Zebrafish calsyntenins mediate homophilic adhesion through their amino-terminal cadherin repeats

Axonal transport of Frizzled5 by Alcadein α-containing vesicles is associated with kinesin-1

Alcadein α (Alcα) and amyloid-β protein precursor (APP) are cargo receptors that associate vesicles with kinesin-1. These vesicles, which contain either Alcα or APP, transport various proteins/cargo molecules into axon nerve terminals. Here, we analyzed immune-isolated Alcα- and APP-containing vesicles of adult mouse brains with LC-MS/MS and identified proteins present in vesicles that contained either Alcα or APP. Among these proteins, Frizzled-5 (Fzd5), a Wnt receptor, was detected mainly in Alcα vesicles. Although colocalization ratios of Fzd5 with Alcα are low in the neurites of differentiating neurons by a low expression of Fzd5 in embryonic brains, the suppression of Alcα expression decreased the localization of Fzd5 in neurites of primary cultured neurons. Furthermore, Fzd5-EGFP expressed in primary cultured neurons was preferentially transported in axons with the transport velocities of Alcα vesicles. In synaptosomal fractions of adult-mice brains that express higher levels of Fzd5, the amount of Fzd5 and the phosphorylation level of calcium/calmodulin-dependent protein kinase-II were reduced in the Alcα-deficient mice. These results suggest that reduced transport of Fzd5 by Alcα-containing vesicles associated with kinesin-1 in axon terminals may impair the response to Wnt ligands in the noncanonical Ca2+-dependent signal transduction pathway at nerve terminals of mature neurons.

Genome-wide association analyses identify 39 new susceptibility loci for diverticular disease

Diverticular disease is common and has a high morbidity. Treatments are limited owing to the poor understanding of its pathophysiology. Here, to elucidate its etiology, we performed a genome-wide association study of diverticular disease (27,444 cases; 382,284 controls) from the UK Biobank and tested for replication in the Michigan Genomics Initiative (2,572 cases; 28,649 controls). We identified 42 loci associated with diverticular disease; 39 of these loci are novel. Using data-driven expression-prioritized integration for complex traits (DEPICT), we show that genes in these associated regions are significantly enriched for expression in mesenchymal stem cells and multiple connective tissue cell types and are co-expressed with genes that have a role in vascular and mesenchymal biology. Genes in these associated loci have roles in immunity, extracellular matrix biology, cell adhesion, membrane transport and intestinal motility. Phenome-wide association analysis of the 42 variants shows a common etiology of diverticular disease with obesity and hernia. These analyses shed light on the genomic landscape of diverticular disease.

The C-terminal of CASY-1/Calsyntenin regulates GABAergic synaptic transmission at the Caenorhabditis elegans neuromuscular junction

The C. elegans ortholog of mammalian calsyntenins, CASY-1, is an evolutionarily conserved type-I transmembrane protein that is highly enriched in the nervous system. Mammalian calsyntenins are strongly expressed at inhibitory synapses, but their role in synapse development and function is still elusive. Here, we report a crucial role for CASY-1 in regulating GABAergic synaptic transmission at the C. elegans neuromuscular junction (NMJ). The shorter isoforms of CASY-1; CASY-1B and CASY-1C, express and function in GABA motor neurons where they regulate GABA neurotransmission. Using pharmacological, behavioral, electrophysiological, optogenetic and imaging approaches we establish that GABA release is compromised at the NMJ in casy-1 mutants. Further, we demonstrate that CASY-1 is required to modulate the transport of GABAergic synaptic vesicle (SV) precursors through a possible interaction with the SV motor protein, UNC-104/KIF1A. This study proposes a possible evolutionarily conserved model for the regulation of GABA synaptic functioning by calsyntenins.

GABA acts as a major inhibitory neurotransmitter in both vertebrate and invertebrate nervous systems. Despite the potential deregulation of GABA signaling in several neurological disorders, our understanding of the genetic factors that regulate GABAergic synaptic transmission has just started to evolve. Here, we identify a role for a cell adhesion molecule, CASY-1, in regulating GABA signaling at the C. elegans NMJ. We show that the mutants in casy-1 have reduced number of GABA vesicles at the synapse resulting in less GABA release from the presynaptic GABAergic motor neurons. Further, we show that the shorter isoforms of the casy-1 gene; casy-1b and casy-1c that carry a potential kinesin-motor binding domain are responsible for maintaining GABAergic signaling at the synapse. We show a novel interaction of the CASY-1 isoforms with the C- terminal of the UNC-104/KIF1A motor protein that mediates the trafficking of GABAergic synaptic vesicle precursors to the synapse, thus maintaining normal inhibitory signaling at the NMJ.

Paired Expression Analysis of Tumor Cell Surface Antigens

Adoptive immunotherapy with antibody-based therapy or with T cells transduced to express chimeric antigen receptors (CARs) is useful to the extent that the cell surface membrane protein being targeted is not expressed on normal tissues. The most successful CAR-based (anti-CD19) or antibody-based therapy (anti-CD20) in hematologic malignancies has the side effect of eliminating the normal B cell compartment. Targeting solid tumors may not provide a similar expendable marker. Beyond antibody to Her2/NEU and EGFR, very few antibody-based and no CAR-based therapies have seen broad clinical application for solid tumors. To expand the way in which the surfaceome of solid tumors can be analyzed, we created an algorithm that defines the pairwise relative overexpression of surface antigens. This enables the development of specific immunotherapies that require the expression of two discrete antigens on the surface of the tumor target. This dyad analysis was facilitated by employing the Hotelling’s T-squared test (Hotelling–Lawley multivariate analysis of variance) for two independent variables in comparison to a third constant entity (i.e., gene expression levels in normal tissues). We also present a unique consensus scoring mechanism for identifying transcripts that encode cell surface proteins. The unique application of our bioinformatics processing pipeline and statistical tools allowed us to compare the expression of two membrane protein targets as a pair, and to propose a new strategy based on implementing immunotherapies that require both antigens to be expressed on the tumor cell surface to trigger therapeutic effector mechanisms. Specifically, we found that, for MYCN amplified neuroblastoma, pairwise expression of ACVR2B or anaplastic lymphoma kinase (ALK) with GFRA3, GFRA2, Cadherin 24, or with one another provided the strongest hits. For MYCN, non-amplified stage 4 neuroblastoma, neurotrophic tyrosine kinase 1, or ALK paired with GFRA2, GFRA3, SSK1, GPR173, or with one another provided the most promising paired-hits. We propose that targeting these markers together would increase the specificity and thereby the safety of CAR-based therapy for neuroblastoma.

Evolution and diversity of cadherins and catenins

Cadherin genes encode a superfamily of conserved transmembrane proteins that share an adhesive ectodomain composed of tandem cadherin repeats. More than 100 human cadherin superfamily members have been identified, which can be classified into three families: major cadherins, protocadherins and cadherin-related proteins. These superfamily members are involved in diverse fundamental cellular processes including cell-cell adhesion, morphogenesis, cell recognition and signaling. Epithelial cadherin (E-cadherin) is the founding cadherin family member. Its cytoplasmic tail interacts with the armadillo catenins, p120 and β-catenin. Further, α-catenin links the cadherin/armadillo catenin complex to the actin filament network. Even genomes of ancestral metazoan species such as cnidarians and placozoans encode a limited number of distinct cadherins and catenins, emphasizing the conservation and functional importance of these gene families. Moreover, a large expansion of the cadherin and catenin families coincides with the emergence of vertebrates and reflects a major functional diversification in higher metazoans. Here, we revisit and review the functions, phylogenetic classifications and co-evolution of the cadherin and catenin protein families.

Genome-Wide Association Study for Identifying Loci that Affect Fillet Yield, Carcass, and Body Weight Traits in Rainbow Trout (Oncorhynchus mykiss)

Fillet yield (FY, %) is an economically-important trait in rainbow trout aquaculture that affects production efficiency. Despite that, FY has received little attention in breeding programs because it is difficult to measure on a large number of fish and cannot be directly measured on breeding candidates. The recent development of a high-density SNP array for rainbow trout has provided the needed tool for studying the underlying genetic architecture of this trait. A genome-wide association study (GWAS) was conducted for FY, body weight at 10 (BW10) and 13 (BW13) months post-hatching, head-off carcass weight (CAR), and fillet weight (FW) in a pedigreed rainbow trout population selectively bred for improved growth performance. The GWAS analysis was performed using the weighted single-step GBLUP method (wssGWAS). Phenotypic records of 1447 fish (1.5 kg at harvest) from 299 full-sib families in three successive generations, of which 875 fish from 196 full-sib families were genotyped, were used in the GWAS analysis. A total of 38,107 polymorphic SNPs were analyzed in a univariate model with hatch year and harvest group as fixed effects, harvest weight as a continuous covariate, and animal and common environment as random effects. A new linkage map was developed to create windows of 20 adjacent SNPs for use in the GWAS. The two windows with largest effect for FY and FW were located on chromosome Omy9 and explained only 1.0-1.5% of genetic variance, thus suggesting a polygenic architecture affected by multiple loci with small effects in this population. One window on Omy5 explained 1.4 and 1.0% of the genetic variance for BW10 and BW13, respectively. Three windows located on Omy27, Omy17, and Omy9 (same window detected for FY) explained 1.7, 1.7, and 1.0%, respectively, of genetic variance for CAR. Among the detected 100 SNPs, 55% were located directly in genes (intron and exons). Nucleotide sequences of intragenic SNPs were blasted to the Mus musculus genome to create a putative gene network. The network suggests that differences in the ability to maintain a proliferative and renewable population of myogenic precursor cells may affect variation in growth and fillet yield in rainbow trout.

Effects of β-diketone antibiotic mixtures on behavior of zebrafish (Danio rerio)

To date, few data are available on neurotoxicity of β-diketone antibiotics (DKAs) from the perspective of animal behavior. Herein, the effects of long-term DKAs exposure on zebrafish (Danio rerio) behavior were assessed for locomotor activity, anxiety, social interaction and their related molecular mechanisms. DKAs exposure to zebrafish consisted of six DKA species, including ofloxacin, ciprofloxacin, enrofloxacin, doxycycline, chlortetracycline and oxytetracycline, with equal weight concentration and equal volume. DKAs at 6.25 mg/L significantly increased the time spent in the upper portion of the test tank (+40%) and the number of line crossings (±42%), indicating occurrence of anxiolytic behavior. For conditioned place preference test, long-term DKAs exposure at 6.25 mg/L increased the number of motionless positions in the non-preferred white side (+31%), number of transitions to the white side (+221%) and time spent in the white side (+35%) in relation to the control. DKAs at 6.25 mg/L significantly increased zebrafish shoaling behavior (+38%) resulting from an anxiety-like state, but 25 mg/L DKAs exposure decreased zebrafish social cohesion (-41%) possibly due to an autism-like state. With increasing DKAs-exposure concentration, the signal intensity of (1)O2 gradually decreased, leading to insufficient energy supply and movement functional disorders. Based on GO functional annotation and metabolic pathway analysis, 11 genes closely associated with locomotor behavior were identified. Using qRT-PCR, we confirmed that DKAs exposure led to changes in the transcriptional levels of 11 locomotor-related genes. These results suggest that behavior is a potential strategy for evaluating mechanisms underlying the neurochemical basis triggered by stress in zebrafish.