Lis1 acts as a "clutch" between the ATPase and microtubule-binding domains of the dynein motor.

The lissencephaly protein Lis1 has been reported to regulate the mechanical behavior of cytoplasmic dynein, the primary minus-end-directed microtubule motor. However, the regulatory mechanism remains poorly understood. Here, we address this issue using purified proteins from Saccharomyces cerevisiae and a combination of techniques, including single-molecule imaging and single-particle electron microscopy. We show that rather than binding to the main ATPase site within dynein's AAA+ ring or its microtubule-binding stalk directly, Lis1 engages the interface between these elements. Lis1 causes individual dynein motors to remain attached to microtubules for extended periods, even during cycles of ATP hydrolysis that would canonically induce detachment. Thus, Lis1 operates like a "clutch" that prevents dynein's ATPase domain from transmitting a detachment signal to its track-binding domain. We discuss how these findings provide a conserved mechanism for dynein functions in living cells that require prolonged microtubule attachments.

Lis1-dynein drives corona compaction and limits erroneous microtubule attachment at kinetochores.

Mitotic cell division requires that kinetochores form microtubule attachments that can segregate chromosomes and control mitotic progression via the spindle assembly checkpoint. During prometaphase, kinetochores shed a domain called the fibrous corona as microtubule attachments form. This shedding is mediated, in part, by the minus-end directed motor dynein, which 'strips' cargoes along K-fibre microtubules. Despite its essentiality, little is known about how dynein stripping is regulated and how it responds to attachment maturation. Lis1 (also known as PAFAH1B1) is a conserved dynein regulator that is mutated in the neurodevelopmental disease lissencephaly. Here, we have combined loss-of-function studies, high-resolution imaging and separation-of-function mutants to define how Lis1 contributes to dynein-mediated corona stripping in HeLa cells. Cells depleted of Lis1 fail to disassemble the corona and show a delay in metaphase as a result of persistent checkpoint activation. Furthermore, we find that although kinetochore-tethered Lis1-dynein is required for error-free microtubule attachment, the contribution of Lis1 to corona disassembly can be mediated by a cytoplasmic pool. These findings support the idea that Lis1 drives dynein function at kinetochores to ensure corona disassembly and prevent chromosome mis-segregation.

Melatonin suppresses atherosclerosis by ferroptosis inhibition via activating NRF2 pathway.

Melatonin (MLT), a conserved small indole compound, exhibits anti-inflammatory and antioxidant properties, contributing to its cardioprotective effects. Lipoprotein-associated phospholipase A2 (Lp-PLA2) is associated with atherosclerosis disease risk, and is known as an atherosclerosis risk biomarker. This study aimed to investigate the impact of MLT on Lp-PLA2 expression in the atherosclerotic process and explore the underlying mechanisms involved. In vivo, ApoE-/- mice were fed a high-fat diet, with or without MLT administration, after which the plaque area and collagen content were assessed. Macrophages were pretreated with MLT combined with ox-LDL, and the levels of ferroptosis-related proteins, NRF2 activation, mitochondrial function, and oxidative stress were measured. MLT administration significantly attenuated atherosclerotic plaque progression, as evidenced by decreased plaque area and increased collagen. Compared with those in the high-fat diet (HD) group, the levels of glutathione peroxidase 4 (GPX4) and SLC7A11 (xCT, a cystine/glutamate transporter) in atherosclerotic root macrophages were significantly increased in the MLT group. In vitro, MLT activated the nuclear factor-E2-related Factor 2 (NRF2)/SLC7A11/GPX4 signaling pathway, enhancing antioxidant capacity while reducing lipid peroxidation and suppressing Lp-PLA2 expression in macrophages. Moreover, MLT reversed ox-LDL-induced ferroptosis, through the use of ferrostatin-1 (a ferroptosis inhibitor) and/or erastin (a ferroptosis activator). Furthermore, the protective effects of MLT on Lp-PLA2 expression, antioxidant capacity, lipid peroxidation, and ferroptosis were decreased in ML385 (a specific NRF2 inhibitor)-treated macrophages and in AAV-sh-NRF2 treated ApoE-/- mice. MLT suppresses Lp-PLA2 expression and atherosclerosis processes by inhibiting macrophage ferroptosis and partially activating the NRF2 pathway.

Ndel1 disfavors dynein-dynactin-adaptor complex formation in two distinct ways.

Dynein is the primary minus-end-directed microtubule motor protein. To achieve activation, dynein binds to the dynactin complex and an adaptor to form the "activated dynein complex." The protein Lis1 aids activation by binding to dynein and promoting its association with dynactin and the adaptor. Ndel1 and its paralog Nde1 are dynein- and Lis1-binding proteins that help control dynein localization within the cell. Cell-based assays suggest that Ndel1-Nde1 also work with Lis1 to promote dynein activation, although the underlying mechanism is unclear. Using purified proteins and quantitative binding assays, here we found that the C-terminal region of Ndel1 contributes to dynein binding and negatively regulates binding to Lis1. Using single-molecule imaging and protein biochemistry, we observed that Ndel1 inhibits dynein activation in two distinct ways. First, Ndel1 disfavors the formation of the activated dynein complex. We found that phosphomimetic mutations in the C-terminal domain of Ndel1 increase its ability to inhibit dynein-dynactin-adaptor complex formation. Second, we observed that Ndel1 interacts with dynein and Lis1 simultaneously and sequesters Lis1 away from its dynein-binding site. In doing this, Ndel1 prevents Lis1-mediated dynein activation. Together, our work suggests that in vitro, Ndel1 is a negative regulator of dynein activation, which contrasts with cellular studies where Ndel1 promotes dynein activity. To reconcile our findings with previous work, we posit that Ndel1 functions to scaffold dynein and Lis1 together while keeping dynein in an inhibited state. We speculate that Ndel1 release can be triggered in cellular settings to allow for timed dynein activation.

Lis1 mutation prevents basal radial glia-like cell production in the mouse.

Human cerebral cortical malformations are associated with progenitor proliferation and neuronal migration abnormalities. Progenitor cells include apical radial glia, intermediate progenitors and basal (or outer) radial glia (bRGs or oRGs). bRGs are few in number in lissencephalic species (e.g. the mouse) but abundant in gyrencephalic brains. The LIS1 gene coding for a dynein regulator, is mutated in human lissencephaly, associated also in some cases with microcephaly. LIS1 was shown to be important during cell division and neuronal migration. Here, we generated bRG-like cells in the mouse embryonic brain, investigating the role of Lis1 in their formation. This was achieved by in utero electroporation of a hominoid-specific gene TBC1D3 (coding for a RAB-GAP protein) at mouse embryonic day (E) 14.5. We first confirmed that TBC1D3 expression in wild-type (WT) brain generates numerous Pax6+ bRG-like cells that are basally localized. Second, using the same approach, we assessed the formation of these cells in heterozygote Lis1 mutant brains. Our novel results show that Lis1 depletion in the forebrain from E9.5 prevented subsequent TBC1D3-induced bRG-like cell amplification. Indeed, we observe perturbation of the ventricular zone (VZ) in the mutant. Lis1 depletion altered adhesion proteins and mitotic spindle orientations at the ventricular surface and increased the proportion of abventricular mitoses. Progenitor outcome could not be further altered by TBC1D3. We conclude that disruption of Lis1/LIS1 dosage is likely to be detrimental for appropriate progenitor number and position, contributing to lissencephaly pathogenesis.

Lp-PLA2 (Lipoprotein-Associated Phospholipase A2) Deficiency Lowers Cholesterol Levels and Protects Against Atherosclerosis in Rabbits.

BACKGROUND: Elevated plasma Lp-PLA2 (lipoprotein-associated phospholipase A2) activity is closely associated with an increased risk of cardiovascular events. However, whether and how Lp-PLA2 is directly involved in the pathogenesis of atherosclerosis is still unclear. To examine the hypothesis that Lp-PLA2 could be a potential preventative target of atherosclerosis, we generated Lp-PLA2 knockout rabbits and investigated the pathophysiological functions of Lp-PLA2. METHODS: Lp-PLA2 knockout rabbits were generated using CRISPR/Cas9 system to assess the role of Lp-PLA2 in plasma lipids regulation and identify its underlying molecular mechanisms. Homozygous knockout rabbits along with wild-type rabbits were fed a cholesterol-rich diet for up to 14 weeks and their atherosclerotic lesions were compared. Moreover, the effects of Lp-PLA2 deficiency on the key cellular behaviors in atherosclerosis were assessed in vitro. RESULTS: When rabbits were fed a standard diet, Lp-PLA2 deficiency led to a significant reduction in plasma lipids. The decreased protein levels of SREBP2 (sterol regulatory element-binding protein 2) and HMGCR (3-hydroxy-3-methylglutaryl coenzyme A reductase) in livers of homozygous knockout rabbits indicated that the cholesterol biosynthetic pathway was impaired with Lp-PLA2 deficiency. In vitro experiments further demonstrated that intracellular Lp-PLA2 efficiently enhanced SREBP2-related cholesterol biosynthesis signaling independently of INSIGs (insulin-induced genes). When fed a cholesterol-rich diet, homozygous knockout rabbits exhibited consistently lower level of hypercholesterolemia, and their aortic atherosclerosis lesions were significantly reduced by 60.2% compared with those of wild-type rabbits. The lesions of homozygous knockout rabbits were characterized by reduced macrophages and the expression of inflammatory cytokines. Macrophages of homozygous knockout rabbits were insensitive to M1 polarization and showed reduced DiI-labeled lipoprotein uptake capacity compared with wild-type macrophages. Lp-PLA2 deficiency also inhibited the adhesion between monocytes and endothelial cells. CONCLUSIONS: These results demonstrate that Lp-PLA2 plays a causal role in regulating blood lipid homeostasis and Lp-PLA2 deficiency protects against dietary cholesterol-induced atherosclerosis in rabbits. Lp-PLA2 could be a potential target for the prevention of atherosclerosis.

Exosomal miR-93-5p from cancer-associated fibroblasts confers malignant phenotypes on bladder cancer cells by targeting PAFAH1B1.

BACKGROUND: Dysregulation of cancer-associated fibroblasts (CAFs) still greatly challenges the treatments for bladder cancer (BC), where exosomal miRNAs derived from CAFs are one of the essential effectors for tumor progression. miR-93-5p is reported to be upregulated in BC, however, it is barely investigated in BC-derived CAFs. METHOD: The CAF markers were immunofluorescent-labeled and examined by western blotting assay in CAFs and normal fibroblasts (NFs). CAFs- and NFs-derived exosomes (CAFs-exo/NFs-exo) were authenticated by transmission electron microscope and nanoparticle tracking analysis. Cell viability was determined by cell counting kit-8 assay, and cell mobility was evaluated by wound healing and transwell assays. Real-time quantitative PCR was used to quantify the RNA expressions, and a western blotting assay was used for protein expression. Interaction between miR-93-5p and Platelet-Activating Factor Acetylhydrolase IB Subunit Beta (PAFAH1B1) was verified by luciferase reporter assay. HE staining assay was applied to assess the histological changes of xenografts. RESULTS: CAFs-exo notably enhanced cell mobility and the expression levels of miR-93-5p of BC cells compared to NFs-exo. However, inhibition of miR-93-5p in CAFs-exo exhibited attenuated pro-metastatic ability on BC cells. PAFAH1B1 was one of the predicted targets of miR-93-5p, whose mRNA level was most significantly downregulated after miR-93-5p transfection. The interaction between PAFAH1B1 and miR-93-5p was verified, and miR-93-5p negatively regulated the protein level of PAFAH1B1. Overexpression of PAFAH1B1 could efficiently reverse the effects of miR-93-5p mimic on BC cell mobility. Finally, inhibition of miR-93-5p was proved to impair the carcinogenic function of CAFs-exo in vivo . CONCLUSION: Exosomal miR-93-5p derived from CAFs confers oncogenicity on BC cells via sponging PAFAH1B1, suggesting a novel therapeutic strategy for BC.

Neuroepithelial stem cell proliferation requires LIS1 for precise spindle orientation and symmetric division.

Mitotic spindle orientation and plane of cleavage in mammals is a determinant of whether division yields progenitor expansion and/or birth of new neurons during radial glial progenitor cell (RGPC) neurogenesis, but its role earlier in neuroepithelial stem cells is poorly understood. Here we report that Lis1 is essential for precise control of mitotic spindle orientation in both neuroepithelial stem cells and radial glial progenitor cells. Controlled gene deletion of Lis1 in vivo in neuroepithelial stem cells, where cleavage is uniformly vertical and symmetrical, provokes rapid apoptosis of those cells, while radial glial progenitors are less affected. Impaired cortical microtubule capture via loss of cortical dynein causes astral and cortical microtubules to be greatly reduced in Lis1-deficient cells. Increased expression of the LIS/dynein binding partner NDEL1 restores cortical microtubule and dynein localization in Lis1-deficient cells. Thus, control of symmetric division, essential for neuroepithelial stem cell proliferation, is mediated through spindle orientation determined via LIS1/NDEL1/dynein-mediated cortical microtubule capture.

Human knockouts and phenotypic analysis in a cohort with a high rate of consanguinity.

A major goal of biomedicine is to understand the function of every gene in the human genome. Loss-of-function mutations can disrupt both copies of a given gene in humans and phenotypic analysis of such 'human knockouts' can provide insight into gene function. Consanguineous unions are more likely to result in offspring carrying homozygous loss-of-function mutations. In Pakistan, consanguinity rates are notably high. Here we sequence the protein-coding regions of 10,503 adult participants in the Pakistan Risk of Myocardial Infarction Study (PROMIS), designed to understand the determinants of cardiometabolic diseases in individuals from South Asia. We identified individuals carrying homozygous predicted loss-of-function (pLoF) mutations, and performed phenotypic analysis involving more than 200 biochemical and disease traits. We enumerated 49,138 rare (<1% minor allele frequency) pLoF mutations. These pLoF mutations are estimated to knock out 1,317 genes, each in at least one participant. Homozygosity for pLoF mutations at PLA2G7 was associated with absent enzymatic activity of soluble lipoprotein-associated phospholipase A2; at CYP2F1, with higher plasma interleukin-8 concentrations; at TREH, with lower concentrations of apoB-containing lipoprotein subfractions; at either A3GALT2 or NRG4, with markedly reduced plasma insulin C-peptide concentrations; and at SLC9A3R1, with mediators of calcium and phosphate signalling. Heterozygous deficiency of APOC3 has been shown to protect against coronary heart disease; we identified APOC3 homozygous pLoF carriers in our cohort. We recruited these human knockouts and challenged them with an oral fat load. Compared with family members lacking the mutation, individuals with APOC3 knocked out displayed marked blunting of the usual post-prandial rise in plasma triglycerides. Overall, these observations provide a roadmap for a 'human knockout project', a systematic effort to understand the phenotypic consequences of complete disruption of genes in humans.

A Complex of Type I Platelet-Activating Factor Acetylhydrolase (PAF-AH) Catalytic Subunits Switches from α1/α2 Heterodimer to α2/α2 Homodimer during Adipocyte Differentiation of 3T3-L1 Cells.

Platelet-activating factor acetylhydrolase (PAF-AH) hydrolyzes an acetyl ester at the sn-2 position of platelet-activating factor (PAF), thereby mediating a variety of biological functions. PAF-AH is found in three isoforms: Type I PAF-AH (PAF-AH I) and Type II PAF-AH (PAF-AH II) are intracellular enzymes whereas plasma PAF-AH is characterized by association with lipoprotein in plasma. PAF-AH I forms a tetramer constituted by two catalytic subunits (α1 and α2) with ß regulatory subunits. We recently showed that a deficiency of PAF-AH I catalytic subunits in male mice caused an increase of body weight, food intake, and white adipose tissue (WAT) weight. In this study, we examined whether the expression of this enzyme was altered in the differentiation of 3T3-L1 preadipocytes into adipocytes. The amount of PAF-AH I α1 subunit protein was significantly reduced in 3T3-L1 differentiation, while the amount of the PAF-AH I α2 subunit was not changed. Immunoprecipitation analysis of 3T3-L1 differentiation showed that the complex of PAF-AH I catalytic subunits was changed from α1/α2 heterodimer to α2/α2 homodimer. Our findings suggest that changes in PAF-AH I catalytic subunits are involved in adipocyte differentiation of 3T3-L1 and obesity in mice.

Integrated analysis of single-cell and bulk RNA sequencing reveals pro-fibrotic PLA2G7high macrophages in pulmonary fibrosis.

Pulmonary fibrosis (PF) is the pathological change of end-stage interstitial lung diseases with high mortality and limited therapeutic options. Lung macrophages have distinct subsets with divergent functions, and play critical roles in the pathogenesis of PF. In this study, integrative analysis of lung single-cell and bulk RNA-seq data from patients with fibrotic hypersensitivity pneumonitis and idiopathic pulmonary fibrosis was utilized to identify particular macrophage subsets during the development of PF. We find a specific macrophage subpopulation highly expressing PLA2G7 in fibrotic lungs. We performed additional single-cell RNA-seq analysis to identify analogous macrophage population in bleomycin (BLM)-induced mouse pulmonary fibrosis models. By in vitro and in vivo experiments, we further reveal the pro-fibrotic role for this PLA2G7high macrophage subset in fibroblast-to-myofibroblast transition (FMT) during pulmonary fibrosis. PLA2G7 promotes FMT via LPC/ATX/LPA/LPA2 axis in macrophages. Moreover, PLA2G7 is regulated by STAT1, and pharmacological inhibition of PLA2G7 by Darapladib ameliorates pulmonary fibrosis in BLM-induced mice. The results of this study support the view that PLA2G7high macrophage subpopulation contributes importantly to the pathogenesis of PF, which provides a potential way for targeted therapy.

Novel frameshift mutation in LIS1 gene is a probable cause of lissencephaly: a case report.

BACKGROUND: Lissencephaly (LIS) is a cortical malformation, characterized by smooth or nearly smooth cerebral surface and a shortage of gyral and sulcal development, which is caused by deficient neuronal migration during embryogenesis. Neuronal migration involves many gene products, among which is the product of the PAFAH1B1 gene, associated with this disease. LIS is a rare disease, characterized by low population frequency, and with non-specific clinical symptoms such as early epilepsy, developmental delay or cerebral palsy-like motor problems. Given that high-throughput sequencing techniques have been improving diagnosis, we have chosen this technique for addressing this patient. CASE PRESENTATION: We present the case of a seven years old male patient with an undiagnosed rare disease, with non-specific clinical symptoms possibly compatible with lissencephaly. The patient was enrolled in a study that included the sequencing of his whole genome. Sequence data was analyzed following a bioinformatic pipeline. The variants obtained were annotated and then subjected to different filters for prioritization. Also mitochondrial genome was analyzed. A novel candidate frameshift insertion in known PAFAH1B1 gene was found, explaining the index case phenotype. The assessment through in silico tools reported that it causes nonsense mediated mechanisms and that it is damaging with high confidence scores. The insertion causes a change in the reading frame, and produces a premature stop codon, severely affecting the protein function and probably the silencing of one allele. The healthy mother did not carry the mutation, and the unaffected father was not available for analysis. CONCLUSIONS: Through this work we found a novel de novo mutation in LIS1/PAFAH1B1 gene, as a likely cause of a rare disease in a young boy with non-specific clinical symptoms. The mutation found correlates with the phenotype studied since the loss of function in the gene product has already been described in this condition. Since there are no other variants in the PAFAH1B1 gene with low population frequency and due to family history, a de novo disease mechanism is proposed.

Structural Consequence of Non-Synonymous Single-Nucleotide Variants in the N-Terminal Domain of LIS1.

Disruptive neuronal migration during early brain development causes severe brain malformation. Characterized by mislocalization of cortical neurons, this condition is a result of the loss of function of migration regulating genes. One known neuronal migration disorder is lissencephaly (LIS), which is caused by deletions or mutations of the LIS1 (PAFAH1B1) gene that has been implicated in regulating the microtubule motor protein cytoplasmic dynein. Although this class of diseases has recently received considerable attention, the roles of non-synonymous polymorphisms (nsSNPs) in LIS1 on lissencephaly progression remain elusive. Therefore, the present study employed combined bioinformatics and molecular modeling approach to identify potential damaging nsSNPs in the LIS1 gene and provide atomic insight into their roles in LIS1 loss of function. Using this approach, we identified three high-risk nsSNPs, including rs121434486 (F31S), rs587784254 (W55R), and rs757993270 (W55L) in the LIS1 gene, which are located on the N-terminal domain of LIS1. Molecular dynamics simulation highlighted that all variants decreased helical conformation, increased the intermonomeric distance, and thus disrupted intermonomeric contacts in the LIS1 dimer. Furthermore, the presence of variants also caused a loss of positive electrostatic potential and reduced dimer binding potential. Since self-dimerization is an essential aspect of LIS1 to recruit interacting partners, thus these variants are associated with the loss of LIS1 functions. As a corollary, these findings may further provide critical insights on the roles of LIS1 variants in brain malformation.

Prenatal diagnosis of Miller-Dieker syndrome by chromosomal microarray.

OBJECTIVE: To assess the experience on prenatal diagnosis of Miller-Dieker syndrome (MDS) to further delineate the fetal presentation of this syndrome. METHODS: This was a retrospective study. Fetal MDS was diagnosed prenatally by chromosomal microarray (CMA). Clinical data were reviewed for these cases, including maternal characteristics, indications for prenatal diagnosis, sonographic findings, CMA results, and pregnancy outcomes. RESULTS: Four cases were diagnosis as MDS by CMA. The most common sonographic features were ventriculomegaly (3/4) and polyhydramnios (2/4). Deletion sizes ranged from 1.5 to 5.4 Mb. All microdeletions were located at the MDS critical region and showed haploinsufficiency of the YWHAE, CRK, and PAFAH1B1. All patients chose to terminate the pregnancy. Parental chromosome analysis were preformed in three cases and demonstrated that two cases were de novo and one case was caused by inherited derivative chromosomes from parental balanced translocations. CONCLUSION: The most common prenatal ultrasound findings of MDS were ventriculomegaly and polyhydramnios. CMA can improve diagnostic precision for detecting MDS.

Silencing linc00662 inhibits cell proliferation and colony formation of lung cancer cells via regulating the miR-145-5p-PAFAH1B2 axis.

Lung cancer is the most common cause of cancer-related death in the world. Long non-coding RNAs (lncRNAs) are longer than 200 nucleotide transcripts, and are not translated into protein. The lncRNA linc00662 is overexpressed in lung cancer; however, its role in lung cancer is still unknown. In our study, by analyzing the TCGA data, we found that linc00662 was overexpressed in lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC). We knocked-down the expression of linc00662 using siRNA, and found that silencing linc00662 significantly inhibited the proliferation and colony formation of the lung cancer cell lines A549 and H460. We also found that knockdown of linc00662 increased the expression of the microRNA miR-145-5p and decreased the expression of the platelet-activating factor acetylhydrolase IB subunit beta (PAFAH1B2) gene. We further show that linc00662 binds with miR-145-5p, and that miR-145-5p binds to the 3'UTR of PAFAH1B2. miR-145-5p negatively regulates PAFAH1B2 both at the mRNA and the protein level. Loss of miR-145-5p abolished the inhibitory effects of silencing linc00662 on the proliferation and colony formation of A549 and H460 cells. These findings indicate that linc00662 functions as an oncogene by acting as a competing endogenous RNA (ceRNA) and sponges and regulates miR-145-5p in lung cancer, and thus may provide a potential target for treating lung cancer.

Identification of PLA2G7 as a novel biomarker of diffuse large B cell lymphoma.

BACKGROUND: Diffuse large B-cell lymphoma is the most common form of non-Hodgkin lymphoma globally, and patients with relapsed or refractory DLBCL typically experience poor long-term outcomes. METHODS: Differentially expressed genes associated with DLBCL were identified using two GEO datasets in an effort to detect novel diagnostic or prognostic biomarkers of this cancer type, after which receiver operating characteristic curve analyses were conducted. Genes associated with DLBCL patient prognosis were additionally identified via WCGNA analyses of the TCGA database. The expression of PLA2G7 in DLBCL patient clinical samples was further assessed, and the functional role of this gene in DLBCL was assessed through in vitro and bioinformatics analyses. RESULTS: DLBCL-related DEGs were found to be most closely associated with immune responses, cell proliferation, and angiogenesis. WCGNA analyses revealed that PLA2G7 exhibited prognostic value in DLBCL patients, and the upregulation of this gene in DLBCL patient samples was subsequently validated. PLA2G7 was also found to be closely linked to tumor microenvironmental composition such that DLBCL patients expressing higher levels of this gene exhibited high local monocyte and gamma delta T cell levels. In vitro experiments also revealed that knocking down PLA2G7 expression was sufficient to impair the migration and proliferation of DLBCL cells while promoting their apoptotic death. Furthmore, the specific inhibitor of PLA2G7, darapladib, could noticeably restrained the DLBCL cell viability and induced apoptosis. CONCLUSIONS: PLA2G7 may represent an important diagnostic, prognostic, or therapeutic biomarker in patients with DLBCL.

Pathogenic variants identified by whole-exome sequencing in 43 patients with epilepsy.

BACKGROUND: Epilepsy is a group of neurological disorders characterized by recurrent epileptic seizures. Epilepsy is affected by many factors, approximately 20-30% of cases are caused by acquired conditions, but in the remaining cases, genetic factors play an important role. Early establishment of a specific diagnosis is important to treat and manage this disease. METHODS: In this study, we have recruited 43 epileptic encephalopathy patients and the molecular genetic analysis of those children was performed by whole-exome sequencing (WES). RESULTS: Fourteen patients (32.6%, 14/43) had positive genetic diagnoses, including fifteen mutations in fourteen genes. The overall diagnostic yield was 32.6%. A total of 9 patients were diagnosed as pathogenic mutations, including 4 variants had been reported as pathogenic previously and 6 novel variants that had not been reported previously. Therefore, WES heralds promise as a tool for clinical diagnosis of patients with genetic disease. CONCLUSION: Early establishment of a specific diagnosis, on the one hand, is necessary for providing an accurate prognosis and recurrence risk as well as optimizing management and treatment options. On the other hand, to unveil the genetic architecture of epilepsy, it is of vital importance to investigate the phenotypic and genetic complexity of epilepsy.

Deficiency of Type I Platelet-Activating Factor-Acetylhydrolase Catalytic Subunits Causes an Increase in Body Weight.

Type I platelet-activating factor-acetylhydrolase (PAF-AH) forms a complex consisting of two catalytic subunits (α1 and/or α2) with a regulatory subunit (ß). Although this protein was discovered as an enzyme that degrades an acetyl ester linked at the sn-2 position of platelet-activating factor (PAF), its physiological function remains unknown. In this study, to examine whether knockout mice lacking the catalytic subunits of this enzyme showed a different phenotype from that of wild-type mice, we measured and compared the body weights of knockout mice and control mice. The body weights of knockout mice were significantly increased compared to those of the control mice during 6 to 20 weeks from birth. Food intake was also significantly increased in knockout mice compared with control mice during these periods. Since a decrease in testis weight was reported in the knockout mice, we expected a decrease in testosterone levels. We measured and compared the amounts of testosterone in the serum and testis of knockout and control mice using liquid chromatography-tandem mass spectrometry, and found that testosterone levels in both the serum and testis were significantly decreased in the knockout mice compared with the control mice. These results suggest that a deficiency of type I PAF-AH catalytic subunits causes an increase in body weight, in part, due to reduced testosterone levels in male mice.

[Prenatal diagnosis and genetic analysis of a fetus with Miller-Dieker syndrome].

OBJECTIVE: To explore the genetic basis for a fetus with lissencephaly. METHODS: Genomic DNA was extracted from amniotic fluid sample and subjected to copy number variation (CNV) analysis. RESULTS: The fetus was found to harbor a heterozygous 5.2 Mb deletion at 17p13.3p13.2, which encompassed the whole critical region of Miller-Dieker syndrome (MDS) (chr17: 1-2 588 909). CONCLUSION: The fetus was diagnosed with MDS. Deletion of the PAFAH1B1 gene may account for the lissencephaly found in the fetus.

Lipoprotein-associated phospholipase A2: The story continues.

Inflammation is thought to play an important role in the pathogenesis of vascular diseases. Lipoprotein-associated phospholipase A2 (Lp-PLA2) mediates vascular inflammation through the regulation of lipid metabolism in blood, thus, it has been extensively investigated to identify its role in vascular inflammation-related diseases, mainly atherosclerosis. Although darapladib, the most advanced Lp-PLA2 inhibitor, failed to meet the primary endpoints of two large phase III trials in atherosclerosis patients cotreated with standard medical care, the research on Lp-PLA2 has not been terminated. Novel pathogenic, epidemiologic, genetic, and crystallographic studies regarding Lp-PLA2 have been reported recently, while novel inhibitors were identified through a fragment-based lead discovery strategy. More strikingly, recent clinical and preclinical studies revealed that Lp-PLA2 inhibition showed promising therapeutic effects in diabetic macular edema and Alzheimer's disease. In this review, we not only summarized the knowledge of Lp-PLA2 established in the past decades but also emphasized new findings in recent years. We hope this review could be valuable for helping researchers acquire a much deeper insight into the nature of Lp-PLA2, identify more potent and selective Lp-PLA2 inhibitors, and discover the potential indications of Lp-PLA2 inhibitors.