Bone morphogenetic protein/retinoic acid inducible neural-specific protein (brinp) expression during Danio rerio development

Molecular evolution of the BRINP and ASTN genes and expression profles in response to pathogens and spinal cord injury repair in lamprey (Lethenteron reissneri)

Bone morphogenic protein/retinoic acid inducible neural-specific proteins (BRINPs) and astrotactins (ASTNs) are two members of membrane attack complex/perforin-like (MACPF) superfamily proteins that present high expression in the growing and mature vertebrate neurons. Lamprey has a unique evolutionary status as a representative of the oldest jawless vertebrates, making it an ideal animal model for understanding vertebrate evolution. The evolutionary origins of BRINPs and ASTNs genes in vertebrates, however, have not been shown in lampreys. Here, BRINP and ASTN genes were found in lamprey genomes and the evolutionary relationships of them were investigated by phylogenetic analysis. Protein domains, motifs, genetic structure, and crystal structure analysis revealed that the features of BRINP and ASTN appear to be conserved in vertebrates. Genomic synteny analysis indicated that lamprey BRINP and ASTN neighbor genes differed dramatically from jawed vertebrate. Real-time quantitative results illustrated that the BRINP and ASTN genes family might take part in immune defence and spinal cord injury repair. This study not only enriches a better understanding of the evolution of the BRINP and ASTN genes but also offers a foundation for exploring their roles in the development of the vertebrate central nervous system (CNS).

Overexpression of BRINP3 Predicts Poor Prognosis and Promotes Cancer Cell Proliferation and Migration via MAP4 in Osteosarcoma

Osteosarcoma (OS) is a primary malignant bone tumor most commonly affecting children and adolescents and is characterized by loss of differentiation. Bone morphogenetic protein/retinoic acid inducible neural-specific 3 (BRINP3) has been reported to regulate the differentiation of osteoblasts. However, the role that BRINP3 plays in the progression of osteosarcoma remains unknown. We found in this study that BRINP3 was highly expressed in 64.13% of human osteosarcoma tissues and it was associated with histological grade, tumor recurrence, and poor clinical prognosis of osteosarcoma. In vitro, downregulation of BRINP3 was able to inhibit the proliferation and invasion of osteosarcoma cell lines. Furthermore, BRINP3 interacted with microtubule-associated protein 4 (MAP4) at the protein level, and overexpression of MAP4 could partially reverse the inhibitory effect of downregulated BRINP3 on the proliferation and invasion of osteosarcoma cells, which indicates that downregulation of BRINP3 might suppress the proliferation and invasion of osteosarcoma cells by inhibiting MAP4 expression. Overall, our results demonstrate that BRINP3 functions as an oncogene within osteosarcoma through MAP4 and could therefore be used as a potential biomarker for osteosarcoma diagnostics and therapeutics.

Integrative analysis of lncRNAs, miRNAs, and mRNAs-associated ceRNA network in a neonatal mouse model of bronchopulmonary dysplasia

OBJECTIVE

To elucidate the potential roles of the lncRNA-mediated competitive endogenous RNA (ceRNA) network in the pathogenesis of bronchopulmonary dysplasia (BPD), we performed an integrated bioinformatics analysis based on miRNA and mRNA microarray datasets between BPD and normal samples.

STUDY DESIGN

The mRNA and miRNA expression profiles of BPD were downloaded from the Gene Expression Omnibus (GEO) database to perform an integrated analysis. The limma package was used to identify differentially expressed genes (DEGs) and differentially expressed miRNA (DEmiRs), followed by functional enrichment analysis of DEGs. DEmiR-DEG and DEmiRNA-lncRNA interactions were predicted. Subsequently, the lncRNA-related ceRNA network was structured. Finally, a newborn BPD mouse model was established, and quantitative real-time PCR (qPCR) was used to validate the expression of the selected mRNAs, miRNAs, and lncRNAs.

RESULTS

A total of 445 DEGs and 155 DEmiRs were obtained by comparing BPD samples and normal samples. Functional enrichment analysis showed that DEGs were primarily enriched in GO terms such as cell division and inflammatory response; and DEGs were mainly involved in the p53 signaling pathway. The miR17hg-miR-130b-3p-roundabout guidance receptor 2 (Robo2) and GM20455-miR-34a-5p-BMP/retinoic acid-inducible neural specific 1 (Brinp1) ceRNA axes were obtained by constructing the ceRNA network. In addition, the upregulation of Robo2 and miR17hg while the downregulation of miR-130b-3p; as well as the upregulation of Brinp1 and GM20455 but the downregulation of miR-34a-5p were validated by qPCR.

CONCLUSION

The miR17hg-miR-130b-3p-Robo2 and GM20455-miR-34a-5p-Brinp1 axes may serve important role in the development of BPD. These findings might provide novel insight for a comprehensive understanding of molecular mechanisms in BPD, and genes in the ceRNA network might be considered as potential biomarkers and therapeutic targets against BPD.

Parental exposure to environmental concentrations of tris(1,3-dichloro-2-propyl)phosphate induces abnormal DNA methylation and behavioral changes in F1 zebrafish larvae

Tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) has been demonstrated to be transferred from parental animals to their offspring. However, whether parental exposure to environmental concentrations of TDCIPP show neurodevelopmental toxicity in the F1 generation and the possible underlying mechanism remain unclear. Therefore, in this study, zebrafish embryos were exposed to environmental concentrations of TDCIPP (3, 30 and 300 ng L^-1) for 120 days. The effects of exposure on motor behaviors, neurotransmitter levels, DNA methylation, and gene expression of F1 larvae were investigated. Parental exposure left TDCIPP residues in F1 eggs as well as reduced body length of F1 larvae. Moreover, parental exposure significantly reduced swimming activity in F1 5 dpf larvae, although it did not significantly alter serotonin, dopamine, 3,4-dihydroxyphenylacetic acid, γ-aminobutyrate, and acetylcholine levels. Genes encoding DNA methylation transferases (dnmt3aa and dnmt1) were downregulated in F1 larvae. Reduced representation bisulfite sequencing analysis revealed 446 differentially methylated regions and enriched neuronal cell body Gene Ontology term in F1 generation. Correlation analysis between the expression of genes related to neural cell body and swimming speed indicated that solute carrier family 1 member 2b (slc1a2b) downregulation might be responsible for the inhibition of motor behaviors. Furthermore, bisulfite amplicon sequencing analysis confirmed hypermethylation of the promoter region of slc1a2b in F1 larvae following parental exposure to 300 ng L^-1 TDCIPP, which might have led to significant downregulation of gene expression and, in turn, influenced the motor behaviors. These results indicate that parental exposure to environmental concentrations of TDCIPP alters DNA methylation, downregulates gene expressions and, thus inducing developmental neurotoxicity, in F1 larvae.

Functional characterization and gene expression profile of perforin-2 in starry flounder (Platichthys stellatus)

The membrane attack complex/perforin (MACPF) superfamily consists of multifunctional proteins that form pores on the membrane surface of microorganisms to induce their death and have various immune-related functions. PFN2 is a perforin-like protein with an MACPF domain, and humans with deficient PFN2 levels have increased susceptibility to bacterial infection, which can lead to fatal consequences for some patients. Therefore, in this study, we confirmed the antimicrobial function of PFN2 in starry flounder (Platichthys stellatus). The molecular properties were confirmed based on the verified amino acid sequence of PsPFN2. In addition, the expression characteristics of tissue-specific and pathogen-specific PsPFN2 mRNA were also confirmed. The recombinant protein was produced using Escherichia coli, and the antimicrobial activity was then confirmed. The coding sequence of PFN2 (PsPFN2) in P. stellatus consists of 710 residues. The MACPF domain was conserved throughout evolution, as shown by multiple sequence alignment and phylogenetic analysis. PsPFN2 mRNA is abundantly distributed in immune-related organs such as the spleen and gills of healthy starry flounder, and significant expression changes were confirmed after artificial infection by bacteria or viruses. We cloned the MACPF domain region of PFN2 to produce a recombinant protein (rPFN2) and confirmed its antibacterial effect against a wide range of bacterial species and the parasite (Miamiensis avidus).

Repurposing a pore: highly conserved perforin-like proteins with alternative mechanisms

Pore-forming proteins play critical roles in pathogenic attack and immunological defence. The membrane attack complex/perforin (MACPF) group of homologues represents, with cholesterol-dependent cytolysins, the largest family of such proteins. In this review, we begin by describing briefly the structure of MACPF proteins, outlining their common mechanism of pore formation. We subsequently discuss some examples of MACPF proteins likely implicated in pore formation or other membrane-remodelling processes. Finally, we focus on astrotactin and bone morphogenetic protein and retinoic acid-induced neural-specific proteins, highly conserved MACPF family members involved in developmental processes, which have not been well studied to date or observed to form a pore-and which data suggest may act by alternative mechanisms.This article is part of the themed issue 'Membrane pores: from structure and assembly, to medicine and technology'.

Neurodevelopmental MACPFs: The vertebrate astrotactins and BRINPs

Astrotactins (ASTNs) and Bone morphogenetic protein/retinoic acid inducible neural-specific proteins (BRINPs) are two groups of Membrane Attack Complex/Perforin (MACPF) superfamily proteins that show overlapping expression in the developing and mature vertebrate nervous system. ASTN(1-2) and BRINP(1-3) genes are found at conserved loci in humans that have been implicated in neurodevelopmental disorders (NDDs). Here we review the tissue distribution and cellular localization of these proteins, and discuss recent studies that provide insight into their structure and interactions. We highlight the genetic relationships and co-expression of Brinps and Astns; and review recent knock-out mouse phenotypes that indicate a possible overlap in protein function between ASTNs and BRINPs.

Mice Lacking Brinp2 or Brinp3, or Both, Exhibit Behaviors Consistent with Neurodevelopmental Disorders

Background:Brinps 1–3, and Astrotactins (Astn) 1 and 2, are members of the Membrane Attack Complex/Perforin (MACPF) superfamily that are predominantly expressed in the mammalian brain during development. Genetic variation at the human BRINP2/ASTN1 and BRINP1/ASTN2 loci has been implicated in neurodevelopmental disorders. We, and others, have previously shown that Brinp1^−/− mice exhibit behavior reminiscent of autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD).

Method: We created Brinp2^−/− mice and Brinp3^−/− mice via the Cre-mediated LoxP system to investigate the effect of gene deletion on anatomy and behavior. Additionally, Brinp2^−/−Brinp3^−/− double knock-out mice were generated by interbreeding Brinp2^−/− and Brinp3^−/− mice. Genomic validation was carried out for each knock-out line, followed by histological, weight and behavioral examination. Brinp1^−/−Brinp2^−/−Brinp3^−/− triple knock-out mice were also generated by crossing Brinp2/3 double knock-out mice with previously generated Brinp1^−/− mice, and examined by weight and histological analysis.

Results:Brinp2^−/− and Brinp3^−/− mice differ in their behavior: Brinp2^−/− mice are hyperactive, whereas Brinp3^−/− mice exhibit marked changes in anxiety-response on the elevated plus maze. Brinp3^−/− mice also show evidence of altered sociability. Both Brinp2^−/− and Brinp3^−/− mice have normal short-term memory, olfactory responses, pre-pulse inhibition, and motor learning. The double knock-out mice show behaviors of Brinp2^−/− and Brinp3^−/− mice, without evidence of new or exacerbated phenotypes.

Conclusion:Brinp3 is important in moderation of anxiety, with potential relevance to anxiety disorders. Brinp2 dysfunction resulting in hyperactivity may be relevant to the association of ADHD with chromosome locus 1q25.2. Brinp2^−/− and Brinp3^−/− genes do not compensate in the mammalian brain and likely have distinct molecular or cell-type specific functions.

The membrane attack complex, perforin and cholesterol-dependent cytolysin superfamily of pore-forming proteins

The membrane attack complex and perforin proteins (MACPFs) and bacterial cholesterol-dependent cytolysins (CDCs) are two branches of a large and diverse superfamily of pore-forming proteins that function in immunity and pathogenesis. During pore formation, soluble monomers assemble into large transmembrane pores through conformational transitions that involve extrusion and refolding of two α-helical regions into transmembrane β-hairpins. These transitions entail a dramatic refolding of the protein structure, and the resulting assemblies create large holes in cellular membranes, but they do not use any external source of energy. Structures of the membrane-bound assemblies are required to mechanistically understand and modulate these processes. In this Commentary, we discuss recent advances in the understanding of assembly mechanisms and molecular details of the conformational changes that occur during MACPF and CDC pore formation.