Associations with symbionts within the gut lumen of hosts are particularly prone to disruption due to the constant influx of ingested food and non-symbiotic microbes, yet we know little about how ...partner fidelity is maintained. Here we describe for the first time the existence of a gut morphological filter capable of protecting an animal gut microbiome from disruption. The proventriculus, a valve located between the crop and midgut of insects, functions as a micro-pore filter in the Sonoran Desert turtle ant (Cephalotes rohweri), blocking the entry of bacteria and particles ⩾0.2 μm into the midgut and hindgut while allowing passage of dissolved nutrients. Initial establishment of symbiotic gut bacteria occurs within the first few hours after pupation via oral-rectal trophallaxis, before the proventricular filter develops. Cephalotes ants are remarkable for having maintained a consistent core gut microbiome over evolutionary time and this partner fidelity is likely enabled by the proventricular filtering mechanism. In addition, the structure and function of the cephalotine proventriculus offers a new perspective on organismal resistance to pathogenic microbes, structuring of gut microbial communities, and development and maintenance of host-microbe fidelity both during the animal life cycle and over evolutionary time.
Full text
Available for:
NUK, SBMB, SBNM, UL, UM, UPUK
This study demonstrates that innervation dependent on two different neurotrophin tyrosine kinase (trk) receptors can form the same types of sensory endings (Merkel endings) in the same target (Merkel ...cells of vibrissa follicles). Some endings transiently express trkA during their initial development, whereas others express trkC throughout their development. Consequently, elimination of kinase domains of either trkA or trkC each result in a partial loss of Merkel endings, whereas absence of kinase domains of both receptors results in a total loss. At the onset of Merkel ending development, at least one kinase-lacking trkC isoform is transiently expressed on all the follicle cells, while neurotrophin 3 is transiently expressed only in the cells at the middle third of the follicle where the Merkel endings and cells develop. This transient non-neuronal expression of truncated trkC is essential for development of any Merkel endings, whereas some Merkel endings and cells still begin to develop in the absence of neurotrophin 3. Therefore, truncated trkC plays a more important role in the development of this innervation than kinase forms of trkA or trkC or of NT3, the only known ligand for trkC receptors.
The dental pulp is a favorable model for studies of interactions between nociceptive sensory neurons and their peripheral target tissues. In the present study, we retrogradely labeled pulpal afferent ...neurons with an improved method that permits monitoring of changes in neuronal phenotype in response to controlled tooth injuries. The capacity of retrograde neuronal tracers to diffuse through dentinal tubules was exploited, thereby avoiding the severe injury to the pulp associated with previous tracer application methods. The strategy was to apply the durable fluorescent tracer, Fluoro-gold (FG), to exposed dentin in the floor of shallow cavities in molars, in order to pre-label pulpal neurons in trigeminal ganglia of young adult Sprague–Dawley rats. A high percentage of pupal afferent neurons were retrogradely labeled by application of FG to exposed dentin and the FG fluorescent signal persisted in most labeled neurons for at least 8 weeks. Following tracer application to dentin, the pulp tissue appeared normal histologically, with the exception that a layer of reactive dentin was deposited at the pulp-dentin border beneath the shallow cavities. Assessment of expression of calcitonin gene-related peptide (CGRP) and brain derived neurotrophic factor (BDNF) indicated that pulpal neurons remained in a quiescent, baseline condition cytochemically following application of tracer to cavities in dentin and upregulation of these markers could be detected in neurons that projected to teeth that received a test injury subsequent to tracer application. Thus, labeling of trigeminal neurons via dentinal tubules provides the basis for a useful model for precisely assessing properties of pulpal afferents in both quiescent and activated states.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Mantle cell lymphoma (MCL) is an aggressive B-cell malignancy for which novel therapeutics with improved efficacy are greatly needed. To provide support for clinical immune checkpoint blockade, we ...comprehensively evaluated the expression of therapeutically targetable immune checkpoint molecules on primary MCL cells. MCL cells showed constitutive expression of Programmed Death 1 (PD-1) and Programmed Death Ligand 1 (PD-L1), variable CD200, absent PD-L2, Lymphocyte Activation Gene 3 (LAG-3), and Cytotoxic T-cell Associated Protein 4 (CTLA-4). Effector cells from MCL patients expressed PD-1. Co-culture of MCL cells with T-cells induced PD-L1 surface expression, a phenomenon regulated by IFNγ and CD40:CD40L interaction. Induction of PD-L1 was attenuated by concurrent treatment with ibrutinib or duvelisib, suggesting BTK and PI3K are important mediators of PD-L1 expression. Overall, our data provide further insight into the expression of checkpoint molecules in MCL and support the use of PD-L1 blocking antibodies in MCL patients.
Full text
Available for:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Mantle cell lymphoma (MCL) is an incurable B-cell malignancy characterized by genetic dysregulation of cyclin D1 and activation of signaling pathways driving uncontrolled MCL cell proliferation and ...survival. Ibrutinib is an FDA-approved irreversible inhibitor of Bruton's tyrosine kinase (BTK), a downstream target of the B-cell receptor (BCR) pathway. While ibrutinib exhibits significant single-agent therapeutic activity in patients with relapsed/refractory MCL, the vast majority of MCL patients on ibrutinib progress with aggressive disease and short survival (3-8 mo). Although ~80% of chronic lymphocytic leukemia patients with acquired ibrutinib resistance have mutations in BTK and PLCγ2, this is uncommon in MCL suggesting alternative mechanisms driving this resistant phenotype. Understanding drug-resistance mechanisms and developing effective therapies for ibrutinib resistant (IR) MCL are urgently needed.
The major type II protein arginine methyltransferase enzyme, PRMT5, catalyzes symmetric dimethylation of arginine residues on histone tails (H3R8 and H4R3) and other proteins. PRMT5 regulates a vast array of biologic functions including RNA processing, DNA damage response, signal transduction, and gene expression. Amplified PRMT5 activity drives the expression and activity of key oncogenes (MYC, CYCLIND1, NOTCH1) while silencing expression and activity of tumor suppressors (ST7, RBL2, and p53). Our group has shown PRMT5 is overexpressed and dysregulated in MCL and strategies aimed at selectively targeting PRMT5 show anti-tumor activity in preclinical lymphoma models.
Here we describe the development of a novel patient derived xenograft (PDX) of IR-MCL and explore PRMT5 inhibition as an alternative therapeutic option to circumvent IR. Peripheral blood mononuclear cells from a 75 yo male patient diagnosed with acquired classic IR-MCL were engrafted intravenously into NSG mice. After 5 passages, all mice engrafted with 107 MCL cells developed histologically confirmed MCL infiltrating kidney, lymph nodes, bone marrow, spleen and peripheral blood. Circulating human CD5+/CD19+ cells were detectable and quantifiable by flow cytometry by day 21 post-engraftment. Karyotype analysis confirmed the hallmark t(11;14)(q13;q32) of MCL while retaining nearly all cytogenetic abnormalities present in the patient's primary tumor including a deletion of chromosome 9, associated with deletion of MTAP, a therapeutic vulnerability for PRMT5-targeted therapy. Whole exome sequencing confirmed genomic stability with successive passages. Ex vivo cytotoxicity assays and protein pathway analysis further confirmed resistance to ibrutinib (IC50 >1 µM) with maintained hyper-phosphorylation of AKT (Ser473) and ERK (Thr202/Tyr204). Western blot analysis showed elevated levels of c-MYC, CYCLIND1, BCL2, and pERK. After validation of circulating disease at day 25 post engraftment, mice were treated with either a novel small molecule inhibitor of PRMT5 (PRT382, 10 mg/kg orally 4 days on 3 days off) or ibrutinib (75 mg/kg administered in drinking water, n=5 mice per treatment group). Treatment of this PDX model with PRT382 resulted in significantly decreased disease burden and improved median survival compared to control animals from 48 to 83 days, respectively (p=0.0045). We found no significant difference in survival (p= 0.6540) or circulating disease burden with ibrutinib therapy compared to control group. The full BTK occupancy of ibrutinib treated mice was validated using fluorescence resonance energy transfer-based assay. Ex vivo PDX MCL cells from PRT382-treated mice showed loss of symmetric dimethyl arginine with preservation of asymmetric dimethyl arginine levels, reduced H4(Sme2)R3 epigenetic marks, and elevated levels of BCL2, MYC, and pAKT/pERK. We developed a cell line (SEFA) allowing for in vitro mechanistic studies. We are currently investigating potential mechanisms responsible for circumventing IR-MCL by integrating genome-wide changes to chromatin accessibility and whole transcriptome analysis.
This IR-MCL PDX mouse model serves as a useful tool to investigate mechanisms of drug resistance, provides a platform to explore novel pre-clinical therapeutic strategies to circumvent IR and demonstrates the therapeutic activity of PRMT5 targeted therapy in this aggressive disease.
Byrd:Pharmacyclics LLC, an AbbVie Company: Other: Travel Expenses, Research Funding, Speakers Bureau; Janssen: Consultancy, Other: Travel Expenses, Research Funding, Speakers Bureau; Ohio State University: Patents & Royalties: OSU-2S; Genentech: Research Funding; BeiGene: Research Funding; Janssen: Consultancy, Other: Travel Expenses, Research Funding, Speakers Bureau; TG Therapeutics: Other: Travel Expenses, Research Funding, Speakers Bureau; Gilead: Other: Travel Expenses, Research Funding, Speakers Bureau; Novartis: Other: Travel Expenses, Speakers Bureau; Genentech: Research Funding; Acerta: Research Funding; Acerta: Research Funding; Ohio State University: Patents & Royalties: OSU-2S; BeiGene: Research Funding; Genentech: Research Funding; BeiGene: Research Funding; Janssen: Consultancy, Other: Travel Expenses, Research Funding, Speakers Bureau; Novartis: Other: Travel Expenses, Speakers Bureau; Pharmacyclics LLC, an AbbVie Company: Other: Travel Expenses, Research Funding, Speakers Bureau; Gilead: Other: Travel Expenses, Research Funding, Speakers Bureau; Gilead: Other: Travel Expenses, Research Funding, Speakers Bureau; Novartis: Other: Travel Expenses, Speakers Bureau; Pharmacyclics LLC, an AbbVie Company: Other: Travel Expenses, Research Funding, Speakers Bureau; TG Therapeutics: Other: Travel Expenses, Research Funding, Speakers Bureau; Acerta: Research Funding; Ohio State University: Patents & Royalties: OSU-2S; TG Therapeutics: Other: Travel Expenses, Research Funding, Speakers Bureau. Vaddi:Prelude Therapeutics: Employment. Scherle:Prelude Therapeutics: Employment. Baiocchi:Prelude: Consultancy.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Mesodermal cells signal to neighboring epithelial cells to modulate their proliferation in both normal and disease states. We adapted a Caenorhabditis elegans organogenesis model to enable ...a genome-wide mesodermal-specific RNAi screen and discovered 39 factors in mesodermal cells that suppress the proliferation of adjacent Ras pathway-sensitized epithelial cells. These candidates encode components of protein complexes and signaling pathways that converge on the control of chromatin dynamics, cytoplasmic polyadenylation, and translation. Stromal fibroblast-specific deletion of mouse orthologs of several candidates resulted in the hyper-proliferation of mammary gland epithelium. Furthermore, a 33-gene signature of human orthologs was selectively enriched in the tumor stroma of breast cancer patients, and depletion of these factors from normal human breast fibroblasts increased proliferation of co-cultured breast cancer cells. This cross-species approach identified unanticipated regulatory networks in mesodermal cells with growth-suppressive function, exposing the conserved and selective nature of mesodermal-epithelial communication in development and cancer.
•Mesodermal suppressors of epithelial proliferation identified in C. elegans•Mesoderm-epithelial signaling components are highly conserved across species•Depletion of candidates in murine fibroblasts causes mammary hyper-proliferation•Human orthologs of identified genes are altered in breast cancer stroma
Liu, Dowdle, Khurshid, Sullivan et al. identify mesodermal factors in C. elegans that suppress growth of adjacent epithelial cells. These candidates are shown to have conserved function in murine contexts and to be altered in human breast cancer stroma.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
PDF
