bluuebunny/crossref_metadata_2025 huggingface dataset:
The Association between Epidermal Growth Factor Receptor (EGFR) Gene Polymorphisms and Lung Cancer Risk
Authors: Bashir Nabil , Ragab Entesar , Khabour Omar , Alfaqih Mahmoud , Khassawneh Basheer , Momani Jafar
Published: April 2020

Lung cancer is the leading cause of cancer death globally. The epidermal growth factor receptor (EGFR) plays an important role in cell proliferation and signaling. In this study, we examined the association between EGFR gene polymorphisms and lung cancer risk among the Jordanian population. A total of 129 patients with primary lung cancer and 129 matched healthy controls were recruited into this study. EGFR rs712829, rs712830, rs2072454, and rs11543848 single nucleotide polymorphisms (SNPs) were genotyped to test for their association with lung cancer risk. A significant association was observed between the rs712829 SNP and lung cancer risk (p < 0.05) where the GG + GT genotypes were higher in lung cancer patients when compared to controls. In addition, no association was detected between rs712830, rs2072454, and rs11543848 SNPs and lung cancer risk. When patients were stratified according to the lung cancer type, a significant association was detected between both rs712829 and rs2072454 and adenocarcinoma lung cancer (p < 0.05). Haplotype analysis of all four SNPs showed a significant association between the TCCG haplotype and both lung cancer and the adenocarcinoma subtype (p < 0.001). In conclusion, EGFR rs712829, rs2072454 SNPs, and TCCG haplotypes are associated with a risk of lung cancer among Jordanians. Since genetic associations are affected by the genetic background of populations, more studies in other Arab populations are required to confirm the present findings.

Support or Funding Information

The study was supported by funding provided by the Ministry of Higher Education—Scientific Research Fund (SRF) grant number JUST‐1‐2016.

Genotypes/Allele Pattern

Patients

Controls

p‐Value

For rs712829

GG

12 (28%)

29 (22%)

0.020

TT

4 (9%)

35 (27%)

GT

27 (63%)

65 (50%)

For rs712830

CC

41 (95%)

121 (94%)

0.670

CA

2 (5%)

8 (6%)

For rs2072454

CC

6 (14%)

15 (12%)

0.027

TT

26 (60%)

57 (44%)

CT

11 (26%)

57 (44%)

For rs11543848

AA

8 (19%)

26 (20%)

0.073

GG

2 (5%)

18 (14%)

GA

33 (77%)

85 (66%)

Note: Rs29: rs712829, Rs30: rs712830, Rs54: rs2072454 and Rs48: rs11543848.

Haplotype

Rs29

Rs30

Rs54

Rs48

Frequency

Odd Ratio (95% CI)

p‐Value

1

T

C

T

A

0.2118

1.00

—

2

G

C

T

A

0.1748

1.00 (0.31–3.24)

1

3

G

C

T

G

0.1552

0.93 (0.34–2.55)

0.9

4

T

C

T

G

0.1228

1.38 (0.32–5.96)

0.66

5

G

C

C

G

0.0953

1.08 (0.31–3.67)

0.91

6

T

C

C

A

0.0794

1.46 (0.33–6.43)

0.62

7

G

C

C

A

0.0681

0.69 (0.15–3.15)

0.63

8

T

C

C

G

0.0629

168,507 (168,498–168,517)

<0.001

9

G

A

T

G

0.0156

0.71 (0.08–6.39)

0.76

Note: Rs29: rs712829, Rs30: rs712830, Rs54: rs2072454 and Rs48: rs11543848.
The Expression of MRPL42 in Glioma and Its Prognostic Analysis
Authors: Duan Hubin , Hao Chunyan , Qiao Xiaohong , Wang Hongqin , Xue Wen , Lu Jian , Zhang Jinbao , Zhang Huaping , Zhang Ce
Published: April 2020

Objective

To determine the correlation between mitochondrial ribosomal protein MRPL42 expression levels in glioma and its association with clinicopathological parameters and prognosis.

Methods

immunohistochemistry assays were performed to explore the MRPL42 levels among diverse World Health Organization (WHO) grade of glioma, and its correlation with clinicopathological characteristics and survival prognosis of patients was also analyzed.

Results

The results of immunohistochemistry analysis indicated that the expression of MRPL42 was positively correlated with glioma WHO grade(P<0.05) and several malignant clinicopathological index including Ki67 and P53mut. Besides, Kaplan‐Meier survival analysis also illustrated that patients with high expression of MRPL42 had significantly shorter overall survival than those with low expression of MRPL42(P<0.05).

Conclusion

The expression of MRPL42 not only showed a tumor grade and clinicopathological factors‐dependent pattern, but also existed a positive correlation between them and distinguished glioma with poor prognosis, which may serve as prognostic biomarkers and potential therapeutic targets in glioma.

Support or Funding Information

• This study was supported by the National Natural Science Foundation Youth Fund (30600637), China Postdoctoral Science Foundation Grant (2019T120195), China Postdoctoral Science Foundation Grant (2014M561207), the Shanxi Province Basic Research Program ( 2010021034‐4, 201601D011119), the Shanxi Scholarship Council of China (2011‐096 and Key Projects No. 4), Department of Human Resources and Social Security of Shanxi province, The science and technology research projects of health department of Shanxi Province (2016D011119), The Teaching Reform Program of Shanxi Higher Education, The Education Reform Project of Postgraduate Students in Shanxi Province. The Project of “131” Leading Talents of Shanxi Higher Education, The Education Reform Project of Shanxi Medical University.
Comparison of respiratory tract effects of inhaled naphthalene in rats with and without co‐exposure to carbon nanoparticles
Authors: Arauz Edwin Javier , Abbott Jeffrey , Rocha Fernanda , Roberts Stephen
Published: April 2020

We have previously observed that inhalation co‐exposure of rats to carbon particles resulted in increased deposition of naphthalene in the bronchi and lungs. In order to examine whether these changes in naphthalene deposition might alter the location or severity of naphthalene toxicity within the respiratory tract, male Sprague‐Dawley rats were exposed nose‐only to naphthalene vapor (20 ppm) with or without carbon particles (5mg/m3) for 4 h. Animals exposed to particles only or to filtered room air alone (no naphthalene or particles) served as controls. Respiration was monitored during exposure by plethysmography. Forty‐eight h after exposure, rats were euthanized and brochoalveolar lavage fluid (BALF) was collected. Nasal and lung tissues were removed and prepared for histological assessment. Lymphocyte counts in BALF from animals treated with naphthalene plus particles were significantly higher than in animals treated with naphthalene or particles alone, or in controls. However, there was no increase in pro‐inflammatory cytokines or chemokines in BALF in animals co‐treated with naphthalene and particles compared with other treatment groups. Animals treated with naphthalene, with or without particles, had significant epithelial damage in the nasal cavity characterized by extensive fibrinous membrane and necrosis and loss of epithelium, as well as inflammation characterized by lymphocytes and plasma cells in the submucosa and epithelium. Particle co‐exposure did not appear to influence the severity of lesions. No nasal cavity epithelial lesions were observed in animals treated with particles only or room air alone. No significant pathology was observed in trachea, bronchioles or alveoli in any treatment group. The results of this study suggest that the increased deposition of naphthalene in lungs with particle co‐exposure observed previously is not associated with increased pulmonary toxicity, at least under the conditions of this study.
The Interplay between O‐GlcNAc And Phosphorylation on Tyrosine Hydroxylase Activity And Cathecolamine Synthesis in PC12 Cells
Authors: da Costa Rodrigues Bruno , Lucena Miguel , Rego Anna , Oliveira Isadora , Beckman Danielle , Ferreira Sergio Teixeira , de Mello Fernando Garcia , Todeschini Adriane Regina , Reis Ricardo , Dias Wagner Barbosa
Published: April 2020

About 2% to 5% of all glucose that enters the cell is directed to the Hexosamine Biosynthetic Pathway (HBP), which has glutamine fructose‐6‐phosphate aminotransferase (GFAT) as the rate‐limiting step enzyme. HBP has UDP‐N‐acetylglucosamine (UDP‐GlcNAc) as a final product, which can be used as substrate for intracellular O‐GlcNAc; a post‐translational modification (PTM) resulting from the covalent attachment of a GlcNAc to the hydroxyl groups on serine and threonine residues in proteins. This reaction is catalyzed by O‐GlcNAc transferase (OGT), and the removal reaction of this monosaccharide is made by O‐GlcNAcase (OGA). The balance of the activity of such enzymes and UDP‐GlcNAc availability will regulate the levels of O‐GlcNAcylated proteins, with an O‐GlcNAcylation, similarly to phosphorylation, highly inducible, dynamic and active in many cellular processes. Tyrosine hydroxylase (TH) is the rate‐limiting step enzyme in catecholamine synthesis, responsible for hydroxylate L‐tyrosine at meta‐position to obtain L‐DOPA, the precursor of dopamine, which has a physiological role as a neurotransmitter. There are several supports on the literature that phosphorylation on serine 40 of TH increases its activity on a dynamical way, however, the mechanism of how O‐GlcNAc plays a role on this modulation remains unknown. We showed in PC12 cells treated with the pharmacological inhibitor of OGA Thiamet G (TMG); and nerve growth factor (NGF), a compound that induces these cells in a process of neuritogenesis, that O‐GlcNAcylation acts on the control of the phosphorylation levels of serine 40 in TH, where stimulation by 28% on the increase in phosphorylation at serine 40 decreases the levels of O‐GlcNAc in 26% compared to control; while the increase of intracellular O‐GlcNAc in 19% reduces the phosphorylation at serine 40 by 16%. In addition, HPLC analysis shows that the increase of intracellular O‐GlcNAc reduces the levels of L‐DOPA and dopamine by 80%. Finally, TH’s immunoprecipitation analysis reveals that it is O‐GlcNacylated, and this PTM regulates its activity. These data suggest a cellular mechanism that integrates carbohydrate metabolism (by HBP) with the catecholamine biosynthetic pathway in a neuritogenesis process; where competition between O‐GlcNAc and phosphate at serine 40 tyrosine hydroxylase site modulates its activity, controlling the synthesis of dopamine levels in PC12 cells.

Support or Funding Information

Funding: CNPq, CAPES, FAPERJ
A time‐resolved fluorescence resonance energy transfer‐based screen for identification of a novel claudin‐4 binder that modulates the epithelial tight junction barrier
Authors: Kondoh Masuo , Watari Akihiro , Yagi Kiyohito
Published: April 2020

Claudins, a 27‐member family of proteins with four transmembrane domains each, play a pivotal role in maintaining tight junction (TJ) seals in epithelial and endothelial tissue. The C‐terminal fragment of Clostridium perfringens enterotoxin (C‐CPE) binds to claudin‐4, which is a key functional and structural component of the TJ in mucosal epithelial cells. Upon binding, C‐CPE reversibly modulates TJ seals, yielding an enhancement of the paracellular transport of solutes. However, the use of C‐CPE as an absorption enhancer is limited by the molecule’s immunogenicity and manufacturing cost. In the present study, we developed a high‐throughput screening system using Time‐Resolved Fluorescence Resonance Energy Transfer (TR‐FRET) to identify small‐molecule compounds that bind to claudin‐4. Using this system, we performed a claudin‐4 binding screen of a library containing 2642 biologically active small molecules, and identified thiostrepton as a novel claudin‐4 binder. Thiostrepton decreased the transepithelial electrical resistance and increased flux of 4‐kDa FITC‐dextran in Caco‐2 cell monolayers without cell toxicity. Immunoblotting analysis revealed that thiostrepton changed the level of claudin‐4 in the Triton‐X soluble fraction, which contains TJ components, without altering the localization of claudin‐4. Furthermore, treatment of isolated rat jejunum with thiostrepton increased absorption of 4‐kDa FITC‐dextran. The TR‐FRET‐based screening system described here is expected to be of use in identifying compounds that modulate the permeability of the intestinal epithelial cell barrier; these compounds might serve as novel absorption enhancers in the intestine.

Support or Funding Information

This study was supported in part by Grants‐in‐Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology of Japan (19H04468, 18K19400); a grant for Research on Development of New Drugs from the Japan Agency for Medical Research and Development (AMED); and grants from the Platform Project for Supporting Drug Discovery and Life Science Research (Basis for Supporting Innovative Drug Discovery and Life Science Research [BINDS]) of AMED (JP19am0101077, JP19am0101084, JP19am0101090).
Stain pleiotropy: direct regulation of arterial contractility by simvastatin
Authors: Zerin Farzana , Hasan Ahasanul , Hasan Raquibul
Published: April 2020

Long‐term use of simvastatin, an inhibitor HMG‐CoA reductase and cholesterol synthesis, has been reported to influence vascular function secondary to the reduction of cholesterol. However, direct effects of simvastatin application on fresh isolated arteries and its relevance for arterial contractility regulation are unclear. Here, we investigated direct regulation of vascular reactivity by therapeutic concentrations of simvastatin in an ex‐vivo preparation of rat thoracic aorta using a combination of wire myography, Western blotting, and arterial biotinylation techniques. Our wire myography data revealed that simvastatin stimulates reversible contraction of aorta at therapeutic concentrations (0.0001–0.1 μM), with 0.01 μM producing maximum response that is equivalent to ~60% of depolarization‐mediated aorta contraction induced by 60mM K+. Endothelium removal or co‐application of mevalonate with simvastatin did not alter simvastatin‐induced vasocontraction. In contrast, removing extracellular Ca2+ with EGTA or co‐application of nimodipine, a blocker of CaV1.2, each abolished simvastatin‐evoked contraction of aorta. Ryanodine, a blocker of ryanodine receptor‐mediated Ca2+ release from intracellular Ca2+ stores, did not alter aorta contraction by simvastatin. Arterial biotinylation data showed that CaV1.2 channel protein expression and relative cellular distribution remain unchanged by simvastatin for the time points covering duration of simvastatin application. In summary, our data suggest that simvastatin directly controls arterial smooth muscle cell [Ca2+]i and arterial contractility primarily by stimulating Ca2+ entry via CaV1.2 ion channel in arterial smooth muscle cells, which is independent of HMG‐CoA reductase inhibition by simvastatin. Our future studies will examine if simvastatin and other statins can alter arterial contractility and blood pressure in normotensive and hypertensive animals in which CaV1.2 is upregulated.

Support or Funding Information

This work was supported by a start‐up grant from the Mercer University College of Pharmacy to Dr. Raquibul Hasan
Diversity of Natural Chemicals Based on Variable Environmental Conditions: Discovery and Development
Authors: soliman sameh
Published: April 2020

Chemical ecology is the study of chemical interactions between living organisms and their environment, as consequences the organism evolved strategies in order to adapt the surrounding environment. An organism can communicate with its environment through production of chemical signals. Chemical signals can be found in all biological systems including microbes, plants, and animals. The study of chemical ecology can offer a powerful insight into these biological/chemical interactions and hence can be employed in ecologically‐based applications including medical, agriculture, and pharmaceutical industries. Chemical screening of Calligonum comosum, a plant native to the hot climate of UAE, showed that the plant developed both short‐distance (local) and long‐distance (systematic over limited sphere) phytochemicals. Local chemical was represented by phenolic idioblasts that were released in response to plant cutting. Systematic chemical was represented by toxic volatile oil containing ~50% cuminaldehyde. The plant produced the oil as defensive strategies against both pathogens invasion and herbivore attack. Cuminaldehyde has never been reported from the same plant genotype native to other climates. Furthermore, a combination of volatile oil extracted from UAE Calligonum plant and lawsone extracted from UAE Henna plant in a liposome pharmaceutical dosage form showed great synergistic antimicrobial activity with minimal toxicity. On the other hand, cuminaldeyde requires the presence of less‐polar chemical adjuvants to overcome microbial resistance. The obtained results represent chemical evolution due to climate. Generating a natural chemical library in context of logic chemical evolution of an organism with assigned biological activities will help to develop novel effective medicines.
Redox Signaling in Human Brain Vascular Smooth Muscle Cells
Authors: Rybka Vladyslava , Marcocci Lucia , Sariipek Nurefsan E. , Shults Nataliia V. , Gychka Sergiy G. , Suzuki Yuichiro
Published: April 2020

Background

Stroke is a leading cause of death in the U.S. and worldwide. Ischemic stroke is the major type of stroke, in which blood vessels in the brain become blocked. Thickening of the vascular wall narrows the lumen of the brain vessel and increases the incidence of ischemic stroke. Smooth muscle cell (SMC) growth contributes to the thickening of the vascular wall. Therapeutic strategies to inhibit and/or reverse brain vascular SMC growth, therefore, should reduce the incidence of ischemic stroke. However, the mechanism of brain vascular SMC growth is not well understood. Redox processes through the generation of reactive oxygen species (ROS) regulate cell signaling in various biological processes. The present study examined redox signaling, in particular, iron‐dependent protein carbonylation signaling in brain vascular SMCs.

Methods & Results

Treatment of cultured human brain vascular SMCs with deferoxamine (an iron chelator) resulted in a dose‐dependent reduction of cell growth induced by serum or by platelet‐derived growth factor (PDGF) as monitored by CCK8 colorimetric cell viability assay. As our laboratory previously discovered that iron‐catalyzed protein carbonylation mediates cell signaling in other cell types, we tested the effects of PDGF on protein carbonylation in human brain vascular SMCs. Treatment with PDGF promoted transient carbonylation of various proteins with a peak at 10 min. U0126, an inhibitor of the MEK/ERK pathway suppressed PDGF‐induced growth of human brain vascular SMCs and deferoxamine reduced ERK phosphorylation and activation in response to PDGF, suggesting that redox signaling occurs upstream from the ERK activation. The immunohistochemistry detection of malondialdehyde in brain tissues from human patients who died of stroke indicated the production of ROS in the vascular smooth muscle layer.

Conclusions

We demonstrate that redox signaling mediates the growth of brain vascular SMCs, opening up the possibility for targeting redox processes to improve therapeutic strategies to reduce the incidence of ischemic stroke.

Support or Funding Information

Supported by NIH
Effects of Lycopene on Growth Factor Response in Prostate Cancer Cells
Authors: Nivison Mary , VanderWilde Allegra , Balijepalli Pravita , Meier Kathryn E.
Published: April 2020

Dietary and nutritional factors are considered critical modulating factors in prostate cancer development. Epidemiological data have suggested to the idea that dietary consumption of lycopene, found in tomatoes, may prevent prostate cancer. This study examined the mechanism by which lycopene interacts with prostate cancer cells, with the goal of discovering less toxic treatment and prevention options. The hypothesis that was addressed was that lycopene interferes with growth factor‐mediated signal transduction in prostate cancer cells. The effects of lycopene on PC‐3, a human prostate cancer cell line, were analyzed using proliferation assays, immunoblot analysis, and confocal microscopy. The growth factors used were lysophosphatidic acid (LPA) and epidermal growth factor (EGF). Lycopene (10 μM) inhibited LPA and EGF‐induced proliferation of PC‐3 cells, confirming previous unpublished results. Lycopene also inhibited activation of Akt in response to LPA and EGF as assessed by immunoblotting. Confocal immunofluorescence microscopy showed that the decrease in activated Akt was most prominent in the cell nucleus. These results confirm the ability of lycopene to inhibit growth factor response in human prostate cancer cells, and suggest new directions for future studies.

Support or Funding Information

Supported by the ASPET Summer Undergraduate Research Program, College of Pharmacy and Pharmaceutical Sciences, Sue Harriet Monroe Mullen Innovative Cancer Prevention Research Fund, and the ASPET David Lehr Award.
RNA Modifications in Health and Disease
Authors: Suzuki Tsutomu
Published: April 2020

RNA molecules are frequently modified post‐transcriptionally, and these modifications are required for proper RNA functions. To date, about 150 different types of chemical modifications have been identified in various RNA molecules across all domains of life. There are still a number of novel modifications to be discovered. RNA modifications appear to confer chemical diversities to simple RNA molecules basically composed of four letters, to acquire a greater variety of biological functions. These modifications play critical roles in stability and functions of RNA molecules. We’ve been carrying out a project to identify novel RNA modifications from various sources, and reported seven modifications so far. Taking advantage of mass spectrometric analysis of RNA modifications, we systematically screened a series of knockout strains for uncharacterized genes, and identified more than 40 genes responsible for tRNA modifications, rRNA modifications as well as mRNA modification. Recently, we identified a cap‐specific adenosine methyltransferase (CAPAM) responsible for N6‐methylation of m6Am at the transcription start site of eukaryotic mRNAs.

It has been generally thought that tRNA modifications are stable and static, and their frequencies are rarely regulated. We previously reported that lack of tRNA modification causes major classes of mitochondrial diseases including MELAS and MERRF. Deficient tRNA modification results in defective protein synthesis, leading to mitochondrial dysfunction. These findings provided the first evidence of human disease caused by an RNA modification disorder. We call “RNA modopathy” as a new category of human diseases. I am going to show our recent studies on RNA modifications associated with human diseases and their dynamic regulation by sensing intracellular metabolites under physiological condition.
Structural Basis of Dystroglycan Function and the Pathogenesis of Muscular Dystrophy
Authors: Campbell Kevin P.
Published: April 2020

(DG) is a widely expressed high‐affinity extracellular matrix receptor that requires extensive glycosylation and additional post‐translational processing. In skeletal muscle, DG is part of the dystrophin‐glycoprotein complex, which establishes a continuous link between laminin‐G‐like (LG) domains of extracellular matrix‐resident proteins (laminin, agrin, and perlecan) and the cytoskeleton. Extracellular matrix proteins that contain LG domains bind to α‐DG via a novel heteropolysaccharide [‐GlcA‐β1,3‐Xyl‐α1,3‐]n called matriglycan, which is synthesized by the bifunctional enzyme known as Like‐acetylglucosaminyltransferase (LARGE). We have used a multidisciplinary approach to provide the first atomic‐level insights into the structure of a unique protein‐carbohydrate interaction that is essential for the binding of α‐DG to the extracellular matrix. We first purified LARGE and synthesized matriglycan chains of defined lengths in sufficient quantities to perform both biochemical and structural studies. Using NMR spectroscopy, we found that matriglycan bound to laminin‐α2 LG4,5 with high affinity (Kd=0.23 μM) and that this binding was calcium dependent. Next, we initiated a collaboration with Erhard Hohenester, who had previously crystallized laminin‐α2 LG4,5. We provided Dr. Hohenester with enough matriglycan to soak into crystals of LG4,5 and to produce a high‐resolution crystal structure of LG4,5 bound to matriglycan. This analysis revealed that the LG4 domain is a Ca2+‐dependent lectin with specificity for GlcA‐β1,3‐Xyl disaccharides, and that a single glucuronic acid‐β1,3‐xylose disaccharide repeat straddles a Ca2+ ion in the LG4 domain, with oxygen atoms from both sugars replacing Ca2+‐bound water molecules. This chelating binding mode is unprecedented among animal lectins and accounts for the high affinity of this protein‐carbohydrate interaction as measured by NMR. Finally, we used two novel exoglycosidases to provide direct evidence that native α‐DG contains unmodified matriglycan and numerous GlcA‐Xyl repeats. The multiple tandem repeats in matriglycan are predicted to increase the apparent affinity of the protein for LG domains by favoring rapid rebinding after dissociation. Abnormalities in the post‐translational processing of DG lead to an absence or reduction of the matriglycan modification on α‐DG, and thereby lead to various forms of muscular dystrophy (secondary dystroglycanopathies). Our results represent a major conceptual advancement regarding a functional carbohydrate and shed light on the mechanism of protein‐carbohydrate interactions.

Support or Funding Information

Dr. Campbell is an investigator of the Howard Hughes Medical Institute. This work was supported in part by a Paul D. Wellstone Muscular Dystrophy Cooperative Research Center grant.
TGF‐beta Regulation by the Matricellular Protein Thrombospondin 1
Authors: Murphy-Ullrich Joanne E. , Lu Ailing , Lei Weiqi , Suto Mark J.
Published: April 2020

Thrombospondin 1 (TSP1) is a matricellular protein that plays multiple roles in disease. Activation of the TGF‐beta latent complex is a major regulatory node for controlling TGF‐beta in homeostasis and disease. TSP1 can regulate the conversion of latent transforming growth factor‐beta (TGF‐beta) to its biologically active form in certain fibrotic diseases and cancers. We have developed peptide and small molecule antagonists that block TSP1 binding to the latent complex and inhibit TSP1‐dependent activation of latent TGF‐beta. These antagonists reduce TGF‐beta activity and extracellular matrix production and fibrosis in multiple rodent models, particularly in fibrotic complications of diabetes. TGF‐beta also plays a role in the osteolytic bone destruction characteristic of the plasma cell cancer, multiple myeloma. In both immune competent syngeneic mouse and human xenograft models, we showed that treatment with the TSP1‐TGF‐beta antagonist reduced disease burden, TGF‐beta activity, and prevented bone destruction via a decrease in osteoclasts and an increase in osteoblasts. Current studies are examining the role of the TSP1‐TGF‐beta pathway in immune dysregulation in multiple myeloma.

Support or Funding Information

The most recent studies (myeloma, drug development) are supported by grants from the Alabama Drug Discovery Alliance and the UAB Comprehensive Cancer Center pilot grant program, the American Society for Hematology Bridge Grant with supporting funds from the UAB Department of Pathology, and NIH grant 1R01CA175012.
Mitochondrial NAD Transport
Authors: Baur Joseph A. , Luongo Timothy , Mukherjee Sarmistha , Eller Jared , Chellappa Karthikeyani , Lu Mu-Jie , Cambronne Lulu
Published: April 2020

Tissue nicotinamide adenine dinucleotide (NAD) levels correlate with healthspan, falling with age or disease, and rising with exercise or caloric restriction. Moreover, the demonstration that supplemental NAD precursors drive beneficial effects in a variety of rodent models has led to a resurgence in interest in the basic biology of this molecule. Although it is widely recognized that NAD is present in the mitochondrial matrix and critical to the function of the organelle, the source of mitochondrial NAD has been debated. We recently used an isotopic labeling approach to demonstrate that direct uptake of intact NAD is one mechanism by which mitochondria are able to obtain this nucleotide. Here, we show that this activity is sufficient to restore respiratory capacity in NAD‐deficient isolated mitochondria, and identify SLC25A51 as a carrier that can mediate the transport of NAD across mitochondrial membranes. Compartment‐specific regulation of NAD concentration may be a crucial element in the adaptation of cells and tissues to changing metabolic environment that could be targeted therapeutically once the underlying mechanisms have been revealed.

Support or Funding Information

DK098656 to J.A.B., GM126897 to L.A.C.
Metabolic Competition in the Tumor Microenvironment
Authors: Haigis Marcia
Published: April 2020

Beyond energy production, mitochondria are dynamic organelles that generate metabolites important for redox control, anabolic macromolecules, and organelle and cellular communication. Not surprisingly, the dysregulation of mitochondria is associated with aging and numerous diseases, such as cancer, diabetes, and mitochondrial syndromes. Here, I will discuss nitrogen recycling in cancer cell proliferation. Specifically, I will discuss new ways to measure ammonia, and its fate beyond a cellular metabolic waste product.
Nascent Protein Selection and Triage at the Ribosome Exit Site
Authors: Shan Shu-ou , Wang Shuai , Yang Chien-I , Hsieh Hao-Hsuan
Published: April 2020

Proper protein biogenesis is a pre‐requisite for the generation and maintenance of a functional proteome. Accumulating data show that this process begins early, when nascent proteins begin to emerge from the ribosome. Indeed, the ribosome exit site is a crowded environment where a variety of ribosome‐associated protein biogenesis factors (RPBs) jostle for access to the nascent polypeptide. Within seconds, the nascent polypeptide must engage the correct set of factors and commit to the proper biogenesis pathway. These early decisions profoundly influence the folding, assembly, localization, maturation, and quality control of nascent proteins. This raises the question: How do these factors, which bind the ribosome at overlapping sites and prefers similar sequence features on the nascent polypeptide, compete or collaborate with one another to enable the efficient and accurate selection of nascent proteins into the proper biogenesis pathway? In this talk, I will describe recent works that begin to illustrate how the RPBs coordinate in space and time at the ribosome exit site and highlight the importance of this molecular crowding in enhancing the fidelity of individual protein biogenesis pathways.

Support or Funding Information

R01 GM078024, R01 GM107368
Nuclear mechanics in migrating cells
Authors: Lele Tanmay
Published: April 2020

Cells shape and position the nucleus by transmitting forces from the cytoskeleton onto the nuclear surface. In response to these forces, the nucleus can deform and/or it can move. Nuclear movement will occur when there is a net differential in mechanical force across the nucleus, while nuclear deformation will occur when mechanical forces overcome the mechanical resistance of the various structures that comprise the nucleus. In this talk, I will describe our efforts to 1) identify the sources of mechanical forces and quantify the magnitude of mechanical force generation on the nucleus, 2) understand the mechanical response of the nucleus to these forces, and 3) uncover the relevance of nuclear force transfer in cell and tissue function.

Support or Funding Information

NIHNSF
Clocks, Hourglasses, and History‐dependent Clocks
Authors: Murugan Arvind , Husain Kabir , Pittayakanchit Weerapat , Chew Justin , Leypunskiy Eugene , Lin Jenny , Pattanayak Gopal , Rust Michael
Published: April 2020

Many organisms have free‐running circadian clocks to anticipate the time of the day, including the Kai protein‐based clock in the cyanobacterium Synechococcus elongatus. However, other species have an ‘hourglass’ timer, such as the cyanobacterium Prochlorococcus marinus. What conditions favor an hourglass timer or a free running clock over the other? We argue that this evolutionary choice is influenced by the noise levels in the external environment (e.g., light fluctuations due to weather) relative to noise levels in the internal environment of the cell (e.g., molecular fluctuations). Besides different clock dynamics in different species, we find that the clock of a single species, S. elongatus, exploits a clock‐metabolic coupling to tune its clock dynamics towards an hourglass timer to deal with changing noise levels.

Support or Funding Information

K.H. thanks the James S. McDonnell Foundation for support via a Postdoctoral Fellowship. A.M. thanks the Simons Foundation for support.
Preventing and Overcoming Sexual Harassment
Authors: Helman Alex
Published: April 2020

The 2018 National Academy of Science report on Sexual Harassment of Women: Climate, Culture, and Consequences in the Academic Sciences, Engineering and Medicine revealed just how prevalent the sexual harassment of women is in STEM. The report demonstrated that 50% of women faculty and staff and 20–50% women students encounter or experience sexually harassing conduct in academia. It also detailed the effects of this harassment to the STEM community, concludes that system‐wide changes to the culture and climate in higher education are needed to prevent and address sexual harassment, and provides a roadmap for institutions of higher education to make these changes.

Since the release of the report, the National Academies have joined with over 40 colleges, universities, and research institutions to launch an Action Collaborative on Preventing Sexual Harassment in Higher Education. The purpose of the Action Collaborative is to bring together leaders from academic institutions and key stakeholders to work toward targeted, collective action on addressing and preventing sexual harassment across all disciplines and among all people in higher education. This session will focus on the report’s key findings and recommendations for implementing changes that can prevent sexual harassment and promote equity within scientific organizations and institutions and will provide an overview of the ongoing work of the Action Collaborative on Preventing Sexual Harassment in Higher Education.

Support or Funding Information

NSF, NIH, NASA, NOAA, NIST, Luce Foundation, Burroughs Wellcome Fund, Alfred P. Sloan Foundation
Promoting STEM identity: A Vision for Building Tomorrow’s STEM Leaders
Authors: Rodriguez Sarah
Published: April 2020

This talk is focused on considering the intersections of identity in our quest to build tomorrow’s STEM leaders and influence cultural and structural change in our labs, departments, campuses and fields. This session will share information related to understanding and honoring the multitude of identities that students are bringing with them into the classroom as well as challenge audience members to think about how these considerations can work towards creating more equitable STEM educational outcomes.
Lipids and Hedgehogs
Authors: Salic Adrian , Wierbowski Bradley , Petrov Kostadin
Published: April 2020

The Hedgehog cell‐cell signaling pathway governs critical processes in the embryonic development of most animals, in adult stem cell maintenance, and in cancer. The pathway is activated by the secreted Hedgehog morphogen, such as the prototypical vertebrate homologue, Sonic hedgehog (SHH). SHH is generated in the endoplasmic reticulum of signal‐producing cells, as a hydrophobic protein uniquely modified with palmitate at the N‐terminus and with cholesterol at the C‐terminus. These lipid modifications, which are critical for SHH function, render SHH strongly attached to the plasma membrane; yet the SHH morphogen must travel through the extracellular space, to reach responding cells located far away. I will present our recent work aimed at elucidating the biochemical mechanisms that allow the lipidated SHH morphogen to be released in diffusible form from producing cells, and then be delivered to its receptor, the tumor suppressor membrane protein Patched1, on the surface of responding cells.

Support or Funding Information

NIH/NIGMS R01 GM122920
Getting There: Thyroid Hormone Receptor Intracellular Trafficking
Authors: Allison Lizabeth A.
Published: April 2020

Trafficking of regulatory proteins into and out of the nucleus is fundamental to the function of all living cells. A long‐standing interest in my lab is exploring the diversity of signals regulating traffic control of the thyroid hormone receptors, TRα1 and TRβ1, transcription factors that either activate or repress the expression of target genes in response to thyroid hormone. Although primarily residing in the nucleus, TRα1 and TRβ1 shuttle rapidly between the nucleus and cytoplasm. Set against a backdrop of my path as a woman in STEM, milestones in our understanding of TR’s pathway to the nucleus will be reviewed, while at the same time the innovative contributions of the diverse community of talented scientists in my lab will be showcased. Along the way, we have identified multiple nuclear localization signals (NLSs) and nuclear export signals (NESs) within TRα1 and TRβ1 that interact with importins and exportins, respectively, to mediate translocation across the nuclear envelope. To begin to understand the molecular mechanisms underlying TR’s journey, we have focused on the role of post‐translational modifications and interactions with transcriptional coregulators in modulating intracellular localization. Using a combined approach in transfected human cells of fluorescence‐based nucleocytoplasmic scoring, fluorescence recovery after photobleaching (FRAP), overexpression, and knockdown studies, we have revealed that acetylation promotes cytoplasmic localization of TR, while Mediator subunit MED1 and nuclear receptor corepressor 1 (NCoR1) are key regulators of its nuclear retention. Given the pivotal role of TRα1 in human health, development, and metabolism, we hypothesized that in some types of cancer and endocrine disorders, TRα1’s highly regulated traffic control may be disrupted. To analyze key structural components of TRα1 and to further explore the correlation between TRα1 trafficking, misfolding, and disease, recently we have examined the impact of cancer‐associated and Resistance to Thyroid Hormone (RTH) syndrome mutations on TRα1 localization patterns. Results show striking shifts towards a more cytoplasmic localization for many of the mutants and an increased tendency to form cytoplasmic and nuclear aggregates. Although the journey is far from over, what has emerged so far is that the fine balance between nuclear import, nuclear retention, and nuclear export of TR is a critical control point for modulating the cellular response to thyroid hormone.

Support or Funding Information

NIH 2R15DK058028
Shedding Light on Phosphatidic Acid Signaling with Chemical Tools
Authors: Baskin Jeremy M.
Published: April 2020

The fidelity of intracellular signaling pathways requires that cells control the production of signaling agents in space and in time. Phosphatidic acid (PA) is both a central phospholipid biosynthetic intermediate and a multifunctional lipid second messenger produced at several discrete subcellular locations. The modes of action of PA can differ based on upstream stimulus, biosynthetic source, and site of production. How cells regulate the local production of PA to direct diverse signaling outcomes remains elusive. To begin to unravel these questions, we have focused our efforts on improving and expanding the toolkit for both visualizing and perturbing cellular PA production, with spatiotemporal precision. Toward the first goal, we have harnessed the exquisite selectivity of chemoenzymatic labeling and click chemistry tagging to develop a method for directly visualizing PA production by phospholipase D (PLD) enzymes. This method, termed IMPACT for Imaging PLD Activity with Clickable Alcohols via Transphosphatidylation, has revealed sites of PLD‐mediated PA signaling elicited by diverse physiological stimuli and features subcellular, organelle‐level resolution. To complement these tools for visualizing PA production, we have also generated a suite of light‐controllable, optogenetic PLDs to precisely generate tunable amounts of PA, on demand, at specific organelle membranes. Collectively, these new approaches represent powerful and precise approaches for revealing spatiotemporally defined functions of PA in response to physiological and pathological stimuli.

Support or Funding Information

NIH R00GM110121, NIH R01GM131101, NSF CAREER CHE‐1749919, Beckman Young Investigator, Sloan Research Fellowship
Cellular Communication via Adhesion
Authors: Arac Demet
Published: April 2020

Adhesion G Protein‐Coupled Receptors (GPCRs) are cell adhesion proteins that mediate cellular communication and play critical roles in embryonic and neural development. Their mechanisms of action remain poorly understood. In the past several years, three‐dimensional structures of adhesion GPCRs and their ligands have been reported at atomic resolutions and revealed distinct protein folds and unique structural features. In this talk, we will discuss these structures which, together with structure‐guided biochemical and functional analyses, provide hints for the mechanisms of trans‐cellular communication at the synapse and other cell‐cell contact sites.

Support or Funding Information

NIGMS, NIMH, Chicago Biomedical Consortium
Glutamine Transporter as a Target of mTOR Signaling Modulating Longevity
Authors: Sedivy John M.
Published: April 2020

Mice that express reduced levels of the c‐Myc gene (Myc+/− heterozygotes) are long‐lived. Myc hypomorphic mice display reduced rates of protein translation and decreased activity of the mammalian target of rapamycin (mTOR) complex 1 (mTORC1). Given the prominent effect of mTOR on aging, lower mTORC1 activity could contribute to the exceptional longevity and enhanced healthspan of Myc+/− animals. However, given the downstream position of MYC in these signaling cascades, the mechanism through which mTORC1 activity is downregulated in Myc+/− mice is not understood. We have found that the high‐affinity glutamine transporter SLC1A5, which is critical for activation of mTORC1 activity by amino acids, is a transcriptional target of MYC. Myc+/− cells display decreased Slc1a5 gene expression that leads to lower glutamine uptake and consequently reduced mTORC1 activity. Decreased mTORC1 activity in turn mediates an elevation of fatty acid oxidation (FAO) by indirectly upregulating the expression of carnitine palmitoyltransferase 1a (Cpt1a) that mediates the rate‐limiting step of β‐oxidation. Increased FAO has been noted in a number of long‐lived mouse models. Taken together, our results show that transcriptional feedback loops regulated by MYC modulate upstream signaling pathways such as mTOR and impact FAO on an organismal level.

Support or Funding Information

Supported by NIH grant R37 AG016694 to J.M.S.
Beneficial Effects of Inhibition of the Mitochondrial Pyruvate Carrier and the Mechanism of Action of Thiazolidinediones
Authors: Murphy Anne N.
Published: April 2020

We demonstrated a number of years ago that thiazolidinediones including pioglitazone (insulin sensitizers used in the treatment of type 2 diabetes) have a direct inhibitory effect on the mitochondrial pyruvate carrier (MPC). This metabolite transporter of the inner mitochondrial membrane is responsible for carrying pyruvate from the cytoplasm into mitochondrial matrix for further oxidation, and is key to determining the pattern of cellular substrate oxidation. Since then, multiple studies have described somewhat counter‐intuitive findings of potential benefit of loss of MPC activity through genetic or pharmacologic means in normal cells both in vitro and in vivo. For instance, we have provided evidence that loss of MPC activity in myocytes induces changes consistent with insulin sensitization, including enhanced fatty acid oxidation, elevation of glucose uptake, and phosphorylation of AMPK, similar to what is observed in the skeletal muscle of diabetic patients treated with pioglitazone. Perhaps the more surprising finding was in primary cultures of cortical neurons. Mapping the pattern of neuronal metabolism upon MPC inhibition using stable isotope tracing and metabolomics allowed us to determine the extent of metabolic flexibility in neurons, and determine whether adjustments in neuronal substrate oxidation could affect susceptibility to injury by excessive exposure to the neurotransmitter glutamate. We found that metabolism of cortical neurons in culture and hippocampal slices is characterized by metabolic plasticity, and oxidative metabolism can be maintained in spite of large reductions in mitochondrial pyruvate uptake because of a selective increase in glutamate oxidation as an energy substrate, even in the presence of ketone bodies. Increased glutamate oxidation decreased the glutamate available for packaging into synaptic vesicles and synaptic release and, in turn, minimized the positive feedback cascade of excitotoxic injury. Thus, reductions in mitochondrial pyruvate metabolism can be neuroprotective. These findings will be placed in the context of other studies designed to enhance healthy energy metabolism in neurological disease, as well as a re‐evaluation of the mechanism of action of thiazolidinediones.

Support or Funding Information

NIH R01NS087611
Reprogramming cell fates by RNA binding proteins in stem cells and cancer
Authors: Ito Takahiro
Published: April 2020

Stem cells and cancer share a characteristic potential of self‐renewal, which is essential for long‐term maintenance of both cell types in vivo. Similar to a hierarchy of stem and progenitor cells in normal tissues, many types of tumors are maintained by a small population of self‐renewing cancer cells while the bulk of the tumor is consisted of more differentiated cells with no or limited renewal activity. The self‐renewing cancer cells, or cancer stem cells, are often resistant to conventional therapies and thereby mediate tumor relapse. With the ability to self‐renew and propagate the tumor, cancer stem cells also contribute to metastasis and disease progression to a more aggressive, often fatal, disease phase. Therefore, regulatory mechanisms of stem cell fates have emerged as one of the promising areas for targeted cancer therapies. Recent studies have demonstrated that RNA binding proteins play major roles in both normal and malignant stem cells. We are particularly interested in how RNA binding proteins affect stem cell potentials and contribute to disease development in myeloid leukemia and would like to share our findings on their roles in the branched‐chain amino acid metabolism and stem cell maintenance.

Support or Funding Information

Supported by the Research Scholar Grant from the American Cancer Society.
RNA, Chromatin, and the Coordinated Control of Gene Expression
Authors: Johnson Tracy
Published: April 2020

RNA splicing is carried out by a large ribonucleoprotein machine, the spliceosome. Biochemical dissection of the splicing reaction has uncovered dynamic spliceosome rearrangements that are critical for proper recognition of splice sites and removal of introns. Recently, there has been growing evidence that assembly of the spliceosome onto pre‐mRNA occurs co‐transcriptionally, while the RNA polymerase is actively engaged with a chromatin template, which raises the question of how transcription, and more specifically, the state of the chromatin affects spliceosome assembly. Here we describe how conserved chromatin modifications influence spliceosome assembly to affect splicing outcomes and how changes in splicing allow cells to respond appropriately to their environment.

Support or Funding Information

NIH/NIGMS RO1 GM085474 HHMI 52008140