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The Effects of Regulator of G-Protein Signaling 2 (RGS2) on Depression-Like Behavior in Female California Mice
No full textSuperior efficacy of co-targeting GFI1/KDM1A and BRD4 against AML and post-MPN secondary AML cells.
Get PDFThere is an unmet need to overcome nongenetic therapy-resistance to improve outcomes in AML, especially post-myeloproliferative neoplasm (MPN) secondary (s) AML. Studies presented describe effects of genetic knockout, degradation or small molecule targeted-inhibition of GFI1/LSD1 on active enhancers, altering gene-expressions and inducing differentiation and lethality in AML and (MPN) sAML cells. A protein domain-focused CRISPR screen in LSD1 (KDM1A) inhibitor (i) treated AML cells, identified BRD4, MOZ, HDAC3 and DOT1L among the codependencies. Our findings demonstrate that co-targeting LSD1 and one of these co-dependencies exerted synergistic in vitro lethality in AML and post-MPN sAML cells. Co-treatment with LSD1i and the JAKi ruxolitinib was also synergistically lethal against post-MPN sAML cells. LSD1i pre-treatment induced GFI1, PU.1 and CEBPα but depleted c-Myc, overcoming nongenetic resistance to ruxolitinib, or to BETi in post-MPN sAML cells. Co-treatment with LSD1i and BETi or ruxolitinib exerted superior in vivo efficacy against post-MPN sAML cells. These findings highlight LSD1i-based combinations that merit testing for clinical efficacy, especially to overcome nongenetic therapy-resistance in AML and post-MPN sAML
Extracellular vesicles produced by primary human keratinocytes in response to TLR agonists induce stimulus-specific responses in antigen-presenting cells.
No full textCells can communicate through the extracellular vesicles (EVs) they secrete. Pathogen associated molecular patterns (PAMPs), alter the biophysical and communicative properties of EVs released from cells, but the functional consequences of these changes are unknown. Characterization of keratinocyte-derived EVs after poly(I:C) treatment (poly(I:C)-EVs) showed slight differences in levels of EV markers TSG101 and Alix, a loss of CD63 and were positive for autophagosome marker LC3b-II and the cytokine IL36γ compared to EVs from unstimulated keratinocytes (control-EVs). Flagellin treatment (flagellin-EVs) led to an EV marker profile like control-EVs but lacked LC3b-II. Flagellin-EVs also lacked IL-36γ despite nearly identical intracellular levels. While poly(I:C) treatment led to the clear emergence of a > 200 nm diameter EV sub-population, these were not found in flagellin-EVs. EV associated IL-36γ colocalized with LC3b-II in density gradient analysis, equilibrating to 1.10 g/mL, indicating a common EV species. Poly(I:C), but not flagellin, induced intracellular vesicles positive for IL-36γ, LC3b-II, Alix and TSG101, consistent with fusion of autophagosomes and multivesicular bodies. Simultaneous rapamycin and flagellin treatment induced similar intracellular vesicles but was insufficient for the release of IL-36γ+/LC3b-II+ EVs. Finally, a qRT-PCR array screen showed eight cytokine/chemokine transcripts were altered (p < 0.05) in monocyte-derived Langerhans cells (LCs) when stimulated with poly(I:C)-EVs while three were altered when LCs were stimulated with flagellin-EVs compared to control-EVs. After independent confirmation, poly(I:C)-EVs upregulated BMP6 (p = 0.035) and flagellin-EVs upregulated CXCL8 (p = 0.005), VEGFA (p = 0.018) and PTGS2 (p = 0.020) compared to control-EVs. We conclude that exogenous signals derived from pathogens can alter keratinocyte-mediated modulation of the local immune responses by inducing changes in the types of EVs secreted and responses in antigen presenting cells
EXPLORING THE RACIAL DISPARITIES OF COLON CANCER OUTCOMES IN THE SETTING OF OBESITY
No full textBackground: African Americans (AA) have higher incidence and mortality from colon cancer
compared to Caucasian Americans (CA). The mechanisms that drive this difference are not
well understood. Genetic, environmental and socioeconomic factors play important roles in
colon cancer pathogenesis and each may contribute to this disparity. One of the important
factors that may influence different aspects of colon cancer is obesity. Obesity as a lowgrade
inflammatory state creates changes in the epigenetic and metabolic landscape in
ways that promote the initiation and progression of colon cancer. In this study, we use a
multipronged approach in exploring potential contributory elements that may explain the
disproportionate burden of colon cancer in AA patients. Methods: IRB-approved prospective
collection of samples from colon cancer patients undergoing surgical resection from the two
cohorts (AA/CA, Normal/Obese) were assembled and clinically annotated. The samples
included tumor and adjacent non-tumor tissues and blood for plasma isolation (AA=30,
CA=23). Tumor tissue DNA was isolated and mutation analysis was acquired via PanelSeq,
which included 60 commonly mutated genes in colon cancer. Plasma samples will be sent for metabolomic analysis. The tumor tissue samples were used for stem cell isolation and
were cultured as 3-dimensional organoid cultures. Finally, tumor organoids will be transplanted
into NOD scid gamma mice using colonoscopy-assisted orthotopic xenotransplantation
method that we developed. Results: DNA mutation analysis showed widely different
mutational landscape across the samples (Figure 1). Notable mutations included common
colon cancer drivers such as APC and KRAS, as well as mismatch repair mutations such as
MLH1 and PMS1. AA and CA colon tumor organoids exhibited no significant differences
in proliferation (Figure 2). Metabolomics analysis and orthotopic transplantation to be
performed. Conclusions: Colon cancer is the third leading cause of cancer death in the
U.S. The incidence and mortality are worse in AA patients compared to CA patients. Moreover,
obesity is a major modifiable risk factor that plays an important role in the pathogenesis of
colon cancer. Here we show that the mutational landscape of colon cancer is distinct between
the two cohorts (AA vs. CA) and BMIs (Normal vs. Obese). The metabolomics data is
pending but we expect to see differences. Finally, we developed in vitro colon tumor organoid
cultures derived from AA patient samples that can be utilized for mechanistic experiments.
Tumor organoids will also be used for orthotopic xenotransplantation in our model for
colon cancer. To our knowledge, this has never been done with samples from AA patients
and opens the door for future work in exploring the pathogenesis of the heightened colon
cancer incidence and mortality in this underrepresented population
The right dose: molecular compensation maintains rRNA homeostasis upon reduction of ribosomal gene dosage in Arabidopsis
No full textThe structure of ORC–Cdc6 on an origin DNA reveals the mechanism of ORC activation by the replication initiator Cdc6
Get PDFThe Origin Recognition Complex (ORC) binds to sites in chromosomes to specify the location of origins of DNA replication. The S. cerevisiae ORC binds to specific DNA sequences throughout the cell cycle but becomes active only when it binds to the replication initiator Cdc6. It has been unclear at the molecular level how Cdc6 activates ORC, converting it to an active recruiter of the Mcm2-7 hexamer, the core of the replicative helicase. Here we report the cryo-EM structure at 3.3 Å resolution of the yeast ORC–Cdc6 bound to an 85-bp ARS1 origin DNA. The structure reveals that Cdc6 contributes to origin DNA recognition via its winged helix domain (WHD) and its initiator-specific motif. Cdc6 binding rearranges a short α-helix in the Orc1 AAA+ domain and the Orc2 WHD, leading to the activation of the Cdc6 ATPase and the formation of the three sites for the recruitment of Mcm2-7, none of which are present in ORC alone. The results illuminate the molecular mechanism of a critical biochemical step in the licensing of eukaryotic replication origins
Early-life exposure to environmental contaminants perturbs the sperm epigenome and induces negative pregnancy outcomes for three generations via the paternal lineage
Get PDFDue to the grasshopper effect, the Arctic food chain in Canada is contaminated with persistent organic pollutants (POPs) of industrial origin, including polychlorinated biphenyls and organochlorine pesticides. Exposure to POPs may be a contributor to the greater incidence of poor fetal growth, placental abnormalities, stillbirths, congenital defects and shortened lifespan in the Inuit population compared to non-Aboriginal Canadians. Although maternal exposure to POPs is well established to harm pregnancy outcomes, paternal transmission of the effects of POPs is a possibility that has not been well investigated. We used a rat model to test the hypothesis that exposure to POPs during gestation and suckling leads to developmental defects that are transmitted to subsequent generations via the male lineage. Indeed, developmental exposure to an environmentally relevant Arctic POPs mixture impaired sperm quality and pregnancy outcomes across two subsequent, unexposed generations and altered sperm DNA methylation, some of which are also observed for two additional generations. Genes corresponding to the altered sperm methylome correspond to health problems encountered in the Inuit population. These findings demonstrate that the paternal methylome is sensitive to the environment and that some perturbations persist for at least two subsequent generations. In conclusion, although many factors influence health, paternal exposure to contaminants plays a heretofore-underappreciated role with sperm DNA methylation contributing to the molecular underpinnings involved
The chicken pan-genome reveals gene content variation and a promoter region deletion in IGF2BP1 affecting body size.
Get PDFDomestication and breeding have reshaped the genomic architecture of chicken, but the retention and loss of genomic elements during these evolutionary processes remain unclear. We present the first chicken pan-genome constructed using 664 individuals, which identified an additional ∼66.5 Mb sequences that are absent from the reference genome (GRCg6a). The constructed pan-genome encoded 20,491 predicated protein-coding genes, of which higher expression level are observed in conserved genes relative to dispensable genes. Presence/absence variation (PAV) analyses demonstrated that gene PAV in chicken was shaped by selection, genetic drift, and hybridization. PAV-based GWAS identified numerous candidate mutations related to growth, carcass composition, meat quality, or physiological traits. Among them, a deletion in the promoter region of IGF2BP1 affecting chicken body size is reported, which is supported by functional studies and extra samples. This is the first time to report the causal variant of chicken body size QTL located at chromosome 27 which was repeatedly reported. Therefore, the chicken pan-genome is a useful resource for biological discovery and breeding. It improves our understanding of chicken genome diversity and provides materials to unveil the evolution history of chicken domestication
From human to mouse and back offers hope for patients with fibromyalgia
No full textFibromyalgia syndrome (FMS) is a highly prevalent, debilitating disease with heterogeneous symptoms of widespread pain and tenderness, fatigue, sleep disturbance, and impaired cognition. The cause of FMS is unknown, but the clinical constellation of symptoms and abnormalities in the neuroendocrine system, autonomic nervous system, and sleep implicate the nervous system in its pathogenesis. In this issue of the JCI, Goebel, Krock, et al. identified antibodies from patients with FMS that produce FMS in mice by binding to satellite glial cells (SGCs), which envelope sensory neurons. Because antibodies harvested from patients with FMS, but not controls, stimulated SGCs to an activated state known to mediate chronic pain by augmenting neuronal activity, these findings reveal a pivotal role for autoreactive IgG in the pathophysiology of FMS. These important findings pave a pathway to study mechanism-based experimental therapeutics targeting IgG titers or antibody binding to SGCs underlying the neuroimmune dysfunction of FMS
Butyrophilin-like 2 regulates site-specific adaptations of intestinal γδ intraepithelial lymphocytes
Get PDFTissue-resident γδ intraepithelial lymphocytes (IELs) orchestrate innate and adaptive immune responses to maintain intestinal epithelial barrier integrity. Epithelia-specific butyrophilin-like (Btnl) molecules induce perinatal development of distinct Vγ TCR+ IELs, however, the mechanisms that control γδ IEL maintenance within discrete intestinal segments are unclear. Here, we show that Btnl2 suppressed homeostatic proliferation of γδ IELs preferentially in the ileum. High throughput transcriptomic characterization of site-specific Btnl2-KO γδ IELs reveals that Btnl2 regulated the antimicrobial response module of ileal γδ IELs. Btnl2 deficiency shapes the TCR specificities and TCRγ/δ repertoire diversity of ileal γδ IELs. During DSS-induced colitis, Btnl2-KO mice exhibit increased inflammation and delayed mucosal repair in the colon. Collectively, these data suggest that Btnl2 fine-tunes γδ IEL frequencies and TCR specificities in response to site-specific homeostatic and inflammatory cues. Hence, Btnl-mediated targeting of γδ IEL development and maintenance may help dissect their immunological functions in intestinal diseases with segment-specific manifestations