It is thought that small intestinal epithelia (IE) undergo continuous self-renewal primarily due to their population of undifferentiated stem cells. These stem cells give rise to transit amplifying (daughter/progenitor) cells, which can differentiate into all mature cell types required for normal gut function. Identification of stem cells in IE is paramount to fully understanding this renewal process. One major obstacle in gastrointestinal stem cell biology has been the lack of definitive markers that identify small intestinal stem cells (ISCs). Here we demonstrate that the novel putative ISC marker doublecortin and CaM kinase-like-1 (DCAMKL-1) is predominantly expressed in quiescent cells in the lower two-thirds of intestinal crypt epithelium and in occasional crypt-based columnar cells (CBCs). In contrast, the novel putative stem cell marker leucine-rich-repeat-containing G-protein-coupled receptor (LGR5) is observed in rapidly cycling CBCs and in occasional crypt epithelial cells. Furthermore, functionally quiescent DCAMKL-1+ crypt epithelial cells retain bromo-deoxyuridine in a modified label retention assay. Moreover, we demonstrate that DCAMKL-1 is a cell surface expressing protein; DCAMKL-1+ cells, isolated from the adult mouse small intestine by fluorescence activated cell sorting, self-renew and ultimately form spheroids in suspension culture. These spheroids formed glandular epithelial structures in the flanks of athymic nude mice, which expressed multiple markers of gut epithelial lineage. Thus, DCAMKL-1 is a marker of quiescent ISCs and can be distinguished from the cycling stem/progenitors (LGR51). Moreover, DCAMKL-1 can be used to isolate normal small intestinal stem cells and represents a novel research tool for regenerative medicine and cancer therapy.

PRMT5, which regulates gene expression by symmetric dimethylation of histones and non-histone target proteins, is overexpressed and plays a pathogenic role in many cancers. In diffuse large B cell lymphoma (DLBCL), the mechanisms of PRMT5 dysregulation and its role in lymphomagenesis remain largely unknown. Here we demonstrate that B cell receptor (BCR) signaling regulates PRMT5 expression in DLBCL cells. Immunohistochemical analysis reveals elevated levels of PRMT5 expression in DLBCL cases and in germinal center (GC) B cells when compared to naive B cells. PRMT5 can be induced in naive B cells by BCR stimulation. We discovered that BTK-NF-κB signaling induces PRMT5 transcription in activated B cell-like (ABC) DLBCL cells while BCR downstream PI3K-AKT-MYC signaling upregulates PRMT5 expression in both ABC and GCB DLBCL cells. PRMT5 inhibition inhibits the growth of DLBCL *

The ETS family of transcription factors is involved in several normal remodeling events and pathological processes including tumor progression. ETS transcription factors are divided into subfamilies based on the sequence and location of the ETS domain. ETV5 (Ets variant gene 5; also known as ERM) is a member of the PEA3 subfamily. Our meta-analysis of normal, benign, and malignant thyroid samples demonstrated that ETV5 expression is upregulated in papillary thyroid cancer and was predominantly associated with BRAF V600E or RAS mutations. However, the precise role of ETV5 in these lesions is unknown. In this study, we used the KTC1 cell line as a model for human advanced papillary thyroid cancer (PTC) because the cells harbor the heterozygous BRAF (V600E) mutation together with the C250T TERT promoter mutation. The role of ETV5 in PTC proliferation was tested using RNAi followed by high-throughput screening. Signaling pathways driving ETV5 expression were identified using specific pharmacological inhibitors. To determine if ETV5 influences the expression of epithelial-to-mesenchymal (EMT) markers in these cells, an EMT PCR array was used, and data were confirmed by qPCR and ChIP-qPCR. We found that ETV5 is critical for PTC cell growth, is expressed downstream of the MAPK pathway, and directly upregulates the transcription factor TWIST1, a known marker of intravasation and metastasis. Increased ETV5 expression could therefore be considered as a marker for advanced PTCs and a possible future therapeutic target.

Atherosclerosis rarely develops in the region of arteries exposed to undisturbed flow (u-flow, unidirectional flow). Instead, atherogenesis occurs in the area exposed to disturbed flow (d-flow, multidirectional flow). Based on these general pathohistological observations, u-flow is considered to be atheroprotective, while d-flow is atherogenic. The fact that u-flow and d-flow induce such clearly different biological responses in the wall of large arteries indicates that these two types of flow activate each distinct intracellular signaling cascade in vascular endothelial cells (ECs), which are directly exposed to blood flow. The ability of ECs to differentially respond to the two types of flow provides an opportunity to identify molecular events that lead to endothelial dysfunction and atherosclerosis. In this review, we will focus on various molecular events, which are differentially regulated by these two flow types. We will discuss how various kinases, ER stress, inflammasome, SUMOylation, and DNA methylation play roles in the differential flow response, endothelial dysfunction, and atherosclerosis. We will also discuss the interplay among the molecular events and how they coordinately regulate flow-dependent signaling and cellular responses. It is hoped that clear understanding of the way how the two flow types beget each unique phenotype in ECs will lead us to possible points of intervention against endothelial dysfunction and cardiovascular diseases.

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SUMOylation, a reversible post-transcriptional modification process, of proteins are involved in cellular differentiation, growth, and even motility by regulating various protein functions. SUMOylation is not limited to cytosolic proteins as recent evidence shows that nuclear proteins, those associated with membranes, and mitochondrial proteins are also SUMOylated. Moreover, it is now known that SUMOylation plays an important role in the process of major human ailments such as malignant, cardiovascular and neurological diseases. In this chapter, we will highlight and discuss how the localization of SUMO protease and SUMO E3 ligase in different compartments within a cell regulates biological processes that depend on SUMOylation. First, we will discuss the key role of SUMOylation in the nucleus, which leads to the development of endothelial dysfunction and atherosclerosis. We will then discuss how SUMOylation of plasma membrane potassium channel proteins are involved in epilepsy and arrhythmia. Mitochondrial proteins are known to be also SUMOylated, and the importance of dynamic-related protein 1 (DRP1) SUMOylation on mitochondrial function will be discussed. As we will emphasize throughout this review, SUMOylation plays crucial roles in different cellular compartments, which is coordinately regulated by the translocation of various SUMO proteases and SUMO E3 ligase. Comprehensive approach will be necessary to understand the molecular mechanism for efficiently moving around various enzymes that regulate SUMOylation within cells.

Early growth response gene (EGR1) is a transcription factor known to be a downstream effector of B-cell receptor signaling and Janus kinase 1 (JAK1) signaling in diffuse large B-cell lymphoma (DLBCL). While EGR1 is characterized as a tumor suppressor in leukemia and multiple myeloma, the role of EGR1 in lymphoma is unknown. Here we demonstrate that EGR1 is a potential oncogene that promotes cell proliferation in DLBCL. IHC analysis revealed that EGR1 expression is elevated in DLBCL compared with normal lymphoid tissues and the level of EGR1 expression is higher in activated B cell–like subtype (ABC) than germinal center B cell–like subtype (GCB). EGR1 expression is required for the survival and proliferation of DLBCL cells. Genomic analyses demonstrated that EGR1 upregulates expression of MYC and E2F pathway genes through the CBP/p300/H3K27ac/BRD4 axis while repressing expression of the type I IFN pathway genes by interaction with the corepressor NAB2. Genetic and pharmacologic inhibition of EGR1 synergizes with the BRD4 inhibitor JQ1 or the type I IFN inducer lenalidomide in growth inhibition of ABC DLBCL both in cell cultures and xenograft mouse models. Therefore, targeting oncogenic EGR1 signaling represents a potential new targeted therapeutic strategy in DLBCL, especially for the more aggressive ABC DLBCL. Implications: The study characterizes EGR1 as a potential oncogene that promotes cell proliferation and defines EGR1 as a new molecular target in DLBCL, the most common non-Hodgkin lymphoma.

Seed morphology in the subtribe Agrimoniinae (Rosaceae) was examined using scanning electron microscopy to identify distinct characters and evaluate their evolution in a phylogenetic framework for five genera in the subtribe: Agrimonia L., Aremonia Neck. ex Nestl., Hagenia J.F. Gmel., Leucosidea Eckl. & Zeyh., and Spenceria Trimen. All genera have one or two mature achenes in a fruiting hypanthium. In the seed coats, the cell shape, size, wall features, and sculpturing vary across genera. Of most significance is the presence of papillae structures in both Agrimonia and Aremonia. Through the mapping of papillae features onto phylogenetic trees, either one or two changes in seed coats are hypothesized. The phylogenetic tree inferred from four nuclear and six chloroplast regions of sequence data suggests that at least two steps of papillae sculpturing on seed coats are required. On the other hand, in the phylogenetic tree of a low-copy nuclear gene, one independent evolutionary step is postulated to explain the current character states. In the latter hypothesis, the seed coat sculpturing also supports a monophyletic relationship for cosmopolitan Agrimonia and European endemic Aremonia. The seed coat sculpturing provides valuable information for inferring phylogenetic relationships at the generic level in the subtribe Agrimoniinae.