bluuebunny/crossref_metadata_2025_split huggingface dataset:
IMP1/IGF2BP1 alters extracellular vesicle cargo in colorectal cancer
Authors: Kuhn Madeline , Zhang Yang , Armstrong Randall , Andres Sarah 
Published: May 2022

BackgroundColorectal cancer (CRC) is the third leading cause of cancer‐related death worldwide. There is an urgent need for new therapeutic targets and methods of early detection to improve patient outcomes. Extracellular Vesicles (EVs) and EV cargo are promising new biomarkers and therapeutic targets. EVs are secreted nanoparticles that carry DNA, RNA, and proteins. EVs can target specific cell types and once taken up by a destination cell, EV cargo can shape cell gene expression and physiology. EVs can shape the tumor microenvironment (TME) (i.e., stromal, immune, and endothelial cells), which plays critical roles in patient survival and disease outcomes. Our current understanding of how EV cargo is determined and how it influences the CRC cell TME is limited. One promising but understudied molecular aspect of EVs is RNA binding proteins (RNAbps). RNAbps are post‐transcriptional regulators of gene expression and could provide a link between host cell gene expression and EV cargo. Insulin‐like growth factor 2 RNA binding protein 1 (IMP1, IGF2BP1) is an RNAbp with a critical role in CRC development and progression. IMP1 is expressed highly in CRC tumors, expression correlates with worse prognosis, and IMP1 binds/potently regulates tumor‐associated transcripts. How EV cargo is influenced by IMP1 and effects on EV targeting to destination cells and on target cell gene expression and function is not known. Understanding how IMP1 shapes EV cargo and which TME cells are targeted, will identify new mechanisms of cancer development/progression through IMP1‐EV‐mediated alteration of the TME and novel EV cargo as candidates for early detection biomarkers.HypothesisWe hypothesize that IMP1 facilitates the packaging of tumor‐promoting EV cargo that interact and communicate with the TME to enhance tumor progression.MethodsEVs were isolated from IMP1 null and IMP1‐overexpressing (IMP1OE) CRC cell lines, HT‐29, SW480, as well as wildtype Caco2 cells (express high levels of IMP1) by size‐exclusion chromatography. EVs were assessed by nanoparticle tracking analysis, western blot, electron microscopy, and qPCR.ResultsWe found that IMP1 enters EVs from Caco2 and SW480 IMP1OE cell lines, but not HT‐29 IMP1OE or corresponding null controls. IMP1 did not alter EV secretion in CRC cell lines. We found that IMP1 target mRNAs, such as KRAS, cMYC are present within EVs, but not the IMP1 target PTGS2.ConclusionsOur novel findings suggest that IMP1 enters the EV to directly influence EV cargo in specific CRC cell lines. Our findings have implications for the development of novel early detection biomarkers and therapeutic approaches in CRC.
Critical Environmental Limit Protocol: Validity and Reliability (PSU HEAT)
Authors: Cottle Rachel M. , Wolf S. T. , Lichter Zachary S. , Kenney W. L. 
Published: May 2022

With increasing average global temperatures and greater frequency, duration, and severity of heat waves, there is an urgent need to better understand the specific environmental temperatures that place humans at greater risk of heat‐related morbidity and mortality. An incremental heat stress protocol can be used to establish critical environmental limits for human heat exchange, i.e., those combinations of ambient temperature and humidity above which heat stress becomes uncompensable and, therefore, unsafe. However, no studies have rigorously investigated the reliability and validity of this experimental paradigm.PURPOSEHere, we assessed the (1) between‐visit repeatability and (2) validity of an experimental paradigm that either holds ambient vapor pressure (Pa) constant and incrementally increases dry‐bulb temperature (Tdb) or vice versa.METHODSTwelve subjects (5M/7W; 25±4 yr) completed a progressive heat stress protocol during which they walked on a treadmill (2.2 mph, 3% gradient) in a controllable environmental chamber while gastrointestinal temperature (Tgi) was continuously monitored. After an equilibration period, the progressive heat stress protocol involved increasing Tdb every 5 min while Pa was held constant (Tcritexperiments), or increasing Pa every 5 min while Tdb was held constant (Pcritexperiments), until an upward inflection and continuous rise in Tgi was observed. The Tcrit or Pcrit was identified as the average Tdb or Pa, respectively, across the 2 min preceding the Tgi inflection point. For repeatability experiments, 11 subjects returned to the lab to repeat the same protocol as their first visit. For validity experiments, 10 subjects returned to the lab for a progressive heat stress trial in which Tdb or Pa was held constant at the Tcrit or Pcrit value from their first visit.RESULTSThe between‐visit repeatability for critical environmental limits was excellent (ICC = 0.98). Similarly, there was excellent agreement between original and validity trials for Tdb (ICC = 0.95) and Pa (ICC = 0.96) at the Tgi inflection point. Furthermore, the wet‐bulb temperature at the Tgiinflection point was not different during reliability (p = 0.78) or validity (p = 0.32) trials compared to original trials.CONCLUSIONTogether, these data provide strong evidence that this experimental paradigm is rigorous, reliable, and valid, supporting its use to investigate critical environmental limits to the maintenance of heat balance.
Model for Calcium‐Dependent Activation of a Type I Metacaspase From the Fungus Schizophyllum commune
Authors: Coyle Timothy F. , Fox Kristin M. 
Published: May 2022

Apoptosis or programmed cell death (PCD) is one of the most important cellular processes which functions to avoid the accumulation of mutations or damage within a cell. PCD has been extensively studied in eukaryotic cells, demonstrating that caspase proteins have a significant role in this process. However, unlike mammalian cells, caspase genes are absent in plants, fungi, and protozoa. Instead, these organisms contain homologous proteins known as metacaspases which have demonstrated similar proteolytic functions in aiding PCD. Determining an accurate model for how these metacaspases are activated could provide insight into the methods behind this protease‐dependent cell death which could lead to further strategies for the regulation of fungal infections. This research focuses on the model of activation for the Type I metacaspases from the fungus Schizophyllum commune. The S. commune Type I metacaspases are dependent on calcium ions for activation; however, the molecular mechanism behind how calcium activates this protease remains unknown.It has been proposed that when calcium binds to the metacapsape, these ions induce a structural rearrangement of the active‐site region leading to activation. To further understand how calcium and other divalent metallic cations influence the activation of this protease, we used kinetic activity assays to quantify metacaspase activity and differential scanning fluorimetry to measure divalent metallic cation‐metacaspase binding.In addition to strong activation by calcium, manganese ions have demonstrated a moderate effect on metaspace activity, while magnesium, copper, samarium, and cobalt don’t affect activity. We will present evidence that calcium binds to two sites on the protein, while manganese binds to only a single site. Furthermore, calcium binding to the Type I metacapses occurs at two sites with affinities that differ by several orders of magnitude. Initial results suggest that it is necessary for calcium to saturate the high affinity site prior to binding to the low affinity site. Thus, it has been predicted that calcium’s initial saturation of the high affinity site induces slight conformation changes to the active‐site; however, once the low affinity site has been saturated, an active‐site loop undergoes further rearrangements resulting in metacaspase activation. Further analysis of binding interactions between the Type I metacapse and calcium (along with other divalent cations) will provide insight into how these structural rearrangements lead to increased metacaspase activity.
Identification of NUAK1/2 Regulators in the Hippo Signaling Pathway
Authors: Song Youchen , Gill Mandeep K. , Song Siyuan , Attisano Liliana 
Published: May 2022

The Hippo signaling pathway plays a central role in regulating cell proliferation, differentiation, and tissue size. In response to various upstream regulators, the mammalian STE20‐like protein kinase 1/2 (MST1/2) and large tumor suppressor kinase 1/2 (LATS1/2) phosphorylate Yes‐associated protein (YAP) and transcriptional co‐activator with PDZ‐binding motif (TAZ) to promote their cytoplasmic retention and degradation. Unphosphorylated YAP/TAZ translocate into the nucleus and interact with several transcription factors to regulate gene expression that drives cell growth and migration. Dysregulation of the Hippo pathway causes tissue overgrowth and tumorigenesis and elevated YAP/TAZ levels or activities are positively correlated with progression of almost all solid cancers. The NUAK family kinase 1/2 (NUAK1/2) are members of the AMP‐activated protein kinase‐related kinase family. Our lab showed that NUAK2 negatively regulates the Hippo pathway by preventing LATS‐mediated YAP/TAZ phosphorylation and cytoplasmic sequestration. Moreover, this work showed that loss of NUAK2 attenuates in vivo mammary tumor growth. However, how NUAK1/2 are regulated is poorly understood.Here, we will undertake screens in cancer cell lines to identify upstream and downstream NUAK1/2 regulators and partners. Since, abrogation of NUAK expression blocks cell growth in a context‐dependent manner, my current efforts are being directed towards generating cell lines expressing inducible NUAK1/2 shRNAs. Independent clones have been selected and validated for their knockdown efficiencies and effects on YAP/TAZ downstream target gene expression. Once validated, the selected lines will be subjected to genome‐wide CRISPR screens. We hypothesize that the screens will identify components that enhance or attenuate the effect of NUAKs and will reveal any differential regulators and partners for NUAK1/2. Discovering novel cancer‐relevant NUAK regulators will enhance our understanding of the tumor promoting roles of NUAKs and provide insights into how to target these kinases for better therapeutic outcomes.
The Influence of Activin on the Tumor Microenvironment in Colon Cancer Metastasis
Authors: Wiley Mark B. , Bauer Jessica , Mehrotra Kunaal , Zessner‐Spitzenberg Jasmin , Kone Lyonell , Quiao Guilin , Castellanos Karla , Church David N. , Kerr Rachel S. , Kerr David J. , Grippo Paul , Maker Ajay , Jung Barbara 
Published: May 2022

Background and AimsTGFβ and activin A are key molecules regulating tumor growth, inflammatory responses in the TME, and have differential effects which are receptor and cell specific. Identification of the source of activin A/TGFβ production and site of signaling will be critical for directing therapeutic development. Here, we employ both mouse models and human tissue samples to 1) identify pathways in which SMAD4 mutations exacerbate tumor growth and metastasis, 2) recognize how TGFβ and activin A signaling are influencing immune responses in the TME, and 3) to use the cellular source and signaling of activin A, rather than the amount, to predict patient outcomes in CRC. We have previously shown elevated levels of circulating activin A in stage IV CRC patients and that activin signaling promotes epithelial to mesenchymal transition and migration. We now hypothesize that activin A signaling pathways have distinct effects on immune cells and tumor cells which regulate tumor development and metastasis of CRC.MethodsKnockdown of activin A was assessed in a surgical colon cancer liver metastases mouse model. The influence of the SMAD4‐dependent, canonical pathway was elucidated in a Ts4‐Cre; cApcflox;Smad4flox (TcAS) mouse model for colon cancer. Western blotting and migration assays were performed on human colon cancer cells with mutations in receptors for TGFꞵ and/or activin to determine functional interactions of the downstream pathways. We used a TMA of 1054 CRC patients with stage II and III colon cancer from the QUASAR2 cohort to correlate activin and TGFb expression with outcome.ResultsThe non‐canonical pathway pAKT is activated in ACVR2 restored HCT116+chr2 colon cancer cells, but not in ACVR2 mutated cells. Ablation of the the activin A canonical pathway target SMAD4 in mice leads to decreased survival in colon cancer mouse model and pERK is increased in SMAD4‐/‐ knock out mice and correlates with dysplasia grade. Mice harboring colonic lesions with high stroma content were positive for activin A and CAF marker α‐SMA and have shorter median survival. Activin knockdown in mouse metastasis model leads to decreased tumor growth. Patient data revealed that a high ratio of activin A relative to TGFꞵ in the tumor epithelium, but not in the stroma, is associated with an increased survival rate. Ongoing studies are being conducted to determine if activin A is being localized to immune cells interacting with the tumor epithelium which may be promoting anti‐tumor activity in these patients.ConclusionRecent clinical trials explored the feasibility of activin A and TGFβ blockade in solid tumors. Data presented here supports complex and intertwined roles for activin and TGFβ signaling in colorectal cancer, both in immune activation as well as metastatic spread of advanced cancers.
Skeletal Muscle Oxygen Delivery and Utilization during Exercise in Heart Failure with Preserved Ejection Fraction: Role of Sympathetic (α‐adrenergic) Vasoconstriction
Authors: Alpenglow Jeremy , Bunsawat Kanokwan , Fancisco Michael , Weavil Josh , Broxterman Ryan , Iacovelli Jarred , Harrison Jon , Morgan David E. , Ryan John J. , Ma Chisty L. , Wray D. W. 
Published: May 2022

BACKGROUNDHeart Failure with preserved ejection fraction (HFpEF) is characterized by severe exercise intolerance underpinned by low aerobic capacity (VO2peak). It is likely low VO2peak in HFpEF is not only related to deficits in cardiac function, but also peripheral vascular and skeletal muscle dysfunction that may disrupt the balance between O2 delivery and utilization. There is emerging evidence for sympathetic nervous system overactivity in patients with HFpEF that results in excessive vasoconstriction in the peripheral circulation, and may therefore contribute to dysregulation of exercising muscle blood flow. We tested the hypothesis that pharmacological blockade of sympathetic (α‐adrenergic) vasoconstriction would increase blood flow, O2 delivery and utilization of exercising skeletal muscle to a greater extent in HFpEF compared to healthy control subjects.METHODSFour healthy control (CON) (2 M, 69±3 yrs) and three HFpEF (1 M, 71±3) volunteers participated in this study. Femoral blood flow (FBF) was assessed by ultrasound Doppler. Catheters were placed in the femoral artery and vein for drug infusions and determination of arterial and venous O2 content (CaO2 and CvO2, respectively). O2 utilization of the exercising leg was calculated via the Fick equation: VO2 = FBF∙(CaO2‐CvO2), and O2 delivery was calculated as FBF∙CaO2. Measurements were made at rest and during dynamic single‐leg knee‐extension (KE) exercise (5 W) before and after intra‐arterial infusion of the α‐adrenergic antagonist phentolamine (PHEN).RESULTSBaseline FBF, O2 delivery, and VO2 were similar between groups. At rest, PHEN increased FBF and O2 delivery similarly in both groups, while the increase in VO2 tended to be smaller in patients with HFpEF compared to CON (+3±2 vs. +14±5 ml/min; respectively, P=0.09). During KE exercise, a ≍20‐30% decrement in FBF (2052±261 vs. 2529±230 ml/min; HFpEF vs. CON, P=0.23), O2 delivery (282±27 vs. 392±35 ml/min, HFpEF vs. CON, P=0.07), and VO2 (193±25 vs. 284±31 ml/min; HFpEF vs. CON, P=0.09) were observed in patients with HFpEF. PHEN increased exercising muscle FBF (+243±45 vs. +247±58 ml/min; HFpEF vs. CON) and O2 delivery (+51±9 vs. +34±19 ml/min; HFpEF vs. CON) similarly between groups, while the PHEN‐induced increase in VO2 tended to be greater in patients with HFpEF (+20±12 vs. +6±7 ml/min; HFpEF vs. CON, P=0.32).CONCLUSIONTaken together, these preliminary data suggest a reduction in FBF, O2 delivery and utilization during small muscle mass exercise in patients with HFpEF that may be, in part but not fully, explained by excessive sympathetic (α‐adrenergic) vasoconstriction in this patient group.
Role of S‐nitrosoglutathione reductase (GSNOR) Dysregulation and Nitrosative Stress in Heart Failure With Preserved Ejection Fraction
Authors: LaPenna Kyle B. , Li Zhen , Sharp Thomas E. , Mose Karl H. , Doiron Jake E. , Xia Huijing , Goodchild Traci T. , Lefer David J. 
Published: May 2022

BackgroundHeart failure with preserved ejection fraction (HFpEF) is the most predominant form of heart failure in the United States. This multi‐system pathology results in a 5‐year mortality rate for which there are very few treatment options. The obese ZSF1 rat model has previously been shown to recapitulate much of the human phenotype including obesity, metabolic syndrome, diabetes, and hypertension. In this study, we investigated the complex and largely unknown role of abnormal nitric oxide signaling and nitrosative stress in the pathobiology of HFpEF.Materials and MethodsMale ZSF1 rats and normotensive controls of Wistar Kyoto (WKY) background strain (n=7 each group) were studied at 10, 14 and 18 weeks of age to monitor disease progression and alterations in nitric oxide signaling. Cardiac protein nitrosylation (RxNO) was measured by chemiluminescence. Analysis of circulating plasma nitrite bioavailability was performed using high performance liquid chromatography. GSNOR, one of the enzymes that degrade nitrosothiols, mRNA expression was measured and plotted as relative fold difference to WKY expression in this model of cardiometabolic HFpEF.ResultsZSF1 rats exhibited significantly increased cardiac protein nitrosylation as the HFpEF phenotype progressed from 10 to 18 weeks of age as compared to the WKY rat group. GSNOR mRNA expression was significantly decreased in the ZSF1 rat relative to the WKY at all time points. During the later 18‐week timepont, cardiac GSNOR activity was found to be decreased compared to that of the WKY. Circulating plasma nitrite, a measure of eNOS function, was decreased in the ZSF1 rat at 14 and 18 weeks compared to the WKY at subsequent aging timepoints. These data correlate to an increasing left ventricular end diastolic pressure (LVEDP) and decreased vascular relaxation as the ZSF1 animals age and develop more severe HFpEF disease pathology.ConclusionOur data suggests that nitric oxide signaling is dysregulated in the setting of HFpEF resulting in a significant increase in cardiac protein nitrosylation coupled with a reduction in circulating nitrite and NO signaling in the vasculature. Excessive cardiac nitrosative stress resulting in pathological myocardial signaling has been previously implicated as a driver of HFpEF. Reduced vascular nitrite bioavailability resulting in attenuated physiological NO signaling could account for the profound vascular dysfunction observed in HFpEF patients. Future studies are aimed at the further elucidation of the role of various NO storage pools in HFpEF.
Compromised endothelial progenitor cell exosomal communication with endothelial cells in hypertension ischemia conditions
Authors: Wang Jinju , Chen Shuzhen , Polaki Venkata , Sawant Harshal , Bihl Ji 
Published: May 2022

BackgroundWe have previously demonstrated that EPC‐exosomes (EPC‐EXs) can protect endothelial cells (ECs) against hypoxia injury in vitro. What's more, we found that extracellular vesicles released from starved EPCs have opposite functions to those released in inflammation conditions, suggesting that EPC‐EXs‐mediated communication is functional and modulable by factors that affect the status of their parent cells. Given clinical studies showing the function of EPCs is declined in patients with hypertension, we speculate the EPC‐EX mediated communication with ECs is impaired in hypertension‐ischemia conditions.MethodsEPC‐EXs were prepared from the bone marrow EPCs of wild type (WT) and hypertensive renin transgene (R+) mice and were denoted as WT‐EPC‐EXs and R‐EPC‐EXs, respectively. To mimic hypertension‐ischemia injury, ECs were treated with angiotensin II (10‐6 M) plus hypoxia (1% O2 for 6 hrs) and reoxygenation (21% O2 for 24 hrs). To determine the function of EPC‐EXs, ECs were co‐cultured with EXs for 24hrs. EX uptake efficiency, cellular viability and function were assessed.Results1) The incorporation efficiency of EPC‐EXs from R+ mice by ECs were decreased. 2) Angiotensin II plus hypoxia reoxygenation‐injured ECs displayed decreased cell viability, increased cell apoptosis and compromised angiogenic ability. 3) R‐EPC‐EXs displayed the impaired capability of rescuing ECs and improving their angiogenic ability on ECs as compared to that of WT‐EPC‐EXs did.ConclusionOur data have suggested that EPC‐EXs mediated communication of EPC/EC is compromised in R+ mice hypertension‐ischemia conditions. These findings suggest that impairment of EPC exosomal communication might contribute to the exaggerated cerebral ischemia injury in hypertension‐associated ischemic stroke.