Loss of Down syndrome critical region-1 leads to cholesterol metabolic dysfunction that exaggerates hypercholesterolemia in ApoE-null background.

Down syndrome critical region (DSCR)-1 functions as a feedback modulator for calcineurin-nuclear factor for activated T cell (NFAT) signals, which are crucial for cell proliferation and inflammation. Stable expression of DSCR-1 inhibits pathological angiogenesis and septic inflammation. DSCR-1 also plays a critical role in vascular wall remodeling associated with aneurysm development that occurs primarily in smooth muscle cells. Besides, Dscr-1 deficiency promotes the M1-to M2-like phenotypic switch in macrophages, which correlates to the reduction of denatured cholesterol uptakes. However, the distinct roles of DSCR-1 in cholesterol and lipid metabolism are not well understood. Here, we show that loss of apolipoprotein (Apo) E in mice with chronic hypercholesterolemia induced Dscr-1 expression in the liver and aortic atheroma. In Dscr-1-null mice fed a high-fat diet, oxidative- and endoplasmic reticulum (ER) stress was induced, and sterol regulatory element-binding protein (SREBP) 2 production in hepatocytes was stimulated. This exaggerated ApoE-/--mediated nonalcoholic fatty liver disease (NAFLD) and subsequent hypercholesterolemia. Genome-wide screening revealed that loss of both ApoE and Dscr-1 resulted in the induction of immune- and leukocyte activation-related genes in the liver compared with ApoE deficiency alone. However, expressions of inflammation-activated markers and levels of monocyte adhesion were suspended upon induction of the Dscr-1 null background in the aortic endothelium. Collectively, our study shows that the combined loss of Dscr-1 and ApoE causes metabolic dysfunction in the liver but reduces atherosclerotic plaques, thereby leading to a dramatic increase in serum cholesterol and the formation of sporadic vasculopathy.

Detailed analysis of Japanese patients with adenosine deaminase 2 deficiency reveals characteristic elevation of type II interferon signature and STAT1 hyperactivation.

BACKGROUND: Deficiency of adenosine deaminase 2 (DADA2) is an autosomal recessive inflammatory disease caused by loss-of-function mutations in both alleles of the ADA2 gene. Most patients with DADA2 exhibit systemic vasculopathy consistent with polyarteritis nodosa, but large phenotypic variability has been reported, and the pathogenesis of DADA2 remains unclear. OBJECTIVES: This study sought to assess the clinical and genetic characteristics of Japanese patients with DADA2 and to gain insight into the pathogenesis of DADA2 by multi-omics analysis. METHODS: Clinical and genetic data were collected from 8 Japanese patients with DADA2 diagnosed between 2016 and 2019. ADA2 variants in this cohort were functionally analyzed by in vitro overexpression analysis. PBMCs from 4 patients with DADA2 were subjected to transcriptome and proteome analyses. Patient samples were collected before and after introduction of anti- TNF-α therapies. Transcriptome data were compared with those of normal controls and patients with other autoinflammatory diseases. RESULTS: Five novel ADA2 variants were identified in these 8 patients and were confirmed pathogenic by in vitro analysis. Anti-TNF-α therapy controlled inflammation in all 8 patients. Transcriptome and proteome analyses showed that upregulation of type II interferon signaling was characteristic of DADA2. Network analysis identified STAT1 as a key regulator and a hub molecule in DADA2 pathogenesis, a finding supported by the hyperactivation of STAT1 in patients' monocytes and B cells after IFN-γ stimulation. CONCLUSIONS: Type II interferon signaling and STAT1 are associated with the pathogenesis of DADA2.

Reference Genes across Nine Brain Areas of Wild Type and Prader-Willi Syndrome Mice: Assessing Differences in Igfbp7, Pcsk1, Nhlh2 and Nlgn3 Expression.

Prader−Willi syndrome (PWS) is a complex neurodevelopmental disorder caused by the deletion or inactivation of paternally expressed imprinted genes at the chromosomal region 15q11−q13. The PWS-critical region (PWScr) harbors tandemly repeated non-protein coding IPW-A exons hosting the intronic SNORD116 snoRNA gene array that is predominantly expressed in brain. Paternal deletion of PWScr is associated with key PWS symptoms in humans and growth retardation in mice (PWScr model). Dysregulation of the hypothalamic−pituitary axis (HPA) is thought to be causally involved in the PWS phenotype. Here we performed a comprehensive reverse transcription quantitative PCR (RT-qPCR) analysis across nine different brain regions of wild-type (WT) and PWScr mice to identify stably expressed reference genes. Four methods (Delta Ct, BestKeeper, Normfinder and Genorm) were applied to rank 11 selected reference gene candidates according to their expression stability. The resulting panel consists of the top three most stably expressed genes suitable for gene-expression profiling and comparative transcriptome analysis of WT and/or PWScr mouse brain regions. Using these reference genes, we revealed significant differences in the expression patterns of Igfbp7, Nlgn3 and three HPA associated genes: Pcsk1, Pcsk2 and Nhlh2 across investigated brain regions of wild-type and PWScr mice. Our results raise a reasonable doubt on the involvement of the Snord116 in posttranscriptional regulation of Nlgn3 and Nhlh2 genes. We provide a valuable tool for expression analysis of specific genes across different areas of the mouse brain and for comparative investigation of PWScr mouse models to discover and verify different regulatory pathways affecting this complex disorder.

Evidence that FGFRL1 contributes to congenital diaphragmatic hernia development in humans.

Fibroblast growth factor receptor-like 1 (FGFRL1) encodes a transmembrane protein that is related to fibroblast growth factor receptors but lacks an intercellular tyrosine kinase domain. in vitro studies suggest that FGFRL1 inhibits cell proliferation and promotes cell differentiation and cell adhesion. Mice that lack FGFRL1 die shortly after birth from respiratory distress and have abnormally thin diaphragms whose muscular hypoplasia allows the liver to protrude into the thoracic cavity. Haploinsufficiency of FGFRL1 has been hypothesized to contribute to the development of congenital diaphragmatic hernia (CDH) associated with Wolf-Hirschhorn syndrome. However, data from both humans and mice suggest that disruption of one copy of FGFRL1 alone is insufficient to cause diaphragm defects. Here we report a female fetus with CDH whose 4p16.3 deletion allows us to refine the Wolf-Hirschhorn syndrome CDH critical region to an approximately 1.9 Mb region that contains FGFRL1. We also report a male infant with isolated left-sided diaphragm agenesis who carried compound heterozygous missense variants in FGFRL1. These cases provide additional evidence that deleterious FGFRL1 variants may contribute to the development of CDH in humans.

Propofol exerts anticancer activity on hepatocellular carcinoma cells by raising lncRNA DGCR5.

Hepatocellular carcinoma is one of the most fatal cancers worldwide. Propofol is an intravenous anesthetic extensively used in clinical. Herein, we tested the anticancer activity of propofol on hepatocellular carcinoma, along with the internal molecular mechanism related to lncRNA DiGeorge syndrome critical region gene 5 (DGCR5). Followed by propofol stimulation, hepatocellular carcinoma Huh-7 and HepG2 cell viability, proliferation, migration, invasion, and apoptosis were tested, respectively. Then, DGCR5 expression levels in hepatocellular carcinoma tissues and cells were measured. sh-DGCR5 was transfected to silence DGCR5 expression. Subsequently, the influence of DGCR5 silence on propofol caused Huh-7 and HepG2 cell viability loss, proliferation inhibition, migration and invasion suppression, apoptosis induction, as well as Raf1/ERK1/2 and Wnt/ß-catenin pathways inactivation were assessed, respectively. We discovered that propofol declined Huh-7 and HepG2 cell viability, proliferation, migration and invasion, but increased cell apoptosis. DGCR5 had a relatively lower expression level in hepatocellular carcinoma tissues and cells. Propofol elevated DGCR5 expression in Huh-7 and HepG2 cells. Increased expression of DGCR5 was connected with the anticancer activity of propofol on Huh-7 and HepG2 cells. Besides, propofol repressed Raf1/ERK1/2 and Wnt/ß-catenin pathways through elevating DGCR5 expression. In conclusion, the anticancer activity of propofol on hepatocellular carcinoma was verified in this study. Propofol repressed hepatocellular carcinoma Huh-7 and HepG2 cell growth and metastasis at least by elevating DGCR5 and hereafter inactivating Raf1/ERK1/2 and Wnt/ß-catenin pathways.

Neuronal migration genes and a familial translocation t (3;17): candidate genes implicated in the phenotype.

BACKGROUND: While Miller-Dieker syndrome critical region deletions are well known delineated anomalies, submicroscopic duplications in this region have recently emerged as a new distinctive syndrome. So far, only few cases have been described overlapping 17p13.3 duplications. METHODS: In this study, we report on clinical and cytogenetic characterization of two new cases involving 17p13.3 and 3p26 chromosomal regions in two sisters with familial history of lissencephaly. Fluorescent In Situ Hybridization and array Comparative Genomic Hybridization were performed. RESULTS: A deletion including the critical region of the Miller-Dieker syndrome of at least 2,9 Mb and a duplication of at least 3,6 Mb on the short arm of chromosome 3 were highlighted in one case. The opposite rearrangements, 17p13.3 duplication and 3p deletion, were observed in the second case. This double chromosomal aberration is the result of an adjacent 1:1 meiotic segregation of a maternal reciprocal translocation t(3,17)(p26.2;p13.3). CONCLUSIONS: 17p13.3 and 3p26 deletions have a clear range of phenotypic features while duplications still have an uncertain clinical significance. However, we could suggest that regardless of the type of the rearrangement, the gene dosage and interactions of CNTN4, CNTN6 and CHL1 in the 3p26 and PAFAH1B1, YWHAE in 17p13.3 could result in different clinical spectrums.

Refining critical regions in 15q24 microdeletion syndrome pertaining to autism.

Chromosome 15q24 microdeletion syndrome is characterized by developmental delay, facial dysmorphism, hearing loss, hypotonia, recurrent infection, and other congenital malformations including microcephaly, scoliosis, joint laxity, digital anomalies, as well as sometimes having autism spectrum disorder (ASD) and attention deficit hyperactivity disorder. Here, we report a boy with a 2.58-Mb de novo deletion at chromosome 15q24. He is diagnosed with ASD and having multiple phenotypes similar to those reported in cases having 15q24 microdeletion syndrome. To delineate the critical genes and region that might be responsible for these phenotypes, we reviewed all previously published cases. We observe a potential minimum critical region of 650 kb (LCR15q24A-B) affecting NEO1 among other genes that might pertinent to individuals with ASD carrying this deletion. In contrast, a previously defined minimum critical region downstream of the 650-kb interval (LCR15q24B-D) is more likely associated with the developmental delay, facial dysmorphism, recurrent infection, and other congenital malformations. As a result, the ASD phenotype in this individual is potentially attributed by genes particularly NEO1 within the newly proposed critical region.

Functional Dissection of pri-miR-290~295 in Dgcr8 Knockout Mouse Embryonic Stem Cells.

The DiGeorge syndrome critical region gene 8 (Dgcr8) knockout strategy has been widely used to study the function of canonical microRNAs (miRNAs) in vitro and in vivo. However, primary miRNA (pri-miRNA) transcripts are accumulated in Dgcr8 knockout cells due to interrupted processing. Whether abnormally accumulated pri-miRNAs have any function is unknown. Here, using clustered regularly interspaced short palindromic repeats system/CRISPR-associated protein 9 (CRISPR/Cas9), we successfully knocked out the primary microRNA-290~295 (pri-miR-290~295) cluster, the most highly expressed miRNA cluster in mouse embryonic stem cells (ESCs), in Dgcr8 knockout background. We found that the major defects associated with Dgcr8 knockout in mouse ESCs, including higher expression of epithelial-to-mesenchymal transition (EMT) markers, slower proliferation, G1 accumulation, and defects in silencing self-renewal, were not affected by the deletion of pri-miR-290~290 cluster. Interestingly, the transcription of neighboring gene nucleotide-binding oligomerization domain, leucine rich repeat and pyrin domain containing 12(Nlrp12) was upregulated upon the deletion of the pri-miR-290~295 cluster. Together, our results suggested that the major defects in Dgcr8 knockout ESCs were not due to the accumulation of pri-miR-290~295, and the deletion of miRNA genes could affect the transcription of neighboring DNA elements.

LncRNA DGCR5 represses the development of hepatocellular carcinoma by targeting the miR-346/KLF14 axis.

Long non-coding RNAs (lncRNAs) are a class of regulatory noncoding RNAs. Emerging evidence highlights the critical roles of lncRNAs in the progression of hepatocellular carcinoma (HCC). Although many lncRNAs have been identified in the development of HCC, the association between DiGeorge syndrome critical region gene 5 (DGCR5) and HCC remains unclear. In the current study, we focused on the biological role of DGCR5 in HCC. We observed that DGCR5 was decreased in HCC cells, including SMCC7721, Hep3B, HepG2, MHCC-97L, MHCC-97H, and SNU449 hepatocellular carcinoma cells, compared with the normal human liver cell line THLE-3 normal human liver cells. In addition, DGCR5 overexpression could repress HCC cell growth, migration, and invasion considerably. Increasing studies have indicated the interactions between lncRNAs and microRNAs. MicroRNAs are endogenous small noncoding RNAs and they can play important roles in tumorigenesis. MicroRNA 346 (miR-346) has been demonstrated in various human cancer types, including HCC. MiR-346 was found to be increased in HCC cells and DGCR5 can act as a sponge of miR-346 to modulate the progression of HCC. The binding correlation between DGCR5 and miR-346 was validated in our research. Subsequently, Krüppel-like factor 14 (KLF14) was predicted as a downstream target of miR-346 and miR-346 can induce the development of HCC by inhibiting KLF14. Finally, we proved that DGCR5 can rescue the inhibited levels of KLF14 repressed by miR-346 mimics in MHCC-97H and Hep3B cells. Taken together, it was indicated in our study that DGCR5 can restrain the progression of HCC through sponging miR-346 and modulating KLF14 in vitro.

Small Supernumerary Marker Chromosome May Provide Information on Dosage-insensitive Pericentric Regions in Human.

BACKGROUND: Cytogenetically visible chromosomal imbalances in humans are deleterious and adverse in the majority of the cases. However, healthy persons living with chromosomal imbalances in the range of several megabasepairs (Mbps) in size, like carriers of small Supernumerary Marker Chromosomes (sSMCs) exist. MATERIALS & METHODS: The identification of healthy sSMC carriers with euchromatic centromere-near (ECN) imbalances led to the following proposal: ECN-regions do not contain any dosage sensitive genes. Due to own previous work, dosage-insensitive pericentric ECN-regions were already determined with an accuracy of 0.3 and 5 Mbp. Based on this data we established 43 new pericentromeric probe sets spanning about 3-5 Mbp of each euchromatic human chromosome arm starting from the known insensitive regions towards distal. Such so called pericentromeric-critical region fluorescence in situ hybridization (PeCR-FISH) probe sets were applied exemplarily and successful here in 15 sSMC cases as available from the Else Kröner-Fresenius-sSMC-cellbank . CONCLUSION: Most of the involved sSMC breakpoints could be characterized as a higher resolution than before. An unexpected result was that in 5/15 cases cryptic mosaicism was characterized. The latter is also to be considered to have potentially an influence on the clinical outcome in these so-called discontinuous sSMCs. Overall, the suitability of PeCR-FISH to characterize sSMCs was proven; the potential of this probe set to further delineate sizes of dosage insensitive pericentric regions is obvious but dependent on suited cases. Furthermore, discontinuous sSMCs can be identified by this approach and this new subtype of sSMC needs to be studied in more detail in future.

Evidence that increased Kcnj6 gene dose is necessary for deficits in behavior and dentate gyrus synaptic plasticity in the Ts65Dn mouse model of Down syndrome.

Down syndrome (DS), trisomy 21, is caused by increased dose of genes present on human chromosome 21 (HSA21). The gene-dose hypothesis argues that a change in the dose of individual genes or regulatory sequences on HSA21 is necessary for creating DS-related phenotypes, including cognitive impairment. We focused on a possible role for Kcnj6, the gene encoding Kir3.2 (Girk2) subunits of a G-protein-coupled inwardly-rectifying potassium channel. This gene resides on a segment of mouse Chromosome 16 that is present in one extra copy in the genome of the Ts65Dn mouse, a well-studied genetic model of DS. Kir3.2 subunit-containing potassium channels serve as effectors for a number of postsynaptic metabotropic receptors including GABAB receptors. Several studies raise the possibility that increased Kcnj6 dose contributes to synaptic and cognitive abnormalities in DS. To assess directly a role for Kcnj6 gene dose in cognitive deficits in DS, we produced Ts65Dn mice that harbor only 2 copies of Kcnj6 (Ts65Dn:Kcnj6++- mice). The reduction in Kcnj6 gene dose restored to normal the hippocampal level of Kir3.2. Long-term memory, examined in the novel object recognition test with the retention period of 24h, was improved to the level observed in the normosomic littermate control mice (2N:Kcnj6++). Significantly, both short-term and long-term potentiation (STP and LTP) was improved to control levels in the dentate gyrus (DG) of the Ts65Dn:Kcnj6++- mouse. In view of the ability of fluoxetine to suppress Kir3.2 channels, we asked if fluoxetine-treated DG slices of Ts65Dn:Kcnj6+++ mice would rescue synaptic plasticity. Fluoxetine increased STP and LTP to control levels. These results are evidence that increased Kcnj6 gene dose is necessary for synaptic and cognitive dysfunction in the Ts65Dn mouse model of DS. Strategies aimed at pharmacologically reducing channel function should be explored for enhancing cognition in DS.

Genotype/phenotype correlation in a female patient with 21q22.3 and 12p13.33 duplications.

Many chromosomal rearrangements that lead to copy-number gains or losses have been shown to cause distinctive and recognizable clinical phenotypes. Conventional cytogenetic analysis can detect many, but not all, rearrangements depending on its power of resolution. The wide use of whole-genome array-based comparative genomic hybridization (array-CGH) techniques has allowed the detection of novel syndromes and to establish genotype-phenotype correlations by delineating at high resolution the regions involved in specific chromosomal aberrations. We report on a two and half-year-old female patient with intellectual disability and distinctive phenotypic features resulting from a de novo duplication of about 0.3 Mb in 21q22.3 associated with duplication of about 0.3 Mb in 12p13.33. The patient's chromosomal abnormalities were identified at the cytogenetic molecular level, using SNP array analysis, while GTG banding technique revealed a normal karyotype. Clinical findings of the patient were compared with Down syndrome and 12p duplication syndrome. This study suggests that an area of contiguous genes on the distal part of chromosome 21 (21q22.3) contribute to the Down syndrome phenotype and indicates that genes in the distal region of 12p (12p13.33) account for many facial characteristics and hypotonia of trisomy 12p syndrome.

Nuclear death receptor TRAIL-R2 inhibits maturation of let-7 and promotes proliferation of pancreatic and other tumor cells.

BACKGROUND & AIMS: Tumor necrosis factor-related apoptosis inducing ligand (TRAIL-R1) (TNFRSF10A) and TRAIL-R2 (TNFRSF10B) on the plasma membrane bind ligands that activate apoptotic and other signaling pathways. Cancer cells also might have TRAIL-R2 in the cytoplasm or nucleus, although little is known about its activities in these locations. We investigated the functions of nuclear TRAIL-R2 in cancer cell lines. METHODS: Proteins that interact with TRAIL-R2 initially were identified in pancreatic cancer cells by immunoprecipitation, mass spectrometry, and immunofluorescence analyses. Findings were validated in colon, renal, lung, and breast cancer cells. Functions of TRAIL-R2 were determined from small interfering RNA knockdown, real-time polymerase chain reaction, Drosha-activity, microRNA array, proliferation, differentiation, and immunoblot experiments. We assessed the effects of TRAIL-R2 overexpression or knockdown in human pancreatic ductal adenocarcinoma (PDAC) cells and their ability to form tumors in mice. We also analyzed levels of TRAIL-R2 in sections of PDACs and non-neoplastic peritumoral ducts from patients. RESULTS: TRAIL-R2 was found to interact with the core microprocessor components Drosha and DGCR8 and the associated regulatory proteins p68, hnRNPA1, NF45, and NF90 in nuclei of PDAC and other tumor cells. Knockdown of TRAIL-R2 increased Drosha-mediated processing of the let-7 microRNA precursor primary let-7 (resulting in increased levels of mature let-7), reduced levels of the let-7 targets (LIN28B and HMGA2), and inhibited cell proliferation. PDAC tissues from patients had higher levels of nuclear TRAIL-R2 than non-neoplastic pancreatic tissue, which correlated with increased nuclear levels of HMGA2 and poor outcomes. Knockdown of TRAIL-R2 in PDAC cells slowed their growth as orthotopic tumors in mice. Reduced nuclear levels of TRAIL-R2 in cultured pancreatic epithelial cells promoted their differentiation. CONCLUSIONS: Nuclear TRAIL-R2 inhibits maturation of the microRNA let-7 in pancreatic cancer cell lines and increases their proliferation. Pancreatic tumor samples have increased levels of nuclear TRAIL-R2, which correlate with poor outcome of patients. These findings indicate that in the nucleus, death receptors can function as tumor promoters and might be therapeutic targets.

Clinical comparison of 10q26 overlapping deletions: delineating the critical region for urogenital anomalies.

The 10q26 deletion syndrome is a clinically heterogeneous disorder. The most common phenotypic characteristics include pre- and/or postnatal growth retardation, microcephaly, developmental delay/intellectual disability and a facial appearance consisting of a broad nasal bridge with a prominent nose, low-set malformed ears, strabismus, and a thin vermilion of the upper lip. In addition, limb and cardiac anomalies as well as urogenital anomalies are occasionally observed. In this report, we describe three unrelated females with 10q26 terminal deletions who shared clinical features of the syndrome, including urogenital defects. Cytogenetic studies showed an apparently de novo isolated deletion of the long arm of chromosome 10, with breakpoints in 10q26.1, and subsequent oligo array-CGH analysis confirmed the terminal location and defined the size of the overlapping deletions as ∼ 13.46, ∼ 9.31 and ∼ 9.17 Mb. We compared the phenotypic characteristics of the present patients with others reported to have isolated deletions and we suggest that small 10q26.2 terminal deletions may be associated with growth retardation, developmental delay/intellectual disability, craniofacial features and external genital anomalies whereas longer terminal deletions affecting the 10q26.12 and/or 10q26.13 regions may be responsible for renal/urinary tract anomalies. We propose that the haploinsufficiency of one or several genes located in the 10q26.12-q26.13 region may contribute to the renal or urinary tract pathogenesis and we highlight the importance of FGFR2 and probably of CTBP2 as candidate genes.

10q26.1 Microdeletion: Redefining the critical regions for microcephaly and genital anomalies.

Distal 10q deletion syndrome is a well-characterized chromosomal disorder consisting of neurodevelopmental impairment, facial dysmorphism, cardiac malformations, genital and urinary tract defects, as well as digital anomalies. Patients with interstitial deletions involving band 10q26.1 present a phenotype similar to the ones with the distal 10q deletion syndrome, which led to the definition of a causal 600 kb smallest region of overlap (SRO). In this report, we describe a male patient with an interstitial 4.5 Mb deletion involving exclusively the 10q26.1 segment. He had growth and psychomotor retardation, microcephaly, flat feet, micropenis, and cryptorchidism. The patient's deleted region does not overlap the 10q SRO. We reviewed the clinical phenotype of patients with similar deletions and suggest the presence of two new SROs, one associated with microcephaly, growth and psychomotor retardation, and the other associated to genital anomalies. Interestingly, we narrowed those regions to segments encompassing five and two genes, respectively. FGFR2, NSMCE4A, and ATE1 were suggested as candidates for facial dysmorphism, growth cessation, and heart defects, respectively. WDR11 was linked to idiopathic hypogonadotropic hypogonadism and Kallmann syndrome. Its haploinsufficiency could play a crucial role in the genital anomalies of these patients.

Trim65: a cofactor for regulation of the microRNA pathway.

MicroRNA (miRNA) comprise a large family of non-protein coding transcripts which regulate gene expression in diverse biological pathways of both plants and animals. We recently used a systematic proteomic approach to generate a protein interactome map of the human miRNA pathway involved in miRNA biogenesis and processing. The interactome expands the number of candidate proteins in the miRNA pathway and connects the network to other cellular processes. Functional analyses identified TRIM65 and at least 3 other proteins as novel regulators of the miRNA pathway. Biochemical studies established that TRIM65 forms stable complexes with TNRC6 proteins and these molecules co-localize in P-body-like structures. Gain of function and RNAi analyses reveal that TRIM65 negatively regulates miRNA-driven suppression of mRNA translation by targeting TNRC6 proteins for ubiquitination and degradation. The potential molecular mechanisms which regulate TRIM65 catalytic activity are discussed.

C-terminal binding proteins are essential pro-survival factors that undergo caspase-dependent downregulation during neuronal apoptosis.

C-terminal binding proteins (CtBPs) are transcriptional co-repressors that are subject to proteasome-dependent downregulation during apoptosis. Alternative mechanisms that regulate CtBP expression are currently under investigation and the role of CtBPs in neuronal survival is largely unexplored. Here, we show that CtBPs are downregulated in cerebellar granule neurons (CGNs) induced to undergo apoptosis by a variety of stressors. Moreover, antisense-mediated downregulation of CtBP1 is sufficient to cause CGN apoptosis. Similarly, the CtBP inhibitor, 4-methylthio-2-oxobutyric acid, induces expression of the CtBP target Noxa and causes actinomycin-sensitive CGN apoptosis. Unexpectedly, we found that the mechanism of CtBP downregulation in CGNs undergoing apoptosis varies in a stimulus-specific manner involving either the proteasome or caspases. In the case of CGNs deprived of depolarizing potassium (5K apoptotic condition), caspases appear to play a dominant role in CtBP downregulation. However, incubation in 5K does not enhance the kinetics of CtBP1 degradation and recombinant CtBP1 is not cleaved in vitro by caspase-3. In addition, 5K has no significant effect on CtBP transcript expression. Finally, mouse embryonic stem cells display caspase-dependent downregulation of CtBP1 following exposure to staurosporine, an effect that is not observed in DGCR8 knockout cells which are deficient in miRNA processing. These data identify caspase-dependent downregulation of CtBPs as an alternative mechanism to the proteasome for regulation of these transcriptional co-repressors in neurons undergoing apoptosis. Moreover, caspases appear to regulate CtBP expression indirectly, at a post-transcriptional level, and via a mechanism that is dependent upon miRNA processing. We conclude that CtBPs are essential pro-survival proteins in neurons and their downregulation contributes significantly to neuronal apoptosis via the de-repression of pro-apoptotic genes.

Trisomy of the Dscr1 gene suppresses early progression of pancreatic intraepithelial neoplasia driven by oncogenic Kras.

Individuals with Down syndrome exhibit remarkably reduced incidence of most solid tumors including pancreatic cancer. Multiple mechanisms arising from the genetic complexity underlying Down syndrome has been suggested to contribute to such a broad cancer protection. In this study, utilizing a genetically engineered mouse model of pancreatic cancer, we demonstrate that trisomy of the Down syndrome critical region-1 (Dscr1), an endogenous calcineurin inhibitor localized on chromosome 21, suppresses the progression of pancreatic intraepithelial neoplasia-1A (PanIN-1A) to PanIN-1B lesions without affecting the initiation of PanIN lesions mediated by oncogenic Kras(G12D). In addition, we show that Dscr1 trisomy attenuates nuclear localization of nuclear factor of activated T-cells (NFAT) accompanied by upregulation of the p15(Ink4b) tumor suppressor and reduction of cell proliferation in early PanIN lesions. Our data suggest that attenuation of calcineurin-NFAT signaling in neoplastic pancreatic ductal epithelium by a single extra copy of Dscr1 is sufficient to inhibit the progression of early PanIN lesions driven by oncogenic Kras, and thus may be a potential mechanism underlying reduced incidence of pancreatic cancer in Down syndrome individuals.

3q29 microduplication syndrome: New evidence for the refinement of the critical region.

BACKGROUND: The 3q29 microduplication syndrome is a rare genomic disorder characterized by an extremely variable neurodevelopmental phenotype usually involving a genomic region ranging from 1.6 to 1.76 Mb. A small microduplication of 448.8 Kb containing only two genes was recently described in a patient with a 3q29 microduplication that was proposed as the minimal critical region of overlap of this syndrome. METHODS: Molecular karyotyping (array-CGH) was performed on DNA extracted from peripheral blood samples using Agilent-California USA Human Genome CGH Microarray 4 × 180 K. The proband and his younger brother were further tested with a next generation sequencing (NGS) panel including genes implicated in autism spectrum disorder and in neurodevelopmental disorders. Quantitative real-time PCR was applied to verify the abnormal array-CGH findings. RESULTS: Here, we report on a family with two males with neurodevelopmental disorders and an unaffected sibling with a small 3q29 microduplication (432.8 Kb) inherited from an unaffected mother that involves only two genes: DGL1 and BDH1. The proband had an additional intragenic duplication inherited from the unaffected father. Further testing was negative for Fragile X syndrome and for genes implicated in autism spectrum disorder and in neurodevelopmental disorders. CONCLUSION: To the best of our knowledge, one of the family members here analyzed is the second reported case of a patient carrying a small 3q29 microduplication including only DGL1 and BDH1 genes and without any additional genetic aberration. The recognition of the clinical spectrum in patients with the critical region of overlap associated with the 3q29 duplication syndrome should prove valuable for predicting outcomes and providing more informed genetic counseling to patients with duplications in this region.

Downregulation of the long noncoding RNA DSCR9 (Down syndrome critical region 9) delays breast cancer progression by modulating microRNA-504-5p-dependent G protein-coupled receptor 65.

Possible roles of long noncoding RNAs (lncRNAs) in cancer stem cells (CSCs) have often been reported. Here, we focused on the regulatory function of the lncRNA Down syndrome critical region 9 (DSCR9) in breast cancer stem cells (BCSCs). Through bioinformatics analysis, DSCR9, microRNA-504-5p (miR-504-5p), and G protein-coupled receptor 65 (GPR65) were identified as targets implicated in breast cancer development. Then, clinical tissue samples, breast cancer cells, and isolated BCSCs were used to determine the expression of DSCR9, miR-504-5p, and GPR65. The results confirmed the overexpression of DSCR9 and GPR65 but low expression of miR-504-5p in breast cancer tissues and cells as well as in BCSCs. Following mechanistic investigation, it was found that DSCR9 targeted miR-504-5p, and that silencing DSCR9 inhibited the proliferation of BCSCs by elevating the expression of miR-504-5p. Additionally, miR-504-5p targeted GPR65 and inhibited its expression. Moreover, GPR65 activated the MEK/ERK signaling pathway to regulate BCSC proliferation. Finally, animal study verified that depletion of DSCR9 inhibited the proliferation of BCSCs in vivo and that BCSC proliferation was restored by overexpression of GPR65. Altogether, our findings revealed that DSCR9 elevated GPR65 expression by targeting miR-504-5p to exacerbate breast cancer, highlighting a new treatment modality for breast cancer.