Hearing preservation outcomes using direct cranial nerve eight and auditory brainstem response neuromonitoring in the resection of vestibular schwannomas.

OBJECTIVE: Advancements in microsurgical technique and technology continue to improve outcomes in patients with skull base tumor. The primary cranial nerve eight monitoring systems used in hearing preservation surgery for vestibular schwannomas (VSs) are direct cranial nerve eight monitoring (DCNEM) and auditory brainstem response (ABR), although current guidelines are unable to definitively recommend one over the other due to limited literature on the topic. Thus, further research is needed to determine the utility of DCNEM and ABR. The authors performed a retrospective cohort study and created an interactive model that compares hearing preservation outcomes based on tumor size in patients receiving ABR+DCNEM and ABR-only monitoring. METHODS: Twenty-eight patients received ABR+DCNEM and 72 patients received ABR-only monitoring during VS hearing preservation surgery at a single tertiary academic medical center between January 2008 and November 2022. Inclusion criteria consisted of adult patients with a preoperative American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) hearing classification of A or B. Tumor size was measured as the maximal medial to lateral length, including the internal auditory canal component. RESULTS: Overall hearing preservation (word recognition score [WRS] > 0%) was achieved in 31 patients with ABR-only monitoring (43.1%) and in 18 patients with ABR+DCNEM (64.3%). Serviceable hearing preservation (AAO-HNS class A or B) was attained in 19 patients with ABR-only monitoring (26.4%) and in 11 patients with ABR+DCNEM (39.3%). There was no difference in overall hearing preservation between the two groups (p = 0.13). Change in tumor size was not associated with the odds of serviceable hearing preservation for the ABR-only group (p = 0.89); however, for ABR+DCNEM, there was some indication of an interaction between tumor size and the association of ABR+DCNEM versus ABR-only monitoring, with the odds of serviceable hearing preservation at p = 0.089. Furthermore, with ABR+DCNEM, every 0.5-cm increase in tumor size was associated with a decreased odds of serviceable hearing preservation on multivariable analysis (p = 0.05). For both overall and serviceable hearing preservation, a worse preoperative AAO-HNS classification was associated with a decreased odds of preservation (OR 0.43, 95% CI 0.19-0.97, p = 0.042; OR 0.17, 95% CI 0.053-0.55, p = 0.0031, respectively). CONCLUSIONS: The result of this interactive model study proposes that there may be a higher chance of hearing preservation when using ABR+DCNEM rather than ABR alone for smaller tumors, with that relationship reversing as tumor size increases.

The Wnt-dependent master regulator NKX1-2 controls mouse pre-implantation development.

Embryo size, specification, and homeostasis are regulated by a complex gene regulatory and signaling network. Here we used gene expression signatures of Wnt-activated mouse embryonic stem cell (mESC) clones to reverse engineer an mESC regulatory network. We identify NKX1-2 as a novel master regulator of preimplantation embryo development. We find that Nkx1-2 inhibition reduces nascent RNA synthesis, downregulates genes controlling ribosome biogenesis, RNA translation, and transport, and induces severe alteration of nucleolus structure, resulting in the exclusion of RNA polymerase I from nucleoli. In turn, NKX1-2 loss of function leads to chromosome missegregation in the 2- to 4-cell embryo stages, severe decrease in blastomere numbers, alterations of tight junctions (TJs), and impairment of microlumen coarsening. Overall, these changes impair the blastocoel expansion-collapse cycle and embryo cavitation, leading to altered lineage specification and developmental arrest.

The Master Regulator Protein BAZ2B Can Reprogram Human Hematopoietic Lineage-Committed Progenitors into a Multipotent State.

Bi-species, fusion-mediated, somatic cell reprogramming allows precise, organism-specific tracking of unknown lineage drivers. The fusion of Tcf7l1-/- murine embryonic stem cells with EBV-transformed human B cell lymphocytes, leads to the generation of bi-species heterokaryons. Human mRNA transcript profiling at multiple time points permits the tracking of the reprogramming of B cell nuclei to a multipotent state. Interrogation of a human B cell regulatory network with gene expression signatures identifies 8 candidate master regulator proteins. Of these 8 candidates, ectopic expression of BAZ2B, from the bromodomain family, efficiently reprograms hematopoietic committed progenitors into a multipotent state and significantly enhances their long-term clonogenicity, stemness, and engraftment in immunocompromised mice. Unbiased systems biology approaches let us identify the early driving events of human B cell reprogramming.

ZCCHC17 is a master regulator of synaptic gene expression in Alzheimer's disease.

Motivation: In an effort to better understand the molecular drivers of synaptic and neurophysiologic dysfunction in Alzheimer's disease (AD), we analyzed neuronal gene expression data from human AD brain tissue to identify master regulators of synaptic gene expression. Results: Master regulator analysis identifies ZCCHC17 as normally supporting the expression of a network of synaptic genes, and predicts that ZCCHC17 dysfunction in AD leads to lower expression of these genes. We demonstrate that ZCCHC17 is normally expressed in neurons and is reduced early in the course of AD pathology. We show that ZCCHC17 loss in rat neurons leads to lower expression of the majority of the predicted synaptic targets and that ZCCHC17 drives the expression of a similar gene network in humans and rats. These findings support a conserved function for ZCCHC17 between species and identify ZCCHC17 loss as an important early driver of lower synaptic gene expression in AD. Availability and implementation: Matlab and R scripts used in this paper are available at https://github.com/afteich/AD_ZCC. Contact: aft25@cumc.columbia.edu. Supplementary information: Supplementary data are available at Bioinformatics online.

Identification of neurodegenerative factors using translatome-regulatory network analysis.

For degenerative disorders of the CNS, the main obstacle to therapeutic advancement has been the challenge of identifying the key molecular mechanisms underlying neuronal loss. We developed a combinatorial approach including translational profiling and brain regulatory network analysis to search for key determinants of neuronal survival or death. Following the generation of transgenic mice for cell type-specific profiling of midbrain dopaminergic neurons, we established and compared translatome libraries reflecting the molecular signature of these cells at baseline or under degenerative stress. Analysis of these libraries by interrogating a context-specific brain regulatory network led to the identification of a repertoire of intrinsic upstream regulators that drive the dopaminergic stress response. The altered activity of these regulators was not associated with changes in their expression levels. This strategy can be generalized for the identification of molecular determinants involved in the degeneration of other classes of neurons.

Cytosolic pressure provides a propulsive force comparable to actin polymerization during lamellipod protrusion.

Does cytosolic pressure facilitate f-actin polymerization to push the leading edge of a cell forward during self-propelled motion? AFM force-distance (f-d) curves obtained from lamellipodia of live cells often exhibit a signal from which the tension, bending modulus, elastic modulus and thickness in the membrane-cortex complex can be estimated close to the contact point. These measurements permit an estimate of the cytosolic pressure via the canonical Laplace force balance. The deeper portion of the f-d curve allows estimation of the bulk modulus of the cytoskeleton after removal of the bottom effect artifact. These estimates of tension, pressure, cortex thickness and elastic moduli imply that cytosolic pressure both pushes the membrane forward and compresses the actin cortex rearward to facilitate f-actin polymerization. We also estimate that cytosolic pressure fluctuations, most likely induced by myosin, provide a propulsive force comparable to that provided by f-actin polymerization in a lamellipod.

Identifying candidate drivers of alcohol dependence-induced excessive drinking by assembly and interrogation of brain-specific regulatory networks.

BACKGROUND: A systems biology approach based on the assembly and interrogation of gene regulatory networks, or interactomes, was used to study neuroadaptation processes associated with the transition to alcohol dependence at the molecular level. RESULTS: Using a rat model of dependent and non-dependent alcohol self-administration, we reverse engineered a global transcriptional regulatory network during protracted abstinence, a period when relapse rates are highest. We then interrogated the network to identify master regulator genes that mechanistically regulate brain region-specific signatures associated with dependent and non-dependent alcohol self-administration. Among these, the gene coding for the glucocorticoid receptor was independently identified as a master regulator in multiple brain regions, including the medial prefrontal cortex, nucleus accumbens, central nucleus of the amygdala, and ventral tegmental area, consistent with the view that brain reward and stress systems are dysregulated during protracted abstinence. Administration of the glucocorticoid antagonist mifepristone in either the nucleus accumbens or ventral tegmental area selectively decreased dependent, excessive, alcohol self-administration in rats but had no effect on non-dependent, moderate, alcohol self-administration. CONCLUSIONS: Our study suggests that assembly and analysis of regulatory networks is an effective strategy for the identification of key regulators of long-term neuroplastic changes within specific brain regions that play a functional role in alcohol dependence. More specifically, our results support a key role for regulatory networks downstream of the glucocorticoid receptor in excessive alcohol drinking during protracted alcohol abstinence.

Assembly and interrogation of Alzheimer's disease genetic networks reveal novel regulators of progression.

Alzheimer's disease (AD) is a complex multifactorial disorder with poorly characterized pathogenesis. Our understanding of this disease would thus benefit from an approach that addresses this complexity by elucidating the regulatory networks that are dysregulated in the neural compartment of AD patients, across distinct brain regions. Here, we use a Systems Biology (SB) approach, which has been highly successful in the dissection of cancer related phenotypes, to reverse engineer the transcriptional regulation layer of human neuronal cells and interrogate it to infer candidate Master Regulators (MRs) responsible for disease progression. Analysis of gene expression profiles from laser-captured neurons from AD and controls subjects, using the Algorithm for the Reconstruction of Accurate Cellular Networks (ARACNe), yielded an interactome consisting of 488,353 transcription-factor/target interactions. Interrogation of this interactome, using the Master Regulator INference algorithm (MARINa), identified an unbiased set of candidate MRs causally responsible for regulating the transcriptional signature of AD progression. Experimental assays in autopsy-derived human brain tissue showed that three of the top candidate MRs (YY1, p300 and ZMYM3) are indeed biochemically and histopathologically dysregulated in AD brains compared to controls. Our results additionally implicate p53 and loss of acetylation homeostasis in the neurodegenerative process. This study suggests that an integrative, SB approach can be applied to AD and other neurodegenerative diseases, and provide significant novel insight on the disease progression.

A systems approach to drug discovery in Alzheimer's disease.

In the articles included in this volume, one feels a strong frustration among the writers with the slow course of therapeutics development for Alzheimer's disease and with the clinical failure of targeted therapeutic agents despite substantial progress in our understanding of the biology and biochemistry of the disease.

Spinning disk confocal imaging of neutrophil migration in zebrafish.

Live-cell imaging techniques have been substantially improved due to advances in confocal microscopy instrumentation coupled with ultrasensitive detectors. The spinning disk confocal system is capable of generating images of fluorescent live samples with broad dynamic range and high temporal and spatial resolution. The ability to acquire fluorescent images of living cells in vivo on a millisecond timescale allows the dissection of biological processes that have not previously been visualized in a physiologically relevant context. In vivo imaging of rapidly moving cells such as neutrophils can be technically challenging. In this chapter, we describe the practical aspects of imaging neutrophils in zebrafish embryos using spinning disk confocal microscopy. Similar setups can also be applied to image other motile cell types and signaling processes in translucent animals or tissues.

Parents' dental anxiety and oral health literacy: effects on parents' and children's oral health-related experiences.

OBJECTIVE: To explore a) the relationship between parents'/guardians' dental anxiety and oral health literacy and b) those between these variables and background and oral health-related characteristics. METHODS: Survey data were collected from 187 parents/guardians (81% female; average age 37 years). Dental anxiety was measured with the Dental Anxiety Scale - Revised (DAS-R) and oral health literacy with the Rapid Estimate of Adult Literacy in Dentistry (REALD-30). Children's dental charts were reviewed to collect information about their dental treatment. RESULTS: DAS-R and REALD-30 scores were correlated (r = -0.22; P = 0.003). A multivariate regression model with DAS-R score as the dependent variable showed that the DAS-R score has a significant multivariate association with REALD-30, oral health, income, and presence of fillings. CONCLUSIONS: Dental anxiety and oral health literacy are related. However, DAS score has a significant multivariate association with the four variables REALD-30 score, oral health, income, and presence of fillings. These findings show that among socioeconomically disadvantaged patients, the contributors to poor oral health are interrelated and multidetermined and include poor oral health literacy and dental anxiety. The public health message is that in order to improve the overall oral health of socioeconomically disadvantaged patients, public health stakeholders need to consider how to communicate with these patients effectively and how to reduce dental anxiety. Gaining a better understanding of how to communicate with parents a) at an appropriate literacy level and b) in a way that it reduces dental anxiety is therefore crucial.

Hypothalamic proteoglycan syndecan-3 is a novel cocaine addiction resilience factor.

Proteoglycans like syndecan-3 have complex signaling roles in addition to their function as structural components of the extracellular matrix. Here, we show that syndecan-3 in the lateral hypothalamus has an unexpected new role in limiting compulsive cocaine intake. In particular, we observe that syndecan-3 null mice self-administer greater amounts of cocaine than wild-type mice. This effect can be rescued by re-expression of syndecan-3 in the lateral hypothalamus with an adeno-associated viral vector. Adeno-associated viral vector delivery of syndecan-3 to the lateral hypothalamus also reduces motivation for cocaine in normal mice. Syndecan-3 limits cocaine intake by modulating the effects of glial-cell-line-derived neurotrophic factor, which uses syndecan-3 as an alternative receptor. Our findings indicate syndecan-3-dependent signaling as a novel therapeutic target for the treatment of cocaine addiction.

Choline intake exceeding current dietary recommendations preserves markers of cellular methylation in a genetic subgroup of folate-compromised men.

Severe choline deficiency adversely affects cellular methylation and DNA integrity, with potentially serious implications for disease risk. As part of a 12-wk controlled choline intervention study conducted in folate-compromised Mexican-American men (n = 60; 18-55 y) differing in the methylenetetrahydrofolate reductase (MTHFR) C677T genotype (21 677CC, 29 677TT), this study evaluated the effects of varied choline intakes (300, 550, 1100, and 2200 mg/d) on the change (i.e. wk 12-0) in markers of cellular methylation and DNA integrity. Choline intake affected the change in plasma S-adenosylmethionine (P = 0.044), with decreases tending to be greater (P < or = 0.08) in the 300 and 550 mg/d groups than in the 2200 mg/d group. Choline intake also interacted with the MTHFR C677T genotype to affect the change in genomic DNA methylation and DNA damage. In men with the MTHFR 677CC genotype, choline intake affected (P = 0.007) the change in DNA methylation, with a greater decrease (P < 0.02) in the 300 mg/d group than in the 1100 and 2200 mg/d groups. In men with the MTHFR 677CC genotype, choline intake also affected (P = 0.047) the change in DNA damage, with the increase tending to be greater (P = 0.07) in the 550 mg/d group than in the 2200 mg/d group. Choline intake did not affect these variables in men with the MTHFR 677TT genotype. Overall, these data suggest that choline intake exceeding current dietary recommendations preserves markers of cellular methylation and attenuates DNA damage in a genetic subgroup of folate-compromised men.

A UV-responsive internal ribosome entry site enhances serine hydroxymethyltransferase 1 expression for DNA damage repair.

Thymidine nucleotides are required for faithful DNA synthesis and repair, and their de novo biosynthesis is regulated by serine hydroxymethyltransferase 1 (SHMT1). The SHMT1 transcript contains a heavy chain ferritin, heterogeneous nuclear ribonucleoprotein H2, and CUG-binding protein 1-responsive internal ribosome entry site (IRES) that regulates SHMT1 translation. In this study a non-lethal dose of UVC is shown to increase SHMT1 IRES activity and protein levels in four different cell lines. The mechanism for the UV-induced activation of the SHMT1 IRES involves an increase in heavy chain ferritin and heterogeneous nuclear ribonucleoprotein H2 expression and the translocation of CUG-binding protein 1 from the nucleus to the cytoplasm. The UV-induced increase in SHMT1 translation is accompanied by an increase in the small ubiquitin-like modifier-dependent nuclear localization of the de novo thymidylate biosynthesis pathway and a decrease in DNA strand breaks, indicating a role for SHMT1 and nuclear folate metabolism in DNA repair.

Animal models for the molecular and mechanistic study of lymphatic biology and disease.

The development of animal model systems for the study of the lymphatic system has resulted in an explosion of information regarding the mechanisms governing lymphatic development and the diseases associated with lymphatic dysfunction. Animal studies have led to a new molecular model of embryonic lymphatic vascular development, and have provided insight into the pathophysiology of both inherited and acquired lymphatic insufficiency. It has become apparent, however, that the importance of the lymphatic system to human disease extends, beyond its role in lymphedema, to many other diverse pathologic processes, including, very notably, inflammation and tumor lymphangiogenesis. Here, we have undertaken a systematic review of the models as they relate to molecular and functional characterization of the development, maturation, genetics, heritable and acquired diseases, and neoplastic implications of the lymphatic system. The translation of these advances into therapies for human diseases associated with lymphatic dysfunction will require the continued study of the lymphatic system through robust animal disease models that simulate their human counterparts.

All three LDL receptor homology regions of the LDL receptor-related protein bind multiple ligands.

The three complete human LDL receptor homology regions of the LDL receptor-related protein (sLRP2, sLRP3, and sLRP4) have been expressed in Pichia pastoris SMD1168 with constitutive coexpression of the receptor-associated protein (RAP). Each sLRP was purified to homogeneity after deglycosylation using a combination of anion-exchange and size exclusion chromatography. Mass spectrometry and N-terminal sequencing confirmed the identity of each fragment at purified yields of several milligrams per liter. Despite the large number of disulfide linkages and glycosylation sites in each LDL receptor homology region (sLRP), all were shown to be competent for binding to several LRP1 ligands. Each sLRP also bound human RAP, which is thought to be a generalized receptor antagonist, in solution-binding experiments. As expected, sLRP2 bound the receptor-binding domain of alpha(2)-macroglobulin (residues 1304-1451). All three sLRPs bound human apolipoprotein-enriched beta very low density lipoprotein, the canonical ligand for this receptor. All three sLRPs also bound lactoferrin and thrombin-protease nexin 1 complexes. Only sLRP4 bound thrombin-antithrombin III complexes. The results show that binding-competent LDL receptor homology regions (sLRPs) can be produced in high yield in P. pastoris and readily purified. Each sLRP has binding sites for multiple ligands, but not all ligand binding could be competed by RAP.

The third circulation: radionuclide lymphoscintigraphy in the evaluation of lymphedema.

Lymphedema-edema that results from chronic lymphatic insufficiency-is a chronic debilitating disease that is frequently misdiagnosed, treated too late, or not treated at all. There are, however, effective therapies for lymphedema that can be implemented, particularly after the disorder is properly diagnosed and characterized with lymphoscintigraphy. On the basis of the lymphoscintigraphic image pattern, it is often possible to determine whether the limb swelling is due to lymphedema and, if so, whether compression garments, massage, or surgery is indicated. Effective use of lymphoscintigraphy to plan therapy requires an understanding of the pathophysiology of lymphedema and the influence of technical factors such as selection of the radiopharmaceutical, imaging times after injection, and patient activity after injection on the images. In addition to reviewing the anatomy and physiology of the lymphatic system, we review physiologic principles of lymphatic imaging with lymphoscintigraphy, discuss different qualitative and quantitative lymphoscintigraphic techniques and their clinical applications, and present clinical cases depicting typical lymphoscintigraphic findings.

Animal models for the study of lymphatic insufficiency.

Lymphedema is the term commonly employed to describe the spectrum of pathological states that arise as a consequence of functional lymphatic insufficiency. These human disease entities currently lack an effective cure. Satisfactory therapeutic strategies for both primary and secondary lymphedema will require additional insight into the complex cellular mechanisms and responses that comprise both normal lymphatic function and its regional derangement in states of pathologic dysfunction. Such insights must, initially, be derived from suitable animal models of the chronic human disease process. Historically, efforts to replicate the untreated disease of human lymphedema in animals, through surgery, irradiation, and toxicology, have been fraught with difficulty. The major impediments to the creation of satisfactory animal models have included an inability to reproduce the chronic disease in a stable, reproducible format. Recently, with the promise of potentially successful growth factor-mediated therapeutic lymphangiogenesis, and with the enhanced availability of investigative tools to assess therapeutic responses to molecular therapies, there has been a resurgence of interest in the development of viable animal models of lymphatic insufficiency. Current research has led to the development of genetic and postsurgical models of lymphedema that closely simulate the human conditions of primary and secondary lymphatic insufficiency, respectively. Such models will help to refine the assessment of various therapeutic approaches and their potential applicability to human disease interventions.

Therapeutic lymphangiogenesis with human recombinant VEGF-C.

Chronic regional impairments of the lymphatic circulation often lead to striking architectural abnormalities in the lymphedematous tissues. Lymphedema is a common, disabling disease that currently lacks a cure. Vascular endothelial growth factors C and D mediate lymphangiogenesis through the VEGFR-3 receptor on lymphatic endothelia. The purpose of this study was to investigate the therapeutic potential for lymphangiogenesis with VEGF-C. We developed a rabbit ear model to simulate human chronic postsurgical lymphatic insufficiency. Successful, sustained surgical ablation of the ear lymphatics was confirmed by water displacement volumetry. After complete healing, the experimental animals (n=8) received a single, s.c. 100 microg dose of VEGF-C in the operated ear; controls (n=8) received normal saline. Radionuclide lymphoscintigraphy was performed to quantitate lymphatic function. Immunohistochemistry (IHC) was performed 7-8 days following treatment. After VEGF-C, there was a quantifiable amelioration of lymphatic function. IHC confirmed a significant increase in lymphatic vascularity, along with reversal of the intense tissue hypercellularity of untreated lymphedema. This study confirms the capacity of a single dose of VEGF-C to induce therapeutic lymphangiogenesis in acquired lymphedema. In addition to improving lymphatic function and vascularity, VEGF-C can apparently reverse the abnormalities in tissue architecture that accompany chronic lymphatic insufficiency.

The role of chemokines in human cardiovascular pathology: enhanced biological insights.

A growing body of experimental evidence supports the pivotal role of chemokines in the pathogenesis of vascular disease. The endothelial expression of monocyte chemoattractant protein-1 (MCP-1) is apparently essential for the earliest cellular responses of atherogenesis. Many atherogenic and anti-atherogenic stimuli can be construed to exert their effects predominantly upon MCP-1 expression within the vascular wall. The atherogenic effects of interleukin-8 (IL-8) seem to be mediated through the down-regulation of the tissue inhibitor of metalloproteinase-1 (TIMP-1). Biological expression of these two important vascular chemokines is further modulated by NF-kappaB. The delineation of these molecular forces that drive atherogenesis increasingly underscores the pivotal role of various chemokines. It is anticipated that more precise delineation of these patterns of gene expression will help to identify molecular targets for the prevention and treatment of atherosclerosis.