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Substrate Rigidity Regulates The Formation And Maintenance Of Tissues, Wei-Hui Guo, Margo Frey, Nancy Burnham, Yu-Li Wang

Nancy A. Burnham

The ability of cells to form tissues represents one of the most fundamental issues in biology. However, it is unclear what triggers cells to adhere to one another in tissues and to migrate once a piece of tissue is planted on culture surfaces. Using substrates of identical chemical composition but different flexibility, we show that this process is controlled by substrate rigidity: on stiff substrates, cells migrate away from one another and spread on surfaces, whereas on soft substrates they merge to form tissue-like structures. Similar behavior was observed not only with fibroblastic and epithelial cell lines but also explants …

Fgf2-Induced Effects On Transcriptome Associated With Regeneration Competence In Adult Human Fibroblasts, Olga Kashpur, David Lapointe, Sakthikumar Ambady, Elizabeth Ryder, Tanja Dominko

Sakthikumar Ambady

BACKGROUND: Adult human fibroblasts grown in low oxygen and with FGF2 supplementation have the capacity to tip the healing outcome of skeletal muscle injury - by favoring regeneration response in vivo over scar formation. Here, we compare the transcriptomes of control adult human dermal fibroblasts and induced regeneration-competent (iRC) fibroblasts to identify transcriptional changes that may be related to their regeneration competence. RESULTS: We identified a unique gene-expression profile that characterizes FGF2-induced iRC fibroblast phenotype. Significantly differentially expressed genes due to FGF2 treatment were identified and analyzed to determine overrepresented Gene Ontology terms. Genes belonging to extracellular matrix components, adhesion …

Rna Recognition By The Caenorhabditis Elegans Oocyte Maturation Determinant Oma-1, Ebru Kaymak, Sean Ryder

Sean P. Ryder

Maternally supplied mRNAs encode proteins that pattern early embryos in many species. In the nematode Caenorhabditis elegans, a suite of RNA-binding proteins regulates expression of maternal mRNAs during oogenesis, the oocyte to embryo transition, and early embryogenesis. To understand how these RNA-binding proteins contribute to development, it is necessary to determine how they select specific mRNA targets for regulation. OMA-1 and OMA-2 are redundant proteins required for oocyte maturation--an essential part of meiosis that prepares oocytes for fertilization. Both proteins have CCCH type tandem zinc finger RNA-binding domains. Here, we define the RNA binding specificity of OMA-1 and demonstrate that …

Developmental Decline In Neuronal Regeneration By The Progressive Change Of Two Intrinsic Timers, Yan Zou, Hui Chiu, Anna Zinovyeva, Victor Ambros, Chiou-Fen Chuang, Chieh Chang

Victor R. Ambros

Like mammalian neurons, Caenorhabditis elegans neurons lose axon regeneration ability as they age, but it is not known why. Here, we report that let-7 contributes to a developmental decline in anterior ventral microtubule (AVM) axon regeneration. In older AVM axons, let-7 inhibits regeneration by down-regulating LIN-41, an important AVM axon regeneration-promoting factor. Whereas let-7 inhibits lin-41 expression in older neurons through the lin-41 3' untranslated region, lin-41 inhibits let-7 expression in younger neurons through Argonaute ALG-1. This reciprocal inhibition ensures that axon regeneration is inhibited only in older neurons. These findings show that a let-7-lin-41 regulatory circuit, which was previously …

The Developmental Timing Regulator Hbl-1 Modulates The Dauer Formation Decision In Caenorhabditis Elegans, Xantha Karp, Victor Ambros

Victor R. Ambros

Animals developing in the wild encounter a range of environmental conditions, and so developmental mechanisms have evolved that can accommodate different environmental contingencies. Harsh environmental conditions cause Caenorhabditis elegans larvae to arrest as stress-resistant "dauer" larvae after the second larval stage (L2), thereby indefinitely postponing L3 cell fates. HBL-1 is a key transcriptional regulator of L2 vs. L3 cell fate. Through the analysis of genetic interactions between mutations of hbl-1 and of genes encoding regulators of dauer larva formation, we find that hbl-1 can also modulate the dauer formation decision in a complex manner. We propose that dynamic interactions between …

Micrornas And Developmental Timing, Victor Ambros

Victor R. Ambros

MicroRNAs regulate temporal transitions in gene expression associated with cell fate progression and differentiation throughout animal development. Genetic analysis of developmental timing in the nematode Caenorhabditis elegans identified two evolutionarily conserved microRNAs, lin-4/mir-125 and let-7, that regulate cell fate progression and differentiation in C. elegans cell lineages. MicroRNAs perform analogous developmental timing functions in other animals, including mammals. By regulating cell fate choices and transitions between pluripotency and differentiation, microRNAs help to orchestrate developmental events throughout the developing animal, and to play tissue homeostasis roles important for disease, including cancer.

Dauer Larva Quiescence Alters The Circuitry Of Microrna Pathways Regulating Cell Fate Progression In C. Elegans, Xantha Karp, Victor Ambros

Victor R. Ambros

In C. elegans larvae, the execution of stage-specific developmental events is controlled by heterochronic genes, which include those encoding a set of transcription factors and the microRNAs that regulate the timing of their expression. Under adverse environmental conditions, developing larvae enter a stress-resistant, quiescent stage called 'dauer'. Dauer larvae are characterized by the arrest of all progenitor cell lineages at a stage equivalent to the end of the second larval stage (L2). If dauer larvae encounter conditions favorable for resumption of reproductive growth, they recover and complete development normally, indicating that post-dauer larvae possess mechanisms to accommodate an indefinite period …

Micrornas: Genetically Sensitized Worms Reveal New Secrets, Victor Ambros

Victor R. Ambros

Why do many microRNA gene mutants display no evident phenotype? Multiply mutant worms that are selectively impaired in genetic regulatory network activities have been used to uncover previously unknown functions for numerous Caenorhabditis elegans microRNAs.

Delineation Of Precursors In Murine Spleen That Develop In Contact With Splenic Endothelium To Give Novel Dendritic-Like Cells., Jonathan Tan, Pravin Periasamy, Helen O'Neill

Jonathan Tan

Hematopoietic cell lineages are best described in terms of distinct progenitors with limited differentiative capacity. To distinguish cell lineages, it is necessary to define progenitors and induce their differentiation in vitro. We previously reported in vitro development of immature dendritic-like cells (DCs) in long-term cultures (LTCs) of murine spleen, and in cocultures of spleen or bone marrow (BM) over splenic endothelial cell lines derived from LTCs. Cells produced are phenotypically distinct CD11b(hi)CD11c(lo)CD8(-)MHC-II(-) cells, tentatively named L-DCs. Here we delineate L-DC progenitors as different from known DC progenitors in BM and DC precursors in spleen. The progenitor is contained within the …

Haematopoietic Stem Cells In Spleen Have Distinct Differentiative Potential For Antigen Presenting Cells., Jonathan Tan, Helen O'Neill

Jonathan Tan

Dendritic cells (DC) are known to develop from macrophage dendritic progenitors (MDP) in bone marrow (BM), which give rise to conventional (c)DC and monocytes, both dominant antigen presenting cell (APC) subsets in spleen. This laboratory has however defined a distinct dendritic-like cell subset in spleen (L-DC), which can also be derived in long-term cultures of spleen. In line with the restricted in vitro development of only L-DC in these stromal cultures, we questioned whether self-renewing HSC or progenitors exist in spleen with restricted differentiative capacity for only L-DC. Neonatal spleen and BM were compared for their ability to reconstitute mice …

Magnetic Labeling Of Bm-Msc-Derived Smcs Maintains Their Pro-Elastogenic Trophic Effects On Aneurysmal Smcs, G. Swaminathan, B. Sivaraman, I. Stoilov, Mickey Shah, Ge Zhang, R.P. Mecham, A. Ramamurthi

Ge Zhang

No abstract provided.

Pgf2Α-Associated Vascular Smooth Muscle Hypertrophy Is Ros Dependent And Involves The Activation Of Mtor, P70s6k, And Pten, Kevin Rice, Sreevani Uddemarri, Devashish Desai, Ryan Morrison, R. Harris, Eric Blough

Kevin M Rice

Prostaglandin F2α (PGF2α) increases reactive oxygen species (ROS) and induces vascular smooth muscle cell (VSMC) hypertrophy by largely unknown mechanism(s). To investigate the signaling events governing PGF2α –induced VSMC hypertrophy we examined the ability of the PGF2α analog, fluprostenol to elicit phosphorylation of Akt, the mammalian target of rapamycin (mTOR), ribosomal protein S6 kinase (p70S6k), glycogen synthase kinase-3β (GSK-3β), phosphatase and tensin homolog (PTEN), extracellular signal-regulated kinase 1/2 (ERK1/2) and Jun N-terminal kinase (JNK) in growth arrested A7r5 VSMC. Fluprostenol-induced hypertrophy was associated with increased ROS, mTOR translocation from the nucleus to the cytoplasm, along with Akt, mTOR, GSK-3β, PTEN …

Dorsoventral Boundary For Organizing Growth And Planar Polarity In The Drosophila Eye, Amit Singh, Janghoo Lim, Kwang-Wook Choi

Amit Singh

A fundamental feature of developing tissues and organs is generation of planar polarity of cells in an epithelium with respect to the body axis.

The Drosophila compound eye shows two-tier dorsoventral (DV) planar polarity. At the individual ommatidium level, the eight photoreceptors in each unit eye form a dorsoventrally asymmetric cluster. At the level of eye field, hundreds of ommatidia in the upper and lower halves of an eye are uniformly polarized dorsally or ventrally, respectively. This results in DV mirror symmetries about the equator. The uniform orientations of photoreceptor clusters over long distance in the eye field provide an …

Pgf2Α-Associated Vascular Smooth Muscle Hypertrophy Is Ros Dependent And Involves The Activation Of Mtor, P70s6k, And Pten, Kevin Rice, Sreevani Uddemarri, Devashish Desai, Ryan Morrison, R. Harris, Eric Blough

Eric Blough

Prostaglandin F2α (PGF2α) increases reactive oxygen species (ROS) and induces vascular smooth muscle cell (VSMC) hypertrophy by largely unknown mechanism(s). To investigate the signaling events governing PGF2α –induced VSMC hypertrophy we examined the ability of the PGF2α analog, fluprostenol to elicit phosphorylation of Akt, the mammalian target of rapamycin (mTOR), ribosomal protein S6 kinase (p70S6k), glycogen synthase kinase-3β (GSK-3β), phosphatase and tensin homolog (PTEN), extracellular signal-regulated kinase 1/2 (ERK1/2) and Jun N-terminal kinase (JNK) in growth arrested A7r5 VSMC. Fluprostenol-induced hypertrophy was associated with increased ROS, mTOR translocation from the nucleus to the cytoplasm, along with Akt, mTOR, GSK-3β, PTEN …

Fbf Represses The Cip/Kip Cell-Cycle Inhibitor Cki-2 To Promote Self-Renewal Of Germline Stem Cells In C. Elegans, Irene Kalchhauser, Brian Farley, Sandra Pauli, Sean Ryder, Rafal Ciosk

Sean P. Ryder

Although the decision between stem cell self-renewal and differentiation has been linked to cell-cycle modifications, our understanding of cell-cycle regulation in stem cells is very limited. Here, we report that FBF/Pumilio, a conserved RNA-binding protein, promotes self-renewal of germline stem cells by repressing CKI-2(Cip/Kip), a Cyclin E/Cdk2 inhibitor. We have previously shown that repression of CYE-1 (Cyclin E) by another RNA-binding protein, GLD-1/Quaking, promotes germ cell differentiation. Together, these findings suggest that a post-transcriptional regulatory circuit involving FBF and GLD-1 controls the self-renewal versus differentiation decision in the germline by promoting high CYE-1/CDK-2 activity in stem cells, and inhibiting CYE-1/CDK-2 …

A Mutation In The Mouse Chd2 Chromatin Remodeling Enzyme Results In A Complex Renal Phenotype, Concetta Marfella, Nils Henninger, Scott Leblanc, Namrata Krishnan, David Garlick, Lawrence Holzman, Anthony Imbalzano

Nils Henninger

BACKGROUND AND AIMS: Glomerular diseases are the third leading cause of kidney failure worldwide, behind only diabetes and hypertension. The molecular mechanisms underlying the cause of glomerular diseases are still largely unknown. The identification and characterization of new molecules associated with glomerular function should provide new insights into understanding the diverse group of glomerular diseases. The Chd2 protein belongs to a family of enzymes involved in ATP-dependent chromatin remodeling, suggesting that it likely functions as an epigenetic regulator of gene expression via the modification of chromatin structure. METHODS: In this study, we present a detailed histomorphologic characterization of mice containing …

Gamma-Sarcoglycan Is Required For The Response Of Archvillin To Mechanical Stimulation In Skeletal Muscle, Janelle Spinazzola, Tara Smith, Min Liu, Elizabeth Luna, Elisabeth Barton

Elizabeth J. Luna

Loss of gamma-sarcoglycan (gamma-SG) induces muscle degeneration and signaling defects in response to mechanical load, and its absence is common to both Duchenne and limb girdle muscular dystrophies. Growing evidence suggests that aberrant signaling contributes to the disease pathology; however, the mechanisms of gamma-SG-mediated mechanical signaling are poorly understood. To uncover gamma-SG signaling pathway components, we performed yeast two-hybrid screens and identified the muscle-specific protein archvillin as a gamma-SG and dystrophin interacting protein. Archvillin protein and message levels were significantly upregulated at the sarcolemma of murine gamma-SG-null (gsg-/-) muscle but delocalized in dystrophin-deficient mdx muscle. Similar elevation of archvillin protein …

Differential Muscle Hypertrophy Is Associated With Satellite Cell Numbers And Akt Pathway Activation Following Activin Type Iib Receptor Inhibition In Mtm1 P.R69c Mice, Michael Lawlor, Marissa Viola, Hui Meng, Rachel Edelstein, Fujun Liu, Ke Yan, Elizabeth Luna, Alexandra Lerch-Gaggl, Raymond Hoffmann, Christopher Pierson, Anna Buj-Bello, Jennifer Lachey, Scott Pearsall, Lin Yang, Cecilia Hillard, Alan Beggs

Elizabeth J. Luna

X-linked myotubular myopathy is a congenital myopathy caused by deficiency of myotubularin. Patients often present with severe perinatal weakness, requiring mechanical ventilation to prevent death from respiratory failure. We recently reported that an activin receptor type IIB inhibitor produced hypertrophy of type 2b myofibers and modest increases of strength and life span in the severely myopathic Mtm1δ4 mouse model of X-linked myotubular myopathy. We have now performed a similar study in the less severely symptomatic Mtm1 p.R69C mouse in hopes of finding greater treatment efficacy. Activin receptor type IIB inhibitor treatment of Mtm1 p.R69C animals produced behavioral and histological evidence …

Another Armed Cd4(+) T Cell Ready To Battle Hepatocellular Carcinoma, Roniel Cabrera, Gyongyi Szabo

Gyongyi Szabo

No abstract provided.

Exosome-Mediated Delivery Of Functionally Active Mirna-155 Inhibitor To Macrophages, Fatemeh Momen-Heravi, Shashi Bala, Terence Bukong, Gyongyi Szabo

Gyongyi Szabo

Exosomes, membranous nanovesicles, naturally carry bio-macromolecules and play pivotal roles in both physiological intercellular crosstalk and disease pathogenesis. Here, we showed that B cell-derived exosomes can function as vehicles to deliver exogenous miRNA-155 mimic or inhibitor into hepatocytes or macrophages, respectively. Stimulation of B cells significantly increased exosome production. Unlike in parental cells, baseline level of miRNA-155 was very low in exosomes derived from stimulated B cells. Exosomes loaded with a miRNA-155 mimic significantly increased miRNA-155 levels in primary mouse hepatocytes and the liver of miRNA-155 knockout mice. Treatment of RAW macrophages with miRNA-155 inhibitor loaded exosomes resulted in statistically …

Serum Dioxins And Polychlorinated Biphenyls Are Associated With Growth Among Russian Boys, Jane Burns, Paige Williams, Oleg Sergeyev, Susan Korrick, Mary Lee, Boris Revich, Larisa Altshul, Julie Del Prato, Olivier Humblet, Donald Patterson, Wayman Turner, Larry Needham, Mikhail Starovoytov, Russ Hauser

Mary M. Lee

OBJECTIVE: We evaluated the associations of serum dioxins and polychlorinated biphenyls (PCBs) with longitudinally assessed growth measurements among peripubertal Russian boys.

METHODS: A total of 499 boys from Chapaevsk, Russia, aged 8 to 9 years were enrolled in the study from 2003 to 2005 and were followed prospectively for 3 years. Blood samples were collected and physical examinations were conducted at entry and repeated at annual study visits. Multivariate mixed-effects regression models for repeated measures were used to examine the associations of serum dioxins and PCBs with longitudinal measurements of BMI, height, and height velocity.

RESULTS: Serum dioxin (total 2005 …

Measurement Of Mullerian Inhibiting Substance Facilitates Management Of Boys With Microphallus And Cryptorchidism, Madhusmita Misra, David Maclaughlin, Patricia Donahoe, Mary Lee

Mary M. Lee

Mullerian inhibiting substance (MIS) is a gonadal hormone expressed in a sexually dimorphic pattern. In males, serum MIS reflects Sertoli cell function and provides an estimate of seminiferous tubular integrity. We examined the role of MIS determination in the evaluation of boys with microphallus (n = 62) and/or cryptorchidism (n = 156). MIS was normal in 69.2% of boys with isolated microphallus compared with 38.1% of boys with microphallus and coexisting cryptorchidism (P < 0.05). In the cryptorchid group, MIS was normal in 46.8%, low in 24.4%, and absent in 28.8%. Normal values for age were associated with testicular tissue, whereas …

Pubertal And Adult Leydig Cell Function In Mullerian Inhibiting Substance-Deficient Mice, Xiufeng Wu, Ramamani Arumugam, Stephen Baker, Mary Lee

Mary M. Lee

Mullerian inhibiting substance (MIS) causes Mullerian duct regression during sexual differentiation and regulates postnatal Leydig cell development. MIS knockout (MIS-KO) mice with targeted deletions of MIS develop Leydig cell hyperplasia, but their circulating androgen concentrations are reportedly unaltered. We compared reproductive hormone profiles, androgen biosynthesis, and the expression of key steroidogenic and metabolic enzymes in MIS-KO and wild-type (WT) mice at puberty (36 d) and sexual maturity (60 d). In pubertal animals, basal testosterone and LH concentrations in plasma were lower in MIS-KO than WT mice, whereas human chorionic gonadotropin-stimulated testosterone concentrations were similar. In adults, basal LH, and both …

Augmented Growth Hormone (Gh) Secretory Burst Frequency And Amplitude Mediate Enhanced Gh Secretion During A Two-Day Fast In Normal Men, Mark Hartman, Johannes Veldhuis, Michael Johnson, Mary Lee, K. Alberti, Eugene Samojlik, Michael Thorner

Mary M. Lee

Serum GH concentrations are increased in fasted or malnourished human subjects. We investigated the dynamic mechanisms underlying this phenomenon in nine normal men by analyzing serum GH concentrations measured in blood obtained at 5-min intervals over 24 h on a control (fed) day and on the second day of a fast with a multiple-parameter deconvolution method to simultaneously resolve endogenous GH secretory and clearance rates. Two days of fasting induced a 5-fold increase in the 24-h endogenous GH production rate [78 +/- 12 vs. 371 +/- 57 micrograms/Lv (Lv, liter of distribution volume) or 0.24 +/- 0.038 vs. 1.1 +/- …

Developmental Expression Of A Candidate Mullerian Inhibiting Substance Type Ii Receptor, Jose Teixeira, Wei He, Paresh Shah, Nobuyuki Morikawa, Mary Lee, Elizabeth Catlin, Peter Hudson, John Wing, David Maclaughlin, Patricia Donahoe

Mary M. Lee

We have isolated a candidate Mullerian inhibiting substance (MIS) type II receptor complementary DNA from an embryonic rat urogenital ridge library and have studied its binding to MIS, its developmental pattern of expression and tissue distribution. By in situ hybridization with a full-length riboprobe, the receptor is expressed in the mesenchymal cells surrounding the Mullerian duct at embryonic days 14, 15, and 16 and in tubular and follicular structures of the rat fetal gonads. Expression of the messenger RNA was also seen in the granules cells and seminiferous tubules of pubertal gonads. Northern analysis revealed that the MIS type II …

Developmentally Regulated Polyadenylation Of Two Discrete Messenger Ribonucleic Acids For Mullerian Inhibiting Substance, Mary Lee, Richard Cate, Patricia Donahoe, Gerald Waneck

Mary M. Lee

Mullerian inhibiting substance (MIS) is a 140-kilodalton homodimeric glycoprotein that causes regression of the Mullerian ducts in male embryos, and may also have a role in both males and females in the regulation of germ cell maturation. We examined the ontogeny of MIS messenger RNA (mRNA) in rat testes from midgestation through adulthood and found two discrete MIS mRNA species that are developmentally regulated. The larger 2.0-kilobase species is abundant at embryonic day 14, then decreases in late gestation, and is barely detectable after birth. The smaller 1.8-kilobase species is first noted at embryonic day 18 and is the major …

Transient Hyperthyroidism In An Adolescent With Hydatidiform Mole, Madhusmita Misra, Lynne Levitsky, Mary Lee

Mary M. Lee

No abstract provided.

Mullerian Inhibiting Substance In Humans: Normal Levels From Infancy To Adulthood, Mary Lee, Patricia Donahoe, Tomonobu Hasegawa, Bernard Silverman, Gretchen Crist, Sharon Best, Yukihiro Hasegawa, Richard Noto, David Schoenfeld, David Maclaughlin

Mary M. Lee

Mullerian-inhibiting substance (MIS) is a gonadal hormone synthesized by Sertoli cells of the testis and granulosa cells of the ovary. To facilitate the use of MIS for the evaluation of intersex disorders and as a tumor marker in women with MIS-expressing ovarian tumors, we measured MIS in 600 serum samples from males and females. These data show that mean MIS values for males rise rapidly during the first year of life and are highest during late infancy, then gradually decline until puberty. In contrast, MIS values in females are lowest at birth and exhibit a minimal increase throughout the prepubertal …

Serum Concentrations Of Organochlorine Pesticides And Growth Among Russian Boys, Jane Burns, Paige Williams, Oleg Sergeyev, Susan Korrick, Mary Lee, Boris Revich, Larisa Altshul, Julie Del Prato, Olivier Humblet, Donald Patterson, Wayman Turner, Mikhail Starovoytov, Russ Hauser

Mary M. Lee

BACKGROUND: Limited human data suggest an association of organochlorine pesticides (OCPs) with adverse effects on children's growth. OBJECTIVE: We evaluated the associations of OCPs with longitudinally assessed growth among peripubertal boys from a Russian cohort with high environmental OCP levels. METHODS: A cohort of 499 boys enrolled in the Russian Children's Study between 2003 and 2005 at 8-9 years of age were followed prospectively for 4 years. At study entry, 350 boys had serum OCPs measured. Physical examinations were conducted at entry and annually. The longitudinal associations of serum OCPs with annual measurements of body mass index (BMI), height, and …

Mullerian Inhibiting Substance In The Diagnosis And Management Of Intersex And Gonadal Abnormalities, Michael Gustafson, Mary Lee, Lara Asmundson, David Maclaughlin, Patricia Donahoe

Mary M. Lee

Mullerian inhibiting substance (MIS), a gonadal hormone important in sexual differentiation, is high (10 to 70 ng/mL) in human male serum postnatally for several years before declining during the peripubertal period, but is undetectable in female serum until the onset of puberty. The sexually dimorphic secretion of MIS suggested possibilities for its use in several clinical settings. Thirty-one patients with intersex and gonadal anomalies from 17 institutions were therefore evaluated between 1989 and 1992 with an MIS enzyme-linked immunosorbent assay (ELISA). Serum MIS levels correlated with the presence of testicular tissue in two patients with suspected anorchia, five patients with …