Medicine and Health Sciences Commons^™

Functional Characterization Of Uhrf1 Variants In Facilitating Dna Methylation, Bigang Liu, Kaila Nayvelt, Swanand Hardikar, Kimie Kondo, Marcos R Estecio, Xiaodong Cheng, Taiping Chen

The Brown Foundation: Institute of Molecular Medicine

Ubiquitin-like with plant homeodomain (PHD) and really interesting new gene (RING) finger domains 1 (UHRF1) is essential for DNA methylation inheritance. However, the functional impacts of several natural and engineered UHRF1 variants are either insufficiently characterized or obscured by conflicting results, with some discrepancies likely stemming from cellular toxicity and adaptive responses induced by DNA methylation changes. In this study, we utilized mouse embryonic stem cells (mESCs)-which uniquely tolerate the complete loss of DNA methylation-to evaluate the functional consequences of clinical mutations, isoform variation, and epitope tagging. Using rescue experiments in Uhrf1-deficient mESCs, we characterized two UHRF1 mutations identified in …

Kras G12c And Kras G12d Respond To Lipid Metabolism In An Allele-Specific Manner, Neha Arora, Hong Liang, Walaa Kattan, Wantong Yao, Haoqiang Ying, Junchen Liu, Yong Zhou

Faculty, Staff and Student Publications

KRAS mutated at hotspots G12, G13, and Q61 possess profound allele-specific oncogenesis. Signaling of KRAS mutants is mostly compartmentalized to the proteolipid nanoclusters on the plasma membrane (PM), illustrating critical roles of spatiotemporal organization in KRAS cancer signaling. The activated GTP-bound KRAS molecules, including the wild type and mutants, have been traditionally thought to favor similar lipids. We recently reported distinct lipid sensing capabilities of different KRAS mutants, especially with KRASG12D favoring unsaturated lipids and KRASG12C gaining additional enrichment of saturated lipids. As such, KRAS mutants may respond to lipid acyl chain remodeling in an allele-specific manner. Lysophosphatidylcholine acyltransferase 1 …

Erk-Mediated Phosphorylation Of Yap Defines A Noncanonical Fgf Signaling Mechanism In Stem Cells, Xiaolei Zhao, Shannon Erhardt, Li Tang, Xiaotong Chen, Stephen M Farmer, Zixiu Cheng, Wen Chen, Ella Ziyuan Lu, Kihan Sung, Chang-Ru Tsai, Mingjie Zheng, Sheng Zhang, Yang Liu, Jianxin Wang, Min Li, James F Martin, Jun Wang

Faculty, Staff and Student Publications

While Fgf and Hippo-Yap signaling are fundamental for proper development, homeostasis, and disease, their crosstalk remains largely unknown. Here, we identified that Yap and Taz, canonical Hippo effectors, function as noncanonical effectors of Fgf signaling to maintain the proper function of neural crest (NC) lineages. NC cells are a multipotent stem cell population during vertebrate embryogenesis that contribute to numerous structures and diverse cell lineages, including craniofacial and cardiac tissues, neurons, and suture mesenchymal cells (SMCs), a specified cell population required for cranial bone growth and repair. We observed that activation of Fgf signaling in NC cells and NC-derived SMCs …

Statistics Of Natural Scenes Shape Contextual Modulation In The Visual Cortex, Jiakun Fu, Suhas Shrinivasan, Luca Baroni, Zhuokun Ding, Paul G Fahey, Paweł A Pierzchlewicz, Nikos Karantzas, Kayla Ponder, Rachel Froebe, Lydia Ntanavara, Taliah Muhammad, Konstantin F Willeke, Eric Wang, Zhiwei Ding, Dat Tran, Stelios Papadopoulos, Saumil Patel, Jacob Reimer, Alexander S Ecker, Xaq Pitkow, Jan Antolik, Fabian H Sinz, Ralf M Haefner, Andreas S Tolias, Katrin Franke

Faculty, Staff and Students Publications

Vision is context dependent, with neuronal responses shaped not only by local features but also by surrounding visual input. While classical studies, using grating stimuli, show that iso-oriented surrounds suppress responses more than orthogonal surrounds, the role of contextual modulation under natural stimulus conditions remains less clear. Using recordings from mouse primary visual cortex (V1), we trained convolutional neural network models to predict neuronal responses to natural images and synthesized surround stimuli that selectively suppressed or facilitated responses to optimal center inputs. In vivo experiments confirmed these predictions. Facilitatory surrounds resembled naturalistic continuations of the optimal center stimulus, consistent with …

Reciprocal Compensation Of Caspase-2 And P53 Regulates The Dna Damage Response In Hct116 Colon Cancer Cells, Karla E Lopez, Leslie Bandera, Luiza E Coutinho, Karen Zúñiga, Sarah Wright, Lisa Bouchier-Hayes

Faculty, Staff and Students Publications

Caspase-2 has positive and negative effects on tumor growth in different cancer models. The mechanisms determining these dual outcomes of caspase-2 activation are unclear underscoring the need to assess caspase-2 function in different cell types. We report that high caspase-2 expression is associated with lower survival in patients with colon cancer and increased tumor size in HCT116 colon cancer xenografts. We investigated the interplay between caspase-2 and p53 in regulating the proliferation of these cells. While neither of these proteins had much of an effect on cell cycle arrest on their own, deficiency in both caspase-2 and p53 led to …

Laser Interstitial Thermal Therapy Enhances Bidirectional Blood-Brain Barrier Permeability In Glioblastoma, Ryan T Cleary, Yiwei Fu, David Giles, Jinyun Yuan, Diogo P Moniz Garcia, Danny Palmer, Rowland H Han, Timothy Woodiwiss, Alicia B Yang, Dimitrios Mathios, Hong Chen, Albert H Kim

2020-Current year OA Pubs

BACKGROUND: Laser interstitial thermal therapy (LITT) is a minimally invasive treatment for glioblastoma that increases blood-brain barrier (BBB) permeability. However, the mechanisms and spatiotemporal features of this effect remain unclear. It is also unknown whether LITT promotes release of circulating tumor DNA (ctDNA).

METHODS: Using our previously developed LITT mouse model, we employed single-cell RNA-sequencing (scRNA-seq) to investigate gene expression changes in endothelial cells following LITT in the naive mouse brain. Brains were also harvested at multiple time points to assess LITT effects on tight junction (TJ) integrity and transcytosis via immunofluorescence and transmission electron microscopy. Human glioblastoma tissues were …

Chemotherapeutic Induction Of Cytosolic Single-Stranded Dna Accumulation Sensitizes Triple-Negative Breast Cancer To Immunotherapy, Yong Du, Li Yang, Hui Dai, Jianli Zhou, Zhicheng Zhou, Ruoxi Yuan, Rui Ye, Anh Thai Quynh Nguyen, Kishor Bhatia, Shiaw-Yih Lin

Faculty, Staff and Students Publications

Background: Despite the widespread adoption of chemoimmunotherapy in triple-negative breast cancer (TNBC), the mechanisms by which cytotoxic chemotherapy engages antitumor immunity remain poorly defined. Identifying tumor-intrinsic immunogenic programs that predict and enhance responsiveness to immune checkpoint blockade (ICB) is therefore of critical clinical importance.

Methods: Transcriptomic signatures of TREX1 deficiency were generated from CRISPR-engineered TNBC models and applied to multiple independent TNBC cohorts treated with chemoimmunotherapy. Cytosolic single-stranded DNA (ssDNA) accumulation was quantified using a flow cytometry-based assay to functionally screen chemotherapeutic agents. Immune activation and therapeutic efficacy were evaluated using in vitro assays, syngeneic mouse tumor models, flow cytometry, …

Folr1-Targeted Actinium-225-Based Alpha-Particle Therapy Eliminates Ovarian Cancer, Neetu Singh, Esther Need, Ayden Berndt, Matthew Goff, Lydia J. Wilson, Firas Mourtada, Feng Guo, Tara Mastren, Taslim Al-Hilal, Anil K. Sood, Amit Maity, Scott C. Miller, Satoshi Minoshima, Shreya Goel, Sixiang Shi

Department of Radiation Oncology Faculty Papers

Despite the advancement in therapies, ovarian cancer treatment is challenging because of poor prognosis and high relapse associated with acquired resistance. Emerging targeted alpha particles, particularly actinium-225 (225Ac), for treating refractory cancers have opened avenues for improved therapeutic options. Here, we describe a successful example of folate receptor 1 (FOLR1)–targeted 225Ac alpha-particle therapy for treatment of ovarian cancer. Longitudinal positron emission tomography imaging demonstrated high tumor-specific uptake of αFOLR1 (anti-FOLR1 antibody) in SKOV3 xenografts. FOLR1-targeted 225Ac demonstrated high therapeutic efficacy, achieving marked tumor regression, 80% survival, and 40% complete tumor elimination. The therapy resulted in tumor-specific double-stranded DNA damage, and …

Elevated Phagocytic Capacity Directs Innate Spinal Cord Repair, Dana Klatt Shaw, Vishnu Muraleedharan Saraswathy, Anthony R Mcadow, Lili Zhou, Dongkook Park, Ridim Mote, Amulya Saini, Ashley J Douthitt, Katerina Stepankova, Brittney Unverzagt, Cédric G Geoffroy, Aaron N Johnson, Mayssa H Mokalled

2020-Current year OA Pubs

Immune cells elicit a continuum of transcriptional states after spinal cord injury (SCI). In mammals, inefficient debris clearance and chronic inflammation impede recovery and overshadow pro-regenerative immune functions. We found that zebrafish SCI elicits transient immune activation and efficient debris clearance. Transcriptomics and genetic ablation showed zebrafish macrophages are highly phagocytic and required for regeneration. Comparisons between zebrafish and mammalian macrophages identified transcription and immune response regulator (tcim) as an immune-enriched regenerative gene. Deletion of zebrafish tcim impairs phagocytosis and regeneration and activates a pro-inflammatory signature in leukocytes. Tcim expression in zebrafish and mouse macrophages establishes its conserved roles by …

Microglial Swell1 Deficiency Drives Male-Specific Seizure Vulnerability But Paradoxical Neuroprotection Through Impaired Phagocytosis, Abhijeet S Barath, Aastha Dheer, Laura Montier, Mekenzie M Peshoff, Emily Dale, Flavia Goche, Thanh Thanh Le Nguyen, Mastura Akter, Fangfang Qi, Dimitrios Kleidonas, Lauren Harris, Sarah A Jewanee, Anthony D Umpierre, Dale B Bosco, Koichiro Haruwaka, Rajan Sah, Long-Jun Wu, Rongzhuo Hua, Tejaswani Datla

The Brown Foundation: Institute of Molecular Medicine

The discovery of genes encoding the volume-regulated anion channel (VRAC) has enabled detailed exploration of its cell type-specific roles in the brain. LRRC8A (SWELL1) is the essential VRAC subunit. We observed seizure-induced, subunit-specific changes in microglial VRAC expression and investigated its function using conditional KO (cKO) of LRRC8A in microglia. SWELL1 cKO mice exhibited a male-specific increase in kainate-induced seizure severity, yet showed paradoxical neuroprotection against seizure-associated neuronal loss. Mechanistically, SWELL1 deletion led to a cell-autonomous reduction in microglial density and decreased release of VRAC-permeable neuroactive metabolites, including taurine, GABA, and glutamate in culture. Additionally, impaired phagocytic kinetics and reduced …

Bottlebrush Polymer Conjugates For Enhanced Antisense Oligonucleotide Therapy In Myotonic Dystrophy Type 1, Yao Li, Gyu Seong Heo, Yongjian Liu, Et Al.

2020-Current year OA Pubs

Oligonucleotides are a promising class of genetic medicine for myotonic dystrophy type 1 (DM1), the most common adult-onset muscular dystrophy. However, poor muscle distribution of nucleic acid drugs following systemic administration has hindered drug development, and no curative treatment currently exists. DM1 pathology requires drug localization to the nucleus, where pathogenic mutant RNA is sequestered, posing additional challenges after cellular internalization regarding endosomal escape and nuclear uptake. Here, we show that a locked nucleic acid oligonucleotide targeting mutant CUG repeat RNA tracts, conjugated to a bottlebrush polymer, exhibits improved muscle distribution and potent correction of DM1-associated splicing dysregulation in a …

Neddylation Maintains Oocyte Quality By Stabilizing Mitochondrial Transcription, Avery A Ahmed, Tessa E Steenwinkel, Bethany K Patton, Peixin Jiang, Matthew D Meyer, Jaspreet K Rishi, Mei Leng, Alexander B Saltzman, Elizabeth S Anaya, Momal Sharif, Laurie J Mckenzie, Laura Detti, Anna Malovannaya, Sean M Hartig, Stephanie A Pangas

Faculty, Staff and Students Publications

Age-related decline in oocyte quality increases the risk of infertility, miscarriage, and birth defects. Mitochondrial dysfunction is a key contributor to this decline. Here, we report that oocyte-specific deletion of Uba3, which encodes the catalytic subunit of the E1 NEDDylation-activating complex, causes sterility in mice. Fully grown, germinal vesicle–stage Uba3 conditional knockout oocytes exhibit mitochondrial dysfunction, including elevated reactive oxygen species, impaired oxidative phosphorylation, and depletion of mitochondrially encoded RNA transcripts. Proteomic analysis identified alterations in mitochondrial-associated proteins, including enrichment of mitochondrial matrix and respiratory chain components and reduced abundance of electron transport chain complexes. These defects were associated …

Intrathecal (G4c2)149 Delivery In C9orf72-Deficient Mice Yields Mild Motor Dysfunction And Als/Ftd Pathological Hallmarks, Katelyn Russell, Amelia Shahrabi, Suleyman Akerman, Matthew D. Byrne, Jeffrey Rothstein, Davide Trotti, Brigid Jensen, Aaron Haeusler

Farber Institute for Neuroscience Faculty Papers

A repeat expansion in C9ORF72 is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), yet existing mouse models incompletely engage spinal regions implicated in disease. Here, an adeno-associated virus encoding (G4C2)149 repeats was delivered via neonatal intrathecal injection, achieving widespread CNS expression with robust spinal cord targeting. This approach was applied to mice with graded loss of endogenous C9orf72 to interrogate both gain- and loss-of-function mechanisms. Longitudinal motor, behavioral, and pathological analyses revealed that repeat expression primarily drives mild, progressive muscle weakness, whereas coordination deficits were largely genotype dependent. Subtle gait abnormalities and hyperactivity …

Hp1bp3 Loss Links Chromatin Reorganization To Metabolic Vulnerability In Glioma, Brittney Lozzi, Taylor A Gatesman, Pushan Dasgupta, Debosmita Sardar, Yeunjung Ko, Chenyu Mao, Hsiao-Chi Chen, Rachel N Curry, Dongjoo Choi, Carrie A Mohila, Melissa L Bondy, Ganesh Rao, Marco Gallo, Sameer Agnihotri, Benjamin Deneen

Duncan NRI Faculty and Staff Publications

High-grade gliomas (HGGs) are aggressive brain tumors with poor prognosis, driven in part by metabolic and epigenetic adaptations. Methionine metabolism supports HGG growth by supplying S-adenosylmethionine for methylation reactions, yet how nutrient availability influences chromatin organization in HGG remains incompletely understood. Using an immunocompetent mouse model of HGG, we found that dietary methionine restriction reduced tumor proliferation, extended survival, and induced partial nuclear inversion. We identified Hp1bp3 as a key regulator of tumor growth that functions by interacting with nuclear tethering proteins to mediate chromatin reorganization. Loss of Hp1bp3 results in the upregulation of histone demethylases leading to selective depletion …

Broadly Reactive Human Monoclonal Antibodies Targeting Influenza A Nucleoprotein Lack Protective Activity In Vivo, Walter N Harrington, David C Brice, Aaron J Schmitz, Jackson S Turner, Rafael Brent, Philip A Mudd, Ali H Ellebedy, Richard J Webby

2020-Current year OA Pubs

The antibody response to influenza virus infection targets numerous viral proteins, with those specific for the hemagglutinin (HA) and neuraminidase (NA) surface glycoproteins being the most extensively studied. Antibodies to HA and NA function as independent immune correlates of protection and form the basis of most vaccine approaches. In contrast, the contribution of antibodies to other viral proteins such as the nucleoprotein (NP) remains unclear, and existing studies have reached conflicting conclusions. In this work, we examined three human monoclonal NP antibodies isolated from plasmablasts of two individuals naturally infected with influenza A virus (IAV) during the 2018-2019 influenza season. …

Gpr182 Is A Lipoprotein Receptor For Dietary Fat Absorption, Zhiwei Sun, Gwendalyn J. Randolph, Et Al.

2020-Current year OA Pubs

The lymphatic system plays a central role in lipid absorption by transporting triglyceride-rich particles called chylomicrons (CMs) from the small intestine to the systemic circulation. However, the molecular mechanism by which CMs get into the intestinal lymphatics is unknown. Here, we demonstrated that GPR182, an atypical chemokine receptor in lymphatic endothelial cells, mediates dietary fat absorption. GPR182-KO mice exhibited a selective increase in circulating high-density lipoproteins and are resistant to diet-induced obesity. GPR182 ablation in mice led to poor lipid absorption and thereby a delay in growth during development. GPR182 broadly interacted with and transported lipoproteins. Transmission electron microscopy analysis …

The N-Terminus Of Apolipoprotein B Mediates The Interaction Of Atherogenic Lipoproteins With Endothelial Cells, Ainara G. Cabodevilla, Nicholas O. Davidson, Et Al.

2020-Current year OA Pubs

Apolipoprotein B-containing (APOB-containing) lipoproteins contribute to atherosclerosis by entering the arterial wall through the endothelial cell (EC) surface receptors scavenger receptor-BI (SR-BI) and activin receptor-like kinase 1 (ALK1). We used N-terminal fragments of APOB, molecular modeling, and site-directed mutagenesis to identify and block the binding of chylomicrons and LDL to these receptors in cells and mice. We discovered that different APOB regions interact with SR-BI and ALK1 expressed on ECs. APOB48 lipoproteins were only internalized by SR-BI. A fragment of APOB comprising 18% of the N-terminal sequence, APOB18, reduced the uptake and transport of both chylomicrons and LDL by ECs, …

Macropinocytosis Inhibition Attenuates Profibrotic Responses In Lung Fibroblasts And Pulmonary Fibrosis Models, Ivan O Rosas, Aaron K Mcdowell-Sanchez, Santiago Sanchez, Juan D Cala-Garcia, Alan R Waich Cohen, Elisa Ruiz-Echartea, Scott A Ochsner, Daniel C Kraushaar, Lindsay J Celada, Dandan Sun, Francesca Polverino, Cristian Coarfa, Neil J Mckenna, Konstantin Tsoyi

Faculty, Staff and Students Publications

Idiopathic pulmonary fibrosis (IPF) is a devastating chronic lung disorder with limited treatment options. Macropinocytosis is one of the key cellular processes involved in nutrient consumption from the extracellular environment under stress conditions. Here, we studied the role of macropinocytosis in experimental pulmonary fibrosis models. We found that macropinocytosis is increased in human lung fibroblasts (HLFs) derived from patients with IPF. The inhibition of macropinocytosis with 5-(n-ethyl-n-isopropyl)-amiloride (EIPA) inhibited profibrotic responses in IPF-derived and TGF-β1-stimulated HLFs and reduced pulmonary fibrosis in bleomycin-injured (Bleo-injured) mice. EIPA exerted its antifibrotic effects by regulating amino acid uptake, mammalian target of rapamycin complex 1 …

Single-Nucleus Profiling Reveals A Core Disease Signature And Cell Type-Specific Vulnerabilities In Early Rett Syndrome, Yan Li, Ashley G Anderson, Guantong Qi, Sih-Rong Wu, Jean-Pierre Revelli, Hu Chen, Zhandong Liu, Huda Y Zoghbi

Faculty, Staff and Students Publications

Rett syndrome (RTT) is an X-linked neurological disorder caused by MECP2 mutations, creating distinct cellular environments in females (mosaic) versus males (nonmosaic). Despite female patients representing most cases, how mosaicism contributes molecularly to RTT pathogenesis, particularly in presymptomatic stages, remains poorly understood. To address this question, we profiled hippocampal transcriptomes of young female and male RTT mice using bulk and single-nucleus RNA sequencing. We identified a core disease signature of consistently dysregulated genes only in MeCP2− cells across RTT models. Moreover, we uncovered non–cell autonomous effects exclusively in female MeCP2+ excitatory neurons, suggesting that these circuits are more vulnerable early …

In Vivo Orf Overexpression Screening Identifies Ccn4 As A Regulator Of Glioblastoma Growth Validated Across Multiple Models, Pushan Dasgupta

Faculty, Staff and Students Publications

Despite current multimodal therapies for glioblastoma (GBM), its prognosis remains grim. Thus, a tremendous need exists to identify new genetic drivers that may serve as potential therapeutic targets in glioblastoma (GBM). We describe an in vivo overexpression screening strategy to identify drivers of glioblastoma where we have leveraged TCGA datasets to conduct a functional genomics screen of prioritized open reading frames (ORFs) that are overexpressed and/or amplified in GBM. To interrogate these potential drivers within a more relevant physiological context, the screening was accomplished in vivo in an orthotopic patient-derived glioma stem-like cell (GSC) model. Among 5 positive "hits" from …

Modeling Immune Responses To Autologous And Allogeneic Human Stem Cell-Derived Islet Grafts In Vivo, Camillo Bechi Genzano, Matthew Ishahak, Enrique Eduardo Sanchez-Castro, Jeffrey R. Millman, Cory Berkland, Et Al.

2020-Current year OA Pubs

Stem cell-derived β cells offer a promising approach for type 1 diabetes (T1D) treatment. However, the processes of graft infiltration and rejection by immune cells remain poorly understood in humans. In this study, autologous or allogeneic stem cell-derived islets (SC-islets) were transplanted in human immune system mice and analyzed 14 to 18 weeks later. Imaging mass cytometry revealed unique characteristics of SC-islet grafts, including a high percentage of glucagon+ cells and the presence of cysts and CD57+ enterochromaffin cells, features not typically observed in endogenous or transplanted allogeneic primary pancreatic islets. Allogeneic SC-islet grafts exhibited heavy immune infiltration, cell proliferation, …

Notch1 Acts As A Tumor Suppressor That Induces Early Differentiation In Head And Neck Cancer, Chenfei Huang, Shhyam Moorthy, Qiuli Li, Kazi M Ahmed, Kalil Saab, Defeng Deng, Jiping Wang, Xiayu Rao, Jiexin Zhang, Yuanxin Xi, Jing Wang, Zhiyi Liu, Noriaki Tanaka, David A Wheeler, Eve Shinbrot, Rami Saade, Curtis R Pickering, Tong-Xin Xie, Adel K El-Naggar, Abdullah A Osman, Kunal Rai, Patrick A Zweidler-Mckay, John V Heymach, Lauren A Byers, Faye M Johnson, Vlad C Sandulache, Jeffrey N Myers, Pedram Yadollahi, Mitchell J Frederick

Faculty, Staff and Students Publications

Inactivating NOTCH1 mutations in head and neck squamous cell carcinoma (HNSCC) were described over a decade ago, suggesting a tumor suppressor function - unlike its oncogenic role in other tumors. Today, much debate persists regarding a putative oncogenic role in HNSCC as well, with reports that NOTCH1 signaling drives tumor growth and a cancer stem cell (CSC) phenotype. In this work, comprehensive experiments unequivocally demonstrate that NOTCH1 is a tumor suppressor in HNSCC regardless of mutation or activation status and that it reduces CSC frequency. We developed a signature of NOTCH1 activation showing the pathway is associated with very early …

Histone Deacetylase Enzyme Activity Is Not The Universal Anticancer Target Of Hdac Inhibitors, Chaitra Rai, Hang Ruan, Xue Li, Wenbo Li, Hyun-Hwan Jeong, Chengchuang Song, Panpan Liu, Yingjie Chang, Hao Fang, Udhaya Kumar S, Yuxiang Sun, M James You, Dongyin Guan, Zhandong Liu, Leng Han, Xuben Hou, Zheng Sun

Faculty, Staff and Students Publications

Histone deacetylase inhibitors (HDIs) are approved for treating hematologic cancers and are currently being evaluated in hundreds of clinical trials for various cancers and other diseases, although their mechanisms of action remain poorly understood. Here, our unbiased bioinformatics analyses found that, for most cancer types, expression levels or genetic variants of histone deacetylase (HDACs) do not consistently correlate with carcinogenesis, do not predict cancer patient survival, and do not associate with cellular responses to HDIs. Whole-genome CRISPR library screens did not identify HDACs as genes affecting cellular responses to HDIs. Overexpression of dominant-negative Class I HDACs causes similar protein hyperacetylation …

Monoclonal Antibodies Targeting Pcdh7 Inhibit Tumor Growth And Enhance Immune Responses In Kras-Mutant Non-Small Cell Lung Cancer, Nicole Novaresi, Poorva Ghosh, Shayna Thomas-Jardin, Hui Deng, Xuejun Fan, Zhiqiang Ku, Wei Xiong, Xiaorong Zhou, Jingfei Zhu, Huiyu Li, Mahesh S Padanad, Bethany Smith, Chul Ahn, John D Minna, Zhiqiang An, Ningyan Zhang, Kathryn A O'Donnell

The Brown Foundation: Institute of Molecular Medicine

We identified an important oncogenic role for protocadherin 7 (PCDH7), a cell surface protein frequently overexpressed in lung adenocarcinoma and associated with poor clinical outcome. Pcdh7 depletion reduces tumor burden and prolongs survival in KrasLSL-G12D; Tp53fl/fl mice. These findings nominate this cell surface protein as an actionable therapeutic target and highlight the therapeutic potential of PCDH7 inhibition for non–small cell lung cancer. We report the development and characterization of high-affinity anti-PCDH7 monoclonal antibodies (mAbs) that inhibit downstream mitogen-activated protein kinase (MAPK) pathway activation and suppress tumor growth in multiple mutant KRAS–driven models. A lead mAb (mAb7) sensitized tumors …

Amc-F1 Regulates Mitochondria-Autophagy Crosstalk Independent Of Nutrient Stress, Yuqin Wang, Raksha K Rao, Trung Vu, Ayano Sekine, Zhengmei Mao, Nami Mccarty

The Brown Foundation: Institute of Molecular Medicine

Mitochondria and autophagy are fundamental yet distinct regulators of cellular homeostasis. Here, we identify AMC-F1 (Autophagy-Mitochondria Coupling Factor 1; formerly TRIM44) as a central integrator of mitochondrial bioenergetics and autophagy. Using Amcf1 knockout and knock-in mouse models, we demonstrate that AMC-F1 bidirectionally regulates these pathways: its loss reduces mitochondrial respiration and autophagic flux, whereas its overexpression promotes mitochondrial elongation and increases autophagy independently of nutrient stress. Transcriptomic analyses reveal AMC-F1-dependent regulation of mitochondrial biogenesis programs that engage autophagy, involving mitochondrial respiratory chain complex genes under basal conditions and mitochondrial organization factors under starvation-induced autophagy. Although dispensable under homeostasis, this coupling …

Disease-Causing Mfn2 Mutants Impair Mitochondrial Fission Dynamics By Distinct Drp1 Dysregulation, Daniel Lagos, Pamela R. De Santiago, Nicolás Pérez-Bravo, Benjamín Cartes-Saavedra, Josefa Vial-Brizzi, Diego Troncoso-Chandía, Oliver Podmanicky, Rita Horvath, Verónica Eisner

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Mitochondria undergo fusion and fission. While DRP1 regulates fission, fusion is controlled by OPA1, MFN1, and MFN2. The balance between these processes and the crosstalk between machineries remains poorly understood. MFN2 mutations cause Charcot-Marie-Tooth disease type 2 A (CMT2A), affecting mitochondrial fusion and morphology. However, their role in fission is unclear. Using skin fibroblasts from CMT2A patients (L248H and M376V MFN2 mutations) and wild-type mouse embryonic fibroblasts expressing these variants, we studied how MFN2 mutations impact mitochondrial dynamics beyond fusion. We analyzed mitochondrial morphology and dynamics by live-cell confocal microscopy and tested fusion/fission protein levels, oxygen consumption rate (OCR), extracellular …

Loss Of Mct1 Mediated Lactate Uptake Causes Delayed Endplate Maturation And Intervertebral Disc Degeneration, Maria Tsingas, Konstantinos Tsingas, Mei Smyers, Wujuan Zhang, Aaron R. Goldman, Eulisa Lawrence, John A. Collins, Makarand V. Risbud

Department of Orthopaedic Surgery Faculty Papers

During skeletal growth, it is thought that the lactate secreted by the glycolytic nucleus pulposus (NP) cells exits the intervertebral disc into circulation via endplates. Our current studies challenge this long-held notion. Mice with early postnatal, endplate, and annulus fibrosus-specific deletion of lactate importer, MCT1, exhibited disc degeneration characterized by NP cell loss and pronounced endplate structural changes. Using metabolic and transcriptomic approaches, we demonstrate that MCT1 loss inhibits endplate chondrocyte differentiation and that lactate serves both as a crucial TCA metabolite and promotes protein and histone lactylation and gene expression. These findings suggest that during skeletal growth, NP-derived lactate …

Cytosine Base Editing Of Lpa In Transgenic Mice Averts Large Deletions, Marcel A Chuecos, So Hyun Park, Madhvi M Bhakta, Usosa Too-Chiobi, Daniel Betancourth, Mingming Cao, Marco De Giorgi, Christopher J Walkey, Anjana Tiwari, Biana Godin, Julia M Assini, Donna J Palmer, Philip Ng, Michael B Boffa, Marlys L Koschinsky, Gang Bao, William R Lagor

Faculty, Staff and Students Publications

Lipoprotein(a) (Lp(a)) is a genetically determined causal risk factor for cardiovascular disease, with approximately 20% of the population exhibiting elevated levels. While there are promising drugs in development, there are currently no approved therapies specifically designed to lower Lp(a) levels. For high-risk individuals with extreme levels of Lp(a), liver-directed genome editing could be an effective one-time solution. Genome editing approaches such as CRISPR and TALENs can reduce Lp(a) in LPA-transgenic mouse models, but they frequently induce large and potentially harmful genomic deletions. Here, we report the first application of TadA-derived cytosine base editing (CBE), delivered via helper-dependent adenovirus (HDAdV) and …

Activated Dorsomedial Hypothalamic Astrocytes Regulate Feeding Behavior, Bella M. Lisenby

Honors Projects

The dorsomedial hypothalamus (DMH) region of the brain has been shown to be important for anticipatory feeding activity and play a role in restricting excessive food intake. In obese animals that overconsume calories, astrocytes within the DMH exhibit intracellular signaling changes indicative of cellular activation. Because astrocytes are known to influence neuronal function, we hypothesize that activated astrocytes regulate behavior. In the current study, we use chemogenetics combined with stereotaxic surgery to assess the contribution of astrocyte activity in the DMH towards metabolic behaviors.

Garlic-Derived Metabolite Activates Lkb1, Promotes Adipose Enampt Secretion, And Improves Age-Related Muscle Function Via Hypothalamic Signaling, Jun-Ichiro Suzuki, Kiyoshi Yoshioka, Masahiro Kurita, Takumi Sugimoto, Takahiro Eguchi, Naoki Ito, Aoi Kodama, Yasutomi Kamei, Masahiro Ohtani, Toshiaki Matsutomo, Shin-Ichiro Imai

2020-Current year OA Pubs

Garlic (Allium sativum L.) and its aged extract contain many bioactive compounds that can bring health benefits to humans. Among them, S-1-propenyl-L-cysteine (S1PC) has recently drawn significant attention in the field of nutriceutical research. However, the mechanism of its molecular action has remained poorly understood. Here, we show that S1PC significantly activates liver kinase B1 (LKB1) through enhancing its tertiary complex formation with STRAD and MO25, leading to stimulating the phosphorylation of a mammalian NAD