Transcriptional regulators with broad expression in the zebrafish spinal cord.

BACKGROUND: The spinal cord is a crucial part of the vertebrate CNS, controlling movements and receiving and processing sensory information from the trunk and limbs. However, there is much we do not know about how this essential organ develops. Here, we describe expression of 21 transcription factors and one transcriptional regulator in zebrafish spinal cord. RESULTS: We analyzed the expression of aurkb, foxb1a, foxb1b, her8a, homeza, ivns1abpb, mybl2b, myt1a, nr2f1b, onecut1, sall1a, sall3a, sall3b, sall4, sox2, sox19b, sp8b, tsc22d1, wdhd1, zfhx3b, znf804a, and znf1032 in wild-type and MIB E3 ubiquitin protein ligase 1 zebrafish embryos. While all of these genes are broadly expressed in spinal cord, they have distinct expression patterns from one another. Some are predominantly expressed in progenitor domains, and others in subsets of post-mitotic cells. Given the conservation of spinal cord development, and the transcription factors and transcriptional regulators that orchestrate it, we expect that these genes will have similar spinal cord expression patterns in other vertebrates, including mammals and humans. CONCLUSIONS: Our data identify 22 different transcriptional regulators that are strong candidates for playing different roles in spinal cord development. For several of these genes, this is the first published description of their spinal cord expression.

A Human Hereditary Cardiomyopathy Shares a Genetic Substrate With Bicuspid Aortic Valve.

BACKGROUND: The complex genetics underlying human cardiac disease is evidenced by its heterogenous manifestation, multigenic basis, and sporadic occurrence. These features have hampered disease modeling and mechanistic understanding. Here, we show that 2 structural cardiac diseases, left ventricular noncompaction (LVNC) and bicuspid aortic valve, can be caused by a set of inherited heterozygous gene mutations affecting the NOTCH ligand regulator MIB1 (MINDBOMB1) and cosegregating genes. METHODS: We used CRISPR-Cas9 gene editing to generate mice harboring a nonsense or a missense MIB1 mutation that are both found in LVNC families. We also generated mice separately carrying these MIB1 mutations plus 5 additional cosegregating variants in the ASXL3, APCDD1, TMX3, CEP192, and BCL7A genes identified in these LVNC families by whole exome sequencing. Histological, developmental, and functional analyses of these mouse models were carried out by echocardiography and cardiac magnetic resonance imaging, together with gene expression profiling by RNA sequencing of both selected engineered mouse models and human induced pluripotent stem cell-derived cardiomyocytes. Potential biochemical interactions were assayed in vitro by coimmunoprecipitation and Western blot. RESULTS: Mice homozygous for the MIB1 nonsense mutation did not survive, and the mutation caused LVNC only in heteroallelic combination with a conditional allele inactivated in the myocardium. The heterozygous MIB1 missense allele leads to bicuspid aortic valve in a NOTCH-sensitized genetic background. These data suggest that development of LVNC is influenced by genetic modifiers present in affected families, whereas valve defects are highly sensitive to NOTCH haploinsufficiency. Whole exome sequencing of LVNC families revealed single-nucleotide gene variants of ASXL3, APCDD1, TMX3, CEP192, and BCL7A cosegregating with the MIB1 mutations and LVNC. In experiments with mice harboring the orthologous variants on the corresponding Mib1 backgrounds, triple heterozygous Mib1 Apcdd1 Asxl3 mice showed LVNC, whereas quadruple heterozygous Mib1 Cep192 Tmx3;Bcl7a mice developed bicuspid aortic valve and other valve-associated defects. Biochemical analysis suggested interactions between CEP192, BCL7A, and NOTCH. Gene expression profiling of mutant mouse hearts and human induced pluripotent stem cell-derived cardiomyocytes revealed increased cardiomyocyte proliferation and defective morphological and metabolic maturation. CONCLUSIONS: These findings reveal a shared genetic substrate underlying LVNC and bicuspid aortic valve in which MIB1-NOTCH variants plays a crucial role in heterozygous combination with cosegregating genetic modifiers.

Single versus multiple reoperations for recurrent intracranial meningiomas.

PURPOSE: To identify the risk factors and management of the multiple recurrences and reoperations for intracranial meningiomas. METHODS: Data of a neurosurgical series of 35 patients reoperated on for recurrent intracranial meningiomas were reviewed. Analyzed factors include patient age and sex, tumor location, extent of resection, WHO grade, Ki67-MIB1 and PR expression at initial diagnosis, time to recurrence; pattern of regrowth, extent of resection, WHO grade and Ki67-MIB1 at first recurrence were also analyzed. All these factors were stratified into two groups based on single (Group A) and multiple reoperations (Group B). RESULTS: Twenty-four patients (69%) belonged to group A and 11 (31%) to group B. The age < 65 years, male sex, incomplete resection at both initial surgery and first reoperation, and multicentric-diffuse pattern of regrowth at first recurrence are risk factors for multiple recurrences and reoperations. In group B, the WHO grade and Ki67-MIB1 increased in further recurrences in 54% and 64%, respectively. The time to recurrence was short in 7 cases (64%), whereas 4 patients (36%) further recurred after many years. Eight patients (73%) are still alive after 7 to 22 years and 2 to 4 reoperations. CONCLUSION: The extent of resection and the multicentric-diffuse pattern of regrowth at first recurrence are the main risk factors for multiple recurrences and reoperations. Repeated reoperations might be considered even in patients with extensive recurrent tumors before the anaplastic transformation occurs. In such cases, even partial tumor resections followed by radiation therapy may allow long survival in good clinical conditions.

Adenovirus entry: Stability, uncoating, and nuclear import.

Adenoviruses (AdVs) are widespread in vertebrates. They infect the respiratory and gastrointestinal tracts, the eyes, heart, liver, and kidney, and are lethal to immunosuppressed people. Mastadenoviruses infecting mammals comprise several hundred different types, and many specifically infect humans. Human adenoviruses are the most widely used vectors in clinical applications, including cancer treatment and COVID-19 vaccination. AdV vectors are physically and genetically stable and generally safe in humans. The particles have an icosahedral coat and a nucleoprotein core with a DNA genome. We describe the concept of AdV cell entry and highlight recent advances in cytoplasmic transport, uncoating, and nuclear import of the viral DNA. We highlight a recently discovered "linchpin" function of the virion protein V ensuring cytoplasmic particle stability, which is relaxed at the nuclear pore complex by cues from the E3 ubiquitin ligase Mind bomb 1 (MIB1) and the proteasome triggering disruption. Capsid disruption by kinesin motor proteins and microtubules exposes the linchpin and renders protein V a target for MIB1 ubiquitination, which dissociates V from viral DNA and enhances DNA nuclear import. These advances uncover mechanisms controlling capsid stability and premature uncoating and provide insight into nuclear transport of nucleic acids.

The E3 ubiquitin ligase MIB1 suppresses breast cancer cell migration through regulating CTNND1 protein level.

Breast cancer is one of the most common invasive cancers among women. The leading cause of difficulty in treating breast cancer patients is metastasis. Because cell migration is closely related to breast cancer metastasis, elucidating the detailed mechanism by which breast cancer cells promote their migration is crucial for improving the prognosis of patients. In this study, we investigated the relationship between breast cancer cell migration and Mind bomb1 (MIB1), an E3 ubiquitin ligase. We found that the downregulation of MIB1 promotes the cell migration of MCF7, a breast cancer-derived cell line. Furthermore, knockdown of MIB1 caused a reduction in CTNND1 and thereby impaired E-cadherin membrane localization in the cell boundary region. Taken together, our data suggest that MIB1 might play a role in suppressing breast cancer cell migration.

Low expression of Ki-67/MIB-1 labeling index in IDH wild type glioblastoma predicts prolonged survival independently by MGMT methylation status.

PURPOSE: The Ki-67/MIB-1 labeling index (LI) is clinically used to differentiate between high and low-grade gliomas, while its prognostic value remains questionable. Glioblastoma (GBM) expressing wild-type isocitrate dehydrogenase IDHwt, a relatively common malignant brain tumor in adults, is characterized by a dismal prognosis. Herein, we have retrospectively investigated the prognostic role of Ki-67/MIB-1-LI in a large group of IDHwt GBM. METHODS: One hundred nineteen IDHwt GBM patients treated with surgery followed by Stupp's protocol in our Institution between January 2016 and December 2021 were selected. A cut-off value for Ki-67/MIB-1-LI was used with minimal p-value based approach. RESULTS: A multivariate analysis showed that Ki-67/MIB-1-LI expression < 15% significantly correlated with a longer overall survival (OS), independently from the age of the patients, Karnofsky performance status scale, extent of surgery and O6-methylguanine (O6-MeG)-DNA methyltransferase promoter methylation status. CONCLUSIONS: Among other studies focused on Ki-67/MIB-1-LI, this is the first observational study showing a positive correlation between OS of IDHwt GBM patients and Ki-67/MIB-1-LI that we propose as a new predictive marker in this subtype of GBM.

NOTCH1 Gene as a Novel Cause of Thoracic Aortic Aneurysm in Patients with Tricuspid Aortic Valve: Two Cases Reported.

Thoracic aortic aneurysms (TAA) consist of abnormal dilation or the widening of a portion of the ascending aorta, due to weakness or destructuring of the walls of the vessel and are potentially lethal. The congenital bicuspid aortic valve (BAV) is considered a risk factor for the development of TAA because asymmetric blood flow through the bicuspid aortic valve detrimentally influences the wall of the ascending aorta. NOTCH1 mutations have been associated with non-syndromic TAAs as a consequence of BAV, but little is known regarding its haploinsufficiency and its relationship with connective tissue abnormalities. We report two cases in which there is clear evidence that alterations in the NOTCH1 gene are the cause of TAA in the absence of BAV. On the one hand, we describe a 117 Kb deletion that includes a large part of the NOTCH1 gene and no other coding genes, suggesting that haploinsufficiency can be considered a pathogenic mechanism for this gene associated with TAA. In addition, we describe two brothers who carry two variants, one in the NOTCH1 gene and another in the MIB1 gene, corroborating the involvement of different genes of the Notch pathway in aortic pathology.

Population-based estimate for the correlation of the Oncotype Dx Breast Recurrence Score® result and Ki-67 IHC MIB-1 pharmDx in HR+, HER2-, node-positive early breast cancer.

BACKGROUND: The United States Food and Drug Administration recently approved a Ki-67 immunohistochemistry (IHC) assay to identify patients with early breast cancer at high disease recurrence risk. The Oncotype Dx Breast Recurrence Score® assay has been validated in hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) invasive breast cancer (IBC) to predict chemotherapy benefit and distant recurrence risk, regardless of nodal status. This study assessed the correlation between Recurrence Score® (RS) results and the Ki-67 IHC MIB-1 pharmDx assay. METHODS: HR+, HER2-, N1 IBC samples with RS results were examined by Ki-67 IHC; 311 specimens were collected, including 275 without regard to RS ("unselected RS") and 36 more with RS 26-100; 12 were lymph node negative upon pathology report review, and one had no Ki-67 score, leaving 262 unselected RS and 298 total samples. Spearman rank correlation was calculated using the unselected samples and a weighted rank correlation using all samples. A receiver operating characteristic (ROC) curve for predicting high RS (26-100) from Ki-67 was constructed. RESULTS: The Spearman rank correlation between Ki-67 and RS results was moderately positive (unselected RS samples: 0.396; 95% confidence interval [CI] 0.288-0.493; all samples: 0.394; 95% CI 0.294-0.486). While 71% of samples with RS 26-100 had Ki-67 ≥ 20%, 75% with RS 0-25 had Ki-67 < 20%. ROC area under the curve was 0.792 (95% CI 0.725-0.859). CONCLUSIONS: The moderately positive correlation is consistent with previous analyses suggesting the Oncotype Dx® assay and Ki-67 IHC MIB-1 assay should not be used interchangeably in clinical practice.

A novel peptide encoded by N6-methyladenosine modified circMAP3K4 prevents apoptosis in hepatocellular carcinoma.

BACKGROUND: Circular RNAs (circRNAs) regulate various biological activities and have been shown to play crucial roles in hepatocellular carcinoma (HCC) progression. However, only a few coding circRNAs have been identified in cancers, and their roles in HCC remain elusive. This study aimed to identify coding circRNAs and explore their function in HCC. METHODS: CircMAP3K4 was selected from the CIRCpedia database. We performed a series of experiments to determine the characteristics and coding capacity of circMAP3K4. We then used in vivo and in vitro assays to investigate the biological function and mechanism of circMAP3K4 and its protein product, circMAP3K4-455aa, in HCC. RESULTS: We found circMAP3K4 to be an upregulated circRNA with coding potential in HCC. IGF2BP1 recognized the circMAP3K4 N6-methyladenosine modification and promoted its translation into circMAP3K4-455aa. Functionally, circMAP3K4-455aa prevented cisplatin-induced apoptosis in HCC cells by interacting with AIF, thus protecting AIF from cleavage and decreasing its nuclear distribution. Moreover, circMAP3K4-455aa was degraded through the ubiquitin-proteasome E3 ligase MIB1 pathway. Clinically, a high level of circMAP3K4 is an independent prognostic factor for adverse overall survival and adverse disease-free survival of HCC patients. CONCLUSIONS: CircMAP3K4 is a highly expressed circRNA in HCC. Driven by m6A modification, circMAP3K4 encoded circMAP3K4-455aa, protected HCC cells from cisplatin exposure, and predicted worse prognosis of HCC patients. Targeting circMAP3K4-455aa may provide a new therapeutic strategy for HCC patients, especially for those with chemoresistance. CircMAP3K4 is a highly expressed circRNA in HCC. Driven by m6A modification, IGF2BP1 facilitates circMAP3K4 peptide translation, then the circMAP3K4 peptide inhibits AIF cleavage and nuclear distribution, preventing HCC cells from cell death under stress and promoting HCC progression.

Acid ceramidase targeting pyruvate kinase affected trypsinogen activation in acute pancreatitis.

BACKGROUND: Acute pancreatitis is the sudden inflammation of the pancreas. Severe cases of acute pancreatitis are potentially fatal and have no specific treatment available. Premature trypsinogen activation could initiate acute pancreatitis. However, the mechanism underlying premature trypsinogen activation is not fully understood. METHODS: In this research, a primary pancreatic acinar cell or mouse acute pancreatitis model was constructed. The effect of acid ceramidase (ASAH1), which is responsible for sphingosine production, was investigated in trypsinogen activation in vitro and in vivo. Meanwhile, the proteins regulating ASAH1 or binding to sphingosine were also detected by co-immunoprecipitation followed by mass spectrometry. RESULTS: The results showed that ASAH1 increased in acute pancreatitis. Increased ASAH1 promoted the activation of trypsinogen and cathepsin B. On the contrary, ASAH1 downregulation inhibited trypsinogen and cathepsin B. Meanwhile, ASAH1 regulated the activity of trypsin and cathepsin B through sphingosine. Additionally, E3 ligase Mind bomb homolog 1 (MIB1) decreased in acute pancreatitis resulting in the decreased binding between MIB1 and ASAH1. Exogenous MIB1 diminished the elevation in trypsin activity induced by acute pancreatitis inducer. ASAH1 increased owing to the inhibition of the proteasome degradation by MIB1. In acute pancreatitis, sphingosine was found to bind to pyruvate kinase. Pyruvate kinase activation could reduce trypsinogen activation and mitochondrial reactive oxygen species (ROS) production induced by sphingosine. CONCLUSIONS: In conclusion, during the process of acute pancreatitis, MIB1 downregulation led to ASAH1 upregulation, resulting in pyruvate kinase inhibition, followed by trypsinogen activation.

Genome-wide association study revealed ABCD4 on SSC7 and GREB1L and MIB1 on SSC6 as crucial candidate genes for rib number in Beijing Black pigs.

As one of the few animals with variation in the number of rib pairs (RIB), the pig is a good model to study the mechanism of RIB regulation. Quantitative trait loci (QTL) for porcine RIB are present on Sus scrofa chromosome 7 (SSC7). Although several candidate genes exist in this QTL region on SSC7, the causal gene has yet to be verified. Beijing Black pig with 14-17 RIB is a good population for candidate gene mining and 1104 individuals were genotyped using the Illumina Porcine 50K BeadChip. A total of 14 SNPs from 95.49 to 97.78 Mb on SSC7 showed genome-wide significant association with RIB. On SSC7, a locuszoom plot using pairwise linkage disequilibrium displayed the narrowest linkage region encompassing only two genes, ABCD4 and VRTN. In mice, a transcriptome expression profile was obtained using three embryos at E9.5 (the critical period for rib formation). ABCD4 was highly expressed, but no expression of VRTN was detected. On SSC6, there were four genome-wide significant SNPs from 106.42 to 106.92 Mb associated with RIB. GREB1L and MIB1, in this region, were regarded as novel candidate genes. These results revealed a crucial candidate causal gene on SSC7 and novel genes on SSC6 for rib number and provided interesting new insights into its genetic basis.

Tumor doubling time as preoperative predictor of malignancy and recurrence in newly diagnosed meningioma.

Most meningiomas are benign, and the indications for surgery are determined by size and symptoms, but some are malignant and have a high recurrence rate. Currently, no preoperative prognostic factors have been established. The purpose of this study was to investigate whether tumor doubling time (Td) is useful in predicting tumor prognosis. Patients who underwent surgery for newly diagnosed meningioma at our hospital between 2007 and 2021 with preoperative magnetic resonance (MR) imaging evaluation over a period of 6 months were included in this study. We calculated the Td from the preoperative MR images and examined the correlation between Td and WHO grade, MIB-1 SI, and other conditions. A total of 269 newly diagnosed meningiomas were operated on during the study period, of which 62 met inclusion criteria. The median Td was 1082 days (54-8579 days), and MIB-1 SI was 2.45% (0.7-14.6%). Td and MIB-1 SI had a negative correlation (r = - 0.319, p = 0.0122). MIB-1 SI was higher in patients with Td < 3 years than in those with Td ≥ 3 (p = 0.005), and the incidence of high WHO grade (grade2) was higher in patients with Td < 1 year than in patients with Td ≥ 1 (p = 0.014). Meningiomas with Td < 3 years had significantly higher MIB-1 SI, and tumors with Td < 1 year had a higher likelihood of malignancy. Therefore, early treatment should be considered in patients with short Td meningioma even if asymptomatic, and further consideration could be given to radical resection at the time of surgery.

Notch signaling is a critical initiator of roof plate formation as revealed by the use of RNA profiling of the dorsal neural tube.

BACKGROUND: The dorsal domain of the neural tube is an excellent model to investigate the generation of complexity during embryonic development. It is a highly dynamic and multifaceted region being first transiently populated by prospective neural crest (NC) cells that sequentially emigrate to generate most of the peripheral nervous system. Subsequently, it becomes the definitive roof plate (RP) of the central nervous system. The RP, in turn, constitutes a patterning center for dorsal interneuron development. The factors underlying establishment of the definitive RP and its segregation from NC and dorsal interneurons are currently unknown. RESULTS: We performed a transcriptome analysis at trunk levels of quail embryos comparing the dorsal neural tube at premigratory NC and RP stages. This unraveled molecular heterogeneity between NC and RP stages, and within the RP itself. By implementing these genes, we asked whether Notch signaling is involved in RP development. First, we observed that Notch is active at the RP-interneuron interface. Furthermore, gain and loss of Notch function in quail and mouse embryos, respectively, revealed no effect on early NC behavior. Constitutive Notch activation caused a local downregulation of RP markers with a concomitant development of dI1 interneurons, as well as an ectopic upregulation of RP markers in the interneuron domain. Reciprocally, in mice lacking Notch activity, both the RP and dI1 interneurons failed to form and this was associated with expansion of the dI2 population. CONCLUSIONS: Collectively, our results offer a new resource for defining specific cell types, and provide evidence that Notch is required to establish the definitive RP, and to determine the choice between RP and interneuron fates, but not the segregation of RP from NC.

Increased proliferation is associated with CNS invasion in meningiomas.

INTRODUCTION: Meningiomas are the most common benign intracranial neoplasms. CNS invasion in meningiomas has been integrated into the 2016 WHO classification of CNS tumors as a stand-alone criterion for atypia. Since then, its prognostic impact has been debated based on contradictory results from retrospective analyses. The aim of the study was to elucidate whether histopathological evidence of CNS invasion is associated with increased proliferative potential. METHODS: We have conducted a quantified measurement of the proliferation marker Ki67 and analyzed its association with CNS invasion determined by histology together with other established prognostic markers of progression. Routine, immunohistochemical staining for Ki67 were digitalized and automatic quantification was done using Image J software. RESULTS: Overall, 1718 meningiomas were assessed. Histopathological CNS invasion was seen in 108 cases (6.7%). Uni- and multivariate analysis revealed a significantly higher Ki67 proliferation rate in meningiomas with CNS invasion (p < 0.0001 and p = 0.0098, respectively). CONCLUSIONS: Meningiomas with histopathological CNS invasion show a higher proliferative activity.

High Mib-1-score correlates with new cranial nerve deficits after surgery for frontal skull base meningioma.

Postoperative new cranial nerve deficits comprise severe concomitant morbidity in skull base meningioma surgery. Therefore, long-term cranial nerve integrity represents an important outcome measure. In the current study, we analyzed our institutional database in order to identify risk factors for postoperative new cranial nerve morbidity in the course of frontobasal meningioma surgery. Between 2009 and 2017, 195 patients were surgically treated for frontobasal meningioma at the authors' institution. Postoperative cranial nerve function was assessed immediately after surgery as well as 12 months postoperatively. A univariate and multivariate analysis was performed to identify factors influencing favorable postoperative cranial nerve outcome. Tumors with histological Mib-1-labeling indices > 5% were associated with a significantly higher percentage of new cranial nerve deficits immediately after surgery compared with those with Mib-1-labeling indices ≤ 5% (39% versus 20%, p = 0.029). Elevated Mib-1-labeling indices could be correlated with high CD68-positive macrophage staining (54% for Mib-1 index > 5% versus 19% for Mib-1 index ≤ 5%, p = 0.001). Elevated Mib-1-labeling index correlates with initial new cranial nerve dysfunction after resection of frontal skull base meningioma. With regard to elevated CD68-positive macrophage staining in high Mib-1-positive meningiomas, initial postoperative new cranial nerve morbidity might partly reflect macrophage-based inflammatory immune responses.

Cytoproliferative activity in colorectal poorly differentiated clusters: Biological significance in tumor setting.

BACKGROUND: Poorly differentiated clusters (PDCs) have gained a significant prognostic role in colorectal carcinomas (CRCs) being associated to high risk of lymph node metastasis, shorter survival time and poor prognosis. The knowledge in PDC biology is not completely clear. MATERIALS AND METHODS: We assessed Ki-67 LI in 45 CRCs showing ≥10 PDCs. We distinguished PDCs at the periphery of the tumor masses (pPDCs) from those within the tumor masses (cPDCs). We chose 3 cut-offs of Ki-67 labeling index (Ki-67 LI): <10%, 10-50%, and >50% of the labeled cells. RESULTS: Ki-67 LI in pPDCs was<10% in 37 cases (82%), 10-50% in 6 cases (13%) and >50%in 2 cases (5%); Ki-67 LI in cPDCs was<10% in 4 cases (23.5%), 10-50% in 4 (23.5%) and >50% in 9 (54%). Ki-67 LI in tumor budding foci (TBs) was <10% in 8 cases (32%), 10-50% in 8 (32%) and >50% in 9 (36%). The difference of Ki-67 LI reaches the statistical significance (p < 0.005). Ki-67 LI <10% in the pPDCs was associated with nodal metastases (pN+) (p < 0.0001), pTNM stage III and IV(p < 0.0001) and TB (p < 0.001). Ki-67 LI > 50% in cPDC was significantly associated withpT3-pT4 and advanced pTNM stages (p < 0.0001), N+ (p = 0.0001) and LVI (p < 0.05). CONCLUSION: Different Ki-67 LI detected between cPDCs and pPDCs suggesting a biological difference in PDCs. An actively proliferating central tumor areas can be distinguished from the peripheral portion of the tumors in which the cells interact with the stroma acquiring invasive and metastatic potential.

Zika virus increases mind bomb 1 levels, causing degradation of pericentriolar material 1 (PCM1) and dispersion of PCM1-containing granules from the centrosome.

The centrosome is a cytoplasmic nonenveloped organelle functioning as one of the microtubule-organizing centers and composing a centriole center surrounded by pericentriolar material (PCM) granules. PCM consists of many centrosomal proteins, including PCM1 and centrosomal protein 131 (CEP131), and helps maintain centrosome stability. Zika virus (ZIKV) is a flavivirus of the family Flaviviridae whose RNA and viral particles are replicated in the cytoplasm. However, how ZIKV interacts with host cell components during its productive infection stage is incompletely understood. Here, using several primate cell lines, we report that ZIKV infection disrupts and disperses the PCM granules. We demonstrate that PCM1- and CEP131-containing granules are dispersed in ZIKV-infected cells, whereas the centrioles remain intact. We found that ZIKV does not significantly alter cellular skeletal proteins, and, hence, these proteins may not be involved in the interaction between ZIKV and centrosomal proteins. Moreover, ZIKV infection decreased PCM1 and CEP131 protein, but not mRNA, levels. We further found that the protease inhibitor MG132 prevents the decrease in PCM1 and CEP131 levels and centriolar satellite dispersion. Therefore, we hypothesized that ZIKV infection induces proteasomal PCM1 and CEP131 degradation and thereby disrupts the PCM granules. Supporting this hypothesis, we show that ZIKV infection increases levels of mind bomb 1 (MIB1), previously demonstrated to be an E3 ubiquitin ligase for PCM1 and CEP131 and that ZIKV fails to degrade or disperse PCM in MIB1-ko cells. Our results imply that ZIKV infection activates MIB1-mediated ubiquitination that degrades PCM1 and CEP131, leading to PCM granule dispersion.

A Nucleolar Protein, Nepro, Is Essential for the Maintenance of Early Neural Stem Cells and Preimplantation Embryos.

Notch signaling is required for maintaining neural stem cells (NSCs) in the developing brain. NSCs have potential to give rise to many neuronal types in the early telencephalon, and the potential decreases as embryonic development proceeds. Nepro, which encodes a unique nucleolar protein and is activated downstream of Notch, is essential for maintaining NSCs in the early telencephalon. Nepro is also expressed at basal levels and required for maintaining the preimplantation embryo, by repressing mitochondria-associated p53 apoptotic signaling. Notch signaling also controls dendritic complexity in mitral cells, major projection neurons in the olfactory bulb, showing that many steps of neural development involve Notch signaling.

Mib1 contributes to persistent directional cell migration by regulating the Ctnnd1-Rac1 pathway.

Persistent directional cell migration is involved in animal development and diseases. The small GTPase Rac1 is involved in F-actin and focal adhesion dynamics. Local Rac1 activity is required for persistent directional migration, whereas global, hyperactivated Rac1 enhances random cell migration. Therefore, precise control of Rac1 activity is important for proper directional cell migration. However, the molecular mechanism underlying the regulation of Rac1 activity in persistent directional cell migration is not fully understood. Here, we show that the ubiquitin ligase mind bomb 1 (Mib1) is involved in persistent directional cell migration. We found that knockdown of MIB1 led to an increase in random cell migration in HeLa cells in a wound-closure assay. Furthermore, we explored novel Mib1 substrates for cell migration and found that Mib1 ubiquitinates Ctnnd1. Mib1-mediated ubiquitination of Ctnnd1 K547 attenuated Rac1 activation in cultured cells. In addition, we found that posterior lateral line primordium cells in the zebrafish mib1ta52b mutant showed increased random migration and loss of directional F-actin-based protrusion formation. Knockdown of Ctnnd1 partially rescued posterior lateral line primordium cell migration defects in the mib1ta52b mutant. Taken together, our data suggest that Mib1 plays an important role in cell migration and that persistent directional cell migration is regulated, at least in part, by the Mib1-Ctnnd1-Rac1 pathway.

The impact of the MIB-1 index on facial nerve outcomes in vestibular schwannoma surgery.

BACKGROUND: Facial nerve palsy is a severe morbid condition that occurs after vestibular schwannoma (VS) surgery. The objective of this study was to evaluate facial nerve outcomes based on surgical techniques, tumour size, and immunohistochemical factors. METHODS: One hundred eighteen patients with VS were retrospectively analysed. Gross total resection (GTR) was achieved in 83 patients, and subtotal resection (STR) was achieved in 35 patients. Follow-up was 60 months (median). Facial nerve outcomes were assessed for 24 months after surgery. Analysis of the MIB-1 index was performed in 114 patients (97%) to evaluate recurrence and facial nerve outcomes. RESULTS: Immediately after surgery, 16 of 35 patients (45.7%) with STR and 21 of 83 patients (25.3%) with GTR had a good (House-Brackmann (HB) score ≤ 2) facial nerve outcome (p = 0.029). Semi-sitting positioning (p = 0.002) and tumour size class of 3 (> 4 cm) were also associated with worse HB outcomes after 2 years (p = 0.004) in univariate analyses. The MIB-1 index was significantly correlated with diffuse infiltration of tumour-associated CD45+ lymphocytes (r = 0.63, p = 0.015) and CD68+ macrophages (r = 0.43, p = 0.021). ROC analysis found an AUC of 0.73 (95% CI = 0.60-0.86, p = 0.003) for the MIB-1 index in predicting poor facial nerve outcomes. Binary logistic regression analysis revealed an MIB-1 index ≥ 5% (16/28 (57.1%) vs. 5/40 (12.5%); p < 0.001, OR = 14.0, 95% CI = 3.2-61.1) and a tumour size class of 3 (6/8 (75.0%) vs. 2/8 (25.0%); p = 0.01, OR = 14.56, 95% CI = 1.9-113.4) were predictors of poor HB scores (≥ 3) after 1 year. CONCLUSIONS: An MIB-1 index ≥ 5% seems to predict worse long-term facial nerve outcomes in VS surgery.