Generation of ROR gamma t(+) Antigen-Specific T Regulatory 17 Cells from Foxp3(+) Precursors in Autoimmunity

Th17 cells are potent mediators in autoimmune diseases, and RORgt is required for their development. Recent studies have shown that ROR gamma t(+) Treg cells in the gut regulate intestinal inflammation by inhibiting effector T cell function. In the current study, we report that ROR gamma t(+) Treg cells were also found in lymph nodes following immunization. Not only distinct from intestinal ROR gamma t(+) Treg cells in their transcriptomes, peripheral ROR gamma t(+) Treg cells were derived from Foxp3(+) thymic Treg cells in an antigen-specific manner. Development of these ROR gamma t(+) Treg cells, coined T regulatory 17 (Tr17) cells, depended on IL-6/Stat3 signaling. Tr17 cells showed suppressive activity against antigen-specific effector T cells in vitro. In addition, Tr17 cells efficiently inhibited myelin-specific Th17-cell-mediated CNS auto-inflammation in a passive EAE model. Collectively, our study demonstrates that Tr17 cells are effector Treg cells that potentially restrict autoimmunity.</p

RNA Toxicity from the ALS/FTD C9ORF72 Expansion Is Mitigated by Antisense Intervention

A hexanucleotide GGGGCC repeat expansion in the noncoding region of the C9ORF72 gene is the most common genetic abnormality in familial and sporadic amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The function of the C9ORF72 protein is unknown, as is the mechanism by which the repeat expansion could cause disease. Induced pluripotent stem cell (iPSC)-differentiated neurons from C9ORF72 ALS patients revealed disease-specific (1) intranuclear GGGGCCexp RNA foci, (2) dysregulated gene expression, (3) sequestration of GGGGCCexp RNA binding protein ADARB2, and (4) susceptibility to excitotoxicity. These pathological and pathogenic characteristics were confirmed in ALS brain and were mitigated with antisense oligonucleotide (ASO) therapeutics to the C9ORF72 transcript or repeat expansion despite the presence of repeat-associated non-ATG translation (RAN) products. These data indicate a toxic RNA gain-of-function mechanism as a cause of C9ORF72 ALS and provide candidate antisense therapeutics and candidate human pharmacodynamic markers for therapy

Mutational Profiles Reveal an Aberrant TGF-β-CEA Regulated Pathway in Colon Adenomas.

Mutational processes and signatures that drive early tumorigenesis are centrally important for early cancer prevention. Yet, to date, biomarkers and risk factors for polyps (adenomas) that inordinately and rapidly develop into colon cancer remain poorly defined. Here, we describe surprisingly high mutational profiles through whole-genome sequence (WGS) analysis in 2 of 4 pairs of benign colorectal adenoma tissue samples. Unsupervised hierarchical clustered transcriptomic analysis of a further 7 pairs of adenomas reveals distinct mutational signatures regardless of adenoma size. Transitional single nucleotide substitutions of C:G>T:A predominate in the adenoma mutational spectrum. Strikingly, we observe mutations in the TGF-β pathway and CEA-associated genes in 4 out of 11 adenomas, overlapping with the Wnt pathway. Immunohistochemical labeling reveals a nearly 5-fold increase in CEA levels in 23% of adenoma samples with a concomitant loss of TGF-β signaling. We also define a functional role by which the CEA B3 domain interacts with TGFBR1, potentially inactivating the tumor suppressor function of TGF-β signaling. Our study uncovers diverse mutational processes underlying the transition from early adenoma to cancer. This has broad implications for biomarker-driven targeting of CEA/TGF-β in high-risk adenomas and may lead to early detection of aggressive adenoma to CRC progression

ILF2 Is a Regulator of RNA Splicing and DNA Damage Response in 1q21-Amplified Multiple Myeloma

Amplification of 1q21 occurs in approximately 30% of de novo and 70% of relapsed multiple myeloma (MM) and is correlated with disease progression and drug resistance. Here, we provide evidence that the 1q21 amplification-driven overexpression of ILF2 in MM promotes tolerance of genomic instability and drives resistance to DNA-damaging agents. Mechanistically, elevated ILF2 expression exerts resistance to genotoxic agents by modulating YB-1 nuclear localization and interaction with the splicing factor U2AF65, which promotes mRNA processing and the stabilization of transcripts involved in homologous recombination in response to DNA damage. The intimate link between 1q21-amplified ILF2 and the regulation of RNA splicing of DNA repair genes may be exploited to optimize the use of DNA-damaging agents in patients with high-risk MM

Telomere Dysfunction Drives Aberrant Hematopoietic Differentiation and Myelodysplastic Syndrome

SummaryMyelodysplastic syndrome (MDS) risk correlates with advancing age, therapy-induced DNA damage, and/or shorter telomeres, but whether telomere erosion directly induces MDS is unknown. Here, we provide the genetic evidence that telomere dysfunction-induced DNA damage drives classical MDS phenotypes and alters common myeloid progenitor (CMP) differentiation by repressing the expression of mRNA splicing/processing genes, including SRSF2. RNA-seq analyses of telomere dysfunctional CMP identified aberrantly spliced transcripts linked to pathways relevant to MDS pathogenesis such as genome stability, DNA repair, chromatin remodeling, and histone modification, which are also enriched in mouse CMP haploinsufficient for SRSF2 and in CD34+ CMML patient cells harboring SRSF2 mutation. Together, our studies establish an intimate link across telomere biology, aberrant RNA splicing, and myeloid progenitor differentiation

TGF-β/β2-spectrin/CTCF-regulated tumor suppression in human stem cell disorder Beckwith-Wiedemann syndrome.

Beckwith-Wiedemann syndrome (BWS) is a human stem cell disorder, and individuals with this disease have a substantially increased risk (~800-fold) of developing tumors. Epigenetic silencing of β2-spectrin (β2SP, encoded by SPTBN1), a SMAD adaptor for TGF-β signaling, is causally associated with BWS; however, a role of TGF-β deficiency in BWS-associated neoplastic transformation is unexplored. Here, we have reported that double-heterozygous Sptbn1(+/–) Smad3(+/–) mice, which have defective TGF-β signaling, develop multiple tumors that are phenotypically similar to those of BWS patients. Moreover, tumorigenesis-associated genes IGF2 and telomerase reverse transcriptase (TERT) were overexpressed in fibroblasts from BWS patients and TGF-β–defective mice. We further determined that chromatin insulator CCCTC-binding factor (CTCF) is TGF-β inducible and facilitates TGF-β–mediated repression of TERT transcription via interactions with β2SP and SMAD3. This regulation was abrogated in TGF-β–defective mice and BWS, resulting in TERT overexpression. Imprinting of the IGF2/H19 locus and the CDKN1C/KCNQ1 locus on chromosome 11p15.5 is mediated by CTCF, and this regulation is lost in BWS, leading to aberrant overexpression of growth-promoting genes. Therefore, we propose that loss of CTCF-dependent imprinting of tumor-promoting genes, such as IGF2 and TERT, results from a defective TGF-β pathway and is responsible at least in part for BWS-associated tumorigenesis as well as sporadic human cancers that are frequently associated with SPTBN1 and SMAD3 mutations

Enhanced expression of CEA correlates with loss of TGF-β signaling in early colon adenomas.

<p>(A) Marked increases in CEA mRNA expression levels in the highly mutated adenoma samples, MDA27ad-TA and MDA34ad-TVA. CEA mRNA expression levels were detected in 4 adenomas (MDA27ad-TA, MDA34ad-TVA, MDA2ad-TVA, and MDA3ad-SSA) and 4 matched normal mucosa samples (MDA27nor, MDA34nor, MDA2nor, and MDA3nor) by Q-RT-PCR. Results are the average of three independent experiments and are presented as mean ± SD. *<i>p</i> < 0.01, versus normal tissues, Student’s t-test. (B) Analysis of an Oncomine™ dataset demonstrates high CEA mRNA levels in colon and rectal adenomas compared to that in corresponding normal colorectal tissue. CEA and CEACAM6 mRNA expression is inversely associated with TGF-β target gene levels in normal and adenoma colorectal tissues. Transcriptomic profiles of 32 colorectal adenoma tumors and their 32 corresponding normal colorectal tissue were downloaded from Gene Expression Omnibus database (data set GSE8671). These gene expression profiles were then analyzed using Oncomine analysis tools (<a href="http://www.oncomine.org/" target="_blank">www.oncomine.org</a>). Data are displayed as a heat map using an Oncomine™ graphic platform and as a dot plot using a GraphPad Prism v5.0 program. *: <i>p</i> < 0.05, Student’s t-test. (C) Adenoma samples analysis of CEA, TGFBR1, TGFBR2, and β2SP reveals a negative correlation between CEA and TGF-β genes in colon adenomas. Sections from human clinical samples of normal (n = 10) and adenoma colon tissue (n = 26) were prepared and processed for immunohistochemical analysis, with further confirmation using 40 adenomas. Magnification × 20; insets magnification × 60. Scale bars, 10 mm. Quantification of the immunohistochemical staining is shown. Mean ± SD is shown *: <i>p</i> < 0.01, Student’s t-test.</p