Identification of the human PMR1 mRNA endonuclease as an alternatively processed product of the gene for peroxidasin-like protein

DNA Methylation of PXDN Is Associated with Early-Life Adversity in Adult Mental Disorders

Early-life adversity (ELA) is characterized by exposure to traumatic events during early periods of life, particularly involving emotional, sexual and/or physical adversities during childhood. Mental disorders are strongly influenced by environmental and lifestyle-related risk factors including ELA. However, the molecular link between ELA and the risk of an adult mental disorder is still not fully understood. Evidence is emerging that long-lasting changes in the epigenetic processes regulating gene expression, such as DNA methylation, play an important role in the biological mechanisms linking ELA and mental disorders. Based on a recent study, we analyzed the DNA methylation of a specific CpG site within the gene PXDN-cg10888111-in blood in the context of ELA across a set of psychiatric disorders, namely Borderline Personality Disorder (BPD), Major Depressive Disorder (MDD) and Social Anxiety Disorder (SAD), and its potential contribution to their pathogenesis. We found significant hypermethylation in mentally ill patients with high levels of ELA compared to patients with low levels of ELA, whereas cg10888111 methylation in healthy control individuals was not affected by ELA. Further investigations revealed that this effect was driven by the MDD cohort. Providing a direct comparison of cg10888111 DNA methylation in blood in the context of ELA across three mental disorders, our results indicate the role of PXDN regulation in the response to ELA in the pathogenesis of mental disorders, especially MDD. Further studies will be needed to validate these results and decipher the corresponding biological network that is involved in the transmission of ELA to an adult mental disorder in general.

PXDNL activates the motility of urothelial bladder carcinoma cells through the Wnt/β-catenin pathway and has a prognostic value

AIMS

Although aberrant expression of peroxidasin-like (PXDNL) has been associated with carcinogenesis, its potential role in the Urothelial Carcinoma of the Bladder (UCB) remains unknown. The present study aimed to explore the role of PXDNL in UCB carcinogenesis and its potential clinical value.

MAIN METHODS

Based on The Cancer Genome Atlas (TCGA) data, bioinformatics was used to explore the potential clinical value of PXDNL. Wound healing and Transwell invasion assays were employed for the purpose of assessing the cell motility, while the Western Blotting experiments were utilized for investigating the protein expression pattern of PXDNL in UCB and investigating the Epithelial-to-Mesenchymal Transition (EMT) and Wnt/β-catenin pathways for understanding the probable mechanisms involved.

KEY FINDS

PXDNL mRNA was overexpressed in UCB tissues and indicated a poor prognosis. High PXDNL mRNA levels were also associated with advanced clinicopathological features and were regarded as independent prognostic factors for UCB. However, PXDNL showed a weak correlation with immune cell infiltration in UCB. In addition, the findings of the study verified that the existing form of the PXDNL protein was 57-kDa and it was upregulated in the UCB cell lines and tissue samples. Furthermore, silencing PXDNL inhibited, while overexpressing PXDNL promoted EMT and motility of UCB cells in vitro. Mechanistic studies showed that PXDNL activated UCB cell motility via the Wnt/β-catenin pathway.

SIGNIFICANCE

The results reveal a novel molecular target that could be further explored for developing preventive, predictive, and individualized treatment strategies for UCB.

High peroxidasin-like expression is a potential and independent prognostic biomarker in breast cancer

Breast cancer is a frequent female malignant tumor with high mortality and poor prognosis. Peroxidasin like (PXDNL) has many biological functions, including characteristic activity of hormone biosynthesis, host defense, and cell motility. In addition, PXDNL is closely connected with the progression of breast cancer. In this study, we found that PXDNL may be an independent prognostic biomarker of breast cancer.We tested the mRNA expression of PXDNL in breast cancer by detecting The Cancer Genome Atlas (TCGA) database. The chi-squared test was used to evaluate clinical correlation. The receiver operating characteristic (ROC) curves were drawn to evaluate diagnosis potential in breast cancer. Subsequently, survival analyses were performed to identify the relevance between the expression of PXDNL and the overall survival/relapse-free survival of patients with breast cancer. Univariate/multivariate Cox regression model was executed to detect risk factors affecting the prognosis of patients with breast cancer.PXDNL is highly expressed in breast cancer tissues and is related to survival status of patients. The ROC curve showed that PXDNL had beneficial diagnostic ability in breast cancer. Survival analysis indicated that patients with breast cancer with high PXDNL expression generally had decreased overall survival/relapse-free survival. Univariate/multivariate Cox model analyses further suggested an association between PXDNL expression and prognosis of patients with breast cancer.High PXDNL expression is a potential and independent prognostic biomarker in breast cancer.

The human PMR1 endonuclease stimulates cell motility by down regulating miR-200 family microRNAs

The motility of MCF-7 cells increases following expression of a human PMR1 transgene and the current study sought to identify the molecular basis for this phenotypic change. Ensemble and single cell analyses show increased motility is dependent on the endonuclease activity of hPMR1, and cells expressing active but not inactive hPMR1 invade extracellular matrix. Nanostring profiling identified 14 microRNAs that are downregulated by hPMR1, including all five members of the miR-200 family and others that also regulate invasive growth. miR-200 levels increase following hPMR1 knockdown, and changes in miR-200 family microRNAs were matched by corresponding changes in miR-200 targets and reporter expression. PMR1 preferentially cleaves between UG dinucleotides within a consensus YUGR element when present in the unpaired loop of a stem–loop structure. This motif is present in the apical loop of precursors to most of the downregulated microRNAs, and hPMR1 targeting of pre-miRs was confirmed by their loss following induced expression and increase following hPMR1 knockdown. Introduction of miR-200c into hPMR1-expressing cells reduced motility and miR-200 target gene expression, confirming hPMR1 acts upstream of Dicer processing. These findings identify a new role for hPMR1 in the post-transcriptional regulation of microRNAs in breast cancer cells.

Pathophysiological aspects of thyroid hormone disorders/thyroid peroxidase autoantibodies and reproduction

BACKGROUND

Thyroid hormone disorders and thyroid peroxidase autoantibodies (TPO-Ab) in women are associated with subfertility and early pregnancy loss. Here, we aim to provide a comprehensive overview of the literature on the pathophysiology of these associations.

METHODS

A review of the literature in the English language was carried out. Relevant studies were identified by searching Medline, EMBASE and the Cochrane Controlled Trials Register from 1975 until March 2014.

RESULTS

From a total of 6108 primary selected articles from the literature search, 105 articles were selected for critical appraisal. Observational data indicate that altered thyroid hormone levels are associated with disturbed folliculogenesis, spermatogenesis, lower fertilization rates and lower embryo quality. Triiodothyronine (T3) in combination with FSH enhances granulosa cell proliferation and inhibits granulosa cell apoptosis by the PI3K/Akt pathway. T3 is considered a biological amplifier of the stimulatory action of gonadotrophins on granulosa cell function. T3 increases the expression of matrix metalloproteinases (MMP), MMP-2, MMP-3, fetal fibronectin and integrin α5β1T3 in early placental extravillous trophoblasts. Thyroid hormone transporters and receptors are expressed in the ovary, early embryo, endometrium, uterus and placenta. No other data explaining the associations could be retrieved from the literature. The presence of TPO-Ab is negatively associated with spermatogenesis, fertilization and embryo quality, but no data are available on the potential pathophysiological mechanisms.

CONCLUSIONS

Thyroid hormone disorders and TPO-Ab are associated with disturbed folliculogenesis, spermatogenesis, fertilization and embryogenesis. The pathophysiology of these associations remains largely unknown, as evidence is limited and includes studies using small sample sizes, and often restricted to animal models. There are no studies on the pathophysiology underlying the association between TPO-Ab and reproduction. The available evidence, although limited, supports a role of thyroid hormone in fertility and early pregnancy. This justifies clinical intervention studies on the effects of thyroid hormone supplementation in women with subclinical hypothyroidism and in women prone to develop hypothyroidism due to the presence of TPO-Ab. In addition, more research is needed to identify the underlying mechanisms. This would be of particular interest in women undergoing IVF to pinpoint the effects of thyroid hormone on different parameters of reproduction.

Peroxidasin-like protein: a novel peroxidase homologue in the human heart

AIMS

Peroxidases serve diverse biological functions including well-characterized activities in host defence and hormone biosynthesis. More recently, peroxidasin (PXDN) was found to be involved in collagen IV cross-linking in the extracellular matrix (ECM). The aim of this study was to characterize the expression and function of peroxidasin-like protein (PXDNL), a previously unknown peroxidase homologue.

METHODS AND RESULTS

We cloned the PXDNL cDNA from the human heart and identified its expression pattern by northern blot, in situ hybridization, and immunohistochemistry. PXDNL is expressed exclusively in the heart and it has evolved to lose its peroxidase activity. The protein is produced by cardiomyocytes and localizes to cell-cell junctions. We also demonstrate that PXDNL can form a complex with PXDN and antagonizes its peroxidase activity. Furthermore, we show an increased expression of PXDNL in the failing myocardium.

CONCLUSION

PXDNL is a unique component of the heart with a recently evolved inactivation of peroxidase function. The elevation of PXDNL levels in the failing heart may contribute to ECM dysregulation due to its antagonism of PXDN function.

Peroxidasin: tying the collagen-sulfilimine knot

Type IV collagen, a major constituent of basement membranes, contains an unusual intermolecular sulfilimine crosslink whose route of biosynthesis has remained undefined. An oxidative triad consisting of peroxidasin, H(2)O(2) and halide is now shown to drive sulfilimine generation in vivo.