bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cyclophilin A is Crucial for Listeria and Salmonella Invasion and Cell‐to‐Cell Spreading
Authors: Dhanda Arandeep , Warren Kiera , Guttman Julian 
Published: November 2023

The actin cytoskeleton is a common target for a variety of pathogens. Listeria monocytogenes (Listeria) bacteria control the actin polymerization machinery within eukaryotic cells for their entry, intracellular motility and subsequent spreading from one cell to another. These microbes use actin‐rich structures called comet tails to generate protrusions at the plasma membrane (referred to as listeriopods) for cell‐to‐cell spreading. Unfortunately, the precise molecular mechanisms governing this process remain elusive. Another actin‐hijacking bacterial pathogen is Salmonella typhimurium (Salmonella). These bacteria exploit actin‐based membrane ruffling in order to enter cells. Although actin regulators have been linked to this process, a thorough understanding of the molecular constituents and their functions at these structures has not yet been investigated. We have previously shown that the peptidyl prolyl cis‐trans isomerase (PPIase), cyclophilin A (CypA), a cytosolic protein involved in protein folding, is recruited to actin‐rich structures generated by Listeria. Here we expanded on our previous discovery and tested the hypothesis that CypA is important for the pathogenesis of Listeria. Infections of murine fibroblasts depleted of CypA revealed that listeriopods were structurally collapsed, suggesting a unique role of cellular PPIases during cell‐to‐cell spreading of Listeria. Importantly, when CypA was reexpressed in these cells, listeriopods appeared normal. Curiously, cytoplasmic comet tails remained morphologically unchanged when CypA was absent. We also found that CypA is recruited to actin‐rich membrane ruffles generated by Salmonella during its entry into cells. Surprisingly, invasion assays of murine fibroblasts showed that invasion by Listeria and Salmonella increases significantly in cells knocked‐out for CypA. These results suggest a novel membrane‐associated mechanism whereby CypA regulates the efficiency of invasion and cell‐to‐cell transmission of bacteria.Support or Funding InformationGrant Funding Source: NSERC and departmental funds
Phantageusia: The Presence of Taste Distortions Inhibited by Repetitive Transcranial Magnetic Stimulation (rTMS)
Authors: Henkin Robert I , Abdelmeguid Mona , Knoppel Alexandra B , Potolicchio Samuel J 
Published: November 2023

Phantageusia is an unpleasant, usually persistent obnoxious taste in the oral cavity which occurs in the absence of any oral stimulus and which affects many patients in the United States. It has been considered a type of sensory hallucination. It usually occurs after a pathological event such as an influenza‐like illness, head injury or Parkinson disease which causes loss of taste acuity. Magnetic resonance spectroscopy (MRS) of brain in patients with this symptom revealed a lower than normal level of brain gamma‐aminobutyric acid (GABA). We have studied 30 patients with phantageusia and treated them with rTMS with 20 stimuli at intervals of 1–5 sec applied repeatedly first with sham stimulation to shoulder, neck and head at an intensity of 0.2 T and then with full stimulation to the head only at an intensity of 1.1 T. Quantitative changes in phantageusia presence was determined after both sham and active rTMS on a 0–100 scale with 100 indicating complete phantageusia inhibition and 0 indicating no change in distortion. Sham stimulation elicited no change in phantageusia or its intensity. rTMS inhibited phantageusia in 24 of the 30 patients with a mean intensity decrease of 49%, complete inhibition of phantageusia in four patients and 90% inhibition in two others. Repeat MRS in patients treated successfully demonstrated significant increases in brain GABA over the untreated state. Phantageusia inhibition commonly lasted months‐years without recurrence. In some patients repeat rTMS was necessary to inhibit phantageusia more effectively. rTMS is an effective method to inhibit phantageusia related to increases in brain GABA.Support or Funding InformationNone
Let There Be Force: Modeling Cell‐ECM Interactions During Cancer Invasion
Authors: Jiang Yi 
Published: November 2023

Extracellular matrix (ECM), the fibrous material that forms a network embedding cells in a tissue, significantly affects many aspects of cellular behavior, including cell movement and proliferation. Transgenic mouse tumor studies indicate that excess collagen, a major component of ECM, enhances tumor formation and invasiveness. Moreover, cell interactions with the collagen matrix result in aligned fibers that facilitate cell invasion. However, the underlying mechanisms are unclear, partially because the properties of ECM are complex, with diverse topographies and mechanical properties depending on various biophysical parameters. We have developed a three‐dimensional elastic computational fiber network model, and parameterized it with in vitro collagen experiments. The model can fill the gap between microscopic single collagen fiber studies and macroscopic collagen gel studies. We further developed a multiscale biomechanical cell migration model that interacts with the collagen network, and studied plasticity of cell migration in 3D ECM. This model is the first step toward a fully biomechanical cell‐matrix interaction model for changes in matrix organization during cell migration and tumor invasion.Support or Funding InformationThis work has been supported by the National Institute of Health 5U01CA143069.
A New Look at the Alveolar Macrophage
Authors: Bhattacharya Jahar 
Published: November 2023

Severe lung inflammation can lead to life‐threatening conditions such as acute lung injury (ALI) and the Acute Respiratory Distress Syndrome (ARDS). Alveolar macrophages are critical to these mechanisms. Not only do they clear debris, but as immune sentinels they direct the lung's pro‐ and anti‐inflammatory responses to optimize gas exchange. Despite the importance of macrophages in lung biology, a major difficulty is that the bulk of our understanding of lung macrophage function comes from studies on cells isolated from lung tissue or the bronchoalveolar lavage (BAL). Since cell isolation may change cell function, studies of macrophages in intact alveoli are required.Live‐lung imaging studies provide a means for direct studies of alveolar macrophages in situ. The studies reveal that resident alveolar macrophages adhere to the alveolar epithelium (AE) and resist washout. These cells are called sessile alveolar macrophages (SAMs) to distinguish them from macrophages that can be washed out and recovered in the bronchoalveolar lavage (BAL), as well as from lung macrophages that are derived from adult bone marrow‐derived monocytes. About half of the SAMs form stable gap‐junctional channels (GJCs) with the AE. Remarkably, SAMs signal through these GJCs to suppress the lung's exuberant inflammatory response to lethal endotoxin challenge.Pathogen detection mechanisms by SAMs remain unclear. One possibility is that pathogen detection involves the alveolar wall liquid (AWL). The alveolar distribution of SAMs is approximately 1 per 3 alveoli. Moreover, SAMs are non‐migratory. Hence it is possible that pathogen detection occurs when AWL flow convectively delivers the pathogens to SAMs. Chloride secretion by the alveolar cystic fibrosis transmembrane conductance regulator (CFTR) causes AWL flow. The flow is outward from alveoli towards the alveolar duct. In mice bred to specifically delete CFTR in alveolar type 1 (AT1) epithelial cells, AWL secretion stops and alveolar clearance of bacteria is decreased. These data support the hypothesis that pathogen delivery through AWL flow generated by AT1 cells induces proinflammatory responses in SAMs. Thus, alveolar CFTR may determine SAM‐induced pro‐ or anti‐inflammatory mechanisms in ALI.Support or Funding InformationSupported by NIH grant HL57556.
Carbon metabolism of parasitic protozoa: strategies for surviving in intracellular niches
Authors: McConville Malcolm , Saunders Eleanor , Sernee Fleur , Blume Martin , Kloehn Joachim , Ralton Julie 
Published: November 2023

Many parasitic protozoa, including Plasmodium spp, Toxoplasma gondii and Leishmania spp, proliferate within intracellular niches in their mammalian hosts. Despite many decades of research, we still have an incomplete understanding of the physiological state and metabolism of these intracellular stages and their capacity to adapt to different growth conditions during infection. This information is crucial for understanding the molecular basis of host‐parasite interactions, parasite responses to drugs, and for developing new anti‐parasitic therapies. While genome‐wide reconstructions have defined many aspects of parasite metabolism, more than half of the protein‐encoding genes have unknown function or have inferred functions from other highly divergent eukaryotic organisms. In order to experimentally validate the operation of predicted pathways, as well as to identify new/unanticipated metabolic pathways in these organisms, we have combined comprehensive metabolomic profiling approaches with 13C‐ and 2H‐stable isotope labeling approaches and imaging mass spectrometry. These studies have highlighted aspects of central carbon metabolism in intracellular parasite stages that have diverged from comparable pathways in the mammalian host. In particular we have identified a number of regulatory mechanisms that involve energy‐wasting futile cycles that appear to be critical for parasite growth and survival. These studies suggest that parasite central carbon metabolism may harbor a number of potential new drug targets.Support or Funding InformationThis work was supported by the Australian National Health and Medical Research Council
Dissecting the role of the Rad51 paralogs during double‐strand break repair
Authors: Bernstein Kara , McClendon Tiffany B , Sullivan Meghan R , Godin Stephen K , Gaines William , Sung Patrick , Yanowitz Judith 
Published: November 2023

Double‐strand breaks (DSBs) are one of the most cytotoxic forms of DNA damage. Defects in DSB repair are associated with cancer predisposition, as well as, several heritable diseases including Fanconi anemia. Our work has centered around Rad51 paralog function during DSB repair. Importantly, mutations in the human Rad51 paralogs are found in tumors and also lead to Fanconi anemia. Due to the embryonic lethality of the mouse knockout models and the low abundance and insolubility of the human proteins, there is very limited understanding as to how the Rad51 paralogs function to maintain genomic integrity. To circumvent these obstacles, we are studying the role of a unique Rad51 paralog‐containing complex, called the Shu complex, in the budding yeast S. cerevisiae and the nematode C. elegans. Although the Shu complex was discovered 10 years ago and is critical for DSB repair, its molecular function has remained elusive. We discovered that the yeast Shu complex is highly conserved from archaea through humans. Furthermore, we have identified direct physical interacting partners of the yeast and worm Shu complex and to show that these interactions are necessary and sufficient for the biological efficacy of the Shu complex during DSB repair. We define a molecular role for the yeast and worm Shu complexes in Rad51 presynaptic filament assembly, and thus for the first time gained insight into its mechanistic function. Our work has important implications for how the Rad51 paralogs and the human Shu complex function to prevent tumorigenesis and Fanconi anemia.Support or Funding InformationThis work was supported by the National Institutes of Health (GM088413 and ES024872) to K.A.B.
Observations on the Cellular Dynamics of a Metabolic Complex, the Purinosome
Authors: Benkovic Stephen , Chan Chung Yu (Keith) , Kim Doory , Pedley Anthony , Zhuang Xiaowei 
Published: November 2023

For several decades sequential metabolic enzymes had long been hypothesized to form multi‐enzyme complexes in cells to regulate metabolic flux. Single molecular fluorescence imaging in live cells of the six human enzymes involved in de novo purine biosynthesis uncovered the reversible formation of a metabolic multi‐enzyme complex, the “purinosome”. Purinosome formation was found to be sensitive to changes in purine demands and assisted by molecular chaperones. In cells lacking purine salvage enzymes, purinosome levels were enhanced. Despite the transient nature of this complex, the flux through the de novo pathway was increased in cells containing a high density of purinosomes, which is consistent with its function. Imaging experiments revealed the proximity of these complexes near mitochondria and along microtubules. The question then is to what extent are there relationships between these subcellular structures and the purinosome? I will discuss imaging analyses that explain the cellular dynamics of the purinosome near these structures in hopes to further understand how a cell responds to purine demand to fulfill its metabolic requirements.Support or Funding InformationNational Institutes of Health, #GM024129
Sphingosine‐1‐Phosphate: A Bridge From Bench To Clinic
Authors: Spiegel Sarah 
Published: November 2023

There is growing evidence that sphingosine‐1‐phosphate (S1P), a bioactive sphingolipid signaling molecule formed inside cells by sphingosine kinases (SphK1 and SphK2), regulates many physiological processes involved in obesity, inflammation and breast cancer. Patients with breast cancer have elevated levels of SphK1 that correlate with poor prognosis. Although most of the actions of S1P are mediated via specific receptors (S1PR1‐5), we have shown that nuclear S1P formed by SphK2 is an endogenous inhibitor of histone deacetylases (HDACs). Obesity, that is now endemic, increases breast cancer risk and is associated with worse prognosis, which may be due in part to chronic inflammation induced by obesity, the high frequency of triple negative breast cancer (TNBC), and ineffective hormonal therapy. This lecture will be highlight the role of the SphK/S1P/S1PR axis in obesity promoted breast cancer progression, and explain its involvement in a feed‐forward amplification loop leading to activation of the master transcription factors NF‐kB and STAT3. Focus will also be on a new mechanism of action in cancer of the pro‐drug FTY720/fingolimod that is approved for treatment of multiple sclerosis. The sphingosine analogue FYY720 is phosphorylated in the nucleus by SphK2 to the active form FTY720‐P that like S1P binds and inhibits class I HDACs. Finally, new therapeutic approaches that target the S1P axis for treatment of hormonal therapy resistant breast cancer will be discussed.Support or Funding InformationSupported by NIH grants RO1CA061774 and RO1GM043880 and the Department of Defense BCRP program award W81XWH‐14‐1‐0086.
Mitochondrial Protonophores For Treatment of NAFLD/NASH and Type 2 Diabetes
Authors: Shulman Gerald I 
Published: November 2023

This presentation will focus on the cellular mechanisms of insulin resistance in humans and the role of ectopic lipid deposits in liver and skeletal muscle in its pathogenesis. Specifically this talk will review recent studies that have implicated diacylglycerol activation of novel PKCs as the molecular trigger for lipid‐induced insulin resistance in these tissues. This talk will also review recent studies that identify the link between adipose tissue inflammation and increased rates of hepatic gluconeogenesis in type 2 diabetes as well as novel mitochondrial protonophore therapies that reverse type 2 diabetes and non alcoholic steatohepatitis through promotion of subtle increases in hepatic mitochondrial inefficiency and reductions in ectopic lipid deposition in liver and skeletal muscle.Support or Funding InformationThis work was supported by grants from NIDDK/NIH: R01 DK‐40936, R01 DK‐49230, the American Diabetes Association and HHMI.
Development of Nonalcoholic Fatty Liver in Superoxide Dismutase‐1 Knockout Mice Was Associated with Altered Expression of Hepatic Fibroblast Growth Factor‐21
Authors: Chakraborty Debrup , Lei Xin Gen 
Published: November 2023

Superoxide dismutase‐1 (SOD1) is a well‐known intracellular antioxidant enzyme, and our laboratory has been studying impact and mechanism of the SOD1 knockout on glucose and lipid metabolism in mice. Non‐alcoholic fatty liver disease begins with an excessive accumulation of triglyceride in the liver, a condition that can eventually leads to hepatocyte injury, fibrosis, steatohepatitis, and cirrhosis. In the present study, we found hepatic triglyceride in the SOD1 knockout mice two‐fold higher (P < 0.05, n = 6) than that of their wild‐type controls starting at 3‐wk of age. Hepatic expression of more than 70 key genes related to responses or regulations of oxidative and endoplasmic reticular stresses, glucocorticoid receptor, casein kinase, Wnt, transforming growth factor‐β, caspase 1, and lipid metabolism was compared between the knockout and wildtype mice. Approximately one‐third of these genes were altered (P < 0.05) by the SOD1 knockout over the wild‐type control. Strikingly, the change of fibroblast growth factor‐21 (FGF21) ranked the highest among all the affected genes by the knockout. To determine if there was a cause‐effect relationship between the SOD1 knockout and the change in hepatic FGF21 mRNA levels, we treated primary hepatocytes isolated from the wild‐type mice with the SOD inhibitor (diethyl‐dithio‐carbamic acid at 0 and 50 μM for 6, 12 and 24 h), and found a four‐fold increase (P < 0.05) in FGF21 mRNA level due to the treatment. Subsequently, we injected (intraperitoneal) the SOD1 knockout mice (n = 12, male, 3‐wk old) with the SOD mimic [copper (II) 3, 5‐diisopropylsalicylate hydrate, 30 mg/kg body weight] every other day for 1 wk. The mimic injection resulted in a down‐regulation (P < 0.05) of hepatic FGF21 mRNA compared with the vehicle (80% Phosphate‐buffered saline, 10% Dimethyl sulfoxide and 10% Tween‐80) injection. In conclusion, knockout of SOD1 led to a substantial overexpression of the hepatic FGF21 mRNA, which may serve as one of the mechanisms for the development of non‐alcoholic fatty liver disease in the knockout mice.Support or Funding InformationSupported in part by a NIH grant DK53018.
Effects of HMB and beta‐alanine co‐supplementation and running wheel activity on skeletal muscle morphometry and metabolomics in aged rats
Authors: Garvey Sean M. , Desai Janish 
Published: November 2023

Dietary intervention with either beta‐hydroxy‐beta‐methylbutyrate (HMB) or beta‐alanine (BA) has been shown to improve muscle strength and physical working capacity, respectively, in elderly subjects. We examined the effects of 8 weeks HMB (343 mg/kg bw) and BA (274 mg/kg bw) co‐supplementation (HMB+BA) on skeletal muscle morphometry and metabolomic profiles in aged, male Sprague Dawley rats (22 months), versus AIN‐93M control diet (CTL). Rats were also assigned either continuous voluntary running wheel access (RW+) or cage‐matched without running wheel access (RW‐). Thus, we examined a total of 4 experimental groups (9–10 rats per group). RW activity across the 8 weeks of study was very low across both diet groups, and the HMB+BA diet had no significant effect on RW activity compared to rats fed CTL diet (84 ± 17 m/day vs. 73 ± 16 m/day). The HMB+BA diet also had no significant effects on food intake or body weight in either RW‐ or RW+ rats. Across both RW+ groups, average % body weight change decreased compared to the RW‐ groups (0.2% vs. 6.1%, P<0.00001). RW activity also decreased average weekly food intake by 6.1% (125 ± 2 g vs. 133 ± 2 g, P=0.023). Neither HMB+BA supplementation nor RW activity had significant effects on forelimb grip strength or absolute hindlimb muscle weights (i.e., gastrocnemius, soleus, plantaris). HMB+BA/RW‐ rats showed a trend for increased gastrocnemius myofiber cross‐sectional area (3430 ± 134 μm2 vs. 3802 ± 152 μm2, P=0.084), however with minimal effect on myofiber Feret diameter, relative to CTL/RW‐ rats. Metabolomic profiling highlighted effects of RW activity and HMB+BA diet on carbohydrate and lipid metabolism. In gastrocnemius, RW activity was associated with a decrease in the glycolytic intermediate, fructose‐6‐phosphate, and this effect was more pronounced in combination with the HMB+BA diet. The HMB+BA/RW+ group also showed a significant reduction in pyruvate and citrate, relative to all other groups. Adenine and 2′‐ deoxycytidine levels were also less abundant with the HMB+BA diet. Metabolomic profiling was also carried out on rectus femoris muscle from the RW‐ groups only, and the HMB+BA diet was associated with increased long chain fatty acids (LCFAs), relative to CTL diet. Increased LCFAs may indicate enhanced beta‐oxidation of lipids, and the aforementioned decreases in glycolytic intermediates suggest improved carbohydrate metabolism, as we have previously shown that these biochemicals are more abundant with age in muscle. Altogether, these data suggest that both low‐volume physical activity and HMB+BA co‐supplementation contribute to improved bioenergetics in aging skeletal muscle.Support or Funding InformationFunding for this study was provided by Abbott Nutrition.
An integrated nutrition‐sensitive health and agriculture intervention to increase egg consumption among infants and young children in Upper Manya Krobo, Ghana
Authors: Atuobi‐Yeboah Afua , Marquis Grace S , Colecraft Esi , Kanlisi Roland , Aryeetey Richmond , Klevor Moses 
Published: November 2023

Poor dietary quality and nutritional status among young children is common in rural low‐income households in Upper Manya Krobo District (UMKD), Ghana. Consumption of animal source foods can improve diet and growth outcomes. The Nutrition Links Project is a 5‐y capacity‐building project to improve nutrition and well‐being of vulnerable populations in UMKD. The project includes a small cluster randomized controlled trial that provides home gardening, health, nutrition education, and poultry entrepreneurial activities for caregivers who had a 0‐to 12‐mo‐old infant and were living in the intervention communities at enrollment (IN; n=102). Caregivers in the control (CT) communities (n=228) receive only the standard‐of‐care for nutrition, health, and agricultural extension provided by government staff. This on‐going study seeks to improve the diets and growth outcomes of young children, partly through increased egg consumption. For this analysis, longitudinal data comparing children's egg consumption during the previous day, were collected from caregivers at baseline and at the first follow‐up [IN (n=102); CT (n=228)], approximately 7 months after the intervention was implemented. At baseline, when infants were 8.7±4.1 mo old, few consumed eggs [IN (15.5%) and CT (20.8%)]. By the first follow‐up, there was a statistically significant difference in the percent of children consuming eggs (IN (28.4%) vs. CT (52.6%); P<0.001). The lower intake of eggs among IN children occurred despite the fact that IN caregivers had an increased access to eggs from the poultry enterprise. The negative effect during the early months of the intervention may reflect caregivers placing greater emphasis on egg sales for income and success of their poultry enterprise rather than home consumption. In‐depth evaluation is needed to better understand caregivers’ behaviours and to determine the project effect on the total diet. Nutrition education activities continue to encourage use of eggs as well as diverse nutrient‐rich foods in UMKD children's diets to ensure the nutrition‐sensitive agriculture intervention achieves the expected objective of improving diets and nutritional status of project participants.Support or Funding InformationFunded by the Department of Foreign Affairs, Trade, and Development (DFATD) of the Government of Canada