female breast cancer patients. Staining intensities were analysed using the immunoreactive score (IRS). We investigated E-Cadherin expression and its associations with clinicopathological parameters (age, tumour size, lymph node status, grade, hormone receptors, Her2 Status) as well as with recurrence and survival.

RESULTS

Increased, rather than aberrant E-Cadherin expression was found and was associated with poor outcome (p = 0.046). Our data show an association between elevated E-Cadherin in primary tumour tissue and an unfavourable negative prognosis in patients.

CONCLUSION

This association was somehow unexpected as loss of E-Cadherin has long been regarded as a prerequisite for development of invasiveness and metastases. Our findings support the notion that E-Cadherin promotes, rather than suppresses, development of metastasis and invasiveness.

Lobular Breast Cancer: Histomorphology and Different Concepts of a Special Spectrum of Tumors

Simple Summary

Invasive lobular breast cancer (ILC) is a special type of breast cancer (BC) that was first described in 1941. The diagnosis of ILC is made by microscopy of tumor specimens, which reveals a distinct morphology. This review recapitulates the developments in the microscopic assessment of ILC from 1941 until today. We discuss different concepts of ILC, provide an overview on ILC variants, and highlight advances which have contributed to a better understanding of ILC as a special histologic spectrum of tumors.

Abstract

Invasive lobular breast cancer (ILC) is the most common special histological type of breast cancer (BC). This review recapitulates developments in the histomorphologic assessment of ILC from its beginnings with the seminal work of Foote and Stewart, which was published in 1941, until today. We discuss different concepts of ILC and their implications. These concepts include (i) BC arising from mammary lobules, (ii) BC growing in dissociated cells and single files, and (iii) BC defined as a morpho-molecular spectrum of tumors with distinct histological and molecular characteristics related to impaired cell adhesion. This review also provides a comprehensive overview of ILC variants, their histomorphology, and differential diagnosis. Furthermore, this review highlights recent advances which have contributed to a better understanding of the histomorphology of ILC, such as the role of the basal lamina component laminin, the molecular specificities of triple-negative ILC, and E-cadherin to P-cadherin expression switching as the molecular determinant of tubular elements in CDH1-deficient ILC. Last but not least, we provide a detailed account of the tumor microenvironment in ILC, including tumor infiltrating lymphocyte (TIL) levels, which are comparatively low in ILC compared to other BCs, but correlate with clinical outcome. The distinct histomorphology of ILC clearly reflects a special tumor biology. In the clinic, special treatment strategies have been established for triple-negative, HER2-positive, and ER-positive BC. Treatment specialization for patients diagnosed with ILC is just in its beginnings. Accordingly, ILC deserves greater attention as a special tumor entity in BC diagnostics, patient care, and cancer research.

The oncogenic role of the cerebral endothelial cell adhesion molecule (CERCAM) in bladder cancer cells in vitro and in vivo

Bladder cancer is a menace to global health worldwide due to its high recurrence rate and its progression to invasive muscular complications. Cell adhesion molecules play an intricate role in cancer migration, growth, and invasion. Therefore, through bioinformatics analysis, it was found that the higher cerebral endothelial cell adhesion molecule (CERCAM) predicted lower chance in bladder cancer patient survival; subsequently, in vitro and in vivo investigations were performed to evaluate the specific effects of CERCAM on bladder cancer cell phenotypes and tumor growth in mice model. The PCR‐based analysis revealed an aberrant upregulation of CERCAM in bladder carcinoma tissues and cells when compared with normal controls. In vitro, functional experiments such as MTT, EdU, and Transwell assays showed that CERCAM overexpression markedly enhanced bladder cancer cell viability, DNA synthesis, and cell invasion. In contrast, CERCAM silencing suppressed bladder cancer cell viability, DNA synthesis, and cell invasion. CERCAM overexpression significantly increased PCNA, Vimentin, Twist, and N‐cadherin proteins but decreased E‐cadherin and cleaved‐caspase3, whereas CERCAM silencing exerted opposite effects on these markers. In vivo, subcutaneous implant model experiments in nude mice showed that CERCAM silencing suppressed the growth of subcutaneously implanted tumors. CERCAM altered the phosphorylation process of AKT. The PI3K inhibitor LY294002 treatment manifested similar effects as CERCAM silencing on bladder cancer cell behaviors and partially impaired the promotive functions of CERCAM overexpression upon the capacity of bladder cancer cells to proliferate and invade. When taken together, the cell adhesion molecule CERCAM is overexpressed in bladder cancer tissues. In vitro, CERCAM overexpression significantly promoted bladder cancer cell viability, DNA synthesis, and cell invasion and alters the cleaved‐caspase3, E‐cadherin, and N‐cadherin expression pattern; in vivo, CERCAM silencing suppressed tumor growth in nude mice. The PI3K/AKT signaling is suspected of interfering participate in the functions of CERCAM in bladder carcinoma.

Cadherins in early neural development

During early neural development, changes in signalling inform the expression of transcription factors that in turn instruct changes in cell identity. At the same time, switches in adhesion molecule expression result in cellular rearrangements that define the morphology of the emerging neural tube. It is becoming increasingly clear that these two processes influence each other; adhesion molecules do not simply operate downstream of or in parallel with changes in cell identity but rather actively feed into cell fate decisions. Why are differentiation and adhesion so tightly linked? It is now over 60 years since Conrad Waddington noted the remarkable "Constancy of the Wild Type" (Waddington in Nature 183: 1654-1655, 1959) yet we still do not fully understand the mechanisms that make development so reproducible. Conversely, we do not understand why directed differentiation of cells in a dish is sometimes unpredictable and difficult to control. It has long been suggested that cells make decisions as 'local cooperatives' rather than as individuals (Gurdon in Nature 336: 772-774, 1988; Lander in Cell 144: 955-969, 2011). Given that the cadherin family of adhesion molecules can simultaneously influence morphogenesis and signalling, it is tempting to speculate that they may help coordinate cell fate decisions between neighbouring cells in the embryo to ensure fidelity of patterning, and that the uncoupling of these processes in a culture dish might underlie some of the problems with controlling cell fate decisions ex-vivo. Here we review the expression and function of cadherins during early neural development and discuss how and why they might modulate signalling and differentiation as neural tissues are formed.

Differential Spatiotemporal Expression of Type I and Type II Cadherins Associated With the Segmentation of the Central Nervous System and Formation of Brain Nuclei in the Developing Mouse

Type I and type II classical cadherins comprise a family of cell adhesion molecules that regulate cell sorting and tissue separation by forming specific homo and heterophilic bonds. Factors that affect cadherin-mediated cell-cell adhesion include cadherin binding affinity and expression level. This study examines the expression pattern of type I cadherins (Cdh1, Cdh2, Cdh3, and Cdh4), type II cadherins (Cdh6, Cdh7, Cdh8, Cdh9, Cdh10, Cdh11, Cdh12, Cdh18, Cdh20, and Cdh24), and the atypical cadherin 13 (Cdh13) during distinct morphogenetic events in the developing mouse central nervous system from embryonic day 11.5 to postnatal day 56. Cadherin mRNA expression levels obtained from in situ hybridization experiments carried out at the Allen Institute for Brain Science (https://alleninstitute.org/) were retrieved from the Allen Developing Mouse Brain Atlas. Cdh2 is the most abundantly expressed type I cadherin throughout development, while Cdh1, Cdh3, and Cdh4 are expressed at low levels. Type II cadherins show a dynamic pattern of expression that varies between neuroanatomical structures and developmental ages. Atypical Cdh13 expression pattern correlates with Cdh2 in abundancy and localization. Analyses of cadherin-mediated relative adhesion estimated from their expression level and binding affinity show substantial differences in adhesive properties between regions of the neural tube associated with the segmentation along the anterior–posterior axis. Differences in relative adhesion were also observed between brain nuclei in the developing subpallium (basal ganglia), suggesting that differential cell adhesion contributes to the segregation of neuronal pools. In the adult cerebral cortex, type II cadherins Cdh6, Cdh8, Cdh10, and Cdh12 are abundant in intermediate layers, while Cdh11 shows a gradated expression from the deeper layer 6 to the superficial layer 1, and Cdh9, Cdh18, and Cdh24 are more abundant in the deeper layers. Person’s correlation analyses of cadherins mRNA expression patterns between areas and layers of the cerebral cortex and the nuclei of the subpallium show significant correlations between certain cortical areas and the basal ganglia. The study shows that differential cadherin expression and cadherin-mediated adhesion are associated with a wide range of morphogenetic events in the developing central nervous system including the organization of neurons into layers, the segregation of neurons into nuclei, and the formation of neuronal circuits.

Role of FAT1 in health and disease

FAT atypical cadherin 1 (FAT1), which encodes a protocadherin, is one of the most frequently mutated genes in human cancer. Over the past 20 years, the role of FAT1 in tissue growth and in the development of diseases has been extensively studied. There is definitive evidence that FAT1 serves a substantial role in the maintenance of organs and development, and its expression appears to be tissue-specific. FAT1 activates a variety of signaling pathways through protein-protein interactions, including the Wnt/β-catenin, Hippo and MAPK/ERK signaling pathways, which affect cell proliferation, migration and invasion. Abnormal FAT1 expression may lead to the development of tumors and may affect prognosis. Therefore, FAT1 may have potential in tumor therapy. The structural and functional changes mediated by FAT1, its tissue distribution and changes in FAT1 expression in human diseases are described in the present review, which provides further insight for understanding the role of FAT1 in development and disease.

Changes in Transcriptome and Gene Expression in Sogatella furcifera (Hemiptera: Delphacidae) in Response to Cycloxaprid

The white-backed planthopper, Sogatella furcifera (Horváth), causes substantial damage to crops by direct feeding or virus transmission, especially southern rice black-streaked dwarf virus, which poses a serious threat to rice production. Cycloxaprid, a novel cis-nitromethylene neonicotinoid insecticide, has high efficacy against rice planthoppers, including imidacloprid-resistant populations. However, information about the influence of cycloxaprid on S. furcifera (Hemiptera: Delphacidae) at the molecular level is limited. Here, by de novo transcriptome sequencing and assembly, we constructed two transcriptomes of S. furcifera and profiled the changes in gene expression in response to cycloxaprid at the transcription level. We identified 157,906,456 nucleotides and 131,601 unigenes using the Illumina technology from cycloxaprid-treated and untreated S. furcifera. In total, 38,534 unigenes matched known proteins in at least one database, accounting for 29.28% of the total unigenes. The number of coding DNA sequences was 28,546 and that of amino acid sequences in the coding region was 22,299. In total, 15,868 simple sequence repeats (SSRs) were identified. The trinucleotide repeats accounted for 45.1% (7,157) of the total SSRs and (AAG/CTT)n were the most frequent motif. There were 359 differentially expressed genes that might have been induced by cycloxaprid. There were 131 upregulated and 228 downregulated genes. Twenty-two unigenes might be involved in resistance against cycloxaprid, such as cytochrome P450, glutathione S-transferase (GST), acid phosphatase (ACP), and cadherin. Our study provides vital information on cycloxaprid-induced resistance mechanisms, which will be useful to analyze the molecular mechanisms of cycloxaprid resistance and may lead to the development of novel strategies to manage S. furcifera.