Life Sciences Commons^™

Genetic Modification Of Human Mesenchymal Stem Cells Helps To Reduce Adiposity And Improve Glucose Tolerance In An Obese Diabetic Mouse Model., Sabyasachi Sen, Cleyton C Domingues, Carol Rouphael, Cyril Chou, Chul Kim, Nagendra Yadava

Medicine Faculty Publications

INTRODUCTION: Human mesenchymal stem cells (MSCs) are multipotent cells that can differentiate into fat, muscle, bone and cartilage cells. Exposure of subcutaneous abdominal adipose tissue derived AD-MSCs to high glucose (HG) leads to superoxide accumulation and up-regulation of inflammatory molecules. Our aim was to inquire how HG exposure affects MSCs differentiation and whether the mechanism is reversible.

METHODS: We exposed human adipose tissue derived MSCs to HG (25 mM) and compared it to normal glucose (NG, 5.5 mM) exposed cells at 7, 10 and 14 days. We examined mitochondrial superoxide accumulation (Mitosox-Red), cellular oxygen consumption rate (OCR, Seahorse) and gene …

A Mitochondria-Anchored Isoform Of The Actin-Nucleating Spire Protein Regulates Mitochondrial Division, Uri Manor, Sadie Bartholomew, Gonen Golani, Eric Christenson, Michael Kozlov, Henry Higgs, James Spudich, Jennifer Lippincott-Schwartz

Dartmouth Scholarship

Mitochondrial division, essential for survival in mammals, is enhanced by an inter-organellar process involving ER tubules encircling and constricting mitochondria. The force for constriction is thought to involve actin polymerization by the ER-anchored isoform of the formin protein inverted formin 2 (INF2). Unknown is the mechanism triggering INF2-mediated actin polymerization at ER-mitochondria intersections. We show that a novel isoform of the formin-binding, actin-nucleating protein Spire, Spire1C, localizes to mitochondria and directly links mitochondria to the actin cytoskeleton and the ER. Spire1C binds INF2 and promotes actin assembly on mitochondrial surfaces. Disrupting either Spire1C actin- or formin-binding activities reduces mitochondrial constriction …

Crosstalk Between Brca-Fanconi Anemia And Mismatch Repair Pathways Prevents Msh2-Dependent Aberrant Dna Damage Responses, Min Peng, Jenny X. Xie, Anna J. Ucher, Janet Stavnezer, Sharon B. Cantor

Janet M. Stavnezer

Several proteins in the BRCA-Fanconi anemia (FA) pathway, such as FANCJ, BRCA1, and FANCD2, interact with mismatch repair (MMR) pathway factors, but the significance of this link remains unknown. Unlike the BRCA-FA pathway, the MMR pathway is not essential for cells to survive toxic DNA interstrand crosslinks (ICLs), although MMR proteins bind ICLs and other DNA structures that form at stalled replication forks. We hypothesized that MMR proteins corrupt ICL repair in cells that lack crosstalk between BRCA-FA and MMR pathways. Here, we show that ICL sensitivity of cells lacking the interaction between FANCJ and the MMR protein MLH1 is …

Selenoprotein P Influences Colitis-Induced Tumorigenesis By Mediating Stemness And Oxidative Damage., C. W. Barrett, V. K. Reddy, S. P. Short, A. K. Motley, M. K. Lintel, A. M. Bradley, T. Freeman, J. Vallance, W. Ning, B. Parang, Shenika Poindexter Toliver

Faculty and Staff Publications

Patients with inflammatory bowel disease are at increased risk for colon cancer due to augmented oxidative stress. These patients also have compromised antioxidant defenses as the result of nutritional deficiencies. The micronutrient selenium is essential for selenoprotein production and is transported from the liver to target tissues via selenoprotein P (SEPP1). Target tissues also produce SEPP1, which is thought to possess an endogenous antioxidant function. Here, we have shown that mice with Sepp1 haploinsufficiency or mutations that disrupt either the selenium transport or the enzymatic domain of SEPP1 exhibit increased colitis-associated carcinogenesis as the result of increased genomic instability and …

Cytoskeletal Dynamics: A View From The Membrane, Magdalena Bezanilla, Amy S. Gladfelter, David R. Kovar, Wei-Lih Lee

Dartmouth Scholarship

Many aspects of cytoskeletal assembly and dynamics can be recapitulated in vitro; yet, how the cytoskeleton integrates signals in vivo across cellular membranes is far less understood. Recent work has demonstrated that the membrane alone, or through membrane-associated proteins, can effect dynamic changes to the cytoskeleton, thereby impacting cell physiology. Having identified mechanistic links between membranes and the actin, microtubule, and septin cytoskeletons, these studies highlight the membrane’s central role in coordinating these cytoskeletal systems to carry out essential processes, such as endocytosis, spindle positioning, and cellular compartmentalization.

The Nuclear Factor Of Activated T Cells (Nfat) Transcription Factor Nfatp (Nfatc2) Is A Repressor Of Chondrogenesis, Ann M. Ranger, Louis C. Gerstenfeld, Jinxi Wang, Tamiyo Kon, Hyunsu Bae, Ellen M. Gravallese, Melvin J. Glimcher, Laurie H. Glimcher

Ellen M. Gravallese

Nuclear factor of activated T cells (NFAT) transcription factors regulate gene expression in lymphocytes and control cardiac valve formation. Here, we report that NFATp regulates chondrogenesis in the adult animal. In mice lacking NFATp, resident cells in the extraarticular connective tissues spontaneously differentiate to cartilage. These cartilage cells progressively differentiate and the tissue undergoes endochondral ossification, recapitulating the development of endochondral bone. Proliferation of already existing articular cartilage cells also occurs in some older animals. At both sites, neoplastic changes in the cartilage cells occur. Consistent with these data, NFATp expression is regulated in mesenchymal stem cells induced to differentiate …

A Lipopolysaccharide-Induced Dna-Binding Protein For A Class Ii Gene In B Cells Is Distinct From Nf-Kappa B, Ellen M. Gravallese, Mark R. Boothby, Cynthia M. Smas, Laurie H. Glimcher

Ellen M. Gravallese

Class II (Ia) major histocompatibility complex molecules are cell surface proteins normally expressed by a limited subset of cells of the immune system. These molecules regulate the activation of T cells and are required for the presentation of antigens and the initiation of immune responses. The expression of Ia in B cells is determined by both the developmental stage of the B cell and by certain external stimuli. It has been demonstrated previously that treatment of B cells with lipopolysaccharide (LPS) results in increased surface expression of Ia protein. However, we have confirmed that LPS treatment results in a significant …

Pharmaceutical Integrated Stress Response Enhancement Protects Oligodendrocytes And Provides A Potential Multiple Sclerosis Therapeutic., Sharon W Way, Joseph R Podojil, Benjamin L Clayton, Anita Zaremba, Tassie L Collins, Rejani B Kunjamma, Andrew P Robinson, Pedro Brugarolas, Robert H. Miller, Stephen D Miller, Brian Popko

Anatomy and Regenerative Biology Faculty Publications

Oligodendrocyte death contributes to the pathogenesis of the inflammatory demyelinating disease multiple sclerosis (MS). Nevertheless, current MS therapies are mainly immunomodulatory and have demonstrated limited ability to inhibit MS progression. Protection of oligodendrocytes is therefore a desirable strategy for alleviating disease. Here we demonstrate that enhancement of the integrated stress response using the FDA-approved drug guanabenz increases oligodendrocyte survival in culture and prevents hypomyelination in cerebellar explants in the presence of interferon-γ, a pro-inflammatory cytokine implicated in MS pathogenesis. In vivo, guanabenz treatment protects against oligodendrocyte loss caused by CNS-specific expression of interferon-γ. In a mouse model of MS, experimental …