Publications

2019
Aaron Goldman, Joshua L Smalley, Meeta Mistry, Harald Krenzlin, Hong Zhang, Andrew Dhawan, Barbara Caldarone, Stephen J Moss, David A Silbersweig, Sean E Lawler, and Ilana M Braun. 2019. “A computationally inspired in-vivo approach identifies a link between amygdalar transcriptional heterogeneity, socialization and anxiety.” Transl Psychiatry, 9, 1, Pp. 336.Abstract
Pharmaceutical breakthroughs for anxiety have been lackluster in the last half-century. Converging behavior and limbic molecular heterogeneity has the potential to revolutionize biomarker-driven interventions. However, current in vivo models too often deploy artificial systems including directed evolution, mutations and fear induction, which poorly mirror clinical manifestations. Here, we explore transcriptional heterogeneity of the amygdala in isogenic mice using an unbiased multi-dimensional computational approach that segregates intra-cohort reactions to moderate situational adversity and intersects it with high content molecular profiling. We show that while the computational approach stratifies known features of clinical anxiety including nitric oxide, opioid and corticotropin signaling, previously unrecognized druggable biomarkers emerge, such as calpain11 and scand1. Through ingenuity pathway analyses, we further describe a role for neurosteroid estradiol signaling, heat shock proteins, ubiquitin ligases and lipid metabolism. In addition, we report a remarkable behavioral pattern that maps to molecular features of anxiety in mice through counterphobic social attitudes, which manifest as increased, yet spatially distant socialization. These findings provide an unbiased approach for interrogating anxiolytics, and hint toward biomarkers underpinning behavioral and social patterns that merit further exploration.
Yang Zheng, Pin Liu, Ling Bai, James S Trimmer, Bruce P Bean, and David D Ginty. 2019. “Deep Sequencing of Somatosensory Neurons Reveals Molecular Determinants of Intrinsic Physiological Properties.” Neuron, 103, 4, Pp. 598-616.e7.Abstract
Dorsal root ganglion (DRG) sensory neuron subtypes defined by their in vivo properties display distinct intrinsic electrical properties. We used bulk RNA sequencing of genetically labeled neurons and electrophysiological analyses to define ion channel contributions to the intrinsic electrical properties of DRG neuron subtypes. The transcriptome profiles of eight DRG neuron subtypes revealed differentially expressed and functionally relevant genes, including voltage-gated ion channels. Guided by these data, electrophysiological analyses using pharmacological and genetic manipulations as well as computational modeling of DRG neuron subtypes were undertaken to assess the functions of select voltage-gated potassium channels (Kv1, Kv2, Kv3, and Kv4) in shaping action potential (AP) waveforms and firing patterns. Our findings show that the transcriptome profiles have predictive value for defining ion channel contributions to sensory neuron subtype-specific intrinsic physiological properties. The distinct ensembles of voltage-gated ion channels predicted to underlie the unique intrinsic physiological properties of eight DRG neuron subtypes are presented.
Long Zhao, Raz Ben-Yair, Caroline E Burns, and Geoffrey C Burns. 2019. “Endocardial Notch Signaling Promotes Cardiomyocyte Proliferation in the Regenerating Zebrafish Heart through Wnt Pathway Antagonism.” Cell Rep, 26, 3, Pp. 546-554.e5.Abstract
Previous studies demonstrate that the regenerative zebrafish heart responds to injury by upregulating Notch receptors in the endocardium and epicardium. Moreover, global suppression of Notch activity following injury impairs cardiomyocyte proliferation and induces scarring. However, the lineage-specific requirements for Notch signaling and full array of downstream targets remain unidentified. Here, we demonstrate that inhibition of endocardial Notch signaling following ventricular amputation compromises cardiomyocyte proliferation and stimulates fibrosis. RNA sequencing uncovered reduced levels of two transcripts encoding secreted Wnt antagonists, Wif1 and Notum1b, in Notch-suppressed hearts. Like Notch receptors, wif1 and notum1b are induced following injury in the endocardium and epicardium. Small-molecule-mediated activation of Wnt signaling is sufficient to impair cardiomyocyte proliferation and induce scarring. Last, Wnt pathway suppression partially restored cardiomyocyte proliferation in hearts experiencing endocardial Notch inhibition. Taken together, our data demonstrate that Notch signaling supports cardiomyocyte proliferation by dampening myocardial Wnt activity during zebrafish heart regeneration.
Irfete S Fetahu, Dingailu Ma, Kimberlie Rabidou, Christian Argueta, Michael SMITH, Hang Liu, Feizhen Wu, and Yujiang G Shi. 2019. “Epigenetic signatures of methylated DNA cytosine in Alzheimer's disease.” Sci Adv, 5, 8, Pp. eaaw2880.Abstract
Alzheimer's disease (AD), a progressive neurodegenerative disorder, is the most common untreatable form of dementia. Identifying molecular biomarkers that allow early detection remains a key challenge in the diagnosis, treatment, and prognostic evaluation of the disease. Here, we report a novel experimental and analytical model characterizing epigenetic alterations during AD onset and progression. We generated the first integrated base-resolution genome-wide maps of the distribution of 5-methyl-cytosine (5mC), 5-hydroxymethyl-cytosine (5hmC), and 5-formyl/carboxy-cytosine (5fC/caC) in normal and AD neurons. We identified 27 AD region-specific and 39 CpG site-specific epigenetic signatures that were independently validated across our familial and sporadic AD models, and in an independent clinical cohort. Thus, our work establishes a new model and strategy to study the epigenetic alterations underlying AD onset and progression and provides a set of highly reliable AD-specific epigenetic signatures that may have early diagnostic and prognostic implications.
Eleni Anastasiadou, Dina Stroopinsky, Stella Alimperti, Alan L Jiao, Athalia R Pyzer, Claudia Cippitelli, Giuseppina Pepe, Martina Severa, Jacalyn Rosenblatt, Marilena P Etna, Simone Rieger, Bettina Kempkes, Eliana M Coccia, Shannan Ho J Sui, Christopher S Chen, Stefania Uccini, David Avigan, Alberto Faggioni, Pankaj Trivedi, and Frank J Slack. 2019. “Epstein-Barr virus-encoded EBNA2 alters immune checkpoint PD-L1 expression by downregulating miR-34a in B-cell lymphomas.” Leukemia, 33, 1, Pp. 132-147.Abstract
Cancer cells subvert host immune surveillance by altering immune checkpoint (IC) proteins. Some Epstein-Barr virus (EBV)-associated tumors have higher Programmed Cell Death Ligand, PD-L1 expression. However, it is not known how EBV alters ICs in the context of its preferred host, the B lymphocyte and in derived lymphomas. Here, we found that latency III-expressing Burkitt lymphoma (BL), diffuse large B-cell lymphomas (DLBCL) or their EBNA2-transfected derivatives express high PD-L1. In a DLBCL model, EBNA2 but not LMP1 is sufficient to induce PD-L1. Latency III-expressing DLBCL biopsies showed high levels of PD-L1. The PD-L1 targeting oncosuppressor microRNA miR-34a was downregulated in EBNA2-transfected lymphoma cells. We identified early B-cell factor 1 (EBF1) as a repressor of miR-34a transcription. Short hairpin RNA (shRNA)-mediated knockdown of EBF1 was sufficient to induce miR-34a transcription, which in turn reduced PD-L1. MiR-34a reconstitution in EBNA2-transfected DLBCL reduced PD-L1 expression and increased its immunogenicity in mixed lymphocyte reactions (MLR) and in three-dimensional biomimetic microfluidic chips. Given the importance of PD-L1 inhibition in immunotherapy and miR-34a dysregulation in cancers, our findings may have important implications for combinatorial immunotherapy, which include IC inhibiting antibodies and miR-34a, for EBV-associated cancers.
Abby L Olsen and Mel B Feany. 2019. “Glial α-synuclein promotes neurodegeneration characterized by a distinct transcriptional program in vivo.” Glia, 67, 10, Pp. 1933-1957.Abstract
α-Synucleinopathies are neurodegenerative diseases that are characterized pathologically by α-synuclein inclusions in neurons and glia. The pathologic contribution of glial α-synuclein in these diseases is not well understood. Glial α-synuclein may be of particular importance in multiple system atrophy (MSA), which is defined pathologically by glial cytoplasmic α-synuclein inclusions. We have previously described Drosophila models of neuronal α-synucleinopathy, which recapitulate key features of the human disorders. We have now expanded our model to express human α-synuclein in glia. We demonstrate that expression of α-synuclein in glia alone results in α-synuclein aggregation, death of dopaminergic neurons, impaired locomotor function, and autonomic dysfunction. Furthermore, co-expression of α-synuclein in both neurons and glia worsens these phenotypes as compared to expression of α-synuclein in neurons alone. We identify unique transcriptomic signatures induced by glial as opposed to neuronal α-synuclein. These results suggest that glial α-synuclein may contribute to the burden of pathology in the α-synucleinopathies through a cell type-specific transcriptional program. This new Drosophila model system enables further mechanistic studies dissecting the contribution of glial and neuronal α-synuclein in vivo, potentially shedding light on mechanisms of disease that are especially relevant in MSA but also the α-synucleinopathies more broadly.
Wantae Kim, Yong Suk Cho, Xiaohui Wang, Ogyi Park, Xueyan Ma, Hanjun Kim, Wenjian Gan, Eek-Hoon Jho, Boksik Cha, Yun-Ji Jeung, Lei Zhang, Bin Gao, Wenyi Wei, Jin Jiang, Kyung-Sook Chung, and Yingzi Yang. 2019. “Hippo signaling is intrinsically regulated during cell cycle progression by APC/C.” Proc Natl Acad Sci U S A, 116, 19, Pp. 9423-9432.Abstract
The Hippo-YAP/TAZ signaling pathway plays a pivotal role in growth control during development and regeneration and its dysregulation is widely implicated in various cancers. To further understand the cellular and molecular mechanisms underlying Hippo signaling regulation, we have found that activities of core Hippo signaling components, large tumor suppressor (LATS) kinases and YAP/TAZ transcription factors, oscillate during mitotic cell cycle. We further identified that the anaphase-promoting complex/cyclosome (APC/C) E3 ubiquitin ligase complex, which plays a key role governing eukaryotic cell cycle progression, intrinsically regulates Hippo signaling activities. CDH1 recognizes LATS kinases to promote their degradation and, hence, YAP/TAZ regulation by LATS phosphorylation is under cell cycle control. As a result, YAP/TAZ activities peak in G1 phase. Furthermore, we show in eye and wing development that Cdh1 is required in vivo to regulate the LATS homolog Warts with a conserved mechanism. Cdh1 reduction increased Warts levels, which resulted in reduction of the eye and wing sizes in a Yorkie dependent manner. Therefore, LATS degradation by APC/C represents a previously unappreciated and evolutionarily conserved layer of Hippo signaling regulation.
Alan L Jiao, Roberto Perales, Neil T Umbreit, Jeffrey R Haswell, Mary E Piper, Brian D Adams, David Pellman, Scott Kennedy, and Frank J Slack. 2019. “Human nuclear RNAi-defective 2 (NRDE2) is an essential RNA splicing factor.” RNA, 25, 3, Pp. 352-363.Abstract
The accurate inheritance of genetic material is a basic necessity in all domains of life and an unexpectedly large number of RNA processing factors are required for mitotic progression and genome stability. NRDE2 (nuclear RNAi defective-2) is an evolutionarily conserved protein originally discovered for its role in nuclear RNA interference (RNAi) and heritable gene silencing in (). The function of the human gene remains poorly understood. Here we show that human NRDE2 is an essential protein required for suppressing intron retention in a subset of pre-mRNAs containing short, GC-rich introns with relatively weak 5' and 3' splice sites. NRDE2 preferentially interacts with components of the U5 small nuclear ribonucleoprotein (snRNP), the exon junction complex, and the RNA exosome. Interestingly, depleted cells exhibit greatly increased levels of genomic instability and DNA damage, as well as defects in centrosome maturation and mitotic progression. We identify the essential centriolar satellite protein, CEP131, as a direct NRDE2-regulated target. NRDE2 specifically binds to and promotes the efficient splicing of pre-mRNA, and depleting dramatically reduces CEP131 protein expression, contributing to impaired recruitment of critical centrosomal proteins (e.g., γ-tubulin and Aurora Kinase A) to the spindle poles during mitosis. Our work establishes a conserved role for human in RNA splicing, characterizes the severe genomic instability phenotypes observed upon loss of , and highlights the direct regulation of splicing as one of multiple mechanisms through which such phenotypes might be explained.
Melissa L Hancock, Rebecca C Meyer, Meeta Mistry, Radhika S Khetani, Alexandre Wagschal, Taehwan Shin, Shannan J Ho Sui, Anders M Näär, and John G Flanagan. 2019. “Insulin Receptor Associates with Promoters Genome-wide and Regulates Gene Expression.” Cell, 177, 3, Pp. 722-736.e22.Abstract
Insulin receptor (IR) signaling is central to normal metabolic control and dysregulated in prevalent chronic diseases. IR binds insulin at the cell surface and transduces rapid signaling via cytoplasmic kinases. However, mechanisms mediating long-term effects of insulin remain unclear. Here, we show that IR associates with RNA polymerase II in the nucleus, with striking enrichment at promoters genome-wide. The target genes were highly enriched for insulin-related functions including lipid metabolism and protein synthesis and diseases including diabetes, neurodegeneration, and cancer. IR chromatin binding was increased by insulin and impaired in an insulin-resistant disease model. Promoter binding by IR was mediated by coregulator host cell factor-1 (HCF-1) and transcription factors, revealing an HCF-1-dependent pathway for gene regulation by insulin. These results show that IR interacts with transcriptional machinery at promoters and identify a pathway regulating genes linked to insulin's effects in physiology and disease.
Jaclyn Sceneay, Gregory J Goreczny, Kristin Wilson, Sara Morrow, Molly J DeCristo, Jessalyn M Ubellacker, Yuanbo Qin, Tyler Laszewski, Daniel G Stover, Victor Barrera, John N Hutchinson, Rachel A Freedman, Elizabeth A Mittendorf, and Sandra S McAllister. 2019. “Interferon Signaling Is Diminished with Age and Is Associated with Immune Checkpoint Blockade Efficacy in Triple-Negative Breast Cancer.” Cancer Discov, 9, 9, Pp. 1208-1227.Abstract
Immune checkpoint blockade (ICB) therapy, which targets T cell-inhibitory receptors, has revolutionized cancer treatment. Among the breast cancer subtypes, evaluation of ICB has been of greatest interest in triple-negative breast cancer (TNBC) due to its immunogenicity, as evidenced by the presence of tumor-infiltrating lymphocytes and elevated PD-L1 expression relative to other subtypes. TNBC incidence is equally distributed across the age spectrum, affecting 10% to 15% of women in all age groups. Here we report that increased immune dysfunction with age limits ICB efficacy in aged TNBC-bearing mice. The tumor microenvironment in both aged mice and patients with TNBC shows decreased IFN signaling and antigen presentation, suggesting failed innate immune activation with age. Triggering innate immune priming with a STING agonist restored response to ICB in aged mice. Our data implicate age-related immune dysfunction as a mechanism of ICB resistance in mice and suggest potential prognostic utility of assessing IFN-related genes in patients with TNBC receiving ICB therapy. SIGNIFICANCE: These data demonstrate for the first time that age determines the T cell-inflamed phenotype in TNBC and affects response to ICB in mice. Evaluating IFN-related genes from tumor genomic data may aid identification of patients for whom combination therapy including an IFN pathway activator with ICB may be required..
Peiyan Ni, Haneul Noh, Zhicheng Shao, Qian Zhu, Youxin Guan, Joshua J Park, Fatima Arif, James M Park, Chiderah Abani, Cameron Beaudreault, Joy S Park, Elizabeth Berry, Alexander Moghadam, Patric Stanton, John N Hutchinson, Bill Andrews, Clare Faux, John Parnevelas, Leonard M Eisenberg, Kyungjoon Park, Vadim Y Bolshakov, and Sangmi Chung. 2019. “Large-Scale Generation and Characterization of Homogeneous Populations of Migratory Cortical Interneurons from Human Pluripotent Stem Cells.” Mol Ther Methods Clin Dev, 13, Pp. 414-430.Abstract
During development, cortical interneurons (cINs) are generated from the ventral telencephalon, robustly migrate to the dorsal telencephalon, make local synaptic connections, and critically regulate brain circuitry by inhibiting other neurons. Thus, their abnormality is associated with various brain disorders. Human pluripotent stem cell (hPSC)-derived cINs can provide unlimited sources with which to study the pathogenesis mechanism of these disorders as well as provide a platform to develop novel therapeutics. By employing spinner culture, we could obtain a >10-fold higher yield of cIN progenitors compared to conventional culture without affecting their phenotype. Generated cIN spheres can be maintained feeder-free up to 10 months and are optimized for passaging and cryopreservation. In addition, we identified a combination of chemicals that synchronously matures generated progenitors into SOX6KI67 migratory cINs and extensively characterized their maturation in terms of metabolism, migration, arborization, and electrophysiology. When transplanted into mouse brains, chemically matured migratory cINs generated grafts that efficiently disperse and integrate into the host circuitry without uncontrolled growth, making them an optimal cell population for cell therapy. Efficient large-scale generation of homogeneous migratory cINs without the need of feeder cells will play a critical role in the full realization of hPSC-derived cINs for development of novel therapeutics.
Lisa W Witten, Christopher J Cheng, and Frank J Slack. 2019. “miR-155 drives oncogenesis by promoting and cooperating with mutations in the c-Kit oncogene.” Oncogene, 38, 12, Pp. 2151-2161.Abstract
MicroRNAs (miRNAs) have emerged as crucial players in the development and maintenance of disease. miR-155 is an inflammation-associated, oncogenic miRNA, frequently overexpressed in hematological malignancies and solid tumors. However, the mechanism of oncogenesis by miR-155 is not well characterized, and research has focused primarily on individual, direct targets, which does not recapitulate the complexities of cancer. Using a powerful, inducible transgenic mouse model that overexpresses miR-155 and develops miR-155-addicted hematological malignancy, we describe here a multi-step process of oncogenesis by miR-155, which involves cooperation between miR-155, its direct targets, and other oncogenes. miR-155 is known to target DNA-repair proteins, leading to a mutator phenotype, and we find that over 93% of tumors in our miR-155 overexpressing mice contain activating mutations in a single oncogene, c-Kit. Treating mice with dasatinib or imatinib, which target c-Kit, resulted in complete tumor regression, indicating that c-Kit activity is crucial in the oncogenic process. Interestingly, c-Kit expression is high when miR-155 is overexpressed, indicating further cooperation between miR-155 and c-Kit. Our findings support a multi-step model of oncogenesis by miR-155 in which miR-155 promotes both a mutator phenotype and a cellular environment particularly susceptible to mutations in a given oncogene.
Mira Pavkovic, Lorena Pantano, Cory V Gerlach, Sergine Brutus, Sarah A Boswell, Robert A Everley, Jagesh V Shah, Shannan H Sui, and Vishal S Vaidya. 2019. “Multi omics analysis of fibrotic kidneys in two mouse models.” Sci Data, 6, 1, Pp. 92.Abstract
Kidney fibrosis represents an urgent unmet clinical need due to the lack of effective therapies and an inadequate understanding of the molecular pathogenesis. We have generated a comprehensive and combined multi-omics dataset (proteomics, mRNA and small RNA transcriptomics) of fibrotic kidneys that is searchable through a user-friendly web application: http://hbcreports.med.harvard.edu/fmm/ . Two commonly used mouse models were utilized: a reversible chemical-induced injury model (folic acid (FA) induced nephropathy) and an irreversible surgically-induced fibrosis model (unilateral ureteral obstruction (UUO)). mRNA and small RNA sequencing, as well as 10-plex tandem mass tag (TMT) proteomics were performed with kidney samples from different time points over the course of fibrosis development. The bioinformatics workflow used to process, technically validate, and combine the single omics data will be described. In summary, we present temporal multi-omics data from fibrotic mouse kidneys that are accessible through an interrogation tool (Mouse Kidney Fibromics browser) to provide a searchable transcriptome and proteome for kidney fibrosis researchers.
Aron Gyuris, Jose Navarrete-Perea, Ala Jo, Simona Cristea, Shuang Zhou, Kyle Fraser, Zhiyun Wei, Anna M Krichevsky, Ralph Weissleder, Hakho Lee, Steve P Gygi, and Al Charest. 2019. “Physical and Molecular Landscapes of Mouse Glioma Extracellular Vesicles Define Heterogeneity.” Cell Rep, 27, 13, Pp. 3972-3987.e6.Abstract
Cancer extracellular vesicles (EVs) are highly heterogeneous, which impedes our understanding of their function as intercellular communication agents and biomarkers. To deconstruct this heterogeneity, we analyzed extracellular RNAs (exRNAs) and extracellular proteins (exPTNs) from size fractionation of large, medium, and small EVs and ribonucleoprotein complexes (RNPs) from mouse glioblastoma cells by RNA sequencing and quantitative proteomics. mRNA from medium-sized EVs most closely reflects the cellular transcriptome, whereas small EV exRNA is enriched in small non-coding RNAs and RNPs contain precisely processed tRNA fragments. The exPTN composition of EVs and RNPs reveals that they are closely related by vesicle type, independent of their cellular origin, and single EV analysis reveals that small EVs are less heterogeneous in their protein content than larger ones. We provide a foundation for better understanding of segregation of macromolecules in glioma EVs through a catalog of diverse exRNAs and exPTNs.
Yiran Dong, Robert A Sanford, William P Inskeep, Vaibhav Srivastava, Vincent Bulone, Christopher J Fields, Peter M Yau, Mayandi Sivaguru, Dag Ahrén, Kyle W Fouke, Joseph Weber, Charles R Werth, Isaac K Cann, Kathleen M Keating, Radhika S Khetani, Alvaro G Hernandez, Chris Wright, Mark Band, Brian S Imai, Glenn A Fried, and Bruce W Fouke. 2019. “Physiology, Metabolism, and Fossilization of Hot-Spring Filamentous Microbial Mats.” Astrobiology, 19, 12, Pp. 1442-1458.Abstract
The evolutionarily ancient Aquificales bacterium spp. dominates filamentous microbial mat communities in shallow, fast-flowing, and dysoxic hot-spring drainage systems around the world. In the present study, field observations of these fettuccini-like microbial mats at Mammoth Hot Springs in Yellowstone National Park are integrated with geology, geochemistry, hydrology, microscopy, and multi-omic molecular biology analyses. Strategic sampling of living filamentous mats along with the hot-spring CaCO () in which they are actively being entombed and fossilized has permitted the first direct linkage of spp. physiology and metabolism with the formation of distinct travertine streamer microbial biomarkers. Results indicate that, during chemoautotrophy and CO carbon fixation, the 87-98% -dominated mats utilize chaperons to facilitate enzyme stability and function. High-abundance transcripts and proteins for type IV pili and extracellular polymeric substances (EPSs) are consistent with their strong mucus-rich filaments tens of centimeters long that withstand hydrodynamic shear as they become encrusted by more than 5 mm of travertine per day. Their primary energy source is the oxidation of reduced sulfur ( sulfide, sulfur, or thiosulfate) and the simultaneous uptake of extremely low concentrations of dissolved O facilitated by bd-type cytochromes. The formation of elevated travertine ridges permits the -dominated mats to create a shallow platform from which to access low levels of dissolved oxygen at the virtual exclusion of other microorganisms. These ridged travertine streamer microbial biomarkers are well preserved and create a robust fossil record of microbial physiological and metabolic activities in modern and ancient hot-spring ecosystems.
Heng-Jia Liu, Hilaire C Lam, Christian V Baglini, Julie Nijmeh, Alischer A Cottrill, Stephen Y Chan, and Elizabeth P Henske. 2019. “Rapamycin-upregulated miR-29b promotes mTORC1-hyperactive cell growth in TSC2-deficient cells by downregulating tumor suppressor retinoic acid receptor β (RARβ).” Oncogene, 38, 49, Pp. 7367-7383.Abstract
miR-29b has been identified as a rapamycin-induced microRNA (miRNA) in Tsc2-deficient, mTORC1-hyperactive cells. The biological significance of this induction of miR-29b is unknown. We have found that miR-29b acts as an oncogenic miRNA in Tsc2-deficient cells: inhibition of miR-29b suppressed cell proliferation, anchorage-independent cell growth, cell migration, invasion, and the growth of Tsc2-deficient tumors in vivo. Importantly, the combination of miR-29b inhibition with rapamycin treatment further inhibited these tumor-associated cellular processes. To gain insight into the molecular mechanisms by which miR-29b promotes tumorigenesis, we used RNA sequencing to identify the tumor suppressor retinoid receptor beta (RARβ) as a target gene of miR-29b. We found that miR-29b directly targeted the 3'UTR of RARβ. Forced expression of RARβ reversed the effects of miR-29b overexpression in proliferation, migration, and invasion, indicating that it is a critical target. miR-29b expression correlated with low RARβ expression in renal clear cell carcinomas and bladder urothelial carcinomas, tumors associated with TSC gene mutations. We further identified growth family member 4 (ING4) as a novel interacting partner of RARβ. Overexpression of ING4 inhibited the migration and invasion of Tsc2-deficient cells while silencing of ING4 reversed the RARβ-mediated suppression of cell migration and invasion. Taken together, our findings reveal a novel miR-29b/RARβ/ING4 pathway that regulates tumorigenic properties of Tsc2-deficient cells, and that may serve as a potential therapeutic target for TSC, lymphangioleiomyomatosis (LAM), and other mTORC1-hyperactive tumors.
Ahmad Al-Moujahed, Bo Tian, Nikolaos E Efstathiou, Eleni K Konstantinou, Mien Hoang, Haijiang Lin, Joan W Miller, and Demetrios G Vavvas. 2019. “Receptor interacting protein kinase 3 (RIP3) regulates iPSCs generation through modulating cell cycle progression genes.” Stem Cell Res, 35, Pp. 101387.Abstract
The molecular mechanisms involved in induced pluripotent stem cells (iPSCs) generation are poorly understood. The cell death machinery of apoptosis-inducing caspases have been shown to facilitate the process of iPSCs reprogramming. However, the effect of other cell death processes, such as programmed necrosis (necroptosis), on iPSCs induction has not been studied. In this study, we investigated the role of receptor-interacting protein kinase 3 (RIP3), an essential regulator of necroptosis, in reprogramming mouse embryonic fibroblast cells (MEFs) into iPSCs. RIP3 was found to be upregulated in iPSCs compared to MEFs. Deletion of RIP3 dramatically suppressed the reprogramming of iPSCs (~82%). RNA-seq analysis and qRT-PCR showed that RIP3 KO MEFs expressed lower levels of genes that control cell cycle progression and cell division and higher levels of extracellular matrix-regulating genes. The growth rate of RIP3 KO MEFs was significantly slower than WT MEFs. These findings can partially explain the inhibitory effects of RIP3 deletion on iPSCs generation and show for the first time that the necroptosis kinase RIP3 plays an important role in iPSC reprogramming. In contrast to RIP3, the kinase and scaffolding functions of RIPK1 appeared to have distinct effects on reprogramming.
William C Engeland, Logan Massman, Lauren Miller, Sining Leng, Emanuele Pignatti, Lorena Pantano, Diana L Carlone, Paulo Kofuji, and David T Breault. 2019. “Sex Differences in Adrenal Bmal1 Deletion-Induced Augmentation of Glucocorticoid Responses to Stress and ACTH in Mice.” Endocrinology, 160, 10, Pp. 2215-2229.Abstract
The circadian glucocorticoid (GC) rhythm is dependent on a molecular clock in the suprachiasmatic nucleus (SCN) and an adrenal clock that is synchronized by the SCN. To determine whether the adrenal clock modulates GC responses to stress, experiments used female and male Cyp11A1Cre/+::Bmal1Fl/Fl knockout [side-chain cleavage (SCC)-KO] mice, in which the core clock gene, Bmal1, is deleted in all steroidogenic tissues, including the adrenal cortex. Following restraint stress, female and male SCC-KO mice demonstrate augmented plasma corticosterone but not plasma ACTH. In contrast, following submaximal scruff stress, plasma corticosterone was elevated only in female SCC-KO mice. Adrenal sensitivity to ACTH was measured in vitro using acutely dispersed adrenocortical cells. Maximal corticosterone responses to ACTH were elevated in cells from female KO mice without affecting the EC50 response. Neither the maximum nor the EC50 response to ACTH was affected in male cells, indicating that female SCC-KO mice show a stronger adrenal phenotype. Parallel experiments were conducted using female Cyp11B2 (Aldosterone Synthase)Cre/+::Bmal1Fl/Fl mice and adrenal cortex-specific Bmal1-null (Ad-KO) mice. Plasma corticosterone was increased in Ad-KO mice following restraint or scruff stress, and in vitro responses to ACTH were elevated in adrenal cells from Ad-KO mice, replicating data from female SCC-KO mice. Gene analysis showed increased expression of adrenal genes in female SCC-KO mice involved in cell cycle control, cell adhesion-extracellular matrix interaction, and ligand receptor activity that could promote steroid production. These observations underscore a role for adrenal Bmal1 as an attenuator of steroid secretion that is most prominent in female mice.
Maria Mavrikaki, Lorena Pantano, David Potter, Maximilian A Rogers-Grazado, Eleni Anastasiadou, Frank J Slack, Sami S Amr, Kerry J Ressler, Nikolaos P Daskalakis, and Elena Chartoff. 2019. “Sex-Dependent Changes in miRNA Expression in the Bed Nucleus of the Stria Terminalis Following Stress.” Front Mol Neurosci, 12, Pp. 236.Abstract
Anxiety disorders disproportionately affect women compared to men, which may arise from sex differences in stress responses. MiRNAs are small non-coding RNAs known to regulate gene expression through actions on mRNAs. MiRNAs are regulated, in part, by factors such as stress and gonadal sex, and they have been implicated in the pathophysiology of multiple psychiatric disorders. Here, we assessed putative sex differences in miRNA expression in the bed nucleus of the stria terminalis (BNST) - a sexually dimorphic brain region implicated in anxiety - of adult male and female rats that had been exposed to social isolation (SI) stress throughout adolescence. To assess the translational utility of our results, we assessed if childhood trauma in humans resulted in changes in blood miRNA expression that are similar to those observed in rats. Male and female Sprague-Dawley rats underwent SI during adolescence or remained group housed (GH) and were tested for anxiety-like behavior in the elevated plus maze as adults. Small RNA sequencing was performed on tissue extracted from the BNST. Furthermore, we re-analyzed an already available small RNA sequencing data set from the Grady Trauma Project (GTP) from men and women to identify circulating miRNAs that are associated with childhood trauma exposure. Our results indicated that there were greater anxiogenic-like effects and changes in BNST miRNA expression in SI versus GH females compared to SI versus GH males. In addition, we found nine miRNAs that were regulated in both the BNST from SI compared to GH rats and in blood samples from humans exposed to childhood trauma. These studies emphasize the utility of rodent models in studying neurobiological mechanisms underlying psychiatric disorders and suggest that rodent models could be used to identify novel sex-specific pharmacotherapies for anxiety disorders.
Kathleen Hanlon, Alex Thompson, Lorena Pantano, John N Hutchinson, Arshed Al-Obeidi, Shu Wang, Meghan Bliss-Moreau, Jennifer Helble, Gabriela Alexe, Kimberly Stegmaier, Daniel E Bauer, and Ben A Croker. 2019. “Single-cell cloning of human T-cell lines reveals clonal variation in cell death responses to chemotherapeutics.” Cancer Genet, 237, Pp. 69-77.Abstract
Genetic modification of human leukemic cell lines using CRISPR-Cas9 has become a staple of gene-function studies. Single-cell cloning of modified cells is frequently used to facilitate studies of gene function. Inherent in this approach is an assumption that the genetic drift, amplified in some cell lines by mutations in DNA replication and repair machinery, as well as non-genetic factors will not introduce significant levels of experimental cellular heterogeneity in clones derived from parental populations. In this study, we characterize the variation in cell death of fifty clonal cell lines generated from human Jurkat and MOLT-4 T-cells edited by CRISPR-Cas9. We demonstrate a wide distribution of sensitivity to chemotherapeutics between non-edited clonal human leukemia T-cell lines, and also following CRISPR-Cas9 editing at the NLRP1 locus, or following transfection with non-targeting sgRNA controls. The cell death sensitivity profile of clonal cell lines was consistent across experiments and failed to revert to the non-clonal parental phenotype. Whole genome sequencing of two clonal cell lines edited by CRISPR-Cas9 revealed unique and shared genetic variants, which had minimal read support in the non-clonal parental population and were not suspected CRISPR-Cas9 off-target effects. These variants included genes related to cell death and drug metabolism. The variation in cell death phenotype of clonal populations of human T-cell lines may be a consequence of T-cell line genetic instability, and to a lesser extent clonal heterogeneity in the parental population or CRISPR-Cas9 off-target effects not predicted by current models. This work highlights the importance of genetic variation between clonal T-cell lines in the design, conduct, and analysis of experiments to investigate gene function after single-cell cloning.

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