Faculty Bibliography

BACKGROUND:Atrioventricular valve development relies upon the precisely defined dimensions of the atrioventricular canal (AVC). Current models suggest that Wnt signaling plays an important role atop a pathway that promotes AVC development. The factors that confine AVC differentiation to the appropriate location, however, are less well understood. RESULTS:Transmembrane protein 2 (Tmem2) is a key player in restricting AVC differentiation: in zebrafish, tmem2 mutants display an expansion of AVC characteristics, but the molecular mechanism of Tmem2 function in this context remains unclear. Through structure-function analysis, we demonstrate that the extracellular portion of Tmem2 is crucial for its role in restricting AVC boundaries. Importantly, the Tmem2 ectodomain contains regions implicated in the depolymerization of hyaluronic acid (HA). We find that tmem2 mutant hearts exhibit excess HA deposition alongside broadened distribution of Wnt signaling. Moreover, addition of ectopic hyaluronidase can restore the restriction of AVC differentiation in tmem2 mutants. Finally, we show that alteration of a residue important for HA depolymerization impairs the efficacy of Tmem2 function during AVC development. CONCLUSIONS:Taken together, our data support a model in which HA degradation, regulated by Tmem2, limits the distribution of Wnt signaling and thereby confines the differentiation of the AVC.

Stem cell systems regulate tissue development and maintenance. The germline stem cell system is essential for animal reproduction, controlling both the timing and number of progeny through its influence on gamete production. In this review, we first draw general comparisons to stem cell systems in other organisms, and then present our current understanding of the germline stem cell system in Caenorhabditis elegans In contrast to stereotypic somatic development and cell number stasis of adult somatic cells in C. elegans, the germline stem cell system has a variable division pattern, and the system differs between larval development, early adult peak reproduction and age-related decline. We discuss the cell and developmental biology of the stem cell system and the Notch regulated genetic network that controls the key decision between the stem cell fate and meiotic development, as it occurs under optimal laboratory conditions in adult and larval stages. We then discuss alterations of the stem cell system in response to environmental perturbations and aging. A recurring distinction is between processes that control stem cell fate and those that control cell cycle regulation. C. elegans is a powerful model for understanding germline stem cells and stem cell biology.

Identification of biomarkers is a major goal of personalized medicine. Large transcriptome screens have identified new targets and molecular signatures for disease sub-types. However, tissue spatial information, which fundamentally alters in vivo cell behavior and gene expression, is lost. To understand spatial context and validate bulk tissue screens, most researchers rely exclusively on antibodies and immunostaining assays. Unfortunately, this is either not the appropriate choice for some targets, such as long non-coding RNAs, or it is not feasible because no reliable antibodies exist. To address these issues, we have established an alternative work-flow incorporating RNA in situ hybridization (CISH and FISH), whole slide and/or multispectral scanning and image analysis. Methods: RNAscope technology; Leica SCN scanner or Vectra3 multispectral imaging system for image acquisition; ImageJ2/FIJI, R, InForm and Visiopharm software platforms for quantitative analysis. Results: Several laboratories have used this workflow to address their specific questions. For example, we established and validated RNAscope assays for signaling factor transcripts, which are now integrated into an ongoing clinical trial. In this case, all tested commercial antibodies failed the validation assay. We also assessed expression of LNC RNAs in prostate cancer and put in place protocols for normalizing probe quantification across samples. The analysis revealed that storage and/or sample preparation affected the detection of certain LNC RNAs more than others identifying important factors regarding banking specimens. Spatial heat map visualization of RNAscope probes revealed an unexpected distribution of inflammatory cytokine targets in the kidney which are now being further investigated. In conclusion, RNA ISH is a powerful alternative strategy for assessing the spatial distribution of specific cell populations and critical biomarkers within intact tissues. This approach coupled with sophisticated imaging modalities and downstream analysis support provides new collaborative opportunities for Core laboratories.

The most frequently mutated oncogene in cancer is KRAS, which uses alternative fourth exons to generate two gene products (KRAS4A and KRAS4B) that differ only in their C-terminal membrane-targeting region¹. Because oncogenic mutations occur in exons 2 or 3, two constitutively active KRAS proteins-each capable of transforming cells-are encoded when KRAS is activated by mutation². No functional distinctions among the splice variants have so far been established. Oncogenic KRAS alters the metabolism of tumour cells³ in several ways, including increased glucose uptake and glycolysis even in the presence of abundant oxygen⁴ (the Warburg effect). Whereas these metabolic effects of oncogenic KRAS have been explained by transcriptional upregulation of glucose transporters and glycolytic enzymes^3-5, it is not known whether there is direct regulation of metabolic enzymes. Here we report a direct, GTP-dependent interaction between KRAS4A and hexokinase 1 (HK1) that alters the activity of the kinase, and thereby establish that HK1 is an effector of KRAS4A. This interaction is unique to KRAS4A because the palmitoylation-depalmitoylation cycle of this RAS isoform enables colocalization with HK1 on the outer mitochondrial membrane. The expression of KRAS4A in cancer may drive unique metabolic vulnerabilities that can be exploited therapeutically.

Social skills intervention is an evidence-based practice for enhancing communication and interpersonal skills in individuals with autism spectrum disorder (ASD). Participation in the Program for the Education and Enrichment of Relational Skills (PEERS®), a manualized social skills intervention for adolescents with ASD, is associated with improved social skills and peer interactions, as well as decreased autism symptoms. Participation in PEERS® has also been linked to increased parent self-efficacy and decreased family chaos. The present study examined parenting stress in the context of PEERS®. Following participation in PEERS®, parents reported lower levels of parenting stress associated with adolescent mood and social isolation. These findings provide further evidence of the family-wide benefits of adolescent-focused social skills intervention.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is one of the most common causes of sudden cardiac death in young people. Patients diagnosed with ARVC may experience increased likelihood of development of anxiety and depression, emphasizing the need for accurate diagnosis. To assist future genetic diagnosis and avoidance of misdiagnosis, we evaluated the reported monogenic disease-causing variants in ARVD/C Genetic Variants Database, Human Gene Mutation Database, and ClinVar. Within the aforementioned databases, 630 monogenic disease-causing variants from 18 genes were identified. In the genome Aggregation Database, 226 of these were identified; 68 of which were found at greater than expected prevalence. Furthermore, 37/226 genetic variants were identified amongst the 409 000 UK biobank participants, 23 were not associated with ARVC. Among the 14 remaining variants, 13 were previously found with greater than expected prevalence for a monogenic variant. Nevertheless, they were associated with serious cardiac phenotypes, suggesting that these 13 variants may be disease-modifiers of ARVC, rather than monogenic disease-causing. In summary, more than 10% of variants previously reported to cause ARVC were found unlikely to be associated with highly penetrant monogenic forms of ARVC. Notably, all variants in OBSCN and MYBPC3 were found, making these unlikely to be monogenic causes of ARVC. This article is protected by copyright. All rights reserved.

Several modalities of multiplex immunofluorescence histology currently available require significant time and resources to implement. Many research laboratories develop questions benefiting from multiplex staining and analysis but do not have the human resources and/or equipment to perform the assay. Furthermore, pilot studies use similar metrics to evaluate multiplex histology data making them ideal for a core laboratory setup. The objective of this study was to establish a semi-automated workflow for multiplex immunofluorescence staining and initial quantification of cell populations in whole slide microscopy scans. The requirements for the workflow included: A. minimal transfer of decision making from the researcher to core personnel (Semi-Automation), B. modifiable in terms of antigen targets and tissue types with minimal disruption to the process and C. reproducible across samples submitted at different time periods (eg patient samples).

INTRODUCTION/BACKGROUND:Epigenetic information such as DNA methylation is a useful biomarker that reflects complex gene-environmental interaction. Peripheral tissues such as blood and saliva are commonly collected as the source of genomic DNA in cohort studies. Epigenetic studies mainly use blood, while a few studies have addressed the epigenetic characteristics of saliva. METHODS:The effects of methods for DNA extraction and purification from saliva on DNA methylation were surveyed using Illumina Infinium HumanMethylation450 BeadChip. Using 386 661 probes, DNA methylation differences between blood and saliva from 22 healthy volunteers, and their functional and structural characteristics were examined. CpG sites with DNA methylation levels showing large interindividual variations in blood were evaluated using saliva DNA methylation profiles. RESULTS:Genomic DNA prepared by simplified protocol from saliva showed a similar quality DNA methylation profile to that derived from the manufacturer provided protocol. Consistent with previous studies, the DNA methylation profiles of blood and saliva showed high correlations. Blood showed 1,514 hypomethylated and 2099 hypermethylated probes, suggesting source-dependent DNA methylation patterns. CpG sites with large methylation difference between the two sources were underrepresented in the promoter regions and enriched within gene bodies. CpG sites with large interindividual methylation variations in blood also showed considerable variations in saliva. CONCLUSION/CONCLUSIONS:In addition to high correlation in DNA methylation profiles, CpG sites showing large interindividual DNA methylation differences were similar between blood and saliva, ensuring saliva could be a suitable alternative source for genomic DNA in cohort studies. Consideration of source-dependent DNA methylation differences will, however, be necessary.

The embryonic tissue origins of the skull vault result in difference in the properties of the bone component. However, the specific molecular differences behind the bone elements are not clear. In this study, we analyzed the differences in osteoblast activities from frontal and parietal bone at embryonic stage. The results showed that the osteoblasts of neural crest derived frontal bone are more capable of less bone matrix, higher proliferative ability and robust ALP activities, while the osteoblasts of mesoderm derived parietal tissue are with higher bone matrix, poor ALP activities and less ability of ossification. Our data provides a specific molecular difference in osteoblasts of frontal and parietal bone during the development.
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PURPOSE/OBJECTIVE:Spinal cord injury (SCI) often results in significant and catastrophic dysfunction and disability and imposes a huge economic burden on society. This study aimed to determine whether progranulin (PGRN) plays a role in the progressive damage following SCI and evaluate the potential for development of a PGRN derivative as a new therapeutic target in SCI. METHODS:) and wild-type (WT) littermate mice were subjected to SCI using a weight-drop technique. Local PGRN expression following injury was evaluated by Western blotting and immunofluorescence. Basso Mouse Scale (BMS), inclined grid walking test, and inclined plane test were conducted at indicated time points to assess neurological recovery. Inflammation and apoptosis were examined by histology (Hematoxylin and Eosin (H&E) staining and Nissl staining, TUNEL assays, and immunofluorescence), Western blotting (from whole tissue protein for iNOS/p-p65/Bax/Bcl-2), and ex vivo ELISA (for TNFα/IL-1β/IL-6/IL-10). To identify the prophylactic and therapeutic potential of targeting PGRN, a PGRN derived small protein, Atsttrin, was conjugated to PLGA-PEG-PLGA thermosensitive hydrogel and injected into intrathecal space prior to SCI. BMS was recorded for neurological recovery and Western blotting was applied to detect the inflammatory and apoptotic proteins. RESULTS:mice manifested uncontrolled and expanded inflammation and apoptosis. Administration of control-released Atsttrin could improve the neurological recovery and the pro-inflammatory/pro-apoptotic effect of PGRN deficiency. CONCLUSION/CONCLUSIONS:PGRN deficiency exacerbates SCI by promoting neuroinflammation and cellular apoptosis, which can be alleviated by Atsttrin. Collectively, our data provide novel evidence of using PGRN derivatives as a promising therapeutic approach to improve the functional recovery for patients with spinal cord injury.