bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanotransduction through Integrin‐mediated Adhesions
Authors: Schwartz Martin
Published: April 2020

Integrin‐mediated adhesions both transmit mechanical tension and sense the mechanical properties of the extracellular matrix such as stiffness and applied strains. Major human pathologies including hypertension, atherosclerosis, heart failure and fibrosis involve altered forces and tissue stiffness, or altered cell sensing of these variables. My lab investigates the basic mechanisms by which cells sense matrix stiffness, applied strains and fluid shear stress, and how these sensing mechanisms contribute to cardiovascular disorders. I will present our latest work on elucidation of these mechanotransduction pathways and their role in cardiovascular remodeling and disease.

Support or Funding Information

NIH
Mechanical Force and Notch Signaling
Authors: Gordon Wendy
Published: April 2020

The mechanical microenvironment of a cell guides cellular processes such as migration, differentiation, division, and signaling, and is thus often altered in disease. At a molecular level, mechanical stimuli alter conformations of mechanosensing proteins to communicate the stimulus to the cell interior and effect a downstream cellular response in a process called mechanotransduction. Measuring tensions sensed by cellular proteins and how tensions are altered by cellular context will lead to better understanding of the molecular mechanisms used in mechanosensing in disease‐related processes such as tumor migration. Tools to measure molecular level tensions have only emerged more recently to characterize the pN forces present across mechanosensitive proteins and have been used to measure tensions sensed by focal adhesions proteins such as vinculin, talin, and integrins, as well as cadherins. Generally, genetically encodable molecular tension sensors contain a deformable peptide linker with well‐characterized extension in response to applied force flanked by two fluorescent proteins (FP). The extent of linker stretching due to mechanical force can measured by Förster resonance energy transfer (FRET) and subsequently be correlated to a quantifiable force. We developed a genetically‐encodable molecular tension sensor based on bioluminescence resonance energy transfer (BRET) that overcomes several limitations of FRET. Using BRET as a distance reporter in molecular tension sensors allows for more sensitive readouts due to the lack of autofluorescence and phototoxicity. BRET also offers the potential for use in vivo where light excitation is not able to penetrate into tissue. We demonstrate the utility of this tension sensor in vitro and in cell based assays, using vinculin as the model system to show an enhanced dynamic range compared to field standard FRET‐based sensors. We will then present measurements of tensions sensed between cells by Notch receptors.

Support or Funding Information

Pew Biomedical Scholar, R35 GM119483
Mechanisms Linking Mechanotransduction and Cell Metabolism
Authors: DeMali Kris , Salvi Alicia , Bays Jennifer
Published: April 2020

External forces are sensed by cell surface adhesion receptors, such as E‐cadherin, and trigger robust actin cytoskeletal rearrangements that allow the cell to withstand the force. These actin rearrangements are energetically costly and require approximately half of the ATP in a cell. Previous work in our laboratory demonstrated that in response to force, E‐cadherin signals for enhanced energy production by stimulating AMP‐activated protein kinase (AMPK). AMPK triggers glucose uptake and its oxidation to ATP thereby providing the energy necessary for actin cytoskeletal remodeling. How mechanical force stimulates glucose uptake remains completely unexplored. In this study, we identify glucose transporter‐1 (GLUT1) as a force‐sensitive protein that is highly enriched in the plasma membrane in cells under tension. GLUT1 is necessary for the uptake of glucose and the reinforcement of the actin cytoskeleton that occurs when E‐cadherin experiences force. Intriguingly, GLUT1 is recruited to the cell‐cell junctions and forms a complex with E‐cadherin via a novel linkage mediated by the spectrin adaptor protein, Ankyrin G. Loss of Ankyrin G binding to E‐cadherin inhibits GLUT1 retention to the membrane, glucose uptake, and reinforcement of the actin cytoskeleton in response to force. This study provides the first mechanism for how cell mechanics stimulates the uptake of glucose.

Support or Funding Information

This work is supported by NIH Grant #GM112805.
Toward the solution of the protein‐structure prediction problem
Authors: Zhang Yang
Published: April 2020

Protein structure prediction aims to determine the spatial location of every atom in protein molecules from the amino acid sequence by computational modeling. Depending on whether homologous structures are found in the Protein Data Bank (PDB), protein structure prediction have been historically categorized into template‐based modeling (TBM) and template‐free modeling (FM, or ab initio folding). In this talk, we first review recent progress in computer‐based protein structure prediction and show that the problem can be solved in principle (but not yet realistically) by TBM in case that fold‐recognition algorithms could identify the best structural templates from the PDB. Next, we discuss protein structure prediction results in the most recent community‐wide blind CASP experiments, showing that new approaches combining ab initio folding and deep neural‐network contact and distance predictions, which are built on residue coevolution data from multiple sequence alignments, can result in consistent and successful folding of proteins with sequence longer than 200–300 amino acids with a root‐mean‐square deviation below 3–4 Angstroms. This progress essentially breaks through the 50‐years‐old modeling border between TBM and FM and makes the success of high‐resolution structure prediction no longer relying on the PDB library. It also demonstrates the promise to solve the problem of protein structure prediction in a foreseeable future, by integrating deep machine learning techniques and the rapid advancement of genome sequencing databases, with the aid of advanced structure assembly simulation algorithms.

Support or Funding Information

This work is supported in part by the National Institute of General Medical Sciences (GM083107, GM116960), the National Institute of Allergy and Infectious Diseases (AI134678), and the National Science Foundation (DBI1564756, IIS1901191).
PAMPs, DAMPs and SAMPs: Host Glycans are Self‐Associated Molecular Patterns, but subject to Microbial Molecular Mimicry
Authors: Varki Ajit
Published: April 2020

It has long been known that Pathogen‐Associated Molecular Patterns (PAMPs, e.g., lipooligosaccharides, LOS) and Danger‐Associated Molecular Patterns (DAMPs, e.g., fragments of endogenous hyaluronan) can be glycans or modified glycans. We have more recently emphasized that host glycans can also serve as Self‐Associated Molecular Patterns (SAMPs), e.g., sialic acid‐bearing glycans that are recognized by CD33‐related Siglecs on innate immune cells to dampen responses, or by complement Factor H to dampen complement‐mediated activation. However, several commensal or pathogenic organisms have evolved successful molecular mimicry of sialylated SAMPs, so as to hijack these mechanisms and suppress innate immune responses against them. Paired activating CD33rSiglecs have emerged in some lineages, presumably to counter hijacking by microbial molecular mimicry of sialylated SAMPs. Meanwhile, sialylated host SAMPs also have to evolve rapidly to escape from other pathogens that utilize them as targets to initiate infection. The ongoing pressures of these often‐competing selection forces can explain our finding that the sialic‐acid binding domains of CD33rSiglecs and Factor H show much higher than expected Ka/Ks ratios (an excess of non‐synonymous substitutions changing encoded amino acids, over synonymous substitutions). Examples can also be found of lineage‐specific complete loss of sialic binding e.g., via mutation of an essential arginine residue in some CD33rSiglec binding pocket—or even whole‐sale elimination of the binding domain e.g., alternate splicing out of the amino‐terminal V‐set domain of CD33/Siglec‐3. Such evolutionary changes can be either fixed or polymorphic within a given species. Further complexity arises because CD33rSiglec and Factor H can be directly engaged via protein:protein interactions, both with endogenous proteins such as Hsp70 and Vimentin, and with surface proteins of commensals e.g., the PorB protein of N. gonorrhea. The overall outcome is inter‐species or intra‐species variations in the intensity of innate immune responses, which can be reflected in relative susceptibility or resistance to infectious agents and/or harmful aggravation of endogenous inflammatory diseases. Perhaps because of the major changes in the sialome resulting from inactivation of the CMAH gene in the Homo lineage leading to humans, these and many other types of evolutionary changes appear to be very prominent in our species and in our pathogen regimes. This presentation will provide an overview of these topics and examples of our recent work in these areas.
Lipid Droplet Proteome Dynamics and Lipotoxicity
Authors: Olzmann James
Published: April 2020

Lipid droplets are ER‐derived neutral lipid storage organelles that function as cellular hubs of lipid metabolism, providing an “on demand” source of fatty acids for energy and sequestering fatty acids to protect cells from lipotoxic damage. Lipid droplet functions are controlled by associated integral and peripheral proteins. To understand the composition of lipid droplet proteomes, we recently developed a proximity labeling strategy to define high confidence lipid droplet proteomes. This approach uses lipid droplet‐targeted ascorbate peroxidase (APEX2), which enables the biotinylation of neighboring proteins in a spatially and temporally defined manner. Employing this method, we defined high confidence lipid droplet proteomes in multiple cell lines and identified pathways that impact lipid droplet proteome composition, uncovering a role for a ubiquitin‐dependent ER‐associated degradation (ERAD) pathway in the clearance of select lipid droplet proteins. A key function of lipid droplets is to sequester fatty acids to prevent lipotoxicity. To further understand how the cell responds to lipotoxic insults, we leveraged whole‐genome CRISPR‐Cas9 screens to dissect pathways that regulate lipid damage. For example, exploiting a synthetic lethal screening strategy, we discovered a new pathway that promotes cancer cell resistance to a regulated form of cell death known as ferroptosis, which involves the iron‐dependent accumulation of oxidatively damaged lipids. This study uncovered an unexpected role for non‐mitochondrial CoQ as a lipophilic antioxidant that prevents membrane damage. Together, our findings highlight the integration of systems level discovery approaches and cell biology methods as a powerful strategy to understand the mechanisms that regulate lipid droplets and lipotoxicity.

Support or Funding Information

This research was supported by grants from the National Institutes of Health (R00DK095921and R01GM112948) and from the American Heart Association (16GRNT30870005).
Cold‐Induced Lipokines in Energy Metabolism
Authors: Tseng Yu-Hua
Published: April 2020

Obesity and metabolic syndrome are rapidly increasing worldwide, leading to high morbidity and mortality in type 2 diabetes, cardiovascular disease, renal failure, and even some cancers. Centered to these pathologies is the adipose tissue. In addition to the energy‐storing white adipose tissue, brown and brown‐like beige adipose tissue (BAT) are specialized for thermogenic energy expenditure. Due to the high capacity of BAT in consuming glucose and fatty acids to generate heat and dissipate energy and the presence of BAT in adult humans, increasing the amount or activity of BAT has been considered an appealing approach for the treatment or prevention of obesity and its related metabolic disorders. Besides energy dissipation, at least part of the beneficial effects of BAT is due to its secretory function and consequent capacity to affect metabolic functions in other tissues such as muscle, WAT, and liver. Thermogenic adipocytes can synthesize and release factors such as peptides, lipids, or other metabolites, which may act as endocrine, paracrine, or autocrine agents to regulate physiological functions required for adaptive thermogenesis. Cold exposure is one of the most efficient ways to activate BAT and increases energy consumption. Short‐term cold exposure leads to significant improvement in insulin sensitivity. By utilizing mass spectrometry‐based lipidomics, we have identified novel lipid mediators (i.e., lipokines) derived from BAT, whose concentrations are increased in the circulation of cold exposed mice and humans. These lipokines act as a marker and stimulator of thermogenic activity and negatively correlates with body mass index and insulin sensitivity. Mechanistic studies demonstrate that cold‐induced lipokines can regulate glucose and fatty acid metabolism. These findings provide novel therapeutic approaches for the treatment of metabolic diseases by mimicking cold exposure.

Support or Funding Information

NIH (R01DK077097, R01DK102898, P30DK036836), US Army (W81XWH‐17‐1‐0428)
Local and systemic actions of hepatic fatty acid oxidation
Authors: Wolfgang Michael J.
Published: April 2020

Mitochondrial long chain fatty acid beta‐oxidation is required for hepatic ketogenesis and gluconeogensis during fasting, starvation and times of low carbohydrate intake. The liver has a large capacity and dynamic range for fatty acid oxidation to facilitate ketogenesis and gluconeogenesis. To gain a better understanding of the roles of hepatic fatty acid oxidation on liver function, we generated mice with a hepatocyte‐specific knockout of Carnitine Palmitoyltransferase 2 (Cpt2L−/−), an obligate step in mitochondrial long‐chain fatty acid β‐oxidation. Mice with a loss in hepatic fatty acid oxidation were able to maintain systemic glucose homeostasis during a 24hr fast, but did not produce ketone bodies. Systemic energy homeostasis was largely maintained by adaptations in hepatic and systemic oxidative gene expression mediated in part by a robust hepatic transcriptional response. Open chromatin assessed by ATAC‐seq and histone H3K9 ChIP‐seq analysis revealed that many genes induced in fasted Cpt2L−/− mice exhibited Pparα regulatory sites. To understand the contribution of Pparα, we generated Pparα;Cpt2L−/− double knockout mice. The deletion of Pparα in Cpt2L−/− mice largely blunted this transcriptional response, demonstrating the requirement for Pparα. Triglyceride hydrolysis has been shown to be critical for Pparα‐mediated transcriptional control. To determine the requirement of hepatic triglyceride hydrolysis on the Cpt2L−/− transcriptional response, mice were generated with a liver‐specific defect in triglyceride hydrolysis (AtglL−/−) and fatty acid oxidation (AtglL−/−;Cpt2L−/− double knockout). The loss of Cpt2 or Atgl resulted in largely independent effects on hepatocyte morphology, intermediary metabolism and gene expression in response to fasting. However, high fat feeding revealed the interaction of Atgl and Cpt2 as the loss of only one of these genes results in steatosis but the loss of both components resulted in significant inflammation and fibrosis. These data suggest that defects in mitochondrial fatty acid oxidation induce an exaggerated fasting response that initiates lipid dependent transcription to mediate changes in local and systemic physiology.

Support or Funding Information

This work was supported in part by a National Institutes of Health grant R01DK116746 to M.J.W.
N‐butylidenephthalide Attenuates Ventricular Arrhythmias by Preservation of Connexin43 in Rats with Myocardial Infarction
Authors: Lee Tsung-Ming , Lin Shinn-Zong
Published: April 2020

We have recently demonstrated that n‐butylidenephthalide, a major phthalide ingredient of Angelica sinensis, inhibits glycogen synthase kinase (GSK)‐3β and consequently attenuates free radical production. Connexin43 playing a role in ventricular arrhythmia after myocardial infarction is sensitive to redox status. This study was to determine whether n‐butylidenephthalide attenuated arrhythmias through modulating GSK‐3β/free radicals‐induced connexin43 by activating phosphoinositide‐3 kinase (PI3K)/Akt after myocardial infarction. After coronary ligation, male Wistar rats were randomized to either vehicle or n‐butylidenephthalide for 4 weeks. To assess the role of peroxynitrite in connexin43 phosphorylation, we also assessed 3‐morpholinosydnonimine (a peroxynitrite generator). Myocardial superoxide and nitrotyrosine levels were significantly increased and connexin43 levels were substantially decreased after induced myocardial infarction. These changes of superoxide, nitrotyrosine and connexin43 levels were blunted after n‐butylidenephthalide administration, as assessed by biochemistry, immunofluorescent analysis, Western blotting, and real‐time quantitative RT‐PCR. During programmed electrical stimulation, arrhythmic scores were significantly lower in the n‐butylidenephthalide‐treated infarcted rats than those in the vehicle‐treated infarcted rats. n‐butylidenephthalide significantly increased Akt and GSK‐3β phosphorylation in the border zone compared to vehicle after infarction. Inhibition of PI3K/Akt signaling by LY294002 and wortmannin prevented GSK‐3β phosphorylation to a similar extent, and blocked the effects of n‐butylidenephthalide on increased connexin43 phosphorylation. n‐butylidenephthalide‐treated hearts had significantly increased connexin43 phosphorylation, which was significantly decreased after adding 3‐morpholinosydnonimine. The long‐term administration of n‐butylidenephthalide was associated with decreased free radicals content and increased connexin43 levels through the PI3K/Akt‐dependent GSK‐3β pathway, which attenuated ventricular arrhythmias after infarction.
Comparison of serum cytokine measurement techniques between ELISA vs Multiplex
Authors: Ungaro Corey T. , Wolfe Anthony S. , Brown Shyretha D.
Published: April 2020

Enzyme‐linked immunosorbent assay (ELISA) has been classically described as the gold standard for serum cytokine analysis. However, multiplex array technologies are increasing in popularity, likely because of their ability to analyze large numbers of analytes with low sample volume compared to ELISA. However, few studies have directly compared serum cytokine results from ELISA and multiplex analytical techniques. Therefore, the purpose of this study was to determine differences in serum cytokine concentrations between ELISA and Multiplex techniques. Blood samples were collected from the antecubital vein of professional American football players during a competitive season. After clotting, blood was centrifuged and three 300 μL aliquots of serum were frozen at −80°C. IL‐1β, IL‐6, and TNF‐α were measured using ELISA (EMD Millipore, Sigma Aldrich) and Multiplex (EMD Millipore, MagPix) kits. For standardization, one technician carried out the respective protocol under the same laboratory conditions on the same samples. Descriptive statistics are shown as mean ± SD. Coefficients of variation (CV%), paired samples t‐test with 95% CI, and Pearson’s product‐moment correlations were used to compare cytokine analysis techniques. Results indicated that serum cytokine concentrations were not comparable between ELISA and Multiplex analytical techniques. IL‐1β (n=15) displayed significant variability between techniques with a CV% of 119.9 with ELISA reading 36.8 ± 32.4 pg/mL, intra‐assay CV%= 7.6 and Multiplex showing 1.1 ± 1.2 pg/mL, intra‐assay CV%= 6.8. IL‐6 (n=33) demonstrated substantial variability between techniques with a CV% of 126.9 with ELISA reading 340.2 ± 460.5 pg/mL, intra‐assay CV%= 15.3 and Multiplex showing 11.8 ± 20.2 pg/mL, intra‐assay CV%= 4.8. For TNF‐α (n=36) all ELISA samples were below the detection limit of 0.31 with the Multiplex detecting 8.8 ± 3.2 pg/mL, intra‐assay CV%= 7.9. Moreover, paired samples t‐tests showed considerable mean differences between analysis techniques for IL‐1β (−35.8 pg/mL, (95% CI, −51.6 to −19.9) t(17) = −4.8, p < 0.001) and IL‐6 (−328.4 pg/mL (95% CI,−490.0 to −166.7), t(32)= −4.1, p < 0.001. Pearson’s correlation between ELISA and Multiplex was not significant for IL‐1β [r(13) = 0.44, p = 0.068] or IL‐6 [r(31) = 0.25, p = 0.157]. The results suggest that differences in blocking agents between both techniques may be the source of erraticism. According to the results from this study comparisons between analytical techniques should be avoided.

Support or Funding Information

This study was funded by and the authors are employed by the Gatorade Sports Science Institute, a division of PepsiCo, Inc. The views expressed in this abstract are those of the authors and do not necessarily reflect the position or policy of PepsiCo, Inc.
The Zn2+‐Transporter ZnT6 Plays Important Role on Regulation of Cytosolic Free Zn2+ Through Modulation of Mitochondrial Zn2+ in Hyperglycemic Cardiomyocytes
Authors: Tuncay Erkan , Turan Belma
Published: April 2020

Free zinc ion (Zn2+), have physiological importance for mammals and is found to be less than 1‐nM in cytosol. However, intracellular free Zn2+ levels ([Zn2+]i) can increase dramatically under pathological conditions including hyperglycemia and cancer. Any increase in [Zn2+]i can also cause significant changes in several intracellular signaling pathways. However, that [Zn2+]i is well regulated by various ways in physiological conditions and that value can fluctuate dynamically in cardiomyocytes. It is accepted that there are two‐types of Zn2+‐transporters, one group of them is responsible Zn2+‐influx from extracellular space and/or organelles to cytosol (ZIPs) and the other group is responsible Zn2+‐efflux from cytosol (ZnTs). Since it is not known whether the Zn2+‐transporter ZnT6 has a role in the regulation of [Zn2+]i in cardiomyocytes under hyperglycemia, we used control and ZnT6 overexpressed H9c2 cells (rat embryonic ventricular cell lines) to investigate its role. In addition, H9c2 cells are incubated with normal (5.5‐mM; control) and high glucose (25‐mM; hyperglycemic) for 24‐h. Following the treatment, control and ZnT6‐overexpressed cells are transfected with Zn+2‐sensitive as well as cytosole, sarco/endoplasmic reticulum S(ER) or mitochondria targeted Förster resonance energy transfer (FRET) sensors to measure cytosolic, S(ER) and mitochondrial [Zn2+], respectively. Furthermore, we examined the mRNA, protein expression levels and intracellular localizations by using molecular, biochemical and immunofluorescence methods. Our results demonstrated that ZnT6 but not ZnT5 mRNA and protein level is increased under hyperglycemia, while ZnT6 overexpression caused increase of ZnT5 protein level. Our immunofluorescence/precipitation experiments showed that ZnT6 localized on mitochondria together with ZnT5 in H9c2 cells. Furthermore, our [Zn2+] measurements by fluorescence imaging showed that cytosolic and mitochondrial [Zn2+] are increased and S(E)R [Zn2+] is decreased in hyperglycemic H9c2 cells. We also found that, ZnT6‐overexpression caused mitochondrial [Zn2+] increase and decrease in cytosolic [Zn2+], without changing the S(E)R [Zn2+]. To understand the role of excess [Zn2+] on mitochondrial function, we used ZnT6 overexpressed or high Zn2+ incubated H9c2 cell lines to measure mitochondrial‐membrane‐potential (MMP), ROS and ATP production. We found that excess intracellular or mitochondrial [Zn2+] caused depolarization of MMP, increase in ROS and decrease in ATP production. Overall, our results showed that ZnT6 has a significant role on [Zn2+]i by modulating mitochondrial [Zn2+] and function in hyperglycemia.

Support or Funding Information

TUBITAK‐SBAG‐117S386TUBITAK‐SBAG‐119S661
Ameliorative Effect of Gum Acacia on Water Pipe Smoke ‐ Induced Testicular Impairment in Mice
Authors: Ali Badreldin H. , Al-Salam Suhail , Al-Balushi Khalid M. , Al-Za’abi Mohammed H. , Nemmar Abdeerrahim
Published: April 2020

We investigated some effects of water pipe smoke (WPS) exposure (30 min/day, for 30 days) in male mice, and the possible ameliorative of gum acacia (GA) coadministration thereon. Controls were exposed to air‐only (AE). Twenty‐four hours post last exposure, the levels of some plasma reproductive hormones, biochemical markers of inflammation, oxidative and nitrosative stress and testicular histopathology were assessed. The concentration of cotinine, the predominant metabolite of nicotine, was also measured in urine. WPS exposure induced a significant decreases in testosterone, estradiol, luteinizing hormone, and androgen binding protein. Inhibin B concentration was significantly increased. Plasma alkaline phosphatase, lipopolysaccharide binding protein, uric acid, and lactate dehydrogenase were all significantly increased following WPS exposure. In testicular homogenate, NF‐κB p65, Nrf2, interleukin‐1β, interleukin‐6, tumor necrosis factor –α, and transforming growth factor‐β1 were all significantly elevated after WPS exposure. WPS exposure decreased nitrite and total nitrite, glutathione reductase activity, and increased lipid peroxidation, cytochrome C, and 8‐Oxo‐2′‐deoxyguanosine. Histopathologically, there was slight reduction in the diameter of the seminiferous tubules with disorganized spermatogenesis. Cotinine concentration was significantly increased in the WPS‐exposed group compared with the control group. GA co‐administration mitigated the adverse actions of WPS measured. We conclude that daily exposure to WPS at the above dose induced damaging effects to the reproductive system in male mice, and that GA co‐administration mitigated the adverse actions of WPS measured.

Support or Funding Information

Supported by a joint grant from Sultan Qaboos University and United Arab Emirates University (CL/SQU ‐ UAEU/18/01).
Overexpression of Solute Carrier Family in Ambient Particulate Matter Exposure Fibroblasts Enhances Lung Cancer Progression
Authors: Chang Yu-Chan , Hsiao Michael
Published: April 2020

Ambient Particulate Matter (PM) is considered to be air pollution and is correlated with pulmonary disease, particularly chronic obstructive pulmonary disease (COPD) and cancer. PM contains small particles and liquid droplets which then cause local inflammation and further systemic diseases. Characterization of HPF after PM exposure in lung tumorigenesis. We established transcriptomics through PM exposing to human pulmonary primary fibroblasts (HPF) under time‐course conditions. Our results preformed that PM exposure in HPF cells has upregulated the expression levels of several solute carrier family (SLCs). Therefore, we hypothesized that HPF may pump out or accelerate the production of metabolites to build up a tumor microenvironment. We detected SLC6A6 (taurine transporter), SLC7A11 (cysteine/glutamate transporter), SLC16A6/A7 (monocarboxylate transporter), SLC37A4 (glucose‐6‐phosphate exchanger) and SLC35F1 (lung squamous cell cancer related protein) were increased in HPF models by qPCR analysis. In addition, we demonstrated that the relevant metabolites indeed increased the production of HPF cell culture supernatants. Moreover, we determined that these transporters have been upregulated by immunohistochemical staining in the lung region of the intratracheal injection in vivo model. Furthermore, we processed an indirect co‐culture system between HPF and benign lung cancer cells. We then observed that lung cancer cells can enhance their migration/invasion ability under HPF‐PM exposure culture medium. We also track fluorescence‐based signals from nanobubble‐embbed metabolites in vitro and in vivo. Meanwhile, we recruited analogs of each metabolites or competitors to block with transporters. These data indicate that the phenotype can be reversed in the indirectly culture system. Combining all observations, we concluded that several metabolites may allow fibroblasts to acquire functions similar to cancer‐associated fibroblasts (CAFs). Cancer cells prevent nutrient deprivation by activating metabolic reprogramming of adjacent fibroblasts. These antagonists can serve as a novel strategy for neutralizing the tumor microenvironment of pulmonary diseases.
Eicosapentaenoic Acid Reduces Hepatic Steatosis Independently of UCP1
Authors: Albracht-Schulte Kembra , Wilson Savanna , Pahlavani Mandana , Ramalingam Latha , Festuccia William , Scoggin Shane , Moustaid-Moussa Naima
Published: April 2020

Hepatic steatosis is characterized by excessive accumulation of triglyceride (TG). Mitochondrial membrane uncoupling proteins (UCPs) are potential targets for obesity treatment, given their ability to dissipate energy as heat. Previous studies in our lab have indicated that the omega‐3 polyunsaturated fatty acid, eicosapentaenoic acid (EPA), reduced obesity, inflammation and hepatic steatosis, and upregulated brown adipose tissue UCP1 protein in high fat (HF) fed mice housed at ambient temperature (22–23°C). However, EPA‐mediated improvements were attenuated and were independent of UCP1 when mice were housed in a thermoneutral environment (28–30°C). Thus, the objective of this work is to determine mechanisms of EPA‐mediated improvements in liver steatosis in UCP1 Knockout (KO) mice. Wild type (WT) and UCP1‐KO B6 mice were fed a HF diet with 36 g/kg AlaskOmega, 800mg/g fish oil of EPA (WT‐EPA, KO‐EPA) or without EPA (WT‐HF, KO‐HF) for 14 weeks. Mice were metabolically phenotyped during the feeding period, and histology and molecular analyses were performed in the liver after euthanasia. The KO‐HF group were highest in body weight, while KO‐HF, WT‐HF and WT‐EPA were comparable. Surprisingly, EPA attenuated weight gain in the KO‐EPA group compared to KO‐HF. Further, liver TG levels were significantly reduced in the KO‐EPA group compared to the KO‐HF. Consistent with this finding, EPA upregulated fatty acid beta‐oxidation markers only in the KO‐EPA group, indicated by significant increases in peroxisome proliferator activated receptor‐alpha (Ppara) and carnitine palmitoyltransferase (Cpt) 1a compared to KO‐HF. In conclusion, EPA rescued the detrimental effects of UCP1 deficiency in the livers of HF fed mice in a thermoneutral environment. Further studies are ongoing to dissect mechanistic basis for UCP1‐independent beneficial effects of EPA in liver steatosis. Our promising findings warrant further EPA supplementation studies in humans with obesity, given the limited activity of brown adipose tissue and downregulation of UCP1 in this population.

Support or Funding Information

Funded by NIH/NCCIH grant #R15AT008879‐01A1 (N.M.M.)
Bioengineered Human Acellular Vessels as Dialysis Access Grafts
Authors: Niklason Laura
Published: April 2020

Cardiovascular regenerative medicine has taken many avenues. One approach currently in clinical trials does not require any cells from the patient, and is an engineered tissue that is available “off‐the‐shelf”. Our approach to vascular engineering involves seeding allogeneic vascular cells onto a degradable substrate to culture vascular tissues in a biomimetic bioreactor. After a period of 8–10 weeks, engineered tissues are then decellularized to produce an engineered extracellular matrix‐based graft. The advantage of using allogeneic cells for graft production is that no biopsy need be harvested from the patient, and no patient‐specific culture time is required. These grafts are currently being tested in a Phase III clinical trial in Europe and in the US. Early experience supports the potential utility of this novel tissue engineered vascular graft to provide vascular access for hemodialysis.

The decellularization approach has also allowed us to generate scaffolds to support whole lung regeneration. Using rat, porcine and human sources of organs, lungs have been subjected to a range of decellularization procedures, with the goal of removing a maximal amount of cellular material while retaining matrix constituents. Next‐generation proteomics approaches have shown that gentle decellularization protocols result in near‐native retention of key matrix molecules involved in cell adhesion, including proteoglycans and glycoproteins. Repopulation of the acellular lung matrix with mixed populations of neonatal lung epithelial cells results in regio‐specific epithelial seeding in correct anatomic locations. Survival and differentiation of lung epithelium is enhanced by culture in a biomimetic bioreactor that is designed to mimic some aspects of the fetal lung environment, including vascular perfusion and liquid ventilation. Current challenges involve the production of a uniformly recellularized scaffold within the vasculature, in order to shield blood elements from the collagenous matrix which can stimulate clot formation. In addition, we have developed methods to quantify barrier function of acellular and repopulated matrix, in order to predict functional gas exchange in vivo.

Support or Funding Information

NIH R01 HL127386 (Niklason)
The Hydrodynamic Sensory System in the Skin of Cetaceans
Authors: Eldridge Sherri , Mortazavi Farzad , Rosene Douglas
Published: April 2020

The skin’s sensory afferents have a myriad of varieties, tactile functions and specialized end‐organ receptors enabling species to exploit ecological niches. In typical vertebrate skin, from fish to humans, axons innervate relatively small discreet receptive fields, providing fine‐scale discrimination of texture or location of a pin prick.

The cetacean suborders of Mysticeti (baleen) and Odontoceti (toothed) whales are fully‐aquatic glabrous‐skinned mammals, descendants of terrestrial hairy‐skinned arteriodactyls. Shaped by dynamic forces of the marine environment, nerves in the skin of cetaceans (whales, dolphins and porpoises) have adapted to assess critical aquatic information including current flow, swim turbulence, fish movement and boundary layers, as well as tactile touch, temperature and nociceptive stimuli. The anatomy of this highly‐derived sensory system was investigated in the flank skin of humpback whales (Megaptera novaeangliae, NMFS permits 14809, 15240) using antibodies against highly‐conserved molecules of physiologically‐distinct afferents identified in other mammalian species.

Humpback whales inherited a genomically‐diverse suite of cutaneous axons, including low‐threshold mechanoreceptors that sense innocuous environmental signals, as well as high‐threshold thermoreceptors, chemoreceptors and nociceptors. However, during their transition from terrestrial artiodactyls into obligate marine mammals, axon morphology and organization diverged. Unlike other vertebrates, heterogenous axons in whale skin assemble into thread‐like bundles. These ensembles divide into smaller bundles, follow circuitous trajectories that form unpredictable shapes, and lack structural endings. Developmental research has shown that axonal growth in vertebrates is guided by the skin’s signaling molecules and external physical stimuli. As environmental forces are transmitted through the epidermis they convey stretch at the dermal‐epidermal junction, a mechanically unstable boundary where mechanoreceptors typically reside. While lacking these receptor endings, the whale’s polymodal axon bundles are anatomically positioned at the dermal‐epidermal junction to transduce signals. Similar axon bundles innervation is found in the odontocete Tursiops truncatus (bottlenose dolphins), evidence that this trait is a cetacean synapomorphy. The polymorphic nature of these sensory ensembles may be a tuning mechanism that targets maximal signal strength, detects functionally diverse information (hydrostatic or hydrodynamic forces) or compares attenuation of signal properties at different locations in the skin (frequency, angular velocity or amplitude).

Hallmarks of a hydrodynamically‐tuned system include the capacity to detect and integrate multiple signal properties. In becoming secondarily aquatic mammals, cetaceans have reconstructed the vertebrate somatosensory plan.

Support or Funding Information

NOAA Award #NA10SEC4810008.
Neuroinflammation in Alzheimer’s Disease: Friend or Foe?
Authors: Scuderi Caterina , Facchinetti Roberta , Steardo Luca , Valenza Marta
Published: April 2020

Neuroinflammation is part of the complex immune response within the central nervous system (CNS), whose details have been partially elucidated. The CNS immune response involves elements carried from the periphery and resident elements, mainly represented by glial cells. These cells drive neuroinflammation, which can be roughly defined as an articulated physiological response characterized by the production of a plethora of inflammatory mediators that alter the microenvironment. Growing evidence shows roles for neuroinflammation in the aging brain both in healthy and pathological conditions, including Alzheimer’s disease (AD). AD is a multifactorial neurodegenerative disease of the brain, characterized, at the molecular level, by deposits of beta‐amyloid peptides in the extracellular space and of neurofibrillary tangles inside neurons. Together with abnormal protein deposits, it is now established that neuroinflammation represents the third hallmark found in AD patients’ brains. Many scientists agree that the neuroinflammatory process begins at the earliest phase of AD, bringing both positive and negative consequences. Indeed, the brain immune system recognizes the abnormal accumulation of proteins as injurious stimuli, so it initiates a physiological reaction to defend the brain that includes activation of glial cells and release of proinflammatory molecules. When these processes are protracted, they may contribute independently to neural dysfunction, cell death, thus fostering AD progression. Based on these considerations, targeting pathological gliosis seems to represent a valuable therapeutic approach. Compounds able to control glial activation with a combination of neuroprotective and anti‐inflammatory effects constitute a pool of possible therapeutic drugs to study. By using different in vitro and in vivo models of AD, I demonstrated the presence of important alterations of cerebral homeostasis caused by glial abnormalities. Obtained results have contributed to clarify the possible consequences of glia activation and of the subsequent neuroinflammation, demonstrating the presence of significant (i) alterations of the cerebral cytoarchitecture, (ii) modifications of cerebral metabolism and (iii) neuronal death. My results support the notion that targeting pathological gliosis may represent a promising and innovative therapeutic approach for several brain diseases. However, the effect of therapeutic interventions targeting glial cells depends on reaching the perfect balance between attenuating the deleterious effects and maintain the beneficial mechanisms of brain defense.

Support or Funding Information

This research was supported by the Italian Ministry of Instruction, University and Research (MIUR) to LS, and the SAPIENZA University of Rome to CS.
Cardiac Revascularization Post Myocardial Infarction Enhances Remuscularization and Improves Function
Authors: Vasconcelos Sara Nunes
Published: April 2020

Background

Human induced pluripotent stem cell‐derived cardiomyocytes (hiPSC‐CMs) offer an unprecedented opportunity to remuscularize infarcted human hearts. However, studies show that the majority of hiPSC‐CMs die post transplantation into the ischemic environment, limiting their regenerative potential and clinical application. Death of transplanted CMs occurs in the first few days post‐transplantation due to ischemia. Thus, attempts have been made to promote blood perfusion (i.e. addition of endothelial cells and/or angiogenic factors). However, these approaches require weeks for new vessels to form and to carry blood compared to the rapid death of transplanted CMs (2–3 days).

Purpose

Our goal was to improve the vascularization of the ischemic hearts to improve the survival of hiPSC‐CMs and increase heart remuscularization and function.

Methods

We performed left anterior descending artery (LAD) ligation in immunocompromised rats to model myocardial infarction. To improve vascularization, we used an innovative strategy consisting of ready‐made microvessels isolated from adipose tissue that form a vasculature and carry blood within the first days post subcutaneous implantation. We have co‐implanted ready‐made microvessels with hiPSC‐CMs by intra‐myocardial injection 2 weeks post LAD ligation. Cardiac function was assessed at 0, 2 and 4 weeks post‐implantation by echocardiography and by pressure‐volume loop at the endpoint (4 weeks). Immunohistochemistry and blood perfusion studies were performed at 1 and 4 weeks post‐implantation.

Results

Compared to hiPSC‐CM transplantation alone, microvessels promoted a ~600% increase in hiPSC‐CM survival with significant reduction in scar size. Echocardiography and pressure–volume (PV) loop analysis performed 4 weeks post‐MI revealed that hiPSC‐CM transplantation attenuated post‐infarct ventricular dilation and enhanced left ventricular contractility by demonstrating a significant improvement in fractional shortening (FS), ejection fraction (EF) as well as other functional parameters (end‐systolic volume, end‐diastolic volume, dP/dt max and min, Tau). Remarkably, co‐transplantation of hiPSC‐CMs with microvessels showed significantly superior functional recovery compared to hiPSC‐CMs alone in all the parameters assessed. Microvessels showed remarkable persistence and integration at both early and late time points, resulting in significantly faster blood perfusion and higher vessel density in the grafts.

Conclusion

These findings provide a novel approach to cell‐based therapies for myocardial infarction whereby incorporation of ready‐made microvessels can serve as a personalized delivery system to improve functional outcomes in cell replacement therapies post‐myocardial infarction.

Support or Funding Information

Canadian Institutes of Health Research (CIHR), Institute of Circulatory and Respiratory Health grant #137352 and #PJT153160. Discovery grant from the Natural Sciences and Engineering Research Council (NESERC): RGPIN 06621‐2017.
Allogeneic stem cell therapy for cardiac repair and host immune response
Authors: Dhingra Sanjiv , Abu-l-Rub Ejlal , Sequiera Glen Lester , Sareen Niketa , moudgil Meenal
Published: April 2020

Bone marrow derived allogeneic (unrelated donor) mesenchymal stem cells (MSCs) and induced pluripotent stem cell‐derived cardiomyocytes (iPSC‐CMs) have been found to have a high potential as candidates for cardiac repair. Unlike embryonic stem cells, there are no ethical issues involved with these two cell types. Both can help in replacing the dead cells directly/indirectly. Even though initial pre‐clinical and clinical trials showed promise for using MSCs and iPSC‐CMs, but after transplantation, these cells were found to be rejected by the recipient immune system that led to deterioration of beneficial effects of stem cell based therapies. Therefore, we aim to decipher the mechanisms responsible for the rejection of the transplanted allogeneic MSCs and iPSC‐CMs by the host immune system. The immunoprivilige of allogeneic MSCs is preserved by absence of cell surface immune antigen, major histocompatibility complex (MHC)–II. We recently found that MHC‐II expression increased in rat and human MSCs after exposure to hypoxia or after transplantation in the infarcted rat heart. MHC‐II expression is regulated by a class II transactivator (CIITA). We found that hypoxic environment led to upregulation of ATPase subunit of 19S proteasome Sug1 and its binding to CIITA, that was associated with activation of CIITA and upregulation of MHC‐II expression. As a result, MSCs became immunogenic and were rejected by host immune system. Knocking down Sug1 in MSCs preserved immunoprivilege and prevented rejection of transplanted MSCs in the infarcted heart. In case of iPS cells, we found that after differentiation to cardiomyocytes there was a significant increase in the MHC‐II expression that was associated with upregulation of immunogenicity of iPSC‐CMs. Therefore, current study provides novel mechanisms of increase in immunogenicity of allogeneic MSCs and iPSC‐CMs. This study may help in facilitating a better planning for future MSCs or iPSC based clinical trials in cardiac patients.

Support or Funding Information

Canadian Institutes of Health Research
The Use of Magnetic Nanoparticles to Alter Primary Cilia Structure and Function
Authors: Nauli Surya M. , Pala Rajasekharreddy
Published: April 2020

Primary cilia are non‐motile cell organelles with sensory functions. Abnormal cilia structure or function results in disorders, collectively termed as ciliopathies. Ciliopathies include an expanding spectrum of cardiovascular diseases, including hypertension. Microenvironment has directly implicated in an early stage of ciliopathy. Thus, the next nano‐material advances for a cilia‐targeted therapy or ciliotherapy are a desirable approach to treat ciliopathies. We report here that we have generated cilia‐targeted iron oxide (Fe2O3) nanoparticles that offer a new prototype in ciliotherapy. Live‐imaging of single‐cell‐single‐cilium analysis confirmed that the magnetic nanoparticles specifically targeted to primary cilia, making it possible to remotely control the movement and function of cilia with the external magnetic field. When these nanoparticles were loaded with fenoldopam, selected as a candidate drug prototype, the magnetic field accelerated the release of fenoldopam faster than a standard diffusion. A more sustained increase in cytosolic and intraciliary calcium (Ca2+) signaling and release of nitric oxide (NO) were observed only when magnetic field was applied. Importantly, the cardiovascular phenotypes in the ciliopathy models were improved with magnetic field. Our studies suggest that nanoparticles can be used to alter molecular and mechanical property of primary cilia.

Support or Funding Information

This work was supported by the National Institute of Health (HL131577), Congressionally Directed Medical Research Program (PR130153) and American Heart association (19IPLOI34730020)