A novel missense variant in the EML1 gene associated with bilateral ribbon-like subcortical heterotopia leads to ciliary defects

Heterotopia is a brain malformation caused by a failed migration of cortical neurons during development. Clinical symptoms of heterotopia vary in severity of intellectual disability and may be associated with epileptic disorders. Abnormal neuronal migration is known to be associated with mutations in the doublecortin gene (DCX), the platelet-activating factor acetylhydrolase gene (PAFAH1B1), or tubulin alpha-1A gene (TUBA1A). Recently, a new gene encoding echinoderm microtubule-associated protein-like 1 (EML1) was reported to cause a particular form of subcortical heterotopia, the ribbon-like subcortical heterotopia (RSH). EML1 mutations are inherited in an autosomal recessive manner. Only six unrelated EML1-associated heterotopia-affected families were reported so far. The EML1 protein is a member of the microtubule-associated proteins family, playing an important role in microtubule assembly and stabilization as well as in mitotic spindle formation in interphase. Herein, we present a novel homozygous missense variant in EML1 (NM_004434.2: c.692G>A, NP_004425.2: p.Gly231Asp) identified in a male RSH-affected patient. Our clinical and molecular findings confirm the genotype-phenotype associations of EML1 mutations and RSH. Analyses of patient-derived fibroblasts showed the significantly reduced length of primary cilia. In addition, our results presented, that the mutated EML1 protein did not change binding capacities with tubulin. The data described herein will expand the mutation spectrum of the EML1 gene and provide further insight into molecular and cellular bases of the pathogenic mechanisms underlying RSH.

Platelet-Activating Factor Acetylhydrolase Expression in BRCA1 Mutant Ovarian Cancer as a Protective Factor and Potential Negative Regulator of the Wnt Signaling Pathway

Aberrantly activated Wnt/β-catenin signaling pathway, as well as platelet-activating factor (PAF), contribute to cancer progression and metastasis of many cancer entities. Nonetheless, the role of the degradation enzyme named platelet-activating factor acetylhydrolase (PLA2G7/PAF-AH) in ovarian cancer etiology is still unclear. This study investigated the functional impact of platelet-activating factor acetylhydrolase on BRCA1 mutant ovarian cancer biology and its crosstalk with the Wnt signaling pathway. PAF-AH, pGSK3β, and β-catenin expressions were analyzed in 156 ovarian cancer specimens by immunohistochemistry. PAF-AH expression was investigated in ovarian cancer tissue, serum of BRCA1-mutated patients, and in vitro in four ovarian cancer cell lines. Functional assays were performed after PLA2G7 silencing. The association of PAF-AH and β-catenin was examined by immunocytochemistry. In an established ovarian carcinoma collective, we identified PAF-AH as an independent positive prognostic factor for overall survival (median 59.9 vs. 27.4 months; p = 0.016). PAF-AH correlated strongly with the Wnt signaling proteins pGSK3β (Y216; nuclear: cc = 0.494, p < 0.001; cytoplasmic: cc = 0.488, p < 0.001) and β-catenin (nuclear: cc = 0.267, p = 0.001; cytoplasmic: cc = 0.291, p < 0.001). In particular, high levels of PAF-AH were found in tumor tissue and in the serum of BRCA1 mutation carriers. By in vitro expression analysis, a relevant gene and protein expression of PLA2G7/PAF-AH was detected exclusively in the BRCA1-negative ovarian cancer cell line UWB1.289 (p < 0.05). Functional assays showed enhanced viability, proliferation, and motility of UWB1.289 cells when PLA2G7/PAF-AH was downregulated, which underlines its protective character. Interestingly, by siRNA knockdown of PLA2G7/PAF-AH, the immunocytochemistry staining pattern of β-catenin changed from a predominantly membranous expression to a nuclear one, suggesting a negative regulatory role of PAF-AH on the Wnt/β-catenin pathway. Our data provide evidence that PAF-AH is a positive prognostic factor with functional impact, which seems particularly relevant in BRCA1 mutant ovarian cancer. For the first time, we show that its protective character may be mediated by a negative regulation of the Wnt/β-catenin pathway. Further studies need to specify this effect. Potential use of PAF-AH as a biomarker for predicting the disease risk of BRCA1 mutation carriers and for the prognosis of patients with BRCA1-negative ovarian cancer should be explored.

Consumption of Enriched Yogurt with PAF Inhibitors from Olive Pomace Affects the Major Enzymes of PAF Metabolism: A Randomized, Double Blind, Three Arm Trial

Platelet-activating factor (PAF), a proinflammatory lipid mediator, plays a crucial role in the formation of the atherosclerotic plaque. Therefore, the inhibition of endothelium inflammation by nutraceuticals, such as PAF inhibitors, is a promising alternative for preventing cardiovascular diseases. The aim of the present study was to evaluate the impact of a new functional yogurt enriched with PAF inhibitors of natural origin from olive oil by-products on PAF metabolism. Ninety-two apparently healthy, but mainly overweight volunteers (35–65 years) were randomly allocated into three groups by block-randomization. The activities of PAF’s biosynthetic and catabolic enzymes were measured, specifically two isoforms of acetyl-CoA:lyso-PAF acetyltransferase (LPCATs), cytidine 5′-diphospho-choline:1-alkyl-2-acetyl-sn-glycerol cholinephosphotransferase (PAF-CPT) and two isoforms of platelet activating factor acetylhydrolase in leucocytes (PAF-AH) and plasma (lipoprotein associated phospholipase-A2, LpPLA2). The intake of the enriched yogurt resulted in reduced PAF-CPT and LpPLA2 activities. No difference was observed in the activities of the two isoforms of lyso PAF-AT. In conclusion, intake of yogurt enriched in PAF inhibitors could favorably modulate PAF biosynthetic and catabolic pathways.

Differential expression of platelet activating factor acetylhydrolase 1b in cancers of the breast.

Breast cancer affects women at relatively high frequency (1). We mined published microarray datasets (2, 3) to determine in an unbiased fashion and at the systems level genes most differentially expressed in the primary tumors of patients with breast cancer. We report here significant differential expression of the gene encoding platelet activating factor acetylhydrolase 1b, PAFAH1B3, when comparing primary tumors of the breast to the tissue of origin, the normal breast. PAFAH1B3 mRNA was present at significantly higher quantities in tumors of the breast as compared to normal breast tissue. Analysis of human survival data revealed that expression of PAFAH1B3 in primary tumors of the breast was correlated with overall survival in patients with luminal A and luminal B type cancers. PAFAH1B3 may be of relevance to initiation, maintenance or progression of cancers of the female breast.

Lysophosphatidylcholine 16:0, a Promising Biomarker for Severe Fibromyalgia

Fibromyalgia (FM) is a complex disease without any clear physiopathology, thus treating FM remains challenging for physicians. In this article Hung et al. propose a new mouse model of FM in which adult mice are exposed to repeated and intermittent sound stress (RISS). These stressors are shown to have an effect at the cellular level: leucocytes generate a high amount of reactive oxygen species (ROS), which triggers plasma lipid peroxidation and an excessive production of lysophosphatidylcholine (LPC) 16:0. LPC16:0 molecules then activate acid-sensing ion channel 3 (ASIC3) on muscle nociceptors, generating a central sensitization process responsible for the development of FM-like phenotypes (hyperalgesia, chronic fatigue, and anxiety). In the second part, a clinical investigation was performed on patients suffering from mild and severe FM. During the month preceding the study, FM patients perceived more daily stressors than healthy controls (HC). In severe FM patients, LPC16:0 levels are correlated with ongoing pain severity. This study suggests that LPC16:0 could be a biomarker for FM, particularly in its severe forms, and proposes to further investigate the effects of platelet-activating factor acetylhydrolase (PAF-AH) inhibitors such as darapladib on fibromyalgia. These molecules could prove to be interesting therapeutic compounds for the treatment of severe FM.

Platelet-activating factor acetylhydrolase 1B catalytic gamma subunit, PAFAH1B3, is a differentially expressed gene in brain metastatic human breast cancer.

Metastasis to the brain is a clinical problem in patients with breast cancer (1-3). We mined published microarray data (4, 5) to compare primary and metastatic tumor transcriptomes for the discovery of genes associated with brain metastasis in humans with metastatic breast cancer. We found that platelet-activating factor acetylhydrolase 1B catalytic gamma subunit, encoded by PAFAH1B3, was among the genes whose expression was most different in the brain metastases of patients with metastatic breast cancer as compared to primary tumors of the breast. PAFAH1B3 mRNA was present at increased quantities in brain metastatic tissues as compared to primary tumors of the breast. Importantly, expression of PAFAH1B3 in primary tumors was significantly correlated with patient recurrence-free survival. Modulation of PAFAH1B3 expression may be relevant to the biology by which tumor cells metastasize from the breast to the brain in humans with metastatic breast cancer.