Background: Central nervous system (CNS) metastases represent a major problem in the treatment of HER2-positive breast cancer due to the disappointing efficacy of HER2-targeted therapies in the brain microenvironment. The antibody-drug conjugate ado-trastuzumab emtansine (T-DM1) has shown efficacy in trastuzumab-resistant systemic breast cancer. Here, we tested the hypothesis that T-DM1 could overcome trastuzumab resistance in preclinical models of brain metastases.
Preclinical Efficacy of Ado-trastuzumab Emtansine in the Brain Microenvironment.
Specimen part, Disease, Time
View SamplesThe platelet-derived growth factor receptor alpha (PDGFR) exhibits divergent effects in skeletal muscle. At physiological levels, signaling through this receptor promotes muscle development in growing embryos and proper angiogenesis in regenerating adult muscle. However, either increased PDGF ligands or enhanced PDGFR pathway activity causes pathological fibrosis. This excessive collagen deposition, which is seen in aged and diseased muscle, interferes with proper muscle function and limits the effectiveness of gene- and cell-based therapies for muscle disorders. Although compelling evidence exists for the role of PDGFR in fibrosis, little is known about the cells through which this pathway acts. Here we show that PDGFR signaling regulates a population of muscle-resident fibro/adipogenic progenitors (FAPs) that play a supportive role in muscle regeneration but may also cause fibrosis when aberrantly regulated. We found that FAPs produce multiple transcriptional variants of PDGFR with different polyadenylation sites, including an intronic variant that codes for a protein isoform containing a truncated kinase domain. This variant, upregulated during regeneration, acts as a decoy to inhibit PDGF signaling and to prevent FAP over-activation. Moreover, increasing expression of this isoform limits fibrosis in vivo, suggesting both biological relevance and therapeutic potential of modulating polyadenylation patterns in stem cell populations.
Intronic polyadenylation of PDGFRα in resident stem cells attenuates muscle fibrosis.
Sex, Specimen part, Treatment
View SamplesThe platelet-derived growth factor receptor alpha (PDGFR) exhibits divergent effects in skeletal muscle. At physiological levels, signaling through this receptor promotes muscle development in growing embryos and proper angiogenesis in regenerating adult muscle. However, either increased PDGF ligands or enhanced PDGFR pathway activity causes pathological fibrosis. This excessive collagen deposition, which is seen in aged and diseased muscle, interferes with proper muscle function and limits the effectiveness of gene- and cell-based therapies for muscle disorders. Although compelling evidence exists for the role of PDGFR in fibrosis, little is known about the cells through which this pathway acts. Here we show that PDGFR signaling regulates a population of muscle-resident fibro/adipogenic progenitors (FAPs) that play a supportive role in muscle regeneration but may also cause fibrosis when aberrantly regulated. We found that FAPs produce multiple transcriptional variants of PDGFR with different polyadenylation sites, including an intronic variant that codes for a protein isoform containing a truncated kinase domain. This variant, upregulated during regeneration, acts as a decoy to inhibit PDGF signaling and to prevent FAP over-activation. Moreover, increasing expression of this isoform limits fibrosis in vivo, suggesting both biological relevance and therapeutic potential of modulating polyadenylation patterns in stem cell populations.
Intronic polyadenylation of PDGFRα in resident stem cells attenuates muscle fibrosis.
Sex, Specimen part, Treatment
View SamplesLactic acid bacteria confer a variety of health benefits. Here we investigate the mechanisms by which Lactobacillus brevis KB290 enhances cell-mediated cytotoxic activity. We fed a diet containing KB290 (3 10^9 colony-forming units/g) , or potato starch, to 9-week-old female BALB/c mice for 1, 4, 7, or 14 days and examined the cytotoxic activity of splenocytes was measured. RNA was extracted from the spleen and analyzed for gene expression by DNA microarray.
Effect of Lactobacillus brevis KB290 on the cell-mediated cytotoxic activity of mouse splenocytes: a DNA microarray analysis.
Sex, Age, Specimen part
View SamplesPersistent colonization of the gastric mucosa by Helicobacter pylori (Hp) elicits chronic inflammation and aberrant epithelial cell proliferation, which increases the risk of gastric cancer. We examined the ability of microRNAs to modulate gastric cell proliferation in response to persistent Hp infection and found that epigenetic silencing of miR-210 plays a key role in gastric disease progression. Importantly, DNA methylation of the miR-210 gene was increased in Hp-positive human gastric biopsies as compared to Hp-negative controls. Moreover silencing of miR-210 in gastric epithelial cells promoted proliferation. We identified STMN1 and DIMT1 as miR-210 target genes and demonstrated that inhibition of miR-210 expression augmented cell proliferation by activating STMN1 and DIMT1. Together, our results highlight inflammation-induced epigenetic silencing of miR-210 as a mechanism of induction of chronic gastric diseases, including cancer, during Hp infection.
Epigenetic silencing of miR-210 increases the proliferation of gastric epithelium during chronic Helicobacter pylori infection.
Cell line
View SamplesiPSC-derived NSPCs, which were induced by two different protocols (Embryoid body or Neural rosette) followed by expansion in free-floating culture (neurospheres), had closely resembled profiles.
Pathological classification of human iPSC-derived neural stem/progenitor cells towards safety assessment of transplantation therapy for CNS diseases.
Sex, Race
View SamplesThe entire small intestine was obseved by balloon endoscopy. Biopsy specimens were taken from jejunum, ileum and colon, respectively.
Reduced Human α-defensin 6 in Noninflamed Jejunal Tissue of Patients with Crohn's Disease.
Specimen part, Disease, Disease stage
View SamplesWe have previously established an in vitro tissue culture system (named VISUAL; Kondo et al., 2016), in which xylem and phloem differentiation can be induced with Arabidopsis thaliana cotyledons
BES1 and BZR1 Redundantly Promote Phloem and Xylem Differentiation.
Specimen part, Treatment, Time
View SamplesXylem consists of three types of cells: vessel cells, also referred to as tracheary elements (TEs), parenchyma cells, and fiber cells. TE differentiation includes two essential processes, programmed cell death (PCD) and secondary cell wall formation. These two processes are tightly coupled. However, little is known about the molecular mechanism of their gene regulation. Here, we show that VASCULAR-RELATED NAC-DOMAIN 6 (VND6), a master regulator of TEs, regulates these processes in a coordinated manner. We first identified specific genes downstream of VND6 by comparing them with those of SECONDARY WALL-ASSOCIATES NAC DOMAIN PROTEIN1 (SND1), a master regulator of xylem fiber cells, with transformed suspension culture cells in microarray experiments.
Arabidopsis VASCULAR-RELATED NAC-DOMAIN6 directly regulates the genes that govern programmed cell death and secondary wall formation during xylem differentiation.
Time
View SamplesMED23, a subunit of the Mediator coactivator complex, is important for the expression of a subset of MAPK/ERK pathway-dependent target genes; however, the genes in this subset varies between cell types. MAPK/ERK pathway-dependent processes are essential for T-cell development and function, but whether MED23 has a role in this context is unknown. We generated Med23 conditional knockout mice and induced Med23 deletion in early T cell development using the lineage specific Lck-Cre transgene. While the total cell number and distribution of cell populations in the thymuses of Med23flox/flox;Lck-Cre mice were essentially normal, MED23 null T-cells failed to efficiently populate the peripheral lymphoid organs. MED23 null thymocytes displayed decreased expression of the MAPK/ERK-responsive genes Egr1, Egr2, as well as of the membrane glycoprotein Cd52 (CAMPATH-1). MED23 null CD4 single-positive thymocytes also showed decreased expression of KLF2 (LKLF), a T cell master regulatory transcription factor. Indeed, similarities between the phenotypes of mice lacking MED23 or KLF2 in T-cells suggest that KLF2 deficiency in MED23 null T-cells is one of their key defects. Mechanistic experiments using MED23 null MEFs further suggest that MED23 is required for full activity of the MAPK-responsive transcription factor MEF2, which has previously been shown to mediate Klf2 expression. In summary, our data indicate that MED23 has critical roles in enabling T-cells to populate the peripheral lymphoid organs, possibly by potentiating MEF2-dependent expression of the T-cell transcription factor KLF2.
T-cells null for the MED23 subunit of mediator express decreased levels of KLF2 and inefficiently populate the peripheral lymphoid organs.
Sex, Specimen part
View Samples